bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intermolecular interactions—From some general features to conformational autocatalysis
Authors: Piela Lucjan 
Published: July 2012

AbstractThe intermolecular interaction is ubiquitous and influences the results of virtually every chemical or physical experiment. There are some important questions left in the theory of intermolecular interaction. One of such questions is: what kind of objects do interact. In the article, we recall a kind of unusual symmetry requirement in a physical theory related to this question. Also, we introduce a gradation of such choices of the interacting subsystems leading eventually to the concept of the most natural choice. Electrostatics plays a special role in the intermolecular interaction. We discuss why electrostatics remains important even if other interactions are strong. Next, the electrostatic interactions are shown to be important in the three‐dimensional (3D) structure of proteins occurring in Nature. Predicting the molecule's lowest‐energy conformation or configuration represents a formidable task. There were many attempts to solve this problem for protein molecules, for which it is believed their native conformation corresponds to the lowest free energy. The challenge to find this conformation from a given sequence of amino acids (AAs) is known as a “second genetic code.” In fact all of these attempts are based on some smoothing of the energy landscape. In the article, some of these smoothing techniques are described, which finally turned out to be highly successful in finding native structures of globular proteins. When discussing the contributions to the conformational energy the importance of the electrostatic interactions has been stressed. In particular, it turned out that the dipole moments of the NH and of the CO bonds in proteins functioning in nature are oriented to good accuracy along the local intramolecular electric field. Thanks to an enormous effort of the protein folding community it is possible to predict the native 3D structure of globular proteins. It is also possible to design such AA sequences, which fold to the desired protein 3D structure. A certain reliable theoretical technique of protein folding has been used to study a possibility of conformational autocatalysis. It turned out that such an effect has been predicted for a small protein of 32 AAs, with carefully designed AA sequence. This may be seen as a model of the prion disease propagation. © 2012 Wiley Periodicals, Inc.
A liquid chromatography/electrospray ionization tandem mass spectrometric method for quantification of asiatic acid from plasma: application to pharmacokinetic study in rats
Authors: Nair Sreenath Nandakumar , Menon Sasikumar , Shailajan Sunita 
Published: July 2012

RATIONALEAsiatic acid (AA), a pentacyclic triterpene from Centella asiatica (L.) Urban, has shown numerous therapeutic activities. However, none of the published works to date has used high‐performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) for determination of AA from biological fluids. Therefore, the present paper describes a sensitive HPLC/electrospray ionization (ESI)‐MS/MS method for quantification of AA in rat plasma.METHODSAmmonium adduct formation of AA was essential in the development of a sensitive method with the rat plasma samples being pre‐treated by a simple solid‐phase extraction method. The separation was achieved on a Cosmosil C18 column using a gradient mobile phase flow. Detection was performed using an Applied Biosystems API Q‐Trap 2000 mass spectrometer equipped with an ESI source operated in positive mode with colchicine used as internal standard.RESULTSAn eight‐point calibration curve over the concentration range of 1.02–407.88 ng/mL for AA from rat plasma provided an optimum linear detector response (with r2 >0.9983). The mean percentage recovery (n = 3) for the low, middle and high quality control samples was 91.23 ± 1.88%, 90.36 ± 0.55% and 89.71 ± 0.21%, respectively. The intra‐day and inter‐day precision and accuracy of the quality control samples were within ≤5% and ±7% correspondingly.CONCLUSIONSThe developed method was validated as per US FDA guidelines and applicability demonstrated by successful measurement of AA from plasma following oral administration of C. asiatica extracts to Wistar rats. The results suggest that the method could be applied to therapeutic monitoring of AA and pharmacokinetic studies in human volunteers. Copyright © 2012 John Wiley & Sons, Ltd.
Oxygen isotopic composition of fulgurites from the Egyptian Sahara and other locations
Authors: Longinelli Antonio , Serra Romano , Sighinolfi Giampaolo , Selmo Enricomaria , Sgavetti Maria 
Published: July 2012

RATIONALEFulgurites are glassy crusts or hollow glassy tubes formed by the impact of a lightning strike on a target material on the Earth's surface. The oxygen isotopic composition of fulgurites has never been measured and, consequently, it is unknown whether or not isotopic fractionations take place between the target material and the fulgurite glass during the lightning event which is an excellent natural example of extremely fast melting process.METHODSFollowing well‐established procedures (high‐temperature reaction of the fulgurite material with BrF5, conversion into CO2 of the evolved O2 and measurement of the18O/16O ratio on a Finnigan Delta S mass spectrometer) we measured for the first time the oxygen isotopic composition of sets of fulgurites coming from various locations on the Earth's surface.RESULTSThe range of isotopic values is quite large, probably reflecting the oxygen isotopic values of the target materials. In the case of fulgurites from the Sahara Desert the isotopic values obtained from the bulk material, quartz crystals sticking to the fulgurite body, tiny samples of loose sand coming from fulgurite bubbles, and sand samples collected near the fulgurites, are very close to one another.CONCLUSIONSAlthough we do not have indisputable evidence, we conclude that, at least in the case of oxygen, the fusion process of the material struck by lightning, as well as all the extremely fast high‐temperature fusion processes, probably take place without any isotopic fractionation effect. Copyright © 2012 John Wiley & Sons, Ltd.
Network meta‐analysis models to account for variability in treatment definitions: application to dose effects
Authors: Giovane Cinzia Del , Vacchi Laura , Mavridis Dimitris , Filippini Graziella , Salanti Georgia 
Published: July 2012

For a network meta‐analysis, an interlinked network of nodes representing competing treatments is needed. It is often challenging to define the nodes as these typically refer to similar but rarely identical interventions.The objectives of this paper are as follows: (i) to present a series of network meta‐analysis models that account for variation in the definition of the nodes and (ii) to exemplify the models where variation in the treatment definitions relates to the dose. Starting from the model that assumes each node has a ‘fixed’ definition, we gradually introduce terms to explain variability by assuming that each node has several subnodes that relate to different doses. The effects of subnodes are considered monotonic, linked with a ‘random walk’, random but exchangeable, or have a linear pattern around the treatment mean effect. Each model can be combined with different assumptions for the consistency of effects and might impact on the ranking of the treatments. Goodness of fit, heterogeneity and inconsistency were assessed. The models are illustrated in a star network for the effectiveness of fluoride toothpaste and in a full network comparing agents for multiple sclerosis.The fit and parsimony measures indicate that in the fluoride network the impact of the dose subnodes is important whereas in the multiple sclerosis network the model without subnodes is the most appropriate. The proposed approach can be a useful exploratory tool to explain sources of heterogeneity and inconsistency when there is doubt whether similar interventions should be grouped under the same node. Copyright © 2012 John Wiley & Sons, Ltd.
Concise Review: A High-Content Screening Approach to Stem Cell Research and Drug Discovery
Authors: Xia Xiaofeng , Wong Stephen T. 
Published: July 2012

AbstractHigh-throughput screening (HTS) is a technology widely used for early stages of drug discovery in pharmaceutical and biotechnology industries. Recent hardware and software improvements have enabled HTS to be used in combination with subcellular resolution microscopy, resulting in cell image-based HTS, called high-content screening (HCS). HCS allows the acquisition of deeper knowledge at a single-cell level such that more complex biological systems can be studied in a high-throughput manner. The technique is particularly well-suited for stem cell research and drug discovery, which almost inevitably require single-cell resolutions for the detection of rare phenotypes in heterogeneous cultures. With growing availability of facilities, instruments, and reagent libraries, small-to-moderate scale HCS can now be carried out in regular academic labs. We envision that the HCS technique will play an increasing role in both basic mechanism study and early-stage drug discovery on stem cells. Here, we review the development of HCS technique and its past application on stem cells and discuss possible future developments.
Mesenchymal Stem Cells Shape Microglia Effector Functions Through the Release of CX3CL1
Authors: Giunti Debora , Parodi Benedetta , Usai Cesare , Vergani Laura , Casazza Simona , Bruzzone Santina , Mancardi Gianluigi , Uccelli Antonio 
Published: July 2012

AbstractMesenchymal stem cells (MSC) display a remarkable ability to modulate the immune response and protect the central nervous system mainly through the release of soluble factors in a paracrine fashion, affecting the functional behavior of cells in the tissues. Here we investigated the effect of the interaction between MSC and microglia in vitro, and we dissected the molecular and cellular mechanisms of this crosstalk. We demonstrated that MSC impair microglia activation by inflammatory cues through the inhibition of the expression and release of inflammatory molecules and stress-associated proteins. We showed that MSC significantly increase microglial expression and release of molecules associated with a neuroprotective phenotype such as CX3CR1, nuclear receptor 4 family, CD200 receptor, and insulin growth factor 1. Interestingly, MSC can enhance functional changes on microglia as depicted by the increase of intracellular calcium concentration and phagocytic activity. This last event is associated with an increased expression of triggering receptor expressed on myeloid cells-2, an innate immune receptor involved in phagocytosis in the absence of inflammation. The observed effects on CX3CR1-expressing microglia are due to the release of CX3CL1 by MSC, driven by inflammatory signals, as demonstrated by the reversal of the observed results when CX3CL1 expression was silenced in MSC or its release was blocked. Finally, we showed that exogenous CX3CL1 induce phenotypic and functional changes of microglia similar to those induced by MSC. These findings demonstrate that MSC instruct, through the release of CX3CL1, microglia responsiveness to proinflammatory signals by modulating constitutive “calming” receptors, typically expressed by “steady-state microglia” thus switching microglia from a detrimental phenotype to a neuroprotective one.
Integrated solar thermochemical cycles for energy storage and fuel production
Authors: Petrasch Jörg , Klausner James 
Published: July 2012

AbstractIntegrated solar thermochemical cycles comprise a range of promising novel process technologies that use concentrated solar energy to drive endothermic chemical reactions at elevated temperatures. The most promising application is the production of carbon‐neutral fuels, particularly via single or multistep water and CO2 splitting or via the solar thermochemical upgrading of carbonaceous fuels such as biomass, waste, or oil residues. Furthermore, intermediate storage of solar energy in reversible reactions, the so‐called solar thermochemical heat pipes, shows great promise to replace latent heat storage for concentrating solar power generation. Potential niche applications are material processing and material testing. Widespread deployment of solar thermochemical cycles hinges on the development of several key technologies: (i) reaction systems and catalysts able to endure tens of thousands of conversion cycles without significant degradation, (ii) reactors and heat recuperation systems that fully exploit the theoretical potential of solar thermochemical cycles, (iii) industrial‐scale reactor technologies, and (iv) process control technologies that address the inherently transient nature of solar power.This article is categorized under:

Concentrating Solar Power > Science and Materials
Electrolytes for solid oxide fuel cells
Authors: Figueiredo F. M. L. , Marques F. M. B. 
Published: July 2012

AbstractSolid oxide fuel cells are extremely flexible energy conversion systems able to operate within a broad temperature range (500–1000°C), with a variety of fuels (from hydrogen to liquid fuels), including concepts able to be scaled to deliver power from the milliwatt to the megawatt range. The solid electrolyte, as an ionic charge carrier, is one central component that determines the operational characteristics of the fuel cell system, namely the working temperature. Design of new electrolytes includes manipulation of ionic defects concentration and mobility. Here, particular attention is given to the impact on ionic transport of point defects in various types of structures, dislocations, grain boundaries, and heterostructure interfaces. Properties derived from structural and compositional characteristics, but also from microstructural features, including recent complex engineered thin films, are reviewed. Major families of materials are compared with respect to key performance parameters. Finally, the effects of composition, structure, microstructure, and strain on ionic transport are assessed as complementary tools for future developments in solid electrolyte materials.This article is categorized under:

Fuel Cells and Hydrogen > Science and Materials
Energy Research & Innovation > Science and Materials
Poor prognosis of KRAS or BRAF mutant colorectal liver metastasis without microsatellite instability
Authors: Umeda Yuzo , Nagasaka Takeshi , Mori Yoshiko , Sadamori Hiroshi , Sun Dong‐Sheng , Shinoura Susumu , Yoshida Ryuich , Satoh Daisuke , Nobuoka Daisuke , Utsumi Masashi , Yoshida Kazuhiro , Yagi Takahito , Fujiwara Toshiyoshi 
Published: July 2012

AbstractBackgroundThe discovery of practical biomarkers is important to realize personalized medicine for patients with malignant neoplasias, including colorectal cancer (CRC).PurposeThe aim of this study was to determine reliable prognostic biomarkers by the analysis of patients with resectable colorectal liver metastases (CRLM).MethodsGenomic DNA was obtained from the CRLM tissues of a cohort of 126 patients with CRLM with curative hepatic resection. The KRAS/BRAF mutation spectrum and microsatellite instability (MSI) status were successfully analyzed in 100 of the 126 CRLM tissues and these findings were examined in relation to the patients' clinical outcomes.ResultsThe cohort of 100 CRLM patients consisted of 46 with synchronous and 54 with metachronous liver metastasis. Overall survival and disease‐free survival at 5 years were 57.4 and 24.9 %, respectively. MSI analysis revealed that none of the 100 CRLM specimens showed any evidence of MSI. By KRAS/BRAF mutation analysis, the analyzed CRLM patients were divided into 3 groups;KRAS‐mutant (KRAS‐Mt;n = 27), BRAF‐mutant (BRAF‐Mt;n = 3), and wild‐types of both genes (Wild‐type;n = 70). In the survival analysis, both KRAS‐Mt and BRAF‐Mt patients showed significantly poorer prognoses compared with Wild‐type patients. Furthermore, although the population with the BRAF mutation was small, this mutation had a significant negative impact on disease‐free survival.ConclusionsIn this study, all tumors in the cohort of CRLM patients were non‐MSI tumors, suggesting MSI cancer in primary CRC would rarely reveal metastatic potential. KRAS and BRAF mutations are suggested to be poor prognostic factors in CRLM. Genetic information has an essential role as a prognostic marker and could contribute to the decisions on treatment strategy for CRLM.
Young Adults’ Experience of Living with Neurofibromatosis Type 1
Authors: Hummelvoll Grete , Antonsen Kjell Magnus 
Published: July 2012

AbstractNeurofibromatosis Type 1 (NF1) may have many psychosocial consequences for affected adults. More knowledge is needed about the experience of psychosocial aspects in different stages of adulthood. This qualitative study aims to describe the experiences and concerns of persons living with NF1 in the early stages of adulthood. In semi‐structured interviews, Norwegian adults with NF1 (n = 15) between 18 and 37 years of age described their experiences and concerns. Interview transcripts were analysed in a both concept and data driven way. Severity of NF1 was assessed from interview data. Our data indicate that many informants have more friends than in childhood, including friends with NF1. An important topic is whether or not to inform others about the NF1 diagnosis . Low self‐confidence is common, often related to early school failure and bullying or to visible neurofibromas. The unpredictable development of NF1 causes much concern. The experience of NF1's impact seems less associated with the assessed severity than with social network, relation to the labour market, and psychological factors.
Estimation of Micellization Parameters of SDS in the Presence of Some Electrolytes for Emulsion Polymerization Systems
Authors: Naderi Miqan Saeed , Farshchi Tabrizi Farshad , Abedini Hossein , Atashy Kashi Hossein 
Published: July 2012

AbstractThe critical micelle concentration and the effective degree of dissociation of micelles (α) of sodium dodecyl sulfate, which is the most extensively used surfactant in emulsion polymerization systems, were determined in the presence of various amounts of sodium carbonate and potassium persulfate, and some monomers, such as methyl methacrylate, butyl acrylate, and styrene by means of the conductometric procedure at 25 °C. In addition, the other micellization parameters, such as aggregation number and number of counter‐ions per micelle, were computed directly from the obtained conductivity measurements data. The effect of the combination of sodium carbonate and potassium persulfate, on the critical micelle concentration of the sodium dodecyl sulfate solutions was studied at 60 °C (emulsion reaction temperature). The empirical formulations derived provide an easy way to estimate the critical micelle concentration and the effective degree of dissociation of micelles of a system at a given electrolyte and monomer concentration.
Free Fatty Acid Derivative HUHS2002 Potentiates α7 ACh Receptor Responses Through Indirect Activation of CaMKII
Authors: Kanno Takeshi , Shimizu Tadashi , Tanaka Akito , Nishimoto Takaaki , Nishizaki Tomoyuki 
Published: July 2012

AbstractThe present study examined the effect of 4‐[4‐(Z)‐hept‐1‐enyl‐phenoxy] butyric acid (HUHS2002), a free fatty acid derivative, on α7 acetylcholine (ACh) receptor responses. HUHS2002 potentiated whole‐cell membrane currents through α7 ACh receptors expressed in Xenopus oocytes in a concentration (1–100 nM)‐dependent manner, reaching about 140 % of the original amplitude at 100 nM 50 min after a 10‐min treatment. The HUHS2002 effect was prevented by KN‐93, an inhibitor of Ca2+/calmodulin‐dependent protein kinase II (CaMKII), while it was not affected by GF109203X, an inhibitor of protein kinase C (PKC), or H‐89, an inhibitor of protein kinase A (PKA). In the in situ CaMKII assay using cultured rat hippocampal neurons, HUHS2002 activated CaMKII and the activation was abolished by KN‐93. In the cell‐free assay of protein phosphatase 1 (PP1), HUHS2002 partially inhibited PP1 activity. Taken together, these results indicate that HUHS2002 potentiates α7 ACh receptor responses by indirectly activating CaMKII, possibly via inhibition of PP1.
Severe maternal morbidity due to abortion prospectively identified in a surveillance network in Brazil
Authors: Santana Danielly S. , Cecatti José G. , Parpinelli Mary A. , Haddad Samira M. , Costa Maria L. , Sousa Maria H. , Souza João P. , Camargo Rodrigo S. , Pacagnella Rodolfo C. , Surita Fernanda G. , Pinto e Silva João L. 
Published: July 2012

AbstractObjectiveTo evaluate the occurrence of severe maternal complications associated with abortion in Brazil.MethodsIn a cross‐sectional multicenter study, prospective surveillance was done for cases of potentially life‐threatening conditions (PLTC), maternal near miss (MNM), and maternal death (MD) among 9555 women with obstetric complications between June 2009 and May 2010. Abortion was evaluated as a cause, and sociodemographic and obstetric characteristics, safety conditions where the abortion was performed, and the medical procedures used were also assessed. Prevalence ratios adjusted for the cluster effect of the design were calculated with 95% confidence intervals. Multiple logistic regression analysis was performed to identify factors independently associated with greater severity.ResultsFor 237 women (2.5%), abortion resulted in severe complications including PLTC (81.9%), MNM (15.2%), and MD (3%). When abortion was unsafe, infectious causes were more common for PLTC, whereas management criteria were more important for MNM and MD. In multivariate analysis, the presence of previous maternal conditions (sickle cell disease, low weight, neoplasm), being transferred or referred, previous uterine scar, and delays were associated with greater severity.ConclusionAbortion was responsible for only a small percentage of the complications associated with pregnancy; however, the risk of abortion‐related complications progressing unfavorably was higher.
Description of Sarcocystis turdusi sp. nov. from the common blackbird (Turdus merula)
Authors: KUTKIENĖ L. , PRAKAS P. , BUTKAUSKAS D. , SRUOGA A. 
Published: July 2012

SUMMARYCysts of Sarcocystis species were found in 24 of 44 (54·5%) examined blackbirds (Turdus merula). Under the light microscope, only 1 morphological type of cyst was found in all birds investigated. Ribbon-shaped cysts were long (the largest fragment found amounted to 7 mm) and of different thickness (25–206 μm). A cyst wall reached up to 3·5 μm and had finger-like protrusions. Under the transmission electron microscope, a single cyst isolated from 1 blackbird was studied. The cyst wall was 2·5–4·4 μm thick, had club- or irregularly-shaped and sometimes branched protrusions that differed in size. The content of cysts was divided into large chambers by septa. Orange segment-shaped cystozoites were 6·2 × 1·4 (5·5–7·2 × 1·2–1·5) μm. This type of cyst wall has never been described in Sarcocystis species isolated from birds, thus far. The results of 18S rDNA, 28S rDNA and ITS–1 region sequences showed that S. turdusi was most closely related to S. columbae, S. calchasi, S. wobeseri, S. cornixi and Sarcocystis sp. ex Accipiter nisus parasitizing birds. Phylogenetic results suggest that predatory birds are the most probable definitive hosts of S. turdusi.