[Health status of dust-exposed workers in a precision casting enterprise].

Objective: To investigate the health status of workers exposed to zircon sand and silica dust in a precision casting enterprise, and to provide a basis for the development of prevention and control measures. Methods: Occupational health examination, questionnaire survey, and field investigation of occupational health were performed for 176 male workers (18 workers in the zirconium dust exposure group, 109 in the non-zirconium dust exposure group, and 49 in the non-dust exposure group) in a precision casting enterprise, and a statistical analysis was performed for the data obtained. Results: Dust and noise were major hazard factors for occupational diseases in this enterprise. The abnormal rate of physical examination was 71.02%. Compared with the non-zirconium dust exposure group, the zirconium dust exposure group had significantly higher detection rates of restrictive ventilatory dysfunction, increased immunoglobulin IgE, increased alanine aminotransferase, and increased alkaline phosphatase (ALP) (P<0.05) ; compared with the non-dust exposure group, the zirconium dust exposure group had a significantly higher detection rate of increased ALP (P<0.05) . Of all workers, 15 were found to have pneumoconiosis-like changes (11 had pneumoconiosis and 4 needed observation) , among whom 4 were in the zirconium dust exposure group (3 had pneumoconiosis and 1 needed observation) and 11 were in the non-zirconium dust exposure group (8 had pneumoconiosis and 3 needed observation) . The detection rate of pneumoconiosis-like changes showed no significant differences between the two groups (20.22% vs 10.09%) . Conclusions: There was a severe dust hazard in this enterprise. Inhalation of dust containing zirconium is associated with respiratory system injury, especially the development of pneumoconiosis, and it may also cause immune dysfunction and liver impairment.

Fine structure characterization of martensite/austenite constituent in low-carbon low-alloy steel by transmission electron forward scatter diffraction.

Transmission electron forward scatter diffraction and other characterization techniques were used to investigate the fine structure and the variant relationship of the martensite/austenite (M/A) constituent of the granular bainite in low-carbon low-alloy steel. The results demonstrated that the M/A constituents were distributed in clusters throughout the bainitic ferrite. Lath martensite was the main component of the M/A constituent, where the relationship between the martensite variants was consistent with the Nishiyama-Wassermann orientation relationship and only three variants were found in the M/A constituent, suggesting that the variants had formed in the M/A constituent according to a specific mechanism. Furthermore, the Σ3 boundaries in the M/A constituent were much longer than their counterparts in the bainitic ferrite region. The results indicate that transmission electron forward scatter diffraction is an effective method of crystallographic analysis for nanolaths in M/A constituents.

Expression level and distribution of HMGB1 in Sombati's cell model and kainic acid-induced epilepsy model.

OBJECTIVE: Observe the expression and distribution of HMGB1 in Sombati's cell model and kainic acid-induced epileptic rats' model. MATERIALS AND METHODS: Dissociated hippocampal neurons from neonatal SD rats and cultured those for 9 days, then changed medium to Mg2+-free medium for 3 hours to induce Sombati's cell model. The expression level of HMGB1 in the neurons was detected at 24h and 72h by Western Blotting. Appropriate kainic acid was injected into the lateral ventricles to induced epileptic rats' model in vivo trial, the expression level and distribution of HMGB1 at 24h and 72h were established by immunohistochemistry. RESULTS: The expression level of HMGB1 showed significantly different between model group and control group both in vitro and in vivo trials. At 24h, the expression level of HMGB1 in the model group was lower than the control group (p < 0.05), and became higher than the control group at 72h (p < 0.05). From the in vivotrial, a nucleus-to-cytoplasm translocation was also discovered. CONCLUSIONS: This investigation indicates that HMGB1 plays a crucial role in the pathophysiology of epilepsy, by altering its quantity and distribution.

Molecular characterization of Cryptosporidium spp. in pre-weaned calves in Shaanxi Province, north-western China.

Cryptosporidium, a worldwide protozoan parasite, is one of the most common causes of diarrhoea in humans and animals. The aim of the present study was to determine Cryptosporidium species/genotypes in pre-weaned calves in Shaanxi Province using PCR and sequencing based on the small subunit rRNA gene. A total of 258 faecal samples were collected from pre-weaned calves in 19 different farms from six areas in Shaanxi Province, north-western China. Cryptosporidium infection was detected in 14 of 19 farms (73.7 %), with a total prevalence of 20.2 % (52/258). Both dairy and Qinchuan (beef) cattle were found with Cryptosporidium infection. Three Cryptosporidium species, namely Cryptosporidium bovis (n = 26), Cryptosporidium andersoni (n = 14) and Cryptosporidium ryanae (n = 12), were detected in pre-weaned calves in Shaanxi Province, with C. bovis (in 12 farms) identified as the most common species on cattle farms. Two additional and previously unknown C. ryanae genotypes, CRTypes III and IV, were observed in the present study. However, the zoonotic species, Cryptosporidium parvum, was not detected in this study, which suggested a low zoonotic potential in Cryptosporidium-infected pre-weaned calves in this province.

Structures and magnetism of two novel heptanuclear lanthanide-centered trigonal prismatic clusters: [LnCu6(mu 3-OH)3(HL)2(L)4](ClO4)2.25H2O (Ln = La, Tb; H2L = iminodiacetic acid).

The new heteronuclear iminodiacetic acid (H2L) complexes [LnCu6(mu 3-OH)3(HL)2(L)4](ClO4)(2).25H2O with Ln = La (1) and Tb (2) have been prepared in aqueous solution and characterized by single-crystal X-ray diffraction to be isomorphous (crystallographic data for 1 and 2: hexagonal, P63/m; a = b = 12.6425(14) A, c = 24.541(5) A, Z = 2 (1); a = b = 12.5802(9) A, c = 24.285(4) A, Z = 2 (2)). Ln3+ was found to be located in the center of the trigonal prismatic cage formed by six Cu2+ ions, with a tricapped trigonal prismatic coordination environment of nine O atoms. The magnetic properties of complexes 1 and 2 have been studied. The results indicate the presence of ferromagnetic couplings between Tb3+ and Cu2+ in compound 2.

Ultrafast optical pulse digitization with unary spectrally encoded cross-phase modulation.

A method to digitize the intensity of ultrashort laser pulses for high-speed optical signal processing is described. This digitization was based on the spectral broadening of a weak probe (carrier) pulse by a more intense pump (signal) pulse through the nonlinear optical process of cross-phase modulation (XPM). The signal pulse intensity was varied to generate different spectral widths that can be encoded into digital form. Using a 50-ps time-divided multiplexing pulse train with a waveguide splitter, combiner, and an array of fibers with variable lengths, a unary XPM encoding approach is demonstrated. The spectral encoding scheme can be used to achieve a 5-GHz sampling rate at a 16-level accuracy.

Single-pulse degenerate-cross-phase modulation in a single-mode optical fiber.

Using a single ultrashort optical pulse propagating through a short nonbirefringent single-mode optical fiber, we have observed degenerate-cross-phase modulation of the two orthogonal circularly polarized components of the pulse. The spectral broadening of the two polarization components in the single laser pulse is attributed to self-phase modulation (SPM), degenerate-cross-phase modulation (DXPM), and interference between SPM and DXPM.

High-resolution spectra of cross-phase modulation in optical fibers.

Cross-phase-modulation (XPM) effects were investigated as a novel nondegenerate method to control the spectrum of an optical pulse. The oscillating substructures in the XPM spectra were measured with a high-resolution optical spectral analysis system. The dispersion of the third-order nonlinearity was obtained by measurement and analysis of the XPM and self-phase-modulation spectra of the probe and pump pulses at different wavelengths.

Pharmacokinetics of the combination pyrimethamine with sulfadoxine and mefloquine (FANSIMEF) in Chinese volunteers and the relative bioavailability of a lacquered tablet.

The oral single-dose pharmacokinetics and bioavailability of mefloquine (M) in combination with pyrimethamine (P) and sulfadoxine (S) from a single non-lacquered tablet (NL; M 250 mg, P 25 mg, S 500 mg) and two lacquered tablets (L; M 125 mg, P 12.5 mg, S 250 mg) were investigated in 6 healthy Chinese volunteers. The plasma concentrations of P and S were measured by high-performance liquid chromatography with UV detector over 11 days and the plasma concentrations of M were measured by gas chromatography with electron capture for 63 days. The pharmacokinetic evaluation of each of the three components was based on the assumption of an open linear one-compartment model. The model-independent pharmacokinetic parameters such as elimination half-life and total clearance of P and S in the present study were not appreciably different from those reported previously. The pharmacokinetic parameters of elimination half-life, total clearance and apparent volume of distribution of M were 11 days, 45.8 ml/h.kg, and 14.8 l/kg, respectively. Compared to previously published data on M in Thai patients, Caucasian, Brazilian and African subjects, it was found that the elimination half-life in Chinese subjects was similar to that in Thai patients, but different from Caucasian, Brazilian and African subjects. There were significant differences in total clearance and volume of distribution among Chinese subjects and Thai patients. The differences in pharmacokinetic behaviour of M between subject groups needs to be examined further. The relative bioavailability of P, S, and M in the lacquered and non-lacquered tablet formulations in the 6 subjects studied were not significantly different with values (mean +/- SD) of 0.98 +/- 0.06, 1.28 +/- 0.20 and 1.02 +/- 0.17, respectively.