The mystery of Ph3PS revealed in magic-size Ag-S cluster nucleation.

The synthesis of atomically precise semiconductors Ag-S clusters is a subject of intense research interest, yet the formation mechanism of such nanoclusters remains obscure due to their uncontrolled fast nucleation process in solution. Herein, we have investigated the reaction mechanism responsible for {Ag32S3} nucleation using UV, ESI-MS, NMR and SCXRD analyses. Triphenylphosphorus sulfide (PPh3S) was surprisingly found to slow down the kinetic process of the cluster nucleation. Furthermore, a key precursor [Ag2(Ph3PS)4]2+ was captured, which was attacked by Agn(CCBut)m and traces of water to generate {Ag32S3}. This mechanism provides valuable new insights into the synthesis of inorganic magic-size clusters.

A chloride-doped silver-sulfide cluster [Ag148S26Cl30(CCBut)60]6+: hierarchical assembly, enhanced luminescence and cytotoxicity to cancer cells.

The formation of high-nuclear silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we report an unprecedented gigantic Ag148 ([Ag148S26Cl30(CCBut)60](SbF6)6) cluster co-templated by Cl- and S2-, which was well-defined by single-crystal X-ray diffraction and high-resolution mass spectrometry. The cluster exhibits a hierarchical structure consisting of fused Ag24X16 kernel, Ag60X20 shell and "cluster of clusters assembling" of four pentagonal concave polyhedral {Ag16X5} units. Furthermore, the silver cluster emits red light at room temperature with a prominent 39.6% QY. The cellular uptake and cytotoxicity indicate that Ag148 induces apoptosis of cancer cells in a dose-dependent manner.

Unusual structural transformation and luminescence response of magic-size silver(I) chalcogenide clusters via ligand-exchange.

Structural transformations of nanoclusters provide a platform to tune their properties and understand the fundamental science due to their intimate structure-property correlation. Here, we present an alkynyl ligand-exchange induced growth of atomically precise silver(I) clusters, which are particularly of interest because of their luminescence response at room temperature. SCXRD and UV-vis map out the growth steps of the cluster from [Ag32S3(CCBut)23]3+ featuring a pseudo-D3h concave Ag32S3 to [Ag45S6(CCPhBr)32]+ with a pseudo-Oh core-shell Ag9S6@Ag24@Ag12, which is driven by a thermodynamic route under the disruption of ligands. To our knowledge, the findings in this work establish the first example of ligand-exchange as a versatile tool for tuning the size and luminescence of semiconductor silver(I) clusters.

Solvent-driven crystal-crystal transformation and morphology change in a 2D layered inorganic POM-based framework.

In this paper, a pure 2D inorganic POM-based framework underwent a single crystal to single crystal conversion when soaked in organic solvents that are miscible with water, forming a more densely packed identical framework accompanying the formation of nanowires. The change in morphology is closely related to the surface tension of water, and the lower surface tension achieved by dehydration promotes the formation of nanowires, which is revealed by SXRD, PXRD, SEM, TGA and electrochemical impedance spectroscopy (EIS).

Synthesis of a novel phosphazene-based flame retardant with active amine groups and its application in reducing the fire hazard of Epoxy Resin.

A novel compound containing active amine groups of polyphosphazene (PBFA) was successfully synthesized and applied as a reactive flame-retardant additive in epoxy (EP) resin. It was synthesized from N-aminoethylpiperazine and hexachlorocyclotriphosphazene using a simple method, and its structure was well-characterized. The results indicated that introducing PBFA into EP composites significantly improves the resistance to fire and suppresses smoke generation. An EP composite with 9.0 wt% PBFA can pass the vertical burning tests V-0 rating, the peak heat release rate and total heat release of the sample decreased by 46.7% and 29.3%, respectively. Moreover, it decreased the total smoke release by 48.0%. Thermogravimetric analysis showed that the presence of PBFA can accelerate EP decomposition at comparatively low temperatures and lead to the formation of a stable char layer, which protects the matrix from fire, therefore improving the amount of char residue at 800 °C. The degree of small molecule degradation characterized by gas chromatograph/mass spectrometer, which was lower than that of pure EP, demonstrating that PBFA reduces the risk of fire. The glass transition temperature of EP composites increased with the amount of PBFA increasing owing to the presence of active amine groups. Notably, its mechanical properties were not degraded.

[Origins determination of Herba Abri cantoniensis and Herba Abri mollis with FTIR combined with fuzzy cluster and curve-fitting].

The methods of fuzzy cluster and curve-fitting combined with FTIR were used to determine the origins of Herba Abri cantoniensis and Herba Abri mollis. The spectra of Herba Abri cantoniensis and Herba Abri mollis are similar, both with typical spectral shapes. The two spectra can be divided into 3 parts: the 1st is 3 500-2 800 cm(-1), containing stretching bands of -OH, N-H, and CH2 ; the 2nd is 1 800-800 cm(-1), containing stretching bands of ester carbonyl group and indican C-O(H), vibrational bands of C=C and benzene ring; The 3rd is 800-400 cm(-1), containing skeletal vibration and scissoring vibration of molecular. The recorded FTIR spectral data were processed by 9-point-smoothing, 1st derivative, SNV and fuzzy cluster analysis sequentially. The fuzzy cluster analysis was carried out by similarity or dissimilarity matrix, and two matrices are computed with Manhattan and Euclidean distance. The results indicated that the optimization used Manhattan and dissimilarity matrix, and 5 origins of Herba Abri cantoniensis were perfectly discriminated, but 2 origins of Herba Abri mollis were mixed and identified from the other 3 origins. So the characterized bands at 1 034 cm(-1) of the average 1-D spectra of Herba Abri cantoniensis and Herba Abri mollis were fitted combining 2nd derivative for further distinguishing their spectral characteristic. The results of curve-fitting showed that the bands of wild Herba Abri cantoniensis and the other origin ones were decomposed to 11 and 9 component bands respectively, but the bands of Shanglin and the other origins Herba Abri mollis were decomposed to 9 and 8 component bands dissimilarly, and the locations and normalized densities of these component bands were different. From this, together with the results of fuzzy cluster analysis, it is concluded that the combination of two methods may identify the origins of Herba Abri cantoniensis and Herba Abri mollis availably.

[AOTF-near infrared spectroscopy for determining tanshinone II A in returning extraction process of Salvia miltiorrhiza].

OBJECTIVE: To explore a method on-line determining the contents of tanshinone II A in returning extraction process of Salvia miltiorrhiza by AOTF-Near infrared spectroscopy. METHODS: Firstly, the sample was collected in the extraction process of Salvia miltiorrhiza. Then HPLC was used as a reference method to determine the contents of tanshinone II A in the sample. Multivariate calibration models based on PLS1 algorithm were developed to correlate the spectra and the corresponding values determined by the reference methods. RESULTS: RMSECV of the models for tanshinone II A was 0.0092. The correlation coefficients of the calibration models was 0.9918. External validation with external validation samples proved that the relative deviation was 5.74%. CONCLUSIONS: AOTF-NIRS can be used in the determination of tanshinone II A in returning extraction process of Salvia miltiorrhiza. The method is rapid, accurate and non-destructive, and can be applied for process analysis and quality control of Chinese medicine manufacturing process.

[A new method for quick identification for fufang danshen tablets by AOTF-near infrared spectroscopy].

OBJECTIVE: To establish a new method using AOTF-Near infrared spectroscopy for fast identifying Fufang Danshen tablets. METHOD: Near-infrared spectroscopy of Fufang Danshen tablets from different factories and different bacth numbers were collected and the discriminant analysis model (FFDS-C) was established with principal component analysis. This model was applied to predict the the different samples of Fufang Danshn tablets. RESULT: The model can be used to precisely identify Fufang Danshen tablets from other samples. CONCLUSION: The method with low consumption is simple and quick and can be applied to the identification of the Fufang Danshen tablets.

[Effect of chlorine and phosphorus on water soluble and exchangeable lead in a soil contaminated by lead and zinc mining tailings].

Effect of chlorine on in situ lead immobilization using phosphorus in a soil contaminated by lead and zinc mining tailings was evaluated. The results showed that water soluble and exchangeable Pb were reduced by 92.0%-95.1% in the soil after P application. It was also suggested that application dosage of phosphorus at the P/Pb molar ratio of 0.6, was enough to remediate Pb toxicity in the soil. Compared to without Cl treatment at the level of molar ratio of 0.6 P/Ph, water soluble and exchangeable Pb in the soil treated with Cl was reduced markedly. It was concluded that the effects chlorine addition on in situ lead (Pb) immobilization using phosphate were improved. Visual MINTEQ model was employed to figure out Pb and P species distribution and saturation indices for minerals in the soils treated by P and Cl. The results showed that Pb activity was controlled by lead phosphate in the soil, especially pyromorphite [Pb5(PO4)3Cl], which would be the reason for Pb bioactivity reduction in the soil after application of Cl and P. The effective Pb bioactivity reduction indicated that addition of Cl was necessary to to improve in situ lead immobilization using phosphorous in the lead-contaminated soil.

[Preparation and structural characterization of mixed LB films of TMB * TCNQ and stearic acid].

Mixed LB films of the CT complex of TMB * TCNQ and stearic acid (SA) were prepared. The structures, molecular orientation and morphology of the mixed LB films were characterized by IR, UV-Vis-NIR, XRD and AFM. Our results show that TMB * TCNQ could be deposited on solid substrates by mixing with SA. The complex is mixed-stack, and the degree of charge transfer is 0.35. The chromophore planes of both TCNQ and TMB are perpendicular to the substrate surface and the hydrocarbon chain of SA is inclined at an angle with respect to the substrate surface. There are two kinds of diffraction bands in the XRD spectra, and they probably arise from SA and TMB * TCNQ, respectively. The morphology of mono- and multilayer mixed LB films with molar ratio 1 : 1 consists of many nanorods and particles, and the amount of nanorods and particles increase with increasing the number of monolayers.

Microemulsion-mediated hydrothermal synthesis of photocatalytic TiO2 powders.

A reverse microemulsion-mediated hydrothermal route has been employed to synthesize photocatalytic titanium dioxide (TiO2) powders. Nano-crystalline monophasic anatase TiO2 powders were successfully prepared when the microemulsion-derived precursors were hydrothermally treated. The advantage of using this microemulsion mediated hydrothermal route is the significant reduction in reaction time and temperatures as compared with the conventional hydrothermal process. The oil/water emulsion ratio significantly affected the particle sizes of the obtained TiO2 powders. The specific surface area of TiO2 powders was increased with the oil/water ratio, thereby leading to enhanced photocatalytic activity of TiO2 powders. As the hydrothermal temperature was elevated, the morphology of the TiO2 particles changed from a rod-like shape into a polyhedral shape. The variation in microstructures decreased the specific surface area of the TiO2 powders and lowered the photocatalytic activity.

[Optimization of manninotriose preparation from stachoyse].

OBJECTIVE: To optimize the processing of mannatriose preparation from stachyose by acidolysis. METHODS: An orthogonal experiment was performed to select a better condition of acidolysis. Fructoes and stachyose was determined by HPLC. RESULTS: Among the factors set in the present work, temperature and time have little influence on the acidolysis, while the effect of pH value was significant (P < 0.05). The best processing was selected as heating stachosy solution for 12h at pH 2.5 and 90 degrees C. CONCLUSION: It is practicable to prepare manninotriose from stachyoses by acidolysis.

Synthesis of photocatalytic TiO2 thin films via the high-pressure crystallization process at low temperatures.

TiO2 thin films with a monophasic anatase structure were synthesized via a high-pressure crystallization (HPC) process which successfully lowered the crystallization temperature of TiO2 films from 350 to 150 degrees C. The thermal budget and energy consumption during the crystallization process were markedly reduced and dense films without cracks were obtained. During the HPC process, crystallization took place throughout the films and TiO2 films with uniform crystallinity were obtained. The HPC process also led to an enhancement in the wettability of TiO2 thin films. The hydrophilicity of the films increased with heating temperatures via high-pressure annealing. In comparison with the conventional annealing, the HPC process not only produced TiO2 films with superior photo-induced super-hydrophilicity, but also led to higher photocatalytic activity of the films. The HPC process was confirmed to provide a new route for synthesizing well-crystallized anatase TiO2 thin films with high photocatalytic activity and good wettability at low temperatures.

Prevalence and risk factors of facial acne vulgaris among Chinese adolescents.

UNLABELLED: Acne vulgaris, a very common condition among adolescents, can result in psychological distress, including anxiety and depression. The purpose of this study was to assess the prevalence and risk factors of acne vulgaris among Chinese adolescents. In the Zhou Hai district of Guangdong Province, 3163 students 10 to 18 years old were selected from 7 schools. Information was collected using self-administrated questionnaIres and physician examinations. The prevalence of acne vulgaris was calculated from the collected data. Potential risk factors including age, gender, diet, skin type, sleeping habits, and facial make-up use were analyzed using stepwise logistic regression. The results showed a prevalence of acne vuglaris of 53.5% in all adolescents, with 51.3% in males and 58.6% in females. The prevalence of inflammatory acne in males and females combined was 25.8% and of acne scarring 7.1%. Increased age was related to higher prevalence and severity of acne vulgaris: 15.6%, 44.9%, and 70.4% for 10, 13, and 16 year olds, respectively. Acne vulgaris was more prevalent in girls under and boys over 14 years of age. Significant risk factors of acne vuglaris included age, skin type (oily, mixed, or neutral skin in comparison with dry skin), insufficient sleep, and cosmetic make-up use. CONCLUSION: Acne vulgaris is prevalent among Chinese adolescents 10 to 18 years old. Health education to address this condition in Chinese adolescents could have important implications for public health.

[Quality evaluation of soil fluorine on Hangjiahu Plain based on GIS].

Contents of fluorine in the plough layer (0-20 cm) of paddy soils from Hangjiahu Plain were investigated to evaluate quality of fluorine using total fluorine index method. Kriging method was applied to study the spatial variability of soil total fluorine in relation to their influential factors and their distribution maps were obtained based on GIS. The results showed that the range of total fluorine (TF) contents in the soils from central and eastern parts of Hangjiahu Plain was higher than that from the western part. The concentrations of TF in soil had a close relationship with parent material, pH value, organic matter, cation exchange capacity content and soil texture. The main range of TF was 200-300 mg/kg, while TF contents accounting for 23.7% of the area were less than 200 mg/kg in the studied area. In which TF contents in soil in Yuhang County were the lowest, less than 100 mg/kg.

[Extraction and salting-out purification of alpha-galactosidase and beta-glucosidase from fresh roots of Rehmannia glutinosa].

OBJECTIVE: To extract and preliminarily purify alpha-galactosidase and beta-glucosidase from the fresh roots of Rehmannia glutinosa. METHODS: With the enzyme activity as a criterion, the best procedure of extraction was selected though orthogonal design method, and the desired saturation of ammonium sulfate in two-step salting-out was settled by gradient sedimentation of root extract according to enzyme activity and protein content. RESULTS: Temperature and solvent volume affect the extraction of alpha-galactosidase significantly, while solvent type to beta-glucosidase. Therefore the procedure for extracting two enzymes was decided as mixing comminuted fresh root with 3 times phosphate buffer, and placing the mixture in refrigeratory at 4 degrees C for 4 hours, and then obtaining the enzyme liquid by centrifuging at 4 degrees C. 30% and 60% saturation was defined as the lower and upper point for two-step ammonium sulfate salting-out of the two enzymes. CONCLUSION: alpha-Galactosidase and beta-glucosidase exist in the fresh roots, and can be preliminarily purified through two-step salting-out.

[Application of Raman spectra to the research of jades excavated from Xue Jiagang site].

Non-destructive analysis is always the aim in jades' research. The present article applied the Raman spectroscopy to the research on jades excavated from the Xue Jiagang site and achieved good result in the main mineral, inclusion and phenocryst. The study shows that as a non-destructive technique Raman spectroscopy can be applied to ancient jades conveniently and practically, and it can detect not only the surface information of ancient jades, but also the interior information. The technique is important to the verification and provenance of ancient jades.

Biological formation of 5-aminolevulinic acid by photosynthetic bacteria.

In this study, 7 stains of Rhodopseudomonas sp. were selected from 36 photosynthetic bacteria stains storied in our laboratory. Rhodopseudomonas sp. strain 99-28 has the highest 5-aminolevulinic acid(ALA) production ability in these 7 strains. Rhodopseudomonas sp. 99-28 strain was mutated using ultraviolet radiation and a mutant strain L-1, which ALA production is higher than wild strain 99-28 about one times, was obtained. The elements affecting ALA formation of strain 99-28 and L-1 were studied. Under the optimal condition( pH 7.5, supplement of ALA dehydratase(ALAD) inhibitor, levulinic acid(LA) and precursors of ALA synthesis, glycine and succinat, 3000 Ix of light density), ALA formation of mutant L-1 was up to 22.15 mg/L. Strain L-1 was used to treat wastewater to remove COD(Cr) and produce ALA. ALA production was 2.819 mg/L, 1.531 mg/L, 2.166 mg/L, and 2.424 mg/L in monosodium glutamate wastewater(MGW), succotash wastewater(SW), brewage wastewater(BW), and citric acid wastewater(CAW) respectively. More than 90% of COD(Cr) was removed in four kinds of wastewater. When LA, glycin and succinate were supplied, ALA production was dramatically increased, however, COD(Cr) could hardly be removed.

In vitro activities of tigecycline against clinical isolates from Shanghai, China.

To evaluate the in vitro activity of tigecycline, the minimum inhibitory concentrations (MICs) of tigecycline against 1,201 strains of recent clinical isolates from 10 hospitals in Shanghai, China were determined and compared with selected comparators. Results showed that tigecycline had broad-spectrum antimicrobial activity. It was highly active against Gram-positive cocci, including methicillin-resistant Staphylococcus spp., penicillin-intermediate Streptococcus pneumoniae, Enterococcus faecalis and E. faecium. Tigecycline also had good activity against most strains of Enterobacteriaceae, Haemophilus influenzae, Neisseria gonorrhoeae, and Moraxella catarrhalis. However, it was poorly active against Acinetobacter baumannii and Pseudomonas aeruginosa. Tigecycline was highly active against anaerobic Gram-positive cocci such as Peptococcus spp. The in vitro activity of tigecycline was significantly better than that of minocycline and tetracycline. It was as active as or slightly more active than vancomycin and teicoplanin in the activity against resistant aerobic Gram-positive cocci. Tigecycline was bactericidal against all Gram-positive cocci tested except Enterococcus spp. Inoculum size but not pH of medium or concentration of human serum in broth had significant effect on the in vitro activity of tigecycline. Aged media (48-72 hours after preparation) used in the test and specific resistance problem in China may have some effects on MIC values of tigecycline.