bluuebunny/crossref_metadata_2025 huggingface dataset:
Domain distribution and intrinsic disorder in hubs in the human protein–protein interaction network
Authors: Patil Ashwini , Kinoshita Kengo , Nakamura Haruki
Published: May 2010

Intrinsic disorder and distributed surface charge have been previously identified as some of the characteristics that differentiate hubs (proteins with a large number of interactions) from non‐hubs in protein–protein interaction networks. In this study, we investigated the differences in the quantity, diversity, and functional nature of Pfam domains, and their relationship with intrinsic disorder, in hubs and non‐hubs. We found that proteins with a more diverse domain composition were over‐represented in hubs when compared with non‐hubs, with the number of interactions in hubs increasing with domain diversity. Conversely, the fraction of intrinsic disorder in hubs decreased with increasing number of ordered domains. The difference in the levels of disorder was more prominent in hubs and non‐hubs with fewer domains. Functional analysis showed that hubs were enriched in kinase and adaptor domains acting primarily in signal transduction and transcription regulation, whereas non‐hubs had more DNA‐binding domains and were involved in catalytic activity. Consistent with the differences in the functional nature of their domains, hubs with two or more domains were more likely to connect distinct functional modules in the interaction network when compared with single domain hubs. We conclude that the availability of greater number and diversity of ordered domains, in addition to the tendency to have promiscuous domains, differentiates hubs from non‐hubs and provides an additional means of achieving interaction promiscuity. Further, hubs with fewer domains use greater levels of intrinsic disorder to facilitate interaction promiscuity with the prevalence of disorder decreasing with increasing number of ordered domains.
Apoptosis regulators Fau and Bcl‐G are down‐regulated in prostate cancer
Authors: Pickard Mark R. , Edwards Sandra E. , Cooper Colin S. , Williams Gwyn T.
Published: May 2010

BACKGROUND

The molecular control of cell death through apoptosis is compromised in prostate cancer cells, resulting in inappropriate cell survival and resistance to cytotoxic therapy. Reduced expression of the functionally connected apoptosis‐regulators and candidate tumor suppressors Fau and Bcl‐G has recently been implicated in oncogenesis in other tissues. The present study examines the hypothesis that reduced expression of these genes may be involved in prostate cancer.

METHODS

Fau and Bcl‐G mRNA levels were determined by real time RT‐PCR in two independent prostate tissue collections. In experiments in vitro, Fau and Bcl‐G levels in prostate cancer cell lines were reduced using RNA interference and the effects on sensitivity to UVC irradiation were determined.

RESULTS

Fau and Bcl‐G mRNA levels were both lower in prostate cancer tissue than in normal prostate and Benign Prostate Hyperplasia. Active down‐regulation of Fau and Bcl‐G expression in vitro resulted in decreased sensitivity to UVC‐induced cytotoxicity. Simultaneous down‐regulation of Fau and Bcl‐G produced a decrease in sensitivity which was similar to either gene alone.

CONCLUSIONS

Fau and Bcl‐G mRNA levels are both decreased in prostate cancer. In prostate cancer cell lines in vitro such down‐regulation results in reduced sensitivity to UVC‐induced cytotoxicity, consistent with the putative roles of these genes as candidate prostate tumor suppressors. The absence of an additive effect when Fau and Bcl‐G were down‐regulated simultaneously is consistent with the two genes acting in the same apoptosis pathway, for example, with the pro‐apoptotic effects of Fau being mediated through modulation of Bcl‐G. Prostate 70: 1513–1523, 2010. © 2010 Wiley‐Liss, Inc.
Comparing the folding free‐energy landscapes of Aβ42 variants with different aggregation properties
Authors: Mitternacht Simon , Staneva Iskra , Härd Torleif , Irbäck Anders
Published: May 2010

The properties of the amyloid‐β peptide that lead to aggregation associated with Alzheimer's disease are not fully understood. This study aims at identifying conformational differences among four variants of full‐length Aβ42 that are known to display very different aggregation properties. By extensive all‐atom Monte Carlo simulations, we find that a variety of β‐sheet structures with distinct turns are readily accessible for full‐length Aβ42. In the simulations, wild type (WT) Aβ42 preferentially populates two major classes of conformations, either extended with high β‐sheet content or more compact with lower β‐sheet content. The three mutations studied alter the balance between these classes. Strong mutational effects are observed in a region centered at residues 23–26, where WT Aβ42 tends to form a turn. The aggregation‐accelerating E22G mutation associated with early onset of Alzheimer's disease makes this turn region conformationally more diverse, whereas the aggregation‐decelerating F20E mutation has the reverse effect, and the E22G/I31E mutation reduces the turn population. Comparing results for the four Aβ42 variants, we identify specific conformational properties of residues 23–26 that might play a key role in aggregation. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Interaction of the prion protein fragment PrP 185–206 with biological membranes: effect on membrane permeability
Authors: Sonkina Sabina , Tukhfatullina Ilnor I. , Benseny‐Cases Núria , Ionov Maksim , Bryszewska Maria , Salakhutdinov Bakhtiyar A. , Cladera Josep
Published: May 2010

Amyloids are proteinaceous aggregates related to the so‐called conformational diseases, such as Alzheimer's and prion diseases. The cytotoxicity of amyloids may be related to the interaction of the amiloidogenic peptides or proteins with the cell membrane. In order to gain information on the physico‐chemical effects of amyloids on membranes, we have studied the interaction of the human prion amyloidogenic fragment PrP 185–206 with negatively charged model membranes. The results show that the peptide causes the destabilization of the membrane, making it permeable to potassium ions and to charged organic compounds. This effect correlates with the interaction of the peptide with the membrane, causing a variation in the magnitude of the electrostatic surface and dipole membrane potentials. This effect on the electrostatic properties of the membranes may help explaining the observed permeability: a neutralization of the surface negative charge and a decrease of the inside‐positive dipole potential would facilitate the translocation of positive ions. The structural analysis of the peptide in the presence of model membranes reveals that it adopts a predominantly unordered structure without any signs of amyloid formation. The results may be relevant in relation to the recently described cell toxic capacity of the peptide. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Total synthesis and stereochemical reassignment of tasiamide B
Authors: Sun Tiantian , Zhang Wei , Zong Chengli , Wang Peng , Li Yingxia
Published: May 2010

The first total synthesis of tasiamide B, an octapeptide bearing 4‐amino‐3‐hydroxy‐5‐phenylpentanoic acid unit isolated from the marine cyanobacteria Symploca sp. is described. A simple and efficient way was found to avoid the pyroglutamylation of Nα‐Me‐Gln and led to a reassignment of the Nα‐Me‐L‐Phe of tasiamide B to be Nα‐Me‐D‐Phe, which was also supported by 1D and 2D NMR. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Degradation mechanism of light‐emitting diodes on patterned sapphire substrate
Authors: Kim Sei‐Min , Moon Young‐Boo , Park Il‐Kyu , Jang Ja‐Soon
Published: May 2010

We have investigated possible degradation mechanism for patterned sapphire substrate (PSS)‐based blue light‐emitting diodes (LEDs) using an acceleration burn‐in test under high current stress. Normal LEDs without a PSS had also been compared. Measurements showed that the PSS‐LED has lower series resistance and higher output power compare to those of the normal LED. The acceleration test (@ 490 mA/cm2) results showed that the normal LED suffers from current crowding irrespective of acceleration time while the PSS LED endures up to 100 s. In addition, the estimated lifetime of the PSS‐LED is 1.6 times as high as that of the normal LED at high electrical stress of 490 A/cm2, indicating that the PSS‐LED shows excellent reliability characteristics. Based on electrical/optical measurement results, acceleration test data, and Auger depth profile results, possible degradation mechanism of the PSS‐LED will be discussed in terms of junction temperature (originating from Joule heating), carrier crowding, and p‐contact failure.
Structural characterization of thick (1122) GaN layers grown by HVPE on m‐plane sapphire
Authors: Usikov Alexander , Soukhoveev Vitali , Shapovalov Lisa , Syrkin Alexander , Ivantsov Vladimir , Scanlan Bernard , Nikiforov Alexey , Strittmatter Andre , Johnson Noble , Zheng Jian‐Guo , Spiberg Philippe , El‐Ghoroury Hussein
Published: May 2010

This paper reports structural characterization of thick $(11\bar {2}2)$‐oriented GaN layers by means of XRD, TEM, and micro‐ CL. The semi‐polar $(11\bar {2}2)$ GaN layers were grown on m‐plane sapphire substrates by HVPE. Their structural quality improved with thickness. Threading dislocation density of 3 × 108 cm−2 and stacking faults density of 4 × 104 cm−1 were measured at the surface of 20 µm thick $(11\bar {2}2)$ GaN layers. The semi‐polar GaN layers were used as template substrates to grow InGaN/GaN MQW heterostructures by MOCVD that demonstrated optically pumped lasing at 500 nm wavelength. The results demonstrate the longest wavelength yet reported for a photo‐pumped laser on template substrates.
Growth and characterization of GaN grown on moth‐eye patterned sapphire substrates
Authors: Ishihara Akihiro , Kawai Ryousuke , Kitano Thukasa , Suzuki Atushi , Kondo Toshiyuki , Iwaya Motoaki , Amano Hiroshi , Kamiyama Satoshi , Akasaki Isamu
Published: May 2010

To realize high‐efficiency light‐emitting diodes (LEDs), it is necessary to increase light extraction efficiency. Therefore, the introduction of a moth‐eye structure, which consists of periodic cones with a pitch of optical wavelength magnitude, into a sapphire surface before the epitaxial growth of nitride films is very promising for reducing the reflectivity of light resulting in high light extraction efficiency. 450 nm GaInN/GaN LEDs were fabricated on conventional and moth‐eye substrates by metal organic vapor phase epitaxy (MOVPE). The intensety of room‐temperature photoluminescence emitted from the LED with the moth‐eye‐patterned sapphire substrate was 1.6 times higher than that emitted from the LED without the moth‐eye substrate. Under a current injection of 50 mA, the output power of the moth‐eye LED is 3.6 times higher than that of the conventional LED. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of pulsed injection of precursors in AlN‐MOVPE growth by computational fluid simulation
Authors: Nakamura Kenichi , Hirako Akira , Ohkawa Kazuhiro
Published: May 2010

We report computational analysis of gas‐phase states and main reaction pathways under AlN metalorganic vapor‐phase epitaxy (MOVPE) by pulsed injection (PI) method of precursors. Interval times of 0–2 s were inserted between trimethylaluminum (Al(CH3); TMAl) and ammonia (NH3) supply phases to suppress parasitic reactions. In the cases of the interval time of 0 s, polymers and Al‐N molecules were dominant species due to parasitic reaction, and the growth species was Al‐N molecules generated by TMAl:NH3 pyrolysis. When an interval time was inserted between TMAl and NH3, mixing of TMAl and NH3 were suppressed. Al and NH2 generated from each precursor were dominant species. The main reaction pathway changed from TMAl:NH3 pyrolysis into TMAl pyrolysis with increasing the interval time. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High drive current and high frequency response of GaN nanowire metal‐oxide‐semiconductor field‐effect transistor
Authors: Yu Jeng‐Wei , Wu Han‐Min , Peng Lung‐Han
Published: May 2010

We report the techniques of lateral epitaxial growth of horizontally aligned [11$ \bar 2 $0] GaN NWs and the photo‐enhanced chemical (PEC) oxidation process to enable the registration of crystalline gallium oxide (Ga2O3)/GaN NWs onto their growth sites over the SiO2/p‐Si substrates. This method allows the implementation of top‐gate Ga2O3/GaN NW‐metal oxide semiconductor field effect transistor (MOSFET) using the conventional optical lithography and the metal lift‐off procedures. This scheme enables photolithographic fabrication of top‐gate Ga2O3/GaN NW‐MOSFET of 60 nm dia. and 2 μm gate length. Device parameters with gm of 40 μS, saturation current of 90 μA, and cut‐off frequency fT at 22 GHz have been extracted (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design and performance of 1.55 μm laser using InGaN
Authors: Hasan Md. Tanvir , Islam Md. Jahirul , Hasan Rajib‐ul‐ , Islam Md. Sherajul , Yeasmin Shahrina , Bhuiyan Ashraful G. , Islam Md Rafiqul , Yamamoto Akio
Published: May 2010

This paper describes the theoretical design and performance of a novel InGaN‐based 1.55 μm quantum well laser. A careful analysis of the optical and modal gain, threshold behavior, optical output, and efficiency with cavity length has been carried out. The spectral range of the optical material gain is found to be narrow and modal gain varies sharply with changing the reflectivity of the partially transparent mirror. It is found that a very small voltage of 1.10 V is required to reach the threshold current. A very small threshold current of 5.1 mA is required to emit the light. The calculated values of threshold current and threshold voltage are lower than the reported values of the conventional 1.55 μm laser. An efficiency of around 59% is found for a cavity length of 300 μm keeping the reflectivity at 35% of one mirror and 100% of other. The above study indicates that the proposed InGaN‐based 1.55 μm laser is very promising for the fabrication of future high performance laser (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Threshold voltage control using SiNx in normally off AlGaN/GaN HFET with p‐GaN gate
Authors: Sugiyama T. , Iida D. , Iwaya M. , Kamiyama S. , Amano H. , Akasaki I.
Published: May 2010

The threshold voltage (Vth) of normally off‐mode AlGaN/GaN junction heterostructure field‐effect transistors with a p‐type GaN gate can be successfully controlled by inserting a SiNx insulator between the p‐GaN and a Ni/Au electrode. The Vth can be controlled from +1 V to above +8 V. Moreover, the gate leakage current of transistors decreases and their gate voltage at which gate current steeply increases becomes higher. The mechanism of the threshold voltage change is analyzed by the equivalent circuit model. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valence band structure of III‐V nitride films characterized by hard X‐ray photoelectron spectroscopy
Authors: Sumiya M. , Lozach M. , Matsuki N. , Ito S. , Ohhashi N. , Sakoda K. , Yoshikawa H. , Ueda S. , Kobayashi K.
Published: May 2010

The valence band structure and core level of non‐doped GaN and Mg‐ (7x1018cm–3), Si‐ (6x1017cm–3) doped GaN films grown by metalorganic chemical vapor deposition were investigated by hard x‐ray photoelectron spectroscopy (HX‐PES). The surface Fermi level of non‐doped GaN film was pinned near midgap at 1.8 eV from the valence band maximum (VBM). From the angular dependence of HX‐PES, upward and downward surface band bending was observed for GaN:Mg and GaN:Si, while the surface Fermi level was located at 1.3 eV and 1.9 eV from the VBM, respectively. Following the built‐in potential evaluated from 1/C2‐V of the Schottky contact, the bulk Fermi of GaN:Si film was estimated to be 3.1 eV (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic properties of nonpolar cubic GaN MOS structures
Authors: As D. J. , Pöttgen H. , Tschumak E. , Lischka K.
Published: May 2010

The electric characteristics of non‐polar cubic gallium nitride (GaN) metal‐oxide‐semiconductor (MOS) capacitors were measured by capacitance (C‐V) and conductance (Gp/ω–F) techniques. From the hysteresis in the C‐V curve and the peak height of the Gp/ω – frequency curves a maximum interface state density Dit of ∼2x1013cm–2eV–1 is estimated. An interface trap band existing about 0.3 eV below the conduction band is measured in non‐polar cubic gallium nitride (GaN). (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The temperature dependence of the band edge energy in calcium barium niobate
Authors: Heine Urs , Betzler Klaus , Burianek Manfred , Mühlberg Manfred
Published: May 2010

The temperature dependent band edge energy of the novel tungsten bronze type calcium barium niobate (CBN) is measured over a temperature range from 80 K to 573 K. CBN has been under investigation for serveral years and is believed to be a promising material for future applications. Czochralski‐grown, colorless single crystals from the congruently melting composition with a calcium content of 0.281 were used. A numerical fit has been applied, comparing the results of CBN to those of the well known relaxor ferroelectric strontium barium niobate (SBN). The band edge energy of CBN was found to be higher than in SBN over the whole temperature range. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The mean time between failures for an LCD panel
Authors: Wang Fu‐Kwun , Chu Tao‐Peng
Published: May 2010

The calculation of mean time between failures is very important in reliability life data analysis. For different distributions, the values of mean time between failures are always different. The two‐parameter Weibull distribution is widely used in reliability engineering. However, some distributions may offer a better fit of data. This paper aims to develop an algorithm for determining the best‐fitted distribution of a liquid crystal display panel based on the field return data. The two‐parameter and three‐parameter Weibull distributions and other distributions such as the Burr XII distribution, the Pareto distribution and the Log‐logistic distribution are compared to provide a better characterization of the life data which is based on the maximum value of all log‐likelihood functions. We also provide a goodness‐of‐fit test for the best‐fitted distribution. It is recommended that the Burr XII distribution could be used to characterize the reliability life of a liquid crystal display panel. Copyright © 2010 John Wiley & Sons, Ltd.
Li atoms attached to helium nanodroplets
Authors: Hernando Alberto , Mayol Ricardo , Pi Martí , Barranco Manuel , Kerkines Ioannis S. K. , Mavridis Aristides
Published: May 2010

We have studied helium drops doped with Li atoms within finite‐range density functional theory using Li–He pair potentials obtained by the multireference configuration interaction method combined with augmented core‐valence correlation consistent basis sets of quintuple‐zeta quality. The absorption spectrum of Li around the 2p ← 2s transition has been determined by a semiclassical approach, and by the Fourier analysis of the time‐correlation function of the Li atom in the full three‐dimensional 2Π1/2, 2Π3/2, and 2Σ1/2 potentials generated by its pairwise interaction with the helium droplet. We show that the bound–bound contribution to the absorption line is red‐shifted and more pronounced in Li@4HeN than in Li@3HeN, for which it is blue‐shifted instead, in accordance with experiments. This fact is related to the experimental appearance of a red‐shifted shoulder in the absorption line of Li attached to 4He drops that is absent when it is attached to 3He drops. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Simulating events of unknown probabilities via reverse time martingales
Authors: Łatuszyński Krzysztof , Kosmidis Ioannis , Papaspiliopoulos Omiros , Roberts Gareth O.
Published: May 2010

Let s∈(0,1) be uniquely determined but only its approximations can be obtained with a finite computational effort. Assume one aims to simulate an event of probability s. Such settings are often encountered in statistical simulations. We consider two specific examples. First, the exact simulation of non‐linear diffusions ([3]). Second, the celebrated Bernoulli factory problem ([10, 13]) of generating an f(p)‐coin given a sequence X1,X2,… of independent tosses of a p‐coin (with known f and unknown p). We describe a general framework and provide algorithms where this kind of problems can be fitted and solved. The algorithms are straightforward to implement and thus allow for effective simulation of desired events of probability s. Our methodology links the simulation problem to existence and construction of unbiased estimators. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 38, 441–452, 2011
Tof‐SIMS studies on chlorhexidine and its reaction products with sodium hypochlorite to ascertain decomposition products
Authors: Sodhi R. , Manek S. , Fillery E. , Basrani B.
Published: May 2010

The combination of sodium hypochlorite (NaOCl) and Chlorhexidine (CHX), results in the formation of a precipitate. Previous studies have been conducted to find at which concentrations the precipitate appeared and its identity. One postulate is that when CHX breaks down that one of its products is the toxic para‐chloroaniline. Both X‐Ray photoelectron spectroscopy (XPS) and Time‐of‐Flight Secondary Ion Mass Spectrometry have been used to qualify and quantify the precipitation. A problem that exists with both techniques is that the breakdown components are likely to show similar functionalities/fragments as those in CHX. Thus the presence of the breakdown components can only be surmised. For example, CHX shows peaks at 127, 153, 170 and 195 in the positive ToF‐SIMS spectrum corresponding to various molecular fragments from the parent CHX molecule arising from the breaking of the various C to N bonds. However, the major peak for chloroaniline is also that at 127. The positive ToF‐SIMS spectrum of the precipitate (after DI‐water wash) shows these fragments as well as a peak at 111 correlating with the NaOCl concentration. However, importantly, there is no evidence of the CHX parent ion on the precipitate which is present in the mass spectrum of CHX. This suggests that the fragments shown in the precipitate mass spectrum do arise from the breakdown components. This is further confirmed by mass spectra taken of the cooled precipitate and also from immiscible liquids present in the DI‐water wash solution, which showed a large increase in the peak intensity at mass 127. Copyright © 2010 John Wiley & Sons, Ltd.
Molecular SIMS imaging; spatial resolution and molecular sensitivity: have we reached the end of the road? Is there light at the end of the tunnel?
Authors: Fletcher John S. , Lockyer Nicholas P. , Vickerman John C.
Published: May 2010

This article describes how advances in instrument development facilitate the generation of high‐contrast secondary ion images by employing polyatomic ion beams and sampling in excess of the traditional static limit. The ability to perform high primary ion fluence molecular imaging with good mass resolution and spatial resolution on an improved time scale provides a new means of exploring the challenges presented by biological analysis with SIMS and provides an insight into requirements of sample preparation and data interpretation. These benefits and challenges are highlighted using examples of ToF‐SIMS imaging of rat brain and rat kidney tissue sections. Copyright © 2010 John Wiley & Sons, Ltd.
Chemical depth profiling of copper oxide film by ToF‐SIMS using Bi3++ cluster
Authors: Masudome Harumi , Abe Hiroko
Published: May 2010

In this contribution, we examined chemical information depth profiling of metal oxide film by time‐of‐flight Secondary Ion Mass Spectrometry (ToF‐SIMS). We focused on the oxidation of copper film used in a semiconductor field. As a result of the investigation of experimental conditions to analyze the chemical properties, it was shown that the molecular secondary ion intensities of [CuxOy]− were strong when using Bi3++ cluster primary ions compared with Bi+ primary ion. It was assumed that copper natural oxide film was Cu(OH)2/CuO/Cu2O/Cu layered structure, and approximately 2 nm thick. It was suggested that Cu2O became thick because of the existence of chlorine. Copyright © 2010 John Wiley & Sons, Ltd.
TOF‐SIMS analysis of media lubricant under laser irradiation for HAMR application
Authors: Ji Rong , Xu Jianwei , Liew Thomas , Zhang Jun , Xie H. Q. , Xu Baoxi , Dao T. K. L.
Published: May 2010

Heat‐assistant magnetic recording (HAMR) is a promising approach for enabling large increases in storage density of a hard disk drive. Under HAMR conditions, all hard disk components including lubricant thin film used for hard disk media should have the property of high thermal stability. This paper studies the property of a potential and current commercial lubricant under HAMR laser irradiation conditions. Through the study of the relationship between the lubricant molecular structure and the properties, guidance for new lubricant design and development has been explored. Copyright © 2010 John Wiley & Sons, Ltd.
SIMS analytical technique for PV applications
Authors: Peres P. , Merkulov A. , Desse F. , Schuhmacher M.
Published: May 2010

This paper presents analytical performances provided by SIMS tools for the development and manufacture of new solar cells. Results for two main applications are presented: trace element analysis in PV (photovoltaic) Si feedstock with detection limits from the ppm down to the ppb range (depending on the species to be analyzed) for light elements (C, O, N), main Si dopants (B, P, As) and metals; indepth distribution of main components and trace elements in CIGS thin films. Copyright © 2010 John Wiley & Sons, Ltd.
Molecular depth profiling with reactive ions, or why chemistry matters in sputtering
Authors: Houssiau L. , Mine N.
Published: May 2010

We have shown in recent papers that low‐energy Cs+ ions can be used successfully for molecular depth profiling of polymers. This paper reviews a few key experiments that provide a better understanding of the mechanisms involved in reactive ion depth profiling. It is shown that damaged polymer (polystyrene and polycarbonate) layers, initially bombarded with high‐energy gallium irradiation, can be efficiently removed by low‐energy Cs+ sputtering so that the polymer molecular signal is restored. The role played by the primary ion energy is then studied by measuring the sputtering yields at different energies on polystyrene, poly (methylmethacrylate) and polycarbonate. Depth profiles on PC were also obtained at six different Cs+ energies ranging from 150 to 1 keV. The best conditions were obtained at 200 and 250 eV, and the depth profile quality degrades above 500 eV. Finally, the negative ionization enhancement due to Cs implantation is studied by means of the Cs/Xe cosputtering method. All those experiments are consistent with a polymer cross‐linking inhibition model, due to reactions between the implanted Cs atoms and the free radicals generated by ion irradiation. The main effect in molecular depth profiling with reactive ions is, therefore, a chemical effect. Copyright © 2010 John Wiley & Sons, Ltd.
Quantification of germanium in Si1−xGex alloys by negative mode ToF‐SIMS: the interest of the full spectrum method
Authors: Py M. , Barnes J. P. , Hartmann J. M.
Published: May 2010

The abundance of work on Si1−xGex‐based devices demonstrates the importance of compositional characterization of such materials. The matrix effect in SIMS limits accurate concentration determination to a certain range of x. In previous works it was shown that this limitation can be surpassed by following MCs2+ secondary ions which allows Ge concentration to be quantified in the x = 0.05 to 0.85 range. Here an alternative protocol for Ge quantification using negative ion detection in ToF‐SIMS is investigated. The negative secondary ion emission from epitaxially grown Si1−xGex was studied with a TOF SIMS V from ION‐TOF GmbH. Although a fair linear correlation between ion ratios and Ge/Si layer composition ratios was found, non linear behavior was still present, hampering the precision of the method. Therefore, an alternative protocol was investigated, the full‐spectrum method, which states proportionality between composition of the secondary ion beam and that of the actual material. SiGe layers were depth profiled with a long cycle time to allow detection of SinGem clusters up to n, m = 6. The Ge (Si) composition of the secondary ion beam was calculated and compared with the composition as determined by XRD. Excellent linear correlation is observed. The repeatability of the method and the influence of the sputter beam energy on the secondary ion beam composition were also studied. Copyright © 2010 John Wiley & Sons, Ltd.
Using Testlet Response Theory to analyze data from a survey of attitude change among breast cancer survivors
Authors: Wang Xiaohui , Baldwin Su , Wainer Howard , Bradlow Eric T. , Reeve Bryce B. , Smith Ashley W. , Bellizzi Keith M. , Baumgartner Kathy B.
Published: May 2010

In this paper we examine alternative measurement models for fitting data from health surveys. We show why a testlet‐based latent trait model that includes covariate information, embedded within a fully Bayesian framework, can allow multiple simultaneous inferences and aid interpretation. We illustrate our approach with a survey of breast cancer survivors that reveals how the attitudes of those patients change after diagnosis toward a focus on appreciating the here‐and‐now, and away from consideration of longer‐term goals. Using the covariate information, we also show the extent to which individual‐level variables such as race, age and Tamoxifen treatment are related to a patient's change in attitude.

The major contribution of this research is to demonstrate the use of a hierarchical Bayesian IRT model with covariates in this application area; hence a novel case study, and one that is certainly closely aligned with but distinct from the educational testing applications that have made IRT the dominant test scoring model. Copyright © 2010 John Wiley & Sons, Ltd.
Social capital and psychological distress of elderly in Japanese rural communities
Authors: Hamano Tsuyoshi , Yamasaki Masayuki , Fujisawa Yoshikazu , Ito Katsuhisa , Nabika Toru , Shiwaku Kuninori
Published: May 2010

The growing recognition of the social determinants of health has stimulated research on social capital and mental health. We explored new empirical evidence regarding whether social capital was a determinant of psychological distress. Baseline surveys examining psychological distress were conducted in two towns in 2006–2007 (participation rates for those aged 20 or over were 27.6 per cent, 6.1 per cent). We also conducted follow‐up surveys in 2008 to capture the social capital measured by trust. By linking these data and excluding the missing data, 141 males and 234 females remained as the subjects of our study. Results showed that the odds ratios of psychological distress was higher in groups with low social capital measured by trust (odds ratio 2.17; 95 per cent CI, 1.40–3.36), than those in groups with high social capital. Further, we examined the interaction effect of social capital and social support. The odds ratios of psychological distress was higher in groups with some social support/lower trust (odds ratio 2.21; 95 per cent CI, 1.36–3.58) or no social support/lower trust (odds ratio 2.07; 95 per cent CI, 1.06–4.05), than those in groups with some social support/higher trust. These findings reinforce the hypothesized discussion regarding pathways from social capital to psychological distress via supportive relationships. Copyright © 2010 John Wiley & Sons, Ltd.
Excitonic interaction: another photophysical process for fluorescence‐controlled nucleic acid sensing
Authors: Okamoto Akimitsu
Published: May 2010

An excitonic interaction caused by the H‐aggregation of fluorescent dyes is a new type of useful photophysical process for fluorescence‐controlled nucleic acid sensing. We designed a fluorescence‐labeled nucleotide in which two thiazole orange dyes were linked covalently. A DNA strand containing this fluorescence‐labeled nucleotide showed absorption at 480 nm before hybridization, whereas an absorption band at 510 nm became predominant when the DNA was hybridized with the complementary strand. The shift in the absorption bands shows the existence of an excitonic interaction between dyes in the nucleotide, and as a result, emission from the doubly thiazole orange‐labeled DNA was well controlled. This clear change in fluorescence intensity depending on hybridization is applicable to multicolor RNA imaging in living cells. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 188–196; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000003
Methane storage in porous metal−organic frameworks: current records and future perspectives
Authors: Zhou Wei
Published: May 2010

Porous metal−organic frameworks (MOFs) are a novel family of physisorptive materials exhibiting great potential for methane storage applications. Several MOF compounds have been reported to exhibit high methane uptake at room temperature and modest pressure, with a few even surpassing the target for material‐based, adsorbed methane storage set by U.S. Department of Energy. Here we briefly review the rapid research progress in recent years on methane storage in MOFs and highlight the current record holders. We also discuss the current understanding of the methane storage mechanism in these fascinating materials and outline the future directions in this field. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 200–204; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000004
PM10‐biogenic fraction drives the seasonal variation of proinflammatory response in A549 cells
Authors: Camatini Marina , Corvaja Viviana , Pezzolato Eleonora , Mantecca Paride , Gualtieri Maurizio
Published: May 2010

PM10 was collected in a Milan urban site, representative of the city air quality, during winter and summer 2006. Mean daily PM10 concentration was 48 μg m−3 during summer and 148 μg m−3 during winter. Particles collected on Teflon filters were chemically characterized and the endotoxin content determined by the LAL test. PM10‐induced cell toxicity, assessed with MTT and LDH methods, and proinflammatory potential, monitored by IL‐6 and IL‐8 cytokines release, were investigated on the human alveolar epithelial cell line A549 exposed to increasing doses of PM. Besides untreated cells, exposure to inert carbon particles (2–12 μm) was also used as additional control. Both cell toxicity and proinflammatory potency resulted to be higher for summer PM10 with respect of winter PM10, with IL‐6 showing the highest dose‐dependent release. The relevance of biogenic components adsorbed onto PM10 in eliciting the proinflammatory mediators release was investigated by inhibition experiments. Polymixin B (Poly) was used to inhibit particle‐bind LPS while Toll‐like receptor‐2 antibody (a‐TLR2) to specifically block the activation of this receptor. While cell viability was not modulated in cells coexposed to PM10 and Poly or a‐TLR2 or both, inflammatory response did it, with IL‐6 release being the most inhibited. In conclusion, Milan PM10‐induced seasonal‐dependent biological effects, with summer particles showing higher cytotoxic and proinflammatory potential. Cytotoxicity seemed to be unaffected by the PM biogenic components, while inflammation was significantly reduced after the inhibition of some biogenic activated pathways. Besides, the PM‐associated biogenic activity does not entirely justify the PM‐induced inflammatory effects. © 2010 Wiley Periodicals, Inc. Environ Toxicol 2012.
Omphalocele: comparison of outcome following prenatal or postnatal diagnosis
Authors: Cohen‐Overbeek T. E. , Tong W. H. , Hatzmann T. R. , Wilms J. F. , Govaerts L. C. P. , Galjaard R. J. H. , Steegers E. A. P. , Hop W. C. J. , Wladimiroff J. W. , Tibboel D.
Published: May 2010

Objectives

To assess the impact of prenatal compared with postnatal diagnosis on outcome for liveborn infants with an isolated or with a non‐isolated omphalocele.

Methods

This was a retrospective analysis of 101 prenatally and 45 postnatally diagnosed cases of omphalocele. Cases were collected from the ultrasound database of the Division of Obstetrics and Prenatal Medicine and the patient database of the Department of Pediatric Surgery.

Results

Following confirmation at delivery or autopsy, prenatally diagnosed omphaloceles included 21 isolated cases, 44 non‐isolated cases with a normal karyotype and 36 non‐isolated cases with an abnormal karyotype. Of the prenatally diagnosed apparently isolated cases (n = 31), 12 (39%; 95% CI, 22–58%) revealed associated anomalies after delivery. Liveborn infants with an isolated omphalocele had significantly worse short‐term morbidity following prenatal diagnosis (n = 14) compared with diagnosis at birth (n = 29), having a lower gestational age at delivery, lower Apgar scores, longer duration of ventilation and parenteral nutrition, more readmissions and a longer hospital stay. The prenatally diagnosed subset contained more infants with a giant omphalocele (9/14 vs. 3/29, P = 0.001) and liver herniation (8/14 vs. 6/29, P = 0.02). The outcome of liveborn infants with a non‐isolated omphalocele diagnosed prenatally (n = 17) was not different from that of those diagnosed at birth (n = 16), except for a greater need for ventilation and parenteral nutrition in the prenatal subset.

Conclusion

When counseling patients with a prenatal diagnosis of isolated omphalocele, it is important to remember that over one third could turn out to have associated anomalies. Liveborn infants with an isolated omphalocele detected prenatally have worse short‐term morbidity than do cases detected at birth. Those with non‐isolated omphaloceles detected prenatally have an increased need for ventilation and parenteral nutrition compared with those detected at birth. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Repeat expansion diseases: when a good RNA turns bad
Authors: Dickson Alexa M. , Wilusz Carol J.
Published: May 2010

An increasing number of dominantly inherited diseases have now been linked with expansion of short repeats within specific genes. Although some of these expansions affect protein function or result in haploinsufficiency, a significant portion cause pathogenesis through production of toxic RNA molecules that alter cellular metabolism. In this review, we examine the criteria that influence toxicity of these mutant RNAs and discuss new developments in therapeutic approaches. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry

RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

RNA Processing > Splicing Regulation/Alternative Splicing

RNA in Disease and Development > RNA in Disease
Relationship between gonadal steroid hormones and vulvar bleeding in southern tamandua, Tamandua tetradactyla
Authors: Kusuda Satoshi , Endoh Tomoko , Tanaka Hiroyuki , Adachi Itsuki , Doi Osamu , Kimura Junpei
Published: May 2010

This study aimed at demonstrating the profiles of circulating gonadal steroid hormones during the estrous cycle and pregnancy in a southern tamandua (Tamandua tetradactyla). Additionally, this study clarified the relationship between vulvar bleeding and hormonal changes. The concentrations of serum progesterone (P4) and estradiol‐17β (E2) were determined by enzyme immunoassays. Serum P4 and E2 concentrations changed cyclically and the estrous cycle length (±SD) based on the E2 cycles was 44.3±4.5 days. Vulvar bleeding started to be seen at the decreasing of P4. The cycle length for vulvar bleeding was 43.3±4.2 days. Interval from the first day of bleeding to the peak of E2 concentration was 23.1±3.1 days. Serum P4 during pregnancy remained high and E2 increased 8 weeks after conception and remained high until parturition. The female delivered normally after a 165 day‐pregnancy period and reared the offspring well. Approximately 3 weeks after parturition, serum E2 and P4 cycles resumed. Visual bleeding may be useful as a real‐time indicator for understanding the ovarian cycle of southern tamanduas, and estrus could be expected approximately 3 weeks after the first bleeding. Zoo Biol 30:212–217, 2011. © 2010 Wiley‐Liss, Inc.
Gynaecologists estimate and experience laparoscopic hysterectomy as more difficult compared with abdominal hysterectomy
Authors: Nieboer Theodoor E. , Spaanderman Marc E. A. , Bongers Marlies Y. , Vierhout Mark E. , Kluivers Kirsten B.
Published: May 2010

The level of difficulty of various types of hysterectomy differs and may influence the choice of either approach. When surgeons consider one specific approach to hysterectomy as more difficult, they may be reluctant to perform this type of hysterectomy. The main objective of this study was to investigate the potential different levels of difficulty for laparoscopic and abdominal hysterectomy. Furthermore, the accuracy of estimating the level of difficulty was examined. In a randomized controlled trial between laparoscopic hysterectomy (LH) and abdominal hysterectomy (AH), gynaecologists were asked to record the preoperatively estimated and postoperatively experienced level of difficulty on a Visual Analogue Scale (VAS). Differences between LH and AH were examined and the correlation between the estimated uterine weight on bimanual palpation and the actual uterine weight was calculated. A difference on the VAS of three points or more (ΔVAS ≥ 3) was considered clinically relevant. In 72 out of 76 cases, both VAS scores were recorded. LH was estimated and experienced as significantly more difficult as compared with AH. In 13 (18%) cases, ΔVAS was ≥3, equally distributed between LH (n = 6) and AH (n = 7). Eleven of these 13 cases had a positive ΔVAS ≥3, meaning that surgery was experienced as more difficult than it was estimated. Surgeon’s estimation of uterine size correlated well with the actual uterine weight. LH is considered as more difficult than AH, which might be a reason for its slow implementation. In a large proportion of cases, gynaecologists seem to be able to estimate the level of difficulty of hysterectomy accurately.
Postoperative Hypoxemia in Orthopedic Patients with Obstructive Sleep Apnea
Authors: Liu Spencer S. , Chisholm Mary F. , Ngeow Justin , John Raymond S. , Shaw Pamela , Ma Yan , Memtsoudis Stavros G.
Published: May 2010

Criteria to determine which patients with obstructive sleep apnea (OSA) require intensive postoperative monitoring are lacking. Our postoperative OSA patients are all intensively monitored in the PACU and can provide such data. Thus, we reviewed patient records to determine incidence and risk factors for postoperative hypoxemia in OSA patients and subsequent association with postoperative complications. Five hundred twenty-seven charts of patients with OSA based on preoperative ICD-9 codes were reviewed for outcomes including episodes of hypoxemia and hypercarbia. Univariate analysis, logistic regression, and propensity analysis were performed to determine independent risk factors for hypoxemia and association with adverse outcomes. Thirty-three and 11 percent of these patients developed hypoxemia or hypercarbia. Risk factors for hypoxemia were hypercarbia, home bronchodilator use, BMI ≥35, and estimated blood loss ≥250 ml. Patients with hypoxemia had significantly more respiratory interventions and increased intensity of care. Patients with hypoxemia had significantly increased length of stay and risk of wound infections. Severe hypoxemia was associated with significantly more interventions than mild hypoxemia. Propensity analysis confirmed significant association of hypoxemia with adverse outcomes after adjustment for pre-existing risk factors. We conclude that postoperative hypoxemia in OSA patients is associated with adverse outcomes. Risk factors for hypoxemia were identified to guide allocation of monitoring resources to high-risk patients.
Dissimilar Properties of Vaccenic Versus Elaidic Acid in β‐Oxidation Activities and Gene Regulation in Rat Liver Cells
Authors: Du Zhen‐Yu , Degrace Pascal , Gresti Joseph , Loreau Olivier , Clouet Pierre
Published: May 2010

Vaccenic acid (trans‐11‐C18:1) chemically resembles elaidic acid (trans‐9‐C18:1) which is assumed to increase the risk of cardiovascular diseases, and thus could exert similar effects. Possible different oxidation rates of vaccenic versus elaidic acid were checked in muscles and liver, and through related gene expression in normal rat liver cells. In hepatic mitochondria, carnitine palmitoyltransferase (CPT) I exhibited comparable activity rates with both trans‐isomers. CPT II activity was 30% greater (P < 0.05) with vaccenic than with elaidic acid as nonesterified fatty acids (NEFAs) or acyl‐CoAs. Activity of the first β‐oxidation step was similar between the isomers in all the tissue slices and liver extracts assayed. Respiration rates were comparable with both trans‐isomers as NEFAs in various liver extracts, but were 30% greater (P < 0.05) with vaccenoyl‐CoA than with elaidoyl‐CoA in liver mitochondria. Vaccenic acid was oxidised 25% more (P < 0.05) by liver peroxisomes than elaidic acid. In hepatocytes cultured with trans‐ and corresponding cis‐C18:1 isomers, gene expression of CPT I, hydroxyacyl‐CoA dehydrogenase and hydroxymethylglutaryl‐CoA synthase was at least 100% increased (P < 0.05), but was unchanged with vaccenic acid, relative to controls. In conclusion, the position and geometry of the double bonds in acyl chains are suggested to confer on vaccenic and elaidic acid specific biochemical properties that might differently affect their fates in tissues.
Pandemic Influenza A (H1N1) 2009: Chest Radiographic Findings from 147 Proven Cases in the Montreal Area
Authors: Semionov Alexandre , Tremblay Cécile , Samson Louise , Chandonnet Martin , Chalaoui Jean , Chartrand-Lefebvre Carl
Published: May 2010

Objective

To describe chest radiographic findings in patients with isolated and complicated acute novel influenza A (H1N1) virus infection.

Methods

Retrospective study of 147 patients (64 men, mean age 41) with reverse-transcriptase polymerase chain reaction confirmed acute influenza A (H1N1) infection, who also had a chest radiograph <72 hours of viral specimen collection. Radiographs were analysed for acute findings. A correlation with bacterial cultures results was performed. The unpaired 2-sample equal-variance Student t test was applied to continuous variables and the Pearson χ2 test of association to discrete variables.

Results

In 71% of cases, chest radiograph was normal. The presence of acute imaging findings was associated with older age ( P < .05), increased number of comorbidities (most commonly, chronic obstructive pulmonary disease, diabetes, asthma) ( P < .05), higher rate of hospitalization ( P < .05) and intensive care unit admission, and increased mortality. Predominant acute radiographic finding in isolated influenza A (H1N1) was alveolar opacity (88%), either unifocal or multifocal, most often in the lower lobes. In the subgroup of patients with positive imaging findings and for whom nonviral microbiologic data was available, 62% had superimposed bacterial or fungal infection.

Conclusion

In the majority of patients with acute influenza A (H1N1) infection, the chest radiograph is normal. Acute imaging findings are associated with older age, an increased number of comorbidities, and a higher rate of complications and mortality. The predominant radiographic finding of isolated primary influenza A (H1N1) infection is alveolar opacity. Superimposed bacterial infection is frequent and must be excluded in patients with abnormal imaging.