bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Functionalized Bicyclo[3.2.0]heptanes – a Study of the [2+2] Photocycloaddition Reactions of 4‐Hydroxycyclopent‐2‐enone Derivatives
Authors: Le Liepvre Matthieu , Ollivier Jean , Aitken David J. 
Published: October 2009

AbstractA selection of 4‐hydroxycyclopent‐2‐enone derivatives were prepared in enantiomerically pure form, and their photochemical [2+2] cycloaddition reactions with a variety of alkenes were studied, with a view to providing diversely functionalized bicyclo[3.2.0]heptanes. Intermolecular reactions provided the target structures in reasonable yields as a mixture of exo and endo adducts, in proportions which varied very little as a function of the steric bulk of the reactants or the reaction conditions. The system was suitably adapted for an intramolecular reaction, which provided a single, stereochemically pure product, the convenient precursor of a rigid, concave, trioxygenated skeleton. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Sterility testing by CE: A comparison of online preconcentration approaches in capillaries with greater internal diameters
Authors: Petr Jan , Jiang Chunxia , Sevcik Juraj , Tesarova Eva , Armstrong Daniel W. 
Published: October 2009

AbstractDetection of microbial contamination is of critical importance in the medical and the food industry. Rapid tests for the absence or presence of viable microorganisms are in urgent demand. CE is a modern analytical technique that can be adapted for rapid screening of microbial contamination. However, the small dimensions of capillaries allow the introduction of only a small fraction of the sample, which can be problematic when examining large samples. In this article, we examine the possibilities of introducing larger sample volumes using capillaries with greater id together with different stacking techniques. The use of 0.32 mm id capillary and the injection of 60% of the capillary volume led to approximately 120‐fold improvement of the injected sample volume over the classical injection 5% of a 0.10‐mm id capillary. The setup we described opens new possibilities in sterility testing using CE.
The interspecific relationships of Astragalus species in Egypt assessed by the morpho‐anatomical characters of the pod
Authors: Mourad M. M. , Sharawy S. M. 
Published: October 2009

AbstractThe pod morphological and anatomical characters of 20 species, one subspecies and five varieties of Astragalus out of the 32 species growing in Egypt were investigated by LM and SEM, and numerically analysed to show the inter‐ as well as the infra‐specific relationships. It was concluded that both A. trimestris and A. corrugatus show marked affinity to other species investigated in the present work. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Geranium jaramilloi (Geraniaceae), a new species from Colombia
Authors: Aedo C. 
Published: October 2009

AbstractA new species of Geranium L. (Geraniaceae), Geranium jaramilloi Aedo, sp. nova, is described and illustrated. The new species is morphologically most similar to G. santanderiense and G. lainzii. Geranium jaramilloi is easily distinguished by its leaves with entire segments (3‐lobed in G. santanderiense), and with abundant, patent, long and stout, eglandular hairs on both surfaces, although restricted to nerves abaxially (usually glabrous, and with a noticeable ciliate margin in G. santanderiense). Leaves also distinguished very well G. jaramilloi from G. lainzii, having the latter subtruncate leaves with 3‐lobed segments and scattered hairs near leaf margin. The new species belongs to sect. Gracilia, a group endemic to Colombia and Venezuela, characterized by its herbaceous and well developed stem, 2‐flowered cymules and inflorescence with dichasial branching. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hereditary gastrointestinal stromal tumors sharing the KIT Exon 17 germline mutation p.Asp820Tyr develop through different cytogenetic progression pathways
Authors: Veiga Isabel , Silva Mara , Vieira Joana , Pinto Carla , Pinheiro Manuela , Torres Lurdes , Soares Marta , Santos Lúcio , Duarte Hugo , Bastos Artur L. , Coutinho Camila , Dinis José , Lopes Carlos , Teixeira Manuel R. 
Published: October 2009

AbstractHereditary gastrointestinal stromal tumor (GIST) syndrome is a rare autosomal dominant genetic disorder originated by germline mutations in the KIT or PDGFRA genes. We report the third family with hereditary predisposition to GIST due to the KIT Exon 17 germline mutation p.Asp820Tyr and characterize the cytogenetic progression pathways followed by different GIST sharing the same primary genetic event, using a combination of chromosome banding, comparative genomic hybridization (CGH), and fluorescence in situ hybridization (FISH) analyses. The missense mutation p.Asp820Tyr was detected in the proband's rectal and gastric GIST, as well as in his aunt's GIST epiplon metastasis. The mutation p.Asp820Tyr was subsequently also found in the proband's peripheral blood DNA, as well as in that of 4 of 10 relatives thus far analyzed. CGH analysis revealed loss of 14q and 15q in the proband's gastric lesion, whereas FISH analysis of the proband's rectal GIST did not detect loss of 14q and 15q, but instead loss of 4q and 22q and gain of 20q, indicating that the two tumors were independent GIST. Chromosome banding and CGH analyses of the aunt's GIST epiplon metastasis revealed multiple cytogenetic alterations, including 1p loss, but none in common with the two proband's GIST. We conclude that, although the patients share the same KIT Exon 17 germline mutation, the multiple GIST analyzed followed different pathogenetic progression pathways, each of which did not significantly differ from what has been described in sporadic GIST. © 2009 Wiley‐Liss, Inc.
Genome‐wide scan identifies a copy number variable region at 3q26 that regulates PPM1L in APC mutation‐negative familial colorectal cancer patients
Authors: Thean L. F. , Loi C. , Ho K. S. , Koh P. K. , Eu K. W. , Cheah P. Y. 
Published: October 2009

AbstractFamilial adenomatous polyposis (FAP) is an autosomal dominantly inherited form of colorectal cancer (CRC) caused by mutation in the adenomatous polyposis coli (APC) gene. However, APC mutations are not detected in 10–50% of FAP patients. We searched for a new cancer gene by performing genome‐wide genotyping on members of an APC mutation‐negative FAP variant family and ethnicity‐matched healthy controls. No common copy number change was found in all affected members using the unaffected members and healthy controls as baseline. A 111 kb copy number variable (CNV) region at 3q26.1 was shown to have copy number loss in all eight polyps compared to matched lymphocytes of two affected members. A common region of loss in all polyps, which are precursors to CRC, is likely to harbor disease‐causing gene in accordance to Knudsen's “two‐hit” hypothesis. There is, however, no gene within the deleted region. A 2‐Mb scan of the genomic region encompassing the deleted region identified PPM1L, coding for a novel serine‐threonine phosphatase in the TGF‐β and BMP signaling pathways. Real‐time PCR analyses indicate that the 3′UTR of PPM1L transcript was down‐regulated more than two‐folds in all six polyps and tumors compared to matched mucosa of the affected member. This down‐regulation was not observed in APC mutation‐positive FAP patients. Our results suggest that the CNV region at 3q26 harbors an element that regulates the expression of an upstream candidate tumor suppressor, PPM1L, thus providing a novel mechanism for colorectal tumorigenesis in APC mutation‐negative familial CRC patients. © 2009 Wiley‐Liss, Inc.
In silico prediction and screening of γ‐secretase inhibitors by molecular descriptors and machine learning methods
Authors: Yang Xue‐Gang , Lv Wei , Chen Yu‐Zong , Xue Ying 
Published: October 2009

Abstractγ‐Secretase inhibitors have been explored for the prevention and treatment of Alzheimer's disease (AD). Methods for prediction and screening of γ‐secretase inhibitors are highly desired for facilitating the design of novel therapeutic agents against AD, especially when incomplete knowledge about the mechanism and three‐dimensional structure of γ‐secretase. We explored two machine learning methods, support vector machine (SVM) and random forest (RF), to develop models for predicting γ‐secretase inhibitors of diverse structures. Quantitative analysis of the receiver operating characteristic (ROC) curve was performed to further examine and optimize the models. Especially, the Youden index (YI) was initially introduced into the ROC curve of RF so as to obtain an optimal threshold of probability for prediction. The developed models were validated by an external testing set with the prediction accuracies of SVM and RF 96.48 and 98.83% for γ‐secretase inhibitors and 98.18 and 99.27% for noninhibitors, respectively. The different feature selection methods were used to extract the physicochemical features most relevant to γ‐secretase inhibition. To the best of our knowledge, the RF model developed in this work is the first model with a broad applicability domain, based on which the virtual screening of γ‐secretase inhibitors against the ZINC database was performed, resulting in 368 potential hit candidates. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Efficient nonbonded interactions for molecular dynamics on a graphics processing unit
Authors: Eastman Peter , Pande Vijay S. 
Published: October 2009

AbstractWe describe an algorithm for computing nonbonded interactions with cutoffs on a graphics processing unit. We have incorporated it into OpenMM, a library for performing molecular simulations on high‐performance computer architectures. We benchmark it on a variety of systems including boxes of water molecules, proteins in explicit solvent, a lipid bilayer, and proteins with implicit solvent. The results demonstrate that its performance scales linearly with the number of atoms over a wide range of system sizes, while being significantly faster than other published algorithms. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
Regulation of stemness and stem cell niche of mesenchymal stem cells: Implications in tumorigenesis and metastasis
Authors: Kuhn Nastaran Z. , Tuan Rocky S. 
Published: October 2009

AbstractHuman mesenchymal stem cells (MSCs) derived from adult tissues have been considered a candidate cell type for cell‐based tissue engineering and regenerative medicine. These multipotent cells have the ability to differentiate along several mesenchymal lineages and possibly along non‐mesenchymal lineages. MSCs possess considerable immunosuppressive properties that can influence the surrounding tissue positively during regeneration, but perhaps negatively towards the pathogenesis of cancer and metastasis. The balance between the naïve stem state and differentiation is highly dependent on the stem cell niche. Identification of stem cell niche components has helped to elucidate the mechanisms of stem cell maintenance and differentiation. Ultimately, the fate of stem cells is dictated by their microenvironment. In this review, we describe the identification and characterization of bone marrow‐derived MSCs, the properties of the bone marrow stem cell niche, and the possibility and likelihood of MSC involvement in cancer progression and metastasis. J. Cell. Physiol. 222: 268–277, 2010. © 2009 Wiley‐Liss, Inc.
Molecular mechanism underlying muscle mass retention in hibernating bats: Role of periodic arousal
Authors: Lee Kisoo , So Hyekyoung , Gwag Taesik , Ju Hyunwoo , Lee Ju‐Woon , Yamashita Masamichi , Choi Inho 
Published: October 2009

AbstractHibernators like bats show only marginal muscle atrophy during prolonged hibernation. The current study was designed to test the hypothesis that hibernators use periodic arousal to increase protein anabolism that compensates for the continuous muscle proteolysis during disuse. To test this hypothesis, we investigated the effects of 3‐month hibernation (HB) and 7‐day post‐arousal torpor (TP) followed by re‐arousal (RA) on signaling activities in the pectoral muscles of summer‐active (SA) and dormant Murina leucogaster bats. The bats did not lose muscle mass relative to body mass during the HB or TP‐to‐RA period. For the first 30‐min following arousal, the peak amplitude and frequency of electromyographic spikes increased 3.1‐ and 1.4‐fold, respectively, indicating massive myofiber recruitment and elevated motor signaling during shivering. Immunoblot analyses of whole‐tissue lysates revealed several principal outcomes: (1) for the 3‐month HB, the phosphorylation levels of Akt1 (p‐Akt1) and p‐mTOR decreased significantly compared to SA bats, but p‐FoxO1 levels remained unaltered; (2) for the TP‐to‐RA period, p‐Akt1 and p‐FoxO1 varied little, while p‐mTOR showed biphasic oscillation; (3) proteolytic signals (i.e., atrogin‐1, MuRF1, Skp2 and calpain‐1) remained constant during the HB and TP‐to‐RA period. These results suggest that the resistive properties of torpid bat muscle against atrophy might be attained primarily by relatively constant proteolysis in combination with oscillatory anabolic activity (e.g., p‐mTOR) corresponding to the frequency of arousals occurring throughout hibernation. J. Cell. Physiol. 222: 313–319, 2010. © 2009 Wiley‐Liss, Inc.
Antioxidant activity and properties of gelatin films incorporated with tea polyphenol‐loaded chitosan nanoparticles
Authors: Bao Shibao , Xu Shiying , Wang Zhang 
Published: October 2009

AbstractBACKGROUND: Gelatin film is widely used for the protection of food quality. In order to improve its antioxidant activity, natural antioxidant tea polyphenol‐loaded chitosan nanoparticles (TPCN) were prepared and incorporated into gelatin film. The antioxidant effect of TPCN against the oxidation of fish oil was investigated, as well as the release of TP from nanoparticles in the film.RESULTS: The incorporation of TPCN greatly decreased the tensile strength and oxygen permeability but increased the water vapour permeability and affected the transparency of gelatin film. Scanning electron microscopy images indicated that extensive interference was embedded with TPCN in the film microstructure. The peroxide value of fish oil packaged with films incorporated with TPCN was lower than that of fish oil packaged with control films during the incubation period. The radical‐scavenging activity of films incorporated with TPCN was higher than that of control films, and increasing radical‐scavenging activity of the former was observed during the storage period.CONCLUSION: The antioxidant activity and properties of gelatin film were affected by TPCN incorporation and storage time. Also, the oxidation of fish oil was retarded. The addition of TPCN could improve the antioxidant activity of gelatin film, and the release of TP from nanoparticles in the film was achieved during the storage period. Copyright © 2009 Society of Chemical Industry
Determination of polyphenolics in extracts of Potentilla species by high‐performance thin‐layer chromatography photodensitometry method
Authors: Tomczyk Michał , Bazylko Agnieszka , Staszewska Anna 
Published: October 2009

AbstractIntroduction – Separation of polyphenolics in different plant materials using high‐performance thin‐layer chromatography (HPTLC) represents an effective method for their detection and quantification.Objective – To develop a simple, specific, precise, sensitive and accurate method for the simultaneous quantification of tiliroside (TRS), methyl brevifolincarboxylate (MBR) and ellagic acid (EA) in a plant extract using the HPTLC‐photodensitometry method.Methodology – Aerial parts of the selected Potentilla species, P. anserina, P. erecta, P. grandiflora and P. nepalensis var. ‘Miss Willmott’, were extracted with methanol. After solvent evaporation, the methanolic extracts were diluted with water and successively partitioned between chloroform and then diethyl ether. The diethyl ether extracts from each sample were used for quantification. The analyses were performed on HPTLC precoated silica gel 60F254 plates with toluene–ethyl formate–formic acid (6 : 4 : 1 v/v/v) as the mobile phase (distance of 7.5 cm). Densitometric detections of TRS, MBR and EA were performed at 320, 287 and 280 nm, respectively. The amounts of these compounds were calculated using the regression equations of the calibration curves, which were linear within a range of 0.05–0.5 μg/spot (R2 = 0.9957) for TRS, 0.05–0.525 μg/spot (R2 = 0.9965) for MBR and 0.0525–0.5 μg/spot (R2 = 0.9998) for EA.Results – The amounts of marker compounds measured by the method developed are expressed in mg/g of dry extracts. TRS ranged from 20.3 ± 0.3 mg/g for P. erecta herbs to 197.7 ± 2.9 mg/g for P. grandiflora herbs; MBR ranged from 5.0 ± 0.6 mg/g for P. erecta herbs to 68.5 ± 3.4 mg/g for P. nepalensis flowers; and EA ranged from 24.0 ± 0.6 mg/g for P. erecta herbs to 216.2 ± 3.2 mg/g for P. anserina leaves.Conclusion – The proposed method was found to be relatively simple, specific, precise, sensitive and accurate and may be used for the routine assay of simultaneous determination of TRS, MBR and EA in other extracts and phytomedicines containing Potentilla species. Copyright © 2009 John Wiley & Sons, Ltd.
Types and treatment of pediatric sleep disturbances
Authors: Hamilton Gloria J. 
Published: October 2009

AbstractThis article provides an overview of pediatric sleep disturbances with emphases on types and treatments. Relationships between sleep disorders and comorbid conditions function to exacerbate and maintain both disorders. An estimated 20% of teenagers experience chronic partial sleep deprivation, resulting in problems with memory, attention, and behavior control. Treatment of choice for chronic partial sleep deprivation involves a comprehensive approach to regularizing the adolescent's sleep–wake schedule. The American Academy of Pediatrics (AAP) calls into question the validity of upward trends in prescribing for children and adolescents who report sleep problems. The AAP has issued a consensus statement on prescribing hypnotics to children and adolescents, arguing that further clinical trials are necessary to determine appropriate pediatric dosages. The AAP recommends that pediatricians educate families about good sleep practices and behavioral interventions. © 2009 Wiley Periodicals, Inc.
Mn configuration in III‐V semiconductors and its influence on electric transport and semiconductor magnetism
Authors: Wolos Agnieszka , Piersa Miroslaw , Strzelecka Grazyna , Korona Krzysztof P. , Hruban Andrzej , Kaminska Maria 
Published: October 2009

AbstractGaAs and GaP doped with Mn at wide range of concentrations were studied and compared to literature data of InP and nitrides, GaN and AlN, in aim to understand the mechanism of ferromagnetism observed in some of them. Doping with a moderate Mn concentrations resulted in similar features of electric transport in these compounds, that is p‐type conductivity in host crystal valence band activated with energy related to the ionization energy of Mn acceptor at high temperature and hopping conductance in Mn impurity band dominating at low temperatures. From the magnitude of hopping conductance it was possible to determine Mn configuration, which occurred to be Mn2+(d5) with a bound hole on it, with different localization radius decreasing systematically in a series from GaAs through InP down to GaP and achieving full localization resulting in Mn3+(d4) configuration in wide band gap nitrides, GaN and AlN. A critical concentration of Mn for metal‐insulator transition related to full overlap of Mn‐bound hole wave functions could be calculated as equal to 3.6 × 1020 cm–3 in GaAs, 2.5 × 1021 cm–3 in InP and 3.7 × 1022 cm–3 in GaP, where the latter one corresponds to above 100 at.%. Similarly to GaP, metal‐insulator transition for GaN and AlN doped with Mn cannot be achieved even for 100% of Mn concentration. In GaAs doped with Mn on the level of about 2.8 × 1019 cm–3 split Mn impurity band is formed. Conductivity in the band at this Mn concentration is characterized by high mobility, comparable in magnitude to the mobility in GaAs valence band. Ferromagnetism of GaAs with high Mn concentration (> 1.1 ‐ 1.6 at.%) occurs in samples being on the metallic side of metal‐insulator transition what means that a mediating center in ferromagnetic ordering of Mn centers is totally unlocalized hole. This mechanism is difficult to realize in other studied III‐V compounds because of higher localization of Mn‐bound holes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Distribution of relaxation times of relaxors: comparison with dipolar glasses
Authors: Banys Juras , Grigalaitis Robertas , Mikonis Andrejus , Macutkevic Jan , Keburis Povilas 
Published: October 2009

AbstractIn the present publication we report the results of dielectric spectroscopy investigations of two classes of materials – relaxor and dipolar glasses. As model relaxor was chosen (Pb1–xLax)(ZryTi1–y)O3 (PLZT 100(x/y/1–y)). The real distribution function of the relaxation times f (τ) of the relaxor ferroelectric ceramics PLZT 8/65/35 and 9.5/65/35 was calculated from the dielectric measurements results in the wide frequency range (101–1012 Hz). Below the Burns temperature TB ≅ 620 K, when the clusters begin to appear on cooling, the distribution function of the relaxation times is symmetrically shaped. On cooling the dispersion and loss spectra strongly broaden and slow down, the f (τ) function becomes asymmetrically shaped and the second maximum appears. The width of the f (τ) function was calculated at different temperatures. The longest relaxation times diverge according to the Vogel‐Fulcher law with the freezing temperature 299 K and 252 K for the 8/65/35 and 9.5/65/35 samples, respectively. The shortest relaxation time is about 10–12 s and it remains almost temperature independent. Similar behaviour was observed in dipolar glasses betaine phosphate betaine phosphite (BP/BPI). Much more information was obtained from two dimensional distribution of the relaxation times. This confirmed Meyer–Neldel law in relaxors and dipolar glasses. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computational insights into halogen bonding between PCl contact and several electron donors
Authors: Xu Lin , Zou Jian‐Wei , Yu Qing‐Sen , Sang Peng 
Published: October 2009

AbstractIn this work, computations of density functional theory (DFT) have been carried out to investigate the interactions between the PCl unit of hexachlorocyclotriphosphazene and several common electron donors. Such small systems are selected to explore the potential P‐bound halogen bonding interactions within polymeric structure and supramolecules. In all cases, the intermolecular distances are shown to be equal to or below sums of van der Waals radii of the atoms involved. Halogen bonding energies, calculated at B971/6‐311+G(d,p), span over a relatively lager range, from −0.95 to −95.30 kcal/mol, which intimate that the interactions are comparable to, or even partly prevail over, the conventional hydrogen bonding. For the charge‐assisted systems, calculations show that these systems can result in much stronger halogen bonding than the corresponding neutral ones. The results agree well with those of natural population analysis (NPA). Finally, the theory of atoms in molecules (AIM) was applied to provide more insight into the nature of these interactions. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010