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This study examines the effectiveness of classroom-based student writing tutors with discipline-specific backgrounds as adjunct collaborators in supporting non-native English-speaking writing teachers in the disciplines. In this qualitative study, the participants' perceptions of this collaborative instructional model were evaluated through a thematic analysis of semistructured interviews with the participating students, in-class writing tutors, and writing instructors from two disciplinespecific writing courses. The findings highlighted the perceived benefits of this collaborative teaching with discipline-specific tutors and their involvement as the "pedagogical bridge" to overcome language teachers' insufficiency of disciplinary content knowledge. The findings also pointed to pedagogical challenges concerning writing variations within the same discipline and students' need for linguistic knowledge rather than discipline-specific content knowledge. Based on these findings, this study concludes with a discussion of the pedagogical implications for the effective training of discipline-based tutor collaboration and the future implementation of discipline-based writing curricula across disciplines. [ABSTRACT FROM AUTHOR]

A novel high-temperature dielectric and quadratic nonlinear optical switching material, 3,4-difluoroanilinium 18-crown-6 perchlorate, was synthesized. It exhibits two successive structural phase transitions at 347 K and 240 K, respectively. Gradually increased SHG-active characteristics are also identified. [ABSTRACT FROM AUTHOR]

To evaluate the impacts of anthropogenic events on the rapid urbanized environment, the levels of legacy organochlorine pesticides (OCPs) and current-use insecticides (CUPs), i.e., dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), pyrethroids and organophosphates in soil of the Pearl River Delta (PRD) and surrounding areas were examined. Spatial concentration distributions of legacy OCPs and CUPs shared similar patterns, with higher concentrations occurred in the central PRD with more urbanization level than that in the PRD's surrounding areas. Furthermore, relatively higher concentrations of OCPs and CUPs were found in the residency land than in other land-use types, which may be attributed to land-use change under rapid urbanization. Moderate correlations between gross domestic production or population density and insecticide levels in fifteen administrative districts indicated that insecticide spatial distributions may be driven by economic prosperity. The soil–air diffusive exchanges of DDTs and HCHs demonstrated that soil was a sink of atmospheric o , p ′-DDE, o , p ′-DDD, p , p ′-DDD and o , p ′-DDT, and was a secondary source of HCHs and p , p ′-DDT to atmosphere. The soil inventories of DDTs and HCHs (100 ± 134 and 83 ± 70 tons) were expected to decrease to half of their current values after 18 and 13 years, respectively, whereas the amounts of pyrethroids and organophosphates (39 and 6.2 tons) in soil were estimated to decrease after 4 and 2 years and then increase to 87 and 1.0 tons after 100 years. In this scenario, local residents in the PRD and surrounding areas will expose to the high health risk for pyrethroids by 2109. Strict ban on the use of technical DDTs and HCHs and proper training of famers to use insecticides may be the most effective ways to alleviate the health effect of soil contamination. [ABSTRACT FROM AUTHOR]

Abstract: The occurrence of polycyclic aromatic hydrocarbons (PAHs) in soil of the Pearl River Delta (PRD) and surrounding areas was examined on a basis of six land-use types and four geographic regions, from which the impacts of anthropogenic events on the terrestrial environment were evaluated. No significant difference in the concentrations of Σ28PAH and Σ15PAH (sums of 28 and 15 PAHs, respectively) was found among the land-use types of industry, landfill and residency. On the other hand, higher soil PAH concentrations occurred in the central PRD characterized by dense population and high urbanization level, compared to other geographic regions. Source diagnostics implicated the combustions of coal and refined petroleum as the major input sources of anthropogenic PAHs. Furthermore, low molecular weight PAHs tended to volatilize from soil to air while the opposite was prevailing for high molecular weight PAHs. The mean annual diffusive flux of Σ15PAH (852μgm−2 yr−1) from the soil to the atmosphere in the central PRD was greater than those in the PRD's periphery (195μgm−2 yr−1), West region (322μgm−2 yr−1) and East region (84.9μgm−2 yr−1), suggesting that the central PRD may have become a secondary source of PAHs to the surrounding areas. Finally, ecological risk assessment based on the classification from Maliszewska-Kordybach showed that 3.5% of soil within the central PRD was heavily contaminated by PAHs and 5.2million residents may be subjected to high health risk. [Copyright &y& Elsevier]

Abstract: Rapid economic growth in South China (including Guangdong Province, Hong Kong, and Macau), particularly within the Pearl River Delta region, has resulted in severe pollution of the natural eco-environment in the last three decades. Large amounts of monitoring data on organic pollution in the Pearl River Delta have been accumulated, which allows us to conduct a fairly comprehensive assessment of the state of the Pearl River Delta and elucidate spatial and temporal patterns of pollution on a regional scale. Of various causes for environmental deterioration, negative impact from persistent organic pollutants (POPs) is a global concern. This review examines the current levels and distribution patterns of several POPs, namely DDT (and its metabolites DDD and DDE), hexachlorocyclohexanes, and polybrominated diphenyl ethers, in various environmental compartments of South China. The general information on environmental occurrence, regional behaviors, ecological effects, and human exposure of these POPs in this region are reviewed. [Copyright &y& Elsevier]

Abstract: P-toluenesulfonic acid (TSA) doped polypyrrole (PPy) binary nanocomposite and MnO2/PPy/TSA ternary nanocomposite were prepared by chemical oxidative polymerization. The chemical compositions of nanocomposites were characterised by infrared spectrometry and energy dispersive spectroscopy. Micrographs and BET isotherm measurements showed that the particle and the pore size of the ternary nanocomposite are much smaller than those of the binary one. Electrochemical measurements showed that the ternary nanocomposite electrode exhibited a higher specific capacitance of ∼376Fg−1 at 3mAcm−2 and better cycling stability in 0.5M Na2SO4 solution than the binary one, which is attributed to that the dispersed MnO2 particles adhered to PPy chains increase the specific surface area of the ternary nanocomposite and retard the structural deterioration of PPy backbones during charge–discharge cycling process. Long cyclic measurements showed that the specific capacitance of ternary composite can retain 90% of its initial value over 500 charge–discharge cycles in the potential range of −0.1 to 0.9V vs. SCE. Nevertheless, the dispersed MnO2 could reduce the rate capability and conductivity of the ternary composite. [Copyright &y& Elsevier]

Abstract: The interaction between biliverdin and bovine serum albumin (BSA) has been studied by steady fluorescence spectroscopy, synchronous fluorescence and resonance light scanning spectra. The binding of biliverdin to BSA quenches the tryptophan residue fluorescence and the results show that both static and dynamic quenching occur together with complex formation. The binding constant and binding sites of biliverdin to BSA at pH 7.1 are calculated to be 3.33×108 L/mol and 1.54, respectively, according to the double logarithm regression curve. In addition, the distance between the biliverdin and BSA is estimated to be 1.25nm using Föster''s equation on the basis of the fluorescence energy transfer. Furthermore the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues has not obvious changes, which obeys the phase distribution model. Finally, the thermodynamic data show that biliverdin molecules enter the hydrophobic cavity of BSA via hydrophobic interaction. [Copyright &y& Elsevier]

In this paper we report on the low temperature phosphorescence (LTP), the low temperature fluorescence (LTF), the paper substrate room temperature phosphorescence (PS-RTP), and the room fluorescence (RTF) properties of ciprofloxacin (CPFX), lomefloxacin (LMX), fleroxacin (FLX), and ofloxacin (OFLX), which were investigated and compared. Some rules were discovered: their maximal excitation wavelength and emission wavelength are in the range of 280–295 nm and 428–500 nm, respectively, except OFLX, and the difference in molecular structure may be responsible for it. The pH experiments show that all their emissions are strongest in acid, followed by neutral, and weakest in alkali medium. The PS-RTP characters of lifetime and polarization were also investigated and compared. It was found that the lifetimes of PS-RTP were all in the level of 0.1 s. These quinolones belong to long-life phosphorescence and their PS-RTP spectra are incompletely polarized. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between 3,3-bis(4-hydroxy-1-naphthyl)-phthalide (NPP) and bovine serum albumin (BSA) have been studied by fluorescence spectroscopy. The binding of NPP quenches the BSA fluorescence. By the fluorescence quenching results, it was found that the binding constant K =5.30×104 Lmol−1, and number of binding sites n =0.9267. In addition, according to the synchronous fluorescence spectra of BSA, the results showed that the fluorescence spectra of BSA mainly originate from the tryptophan residues. Finally, the distance between the acceptor NPP and BSA was estimated to be 1.94nm using Föster''s equation on the basis of fluorescence energy transfer. The interaction between NPP and BSA has been verified as consistent with the static quenching procedure and the quenching mechanism is related to the energy transfer. [Copyright &y& Elsevier]

Abstract: In this paper, the low-temperature phosphorescence (LTP), the low-temperature fluorescence (LTF), the paper substrate room-temperature phosphorescence (PS-RTP) and the room fluorescence (RTF) properties of caffeine (CF), theophylline (TP), and theobromine (TB) are investigated and compared, and some rules are found out: their maximal excitation wavelength and emission wavelength are in the range of 270–300nm and 395–445nm, respectively. And the PS-RTP characters of lifetime, polarization and quanta yield are also investigated and compared. It is found that their lifetimes of PS-RTP are all in the level of 0.1s. They belong to long-life phosphorescence and their PS-RTP spectra are incompletely polarized. [Copyright &y& Elsevier]

The inclusion complexes of β-cyclodextrin (β-CD) and HP-β-cyclodextrin (HP-β-CD) with caffeine, theophylline and theobromine were investigated by fluorimetry. Various factors affecting the formation of inclusion complexes were discussed in detail including forming time, pH effect and temperature. The results indicate that inclusion process was affected seriously by laying time and pH. The forming time of β-CD inclusion complexes is much longer than that of HP-β-CD. The optimum pH range is about 7–12 for caffeine, 8–10 for TP, 10.5–12 for TB. The intensities of their fluorescence increase with the decreasing of temperature. Their maximum excitation wavelengths are all in the range of 280–290 nm. The emission wavelength of caffeine and theophylline are both in the range of 340–360 nm, and that of theobromine is about 325 nm. The fluorescence signals are intensified with the increasing concentration of CD. The stoichiometry of the inclusion complexes of CD with these three methyl xanthine derivatives are all 1:1 and the formation constant are all calculated. [Copyright &y& Elsevier]

The structures, semiconductor and photocurrent response properties of three 1,4-diazabicyclo[2.2.2]octane derivative-templated iodobismuthates, (Et2DABCO)3(BiI6)2 (1), (i-Pr2DABCO)2(Bi2I10) (2), [(Me2DABCO)2(Bi2I10)2]n (3) (Et2DABCO2+ = N,N′-diethyl-1,4-diazabicyclo[2.2.2] octane, i-Pr2DABCO2+ = N,N′-diisoproyl-1,4-diazabicyclo[2.2.2] octane, Me2DABCO2+ = N,N′-dimethyl-1,4-diazabicyclo[2.2.2] octane), are reported. Based on the templates with different substitutents on 1,4-diazabicyclo[2.2.2]octane, mono-nuclear ((BiI6)3− for 1), dimer ((Bi2I10)4− for 2) and 1-D chain ((BiI5)n2n− for 3) can be obtained. C-H···I hydrogen bonds contribute to the structural extension to 2-D layer (for 2) and 3-D network (for 3). Their absorption spectra were investigated, and energy band gaps of 2.24/1.73/1.44 eV indicate their narrow-gap semiconductor natures. Their photocurrent response properties were also discussed. Finally, theoretical calculation was executed to give structure-properties correlation. [ABSTRACT FROM AUTHOR]

Abstract: The spectral characteristics of four fluorescent dyes: tetrabromofluorescein (TBF), tetrachlorotetrabromofluorescein (TTF), lissamine rhodamine RB 200 (LSR) and methylene violet (MV) were studied by fluorescence and paper substrate room temperature phosphorescence (PS-RTP) methods. The factors affected the luminescence were investigated including pH value, paper substrate and drying conditions, etc. The fluorescence polarizations and PS-RTP lifetimes of these compounds were obtained. The intensity of fluorescence and phosphorescence of TBF and TTF increased in the presence of DNA. Contrarily, that of LSR and MV decreased. The fluorescence quenching and polarization studies indicate that TTF, LSR and MV intercalate into DNA base pairs. In addition, the interaction of TBF with DNA is the comprehensive interaction of two modes: intercalation and groove binding. It was also found that ionic strength could affect the binding of fluorescent dyes and DNA. [Copyright &y& Elsevier]

Dietary preferences were closely associated with the pathogenesis of numbers of metabolic disorders, in particularly, obesity. Dietary fiber was shown to be capable of preventing weight gain and excessive food intake mainly through stimulating chewing and saliva secretion, and promote satiety signals. In this study, we characterized the "Vitamin World® Vegan Meal" Formula of Feihe, a novel protein‐enriched fiber dietary supplement contained potato protease inhibitor II (PI2) that developed. And we demonstrated that this particular fiber formula was effective in preventing weight gain, increasing satiety signals, and reducing food intake in rats in a dosage‐dependent manner. Our study provides lines of evidence and would further bolster the use of this nutritious vegan meal in regulating satiety and food intake in clinics. [ABSTRACT FROM AUTHOR]

[Display omitted] • 12 new diterpenoids were isolated from Pedilanthus tithymaloides. • Compounds 1 – 3 characterize an unusual tricyclo[10.3.0.02,9]pentadecane skeleton. • Compounds 4 – 8 are rare examples of the jatrophanes bearing a cyclic hemiketal substructure. • Compounds 1 – 12 dramatically reversed multidrug resistance in cancer cells. • Compounds 2 and 3 inhibited the P-glycoprotein (Pgp) transporter function. Three new diterpenoids with an unusual carbon skeleton, pedilanins A-C (1 – 3), and nine new jatrophane diterpenoids, pedilanins D-L (4 – 12), along with five known ones (13 – 17), were isolated from Pedilanthus tithymaloides. Compounds 1 – 3 characterize an unprecedented tricyclo[10.3.0.02,9]pentadecane skeleton. Compounds 4 – 8 are rare examples of the jatrophanes bearing a cyclic hemiketal substructure. Their structures were determined by an extensive analysis of HRESIMS, NMR, quantum-chemical calculation, DP4+ probability, and X-ray crystallographic data. In the bioassay, compounds 1 – 12 dramatically reversed multidrug resistance in cancer cells with the fold-reversals ranging from 17.9 to 396.8 at the noncytotoxic concentration of 10 μ M. The mechanism results indicated that compounds 2 and 3 inhibited the P-glycoprotein (Pgp) transporter function, thus reversing the drug resistance. [ABSTRACT FROM AUTHOR]

Background: Both hydrogen sulphide (H2S) and mild hypothermia have been reported to prevent brain damage caused by reperfusion assault through regulating the N-methyl-D-aspartate receptor (NMDAR). However, the relationship between the two treatments and how they exert neuro-protective effects through NMDARs remain to be elucidated. Methods: Transient cerebral ischemia was induced using the Pulsinelli four-vessel occlusion method. We used sodium hydrosulphide (NaHS) as the H2S donor. We randomly divided 100 Sprague-Dawley rats into five groups of 20: Sham operation group (Sh), normothermic (36-37 °C) ischemia group (NT), mild hypothermic (32-33 °C) ischemia group (mHT), normothermic ischemia combined with NaHS treatment group (NT + NaHS), and mild hypothermic ischemia combined with NaHS treatment group (mHT + NaHS). After 6 hrs of reperfusion, rats were decapitated and hippocampus samples were immediately collected. We measured NR2A (GluN1), NR2B (GluN2) and p-CREB protein levels using western blotting. We further analyzed BDNF mRNA expression by real-time PCR. Hematoxylin and eosin (HE) staining was used to examine pyramidal cell histology at the CA1 region. All statistical analyses were carried out by ANOVA and LSD t-test as implemented by the SPSS 13.0 software. Results: In the four test groups with ischemia-reperfusion, hippocampal H2S concentration increased following treatment, and administration of NaHS further increased H2S levels. Moreover, administration of both NaHS and mild hypothermia resulted in up-regulation of NR2A and NR2B protein expressions, as well as p-CREB protein and BDNF mRNA levels. At the cellular level, NaHS and mild hypothermia groups exhibited lower damage caused by ischemia-reperfusion in the CA1 region of the hippocampus. The strongest protective effect was observed in rats treated with combined NaHS and mild hypothermia, suggesting their effects were additive. Conclusion: Our results support previous findings that hydrogen sulphide and mild hypothermia can prevent ischemia-reperfusion injury. Both treatments caused an up-regulation of NMDA receptors, as well as an elevation in p-CREB protein and BDNF mRNA levels. Thus, hydrogen sulphide and mild hypothermia may provide neuro-protective effect through activating the pro-survival CREB signaling pathway. [ABSTRACT FROM AUTHOR]

Background: Neuropathic pain (NP) continues to be challenging to treat due to lack of effective drugs. Accumulating evidence elucidated that glia-mediated inflammatory reactions play a pivotal role in the introduction and development of NP. Besides, activation of the c-Jun N-terminal kinase (JNK)/monocyte chemoattractant protein-1 (MCP-1) pathway in astrocytes has been reported to be critical for spinal astrocytic activation and neuropathic pain development after spinal nerve ligation (SNL). Tanshinone IIA, a major active component of a traditional Chinese drug, Danshen, possesses potent immuno-suppressive activities. The present study was undertaken to assess whether intraperitoneal administration of tanshinone IIA sulfonate (TIIAS) has analgesic effect on SNL-induced neuropathic pain and whether the inhibition of astrocytic activation and JNK/MCP-1 pathway is involved in the analgesic effect of TIIAS. Methods: The effects of TIIAS on SNL-induced mechanical allodynia were assessed by behavioral testing. Immunofluorescence histochemical staining was used to detect changes of spinal astrocytes and spinal pJNK expression and localization. Immunofluorescence histochemistry and Western blot analysis were used to quantify the SNL-induced spinal pJNK expression after TIIAS administration. Enzyme-linked immunosorbent assay (ELISA) was used to detect the SNL-induced spinal expression of pro-inflammatory cytokines and MCP-1. Results: Our results indicated that intraperitoneal TIIAS up-regulated the mechanical paw withdrawal threshold (PWT) of NP, while astrocytic activation was suppressed and accompanied by the down-regulation of IL-1β and TNF-α expression, as well as JNK phosphorylation in the spinal dorsal horn. Additionally, the release of MCP-1 was dose dependently decreased. After co-treatment with TIIAS and JNK inhibitor (SP600125), no significant increases in mechanical PWT and MCP-1 expression were observed compared with the TIIAS-treated group. Conclusions: The present results suggest that the analgesic effects of TIIAS in neuropathic pain are mainly mediated by the down-regulation of SNL-induced astrocytic activation, which is via the inhibition of JNK/MCP-1 pathway. [ABSTRACT FROM AUTHOR]