bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Left Ventricular Impedance in Comparison With Ultrasound Images
Authors: Choi Seong Wook , Park Sung Min
Published: December 2011

Cardiac monitoring of ventricular assist devices (VADs) is important for detecting heart failure risks, such as critical arrhythmia and ventricular fibrillation, and for supplying data that are useful for hemodynamic control. Specifically, impedance cardiograms (ICGs) are especially beneficial because they have no effect on the tissue or organs and can monitor various parameters simultaneously, including the heart rate and heart contractions. In this article, we measured impedance changes in porcine left ventricles using electrodes placed around the inlet and outlet cannulae of the VAD. The measured left ventricular impedance (LVI) waveform changes are caused by heart movements, such as cardiac muscle contraction and changes in blood volume as a result of heart filling and emptying. In contrast to other impedance measurements, LVI is less affected by the movement of other organs. Using a porcine model, LVIs were measured and compared with blood flow data measured with an ultrasound blood flowmeter. The ICG showed the same frequency as the animal's heart rate, and their amplitudes were closely related to cardiac output (CO). However, the waveform differed from other vital signs, such as CO, electrocardiogram, and blood pressure. Ultrasound images were used to explain the impedance waveform. In the ultrasound images, we obtained the shape and size of the animal's heart and calculated the predicted impedance data. We then compared these to the actual measured data. These results show that the impedance signal contains detailed information on heart rate and CO; these results were unaffected by the cannulae or VAD perfusion.
Gender Differences in Healthcare Utilization: The Mediating Effect of Utilization Propensity
Authors: GLAESMER HEIDE , BRÄHLER ELMAR , MARTIN ALEXANDRA , MEWES RICARDA , RIEF WINFRIED
Published: December 2011

To evaluate the mediating effect of utilization propensity (UP) on gender differences in healthcare utilization (HCU), a representative sample of the German general population (N = 2,510) was assessed with questionnaires. Gender differences in HCU, UP, and the mediating effect of UP were investigated using regression analyses. UP was significantly associated with HCU. The explanatory power of gender for UP, and of UP for HCU was prevailingly weak. UP had a mediating effect on gender differences in HCU, but the effect was very small. This is partly attributable to common problems in the prediction of behavior by attitudes and the operationalization of UP.
The importance of plant–soil interactions, soil nutrients, and plant life history traits for the temporal dynamics of Jacobaea vulgaris in a chronosequence of old‐fields
Authors: van de Voorde Tess F. J. , van der Putten Wim H. , Bezemer T. Martijn
Published: December 2011

We examined to what extent temporal dynamics of Jacobaea vulgaris cover in old‐fields were related to plant–soil feedback, soil nutrients, seed availability and performance, and seedling establishment. Long‐term measurements at an experimental field and in ten old‐fields representing a chronosequence following land abandonment revealed a remarkably similar hump‐shaped temporal pattern of J. vulgaris cover, which peaked at about five years after abandonment. In a plant–soil feedback study, J. vulgaris biomass of plants grown in soil from all chronosequence fields was lower than in sterilized control soil. However, biomass of J. vulgaris in the feedback study was lower when grown in soil collected from fields with a high density of J. vulgaris plants than in soil from fields with a low density of J. vulgaris. When plants were grown again in the conditioned soil, a strong negative plant–soil feedback response was observed for soils from all fields. These results indicate that soils from all stages of the chronosequence can develop a strong negative soil feedback to J. vulgaris, and that there is a positive relationship between J. vulgaris density and the subsequent level of control by the soil community. In a common‐garden experiment with turfs collected from the chronosequence fields in which J. vulgaris was seeded, seedling establishment was significantly lower in turfs from older than from young fields. In a seed bank study the number of emerging seedlings declined with time since abandonment of the field. In conclusion, negative plant–soil feedback is an important factor explaining the hump‐shaped population development of J. vulgaris. However, it is not operating alone, as propagule availability and characteristics, and competition may also be important. Thus, in order to explain its contribution to plant population dynamics, the role of biotic plant–soil interactions, soil nutrients and life history characteristics along successional gradients should be considered from a community perspective.
Reliability and validity of a Japanese version of the Oral Health Impact Profile for edentulous subjects
Authors: Sato Yusuke , Kaiba Yoshinori , Yamaga Eijiro , Minakuchi Shunsuke
Published: December 2011

doi: 10.1111/j.1741‐2358.2011.00606.x

Reliability and validity of a Japanese version of the Oral Health Impact Profile for edentulous subjects

Objective:  To evaluate the reliability and validity of the Japanese version of the Oral Health Impact Profile for edentulous (OHIP‐EDENT‐J) patients.

Background:  Oral Health Impact Profile for edentulous is an appropriate instrument for assessing the Quality of life (QOL) in edentulous patients. However, the reliability and validity of the Japanese version had not been evaluated.

Methods:  The study was conducted on 116 edentulous patients (Group A, requiring new dentures, n = 61; Group B, already having dentures, n = 55). Cronbach’s alpha (α) was used to measure internal consistency of the summary scores for OHIP‐EDENT‐J and various subscales in Groups A and B. The interclass correlation coefficient (ICC) and 95% confidence interval of the summary scores for OHIP‐EDENT‐J and subscales were calculated. The summary scores for OHIP‐EDENT‐J in Groups A and B were compared with evaluate content validity. The Spearman’s correlation coefficient between the summary scores for OHIP‐EDENT‐J and the satisfaction with dentures (100 mm VAS) was calculated for Groups A and B to evaluate concurrent validity.

Results:  The reliability of the summary scores for OHIP‐EDENT‐J was good (α = 0.93). The ICC of the summary scores for OHIP‐EDENT‐J was 0.85. Summary scores for OHIP‐EDENT‐J were significantly different (p = 0.027) between Group A and Group B, with Group A having the higher value. The Spearman’s correlation coefficient for the degree of satisfaction with dentures and the summary scores for OHIP‐EDENT‐J, calculated for Groups A and B (n = 107), was −0.609.

Conclusion:  The OHIP‐EDENT‐J, a questionnaire on oral health–related QOL comprising 19 items, showed good reliability and validity for edentulous patients.
Association between oral health and body cell mass in hospitalised elderly
Authors: Solemdal Kirsten , Sandvik Leiv , Møinichen‐Berstad Christina , Skog Karina , Willumsen Tiril , Mowe Morten
Published: December 2011

doi: 10.1111/j.1741‐2358.2011.00607.x

Association between oral health and body cell mass in hospitalised elderly

Objective:  To examine whether oral health in hospitalised elderly was associated with body cell mass (BCM) measured with Bioimpedance spectroscopy.

Background:  Body cell mass is the tissue producing the metabolic work necessary for all body functions. BCM is mainly muscle tissue. Low BCM is associated with diseases, ageing and poor nutritional status. Reduced oral health is also associated with these parameters; thus, BCM and oral health may be related.

Methods:  Body cell mass was measured using Bioimpedance spectroscopy in 138 acutely hospitalised elderly ≥70 years. The number of own teeth, posterior occluding tooth pairs and decayed teeth were registered. Oral hygiene was registered with Mucosal–Plaque Score, an index based on assessment of plaque accumulation and mucosal/gingival inflammation. Mini Nutritional Assessment‐Short Form, body mass index and handgrip strength were used as nutritional indicators. Comorbidity was assessed with Cumulative Index Rating Scale.

Results:  Mean age was 83.2 ± 5.9 years, ranging from 70 to 101 years. Dentition status was significantly and positively associated with BCM. Reduced oral hygiene was significantly associated with low BCM. These findings remained significant after adjusting for confounders.

Conclusion:  These results show that compromised oral health was significantly associated with reduced BCM in hospitalised elderly.
Gamma-ray burst observations by Fermi Large Area Telescope revisited: new candidates found
Authors: Rubtsov G. I. , Pshirkov M. S. , Tinyakov P. G.
Published: December 2011

We search the Fermi Large Area Telescope (LAT) photon data base for an extended gamma-ray emission which could be associated with any of the 581 previously detected gamma-ray bursts (GRBs) visible to the Fermi-LAT. For this purpose, we compare the number of photons with energies E > 100 MeV and E > 1 GeV which arrived in the first 1500 s after the burst from the same region, to the expected background. We require that the expected number of false detections does not exceed 0.05 for the entire search and find the high-energy emission in 19 bursts, four of which (GRB 081009, GRB 090720B, GRB 100911 and GRB 100728A) were previously unreported. The first three are detected at energies above 100 MeV, while the last one shows a statistically significant signal only above 1 GeV.
Dementia, Stroke, and Vascular Risk Factors; a Review
Authors: Sahathevan Ramesh , Brodtmann Amy , Donnan Geoffrey A.
Published: December 2011

Interest in dementia has increased over the past few decades. Stroke is an important cause of cognitive problems. The term vascular cognitive impairment is now used to describe dementia attributed to stroke or deep white matter lesions detected on imaging. Although vascular cognitive impairment is increasingly diagnosed, Alzheimer's disease remains the most common dementia worldwide. The relationship between Alzheimer's disease and vascular cognitive impairment is unclear, although there exists significant overlap, which prompts physicians to consider them opposite ends of a disease spectrum, rather than separate entities. There is also substantial evidence that stroke risk factors such as hypertension, diabetes; lipid disorders, etc. are independently associated with an increased risk of Alzheimer's disease and vascular cognitive impairment. Evidence suggests that these risk factors have a cumulative effect on Alzheimer's disease development but not on vascular cognitive impairment. This is more marked in Alzheimer's disease patients in the presence of the ε4 allelic variant of apolipoprotein E. How these risk factors increase the risk of dementia is largely unknown. Physicians must be aware that stroke causes dementia; that vascular risk factors appear to be independent risk factors in developing dementia, and that poststroke care must include cognitive assessment.
Quantification of Glucose Diffusion in Human Lung Tissues by Using Fourier Domain Optical Coherence Tomography
Authors: Guo Xiao , Wu Guoyong , Wei Huajiang , Deng Xiaoyuan , Yang Hongqin , Ji Yanhong , He Yonghong , Guo Zhouyi , Xie Shusen , Zhong Huiqing , Zhao Qingliang , Zhu Zhenguo
Published: December 2011

In this study, we report permeability coefficients of 30% glucose diffusion by the optical coherence tomography signal slope (OCTSS) method in four kinds of human lung tissue in vitro: normal lung tissue, benign granulomatosis lung tissue, squamous cell carcinoma and adenocarcinoma tumor. To quantify the permeability coefficient of the agent, the monitored region was 80 μm thickness at a tissue depth of ca 230 μm from the surface. The permeability coefficients of 30% glucose from 10 independent experiments were averaged and found to be (1.35 ± 0.13) × 10−5 cm s−1 from the normal lung tissue, (1.78 ± 0.21) × 10−5 cm s−1 from the benign granulomatosis lung tissue, (2.88 ± 0.19) × 10−5 cm s−1 from the adenocarcinoma tumor and (3.53 ± 0.25) × 10−5 cm s−1 from the squamous cell carcinoma, respectively. It could be clearly seen that the permeability coefficients of 30% glucose increase ca 32%, 113% and 162% in the benign granulomatosis, adenocarcinoma tumor and squamous cell carcinoma of human lung tissue compared with that from the normal lung tissue, respectively. Therefore, we inferred from this pilot study that the OCT imaging is a feasible method to distinguish normal and cancer lung tissue.
Application and validation of mortality functions to assess the consequences of flooding to people
Authors: Di Mauro M. , de Bruijn K.M.
Published: December 2011

The assessment of potential consequences of a flood event to the exposed population is a key question for flood risk managers. This issue is increasingly a triggering research on assessing potential numbers of fatalities because of flooding. In the past, mortality functions were proposed to estimate the fatalities in areas that are exposed to a hazard because of flood defence failures‐in the Netherlands. This paper describes a study undertaken to validate those mortality functions and assesses their applicability for appraising consequences of flooding to people in a UK‐specific context. The functions were applied to the 1953 North Sea Storm and, in particular, to the Canvey Island that suffered from 58 fatalities as consequence of this flood event. This paper describes the results of this research and provides a review of the criteria used to apply the functions, as well as guidelines for applying these functions in a UK context.
Type III effector genes and other virulence factors of Shiga toxin‐encoding Escherichia coli isolated from wastewater
Authors: Martínez‐Castillo Alexandre , Allué‐Guardia Anna , Dahbi Ghizlane , Blanco Jorge , Creuzburg Kristina , Schmidt Herbert , Muniesa Maite
Published: December 2011

Pathogenic Shiga toxin‐producing Escherichia coli (STEC) strains share the genes encoding Shiga toxins (stx) and many other virulence factors. The classification and evolutionary studies of pathogenic E. coli based on their virulence genes have been conducted with E. coli isolated from human and animal infections or outbreaks. In this study, we used 103 STEC strains isolated from faecally polluted water environments to analyse 23 virulence genes (stx1, cdt, hlyA, saa, eae, three type III effector genes encoded within the locus of enterocyte effacement (LEE) and 15 non‐LEE‐encoded type III effector genes). Despite the presence of several stx2 variants, our isolates demonstrated low prevalence of the virulence genes (only 46.6% of the strains were positive for virulence determinants). Among these, the largest repertoire was found in a few O157:H7 isolates (most from cattle wastewater and one from sewage), while other serotypes showed fewer virulence determinants. The occurrence of most virulence genes seemed to be independent from one another. This was clear for hlyA (the most prevalent), cdt and cif (the least prevalent). Other effector genes, could be found or not in combination with others, suggesting that they can be mobilized independently. Our data suggest that E. coli strains can evolve separately by independently acquiring mobile genetic elements.
In-vivo laxative and toxicological evaluation and in-vitro antitumour effects of Mitracarpus frigidus aerial parts
Authors: Fabri Rodrigo Luiz , de Oliveira Aragão Danielle Maria , Florêncio Jônatas Rodrigues , Cardoso Gabriele Mendes Matos , de Souza-Fagundes Elaine Maria , Castanon Maria Christina Marques Nogueira , Scio Elita
Published: December 2011

Objectives

To evaluate the in-vitro antitumour properties, and the in-vivo laxative and toxicological effects of the methanolic extract of the aerial parts of Mitracarpus frigidus (MFM).

Methods

The in-vitro antitumour activity of MFM was evaluated against three human tumour cell lines: Jurkat, HL60 and MCF-7. The laxative activity and the effect of MFM on intestinal motility were evaluated in rats at the doses of 100, 300 and 1000 mg/kg. Acute oral toxicity was performed at 10, 100, 1000 and 2000 mg/kg and subchronic toxicity was evaluated at 100, 300 and 1000 mg/kg of MFM during a 42-day period. After subchronic administration of MFM the biochemical, haematological and histopathological parameters were analysed. Also, the total content of anthraquinones was determined.

Key findings

MFM was cytotoxic only against HL60 and Jurkat cells with 89 and 83% growth inhibition, respectively. The laxative activity of MFM was similar to bisacodyl. Regarding the effect on intestinal motility, MFM showed a significant increase in the pathway of charcoal compared with the group treated with saline. Furthermore, MFM showed no in-vivo toxicity at the doses tested. Free and anthraquinone C- and O-glycosides were detected in MFM.

Conclusions

MFM showed significant antitumour activity for leukaemic cells. Moreover, it presented laxative potential and no in-vivo toxicity.
Tracking the Fault Lines of Pro‐Poor Carbon Forestry
Authors: Paladino Stephanie
Published: December 2011

Reducing emissions from deforestation and forest degradation (REDD) has been given a principal role in post‐Kyoto, climate change agreements. Resulting markets and mechanisms for carbon forestry offsets could generate considerable global revenues for both forest conservation and sustainable rural development; or they may impose political and economic pressures on forest governance that threaten indigenous and rural peoples’ rights. Some inherent challenges to developing carbon forestry projects that support rural peoples’ welfare are reviewed. The experience of Scolel Te’, a carbon forestry project for Mexican indigenous farmers, suggests how projects can be adapted for smallholder provision of carbon services on benign terms and still meet the demands of carbon markets. However, carbon sales alone have not supported investments in knowledge development, institutional learning, and strategic farmer participation needed for significant political or economic change. This supports critiques that policies based on economic valuations of environmental services are unlikely to support social and equity objectives.
Approaches to Modeling the Gas-Turbine Maintenance Process
Authors: Yu Tai-Tuck , Scanlan James P. , Crowder Richard M. , Wills Gary B.
Published: December 2011

Discrete-event modeling has long been used for logistics and scheduling problems, while multi-agent modeling closely matches human decision-making process. In this paper, a metric-based comparison between the traditional discrete-event and the emerging agent-based modeling approaches is reported. The case study involved the implementation of two functionally identical models based on a realistic, nontrivial, civil aircraft gas turbine global repair operation. The size, structural complexity, and coupling metrics from the two models were used to gauge the benefits and drawbacks of each modeling paradigm. The agent-based model was significantly better than the discrete-event model in terms of execution times, scalability, understandability, modifiability, and structural flexibility. In contrast, and importantly in an engineering context, the discrete-event model guaranteed predictable and repeatable results and was comparatively easy to test because of its single-threaded operation. However, neither modeling approach on its own possesses all these characteristics nor can each handle the wide range of resolutions and scales frequently encountered in problems exemplified by the case study scenario. It is recognized that agent-based modeling can emulate high-level human decision-making and communication closely while discrete-event modeling provides a good fit for low-level sequential processes such as those found in manufacturing and logistics.
A Phenomenological Model for the Hysteresis Behavior of Metal Sheets Subjected to Unloading/Reloading Cycles
Authors: Eggertsen P.-A. , Mattiasson K. , Hertzman J.
Published: December 2011

The springback phenomenon is defined as elastic recovery of the stresses produced during the forming of a material. An accurate prediction of the springback puts high demands on the material modeling during the forming simulation, as well as during the unloading simulation. In classic plasticity theory, the unloading of a material after plastic deformation is assumed to be linearly elastic with the stiffness equal to Young’s modulus. However, several experimental investigations have revealed that this is an incorrect assumption. The unloading and reloading stress–strain curves are in fact not even linear, but slightly curved, and the secant modulus of this nonlinear curve deviates from the initial Young’s modulus. More precisely, the secant modulus is degraded with increased plastic straining of the material. The main purpose of the present work has been to formulate a constitutive model that can accurately predict the unloading of a material. The new model is based on the classic elastic-plastic framework, and works together with any yield criterion and hardening evolution law. To determine the parameters of the new model, two different tests have been performed: unloading/reloading tests of uniaxially stretched specimens, and vibrometric tests of prestrained sheet strips. The performance of the model has been evaluated in simulations of the springback of simple U-bends and a drawbead example. Four different steel grades have been studied in the present investigation.
The Springback Characteristics of a Porous Tantalum Sheet-Metal
Authors: Nebosky Paul S. , Schmid Steven R. , Sellés M.-A.
Published: December 2011

This study examines the elastic recovery (springback) of a porous tantalum foam after sheet forming operations. The foam and sheet-like form is applicable to bone ingrowth surfaces on orthopedic implants and is desirable due to its combination of high strength, low relative density, and excellent osteoconductive properties. Forming of the foam improves nestability during manufacture and is essential to have the material achieve the desired shape. Experimentally, bending about a single axis using a wiping die is studied by observing cracking and measuring springback. Die radius and clearance strongly affect the springback properties, while punch speed, embossing, die radius, and clearance all influence cracking. To study the effect of the foam microstructure, bending also is examined numerically. A horizontal hexagonal mesh comprised of beam elements is employed, which allows for the densification that occurs during forming. The flow strength of individual tantalum struts is directly measured in an atomic force microscope. The numerical results show that as the hexagonal cells are elongated along the sheet length, elastic springback decreases. By changing the material properties of the struts, the models can be modified for use with other open-cell metallic foams.
Formability and Surface Finish Studies in Single Point Incremental Forming
Authors: Bhattacharya A. , Maneesh K. , Venkata Reddy N. , Cao Jian
Published: December 2011

Incremental sheet metal forming (ISMF) has demonstrated its great potential to form complex three-dimensional parts without using a component specific tooling. The die-less nature in incremental forming provides a competitive alternative for economically and effectively fabricating low-volume functional sheet parts. However, ISMF has limitations with respect to maximum formable wall angle, geometrical accuracy, and surface finish of the component. In the present work, an experimental study is carried out to study the effect of incremental sheet metal forming process variables on maximum formable angle and surface finish. Box–Behnken method is used to design the experiments for formability study and full factorial method is used for surface finish study. Analysis of experimental results indicates that formability in incremental forming decreases with increase in tool diameter. Formable angle first increases and then decreases with incremental depth and it is also observed that the variation in the formable angle is not significant in the range of incremental depths considered to produce good surface finishes during the present study. A simple analysis model is used to estimate the stress values during incremental sheet metal forming assuming that the deformation occurs predominantly under plane strain condition. A stress-based criterion is used along with the above mentioned analysis to predict the formability in ISMF and its predictions are in very good agreement with the experimental results. Surface roughness decreases with increase in tool diameter for all incremental depths. Surface roughness increases first with increase in incremental depth up to certain angle and then decreases. Surface roughness value decreases with increase in wall angle.
Static and Dynamic Error of a Biplanar Videoradiography System Using Marker-Based and Markerless Tracking Techniques
Authors: Miranda Daniel L. , Schwartz Joel B. , Loomis Andrew C. , Brainerd Elizabeth L. , Fleming Braden C. , Crisco Joseph J.
Published: December 2011

The use of biplanar videoradiography technology has become increasingly popular for evaluating joint function in vivo. Two fundamentally different methods are currently employed to reconstruct 3D bone motions captured using this technology. Marker-based tracking requires at least three radio-opaque markers to be implanted in the bone of interest. Markerless tracking makes use of algorithms designed to match 3D bone shapes to biplanar videoradiography data. In order to reliably quantify in vivo bone motion, the systematic error of these tracking techniques should be evaluated. Herein, we present new markerless tracking software that makes use of modern GPU technology, describe a versatile method for quantifying the systematic error of a biplanar videoradiography motion capture system using independent gold standard instrumentation, and evaluate the systematic error of the W.M. Keck XROMM Facility’s biplanar videoradiography system using both marker-based and markerless tracking algorithms under static and dynamic motion conditions. A polycarbonate flag embedded with 12 radio-opaque markers was used to evaluate the systematic error of the marker-based tracking algorithm. Three human cadaveric bones (distal femur, distal radius, and distal ulna) were used to evaluate the systematic error of the markerless tracking algorithm. The systematic error was evaluated by comparing motions to independent gold standard instrumentation. Static motions were compared to high accuracy linear and rotary stages while dynamic motions were compared to a high accuracy angular displacement transducer. Marker-based tracking was shown to effectively track motion to within 0.1 mm and 0.1 deg under static and dynamic conditions. Furthermore, the presented results indicate that markerless tracking can be used to effectively track rapid bone motions to within 0.15 deg for the distal aspects of the femur, radius, and ulna. Both marker-based and markerless tracking techniques were in excellent agreement with the gold standard instrumentation for both static and dynamic testing protocols. Future research will employ these techniques to quantify in vivo joint motion for high-speed upper and lower extremity impacts such as jumping, landing, and hammering.
Simulation and experimental study of ArF 193 nm laser lift-off AlGaN/GaN high electron mobility transistors
Authors: Kang T. S. , Wang X. T. , Lo C. F. , Ren F. , Pearton S. J. , Laboutin O. , Cao Yu , Johnson J. W. , Kim Jihyun
Published: December 2011

A finite element simulation was used to estimate the temperature distributions within AlGaN/GaN high electron mobility transistors (HEMTs) during the laser lift-off process. The time-dependent simulation showed that a thin layer of GaN at the GaN/sapphire interface was heated up to around 1600 K in less than 25 ns by a pulsed laser exposure with a duration of 25 ns and a fluence of 800 mJ/cm2 to decompose this GaN layer into Ga and nitrogen. Experimentally, there was a threshold fluence around 550 mJ/cm2, corresponding to 1300 K at the GaN/sapphire interface, for partially lifting off the HEMT structure from the sapphire. The simulated temperature at the GaN/sapphire interface with a fluence of 420 mJ/cm2 never reached above 1000 K, however, the HEMT structure was lifted-off by multiple laser exposures at this fluence. Therefore, instead of thermally induced decomposition, the lift-off mechanism could also be through the Ga–N bond breaking during the multiple lower-fluence high-energy 193 nm laser exposures.
Strain-balanced InAs/InAs1−xSbx type-II superlattices grown by molecular beam epitaxy on GaSb substrates
Authors: Steenbergen Elizabeth H. , Nunna Kalyan , Ouyang Lu , Ullrich Bruno , Huffaker Diana L. , Smith David J. , Zhang Yong-Hang
Published: December 2011

Strain-balanced InAs/InAs1−xSbx type-II superlattices (SLs) on GaSb substrates with 0.27 ≤ x ≤0.33 were grown by molecular beam epitaxy and demonstrated photoluminescence (PL) up to 11.1 μm. The calculated SL bandgap energies agree with the PL peaks to within 5 meV for long-wavelength infrared samples (9.5, 9.9, and 11.1 μm) and to within 9 meV for a mid-wavelength infrared sample (5.9 μm). X-ray diffraction measurements reveal average SL mismatches of less than 0.2%, and the PL full-width-at-half-maximums increase with the mismatch, confirming the importance of strain-balancing for material quality.
The association of workflow interruptions and hospital doctors' workload: a prospective observational study
Authors: Weigl M , Müller A , Vincent C , Angerer P , Sevdalis N
Published: December 2011

Background

Subjective workload in healthcare employees is suspected to be important for the performance and safety of healthcare delivery. This study investigates associations between workflow interruptions and hospital doctors' capability to manage their perceived workload in a safe and efficient manner.

Aim

To examine the relationship of observed workflow interruptions with hospital doctors' perceived workload during day clinical shifts.

Methods

A prospective study of 43 full shift observations with 29 doctors working in internal medicine and surgical specialties. Workflow interruptions were assessed via observation using a previously validated observation instrument. Doctors assessed their workload twice throughout their day shift using three items of the validated NASA-Task Load Index (NASA-TLX; mental demands, effort, frustration).

Results

Hospital doctors were on average disrupted 3.66 times per hour. Most frequent were interruptions by nursing staff, telephone/beeper interruptions and by fellow doctors. Senior doctors reported higher workload than their junior colleagues. Overall workflow interruptions were significantly related to doctors' workload (β=0.22; p=0.03). Further analyses revealed that doctors' workload was associated particularly with interruptions by nursing personnel (β=0.23; p=0.03).

Conclusions

Frequent workflow interruptions may be linked with increased workload in doctors. Healthcare environments need to be better designed to reduce unnecessary interruptions and distractions so that hospital doctors can manage clinical work efficiently and safely.
Diagnostic testing for the detection of feline retroviruses
Authors: Adam Fiona , Dandrieux Julien
Published: December 2011

Since the discovery of feline leukaemia virus (FeLV) in 1964 and feline immunodeficiency virus (FIV) in 1986, knowledge of viral epidemiology and disease pathogenesis has developed greatly. Diagnostic tests demonstrating antigen, whole virus and the presence of virus‐specific antibody titres have allowed the identification of retrovirus‐infected cats. More recently, molecular testing methods have been developed for use in the diagnosis of FIV and FeLV. This article discusses the commercial diagnostic tests available for the detection of these viruses and outlines how such tests may be applied in clinical practice.
Intranasal immunisation with Stx2B‐Tir‐Stx1B‐Zot protein leads to decreased shedding in goats after challenge with Escherichia coli O157:H7
Authors: Zhang X‐H. , He K‐W. , Zhao P‐D. , Ye Q. , Luan X‐T. , Yu Z‐Y. , Wen L‐B. , Ni Y‐X. , Li B. , Wang X‐M. , Guo R‐L. , Zhou J‐M. , Mao A‐H.
Published: December 2011

Ruminants are an important reservoir of Escherichia coli O157:H7. To reduce E coli O157:H7 excretion by these animals could play a key role in prevention and control of human infections. In the present study, the authors used 12 three‐month‐old goats to evaluate the efficacy of intranasal administration of the Stx2B‐Tir‐Stx1B‐Zot protein. These goats were inoculated on days 0 and 21 and infected with 1010 colony‐forming units (cfu) of E coli O157:H7 by oral inoculation on day 36. Faecal shedding was monitored daily for two weeks. All of six goats immunised with recombinant protein elicited significant Stx2b‐Tir‐Stx1b‐Zot‐specific serum IgG antibodies, and three of them also showed production of antigen‐specific IgA in faeces. The immunised goats showed much less shedding of E coli O157:H7 after challenge. These results demonstrate the potential for the use of Stx2B‐Tir‐Stx1B‐Zot protein in mucosal vaccine formulations to prevent colonisation and shedding of E coli O157:H7 in goats.
EMBEDDING FRACTIONAL QUANTUM HALL SOLITONS IN M-THEORY COMPACTIFICATIONS
Authors: BELHAJ A. , FAHSSI N.-E. , SAIDI E. H. , SEGUI A.
Published: December 2011

We engineer U(1)n Chern–Simons type theories describing fractional quantum Hall solitons (QHS) in 1 + 2 dimensions from M-theory compactified on eight-dimensional hyper-Kähler manifolds as target space of N = 4 sigma model. Based on M-theory/type IIA duality, the systems can be modeled by considering D6-branes wrapping intersecting Hirzebruch surfaces F0's arranged as ADE Dynkin Diagrams and interacting with higher-dimensional R-R gauge fields. In the case of finite Dynkin quivers, we recover well known values of the filling factor observed experimentally including Laughlin, Haldane and Jain series.
UNITARY MATRICES AND COMMUTATORS
Authors: HARDY Y. , STEEB W.-H.
Published: December 2011

Unitary matrices are the quantum gates in quantum computing. We study the question under which conditions is the commutator of two unitary matrices again a unitary matrix. We consider the general case and a complete solution for the 2 × 2 unitary matrices. We also consider Kronecker products and direct sums of unitary matrices.
OPTIMAL CONTROL REALIZATIONS OF LAGRANGIAN SYSTEMS WITH SYMMETRY
Authors: DELGADO-TÉLLEZ M. , IBORT A. , DE LA PEÑA T. RODRÍGUEZ
Published: December 2011

A new relation among a class of optimal control systems and Lagrangian systems with symmetry is discussed. It will be shown that a family of solutions of optimal control systems whose control equation are obtained by means of a group action are in correspondence with the solutions of a mechanical Lagrangian system with symmetry. This result also explains the equivalence of the class of Lagrangian systems with symmetry and optimal control problems discussed in [1, 2].

The explicit realization of this correspondence is obtained by a judicious use of Clebsch variables and Lin constraints, a technique originally developed to provide simple realizations of Lagrangian systems with symmetry. It is noteworthy to point out that this correspondence exchanges the role of state and control variables for control systems with the configuration and Clebsch variables for the corresponding Lagrangian system.

These results are illustrated with various simple applications.
Neutrons and Photons in Nondestructive Detection
Authors: Harmon J. F. , Wells D. P. , Hunt A. W.
Published: December 2011

Active, nondestructive interrogation with neutrons and photons has seen a renaissance in recent years, owing to a broad spectrum of important applications in security, nuclear nonproliferation, contraband detection and materials analysis. Active methods are of high interest for such applications because they provide at least an order of magnitude greater sensitivity than passive methods. Accelerator-based neutron and photon active methods exploit two important factors to attain greater sensitivity: these are (i) the control of interrogating beam properties such as directionality, energy, intensity, polarization and the temporal distribution of radiation; (ii) well-founded, low energy nuclear physics that yields distinct "signatures" for elemental and isotopic content. This review addresses accelerator-based neutron and photon nondestructive testing methods and issues when applied to modern and emerging wide-ranging challenges in nondestructive detection.
A CLT FOR INFORMATION-THEORETIC STATISTICS OF NON-CENTERED GRAM RANDOM MATRICES
Authors: HACHEM WALID , KHAROUF MALIKA , NAJIM JAMAL , SILVERSTEIN JACK W.
Published: December 2011

In this article, we study the fluctuations of the random variable: [Formula: see text] where [Formula: see text], as the dimensions of the matrices go to infinity at the same pace. Matrices Xn and An are respectively random and deterministic N × n matrices; matrices Dn and [Formula: see text] are deterministic and diagonal, with respective dimensions N × N and n × n; matrix Xn = (Xij) has centered, independent and identically distributed entries with unit variance, either real or complex.

We prove that when centered and properly rescaled, the random variable [Formula: see text] satisfies a Central Limit Theorem and has a Gaussian limit. The variance of [Formula: see text] depends on the moment [Formula: see text] of the variables Xij and also on its fourth cumulant [Formula: see text].

The main motivation comes from the field of wireless communications, where [Formula: see text] represents the mutual information of a multiple antenna radio channel. This article closely follows the companion article "A CLT for Information-theoretic statistics of Gram random matrices with a given variance profile", Ann. Appl. Probab. (2008) by Hachem et al., however the study of the fluctuations associated to non-centered large random matrices raises specific issues, which are addressed here.
Hypoxia transiently affects skeletal muscle hypertrophy in a functional overload model
Authors: Chaillou Thomas , Koulmann Nathalie , Simler Nadine , Meunier Adélie , Serrurier Bernard , Chapot Rachel , Peinnequin Andre , Beaudry Michèle , Bigard Xavier
Published: December 2011

Hypoxia induces a loss of skeletal muscle mass, but the signaling pathways and molecular mechanisms involved remain poorly understood. We hypothesized that hypoxia could impair skeletal muscle hypertrophy induced by functional overload (Ov). To test this hypothesis, plantaris muscles were overloaded during 5, 12, and 56 days in female rats exposed to hypobaric hypoxia (5,500 m), and then, we examined the responses of specific signaling pathways involved in protein synthesis (Akt/mTOR) and breakdown (atrogenes). Hypoxia minimized the Ov-induced hypertrophy at days 5 and 12 but did not affect the hypertrophic response measured at day 56. Hypoxia early reduced the phosphorylation levels of mTOR and its downstream targets P70S6K and rpS6, but it did not affect the phosphorylation levels of Akt and 4E-BP1, in Ov muscles. The role played by specific inhibitors of mTOR, such as AMPK and hypoxia-induced factors (i.e., REDD1 and BNIP-3) was studied. REDD1 protein levels were reduced by overload and were not affected by hypoxia in Ov muscles, whereas AMPK was not activated by hypoxia. Although hypoxia significantly increased BNIP-3 mRNA levels at day 5, protein levels remained unaffected. The mRNA levels of the two atrogenes MURF1 and MAFbx were early increased by hypoxia in Ov muscles. In conclusion, hypoxia induced a transient alteration of muscle growth in this hypertrophic model, at least partly due to a specific impairment of the mTOR/P70S6K pathway, independently of Akt, by an undefined mechanism, and increased transcript levels for MURF1 and MAFbx that could contribute to stimulate the proteasomal proteolysis.
H reflex and spinal excitability: methodological considerations
Authors: Grosprêtre Sidney , Martin Alain
Published: December 2011

The Hoffmann reflex has been the tool most commonly used in exercise studies to investigate modulations in spinal excitability. However, the evolution of electromyographic responses with the increase in stimulation intensity has rarely been assessed when the muscle is active. The purpose of this study was thus to identify that part of the recruitment curve at which the investigation of the Hoffmann reflex is the most reliable in assessing spinal excitability during muscle contraction. Two recruitment curves were determined from the soleus and the medialis gastrocnemius, in passive and active (50% of maximal isometric voluntary contraction) conditions. No differences were found between the H reflexes in the two conditions in the ascending part of the recruitment curves, while the intensity necessary to elicit the same percentage of maximal H wave was different in the descending part of the curve, up to the maximal M wave. We concluded that during motor tasks, changes in spinal excitability should be assessed by recording H responses in the ascending part of the curve, where modulations do not depend either on the background electrical activity of the muscle tested or on methodological considerations.
Active force perception depends on cerebellar function
Authors: Bhanpuri Nasir H. , Okamura Allison M. , Bastian Amy J.
Published: December 2011

Damage to the cerebellum causes characteristic movement abnormalities but is thought to have minimal impact on somatosensory perception. Traditional clinical assessments of patients with cerebellar lesions reveal no perceptual deficits despite the fact that the cerebellum receives substantial somatosensory information. Given that abnormalities have been reported in predicting the visual consequences of movement, we suspect that the cerebellum broadly participates in perception when motor output is required (i.e., active perception). Thus we hypothesize that cerebellar integrity is essential for somatosensory perception that requires motor activity, but not passive somatosensory perception. We compared the perceptual acuity of human cerebellar patients to that of healthy control subjects in several different somatosensory perception tasks with minimal visual information. We found that patients were worse at active force and stiffness discrimination but similar to control subjects with regard to passive cutaneous force detection, passive proprioceptive detection, and passive proprioceptive discrimination. Furthermore, the severity of movement symptoms as assessed by a clinical exam was positively correlated with impairment of active force perception. Notably, within the context of these perceptual tasks, control subjects and cerebellar patients displayed similar movement characteristics, and hence differing movement strategies are unlikely to underlie the differences in perception. Our results are consistent with the hypothesis that the cerebellum is vital to sensory prediction of self-generated movement and suggest a general role for the cerebellum in multiple forms of active perception.
Congenital Central Hypothyroidism due to a Homozygous Mutation in theTSHβSubunit Gene
Authors: Grünert Sarah Catharina , Schmidts Miriam , Pohlenz Joachim , Kopp Matthias Volkmar , Uhl Markus , Schwab Karl Otfried
Published: December 2011

Congenital central hypothyroidism (CCH) is a rare condition occurring in 1 : 20000 to 1 : 50000 newborns. As TSH plasma levels are low, CCH is usually not detected by TSH-based neonatal screening for hypothyroidism, and, as a result, diagnosis is often delayed putting affected children at risk for developmental delay and growth failure. We report on a girl with isolated central hypothyroidism due to a homozygous one-base pair deletion (T313del) in exon 3 of theTSHβsubunit gene. The molecular genetic and typical radiologic findings are discussed, and a systematic diagnostic workup for congenital central hypothyroidism is proposed. Physicians need to be aware of this rare condition to avoid diagnostic delay and to install prompt replacement therapy.
Tuberculous Meningitis: Diagnosis and Treatment Overview
Authors: Marx Grace E. , Chan Edward D.
Published: December 2011

Tuberculous meningitis (TBM) is the most common form of central nervous system tuberculosis (TB) and has very high morbidity and mortality. TBM is typically a subacute disease with symptoms that may persist for weeks before diagnosis. Characteristic cerebrospinal fluid (CSF) findings of TBM include a lymphocytic-predominant pleiocytosis, elevated protein, and low glucose. CSF acid-fast smear and culture have relatively low sensitivity but yield is increased with multiple, large volume samples. Nucleic acid amplification of the CSF by PCR is highly specific but suboptimal sensitivity precludes ruling out TBM with a negative test. Treatment for TBM should be initiated as soon as clinical suspicion is supported by initial CSF studies. Empiric treatment should include at least four first-line drugs, preferably isoniazid, rifampin, pyrazinamide, and streptomycin or ethambutol; the role of fluoroquinolones remains to be determined. Adjunctive treatment with corticosteroids has been shown to improve mortality with TBM. In HIV-positive individuals with TBM, important treatment considerations include drug interactions, development of immune reconstitution inflammatory syndrome, unclear benefit of adjunctive corticosteroids, and higher rates of drug-resistant TB. Testing the efficacy of second-line and new anti-TB drugs in animal models of experimental TBM is needed to help determine the optimal regimen for drug-resistant TB.
Genetics of Isolated Hypogonadotropic Hypogonadism: Role of GnRH Receptor and Other Genes
Authors: Beate Karges , Joseph Neulen , Nicolas de Roux , Wolfram Karges
Published: December 2011

Hypothalamic gonadotropin releasing hormone (GnRH) is a key player in normal puberty and sexual development and function. Genetic causes of isolated hypogonadotropic hypogonadism (IHH) have been identified during the recent years affecting the synthesis, secretion, or action of GnRH. Developmental defects of GnRH neurons and the olfactory bulb are associated with hyposmia, rarely associated with the clinical phenotypes of synkinesia, cleft palate, ear anomalies, or choanal atresia, and may be due to mutations of KAL1, FGFR1/FGF8, PROKR2/PROK2, or CHD7. Impaired GnRH secretion in normosmic patients with IHH may be caused by deficient hypothalamic GPR54/KISS1, TACR3/TAC3, and leptinR/leptin signalling or mutations within the GNRH1 gene itself. Normosmic IHH is predominantly caused by inactivating mutations in the pituitary GnRH receptor inducing GnRH resistance, while mutations of theβ-subunits of LH or FSH are very rare. Inheritance of GnRH deficiency may be oligogenic, explaining variable phenotypes. Future research should identify additional genes involved in the complex network of normal and disturbed puberty and reproduction.
DNA Optimization Threshold Autoregressive Prediction Model and Its Application in Ice Condition Time Series
Authors: Yang Xiao-Hua , Li Yu-Qi
Published: December 2011

There are many parameters which are very difficult to calibrate in the threshold autoregressive prediction model for nonlinear time series. The threshold value, autoregressive coefficients, and the delay time are key parameters in the threshold autoregressive prediction model. To improve prediction precision and reduce the uncertainties in the determination of the above parameters, a new DNA (deoxyribonucleic acid) optimization threshold autoregressive prediction model (DNAOTARPM) is proposed by combining threshold autoregressive method and DNA optimization method. The above optimal parameters are selected by minimizing objective function. Real ice condition time series at Bohai are taken to validate the new method. The prediction results indicate that the new method can choose the above optimal parameters in prediction process. Compared with improved genetic algorithm threshold autoregressive prediction model (IGATARPM) and standard genetic algorithm threshold autoregressive prediction model (SGATARPM), DNAOTARPM has higher precision and faster convergence speed for predicting nonlinear ice condition time series.