bluuebunny/crossref_metadata_2025 huggingface dataset:
Photophobia in essential blepharospasm—A positron emission tomographic study
Authors: Emoto Hirofumi , Suzuki Yukihisa , Wakakura Masato , Horie Chiharu , Kiyosawa Motohiro , Mochizuki Manabu , Kawasaki Keiichi , Oda Keiichi , Ishiwata Kiichi , Ishii Kenji
Published: December 2009

To localize regional alterations in cerebral glucose metabolism in essential blepharospasm (EB) patients with photophobia. We have studied 22 EB patients by performing positron emission tomography and [18F]‐fluorodeoxyglucose analysis. The patients were classified into two subgroups, namely, EB with photophobia (P group) and EB without photophobia (NP group), and compared with a healthy control group (n = 44). There were no significant differences between the two patient groups with respect to the severity of motor symptoms or the duration for which the condition persisted. The FDG‐PET images were analyzed using the statistical parametric mapping software. As compared to the control group, the P group exhibited significant hypermetabolism in the thalamus (P = 0.002), while the NP group exhibited significant hypometabolism in the dorsal midbrain, especially, in the superior colliculus (P = 0.005). The P group exhibited significant hypermetabolism in the thalamus and the dorsal midbrain as compared to the NP group (P < 0.001). These findings suggest that photophobia in EB patients may be associated with abnormal hyperactivity in the thalamus. Either hyperactivity of the thalamus or hypoactivity of the superior colliculus, or both may be associated with excessive blinking in these patients. © 2009 Movement Disorder Society
Depression and major depressive disorder in patients with Parkinson's disease
Authors: Inoue Takeshi , Kitagawa Mayumi , Tanaka Teruaki , Nakagawa Shin , Koyama Tsukasa
Published: December 2009

The prevalence of depression in Parkinson's disease (PD) varies greatly. In this study, we investigated major depressive disorder (MDD) and depressive symptoms without MDD in patients with PD. The psychopathological characteristics of depressive symptoms were assessed by a psychiatric interview. A total of 105 Japanese patients with PD without dementia were included. The Japanese version of the Beck Depression Inventory‐II (BDI‐II) with a cutoff score of 13/14 was used to screen for depression. Using a structured interview, a comprehensive psychiatric evaluation of patients with BDI‐II scores >13 (high BDI patients) was completed using the criteria of the Diagnostic and Statistical Manual of Mental Disorders (DSM)‐IV‐TR. Forty patients (38%) had a BDI‐II >13, but 29 did not show any depressed mood. Five cases met the criteria for MDD (three current, two past) and one patient was diagnosed with minor depressive disorder. A slight depressed mood that was associated with worrying about PD was seen in 6 of 34 patients without any depressive disorder and fluctuated with aggravation of PD symptoms in two of these patients. For the diagnosis of MDD, the number of positive items from the DSM‐IV‐TR definition of MDD is most important and useful for differentiating MDD and non‐MDD. The low‐prevalence rate of MDD in our patient population suggests that PD may be a psychological stressor for MDD, but does not necessarily induce MDD. © 2009 Movement Disorder Society
Steady‐state level of kit ligand mRNA in goat ovaries and the role of kit ligand in preantral follicle survival and growth in vitro
Authors: Celestino Juliana J.H. , Bruno Jamily B. , Lima‐Verde Isabel B. , Matos Maria Helena T. , Saraiva Mércia Viviane A. , Chaves Roberta N. , Martins Fabricio S. , Almeida Anderson P. , Cunha Rodrigo M.S. , Lima Laritza F. , Name Khesller P.O. , Campello Claudio C. , Silva José Roberto V. , Báo Sônia N. , Figueiredo José Ricardo
Published: December 2009

The aims of this study were to investigate steady‐state level of Kit Ligand (KL) mRNA and its effects on in vitro survival and growth of caprine preantral follicles. RT‐PCR was used to analyze caprine steady‐state level of KL mRNA in primordial, primary, and secondary follicles, and in small (1–3 mm) and large (3–6 mm) antral follicles. Furthermore, ovarian fragments were cultured for 1 or 7 days in Minimal Essential Medium (MEM+) supplemented with KL (0, 1, 10, 50, 100, or 200 ng/ml). Noncultured (control) and cultured fragments were processed for histology and transmission electron microscopy (TEM). RT‐PCR demonstrated an increase in steady‐state level of KL mRNA during the transition from primary to secondary follicles. Small antral follicles had higher steady‐state levels of KL mRNA in granulosa and theca cells than large follicles. After 7 days, only 50 ng/ml of KL had maintained the percentage of normal follicles similar to control. After 1 day, all KL concentrations reduced the percentage of primordial follicles and increased the percentage of growing follicles. KL at 10, 50, 100, or 200 ng/ml increased primary follicles, compared to MEM+ after 7 days. An increase in oocyte and follicular diameter was observed at 50 ng/ml of KL. TEM confirmed ultrastructural integrity of follicles after 7 days at 50 ng/ml of KL. In conclusion, the KL mRNAs were detected in all follicular categories. Furthermore, 50 ng/ml of KL maintained the integrity of caprine preantral follicle cultured for 7 days and stimulated primordial follicle activation and follicle growth. Mol. Reprod. Dev. 77: 231–240, 2010. © 2009 Wiley‐Liss, Inc.
Compact schemes for anisotropic reaction–diffusion equations with adaptive time step
Authors: Heidenreich E. A. , Gaspar F. J. , Ferrero J. M. , Rodríguez J. F.
Published: December 2009

Many problems in biology and engineering are governed by anisotropic reaction–diffusion equations with a very rapidly varying reaction term. These characteristics of the system imply the use of very fine meshes and small time steps in order to accurately capture the propagating wave avoiding the appearance of spurious oscillations in the wave front. This work develops a fourth‐order compact scheme for anisotropic reaction–diffusion equations with stiff reactive terms. As mentioned, the scheme accounts for the anisotropy of the media and incorporates an adaptive time step for handling the stiff reactive term. The high‐order scheme allows working with coarser meshes without compromising numerical accuracy rendering a more efficient numerical algorithm by reducing the total computation time and memory requirements. The order of convergence of the method has been demonstrated on an analytical solution with Neumann boundary conditions. The scheme has also been implemented for the solution of anisotropic electrophysiology problems. Anisotropic square samples of normal and ischemic cardiac tissue have been simulated by means of the monodomain model with the reactive term defined by Luo–Rudy II dynamics. The simulations proved the effectiveness of the method in handling anisotropic heterogeneous non‐linear reaction–diffusion problems. Bidimensional tests also indicate that the fourth‐order scheme requires meshes about 45% coarser than the standard second‐order method in order to achieve the same accuracy of the results. Copyright © 2009 John Wiley & Sons, Ltd.
Scalable TFETI algorithm for the solution of multibody contact problems of elasticity
Authors: Dostál Z. , Kozubek T. , Vondrák V. , Brzobohatý T. , Markopoulos A.
Published: December 2009

A Total FETI (TFETI)‐based domain decomposition algorithm with preconditioning by a natural coarse grid of the rigid body motions is adapted to the solution of multibody contact problems of elasticity in 2D and 3D and proved to be scalable. The algorithm finds an approximate solution at the cost asymptotically proportional to the number of variables provided the ratio of the decomposition parameter and the discretization parameter is bounded. The analysis is based on the classical results by Farhat, Mandel, and Roux on scalability of FETI with a natural coarse grid for linear problems and on our development of optimal quadratic programming algorithms for bound and equality constrained problems. The algorithm preserves parallel scalability of the classical FETI method. Both theoretical results and numerical experiments indicate a high efficiency of our algorithm. In addition, its performance is illustrated on a real‐world problem of analysis of the ball bearing. Copyright © 2009 John Wiley & Sons, Ltd.
K‐ras exon 4A has a tumour suppressor effect on carcinogen‐induced murine colonic adenoma formation
Authors: Luo Feijun , Ye Hongtao , Hamoudi Rifat , Dong Gehong , Zhang Wenyan , Patek Charles E , Poulogiannis George , Arends Mark J
Published: December 2009

K‐ras encodes two isoforms, K‐ras 4A and 4B, that are jointly affected by K‐ras activating mutations, which are prevalent in colorectal cancer (CRC). CRC shows alterations in the expressed K‐ras 4A : 4B isoform ratio in favour of K‐ras 4B, in tumours both with and without K‐ras mutations. The present study evaluated whether K‐ras 4A expression can suppress colonic adenoma development in the absence of its oncogenic allele. Mice with homozygous targeted deletions of K‐ras exon 4A (K‐rastmΔ4A/tmΔ4A) that can express the K‐ras 4B isoform only, along with heterozygous K‐rastmΔ4A/+ and wild‐type mice, were given ten weekly 1,2‐dimethylhydrazine (DMH) treatments to induce colonic adenomas. There was a significant increase in both the number and the size of colonic adenomas in DMH‐treated K‐rastmΔ4A/tmΔ4A mice, with reduced survival, compared with heterozygous and wild‐type mice. No K‐ras mutations were found in any of the 30 tumours tested from the three groups. Lack of expression of K‐ras 4A transcripts was confirmed, whereas the relative expression levels of K‐ras 4B transcripts were significantly increased in the adenomas of K‐rastmΔ4A/tmΔ4A mice compared with K‐rastmΔ4A/+ and wild‐type mice. Immunohistochemical studies showed that adenomas of K‐rastmΔ4A/tmΔ4A mice had significantly increased cell proliferation and significantly decreased apoptosis with evidence of activation of MapKinase and Akt pathways, with increased phospho‐Erk1/2 and both phospho‐Akt‐Thr308 and phospho‐Akt‐Ser473 immunostaining, compared with adenomas from K‐rastmΔ4A/+ and wild‐type mice. In conclusion, following DMH treatment, K‐ras exon 4A deletion promoted increased number and size of colonic adenomas showing increased K‐ras 4B expression, increased proliferation, decreased apoptosis, and activation of MapKinase and Akt pathways, in the absence of K‐ras mutations. Therefore, K‐ras 4A expression had a tumour suppressor effect on carcinogen‐induced murine colonic adenoma formation, explaining the selective advantage of the altered K‐ras 4A : 4B isoform ratio found in human colorectal cancer. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Efficacy of insulin lispro in pregnancies complicated with pregestational diabetes mellitus
Authors: Banerjee M , Bhattacharya A , Hughes SM , Vice PA
Published: December 2009

Insulin is the mainstay in the management of pregnancies complicated by pregestational diabetes. Insulin analogues are useful in the non‐pregnant state, leading to better glycaemic control. Our study tested the hypothesis that using insulin lispro in such pregnancies would lead to better feto‐maternal outcome when compared to human insulin.

The study was conducted as a retrospective case‐control study, and was undertaken in the antenatal clinic of Lancashire Teaching Hospitals NHS Trust between 1997 and 2001. The study involved 153 consecutive women with pregestational diabetes, 83 of whom were treated with insulin lispro and the rest with human insulin. Details of their management and outcome were derived from their medical, obstetric and paediatric notes. The main outcome measures were: maternal glycaemic control at term, conclusion of pregnancy, Caesarean section rate, birth weight, neonatal intensive care unit (NICU) admission, neonatal jaundice, congenital anomalies and neonatal hypoglycaemia.

There was a significant improvement in HbA1c at term in the group treated with insulin lispro (‐0.75%, [‐1.04 to ‐0.46]) when compared with the human insulin group (‐0.18%, [‐0.47 to 0.11]); p=0.005. This was not associated with a significant difference in feto‐maternal outcome, apart from a higher NICU admission rate in the insulin lispro group. This adverse effect disappeared after adjusting for other co‐variates.

Hence, when compared to human insulin, insulin lispro provides better glycaemic control, without adversely affecting feto‐maternal outcomes in pregnancy complicated with pregestational diabetes, which may be reflected in a better developmental outcome in the children. Copyright © 2009 John Wiley & Sons.
Use of psychotropic drugs and analgesics among users of antiobesity drugs—a population based study
Authors: Amundsen Merethe Omdal , Engdahl Bo , Berg Christian , Nordeng Hedvig
Published: December 2009

Aim

The aim of the present study was to investigate to what extent patients using prescription antiobesity drugs (orlistat, sibutramine and rimonabant) concomitantly or concurrently used psychotropic drugs and analgesics and the association between this drug use and the patients' gender and age. An additional aim was to investigate the sequence of drug therapy among users of both antiobesity drugs and antidepressants or antipsychotics, respectively.

Methods

Data were retrieved from the Norwegian Prescription Database (NorPD). All patients who had an antiobesity drug (ATC code A08A) dispensed from a Norwegian pharmacy between January 2004 and December 2007 were included in the study.

Results

One in four patients using antiobesity drugs had at least on one occasion used a psychotropic drug concomitantly. The most commonly used psychotropic drugs were anxiolytics/hypnotics/sedatives (17.7%) and antidepressants (14.7%). Analgesics were used by 36.2%. A significantly higher percentage of women used anxiolytics/hypnotics/sedatives (18.8% vs. 14.0%, p < 0.0005), antidepressants (16.1% vs. 9.5%, p < 0.0005), antipsychotics (4.0% vs. 2.9%, p < 0.0005) and analgesics (37.8% vs. 30.5%, p < 0.0005) concomitantly with antiobesity drugs when compared to men. One out of ten patients using sibutramine had at least on one occasion used an interacting drug concomitantly.

Conclusion

Use of psychotropic drugs and analgesics among patients using antiobesity drugs is extensive, especially among women. Clinicians prescribing sibutramine should be more aware of drug interactions with other prescribed drugs. There is still insufficient information on psychiatric disorders among these patients. Copyright © 2009 John Wiley & Sons, Ltd.
Enhanced wear performance of nylon 6/organoclay nanocomposite by blending with a thermotropic liquid crystalline polymer
Authors: Zhang Baoqing , Wong Julia Shuk‐Ping , Yam Richard Ching‐Man , Li Robert Kwok‐Yiu
Published: December 2009

A new approach for improving the wear performances of nylon 6 (PA6)/clay nanocomposites was examined in this study. Two hybrid nanocomposites were prepared by melt blending a thermotropic liquid crystalline polymer (TLCP) and a well‐dispersed PA6/clay nanocomposite, but with and without the incorporation of maleic‐anhydride grafted polypropylene (MAPP) as compatibilizer. The addition of MAPP improved the compatibility between TLCP and matrix and thus enhanced the fibrillation of dispersed TLCP phase. Wear‐testing results revealed that the wear resistance of the compatibilized hybrid nanocomposite could be improved effectively, as indicated by the low values of specific wear rate and frictional coefficient, especially under high‐normal load (i.e., 80 N). Based on the characterization on the worn damage and the debris, it was suggested that abrasive wear was the main‐damage mechanism for all the materials under investigation, except for the compatibilized hybrid nanocomposite. For this system, the wear damage was caused by a combination of abrasive and adhesive wearing because of the formation of transfer film on the counter pin surface from the wear debris. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Higher‐molecular‐weight hyperbranched polyethylenes containing crosslinking structures as lubricant viscosity‐index improvers
Authors: Morgan Shawn , Ye Zhibin , Subramanian Ramesh , Zhu Shiping
Published: December 2009

As a new grade of polyethylene materials with unique chain architectures, hyperbranched polyethylenes synthesized by chain walking ethylene polymerization have great potential for industrial application as novel viscosity index (VI) improver in lubricant formulation. Although high‐molecular‐weight hyperbranched polyethylenes (weight‐average molecular weight of about 105 g/mol) possess high shear stability, their viscosity thickening properties are compromised due to their compact chain architectures. In this work, we aim at improving their viscosity thickening property by increasing polymer molecular weight. A range of hyperbranched polymers of various enhanced molecular weights were synthesized by chain walking ethylene polymerization in the presence of small amounts of 1,4‐butanediol diacrylate as a difunctional crosslinker. The molecular weight dependences of viscosity thickening power and shear stability of these polymers containing crosslinking structures were evaluated. It is found that, with the increase of molecular weight via crosslinking, these polymers showed consistently enhanced viscosity thickening power, but with the reduced shear stability. However, their shear stability was still significantly better compared to linear polymers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Cyclic interaction between normal and shear stresses of an epoxy polymer—Experiments and model predictions
Authors: Xia Zihui , Shen Xinghe , Ellyin Fernand
Published: December 2009

This investigation focuses on the axial‐torsional loading interaction of an epoxy polymer, Epon 826/Epi‐Cure Curing Agent 9551. Thin‐walled tubular specimens were subjected to combined constant tensile (or shear) stress and cyclic shear (or tension) loading schemes. Pure tensile creep and shear creep tests were also performed to compare the creep deformation to that with superimposed cyclic shear or cyclic tension. Test data clearly showed that cyclic shear (or cyclic tension) have a readily discernible effect on the tensile (or shear) creep deformation. Similarly, a superimposed constant tensile (or shear) load affects the hysteresis responses in cyclic shear (or cyclic tension). A nonlinear constitutive model developed by the authors was used to simulate the observed normal‐shear stress interaction. Due to the inclusion of an effective stress parameter in its nonlinear function, this model was able to account for the normal‐shear coupling effect. However, the incorporation of a general loading/unloading rule led to inaccurate simulation of the observed oscillatory creep response. A modification of the general rule was proposed and better predictions on both the cyclic and the creep responses could be obtained. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Electrical characterization of the boron trifluoride doped poly(3‐aminoacetophenone)/p‐Si junction
Authors: Yakuphanoglu Fahrettin , Şenkal B. Filiz
Published: December 2009

Electrical and interface state properties of the borontrifluoride doped poly(3‐aminoacetophenone)/p‐Si junction have been investigated by current‐voltage and impedance spectroscopy methods. Al/p‐Si/P3APBF3/Aldiode indicates a nonideal behavior with electrical parameters (n = 3.53, ϕB = 0.82 eV, and Rs = 1.48 kΩ), which result from the interfacial layer, series resistance, and resistance of the organic semiconductor. The obtained barrier height value of the Al/p‐Si/P3APBF3/Aldiode is higher than that of the conventional Al/p‐Si (ϕB = 0.58 eV) Schottky diode. The interface state density of the diode was of the order of 1.05× 1012 eV−1 cm−2. It is evaluated that the barrier height and interface state density values of the diode are modified using the boron trifluoride doped poly (3‐aminoacetophenone) organic semiconductor. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Avoiding bias: the key to good leadership in psychiatric practice?
Authors: de Silva Prasanna
Published: December 2009

In this article, Dr de Silva argues that understanding bias and the application of appropriate safegards to avoid it mark out true professionalism and leadership within medical practice, and describes how this applies within the field of psychiatry in particular. Copyright © 2009 Wiley Interface Ltd
Management of multiple sclerosis during pregnancy
Authors: Brookings William , Lee Martin
Published: December 2009

In Pregnancy is a series of reviews focusing on the management of women with psychiatric and neurological conditions during pregnancy. In this article, Dr Brookings and Dr Lee describe how pregnancy can affect the course of multiple sclerosis (MS),discuss the safety of MS therapies and highlight other management issues to consider during pregnancy and postpartum. Copyright © 2009 Wiley Interface Ltd
Parkinson's Disease Society 6th Spring Conference for Researchers
Authors: Bedford Lynn
Published: December 2009

The Parkinson's Disease Society's 6th Spring Conference for Researchers was held in London in May, entitled ‘Parkinson's Disease:The Pieces of the Puzzle’. Here, Dr Lynn Bedford, Parkinson's Disease Society Senior Research Fellow, reports on some of the highlights of the conference, including the latest genetic research, the importance of pre‐motor symptoms and the therapeutic potential of the peptide exendin‐4, found in the saliva of a poisonous lizard. Copyright © 2009 Wiley Interface Ltd
The pharmacological management of anxiety disorders
Authors: Bleakley Stephen
Published: December 2009

Progress in Neurology and Psychiatry is running a series of articles on the major psychiatric drug groups, produced in association with the College of Mental Health Pharmacists. In this article, Stephen Bleakley provides an overview of the main types of anxiety disorder and the efficacy and side‐effects of the drugs recommended for the treatment of these disorders. Copyright © 2009 Wiley Interface Ltd
NICE focuses on depression in chronic ill health
Authors: Titmarsh Steve
Published: December 2009

Identifying and treating depression in adults with chronic physical health problems (including neurological disorders) is highlighted in a new clinical guideline from the National Institute for Health and Clinical Excellence (NICE).1 The new guideline is linked with an updated version of NICE's depression clinical guideline.2 SteveTitmarsh reports from a Press briefing held in London to announce the new guidelines. Copyright © 2009 Wiley Interface Ltd
Errors in the recognition and diagnosis of sleep disorders
Authors: Stores Gregory
Published: December 2009

The lecture ‘Sleep Disorders ‐ an Update for Psychiatrists’ was given by Professor Gregory Stores at the eighth Latest Advances in Psychiatry Symposium in London in March. Professor Stores discussed the fact that sleep disorders can often be misinterpreted as psychiatric disorders, and in this article, he provides more information on this often‐neglected topic. Copyright © 2009 Wiley Interface Ltd
Educating staff about delirium in an acute hospital setting
Authors: Law Emma , Connelly Peter , Prentice Neil , Rooke David
Published: December 2009

Delirium is often underdetected or misdiagnosed within the hospital setting. Here, the authors present the results of their study to assess whether a simple educational programme delivered to nursing staff within their District General Hospital can improve the rate of detection of delirium. Copyright © 2009 Wiley Interface Ltd
The development and impact of insomnia on cancer survivors: a qualitative analysis
Authors: Fleming Leanne , Gillespie Stephanie , Espie Colin A.
Published: December 2009

Objectives: To conduct the first qualitative analysis of the development and impact of insomnia on a cohort of cancer survivors.

Methods: Twenty‐one cancer survivors with a history of chronic insomnia contributed to four focus groups held at the University of Glasgow Sleep Research Centre. Participants' perceptions of the onset, evolution and effects of insomnia were elicited and qualitatively explored using content analysis.

Results: Most participants reported insomnia onset following cancer diagnosis. Participants who had a pre‐existing insomnia reported that cancer diagnosis significantly aggravated their sleep complaint. Active cancer treatment was a major contributor to poor sleep quality due to the disruption of normal daily routines. This poor sleep pattern became persistent once active treatment had ceased and participants reported becoming particularly concerned about their sleep when they were discharged into follow‐up cancer care. The impact of insomnia was significant for all participants in the study and six major areas emerged as being particularly affected; mood, physical health, relationships, sleep quality, sleep‐related behaviour and cognition.

Conclusions: The majority of cancer survivors in this study developed disturbed sleep as a result of cancer diagnosis and their sleep disruption was exacerbated by active cancer treatment. Insomnia also had a significant impact upon quality of life and these effects persisted long beyond the cessation of active anti‐cancer therapy. Early identification of insomnia symptoms in cancer care settings must be a priority to ensure that sleep disturbance is not overlooked or poorly managed. Copyright © 2010 John Wiley & Sons, Ltd.
Agents of support: psychometric properties of the Cancer Perceived Agents of Social Support (CPASS) questionnaire
Authors: Goldzweig Gil , Hasson‐Ohayon Ilanit , Meirovitz Amichay , Braun Michal , Hubert Ayala , Baider Lea
Published: December 2009

Objective: The current study presents the development and the evaluation of the psychometric properties of the Cancer Perceived Agents of Social Support (CPASS). The CPASS is a new self‐rating instrument devised in order to enable both cancer patients and their spouses to report on the level of perceived social support they get. The CPASS evaluates the support given by different agents of support (spouse, family, friends and spiritual or religious beliefs) in several dimensions (emotional, cognitive and instrumental).

Methods: The study sample comprised 662 cancer patients and their spouses recruited during a routine medical evaluation from three major cancer centers in Israel. The participants completed the CPASS and two other standardized instruments: The ENRICH Marital Satisfaction Scale (EMS) and the Brief Symptom Inventory (BSI).

Results: Principal component analysis confirmed a three‐factor structure based upon the agent of support (spouse; friends/family; spiritual/religious beliefs). Cronbach's α coefficients for the agent of support indexes were high (0.80–0.95), while Cronbach's α levels for the kind of support were lower (0.45–0.72). Smallest Space Analysis (SSA) also confirmed the theoretical structure of the CPASS. Pearson correlation coefficients to the other study variables were high and significant.

Conclusions: As a whole, the CPASS was found to be a valid tool for the current Israeli sample. Theoretical and practical conclusions and socio‐cultural implications are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Field evaluation of vaporised ethyl formate and carbon dioxide for fumigation of stored wheat
Authors: Dojchinov Greg , Damcevski Katherine A , Woodman James D , Haritos Victoria S
Published: December 2009

BACKGROUND: Vapormate™ is a cylinderised non‐flammable mixture of ethyl formate (16.7% by weight) and carbon dioxide (CO2) that has been developed as a rapid fumigant of stored grain. Four field trials were undertaken on wheat in 50 t farm silos to demonstrate the feasibility of dynamic application. To assess treatment efficacy, each trial tested mixed stages of Rhyzopertha dominica F. (>11 000), Tribolium castaneum (Herbst.) (>1500) and Sitophilus oryzae (L.) (>13 000) in mesh cages positioned through the centre of the grain bulk and on the grain surface. Ethyl formate and CO2 concentrations were measured in the silo during fumigation and in ambient air outside the 6 m fumigation zone. Application rates of 420, 660 and 940 g m−3 of ethyl formate/CO2 formulation and exposure times of 24, 3 and 72 h, respectively, were examined using wheat of 10.4–11.7% moisture content and grain temperatures between 2 and 32 °C.

RESULTS: All life stages of R. dominica and T. castaneum were fully controlled under all conditions tested, and mortality of all life stages of S. oryzae was greater than 98%.

CONCLUSION: Dynamic application of vaporised ethyl formate and CO2 to 50 t silos proved safe to operators and rapidly effective against stored‐grain insects on cold to warm grain. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd
HREELS study of graphene formed on hexagonal silicon carbide
Authors: Koch R. J. , Haensel T. , Ahmed S. I.‐U. , Seyller Th. , Schaefer J. A.
Published: December 2009

Using high resolution electron energy loss spectroscopy (HREELS) in conjunction with low energy electron diffraction (LEED) and X‐ray induced photoelectron spectroscopy (XPS), we have studied surface reconstructions from Si‐rich to C‐rich surfaces up to graphene formation. It is shown that the coupling between the longitudinal optical phonons and the carrier plasmons that originate from the presence of the layered semimetallic character of graphene and few layer graphene (FLG) drastically influence the HREELS‐spectra. For the hydrogen smoothened SiC‐samples, which have been subsequently annealed under high Ar‐pressure [1], the Fuchs‐Kliewer surface phonon ω0 is completely screened and two other losses ω‐ and ω+, called plasmarons, appear. They originate from the coupling between surface optical phonons and plasma oscillations of free‐electrons resulting from the graphene/SiC interface. For the heated SiC‐samples under ultra‐high‐vacuum (UHV) conditions, the situation is different, which indicates cluster formation of graphene / graphite at the surface. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Charge transient spectroscopy measurements of metal‐oxide‐semiconductor
Authors: Arnold Markus , Fechner Axel , Zahn Dietrich R. T.
Published: December 2009

Charge transient spectroscopy (QTS) is an electrical measurement technique related to deep‐level transient spectroscopy (DLTS). Using QTS it is possible to measure fast charge reloading processes even in the absence of depletion regions as a function of time and temperature with different pulse voltages and pulse widths. As a result, one can determine the number, the energetic position, the capture cross section, and the density of the electrically active traps.

Here QTS measurements of Al/SiO2/Si Metal‐OxideSemiconductor structures are presented revealing the influence of manganese implantation into p‐ and n‐doped silicon on the charge carrier transport and trapping properties. The QTS results are compared to I‐V, C‐V and DLTS measurements on the same samples and the differences are discussed (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Formation of an interface layer between Al1‐xSixOy thin films and the Si substrate during rapid thermal annealing
Authors: Michałowski Paweł Piotr , Beyer Volkhard , Czernohorsky Malte , Kücher Peter , Teichert Steffen , Jaschke Gert , Möller Wolfhard
Published: December 2009

Silicon diffusion from the substrate through Al1‐xSixOy thin films was investigated by ToF‐SIMS depth profiling. Two types of substrate stacks were analyzed: Si wafer with either native oxide or with additional silicon nitride layer. The amount of diffused silicon depends strongly on the type of the substrate. The activation energy for pure alumina was found to be 2.27 ± 0.02 eV and 3.73 ± 0.02 eV for SiO2/Si and Si3N4/SiO2/Si samples, respectively.

Furthermore it was proved that the activation energy increases with higher concentration of Si for SiO2/Si samples whereas it decreases for Si3N4/SiO2/Si. Detailed analysis of SIMS depth profiles provide satisfactory explanation of this phenomenon: SiO2 has much stronger tendency to react with Al1‐xSixOy material forming an interface layer that restrain further diffusion of Si from the substrate (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum transport in narrow‐gap semiconductor nanocolumns
Authors: Lüth H. , Blömers Ch. , Richter Th. , Wensorra J. , Estevez Hernandez S. , Petersen G. , Lepsa M. , Schäpers Th. , Marso M. , Indlekofer M. , Calarco R. , Demarina N. , Grützmacher D.
Published: December 2009

InN nanowires were grown by plasma‐assisted MBE in a bottom‐up approach, while InAs nanocolumns were prepared top‐down by electron beam lithography. Both types of narrow‐gap semiconductor nanocolumns exhibit a surface accumulation with a cylinder‐like 2 DEG as conduction channel. In magnetoconductance measurements at low temperatures with the magnetic field parallel to the column axis the InN wires exhibit magnetoconductance oscillations with a repetition period of a magnetic flux quantum ϕ0. For the InAs columns the observed magnetoconductance oscillations have a period of half the flux quantum ϕ0/2. The interpretation is based on the different surface perfectness of both types of columns. The InN wires with an almost perfect crystallinity allow transport through coherent angular momentum states within the surface 2 DEG which yields a ϕ0 periodicity. The InAs column surfaces exhibit a high amount of surface defects arising from the preparation and only diffusive, phase conserving transport through the 2 DEG is possible, which allows Al'tshuler‐Aronov‐Spivak interferences with a period ϕ0/2. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
UV transparent single‐crystalline bulk AlN substrates
Authors: Bickermann Matthias , Epelbaum Boris M. , Filip Octavian , Heimann Paul , Nagata Shunro , Winnacker Albrecht
Published: December 2009

Bulk aluminum nitride (AlN) is a very promising substrate material for UV optoelectronics, and its UV transparency is of high interest for UV devices designed to emit through the substrate. We report on 500 μm thick bulk AlN substrates with plain UV transmittance exceeding 50% (i.e., absorption coefficients below 14 cm–1) for wavelengths from 220 nm to 380 nm in the main wafer area. Comparing the spectra of different AlN bulk samples, four major below band‐gap absorption bands are identified and interpreted based on a point defect model for AlN crystals. We conclude that a further reduction of oxygen contamination of the source material led to a significant decrease of UV absorption in both colorless and yellowish areas of those substrates. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Built‐in fields in non‐polar InxGa1–xN quantum dots
Authors: Schulz Stefan , O'Reilly Eoin P.
Published: December 2009

We present a detailed analysis of the internal built‐in potential in polar and non‐polar Inx Ga1–x N quantum dots (QDs). The applied model is based on a surface integral method to calculate the three‐dimensional electrostatic built‐in potential in semiconductor QDs of arbitrary shape. This technique allows for a detailed and systematic analysis of the different contributions to the total built‐in field. Here, we also investigate the impact of the QD geometry on the built‐in potential in structures grown along non‐polar directions of the crystal.

Since there is uncertainty in the literature as to the sign of the piezoelectric constant e15 associated with the shear strain, we study the influence of this constant in detail. While recent results on non‐polar GaN/AlN QDs indicate that only a negative e15 leads to significant reduction in the built‐in field, we show that for InN/GaN QDs there should still be a significant field present, independent of the sign of the piezoelectric constant e15. However, this field is strongly reduced with increasing Ga concentration in the nanostructure. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of gas flow rates on the formation of III‐nitride nanowires
Authors: Chen Liang‐Yih , Liao Cheng‐I , Peng Hsuan‐Ying
Published: December 2009

This study achieved catalytic growth of gallium nitride nanowires (GaN‐NWs) and indium gallium nitride nanowires (InxGa1‐xN‐NWs) by the horizontal furnace chemical vapour deposition (HF‐CVD) method at the temperature of 900 °C and 550 °C, respectively. The morphologies and structures of III‐nitride nanowires depended on the gas flow rates were studied. Comparing the growth mechanisms of GaN‐NWs and InxGa1‐xN‐NWs, the vapour‐solid (VS) mechanism is dominant in GaN nanowires, except with a low ammonium flow rate, and the vapour‐liquid‐solid (VLS) mechanism is dominant in InxGa1‐xN nanowires. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant MEMS based on cubic GaN layers
Authors: Niebelschütz F. , Brueckner K. , Jatal W. , Tschumak E. , As D. J. , Hein M. A. , Pezoldt J.
Published: December 2009

In this work, we report the fabrication of GaN microelectromechanical structures (MEMS) based on cubic GaN grown by molecular beam epitaxy on 3C‐SiC(100)/Si(100) pseudosubstrates. Free‐standing beam resonators with a width of 5 μm and lengths from 250 to 1000 μm were patterned and characterized. Magnetomotively and electrostatically actuated resonators were analyzed under ambient and vacuum conditions resulting in quality factors of up to 250 under ambient conditions up to 40.000 under vacuum (1.9x10‐5 mbar) and resonant frequencies from 97 to 406 kHz for the fundamental resonant mode. These results allow for the determination of the Young's modulus and the residual strain of the free standing structures. The measured GaN resonators exhibited Young's moduli from 235 to 260 GPa and high residual axial strains from 1.0x10‐3 to 1.25x10‐3. For the cubic GaN layers from which the resonators were fabricated, residual strains between 3.3x10‐3 and 5.8x10‐3 have been extracted from XRD measurements. These values are on the same order of magnitude but a definite factor higher compared to the measurement results obtained for the fabricated GaN‐beams, which indicates a partial layer relaxation caused by the influences of the MEMS fabrication processes. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐polar cubic AlGaN/GaN HFETs grown by MBE on Ar+ implanted 3C‐SiC (001)
Authors: Tschumak Elena , Lindner J. K. N. , Bürger M. , Lischka K. , Nagasawa H. , Abe M. , As D. J.
Published: December 2009

The growth of cubic group III‐nitrides is a direct way to eliminate polarization effects, which inherently limit the fabrication of normally‐off heterojunction field‐effect transistors (HFETs) in GaN technology. HFET structures were fabricated of non‐polar cubic AlGaN/GaN hetero layers grown by plasma assisted molecular beam epitaxy (MBE) on free standing 3C‐SiC (001). The electrical insulation of 3C‐SiC was realised by Ar+ implantation before c‐AlGaN/GaN MBE. The structural properties of the epilayers were studied by high‐resolution x‐ray diffraction (HRXRD). HFETs with normally‐off and normally‐on characteristics were fabricated of cubic AlGaN/GaN. Capacitance‐voltage (CV) characteristics of the gate contact were performed to detect the electron channel at the c‐AlGaN/GaN hetero interface. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Factors affecting the luminescence emission of InGaN multi‐quantum wells grown on (0001) sapphire substrates by MOVPE
Authors: Martínez Oscar , Avella Manuel , Jiménez Juan , Bosi Matteo , Fornari Roberto
Published: December 2009

The luminescence emission of InGaN/GaN multi‐quantum wells (MQW) is affected by several factors, i.e. the composition, the QW thickness, the piezoelectric field and the high density of threading dislocations. In the case of heterostructures containing several QWs piled up, one has to consider the homogeneity of each QW and the thickness of the barrier layers between them, which have influence on the strain. We present herein a Cathodoluminescence (CL) study of a series of InGaN QW structures, paying special emphasis to the problem of the lateral distribution of In, and how it influences the emission properties of the QWs. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Novel InN/InGaN multiple quantum well structures for slow‐light generation at telecommunication wavelengths
Authors: Naranjo F. B. , Kandaswamy P. K. , Valdueza‐Felip S. , Lahourcade L. , Calvo V. , González‐Herráez M. , Martín‐López S. , Corredera P. , Monroy E.
Published: December 2009

The third order susceptibility is responsible for a variety of optical non‐linear phenomena ‐ like self focusing, phase conjugation and four‐wave mixing ‐ with applications in coherent control of optical communication. InN is particularly attractive due to its near‐IR bandgap and predicted high nonlinear effects. Moreover, the synthesis of InN nanostructures makes possible to taylor the absorption edge in the telecomunication spectral range and enhance nonlinear parameters thanks to carrier confinement. In this work, we assess the nonlinear optical behavior of InN/InxGa(1‐x)N (0.9 > x > 0.7) multiple‐quantum‐well (MQW) structures grown by plasma‐assisted MBE on GaN‐on‐sapphire templates. Low‐temperature (5 K) photoluminescence measurements show near‐IR emission whose intensity increases with the In content in the barriers, which is explained in terms of the existence of piezoelectric fields in the structures. The nonlinear optical absorption coefficient, α2, were measured at 1.55 μm using the Z‐scan method. We observe a strong dependence of the nonlinear absorption coefficient on the In content in the barriers. Saturable absorption is observed for the sample with x = 0.9, with α2 ∼ ‐9 x 103 cm/GW. For this sample, an optically controlled reduction of the speed of light by a factor S ∼ 80 is obtained at 1.55 μm (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light extraction from GaN‐based LED structures on silicon‐on‐insulator substrates
Authors: Tripathy S. , Teo S. L. , Lin V. K. X. , Chen M. F. , Dadgar A. , Christen J. , Krost A.
Published: December 2009

Nano‐patterning of GaN‐based devices is a promising technology in the development of high output power devices. Recent researches have been focused on the realization of two‐dimensional (2D) photonic crystal (PhC) structure to improve light extraction efficiency and to control the direction of emission. In this study, we have demonstrated improved light extraction from green light emitting diode (LED) structures on thin silicon‐on‐insulator (SOI) substrates using surface nanopatterning. Scanning electron microscopy (SEM) is used to probe the size, shape, and etch depth of nano‐patterns on the LED surfaces. Different types of nanopatterns were created by e‐beam lithography and inductively coupled plasma etching. The LED structures after post processing are studied by photoluminescence (PL) measurements. The GaN nanophotonic structures formed by ICP etching led to more than five‐fold increase in the intensity of the green emission. The improved light extraction is due to the combination of SOI substrate reflectivity and photonic structures on top GaN LED surfaces. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EM algorithm for estimating the Burr XII parameters with multiple censored data
Authors: Wang F. K. , Cheng Y. F.
Published: December 2009

The two‐parameter Burr XII distribution has been widely used in various practical applications such as business, chemical engineering, quality control, medical research and reliability engineering. In this paper, we present maximum likelihood estimation (MLE) via the expectation–maximization (EM) algorithm to estimate the Burr XII parameters with multiple censored data. We also provide a method that can be used to construct the confidence intervals of the parameters, a method that computes the asymptotic variance and the covariance of the MLE from the complete and missing information matrices. A simulation study is conducted to compare the performance of the MLE via the EM algorithm and the Netwon–Raphson (NR) algorithm. The simulation results show that the EM algorithm outperforms the NR algorithm in most cases in terms of bias and errors in the root mean square. A numerical example is also used to demonstrate the performance of the proposed method. Copyright © 2009 John Wiley & Sons, Ltd.
Infrared multiple photon dissociation spectroscopy of sodium and potassium chlorate anions
Authors: Dain Ryan P. , Leavitt Christopher M. , Oomens Jos , Steill Jeffrey D. , Groenewold Gary S. , Van Stipdonk Michael J.
Published: December 2009

The structures of gas‐phase, metal chlorate anions with the formula [M(ClO3)2]−, M = Na and K, were determined using tandem mass spectrometry and infrared multiple photon dissociation (IRMPD) spectroscopy. Structural assignments for both anions are based on comparisons of the experimental vibrational spectra for the two species with those predicted by density functional theory (DFT) and involve conformations that feature either bidentate or tridentate coordination of the cation by chlorate. Our results strongly suggest that a structure in which both chlorate anions are bidentate ligands is preferred for [Na(ClO3)2]−. However, for [K(ClO3)2]− the best agreement between experimental and theoretical spectra is obtained from a composite of predicted spectra for which the chlorate anions are either both bidentate or both tridentate ligands. In general, we find that the overall accuracy of DFT calculations for prediction of IR spectra is dependent on both functional and basis set, with best agreement achieved using frequencies generated at the B3LYP/6‐311+g(3df) level of theory. Copyright © 2009 John Wiley & Sons, Ltd.
Delay‐dependent robust H∞ control for uncertain stochastic time‐delay systems
Authors: Yang Rongni , Gao Huijun , Shi Peng
Published: December 2009

This paper investigates the robust H∞ control problem for stochastic systems with a delay in the state. Sufficient delay‐dependent conditions for the existence of state‐feedback controllers are proposed to guarantee mean‐square asymptotic stability as well as the prescribed H∞ performance for the closed‐loop systems. Moreover, the results are further extended to the stochastic time‐delay systems with parameter uncertainties, which are assumed to be time‐varying norm‐bounded appearing in both the state and the input matrices. The appealing idea is to partition the delay, which differs greatly from the most existing results and reduces conservatism by thinning the delay partitioning. Numerical examples are provided to show the advantages of the proposed techniques. Copyright © 2009 John Wiley & Sons, Ltd.