bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of ATP release by human trabecular meshwork cells, the enabling step in purinergic regulation of aqueous humor outflow
Authors: Li Ang , Leung Chi Ting , Peterson‐Yantorno Kim , Stamer W. Daniel , Mitchell Claire H. , Civan Mortimer M. 
Published: March 2011

AbstractOur guiding hypothesis is that ecto‐enzymatic conversion of extracellular ATP to adenosine activates A1 adenosine receptors, reducing resistance to aqueous humor outflow and intraocular pressure. The initial step in this purinergic regulation is ATP release from outflow‐pathway cells by mechanisms unknown. We measured similar ATP release from human explant‐derived primary trabecular meshwork (TM) cells (HTM) and a human TM cell line (TM5). Responses to 21 inhibitors indicated that pannexin‐1 (PX1) and connexin (Cx) hemichannels and P2X7 receptors (P2RX7) were comparably important in modulating ATP release induced by hypotonic swelling, whereas vesicular release was insignificant. Consistent with prior studies of PX1 activity in certain other cells, ATP release was lowered by the reducing agent dithiothreitol. Overexpressing PX1 in HEK293T cells promoted, while partial knockdown (KD) in both HEK293T and TM5 cells inhibited hypotonicity‐activated ATP release. Additionally, KD reduced the pharmacologically defined contribution of PX1 and enhanced those of Cx and P2RX7. ATP release was also triggered by raising intracellular Ca2+ activity with ionomycin after a prolonged lag time and was unaffected by the PX1 blocker probenecid, but nearly abolished by P2RX7 antagonists. We conclude that swelling‐stimulated ATP release from human TM cells is physiologically mediated by PX1 and Cx hemichannels and P2X7 receptors, but not by vesicular release. PX1 appears not to be stimulated by intracellular Ca2+ in TM cells, but can be modulated by oxidation‐reduction state. The P2RX7‐dependent component of swelling‐activated release may be mediated by PX1 hemichannels or reflect apoptotic magnification of ATP release, either through itself and/or hemichannels. J. Cell. Physiol. 227: 172–182, 2012. © 2011 Wiley Periodicals, Inc.
High‐resolution X‐ray CT for 3D petrography of ferruginous sandstone for an investigation of building stone decay
Authors: Cnudde Veerle , Dewanckele Jan , Boone Matthieu , de Kock Tim , Boone Marijn , Brabant Loes , Dusar Michiel , de Ceukelaire Marleen , de Clercq Hilde , Hayen Roald , Jacobs Patric 
Published: March 2011

AbstractDiestian ferruginous sandstone has been used as the dominant building stone for monuments in the Hageland, a natural landscape in east‐central Belgium. Like all rocks, this stone type is sensitive to weathering. Case hardening was observed in combination with blackening of the exterior parts of the dressed stones. To determine the 3D petrography and to identify the structural differences between the exterior and interior parts, X‐ray computed tomography was used in combination with more traditional research techniques like optical microscopy and scanning electron microscopy. The 3D characterization of the ferruginous sandstone was performed with a high‐resolution X‐ray CT scanner (www.ugct.ugent.be) in combination with the flexible 3D analysis software Morpho+, which provides the necessary petrophysical parameters of the scanned samples in 3D. Besides providing the required 3D parameters like porosity, pore‐size distribution, grain size, grain orientation, and surface analysis, the results of the 3D analysis can also be visualized, which enables to understand and interpret the analysis results in a straightforward way. The complementarities between high‐quality X‐ray CT images and flexible 3D software and its relation with the more traditional microscopical research techniques are opening up new gateways in the study of weathering processes of natural building stones. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc
Walks and paths in trees
Authors: Bollobás Béla , Tyomkyn Mykhaylo 
Published: March 2011

AbstractRecently Csikvári [Combinatorica 30(2) 2010, 125–137] proved a conjecture of Nikiforov concerning the number of closed walks on trees. Our aim is to extend this theorem to all walks. In addition, we give a simpler proof of Csikvári's result and answer one of his questions in the negative. Finally we consider an analogous question for paths rather than walks. © 2011 Wiley Periodicals, Inc. J Graph Theory
Convenient synthesis and biological activities of pyridine derivatives of 3,4‐dihydropyrimidin‐2(1H)‐ones
Authors: Zhu Xiao‐Fei , Shi De‐Qing 
Published: March 2011

Abstract2‐Chloro‐5‐(chloromethyl)‐pyridine reacted with 3,4‐dihydropyrimidin‐2(1H)‐ones 1 to afford 1‐[6‐aryl‐1‐(6‐chloropyridin‐3‐yl‐methyl)‐2‐(6‐chloropyridin‐3‐yl‐methylthio)‐4‐methyl‐1,6‐dihydropyrimidin‐5‐yl] carboxylates or ethanones 2 in good yields. The structure of the target compounds 2 was confirmed by IR, 1H NMR, EI‐MS, and elemental analyses, and compound 2a was further characterized by single crystal X‐ray diffraction. The preliminary bioassay indicated that some of the title compounds possess moderate insecticidal and fungicidal activities. J. Heterocyclic Chem., (2011).
Reaction of cyclic imidates with α,β‐unsaturated esters: Synthesis of new pyrrolo[2,1‐b]‐1,3‐oxazine and pyrido[2,1‐b]‐1,3‐oxazine derivatives
Authors: Ihara Shogo , Soma Takashi , Yano Daigo , Aikawa Shunichi , Yoshida Yasuhiko 
Published: March 2011

AbstractThe cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a, 1b, 1c, 1d, 1e, 1f, with dimethyl acetylenedicarboxylate 2, trimethyl ethylenetricarboxylate 4, or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a, 3b, 3c, 3d, 3e, 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b, 5c, 5d, 5e, 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a, 7b, 7c, 7d, 7e, 7f (32–59%), respectively. In these reactions, 1a, 1b, 1c, 1d, 1e, 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2, 4, and 6 to give annulation products 3, 5, and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011).
Microwave‐assisted one‐pot synthesis of functionalized pyrimidines using ionic liquid
Authors: Raghuvanshi Dushyant Singh , Singh Krishna Nand 
Published: March 2011

AbstractAn efficient one‐pot multicomponent synthesis of 2,4‐diamino‐5‐pyrimidinecarbonitrile derivatives has been achieved in excellent yields by the condensation of aromatic aldehydes, malononitrile, and guanidine using ionic liquid under controlled microwave irradiation (100 W) at 60°C. This green approach offers a number of advantages in terms of methodology, high‐product yield, short reaction time, mild reaction conditions, and easy workup. J. Heterocyclic Chem., (2011).
The effects of multiple freeze–thaw cycles on the biomechanical properties of the human bone‐patellar tendon‐bone allograft
Authors: Jung Ho‐Joong , Vangipuram Gautum , Fisher Matthew B. , Yang Guoguang , Hsu Shanling , Bianchi John , Ronholdt Chad , Woo Savio L‐Y. 
Published: March 2011

AbstractSoft tissue allografts, such as the bone‐patellar tendon‐bone (BPTB) graft, have been frequently used for anterior cruciate ligament (ACL) reconstruction. As allografts are subjected to freezing and thawing for multiple cycles, the objective of this study was to measure the changes of the biomechanical properties of the human BPTB allograft after 4 and 8 freeze–thaw cycles in comparison to a single freeze–thaw cycle. Three BPTB specimens were procured from 21 human donors and divided into three groups: 1, 4, or 8 freeze–thaw cycles. Each freeze–thaw cycle consisted of freezing at −20 ± 10°C for more than 6 h and thawing at 22 ± 3°C for at least 6 h. Tensile testing of the BPTB specimens consisted of loading between 50 N and 250 N for 100 cycles and then loading to failure. Cyclic loading revealed a similar amount of creep (∼0.5 mm) among the three freeze–thaw cycles groups (p = 0.38). The stiffness of the BPTB graft for the 1, 4, and 8 freeze–thaw cycle groups were 244 ± 42 N/mm, 235 ± 39 N/mm, and 231 ± 40 N/mm, respectively (p = 0.43). Similar findings were obtained for the ultimate load of the BPTB graft (p = 0.14) and the tangent modulus of the PT substance (p = 0.41). The results of this study suggest that there would be little measurable effect on the structural properties of the BPTB graft or mechanical properties of the PT tissue substance following 8 freeze–thaw cycles. These BPTB allografts could potentially be re‐frozen without a loss in their biomechanical properties, given appropriate storage and care. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1193–1198, 2011
Determination of fluoroquinolones in blood by matrix solid‐phase dispersion extraction and CE
Authors: Li Dan , Yang Qiuling , Wang Ziming , Su Rui , Xu Xu , Zhang Hanqi 
Published: March 2011

AbstractA simple and rapid method for the determination of residues of four fluoroquinolones in blood samples was developed. The method was based on matrix solid‐phase dispersion extraction followed by CE with ultraviolet detection. 1‐Butyl‐3‐methylimidazolium tetrafluoroborate aqueous solution was used as the background electrolyte for the separation of fluoroquinolones. The average recoveries of the four fluoroquinolones at two spiked levels ranged from 54.0 to 86.4% for pig blood, and 45.4 to 79.9% for deer blood, with the relative standard deviations <9.45%. Detection limits for the four fluoroquinolones in blood sample ranged from 0.15 to 0.31 μg/mL.
Development and validation of two methods based on high‐performance liquid chromatography‐tandem mass spectrometry for determining 1,2‐benzopyrone, dihydrocoumarin, o‐coumaric acid, syringaldehyde and kaurenoic acid in guaco extracts and pharmaceutical preparations
Authors: Gasparetto João C. , Guimarães de Francisco Thais M. , Campos Francinete R. , Pontarolo Roberto 
Published: March 2011

AbstractIn this study, two HPLC‐ESI‐MS/MS methods were developed and validated for the determination of 1,2‐benzopyrone (COU), o‐coumaric acid (OCA), kaurenoic acid (KAU), syringaldehyde (SYR), and dihydrocoumarin (DIH) in guaco extracts and pharmaceutical preparations (syrup and oral solution). The chromatographic separation was achieved using a C18 XBridge 150×2.1‐mm (5‐μm particle size) column maintained at 25°C. The mobile phases consisted of a gradient of water and acetonitrile containing 0.05% formic acid or 5 mM ammonium formate for the positive and negative ion modes, respectively. All of the calibration curves showed excellent coefficients of correlation (r≥0.9970) over the ranges of 1.25–400 ng/mL for coumarin, 10–600 ng/mL for dihydrocoumarin, 5–250 ng/mL for KAU, and 25–500 ng/mL for o‐coumaric acid and syringaldehyde. The range of recovery was 96.3–103% with an RSD% of <4.85% for intraday and interday precision. The results indicate that the developed methods are fast, efficient, and sensitive for the quantification of the guaco metabolites in extracts and pharmaceutical forms while avoiding purification and derivatization steps.
Ultrasound‐assisted extraction of phenolic antioxidants from Acacia confusa flowers and buds
Authors: Tung Yu Tang , Chang Wei Chun , Chen Ping Sheng , Chang Tzu Cheng , Chang Shang Tzen 
Published: March 2011

AbstractAcacia confusa Merr. (Leguminosae), a species native to Taiwan, is widely distributed on the hills and lowlands of Taiwan, and has been used in traditional medicines. In this study, the application of ultrasound‐assisted extraction was used to extract the phenolic compounds from A. confusa flowers and buds for the first time. Among the extraction methods, it can significantly enhance the contents of phenolic compounds and antioxidant activities in A. confusa flower and bud extracts using ultrasound‐assisted extraction (10 min×12 times). Considering both the solvent consumption and the time needed for extraction, ultrasound‐assisted extraction was found to be the most practical approach for the rapid and efficient extraction of bioactive phenolic constituents. In addition, gallic acid, myricitrin‐3‐rhamnoside, quercitrin‐3‐rhamnoside, europetin‐3‐rhamnoside, kaempferol‐3‐rhamnoside, rhamnetin‐3‐glucoside, and rhamnetin‐3‐rhamnoside were also quantified in different extracts by RP‐HPLC. It is clear that ultrasound‐assisted extraction is an efficient method for extracting phenolic compounds from A. confusa flowers and buds.
Extraction of ketamine from urine using a miniature silica monolithic cartridge followed by quantification with liquid chromatography tandem mass spectrometry (LC‐MS/MS)
Authors: Nema Tarang , Chan Eric C. Y. , Ho Paul C. 
Published: March 2011

AbstractThe high surface area monolith with reactive hydroxyl group on its surface enables it to function as a miniature solid‐phase extraction (SPE) cartridge in size of 1 cm in diameter and 0.5 cm in length. The prepared silica monolith was characterized by Brunauer–Emmett–Teller method, scanning electron microscopy, X‐ray diffraction and Fourier transform infrared (FTIR) spectroscopy. Ketamine was selected as model analyte to validate the extraction efficiency of the prepared cartridge. The extracted ketamine from urine sample was quantitated by liquid chromatography tandem mass spectrometry (LC‐MS/MS) using positive electrospray ionization. The limit of detection and quantification for ketamine was found to be 0.5 and 1.6 ng/mL, respectively. The analysis exhibited linearity in the range of 10–500 ng/mL with coefficient of correlation >0.99. The recovery was found to be in the range of 89–107% with relative standard deviation (RSD) less than 10%. The prepared cartridge was found robust in extracting ketamine efficiently and repeatedly without any significant deterioration in its performance. Moreover, the batch‐to‐batch variations in the performance of the prepared cartridges in terms of % ion suppression of the extracts and recoveries of samples were small, suggesting the consistency in the properties of the monolith.
Determining the efficacy and cost‐effectiveness of the activalve: Results of a long‐term prospective trial
Authors: Graville Donna J. , Palmer Andrew D. , Andersen Peter E. , Cohen James I. 
Published: March 2011

AbstractObjectives/Hypothesis:To investigate 1) whether the Provox ActiValve results in increased device‐life in individuals with below average device‐life, 2) whether it is cost‐effective, and 3) whether it has any impact on voice‐related quality of life.Study Design:Prospective study.Methods:Individuals who experienced below‐average tracheoesophageal prosthesis (TEP) life were studied.Results:Individuals with persistent below‐average TEP life were enrolled in the study and underwent periodic re‐evaluation. The majority (73%) experienced significant improvement as a result of use of the device. Those who continued to wear the device were followed for an average of 30.45 months (range, 14.70–43.49 months) and wore a total of 31 devices over this time. They demonstrated an average increase in device‐life of more than 500%, going from an average of 1.93 months with a traditional indwelling device to 10.30 months with the ActiValve. The majority of individuals found that voicing with the ActiValve was either the same or better than with their previous indwelling TEP. Voice‐related quality of life was not significantly different from that of a group of controls. Overall satisfaction with the device was high, and the majority would have chosen the ActiValve in the future. Overall, there were estimated to be cost savings to third‐party payers through use of the ActiValve in this population.Conclusions:The ActiValve is effective in increasing device‐life in selected patients who have failed conservative measures. Our protocol for use of the device requires individuals to meet several usage criteria before initial placement and to return for periodic monitoring.
Reticulation de resines epoxydes sous microondes
Authors: Thuillier FrançOise Marie , Jullien Henri , Grenier‐Loustalot Marie‐Florence 
Published: March 2011

AbstractA microwave treatment has been applied to the curing of a DGEBA epoxy resin with an aromatic diamine (DDS). The aim of study is to understand the energy transfer processes and the crosslinking mechanisms induced by pulsed microwave treatment. The “pulsed” technique induces an increase in the electrical field inside the polymer without changing the overall energy transfer, as compared with continuous microwave treatment of the same average power level. The cured samples were investigated by Fourier Transform Infra‐red, 13C solid state NMR and dynamic mechanical measurements. Network structures were found to be affected by pulse repetition period and peak pulse power.
L'influence des thermal spikes sur le comportement d'absorption d'humidite de CFC
Authors: Woehlecke M. , Kuzenko M. V. , Uedelhoven W. 
Published: March 2011

AbstractFor the judgement of mechanical properties of carbon fibre reinforced plastics (CFRP) the knowledge of the moisture absorption behaviour is of essential importance. The influence of constant environmental conditions of CFRP has already been the subject of extensive investigations, but the effects of rapid high temperature excursions (“thermal spikes”) are not yet very well understood. These thermal spikes are encountered on the surface of aircraft components during supersonic flights.This paper describes a laboratory method for the simulation of thermal spikes. Investigations have been carried out on four different epoxy systems. The influence of thermal spikes with different heating rates on the moisture absorption behaviour of CFRP is reported.
Brain diffusion‐weighted imaging in Friedreich's ataxia
Authors: Rizzo Giovanni , Tonon Caterina , Valentino Maria Lucia , Manners David , Fortuna Filippo , Gellera Cinzia , Pini Antonella , Ghezzo Alessandro , Baruzzi Agostino , Testa Claudia , Malucelli Emil , Barbiroli Bruno , Carelli Valerio , Lodi Raffaele 
Published: March 2011

AbstractBackground:Friedreich ataxia (FRDA) is the commonest form of autosomal recessive ataxia. This study aimed to define the extent of the brain damage in FRDA patients and to identify in vivo markers of neurodegeneration, using diffusion‐weighted imaging (DWI).Methods:We studied 27 FRDA patients and 21 healthy volunteers using a 1.5 T scanner. Axial DW images were obtained and mean diffusivity (MD) maps were generated. Region of interests (ROIs) included medulla, pons, inferior, middle and superior cerebellar peduncles (ICP, SCP, MCP), dentate nucleus, cerebellar white matter, thalamus, caudate, putamen, pallidus, pyramidal tracts at level of posterior limb of internal capsule (PLIC), optic radiations (OR), and corpus callosum. Histograms of MD were generated for all pixels in the whole cerebral hemispheres and infratentorial compartment. Disease severity was assessed by the International Cooperative Ataxia Rating Scale (ICARS).Results:FRDA patients had significantly higher MD values than controls in medulla (P < 0.001), ICP (P < 0.001), MCP (P < 0.01), SCP (P < 0.001), OR (P < 0.001), and at the level of the infratentorial structures such as brainstem (P < 0.01), cerebellar hemispheres (P < 0.01), and especially in the cerebellar vermis (P < 0.001). MD values were strongly correlated with disease duration and ICARS score.Discussion:Our results showed that DWI is a suitable non‐invasive technique to quantify the extent of neurodegeneration in FRDA, that appears more extended than previously reported, showing a microstructural involvement of structures such as OR and MCP. © 2011 Movement Disorder Society
In vivo evidence for GABAA receptor changes in the sensorimotor system in primary dystonia
Authors: Garibotto Valentina , Romito Luigi M. , Elia Antonio E. , Soliveri Paola , Panzacchi Andrea , Carpinelli Assunta , Tinazzi Michele , Albanese Alberto , Perani Daniela 
Published: March 2011

AbstractBackground:Preclinical and clinical evidence suggests that impaired gamma‐aminobutyric (GABA) control, leading to disinhibition within the sensorimotor system, might play a role in dystonia. Aim of this study is the in vivo assessment of the GABAergic system in dystonia using positron emission tomography (PET) and 11C‐flumazenil, a selective GABAA receptor ligand.Methods:Fourteen subjects with primary dystonia (9 carriers of the DYT1 mutation and 5 sporadic cases) were compared to 11 controls, using a simplified reference tissue model to measure binding potential.Results:Voxel‐based analyses showed a reduction in GABAA receptor expression/affinity both in DYT1 carriers and sporadic patients in primary motor and premotor cortex, primary and secondary somatosensory cortex, and in the motor component of the cingulate gyrus.Conclusions:Dysfunction of GABAA receptors in sensorimotor systems in primary (genetic and sporadic) dystonia supports the view that lack of GABAergic control may be associated with the generation of dystonic movements. © 2011 Movement Disorder Society
Interpreting the results of Parkinson's disease clinical trials: Time for a change
Authors: Holford Nick H. G. , Nutt John G. 
Published: March 2011

AbstractRandomized clinical trials testing putative disease‐modifying agents in Parkinson's disease (PD) have yielded controversial results that have not influenced evidence‐based recommendations for the treatment of PD. We argue that the failure of these clinical trials may be linked to end point‐based statistical analyses that must make prior assumptions about the magnitude and the time course of wash‐in and wash‐out of drug effects. Many of these shortcomings may be avoided with quantitative modeling of the entire time course of the clinical trial and examining evidence for three concomitant processes, disease progression, symptomatic drug effects and disease modifying effects. The power of this approach is illustrated by modeling of DATATOP and ELLDOPA trial data. © 2010 Movement Disorder Society
ICAM1 and fibrinogen‐γ are increased in uterine epithelial cells at the time of implantation in rats
Authors: Lecce Laura , Kaneko Yui , Madawala Romanthi J. , Murphy Christopher R. 
Published: March 2011

AbstractUterine epithelial cells transform into a receptive state to adhere to an implanting blastocyst. Part of this transformation includes the apical concentration of cell adhesion molecules at the time of implantation. This study, for the first time, investigates the expression of ICAM1 and fibrinogen‐γ (FGG) in uterine epithelial cells during normal pregnancy, pseudopregnancy and in hormone‐treated rats. An increase (P < 0.05) in ICAM1 was seen at the apical membrane of uterine epithelial cells at the time of implantation compared with day 1 of pregnancy. ICAM1 was also increased (P < 0.05) on day 6 of pseudopregnancy as well as in ovariectomized rats treated with progesterone plus oestrogen. These results show that ICAM1 up‐regulation at the time of implantation is under the control of progesterone, and is not dependent on cytokine release from the blastocyst or in semen. FGG dimerization increased (P < 0.05) on day 6 of pregnancy compared with day 1, and was not up‐regulated in day 6 pseudopregnant animals, suggesting this increase is dependent on a developing blastocyst. The presence of ICAM1 and FGG in the uterine epithelium at the time of implantation in the rat is similar to that seen in lymphocyte–endothelium adhesion, and we suggest a similar mechanism in embryo–uterine epithelium adhesion is utilized. Mol. Reprod. Dev. 78:318–327, 2011. © 2011 Wiley‐Liss, Inc.