bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo electroporation and ubiquitin promoter – a protocol for sustained gene expression in the lung
Authors: Gazdhar Amiq , Bilici Murat , Pierog Jaroslaw , Ayuni Erick L , Gugger Mathias , Wetterwald Antoinette , Cecchini Marco , Schmid Ralph Alexander 
Published: May 2006

AbstractBackgroundGene therapy applications require safe and efficient methods for gene transfer. Present methods are restricted by low efficiency and short duration of transgene expression. In vivo electroporation, a physical method of gene transfer, has evolved as an efficient method in recent years. We present a protocol involving electroporation combined with a long‐acting promoter system for gene transfer to the lung.MethodsThe study was designed to evaluate electroporation‐mediated gene transfer to the lung and to analyze a promoter system that allows prolonged transgene expression. A volume of 250 µl of purified plasmid DNA suspended in water was instilled into the left lung of anesthetized rats, followed by left thoracotomy and electroporation of the exposed left lung. Plasmids pCiKlux and pUblux expressing luciferase under the control of the cytomegalovirus immediate‐early promoter/enhancer (CMV‐IEPE) or human polyubiquitin c (Ubc) promoter were used. Electroporation conditions were optimized with four pulses (200 V/cm, 20 ms at 1 Hz) using flat plate electrodes. The animals were sacrificed at different time points up to day 40, after gene transfer. Gene expression was detected and quantified by bioluminescent reporter imaging (BLI) and relative light units per milligram of protein (RLU/mg) was measured by luminometer for p.Pyralis luciferase and immunohistochemistry, using an anti‐luciferase antibody.ResultsGene expression with the CMV‐IEPE promoter was highest 24 h after gene transfer (2932 ± 249.4 relative light units (RLU)/mg of total lung protein) and returned to baseline by day 3 (382 ± 318 RLU/mg of total lung protein); at day 5 no expression was detected, whereas gene expression under the Ubc promoter was detected up to day 40 (1989 ± 710 RLU/mg of total lung protein) with a peak at day 20 (2821 ± 2092 RLU/mg of total lung protein). Arterial blood gas (PaO2), histological assessment and cytokine measurements showed no significant toxicity neither at day 1 nor at day 40.ConclusionsThese results provide evidence that in vivo electroporation is a safe and effective tool for non‐viral gene delivery to the lungs. If this method is used in combination with a long‐acting promoter system, sustained transgene expression can be achieved. Copyright © 2006 John Wiley & Sons, Ltd.
Comparative model of EutB from coenzyme B12‐dependent ethanolamine ammonia‐lyase reveals a β8α8, TIM‐barrel fold and radical catalytic site structural features
Authors: Sun Li , Warncke Kurt 
Published: May 2006

AbstractThe structure of the EutB protein from Salmonella typhimurium, which contains the active site of the coenzyme B12 (adenosylcobalamin)‐dependent enzyme, ethanolamine ammonia‐lyase, has been predicted by using structural proteomics techniques of comparative modelling. The 453‐residue EutB protein displays no significant sequence identity with proteins of known structure. Therefore, secondary structure prediction and fold recognition algorithms were used to identify templates. Multiple three‐dimensional template matching (threading) servers identified predominantly β8α8, TIM‐barrel proteins, and in particular, the large subunits of diol dehydratase (PDB: 1eex:A, 1dio:A) and glycerol dehydratase (PDB: 1mmf:A), as templates. Consistent with this identification, the dehydratases are, like ethanolamine ammonia‐lyase, Class II coenzyme B12‐dependent enzymes. Model building was performed by using MODELLER. Models were evaluated by using different programs, including PROCHECK and VERIFY3D. The results identify a β8α8, TIM‐barrel fold for EutB. The β8α8, TIM‐barrel fold is consistent with a central role of the α/β‐barrel structures in radical catalysis conducted by the coenzyme B12‐ and S‐adenosylmethionine‐dependent (radical SAM) enzyme superfamilies. The EutB model and multiple sequence alignment among ethanolamine ammonia‐lyase, diol dehydratase, and glycerol dehydratase from different species reveal the following protein structural features: (1) a “cap” loop segment that closes the N‐terminal region of the barrel, (2) a common cobalamin cofactor binding topography at the C‐terminal region of the barrel, and (3) a β‐barrel‐internal guanidinium group from EutB R160 that overlaps the position of the active‐site potassium ion found in the dehydratases. R160 is proposed to have a role in substrate binding and radical catalysis. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Opal–AgI photonic crystal controlled by the superionic phase transition
Authors: Il'inskii Alexander V. , Aliev Rasul A. , Kurdyukov Dmitry A. , Sharenkova Nataliya V. , Shadrin Evgenii B. , Golubev Valery G. 
Published: May 2006

AbstractA three‐dimensional photonic crystal based on an opal–AgI composite was fabricated using a high‐pressure melt technique. It is shown that the semiconductor–superionic conductor phase transition in AgI controls electronic and optical properties of the composite. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of ramping anneals under inert or oxidizing ambient on the formation of oxygen precipitate denuded zone in nitrogen‐doped Czochralski silicon wafers
Authors: Ma Xiangyang , Tian Daxi , Gong Longfei , Yang Deren 
Published: May 2006

AbstractThe formation of an oxygen precipitate denuded zone in nitrogen‐doped Czochralski (NCZ) silicon and conventional CZ silicon subjected to ramping anneals under Ar or O2 ambient has been investigated. It is revealed that the nitrogen doping is able to homogenize substantially the density of bulk micro‐defects associated with oxygen precipitation in the silicon wafers with different thermal histories and initial oxygen contents. The oxygen precipitate denuded zone is only formed in specimens subjected to the ramping anneal under Ar ambient. It is believed that the ramping anneal under Ar ambient could be an alternative intrinsic gettering process for NCZ silicon wafers, while it is not very appropriate for conventional CZ silicon wafers. Furthermore, it is somewhat unexpected that oxygen precipitation during the ramping anneal under O2 ambient is not suppressed but slightly enhanced in comparison with that during the ramping anneal under Ar ambient, the reason for which is tentatively explained. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport properties of the two‐dimensional electron gas in GaN/AlGaN heterostructures grown by ammonia molecular‐beam epitaxy
Authors: Pogosov A. G. , Budantsev M. V. , Lavrov R. A. , Mansurov V. G. , Nikitin A. Yu. , Preobrazhenskii V. V. , Zhuravlev K. S. 
Published: May 2006

AbstractTransport properties of the two‐dimensional electron gas in AlGaN/GaN heterostructures grown by ammonia molecular‐beam epitaxy are experimentally investigated. Conventional Hall and Shubnikov–de Haas measurements as well as investigations of quantum transport phenomena are reported. It is found that negative magnetoresistance (NMR) caused by weak localization demonstrates an unusual behavior at low temperature (1.8 K). The observed NMR cannot be described by the ordinary theory of quantum corrections to conductivity based on a single phase breaking time τϕ . The anomalous NMR behavior can be explained by the presence of two occupied quantum subbands, characterized by their own phase breaking times τ ϕ 1 and τ ϕ 2. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical simulation of impedance and admittance of OLEDs
Authors: Nguyen N. D. , Schmeits M. 
Published: May 2006

AbstractThe electrical characteristics of organic light‐emitting devices are calculated for the dc and ac regimes by numerically solving the basic semiconductor equations under steady‐state and small‐signal conditions. For a given structure, the dc and ac electric potential and electric field, the electron and hole concentrations, as well as the different components of the current density are obtained as function of the one‐dimensional spatial coordinate. This approach allows a detailed microscopic description of the dependencies of these quantities on the applied steady‐state voltage V0 and the frequency of the modulating voltage. The final output consists in the frequency‐dependent complex admittance and impedance of the device, the real and imaginary parts of which are the experimentally‐available data. As a typical example, we show the results for a two‐layer structure where α‐NPD is the hole‐transporting material and Alq3 the electron‐transporting material. The anode is made of ITO and Al/LiF composes the cathode. The admittance and impedance curves, yielded by the numerical simulation as functions of the modulation frequency, are fitted by an equivalent electrical circuit, the elements of which are resistances and capacitances. The number of components depends on the structure composition and on the applied steady‐state voltage. We show that each element can be associated with a particular region of the device. This allows to correlate the dependence of each feature of the admittance and impedance curves with one or several parameters describing the material system. Such an analysis can be useful for the inverse approach, where, starting from measurements of the electrical ac characteristics, the aim is to get information on the microscopic mechanisms which contribute to the electrical conduction of the device. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental evidence for Drude‐Boltzmann‐like transport in a two‐dimensional electron gas in an AlGaN/GaN heterostructure
Authors: Chen Jing‐Han , Lin Jyun‐Ying , Tsai Jung‐Kai , Park Hun , Kim Gil‐Ho , Ahn Jungseok , Cho Hyun‐Ick , Lee Eun‐Jin , Lee Jung‐Hee , Liang C.‐T. , Chen Y. F. 
Published: May 2006

AbstractWe report transport measurements on an AlGaN/GaN two‐dimensional electron gas (2DEG) as a function of magnetic field B over a wide range of temperature (0.3 K ≤ T ≤ 80 K). At T = 20 K, the electron‐electron interaction effect in the diffusive limit is expected to be strongly suppressed, causing the longitudinal resistivity ρxx (B ) te be nomially B ‐independent at low field B < 6 T. At T = 80 K, ρxx (B ) is nomially B ‐independent for B < 13 T. The range of nominally B ‐independent ρxx increases with increasing temperature due to the suppression of electron‐electron interaction effects. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of low resistance nonalloyed ohmic contacts to p‐type GaN by KrF laser irradiation
Authors: Oh Min‐Suk , Jang Ja‐Soon , Kim Sang‐Ho , Seong Tae‐Yeon 
Published: May 2006

AbstractKrF excimer‐laser‐irradiation treatment in a N2 atmosphere is introduced to improve the electrical properties of p ‐type GaN and so to form low resistance nonalloyed Ni/Au ohmic contacts. The as‐grown sample exhibits non‐linear electrical behavior. However, the samples laser‐annealed in N2 ambient become ohmic with specific contact resistance of 8.9(±0.6)×10–5 Ωcm2. Hall measurement and current‐voltage‐temperature results show that the laser irradiation is effective in increasing a hole concentration in the surface region of p ‐GaN, leading to both the enhancement in field emission and the reduction of the effective Schottky barrier heights at the metal‐semiconductor interface. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Reduced residual stress in GaN grown on 3c‐SiC/Si(111) templates formed by C+‐ion implantation
Authors: Kobayashi T. , Sawazaki N. , Cho M. S. , Hashimoto A. , Yamamoto A. , Ito Y. 
Published: May 2006

AbstractThis paper reports the residual tensile stress in GaN grown on 3c‐SiC/Si template formed by C+‐ion implantation into Si(111). A GaN layer is grown using MOVPE method with the conventional two‐step growth. The residual tensile stress is dependent on the fabrication conditions of the template, such as substrate temperature for implantation, acceleration voltage of C+‐ions, temperature and time for the post‐implantation annealing of Si wafers. It is found that the substrate temperature during implantation is a predominant factor. The residual stress in GaN layer is reduced from 1.3 to 0.45 GPa when the substrate temperature during implantation is changed from 400 to 600 ºC. The stress is also decreased by increasing accelerating voltage for implantation and post‐implantation annealing time. The residual tensile stress of 0.45 GPa is the lowest one ever reported for GaN on Si. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature current‐voltage characterisation of MOCVD grown InGaN/GaN MQW LEDs
Authors: Moldovan Grigore , Phillips Andrew , Thrush E. J. , Humphreys Colin J. 
Published: May 2006

AbstractA methodology of temperature current‐voltage characterisation for blue GaN‐based LED is described, with emphasis on artefacts arising from self‐heating at high forward currents and voltage transients at low forward currents. Examples of LEDs with Al2O3 and SiC substrates are discussed, with methods of accounting and avoiding these errors. For the devices studied here it is found that tunnelling dominates the charge transport and that two parallel conduction pathways are present. A method of interpretation of extracted data is also presented, in the context of desired device performance. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamic polarization rotation in pump‐and‐probe transients of anisotropically strained M ‐plane GaN films on LiAlO2
Authors: Omae K. , Flissikowski T. , Misra P. , Brandt O. , Grahn H. T. , Kojima K. , Kawakami Y. 
Published: May 2006

AbstractWe report on the dynamical polarization rotation of anisotropically strained M ‐plane GaN films on LiAlO2. Since M ‐plane GaN films on LiAlO2 exhibit a large anisotropic in‐plane strain, the wavefunction of the highest (second highest) valence band becomes completely |x 〉 (|z 〉) like, where x and z are parallel to the a ‐ and c ‐axis, respectively, of the wurtzite crystal structure. Therefore, the absorption spectra for M ‐plane GaN depend strongly on the polarization of the incoming light beam. As a result, a static rotation of the polarization vector appears after transmission of linearly polarized light. This rotation can be dynamically controlled by a selective bleaching of the absorption of only one or both valence bands using carriers excited by additional pumping. For an incoming polarization angle of 60°, the maximum dynamic rotation reaches 35°, while the maximum static polarization rotation is about 40°. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carrier capture and escape processes in (In,Ga)N single‐quantum‐well diode under forward bias condition by photoluminescence spectroscopy
Authors: Satake A. , Soejima K. , Aizawa H. , Fujiwara K. 
Published: May 2006

AbstractCarrier capture and escape processes in the super‐bright green (In,Ga)N single‐quantum‐well (SQW) light‐emitting diode (LED) has been studied by photoluminescence (PL) spectroscopy under reverse and forward bias conditions. The PL spectra were measured at 20 K under excitation photon energies above and below the bandgap energy of GaN barrier layers. The PL spectra under both excitation conditions show green emission from the (In,Ga)N SQW layer. The wavelength‐integrated PL intensity changes drastically depending on the applied bias voltage. For the excitation below the bandgap energy of GaN (direct excitation), the PL intensity increases with increasing the forward bias voltage up to +2 V and significant reduction of the PL intensity is observed with further increase of the forward bias voltage. On the other hand, for the excitation above the bandgap energy of GaN (indirect excitation), the PL intensity rapidly increases up to +2 V, decreases once, increases again with the maximum value at +3.25 V, and drastically decreases again. These differences of the PL intensity variation reflect carrier escape and capture processes. That is, for the direct excitation condition, the PL intensity variation indicates the effect of the electric field on the radiative recombination and the carrier escape processes. In contrast, for the indirect excitation condition, it indicates the carrier transfer and capture processes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Barrier‐to‐well carrier dynamics of InGaN/GaN multi‐quantum‐wells grown by plasma assisted MBE on bulk GaN substrates
Authors: Korona K. P. , Skierbiszewski C. , Siekacz M. , Feduniewicz A. , Suski T. , Franssen G. , Grzegory I. , Borysiuk J. , Leszczyński M. 
Published: May 2006

AbstractWe present study of carrier dynamics in GaInN/GaN multi quantum wells (MQWs) with screened electric fields. The PL emission showed clearly resolved peaks emitted from the Ga0.9In0.1N QWs (at about 3.1 eV, FWHM 30‐50 meV). Two samples with 2.5‐nm‐QWs and 4‐nm‐QWs showed decay‐times of 1.1 ns and 2.3 ns. The decay‐rates in the barriers were thermally activated, activation energies were 21 meV and 46 meV, for the 2.5‐nm‐QWs and 4‐nm‐QWs structures, respectively. Analysis of correlation between rising‐rates of the MQW PL and the decay‐rates of the barriers PL confirmed increase of transport through barrier. The MQW PL energy changed with time. The phenomenon was due to trapping of excitons on donors or localization in potential minima. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum kinetic theory of phonon‐assisted carrier transitions in nitride based quantum‐dot systems
Authors: Seebeck J. , Nielsen T.R. , Lorke M. , Gartner P. , Jahnke F. 
Published: May 2006

AbstractA microscopic theory for the interaction of carriers with LO phonons is used to study ultrafast capture and relaxation dynamics in semiconductor quantum dots. Energy renormalization due to carrier‐phonon interaction leads to quantum‐dot polarons which are included in quantum‐kinetic equations to describe scattering processes. Our results show efficient capture and relaxation processes. For an InGaN quantumdot system the influence of the strong built‐in electrostatic field on the carrier dynamics is investigated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leveraging disposable instrumentation to reduce coverage collection overhead
Authors: Chilakamarri Kalyan‐Ram , Elbaum Sebastian 
Published: May 2006

AbstractTesters use coverage data for test suite quality assessment, stopping criteria definition, and effort allocation. However, as the complexity of products and testing processes increases, the cost of coverage data collection may grow significantly, jeopardizing its potential application. To mitigate this problem this paper presents the concept of ‘disposable coverage instrumentation’—coverage instrumentation that is removed after its execution—through two techniques: local disposal, and collective disposal. A Java virtual machine was extended to support these techniques, and their potential is shown through two studies utilizing the Specjvm98 and Specjbb2000 benchmarks. The results indicate that the techniques can reduce coverage collection overhead by an order of magnitude over state‐of‐the‐art techniques. Copyright © 2006 John Wiley & Sons, Ltd.
One‐stage Sigmoid Colon Resection for Perforated Sigmoid Diverticulitis (Hinchey Stages III and IV)
Authors: Richter Sven , Lindemann Werner , Kollmar Otto , Pistorius Georg A. , Maurer Christoph A. , Schilling Martin K. 
Published: May 2006

AbstractIntroductionGuidelines for the treatment of complicated sigmoid diverticulitis recommend Hartmann’s procedure or anastomosis with protective colostomy for Hinchey stage III diverticulitis and Hartmann’s procedure only for Hinchey stage IV diverticulitis. We evaluated the outcome of patients with perforated sigmoid diverticulitis Hinchey III/IV undergoing one‐stage colon resection and primary anastomosis without protective colostomy.MethodsAfter implementation of a protocol to treat Hinchey III/IV diverticulitis with primary anastomosis without protective ileocolostomy, the patients’ data were recorded prospectively between August 2001 and August 2003 and analyzed retrospectively from a computer‐related database.ResultsOf 41 patients, 34 (81%%) underwent one‐stage sigmoid resection and primary anastomosis, 3 of 41 patients (7%%) underwent primary anatomosis with protective ileostomy, and 5 of 41 patients (12%%) had a Hartmann’s procedure. The mortality was 11%% in patients undergoing primary anastomosis and 60%% in patients with Hartmann’s procedure. The relative risk of co‐morbidity factors for lethal outcome after sigmoid resection was 6.94 for preceding operations, 3.75 for renal failure or renal transplantation, and 3.25 for immunosuppression.ConclusionsOne‐stage sigmoid resection and primary anastomosis can be performed safely in nearly 90%% of all patients with perforated sigmoid diverticulitis (Hinchey III/IV) by surgeons of different training levels. Patients with immunosuppression, chronic renal failure, liver cirrhosis, or previous organ transplantation or complex cardiovascular reconstructive procedures have a significantly increased risk of dying after sigmoid resection for perforated diverticulitis.
Raised plasma adiponectin levels in type 1 diabetic pregnancies
Authors: Randeva Harpal S. , Vatish Manu , Tan Bee K. , Qureshi Zubair , Boovalingam Padmabushan , Lewandowski Krzysztof C. , O’Hare Paul 
Published: May 2006

SummaryObjectives  Adiponectin has antidiabetic properties. Our aim was to determine plasma adiponectin levels during pregnancy and postpartum (PP), in women with type 1 diabetic mellitus (T1DM) and nondiabetic (ND) women.Patients and Methods  Fasting plasma adiponectin and leptin levels were measured in 20 ND and 19 T1DM women, at 20 and 30 weeks’ gestation, and 9 months’ PP. Insulin measurements were made in ND women.Results  In both groups, after accounting for body mass index (BMI), leptin levels increased during pregnancy (P < 0·01) and were significantly higher than PP (P < 0·001). However, no significant differences in leptin levels were noted between both groups at any stage (P = 0·46). Conversely, adiponectin levels were higher in T1DM at all stages of the study (P < 0·001). A significant fall in adiponectin levels was seen between 20 and 30 weeks’ gestation in both groups (ND: P < 0·001; T1DM: P < 0·05); however, this decrease was attenuated in the T1DM group. Adiponectin levels PP were significantly higher than at 30 weeks (ND: P < 0·001; T1DM: P < 0·001). Furthermore, in T1DM, adiponectin appeared to correlate negatively with leptin, but only reached significance PP (r = –0·46, P < 0·001). In the ND group, adiponectin correlated negatively with both leptin (PP: r = −0·56, P < 0·0001) and insulin (P < 0·005).Conclusions  Higher adiponectin levels were noted in T1DM throughout gestation compared to ND pregnancies, with no difference in leptin levels. The significance of these findings needs to be determined.