bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracellular Modulation of Excited‐State Dynamics in a Chromophore Dyad: Differential Enhancement of Photocytotoxicity Targeting Cancer Cells
Authors: Kolemen Safacan , Işık Murat , Kim Gyoung Mi , Kim Dabin , Geng Hao , Buyuktemiz Muhammed , Karatas Tugce , Zhang Xian‐Fu , Dede Yavuz , Yoon Juyoung , Akkaya Engin U.
Published: March 2015

The photosensitized generation of reactive oxygen species, and particularly of singlet oxygen [O2(a1Δg)], is the essence of photodynamic action exploited in photodynamic therapy. The ability to switch singlet oxygen generation on/off would be highly valuable, especially when it is linked to a cancer‐related cellular parameter. Building on recent findings related to intersystem crossing efficiency, we designed a dimeric BODIPY dye with reduced symmetry, which is ineffective as a photosensitizer unless it is activated by a reaction with intracellular glutathione (GSH). The reaction alters the properties of both the ground and excited states, consequently enabling the efficient generation of singlet oxygen. Remarkably, the designed photosensitizer can discriminate between different concentrations of GSH in normal and cancer cells and thus remains inefficient as a photosensitizer inside a normal cell while being transformed into a lethal singlet oxygen source in cancer cells. This is the first demonstration of such a difference in the intracellular activity of a photosensitizer.
Assembly of Fluorinated Quaternary Stereogenic Centers through Catalytic Enantioselective Detrifluoroacetylative Aldol Reactions
Authors: Xie Chen , Wu Lingmin , Han Jianlin , Soloshonok Vadim A. , Pan Yi
Published: March 2015

A Cu‐catalyzed asymmetric detrifluoroacetylative aldol addition reaction of 2‐fluoro‐1,3‐diketones/hydrates to aldehydes in the presence of base and chiral bidentate ligand was developed. The reaction was carried out under convenient conditions and tolerated a wide range of substrates, resulting in fluorinated quaternary stereogenic α‐fluoro‐β‐hydroxy ketone products with good chemical yields, diastereo‐ and enantioselectivities. This catalytic asymmetric detrifluoroacetylative aldol addition reaction provides a new approach for the preparation of biologically relevant products containing CF quaternary stereogenic centers.
Strukturen und Biosynthese der Corvolether – Sesquiterpene aus dem Actinomyceten Kitasatospora setae
Authors: Rabe Patrick , Pahirulzaman Khomaizon A. K. , Dickschat Jeroen S.
Published: March 2015

Wir berichten über die funktionale Charakterisierung einer Sesquiterpencyclase aus Kitasatospora setae. Das Enzym konvertiert den Sesquiterpen‐Vorläufer Farnesyldiphosphat (FPP) in zwei zuvor unbekannte und instabile Sesquiterpenether, für die wir die Trivialnamen Corvolether A und B vorschlagen. Beide Verbindungen wurden gereinigt und ihre Strukturen durch ein‐ und zweidimensionale NMR‐Spektroskopie aufgeklärt. Ein Biosynthesemechanismus für die FPP‐Cyclisierung durch die Corvolether‐Synthase wurde vorgeschlagen. Die Ergebnisse aus Inkubationsexperimenten der Corvolether‐Synthase mit isotopenmarkierten Vorläufern waren in Übereinstimmung mit diesem Mechanismus, wohingegen alternative Mechanismen ausgeschlossen werden konnten.
A Trigonal‐Pyramidal Erbium(III) Single‐Molecule Magnet
Authors: Brown Andrew J. , Pinkowicz Dawid , Saber Mohamed R. , Dunbar Kim R.
Published: March 2015

Given the recent advent of mononuclear single‐molecule magnets (SMMs), a rational approach based on lanthanides with axially elongated f‐electron charge cloud (prolate) has only recently received attention. We report herein a new SMM, [Li(THF)4[Er{N(SiMe3)2}3Cl]⋅2 THF, which exhibits slow relaxation of the magnetization under zero dc field with an effective barrier to the reversal of magnetization (ΔEeff/kB=63.3 K) and magnetic hysteresis up to 3 K at a magnetic field sweep rate of 34.6 Oe s−1. This work questions the theory that oblate or prolate lanthanides must be stabilized with the appropriate ligand framework in order for SMM behavior to be favored.
Quantitative Structural Constraints for Organic Powders at Natural Isotopic Abundance Using Dynamic Nuclear Polarization Solid‐State NMR Spectroscopy
Authors: Mollica Giulia , Dekhil Myriam , Ziarelli Fabio , Thureau Pierre , Viel Stéphane
Published: March 2015

A straightforward method is reported to quantitatively relate structural constraints based on 13C–13C double‐quantum build‐up curves obtained by dynamic nuclear polarization (DNP) solid‐state NMR to the crystal structure of organic powders at natural isotopic abundance. This method relies on the significant gain in NMR sensitivity provided by DNP (approximately 50‐fold, lowering the experimental time from a few years to a few days), and is sensitive to the molecular conformation and crystal packing of the studied powder sample (in this case theophylline). This method allows trial crystal structures to be rapidly and effectively discriminated, and paves the way to three‐dimensional structure elucidation of powders through combination with powder X‐ray diffraction, crystal‐structure prediction, and density functional theory computation of NMR chemical shifts.
Immobilization of palladium(II)‐containing bis(imidazolium) ligand on ion‐exchange resins: efficient and reusable catalysts for CC coupling reactions
Authors: Pahlevanneshan Zari , Moghadam Majid , Mirkhani Valiollah , Tangestaninejad Shahram , Mohammadpoor‐Baltork Iraj , Khosropour Ahmad R.
Published: March 2015

Suzuki reactions catalysed by a palladium(II) complex of a functionalized bis(imidazolium) ligand, PdII(BIM), immobilized on Dowex 50 WX8 and Amberlite IR‐120 ion‐exchange resins as heterogeneous, recyclable and active catalysts are reported. The catalysts, PdII(BIM)@Amberlite IR‐120 and PdII(BIM)@Dowex 50 WX8, were characterized using Fourier transform infrared and diffuse‐reflectance UV–visible spectroscopies and scanning electron microscopy. These heterogeneous catalysts are oxygen‐insensitive and air‐ and moisture‐stable in CC coupling reactions, and are reusable several times without significant loss of their catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.
Co(II) and Fe(II) phthalocyanines: synthesis, investigation of their catalytic activity towards phenolic compounds and electrochemical behaviour
Authors: Saka Ece Tugba , Biyiklioglu Zekeriya
Published: March 2015

4‐[(1‐Benzylpiperidin‐4‐yl)oxy]‐substituted cobalt(II) and iron(II) phthalocyanine complexes were synthesized and their catalytic activity towards various phenolic compounds was investigated. Converting from environmentally harmful phenolic compounds into less harmful oxidation products using phthalocyanines makes this study attractive. This catalysis is feasible and time‐saving in terms of procedure and the best oxidation conditions determined. Electrochemical studies were also carried out using cyclic voltammetry and square wave voltammetry techniques. Voltammetric analyses of the synthesized phthalocyanine complexes supported their proposed structures. Copyright © 2015 John Wiley & Sons, Ltd.
Effects of monovalent and multivalent ions on the stability of a polyelectrolyte complex with entrapped surfactants
Authors: Gao Yan , Chowdhury Monica Roy , Liang Jenn‐Tai , Dhar Prajnaparamita
Published: March 2015

In this article, we report the effects of nine different monovalent and multivalent salts on the particle size and stability of refined, positively charged polyelectrolyte complexes (PECs) with entrapped surfactant. Dynamic light scattering and ζ potential measurements of these polymeric particles as a function of various salt concentrations showed that both counter ions and co‐ions induced a concentration‐dependent increase in the particle size and a decrease in the ζ potential. We found that the anion concentration where the particle size doubled and the maximum anion concentration beyond which particle precipitation occurred (Ca,max) demonstrated a power law dependence on the anion valence. Moreover, for anions of the same valence but different hydration radio, Ca,max decreased in the following order: NO3 → Cl → HPO42− > SO42− > PO43−. However, unlike the case of hard colloids where co‐ions have relatively little effect on particle interactions, the co‐ions also increased the hydrodynamic radii of our PECs in the following order: K+ ≈ Na+ > Ca2+ > Mg2+ > Al3+. Furthermore, we found that the entrapped surfactants were shielded from the adverse effect of multivalent ions; this established that the monovalent and multivalent ions interacted with the polyelectrolyte shells of the PEC. This behavior was in contrast with the effect of salts on mixtures containing the polyelectrolyte and surfactant components, where the addition of salts typically causes an interaction with the individual components. Because several biomedical and technological applications involving PECs require saline environments, our studies provide insight into how small ions influence the PEC stability in applications involving varying salinities. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42099.
Carboxymethylcellulose (CMC) as a model compound of cellulose fibers and polyamideamine epichlorohydrin (PAE)–CMC interactions as a model of PAE–fibers interactions of PAE‐based wet strength papers
Authors: Siqueira Eder J. , Salon Marie‐Christine B. , Belgacem Mohamed N. , Mauret Evelyne
Published: March 2015

Carboxymethylcellulose (CMC) is a cellulose derivative obtained by the carboxymethylation of some hydroxyl groups in the cellulose macromolecules. In this article, we use CMC as a model compound of cellulose fibers to study polyamineamide epichlorohydrin (PAE)–fibers interactions during the preparation of PAE‐based wet strength papers. The main advantages of the use of CMC to replace cellulose fibers are its water‐soluble character and the homogeneous reaction medium during mixing with PAE resin. Based on 13C cross‐polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) and Fourier transformed infra‐red (FTIR) spectroscopy, we prove the formation of ester bonds in PAE–CMC films boosted by a thermal posttreatment at 105°C for 24 h. These ester bonds are derived from a thermally induced reaction between carboxyl groups in the CMC structure and azetidinium ions (AZR) in the PAE resin. PAE‐based handsheets were prepared from 100% Eucalyptus fibers. After preparation, some samples were thermally posttreated (TP) at 130°C for 10 min and stored under controlled conditions (25°C and 50% relative humidity or RH). For lowest PAE dosage, storage of the not thermally posttreated (NTP) PAE‐based handsheets does not allow them to reach the tensile strength values of TP PAE‐based handsheets (at 130°C for 10 min), but the difference in terms of breaking length remains low. For the highest PAE addition level, NTP and TP PAE‐based handsheets exhibit close values of the breaking length from 30 days of storage under controlled conditions (25°C and 50% RH). When a thermal posttreatment is applied, the wet strength development of PAE‐based papers is a combined effect of homo‐ and co‐cross‐linking mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42144.
Studies on the effect of silicon carbide nanoparticles on the thermal, mechanical, and biodegradation properties of poly(caprolactone)
Authors: Mdletshe Thembinkosi S. , Mishra Shivani B. , Mishra Ajay K.
Published: March 2015

In this work, silicon carbide (SiC) nanoparticles were used to reinforce polycaprolactone (PCL). The nanocomposites were prepared by melt‐mixing followed by mould extrusion. The effect of increased SiC loading on the thermal, mechanical, and dynamic mechanical properties was investigated using differential scanning calorimetry, tensile testing, and dynamic mechanical analysis (DMA), respectively. The morphology and chemical interactions were carried out by scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR), respectively. The SiC nanoparticles were fairly well dispersed in the PCL matrix. FTIR indicated that there was no chemical interaction between PCL and SiC. The presence of SiC nanoparticles influenced the crystallization behavior of PCL, whereas there was no significant influence on thermal degradation behavior of PCL. Generally, the mechanical properties of the nanocomposite increased with an increase in nanoparticle content. The DMA results showed that the presence of SiC improved the storage modulus of PCL especially at higher SiC loading. Thermogravimetric analysis showed a very small influence of SiC on the thermal stability of PCL. Moreover, the glass transition temperature (Tg) of the nanocomposites shifted to lower temperatures compared to that of neat PCL. The crystal structure was not significantly influenced by the presence of SiC. The biodegradation process of PCL in soil environment delayed in the presence of SiC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42145.
Influence of the pentaerythritol phosphate melamine salt content on the combustion and thermal decomposition process of intumescent flame‐retardant ethylene–vinyl acetate copolymer composites
Authors: Zhang Feng , Sun Wenying , Wang Yong , Liu Bensheng
Published: March 2015

Pentaerythritol phosphate melamine salt (PPMS) as a single‐molecule intumescent fire retardant was synthesized and characterized. The influence of the PPMS content on the combustion and thermal decomposition processes of intumescent‐flame‐retardant (IFR) ethylene–vinyl acetate copolymer (EVA) composites was studied by limiting oxygen index (LOI) measurement, UL 94 rating testing, cone calorimetry, thermogravimetric analysis, and scanning electron microscopy. The LOI and UL 94 rating results illustrate that PPMS used in EVA improved the flame retardancy of the EVA composites. The cone calorimetry test results show that the addition of PPMS significantly decreased the heat‐release rate, total heat release, and smoke‐production rate and enhanced the residual char fire performance of the EVA composites. The IFR–EVA3 composite showed the lowest heat‐release and smoke‐production rates and the highest char residue; this means that the IFR–EVA3 composite had the best flame retardancy. The thermogravimetry results show that the IFR–EVA composites had more residual char than pure EVA; the char residue yield increased with increasing PPMS content. The analysis results for the char residue structures also illustrated that the addition of PPMS into the EVA resin helped to enhance the fire properties of the char layer and improve the flame retardancy of the EVA composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42148.
Nonisothermal curing kinetics of epoxy resin composite utilizing Ga (III) xanthate as a latent catalyst
Authors: Vagvala Tarun Chand , Kapil Gaurav , Pandey Shyam S. , Ogomi Yuhei , Hayase Shuzi
Published: March 2015

Cure kinetics and curing mechanism of epoxy resin composite utilizing gallium (III) xanthate as a latent catalyst was investigated and compared with the commercial latent catalyst UCAT3512T formulation. Nonisothermal differential scanning calorimetric technique at different heating rates was employed to investigate the kinetic parameters. Activation energy was determined using Kissinger's and Flynn‐Wall‐Ozawa methods. Ga (III) xanthate was found to possess superior latent properties compared with UCAT3512T since the activation energy value obtained was higher for epoxy resin composite consisting of Ga (III) xanthate than UCAT3512T. Friedman's isoconversional method was utlizied to for kinetic modeling. An autocatalytic model was found to be successful in describing the curing reaction for both of the formulations. The calculated conversion rate as a function of temperature obtained by solving the autocatalytic equation showed a very good fit with experimental values. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42149.
Combined puncture/cutting of elastomer membranes by pointed blades: Characterization of mechanisms
Authors: Triki Ennouri , Nguyen‐Tri Phuong , Gauvin Chantal , Azaiez Meriam , Vu‐Khanh Toan
Published: March 2015

The simultaneous puncture and cutting behavior of elastomers was investigated by pointed blades. Puncture/cutting tests by three‐pointed blades were performed with different elastomer membranes, including butyl, neoprene, and nitrile rubbers. The fracture mechanisms associated to puncture/cutting were investigated. The quantitative material properties which control the puncture/cutting resistance are obtained. The results have showed that the crack growth propagation is controlled by the material viscoelastic and the fracture behaviors of material, as well as the friction between the pointed blade and material. As evidenced from the fracture mechanism analysis, the friction contributes to the resistance of material against the simultaneous puncture and cutting by a factor of more than 60%. It has also been that the penetration force and the global fracture energy depend on the blade tip angle, the cutting edge angle, and the blade lubrication. Finally, an analysis of mixed‐mode fracture based on puncture/cutting by pointed blades has been described. The crack propagation is a synergistic interaction between the fracture modes I and III. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42150.
Optimization of the silane treatment of cellulosic fibers from eucalyptus wood using response surface methodology
Authors: Rojo Ester , Alonso M. Virginia , Del Saz‐Orozco Belén , Oliet Mercedes , Rodriguez Francisco
Published: March 2015

Viscose cellulosic fibers from eucalyptus wood were treated with organosilanes to introduce specific functionalities on the fibers and enhance their wettability and adhesion with phenolic matrices in composites. Modeling procedures were employed to optimize the conditions of the treatments of the fibers with the silanes (3‐aminopropyl) trimethoxysilane (APS) and 3‐(2‐aminoethylamino) propyltrimethoxysilane (AAPS). The analyzed responses were relative intensities of the bands 1565/897 and 1120/897 cm−1, measured by Fourier transform infrared spectroscopy, and the silicon amount incorporated into the cellulosic fibers, which was determined by energy dispersive X‐ray analysis. In addition, surface morphology of the silane treated fibers was observed using scanning electron microscopy. The treatments of the cellulosic fibers with 2.2% APS for 120 min and 1.5% AAPS for 100 min were selected as optimums. According to contact angle measurements, both treatments enhanced the wettability between the fibers and a resol‐type phenolic resin, revealing the possible use of the silane treated fibers as reinforcement in phenolic composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42157.
The development of a virtual 3D model of the renal corpuscle from serial histological sections for E‐learning environments
Authors: Roth Jeremy A. , Wilson Timothy D. , Sandig Martin
Published: March 2015

Histology is a core subject in the anatomical sciences where learners are challenged to interpret two‐dimensional (2D) information (gained from histological sections) to extrapolate and understand the three‐dimensional (3D) morphology of cells, tissues, and organs. In gross anatomical education 3D models and learning tools have been associated with improved learning outcomes, but similar tools have not been created for histology education to visualize complex cellular structure–function relationships. This study outlines steps in creating a virtual 3D model of the renal corpuscle from serial, semi‐thin, histological sections obtained from epoxy resin‐embedded kidney tissue. The virtual renal corpuscle model was generated by digital segmentation to identify: Bowman's capsule, nuclei of epithelial cells in the parietal capsule, afferent arteriole, efferent arteriole, proximal convoluted tubule, distal convoluted tubule, glomerular capillaries, podocyte nuclei, nuclei of extraglomerular mesangial cells, nuclei of epithelial cells of the macula densa in the distal convoluted tubule. In addition to the imported images of the original sections the software generates, and allows for visualization of, images of virtual sections generated in any desired orientation, thus serving as a “virtual microtome”. These sections can be viewed separately or with the 3D model in transparency. This approach allows for the development of interactive e‐learning tools designed to enhance histology education of microscopic structures with complex cellular interrelationships. Future studies will focus on testing the efficacy of interactive virtual 3D models for histology education. Anat Sci Educ 8: 574–583. © 2015 American Association of Anatomists.
Improving relevance feedback‐based query expansion by the use of a weighted word pairs approach
Authors: Colace Francesco , De Santo Massimo , Greco Luca , Napoletano Paolo
Published: March 2015

In this article, the use of a new term extraction method for query expansion (QE) in text retrieval is investigated. The new method expands the initial query with a structured representation made of weighted word pairs (WWP) extracted from a set of training documents (relevance feedback). Standard text retrieval systems can handle a WWP structure through custom Boolean weighted models. We experimented with both the explicit and pseudorelevance feedback schemas and compared the proposed term extraction method with others in the literature, such as KLD and RM3. Evaluations have been conducted on a number of test collections (Text REtrivel Conference [TREC]‐6, ‐7, ‐8, ‐9, and ‐10). Results demonstrated that the QE method based on this new structure outperforms the baseline.
Relationship between ocean mean temperatures and Indian summer monsoon rainfall
Authors: Ali M. M. , Nagamani P. V. , Sharma N. , Venu Gopal R. T. , Rajeevan M. , Goni G. J. , Bourassa Mark A.
Published: March 2015

Besides improving the understanding of the physics of the challenging problem of monsoon prediction, it is necessary to evaluate the efficiency of the input parameters used in models. Sea‐surface temperature (SST) is the only oceanographic parameter applied in most of the monsoon forecasting models, which many times do not represent the heat energy available to the atmosphere. We studied the impacts of ocean mean temperature (OMT), representing the heat energy of the upper ocean, and SST on the all India summer monsoon rainfall through a statistical relation during 1993–2013 and found that OMT has a better link than SST.
Enhanced power generation in annular single‐chamber microbial fuel cell via optimization of electrode spacing using chocolate industry wastewater
Authors: Noori Parisa , Najafpour Darzi Ghasem
Published: March 2015

Development and practical application of microbial fuel cell (MFC) is restricted because of the limitations such as low power output. To overcome low power limitation, the optimization of specific parameters including electrode materials and surface area, electrode spacing, and MFC's cell shape was investigated. To the best of our knowledge, no investigation has been reported in the literature to implement an annular single‐chamber microbial fuel cell (ASCMFC) using chocolate industry wastewater. ASCMFC was fabricated via optimization of the stated parameters. The aspects of ASCMFC were comprehensively examined. In this study, the optimization of electrode spacing and its impact on performance of the ASCMFC were conducted. Reduction of electrode spacing by 46.15% (1.3–0.7 cm) resulted in a decrease in internal resistance from 100 to 50 Ω, which enhanced the power density and current output to 22.898 W/m3 and 6.42 mA, respectively. An optimum electrode spacing of 0.7 cm was determined. Through this paper, the effects of these parameters and the performance of ASCMFC are also evaluated.
Risk of cancer among children with birth defects: A novel approach
Authors: Dawson Somer , Charles Adrian K. , Bower Carol , de Klerk Nicholas H. , Milne Elizabeth
Published: March 2015

Background

Associations between birth defects (BDs) and childhood cancers have been studied previously and have identified several specific birth defect‐cancer associations. No studies have examined the risk after exclusion of known associations.

Methods

We analyzed data from high‐quality population‐based registers of BDs and cancers for Western Australian births 1982 to 2007. The cohort comprised 641,036 babies still alive at 90 days. Two experts independently reviewed all 120 births with a BD and a cancer to determine whether the cancer was congenital, caused by the BD, known to be associated with the BD or otherwise. These categories were used in sensitivity analyses. Cox regression was used to estimate hazard ratios (HRs) for any cancer and specific cancers associated with any BD and specific BDs.

Results

The HR for any cancer among children with any BD was 1.96 (95% confidence interval, 1.59–2.43). The HR for any cancer among children with a BD not known to be related to a cancer (n = 57) was 1.19 (95% confidence interval, 0.91–1.56). The HR for the latter association among children diagnosed with cancer before 5 years of age was 1.74 (95% confidence interval, 1.28–2.37).

Conclusion

This novel approach aimed to prevent inflated HRs arising from reverse causation, and allow identification of associations beyond those already well documented. Larger studies using this method are needed to explore currently undocumented associations between BDs and cancers. Birth Defects Research (Part A) 103:284–291, 2015. © 2015 Wiley Periodicals, Inc.
rs1801133C>T polymorphism in MTHFR is a risk factor for nonsyndromic cleft lip with or without cleft palate in the Brazilian population
Authors: de Aguiar Pamella Kelly Farias , Coletta Ricardo D. , de Oliveira Allane Maria Lacerda Ferreira , Machado Renato Assis , Furtado Paulo Germano Cavalcante , de Oliveira Lindalva Alves , de Aquino Sibele Nascimento , Martelli‐Junior Hercilio , de Almeida Reis Silvia Regina , Moreira Helenara Salvati Bertolossi , Persuhn Darlene Camati
Published: March 2015

Background

The MTHFR rs1801131A>C and rs1801133C>T variants have been analyzed as putative genetic risk factors for oral clefts within various populations worldwide.

Methods

To test the role of these polymorphisms in nonsyndromic cleft lip with or without cleft palate (NSCL/P) in the Brazilian population, we conducted a study combining a Family‐Based Association Test (transmission disequilibrium test) and a structured association analysis (case–control study) based on the individual ancestry proportions. The rs1801131 and rs1801133 were initially analyzed in 197 case‐parent trios by transmission disequilibrium test, and polymorphisms showing significant association with NSCL/P were subsequently studied in independent sample composed of 318 isolated samples of NSCL/P and 598 healthy controls in a case–control approach. Genomic ancestry was characterized by a set of 40 biallelic short insertion/deletion markers.

Results

A strong overtransmission of the T allele of rs1801133 was observed in case‐parent trios of NSCL/P (p = 0.002), but no preferential parent‐of‐origin transmission was detected. No association of rs1801131 polymorphism with NSCL/P was observed. The structured case–control analysis supported that the T allele was significantly more frequent in the NSCL/P group (odds ratio: 1.37; 95% CI: 1.12–1.69; p = 0.002) than in the control group. Both polymorphisms were in linkage disequilibrium (D′ = 0.94 and r2 = 0.79), and haplotype‐transmission disequilibrium test for allelic combination of rs1801131 and rs1801133 showed a significant overtransmission of haplotype A‐T to the affected NSCL/P offspring (p = 0.001).

Conclusion

Our findings provide evidences for the involvement of rs1801133 in the development of NSCL/P in the Brazilian population. Birth Defects Research (Part A) 103:292–298, 2015. © 2015 Wiley Periodicals, Inc.
Plasma folate levels in early to mid pregnancy after a nation‐wide folic acid supplementation program in areas with high and low prevalence of neural tube defects in china
Authors: Liu Jufen , Gao Lili , Zhang Yali , Jin Lei , Li Zhiwen , Zhang Le , Meng Qinqin , Ye Rongwei , Wang Linlin , Ren Aiguo
Published: March 2015

BACKGROUND

Folic acid supplementation is recommended for all women of child‐bearing age to prevent neural tube defects (NTDs). A nation‐wide folic acid supplementation program was implemented in rural areas of China since 2009; however, changes in plasma folate levels in pregnant women were unknown.

METHODS

A cross‐sectional survey was conducted in 2011 to 2012, with 1736 pregnant women enrolled, and results were compared with a previous survey in 2002 to 2004. A microbiological method was used to determine plasma folate levels. Preprogram and postprogram median plasma folate concentrations were compared while stratified by prevalence of NTDs and residence.

RESULTS

In the high NTD prevalence population, plasma folate concentration increased to 33.4 (18.7, 58.4) nmol/L in the postprogram sample, which is 2.9 times of the preprogram. In the low NTD prevalence population, plasma folate increased to 67.9 (44.5, 101.9) nmol/L, which is 1.9 times of the preprogram. Gaps remained in plasma folate levels with respect to prevalence of NTDs and residence. Folic acid supplementation has a strong impact on plasma folate concentrations. Earlier supplementation (before the last menstrual period), increased supplementation frequency and more total days of supplementation were associated with a higher plasma folate concentration as demonstrated in both the high‐ and low‐prevalence populations.

CONCLUSION

Plasma folate levels among pregnant Chinese women increased dramatically after the nation‐wide folic acid supplementation program in both rural and urban areas, and in populations of high and low NTD prevalence. The nation‐wide program should have a component to ensure that supplementation begins before pregnancy. Birth Defects Research (Part A) 103:501–508, 2015. © 2015 Wiley Periodicals, Inc.
TMS‐induced motor evoked potentials in Wilson's disease: A systematic literature review
Authors: Bembenek Jan P , Kurczych Katarzyna , Członkowska Anna
Published: March 2015

Wilson's disease (WD) is a metabolic brain disease resulting from improper copper metabolism. Although pyramidal symptoms are rarely observed, subclinical injury is highly possible as copper accumulates in all brain structures. The usefulness of motor evoked potentials (MEPs) in pyramidal tracts damage evaluation still appears to be somehow equivocal. We searched for original papers assessing the value of transcranial magnetic stimulation elicited MEPs with respect to motor function of upper and lower extremity in WD. We searched PubMed for original papers evaluating use of MEPs in WD using key words: “motor evoked potentials Wilson's disease” and “transcranial magnetic stimulation Wilson's disease.” We found six articles using the above key words. One additional article and one case report were found while viewing the references lists. Therefore, we included eight studies. Number of patients in studies was low and their clinical characteristic was variable. There were also differences in methodology. Abnormal MEPs were confirmed in 20–70% of study participants. MEPs were not recorded in 7.6–66.7% of patients. Four studies reported significantly increased cortical excitability (up to 70% of patients). Prolonged central motor conduction time was observed in four studies (30–100% of patients). One study reported absent or prolonged central motor latency in 66.7% of patients. Although MEPs may be abnormal in WD, this has not been thoroughly assessed. Hence, further studies are indispensable to evaluate MEPs' usefulness in assessing pyramidal tract damage in WD. Bioelectromagnetics. 36:255–266, 2015. © 2015 Wiley Periodicals, Inc.
Femoral perfusion after pulsed electromagnetic field stimulation in a steroid‐induced osteonecrosis model
Authors: Ikegami Akira , Ueshima Keiichiro , Saito Masazumi , Ikoma Kazuya , Fujioka Mikihiro , Hayashi Shigeki , Ishida Masashi , Fujiwara Hiroyoshi , Mazda Osam , Kubo Toshikazu
Published: March 2015

This study was designed to evaluate femoral perfusion after pulsed electromagnetic field (PEMF) stimulation in a steroid‐induced osteonecrosis rabbit model by dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI). Steroid‐induced osteonecrosis was produced by single intramuscular injection of methylprednisolone in 15 rabbits. Eight rabbits underwent PEMF stimulation (PEMF group) and seven did not (control group). DCE‐MRI was performed before PEMF stimulation, immediately before steroid administration, and 1, 5, 10, and 14 days after steroid administration. Regions of interest were set in the bilateral proximal femora. Enhancement ratio (ER), initial slope (IS), and area under the curve (AUC) were analyzed. ER, IS, and AUC in the control group significantly decreased after steroid administration compared with before administration (P < 0.05). In PEMF group, IS significantly decreased; however, ER and AUC showed no significant differences after steroid administration compared with before. ER and IS in PEMF group were higher than in control group until 10th day, and AUC was higher until 5th day after steroid administration (P < 0.05). PEMF stimulation restrains the decrease in blood flow after steroid administration. Bioelectromagnetics. 36:349–357, 2015. © 2015 Wiley Periodicals, Inc.
Circadian gene expression and extremely low‐frequency magnetic fields: An in vitro study
Authors: Manzella Nicola , Bracci Massimo , Ciarapica Veronica , Staffolani Sara , Strafella Elisabetta , Rapisarda Venerando , Valentino Matteo , Amati Monica , Copertaro Alfredo , Santarelli Lory
Published: March 2015

It is well known that circadian clocks are mainly regulated by light targeting signaling pathways in the hypothalamic suprachiasmatic nucleus. However, an entrainment mediated by non‐photic sensory stimuli was also suggested for peripheral clocks. Exposure to extremely low frequency (ELF) electromagnetic fields might affect circadian rhythmicity. The goal of this research was to investigate effects of ELF magnetic fields (ELF‐MF) on circadian clock genes in a human fibroblast cell line. We found that an ELF‐MF (0.1 mT, 50 Hz) exposure was capable of entraining expression of clock genes BMAL1, PER2, PER3, CRY1, and CRY2. Moreover, ELF‐MF treatment induced an alteration in circadian clock gene expression previously entrained by serum shock stimulation. These results support the hypothesis that ELF‐MF may be able to drive circadian physiologic processes by modulating peripheral clock gene expression. Bioelectromagnetics. 36:294–301, 2015. © 2015 Wiley Periodicals, Inc.
Point and interval estimation of baseline risk and treatment effect based on logistic model for observational studies
Authors: Wang Xiaoqin , Yin Li
Published: March 2015

In observational studies with dichotomous outcome of a population, researchers usually report treatment effect alone, although both baseline risk and treatment effect are needed to evaluate the significance of the treatment effect to the population. In this article, we study point and interval estimates including confidence region of baseline risk and treatment effect based on logistic model, where baseline risk is the risk of outcome of the population under control treatment while treatment effect is measured by the risk difference between outcomes of the population under active versus control treatments. Using approximate normal distribution of the maximum‐likelihood (ML) estimate of the model parameters, we obtain an approximate joint distribution of the ML estimate of the baseline risk and the treatment effect. Using the approximate joint distribution, we obtain point estimate and confidence region of the baseline risk and the treatment effect as well as point estimate and confidence interval of the treatment effect when the ML estimate of the baseline risk falls into specified range. These interval estimates reflect nonnormality of the joint distribution of the ML estimate of the baseline risk and the treatment effect. The method can be easily implemented by using any software that generates normal distribution. The method can also be used to obtain point and interval estimates of baseline risk and any other measure of treatment effect such as risk ratio and the number needed to treat. The method can also be extended from logistic model to other models such as log‐linear model.
Analyzing paired diagnostic studies by estimating the expected benefit
Authors: Gerke Oke , Høilund‐Carlsen Poul Flemming , Vach Werner
Published: March 2015

When the efficacy of a new medical drug is compared against that of an established competitor in a randomized controlled trial, the difference in patient‐relevant outcomes, such as mortality, is usually measured directly. In diagnostic research, however, the impact of diagnostic procedures is of an indirect nature as test results do influence downstream clinical decisions, but test performance (as characterized by sensitivity, specificity, and the predictive values of a procedure) is, at best, only a surrogate endpoint for patient outcome and does not necessarily translate into it. Not many randomized controlled trials have been conducted so far in diagnostic research, and, hence, we need alternative approaches to close the gap between test characteristics and patient outcomes. Several informal approaches have been suggested in order to close this gap, and decision modeling has been advocated as a means of obtaining formal approaches. Recently, the expected benefit has been proposed as a quantity that allows a simple formal approach, and we take up this suggestion in this paper. We regard the expected benefit as an estimation problem and consider two approaches to statistical inference. Moreover, using data from a previously published study, we illustrate the possible insights to be gained from the application of formal inference techniques to determine the expected benefit.
Mechanoluminescence, thermoluminescence, photoluminescence studies on Ca3Y2Si3O12:RE3+ (RE3+ = Dy3+and Eu3+) phosphors
Authors: Kadukar Monali R. , Yawalkar P. W. , Choithrani Renu , Dhoble S. J.
Published: March 2015

Dy3+ and Eu3+ activated Ca3Y2Si3O12 phosphors were synthesized by the solid‐state synthesis method. The phosphors were characterized by X‐ray diffraction (XRD), mechanoluminescence (ML), thermoluminescence (TL) and photoluminescence (PL) to determine structure and luminescence. For ML glow curves, only one peak was observed, as only one type of luminescence centre was formed during irradiation. The Ca3Y2Si3O12:Dy3+ TL glow curve showed a single peak at 151.55°C and the Ca3Y2Si3O12:Eu3+ TL glow curve peaked at 323°C with a small peak at 192°C, indicating that two types of traps were activated. The trapping parameters for both the samples were calculated using Chen's peak shape method. Dy3+‐activated Ca3Y2Si3O12 showed emission at 482 and 574 nm when excited by a 351 nm excitation wavelength, whereas the Eu3+‐activated Ca3Y2Si3O12 phosphor PL emission spectra showed emission peaks at 613 nm, 591 nm, 580 nm when excited at 395 nm wavelength. When excited at 466 nm, prominent emission peaks were observed at their respective positions with very slight shifts. Copyright © 2015 John Wiley & Sons, Ltd.
Transforming growth factor type‐β inhibits Mas receptor expression in fibroblasts but not in myoblasts or differentiated myotubes; Relevance to fibrosis associated to muscular dystrophies
Authors: Cofre Catalina , Acuña María José , Contreras Osvaldo , Morales María Gabriela , Riquelme Cecilia , Cabello‐Verrugio Claudio , Brandan Enrique
Published: March 2015

Duchenne muscular dystrophy is a genetic disorder characterized by myofiber degeneration, muscle weakness, and increased fibrosis. Transforming growth factor type‐β (TGF‐β), a central mediator of fibrosis, is upregulated in fibrotic diseases. Angiotensin‐(1–7) [Ang‐(1–7)] is a peptide with actions that oppose those of angiotensin‐II (Ang II). Ang‐(1–7) effects are mediated by the Mas receptor. Treatment with Ang‐(1–7) produce positive effects in the mdx mouse, normalizing skeletal muscle architecture, decreasing local fibrosis, and fibroblasts, and improving muscle function. Mdx mice deficient for the Mas receptor showed the opposite effects. To identify the cell type(s) responsible for Mas receptor expression, and to characterize whether profibrotic effectors had any effect on its expression, we determined the effect of profibrotic agents on Mas expression. TGF‐β, but not connective tissue growth factor or Ang‐II, reduced the expression of Mas receptor in fibroblasts isolated from skeletal muscle cells and fibroblasts from two established cell lines. In contrast, no effects were observed in myoblasts and differentiated myotubes. This inhibition was mediated by the Smad‐dependent (canonical) and the PI3K and MEK1/2 (noncanonical) TGF‐β signaling pathways. When both canonical and noncanonical inhibitors of the TGF‐β‐dependent pathways were added together, the inhibitory effect of TGF‐β on Mas expression was lost. The decrease in Mas receptor induced by TGF‐β in fibroblasts reduced the Ang‐(1–7) mediated stimulation of phosphorylation of AKT pathway proteins. These results suggest that reduction of Mas receptor in fibroblasts, by TGF‐β, could increase the fibrotic phenotype observed in dystrophic skeletal muscle decreasing the beneficial effect of Ang‐(1–7). © 2015 BioFactors, 41(2):111–120, 2015
Divalent cation‐aided identification of physico‐chemical properties of metal ions that stabilize RNA g‐quadruplexes
Authors: Balaratnam Sumirtha , Basu Soumitra
Published: March 2015

DNA and RNA sequences rich in guanosines (G) can form a four‐stranded secondary structure known as a G‐quadruplex (GQ), which plays a role in regulation of gene expression at the transcription and translation level. Both DNA and RNA GQs typically use the monovalent K+ ion for stabilization of the structures. However, the fundamental reasons for K+ acting as the most stabilizing metal ion for RNA GQs are not known. To identify the properties of a metal ion that stabilizes an RNA GQ we investigated the effect of alkaline earth metal cations and a set of divalent transition metal ions on two previously identified highly stable RNA GQs. Our results based upon circular dichroism and RNase T1 structure mapping data reveal that the RNA GQs are destabilized in the presence of the tested divalent metal cations. The destabilizing effect of a divalent metal cation is reversible upon increasing K+ concentration. Results show that ionic radius, hydration energy, and binding strength towards the hard ligand (guanine O6) are important factors that determine a metal ion's ability to stabilize an RNA GQ. Additionally, the tested set of divalent metal cations incongruously affects RNA and DNA GQs. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 376–386, 2015.
crystal structure analyses of azasulfuryltripeptides reveal potential for γ‐turn mimicry†
Authors: Turcotte Stéphane , Lubell William D.
Published: March 2015

Azasulfurylpeptides feature an amino acid residue in which the CαH and the carbonyl are replaced respectively by a nitrogen atom and a sulfonyl group. Insight into the conformational preferences of azasulfurylpeptides containing an azasulfurylglycine (AsG) residue has been pursued using X‐ray analysis in the solid state. Crystals of N‐(Boc)‐Pro‐AsG‐Val‐OMe (10) and N‐(Cbz)‐Ala‐AsG‐D‐Phe‐Ot‐Bu (11) showed tetrahedral geometries about the sulfur atom with the ω torsion angle preferring a staggered conformation. Furthermore, the ϕ and ψ torsion angles of the central azasulfuryl residue were respectively within close proximity to those of ideal inverse and classical γ‐turns. In the crystal lattice, azasulfurylpeptide 11 engaged in intermolecular hydrogen bonds between the sulfonyl oxygen and hydrazide hydrogen in an antiparallel orientation. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 622–628, 2015.
Molecular weight characterization of high molecular weight dextran with multiangle light scattering in on‐line and off‐line mode
Authors: Wang Jinfeng , Wang Jing
Published: March 2015

This work reports the molecular weight (MW) analysis of high MW dextran using multiangle light scattering (MALS) in both chromatography and automated batch measurement mode. The results show that the chromatographic columns alter the high MW native dextran and cause underestimation of the MW as a consequence. Alternatively, a batch MALS measurement (without columns) provides more accurate MW values. The batch MALS measurement was automated with the incorporation of an automatic sample dilution and injection device. This automation reduces the sample preparation time and minimizes concentration errors introduced by manual sample dilution. To the best of our knowledge, this is the first study using an automated batch MALS in the analysis of high MW dextran. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 387–392, 2015.
Kinetics of peptide folding in lipid membranes
Authors: Oh Kwang‐Im , Smith‐Dupont Kathryn B. , Markiewicz Beatrice N. , Gai Feng
Published: March 2015

Despite our extensive understanding of water‐soluble protein folding kinetics, much less is known about the folding dynamics and mechanisms of membrane proteins. However, recent studies have shown that for relatively simple systems, such as peptides that form a transmembrane α‐helix, helical dimer, or helix‐turn‐helix, it is possible to assess the kinetics of several important steps, including peptide binding to the membrane from aqueous solution, peptide folding on the membrane surface, helix insertion into the membrane, and helix‐helix association inside the membrane. Herein, we provide a brief review of these studies and also suggest new initiation and probing methods that could lead to improved temporal and structural resolution in future experiments. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 281–290, 2015.
Site‐selective modification of peptides: From “customizable units” to novel α‐aryl and α‐alkyl glycine derivatives, and components of branched peptides
Authors: Romero‐Estudillo Iván , Saavedra Carlos , Boto Alicia , Álvarez Eleuterio
Published: March 2015

The creation of peptide libraries by site‐selective modification of a few peptide substrates would increase the efficiency of discovery processes, but still is a real synthetic challenge. The site‐selective modification of small peptides at serine or threonine residues, by using a short scission–addition procedure, allows the preparation of peptides with unnatural α‐aryl glycines. In a similar way, the scission of hydroxyproline residues is the key step in the production of optically pure α‐alkyl glycines which are precursors or components of branched peptides. With these versatile processes, a single peptide can be transformed into a variety of peptide derivatives. The process takes place under mild conditions, and good global yields are obtained. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 650–662, 2015.