Biosorption of lead(II) from aqueous solution by lactic acid bacteria.

The biosorption of Pb(II) from aqueous solutions by lactic acid bacterium, Lactobacillus brevis, was studied. The effects of initial pH, contact time, initial Pb(II) concentration, bacterial concentration, rotation speed and temperature of biosorption of Pb(II) from aqueous solutions were investigated. The optimal condition for Pb2+ ions adsorption was observed at pH 6, with the rotational speed of 120 rpm.min-1, bacterial concentration of 3 g.L-1, temperature of 40 °C and contact time of 12 h. The correlation regression coefficients showed that the biosorption process can be well fitted with the Redlich-Peterson, Langmuir, Freundlich and Temkin isotherm models. The equilibrium adsorption capacity reached 53.632 mg.g-1. Binding energy value was 0.264 kJ/mol, which indicated that the adsorption process seemed to involve chemisorption and physisorption. Kinetics of adsorption was found to fit well with the pseudo-second-order and Elovich kinetic equations. Thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of adsorption.

Electrically reversible cracks in an intermetallic film controlled by an electric field.

Cracks in solid-state materials are typically irreversible. Here we report electrically reversible opening and closing of nanoscale cracks in an intermetallic thin film grown on a ferroelectric substrate driven by a small electric field (~0.83 kV/cm). Accordingly, a nonvolatile colossal electroresistance on-off ratio of more than 108 is measured across the cracks in the intermetallic film at room temperature. Cracks are easily formed with low-frequency voltage cycling and remain stable when the device is operated at high frequency, which offers intriguing potential for next-generation high-frequency memory applications. Moreover, endurance testing demonstrates that the opening and closing of such cracks can reach over 107 cycles under 10-µs pulses, without catastrophic failure of the film.

[Extracapsular dissection versus superficial parotidectomy for treatment of parotid benign tumors: evidence based medicine analysis].

Objective:The aim of this study is to systematically assess the clinical outcomes of extracapsular dissection (ECD) and superficial parotidectomy (SP), and to provide evidences for the clinical decision for treatment of parotid gland benign tumors. Method:Relevant studies that compared the outcomes of extracapsular dissection and superficial parotidectomy for the parotid benign tumors were searched in Pubmed, CNKI and Wangfang data databases, and Meta-analysis was performed using software RevMan 5.0. Result:Fifteen studies were selected for the Meta-analysis. A total of 2 929 participants were included in those studies, of which 1 796 underwent ECD and 1 133 underwent SP. The recurrence rates for ECD and SP were 1.29% (23 of 1 776 cases) and 1.48% (16 of 1 081 cases), respectively. There were no statistically significant in recurrence rate between ECD and SP. The rates of transient facial nerve paresis for ECD and SP were 5.48% (74 of 1 350) and 22.94% (139 of 606), that of permanent facial nerve paralysis were 0.66% (8 of 1 221) and 2.71% (15 of 554). The incidences of Frey's syndrome in ECD group and SP group were 1.91% (26 of 1 360) and 16.71% (111 of 664), that of fistula in were 0.53% (5 of 946) and 2.96% (10 of 338). ECD could reduce the risk for complications compared with SP. Conclusion:This systematic review with Meta-analysis suggests that ECD has a similar recurrence rate as SP with fewer postoperative complications. ECD may be considered as an alternative surgical modality for select benign parotid tumor.

Combining ultrasound and lactobacilli treatment for high-fat-diet-induced obesity in mice.

Chronic systemic lipopolysaccharide-induced inflammation can cause obesity. In animal experiments, lactobacilli have been shown to inhibit obesity by modifying the gut microbiota, controlling inflammation and influencing the associated gene expression. A previous study found that high-fat-diet-induced (HFD) obesity was suppressed by lactobacilli ingestion in rats via the inhibition of parasympathetic nerve activity. This study explored the combined use of lactobacilli ingestion and ultrasound (US) to control body weight and body fat deposition in HFD mice over an 8-week experimental period. Male C57BL/6J mice received an HFD during treatment and were randomly divided into four groups: (i) control group (H), (ii) lactobacilli alone (HB), (iii) US alone (HU) and (iv) lactobacilli combined with US (HUB). The US was targeted at the inguinal portion of the epididymal fat pad on the right side. At the 8th week, body weight had decreased significantly in the HUB group (15.56 ± 1.18%, mean ± SD) group compared with the HU (26.63 ± 0.96%) and H (32.62 ± 5.03%) groups (p < 0.05). High-resolution microcomputed tomography (micro-CT) scans revealed that the reduction in total body fat volume was significantly greater in the HUB group (69%) than in the other two experimental groups (HB, 52%; HU, 37%; p < 0.05). The reductions in the thickness of the subcutaneous epididymal fat pads were significantly greater in the HUB group (final thickness: 340 ± 7 µm) than in the H (final thickness: 1150 ± 21 µm), HB (final thickness: 1060 ± 18 µm) and HU (final thickness: 370 ± 5 µm) groups (all p < 0.05). Combination therapy with lactobacilli and US appears to enhance the reduction in body weight, total and local body fat deposition, adipocyte size and plasma lipid levels over an 8-week period over that achieved with lactobacilli or US alone in HFD mice. These results indicate that US treatment alone can reduce hyperlipidemia in HFD mice.

Stepwise work hardening induced by individual grain boundary in Cu bicrystal micropillars.

Vast experiments have demonstrated that the external specimen size makes a large difference in the deformation behavior of crystalline materials. However, as one important kind of internal planar defects, the role of grain boundary (GB) in small scales needs to be clarified in light of the scarce and inconsistent experimental results at present. Through compression of Cu bicrystal and its counterpart monocrystal micropillars, it is found that, in contrast to the monocrystals, the bicrystals are characterized by work hardening with discrete strain bursts. Interestingly, the stress rise between two adjacent strain bursts of the bicrystals increases with the decrease of specimen size. The results suggest that GBs play a critical role in the work hardening of materials in small scales, which may provide important implications to further understand the general work hardening behaviors of materials in the future.

Clinical presentation of acute mastoiditis in children.

Nineteen children with 21 episodes of acute mastoiditis were treated in our hospital from 1989 to 1998. The diagnosis was based on physical, radiologic, and surgical findings. The affected children were aged from 1 year old to 17 years old, with the peak incidence at 4 years old (23.8%). Postauricular pain (90.5%) and fever (81%) were the most common harbingers of incipient acute mastoiditis. Streptococcus pneumoniae (38.1%) was the most common organism isolated followed by Pseudomonas aeruginosa (23.8%). Underlying diseases such as leukemia and myeloid metaplasia were found in 38.6% of patients. All of the patients were initially treated with intravenous antibiotics during hospitalization. Six patients were managed with an adjunctive drainage procedure such as myringotomy or mastoidectomy. The most common complication of acute mastoiditis was hearing loss (31.6%); the second was meningitis (21.1%). Subperiosteal abscess was found in two patients and brain abscess in one. Although acute mastoiditis is an uncommon condition, early diagnosis and management are necessary to prevent more serious complications.

Total sialic acid as a tumor marker for oral cancer.

Serum sialic acid levels were measured in 80 healthy subjects, in 60 patients with benign tumors and in 110 patients with oral cancer. It was shown that these levels were significantly elevated in oral cancer patients compared to healthy controls and patients with benign tumors (p < 0.01); they were higher in patients with stage III and stage IV disease than in those with stage I and II disease (p < 0.01). However, no difference was observed between healthy controls and stage I and II cancer patients. The results of this study suggest that the determination of sialic acid levels may be of value in the diagnosis of oral cancer, but its usefulness as an adjunct in clinical staging is limited.

[Analysis of proteins and antigens in nine strains of Toxoplasma gondii by means of SDS-PAGE and immunoblotting].

The proteins and antigens of nine strains of Toxoplasma gondii were analyzed by SDS-PAGE and immunoblotting. These strains including RH strain, Zs-2 strain, CN strain and SH1, SH2, SH3, SH4, SH5, SH8 strains, were obtained from other laboratories or isolated from deformity fetus in our laboratory. SDS-PAGE analysis revealed that these strains were very close in the major bands of proteins and differences were observed only in part. There were common components in antigens of all strains using IgG antibody prepared from high-titre rabbit antisera raised against RH strain of Toxoplasma.

[Detection of circulating antigen in urine from mice infected with Toxoplasma tachyzoites].

Urine samples collected from three groups of mice infected experimentally with different numbers doses of Toxoplasma trophozoites were detected for the presence of Toxoplasma circulating antigen by using fast ELISA. The results showed that presence of circulating antigen in all three infected groups of mice in comparison with the normal control group. Toxoplasma circulating antigen was detected on days 5, 4 and 3 after infection in light-, moderate- and heavy-infection groups, respectively. The concentration of circulating antigen was on a parallel with the duration of infection. Western blot analysis of the Toxoplasma circulating antigen in urine revealed the existence of seven specific bands with molecular weights of 75, 67, 55, 43, 30, 28 and 22 kDa.

[The examination of pyruvate and erythrocyte transketolase activity in the blood of patients with chronic alcoholic nervous disease].

To study the laboratory and mechanism of chronic alcoholic nervous disease (CAND), we have examined pyruvate and erythrocyte transketolase activity (E-TKA) in the blood of 20 patients with CAND with normal subjects as controls Then, they were treated with vitamin B. The results were: 1. the level of pyruvate in the blood of the patients with CANE was higher than that of the controls. The E-TKA in the blood of the patients with CAND was lower than that of the controls. There was significant difference in both the two indexes between the two groups, 2. After treatment, the syndromes of the patients were obviously relieved. The pyruvate and E-TKA in the blood of the patients returned to normal. It proves that: 1. the vitamin B in the body of the patients with CAND was lower than that of normal people. 2. the pyruvate and E-TKA in the patients' blood may be taken as laboratory indexes of the CAND. 3. The examination of E-TKA may be preclinical diagnosis to CAND. 4. CAND is mainly caused by vitamin B deficiency.