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The aim of this study was to determine the effect of particle size on the oxidation and flotation behavior of galena particles. Coarse (-0.074+0.038 mm), intermediate (-0.038+0.025 mm) and fine (-0.025 mm) galena particles were used in this study. Dissolution tests demonstrated that the amount of oxidation products increased with the decrease of particle sizes. The surface oxidization of galena was the greatest at pH 7.3, followed by pH 12 and 9, which were consist with the result of XPS. The microflotation results indicated that the effect of pH on the flotation recovery of galena enhanced with the reduction of particle sizes. The decreasing of particle sizes increases both the sorption rate of collector and the dissolution of galena, while the generation of hydrophilic product caused by dissolution is dominant, rendering the mineral hydrophilic. This study shows the differences in the surface oxidation and flotation behavior of different size fractions of galena particles. To promote the flotation recovery of the fine size fraction of galena particles, alleviating their oxidation is the key. [ABSTRACT FROM AUTHOR]

Effects of In, Ge, Fe substitution in the lattice of sphalerite on wettability were usually ignored, therefore the optimal flotation condition could be difficult to find due to lacking of sufficient theoretical study on water adsorption, resulting lower recoveries of different sphalerites. Adsorption of H2O on different sphalerite surfaces was studied using density functional theory (DFT) method. All computational models were built in a vacuum environment to eliminate the effects of oxygen and other factors. H2O molecule prefers to stay with ideal sphalerite, indium-beard sphalerite, germanium-beard sphalerite and marmatite surfaces rather than water. Compared with ideal sphalerite surface, Fe atom improves the hydrophilicity of surface, while In and Ge atoms reduce the hydrophilicity. [ABSTRACT FROM AUTHOR]

Naturally, most of the cassiterite co-exists with sparingly soluble calcite, which makes it difficult to be fully utilized. Due to the adsorption of calcium ions dissolved from calcite, surface properties of cassiterite and its floatability can be influenced. Adsorption tests show calcium ions can adsorb on cassiterite surface. In the presence of Ca2+, the zeta potentials of cassiterite shift to more positive values and the isoelectric point of cassiterite increases from pH 4.4 to pH 4.9. XPS results show that after calcium ions treatment, a strong calcium spectral peak at 347.65 eV is detected on the cassiterite surface and the chemical circumstance of oxygen atoms is changed. The presence of Ca2+ can significantly depressed the flotation behavior of cassiterite with salicylhydroxamic acid (SHA) as collector. Its recovery is decreased by 26.03% compared to that without Ca2+ at SHA dosage of 8.0×10-4 mol/dm3. When increasing SHA concentration to 9.0×10-4 mol/dm3 and above, the depression effect is partly compensated and the recovery rises by about 20%. Contact angle values of cassiterite measured by the bubble method correspond well to the flotation performance. Hence the depression mechanism of Ca2+ in cassiterite flotation can be interpreted in two aspects: 1) the consumption of SHA due to complexation reactions in pulp; 2) a decrease of effective adsorption site for SHA on cassiterite because of the adsorption of Ca2+. [ABSTRACT FROM AUTHOR]

The flotation behavior and adsorption mechanism of cassiterite using sodium lauroamphoacetate (SLA) as a collector were investigated by adsorption tests, micro-flotation tests, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis. Adsorption test results indicated that the adsorption of SLA on the cassiterite surface increased continually with the increase of SLA concentration. Micro-flotation test results demonstrated that SLA had a stronger collecting ability to cassiterite than salicylhydroxamic acid (SHA) and sodium oleate (NaOL) in the pH range of 2-12, and showed a higher selectivity in the separation of cassiterite-quartz than in cassiterite-clinochlore. The zeta potential measurement results indicated that the isoelectric point (IEP) of cassiterite minerals changed from pH 3.9 to 3.4, suggesting the adsorption of SLA on cassiterite surface. The FTIR spectra and XPS analysis further confirmed that SLA chemically adsorbed on cassiterite surface. [ABSTRACT FROM AUTHOR]

The interaction between sphalerite and pyrite was investigated by dissolution test, X-ray photoelectron spectroscopy (XPS), zeta potential measurement and density functional theory (DFT) calculation. Dissolution tests indicated that sphalerite dissolution was promoted due to the galvanic interaction between sphalerite and pyrite. The Zn2+ ion concentration increased with increasing pyrite content and dissolved time. XPS analysis results demonstrated that a new oxidation product was formed on the sphalerite surface in the presence of pyrite in a pulp. Zeta potential measurements showed that the isoelectric point of sphalerite increased from 3.3 to 5.4 due to galvanic interaction. DFT calculation results suggested that electron transfer from sphalerite to pyrite occurred when they contacted. The Zn 4s and S 3p states of sphalerite lost electrons. The Fe 4p and 4s of pyrite states obtained electrons, and Fe 3d and S 3s states lost a small number of electrons. The surface oxidation of sphalerite was promoted due to the interaction with pyrite, and the collectorless floatability of sphalerite decreased. [ABSTRACT FROM AUTHOR]

Pulsating high gradient magnetic separation (PHGMS) for removing trace amounts of iron impurities from a quartz ore was investigated using a lab-scale PHGMS separator, and its performance was further confirmed through a pilot-scale PHGMS separator. The results of this investigation indicated that PHGMS is effective for removing the iron impurities from the ore. By applying the lab-scale separator with a rod matrix of 1.5 mm diameter to the ore containing 0.063% Fe2O3, a concentrate assaying 0.0079% Fe2O3 with 89.82% iron removal rate was achieved through a two-step purification of PHGMS. It was found that the separation performance of this lab-scale separator was closely correlated with the wire diameter of matrix, pulsating frequency and background magnetic induction. Compared with the separation characteristics of PHGMS in beneficiating feebly magnetic metallic ores, it is clear that a much gentler pulsating intensity and a much higher background magnetic induction are both required to maintain a high iron removal rate. The comparison test of HIWGS further evidences the positive effect of pulsating energy in the high gradient magnetic separation. The purification performance of the lab-scale separator was well duplicated by the pilot-scale one, so that it was concluded that PHGMS provides an effective way for removing trace amounts of iron impurities from similar non-metallic ores. [ABSTRACT FROM AUTHOR]

Adsorption characteristics on hematite of caustic-digested starch by sodium hydroxide or potassium hydroxide were investigated through a series of tests, like adsorption tests, paste titration and zeta potentials measurement, scanning electron microscope measurement (SEM) and Fourier transform infrared spectroscopic analysis (FTIR) as well. An attempt was made in order to identify the possible effects of starch digested with alkali at different concentrations on its adsorption on mineral surfaces. All results pointed out that a different amount of carboxyl groups in the starch gel were harvested from alkalidigestion as a function of concentrations of sodium hydroxide or potassium hydroxide; more acidic groups were produced if higher concentrations of alkali were added. These carboxyl groups may contribute the acid/base interaction of the caustic-digested starch on hematite. Also, different concentrations of sodium hydroxide to digest starch seem to induce different degrees of its gelatinization from the SEM results, partially attributing to a wide range of its adsorption capacities on mineral surfaces. The optimum adsorption density of the caustic-digested starch on mineral surfaces, 9.87 mg/g hematite for sodium hydroxide and 10.51 mg/g hematite for potassium hydroxide, respectively, was achieved at the weight ratio of starch to sodium/potassium hydroxide as 1:2. [ABSTRACT FROM AUTHOR]

The current diagnosis of major depressive disorder (MDD) is mainly based on the patient's self-report and clinical symptoms. Machine learning methods are used to identify MDD using resting-state functional magnetic resonance imaging (rs-fMRI) data. However, due to large site differences in multisite rs-fMRI data and the difficulty of sample collection, most of the current machine learning studies use small sample sizes of rs-fMRI datasets to detect the alterations of functional connectivity (FC) or network attribute (NA), which may affect the reliability of the experimental results. Multisite rs-fMRI data were used to increase the size of the sample, and then we extracted the functional connectivity (FC) and network attribute (NA) features from 1611 rs-fMRI data (832 patients with MDD (MDDs) and 779 healthy controls (HCs)). ComBat algorithm was used to harmonize the data variances caused by the multisite effect, and multivariate linear regression was used to remove age and sex covariates. Two-sample t-test and wrapper-based feature selection methods (support vector machine recursive feature elimination with cross-validation (SVM-RFECV) and LightGBM's "feature_importances_" function) were used to select important features. The Shapley additive explanations (SHAP) method was used to assign the contribution of features to the best classification effect model. The best result was obtained from the LinearSVM model trained with the 136 important features selected by SVMRFE-CV. In the nested five-fold cross-validation (consisting of an outer and an inner loop of five-fold cross-validation) of 1611 data, the model achieved the accuracy, sensitivity, and specificity of 68.90 %, 71.75 %, and 65.84 %, respectively. The 136 important features were tested in a small dataset and obtained excellent classification results after balancing the ratio between patients with depression and HCs. The combined use of FC and NA features is effective for classifying MDDs and HCs. The important FC and NA features extracted from the large sample dataset have some generalization performance and may be used as a reference for the altered brain functional connectivity networks in MDD. • Propose a feature selection strategy to select important features of fMRI data. • Features extracted from large sample datasets have better generalizability. • Combining functional connectivity and network attribute facilitates classification. [ABSTRACT FROM AUTHOR]

The Jinbaoshan serpentine complex is characterized by low grades Cu, Ni and platinum group metals (PGM), and little is known about the relative abundance of the valuable minerals and gangue. With the aid of modern testing instruments, such as a scanning electron microscope (SEM) and an X-ray diffractometer (XRD), the occurrence and distribution of Cu, Ni and platinum group minerals (PGMs) were investigated in detail. Results show that eighteen categories of PGMs are found in the ore, mainly occurring as individual minerals; the PGMs are mainly disseminated in the sulfide in inclusions or semi-inclusions; some are inlaid along with other minerals to form a coarse assemblage. The base metal sulfides (BMS), such as pyrrhotite, pentlandite and chalcopyrite, are regarded as the "carrier" of PGMs, and serpentine is the major gangue, which has negative impact on mineral processing and extractive metallurgy. [ABSTRACT FROM AUTHOR]

A unified strategy for an efficient and high diastereo- and enantioselective synthesis of (-)-chloramphenicol, (-)-azidamphenicol, (+)-thiamphenicol, and (+)-florfenicol based on a key catalytic syn -selective Henry reaction is reported. The stereochemistry of the ligand-enabled copper(II)-catalyzed aryl aldehyde Henry reaction of nitroethanol was first explored to forge a challenging syn -2-amino-1,3-diol structure unit with vicinal stereocenters with excellent stereocontrol. Multistep continuous flow manipulations were carried out to achieve the efficient asymmetric synthesis of this family of amphenicol antibiotics.

This study was conducted to explore the feasibility of partial pancreatic head resection and Roux-en-Y pancreatic jejunostomy for the treatment of benign tumors of the pancreatic head (BTPH). From November 2006 to February 2009, four patients (three female and one male) with a mean age of 34.3 years (range: 21-48 years) underwent partial pancreatic head resection and Roux-en-Y pancreatic jejunostomy for the treatment of BTPH (diameters of 3.2-4.5 cm) using small incisions (5.1-7.2 cm). Preoperative symptoms include one case of repeated upper abdominal pain, one case of drowsiness and two cases with no obvious preoperative symptoms. All four surgeries were successfully performed. The mean operative time was 196.8 min (range 165-226 min), and average blood loss was 138.0 mL (range: 82-210 mL). The mean postoperative hospital stay was 7.5 d (range: 7-8 d). In one case, the main pancreatic duct was injured. Pathological examination confirmed that one patient suffered from mucinous cystadenoma, one exhibited insulinoma, and two patients had solid-pseudopapillary neoplasms. There were no deaths or complications observed during the perioperative period. All patients had no signs of recurrence of the BTPH within a follow-up period of 48-76 mo and had good quality of life without diabetes. Partial pancreatic head resection with Roux-en-Y pancreatic jejunostomy is feasible in selected patients with BTPH.

Roux-en-Y choledochojejunostomy is a common biliary reconstruction procedure. The collection of gallstones in the jejunal limb is a rare complication. Here we present a case of a 61-year-old Chinese female who received Roux-en-Y choledochojejunostomy 10 years ago. Diagnosis of recurrent bile duct stones accompanying infection was made before operation. She also had an abdominal mass which was possibly an intussuscepted colon or a huge fecolith. At laparotomy, an oval stone (5 cm in diameter) and 3 smaller multifaceted stones (2 cm in diameter) were found in the jejunal limb. A fistula between this jejunum and colon was also found. Although the typical manifestations of diarrhea were present, the diagnosis of a biliary colonic fistula was missed before operation. Partial colectomy was performed with the fistulous opening repaired. A T-tube was left in the jejunal limb and the mesocolon aperture was enlarged and revised. Her postoperative convalescence was uneventful. We report this case hoping to sharpen our diagnostic acumen.

The primers, DQAp161 and DQAp443, were designed based on the homologous region of SLA-DQA cDNA sequences and HLA-DQA genomic sequences. The 731 bp fragment of SLA-DQA including completed intron 2, the near completed exon 2 and partial exon 3 was obtained by PCR. The nucleotide sequences of the fragment of SLA-DQA were obtained with cloning and direct sequencing. Both nucleotide sequences of exon 2 and amino acid sequences of alpha 1 domain were analyzed in a pedigree. The sequence data were compared with all sequences of SLA-DQA exon 2 in GenBank. Two novel alleles, DQA-SLT 26 and DQA-TC 21-1, were found according to the above analyses. Four amino acid changes were observed among SLA-DQA haplotype c, d and DQA-SLT 26. They were Val-->Ala(60), Lys-->Glu(65), Asp-->Gly(81) and Lys-->Ile(93). Comparing the amino acids sequence of the all SLA-DQA sequences with DQA-TC 21-1 revealed that the His (94) was changed into Tyr.

A novel expressed sequence tag (ESThp9-1, GenBank accession number: B1596262) was isolated from pig skeletal muscular tissue by using the mRNA differential display technique. BLAST analysis revealed that the 196 bp long EST (ESThp9-1) was not homologous to any of the known porcine genes in the database but similar to rat U3A small nuclear RNA (87% identity over 93 nucleotides) and mouse U3B.4 small nuclear RNA (85% identity over 96 nucleotides). Semi-quantitative reverse transcription polymerase chain reaction indicated that EST9hp-1 was expressed in most of tissue of the pig. ESThp9-1 was physically mapped on sus scrofa chromosome 12q1.1-q1.5 and linked with microsatellite S0090 by using somatic cell hybrid panel and radiation hybrid panel analysis. According to the homologous information and result of physical mapping, ESThp9-1 was presumed to be one member of the porcine U3 gene family.