bluuebunny/crossref_metadata_2025 huggingface dataset:
Epstein–Barr virus‐related lymphoproliferative disorder, cytomegalovirus reactivation, and varicella zoster virus encephalitis during treatment of medulloblastoma
Authors: Ohta Motoki , Taga Takashi , Nomura Akitaka , Kato Hirofumi , Takano Tomoyuki , Maruo Yoshihiro , Takeuchi Yoshihiro , Ishida Mitsuaki , Ohta Shigeru
Published: July 2011

The case of a 14‐year‐old girl who developed Epstein–Barr virus‐related lymphoproliferative disorder, cytomegalovirus reactivation, and Varicella zoster virus encephalitis during treatment for medulloblastoma is described. The patient was diagnosed with a cerebral medulloblastoma and treated with systemic chemotherapy, intrathecal chemotherapy, and radiotherapy. Six months later, she developed persistent low‐grade fever, abdominal pain, and vomiting. Several mucosal or ulcerated lesions of the stomach and colon were found on fiberscopy. The infiltrating cells were positive for CD20 and EBER1, and the diagnosis of lymphoproliferative disorder was made. CMV antigen was found in the peripheral lymphocytes at that time. At the same time, it was noted that the patient's language was inappropriate for her age, and a facial and abdominal rash, as well as a right facial palsy, had developed. She was then diagnosed as having VZV encephalitis, because VZV was detected in the CSF. She was treated subsequently with acyclovir and oral steroid, and the VZV encephalitis resolved. The lymphoproliferative disorder improved gradually with rituximab, ganciclovir, and total nutritional support. At the time of the development of the lymphoproliferative disorder and VZV encephalitis, the patient had severe lymphopenia and this may have caused these rare phenomena in a non‐transplant setting. J. Med. Virol. 83:1582–1584, 2011. © 2011 Wiley‐Liss, Inc.
Antiviral combination therapy with peginterferon and ribavirin does not induce a therapeutically resistant mutation in the HCV core region regardless of genetic polymorphism near the IL28B gene
Authors: Toyoda Hidenori , Kumada Takashi , Hayashi Kazuhiko , Honda Takashi , Katano Yoshiaki , Goto Hidemi , Kawaguchi Takahisa , Murakami Yoshiki , Matsuda Fumihiko
Published: July 2011

An association has been reported between genetic polymorphism near IL28B gene and the prevalence of mutation of hepatitis C virus (HCV) core region residue 70, both of which have been associated with a lack of virologic response to antiviral combination therapy with peginterferon (PEG‐IFN) and ribavirin. This study investigated whether PEG‐IFN/ribavirin combination therapy induces amino acid (AA) mutation at residue 70 of HCV and whether genetic polymorphism near IL28B gene affects it. AA substitutions at residue 70 of the HCV core region were measured and compared before and after combination therapy in 65 non‐responders and 88 relapsers to the combination therapy. In three patients in whom both wild‐type AA (arginine) and mutant‐type AA (glutamine or histidine) were detected at residue 70 before treatment, only mutant‐type AA was identified after treatment. In two patients who had wild‐type AA solely before treatment, both wild‐type and mutant‐type AAs were identified at residue 70 after treatment. In five patients, in whom the AA had changed at residue 70 between before and after treatment, four patients carried the TT genotype at a polymorphic locus (rs8099917) near the IL28B gene and one carried the TG/GG genotype. No difference was found in the prevalence of this change of AA at residue 70 between the TT and the TG/GG genotype. Antiviral combination therapy with PEG‐IFN and ribavirin does not appear to induce mutation of HCV core region residue 70 regardless of genetic polymorphism near the IL28B gene in Japanese patients infected with HCV genotype 1b. J. Med. Virol. 83:1559–1564, 2011. © 2011 Wiley‐Liss, Inc.
Development of chronic hepatitis B virus infection in hepatitis B surface antigen negative HIV/HBV co‐infected adults: A rare opportunistic illness
Authors: Landrum Michael L. , Roediger Mollie P. , Fieberg Ann M. , Weintrob Amy C. , Okulicz Jason F. , Crum‐Cianflone Nancy F. , Ganesan Anuradha , Lalani Tahaniyat , Macalino Grace E. , Chun Helen M.
Published: July 2011

Changes in serologic status in human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co‐infected individuals with either isolated anti‐HBc or resolved HBV infection have been reported, but the frequency of clinically meaningful long‐term serologic changes is not well‐defined. This study therefore, examined longitudinal serologic status for hepatitis B surface antigen (HBsAg)‐negative HIV/HBV co‐infected participants in a large cohort. Among 5,222 cohort participants, 347 (7%) were initially isolated anti‐HBc positive, and 1,073 (21%) had resolved HBV infection (concurrently reactive for anti‐HBc and anti‐HBs). Thirty‐three (10%) of the 347 participants with isolated anti‐HBc were later positive for HBsAg at least once, compared with 3 (0.3%) of those with resolved HBV (P < 0.001). A total of 14 participants became persistently positive for HBsAg and were thus classified as having late‐onset chronic HBV infection at a median of 3.7 years after initial HBV diagnosis. For those initially with HBsAg‐negative HIV/HBV co‐infection, the rate of late‐onset chronic HBV infection was 1.39/1,000 person‐years. Those with late‐onset chronic HBV infection experienced significant decreases in CD4 cell counts (P = 0.002) with a mean of 132 cells/µl at the time of late‐onset chronic HBV infection, but no factor distinguished those who were positive for HBsAg only once from those that developed late‐onset chronic HBV infection. Over a median of 2.9 years following late‐onset chronic HBV infection, 3 of 14 subsequently lost HBsAg. The occurrence of late‐onset chronic HBV infection in HBsAg negative HIV/HBV co‐infected adults appears to be one important, albeit rare, clinical event seen almost exclusively in those with isolated anti‐HBc and low CD4 cell count. J. Med. Virol. 83:1537–1543, 2011. © 2011 Wiley‐Liss, Inc.
Development and clinical validation of multiplex TaqMan® assays for rapid diagnosis of viral gastroenteritis
Authors: Feeney S.A. , Armstrong V.J. , Mitchell S.J. , Crawford L. , McCaughey C. , Coyle P.V.
Published: July 2011

There is a need to provide rapid, sensitive, and often high throughput detection of pathogens in diagnostic virology. Viral gastroenteritis is a serious health issue often leading to hospitalization in the young, the immunocompromised and the elderly. The common causes of viral gastroenteritis include rotavirus, norovirus (genogroups I and II), astrovirus, and group F adenoviruses (serotypes 40 and 41). This article describes the work‐up of two internally controlled multiplex, probe‐based PCR assays and reports on the clinical validation over a 3‐year period, March 2007 to February 2010. Multiplex assays were developed using a combination of TaqMan™ and minor groove binder (MGB™) hydrolysis probes. The assays were validated using a panel of 137 specimens, previously positive via a nested gel‐based assay. The assays had improved sensitivity for adenovirus, rotavirus, and norovirus (97.3% vs. 86.1%, 100% vs. 87.8%, and 95.1% vs. 79.5%, respectively) and also more specific for targets adenovirus, rotavirus, and norovirus (99% vs. 95.2%, 100% vs. 93.6%, and 97.9% vs. 92.3%, respectively). For the specimens tested, both assays had equal sensitivity and specificity for astrovirus (100%). Overall the probe‐based assays detected 16 more positive specimens than the nested gel‐based assay. Post‐introduction to the routine diagnostic service, a total of 9,846 specimens were processed with multiplex 1 and 2 (7,053 pediatric, 2,793 adult) over the 3‐year study period. This clinically validated, probe‐based multiplex testing algorithm allows highly sensitive and timely diagnosis of the four most prominent causes of viral gastroenteritis. J. Med. Virol. 83:1650–1656, 2011. © 2011 Wiley‐Liss, Inc.
Preparation of epoxy‐based macroporous monolithic columns for the fast and efficient immunofiltration of Staphylococcus aureus
Authors: Ott Sonja , Niessner Reinhard , Seidel Michael
Published: July 2011

Macroporous epoxy‐based monolithic columns were used for immunofiltration of bacteria. The prepared monolithic polymer support is hydrophilic and has large pore sizes of 21 μm without mesopores. A surface chemistry usually applied for immobilization of antibodies on glass slides is successfully transferred to monolithic columns. Step‐by‐step, the surface of the epoxy‐based monolith is hydrolyzed, silanized, coated with poly(ethylene glycol diamine) and activated with the homobifunctional crosslinker di(N‐succinimidyl)carbonate for immobilization of antibodies on the monolithic columns. The functionalization steps are characterized to ensure the coating of each monolayer. The prepared antibody‐immobilized monolithic column is optimized for immunofiltration to enrich Staphylococcus aureus as an important food contaminant. Different kinds of geometries of monolithic columns, flow rates and elution buffers are tested with the goal to get high recoveries in the shortest enrichment time as possible. An effective capture of S. aureus was achieved at a flow rate of 7.0 mL/min with low backpressures of 20.1±5.4 mbar enabling a volumetric enrichment of 1000 within 145 min. The bacteria were quantified by flow cytometry using a double‐labeling approach. After immunofiltration the sensitivity was significantly increased and a detection limit of the total system of 42 S. aureus/mL was reached.
Simultaneous determination of vinblastine and its monomeric precursors vindoline and catharanthine in Catharanthus roseus by capillary electrophoresis–mass spectrometry
Authors: Chen Qinhua , Li Na , Zhang Wenpeng , Chen Jing , Chen Zilin
Published: July 2011

Catharanthus roseus is an important dicotyledonous medicinal plant that contains various anticancer components, such as vinblastine (VLB) and its monomeric precursors (vindoline and catharanthine). A capillary electrophoresis–mass spectrometry (CE‐MS) approach for the simultaneous determination of three components was developed in this work. Baseline separation for three components was achieved by using a running buffer consisting of 20 mM ammonium acetate and 1.5% acetic acid in <20 min. Quantification of three components was assigned in positive‐ion mode at a protonated molecular ion [M+H]+. The CE‐MS method was validated for linearity, sensitivity, accuracy and precision, and then used to determine the content of the above components. The detection limits of VLB, catharanthine and vindoline are 0.8, 0.1 and 0.1 μg/mL, respectively. The precision was not more than 4.54% and the mean recovery of the analytes was 95.04–97.04%. The CE‐MS method was successfully applied to determine VLB and its monomeric precursors in real sample C. roseus.
Optimum conditions for the water extraction of L‐theanine from green tea
Authors: Vuong Quan V. , Stathopoulos Costas E. , Golding John B. , Nguyen Minh H. , Roach Paul D.
Published: July 2011

Theanine is a unique non‐protein amino acid found in tea (Camellia sinensis). It contributes to the favourable umami taste of tea and is linked to various beneficial effects in humans. There is an increasing interest in theanine as an important component of tea, as an ingredient for novel functional foods and as a dietary supplement. Therefore, optimal conditions for extracting theanine from tea are required for the accurate quantification of theanine in tea and as an efficient first step for its purification. This study examined the effects of four different extraction conditions on the yield of theanine from green tea using water and applied response surface methodology to further optimise the extraction conditions. The results showed that temperature, extraction time, ratio of water‐to‐tea and tea particle sizes had significant impacts on the extraction yield of theanine. The optimal conditions for extracting theanine from green tea using water were found to be extraction at 80°C for 30 min with a water‐to‐tea ratio of 20:1 mL/g and a tea particle size of 0.5–1 mm.
Enhanced Performance for Polymer Solar Cells by Using Surfactant‐Modified PEDOT:PSS as the Anode Buffer Layer
Authors: Fang Gang , Wu Shupeng , Xie Zhiyuan , Geng Yanhou , Wang Lixiang
Published: July 2011

The influence of the poly(3,4‐ethylene dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified with a kind of cationic surfactant, N,N,N‐trimethyl‐1‐hexadecanaminiu bromide (CTAB), on the above poly(3‐hexylthiophene) (P3HT), and [6,6]‐phenyl‐C6‐butyric acid methyl ester (PCBM) blend morphology and the performance of the resultant solar cells is investigated. The CTAB modification reduces the enrichment of insulating PSS on the top surface of the PEDOT:PSS layer and enhances the contact of conductive PEDOT in the PEDOT:PSS layer to the active layer. Moreover, the CTAB‐modified PEDOT:PSS layer favors P3HT crystallization and phase segregation with PCBM in the active layer. A 50% increase of power conversion efficiency is achieved for the solar cell with CTAB‐modified PEDOT:PSS instead of the commonly used PEDOT:PSS layer.

magnified image
Assessing the RAFT Equilibrium Constant via Model Systems: An EPR Study
Authors: Meiser Wibke , Buback Michael
Published: July 2011

Reversible addition‐fragmentation chain transfer (RAFT) equilibrium constants, Keq, for the model system cyano‐iso‐propyl dithiobenzoate (CPDB) – cyano‐iso‐propyl radical (CIP) have been deduced via electron paramagnetic reso1494nce (EPR) spectroscopy. The CIP species is produced by thermal decomposition of azobis‐iso‐butyronitrile (AIBN). In solution of toluene at 70 °C, Keq has been determined to be (9 ± 1) L · mol−1. Measurement of Keq = kad/kβ between 60 and 100 °C yields ΔEa = (–28 ± 4) kJ · mol−1 as the difference in the activation energies of kad and kβ. The data measured on the model system are indicative of fast fragmentation of the intermediate radical produced by addition of CIP to CPDB.

magnified image
Effects of Thermal Annealing Upon the Nanomorphology of Poly(3‐hexylselenophene)‐PCBM Blends
Authors: Lilliu Samuele , Agostinelli Tiziano , Verploegen Eric , Pires Ellis , Hampton Mark , Al‐Hashimi Mohammed , Heeney Martin J. , Toney Michael F. , Nelson Jenny , Macdonald J. Emyr
Published: July 2011

Grazing incidence X‐ray diffraction (GI‐XRD) is used to characterize the crystallographic dynamics of low molecular weight (LMW) and high molecular weight (HMW) poly(3‐hexylselenophene) (P3HS) films and blend films of P3HS with [6‐6‐]‐phenyl‐C61‐butyric acid methyl ester (PCBM) as a function of ‘step‐by‐step’ thermal annealing, from room temperature to 250 °C. The temperature‐dependent GIXRD data show how the melting point of P3HS crystallites is decreased by the presence of PCBM. P3HS crystallite domain sizes dramatically increase upon annealing to the P3HS melting temperature. The formation of well‐oriented HMW P3HS crystallites with the (100) plane parallel to the substrate (edge‐on orientation), when cooled from melt, are observed. We compare the behaviour of P3HS pure and blend films with that of poly(3‐hexyl)thiophene (P3HT) pure and PCBM blended films and suggest that the similar temperature dependent behaviour we observe may be a common to polythiophene and related polymers and their blends.

magnified image
MicroRNAs, diet, and cancer: New mechanistic insights on the epigenetic actions of phytochemicals
Authors: Parasramka Mansi A. , Ho Emily , Williams David E. , Dashwood Roderick H.
Published: July 2011

There is growing interest in the epigenetic mechanisms that impact human health and disease, including the role of microRNAs (miRNAs). These small (18–25 nucleotide), evolutionarily conserved, non‐coding RNA molecules regulate gene expression in a post‐transcriptional manner. Several well‐orchestered regulatory mechanisms involving miRNAs have been identified, with the potential to target multiple signaling pathways dysregulated in cancer. Since the initial discovery of miRNAs, there has been progress towards therapeutic applications, and several natural and synthetic chemopreventive agents also have been evaluated as modulators of miRNA expression in different cancer types. This review summarizes the most up‐to‐date information related to miRNA biogenesis, and critically evaluates proposed miRNA regulatory mechanisms in relation to cancer signaling pathways, as well as other epigenetic modifications (DNA methylation patterns, histone marks) and their involvement in drug resistance. We also discuss the mechanisms by which dietary factors regulate miRNA expression, in the context of chemoprevention versus therapy. © 2011 Wiley Periodicals, Inc.
Subthalamic nucleus deep brain stimulation restores normal rapid eye movement sleep in Parkinson's disease
Authors: Nishida Namiko , Murakami Tokiko , Kadoh Kunihiro , Tohge Rie , Yamanegi Miki , Saiki Hidemoto , Ueda Keita , Matsumoto Sadayuki , Ishikawa Masatsune , Takahashi Jun A. , Toda Hiroki
Published: July 2011

Background:

In Parkinson's disease, sleep disturbance is a common occurrence.

Methods:

We evaluated sleep in 10 patients with Parkinson's disease (age, 57.5 ± 9.8 years; disease duration, 12.3 ± 2.7 years) before and after subthalamic nucleus deep brain stimulation using the Parkinson's disease sleep scale and polysomnography.

Results:

Their total sleep scale scores and daytime sleepiness subscale scores significantly improved after subthalamic nucleus‐deep brain stimulation. The novel findings from this study significantly increased normal rapid eye movement sleep, and decreased abnormal rapid eye movement sleep without atonia after deep brain stimulation in patients with Parkinson's disease. The improved total sleep scale score correlated with decreased wakefulness after sleep onset. Moreover, improved daytime sleepiness correlated with increased normal rapid eye movement sleep time. Sleep improvement did not significantly correlate with resolution of motor complication or reduced dopaminergic dosages.

Conclusions:

Subthalamic nucleus‐deep brain stimulation may have beneficial effects on sleep disturbance in advanced Parkinson's disease by restoring sleep architecture and normal rapid eye movement sleep. © 2011 Movement Disorder Society
Advanced MudPIT as a next step toward high proteome coverage
Authors: Fränzel Benjamin , Wolters Dirk A.
Published: July 2011

We present a simple, time‐ and cost‐efficient approach to tackle the proteome of prokaryotic organisms. To obtain large data sets of complex biological experiments high‐throughput and time‐ and cost‐efficient methods still have to be developed and refined. In this study, we combined well‐approved techniques, namely elevated chromatographic temperatures, long RP columns and the multidimensional protein identification technology MudPIT to achieve high proteome coverage. The advanced MudPIT approach has been evaluated and delivered very comprehensive results for Gram‐positive as well as Gram‐negative bacteria (53% proteome coverage for Corynebacterium glutamicum and 46% proteome coverage for Escherichia coli). Also, a high identification rate for the challenging integral membrane proteins was achieved. The competitiveness of the advanced MudPIT technology is strengthened by the fact that in this approach only two fractions were analyzed with both, simple and time‐efficient sample preparation, and a moderate data acquisition time.
Significantly improved photovoltaic performances of the dithiophene‐benzothiadiazole‐alt‐fluorene copolymers by incorporating carbazole units in fluorene moiety
Authors: Liu Ming , Wang Yafei , Zhang Zhiyong , Li Jianming , Liu Yu , Tan Hua , Ni Meijun , Lei Gangtie , Zhu Meixiang , Zhu Weiguo
Published: July 2011

To exploit an effective way to improve polymeric photovoltaic performance, a series of dithiophene‐benzothiadiazole‐alt‐fluorene copolymers containing carbazole groups at C‐9 positions of the alternating fluorene units (PFO‐FCz‐DBT) were synthesized and characterized. The effect of the carbazole groups on the optophysical, electrochemical, and photovoltaic properties of these copolymers was investigated. By comparison, this type of copolymers with carbazole units exhibited significantly improved photovoltaic properties than poly(2,7‐(9,9‐dioctyl‐fluorene)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole) (PFO‐DBT) in the bulk heterojunction solar cells. A maximum power‐conversion efficiency (PCE) of 2.41% and a highest short‐circuit current density (Jsc) of 9.68 mA cm−2 were obtained for the PFO‐FCz‐DBT30, which are about two times higher than the corresponding levels for the PFO‐DBT30. This work demonstrated that introducing a hole‐transporting carbazole unit into copolymer is a simple and effective method to improve the Jsc and PCE. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of high molecular weight polymer nanoparticles by [Cp2ZrCl2] catalyzed emulsion polymerization
Authors: De Sudip K. , Bhattacharjee Manish
Published: July 2011

An early transition metal metallocene compound, Cp2ZrCl2, with an anionic surfactant, sodium n‐dodecyl sulfate (SDS) as emulsifier and NaBPh4 as cocatalyst has been found to be an effective catalytic system for polymerization and copolymerization of monomers like styrene and methyl methacrylate in aqueous medium. The diameters of the latex particles were found to be in between 20 and 40 nm. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and self‐assembly of novel amphiphilic copolymers poly(lactic acid)‐block‐poly(ascorbyl acrylate)
Authors: Wang Yanzhai , Yang Junjiao , Yang Jing
Published: July 2011

In this study, a novel type of amphiphilic block copolymers poly(lactic acid)‐block‐poly(ascorbyl acrylate) (PLA‐block‐PAAA) with biodegradable poly(lactic acid) as hydrophobic block and poly(ascorbyl acrylate) (PAAA) as hydrophilic block was successfully developed by a combination of ring‐opening polymerization and atom transfer radical polymerization, followed by hydrogenation under normal pressure. The chemical structures of the desired copolymers were characterized by 1H NMR and gel permeation chromatography. The thermal physical properties and crystallinity were investigated by thermogravimetric analysis, differential scanning calorimetry, and wide angle X‐ray diffraction, respectively. Their self‐assembly behavior was monitored by fluorescence‐probe technique and turbidity change using UV–vis spectrometer, and the morphology and size of the nanocarriers via self‐assembly were detected by cryo‐transmission electron microscopy and dynamic light scattering. These polymeric micelles with PAAA shell extending into the aqueous solution have potential abilities to act as promising nanovehicles for targeting drug delivery. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Characterization of resulting network polymer precursors in stepwise crosslinking diepoxide/diamine polymerization
Authors: Matsumoto Akira , Kaneda Yujiro , Aota Hiroyuki
Published: July 2011

Our previous mechanistic discussion of network formation in chainwise crosslinking multiallyl polymerization was extended to stepwise crosslinking diepoxide/diamine polymerization, typically including bisphenol‐A diglycidyl ether (BADGE) and 4,4′‐diaminodiphenylmethane (DDM). In allyl polymerization a monomer chain transfer is an essential termination reaction, providing only oligomeric primary polymer chains. Therefore, crosslinking multiallyl polymerization could be in the category of a classical gelation theory. Thus, the gelation behavior was discussed by comparing the actual gel point with the theoretical one. Then the resulting network polymer precursors (NPPs) were characterized by size‐exclusion chromatography‐multiangle laser light scattering‐viscometry to clarify the stepwise crosslinking BADGE/DDM polymerization mechanism. Notably, the intrinsic viscosity ratio [η]NPP/[η]Linear tended to decrease with the progress of crosslinking and finally, it reached less than 0.2. This suggests that the structure of resulting NPP becomes dendritic at a conversion close to the gel point. These dendritic NPPs can collide with each other to form crosslinks between NPPs, eventually leading to gelation as a reflection of the high concentration of NPP. The dilution effect on gelation was marked in polar solvent; no gelation was observed at a dilution of 1/5. However, in nonpolar solvent the gelation was promoted by dilution; this is ascribed to enhanced crosslink formation between NPPs through hydrogen bonding due to abundant hydroxyl groups in the NPP generated by the polyaddition reaction. Finally, the subject of “Is cured epoxy resin inhomogeneous?” is briefly discussed. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis of well‐defined pH‐responsive PPEGMEA‐g‐P2VP double hydrophilic graft copolymer via sequential SET‐LRP and ATRP
Authors: Zhai Sujuan , Song Xuemei , Yang Dong , Chen Wulian , Hu Jianhua , Lu Guolin , Huang Xiaoyu
Published: July 2011

A series of well‐defined double hydrophilic graft copolymers containing poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMEA) backbone and poly(2‐vinylpyridine) (P2VP) side chains were synthesized by successive single electron transfer living radical polymerization (SET‐LRP) and atom transfer radical polymerization (ATRP). The backbone was first prepared by SET‐LRP of poly(ethylene glycol) methyl ether acrylate (PEGMEA) macromonomer using CuBr/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained homopolymer then reacted with lithium diisopropylamide and 2‐chloropropionyl chloride at −78 °C to afford PPEGMEA‐Cl macroinitiator. poly(poly(ethylene glycol) methyl ether acrylate)‐g‐poly(2‐vinylpyridine) double hydrophilic graft copolymers were finally synthesized by. ATRP of 2‐vinylpyridine initiated by PPEGMEA‐Cl macroinitiator at 25 °C using CuCl/hexamethyldiethylenetriamine as catalytic system via the grafting‐ from strategy. The molecular weights of both the backbone and the side chains were controllable and the molecular weight distributions kept relatively narrow (Mw/Mn ≤ 1.40). pH‐Responsive micellization behavior was investigated by 1H NMR, dynamic light scattering, and transmission electron microscopy and this kind of double hydrophilic graft copolymer aggregated to form micelles with P2VP‐core while pH of the aqueous solution was above 5.0. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Electro‐optical properties of electropolymerized poly(3‐hexylthiophene)/carbon nanotube composite thin films
Authors: Patel Romesh J. , Tighe Timothy B. , Ivanov Ilia N. , Hickner Michael A.
Published: July 2011

3‐hexylthiophene was electropolymerized on a carbon nanotube (CNT)‐laden fluorine‐doped tin oxide substrate. Scanning electron microscopy and Raman spectroscopy revealed that the polymer was infused throughout the thickness of the 150‐nm thick CNT mat, resulting in a conducting composite film with a dense CNT network. The electropolymerized poly(3‐hexylthiophene) (e‐P3HT)/CNT composites exhibited photoluminescence intensity quenching by as much as 92% compared to the neat e‐P3HT, which provided evidence of charge transfer from the polymer phase to the CNT phase. Through‐film impedance and J‐V measurements of the composites gave a conductivity (σ) of 1.2 × 10−10 S cm−1 and zero‐field mobility (μ0) of 8.5 × 10−4 cm2 V−1 s−1, both of which were higher than those of neat e‐P3HT films (σ = 9.9 × 10−12 S cm−1, μ0 = 3 × 10−5 cm2 V−1 s−1). In electropolymerized samples, the thiophene rings were oriented in the (010) direction (thiophene rings parallel to substrate), which resulted in a broader optical absorbance than for spin coated samples, however, the lack of long‐range conjugation caused a blueshift in the absorbance maximum from 523 nm for unannealed regioregular P3HT (rr‐P3HT) to 470 nm for e‐P3HT. Raman spectroscopy revealed that π‐π stacking in e‐P3HT was comparable to that in rr‐P3HT and significantly higher than in regiorandom P3HT (ran‐P3HT) as shown by the principal Raman peak shift from 1444 to 1446 cm−1 for e‐P3HT and rr‐P3HT to 1473 cm−1 for ran‐P3HT. This work demonstrates that these polymer/CNT composites may have interesting properties for electro‐optical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1269–1275, 2011
The oligomeric state of the truncated mechanosensitive channel of large conductance shows no variance in vivo
Authors: Iscla Irene , Wray Robin , Blount Paul
Published: July 2011

The mechanosensitive channel of large conductance (MscL) from E. coli serves as an emergency release valve allowing the cell to survive acute osmotic downshock. It is one of the best studied mechanosensitive channels and serves as a paradigm for how a protein can sense and respond to membrane tension. Two MscL crystal structures of the orthologs M. tuberculosis and S. aureus have been solved showing pentameric and tetrameric structures, respectively. Several studies followed to understand whether the discrepancy in their stoichiometry was a species difference or a consequence of the protein manipulation for crystallization. Two independent studies now agree that the full‐length S. aureus MscL is actually a pentamer, not tetramer. While detergents appear to play a role in modifying the oligomeric state of the protein, a cytoplasmic helical bundle has also been implicated. Here, we evaluate the role of the C‐terminal region of S. aureus MscL in the oligomerization of the channel in native membranes by using an in vivo disulfide‐trapping technique. We find that the oligomeric state of S. aureus MscLs with different C‐terminal truncations, including the one used to obtain the tetrameric S. aureus MscL crystal structure, are pentamers in vivo. Thus, the C‐terminal domain of the S. aureus protein only plays a critical role in the oligomeric state of the SaMscL protein when it is solubilized in detergent.
Extent of enthalpy–entropy compensation in protein–ligand interactions
Authors: Olsson Tjelvar S. G. , Ladbury John E. , Pitt Will R. , Williams Mark A.
Published: July 2011

The extent of enthalpy–entropy compensation in protein–ligand interactions has long been disputed because negatively correlated enthalpy (ΔH) and entropy (TΔS) changes can arise from constraints imposed by experimental and analytical procedures as well as through a physical compensation mechanism. To distinguish these possibilities, we have created quantitative models of the effects of experimental constraints on isothermal titration calorimetry (ITC) measurements. These constraints are found to obscure any compensation that may be present in common data representations and regression analyses (e.g., in ΔH vs. –TΔS plots). However, transforming the thermodynamic data into ΔΔ‐plots of the differences between all pairs of ligands that bind each protein diminishes the influence of experimental constraints and representational bias. Statistical analysis of data from 32 diverse proteins shows a significant and widespread tendency to compensation. ΔΔH versus ΔΔG plots reveal a wide variation in the extent of compensation for different ligand modifications. While strong compensation (ΔΔH and −TΔΔS opposed and differing by < 20% in magnitude) is observed for 22% of modifications (twice that expected without compensation), 15% of modifications result in reinforcement (ΔΔH and −TΔΔS of the same sign). Because both enthalpy and entropy changes arise from changes to the distribution of energy states on binding, there is a general theoretical expectation of compensated behavior. However, prior theoretical studies have focussed on explaining a stronger tendency to compensation than actually found here. These results, showing strong but imperfect compensation, will act as a benchmark for future theoretical models of the thermodynamic consequences of ligand modification.
Altered prostate epithelial development in mice lacking the androgen receptor in stromal fibroblasts
Authors: Yu Shengqiang , Yeh Chiuan‐Ren , Niu Yuanjie , Chang Hong‐Chiang , Tsai Yu‐Chieh , Moses Harold L , Shyr Chih‐Rong , Chang Chawnshang , Yeh Shuyuan
Published: July 2011

BACKGROUND

Androgens and the androgen receptor (AR) play important roles in the development of male urogenital organs. We previously found that mice with total AR knockout (ARKO) and epithelial ARKO failed to develop normal prostate with loss of differentiation. We have recently knocked out AR gene in smooth muscle cells and found the reduced luminal infolding and IGF‐1 production in the mouse prostate. However, AR roles of stromal fibroblasts in prostate development remain unclear.

METHODS

To further probe the stromal fibroblast AR roles in prostate development, we generated tissue‐selective knockout mice with the AR gene deleted in stromal fibroblasts (FSP‐ARKO). We also used primary culture stromal cells to confirm the in vivo data and investigate mechanisms related to prostate development.

RESULTS

The results showed cellular alterations in the FSP‐ARKO mouse prostate with decreased epithelial proliferation, increased apoptosis, and decreased collagen composition. Further mechanistic studies demonstrated that FSP‐ARKO mice have defects in the expression of prostate stromal growth factors. To further confirm these in vivo findings, we prepared primary cultured mouse prostate stromal cells and found knocking down the stromal AR could result in growth retardation of prostate stromal cells and co‐cultured prostate epithelial cells, as well as decrease of some stromal growth factors.

CONCLUSIONS

Our FSP‐ARKO mice not only provide the first in vivo evidence in Cre‐loxP knockout system for the requirement of stromal fibroblast AR to maintain the normal development of the prostate, but may also suggest the selective knockdown of stromal AR might become a potential therapeutic approach to battle prostate hyperplasia and cancer. Prostate 72:437–449, 2012. © 2011 Wiley Periodicals, Inc.
Raman spectroscopic investigation of phase separation and compositional fluctuations in nanocrystalline InxGa1−xN thin films prepared by modified activated reactive evaporation
Authors: Meher S. R. , Biju K. P. , Jain M. K.
Published: July 2011

Nano‐crystalline c‐axis oriented InxGa1−xN (x = 0.93, 0.63, 0.5, 0.36 and 0.18) thin films were prepared by modified activated reactive evaporation technique. Phase segregation was clearly observed for x = 0.5 composition. Scanning electron microscopy images reveal the average grain size for all the films to be varying from 40 to 85 nm. From, the absorption spectra the band gaps for the InGaN films were found to be varying from 1.89 to 2.92 eV. Micro‐Raman scattering at two different excitation energies (1.96 and 2.54 eV) were used to study the phase separation and compositional fluctuations of InGaN layers across their thickness. All the spectra exhibit the characteristic A1(LO) and E2 (high) modes corresponding to hexagonal wurtzite structure for both the excitations. No appreciable change in the peak positions for the two excitations confirms the absence of any significant phase separation across the thickness of InGaN films with x = 0.36 and 0.18 composition. However, for x = 0.93 and 0.63 films, gallium rich minority phase could be detected with 1.96 eV excitation. The changes in the area and FWHM of the two characteristic Raman peaks for different excitations are attributed to the increased structural defects across the sample depth and also to the near resonance effects.
Effects of annealing on the structural and photoluminescence properties of Zn0.98Cr0.02O thin films prepared by magnetron sputtering
Authors: Fu C. F. , Han L. F. , Liu C.
Published: July 2011

Cr‐doped ZnO thin films have been prepared on silicon substrates by magnetron sputtering method. The effects of annealing on the compositions, crystallographic structures, and optical properties of the thin films are systematically investigated by energy dispersive spectroscopy, X‐ray diffraction, and photoluminescence, respectively. The results show that the intensity of ZnO(002) peak firstly increases and then decreases with increasing the annealing temperature, whereas the full width at half maximum and the stress firstly decrease and then increase with the annealing temperature increasing. The higher crystallization quality and minimum stress was found for the samples annealed at 600 °C in oxygen ambient. It is also found from the photoluminescence spectra that the ultraviolet emission peak and green emission band are located at 380 nm and 500 nm, respectively. Further investigations indicate that the nature of the green emission is connected with the concentration of oxygen vacancies. In addition, the excellent luminescence performance of Cr‐doped ZnO thin films can be obtained by high temperature annealing at 600 °C in oxygen ambient, which can make green emission weakened gradually and even disappeared.
Dislocation reactions in hetero‐epitaxial (0001) GaN layers
Authors: Meng F. Y. , Mahajan S.
Published: July 2011

Dislocation reactions in hetero‐epitaxial GaN layers grown on (0001) sapphire were analyzed using weak beam dark field technique in transmission electron microscopy. Examples of the four basic reactions were observed. The average capture radius of the reactions was estimated from these observations.
Local structure determination of the nonlinear optical material LiNbO3using XRD
Authors: Saravanan R. , Thirumalaisamy T. K. , Kajitani T.
Published: July 2011

The ultimate crystal and electronic structure will give complete information of nonlinear materials for their potential applications. The electron density distribution and local structure of the nonlinear optical material LiNbO3have been studied and analyzed. Powder X‐ray data of LiNbO3is analyzed in terms of local structure. The bonding between the atoms has been studied using maximum entropy method and the bond‐length distribution using pair distribution function. The three‐dimensional, two‐dimensional electron density maps, and one‐dimensional electron density profiles have been constructed and analyzed. The particle size of LiNbO3has been analyzed using X‐ray diffractometer and SEM. The band gap energy has also been calculated using UV–visible absorption spectra.
Magnetic properties of exchange‐spring composite films
Authors: Kronmüller Helmut , Goll Dagmar
Published: July 2011

High‐density magnetic recording in the Tbit/inch2 range is based on single bit, single domain particles in the nanometer range. In order to fulfil the prerequisites for high‐density recording the following magnetic properties must be guaranteed: Easy axis perpendicular to recording plane, thermal stability up to 200 °C, reversal fields of 1–2 T and switching times in the sub‐ns range. Composite nanoparticles composed of a soft and a hard magnetic layer are suitable to fulfil the above conditions. The magnetic ground states of exchange coupled bilayers are determined by micromagnetism and the corresponding reversal fields determined as a function of the soft magnetic film thickness. It is shown that the magnetic ground states are characterized by three configurations: in‐plane, oblique, and perpendicular magnetization depending on the thickness of the soft magnetic layer. These three ground states are characterized by reversal fields of different magnetization processes: Depinning of a charged Néel wall at the phase boundary for soft layer thicknesses Ls larger than the exchange length of the soft layer, spontaneous rotation of magnetization by a nucleation process for soft layer thicknesses smaller than the exchange length.
Antimicrobial Potential of Australian Macrofungi Extracts Against Foodborne and Other Pathogens
Authors: Bala Neeraj , Aitken Elizabeth A. B. , Cusack Andrew , Steadman Kathryn J.
Published: July 2011

Basidiomycetous macrofungi have therapeutic potential due to antimicrobial activity but little information is available for Australian macrofungi. Therefore, the present study investigated 12 Australian basidiomycetous macrofungi, previously shown to have promising activity against Staphylococcus aureus and Escherichia coli, for their antimicrobial potential against a range of other clinically relevant micro‐organisms. Fruiting bodies were collected from across Queensland, Australia, freeze‐dried and sequentially extracted with water and ethanol. The crude extracts were tested at 10 mg/mL and 1 mg/mL against six pathogens including two Gram‐positive and two Gram‐negative bacteria along with two fungi using a high throughput 96‐well microplate bioassay. A degree of specificity in activity was exhibited by the water extract of Ramaria sp. (Gomphaceae) and the ethanol extracts of Psathyrella sp. (Psathyrellaceae) and Hohenbuehelia sp., which inhibited the growth of the two fungal pathogens used in the assay. Similarly, the ethanol extract of Fomitopsis lilacinogilva (Fomitopsidaceae) was active against the Gram‐positive bacteria B. cereus only. Activity against a wider range of the microorganisms used in the assay was exhibited by the ethanol extract of Ramaria sp. and the water extract of Hohenbuehelia sp. (Pleurotaceae). These macrofungi can serve as new sources for the discovery and development of much needed new antimicrobials. Copyright © 2011 John Wiley & Sons, Ltd.
Atmospheric conservation properties in ERA‐Interim
Authors: Berrisford P. , Kållberg P. , Kobayashi S. , Dee D. , Uppala S. , Simmons A. J. , Poli P. , Sato H.
Published: July 2011

We study the global atmospheric budgets of mass, moisture, energy and angular momentum in the latest reanalysis from the European Centre for Medium‐Range Weather Forecasts (ECMWF), ERA‐Interim, for the period 1989–2008 and compare with ERA‐40. Most of the measures we use indicate that the ERA‐Interim reanalysis is superior in quality to ERA‐40. In ERA‐Interim the standard deviation of the monthly mean global dry mass of 0.7 kg m−2 (0.007%) is slightly worse than in ERA‐40, and long time‐scale variations in dry mass originate predominately in the surface pressure field. The divergent winds are improved in ERA‐Interim: the global standard deviation of the time‐averaged dry mass budget residual is 10 kg m−2 day−1 and the quality of the cross‐equatorial mass fluxes is improved. The temporal variations in the global evaporation minus precipitation (E − P) are too large but the global moisture budget residual is 0.003 kg m−2 day−1 with a spatial standard deviation of 0.3 kg m−2 day−1. Both the E − P over ocean and P − E over land are about 15% larger than the 1.1 Tg s−1 transport of water from ocean to land. The top of atmosphere (TOA) net energy losses are improved, with a value of 1 W m−2, but the meridional gradient of the TOA net energy flux is smaller than that from the Clouds and the Earth's Radiant Energy System (CERES) data. At the surface the global energy losses are worse, with a value of 7 W m−2. Over land however, the energy loss is only 0.5 W m−2. The downwelling thermal radiation at the surface in ERA‐Interim of 341 W m−2 is towards the higher end of previous estimates. The global mass‐adjusted energy budget residual is 8 W m−2 with a spatial standard deviation of 11 W m−2, and the mass‐adjusted atmospheric energy transport from low to high latitudes (the sum for the two hemispheres) is 9.5 PW. Copyright © 2011 Royal Meteorological Society
Investigation of preparation techniques for δ2H analysis of keratin materials and a proposed analytical protocol
Authors: Qi Haiping , Coplen Tyler B.
Published: July 2011

Accurate hydrogen isotopic measurements of keratin materials have been a challenge due to exchangeable hydrogen in the sample matrix and the paucity of appropriate isotopic reference materials for calibration. We found that the most reproducible δ2HVSMOW‐SLAP and mole fraction of exchangeable hydrogen, x(H)ex, of keratin materials were measured with equilibration at ambient temperature using two desiccators and two different equilibration waters with two sets of the keratin materials for 6 days. Following equilibration, drying the keratin materials in a vacuum oven for 4 days at 60 °C was most critical. The δ2H analysis protocol also includes interspersing isotopic reference waters in silver tubes among samples in the carousel of a thermal conversion elemental analyzer (TC/EA) reduction unit. Using this analytical protocol, δ2HVSMOW‐SLAP values of the non‐exchangeable fractions of USGS42 and USGS43 human‐hair isotopic reference materials were determined to be –78.5 ± 2.3 ‰ and –50.3 ± 2.8 ‰, respectively. The measured x(H)ex values of keratin materials analyzed with steam equilibration and N2 drying were substantially higher than those previously published, and dry N2 purging was unable to remove absorbed moisture completely, even with overnight purging. The δ2H values of keratin materials measured with steam equilibration were about 10 ‰ lower than values determined with equilibration in desiccators at ambient temperatures when on‐line evacuation was used to dry samples. With steam equilibrations the x(H)ex of commercial keratin powder was as high as 28 %. Using human‐hair isotopic reference materials to calibrate other keratin materials, such as hoof or horn, can introduce bias in δ2H measurements because the amount of absorbed water and the x(H)ex values may differ from those of unknown samples. Correct δ2HVSMOW‐SLAP values of the non‐exchangeable fractions of unknown human‐hair samples can be determined with atmospheric moisture equilibration by normalizing with USGS42 and USGS43 human‐hair reference materials when all materials have the same powder size. Copyright © 2011 John Wiley & Sons, Ltd.
The relevance of facilitation in group decision making supported by a simulation model
Authors: Borštnar Mirjana Kljajić , Kljajić Miroljub , Škraba Andrej , Kofjač Davorin , Rajkovič Vladislav
Published: July 2011

This paper addresses the impact of feedback information and facilitation on a decision‐making process supported by a system dynamics model. We conducted the Solomon Four‐Group Experiment under four conditions: (a1) interrupted individual determination of a strategy supported by a simulation model and a facilitator; (a2) interrupted individual determination of a strategy supported by a simulation model and a facilitator plus group information feedback (GIF); (a3) continuous individual determination of a strategy supported by a simulation model; and (a4) continuous individual determination of a strategy supported by a simulation model plus GIF. The observed variables were criteria function (CF), frequency of simulation runs (FSR), and insight into GIF. The hypotheses that a simulation model supports individual learning and additional GIF contributes to faster learning were confirmed. The importance of the facilitator and structure of feedback information was demonstrated and a model explaining learning in the decision process was developed. Copyright © 2011 System Dynamics Society.
Analysing antibody response based on data obtained from serial dilution methods
Authors: Chan Linda S. , Overturf Gary D. , Selzer Jeffrey
Published: July 2011

We identify several problem areas in statistical analyses of data obtained from serial dilution methods in serology. We provide the mathematical backgrounds of the key elements involved in this field of study and discuss the statistical considerations. The problem areas include the use of the geometric mean as an expression of the average of a set of observations, the use of fold increase to measure antibody response, and the statistical analysis of the change in antibody response with respect to other variables, such as age and pretiter levels.
Adjusting proportional mortality ratios for the influence of extraneous causes of death
Authors: McDowall Michael
Published: July 2011

Proportional mortality ratios (PMRs) are frequently used where denominators of the population at risk are not available or are known to be seriously biased. The interpretation of proportional measures requires care and can be complicated by the fact that a PMR of a cause of interest may be affected by disproportionate mortality from one or more other causes of death. This problem is examined using occupational mortality data for England and Wales. A method of allowing for the influence of other causes of death on a PMR of interest is proposed and it is argued that this approach is a useful aid to the general interpretation of PMRs.