bluuebunny/crossref_metadata_2025 huggingface dataset:
A National Survey of Prosthesis Use in Veterans with Major Upper Limb Amputation: Comparisons by Gender
Authors: Resnik Linda J. , Borgia Matthew L. , Clark Melissa A.
Published: February 2020

Background

A better understanding of women veterans with upper limb amputation is needed.

Objective

To compare prosthetic use and outcomes of female and male veterans with upper limb amputation.

Design

Cross‐sectional survey: Amputation characteristics, prosthesis use, and quality of life outcomes were compared by gender. Separate logistic regression models examined association of gender with prosthesis use and receipt of training to use a prosthesis. Separate linear regression models examined the relationship between gender and health‐related quality of life (HRQoL) outcomes.

Participants

Participants were veterans with major upper limb amputation who received care at the Department of Veterans Affairs (VA) in 2010‐2015, identified from VA data sources. A total of 808 individuals (755 men, 21 women) were surveyed by telephone.

Main Outcome Measures

Disabilities of the Arm, Shoulder and Hand (QuickDASH), VR‐12 Physical Component Summary (PCS) and VR‐12 Mental Component Summary (MCS), Trinity Amputation and Prosthetic Experience Scale satisfaction scale, Orthotics and Prosthetic User's Survey client satisfaction with devices scale.

Setting

Telephone survey of community dwelling participants.

Interventions

Not applicable.

Results

Survey response rate was 47.3% for men and 62.8% for women. Women were less likely to have ever used a prosthesis (adjusted odds ratio [aOR] = 0.26; confidence interval [CI] 0.08‐0.88), have received training for an initial prosthesis (aOR: 0.24; CI 0.08‐0.70), be current users (aOR = 0.34; CI 0.12‐1.01), and have received training for a current prosthesis (aOR: 0.15; 0.03‐0.87). A greater proportion of women used cosmetic and a smaller proportion used body‐powered devices compared to men (P < .05). Device heaviness or fatigue was the most common reason for abandonment. There were no significant differences in outcome measures by gender.

Conclusions

Women were less likely than men to have ever used and currently use prostheses or to have received prosthetic training, more likely to use cosmetic devices, and less likely to use body‐powered devices. Efforts to develop prostheses that are cosmetically acceptable, yet lightweight and functional, are needed.
Construction method and application of real‐time monitoring and early‐warning model for anaerobic reactor leakage
Authors: Wang Feng , Deng Fujie , Wang Yipeng
Published: February 2020

The anaerobic reactor is one of the most critical reaction devices for biogas engineering, wherein is usually a large amount of flammable gas methane. Fire and explosion accidents will be easily triggered if the gas leaks, threatening the surrounding buildings, equipment, personnel, and so forth. Avoiding the significant accidents caused by CH4 leakage has become a critical issue in the design and condition monitoring for an anaerobic reactor. This article presents a model construction method for leakage early‐warning. Incident database and hazard and operability analysis (HAZOP) can be utilized to identify the leakage risks, and computational fluid dynamics (CFD) simulation and consequence quantity calculation can be used to determine the consequence influence ranges. The calculation results can be employed to establish prediction models for abnormal situations. Process safety management (PSM) data and risk analysis results can be combined with the possible abnormal situations to assist operators in adopting the right solutions. An early‐warning system has been developed to illustrate the industrial application of the model. It can be concluded that collecting multi‐parameter values according to the real‐time changes in the actual production process, continuous monitoring and early‐warning of leakage risk, and so forth, will contribute to accident avoiding and emergency response in reactor operations.
X‐Ray Diffraction Microstrain Analysis for Extraction of Threading Dislocation Density of GaN Films Grown on Silicon, Sapphire, and SiC Substrates
Authors: Yon Victor , Rochat Névine , Charles Matthew , Nolot Emmanuel , Gergaud Patrice
Published: February 2020

X‐Ray diffraction microstrain characterization is a technique which enables the quantification of threading dislocations by measuring the radial microstrain field surrounding these defects. This work demonstrates how to accurately perform these measurements on a broad range of GaN samples. In particular, for GaN grown on Si substrates with large stress gradient through the layer, the measurements need to be performed on the (20–25) reflection to avoid being affected by a macrostrain influence. A comparison of this characterization with cathodoluminescence and X‐ray diffraction lattice misorientations measurements shows differences in the measurement depth, so the results are affected by the various evolutions of dislocations densities through the layers of the different samples. Independently of the measurement depth, the analysis also highlights a dependence of the X‐ray measurements results on the type of sample, in particular the starting substrate. Microstrain measurements appear therefore as being well suited for the comparison of threading dislocations densities between similar GaN layers. It can be used to replace lattice misorientations measurements, or be associated with them to obtain an edge versus screw dislocations ratio.
Effectiveness of an encecalin standardized extract of Ageratina pichinchensis on the treatment of onychomycosis in patients with diabetes mellitus
Authors: Romero‐Cerecero Ofelia , Islas‐Garduño Ana Laura , Zamilpa Alejandro , Tortoriello Jaime
Published: February 2020

Ageratina pichinchensis is utilized in traditional medicine for the treatment of dermatomycosis and inflammation. The aim of this study was to evaluate the clinical and mycological effectiveness of the topical administration of an enecalin standardized extract of A. pichinchensis for treating onychomycosis in patients with type 2 diabetes mellitus (DM2). A double blind, randomized, and controlled clinical trial was carried out that included patients with DM2 and who had mild or moderate onychomycosis. Participants were administered topically, for 6 months, a lacquer containing the encecalin standardized extract of A. pichinchensis (experimental group) or 8% ciclopirox (control group). In a large percentage of both, the control group (77.2%) and the experimental group (78.5%), clinical efficacy was detected as a decrease in the number of affected nails and a reduction in the severity of nail involvement. Without exhibiting statistically significant differences between groups, the encecalin standardized extract of A. pichinchensis was clinically and mycologically effective in the treatment of mild and moderate onychomycosis in patients with DM2. The treatment of onychomycosis in patients with DM2 implies a greater challenge, while control of blood glucose levels in these patients, played a very important role in the response of patients to treatment.
Investigation of rosemary herbal extracts (Rosmarinus officinalis) and their potential effects on immunity
Authors: Ahmed Hiwa M. , Babakir‐Mina Muhammed
Published: February 2020

The discovery of new curative drugs and the consumption of natural dietary ingredients with the ability to exhibit immunomodulatory activity is urgently needed to decrease the risk of chronic diseases among the population. Rosmarinus officinalis (Lamiaceae) is an aromatic plant that has been traditionally and medicinally used as a carminative, antispasmodic, painkiller, circulatory tonic, to stimulate hair growth and to improve memory dysfunction. This study aimed to assess the potential effects of rosemary solvent extracts on human immune function. Science Direct, Web of Science, Wiley, Elsevier, PubMed, Scopus, and the Google scholar search engines were used to retrieve relevant information included combinations of “rosemary” or “R. officinalis” with “immune function,” “immunity,” “immune system,” “anti‐inflammatory,” “inflammation,” or “health benefit.” A number of studies have been found a stimulatory effect of rosemary and its active compounds on the immune system in vitro and animal study, but there is a lack of evidence in humans for supporting this. The results demonstrated the potential of rosemary and its main active components as dietary ingredients with immunomodulatory functionality. Human studies should be performed and a double‐blind randomized controlled trial would be ideal.
Asymptotic tracking control for constrained nonstrict‐feedback MIMO nonlinear systems via parameter compensations
Authors: Du Peihao , Pan Yingnan , Chadli Mohammed , Zhao Shiyi
Published: February 2020

This paper studies the problem of adaptive fuzzy asymptotic tracking control for multiple input multiple output nonlinear systems in nonstrict‐feedback form. Full state constraints, input quantization, and unknown control direction are simultaneously considered in the systems. By using the fuzzy logic systems, the unknown nonlinear functions are identified. A modified partition of variables is introduced to handle the difficulty caused by nonstrict‐feedback structure. In each step of the backstepping design, the symmetric barrier Lyapunov functions are designed to avoid the breach of the state constraints, and the issues of overparametrization and unknown control direction are settled via introducing two compensation functions and the property of Nussbaum function, respectively. Furthermore, an adaptive fuzzy asymptotic tracking control strategy is raised. Based on Lyapunov stability analysis, the developed control strategy can effectually ensure that all the system variables are bounded, and the tracking errors asymptotically converge to zero. Eventually, simulation results are supplied to verify the feasibility of the proposed scheme.
Returning to Text: Affect, Meaning Making, and Literacies
Authors: Burnett Cathy , Merchant Guy
Published: February 2020

Existing work on literacy and affect has posed important questions for how we think about meanings and how and where they get made. The authors contribute to such work by focusing on the relation between text and affect. This is a topic that has received insufficient attention in recent work but is of pressing concern for education as text interweaves in new ways with human activity, through social media, surveillance capitalism, and artificial intelligence—ways that can be unpredictable and poorly understood. Adopting a sociomaterial sensibility that foregrounds the relations between bodies (people and things), the authors provide conceptual tools for considering how texts affect and are affected by the heterogeneous entanglements from which they emerge. In situating their argument, the authors outline influential readings of Spinoza’s theories of affect, explore how these have been mobilized in literacy research, and identify how text has been accommodated within such research. Using texts from a political episode in the United Kingdom, the authors explore the idea of social‐material‐textual affects to articulate relations among humans, nonhumans, meaning making, and literacies. The authors conclude by identifying four ways in which text participates in what happens, raising questions about how different materializations of text (or indeed “not text”) are significant to the diversifying communicative practices that inflect social, cultural, economic, and political life.
Propensity scores using missingness pattern information: a practical guide
Authors: Blake Helen A. , Leyrat Clémence , Mansfield Kathryn E. , Seaman Shaun , Tomlinson Laurie A. , Carpenter James , Williamson Elizabeth J.
Published: February 2020

Electronic health records are a valuable data source for investigating health‐related questions, and propensity score analysis has become an increasingly popular approach to address confounding bias in such investigations. However, because electronic health records are typically routinely recorded as part of standard clinical care, there are often missing values, particularly for potential confounders. In our motivating study—using electronic health records to investigate the effect of renin‐angiotensin system blockers on the risk of acute kidney injury—two key confounders, ethnicity and chronic kidney disease stage, have 59% and 53% missing data, respectively. The missingness pattern approach (MPA), a variant of the missing indicator approach, has been proposed as a method for handling partially observed confounders in propensity score analysis. In the MPA, propensity scores are estimated separately for each missingness pattern present in the data. Although the assumptions underlying the validity of the MPA are stated in the literature, it can be difficult in practice to assess their plausibility. In this article, we explore the MPA's underlying assumptions by using causal diagrams to assess their plausibility in a range of simple scenarios, drawing general conclusions about situations in which they are likely to be violated. We present a framework providing practical guidance for assessing whether the MPA's assumptions are plausible in a particular setting and thus deciding when the MPA is appropriate. We apply our framework to our motivating study, showing that the MPA's underlying assumptions appear reasonable, and we demonstrate the application of MPA to this study.
Modified models and simulations for estimating dynamic functional connectivity in resting state functional magnetic resonance imaging
Authors: Behboudi Maryam , Farnoosh Rahman
Published: February 2020

As understanding the nature of brain networks through dynamic functional connectivity (dFC) estimation is of paramount significant, the introduction and revision of blood‐oxygen‐level dependent (BOLD) signal simulation methods in brain regions and dFC estimation methods have gained significant ground in recent years. Based on the observation of BOLD signals with multivariate nonnormal distribution in functional magnetic resonance imaging (fMRI) images, we first propose a copula‐based method for the production of these signals, in which nonnormal data are generated with a selected time‐varying covariance matrix. Therefore, we can compare the performance of models in the cases where brain signals have a multivariate nonnormal distribution. Then, two kendallized exponentially weighted moving average (KEWMA) and kendallized dynamic conditional correlation (KDCC) multivariate volatility models are introduced which are based on two well‐known and commonly used exponentially weighted moving average (EMWA) and dynamic conditional correlation (DCC) models. The results show that KDCC model can estimate conditional correlation significantly far better than the former ones (ie, DCC, standardized dynamic conditional correlation, EWMA, and standardized exponentially weighted moving average) on both types of data (ie, multivariate normal and nonnormal). In the next step, the bivariate normal distribution in Iranian resting state fMRI data is confirmed by using statistical tests, and it is shown that the dynamic nature of FC is not optimally detected using prevalent methods. Two alternative Portmanteau and rank‐based tests are proposed for the examination of conditional heteroscedasticity in data. Finally, dFC in these data is estimated by employing the KDCC model.
When one door closes, another door opens … for some: Evidence from the post‐TRIPS Indian pharmaceutical industry
Authors: Chattopadhyay Shinjinee , Bercovitz Janet
Published: February 2020

Research Summary

Firms' strategy choices are contextually dependent, yet internally delimited. A radical shift in institutional context forces firms to reevaluate the desirability and suitability of current strategies and assess the potential of new strategic opportunities. From 1970 to 1995, the Indian pharmaceutical industry operated under a process‐focused intellectual property regime and enjoyed legal protection to reverse engineer brand name drugs. In 1995, this protection ended with the introduction of the trade‐related aspects of intellectual property rights (TRIPS) Act. We examine the innovation response of Indian pharmaceutical firms in light of this regime shift focusing on the underlying internal factors influencing firms' strategic choices. We find that the scope and balance of firms' knowledge bases, which set capabilities and influence decision framing, dictate firms' innovative response. We further document how firms' strategic choices contribute to firm financial performance and the reshaping of the Indian pharmaceutical industry.

Managerial Summary

From 1970 to 1995, the Indian pharmaceutical industry operated under a process‐focused intellectual property regime and enjoyed legal protection to reverse engineer brand name drugs. Following TRIPS in 1995, the intellectual property regime in India became stronger, with product patent enforcement being recognized. Indian pharmaceutical firms had to make strategic choices on the kind of innovation they would pursue under this new IP regime. This article shows that having broad and nonspecialized knowledge assets allowed firms to pursue the most novel innovation and engage in new product development. Having T‐shaped assets, that is, broad knowledge scope yet narrowly focused knowledge expertise, allowed firms to pursue process‐based innovation in areas close to their existing areas of expertise but not necessarily engage in new product development. The findings of this article shed light on what kind of knowledge base and workforce allows firms to adjust to technological and contextual changes.
Enhanced Peltier Effect in Wrinkled Graphene Constriction by Nano‐Bubble Engineering
Authors: Hu Xudong , Gong Xue , Zhang Miao , Lu Huihui , Xue Zhongying , Mei Yongfeng , Chu Paul K. , An Zhenghua , Di Zengfeng
Published: February 2020

Inspired by the promising applications in thermopower generation from waste heat and active on‐chip cooling, the thermoelectric and electrothermal properties of graphene have been extensively pursued by seeking ingeniously designed structures with thermoelectric conversion capability. The graphene wrinkle is a ubiquitous structure formed inevitably during the synthesis of large‐scale graphene films but the corresponding properties for thermoelectric and electrothermal applications are rarely investigated. Here, the electrothermal Peltier effect from the graphene wrinkle fabricated on a germanium substrate is reported. Peltier cooling and heating across the wrinkle are visualized unambiguously with polarities consistent with p‐type doping and in accordance with the wrinkle spatial distribution. By direct patterning of the nano‐bubble structure, the current density across the wrinkle can be boosted by current crowding to enhance the Peltier effect. The observed Peltier effect can be attributed to the nonequilibrium charge transport by interlayer tunneling across the van der Waals barrier of the graphene wrinkle. The graphene wrinkle in combination with nano‐bubble engineering constitutes an innovative and agile platform to design graphene and other more general two‐dimensional (2D) thermoelectrics and opens the possibility for realizing active on‐chip cooling for 2D nanoelectronics with van der Waals junctions.
Ferrocene and titanocene steroid conjugates: Structures and activities – a brief review
Authors: Dembitsky Valery M. , Gloriozova Tatyana A. , Imbs Andrew B.
Published: February 2020

The present review describes the biological activities of ferrocenes and titanocenes steroid conjugates. Ferrocenes steroid conjugates demonstrate antineoplastic and antihypercholesterolemic activity with a confidence more than 90 percent, and can be used as erythropoiesis‐stimulating agents. Titanocenes steroid conjugates show anti‐inflammatory and anti‐seborrheic activity with a confidence more than 70 percent, and can also be used as glutaconyl‐CoA decarboxylase inhibitors and/or erythropoiesis‐stimulating agents. With the computer programme PASS and based on structure–activity relationships (SAR), some additional activities are also predicted, which point towards new possible applications of these lipids. This review is devoted to synthetic lipids ferrocenes and titanocenes steroid conjugates and their biological activity, which are of great interest for medicine, as well as for pharmacologists and the pharmaceutical industry.
Synthesis of novel artemisinin–triazole hybrids
Authors: Giang Le Nhat Thuy , Anh Dang Thi Tuyet , Phuong Hoang Thi , Thanh Nguyen Ha , Van Tuyen Nguyen
Published: February 2020

Several substituted triazole–artemisinin hybrids were synthesized based on ‘click’ chemistry between propargyl‐substituted derivatives and artemisinin containing a 2‐hydroxypropane unit. The structures of all obtained compounds were confirmed by means of IR, NMR, and MS spectroscopy. Four new hybrids were evaluated as cytotoxic agents, revealing an interesting anticancer activity of 1‐(4‐(3‐Aminophenyl)‐1H‐1,2,3‐triazol‐1‐yl)‐3‐(((3R,6R,8aS,9R,10S,12R,12aR)‐3,6,9‐trimethyl‐decahydro‐12H‐3,12‐epoxy[1,2]dioxepino[4,3‐i]isochromen‐10‐yl)oxy)propan‐2‐ol compound in KB and HepG2 cancer cell lines.
Bismuth nanodendrites deposited on glassy carbon electrode as a sensitive electrochemical sensor for simultaneous detection of Cd2+ and Pd2+ ions
Authors: Anh Nguyen Hoang , Duy Pham Khac , Yen Pham Thi Hai , Dang Vu Hai , Giao Nguyen Quynh , Ha Vu Thi Thu
Published: February 2020

In this study, bismuth nanodendrites (BiNDs) were fabricated on glassy carbon electrode by chronopotentiometric method. The hierarchical structure and high population matrix of BiNDs provides high surface active area to enhance the electrochemical signals of measured Cd2+ and Pb2+ ions. The developed bismuth nanodendritic structure was well‐observed and characterzied by scanning electron microscopy (SEM). Electrochemical behaviours of developed BiNDs electrodes were studied by the cyclic voltammetric (CV) method. The fabrication conditions for BiNDs such as the applied current and deposition time were optimized as ‐10 mA and 90 s, respectively. Under this optimized condition, the highest peaks of Cd2+ and Pb2+ ions at concentration of 20 ppb were obtained. The Cd2+ and Pb2+ signals acquired by BiNDs are almost three times greater than that measured by the Bi film electrode.
Synthesis of tantalum oxynitride with enhanced visible light efficiency in photoreduction of carbon dioxide
Authors: Le Chi Nguyen Thi Phuong , Tung Mai Hung Thanh , Van Hoang Cao , Cam Nguyen Thi Dieu , Thu Nguyen Thi Minh , Phuong Tran Thi Thu , Phuong Nguyen Minh , Van Noi Nguyen
Published: February 2020

The tantalum oxynitride (TaON) content in preparation process was increased with the melamine and tantalum pentoxide (Ta2O5) mass ratios. The Ta2O5 nitridation by melamine (C3H6N6) was occured in at 850 °C for 4 hours with various melamine and tantalum pentoxide mass ratios under a nitrogen gas flow. The photocatalytic performance of prepared samples was evaluated by the photoreduction of carbon dioxide into renewable fuel under visible light irradiation. Results show that the obtained photocatalysts exhibited a significant enhanced photocatalytic activity in comparison with pure Ta2O5. This work may be useful for a facile way to synthesize the highly efficient photocatalyst for application in energy conversion.
Chemical constituents of MeOH extract from the fruits of Macaranga sampsonii
Authors: Quynh Do Thi , Vu Le Tran Nguyen , Huong Doan Thi Mai , Ngan Truong Bich , Hue Nguyen Thi , Thach Tran Dang , Van Cuong Pham
Published: February 2020

The genus Macaranga belongs to the family Euphorbiaceaeconsistingof about 300 species that are mainly distributed inthe tropics of Africa, Asia, Australia, and the Pacific regions. Thirteen different species of this genus occur in Viet Nam, and Macaranga sampsonii has been used in traditional medicine to treat swellings, cuts, sores. Phytochemical investigation of the methanol extract of Macaranga sampsonii led to the isolation of six compounds including: boehmenan X (1), maltol β‐D‐glucopyranoside (2), methyl brevifolincarboxylate (3), scopoletin (4), 3,5‐dihydroxy‐4‐methoxy benzoic acid (5) and gallic acid (6). Their structures were confirmed by spectroscopic methods including IR, MS, 1D, 2D NMR and compared to previous reported spectral data values.
Study of water disinfection by analyzing the ozone decomposition process
Authors: Nghi Nguyen Hoang , Cuong Le Cao , Dieu Tran Vinh , Oanh Doan Thi Yen
Published: February 2020

Possessing high binding energy, molecular ozone (O3) is not stable and spontaneously breaks down into oxygen especially at high temperature. It is called thermal decomposition of ozone. On other hand, ozone with high redox potential (2.06 V) is considered to be a powerful oxidant. In water ozone reacts with both of inorganic and organic substances. Interaction of ozone with the matters consumes an amount of ozone dissolved in water. So by analysing the ozone decomposition curves, we can measure and calculate the reaction rate R, rate constant k, the half‐life time and reaction order of the ozone reaction with the matters. These parameters indicate the disinfection ability of ozone and its mechanism. Calculated value of half‐life time can be used to estimate the water quality and the water disinfection level.
Facile synthesis of urchin‐like gold nanoparticles using binary reducing agent composed of EDTA and hydroquinone
Authors: Nhat Hang Nguyen Thi , Phuong Phong Nguyen Thi
Published: February 2020

Urchin‐like gold nanoparticles (U‐AuNPs) were successfully synthesized through a rapid one‐pot seedless growth process. This method was carried out by using the combination of ethylenediaminetetraacetic acid (EDTA) and hydroquinone (HQ) as reducing agents. The effect of order of agents addition to the particle size was investigated. The obtained urchin‐like gold nanoparticles (NPs) were characterized by XRD, TEM and UV‐Vis absorption spectroscopy techniques. From the TEM analysis, it was found with different sizes of urchin‐like gold nanoparticles from 55 to 102 nm.
The synthesis and characterization of high purity mixed microporous/mesoporous activated carbon from rice husk
Authors: Tung Mai Thanh , Luong Vu Duc , Trang Pham Minh , Van Tuyen Le , Bich Thuy Hoang Thi , Wu Nae‐Lih
Published: February 2020

Rice husk (RH) is one of the most earth abundant, low‐cost, and ecofriendly agricultural residues. In this study, we successfully synthesized activated carbon from rice husk (RHAC) through carbonizing the rice husk and activating chemical by K2CO3. The effect of carbonization and activation temperature was investigated. At temperature of 800°C, activated carbon was obtained with high surface area of 1583 m2.g‐1 and pore volume of 0.93 cm3.g‐1. These results suggest that the earth‐abundant RH could be sustainable resources for large‐scale production of activated carbon.
Synthesis and in vitro antifungal efficiency of alginate‐stabilized Cu2O‐Cu nanoparticles against Neoscytalidium dimidiatum causing brown spot disease on dragon fruit plants (Hylocereus undatus)
Authors: Du Bui Duy , Ngoc Doan Thi Bich , Thang Nguyen Duy , Tuan Le Nghiem Anh , Thach Bui Dinh , Hien Nguyen Quoc
Published: February 2020

Cu2O‐Cu nanoparticles (Cu2O‐Cu NPs) stabilized by alginate have been developed for using as a plant fungicide. The antifungal effect of Cu2O‐Cu NPs against Neoscytalidium dimidiatum fungus causing brown spot disease in dragon fruit plants was investigated. Transmission electron microscopy (TEM) was used to assess the morphology and size of Cu2O‐CuNPs. The average diameter of spherical Cu2O‐Cu NPswas determined to be 5.4 ± 0.4 nm. Furthermore, the Cu2O‐CuNPs stabilized in alginate were also characterized by Fourier transform infrared (FT‐IR) and X‐ray diffraction (XRD) analysis. Especially, the prepared Cu2O‐Cu NPs/alginate showed high antifungal efficiency (~100 %) against Neoscytalidium dimidiatum with 30 ppm concentration copper. The obtained results showed that Cu2O‐Cu NPs stabilized in alginate have great potential in the development of nanomaterials for plant fungicide applications.
Synthesis of Valsartan as drug for the treatment of hypertension
Authors: Van Chien Tran , Anh Nguyen The , Thao Tran Thi Phuong , Phuong Le Dac , Tham Pham Thi , Tung Nguyen Quang , Van Loc Tran
Published: February 2020

The synthesis of valsartan (1), one of the most currently used pharmaceutical agent in antihypertensive therapy, was described through five steps in an overall yield of 54 % starting from 4’‐methyl‐2‐cyanobiphenyl (2). The key step involved tetrazole ring formation catalyzed by Lewis acid. The structures of synthesized compounds were confirmed by means of NMR and MS spectroscopíe.
Study on the effect of modified and unmodified silica on the properties of natural rubber vulcanizates
Authors: Quang Nguyen Trong , Hung Dang Viet , Chuong Bui , Nam Hoang , Yen Nguyen Thi
Published: February 2020

In the article, the effects of silica (silicon oxide) on some properties of natural rubber (NR) were studied. Silica used are unmodified (SiKBT) and modified with triethoxi silane propyl tetrasunfite (SiBT). It is shown SiBT increases vulcanization network density (VND), so it enhances strength and elastic properties of NR. In contrary, SiKBT decreases VND and reduces, but has almost no effect on strength of NR. Silica, both modified and unmodified, are assumed to improve network regularity of NR that change thermal degradation behavior of materials and keep the strength of NR‐SiKBT compound unchanged.
Electrochemical properties of antimony lead electrode in gelled electrolyte prepared by liquid glass and sulfuric acid using polyacrylamide together with polyaniline
Authors: Binh Phan Thi , Van Anh Nguyen Thi , Thuy Mai Thi Thanh , Xuan Mai Thi , Thanh Luong Thi
Published: February 2020

Gelled electrolyte is made at different temperatures based on liquid glass and sulfuric acid using two organic additives such as polyacrylamide and polyaniline. The antimony lead electrode is used to study the electrochemical properties of gelled electrolyte through cyclic voltammetry, electrochemical impedance and ionic conductivity determination. The results showed that the gelled electrolyte made at low temperature is in a more favorable form of gel than that at high temperature, the ability to extract water was also overcome. The resistance of charge transfer of lead electrodes operating in an gelled electrolyte environment is all lower than that in sulfuric acid (d = 1.26 g /cm3), in which the presence of PANi together with PAM is recorded as the smallest. When the lead electrode was anodized, the simultaneous formation of PbO with PbSO4 did not appear due to the presence of PANi.
An insight QSPR‐based prediction model for stability constants of metal‐thiosemicarbazone complexes using MLR and ANN methods
Authors: Quang Nguyen Minh , Nhung Nguyen Thi Ai , Van Tat Pham
Published: February 2020

In the present investigation, the stability constants (logβ12) of complexes (ML2) between metal ions (M) and thiosemicarbazones (L) were used as an endpoint in the quantitative structure‐property relationship (QSPR) approaches. The molecular descriptors of the experimental complexes were calculated from the conformation with the lowest binding free energy by means of semi‐empirical PM7 method. QSPR models were developed by using multivariate linear regression (MLR) and artificial neural network methods (ANN). The best QSPR models found out three important descriptors as knotp, Cosmo Area and Hmin in the metal‐thiosemicarbazones complexation. The final QSPRMLR model had shown satisfactory statistical performance; training (R2train) and prediction (Q2LOO) determination coefficient of 0.9274 and 0.8784, respectively. Meanwhile, the statistical results of QSPRANN model received the value of 0.9844 and 0.9898. The models also ratified strict statistical validation tests (Q2test) for external predictivity with the QSPRMLR and QSPRANN value of 0.8321 and 0.8953, respectively. A series of new metal‐thiosemicarbazones complexes were designed based on the descriptor of the models and predicted the stability constants of the complexes.
Theoretical exploitation of donor‐acceptor ability in low‐valent group‐14 elements complexes [E(PPh3)2 → SiH2]2+ (E = C to Pb) using energy decomposition analysis
Authors: Loan Huynh Thi Phuong , Van Duc Hoang , Quang Duong Tuan , Cong Vo Thanh , Van Tat Pham , Trung Nguyen Tien , Nhung Nguyen Thi Ai
Published: February 2020

The structure and bonding of complexes containing subvalent group‐14 elements [E(PPh3)2 → SiH2]2+ (Si‐EP) with E = C to Pb have been researched using charge‐ and EDA‐NOCV methods. The optimized equilibrium geometries for complexes have the most stable structure which has been found for carbone ligand CP as the nearly end‐on bonded form in Si‐CP. In contrast to this, the heavier ligands SiP to PbP in the heavier complexes Si‐SiP to Si‐PbP exhibit strongly side‐on manners. Bond dissociation energies, ‐De (kcal.mol‐1), increase from Si‐CP to the stronger bonded complexes Si‐SiP to Si‐PbP. EDA‐NOCV calculations revealed that the donation [E(PPh3)2 → SiH2]2+ displays the significant σ‐interactions of the ligands while the π‐electron sharing exhibits the charges transfer between E(PPh3)2 and SiH22+. Bonding analysis indicated that the Si‐E bond results from the decrease in the donation [E(PPh3)2 → SiH2]2+ and electrostatic attraction. The investigated complexes possessed E(PPh3)2 → SiH22+ strong σ‐donors and E(PPh3)2 ↔ SiH22+ π‐π electrons shared between the two fragments.
Lupan‐type triterpenoids from the stems of Salacia chinensis L. (Celastraceae) and their α‐glucosidase inhibitory activities
Authors: Truc Duong Thi Thanh , Vy Cao Thi Ha , Phu Dang Hoang , Hoang Nguyen Minh , Nhan Nguyen Trung
Published: February 2020

Six lupan‐type triterpenoids: 29‐norlupan‐3,20‐dione (1), 3β‐hydroxy‐29‐norlupan‐20‐one (2), betulonic acid (3), salacianol (4), 30‐hydroxylup‐20(29)‐en‐3‐one (5), and lup‐20(29)‐ene‐3β,30‐diol (6) have been isolated from the CHCl3‐soluble fraction of the stem of Salacia chinensis L. (Celastraceae). Their chemical structures were elucidated based on the NMR spectroscopic analysis and comparison with the literatures. Compounds (5) and (6) showed very weak α‐glucosidase inhibitory activity with the IC50 values of 211.5 and 246.8 μM, respectively.
Unraveling the antioxidant potential of thiamine: Thermochemical and kinetics studies in aqueous phase using DFT
Authors: Nga Nguyen Thi Thuy , Quang Dao Duy
Published: February 2020

The scavenging mechanism of thiamine (or vitamin B1) towards HO• and HOO• radicals has been revisited using density functional theory (DFT) at the M05‐2X/6‐311++G (d,p) level of theory. Enthalpies and Gibbs free energies of four common antioxidant reactions, i.e. formal hydrogen transfer (FHT), proton transfer (PT), single electron transfer (SET) and radical adduct formation (RAF), have been systematically calculated in the aqueous phase. Potential energy profiles accompanied with the optimized structures of all transition states (TS) and intermediate ones were also established. As a result, thiamine represents as a potent antioxidant notably via RAF mechanism with the lowest ΔH0 values at C12 position equal to ‐37.5 and ‐9.2 kcal/mol towards HO• and HOO• radicals, respectively. The reactions are also favorable with ΔG0 values of ‐28.8 and 2.8 kcal/mol, respectively. The order of the decrease in preponderance of the studied mechanism is as follows: RAF > FHT > SET > PT. The scavenging reactivity towards HO• radical is considerably higher than the one toward HOO• radical as expected. In comparing with trolox and ascorbic acid, their antioxidant potential could be classified in the decreasing order: ascorbic acid > thiamine > trolox.
Influence of oxygen concentration, feed gas flow rate and air humidity on the output of ozone produced by corona discharge
Authors: Cuong Le Cao , Nghi Nguyen Hoang , Dieu Tran Vinh , Oanh Doan Thi Yen , Vuong Dang Duc
Published: February 2020

Ozone (trioxygen) shows a lack of stability and quickly breaks down to dioxygen, meaning that ozone in any way can not be stored. It is therefore necessary to produce ozone on site where it is used. This leads to the idea of having an ozone generator with high efficiency. Ozone generator is an electrical device to convert oxygen as feed gas into ozone. Besides electrical parameters, feed gas plays an important role for ozone output. Feed gas for an ozone generator may be ambient air, dry air or oxygen rich gas. The influence of air humidity, oxygen concentration, flow rates of feed gas and their effects on ozone output of the corona discharge ozone generator have been investigated. For small‐scale ozone production (i.e. one hundred grams per hour or less), using oxygen produced by pressure swing adsorption method (PSA) is considered to be a reasonable solution. The authors intend to connect the studies with the practical reality of using low‐powered ozone generators in tropical area with high humidity condition.
Evaluation of electrocatalysis behavior of Fe3O4 magnetic nanoparticles on oxidation of Bisphenol A as the first step for its detection
Authors: Duy Pham Khac , Dang Vu Hai , Tien Nguyen Ngoc , Yen Pham Thi Hai , Ha Vu Thi Thu
Published: February 2020

A paste electrochemical sensor, based on a Fe3O4 modified carbon paste electrode, has been developed for investigation of Bisphenol A (BPA) oxidation in phosphate buffer solution (PBS) pH 7. In this study, it figures out that Fe3O4 reveals the best electrocatalysis on oxidation of Bisphenol A at ratio of C powder/Fe3O4/parafine oil = 76/4/20. With this composition, the BPA oxidation current recorded is 1.70 times higher than that with no Fe3O4 in CPE. It is applicable to develop an electrochemical sensor with proper amount of Fe3O4 in the paste in order to enhancement the signals of BPA during its analysis.
Gas sensing properties of CuFe2O4 nanoparticles prepared by spray co‐precipitation method
Authors: Hoa Pham Thi Thanh , Duong Nguyen Phuc , Loan To Thanh , Anh Luong Ngoc , Hong Nguyen Minh
Published: February 2020

CuFe2O4 nanoparticles were prepared by using spray co‐precipitation method and annealed at 600°C. Crystal structure, microstructure and cation distribution of the sample were determined by applying of Rietveld refinement method based on synchrotron X‐ray diffraction data. Morphology was characterized by field emission scanning electron microscopy. The results indicated that the sample is single phase with inverse cubic spinel structure. Particle size was identified to be about 10 nm. The gas‐sensing properties of the copper nanoparticles were studied by using H2S as the analytic gas. It was found that the sensor based on the CuFe2O4 nanoparticles has good response in a large operating temperature range and even at near‐room temperature. The gas sensing mechanism of the studied material was discussed in detailed.
Nitrification of high levels of ammonia in groundwater using fixed‐bed biofiltration technique
Authors: Ha Nguyen Thanh , Khanh Dao Duy , Ngan Huu Thi , Quang Tran Huu , Huong Pham Lan , Hung Duong Tuan
Published: February 2020

Groundwater ammonia pollution is well investigated worldwide as well as in Viet Nam. The products of its conversion process, namely nitrite and nitrate, cause the toxicity of ammonia in water. In addition, the existence of ammonia in water causes the modification of water taste and smell, increases the risk of heterotrophic and contagious microorganism presence. Biofilm technique has been being applied to treat the ammonia in the groundwater recently. In this present study, fixed‐bed biofiltration technique was implemented to remove the ammonia at high concentration of 20‐50 mgN/L. The results indicated that the effluent reached the standard of domestic and drinking water quality (the ammonia concentration < 3 mgN/L) at all investigated ammonia concentrations. The specific nitrification rate of the microbial carrier used reached the maximum value of about 3.76 kgN.m‐3.day‐1 with the hydraulic retention time lower than 0.4 h and feed ammonia concentration of about 50 mgN/L. The biomass density in biofiltration column before experimental implementation was about 1000 mg/L.
The immunologic Warburg effect: Evidence and therapeutic opportunities in autoimmunity
Authors: Kornberg Michael D.
Published: February 2020

Pro‐inflammatory signals induce metabolic reprogramming in innate and adaptive immune cells of both myeloid and lymphoid lineage, characterized by a shift to aerobic glycolysis akin to the Warburg effect first described in cancer. Blocking the switch to aerobic glycolysis impairs the survival, differentiation, and effector functions of pro‐inflammatory cell types while favoring anti‐inflammatory and regulatory phenotypes. Glycolytic reprogramming may therefore represent a selective vulnerability of inflammatory immune cells, providing an opportunity to modulate immune responses in autoimmune disease without broad toxicity in other tissues of the body. The mechanisms by which aerobic glycolysis and the balance between glycolysis and oxidative phosphorylation regulate immune responses have only begun to be understood, with many additional insights expected in the years to come. Immunometabolic therapies targeting aerobic glycolysis include both pharmacologic inhibitors of key enzymes and glucose‐restricted diets, such as the ketogenic diet. Animal studies support a role for these pharmacologic and dietary therapies for the treatment of autoimmune diseases, and in a few cases proof of concept has been demonstrated in human disease. Nonetheless, much more work is needed to establish the clinical safety and efficacy of these treatments.

This article is categorized under:

Biological Mechanisms > Metabolism

Translational, Genomic, and Systems Medicine > Translational Medicine

Biological Mechanisms > Cell Signaling
Dilaton portal in strongly interacting twin Higgs models
Authors: Ahmed Aqeel , Dillon Barry M. , Najjari Saereh
Published: February 2020

Abstract

We consider a strongly interacting twin Higgs (SITH) model where an ultraviolet completion of twin Higgs mechanism is realized by a strongly coupled approximately scale invariant theory. Besides the Standard Model (SM) and twin sectors, the low energy effective theory contains a relatively light scalar called a dilaton — the pseudo Goldstone boson of spontaneously broken scale invariance. The dilaton provides a unique portal between the SM and twin sectors whose phenomenology could provide an important probe of the twin Higgs mechanism. As a concrete example, we consider a holographic twin Higgs model where the role of the dilaton is played by the radion. The phenomenology of this model is fully determined by a few parameters and our analysis concludes that at the HL-LHC (14 TeV) and HE-LHC (27 TeV) with 3000 fb−1 most of the natural parameter space can be probed.
A Diagrammatic Analysis of Two-Body Charmed Baryon Decays with Flavor Symmetry
Authors: Zhao H.J. , Wang Yan-Li , Hsiao Y.K. , Yu Yao
Published: February 2020

Abstract

We study the two-body anti-triplet charmed baryon decays based on the diagrammatic approach with SU(3) flavor symmetry. We extract the two W -exchange effects as EB and E' that contribute to the $$ {\Lambda}_c^{+}\to {\Xi}^0{K}^{+} $$

Λ
c
+

→

Ξ
0

K
+

decay, together with the relative phases, where EB gives the main contribution. Besides, we find that $$ \mathcal{B}\left({\Lambda}_c^{+}\to p{\pi}^0\right)=\left({0.8}_{-0.8}^{+0.9}\right)\times {10}^{-4} $$
B

Λ
c
+

→
p

π
0

=

0.8

−
0.8

+
0.9

×

10

−
4

,which is within the experimental upper bound. Particularly, we obtain $$ \mathcal{B}\left({\Xi}_c^{+}\to {\Xi}^0{\pi}^{+}\right)=\left(9.3\pm 3.6\right)\times {10}^{-3} $$
B

Ξ
c
+

→

Ξ
0

π
+

=

9.3
±
3.6

×

10

−
3

, $$ \mathcal{B}\left({\Xi}_c^0\to {\Xi}^{-}{\pi}^{+},{\Lambda}^0{\overline{K}}^0\right)=\left(19.3\pm 2.8,8.3\pm 5.0\right)\times {10}^{-2} $$
B

Ξ
c
0

→

Ξ
−

π
+

Λ
0

K
¯

0

=

19.3
±
2.8

8.3
±
5.0

×

10

−
2

and $$ \mathcal{B}\left({\Xi}_c^0\to {\Xi}^{-}{K}^{+}\right)=\left(5.6\pm 0.8\right)\times {10}^{-4} $$
B

Ξ
c
0

→

Ξ
−

K
+

=

5.6
±
0.8

×

10

−
4

, which all agree with the data. For the singly Cabibbo suppressed $$ {\Lambda}_c^{+} $$

Λ
c
+

decays, we predict that $$ \mathcal{B}\left({\Lambda}_c^{+}\to n{\pi}^{+}, p\eta \hbox{'},{\Sigma}^{+}{K}^0\right)=\left(7.7\pm 2.0,7.1\pm 1.4,19.1\pm 4.8\right)\times 10-4 $$
B

Λ
c
+

→
n

π
+

pη
'

Σ
+

K
0

=

7.7
±
2.0

7.1
±
1.4

19.1
±
4.8

×
10
−
4
, which are accessible to the experiments at BESIII, BELLEII and LHCb.
Stability of neutral minima against charge breaking in the Higgs triplet model
Authors: Ferreira P. M. , Gonçalves B. L.
Published: February 2020

Abstract

We analyse the possibility of charge breaking minima developing in the Higgs triplet model, and under what conditions they are deeper than charge-preserving ones. Analytical expressions relating the depth of minima of different types are deduced. A global symmetry of the model leads to increased stability for charge-preserving vacua. However, if that symmetry is broken by a soft term, deeper charge-breaking minima may occur more easily. We identify the vev configurations most likely to produce charge breaking minima.
A 1d Up Approach to Conformal Geometric Algebra: Applications in Line Fitting and Quantum Mechanics
Authors: Lasenby Anthony N.
Published: February 2020

We discuss an alternative approach to the conformal geometric algebra (CGA) in which just a single extra dimension is necessary, as compared to the two normally used. This is made possible by working in a constant curvature background space, rather than the usual Euclidean space. A possible benefit, which is explored here, is that it is possible to define cost functions for geometric object matching in computer vision that are fully covariant, in particular invariant under both rotations and translations, unlike the cost functions which have been used in CGA so far. An algorithm is given for application of this method to the problem of matching sets of lines, which replaces the standard matrix singular value decomposition, by computations wholly in Geometric Algebra terms, and which may itself be of interest in more general settings. Secondly, we consider a further perhaps surprising application of the 1d up approach, which is to the context of a recent paper by Joy Christian published by the Royal Society, which has made strong claims about Bell’s Theorem in quantum mechanics, and its relation to the sphere $$S^7$$S7 and the exceptional group $$E_8$$E8, and proposed a new associative version of the division algebra normally thought to require the octonians. We show that what is being discussed by Christian is mathematically the same as our 1d up approach to 3d geometry, but that after the removal of some incorrect mathematical assertions, the results he proves in the first part of the paper, and bases the application to Bell’s Theorem on, amount to no more than the statement that the combination of two rotors from the Clifford Algebra Cl(4, 0) is also a rotor.
Angular measures and Birkhoff orthogonality in Minkowski planes
Authors: Naszódi Márton , Prokaj Vilmos , Swanepoel Konrad
Published: February 2020

Let x and y be two unit vectors in a normed plane $$\mathbb {R}^2$$

R

2

. We say that x is Birkhoff orthogonal to y if the line through x in the direction y supports the unit disc. A B-measure (Fankhänel in Beitr Algebra Geom 52(2):335–342, 2011) is an angular measure $$\mu $$
μ
on the unit circle for which $$\mu (C)=\pi /2$$

μ
(
C
)
=
π
/
2

whenever C is a shorter arc of the unit circle connecting two Birkhoff orthogonal points. We present a characterization of the normed planes that admit a B-measure.
Some Examples of Projective and c-projective Compactifications of Einstein Metrics
Authors: Dunajski Maciej , Gover A. Rod , Waterhouse Alice
Published: February 2020

We construct several examples of compactifications of Einstein metrics. We show that the Eguchi–Hanson instanton admits a projective compactification which is non-metric, and that a metric cone over any (pseudo)-Riemannian manifolds admits a metric projective compactification. We construct a para-c-projective compactification of neutral signature Einstein metrics canonically defined on certain rank-naffine bundlesMovern-dimensional manifolds endowed with projective structures.