The effects of <Emphasis Type="Italic">Acidithiobacillus ferrooxidans</Emphasis> on the leaching of cobalt and strontium adsorbed onto soil particles

Bioleaching from soil artificially contaminated with analogues of radionuclides, Co and Sr, was carried out using a Fe-oxidizing bacterium, Acidithiobacillus ferrooxidans. Due to bacterial metabolism, the pH and dissolved Fe³⁺ concentration in a biotic slurry decreased and increased respectively, over time, but the concentrations of Co and Sr extracted from the soil showed no significant enhancement compared with those under abiotic control. In both cases, Co and Sr were leached from the soil during the initial period of the experiment, due to the initially low solution pH of 2.0, and the dissolved concentrations remained almost constant for the duration of the experiment (300 h). Since oxidation of Fe²⁺ by A. ferrooxidans led to the production of Fe precipitates and colloidal suspensions, the Co and Sr extracted into solution were most likely re-adsorbed onto the Fe solids. Also, A. ferrooxidans, without an external supply of Fe²⁺, extracted almost equal or greater amounts of Co and Sr from the soil than when Fe²⁺ was supplied. Under the same leaching conditions, the extent of Sr removal was much lower than that of Co. On the contrary to the high efficiency of microbial metal leaching in biohydrometallurgy for low-graded sulfide ores, which has been widely documented, conventional bioleaching techniques with A. ferrooxidans supplied with enough Fe²⁺ showed low efficiency for the removal of radionuclides loosely bound onto soil particle surfaces.     

AFM probe based nano mechanical scribing of soda-lime glass

In recent years, demands for miniature components have increased due to their reduced size, weight and energy consumption. In particular, brittle materials such as glass can provide high stiffness, hardness, corrosion resistance and high-temperature strength for various biomedical and high-temperature applications. In this study, cutting properties and the effects of machining parameters on the ductile cutting of soda-lime glass are investigated through the nano-scale scratching process. In order to understand the fundamentals of the material removal mechanism at the atomic scale, such as machined surface quality, cutting forces and the apparent friction, theoretical investigation along with experimental study are needed. Scribing tests have been performed using a single crystal diamond atomic force microscope (AFM) probe as the scratching tool, in order to find the cutting mechanism of soda-lime glass in the nano-scale. The extended lateral force calibration method is proposed to acquire accurate lateral forces. The experimental thrust and cutting forces are obtained and apparent friction coefficients are deduced. The effects of feed rates and the ploughing to shearing transition of soda-lime glass have been investigated.     

Decarbonization of Vietnam’s economy: decomposing the drivers for a low-carbon growth

Environmental Science and Pollution Research - Vietnam has witnessed a rapid increase in national-level CO2 emissions due to rising urbanization, economic expansion, export growth, and industrial...     

Do first-trimester screening algorithms for preeclampsia aligned to use of preventative therapies reduce the prevalence of pre-term preeclampsia: A systematic review and meta-analysis

Objective

Traditional obstetric practice relies upon history-based assessment to screen for preeclampsia and guide preventative therapies but is hampered by low sensitivity, high false-positive rates and low treatment rates. First-trimester screening algorithms represent the most efficacious approach for risk prediction and could target early initiation of aspirin to well-defined high-risk populations. A large randomised controlled trial has demonstrated the clinical benefits of this approach, but widespread practice implementation has remained elusive.

Methods

We performed a systematic review and meta-analysis summarising studies linking first-trimester preeclampsia screening algorithms with the initiation of preventative therapy and examined their effect on pre-term preeclampsia rates compared with standard maternity care. Odds ratios were calculated together with 95% confidence intervals.

Results

7 studies with a total of 377,790 participants were included. Within singleton populations, early initiation of aspirin in response to a high-risk screening algorithm result reduced the prevalence of pre-term preeclampsia by 39% compared with routine antenatal care (odds ratio 0.61; 95% CI: 0.52–0.70). There were significant reductions in the prevalence of preeclampsia at <32–34 weeks, preeclampsia at any gestation and stillbirth.

Conclusion

First-trimester screening algorithms for preeclampsia aligned with early initiation of preventative therapy with aspirin reduce the prevalence of pre-term preeclampsia.     

Synergistic Effects of Combined Chlorine and Vitamin B1 on the Reduction of Murine Norovirus-1 on the Oyster (Crassostrea gigas) Surface

This study investigated the synergistic effects of combined chlorine (200, 500, 700, and 1000 ppm) and vitamin B₁ (1000, 2000, and 3000 ppm) on the murine norovirus-1 (MNV-1), a human norovirus (NoV) surrogate, on oyster surface. Vitamin B₁ slightly reduced MNV-1 (0.04–0.3 log-reduction), whereas chlorine significantly reduced MNV-1 (0.4–1.0 log-reduction). The combined chlorine and vitamin B₁ resulted in a 0.52–1.97 log-reduction of MNV-1. The synergistic reduction in the MNV titer was not dependent on the concentrations of chlorine and vitamin B₁, and it ranged between 0.08 and 1.03 log₁₀ PFU/mL. The largest synergistic reduction observed was for the combined 700 ppm chlorine and 1000 ppm vitamin B₁. The pH and mechanical texture of the oysters were not significantly changed by the combined 0–1000 ppm chlorine and 3000 ppm vitamin B₁. The overall sensory acceptability were significantly (P < 0.05) reduced in oysters treated with 1000 ppm chlorine and 3000 ppm vitamin B₁ than in those treated with 0–700 ppm chlorine and 3000 ppm vitamin B₁. This study suggests that the combined 700 ppm chlorine and 3000 ppm vitamin B₁ could potentially be used to reduce NoV on oyster surface without causing concomitant changes in the mechanical texture, pH, or sensory qualities of the oysters.

     

Silica-quaternary ammonium “Fixed-Quat” nanofilm coated fiberglass mesh for water disinfection and harmful algal blooms control

Intensification of pollution loading worldwide has promoted an escalation of different types of disease-causing microorganisms, such as harmful algal blooms(HABs), instigating detrimental impacts on the quality of receiving surface waters. Formation of unwanted disinfection by-products(DBPs) resulting from conventional disinfection technologies reveals the need for the development of new sustainable alternatives. Quaternary Ammonium Compounds(QACs) are cationic surfactants widely known for their effective biocidal properties at the ppm level. In this study, a novel silica-based antimicrobial nanofilm was developed using a composite of silica-modified QAC(Fixed-Quat) and applied to a fiberglass mesh as an active surface via sol–gel technique. The synthesized Fixed-Quat nanocoating was found to be effective against E. coli with an inactivation rate of 1.3 × 10~(-3) log reduction/cm min. The Fixed-Quat coated fiberglass mesh also demonstrated successful control of Microcystis aeruginosa with more than 99% inactivation after 10 hr of exposure.The developed antimicrobial mesh was also evaluated with wild-type microalgal species collected in a water body experiencing HABs, obtaining a 97% removal efficiency. Overall,the silica-functionalized Fixed-Quat nanocoating showed promising antimicrobial properties for water disinfection and HABs control, while decreasing concerns related to DBPs formation and the possible release of toxic nanomaterials into the environment.     

Monitoring biofouling based on aerobic respiration in reverse osmosis system

A monitoring method of biofouling in reverse osmosis (RO) system was proposed based on the fluorescent signal of resorufin, which is reduced by nicotinamide adenine dinucleotide released from viable cells during aerobic respiration. The fluorescent signal of resorufin reduced by planktonic cells and microorganisms of biofilm showed linearity, indicating its feasibility to monitor biofouling in a RO system. For the application of the method to the lab-scale RO system, the injection concentration of resazurin and the injection flow rate were optimized. Biofilm on RO membranes continuously operated in a lab-scale RO system was estimated by resorufin fluorescence under optimized detection condition. As a result, resorufin fluorescence on RO membrane showed a significant increase in which the permeability of RO system decreased by 30.48%. Moreover, it represented the development of biofilm as much as conventional biofilm parameters such as adenosine triphosphate, extracellular polymeric substances, and biofilm thickness. The proposed method could be used as a sensitive and low-cost technology to monitor biofouling without autopsy of membranes.     

Molecular approaches for the detection and monitoring of microbial communities in bioaerosols: A review

Bioaerosols significantly affect atmospheric processes while they undergo long-range vertical and horizontal transport and influence atmospheric chemistry and physics and climate change. Accumulating evidence suggests that exposure to bioaerosols may cause adverse health effects, including severe disease. Studies of bioaerosols have primarily focused on their chemical composition and largely neglected their biological composition and the negative effects of biological composition on ecosystems and human health. Here, current molecular methods for the identification, quantification, and distribution of bioaerosol agents are reviewed. Modern developments in environmental microbiology technology would be favorable in elucidation of microbial temporal and spatial distribution in the atmosphere at high resolution. In addition, these provide additional supports for growing evidence that microbial diversity or composition in the bioaerosol is an indispensable environmental aspect linking with public health.     

Pre-sampling contamination of filters used in measurements of airborne (1 → 3)-β-D-glucan based on glucan-specific Limulus amebocyte lysate assay

Air sampling for (1 → 3)-β-D-glucan may be a good method for assessing inhalation exposure to airborne fungi. Pre-sampling contamination of filter media used for sampling (1 → 3)-β-D-glucan may lead to substantial exposure measurement errors. Using the Limulus amebocyte lysate assay, we tested for pre-sampling levels of (1 → 3)-β-D-glucan on three types of filters-mixed cellulose ester (MCE)[1 brand], glass fiber (GF)[1 brand], and polycarbonate (PC)[5 brands]. Levels of (1 → 3)-β-D-glucan on MCE filters exceeded 4586.1 pg per filter. Levels on GF filters averaged 135.3 (± 28.9) pg per filter (range = 94.8-160.4 pg per filter) and levels on PC filters averaged 152.4 (± 236.1) pg per filter (range = non-detectable-1760.7 pg per filter). Efforts to clean MCE and GF filters were unfeasible or unsuccessful. Sonicating PC filters for two hours in ethanol, followed by a wash in pyrogen-free water, effectively eliminated measured levels of (1 → 3)-β-D-glucan on four brands of PC filters, as compared to untreated PC filters. This pretreatment process did not appear to physically damage the PC filters. Air sampling results highlighted the potentially problematic contamination of untreated PC filters. Ensuring that sampling media are free of (1 → 3)-β-D-glucan before sampling is crucial to accurately measure levels of (1 → 3)-β-D-glucan exposure, especially in environments where levels of (1 → 3)-β-D-glucan are low.     

Estimation of mercury speciation in soil standard reference materials with different extraction methods by ion chromatography coupled with ICP-MS

Analytical methods for the speciation of mercury, based on microwave extraction and sonication extraction, have been tested to determine the inorganic mercury and methyl mercury contents in two standard soil reference materials: SRM 2710 Montana Soil and BCR 580 estuarine sediment. Prior to applying the speciation extraction methods, the mineral compositions were analyzed via XRD analysis, with SRM 2710 shown to be composed mostly of aluminum silicate minerals, while carbonate minerals were the major constituent in BCR 580. Two extraction methods, microwave and sonication, were tested for the analysis and recovery efficiency of total mercury. The accuracy and efficiency of each extraction method was also compared. In the analysis of total mercury, the microwave extraction method, with using methanol and HCl as extractants, was better for SRM2710, while the application of the sonication extraction method was more efficient for the calcite-based BCR 580. The results showed good separation and recovery efficiencies, with values reaching 100% of those estimated. The sonication method was selected for the speciation of mercury, especially in BCR 580. An extraction solution comprising of a 1:1 mixture of methanol and HCl was used for the sonication extraction of BCR 580, with the resulting extractants analyzed by IC-HG-ICP-MS for methyl mercury and inorganic mercury. As a simple, rapid, sensitive, and accurate method, sonication extraction was found to be satisfactory.