bluuebunny/crossref_metadata_2025 huggingface dataset:
Individual patient data meta‐analysis of time‐to‐event outcomes: one‐stage versus two‐stage approaches for estimating the hazard ratio under a random effects model
Authors: Bowden Jack , Tierney Jayne F , Simmonds Mark , Copas Andrew J , Higgins Julian PT
Published: January 2012

Meta‐analyses of individual patient data (IPD) provide a strong and authoritative basis for evidence synthesis. IPD are particularly useful when the outcome of interest is the time to an event. Methodological developments now enable the meta‐analysis of time‐to‐event IPD using a single model, allowing treatment effect and across‐trial heterogeneity parameters to be estimated simultaneously. This differs from the standard approaches used with aggregate data, and also predominantly with IPD. Facilitated by a simulation study, we investigate what these new ‘one‐stage’ random‐effects models offer over standard ‘two‐stage’ approaches. We find that two‐stage approaches represent a robust, reliable and easily implementable way to estimate treatment effects and account for heterogeneity. Nevertheless, one‐stage models can be used to provide a deeper insight into the data. Software for fitting one‐stage Cox models with random effects using Restricted Maximum Likelihood methodology is made available, and its use demonstrated on an IPD meta‐analysis assessing post‐operative radio therapy for patients with non‐small cell lung cancer. Copyright © 2011 John Wiley & Sons, Ltd.
Arginine‐rich coconut kernel diet influences nitric oxide synthase activity in alloxandiabetic rats
Authors: Salil Gopalakrishnan , Nevin Kottayath G. , Rajamohan Thankappan
Published: January 2012

BACKGROUND: Coconut kernel protein (CKP) has been reported to contain significant amounts of L‐arginine. Its potential effect on glucose homeostasis, possibly through the nitric oxide synthase (NO) pathway, was therefore investigated in alloxan‐induced diabetic rats. Diabetes was induced by a single intraperitoneal dose of alloxan (150 mg kg−1 body weight). Experimental rats were grouped as follows: Group I, normal control; Group II, diabetic control; Group III, diabetic + CKP; Group IV, diabetic + L‐arginine; Group V, diabetic + L‐arginine + L‐NG‐Nitroarginine methyl ester (L‐NAME). Purified CKP isolated from dried coconut kernel and L‐arginine was administered to rats along with a semi‐synthetic diet for 45 days. L‐NAME (0.5 mg kg−1 body weight) was given to Group V animals. After the experimental period, serum glucose, insulin, activities of liver nitric oxide synthase and arginase, liver glycogen levels and histopathology of the pancreas were evaluated.

RESULTS: Serum glucose, insulin and antioxidant enzyme activities and liver glycogen levels were found to be restored to basal levels in CKP‐fed rats. Decreased arginase and increased nitric oxide synthase (NOS) activities were found in CKP‐ and arginine‐fed rats. L‐NAME treatment showed a partial effect on these parameters. Histopathology revealed that CKP and L‐arginine feeding reduced the diabetes‐related pancreatic damage in treated rats compared to the diabetic control.

CONCLUSION: The results observed in this study indicate that the potential antidiabetic activity of CKP may be through an arginine‐NO pathway leading to pancreatic beta cell regeneration. Copyright © 2012 Society of Chemical Industry
Abnormal expression of E‐cadherin in tumor cells is associated with poor prognosis of gastric carcinoma
Authors: Li Yin , Chen Chuang‐Qi , He Yu‐Long , Cai Shi‐Rong , Yang Dong‐Jie , He Wei‐Ling , Xu Jian‐Bo , Zan Wen‐Hua
Published: January 2012

Background and Objectives

The purpose of this study was to clarify the relationship of hepatocyte growth factor (HGF), c‐Met, and E‐cadherin with clinicopathological parameters and prognosis in gastric carcinoma (GC).

Methods

114 specimens were collected from GC patients and expression of HGF, c‐Met, and E‐cadherin in tissue microarray was evaluated by immunohistochemical staining. Correlation between immunostainings and clinicopathological parameters, follow‐up data of patients, was analyzed statistically.

Results

Abnormal E‐cadherin expression was found in 60.5% (69/114) and associated with tumor depth (P = 0.003), lymph node metastasis (P = 0.001) and advanced clinical stage (P = 0.001). High‐expression of HGF and c‐Met were found in 64.0% (73/114) and 82.4% (94/114), respectively. High c‐Met expression was significantly associated with advanced clinical stage (P = 0.001) and lymph node metastasis (P = 0.011) of GC. In univariate survival analysis, high‐expression of HGF and c‐Met, and abnormal E‐cadherin were significantly associated with poor prognosis of GC patients. However, only abnormal E‐cadherin expression (P = 0.001) and tumor depth (P = 0.010) emerged as strong independent prognostic factors for overall survival of GC patients.

Conclusion

We found significant correlation among HGF/c‐Met, E‐cadherin expression and worse prognosis of patients with GC. Abnormal E‐cadherin expression may serve as an independent predictive factor for prognosis of GC patients. J. Surg. Oncol. 2012; 106:304–310. © 2012 Wiley Periodicals, Inc.
Kinetics of Collapse Transition and Cluster Formation in a Thermoresponsive Micellar Solution of P(S‐b‐NIPAM‐b‐S) Induced by a Temperature Jump
Authors: Adelsberger Joseph , Metwalli Ezzeldin , Diethert Alexander , Grillo Isabelle , Bivigou‐Koumba Achille M. , Laschewsky André , Müller‐Buschbaum Peter , Papadakis Christine M.
Published: January 2012

Structural changes at the intra‐ as well as intermicellar level were induced by the LCST‐type collapse transition of poly(N‐isopropyl acrylamide) in ABA triblock copolymer micelles in water. The distinct process kinetics was followed in situ and in real‐time using time‐resolved small‐angle neutron scattering (SANS), while a micellar solution of a triblock copolymer, consisting of two short deuterated polystyrene endblocks and a long thermoresponsive poly(N‐isopropyl acrylamide) middle block, was heated rapidly above its cloud point. A very fast collapse together with a multistep aggregation behavior is observed. The findings of the transition occurring at several size and time levels may have implications for the design and application of such thermoresponsive self‐assembled systems.
Synthesis of Main‐Chain Metallo‐Copolymers Containing Donor and Acceptor Bis‐Terpyridyl Ligands for Photovoltaic Applications
Authors: Padhy Harihara , Ramesh Mohan , Patra Dhananjaya , Satapathy Rudrakanta , Pola Murali Krishna , Chu Hsuan‐Chih , Chu Chih‐Wei , Wei Kung‐Hwa , Lin Hong‐Cheu
Published: January 2012

Two random (ZnII‐based P1–P2) and two alternating (RuII‐based P3–P4) metallo‐copolymers containing bis‐terpyridyl ligands with various central donor (i.e., fluorene or carbazole) and acceptor (i.e., benzothiadiazole) moieties were synthesized. The effects of electron donor–acceptor interactions with metal (ZnII and RuII) ions on their thermal, optical, and electrochemical properties were investigated. Because of the strong ICT transitions between donor and acceptor ligands in both ZnII‐ and RuII‐based metallo‐coplymers and MLCT transitions in RuII‐based metallo‐coplymers, the absorption spectra covered a broad range of 260–750 nm with the band gaps of 1.57–1.77 eV. In addition, the introduction of RuII‐based metallo‐coplymer P4 mixed with PC60BM as an active layer of the BHJ solar cell device exhibited the highest PCE value up to 0.90%.
Living Polymerization via Anionic Initiation for the Synthesis of Well‐Defined PPV Materials
Authors: Cosemans Inge , Wouters Jimmy , Cleij Thomas , Lutsen Laurence , Maes Wouter , Junkers Tanja , Vanderzande Dirk
Published: January 2012

The anionic polymerization of PPV via the sulfinyl precursor route is further investigated. When LHMDS is employed as the base to form the actively propagating quinodimethane system and THF as the solvent, anionic polymerizations can be observed. With the use of tert‐ butyl‐substituted anionic initiators, specific functional groups can be built in the polymer chain and the chain length can be efficiently controlled, which is demonstrated here for the first time. With introduction of branched side chains on the aromatic core, soluble conjugated PPV material can be obtained with molecular weights in the range of 5000–16 000 g mol−1.
Nonsymmetric Black Box multigrid with coarsening by three
Authors: Yavneh Irad , Weinzierl Marion
Published: January 2012

The classical Petrov–Galerkin approach to Black Box multigrid for nonsymmetric problems due to Dendy is combined with the recent factor‐three‐coarsening Black Box algorithm due to Dendy and Moulton, along with a powerful symmetric line Gauss–Seidel smoother, resulting in an efficient and robust multigrid solver. Focusing on the convection–diffusion operator, the algorithm is tested and shown to achieve fast and reliable convergence with both first‐order and second‐order accurate upstream discretizations of the convection operator. The solver also exhibits robust behavior with respect to discontinuous jumps in the diffusion coefficient and performs well for recirculating flows over a wide range of diffusion coefficients. The efficiency of the solver is supported by results of an analysis for the case of constant coefficients. Copyright © 2012 John Wiley & Sons, Ltd.
Antibiotic prescribing trends in a paediatric sub‐population in Ireland
Authors: Keogh C , Motterlini N , Reulbach U , Bennett K , Fahey T
Published: January 2012

Purpose

Little is known about antibiotic prescribing in Irish children. This study aims to examine antibiotic prescribing patterns in Irish children and associated costs and to compare this with European findings.

Methods

A retrospective analysis of the Irish Health Services Executive (HSE) pharmacy claims database 2004–2009 for the General Medical Services (GMS) scheme for dispensed medications. This represents 28% of Irish children but over‐represents lower socio‐economic groups. Overall prescribing rates were reported over time (2004–2009), age (0–4, 5–11, 12–15 years) and gender. Statistical comparison is made using negative binomial regression. Overall prescribing rates for the most commonly prescribed drugs were calculated. Associated cost of prescribing also was calculated. European prescribing data were retrieved from the literature.

Results

Rates remained stable from 2004 (631/1000 GMS population; 95%CI 628–634) to 2009 (621/1000; 95%CI 618–624). An interaction effect emerged between gender and age. Rates were generally higher for girls, except for the boys aged 0–4 years. The preferred choice of agents changed across years, with co‐amoxiclav becoming the most prescribed drug in 2009 (308/1000; 95%CI 306–310). The total cost of antibiotics increased from €4.4 million in 2004 to €6.0 million in 2009. Higher overall rates of antibiotic prescribing emerged compared with available European data. Differences were observed between prescribing of some first‐line and second‐line drugs.

Conclusions

Age and gender trends are consistent with international literature. However, Ireland has higher overall prescribing rates relative to some European countries. This suggests that a quality improvement in prescribing intervention is warranted. Copyright © 2012 John Wiley & Sons, Ltd.
Parental trust in health care—a prospective study from the Children's Cancer Hospital in Egypt
Authors: El Malla Hanan , Kreicbergs Ulrika , Steineck Gunnar , Wilderäng Ulrica , El Sayed Elborai Yasser , Ylitalo Nathalie
Published: January 2012

Objective

Patient–physician communication and patient satisfaction are important elements of cancer care. Trust is considered to be crucial for the patient–physician relationship, yet little is to be found in the literature regarding what factors may influence trust.

Methods

We assessed predictors of trust in health‐care professionals and in the medical care by administering two questionnaires, one at start of chemotherapy treatment and one at the time of the third chemotherapy cycle, to 304 parents of children with newly diagnosed cancer at the Children's Cancer Hospital in Cairo, Egypt.

Results

Parents' trust in the medical care at the time of the child's third chemotherapy cycle was significantly associated with the following at the start of treatment: having received at least moderate information about the disease (relative risk (RR) 13.2; 95% CI 7.8–22.3) and the treatment (RR 17.2; 95% CI 9.5–31.4), having the opportunity to communicate with the child's physicians (RR 21.3; 95% CI 11.7–38.8), being satisfied with the physicians conversation style (RR 30.6; 95% CI 14.4–64.9), having the emotional needs met (RR 22.2; 95% CI 11.8–41.9), and being met with care by the child's physicians (RR 32.0; 95% CI 15.2–67.7). After multivariable model selection, the strongest predictor of trust at the time of the third chemotherapy cycle was to be met with care at the start of treatment.

Conclusion

Parents being met with care by the child's physicians at the beginning of the child's chemotherapy treatment develop an increased trust in the medical care. Copyright © 2012 John Wiley & Sons, Ltd.
Calibration and Uncertainty Analysis of an Optical Emission Spectrometer Measuring the Absolute Spectral Radiant Exitance of UV Signatures
Authors: Lee Hyungwoo , Oh Changhoon , Hahn Jae W.
Published: January 2012

An optical emission spectrometer (OES) was designed and constructed to detect the absolute spectral radiant exitance of UV signatures for a wavelength range of 240 nm to 440 nm. Using a directly heated graphite black body furnace operating at a temperature of 3000 K, the spectral response of the OES in the UV range was calibrated. To evaluate the performance of the OES system, the emission spectra of molecules were measured in a butane flame and the absolute emissions of the UV signatures were calculated. The uncertainty of the absolute measurement of the UV signature was analyzed by considering various uncertainty budgets, and the total uncertainty of the OES was found to be 1.66 %.
A residue in helical conformation in the native state adopts a β‐strand conformation in the folding transition state despite its high and canonical ϕ‐value
Authors: Zarrine‐Afsar Arash , Dahesh Samira , Davidson Alan R.
Published: January 2012

Delineating structures of the transition states in protein folding reactions has provided great insight into the mechanisms by which proteins fold. The most common method for obtaining this information is Φ‐value analysis, which is carried out by measuring the changes in the folding and unfolding rates caused by single amino acid substitutions at various positions within a given protein. Canonical Φ‐values range between 0 and 1, and residues displaying high values within this range are interpreted to be important in stabilizing the transition state structure, and to elicit this stabilization through native‐like interactions. Although very successful in defining the general features of transition state structures, Φ‐value analysis can be confounded when non‐native interactions stabilize this state. In addition, direct information on backbone conformation within the transition state is not provided. In the work described here, we have investigated structure formation at a conserved β‐bulge (with helical conformation) in the Fyn SH3 domain by characterizing the effects of substituting all natural amino acids at one position within this structural motif. By comparing the effects on folding rates of these substitutions with database‐derived local structure propensity values, we have determined that this position adopts a non‐native backbone conformation in the folding transition state. This result is surprising because this position displays a high and canonical Φ‐value of 0.7. This work emphasizes the potential role of non‐native conformations in folding pathways and demonstrates that even positions displaying high and canonical Φ‐values may, nevertheless, adopt a non‐native conformation in the transition state. Proteins 2012;. © 2012 Wiley Periodicals, Inc.
Effects of quinestrol and levonorgestrel on populations of plateau pikas, Ochotona curzoniae, in the Qinghai‐Tibetan Plateau
Authors: Liu Ming , Qu Jiapeng , Yang Min , Wang Zengli , Wang Yanling , Zhang Yanming , Zhang Zhibin
Published: January 2012

BACKGROUND: Plateau pikas (Ochotona curzoniae, Hodgson, 1858) are viewed as a pest in the Tibetan Plateau meadow ecosystem when their population densities are high. Traditional culling using rodenticides often poses a high risk to non‐target species and even to humans. In this study, an investigation was made of the infertility effects of quinestrol (E), levonorgestrel (P) and a combination of the two (EP, ratio E:P = 1:2) on plateau pikas during 2007 and 2008.

RESULTS: Treatment with E or EP significantly decreased the pregnancy rate of female pikas in 2007. In 2008, there was a cross‐year effect that still suppressed male reproduction in treated groups. Treatment with E obviously reduced the reproduction of pikas but not their population abundance in 2007; the reduction in population size was significant in 2008.

CONCLUSIONS: Single baiting of quinestrol in early breeding season reduced the reproduction and population size of pikas throughout 2007. The effect of infertility lasted into the next breeding season through a cross‐year effect, which resulted in a significant reduction of population size in 2008. Quinestrol is a very promising non‐lethal approach to managing pika populations; however, several factors need to be investigated further to improve the practicality of this method. Copyright © 2012 Society of Chemical Industry
Enhanced light output power of green LEDs employing AlGaN interlayer in InGaN/GaN MQW structure on sapphire (0001) substrate
Authors: Shioda Tomonari , Yoshida Hisashi , Tachibana Koichi , Sugiyama Naoharu , Nunoue Shinya
Published: January 2012

In order to enhance light output power of green light‐emitting diodes (LEDs) on a sapphire (0001) substrate, we employ 1.5 nm‐thick AlGaN interlayer between an InGaN well layer and an upper GaN barrier layer. AlGaN interlayer controls asymmetric band profile due to piezoelectric field, and thus it controls the quantum‐confined Stark effect. Although both photoluminescence intensity and electroluminescence intensity of a conventional MQW decreases drastically as the emission wavelength becomes longer, the intensity drop at spectral range of 530–580 nm is suppressed by utilizing an AlGaN interlayer. The maximum light output power of 12 mW at 532 nm and external quantum efficiency of 25.4% have been achieved for the LED employing Al0.30Ga0.70N interlayer at a driving current of 20 mA. This result indicates that the band‐engineering approach is effective for an IQE enhancement at pure green or longer wavelength, even if a polar (0001) face is utilized.
GaN‐based high‐frequency devices and circuits: A Fraunhofer perspective
Authors: Waltereit Patrick , Bronner Wolfgang , Quay Rüdiger , Dammann Michael , Cäsar Markus , Müller Stefan , van Raay Friedbert , Kiefer Rudolf , Brückner Peter , Kühn Jutta , Musser Markus , Kirste Lutz , Haupt Christian , Pletschen Wilfried , Lim Taek , Aidam Rolf , Mikulla Michael , Ambacher Oliver
Published: January 2012

We present the current status of our technology for GaN‐based HEMTs and MMICs as well as results ranging from the L‐band up to the W‐band. Epitaxial growth is carried out on 4H‐SiC(0001) substrates by both MOCVD and MBE. Processing is done using standard III–V equipment including both frontside and backside processing. For L‐band power bars we arrive at output powers, efficiencies and gains beyond 100 W, 60% and 17 dB, all measured under cw conditions at 50 V drain bias. The X‐band MMICs are characterized by a high efficiency above 40% for two‐stage amplifiers. Towards mm‐wave applications we have fabricated HEMTs with transit frequencies above 100 GHz and W‐band MMICs delivering 0.5 W/mm at 94 GHz with 7% PAE. First quaternary InAlGaN barriers show promising results for this new materials system. Reliability tests return a very good long‐term stability of our devices even at an elevated channel temperature of 200 °C with an extrapolated lifetime of 5 × 105. Initial space capability tests including total ion dose radiation insensitivity, radiation displacement damage, hydrogen poisoning and single event effect are successfully passed.
Large polycyclic aromatic hydrocarbons for application in donor–acceptor photovoltaics
Authors: Hesse Holger Christian , Schaffer Christoph , Hundschell Christian , Narita Akimitsu , Feng Xinliang , Müllen Klaus , Nickel Bert , Schmidt‐Mende Lukas
Published: January 2012

We present the photovoltaic application of a donor–acceptor system consisting of very large polycyclic aromatic hydrocarbons. Using vacuum sublimated hexa‐peri‐hexabenzocoronenes we evidence long exciton diffusion lengths of approximately 25 nm. In conjunction with the heaxfluorinated analogue for the first time a photovoltaic device using nanographene as active material for both donor and acceptor compounds was fabricated. The bi‐layered device exhibits a remarkably high open circuit voltage of 1.39 V. Light absorption of the photoactive materials used here is strictly confined to wavelengths below 500 nm, rendering this approach especially interesting for the application in semi‐transparent devices as well as multi‐layered and tandem solar cells.

magnified image

The photovoltaic performance of devices based on vacuum sublimated hexa‐peri‐hexabenzocoronenes is shown.
Dependence of magnetization on cation distributions in the spinel ferrites Cu1 − xZnxFe2O4(0.0 ≤ x ≤ 1.0)
Authors: Han Q. J. , Ji D. H. , Tang G. D. , Li Z. Z. , Hou X. , Qi W. H. , Bian R. R. , Liu S. R.
Published: January 2012

Ferrite samples of the composition Cu1 − xZnxFe2O4(0.0 ≤ x ≤ 1.0) were synthesized by chemical coprecipitation. The samples exhibited a single‐phase cubic spinel structure and the saturation magnetization of the samples was found to increase with increasing Zn content, whenx ≤ 0.4; and then decreased with increasingx. The dependence of magnetization on cation distributions in the ferrite samples has been estimated using a quantum‐mechanical method proposed by our group. Estimated cation distributions obtained by fitting the magnetic moments of the samples were used to perform Rietveld fitting for X‐ray diffraction patterns. The acceptable error parameters in the Rietveld fitting indicate that the estimated cation distributions in the samples are reasonable.
Dielectric function and bowing parameters of InGaN alloys
Authors: Sakalauskas E. , Tuna Ö. , Kraus A. , Bremers H. , Rossow U. , Giesen C. , Heuken M. , Hangleiter A. , Gobsch G. , Goldhahn R.
Published: January 2012

Ga‐rich (0001)‐oriented InxGa1−xN alloys grown by molecular beam epitaxy or metal‐organic vapour phase epitaxy on GaN/sapphire templates were investigated by spectroscopic ellipsometry at room temperature. The analysis of the extracted dielectric function yielded the characteristic transition energies, i.e., for the band gaps and the high‐energy critical points (van Hove singularities). Accounting for strain by using the k · p formalism, a band‐gap bowing parameter of 1.65 ± 0.07 eV for strain‐free material was deduced. It is consistent with the ab initio calculated band‐gap‐dependence for uniform (not clustered) InGaN alloys. The bowing parameters for the high‐energy inter‐band transitions were found to be close to ∼1 eV.
Carrier recombination processes in In‐polar and N‐polar p‐type InN films
Authors: Imai Daichi , Ishitani Yoshihiro , Fujiwara Masayuki , Wang Xinqian , Kusakabe Kazuhide , Yoshikawa Akihiko
Published: January 2012

Radiative recombination efficiency in InN is lower than the other III nitride binary compounds (GaN, AlN). Particularly, photoluminescence (PL) intensity in p‐InN is weaker than that in n‐InN by three orders or more. We investigate the nonradiative recombination (NR) processes in InN with respect to carrier density, activation energy of NR processes, and carrier scattering rate of the inside bulk region estimated by infrared (IR) measurements, and show that NR centers of p‐InN originate from the same defect species as those of n‐type films. We also compare PL properties of N‐polar and In‐polar samples, and show that NR process is initiated by electron capture by deep levels of accepter nature.
Low‐temperature photoluminescence studies of In‐rich InAlN nanocolumns
Authors: Kamimura Jumpei , Kishino Katsumi , Kikuchi Akihiko
Published: January 2012

High‐quality Inx Al1–xN (0.71 ≤ xIn ≤ 1.00) nanocolumns (NCs) have been grown on Si(111) substrates by rf‐plasma‐assisted molecular‐beam epitaxy (rf‐MBE). Low‐temperature photoluminescence (LT‐PL) spectra of various In‐rich InAlN NCs were measured at 4 K and single peak PL emissions were observed in the wavelength region from 0.89 µm to 1.79 µm. Temperature‐dependent PL spectra of In0.92Al0.08N NCs were studied and the so‐called “S‐shape” (decrease–increase–decrease) PL peak energy shift was observed with increasing temperature. This shift indicates the carrier localization induced by the In segregation effect and is different from the anomalous blue shift frequently observed in InN films and nanowires with high residual carrier concentra‐ tions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Highly Size‐ and Shape‐Controlled Synthesis of Silver Nanoparticles via a Templated Tollens Reaction
Authors: Dondi Ruggero , Su Wu , Griffith Gerry A. , Clark Graham , Burley Glenn A.
Published: January 2012

A mild, facile one‐step synthetic strategy for the preparation of size‐ and shape‐controlled silver nanoparticles (AgNPs) is presented. The high degree of size‐ and shape‐control of these AgNPs is achieved by the use of triazole sugar ligands scaffolded by a central resorcinol ether core. Both the triazoles and the resorcinol ether core mediate the nucleation, growth, and passivation phases of the preparation of AgNP in the presence of the Tollens reagent as the silver source. Kinetic and 1H NMR titration data is presented describing the nature of the interactions between the Tollens reagent and these ligands.
Predictive Gold Nanocluster Formation Controlled by Metal‐Ligand Complexes
Authors: Pettibone John M. , Hudgens Jeffrey W.
Published: January 2012

The formation of ligand‐protected gold nanoclusters during size‐selective syntheses is seemingly driven by the inherent properties of the protecting ligands, but a general description of the product formation has not been presented. This study uses diphosphine‐protected Au clusters as a model system to examine i) control of metal‐ligand complex distributions in methanol–chloroform solutions, ii) role of solution perturbations, e.g., oxidation, and iii) nanocluster formation through reduction of characterized complex distributions. By selectively reducing complexes and monitoring cluster formation with electrospray ionization mass spectrometry and UV–vis, data show the distribution of complexes can be controlled through ligand exchange, and the reduction of specific complexes produce characteristic ligated gold clusters based on ligand class. Specifically, 1,n‐bis(diphenylphosphino)n‐alkane ligands, Ln, where n = 1 through 6, are classified into two distinct sets. The classes represent ligands that either form mainly [AuLn2]+ (Class I, n = 1–3) or bridged [Au2Ln2]2+ (Class II, n = 4–6) complexes after complete ligand exchange with AuClPPh3. Selectively reducing gold‐phosphine ligand complexes allows mapping of product formation, resulting collectively in a predictive tool for ligated gold cluster production by simply monitoring the initial complex distribution prior to reduction.
Genome-Wide Analysis of N1ICD/RBPJ Targets In Vivo Reveals Direct Transcriptional Regulation of Wnt, SHH, and Hippo Pathway Effectors by Notch1
Authors: Li Yaochen , Hibbs Matthew Aaron , Gard Ashley Lauren , Shylo Natalia Aliakseeuna , Yun Kyuson
Published: January 2012

The Notch pathway plays a pivotal role in regulating cell fate decisions in many stem cell systems. However, the full repertoire of Notch target genes in vivo and the mechanisms through which this pathway activity is integrated with other signaling pathways are largely unknown. Here, we report a transgenic mouse in which the activation of the Notch pathway massively expands the neural stem cell (NSC) pool in a cell context-dependent manner. Using this in vivo system, we identify direct targets of RBPJ/N1ICD in cortical NSCs at a genome-wide level through combined ChIP-Seq and transcriptome analyses. Through a highly conservative analysis of these datasets, we identified 98 genes that are directly regulated by N1ICD/RPBJ in vivo. These include many transcription factors that are known to be critical for NSC self-renewal (Sox2, Pax6, Tlx, and Id4) and the transcriptional effectors of the Wnt, SHH, and Hippo pathways, TCF4, Gli2, Gli3, Yap1, and Tead2. Since little is known about the function of the Hippo-Yap pathway in NSCs, we analyzed Yap1 expression and function in NSCs. We show that Yap1 expression is restricted to the stem cell compartment in the developing forebrain and that its expression is sufficient to rescue Notch pathway inhibition in NSC self-renewal assays. Together, results of this study reveal a previously underappreciated complexity and breadth of Notch1 targets in vivo and show direct interaction between Notch and Hippo-Yap pathways in NSCs.

Disclosure of potential conflicts of interest is found at the end of this article.
Structural Synthon Approach to the Study of Stacking Faults in the Layered Double Hydroxides of Lithium and Aluminum
Authors: Britto Sylvia , Kamath P. Vishnu
Published: January 2012

A single layer of the Li‐Al layered double hydroxide (LDH) can be considered to be a structural synthon that can be stacked in a number of ways to give rise to the polytypes of the Li‐Al LDH family. The topotactic imbibition of lithium into gibbsite and bayerite precursors gives rise to crystalline 2H and 1M1 polytypes respectively. In contrast the sample formed through a gel to crystallite route is found to be a 1M1 polytype with stacking disorders whose local symmetry corresponds to the 1M2 polytype. On heating, a solid‐solid 1M1→1H polytype transformation is observed.
Synthese von verbrückend substituierten sekundären Phosphanen sowie deren Reaktionen mit Triisopropylindium
Authors: von Hänisch Carsten , Kracke Andreas
Published: January 2012

In this work we report the synthesis and characterisation of the 1.5‐diphosphanyldiethylether O{C2H4PH(SiiPr3)}2 (2) in which two silyl‐substituted phosphine groups are linked by an ether bridge as well as the compound O(SiiPr2PHEt)2 (3) where two ethyl substitute phosphine groups are connected by a siloxane bridge. In addition, we describe the metalation of 2 and 3 with triisopropylindium. These reactions lead to the compounds [O{C2H4P(SiiPr3)IniPr2}2] (4) and [O{SiiPr2P(Et)IniPr2}2] (5) with In2P2 ring structures.
Four LnIII‐MgII Metal Organic Frameworks Containing Fan‐like Helices and Independent [Mg(H2O)6]2+ Units
Authors: Chang Li‐Mei , Zhao Xia , Gu Zhi‐Gang , Liu Wen‐Jing , Wei Zhi‐Qiang , Liu Ying‐Liang , Mo Hai‐Hong , Yue Shan‐Tang
Published: January 2012

Four LnII‐MgII metal organic frameworks, namely {Mg(H2O)6·[MgLn(oda)3]2}·6H2O [Ln = Eu (1), Tb (2), Gd (3), Nd (4); H2oda = 2, 2′‐oxydiacetic acid], were synthesized by self‐assembly reactions under hydrothermal conditions and characterized by single‐crystal X‐ray crystal diffraction, elemental analysis, IR spectroscopy as well as thermal analysis. Single‐crystal analysis shows that all four compounds are isostructural and exhibit three‐dimensional metal organic frameworks constructed by fan‐like helices and isolated [Mg(H2O)6]2+ units. Meanwhile, the solid‐state luminescence properties of compounds 1 and 2 were also investigated.
Hydroxylammonium 5‐Nitriminotetrazolates
Authors: Fischer Niko , Klapötke Thomas M. , Piercey Davin G. , Stierstorfer Jörg
Published: January 2012

The hydroxylammonium salts of monodeprotonated 5‐nitriminotetrazole (4), double deprotonated 5‐nitriminotetrazole (5), 1‐methyl‐5‐nitriminotetrazole (6), and 2‐methyl‐5‐nitraminotetrazole (7) have been prepared in high yield from the corresponding 5‐nitriminotetrazoles as free acids and an aqueous solution of hydroxylamine or the metathesis reactions of hydroxylammonium hydrochloride with the silver salt of the corresponding nitriminotetrazole, respectively. The energetic salts 4–7 were fully characterized by single‐crystal X‐ray diffraction (4–6), NMR spectroscopy, IR‐ and Raman spectroscopy as well as DSC measurements. The sensitivities towards impact, friction and electrical discharge were determined. In addition, several detonation parameters (e.g. heat of explosion, detonation velocity) were computed by the EXPLO5.04 computer code based on calculated (CBS‐4M) heats of formation and X‐ray densities.
On the Rare Earth Metal Bismuthide Oxides RE2BiO2 (RE = Nd, Tb, Dy, Ho)
Authors: Nuss Jürgen , Jansen Martin
Published: January 2012

A series of new RE2BiO2 compounds (RE = Nd, Tb, Dy, Ho) has been synthesized from elemental bismuth, REBi, and RE2O3 in all‐solid state reactions in sealed tantalum ampoules at 1770 K. The dark grey metallic compounds adopt the anti‐ThCr2Si2 type of structure (I4/mmm, tI10), according to X‐ray single crystal structure analysis. As a main structural feature, there are PbO analogous slabs, [REO]+, and 44 nets of Bi2– anions, alternately stacked along the c‐axis.
Yeast culture collections of the world: meeting the needs of industrial researchers
Authors: Boundy-Mills Kyria
Published: January 2012

The importance of selecting optimal yeast strains for research or industrial applications is often underestimated. For example, utilizing a strain background that already provides the desired stress tolerance or nutrient utilization profile can eliminate costly strain optimization. Yeast culture collections can provide not only the yeast strains but also data and curator expertise to help narrow the search for the optimal strain. While some collections are known for a broad range of cultures and services, other “boutique” collections can provide a broader selection of strains of certain categories, a surprising amount of characterization data, and assistance in selecting strains. This article provides information on dozens of yeast collections of the world, profiles of selected yeast culture collections, and the services that they provide: e.g., strain preservation for patent or safe deposit purposes, species identification service, training workshops, and consulting on yeast identification and physiology. Utilization of these services can save industrial researchers valuable time and resources.
Update on clinical aspects and treatment of selected vitamin‐responsive disorders II (riboflavin and CoQ10)
Authors: Horvath Rita
Published: January 2012

Riboflavin and ubiquinone (Coenzyme Q10, CoQ10) deficiencies are heterogeneous groups of autosomal recessive conditions affecting both children and adults. Riboflavin (vitamin B2)‐derived cofactors are essential for the function of numerous dehydrogenases. Genetic defects of the riboflavin transport have been detected in Brown‐Vialetto‐Van Laere and Fazio‐Londe syndromes (C20orf54), and haploinsufficiency of GPR172B has been proposed in one patient to cause persistent riboflavin deficiency. Mutations in the electron tranferring fravoprotein genes (ETFA/ETFB) and its dehydrogenase (ETFDH) are causative for multiple acyl‐CoA dehydrogenase deficiency. Mutations in ACAD9, encoding the acyl‐CoA dehydrogenase 9 protein were recently reported in mitochondrial disease with respiratory chain complex I deficiency. All these conditions may respond to riboflavin therapy. CoQ10 is a lipid‐soluble component of the cell membranes, where it functions as a mobile electron and proton carrier, but also participates in other cellular processes as a potent antioxidant, and by influencing pyrimidine metabolism. The increasing number of molecular defects in enzymes of the CoQ10 biosynthetic pathways (PDSS1, PDSS2, COQ2, COQ6, COQ9, CABC1/ADCK3) underlies the importance of these conditions. The clinical heterogeneity may reflect blocks at different levels in the complex biosynthetic pathway. Despite the identification of several primary CoQ10 deficiency genes, the number of reported patients is still low, and no true genotype‐phenotype correlations are known which makes the genetic diagnosis still difficult. Additionally to primary CoQ10 deficiencies, where the mutation impairs a protein directly involved in CoQ10 biosynthesis, we can differentiate secondary deficiencies. CoQ10 supplementation may be beneficial in both primary and secondary deficiencies and therefore the early recognition of these diseases is of utmost importance.
Heterozygosity for an in‐frame deletion causes glutaryl‐CoA dehydrogenase deficiency in a patient detected by newborn screening: investigation of the effect of the mutant allele
Authors: Bross Peter , Frederiksen Jane B. , Bie Anne S. , Hansen Jakob , Palmfeldt Johan , Nielsen Marit N. , Duno Morten , Lund Allan M. , Christensen Ernst
Published: January 2012

A patient with suspected glutaric aciduria type 1 (GA‐1) was detected by newborn screening. GA‐1 is known as an autosomal recessively inherited disease due to defects in the gene coding for glutaryl‐CoA dehydrogenase (GCDH), a mitochondrial enzyme involved in the catabolism of the amino acids hydroxylysine, lysine and tryptophan. DNA and cDNA sequencing revealed a 18 bp deletion (c.553_570del18) resulting in deletion of six amino acids (p.Gly185_Ser190del) in one allele and no sequence changes in the other allele. Confirmatory biochemical analysis of blood, urine and cultured fibroblasts from the proband were consistent with a mild biochemical GA‐1 phenotype. Recombinant expression of the mutant variant in E. coli showed that the GCDH‐(p.Gly185_Ser190del) protein displayed severely decreased assembly into tetramers and enzyme activity. To discover a potential dominant negative effect of the mutant protein, we engineered a prokaryotic expression system in which expression of a wild type and a mutant GCDH allele is controlled by separately inducible promoters. These cells displayed decreased levels of GCDH tetramer and enzyme activity when expressing both the wild type and the mutant GCDH variant protein compared to the situation when only the wild type allele was expressed. Further experiments suggest that the major impact of the GCDH‐(p.Gly185_Ser190del) protein in heterozygous cells consists of hampering the assembly of wild type GCDH into tetramers. Our experimental data are consistent with the hypothesis that heterozygosity for this mutation confers a dominant negative effect resulting in a GCDH enzyme activity that is significantly lower than the expected 50%.
Endothelial function in children and adolescents with mucopolysaccharidosis
Authors: Kelly Aaron S. , Metzig Andrea M. , Steinberger Julia , Braunlin Elizabeth A.
Published: January 2012

Background

Although coronary artery pathology is a prominent feature of mucopolysaccharidosis (MPS), it may be underestimated by coronary angiography because of its diffuse nature. It is also generally assumed that cardiovascular risk is increased in MPS and reduced following hematopoietic stem cell transplantation (HSCT) or enzyme replacement therapy (ERT), but this has never been formally evaluated. Non‐invasive methods of assessing vascular endothelial function may provide a measure of cardiovascular risk in MPS. We evaluated endothelial function, using digital reactive hyperemia, in youth with MPS and in healthy controls.

Methods

Digital reactive hyperemic index (RHI) was measured in 12 children and adolescents (age 10.3 ± 3.9 years old; 11 boys) with treated MPS and nine age‐ and gender‐matched (11.4 ± 4.0; 8 boys) healthy controls. An independent t‐test was used to compare RHI between individuals with MPS and controls.

Results

Children and adolescents with MPS (MPS type II: N = 5; type I: N = 4; type VI: N = 3) whether treated by HSCT (N = 4) or ERT (N = 8) had significantly lower RHI compared to controls (MPS 1.22 ± 0.19 vs. controls 1.46 ± 0.32, p < 0.05).

Conclusion

These preliminary findings suggest that children and adolescents with treated MPS have significantly poorer endothelial function when compared to healthy controls. Further investigation into the utility of endothelial function for risk stratification and the long term implications of reduced endothelial function in MPS is warranted.
Recognition of different DNA sequences by a DNA‐binding protein alters protein dynamics differentially
Authors: Mondol Tanumoy , Batabyal Subrata , Mazumder Abhishek , Roy Siddhartha , Pal Samir Kumar
Published: January 2012

λ‐Repressor–operator sites interaction, particularly OR1 and OR2, is a key component of the λ‐genetic switch. FRET from the dansyl bound to the C‐terminal domain of the protein, to the intercalated EtBr in the operator DNA indicates that the structure of the protein is more compact in the OR2 complex than in the OR1 complex. Fluorescence anisotropy reveals enhanced flexibility of the C‐terminal domain of the repressor at fast timescales after complex formation with OR1. In contrast, OR2 bound repressor shows no significant enhancement of protein dynamics at these timescales. These differences are shown to be important for correct protein–protein interactions. Altered protein dynamics upon specific DNA sequence recognition may play important roles in assembly of regulatory proteins at the correct positions.
Reduction of serotonergic neurons in the dorsal raphe due to chronic prenatal administration of a tryptophan‐free diet
Authors: Flores‐Cruz Guadalupe M. , Escobar Alfonso
Published: January 2012

Serotonin (5‐HT) is a widely studied neurotransmitter which plays an important role in the development and proper functioning of the organism throughout life. The appearance of 5‐HT system early in ontogeny suggests the hypothesis that 5‐HT plays a regulatory role in neurodevelopment. This study investigated the effect of administration of a tryptophan deficient diet during prenatal development on the morphology and cell population of the dorsal raphe. The experimental diet, containing balanced amounts of carbohydrates, lipids and proteins, was provided to a time‐mated group of rats from gestational day 5 until delivery. Control groups were fed with (i) the experimental diet formulation with 0.2% tryptophan added to the mixture, or (ii) a regular chow diet. At delivery, five pups per dam were euthanized. Body and brain weight was measured and brain sections were processed for immunohistochemistry for tryptophan hydroxylase (TrpH) and whole brain 5‐HT analysis. Sections containing dorsal raphe were photographed with a light microscope and TrpH positive neurons quantified. Brain weights in the tryptophan deprived group showed no difference as compared with controls while body weights were reduced by 25%. Total numbers of serotonergic neurons at the dorsal raphe in the prenatal tryptophan deficient pups were reduced by 35%. A regional analysis of the dorsal raphe indicated a marked cellular reduction in the medial and caudal sections of the nucleus, which contains the majority of serotonergic neurons, in the tryptophan deprived condition. Quantitative 5‐HT analysis showed that the brain concentration was similar among conditions. In conclusion, gestational tryptophan deprivation exerts adverse effects on the development of the 5‐HT system, particularly in the dorsal raphe, manifested by decreased numbers of serotonergic neurons as well as altered topography in this important nucleus.
New concepts of science and medicine in science and technology studies and their relevance to science education
Authors: Wang Hsiu‐Yun , Stocker Joel F. , Fu Daiwie
Published: January 2012

Science education often adopts a narrow view of science that assumes the lay public is ignorant, which seemingly justifies a science education limited to a promotional narrative of progress in the form of scientific knowledge void of meaningful social context. We propose that to prepare students as future concerned citizens of a technoscientific society, science education should be informed by science, technology, and society (STS) perspectives. An STS‐informed science education, in our view, will include the following curricular elements: science controversy education, gender issues, historical perspective, and a move away from a Eurocentric view by looking into the distinctive patterns of other regional (in this case of Taiwan, East Asian) approaches to science, technology, and medicine. This article outlines the significance of some major STS studies as a means of illustrating the ways in which STS perspectives can, if incorporated into science education, enhance our understanding of science and technology and their relationships with society.
Transition from hydrodynamic turbulence to magnetohydrodynamic turbulence in von Kármán flows
Authors: Verhille Gautier , Khalilov Ruslan , Plihon Nicolas , Frick Peter , Pinton Jean-François
Published: January 2012

The influence of an externally applied magnetic field on flow turbulence is investigated in liquid-gallium von-Kármán (VK) swirling flows. Time-resolved measurements of global variables (such as the flow power consumption) and local recordings of the induced magnetic field are made. From these measurements, an effective Reynolds number is introduced as ${\mathit{Rm}}_{\mathit{eff}} = \mathit{Rm}(1\ensuremath{-} \ensuremath{\alpha} \sqrt{N} )$, so as to take into account the influence of the interaction parameter $N$. This effective magnetic Reynolds number leads to unified scalings for both global variables and the locally induced magnetic field. In addition, when the flow rotation axis is perpendicular to the direction of the applied magnetic field, significant flow and induced magnetic field fluctuations are observed at low interaction parameter values, but corresponding to an Alfvèn speed ${v}_{A} $ of the order of the fluid velocity fluctuations ${u}_{\mathit{rms}} $. This strong increase in the flow fluctuations is attributed to chaotic changes between hydrodynamic and magnetohydrodynamic velocity profiles.
The Discovery of Engravings upon Flint Crust at Grime's Graves, Norfolk
Authors: Armstrong A. Leslie
Published: January 2012

Excavations at Grime's Graves, Norfolk, during September 1920, revealed a new chipping site (Floor 85), and resulted in the discovery thereon of two pieces of engraved flint crust, associated with a series of flint implements of Le Moustier type, bone tools, and pottery, upon a living level immediately overlying glacial sand.
Discoveries at Amesbury
Authors: Weaver Lawrence
Published: January 2012

On 26th June 1920 workmen in the employ of the Ministry of Agriculture and Fisheries, whilst excavating at the Ministry's Farm Settlement at Amesbury, discovered some bones of a skeleton. The site lies approximately 175 yards north-east of Ratfyn Barrow (marked on the Ordnance Map), and about 6 in. below the surface of the chalk. The grave was about 7 ft. long and about 2 ft. 3 in. in depth. Mr. P. Farrar, of Bulford Camp, a local archaeologist, was at once communicated with, and discovered further remains after a careful search.
Museums in the Present and Future
Authors: Read Hercules
Published: January 2012

The intelligent world has of late been passing through one of its cyclical phases. It would hardly be suspected that in these times the daily tale of news from home and abroad should be so wanting in human interest that it was necessary to seek for recondite subjects. Nevertheless astute editors or others on the staff of our daily newspapers have been constrained to discover that all is not well in our artistic atmosphere, and they call attention to the sad need of refinement in our surroundings, that our street architecture, though showing signs of grace, lacks coherence and taste, that our statues are deplorable, our public monuments wanting in dignity or design, and that, in fine, the necessity for organization and method is called for as much for our spiritual betterment as it is on the material side. A number of distinguished men, architects, painters, and critics of both, and of all else, have come forward, and their plans for a new and glorified earth have been placed before a grateful world.