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ObjectiveTo analyze the chemical structure of the interfering substance that affects the result of methamphetamine analysis in wastewater.MethodsA combination of GC-MS and liquid chromatography-quadrupole time-of-flight mass spectrometry （LC-QTOF-MS） was used to analyze the mass spectrum characteristics of the interfering substance that affects the result of methamphetamine analysis and to infer its possible structure. Liquid chromatography-triple quadrupole-mass spectrometry （LC-TQ-MS） was used to confirm the control material.ResultsUsing LC-QTOF-MS in positive electrospray ionization （ESI+） mode, the mass-to-charge ratio （m/z） of quasi-molecular ion in the MS1 mass spectrometry of interfering substance was identical to that of methamphetamine, indicating that the interfering substance was probably an isomer of methamphetamine. The MS2 mass spectra obtained at three collision energies of 15 V, 30 V and 45 V were highly similar to methamphetamine, suggesting that the interfering substance contained methylamino and benzyl groups. Further analysis using GC-MS in electron impact （EI） ionization mode showed that the base peak in the mass spectrum of the interfering substance was at m/z 44. The interfering substance was confirmed to be N-methyl-2-phenylpropan-1-amine by compared with the standard reference.ConclusionThe chemical structure of N-methyl-2-phenylpropan-1-amine is highly similar to methamphetamine, which is easy to cause interference for the detection of trace amounts of methamphetamine in wastewater using LC-TQ-MS. Therefore, in the actual analysis, the chromatographic retention time can be used to distinguish between N-methyl-2-phenylpropan-1-amine and methamphetamine.

Objective To observe the effect of pseudolaric acid B(PAB) on the proliferation and apoptosis of human diffuse large B-cell lymphoma cell line SU-DHL-4 possibly and to explore the potential mechanism through regulating miR-4282. Methods SU-DHL-4 cells were divided into control group, PAB-L group, PAB-M group, PAB-H group; According to liposome method, miR-NC and miR-4282 were transfected into the cells and were marked as miR-NC group, miR-4282 group; The anti-miR-NC, anti-miR-4282 were transfected into the cells,cultured with 20 μmol/L PAB, denoted as (PAB+anti-miR-NC)group and(PAB+anti-miR-4282)group. Cell pro- liferation was detected by CCK8 assay, and cell apoptosis was detected by flow cytometry. The expression of Ki-67,cleaved caspase-3, cleaved caspase-9 protein was detected by Western blot and miR-4282 expression was detected by RT-qPCR. Results Compared with the control group, Ki-67 protein expression in PAB-L group, PAB-M group, and PAB-H group was decreased while miR-4282 expression, and the apoptosis rate, cell inhibition rate, protein expression of cleaved caspase-3, cleaved caspase-9 were increased (P＜0.05). Compared with the miR-NC group, Ki-67 protein expression in miR-4282 group decreased, while miR-4282 expression, the apoptosis rate, cell inhibition rate, protein expression of cleaved caspase-3, cleaved caspase-9 were all increased (P＜0.05). Inhibition of miR-4282 expression reduced the effect of PAB on the proliferation and apoptosis of SU-DHL-4 cells. Conclusions PAB may inhibit the proliferation of human diffuse large B-cell lymphoma cell SU-DHL-4 and promote apoptosis through increased expression of miR-4282.

How to realize more reasonable noise addition in location differential privacy-preserving is a hot topic issue.However,adding the same amount of noise in different locations will result in the decrease of service availability and privacy preservation.To this end,a differentially private location privacy-preserving scheme with semantic location is examined in this paper,which can systematically solve the contradiction among privacy-preserving,service availability and time overhead.The proposed method firstly constructs the expected distance by employing the framework of geo-indistinguishability,then determines the sensitivity of different locations by using the privacy quality function and requirement function,and finally adds Laplace noise to different types of region at fine granularity according to the location sensitivity.Comprehensive simulation experiments are carried out on two public datasets,which compare the proposed scheme with the existing methods in terms of query success rate based on Bayesian attack,service availability based on expected distance quantization and time overhead.The experimental results demonstrate that the proposed scheme is feasible and effective,and obtains a better trade-offs among privacy preservation,service availability and time consuming.

The testing blocks of AlSi7MgTi alloy were prepared by selective laser melting (SLM) technique and T6 heat treatment using alloy powders fabricated by supersonic gas atomization equipment. The microstructure, phase composition, residual stress, and mechanical properties of as-built and T6 treated alloys were investigated by optical microscope,scanning electron microscope,X-ray diffractometer,Raman spectrometer and tensile tests, respectively. The results indicate that as-built alloy mainly consists of supersaturated α(Al) solid solution and Si phases. The microstructure characterized by layer-by-layer stacking and interlaced of "scale-like" melt pool, shows obvious anisotropy. In addition, Si phase exists in the form of cellular eutectic silicon, which is connected by blocky and fibrous eutectic silicon. The eutectic silicon near melt pool boundary is relatively thick, while it is smaller in interior of melt pool. T6 heat treatment promotes the precipitation of Si phases, and leads to the Ostwald coarsening of eutectic silicon. Meanwhile, the melt pool morphologies and cellular eutectic silicon structure are basically eliminated by T6 heat treatment. Additionally, the residual stress is significantly reduced after heat treatment. The tensile strength and yield strength of as-built alloy reach up to 420-430 MPa and 280-300 MPa respectively, with elongation of 5.1%-11.0%. However, the tensile strength of T6 heat treated alloy is reduced to about 360 MPa, and yield strength is almost equal to that of as-built alloy, while elongation increases to 15.2%-16.5%.

BACKGROUND Beijing is a typical geographical distribution area of selenium deficiency. However, some research results in recent years indicate that the soils in some areas reaches the level of selenium enrichment. It is important to study the characteristics of selenium distribution in these areas for the research of a selenium-rich environment in Beijing and the development of selenium-rich land resources. OBJECTIVES To discuss the characteristics of selenium content in soil and crops, the source of selenium and the relationship between selenium in soil and other elements such as carbon, iron and phosphorus, and to evaluate the safety of selenium-rich land. METHODS Samples of 1297 topsoil, 25 sets of corn and corresponding root soil and 15 rock samples were collected from an eco-conserving division of the Daqinghe River watershed. The content of selenium in these samples was determined by atomic fluorescence spectrometry. Methods of correlation analysis and multivariate statistical analysis and GIS technology were used to study the characteristics of selenium content in soil and crops, the source of selenium enrichment, and the relationship between soil selenium and other elements such as carbon, nitrogen, phosphorus and sulfur, and the safety of selenium-rich land was evaluated. RESULTS The results showed that the soil selenium content ranged from 0.055 to 0.465mg/kg and that the background value was 0.257mg/kg, which show selenium-rich characteristics. 360.4km2 selenium-rich land resources was identified. The selenium content of corn ranged from 0.028 to 0.70mg/kg, and the geometric mean was 0.20mg/kg. 80% of the corn samples were selenium-rich products. The selenium-rich soil and the selenium-rich crops had the same spatial distribution, which indicated that the soil was an important source of selenium in crops. CONCLUSIONS Geological background and soil parent material are the key control factors affecting the distribution of selenium-rich land resources. Dark rock series of fluvial deposition are a crucial source of selenium in soil. The overall environmental quality of selenium-rich land is clean and safe, and only 0.2% of the area (3.23km2) contains soil heavy metal (Cd, Hg, Pb) content, which exceeds the level of risk management control. Due to these findings, attention needs to be paid during selenium-rich land development.

BackgroundMarie Unna hereditary hypotrichosis (MUHH) is an autosomal dominant disorder characterised by coarse, wiry, twisted hair developed in early childhood and subsequent progressive hair loss. MUHH is a genetically heterogeneous disorder. No gene in 1p21.1-1q21.3 region responsible for MUHH has been identified.MethodsExome sequencing was performed on two affected subjects, who had normal vertex hair and modest alopecia, and one unaffected individual from a four-generation MUHH family of which our previous linkage study mapped the MUHH locus on chromosome 1p21.1-1q21.3.ResultsWe identified a missense mutation in EPS8L3 (NM_024526.3: exon2: c.22G->A:p.Ala8Thr) within 1p21.1-1q21.3. Sanger sequencing confirmed the cosegregation of this mutation with the disease phenotype in the family by demonstrating the presence of the heterozygous mutation in all the eight affected and absence in all the seven unaffected individuals. This mutation was found to be absent in 676 unrelated healthy controls and 781 patients of other disease from another unpublished project of our group.ConclusionsTaken together, our results suggest that EPS8L3 is a causative gene for MUHH, which was helpful for advancing us on understanding of the pathogenesis of MUHH. Our study also has further demonstrated the effectiveness of combining exome sequencing with linkage information for identifying Mendelian disease genes.

In this paper, we first discuss the boundedness of certain integral operator Tt on the normal weight general function space F(p, μ, s) in the unit ball Bn of ℂn. As an application of this operator, we prove that the Gleason's problem is solvable on F(p, μ, s). [ABSTRACT FROM AUTHOR]

The block samples of a Ni-based superalloy named GH4169 were prepared by laser melting deposited method using the corresponding GH4169 alloy powders,and then were heat treated with solution treatment followed by double aging.The microstructure and element segregation analysis of both as-deposited and heat treated samples were studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).The microhardness as well as tensile properties at room and elevated temperatures were tested.The results indicate that the microstructure of as-deposited sample mainly consists of columnar dendritic crystals that grow along with different directions.Grains are refined after solution and aging heat treatment,but remain dendritic crystals substructure inside.Compared with the as-deposited sample,the microhardness and tensile strength of the heat treated sample increase substantially,but the plasticity somewhat decreases.Nonetheless the tensile properties are superior to the standard values of forgings.The fracture surface exhibits ductile transcrystalline fracture mode.

Several variants of T4 lysozyme have been identified that sequester small organic ligands in cavities or clefts. To evaluate potential binding sites for non-polar molecules, we screened a number of hydrophobic large-to-small mutants for stabilization in the presence of benzene. In addition to Leu99-->Ala, binding was indicated for at least five other mutants. Variants Met102-->Ala and Leu133-->Gly, and a crevice mutant, Phe104-->Ala, were further characterized using X-ray crystallography and thermal denaturation. As predicted from the shape of the cavity in the benzene complex, mutant Leu133-->Gly also bound p-xylene. We attempted to enlarge the cavity of the Met102-->Ala mutant into a deep crevice through an additional substitution, but the double mutant failed to bind ligands because an adjacent helix rearranged into a non-helical structure, apparently due to the loss of packing interactions. In general, the protein structure contracted slightly to reduce the volume of the void created by truncating substitutions and expanded upon binding the non-polar ligand, with shifts similar to those resulting from the mutations.A polar molecule binding site was also created by truncating Arg95 to alanine. This creates a highly complementary buried polar environment that can be utilized as a specific "receptor" for a guanidinium ion. Our results suggest that creating a deficiency through truncating mutations of buried residues generates "binding potential" for ligands with characteristics similar to the deleted side-chain. Analysis of complex and apo crystal structures of binding and non-binding mutants suggests that ligand size and shape as well as protein flexibility and complementarity are all determinants of binding. Binding at non-polar sites is governed by hydrophobicity and steric interactions and is relatively permissive. Binding at a polar site is more restrictive and requires extensive complementarity between the ligand and the site.

The ZM5 magnesium alloy plates were welded by TIG welding method. The microstructural characteristics and mechanical properties of ZM5 magnesium alloy joint were studied by optical microscopy, microhardness and tensile testers. The results show that the TIG weld joint of ZM5 magnesium alloy is composed of heat affected zone, partially melted zone and weld metal. The heat affected zone is consisted of primary α-Mg phase and eutectic phase that is composed of eutectic α-Mg and eutectic β-Mg17Al12 phase and mainly precipitated at grain boundaries. In the partially melted zone, the eutectic phase is not only increasingly precipitated at grain boundaries, but also dispersed in grains, and the growth of the β-Mg17Al12 phase is obviously observed. The microstructure in the weld is the typical dendritic morphology. The dendrites are considered as primary α-Mg phase, and the interdendritic regions are α+β eutectic phase. The difference in the microstructure of the heat affected zone, partially melted zone and weld results in their various microhardness values, and leads to the smaller tensile strength and ductility in the ZM5 alloy weld joint than parent metal.