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Neoproterozoic magmatism associated with the assembly and configuration of the Rodinia supercontinent is widely distributed in the India-Himalayan terrane. However, its petrogenesis and tectonic settings remain controversial. This study provides new geochronological and geochemical data on the Neoproterozoic bimodal magmatism from the eastern Himalayan orogen. In situ zircon U Pb dating revealed that the protoliths of amphibolites were emplaced at ca. 826 Ma and the granitic gneisses have crystallization ages of 825–820 Ma. The granitic gneisses exhibit geochemical features of A-type granites, with high initial (87Sr/86Sr)i ratio (0.7182–0.7394), low whole-rock eNd(t) (−8.4 to −6.6), and variable zircon eHf(t) (−7.4 to +1.0) values. They were probably generated by partial melting of the ancient lower crust with minor input of mantle components. The amphibolite samples are enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs), suggesting an arc affinity. They have relatively high initial (87Sr/86Sr)i ratios (0.7113–0.7136), low whole-rock eNd(t) (−1.1 to 1.4) and a wide range of zircon eHf(t) (−4.1 to 8.3) values, indicating that the protoliths of amphibolites were likely generated by partial melting of an enriched subduction-modified continental lithospheric mantle. Their geochemical signatures are similar to typical back-arc basin basalts. The presence of coeval A-type granites and arc-related mafic rocks is probably due to the existence of a back-arc system. We argue that the Neoproterozoic bimodal magmatism is a product of back-arc extension initiated at an early stage, resulting from the rollback of the Mozambique Oceanic slab. Combined with previous studies on Neoproterozoic magmas from India and the Himalayas, we suggest that an extensive Neoproterozoic back-arc system may have existed along the northwestern margin of the Rodinia supercontinent. This theory supports a scenario of an Andean-type continental margin for the India-Himalayan terrane during the middle Neoproterozoic.

The Cuonadong deposit is located in southern Tibet and represents the first large-scale tin polymetallic deposit in the Himalayan region. Sn-(W) skarn mineralization is spatially related to leucogranites, whereas Be-Nb-Ta mineralization mainly develops in pegmatites. Alteration and veining in this deposit can be divided in to five stages: prograde skarn (stage I), retrograde skarn (stage II), cassiterite-quartz vein (stage III), cassiterite-sulfide vein (stage IV) and fluorite quartz vein (stage V). 40Ar 39Ar dating of muscovite from the skarn and phlogopite from the cassiterite-sulfide vein yield isochron ages of 15.4 ± 0.3 Ma and 15.0 ± 0.3 Ma, respectively, whereas U Pb dating of cassiterite from the skarn yields a Tera-Wasserburg low-intercept precise age of 14.2 ± 0.2 Ma. Zircon and monazite U Pb ages of the causative stanniferous leucogranites are 15.3 ± 0.1 Ma and 14.9 ± 0.2 Ma, respectively. Mineralization ages are consistent with the emplaced ages of the granites within the analytical uncertainties, which indicates that the tin polymetallic mineralization is genetically related to the Miocene leucogranites. Sn-bearing leucogranites have zircon eHf(t) values that vary from −13.3 to −8.5 (-10.7 on average), with an average TDM2 value of 1.56 Ga, which reveals that the leucogranites are derived from partial melting of ancient metasedimentary rocks. According to the zircon trace elements, the Miocene leucogranites are highly differentiated reduced S-type granites that formed at relatively high temperature. The average homogenization temperatures of fluid inclusions in different minerals that formed at stages II, III, IV and V are 351, 315, 240 and 175 °C, respectively, whereas their salinities are 8.3, 4.9, 9.5 and 3.8 wt% NaCl equiv., respectively. The C-H-O-S-Pb isotopes indicate that the ore-forming fluid and materials mainly originated from Miocene leucogranite. Dehydration and partial melting of mica in the Greater Himalayan crystalline complex due to east-west extension at 18–14 Ma developed the stanniferous leucogranite and ore-controlling fault system. Because of the pervasive occurrence of gneiss domes and Miocene Sn-bearing leucogranites similar to Cuonadong, the Himalaya has strong potential to be a new globally important Sn-(W) rare metal metallogenic belt.

Supplemental material, sj-docx-1-msj-10.1177_13524585211073761 for Tissue damage detected by quantitative gradient echo MRI correlates with clinical progression in non-relapsing progressive MS by Biao Xiang, Matthew R Brier, Manasa Kanthamneni, Jie Wen, Abraham Z Snyder, Dmitriy A Yablonskiy and Anne H Cross in Multiple Sclerosis Journal

Supplemental Material, sj-pdf-1-cns-10.1177_11795735221084842 for Stronger Microstructural Damage Revealed in Multiple Sclerosis Lesions With Central Vein Sign by Quantitative Gradient Echo MRI by Victoria A. Levasseur, Biao Xiang, Amber Salter, Dmitriy A. Yablonskiy and Anne H. Cross in Journal of Central Nervous System Disease

Background: Colon adenocarcinoma (COAD), a type of colon cancer, is among the most common malignant diseases afflicting people globally. Heat shock protein family, including HSPA8, are involved in tumor progression in numerous human cancers, however the association between HSPA8 and COAD has not been explored.Methods: RNA sequencing data and clinical characteristics from TCGA and GTEx, as well as protein data from CPTAC were obtained for analysis of HSPA8 expression in COAD. Furthermore, functional enrichment analysis of HSPA8-related differentially expressed genes (DEGs) was performed via GO/KEGG, immune infiltration analysis, and protein-protein interaction (PPI) network. In addition, the clinical significance of HSPA8 was analyzed by Kaplan-Meier Cox regression and prognosis assessment. R package was employed to analyze incorporated studies.Results: Compared with normal samples, the expression of HSPA8 increased remarkably in various tumors, including COAD, Moreover, high HSPA8 expression was associated with good prognosis in COAD, as well as subgroups with male, T2-T4 stage, no lymphatic and perineural invasion. (P < 0.05). High HSPA8 was a prognostic factor in Cox regression analysis. The diagnostic efficacy of HSPA8 in COAD analyzed by ROC (AUC: 0.889). Furthermore, a total of 3321 DEGs were identified between the high- and the low-expression group, of which 9 genes were up-regulated and 3312 genes were down-regulated.Conclusions: High HSPA8 expression is a potential biomarker for favorable outcomes in COAD. the results might provide clues and guidance for developing novel diagnosis, targeted therapy and prognosis of HSPA8 in COAD.

Herein, we report the mechanism of Ir(III)-catalyzed intermolecular branch-selective allylic C−H amidation, including the influence of substituent effect on yield and regioselectivity. The sequence of amidation reaction is alkene coordination, allylic C−H activation, oxidative addition of methyl dioxazolone, reductive elimination of allyl-Ir-nitrenoid complex, amine protonation and proto-demetallation. The apparent activation energy of amidation between hexene and methyl dioxazolone is 17.8 kcal/mol, and the energy difference between two transition state for formation amide is only 2.8 kcal/mol. The introduction of more electron-deficient groups at the allyl terminal increases the apparent activation energy, conversely, the introduction of electron-donating groups significantly reduces the apparent activation energy. Among them, the apparent activation energy of the reaction between aniline group substituted allyl and methyl dioxazolone is only 13.8 kcal/mol, which further improves the reaction yield. In addition, the introduction of more electron-withdrawing groups on dioxazolone can significantly improve the regioselectivity. When 3,4,5,-trifluorophenyl substituted dioxazolone and hexene occur C−N bond coupling reaction, the energy difference of the two transition states is as high as 9.0 kcal/mol, indicating that the regioselectivity is greatly improved. The mechanism explanation of allylic C−H amidation will provide strong theoretical support for streamlined synthesis of allyl branched amides.

Polymyxin is a critical antibiotic against the infection caused by multidrug-resistant gram-negative bacteria. Neurotoxicity is one of main dose-limiting factors. The present study aimed to investigate the underlying molecular mechanism on colistin induced peripheral neurotoxicity using a mouse model. Forty mice were divided into control, colistin 1-, 3- and 7-day groups, the mice were intravenously injected with saline or colistin (sulfate) at the dose of 15 mg/kg/day for 1, 3 and 7 days, respectively. The results showed that, colistin treatment for 7 days markedly resulted in the demyelination, axonal degeneration and mitochondria swelling in the mice’s sciatic tissues. Colistin treatment induces oxidative stress as well as the increases of mitochondrial permeability transition, decreases of membrane potential (ΔΨm) and activities of mitochondrial respiratory chain in the mice’s sciatic nerve tissues. Furthermore, in the colistin-7 day group, adenosine-triphosphate (ATP) level Na+/K+-ATPase activity decreased to 75.2% (p

To compare the clinical effect between electroacupuncture (EA) at Neima point and Neiguan (PC 6) and epidural nerve block for preemptive analgesia in patients undergoing thoracic surgery.Sixty patients with elective radical esophagectomy were randomly divided into a group A, a group B and a control group, 20 cases in each group. The patients in the group A were treated with injection of 20 mL 0.375% ropivacaine at epidural space 30 min before anesthesia induction, followed by normal anesthesia during operation; the patients in the group B were treated with 30 min EA at bilateral Neima point and Neiguan (PC 6) before anesthesia induction, followed by normal anesthesia during operation; the patients in the control group were treated with general anesthesia alone. Patient-controlled intravenous analgesia was applied for all the patients. The mean arterial pressure (MAP) and heart rate (HR) were recorded at the following time points: before acupuncture/epidural puncture (TThe MAP at TThe preemptive analgesia of EA at Neima point and Neiguan (PC 6) and epidural nerve block could both provide effective perioperative analgesia for thoracic surgery. The EA could better maintain intraoperative hemodynamics and has less physiological disturbance.

The migratory insertion of isonitriles into metal C bonds is a potentially important method for the formation of C C bonds in organic and pharmaceutical syntheses. In this context, the reaction mechanism of Cp * (pentamethylcyclopentadienyl)(Cl)Zr(diene) with isonitriles was studied using density functional theory calculations. Zr imido complexes and α-methylene cyclopentenimines are the confirmed products for N-t Bu-, N -2,6-diMePh-, and N -1-adamantyl-substituted isonitriles, whereas six-membered zirconacycles are the thermodynamically favored products for Me- and Et-substituted isonitriles. The β-H elimination pathway is responsible for the formation of α-methylene cyclopentenimines and zirconacycles. The kinetically favored products for MeNC and EtNC are diazazirconacyclopentanes ( σ complexes), which are formed via an isomerization pathway. The effects of substituents on the isonitrile nitrogen atom in the main elementary reactions are also discussed.

A density functional theory study is performed on the reactions of α,β-unsaturated oxime pivalates and alkenes through Cp*RhIII-catalyzed (Cp* = pentamethylcyclopentadienyl) C–H activation. The catalytic cycle involves reversible metalation–deprotonation, migratory alkene insertion, pivaloyl transfer to the Rh center, and reductive elimination, among other steps. The results show that the migratory alkene insertion is rate-determining and that the reductive elimination to form the product-ligated species makes the reaction irreversible (exergonic by 60 kcal/mol). If the electron-donating ability of the substituents on the cyclopentadienyl (Cp) ligand is increased or an electron-withdrawing group is introduced into the terminus of the alkene, the apparent activation energy of the reaction increases. In contrast, if a stronger electron-donating group is introduced at the 2-position of the α,β-unsaturated oxime pivalate, the apparent activation energy of the reaction decreases greatly, and the reaction can be performed at room temperature. On the other hand, for phenyl groups at the 2-position, the introduction of a more electron-deficient p-CF3-phenyl group increases the apparent activation energy. Finally, the diastereoselectivity of the reaction with cyclohexylethylene as the substrate is attributable to a clash between the cyclohexyl group and the α,β-unsaturated oxime pivalate.

In spite of their widespread use as catalysts, 1,2,3,4,5-pentamethylcyclopentadienyl (Cp*) iridium complexes have been rarely employed in the synthesis of pyridine derivatives. Herein, we used density functional theory (DFT) calculations to predict the [Cp*Ir(OAc)]+-catalysed synthesis of 2,3-dihydropyridines, which are important starting materials for pharmaceuticals, from α,β-unsaturated oxime pivalates and alkenes. The corresponding Cp*Rh complex-catalysed processes were discussed in comparison. The simulated catalytic cycle consists of several elementary reactions, such as reversible acetate-assisted metalation–deprotonation, migratory insertion of the alkene, pivaloyl transfer, and reductive elimination. The migratory insertion of the alkene is identified as the rate-determining step, and the reductive elimination to furnish the product-ligated species makes the reaction irreversible (exergonic by about 48 kcal mol−1). The stabilities of the intermediates and the energy barrier of migratory insertion of the alkene can be affected by introducing substituent groups with different electronic characteristics into Cp* and the 2-position of α,β-unsaturated oxime pivalates, as well as by using polarised alkenes. The apparent activation energy of the reaction can be increased by increasing the electron-donating ability of the substituent group on Cp*, and by introducing electron-withdrawing groups into the terminus of alkenes. When a strong electron-donating group such as the amido group is introduced into the 2-position of α,β-unsaturated oxime pivalates, the apparent activation energy is greatly reduced so that the reaction can occur at room temperature. In contrast, changing phenyl into the highly electron-deficient p-CF3-phenyl makes the reaction more difficult. Diastereoselectivity of the reaction was examined using cyclohexylethylene as a substrate, and a method for enhancing diastereocontrol was suggested.

The migratory insertion of isonitriles into the metal–C bond is important for constructing C–C bonds in organic and pharmaceutical syntheses. We examine the reaction of Cp*(Cl)Ti(diene) with isonitriles using density functional theory calculations. At room temperature, the bis-insertion reaction occurs easily for N-tert-butyl (tBu), methyl (Me), ethyl (Et), 2,6-dimethylphenyl (Ar), and N-1-adamantyl (1-Ad)-substituted isonitriles. The elementary reactions include the isomerisation of Cp*(Cl)Ti(diene), migratory insertion of the first isonitrile into a Ti–C bond, C–C reductive elimination, β-H elimination, migratory insertion of the second isonitrile into a Ti–H bond, and C–C reductive coupling. Two reliable fragmentation mechanisms are suggested for the bis-insertion products. For the bulkier tBuNC, ArNC, and 1-AdNC, the β-H elimination reaction pathway is dominant. For the smaller MeNC and EtNC, the γ-H elimination reaction pathway competes with the β-H elimination. For ArNC, the isomerisation reaction pathway to a newly predicted “σ complex” is kinetically favourable.

To investigate the clinical efficacy and safety of ultrasound-guided percutaneous nephrolithotomy (PCNL) assisted by a puncture frame.Clinical data of 106 patients with nephrolithiasis who underwent ultrasound-guided percutaneous nephrolithotomy from October 2016 to December 2017 in our hospital were analyzed retrospectively. The channels were established by the assistance of the puncture frame.The mean puncture time was 35 ± 18 seconds, the puncture was performed 1.3 ± 0.9 times on average. The puncture was successfully performed at first attempt in 73 cases. The mean operation time was 67.3 ± 39.2 min, and the mean intraoperative blood loss was 48 ± 22 mL. The stones were located on the left in 50 (47.2%) cases, and on the right in 56 (52.8%) cases. Channels were established through the upper, middle and lower calyces of the kidney in 78 (73.6%), 20 (18.9%), and 8 (7.5%) cases, respectively. The puncture sites were located on the upper and lower of 12th rib in 81 (76.4%) and 25 (23.6%) cases. Intraoperative and postoperative blood transfusion was given in four cases. Pleural injury occurred in two cases, and hydropneumothorax occurred in one case in whom closed thoracic drainage was performed. The stone free rate after a single surgery was 87.7% (93/106).Establishing a percutaneous nephrolithotomy access tract under ultrasound guidance using the puncture frame is an efficacious and safe approach.

A novel sheet-like Zn2+ doped Bi2MoO6 photocatalyst was fabricated through a facile hydrothermal strategy. The morphologies and chemical compositions of the samples were investigated with the help of powder X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS), energy dispersive X-ray analysis (EDS), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), Raman and FT-IR spectra. These experimental results indicated that Zn2+ ions could be incorporated into the crystal lattices of Bi2MoO6 and substituted the Bi3+ ions. Photocatalytic experiments revealed that the as-obtained Zn2+ doped Bi2MoO6 nanosheets possessed excellent UV-visible light induced photocatalytic ability for the decomposition of Rhodamine B (RhB) molecules by comparison with undoped Bi2MoO6. The effect of some scavengers on the photocatalytic efficiency was assessed. Moreover, a possible enhancement mechanism of photocatalytic activity over Zn2+ doped Bi2MoO6 nanosheets was presented based on the systematical characterization results.

The Kerguelen mantle plume triggered the rift of Eastern Gondwana to open the eastern Indian Ocean, with the formation of ~ 132 Ma Comei–Bunbury large igneous province (LIP). The Comei area is located in the eastern Tethyan Himalaya, paleogeographically belonging to Greater India. The Laguila bimodal intrusive rocks from the Comei area consist of mafic (gabbro-diabase) and felsic rocks (quartz monzonite-granodiorite). This paper presents detailed LA-ICP-MS zircon U-Pb chronology, major and trace elements, and Sr-Nd-Pb isotope geochemistry of the Laguila bimodal intrusive rocks, in order to constrain the early activity of the Kerguelen mantle plume. LA-ICP-MS zircon U-Pb dating shows that the Laguila intrusive rocks were emplaced in the Early Cretaceous (~ 134–130 Ma). The Laguila mafic rocks are enriched in LREE, LILE and HFSE, similar to those of oceanic island basalts (OIB). Their 87Sr/86Sri (0.7054 to 0.7066), 143Νd/144Nd (T) (0.512548 to 0.512619) and (206Pb/204Pb)t ratios (18.492 to 18.859) are comparable with those basalts derived by the Kerguelen hot spot. Elemental and isotopic data suggest that they were likely derived by partial melting of the Kerguelen plume source in the spinel–garnet transition zone (~ 60–80 km). The Laguila felsic rocks share most of the geochemical features of A-type granite and show different 87Sr/86Sri (0.7171 to 0.7204), 143Νd/144Nd (T) (0.511874 to 0.511956) and (206Pb/204Pb)t ratios (19.087 to 19.274) from those of the mafic rocks. They were likely derived by partial melting of crustal rocks at a shallow depth ( We calculated the magmatic volume of Comei–Bunbury basalts and the result is ~ 1.1 × 104 km3. The small volume is not reconciled with those typical models for the initial magmatic eruption of mantle plume. It was possible that the thick lithosphere (> 150 km) underneath Greater India prevented the Kerguelen plume from large-scale melting because of the high pressure when the latter impinged onto the former at ~ 132 Ma. The shallow source (~ 60–80 km) of the Laguila mafic rocks indicate that they originated likely from a series of “diapirs” or “fingers” rising from the head of the Kerguelen plume, which penetrated into the thick lithospheric mantle of Eastern Gondwana at enough shallow depth for melting.

The Cuonadong deposit is located in the Cuonadong gneiss dome of the eastern Tethyan Himalaya and is characterized as a large- to superlarge-scale Sn polymetallic deposit in the Himalaya orogen. The mineralization pattern includes skarn W-Sn mineralization in the strong shear zone of the dome mantle, hydrothermal Sn-W veins controlled by north-south-trending rifts (NSTRs), and Be-Rb mineralization in pegmatitic leucogranite. The results of this study show that the zircon U-Pb age of undeformed (postkinematic) leucogranites is 15.5 ± 0.1 Ma (n = 28, MSWD = 1.4), the cassiterite U-Pb age of the vein-type Sn-W orebody is 14.3 ± 0.5 Ma (n = 40, MSWD = 3.2), and the muscovite Ar-Ar age of beryl-bearing pegmatitic leucogranite is 15.2 ± 0.2 Ma (MSWD = 1.5). The isotopic dating results demonstrate that the Cuonadong Sn-W-Be-Rb mineralization has a close genetic relationship with the Miocene (ca. 16–14 Ma) leucogranite magmatic hydrothermal activity in the Cuonadong dome. The deformed (synkinematic) two-mica granite (18 Ma) was cut by the Sn-W ore veins (14 Ma) faulted by NSTRs, indicating that the E-W-trending extension of the NSTRs initiated at ca. 18–14 Ma. The Himalaya leucogranite belongs to a highly fractionated granite with high Sn content (>15 ppm). In conclusion, the Himalaya leucogranite is considered to be tin granite in this study, and therefore, the Himalaya presents high potential for Sn polymetallic mineralization prospecting.

In recent decades environmental pollution and energy crisis have become a challenging task for the scientists and engineers who lead them to innovate new technology and solve this problem by reducing environmental pollution and by exploiting the new source of energy. In this regard wave energy is appeared to be a suitable outcome in order to resolve the current issues. This paper studies and summarizes that the linear generators are considered a device which is used to convert wave energy into electrical energy efficiently. It is the first time to calculate the electromagnetic force by considering the linear generator and at the same time simulated by Ansoft Maxwell software; by providing calculated value and simulated value, it is also verified that the calculated result is accurate with a small probability error as compared to software calculated value.

Development of highly functional cesium selective adsorbents for the decontamination of high-activity-level water (HALW) from the Fukushima NPP-1 accident is very urgent. In order to selectively adsorb the radioactive cesium, three kinds of novel porous silica gels loaded with insoluble ferrocyanides (SLFC) were prepared using a successive impregnation/precipitation method. Based on the results of previous research, the SLFC composites have relatively large uptake ratio above 95%, distribution coefficients (K d) above 103 cm3/g, and excellent adsorption kinetics even in seawater. The solidification results also indicate that zeolites have an excellent Cs immobilization characteristic, gas-trapping and self-sintering abilities, and low leachability. We chose three kinds of SLFC composites to achieve the optimization of solidification by mixing with nine kinds of additives at high temperatures (up to 1200 °C). The Cs contents in the three composites were estimated to be below 30% of the initial contents and decreased with the three stages at calcination temperatures ranging from 25 to 1200 °C. By contrast, the Cs immobilization ratio was markedly lowered by mixing with additives: of those, allophane had the best immobilization result. By increasing the additive ratio to 50 wt%, the Cs immobilization ratio became almost 100% and no volatilization of Cs was detected even after calcination at 1200 °C. This result indicates that calcination of the mixture of SLFC composites after adsorbing Cs+ ions and specific additives under appropriate ratio is effective for stable solidification.

pea starch and acrylamide were used as the raw materials, potassium peroxodisulfate and sodium sulfite were used as the initiator, EDTA (Ethylene Diamine Tetraacetic Acid) and urea were used as the auxiliaries to make starch grafting acrylamide polymer flocculating agent by the method of aqueous solution polymerization. The influence of reaction temperature, concentration of initiator and raw material ratio on the flocculating performance of products was analyzed by ternary quadratic orthogonal regression rotational combination experiment. The result shows that the flocculation effect will be the best when the reaction temperature is 60°C, the initiator is 5.00 ml, and the raw material ratio is 2.25.

We report on the enhanced interfacial adhesion of diamond coating on copper substrate modified by a small fraction of Al. For pure copper substrate, the diamond coating formed tends to crack and delaminate, primarily caused by a slight accumulation of detrimental graphite intermediate layer and thermal stress induced by mismatch of the coefficients of thermal expansion. Additions of 1 and 3 at.% Al to the copper substrate gradually decrease the intermediate graphitic phase. At the higher Al concentration, an aluminium oxide forms at the coating–substrate interface, and graphitic/amorphous carbon is completely inhibited, leading to significantly enhanced interfacial adhesion of diamond coating. The electron structure of copper is not observed to significantly alter on this Cu–Al dilute alloy. The alumina barrier layer preferentially formed on copper surface is believed to play a key role in preventing graphitization and adhesion enhancement.

Bamboo vinegar and sulfuric acid are used as acidifier and the method of precipitation is adopted to synthesize the antibacterial white carbon black. Orthogonal experiment was carried out to investigate the influence of reaction temperature, the amount of bamboo vinegar, additive amount of polyethylene glycol, the concentration of sodium silicate and amount of priming water on the oil absorption value of white carbon black. The analysis of orthogonal experimental results shows that influence of temperature, amount of priming water and the additive amount of PEG on oil absorption value is extremely remarkable. The influence of the amount of bamboo vinegar is remarkable, but the concentration of sodium silicate is indistinctive. It is verified through experiments that the specific surface area and oil absorption value of product is high, and its antibacterial effect is good.

PCL/PVP blend membrane was prepared by casting solution method. Scanning electron microscopy (SEM), diffraction scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques were employed to characterize membrane structure and morphology. Moreover, the hydrophilicity, mechanical property and biodegradability of membranes were investigated. Due to introducing PVP, the crystallinity and mechanical property of PCL altered to some extent. The hydrophilicity of the blend membrane improved remarkably with increasing PVP content, which was expressed by the contact angle declining and the rate of water absorption increasing. Lipase accelerated the degradation rate of PCL/PVP membrane.

Since the Guangzhou municipality in south China organised the first Overseas Students Fair in 1998, large conventions aimed at recruiting overseas Chinese professionals (OCPs) have become a regular scene in major cities in China. These conventions constitute one of the most visible means of the Chinese government's engagement with the 800,000 OCPs who remain overseas after receiving tertiary education abroad. Characteristic of the conventions, and OCP policies in general, is a highly ‘materialistic’ thinking: it is argued that OCPs deserve generous financial rewards because they are economically and technologically beneficial to China, and that financial reward is the most feasible means to attract them back. My ethnographic data, however, reveal that the language of economism is communicated in a highly ritualistic manner and, conversely, political rituals serve as a crucial part of the conventions. The ritualised economic- and technological-determinist discourse appears apolitical, yet acquires strong m...

Raman spectra of Al- and N-doped 6 H-SiC crystal samples with different doping levels were measured. The first-order Raman spectra of the samples were shifted to higher frequency when the doping concentrations were increased. Compared with Al-doped samples, the intensity of A 1 longitudinal optical mode of N-doped ones changed obviously, which reflected the different doping concentrations. The second-order Raman spectra were not dependent on the doping types and concentrations.

Two types of donor(D)–acceptor(A) calix[4]arenes have been theoretically studied using DFT//B3LYP/6-31G(d) method and ZINDO/CISD method. The calculations show that the substitution of CC by the conjugation bridge CC and NN plays an important part in altering one-photon absorption (OPA) and two-photon absorption (TPA) properties. The maximum OPA wavelengths of all studied compounds are less than 400 nm, which means high transparency. The geometry of the calixarenes strongly influences the TPA properties of the studied compounds. In addition, the nitro derivatives have a wider TPA response range than other non-nitro derivatives. The tetrasubstituted calix[4]arenes (type B calixarenes) have a larger TPA cross-section values than the bisubstituted calix[4]arenes (type A calixarenes). Copyright © 2009 John Wiley & Sons, Ltd.

Two series of porphyrin-thiophene chromophores were theoretically studied that exhibit large two-photon absorption cross-section in the visible region. The density functional theory (DFT) associated with ZINDO/SDCI methods has been used to calculate the molecular geometries, electronic structures, one-photon and two-photon absorption properties. The results show that the number of thiophene units affects the properties of one-photon absorption (OPA) and two-photon absorption (TPA). Porphyrin-thiophene chromophores featuring two or three thiophene units have wide TPA response ranges; they can be applied to many nonlinear optical areas, such as optical limiting. Intervening ethynyl unit is beneficial to extend the conjugated pathway, and increase the two-photon absorption cross-section. At the same time, the OPA and TPA wavelengths are bathochromically shifted. From viewpoint of the high transparency and large nonlinear optical response, porphyrin-thiophene chromophores will be promising TPA materials.

The electronic structures, one-photon absorption (OPA) and two-photon absorption (TPA) properties of the azulenylporphyrins and azulene-fused porphyrins have been comparatively studied by using DFT/B3LYP/6-31G(d) and the ZINDO/SDCI method. With the number of azulenyl groups increasing, the OPA wavelengths of all molecules are red-shifted in 400{600 nm and the two-photon absorption cross section is gradually enlarged. The azulene-fused structures facilitate an expanding conjugated area and increasing TPA cross section. The origin of TPA properties of studied compounds is studied with a two-level model. In summary, the azulene-fused porphyrins exhibit strong two-photon absorption.

Two series of bis(styryl)benzene derivatives (BSBD), namely the single-BSBD and the double-BSBD, were investigated. The equilibrium geometries and electronic structures were obtained by using the density functional theory B3LYP and 6-31G basis set. In succession, the one- and two-photon absorption properties of all the molecules were studied theoretically with a ZINDO-SOS (sum-over-states) method in detail. It can be seen that the double-BSBDs have larger two-photon absorption (TPA) cross sections in the visible-IR range than the corresponding single-BSBDs, demonstrating that increasing the molecular dimension is a very effective method to enhance the values of the TPA cross sections. On the other hand, it can be also noticed that the values of the TPA cross sections are correlative with the ability of donating (accepting) electrons of the terminal substituent groups R [N(CH3)2, CH3, H and CF3] in these molecules. That is, the intramolecular charge transfer is also a factor for the enhancement of the TPA efficiency. To sum up, the idea of increasing the molecular dimension to enhance the TPA cross section value is a helpful direction to explore better TPA materials for practical applications. And the double-BSBD molecules are promising TPA materials for the further investigation from the standpoint of the high transparency and the larger TPA cross sections.

The equilibrium geometries, electronic structures, one- and two-photon absorption (TPA) properties of a series of octupolar complexes with the Cu(I), Zn(II) and Al(III) as coordinate centers and the bis-cinnamaldimine as ligands have been studied using the B3LYP/6-31G(d) and ZINDO-SOS methods. Compared with the dipolar metal complexes, all the octupolar metal complexes (including tetrahedral and octahedral complexes) have relatively large TPA cross-sections, indicating that building octupolar metal complex is an effective route to design of promising TPA material. Lewis acidity of metal center and molecular symmetry are two important factors for enhancement of TPA cross-section of metal complex. Due to the stronger Lewis acidity of Zn(II) than Cu(I) as well as Al(III) than Zn(II), the tetrahedral Zn(II) complex exhibits a TPA cross-section larger than that of the tetrahedral Cu(I) complex, the maximum TPA position of the octahedral Al(III) complex is red-shifted relative to the octahedral Zn(II) complex, and at the same time, the octahedral Al(III) complex has a large TPA cross-section. Compared with the tetrahedral complexes, the TPA cross-sections of the octahedral complexes are enhanced due to the increased number of ligands.

Since the topic of ‘brain drain’ was introduced to the United Nations’ debates in the late 1960s, policy thinking on skilled migration has shifted its focus from discouraging emigration in the 1970s to encouraging returns in the 1980s, and to facilitating ‘brain circulation’ since the 1990s. This paper, based on a comparison between China and India in the Information Technology (IT) industry, suggests that how the highly skilled leave the home country in the first place is equally important as how they return or contribute back through transnational connections. IT professionals’ migration from India with minimum government intervention may have more sustainable developmental effects than aggressive government programmes in China aimed at promoting return and transnational relations. This is because the migratory process of the Indian IT professionals is built into the dynamics of the global high-tech industry. By comparison, many programmes in China are dissociated from industry despite the heavy investm...