Добірка наукової літератури з теми "Β-reach"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Β-reach".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "Β-reach":
1
Wang, Zhi Meng, Hong Wei Xie, Cai Ling Liu та Yu Chun Zhai. "The Effect of Li2O Content on the Electrochemical Performance of β (β′′)-Al2O3". Advanced Materials Research 1004-1005 (серпень 2014): 371–75. http://dx.doi.org/10.4028/www.scientific.net/amr.1004-1005.371.
Анотація:
The β (β′′)-Al2O3powder is prepared by solid phase reaction method, which is sintered inside the powder in MoSi2electric resistance furnace at 1600°C after isostatic pressing. The experimental result shows that the addition of Li2O can greatly decrease the resistivity of β (β′′)-Al2O3electrolyte and when the mass fraction of Li2O is 0.8~0.9%, the resistivity of β (β′′)-Al2O3electrolyte can reach 4~5(Ω•cm)-1.
2
Filtser, Arnold, and Omrit Filtser. "Condorcet Relaxation In Spatial Voting." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 6 (May 18, 2021): 5407–14. http://dx.doi.org/10.1609/aaai.v35i6.16681.
Анотація:
Consider a set of voters V, represented by a multiset in a metric space (X,d). The voters have to reach a decision - a point in X. A choice p∈ X is called a β-plurality point for V, if for any other choice q∈ X it holds that |{v∈ V ∣ β⋅ d(p,v)≤ d(q,v)}| ≥|V|/2 . In other words, at least half of the voters ``prefer'' over q, when an extra factor of β is taken in favor of p. For β=1, this is equivalent to Condorcet winner, which rarely exists. The concept of β-plurality was suggested by Aronov, de Berg, Gudmundsson, and Horton [SoCG 2020] as a relaxation of the Condorcet criterion. Denote by β*(X,d) the value sup{ β ∣ every finite multiset V in X admits a β-plurality point}}. The parameter β* determines the amount of relaxation required in order to reach a stable decision. Aronov et al. showed that for the Euclidean plane β*(ℝ2,\|⋅\|2)=√3/2 , and more generally, for d-dimensional Euclidean space, 1/√d ≤ β*(ℝd,\|⋅\|2)≤√3/2 . In this paper, we show that 0.557≤ β*(ℝd,\|⋅\|2) for any dimension d (notice that 1/√d
3
Rigolin, S. "Physics reach of β-beams and ν-factories: the problem of degeneracies". Nuclear Physics B - Proceedings Supplements 155, № 1 (травень 2006): 33–37. http://dx.doi.org/10.1016/j.nuclphysbps.2006.02.006.
4
Chiang, Hsiu-Hsi, Po-Fu Lee, Yun-Tsung Chen, Chi-Fang Lin, Shu Xu, Yi-Tien Lin, Yu-Ting Lin, et al. "Low Cardiorespiratory Fitness, Muscular Fitness, and Flexibility Are Associated with Body Fat Distribution and Obesity Risk Using Bioelectrical Impedance in Taiwanese Adults." International Journal of Environmental Research and Public Health 19, no. 14 (July 21, 2022): 8858. http://dx.doi.org/10.3390/ijerph19148858.
Анотація:
In terms of public health, obesity and overweight have become major concerns worldwide. Nevertheless, regarding body composition, it is important to have a more precise understanding of the fat-to-muscle ratio. Hence, this study aimed to adopt bioelectrical impedance measurements to test body fat percentage (BF%) and to determine the associations between health-related physical fitness and both body fat (BF) distribution and BF obesity risk in Taiwanese adults. We conducted a cross-sectional study and reviewed data derived from Taiwan’s Scientific Physical Fitness Survey. From the database, responses from 17,970 participants aged 23–64 years were collected in this study. Each participant completed a series of health-related physical fitness measurements, including cardiorespiratory fitness (3 min of a progressive knee-up and step (3MPKS) test), muscular fitness (hand-grip strength), and flexibility (sit-and-reach test). The BF% of each participant was assessed using the bioelectrical impedance analysis method. BF% was negatively associated with low performance on the 3MPKS (β = 11.314, p < 0.0001 for men; β = 12.308, p < 0.0001 for women), hand-grip strength (β = 2.071, p < 0.0001 for men; β = 0.859, p < 0.0001 for women), and sit-and-reach (β = 0.337, p = 0.008 for women) tests but was positively associated with sit-and-reach (β = −0.394, p = 0.004 for men). A risk of BF obesity for low performance of 3MPKS (odds ratio (OR) = 26.554, p < 0.0001 for men; OR = 25.808, p < 0.0001 for women), hand-grip strength (OR = 1.682, p < 0.0001 for men; OR = 1.234, p < 0.0001 for women), and sit-and-reach (OR = 1.142, p = 0.007 for women) tests was observed. These results suggest that low levels of cardiorespiratory fitness, muscular fitness, and flexibility are associated with an increased risk of BF obesity.
5
Larwood, John, та Paul Kalas. "A stellar fly-by simulation giving β Pic's disc asymmetries". Symposium - International Astronomical Union 202 (2004): 353–55. http://dx.doi.org/10.1017/s0074180900218238.
Анотація:
We have numerically investigated the dynamics of how a close stellar fly-by encounter of a symmetrical circumstellar planetesimal disc can give rise to the many kinds of asymmetries and substructures attributed to the dusty disc of β Pic. We find three recognizable groupings of test particles that can be related to the morphology of the β Pic disc. These are: highly eccentric and inclined orbit particles that reach apocentre in the southwest, moderately eccentric and inclined orbit particles that reach apocentre in the northeast, and a relatively unperturbed region inside ∽200 AU radius.
6
Chen, Jie, De Fang Dai, Xiu Ling Gu та Lin Yuan. "Screening and Identification of β-Glucosidase Producing Strain of Fusarium Oxysporum". Advanced Materials Research 652-654 (січень 2013): 402–5. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.402.
Анотація:
Five strains, which can produce β-glucosidase, were screened out from 96 strains isolated from linseed from different regions in China. Based on morphological features and internal transcribed spacer (ITS) sequence analysis, the five strains were all determined as Fusarium oxysporum. The strain named as S15 produces the highest β-glucosidase, which activity reach at 13.58 U/mL.
7
Saillour-Glénisson, Florence, Karine Nouette-Gaulain, Vianney Jouhet, Louis-Rachid Salmi, and Aurélie Petit-Monéger. "Comparing Graphical Formats for Feedback of Clinical Practice Data." Methods of Information in Medicine 56, no. 01 (2017): 28–36. http://dx.doi.org/10.3414/me15-01-0163.
Анотація:
Summary Objectives: Although graphical formats used to feedback clinical practice data may have an important impact, the most effective formats remain unknown. Using prevention of postoperative nausea and vomiting by anesthesiologists as an application, the objective of this study was to assess which graphical formats for feedback of clinical practice data are the most incentive to change practice. Methods: We conducted a multicenter cross-sectional study among anesthesiologists randomized in two groups between March andJune 2014. Each anesthesiologist assessed 15 graphical formats displaying an indicator of either prescription conformity or prescription effectiveness. Graphical formats varied by: type of graph (bar charts, linear sliders, or pictographs), presence or not of a target to reach, presence or not of a contrast between a hypothetical physician and his/her team, direction of the difference between the physician and his/her team, and restitution or not of the quality indicator evolution over the previous six months. The primary outcome was a numerical scale score expressing the anesthesiologists’ motivation to change his/her practice (ranging from 1 to 10 points). A linear mixed model was fitted to explain variation in motivation. Results: Sixty-six anesthesiologists assessed the conformity indicator and 67 assessed the effectiveness indicator. Factors associated with an increased motivation to change practice were: (i) presence of a clearly defined target to reach (conformity: β = 0.24 points, p = 0.0046; effectiveness: β = 1.11 points, p < 0.0001); (ii) contrast between the physician and his/her team (conformity: β = 0.38 points, p < 0.0001; effectiveness: β = 0.33 points, p = 0.0021); (iii) better results for the team than for the physician (conformity: β = 0.65 points, p < 0.0001; effectiveness β = 1.16 points, p < 0.0001). For the effectiveness indicator, anesthesiologists were more motivated to change practice with bar charts (β = 0.24 points, p = 0.0447) and pictographs (β = 0.45 points, p = 0.0001) than with linear sliders. Conclusions: Graphs associated with a defined target to reach should be preferred to deliver feedback, especially bar graphs or pictographs for indicators which are more complex to represent such as effectiveness indicators. Anesthesiologists are also more motivated to change practice when graphs report contrasted data between the physician and his/her team and a lower conformity or effectiveness for the physician than for his/her team.
8
Yang, Jin Song, Rui Yang, and Hai Sheng Tan. "Research on the Inclusion Complex of Astaxanthin." Advanced Materials Research 468-471 (February 2012): 2777–84. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.2777.
Анотація:
Taking β-cyclotextrin and gelatin as wall materials, study of inclusion was processed on astaxanthin. It was shown in the study that β-cyclotextrin and gelatin at the ratio of 4 to 1 was found to be the best wall material for inclusion complex. The optimal conditions of inclusion were established by the RSM experiment: when the amount of wall material was 0.4 g/g yeast, temperature 40°C, time 1.2 h, the inclusion rate could reach 81.03%. The characterization of the inclusion complex was confirmed by different temperatures and light, the result shows that the inclusion complex could improve the stability of astaxanthin. The inclusion complex was stored in dark at 4°C for 60 days, the residual rate of astaxathin could reach 95% and more stable than that before inclusion by 35%.
9
HOU, Q. R., B. F. GU, Y. B. CHEN, and Y. J. HE. "PHONON-DRAG EFFECT OF ULTRA-THIN FeSi2 AND MnSi1.7/FeSi2 FILMS." Modern Physics Letters B 25, no. 22 (August 30, 2011): 1829–38. http://dx.doi.org/10.1142/s0217984911027078.
Анотація:
Phonon-drag effect usually occurs in single crystals at very low temperatures (10–200 K). Strong phonon-drag effect is observed in ultra-thin β- FeSi 2 films at around room temperature. The Seebeck coefficient of a 23 nm-thick β- FeSi 2 film can reach -1.375 mV/K at 343 K. However, the thermoelectric power factor of the film is still small, only 0.42×10-3 W/m-K2, due to its large electrical resistivity. When a 27 nm-thick MnSi 1.7 film with low electrical resistivity is grown on it, the thermoelectric power factor of the MnSi 1.7 film can reach 1.5×10-3 W/m-K2 at around room temperature. This value is larger than that of bulk MnSi 1.7 material in the same temperature range.
10
Yuan, Xiao Jing, Bai Lin Zha та Han Gong Wang. "Dielectric and Infrared Properties of Plasma Sprayed Nano β-SiC/ Al2O3 Agglomerate Composite Absorbing Coatings". Advanced Materials Research 634-638 (січень 2013): 1901–5. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.1901.
Анотація:
In this paper, the nano-β-SiC/Al2O3 composite absorbing coatings produced by plasma spraying technology were reported. Where, β-SiC phase dissipates in the boundary of Al2O3 grains. Then, the relationship between microstructure and dielectric properties was built. Some results are shown as follows: with increasing of flatten ratio of particle and pores, the microwave reflectivity coefficient of composite absorbing coatings decreases and ranges to low frequency. And, there exists a threshold value, about 30wt% of nano β-SiC, the microwave reflectivity coefficient of composite absorbing coatings can reach to -8 dB. The infrared properties of β-SiC/ Al2O3composite absorbing coatings with experiment is about 0.6~0.8, respectively.
Дисертації з теми "Β-reach":
1
Marchal, Cathie. "Développement de méthodes analytiques pour la caractérisaton de lots industriels du nitroxyde SG1." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4767.
Анотація:
Ce travail de thèse s’inscrit dans un contexte industriel. Il consiste en la caractérisation de lots bruts de SG1 : le N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle. La spécificité de cette espèce est son caractère radicalaire stable. La première partie de ce travail consistait à développer une méthode d’analyse, facilement applicable en laboratoire d’analyse de contrôle sur site industriel pour la caractérisation de la pureté en SG1 dans des lots synthétisés. La méthode choisie a été développée par chromatographie liquide haute performance (HPLC). Pour ce faire, un étalon de SG1 a été préparé par purification de SG1 brut industriel en utilisant la technique séparative chromatographique de partage centrifuge (CPC). L’identification des impuretés suspectées majoritaires dans les lots de SG1 bruts a ensuite été réalisée par spectroscopie RMN ou par l’étude des fragments obtenus par spectrométrie de masse en tandem par ionisation electrospray. A l’aide de ces techniques, quinze impuretés majori- taires ont été identifiées. Des méthodes de quantification ont ensuite été développées pour douze de ces impuretés par diverses techniques analytiques chromatographiques : par HPLC-UV, HPLC-MS ou GC-MS ou par des techniques spectroscopiques Infra-Rouge ou encore par conductimétrieThis PhD study has been carried out within an industrial context. It deals with the characterization of industrial batches of N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle also called SG1. The distinctive feature of this molecule lies in its specific stability which is uncommon for radical species. The first part of this study consists in developping an analytical method, easy to implement in a QC laboratory for the determination of SG1 purity. The chosen analytical method has been developped by High Performances Liquid Chromatography (HPLC). This method requires the use of a standard sample of SG1, which has been obtained after purification of industrial batches of SG1 by the use of an innovative separative technology, the Centrifugal Partition Chromatography (CPC). The identification of the impurities, suspected as the major impurities in the industrial batches of SG1, has been carried out by NMR spectroscopy or by the study of their fragmentation observed by Tandem Mass Spectrometry – Electrospray Ionization. The use of these techniques enabled the identification of fifteen major impurities. Quantification methods by various techniques (HPLC-UV, HPLC-MS, GC-MS, other direct spectroscopic techniques like Infra-Red or other types of techniques like conductimetry) have been developped for twelve impurities
2
Cotsakis, Ryan. "Sur la géométrie des ensembles d'excursion : garanties théoriques et computationnelles." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5007.
Анотація:
L'ensemble d'excursion EX(u) d'un champ aléatoire réel X sur R^d à un niveau de seuil u ∈ R est le sous-ensemble du domaine R^d où X dépasse u. Ainsi, l'ensemble d'excursion est aléatoire, et sa distribution à un niveau fixe u est déterminée par la distribution de X. Étant des sous-ensembles de R^d, les ensembles d'excursions peuvent être étudiés en termes de leurs propriétés géométriques comme moyen d'obtenir des informations partielles sur les propriétés de distribution des champs aléatoires sous-jacents.Cette thèse examine :(a) comment les mesures géométriques d'un ensemble d'excursion peuvent être déduites à partir d'un échantillon discret de l'ensemble d'excursion, et(b) comment ces mesures peuvent être liées aux propriétés distributionnelles du champ aléatoire à partir duquel l'ensemble d'excursion a été obtenu. Chacun de ces points est examiné en détail dans le Chapitre 1, qui fournit un aperçu global des résultats trouvés tout au long du reste de ce manuscrit. Les mesures géométriques que nous étudions (pour les ensembles d'excursion et les sous-ensembles déterministes de R^d) lors de l'adressage du point (a) sont la mesure de la surface de dimension (d−1), le reach, et le rayon de r-convexité. Chacune de ces quantités peut être liée à la régularité de la frontière de l'ensemble, ce qui est souvent difficile à déduire à partir d'échantillons discrets de points.Pour résoudre ce problème, nous apportons les contributions suivantes au domaine de la géométrie computationnelle :- Dans le Chapitre 2, nous identifions le facteur de biais qui correspond aux algorithmes de comptage local pour calculer la mesure de la surface de dimension (d − 1) des ensembles d'excursion sur une grande classe de pavages de R^d. Le facteur de biais dépend uniquement de la dimension d et non de la géométrie précise du pavage.- Dans le Chapitre 3, nous introduisons un algorithme de comptage pseudo-local pour calculer le périmètre des ensembles d'excursion en deux dimensions. L'algorithme proposé est convergent multigrille (multigrid convergent en anglais) et comporte un hyper paramètre réglable pouvant être choisi automatiquement à partir d'informations accessibles.- Dans le Chapitre 4, nous introduisons le β-reach en tant que généralisation du reach, et l'utilisons pour prouver la cohérence d'un estimateur du reach des sous-ensembles fermés de R^d. De même, nous définissons un estimateur cohérent du rayon de r-convexité des sous-ensembles fermés de R^d. De nouvelles relations théoriques sont établies entre le reach et le rayon de r-convexité. Nous étudions également comment ces mesures géométriques des ensembles d'excursion sont liées à la distribution du champ aléatoire.- Dans le Chapitre 5, nous introduisons l'extremal range : une statistique géométrique locale qui caractérise l'étendue spatiale des dépassements de seuil à un niveau fixe u ∈ R. La distribution de l'extremal range est entièrement déterminée par la distribution de l'ensemble d'excursion au niveau u. Nous montrons comment l'extremal range est liée distributionnellement aux volumes intrinsèques de l'ensemble d'excursion. De plus, le comportement limite de l'extremal range aux grands seuils est étudié en relation avec la stabilité des peaks-over-threshold du champ aléatoire sous-jacent. Enfin, la théorie est appliquée à des données climatiques réelles pour mesurer le degré d'indépendance asymptotique présent et sa variation dans l'espace.Des perspectives sur la manière dont ces résultats peuvent être améliorés et étendus sont fournies dans le Chapitre 6The excursion set EX(u) of a real-valued random field X on R^d at a threshold level u ∈ R is the subset of the domain R^d on which X exceeds u. Thus, the excursion set is random, and its distribution at a fixed level u is determined by the distribution of X. Being subsets of R^d, excursion sets can be studied in terms of their geometrical properties as a means of obtaining partial information about the distributional properties of the underlying random fields.This thesis investigates(a) how the geometric measures of an excursion set can be inferred from a discrete sample of the excursion set, and(b) how these measures can be related back to the distributional properties of the random field from which the excursion set was obtained.Each of these points are examined in detail in Chapter 1, which provides a broad overview of the results found throughout the remainder of this manuscript. The geometric measures that we study (for both excursion sets and deterministic subsets of R^d) when addressing point (a) are the (d − 1)-dimensional surface area measure, the reach, and the radius of r-convexity. Each of these quantities can be related to the smoothness of the boundary of the set, which is often difficult to infer from discrete samples of points. To address this problem, we make the following contributions to the field of computational geometry:• In Chapter 2, we identify the bias factor in using local counting algorithms for computing the (d − 1)-dimensional surface area of excursion sets over a large class of tessellations of R^d. The bias factor is seen to depend only on the dimension d and not on the precise geometry of the tessellation.• In Chapter 3, we introduce a pseudo-local counting algorithm for computing the perimeter of excursion sets in two-dimensions. The proposed algorithm is multigrid convergent, and features a tunable hyperparameter that can be chosen automatically from accessible information.• In Chapter 4, we introduce the β-reach as a generalization of the reach, and use it to prove the consistency of an estimator for the reach of closed subsets of R^d. Similarly, we define a consistent estimator for the radius of r-convexity of closed subsets of R^d. New theoretical relationships are established between the reach and the radius of r-convexity.We also study how these geometric measures of excursion sets relate to the distribution of the random field.• In Chapter 5, we introduce the extremal range: a local, geometric statistic that characterizes the spatial extent of threshold exceedances at a fixed level threshold u ∈ R. The distribution of the extremal range is completely determined by the distribution of the excursion set at the level u. We show how the extremal range is distributionally related to the intrinsic volumes of the excursion set. Moreover, the limiting behavior of the extremal range at large thresholds is studied in relation to the peaks-over-threshold stability of the underlying random field. Finally, the theory is applied to real climate data to measure the degree of asymptotic independence present, and its variation throughout space.Perspectives on how these results may be improved and expanded upon are provided in Chapter 6
3
Marchal, Cathie. "Développement de méthodes analytiques pour la caractérisaton de lots industriels du nitroxyde SG1." Electronic Thesis or Diss., Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4767.
Анотація:
Ce travail de thèse s’inscrit dans un contexte industriel. Il consiste en la caractérisation de lots bruts de SG1 : le N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle. La spécificité de cette espèce est son caractère radicalaire stable. La première partie de ce travail consistait à développer une méthode d’analyse, facilement applicable en laboratoire d’analyse de contrôle sur site industriel pour la caractérisation de la pureté en SG1 dans des lots synthétisés. La méthode choisie a été développée par chromatographie liquide haute performance (HPLC). Pour ce faire, un étalon de SG1 a été préparé par purification de SG1 brut industriel en utilisant la technique séparative chromatographique de partage centrifuge (CPC). L’identification des impuretés suspectées majoritaires dans les lots de SG1 bruts a ensuite été réalisée par spectroscopie RMN ou par l’étude des fragments obtenus par spectrométrie de masse en tandem par ionisation electrospray. A l’aide de ces techniques, quinze impuretés majori- taires ont été identifiées. Des méthodes de quantification ont ensuite été développées pour douze de ces impuretés par diverses techniques analytiques chromatographiques : par HPLC-UV, HPLC-MS ou GC-MS ou par des techniques spectroscopiques Infra-Rouge ou encore par conductimétrieThis PhD study has been carried out within an industrial context. It deals with the characterization of industrial batches of N-tert-butyl-N- (1-diethylphosphono-2,2-dimethylpropyl)-N-oxyle also called SG1. The distinctive feature of this molecule lies in its specific stability which is uncommon for radical species. The first part of this study consists in developping an analytical method, easy to implement in a QC laboratory for the determination of SG1 purity. The chosen analytical method has been developped by High Performances Liquid Chromatography (HPLC). This method requires the use of a standard sample of SG1, which has been obtained after purification of industrial batches of SG1 by the use of an innovative separative technology, the Centrifugal Partition Chromatography (CPC). The identification of the impurities, suspected as the major impurities in the industrial batches of SG1, has been carried out by NMR spectroscopy or by the study of their fragmentation observed by Tandem Mass Spectrometry – Electrospray Ionization. The use of these techniques enabled the identification of fifteen major impurities. Quantification methods by various techniques (HPLC-UV, HPLC-MS, GC-MS, other direct spectroscopic techniques like Infra-Red or other types of techniques like conductimetry) have been developped for twelve impurities
Частини книг з теми "Β-reach":
1
Thomas, Susan E. "Alkene synthesis (Peterson olefination)." In Organic Synthesis. Oxford University Press, 1991. http://dx.doi.org/10.1093/hesc/9780198557913.003.0010.
Анотація:
This chapter highlights the key compounds in the application of organosicilicon chemistry to the synthesis of alkenes: β-hydroxysilanes. It describes the three methods of generating them starting with the addition of α-metallated silanes to carbonyl compounds. α-Metallated silanes may be generated in several ways including addition of organometallic nucleophiles to vinylsilanes, deprotonation of α to silicon, and metal-halogen exchange. The chapter then investigates another method of generating β-hydroxysilanes: the addition of dialkylcuprates to α, β-epoxysilanes. α, β-epoxysilanes are readily synthesized by epoxidation of vinyl silanes. They react with organocuprate reagents in a regiospecific manner to give β-hydroxysilanes. Finally, the chapter elaborates on the last method of generating β-hydroxysilanes: the addition of hydride sources or organometallic reagents to β-ketosilanes. It also considers the conversion of β-hydroxysilanes into alkenes and some examples of silicon-based alkene synthesis.
2
Thomas, Susan E. "Alkene synthesis (Peterson olefination)." In Organic Synthesis. Oxford: Oxford University Press, 1991. http://dx.doi.org/10.1093/hesc/9780198556626.003.0010.
Анотація:
Abstract This chapter highlights the key compounds in the application of organosicilicon chemistry to the synthesis of alkenes: β-hydroxysilanes. It describes the three methods of generating them starting with the addition of α-metallated silanes to carbonyl compounds. α-Metallated silanes may be generated in several ways including addition of organometallic nucleophiles to vinylsilanes, deprotonation of α to silicon, and metal-halogen exchange. The chapter then investigates another method of generating β-hydroxysilanes: the addition of dialkylcuprates to α, β-epoxysilanes. α, β-epoxysilanes are readily synthesized by epoxidation of vinyl silanes. They react with organocuprate reagents in a regiospecific manner to give β-hydroxysilanes. Finally, the chapter elaborates on the last method of generating β-hydroxysilanes: the addition of hydride sources or organometallic reagents to β-ketosilanes. It also considers the conversion of β-hydroxysilanes into alkenes and some examples of silicon-based alkene synthesis.
3
Nassef, Mohamed, and Nashat Abdulhalim. "VA ECMO and drug intoxication." In Evolving Therapies and Technologies in Extracorporeal Membrane Oxygenation [Working Title]. IntechOpen, 2024. http://dx.doi.org/10.5772/intechopen.1005793.
Анотація:
ECMO support can help in maintaining tissue perfusion and oxygenation in acutely intoxicated patients until the drug or toxin is either eliminated by the body with natural metabolism and excretory processes or possibly renal replacement therapy may be instituted to enhance the elimination. Once cardiotoxic substances reach systemic circulation and are distributed in the various tissues, the patient is present with cardiovascular dysfunction, arrhythmia, or cardiovascular collapse. Cardiovascular collapse may require temporary support of the circulatory function. This helps in hepatic detoxification over time while providing reliable tissue perfusion and allowing sufficient antidote circulation. Extracorporeal membrane oxygenation (ECMO) use in cardiotoxic drug overdose is increasing. Calcium channel blockers (CCB) along with β-blockers constitute more than 65% of deaths from cardiovascular medications whereas in the 2021, American Association of Poison Control Centers’ National Poison Data System Annual report, Tricyclic Antidepressant (TCA) accounted for 4705 single exposures and 15 deaths. VA ECMO is effective in critically ill poisoned patients who do not respond to conventional therapies and did not show any improvement along with refractory shock and acute renal failure like in CCB drug overdose and TCA-induced cardiac toxicity and cardiogenic shock, where the recovery depends mainly on maintaining perfusion. The procedure is considered as a lifesaving bridge either to recovery, to antidote, to toxin elimination with renal replacement therapy, or to transplant.
4
Ibuka, Toshiro, and Yoshinori Yamamoto. "Boron trifluoride/aluminium trichloride-mediated conjugate addition and substitution reactions." In Organocopper Reagents: A Practical Approach, 143–58. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198557579.003.0007.
Анотація:
Abstract The conjugate addition and the substitution reactions of ordinary organo-copper reagents are the most important carbon–carbon bond-forming processes in synthetic organic chemistry today. However, owing to either moderate reactivity of the conventional organocopper reagents or severe steric hindrance in the substrates, the attempted conjugate addition to certain α,β-unsaturated carbonyl compounds or substitution to allylic and propargy-lic systems often gives none of the desired products. Failure to react with ordinary organocuprates has undoubtedly detracted from the application of organocopper reactions in synthesis.
5
Fleming, Ian. "Synthetic applications of silylcuprates and stannylcuprates." In Organocopper Reagents: A Practical Approach, 257–92. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198557579.003.0012.
Анотація:
Abstract Silylcopper and stannylcopper reagents and the corresponding cuprates react with many of the same substrates (Scheme 12.1) as their carbon-based counterparts. The products carry on their carbon framework a silyl or stannyl group, with which many transformations can be carried out, replacing these functional groups with carbon groups or with other functional groups. In addition, silylcuprates and stannylcuprates react with unactivated allenes to give vinyl or allyl derivatives depending upon the structure of the allene. In general, silylcopper and stannylcopper reagents and the corresponding cuprates appear to be thermodynamically more stable in THF solution than their carbon-based counterparts, allowing them to be treated with their substrates at temperatures of 0°C and above over several hours if necessary, although it rarely is, because they appear to be simultaneously kinetically more reactive than the carbon-based reagents, reacting with substrates such as allenes and α,β-unsaturated esters that carbon-based cuprates do not react with in the normal course of events.
6
Jones, John. "Enolate alkylations with alkyl halides." In Core Carbonyl Chemistry. Oxford University Press, 1997. http://dx.doi.org/10.1093/hesc/9780198559597.003.0008.
Анотація:
This chapter addresses enolate alkylations with alkyl halides. Simple enolates react irreversibly with soft (polarized) electrophiles such as methyl iodide. A new carbon–carbon bond is formed in an SN2, which is of considerable synthetic importance. The chapter then looks at enolates derived from simple ketones, simple esters, and β dicarbonyl compounds. If cyclohexanone is treated with ethanolic sodium ethoxide in the presence of methyl iodide, most of the latter reacts with ethoxide ion. However, if the considerably more hindered and slightly more basic t-butoxide is used as base, little reaction of it with the methyl iodide occurs. The difficulty arises from the fact that substantial concentrations of bases derived from alcohols are necessary to obtain even small concentrations of enolates from simple ketones.
7
Thomas, Susan E. "Allylsilanes and acylsilanes." In Organic Synthesis. Oxford University Press, 1991. http://dx.doi.org/10.1093/hesc/9780198557913.003.0012.
Анотація:
This chapter reviews some methods available for making allylsilanes. It focuses on the silylation of a metal-allyl species as the most direct method available for making them as well as the use of the Wittig reaction. Allylsilanes react with electrophiles at their γ carbon atom as attack at this position generates a carbocation β to silicon. Displacement of the silyl group subsequently produces a new alkene. The chapter then shifts to detail the method of synthesizing acylsilanes which involves deprotonation and silylation of the 1,3-derivative of an aldehyde. It considers how acylsilanes have been synthesized by several other approaches: a reverse Brook rearrangement (silyl-Wittig rearrangement) of allyltrimethylsilyl ether followed by oxidation and reductive cleavage of carbon-sulphur bonds in the silylenol ethers derived from thiol esters.
8
Thomas, Susan E. "Allylsilanes and acylsilanes." In Organic Synthesis. Oxford: Oxford University Press, 1991. http://dx.doi.org/10.1093/hesc/9780198556626.003.0012.
Анотація:
Abstract This chapter reviews some methods available for making allylsilanes. It focuses on the silylation of a metal-allyl species as the most direct method available for making them as well as the use of the Wittig reaction. Allylsilanes react with electrophiles at their γ carbon atom as attack at this position generates a carbocation β to silicon. Displacement of the silyl group subsequently produces a new alkene. The chapter then shifts to detail the method of synthesizing acylsilanes which involves deprotonation and silylation of the 1,3-derivative of an aldehyde. It considers how acylsilanes have been synthesized by several other approaches: a reverse Brook rearrangement (silyl-Wittig rearrangement) of allyltrimethylsilyl ether followed by oxidation and reductive cleavage of carbon-sulphur bonds in the silylenol ethers derived from thiol esters.
9
Weiskrantz, Lawrence. "Blindsight—Putting Beta (β) on the Back Burner." In Out of Mind, 20–33. Oxford University PressOxford, 2001. http://dx.doi.org/10.1093/oso/9780198506300.003.0002.
Анотація:
Abstract Blindsight is the capacity for making visual discriminations in the absence of acknowledged awareness, associated with damage to the visual cortex. Subjects can reach for briefly presented stimuli, can discriminate orientation, movement direction, wavelength, and so forth. In fact, the field has expanded recently. B. de Gelder and her colleagues have demonstrated discrimination of emotional expression of faces (1999; 2000). Robert Kentridge and colleagues (1999) have shown that an unseen cue in the blind field can direct attention to an unseen target. However, this subject is not reviewed here. Other relatively recent reviews are available (Weiskrantz, 1997, 1998; Cowey and Stoerig, 1991; Stoerig and Cowey, 1997), to which these latest references can be added. Instead this chapter concentrates on some of the logical issues involved in its demonstration and interpretation. Blindsight is an example of implicit processing. All examples of implicit processing in neuropsychology are, to varying degrees, counter-intuitive, and hence subject to sceptical attack, but perhaps blindsight is the most counter-intuitive of them all, and historically it has been questioned on fronts that are unique to it. The typical case of damage to V1 is unilateral, and hence there is an intact half-field of normal vision. Therefore doubts have been raised as to whether the ‘intact’ performance seen in the blind field genuinely originates from stimuli within it, but instead might be based on artefactual stimulation of the intact visual field—either because of stray light in the display environment or spread of light within the ocular media (Campion et al., 1983). This was a legitimate concern, but various stringent controls, e.g. use of the optic disc as a control, leave no doubt that blindsight can be processing of stimuli genuinely restricted to the blind field (review by Weiskrantz, 1998).
10
Taber, Douglass F. "The Carreira Synthesis of (±)-Gelsemoxonine." In Organic Synthesis. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190200794.003.0104.
Анотація:
The traditional Chinese pharmacopeia includes Gelsemium elegans benth, from which the alkaloid gelsemoxonine 3 was isolated. Erick M. Carreira of the Eidgenössische Technische Hochschule Zürich envisioned (J. Am. Chem. Soc. 2013, 135, 8500) that the unusual azetidine ring of 3 could be established by Brandi contraction of 1 to give 2. Following Brandi and Salaün (Eur. J. Org. Chem. 1999, 2725), the hemiketal 4 was carried onto the aldehyde 9. Condensation with nitromethane followed by dehydration gave the unsaturated nitrile oxide, which cyclized to 10. Epoxidation of 10 across the more open face gave an intermediate epoxide. Addition of 11 to the epoxide, promoted by InBr3, delivered 12 with good stereocontrol. CeCl3-mediated addition of 1-propynyl lithium completed the assembly of 1. A cyclopropanone could be seen as the addition product of carbon monoxide to an alkene. On exposure of 1 to acid, this formal addition was reversed, leading to the β-lactam 2. A computational study of this cleavage was recently reported (Eur. J. Org. Chem. 2011, 5608). Conceptually, one can imagine protonation activating the C–N bond for cleavage, leading to an intermediate such as 14, which then fragments to the acylium ion, leading to cyclization. It is unlikely that 14 would have any real lifetime. On warming with the Petasis reagent, the Boc-protected β-lactam was converted to the alkene 15. Hydroboration proceeded to give the alcohol 16 as a single diastereomer. Reduction followed by oxidation to 17 then set the stage for intramolecular aldol condensation to give 18. The last challenge was the diastereoselective assembly of the N-methoxyoxindole. To this end, oxidation and dehydration of 18 led to the bromo amide 20. As hoped, Heck reductive cyclization proceeded across the more open face of the alkene, leading to 21. Hydroxyl-directed hydrosilylation of the pendant alkyne to give the ethyl ketone then completed the synthesis of gelsemoxonine 3. Twice in this synthesis, advantage was taken of the preparation and reactivity of heteroatom-substituted alkenes. Dimethyl dioxirane, generated as a solution in acetone, was sufficiently water free that the epoxide derived from 10 could survive long enough to react in a bimolecular sense with the ketene silyl acetal 11.
Тези доповідей конференцій з теми "Β-reach":
1
Arhami, M., F. Sarioglu, and A. Kalkanli. "Effect of Heat-Treatment and Reinforcement With Silicon Carbide on the Microstructure and Mechanical Properties of AlFeVSi Alloy." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42073.
Анотація:
The aging response of Al-Fe-V-Si composite was compared with the un-reinforced alloy. The effects of solutionizing time, alloying element and SiC reinforcement on the age hardening response, microstructure and mechanical properties of these alloy and its composites was also investigated. The study was performed by T6 heat treatment at three different solutionizing times. Room temperature tensile testing was conducted for peak aged specimens to determine the effect of this heat treatment on the strength of squeezed cast un-reinforced and reinforced Al-Fe-V-Si alloy with SiC particles. The presence of SiC particles accelerated the aging kinetics of the composites compared to the unreinforced alloys. The time to reach peak age hardness was decreased by addition of SiCp. Mainly two different Fe-intermetallics; small α-Al7(Fe, V)3Si and large β-Al18Fe11Si phases were present in the system studied. The fracture surfaces of composites revealed decohesion of SiC particles from the matrix and cracking of needle like-β intermetallics was observed.
2
Godazandeh, K., M. H. Ansari, B. Godazandeh, and M. Ashjaee. "Optimization of the Angle of Attack of Delta-Winglet Vortex Generators Over a Bank of Elliptical-Tubes Heat Exchanger." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64179.
Анотація:
In order to reach a more efficient and compact heat exchanger, it is essential to optimize the design, having in mind the impact of different geometrical parameters. Many of the previously cited studies in the area of heat transfer enhancement using vortex generators were confined only to defined points in the possible design space. Thus, a multi-objective optimization study is particularly suitable in order to cover this space entirely. A CFD simulation along with Pareto method were used to simulate the air flow and heat transfer and optimize the design parameters. The angle of attack of a pair of delta-winglets mounted behind each tube is varied between β = −90° and β = +90°. Three elliptical tube rows with inline arrangements are investigated for Reynolds numbers from 500 to 1500 (based on the inlet properties). Use of delta-winglets as heat transfer enhancement elements increases the performance of elliptical-tubes heat exchanger. This enhancement is mainly due to the fact that delta-winglets increase the level of vorticity inside these devices and thus the mixing of the fluid is enhanced.
3
Mansour, James, Badih A. Jawad, Sabah Abro, Liping Liu, Vernon Fernandez, and Jeff Tibbenham. "Critical Factors That Impact Consistency of Fit and Finish at the Rear Fascia Cutline of Vehicles." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70341.
Анотація:
A vehicle’s exterior fit and finish, in general, is the first part to attract customers. For this reason, customers consider the J.D. Power report which classifies all vehicles based on different criteria. One of the criteria is the vehicle exterior fit and finish which is measured by two important factors called Flush and Gap. Automotive exterior engineers have been motivated in the past few years to increase their focus on optimizing the vehicle’s exterior panels split lines quality and minimizing variation in fit and finish to address customer and market quality standards. Design engineers focus on controlling the deviation from nominal build objective and minimizing it. This study focuses on addressing the contributed factors that impact the quality of fit and finish. These critical factors resulted from the design process, product process and from the assembly process. An empirical analysis was used to minimize the fit and finish deviation. Models that accurately describe the response values by experiments helped identify the most critical factors, and an analytical model and Response Surface Methodology (RSM) were used to optimize the acceptable values on these factors. Early results showed that some of these factors are critical for improving the quality of the fascia cutline fit and finish by obtaining more consistent gap and flush along the rear fascia cutline as well as reducing the offset issue. The results of this study identified 17 critical factors which were split between controls and can be dialed to change the magnitude of the results and noises which have less effect on changing the results. Also, the 17 factors were separated into factors that affect Gap “α” or factors that affect flush “β” or both. Eight factors were selected based on production experience and based on their levels. Empirical analysis was conducted to generate regression models for both α & β. The selected factors were tested for their effect; also, the study took in consideration of different combined effect of these factors. Optimization with these factors were conducted for α & β. The results show that α can approach ±0.5 mm and β can approach ± 1 mm. The conclusion is that the consistency of α & β along the fascia to bodyside panel cutline (defined as ϴ) will be maximum when both α & β are minimum. The ultimate goal is to reach the stretched target which means zero mm gap and zero mm flush.
4
Malley-Ernewein, Alexandre, and Sylvie Lorente. "Constructal Open Reactors for Thermochemical Energy Storage." In ASME 2019 Heat Transfer Summer Conference collocated with the ASME 2019 13th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ht2019-3455.
Анотація:
Abstract This work documents the study of two concepts of open reactors for thermochemical energy storage. While classical thermal storage uses sensible or latent heat to store thermal energy, thermochemical energy storage uses an endothermic / exothermic chemical reaction. The process studied is based on the hydration and dehydration of a reactive salt by a flow of moist air in order to release and store heat respectively. The first concept studied is a storage module composed by the pattern “one salt bed surrounded by an inlet and an outlet channel, placed in parallel”. The second concept is a storage module made of by tubes impregnated with the reactive salt on their intern face. In this configuration, the tubes and the impregnated salt layer length scales are in the order of micrometer. Both concepts are presented using the Constructal law of design. In the first concept, air flows through the salt bed, corresponding to a forced convection through porous media problem, whereas in the second concept the air flow licks the impregnated salt and the chemical reaction occurs within the salt thanks to diffusion only. The analytical part is based on the Constructal law approach. From the main trends in terms of pressures distribution the geometrical features are deduced to obtain the design of compact and thermally efficient systems. Next, the discovered trends are backed up with numerical experiments. The geometrical dimensions are morphed with the purpose to move towards better performances. A ratio β between the heat produced by the chemical reaction within the entire module and the overall pumping power necessary to blow the fluid is determined to compare the configurations of each concepts. In accord with Constructal design, the number of salt beds in the first concept is morphed to reach equipartition of imperfections. The results show that with this evolution, the ratio β increases. In the second concept, the salt volume must be allocated in such a way that the time for water vapor diffusion through the salt matches the time for hydration / dehydration.
5
Bu, H., B. Jodoin, M. Yandouzi, and C. Lu. "Investigation of Heat Treatment on Cold Sprayed Aluminum Coatings on Magnesium Substrates with Different Status." In ITSC2011, edited by B. R. Marple, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and A. McDonald. DVS Media GmbH, 2011. http://dx.doi.org/10.31399/asm.cp.itsc2011p0908.
Анотація:
Abstract Large pure aluminum powders were deposited on as cast-, T4- and T6-AZ91D magnesium substrates using cold spray. Heat treatment was applied to the coated components under vacuum at 400°C for different holding time. The effects of the heat treatment on the microstructure as well as the coating/substrate adhesion strength were investigated. Thick (~ 400µm) and dense (<1% porosity) Al coatings have been obtained on the three different substrates. During heat treatment, Mg17Al12 (β) and Al3Mg2 (γ) intermetallic phases were formed at the Al/Mg interface and the thickness of the intermetallics layers increased with the holding time. No significant thickness difference of the intermetallics layers were observed on as cast- and T6-AZ91D substrates, while thicker layers took place on the T4- substrate. It is believed that the higher Al concentration within the T4-AZ91D material could be beneficial for intermetallic growth because less enrichment is required to reach the critical level for intermetallic formation in the substrate. Shear strength tests were performed on the as sprayed and after heat treatment coatings. The results revealed lower adhesion strength in the samples after heat treatment than the as sprayed ones which is attributed to the presence of brittle intermetallics layers at the coating/substrate interface.
6
Ma, D. D., G. D. Xia, W. Wang, X. F. Li, and Y. T. Jia. "Channel Size Optimization for 3D-IC Integrated Interlayer Microchannel Liquid Cooling." In ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/mnhmt2016-6478.
Анотація:
3D-IC is getting increasingly attractive, as it improves speed and frequency, and reduces power consumption, noise and latency. However, three dimension (3D) integration technologies bring a new serious challenge to chip thermal management with the power density increased exponentially. Interlayer microchannel liquid cooling is thought as a promising and scalable solution for cooling high heat flux 3D-IC. In this paper, firstly channel number, channel width and height parameters of rectangular channel are optimized by the method of multi-objective parameter optimization under given overall size of 5mm in length and 5mm in width. The results show the total thermal resistances can reach very small under individual constraint condition of volume flow rates, but the pressure drop is too larger to accept. The minimum thermal resistance structure can be got by multi-objective optimization at various constraint conditions. It is found that the channel height and width increase with increasing of flow rates at pumping power less than 0.1W and pressure drop less than 20kPa. Secondly, the zigzag channels are designed on the basis of the optimized rectangular channel structure. The expansion and contraction ratio as an important parameter is optimized by numerical simulation. The thermal enhancement factor and Nusselt number measure the comprehensive performances of heat transfer. The results show heat transfer characteristic is enhanced with the decreasing of expansion and contraction ratio. Besides, the maximum junction temperature and maximum temperature difference are also reduced. 3D-IC with wave channel of β=3/7 is more promising for interlayer cooling.
7
Coda, Alberto, Carlo Alberto Biffi, Jannis Nicolas Lemke, Jacopo Fiocchi, and Ausonio Tuissi. "Laser Straight Annealing of HT-SMA Thin Wires." In SMST 2024. ASM International, 2024. http://dx.doi.org/10.31399/asm.cp.smst2024p0123.
Анотація:
Abstract In recent years, the interest in shape memory alloys with high transformation temperatures (HTSMA) has significantly increased not only in the academic sphere, but also due to a market-push, especially from aerospace, automotive, and robotics. However, a real break-through has not been achieved yet because of several problems: Lower chemistry control than in NiTi alloys, instability of martensite, decomposition of the matrix phase, brittleness, oxidation, etc. Despite those challenges, steady progress has been made on specific systems and distinct thermo-mechanical treatments have been elaborated to reach promising HT-SMA behavior. Among several systems, Ni-Ti-Hf-Nb emerged as particular promising due to superior mechanical properties of its alloys compared to those of the ternary Ni-Ti-Hf system. In particular, the ductility of Ni-Ti-Hf increases significantly by adding Nb, allowing for formation of a soft eutectic network composed of shape memory matrix phase and a not transforming β-Nb phase at the grain boundaries. Recently, it was demonstrated that by this alloying approach, it is possible to obtain fine wires using conventional drawing techniques, increasing the opportunities for a successful industrial commercialization. In this work, Laser technology was explored for straight annealing of HT-SMA wires and promoting shape memory behavior. The functional performances of laser treated wires were assessed through differential scanning calorimetry (DSC), microstructure analysis, tensile tests and thermal cycling under constant load. Laser parameters were optimized for tailoring transformation properties in order to get a stable transformation at high temperatures, the results were compared to those ones of furnace annealed wires.
8
Hourcade, E. "Physics of Plutonium and Americium Recycling in PWR Using Advanced Fuel Concepts." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49604.
Анотація:
PWR waste inventory management is considered in many countries including Frances as one of the main current issues. On this subject, the French 1991 Bataille’s law set up a 15 years research program on three main axes: sub-surface storage, deep geological storage, transmutation using critical or subcritical burners. Amongst the output Actinides, Pu and Am are the 2 main contents both in term of volume and long term radio-toxicity. Waiting for the Generation IV systems implementation (2035–2050), one of the mid-term solutions for their transmutation involves the use of advanced fuels in Pressurized Water Reactors (PWR). These have to require as little modification as possible of the core internals, the cooling system and fuel cycle facilities (fabrication and reprocessing). The present paper is focussed on the reactor physics characteristics, as a preliminary step in the evaluation of options, knowing that others homogeneous and heterogeneous assemblies have been studied by the CEA ([1] to [5]). The main neutronic parameters to be considered for Pu and Am recycling in PWR are void coefficient (αvoid), Doppler coefficient (αDopp), fraction of delayed neutrons (β) and power distribution (especially for heterogeneous configurations). The modification of the moderation ratio, the opportunity to use inert matrices (targets), the optimisation of Uranium, Plutonium and Americium contents are the key parameters to play with. One of the solutions presented here is a heterogeneous assembly with regular moderation ratio composed with both target fuel rods (Pu and Am embedded in an inert matrix) and standard UO2 fuel rods. An EPR (European Pressurised Reactor) type reactor, loaded only with assemblies containing 84 peripheral targets, can reach an Americium consumption rate of [4.4; 23 kg/TWhe] depending on the assembly concept. For Pu and Am inventories stabilisation, the theoretical fraction of reactors loaded with Pu + Am or Pu assemblies is about 60%. For Americium inventory stabilisation, the fraction decreases down to 16%, but Pu is produced at a rate of 18.5 Kg/Twhe (−25% compared to one through UOX cycle).
9
"Effect of Food-Based Nutrition Education Intervention on Nutrition Knowledge, Attitudes, Practices and Food-use Among School-age Children in Homa-Bay, Kenya." In 3rd International Nutrition and Dietetics Scientific Conference. KENYA NUTRITIONISTS AND DIETICIANS INSTITUTE, 2023. http://dx.doi.org/10.57039/jnd-conf-abt-2023-m.i.y.c.n.h.p-27.
Анотація:
Micronutrient malnutrition (hidden hunger) is still a major problem in Kenya and other developing countries, particularly among school-age children who are rarely targeted by nutrition interventions. Studies indicate that food-based nutrition education (FBNE) interventions are effective in improving the adoption of recommended nutrition practices among school-age children. However, there is little evidence of the effectiveness of such interventions in developing countries such as Kenya. This study aimed to assess the effects of a FBNE intervention on nutrition Knowledge, Attitudes and Practices (KAP) and food use among grade six children in Ndhiwa Sub-County, Homa-Bay County, Kenya. A pre-post quasi-experimental design with intervention and control groups was used and was conducted from January to March 2021. The intervention was implemented using a FBNE curriculum developed using the health belief model constructs and was piloted with grade six Kenyan school children in 2 schools in Ndhiwa, Kenya. Participants in both the intervention and comparison groups were highly knowledgeable on handwashing prior to the intervention which was attributed to hygiene campaigns during COVID-19; and this remained similar postintervention p=0.22 and p=0.13, respectively. After the intervention, the intervention group had higher positive attitudes regarding handwashing (p=0.01) and practiced more handwashing (p=0.03) than the comparison group. Knowledge scores (p=0.0001), attitudes scores (p=0.0001), barriers scores (p=0.002) and practices scores (p=0.002) related to iron and zinc were significantly higher in the intervention than in the comparison group. Similarly, knowledge scores (p=0.004), attitudes scores (p=0.002) and practices scores (p=0.0001) related to Vitamin C and β carotene were also higher in the intervention group than in the comparison group. In addition, kitchen gardening knowledge (p=0.01) and attitudes (p=0.01) increased significantly in the intervention group relative to the comparison group. Food-based nutrition intervention is effective on nutrition KAP of the school children and more opportunities within and outside the formal curriculum should be explored to reach the children with more context-based information for positive behaviour change to end micronutrient deficiencies among adolescents. Longitudinal studies to investigate the long-term effects of this food-based intervention on nutrition KAP, and dietary behaviour change and associations with micronutrient status. Key words: Food-based Nutrition Education, Knowledge, Attitudes and Practices (KAP), School-age Children, Kenya.
10
Nishino, N., Y. Tokura, S. Sakaguchi, S. Takahashi, Y. Takada, and A. Takada. "URINARY TRYPSIN INHIBITOR RELATED SUBSTANCE (UTIR) IN THE PLASMA AND TISSUES OF STOMACH CANCER." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643193.
Анотація:
Urinary trypsin inhibitor(UTI) is a single chain glycoprotein with molecular weight of 67,000. In SDS-PAGE a hand appeared at molecular weight of 48,000. Results of gel filtration indicate its molecular weight of 67,000, suggesting extensive changes in its conformation in SDS. Injection of UTI into rabbit did not result in the formation of anti-UTI antibody. Conjugation of rabbit serum albumin with UTI gave rise to antibody formation upon injection into rabbits. Anti-UTI did not cross-react with anti-inter(Xtrypsin inhibitor. A highly sensitive enzyme immunoassay of UTI was developed using β-D-galactosidase coupled to Fab' of anti-UTI. The inhibition of the hydrolysis of TAMe by trypsin was used for the functional assay of UTI. Functional assay of UTI showed a good correlation of UTI antigen (UTIR) to the UTI activity in the urine. UTIR levels in the plasma of the normal male volunteers were 198.0 ± 15.7 μg/ml, and did not change with increasing age. Cancer tissue of patients with stomach cancer showed higher UTIR than surrounding healthy tissue, and urine of such patients had higher UTI.In conclusion, UTIR were present in the plasma and tissue of normal persons, and UTI levels in the urine of cancer patients increased, and cancer tissues of patients with stomach cancer seem to have higher UTIR than that in sorrounding normal tissues.
Звіти організацій з теми "Β-reach":
1
Schwartz, Bertha, Vaclav Vetvicka, Ofer Danai, and Yitzhak Hadar. Increasing the value of mushrooms as functional foods: induction of alpha and beta glucan content via novel cultivation methods. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600033.bard.
Анотація:
During the granting period, we performed the following projects: Firstly, we differentially measured glucan content in several pleurotus mushroom strains. Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. In our first study, we explored several Pleurotus species for their total, β and α-glucan content. Pleurotuseryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotuseryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate. We then compared the immune-modulating activity of glucans extracted from P. ostreatus and P. eryngii on phagocytosis of peripheral blood neutrophils, and superoxide release from HL-60 cells. The results suggest that the anti-inflammatory properties of these glucans are partially mediated through modulation of neutrophileffector functions (P. eryngiiwas more effective). Additionally, both glucans dose-dependently competed for the anti-Dectin-1 and anti-CR3 antibody binding. We then tested the putative anti-inflammatory effects of the extracted glucans in inflammatory bowel disease (IBD) using the dextran sulfate sodium (DSS)–induced model in mice. The clinical symptoms of IBD were efficiently relieved by the treatment with two different doses of the glucan from both fungi. Glucan fractions, from either P. ostreatus or P. eryngii, markedly prevented TNF-α mediated inflammation in the DSS–induced inflamed intestine. These results suggest that there are variations in glucan preparations from different fungi in their anti-inflammatory ability. In our next study, we tested the effect of glucans on lipopolysaccharide (LPS)-induced production of TNF-α. We demonstrated that glucan extracts are more effective than mill mushroom preparations. Additionally, the effectiveness of stalk-derived glucans were slightly more pronounced than of caps. Cap and stalk glucans from mill or isolated glucan competed dose-dependently with anti-Dectin-and anti-CR-3 antibodies, indicating that they contain β-glucans recognized by these receptors. Using the dextran sulfate sodium (DSS)-inflammatory bowel disease mice model, intestinal inflammatory response to the mill preparations was measured and compared to extracted glucan fractions from caps and stalks. We found that mill and glucan extracts were very effective in downregulatingIFN-γ and MIP-2 levels and that stalk-derived preparations were more effective than from caps. The tested glucans were equally effective in regulating the number of CD14/CD16 monocytes and upregulating the levels of fecal-released IgA to almost normal levels. In conclusion, the most effective glucans in ameliorating some IBD-inflammatory associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii. These spatial distinctions may be helpful in selecting more effective specific anti-inflammatory mushrooms-derived glucans. We additionally tested the effect of glucans on lipopolysaccharide-induced production of TNF-α, which demonstrated stalk-derived glucans were more effective than of caps-derived glucans. Isolated glucans competed with anti-Dectin-1 and anti-CR3 antibodies, indicating that they contain β-glucans recognized by these receptors. In conclusion, the most effective glucans in ameliorating IBD-associated symptoms induced by DSS treatment in mice were glucan extracts prepared from the stalk of P. eryngii grown at higher concentrations of OMSW. We conclude that these stress-induced growing conditions may be helpful in selecting more effective glucans derived from edible mushrooms. Based on the findings that we could enhance glucan content in Pleurotuseryngii following cultivation of the mushrooms on a substrate containing different concentrations of olive mill solid waste (OMSW) and that these changes are directly related to the content of OMSW in the growing substrate we tested the extracted glucans in several models. Using dextran sulfate sodium (DSS)–inflammatory bowel disease (IBD) mice model, we measured the colonic inflammatory response to the different glucan preparations. We found that the histology damaging score (HDS) resulting from DSS treatment reach a value of 11.8 ± 2.3 were efficiently downregulated by treatment with the fungal extracted glucans, glucans extracted from stalks cultivated at 20% OMSWdownregulated to a HDS value of 6.4 ± 0.5 and at 80% OMSW showed the strongest effects (5.5 ± 0.6). Similar downregulatory effects were obtained for expression of various intestinal cytokines. All tested glucans were equally effective in regulating the number of CD14/CD16 monocytes from 18.2 ± 2.7 % for DSS to 6.4 ± 2.0 for DSS +glucans extracted from stalks cultivated at 50% OMSW. We finally tested glucans extracted from Pleurotuseryngii grown on a substrate containing increasing concentrations of olive mill solid waste (OMSW) contain greater glucan concentrations as a function of OMSW content. Treatment of rat Intestinal epithelial cells (IEC-6) transiently transfected with Nf-κB fused to luciferase demonstrated that glucans extracted from P. eryngii stalks grown on 80% OMSWdownregulatedTNF-α activation. Glucans from mushrooms grown on 80% OMSW exerted the most significant reducing activity of nitric oxide production in lipopolysaccharide (LPS) treated J774A.1 murine macrophages. The isolated glucans were tested in vivo using the Dextran Sodium Sulfate (DSS) induced colitis in C57Bl/6 mice and found to reduce the histology damaging score resulting from DSS treatment. Expression of various intestinal cytokines were efficiently downregulated by treatment with the fungal extracted glucans. We conclude that the stress-induced growing conditions exerted by OMSW induces production of more effective anti-inflammatory glucans in P. eryngii stalks.
2
Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock, and Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
Анотація:
Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.