bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structurally diverse and readily tunable photocrosslinked chondroitin sulfate based copolymers
Authors: Khanlari Anahita , Suekama Tiffany C. , Detamore Michael S. , Gehrke Stevin H. 
Published: May 2015

ABSTRACTOur group has previously reported on successful biofunctionalization of poly(ethylene glycol diacrylate) (PEGDA) gels using chondroitin sulfate (CS) and improving moduli of methacrylated‐CS (MCS) gels using short PEGDA comonomers. Here, we focused on understanding the composition‐property relationship of MCS‐PEGDA copolymers. By changing concentration, composition, and medium's ionic strength the gels were modified to show a diverse range of properties. Photopolymerized copolymers with >4:1 ratio of one component had compressive moduli of up to 24 times higher and up to 17 times lower swelling degree (q) than those of MCS alone. The increased moduli and lowered q were consistent with the hypothesis that PEGDA improves kinetic chain growth by overcoming the steric hindrances of the macromer. The swelling and moduli of the gels were tuned by changing the ratio of the comonomers. The swelling and moduli of the gels were lowered with presence of salt in solution while the fracture strain increased. These changes were hypothesized to be the result of transition of CS chain conformation from highly extended and non‐Gaussian to less extended and Gaussian distribution. The complete understanding of MCS‐PEGDA composition–property relationship provides a general strategy to tune the moduli or q of polysaccharide‐based hydrogels while avoiding undesirable phase separation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1070–1079
Illness representations and psychological distress in Indian patients with cancer: does being aware of one's cancer diagnosis make a difference?
Authors: Chittem Mahati , Norman Paul , Harris Peter R. 
Published: May 2015

AbstractBackgroundThis study applied the Common Sense Model of illness representations to understand the psychological reactions of Indian patients with cancer who report being aware or unaware of their cancer diagnosis.MethodsAdult Indian patients with cancer (N = 329) were asked about their understanding of their illness (to assess awareness of a cancer diagnosis), and then completed the Brief Illness Perception Questionnaire and the Hospital Anxiety Depression Scale.ResultsPatients who reported being unaware of their cancer diagnosis (54.1%) experienced higher levels of anxiety and depression. After controlling for awareness, education, income, cancer symptoms, and cancer stage, illness perceptions accounted for significant amounts of variance in anxiety (∆R2 = 0.42) and depression (∆R2 = 0.33). Illness coherence mediated the relationship between awareness of a cancer diagnosis and anxiety. Moderated regression analyses indicated that several relationships between illness perceptions and anxiety/depression were stronger among patients who reported being unaware of their cancer diagnosis.ConclusionsThe Common Sense Model provides a useful framework for explaining the psychological reactions of Indian patients with cancer to their illness, particularly for those who report being unaware of their cancer diagnosis. Copyright © 2015 John Wiley & Sons, Ltd.
Molecular methods (digital PCR and real‐time PCR) for the quantification of low copy DNA of Phytophthora nicotianae in environmental samples
Authors: Blaya Josefa , Lloret Eva , Santísima‐Trinidad Ana B , Ros Margarita , Pascual Jose A 
Published: May 2015

AbstractBACKGROUNDCurrently, real‐time polymerase chain reaction (qPCR) is the technique most often used to quantify pathogen presence. Digital PCR (dPCR) is a new technique with the potential to have a substantial impact on plant pathology research owing to its reproducibility, sensitivity and low susceptibility to inhibitors. In this study, we evaluated the feasibility of using dPCR and qPCR to quantify Phytophthora nicotianae in several background matrices, including host tissues (stems and roots) and soil samples.RESULTSIn spite of the low dynamic range of dPCR (3 logs compared with 7 logs for qPCR), this technique proved to have very high precision applicable at very low copy numbers. The dPCR was able to detect accurately the pathogen in all type of samples in a broad concentration range. Moreover, dPCR seems to be less susceptible to inhibitors than qPCR in plant samples. Linear regression analysis showed a high correlation between the results obtained with the two techniques in soil, stem and root samples, with R2 = 0.873, 0.999 and 0.995 respectively.CONCLUSIONSThese results suggest that dPCR is a promising alternative for quantifying soil‐borne pathogens in environmental samples, even in early stages of the disease. © 2015 Society of Chemical Industry
Metal‐Dependent Topologies and Water Aggregations in Copper and Nickel Carboxycinnamate Coordination Polymers with a Long‐Spanning Dipyridylamide Ligand
Authors: Rogers Ciana M. , Glatz Erika J. , LaDuca Robert L. 
Published: May 2015

AbstractHydrothermal reaction of the requisite metal nitrate, carboxycinnamic acid (H2cca), and the long‐spanning dipyridylamide bis(4‐pyridylformyl)piperazine (4‐bpfp) generate crystalline coordination polymers whose topology depends critically on the metal coordination geometric preference. These two new phases were structurally characterized by single‐crystal X‐ray diffraction. {[Cu(cca)(4‐bpfp)]·2.5H2O}n (1) manifests a non‐interpenetrated 6‐connected pcu net based on chain motifs featuring carboxylate‐bridged {Cu2(OCO)2} dinuclear units, with embedded D(5) water molecule chains. {[Ni(cca)(4‐bpfp)(H2O)2]·3H2O}n (2) displays an acentric twofold interpenetrated 4‐connected 66 dia network topology with entrapped R(4)A(1) water molecule rings. Variable temperature magnetic studies performed on 1 revealed very weak antiferromagnetic coupling within its dinuclear units. Thermal properties of these two new materials are also discussed.
Hydrothermal Studies in the System Hg/Se/Te/O: The First TeIV/SeVI Oxocompounds Hg3SeTe2O10 and Hg3SeTe4O14, and the Mixed‐valent Hg5Se2O8
Authors: Weil Matthias , Shirkanlou Mahdi 
Published: May 2015

AbstractReactions of HgII‐, TeIV‐, and SeVI‐containing starting materials under moderate hydrothermal conditions (230 °C, one week) resulted in the formation of the mercuric oxotellurate(IV)/oxoselenate(VI) phases Hg3SeTe2O10 and Hg3SeTe4O14. The mixed‐valent phase Hg5Se2O8 containing mercury in oxidation states +I and +II as well as selenium in oxidation states +IV and +VI also formed under these conditions. The crystal structures of the three compounds were determined from single‐crystal X‐ray data. All structures contain building blocks characteristic for HgI or HgII cations and for oxochalcogenate anions of SeIV, SeVI, or TeIV. Whereas the oxoselenate(VI) and oxotellurate(IV) anions are isolated in the structure of Hg3SeTe2O10, the higher TeO2 content in the structure of Hg3SeTe4O14 leads to a condensation of the corresponding anions. The crystal structure of Hg5Se2O8 is described in terms of oxo‐centered [OHg4] tetrahedra.
Mitochondrial transcript maturation and its disorders
Authors: Van Haute Lindsey , Pearce Sarah F. , Powell Christopher A. , D'Souza Aaron R. , Nicholls Thomas J. , Minczuk Michal 
Published: May 2015

AbstractMitochondrial respiratory chain deficiencies exhibit a wide spectrum of clinical presentations owing to defective mitochondrial energy production through oxidative phosphorylation. These defects can be caused by either mutations in the mitochondrial DNA (mtDNA) or mutations in nuclear genes coding for mitochondrially‐targeted proteins. The underlying pathomechanisms can affect numerous pathways involved in mitochondrial biology including expression of mtDNA‐encoded genes. Expression of the mitochondrial genes is extensively regulated at the post‐transcriptional stage and entails nucleolytic cleavage of precursor RNAs, RNA nucleotide modifications, RNA polyadenylation, RNA quality and stability control. These processes ensure proper mitochondrial RNA (mtRNA) function, and are regulated by dedicated, nuclear‐encoded enzymes. Recent growing evidence suggests that mutations in these nuclear genes, leading to incorrect maturation of RNAs, are a cause of human mitochondrial disease. Additionally, mutations in mtDNA‐encoded genes may also affect RNA maturation and are frequently associated with human disease. We review the current knowledge on a subset of nuclear‐encoded genes coding for proteins involved in mitochondrial RNA maturation, for which genetic variants impacting upon mitochondrial pathophysiology have been reported. Also, primary pathological mtDNA mutations with recognised effects upon RNA processing are described.
A STOCHASTIC FRONTIER ANALYSIS TO EXAMINE RESEARCH PRIORITIES FOR GENETICALLY ENGINEERED PEANUTS
Authors: AFFUSO ERMANNO , HITE DIANE , WILSON NORBERT W.L. 
Published: May 2015

AbstractPesticide applications are essential for peanut production to control insects, weeds, and other plant pathogens and for a profitable operation. We use a stochastic frontier analysis/primal system approach to test the hypothesis of the overuse of fungicides among peanut farmers. With nationally representative data available from the Agricultural and Resource Management Survey, we find evidence that U.S. peanut growers used excessive amounts of fungicides to prevent fungal infections. If those farmers adopt a new cultivar resistant to fungal pathogens, they could reduce the total cost of chemicals up to 36.2%. The reduction in fungicide use would have spillover environmental benefits.
Pharmacokinetics of intravenous sildenafil in children with palliated single ventricle heart defects: effect of elevated hepatic pressures
Authors: Hill Kevin D. , Sampson Mario R. , Li Jennifer S. , Tunks Robert D. , Schulman Scott R. , Cohen-Wolkowiez Michael 
Published: May 2015

AbstractAimsSildenafil is frequently prescribed to children with single ventricle heart defects. These children have unique hepatic physiology with elevated hepatic pressures, which may alter drug pharmacokinetics. We sought to determine the impact of hepatic pressure on sildenafil pharmacokinetics in children with single ventricle heart defects.MethodsA population pharmacokinetic model was developed using data from 20 single ventricle children receiving single-dose intravenous sildenafil during cardiac catheterisation. Non-linear mixed effect modelling was used for model development, and covariate effects were evaluated based on estimated precision and clinical significance.ResultsThe analysis included a median (range) of 4 (2–5) pharmacokinetic samples per child. The final structural model was a two-compartment model for sildenafil with a one-compartment model for des-methyl-sildenafil (active metabolite), with assumed 100% sildenafil to des-methyl-sildenafil conversion. Sildenafil clearance was unaffected by hepatic pressure (clearance=0.62 L/hour/kg); however, clearance of des-methyl-sildenafil (1.94×(hepatic pressure/9)−1.33 L/hour/kg) was predicted to decrease ~7-fold as hepatic pressure increased from 4 to 18 mmHg. Predicted drug exposure was increased by ~1.5-fold in subjects with hepatic pressures ⩾10 versus <10 mmHg (median area under the curve=533 versus 792 µg*h/L).DiscussionElevated hepatic pressure delays clearance of the sildenafil metabolite – des-methyl-sildenafil – and increases drug exposure. We speculate that this results from impaired biliary clearance. Hepatic pressure should be considered when prescribing sildenafil to children. These data demonstrate the importance of pharmacokinetic assessments in patients with unique cardiovascular physiology that may affect drug metabolism.
Acetylation of Beclin 1 inhibits autophagosome maturation and promotes tumour growth
Authors: Sun Ting , Li Xuan , Zhang Peng , Chen Wen-Dan , Zhang Hai-liang , Li Dan-Dan , Deng Rong , Qian Xiao-Jun , Jiao Lin , Ji Jiao , Li Yun-Tian , Wu Rui-Yan , Yu Yan , Feng Gong-Kan , Zhu Xiao-Feng 
Published: May 2015

AbstractBeclin 1, a protein essential for autophagy, regulates autophagy by interacting with Vps34 and other cofactors to form the Beclin 1 complex. Modifications of Beclin 1 may lead to the induction, inhibition or fine-tuning of the autophagic response under a variety of conditions. Here we show that Beclin 1 is acetylated by p300 and deacetylated by SIRT1 at lysine residues 430 and 437. In addition, the phosphorylation of Beclin 1 at S409 by CK1 is required for the subsequent p300 binding and Beclin 1 acetylation. Beclin 1 acetylation inhibits autophagosome maturation and endocytic trafficking by promoting the recruitment of Rubicon. In tumour xenografts, the expression of 2KR mutant Beclin 1 (substitution of K430 and K437 to arginines) leads to enhanced autophagosome maturation and tumour growth suppression. Therefore, our study identifies an acetylation-dependent regulatory mechanism governing Beclin 1 function in autophagosome maturation and tumour growth.
Formation of As-As Interlayer Bonding in the collapsed tetragonal phase of NaFe2As2 under pressure
Authors: Stavrou Elissaios , Chen Xiao-Jia , Oganov Artem R. , Wang A. F. , Yan Y. J. , Luo X. G. , Chen X. H. , Goncharov Alexander F. 
Published: May 2015

AbstractNaFe2As2 is investigated experimentally using powder x-ray diffraction and Raman spectroscopy at pressures up to 23 GPa at room temperature and using ab-initio calculations. The results reveal a pressure-induced structural modification at 4 GPa from the starting tetragonal to a collapsed tetragonal phase. We determined the changes in interatomic distances under pressure that allowed us to connect the structural changes and superconductivity. The transition is related to the formation of interlayer As-As bonds at the expense of weakening of Fe-As bonds in agreement with recent theoretical predictions.
Dzyaloshinskii-Moriya Interaction and Spiral Order in Spin-orbit Coupled Optical Lattices
Authors: Gong Ming , Qian Yinyin , Yan Mi , Scarola V. W. , Zhang Chuanwei 
Published: May 2015

AbstractWe show that the recent experimental realization of spin-orbit coupling in ultracold atomic gases can be used to study different types of spin spiral order and resulting multiferroic effects. Spin-orbit coupling in optical lattices can give rise to the Dzyaloshinskii-Moriya (DM) spin interaction which is essential for spin spiral order. By taking into account spin-orbit coupling and an external Zeeman field, we derive an effective spin model in the Mott insulator regime at half filling and demonstrate that the DM interaction in optical lattices can be made extremely strong with realistic experimental parameters. The rich finite temperature phase diagrams of the effective spin models for fermions and bosons are obtained via classical Monte Carlo simulations.
Dynamic near-field optical interaction between oscillating nanomechanical structures
Authors: Ahn Phillip , Chen Xiang , Zhang Zhen , Ford Matthew , Rosenmann Daniel , Jung II Woong , Sun Cheng , Balogun Oluwaseyi 
Published: May 2015

AbstractNear-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45 pm/Hz1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20 nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129 MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.
Information processing via physical soft body
Authors: Nakajima Kohei , Hauser Helmut , Li Tao , Pfeifer Rolf 
Published: May 2015

AbstractSoft machines have recently gained prominence due to their inherent softness and the resulting safety and resilience in applications. However, these machines also have disadvantages, as they respond with complex body dynamics when stimulated. These dynamics exhibit a variety of properties, including nonlinearity, memory and potentially infinitely many degrees of freedom, which are often difficult to control. Here, we demonstrate that these seemingly undesirable properties can in fact be assets that can be exploited for real-time computation. Using body dynamics generated from a soft silicone arm, we show that they can be employed to emulate desired nonlinear dynamical systems. First, by using benchmark tasks, we demonstrate that the nonlinearity and memory within the body dynamics can increase the computational performance. Second, we characterize our system’s computational capability by comparing its task performance with a standard machine learning technique and identify its range of validity and limitation. Our results suggest that soft bodies are not only impressive in their deformability and flexibility but can also be potentially used as computational resources on top and for free.
Cell Size Modulates Oscillation, Positioning and Length of Mitotic Spindles
Authors: Jiang Hongyuan 
Published: May 2015

AbstractMitotic spindle is the main subcellular structure that accomplishes the chromosome segregation between daughter cells during cell division. However, how mitotic spindles sense and control their size, position and movement inside the cell still remains unclear. In this paper, we focus on the size effects of mitotic spindles, i.e., how cell size controls various interesting phenomena in the metaphase, such as oscillation, positioning and size limit of mitotic spindles. We systematically studied the frequency doubling phenomenon during chromosome oscillation and found that cell size can regulate the period and amplitude of chromosome oscillation. We found that the relaxation time of the positioning process increases exponentially with cell size. We also showed that the stabler microtubule-kinetochore attachments alone can directly lead to an upper limit of spindle size. Our work not only explains the existing experimental observations, but also provides some interesting predictions that can be verified or rejected by further experiments.
Electronic Band Structure and Sub-band-gap Absorption of Nitrogen Hyperdoped Silicon
Authors: Zhu Zhen , Shao Hezhu , Dong Xiao , Li Ning , Ning Bo-Yuan , Ning Xi-Jing , Zhao Li , Zhuang Jun 
Published: May 2015

AbstractWe investigated the atomic geometry, electronic band structure and optical absorption of nitrogen hyperdoped silicon based on first-principles calculations. The results show that all the paired nitrogen defects we studied do not introduce intermediate band, while most of single nitrogen defects can introduce intermediate band in the gap. Considering the stability of the single defects and the rapid resolidification following the laser melting process in our sample preparation method, we conclude that the substitutional nitrogen defect, whose fraction was tiny and could be neglected before, should have considerable fraction in the hyperdoped silicon and results in the visible sub-band-gap absorption as observed in the experiment. Furthermore, our calculations show that the substitutional nitrogen defect has good stability, which could be one of the reasons why the sub-band-gap absorptance remains almost unchanged after annealing.
Eye closure enhances dark night perceptions
Authors: Brodoehl Stefan , Klingner Carsten M. , Witte Otto W. 
Published: May 2015

AbstractWe often close our eyes when we explore objects with our fingers to reduce the dominance of the visual system over our other senses. Here we show that eye closure, even in complete darkness, results in improved somatosensory perception due to a switch from visual predominance towards a somatosensory processing mode. Using a tactile discrimination task and functional neuroimaging (fMRI) data were acquired from healthy subjects with their eyes opened and closed in two environments: under ambient light and in complete darkness. Under both conditions the perception threshold decreased when subjects closed their eyes and their fingers became more sensitive. In complete darkness, eye closure significantly increased occipital blood-oxygen-level-dependent (BOLD) activity in the somatosensory and secondary visual processing areas. This change in brain activity was associated with enhanced coupling between the sensory thalamus and somatosensory cortex; connectivity between the visual and somatosensory areas decreased. The present study demonstrates that eye closure improves somatosensory perception not merely due to the lack of visual signals; instead, the act of closing the eyes itself alters the processing mode in the brain: with eye closure the brain switches from thalamo-cortical networks with visual dominance to a non-visually dominated processing mode.
Effects of drug-resistant mutations on the dynamic properties of HIV-1 protease and inhibition by Amprenavir and Darunavir
Authors: Yu Yuqi , Wang Jinan , Shao Qiang , Shi Jiye , Zhu Weiliang 
Published: May 2015

AbstractMolecular dynamics simulations are performed to investigate the dynamic properties of wild-type HIV-1 protease and its two multi-drug-resistant variants (Flap + (L10I/G48V/I54V/V82A) and Act (V82T/I84V)) as well as their binding with APV and DRV inhibitors. The hydrophobic interactions between flap and 80 s (80’s) loop residues (mainly I50-I84’ and I50’-I84) play an important role in maintaining the closed conformation of HIV-1 protease. The double mutation in Act variant weakens the hydrophobic interactions, leading to the transition from closed to semi-open conformation of apo Act. APV or DRV binds with HIV-1 protease via both hydrophobic and hydrogen bonding interactions. The hydrophobic interactions from the inhibitor is aimed to the residues of I50 (I50’), I84 (I84’) and V82 (V82’) which create hydrophobic core clusters to further stabilize the closed conformation of flaps and the hydrogen bonding interactions are mainly focused with the active site of HIV-1 protease. The combined change in the two kinds of protease-inhibitor interactions is correlated with the observed resistance mutations. The present study sheds light on the microscopic mechanism underlying the mutation effects on the dynamics of HIV-1 protease and the inhibition by APV and DRV, providing useful information to the design of more potent and effective HIV-1 protease inhibitors.