Oxidation and corrosion behaviors of Mg-based nanoparticles

Various Mg-based nanoparticles were prepared by evaporating bulk magnesium in the atmospheres of Ar, Ar+N2 and CH4, respectively. The formations, phases, morphologies, thermal properties and corrosion behaviors of these kinds of nanocomposite particles were investigated by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), thermogravimetric-differential thermal analysis (TG/DTA) and potentiodynamic polarisation scan (PPS). It is shown that the Mg-based nanoparticles produced in Ar and Ar+N2 atmospheres have hexangular crystal habits with particles' sizes ranging from 50 to 400 nm, while the nanoparticles produced in CH4 atmosphere have amorphous carbon out layers with particles' sizes among 20-100 nm. TG/DTA results show that two-steps oxidation process can be confirmed for all samples, which may be attributed to the oxidations of out layer and core of nanoparticle. The CH4 atmosphere-prepared nanoparticles exhibit better corrosion resistance properties due to its peculiar carbon doping.

Low-temperature nitridation of Fe nanoparticles precursor

Nitridation of Fe nanoparticle precursor was performed in a NH3 atmosphere at the temperatures of 473 K and 673 K for one hour. Fe nanoparticles precursor had a typical spherical shape with iron oxides shell and alpha-Fe core, which was obtained by an arc-discharge method. Up to date, the nitriding temperature of 473 K in present work was the lowest by thermal ammonolysis method because of the characteristics of the nano-sized particles. The resultant product after nitridation was a mixture of iron-nitrides (gamma'-Fe4N and epsilon-Fe3N) nanoparticles with homogeneous dispersion. The nitriding mechanism, oxidizing behaviors and magnetic properties of iron-nitride nanoparticles were measured and discussed.

HIV/AIDS education effects on behaviour among senior high school students in a medium-sized city in China

Few studies have examined the long-term effects of peer-led HIV prevention in Chinese adolescents. A two-year follow-up study was conducted among senior high school students in a medium-sized city of Fujian Province, from 1 March 2006 to 30 April 2008. In all, 3068 students from 14 schools were invited in March 2006, and 893 students in five schools were followed up. Data were collected at baseline, right after intervention (one month later) and two years later by a self-administered questionnaire. In the intervention group, the average knowledge score including reproductive health and HIV/AIDS/sexually transmitted diseases rose from 4.30 to 7.06 one month later (P < 0.01) and to 7.08 two years later (P < 0.01). There was no significant difference between the average knowledge score after one month and two years (P > 0.05). Sustained increases were found in the attitude scores towards people living with HIV/AIDS (PLWH) and intention of condom use after intervention. The study indicates that peer-led HIV prevention education succeeds in improving and sustaining HIV/AIDS-related knowledge and some behaviour intentions. Future research should focus on strategies to sustain long-term behaviour change.

Normal range values for thromboelastography in healthy adult volunteers

Thromboelastography (TEG) provides a functional evaluation of coagulation. It has characteristics of an ideal coagulation test for trauma, but is not frequently used, partially due to lack of both standardized techniques and normal values. We determined normal values for our population, compared them to those of the manufacturer and evaluated the effect of gender, age, blood type, and ethnicity. The technique was standardized using citrated blood, kaolin and was performed on a Haemoscope 5000 device. Volunteers were interviewed and excluded if pregnant, on anticoagulants or having a bleeding disorder. The TEG parameters analyzed were R, K, alpha, MA, LY30, and coagulation index. All volunteers outside the manufacturer's normal range underwent extensive coagulation investigations. Reference ranges for 95% for 118 healthy volunteers were R: 3.8-9.8 min, K: 0.7-3.4 min, alpha: 47.8-77.7 degrees, MA: 49.7-72.7 mm, LY30: -2.3-5.77%, coagulation index: -5.1-3.6. Most values were significantly different from those of the manufacturer, which would have diagnosed coagulopathy in 10 volunteers, for whom additional investigation revealed no disease (81% specificity). Healthy women were significantly more hypercoagulable than men. Aging was not associated with hypercoagulability and East Asian ethnicity was not with hypocoagulability. In our population, the manufacturer's normal values for citrated blood-kaolin had a specificity of 81% and would incorrectly identify 8.5% of the healthy volunteers as coagulopathic. This study supports the manufacturer's recommendation that each institution should determine its own normal values before adopting TEG, a procedure which may be impractical. Consideration should be given to a multi-institutional study to establish wide standard values for TEG.

Management of the Antenatal Preterm Fetal Lung in the Prevention of Respiratory Distress Syndrome in Lambs

We have explored change in pulmonary compliance before, and after, repeated deep insufflation of the lungs to a pressure of 35 cm H2O, in 130-days gestation fetal lambs delivered by cesarean section, and while still connected to the intact umbilical cord and the ewe. As a group, all 15 out of 28 fetal lambs that had a rise in total compliance to above 0.2 ml (cm H2O)-1 kg-1 after the first inflation, tolerated 24 h of mechanical ventilation with excellent health and good lung function; only 3 animals out of 13 that showed no similar initial rise in compliance after the first inflation, ultimately survived. We believe the first deep insufflation is an important therapeutic intervention and a useful index to rapidly assess chance of survival in a high-risk fetal lamb population.

Subpopulations of stem-like cells in side population cells from the human bladder transitional cell cancer cell line T24

Cancer stem cells can be isolated from human tumours using specific cell surface markers. Bladder cancer cells, however, lack specific cell surface markers, making this approach impracticable. In this study an alternative method was used, involving isolation of side population cells to explore the stem cell characteristics of bladder cancer. Side population cells were isolated from the bladder transitional cell cancer cell line T24 and examined for potential stem cell characteristics related to proliferation, cell cycle distribution, self-renewal and differentiation. It was observed that T24 side population cells have stronger proliferative and colony formation abilities than non-side population cells. Side population cells were also more resistant to chemotherapy and radiotherapy, which may be due to expression of the ATP-binding cassette half-transporter, sub-family G, member 2 protein. Overall, the results suggest that side population cells from the human bladder transitional cell cancer cell line T24 harbour stem-like cells.

Autoimmune pancreatitis results from loss of TGFbeta signalling in S100A4-positive dendritic cells

BACKGROUND AND AIMS

Autoimmune pancreatitis (AIP) is a poorly understood human disease affecting the exocrine pancreas. The goal of the present study was to elucidate the pathogenic mechanisms underlying pancreatic autoimmunity in a murine disease model.

METHODS

A transgenic mouse with an S100A4/fibroblast-specific protein 1 (FSP1) Cre-mediated conditional knockout of the transforming growth factor beta (TGFbeta) type II receptor, termed Tgfbr2(fspKO), was used to determine the direct role of TGFbeta in S100A4(+) cells. Immunohistochemical studies suggested that Tgfbr2(fspKO) mice develop mouse AIP (mAIP) characterised by interlobular ductal inflammatory infiltrates and pancreatic autoantibody production. Fluorescence-activated cell sorting (FACS)-isolated dendritic cells (DCs) from diseased pancreata were verified to have S100A4-Cre-mediated DNA recombination.

RESULTS

The Tgfbr2(fspKO) mice spontaneously developed mAIP by 6 weeks of age. DCs were confirmed to express S100A4, a previously reported protein expressed by fibroblasts. Adoptive transfer of bone marrow-derived DCs from Tgfbr2(fspKO) mice into 2-week-old syngenic wild-type C57BL/6 mice resulted in reproduction of pancreatitis within 6 weeks. Similar adoptive transfer of wild-type DCs had no effect on pancreas pathology of the host mice. The inability to induce pancreatitis by adoptive transfer of Tgfbr2(fspKO) DCs in adult mice suggested a developmental event in mAIP pathogenesis. Tgfbr2(fspKO) DCs undergo elevated maturation in response to antigen and increased activation of naïve CD4-positive T cells.

CONCLUSION

The development of mAIP in the Tgfbr2(fspKO) mouse model illustrates the role of TGFbeta in maintaining myeloid DC immune tolerance. The loss of immune tolerance in myeloid S100A4(+) DCs can mediate mAIP and may explain some aspects of AIP disease pathogenesis.

HIV/AIDS-related knowledge, sources and perceived need among senior high school students: a cross-sectional study in China

This study aimed to assess HIV/AIDS-related knowledge, sources and perceived need among senior high school students in China. A total of 2668 senior high school students aged 15.17–23.42 years participated in the survey. A self-administered questionnaire was used to collect information on HIV/sexually transmitted infection-related knowledge, sources and perceived information need. The results showed that levels of HIV/AIDS knowledge were distributed as follows: low for 6.8%, moderate for 29.6% and high for 63.7%. The most important information sources were, in rank order, TV/photographic recording (72.1%), school heath education curriculum (51.8%) and reading materials (45.7%). About half of the students, 46.3%, confirmed a need for more information and 87.8% of the sampled senior high school students communicated with others if he/she had problems related to HIV/AIDS. Strengthening and improving information sources, particularly its accuracy and comprehensiveness, would help in ensuring that adolescents obtained the HIV/AIDS health information they needed.

Kidney transplantation from hepatitis B surface antigen positive donors into hepatitis B surface antibody positive recipients: a prospective nonrandomized controlled study from a single center

The number of patients on renal transplant waiting list is increasing rapidly in many countries, exacerbating the shortage of organs. We conducted a study to evaluate the safety and efficacy of deceased-donor kidney transplantation from hepatitis B surface antigen (HBsAg)-positive (+) donors into hepatitis B surface antibody (anti-HBs)-positive (+) recipients. Sixty-five patients received grafts from HBsAg(+) donors, and 308 subjects received grafts from HBsAg-negative(-) donors. Posttransplantation, recipients with HBsAg(-) grafts or HBsAg(+) grafts received 400 U of hepatitis B immunoglobulin once and twice, respectively. The seven recipients who received grafts from hepatitis B virus (HBV) DNA(+) donors were treated with hepatitis B immunoglobulin 400 U weekly for 3 months and lamivudine 100 mg daily for 6 months. All patients were monitored for liver function and hepatitis B viral status. The follow-up period was 38.7 +/- 15.4 months. Although two recipients developed de novo HBV infection, neither patient developed severe liver dysfunction nor died. The incidence of liver injury (39/65 vs. 207/308, chi-square test, p > 0.05) and survival (log-rank test, p > 0.05) did not differ between the groups. We conclude that anti-HBs(+) recipients receiving HBsAg(+) grafts did as well as those receiving HBsAg(-) grafts.

Distinct ribotypes and rates of antimicrobial drug resistance in Clostridium difficile from Shanghai and Stockholm

Seventy-five clinical isolates of Clostridium difficile from Shanghai and 80 from Stockholm were investigated. The prevalence of toxin A-negative, toxin B-positive isolates of C. difficile among isolates from Shanghai (33.3%) was significantly higher than among isolates from Stockholm (0%). Both sets of isolates were fully susceptible to metronidazole and vancomycin. However, the MICs of fluoroquinolones, erythromycin-clindamycin, tetracycline, rifampin and fusidic acid were significantly higher for the Shanghai isolates than for the Stockholm isolates. Thirty-three PCR ribotypes were identified; a dominant clone, 017, accounted for 18.7% of Shanghai isolates, whereas clone 005 dominated among Stockholm isolates, accounting for 11.3%. Strains 027 and 078 were not detected. No outbreak occurred during the study period.

Susceptibility-weighted imaging in the diagnosis of early basal ganglia germinoma

BACKGROUND AND PURPOSE

Germinomas originating from the basal ganglia (BG) are rare. Early diagnosis is important for favorable prognosis, but it is difficult due to the slow clinical course and subtle changes on neuroimaging. The purpose of this study was to evaluate the usefulness of susceptibility-weighted imaging (SWI) in the diagnosis of early BG germinoma.

MATERIALS AND METHODS

From 2006 to 2008, 6 BG germinomas were diagnosed in children at our institution by pathology. Conventional MR imaging and SWI were available in all cases. Clinical, neuroradiologic, and follow-up features were retrospectively studied.

RESULTS

Three cases were classified as early BG germinomas. Conventional MR imaging demonstrated that the tumor size was <10 mm in the largest diameter. The tumors were invisible or showed slight hyperintensity on T1-weighted images (T1WI) and patchy slight hyperintensity on T2-weighted images (T2WI) without mass effect or enhancement. On SWI, the tumors appeared as obvious hypointensity in the globus pallidus and putamen, and the size was larger than that on conventional T1WI and T2WI. The other 3 cases with tumor size >10 mm in largest diameter were classified as late BG germinomas, with tumor necrosis, fluid-fluid levels, and perifocal edema, including 1 case with subependymal spread. On SWI, only the solid portion of the tumors showed hypointensity. No recurrence was noted on follow-up.

CONCLUSIONS

SWI appears to be more sensitive in detecting early BG germinomas than conventional MR imaging. This capability may prove to be useful in future attempts to characterize early BG germinomas.