Study on the Damage of Fiber-Reinforced Seawater Sea Sand Concrete by Freezing and Thawing of Seawater.

The use of seawater and sea sand as replacements for fresh water and river sand in the preparation of seawater and sea sand concrete can effectively address issues such as high transportation costs, extended construction periods, and resource wastage. Nevertheless, in northern coastal areas, the problem of concrete durability in the complex and changing marine environment is more prominent. Research on the durability of seawater sea sand concrete is beneficial to the widening of its application range. To investigate the impact of glass fiber (GF) and polyvinyl alcohol fiber (PVA) with different blending methods on the seawater freeze-thaw resistance of seawater sea sand concrete (SSC), corresponding specimens were prepared, and seawater freeze-thaw cycling tests were conducted. By adopting the slow-freezing method and combining macro-structure and micro-morphology, the damage mechanism and the deterioration law of fiber-reinforced SSC under seawater freezing and thawing were investigated. The results indicate that, macroscopically, the incorporation of GF and PVA can effectively mitigate the damage to the matrix and reduce the effects of external erosive substances on the rate of strength loss, the rate of mass loss, and the relative dynamic elastic modulus. After 75 cycles, the SSC with a total volume doping of 0.3% and a blending ratio of 1:1 showed a 41.23% and 27.55% reduction in mass loss and strength loss, respectively, and a 29.9% improvement in relative dynamic elastic modulus compared with the basic group. Microscopic analysis reveals that the combined effect of freezing and expansion forces, the expansive substances generated by seawater intrusion into the interior of the matrix, and salt crystallization all weaken the bond between aggregate and mortar, leading to accelerated deterioration of the concrete. The incorporation of fibers enables the matrix to become denser and improves its crack-resistant properties, resulting in a better durability than that of the basic group. The damage prediction model established by the NSGM(1,N) model of gray system theory exhibits high accuracy and is suitable for long-term prediction, accurately predicting the damage of seawater sea sand concrete under seawater freeze-thaw coupling.

Study on the Bonding Performance of BFRP Bars with Seawater Sand Concrete.

A total of 66 sets of pullout specimens were prepared to investigate the bonding properties of basalt fiber-reinforced polymer reinforcement (hereinafter referred to as BFRP) with seawater sand concrete (hereinafter referred to as SSC). The volume dosages of mono-doped glass fibers and mono-doped polypropylene fibers were 0.1%, 0.2%, and 0.3%; the total volume dosage was set to be constant at 0.3%; and the doping ratios of the hybrid fibers were 1:2, 1:1, and 2:1. The effect on the bonding performance of BFRP reinforcement with SSC was studied on the condition of the diameter D of the BFRP reinforcement being 12 mm; the bond length of SSC being 3D, 5D, and 7D; and the surface characteristics of the reinforcement being sandblasted and threaded. The research showed that due to internal cracks in the matrix, salt crystals in the pores, chloride salts with high brittleness and expansion, as well as sulfate corrosion products such as "Frederick salts" in SSC, the concrete became brittle, resulting in more brittle splitting failures during the pullout test. Doped fibers can increase the ductility effect of concrete, but the bonding effect between the threaded fiber reinforcement and the SSC was not as good as that of the sandblasting group. When the bond length was 5D, the bonding effect between the BFRP reinforcement and SSC was the best, and the bonding performance of the experimental group with doped fibers was better than that of the threaded group. Finally, by combining the ascending segment of the Malvar model with the descending segment of the improved BPE model, a constitutive relationship model suitable for the bond-slip curve between BFRP reinforcement and SSC was fitted, which laid a theoretical foundation for future research on SSC.

Diagnosis, Treatment, and Associated Factors Among Patients with HCV Infection - Jiangsu Province, China, 2004-2020.

What is already known on this topic?: The global efforts to address the hepatitis C virus (HCV) are progressing, but there are still significant gaps in the diagnosis and treatment of HCV, leading to an increasing number of deaths related to HCV. What is added by this report?: An extensive investigation was conducted to assess HCV RNA diagnosis, treatment uptake, and associated factors among individuals infected with HCV within Jiangsu Province. The study encompassed a large geographical area and utilized a substantial sample size. What are the implications for public health practice?: Implementing focused interventions to improve the timely diagnosis of HCV RNA and increase the uptake of HCV treatment could effectively reduce the future burden of HCV-related health problems, deaths, and healthcare expenses. This is essential for achieving the global target of eliminating hepatitis C.

Performance Analysis and Admixture Optimization of GBFS-HPMC/Fiber Pervious Concrete.

Permeable pavements can decrease the volume of stormwater, thereby mitigating the risk of flooding and reducing the urban heat island effect. This study investigated the influence of incorporating granulated blast-furnace slag (GBFS), hydroxypropyl methylcellulose (HPMC), and polypropylene plastic textile fiber (PPTF) on the mechanical properties and water permeability of pervious concrete. Orthogonal tests were employed to conduct the analysis. The findings indicate that the pervious concrete with GBFS, HPMC, and PPTF (termed GBFS-HPMC/fiber pervious concrete) exhibited the highest cubic compressive strength, ultimate tensile strength, and flexural strength. These values were 25.22 MPa, 3.36 MPa, and 5.39 MPa, respectively. The standard deviations for cubic compressive strength, split tensile strength, flexural strength, water permeability coefficient, and porosity, as calculated using SPSS, were 1.57, 0.1, 1.17, 0.35, and 0.4, respectively. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to analyze the microstructure and compositional combinations of the pervious concrete. The analyses revealed that the calcium-silicate-hydrate (C-S-H) gel, produced by GBFS hydration, enhanced the bonding within the interfacial transition zone (ITZ) and between the fibers and aggregates. Additionally, the anchoring and supporting effects of the PPTF in the matrix contributed to stabilizing the overall matrix structure. Lastly, a gray correlation analysis was applied to optimize the admixture. The findings indicate that following the optimization, the cubic compressive strength increased by 7.2%, splitting tensile strength by 2.1%, and flexural strength by 2.5%. In summary, the mechanical properties of pervious concrete improved after optimizing the admixture.

Outbreak of Vaccinia Virus Infection from Occupational Exposure, China, 2017.

Human infections with vaccinia virus (VACV), mostly from laboratory accidents or contact with infected animals, have occurred since smallpox was eradicated in 1980. No recent cases have been reported in China. We report on an outbreak of VACV from occupational exposure to rabbit skins inoculated with VACV.

Economic burden and its associated factors of hospitalized patients infected with A (H7N9) virus: a retrospective study in Eastern China, 2013-2014.

BACKGROUND: H7N9 continues to cause human infections and remains a pandemic concern. Understanding the economic impacts of this novel disease is important for making decisions on health resource allocation, including infectious disease prevention and control investment. However, there are limited data on such impacts. METHODS: Hospitalized laboratory-confirmed H7N9 patients or their families in Jiangsu Province of China were interviewed. Patients' direct medical costs of hospitalization were derived from their hospital bills. A generalized linear model was employed to estimate the mean direct medical costs of patients with different characteristics. RESULTS: The mean direct cost of hospitalization for H7N9 was estimated to be ¥ 71 060 (95 % CI, 48 180-104 820), i.e., US$ 10 996 (95 % CI, 7 455-16 220), and was ¥12 060 (US$ 1 861), ¥136 120 (US$ 21 001) and ¥218 610 (US$ 33 728) for those who had mild or severe symptoms or who died, respectively. The principal components of the total fees differed among patients with different disease severity, although medication fees were always the largest contributors. Disease severity, proportion of reimbursement and family member monthly average income were identified as the key factors that contributed to a patient's direct medical cost of hospitalization. CONCLUSIONS: The direct medical costs of hospitalized patients with H7N9 are significant, and far surpass the annual per capita income of Jiangsu Province, China. The influencing factors identified should be taken into account when developing related health insurance policies and making health resource allocation. TRIAL REGISTRATION: Not applicable. This is a survey study with no health care intervention implemented on human participants.

[Research on the aetiology of suspected enterovirus infected patients in Xuzhou district in 2009].

OBJECTIVE: To understand and master the situation in which enterovirus caused hand-foot-and-mouth disease (HFMD) in Xuzhou district in 2009 so as to provide scientific basis for the control and prevention of hand-foot-and-mouth disease. METHODS: The researchers adopted fluorescence RT-PCR method to detect EV and EV71 as well as the CA16 specificity RNA from 222 samples of anal swabs and oropharyngeal swabs from the 240 cases who were diagnosed clinically as hand-foot-mouth disease infected by enterovirus. Also, the researchers conducted EV71-IgM antibody detection on 114 samples of acute phase serum with ELA method. RESULTS: Among the 240 enterovirus infected patients, the total EV infection rate is 72.50% (174/240), among which EV71 infection rate is 57.92% (139/240), CoxA16 infection rate is 9.17% (22/240), and other EV infection rate is 5.42% (13/240). The EV71-RNA positive rate of the samples of 222 anus swabs among the 240 suspected enterovirus infected patients is 45.94% (102/222), the samples of swallow swab EV71-RNA positive rate is 25.68% (57/222) and the EV71-IgM antibody positive rate of 114 samples of acute phase serum is 86.84% (99/114). The EV71-RNA positive rate of oropharyngeal swabs of 254 healthy children is 1.57% (4/254) , and no CoxA16-RNA was detected. In the oropharyngeal swabs of 54 close contacts (medical personnel), the EV-RNA detected is negative. The positive rate of EV71-IgM antibody of the 258 healthy children's serum samples is 2.71% (7/258). CONCLUSION: The widespreading of hand-foot-mouth disease in Xuzhou district is caused mainly by type 71 enterovirus. Inapparent infection of type 71 enterovirus exists among children under the age of 3 during the time of widespreading period and IgM antibody develops in them. It is difficult for adults to be infected by EV71 even if they contact the contagion source closely. The positive rate of EV71-IgM antibody in the samples of acute phase serum of suspected cases is the highest (86.84%), and the second highest is the positive rate of RNA of EV71 of anal swabs (45.94%) and of the EV71 of oropharyngeal swabs (25.68%). ELA reagent kit is used in the early diagnosis of EV71 infection for it is easy to operate, fast and economic, so, it is worth popularizing in the grass-root medical units.