bluuebunny/crossref_metadata_2025 huggingface dataset:
Kadsufolins A – D and Related Cytotoxic Lignans from Kadsura oblongifolia
Authors: Huang Zehao , Lu Yan , Liu Yinan , Bastow Kenneth F. , Lee Kuohsiung , Chen Daofeng
Published: March 2011

Kadsufolins A–D (1–4, resp.), four new dibenzocyclooctane‐type lignans, were isolated from the roots and stems of Kadsura oblongifolia, together with eleven known lignans. Their structures and configurations were elucidated by spectroscopic methods including 2D‐NMR techniques. The compounds were also evaluated for cytotoxic activity against human tumor cell lines A549 (lung carcinoma), DU145 (prostate carcinoma), KB (epidermoid carcinoma of the nasopharynx), and HCT‐8 (ileocecal carcinoma). Kadsufolin A (1), kadsufolin D (4), angeloylbinankadsurin A, and heteroclitin B were found to show cytotoxic activities against A549, DU145, KB and HCT‐8 with GI50 values of 5.1–20.0 μg/ml.
One‐Pot Synthesis of Pyrimidines via Cyclocondensation of β‐Bromovinyl Aldehydes with Amidine Hydrochlorides
Authors: Yan Shengjiao , Tang Yajuan , Yu Fuchao , Lin Jun
Published: March 2011

A series of pyrimidines were prepared by cyclocondensation of β‐bromovinyl aldehydes with amidine hydrochlorides in the presence of Et3N in excellent yields (74–95%).
Note: Helix or No Helix of β‐Peptides Containing β3hAla(αF) Residues?
Authors: Jaun Bernhard , Seebach Dieter , Mathad Raveendra I.
Published: March 2011

A remote 4J(F,H) coupling (FC(α)C(O)NH) of up to 4.2 Hz in α‐fluoro amides with antiperiplanar arrangement of the CF and the CO bonds (dihedral angle FCCO ca. 180°) confirms that previous NMR determinations, using the XPLOR‐NIH procedure, of the secondary structures of β‐peptides containing β3hAla(αF) and β3hAla(αF2) residues were correct. In contrast, molecular‐dynamics (MD) simulations, using the GROMOS program with the 45A3 force field, led to an incorrect conclusion about the relative stability of secondary structures of these β‐peptides. The problems encountered in NMR analyses and computations of the structures of backbone‐F‐substituted peptides are briefly discussed.
The influence of water retention curve hysteresis on the stability of unsaturated soil slopes
Authors: Ma Kuo‐Chen , Tan Yih‐Chi , Chen Chu‐Hui
Published: March 2011

Hysteresis is a common feature exhibited in hydraulic properties of an unsaturated soil. The movement of wetting front and the hysteresis effect are important factors which impact the shear strength of the unsaturated soil and the mechanics of shallow landslides. These failures are mainly triggered by the deepening of the wetting front accompanied by a decrease in matric suction induced by infiltration. This research establishes a method for determining a stability analysis of unsaturated infinite soil slopes, integrating the influence of infiltration and the water retention curve hysteresis. Furthermore, the present stability analysis method including the infiltration model and the advanced Mohr–Coulomb failure criterion calculates the variations of the safety factor (FS) in accordance with different slope angle, depth and hydrological processes. The experimentally measured data on the effect of hysteresis are also carried out for comparison. Numerical analyses, employing both wetting and drying hydraulic behaviour of unsaturated soil, are performed to study the difference in soil‐water content as observed in the experiments. The simulating approximations also fully responded to the experimental data of sand box. The results suggest that the hysteresis behaviour affect the distribution of soil‐water content within the slope indeed. The hysteresis made the FS values a remarkable recovery during the period of non‐rainfall in a rainfall event. The appropriate hydraulic properties of soil (i.e. wetting or drying) should be used in accordance with the processes that unsaturated soil actually experience. This method will enable us to acquire more accurate matric suction head and the unsaturated soil‐shear strength as it changes with the hysteretic flow, in order to calculate into the stability analysis of shallow landslides. An advanced understanding of the process mechanism afforded by this method is critical to realizing a reliable and appropriate design for slope stabilization. It also offers some immediate reference information to the disaster reduction department of the government. Copyright © 2011 John Wiley & Sons, Ltd.
On‐demand drug delivery from self‐assembled nanofibrous gels: A new approach for treatment of proteolytic disease
Authors: Vemula Praveen Kumar , Boilard Eric , Syed Abdullah , Campbell Nathaniel R. , Muluneh Melaku , Weitz David A. , Lee David M. , Karp Jeffrey M.
Published: March 2011

Local delivery of drugs offers the potential for high local drug concentration while minimizing systemic toxicity, which is often observed with oral dosing. However, local depots are typically administered less frequently and include an initial burst followed by a continuous release. To maximize efficiency of therapy, it is critical to ensure that drug is only released when needed. One of the hallmarks of rheumatoid arthritis, for example, is its variable disease activity consisting of exacerbations of inflammation punctuated by periods of remission. This presents significant challenges for matching localized drug delivery with disease activity. An optimal system would be nontoxic and only release drugs during the period of exacerbation, self‐titrating in response to the level of inflammation. We report the development of an injectable self‐assembled nanofibrous hydrogel, from a generally recognized as safe material, which is capable of encapsulation and release of agents in response to specific enzymes that are significantly upregulated in a diseased state including matrix metalloproteinases (MMP‐2 and MMP‐9) and esterases. We show that these self‐assembled nanofibrous gels can withstand shear forces that may be experienced in dynamic environments such as joints, can remain stable following injection into healthy joints of mice, and can disassemble in vitro to release encapsulated agents in response to synovial fluid from arthritic patients. This novel approach represents a next‐generation therapeutic strategy for localized treatment of proteolytic diseases. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Dietary cadmium exposure and fracture incidence among men: A population-based prospective cohort study
Authors: Thomas Laura DK , Michaëlsson Karl , Julin Bettina , Wolk Alicja , Åkesson Agneta
Published: March 2011

Cadmium is an osteotoxic metal present in food. It causes multiple fractures in those highly exposed and is associated with reduced bone mineral density at considerably lower exposures. Little is known about fracture rates following low-level cadmium exposure. We assessed the associations between dietary cadmium exposure and fracture incidence.

Within a population-based prospective cohort of 22,173 Swedish men, we estimated individual dietary cadmium exposure using food frequency questionnaire data and levels of cadmium in food. The average intake was 19 µg/day. Hazard ratios (HRs) for any fracture and hip fracture were estimated using Cox's regression. During 10 years of follow-up, we ascertained 2183 cases of any fracture and 374 hip fractures by computerized linkage of the cohort to registry data. Multivariable-adjusted dietary cadmium intake was associated with a statistically significant 19% [HR = 1.19, 95% confidence interval (CI) 1.06–1.34] higher rate of any fracture comparing highest tertile with lowest (p ≤ .01 for trend). Moreover, men in the highest tertile of dietary cadmium and lowest tertile of fruit and vegetable consumption had a 41% higher rate of any fracture compared with contrasting tertiles. Hip fracture rates also were higher in the highest tertile of cadmium intake but only statistically significant among never smokers (HR = 1.70, 95% CI 1.04–2.77). Our results indicate that dietary cadmium exposure at general population levels is associated with an increased rate of fractures among men. This association was independent of smoking and was most pronounced among men with low fruit and vegetable consumption. © 2011 American Society for Bone and Mineral Research.
Novel optical techniques for measurements of light extinction, scattering and absorption by single aerosol particles
Authors: Miles R.E.H. , Carruthers A.E. , Reid J.P.
Published: March 2011

Aerosol particles play important roles in a broad range of scientific disciplines, from atmospheric chemistry and physics, to the delivery of fuels for combustion and drugs to the lungs, and extending to industrial processes such as spray drying. Measurements of the light extinction, scattering and absorption by ensembles of aerosol particles can be used to non‐intrusively characterise aerosol particle samples. However, such measurements often lead to ambiguity in interpreting the properties and processes occurring on individual particles. In this review, recent developments in the use of laser based techniques to isolate and manipulate single particles and to characterise them will be highlighted. In particular, the use of cavity ring down spectroscopy, Bessel beams and optical tweezers for investigating light extinction, scattering and absorption, respectively, will be considered. The prospects for using optical techniques to interrogate the fundamental processes occurring in aerosol at the single particle level are discussed.
Advanced interferometry, quantum optics and optomechanics in gravitational wave detectors
Authors: McClelland D.E. , Mavalvala N. , Chen Y. , Schnabel R.
Published: March 2011

Currently operating laser interferometric gravitational wave detectors are limited by quantum noise above a few hundred Hertz. Detectors that will come on line in the next decade are predicted to be limited by quantum noise over their entire useful frequency band (from 10 Hz to 10 kHz). Further sensitivity improvements will, therefore, rely on using quantum optical techniques such as squeezed state injection and quantum non‐demolition, which will, in turn, drive these massive mechanical systems into quantum states. This article reviews the principles behind these optical and quantum optical techniques and progress toward there realization.
The Schur multiplicative and harmonic convexities of the complete symmetric function
Authors: Chu Y.‐M. , Wang G.‐D. , Zhang X.‐H.
Published: March 2011

This paper investigates the Schur multiplicative and harmonic convexities of the complete symmetric function \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$F_n(x,r)=\sum _{i_1+i_2+\cdots +i_n=r}x_1^{i_1}x_2^{i_2}\ldots x_n^{i_n}$\end{document} and the function \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\varphi _n(x,r)=\frac{F_n(x,r)}{F_n(x,r-1)}$\end{document}, where i1, i2, …, in are nonnegative integers and r ⩾ 1. As applications, some analytic inequalities are established by use of the theory of majorization. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Limit point, strong limit point and Dirichlet conditions for Hamiltonian differential systems
Authors: Qi Jiangang , Wu Hongyou
Published: March 2011

This paper deals with singular Hamiltonian differential systems. Three conditions on the asymptotic behavior or square integrability of their maximal domain functions at a singular end point are studied: the limit point condition, the strong limit point condition and the Dirichlet condition. The equivalence between the limit point and strong limit point conditions is established for a class of such systems, and for another class, the three conditions are shown to imply each other. As an application, two unified descriptions of the Friedrichs extension for some systems in the second class are obtained. A key feature of the descriptions is: they do not use the deficiency indices of the systems. Several illustrating examples are presented. In particular, two simple descriptions of the Friedrichs extension for a family of Schrödinger operators with singular potentials are achieved. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Traces of Besov and Triebel‐Lizorkin spaces on domains
Authors: Schneider Cornelia
Published: March 2011

We determine the trace of Besov spaces \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\mathfrak {B}^s_{p,q}(\Omega )$\end{document} and Triebel‐Lizorkin spaces \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$\mathfrak {F}^s_{p,q}(\Omega )$\end{document}, characterized via atomic decompositions, on the boundary of Ck domains Ω for parameters 0 < p, q ⩽ ∞ and \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s>\frac{1}{p}$\end{document}. The limiting case \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s=\frac{1}{p}$\end{document} is investigated as well. In terms of Besov spaces our results remain valid for the classical spaces Bsp,q(Ω) defined via differences. Furthermore, we include some density assertions, which imply that the trace does not exist when \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$s<\frac{1}{p}$\end{document}. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Conformational and configurational analysis of an N,N carbonyl dipyrrinone‐derived oximate and nitrone by NMR and quantum chemical calculations
Authors: Walton Ian , Davis Marauo , Yang Liu , Zhang Yong , Tillman Destin , Jarrett William L. , Huggins Michael T. , Wallace Karl J.
Published: March 2011

The geometries and relative energies of new N,N carbonyl dipyrrinone‐derived oxime molecules (E/Z‐s‐cis 4a and E/Z‐s‐cis 4b) have been investigated. The calculated energies, molecular geometries, and 1H/13C NMR chemical shifts agree with experimental data, and the results are presented herein. The E‐s‐cis conformations of 4a and 4b and the Z‐s‐cis conformation of 5b were found to be the thermodynamically most stable isomers with the oxime hydrogen atom or the methyl functional group adopting an anti‐orientation with respect to the dipyrrinone group. This conformation was unambiguously supported by a number of 2D NMR experiments. Copyright © 2011 John Wiley & Sons, Ltd.
Magnetic poly(lactide‐co‐glycolide) and cellulose particles for MRI‐based cell tracking
Authors: Nkansah Michael K. , Thakral Durga , Shapiro Erik M.
Published: March 2011

Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide‐co‐glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil‐in‐water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r values per millimole of iron (399 sec−1 mM−1 for cellulose and 505 sec−1 mM−1 for PLGA), micron‐sized PLGA particles had a much higher r per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA‐based particles) or long‐term (cellulose‐based particles) experiments. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Fatigue leads to gait changes in spinal muscular atrophy
Authors: Montes Jacqueline , Dunaway Sally , Montgomery Megan J. , Sproule Douglas , Kaufmann Petra , De Vivo Darryl C. , Rao Ashwini K.
Published: March 2011

Introduction: Impaired mobility and fatigue are common in ambulatory spinal muscular atrophy (SMA) patients. The 6‐minute walk test (6MWT) is a reliable measure of fatigue in SMA patients. To further evaluate fatigue, we used quantitative gait analysis during the 6MWT. Methods: Nine subjects with SMA and 9 age‐ and gender‐matched, healthy controls were evaluated. Gait parameters of speed and dynamic balance were correlated with 6MWT distance. Performance during the first and last 25 meters of the 6MWT was compared. Results: Speed‐related gait parameters and support base correlated with 6MWT distance. Walking performance was worse for SMA patients. The deterioration in stride length during the 6MWT was greater in SMA patients than in controls. Conclusions: Gait analysis detects fatigue, and the decrement in stride length may reflect selective muscle involvement in SMA. Further understanding of the mechanisms underlying fatigue may suggest additional targets for future therapeutic interventions. Muscle Nerve, 2010
Rippling is not always electrically silent in rippling muscle disease
Authors: Maki Takakuni , Matsumoto Riki , Kohara Nobuo , Kondo Takayuki , Son Insuk , Mezaki Takahiro , Nishino Ichizo , Ikeda Akio , Takahashi Ryosuke
Published: March 2011

Rippling muscle disease (RMD) is a myopathy with hyperirritability, the pathophysiology for which is uncertain.We report electromyographic findings in a 30‐year‐old man with RMD. Clinical features included muscle rippling and percussion‐induced rapid muscle contractions. Both were associated with bursts of short‐duration, low‐amplitude spikes, which resembled single muscle fiber discharges. Our case stands in contrast to previously reported cases, which showed either electrical silence or motor unit potential discharges associated with rippling, and may represent muscle fiber hyperexcitability. Muscle Nerve 43: 601–605, 2011
Exercise and duchenne muscular dystrophy: Toward evidence‐based exercise prescription
Authors: Markert Chad D. , Ambrosio Fabrisia , Call Jarrod A. , Grange Robert W.
Published: March 2011

To develop a rational framework for answering questions about the role of exercise in Duchenne muscular dystrophy (DMD), we focused on five pathophysiological mechanisms and offer brief hypotheses regarding how exercise may beneficially modulate pertinent cellular and molecular pathways. We aimed to provide an integrative overview of mechanisms of DMD pathology that may improve or worsen as a result of exercise. We also sought to stimulate discussion of what outcomes/dependent variables most appropriately measure these mechanisms, with the purpose of defining criteria for well‐designed, controlled studies of exercise in DMD. The five mechanisms include pathways that are both intrinsic and extrinsic to the diseased muscle cells. Muscle Nerve 43: 464–478, 2011
Idiopathic Parkinson's disease patients at the urologic clinic
Authors: Ragab Maged M. , Mohammed Ehab S.
Published: March 2011

Aims

To quantitatively evaluate the urinary symptoms at different stages of idiopathic Parkinson's disease (IPD) severity and its relation to urodynamic parameters.

Methods

This study was conducted on 49 patients with probable IPD to quantitatively evaluate their urinary symptoms using International Prostate Symptom Score and urodynamic tests. Four, 10, 29, 5, and 1 cases were classified as stages 1–5, respectively, according to Hoehn and Yahr staging of IPD severity.

Results

The most prevailing urinary symptom in IPD was nocturia (77.5%) followed by urgency (36.7%) and frequency (32.6%). Urodynamic tests revealed neurogenic detrusor overactivity in 33 patients (67.3%), detrusor underactivity in 6 patients (12.2%), and 10 (20.4%) patients with normal detrusor function. Irritative symptom index score correlated significantly with disease severity as well as the volume at initial desire to void and maximum bladder capacity meanwhile obstructive symptom index score had no significant correlation with any of the urodynamic parameters or disease severity. Total IPSS symptoms score significantly correlated with quality of life score. The mean of urodynamic parameters did not differ in IPD patients who did or did not receive anticholinergic or dopaminergic drugs.

Conclusion

The irritative urinary symptoms manifested urodynamically as neurogenic detrusor overactivity are more common in IPD patients than obstructive symptoms. These irritative symptoms deteriorate progressively with the disease severity and significantly affect the quality of life of these patients. The International Prostate Symptom Score is a valuable tool in evaluating the urinary dysfunction in such patients. Neurourol. Urodynam. 30:1258–1261, 2011. © 2011 Wiley‐Liss, Inc.
Can the outcome of autoaugmentation omentocystoplasty be improved? urodynamic, histological, and collagen content evaluation in sheep model
Authors: Burgu Berk , Keskin Selcuk , Orhan Diclehan , Ozgencil Eser , Senel Oytun , Aydogdu Ozgu , Dogan Hasan Serkan , Tekgul Serdar
Published: March 2011

Aim

To compare histological and urodynamic outcome of the classical detrusorotomy with and without the aid of intravesical balloon distension. We also describe a new technique with multiple detrusor incisions instead of detrusorotomy.

Methods

A total of 24 animals were included in the study. Three different techniques of autoaugmentation cystoplasty were applied to surgically reduced bladders of 14 sheep. Five sheep underwent surgical reduction of bladder capacity as control group and five sheep underwent sham operation. In Group DIB (detrusor incision with balloon), standard whole thickness incisions on bladder wall were performed and a silicon balloon was inflated intravesically postoperatively. Group DMB (detrusorotomy with balloon) and Group DM (detrusorotomy) underwent standard detrusorotomy. After measuring capacities and compliances, animals were sacrificed on 90th postoperative day. Bladders were histopathologically evaluated. Expression of vascular endothelial growth factor (VEGF), CD31, and microvessel density (MVD) was noted. Quantification of collagen subtypes was also performed.

Results

The mean capacity and compliance for Group DM and control were not significantly different and both were lower than other augmentation groups and sham. In Groups DMB and DM fibrosis was significantly increased. The VEGF expression was lower in Group DIB with respect to other augmentation groups whereas MVD was not significantly different. Measurement of total collagen and collagen subtypes revealed an increase in total collagen of groups DMB and DM when compared to other groups. Quantification of collagen subtypes demonstrated that types I and III were significantly increased in aforementioned groups.

Conclusion

Autoaugmentation omentocystoplasty in sheep model does not result in a reliable increase in bladder capacity and compliance. Intravesical balloon inflation makes the achievement more pronounced and significantly increases the bladder capacity and compliance. Neurourol. Urodynam. 30:1371–1375, 2011. © 2011 Wiley‐Liss, Inc.
Cultural Modification of the Dentition in Prehistoric Cambodia
Authors: Domett K. M. , Newton J. , O'Reilly D. J. W. , Tayles N. , Shewan L. , Beavan N.
Published: March 2011

Intentional dental modification, in the form of ablation and filing, is reported for the first time from Cambodia in two late prehistoric sites (Phum Snay and Phum Sophy, c. 2500 to 1500 bp). Bioarchaeological research is relatively new for this region, and this study significantly adds to our reconstruction of past behaviours in mainland Southeast Asia. The skeletal samples combine both excavated material and large looted collections in the form of ossuaries. People from Phum Sophy and Phum Snay had similar rates of anterior maxillary dental ablation, 60 and 47%, respectively, and 21.4 and 7.7%, respectively, in the mandible. Patterns of ablation most commonly involve the removal of the maxillary lateral incisors. Intentional filing was less common than ablation but affected Phum Snay and Phum Sophy individuals to a similar level (4–7%). Filing was also restricted to the anterior dentition, and a range of patterns were evident, many involving filing of the mesial and distal aspects of the crown of the upper and lower incisors and canines to give a pointed appearance. Patterns of ablation or filing were not strongly associated with a particular sex or age group. However, a limited number of ablation and filing patterns were exclusive to each site. The significance of this practice in relation to rites of passage, status, community and family relationships, and trauma is discussed. It is also shown that the modifications show distinct differences in prevalence and pattern, particularly that of filing, to nearby temporal neighbours in southern Cambodia and northeast Thailand, suggesting a unique cultural behaviour for this region. Copyright © 2011 John Wiley & Sons, Ltd.
Notch3 signalling promotes tumour growth in colorectal cancer
Authors: Serafin Valentina , Persano Luca , Moserle Lidia , Esposito Giovanni , Ghisi Margherita , Curtarello Matteo , Bonanno Laura , Masiero Massimo , Ribatti Domenico , Stürzl Michael , Naschberger Elisabeth , Croner Roland S , Jubb Adrian M , Harris Adrian L , Koeppen Hartmut , Amadori Alberto , Indraccolo Stefano
Published: March 2011

Increased Notch1 activity has been observed in intestinal tumours, partially accomplished by β‐catenin‐mediated up‐regulation of the Notch ligand Jagged‐1. Whether further mechanisms of Notch activation exist and other Notch receptors might be involved is unclear. Microarray data indicated that Notch3 transcript levels are significantly up‐regulated in primary and metastatic CRC samples compared to normal mucosa. Moreover, Notch3 protein was expressed at strong/moderate levels by 19.7% of 158 CRC samples analysed, and at weak levels by 51.2% of the samples. Intrigued by these findings, we sought to investigate whether Notch3 modulates oncogenic features of CRC cells. By exploiting xenografts of CRC cells with different tumourigenic properties in mice, we found that the aggressive phenotype was associated with altered expression of components of the Notch pathway, including Notch3, Delta‐like 4 (DLL4), and Jagged‐1 ligands. Stimulation with immobilized recombinant DLL4 or transduction with DLL4‐expressing vectors dramatically increased Notch3 expression in CRC cells, associated with accelerated tumour growth. Forced expression of an active form of Notch3 mirrored the effects of DLL4 stimulation and increased tumour formation. Conversely, attenuation of Notch3 levels by shRNA resulted in perturbation of the cell cycle followed by reduction in cell proliferation, clonogenic capacity, and inhibition of tumour growth. Altogether, these findings indicate that Notch3 can modulate the tumourigenic properties of CRC cells and contributes to sustained Notch activity in DLL4‐expressing tumours. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Mass spectrometric analysis of GABAA receptor subtypes and phosphorylations from mouse hippocampus
Authors: Kang Sung Ung , Heo Seok , Lubec Gert
Published: March 2011

The brain GABAA receptor (GABAAR) is a key element of signaling and neural transmission in health and disease. Recently, complete sequence analysis of the recombinant GABAAR has been reported, separation and mass spectrometrical (MS) characterisation from tissue, however, has not been published so far. Hippocampi were homogenised, put on a sucrose gradient 10–69% and the layer from 10 to 20% was used for extraction of membrane proteins by a solution of Triton X‐100, 1.5 M aminocaproic acid in the presence of 0.3 M Bis‐Tris. This mixture was subsequently loaded onto blue native PAGE (BN‐PAGE) with subsequent analysis on denaturing gel systems. Spots from the 3‐DE electrophoretic run were stained with Colloidal Coomassie Brilliant Blue, and spots with an apparent molecular weight between 40 and 60 kDa were picked and in‐gel digested with trypsin, chymotrypsin and subtilisin. The resulting peptides were analysed by nano‐LC‐ESI‐MS/MS (ion trap) and protein identification was carried out using MASCOT searches. In addition, known GABAAR‐specific MS information taken from own previous studies was used for searches of GABAAR subunits. β‐1, β‐2 and β‐3, θ and ρ‐1 subunits were detected and six novel phosphorylation sites were observed and verified by phosphatase treatment. The method used herein enables identification of several GABAAR subunits from mouse hippocampus along with phosphorylations of β‐1 (T227, Y230), β‐2 (Y215, T439) and β‐3 (T282, S406) subunits. The procedure forms the basis for GABAAR studies at the protein chemical rather than at the immunochemical level in health and disease.
Bacterial adaptation to life in association with plants – A proteomic perspective from culture to in situ conditions
Authors: Knief Claudia , Delmotte Nathanaël , Vorholt Julia A.
Published: March 2011

Diverse bacterial taxa that live in association with plants affect plant health and development. This is most evident for those bacteria that undergo a symbiotic association with plants or infect the plants as pathogens. Proteome analyses have contributed significantly toward a deeper understanding of the molecular mechanisms underlying the development of these associations. They were applied to obtain a general overview of the protein composition of these bacteria, but more so to study effects of plant signaling molecules on the cytosolic proteome composition or metabolic adaptations upon plant colonization. Proteomic analyses are particularly useful for the identification of secreted proteins, which are indispensable to manipulate a host plant. Recent advances in the field of proteome analyses have initiated a new research area, the analysis of more complex microbial communities. Such studies are just at their beginning but hold great potential for the future to elucidate not only the interactions between bacteria and their host plants, but also of bacteria–bacteria interactions between different bacterial taxa when living in association with plants. These include not only the symbiotic and pathogenic bacteria, but also the commensal bacteria that are consistently found in association with plants and whose functions remain currently largely uncovered.
An introduction to counting orbifolds
Authors: Davey J. , Hanany A. , Seong R.‐K.
Published: March 2011

We review three methods of counting abelian orbifolds of the form ℂ3/Γ which are toric Calabi‐Yau (CY). The methods include the use of 3‐tuples to define the action of Γ on ℂ3, the counting of triangular toric diagrams and the construction of hexagonal brane tilings. A formula for the partition function that counts these orbifolds is given. Extensions to higher dimensional orbifolds are briefly discussed.
Pyroelectric performances of relaxor‐based ferroelectric single crystals and related infrared detectors
Authors: Zhao Xiangyong , Wu Xiao , Liu Linhua , Luo Haosu , Neumann Norbert , Yu Ping
Published: March 2011

We report in this paper our discovery of remarkably excellent pyroelectric performances in the widely investigated, but still not well understood, relaxor‐based ferroelectric single‐crystalline materials of the solid solution system of Pb(B1, B2)O3 (B1: Mg2+, In3+…, B2: Nb5+, Ta5+…) and PbTiO3, which have already been considered as next‐generation piezoelectric materials with superhigh piezoelectric effect. Values of pyroelectric coefficient as high as 17.2 × 10−4 C/m2 K and of figure of merit for detectivity of 40.2 × 10−5 Pa−1/2 can be produced in the poled crystals specifically in the crystallographic direction along the spontaneous polarization, i.e., the <111> direction in the rhombohedral phase. They show great potential as novel pyroelectric materials for wide applications in infrared (IR) detectors and thermal imagers. Commercialized IR detector prototypes have also been fabricated with the specific detectivity of 1.07 × 109 cm Hz1/2 W−1, which nearly doubles that of conventional LiTaO3 single‐crystal‐based commercialized IR detectors with similar detection mode. The relations among crystal composition, iron doping, orientation, phase structure, domain configuration, and pyroelectric property, as well as between thermal parameters and dielectric properties will also be presented here. They address the physics behind and the IR‐sensor application using the strong pyroelectric effect of this complicated but promising family of pyroelectric materials. Examples are given for Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMNT) and ternary Pb(In1/2Nb1/2)O3‐Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PIMNT) systems.
Preparation of plate‐like potassium sodium niobate particles by hydrothermal method
Authors: Zhang Fan , Bai Shan , Karaki Tomoaki
Published: March 2011

Potassium sodium niobate (K,Na)NbO3 (KNN) particles with a plate‐like morphology were prepared. First, an unknown potassium sodium niobate hydrate particles with 150‐nm thickness and 1500‐nm width were synthesised by a hydrothermal method. After calcining these particles at 450 °C, plate‐like KNN particles were obtained, which were expected to be used as templates for KNN textured ceramics. It was found that sodium dodecyl‐benzene‐sulfonate (SDBS) acting as surfactant played an important role in controlling the morphology of the particles in the hydrothermal process. The SDBS surfactant‐assisted hydrothermal synthesis is feasible for the mass production of plate‐like alkaline niobate template particles.

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Oxalate precursor route for preparing (Bi,Na)0.83Ba0.17TiO3 nanopowder and ceramics
Authors: Lv Junhua , Karaki Tomoaki , Adachi Masatoshi
Published: March 2011

An oxalate precursor route was used to synthesize (Bi,Na)0.83Ba0.17TiO3 nanopowders. Perovskite phases developed at 750 °C, and the particles were uniform and well dispersed with a diameter smaller than 100 nm. Using such powders, a dense ceramics with a particular subgrain microstructure was sintered at the low temperature of 1120 °C. This ceramics exhibits excellent electrical properties: the electromechanical coupling factor kp is 18.3%, the dielectric loss tanδ is 2.23%, the depolarization temperature Td is 235 °C, and the temperature corresponding to the maximum value of the dielectric constant Tm is 249 °C. Furthermore, the temperature range of the anti‐ferroelectric state decreased.
Electrical characteristics and interfacial reactions of rapidly annealed Pt/Ru Schottky contacts on n‐type GaN
Authors: Reddy N. Nanda Kumar , Reddy V. Rajagopal , Choi C.‐J.
Published: March 2011

The electrical properties and interfacial reactions of Pt/Ru Schottky contacts on n‐type gallium nitride (GaN) have been investigated as a function of annealing temperature. The calculated Schottky barrier height (SBH) of the as‐deposited Pt/Ru Schottky contact is found to be 0.69 eV current–voltage (I–V) and 0.76 eV capacitance–voltage (C–V). Experimental results showed that the SBHs are increased on increasing the annealing temperature. When the contact is annealed at 600 °C, a maximum barrier height is obtained and the corresponding values are 0.87 eV (I–V) and 0.99 eV (C–V). The Norde method was also employed to extract the barrier height of Pt/Ru Schottky contacts and the values are 0.70 and 0.86 eV for the samples as‐deposited and annealed at 600 °C, which are in good agreement with those obtained from the I–V measurement. Shifts of the surface Fermi level are measured with the change in position of the Ga 2p core level peak. Based on the X‐ray photoelectron spectroscopy (XPS) and X‐ray diffraction (XRD) studies, the formation of gallide phases at the Ru/Pt/n‐GaN interface could be the reason for the increase in SBH at elevated temperatures. Atomic force microscopy (AFM) results showed that the surface morphology of the Pt/Ru Schottky contact did not change significantly even after annealing at 600 °C. These results point out that a Pt/Ru Schottky contact may be a suitable candidate for the fabrication of GaN‐based high‐temperature device applications.
Investigation of the electric properties of Cu2S single crystals
Authors: Abdullaev G. B. , Aliyarova Z. A. , Zamanova E. H. , Asadov G. A.
Published: March 2011

Single crystals of p‐Cu2S are obtained with a hole concentration of 7.4 × 1019 cm−3, a mobility of 25 cm2 V−1 S−1, and a thermoelectric power of 90 mV/deg. The electrical conductivity, thermoelectric power and Hall effect are measured between 20 and 600°C. A jump due to structural transformations is observed in the temperature dependence of these parameters at 125 and 480°C. The activation energy is found to have a value of 1.8 eV for the intrinsic range of the conductivity, the value found for the extrinsic range being 0.064 eV.
High‐temperature modifications of the semiconductor compounds CdSnAs2 and CdGeAs2
Authors: Osmanov E. O. , Rud Yu. V. , Stryalkovskii M. E.
Published: March 2011

The results are considered of a comparative investigation of the properties of CdSnAs2 and CdGeAs2 compounds with the usual chalkopyrite‐type structure and with their high temperature modifications. Results are given for the changes which occur in the microhardness, electrical properties, and thermal conductivity as a result of the phase changes. It is found that the electron mobility in CdSnAs2 with the sphalerite‐type structure is less than half that of crystals with the usual structure. The thermal conductivity of vitreous CdGeAs2 (5.5 × 10−3 W/cm.deg) is about an order less than for a single crystal (68.6x × 10−3 W/cm.deg).
Exchange and spin‐orbit coupling in KFeF3
Authors: Fatehally R. , Sastry N. P. , Nagarajan R.
Published: March 2011

KFeF3, with perovskite structure. is known to be antiferromagnetic below TN = 115°K. The ferrous ion has some unquenched angular momentum, which plays an important role in magnetic ordering. Using a single ion Hamiltonian which includes spin‐orbit and exchange contributions, it is shown that the sublattice magnetization can only be stabilized in one of two possible directions. The Hamiltonian is treated in a self‐consistent way, and shown to be consistent with Mössbauer spectra below TN, and a value of the exchange constant J is obtained. A consideration of this and previous estimates leads to J/k ≈︁ 7°k.
Minority carriers in zinc sulphide
Authors: Friedrich H. , Sysoev L. A. , Thiessen K.
Published: March 2011

Photovoltage and photoconductivity measurements were made in non‐intentionally doped and Cu diffusion‐doped ZnS crystals grown from melt. under high pressure. The photovoltage measurements allow the excitation of minority carriers to be detected. Whereas in the non‐intentionally doped samples minority carriers are generated only by irradiation in the fundamental lattice absorption range, in Cu‐doped crystals an excitation of holes is observed down to 2.5 eV. The hole lifetimes at fundamental lattice excitation have values of 10−10 to 10−12 s in Cu‐doped samples, in the undoped samples they are greater than 10−10 s. The photovoltage spectra are similar to the excitation spectra of photoluminescence.
Hot electron mobility in polar semiconductors
Authors: Licea I.
Published: March 2011

The mobility of “warm” and “hot” electrons in polar semiconductors with a non‐parabolic energy band ns that of n‐type InSb is studied theoretically by means of energy and momentum conservation equations. The calculations are carried out assuming only optical polar scattering for the case that the energy and momentum exchange is controlled by interelectronic collisions. A comparison with the parabolic case and a discussion on the validity of the model are made. The accounting of non‐parabolicity for hot electrons implies that the breakdown is not predicted.
Electrical conductivity of metals
Authors: Kishore R.
Published: March 2011

With the help of Kubo formula an expression for the electrical conductivity of metals is obtained within the Hartree‐Fock approximation using the method of double time temperature dependent Green's function. A simple calculation of the relevant relaxation time appearing in the expression is presented. This gives a reasonably good estimate of the electrical conductivity of metals.
Relativistic KKR‐calculations on the band structure of selenium and tellurium
Authors: Kramer B. , Thomas P.
Published: March 2011

The influence of relativistic corrections and spin‐orbit coupling in the band structure of selenium and tellurium is calculated using the relativistic Korringa‐Kohn‐Rostokermethod. The symmetrized central‐field spinors are given. The 11 μm‐band of tellurium is explained by spin‐orbit splitting at the upper valence band edge at H.
Climb of extrinsic faults in silicon
Authors: Dash S. , Joshi M. L.
Published: March 2011

Frank hexagonal loops, extrinsic stacking faults, and misfit dislocations can be generated through diffusion of very high concentrations of As in silicon. If a thin film of silicon containing such extrinsic faults and dislocations is quenched, the quenched‐in vacancies annihilate the stacking faults at the locations where dislocations approach the faults. This paper discusses the probable mechanism of such fault annihilation.
On the effective recombination cross‐section of charged centres in crystal phosphors
Authors: Antonov‐Romanovskii V. V.
Published: March 2011

The effective recombination cross‐section σeff of charged centres measured experimentally is found to be not always equal to the gas kinetical cross‐section σk. σeff is also dependent on the diffusion coefficient D and mobility μ. Such a dependence is enhanced at small free pass length l. In a general case the relation holds σk≦ σeff≦ σμ MD (where σμ is the pure drift cross‐section and MD is multiplication constant due to diffusion; σμ = (4 π R′l)/3, where R′ is the distance at which the potential energy of the free charge in the field of the centre becomes equal to kT). At small σk a temperature dependence can arise with “negative” activation energy σeff ∼ e−E/kT, where E < 0. The limiting case σeff = σk is not trivial because the equality is due to original mutual compensation of drift and diffusion.
Direct observations of plane wave and spherical wave Pendellösung fringes
Authors: Hart M. , Milne A. D.
Published: March 2011

By using successive Bragg reflections in a monolithic block of effectively perfect silicon, both plane wave (Ewald type) and spherical wave (Kato type) Pendellösung fringes have been obtained in the same wedge‐shaped crystal. In agreement with the theories, the fringe spacings are the same only at the centre of Bragg reflection and the fringe positions are different in the two cases.
Thermally activated dislocation motion in a solid containing a multiple spectrum of dislocation obstacles
Authors: Frank W.
Published: March 2011

A theoretical treatment is given of the thermally activated motion of dislocations in the presence of dislocation obstacles with different hardness. The hardness of an obstacle is allowed to depend on an arbitrary number of characteristic parameters (multiple obstacle spectrum). It is shown that even under these conditions the slip rate ȧ obeys an Arrhenius equation mean free activation enthalpy. The general theory is applied to the case of plastic flow in neutron‐irradiated copper. In this case the dislocation obstacles are vacancy dislocation loops of different sizes, different orientations, and different distances from the slip planes of the mobile dislocations (triple spectrum).
N‐ and S‐type negative resistances and relaxation oscillations in Au‐doped double injection Ge diodes
Authors: Hennig H.‐P.
Published: March 2011

In the course of investigations of Au‐doped double injection Ge diodes with a 0.15 eV level partially populated at thermal equilibrium, a voltage‐controlled negative resistance was observed below 65°K before the current‐controlled S‐type negative resistance occurring with DI diodes becomes important. The creation of N‐type negative resistance can be explained by an occupation of the 0.2 eV gold level, while the generation of oscillations must be related to the creation of the S‐type negative resistance [5].
Mössbauer spectrum shift depending on the degree of spin‐system ordering
Authors: Bashkirov Sh. Sh. , Selyutin G. Ya.
Published: March 2011

A theoretical investigation is made of the Mössbauer shift in crystals containing exchange coupled magnetic ions. It is found that the shift is caused by the exchange interaction and depends on the degree of ordering of the spin system.
Charge compensation of trapped holes in silver bromide
Authors: Buroff A. , Malinowski J.
Published: March 2011

The temperature dependence of the hole photoresponse in silver bromide single crystals is measured in the temperature range 200 to 300°K. The bulk lifetime of photoexcited holes is shown to pass through a minimum at temperatures where the drift mobility exhibits a maximum value. The analysis of the experimental results suggests that the lifetime of holes is limited by a neutralization process, presumably by silver ion vacancies, preceded by multiple trapping at a level 0.41 eV above the valence band. The proposed scheme is in accordance with other experimental results concerning the properties of holes in silver bromides.
Optical study on the ferroelectric orthorhombic phase of Fe‐I‐boracite
Authors: Kobayashi J. , Schmid H. , Ascher E.
Published: March 2011

The ferro‐electricity of the Fe‐I‐boracite is confirmed by the direct observation of domain‐switching. By using this phenomenon, the birefringence in the three principal sections of the indicatrix is measured as a function of temperature. The abrupt and large change of the electrostrictive nature along the ferroelectric axis at the ferro‐electric transformation is demonstrated.
On the trap distribution in thin films of copper phthalocyanine
Authors: Hamann C.
Published: March 2011

Thin films of copper phthalocyanine are found to be intrinsic semiconductors with an energy gap of 1.98 eV. Their electric properties at high fields are determined by an exponential trap distribution. The form of the distribution and its parameters are determined by SCLC‐measurements, the discret character of the trap level spectrum by back current measurements. All results may be interpreted by assuming a model of an isotropic nondegenerate semiconductor whose effective hole mobility is higher than the effective electron mobility.
Spin density oscillations in a polarized free electron gas
Authors: de Chatel P. , Szabó I.
Published: March 2011

The wave‐number dependent dynamic susceptibility of a uniformly polarized free electron gas is calculated. Due to the polarization the spin density oscillations around a sharply localized magnetic impurity are modified both in phase and amplitude. The oscillations in the totally magnetized state are enhanced by about 20 percent, but in intermediate states they are smaller than in the unmagnetized system.
A study of quench hardening in copper
Authors: Davidson J. L. , Galligan J. M.
Published: March 2011

Quenching studies of copper, under clean conditions, have revealed a two stage hardening mechanism. The first stage corresponds to the formation of small vacancy clusters and occurs around room temperature, while the second stage is centered around 250°C. Measurements of the dislocation loop density in quenched, aged specimens in the second stage of hardening, show that Frank vacancy loops are the major obstacle to dislocation motion. The temperature dependence of the critical resolved shear stress, in quenched specimens, was also measured throughout the aging process and compared with various expressions for the interaction of mobile dislocations with different obstacles. These results indicate quite clearly that Seeger's theory of obstacle shearing is favored over Fleisher's theory of asymmetrical distortion in this case. An experimental value of the cutting process is about 5 eV. In agreement with this mechanism, electron microscope observations show that Frank dislocation loops, within a slip plane, are removed during the first few percent of plastic deformation. Finally, the quench hardening is only removed at very high temperatures, in the same temperature range where the Frank loops are removed.