bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell shape and TGF‐β signaling define the choice of lineage during in vitro differentiation of mouse primary hepatic precursors
Authors: Akkari Leila , Haouzi Delphine , Binamé Fabien , Floc'h Nicolas , Lassus Patrice , Baghdiguian Stephen , Hibner Urszula
Published: May 2010

Cellular differentiation relies on both physical and chemical environmental cues. The bipotential mouse embryonic liver (BMEL) cells are early progenitors of liver epithelial cells with an apparently infinite proliferative potential. These cells, which remain undifferentiated in a monolayer culture, differentiate upon release from geometrical constraints imposed by growth on a stiff plastic plate. In a complex three dimensional environment of a Matrigel extracellular matrix, BMEL cells form two types of polarized organoids of distinct morphologies: cyst‐like structures suggesting cholangiocyte‐type organization or complex organoids, reminiscent of liver parenchyma and associated with acquisition of hepatocyte‐specific phenotypic markers. The choice of the in vitro differentiation lineage is governed by Transforming Growth Factor‐β (TGF‐β) signaling. Our results suggest that morphological cues initiate the differentiation of early hepatic precursors and confirm the inhibitory role of TGF‐β on hepatocytic lineage differentiation. J. Cell. Physiol. 225: 186–195, 2010. © 2010 Wiley‐Liss, Inc.
12‐O‐tetradecanoylphorbol‐13‐acetate‐induced invasion/migration of glioblastoma cells through activating PKCα/ERK/NF‐κB‐dependent MMP‐9 expression
Authors: Lin Cheng‐Wei , Shen Shing‐Chuan , Chien Chih‐Chiang , Yang Liang‐Yo , Shia Lin‐Ting , Chen Yen‐Chou
Published: May 2010

An increase in MMP‐9 gene expression and enzyme activity with stimulating the migration of GBM8401 glioma cells via wound healing assay by 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) was detected in glioblastoma cells GBM8401. TPA‐induced translocation of protein kinase C (PKC)α from the cytosol to membranes, and migration of GBM8401 elicited by TPA was suppressed by adding the PKCα inhibitors, GF109203X and H7. Activation of extracellular signal‐regulated kinase (ERK) and c‐Jun‐N‐terminal kinase (JNK) by TPA was identified, and TPA‐induced migration and MMP‐9 activity was significantly blocked by ERK inhibitor PD98059 and U0126, but not JNK inhibitor SP600125. Activation of NF‐κB protein p65 nuclear translocation and IκBα protein phosphorylation with increased NF‐κB‐directed luciferase activity by TPA were observed, and these were blocked by the PD98059 and IkB inhibitor BAY117082 accompanied by reducing migration and MMP‐9 activity induced by TPA in GBM8401 cells. Transfection of GBM8401 cells with PKCα siRNA specifically reduced PKCα protein expression with blocking TPA‐induced MMP‐9 activation and migration. Additionally, suppression of TPA‐induced PKCα/ERK/NK‐κB activation, migration, and MMP‐9 activation by flavonoids including kaempferol (Kae; 3,5,7,4′‐tetrahydroxyflavone), luteolin (Lut; 5,7,3′4′‐tetrahydroxyflavone), and wogonin (Wog; 5,7‐dihydroxy‐8‐methoxyflavone) was demonstrated, and structure–activity relationship (SAR) studies showed that hydroxyl (OH) groups at C4′ and C8 are critical for flavonoids' action against MMP‐9 enzyme activation and migration/invasion of glioblastoma cells elicited by TPA. Application of flavonoids to prevent the migration/invasion of glioblastoma cells through blocking PKCα/ERK/NF‐κB activation is first demonstrated herein. J. Cell. Physiol. 225: 472–481, 2010. © 2010 Wiley‐Liss, Inc.
CXCR4‐independent rescue of the myeloproliferative defect of the gata1low myelofibrosis mouse model by Aplidin®
Authors: Verrucci Maria , Pancrazzi Alessandro , Aracil Miguel , Martelli Fabrizio , Guglielmelli Paola , Zingariello Maria , Ghinassi Barbara , D'Amore Emanuela , Jimeno José , Vannucchi Alessandro M. , Migliaccio Anna Rita
Published: May 2010

The discovery of JAK2 mutations in Philadelphia‐negative myeloproliferative neoplasms has prompted investigators to evaluate mutation‐targeted treatments to restore hematopoietic cell functions in these diseases. However, the results of the first clinical trials with JAK2 inhibitors are not as promising as expected, prompting a search for additional drugable targets to treat these disorders. In this paper, we used the hypomorphic Gata1low mouse model of primary myelofibrosis (PMF), the most severe of these neoplasms, to test the hypothesis that defective marrow hemopoiesis and development of extramedullary hematopoiesis in myelofibrosis is due to insufficient p27Kip1 activity and is treatable by Aplidin®, a cyclic depsipeptide that activates p27Kip1 in several cancer cells. Aplidin® restored expression of Gata1 and p27Kip1 in Gata1low hematopoietic cells, proliferation of marrow progenitor cells in vitro and maturation of megakaryocytes in vivo (reducing TGF‐β/VEGF levels released in the microenvironment by immature Gata1low megakaryocytes). Microvessel density, fibrosis, bone growth, and marrow cellularity were normal in Aplidin®‐treated mice and extramedullary hematopoiesis did not develop in liver although CXCR4 expression in Gata1low progenitor cells remained low. These results indicate that Aplidin® effectively alters the natural history of myelofibrosis in Gata1low mice and suggest this drug as candidate for clinical evaluation in PMF. J. Cell. Physiol. 225: 490–499, 2010. © 2010 Wiley‐Liss, Inc.
Evidences of a role for eukaryotic translation initiation factor 5A (eIF5A) in mouse embryogenesis and cell differentiation
Authors: Parreiras‐e‐Silva Lucas T. , Luchessi Augusto D. , Reis Rosana I. , Oliver Constance , Jamur Maria C. , Ramos Ricardo G.P. , Oliveira Eduardo B. , Curi Rui , Costa‐Neto Claudio M.
Published: May 2010

Eukaryotic translation initiation factor 5A (eIF5A) has a unique character: the presence of an unusual amino acid, hypusine, which is formed by post‐translational modifications. Even before the identification of hypusination in eIF5A, the correlation between hypusine formation and protein synthesis, shifting cell proliferation rates, had already been observed. Embryogenesis is a complex process in which cellular proliferation and differentiation are intense. In spite of the fact that many studies have described possible functions for eIF5A, its precise role is under investigation, and to date nothing has been reported about its participation in embryonic development. In this study we show that eIF5A is expressed at all mouse embryonic post‐implantation stages with increase in eIF5A mRNA and protein expression levels between embryonic days E10.5 and E13.5. Immunohistochemistry revealed the ubiquitous presence of eIF5A in embryonic tissues and organs at E13.5 day. Interestingly, stronger immunoreactivity to eIF5A was observed in the stomodeum, liver, ectoderm, heart, and eye, and the central nervous system; regions which are known to undergo active differentiation at this stage, suggesting a role of eIF5A in differentiation events. Expression analyses of MyoD, a myogenic transcription factor, revealed a significantly higher expression from day E12.5 on, both at the mRNA and the protein levels suggesting a possible correlation to eIF5A. Accordingly, we next evidenced that inhibiting eIF5A hypusination in mouse myoblast C2C12 cells impairs their differentiation into myotubes and decreases MyoD transcript levels. Those results point to a new functional role for eIF5A, relating it to embryogenesis, development, and cell differentiation. J. Cell. Physiol. 225: 500–505, 2010. © 2010 Wiley‐Liss, Inc.
Establishment of a new conditionally immortalized human brain microvascular endothelial cell line retaining an in vivo blood–brain barrier function
Authors: Sano Yasuteru , Shimizu Fumitaka , Abe Masaaki , Maeda Toshihiko , Kashiwamura Yoko , Ohtsuki Sumio , Terasaki Tetsuya , Obinata Masuo , Kajiwara Koji , Fujii Masami , Suzuki Michiyasu , Kanda Takashi
Published: May 2010

The breakdown of the blood–brain barrier (BBB) has been considered to be a key step in the disease process of a number of neurological disorders such as cerebral ischemia and Alzheimer's disease. Many in vitro BBB models derived from animal tissues have been established to elucidate the mechanism of BBB insufficiency. However, only a few human immortalized in vitro BBB models have been reported. In the present study, a temperature‐sensitive SV40‐T antigen was introduced to immortalize cells using a retrovirus to obtain a better human in vitro BBB model which sustains physiological properties. This endothelial cell (EC) line, termed TY08, showed a spindle‐shaped morphology. The cells expressed all key tight junctional proteins, such as occludin, claudin‐5, zonula occludens (ZO)‐1 and ZO‐2 at their cell‐to‐cell boundaries, and had low permeability to inulin across its monolayer. The cells also expressed various influx and efflux transporters and exhibited the functional expression of p‐glycoprotein. Furthermore, the TY08 cells grew and proliferated well under the permissive temperature and stopped growing under the non‐permissive temperature to serve as physiological ECs forming the BBB. Thus, conditionally immortalized TY08 cells retaining the in vivo BBB functions should facilitate analyses for determining the pathophysiology of various neurological diseases. J. Cell. Physiol. 225: 519–528, 2010. © 2010 Wiley‐Liss, Inc.
Synthesis of 4,7‐disubstituted spirobenzofuran‐2(3H)‐cyclohexanes
Authors: Bradbury Barton J. , Sindelar Robert D.
Published: May 2010

A general synthetic strategy was designed for the preparation of 7‐substituted‐4‐methoxy‐ and 4‐hydroxyspiro[benzofuran‐2(3H)‐cyclohexanes] 5 and 6 (Figure 1) using successive, regioselective hetero‐atom‐facilitated aromatic lithiation reactions and subsequent reaction with various electrophiles.
Synthesis of certain 1‐β‐D‐ribofuranosyl‐1,2‐dihydro‐2‐oxopyridines structurally related to nicotinamide ribonucleoside
Authors: Hanna Naeem B. , Joshi Ramachandra V. , Larson Steven B. , Robins Roland K. , Revankar Ganapathi R.
Published: May 2010

Several substituted 1‐β‐D‐ribofuranosyl‐1,2‐dihydro‐2‐oxopyridines have been prepared as congeners of nicotinamide ribonucleoside. Direct glycosylation of the silylated 3‐ethylcarboxylate 5 or 3‐carbamoyl 6 derivative of 1,2‐dihydro‐2‐oxopyridine with 1,2,3,5‐tetra‐O‐acetyl‐β‐D‐ribofuranose (7) in the presence of trimethylsilyl triflate gave the corresponding blocked nucleosides 8 and 9, respectively in good yield. Ammonolysis of 8 and 9 with methanolic ammonia furnished 1‐β‐D‐ribofuranosyl‐1,2‐dihydro‐2‐oxopyridine‐3‐carboxa‐mide (10), the structure of which was established by single‐crystal X‐ray diffraction analysis. Thiation of 9 with Lawesson's reagent and subsequent deacetylation of the thiated product 11 with methanolic ammonia furnished 1‐β‐D‐ribofuranosyl‐1,2‐dihydro‐2‐oxopyridine‐3‐thiocarboxamide (12). Modification of the carbo‐nitrile function of 1‐(2,3,5‐tri‐O‐acetyl‐β‐D‐ribofuranosyl)‐1,2‐dihydro‐2‐oxopyridine‐4‐carbonitrile (13) gave a series of 4‐substituted‐1‐β‐D‐ribofuranosyl‐1,2‐dihydro‐2‐oxopyridines, in which the 4‐substituent is a thiocarboxamide 15, carboxamide 16, carboxamidoxime 17, carboxamidine 18 and aminomethyl 19 group. None of these compounds exhibited any significant antitumor or antiviral effects in vitro.
Preparation of Metal‐free phthalocyanine using the benzenetellurolate ion
Authors: Kitahara Kiyoshi , Asano Toyofumi , Tokita Sumio , Nishi Hisao
Published: May 2010

Metal‐free phthalocyanine was prepared from o‐phthalonitrile using the benzenetellurolate ion in ethanol. Furthermore, the yield of metal‐free phthalocyanine using the benzenetellurolate ion was compared with that using the benzeneselenolate ion or the benzenethiolate ion.
Inline pneumatically assisted atmospheric pressure matrix‐assisted laser desorption/ionization ion trap mass spectrometry
Authors: Navare Arti T. , Fernández Facundo M.
Published: May 2010

Atmospheric pressure (AP) matrix‐assisted laser desorption/ionization (MALDI) is known to suffer from poor ion transfer efficiencies as compared to conventional vacuum MALDI (vMALDI). To mitigate these issues, a new AP‐MALDI ion source utilizing a coaxial gas flow was developed. Nitrogen, helium, and sulfur hexafluoride were tested for their abilities as ion carriers for a standard peptide and small drug molecules. Nitrogen showed the best ion transport efficiency, with sensitivity gains of up to 1900% and 20% for a peptide standard when the target plate voltage was either continuous or pulsed, respectively. The addition of carrier gas not only entrained the ions efficiently but also deflected background species and declustered analyte–matrix adducts, resulting in higher absolute analyte signal intensities and greater signal‐to‐noise (S/N) ratios. With the increased sensitivity of pneumatically assisted (PA) AP‐MALDI, the limits of detection of angiotensin I were 20 or 3 fmols for continuous or pulsed target plate voltage, respectively. For analyzing low‐mass analytes, it was found that very low gas flow rates (0.3–0.6 l min−1) were preferable owing to increased fragmentation at higher gas flows. The analyte lability, type of gas, and nature of the extraction field between the target plate and mass spectrometer inlet were observed to be the most important factors affecting the performance of the in‐line PA‐AP‐MALDI ion source. Copyright © 2010 John Wiley & Sons, Ltd.
Anomeric discrimination and rapid analysis of underivatized lactose, maltose, and sucrose in vegetable matrices by U‐HPLC–ESI‐MS/MS using porous graphitic carbon
Authors: Gabbanini Simone , Lucchi Elena , Guidugli Federico , Matera Riccardo , Valgimigli Luca
Published: May 2010

Lactose intolerance is a common condition caused by intestinal lactase deficiency, and a lactose‐free diet represents the simplest way to avoid gastrointestinal symptoms. The emerging use of dietary supplements requires analytical tools that are capable of assessing these analytes, particularly for those based on dry herbal extracts that contain lactose together with maltose and sucrose, because of cross‐contamination and/or deliberate addition as excipient. Electrospray ionization mass spectrometry (ESI‐MS) and MS/MS are valuable detection methods for underivatized disaccharides; however, the absence of distinctive ions and collision‐induced dissociation (CID) fragmentation patterns does not allow discrimination of stereoisomers without good chromatographic resolution. We developed an ultrahigh performance liquid chromatography‐ESI (U‐HPLC‐ESI) approach, based on porous graphitic carbon (PGC) columns, working at 5 °C to separate and detect the disaccharides in their anomeric forms as formate adducts obtained directly in‐column by eluting with formate buffer/acetonitrile gradient mixtures. Using a Paul trap, we monitored the adducts [M + HCOO]− at m/z 387 in ESI negative mode (MS1) as well as the CID fragment ion [M − H]− at m/z 341 (MS2) and used MS3 fragment ions at m/z 178 and 161 to confirm disaccharides identity in complex vegetable matrices. Complete resolution of lactose α‐ and β‐anomers, maltose α‐ and β‐anomers, and sucrose was obtained with R ≥ 2.0 for all peaks and selectivity α = 1.2 between α‐ and β‐anomers of lactose. The limits of detection were in the range of 3–7 µg/l (ppb) for the target disaccharides. Because of the rapidity and good anomeric discrimination, the described method represents an alternative tool to investigate the mutarotation phenomenon for reducing disaccharides. Copyright © 2010 John Wiley & Sons, Ltd.
Simultaneous determination of the composition and temperature gradients in the vicinity of boiling bubbles in liquid binary mixtures using one‐dimensional Raman measurements
Authors: Knauer O. S. , Lang M. C. , Braeuer A. , Leipertz A.
Published: May 2010

The ability to transport large quantities of heat by nucleate boiling is reduced for mixtures compared to their pure components. To study the heat and mass transfer during the boiling process, a one‐dimensional Raman spectroscopy setup was applied to measure, for the first time to the best of our knowledge, the composition and temperature gradients in the vicinity of single boiling bubbles of a mixture of acetone and isopropanol. A novel evaluation strategy allowed the simultaneous detection of the mixture composition and temperature from the CH and the OH Raman spectra. The composition gradients arise because of rectification effects, which cause unlike compositions in the gas and liquid phases. Heat transfer from the boiling bubble to the surrounding liquid induces temperature gradients. High temporal and spatial resolution measurements using an imaging spectrograph and an electron multiplying charge‐coupled device camera revealed large composition and temperature gradients with similar shapes. The accuracy of the composition results was validated by a species conservation calculation. Copyright © 2010 John Wiley & Sons, Ltd.
NMR‐based analysis of structure of heteroleptic triple‐decker (phthalocyaninato) (porphyrinato) lanthanides in solutions
Authors: Birin Kirill P. , Gorbunova Yulia G. , Tsivadze Aslan Yu.
Published: May 2010

A novel approach for the structural analysis of heteroleptic triple‐decker (porphyrinato)(phthalocyaninato) lanthanides(III) in solutions is developed. The developed approach consists in molecular mechanics (MM+) optimization of the geometry of the complex taking into account the lanthanide‐induced shift (LIS) datasets. LISs of the resonance peaks in 1H NMR spectra of a series of symmetric complexes [An4P]Ln[(15C5)4Pc]Ln[An4P], where An4P2− is 5,10,15,20‐tetrakis(4‐methoxyphenyl)porphyrinato‐dianion, [(15C5)4Pc]2− is 2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninato‐dianion and Ln = La, Ce, Pr, Nd, Sm, Eu, are analyzed. Analysis of LISs showed two sets of protons in the molecule with opposite signs of shift. Two‐nuclei analysis of LISs testifies isostructurality of the whole series of investigated complexes in solution despite contraction of the lanthanide ions. Model‐free separation of contact and dipolar contributions of LISs was performed with one‐nucleus technique and did not show changes in contact and dipolar terms within the investigated series. MM+ optimization of the molecular structure allowed the interpretation of features of LIS for each particular group of protons. Parameterization of MM + ‐optimized model of molecule with values of structure‐dependent dipolar contributions of LIS allows the development of the precise structural model of the triple‐decker complex in solution. This approach allows the determination of the geometry and structure of the sandwich macrocyclic tetrapyrrolic complexes together with conformational analysis of flexible peripheral substituents in solutions. The developed method can be applied with minor modifications for the determination of structural parameters of other types of lanthanides(III) complexes with tetrapyrrolic ligands and also supramolecular systems based on them. Copyright © 2010 John Wiley & Sons, Ltd.
Glutaraldehyde crosslinked gelatin/hydroxyapatite nanocomposite scaffold, engineered via compound techniques
Authors: Azami Mahmoud , Rabiee Mohammad , Moztarzadeh Fathollah
Published: May 2010

In this study, a scaffold was designed to be used in bone tissue repair and the effect of glutaraldehyde (GA) concentration as crosslinking agent was investigated. To mimic the mineral and organic component of natural bone, hydroxyapatite (HAp) and gelatin (GEL) were used as the main components of this composite. Nanopowders of HAp were synthesized and also used together with GEL to engineer a three‐dimensional nanocomposite scaffold. The results show that GEL/HAp nanocomposite is porous with three‐dimensional interconnected structure, pore sizes ranging from 300 to 500 μm, and about 85% porosity. In addition, increasing GA concentration provokes the enhancement of compressive strength until 1 w/v% GA solution followed by a reduction to 2.5%, whereas it causes work fracture to decrease. It was concluded that optimum concentration for crosslinking GEL matrix for this purpose is 1 w/v% GA solution. A specific combination of commonly used techniques applied to engineer a scaffold with almost ideal properties intended for the bone tissue engineering is introduced. In addition, scaffolds that are prepared via this compound process has the potential to be used in the solid free form applications and so being formed in any dimension and geometry relevant to the defect size and shape. POLYM. COMPOS., 31:2112–2120, 2010. © 2010 Society of Plastics Engineers
Motor performance is better than normal in preschool children with cystic fibrosis
Authors: Gruber Wolfgang , Orenstein David M. , Paul Karl , Hüls Gerd , Braumann Klaus M.
Published: May 2010

The aim of the present study was to assess the motor performance in preschool children with a reliable and valid test battery developed to identify motor dysfunction and normal motor development in children aged from 4 to 6 years. Several aspects of motor performance were examined in 29 preschool children with cystic fibrosis (CF) age range 4–6 years (mean 5.2 ± 0.8 years), FEV1 97.2 ± 15.3pred and compared to with 22 healthy children of the same age 5.5 ± 0.8 years. All children performed the “Motoriktest fuer 4‐6jaehrige Kinder” (MOT) assessing seven different aspects of motor performance. Compared to healthy children, test score “Motor Quotient” (MQ) as the mean of all test items was significantly higher (P < 0.05) in children with CF (108.1 ± 16 vs. 93.5 ± 17.9). In both groups, the MQ can be classified as normal. Children with CF scored higher in MOT subtests “Agility and Coordination” (P < 0.05) and “Balance” (P < 0.01) than healthy children but not in the other subtests. We speculate that chest physiotherapy in preschool children with CF may have an effect on motor performance in general and in some aspects of motor performance. Pediatr Pulmonol. 2010; 45:527–535. © 2010 Wiley‐Liss, Inc.
Probiotic supplementation affects pulmonary exacerbations in patients with cystic fibrosis: A pilot study
Authors: Weiss Batia , Bujanover Yoram , Yahav Yaakov , Vilozni Daphna , Fireman Elizabeth , Efrati Ori
Published: May 2010

Objective

Probiotics reduce intestinal inflammation in, and Lactobacillus GG (LGG) reduces pulmonary exacerbation rate cystic fibrosis (CF) patients. We intended to determine the effect of a mixed probiotic preparation on pulmonary exacerbations and inflammatory characteristics of the sputum in CF patients.

Study Design

A prospective pilot study of 10 CF patients with mild–moderate lung disease and Pseudomonas aeruginosa colonization, treated with probiotics for 6 months. Pulmonary function tests (PFT's), sputum cultures with semi‐quantitative bacterial analysis, and sputum neutrophil count and interleukin‐8 (IL‐8) levels were compared to pre‐treatment and post‐treatment values. The rate of pulmonary exacerbations was compared to 2 years prior to the study.

Results

The exacerbation rate was significantly reduced in comparison to the previous 2 years and to 6 months post‐treatment (P = 0.002). PFT's have not changed at the end of treatment and during 6 months post‐treatment. No change in sputum bacteria, neutrophil count, and IL‐8 levels was observed.

Conclusion

Probiotics reduce pulmonary exacerbations rate in patients with CF. Probiotics may have a preventive potential for pulmonary deterioration in CF patients. Pediatr Pulmonol. 2010; 45:536–540. © 2010 Wiley‐Liss, Inc.
Endoscopy for the initial suspicion of vascular rings in tracheoesophageal compressions: Correlation with surgical findings
Authors: Furuya María E.Y. , Vargas Mario H. , Ramírez‐Figueroa Jorge Luis , Félix‐Heredia José Luis , González‐Ortíz Beatriz , Rodríguez‐Hernández Lydia , Vera‐Canelo José Manuel
Published: May 2010

Vascular rings (VR) may produce extrinsic compression of trachea and/or esophagus. Diagnosis relies on nonspecific clinical data from resulting compression and image studies, mainly angiography, computed tomography, and cardiovascular MRI. Because of their low incidence, diagnosis is often missed. The role of bronchoscopy and esophagoscopy is controversial, but these procedures might establish for the first time the diagnostic suspicion of VR. This communication was aimed to determine to what extent endoscopic manifestations lead the clinician to suspect the presence of a VR and, moreover, to define their correlation with surgical findings.

Methods

Children with endoscopic diagnosis of VR submitted to surgery were retrospectively analyzed.

Results

Twenty patients fulfilled inclusion criteria. They were submitted to 19 bronchoscopies and 16 esophagoscopies, and in 60% cases they raised the first suspicion of VR. Diagnostic agreement of the type of VR between endoscopy and surgery was 85%. Bronchoscopy diagnosed 12 VR, and in 10 cases predicted the specific type of VR. Additional relevant findings were detected in nine patients (47.4%). Esophagoscopy diagnosed VR in 14 patients, predicted the specific type in 78.6% and detected all aberrant right subclavian artery cases.

Conclusions

Initial suspicion of VR was raised by bronchoscopic and/or esophagoscopic findings in 60% cases. Endoscopy proved to be a valuable tool to anticipate the type of malformation and to disclose associated abnormalities. Pediatr Pulmonol. 2010; 45:560–565. © 2010 Wiley‐Liss, Inc.
Reactive Flow Model Parameter Estimation Using Genetic Algorithms
Authors: Baranda Ribeiro Jose , Mendes Ricardo , Silva Cristóvão
Published: May 2010

An original real‐coded genetic algorithm methodology that has been developed for the estimation of the parameters of the Tarver reactive flow model of shock initiation and detonation of heterogeneous solid explosives is described in detail. This methodology allows, in a single optimisation procedure and without the need for a starting solution, to search for the 15 parameters of the reaction rate law of the reactive flow model that fit the numerical results to the experimental ones. The developed methodology was applied and tested with an experimental situation, described in detail in the literature, involving the acceleration of a tantalum metal plate by an LX‐17 explosive charge. The obtained parameters allow a very good description of the experimental results and are close to the ones originally used by Tarver and co‐authors in their simulation of the phenomenon.
Characterization of a Series of Nitrogen‐Rich Molecules using Laser Induced Breakdown Spectroscopy
Authors: De Lucia Frank C. , Gottfried Jennifer L.
Published: May 2010

A series of nitrogen‐rich molecules, such as 5‐aminotetrazolium nitrate (HAT‐NO3) and hydrazinebistetrazole (HBT), bis(2,2,2‐trinitroethyl)‐hydrazodicarboxylate (BTHC), cyclotrimethylene trinitramine (RDX), trinitrotoluene (TNT), melamine, sucrose, and L‐glutamine were studied using laser‐induced breakdown spectroscopy (LIBS). The atomic emission intensities and intensity ratios of the constituent elements from the LIBS spectrum were shown to correlate with the mole fractions and stoichiometries of the molecules. In addition, the amount of oxygen present in the molecule influenced the emission intensities of molecular fragments such as C2. Finally, we used principal components analysis to analyze the data from the LIBS spectra and separate the different organic molecules based on the atomic emission intensities and ratios.
Solution‐phase submonomer diversification of aza‐dipeptide building blocks and their application in aza‐peptide and aza‐DKP synthesis
Authors: Bourguet Carine B. , Proulx Caroline , Klocek Sophie , Sabatino David , Lubell William D.
Published: May 2010

Aza‐peptides have been used as tools for studying SARs in programs aimed at drug discovery and chemical biology. Protected aza‐dipeptides were synthesized by a solution‐phase submonomer approach featuring alkylation of N‐terminal benzophenone semicarbazone aza‐Gly‐Xaa dipeptides using different alkyl halides in the presence of potassium tert‐butoxide as base. Benzophenone protected aza‐dipeptide tert‐butyl ester 31c was selectively deprotected at the C‐terminal ester or N‐terminal hydrazone to afford, respectively, aza‐dipeptide acid and amine building blocks 36c and 40c, which were introduced into longer aza‐peptides. Alternatively, removal of the benzophenone semicarbazone protection from aza‐dipeptide methyl esters 29a–c led to intramolecular cyclization to produce aza‐DKPs 39a–c. In light of the importance of aza‐peptides and DKPs as therapeutic agents and probes of biological processes, this diversity‐oriented solution‐phase approach may provide useful tools for studying peptide science. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Design optimization of quantum cascade laser structures at λ ∼ 11–12 µm
Authors: Ko Yeong Hwan , Yu Jae Su
Published: May 2010

By a simulation optimization technique, we design In0.53Ga0.47As/In0.52Al0.48As quantum cascade laser (QCL) structures, based on a four‐quantum well (QW) active region. The design of QCL structures is performed by maximizing an objective function, i.e., $z_{{\rm UL}}^2 (1 - \tau _{\rm L} /\tau _{{\rm UL}} )\tau _{\rm U}$, related to the optical gain, including dipole matrix element ($z_{{\rm UL}}$) and population inversion between subbands. For a specific lasing wavelength, each barrier/well layer in the active region can be optimized to maximize the objective function, which results from the increase in the dipole matrix element and the reduction in the lifetime ratio of $\tau _{\rm L} /\tau _{{\rm UL}}$, by an iterative procedure. The optimized QCL structures are obtained for the target wavelengths from 11 to 12 µm by a step of 0.5 µm. For a QCL structure operating at λ = 11.98, it exhibits the maximized objection function of 6.30 ps‐nm2 with a large dipole matrix element under an electric field of 45 kV/cm. The influence of the percent variation of thickness in In0.53Ga0.47As and In0.52Al0.48As layers by the change in growth rate on the lasing wavelength and objective function is also investigated.
Photoluminescent properties of the monoclinic Ba2MgSi2O7:Eu2+ phosphor prepared by the combustion‐assisted synthesis method
Authors: Yao Shanshan , Li Yuanyuan , Xue Lihong , Yan Youwei
Published: May 2010

A blue–green emitting phosphor of the monoclinic Ba2MgSi2O7:Eu2+ was prepared by the combustion‐assisted synthesis method and an efficient bluish‐green emission under from ultraviolet to visible light was observed. The luminescence, crystallinity and particle sizes were investigated by using luminescence spectrometry, X‐ray diffractometry (XRD) and scanning electron microscopy (SEM). The emission spectrum shows a single intensive band centered at 498 nm, which corresponds to the 4f65d1 → 4f7 transition of Eu2+. The excitation spectrum is a broad extending from 260 to 465 nm, which matches the emission of ultraviolet light‐emitting diodes (UV‐LEDs). The critical quenching concentration of Eu2+ in Ba2MgSi2O7:Eu2+ phosphor is about 0.05 mol. The corresponding concentration quenching mechanism is verified to be a dipole–dipole interaction. The result indicates that Ba2MgSi2O7:Eu2+ can be potentially useful as a UV radiation‐converting phosphor for white light‐emitting diodes (LEDs).
Understanding colorations in PbMoO4 crystals through stoichiometric variations and annealing studies
Authors: Tyagi M. , Singh S. G. , Singh A. K. , Gadkari S. C.
Published: May 2010

In this paper, we report on PbMoO4 crystals grown from melts of controlled stoichiometric variations under different ambient conditions. It is observed that PbMoO4 crystals of different shades not only differ in their impurity contents but their stoichiometries with regard to both cationic and anionic compositions could be different. Annealing studies in air/oxygen as well as in vacuum were carried out on the crystals for a better understanding of the defect centers responsible for the coloration. The role of nonstoichiometric giving rise to coloration is also described.
Vacancy‐mediated room‐temperature ferromagnetism in Zn1−xMnxO thin films
Authors: Gopalakrishnan N. , Balakrishnan L. , Srimathy B. , Kumar M. Senthil , Balasubramanian T.
Published: May 2010

The effect of oxygen vacancies on ferromagnetism (FM) in Zn1−xMnxO thin films grown by radio frequency (RF) sputtering has been investigated. The grown films at different oxygen pressures have been characterized by X‐ray diffraction (XRD), Hall effect, photoluminescence (PL) and vibrating sample magnetometry (VSM). The observed ferromagnetism/diamagnetism by the VSM measurement due to the variation of oxygen vacancies has been confirmed by XRD, PL, and Hall results. The vacancy‐mediated FM has been explained by the formation of magnetic polarons.
Role of postannealing temperature on the microstructure of Al2O3/ZnO thin films grown by atomic layer deposition for TFT applications
Authors: Jang Yong Woon , Bang Seokhwan , Jeon Hyeongtag , Lee Jeong Yong
Published: May 2010

In this study, the effects of postannealing on ZnO and Al2O3 films grown for a thin‐film transistor (TFT) by the atomic layer deposition (ALD) method were examined using transmission electron microscopy (TEM) and energy‐dispersion spectroscopy. Samples were subjected to rapid thermal annealing for 30 s at 610, 615, 620, and 800 °C in a N2 atmosphere. At these temperatures, the polycrystalline ZnO layer in a TFT channel rapidly degraded to amorphous, and in the Al2O3 layer of a gate oxide layer of the TFT, a ZnAl2O4 spinel structure was formed because of Al and Zn diffusion. This spinel structure was observed to be independently nucleated, and there were no specific postgrowth crystallographic orientation relations. Additionally, in electrical properties of ZnO‐TFTs with ZnO/Al2O3 layers, typical TFT characteristics was shown until the annealing temperature increased to 600 °C, and the Vth gradually decreased from 4.2, 3 to 1.8 V. However, in the 700 °C annealed case, the TFT devices are always opened, and the ZnAl2O4 generation and the ZnO layer degradation was related to the drastic changes of these ZnO‐TFTs characteristics. During postannealing, rapid degradation of the ZnO channel layer and phase transformation by means of diffusion should be carefully considered.
Charge order quenching, Griffiths phase, and magnetotransport in polycrystalline Pr0.58Ca0.42−ySryMnO3 thin films
Authors: Agarwal Vasudha , Singh M. P. , Siwach P. K. , Fournier P. , Singh H. K.
Published: May 2010

We report the magneto‐electrical properties of polycrystalline Pr0.58Ca0.42−ySryMnO3 thin films as function of Sr doping (y). These films (thickness ∼300 nm) prepared by spray pyrolysis on LaAlO3 (100) single crystalline substrates are single phase and have orthorhombic structure. The Sr free films show charge ordering (CO) transition at TCO ≈ 240 K and the magnetic ground state has metamagnetic nature akin to the cluster glass (CG). Sr doping quenches CO and induces paramagnetic–ferromagnetic (PM–FM) transition with a systematic destabilization of the CG state. The PM–FM transition occurs at TC ≈ 182, 218, and 250 K for y = 0.06, 0.12, and 0.22, respectively. The Sr doping induced CO quenching also gives rise to the Griffiths phase (GP) at a temperature TG > TC. The resistivity of the Sr free films shows insulating behavior typical to the CO state. An insulator–metal transition (IMT) is observed at TIM ≈ 198 K in the y = 0.06 film, which increases to 225 and 265 K at y = 0.12 and 0.22, respectively. At y = 0.12, the sharpest IMT that results in huge temperature coefficient of resistivity (TCR) ≈19%, suggests the occurrence of a bicritical state. The bicriticality is also supported by a huge low field magnetoresistance ≈40% at 3 kOe and colossal magnetoresistance ≈90% at moderate magnetic field of 10 kOe. The destabilization of the CO, the appearance of GP, and the bicritical state has been explained in terms of the phase fluctuations induced by Sr doping dependent quenched disorder.
Preface: Phys. Status Solidi C 7/5
Authors: Kulik Tadeusz , Oleszak Dariusz
Published: May 2010

Every year in September, the European Materials Research Society organizes the Fall Meeting at War‐saw University of Technology. The 2009 Meeting was held from 14 to 18 September. This issue of physica status solidi contains proceedings of the Symposium H: Bulk Amorphous and Nanocrystalline Materials.

Amorphous and nanocrystalline alloys represent a unique group of materials exhibiting better or new properties in comparison with traditional polycrystal‐line materials. However, in many cases their applica‐tion is limited due to the small volume of the fabri‐cated alloys as a consequence of the technological processes. Recently, new types of alloys and new processing routes have appeared which enable the production of amorphous and nanocrystalline alloys and their composites in bulk form. They provide new technological potential for novel applications. The second main topic of the symposium was fabrication of bulk nanostructured materials by severe plastic de‐formation techniques. The symposium also highlighted advances in the development of nanoparticles with a special focus on fabrication methods, technologies and properties.

The symposium brought together researchers from various fields, including contributions from ma‐terials science and engineering, physics, chemistry, electronics and manufacturing.

We would like to take the opportunity to thank the Co‐Organizers of this symposium R. Yavari, J. Eckert and P. Svec. We also thank everyone in‐volved in the organization of this meeting: the Local Organizing Committee, the reviewers and especially all the participants whose contributions assured the high scientific level of this symposium (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tilt of InGaN layers on miscut GaN substrates
Authors: Kryśko M. , Domagala J. Z. , Czernecki R. , Leszczynski M. , Perlin P. , Suski T. , Grzanka Sz. , Targowski G. , Grzegory I. , Boćkowski M. , Porowski S.
Published: May 2010

We report on the crystallographic orientation of InGaN layers grown on GaN substrates with a miscut with respect to c ‐planes up to 2.5°. The samples were examined using high‐resolution X‐ray diffraction (HRXRD) and atomic force microscopy (AFM). Because of the large (up to about 2% in this study) lattice mismatch between InGaN and GaN, an additional tilt between the c lattice planes of InGaN and GaN was observed and explained by using the Nagai model [J. Appl. Phys. 45, 3789 (1974)]. We observed that for part of the samples, this tilt is about 10% smaller compared to the one predicted by the model. The experimental data are important for understanding the microstructure of InGaN layers grown on substrates of non‐perfect morphology. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The survival of glycine in interstellar ices: A coupled investigation using NEXAFS experiments and theoretical calculations
Authors: Lattelais M. , Risset O. , Pilme J. , Pauzat F. , Ellinger Y. , Sirotti F. , Silly M. , Parent Ph. , Laffon C.
Published: May 2010

Complex organic molecules have been observed in the interstellar medium in comets and meteorites. Among these compounds are the building blocks that may have led to prebiotic systems and ultimately to the origin of life. In the panspermia hypothesis, the survival and the transfer of the amino acids from space to planets is a necessary condition for the appearance of life, and, especially, their resistance to the solar UV radiation in ice is a key issue. The case of glycine, which is the smallest molecule in the amino acid family, is presented here. To improve our knowledge on the decomposition mechanisms of glycine, we have undertaken a coupled experimental and computational study. On the one hand, it has been performed a near‐edge X‐ray absorption spectroscopy (NEXAFS) study at the oxygen K‐edge of solid glycine and of glycine diluted into H2O ice, and irradiated at 30 K with soft X‐rays. However, extensive quantum chemical simulations using density functional theory have been realized at the B3LYP/cc‐pVQZ level. A systematic investigation of the most plausible fragmentations has been performed for neutral glycine itself, ionized glycine, doubly ionized glycine, protonated glycine, and zwitterionic glycine, the well known stable form of glycine trapped in ices. We show that glycine easily decomposes under irradiation. Water does not enhance or protect glycine from photodecomposition, but it increases the production of CO2 in the secondary photoreactions. The concentration of glycine tends to a limit of ∼30% of the initial load in the ice. The role of water ice appears to be that of a containment environment allowing the fragments to remain close, thus leading to reformation of glycine in situ. Under these conditions, it can be concluded that glycine is partially, but not entirely, protected by ice during its journey to the Earth. It is a strong point to be credited to the panspermia hypothesis. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Normalized mass mapping of Orbitrap data to define complex, polyglycerol‐based raw material compositions
Authors: Strife Robert J. , Mangels Michele L.
Published: May 2010

Kendrick Mass Mapping of complex sample compositions, via data derived by Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) at 1 000 000 resolution, is becoming more common. The Orbitrap mass spectrometer (Fourier Transform Axially Harmonic Orbital Trapping) also uses FT methods and indirect detection, though operating at a maximum resolution of 100 000. We define the more general case of Normalized Mass Mapping to any repeating oligomer unit (e.g., C3H6O2) and apply it to Orbitrap‐based mapping of a complex polyglycerol ester, 'green' raw material. Mass measurement errors showed sub‐ppm precision and accuracy in many cases, parameters that are critical to obtaining well‐defined maps. Map‐derived, raw‐material‐characterization parameters such as iodine value are compared with wet‐chemical results and show reasonable agreement for our purposes. The methodology appears applicable to raw material control and eliminates wet chemical methods. Copyright © 2010 John Wiley & Sons, Ltd.
The application of gas chromatography/atmospheric pressure chemical ionisation time‐of‐flight mass spectrometry to impurity identification in Pharmaceutical Development
Authors: Bristow Tony , Harrison Mark , Sims Martin
Published: May 2010

Accurate mass measurement (used to determine elemental formulae) is an essential tool for impurity identification in pharmaceutical development for process understanding. Accurate mass liquid chromatography/mass spectrometry (LC/MS) is used widely for these types of analyses; however, there are still many occasions when gas chromatography (GC)/MS is the appropriate technique. Therefore, the provision of robust technology to provide accurate mass GC/MS (and GC/MS/MS) for this type of activity is essential. In this report we describe the optimisation and application of a newly available atmospheric pressure chemical ionisation (APCI) interface to couple GC to time‐of‐flight (TOF) MS.

To fully test the potential of the new interface the APCI source conditions were optimised, using a number of standard compounds, with a variety of structures, as used in synthesis at AstraZeneca. These compounds were subsequently analysed by GC/APCI‐TOF MS. This study was carried out to evaluate the range of compounds that are amenable to analysis using this technique. The range of compounds that can be detected and characterised using the technique was found to be extremely broad and include apolar hydrocarbons such as toluene. Both protonated molecules ([M + H]+) and radical cations (M+.) were observed in the mass spectra produced by APCI, along with additional ion signals such as [M + H + O]+.

The technique has been successfully applied to the identification of impurities in reaction mixtures from organic synthesis in process development. A typical mass accuracy of 1–2 mm/zunits (m/z 80–500) was achieved allowing the reaction impurities to be identified based on their elemental formulae. These results clearly demonstrate the potential of the technique as a tool for problem solving and process understanding in pharmaceutical development. The reaction mixtures were also analysed by GC/electron ionisation (EI)‐MS and GC/chemical ionisation (CI)‐MS to understand the capability of GC/APCI‐MS relative to these two firmly established techniques. Copyright © 2010 John Wiley & Sons, Ltd.
Carbon isotope fractionation of benzene and toluene by progressive evaporation
Authors: Shin Woo‐Jin , Lee Kwang‐Sik
Published: May 2010

Evaporation is one of the key attenuation processes for near‐surface volatile organic compounds (VOCs) in the upper soil zone. Evaporation experiments were performed to investigate the carbon isotope fractionation of benzene and toluene during progressive and non‐equilibrium evaporation at room temperature. Considerable carbon isotope fractionation occurred during evaporative enrichment of benzene and toluene. The carbon isotope compositions of residual compounds increased exponentially with increasing evaporation. Thus, the remaining liquids become isotopically heavier, and the process follows a Rayleigh trend. This result is compatible with the direction of isotopic changes associated with both microbial degradation and volatilization of hydrocarbons previously observed in soil columns, but shows exactly the opposite behavior to previous equilibrium volatilization findings. Copyright © 2010 John Wiley & Sons, Ltd.
Identification of explosives and explosive formulations using laser electrospray mass spectrometry
Authors: Brady John J. , Judge Elizabeth J. , Levis Robert J.
Published: May 2010

Mass analysis is demonstrated for the detection of sub‐microgram quantities of explosive samples on a metallic surface at atmospheric pressure using laser electrospray mass spectrometry (LEMS). A non‐resonant femtosecond duration laser pulse vaporizes native samples for subsequent electrospray ionization and transfer into a time‐of‐flight mass spectrometer. LEMS was used to detect 2,3‐dimethyl‐2,3‐dinitrobutane (DMNB), 1,3,5‐trinitroperhydro‐1,3,5‐triazine (RDX), 3,4,8,9,12,13‐hexaoxa‐1,6‐diazabicyclo[4.4.4]tetradecane (HMTD), and 3,3,6,6,9,9‐hexamethyl‐1,2,4,5,7,8‐hexaoxacyclononane (TATP) deposited on a steel surface. LEMS was also used to directly analyze composite propellant materials containing an explosive to determine the molecular composition of the explosive pellets at atmospheric pressure. Copyright © 2010 John Wiley & Sons, Ltd.
A solvent‐free matrix application method for matrix‐assisted laser desorption/ionization imaging of small molecules
Authors: Goodwin R. J. , MacIntyre L. , Watson D. G. , Scullion S. P. , Pitt A. R.
Published: May 2010

Matrix application continues to be a critical step in sample preparation for matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI). Imaging of small molecules such as drugs and metabolites is particularly problematic because the commonly used washing steps to remove salts are usually omitted as they may also remove the analyte, and analyte spreading is more likely with conventional wet matrix application methods. We have developed a method which uses the application of matrix as a dry, finely divided powder, here referred to as dry matrix application, for the imaging of drug compounds. This appears to offer a complementary method to wet matrix application for the MALDI‐MSI of small molecules, with the alternative matrix application techniques producing different ion profiles, and allows the visualization of compounds not observed using wet matrix application methods. We demonstrate its value in imaging clozapine from rat kidney and 4‐bromophenyl‐1,4‐diazabicyclo(3.2.2)nonane‐4‐carboxylic acid from rat brain. In addition, exposure of the dry matrix coated sample to a saturated moist atmosphere appears to enhance the visualization of a different set of molecules. Copyright © 2010 John Wiley & Sons, Ltd.