Vertical Scar Reduction Mammaplasty Using the Superomedial-Based Pedicle Technique in Gigantomastia.

BACKGROUND: Breast reduction surgery has witnessed significant advancements in recent years; however, it continues to pose challenges for both surgeons and patients when dealing with cases involving excessive breast volume and severe breast ptosis. This study aimed to assess the aesthetic outcomes and the impact on the quality of life, as measured by the BREAST-Q questionnaire, in patients with gigantomastia and severe breast ptosis who underwent reduction mammaplasty using the superomedial-based pedicle technique. METHODS: We present a retrospective series comprising 84 patients who underwent reduction mammoplasty utilizing the superomedial pedicle technique. The surgical resections exceeded 1 kg per breast, with a mean resection weight of 1506.58 g (right breast) and 1500.32 g (left breast). The preoperative mean suprasternal notch to nipple distance measured 40.50 cm (right breast) and 40.38 cm (left breast). Postoperatively, the patients were followed up for a minimum of 6 months. Both preoperative and postoperative BREAST-Q surveys were administered to the participants, and scores were analyzed using descriptive statistics. RESULTS: Complications were observed in 3 patients (3.57%), characterized by partial loss of the areola, which resolved spontaneously over time. Additionally, 2 cases of hematoma and 2 instances of minor delayed wound healing were reported. All patients expressed satisfaction with their aesthetic outcomes, as they achieved a natural breast shape and minimal scarring, along with symptomatic relief. CONCLUSIONS: The superomedial pedicle reduction mammaplasty technique has demonstrated its ability to produce satisfactory aesthetic outcomes and long-term benefits in patients with excessively large breasts. Careful patient selection and postoperative management are vital for achieving optimal results. Further investigations involving larger sample sizes and longer follow-up periods are warranted to validate our findings. LEVEL OF EVIDENCE: IV.

Platelet-Rich Fibrin in Fat Grafts for Facial Lipofilling: A Randomized, Controlled Split-Face Clinical Trial.

Objective: Previous studies have reported that platelet-rich fibrin (PRF) may enhance the efficacy of fat grafts in facial lipofilling. However, these studies either lacked objective data or were not randomized, controlled trials. Thus, we aimed to objectively evaluate the efficacy of PRF in facial lipofilling. Methods: A controlled, split-face, randomized trial (January 2018 to May 2019) based on 18 patients who underwent fat grafts for bilateral temple lipofilling was performed. Each patient received a combination of an autologous fat graft and PRF on one side and a fat graft combined with an equal volume of saline on the other side. The effects of PRF were evaluated by comparing the remaining bilateral fat graft volumes through a digital three-dimensional reconstruction technique. Improvements in the appearance and recovery time of each temple were assessed by both a surgeon and patients who were blinded to the treatment assignment. Complications were also recorded. Results: Bilateral temple lipofilling showed no evidence of fat embolism, vascular/nerve injury, infection, massive edema, or prolonged bruising. Three-dimensional reconstruction data and the assessments from both the surgeon and patients revealed no significant differences in fat graft retention volume between the PRF-positive and PRF-negative lipofilling groups. However, recovery time in the PRF-positive lipofilling sites was significantly shortened compared with that of the PRF-negative lipofilling sites. Conclusion: Facial filling with autologous fat grafts is effective and safe. Our results show that PRF does not markedly improve fat graft volume retention in the temple but significantly reduces postoperative recovery time. Trial Registration Number: ChiCTR2100053663.

Response of salinity gradient power generation to inflow mode and temperature difference by reverse electrodialysis.

Sustainable utilization has been becoming the core idea of concentrated seawater disposal, which makes the harvest of salinity gradient power based on reverse electrodialysis (RED) become one of the important ways. As the important factors affecting RED performance, different flow orientations along the membrane and solution temperature have been studied in the previous researches. However, there are still some details that need to be clarified. In this study, the inflow mode was further detailed investigated. The results showed that after eliminating the interference of bubbles in the counter-current, the co-current was still better than the counter-current; when the solution of HCC (high concentration compartment) and LCC (low concentration compartment) was circulated for 3 h, the concentration of concentrated seawater discharge liquid was reduced by 6.93%, which was conducive to reducing the negative impact on the marine ecological environment. Meanwhile, the response of salinity gradient power generation to temperature difference was that high temperature had a positive effect on power density, and the order was both the HCC and LCC (0.44 W m-2) > LCC (0.42 W m-2) > HCC (0.39 W m-2). Although the RED performance was more sensitive to the temperature rise of LCC, the positive temperature difference between HCC and LCC is a more practical advantage because the temperature of concentrated seawater in HCC is usually high. These new observations could provide supports for the industrial development of RED in generating electricity economically and reducing the negative environmental impact of concentrated seawater.

Wetting Behavior and Tribological Properties of Polymer Brushes on Laser-Textured Surface.

Polymer brush layers can act as effective lubricants owing to their low friction and good controllability. However, their application to the field of tribology is limited by their poor wear resistance. This study proposes a strategy combining grafting and surface texturing to extend the service life of polymer brushes. Surface microstructure and chemical composition were measured through scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Water contact angles were measured to evaluate the surface wettability of the grafted silicon-based surface texture. Results showed the distinct synergistic effect between polymer brushes and laser surface texturing (LST). The prepared polymer brushes on textured surface can be a powerful mechanism for friction reduction properties, which benefit from their strong hydration effect on the lubrication liquid and promote the formation of a local lubricating film. Moreover, the wear life of polymer brushes can be immensely extended, as micro-dimples on the textured surface can effectively protect the polymer brushes. This study presents a method to enhance the load-bearing capacity and wear resistance of the grafted surface of polymer brushes.

CTLA-4 polymorphisms and systemic lupus erythematosus (SLE): a meta-analysis.

The aim of this study was to summarize results on the association of cytotoxic T-lymphocyte antigen-4 (CTLA-4) promoter exon-1 +49 and 1722T/C polymorphism with systemic lupus erythematosus (SLE) susceptibility by using the meta-analysis. We searched all the publications about the association between CTLA-4) promoter exon-1 +49 and 1722T/C polymorphism and SLE from PubMed, Elsevier Science Direct, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), and Wanfang (Chinese). Previous CTLA-4 association studies with SLE, however, have produced inconsistent results. We have performed a meta-analysis to better assess the purported associations. A total of 17 independent studies (to June 2012) testing association between one or more CTLA-4 polymorphisms and SLE were used in this analysis. We have compared allele and genotype frequencies at two polymorphic sites found in exon-1 (at +49) and the promoter region (at -1722). The data demonstrate that the exon-1 +49 polymorphism is associated with SLE susceptibility in Asian population. The overall risk, measured by odds ratio (OR), stratification by ethnicity indicates the exon-1 +49 GG+GA genotype is associated with SLE, at least in Asians (OR = 0.85, 95 % CI = 0.73-0.99, P = 0.04 for GG+GA vs. AA; OR = 0.85, 95 % CI = 0.72-1.00, P = 0.05 for AG vs. AA). Similar trends are found in allele-specific risk estimates and disease association. Overall, there was significant association between the 1722T/C polymorphism and overall SLE risks (OR = 0.78, 95 % CI = 0.63-0.97, P = 0.04 for GG+GA vs. AA, OR = 0.87, 95 % CI = 0.76-0.99, P = 0.04 for G vs. A) in Asian population.In summary, this meta-analysis demonstrates that the CTLA-4 promoter +49A/G and promoter -1722C/T polymorphism may confer susceptibility to SLE, especially in Asian-derived population.

No association between COMT Val158Met polymorphism and prostate cancer risk: a meta-analysis.

OBJECTIVE: Results from published studies on the association between the catechol-O-methyltransferase (COMT) Val158Met polymorphism and prostate cancer (PCa) risk are inconsistent. To derive a more precise estimate, we performed a meta-analysis. METHODS: We searched in the PubMed and Elsevier Science Direct database for studies on the association between the COMT Val158Met polymorphism and PCa. We used the odds ratio with 95% confidence interval for PCa risk, detected potential sources of heterogeneity with the Chi-square-based Q-test, performed sensitivity analysis of studies adapted to the Hardy-Weinberg equilibrium. RESULTS: We found seven case-control studies included 2292 patients and 2158 controls. Fix-effects meta-analysis failed to explore any significant association of PCa with the genetic model and the allelic model of COMT Val158Met. We also did not detect any association in the subgroup analysis by ethnicity in all genetic models. The gene-based analysis suggested that the genetic polymorphism in COMT is not associated with PCa. CONCLUSIONS: There is no association between the COMT Val158Met polymorphism and PCa.

Quantification of domoic acid in shellfish samples by capillary electrophoresis-based enzyme immunoassay with electrochemical detection.

A new method was developed to quantify domoic acid by capillary electrophoresis-based enzyme immunoassay (CE-EIA) with electrochemical (EC) detection. The method was based on noncompetitive immunoreaction between free domoic acid antigen (Ag) and excessive amount of horseradish peroxidase (HRP)-labeled antidomoic acid antibody tracer (Ab*) in liquid phase. Then the bound enzyme-labeled complex (Ab*-Ag) and unbound Ab* were separated by CE, and the system of HRP catalyzing H(2)O(2)/o-aminophenol (OAP) reaction was adopted for EC detection. Using CE-EIA with EC detection, equilibrium was reached in 30 min, and the analytical results were obtained within a further 5 min. The linear range and the detection limit were 0.1-50 ng/mL and 0.02 ng/mL, respectively. Analytes recoveries were 89.6-105.8%. The sensitivity of the method was 16 times greater than that of enzyme-linked immunosorbent assay (ELISA). The developed method was applied to quantitatively analysis of domoic acid in contaminated shellfish samples with rapid and simple pretreatment, and the results were consistent with the same samples analyzed through ELISA. The CE-EIA with EC detection provides a valid and sensitive analytical approach, not previously available, for determination of domoic acid in shellfish samples.

PDTC attenuate LPS-induced kidney injury in systemic lupus erythematosus-prone MRL/lpr mice.

Lipopolysaccharide (LPS) from bacteria can accelerate and exacerbate lupus nephritis (LN) and induce infiltrating inflammatory cells in kidney in animal models. Pyrrolidine dithiocarbamate (PDTC) is known to exert anti-inflammatory effects. Monocyte chemoattractant protein-1(MCP-1) is upregulated by various stimuli, including LPS, high glucose, and hyperosmolality. However, the molecular mechanisms of transcriptional regulation of the MCP-1 protein expression with LPS are poorly understood. Expression of MCP-1 was examined by western blot and enzyme-linked immunosorbent assay, respectively. The activity of nuclear factor (NF)-kappaB was measured by western blot. These mice have uncontrolled proliferation of T cells, an impaired response to T cell mitogen and produce autoantibodies against nuclear antigens, including DNA. We found that after LPS treatment for 14 weeks, LPS increased MCP-1 protein expression in kidney, which was significantly suppressed by antioxidant PDTC. The expression of NF-κB, pERK, pJNK and MCP-1 were increased, pp38 expression was decreased significantly, concomitantly with sera anti-dsDNA, MCP-1 and the acceleration of severity of autoimmune kidney injury. LPS induce markedly neutrophil infiltration in the glomerulus, especially around the mesangial region. PDTC reduced the number of infiltrating inflammatory cells and severity of kidney injury via inhibiting NF-κB and p38 MAPK activity. They also markedly prevented LPS-induced pJNK and MCP-1. Therefore, MCP-1 may be responsible for the recruitment and activation of leukocytes in diseased kidneys in female MRL/lpr mice. In this study, the long-term administration of PDTC had impacts on the prevention of end-stage organ damage induced by LPS treated. We demonstrated that PDTC inhibited LPS-induced monocyte migration and attenuated LPS-induced p38 MAPK activation. Based on these data we infer that PDTC inhibits LPS-induced MCP-1 expression, secretion and function through inhibition of NF-κB and p38 MAPK activity. Our study suggests that MAPK is an important therapeutic target of monocyte recruitment and accumulation within the glomerulus in inflammatory renal disease. These results suggest that PDTC protects against kidney inflammation of SLE at least in part via NF-κB and MAPK signaling pathways induction, and that inhibitory action on anti-dsDNA may be associated with the protective mechanism of PDTC. In summary, PDTC pretreatment attenuates LPS-induced kidney injury in female MRL/lpr mice through regulating NF-κB and MAPK signaling pathways. Our results indicate that LPS induces MCP-1 mainly through activating NF-κB and its downstream MAPK, and that such effect was inhibited by PDTC, suggesting the efficacy of PDTC in preventing kidney fibrosis in lupus-prone mice. Therefore, appropriate inhibition of NF-κB activation may attenuate the kidney injury in lupus-prone mice.

[Studying the lipid peroxidation index, morphology and apoptosis in testis of male BALB/c mice exposed to polybrominated diphenyl ether (BDE-209)].

OBJECTIVE: To explore the lipid peroxidation and the testicular morphological change induced by decabrominated diphenyl ether (BDE-209) in male BALB/c mice. METHODS: Twenty one male BALB/c mice were randomly divided into three groups: the high exposure group (500 mg/kg BDE-209), the low exposure group (200 mg/kg BDE-20) and control group (normal saline). The mice were exposed by gavage one time a day for 6 weeks, then were sacrificed. Body weight, testis weight, malonyldialdehyde (MDA), total superoxide dismutase (T-SOD) and glutathione (GSH) in testis were examined. The morphological alteration of testis was observed. TUNEL assay was used to detect the apoptosis in testicular cells. RESULTS: Body weight and testis weight in high and low exposure groups were (21.6140 +/- 2.3550) g, (20.8000 +/- 1.7630) g and (0.1859 +/- 0.0349) g, (0.1718 +/- 0.0266) g, respectively, which were significantly lower than those (27.7570 +/- 1.2880) g and (0.2302 +/- 0.0335) g in the control group (P < 0.05); the testis coefficient in high exposure group was (0.8640% +/- 0.1706%), which was significantly higher than that (0.8329 +/- 0.1386%) in the control group (P < 0.05). The GSH level and SOD activities of testis in 2 BDE-209 groups were 0.044 +/- 0.006, 0.039 +/- 0.005 nmol/mg prot, and 0.735 +/- 0.179, 0.907 +/- 0.198 U/mg prot, respectively, which were significantly lower than those (0.052 +/- 0.067) mol/mg and (1.161 +/- 0.188) U/mg in the control group (P < 0.05). The levels of MDA in 2 BDE-209 groups were (2.365 +/- 0.339) and (1.752 +/- 0.366) nmol/mg prot, which were significantly higher than that (1.173 +/- 0.232 nmol/mg prot) in control group (P < 0.05). there were significant differences of SOD and MDA levels between high exposure group and low exposure group (P < 0.05). Histological examination showed that the number of spermatogenic cells and layer were decreased significantly in 2 exposure groups as compared with control group. TUNEL assay showed that apoptosis cells appeared in 2 exposure groups. CONCLUSION: BDE-209 changed lipid peroxidation in male BALB/c mice testis and caused toxic effects on the testis.

[Effects of mitogen-activated protein kinases signaling pathway proteins on kidney injury in mice exposed subchronically to cadmium].

OBJECTIVE: To explore the effects of mitogen activated protein kinase (MAPK) and extracellular signal-regulated kinases (ERK) on kidney injury in female BALB/c mice exposed to cadmium. METHOD: Twenty-one female BALB/c mice were randomly divided into 3 groups, i.e. control group, low Cd exposure group (2.5 µmol/kg) and high Cd exposure group (10 µmol/kg) were exposed to normal saline, 2.5, 10 µmol/kg Cd, respectively, 3 times a week for 14 weeks. The kidney slice were stained by HE, PAS and Masson staining to observe the morphological changes. The expression levels of pERK, ERK, pp38, p38, pJNK and JNK proteins in kidneys were tested by Western blot assay. RESULTS: The ratios of pERK/ERK, pp38/p38, pJNK/JNK in high Cd group were higher than those in the control group (P < 0.05). The ratio of pERK/ERK in low Cd group was higher than control group (P < 0.05). The expression levels of bcl-2, bax proteins and the ratio of bcl-2 to bax in Cd exposure groups decreased significantly, as compared with the control group (P < 0.05). The impairment of renal glomeruli and tubules were observed in HE, PAS and Masson staining slices of kidneys in mice exposed to Cd. CONCLUSION: CdCl2 may induced renal injury by affecting the expression levels of MAPK.

[Effect of exposure to higher decabrominated diphenyl ether (PBDE-209) on learning and memory functions of BALB/c mice].

OBJECTIVE: To investigate the effects of exposure to decabrominated diphenyl ether (PBDE-209) on learning and memory of BALB/c mice. METHODS: Eighteen female BALB/c mice were randomized divided into 3 groups and gavaged with peanut oil in the control groups and 300, 1500 mg x kg(-1)xd(-1) PBDE-209 in peanut oil daily in two exposed groups respectively for 4 weeks. The learning and memory ability of mice were tested by the Morris water maze and the shuttling box respectively. The body weight and organs index were measured and the acetylcholinesterase and butyrylcholinesterase activity in brain were determined. The liver histopathological examination was performed. RESULTS: The heart index in high dose PBDE-209 group was higher than that of the low dose PBDE-209 group (P < 0.05). The results of Morris water maze showed that escape latency period was significantly shorter than the control group (F = 3.134, P < 0.05). The swimming time in the second quadrant of low dose PBDE-209 group was (15.78 +/- 10.92) s, significantly shorter compared with the swimming time in the second quadrant of the control group's [(28.80 +/- 8.67) s] (P < 0.05). There was no significant difference in the times of active avoidance in the shuttling between three groups (F = 3.423, P = 0.06). There were no significant differences in acetylcholinesterase and butyrylcholinesterase activity in brain of PBDE-209 groups compared with the control group (P > 0.05). Histologically liver damages in structure such as adipose degeneration and swelling were observed in PBDE groups. CONCLUSION: Exposure to PBDE-209 slightly impairs the space learning and memory ability of BALB/c mice, and it has some hepatotoxicity.

[Oxidative stress of decabromodiphenylether in mice brain tissue].

OBJECTIVE: To study the oxidative stress induced by decabromodiphenylether (PBDE-209) in the cerebral cortex, hippocampus, cerebellum and striatum of mice. METHODS: Twenty-eight male BALB/c mice were randomized divided into four groups with seven mice in each: solvent control, blank control, low (200 mg/kg) and high (500 mg/kg) dose groups. Test substances were administered by gavage and mice were sacrificed 6 weeks after treatment. Malonyldialdehyde (MDA), total superoxide dismutase (T-SOD) and glutathione (GSH) in cerebral cortex, hippocampus, cerebellum and striatum were examined. RESULTS: The content of MDA in cerebral cortex, cerebellum, striatum and hippocampus in high dose group was (92.25 ± 36.64), (4.24 ± 1.15), (12.92 ± 4.30), (12.12 ± 6.39) nmol/mg pro respectively, higher than that in blank group [(56.713 ± 6.44), (2.42 ± 1.41), (4.05 ± 2.23), (4.91 ± 1.60) nmol/mg pro] and the difference was statistically significant (P < 0.05); T-SOD activity in cerebral cortex, cerebellum and striatum in low dose group was (182.48 ± 11.59), (6.67 ± 1.56), (35.48 ± 21.98) U/mg pro respectively, lower than that in blank group [(277.76 ± 106.70), (18.02 ± 16.40), (63.57 ± 20.83) U/mg pro] and the difference was statistically significant (P < 0.05); in high dose group the T-SOD activity in hippocampus was(59.26 ± 37.09) U/mg pro, lower than that in blank group [(93.28 ± 21.75) U/mg pro] and the difference was statistically significant (P < 0.05); The content of GSH in cerebral cortex, cerebellum and striatum in high dose group was (40.98 ± 13.19), (3.55 ± 1.55), (24.46 ± 11.30) mg/g pro respectively, lower than that in blank group [(75.79 ± 26.51), (8.01 ± 3.23), (44.52 ± 13.15) mg/g pro and the difference was statistically significant (P < 0.05); while the content of GSH in hippocampus was not decreased significantly compared with the blank group (P > 0.05). CONCLUSION: PBDE-209 could induce oxidative stress in nervous tissue. The tissue oxidative damage might be one of the primary mechanisms of neurotoxicity of PBDE-209.

Online preconcentration and two-dimensional separation of cationic compounds via hyphenation of capillary zone electrophoresis with cyclodextrin-modified micellar electrokinetic capillary chromatography.

A novel preconcentration/separation approach, which online combined CZE with CD-modified MEKC, was developed for simultaneous enhancing resolving power and detection sensitivity. CZE with cation-selective exhaustive injection and transient ITP preconcentration was used as the first dimension, from which the effluent fractions were further analyzed by CD-modified MEKC acting as the second dimension. As the key to successful integration of CZE with MEKC, a new interface was designed and electroaccumulation focusing strategy was employed to avoid analyte band diffusion at the interface. The comprehensive 2-D system was successfully established with only one high voltage and four electrodes. The grouping of two orthogonal separation techniques, together with analytes preconcentration techniques, significantly enhanced resolution and sensitivity for 2-D separation of cationic compounds. The resulting electrophoregram was quite different from that of either single CZE or MEKC. Up to 14,000- to 35,000-fold improvement in sensitivity was obtained relative to conventional electrokinetic injection method. The limits of detection (S/N=3) were in the range of 0.03-0.1 microg/L. The number of theoretical plates was in the range of 103,000-184,000. This method was successfully applied to the analysis of trace cationic cardiovascular drugs in wastewater.

Heart-cut capillary electrophoresis for drug analysis in mouse blood with electrochemical detection.

A novel separation method, which interfaced capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC), was developed for analysis of weak basic compounds. CZE was used as the first separation, from which the effluent components were transferred and further analyzed by MEKC. As the key to successful integration of CZE and MEKC, a new microhole interface was designed. On-line concentration strategies, namely pH junction and sweeping, were employed to avoid sample zone diffusion at the interface. For evaluation of the feasibility and effectiveness of the capillary electrophoresis (CE) system, basic cardiovascular drugs were used as model compounds. The resulting electropherogram was quite different from that of either CZE or MEKC separation. The relative standard deviations (RSDs) of peak height, peak area, and migration time were in the ranges of 2.7% to 4.5%, 1.3% to 3.6%, and 0.8% to 1.4%, respectively, and detection limits (signal/noise=3) were 0.015 to 0.052 mg/L. The proposed method was successfully applied to the determination of basic cardiovascular drugs in mouse blood.

Sequential preconcentration by coupling of field amplified sample injection with pseudo isotachophoresis-acid stacking for analysis of alkaloids in capillary electrophoresis.

A novel on-column sequential preconcentration method based on the combination of field-amplified sample injection induced by acetonitrile and pseudo isotachophoresis (ITP)-acid stacking is developed for simply but efficiently concentrating alkaloid cations in a high-salt sample matrix in capillary electrophoresis. Acetonitrile (70%) added to a sample solution with a high-salt sample matrix not only induces field-amplified sample stacking by decreasing conductivity but also acts as a termination reagent in the succeeding pseudo ITP. After sample injection had been completed, a plug of H(+) was injected electrokinetically and a neutralization reaction between H(+) and tartrate from the buffer solution produced a low conductivity zone, in which the injected analyte cations were further concentrated. With the sequential preconcentration method, a 3 orders of magnitude detection sensitivity (1,400-fold) increase could be observed compared with the conventional electrokinetic injection method, without compromising separation efficiency and peak shape, and detection limits of 0.1 ng/mL for myosmine and 0.3 ng/mL for anabasine with the conditions selected were achieved. The calibration curves demonstrated good linearity in the concentration ranges 1.3-600 ng/mL for myosmine and 4.9-900 ng/mL for anabasine, respectively. The proposed method has been used to analyze successfully trace alkaloids in cigarette samples.

[Functions of spleen tyrosine kinase (Syk) gene and its correlation to neoplasms].

Spleen tyrosine kinase (Syk) was thought to be a hematopoietic cell-specific signaling molecule and plays an essential role in maturation of lymphocytes and activation of immune cells. Recent evidences show that it is also expressed by many non-hematopoietic cell types. Down-regulation of Syk expression was first observed during breast cancer progression, now its abnormal expression has also been detected in many other types of tumors. Syk could suppress tumorigenesis and metastasis, but the molecular mechanism remains unknown. Promoter hypermethylation is one of the mechanisms that lead to silencing of Syk gene. Increasing clinical evidences reveal a positive correlation of reduced Syk expression to increased risk for metastasis, and indicate that Syk may be a potential new tumor suppressor.

Synthesis of methane in nanotube channels by a flash.

Inorganic synthesis of organic molecules is a significant step for the primordial life. Generally, inorganic synthesis of methane necessitates, in addition to catalyst, a high-temperature and high-pressure environment. Here we will show that such an environment could be locally and instantly realized in the channels of single-walled carbon nanotubes (SWNTs) even under room temperature and ultrahigh vacuum conditions just by a visible-light flash, owing to the ultra-photothermal effect of nanomaterials. As a result, methane signals were definitely detected by using a quadrupole mass spectrometer and an optical fiber spectrometer. The mechanisms were interpreted as Fischer-Tropsch synthesis. Our results provide an alternative explanation of abiogenic methane origin.

Determination of aflatoxins in high-pigment content samples by matrix solid-phase dispersion and high-performance liquid chromatography.

A fast, efficient, and cost-effective method was developed for the analysis of aflatoxins in farm commodities with high-pigment content, such as chili powder, green bean, and black sesame. The proposed method involved matrix solid-phase dispersion (MSPD) and high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) with postcolumn electrochemical derivatization in a Kobra cell. The MSPD procedure combined the extraction with neutral alumina and pigment cleanup with graphitic carbon black (GCB) in a single step. The recoveries of aflatoxins ranged from 88% to 95% with the relative standard deviations (RSD) less than 6% (n = 6). The limits of detection (LODs) were 0.25 ng/g aflatoxin B1, G1, and 0.10 ng/g aflatoxin B2, G2, respectively. The analytical results obtained by MSPD were compared to those of the immunoaffinity column (IAC) cleanup method. No significant differences were found between the two methods by t-test at the 95% confidence level.

Visible-light-induced water-splitting in channels of carbon nanotubes.

The visible-light-induced split of water confined in channels of single-walled carbon nanotubes (SWNTs) was experimentally studied. Arc-discharging synthesized SWNTs were used to adsorb water vapor and then were irradiated in a vacuum by using light from a camera flash. It was found that a great amount of hydrogen-rich gases could be repeatedly produced under several rapid flashes of light, occasionally accompanying evident charge emission phenomena. A quantitative method was developed to estimate the relative amount of gas components on the basis of the data acquired with an ion gauge and a quadrupole mass spectrometer. The results indicated that hydrogen occupied about 80 mol % of the photogenerated gases, with other components such as carbon oxides, helium, methane and trace of ethane, and the total gas yield in one flash (0.1-0.2 J/cm2, 8 ms) reached 400-900 ppm of the mass of the SWNTs. Such a yield could be repeatedly obtained in serial flashings until the adsorbed water was depleted, and then, by sufficiently adsorbing water vapor again, the same phenomena could be reproduced.

On-line sequential preconcentration of inorganic anions by anion-selective exhaustive injection and base-stacking in capillary zone electrophoresis.

A sequential electrostacking method based on anion-selective exhaustive injection (ASEI) and base-stacking (BS) is presented for the preconcentration and determination of inorganic anions by capillary zone electrophoresis (CZE) in this paper. Tetradecyltrimethylammonium bromide as an electroosmotic flow (EOF) modifier was added into the buffer to suppress EOF of the capillary. Firstly, a water plug was hydrodynamically injected into the capillary. During ASEI under negative high voltage, the sample anions migrated quickly towards the boundary between the water plug and buffer in the capillary. Then an alkaline zone was injected electrokinetically to concentrate the anions further. With the sequential electrostacking method, the preconcentration factor of (0.8-1.3) x 10(5) was obtained compared with the conventionally electrokinetic injection and the relative standard deviation of peak area was 3.3-5.3% (n = 5). The detection limits of ASEI-BS-CZE for six inorganic anions were 6-14 ng/L. The proposed method has been adopted to analyze six anions in cigarette samples successfully.