In situ biomineralization reinforcing anisotropic nanocellulose scaffolds for guiding the differentiation of bone marrow-derived mesenchymal stem cells.

Nanocellulose (NC) is a promising biopolymer for various biomedical applications owing to its biocompatibility and low toxicity. However, it faces challenges in tissue engineering (TE) applications due to the inconsistency of the microenvironment within the NC-based scaffolds with target tissues, including anisotropy microstructure and biomechanics. To address this challenge, a facile swelling-induced nanofiber alignment and a novel in situ biomineralization reinforcement strategies were developed for the preparation of NC-based scaffolds with tunable anisotropic structure and mechanical strength for guiding the differentiation of bone marrow-derived mesenchymal stem cells for potential TE application. The bacterial cellulose (BC) and cellulose nanofibrils (CNFs) based scaffolds with tunable swelling anisotropic index in the range of 10-100 could be prepared by controlling the swelling medium. The in situ biomineralization efficiently reinforced the scaffolds with 2-4 times and 10-20 times modulus increasement for BC and CNFs, respectively. The scaffolds with higher mechanical strength were superior in supporting cell growth and proliferation, suggesting the potential application in TE application. This work demonstrated the feasibility of the proposed strategy in the preparation of scaffolds with mechanical anisotropy to induce cells-directed differentiation for TE applications.

A structure-functionality insight into the bioactivity of microbial polysaccharides toward biomedical applications: A review.

Microbial polysaccharides (MPs) are biopolymers secreted by microorganisms such as bacteria and fungi during their metabolic processes. Compared to polysaccharides derived from plants and animals, MPs have advantages such as wide sources, high production efficiency, and less susceptibility to natural environmental influences. The most attractive feature of MPs lies in their diverse biological activities, such as antioxidative, anti-tumor, antibacterial, and immunomodulatory activities, which have demonstrated immense potential for applications in functional foods, cosmetics, and biomedicine. These bioactivities are precisely regulated by their sophisticated molecular structure. However, the mechanisms underlying this precise regulation are not yet fully understood and continue to evolve. This article presents a comprehensive review of the most representative species of MPs, including their fermentation and purification processes and their biomedical applications in recent years. In particular, this work presents an in-depth analysis into the structure-activity relationships of MPs across multiple molecular levels. Additionally, this review discusses the challenges and prospects of investigating the structure-activity relationships, providing valuable insights into the broad and high-value utilization of MPs.

Biomarkers of Waterpipe Tobacco Smoke Exposure: A Systematic Review and Meta-Analysis.

INTRODUCTION: The prevalence of waterpipe tobacco smoking is increasing globally. Biomarkers of waterpipe tobacco smoke (WTS) exposure are less studied. AIMS AND METHODS: To identify the types of biomarkers of WTS exposure and estimate changes in biomarker concentrations pre- to post-WTS exposure. PubMed, Embase, Web of Science, CINAHL Plus, PsycINFO, and Cochrane Library were searched for studies up to April 24, 2023. The types of biomarkers were identified. Random-effects models were used to estimate changes in biomarker concentrations pre- to post-WTS exposure. RESULTS: Seventy-three studies involving 3755 participants exposed to WTS (49% male, mean age: 24.8 years) and 11 types of biomarkers of WTS exposure were identified. The biomarkers included tobacco alkaloids, expired carbon monoxide (eCO), carboxyhemoglobin (COHb), tobacco-specific nitrosamines, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, unmetabolized VOCs, unmetabolized PAHs, furan metabolites, and heterocyclic aromatic amines. Compared with pre-WTS exposure, eCO (breath; mean difference [MD] 27.00 ppm; 95% confidence interval [CI]: 20.91 to 33.08), COHb (blood; MD 4.30%; 95%CI: 2.57 to 6.03), COHb (breath; MD 7.14%; 95%CI: 4.96 to 9.31), nicotine (blood; MD 8.23 ng/mL; 95%CI: 6.27 to 10.19), and cotinine (urine; MD 110.40 ng/mL; 95%CI: 46.26 to 174.54) significantly increased post-WTS exposure. CONCLUSIONS: Biomarkers of WTS exposure were systematically identified. The similarity between the biomarkers of WTS exposure and those of cigarette smoke and higher concentrations of some biomarkers post-WTS exposure underscore the need for further research on applying biomarkers in surveillance, interventions, and regulations to mitigate the harms of waterpipe tobacco smoking. IMPLICATIONS: This study provides the first comprehensive overview of biomarkers investigated and available for assessing WTS exposure and their concentration changes in the human body. Researchers can use biomarkers such as eCO, COHb, nicotine, and cotinine to measure the health risks associated with WTS exposure and objectively evaluate the effectiveness of public health interventions aimed at reducing waterpipe tobacco smoking. Public health policymaking can also be informed through increased biomarker concentrations following WTS exposure, to implement regulations and public health education campaigns on limiting or preventing waterpipe tobacco smoking.

Self-assembly of cell-embedding reduced graphene oxide/ polypyrrole hydrogel as efficient anode for high-performance microbial fuel cell.

A three-dimensional (3D) macroporous reduced graphene oxide/polypyrrole (rGO/Ppy) hydrogel assembled by bacterial cells was fabricated and applied for microbial fuel cells. By taking the advantage of electroactive cell-induced bioreduction of graphene oxide and in-situ polymerization of Ppy, a facile self-assembly by Shewanella oneidensis MR-1and in-situ polymerization approach for 3D rGO/Ppy hydrogel preparation was developed. This facile one-step self-assembly process enabled the embedding of living electroactive cells inside the hydrogel electrode, which showed an interconnected 3D macroporous structures with high conductivity and biocompatibility. Electrochemical analysis indicated that the self-assembly of cell-embedding rGO/Ppy hydrogel enhanced the electrochemical activity of the bioelectrode and reduced the electron charge transfer resistance between the cells and the electrode. Impressively, extremely high power output of 3366 ± 42 mW m-2 was achieved from the MFC with cell-embedding rGO/Ppy hydrogel rGO/Ppy, which was 8.6 times of that delivered from the MFC with bare electrode. Further analysis indicated that the increased cell loading by the hydrogel and improved electrochemical activity by the rGO/Ppy composite would be the underlying mechanism for this performance improvement. This study provided a facile approach to fabricate the biocompatible and electrochemical active 3D nanocomposites for MFC, which would also be promising for performance optimization of various bioelectrochemical systems.

Medical insurance payment schemes and patient medical expenses: a cross-sectional study of lung cancer patients in urban China.

BACKGROUND: As the main cause of cancer death, lung cancer imposes seriously health and economic burdens on individuals, families, and the health system. In China, there is no national study analyzing the hospitalization expenditures of different payment methods by lung cancer inpatients. Based on the 2010-2016 database of insured urban resident lung cancer inpatients from the China Medical Insurance Research Association (CHIRA), this paper aims to investigate the characteristics and cost of hospitalized lung cancer patient, to examine the differences in hospital expenses and patient out-of-pocket (OOP) expenses under four medical insurance payment methods: fee-for-service (FFS), per-diem payments, capitation payments (CAP) and case-based payments, and to explore the medical insurance payment method that can be conducive to controlling the cost of lung cancer. METHOD: This is a 2010-2016, 7-year cross-sectional study. CHIRA data are not available to researchers after 2016. The Medical Insurance Database of CHIRA was screened using the international disease classification system to yield 28,200 inpatients diagnosed with lung cancer (ICD-10: C34, C34.0, C34.1, C34.2, C34.3, C34.8, C34.9). The study includes descriptive analysis and regression analysis based on generalized linear models (GLM). RESULTS: The average patient age was 63.4 years and the average length of hospital stay (ALOS) was 14.2 day; 60.7% of patients were from tertiary hospitals; and 45% were insured by FFS. The per-diem payment had the lowest hospital expenses (RMB7496.00/US$1176.87), while CAP had the lowest OOP expenses (RMB1328.18/US$208.52). Compared with FFS hospital expenses, per-diem was 21.3% lower (95% CI = -0.265, -0.215) and case-based payment was 8.4% lower (95% CI = -0.151, -0.024). Compared with the FFS, OOP expenses, per-diem payments were 9.2% lower (95% CI = -0.130, -0.063) and CAP was 15.1% lower (95% CI = -0.151, -0.024). CONCLUSION: For lung cancer patients, per-diem payment generated the lowest hospital expenses, while CAP meant patients bore the lowest OOP costs. Policy makers are suggested to give priority to case-based payments to achieve a tripartite balance among medical insurers, hospitals, and insured members. We also recommend future studies comparing the disparities of various diseases for the cause of different medical insurance schemes.

Gross perianal embryonal rhabdomyosarcoma with severe multiple bone metastases throughout the body: a case report.

In adults, embryonal rhabdomyosarcoma (ERMS) is rare and has a poor prognosis. Giant perianal ERMS with severe multiple bone metastases at initial diagnosis has not been reported and lacks effective treatment options. This current case report describes a 31-year-old female patient that presented with a large lump on the right side of the anus. ERMS was diagnosed, accompanied by multiple bone metastases throughout the body and severe thrombocytopenia. She had an extremely low platelet count at initial diagnosis, making systemic chemotherapy inappropriate. Genetic testing did not help identify effective targeted drugs. A multi-target tyrosine kinase inhibitor, anlotinib, was selected to control the tumours combined with local radiotherapy to relieve pain. The lump became smaller and this reduction was maintained for 5 months. At 7 months after the diagnosis, the patient died of thrombocytopenia. This current case may provide supportive evidence for a potential treatment for patients with advanced ERMS, especially those not suitable for chemotherapy or surgery.

Brain metastasis in de novo breast cancer: An updated population-level study from SEER database.

PURPOSE: Although there are current studies on breast cancer brain metastasis, population-level analysis is still lacking. As treatment for metastatic breast cancer has improved, an updated population-level analysis is necessary. Our aim was to use the SEER database to characterize the incidence and survival of patients with brain metastases at the initial diagnosis of breast cancer. PATIENTS AND METHODS: Patients with breast cancer from 2010 to 2018 were identified using the SEER database. The stratified incidence and median survival of patients with BM at diagnosis were described. Multivariate logistic and Cox regression were performed to determine the covariates associated with brain metastasis and survival outcomes, respectively. Multiple comparisons based on Cox proportional hazards model were performed for the analysis of interactive effects on overall survival. RESULTS: A total of 2,248 patients with brain metastases at the initial diagnosis of breast cancer were identified, accounting for 0.40% of all patients with breast cancer, and 7.26% of patients with metastatic disease. Incidence proportions were highest, and survival outcomes were worst among patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive and triple-negative subtypes. For patients with brain metastases, the prognostic differences among different molecular subtypes have been gradually narrowing, and the survival benefits from various treatment methods have been all increased over time. CONCLUSION: Our study provides an updated population-level estimate of the incidence and survival for patients with brain metastases at the diagnosis of breast cancer, thus may help early identification, prognostic stratification and treatment planning for such patients.

Co-pyrolysis of microalgae and other biomass wastes for the production of high-quality bio-oil: Progress and prospective.

Microalgae are the most prospective raw materials for the production of biofuels, pyrolysis is an effective method to convert biomass into bioenergy. However, biofuels derived from the pyrolysis of microalgae exhibit poor fuel properties due to high content of moisture and protein. Co-pyrolysis is a simple and efficient method to produce high-quality bio-oil from two or more materials. Tires, plastics, and bamboo waste are the optimal co-feedstocks based on the improvement of yield and quality of bio-oil. Moreover, adding catalysts, especially CaO and Cu/HZSM-5, can enhance the quality of bio-oil by increasing aromatics content and decreasing oxygenated and nitrogenous compounds. Consequently, this paper provides a critical review of the production of bio-oil from co-pyrolysis of microalgae with other biomass wastes. Meanwhile, the underlying mechanism of synergistic effects and the catalytic effect on co-pyrolysis are discussed. Finally, the economic viability and prospects of microalgae co-pyrolysis are summarized.

Yeast-induced formation of graphene hydrogels anode for efficient xylose-fueled microbial fuel cells.

Microbial fuel cells (MFCs) are of great interest due to their capability to directly convert organic compounds to electric energy. In particular, MFCs technology showed great potential to directly harness the energy from xylose in the form of bioelectricity and biohydrogen simultaneously. Herein, we report a yeast strain of Cystobasidium slooffiae JSUX1 enabled the reduction and assembly of graphene oxide (GO) nanosheets into three-dimensional reduced GO (3D rGO) hydrogels on the surface of carbon felt (CF) anode. The autonomously self-modified 3D rGO hydrogel anode entitled the yeast-based MFCs with two times enhancement on bioelectricity and biohydrogen production from xylose. Further analysis demonstrated that the 3D rGO hydrogel attracted more yeast cells and reduced the interfacial charge transfer resistance, which was the underlying mechanism for the improvement of MFCs performance. This work offers a new strategy to reinforce the performance of yeast-based MFCs and provides a new opportunity to efficiently harvest energy from xylose.

Survival Benefit of Surgical Treatment Added Into Systemic Treatment for Isolated Breast Cancer Liver Metastases: A Systematic Review and Meta-Analysis.

Background: Compared with systemic treatment alone, whether surgical treatment combined with systemic treatment can improve survival outcomes of patients with isolated breast cancer liver metastases (BCLM) is still controversial. This meta-analysis was designed to evaluate the efficacy of surgical treatment for patients with isolated BCLM. Methods: A systematic search of PubMed, Embase, and Cochrane Library up to May 13, 2021 was conducted for relevant studies. The primary outcome was overall survival. The meta-analysis was performed using R software. The quality of the pooled study was assessed using the Newcastle-Ottawa scale. The publication bias was evaluated by funnel plots and Begg's and Egger's tests. Fixed- and random-effects models were applied according to heterogeneity. Results: 9 retrospective studies involving 13 cohorts (7 unmatched cohorts and 6 matched cohorts) were included in this study. The surgical cohorts had better overall survival than the systemic cohorts in the pooled analysis of all the included studies, in the subgroup analysis of liver resection, and in the subset of the matched cohorts. Conclusions: Compared with systemic treatment alone, surgical treatment combined with systemic treatment was proven to be associated with superior survival outcomes, which should be considered in selected patients with isolated BCLM.

Transperineal core-needle biopsy of a rectal subepithelial lesion guided by endorectal ultrasound after contrast-enhanced ultrasound: A case report.

BACKGROUND: Rectal subepithelial lesions (SELs) are commonly seen in endoscopic examination, generally manifested as bumps with a smooth surface. Precise preoperative diagnoses for rectal SELs are difficult because abnormal tissues are not easily to be obtained by regular endoscopic forceps biopsy. Traditional guidance modalities of preoperative biopsy, including endoscopic ultrasound, computed tomography, and transabdominal ultrasound, are often unsatisfactory. An updated, safe, and effective biopsy guidance method is required. We herein report a new biopsy guidance modality-endorectal ultrasound (ERUS) combined with contrast-enhanced ultrasound (CEUS). CASE SUMMARY: A 32-year-old woman complained of a mass inside the rectovaginal space for 9 years, which became enlarged within 1 year. A rectal SEL detected by endoscopy was suspected to be a gastrointestinal stromal tumor or exophytic uterine fibroid. Pathological diagnosis was difficult because of unsuccessful transabdominal core needle biopsy with insufficient tissues, as well as vaginal hemorrhage. A second biopsy was suggested after multiple disciplinary treatment discussion, which referred to a transperineal core needle biopsy (CNB) guided by ERUS combined with CEUS. Adequate samples were procured and rectal gastrointestinal stromal tumor was proved to be the pathological diagnosis. Imatinib was recommended for first-line therapy by multiple disciplinary treatment discussion. After the tumor shrunk, resection of the rectal gastrointestinal stromal tumor was performed through the posterior vaginal wall. Adjuvant therapy was applied and no recurrence or metastasis has been found by the last follow-up on December 13, 2019. CONCLUSION: Transperineal CNB guided by ERUS and CEUS is a safe and effective preoperative biopsy of rectal SELs yet with some limitations.

Exosomes secreted by chemoresistant ovarian cancer cells promote angiogenesis.

BACKGROUND: Ovarian cancer (OC) has the highest mortality rate in gynecologic tumors. Despite decades of continuous efforts, the survival rate of patients has not improved significantly, mostly due to drug resistance. Exosomes are hot topics in recent years. Cells can affect the biological behaviors of other cells by transferring exosomes. So far, numerous researchers have found that tumor cells can secrete exosomes which play a important role in the development of tumors. Solid tumors can promote angiogenesis. When drug resistance occurs, it seems that more blood vessels form. We suppose that exosomes derived from chemoresistant OC cells can also promote angiogenesis. RESULTS: We investigate whether exosomes secreted by chemoresistant SKOV3-DDP cells (SKOV3-DDP-exo) and sensitive SKOV3 cells (SKOV3-exo) influence angiogenesis. After exosomes were extracted, exosomes were co-cultured with HUVECs. We found that SKOV3-DDP-exo and SKOV3-exo are absorbed by endothelial cells and promote the proliferation, migration, invasion and tube formation of endothelial cells. Moreover, SKOV3-DDP-exo is more powerful in angiogenesis, suggesting that parts of the components of SKOV3-DDP-exo are significantly radical. We also found that miR-130a was highly expressed in drug-resistant OC cells. Also, we found that miR-130a in SKOV3-DDP-exo is higher than SKOV3-exo. Therefore, we suggest that miR-130a in exosomes is the main cause of chemoresistant OC cells promoting angiogenesis.

Risk factors for pregnancy-associated venous thromboembolism in Singapore.

OBJECTIVES: Pregnancy-associated venous thromboembolism (VTE), including deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with increased risk of maternal mortality and morbidity. This study aimed to assess potential risk factors for pregnancy-associated VTE. METHODS: In this case-control study, women with pregnancy-associated VTE were identified via International Classification of Diseases codes and included if they had been objectively diagnosed with VTE during pregnancy or within six weeks postpartum, from 2004 to 2016, at KK Women's and Children's Hospital or Singapore General Hospital in Singapore. Controls, i.e. pregnant women without VTE, were selected from a prospective longitudinal study. The odds ratio (OR) for VTE was computed for a range of maternal and obstetric factors. RESULTS AND CONCLUSIONS: From 2004 to 2016, 89 cases of pregnancy-associated VTE and 926 controls were identifed and analysed using logistic regression. The most significant risk factors for pregnancy-associated VTE were smoking (OR 5.44, p=0.0002) and preterm delivery (OR 5.06, p=0.023). Malay race, multiparity, non-O blood group and caesarean section, were also identified to be of higher risk. These risk factors should be useful in the development of thromboprophylaxis strategies for pregnancy and the postpartum period, especially in Singapore.

Nanodiamond-based microRNA delivery system promotes pluripotent stem cells toward myocardiogenic reprogramming.

BACKGROUND: Gene therapy is the advanced therapeutics for supplying or replacing the genetic material in patients with inherited disorders. Recent clinical studies have made some progress in a wide range of applications, including monogenic disorders, neurodegenerative diseases, malignant tumors, and congenital diseases. Heart diseases, especially myocardial ischemia, remain one of the leading causes of mortality worldwide and usually result in irreparable cardiomyocyte damage and severe heart failure. METHODS: Most advances in induced pluripotent stem cell (iPSC) technologies for promoting regenerative medicine and stem cell research. However, the driver molecules of myocardial-lineage differentiation and the functional reconstruction capacity of iPSC-derived cardiomyocytes are still an open question. Nanomedicine-based gene delivery provided a crucial platform to carry on the biogenomic materials for equipping functionalities and engineering the living organ environment. Nanodiamond (ND), a carbon-based nanomaterial, has been discovered and shown the high biocompatible and less toxicity for transporting protein, drug, and genomic plasmids. RESULTS: Here, we applied ND as a gene delivery vehicle to carry microRNA (miR-181a), and then transfected into iPS to promote cardiomyocyte-lineage differentiation. Notably, miR-181a plays a key role in iPS-derived cardiomyocyte differentiation which directly targets Hox-A11, leading to elevated MyoD expression and enhanced cardiomyocyte differentiation. CONCLUSION: Our study demonstrated that miR-181a promotes iPSC differentiation into functional cardiomyocytes. Delivery of NANO-DIAMOND-miR-181a may host clinical potential to enhance the differentiation and recovery of the cardiogenic function in injured cardiomyocytes.

Bioflocculants Produced by Bacterial Strains Isolated from Palm Oil Mill Effluent for Application in the Removal of Eriochrome Black T Dye from Water.

Four strains of bioflocculant-producing bacteria were isolated from a palm oil mill effluent (POME). The four bacterial strains were identified as Pseudomonas alcaliphila (B1), Pseudomonas oleovorans (B2), Pseudomonas chengduensis (B3), and Bacillus nitratireducens (B4) by molecular identification. Among the four bacterial strains, Bacillus nitratireducens (B4) achieved the highest flocculating activity (49.15%) towards kaolin clay suspension after eight hours of cultivation time and was selected for further studies. The optimum conditions for Eriochrome Black T (EBT) flocculation regarding initial pH, type of cation, and B4 dosage were determined to be pH 2, Ca2⁺ cations, and a dosage of 250 mL/L of nutrient broth containing B4. Under these conditions, above 90% of EBT dye removal was attained. Fourier transform infrared spectroscopic (FT-IR) analysis of the bioflocculant revealed the presence of hydroxyl, alkyl, carboxyl, and amino groups. This bioflocculant was demonstrated to possess a good flocculating activity, being a promissory, low-cost, harmless, and environmentally friendly alternative for the treatment of effluents contaminated with dyes.

Clinical efficacy of adjuvant chemotherapy in the treatment of pT4 stage II colorectal cancer with defective mismatch repair status: A protocol for systematic review and meta-analysis.

BACKGROUND: The aim of this systematic review and meta-analysis is to assess the efficacy of adjuvant chemotherapy in patients with stage IIB/C CRC and defective mismatch repair (dMMr) status, and to evaluate what is the determinant risk factor for adjuvant chemotherapy in those patients. METHOD: A systematic search of PubMed, EMBASE, Web of science, Cochrane Library databases will be performed. All RCTs published in electronic databases from inception to March 19, 2020, with language restricted in English will be included in this review study. Two reviewers will independently perform the Study selection, data extraction, quality assessment, and assessment of risk bias and will be supervised by third party. Outcomes consisted of overall survival, progression-free survival and sufficient information to extract hazard ratios and their 95% confidence intervals and it will be calculated to present the prognostic role of adjuvant chemotherapy in patients with stage IIB/C CRC and dMMR status using Review Manager version 5.3 when there is sufficient available data. RESULTS: The results of this systematic review and meta-analysis will be submitted to a peer-reviewed journal for publication. CONCLUSION: This study will summarize up-to-date evidence to assess the efficacy of adjuvant chemotherapy in patients with stage IIB/C CRC and dMMR status and provide a scientific and practical suggestions for treatment decision-making. REGISTRATION: This protocol has been registered on the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) with a registration number of INPLASY202050019.

Rare case of drain-site hernia after laparoscopic surgery and a novel strategy of prevention: A case report.

BACKGROUND: Trocar site hernia (TSH) is a rare but potentially dangerous complication of laparoscopic surgery, and the drain-site TSH is an even rarer type. Due to the difficulty to diagnose at early stages, TSH often leads to a delay in surgical intervention and eventually results in life-threatening consequences. Herein, we report an unusual case of drain-site TSH, followed by a brief literature review. Finally, we provide a novel, simple, and practical method of prevention. CASE SUMMARY: A 54-year-old female patient underwent laparoscopic subtotal hysterectomy and bilateral adnexectomy for uterine fibroids 8 d ago in another hospital. She was admitted to our hospital with a 2-d history of intermittent abdominal pain, nausea, vomiting, and abdominal enlargement with an inability to pass stool and flatus. The emergency computed tomography scan revealed the small bowel herniated through a 10 mm trocar incision, which was used as a drainage port, with diffuse bowel distension and multiple air-fluid levels with gas in the small intestines. She was diagnosed with drain-site strangulated TSH. The emergency exploratory laparotomy confirmed the diagnosis. A herniorrhaphy followed by standard intestinal resection and anastomosis were performed. The patient recovered well after the operation and was discharged on postoperative day 8 and had no postoperative complications at her 2-wk follow-up visit. CONCLUSION: TSH must be kept in mind during the differential diagnosis of post-laparoscopic obstruction, especially after the removal of the drainage tube, to avoid the serious consequences caused by delayed diagnosis. Furthermore, all abdomen layers should be carefully closed under direct vision at the trocar port site, especially where the drainage tube was placed. Our simple and practical method of prevention may be a novel strategy worthy of clinical promotion.

The Antimethanogenic Nitrocompounds Can be Cleaved into Nitrite by Rumen Microorganisms: A Comparison of Nitroethane, 2-Nitroethanol, and 2-Nitro-1-propanol.

A class of aliphatic short chain nitrocompounds have been reported as being capable of CH4 reduction both in vitro and in vivo. However, the laboratory evidence associated with the metabolic fate of nitrocompounds in the rumen has not been well documented. The present study was conducted to compare in vitro degradation and metabolism of nitroethane (NE), 2-nitroethanol (NEOH), and 2-nitro-1-propanol (NPOH) incubated with mixed rumen microorganisms of dairy cows. After 10 mM supplementation of nitrocompounds, a serious of batch cultures were carried out for 120 h under the presence of two substrates differing in the ratio of maize meal to alfalfa hay (HF, 1:4; LF, 4:1). Compared to the control, methane production was reduced by 59% in NPOH and by >97% in both NE and NEOH, and such antimethanogenic effects were more pronounced in the LF than the HF group. Although NE, NEOH, and NPOH addition did not alter total VFA production, the rumen fermentation pattern shifted toward increasing propionate and butyrate and decreasing acetate production. The kinetic disappearance of each nitrocompound was well fitted to the one-compartment model, and the disappearance rate (k, %/h) of NE was 2.6 to 5.2 times greater than those of NEOH and NPOH. Higher intermediates of nitrite occurred in NEOH in comparison with NPOH and NE while ammonia N production was lowest in NEOH. Consequently, a stepwise accumulation of bacterial crude protein (BCP) in response to the nitrocompound addition was observed in both the HF and LF group. In brief, both NE and NEOH in comparison with NPOH presented greater antimethanogenic activity via the shift of rumen fermentation. In addition, the present study provided the first direct evidence that rumen microbes were able to cleave these nitrocompounds into nitrite, and the subsequent metabolism of nitrite into ammonia N may enhance the growth of rumen microbes or promote microbial activities.

[Heavy Metal Pollution Characteristics and Ecological and Health Risk Assessment of Atmospheric PM2.5 in a Living Area of Zhengzhou City].

To study the pollution characteristics of atmospheric heavy metal elements in a living area of Zhengzhou City, assess the potential ecological risks, and determine risks to resident health in this city, the Wuhan Tianhong TH-16A Airborne Particles Intelligent Sampler was used to collect atmospheric PM2.5 in Zhengzhou City. The mass concentrations of 17 metal elements were analyzed by ambient air determination of inorganic elements by ambient particle matter wavelength dispersive X-ray fluorescence spectrometry. The source of heavy metals was analyzed by the enrichment factor method and principal component analysis. The ecological risk index method and the US Environmental Protection Agency's health risk assessment method were used to evaluate the potential ecological risks and residents' health risks from Cr, Cd, Cu, Zn, Ni, Pb, As, and other elements. The results showed that metals with higher enrichment factor values were Cd, Sb, Pb, and As, and Cd had the highest enrichment factor value. The sources of metal elements in a living area of Zhengzhou City were mainly crust/burning coal, fuel, garbage burning, metallurgical dust, and vehicle emission. The single factor potential ecological hazard index values of Cd, Pb, Zn, As, Cu, Ni, and Cr were 70420.2, 255.3, 204.6, 71.5, 36.9, 24.0, and 5.1, respectively. Cd, As, and Cr in a living area of Zhengzhou City posed a cancer risk, and Cd was the most harmful. Mn had a non-carcinogenic risk.

[Emission Characteristics Analysis and Health Risk Assessment of Unorganized VOCs in the Carbon Industry, Zhengzhou].

The three typical carbon enterprises in Zhengzhou were selected as research targets, and the emission characteristics of volatile organic compounds (VOCs) and their ozone formation potential (OFP) in different functional areas were studied. The US Environmental Protection Agency (EPA) health risk assessment model was used to evaluate the health risks of VOCs emitted by the carbon industry. The results showed that the concentration of VOCs in the production areas of the three research enterprises was between 89.77-964.60 µg·m-3, and the management area was between 51.46-121.59 µg·m-3. Naphthalene and carbon disulfide were at the highest concentrations in the carbon plants. The ozone formation potential of VOCs in the production area was between 75.42-1416.73 µg·m-3, and in the management area was between 65.32-202.42 µg·m-3, mainly from the contribution of aromatic hydrocarbons and olefins. The carcinogenic health risk (Risk) of VOCs in the production area was 3.5×10-5-2.8×10-3, and in the management area was 2.0×10-5-9.4×10-5, which was higher than the maximum acceptable level recommended by the EPA (10-6). The non-carcinogenic health risk index (HI) of the VOCs in the production area was 3.2-1.4×102, and in the management area was 4.3×10-1-3.8, except for the management area of the first enterprise, which was greater than 1, which may expose the workers. These health factors cause cancer and non-carcinogenic hazards.