bluuebunny/crossref_metadata_2025_split huggingface dataset:
Osteodifferentiation of mesenchymal stem cells on chitosan/hydroxyapatite composite films
Authors: Yang Julin , Liu Aiming , Han Yuanyuan , Li Qingning , Tian Jinhuan , Zhou Changren 
Published: April 2013

AbstractChitosan (Ch) is one of the most commonly used natural biomaterials. Osteodifferentiation of mesenchymal stem cells (MSCs) on Ch has drawn extensive interest. Hydroxyapatite (HA) is a component of skeleton and teeth with good biocompatibility. Combination with HA may be a good method to modify Ch to facilitate cellular behaviors and functions on it. In this study, Ch/HA film was prepared and characterized. Its potential to benefit cellular behaviors and osteodifferentiation of MSCs was evaluated. Resultantly, physical properties of composite Ch/HA, including water‐in‐air contact angle, tensile strength, elastic modulus, and breaking elongation were favorably modified. In cellular culture medium, Ch/HA films absorbed more Ca2+ than Ch films, and more HA crystalline growths on Ch/HA films. 3‐(4,5‐Dimethythiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide assay and morphological features showed better proliferation and adhesion of MSCs on Ch/HA films. Osteodifferentiation of MSCs on Ch/HA was promoted, indicated by modified transcription level of osteocalcin, osteopontin, collagen I, alkaline phosphatase (ALP), and induced ALP activity. These data suggest biocompatibility of Ch is modified after being blended with HA, which promotes osteodifferentiation of MSCs. This can be a promising approach to modify Ch for its applications in bone tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 1202–1209, 2014.
‐Relative Difference Sets and Their Representations
Authors: Zhou Yue 
Published: April 2013

AbstractWe show that every ‐relative difference set D in relative to can be represented by a polynomial , where is a permutation for each nonzero a. We call such an f a planar function on . The projective plane Π obtained from D in the way of M. J. Ganley and E. Spence (J Combin Theory Ser A, 19(2) (1975), 134–153) is coordinatized, and we obtain necessary and sufficient conditions of Π to be a presemifield plane. We also prove that a function f on with exactly two elements in its image set and is planar, if and only if, for any .
Rapid detection and quantitation of ganciclovir resistance in cytomegalovirus quasispecies
Authors: Ruiz‐Carrascoso Guillermo , Romero‐Gómez María Pilar , Plaza Diego , Mingorance Jesús 
Published: April 2013

AbstractHuman cytomegalovirus (HCMV) may cause severe or fatal disease among immunocompromised patients. The first line prophylaxis and systemic HCMV disease therapy is ganciclovir (GCV). The presence of GCV‐resistant virus has been linked to fatal HCMV disease. The implementation of rapid and sensitive techniques for the early detection and monitoring of GCV‐resistance may be helpful to support antiviral therapy management. A pyrosequencing assay for the detection and quantitation of the most frequent mutations conferring moderate‐ and high‐grade GCV resistance was implemented. The pyrosequencing achieved an analytical sensitivity for adequate interpretation of ≥103 copies/ml. The assay was validated with 18 whole blood samples taken over a 6‐month period from an umbilical cord blood recipient infected persistently with HCMV and allowed the detection and monitoring of the M460I and A594V GCV‐resistant mutations. The percentage of resistant quasispecies ranged from 7.9% to 55.2% for the M460I mutation and from 19.8% to 43% for the A594V mutation. Clearance of the M460I mutation occurred in parallel with a decrease in the HCMV viremia, while the A594V mutation persisted. The pyrosequencing method for detection of GCV is sensitive enough to be used directly on clinical samples for the early identification of resistance mutations and allows the quantitation of resistant and wild type virus quasispecies within hours. The quantitation of minor resistant variants is an important issue to understand their relationship with viral load modification, and potentially anticipate treatment adjustment. J. Med. Virol. 85:1250–1257, 2013. © 2013 Wiley Periodicals, Inc.
Polystyrene Brushes on Fully Deuterated Organic Nanoparticles by Surface‐Initiated Nitroxide‐Mediated Radical Polymerization
Authors: Mazurowski Markus , Sondergeld Katrin , Elbert Johannes , Kim Chang Jong , Li Junyu , Frielinghaus Henrich , Gallei Markus , Stühn Bernd , Rehahn Matthias 
Published: April 2013

AbstractThe synthesis of polystyrene (PS) brushes on fully deuterated PS nanoparticles by surface‐initiated nitroxide‐mediated radical polymerization (SI‐NMRP) is reported. Due to the high demand of deuterated monomers, an efficient deuteration procedure of suitable and readily available precursors is developed. SI‐NMRP of styrene is improved regarding reaction control, grafting density, and conversion. Insights into the scaling behavior and conformational features of surface‐attached PS chains on deuterated particles are investigated by using dynamic light scattering measurements, proving that polymer brushes are formed. The particles with surface‐attached initiator are shown to be uniform spherical core‐shell particles by small‐angle neutron scattering measurements.magnified image
Free‐Radical Polymerization of N‐Vinylimidazole and Quaternized Vinylimidazole in Aqueous Solution
Authors: Santanakrishnan Sandhya , Hutchinson Robin A. 
Published: April 2013

AbstractAqueous‐phase free‐radical batch polymerizations of N‐vinylimidazole (NVI) and quaternized N‐vinylimidazole (QVI) are conducted with varying initial monomer and initiator concentrations at 70 and 85 °C. The polymerization rate of NVI is very slow at the natural pH of 9 due to degradative radical addition to monomer. The rates are increased by lowering the pH, wherein the degradative addition to NVI monomer is partially (at pH 4) and completely (at pH 1) hindered, with the polymerization rate matching that of QVI at pH 1. The initial rates of polymerization for both NVI and QVI are independent of temperature. A kinetic model developed in Predici that includes the pH‐dependent side reactions can reasonably represent both QVI and NVI polymerization.magnified image
A method for noninvasive detection of fetal large deletions/duplications by low coverage massively parallel sequencing
Authors: Chen Shengpei , Lau Tze Kin , Zhang Chunlei , Xu Chenming , Xu Zhengfeng , Hu Ping , Xu Jian , Huang Hefeng , Pan Ling , Jiang Fuman , Chen Fang , Pan Xiaoyu , Xie Weiwei , Liu Ping , Li Xuchao , Zhang Lei , Li Songgang , Li Yingrui , Xu Xun , Wang Wei , Wang Jun , Jiang Hui , Zhang Xiuqing 
Published: April 2013

ABSTRACTObjectiveTo report the feasibility of fetal chromosomal deletion/duplication detection using a novel bioinformatic method of low coverage whole genome sequencing of maternal plasma.MethodA practical method Fetal Copy‐number Analysis through Maternal Plasma Sequencing (FCAPS), integrated with GC‐bias correction, binary segmentation algorithm and dynamic threshold strategy, was developed to detect fetal chromosomal deletions/duplications of >10 Mb by low coverage whole genome sequencing (about 0.08‐fold). The sensitivity/specificity of the resultant FCAPS algorithm in detecting deletions/duplications was firstly assessed in silico and then tested in 1311 maternal plasma samples from those with known G‐banding karyotyping results of the fetus.ResultsDeletions/duplications, ranged from 9.01 to 28.46 Mb, were suspected in four of the 1311 samples, of which three were consistent with the results of fetal karyotyping. In one case, the suspected abnormality was not confirmed by karyotyping, representing a false positive case. No false negative case was observed in the remaining 1307 low‐risk samples. The sensitivity and specificity for detection of >10‐Mb chromosomal deletions/duplications were100% and 99.92%, respectively.ConclusionOur study demonstrated FCAPS has the potential to detect fetal large deletions/duplications (>10 Mb) with low coverage maternal plasma DNA sequencing currently used for fetal aneuploidy detection. © 2013 John Wiley & Sons, Ltd.
Long‐term health and development of children diagnosed prenatally with a de novo apparently balanced chromosomal rearrangement
Authors: Sinnerbrink Ingrid B. , Sherwen Amanda , Meiser Bettina , Halliday Jane , Amor David J. , Waters Elizabeth , Rea Felicity , Evans Elizabeth , Rahman Belinda , Kirk Edwin P. 
Published: April 2013

ABSTRACTObjectiveThis study aimed to determine if liveborn children with prenatally detected de novo apparently balanced chromosome rearrangements (ABCR) have more long‐term health, developmental or behavioural concerns compared with children in a normal Australian population.MethodsThis was a retrospective ascertainment of all liveborn children with prenatally detected de novo ABCRs in two Australian states over a 10‐year period (1994–2003). Child health, development and behaviour were assessed by maternal report using standardised measures; educational ability and achievement were measured by direct child assessment. Data were compared with relevant population norms, and one sample t‐test performed to test for statistical differences.ResultsOf 39 eligible cases, 16 (41%) participated in the study. One child (6%) was born with a congenital anomaly, and two children (12.5%) reported a chronic health concern. Compared with population norms, no significant differences were observed with respect to intelligence, mental health, child development and educational ability; children had significantly higher scores indicative of better functioning on bodily pain, social–emotional behaviour and physical functioning. No child satisfied the criteria for having a special health care need.ConclusionChildren in this study with a prenatally detected de novo ABCR have similar long‐term health, developmental and behavioural outcomes compared with population norms. © 2013 John Wiley & Sons, Ltd.
δ13C and δ2H measurement of methane from ecological and geological sources by gas chromatography/combustion/pyrolysis isotope‐ratio mass spectrometry
Authors: Yarnes Chris 
Published: April 2013

RATIONALEThe carbon and hydrogen isotopes of methane are useful in differentiating biological (e.g. wetlands, ruminants, biomass burning) and geological methane sources (e.g. fossil fuels, gas hydrates), as well as quantifying pathways of methanotrophism. Continuous‐flow isotopic measurements of methane present a set of analytical challenges, including sample size restrictions and separation of CH4 from atmosphere, hydrocarbons, and CO2.METHODSSmall‐scale modifications were made to a commercial trace‐gas preconcentration and sampling unit (Thermo Scientific PreCon‐GasBench) for improved isotopic analysis of methane (δ13C/δ2H) across a range of gas concentrations.RESULTSThe long‐term reproducibility of δ13C‐CH4 values is less than ±0.2‰ (1σ). The limit‐of‐quantitation of δ13C‐CH4 values is less than 0.8 nmol, conveniently measurable within standard gas sampling vials. A reproducibility of better than ±4‰ (1σ) is regularly achieved for δ2H values from sample sizes greater than 2 nmol. The range of measurement, for both δ13C and δ2H values, is easily extended from ambient concentration (~1.7 ppm‐v) for preconcentrated samples to percent methane concentrations under subsampling.CONCLUSIONSThe automated measurement of δ13C‐CH4 and δ2H‐CH4 values, from ambient to percentage concentrations, is possible with minimal modifications to a commercial preconcentration/gas chromatography inlet. Sample matrix interferences (CO2, CnHy, air) are eliminated and simultaneous isotopic measurements of methane and CO2 and/or C1‐C4 light hydrocarbons are possible, while still retaining functionality for isotopic measurements of other gas species (e.g. CO2, N2, O2). Copyright © 2013 John Wiley & Sons, Ltd.
Quantification of the ionization probability during desorption/ionization of oligopeptides induced by neutral cluster impact
Authors: Lee B.‐J. , Baur M. , Gebhardt C. R. , Dürr M. 
Published: April 2013

RATIONALEDesorption‐and‐ionization induced by neutral cluster impact is a soft and matrix‐free method, which leads to the formation of free ions of oligopeptides and smaller proteins without fragmentation. As a prerequisite for its successful application in bioanalytics, especially with respect to sensitivity, the ionization efficiency, i.e., the ion‐to‐neutral ratio of the desorbing molecules, was determined.METHODSNeutral SO2 clusters of 103 to 104 molecules in size were seeded in a pulsed He beam and used to desorb and ionize oligopeptides by means of cluster surface impact. The samples were prepared by drop casting a well‐defined amount of substance on the substrate surface; the desorbing ions were identified by means of time‐of‐flight mass spectrometry. Furthermore, the ion current leaving the surface was determined for positive ions, which predominate in the investigated oligopeptides.RESULTSFor angiotensin II, bradykinin (1‐7), and adrenocorticotropic hormone (34‐39), the number of ions desorbed from the respective samples was compared with the amount of substance applied on the substrate. Assuming that all biomolecules were desorbed during the experiment, the ion‐to‐neutral ratio or ionization efficiency η was determined. For the tested molecules, values of η between 0.5% and 3% were observed; the substrate material and the total amount of substance applied were shown to have a minor effect on the results.CONCLUSIONSThe ion‐to‐neutral ratio in desorption/ionization of oligopeptides induced by neutral cluster impact was determined to be of the order of 10−3 to 10−2. The soft and matrix‐free nature of the method in combination with this value of η might be interesting for applications in bioanalytics. Copyright © 2013 John Wiley & Sons, Ltd.
Surgeons and Surgery from Ancient Persia (5,000 Years of Surgical History)
Authors: Zargaran Arman , Fazelzadeh Afsoon , Mohagheghzadeh Abdolali 
Published: April 2013

AbstractThe development of surgery is indebted to scientists and surgeons from various civilizations throughout history. The present study considers surgery in the ancient Persian civilization. It highlights aspects of the subject, such as findings of the first trephinated skulls in Iran; surgeons’ social class (kareto baēšaza in the Avestan language—dating back 3,000 years); surgical operations such as cesarean section and procedures to treat breast cancer; and the use of anesthetic compounds and surgical practice in the military. It is hoped that this catalogue of historical evidence of surgical practice in ancient Persian civilization will contribute to the history of surgery, as an important field in medical science.
Flow Behavior of Oleic Acid Liposomes in Sucrose Ester Glycolipid Oil‐in‐Water Emulsions
Authors: Chia Si Wai , Misran Misni 
Published: April 2013

AbstractLiposomes have been used widely as carriers for active ingredients in cosmetics because of their ability to encapsulate both hydrophilic and hydrophobic compounds. In this work, fatty acid liposomes were prepared and introduced into olive oil‐in‐water emulsions stabilized by C14–C18 sucrose ester mixtures at pH 8.5. Light microscopy images of the emulsions showed evidence of the coexistence of oleic acid liposomes with the emulsions. As the alkyl chain length of the sucrose ester increased, the average droplet size decreased, while the zeta potential became more negative. Further decrease in droplet size was observed when borate buffer was added to the aqueous phase. The free fatty acids in the sucrose esters and olive oil are neutralized in borate buffer; consequently, fatty acid salts were produced and served as co‐surfactants. The synergistic stabilization of emulsions by the mixture of sucrose esters and fatty acid salt resulted in higher stability, smaller droplet size, and lower polydispersity. The drastic increase in negative zeta potential was possibly due to the presence of free fatty acid salts in the emulsion systems. The flow curves at steady rate displayed five distinctive regions. The polydispersity of droplets enhanced the shear thickening effect at low shear rates and shear‐banding effect at middle shear rates. Formation of fatty acid salts as co‐surfactants caused the viscosities of the emulsions to increase by an order of magnitude. The presence of oleic acid liposome significantly reduced the viscosities of the emulsion by half an order of magnitude; this decreased viscosity helped enhance better spreadability.
Introducing an instrument to assess time orientation and time relation in adolescents
Authors: Mello Zena R. , Finan Laura J. , Worrell Frank C. 
Published: April 2013

ABSTRACTWe report on two studies that examine new instruments that assess time orientation and time relation in adolescents. These concepts refer to how individuals think about the past, the present, and the future, with time orientation defined as the emphasis one gives toward each time period and time relation defined as the degree one perceives that the time periods are related to one another. Study 1 showed that time orientation predicted academic achievement and self‐esteem and time relation predicted academic achievement and hope. Study 2, which included revised versions of the instruments, replicated most findings and demonstrated that both time orientation and time relation were related to engaging in risky behaviors. As hypothesized, in both studies, there were no gender differences in time orientation or time relation. These instruments provide a new way to assess how adolescents' perceive time and how this relates to their development and behavior.
Quasi-geostrophic shallow-water doubly-connected vortex equilibria and their stability
Authors: Płotka Hanna , Dritschel David G. 
Published: April 2013

AbstractWe examine the form, properties, stability and evolution of doubly-connected (two-vortex) relative equilibria in the single-layer $f$-plane quasi-geostrophic shallow-water model of geophysical fluid dynamics. Three parameters completely describe families of equilibria in this system: the ratio $\gamma = L/ {L}_{D} $ between the horizontal size of the vortices and the Rossby deformation length; the area ratio $\alpha $ of the smaller to the larger vortex; and the minimum distance $\delta $ between the two vortices. We vary $0\lt \gamma \leq 10$ and $0. 1\leq \alpha \leq 1. 0$, determining the boundary of stability $\delta = {\delta }_{c} (\gamma , \alpha )$. We also examine the nonlinear development of the instabilities and the transitions to other near-equilibrium configurations. Two modes of instability occur when $\delta \lt {\delta }_{c} $: a small-$\gamma $ asymmetric (wave 3) mode, which is absent for $\alpha \gtrsim 0. 6$; and a large-$\gamma $ mode. In general, major structural changes take place during the nonlinear evolution of the vortices, which near ${\delta }_{c} $ may be classified as follows: (i) vacillations about equilibrium for $\gamma \gtrsim 2. 5$; (ii) partial straining out, associated with the small-$\gamma $ mode, where either one or both of the vortices get smaller for $\gamma \lesssim 2. 5$ and $\alpha \lesssim 0. 6$; (iii) partial merger, occurring at the transition region between the two modes of instability, where one of the vortices gets bigger, and (iv) complete merger, associated with the large-$\gamma $ mode. We also find that although conservative inviscid transitions to equilibria with the same energy, angular momentum and circulation are possible, they are not the preferred evolutionary path.
Coarsening and solidification via solvent-annealing in thin liquid films
Authors: Yu Tony S. , Bulović Vladimir , Hosoi A. E. 
Published: April 2013

AbstractWe examine solidification in thin liquid films produced by annealing amorphous ${\mathrm{Alq} }_{3} $ (tris-(8-hydroxyquinoline) aluminium) in methanol vapour. Micrographs acquired during annealing capture the evolution of the film: the initially-uniform film breaks up into drops that coarsen, and single crystals of ${\mathrm{Alq} }_{3} $ nucleate randomly on the substrate and grow as slender ‘needles’. The growth of these needles appears to follow power-law behaviour, where the growth exponent, $\gamma $, depends on the thickness of the deposited ${\mathrm{Alq} }_{3} $ film. The evolution of the thin film is modelled by a lubrication equation, and an advection–diffusion equation captures the transport of ${\mathrm{Alq} }_{3} $ and methanol within the film. We define a dimensionless transport parameter, $\alpha $, which is analogous to an inverse Sherwood number and quantifies the relative effects of diffusion- and coarsening-driven advection. For large $\alpha $-values, the model recovers the theory of one-dimensional, diffusion-driven solidification, such that $\gamma \rightarrow 1/ 2$. For low $\alpha $-values, the collapse of drops, i.e. coarsening, drives flow and regulates the growth of needles. Within this regime, we identify two relevant limits: needles that are small compared to the typical drop size, and those that are large. Both scaling analysis and simulations of the full model reveal that $\gamma \rightarrow 2/ 5$ for small needles and $\gamma \rightarrow 0. 29$ for large needles.
Breakfast high in whey protein or carbohydrates improves coping with workload in healthy subjects
Authors: Sihvola Nora , Korpela Riitta , Henelius Andreas , Holm Anu , Huotilainen Minna , Müller Kiti , Poussa Tuija , Pettersson Kati , Turpeinen Anu , Peuhkuri Katri 
Published: April 2013

Dietary components may affect brain function and influence behaviour by inducing the synthesis of neurotransmitters. The aim of the present study was to examine the influence of consumption of a whey protein-containing breakfast drink v. a carbohydrate drink v. control on subjective and physiological responses to mental workload in simulated work. In a randomised cross-over design, ten healthy subjects (seven women, median age 26 years, median BMI 23 kg/m2) participated in a single-blinded, placebo-controlled study. The subjects performed demanding work-like tasks after having a breakfast drink high in protein (HP) or high in carbohydrate (HC) or a control drink on separate sessions. Subjective states were assessed using the NASA Task Load Index (NASA-TLX), the Karolinska sleepiness scale (KSS) and the modified Profile of Mood States. Heart rate was recorded during task performance. The ratio of plasma tryptophan (Trp) to the sum of the other large neutral amino acids (LNAA) and salivary cortisol were also analysed. The plasma Trp:LNAA ratio was 30 % higher after the test drinks HP (median 0·13 (μmol/l)/(μmol/l)) and HC (median 0·13 (μmol/l)/(μmol/l)) than after the control drink (median 0·10 (μmol/l)/(μmol/l)). The increase in heart rate was smaller after the HP (median 2·7 beats/min) and HC (median 1·9 beats/min) drinks when compared with the control drink (median 7·2 beats/min) during task performance. Subjective sleepiness was reduced more after the HC drink (median KSS − 1·5) than after the control drink (median KSS − 0·5). There were no significant differences between the breakfast types in the NASA-TLX index, cortisol levels or task performance. We conclude that a breakfast drink high in whey protein or carbohydrates may improve coping with mental tasks in healthy subjects.