bluuebunny/crossref_metadata_2025 huggingface dataset:
Case‐matching analysis of head and neck squamous cell carcinoma in racial and ethnic minorities in the United States—Possible role for human papillomavirus in survival disparities
Authors: Schrank Travis P. , Han Yimei , Weiss Heidi , Resto Vicente A.
Published: March 2010

Background.

Several studies have documented disparities in head and neck cancer outcomes for black patients in the United States. Recent studies have found that differences in oropharyngeal tumor human papillomavirus (HPV) status may be a cause of this disparity.

Methods.

In all, 76,817 cases of head and neck squamous cell carcinoma (HNSCC) recorded in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program were analyzed. Racial/ethnic groups were studied, for disease‐specific survival in both case‐matched and nonmatched cohorts. Calculation of expected disparity magnitudes based on HPV status was performed using data reported in the literature.

Results.

A disease‐specific survival disparity was demonstrated for Hispanic patients. However, case matching eliminated this disparity. Conversely, the disparity for black patients persisted in matched cohorts. The oropharyngeal subsite was found to be the dominant contributor to this disparity.

Conclusions.

The survival disparity for Hispanic patients in SEER with HNSCC is explained by differences in presentation and treatment. Also, HPV tumor status is likely a key determinant of the disparity for black patients. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
FGF‐2 abolishes the chondrogenic effect of combined BMP‐6 and TGF‐β in human adipose derived stem cells
Authors: Hildner Florian , Peterbauer Anja , Wolbank Susanne , Nürnberger Sylvia , Marlovits Stefan , Redl Heinz , van Griensven Martijn , Gabriel Christian
Published: March 2010

In this study, we investigated the influence of transforming growth factor beta 3 (TGF‐β3), bone morphogenetic protein 6 (BMP‐6) and basic fibroblast growth factor (FGF‐2) on chondrogenesis in adipose derived stem cells (ASC). Cells were isolated from liposuction material, expanded and subjected to chondrogenic differentiation. Micromass pellets were cultured in chondrogenic medium containing 10 ng/mL TGF‐β3 which was additionally supplemented with 10 ng/mL BMP‐6, 10 ng/mL FGF‐2 or a combination of both. We quantitatively evaluated the cartilage specific gene expression after 14 days of culture. The end point measurements on day 35 included glycosaminoglycan (GAG) quantification, histological staining for chondrogenic markers, and transmission electron microscopy (TEM). In comparison to cultures induced with TGF‐β3/FGF‐2, the presence of TGF‐β3/BMP‐6 demonstrated strong induction of collagen type II, collagen type IX and aggrecan mRNA expression. This was corroborated by quantification and histological staining for GAGs and immunohistological staining for collagen II. However, when a combination of BMP‐6 and FGF‐2 in addition to TGF‐β3 was added, FGF‐2 counteracted BMP‐6, as indicated by reduced marker gene expression and weak to absent staining for GAGs. In conclusion, this study demonstrates that BMP‐6 combined with TGF‐β3 is a potent inducer of chondrogenesis in human ASC. In contrast, FGF‐2 does not contribute to differentiation, but rather suppresses the chondrogenic potential of BMP‐6. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Enhanced osteoblastic activity and bone regeneration using surface‐modified porous bioactive glass scaffolds
Authors: Miguel Blanca San , Kriauciunas Rytis , Tosatti Samuele , Ehrbar Martin , Ghayor Chafik , Textor Marcus , Weber Franz E.
Published: March 2010

The potential use as a bone substitute material of a three‐dimensional bioactive glass fiber scaffold composed of Na2O‐K2O‐MgO‐CaO‐B2O3‐P2O5‐SiO2 (BG1) was investigated in this work. Scaffolds were pre‐treated with simulated body fluid (SBF) to promote the formation of two different bone‐like apatite layers on their surfaces. The topography and roughness of the deposited layers were assessed by scanning electron microscopy (SEM), while the chemical composition and structure using X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy, respectively. Based on surface analysis, the bioactive glass surfaces were ranked from smoothest to roughest: 0 SBF (untreated), 1× SBF and 2× SBF. A calcium‐deficient carbonated hydroxyapatite (HCA) layer was present on both SBF‐treated scaffolds, with higher number and larger bone‐like apatite nodule formation in the 2× SBF case. MC3T3‐E1 preosteoblasts showed a more flattened morphology and higher cell proliferation on the nontreated scaffolds; whereas, cells were more elongated and had higher osteoblastic activity on SBF‐treated samples. In vivo results in a rabbit calvarial bone defect model showed enhanced bone formation with SBF pretreated scaffolds, compared with untreated ones, commercially available Perioglass® particles and empty defects. Our findings demonstrate that the formation of a rough HCA layer on bioactive glass porous scaffolds enhanced preosteoblast maturation in vitro, as well as bone formation in vivo. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Comparison of morphology, orientation, and migration of tendon derived fibroblasts and bone marrow stromal cells on electrochemically aligned collagen constructs
Authors: Gurkan Umut Atakan , Cheng Xingguo , Kishore Vipuil , Uquillas Jorge Alfredo , Akkus Ozan
Published: March 2010

There are approximately 33 million injuries involving musculoskeletal tissues (including tendons and ligaments) every year in the United States. In certain cases the tendons and ligaments are damaged irreversibly and require replacements that possess the natural functional properties of these tissues. As a biomaterial, collagen has been a key ingredient in tissue engineering scaffolds. The application range of collagen in tissue engineering would be greatly broadened if the assembly process could be better controlled to facilitate the synthesis of dense, oriented tissue‐like constructs. An electrochemical method has recently been developed in our laboratory to form highly oriented and densely packed collagen bundles with mechanical strength approaching that of tendons. However, there is limited information whether this electrochemically aligned collagen bundle (ELAC) presents advantages over randomly oriented bundles in terms of cell response. Therefore, the current study aimed to assess the biocompatibility of the collagen bundles in vitro, and compare tendon‐derived fibroblasts (TDFs) and bone marrow stromal cells (MSCs) in terms of their ability to populate and migrate on the single and braided ELAC bundles. The results indicated that the ELAC was not cytotoxic; both cell types were able to populate and migrate on the ELAC bundles more efficiently than that observed for random collagen bundles. The braided ELAC constructs were efficiently populated by both TDFs and MSCs in vitro. Therefore, both TDFs and MSCs can be used with the ELAC bundles for tissue engineering purposes. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010
Combination of enzymes and flow perfusion conditions improves osteogenic differentiation of bone marrow stromal cells cultured upon starch/poly(ε‐caprolactone) fiber meshes
Authors: Martins Ana M. , Saraf Anita , Sousa Rui A. , Alves Catarina M. , Mikos Antonios G. , Kasper F. Kurtis , Reis Rui L.
Published: March 2010

Previous studies have shown that α‐amylase and lipase are capable of enhancing the degradation of fiber meshes blends of starch and poly(ε‐caprolactone) (SPCL) under dynamic conditions, and consequently to promote the proliferation and osteogenic differentiation of bone marrow stromal cells (MSCs). This study investigated the effect of flow perfusion bioreactor culture in combination with enzymes on the osteogenic differentiation of MSCs. SPCL fiber meshes were seeded with MSCs and cultured with osteogenic medium supplemented with α‐amylase, lipase, or a combination of the two for 8 or 16 days using static or flow conditions. Lipase and its combination with α‐amylase enhanced cell proliferation after 16 days. In addition, the flow perfusion culture enhanced the infiltration of cells and facilitated greater distribution of extracellular matrix (ECM) throughout the scaffolds in the presence/absence of enzymes. A significant amount of calcium was detected after 16 days in all groups cultured in flow conditions compared with static cultures. Nevertheless, when α‐amylase and lipase were included in the flow perfusion cultures, the calcium content was 379 ± 30 μg/scaffold after as few as 8 days. The highest calcium content (1271 ± 32 μg/scaffold) was obtained for SPCL/cell constructs cultured for 16 days in the presence of lipase and flow. Furthermore, von Kossa staining and tetracycline fluorescence of histological sections demonstrated mineral deposition within the scaffolds for all groups cultured for 16 days under flow. However, all the data corroborate that lipase coupled with flow perfusion conditions improve the osteogenic differentiation of MSCs and enhance ECM mineralization. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
A perspective on MALDI alternatives—total solvent‐free analysis and electron transfer dissociation of highly charged ions by laserspray ionization
Authors: Trimpin Sarah
Published: March 2010

Progress in research is hindered by analytical limitations, especially in biological areas in which sensitivity and dynamic range are critical to success. Inherent difficulties of characterization associated with complexity arising from heterogeneity of various materials including topologies (isomeric composition) and insolubility also limit progress. For this reason, we are developing methods for total solvent‐free analysis by mass spectrometry consisting of solvent‐free ionization followed by solvent‐free gas‐phase separation. We also recently constructed a novel matrix‐assisted laser desorption ionization (MALDI) source that provides a simple, practical and sensitive way of producing highly charged ions by laserspray ionization (LSI) or singly charged ions commonly observed with MALDI by choice of matrix or matrix preparation. This is the first ionization source with such freedom—an extremely powerful analytical ‘switch’. Multiply charged LSI ions allow molecules exceeding the mass‐to‐charge range of the instrument to be observed and permit for the first time electron transfer dissociation fragment ion analysis. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of land use changes on local meteorological conditions in Jakarta, Indonesia: toward the evaluation of the thermal environment of megacities in Asia
Authors: Tokairin Takayuki , Sofyan Asep , Kitada Toshihiro
Published: March 2010

In the past few decades, the surroundings of the initially urbanised area (the old city) of Jakarta, Indonesia, was rapidly urbanised and the daily mean air temperature increased by approximately 1 K. Accordingly, the effect of the land use change in the area of Jakarta on the local climate was investigated using a mesoscale meteorological model. After model performance was validated against observational data, the model was run to simulate the meteorological field over the city for the dry season. In the simulations, three cases were considered: (1) the land use in the present day, (2) the land use in the 1970s, and (3) land use with no urban areas. The simulations led to the following findings. First, the sea breeze developed at an earlier time of day in the present day than in the 1970s. Second, in the present‐day case, a converging flow developed over the old city in association with the low pressure which formed over the same location. Third, the daytime average and maximum air temperature in the old city were higher in the present day than in the 1970s by 0.6 and 0.9 K, respectively, due to the advection of heat from the new urban area. Finally, the amount of heat advected into the old city was estimated to be − 0.7 Wm−2 in the 1970s and 77 Wm−2 in the 2000s. The estimated value in the 2000s case was 44% of the magnitude of the sensible heat flux from the ground surface into the atmosphere. Copyright © 2010 Royal Meteorological Society
The impact of crime victimization on quality of life
Authors: Hanson Rochelle F. , Sawyer Genelle K. , Begle Angela M. , Hubel Grace S.
Published: March 2010

The authors review the extant literature examining the functional impact of crime victimization on indices of quality of life. They present findings within a conceptual framework comprised of role functioning, life satisfaction, and well‐being, and social–material conditions, including crime‐related medical, mental health, and employer costs, and health care utilization. The review indicates that crime victimization impacts multiple domains, including parenting skills, impaired occupational functioning, higher rates of unemployment, and problematic intimate relationships. However, data on relationships between crime victimization and overall life satisfaction were mixed, suggesting the need for further investigation. The authors conclude with a brief discussion of directions for future research.
Differences in changes in health‐related anxiety between Western and non‐Western participants in a trauma‐focused study
Authors: Verschuur Margot J. , Maric Marija , Spinhoven Philip
Published: March 2010

Disaster victims from ethnic minorities manifest more health complaints and concerns than others following a medical investigation. The authors aimed at analyzing ethnicity as a proxy for risk factors predictive of changes in health‐related anxiety, and mediators that explain ethnic group differences after participating in a medical investigation. Western (n = 406) and non‐Western participants (n = 379) were assessed at baseline and 12‐week follow‐up. Education, unemployment, years of residence, and posttraumatic stress disorder symptoms were independent predictors of changes in health‐related anxiety, excluding ethnicity. The predictive value of ethnicity was mediated mainly by changes in psychopathology, fatigue, and quality of life. Stronger responses to a trauma‐related investigation by more vulnerable ethnic minority groups may explain their enhanced health‐related anxiety.
Bushfire impact on youth
Authors: Yelland C. , Robinson P. , Lock C. , La Greca A. M. , Kokegei B. , Ridgway V. , Lai B.
Published: March 2010

The authors examined the association between disaster‐related traumatic experiences and posttraumatic stress disorder (PTSD) symptoms in 155 youth, aged 8–18 years, from the Lower Eyre Peninsula of South Australia who were affected by January 2005 bushfires. Youth completed measures of PTSD symptoms and disaster experiences 11–5 months postdisaster. Many youth (27%) reported moderate to severe levels of PTSD symptoms; younger children reported greater PTSD symptom severity than older youth. Perceived personal life threat and ongoing loss/disruption were related to greater PTSD symptomatology. Following disasters, it may be helpful to identify young children and youth who perceived that their life was threatened and experienced more ongoing life disruption, as these youth may be at higher risk for persistent PTSD symptoms.
Shear Dynamic Moduli of Stretched Polymer Chains and Networks: Modified Rouse Model
Authors: Toshchevikov Vladimir P. , Heinrich Gert , Gotlib Yulii Ya.
Published: March 2010

The dynamic mechanical properties of polymer chains and networks under large static strains are studied. Polymer chains are modeled as sequences of Gaussian subchains whose elasticity constants are different for motions parallel ($K_{||} $) and perpendicular ($K_ \bot $) to the stretching force, f, and are functions of the elongation ratio (a modified Rouse model). The frequency‐dependent storage and loss shear moduli are shown to be different for different geometries under small oscillating shear deformation. Three principal geometries under shear deformation denoted by D‐, V‐ and G‐geometry (see the image) are considered. Static elongation leads to the broadening of the frequency dependencies of the loss moduli for all considered geometries. The predicted storage and loss moduli are in a good agreement with experimental data.

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Epigenetic silencing of cell cycle regulatory genes during 3‐methylcholanthrene and diethylnitrosamine‐induced multistep rat lung cancer
Authors: Liu Wen‐Bin , Liu Jin‐Yi , Ao Lin , Zhou Zi‐Yuan , Zhou Yan‐Hong , Cui Zhi‐Hong , Cao Jia
Published: March 2010

The rat lung cancers induced by 3‐methylcholanthrene (MCA) and diethylnitrosamine (DEN) are considered to be a good model for illustrating genetic alterations in human lung precancerous and cancerous lesions. Recently, we had reported that the model can also be used to investigate the step‐by‐step dynamic changes in DNA methylation during lung carcinogenesis. In this study, we have used the same animal model to further study the evolution of methylation alterations of cell cycle regulatory genes CDKN1B (p27) and CDKN1C (p57). Our results showed epigenetic alterations in p27 and p57. Promoter hypermethylation of p27 was detected in one sample of carcinoma in situ (CIS) and two samples of infiltrating carcinoma, all three of which lacked expression of the p27 protein. Methylation of the p57 promoter correlated with the loss of protein expression in lung pathologic lesions, with a gradual increase in methylation frequency from 0 sample in the normal epithelium and hyperplasia, to 11.1% in squamous metaplasia, 18.9% in dysplasia, 26.7% in CIS, and finally 36.0% in infiltrating carcinoma samples. Immunohistochemical analysis showed that p27 and p57 protein expression decreased as lung carcinogenesis progressed. Moreover, weak expression of p27 and p57 in methylated primary tumor cell lines increased markedly after treatment with 5‐aza‐2′‐deoxycytidine (5‐aza‐dC), confirming that methylation was indeed responsible for the gene downregulation. These results suggest that the progression of rat lung carcinogenesis induced by MCA/DEN is associated with dynamic changes in promoter hypermethylation of cell cycle regulatory genes, including p27 and p57, accounting for their defective expression. © 2010 Wiley‐Liss, Inc.
Investigation of an adaptive sampling method for data interpolation using radial basis functions
Authors: Mackman T. J. , Allen C. B.
Published: March 2010

An adaptive sampling method is presented for optimizing the location of data points in parameter space for multidimensional data interpolation. The method requires a small number of points to begin, and achieves a compromise between space‐filling updates and local refinement in areas where the data are nonlinear, as measured by the Laplacian. A smooth separation function quantifies the sample spacing, and this is blended with the Laplacian to form a criterion on which to assess potential new sample positions. Validation results are presented using two‐dimensional analytic test cases, which demonstrate that the method can recover known optimal designs and gives improvement over data‐independent approaches. In addition, a detailed analysis of the various model parameters is presented. Initial findings are very promising, and it is hoped that further work using the method to generate an aerodynamic database using CFD simulations will lead to a reduction in the number of points required for a given modelling accuracy. Copyright © 2010 John Wiley & Sons, Ltd.
Non‐specific indicators of stress and their association with age at death in Medieval York: Using stature and vertebral neural canal size to examine the effects of stress occurring during different periods of development
Authors: Watts R.
Published: March 2010

Selective mortality can occur towards individuals who survive episodes of physiological stress, such as disease and malnutrition, during development. The skeletal elements affected depend on the timing of these stressful episodes. Studying multiple non‐specific indicators of stress can show which periods of development were affected and whether certain periods can be linked with selective mortality. To examine this method a preliminary study of 61 adult individuals from the Medieval population of Fishergate House, York was undertaken to examine small vertebral neural canal size and reduced adult stature. Previous studies have shown that selective mortality occurs towards individuals who display these non‐specific indicators of stress. Statistical analysis showed that small transverse neural canal diameter was significantly associated with early adult mortality for males and females and there was evidence of selective mortality towards females with reduced stature. This suggests that individuals who died in early adulthood experienced health insults during late childhood which stunted VNC growth but males in particular were not significantly affected by health insults after this age as they achieved a normal adult stature. Therefore it appears that health insults which occurred during late childhood had a greater influence on adult health in the Fishergate House population. This method could be expanded to provide more detailed information by using a greater variety of non‐specific indicators of stress which will allow more specific periods of development to be investigated. Copyright © 2010 John Wiley & Sons, Ltd.
Osteosarcoma in children 5 years of age or younger at initial diagnosis
Authors: Worch Jennifer , Matthay Katherine K. , Neuhaus John , Goldsby Robert , DuBois Steven G.
Published: March 2010

Background

Since osteosarcoma is extremely rare in children ≤5 years of age, we sought to investigate if tumor characteristics, treatment strategies, and outcomes differ compared to older patients.

Procedure

Patients <20 years of age with high‐grade osteosarcoma reported to national SEER database from 1973 to 2006 were separated into two groups based on age at diagnosis: ≤5 years (n = 49) and 6–19 years (n = 1,687). Patient, tumor, and treatment characteristics were compared using Fisher exact tests. Overall survival was estimated by Kaplan–Meier methods and compared using log‐rank tests and Cox models.

Results

Patients ≤5 years had higher proportions of osteosarcoma arising from the upper limb compared to older patients (24.5% vs. 11.2%; P = 0.006). These very young patients had a significantly higher proportion of telangiectatic histology (10.2% vs. 2.9%; P = 0.017). Sex, metastatic status, race, or ethnicity did not differ by age. A higher proportion of very young patients was treated with amputation (55.2% vs. 27.3%; P = 0.002). Five‐year overall survival was inferior for patients with localized osteosarcoma 5 years of age or younger compared to older children (51.9% vs. 67.3%; P = 0.03). After controlling for metastatic status, year of diagnosis, and tumor site, the hazard ratio for death in very young patients was 1.6 (95% confidence interval 1.02–2.36; P = 0.04) compared to older patients.

Conclusions

Tumor characteristics, treatment, and outcomes differ among children ≤5 years of age compared to older pediatric patients. These differences may reflect differences in tumor biology. Pediatr Blood Cancer. 2010;55:285–289. © 2010 Wiley–Liss, Inc.
Predictors for neonatal thrombocytopenia in infants of thrombocytopenic mothers during pregnancy
Authors: Maayan‐Metzger Ayala , Leibovitch Lea , Schushan‐Eisen Irit , Strauss Tzipora , Kenet Gili , Kuint Jacob
Published: March 2010

Background

Although maternal thrombocytopenia during pregnancy is common, its effect on neonatal platelets has not yet been fully evaluated.

Methods

We retrospectively evaluated the rate of thrombocytopenia among 767 healthy term neonates (gestational age 37–42 weeks) born to 723 mothers with pregnancy‐induced thrombocytopenia to define risk factors predicting thrombocytopenia in this group.

Results

Thrombocytopenia was diagnosed in 2.2% of the infants. Multivariate analysis showed that infants with thrombocytopenia were more likely to be male, to be born at lower gestational age and to have lower birth weight associated with lower maternal platelets counts. Maternal platelet counts of 100–149 × 109/L, 50–99 × 109/L, and <50 × 109/L corresponded respectively to 1.7%, 4.3%, and 12.5% of neonatal thrombocytopenia (P = 0.031).

Conclusions

Routine blood counts are recommended, in particular for male infants with low birth weight born to mothers with moderate‐to‐severe thrombocytopenia. Pediatr Blood Cancer 2010;55:145–148. © 2010 Wiley‐Liss, Inc.
Thiol versus Selenol SAMs as Nucleation Enhancers and Adhesion Promoters for Plasma Polymerized Pyrrole on Copper Substrates
Authors: Yagüe José Luis , Agulló Núria , Fonder Gregory , Delhalle Joseph , Mekhalif Zineb , Borrós Salvador
Published: March 2010

The use of SAMs to enhance the deposition and growth of polypyrrole (PPy) thin films on a copper substrate by plasma‐enhanced chemical vapor deposition (PECVD) is described. The composition, ordering, and compactness of the monolayers is studied by XPS, PM‐IRRAS, and electrochemical techniques in order to determine their quality. Pyrrole plasma polymerization is carried out on SAMs and on bare copper to study the effect of the monolayer in the deposition process. AFM microscopy demonstrates that, because of the pyrrole‐terminated group, PPy nuclei deposit and grow preferably on the SAM‐modified surface. The PPy films deposited on SAMs show very good adhesion to a copper substrate, which makes them good candidates for new electronic components.

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Structural and functional characterization of CcmG from Pseudomonas aeruginosa, a key component of the bacterial cytochrome c maturation apparatus
Authors: Matteo Adele Di , Calosci Nicoletta , Gianni Stefano , Jemth Per , Brunori Maurizio , Travaglini‐Allocatelli Carlo
Published: March 2010

The cytochrome c maturation process is carried out in the bacterial periplasm, where some specialized thiol‐disulfide oxidoreductases work in close synergy for the correct reduction of oxidized apocytochrome before covalent heme attachment. We present a structural and functional characterization of the soluble periplasmic domain of CcmG from the opportunistic pathogen P. aeruginosa (Pa‐CcmG), a component of the protein machinery involved in cyt c maturation in gram‐negative bacteria. X‐ray crystallography reveals that Pa‐CcmG is a TRX‐like protein; high‐resolution crystal structures show that the oxidized and the reduced forms of the enzyme are identical except for the active‐site disulfide. The standard redox potential was calculated to be E0′ = −0.213 V at pH 7.0; the pKa of the active site thiols were pKa = 6.13 ± 0.05 for the N‐terminal Cys74 and pKa = 10.5 ± 0.17 for the C‐terminal Cys77. Experiments were carried out to characterize and isolate the mixed disulfide complex between Pa‐CcmG and Pa‐CcmH (the other redox active component of System I in P. aeruginosa). Our data indicate that the target disulfide of this TRX‐like protein is not the intramolecular disulfide of oxidized Pa‐CcmH, but the intermolecular disulfide formed between Cys28 of Pa‐CcmH and DTNB used for the in vitro experiments. This observation suggests that, in vivo, the physiological substrate of Pa‐CcmG may be the mixed‐disulfide complex between Pa‐CcmH and apo‐cyt. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Molecular dynamics simulation of SRP GTPases: Towards an understanding of the complex formation from equilibrium fluctuations
Authors: Yang Mingjun , Zhang Xin , Han Keli
Published: March 2010

Signal recognition particle (SRP) and its receptor (SR) play essential role in the SRP‐dependent protein targeting pathway. They interact with one another to precisely regulate the targeting reaction. The mechanism of this interaction consists of at least two discrete conformational states: complex formation and GTPase activation. Although structural studies have provided valuable insights into the understanding of the SRP‐SR interaction, it still remains unclear that how SRP and SR GTPases use their intrinsic conformational flexibilities to exert multiple allosteric regulations on this interaction process. Here, we use computational simulations to present the dynamic behavior of the SRP GTPases at an atomic level to gain further understanding of SRP‐SR interaction. We show that: (i) equilibrium conformational fluctuations contain a cooperative inter‐ and intradomain structural rearrangements that are functionally relevant to complex formation, (ii) a series of residues in different domains are identified to correlate with each other during conformational rearrangements, and (iii) α3 and α4 helices at domain interface actively rearrange their relative conformation to function as a bridge between the N domain and the core region of the G domain. These results, in addition to structural studies, would harness our understanding of the molecular mechanism for SRP and SR interaction. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Chemical tools in chromatin research
Authors: Schwarzer Dirk
Published: March 2010

Eukaryotes organize their DNA in the form of chromatin. This complex of DNA and packaging proteins, the histones, ensures that all genomic information fits into the limited space of the cell nucleus. In addition to compacting DNA, chromatin itself regulates the activity of encoded genes. This regulatory process involves many posttranslational modifications of histone proteins and deciphering the complex crosstalk between histone modifications and gene activity represents a central challenge for biomedical science. This task has often been supported by sophisticated chemical tools, which were crucial for many important discoveries in this field. This review provides an overview of chemical tools for chromatin research, with emphasis on classical and current examples of their applications. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Effect of the barrier width on the cathodoluminescence spectra in the strained CdTe/ZnTe superlattices with quantum dot layers
Authors: Kucherenko I. V. , Vinogradov V. S. , Trushin A. S. , Karczewski G.
Published: March 2010

The influence of the ZnTe barrier width on the cathodoluminescence (CL) spectra of the CdTe/ZnTe superlattices (SL) with CdTe quantum dots (QD) is studied. For the samples with the barrier width of 100, 50 and 25 ml CL spectra consist only of a single band with maximum at E = 2.03‐2.01 eV at 80 K. We assign this band to the emission from QD ensemble. For the samples with 10 ml barrier width the emission band splits into two lines of different intensity with maxima at E = 2.01 and 1.95 eV. However the emission spectrum of SL with 5 ml barrier width consists also of only one band with maximum at E = 1.92 eV. We explain these results by the influence of biaxial strain, resulting from the lattice mismatch, on the ground state of the heavy‐hole and light‐hole subbands in CdTe and ZnTe layers. For the CdTe/ZnTe SL with the deposited CdTe layer thickness of 1.5 ml we observed equidistant lines in QD and wetting layer emission bands separated by CdTe 2LO phonon energy (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of Zn0.95‐xBex Mn0.05Se mixed crystals by photoluminescence and contactless electroreflectance
Authors: Dumcenco Dumitru , Huang Chen‐Tai , Huang Ying‐Sheng , Firszt Franciszek , Łęgowski Stanislaw , Męczyńska Hanna , Zakrzewski Jacek , Tiong Kwong‐Kau
Published: March 2010

Temperature‐dependent photoluminescence (PL) and contactless electroreflectance (CER) measurements of Zn0.95‐xBexMn0.05Se mixed crystals with different Be content (0 ≤ x ≤ 0.26) grown by the modified high pressure Bridgman method has been carried out in the temperature range 15–300 K. The peak positions of band‐edge exciton features in the PL spectra are slightly shifted towards lower energies as compared to the corresponding transition energies obtained from CER data. The observed increases of the CER‐PL shift with the increasing of Be content are explained by the increasing compositional disorder causing the smearing of the band‐edge energies. The excitonic line broadening for the samples with larger Be/Zn ratio are attributed in part to the alloy scattering effects and also to the poorer crystalline quality of the samples with higher content of Be. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MOVPE growth and study of ZnO, ZnMgO epilayers and ZnO/ZnMgO MQW structures
Authors: Kuznetsov Petr , Lusanov Valery , Yakushcheva Galina , Jitov Victor , Zakharov Leonid , Kotelyanskii Iosif , Kozlovsky Vladimir
Published: March 2010

Due to large exciton binding energy, ZnO/ZnMgO heterostructures are promising for modern optoelectronic devices in UV range. We report on the metal‐organic vapor phase epitaxy (MOVPE) growth of ZnO, ZnMgO layers and periodic ZnO/ZnMgO MQW structures at atmospheric pressure of hydrogen using diethylzinc (DEZ), bismethyl‐cyclopentadienil‐magnesium ((MeCp)2Mg) and tertiary‐butanol (t‐BuOH) as precursors. Wurtzite‐type layers and MQW structures were grown below 450°C on Al2O3(0001) substrates. The growth rate is constant in the temperature interval from 170 to 430°C and decreases abruptly above 430°C as a result of decomposition in hydrogen. X‐ray measurement confirms the wurtzite structure of ZnMgO films with the Mg content of up to 35%. The as‐grown films show good optical quality and near band edge emission in the photoluminescence (PL) and cathodoluminescence (CL). Periodic ZnO/ZnMgO MQW structures with strong ZnO QWs emission at room temperature were grown. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of ZnO, Zn0.99Mn0.01O nanopowders
Authors: Sokolov V. I. , Yermakov A. Ye. , Uimin M. A. , Mysik A. A. , Pustovarov V. A. , Gruzdev N. B. , Surikov V. T.
Published: March 2010

The photoluminescence and photoluminescence excitation spectra of Zn0.99Mn0.01O nanopowders are presented in this paper. Detected peaks at energies ħω higher than the energy gap in the photoluminescence excitation spectra allow us to assume that the Zhang‐Rice‐like states in forbidden gap due to the strong exchange coupling between 3d localized spin and valence band holes are related with valence band states perturbed by strong p‐d hybridization (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO nanorods growth on sapphire substrates using aqueous solution with microwave heating and their photoluminescence properties
Authors: Ogata Ken‐ichi , Dobashi Hideaki , Koike Kazuto , Sasa Shigehiko , Inoue Masataka , Yano Mitsuaki
Published: March 2010

ZnO nanorods were grown on a ‐, c ‐ and r ‐plane sapphire substrates using aqueous solution with microwave irradiation heating. ZnO nanorods about 200 nm diameter with c‐axis orientation were grown independently on the orientation of the substrates. Photoluminescence (PL) spectrum at 6 K showed a dominant peak at 3.3609 eV (I6) with the width as narrow as 2.2 meV comparable to that of epitaxially grown single‐crystalline ZnO films. The PL properties were improved by thermal annealing process without generating structural defects. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigation of influence of accelerated rotating wave on solid‐liquid interface in CdZnTe ACRT crystal growth
Authors: Zhou Chenying , Min Jiahua , Wang Changjun , Liang Xiaoyan , Teng Jianyong , Wang Linjun
Published: March 2010

Process of CdZnTe crystal growth with vertical and low pressure Bridgman method (VLPB) was simulated by the software of Comsol Multiphysics. The accelerated crucible rotation technique (ACRT) in VLPB was studied. The simulation results showed that, in trapezoidal accelerated rotating wave, the solid‐liquid interface was appreciably convex and smooth. Meanwhile, the crystal growth rate was also a little greater than crucible dropping rate (1 mm/h), which kept the crystal grow up spontaneously and improved material crystallizability, crystal growth rate and quality (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical spin orientation of a single manganese atom
Authors: Le Gall C. , Kolodka R. , Besombes L. , Boukari H. , Cibert J. , Ferrand D. , Mariette H.
Published: March 2010

An optical spin orientation is achieved for a Mn atom localized in a semiconductor quantum dot using quasiresonant excitation at zero magnetic field. Optically created spin polarized carriers generate an energy splitting of the Mn spin and enable magnetic moment orientation controlled by the photon helicity and energy.

The dynamics and the magnetic field dependence of the optical pumping mechanism shows that the spin lifetime of an isolated Mn atom at zero magnetic field is controlled by a magnetic anisotropy induced by the built‐in strain in the quantum dots. Relaxation times exceeding the micro‐second range are measured (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of ZnSe semiconductor nanodot arrays by templated PVD
Authors: Valeev Rishat , Romanov Eduard , Deev Andrew , Beltukov Artemiy , Napolski Kirill , Eliseev Andrei , Krylov Petr , Mezentsev Nikolai , Kriventsov Vladimir
Published: March 2010

Here we report a novel approach for preparation of ZnSe nanodot arrays by physical vapor deposition on porous aluminum oxide templates possessing ordered system of channels. The structure of nanodot arrays was investigated by scanning electron microscopy and EXAFS‐spectroscopy. The geometry of nanodots and local atomic structure parameters like the interatomic distances and coordination numbers of Zn and Se atoms are reported. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EWMA control charts for monitoring binary processes with applications to medical diagnosis data
Authors: Weiß Christian H. , Atzmüller Martin
Published: March 2010

To monitor a binary process, exponentially weighted moving average (EWMA) control charts in different variations are proposed. The average run length performance of the EWMA approach both with standard and with skewness‐corrected 3‐σ control limits is investigated and design recommendations are derived. The proposed EWMA control charts are applied to medical diagnosis data taken from the diagnostic expert system SONOCONSULT in order to provide a semi‐automatic component for monitoring the documentation behavior of different examiners. Copyright © 2010 John Wiley & Sons, Ltd.
Application of AFM in microbiology: a review
Authors: Liu Shaoyang , Wang Yifen
Published: March 2010

Atomic force microscopy (AFM) is a powerful tool for microbiological investigation. This versatile technique cannot only image cellular surfaces at high resolution, but also measure many forms of fundamental interactions over scales ranging from molecules to cells. In this work, we review the recent development of AFM applications in the microbial area. We discuss several approaches for using AFM scanning images to investigate morphological characteristics of microbes and the use of force–distance curves to investigate interaction of microbial samples at the nanometer and cellular levels. Complementary techniques used in combination with AFM for study of microbes are also discussed. SCANNING 32: 61–73, 2010. © 2010 Wiley Periodicals, Inc.
Self‐leveling two‐dimensional probe arrays for Dip Pen Nanolithography®
Authors: Haaheim Jason , Val Vadim , Bussan John , Rozhok Sergey , Jang Jae‐Won , Fragala Joe , Nelson Mike
Published: March 2010

Scanning probe lithography (SPL) has witnessed a dramatic transformation with the advent of two‐dimensional (2D) probe arrays. Although early work with single probes was justifiably assessed as being too slow to practically apply in a nanomanufacturing context, we have recently demonstrated throughputs up to 3×107 µm2/h—in some cases exceeding e‐beam lithography—using centimeter square arrays of 55,000 tips tailored for Dip Pen Nanolithography® (DPN®). Parallelizing DPN has been critical because there exists a need for a lithographic process that is not only high throughput, but also high resolution (DPN has shown line widths down to 14 nm) with massive multiplexing capabilities. Although previous methods required non‐trivial user manipulation to bring the 2D array level to the substrate, we now demonstrate a self‐leveling fixture for NanoInk's 2D nano PrintArray. When mounted on NanoInk's NLP 2000, the 55,000 tip array can achieve a planarity of <0.1° with respect to the substrate in a matter of seconds, with no user manipulation required. Additional fine‐leveling routines (<2min of user interaction) can improve this planarity to <0.002° with respect to the substrate—a Z‐difference of less than 600 nm across 1 cm2 of surface area. We herein show highly homogeneous etch‐resist nanostructure results patterned from a self‐leveled array of DPN pens, with feature size standard deviation of <6% across a centimeter square sample. We illustrate the mechanisms and methods of the self‐leveling fixture, and detail the advantages thereof. Finally, we emphasize that this methodology brings us closer to the goal of true nanomanufacturing by automating the leveling process, reducing setup time by at least a factor of 10, enhancing the ease of the overall printing process, and ultimately ensuring a more level device with subsequently homogeneous nanostructures. SCANNING 32: 49–59, 2010. © 2010 Wiley Periodicals, Inc.
Total synthesis of (+)‐vinblastine: Control of the stereochemistry at C18′
Authors: Yokoshima Satoshi , Tokuyama Hidetoshi , Fukuyama Tohru
Published: March 2010

Vinblastine has been widely known as a prominent agent in cancer chemotherapy, and in order to search for more potent drugs, various analogs have been derived from natural products. However, because modifications of natural products have limited classes of derivatives, an efficient synthetic route toward vinblastine has been required.

Herein a stereocontrolled total synthesis of (+)‐vinblastine is described. The synthesis of the upper half features a stereoselective construction of the tertiary alcohol through a 1,3‐dipolar cycloaddition of nitrile oxide and a Baeyer‐Villiger oxidation, a facile indole formation utilizing a radical cyclization of o‐alkenylthioanilide, and a macrocyclization of 2‐nitrobenzenesulfonamide. The crucial coupling of the upper half with synthetic vindoline was successfully performed to furnish the coupling product in nearly quantitative yield, and subsequent transformations provided (+)‐vinblastine. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 101–118; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.200900025
Hydrothermal Syntheses and Crystal Structures of Two New Three‐dimensional Coordination Polymers Based on 4‐Pyrid‐3‐ylbenzoic Acid
Authors: Guo Feng
Published: March 2010

Two new coordination polymers [Co2(pbc)4(H2O)]n (1) and [Mn(pbc)2] (2) (Hpbc = 4‐pyrid‐3‐ylbenzoic acid) were obtained by hydrothermal reaction and characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. Compound 1 features a 3D network with a four‐connected 66 net constructed from secondary building units of dinuclear cobalt. Compound 2 exhibits a six‐connected 412·63 topology based on dinuclear manganese.
Crystalline and Glassy Phases in the Ternary System Tl/Bi/Cl: Synthesis and Crystal Structures of the Thallium(I) Chloridobismutates(III) Tl3BiCl6 and TlBi2Cl7
Authors: Beck Johannes , Benz Sebastian
Published: March 2010

Slow cooling of melts composed of TlCl and BiCl3 allows for the isolation of the compounds Tl3BiCl6 (1) and TlBi2Cl7 (2). Compound 1 is formed by sublimation at 480 °C from the black melt of 3 TlCl + 1 BiCl3 as colourless crystals. The crystal structure determination (tetragonal, P42/m) consists of nearly regular octahedral [BiCl6]3– anions and two independent Tl+ cations, which have coordination number 8 in form of a slightly distorted cube and 10 in form of an Edshamar polyhedron, respectively. The structure is not isotypic with the recently reported naturally occurring form of Tl3BiCl6, the mineral steropesite. Compound 2 is obtained from a dark red melt of composition TlCl + 2 BiCl3. On rapid cooling, this melt solidifies to a metastable dark red glass which at ambient temperature crystallises to a light amber crystalline powder within some weeks. The structure of 2 was determined by powder diffraction (triclinic, P\bar{1}). A distinct lone pair effect is present causing an irregular coordination on the two independent bismuth atoms. Taking Bi–Cl bonds up to 3.5 Å into account, both bismuth atoms gain coordination number seven. 203Tl and 205Tl solid state NMR and XANES spectra on the Bi and Tl‐LIII edges of both glassy and crystalline TlBi2Cl7 show that a close structural similarity exists between both forms. In contrast, the Raman spectra show distinct differences in the bands of the Bi–Cl vibrations region.
Two AgI–Carboxylate Polymers Involving Ag–Ag Interactions: Syntheses, Structures and Fluorescent Properties
Authors: Li Jun‐Xia , Du Zhong‐Xiang , An Hui‐Qin , Dong Jian‐Xun , Hu Xiao‐Jing , Huang Wei‐Ping
Published: March 2010

Two novel silver complexes [Ag2(Hsal)2]n (1) and [Ag2(oda)]n (2) (H2sal = salicylic acid, H2oda = oxydiacetatic acid) were synthesized hydrothermally by reaction of AgNO3 with H2sal or H2oda and characterized by IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. Compound 1 shows a 2D metal‐organic architecture connected by μ3‐η1:η1:η1‐salicylato ligands and Ag–Ag interactions. Compound 2 displays a 3D metal‐organic network formed by μ7‐(η2:η1)‐(η2:η1)‐η1‐oxydiacetato ligands and Ag–Ag interactions. The photoluminescence properties of both complexes were also investigated.
SrPd4B and BaPd4B: New Type of Crystal Structure and Physical Properties
Authors: Gumeniuk Roman , Schmitt Miriam , Schnelle Walter , Burkhardt Ulrich , Rosner Helge , Leithe‐Jasper Andreas
Published: March 2010

Two new intermetallic alkaline‐earth palladium borides, SrPd4B and BaPd4B were synthesised and their physical properties were investigated. The crystal structure of SrPd4B was solved from powder X‐ray diffraction data: new structure type, space group Pnma, a = 6.0014(1) Å, b = 5.5041(1) Å, c = 11.8723(2) Å, RI = 0.065, RP = 0.093. BaPd4B is isostructural with a = 6.0883(1) Å, b = 5.6066(1) Å, c = 12.0050(2) Å, RI = 0.062, RP = 0.097. The relationship of this structure type with the series of derivatives of the CaCu5 type is discussed. Calculated electronic band structures for palladium, Pd3B, SrPd5, SrPd4B and SrPd3B are compared. The role of boron and strontium for the electronic properties is discussed in detail. SrPd4B shows metallic behaviour with a DOS(EF) ≈︁ 1.7 eV–1·f.u.–1 at the Fermi level. Magnetic properties, electrical resistivity and specific heat capacity measurements reveal that the two compounds are diamagnetic metallic conductors with low electronic density of states, in agreement, with the electronic structure calculations.
Das Indid‐Hydrid Ba9[In]4[H]: Synthese, Kristallstruktur, NMR‐Spektroskopie, Chemische Bindung
Authors: Wendorff Marco , Scherer Harald , Röhr Caroline
Published: March 2010

The new indide hydride Ba9[In]4[H] was synthesized from the elements in stoichiometric proportions using the inherent hydrogen content of commercial elemental barium as hydrogen source. Its structure, constituting a new type, was determined using single‐crystal X‐ray data (tetragonal, space group I4/m, a = 1397.3(2), c = 591.8(1) pm, Z = 2) in sufficient quality (R1 = 0.0261) to allow identification and location of the hydride ion as well as the refinement of its thermal parameter. The crystal structure of Ba9[In]4[H] exhibits isolated indium atoms, which are coordinated by 10 barium cations in a cubicosahedral arrangement. The hydride anions are octahedrally surrounded by six Ba2+ cations. According to [HBa4Ba2/2] these octahedra are connected by opposite corners to form chains running along the c axis. The presence of the hydride ion was determined by solid state NMR spectroscopy, where the chemical shift of the 1H‐MAS‐NMR signal of–9.0 ppm nicely corresponds to the values in BaH2 and other metallid hydrides. Like in other binary alkaline‐earth indides, the band structure calculated in the frame of the FP‐LAPW methods shows a pseudo band gap slightly above the Fermi level, associated with the electron precise valence electron count after Zintl (isolated In5–). The title compound was compared to other hydrides and indides both according to the structural as well as the bonding features.