bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and catalytic properties for olefin polymerization of new vanadium complexes containing silsesquioxane ligands with different denticity
Authors: Białek Marzena , Pochwała Monika , Franczyk Adrian , Czaja Krystyna , Marciniec Bogdan 
Published: February 2017

AbstractA series of new vanadium‐silsesquioxanes (2a − 2d) was prepared by reacting VCl4 with not fully condensed silsesquioxanes (having from one to four silanol groups) and evaluated as pre‐catalysts in olefin polymerization. The activation of 2a − 2d with EtAlCl2 generated highly active catalysts for ethylene polymerization, yielding high molar mass polymers with narrow dispersity. Ultra‐high molar mass polyethylenes, Mw up to 4 × 106 g mol−1, were obtained with methylaluminoxane and Al(iBu)3/[Ph3C][B(C6F5)4] as activators. Upon treatment with methylaluminoxane and boron compounds, all vanadium pre‐catalysts were active in 1‐octene polymerization as well, and produced isotactic‐rich poly(1‐octene)s with moderate monomer conversion (up to 23%). The polymerization parameters were optimized and the effect of the silsesquioxane structure on the catalytic activity and polymer properties was studied. © 2017 Society of Chemical Industry
Efficient protocol for quantum Monte Carlo calculations of hydrogen abstraction barriers: Application to methanol
Authors: Swann Ellen T. , Coote Michelle L. , Barnard Amanda S. , Per Manolo C. 
Published: February 2017

AbstractAccurate calculation of hydrogen abstraction reaction barriers is a challenging problem, often requiring high level quantum chemistry methods that scale poorly with system size. Quantum Monte Carlo (QMC) methods provide an alternative approach that exhibit much better scaling, but these methods are still computationally expensive. We describe approaches that can significantly reduce the cost of QMC calculations of barrier heights, using the hydrogen abstraction of methanol by a hydrogen atom as an illustrative example. By analysing the combined influence of trial wavefunctions and pseudopotential quadrature settings on the barrier heights, variance, and time‐step errors, we devise a simple protocol that minimizes the cost of the QMC calculations while retaining accuracy comparable to large‐basis coupled cluster theory. We demonstrate that this protocol is transferable to other hydrogen abstraction reactions.
Text steganography: a novel character‐level embedding algorithm using font attribute
Authors: Ramakrishnan Bala Krishnan , Thandra Prasanth Kumar , Srinivasula A. V. Satya Murty 
Published: February 2017

AbstractText Steganography uses text documents as cover medium to communicate the secret messages, covertly, by making unnoticeable distortions in the cover medium. Character‐Level Embedding Technique (CLET), a variant of text steganography, embeds a secret character by serially marking/distorting an identical character in the cover medium. Hence, these techniques suffer from low embedding capacity as the occurrence of certain alphabets in a text document is not uniform/guaranteed. In addition, identification of the marked cover character itself can reveal the hidden secret. This makes the CLET a less preferable choice. To overcome the aforementioned shortcomings, this paper proposes a novel CLET by introducing the Frequency Normalization Set in combination with the Character and String Mapping. The combination allows a low occurring character to get embedded in several cover characters, and thereby boosts its embedding probability. In addition, the combination also ensures the uniform embedding probability of secret characters. A font attribute called the character spacing is used to embed the secret. Experiments were conducted to investigate the embedding capacity, uniformity in embedding probability and frequency profile of stego characters of the proposed method. A comparison of the proposed method with the existing CLET algorithms is also provided. Various applications and the security aspects of the proposed method have also been discussed. Copyright © 2017 John Wiley & Sons, Ltd.
2D Squaraine‐Linked Polymers with High Lithium Storage Capacity Using the First Principle Methods
Authors: Huang Ling , Cao Gengyu 
Published: February 2017

AbstractLithium storage in two‐dimensional squaraine‐linked covalent organic frameworks (2D SQ‐COPs: SQ‐COP‐1, SQ‐COP‐2 and SQ‐COP‐3, respectively constructed by squaraine linker and small heterocyclic molecule nodes B3O3, H3B3N3 and C3N3), have been studied by using the first principle methods. For the adsorption of multiple Li atoms, there is no Li2 dimer or cluster formation in SQ‐COPs, but Li−O bonds formation in SQ‐COP‐1 and SQ‐COP‐3. Accumulated Li atoms in Lin@SQ‐COPs will be arranged to produce regular 2D hexagonal packed configurations due to the effects of confined space. Bader analysis reveals charge transfer from Li atoms to SQ‐COPs, indicating high lithiation. Among 2D SQ‐COPs, SQ‐COP‐1 shows better conductivity than SQ‐COP‐2, and maintains stable adsorption configuration compared with SQ‐COP‐3. Furthermore, dynamical calculations indicate that Li atom prefers to move across the 1D pores of SQ‐COP‐1, overcoming a very low energy barrier, which further enhances Li storage capacity. Such good Li storage capacity in 2D metal‐free SQ‐COPs might lead to a promising and environmental‐friendly application in Li ion batteries.
Base‐Free Palladium‐Catalyzed Hydrodechlorination of Aryl Chlorides with Pinacol Borane
Authors: Yamamoto Yutaro , Nogi Keisuke , Yorimitsu Hideki , Osuka Atsuhiro 
Published: February 2017

AbstractBase‐free palladium‐catalyzed reactions of aryl chlorides with pinacol borane have been found to give the hydrodechlorinated products while similar reactions of aryl halides with pinacol borane in the presence of a base were reported to result in borylation. The base‐free conditions offer reasonable functional group compatibility. Experimental studies suggest that smooth and selective hydride transfer from pinacol borane to arylpalladium chloride under base‐free conditions is promoted by a strong interaction between the Lewis acidic boron and the chlorine on the palladium.
Market‐based control for linear structures using symplectic theory
Authors: Li Hong‐Nan , Song Jian‐Zhu , Li Gang 
Published: February 2017

SummaryMarket‐based control (MBC) theory is a type of analogy approach between the behaviors of the free economy market and system control area. The accuracy of the algorithm is mainly determined by the supply and demand models, which are determined by the internal model parameters. In the present study, a deterministic method is proposed to improve the parameters in the models based on symplectic theory by giving the index function and introducing the dual vector so that the dynamic equation is transformed from the Lagrange to Hamilton system. In contrast to the traditional method, symplectic theory describes parameters from a new perspective without trial values, and the model parameters are only related to their own characteristics of the structural vibration system to facilitate practical application. The MBC stability is also deduced based on symplectic theory, which can be applied not only to the time‐invariant MBC system but also to the time‐varying system. To verify the effectiveness of the designed MBC controller, the control strategy is used for a 3‐story structure and a 20‐story structure. The numerical example shows that the deduction of the MBC strategy is effective.
Fisetin‐induced apoptosis of human oral cancer SCC‐4 cells through reactive oxygen species production, endoplasmic reticulum stress, caspase‐, and mitochondria‐dependent signaling pathways
Authors: Su Chen‐Hsuan , Kuo Chao‐Lin , Lu Kung‐Wen , Yu Fu‐Shun , Ma Yi‐Shih , Yang Jiun‐Long , Chu Yung‐Lin , Chueh Fu‐Shin , Liu Kuo‐Ching , Chung Jing‐Gung 
Published: February 2017

AbstractOral cancer is one of the cancer‐related diseases in human populations and its incidence rates are rising worldwide. Fisetin, a flavonoid from natural products, has been shown to exhibit anticancer activities in many human cancer cell lines but the molecular mechanism of fisetin‐induced apoptosis in human oral cancer cells is still unclear; thus, in this study, we investigated fisetin‐induced cell death and associated signal pathways on human oral cancer SCC‐4 cells in vitro. We examined cell morphological changes, total viable cells, and cell cycle distribution by phase contrast microscopy and flow cytometry assays. Reactive oxygen species (ROS), Ca2+, mitochondria membrane potential (ΔΨm), and caspase‐8, ‐9, and ‐3 activities were also measured by flow cytometer. Results indicate that fisetin induced cell death through the cell morphological changes, caused G2/M phase arrest, induction of apoptosis, promoted ROS and Ca2+ production, and decreased the level of ΔΨm and increased caspase‐3, ‐8, and ‐9 activities in SCC‐4 cells. DAPI staining and DNA gel electrophoresis were also used to confirm fisetin‐induced cell apoptosis in SCC‐4 cells. Western blotting also found out that Fisetin increased the proapoptotic proteins such as Bax and Bid and decreased the antiapoptotic proteins such as Bcl‐2. Furthermore, results also showed that Fisetin increased the cytochrome c, AIF, and Endo G release from mitochondria in SCC‐4 cells. We also used ATF‐6α, ATF‐6β, GADD153, and GRP78 which indicated that fisetin induced cell death through ER stress. Based on those observations, we suggest that fisetin induced cell apoptosis through ER stress, mitochondria‐, and caspase‐dependent pathways.
Inhibitory effects of Leucaena leucocephala on the metastasis and invasion of human oral cancer cells
Authors: Chung Hsiao‐Hang , Chen Mu‐Kuan , Chang Yu‐Chao , Yang Shun‐Fa , Lin Chia‐Chieh , Lin Chiao‐Wen 
Published: February 2017

AbstractOral cancer is one of the most common cancers worldwide, and metastasis is recognized as a major factor causing its low survival rate. The inhibition of metastasis progress and the improvement of the survival rate for oral cancer are critical research objectives. Leucaena leucocephala from the mimosa branch Leucaena genus is native to Central and South America and has been used as a traditional remedy for treating various disorders. Previous studies have demonstrated antioxidant, anti‐inflammatory as well as anticancer properties of L. leucocephala plant materials. However, the molecular mechanism underlying the anticancer effect induced by L. leucocephala remains unclear. In this study, we investigated the effect of L. leucocephala extract (LLE) on SCC‐9 and SAS oral cancer cells and examined the potential inhibitory mechanisms involved. The results indicated that LLE attenuated the migration and invasion abilities of both SCC‐9 and SAS cells by reducing the activity and protein expression of matrix metalloproteinases‐2 (MMP‐2). Regarding mitogen‐activated protein kinase (MAPK) pathways, the phosphorylation of ERK1/2 and p38 exhibited a significant inhibitory effect in the presence of LLE. The application of ERK inhibitor and p38 inhibitor confirmed that both signalling transduction pathways were involved in the inhibition of cell metastasis. These data indicate that L. leucocephala could be a potent therapeutic agent for the prevention and treatment of oral cancer and a prominent plant source for anticancer research in the future.
Estimating biomass of berries consumed by gray wolves
Authors: Gable Thomas D. , Windels Steve K. , Bruggink John G. 
Published: February 2017

ABSTRACTGray wolves (Canis lupus) consume berries and other wild fruits seasonally when available or abundant. However, a method to convert percent frequency of occurrence or percent volume of berries in wolf scats to percent biomass has not yet been developed. We used estimates of the average number of blueberry (Vaccinium spp.) seeds in 10 individual wolf scats collected in and adjacent to Voyageurs National Park, Minnesota, USA, along with published values of the number of seeds per blueberry and blueberry masses to estimate that a wolf scat containing only berries equated to an average of 0.468 kg of berries consumed. We recommend using this berry conversion factor (0.468 kg/scat) to convert the percent frequency of occurrence or percent volume of berries and other wild fruits to percent biomass when estimating wolf diets from scats. © 2017 The Wildlife Society.
Emodin, a natural inhibitor of protein kinase CK2, suppresses growth, hyphal development, and biofilm formation of Candida albicans
Authors: Janeczko Monika , Masłyk Maciej , Kubiński Konrad , Golczyk Hieronim 
Published: February 2017

AbstractEmodin (1,3,8‐trihydroxy‐6‐methyl‐anthraquinone) is a natural secondary plant product, originally isolated from the rhizomes of Rheum palmatum. Many reports show its diuretic, vasorelaxant, antibacterial, antiviral, anti‐ulcerogenic, immunosuppressive, hepatoprotective, anti‐inflammatory and anticancer potential. Emodin is a pleiotropic molecule capable of interacting with several major molecular targets, e.g. NF‐κB, AKT/mTOR and STAT3. The compound can also act as an inhibitor of some protein kinases, with special affinity to protein kinase CK2. The aim of the presented report was to evaluate antifungal properties of emodin and its activity towards CK2 isolated from Candida cells. Our studies revealed that the compound suppressed growth of the cells of reference strains as well as clinical Candida strains, with minimal inhibitory concentration and minimal fungicidal concentration values between 12.5 and 200 μg/mL. Moreover, at a low concentration, the compound was able to effectively stop hyphal formation, thus showing a distinct antivirulent potential. Interestingly, we showed that emodin added to Candida culture inhibited the phosphorylation of many cellular proteins, presumably owing to the inhibition of protein kinase CK2. Notably, the enzyme isolated from the Candida cells was susceptible to emodin with IC50 of 2.8 μg/mL. Indeed, our computational modelling revealed that emodin was able to occupy the ATP‐binding pocket of CK2. Copyright © 2017 John Wiley & Sons, Ltd.
Effects of acetoacetyl-CoA synthase expression on production of farnesene in Saccharomyces cerevisiae
Authors: Tippmann Stefan , Ferreira Raphael , Siewers Verena , Nielsen Jens , Chen Yun 
Published: February 2017

Abstract
Efficient production of sesquiterpenes in Saccharomyces cerevisiae requires a high flux through the mevalonate pathway. To achieve this, the supply of acetyl-CoA plays a crucial role, partially because nine moles of acetyl-CoA are necessary to produce one mole of farnesyl diphosphate, but also to overcome the thermodynamic constraint imposed on the first reaction, in which acetoacetyl-CoA is produced from two moles of acetyl-CoA by acetoacetyl-CoA thiolase. Recently, a novel acetoacetyl-CoA synthase (nphT7) has been identified from Streptomyces sp. strain CL190, which catalyzes the irreversible condensation of malonyl-CoA and acetyl-CoA to acetoacetyl-CoA and, therefore, represents a potential target to increase the flux through the mevalonate pathway. This study investigates the effect of acetoacetyl-CoA synthase on growth as well as the production of farnesene and compares different homologs regarding their efficiency. While plasmid-based expression of nphT7 did not improve final farnesene titers, the construction of an alternative pathway, which exclusively relies on the malonyl-CoA bypass, was detrimental for growth and farnesene production. The presented results indicate that the overall functionality of the bypass was limited by the efficiency of acetoacetyl-CoA synthase (nphT7). Besides modulation of the expression level, which could be used as a means to partially restore the phenotype, nphT7 from Streptomyces glaucescens showed clearly higher efficiency compared to Streptomyces sp. strain CL190.
Pathophysiologic relationship between Alzheimer's disease, cerebrovascular disease, and cardiovascular risk: A review and synthesis
Authors: Santos Cláudia Y. , Snyder Peter J. , Wu Wen‐Chih , Zhang Mia , Echeverria Ana , Alber Jessica 
Published: February 2017

AbstractAs the population ages due to demographic trends and gains in life expectancy, the incidence and prevalence of dementia increases, and the need to understand the etiology and pathogenesis of dementia becomes ever more urgent. Alzheimer's disease (AD), the most common form of dementia, is a complex disease, the mechanisms of which are poorly understood. The more we learn about AD, the more questions are raised about our current conceptual models of disease. In the absence of a cure or the means by which to slow disease progress, it may be prudent to apply our current knowledge of the intersection between AD, cardiovascular disease, and cerebrovascular disease to foster efforts to delay or slow the onset of AD. This review discusses our current understanding of the epidemiology, genetics, and pathophysiology of AD, the intersection between AD and vascular causes of dementia, and proposes future directions for research and prevention.
Coping as a mediator of stress and psychotic-like experiences
Authors: Ered A. , Gibson L.E. , Maxwell S.D. , Cooper S. , Ellman L.M. 
Published: February 2017

AbstractBackground:There is evidence that individuals along the whole psychosis continuum have increased responsiveness to stress; however, coping responses to stressors have not been extensively explored in subthreshold psychotic symptoms.Methods:In 454 undergraduates, psychotic-like experiences (PLEs) were evaluated using the positive items of the Prodromal Questionnaire. Perceived stress and traumatic life events were assessed using the Life Events Checklist and Perceived Stress Scale, and coping was measured using the Brief COPE. We also examined whether different coping styles mediated the relationship between perceived stress and PLEs, as well as whether different coping styles mediated the relationship between traumatic life events and PLEs.Results:Both number of traumatic life events and current level of perceived stress were significantly associated with PLEs. These relationships were both mediated by higher levels of maladaptive coping.Conclusions:Results have the potential to inform treatment strategies, as well as inform targets for exploration in longitudinal studies of those at risk for psychosis.
The relationship of bullying and physical violence to mental health and academic performance
Authors: AlBuhairan Fadia , Abbas Oraynab Abou , Sayed Donna El , Badri Motasim , Alshahri Sulieman , Vries Nanne de 
Published: February 2017

Background and objectives:
Bullying and physical violence are serious public health concerns witnessed during adolescence and are associated with several health and behavioral problems that can persist into adulthood. The relationship between bullying/physical violence and mental health/academic performance in Saudi Arabia is unknown. This study aims at filling this gap through identifying the association of these health risk behaviors and mental health and academic performance.

Materials and methods:
A cross-sectional national survey was conducted in Saudi Arabia between 2011 and 2012. Adolescents attending intermediate and secondary schools were invited to participate through a multi-stage, stratified, cluster random sampling technique. A self-administered questionnaire was used to collect data. Data were analyzed using chi-square tests to identify associations, and odds ratios were calculated.

Results:
A total of 9073 students participated. Twenty-six percent of adolescents reported exposure to bullying in the preceding 30 days, and one out of every three adolescents reported exposure to physical violence at school during the past year. More males than females, and more older adolescents were exposed to bullying. Exposure to physical violence and bullying were both associated with higher odds of having more frequent symptoms of depression and anxiety. Those exposed to physical violence were at higher odds of having poorer academic performance.

Conclusion:
Bullying and physical violence among adolescent students in Saudi Arabia is prevalent and deserves special attention due to its harmful impact on the other aspects of students' wellbeing.
Multiplicity of periodic solution with prescribed energy to singular dynamical systems
Authors: Terracini Susanna 
Published: February 2017

We prove the existence of multiple solutions with prescribed energy for a class of dynamical systems with singular potentials.

Résumé
Nous démontrons l’existence d’une multiplicité de solutions périodiques à énergie fixée pour une classe de systèmes dynamiques dont les potentiels sont singuliers.
On nonviscous compressible fluids in a time-dependent domain
Authors: Secchi Paolo 
Published: February 2017

We study the Euler equations for a nonviscous compressible barotropic fluid in a time-dependent domain of the three-dimensional space. We prove the existence of a unique local in time classical solution.

Résumé
On considère les équations d’Euler pour un fluide non visqueux, compressible et barotropique dans un domaine de l’espace dépendant du temps. On démontre l’existence locale d’une unique solution classique.
Nonlinear symmetric positive systems
Authors: Tso Kaising 
Published: February 2017

We study the existence and uniqueness of solutions as well as their continuous dependence on given data for the boundary value problem for a general nonlinear symmetric positive system by a Nash–Hörmander iteration scheme. Results on quasilinear systems and the existence of smooth solutions which improve known results on this subject are also presented.

Résumé
A l’aide de la méthode itérative de Nash–Hörmander, nous étudions un système nonlinéaire positif symétrique et un problème de perturbation singulière. Nous obtenons des résultats d’existencé, d’unicite et de dépendance continue par rapport aux données.
EFFECT OF PRODUCTION PARAMETERS ON THE ECONOMIC FEASIBILITY OF A BIOFUEL ENTERPRISE
Authors: ZAPATA SAMUEL D. , RIBERA LUIS A. , PALMA MARCO A. 
Published: February 2017

AbstractIn order to guarantee the success of the nascent cellulose-based biofuel industry, it is crucial to identify the most economically relevant components of the biofuel production path. To this aim, an original stochastic financial model is developed to estimate the impact that different feedstock production and biofuel conversion parameters have on the probability of economic success. Estimation of the model was carried out using Monte Carlo simulation techniques along with parametric maximum likelihood estimation procedures. Results indicate that operational efficiency strategies should concentrate on improving feedstock yields and extending the feedstock growing season.
Translating Battlefield Practices to Disaster Health
Authors: Strauss-Riggs Kandra , Yeskey Kevin , Miller Aubrey , Arnesen Stacey , Goolsby Craig 
Published: February 2017

AbstractWe review aspects of the recently released National Academies of Sciences, Engineering, and Medicine report A National Trauma Care System: Integrating Military and Civilian Trauma Systems to Achieve Zero Preventable Deaths After Injury most relevant to disaster health, particularly the concepts of focused empiricism and building a learning health system. The article references battlefield success utilizing these concepts and the emerging Disaster Research Response Program. We call upon disaster health researchers to apply the report’s recommendations to their work. (Disaster Med Public Health Preparedness. 2017;11:510–511)