Mutations and intron polymorphisms in voltage-gated sodium channel genes of different geographic populations of Culex pipiens pallens/Culex pipiens quinquefasciatus in China

BACKGROUND

Culex pipiens pallens and Culex pipiens quinquefasciatus are the dominant species of Culex mosquitoes in China and important disease vectors. Long-term use of insecticides can cause mutations in the voltage-gated sodium channel (vgsc) gene of mosquitoes, but little is known about the current status and evolutionary origins of vgsc gene in different geographic populations. Therefore, this study aimed to determine the current status of vgsc genes in Cx. p. pallens and Cx. p. quinquefasciatus in China and to investigate the evolutionary inheritance of neighboring downstream introns of the vgsc gene to determine the impact of insecticides on long-term evolution.

METHODS

Sampling was conducted from July to September 2021 in representative habitats of 22 provincial-level administrative divisions in China. Genomic DNA was extracted from 1308 mosquitoes, the IIS6 fragment of the vgsc gene on the nerve cell membrane was amplified using polymerase chain reaction, and the sequence was used to evaluate allele frequency and knockdown resistance (kdr) frequency. MEGA 11 was used to construct neighbor-joining (NJ) tree. PopART was used to build a TCS network.

RESULTS

There were 6 alleles and 6 genotypes at the L1014 locus, which included the wild-type alleles TTA/L and CTA/L and the mutant alleles TTT/F, TTC/F, TCT/S and TCA/S. The geographic populations with a kdr frequency less than 20.00% were mainly concentrated in the regions north of 38° N, and the geographic populations with a kdr frequency greater than 80.00% were concentrated in the regions south of 30° N. kdr frequency increased with decreasing latitude. And within the same latitude, the frequency of kdr in large cities is relatively high. Mutations were correlated with the number of introns. The mutant allele TCA/S has only one intron, the mutant allele TTT/F has three introns, and the wild-type allele TTA/L has 17 introns.

CONCLUSIONS

Cx. p. pallens and Cx. p. quinquefasciatus have developed resistance to insecticides in most regions of China. The neighboring downstream introns of the vgsc gene gradually decreased to one intron with the mutation of the vgsc gene. Mutations may originate from multiple mutation events rather than from a single origin, and populations lacking mutations may be genetically isolated.

Predicting the global potential distribution of two major vectors of Rocky Mountain Spotted Fever under conditions of global climate change

Rocky Mountain spotted fever is a tick-borne disease that is highly dangerous but often overlooked by the public. To prevent the spread of the disease, it is important to understand the distribution patterns of its vectors' suitable areas. This study aims to explore the potential global suitability of areas for the vectors of Rocky Mountain spotted fever, including Dermacentor variabilis and Amblyomma cajennense under both historical and future climate scenarios. The study also seeks to investigate the impact of climatic factors on the distribution patterns of these vectors. Data on species distribution were downloaded from the Global Biodiversity Information Facility, Web of Science and PubMed database. The climatic variables were downloaded from WorldClim Global Climate Database. The Maximum Entropy Model was used to evaluate the contribution of monthly precipitation, monthly maximum temperature, monthly minimum temperature, elevation, and nineteen other climatic variables to vector survival, as well as to predict the suitable area for the vectors. We found that D. variabilis is distributed in North America, while A. cajennense is mainly distributed in South America, but all other continents except Antarctica have a suitable distribution. D. variabilis is more likely to survive in temperate regions, and A. cajennense is more likely to survive in tropical zones. D. variabilis is more sensitive to temperature, whereas A. cajennense is sensitive to both temperature and precipitation, and A. cajennense prefers tropical regions with hot and humid characteristics. The high suitable areas of both vectors were almost expanded in the ssp5-8.5 scenario, but not so much in the ssp1-2.6 scenario. Highly suitable areas with vectors survival should be strengthened with additional testing to prevent related diseases from occurring, and other highly suitable areas should be alert for entry and exit monitoring to prevent invasion and colonization of vectors.

Subzero saline chilling with or without prechilling in icy water improved chilling efficiency and meat tenderness of broiler carcasses

Freshly slaughtered carcasses need to be chilled to improve product quality, meat safety, and processing efficiency. This research investigated the effect of subzero saline chilling (SSC) on broiler carcasses with or without prechilling in icy water. Water immersion chilling at 0.5°C (WIC) or SSC at 4% NaCl/-2.41°C (SSC) was a major chilling step. For the combination of pre- and postchilling, the warm water immersion chilling (WWIC) at 10°C was used as prechilling and the WIC as postchilling (WWIC-WIC), and WIC was used as prechilling and the SSC as postchilling (WIC-SSC). The internal temperature of breast fillets was monitored during chilling. Carcasses in a prechiller were transported to a postchiller when their internal temperature reached 15°C. Chilling was completed when the carcass temperature reached 4.4°C or below, and breast fillets were harvested at 3-h postmortem to measure the pH and sarcomere length. Color (L*, a*, and b*) values were evaluated on both breast skin and skinless breast surfaces. Meat tenderness was evaluated using the breast fillets after overnight storage and cooking to an internal temperature of 76°C. The carcasses in the SSC and WIC-SSC showed shorter chilling times (85-91 min) than those (100-144 min) of WIC and WWIC-WIC. A higher chilling yield was observed for the carcasses in WIC-SSC, and a lower cooking yield was seen for the carcasses in WWIC-WIC than other chilling methods (P < 0.05). The breast fillets of broilers in the SSC and WIC-SSC showed lower shear forces and longer sarcomere length than the WIC and WWIC-WIC. No difference was found for L* and a* values, while lower b* value was observed in the SSC than the other chilling methods (P < 0.05). Based on these results, chilling of broiler carcasses in the SSC (4% NaCl/-2.41°C) with or without prechilling in WIC at 0.5°C significantly improved chilling efficiency and meat tenderness, with minor color changes on carcasses.

Indirect Electrocatalysis S─N/S─S Bond Construction by Robust Polyoxometalate Based Foams

Indirect electrocatalytic conversion of cheap organic raw materials via the activation of S─H and N─H bonds into the value-added S─N/S─S bonds chemicals for industrial rubber production is a promising strategy to realize the atomic economic reaction, during which the kinetic inhibition that is associated with the electron transfer at the electrode/electrolyte interface in traditional direct electrocatalysis can be eliminated to achieve higher performance. In this work, a series of di-copper-substituted phosphotungstatebased foams (PW10 Cu2 @CMC) are fabricated with tunable loadings (17 to 44 wt%), which can be successfully applied in indirect electrocatalytic syntheses of sulfenamides and disulfides. Specifically, the optimal PW10 Cu2 @CMC (44 wt%) exhibits excellent electrocatalytic performance for the construction of S─N/S─S bonds (yields up to 99%) coupling with the efficient production of H2 (≈50 µmol g-1  h-1 ). Remarkably, it enables the scale-up production (≈14.4 g in a batch experiment) and the obtained products can serve as rubber vulcanization accelerators with superior properties to traditional industrial rubber additives in real industrial processes. This powerful catalysis system that can simultaneously produce rubber vulcanization accelerator and H2 may inaugurate a new electrocatalytic avenue to explore polyoxometalate-based foam catalysts in electrocatalysis field.

Reactivities of silane coupling agents in the silica/rubber composites: Theoretical insights into the relationships between energy barriers and electronic characteristics

Si69 and Si75, typical commodities of silane coupling agents, are often employed in tire recipes to work as the bridges connecting silica and polymers, with which rolling resistance and wet traction are enhanced without loss in abrasion resistance. In this article, the reactivities of Si69 and Si75 with silica and various rubbers were theoretically investigated by using density functional theory (DFT). When the agents were coupled with silica, not only the acid+water condition but also the pure acid condition was confirmed to readily trigger the condensation reactions. The corresponding Gibbs free energy barriers were related to the charge distributions of reaction regions. As the agents suffered from the homolysis of central SS bonds, the generated single-S-tailer radicals (RS·) showed significantly higher reactivities of both the radical addition and the α-H transfer reactions with rubbers, due to the stronger radical philicities of the terminal sulfur radicals with larger condensed local softnesses [s⁰ (S)]. When the agents underwent the heterolysis of central SS bonds, the terminal sulfur anions with smaller s^- (S) indices, however, facilitated the nucleophilic addition reactions with rubbers. Several derivative indices based on the condensed local softnesses were also proposed here to shed light on the reactivities from the viewpoint of the relationship between energy barriers and electronic characteristics. The above findings pave the way for the design of new kinds of silane coupling agents using computer-aided techniques, and meanwhile, provide references for the practical application of Si69 and Si75 to the silica/rubbers systems.

Predicting global potential distribution of Peromyscopsylla hesperomys and Orchopeas sexdentatus and risk assessment for invading China under climate change

Background

Peromyscopsylla hesperomys and Orchopeas sexdentatus are regarded to be representative plague vectors in the United States. The incidence of plague is rising globally, possibly due to climate change and environmental damage. Environmental factors such as temperature and precipitation have a significant impact on the temporal and spatial distribution of plague vectors.

Methods

Maximum entropy models (MaxEnt) were utilized to predict the distributions of these two fleas and their trends into the future. The main environmental factors influencing the distribution of these two fleas were analyzed. A risk assessment system was constructed to calculate the invasion risk values of the species.

Results

Temperature has a significant effect on the distribution of the potentially suitable areas for P. hesperomys and O. sexdentatus. They have the potential to survive in suitable areas of China in the future. The risk assessment system indicated that the risk level for the invasion of these two species into China was moderate.

Conclusion

In order to achieve early detection, early interception, and early management, China should perfect its monitoring infrastructure and develop scientific prevention and control strategies to prevent the invasion of foreign flea vectors.

[Trueness of 4 three-dimensional facial scanners: an in vitro study]

Objective: To investigate the trueness of 4 three-dimensional (3D) facial scanners and to evaluate the applicability of their clinical use. Methods: An art head model was used as the scanning object, and it was scanned by Handyscan 3D scanner in an enclosed environment with a fixed light source to obtain the reference digital model. Three fixed 3D facial scanners (A: 3dMDface; B: Facego Pro; C: RDS Facescan) and a portable hand-held 3D facial scanner (D: Revopoint POP 2) were used to scan the art head model 10 times, and 10 models of each scan group were obtained. The face of the reference model was divided into 16 regions according to anatomy and muscle distributions in the Geomagic Wrap software with saved boundary curves of whole face and each region. The test models were also divided into 16 regions through the curves above after registered with the reference model through "Best fit" function. The root-mean-square error (RMS) of the complete test models and their segmented regions compared with the reference model and its corresponding regions were calculated by 3D comparison function. The smaller the RMS, the higher the accuracy. One-way ANOVA and SNK post-test were used for statistical analysis. Results: RMS of complete test models scanned by A, B, C, D scanners were (0.295±0.005), (0.216±0.053), (0.059±0.012) and (0.103±0.026) mm (F=123.81, P<0.001), respectively. There was significant difference between any two groups (P<0.05). For each facial region, the group D had the best trueness in nasal region, lip region, left orbital region and right orbital region [RMS were (0.079±0.032), (0.061±0.019), (0.058±0.021), (0.081±0.032) mm, respectively], while the group C had the best trueness in frontal region, left buccal region, right buccal region, left zygomatic region, right zygomatic region, left parotideomasseteric region, right parotideomasseteric region, left temporofacial region, right temporofacial region, mental region, left infraorbital region and right infraorbital region [RMS were (0.039±0.011), (0.034±0.007), (0.033±0.007), (0.066±0.023), (0.038±0.022), (0.070±0.030), (0.067±0.024), (0.063±0.029), (0.045±0.023), (0.063±0.006), (0.039±0.010), (0.046±0.008) mm, respectively]. Conclusions: On the basis of art head model scanning, although the overall average deviation between the scanning model and the reference models obtained by the four kinds of 3D facial scanners were small, the portable handheld 3D facial scanner (D) has better accuracy than the fixed 3D facial scanners (A, B, C) in the orbital area, nasal area, lip area and areas with rich features.

[The opportunities and challenges of gynecologic cancer in precision medicine]

In recent years, the diagnosis and treatment of gynecologic cancer have entered a new era with the development of precision medicine. The diagnosis and treatment modes for ovarian cancer, cervical cancer, and endometrial cancer are constantly adjusted. The application of molecular targeted drugs and the progress of surgical concepts and technology have greatly improved the survival of patients with ovarian cancer. Immunotherapy and targeted therapy have become a new hot spot in the treatment of cervical cancer. More clinical research data have been accumulated on the comparison of laparoscopic and open radical hysterectomy in cervical cancer. The surgical management of endometrial cancer has been improved, and molecular diagnostics are increasingly used to guide the diagnosis and treatment of endometrial cancer. Meanwhile, it's necessary to realize the limitations and challenges of precision medicine in gynecologic cancer.

Molecular Simulation to Explore the Dissolution Behavior of Sulfur in Carbon Disulfide

Soluble sulfur (S₈) and insoluble sulfur (IS) have different application fields, and molecular dynamics simulation can reveal their differences in solubility in solvents. It is found that in the simulated carbon disulfide (CS₂) solvent, soluble sulfur in the form of clusters mainly promotes the dissolution of clusters through van der Waals interaction between solvent molecules (CS₂) and S₈, and the solubility gradually increases with the increase in temperature. However, the strong interaction between polymer chains of insoluble sulfur in the form of polymer hinders the diffusion of IS into CS₂ solvent, which is not conducive to high-temperature dissolution. The simulated solubility parameter shows that the solubility parameter of soluble sulfur is closer to that of the solvent, which is consistent with the above explanation that soluble sulfur is easy to dissolve.

Intraventricular pressure gradient: a promising tool to predict the post-infarction chronic congestive heart failure in rats

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction: Congestive heart failure (CHF), the main reason for morbidity and mortality, is considered a serious consequence of myocardial infarction (MI). The use of left ventricular end-diastolic pressure (LVEDP) as a chief indicator of CHF becomes limited because of the possible impairment of cardiac function and induced aortic valve damage during its recording. Echocardiography is the gold standard approach to diagnose structural myocardial dysfunction. However, its ability to predict chronic CHF following MI is still limited. Recently, intraventricular pressure gradient (IVPG) was presented as a non-invasive, highly sensitive preload-independent diastolic function parameter to assess cardiac function, especially during cardiomyopathy. However, there have not been any investigations demonstrating the feasibility of IVPG in the evaluation of post-infarction chronic CHF.

Purpose

This study aimed to investigate the utility of IVPG to assess the heart function in a rat model with chronic CHF following MI with evaluating its capacity to predict these changes.

Methods

Fifty male rats were included. MI was induced via ligation of the left anterior descending artery (LAD) at the level of the atrioventricular junction (MI animals, n = 35). Sham animals were subjected to the same left thoracotomy procedure without LAD ligation (Sham animals, n = 15). Transthoracic conventional echocardiography and colour M-mode echocardiography (CMME) for IVPG were performed in all animals 6 months post-surgery. The next day, animals were anesthetized, ventilated, and euthanized after the recording of hemodynamics. The heart weight, and lung and liver wet-to-dry weight ratios were recorded. J-tree cluster-analysis was performed based on ten echocardiographic variables indicative of CHF.

Results

Based on the cluster analysis, animals were joined into two clusters; CHF+ (n = 22) and named MI/HF+, and CHF- (n = 28) that was joined from sham (n = 15), and MI/HF- (n = 13). MI/HF+ presented the most severe anatomical and echocardiographic changes indicative of CHF with significant reduction of all IVPG indices and impairment of the hemodynamics. The IVPG indices were significantly (P&lt; 0.0001) correlated with the anatomical and echocardiographic findings, LVDP, LVEDP, HR, -dP/dtmin, and Tau. Meanwhile, LVSP was only significantly correlated with apical IVPG (R = 0.677, P = 0.022). dP/dtmax was significantly correlated with total IVPG, basal IVPG, and apical IVPG (R = 0.797, P = 0.017, R = 0.724, P = 0.003, and R = 0.652, P = 0.026 ; respectively). Moreover, total, basal, mid-to-apical, mid-, and apical IVPG were significant (P&lt; 0.0001) predictors of chronic CHF following MI.

Conclusion

Compared to the structural, and functional indices of conventional echocardiography, IVPG derived from CMME could provide a substantial non-invasive tool to diagnose and predict CHF after long-term MI.

Epidemiological characteristics and temporal-spatial analysis of overseas imported dengue fever cases in outbreak provinces of China, 2005–2019

Background

Overseas imported dengue fever is an important factor in local outbreaks of this disease in the mainland of China. To better prevent and control such local outbreaks, the epidemiological characteristics and temporal-spatial distribution of overseas imported dengue fever cases in provincial-level administrative divisions (PLADs) where dengue fever is outbreak in the mainland of China were explored.

Methods

Using the Chinese National Notifiable Infectious Disease Reporting Information System (CNNDS), we identified overseas imported dengue fever cases in dengue fever outbreak areas in the mainland of China from 2005 to 2019 to draw the epidemic curve and population characteristic distribution of overseas imported cases in each PLAD. Based on spatial autocorrelation analysis of ArcGIS 10.5 and temporal-spatial scanning analysis of SaTScan 9.5, we analyzed the temporal-spatial distribution of overseas imported dengue fever in dengue fever outbreak areas in the mainland of China.

Results

A total of 11,407 imported cases, mainly from Southeast Asia, were recorded from 2005 to 2019 in these 13 PLADs. Of which 62.1% were imported into Yunnan and Guangdong Provinces. Among the imported cases, there were more males than females, mainly from the 21–50 age group. The hot spots were concentrated in parts of Yunnan, Guangdong and Fujian Provinces. We found the cluster of infected areas were expanding northward.

Conclusions

Based on the analysis of overseas imported dengue cases in 13 PLADs of the mainland of China from 2005 to 2019, we obtained the epidemiological characteristics and spatial distribution of imported dengue cases. Border controls need to pay attention to key population sectors, such as 21–50 years old men and education of key populations on dengue prevention. There is a need to improve the awareness of the prevention and control of imported cases in border areas. At the same time, northern regions cannot relax their vigilance.

Graphical Abstract

Projecting the Potential Distribution Areas of Ixodes scapularis (Acari: Ixodidae) Driven by Climate Change

Ixodes scapularis is a vector of tick-borne diseases. Climate change is frequently invoked as an important cause of geographic expansions of tick-borne diseases. Environmental variables such as temperature and precipitation have an important impact on the geographical distribution of disease vectors. We used the maximum entropy model to project the potential geographic distribution and future trends of I. scapularis. The main climatic variables affecting the distribution of potential suitable areas were screened by the jackknife method. Arc Map 10.5 was used to visualize the projection results to better present the distribution of potential suitable areas. Under climate change scenarios, the potential suitable area of I. scapularis is dynamically changing. The largest suitable area of I. scapularis is under SSP3-7.0 from 2081 to 2100, while the smallest is under SSP5-8.5 from 2081 to 2100, even smaller than the current suitable area. Precipitation in May and September are the main contributing factors affecting the potential suitable areas of I. scapularis. With the opportunity to spread to more potential suitable areas, it is critical to strengthen surveillance to prevent the possible invasion of I. scapularis.

The Therapeutic Effect of Exogenous Melatonin on Depressive Symptoms: A Systematic Review and Meta-Analysis

BACKGROUND

Depression-related mortality and morbidity pose growing public health burdens worldwide. Although the therapeutic effect of exogenous melatonin on depression has been investigated, findings remain inconsistent. We conducted this systematic review and meta-analysis to clarify the effectiveness of melatonin in the treatment of depression, including primary and secondary depression symptoms.

METHODS

We searched the online databases of PubMed, EMBASE, and the Cochrane Library for original studies published up to May 2021. We used STATA 14.0 software to synthesize the results of included studies. To evaluate the effectiveness of melatonin, we calculated the standardized mean differences (SMDs) and 95% confidence intervals (CIs) of depression scores between the melatonin and placebo groups.

RESULTS

Our literature search returned 754 publications, among which 19 studies with 1,178 patients (715 women, 463 men; mean age: 56.77 years) met inclusion criteria. Melatonin dosages ranged from 2 to 25 mg per day; treatment durations were between 10 days and 3.5 years. Our synthesized results showed that melatonin was not found significantly beneficial for alleviating depressive symptoms (SMD = -0.17, 95% CI = [-0.38, 0.05]). Subgroup analysis demonstrated that the decrease in depression scores measured with the Beck Depression Inventory (BDI) was significant (SMD = -0.52, 95% CI = [-0.73, -0.31]).

CONCLUSIONS

There is very limited evidence for effects of melatonin on depression.

Male urethral diverticulum squamous cell carcinoma containing a calculus: a rare entity

Male urethral diverticula with calculi have a low incidence. It is extremely rare when the diverticulum accompanied with carcinoma. We report a case of diverticulum of the male urethra containing giant calculi which developed into squamous cell carcinoma. The patient initially presented with lower urinary tract symptoms and a hard, painless perineal mass. We believe that the process of diagnosis and treatment is of great significance in clinical practice.

[A comparative study of the retroperitoneal cavity established by the modified Hasson in urology]

Objective: To examine the safety and complications of two methods of establishing retroperitoneal cavity in urology. Methods: Totally 83 patients undergoing retroperitoneal laparoscopic surgery in Department of Urology, Shanxi Bethune Hospital from January 2020 to June 2021 were analyzed retrospectively. There were 47 males and 36 females, aged (48.3±11.3) years (range: 35 to 71 years). Forty-three cases in Hasson group(the first Trocar channel was selected at the junction of the 12^th rib and the posterior axillary line or lumbar triangle), 40 cases in modified Hasson group(the first Trocar channel is selected at 1.5 cm above the iliac crest on the mid-axillary line). The t test, χ² test, and Fisher exact test were used to compare the surgical safety indicators and complications of the two groups of patients. Results: There was no statistical difference between the two groups in gender, age, body mass index, waist length, and height (P>0.05). The comparison of safety indicators, included the time from skin incision to establishment of the retroperitoneal cavity and the amount of bleeding from the cavity were statistical difference between the two groups (P<0.05). Compared to that in Hasson group, the time from skin incision to establishment of the abdominal cavity in modified Hasson group was shorter ((8.56±2.64) minutes vs. (5.32±1.36) minutes, t=6.949, P<0.01), the blood loss of establishment was less ((15.32±6.09) ml vs. (9.85±3.55) ml, t=4.951, P<0.01). In terms of complication indicators, the incidence of Trocar hernia and the number of subcutaneous emphysema in modified Hasson group were lower than that in Hasson group (20.9% (9/43) vs. 2.5% (1/40), P=0.015, 18.6% (8/43) vs. 2.5% (1/40), P=0.030). Conclusions: The modified Hasson group is a safe method of establishing retroperitoneal cavity. The technique is simple and fast. It provides urologists with a more effective and easy-to-implement option with fewer complications.

Predicting the Potential Global Distribution of Amblyomma americanum (Acari: Ixodidae) under Near Current and Future Climatic Conditions, Using the Maximum Entropy Model

Amblyomma americanum (the lone star tick) is a pathogen vector, mainly from eastern North America, that bites humans. With global integration and climate change, some ticks that are currently confined to a certain place may begin to spread out; some reports have shown that they are undergoing rapid range expansion. The difference in the potential geographic distribution of A. americanum under current and future climatic conditions is dependent on environment variables such as temperature and precipitation, which can affect their survival. In this study, we used a maximum entropy (MaxEnt) model to predict the potential geographic distribution of A. americanum. The MaxEnt model was calibrated at the native range of A. americanum using occurrence data and the current climatic conditions. Seven WorldClim climatic variables were selected by the jackknife method and tested in MaxEnt using different combinations of model feature class functions and regularization multiplier values. The best model was chosen based on the omission rate and the lowest Akaike information criterion. The resulting model was then projected onto the global scale using the current and future climate conditions modeled under four greenhouse gas emission scenarios.

Risk Assessment of Anopheles philippinensis and Anopheles nivipes (Diptera: Culicidae) Invading China under Climate Change

BACKGROUND

Anopheles philippinensis and Anopheles nivipes are morphologically similar and are considered to be effective vectors of malaria transmission in northeastern India. Environmental factors such as temperature and rainfall have a significant impact on the temporal and spatial distribution of disease vectors driven by future climate change.

METHODS

In this study, we used the maximum entropy model to predict the potential global distribution of the two mosquito species in the near future and the trend of future distribution in China. Based on the contribution rate of environmental factors, we analyzed the main environmental factors affecting the distribution of the two mosquito species. We also constructed a disease vector risk assessment index system to calculate the comprehensive risk value of the invasive species.

RESULTS

Precipitation has a significant effect on the distribution of potentially suitable areas for Anopheles philippinensis and Anopheles nivipes. The two mosquito species may spread in the suitable areas of China in the future. The results of the risk assessment index system showed that the two mosquito species belong to the moderate invasion risk level for China.

CONCLUSIONS

China should improve the mosquito vector monitoring system, formulate scientific prevention and control strategies and strictly prevent foreign imports.

[Analysis of the clinical features and prognostic influencing factors of toxic epidermal necrolysis]

Objective: To investigate the clinical features and prognostic influencing factors of toxic epidermal necrolysis (TEN). Methods: A retrospective observational study was conducted. From January 2008 to March 2019, a total of 46 TEN patients who met the inclusion criteria were admitted to Guangdong Provincial People's Hospital. The gender, age, and hospital admission diagnosis of the 46 patients, the category of department admitted of patients complicated with sepsis, death ratio of the sepsis patients with or without treatment history in intensive care unit (ICU)/department of burns and wound repair, and the cause of death of the deceased patients were recorded. Depending on whether complicated with sepsis, the patients were divided into sepsis group (32 cases) and non-sepsis group (14 cases). According to whether died or not, the patients were divided into death group (9 cases) and survival group (37 cases). The specific conditions of suspected pathogenic agents and combined underlying diseases, the abnormality of transaminase/bilirubin, creatinine, and platelet count in blood on admission, and the detection of pathogenic microorganisms and drug resistance during the course of disease of patients were recorded in both sepsis group and non-sepsis group. The gender, age, lesion area, severity of illness score for TEN (SCORTEN) system score, combined underlying diseases on admission, and blood microbial culture positivity, hormone use, and gamma globulin use during the course of disease of patients between sepsis group and non-sepsis group, death group and survival group were compared respectively. Data were statistically analyzed with chi-square test, Fisher's exact probability test, and Mann-Whitney U test. The factors with statistically significant differences between sepsis group and non-sepsis group, death group and survival group were selected for binary multivariate logistic regression analysis, so as to screen the independent risk factors affecting sepsis and death in TEN patients. Results: Of the 46 TEN patients, 30 were male and 16 were female, aged from 8 months to 92.0 years, with 11 cases (23.91%) of epidermolysis bullosa, 9 cases (19.57%) of exfoliative dermatitis, 9 cases (19.57%) of TEN, 7 cases (15.22%) of epidermolysis bullosa, 6 cases (13.04%) of Stevens-Johnson syndrome, and 4 cases (8.70%) of severe drug rash for hospital admission diagnosis. The patients complicated with sepsis were admitted to 11 departments, and the death ratio of patients with treatment history in ICU/department of burns and wound repair was similar to that of patients without such department treatment history (P>0.05). All the deceased patients were complicated with sepsis, which was also the main cause of death. On admission, the suspected pathogenic agents of patients in sepsis group were mainly allopurinol (8 cases) and non-steroidal anti-inflammatory drugs (4 cases), while those in non-sepsis group were allopurinol (3 cases) and psychotropic drugs (3 cases). Patients in sepsis group combined as many as 10 underlying diseases, while those in non-sepsis group combined only 4 underlying diseases. The proportions of patients with increased creatinine (χ²=13.349, P<0.01) and decreased platelet count (P<0.01) in sepsis group were significantly higher than those in non-sepsis group, while the transaminase/bilirubin abnormality was similar to that in non-sepsis group (P>0.05). A wide variety of pathogens were detected in the blood, respiratory tract secretions, and skin secretions of 21 patients in sepsis group, and 14 patients were infected with drug-resistant bacteria; among the 9 strains cultured from the blood samples, 8 were drug-resistant bacteria and 6 were Gram-positive bacteria. In non-sepsis group, pathogens were detected in blood, respiratory tract secretions, and skin secretions of 8 patients, with fewer species, and 6 patients were infected with drug-resistant bacteria. The gender, age, lesion area, blood microbial culture positivity, hormone use, and gamma globulin use of patients in sepsis group were similar to those in non-sepsis group (P>0.05). The proportion of patients combined with underlying diseases (χ²=4.493, P<0.05) and the proportion of patients with SCORTEN system score of 4-6 points (P<0.01) of patients in sepsis group were significantly higher than those in non-sepsis group. The gender, combined underlying diseases, lesion area, blood microbial culture positivity, hormone use, and gamma globulin use of patients were similar between survival group and death group (P>0.05). The proportion of patients with age≥60 years and the proportion of patients with SCORTEN system score of 4-6 points of patients in death group were significantly higher than those in survival group (χ²=4.412, 11.627, P<0.05 or P<0.01). The SCORTEN system score was an independent risk factor affecting sepsis and death in TEN patients (odds ratio=3.025, 2.757, 95% confidence interval=1.352-6.769, 1.244-6.110, P<0.05 or P<0.01). Conclusions: The diagnosis of TEN is difficult on admission. Male population is susceptible to TEN, and allopurinol is the common pathogenic agent. The proportion of patients combined with underlying diseases is high in TEN patients complicated with sepsis, with mainly drug-resistant bacteria and mostly Gram-positive bacteria in blood-borne infections. The deceased patients are older than the survived, and the main cause of death is sepsis. The SCORTEN system score is an independent risk factor affecting sepsis and death in TEN patients.

[Incidence and risk factors of anastomotic leak after transanal total mesorectal excision in China: a retrospective analysis based on national database]

Objective: Transanal total mesorectal excision (taTME) was a very hot topic in the first few years since its appearance, but now more introspections and controversies on this procedure have emerged. One of the reasons why the Norwegian Ministry of Health stopped taTME was the high incidence of postoperative anastomotic leak. In current study, the incidence and risk factors of anastomotic leak after taTME were analyzed based on the data registered in the Chinese taTME Registry Collaborative (CTRC). Methods: A case-control study was carried out. Between November 15, 2017 and December 31, 2020, clinical data of 1668 patients undergoing taTME procedure registered in the CTRC database from 43 domestic centers were collected retrospectively. After excluding 98 cases without anastomosis and 109 cases without complete postoperative complication data, 1461 patients were finally enrolled for analysis. There were 1036 males (70.9%) and 425 females (29.1%) with mean age of (58.2±15.6) years and mean body mass index of (23.6±3.8) kg/m(2). Anastomotic leak was diagnosed and classified according to the International Study Group of Rectal Cancer (ISREC) criteria. The risk factors associated with postoperative anastomotic leak cases were analyzed. The impact of the cumulative number of taTME surgeries in a single center on the incidence of anastomotic leak was evaluated. As for those centers with the number of taTME surgery ≥ 40 cases, incidence of anastomic leak between 20 cases of taTME surgery in the early and later phases was compared. Results: Of 1461 patients undergoing taTME, 103(7.0%) developed anastomotic leak, including 71 (68.9%) males and 32 (31.1%) females with mean age of (59.0±13.9) years and mean body mass index of (24.5±5.7) kg/m(2). The mean distance between anastomosis site and anal verge was (2.6±1.4) cm. Thirty-nine cases (37.9%) were classified as ISREC grade A, 30 cases (29.1%) as grade B and 34 cases (33.0%) as grade C. Anastomotic leak occurred in 89 cases (7.0%,89/1263) in the laparoscopic taTME group and 14 cases (7.1%, 14/198) in the pure taTME group. Multivariate analysis showed that hand-sewn anastomosis (P=0.004) and the absence of defunctioning stoma (P=0.013) were independently associated with anastomotic leak after taTME. In the 16 centers (37.2%) which performed ≥ 30 taTME surgeries with cumulative number of 1317 taTME surgeries, 86 cases developed anastomotic leak (6.5%, 86/1317). And in the 27 centers which performed less than 30 taTME surgeries with cumulative number of 144 taTME surgeries, 17 cases developed anastomotic leak (11.8%, 17/144). There was significant difference between two kinds of center (χ(2)=5.513, P=0.019). Thirteen centers performed ≥ 40 taTME surgeries. In the early phase (the first 20 cases in each center), 29 cases (11.2%, 29/260) developed anastomotic leak, and in the later phase, 12 cases (4.6%, 12/260) developed anastomotic leak. The difference between the early phase and the later phase was statistically significant (χ(2)=7.652, P=0.006). Conclusion: The incidence of anastomotic leak after taTME may be reduced by using stapler and defunctioning stoma, or by accumulating experience.

Role of diesel exhaust particles in the induction of allergic asthma to low doses of soybean

INTRODUCTION

Exposure to environmental pollutants such as diesel exhaust particles (DEP) increases the risk of asthma and asthma exacerbation. However, the exact mechanisms inducing asthma to low doses of allergens remain poorly understood. The present study aimed to analyse the immunomodulatory effect of the inhalation of DEP in a mouse model exposed to non-asthmagenic doses of soybean hull extract (SHE).

MATERIAL AND METHODS

BALB/c ByJ mice were randomly divided into four experimental groups. Two groups received nasal instillations of saline and the other two groups received 3 mg ml-1 SHE during 5 days per week for 3 weeks. One group in each pair also received 150 μg of DEP in the same instillations 3 days per week. SHE-specific IgE levels, oxidative stress, leukocyte pattern and optical projection tomography (OPT) imaging studies were assessed.

RESULTS

Inhalation of SHE and/or DEP increased levels of H2O2 in BAL, while coexposure to SHE and DEP increased SHE-specific IgE levels in serum. Inhalation of SHE alone increased eosinophils, B cells, total and resident monocytes and decreased levels of NK cells, while inhalation of DEP increased neutrophils and decreased total monocytes. Regarding dendritic cells (DC), the inhalation of SHE and/or DEP increased the total population, while the inhalation of SHE alone increased Th2-related DCs (CD11b + Ly6C-) and decreased tolerogenic DCs (CD11b-Ly6C-). However, coexposure to SHE and DEP increased oxidative stress-sensitive DCs (CD11b-Ly6C+) and decreased Th1-related DCs (CD11b + Ly6C+). As regards macrophages, inhalation of SHE and DEP decreased total and alveolar populations. DEP deposition in lung tissue did not differ between groups.

CONCLUSION

Coexposure to DEP activates the asthmatic response to low doses of soy by triggering the immune response and oxidative stress.

Twenty-year changes in mortality rates and underlying causes of death in patients with rheumatoid arthritis-associated interstitial lung disease

Objectives: Despite recent advances in the treatment of rheumatoid arthritis (RA), few population-based studies have assessed the mortality rates and the underlying causes of death (UCDs) among patients with RA and RA-associated interstitial lung disease (RA-ILD). This study evaluated the trends in mortality rates, demographic characteristics, and UCDs among patients with RA-ILD.Method: Using data from death certificates (1999-2018) from the US Centers for Disease Control and Prevention Multiple Cause of Death files, we explored the trends in mortality rates and UCD for patients with RA and RA-ILD. Moreover, we examined the crude and age-standardized mortality rates (ASMRs) for such patients.Results: Among patients with RA or RA-ILD, ASMR variation decreased over 20 years. The ASMR ratio of RA-ILD to RA decreased by 5.84%. The ASMR for RA and RA-ILD stratified by gender or age group also decreased. The change in the ASMR ratio of RA-ILD to RA trended downwards in women and upwards in men. Arthropathies and ILD were the most frequent UCDs for RA-ILD, while arthropathies and ischaemic heart disease were the most frequent UCDs for RA.Conclusions: Although RA and RA-ILD presented a downward trend in mortality, RA combined with ILD may reduce life expectancy. Specifically, the mortality rate for patients with RA-ILD remained relatively stable during the study period when ILD was the UCD, suggesting the need for active prevention, early diagnosis, and effective management of RA-ILD.

Shear stress-induced MMP1 and PDE2A expressions in coronary atherosclerosis

AIM

Biomechanical stress plays an essential role in coronary atherosclerosis (CAS), however, inter-relations between mechanical conditions and gene expressions remain unclear.

METHODS

We constructed finite element model of CAS to map human wall shear stress (WSS). Biopsy aortic tissue samples were obtained from 3 CAS patients. Gene expression pattern in CAS was analyzed by GEO datasets. Immunofluorescence staining and western blot confirmed protein expression and localization.

RESULTS

Peak WSS was significantly increased in the vessel stenosis of CAS at 0.25 s (mean 55.1 Pa). Analyses results of GSE76275 showed matrix metalloproteinases1 (MMP1) and phosphodiesterase-2A (PDE2A) up-regulation in endothelial shear responsiveness, which was further validated and localized in vascular endothelial cells, smooth muscle cells and other cells by double immunofluorescence staining. Western blotting assay demonstrated up-regulation of MMP1 and PDE2A expression dependent on the WSS.

CONCLUSIONS

MMP1 and PDE2A up-regulations rely on increased WSS in development and risk of CAS, suggesting that their elevation may be potential target for diagnosis and treatment (Fig. 3, Ref. 28).

In Situ Electrochemical Fabrication of Ultrasmall Ru-Based Nanoparticles for Robust N2H4 Oxidation

Ultrasmall Ru nanoparticles is expected as a potential alternative to Pt for efficient hydrazine oxidation (HzOR). However, preparation of ultrasmall and well-distributed Ru nanoparticles usually suffered from the steps of modification of supports, coordination, reduction with strong reducing reagents (e.g., NaBH₄) or pyrolysis, imposing the complexity. Based on the self-reducibility of C-OH group and physical adsorption ability of commercial Ketjen black (KB), we developed an efficient, stable and robust Ru-based electrocatalyst (A-Ru-KB) by coupling impregnation of KB in RuCl₃ solution and simple in situ electrochemical activation strategy, which endowed the formation of ultrasmall and well-distributed Ru nanoparticles. Benefiting from an enhanced exposure of Ru sites and the faster mass transport, A-Ru-KB achieved 63.4 and 3.9-fold enhancements of mass activity compared with Pt/C and Ru/C, respectively, accompanied by a ∼144 mV lower onset potential and faster catalytic kinetics than Pt/C. In the hydrazine fuel cell, the open-circuit voltage and maximal mass power density of A-Ru-KB was 130 mV and ∼3.8-fold higher than those of Pt/C, respectively, together with the long-term stability. This work would provide a facile and sustainable approach for large-scale production of other robust metal (electro)catalysts with ultrasmall nanosize for various energy conversion and electrochemical organic synthesis.

The Prevalence and Control of Type 2 Diabetes Mellitus in Residents of a Rural Town, Shandong Province, China

OBJECTIVE

To understand the prevalence and control of type 2 diabetes mellitus (T2DM) in a rural area, a cross-sectional study was carried out.

METHODS

Blood glucose was determined in residents over 60 years during the National Basic Public Health Service project carrying on in a rural town of Shandong province. Combined with detail information of diabetic history, the prevalence rate of this disease was calculated with a cutoff of more than 7.0 mmol/L of fasting plasma glucose (FPG). Furthermore, according to FPG levels, the control rate of diabetes was evaluated. Basic information and clinical laboratory tests were analyzed with proper methods for univariate analysis. Multivariable logistic analysis was used to explore multiple variables associated with the control effect of T2DM.

RESULTS

The prevalence rate of T2DM was 13.5% (95% CI 12.4%~14.7%) without age difference in residents over 60-year old (X ²= 1.078, P = 0.898). And the rate was higher in the female (16.1%, 95% CI 14.4%~17.8%) than that in the male (11.3%, 95% CI 9.7%~12.9%). The control rate of diabetes was 44.5% (95% CI 39.4-49.6%, cutoff <6.1 mmol/L for FPG) and 59.6% (95% CI 54.5-64.6%, cutoff <7.0 mmol/L for FPG), respectively. Most T2DM residents had balance foods, and a high proportion of drugs or insulin were used; however, the proportion of keeping exercise and modifying behaviors was low. Nearly 80% of the diabetic individuals used at least one drug or insulin. However, the more drugs or insulin used, the higher the FPG level was.

CONCLUSION

A relative high level of T2DM prevailed in the rural area under fast economy-transforming. T2DM was controlled poor and measures should be further optimized to achieve ideal effect, especially for the use of anti-diabetic drugs.

Boosting Oxygen Electroreduction over Strained Silver

Manipulating the strain effect of Ag without any foreign metals to boost its intrinsic oxygen reduction reaction (ORR) activity is intriguing, but it remains a challenge. Herein, we developed a class of Ag-based electrocatalysts with tunable strain structures for efficient ORR via ligand-assisted competitive decomposition of Ag-organic complexes (AgOCs). Benefiting from the superior coordination capability, 4,4'-bipyridine as a ligand triggered a stronger competition with NaBH₄ for Ag ions during reduction-induced decomposition of AgOCs in comparison with the counterparts of the pyrazine ligand and the NO₃^- anion, which moderately modulated the compressive strain structure to upshift the d-band center of the catalyst and increase the electron density of Ag. Accordingly, the O₂ adsorption was obviously improved, and the stronger repulsion effect between the Ag sites and the 4e ORR product, i.e., the electron-rich OH^-, was generated to promote the desorption of OH^- via the Ag-OH bond cleavage, which enabled more Ag sites to be regenerated after ORR. Both of these led to an enhancement to the intrinsic ORR activity of the Ag-based catalyst. This competitive decomposition of metal-organic complex strategy would provide a facile method to design other catalysts with the well-tuned strain structures for energy conversion and heterocatalysis.

Effects of ET-1 and TNF-α levels on the cardiac function and prognosis in rats with chronic heart failure

OBJECTIVE

To investigate the effects of ET-1 and TNF-α levels on cardiac function and prognosis in rats with chronic heart failure (CHF), to provide reference for clinical practice.

MATERIALS AND METHODS

120 SD rats were randomly divided into healthy group (n=60) and heart failure group (n=60). Rats from heart failure group were made into CHF models by an intraperitoneal injection of adriamycin. According to the average serum levels of ET-1 and TNF-α, 30 rats with higher level were enrolled in high expression subgroup, while 30 rats with lower level were enrolled in low expression subgroup. The sandwich enzyme-linked immunosorbent assay (ELISA) was employed to determine the ET-1 and TNF-α in rats from healthy group and heart failure group. Doppler echocardiography was used to measure the left ventricular ejection fraction, heart rate, and aortic diameter. After the death of heart failure rats, the total heart mass and left ventricle mass were measured and compared with those of the healthy rats. The serum levels of ET-1 and TNF-α were monitored to explore the influence of ET-1 and TNF-α levels on the prognosis of rats from study group.

RESULTS

The total heart mass and left ventricle mass of the heart failure group were higher than those of healthy group (p<0.05). The total heart mass and left ventricle mass of the low expression subgroup were lower than those of high expression subgroup (p<0.05).

CONCLUSIONS

The serum levels of ET-1 and TNF-α are higher than those in healthy rats. CHF rats with higher serum levels of ET-1 and TNF-α have a worse heart function and survival. Serum levels of ET-1 and TNF-α can be used as predictors of cardiac function and prognosis in CHF rats, providing references for clinical practice.

Microtubule organization defects in Arabidopsis thaliana

Microtubules (MT) are critical cytoskeletal filaments that have several functions in cell morphogenesis, cell division, vesicle transport and cytoplasmic separation in the spatiotemporal regulation of eukaryotic cells. Formation of MT requires the co-interaction of MT nucleation and α-β-tubulins, as well as MT-associated proteins (MAP). Many key MAP contributing to MT nucleation and elongation are essential for MT nucleation and regulation of MT dynamics, and are conserved in the plant kingdom. Therefore, the deletion or decrease of γ-tubulin ring complex (γTuRC) components and related MAP, such as the augmin complex, NEDD1, MZT1, EB1, MAP65, etc., in Arabidopsis thaliana results in MT organizational defects in the spindle and phragmoplast MT, as well as in chromosome defects. In addition, similar defects in MT organization and chromosome structure have been observed in plants under abiotic stress conditions, such as under high UV-B radiation. The MT can sense the signal from UV-B radiation, resulting in abnormal MT arrangement. Further studies are required to determine whether the abnormal chromosomes induced by UV-B radiation can be attributed to the involvement of abnormal MT arrays in chromosome migration after DNA damage.

One Case of Soil and Groundwater Environmental Forensics Caused by Illegal Landfill Waste

Abstract

Grape-seed polyphenols inhibit AAA in mice via regulation of macrophage polarization

AIM

Abdominal aortic aneurysm (AAA) is characterized by macrophage polarization, and at present, no drug therapy is available. Although grape-seed polyphenols (GSP) showed an anti-AAA effect, the role of GSP in the phenotype shift in macrophages remains unknown.

METHOD

The main phenolic compounds in GSP were determined by LC-MS. Male C57BL/6 mice were divided into four equal groups, namely sham group, CaPO4 group, CaPO4+GSP low-dose group, and CaPO4+GSP high-dose group. GSP was administered intragastrically after CaPO4 application. Molecular expressions were histologically evaluated and analyzed by various staining assays and FACS.

RESULTS

GSP administration inhibited CaPO4-induced AAA formation, which correlated with a decrease in macrophage infiltration and retainment of vascular smooth muscle layer as compared to those in the CaPO4 group. FACS assay showed that the GSP administration dose-dependently decreased the CD54 expression (low-dose group: 11.4 ± 2.1 % and high-dose group: 4.8 ± 1.4 % vs 23.2 ± 3.6 %; p < 0.05 and p < 0.01, respectively) and increased the CD206 expression of F4/80-positive cells in GSP-administered groups as compared with that in CaPO4-injured aortas in the CaPO4 group (low-dose group: 22.4 ± 3.3 % and high-dose group: 26.7 ± 4.2 % vs 8.1 ± 1.3 %; p < 0.05 and p < 0.01, respectively).

CONCLUSIONS

GSP could be a pharmacologically potent agent in the treatment of AAA (Tab. 1, Fig. 3,Ref. 20). Text in PDF www.elis.sk Keywords: grape-seed polyphenols, abdominal aortic aneurysm, macrophage, inflammatory, polarization.

Immunorelated gene polymorphisms associated with acute myeloid leukemia

Although the pathogenesis of acute myeloid leukemia (AML) is still unknown, accumulating evidence has revealed that immune response plays a vital part in the pathogenesis. Here, we investigated the involvement of 21 single nucleotide polymorphisms (SNPs) of immunorelated genes, including cytokines [interleukin (IL)-2, IL-4, IL-9, IL-12A, IL-22, interferon (IFN-α) and transforming growth factor (TGF)-β1], transcriptional regulatory genes (TBX21, STAT1, STAT3, STAT5B, STAT6, GATA3, FOXP3 and IRF4) and others (IL2RA, IL6R, NFKBIA) in 269 AML in-patients and 200 healthy controls. Furthermore, we analyzed the relationship between the SNPs and clinical characteristics. Immunorelated SNP genotyping was performed on the Sequenom MassARRAY iPLEX platform. All the SNPs in healthy controls were consistent with Hardy-Weinberg equilibrium. All final P-values were adjusted by Bonferroni multiple testing. Our results showed that IL-22 (rs2227491) was significantly associated with the white blood cell (WBC) counts. Signal transducer and activator of transcription 5B (STAT-5B) (rs6503691) showed a close relationship with the recurrent genetic abnormalities in patients with AML. We verified the negatively independent effect of age and risk of cytogenetics on overall survival (OS). More importantly, the GG genotype of IL-12A (rs6887695) showed a negative impact on AML prognosis independently. Furthermore, the relative expression of IL-12 was decreased in GG genotype, no matter under a co-dominant or recessive model. However, no correlation was observed between the SNPs mentioned above and disease susceptibility, risk stratification and survival. Our findings suggest that immunorelated gene polymorphisms are associated with prognosis in AML, which may perform as novel inspection targets for AML patients.

Mimicking Hydrazine Dehydrogenase for Efficient Electrocatalytic Oxidation of N2H4 by Fe-NC

Pursuing nonprecious doped carbon with Pt-like electrocatalytic N₂H₄ oxidation activity for hydrazine fuel cells (HzFCs) remains a challenge. Herein, we present a Fe/N-doped carbon (Fe-NC) catalyst with mesopore-rich channel and highly dispersed Fe-N sites incorporated in N-doped carbon, as an analogue of hydrazine dehydrogenase (HDH), showing the structure-dependent activity for electrocatalytic oxidation of N₂H₄. The maximal turnover frequency of the N₂H₄ oxidation reaction (HzOR) over the Fe-N sites (62870 h^-1) is 149-fold that over the pyridinic-N sites of N-doped carbon. The Fe mass activity of HzOR and maximal power density of HzFCs driven by Fe-NC approximately surpass those of Pt/C by 2.3 and 2.2 times, respectively. Theoretical calculation reveals that the Fe-N sites improve the dehydrogenation process of HzOR-related intermediates. One of the roles of the mesoporous structure in Fe-NC resembles that of a substrate channel in HDH for enhancing the transport of N₂H₄ besides exposing Fe-N sites and improving storage capacity of HzOR-related species.

Formation and Development of Environmental Forensics System in China

With the growing attention on ecological environment problems and gradual realization of ecological environment value, environmental damage has jumped from administrative penalty to a new stage, judicial penalty, and environmental damage appraisal has provided a legal weapon to safeguard ecological security. As a new forensic category of China with high comprehensiveness and technical difficulty, environmental damage appraisal involves diversified and complex subjects, fields and appraisal objects, and is still in an early stage in terms of theory and practice. This study aims to provide an important reference for the improvement of the Chinese environmental damage appraisal system of environmental damage by summarizing advanced international experience in areas such as laws and regulations, working mechanism and technical system, and putting forward targeted countermeasures and suggestions based on the problems existing in the development and practice of environmental damage appraisal in China.

Synergetic effects of defects and acid sites of 2D-ZnO photocatalysts on the photocatalytic performance

Regulation of defects and surface acidic sites of photocatalysts is an efficient approach to improve the photocatalytic activity. Ultrathin 2D-ZnO photocatalysts were prepared to uncover the synergetic effects of defects and surface acidic sites on the photocatalytic activity. The reaction constant for photocatalytic degradation of MB upon ZnO-S is 2.26, 2.82, 12.2 times higher than that of SH-500, SO-500, and ZnO-R, respectively. The results revealed that the surface defects, hydroxyl group and chemisorbed water played pivotal roles in the generation of reactive oxygen species (ROS). Although the limited improvement of visible absorption was achieved after introduction of oxygen vacancy (V_O), the overall photocatalytic activity decreased due to the reduced ROS production capacity shown by density functional theory (DFT) calculations. Hydroxyl radical is the key ROS in degradation of organics, and electron contributes a little bigger than hole in the generation of hydroxyl radical. Importantly, the decrease in surface acidic sites resulted in the decreased photocatalytic activity, proven by the dynamics of photoinduced carriers. This study reveals that the improved photocatalytic activity of 2D-ZnO photocatalysts can be attributed to the synergetic effects of surface defects and acidic sites rather than the enhanced visible absorption resulted from the V_O introduction.