Influence of Prewhirl Regulation by Inlet Guide Vanes on Cavitation Performance of a Centrifugal Pump

The influence of prewhirl regulation by inlet guide vanes (IGVs) on a centrifugal pump performance is investigated experimentally and numerically. The experimental results show that IGVs can obviously change the head and increase the efficiency of the tested centrifugal pump over a wide range of flow rates. Although the cavitation performance is degraded, the variation of the cavitation critical point is less than 0.5 m. Movement of the computed three-dimensional streamlines in suction pipe and impeller are analyzed in order to reveal the mechanism how the IGVs realize the prewhirl regulation. The calculated results show that the influence of IGVs on the cavitation performance of centrifugal pump is limited by a maximum total pressure drop of 1777 Pa, about 7.6% of the total pressure at the suction pipe inlet for a prewhirl angle of 24°

Dual effects of biochar and hyperaccumulator Solanum nigrum L. on the remediation of Cd-contaminated soil

Biochar was widely developed for the soil amendment and remediation of heavy metal contaminated soil. The Cd hyperaccumulator, Solanum nigrum L., has been paid much more attention with the wide application of phytoremediation. The effects of biochar on the growth and accumulation capacity of Solanum nigrum L. in Cd contaminated soil have not been explored so far. The objectives of this study were to explore the dual effects of biochar addition on available Cd in the soil and hyperaccumulation of Cd in Solanum nigrum L. under different Cd contaminated levels. The correlations of soil physicochemical and biochemical properties and Cd absorption of Solanum nigrum L. were analyzed after a 60-day pot experiment under three biochar doses (0%, 1% and 5%) and four Cd concentrations (0, 25, 50 and 100 mg kg−1). The availability of Cd obtained by DTPA extraction significantly decreased after biochar application (P = 0.003, P = 0.0001, P = 0.0001 under 1% biochar addition for 25, 50, and 100 mg kg−1 Cd concentrations, P = 0.0001, P = 0.0001, P = 0.0001 under 5% biochar addition for 25, 50, and 100 mg kg−1 Cd concentrations, n ≥ 3). The 1% biochar dose significantly increased leaf dry weight (P = 0.039, P = 0.002 for the Cd concentrations of 50 and 100 mg kg−1, n ≥ 3) compared with the control in higher Cd concentrations (50 and 100 100 mg kg−1). In the presence of biochar, the bioconcentration factor (BCF) increased under the Cd concentrations of 50 and 100 mg kg−1. The translocation factors (TF) decreased with the biochar doses under the Cd concentration of 100 mg kg−1. The dose of 5% biochar significantly increased the urease activity by 41.18% compared to the 1% biochar addition in the Cd contaminated soil of 50 mg kg−1 concentration. The activities of acid phosphatase were inhibited by 1% biochar dose in all the Cd contaminated soils. The dry weight of the root of Solanum nigrum L. was significantly negatively correlated with acid phosphatase activity and BCF, respectively, indicating acid phosphatase in the rhizosphere soil of Solanum nigrum L. were repressed by Cd toxicity despite of biochar amendment. Biochar had no negative effect on Cd accumulation ability of Solanum nigrum L. Two-way ANOVA analysis showed that both biochar and Cd significantly affected the height of Solanum nigrum L. and the dry weight of leaf and stem. This study implied that biochar addition does not limit the absorption of hyperaccumulator Solanum nigrum L. in the remediation of Cd-contaminated soil. This study implied that the simultaneous application of biochar and hyperccumulator Solanum nigrum L. is promising during the remediation of Cd-contaminated soil

Metabolomics-Based Identification of Bleached Shellac in Liquid Fruit Wax

The purpose of this study was to identify whether liquid fruit waxes could be added with bleached shellac. The compounds of bleached shellac from different sources were analyzed by targeted metabolomics based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) combined with liquid chromatography with evaporative light scattering detection. Twelve target compounds were selected by multivariate statistical analysis including unsupervised principal component analysis (PCA) and supervised partial least squares discriminant analysis (PLS-DA). According to variable importance in the projection (VIP) value, five differential compounds and seven shared compounds were identified. Finally, the viability of this method in the detection of commercial liquid fruit wax products was verified using the shared compounds as biomarkers. These results showed that chromatography combined with mass spectrometry can identify whether bleached shellac could be added in liquid fruit wax

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Structural Repertoire of HIV-1-Neutralizing Antibodies Targeting the CD4 Supersite in 14 Donors

The site on the HIV-1 gp120 glycoprotein that binds the CD4 receptor is recognized by broadly reactive antibodies, several of which neutralize over 90% of HIV-1 strains. To understand how antibodies achieve such neutralization, we isolated CD4-binding-site (CD4bs) antibodies and analyzed 16 co-crystal structures –8 determined here– of CD4bs antibodies from 14 donors. The 16 antibodies segregated by recognition mode and developmental ontogeny into two types: CDR H3-dominated and VH-gene-restricted. Both could achieve greater than 80% neutralization breadth, and both could develop in the same donor. Although paratope chemistries differed, all 16 gp120-CD4bs antibody complexes showed geometric similarity, with antibody-neutralization breadth correlating with antibody-angle of approach relative to the most effective antibody of each type. The repertoire for effective recognition of the CD4 supersite thus comprises antibodies with distinct paratopes arrayed about two optimal geometric orientations, one achieved by CDR H3 ontogenies and the other achieved by VH-gene-restricted ontogenies

Influence of Tip Clearance on Pressure Fluctuation in Low Specific Speed Mixed-Flow Pump Passage

To explore the influence of tip clearance on pressure fluctuation in a low specific speed mixed-flow pump, tip clearances δ of 0.25 mm, 0.75 mm and 1.00 mm, along with no tip clearance, were selected. The reliability of the simulation was verified by comparison with the experimental data of external characteristics and fluctuation in the guide vane passage. Through ANSYS-CFX, MATLAB code and fast Fourier transform (FFT) algorithm, pressure fluctuation characteristics in this pump were obtained. The results show that pressure fluctuation exists in all conditions due to the rotor-stator interaction. Under the no tip clearance and tip clearance conditions, the maximum fluctuation value was located near the guide inlet and impeller outlet, respectively. Clearance leakage had less influence on pressure fluctuation at the impeller inlet and central regions within a certain range of the clearance; beyond this range, fluctuations in the whole flow passage increased significantly, while the clearance variation had less effect on fluctuation in the guide vane. When the tip clearance value was 1.00 mm, pressure fluctuation of the shroud at the impeller inlet section suddenly increases, which was closely related to the obvious leakage vortexes and a larger low pressure area