Short-term effects of high-resolution (1-km) ambient PM2.5 and PM10 on hospital admission for pulmonary tuberculosis: a case-crossover study in Hainan, China.

Introduction: There is limited evidence regarding particulate matter (PM)'s short-term effects on pulmonary tuberculosis (PTB) hospital admission. Our study aimed to determine the short-term associations of the exposure to ambient PM with aerodynamic diameters <2.5 µm (PM2.5) and < 10 µm (PM10) with hospital admission for PTB in Hainan, a tropical province in China. Methods: We collected individual data on patients hospitalized with PTB, PM2.5, PM10, and meteorological data from 2016 to 2019 in Hainan Province, China. Conditional logistic regression models with a time-stratified case-crossover design were used to assess the short-term effects of PM2.5 and PM10 on hospital admission for PTB at a spatial resolution of 1 km × 1 km. Stratified analyses were performed according to age at admission, sex, marital status, administrative division, and season of admission. Results: Each interquartile range (IQR) increases in the concentrations of PM2.5 and PM10 were associated with 1.155 (95% confidence interval [CI]: 1.041-1.282) and 1.142 (95% CI: 1.033-1.263) hospital admission risks for PTB at lag 0-8 days, respectively. The stratified analyses showed that the effects of PM2.5 and PM10 were statistically significant for patients aged ≥65 years, males, married, and those residing in prefecture-level cities. Regarding seasonal differences, the associations between PM and hospital admission for PTB were statistically significant in the warm season but not in the cold season. The effect of PM2.5 was consistently stronger than that of PM10 in most subgroups. Conclusion: Short-term exposure to PM increases the risk of hospital admission for PTB. The potential impact of PM with smaller aerodynamic diameter is more detrimental. Our findings highlight the importance of reducing ambient PM level to alleviate the burden of PTB.

Effect of electrodialysis on colloidal geometry and dynamics: Why my membrane stack was clogged even after a fine pretreatment?

As a long-standing problem, electrodialysis (ED) clogging is believed a consequence of colloids. However, its blocking causation and clogging mechanism have not been verified. In this study, electrodialysis was used to treat a colloidal saline solution, aiming to answer the question from the "nature" of ED by investigating the influence of ED parameters such as laminar flow, salt concentration, current density and pH on colloid geometry and dynamics during the desalting process. The results revealed that: (i) laminar and membrane electrostatic repulsion and adsorption could not significantly increase the particle size (maximum 2.28 times), while the applied electric field elevated the particle size by 54.52 times (119.9 ± 13.66 to 6537.5 ± 64.35 nm); (ii) when the initial feed concentration elevated 10 times (0.1 to 1 mol/L NaCl), the particle size upsurged 149-fold (5.99 ± 0.57 to >150 µm), and flocs were generated. This enhancement was mainly attributed to the compressive electric double layer effect, and the Debye length was trimmed from 0.96 to 0.30 nm; (iii) The low current density (25 A/m2) had a profound aggregation effect on small BSA particles (roughly 10 nm); (iv) The change of pH causes the conformational transition of BSA. In the strong acidic (pH = 3.0) environment, the colloidal particle size expanded by 13 times. This study confirmed that the aggregation of colloids was the culprit of spacer clogging during electrodialysis at higher salt concentrations (>1 mol/L). Furthermore, experimental data were substituted into the simulation formula to summarise the geometry and dynamic variation of BSA in ED.

Case analysis of brain abscesses caused by Nocardia asiatica: A case report / 中国热带医学

@#Abstract: Objective　To investigate the clinical characteristics and diagnosis key points of brain abscess caused by Nocardia asiatica, and provide a clinical basis for diagnosing and treating intracranial infection caused by Nocardia. Methods　A case of pulmonary Nocardia asiatica complicated with brain abscess diagnosed at the Second Affiliated Hospital of Hainan Medical University was selected to analyze the clinical manifestations, cerebrospinal fluid characteristics, pulmonary and cranial imaging features, and treatment plan, and to summarize the diagnosis and treatment experience. Results　The patient was an elderly woman with a history of diabetes, dry cough was the first symptom without fever or headache. At the beginning of the course, it was diagnosed as pulmonary infection and tuberculosis in the local hospital, and received conventional antimicrobial and anti-tuberculosis therapies, but showed no improvement. The patient developed progressive limb weakness, followed by consciousness disorders, and coma. Cerebrospinal fluid (CSF) adenosine deaminase and lactate dehydrogenase were not abnormal, CSF pressure, protein and white blood cells were high, mainly with multiple nuclear cells. CSF glucose and chloride were normal in the early stage of the disease, but decreased significantly in the later stage. Metagenomic analysis of cerebrospinal fluid indicated Nocardia asiatica with a specific sequence number of 537. Lung CT showed exudation, abscess, and cavity in the right lung. Skull MRI scan + enhancement suggested multiple scattered abscesses in both cerebral hemispheres. The abscesses were of different sizes and showed ring enhancement, with extensive surrounding edema, and ventricular compression. After treatment with meropenem, linezolid, and compound sulfamethoxazole tablets, the cerebrospinal fluid recovered, and the lesions in the lungs and intracranial structures improved. Conclusions　Brain abscess caused by Nocardia asiatica is similar to the tuberculous brain in clinical symptoms, cerebrospinal fluid examination, craniocerebral imaging, so we should be alert to the possibility of Nocardia infection in patients with diabetes. At the same time, metagenomic testing of the cerebrospinal fluid can help confirm the diagnosis. The mortality and disability rates of brain abscess caused by Nocardia are high. Early diagnosis and treatment can improve the prognosis.

Study of the association of interferon-γ gene polymorphisms and Th1/Th2 balance in tuberculosis susceptibility.

OBJECTIVES: This study investigated and analyzed the association of interferon-γ (IFN-γ) gene polymorphisms and Th1/Th2 balance in tuberculosis susceptibility. METHODS: From January 2018 to January 2020, 121 tuberculosis patients that were hospitalized for initial treatment and were chosen as the pulmonary tuberculosis group, and another 80 healthy individuals with physical examination in the same period were selected as the control group. The genetic distribution of IFN-γ +874 sites in the two sets of subjects was detected by sequence-specific primer PCR (PCR-SSP), the serum IFN-γ level was detected by ELISA, and the ratio of Th1 and Th2 on cells in two sets of subjects were detected by flow cytometry. Subsequently, we compared the differences in IFN-γ degree and the changes in Th1/Th2 in patients with different genotypes. RESULTS: The difference in the distribution of IFN-γ (+874 T/A) genotype frequencies between the two groups of subjects was significantly different (P<0.05), and the frequency of A allele in the tuberculosis group was clearly higher than that in the control group (P<0.05). Compared with the control group, the Th1 cells percentage in the pulmonary tuberculosis group decreased remarkably, the Th2 cells percentage increased significantly, while the Th1/Th2 ratio was notably decreased (P<0.05). In addition, the Th1/Th2 ratio in tuberculosis patients with an IFN-γ (+874 T/A) genotype AA was remarkably lower than those with AT+TT genotype (P<0.05). CONCLUSION: An AA genotype with IFN-γ (+874 T/A) is a susceptible genotype for tuberculosis. The mechanism may be related to the imbalance of Th1/Th2 which is more likely to occur in patients with AA genotype. This can lead to a decline in immune function of the body, making it more susceptible to infection with mycobacterium which induces tuberculosis.

Isolation of two salt-tolerant strains from activated sludge and its COD degradation characteristics from saline organic wastewater.

The efficient biological treatment of saline wastewater has been limited by the low activities of microorganisms under saline conditions. High salinity poses unbalance osmotic stress across the cell wall and even leads to cell plasmolysis. In this work, we aim to isolate salt-tolerant bacterial strains from activated sludge, and apply them for degrading chemical oxygen demand (COD) of saline organic wastewater. Two salt-tolerant strains were screened and isolated from activated sludge, which was domesticated with salty water for over 300 days. The two strains were identified as Bacillus cereus (strain A) and Bacillus anthracis (strain B) through 16S rRNA sequencing. The degradation characteristics of strain A were explored. The results showed the relative membrane permeability of strain A remained stable under high salt stress, which glycine and proline play an important role to maintain cell osmotic. The protein and soluble sugar amounts of strain were increased by higher salt concentrations. In simulating saline wastewater, the optimum culture temperature, pH, salinity, influent COD concentration and inoculation amount of strain A were 35 °C, 9, 4%, 8000 mg L-1, 6%, respectively. Optimal conditions could provide guidance for the treatment of practical saline wastewater. The linear regression model of each impact factor built based on the result PB experiment revealed that cross-linking time has the most significant influence on COD removal for salt-tolerant strains. It will provide theoretical basis for biological treatment of saline organic wastewater.

Synthesis of a novel isatin and ethylenediamine modified resin and effective adsorption behavior towards Orange G.

In this study, a novel crosslinked resin 135-I-EDA modified by isatin and ethylenediamine was synthesized through two continuous functionalization steps using chloromethylated styrene-divinylbenzene copolymer as the substrate. In the first step, the cross-linking reaction and isatin incorporation were realized in a creative one-pot reaction using Friedel-crafts reaction in the presence of isatin to give resin 135-I; in the second step, ethylenediamine was successfully introduced on the carbonyl of the modified isatin to further increase the chemically interacting sites. The double-modified resin 135-I-EDA displayed the best adsorption performance (113.38 mg g-1) towards Orange G, which is 1.99 times and 3.49 times as much as that of 135-I (56.94 mg g-1) and commercial resin H-103 (32.51 mg g-1) respectively. This is attributed to its superior porous structure formed in the Friedel-crafts reaction and multiple modified groups in isatin and ethylenediamine. π-π conjugation and hydrogen bonding are the main driving forces for the adsorption. The pseudo-second-order rate equation characterizes the adsorption kinetic curves well and 135-I-EDA displayed the fastest adsorption rate. The study also proved that the 135-I-EDA has a better adsorption capacity for OG in more acidic solution, at higher temperature and higher salinity, which provides a basis for the treatment of industrial dye wastewater.

[Influence of Salinity on Microbial Community in Activated Sludge and Its Application in Simulated Dye Wastewater Treatment].

The performance and microbial community profiles in a sequencing batch reactor(SBR) treating saline wastewater were studied over 300 days from 0% to 2.0% salinity. The effects of crystal violet wastewater and nano-ferroferric oxide on microbial communities were also researched. The experimental results indicated that the activated sludge had high sensitivity to salinity variations in terms of pollutants removal and sedimentation. At 2.0% salinity, the system retained a good performance, and 80% removal rate of COD and 75% removal rate of NH4+-N could be achieved and SVI value was less than 35 mL·g-1; With the increase of salinity, the microbial diversity reduced gradually, the advantageous position of Gram-negative bacteria was gradually replaced by fungi and actinomycetes, whereas Gram-positive bacteria strains remained the advantageous group; In the comparison of activated sludge added with crystal violet dye with the activated sludge samples with a salinity of 2%, it was found that the contents of Parvibaculum and Winogradskyella were higher while the contents of Rhodanobacter and Agrobacterium decreased. In the comparison of crystal violet-activated sludge with and without addition of MNPs, it was found that the contents of Acidocella and Rhodanobacter were higher while the contents of Parvibaculum and Agrobacterium decreased.

Innovative slow-release organic carbon-source material for groundwater in situ denitrification.

Slow-release organic carbon-source (SOC) material, a new kind of electron donor for in situ groundwater denitrification, was prepared and evaluated in this study. With starch as a biologically utilized carbon source and polyvinyl alcohol (PVA) as a frame, this material performed controllable carbon release rates and demonstrated stable behaviour during the simulated denitrification process. Raman spectrum analysis showed that the PVA skeleton formed cross-linking network structures for hydrogen-bonded water molecules reset in low temperatures, and the starchy molecules filled in the interspace of the skeleton to form a two-phase interlocking/disperse phase structure. In a static system, carbon release processes followed the Fickian law with (1.294-6.560)×10(-3) mg g(-1) s(-1/2) as the release coefficient. Under domestication and in situ groundwater simulation conditions, SOC material played a favourable role during denitrification, with 1.049±0.165 as an average carbon-nitrogen ratio. The denitrification process followed the law of zero-order kinetics, while the dynamics parameter kN was 0.563-8.753 gN m(-3) d(-1). Generally, SOC material was suggested to be a potential carbon source (electron donor) suitable for in situ groundwater denitrification.

Structure and mass transportation model of slow-release organic carbon-source material for groundwater in situ denitrification.

Based on the theories of organic polymer and chemical kinetics, the structure and mass transportation model of slow-release organic carbon-source (SOC) material was developed in this study to reveal and predict the carbon release mechanisms of polymer carbon source, which was feasible for in situ denitrification in nitrate-contaminated groundwater. Composed of polyvinyl alcohol (PVA) and starch, the SOC material formed the interlocking/disperse-phase structure. PVA performed as continuous phase and skeleton, whereas the starch or cellulose behaved as release component. Carbon release process was identified in two stages: solid-phase (inner) and interface (gel layer) diffusion. Solid-phase diffusion was affected by material porous medium parameters, for example, distance between the crosslinking points and starch free energy. The interface diffusion depended mostly on the groundwater dynamics and interface energy distribution. The interface diffusion was found as the limiting step of carbon release process, and the carbon release coefficient corresponded to kD,I as static coefficient and kC,I as dynamic coefficient. As the key indicator to evaluate carbon release capacity, kD,I and kC,I represented appropriate boundary conditions and interface properties. Sensitivity analysis showed that the key parameters of the carbon release model were the distance between the crosslinking points and the free energy of polymer, influenced by regulation of preparation technique, raw material composition and additive dosage.

[Research on treatment of high salt wastewater by the graphite and activated carbon fiber composite electrodes].

High salinity wastewater is one of the difficulties in the field of wastewater treatment. As a new desalination technology, electrosorption technology has many advantages. This paper studied a new type of carbon-based electrodes, the graphite and activated carbon fiber composite electrodes. And the influencing factors of electrosorption and its desalination effect were investigated. The electrosorption device had optimal desalination effect when the voltage was 1. 6 V, the retention time was 60 min and the plate spacing was 1 cm. The graphite and activated carbon fiber composite electrodes were used to treat the black liquor of refined cotton and sodium copper chlorophyll wastewater to investigate its desalination effect. When the electrodes were used to treat the black liquor of refined cotton after acid treatment, the removal rate of conductivity and COD reached 58. 8% and 75. 6% respectively when 8 pairs of electrodes were used. And when the electrode was used to treat the sodium copper chlorophyll wastewater, the removal rate of conductivity and COD reached higher than 50. 0% and 13. 5% respectively when 6-8 pairs of electrodes were used.

[Performance of slow-release organic carbon-source (SOC) materials for in-situ biological denitrification in groundwater].

As lack of electron donor (carbon source) is a key problem of in-situ denitrification in groundwater, slow-release organic carbon-source (SOC) materials were produced as appropriate electron donor in denitrification PRB. GPVAS and GEPVAS series were manufactured by blending starch and PVA together, with alpha-amylase as the additive, and their performance was detected through SEM and static batch experiments. The results showed that PVA formed the framework filling with starch molecule, and the carbon releasing process followed the law of second order kinetics. Equilibrium concentration of COD (c(m)) and release rate coefficient (k) were key factors of kinetics evaluation. Both c(m) and k of GPVAS-40 were the lowest. The influence of alpha-amylase to the performance of SOC materials was remarkable. The c(m) values would ascend rapidly with augmenting of alpha-amylase content, while the releasing speed rose when amylase activity was lower than 0.03 U/g and then decreased. Consequently, the releasing process was controllable through changing the content of starch and activity of alpha-amylase to meet needs of different situations and pollution of groundwater and improve the effect of in-situ nitrate removal.