bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutritional rickets and vitamin D deficiency—association with the outcomes of childhood very severe pneumonia: A prospective cohort study
Authors: Banajeh Salem M. 
Published: November 2009

AbstractBackgroundThe association of rickets and vitamin D deficiency (VDD) with pneumonia is well documented, but not with its outcomes.ObjectivesTo investigate whether rickets and VDD predict the outcomes in very severe pneumonia (VSP).DesignA prospective cohort study conducted at Al‐Sabeen hospital in Sana'a, Yemen. A total of 152 children aged 2–59 months with WHO‐defined VSP were enrolled, managed, and followed for up to 30 days. Treatment outcome was either successful or failure (antibiotic modification for clinical worsening, death, relapse after 10‐day antibiotics, or development of complications). Serum vitamin D (25OHD) was measured in 79 cases. A concentration of ≤30 nmol/L defines VDD.Main Outcome MeasuresAssociation of rickets with treatment outcome; and VDD with the circulating neutrophils (PMNs), and oxygen saturation% (SpO2%), respectively.ResultsTreatment failure occurred in 24 (15.8%), all aged 2–12 months, and 21 (87.5%) were rachitic. Of the 79 subset, 29 had VDD of which 23 (79.3%) had rickets. Treatment failure was significantly higher in the rachitic compared to non‐rachitic [20.6% (21/102) vs. 6% (3/50); OR 1.38 (95% CI 1.13–1.69), P = 0.031]. In multivariate regression, rickets significantly predict a reduced successful treatment compared with non‐rachitic [79.4% (81/102) vs. 94% (47/50); Adjusted OR 0.41 (95% CI 0.20–0.85); P = 0.02]. VDD was strongly associated with reduced PMNs% [Mean (SD) 37 (17) vs. 47 (17); Adjusted OR 0.71 (95% CI 0.53–0.95), P = 0.02], and reduced SpO2% [Mean (SD) 85.9 (7.9) vs. 89.8 (7.1); OR 0.96 (95% CI 0.93–0.99), P = 0.021].ConclusionsIn VSP, rickets was significantly associated with treatment outcome and VDD significantly predict both reduced circulating PMNs, and Day‐5 hypoxemia (SpO2%, <88%). Pediatr Pulmonol. 2009; 44:1207–1215. © 2009 Wiley‐Liss, Inc.
Mapping of ligand‐binding cavities in proteins
Authors: Andersson C. David , Chen Brian Y. , Linusson Anna 
Published: November 2009

AbstractThe complex interactions between proteins and small organic molecules (ligands) are intensively studied because they play key roles in biological processes and drug activities. Here, we present a novel approach to characterize and map the ligand‐binding cavities of proteins without direct geometric comparison of structures, based on Principal Component Analysis of cavity properties (related mainly to size, polarity, and charge). This approach can provide valuable information on the similarities and dissimilarities, of binding cavities due to mutations, between‐species differences and flexibility upon ligand‐binding. The presented results show that information on ligand‐binding cavity variations can complement information on protein similarity obtained from sequence comparisons. The predictive aspect of the method is exemplified by successful predictions of serine proteases that were not included in the model construction. The presented strategy to compare ligand‐binding cavities of related and unrelated proteins has many potential applications within protein and medicinal chemistry, for example in the characterization and mapping of “orphan structures”, selection of protein structures for docking studies in structure‐based design, and identification of proteins for selectivity screens in drug design programs. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Photoluminescence from disorder induced states in individual single‐walled carbon nanotubes
Authors: Harutyunyan Hayk , Gokus Tobias , Green Alexander A. , Hersam Mark C. , Allegrini Maria , Hartschuh Achim 
Published: November 2009

AbstractWe report on the generation of new low‐energy photoluminescence (PL) bands in the spectra of semiconducting single‐walled carbon nanotubes (SWNTs). The new bands, that are brightened because of local modifications of the nanotube structure or the metal adsorption on the SWNT surface, are attributed to PL from different nominally dark excitons that are “brightened” due to defect‐induced mixing of states with different parity and/or spin. The effect of the created structural disorder on the dynamical properties of the emission is studied by time‐resolved PL measurements revealing a significant reduction of the bright exciton lifetime. The lowest energy dark state has a longer lifetime and is not in thermal equilibrium with the bright state.
Raman spectroscopy study on concentrated acid treated carbon nanotubes
Authors: Costa Sara , Scheibe Blazej , Rummeli Mark , Borowiak‐Palen Ewa 
Published: November 2009

AbstractA comparative study will be presented on the effect of strong acid treatments in both single‐walled (SWCNT) and multi‐walled carbon nanotubes (MWCNT). The effects were studied by Raman spectroscopy. The results show that in SWCNT the raw sample shows a broader G band, well fitted by a Breit–Wigner–Fano line in comparison with the acid treated sample, which can be fitted using a Lorentzian lineshape. The original shape of this feature is recovered after the annealing step. In MWCNT samples, a two‐peak G′ band profile was observed after the acid treatment, originated by an exfoliation effect.magnified imageSchematic illustration of the effects of acid treatment. On SWCNT, phase I corresponds to the intercalation in the interstitial channels of the bundles, while phase II is assigned to the intercalation between the walls of neighbouring nanotubes. On MWCNT, intercalation into the walls and consequent exfoliation is represented.
The anomaly of the $\nu$1‐resonance Raman band of bβ‐carotene in solution and in photosystem I and II
Authors: Tschirner Norman , Brose Katharina , Schenderlein Matthias , Zouni Athina , Schlodder Eberhard , Mroginski Maria Andrea , Hildebrandt Peter , Thomsen Christian 
Published: November 2009

AbstractWe have studied the resonance Raman spectra of β‐carotene in solution and in protein‐complexes using laser excitation at various wavelengths in the visible region. Main focus was laid on the ν1‐band, which shows an anomalous behaviour upon variation of the excitation wavelength resulting in a frequency shift of the peak maximum. This shift is due to different excitation profiles of two closely spaced modes as shown previously for β‐carotene in solution. In this work, we have extended the studies to the antenna pigment in photosystems I and II (PS I and PS II).
Interband transmission in armchair graphene ribbons with a step‐like profile of potential energy: Relevance to Klein's tunneling
Authors: Malysheva Lyuba , Petrenko Evgenij , Onipko Alexander 
Published: November 2009

AbstractThree principal results concerning graphene‐based wires and their ambipolar behavior are presented. First, it is the exact expression of the transmission coefficient for armchair graphene wires described by the tight‐binding Hamiltonian with the step‐like change U of site energies. Second, the exact relation between the energy of incident electrons or holes and potential U at which there is no backscattering for the given mode of the transverse motion. Third, the range of relevance of Klein's formula describing the motion of relativistic particles in the same potential profile is established. Analysis of newly derived results shows that physics of interband transitions at constant energy in graphene wires is richer than it was believed.
Electronic transport measurements and Raman spectroscopy on carbon nanotube devices
Authors: Herranen Olli , Rintala Jyri , Johansson Andreas , Queipo Paula , Nasibulin Albert G. , Kauppinen Esko I. , Pettersson Mika , Ahlskog Markus 
Published: November 2009

AbstractAn individual single wall carbon nanotube (SWCNT) device has been fabricated and measured using both low temperature transport and Raman measurements. With these mutually independent methods we can study the correlation between the techniques on semiconducting or metallic behavior of the tube. Furthermore, we study the structure of the nanotube by probing Raman measurements at different spots along the tube axis.
Quantitative composition of a single‐walled carbon nanotube sample: Raman scattering versus photoluminescence
Authors: Heeg Sebastian , Malić Ermin , Casiraghi Cinzia , Reich Stephanie 
Published: November 2009

AbstractWe investigated the spectral data of three carbon nanotube (CNT) species obtained by Raman spectroscopy and photoluminescence (PL) measurements. The corresponding relative signal intensities without further corrections yielded significantly different relative distributions of the CNT species. Theoretical calculations of optical transition probabilities and electron–phonon coupling were included, providing simple models in order to estimate the relative distribution of the three species within the sample. We proposed the product of PL and PL excitation intensities to be a candidate for quantitative analysis of CNT species. Applying the models, we confirmed that both spectroscopic methods agree on one nanotube species dominating the distribution.
Pulsed electrically detected magnetic resonance in organic semiconductors
Authors: Boehme C. , McCamey D. R. , van Schooten K. J. , Baker W. J. , Lee S.‐Y. , Paik S.‐Y. , Lupton J. M. 
Published: November 2009

AbstractCarbon‐based materials have an intrinsically weak spin–orbit coupling which imposes spin selection rules on many electronic transitions. The spin degree of freedom of electrons and nuclei can therefore play a crucial role in the electronic and optical properties of these materials. Spin‐selection rules can be studied via magnetic resonance techniques such as electron–spin resonance and optically detected magnetic resonance as well as electrically detected magnetic resonance (EDMR). The latter has progressed in recent years to a degree where the observation of coherent spin motion via current detection has become possible, providing experimental access to many new insights into the role that paramagnetic centers play for conductivity and photoconductivity. While mostly applied to inorganic semiconductor materials such as silicon, this new, often called pulsed‐(p) EDMR spectroscopy, has much potential for organic (carbon‐based) semiconductors. In this study, progress on the development of pEDMR spectroscopy on carbon‐based materials is reviewed. Insights into materials properties that can be gained from pEDMR experiments are explained and limitations are discussed. Experimental data on radiative polaron‐pair recombination in poly[2‐methoxy‐5‐(20‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene] (MEH‐PPV) organic light emitting diodes (OLEDs) are shown, revealing that under operating conditions the driving current of the device can be modulated by spin‐Rabi nutation of the polaron spin within the charge carrier pairs. From this experimental data it becomes clear that for polaron pairs, the precursor states during exciton formation, exchange interaction is not the predominant influence on the observed pEDMR spectra.
Hydrogen‐induced defect engineering in dilute nitride semiconductors
Authors: Trotta Rinaldo , Polimeni Antonio , Capizzi Mario 
Published: November 2009

AbstractIn dilute nitrides, such as GaAsN, hydrogen‐induced passivation of the electronic activity of N atoms offers an unprecedented opportunity to tune the electronic and structural properties of those materials. By deposition of hydrogen‐opaque metallic masks on GaAsN and subsequent hydrogen irradiation, it is possible to alternate in the growth plane regions having the physical properties of GaAsN with those of N‐passivated GaAsN. After reporting the main characteristics of deuterium diffusion in GaAsN as derived by secondary ion mass spectrometry, we present two examples of hydrogen–induced defect engineering. In the first case, we show that anisotropic strain fields can be created by selective H incorporation. The resulting in‐plane symmetry breaking determines an in‐plane polarization dependence of the light emitted along the crystal growth, otherwise unattainable in bulk GaAsN. Secondly, we report evidence of quantum confinement effects in dot‐like structures obtained by in‐plane patterning of the crystal band gap energy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical nonlinearities and carrier dynamics in semi‐insulating crystals
Authors: Jarašiūnas K. , Kadys A. , Aleksiejūnas R. , Malinauskas T. 
Published: November 2009

AbstractWe analyze conditions when the deep‐impurity governed carrier generation and transport in semi‐insulating crystals create the coexisting free carrier, photorefractive, and absorptive nonlinearities. By monitoring the nonequilibrium carrier and space charge field dynamics via the probe beam diffraction on transient gratings, number of electrical parameters in bulk semi‐insulating crystal have been determined, as carrier lifetime, diffusion coefficient, diffusion length, and sign of carriers, photogenerated from deep traps. We show a novel possibility to record a transient reflection grating via spatial modulation of the deep trap occupation and applicability of this technique to evaluate the compensation ratio of these traps as well as their recombination properties. Experimentally measured diffraction kinetics on free carrier, photorefractive and absorptive gratings in few nanosecond time interval provided the values of diffusion coefficient and carrier lifetime in bulk CdTe and ZnTe crystals, doped by V, Ge, Al, Sc as well in InP:Fe. Carrier transport peculiarities in these crystals revealed the type (n or p) of dominant carriers, generated from the deep impurity levels. In n‐type HVPE GaN crystals, we observed impact of light‐induced space‐charge field to carrier diffusion. The transient reflection gratings in semi‐insulating CdTe:V allowed discrimination of deep trap governed carrier recombination rate from the other recombination channels. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Docking Study and Three‐Dimensional Quantitative Structure‐Activity Relationship (3D‐QSAR) Analyses of Transforming Growth Factor‐β Type I Receptor Kinase Inhibitors
Authors: Yang Min , Zhou Lu , Zuo Zhili , Mancera Ricardo , Song Hang , Tang Xiangyang , Ma Xiang 
Published: November 2009

AbstractTransforming growth factor‐β Type I Receptor Kinase (TGF‐β RI) is an important and novel drug target for the treatment of fibrosis and cancer. In this study, docking and comparative molecular field analysis (CoMFA) were performed and the structural characteristics of TGF‐β RI ligands were rationalized. The genetic algorithm search method in the docking program GOLD 3.0.1 was employed to determine the likely binding mode conformations of 70 inhibitors in the active site of TGF‐β RI. Based on the binding mode conformations, a highly predictive 3D‐QSAR model was developed with a q2 value of 0.589 for CoMFA. The predictive ability of this model was validated with a number of compounds that were not included in the original training set. Furthermore, the 3D‐QSAR model was mapped back to the binding site of the TGF‐β RI to obtain a better understanding of the essential interactions between the inhibitors and TGF‐β RI. The robustness, predictive ability and automated alignment generation of this model make it a potential tool for the design and development of new drug leads to inhibit TGF‐β RI.
Synthesis, Antimycobacterial Activity and 3‐D QSAR Studies of Some New Derivatives of p‐Hydroxybenzohydrazide
Authors: Bhole Ritesh. P. , Bhusari Kishore P. 
Published: November 2009

AbstractVarious N′‐[3‐(4‐substituted alkyl/aryl thiaiazolidin‐2‐ylidene]‐4‐hydroxy benzohydrazide (4.a–i) and N′‐[‐(3,4‐disubstituted)‐1,3‐thiazolidin‐2ylidene)]‐4‐hydroxybenzohydrazide from (5.a–i) to (10.a–i) were synthesized using appropriate synthetic route. The entire test compounds (4.a–i) and compounds from (5.a–i) to (10.a–i) were assayed in vitro against H37Rv strain of M. tuberculosis. The minimum inhibitory concentration (MIC) was determined for test compounds and for reference standards. The test compounds showed significant antimycobacterial activity against the microbial strains used, when tested in vitro. In general, p‐hydroxybenzohydrazide ring and substituted thiazoline ring are essential for antimicrobial activity. Among the compounds tested, compounds 5.i, 6.f, 7.d, 8.g and 9.f were found to be most potent. The test compounds were found to be nontoxic up to a dose level of 1000 μg/mL. All compounds were then subjected for 3D‐QSAR studies. 3D‐QSAR study based on the principal of alignment of pharmacophoric features by Schrodinger PHASE module. The 3D‐QSAR study allowed us to confirm the preferential binding mode of p‐hydroxybenzohydrazide inside the active site.
Ultrasmall Near‐Infrared Non‐cadmium Quantum Dots for in vivo Tumor Imaging
Authors: Gao Jinhao , Chen Kai , Xie Renguo , Xie Jin , Lee Seulki , Cheng Zhen , Peng Xiaogang , Chen Xiaoyuan 
Published: November 2009

AbstractThe high tumor uptake of ultrasmall near‐infrared quantum dots (QDs) attributed to the enhanced permeability and retention effect is reported. InAs/InP/ZnSe QDs coated by mercaptopropionic acid (MPA) exhibit an emission wavelength of about 800 nm (QD800‐MPA) with very small hydrodynamic diameter (<10 nm). Using 22B and LS174T tumor xenograft models, in vivo and ex vivo imaging studies show that QD800‐MPA is highly accumulated in the tumor area, which is very promising for tumor detection in living mice. The ex vivo elemental analysis (Indium) using inductively coupled plasma (ICP) spectrometry confirm the tumor uptake of QDs. The ICP data are consistent with the in vivo and ex vivo fluorescence imaging. Human serum albumin (HSA)‐coated QD800‐MPA nanoparticles (QD800‐MPA‐HSA) show reduced localization in mononuclear phagocytic system‐related organs over QD800‐MPA plausibly due to the low uptake of QD800‐MPA‐HSA in macrophage cells. QD800‐MPA‐HSA may have great potential for in vivo fluorescence imaging.
A Genetic Strategy for Single and Combinatorial Analysis of miRNA Function in Mammalian Hematopoietic Stem Cells
Authors: Papapetrou Eirini P. , Korkola James E. , Sadelain Michel 
Published: November 2009

Abstract
The regulatory role of micro-RNAs (miRNAs) in hematopoietic development is increasingly appreciated. Reverse genetics strategies based on the targeted disruption of miRNAs offer a powerful tool to study miRNA functions in mammalian hematopoiesis. The miR-144/451 cluster comprises two miRNAs coexpressed from a common precursor transcript in an erythroid-specific manner. To decipher the contribution of each miRNA of the cluster in mammalian erythropoiesis, we developed a strategy for stable in vivo individual and combinatorial miRNA inhibition. We developed decoy target sequences for each miRNA expressed by lentiviral vectors marked with distinct fluorescent proteins and used them to probe the functions of miR-144 and miR-451 in the murine hematopoietic system in a competitive repopulation setting. Murine hematopoietic chimeras expressing lentiviral-encoded inhibitory sequences specific for miR-144 or miR-451 exhibited markedly reduced Ter119+ erythroblast counts, with the combined knockdown showing additive effect. These chimeras showed abnormal patterns of erythroid differentiation primarily affecting the proerythroblast to basophilic erythroblast transition, coinciding with the stage where expression of the miRNA cluster is dramatically induced and posttranscriptional gene regulation becomes prominent. These results reveal a role for the miR-144/451 locus in mammalian erythropoiesis and provide the first evidence of functional cooperativity between clustered miRNAs in the hematopoietic system. The strategy described herein will prove useful in functional miRNA studies in mammalian hematopoietic stem cells.
Electrical Conductivity Studies on Individual Conjugated Polymer Nanowires: Two-Probe and Four-Probe Results
Authors: Long YunZe , Duvail JeanLuc , Li MengMeng , Gu Changzhi , Liu Zongwen , Ringer Simon P 
Published: November 2009

Abstract
Two- and four-probe electrical measurements on individual conjugated polymer nanowires with different diameters ranging from 20 to 190 nm have been performed to study their conductivity and nanocontact resistance. The two-probe results reveal that all the measured polymer nanowires with different diameters are semiconducting. However, the four-probe results show that the measured polymer nanowires with diameters of 190, 95–100, 35–40 and 20–25 nm are lying in the insulating, critical, metallic and insulting regimes of metal–insulator transition, respectively. The 35–40 nm nanowire displays a metal–insulator transition at around 35 K. In addition, it was found that the nanocontact resistance is in the magnitude of 104Ω at room temperature, which is comparable to the intrinsic resistance of the nanowires. These results demonstrate that four-probe electrical measurement is necessary to explore the intrinsic electronic transport properties of isolated nanowires, especially in the case of metallic nanowires, because the metallic nature of the measured nanowires may be coved by the nanocontact resistance that cannot be excluded by a two-probe technique.
One-Pot Green Synthesis and Bioapplication ofl-Arginine-Capped Superparamagnetic Fe3O4 Nanoparticles
Authors: Lai Yongchao , Yin Weiwei , Liu Jinting , Xi Rimo , Zhan Jinhua 
Published: November 2009

Abstract
Water-solublel-arginine-capped Fe3O4 nanoparticles were synthesized using a one-pot and green method. Nontoxic, renewable and inexpensive reagents including FeCl3,l-arginine, glycerol and water were chosen as raw materials. Fe3O4 nanoparticles show different dispersive states in acidic and alkaline solutions for the two distinct forms of surface bindingl-arginine. Powder X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the structure of Fe3O4 nanocrystals. The products behave like superparamagnetism at room temperature with saturation magnetization of 49.9 emu g−1 and negligible remanence or coercivity. In the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride, the anti-chloramphenicol monoclonal antibodies were connected to thel-arginine-capped magnetite nanoparticles. The as-prepared conjugates could be used in immunomagnetic assay.
(See supplementary material 1)
Synthesis and Properties of Polyurethane Elastomers with Castor Oil as Crosslinker
Authors: Oprea Stefan 
Published: November 2009

AbstractCastor oil–polyurethane elastomers were prepared by reacting poly (1,4‐butane diol) (Terathane 1400) with aliphatic 1,6‐hexamethylene diisocyanate. The prepolymers were chain‐extended with bifunctional precursor chains and/or with castor oil as a trifunctional crosslinker at stoichiometric ratios. These resulted in a series of crosslinked polyurethane elastomers with different structures of the hard segment. The properties of the material were measured by differential scanning calorimetry, thermogravimetric analysis, atomic force microscopy, as well as tensile properties measurements. The effect of stoichiometric balance (i.e., OH/NCO molar ratio) on the final properties was evaluated. The formation of hydrogen bonds was observed by Fourier transform infrared.spectroscopy The measured properties were found to be strongly influenced by the molar ratio of chain extenders to the diisocyanate component. The glass transition temperatures (Tg) for the polyurethanes with OHpolyol/NCO/OHchain extender having molar ratios of 1:2:1 and 1:4:3 were found to be −70 and −57 °C, respectively. The polyurethanes networks with a OH/NCO molar ratio of 1:2:1 had excellent mechanical properties, indicating that this is the optimum ratio to be used in castor oil polyurethane elastomer formulations. The objective of this work was to study the effect of the castor oil crosslinker on the morphology of the resulting crosslinked polyurethanes and to correlate the morphology with the properties of these bio‐based crosslinked polyurethanes.