[Study on Chemical Constituents of Petroleum Ether Fraction from Rubus alceaefolius].

OBJECTIVE: To investigate the chemical constituents of Rubus alceaefolius. METHODS: Nine compounds were isolated and purified from the petroleum ether extract of 95% alcohol extract of Rubus alceaefolius by repeated column chromatography on silica, Sephadex LH-20 and structurally identified by spectral analysis. RESULTS: The compounds were identified as chrysophanol(1), physcion (2), ß-sitosterol(3), 3-oxotirucalla-7, 24-dien-21-oic acid(4), myricadiol(5), 19-α-hydroxy-3-acetyl-ursolic acid(6), N-benzoylphenylalaninyl-N-benzoylphenylalaninate(7), aurantiamide acetate(8) and euscaphic acid(9). CONCLUSION: Compounds land 4~8 are isolated from this plant for the first time, and compounds 4 - 8 are found in plants of Rubus genus for the first time.

A simple strategy for the generation of multi-copy Pichia pastoris with the efficient expression of mannanase.

Pichia pastoris expression system was widely used for producing heterologous proteins. Some researches revealed that the increase in the copy number could improve the expression of foreign genes in P. pastoris. Hundreds or thousands of antibiotic-resistance recombinants need to be screened because the frequency of multiple gene insertion events is very low in P. pastoris. The traditional method of constructing multi-copy gene is complicated, tedious, and full of randomness. Here, we developed a rapid method for constructing multi-copy Pichia expression vectors harboring mannanase gene. The developed strategy is easy to manipulate genetically and can precisely generate plasmids with a certain copy number of heterologous gene. The average mannanase activities of recombinants randomly chosen from two-, four-, and six-copy recombinant libraries were 1.7-, 2.2-, and 1.3-folds, respectively, of that from single-copy recombinant library. The result revealed that the strategy could effectively improve the expression of foreign proteins in P. pastoris.

Screening of multi-copy mannanase recombinants of Pichia pastoris based on colony size.

Pichia pastoris pGAP (glyceraldehyde dehydrogenase promoter) expression system was widely used for the expression and production of heterologous proteins. Screening multi-copy recombinants was an effective strategy to improve the heterologous protein production in P. pastoris. Because multiple gene insertion events occurred with a low frequency, hundreds to thousands of antibiotic-resistance recombinants need to be screened. The common way of improving screening efficiency was to increase antibiotic concentration in screening plates. Here we developed a screening method by selecting small colonies from low-concentration antibiotic screening plates. This strategy greatly improved the probability of obtaining multi-copy mannanase gene (man) recombinants and it could replace the common strategy by increasing antibiotic concentration in screening plates. The further study in liquid shake flask cultures revealed that cell concentrations, growth rates and substrate consumption rates of recombinants gradually decreased with the increase in man copy number. This indicated that such a screening strategy was effective to screen multi-copy recombinants based on colony size.

[Chemical constituents from roots of Rubus parvifolius].

OBJECTIVE: To investigate the chemical constituents from the roots of Rubus parvifolius. METHODS: The chemical constituents were isolated by silica gel column chromatography, Sephadex LH-20, as well as preparative high performance liquid chromatography. Their structures were identified on the basis of physicochemical properties and NMR analysis. RESULTS: Six comounds were isolated and identified as 3-O-Acetyl-11α, 12α-epoxy-oleanan-28,ß-olide( I ) ,3-O-Acetyl-pomolic acid( II ), Ursolic acid( Ill),Ursolic acid acetate (1V ), Euscaphic acid ( V) and ß-Sitosterol ( VI). CONCLUSION: Compounds I , II and IV are isolated from Rubus parvifolius for the first time.

Anisotropic strain enhanced hydrogen solubility in bcc metals: the independence on the sign of strain.

When an impurity is doped in a solid, it inevitably induces a local stress, tending to expand or contract the lattice. Consequently, strain can be applied to change the solubility of impurity in a solid. Generally, the solubility responds to strain "monotonically," increasing (decreasing) with the tensile (compressive) strain if the impurity induces a compressive stress or vice versa. Using first-principles calculations, however, we discovered that the H solubility can be enhanced by anisotropic strain in some bcc metals, almost independent of the sign of strain. This anomalous behavior is found to be caused by a continuous change of H location induced by anisotropic strain. Our finding suggests a cascading effect of H bubble formation in bcc metals: the H solution leads to H bubble formation that induces anisotropic strain that in turn enhances H solubility to further facilitate bubble growth.

[Comparative study on the content of chlorogenic acid in Solanum torvum from different origin, different harvest time and different part].

OBJECTIVE: To develop a HPLC method for determination of chlorogenic acid in Solanum torvum and provide a scientific basis for evaluating the quality and reasonable utilization of the herb. METHODS: HPLC was used to quantitatively determine the chlorogenic acid content in Solanum torvum from different origin, different harvest time and different part. The assay was performed on a Agela Promosil C18 (4.6 mm x 250 mm, 5 microm) column and eluted with a mobile phase consisted of acetonitrile -0.1% phosphoric acid solution at a flow rate of 1.0 ml/min. The column temperature was set at 35 degrees C. The detection wavelength was 327 nm. RESULTS: The calibration curve was linear within the range of 0.1000 - 200.0 microg/mL (r = 0.9999). The average recoveries were 99.8% (RSD = 0.71%). The contents of chlorogenic acid in Solanum torvum were different from different origin, different harvest time and different part. CONCLUSION: The method is reliable, accurate and specific. It can be used for quality control of Solanum torvum and reasonable utilization of the herb.

Clinical presentation, biochemical profile, and HLA haplotype frequency of celiac disease among adults in Northwest China.

OBJECTIVE: To evaluate the clinical characteristics, biochemical parameters and the distribution of HLA-DQ genotypes among adult patients with celiac disease (CD) in Northwest China. METHODS: This cross-sectional study retrospectively collected clinical, biochemical, and HLA-DQ genotype of patients with CD from a tertiary hospital in Xinjiang Uygur Autonomous Region, China between March 2016 and December 2021. Small intestinal biopsy and serum-specific antibodies were used to diagnose CD. RESULTS: Of the 102 CD patients, 63.7% were women (female: male = 1.76:1), and the mean age was 47.3 ± 14.7 years at diagnosis. Common gastrointestinal symptoms included abdominal pain (50.0%), diarrhea (39.2%), and abdominal distension (24.5%). While common extraintestinal manifestations were anemia (48.0%), osteopenia or osteoporosis (36.3%), and fatigue (35.3%). Approximately 34.3% of patients with CD had comorbidities, with the most common being thyroid diseases (18.6%). Biochemical profiles showed lower hemoglobin, higher platelet count, and 25-hydroxyvitamin D (25[OH]D) deficiency. HLA-DQ2/DQ8 was detected among all 53 patients who underwent genotype testing; the frequency of the HLA-DQ2.5, DQ2.2, and DQ8 haplotypes was 71.7%, 24.5%, and 3.8%, respectively. CONCLUSIONS: CD was more common among women. Clinical manifestations include primarily gastrointestinal symptoms, but extraintestinal manifestations were not uncommon. Lower hemoglobin level, higher platelet count, and 25[OH]D deficiency are the main biochemical manifestations. The HLA-DQ2.5 and DQ2.2 haplotypes are the most common genotypes in CD.

Synthesis, structure, and magnetic properties of three 1D chain complexes based on high-spin metal-cyanide clusters: [Mn(III)6M(III)] (M = Cr, Fe, Co).

On the basis of high-spin metal-cyanide clusters of Mn(III)(6)M(III) (M = Cr, Fe, Co), three one-dimensional (1D) chain complexes, [Mn(salen)](6)[Cr(CN)(6)](2)·6CH(3)OH·H(2)O (1), [Mn(5-CH(3))salen)](6)[Fe(CN)(6)](2)·2CH(3)CN·10H(2)O (2), and [Mn(5-CH(3))salen)](6)[Co(CN)(6)](2)·2CH(3)CN·10H(2)O (3) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized and characterized structurally as well as magnetically. Complexes 2 and 3 are isomorphic but slightly different from complex 1. All three complexes contain a 1D chain structure which is comprised of alternating high-spin metal-cyanide clusters of [Mn(6)M](3+) and a bridging group [M(CN)(6)](3-) in the trans mode. Furthermore, the three complexes all exhibit extended 3D supramolecular networks originating from short intermolecular contacts. Magnetic investigation indicates that the coupling mechanisms are intrachain antiferromagnetic interactions for 1 and ferromagnetic interactions for 2, respectively. Complex 3 is a magnetic dilute system due to the diamagnetic nature of Co(III). Further magnetic investigations show that complexes 1 and 2 are dominated by the 3D antiferromagnetic ordering with T(N) = 7.2 K for 1 and 9.5 K for 2. It is worth noting that the weak frequency-dependent phenomenon of AC susceptibilities was observed in the low-temperature region in both 1 and 2, suggesting the presence of slow magnetic relaxations.

Hybrid on-line optimal control strategy for producing α-amylase by Bacillus subtilis.

The combined effect of macronutrients in the extraction medium on α-amylase produced by Bacillus subtilis were studied by using response surface methodology in shaken flask cultures. The production of amylase was significantly affected by the interaction between wheat bran and the cotton seed extract in the extraction medium and by the interaction between the cotton seed extract and starch. The optimal combination in the extraction medium for maximum α-amylase production was determined as 10.80 g·L⁻¹ of wheat bran, 9.90 g·L⁻¹ of cotton seed extract, 0.5 g·L⁻¹ of starch, 2.0 g·L⁻¹ of yeast extract, 5.00 g·L⁻¹ of NaCl and 2.00 g·L⁻¹ of CaCl2. A 12.55-fold increase of enzyme activity was recorded in the optimized medium compared to the result acquired in a minimum essential medium. The optimized medium was used to compare different cultivation strategies in fermenters. The pH-stat strategy for reducing cellular stress response and the substrate concentration-stat strategy for reducing substrate inhibition were independently investigated. The temperature-limited strategy has been proposed to solve the proteolytic digestion problem, although the high-pressure strategy resulted in high productivity. A hybrid strategy simultaneously controlling pH, temperature, substrate concentration and pO2 was finally investigated to enhance the efficiency of the process. This hybrid strategy resulted in high activity of α-amylase, increasing the productivity almost three-fold as compared to an ordinary fed-batch culture.

Optimisation of the Conversion and Extraction of Arctigenin From Fructus arctii Into Arctiin Using Fungi.

Fructus arctii is commonly used in Chinese medicine, and arctiin and arctigenin are its main active ingredients. Arctiin has low bioavailability in the human body and needs to be converted into arctigenin by intestinal microbes before it can be absorbed into the blood. Arctigenin has antiviral, anti-inflammatory, and anti-tumour effects and its development has important value. In this study, we used external microbial fermentation with Aspergillus awamori and Trichoderma reesei to process and convert arctiin from F. arctii powder into arctigenin, hence increasing its bioavailability. We developed a fermentation process by optimising the carbon and nitrogen source/ratio, fermentation time, pH, liquid volume, inoculation volume, and substrate solid-liquid ratio. This allowed for an arctiin conversion rate of 99.84%, and the dissolution rate of the final product was 95.74%, with a loss rate as low as 4.26%. After the fermentation of F. arctii powder, the average yield of arctigenin is 19.51 mg/g. Crude fermented F. arctii extract was purified by silica gel column chromatography, and we observed an arctigenin purity of 99.33%. Our technique effectively converts arctiin and extracts arctigenin from F. arctii and provides a solid basis for further development and industrialisation.

Eicosanuclear cluster [Cu(13)W(7)] of copper-octacyanotungstate bimetallic assembly: synthesis, structure, and magnetic properties.

Octacyanotungstate(V) reacts with Cu(NO(3))(2).2H(2)O and 1,4,7-trimethyl-1,4,7-triazacyclononane in methanol, resulting in an eicosanuclear cluster [Cu(13)W(7)], which shows a diamondoid shape with a Tolkowsky cut and bears intracluster ferromagnetic coupling.

Strain Dependence of Energetics and Kinetics of Vacancy in Tungsten.

We investigate the influence of hydrostatic/biaxial strain on the formation, migration, and clustering of vacancy in tungsten (W) using a first-principles method, and show that the vacancy behaviors are strongly dependent on the strain. Both a monovacancy formation energy and a divacancy binding energy decrease with the increasing of compressive hydrostatic/biaxial strain, but increase with the increasing of tensile strain. Specifically, the binding energy of divacancy changes from negative to positive when the hydrostatic (biaxial) tensile strain is larger than 1.5% (2%). These results indicate that the compressive strain will facilitate the formation of monovacancy in W, while the tensile strain will enhance the attraction between vacancies. This can be attributed to the redistribution of electronic states of W atoms surrounding vacancy. Furthermore, although the migration energy of the monovacancy also exhibits a monotonic linear dependence on the hydrostatic strain, it shows a parabola with an opening down under the biaxial strain. Namely, the vacancy mobility will always be promoted by biaxial strain in W, almost independent of the sign of strain. Such unexpected anisotropic strain-enhanced vacancy mobility originates from the Poisson effect. On the basis of the first-principles results, the nucleation of vacancy clusters in strained W is further determined with the object kinetic Monte Carlo simulations. It is found that the formation time of tri-vacancy decrease significantly with the increasing of tensile strain, while the vacancy clusters are not observed in compressively strained W, indicating that the tensile strain can enhance the formation of voids. Our results provide a good reference for understanding the vacancy behaviors in W.

Application of real-time PCR to monitor population dynamics of defined mixed cultures of moderate thermophiles involved in bioleaching of chalcopyrite.

To compare oxidative dissolution rates of chalcopyrite by different consortia of moderately thermophilic acidophiles, various defined mixed cultures of three bacteria Acidithiobacillus caldus s2, Leptospirillum ferriphilum YSK, and Sulfobacillus sp. LN and one archaeon Ferroplasma thermophilum L1 were studied in batch shake flask cultures incubated at 45 degrees C. Chalcopyrite dissolution was determined by measuring variations of soluble copper, ferric iron, and pH. Microbial population dynamics involved in bioleaching process were monitored using real-time quantitative polymerase chain reaction (PCR) technology. The complex consortia containing both chemoautotrophic (L. ferriphilum and At. caldus) and chemomixotrophic (Sulfobacillus LN and F. thermophilum) moderate thermophiles were found to be the most efficient in all of those tested. Mutualistic interactions between physiologically distinct moderately thermophilic acidophiles, involving transformations of iron and sulfur and transfer of organic compound, were considered to play a critical role in promoting chalcopyrite dissolution. The real-time PCR assay was reliable to analyze population dynamics of moderate thermophiles in bioleaching systems, and the analysis results were consistent with physiological characteristics of these strains.

First-principles characterization of the anisotropy of theoretical strength and the stress-strain relation for a TiAl intermetallic compound.

We perform first-principles computational tensile and compressive tests (FPCTT and FPCCT) to investigate the intrinsic bonding and mechanical properties of a γ-TiAl intermetallic compound (L 1(0) structure) using a first-principles total energy method. We found that the stress-strain relations and the corresponding theoretical tensile strengths exhibit strong anisotropy in the [001], [100] and [110] crystalline directions, originating from the structural anisotropy of γ-TiAl. Thus, γ-TiAl is a representative intermetallic compound that includes three totally different stress-strain modes. We demonstrate that all the structure transitions in the FPCTT and FPCCT result from the breakage or formation of bonds, and this can be generalized to all the structural transitions. Furthermore, based on the calculations we qualitatively show that the Ti-Al bond should be stronger than the Ti-Ti bond in γ-TiAl. Our results provide a useful reference for understanding the intrinsic bonding and mechanical properties of γ-TiAl as a high-temperature structural material.

Analysis of several heavy metals in wild edible mushrooms from regions of China.

The metal (Cu, Ni, Cd, Hg, As, Pb) contents in wild edible mushrooms collected from three different sites in China were determined by atomic absorption spectrometry and atomic fluorescence spectrometry. All element concentrations were determined on a dry weight basis. A total of 11 species was studied, five being from the urban area and six from rural areas in China. The As content ranged from 0.44 to 1.48 mg/kg. The highest As content was seen in Macrolepiota crustosa from the urban area, and the lowest in Russula virescens from rural areas. A high Ni concentration (1.35 mg/kg) was found in Calvatia craniiformis from the urban area. The lowest Ni level was 0.11 mg/kg, for the species R. virescens and Cantharellus cibarius. The Cu content ranged from 39.0 to 181.5 mg/kg. The highest Cu content was seen in Agaricus silvaticus and the lowest in C. cibarius. The Pb content ranged from 1.9 to 10.8 mg/kg. The highest Pb value was found in C. craniiformis. The Cd content ranged from 0.4 to 91.8 mg/kg. The highest Cd value was found in M. crustosa. The Hg content ranged from 0.28 to 3.92 mg/kg. The highest Hg level was found in Agaricus species. The levels of the heavy metals Cd, Pb, and Hg in the studied mushroom species from urban area can be considered high. The metal-to-metal correlation analysis supported they were the same source of contamination. High automobile traffic was identified as the most likely source of the contamination. Based upon the present safety standards, consumption of those mushrooms that grow in the polluted urban area should be avoided.

[Effect of sandblasting combined with femtosecond laser-etching on surface physicochemical properties of pure titanium].

PURPOSE: The aim of this study was to generate periodic microstructures on pure titanium surface by femtosecond laser-etching after sandblasting, and to assess the physicochemical properties of its surface. METHODS: Twelve pure titanium discs with diameter of 10 mm and thickness of 4 mm were used and divided into 3 groups according to different surface treatment methods: group S (sandblasting surface), group SA (sandblasting surface with acid-etching), and group SL (sandblasting surface with femtosecond laser-etching). Scanning electron microscopy (SEM) was used to observe the surface morphology. X-ray energy spectrum(EDS) was used to observe the surface chemical compositions. Three dimensional surface topography and surface roughness were evaluated by laser scanning confocal microscope (CLSM). The static contact angle was detected by high temperature wetting angle measuring instrument. SPSS19.0 software package was used for statistical analysis. RESULTS: SEM and CLSM showed well-distributed periodic and cyclic microstructure which formed second-order roughness composite structure in group SL. EDS analysis showed that the Al element on SL surface decreased (group SL 4.37%group SA 0.32>group S 0). Surface roughness analysis showed that surface roughness significantly increased in group SL [group SL (7.33±0.38)µm>group SA (1.08±0.12)µm>group S (1.05±0.14)µm](P<0.001). Static contact angle analysis showed that the static contact angle of surface was significantly reduced in group SL [group SL (34.4±2.5)°

A charge-transfer salt, 3,5-dimethyl-1-(4-nitro-benz-yl)pyridinium 7,7,8,8-tetra-cyano-quinodimethane.

In the title salt, C(14)H(15)N(2)O(2) (+)·C(12)H(4)N(4) (-), the asymmetric unit contains one cation and one anion. C-H⋯N and C-H⋯N and C-H⋯O hydrogen bonds and π-π stacking inter-actions (inter-planar distance 3.845 Å) are found in the crystal structure.

[Bacterial diversity analysis of moderately thermophilic microflora enriched by different energy sources].

Bacterial biodiversities of three moderately thermophilic bioleaching microfloras grown at 50 degrees C on media with pyrite, chalcopyrite, and pure ferrous iron supplemented with sulfur as energy sources were investigated respectively. The 16S rRNA genes of the microorganisms in the cultures flasks were PCR amplified and cloned to identify the bacterial species by comparative sequence analysis, the structural differences of microfloras enriched by different energy sources were compared. A total of 303 clones were recovered and evaluated by restriction fragment length polymorphism (RFLP) analysis. Cluster analysis identified 29 unique RFLP patterns, and the inserted 16S rRNA genes sequences were determined and for phylogenetic analysis. Most of sequences obtained were similar (89.1%-99.7%) to the 16S rRNA gene sequences of the reported bioleaching microorganisms. The species identified from the flasks during bioleaching of pyrite, pure ferrous iron supplemented with sulfur, and chalcopyrite were closely related to Acidithiobacillus caldus, Sulfobacillus thermotolerans, Sulfobacillus thermosulfidooxidans, Leptospirillum ferriphilum, two uncultured forest soil bacterium clones and one uncultured proteobacterium clone. Among these bacteria, Acidithiobacillus caldus, Sulfobacillus thermotolerans and Leptospirillum ferriphilum were the dominant bacterial species. L. ferriphilum was the most dominant species in microfloras enriched in media with pyrite and ferrous iron supplemented with sulfur as energy sources, the abundance were 53.8% and 45.9% respectively. In the culture with chalcopyrite as energy sources, S. thermotolerans had the highest abundance of 70.1%.

[Determination of organochlorine pesticides redidues in traditional Chinese medicine including ginseng or American ginseng].

OBJECTIVE: To determine the residues of 19 organochlorine pesticides in traditional chinese medicine (TCM) including Radix ginseng or Radix panacis quinquefolii by capillary gas chromatograrhy. METHODS: The samples were extracted with ethyl acetate by ultrasonic, then cleaned up by a column packed with Florisil. The capillary column was DB-1701 (30 m x 0.32 m, 0.25 microm). The electron capture detector (ECD) was used. The pesticide residues were calculated by external standard method. RESULTS: The average recoveries and RSD ranged from 70.4% to 125.0% and 3.16% to 9.86%. CONCLUSION: The method is rapid, simple and accurate. It can be used to determine organochlorine pesticide residues in TCM.

Shear-coupled grain boundary migration assisted by unusual atomic shuffling.

Shear-coupled grain boundary (GB) migration can be an efficacious mechanism to accommodate plastic deformation when the grain size of polycrystalline materials goes small. Nevertheless, how this kind of GB motion comes into play at the atomic level has not been fully revealed. Here, we have investigated the shear-coupled migration (SCM) of typical [100] group symmetrical tilt GBs in bcc W using atomistic simulations. Depending on GB character, the SCM is found to proceed via dislocation slipping in the 〈100〉 or 〈110〉 mode with striking shear strength difference between them. We demonstrate that there exists an unusual atomic shuffling along the tilt axis, which greatly assists SCM to operate in the easier 〈110〉 mode instead of the 〈100〉 one. The present results highlight the significant role of GB character in the atomistic SCM process and contribute to the future design and fabrication of high-performance materials in GB engineering.