A Narrative Review of Norovirus Gastroenteritis: More Global Attention Is Needed

Noroviruses (NoVs), an important pathogenic agent of foodborne illness, lead to acute and chronic gastroenteritis in humans of all ages and to travelers’ diarrhea. Many genotypes exist in nature; GII.4 is widely known as the most predominant. Outbreaks mostly occur in semi-closed settings. Although the disease is self-limited to person, many cases have resulted in death, which has raised more concerns. However, a lack of microbial culture techniques limits research and thus knowledge about these viruses. To date, there are no specific antiviral drugs that fight NoVs. Rehydration is the ideal approach at present for severe cases. The only way to prevent infection is to improve personal hygiene. So many variants and ambiguous evolution mechanisms make research for a vaccine much more difficult. In recent years, several vaccine candidates entered pre-clinical development. This review concentrates on summarizing the aspects of NoV structure, culture, genetic evolution, and the vaccine

Seroprevalence of Pandemic (H1N1) 2009 in Pregnant Women in China: An Observational Study

BACKGROUND: We investigated the seropositive rates and persistence of antibody against pandemic (H1N1) 2009 virus (pH1N1) in pregnant women and voluntary blood donors after the second wave of the pandemic in Nanjing, China. METHODOLOGY/PRINCIPAL FINDINGS: Serum samples of unvaccinated pregnant women (n = 720) and voluntary blood donors (n = 320) were collected after the second wave of 2009 pandemic in Nanjing. All samples were tested against pH1N1 strain (A/California/7/2009) with hemagglutination inhibition assay. A significant decline in seropositive rates, from above 50% to about 20%, was observed in pregnant women and voluntary blood donors fifteen weeks after the second wave of the pandemic. A quarter of the samples were tested against a seasonal H1N1 strain (A/Brisbane/59/2007). The antibody titers against pH1N1 strain were found to correlate positively with those against seasonal H1N1 strain. The correlation was modest but statistically significant. CONCLUSIONS AND SIGNIFICANCE: The high seropositive rates in both pregnant women and voluntary blood donors suggested that the pH1N1 virus had widely spread in these two populations. Immunity derived from natural infection seemed not to be persistent well

Study on Biodegradation Characteristics of Industrial Phenol-Containing Wastewater by Biological Co-Metabolism Technology

Biological co-metabolism is an economical and efficient technique for treating refractory organic matter, and in recent years, it has been widely used in the treatment of chlorophenol-containing wastewater. It has been found that many conditions affect the bio co-metabolism efficiency, such as the carbon source type, carbon source content, microorganism types, and environmental factors. The carbon source concentration experiment showed that when the dosage ratio of sodium acetate to black aniline powder was 1:2, the degradation rate of black aniline powder was 82%, and the removal rate was 92.9%. When tetrachlorophenol increased from 210 mg/L to 2100 mg/L, the tetrachlorophenol was increased in the effluent, and the microorganism's activity was inhibited. Besides, the sedimentation performance of activated sludge was also damaged. The temperature test showed that the removed 4-chlorophenol was as high as 2100 mg/L at 35 °C, and the apparent 4-chlorophenol residue in the effluent could be detected at 20 °C. Therefore, by appropriately controlling the external operating conditions of the reactor, the co-metabolism of refractory organic such as chlorophenols can be achieved

Research of advanced treatment technologies for chlorophenol wastewater

Chlorophenol wastewater belongs to highly toxic industrial wastewater, which can cause serious harm to the environment and human health if not treated effectively. The current treatment methods for chlorophenol wastewater are divided into physical, chemical, and biological methods. The physical adsorption experiment found that the monodisperse magnetic nano-column was prepared by the solvothermal method, which could remove 91.5% of pentachlorophenol within 30 mins. More than 90% of chlorophenol can be extracted using an ionic liquid as an extractant. When the chlorophenol reaches 15 g/L, the extraction rate only slightly decreases. CaO and SiO2 can achieve 99.0% 2,4,6-trichlorophenol in 6 hours as ball milling materials by physical and chemical methods. The electrochemical reduction test found that using Pd/Py SDBS/Ti as the cathode, 2-chlorophenol, 4-chlorophenol, and 3-chlorophenol could be reduced and dechlorinated, in which 100 mg/L of 2-chlorophenol could be completely degraded within 60 minutes. The biochemical index BOD5/COD of wastewater is less than 0.3 if the biological treatment technology based on co-metabolism is adopted to realize the chlorophenol treatment. In treating chlorophenol wastewater, the application scenario should be fully considered to achieve the best treatment effect of chlorophenol wastewater

Research progress of the non-point source pollution-based rainwater treatment technologies for urban and agricultural

Currently, the treatment of point source pollution has been basically com-pleted, and the development of non-point source pollution(NPP) has become a new threat to natural water. Unlike point source pollution, NPP is much more complex than point source pollution in terms of treatment difficulty and treatment measures. Therefore, NPP has gradually become the focus of researchers’ attention. This paper mainly reviews the current research status on the governance of NPP, precisely urban source and agricultural source pollution governance. In addition, the article reviews the treatment measures of NPP at the present stage, from source treatment, process blocking and end-of-pipe treatment. This thesis provides a more comprehensive overview of NPP treatment measures, which can provide a reference for further research and development of engineering practices on NPP

Defect evolution during high temperature tension-tension fatigue of SLM AISi10Mg alloy by synchrotron tomography

Lack of fusion defects and porosity are inevitable characteristics of additive manufacturing and these are expected to play a key role in determining fatigue life and fatigue failure when excluding the influence of inhomogeneous microstructures. This work followed damage accumulation under tension-tension cyclic loading at 250 °C in situ by time-lapse synchrotron radiation X-ray micro-computed tomography (SR-μCT) for AlSi10Mg test-pieces, produced by selective laser melting (SLM) over their complete fatigue lives (ranging from 180 to 38,000 cycles). These samples were found to accumulate widespread plastic strain each cycle in common with ultra-low cycle fatigue (UCLF) at low levels of triaxial constraint. The defects were found to elongate plastically at a rate approximately 10 times larger than their growth rate laterally. This elongation behaviour at room and elevated temperature fatigue is proportional to the accumulated longitudinal strain increment each cycle. Rotation under the influence of shear is also observed for those defects close to the surface of samples. Some defect coalescence was observed, but final failure was found to be associated with the nucleation of a high density of secondary microvoids (occurring at eutectic Si platelets) that form just prior to failure and link up by microvoid coalescence. These steps may take up approximate 90% of the fatigue life. The final stage of cyclic plasticity occurs when the longitudinal strain exceeds ∼0.9. Our results are in line with previous models of strain accumulation and defect growth under ULCF conditions

Performance evaluation of a typical sewage system remediation project in Yangtze River protection

The Yangtze River protection is an important environmental protection strategy for China, and the quality and efficiency of the sewage system is also one of the environmental protection actions that China is working hard to implement in recent years. As the first batch of pilot cities for the protection of the Yangtze River, Wuhu City has significantly improved its sewage system through a series of comprehensive sewage system improvement engineering measures. This paper briefly described the general situation and measures of the sewage system renovation project in the CD area of Wuhu City, and based on the systematic thinking of “source-network-plant-river”, the performance of improving the quality and efficiency of the sewage system was evaluated. With the implementation of the sewage system remediation project, the water quality at the source and discharge outlet as well as the water quantity of sewage collected had been greatly improved. The sewage collection volume had been increased from 10,000 m3/d to 42,000 m3/d and the COD concentration of the influent has increased significantly. The introduction and analysis of this project may provide some reference for other similar sewage system remediation projects in China and other countries and regions