bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel dermal substitute based on biofunctionalized electrospun PCL nanofibrous matrix
Authors: Gümüşderelioğlu Menemşe , Dalkıranoğlu Sevcan , Aydın R. Seda Tığlı , Çakmak Soner 
Published: June 2011

AbstractIn this study, nanofibrous matrices of polycaprolactone (PCL) and PCL/collagen with immobilized epidermal growth factor (EGF) were successfully fabricated by electrospinning for the purpose of damaged skin regeneration. Nanofiber diameters were found to be 284 ± 48 nm for PCL and 330 ± 104 nm for PCL/collagen matrices. The porosities were calculated as 85% for PCL and 90% for PCL/collagen matrices. The covalent immobilization of EGF onto the nanofibrous matrices was verified by the increase of surface atomic nitrogen ratio from 1.0 to 2.4% for PCL and from 3.7 to 4.7% for PCL/collagen. Moreover, EGF immobilization efficiencies of PCL and PCL/collagen matrices were determined as 98.5 and 99.2%, respectively. Human dermal keratinocytes (HS2) were cultivated on both neat and EGF immobilized PCL and PCL/collagen matrices to investigate the effects of matrix chemical composition and presence of EGF on cell proliferation and differentiation. EGF immobilized PCL/collagen matrices exerted early cell spreading and rapid proliferation. Statistically high expression levels of loricrin in HS2 cells cultivated on EGF immobilized PCL/collagen matrices were (p < 0.001) regarding superior differentiation ability of these cells compared to HS2 cells cultured on neat PCL and PCL/collagen matrices. In conclusion, this novel EGF immobilized PCL/collagen nanofibrous matrix could potentially be considered as an alternative dermal substitutes and wound healing material for skin tissue engineering applications. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Nonideality in diffusion of ionic and neutral solutes and hydrogen bond dynamics in dimethyl sulfoxide–chloroform mixtures of varying composition
Authors: Gupta Rini , Chandra Amalendu 
Published: June 2011

AbstractMolecular dynamics simulations of charged and neutral solutes in dimethyl sulfoxide (DMSO)–chloroform mixtures reveal pronounced nonideality in the solute diffusion with changes of composition of the mixtures. The diffusion coefficient of the anionic solute first decreases, passes through a minimum at DMSO mole fraction of about 0.50, and then increases to reach its value for pure DMSO. The diffusion coefficients of the cationic and neutral solutes are found to decrease with increase in DMSO content of the solvent mixture. The extent of nonideality in the diffusion and orientational relaxation of solvent molecules is found to be somewhat stronger than that in diffusion of the anionic solute in these mixtures. We have also calculated the relaxation of hydrogen bonds formed between DMSO and chloroform molecules. The lifetimes of DMSO–chloroform hydrogen bonds are found to increase monotonically with increase in DMSO concentration. The average number of hydrogen bonds and their average energies are also computed. It is found that an increase in DMSO concentration causes a decrease in the number of DMSO–chloroform hydrogen bonds per DMSO or chloroform molecules but increases the strength of these hydrogen bonds. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
A computational study of unique properties of pillar[n]quinones: Self‐assembly to tubular structures and potential applications as electron acceptors and anion recognizers
Authors: Lao Ka‐un , Yu Chin‐hui 
Published: June 2011

AbstractDensity functional theory has been used to calculate the thermodynamic properties and molecular orbitals of pillar[n]quinones. Pillar[n]quinones are expected to be effective electron acceptors and the ability to accept more than one electron increases with the size of the interior cavity. Pillar[5]quinone and pillar[7]quinone show a great intramolecular charge transfer upon the electron excitation from highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) as indicated by a large difference of electron distributions between their HOMO and LUMO and a notable dipole moment difference between the ground and first triplet excited state. The aggregation of pillar[n]quinones leads to tubular dimeric structures joined by 2n CH···O nonclassical hydrogen bonds (HBs) with binding energies about 2 kcal/mol per HB. The longitudinal extension of the supramolecular self‐assembly of pillar[n]quinone may be adjustable through forming and breaking their HBs by controlling the surrounding environment. The tunability of the diameter of the tubular structures can be achieved by changing the number of quinone units in the pillar[n]quinone. The electrostatic potential maps of pillar[n]quinones indicate that the positive charge in the interior cavity decreases as the number of quinone units increases. Chloride and bromide anions are chosen to examine the noncovalent anion‐π interactions between pillar[n]quinones and captured anions. The calculations show that the better compatibility of the effective radius of the anions with the interior dimension of pillar[n]quinone leads to larger stabilization energy. The selectivity of spatial matching and specific interaction of pillar[n]quinone is believed to possibly serve as a candidate for ionic and molecular recognition. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
The 3‐connectivity of a graph and the multiplicity of zero “2” of its chromatic polynomial
Authors: Dong F. M. , Koh K. M. 
Published: June 2011

AbstractLet G be a graph of order n, maximum degree Δ, and minimum degree δ. Let P(G, λ) be the chromatic polynomial of G. It is known that the multiplicity of zero “0” of P(G, λ) is one if G is connected, and the multiplicity of zero “1” of P(G, λ) is one if G is 2‐connected. Is the multiplicity of zero “2” of P(G, λ) at most one if G is 3‐connected? In this article, we first construct an infinite family of 3‐connected graphs G such that the multiplicity of zero “2” of P(G, λ) is more than one, and then characterize 3‐connected graphs G with Δ + δ⩾n such that the multiplicity of zero “2” of P(G, λ) is at most one. In particular, we show that for a 3‐connected graph G, if Δ + δ⩾n and (Δ, δ3)≠(n−3, 3), where δ3 is the third minimum degree of G, then the multiplicity of zero “2” of P(G, λ) is at most one. © 2011 Wiley Periodicals, Inc. J Graph Theory
Inhibition of cyclin‐dependent kinase 5 but not of glycogen synthase kinase 3‐β prevents neurite retraction and tau hyperphosphorylation caused by secretable products of human T‐cell leukemia virus type I‐infected lymphocytes
Authors: Maldonado Horacio , Ramírez Eugenio , Utreras Elias , Pando María E. , Kettlun Ana M. , Chiong Mario , Kulkarni Ashok B. , Collados Lucía , Puente Javier , Cartier Luis , Valenzuela María A. 
Published: June 2011

AbstractHuman T‐cell leukemia virus type I (HTLV‐I)‐associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease characterized by selective loss of axons and myelin in the corticospinal tracts. This central axonopathy may originate from the impairment of anterograde axoplasmic transport. Previous work showed tau hyperphosphorylation at T181 in cerebrospinal fluid of HAM/TSP patients. Similar hyperphosphorylation occurs in SH‐SY5Y cells incubated with supernatant from MT‐2 cells (HTLV‐I‐infected lymphocytes secreting viral proteins, including Tax) that produce neurite shortening. Tau phosphorylation at T181 is attributable to glycogen synthase kinase 3‐β (GSK3‐β) and cyclin‐dependent kinase 5 (CDK5) activation. Here we investigate whether neurite retraction in the SH‐SY5Y model associates with concurrent changes in other tau hyperphosphorylable residues. Threonine 181 turned out to be the only tau hyperphosphorylated residue. We also evaluate the role of GSK3‐β and CDK5 in this process by using specific kinase inhibitors (LiCl, TDZD‐8, and roscovitine). Changes in both GSK3‐β active and inactive forms were followed by measuring the regulatory phosphorylable sites (S9 and Y216, inactivating and activating phosphorylation, respectively) together with changes in β‐catenin protein levels. Our results showed that LiCl and TDZD‐8 were unable to prevent MT‐2 supernatant‐mediated neurite retraction and also that neither Y216 nor S9 phosphorylations were changed in GSK3‐β. Thus, GSK3‐β seems not to play a role in T181 hyperphosphorylation. On the other hand, the CDK5 involvement in tau phosphorylation was confirmed by both the increase in its enzymatic activity and the absence of MT‐2 neurite retraction in the presence of roscovitine or CDK5 siRNA transfection. © 2011 Wiley‐Liss, Inc.
Neuroprotective effect of guanosine against glutamate‐induced cell death in rat hippocampal slices is mediated by the phosphatidylinositol‐3 kinase/Akt/ glycogen synthase kinase 3β pathway activation and inducible nitric oxide synthase inhibition
Authors: Molz Simone , Dal‐Cim Tharine , Budni Josiane , Martín‐de‐Saavedra M.D. , Egea Javier , Romero Alejandro , del Barrio Laura , Rodrigues Ana L.S. , López Manuela G. , Tasca Carla I. 
Published: June 2011

AbstractExcitotoxicity and cell death induced by glutamate are involved in many neurodegenerative disorders. We have previously demonstrated that excitotoxicity induced by millimolar concentrations of glutamate in hippocampal slices involves apoptotic features and glutamate‐induced glutamate release. Guanosine, an endogenous guanine nucleoside, prevents excitotoxicty by its ability to modulate glutamate transport. In this study, we have evaluated the neuroprotective effect of guanosine against glutamate‐induced toxicity in hippocampal slices and the mechanism involved in such an effect. We have found that guanosine (100 μM) was neuroprotective against 1 mM glutamate‐induced cell death through the inhibition of glutamate release induced by glutamate. Guanosine also induced the phosphorylation and, thus, activation of protein kinase B (PKB/Akt), a downstream target of phosphatidylinositol‐3 kinase (PI3K), as well as phosphorylation of glycogen synthase kinase 3β, which has been reported to be inactivated by Akt after phosphorylation at Ser9. Glutamate treated hippocampal slices showed increased inducible nitric oxide synthase (iNOS) expression that was prevented by guanosine. Slices preincubated with SNAP (an NO donor), inhibited the protective effect of guanosine. LY294002 (30 μM), a PI3K inhibitor, attenuated guanosine‐induced neuroprotection, guanosine prevention of glutamate release, and guanosine‐induced GSK3βSer9 phosphorylation but not guanosine reduction of glutamate‐induced iNOS expression. Taken together, the results of this study show that guanosine protects hippocampal slices by a mechanism that involves the PI3K/Akt/GSK3βSer9 pathway and prevention of glutamate‐induced glutamate release. Furthermore, guanosine also reduces glutamate‐induced iNOS by a PI3K/Akt‐independent mechanism. © 2011 Wiley‐Liss, Inc.
High‐throughput analysis of drug dissociation from serum proteins using affinity silica monoliths
Authors: Yoo Michelle J. , Hage David S. 
Published: June 2011

AbstractA noncompetitive peak decay method was used with 1 mm×4.6 mm id silica monoliths to measure the dissociation rate constants (kd) for various drugs with human serum albumin (HSA) and α1‐acid glycoprotein (AGP). Flow rates up to 9 mL/min were used in these experiments, resulting in analysis times of only 20–30 s. Using a silica monolith containing immobilized HSA, dissociation rate constants were measured for amitriptyline, carboplatin, cisplatin, chloramphenicol, nortriptyline, quinidine, and verapamil, giving values that ranged from 0.37 to 0.78 s−1. Similar work with an immobilized AGP silica monolith gave kd values for amitriptyline, nortriptyline, and lidocaine of 0.39–0.73 s−1. These kd values showed good agreement with values determined for drugs with similar structures and/or affinities for HSA or AGP. It was found that a kd of up to roughly 0.80 s−1 could be measured by this approach. This information made it possible to obtain a better understanding of the advantages and possible limitations of the noncompetitive peak decay method and in the use of affinity silica monoliths for the high‐throughput analysis of drug–protein dissociation.
Computational study on OH radical reaction with CHF2CHFCHF2(HFC‐245ea) between 200 and 400 K
Authors: Ali Mohamad Akbar , Rajakumar B. 
Published: June 2011

AbstractThe rate coefficients of the CHF2CHFCHF2 (HFC‐245ea) + OH reaction were computed using G3B3 theory in the temperature range 200 and 400 K. Geometries were optimized for all reactants, transition states, and products at the B3LYP level of theory using 6‐31G* and 6‐311++G** basis sets. Three rotamers (R1, R2, and R3) of CHF2CHFCHF2 were identified using a potential energy surface scan. Thirteen independent transition states were identified and confirmed by intrinsic reaction coordinate calculations. The kinetic parameters due to all different transition states are presented in this paper. All the three rotamers were taken into account in computing the rate coefficients. Throughout the temperature range of this study, rotamer R3 contributes significantly (more than 90%), whereas the other two rotamers R1 and R2 contribute less to the total rate coefficient. The rate coefficients for the title reaction were computed to be k = (1.86 ± 0.17) × 10−13 exp[−(748±26)/T] cm3 molecule−1s−1 and (1.25 ± 0.23) × 10−13 exp[−(587±50)/T] cm3molecule−1 s−1 with Wigner's and Eckart's unsymmetrical tunneling methods, respectively, and they are in reasonable agreement with the experimentally measured ones. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 418–430, 2011
Cellulose‐Based Sustainable Polymers: State of the Art and Future Trends
Authors: Rose Marcus , Palkovits Regina 
Published: June 2011

AbstractNowadays, nearly all polymeric materials are produced from crude oil‐derived monomers. With the steadily increasing demand for oil‐based products and their decreasing availability in the near future, one of the main challenges of mankind is the replacement of crude oil as raw material by renewable resources such as biomass. So far, only a few polymers are available derived directly from cellulose as a main component of biomass by regeneration. On the other hand, a significant potential lies in the production of polymers from cellulose‐derived monomers. A huge variety of different monomers is already available by convenient catalytic processes. This feature article focuses on the current status of mono‐ and resulting polymers derived either directly from cellulose processing and regeneration or by catalytic conversion to a number of monomers for the production of novel polymers and co‐polymers. magnified image
Simultaneous Detection and Removal of Mercury Ions in Aqueous Solution with Fluorescent Conjugated Polymer‐Based Sensor Ensemble
Authors: Kwon Na Young , Kim Daigeun , Son Ji Hye , Jang Geun Seok , Lee Jung Hyo , Lee Taek Seung 
Published: June 2011

AbstractA water‐soluble, sulfur‐containing fluorescent conjugated polymer exhibits a visible fluorescence color change for detection of mercury in the presence of thymine. A new concept provides the design of a sensor ensemble using a simple combination method. This strategy avoids the need for complicated design and synthesis of a recognition group, eliminating the tedious synthetic efforts for the preparation of a sensor material. magnified image
Altered eye‐to‐foot coordination in standing parkinsonian patients during large gaze and whole‐body reorientations
Authors: Anastasopoulos Dimitri , Ziavra Nafsica , Savvidou Eugenia , Bain Peter , Bronstein Adolfo M. 
Published: June 2011

AbstractWe investigated whether turning problems in Parkinson's disease may be the result of abnormal horizontal multisegmental angular coordination. Ten mildly affected patients and controls stood upright and voluntarily reoriented eyes and body to illuminated targets of eccentricities up to ±180 degrees. The effects of target location, visibility, and predictability on movement parameters were evaluated. Patients' latencies were normal. Control subjects foveated large eccentricity targets with a single gaze shift in approximately 30% of predictable trials. Patients rarely did so (10% of predictable trials) because of reduced head‐in‐space and trunk velocity. This resulted in massive foveation delays in patients—an average of half a second for displacements of 180 degrees. The covariation of eye, head, and trunk rotations was quantified statistically by means of principal components analysis. In both groups, the combined movement was initially stereotyped and two principal components accounted for nearly all data variance—the original three mechanical degrees of freedom (i.e., eye‐head‐trunk) are reduced to two kinematic degrees of freedom. However, in patients, the eye contributed more, and the head and trunk less, to the gaze shift than in control subjects. Although the eye‐to‐foot turning synergy is preserved in early‐stage parkinsonism, quantitative differences are prominent, particularly a larger ocular (and smaller head‐trunk) contribution in patients. Turning problems in Parkinson's disease do not result from inability to assemble multisegmental movements, as patients' ability to control numerous degrees of freedom is preserved. However, trunk bradykinesia reduces the frequency of single‐step gaze shifts, thus prolonging target acquisition time. Preserved eye motion compensates for trunk slowness. © 2011 Movement Disorder Society
Pathological gambling in Parkinson's disease—a review of the literature
Authors: Djamshidian Atbin , Cardoso Francisco , Grosset Donald , Bowden‐Jones Henrietta , Lees Andrew J. 
Published: June 2011

AbstractThe prevalence of pathological gambling is 3.4% to 6% in treated Parkinson's disease, which is higher than the background population rate. In this review we discuss current evidence to indicate that dopamine agonists are much more likely to trigger this behavior than either L‐dopa or selective monoamine oxidase B inhibitor monotherapy. New insights from recent behavioral and functional imaging studies and possible treatment approaches are also covered. A PubMed literature search using the terms “gambling” and “Parkinson's disease,” “impulse control disorder,” “impulsive compulsive behaviour,” “dopamine agonist,” of individual dopamine agonists, and of ongoing drug trials, using http://www.clinicaltrials.gov, was carried out for the period up to January 2011. © 2011 Movement Disorder Society
MDS task force on mild cognitive impairment in Parkinson's disease: Critical review of PD‐MCI
Authors: Litvan Irene , Aarsland Dag , Adler Charles H. , Goldman Jennifer G. , Kulisevsky Jaime , Mollenhauer Brit , Rodriguez‐Oroz Maria C. , Tröster Alexander I. , Weintraub Daniel 
Published: June 2011

AbstractThere is controversy regarding the definition and characteristics of mild cognitive impairment in Parkinson's disease. The Movement Disorder Society commissioned a Task Force to critically evaluate the literature and determine the frequency and characteristics of Parkinson's disease–mild cognitive impairment and its association with dementia. A comprehensive PubMed literature review was conducted using systematic inclusion and exclusion criteria. A mean of 26.7% (range, 18.9%–38.2%) of nondemented patients with Parkinson's disease have mild cognitive impairment. The frequency of Parkinson's disease–mild cognitive impairment increases with age, disease duration, and disease severity. Impairments occur in a range of cognitive domains, but single domain impairment is more common than multiple domain impairment, and within single domain impairment, nonamnestic is more common than amnestic impairment. A high proportion of patients with Parkinson's disease–mild cognitive impairment progress to dementia in a relatively short period of time. The primary conclusions of the Task Force are that: (1) Parkinson's disease–mild cognitive impairment is common, (2) there is significant heterogeneity within Parkinson's disease–mild cognitive impairment in the number and types of cognitive domain impairments, (3) Parkinson's disease–mild cognitive impairment appears to place patients at risk of progressing to dementia, and (4) formal diagnostic criteria for Parkinson's disease–mild cognitive impairment are needed. © 2011 Movement Disorder Society
Contrast at high field: Relaxation times, magnetization transfer and phase in the rat brain at 16.4 T
Authors: Pohmann Rolf , Shajan G. , Balla D. Z. 
Published: June 2011

AbstractAs field strength increases, the magnetic resonance imaging contrast parameters like relaxation times, magnetization transfer or image phase change, causing variations in contrast and signal‐to‐noise ratio. To obtain reliable data for these parameters at 16.4 T, high‐resolution measurements of the relaxation times T1, T2 and T2*, as well as of the magnetization transfer ratio and the local frequency in the rat brain were performed. Tissue‐specific values were obtained for up to 17 brain structures to assess image contrast. The measured parameters were compared to those found at different field strengths to estimate contrast and signal behavior at increasing field. T1 values were relatively long with (2272 ± 113) ms in cortex and (2073 ± 97) ms in white matter, but did not show a tendency to converge, leading to an almost linear increase in signal‐to‐noise ratio and still growing contrast‐to‐noise ratio. T2 was short with (25 ± 2) ms in cortex and (20 ± 1) ms in white matter. Magnetization transfer effects increase by around 25% compared to published 4.7 T data, which leads to improved contrast. The image phase, as novel and high‐field specific contrast mechanism, is shown to obtain good contrast in deep brain regions with increasing signal‐to‐noise ratio up to high field strengths. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Compressed‐sensing motion compensation (CosMo): A joint prospective–retrospective respiratory navigator for coronary MRI
Authors: Moghari Mehdi H. , Akçakaya Mehmet , O'Connor Alan , Basha Tamer A. , Casanova Michele , Stanton Douglas , Goepfert Lois , Kissinger Kraig V. , Goddu Beth , Chuang Michael L. , Tarokh Vahid , Manning Warren J. , Nezafat Reza 
Published: June 2011

AbstractProspective right hemidiaphragm navigator (NAV) is commonly used in free‐breathing coronary MRI. The NAV results in an increase in acquisition time to allow for resampling of the motion‐corrupted k‐space data. In this study, we are presenting a joint prospective–retrospective NAV motion compensation algorithm called compressed‐sensing motion compensation (CosMo). The inner k‐space region is acquired using a prospective NAV; for the outer k‐space, a NAV is only used to reject the motion‐corrupted data without reacquiring them. Subsequently, those unfilled k‐space lines are retrospectively estimated using compressed sensing reconstruction. We imaged right coronary artery in nine healthy adult subjects. An undersampling probability map and sidelobe‐to‐peak ratio were calculated to study the pattern of undersampling, generated by NAV. Right coronary artery images were then retrospectively reconstructed using compressed‐sensing motion compensation for gating windows between 3 and 10 mm and compared with the ones fully acquired within the gating windows. Qualitative imaging score and quantitative vessel sharpness were calculated for each reconstruction. The probability map and sidelobe‐to‐peak ratio show that the NAV generates a random undersampling k‐space pattern. There were no statistically significant differences between the vessel sharpness and subjective score of the two reconstructions. Compressed‐sensing motion compensation could be an alternative motion compensation technique for free‐breathing coronary MRI that can be used to reduce scan time. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.