Synthesis of a Novel Dithiocarbamate Surfactant Derivative Adsorbent for Efficient Removal of Heavy Metal Ions.

In this work, a novel heavy metal chelating agent (DTC-SDS) containing dithiocarbamate (DTC) was synthesized using sodium dodecyl sulfate (SDS), formaldehyde, and carbon disulfide. DTC-SDS has excellent trapping performance under pH 1-7 and initial concentrations 100-500 mg/L. With the increase in adsorbent dose, the adsorption amount of DTC-SDS increases and then decreases, and the optimized dosage of DTC-SDS is 0.02 g. The DTC-SDS adsorbent exhibits superior adsorption capacity (191.01, 111.7, and 79.14 mg/g) and high removal rates (97.99%, 98.48%, and 99.91%) for Mn2+, Zn2+, and Pb2+ respectively, in wastewater. Such remarkable adsorption performance could be attributed to the strong trapping effect on heavy metal ions by the C-S bond of DTC-SDS. The liquid adsorbent was in full contact with heavy metal ions, which further enhanced the complexation of heavy metal ions. The adsorption isothermal model showed that the adsorption process was typical of Langmuir monomolecular layer adsorption. Kinetic studies showed that the pseudo-second-order kinetic model fits the experimental adsorption data better than the pseudo-first-order kinetic model. In the ternary metal species system (Mn2+, Zn2+, and Pb2+), DTC-SDS preferentially adsorbed Pb2+ due to its highest covalent index. The main controlling step is the chemical interaction between the active groups of DTC-SDS and the heavy metal ions. This work provides valuable insights into the adsorption of heavy metal ions onto dithiocarbamate, which could guide the development of other heavy metal chelating agents and be beneficial for developing novel treatments of wastewater contaminated with heavy metals.

Efficacy and Safety of Repetitive Transcranial Magnetic Stimulation for Poststroke Memory Disorder: A Meta-Analysis and Systematic Review.

BACKGROUND: Patients with post-stroke memory disorder (PSMD) have poor quality of life and it is necessary to identify more beneficial stimulation protocols for treatment with repetitive transcranial magnetic stimulation (rTMS). This meta-analysis was conducted to investigate the efficacy and safety of rTMS for improving memory performance, global cognition, and activities of daily living (ADL) among patients with PSMD. METHODS: The PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang databases were screened to identify relevant randomized controlled trials. The primary outcome was memory performance; secondary outcomes included global cognition, ADL, and adverse events. STATA software was used to perform data synthesis. RESULTS: Five articles with a total of 192 participants were included. The results indicated that rTMS was superior to control treatments for improving memory performance (mean difference [MD] = 1.73, 95% CI [Confidence Interval] [0.85, 2.60], p < 0.001), global cognition (MD = 2.44, 95% CI [0.96, 3.93], p < 0.001), and ADL (MD = 10.29, 95% CI [5.10, 15.48], p < 0.001). No significant differences were found between the low-frequency (LF) and high-frequency (HF) rTMS subgroups (p = 0.47, I2 = 0.00%) or between the sham rTMS and non-rTMS subgroups (p = 0.94, I2 = 0.00%). Four studies did not reported adverse events. CONCLUSIONS: rTMS may improve memory function, global cognition, and the ability to perform ADL in patients with PSMD. LF-rTMS and HF-rTMS may have equal efficacy for treatment of PSMD. Future studies should consider extending the follow-up period to explore the safety and long-term efficacy of rTMS for treatment of PSMD and the appropriate choice of placebo for clinical trials of this treatment.

Prevalence and risk factors of Helicobacter pylori infection among children in Kuichong Subdistrict of Shenzhen City, China.

BACKGROUND: Helicobacter pylori infection is a significant burden to the public health in China as it can lead to various gastric diseases including peptic ulcers and gastric cancer. Since most infections occurred during childhood, it is therefore necessary to understand the prevalence and risk determinants of this bacterial infection in children. Herewith, we conducted a cross-sectional study in the Kuichong Subdistrict of Shenzhen City to assess the prevalence and risk factors of H. pylori infection among children. METHODS: From September 2018 to October 2018, 1,355 children aged 6-12 years from four primary schools in the Kuichong Subdistrict of Shenzhen City were recruited. These children were screened for H. pylori infection using the 13C-urea breath test. In addition, parents were requested to fill out a standardized questionnaire. The chi-square test and multivariable logistic regression analysis were used to identify risk factors for H. pylori. RESULTS: Among 1,355 children recruited in this study, 226 (16.7%; 95% CI [14.7-18.7]) were positive of H. pylori infection. Multivariable logistic regression analysis identified six factors significantly associated with H. pylori infection children including parent(s) with tertiary education level (OR: 0.64; 95% CI [0.46-0.89]), testing bottle feed temperature using the mouth (OR: 1.79; 95% CI [1.19-2.68]), sharing of cutlery between the feeding person and young children during meals (OR: 1.84; 95% CI [1.22-2.78]), eating fruit after peeling (OR: 2.56; 95% CI [1.4-4.71]), frequent dining out (OR: 3.13; 95% CI [1.46-6.68]) and snacking (OR: 1.43; 95% CI [1.01-2.01]). CONCLUSIONS: Overall, better educated parent(s) played a protective role against the acquisition of H. pylori infection in children. Testing bottle feed temperature using the mouth, cutlery sharing between the feeding person and young children, and snacking posed a lower but significant risk for H. pylori infection. Only eating peeled fruits and frequent dining out were associated with greater infection risks.