Journal articles on the topic 'Locally parametric methods'
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Penev, Spiridon, and Kanta Naito. "Locally robust methods and near-parametric asymptotics." Journal of Multivariate Analysis 167 (September 2018): 395–417. http://dx.doi.org/10.1016/j.jmva.2018.06.006.
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Cheng, Ming-Yen, Edwin Choi, Jianqing Fan, and Peter Hall. "Skewing Methods for Two-Parameter Locally Parametric Density Estimation." Bernoulli 6, no. 1 (February 2000): 169. http://dx.doi.org/10.2307/3318637.
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A. Hamad, Sarwar, and Kawa S. Mohamed Ali. "A Comparative Study of Nearest Neighbor Regression and Nadaraya Watson Regression." Academic Journal of Nawroz University 10, no. 2 (May 24, 2021): 180–88. http://dx.doi.org/10.25007/ajnu.v10n2a505.
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Two non-parametric statistical methods are studied in this work. These are the nearest neighbor regression and the Nadaraya Watson kernel smoothing technique. We have proven that under a precise circumstance, the nearest neighborhood estimator and the Nadaraya Watson smoothing produce a smoothed data with a same error level, which means they have the same performance. Another result of the paper is that nearest neighborhood estimator performs better locally, but it graphically shows a weakness point when a large data set is considered on a global scale.
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Bolešová, Mária, Katarína Gajdošová, and Marek Čuhák. "Reconstruction Effectiveness of Locally Supported Flat Slabs to Increase in Shear Resistance." Solid State Phenomena 309 (August 2020): 246–51. http://dx.doi.org/10.4028/www.scientific.net/ssp.309.246.
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The most used horizontal load-bearing systems in concrete buildings are flat slabs. The effective and economic reconstruction of a locally supported flat slab of an existing building creates a complex task. Shear stress arises near the column and it becomes critical in design with increasing slab slenderness and requires a more detailed calculation. Increasing in the shear resistance of the flat slab can be achieved in various ways. Each method brings different effectiveness, advantages and disadvantages. The most widely used methods of the reconstruction are the increase in the size of the column (therein increasing the control perimeter for displaying the shear stress), the increase in the thickness of the flat slab or reinforcing the slab with shear reinforcement. Bolts and screw anchors (using different mounting angles) can be used as shear reinforcement. Each mentioned reconstruction method should be subjected to numerical calculations and verification of its efficiency. The parametric study presented in this paper is focused on the reconstruction techniques and their verification according to various numerical models. The results from Eurocode 2, fib Model Code 2010 and the new generation of Eurocode 2 are compared to show the differences between them. The aim of this paper is to bring a demonstration of the reconstruction methods that will increase in the shear resistance of the locally supported flat slabs and trying to choose the most effective one.
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Yu, Xu, Jun-yu Lin, Feng Jiang, Jun-wei Du, and Ji-zhong Han. "A Cross-Domain Collaborative Filtering Algorithm Based on Feature Construction and Locally Weighted Linear Regression." Computational Intelligence and Neuroscience 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/1425365.
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Cross-domain collaborative filtering (CDCF) solves the sparsity problem by transferring rating knowledge from auxiliary domains. Obviously, different auxiliary domains have different importance to the target domain. However, previous works cannot evaluate effectively the significance of different auxiliary domains. To overcome this drawback, we propose a cross-domain collaborative filtering algorithm based on Feature Construction and Locally Weighted Linear Regression (FCLWLR). We first construct features in different domains and use these features to represent different auxiliary domains. Thus the weight computation across different domains can be converted as the weight computation across different features. Then we combine the features in the target domain and in the auxiliary domains together and convert the cross-domain recommendation problem into a regression problem. Finally, we employ a Locally Weighted Linear Regression (LWLR) model to solve the regression problem. As LWLR is a nonparametric regression method, it can effectively avoid underfitting or overfitting problem occurring in parametric regression methods. We conduct extensive experiments to show that the proposed FCLWLR algorithm is effective in addressing the data sparsity problem by transferring the useful knowledge from the auxiliary domains, as compared to many state-of-the-art single-domain or cross-domain CF methods.
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Leppink, Jimmie. "Small numbers are an opportunity, not a problem." Scientia Medica 31, no. 1 (June 30, 2021): e40128. http://dx.doi.org/10.15448/1980-6108.2021.1.40128.
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Aims: outcomes of research in education and training are partly a function of the context in which that study takes place, the questions we ask, and what is feasible. Many questions are about learning, which involves repeated measurements in a particular time window, and the practical context is usually such that offering an intervention to some but not to all learners does not make sense or is unethical. For quality assurance and other purposes, education and training centers may have very locally oriented questions that they seek to answer, such as whether an intervention can be considered effective in their context of small numbers of learners. While the rationale behind the design and outcomes of this kind of studies may be of interest to a much wider community, for example to study the transferability of findings to other contexts, people are often discouraged to report on the outcomes of such studies at conferences or in educational research journals. The aim of this paper is to counter that discouragement and instead encourage people to see small numbers as an opportunity instead of as a problem.Method: a worked example of a parametric and a non-parametric method for this type of situation, using simulated data in the zero-cost Open Source statistical program R version 4.0.5.Results: contrary to the non-parametric method, the parametric method can provide estimates of intervention effectiveness for the individual participant, account for trends in different phases of a study. However, the non-parametric method provides a solution in several situations where the parametric method should be used.Conclusion: Given the costs of research, the lessons to be learned from research, and statistical methods available, small numbers should be considered an opportunity, not a problem.
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Escamilla-Rivera, Celia, Jackson Levi Said, and Jurgen Mifsud. "Performance of non-parametric reconstruction techniques in the late-time universe." Journal of Cosmology and Astroparticle Physics 2021, no. 10 (October 1, 2021): 016. http://dx.doi.org/10.1088/1475-7516/2021/10/016.
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Abstract In the context of a Hubble tension problem that is growing in its statistical significance, we reconsider the effectiveness of non-parametric reconstruction techniques which are independent of prescriptive cosmological models. By taking cosmic chronometers, Type Ia Supernovae and baryonic acoustic oscillation data, we compare and contrast two important reconstruction approaches, namely Gaussian processes (GP) and the Locally weighted Scatterplot Smoothing together with Simulation and extrapolation method (LOESS-Simex or LS). In the context of these methods, besides not requiring a cosmological model, they also do not require physical parameters in their approach to their reconstruction of data (but they do depend on statistical hyperparameters). We firstly show how both GP and LOESS-Simex can be used to successively reconstruct various data sets to a high level of precision. We then directly compare both approaches in a quantitative manner by considering several factors, such as how well the reconstructions approximate the data sets themselves to how their respective uncertainties evolve. In light of the puzzling Hubble tension, it is important to consider how the uncertain regions evolve over redshift and the methods compare for estimating cosmological parameters at current times. For cosmic chronometers and baryonic acoustic oscillation compiled data sets, we find that GP generically produce smaller variances for the reconstructed data with a minimum value of σGP-min = 1.1, while the situation for LS is totally different with a minimum of σLS-min = 50.8. Moreover, some of these characteristics can be alleviate at low z, where LS presents less underestimation in comparison to GP.
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Bhardwaj, Divya, Archya Dasgupta, Daniel DiCenzo, Stephen Brade, Kashuf Fatima, Karina Quiaoit, Maureen Trudeau, et al. "Early Changes in Quantitative Ultrasound Imaging Parameters during Neoadjuvant Chemotherapy to Predict Recurrence in Patients with Locally Advanced Breast Cancer." Cancers 14, no. 5 (February 28, 2022): 1247. http://dx.doi.org/10.3390/cancers14051247.
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Background: This study was conducted to explore the use of quantitative ultrasound (QUS) in predicting recurrence for patients with locally advanced breast cancer (LABC) early during neoadjuvant chemotherapy (NAC). Methods: Eighty-three patients with LABC were scanned with 7 MHz ultrasound before starting NAC (week 0) and during treatment (week 4). Spectral parametric maps were generated corresponding to tumor volume. Twenty-four textural features (QUS-Tex1) were determined from parametric maps acquired using grey-level co-occurrence matrices (GLCM) for each patient, which were further processed to generate 64 texture derivatives (QUS-Tex1-Tex2), leading to a total of 95 features from each time point. Analysis was carried out on week 4 data and compared to baseline (week 0) data. ∆Week 4 data was obtained from the difference in QUS parameters, texture features (QUS-Tex1), and texture derivatives (QUS-Tex1-Tex2) of week 4 data and week 0 data. Patients were divided into two groups: recurrence and non-recurrence. Machine learning algorithms using k-nearest neighbor (k-NN) and support vector machines (SVMs) were used to generate radiomic models. Internal validation was undertaken using leave-one patient out cross-validation method. Results: With a median follow up of 69 months (range 7–118 months), 28 patients had disease recurrence. The k-NN classifier was the best performing algorithm at week 4 with sensitivity, specificity, accuracy, and area under curve (AUC) of 87%, 75%, 81%, and 0.83, respectively. The inclusion of texture derivatives (QUS-Tex1-Tex2) in week 4 QUS data analysis led to the improvement of the classifier performances. The AUC increased from 0.70 (0.59 to 0.79, 95% confidence interval) without texture derivatives to 0.83 (0.73 to 0.92) with texture derivatives. The most relevant features separating the two groups were higher-order texture derivatives obtained from scatterer diameter and acoustic concentration-related parametric images. Conclusions: This is the first study highlighting the utility of QUS radiomics in the prediction of recurrence during the treatment of LABC. It reflects that the ongoing treatment-related changes can predict clinical outcomes with higher accuracy as compared to pretreatment features alone.
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Noh, Yung-Kyun, Masashi Sugiyama, Song Liu, Marthinus C. du Plessis, Frank Chongwoo Park, and Daniel D. Lee. "Bias Reduction and Metric Learning for Nearest-Neighbor Estimation of Kullback-Leibler Divergence." Neural Computation 30, no. 7 (July 2018): 1930–60. http://dx.doi.org/10.1162/neco_a_01092.
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Nearest-neighbor estimators for the Kullback-Leiber (KL) divergence that are asymptotically unbiased have recently been proposed and demonstrated in a number of applications. However, with a small number of samples, nonparametric methods typically suffer from large estimation bias due to the nonlocality of information derived from nearest-neighbor statistics. In this letter, we show that this estimation bias can be mitigated by modifying the metric function, and we propose a novel method for learning a locally optimal Mahalanobis distance function from parametric generative models of the underlying density distributions. Using both simulations and experiments on a variety of data sets, we demonstrate that this interplay between approximate generative models and nonparametric techniques can significantly improve the accuracy of nearest-neighbor-based estimation of the KL divergence.
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Feldmann, Kira, Michael Scheuerer, and Thordis L. Thorarinsdottir. "Spatial Postprocessing of Ensemble Forecasts for Temperature Using Nonhomogeneous Gaussian Regression." Monthly Weather Review 143, no. 3 (February 27, 2015): 955–71. http://dx.doi.org/10.1175/mwr-d-14-00210.1.
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Abstract Statistical postprocessing techniques are commonly used to improve the skill of ensembles from numerical weather forecasts. This paper considers spatial extensions of the well-established nonhomogeneous Gaussian regression (NGR) postprocessing technique for surface temperature and a recent modification thereof in which the local climatology is included in the regression model to permit locally adaptive postprocessing. In a comparative study employing 21-h forecasts from the Consortium for Small Scale Modelling ensemble predictive system over Germany (COSMO-DE), two approaches for modeling spatial forecast error correlations are considered: a parametric Gaussian random field model and the ensemble copula coupling (ECC) approach, which utilizes the spatial rank correlation structure of the raw ensemble. Additionally, the NGR methods are compared to both univariate and spatial versions of the ensemble Bayesian model averaging (BMA) postprocessing technique.
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Chang, K. J., W. Fisher, D. Kenady, J. Klapman, M. Posner, T. Reid, A. Rosemurgy, R. Shah, E. Zervos, and D. Laheru. "Multicenter randomized controlled phase III clinical trial using TNFerade (TNF) with chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC): Interim analysis (IA) of overall survival (OS)." Journal of Clinical Oncology 27, no. 15_suppl (May 20, 2009): 4605. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.4605.
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4605 Intro: Local control of LAPC with CRT has historically demonstrated survival benefit vs. RT alone. TNF is a nonreplicating adenovirus vector delivering human tumor necrosis factor (TNF-α). Results from a phase II study with TNF in LAPC indicated a possible survival advantage. To confirm these findings, a randomized, open-label, controlled Pancreatic Cancer Trial with TNF (PACT) study was developed. Methods: The TNF arm received a 5 wk treatment of qw intratumoral inj of 4x1011 PU TNF, cont. iv 5-FU and 50.4Gy radiation. The standard of care (SOC) arm received CRT alone. Both groups received adjuvant gemcitabine(G) with the option of erlotinib(E). An IA of OS (primary efficacy endpoint) was planned after the first third (92) of the expected 276 total death events (from a total patient n=330). Nonparametric logrank of OS was planned; in addition, a lognormal model was used to account for an evident separation of the survival curves after the median. Results: 185 pts were available for OS analysis (117-TNF+SOC and 68-SOC). Survival in the TNF+SOC group demonstrated a HR of 0.753 (CI [0.494 - 1.15]) relative to SOC. Best fit parametric lognormal analysis indicated a median survival of 11.1 mo with TNF+SOC and 8.7 mo with SOC; nonparametric methods indicated a MS of 9.9 mo for both arms, with a pronounced “late effect” (75th percentile 19.4 mo with TNF+SOC and 11.8 mo with SOC). Prognostic information (G and E use, stage, etc) indicated equivalent distribution between groups. Conclusions: HR results of the OS IA indicate an encouraging trend in favor of the TNF treated group. Parametric medians may better reflect the true HR than nonparametric methods since the latter do not reflect the shape of the OS distribution. A second IA is planned after 2/3 total events. [Table: see text]
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Kallur, Kumar G., Bhatt Aditi, Gothlu Ramachandra Prashanth, Papaiah Susheela Sridhar, Subbanna Indushekar, Mallarajapatna Govindarajan, Kanakapura Ramanna Nagaraj, et al. "I-131-lipiodol therapy in local disease control and survival in patients with advanced hepatocellular carcinoma: An observational study." Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): e14721-e14721. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e14721.
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e14721 Background: In patients with Locally advanced/metastatic HCC, the median survival is 3 months. Most of these patients have altered liver functions which makes them unsuitable for any therapy. In this exploratory study we aim to test the effectiveness of I-131-lipiodol in prolonging survival in these patients. Methods: 15 patients with locally advanced HCC (unresectable) and metastatic HCC with altered liver functions (CHILDS B and C) were given I-131-lipiodol. Patients had received prior chemotherapy, prior TACE therapy, prior sorafenib and had treatment refractory progressive disease. We compared effects of I-131-Lipiodol in prolonging survival beyond three months in these patients. We performed a non parametric one sample kolmogorov Smirnov test comparing survival with I-131-lipiodol to an average 90 days survival reported in patients with advanced HCC. Results: Survival ranged from 46 to 417 days with a median survival of 144 days. However one sample test showed significant improvement in survival with I-131-lipiodol therapy compared to standard of care (z = 1.4, p = 0.04). Conclusions: I-131-lipiodol is a useful local therapy in management of patients with advanced HCC, randomized controlled trials are needed to validate its findings in adjuvant and palliative settings.
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Shaikh, Talha, Mark A. Zaki, Michael M. Dominello, Elizabeth Handorf, Andre A. Konski, Steven J. Cohen, Walter Joseph Scott, and Joshua E. Meyer. "Patterns of failure following tri-modality therapy for locally advanced esophageal cancer." Journal of Clinical Oncology 33, no. 3_suppl (January 20, 2015): 203. http://dx.doi.org/10.1200/jco.2015.33.3_suppl.203.
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203 Background: Although tri-modality therapy is an acceptable standard of care in patients with locally advanced esophageal cancer, data regarding patterns of failure is lacking. We report bi-institutional patterns of failure experience treating patients using tri-modality therapy. Methods: Following IRB approval, we retrospectively reviewed all pts who underwent chemoradiation followed by esophagectomy at two NCI-designated cancer centers from 2000-2013. Patient and treatment factors were analyzed for failure patterns. First failure sites were categorized as local, regional nodal, or distant. Statistical analysis was performed using Fisher’s exact test and non-parametric Wilcoxon rank-sum test. Results: A total of 132 patients met the inclusion criteria with a median age of 62 (range 36-80) and median follow-up of 28 months (range 4-128). The majority of patients had T3 (82%), N1 (64%), or M0/M1a (92%) disease. At the time of last follow-up there were a total of 6 (4.5%) local, 13 (10%) regional nodal, and 32 (23.5%) distant failures. Local failure was correlated with fewer lymph nodes assessed (p=0.01) and close or positive margins (p<0.01). Regional nodal failure was correlated with fewer lymph nodes assessed (p<0.01) and smaller pre-treatment tumor size (p=0.04). Distant recurrence was correlated with post-treatment nodal stage (p<0.01), peri-neural invasion (p=0.03), negative margins (p=0.02), ulceration (p=0.02), incomplete response (p<0.01), post-treatment PET SUV (p=0.05), 3D-CRT (0.053), metastatic disease at diagnosis (p<0.01) and post-treatment metastatic disease (p<0.01). No other patient, tumor, or treatment factor was correlated with treatment failure. Conclusions: Per our bi-institutional experience, patient, tumor, and treatment factors may predict for failure in patients undergoing tri-modality therapy for locally advanced esophageal cancer. Further data is needed to identify patterns of failure in these patients.
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Fernández-Hernández, Lizbeth M., Ariadna Montiel, and Mario A. Rodríguez-Meza. "Galaxy rotation curves using a non-parametric regression method: core, cuspy and fuzzy scalar field dark matter models." Monthly Notices of the Royal Astronomical Society 488, no. 4 (August 19, 2019): 5127–44. http://dx.doi.org/10.1093/mnras/stz1969.
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ABSTRACT We present a non-parametric reconstruction of the rotation curves (RCs) for 88 spiral galaxies using the LOESS (locally weighted scatterplot smoothing) + SIMEX (simulation and extrapolation) technique. In order to compare methods, we also use a parametric approach, assuming core and cuspy dark matter (DM) profiles: pseudo-isothermal (PISO), Navarro−Frenk–White (NFW), Burkert, Spano, the soliton, and two fuzzy soliton + NFW. As a result of these two approaches, a comparison of the RCs obtained is carried out by computing the distance between the central curves and the distance between the 1σ error bands. Furthermore, we perform a model selection according to two statistical criteria, the Bayesian information criterion and the value of $\chi ^2_{\rm red}$. We work with two groups. The first is a comparison between PISO, NFW, Spano and Burkert, showing that Spano is the most favoured model satisfying our selection criteria. For the second group, we select the soliton, NFW and fuzzy models, resulting in soliton as the best model. Moreover, according to the statistical tools and non-parametric reconstruction, we are able to classify galaxies as core or cuspy. Finally, using a Markov chain Monte Carlo method, for each of the DM models we compute the characteristic surface density, μDM = ρsrs, and the mass within 300 pc. We find that there is a common mass for spiral galaxies of the order of 107 M⊙, which is in agreement with results for dSph Milky Way satellites, independent of the model. This result is also consistent with our finding that there is a constant characteristic volume density of haloes. Finally, we also find that μDM is not constant, which is in tension with the literature.
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Jeon, S. O., J. Bunge, T. Stoeck, K. J. A. Barger, S. H. Hong, and S. S. Epstein. "Synthetic Statistical Approach Reveals a High Degree of Richness of Microbial Eukaryotes in an Anoxic Water Column." Applied and Environmental Microbiology 72, no. 10 (October 2006): 6578–83. http://dx.doi.org/10.1128/aem.00787-06.
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ABSTRACT Molecular surveys suggest that communities of microbial eukaryotes are remarkably rich, because even large clone libraries seem to capture only a minority of species. This provides a qualitative picture of protistan richness but does not measure its real extent either locally or globally. Statistical analysis can estimate a community's richness, but the specific methods used to date are not always well grounded in statistical theory. Here we study a large protistan molecular survey from an anoxic water column in the Cariaco Basin (Caribbean Sea). We group individual 18S rRNA gene sequences into operational taxonomic units (OTUs) using different cutoff values for sequence similarity (99 to 50%) and systematically apply parametric models and nonparametric estimators to the OTU frequency data to estimate the total protistan diversity. The parametric models provided statistically sound estimates of protistan richness, with biologically meaningful standard errors, maximal data usage, and extensive model diagnostics and were preferable to the available nonparametric tools. Our clone library exceeded 700 clones but still covered only a minority of species and less than half of the larger protistan clades. Our estimates of total protistan richness portray the target community as very rich at all OTU levels, with hundreds of different populations apparently co-occurring in the small (3-liter) volume of our sample, as well as dozens of clades of the highest taxonomic order. These estimates are among the first for microbial eukaryotes that are obtained using state-of-the-art statistical methods and can serve as benchmark numbers for the local diversity of protists.
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Debbabi, Imad Eddine, Mohamed Saddek Remadna, and Ahmad Safuan A. Rashid. "Numerical Modeling of Horizontally Layered Geosynthetic Reinforced Encased Stone Columns Supporting Embankment on Sabkha Soil." International Journal of Engineering Research in Africa 52 (January 2021): 164–78. http://dx.doi.org/10.4028/www.scientific.net/jera.52.164.
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The present research work is concerned with the construction of road embankments on a Sabkha soil in Algeria. This soil is not only soft and very humid during the flooding seasons but also has frequent small areas of very soft soil which are called locally weak zones (LWZ) in the context of this study. LWZ are characterized by low strength and high compressibility. Two-dimensional axisymmetric analyses were carried out using PLAXIS 2D 2017. The study demonstrated that ordinary stone columns (OSC) are ineffective given the nature of these soils due to the excessive bulging caused by the lack of lateral pressure. On the other hand, the reinforced stone columns with external and internal reinforcements called as vertical encasement and horizontal strips (VESC+HRSC) are one of the best improvement methods of locally weak zones (LWZ), especially to increase the stability of embankment on the highway, namely, a much reduced bulging and a reasonable settlement, so that it is possible to build safe and very high embankments (indeed, numerical results showed for a (VESC+HRSC) combination, a vertical settlement of 0.74 m and a lateral deformation of 20.02 mm vs. 1.56 m and 221.16 mm for an OSC). Besides, an extensive parametric study was conducted to investigate the effect of the spacing of the horizontal reinforcing strips and of the column reinforced length. The influence of stone column diameter, depth of locally weak zone, and the effective stiffness of the geosynthetic, on the performance of the (RSC) - embankment composite were also investigated. The computational results are presented in the form of tables and graphs, and compared with previous published results available in the literature.
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Lang, Jin Yi, Zixuan Fan, Peng Xu, Mei Feng, and Weidong Wang. "3D HDR intracavitary brachytherapy combined with complementary applicator-guided external beam radiotherapy for 338 patients with stage IIB-IIIB uterine cervical cancer: A single-center phase II prospective study with long-term follow-up." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): 5530. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.5530.
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5530 Background: For uterine cervical cancer (UCC) patients with asymmetric parametric lesions, 3D HDR-intracavitary brachytherapy (HDR-ICBT) could not cover all the lesions, resulting in residual lesion and treatment failure. To settle this problem, a novel treatment modal of 3D HDR-ICBT combined with complementary applicator-guided external beam radiotherapy (EBRT) was used for UCC patients with stage IIB-IIIB in present study. Methods: Between June 2010 and June 2015, 338 patients with locally advanced cervical cancer (International Federation of Gynecology and Obstetrics stage IIB-IIIB) were treated with concurrent chemoradiotherapy. Imaged guided IMRT was used for external beam radiotherapy, 45Gy/25f. The chemotherapy was weekly cisplatin (40mg/m2). Four fractions of 3D HDR-ICBT combined with complementary applicator-guided external beam radiotherapy were used. The prescribed dose for HR-CTV and IR-CTV was 7Gy (D90) and 5Gy (D90). Dose constraints for organs at risk were D2cc <70 Gy for rectum, and D2cc<90 Gy for bladder in terms of equivalent total dose in 2 Gy fractions as GEC-ESTRO recommendations. Results: Median follow-up was 64 months (11–71 months). The D90 of GTV, HR-CTV, and IR-CTV in all cases were 93.4 (85.1-107.8) Gy, 86.4 (79.9-91.3) Gy and 72.3 (70.8-75.2) Gy, respectively. The D2CC of bladder, rectum and sigmoid were 74.3Gy、65.5Gy and 64.1Gy, respectively. 5-year LRC, DFS, and OS was 90.8%, 84.1% and 80.8%, respectively. Treatment was well tolerated. The grade ≥3 genitourinary and gastrointestinal acute and late toxicities were 2.1% and 5.2%, respectively. Conclusions: The combination of HDR-ICBT with an applicator-guided IMRT is feasible for uterine cervical cancer patients with asymmetric parametric lesions. Further study is needed to determine whether this treatment modal could be used to replace the invasive interstitial brachytherapy (ISBT) in the cases of locally advanced cervical cancer where HR-CTV coverage cannot be obtained with ICBT.
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Thang, Do Quang. "Deriving formulations for forecasting the ultimate strength of locally dented ring-stiffened cylinders under combined axial compression and radial pressure loads." Science and Technology Development Journal 23, no. 3 (September 2, 2020): 640–54. http://dx.doi.org/10.32508/stdj.v23i3.2412.
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Introduction: This paper focuses on the derived equations to evaluate the ultimate strength of ring-stiffened cylinders with local denting damage under combined loadings. The damage generation scenarios in this research are representing the collision accidents of offshore stiffened cylinders with supply ships.
Methods: Numerical analysis of structures are performed using Abaqus software after validation against the experiments from the authors. The responses from seventeen cylinder specimens are analyzed to develop the numerical methods.
Results: Good accuracy results were achieved when comparing the test results and the simulation results. Parametric studies are then performed on design examples of ring-stiffened cylinders when considering both intact and damaged conditions for assessing the reduction factor. Then, the novel simple design equations to assess the residual strength of ring-stiffened cylinders after ship collision are derived based on the regression analysis. These equations have good accuracy with mean value Xm (Uncertainty modeling factor) around 1.0 and together with COV (Coefficient of Variation) lower than 5.3%.
Conclusion: The accuracy and reliability of the derived equations are validated by comparing it with the existing test data in open access. It is concluded that the proposed equations have high accuracy and reliability, and convenient application for the purpose of checking the residual strength of dented offshore cylinder under ship collisions.
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Fernandes, Annemarie Therese, Jonathan Taylor Whaley, Kevin Teo, John Peter Plastaras, James M. Metz, Rodolfo F. Perini, Daniel A. Pryma, and Smith Apisarnthanarax. "Predicting outcomes in locally advanced rectal cancer using pretreatment FDG-PET imaging." Journal of Clinical Oncology 31, no. 4_suppl (February 1, 2013): 495. http://dx.doi.org/10.1200/jco.2013.31.4_suppl.495.
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495 Background: FDG-PET/CT imaging has been shown to have clinical utility in the management of rectal cancers. The purpose of this study was to investigate multiple FDG-PET/CT parameters to predict for outcome after neoadjuvant chemoradiation (CRT) in patients (pts) with locally advanced rectal adenocarcinoma. Methods: We retrospectively evaluated pts with locally-advanced (T2-4, N0-2, M0) rectal adenocarcinoma treated with neoadjuvant CRT who received FDG-PET/CT scans for radiation therapy planning. We evaluated the impact of SUVmax and metabolic tumor volume (MTV, determined by using PET Edge MimVista), as well as dual-time point PET parameters of retention index (RI, difference in SUVmax between the two PET scans) and RI/time. Endpoints of pathologic complete response (pCR), tumor grade, margin status and pathologic downstaging were assessed using t-test, ANOVA or non-parametric analysis when appropriate. Progression-free survival (PFS) and overall survival (OS) were assessed using Kaplan Meier estimates. Results: Of the 28 consecutive pts with FDG-PET/CT planning scans identified, 25 pts underwent surgical resection. All patients received a 5-FU based concurrent chemotherapy regimen with RT (median RT dose: 50.4 Gy). Median follow-up was 21 months. The median MTV was 45 cc. Compared to pts with a MTV>45 cc, pts with a MTV <45 cc had improved PFS (2-yr PFS: 86% vs. 60%, p=0.04) and improved OS (2-yr OS: 100% vs. 51%, p=0.01). The correlation between MTV and T-stage was not statistically significant (23% of pts with MTV>45 had T4 tumors vs. 0% of pts with MTV<45, p=0.17). MTV did not correlate with the other endpoints (pCR, tumor grade, margin status, pathologic downstaging). SUVmax did not correlate with any of the identified endpoints. Of the patients with dual-time point PET/CT scans (N=19), RI and RI/time did not correlate with any of the identified endpoints. Conclusions: Pretreatment MTV correlates with PFS and OS in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiation. For pts with large MTVs, more aggressive treatment approaches should be considered. Dual-time point FDG-PET imaging does not appear to add clinical value in this patient population.
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Grosser, Malte, Susanne Gellißen, Patrick Borchert, Jan Sedlacik, Jawed Nawabi, Jens Fiehler, and Nils D. Forkert. "Localized prediction of tissue outcome in acute ischemic stroke patients using diffusion- and perfusion-weighted MRI datasets." PLOS ONE 15, no. 11 (November 5, 2020): e0241917. http://dx.doi.org/10.1371/journal.pone.0241917.
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Background An accurate prediction of tissue outcome in acute ischemic stroke patients is of high interest for treatment decision making. To date, various machine learning models have been proposed that combine multi-parametric imaging data for this purpose. However, most of these machine learning models were trained using voxel information extracted from the whole brain, without taking differences in susceptibility to ischemia into account that exist between brain regions. The aim of this study was to develop and evaluate a local tissue outcome prediction approach, which makes predictions using locally trained machine learning models and thus accounts for regional differences. Material and methods Multi-parametric MRI data from 99 acute ischemic stroke patients were used for the development and evaluation of the local tissue outcome prediction approach. Diffusion (ADC) and perfusion parameter maps (CBF, CBV, MTT, Tmax) and corresponding follow-up lesion masks for each patient were registered to the MNI brain atlas. Logistic regression (LR) and random forest (RF) models were trained employing a local approach, which makes predictions using models individually trained for each specific voxel position using the corresponding local data. A global approach, which uses a single model trained using all voxels of the brain, was used for comparison. Tissue outcome predictions resulting from the global and local RF and LR models, as well as a combined (hybrid) approach were quantitatively evaluated and compared using the area under the receiver operating characteristic curve (ROC AUC), the Dice coefficient, and the sensitivity and specificity metrics. Results Statistical analysis revealed the highest ROC AUC and Dice values for the hybrid approach. With 0.872 (ROC AUC; LR) and 0.353 (Dice; RF), these values were significantly higher (p < 0.01) than the values of the two other approaches. In addition, the local approach achieved the highest sensitivity of 0.448 (LR). Overall, the hybrid approach was only outperformed in sensitivity (LR) by the local approach and in specificity by both other approaches. However, in these cases the effect sizes were comparatively small. Conclusion The results of this study suggest that using locally trained machine learning models can lead to better lesion outcome prediction results compared to a single global machine learning model trained using all voxel information independent of the location in the brain.
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Žukovič, Milan, and Dionissios T. Hristopulos. "Ising Model for Interpolation of Spatial Data on Regular Grids." Entropy 23, no. 10 (September 28, 2021): 1270. http://dx.doi.org/10.3390/e23101270.
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We apply the Ising model with nearest-neighbor correlations (INNC) in the problem of interpolation of spatially correlated data on regular grids. The correlations are captured by short-range interactions between “Ising spins”. The INNC algorithm can be used with label data (classification) as well as discrete and continuous real-valued data (regression). In the regression problem, INNC approximates continuous variables by means of a user-specified number of classes. INNC predicts the class identity at unmeasured points by using the Monte Carlo simulation conditioned on the observed data (partial sample). The algorithm locally respects the sample values and globally aims to minimize the deviation between an energy measure of the partial sample and that of the entire grid. INNC is non-parametric and, thus, is suitable for non-Gaussian data. The method is found to be very competitive with respect to interpolation accuracy and computational efficiency compared to some standard methods. Thus, this method provides a useful tool for filling gaps in gridded data such as satellite images.
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Gu, Jiaying, Roger Koenker, and Stanislav Volgushev. "TESTING FOR HOMOGENEITY IN MIXTURE MODELS." Econometric Theory 34, no. 4 (July 24, 2017): 850–95. http://dx.doi.org/10.1017/s0266466617000299.
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Statistical models of unobserved heterogeneity are typically formalized as mixtures of simple parametric models and interest naturally focuses on testing for homogeneity versus general mixture alternatives. Many tests of this type can be interpreted as C(α) tests, as in Neyman (1959), and shown to be locally asymptotically optimal. These C(α) tests will be contrasted with a new approach to likelihood ratio testing for general mixture models. The latter tests are based on estimation of general nonparametric mixing distribution with the Kiefer and Wolfowitz (1956) maximum likelihood estimator. Recent developments in convex optimization have dramatically improved upon earlier EM methods for computation of these estimators, and recent results on the large sample behavior of likelihood ratios involving such estimators yield a tractable form of asymptotic inference. Improvement in computation efficiency also facilitates the use of a bootstrap method to determine critical values that are shown to work better than the asymptotic critical values in finite samples. Consistency of the bootstrap procedure is also formally established. We compare performance of the two approaches identifying circumstances in which each is preferred.
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Berchialla, Paola, Veronica Sciannameo, Sara Urru, Corrado Lanera, Danila Azzolina, Dario Gregori, and Ileana Baldi. "Adjustment for Baseline Covariates to Increase Efficiency in RCTs with Binary Endpoint: A Comparison of Bayesian and Frequentist Approaches." International Journal of Environmental Research and Public Health 18, no. 15 (July 22, 2021): 7758. http://dx.doi.org/10.3390/ijerph18157758.
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Background: In a randomized controlled trial (RCT) with binary outcome the estimate of the marginal treatment effect can be biased by prognostic baseline covariates adjustment. Methods that target the marginal odds ratio, allowing for improved precision and power, have been developed. Methods: The performance of different estimators for the treatment effect in the frequentist (targeted maximum likelihood estimator, inverse-probability-of-treatment weighting, parametric G-computation, and the semiparametric locally efficient estimator) and Bayesian (model averaging), adjustment for confounding, and generalized Bayesian causal effect estimation frameworks are assessed and compared in a simulation study under different scenarios. The use of these estimators is illustrated on an RCT in type II diabetes. Results: Model mis-specification does not increase the bias. The approaches that are not doubly robust have increased standard error (SE) under the scenario of mis-specification of the treatment model. The Bayesian estimators showed a higher type II error than frequentist estimators if noisy covariates are included in the treatment model. Conclusions: Adjusting for prognostic baseline covariates in the analysis of RCTs can have more power than intention-to-treat based tests. However, for some classes of model, when the regression model is mis-specified, inflated type I error and potential bias on treatment effect estimate may arise.
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Cui, Y., and J. Hannig. "Nonparametric generalized fiducial inference for survival functions under censoring." Biometrika 106, no. 3 (June 9, 2019): 501–18. http://dx.doi.org/10.1093/biomet/asz016.
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Summary Since the introduction of fiducial inference by Fisher in the 1930s, its application has been largely confined to relatively simple, parametric problems. In this paper, we present what might be the first time fiducial inference is systematically applied to estimation of a nonparametric survival function under right censoring. We find that the resulting fiducial distribution gives rise to surprisingly good statistical procedures applicable to both one-sample and two-sample problems. In particular, we use the fiducial distribution of a survival function to construct pointwise and curvewise confidence intervals for the survival function, and propose tests based on the curvewise confidence interval. We establish a functional Bernstein–von Mises theorem, and perform thorough simulation studies in scenarios with different levels of censoring. The proposed fiducial-based confidence intervals maintain coverage in situations where asymptotic methods often have substantial coverage problems. Furthermore, the average length of the proposed confidence intervals is often shorter than the length of confidence intervals for competing methods that maintain coverage. Finally, the proposed fiducial test is more powerful than various types of log-rank tests and sup log-rank tests in some scenarios. We illustrate the proposed fiducial test by comparing chemotherapy against chemotherapy combined with radiotherapy, using data from the treatment of locally unresectable gastric cancer.
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Mkrtchyan, Liana, Andrey Kaprin, Sergey Ivanov, G. Kulieva, and Lyudmila Krikunova. "THE EFFECTIVENESS OF TREATMENT FOR LOCALLY ADVANCED CERVICAL CANCER DEPENDING ON THE FACTORS OF PROGNOSIS." Problems in oncology 65, no. 4 (April 1, 2019): 584–89. http://dx.doi.org/10.37469/0507-3758-2019-65-4-584-589.
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Purpose: to estimate the efficiency of the concurrent chemoradiotherapy (CRT) and radiotherapy (RT) alone for patients with the locally advanced cervical cancer (CC) taking into account prognostic factors. Material and methods: The research included 335 patients with morphologically verified CC of the П-Ш stage on FIGO: 150 patients underwent RT (group 1): 185 patients - CRT with cisplatin and 5-fluorouracil (group 2). Patients in the group 1 were significantly older than patients of the group 2. The disease of the Stage III, parametric variant of the spread of the tumor, as well as metastatic lesions of the pelvic lymph nodes occurred more frequently in the group 2. Results: In the group 1 complete response to treatment occurred in 98 cases (52.9%), while in the group 2 demonstrated - 64 (42.7%) patients (p < 0.01). Radioepithelitis of Grade 1 and 2 occurred more frequently in patients underwent CRT in this group haematologic and gastrointestinal toxicity was moderate and severe (p = 0.01). Study of late treatment outcomes with method Kaplan-Meyer demonstrated tendency to increase in indicators on the term of 5 years: the overall survival was 69.7±4.6% and 77.1±3.9 - in the group 1 and 2 respectively; the disease-free survival (DFS) was 69.5±4.5% and 75.1±4.1% - respectively; DFS at the II stage was 81.1±5.3% and 90.9±3.9% - respectively; at the III stage it was 56.4±7.3 and 66.1±5.6% respectively (p > 0.05). The variables that were found to be of independent significance for progression-free survival by multivariate analysis were stage of a disease, type of distribution and a morphological form of a tumor (p < 0.05); the method of treatment was not predictive in the probability of an adverse clinical outcome of locally advanced CC. Conclusion: RT is an adequate method of treatment for a part of patients with II-III stages of CC of older patients with associated diseases, without reducing quality of life and also results of treatment.
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Franz, A., B. Fischer, and S. Kabus. "Spatially Varying Elasticity in Image Registration." Methods of Information in Medicine 46, no. 03 (2007): 287–91. http://dx.doi.org/10.1160/me9045.
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Summary Objectives: In this paper we are concerned with elastic image registration. Usually, elastic approaches assume constant material parameters and result in a smooth displacement field. However, a constant choice has its shortcomings for images with varying elastic properties, like bones and soft tissue. The proposed method allows forspatially varying material properties. Methods: The proposed variational registration scheme is based on a segmentation of the template image. Individual material properties can be assigned to each segmented region. The proposed variable elastic regulariser leads to a displacement field which is adapted to the locally chosen material properties. Results: The capability of this approach is demonstrated by a synthetic and by real-life examples in two dimensions. For all examples the proposed method is compared to a conventional scheme where the material parameters are constants in the entire image domain. Conclusions: A method for non-parametric registration which supports spatially varying elastic properties such as (in)compressibility or Young’s modulus in certain image regions is proposed. It allows for registration results to be more realistic compared to conventional approaches. Also, for a particular structure, an approximated preservation of volume or shape can be achieved.
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Khazaal, Yasser, Fares Zine El Abiddine, Louise Penzenstadler, Djamal Berbiche, Ghada Bteich, Saeideh Valizadeh-Haghi, Lucien Rochat, Sophia Achab, Riaz Khan, and Anne Chatton. "Evaluation of the Psychometric Properties of the Arab Compulsive Internet Use Scale (CIUS) by Item Response Theory Modeling (IRT)." International Journal of Environmental Research and Public Health 19, no. 19 (September 24, 2022): 12099. http://dx.doi.org/10.3390/ijerph191912099.
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Introduction: The psychometric properties of the Arab translation of the Compulsive Internet Use Scale (CIUS) have been previously studied by confirmatory factor analysis (CFA) with AMOS software using the asymptotically distribution-free (ADF) estimator. Unidimensionality has been achieved at the cost of correlating several item variance errors. However, several reviews of SEM software packages and estimation methods indicate that the option of robust standard errors is not present in the AMOS package and that ADF estimation may yield biased parameter estimates. We therefore explored a second analysis through item response theory (IRT) using the parametric graded response model (GRM) and the marginal maximum likelihood (MML) estimation method embedded in the LTM package of R software. Differential item functioning (DIF) or item bias across subpopulations was also explored within IRT framework as different samples were investigated. The objective of the current study is to (1) analyze the Arab CIUS scale with IRT, (2) investigate DIF in three samples, and (3) contribute to the ongoing debate on Internet-use-related addictive behaviors using the CIUS items as a proxy. Methods: We assessed three samples of people, one in Algeria and two in Lebanon, with a total of 1520 participants. Results: Almost three out of every five items were highly related to the latent construct. However, the unidimensionality hypothesis was not supported. Furthermore, besides being locally dependent, the scale may be weakened by DIF across geographic regions. Some of the CIUS items related to increasing priority, impaired control, continued use despite harm, and functional impairment as well as withdrawal and coping showed good discriminative capabilities. Those items were endorsed more frequently than other CIUS items in people with higher levels of addictive Internet use. Conclusions: Contrary to earlier ADF estimation findings, unidimensionality of the CIUS scale was not supported by IRT parametric GRM in a large sample of Arab speaking participants. The results may be helpful for scale revision. By proxy, the study contributes to testing the validity of addiction criteria applied to Internet use related-addictive behaviors.
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Stavrinos, Panayiotis, and Sergiu I. Vacaru. "Broken Scale Invariance, Gravity Mass, and Dark Energy inModified Einstein Gravity with Two Measure Finsler like Variables." Universe 7, no. 4 (April 3, 2021): 89. http://dx.doi.org/10.3390/universe7040089.
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We study new classes of generic off-diagonal and diagonal cosmological solutions for effective Einstein equations in modified gravity theories (MGTs), with modified dispersion relations (MDRs), and encoding possible violations of (local) Lorentz invariance (LIVs). Such MGTs are constructed for actions and Lagrange densities with two non-Riemannian volume forms (similar to two measure theories (TMTs)) and associated bimetric and/or biconnection geometric structures. For conventional nonholonomic 2 + 2 splitting, we can always describe such models in Finsler-like variables, which is important for elaborating geometric methods of constructing exact and parametric solutions. Examples of such Finsler two-measure formulations of general relativity (GR) and MGTs are considered for Lorentz manifolds and their (co) tangent bundles and abbreviated as FTMT. Generic off-diagonal metrics solving gravitational field equations in FTMTs are determined by generating functions, effective sources and integration constants, and characterized by nonholonomic frame torsion effects. By restricting the class of integration functions, we can extract torsionless and/or diagonal configurations and model emergent cosmological theories with square scalar curvature, R2, when the global Weyl-scale symmetry is broken via nonlinear dynamical interactions with nonholonomic constraints. In the physical Einstein–Finsler frame, the constructions involve: (i) nonlinear re-parametrization symmetries of the generating functions and effective sources; (ii) effective potentials for the scalar field with possible two flat regions, which allows for a unified description of locally anisotropic and/or isotropic early universe inflation related to acceleration cosmology and dark energy; (iii) there are “emergent universes” described by off-diagonal and diagonal solutions for certain nonholonomic phases and parametric cosmological evolution resulting in various inflationary phases; (iv) we can reproduce massive gravity effects in two-measure theories. Finally, we study a reconstructing procedure for reproducing off-diagonal FTMT and massive gravity cosmological models as effective Einstein gravity or Einstein–Finsler theories.
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Gunarathne, Sajaan Praveena, Nuwan Darshana Wickramasinghe, Thilini Chanchala Agampodi, Indika Ruwan Prasanna, and Suneth Buddhika Agampodi. "Economic burden of out-of-pocket expenditure, productivity cost during pregnancy and COVID-19 impact on household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka; A study protocol." F1000Research 10 (July 30, 2021): 700. http://dx.doi.org/10.12688/f1000research.53320.1.
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Background: Investigating the out-of-pocket expenditure (OOPE) associated with maternal health is important since OOPE directly affects the affordability of health services. Global evidence suggests the importance of capturing the productivity cost during pregnancy in terms of absenteeism and presenteeism. Furthermore, the impact of the ongoing COVID-19 pandemic on the household economy needs to be further evaluated as pregnant women are one of the most vulnerable groups. This study aims at determining the economic burden of OOPE, productivity cost, and COVID-19 impact on pregnant women's household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka. Methods: The study setting is all 22 Medical Officer of Health (MOH) areas in Anuradhapura district, Sri Lanka. The study has three components; a follow-up study of a cohort of pregnant women to assess the magnitude and associated factors of OOPE and to assess the productivity cost (Component 1), a qualitative case study to explore the impact and causes of the OOPE under free health services (Component 2) and a cross-sectional study to describe the effects of COVID-19 outbreak on household economy (Component 3). The study samples consist of 1,393 and 1,460 participants for components one and three, respectively, and 25 pregnant women will be recruited for component two. The data will be analyzed using descriptive, parametric, and non-parametric statistics for the first and third components and thematic analysis for the second component. Discussion: With the lack of evidence on OOPE, productivity loss/cost in terms of maternal health, and COVID-19 impact on household economy in Sri Lanka, the evidence generated from this study would be valuable for policymakers, health care administrators, and health care practitioners globally, regionally, and locally to plan for future measures for reducing the OOPE, productivity loss/cost, and minimizing the economic hardship of the COVID-19 outbreak during pregnancy.
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Gunarathne, Sajaan Praveena, Nuwan Darshana Wickramasinghe, Thilini Chanchala Agampodi, Indika Ruwan Prasanna, and Suneth Buddhika Agampodi. "Economic burden of out-of-pocket expenditure, productivity cost during pregnancy and COVID-19 impact on household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka; A study protocol." F1000Research 10 (January 28, 2022): 700. http://dx.doi.org/10.12688/f1000research.53320.2.
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Background: Investigating the out-of-pocket expenditure (OOPE) associated with maternal health is important since OOPE directly affects the affordability of health services. Global evidence suggests the importance of capturing the productivity cost during pregnancy in terms of absenteeism and presenteeism. Furthermore, the impact of the ongoing COVID-19 pandemic on the household economy needs to be further evaluated as pregnant women are one of the most vulnerable groups. This study aims at determining the economic burden of OOPE, productivity cost, and COVID-19 impact on pregnant women's household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka. Methods: The study setting is all 22 Medical Officer of Health (MOH) areas in Anuradhapura district, Sri Lanka. The study has three components; a follow-up study of a cohort of pregnant women to assess the magnitude and associated factors of OOPE and to assess the productivity cost (Component 1), a qualitative case study to explore the impact and causes of the OOPE under free health services (Component 2) and a cross-sectional study to describe the effects of COVID-19 outbreak on household economy (Component 3). The study samples consist of 1,393 and 1,460 participants for components one and three, respectively, and 25 pregnant women will be recruited for component two. The data will be analyzed using descriptive, parametric, and non-parametric statistics for the first and third components and thematic analysis for the second component. Discussion: With the lack of evidence on OOPE, productivity loss/cost in terms of maternal health, and COVID-19 impact on household economy in Sri Lanka, the evidence generated from this study would be valuable for policymakers, health care administrators, and health care practitioners globally, regionally, and locally to plan for future measures for reducing the OOPE, productivity loss/cost, and minimizing the economic hardship of the COVID-19 outbreak during pregnancy.
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Gunarathne, Sajaan Praveena, Nuwan Darshana Wickramasinghe, Thilini Chanchala Agampodi, Indika Ruwan Prasanna, and Suneth Buddhika Agampodi. "Economic burden of out-of-pocket expenditure, productivity cost during pregnancy and COVID-19 impact on household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka; A study protocol." F1000Research 10 (March 4, 2022): 700. http://dx.doi.org/10.12688/f1000research.53320.3.
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Background: Investigating the out-of-pocket expenditure (OOPE) associated with maternal health is important since OOPE directly affects the affordability of health services. Global evidence suggests the importance of capturing the productivity cost during pregnancy in terms of absenteeism and presenteeism. Furthermore, the impact of the ongoing COVID-19 pandemic on the household economy needs to be further evaluated as pregnant women are one of the most vulnerable groups. This study aims at determining the economic burden of OOPE, productivity cost, and COVID-19 impact on pregnant women's household economy in a cohort of pregnant women in Anuradhapura District, Sri Lanka. Methods: The study setting is all 22 Medical Officer of Health (MOH) areas in Anuradhapura district, Sri Lanka. The study has three components; a follow-up study of a cohort of pregnant women to assess the magnitude and associated factors of OOPE and to assess the productivity cost (Component 1), a qualitative case study to explore the impact and causes of the OOPE under free health services (Component 2) and a cross-sectional study to describe the effects of COVID-19 outbreak on household economy (Component 3). The study samples consist of 1,573 and 1,460 participants for components one and three, respectively, and 25 pregnant women will be recruited for component two. The data will be analyzed using descriptive, parametric, and non-parametric statistics for the first and third components and thematic analysis for the second component. Discussion: With the lack of evidence on OOPE, productivity loss/cost in terms of maternal health, and COVID-19 impact on household economy in Sri Lanka, the evidence generated from this study would be valuable for policymakers, health care administrators, and health care practitioners globally, regionally, and locally to plan for future measures for reducing the OOPE, productivity loss/cost, and minimizing the economic hardship of the COVID-19 outbreak during pregnancy.
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Zhong, Yichen, Yizhen Lai, Haojie Li, Rachael Batteson, Yang Meng, Tara L. Frenkl, James Luke Godwin, and Guru Sonpavde. "Cost-effectiveness of pembrolizumab as second-line therapy for the treatment of locally advanced or metastatic urothelial carcinoma in the United States." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e16010-e16010. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e16010.
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e16010 Background: Pembrolizumab is approved by the US Food and Drug Administration for the treatment of locally advanced or metastatic urothelial carcinoma (mUC) following platinum-based chemotherapy, based on results from KEYNOTE-045. In this randomized phase 3 trial, pembrolizumab significantly prolonged overall survival (OS) vs. chemotherapy in mUC patients (cut-off: Oct 26, 2017). The current analysis evaluates the cost-effectiveness of pembrolizumab vs. standard-of-care chemotherapy (docetaxel or paclitaxel) as second-line (2L) treatment for mUC, from a US payer perspective. Methods: We developed a partitioned-survival model to measure the costs and effectiveness over a 20-year time horizon to capture long-term costs and benefits from the treatments. Clinical efficacy, time on treatment, safety and utility data were derived from KEYNOTE-045. OS and progression-free survival were extrapolated beyond the trial period using piecewise models, i.e., Kaplan-Meier data followed by parametric function. Costs (in 2018 $US) for drug acquisition/administration, disease monitoring, adverse events management and terminal care were included. Costs and outcomes were discounted at 3% per year. Deterministic and probabilistic sensitivity analyses were conducted to assess the robustness of the results. Results: Pembrolizumab resulted in a mean gain of 1.33 life years (LYs) and 1.14 quality-adjusted life-years (QALYs) at an incremental cost of $103,861 vs. chemotherapy. The incremental cost-effectiveness ratios were $91,103/QALY and $78,254/LY. Key drivers of cost-effectiveness were extrapolation methods for OS data, time horizon and utility values. Pembrolizumab had a 72% or 100% probability of being cost-effective vs. chemotherapy at a $100,000 or $150,000 willingness-to-pay threshold, respectively. Conclusions: Pembrolizumab appears to be cost-effective vs. docetaxel or paclitaxel monotherapy as 2L mUC therapy when accounting for durable survival seen in a subset of patients receiving pembrolizumab. The model was established based on robust estimates, with key clinical endpoints directly drawn or derived from patient level data in KEYNOTE-045.
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Visser, Denise, Emma E. Wolters, Sander C. J. Verfaillie, Emma M. Coomans, Tessa Timmers, Hayel Tuncel, Juhan Reimand, et al. "Tau pathology and relative cerebral blood flow are independently associated with cognition in Alzheimer’s disease." European Journal of Nuclear Medicine and Molecular Imaging 47, no. 13 (May 27, 2020): 3165–75. http://dx.doi.org/10.1007/s00259-020-04831-w.
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Abstract Purpose We aimed to investigate associations between tau pathology and relative cerebral blood flow (rCBF), and their relationship with cognition in Alzheimer’s disease (AD), by using a single dynamic [18F]flortaucipir positron emission tomography (PET) scan. Methods Seventy-one subjects with AD (66 ± 8 years, mini-mental state examination (MMSE) 23 ± 4) underwent a dynamic 130-min [18F]flortaucipir PET scan. Cognitive assessment consisted of composite scores of four cognitive domains. For tau pathology and rCBF, receptor parametric mapping (cerebellar gray matter reference region) was used to create uncorrected and partial volume-corrected parametric images of non-displaceable binding potential (BPND) and R1, respectively. (Voxel-wise) linear regressions were used to investigate associations between BPND and/or R1 and cognition. Results Higher [18F]flortaucipir BPND was associated with lower R1 in the lateral temporal, parietal and occipital regions. Higher medial temporal BPND was associated with worse memory, and higher lateral temporal BPND with worse executive functioning and language. Higher parietal BPND was associated with worse executive functioning, language and attention, and higher occipital BPND with lower cognitive scores across all domains. Higher frontal BPND was associated with worse executive function and attention. For [18F]flortaucipir R1, lower values in the lateral temporal and parietal ROIs were associated with worse executive functioning, language and attention, and lower occipital R1 with lower language and attention scores. When [18F]flortaucipir BPND and R1 were modelled simultaneously, associations between lower R1 in the lateral temporal ROI and worse attention remained, as well as for lower parietal R1 and worse executive functioning and attention. Conclusion Tau pathology was associated with locally reduced rCBF. Tau pathology and low rCBF were both independently associated with worse cognitive performance. For tau pathology, these associations spanned widespread neocortex, while for rCBF, independent associations were restricted to lateral temporal and parietal regions and the executive functioning and attention domains. These findings indicate that each biomarker may independently contribute to cognitive impairment in AD.
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Domina, Olena. "Solution of the compromise optimization problem of network graphics on the criteria of uniform personnel loading and distribution of funds." Technology audit and production reserves 1, no. 4(57) (February 26, 2021): 14–21. http://dx.doi.org/10.15587/2706-5448.2021.225527.
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The object of research is a model network schedule for performing a complex of operations. One of the most problematic areas is the lack of a unified procedure that allows finding a solution to the problem of compromise optimization, for which the optimization criteria can have a different nature of the influence of input variables on them. In this study, such criteria are the criteria for the uniformity of the workload of personnel and the distribution of funds. Two alternative cases are considered: with monthly planning and with quarterly planning of allocation of funds and staff load. The methods of mathematical planning of the experiment and the ridge analysis of the response surface are used. The peculiarities of the proposed procedure for solving the problem of compromise optimization are its versatility and the possibility of visualization in one-dimensional form – the dependence of each of the alternative criteria on one parameter describing the constraints. The solution itself is found as the point of intersection of equally labeled ridge lines, which are curves that describe the locally optimal values of the output variables. The proposed procedure, despite the fact that it is performed only on a model network diagram, can be used to solve the trade-off optimization problem on arbitrary network graphs. This is due to the fact that the combination of locally optimal solutions in a parametric form on one graph allows visualizing all solutions to the problem. The results obtained at the same time make it possible to select early dates for the start of operations in such a way that, as much as possible, take into account possible difficulties due to the formation of bottlenecks at certain stages of the project. The latter may be due to the fact that for the timely execution of some operation, it may be necessary to combine two criteria, despite the fact that the possible costs may turn out to be more calculated and estimated as optimal.
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Bhattacharyya, Gouri Shankar, Hemant Malhotra, K. Govind Babu, Amish Vora, and Tapati Barman. "Disorders of taste (dysgeusia) in head and neck cancer patients on concomitant CT/RT." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): e18199-e18199. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e18199.
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e18199 Background: Head & Neck cancer is a major problem in India and developing countries related to use of tobacco. Locally advanced oral cavity cancers form a majority of cancers of this region. Common method of treatment of this region is to use concomitant radiation with chemotherapy and/or biotherapy. One of the side effects of regional treatment is loss of taste or dysfunction of taste. This although common has not been properly evaluated or reported. Its impact although conceivable is not used in dietary modifications or tailoring treatment. Methods: Taste discrimination was assessed using high medium and low concentration of sweet salty sour and bitter tasting solution. Cross-sectional observational study was designed to describe the prevalence of taste dysfunction in a group of Head & Neck cancer survivors with oral cancers. Survivors were required to be disease free for at least 3 months symptomatically and imaging wise. Only patients found fit on cognitive assessments as well as capable of comprehending language were asked to fill a simple seven question graded chart. Results: Non parametric approach was done for taste score. Descriptive statistics were used for taste scores and self-reported taste changes. 90 patients were included. Age group 49y – 80y. 58 patients were above the age of 65y. 1/3rd of the patients were females. All patients were locally advanced patient and the commonest site was oral cavity and oro-pharynx – 80%. Participants performed poorly on the taste test. The commonest disturbance in taste was in sweet and sour. 20% of patients had bitter and metallic taste in mouth. 1/3rd of patients had no taste. Patients with maintained taste did not lose weight. Long term taste dysfunction persisted in about 30% of patients. Conclusions: Head & Neck cancer survivors have taste dysfunctions. Taste recognition is demonstrated at low and high concentrations as well as persistent bitter and metallic phantom taste. It may persist for long periods of time. Recognizing this problem is important so the clinicians can help survivor scope with the problem.
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Bui, Long V., Ha T. Nguyen, Hagai Levine, Ha N. Nguyen, Thu-Anh Nguyen, Thuy P. Nguyen, Truong T. Nguyen, Toan T. T. Do, Ngoc T. Pham, and My Hanh Bui. "Estimation of the incubation period of COVID-19 in Vietnam." PLOS ONE 15, no. 12 (December 23, 2020): e0243889. http://dx.doi.org/10.1371/journal.pone.0243889.
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Objective To estimate the incubation period of Vietnamese confirmed COVID-19 cases. Methods Only confirmed COVID-19 cases who are Vietnamese and locally infected with available data on date of symptom onset and clearly defined window of possible SARS-CoV-2 exposure were included. We used three parametric forms with Hamiltonian Monte Carlo method for Bayesian Inference to estimate incubation period for Vietnamese COVID-19 cases. Leave-one-out Information Criterion was used to assess the performance of three models. Results A total of 19 cases identified from 23 Jan 2020 to 13 April 2020 was included in our analysis. Average incubation periods estimated using different distribution model ranged from 6.0 days to 6.4 days with the Weibull distribution demonstrated the best fit to the data. The estimated mean of incubation period using Weibull distribution model was 6.4 days (95% credible interval (CrI): 4.89–8.5), standard deviation (SD) was 3.05 (95%CrI 3.05–5.30), median was 5.6, ranges from 1.35 to 13.04 days (2.5th to 97.5th percentiles). Extreme estimation of incubation periods is within 14 days from possible infection. Conclusion This analysis provides evidence for an average incubation period for COVID-19 of approximately 6.4 days. Our findings support existing guidelines for 14 days of quarantine of persons potentially exposed to SARS-CoV-2. Although for extreme cases, the quarantine period should be extended up to three weeks.
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Navarro Manzano, Esther, Gines Luengo-Gil, Elisa Garcia-Garre, Maria Piedad Fernandez Perez, Ana Fernandez Sanchez, Alejandra Ivars Rubio, Pilar de la Morena, et al. "Circulating miR-200c-3p as a marker of metastatic disease at diagnosis in breast cancer patients." Journal of Clinical Oncology 35, no. 15_suppl (May 20, 2017): e12559-e12559. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e12559.
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e12559 Background: MicroRNAs are involved in cancer biology through their role in regulation of protein expression. The miR-200 family plays a dual role in breast cancer (BC), both regulating epithelial to mesenchymal transition and promoting metastatic colonization. Plasma levels of miR-200 have been previously evaluated as prognostic factors in early and metastatic BC (MBC) but its role as a potential diagnostic marker is less well established. The aim of this study was to determine the potential diagnostic value of miR-200c-3p plasmatic levels in women with locally advanced and metastatic BC. Methods: We included 73 BC patients and 14 controls. Plasma samples were obtained at diagnosis, before treatment. RNA from plasma samples was extracted with NucleoSpin miRNA plasma (Macherey-Nagel). We analyzed expression levels of miR-200c-3p, which were relativized (2-ΔΔCT method) to miR-16. Non-parametric statistical tests were used to determine the association of miR-200c levels with clinical variables. Receiver-operating curves (ROC) were constructed and diagnostic ability evaluated. Kaplan-Meier curves and Cox models were used for survival analyses. Results: 73 BC patients were included: 36 locally advanced BC (LABC) and 37 MBC (7 recurrences and 30 MBC at initial diagnosis [MBCID]). Plasma miR-200c levels were significantly higher in MBC than in controls (p = 0.001) and in LABC (p = 0.001). We found differences neither for age nor for estrogen receptors, HER2, tumor subtype or histology. Overall and disease free survival did not differ by miR-200c levels in any of the groups. Among MBC patients, higher levels were observed in MBCID (p = 0.023). In the group of women with an initial diagnosis of BC (n = 65), high miR-200c levels (over 1st tertile) identified metastatic disease with a sensitivity of 90.0% (95%CI: 72.3-97.4%) and a specificity of 51.4% (95%CI: 34.3-68.3%); negative predictive value: 85.7%; positive predictive value: 61.4%; ROC AUC: 0.79. Conclusions: MiR-200c plasma levels are higher in BC patients with metastatic disease at diagnosis, and might be clinically useful to identify them. Further research on miR200c biological role in MBC and validation in larger populations with sequential samples are warranted.
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Schultz, Nicolai Aagaard, Christian Dehlendorff, Jens Werner, Thor Schutt Svane Nielsen, Dan Calatayud, Nathalia Giese, Benny Vittrup, Kaspar Nielsen, Julia S. Johansen, and Klaus Kaae Andersen. "Diagnostic microRNA serum profile in pancreatic cancer." Journal of Clinical Oncology 30, no. 4_suppl (February 1, 2012): 160. http://dx.doi.org/10.1200/jco.2012.30.4_suppl.160.
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160 Background: MicroRNAs (miRs) regulate genes with important roles in oncogenesis, angiogenesis and tissue differentiation. MiRs have high tissue-specific expression patterns and are interesting new biomarkers with a potential for earlier diagnosis of pancreatic cancer (PC). The aim was: 1) to identify a panel of diagnostic miRs in serum that can separate patients with PC from patients with chronic pancreatitis (CP) and healthy subjects (HS); and 2) to use statistical methods that make the analysis of the miR panel less sensitive to known methodological day-to-day variation. Methods: RNA was purified from serum according to SOP in pretreatment samples stored at −80°C from two prospective studies of 139 patients with PC (101 were operated and 38 had locally or metastatic PC), 17 patients with CP and 50 healthy subjects from 4 University Hospitals. MiR expression was measured using TaqMan Array Human MicroRNA A and B cards (v3.0 Applied Biosystems) profiling 768 miR. Raw miR expression values were checked for outliers. In a univariate selection method the rank of each miR (miRs were ranked for each subject) was related to PC using logistic regression. MiRs with p-values below 0.000001 were tested in a multivariate analysis. Results: Serum samples from 206 patients had acceptable miR. After exclusion of miRs that was undetermined in ≥20% of samples 85 miRs were considered in the univariate analysis and 12 of these subsequently included in the multivariate model. Seven miRs were significantly associated with PC. For all miRs in the diagnostic panel decreased expression is associated with PC. Conclusions: We present a diagnostic panel of 7 miRs in serum that discriminates samples from patients with PC from patients with CP and HS. The 7 miRs were selected with a rank-based method, which is a novel non-parametric method for data processing in miRNA array studies. [Table: see text]
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Ribeiro, Ana Isabel, Ana Cristina Santos, Verónica M. Vieira, and Henrique Barros. "Hotspots of childhood obesity in a large metropolitan area: does neighbourhood social and built environment play a part?" International Journal of Epidemiology 49, no. 3 (October 11, 2019): 934–43. http://dx.doi.org/10.1093/ije/dyz205.
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Abstract Background Effective place-based interventions for childhood obesity call for the recognition of the high-risk neighbourhoods and an understanding of the determinants present locally. However, such an approach is uncommon. In this study, we identified neighbourhoods with elevated prevalence of childhood obesity (‘hotspots’) in the Porto Metropolitan Area and investigated to what extent the socio-economic and built environment characteristics of the neighbourhoods explained such hotspots. Methods We used data on 5203 7-year-old children from a population-based birth cohort, Generation XXI. To identify hotspots, we estimated local obesity odds ratios (OR) and 95% confidence intervals (95%CI) using generalized additive models with a non-parametric smooth for location. Measures of the socio-economic and built environment were determined using a Geographic Information System. Associations between obesity and neighbourhood characteristics were expressed as OR and 95%CI after accounting for individual-level variables. Results At 7 years of age, 803 (15.4%) children were obese. The prevalence of obesity varied across neighbourhoods and two hotspots were identified, partially explained by individual-level variables. Adjustment for neighbourhood characteristics attenuated the ORs and further explained the geographic variation. This model revealed an association between neighbourhood socio-economic deprivation score and obesity (OR = 1.014, 95%CI 1.004–1.025), as well as with the presence of fast-food restaurants at a walkable distance from the residence (OR = 1.37, 1.06–1.77). Conclusions In our geographic area it was possible to identify neighbourhoods with elevated prevalence of childhood obesity and to suggest that targeting such high-priority neighbourhoods and their environmental characteristics may help reduce childhood obesity.
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Moelyo, Annang Giri, Andre Christiawan Susanto, Bella Monika Rajagukguk, and Jonathan Billy Christian Tjiayadi. "Knee height and knee height/height ratio of healthy schoolchildren." Paediatrica Indonesiana 60, no. 5 (July 29, 2020): 233–8. http://dx.doi.org/10.14238/pi60.5.2020.233-8.
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Background Knee height (KH) is rarely used to estimate stature in children, although its measurement might have benefit because not influenced by some musculoskeletal disorder in spinal region. Knee height and knee height/height ratio are typical in children due to different in pubertal timing of each child.
Objective To derive a formula to estimate body height using knee height and to analyze the patterns of knee height and knee height/height ratio of healthy schoolchildren.
Methods This cross-sectional study involved healthy children in one elementary school and one junior high school in Surakarta, Central Java. Demographic data were collected (sex, age, and ethnicity). All anthropometric measurements (height, weight, sitting height, and knee height) were taken three times, and their means were calculated. Linear regression analysis was used to compare height from knee height and sitting height. Non-parametric analysis through locally weighted scatterplot smoothing (LOWESS) was used to analyze the growth patterns of knee height, knee height/height ratio, and sitting height/height ratio.
Results There were 633 children (328 boys and 305 girls) in this study. The formulas for the estimation of height were as follows: for boys, 2.40 × KH (cm) + 1.36 × age (years) + 20.31; and for girls, 2.48 × KH (cm) + 1.15 × age (years) + 19.58 (adjusted R2=0.97). Knee height increased earlier than sitting height in both boys and girls during childhood to adolescent period. Boys had a longer period of knee height increment than girls.
Conclusion Knee height may be a useful alternative to estimate height in children. Knee height increases faster than height and sitting height in both boys and girls.
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Kuželka, K., and R. Marušák. "Use of nonparametric regression methods for developing a local stem form model." Journal of Forest Science 60, No. 11 (November 14, 2014): 464–71. http://dx.doi.org/10.17221/56/2014-jfs.
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A local mean stem curve of spruce was represented using regression splines. Abilities of smoothing spline and P-spline to model the mean stem curve were evaluated using data of 85 carefully measured stems of Norway spruce. For both techniques the optimal amount of smoothing was investigated in dependence on the number of training stems using a cross-validation method. Representatives of main groups of parametric models – single models, segmented models and models with variable coefficient – were compared with spline models using five statistic criteria. Both regression splines performed comparably or better as all representatives of parametric models independently of the numbers of stems used as training data.
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Bourbonne, Vincent, Francois Lucia, Vincent Jaouen, Julien Bert, Olivier Pradier, Dimitris Visvikis, and Ulrike Schick. "VMAT-Based Planning Allows Sparing of a Spatial Dose Pattern Associated with Radiation Pneumonitis in Patients Treated with Radiotherapy for a Locally Advanced Lung Cancer." Cancers 14, no. 15 (July 29, 2022): 3702. http://dx.doi.org/10.3390/cancers14153702.
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Introduction: In patients treated with radiotherapy for locally advanced lung cancer, respect for dose constraints to organs at risk (OAR) insufficiently protects patients from acute pulmonary toxicity (APT), such toxicities being associated with a potential impact on the treatment’s completion and the patient’s quality of life. Dosimetric planning does not take into account regional lung functionality. An APT prediction model combining usual dosimetry features with the mean dose (DMeanPmap) received by a voxel-based volume (Pmap) localized in the posterior right lung has been previously developed. A DMeanPmap of ≥30.3 Gy or a predicted APT probability (ProbAPT) of ≥8% were associated with a higher risk of APT. In the present study, the authors aim to demonstrate the possibility of decreasing the DMeanPmap via a volumetric arctherapy (VMAT)-based adapted planning and evaluate the impact on the risk of APT. Methods: Among the 207 patients included in the initial study, only patients who presented with APT of ≥grade 2 and with a probability of APT ≥ 8% based on the prediction model were included. Dosimetry planning was optimized with a new constraint (DMeanPmap < 30.3 Gy) added to the usual constraints. The initial and optimized treatment plans were compared using the t-test for the independent variables and the non-parametric Mann–Whitney U test otherwise, regarding both doses to the OARs and PTV (Planning Target Volume) coverage. Conformity and heterogeneity indexes were also compared. The risk of APT was recalculated using the new dosimetric features and the APT prediction model. Results: Dosimetric optimization was considered successful for 27 out of the 44 included patients (61.4%), meaning the dosimetric constraint on the Pmap region was achieved without compromising the PTV coverage (p = 0.61). The optimization significantly decreased the median DMeanPmap from 28.8 Gy (CI95% 24.2–33.4) to 22.1 Gy (CI95% 18.3–26.0). When recomputing the risk of APT using the new dosimetric features, the optimization significantly reduced the risk of APT (p < 0.0001) by reclassifying 43.2% (19/44) of the patients. Conclusion: Our approach appears to be both easily implementable on a daily basis and efficient at reducing the risk of APT. Regional radiosensitivity should be considered in usual lung dose constraints, opening the possibility of new treatment strategies, such as dose escalation or innovative treatment associations.
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Mengistu Sissay, Teklay, Melatwork Tibebu, Tagesachew Wasihun, and Aster Tsegaye. "Hematological reference intervals for adult population of Dire Dawa town, East Ethiopia." PLOS ONE 16, no. 2 (February 16, 2021): e0244314. http://dx.doi.org/10.1371/journal.pone.0244314.
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Background Reference interval (RI) for hematological parameters is used to interpret laboratory test results in the diagnosis, management and monitoring of hematologic disorders. Several factors including sex, age, dietary patterns, pregnancy status, ethnicity and geographic location affect hematological RIs. However, manufacturers derived reference value is currently in use in most developing countries including Ethiopia. This study aimed to establish hematological RIs for adult population living in Dire Dawa town, East Ethiopia. Methods In this cross-sectional study, 513 apparently healthy adults of Dire Dawa town were enrolled from January to March 2019. From these, 342 (171 males and 171 non-pregnant females) were aged 18–65 years while 171 were pregnant women aged 15–49 years. After obtaining written informed consent, 5ml fresh whole blood was collected of which 2ml was used for hematologic analysis using Mindray BC-3000plus hematology analyzer and 3ml for serological tests. The 2.5th and 97.5th RI was computed by non-parametric test employing SPSS version 24. P-value <0.05 was considered statistically significant. Result Males had significantly higher reference value for most of red cell parameters (Hgb, RBC, HCT, MCH and MCHC) than females (p <0.05), while most of the WBC parameters were significantly higher in females than males. Moreover, non-pregnant women had higher values for most of red cell parameters than pregnant women. Pregnant women had higher WBC parameters than their non-pregnant counterparts. Conclusion The hematologic RIs obtained in this study shows variation between genders, between pregnant and non-pregnant women, from the clinical practice currently utilised in Dire Dawa town and from studies conducted in Ethiopia, African countries as well as the Western population. It underscores the need for utilising gender and pregnancy specific, locally derived hematologic RI for better management, diagnosis and monitoring of hematologic disorders for adults of both genders and pregnant women.
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Jeong, Suk Hoon, Heon Deok Seo, Boum Young Park, Jae Hong Park, Sung Min Park, Sang Chul Kim, Kee Ho Kim, and Hae Do Jeong. "Electro-Chemical Mechanical Deposition for Planarization of Cu Interconnect." Key Engineering Materials 326-328 (December 2006): 389–92. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.389.
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As copper technology moves from pilot to volume manufacturing, semiconductor fabrication is focused on methods to improve device yield. In especially semiconductor manufacturing, electrochemically deposited copper is the material of choice for advanced interconnect applications. Electrochemical deposition (ECD) employs copper plating electrolytes with organic additives to achieve bottom-up filling of small vias and trench with high aspect-ratios. However, for features with small aspect-ratios, the ECD process yields conformal layers because the additives and the bottom-up fill mechanism are not operative in such large features. So, ECD process does not achieve within-die and within-wafer planarity of the deposited copper layer. For planarization of large features and obtaining globally and locally flat films, an electro-chemical mechanical deposition (ECMD) method has been employed. ECMD process is a novel technique that has ability to deposit planar conductive films on non-planar substrate surfaces. Technique involves simultaneous ECD roles and mechanical sweeping of the substrate surface. Copper layer deposited by the ECMD process grows preferentially in cavities on the wafer surface yielding flat profiles and much reduced overburden thickness. Preferential deposition into the cavities on the substrates surface may be achieved through two different mechanisms. The first mechanism is more mechanical in nature and it involves material removal from the top surface. The second mechanism is more chemical in nature and it involves enhancing deposition into the cavities where mechanical sweeping does not reach, and reducing deposition onto surfaces that are swept. Planar layers obtained by the ECMD technique are suitable for low stress material removal processes. Planar layers also yield improved parametric results in device structures after the material removal step. In this study, we demonstrate mechanical role of pad gives effects in ECMD process. So we evaluate gap-filling and planarization between ECMD and ECD.
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Berz, David, Tina Rizack, Sherry Weitzen, Anthony Mega, Joseph Renzulli, and Gerald Colvin. "Survival of Patients with Squamous Cell Malignancies of the Upper Urinary Tract." Clinical Medicine Insights: Oncology 6 (December 12, 2011): CMO.S8103. http://dx.doi.org/10.4137/cmo.s8103.
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Background Carcinomas of the renal pelvis and ureter are rare diseases, accounting for only about 1% of all urogenital malignancies. Previous reports suggest that squamous cell histology is associated with inferior survival. We present the largest population based analysis to date of survival in patients with upper urinary tract malignancies. Methods We analyzed the Surveillance, Epidemiology and End Results database for cancer specific survival rates in patients with renal pelvis and ureteral malignancies who were diagnosed between 1973 and 2003 in the SEER catchment geographic areas. The primary exposure of interest was the underlying histology, squamous cell versus transitional cell differentiation. We performed descriptive statistics, non parametric survival analysis, and cox proportional hazard analysis. Results We identified 13,213 eligible patients, 7,716 renal pelvis and 5,497 ureteral carcinomas. Among this cohort, 179 patients had squamous cell carcinoma (SCC), 12,395 had transitional cell carcinoma (TCC), including 121 papillary, and 619 had other histologies. Overall, patients with SCC histology fared worse. The median overall survival time was 10 months for SCC and 63 months for TCC. The cox analysis revealed a HR 3.7 (95% CI 3.0–4.5) for SCC when compared to TCC and corrected for decade of diagnosis, age, gender, prior treatment, and race. The difference between the two groups was entirely attributable to survival differences in patients with loco-regional disease. However, when stratified by lymph node involvement this difference disappeared for patients with locally involved lymph nodes ( P = 0.84) and for patients with clear lymph nodes ( P = 0.92). Conclusions SCCs of the upper urinary tract present at a higher clinical stage and appear to represent more aggressive disease when compared to other histologies. However, when appropriately staged according to lymph node status, the survival of TCC and SCC of the upper urinary tract is identical when compared stage by stage.
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Rizack, T., A. Mega, and D. Berz. "Is squamous cell histology an adverse prognosticator for survival of malignancies of the upper urinary tract?" Journal of Clinical Oncology 27, no. 15_suppl (May 20, 2009): 6617. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.6617.
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6617 Background: Carcinomas of the renal pelvis and ureter are rare diseases, accounting for only about 1% of all urogenital malignancies. Previous reports suggest that squamous cell histology is associated with inferior survival. We present the largest population based analysis to date of survival in patients with upper urinary tract malignancies. Methods: We analyzed the Surveillance, Epidemiology and End Results database for cancer specific survival rates in patients with renal pelvis and ureteral malignancies who were diagnosed between 1973 and 2003 in the SEER catchment geographic areas. The primary exposure of interest was the underlying histology, squamous cell versus transitional cell differentiation. We performed descriptive statistics, non parametric survival analysis, and cox proportional hazard analysis. Results: We identified 13,213 eligible patients, 7,716 renal pelvis and 5,497 ureteral carcinomas. Among this cohort, 179 patients had squamous cell carcinoma (SCC), 12,395 had transitional cell carcinoma (TCC), including 121 papillary, and 619 had other histologies. Overall, patients with SCC histology fared worse. The median overall survival time was 10 months for SCC and 63 months for TCC. The cox analysis revealed a HR 0.42 (95% CI 0.36–0.47) for TCC when compared to SCC and corrected for decade of diagnosis, age, gender, prior treatment, and race. The difference between the two groups was entirely attributable to survival differences in patients with loco-regional disease. However, when stratified by lymph node involvement this difference disappeared for patients with locally involved lymph nodes (p = 0.84) and for patients with clear lymph nodes (p = 0.92). Conclusions: SCCs of the upper urinary tract present at a higher clinical stage and appear to represent more aggressive disease when compared to other histologies. However, when appropriately staged according to lymph node status, the survival of TCC and SCC of the upper urinary tract is identical when compared stage by stage. No significant financial relationships to disclose.
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Walshe, J. M., N. Denduluri, A. W. Berman, D. Nguyen, S. Y. Yang, D. J. Liewehr, S. M. Steinberg, F. De Sauvage, H. Chen, and S. M. Swain. "Effect of bevacizumab (BV) and chemotherapy (CT) on serum levels of vascular endothelial growth factor receptor-2 (sVEGFR-2) in patients with inflammatory and locally advanced breast cancer." Journal of Clinical Oncology 24, no. 18_suppl (June 20, 2006): 13003. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.13003.
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13003 Background: VEGFR-2 is a principal mediator of angiogenesis. The effects on sVEGFR-2 after anti-angiogenesis therapy are unknown. Methods: Twenty-one patients (pts) with breast cancer underwent neoadjuvant treatment with BV for 1 cycle (C1) followed by 6 cycles of BV, CT and filgrastim. Blood was collected at baseline (BL), post-cycles 1, 4 and 7. Objectives were to correlate sVEGFR-2 changes after treatment with response, assess wound healing complications, and evaluate for tumor VEGFR-2 mutations. sVEGFR-2 levels were measured by ELISA. Exons 17–26 were sequenced on tissue samples from 20 pts at BL and post C1 to evaluate for VEGFR-2 mutations. Statistical testing is non-parametric. All p-values are two-tailed, with a p < 0.01 interpreted as a statistically significant difference. Results: Thirteen pts had a partial response (PR), 1 unconfirmed PR, 5 stable disease (SD), and 2 progressive disease (PD). Median sVEGFR-2 levels increased by 16% from BL to post C1 (p = 0.0003) and decreased by 19% post C1 to post C4 (p = 0.048). sVEGFR-2 levels were not associated with clinical response. sVEGFR-2 levels at BL did not correlate with other BL parameters: Ki67, microvessel density, VEGF-A, pVEGFR-2, VEGFR-2 or TUNEL (apoptosis). A moderate-weak correlation was seen between post C1 levels of sVEGFR-2 and pVEGFR-2 (r = 0.43). A moderate inverse correlation was seen in the relative difference of sVEGFR-2 and TUNEL from BL to post C1 (r = −0.59). Comparing pts with (n = 5) and without (n = 16) wound healing problems, median sVEGFR-2 levels were 11322 ng/ml and 7524 ng/ml at BL (p = 0.019), 13928 ng/ml and 10148 ng/ml post C1 (p = 0.029), and 10965 ng/ml and 7932 ng/ml post C4 (p = 0.042). In 40 samples where tumor VEGFR-2 sequencing was obtained, no mutations were seen compared to the reference sequence. Conclusion: sVEGFR-2 levels rose significantly following BV alone but were not associated with response. There is a suggestion that sVEGFR-2 may correlate with activated VEGFR2 and a decrease in apoptosis. sVEGFR-2 levels were higher in pts with wound healing problems and may predict pts at higher risk of this complication. There were no mutations of VEGFR2. [Table: see text]
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Ouboter, L., M. Barnhoorn, M. van Pel, J. J. Zwaginga, L. Hawinkels, J. Maljaars, F. Koning, H. Verspaget, and A. van der Meulen - de de Jong. "P363 Locally injected allogeneic bone marrow-derived mesenchymal stromal cells for the treatment of refractory proctitis: clinical results of a phase IIa trial." Journal of Crohn's and Colitis 15, Supplement_1 (May 1, 2021): S381. http://dx.doi.org/10.1093/ecco-jcc/jjab076.487.
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Abstract Background Ulcerative proctitis (UP) can be refractory to treatment, which calls for development of new (local) therapies. Local injection of mesenchymal stromal cells (MSCs) has shown beneficial effects in patients with fistulizing Crohn’s disease and promising results have been obtained when MSCs were locally injected in the bowel of mice with experimental colitis. Our primary aim was to determine the safety, feasibility and tolerability of endoscopically injected allogeneic bone marrow-derived MSCs (bmMSCs) in UP patients. Methods UP patients with endoscopic Mayo score (EMS) 2 or 3, who failed on both rectal 5-ASA and corticosteroids for at least 4 weeks, were eligible for inclusion (EudraCT number 2017-003524-75). Rectal therapies were stopped 2 weeks prior to baseline, but other medication was kept stable until at least 6 weeks after MSC injection. MSCs were locally injected in 4 quadrants of the inflamed rectal submucosa if the inflammation was limited to 7 cm. If the length of inflammation was >7 cm, MSCs were injected in another 4 quadrants more proximally as well. Patients in the first cohort (n=7) were treated with 5*106 MSCs/spot and in the second cohort (n=6) with 10*106MSCs/spot. Adverse events, full Mayo score, fecal calprotectin (FCP), histologic activity (Geboes score [GS]) and quality of life (sIBDQ), were assessed at week 0, 2, 6, 12, and 24, and evaluated by non-parametric paired statistical analyses. Results All reported adverse events were minor, no patients required interventions and no feasibility issues were reported. Median[interquartile range (IQR)] full Mayo score was 11[9.5-12] at baseline, 9[8-11] at week 2 (p=0.003), 8[6-10] at week 6 (p=0.001), and 4[1.5-7] at week 24 (p<0.001). The FCP improved in 9/13 patients at week 2, in 6/13 patients at week 6 and in 11/13 patients at week 24 compared to baseline. The EMS at baseline was 3 (n=10 patients) and 2 (n=3 patients) and improved in some patients at week 2 and 6 (NS). At week 24 the EMS was 3 (n=2), 2 (n=4), 1 (n=5) and 0 (n=2)(p=0.002). The median[IQR] GS decreased after 6 weeks (7(6.5-12.5);p=0.09) and 24 weeks (4[2-8];p=0.01) compared to baseline (10[6.5-12.5]). Median[IQR] sIBDQ showed improvement during follow-up; week 2 (45[37.5-52];p=0.1), week 6 (47[42.50-55];p=0.02), week 12 (59[39.50-62];p=0.001) and week 24 (56[44.50-63.50];p=0.001) compared to baseline (41[34-49,50]). No dose- response effects were observed in our study when comparing cohort 1 and 2. Conclusion Local administration of allogeneic bmMSCs appears safe, tolerable and feasible for the treatment of refractory UP, and shows encouraging indications of clinical efficacy. Further mechanistic and immunological analyses are currently being performed.
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Li, Boren, and Tomonari Furukawa. "Microtexture Road Profiling System Using Photometric Stereo." Tire Science and Technology 43, no. 2 (April 1, 2015): 117–43. http://dx.doi.org/10.2346/tire.15.430204.
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ABSTRACT This paper presents the design and development of a stationary microtexture road profiling system using the photometric stereo (PS) technique. The structure of the developed system is simple, mainly consisting of a digital single-lens reflex (DSLR) camera with a macro lens and multiple light-emitting diodes (LEDs). The camera with the lens is oriented perpendicularly to the pavement texture and takes images each with a different LED turned on at a time. With the pavement texture images with diverse shadings, the PS technique is applied by inverting the image-forming process locally (pixel-wise) to associate the measured image intensities with the known lighting directions to estimate the gradients for each pixel-corresponding surface patch of the pavement texture. Surface normal integration (SNI) is then employed to reconstruct the three-dimensional (3D) road surface in the microtexture scale. The PS-based system has several intrinsic advantages. First, it could achieve high accuracy for surfaces with most diffuse reflection. Second, the measurement speed is fast because of its area-scanning nature. Third, the spatial resolution is high because of the usage of a high-resolution complementary metal-oxide semiconductor DSLR camera. In addition, it can be less sensitive to effects from specularities and shadows compared with most optical-based methods, since images captured under diverse lighting directions in PS provide more cues for detection purposes. Last but not least, the hardware of the system can be made compact at low cost because of its simple structure and can be adapted for direct measurement on the pavement. Parametric studies for the Lambertian-based PS technique were first investigated analytically and numerically, and these investigations yielded the design of the system having eight LEDs with the same zenith angle of 30 degrees and uniformly distributed azimuth angles in 360 degrees. Several experimental results on various types of surfaces have demonstrated that the developed system could achieve the accuracy in the order of 10 microns.
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Castagnoli, Francesca, Simon Doran, Jason Lunn, Anna Minchom, Mary O’Brien, Sanjay Popat, Christina Messiou, and Dow-Mu Koh. "Splenic volume as a predictor of treatment response in patients with non-small cell lung cancer receiving immunotherapy." PLOS ONE 17, no. 7 (July 7, 2022): e0270950. http://dx.doi.org/10.1371/journal.pone.0270950.
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Introduction The spleen is a lymphoid organ and we hypothesize that clinical benefit to immunotherapy may present with an increase in splenic volume during treatment. The purpose of this study was to investigate whether changes in splenic volume could be observed in those showing clinical benefit versus those not showing clinical benefit to pembrolizumab treatment in non-small cell lung cancer (NSCLC) patients. Materials and methods In this study, 70 patients with locally advanced or metastatic NSCLC treated with pembrolizumab; and who underwent baseline CT scan within 2 weeks before treatment and follow-up CT within 3 months after commencing immunotherapy were retrospectively evaluated. The splenic volume on each CT was segmented manually by outlining the splenic contour on every image and the total volume summated. We compared the splenic volume in those achieving a clinical benefit and those not achieving clinical benefit, using non-parametric Wilcoxon signed-rank test. Clinical benefit was defined as stable disease or partial response lasting for greater than 24 weeks. A p-value of <0.05 was considered statistically significant. Results There were 23 responders and 47 non-responders based on iRECIST criteria and 35 patients with clinical benefit and 35 without clinical benefit. There was no significant difference in the median pre-treatment volume (175 vs 187 cm3, p = 0.34), post-treatment volume (168 vs 167 cm3, p = 0.39) or change in splenic volume (-0.002 vs 0.0002 cm3, p = 0.97) between the two groups. No significant differences were also found between the splenic volume of patients with partial response, stable disease or progressive disease (p>0.017). Moreover, there was no statistically significant difference between progression-free survival and time to disease progression when the splenic volume was categorized as smaller or larger than the median pre-treatment or post-treatment volume (p>0.05). Conclusion No significant differences were observed in the splenic volume of those showing clinical benefit versus those without clinical benefit to pembrolizumab treatment in NSCLC patients. CT splenic volume cannot be used as a potentially simple biomarker of response to immunotherapy.