bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blue Laser Diodes
Authors: Piprek Joachim 
Published: March 2011

AbstractThe first demonstration of a GaN‐based blue laser diode by Shuji Nakamura [1] was followed by a tremendous research and development effort around the world. Gallium nitride technology enables a range of novel applications with vast consumer markets. Examples are full‐color video displays, solid‐state lighting, and high‐definition DVD players. However, there still remains a strong need for a more detailed understanding of microscopic physical processes in nitride devices. Advanced models and numerical simulation can help to investigate those processes and to improve the device performance. This article reviews practical examples of GaN‐laser simulation, analysis, and optimization [2, 3].
Investigation of photo‐oxidative effect on morphology and degradation of mechanical and physical properties of nano CaCO3 silicone rubber composites
Authors: Mishra Satyendra , Shimpi Navinchandra G , Mali Ananda D 
Published: March 2011

AbstractPhoto‐oxidative degradation of treated and untreated nano CaCO3: silicone rubber composite was studied under accelerated UV irradiation (≥290 nm) at different time intervals. Prolonged exposure to UV leads to a progressive decrease in mechanical and physical properties along with the change in behavior of filler‐matrix interaction. This was due to decrease in cross‐linking density with increase in mobility of rubber chains. Meanwhile, synthesized nano CaCO3 was modified with stearic acid for uniform dispersion in rubber matrix. The increase in carbonyl (>CO), hydroxyl (OH), CO2, and alkene functional groups on the UV exposed surface of treated and untreated nano CaCO3: silicone rubber composites at different time intervals was studied using Fourier transform infrared (FTIR) spectroscopy. The change in morphological behavior of filler‐matrix interaction after UV exposure was studied using SEM. Overall, the study showed that the treated nano CaCO3: silicone composites were affected more by UV exposure than untreated nano CaCO3: silicone composites and pristine composite after UV exposure. This effect was due to peeling of stearic acid from the surface of CaCO3, which makes the rubber chains slippery and thus separation of filler and rubber chains takes place with initiation of fast‐degradation. Copyright © 2011 John Wiley & Sons, Ltd.
Role of GLI2 in the growth of human osteosarcoma
Authors: Nagao Hiroko , Ijiri Kosei , Hirotsu Masataka , Ishidou Yasuhiro , Yamamoto Takuya , Nagano Satoshi , Takizawa Takumi , Nakashima Kinichi , Komiya Setsuro , Setoguchi Takao 
Published: March 2011

AbstractThe Hedgehog pathway functions as an organizer in embryonic development. Aberrant activation of the Hedgehog pathway has been reported in various types of malignant tumours. The GLI2 transcription factor is a key mediator of Hedgehog pathway but its contribution to neoplasia is poorly understood. To establish the role of GLI2 in osteosarcoma, we examined its expression by real‐time PCR using biopsy tissues. To examine the function of GLI2, we evaluated the growth of osteosarcoma cells and their cell cycle after GLI2 knockdown. To study the effect of GLI2 activation, we examined mesenchymal stem cell growth and the cell cycle after forced expression of GLI2. We found that GLI2 was aberrantly over‐expressed in human osteosarcoma biopsy specimens. GLI2 knockdown by RNA interferences prevented osteosarcoma growth and anchorage‐independent growth. Knockdown of GLI2 promoted the arrest of osteosarcoma cells in G1 phase and was accompanied by reduced protein expression of the cell cycle accelerators cyclin D1, SKP2 and phosphorylated Rb. On the other hand, knockdown of GLI2 increased the expression of p21cip1. In addition, over‐expression of GLI2 promoted mesenchymal stem cell proliferation and accelerated their cell cycle progression. Finally, evaluation of mouse xenograft models showed that GLI2 knockdown inhibited the growth of osteosarcoma in nude mice. Our findings suggest that inhibition of GLI2 may represent an effective therapeutic approach for patients with osteosarcoma. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Mutation of PPP2R1A: a new clue in unveiling the pathogenesis of uterine serous carcinoma
Authors: Shih Ie‐Ming , Wang Tian‐Li 
Published: March 2011

AbstractUterine carcinoma is composed mainly of two distinct types: serous and endometrioid. Uterine serous carcinoma, while not as common as endometrioid carcinoma, is a highly aggressive disease and is associated with high mortality. Although the molecular genetic alterations of uterine endometrioid carcinoma have been well established, molecular genetic changes in uterine serous carcinoma are largely unclear. Two recent papers have analysed PPP2R1A mutations among different types of gynaecological neoplasia. Both studies report a surprisingly high frequency of somatic mutations of PPP2R1A in uterine serous carcinomas. PPP2R1A encodes a scaffolding subunit of a major serine/threonine phosphatase, protein phosphatase 2A (PP2A), which plays a critical role in diverse cellular functions, including negative regulation of cellular proliferation and potential tumour suppression. As PPP2R1A is essential for the phosphatase activity of PP2A, this observation should create a new research road map toward elucidating how PPP2R1A mutations and alterations of the PP2A pathway contribute to the pathogenesis of uterine serous carcinoma. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.Invited commentary for McConechy M K et al. Subtype‐specific mutation of PPP2R1A in endometrial and ovarian carcinomas. Journal of Pathology. 2011; 223: 567–573. http://dx.doi.org/10.1002/path.2848
First trimester maternal serum PAPP‐A and free β‐HCG levels in hyperemesis gravidarum
Authors: Derbent Aysel Uysal , Yanik Filiz Fatma , Simavli Serap , Atasoy Latife , Ürün Emel , Kuşçu Ülkü Esra , Turhan Nilgün Öztürk 
Published: March 2011

AbstractObjectiveTo evaluate whether hyperemesis gravidarum (HG) affects first‐trimester maternal serum PAPP‐A and free β‐hCG levels.MethodAn observational study was conducted in 115 cases of HG and 110 control pregnancies who attended the first‐trimester prenatal screening program between January 2006 and July 2010.ResultsMaternal serum TSH levels were lower and free T4, and transaminases (ALT, AST) levels were higher in pregnancies complicated with HG compared with controls (p < 0.05 for all). In HG cases, median values of maternal serum PAPP‐A were significantly higher with respect to normal pregnancies (1.2 vs 1.0 MoM; p = 0.009). Similarly, median values of free β‐hCG were 1.3 MoM in HG pregnancies and 1.0 MoM in controls (p = 0.006). Multivariate analysis revealed that PAPP‐A and hCG were independently associated with HG after controlling for TSH, free T4, AST, and ALT.ConclusionHG is associated with elevated levels of PAPP‐A and free β‐hCG, and such changes are independent of serum indicators of thyroid and liver function. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation of the antifungal properties of chitosan coating on cut apples using a non‐invasive image analysis technique
Authors: Garrido Assis Odilio B , de Britto Douglas 
Published: March 2011

AbstractImage analysis techniques have often been chosen as fundamental tools for evaluating the surface and/or structure of organic and inorganic materials over a broad range of scales. In the study reported, a simple image capture system comprising a commercial desktop scanner combined with free image analysis software was used to evaluate the efficiency of antifungal activity of commercial medium‐molecular‐weight chitosan as an edible coating on sliced apples. Fungal growth rate (predominantly Penicillium sp. and Alternaria sp.) was assessed via images acquired twice daily and binary‐transformed for quantitative analysis. The inhibitory effect of chitosan coating on the mycelial fungi growth on cut apple surfaces was confirmed. Chitosan deposited on glass slides was used to simulate film formation and its structure was characterized using atomic force microscopy, revealing a thin porous formation. Copyright © 2011 Society of Chemical Industry
Die Licht(r)evolution. Weiße LEDs für die Allgemeinbeleuchtung
Authors: Kölper Christopher , Bergbauer Werner , Straßburg Martin , Linder Norbert 
Published: March 2011

AbstractLeuchtdioden (LEDs) glänzen durch lange Lebensdauer, gute Farbwiedergabe, schnelle Einschaltzeit und Dimmbarkeit. Das macht sie zunehmend attraktiv für die Allgemeinbeleuchtung. Vor allem benötigen sie weniger Energie als konventionelle Leuchtmittel. Als Materialsysteme haben sich AlInGaN und AlInGaP etabliert, die Lichtfarben in einem breiten Spektralbereich ermöglichen. Nur für grünes Licht gibt es noch kein effizientes LED‐Material. Der dafür nötige hohe Indiumgehalt im geeigneteren AlInGaN sorgt für fehlerhafte Kristallgitter, was die Effizienz senkt. Nanostrukturen könnten das Problem lösen. Für weiße Leuchtdioden haben sich verschiedene Verfahren etabliert. Gängig ist die Kombination einer blauen LED mit einem Leuchtstoff, der einen Teil ihres Lichts ins Gelbe konvertiert. LEDs haben ein großes Potenzial zur weiteren Steigerung ihrer Effizienz und Helligkeit. Sie werden schon bald in vielen Bereichen konventionelle Technologien ablösen.
Bose‐Einstein‐Kondensat aus Licht
Authors: Klaers Jan , Schmitt Julian , Vewinger Frank , Weitz Martin 
Published: March 2011

AbstractBose‐Einstein‐Kondensate (BEC) stellen einen Zustand von Quantengasen dar, den Satyendra Nath Bose und Albert Einstein in den 1920er Jahren für ein Gas von idealen Bosonen vorausgesagt haben. In einem BEC verhalten sich die Teilchen im Grundzustand wie ein einzelnes “Superteilchen.” Dies wurde erstmals 1995 mit atomaren Gasen realisiert, die auf Temperaturen im Nanokelvinbereich gekühlt wurden (Phys. Unserer Zeit 1996, 27 (5), 200 und 2003, 34 (4), 168). Seitdem gab es viele weitere Experimente mit verschiedenen bosonischen Teilchen, lediglich mit dem wohl bekanntesten Vertreter, dem Photon, ließ sich bislang kein BEC herstellen. Dies gelang kürzlich unserer Gruppe an der Universität Bonn.
Synthesis, characterization, and electrochemical studies of new 5‐ and 6‐nitro N‐acyl‐1H‐indazoles
Authors: Recabarren‐Gajardo G. , Gacitúa M. , Murueva I. , Romero J. , Espinosa‐Bustos C. , Mella‐Raipán J. , del Valle M. A. , Pessoa‐Mahana C. D. , Tapia R. 
Published: March 2011

AbstractTwo series of new N‐1 acylindazoles containing 5‐ or 6‐nitro groups were synthesized with moderate to good yields and characterized by IR and NMR spectroscopy. Cyclic voltammetry in aprotic media was utilized for the electrochemical characterization of the compounds. The calculated reduction potentials in physiological conditions are similar to those of known commercial antichagasic drugs. Therefore, the novel series reported herein are prospective candidates for antichagasic biological evaluation. Theoretical calculation results indicate that the studied dinitro derivatives undergo a single step reduction process because of the energy proximity of their radical and anionic state. Copyright © 2011 John Wiley & Sons, Ltd.
Conformational analysis of 4,4‐dimethyl‐4‐silathiane and its S‐oxides
Authors: Shainyan Bagrat A. , Suslova Elena N. , Kleinpeter Erich 
Published: March 2011

Abstract4,4‐Dimethyl‐4‐silathiane and its S‐oxides [n = 0 (1), 1 (2), 2 (3)] were studied experimentally by variable temperature dynamic NMR spectroscopy down to 103 K and the frozen ring inversion was revealed for all three compounds. The barriers for the degenerate ring inversion in 1 and 3 were measured to be 4.8 and 5.0 kcal/mol at the coalescence temperatures of 111 and 116 K, respectively, and practically coincide with the calculated barriers of 4.60 kcal/mol in 1 and 4.46 kcal/mol in 3. The frozen equilibrium mixture 2‐ax/2‐eq contains 37% of the 2‐ax and 63% of the 2‐eq conformer. The ring inversion barrier proved to be ca. 4.8 kcal/mol. Calculations at the B3LYP/6‐311+G(d,p) level of theory showed the 2‐ax conformer to be 0.90 kcal/mol more stable than the 2‐eq conformer in the gas phase whereas in solution the relative stability of the conformers calculated using the PCM model at the same level of theory is inverted to become 0.19 (in CHCl3) or 0.36 kcal/mol (in DMSO) in favor of the 2‐eq conformer. The chair–chair interconversion mechanism of sulfoxide 2 includes two intermediate energetically equivalent 1,4‐twist forms and the 2,5‐boat transition state: 2‐ax (chair) ⇆ 2 (1,4‐twist) ⇆ [2 (2,5‐boat)]≠ ⇆ 2 (1,4‐twist) ⇆ 2‐eq (chair). The calculated ring inversion barriers are 5.1 (2‐ax → 2‐eq) and 4.2 kcal/mol (2‐eq → 2‐ax) in the gas phase, and 4.03 and 4.22 kcal/mol, respectively, in chloroform. Copyright © 2011 John Wiley & Sons, Ltd.
Thiol‐ene clickable hyperscaffolds bearing peripheral allyl groups
Authors: Roy Raj Kumar , Ramakrishnan S. 
Published: March 2011

AbstractRadical catalyzed thiol‐ene reaction has become a useful alternative to the Huisgen‐type click reaction as it helps to expand the variability in reaction conditions as well as the range of clickable entities. Thus, direct generation of hyperbranched polymers bearing peripheral allyl groups that could be clicked using a variety of functional thiols would be of immense value. A specifically designed AB2 type monomer, that carries two allyl benzyl ethers groups and one alcohol functionality, was shown to undergo self‐condensation under acid‐catalyzed melt‐transetherification to yield a hyperbranched polyether that carries numerous allyl end‐groups. Importantly, it was shown that the kinetics of polymerization is not dramatically affected by the change of the ether unit from previously studied methyl benzyl ether to an allyl benzyl ether. The peripheral allyl groups were readily clicked quantitatively, using a variety of thiols, to generate an hydrocarbon‐soluble octadecyl‐derivative, amphiphilic systems using 2‐mercaptoethanol and chiral amino acid (N‐benzoyl cystine) derivatized hyperbranched structures; thus demonstrating the versatility of this novel class of clickable hyperscaffolds. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Syntheses of terminally functionalized polyisobutylene derivatives using diazonium salts
Authors: Bergbreiter David E. , Priyadarshani Nilusha 
Published: March 2011

AbstractA new strategy for the synthesis of end‐functionalized polyisobutylene (PIB) oligomers is detailed. Commercially available vinyl‐terminated PIB oligomers were modified to form aniline‐terminated PIB via an aromatic electrophilic substitution reaction. The PIB‐bound aryl amines so formed were then converted into diazonium salts using isopentyl nitrite and an acid in methylene chloride. These salts served as versatile intermediates in synthetic reactions affording azo dye‐containing PIB derivatives and other terminally‐functionalized PIB derivatives not readily available by other reactions. The advantages and limitations of various name reactions including diazo couplings, Sandmeyer reactions, dediazoniations, and Heck reactions are discussed. The kinetics of polar substitution reactions at the termini of these nonpolar oligomers and the effects of solvent on these reactions were also examined. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and nonlinear optical properties of novel Y‐type polyester containing tricyanovinylthiazolylazoresorcinoxy group with enhanced thermal stability of dipole alignment
Authors: Cho You Jin , No Hyo Jin , Kim Mi Sung , Lee Ju‐Yeon 
Published: March 2011

AbstractNovel Y‐type polyester 4 containing 5‐methyl‐4‐{5‐(1,2,2‐tricyanovinyl)‐2‐thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which are parts of the polymer backbone, was prepared, and its NLO properties were investigated. Polyester 4 is soluble in common organic solvents such as N,N‐dimethylformamide and dimethylsulfoxide. Polymer 4 shows a thermal stability up to 250 °C from thermogravimetric analysis with glass‐transition temperature obtained from differential scanning calorimetry of approximately 94 °C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at 1560‐nm fundamental wavelength is 8.12 × 10−9 esu. The dipole alignment exhibits a thermal stability even at 6 °C higher than glass‐transition temperature (Tg), and no significant SHG decay is observed below 100 °C due to the partial main‐chain character of polymer structure, which is acceptable for NLO device applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis, characterization, and ethylene (Co)polymerization behavior of trichlorotitanium 2‐(1‐(arylimino)propyl)quinolin‐8‐olates
Authors: Huang Wei , Zhang Wenjuan , Liu Shaofeng , Liang Tongling , Sun Wen‐Hua 
Published: March 2011

AbstractA series of trichlorotitanium complexes containing 2‐(1‐(arylimino)propyl)quinolin‐8‐olates was synthesized by stoichiometric reaction of titanium tetrachloride with the corresponding potassium 2‐(1‐(arylimino)propyl)quinolin‐8‐olates and was fully characterized by elemental analysis, nuclear magnetic resonance spectroscopy, and by single‐crystal X‐ray diffraction study of representative complexes. All titanium complexes, when activated with methylaluminoxane, exhibited high catalytic activity toward ethylene polymerization [up to 1.15 × 106 g mol−1(Ti) h−1] and ethylene/α‐olefin copolymerization [up to 1.54 × 106 g mol−1 (Ti) h−1]. The incorporation of comonomer was confirmed to amount up to 2.82 mol % of 1‐hexene or 1.94 mol % of 1‐octene, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Chiral crystal of a C2v‐symmetric 1,3‐diazaaulene derivative showing efficient optical second harmonic generation
Authors: Ma Xiao‐Hua , Fu Li‐Min , Zhao Yunfeng , Ai Xi‐Cheng , Zhang Jian‐Ping , Han Yu , Guo Zhi‐Xin 
Published: March 2011

AbstractAchiral nonlinear optical (NLO) chromophores 1,3‐diazaazulene derivatives, 2‐(4′‐aminophenyl)‐6‐nitro‐1,3‐diazaazulene (APNA) and 2‐(4′‐N,N‐diphenylaminophenyl)‐6‐nitro‐1,3‐diazaazulene (DPAPNA), were synthesized with high yield. Despite the moderate static first hyperpolarizabilities (β0) for both APNA [(136 ± 5) × 10−30 esu] and DPAPNA [(263 ± 20) × 10−30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown that the APNA crystallization driven cooperatively by the strong H‐bonding network and the dipolar electrostatic interactions falls into the noncentrosymmetric P212121 space group, and that the helical supramolecular assembly is solely responsible for the efficient SHG response. To the contrary, the DPAPNA crystal with centrosymmetric P‐1 space group is packed with antiparalleling dimmers, and is therefore completely SHG‐inactive. 1,3‐Diazaazulene derivatives are suggested to be potent building blocks for SHG‐active chiral crystals, which are advantageous in high thermal stability, excellent near‐infrared transparency and high degree of designing flexibility. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Cloud point suppression in dilute solutions of model gradient copolymers with prespecified composition profiles
Authors: Gallow Keith C. , Jhon Young K. , Tang Wei , Genzer Jan , Loo Yueh‐Lin 
Published: March 2011

AbstractGradient copolymers of 2‐hydroxyethyl methacrylate (HEMA) and 2‐(dimethylamino)ethyl methacrylate (DMAEMA) having prescribed linear, parabolic, and hyperbolic composition profiles were synthesized with the guidance of a numerical model that determines the instantaneous comonomer feed rate. These materials exhibit low polydispersity indices (<1.1); the evolution of the overall DMAEMA content and the absolute molecular weight of the copolymers are all in good agreement with the quantities predicted by our model. Compared to random copolymers of HEMA and DMAEMA, the cloud points of dilute buffered aqueous solutions of gradient copolymers decrease with increasing gradient strength; where the gradient strength is defined as the largest difference in the instantaneous composition along the copolymer. The temperature range over which the solutions transition from transparent to turbid also broadens significantly with increasing gradient strength. Both observations suggest the onset of transition to be dictated by the least soluble ends of the polymer chains. These correlations point to the importance of monomer sequence distribution in determining the macroscopic physical properties of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Multiaxial deformation of polyethylene and polyethylene/clay nanocomposites: in situ synchrotron small angle and wide angle X‐ray scattering study
Authors: Gurun Bilge , Bucknall David G. , Thio Yonathan S. , Teoh Chin Ching , Harkin‐Jones Eileen 
Published: March 2011

AbstractA unique in situ multiaxial deformation device has been designed and built specifically for simultaneous synchrotron small angle X‐ray scattering (SAXS) and wide angle X‐ray scattering (WAXS) measurements. SAXS and WAXS patterns of high‐density polyethylene (HDPE) and HDPE/clay nanocomposites were measured in real time during in situ multiaxial deformation at room temperature and at 55 °C. It was observed that the morphological evolution of polyethylene is affected by the existence of clay platelets as well as the deformation temperature and strain rate. Martensitic transformation of orthorhombic into monoclinic crystal phases was observed under strain in HDPE, which is delayed and hindered in the presence of clay nanoplatelets. From the SAXS measurements, it was observed that the thickness of the interlamellar amorphous region increased with increasing strain, which is due to elongation of the amorphous chains. The increase in amorphous layer thickness is slightly higher for the nanocomposites compared to the neat polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
The impact of breast cancer on mother–child relationships in Korea
Authors: Kim Sue , Ko Yun Hee , Jun Eun Young 
Published: March 2011

AbstractObjectiveFor families with dependent children, the situational crisis of a cancer diagnosis may compound the developmental task of parenting. This study aimed to explore the impact of breast cancer on Korean mothers and their children following diagnosis.MethodsKorean women diagnosed with breast cancer at 50 years or younger more than a year ago were recruited by posting announcements at a breast cancer clinic and through referrals and snowball sampling. A one‐time in‐depth interview ranging from 60 to 90 min was conducted and data were transcribed verbatim for content analysis.ResultsFive themes emerged from the data: (1) The delicate balance of being able to focus on self, which also was a conflicting factor in their relationship with children; (2) The continuing challenge of taking care of children, which was closely linked to supports, health condition, and cultural notions of parenting and lingering stigma; (3) The importance of informing children in a timely manner; (4) An overall shift in attitudes towards raising children as independent beings; and (5) Relinquishing and re‐envisioning the future for their children and themselves.ConclusionsBreast cancer brings new challenges in mother–child relationships with culturally framed issues. Findings can guide healthcare providers in giving relevant anticipatory guidance for women diagnosed with breast cancer and in considering family‐focused psychosocial and behavioral interventions for families with breast cancer.Copyright © 2011 John Wiley & Sons, Ltd.
Hydrodynamics of holographic flavored plasmas
Authors: Bigazzi F. , Cotrone A.L. , Tarrío J. 
Published: March 2011

AbstractWe provide a short review of the hydrodynamical properties of a class of strongly coupled thermal gauge theories, coupled to massless fundamental flavor fields, having a dual supergravity description. The analysis is valid for more general classes of nearly conformal holographic plasmas, where the breaking of conformality is driven by marginally (ir)relevant deformations.