Zeitschriftenartikel: „Postcompression“

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Srinivasan, S., F. Kallel, R. Souchon und J. Ophir. „Analysis of an Adaptive Strain Estimation Technique in Elastography“. Ultrasonic Imaging 24, Nr. 2 (April 2002): 109–18. http://dx.doi.org/10.1177/016173460202400204.

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Elastography is based on the estimation of strain due to tissue compression or expansion. Conventional elastography involves computing strain as the gradient of the displacement (time-delay) estimates between gated pre- and postcompression signals. Uniform temporal stretching of the postcompression signals has been used to reduce the echo-signal decorrelation noise. However, a uniform stretch of the entire postcompression signal is not optimal in the presence of strain contrast in the tissue and could result in loss of contrast in the elastogram. This has prompted the use of local adaptive stretching techniques. Several adaptive strain estimation techniques using wavelets, local stretching and iterative strain estimation have been proposed. Yet, a quantitative analysis of the improvement in quality of the strain estimates over conventional strain estimation techniques has not been reported. We propose a two-stage adaptive strain estimation technique and perform a quantitative comparison with the conventional strain estimation techniques in elastography. In this technique, initial displacement and strain estimates using global stretching are computed, filtered and then used to locally shift and stretch the postcompression signal. This is followed by a correlation of the shifted and stretched postcompression signal with the precompression signal to estimate the local displacements and hence the local strains. As proof of principle, this adaptive stretching technique was tested using simulated and experimental data.

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Yuryk, Yaroslav I. „Morphological features of heart remodeling in the postcompression period of crush syndrome“. BULLETIN OF MEDICAL AND BIOLOGICAL RESEARCH 4, Nr. 1 (04.03.2022): 114–17. http://dx.doi.org/10.11603/bmbr.2706-6290.2022.1.12979.

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Summary. In the postcompression period of crush syndrome regenerative processes develop restorative processes in target organs, in particular in the heart. However, the dynamics of myocardial regenerative changes in the postcompression period in crush syndrome is insufficiently covered in professional literature and requires comprehension study and clarified. The aim of the study – to find out features of regenerative changes in heart of laboratory rats in the dynamics in the postcompression period of crush syndrome. Materials and Methods. Light-optical and polarization were performed examination of the myocardium of 48 laboratory rats after 1, 3, 7 and 14 days (12 animals in each period) after cessation of 6 hour compression of the thigh right pelvic limb. Crush syndrome was modeled under anesthesia by intraperitoneal input of ketamine hydrochloride (100 mg/kg body weight) in a specially designed device, the compression force was 7 kg/cm2, the compressive surface area – 5 cm2. The control group consisted of 12 animals. Results. The stages of myocardial remodeling in the postcompression period are noted, reflecting its structural recovery. In the early postcompression period light-optical disorders predominated microcirculation and alternate changes in acquired cardiomyocytes maximum development after 3 days. After 7 days in myocardial stroma registered cellular infiltrates in which predominate lymphocytes and fybroblasts. Cardiomyocytes lose a compact, gait cells became fortuous, microfoci of contractures were detected and fragmentation, there was a weak proliferation of collagen fibers. After 14 days in the late postcompression period the manifestation do not fade microcirculation disorders. Processes were registered in some areas collagen formation. Conclusions. In the first three days after the cessation of compression of compression of the lower extremity dystrophic–necrotic changes of the myocardium persist in combination with microcirculatory disorders. After 7 days the development of interstitial lympho–histiocytic infiltration is observed against the background of a gradual decrease alternative and hemodynamic processes. After 14 days registration a restoration of myocardial histostructure with residual processes of microfocal contracture of cardiomyocyte degeneration and increased collagen formation are registere

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Planck, S. M., F. W. Klaiber und K. F. Dunker. „Postcompression and Superimposed Trusses for Bridge Rehabilitation“. Journal of Structural Engineering 119, Nr. 3 (März 1993): 978–91. http://dx.doi.org/10.1061/(asce)0733-9445(1993)119:3(978).

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Alonso, Benjamín, Rocío Borrego-Varillas, Íñigo J. Sola, Óscar Varela, Ayalid Villamarín, M. Victoria Collados, Julio San Román, Juan M. Bueno und Luis Roso. „Enhancement of filamentation postcompression by astigmatic focusing“. Optics Letters 36, Nr. 19 (26.09.2011): 3867. http://dx.doi.org/10.1364/ol.36.003867.

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Krynytska, Inna, Ivan Smachylo, Sergii Grabchak und Mariya Marushchak. „Comparative features of bioelements content in blood, liver and bone tissues in a rat model of crush-syndrome“. Bangladesh Journal of Medical Science 23, Nr. 3 (29.07.2024): 714–21. http://dx.doi.org/10.3329/bjms.v23i3.75090.

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Objective: Crush syndrome (CS) remains a life-threatening condition. This research aims to investigate the changes of the macro- and microelement content in blood, liver and bone tissue in a rat model of CS. Methods Studies were conducted on 40 nonlinear mature white male rats. The left hind limb of the rat was subjected to the mechanical pressure for 4 hours. The compressed area was 4 cm with a compressive 2 2 force of 4.25 kg/cm . Determination of total calcium, magnesium and inorganic phosphate contents in blood serum was performed on a semi-automatic biochemical analyser Humalyzer 2000 (Human, Germany) using standard reagent kits. The content of calcium, magnesium, copper and zinc in the liver and bone tissue was determined by atomic absorption spectrometry on a Selmi C-115 M spectrophotometer. Results: It was found that serum content of calcium decreased on the 1st day of observation (by 10.1%), but increased on the 14th day (by 23.0%); the magnesium content progressively decreased during postcompression period, and the content of inorganic phosphate increased on the 14th day of observation by 36.6% (p<0.05) exeeded control data. The content of calcium in the liver tissue started to increase on the 3rd day of observation, and on 14th day by 25.9% (p<0.05) exceeded the control data. Magnesium content in the liver tissue was progressively decreasing during all days of observation. At the same time the content of zinc and copper in the liver tissue gradually increased during postcompression period. The content of calcium, magnesium, zinc and copper in the bone tissue significantly changed from the 3rd day of the postcompression period, in particular the content of bioelements vs. control group progressively decreased by 30.6%, 42.7%, 43.9% and 30.1% respectively on the 14th day of observation. Conclusion : The postcompression period in a rat model of CS is characterized by the pronounced imbalance of macro- and microelements content in blood, liver and bone tissues, which is important for the regulation of metabolic processes. These findings warrant further studies and can be used for developing new treatments that are efficient for dysmacro- and dysmicroelementosis that develop in case of experimental CS. Bangladesh Journal of Medical Science Vol. 23 No. 03 July’24 Page : 714-721

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Thalluri, Chandrashekar, Ruhul Amin, Jithendar Reddy Mandhadi, Amel Gacem, Talha Bin Emran, Biplab Kumar Dey, Arpita Roy et al. „Central Composite Designed Fast Dissolving Tablets for Improved Solubility of the Loaded Drug Ondansetron Hydrochloride“. BioMed Research International 2022 (21.08.2022): 1–13. http://dx.doi.org/10.1155/2022/2467574.

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Ondansetron tablets that are directly compressed using crospovidone and croscarmellose as a synthetic super disintegrant are the subject of this investigation. A central composite, response surface, randomly quadratic, nonblock (version 13.0.9.0) 32 factorial design is used to optimize the formulation (two-factor three-level). To make things even more complicated, nine different formulation batches (designated as F1–F9) were created. There were three levels of crospovidone and croscarmellose (+1, 0, -1). In addition to that, pre- and postcompressional parameters were evaluated, and all evaluated parameters were found to be within acceptable range. Among all postcompressional parameter dispersion and disintegration time, in vitro drug release experiments (to quantify the amount of medication released from the tablet) and their percentage prediction error were shown to have a significant influence on three dependent variables. Various pre- and postcompression characteristics of each active component were tested in vitro. Bulk density, tap density, angle of repose, Carr’s index, and the Hausner ratio were all included in this analysis, as were many others. This tablet’s hardness and friability were also assessed along with its dimension and weight variations. Additional stability studies may be conducted using the best batch of the product. For this study, we utilised the Design-Expert software to select the formulation F6, which had dispersion times of 17.67 ± 0.03 seconds, disintegration times of 120.12 ± 0.55 seconds, and percentage drug release measurements of 99.25 ± 0.36 within 30 minutes. Predicted values and experimental data had a strong correlation. Fast dissolving pills of ondansetron hydrochloride may be created by compressing the tablets directly.

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Balla, Prannay, Ammar Bin Wahid, Ivan Sytcevich, Chen Guo, Anne-Lise Viotti, Laura Silletti, Andrea Cartella et al. „Postcompression of picosecond pulses into the few-cycle regime“. Optics Letters 45, Nr. 9 (24.04.2020): 2572. http://dx.doi.org/10.1364/ol.388665.

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Kaur, Lovleen, Rajni Bala, Neha Kanojia, Manju Nagpal und Gitika Arora Dhingra. „Formulation Development and Optimization of Fast Dissolving Tablets of Aceclofenac Using Natural Superdisintegrant“. ISRN Pharmaceutics 2014 (08.05.2014): 1–10. http://dx.doi.org/10.1155/2014/242504.

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The current research work involves preparation of fast dissolving tablets of Aceclofenac by direct compression method using different concentrations of Lepidium sativum mucilage as natural superdisintegrant. A two-factor three-level (32) factorial design is being used to optimize the formulation. Nine formulation batches (D1–D9) were prepared accordingly. Two factors as independent variables (X1-amount of β-cyclodextrin and X2-amount of Lepidium sativum mucilage) were taken with three levels (+1,0,-1). The levels of two factors were selected on the basis of preliminary experiments conducted and their effect on three dependent variables (disintegration time, wetting time, and in vitro drug release) was studied along with their % prediction error. All the active blends were evaluated for postcompression parameters (angle of repose, Carr’s index, Hausner ratio, etc.) and the tablets were evaluated for postcompression parameters (weight variation, hardness, and friability, wetting time, disintegration time, water absorption ratio, and in vitro drug release studies). The optimum batch was further used for SEM and stability studies. Formulation D5 was selected by the Design-Expert software which exhibited DT (15.5 sec), WT (18.94 sec), and in vitro drug release (100%) within 15 minutes.

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Swart, Gary, Daniel DeBehnke und Jeff Glaspy. „HEMODYNAMIC EFFECTS OF POSTCOMPRESSION CHEST WALL REMODELING IN MECHANICAL CARDIOPULMONARY RESUSCITATION“. Critical Care Medicine 23, Supplement (Januar 1995): A255. http://dx.doi.org/10.1097/00003246-199501001-00451.

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Yaacob, Yusizwan M., Yi Zhang und Damon M. Chandler. „On the Perceptual Factors Underlying the Quality of PostCompression Enhancement of Textures“. Electronic Imaging 2017, Nr. 14 (29.01.2017): 97–103. http://dx.doi.org/10.2352/issn.2470-1173.2017.14.

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Yaacob, Yusizwan M., Yi Zhang und Damon M. Chandler. „On the Perceptual Factors Underlying the Quality of PostCompression Enhancement of Textures“. Electronic Imaging 2017, Nr. 14 (29.01.2017): 97–103. http://dx.doi.org/10.2352/issn.2470-1173.2017.14.hvei-123.

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Hsin, Hsi-Chin, Tze-Yun Sung und Yaw-Shih Shieh. „An Adaptive Coding Pass Scanning Algorithm for Optimal Rate Control in Biomedical Images“. Computational and Mathematical Methods in Medicine 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/935914.

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High-efficiency, high-quality biomedical image compression is desirable especially for the telemedicine applications. This paper presents an adaptive coding pass scanning (ACPS) algorithm for optimal rate control. It can identify the significant portions of an image and discard insignificant ones as early as possible. As a result, waste of computational power and memory space can be avoided. We replace the benchmark algorithm known as postcompression rate distortion (PCRD) by ACPS. Experimental results show that ACPS is preferable to PCRD in terms of the rate distortion curve and computation time.

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Abman, S. H., und F. J. Accurso. „Acute effects of partial compression of ductus arteriosus on fetal pulmonary circulation“. American Journal of Physiology-Heart and Circulatory Physiology 257, Nr. 2 (01.08.1989): H626—H634. http://dx.doi.org/10.1152/ajpheart.1989.257.2.h626.

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To determine the acute effects of increased pulmonary artery pressure and flow on the fetal pulmonary circulation, we studied the response of pulmonary blood flow and vascular reactivity to partial compression of the ductus arteriosus in 22 chronically prepared late-gestation fetal lambs. An inflatable occluder was placed loosely around the ductus arteriosus for compression. Partial compression of the ductus rapidly increased mean pulmonary artery pressure from 45 +/- 1 to 60 +/- 1 mmHg (mean +/- SE) and left pulmonary artery blood flow from 65 +/- 6 to 151 +/- 11 ml/min at 30 min (P less than 0.001; 12 animals). Despite keeping pulmonary artery pressure constant, pulmonary blood flow steadily declined and by 2 h was not different from base-line values. Pulmonary vascular resistance initially fell during the first 30 min of partial compression but then steadily increased and remained elevated above base-line values for at least 30 min after the release of the occluder (P less than 0.001). The decline of pulmonary vascular resistance during the first 30 min of compression was blunted after treatment with the cyclooxygenase inhibitor, meclofenamate (P less than 0.001; 6 animals). Rapid incremental ductus compressions demonstrated a decrease in the slope of the pressure-flow relationship from 3.30 +/- 0.27 (control) to 1.59 +/- 0.21 ml.min-1.mmHg-1 during the postcompression period (P less than 0.001; 12 animals). The vasodilation response to small increases of fetal PO2 was markedly blunted during the postcompression period (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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Johnson, Blair D., Kieren J. Mather, Sean C. Newcomer, Timothy D. Mickleborough und Janet P. Wallace. „Vitamin C prevents the acute decline of flow-mediated dilation after altered shear rate patterns“. Applied Physiology, Nutrition, and Metabolism 38, Nr. 3 (März 2013): 268–74. http://dx.doi.org/10.1139/apnm-2012-0169.

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Oscillatory and retrograde shear rate (SR) impairs endothelial function, potentially through shear-induced oxidative stress. We tested the hypothesis that acute vitamin C supplementation would prevent the attenuation of brachial artery flow-mediated dilation (FMD) after a period of augmented oscillatory and retrograde SR. Twelve healthy men (aged 26 ± 3 years) participated in two 30-min study visits in which one arm was subjected to increased oscillatory and retrograde SR, using 60 mm Hg of forearm cuff compression, and the contralateral arm served as the control. Subjects ingested capsules containing either placebo (sucrose) or vitamin C at 90 and 120 min (1000 mg total vitamin C) prior to cuff compression periods in a randomized placebo-controlled double-blind crossover study. Oscillatory and retrograde SR in the cuffed arms increased during the compression periods in the placebo and vitamin C study visits (p < 0.01 for both), with no difference between studies (p > 0.05). Antegrade SR remained unchanged throughout the compression periods (p > 0.05), and mean SR was lower in the cuffed arm than in the control arm for both study visits (p < 0.05). FMD decreased after cuff compression in the placebo cuffed arm (precompression vs. postcompression, 5.2% ± 1.4% vs. 3.5% ± 1.4%; p < 0.05), but remained unchanged after vitamin C therapy in the cuffed arm (precompression vs. postcompression, 5.3% ± 2.4% vs. 5.7% ± 2.6%; p > 0.05). No FMD changes were observed in the control arm for either study visit (p > 0.05). These data demonstrate that acute vitamin C supplementation prevents the attenuation of FMD due to altered SR patterns, suggesting that oxidative stress contributes to the oscillatory and retrograde SR-induced impairment of FMD.

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Korni, Rama D., Kamala KPV und V. Sahiti. „Fast Dissolving Tablets of Promethazine Theoclate: Optimization by Box Behnken Design“. INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 14, Nr. 01 (25.03.2024): 126–31. http://dx.doi.org/10.25258/ijddt.14.1.18.

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HThe current work was planned to optimize promethazine theoclate fast-dissolving tablets using Box Behnken design. The effect of three independent factors, the concentration of camphor (sublimating agent), sodium starch glycolate (superdisintegrant) and β-cyclodextrin (solubility enhancer) on two responses, disintegration time and percent drug release was studied. A total of 27 formulations were prepared and tested for various precompression and postcompression parameters. The correlation between factors and responses was established by plotting contour plots. The independent variables, the concentration of camphor and sodium starch glycolate, have a significant influence on response disintegration time, whereas the factor, concentration of β-cyclodextrin, has an effect on the response and percent drug release.

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Jiang, Zhaoneng, Ru-shan Chen, Zhenhong Fan und Maomao Zhu. „Novel postcompression technique in the matrix decomposition algorithm for the analysis of electromagnetic problems“. Radio Science 47, Nr. 2 (22.03.2012): n/a. http://dx.doi.org/10.1029/2011rs004921.

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Yuryk, Ya I., und I. I. Yuryk. „MORPHOLOGICAL FEATURES OF ADRENAL GLAND REMODELING IN THE EARLY POSTCOMPRESSION PERIOD OF CRUSH SYNDROME“. Bulletin of Problems Biology and Medicine 1, Nr. 3 (2024): 325. http://dx.doi.org/10.29254/2077-4214-2024-3-174-325-332.

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M, Jyoshna, Santhi Elveena Alagala, Charishma Manyam, Raju Thoti, Jyothika Pulicherla, Madhavi Udayagiri und Swathi Krishna KV. „Formulation and Evaluation of Commiphora wightii Herbal Pills Treatment of Anti-Obesity“. International Journal of Clinical Pharmacokinetics and Medical Sciences 4, Nr. 2 (23.05.2024): 21–28. http://dx.doi.org/10.26452/ijcpms.v4i2.614.

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An excessive quantity of bodily fat characterizes a complex disorder called obesity. It raises the risk of developing other illnesses and medical conditions like diabetes, high blood pressure, and heart conditions. When our BMI is 30kg/m2 or greater, obesity is considered to exist. Today, more ailments are treated with traditional herbal medicines than allopathic ones. Compared to herbal medications, allopathic drugs have higher side effects. The current work aims to create and assess the herbal tablet prepared using an ethanolic extract of Commiphora wightii leaves. Wet granulation was used to manufacture the formulation. Both the pre-compression parameter and the post-compression parameter of the prepared formulation were assessed. The calculation demonstrated that the permissible pre and postcompression parameters are within bounds.Top of Form

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Hort, Ondřej, Antoine Dubrouil, Amélie Cabasse, Stéphane Petit, Eric Mével, Dominique Descamps und Eric Constant. „Postcompression of high-energy terawatt-level femtosecond pulses and application to high-order harmonic generation“. Journal of the Optical Society of America B 32, Nr. 6 (08.05.2015): 1055. http://dx.doi.org/10.1364/josab.32.001055.

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Yuryk, Ya I. „PECULIARITIES OF ANTIOXIDANT PROTECTION IN HEART AND BLOOD TISSUE RATS IN THE POSTCOMPRESSION PERIOD OF CRUSH SYNDROME“. Bulletin of Problems Biology and Medicine 4, Nr. 1 (2021): 214. http://dx.doi.org/10.29254/2077-4214-2021-4-162-214-217.

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Bergenheim, A. Tommy, und Bengt Linderoth. „DIPLOPIA AFTER BALLOON COMPRESSION OF RETROGASSERIAN GANGLION ROOTLETS FOR TRIGEMINAL NEURALGIA“. Neurosurgery 62, Nr. 2 (01.02.2008): E533—E534. http://dx.doi.org/10.1227/01.neu.0000316025.58915.10.

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Abstract OBJECTIVE Balloon compression of the rootlets behind the trigeminal ganglion for the treatment of trigeminal neuralgia has become an increasingly popular method among neurosurgeons. However, the method has recognized complications, including double vision. Although occurring infrequently, diplopia may cause the patient significant disability. To minimize the risk for this complication, we analyzed our patients with respect to the surgical technique. METHODS We reviewed our joint consecutive series of 193 patients with trigeminal neuralgia treated with balloon compression. The medical records and the intraoperative x-ray images were analyzed. RESULTS We identified six patients with double vision postoperatively. In analyzing these occurrences, we found that the balloon was inflated outside Meckel's cave in four patients, the balloon was initially inflated too deeply in one patient, and the anatomy of Meckel's cave was probably aberrant in one patient. In five of the six patients, the symptoms resolved within 5 months. CONCLUSION By meticulous surgical technique with close attention to the anatomic position and the shape of the inflated balloon, most cases of postcompression diplopia should be avoided.

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Desai, Raghavendra Reddy, Thomas A. Krouskop und Raffaella Righetti. „Elastography Using Harmonic Ultrasonic Imaging: A Feasibility Study“. Ultrasonic Imaging 32, Nr. 2 (April 2010): 103–17. http://dx.doi.org/10.1177/016173461003200204.

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Tissue Harmonic Imaging (THI) is a relatively new modality that has had a significant impact in the ultrasound field. In the recent past, imaging the mechanical properties of tissues using elastography has also gained great interest. In this paper, we investigate the feasibility of combining these two state-of-the-art ultrasound-imaging modalities. The performance of elastograms obtained using harmonic ultrasonic signals is studied with simulations and compared to the performance of conventional elastograms using standard statistical methods. Experiments are used as a proof of the technical feasibility of generating tissue-harmonic elastograms using experimental harmonic signals. The results of our simulation study indicate that all image quality factors considered in this study (elastographic signal-to-noise ratio, elastographic contrast-to-noise ratio and spatial resolution) may be improved when using harmonic ultrasonic signals, provided that the ultrasound system is characterized by high bandwidth, high sampling frequency and large lateral sampling. Preliminary experimental results suggest that it is technically feasible to generate experimental elastograms using harmonic signals, provided that the sonographic signal-to-noise ratio of the pre- and postcompression harmonic frames is sufficiently high to guarantee reliable values of correlation.

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Céspedes, Ignacio, und Jonathan Ophir. „Reduction of Image Noise in Elastography“. Ultrasonic Imaging 15, Nr. 2 (April 1993): 89–102. http://dx.doi.org/10.1177/016173469301500202.

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Elastography is a method for imaging the elastic properties of compliant tissues which produces gray scale elasticity images called elastograms. The elastograms of phantoms with homogeneous elastic properties exhibit a noisy appearance. We demonstrate that this noisy appearance of the elastograms is due to the nonstationary relationship between the pre- and postcompression signals that results in an artifactual modulation of the strain estimates by the amplitude variations of the envelope of the rf signal. We have identified two methods to reduce the strain modulation artifact. The first method consists of reducing the signal amplitude swings within the observation windows by logarithmically or otherwise compressing the rf signal. The sensitivity of this method to amplitude compression strength and the ability to reduce the noise in the elastograms without affecting the spatial resolution are investigated through simulations. The second method to reduce the strain modulation artifact consists of temporal stretching of the signal obtained after physical compression to approximate the shape of the signal obtained before compression. In this paper, we discuss the first method. The results show that significant improvement in image noise can be obtained with logarithmic amplitude compression. This improvement is obtained in conjunction with improved spatial resolution.

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Chen, Xiao, und Xiaoqing Xu. „A Fast and Efficient Adaptive Threshold Rate Control Scheme for Remote Sensing Images“. Scientific World Journal 2012 (2012): 1–6. http://dx.doi.org/10.1100/2012/691413.

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The JPEG2000 image compression standard is ideal for processing remote sensing images. However, its algorithm is complex and it requires large amounts of memory, making it difficult to adapt to the limited transmission and storage resources necessary for remote sensing images. In the present study, an improved rate control algorithm for remote sensing images is proposed. The required coded blocks are sorted downward according to their numbers of bit planes prior to entropy coding. An adaptive threshold computed from the combination of the minimum number of bit planes, along with the minimum rate-distortion slope and the compression ratio, is used to truncate passes of each code block during Tier-1 encoding. This routine avoids the encoding of all code passes and improves the coding efficiency. The simulation results show that the computational cost and working buffer memory size of the proposed algorithm reach only 18.13 and 7.81%, respectively, of the same parameters in the postcompression rate distortion algorithm, while the peak signal-to-noise ratio across the images remains almost the same. The proposed algorithm not only greatly reduces the code complexity and buffer requirements but also maintains the image quality.

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Auguste, Thierry, Oliver Gobert, Coralie Fourcade Dutin, Antoine Dubrouil, Eric Mével, Stéphane Petit, Eric Constant und Dominique Descamps. „Application of optical-field-ionization-induced spectral broadening in helium gas to the postcompression of high-energy femtosecond laser pulses“. Journal of the Optical Society of America B 29, Nr. 6 (17.05.2012): 1277. http://dx.doi.org/10.1364/josab.29.001277.

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Seidel, Marcus, Prannay Balla, Chen Li, Gunnar Arisholm, Lutz Winkelmann, Ingmar Hartl und Christoph M. Heyl. „Factor 30 Pulse Compression by Hybrid Multipass Multiplate Spectral Broadening“. Ultrafast Science 2022 (01.04.2022): 1–10. http://dx.doi.org/10.34133/2022/9754919.

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As ultrafast laser technology advances towards ever higher peak and average powers, generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge. Here, we present a very compact and highly robust method to compress 1.24 ps pulses to 39 fs by means of only a single spectral broadening stage which neither requires vacuum parts nor custom-made optics. Our approach is based on the hybridization of the multiplate continuum and the multipass cell spectral broadening techniques. Their combination leads to significantly higher spectral broadening factors in bulk material than what has been reported from either method alone. Moreover, our approach efficiently suppresses adverse features of single-pass bulk spectral broadening. We use a burst-mode Yb:YAG laser emitting pulses with 80 MW peak power that are enhanced to more than 1 GW after postcompression. With only 0.19% rms pulse-to-pulse energy fluctuations, the technique exhibits excellent stability. Furthermore, we have measured state-of-the-art spectral-spatial homogeneity and good beam quality of M2=1.2 up to a spectral broadening factor of 30. Due to the method’s simplicity, compactness, and scalability, it is highly attractive for turning a picosecond laser into an ultrafast light source that generates pulses of only a few tens of femtoseconds duration.

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Sravya, Maddukuri, Rajamanickam Deveswaran, Srinivasan Bharath, Basappa Veerbadraiah Basavaraj und Varadharajan Madhavan. „Development of Orodispersible Tablets of Candesartan Cilexetil-β-cyclodextrin Complex“. Journal of Pharmaceutics 2013 (24.09.2013): 1–13. http://dx.doi.org/10.1155/2013/583536.

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The aim of this study was to investigate the use of inclusion complexation technique employing β-cyclodextrin in improving the dissolution profile of candesartan cilexetil, a BCS class-II drug, and to formulate the inclusion complex into orodispersible tablets. The inclusion complexes were formed by physical mixing, kneading, coevaporation, and lyophilisation methods. Inclusion complexes were characterized by FTIR, DSC, XRD, NMR, and mass spectral studies. Inclusion complexes prepared using kneading, and lyophilisation techniques in the molar ratio 1 : 5 with β-cyclodextrin were used for formulating orodispersible tablets by direct compression with different superdisintegrants like croscarmellose sodium, crospovidone, sodium starch glycolate, and low substituted hydroxypropyl cellulose in varying concentrations. The directly compressible powder was evaluated for precompression parameters, and the prepared orodispersible tablets were evaluated for postcompression parameters. Drug-excipient compatibility studies showed no interaction, and characterization proved the formation of inclusion complex. In vitro disintegration time was found to be within 3 minutes, and all the formulations showed complete drug release of 100% within 20 minutes. The optimized formulation was found to be stable after 6 months and showed no significant change in drug content. This work proved β-cyclodextrins to be effective solubilizing agent in improving the solubility of poorly water soluble drugs.

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Srinivasan, S., J. Ophir und S. K. Alam. „Elastographic Imaging Using Staggered Strain Estimates“. Ultrasonic Imaging 24, Nr. 4 (Oktober 2002): 229–45. http://dx.doi.org/10.1177/016173460202400403.

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Conventional techniques in elastography estimate strain as the gradient of the displacement estimates obtained through crosscorrelation of pre- and postcompression rf A-lines. In these techniques, the displacements are estimated over overlapping windows and the strains are estimated as the gradient of the displacement estimates over adjacent windows. The large amount of noise at high window overlaps may result in poor quality elastograms, thus restricting the applicability of conventional strain estimation techniques to low window overlaps, which, in turn, results in a small number of pixels in the image. To overcome this restriction, we propose a multistep strain estimation technique. It computes the first elastogram using nonoverlapped windows. In the next step, the data windows are shifted by a small distance (small fraction of window size) and another elastogram is produced. This is repeated until the cumulative shift equals/exceeds the window size and all the elastograms are staggered to produce the final elastogram. Simulations and experiments were performed using this technique to demonstrate significant improvement in the elastographic signal-to-noise ratio ( SNRe) and the contrast-to-noise ratio ( CNRe) at high window overlaps over conventional strain estimation techniques, without noticeable loss of spatial resolution. This technique might be suitable for reducing the algorithmic noise in the elastograms at high window overlaps.

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Swamy, N. G. N., P. Shilpa und Z. Abbas. „FORMULATION AND CHARACTERIZATION OF MEDICATED CHEWING GUMS OF DEXTROMETHORPHAN HYDROBROMIDE“. INDIAN DRUGS 49, Nr. 12 (28.12.2012): 29–35. http://dx.doi.org/10.53879/id.49.12.p0029.

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Chewing gums are mobile drug delivery systems, with a potential for administering drugs either for local action or for systemic absorption via buccal route. Dextromethorphan hydrobromide chewing gum formulations were made employing Pharmagum M as the base with an aim to overcome the firstpass effect, reducing the risk of overdosing, ease of administration and for achieving faster systemic absorption. Dextromethorphan hydrobromide was further transformed into spray dried form and incorporated into Pharmagum M base with the object of solubility enhancement and masking the bitter taste of the drug. The prepared medicated chewing gums were evaluated for various precompression and postcompression parameters. The in vitro drug release profiles were carried out employing Erweka DRT chewing apparatus. It was observed that increasing the chewing gum base concentration resulted in a decreased drug release profile. The drug in the spray dried form revealed improved performance in comparison to the directly contained drug. The drug release data were fitted into various kinetic models. It was observed that the drug release was matrix diffusion controlled and revealed a non-Fickian drug release mechanism. Accelerated stability studies were carried out on select formulations as per ICH guidelines. The formulations were found to be stable in respect to physical parameters and no significant deviations were seen in respect to in vitro drug release characteristics.

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Yasmin Begum, M., Ali Alqahtani, Mohammed Ghazwani, Noura Abdullah Alhamood, Umme Hani, Avanthi Jajala und Mohamed Rahamathulla. „Development of Duloxetine Hydrochloride Tablets for Delayed and Complete Release Using Eudragit L 100“. International Journal of Polymer Science 2021 (26.03.2021): 1–10. http://dx.doi.org/10.1155/2021/8890503.

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The purpose of the research was to optimize the preparation of duloxetine hydrochloride (duloxetine HCl) delayed release tablets. Duloxetine HCl produces a toxic substance called alpha-naphthol when duloxetine HCl is in contact with gastric fluid. Thus, duloxetine HCl when given orally needed a protective enteric coating that disable the delivery of duloxetine HCl in gastric fluid while enabling the drug delivery only in small intestine. Four different core tablets were prepared by direct compression technique, and the one which displayed quick disintegration and dissolution was chosen for enteric coating. The compressed tablets were enteric coated by dip coating technique. Since subcoating is required to safeguard the enteric coating, the core tablets were subcoated by using polymer HPMC K15M and then enteric coated with Eudragit L 100. The prepared tablets were assessed for the entire precompression and postcompression characteristics. FTIR study revealed the existence of all prominent peaks signifying its compatibility and authenticity. The in vitro studies showed that enteric-coated tablets were capable of restricting release in acidic media. The formulation F8 was optimised with 5% and 15% increase in weight of seal coat and enteric coat with good dissolution profile. Stability studies revealed that the optimized formulation was intact without any deterioration for 3 months. In conclusion, the optimized formulation could resist the drug release in acidic environment of gastrointestinal region and release the drug at a time once the tablet reaches the intestine.

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Righetti, Raffaella, Jonathan Ophir, Brian S. Garra, Rajah M. Chandrasekhar und Thomas A. Krouskop. „A New Method for Generating Poroelastograms in Noisy Environments“. Ultrasonic Imaging 27, Nr. 4 (Oktober 2005): 201–20. http://dx.doi.org/10.1177/016173460502700401.

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Poroelastography has been recently introduced as a new elastographic technique that may be used to describe the spatial and temporal behavior of poroelastic materials. The experimental methodology proposed thus far for phantoms and tissues in vitro requires the acquisition of a precompression rf frame, the application of a unit step strain compression to the sample and the acquisition of subsequent post-compression frames from the material. Elastograms and poroelastograms are generated by cross-correlating the sequentially-acquired postcompression frames with the reference precompression frame. The application of poroelastography to tissues in vivo must address the echo decorrelation problems that are encountered due to uncontrolled tissue motion, which may become significant shortly after the acquisition of the precompression frame. In this paper, we investigate the feasibility of performing poroelastography experiments using an alternative experimental scheme. In the proposed experimental methodology, the reference precompression frame is continuously moved while the time interval between the frames that are correlated is kept short. This allows long data acquisition times with simultaneous minimization of the decorrelation due to undesired tissue motion in vivo. We validated this new method using both a step and a ramp compression functions. We performed poroelastographic simulations and experiments in phantoms and in tissues in vivo. The results were compared to those obtained using the traditional acquisition methodology. This study shows that the two methods yield similar results in vitro and suggests that the new method may be more robust to decorrelation noise in applications in vivo.

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Dhakal, Bhawana, Jaybir Kumar Thakur, Reema Kumari Mahato, Ishwori Rawat, D. C. Rabin, Rahul Rana Chhetri, Kedar Prasad Shah, Atul Adhikari und Jitendra Pandey. „Formulation of Ebastine Fast-Disintegrating Tablet Using Coprocessed Superdisintegrants and Evaluation of Quality Control Parameters“. Scientific World Journal 2022 (19.05.2022): 1–13. http://dx.doi.org/10.1155/2022/9618344.

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Ebastine is a long-acting, nonsedating, second-generation antihistaminic drug that prevents histamine action, mainly in immediate hypersensitivity. This project was aimed to formulate and characterize orodispersible tablets of ebastine, utilizing different proportions of three disintegrants, namely crospovidone, sodium starch glycolate, and coprocessed superdisintegrant. Initially, fifteen trial batches of ebastine orodispersible tablets were outlined using the central composite design of Minitab software. The tablets were formulated by the direct compression method. The compressed tablets were then evaluated for precompression and postcompression physicochemical parameters, such as angle of repose, Carr’s index, Hausner’s ratio, hardness, thickness, weight variation, drug content, friability, wetting time, disintegration time, dispersion time, and water absorption ratio. The in vitro dissolution test was conducted according to Indian Pharmacopeia 2018, with the help of the rotating paddle method using 0.5% w/v sodium lauryl sulfate buffer in 0.1 N HCl. For the optimized batch (8th batch), all the physicochemical parameters like angle of repose (33.77°), Carr’s index (19.34%), Hausner’s ratio (1.24), weight variation (202.5 mg), hardness (4.3 kg/cm2), friability (0.44%), thickness (3.16 mm), dissolution (95.78%), and drug content (101.67%) were within the acceptable limit as per Indian Pharmacopeia 2018. The wetting time, disintegration time, dispersion time, and water absorption ratio were reported to be 25.1 seconds, 16.0 seconds, 38.6 seconds, and 91.92%, respectively. Hence, the results suggested that orodispersible tablets of ebastine can be formulated. Furthermore, the mixing of crospovidone, sodium starch glycolate, and coprocessed super disintegrants can result in excellent desirable properties in the orodispersible tablet.

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Bayomy, ElSayed Mahmoud, Ahmed Taha Atallah, Mohamed Ebrahim Al-Ashhab und Shareef Abd Elmoneim Aeltraigy. „Evaluation of the Results of Reconstruction of Medial Patellofemoral Ligament in the Treatment of Recurrent Patellar Instability Using Hamstring Autograft by Dual Patella Docking Technique“. Journal of Arthroscopy and Joint Surgery 11, Nr. 2 (2024): 69–75. http://dx.doi.org/10.4103/jajs.jajs_62_23.

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Abstract Background: Recurrent patellar instability can significantly affect a patient’s life quality. This study evaluated the results of medial patellofemoral ligament (MPFL) reconstruction in the recurrent patellar instability treatment using hamstring autograft by dual patellar docking technique. Materials and Methods: This prospective study was performed on 20 recurrent patellar instability patients. Magnetic resonance imaging and computed tomography scans were performed to confirm MPFL tear and assess the tibial tubercle-trochlear groove distance. Various clinical and radiographic evaluations were performed preoperatively. The surgical technique involved diagnostic arthroscopy, graft preparation, patellar preparation, graft passage, femoral tunnel preparation, and graft fixation. Results: Postoperatively, a substantial progression was observed in the International Knee Documentation Committee score, Kujala score, Cincinnati score, and Lysholm score compared to preoperative values (P < 0.001). In addition, the postoperative measurements of patellar tilt angle and patellar congruence angle were significantly lower than their respective preoperative values (P < 0.001). All 20 (100%) patients had negative findings in the postapprehension test, indicating improved stability. In the postcompression test, 3 (15%) patients showed positive results, whereas 17 (85%) patients had negative results. In terms of complications, 2 (10%) patients experienced patellofemoral pain, 1 (5%) patient had residual patellar translation without dislocation, 1 (5%) patient had limited flexion, and the majority of patients (16, 80%) had no complications. Conclusions: MPFL reconstruction with patellar docking yielded good results with Kujala and Lysholm, as well as adequate, satisfactory congruence angles for most patients. This procedure has exhibited a high success rate in addressing patellofemoral instability.

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Uddin, Ajam, Shimul Halder, Nandita Deb, Harinarayan Das, Madhabi Lata Shuma, Ikramul Hasan, Manik Chandra Shill und Syed Shabbir Haider. „Impact of Methods of Preparation on Mechanical Properties, Dissolution Behavior, and Tableting Characteristics of Ibuprofen-Loaded Amorphous Solid Dispersions“. Advances in Pharmacological and Pharmaceutical Sciences 2024 (28.05.2024): 1–15. http://dx.doi.org/10.1155/2024/2303942.

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This study aims to improve the biopharmaceutical, mechanical, and tableting properties of a poorly soluble drug, ibuprofen (IBP), by preparing amorphous solid dispersion (ASD) followed by a sustained-release tablet formulation. A suitable polymer to develop an ASD system was chosen by utilizing the apparent solubility of IBP in various polymer solutions. ASDs containing various ratios of IBP and selected polymer were prepared by the melt fusion (MF) method. ASD containing optimized drug-polymer ratio prepared by freeze-drying (FD) method was characterized and compared physicochemically. The solubility of IBP in water increased 28-fold and 35-fold when formulated as ASD by MF and FD, respectively. Precise formulations showed amorphization of IBP and increased surface area, improving solubility. The dissolution pattern of optimized ASD-IBP in pH 6.8 phosphate buffer after 60 min in MF and FD was enhanced 3-fold. In addition, direct compression tablets comprising optimized ASD granules from MF and FD were made and assessed using compendial and noncompendial methods. ASD-IBP/MF and ASD-IBP/FD formulations showed a similar drug release profile. In addition, 12 h of sustained IBP release from the ASD-IBP-containing tablets was obtained in a phosphate buffer with a pH of 6.8. From the dissolution kinetics analysis, the Weibull model fitted well. The drug release pattern indicated minimal variations between tablets formed using ASD-IBP prepared by both procedures; however, pre- and postcompression assessment parameters differed. From these findings, the application of ASD and sustained-release polymers in matrix formation might be beneficial in improving the solubility and absorption of poorly soluble drugs such as IBP.

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Smielewski, Piotr, Marek Czosnyka, Peter Kirkpatrick und John D. Pickard. „Evaluation of the transient hyperemic response test in head-injured patients“. Journal of Neurosurgery 86, Nr. 5 (Mai 1997): 773–78. http://dx.doi.org/10.3171/jns.1997.86.5.0773.

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✓ The transient hyperemic response test has been shown to provide an index of cerebral autoregulation in healthy individuals and in patients who have suffered a subarachnoid hemorrhage. In this study, the test was applied to patients who had received a severe head injury, and the value of the test was assessed by comparing its result with the individual's clinical condition (Glasgow Coma Scale [GCS] score), cerebral perfusion pressure (CPP), transcranial Doppler wave form—derived index for cerebral autoregulation (relationship between the CPP and the middle cerebral artery flow velocity), and outcome (Glasgow Outcome Scale [GOS] score). Forty-seven patients, aged 16 to 63 years, with head injuries were included in the study. Signals of intracranial pressure, arterial blood pressure, flow velocity, and cortical microcirculatory flux were digitized and recorded for a period of 30 minutes using special computer software. Two carotid compressions were performed at the beginning of each recording. The transient hyperemic response ratio (THRR: the ratio of the hyperemic flow velocity recorded after carotid release and the precompression baseline flow velocity) was calculated, as was the correlation coefficient Sx used to describe the relationship between slow fluctuations in the systolic flow velocity and CPP throughout the period of recording. No significant changes in CPP were found during compression. There was a significant correlation between the THRR and the Sx (r = 0.49, p < 0.0001). The hyperemic response proved to be lower in patients who exhibited a poor clinical grade at presentation (GCS scores < 6, p = 0.01) and lower in patients achieving a poor outcome (GOS scores of 3, 4, and 5, p = 0.003). Loss of postcompression hyperemia occurred when the CPP fell below 50 mm Hg. The carotid compression test provides a simple index of cerebral autoregulation that is relevant to the clinical condition and outcome of the severely head injured patient.

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Chowdary, Y. Ankamma, Ramakrishna Raparla und Muramshetty Madhuri. „Formulation and Evaluation of Multilayered Tablets of Pioglitazone Hydrochloride and Metformin Hydrochloride“. Journal of Pharmaceutics 2014 (12.05.2014): 1–14. http://dx.doi.org/10.1155/2014/848243.

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In the treatment of type 2 diabetes mellitus a continuous therapy is required which is a more complex one. As in these patients there may be a defect in both insulin secretion and insulin action exists. Hence, the treatment depends on the pathophysiology and the disease state. In the present study, multilayered tablets of pioglitazone hydrochloride 15 mg and metformin hydrochloride 500 mg were prepared in an attempt for combination therapy for the treatment of type 2 diabetes mellitus. Pioglitazone HCl was formulated as immediate release layer to show immediate action by direct compression method using combination of superdisintegrants, namely, crospovidone and avicel PH 102. Crospovidone at 20% concentration showed good drug release profile at 2 hrs. Metformin HCl was formulated as controlled release layer to prolong the drug action by incorporating hydrophilic polymers such as HPMC K4M by direct compression method and guar gum by wet granulation method in order to sustain the drug release from the tablets and maintain its integrity so as to provide a suitable formulation. The multilayered tablets were prepared after carrying out the optimization of immediate release layer and were evaluated for various precompression and postcompression parameters. Formulation F13 showed 99.97% of pioglitazone release at 2 hrs in 0.1 N HCl and metformin showed 98.81% drug release at 10 hrs of dissolution in 6.8 pH phosphate buffer. The developed formulation is equivalent to innovator product in view of in vitro drug release profile. The results of all these evaluation tests are within the standards. The procedure followed for the formulation of these tablets was found to be reproducible and all the formulations were stable after accelerated stability studies. Hence, multilayered tablets of pioglitazone HCl and metformin HCl can be a better alternative way to conventional dosage forms.

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Aleti, Rajeswari, Monika Nijhawan, Sailaja Gunnam, Mohammad Bakhatwar, Pavan Kumar Thota, Krishna Kishore Adireddy und Srinivasa Rao Baratam. „Investigation of Groundnut Shell Powder as Potential Super Disintegrant in Chronotherapeutic Delivery of Sacubitril–valsartan“. Asian Journal of Pharmaceutical Research and Health Care 16, Nr. 3 (Juli 2024): 316–21. http://dx.doi.org/10.4103/ajprhc.ajprhc_71_24.

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ABSTRACT Context: Chronotherapeutic delivery of antihypertensives plays a potential role in the treatment by providing a therapeutic amount of drug at the target site in the body. Sacubitril–valsartan (SV), an angiotensin receptor neprilysin inhibitor, has been indicated for the treatment of hypertension. The study explores the formulation and evaluation of compression-coated tablets (CCTs) of SV using a natural super disintegrant in the core tablet for chronotherapeutic drug delivery. Aim and Objective: The main objective of the current investigation is to study the applicability of groundnut shell powder (GSP) as super disintegrant and its role in chronotherapeutic drug delivery. Materials and Methods: Core tablets of SV were prepared using different concentrations of natural excipient (GSP) and compression coated. The CCT was evaluated for the postcompression tableting properties, in vitro drug release, Fourier transform infra red spectroscopy (FTIR), and stability studies and compared the disintegrating property with a synthetic excipient (crospovidone). Results: The results of the in vitro dissolution performance of core tablets indicated that the incorporation of GSP as a super disintegrant significantly reduced the disintegration time. Optimized core tablets were subjected to compression coating using a graded concentration of cellulose acetate phthalate as coating polymer and evaluated tableting properties and dissolution performance. Among all the formulations, CCT5 with 8% GSP in the core, coated with 300 mg coating polymer shown 6 h lag time followed by the rapid release of the drug within 1 h. Accelerated stability studies on optimized formulation revealed that there were no significant changes in the tableting parameters after storage indicating the stability of the formulation. Conclusion: The use of natural disintegrant in the core tablet offers a promising approach for rapid release of drug from CCT after a lag time of 6 h to achieve chronotherapy of SV.

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Thulluru, Ashok, Veeravalli Kumar Sai, Pavan Kumar M und Roshitha B. „EFFECT OF EFFERVESCENCE IN COMBINATION WITH SUPERDISINTEGRANTS IN THE FORMULATION OF PROPRANOLOL HCL ORAL DISINTEGRATING TABLETS“. Asian Journal of Pharmaceutical and Clinical Research 10, Nr. 3 (01.03.2017): 227. http://dx.doi.org/10.22159/ajpcr.2017.v10i3.16096.

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ABSTRACTObjective: The current research work is intended to formulate propranolol HCl (PLH) as orally disintegrating tablet (ODT). It is also intending to checkthe superiority in a combination of superdisintegrants and effervescent mixture than the use of superdisintegrants alone by a direct compressiontechnique. To fasten the onset of action and thereby enhancing the bioavailability of PLH in comparison to its conventional tablets.Methods: Standard calibration curve of PLH was obtained in pH 6.8 phosphate buffer by spectrophotometric method, drug-excipient compatibilitystudies were carried by Fourier transform infrared (FT-IR) studies. All the formulations were evaluated for pre and postcompression studies.Accelerated stability studies were carried out up to 6 months for the optimized formulation, EF3.Results and Discussion: Superdisintegrants used in the study are compatible with PLH. Pre- and post-compression parameters were within theacceptable limits for all formulations. In vitro dissolution kinetic studies indicate the release of PLH from ODT increases as the concentration ofsuperdisintegrants as well as the ratio of citric acid: NaHCO3 of effervescent mixture increases. Formulations with an effervescent mixture are havingrapid disintegration and dissolution rate when compared to the formulations with superdisintegrants alone. The order of superdisintegrants inenhancing the dissolution rate of PLH is crospovidone (CPV) > croscarmellose sodium (CCS) > sodium starch glycolate (SSG). Formulation, EF3 (10%CPV and 1:3, citric acid: NaHCO3 ratio, respectively) had the highest dissolution efficiency at 10 minutes (DE10=82.74%); the first order dissolutionrate constant (K1=0.141/minutes) with a regression coefficient (r2=0.974) and lesser time for 90% of drug release (t90=4 minutes), was considered asthe optimal ODT in this study. Formulation EF3, passed the test for stability.Conclusion: Hence, an effective PLH ODT was formulated by the direct compression technique with disintegration by combination of superdisintegrantsand effervescent mixture, will fasten the onset of action and enhances the bioavailability of PLH in comparison to its conventional tablets.Keywords: Propranolol HCl, Orally disintegrating tablet, Sodium starch glycolate, Croscarmellose sodium, Crospovidone, Direct compression, In vitrodissolution studies.

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Ittadwar, Parul A., und Prashant k. Puranik. „Formulation and Evaluation of Gastro-retentive Drug Delivery System of Novel Famotidine Phospholipid Complex“. International Journal of Pharmaceutical Sciences and Drug Research 15, Nr. 03 (30.06.2023): 250–59. http://dx.doi.org/10.25004/ijpsdr.2023.150304.

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Famotidine is an H2 receptor antagonist belonging to the BCS Class II, characterized by low solubility and limited oral bioavailability. The current study encompasses the formulation of novel famotidine phospholipid complex (FHC) with the aid of design of experiments (Central Composite Design) using solvent evaporation technique to overcome the disadvantages of Famotidine. To further enhance the physicochemical properties of FHC, it was incorporated into gastro-retentive floating tablets (GRDDS) using direct compression technique with sodium bicarbonate as a gas generating agent and its properties were compared to famotidine floating tablets. The pre-compression parameters, namely bulk density, tapped density, Hausner’s ratio, Carr’s compressibility index and angle of repose were evaluated. The flow properties of FHC granules were found to be better than the plain famotidine granules. The postcompression parameters, namely thickness, hardness, friability, weight variation, drug content and swelling index showed better results for FHC as compared to famotidine floating tablets. In-vitro buoyancy study indicated that the floating lag time for FHC tablets (110 ± 0.021 seconds) was higher than famotidine tablets (36 ± 0.033 seconds) owing to the higher molecular weight of phosphatidylcholine. But the total floating time for FHC tablets was found to be more than 18 hours and for famotidine tablets it was ~12 hours, indicating the improved residence time and buoyancy. The in-vitro dissolution study depicted that the cumulative release for FHC tablets (99.84 ± 0.058%) was enhanced 1.07 fold than Famotidine tablets (92.73 ± 0.028%) and 1.6 fold than marketed tablet, Famocid (62.24 ± 0.023%). When kinetic modeling was performed, famotidine tablet followed zero order kinetics, whereas FHC tablet followed Higuchi model indicating a modified and sustained release pattern. The statistical analysis for %cumulative release performed using ANOVA and Dunnett’s test showed the p-value to be below 0.05 (0.0043) indicating that the analysis model was significant. An accelerated stability study was performed for a period of 6 months at 25 ± 2°C; 60 ± 5% RH. FHC tablets showed a better stability profile than famotidine tablets. In conclusion, FHC gastro-retentive floating tablets showed improved flow properties, post compression properties, better drug content, improved in-vitro buoyancy and enhanced cumulative release and stability profile.

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LoPachin, Richard M., Christopher L. Gaughan, Ellen J. Lehning, Yoshiro Kaneko, Thomas M. Kelly und Andrew Blight. „Experimental Spinal Cord Injury: Spatiotemporal Characterization of Elemental Concentrations and Water Contents in Axons and Neuroglia“. Journal of Neurophysiology 82, Nr. 5 (01.11.1999): 2143–53. http://dx.doi.org/10.1152/jn.1999.82.5.2143.

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To examine the role of axonal ion deregulation in acute spinal cord injury (SCI), white matter strips from guinea pig spinal cord were incubated in vitro and were subjected to graded focal compression injury. At several postinjury times, spinal segments were removed from incubation and rapidly frozen. X-ray microanalysis was used to measure percent water and dry weight elemental concentrations (mmol/kg) of Na, P, Cl, K, Ca, and Mg in selected morphological compartments of myelinated axons and neuroglia from spinal cord cryosections. As an index of axon function, compound action potentials (CAP) were measured before compression and at several times thereafter. Axons and mitochondria in epicenter of severely compressed spinal segments exhibited early (5 min) increases in mean Na and decreases in K and Mg concentrations. These elemental changes were correlated to a significant reduction in CAP amplitude. At later postcompression times (15 and 60 min), elemental changes progressed and were accompanied by alterations in compartmental water content and increases in mean Ca. Swollen axons were evident at all postinjury times and were characterized by marked element and water deregulation. Neuroglia and myelin in severely injured epicenter also exhibited significant disruptions. In shoulder areas (adjacent to epicenter) of severely injured spinal strips, axons and mitochondria exhibited modest increases in mean Na in conjunction with decreases in K, Mg, and water content. Following moderate compression injury to spinal strips, epicenter axons exhibited early (10 min postinjury) element and water deregulation that eventually recovered to near control values (60 min postinjury). Na+ channel blockade by tetrodotoxin (TTX, 1 μM) perfusion initiated 5 min after severe crush diminished both K loss and the accumulation of Na, Cl, and Ca in epicenter axons and neuroglia, whereas in shoulder regions TTX perfusion completely prevented subcellular elemental deregulation. TTX perfusion also reduced Na entry in swollen axons but did not affect K loss or Ca gain. Thus graded compression injury of spinal cord produced subcellular elemental deregulation in axons and neuroglia that correlated with the onset of impaired electrophysiological function and neuropathological alterations. This suggests that the mechanism of acute SCI-induced structural and functional deficits are mediated by disruption of subcellular ion distribution. The ability of TTX to reduce elemental deregulation in compression-injured axons and neuroglia implicates a significant pathophysiological role for Na+ influx in SCI and suggests Na+ channel blockade as a pharmacotherapeutic strategy.

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Schwartz, T. M., und R. K. Schwartz. „Paleogene postcompressional intermontane basin evolution along the frontal Cordilleran fold-and-thrust belt of southwestern Montana“. Geological Society of America Bulletin 125, Nr. 5-6 (22.02.2013): 961–84. http://dx.doi.org/10.1130/b30766.1.

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Al Hagbani, Turki, und Sami Nazzal. „Development of postcompressional textural tests to evaluate the mechanical properties of medicated chewing gum tablets with high drug loadings“. Journal of Texture Studies 49, Nr. 1 (15.08.2017): 30–37. http://dx.doi.org/10.1111/jtxs.12287.

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Rao.S, Kameswara, Yusuf MD., Saraswathi P., Ch R. Raghavendra Rao, Murali P. und Vijayakumar V. „Formulation and evaluation of orodispersible Enalapril maleate tablets: a comparative study on natural super disintegrents and synthetic super disintegrents“. International Journal of Advances in Scientific Research 1, Nr. 7 (03.09.2015): 313. http://dx.doi.org/10.7439/ijasr.v1i7.1821.

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The aim of the present investigation is to formulate Enalapril maleate oral disintegrating tablet by using natural and synthetic superdisintegrents..ODTs may also be used to deliver drugs to the oral cavity, for local action or, in some cases, absorption across the oral mucosa, thereby avoiding first-pass hepatic metabolism and potentially increasing the rate and extent of uptake, and reducing undesirable metabolites. The objectives of the research work is to formulate oral disintegrating tablets of Enalapril maleate by using different super disintegrates(Natural, Synthetic) in different ratio by direct compression technique and tablets were evaluated for precompressional and postcompressional Parameters such as angle of repose, bulk density, tapped density, compressibility index, drug content and in-vitro drug release study, hardness, friability, wetting time and invitro dispersion time. To study the physical characteristics of the individual drug and optimized formulations by FTIR spectroscopy. To evaluate various characteristics of the resulting tablets. Formulation CCS3, IH2 were subjected to stability Studies as per ICHguidelines at temperatures and humidity of 255C/605%RH; and 405C/755%RH.Tablets didnt reveal any appreciable changes in respect to hardness, disintegration time, drug content and dissolution profile.

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Vijayalaxmi, Sepuri, und Abbaraju Krishna Sailaja. „Design, Formulation, and Optimization of Nicardipine-Loaded Gastroretentive Floating Microspheres: In-vitro, Ex-vivo and In-vivo Characterization.“ INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 14, Nr. 03 (25.09.2024): 1652–60. http://dx.doi.org/10.25258/ijddt.14.3.57.

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Nicardipine hydrochloride is highly soluble at low pH values. The objective of this investigation was to design, manufacture, and refine the drug’s floating microspheres to increase its bioavailability and prolong its period of residence in the gastrointestinal tract. To optimize the Box-Behken and prepare the floating microspheres, solvent evaporation was employed. The formulation F5 was discovered to be the best as anticipated by the design expert software’s point prediction. Evaluations of pre- and postcompressional parameters were conducted. Utilizing several kinetic models, the drug release pathways were examined. The drugs and excipients did not interact, according to the FTIR/DSC investigations. According to the radiological approach, F5 showed good in-vitro buoyancy. The gastroretentive property of microspheres is revealed by X-ray pictures obtained at 2, 8, and 12 hours for the buoyancy investigation. F5 (235.04%) demonstrated a high relative bioavailability over oral tablets, according to the in-vivo pharmacokinetic investigation. In comparison to the marketed formulation group, the F5-treated group experienced a considerably larger percent decline in BP values (20.00 ± 6.00 and 13.00 ± 4.00%, respectively) at 36 and 48 hours of the in-vivo pharmacodynamic testing. For 90 days, the F5 formulation was maintained at 5 ± 2 and 25 ± 2°C, indicating the stability of nicardipine microspheres.

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Singh, Sudarshan, Dharmesh Savaliya, Suresh Shah D. und Sunil Bothara B. „Development and In vivo Bioavailability Evaluation of Sumatriptan Succinate Buccal Tablets“. International Journal of Pharmaceutical Sciences and Nanotechnology 7, Nr. 2 (31.05.2014): 2477–86. http://dx.doi.org/10.37285/ijpsn.2014.7.2.9.

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In the present investigation an attempt has made to design mucoadhesive buccal tablets of sumatriptan succinate to improve its bioavailability. The mucoadhesive buccal tablets were prepared by wet granulation procedure using different concentration of polycarbophil and hydroxy propyl methyl cellulose K4M alone. Compatibility study of drug and polymer were performed by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Precompression property of sumatriptan succinate was evaluated to check the suitability of compression method. Postcompressional parameters such as weight variation, hardness, thickness, surface pH, in vitro drug release, ex vivo bioadhesion time, ex vivo mucoadhesive strength, ex vivo permeation study and in vivo bioavailability study of optimized formulation were evaluated. FTIR spectroscopy and DSC study revealed that there was no possible interaction between drug and polymers, because no major change in peaks were obtained. The precompression parameters were in acceptable range of pharmacopoeial specification. The surface pH of the tablets was in the range of salivary pH (6.5 to 7.5) and tablets showed good ex vivo bioadhesion time up to 10 hr which indicated good adhesive capacity of tablets. The in vitro release of optimized formulation obeyed zero order kinetics with non-Fickian anomalous diffusion mechanism. The percentage relative bioavailability of sumatriptan succinate from optimized buccal tablets was found to be 152.76 %. Buccal tablets of sumatriptan succinate were successfully prepared with improved bioavailability.

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Edwards, M. R., N. M. Fasano, A. M. Giakas, M. M. Wang, J. Griff-McMahon, A. Morozov, V. M. Perez-Ramirez, N. Lemos, P. Michel und J. M. Mikhailova. „Greater than Five-Order-of-Magnitude Postcompression Temporal Contrast Improvement with an Ionization Plasma Grating“. Physical Review Letters 133, Nr. 15 (08.10.2024). http://dx.doi.org/10.1103/physrevlett.133.155101.

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47

Ran, Qiandong, Hao Li, Wonkeun Chang und QiJie Wang. „Self‐Compression of High Energy Ultrashort Laser Pulses“. Laser & Photonics Reviews, 08.12.2023. http://dx.doi.org/10.1002/lpor.202300595.

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AbstractNonlinear pulse compression techniques have been applied widely in the pursuit of ultra‐intense laser pulse with extremely high pulse energy (≈mJ) and extremely short pulse duration (≈sub‐10 fs). Although postcompression techniques using dispersive gratings or chirped mirrors have achieved 1 TW few‐cycle pulses, further increasing of the pulse intensity is limited by the damage threshold of dispersive optics, especially when self‐focusing and ionization in the propagation medium are considered. To overcome such limitations, ultrashort pulses self‐compression techniques without vulnerable dispersive optics have been explored in the past two decades. In this paper, the latest advances in these techniques will be reviewed with a discussion on the progress of various experimental approaches as well as their potential applications and roles in generating extremely intense optical fields for strong‐field physics research.

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Tsai, Ming-Shian, An-Yuan Liang, Chia-Lun Tsai, Po-Wei Lai, Ming-Wei Lin und Ming-Chang Chen. „Nonlinear compression toward high-energy single-cycle pulses by cascaded focus and compression“. Science Advances 8, Nr. 31 (05.08.2022). http://dx.doi.org/10.1126/sciadv.abo1945.

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The advancement of contemporary ultrafast science requires reliable sources to provide high-energy few-cycle light pulses. Through experiments and simulations, we demonstrate an arrangement of pulse postcompression, referred to as cascaded focus and compression (CASCADE), for generating millijoule-level, single-cycle pulses in a compact fashion. CASCADE is realized by a series of foci in matter, whereas pulse compression is provided immediately after each focus to maintain a high efficiency of spectral broadening. By implementing four stages of CASCADE in argon cells, we achieve 50-fold compression of millijoule-level pulses at 1030 nanometers from 157 to 3.1 femtoseconds, with an output pulse energy of 0.98 millijoules and a transmission efficiency of 73%. When driving high harmonic generation, these single-cycle pulses enable the creation of a carrier-envelope phase-dependent extreme ultraviolet continuum with energies extending up to 180 electron volts, providing isolated attosecond pulses at the output.

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Horný, V., P. G. Bleotu, D. Ursescu, V. Malka und P. Tomassini. „Efficient laser wakefield accelerator in pump depletion dominated bubble regime“. Physical Review E 110, Nr. 3 (06.09.2024). http://dx.doi.org/10.1103/physreve.110.035202.

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With the usage of the postcompression technique, few-cycle joule-class laser pulses are nowadays available extending the state of the art of 100 TW-class laser working at 10 Hz repetition. In this Letter, we explore the potential of wakefield acceleration when driven with such pulses. The numerical modeling predicts that 50% of the laser pulse energy can be transferred into electrons with energy above 15 MeV, and with charge exceeding several nanocoulombs for the electrons at hundreds of MeV energy. In such a regime, the laser pulse depletes its energy to plasma rapidly driving a strong cavitated wakefield. The self-steepening effect induces a continuous prolongation of a bubble resulting in a massive continuous self-injection that explains the extremely high charge of the beam rending this approach suitable for promoting Bremsstrahlung emitter and generator of tertiary particles, including neutrons released through photonuclear reactions. Published by the American Physical Society 2024

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Burke, R. D., P. Olmeda und J. R. Serrano. „Dynamic Identification of Thermodynamic Parameters for Turbocharger Compressor Models“. Journal of Engineering for Gas Turbines and Power 137, Nr. 10 (01.10.2015). http://dx.doi.org/10.1115/1.4030092.

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A novel experimental procedure is presented which allows simultaneous identification of heat and work transfer parameters for turbocharger compressor models. The method introduces a thermally transient condition and uses temperature measurements to extract the adiabatic efficiency and internal convective heat transfer coefficient simultaneously, thus capturing the aerodynamic and thermal performance. The procedure has been implemented both in simulation and experimentally on a typical turbocharger gas stand facility. Under ideal conditions, the new identification predicted adiabatic efficiency to within 1% point1 and heat transfer coefficient to within 1%. A sensitivity study subsequently showed that the method is particularly sensitive to the assumptions of heat transfer distribution pre- and postcompression. If 20% of the internal area of the compressor housing is exposed to the low pressure intake gas, and this is not correctly assumed in the identification process, errors of 7–15% points were observed for compressor efficiency. This distribution in heat transfer also affected the accuracy of heat transfer coefficient which increased to 20%. Thermocouple sensors affect the transient temperature measurements and in order to maintain efficiency errors below 1%, probes with diameter of less than 1.5 mm should be used. Experimentally, the method was shown to reduce the adiabatic efficiency error at 90 krpm and 110 krpm compared to industry-standard approach from 6% to 3%. However at low speeds, where temperature differences during the identification are small, the method showed much larger errors.

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