[Determination of tributyl phosphate in the air of workplace by gas chromatography]

Objective: To establish a practical method forsampling and detectingtributyl phosphate intheworkplace. Methods: The samples were extracted by glass fiber membrane, eluted with ether, separated by gas chromatography, and detected by flame photometric detector. Results: There were good linear relationship in the minimum detection concentration was 7.2-720.0 μg/ml, and the correlation coefficient was 0.999 92. The detection limit was 0.86 μg/ml, and the minimum detection concentration was 0.14 mg/m(3) (sample volume was 30 L) . Recovery rates were 99.8%-100.2%. The with-in relative standard deviations were 4.0%-5.4% and the between relative standard deviations were 2.0%-5.5%, and average samplingefficiency was about 99.1%-100.0%. Conclusion: This method conforms with the requirements of "Standardization of Methods for Determination of Toxic Substance in Workplace" . Tributyl phosphate in air could be determined accurately using this method.

[Determination of diethyl phthalate in the air of workplace by gas chromatography]

Objective: To establish a method for the determination of diethyl phthalate by gas chromatography in the air of workplaces. Methods: Diethyl phthalate in the air of workplace was collected throμgh glass fiber filter, eluted with methylbenzene, and detected by gas chromatography coupled with FID detectors. Results: The linear range of diethyl phthalate determined by this method was 14.0~1 400 μg/ml, y=2.09801x-3.66229, and the coefficient correlation was 0.999 99. The detection limit was 1.10 μg/ml, and the minimum detection concentration was 0.18mg/m(3) (collected sample volume was 30 L) . The within-run precisions were 1.04%~2.75%, and the between-run precisions were 0.34%~1.30%. The recovery rates were 98.72%~103.21%, and sampling efficiency was 97.2%~100.0%. The elution efficiencies were 97.25%~98.68%. The samples could be stored at room temperature for 15 days. Conclusion: The indicators established in this study were conformed with the requirements of GBZ/T210.4-2008, "The Guidelines for the Development of Occupational Hygiene Standards Methods Part 4: Determination of Chemical Substances in the Air of Workplaces" . Diethyl phthalate in the workplace air could be rapidly collected, accurate separated and determinated. This method is applicable to the determination of diethyl phthalate in the workplace air.

[Expression level and clinical significance of LncRNA HOXA11-AS in esophageal squamous cell carcinoma patients]

Objective: To explore the expression of long noncoding RNA (lncRNA) HOXA11-AS in esophageal squamous cell carcinoma tissues and the relationship of HOXA11-AS level with clinical outcomes. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the expression level of HOXA11-AS in cell lines HET-1A, EC9706, EC109, and in tumor tissue and paired adjacent tissue samples from 73 ESCC patients who received surgical resection.The correlations of the expression level of HOXA11-AS with clinicopathological features and prognosis were also analyzed. Results: The relative expression levels of HOXA11-AS in tumor tissue and paired adjacent tissue were 0.832±0.387 and 2.486±1.087, respectively, with significant difference (P<0.001). The expression of HOXA11-AS was upregulated in 63.0%(46/73)ESCC tissues. The relative expression levels of HOXA11-AS in HET-1A, EC-9706 and EC-109 cells were 1.000, 23.553±3.221 and 17.217±1.968, respectively. The expression level of HOXA11-AS was upregulated in ESCC cell lines (P<0.001). High expression level of HOXA11-AS was correlated with histological grade and lymph node metastasis of ESCC patients (P<0.05). However, it was not associated with the age, gender, depth of infiltration and TNM staging (P>0.05). The median overall survival (OS) and median disease-free survival (DFS) of patients with low HOXA11-AS expression were 43 months and 42 months, respectively, significantly longer than 37 months and 28 months of patients with HOXA11-AS high expression (P<0.05). Cox model multivariate analysis showed that the expression of HOXA11-AS and lymph node metastasis were independent factors of poor prognosis of ESCC patients. Conclusions: The expression of HOXA11-AS is upregulated in esophageal cancer cell lines and tissues. High expression of HOXA11-AS is associated with poor prognosis of ESCC patients.Therefore, LncRNA HOXA11-AS may serve as a predictive marker of postoperative ESCC patients.

Measurement of Ti-6Al-4V alloy ignition temperature by reflectivity detection

Fires resulting from titanium combustion are complex and violent processes which can instantly burn a titanium alloy once ignited. The occurrence of titanium combustion is a disaster for aircraft. Accurate measurement of the ignition temperature of titanium alloys is of significance in preventing such fires and in investigating combustion-resistance properties. In this study, monochromatic temperature and emissivity measurement methods based on reflectivity detection were used to determine the ignition temperature of a titanium alloy. Experiments were carried out using a titanium burning apparatus. The temperatures of titanium in the oxidation stage before ignition and in the combustion stage during the ignition process were measured using wavelengths of 1050 nm and 940 nm, respectively. Experimental results showed that the ignition temperature of the titanium alloy could be measured by reflectivity detection and that measurement precision during thermal oxidation (500-900 °C) was ±1 °C. The temperature of the ignition process ranged between 1653 and 1857 °C, and the ignition temperature was around 1680 °C.

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

[A clinical analysis of 123 cases of primary empty sella]

Objective: This study was conducted to analyze the clinical characteristics and pituitary function of patients with primary empty sella (PES). Methods: The clinical data from 123 hospitalized adult patients with PES from January 2010 to May 2016 were retrospectively studied. Results: (1) The average age of the 123 (male 43, female 80) PES patients was (59.2±13.6) years (ranging 24-92 years), among whom 61% patients were in the age group between 50-69 years. (2) The symptoms of the patients included fatigue (56.1%), headache (34.1%), nausea and vomiting (17.9%), gonadal dysfunction (17.1%), visual disturbance (5.7%) and hypopituitarism crisis (3.3%). (3) Hypopituitarism was found in 66 of the 123 patients. Among them, 36.6%, 31.7% and 17.1% were central hypoadrenalism, hypogonadism, and hypothyroidism, respectively.The percentage of hypopituitarism in complete PES was significantly higher than that in partial PES (P<0.05). (4) Sixteen patients were concomitant with other autoimmune diseases including 11 patients with Graves' disease and 2 with Cushing's syndrome due to adrenal adenoma. Conclusions: The incidence of hypopituitarism in PES was 53.7%, in which the pituitary-adrenal axis hypofunction was more common. An overall evaluation of the pituitary function was essential for the patients who had headache and fatigue, or with suspected PES. The patients with hypopituitarism should be given hormone replacement therapy in time and followed up afterword.

Molecular mechanisms of apoptosis in hepatocellular carcinoma cells induced by ethanol extracts of Solanum lyratum Thumb through the mitochondrial pathway

AIM

To explore the induction effects and mechanism of Solanum lyratum Thumb (ST) on human hepatocellular carcinoma SMMC-7721 cells through the mitochondrial pathway.

METHODS

The experiments were conducted on three groups: an experimental group (with ST ethanol extracts' concentration being 2.5, 5 and 10 mg/L), a negative control group (with only nutrient solution, 0 mg/L ST ethanol extracts), and a positive control group (2.5 mg/L DDP). The inhibition rate of cell proliferation was checked by using the methyl thiazolyl tetrazolium method, and cell apoptosis was tested by TUNEL method. Furthermore, RT-PCR was used to examine mRNA expression of Fas, FasL, caspase-8, caspase-3, p53 and Bcl-2 genes.

RESULTS

Compared with the negative control group, the inhibition and apoptosis rates of the experimental group with different concentrations of ST extracts on human hepatocellular carcinoma SMMC-7721 cells significantly increased (P < 0.05). Besides, the mRNA expression of FasL and Bcl-2 significantly decreased (P < 0.05) while the mRNA expression of Fas, caspase-8, caspase-3 and p53 increased significantly. When compared with the positive control group, the experimental groups with 5 mg/L ST ethanol extracts showed effects similar to the positive control group.

CONCLUSION

ST ethanol extracts induced the apoptosis of hepatocellular carcinoma SMMC-7721 cells through up-regulated Fas, caspase-8, caspse-3 and p53, and down-regulated FasL and Bcl-2 in the mitochondrial pathway.

Gene polymorphisms of pathogenic Helicobacter pylori in patients with different types of gastrointestinal diseases

Helicobacter pylori (H. pylori) is a kind of chronic infectious pathogen which can cause chronic gastritis, peptic ulcer, gastric cancer and other diseases. The genetic structure of the pathogenic genes of H. pylori varies largely, which contributes to the differences in virulence among various strains, and in clinical symptoms. Virulence genes of H. pylori can be categorized into three main classes: those related to adhesion and colonization, those related to gastric mucosal injury, and others. This review focuses on the relationship between genetic polymorphisms of the three classes of virulence genes of H. pylori and diseases. Most of the genetic polymorphisms of the main virulence factors of H. pylori are summarized in this paper.

[The effect of occupational exposure to coal tar pitch workers' health]

Objective: To investigate the effect of occupational exposure to coal tar pitch on workers' health and metabolism. Methods: 805 workers exposed to coal tar pitch were selected as exposure group from the produce and em-ploy factory. Other people handle administrative and logistical affairs who not exposed to coal tar pitch were selected as control group. Fix-point sample of air were collected to detect the concentration of coal tar pitch. Do physical examination and questionnaire to collect workers' basic and healthy information. To detect the metabolic product of urine samples in laboratory. Results: Anomaly detection rate of the skin in exposure group is 10.61. The lung function indices (FEV_1.0%) in exposure group were significantly lower than control group (P<0.05) . The monocyte count and monocyte rate in expo-sure group were significantly higher than control group (P<0.05) . The metabolic product content of PAHS in urine sam-ples is significantly higher in exposed group than control group (P<0.05) . Conclusion: The metabolic product content of polycyclic aromatic hydrocarbon is higher in exposed workers. Coal tar pitch damage workers' skin and lung function. It can cause pruritus chromatodermatosis and so on.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

Absolute group refractive index measurement of air by dispersive interferometry using frequency comb

The absolute group refractive index of air at 1563 nm is measured by dispersive interferometry, and a combined uncertainty of 1.2 × 10(-8) is achieved. The group refractive index of air is calculated from the dispersive interferograms of the two beams passing through the inner and outer regions of a vacuum cell by fast-Fourier-transform. Experimental results show that the discrepancies between our method and modified Edlén equation are less than 3.43 × 10(-8) and 4.4 × 10(-8) for short-term and long-term experiments, respectively. The interferogram update rate is 15 ms, which makes it suitable for application of real-time monitoring. Furthermore, it is promising to improve the measurement uncertainty to 3.0 × 10(-9) by changing the material of the vacuum cell and measuring its length more accurately through optical interferometry.

Clinical significance of serum procalcitonin level monitoring on early diagnosis of severe pneumonia on children

OBJECTIVE

To discuss the method for early diagnosis of severe pneumonia on children.

PATIENTS AND METHODS

Fifty-six children with severe pneumonia were enrolled from Department of Pediatrics and Intensive Care Unit (ICU) of our hospital and divided into two groups according to parasitological detection: bacterial pneumonia group consisting of 34 children patients and non-bacterial pneumonia group of 32 children patients. In the meanwhile, 37 healthy children, who were confirmed without infection through physical examination, were also enrolled and grouped in into normal control group. Peripheral venous blood of all children was collected to detect their procalcitonin (PCT).

RESULTS

PCT level of patients in bacterial pneumonia group was significantly higher than that in the non-bacterial pneumonia group and control group, and difference had statistical significance (p < 0.01); serum PCT level on patients in bacterial pneumonia group before and after treatment had statistical significance (p < 0.01); serum PCT level on patients in non-bacterial pneumonia group before and after treatment had no statistical significance (p > 0.05).

CONCLUSIONS

PCT was a very important biomarker for the diagnosis of bacterial infection and also a sensitive indicator for the distinction of child bacterial pneumonia and non-bacterial pneumonia. It had significant clinical diagnosis and differential diagnosis value.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Synthesis and biological evaluation of 6-substituted indolizinoquinolinediones as catalytic DNA topoisomerase I inhibitors

In our previous work, indolizinoquinolinedione derivative 1 was identified as a Top1 catalytic inhibitor. Herein, a series of 6-substituted indolizinoquinolinedione derivatives were synthesized through modification of the parent compound 1. Top1 cleavage and relaxation assays indicate that none of these novel compounds act as classical Top1 poison, and that the compounds with alkylamino terminus at C-6 side chain, including 8, 11-16, 18-21, 25, 26 and 28-30, are the most potent Top1 catalytic inhibitors. Top1-mediated unwinding assay demonstrated that 14, 22 and 26 were Top1 catalytic inhibitors without Top1-mediated unwinding effect. Moreover, MTT results showed that compounds 26, 28-30 exhibit significant cytotoxicity against human leukemia HL-60 cells, and that compound 26 exerts potent cytotoxicity against A549 lung cancer cells at nanomolar range.

Inhibitory effects of emodin, baicalin, schizandrin and berberine on hefA gene: treatment of Helicobacter pylori-induced multidrug resistance

AIM

To investigate the inhibitory effects of emodin, baicalin, etc. on the hefA gene of multidrug resistance (MDR) in Helicobacter pylori (H. pylori).

METHODS

The double dilution method was used to screen MDR H. pylori strains and determine the minimum inhibitory concentrations (MICs) of emodin, baicalin, schizandrin, berberine, clarithromycin, metronidazole, tetracycline, amoxicillin and levofloxacin against H. pylori strains. After the screened MDR stains were treated with emodin, baicalin, schizandrin or berberine at a 1/2 MIC concentration for 48 h, changes in MICs of amoxicillin, tetracycline, levofloxacin, metronidazole and clarithromycin were determined. MDR strains with reduced MICs of amoxicillin were selected to detect the hefA mRNA expression by real-time quantitative PCR.

RESULTS

A total of four MDR H. pylori strains were screened. Treatment with emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some strains, decreased by 1 to 2 times, but did not significantly change the MICs of clarithromycin, levofloxacin, and metronidazole against MDR strains. In the majority of strains with reduced MICs of amoxicillin, hefA mRNA expression was decreased; one-way ANOVA (SPSS 12.0) used for comparative analysis, P < 0.05.

CONCLUSION

Emodin, baicalin, schizandrin and berberine significantly decreased the MICs of amoxicillin and tetracycline against some H. pylori strains, possibly by mechanisms associated with decreasing hefA mRNA expression.

Osteonecrosis of the femoral head: using CT, MRI and gross specimen to characterize the location, shape and size of the lesion

OBJECTIVE

To investigate the accuracy of using CT and MRI to characterize lesions of osteonecrosis of the femoral head (ONFH).

METHODS

Coronal CT and MRI scans were performed on 30 femoral head specimens collected from 23 patients who had undertaken hip arthroplasty owing to ONFH. The results were compared with findings from coronal sectional gross specimens. Two radiologists independently measured the volume of necrotic lesions from CT and MR images using computer software, and the results were averaged. The volume of specimens' necrotic lesion was measured using the water displacement method.

RESULTS

There was a high degree of consistency between CT, MRI and the coronal sectional gross specimen on the location, shape and spatial structure of lesions. Differences of the lesion volume measured from CT and MR images were not statistically significant between two radiologists. The necrotic lesion volumes measured from CT and MR images and gross specimens were 22.07 ±5.35, 22.21 ± 5.15 and 21.12 ±4.96 cm(3), respectively, and the differences were not statistically significant (F = 0.396; p = 0.674).

CONCLUSION

For patients with ONFH in Association Research Circulation Osseous stage III or above, CT and MRI can accurately display the characterization of lesion.

ADVANCES IN KNOWLEDGE

The size and location of necrotic lesions are major factors associated with femoral head collapse. CT is superior to MRI in identifying subchondral fracture. CT can help diagnose and predict the prognosis of ONFH.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Effect of berberine and other herbal extracts on gyrA gene mutations in multidrug resistant Escherichia coli

AIM: To investigate if berberine and other herbal extracts have an effect on gyrA gene mutations in multidrug resistant Escherichiae coli (E. coli).

METHODS: The multidrug resistance of E. coli to ofloxacin, ciprofloxacin and norfloxacin was determined by K-B method. Multidrug resistant E. coli was cultured in the presence of berberine or other herbal extracts and passaged once every 2 d for a total of 15 times. E. coli DNA was extracted to amplify the gyrA gene by PCR, and gyrA gene sequence was analyzed to check the mutation status before and after treatment.

RESULTS: The multidrug resistant E. coli had gyrA gene mutations, mainly C-T mutation at nt83 and G-A mutation at nt87. After treatment with berberine or other herbal extracts for 30 d, no significant changes were found in the gyrA gene mutations.

CONCLUSION: Multidrug resistant E. coli to quinolones carry gyrA gene mutations, and berberine and other herbal extracts have no significant impact on these mutations.

Tamoxifen reduces infiltration of inflammatory cells, apoptosis and inhibits IKK/NF-kB pathway after spinal cord injury in rats

In this study, neuroprotective effect of tamoxifen has been explored in spinal cord injury (SCI) in rats by examining factors influencing IKK/NF-kB pathway in SCI in rats. It has been shown in several studies that IKK/NF-kB signaling pathway plays a key role in pathophysiology of SCI. In this study, three groups of rats (n = 17 each) were selected that included, tamoxifen group (here tamoxifen was injected after SCI in rats), SCI group (here only dimethylsulfoxide was administered after inducing SCI in rats) and sham group (here only laminectomy was performed). The effect of tamoxifen (5 mg/kg) on various factors responsible for activation of IKK/NF-kB signaling pathway including NF-kB p65, phosphorylated I-kBα was studied through Western blotting as well as densitometry. The examination of expression of active caspase-3 and myeloperoxidase activity was also carried out through Western blot analysis and densitometry. A comparison of three groups of rats showed that administration of tamoxifen significantly reduced the expression of NF-kB p65 and phosphorylated I-kBα (P < 0.05) compared to control. It also attenuated the expression of active caspase-3 resulting in the reduction of apoptosis, and infiltration of leukocytes to the injury site was also greatly reduced in the group where tamoxifen was administered. Statistical analysis through SPSS 13.0 software showed a significant decrease in the expression of inflammatory factors in groups where tamoxifen was administered. We conclude that tamoxifen possesses the potential neuroprotective effects that can be explored further for future therapeutic techniques in treating spinal cord injuries.

Helicobacter pylori isolates from ethnic minority patients in Guangxi: Resistance rates, mechanisms, and genotype

AIM: To investigate the rate of Helicobacter pylori (H. pylori) resistance to clarithromycin among ethnic minority patients in Guangxi, explore the underlying mechanisms, and analyze factors influencing genotype distribution of H. pylori isolates.

METHODS: H. pylori strains were isolated, cultured and subjected to drug sensitivity testing. The 23S rRNA gene of H. pylori isolates was amplified by PCR and analyzed by PCR-RFLP and direct sequencing to detect point mutations. REP-PCR was used for genotyping of H. pylori isolates, and NTsys_2 software was used for clustering analysis based on REP-PCR DNA fingerprints. Factors potentially influencing genotype distribution of H. pylori isolates were analyzed.

RESULTS: The rate of clarithromycin resistance was 31.3%. A2143G and A2144G mutations were detected in the 23S rRNA gene of all clarithromycin-resistant H. pylori isolates. At a genetic distance of 78%, clarithromycin-resistant H. pylori isolates could be divided into six groups. Significant clustering was noted among H. pylori isolates from patients with peptic ulcer or gastritis.

CONCLUSION: The rate of clarithromycin resistance is relatively high in ethnic minority patients in Guangxi. Main mechanisms of clarithromycin resistance are A2143G and A2144G mutations in the 23S rRNA gene. Clarithromycin-resistant H. pylori isolates can be divided into six groups based on REP-PCR DNA fingerprints. Several factors such as disease type may influence the genotype distribution of H. pylori isolates.

Effects of emodin and other herbal extracts on resistance of Helicobacter pylori to clarithromycin

AIM: To evaluate the effects of emodin and other herbal extracts on resistance of Helicobacter pylori (H. pylori) to clarithromycin, and to explore the methods for effectively inhibiting H. pylori antibiotic resistance.

METHODS: The MIC of herbal extracts against clarithromycin resistance of H. pylori was detected by double dilution method. Clarithromycin resistant H. pylori was cultured in medium containing herbal extracts at a concentration of half MIC and passaged once every 5 d for 6 times. The MIC of clarithromycin against antibiotic resistance of H. pylori was assessed before and after stress culture. The DNA of H. pylori was extracted to detect drug resistant-related gene mutations.

RESULTS: The MIC of clarithromycin against H. pylori was reduced by herbal extracts. The gene mutations of 23s rRNA A2143G and A2144G were detected in clarithromycin-resistant H. pylori. No back mutations were discovered after treatment with herbal extracts for 30 d.

CONCLUSION: Herbal extracts have a synergistic effect in inhibiting the clarithromycin resistance of H. pylori. The synergistic action is not associated with the back mutations of 23s rRNA gene mutations related to clarithromycin resistance of H. pylori.

Reducing computational costs in large scale 3D EIT by using a sparse Jacobian matrix with block-wise CGLS reconstruction

Electrical impedance tomography (EIT) is a fast and cost-effective technique to provide a tomographic conductivity image of a subject from boundary current-voltage data. This paper proposes a time and memory efficient method for solving a large scale 3D EIT inverse problem using a parallel conjugate gradient (CG) algorithm. The 3D EIT system with a large number of measurement data can produce a large size of Jacobian matrix; this could cause difficulties in computer storage and the inversion process. One of challenges in 3D EIT is to decrease the reconstruction time and memory usage, at the same time retaining the image quality. Firstly, a sparse matrix reduction technique is proposed using thresholding to set very small values of the Jacobian matrix to zero. By adjusting the Jacobian matrix into a sparse format, the element with zeros would be eliminated, which results in a saving of memory requirement. Secondly, a block-wise CG method for parallel reconstruction has been developed. The proposed method has been tested using simulated data as well as experimental test samples. Sparse Jacobian with a block-wise CG enables the large scale EIT problem to be solved efficiently. Image quality measures are presented to quantify the effect of sparse matrix reduction in reconstruction results.