Causes and global, regional, and national burdens of traumatic brain injury from 1990 to 2019.

PURPOSE: Traumatic brain injury (TBI), currently a major global public health problem, imposes a significant economic burden on society and families. We aimed to quantify and predict the incidence and severity of TBI by analyzing its incidence, prevalence, and years lived with disability (YLDs). The epidemiological changes in TBI from 1990 to 2019 were described and updated to provide a reference for developing prevention, treatment, and incidence-reducing measures for TBI. METHODS: A secondary analysis was performed on the incidence, prevalence, and YLDs of TBI by sex, age group, and region (n = 21,204 countries and territories) between 1990 and 2019 using the Global Burden of Diseases, Injuries, and Risk Factors Study 2019. Proportions in the age-standardized incidence rate due to underlying causes of TBI and proportions of minor and moderate or severe TBI were also reported. RESULTS: In 2019, there were 27.16 million (95% uncertainty intervals (UI): 23.36 - 31.42) new cases of TBI worldwide, with age-standardized incidence and prevalence rates of 346 per 100,000 population (95% UI: 298-401) and 599 per 100,000 population (95% UI: 573-627), respectively. From 1990 to 2019, there were no significant trends in global age-standardized incidence (estimated annual percentage changes: -0.11%, 95% UI: -0.18% - -0.04%) or prevalence (estimated annual percentage changes: 0.01%, 95% UI: -0.04% - 0.06%). TBI caused 7.08 million (95% UI: 5.00 - 9.59) YLDs in 2019, with age-standardized rates of 86.5 per 100,000 population (95% UI: 61.1 - 117.2). In 2019, the countries with higher incidence rates were mainly distributed in Central Europe, Eastern Europe, and Australia. The 2019 global age-standardized incidence rate was higher in males than in females. The 2019 global incidence of moderate and severe TBI was 182.7 per 100,000 population, accounting for 52.8% of all TBI, with falls and road traffic injuries being the main causes in most regions. CONCLUSIONS: The incidence of moderate and severe TBI was slightly higher in 2019, and TBI still accounts for a significant portion of the global injury burden. The likelihood of moderate to severe TBI and the trend of major injury under each injury cause from 1990 to 2019 and the characteristics of injury mechanisms in each age group are presented, providing a basis for further research on injury causes in each age group and the future establishment of corresponding policies and protective measures.

Road traffic mortality in Zunyi city, China: A 10 - year data analysis (2013-2022).

PURPOSE: The study aimed to examine the pattern of motorization and the mortality rate related to road traffic crashes in Zunyi (a city in northern Guizhou province of China) from 2013 to 2022, and to identify the epidemiological characteristics of these crashes with to provide insights that could help improve road safety. METHODS: Data were obtained from the Zunyi traffic management data platform, and the mortality rates were calculated. We deployed various analytical methods, including descriptive analysis, Chi-square test or Fisher's exact test of categorical variable, circular distribution map analysis, and Rayleigh test to characterize the traits of road traffic crashes in the region. RESULTS: During the 10-year study period, 7488 people died due to road traffic accidents, with males accounting for 70.4% and females 29.6% (χ2 = 101.97, p < 0.001). The mortality rate increased from 7.80 deaths per 100,000 people in 2013 to 10.70 deaths per 100,000 people in 2016, but then decreased to 9.54 deaths per 100,000 people in 2019. A notable finding was that the death rate per 10,000 vehicles declined from 16.09 deaths per 10,000 vehicles in 2013 to 5.48 deaths per 10,000 vehicles in 2022. The study also found that vulnerable road users represented nearly half (48.76%) of all accident fatalities, and unlicensed or inexperienced driving contributed significantly to the occurrence of road traffic accidents. CONCLUSION: Although the number of road traffic accidents in Zunyi has decreased, there are still some critical issues that need to be addressed, particularly for vulnerable road users and unlicensed drivers. Our results highlight the need of targeted interventions to address the specific risk factors of road traffic crashes, particularly those affecting vulnerable road users and drivers without sufficient experience or license.

Gene delivery to breast cancer by incorporated EpCAM targeted DARPins into AAV2.

OBJECTIVE: The aim of this study is to evaluate an AAV vector that can selectively target breast cancer cells and to investigate its specificity and anti-tumor effects on breast cancer cells both in vitro and in vivo, offering a new therapeutic approach for the treatment of EpCAM-positive breast cancer. METHODS: In this study, a modified AAV2 viral vector was used, in which EpCAM-specific DARPin EC1 was fused to the VP2 protein of AAV2, creating a viral vector that can target breast cancer cells. The targeting ability and anti-tumor effects of this viral vector were evaluated through in vitro and in vivo experiments. RESULTS: The experimental results showed that the AAV2MEC1 virus could specifically infect EpCAM-positive breast cancer cells and accurately deliver the suicide gene HSV-TK to tumor tissue in mice, significantly inhibiting tumor growth. Compared to the traditional AAV2 viral vector, the AAV2MEC1 virus exhibited reduced accumulation in liver tissue and had no impact on tumor growth. CONCLUSION: This study demonstrates that AAV2MEC1 is a gene delivery vector capable of targeting breast cancer cells and achieving selective targeting in mice. The findings offer a potential gene delivery system and strategies for gene therapy targeting EpCAM-positive breast cancer and other tumor types.

Clear Cell Renal Cell Carcinoma Metastatic to the Mandible: a Unique Case Report and Literature Review.

Renal cell carcinoma (RCC) is often diagnosed in advanced stages and a third of patients have distant metastasis at diagnosis. Metastasis may be the first evidence of clear cell RCC in many cases. RCC most often metastasises to the lung, liver, bone, brain and thyroid; however, metastatic disease to the oral cavity, especially the mandible, is rare. The purpose of this study is to report a case of clear cell RCC metastatic to the mandible and review the literature. The mandible lesion underwent radical excision in this case. Notably, no metastatic lesions were detected in the lungs and liver in this patient until 15 months after the mandibulectomy. The patient lived for around 2.5 years after the diagnosis of RCC.

YWHAZ variation causes intellectual disability and global developmental delay with brain malformation.

YWHAZ encodes an adapter protein 14-3-3ζ, which is involved in many signaling pathways that control cellular proliferation, migration and differentiation. It has not been definitely correlated to any phenotype in OMIM. To investigate the role of YWHAZ gene in intellectual disability and global developmental delay, we conducted whole-exon sequencing in all of the available members from a large three-generation family and we discovered that a novel variant of the YWHAZ gene was associated with intellectual disability and global developmental delay. This variant is a missense mutation of YWHAZ, p.Lys49Asn/c.147A > T, which was found in all affected members but not found in other unaffected members. We also conducted computational modeling and knockdown/knockin with Drosophila to confirm the role of the YWHAZ variant in intellectual disability. Computational modeling showed that the binding energy was increased in the mutated protein combining with the ligand indicating that the c147A > T variation was a loss-of-function variant. Cognitive defects and mushroom body morphological abnormalities were observed in YWHAZ c.147A > T knockin flies. The YWHAZ knockdown flies also manifested serious cognitive defects with hyperactivity behaviors, which is consistent with the clinical features. Our clinical and experimental results consistently suggested that YWHAZ was a novel intellectual disability pathogenic gene.

The potential role of circulating exosomes in protecting myocardial injury in acute myocardial infarction via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

Exosomes of different origins have been found to be protective against ischemic-induced myocardial injury. This study examined the protective effects of circulating exosomes in the mice model of acute myocardial infarction (AMI) and explored the underlying molecular mechanisms. The effects of exosomes on myocardial injury were assessed in the AMI mice model. The in vivo studies showed that circulating exosomes reduced the infarcted size, improved the morphology of heart tissues and also reduced apoptosis of the heart tissues. In addition, the model mice showed an increase in the CD34 + /VEGFR2 + cell population and CD31, CXCR4 and CXCL12 expression after exosomes treatment. MiR-190a-3p was significantly down-regulated in the exosomes derived from the culture medium of hypoxia-treated human cardiomyocytes (HCMs). Further analysis revealed that miR-190a-3p could physically interact with CXCR4/CXCL12 by targeting the respective 3'UTRs. These exosomes could up-regulated CXCR4 and CXCL12 expression in the EPCs; in addition, miR-190a-3p mimics repressed CXCR4/CXCL12 expression in EPCs, while its inhibitor had opposite effects. The in vitro functional assays showed that miR-190a-3p overexpression suppressed the cell viability, proliferation, migration, adhesion and tube formation of EPCs; while miR-190a-3p inhibitor had the opposite effects; exosomes derived from the culture medium of hypoxia-treated HCMs exhibited similar actions of miR-190a-3p inhibitor. Moreover, miR-190a-3p was down-regulated in exosomes from serum in the AMI group when compared to that from sham group. Treatment with exosomes from serum in the AMI group promoted cell proliferation, migration, adhesion and tube formation of EPCs when compared to that in the sham group. More importantly, IT1t attenuated the enhanced effects of miR-190a-3p inhibition on EPC proliferation, migration, adhesion and tube formation. In conclusion, circulating exosomes exerted protective effects on myocardial injury in the AMI mice model, and down-regulation of miR-190a-3p in the circulating exosomes may exert protective effects against myocardial injury. Hypoxia induced the downregulation of miR-190a-3p in the culture medium of HCMs, and the mechanistic investigations indicated that exosomes of hypoxia-conditioned HCM culture medium promoted the cell viability, proliferation, migration, adhesion and tube formation of EPCs via regulating miR-190a-3p/CXCR4/CXCL12 pathway.

Catalpol counteracts the pathology in a mouse model of Duchenne muscular dystrophy by inhibiting the TGF-ß1/TAK1 signaling pathway.

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by a mutation in the gene encoding the dystrophin protein. Catalpol is an iridoid glycoside found in Chinese herbs with anti-inflammatory, anti-oxidant, anti-apoptotic, and hypoglycemic activities that can protect against muscle wasting. In the present study we investigated the effects of catalpol on DMD. Aged Dystrophin-deficient (mdx) mice (12 months old) were treated with catalpol (100, 200 mg·kg-1·d-1, ig) for 6 weeks. At the end of the experiment, the mice were sacrificed, and gastrocnemius (GAS), tibialis anterior (TA), extensor digitorum longus (EDL), soleus (SOL) muscles were collected. We found that catalpol administration dose-dependently increased stride length and decreased stride width in Gait test. Wire grip test showed that the time of wire grip and grip strength were increased. We found that catalpol administration dose-dependently alleviated skeletal muscle damage, evidenced by reduced plasma CK and LDH activity as well as increased the weight of skeletal muscles. Catalpol administration had no effect on dystrophin expression, but exerted anti-inflammatory effects. Furthermore, catalpol administration dose-dependently decreased tibialis anterior (TA) muscle fibrosis, and inhibited the expression of TGF-ß1, TAK1 and α-SMA. In primary myoblasts from mdx mice, knockdown of TAK1 abolished the inhibitory effects of catalpol on the expression levels of TGF-ß1 and α-SMA. In conclusion, catalpol can restore skeletal muscle strength and alleviate skeletal muscle damage in aged mdx mice, thus may provide a novel therapy for DMD. Catalpol attenuates muscle fibrosis by inhibiting the TGF-ß1/TAK1 signaling pathway.

Influence of road types on road traffic accidents in northern Guizhou Province, China.

PURPOSE: The increasing number of deaths due to road traffic accidents (RTAs) has attracted global attention. However, the influence of road types is rarely considered in the study of RTAs. This study evaluates the influence of different road types in RTAs in northern Guizhou to provide a basis for the formulation of evidence-based policies and measures. METHODS: We obtained the data from the Zunyi Traffic Management Data Platform for the years 2009-2018. The mortality rates of RTAs were calculated. Descriptive methods and Chi-square tests were used to analyze the characteristics of road traffic collisions on different road types. We also examined the associations between the mortality rate per 10,000 vehicles and the growth of per capital gross domestic product (GDP) with Spearman's rank correlation analysis. According to the passing volume and the infrastructure, we defined different types of roads, like administrative road, functional road, general urban road and urban expressway. RESULTS: In 2012, the traffic mortality rate of administrative roads was 8.9 per 100,000 people, and the mortality rate of functional roads was 7.4 per 100,000 people, which decreased in 2018 to 6.1 deaths per 100,000 people and 5.2 deaths per 100,000 people, respectively. The mortality rate per 10,000 vehicles reached the highest level in 2011 (28.8 per 10,000 vehicles and 22.5 per 10,000 vehicles on administrative and functional roads, respectively). The death rate of county roads was the highest among administrative roads (χ2 = 17.389, p < 0.05) and that of fourth-class roads was the highest among functional roads (χ2 = 21.785, p < 0.05). The mortality rate per 10,000 vehicles was negatively correlated with per capital GDP. CONCLUSION: Although our research shows that RTAs in northern Guizhou have steadily declined in recent years, the range of decline is relatively small. Many measures and sustainable efforts are needed to control road traffic death and accelerate the progress in road traffic safety in northern Guizhou.

Extracellular signal-regulated kinase, substance P and neurokinin-1 are involved in the analgesic mechanism of herb-partitioned moxibustion.

Herb-partitioned moxibustion can effectively mitigate visceral pain, a major symptom in inflammatory bowel disease, but the analgesic mechanism is still unclear. Moreover, extracellular signal-regulated kinase, substance P, and neurokinin-1 are involved in formation of central hyperalgesia. Thus, we postulated that the analgesic effect of herb-partitioned moxibustion may be associated with these factors. Accordingly, in this study, we established an inflammatory bowel disease visceral pain model in rat by enema with a mixed solution of 5% trinitrobenzenesulfonic acid and 50% ethanol. Bilateral Tianshu (ST25) and Qihai (CV6) points were selected for herb-partitioned moxibustion. Our results showed that herb-partitioned moxibustion improved visceral pain and down-regulated extracellular signal-regulated kinase, substance P, and neurokinin-1 protein and mRNA expression in dorsal root ganglia. These results indicate that down-regulation of extracellular signal-regulated kinase, substance P, and neurokinin-1 protein and mRNA may be a central mechanism for the analgesic effect of herb-partitioned moxibustion.

Seasonal-related effects on ammonium removal in activated carbon filter biologically enhanced by heterotrophic nitrifying bacteria for drinking water treatment.

To determine the potential effects of seasonal changes on water temperature and water quality upon removal of ammonium and organic carbon pollutants and to characterize the variations in microbial characteristics, a pilot-scale activated carbon filter biologically enhanced with heterotrophic nitrifying bacteria was investigated for 528 days. The results show that 69.2 ± 28.6% of ammonium and 23.1 ± 11.6% of the dissolved organic carbon were removed by the biologically enhanced activated carbon (BEAC) reactor. It is shown that higher biodegradable dissolved organic carbon enhances ammonium removal, even at low temperatures. The C/N ratio consumed by the BEAC reactor reached a steady value (i.e., 3.3) after 2 months of operation. Despite seasonal fluctuations and competition of the indigenous community, the heterotrophic nitrifying bacteria (Acinetobacter sp. HRBLi 16 and Acinetobacter harbinensis strain HITLi 7) remained relatively stable. The amount of carbon source was the most significant environmental parameter and dramatically affected the microbial community compositions in the BEAC reactor. The present study provides new insights into the application of a BEAC reactor for ammonium removal from drinking water, resisting strong seasonal changes.

Risk Factors and Outcomes in Patients With Hypernatremia and Sepsis.

BACKGROUND: Hypernatremia is an uncommon but important electrolyte abnormality in intensive care unit patients. Sepsis is one of the most common causes of intensive care unit admission, but few studies about the role of hypernatremia in sepsis has been published yet. In this study, we aimed to explore the risk factors for developing hypernatremia in patients with sepsis, and the prognosis of patients with sepsis with or without hypernatremia was also assessed. MATERIALS AND METHODS: In this retrospective cohort study of 51 septic intensive care unit patients at a single center, we examined the risk factors for the development of hypernatremia and the association of hypernatremia with clinical outcomes using univariate and multivariable analyses. Clinical outcomes such as mortality and hospital duration of patients with or without hypernatremia were also compared. RESULTS: Acute Physiology and Chronic Health Evaluation II score (odds ratio = 1.15; 95% CI: 1.022-1.294) was found to be the only independent risk factor for hypernatremia in patients with sepsis. Moreover, patients developing hypernatremia during hospitalization showed significantly higher morbidity and mortality. CONCLUSIONS: Acute Physiology and Chronic Health Evaluation II score may be an independent risk factor for hypernatremia in patients with sepsis. Moreover, hypernatremia is strongly associated with worse outcome in sepsis.

Ammonium removal of drinking water at low temperature by activated carbon filter biologically enhanced with heterotrophic nitrifying bacteria.

We sought to confirm whether use of Acinetobacter strains Y7 and Y16, both strains of heterotrophic nitrifying bacteria, was practical for removing ammonium (NH4 (+)-N) from drinking water at low temperatures. To test this, ammonium-containing drinking water was treated with strains Y7 and Y16 at 8 and 2 °C. Continuous ammonium treatment was conducted in order to evaluate the performance of three biologically enhanced activated carbon (BEAC) filters in removing ammonium. The three BEAC filters were inoculated with strain Y7, strain Y16, and a mixture of strains Y7 and Y16, respectively. A granular activated carbon (GAC) filter, without inoculation by any strains, was tested in parallel with the BEAC filters as control. The results indicated that NH4 (+)-N removal was significant when a BEAC filter was inoculated with the mixture of strains Y7 and Y16 (BEAC-III filter). Amounts of 0.44 ± 0.05 and 0.25 ± 0.05 mg L(-1) NH4 (+)-N were removed using the BEAC-III filter at 8 and 2 °C, respectively. These values were 2.8-4.0-fold higher than the values of ammonium removal acquired using the GAC filter. The synergistic effect of using strains Y7 and Y16 in concert was the cause of the high-ammonium removal efficiency achieved by using the BEAC-III filter at low temperatures. In addition, a high C/N ratio may promote NH4 (+)-N removal efficiency by improving biomass and microbial activity. This study provides new insight into the use of biofilters to achieve biological removal of ammonium at low temperature.

Purification and characterization of a low-temperature hydroxylamine oxidase from heterotrophic nitrifier Acinetobacter sp. Y16.

OBJECTIVE: To purify a low-temperature hydroxylamine oxidase (HAO) from a heterotrophic nitrifying bacterium Acinetobacter sp. Y16 and investigate the enzyme property. METHODS: A HAO was purified by an anion-exchange and gel-filtration chromatography from strain Y16. The purity and molecular mass were determined by RP-HPLC and SDS-PAGE. The HAO activity was detected by monitoring the reduction of potassium ferricyanide using hydroxylamine as substrate and ferricyanide as electron acceptor. The partial amino acid sequence was determined by mass spectrometry. RESULTS: The low-temperature HAO with a molecular mass of 61 kDa was purified from strain Y16 by an anion-exchange and gel-filtration chromatography. The enzyme exhibited an ability to oxidize hydroxylamine in wide temperature range (4-40 °C) in vitro using hydroxylamine as substrate and ferricyanide as electron acceptor. It was stable in the temperature range of 4 to 15 °C and pH range of 6.0 to 8.5 with less than 30% change in its activity. The optimal temperature and pH were 15 °C and 7.5, respectively. Three peptides were determined by mass spectrometry which were shown to be not identical to other reported HAOs. CONCLUSION: This is the first study to purify a low-temperature HAO from a heterotrophic nitrifier Acinetobacter sp. It differs from other reported HAOs in molecular mass and enzyme properties. The findings of the present study have suggested that the strain Y16 passes through a hydroxylamine-oxidizing process catalyzed by a low-temperature HAO for ammonium removal.

Organocatalytic enantioselective construction of multi-functionalized spiro oxindole dienes.

A diastereo- and enantio-selective domino Michael-cyclization-tautomerization reaction of isatylidene malononitriles with α,α-dicyanoalkenes catalyzed by a cinchona alkaloid-derived bifunctional thiourea catalyst has been developed. A series of multi-functionalized spiro oxindole diene derivatives have been obtained in good to excellent yields (up to 97%) with good to excellent enantioselectivities (up to 96%) as well as good diastereoselectivities (up to 7.9 : 1). In addition, an anomalous temperature effect on the enantioselectivity has also been studied for this transformation.

Organocatalytic asymmetric Michael addition of aliphatic aldehydes to indolylnitroalkenes: access to contiguous stereogenic tryptamine precursors.

Because of the importance of the indole framework and the versatile transformation of nitro and formyl groups, the efficient synthesis of optically pure 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanals, one type of tryptamine precursors are of great interest for pharmaceutical and biological research. Herein, the Michael addition of aliphatic aldehydes to indolylnitroalkenes has been developed using (S)-diphenylprolinol trimethylsilyl ether as an organocatalyst, which provides the desired optically pure syn 2-alkyl-3-(1H-indol-3-yl)-4-nitrobutanal derivatives in up to 98% yield with up to >99:1 dr and >99% ee. To show the synthetic usefulness of this methodology, optically active 2-alkyl-4-nitro-3-(1-tosyl-1H-indol-3-yl)butan-1-ol and tryptamine derivatives are readily obtained by stepwise systematic transformations.

Organocatalytic cascade aza-Michael/hemiacetal reaction between disubstituted hydrazines and α,ß-unsaturated aldehydes: Highly diastereo- and enantioselective synthesis of pyrazolidine derivatives.

The catalytic synthesis of nitrogen-containing heterocycles is of great importance to medicinal and synthetic chemists, and also a challenge for modern chemical methodology. In this paper, we report the synthesis of pyrazolidine derivatives through a domino aza-Michael/hemiacetal sequence with chiral or achiral secondary amines as organocatalysts. Thus, a series of achiral pyrazolidine derivatives were obtained with good yields (up to 90%) and high diastereoselectivities (>20:1) with pyrrolidine as an organocatalyst, and enantioenriched pyrazolidines are also achieved with good results (up to 86% yield, >10/1 regioselectivity, >20:1 dr, 99% ee) in the presence of (S)-diphenylprolinol trimethylsilyl ether catalyst.

Enantioselective construction of multifunctionalized spirocyclohexaneoxindoles through organocatalytic Michael-Aldol cyclization of isatin derived alkenes with linear dialdehydes.

Optically active spirocyclohexaneoxindole motifs are very important building blocks for preparations of biologically active complexes, natural products, and pharmaceutical compounds. Herein, we report the syntheses of enantiopure spirocyclohexaneoxindoles through domino Michael-Aldol reactions between isatin derived alkenes and pentane-1,5-dial in the presence of diphenylprolinol silyl ether as an aminocatalyst. As a result, a series of multistereogenic and functionalized spirocyclohexaneoxindoles have been obtained in good yields with moderate diastereoselectivities and excellent enantioselectivities. In addition, electronic circular dichroism (ECD) spectroscopy and time-dependent density functional theory (TD-DFT) were used to investigate the rational structures of spirocyclohexaneoxindoles.

Effects of total flavonoids from Drynaria fortunei on the proliferation and osteogenic differentiation of rat dental pulp stem cells.

Dental pulp stem cells (DPSCs) have the potential to form bone, nerve and fat, and are a candidate for use in regenerative medicine. Previous studies indicated that total flavonoids from Drynaria fortunei show a stimulative effect on the proliferation and osteogenic differentiation of osteoblastic MC3T3-E1 cells in vitro. This study aimed to investigate the effect of total flavonoids from Drynaria fortunei on the proliferation and osteogenic differentiation of rat DPSCs, and to further clarify the mechanisms involved. DPSCs were isolated by enzymatic digestion and identified using the CD44, CD29 and CD34 markers by immunohistochemistry, and exposed to 0.01, 0.05 and 0.1 g/l total flavonoids from Drynaria fortunei media. Total flavonoids from Drynaria fortunei promoted the proliferation of DPSCs in a dose-dependent manner and this effect may depend on the shortening of the G0/G1 phase and promotion of the S phase. Compared with the control group, the levels of alkaline phosphatase (ALP) and the expression of osteogenic genes increased with the concentrations of total flavonoids from Drynaria fortunei, and the volume and number of calcified nodules in the Drynaria groups was bigger compared to the control group. These results suggest that total flavonoid from Drynaria fortunei directly stimulates DPSC proliferation and osteogenic differentiation, and may serve as a new promising candidate drug for dental tissue engineering and bone regeneration.

Enantioselective synthesis of optically active cis-ß-thio-α-amino acid derivatives through an organocatalytic cascade thio-Michael/ring opening process.

Non-naturally enantioenriched cis-ß-thio-α-amino acid derivatives were synthesized through one pot, cascade thio-Michael/ring opening reaction of aromatic thiols with (Z)-olefinic azlactones in good yields with high levels of diastereoselectivities and enantioselectivities, which was catalyzed by a chiral bifunctional thiourea-tertiary amine catalyst.

[Capability and bacteria community analysis of an anaerobic baffled reactor treating soybean wastewater].

Capability and process characteristic of anaerobic baffled reactor (ABR) treating soybean wastewater were investigated in a 4-compartment ABR with an effective volume of 28 L. During an operation period of 100 days, the organic loading rate (OLR) increased by stages and its influence on the chemical oxygen demand (COD) removal efficiency was researched. The bacteria community structures in anaerobic activated sludge from different stages were also investigated by single-strand conformation polymorphism (SSCP) with the eubacterium universal primers SRV3-2P and BSF8/20, while the microbial genetic distance being analyzed by UPGMA communities clustering method. With an inoculated aerobic activated sludge of 18.0 g x L(-1) in terms of mixed liquor volatile suspend solid (MLVSS), the reactor started up at COD concentration of 2000 mg/L, hydraulic retention time (HRT) of 39.5 h and temperature of (35 +/- 1) degrees C for 31 d, the ABR achieved a stable state that resulted in 96% COD removal. When OLR increased stage by stage from 1.2 kg x (m3 x d)(-1) to 6.0 kg x (m3 x d)(-1), the reactor could performed steadily with a COD removal efficiency as high as 98%, and this indicated that compartmentalized ABR held a good performance during shock loadings. It was found that a step change in OLR had a remarkably effect on the structure and distribution of microbial communities in each compartment. With the organic loading rate increase, the genetic distances among the microbial communities in the compartments extended gradually, indicating that the specificity of microbial communities in each compartment was enhanced.