Highly Dispersive Spin Excitations in the Chain Cuprate Li2CuO2

We present an inelastic neutron scattering investigation of Li2CuO2 detecting the long sought quasi-1D magnetic excitations with a large dispersion along the CuO2-chains studied up to 25 meV. The total dispersion is governed by a surprisingly large ferromagnetic (FM) nearest-neighbor exchange integral J1=-228 K. An anomalous quartic dispersion near the zone center and a pronounced minimum near (0,0.11,0.5) r.l.u. (corresponding to a spiral excitation with a pitch angle about 41 degree point to the vicinity of a 3D FM-spiral critical point. The leading exchange couplings are obtained applying standard linear spin-wave theory. The 2nd neighbor inter-chain interaction suppresses a spiral state and drives the FM in-chain ordering below the Ne'el temperature. The obtained exchange parameters are in agreement with the results for a realistic five-band extended Hubbard Cu 3d O 2p model and L(S)DA+U predictions.Comment: 6 pages, 4 figures, submitted to Europhys. Let

Preoperative assessment of meningioma aggressiveness by Thallium-201 brain SPECT

Introduction: Meningioma is usually a benign brain tumor, but sometimes with aggressive course. The aim of this study was to assess the ability of 201Tl Brain SPECT to differentiate the pathologic grade of meningioma preoperatively. Methods: Thirty lesions in 28 patients were evaluated in this study. Early (20 minutes) and late (3 hours) brain SPECT images were performed and early uptake ratio (EUR), late uptake ratio (LUR) and retention index (RI) were calculated. All patients were operated and pathologic grade of tumors were defined according to World Health Organization grading system. Results: SPECT results were compared in different pathologic groups. Data analysis clarified no significant difference of EUR in benign and aggressive meningioma (P=0.2). However LUR and RI were significantly higher in aggressive tumors (P=0.001 and P=0.02, respectively). Conclusion: According to our data Tl-201 Brain SPECT with early and late imaging has 80 sensitivity and specificity to differentiate malignant from benign meningioma

Medium Optimization using Response Surface Methodology for High Cell Mass Production of Lactobacillus acidophilus

608-614Lactobacillus acidophilus belongs to probiotic microflora inhabiting human gut that provide beneficially enhances human health. Besides balancing the intestinal flora and inhibiting pathogenic microorganisms, the existence of L. acidophilus inside the intestine can restore gut flora following antibiotics treatments. However, usually microorganisms from lactic acid bacteria group are known as fastidious microorganism and naturally required complex nutrients to promote their cellular growth. Therefore, twelve reported cultivation media were screened for their capability to support cell growth of L. acidophilus. The most suitable medium was further optimized using response surface methodology (RSM) and Box-Behnken design to maximize cell growth of L.acidophilus. Using this statistical approach, about 2.5-fold increase in maximal cell dry weight was achieved (5.14 g L-1) compared to the original medium (2.05 g L-1).This increase was accompanied by a significant increase in cell growth rates as well. The new medium formulation composed of (g L-1): glucose, 50; yeast extract, 20.91; ammonium citrate, 3.42; citric acid, 0.5; KH2PO4, 1.5; MgSO4.7H2O, 0.4; MnSO4.7H2O, 0.05; sodium acetate, 1; tween 80, 1

Experimental Studies on the Effect of Antenna Orientations to the Performance of OFDM-based System

Software-defined radio (SDR) is an emerging and promising high re-configurable platform for rapid prototyping inreal environment applications. It offers both flexibility and low cost to facilitate the development process of agile communication system, such as Orthogonal Frequency Division Multiplexing (OFDM). Other than modulation and transmission technique like OFDM, antenna orientations play a significant importance in wireless communication. The availabililty of SDR platform like USRP has enabled the empirical evaluation of antenna orientation to the system performance. The performance has been evaluated in terms of throughput and packet error rate. The findings show the antenna orientation affect the system performance significantly

Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties

Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated sol–gel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cm− 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film

Transition from Knudsen to molecular diffusion in activity of absorbing irregular interfaces

We investigate through molecular dynamics the transition from Knudsen to molecular diffusion transport towards 2d absorbing interfaces with irregular geometry. Our results indicate that the length of the active zone decreases continuously with density from the Knudsen to the molecular diffusion regime. In the limit where molecular diffusion dominates, we find that this length approaches a constant value of the order of the system size, in agreement with theoretical predictions for Laplacian transport in irregular geometries. Finally, we show that all these features can be qualitatively described in terms of a simple random-walk model of the diffusion process.Comment: 4 pages, 4 figure

Study of factors influencing construction delays at rural area in Malaysia

Construction is one of an important industry which contributes to the economic growth in Malaysia. However, it has been revealed that 79.5 percent and 66.7 percent of the public and private projects were not completed within the time specified in the contracts out of 359 projects in Malaysia. Therefore, the purpose of this study is to investigate the delay factor caused project delay at rural area. A 5-points Likert scale questionnaire survey were answered by 111 respondents which having experience with rural construction project. The questionnaire data were analysed by using Relative Importance Index (RII). Five top factors were determined from this study based on their RII values which are improper construction method implemented by contractor, weather condition, difficulties in providing delivery to site, breakdown of site equipment, and poor qualification of contractor’s technical staffs

Impact of an interatrial shunt device on survival and heart failure hospitalization in patients with preserved ejection fraction

Aims: Impaired left ventricular diastolic function leading to elevated left atrial pressures, particularly during exertion, is a key driver of symptoms and outcomes in heart failure with preserved ejection fraction (HFpEF). Insertion of an interatrial shunt device (IASD) to reduce left atrial pressure in HFpEF has been shown to be associated with short‐term haemodynamic and symptomatic benefit. We aimed to investigate the potential effects of IASD placement on HFpEF survival and heart failure hospitalization (HFH). Methods and results: Heart failure with preserved ejection fraction patients participating in the Reduce Elevated Left Atrial Pressure in Patients with Heart Failure study (Corvia Medical) of an IASD were followed for a median duration of 739 days. The theoretical impact of IASD implantation on HFpEF mortality was investigated by comparing the observed survival of the study cohort with the survival predicted from baseline data using the Meta‐analysis Global Group in Chronic Heart Failure heart failure risk survival score. Baseline and post‐IASD implant parameters associated with HFH were also investigated. Based upon the individual baseline demographic and cardiovascular profile of the study cohort, the Meta‐analysis Global Group in Chronic Heart Failure score‐predicted mortality was 10.2/100 pt years. The observed mortality rate of the IASD‐treated cohort was 3.4/100 pt years, representing a 33% lower rate (P = 0.02). By Kaplan–Meier analysis, the observed survival in IASD patients was greater than predicted (P = 0.014). Baseline parameters were not predictive of future HFH events; however, poorer exercise tolerance and a higher workload‐corrected exercise pulmonary capillary wedge pressure at the 6 months post‐IASD study were associated with HFH. Conclusions: The current study suggests IASD implantation may be associated with a reduction in mortality in HFpEF. Large‐scale ongoing randomized studies are required to confirm the potential benefit of this therapy