bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Social Support on College Students’ Mobile Phone Dependence: The Mediating Role of Security
Authors: Fu Guifang , Shi Kexin , Ye Kai
Published: February 2020

In order to further study the current situation and relationship of college students’ mobile phone dependence, social support and sense of security, a questionnaire survey was performed on 409 college students using the college students' mobile phone addiction tendency scale, social support assessment scale and sense of safety scale. The results showed that: (1) 40.24% of college students are moderate of mobile phone dependence, and 5.75% of college students had serious problem of mobile phone dependence; the social support and sense of security of college students were at the upper-middle level; there is no gender difference，no one child difference and no love difference of mobile phone dependence in college students; there is grade difference of mood change; (2) The social support and sense of security of people with high phone dependence are significantly lower than those with low phones Dependence; (3) Social dependence and sense of security have significant negative correlations and negative predictive effects on mobile phone dependence; (4) Security sense has a full mediating role between social support and mobile phone dependence, thus enhancing social support and the sense of security of college students can effectively improve their mobile phone dependence.
Teachers’ Understanding-Check Practices and Learners’ Following Orientations in EFL Classroom Interaction: A Conversation Analytic Study
Authors: Karimpour Sedigheh , Yaqubi Baqer
Published: February 2020

Classroom discourse is typically dominated by question and answer routines in which
teachers ask most of the questions, a practice constituting one of the principal ways in
which they control the discourse and push learners to contribute to classroom interaction (Brock, 1986; Walsh, 2006). Most of previous research on teachers’ questions mainly focused on identifying and discovering different question types which believed to be helpful in creating the opportunities for learners’ interactions. Drawing on conversation analysis through adopting socio-cultural perspective, this study, however, aims to examine how EFL learners orient to the teachers’ understanding-check questions in three sequential contexts (activity-boundary, post instruction and within-activity) which emerged in this study. Informed by the tenets of conversation analysis, we have observed, videotaped, and transcribed line-by-line 6 EFL teachers’ naturally-occurring classroom interaction. Analyses of 8 episodes from the data suggest that learners seemingly orient to the understanding-check questions used by their teachers as preferring no-problem, which is marked in their orientations to show no-problem responses in the preferred format and yesproblem responses in the dispreferred format. The findings of this study have implications for teacher education.
Assessment of Training Needs for Teaching at the elementary schools in Saudi Arabia
Authors: Al-Madani Feras Mohammed
Published: February 2020

The study aimed to identify Arabic language teachers' training needs in teaching my
beautiful language Textbook with regards to lesson plan, its implementation and evaluation in investigating the statistically significant differences in training needs related to gender differences, years of experience, and number of training courses attendance at the primary level in Arar, Saudi Arabia. The study employed descriptive statistics to describe mean scores of the samples, standard deviation and ANCOVA to determine the statistically significant differences among the respondents. The study tool consisted of (46) item which was divided into three areas namely; planning, implementation and evaluation. The samples were (25) male and (25) female primary school teachers. The study found that the degree of training need for planning, implementation and evaluation is high and the degree of training need for teachers in the implementation and evaluation of lessons is also high regardless of the number of training courses attended. Also it was found that the female teachers are in need of training more than the male teachers and that training need increases with the increase in the number of years of experience. The study recommended capitalizing on training project in solving the problem of teachers for training on the planning and implementation skills and the lesson evaluation of my beautiful language Textbook.
Child Human Rights Education: Barriers in Implementation
Authors: Vissing Yvonne
Published: February 2020

This article suggests comprehensive implementation of child and human rights education is a strategy to reduce risk and increase benefits to children, yet there are barriers to its implementation. This article explores the current condition of human rights education (HRE) and child
rights education (CRE) in the United States. It compares it to CRE implementation benefits globally, particularly in Wales. Exploratory pilot studies indicate that the way rights education is structured in the US does not allow young people to benefit from its potential capacity. Students
lack of rights knowledge is explored in this article. Teachers identify obstacles to rights implementation in schools. Recommendations on how to improve HRE are provided.
Time Series Analysis of Stock Market Volatility in Pakistan
Authors: Rashid Tabassam , Ismail Aisha , Rashid Kashif
Published: February 2020

The stock market in an emerging country like Pakistan has been volatile from the earliest times. This paper studies the volatility of Pakistan Stock Exchange (PSX) (using Karachi Stock Exchange 100 Index (KSE-100) as a proxy) through the application of Generalized Autoregressive Conditional Heteroscedasticity (GARCH) family models.

The sample period consists of 4831 daily observations for the 19 year trading period (from 2000 to 2019). Symmetric GARCH (2, 1), asymmetric EGARCH (1, 1), GJR-GARCH (1, 1) and APARCH (1, 1) models were used under Gaussian distributional assumptions. The results validate the empirical findings of previous studies conducted in Pakistan that log returns of KSE-100 Index are characterized by volatility clustering, time-variability, leptokurtic distribution with dominant ARCH and GARCH effects. An interesting feature of Pakistan Stock Exchange revealed by asymmetric models (used in the study) is that PSX is more volatile to good news than bad news. Moreover EGARCH (1, 1) outperforms all other models of the study on the basis of AIC/BIC criterion. However the comparison of correlations of variances predicted by three asymmetric models reveal that correlations among them are very high, with minimum correlation being 98%. This essentially means that all three asymmetric models provide a good fit to PSX.
Farm Households Food Demand and Its Determinants in Nigeria
Authors: Oluwatusin F. M. , Adekunmi A. O. , Ajiboye A. , Toluwase S. O. W. , Osundare F. O. , Abdu-Raheem K. A.
Published: February 2020

Aims: The study examined the farming households’ food demand in Nigeria by, identifying the socio-economic characteristics of the farming households, assessing the monthly expenditure share of various categories of food in the total households’ food budget, analyzing the expenditure elasticities of the food classes and examining the factors influencing food demand.

Methodology: A questionnaire was used as research instrument to elicit primary data from 120 farming households randomly selected through a multi-stage sampling method. The data analyses were done through the use of descriptive statistics and Quadratic Almost Ideal Demand System (QUAIDS) model.

Results: The results show that 61.7 percent of the household heads were men while the mean age was 45.7 years. Most (92.5%) of the household heads were educated with mean household size of 7 persons and mean monthly income of N19, 435.20. The analysis of average monthly expenditure share of various food classes demanded for by the households reveals that roots and tubers food class had the largest (48%) share of households’ total food expenditure while flesh foods and dairy products came last with just 2 percent. In addition, expenditure elasticities of the six classes of food considered indicate that  demand for roots and tubers, starchy food, fruits and vegetables and fats and oil food classes were inelastic while that of Flesh foods and dairy products and protein grains were elastic. Also it was revealed that farm households with small household sizes consume more proteinous foods. The determinants that had the expected sign and cut across all food classes were the price of individual food category and household income.

Conclusion: The study analysed the farming households’ food demand and its determinants and in order to improve the farm households’ demand for food, it is recommended that policies to prevent upward or downward swings in the prices of foods in the economy should be put in place.
Effects of Direct Costs of River Blindness Illness and Perceived Benefits of Community-directed Treatment with Ivermectin in Rural Households of Benue State, Nigeria
Authors: Ogebe F. O. , Daniel Abah , Burbwa P. A.
Published: February 2020

The study assessed households’ direct cost of Onchocerciasis illness and the perceived benefits of community-directed treatment with ivermectin in Benue State, Nigeria. A survey method was used and primary data were collected using structured questionnaires. The survey covered a period of six (6) months between June, 2019 and December, 2019. The population of the study consisted of households affected with Onchocerciasis in Benue State, Nigeria. Random sampling technique was used in selecting a sample size of 200 respondents from three Local Government Areas of Benue State. Descriptive statistics, Cost of illness approach, household expenditure model and multiple regression models were used to analyze the data. The descriptive statistics showed that majority (63.7%) of the respondents were males and married (66.7%) with average age of 48.8 years and average household size of 10 persons. The average farm size was 4.0 hectares with an annual farm income of N167, 266.16. The most perceived symptoms of onchocerciasis by the respondents were severe itching (29%), skin rashes (25.5%) and swelling (17.3%). Ivermectin was cited as the most effective treatment for onchocerciasis as 57.0% of the respondents attested to its effectiveness. The average cost of onchocerciasis illness was N77, 923.84. The direct cost of illness was estimated at N34, 503.20 per household which is high enough to stretch the already tight expenditure budgets of the poor rural households. The household expenditure model revealed negative and statistically significant relationship between onchocerciasis (health shock) and food expenditure (P<0.05), education expenditure (P<0.01) and housing expenditure (P<0.1). The study revealed a positive relationship between health consumption of affected households and household income, borrowing, sale of assets, de-saving and sale of food reserves. The study identified social and health benefits of community-directed treatment with ivermectin (CDTI). The social benefits include: Ability to work better (70.7%), acceptance by peers (52.3%) and respect in the community (47.7%) while the health benefits to the respondents were improved vision (69.4%), reduced itching (65.1%) and deworming (61.1%).The factors associated with perceived benefits of CDTI in the study area are age (P=0.029), marital status (p<0.012), length of stay in the onchocerciasis endemic community (p<0.001) and individual susceptibility to onchocerciasis infection (p<0.0001). The study recommends continuing sensitization of members of the public on the consequences of Onchocerciasis and the importance of Mectizan as curative drug. This will improve the overall health status, enhance the social interactions and increase the economic productivity of the households of North-Central Nigeria, as well as ensure food security and the development of the nation at large.
Genetic alterations of malignant pleural mesothelioma: association with tumor heterogeneity and overall survival
Authors: Quetel Lisa , Meiller Clément , Assié Jean‐Baptiste , Blum Yuna , Imbeaud Sandrine , Montagne François , Tranchant Robin , de Wolf Julien , Caruso Stefano , Copin Marie‐Christine , Hofman Véronique , Gibault Laure , Badoual Cécile , Pintilie Ecaterina , Hofman Paul , Monnet Isabelle , Scherpereel Arnaud , Le Pimpec‐Barthes Françoise , Zucman‐Rossi Jessica , Jaurand Marie‐Claude , Jean Didier
Published: February 2020

Development of precision medicine for malignant pleural mesothelioma (MPM) requires a deep knowledge of tumor heterogeneity. Histologic and molecular classifications and histo‐molecular gradients have been proposed to describe heterogeneity, but a deeper understanding of gene mutations in the context of MPM heterogeneity is required and the associations between mutations and clinical data need to be refined. We characterized genetic alterations on one of the largest MPM series (266 tumor samples), well annotated with histologic, molecular and clinical data of patients. Targeted next‐generation sequencing was performed focusing on the major MPM mutated genes and the TERT promoter. Molecular heterogeneity was characterized using predictors allowing classification of each tumor into the previously described molecular subtypes and the determination of the proportion of epithelioid‐like and sarcomatoid‐like components (E/S.scores). The mutation frequencies are consistent with literature data, but this study emphasized that TERT promoter, not considered by previous large sequencing studies, was the third locus most affected by mutations in MPM. Mutations in TERT promoter, NF2, and LATS2 were more frequent in nonepithelioid MPM and positively associated with the S.score. BAP1, NF2, TERT promoter, TP53, and SETD2 mutations were enriched in some molecular subtypes. NF2 mutation rate was higher in asbestos unexposed patient. TERT promoter, NF2, and TP53 mutations were associated with a poorer overall survival. Our findings lead to a better characterization of MPM heterogeneity by identifying new significant associations between mutational status and histologic and molecular heterogeneity. Strikingly, we highlight the strong association between new mutations and overall survival.
Classical Architectural Elements
Authors: Harby Stephen , McBroom Scot C.
Published: February 2020

The elements of classical architecture, which we inherited from the ancient Greeks, have been in constant use and continual evolution for over 2000 years. Nevertheless, in the twentieth century, beginning in the 1920s and particularly following World War II, there was a major shift in architectural theory and pedagogy which led to the abandonment of the universal use of the orders in design. In one generation the profession went from total familiarity to almost complete ignorance of the specifics of classical architecture. A small collection of architects continued to learn and to design correctly and knowingly in the classical style. The vitality of the orders as recurrent touchstone and framework for architectural expression is considerable, but the highest moments have always been those of significant transformation. The fact is that the essentials of architecture—as expounded by the Renaissance —are to be found expressed, consciously or unconsciously, throughout the architectures of the world.
Mathematical Data
Authors: Thomas T. Edward
Published: February 2020

This chapter provides selected equations and constants used for obtaining mathematical data pertinent to construction process. It presents a list of materials generally used in building construction, together with their proper weights. The architectural area of a building is the sum of the areas of the floors, measured horizontally in plan to the exterior faces of perimeter walls or to the centerline of walls separating buildings. Areas of sloping surfaces, such as staircases, bleachers, and tiered terraces, should be measured horizontally in plan. Included in the architectural volume is the actual space enclosed within the outer surfaces of the exterior of outer walls and contained between the outside of the roof and the bottom of the lowest floor, taken in full: bays, chimneys; walk tunnels; enclosed porches and balconies, including screened areas. The chapter also contains tables listing decimal equivalents for fraction, metric units commonly used in construction, and conversion factors for various quantities.
Element B: Shell
Authors:   ASTM C1193,   Sealant, Waterproofing and Restoration Institute (SWRI), Bauman William C. , Pienkny Stephan , Vanderlinden Charles W. , Fling Russell S. , Daly Leo A. , Neubauer Donald , Shapiro Walter D. ,   Krommenhoek/McKeown and Associates,   Karlsberger and Companies, Sabol Thomas A. ,   American Iron and Steel Institute,   Severud Associates, Vitullo Richard J. , Ballast David , Prasithrathsint Sukamorn , Johnson David W. ,   The Bumgardner Architects, Rankin Janet B. , Szoradi Charles A. , Wilkes Joseph A. , McDonald Timothy B. , Mazz Mark J. ,   David Nairne‐Associates Ltds., Kipp Roger W. ,   American Plywood Association, Pienkny Stefan , McGee Cline ,   Haynes Whaley Associates, Foley Robert P. ,   Precast/Prestressed Concrete Institute,   Architectural Precast Association, Dean Tom Van ,   Marble Institute of America,   Indiana Limestone Institute of America,   Cast Stone Institute, Cianfrini Rich , Swiegart Dan , Benson Tedd , Brungraber Ben , Spinu Maria , Carmody John , Selkowitz Stephen , Hayes Daniel F.C. ,   Door & Access Systems Manufacturers Association (DASMA), Davis Jarrett B. , Fehlberg Robert E. , Lee Grace S. ,   National Roofing Contractors Association, Eickelberger Valerie , Boon Rich , Miller Charlie , Parise Charles J. ,   SMACNA, Inc.,   Jones/Richards and Associates, Cobb Lawrence W. ,   Industrial Fabrics Association International, Golebiewski Anthony
Published: February 2020

Of primary importance to the shell of a building is the mediation between the exterior and interior environment. Environmental conditions to be maintained within the building influence the design of the shell. The building shell should be a major part of the sustainable strategy. Walls and other surfaces on or around buildings respond to ambient temperature change, solar radiation, wetting and drying effects from precipitation, and varying cloud cover by either increasing or decreasing in volume and therefore in linear dimension. For residential buildings in cold climates, heat loss through the enclosure may be the largest component of total energy consumption. Buildings must be properly braced to resist racking under wind and seismic loads. Shop‐fabricated wood trusses have been used in building construction since 1953, when the metal connector plate was invented. The chapter examines common floor construction assemblies and common systems used in roof construction.
AATOD, supporter of the MATE Act, fact‐checks the MAT Act
Authors: Knopf Alison
Published: February 2020

It's no secret that the American Association for the Treatment of Opioid Dependence (AATOD) is opposed to the Mainstreaming Addiction Treatment (MAT) Act — S. 2074 and H.R. 2482.
In Situ Coating Graphdiyne for High‐Energy‐Density and Stable Organic Cathodes
Authors: Li Liang , Zuo Zicheng , Wang Fan , Gao Jingchi , Cao Anmin , He Feng , Li Yuliang
Published: February 2020

The preparation of organic small‐molecule cathodes is simple and low‐cost; however, their low conductivity and molecular dissolution are two key issues that mean their energy density and power performance are far lower than those of inorganic batteries, thus hindering their practical application. To develop an effective coating technology is the key to obtain high‐performance organic batteries. A general method of in situ weaving all‐carbon graphdiyne nanocoatings is demonstrated. The graphdiyne can be conformally weaved on organic particles under mild conditions so that the conductivity is increased and the dissolution is suppressed. After weaving graphdiyne nanocoat, the active mass of the small‐molecule organic cathodes rise to 93%, thus delivering a higher energy density of 310 W h kg−1 than previously reported, and the power performance and long‐term stability are greatly improved. Additionally, this method shows great potential to become the crucial technology for fabricating organic batteries with energy density close to prevailing lithium‐ion batteries.
Conductive Hole‐Selective Passivating Contacts for Crystalline Silicon Solar Cells
Authors: Wan Lu , Zhang Cuili , Ge Kunpeng , Yang Xueliang , Li Feng , Yan Wensheng , Xu Zhuo , Yang Lin , Xu Ying , Song Dengyuan , Chen Jianhui
Published: February 2020

Defect state passivation and conductivity of materials are always in opposition; thus, it is unlikely for one material to possess both excellent carrier transport and defect state passivation simultaneously. As a result, the use of partial passivation and local contact strategies are required for silicon solar cells, which leads to fabrication processes with technical complexities. Thus, one material that possesses both a good passivation and conductivity is highly desirable in silicon photovoltaic (PV) cells. In this work, a passivation‐conductivity phase‐like diagram is presented and a conductive‐passivating‐carrier‐selective contact is achieved using PEDOT:Nafion composite thin films. A power conversion efficiency of 18.8% is reported for an industrial multicrystalline silicon solar cell with a back PEDOT:Nafion contact, demonstrating a solution‐processed organic passivating contact concept. This concept has the potential advantages of omitting the use of conventional dielectric passivation materials deposited by costly high‐vacuum equipment, energy‐intensive high‐temperature processes, and complex laser opening steps. This work also contributes an effective back‐surface field scheme and a new hole‐selective contact for p‐type and n‐type silicon solar cells, respectively, both for research purposes and as a low‐cost surface engineering strategy for future Si‐based PV technologies.
Phenotypic expansion of KMT2D‐related disorder: Beyond Kabuki syndrome
Authors: Baldridge Dustin , Spillmann Rebecca C. , Wegner Daniel J. , Wambach Jennifer A. , White Frances V. , Sisco Kathleen , Toler Tomi L. , Dickson Patricia I. , Cole F. Sessions , Shashi Vandana , Grange Dorothy K.
Published: February 2020

Pathogenic variants in KMT2D, which encodes lysine specific methyltransferase 2D, cause autosomal dominant Kabuki syndrome, associated with distinctive dysmorphic features including arched eyebrows, long palpebral fissures with eversion of the lower lid, large protuberant ears, and fetal finger pads. Most disease‐causing variants identified to date are putative loss‐of‐function alleles, although 15–20% of cases are attributed to missense variants. We describe here four patients (including one previously published patient) with de novo KMT2D missense variants and with shared but unusual clinical findings not typically seen in Kabuki syndrome, including athelia (absent nipples), choanal atresia, hypoparathyroidism, delayed or absent pubertal development, and extreme short stature. These individuals also lack the typical dysmorphic facial features found in Kabuki syndrome. Two of the four patients had severe interstitial lung disease. All of these variants cluster within a 40‐amino‐acid region of the protein that is located just N‐terminal of an annotated coiled coil domain. These findings significantly expand the phenotypic spectrum of features associated with variants in KMT2D beyond those seen in Kabuki syndrome and suggest a possible new underlying disease mechanism for these patients.
Access to Heteroleptic Fluorido‐Cyanido Complexes with a Large Magnetic Anisotropy by Fluoride Abstraction
Authors: Liu Jun‐Liang , Pedersen Kasper S. , Greer Samuel M. , Oyarzabal Itziar , Mondal Abhishake , Hill Stephen , Wilhelm Fabrice , Rogalev Andrei , Tressaud Alain , Durand Etienne , Long Jeffrey R. , Clérac Rodolphe
Published: February 2020

Silicon‐mediated fluoride abstraction is demonstrated as a means of generating the first fluorido‐cyanido transition metal complexes. This new synthetic approach is exemplified by the synthesis and characterization of the heteroleptic complexes, trans‐[MIVF4(CN)2]2− (M=Re, Os), obtained from their homoleptic [MIVF6]2− parents. As shown by combined high‐field electron paramagnetic resonance spectroscopy and magnetization measurements, the partial substitution of fluoride by cyanide ligands leads to a marked increase in the magnetic anisotropy of trans‐[ReF4(CN)2]2− as compared to [ReF6]2−, reflecting the severe departure from an ideal octahedral (Oh point group) ligand field. This methodology paves the way toward the realization of new heteroleptic transition metal complexes that may be used as highly anisotropic building‐blocks for the design of high‐performance molecule‐based magnetic materials.
Vacancy Engineering of Iron‐Doped W18O49 Nanoreactors for Low‐Barrier Electrochemical Nitrogen Reduction
Authors: Tong Yueyu , Guo Haipeng , Liu Daolan , Yan Xiao , Su Panpan , Liang Ji , Zhou Si , Liu Jian , Lu Gao Qing (Max) , Dou Shi Xue
Published: February 2020

The electrochemical nitrogen reduction reaction (NRR) is a promising energy‐efficient and low‐emission alternative to the traditional Haber–Bosch process. Usually, the competing hydrogen evolution reaction (HER) and the reaction barrier of ambient electrochemical NRR are significant challenges, making a simultaneous high NH3 formation rate and high Faradic efficiency (FE) difficult. To give effective NRR electrocatalysis and suppressed HER, the surface atomic structure of W18O49, which has exposed active W sites and weak binding for H2, is doped with Fe. A high NH3 formation rate of 24.7 μg h−1 mgcat−1 and a high FE of 20.0 % are achieved at an overpotential of only −0.15 V versus the reversible hydrogen electrode. Ab initio calculations reveal an intercalation‐type doping of Fe atoms in the tunnels of the W18O49 crystal structure, which increases the oxygen vacancies and exposes more W active sites, optimizes the nitrogen adsorption energy, and facilitates the electrocatalytic NRR.
Luminescent Metallacycle‐Cored Liquid Crystals Induced by Metal Coordination
Authors: Chen Long , Chen Changlong , Sun Yue , Lu Shuai , Huo Haohui , Tan Tianyi , Li Anquan , Li Xiaopeng , Ungar Goran , Liu Feng , Zhang Mingming
Published: February 2020

Two rhomboidal metallacycles based on metal‐coordination‐driven self‐assembly are presented. Because metal‐coordination interactions restrict the rotation of phenyl groups on tetraphenylethene units, these metallacycles were emissive both in solution and in solid state, and their aggregation‐induced emission properties were well‐retained. Moreover, the rhomboidal metallacyclic structures offer a platform for intermolecular packing beneficial for the formation of liquid crystalline phases. Therefore, although neither of building blocks shows mesogenic properties, both thermotropic and lyotropic (in DMF) mesophases were observed in one of metallacycles, indicating that mesophases could be induced by metal‐coordination interactions. This study not only reveals the mechanism for the formation of cavity‐cored liquid crystals, but also provides a convenient approach to preparing supramolecular luminescent liquid crystals, which will serve as good candidates for chemo sensors and liquid crystal displays.
Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH4 from its Hydrolytic Product
Authors: Zhu Yongyang , Ouyang Liuzhang , Zhong Hao , Liu Jiangwen , Wang Hui , Shao Huaiyu , Huang Zhenguo , Zhu Min
Published: February 2020

Sodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.
Poly(2‐Oxazoline)‐Based Functional Peptide Mimics: Eradicating MRSA Infections and Persisters while Alleviating Antimicrobial Resistance
Authors: Zhou Min , Qian Yuxin , Xie Jiayang , Zhang Wenjing , Jiang Weinan , Xiao Ximian , Chen Sheng , Dai Chengzhi , Cong Zihao , Ji Zhemin , Shao Ning , Liu Longqiang , Wu Yuequn , Liu Runhui
Published: February 2020

Peptides have important biological functions. However, their susceptibility to proteolysis limits their applications. We demonstrated here for the first time, that poly(2‐oxazoline) (POX) can work as a functional mimic of peptides. POX‐based glycine pseudopeptides, a host defense peptide mimic, had potent activities against methicillin‐resistant S. aureus, which causes formidable infections. The POX mimic showed potent activity against persisters that are highly resistant to antibiotics. S. aureus did not develop resistance to POX owning to the reactive oxygen species related antimicrobial mechanism. POX‐treated S. aureus is sensitive to common antibiotics, demonstrating no observable antimicrobial pressure or cross‐resistance in using antimicrobial POX. This study highlights POX as a new type of functional mimic of peptides and opens new avenues in designing and exploring peptide mimetics for biological functions and applications.
Dual catalytic performance of arene‐ruthenium amine complexes for norbornene ring‐opening metathesis and methyl methacrylate atom‐transfer radical polymerizations
Authors: Cruz Thais R. , Silva Eliada A. , Oliveira Douglas P. , Martins Daniele M. , Gois Patrik D.S. , Machado Antonio E.H. , Maia Pedro Ivo S. , Goi Beatriz E. , Lima‐Neto Benedito S. , Carvalho‐Jr Valdemiro P.
Published: February 2020

Arene ruthenium(II) complexes bearing the cyclic amines RuCl2(η6‐p‐cymene)(pyrrolidine)] (1), [RuCl2(η6‐p‐cymene)(piperidine)] (2), and [RuCl2(η6‐p‐cymene)(peridroazepine)] (3) were successfully synthesized. Complexes 1–3 were fully characterized by means of Fourier transform infrared, UV–visible, and NMR spectroscopy, elemental analysis, cyclic voltammetry, computational methods, and one of the complexes was further studied by single crystal X‐ray crystallography. These compounds were evaluated as catalytic precursors for ring‐opening metathesis polymerization (ROMP) of norbornene (NBE) and atom‐transfer radical polymerization (ATRP) of methyl methacrylate (MMA). NBE polymerization via ROMP was evaluated using complexes 1–3 as precatalysts in the presence of ethyl diazoacetate (EDA) under different [NBE]/[EDA]/[Ru] ratios, temperatures (25 and 50°C), and reaction times (5–60 min). The highest yields of polyNBE were obtained with [NBE]/[EDA]/[Ru] = 5000/28/1 for 60 min at 50°C. MMA polymerization via ATRP was conducted using 1–3 as catalysts in the presence of ethyl‐α‐bromoisobutyrate (EBiB) as initiator. The catalytic tests were evaluated as a function of the reaction time using the initial molar ratio of [MMA]/[EBiB]/[Ru] = 1000/2/1 at 95°C. The increase in molecular weight as function of time indicates that complexes 1–3 were able to mediate the MMA polymerization with an acceptable rate and some level of control. Differences in the rate of polymerization were observed in the order 3 > 2 > 1 for the ROMP and ATRP.
Myc and the Replicative CMG Helicase: The Creation and Destruction of Cancer
Authors: Reed Damon R. , Alexandrow Mark G.
Published: February 2020

Myc‐driven tumorigenesis involves a non‐transcriptional role for Myc in over‐activating replicative Cdc45‐MCM‐GINS (CMG) helicases. Excessive stimulation of CMG helicases by Myc mismanages CMG function by diminishing the number of reserve CMGs necessary for fidelity of DNA replication and recovery from replicative stresses. One potential outcome of these events is the creation of DNA damage that alters genomic structure/function, thereby acting as a driver for tumorigenesis and tumor heterogeneity. Intriguingly, another potential outcome of this Myc‐induced CMG helicase over‐activation is the creation of a vulnerability in cancer whereby tumor cells specifically lack enough unused reserve CMG helicases to recover from fork‐stalling drugs commonly used in chemotherapy. This review provides molecular and clinical support for this provocative hypothesis that excessive activation of CMG helicases by Myc may not only drive tumorigenesis, but also confer an exploitable “reserve CMG helicase vulnerability” that supports developing innovative CMG‐focused therapeutic approaches for cancer management.
Saccharide Insertion in Carbon Nanotube: Molecular Dynamics Simulation Studies
Authors: Lee Jeongmin , Chang Rakwoo
Published: February 2020

We have investigated the insertion process of saccharides into nanopores using atomistic molecular dynamic (MD) simulations of the model systems, which consist of three different saccharides (α‐d‐glucose, sucrose, and γ‐cyclodextrin) and carbon nanotubes (CNTs) with various diameters (13.6–21.7 Å). We have observed that unlike small saccharides such as α‐d‐glucose and sucrose, γ‐cyclodextrin shows a nonmonotonic behavior in the absorption free energy with the minimum at the CNT pore of about 16 Å in diameter. In addition, we have decomposed the system energy into several components to understand the driving force of the saccharide insertion into nanopores and found that the nonmonotonic insertion free energy is attributed to several contributions such as the dehydration and the conformational change of saccharides, van der Waals interactions among saccharides, CNT and water molecules, and the entropic effects of water molecules.
Pseudoblock of cavotricuspid isthmus via detouring gap conduction
Authors: Sekihara Takayuki , Sonoura Takuryu , Nakamura Yuka , Sunayama Isamu , Morishita Yu , Ishimi Masashi , Yamato Masashi , Yoshimura Takahiro , Yasuoka Yoshinori
Published: February 2020

To detect detouring gap conduction, as demonstrated in this case, 3‐D mapping is useful in addition to conventional methods.
Reconstitution of Food Powders Granulated with Oil‐in‐Water Emulsions
Authors: Rieder Anna , Franceschinis Erica , De Santi Martina , Realdon Nicola , Santomaso Andrea Claudio
Published: February 2020

Vegetable soups are complex mixtures containing vegetables in different percentages, thickeners, salt, fat, and emulsifying/wetting agents. When prepared as dehydrated powders in convenience foods, they need to be rehydrated before consumption and this can lead to formation of undesired lumps when carried out in hot water. Elimination of lumps and simplification of the preparation procedure were reached by granulating three different vegetable mixtures, each with a predominant vegetable (spinach, beetroot, and carrot), using an alternative liquid binder besides water. The use of an oil‐in‐water emulsion affected positively some technological properties of the dry products like granule strength and flowability, and the rehydrated soups in terms of complete dispersion in hot water. Also, the interplay between starches and soluble sugars, naturally present in vegetables, was found to impact the complete rehydration of the soups.
Correlating Solution‐ and Solid‐State Structures of Conformationally Flexible Resorcinarenes: Significance of a Sulfonyl Group in Intramolecular Self‐Inclusion
Authors: Pamuła Małgorzata , Nissinen Maija , Helttunen Kaisa
Published: February 2020

The synthesis of tetramethoxyresorcinarene podands bearing p‐toluene arms connected by ‐SO3‐ (1) and ‐CH2O‐ (2) linkers is presented herein. In the solid state, the resorcinarene podand 1 forms an intramolecular self‐inclusion complex with the pendant p‐toluene group of a podand arm, whereas the resorcinarene podand 2 does not show self‐inclusion. The conformations of the flexible resorcinarene podands in solution were investigated by variable‐temperature experiments using 1D and 2D NMR spectroscopic techniques as well as by computational methods, including a conformational search and subsequent DFT optimisation of representative structures. The 1H NMR spectra of 1 and 2 at room temperature show a single set of proton signals that are in agreement with C4v symmetry. At low temperatures, the molecules exist as a mixture of boat conformations featuring slow exchange on the NMR timescale. Energy barriers (ΔG≠298) of 55.5 and 52.0 kJ mol−1 were calculated for the boat‐to‐boat exchange of 1 and 2, respectively. The results of the ROESY experiments performed at 193 K and computational modelling suggest that in solution the resorcinarene podand 1 adopts a similar conformation to that present in its crystal structure, whereas podand 2 populates a more versatile range of conformations in solution.
DMT1 Inhibitors Kill Cancer Stem Cells by Blocking Lysosomal Iron Translocation
Authors: Turcu Andreea L. , Versini Antoine , Khene Nadjib , Gaillet Christine , Cañeque Tatiana , Müller Sebastian , Rodriguez Raphaël
Published: February 2020

Cancer stem cells (CSC) constitute a cell subpopulation in solid tumors that is responsible for resistance to conventional chemotherapy, metastasis and cancer relapse. The natural product Salinomycin can selectively target this cell niche by directly interacting with lysosomal iron, taking advantage of upregulated iron homeostasis in CSC. Here, inhibitors of the divalent metal transporter 1 (DMT1) have been identified that selectively target CSC by blocking lysosomal iron translocation. This leads to lysosomal iron accumulation, production of reactive oxygen species and cell death with features of ferroptosis. DMT1 inhibitors selectively target CSC in primary cancer cells and circulating tumor cells, demonstrating the physiological relevance of this strategy. Taken together, this opens up opportunities to tackle unmet needs in anti‐cancer therapy.
Polar Organofluorine Substituents: Multivicinal Fluorines on Alkyl Chains and Alicyclic Rings
Authors: O'Hagan David
Published: February 2020

This Review outlines the progression, primarily of our own work, but with important contributions from other labs, on the synthesis and properties of multiple vicinally fluorinated alkyl chains and rings. Chain conformations of individual diastereoisomers with ‐CHF‐ at adjacent carbons are influenced by stereoelectronic factors associated with the polar C−F bond and the polarised geminal hydrogens. Generally, the chain will prefer a conformation which acts to minimise overall molecular polarity, and where the C−F bonds orient away from each other. However, when vicinal fluorine atoms are positioned on a ring then conformations are more constrained. The ring will adopt optimal conformations such as a chair in cyclohexane and then C−F bonds can be introduced with a stereochemistry that forces parallel (axial) orientations. In the case of cyclohexane, 1,3‐diaxial arrangements of C−F bonds impart considerable polarity to the ring, resulting in an electronegative ‘fluorine face’ and an electropositive ‘hydrogen face’. For all‐syn 1,2,3,4,5,6‐hexafluorocyclohexane, this arrangement generates an unusually polar aliphatic ring system. Most recently the concept has been extended to the preparation of all‐syn 1,2,3‐trifluorocyclopropanes, a rigid ring system with fluorine atoms on one face and hydrogens on the other. Lipophilicity Log P values of such compounds indicate that they are significantly more polar than their parent alicyclic hydrocarbons and give some positive indication for a future role of such substituents in medicinal chemistry. Expanding to such a role will require access to improved synthesis methods to these motifs and consequently access to a broader a range of building blocks, however some exciting new methods have emerged recently and these are briefly reviewed.
Generating Excess Protons in Microsolvated Acid Clusters under Ambient Conditions: An Issue of Configurational Entropy versus Internal Energy
Authors: Pérez de Tudela Ricardo , Marx Dominik
Published: February 2020

Acid dissociation, and thus liberation of excess protons in small water droplets, impacts on diverse fields such as interstellar, atmospheric or environmental chemistry. At cryogenic temperatures below 1 K, it is now well established that as few as four water molecules suffice to dissociate the generic strong acid HCl, yet temperature‐driven recombination sets in simply upon heating that cluster. Here, the fundamental question is posed of how many more water molecules are required to stabilize a hydrated excess proton at room temperature. Ab initio path integral simulations disclose that not five, but six water molecules are needed at 300 K to allow for HCl dissociation independently from nuclear quantum effects. In order to provide the molecular underpinnings of these observations, the classical and quantum free energy profiles were decomposed along the dissociation coordinate in terms of the corresponding internal energy and entropy profiles. What decides in the end about acid dissociation, and thus ion pair formation, in a specific microsolvated water cluster at room temperature is found to be a fierce competition between classical configurational entropy and internal energy, where the former stabilizes the undissociated state whereas the latter favors dissociation. It is expected that these are generic findings with broad implications on acid–base chemistry depending on temperature in small water assemblies.
Intratumor heterogeneity could inform the use and type of postoperative adjuvant therapy in patients with head and neck squamous cell carcinoma
Authors: Mroz Edmund A. , Patel Krupal B. , Rocco James W.
Published: February 2020

Background

After surgery for head and neck squamous cell carcinoma (HNSCC), decisions regarding adjuvant radiotherapy (RT) or chemoradiotherapy (CRT) are based on staging and the presence of high‐risk pathology. Because higher mutant allele tumor heterogeneity (MATH; a measure of intratumor genetic heterogeneity) is associated with shorter overall survival (OS) in patients with HNSCC, the authors sought to determine whether MATH analysis might further inform these decisions.

Methods

Adjuvant therapy–associated relationships between MATH and OS were analyzed for 389 patients with HNSCC who were treated surgically. Data were obtained from The Cancer Genome Atlas and analyzed with Cox proportional hazards multiple regression accounting for 7 other patient characteristics.

Results

The relationship between MATH and OS differed with adjuvant therapy in a way that could inform therapy decisions. Adjuvant RT alone was found to provide substantial benefit for patients having high‐MATH tumors (RT vs no adjuvant therapy: hazard ratio, 0.29 [95% CI, 0.17‐0.51]) but no benefit for those having low‐MATH tumors. In contrast, adjuvant CRT provided no benefit beyond that of adjuvant RT for patients with high‐MATH tumors but substantially improved OS among patients with low‐MATH tumors (CRT vs no adjuvant therapy: hazard ratio, 0.34 [95% CI, 0.15‐0.78]).

Conclusions

The results of the current analysis suggested that patients with HNSCC with high‐MATH tumors who underwent surgical treatment could benefit from adjuvant RT, even when current clinical guidelines indicate otherwise. The addition of adjuvant chemotherapy for patients with high‐MATH tumors would not be indicated. Adding chemotherapy might be necessary to radiosensitize low‐MATH tumors to adjuvant RT. This potential predictive role of tumor MATH analysis should be evaluated in prospective clinical trials.
Improving the impact of power efficiency in mobile cloud applications using cloudlet model
Authors: Tawalbeh Lo'ai , Tawalbeh Mohammad A. , Aldwairi Monther
Published: February 2020

The applications and services of Information and Communication Technologies are becoming a very essential part of our daily life. In addition, the spread of advanced technologies including the cloud and mobile cloud computing (MCC), wireless communication, and smart devices made it easy to access the internet and utilize unlimited number of services. For example, we use mobile applications to carry out critical tasks in hospitals, education, finance, and many others. This wide useful usage makes the smart devices an essential component of our daily life. The limited processing capacity and battery lifetime of mobile devices are considered main challenges. This challenge is increased when executing intensive applications. The MCC is believed to overcome these limitations. There are many models in MCC and one efficient model is the cloudlet‐based computing. In this model, the mobile devices users communicate with the cloudlets using cheaper efficient technologies, and offload the job requests to be executed on the cloudlet rather than on the enterprise cloud or on the device itself. In this article, we investigated the cloudlet‐based MCC architecture, and more specifically, the cooperative cloudlets model. In this model, the applications that require intensive computations such as image processing are offloaded from the mobile device to the nearest cloudlet. If the task cannot be accomplished at this cloudlet, the cloudlets cooperate with each other to accomplish the user request and send the results back to the user. To demonstrate the efficiency of this cooperative cloudlet‐based MCC model, we conducted real experiments that execute selected applications such as: object code recognition, and array sorting to measure the delay and power consumption of the cloudlet‐based system. Moreover, suitable cloud/mobile cloud simulators such as CloudSim and MCCSim will be used to perform simulation experiments and obtain time and power results.
Unambiguous method for DLL BOC signals tracking
Authors: Feneniche Wafa , Rouabah Khaled , Flissi Mustapha , Atia Salim , Mezaache Salah Eddine , Meguellati Sabrina
Published: February 2020

In this paper, we propose an efficient method for eliminating ambiguity in the acquisition and tracking processes of binary offset carrier (BOC)‐modulated signals. Our contribution is realized in two stages. The first one is based on the use, at the receiver end, of optimized locally generated subcarrier sequences to get a completely unambiguous composite correlation function (CF). This first stage is used to initialize and control the second stage of the proposed method designed on the basis of a maximum likelihood algorithm (MLA) to mitigate, specifically, multipath (MP) effect. In fact, the idea is to combine, in this second stage, the received signal (affected by noise and MP) with a set of locally generated ideal BOC(m,n)‐modulated signals, which are delayed and weighted by the MLA‐estimated parameters of delays, amplitudes, and phases of all the MP signals, to obtain an unambiguous CF with better performance. The simulation results, based on MATLAB tool, have demonstrated that the proposed method effectively eliminates the ambiguity problem. Besides, a comparative study with several methods has shown that the proposed method grants better performance than the most popular techniques.