Two Methods for Intercalation of Surfactants into Graphite Oxide.

The intercalation properties of graphite oxide are important; however, the specific processes and mechanisms associated with intercalation have rarely been elucidated. In this paper, two types of surfactants, polyvinylpyrrolidone and tetradecyltrimethylammonium bromide, were used to thoroughly explore the intercalation properties of graphite oxide. The polyvinylpyrrolidone and tetradecyltrimethylammonium bromide-intercalated graphite oxide composites were synthesized under different conditions and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, and transmission electron microscopy. It was found that polyvinylpyrrolidone could be directly intercalated into the graphite oxide layers and tetradecyltrimethylammonium bromide could not effectively react with the waterdispersed graphite oxide. With a low quantity of polyvinylpyrrolidone, only a part of the graphite oxide was intercalated, and the interlayer spacing of the polyvinylpyrrolidone-intercalated composites increased as the polyvinylpyrrolidone: graphite oxide mass ratio increased. When the graphite oxide was dispersed in a 0.05 N NaOH solution, the tetradecyltrimethylammonium bromide rapidly reacted with the graphite oxide, while the mixture of polyvinylpyrrolidone and graphite oxide could not be effectively separated. The intercalated spacing of the tetradecyltrimethylammonium bromideintercalated graphite oxide increased with the tetradecyltrimethylammonium bromide: graphite oxide mass ratio, but its crystalline structure was not as ordered as the polyvinylpyrrolidone-intercalated graphite oxide prepared in the water solution. The infrared spectra of the two surfactant-intercalated graphite oxide samples revealed that the polyvinylpyrrolidone is bonded to the graphite oxide via hydrogen bonding, while the tetradecyltrimethylammonium bromide is bonded via ionic bonding. The mechanism analysis indicated that the polyvinylpyrrolidone could directly enter the graphite oxide layers in the water solution because of the driving force of hydrogen bonding. However, processes such as graphite oxide exfoliation, reactions between the graphite oxide and tetradecyltrimethylammonium bromide, and reaggregation of the graphite oxide sheets are necessary for the formation of tetradecyltrimethylammonium bromide-intercalated graphite oxide.

Impact of TLR5 rs5744174 on stroke risk, gene expression and on inflammatory cytokines, and lipid levels in stroke patients.

Many studies reported that toll-like receptors (TLRs) played an important role in the process of ischemic stroke (IS). However, the impact of TLR5 rs5744174 on stroke risk, gene expression and on inflammatory cytokines, and lipid levels in ischemic stroke patients has not yet been reported and was therefore the subject of this study. In this case-control study, a total of 816 ischemic stroke patients and 816 healthy controls were genotyped using Sequenom MassArray technology. The mRNA expression of TLR5 was detected through quantitative real-time PCR among 52 ischemic stroke patients. The levels of IL-1b, IL-6, IL-8, and TNFα were measured by ELISA among 62 IS patients. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were determined among 816 IS patients using a Hitachi 7600 Automatic Biochemistry Analyzer. Our result showed TLR5 rs5744174 polymorphism was not associated with stroke risk, TLR5 mRNA expression and inflammatory cytokines of IS patients (P > 0.050), but was significantly associated with HDL-C (recessive model: ß = - 0.14, 95 % CI: -0.24 to -0.03, P = 0.009). TLR5 rs5744174 polymorphism may have no impact on the stroke risk, gene expression and inflammatory cytokines, but may influence the HDL-C serum level of IS patients in Chinese Han population.

TNF-a (-238G/A and -308G/A) gene polymorphisms may not contribute to the risk of ischemic stroke.

BACKGROUND: The common and major pathological change in ischemic stroke is atherosclerosis in the artery. Tumor necrosis factor-a (TNF-a) is closely related to the pathogenesis of atherosclerosis. The aim of our study was to investigate whether TNF-a gene variants (-238G/A and -308G/A) are associated with ischemic stroke. METHODS: A total of 619 ischemic stroke patients and 612 controls were recruited to estimate the frequencies of two TNF-a (-238G/A and -308G/A) single nucleotide polymorphisms using a Sequenom MassARRAY time-of-flight mass spectrometer. The association between TNF-a gene polymorphisms and ischemic stroke risk was evaluated by computing the odds ratio (OR) and 95% Confidence Interval with multivariate unconditional logistic regression analyses. RESULTS: The OR results indicated that no significant associations were found between TNF-a gene (-238G/A and -308G/A) polymorphisms and the risk of ischemic stroke using five genetic models, including the allele model (A vs. G), co-dominant model 1 (GA vs. GG), co-dominant model 2 (AA vs. GG), the dominant model (AA+GA vs. GG), and the recessive model (GG+GA vs. AA). CONCLUSIONS: The TNF-a (-238G/A and -308G/A) gene polymorphisms may not be a susceptible predictor of ischemic stroke in Chinese populations.

Manufacturing a durable superhydrophobic polypropylene coating on aluminum alloy substrate by adding nano-titania nanoparticles.

A superhydrophobic polypropylene (PP) coating on the surface of aluminum alloy coupons is unstable because of the existence of metastable state in curing process. Nano-titania particles were added into PP solution to form hierarchical micro- and nano-structures of PP coatings on the surface of aluminum alloy coupons. The morphology of the coatings was observed with Scanning Electron Microscopy (SEM), and the corresponding structure and components were investigated with Energy Dispersive Spectrometer (EDS) and X-ray diffractometer (XRD), respectively. The results indicated that nano-TiO2 particles are the main nucleation cores in the curing of the coatings; PP in solution is enclosed in these cores and crystallizes gradually. The coatings can preserve the stable micro- and nano-structure on six months due to the nucleation action of nano-TiO2 particles, and its durable water contact angle (WCA) is about 164 +/- 1.5 degrees.

Study on the preparation and enzyme inhibitory activity of polyphenols from Sargassum pallidum.

This study aimed to obtain a high yield and purity of Sargassum pallidum polyphenol extracts (SPPE) and study its enzyme activity. Fresh Sargassum pallidum seaweed was selected for optimization of ultrasound-assisted extraction (UAE) conditions and purification conditions using macroporous resin and Sephadex LH20 to obtain SPPE. The SPPE was characterized using UPLC-QTOF-MS/MS and α-amylase, α-glucosidase, tyrosinase, and AchE inhibitory activity were determined. The maximum extraction rate of SPPE was 7.56 mg GAE/g and the polyphenol purity reached 70.5% after macroporous resin and Sephadex LH-20 purification. A total of 50 compounds were identified by UPLC-QTOF-MS/MS. The IC50 values of SPPE were 334.9 µg/mL, 6.290 µg /mL, 0.834 mg /mL and 0.6538 mg /mL for α-amylase, α-glucosidase, tyrosinase and AchE, respectively. Molecular docking technology further revealed the effects of SPPE on the above enzymes. This study provided information on the potential hypoglycemic, whitening and anti-Alzheimer's disease biological activities of SPPE, which had guiding significance for the purification and development of other seaweed polyphenols.

Preparation of micro/nano-structure superhydrophobic film on aluminum plates using galvanic corrosion method.

A simple and novel approach has been developed to obtain a microporous film with compound nanoparticles on the surface of aluminum alloy substrate using the galvanic corrosion method. The wettability of the surface changes from hydrophilicity to superhydrophobicity after chemical modification with stearic acid (SA). The water contact angle (WCA) and sliding angle (WSA) of superhydrophobic aluminum alloy surface (SAAS) are 154 degrees and 9 degrees, respectively. The roughness of the aluminum substrate increases after the oxidation reaction. The porous aluminum matrix surface is covered with irregularly shaped holes with a mean radius of about 15 microm, similar to the surface papillae of natural Lotus leaf, with villus-like nanoparticles array on pore surfaces. The superhydrophobic property is attributed to this special surface morphology and low surface energy SA. X-ray powder diffraction (XRD) pattern and Energy Dispersive X-Ray Spectroscopy (EDS) spectrum indicate that Al2O3, Al(OH)3 and AIO(OH) has been formed on the surface of aluminum substrate after the oxidation reaction. The Raman spectra indicate that C-H bond from SA and the Al-O are formed on the SAAS. The as-formed SAAS has good stability.

The Preparation, Structural Design, and Application of Electroactive Poly(vinylidene fluoride)-Based Materials for Wearable Sensors and Human Energy Harvesters.

Owing to their biocompatibility, chemical stability, film-forming ability, cost-effectiveness, and excellent electroactive properties, poly(vinylidene fluoride) (PVDF) and PVDF-based polymers are widely used in sensors, actuators, energy harvesters, etc. In this review, the recent research progress on the PVDF phase structures and identification of different phases is outlined. Several approaches for obtaining the electroactive phase of PVDF and preparing PVDF-based nanocomposites are described. Furthermore, the potential applications of these materials in wearable sensors and human energy harvesters are discussed. Finally, some challenges and perspectives for improving the properties and boosting the applications of these materials are presented.

Preparation, Chromatic Properties Analysis and Proportioning Optimization of Co-Cr-Fe-Based Black Pigment.

The utilization of Co-Cr-Fe-based black pigments bears considerable significance within the realm of commercial ceramic pigments, owing to their distinctive spinel structure, remarkable high-temperature stability, and exceptional chromatic attributes. This study delves into the synthesis of diverse black pigment configurations by employing the co-precipitation method, leveraging the interplay of these three metallic oxides. This investigation encompasses a comprehensive scrutiny of ion valences, crystal structures and parameters, colorimetric properties, and their interrelationships. The methodology integrates the response surface methodology (RSM) framework, using theoretical formulations to navigate the material ratios and elucidating the associations between the resultant compositions and color coordinate values, aligned with the CIE-Lab* colorimetric methodology. The derived predictive models yielded an optimized black pigment composition, characterized by heightened black intensity and a refined formulation.

[Simultaneous determination of 40 plant growth regulators, fungicides, insecticides, and antibiotics in bean sprouts by QuEChERS-high performance liquid chromatography-tandem mass spectrometry].

Chromatography combined with mass spectrometry is the most commonly used detection technology, and it offers the advantages of high sensitivity and high selectivity. The quick, easy, inexpensive, effective, rugged, and safe (QuEChERS) method is low-cost, effective, and time efficient. The application of the QuEChERS has now been extended to the analysis of contaminants in food samples. The aim of the study was to identify different concentration levels of multiple harmful drug residues in bean sprouts. In this study, QuEChERS coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established for the simultaneous determination of 40 plant growth regulators, fungicides, insecticides, and antibiotics in bean sprouts. In the HPLC-MS/MS experiment, gibberellic acid, 4-fluorophenoxyacetic acid, chloramphenicol, N6-(δ2-isopentenyl)-adenine, 6-benzylaminopurine, 4-chlorophenoxyacetic acid, and 2,4-dichlorophenoxyacetic acid (2,4-D) were analyzed by MS/MS with negative electrospray ionization (ESI-). The other 33 target analytes (chlormequat, ronidazole, metronidazole, pymetrozine, dimetridazole, methomyl, carbendazim, enoxacin, levofloxacin, pefloxacin mesylate, norfloxacin, ciprofloxacin, enrofloxacin, thiabendazole, lomefloxacin, chlorpyrifos, sarafloxacin, imidacloprid, etc.) were analyzed by MS/MS with positive electrospray ionization (ESI+). Sensitive MS conditions were realized by optimizing the instrumental parameters such as the desolvent temperature, collision energy, spraying needle position, precursor ions, and product ions. Then, the optimal pretreatment method was determined by comparing the recovery rates of the 40 drugs obtained with different extraction solvents (methanol, acetonitrile, acetonitrile containing 0.1% ammonia, acetonitrile with 1% acetic acid), different extraction methods (ultrasonic extraction, shaking extraction), and purification with primary secondary amine (PSA) and C18. In this study, the bean sprouts samples were extracted twice by 10 mL acetonitrile with 1% acetic acid, and extracted under ultrasonic conditions. Then, the extracting solution was only cleaned with 100 mg C18. The chromatographic separation of the 40 compounds was accomplished on a Waters ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 µm) with gradient elution. Methanol and 0.01% formic acid aqueous solution were used as the mobile phases. The 40 compounds were analyzed in the multiple reaction monitoring (MRM) mode. The matrix matching external standard method was used for quantitative determination. The results showed that the 40 compounds could be analyzed within 15 min. Under the optimized conditions, the calibration curves showed good linearities for the 40 compounds, and the coefficients of determination (r2) were greater than 0.99 in the range of 2-200 µg/L. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.1-3 µg/kg and 0.3-9 µg/kg, respectively. Using negative bean sprouts as the substrates, the recovery tests were carried out at three spiked levels of 5, 10, and 50 µg/kg. The average recoveries of the 40 drugs were 78.5% to 115.3%, and the corresponding relative standard deviations (RSDs) were 1.3% to 9.7% (n=6). This method was successfully applied to the analysis of the 40 drug residues in 21 batches of local bean sprouts in Handan city. The results revealed the presence of extensive drug residues in the bean sprouts. The 26 batches were detected to varying degrees, among which 4-chlorophenoxyacetic acid, carbendazim, 6-benzyladenine, 2,4-D, enrofloxacin, and metronidazole were detected at high rates. The detection rates of 4-chlorophenoxyacetic acid, 6-benzyladenine, carbendazim, 2,4-D, gibberellic acid, and enrofloxacin were 28.6%, 19.0%, 9.5%, 9.5%, 4.8%, and 4.8%, respectively. The contents ranged from 37.5-352.4, 32.4-273.1, 28.8-38.7, 316.1-20.2, 19.9 and 13.6 µg/kg, respectively. Given its advantages of simplicity, rapidness, and high sensitivity, the developed method can be used for the rapid and accurate determination of trace levels of the 40 drug residues in large quantities of bean sprouts.

TLR7 rs2897827 Polymorphism Affects TLR7 Gene mRNA Expression and Serum Apolipoprotein A1 Level of Ischemic Stroke Patients in a Chinese Han Population.

Stroke is a multi-factorial disorder that has become the leading cause of death and disability worldwide. Previous studies reported that TLR7 mRNA expression is associated with poor outcome of ischemic stroke (IS). This study aimed to assess whether TLR7 mRNA expression affects IS occurrence, as well as the association of TLR7 rs2897827 with susceptibility to IS and TLR7 mRNA expression and serum apolipoprotein and lipid levels in a Chinese Han population. A total of 816 stroke patients and 816 healthy controls were included in this study. mRNA expression was determined by quantitative real-time PCR. The Sequenom MassARRAY iPLEX platform was used to genotype the TLR7 rs2897827 polymorphism. TLR7 mRNA expression of the IS cases was statistically significantly higher than that of the controls in the male or female group (male, P = 0.014; female, P = 0.025). In the male IS cases, TLR7 mRNA expression of the T allele carriers was statistically significantly higher than that of the C allele carriers (P = 0.018). However, a significant difference was not observed in the female cases (P = 0.545). In either the male or female group, the distribution of genotype or allele had no statistical significance (P > 0.050). The ApoA1 level of the T carriers was statistically significantly higher than the C carriers in males (t = -2.383, P = 0.020); however, the ApoB and lipid levels were not associated with rs2897827 (P > 0.050). In female patients, no significant difference was observed between different genotypic/allelic carriers in serum apolipoprotein and lipid levels (all P > 0.050). The expression of the TLR7 gene may affect IS occurrence. TLR7 gene rs2897827 may influence TLR7 mRNA expression and the plasma ApoA1 level in male IS patients.

Association of TLR8 gene rs3764880 polymorphisms with susceptibility and lipid metabolism- and inflammation response-related quantitative traits of ischemic stroke in southern Chinese Han male population.

Inflammatory response and lipid metabolism influence the development of ischemic stroke (IS). TLRs have an important function in inflammation and lipid metabolism. To investigate association of TLR8 rs3764880 polymorphism with susceptibility of IS and the relationship between rs3764880 with inflammation response- and lipid metabolism-related quantitative traits, we conducted a case-control study in a Han Chinese population comprising 816 cases and 816 controls being matched for age and gender. The distribution of allele of TLR8 rs3764880 had statistical significance in male group (P=0.017). The G allele carrier had a higher level of IL-8 (P=0.001, PBc=0.004) than the A allele carrier in male cases. Moreover, the rs3764880 genotype was significantly associated with TC (P=0.001, PBc=0.004) and LDL level (P=0.0002, PBc=0.0008) in the allele model, and the GG carrier had a higher LDL level (P=0.009, PBc=0.036) than the AA carrier in male patients. However, no statistically significant association was found between rs3764880 and any IS-related quantitative traits in female patients. Our study also revealed that IL-1b was associated with HDL (P=0.006, PBc=0.012) in IS patients. Therefore, TLR8 gene rs3764880 polymorphism might be associated with susceptibility and involved in the inflammatory reaction and lipid metabolism of IS in southern Chinese Han.

Association of GWAS-supported loci rs2107595 in HDAC9 gene with ischemic stroke in southern Han Chinese.

BACKGROUND: Stroke is a multi-factorial disorder and has become the leading cause of death and disability worldwide. Recent genome-wide association studies (GWAS) have identified a significant association of single-nucleotide polymorphism (SNP) rs2107595 in HDAC9 gene with large-vessel ischaemic stroke (IS) in the European populations. The aim of this study is to examine the association of HDAC9 gene rs2107595 polymorphism with the susceptibility of IS in southern Han Chinese. METHODS: A case-control study was conducted in Chinese Han population, with a total of 1632 subjects including 816 stroke patients and 816 controls. Sequenom MassARRAY iPLEX was used to genotype the SNP rs2107595 in HDAC9 gene. Genetic association analysis between genotypes and risk of IS was evaluated by PLINK program. RESULTS: No significant association was found between the SNP rs2107595 and IS in the additive, dominant, recessive and allelic models (all p>0.050). For IS-related quantitative traits in the sex-stratified analysis, the results showed a significant association between rs2107595 and serum TG level of males in the additive model (padj=0.008) and the dominant model (padj=0.003), and a significant association of rs2107595 polymorphism with serum TC level of females in the additive model (padj=0.045) and the dominant model (padj=0.037). CONCLUSIONS: Our results indicate that HDAC9 variant rs2107595 may be not associated with IS risk in southern Han Chinese. However, the rs2107595 polymorphism may be associated with serum TC and TG level of IS patients.

Association between DAOA gene polymorphisms and the risk of schizophrenia, bipolar disorder and depressive disorder.

OBJECTIVE: Schizophrenia (SCZ), bipolar disorder (BD) and depressive disorder (DD) are common psychiatric disorders, which show common genetic vulnerability. Previous gene-disease association studies have reported correlations between d-amino acid oxidase activator (DAOA) gene polymorphisms and the three psychiatric disorders. However, the findings were contradictory. A meta-analysis was therefore conducted to provide more robust investigations into DAOA polymorphisms and the risk of SCZ, BD and DD. METHODS: This meta-analysis recruited 46 published studies up to July 2013, including 17,515 cases and 25,189 controls. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the association between three specific DAOA SNPs and SCZ, BD and DD. Publication bias was tested by Begg's test and funnel plot, and heterogeneity was assessed by the Cochran's chi-square-based Q statistic and the inconsistency index (I(2)). Moreover, the robustness of the findings was estimated by cumulative meta-analysis. RESULTS: DAOA genetic polymorphisms (M15, M18 and M23) were not found to confer a statistically significant increased risk of SCZ, BD or DD in the overall sample, or in Caucasians and Asians following subgroup analysis. CONCLUSION: The current study indicated that M15, M18 and M23 might not be the risk factor for SCZ, BD or DD. However, further studies are required to provide robust evidence to estimate the association between DAOA polymorphisms and psychiatric disorders.

The ABCB1-C3435T polymorphism likely acts as a risk factor for resistance to antiepileptic drugs.

Previous studies have attempted to confirm the association between the ABCB1-C3435T polymorphism and drug-resistant epilepsy and produced discordant findings. A meta-analysis was conducted to assess the role of the C3435T polymorphism in drug-resistance in epilepsy. Databases were obtained from PubMed, Embase, the Chinese Wanfang, CNKI, and Chongqing VIP database, and all relevant studies were compiled up to February 2013. Odds ratios (ORs) were calculated using models of both fixed- and random-effects for comparisons of alleles and genotypes. Subgroup meta-analyses were carried out based on epilepsy subtype, age, therapeutic regimen, definition of drug-responsiveness and drug-resistance using alleles and genotypes models. Publication bias was tested by Begg's test and inverted funnel plot, and heterogeneity was checked by Cochran's Q statistic and the inconsistency index (I2). Cumulative meta-analyses were adopted to test the robustness of the findings. A total of 38 association studies including a total of 8716 subjects, 4037 drug-resistant patients and 4679 drug-responsive epilepsy patients were pooled in this meta-analysis. The association of ABCB1-C3435T with risk of drug-resistance was significant in the overall population (T allele vs. C allele, OR: 1.21; 95%CI: 1.06-1.39; P=0.006) and in Caucasians, adults, groups treated with various drugs, a '>10 seizures in a year' group based on resistance and a '≥2 years seizure free' group based on response subgroup analysis. The ABCB1-C3435T polymorphism is likely to act as a risk factor for resistance to antiepileptic drugs that needs to be confirmed through further studies.