Numerical simulation of the near-wake flow field of a horizontal-axis wind turbine (HAWT) model

Using different tip speed ratios, the near-wake velocity field of a horizontal-axis wind turbine (HAWT) model was simulated. The distributions of the near-wake velocity behind the HAWT rotor are obtained. Furthermore, the development of the wake is shown. The resulting data can be used to identify and better understand the physical attributes of the complex flow field, as well as to aid in the accurate prediction of the HAWT’s performance. Calculations indicate that the axial flow downstream of the near-wake region displays obvious three-dimensional properties. The axial component of air flow velocity is larger than the tangential and radial velocity components. For wind turbines of varying heights, the velocity profiles for each component are similar in the near-wake region. Velocity loss exists downstream of the wind turbine’s near-wake region, decreasing with an increase in axial position downstream of the turbine. The rate of decrease in center velocity is largest at the near-wake region from the trailing edge of the blade to the position of twice the chord length downstream of the turbine. At the position of four times the chord length downstream, the lowest velocity is restored to over 70 % of the free incoming flow velocity

Application of meso-2,3-Dimercaptosuccinic Acid Self-assembled Gold Electrode for Voltammetric Determination of Copper

Fabrication and electrochemical characteristics of the meso-2,3-dimercaptosuccinic acid (DMSA) self-assembled monolayer modified gold electrode were described. The modified electrode exhibited increased sensitivity and selectivity for CuII compared to the bare gold electrode by stripping voltammetry and the peak current was proportional to the concentration of CuII in the range of 8.0 10–7 1.2 10–4 mol/L with the detection limit of 1.1 10–7 mol/L. The influence of coexistent substances was investigated and the modified electrode showed good selectivity for copper determination. The DMSA/Au electrode was applied for CuII determination in a tap water sample with satisfactory results, with the recovery in the range from 99.7 to 101.1 %

3,9-Dichloro-2,4,8,10-tetra­oxa-3,9-di­phosphaspiro­[5.5]undecane-3,9-dione

In the title compound, C5H8Cl2O6P2, the two six-membered rings display chair conformations. The P=O bond distances are 1.444 (2) and 1.446 (2) Å. Weak inter­molecular C—H⋯O hydrogen bonds are present in the crystal structure

Low temperature of radiofrequency ablation at the target sites can facilitate rapid progression of residual hepatic VX2 carcinoma

<p>Abstract</p> <p>Background</p> <p>Rapid progression of residual tumor after radiofrequency ablation (RFA) of hepatocellular carcinoma has been observed increasingly. However, its underlying mechanisms remain to be clarified. The present study was designed to determine whether low temperature of RFA at the target sites facilitates rapid progression of residual hepatic VX2 carcinoma and to clarify the possible underlying mechanisms.</p> <p>Methods</p> <p>The residual VX2 hepatoma model in rabbits was established by using RFA at 55, 70 and 85°C. Rabbits that were implanted with VX2 hepatoma but did not receive RFA acted as a control group. The relationship between rapid progression of residual hepatic VX2 carcinoma and low temperature of RFA at the target sites was carefully evaluated. A number of potential contributing molecular factors, such as proliferating cell nuclear antigen (PCNA), matrix metalloproteinase 9 (MMP-9), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and Interleukin-6 (IL-6) were measured.</p> <p>Results</p> <p>The focal tumor volume and lung metastases of RFA-treated rabbits increased significantly compared with the control group (<it>P </it>< 0.05), and the greatest changes were seen in the 55°C group (<it>P </it>< 0.05). Expression of PCNA, MMP-9, VEGF, HGF and IL-6 in tumor tissues increased significantly in the RFA-treated groups compared with the control group, and of the increases were greatest in the 55°C group (<it>P </it>< 0.05). These results were consistent with gross pathological observation. Tumor re-inoculation experiments confirmed that low temperature of RFA at the target sites facilitated rapid progression of residual hepatic VX2 carcinoma.</p> <p>Conclusions</p> <p>Insufficient RFA that is caused by low temperature at the target sites could be an important cause of rapid progression of residual hepatic VX2 carcinoma. Residual hepatic VX2 carcinoma could facilitate its rapid progression through inducing overexpression of several molecular factors, such as PCNA, MMP-9, VEGF, HGF and IL-6.</p

Disruption of zebrafish cyclin G-associated kinase (GAK) function impairs the expression of Notch-dependent genes during neurogenesis and causes defects in neuronal development

<p>Abstract</p> <p>Background</p> <p>The J-domain-containing protein auxilin, a critical regulator in clathrin-mediated transport, has been implicated in <it>Drosophila </it>Notch signaling. To ask if this role of auxilin is conserved and whether auxilin has additional roles in development, we have investigated the functions of auxilin orthologs in zebrafish.</p> <p>Results</p> <p>Like mammals, zebrafish has two distinct auxilin-like molecules, auxilin and cyclin <b>G-a</b>ssociated <b>k</b>inase (GAK), differing in their domain structures and expression patterns. Both zebrafish auxilin and GAK can functionally substitute for the <it>Drosophila </it>auxilin, suggesting that they have overlapping molecular functions. Still, they are not completely redundant, as morpholino-mediated knockdown of the ubiquitously expressed GAK alone can increase the specification of neuronal cells, a known Notch-dependent process, and decrease the expression of <it>Her4</it>, a Notch target gene. Furthermore, inhibition of GAK function caused an elevated level of apoptosis in neural tissues, resulting in severe degeneration of neural structures.</p> <p>Conclusion</p> <p>In support of the notion that endocytosis plays important roles in Notch signaling, inhibition of zebrafish GAK function affects embryonic neuronal cell specification and <it>Her4 </it>expression. In addition, our analysis suggests that zebrafish GAK has at least two functions during the development of neural tissues: an early Notch-dependent role in neuronal patterning and a late role in maintaining the survival of neural cells.</p

Aplikasi Image Thresholding Untuk Segmentasi Objek

Salah satu operasi di dalam analisis citra adalah segmentasi citra, yaitu memisahkan objek dari latar belakangnya atau dari objek lain yang tidak menjadi perhatian. Metode sementasi yang sederhana adalah dengan operasi pengambangan (thresholding). Operasi pengambangan menghasilkan citra biner, yang dalam hal ini objek yang diacu di-set berwarna putih sedangkan latar belakangnya di-set berwarna hitam (atau sebaliknya bergantung kasusnya). Makalah ini mempresentasikan penggunaan operasi pengambangan untuk melakukan segmentasi objek. Eksperimen dilakukan dengan menggunakan kakas MATLAB. Hasil eksperimen memperlihatkan bahwa pemilihan nilai ambang (threshold) yang tepat sangat menentukan keberhasilan segmentasi

Integrated traditional Chinese and western medicine for Menopausal syndrome: Meta-analysis of randomized controlled trials

Background: To critically assess the evidence of integrated Chinese and western medicine for treating  Menopausal syndrome (MPS).Methods and Materials: A search across the Chinese Biomedical Medicine (CBM), Chinese National Knowledge Infrastructure (CNKI), VIP database (VIP), Wangfang database (Wanfang), PubMed and the Cochrane Library databases was conducted (up to October 31st, 2013) in commonly used integrated Chinese and western medicine therapies for menopausal syndrome. A number of Randomized Controlled Trials (RCTs) evaluating the therapeutic efficacy of integrated Chinese and western medicine in patients with PPS were included. The quality of the included studies was evaluated and a meta-analysis was performed using the RevMan5.0 software.Results: Twelve RCTs with 1155 patients were evaluated in this review. The results of meta-analysis showed that the therapy of using integrated Chinese and western medicine was significantly superior to that of western medicine alone towards improving the efficacy, relieving the clinical symptoms and decreasing follicle-stimulating hormone (FSH）levels (P&lt;0.05), even though the effects of two treatments were the same in regulating the levels of luteinizing hormone (LH) and estradiol (E2).Conclusion: Compared to a regular treatment with western medicine alone, the therapeutic approach that utilizes integration of Chinese with western medicine can effectively improve the clinical efficacy and serum hormone levels in patients with menopausal syndrome. However, the evidence was not very strong due to the poor quality of the included studies.Key words: Integrated Traditional Chinese and Western Medicine, Menopausal Syndrome, Meta-analysi

A novel Brassica–rhizotron system to unravel the dynamic changes in root system architecture of oilseed rape under phosphorus deficiency

Background and Aims: An important adaptation of plants to phosphorus (P) deficiency is to alter root system architecture (RSA) to increase P acquisition from the soil, but soil-based observations of RSA are technically challenging, especially in mature plants. The aim of this study was to investigate the root development and RSA of oilseed rape (Brassica napus L.) under low and high soil P conditions during an entire growth cycle. Methods: A new large Brassica–rhizotron system (approx. 118-litre volume) was developed to study the RSA dynamics of B. napus ‘Zhongshuang11’ in soils, using top-soils supplemented with low P (LP) or high P (HP) for a full plant growth period. Total root length (TRL), root tip number (RTN), root length density (RLD), biomass and seed yield traits were measured. Key Results: TRL and RTN increased more rapidly in HP than LP plants from seedling to flowering stages. Both traits declined from flowering to silique stages, and then increased slightly in HP plants; in contrast, root senescence was observed in LP plants. RSA parameters measured from the polycarbonate plates were empirically consistent with analyses of excavated roots. Seed yield and shoot dry weights were closely associated positively with root dry weights, TRL, RLD and RTN at both HP and LP. Conclusions: The Brassica–rhizotron system is an effective method for soil-based root phenotyping across an entire growth cycle. Given that root senescence is likely to occur earlier under low P conditions, crop P deficiency is likely to affect late water and nitrogen uptake, which is critical for efficient resource use and optimal crop yields