Mechanisms for <100> interstitial dislocation loops to diffuse in BCC iron.

The mobility of dislocation loops in materials is a principle factor in understanding the mechanical strength, and the evolution of microstructures due to deformation and radiation. In body-centered cubic (BCC) iron, the common belief is that <100> interstitial dislocation loops are immobile once formed. However, using self-adaptive accelerated molecular dynamics (SSAMD), a new diffusion mechanism has been discovered for <100> interstitial dislocation loops. The key aspect of the mechanism is the changing of the habit planes between the {100} plane and the {110} plane, which provides a path for the <100> loops to diffuse one-dimensionally. The migration behavior modeled with SSAMD is further confirmed by in-situ transmission electron microscopy (TEM) measurements, and represents a significant step for understanding the formation of <100> loop walls and the mechanical behavior of BCC Fe under irradiation.

Comparison of flucytosine and fluconazole combined with amphotericin B for the treatment of HIV-associated cryptococcal meningitis: a systematic review and meta-analysis.

Treatment guidelines recommend combination antifungal therapy with amphotericin B (AmB) as an induction therapy for cryptococcal meningitis. The objective of this study was to compare the survival benefit between 5-FC (flucytosine) and fluconazole as second-line drugs given in combination with AmB. We carried out a systematic review and meta-analysis of prospective controlled studies reporting early combination treatment for human immunodeficiency virus (HIV)-associated cryptococcal meningitis. We searched MEDLINE, EMBASE and the Cochrane Library up to October 2013. Randomised trials and prospective cohort studies were selected. The primary outcome was mortality in the first 14 and 70 days. The secondary outcome was early fungicidal activity (EFA) in the first 2 weeks. Four trials were included in our study. All included studies could be considered to be of fair quality in their methodology. The meta-analysis suggested that mortality was lower in patients who were given AmB and 5-FC at the 2 weeks point (Fig. 2); the overall reduction in mortality with the 5-FC combination group was 44% [risk ratio (RR) 0.56, 95% confidence interval (CI) 0.33-0.95, p = 0.03]. EFA was significantly shorter in patients receiving AmB plus 5-FC [mean difference (MD) -0.10 log10 colony-forming units (CFU) per day, 95 % CI -0.11-0.09, p < 0.00001]. Mortality was no different between the 5-FC and fluconazole groups at the 3 months time point (p = 0.15) (Fig. 4). Adverse events occurred with similar frequency between the two treatment groups. There was no statistically significant difference in the survival rate between AmB in combination with high-dose fluconazole and the current standard of AmB plus 5-FC therapy for HIV-associated cryptococcal meningitis.

Giant cell tumour of the posterior cranial fossa: a case report.

Giant cell tumours (GCTs) of the cranium preferentially affect the sphenoid and temporal bones. We report a 19-year-old patient with GCT involving the left occipital bone and petromastoid portion of the temporal bone. CT and MRI revealed a predominantly expansive soft-tissue mass of the posterior cranial fossa. The patient underwent surgery. Permanent histopathological sections and immunostatins revealed the presence of a GCT. The radiological features and method of surgical intervention of this rare lesion are discussed.

Evaluation of mollusks as biomonitors to investigate heavy metal contaminations along the Chinese Bohai Sea.

Two gastropod species (Rapana venosa and Neverita didyma) and three bivalve species (Mytilus edulis, Crassostrea talienwhanensis and Ruditapes philippinarum) were collected from eight sites along the coastline of the Chinese Bohai Sea for the investigation of heavy metal contaminations. Cd, Co, Cu, Ni, Pb and Zn were analyzed by using pressure nebulization-inductively coupled plasma-mass spectrometer. Two certified reference materials Dogfish mussel (DORM-2) and Mussel (GBW 08571) were used to validate the methods and the obtained results proved to be in good agreement with the certified values. The results of the present study showed that Crassostrea talienwhanensis possessed a much greater ability for bioaccumulation of Cu and Zn than did the other species. Rapana venosa manifested the most bioaccumulation capacity of Cd. Among the five species, the Ruditapes philippinarum possessed the highest content of Ni. Furthermore, Cd, Cu and Zn contents in some gastropods and oysters samples exceeded the maximum permissible levels established by WHO. Due to their special bioaccumulation capacity of Cd and Ni, Rapana venosa and Ruditapes philippinarum had the potential of being used as biomonitors to control the aquatic contaminations of heavy metals.

Application of solid-phase microextraction for the determination of organophosphorous pesticides in aqueous samples by gas chromatography with flame photometric detector.

A method based on solid-phase microextraction and gas chromatography flame photometric detector for the determination of organophosphorous pesticides (OPPs) in aqueous samples was described. Five kinds of commercially available fibers-7, 30 and 100 mum PDMS, 85 mum PA and 65 mum PDMS-DVB-were compared and 100 mum PDMS and 85 mum PA were the most sensitive fiber coatings for the analytes. The extraction time, extraction temperature, pH and content of NaCl were found to have significant influence on extraction efficiency. The optimized conditions were 100 mum PDMS fiber, 30 min extraction time at 40 degrees C, with 3% NaCl content and no pH adjustment. The linear range was 0.5-100 mug l(-1) for most of the analytes. The limits of detection (LODs) ranged from 0.049 mug l(-1) (for parathion) to 0.301 mug l(-1) (for carbophenothion) and RSD% of repeatability at the 10 mug l(-1) level were all below 8%. Environmental water samples were analyzed, but none of the analytes was detected. The recovery of spiked water samples was from 75.3 to 102.6%.

[Measurement of plasma fibronectin concentrations in normal pregnancy and pregnancy induced hypertension and its clinical significance].

Plasma fibronectin (Fn) concentrations were measured in 472 cases of normal pregnancy and pregnancy induced hypertension (PIH), and 50 cases of normal individuals using radioimmune turbidity method. The results showed that the mean value of Fn in 390 cases of normal pregnancy with various weeks of gestation was 445 +/- 159 mg/L significantly higher than the average of 299 +/- 76 mg/L in 50 cases of normal individuals and 250 +/- 89 mg/L in 22 cases of normal women. As pregnancy progressed, the plasma Fn value increased slightly. The 82 cases of PIH had an average plasma Fn level of 783 +/- 168 mg/L, which was significantly higher than that in normal pregnancy. If plasma Fn concentrition of 600 mg/L was used as cut-off point for the diagnosis of PIH, the sensitivity reached to 83%. Plasma Fn level increased as the disease of PIH progressed. Therefore, plasma Fn concentrition could be used as a reliable indicator to the severity of PIH.