Construction of a novel rabbit model of ureteral calculi implanted with flowable resin.

BACKGROUND: The purpose of this study was to characterize the pathophysiological changes of hydronephrosis caused by ureteral calculi obstruction in a new rabbit ureteral calculi model by implanting flowable resin. METHODS: Forty New Zealand rabbits were randomly divided into two groups: the calculi group and the sham control group. In the calculi group (n = 20), rabbits were operated at left lower abdomen and the left ureter was exposed. Then flowable resin (flowable restorative dental materials) was injected into the left ureter using a 0.45 mm diameter intravenous infusion needle. Then light-cured for 40 s by means of a dental curing light to form calculi. In the sham control group, normal saline was injected into the ureter. Rabbits underwent X-ray and routine blood and urine tests preoperatively, as well as X-ray, CT, dissection, HE staining and routine blood and urine tests on 1, 3, 5 and 7 days postoperatively. Stone formation was assessed by X-ray and unenhanced CT scan after surgery. The pathophysiological changes were evaluated through dissection, HE staining and routine blood and urine tests. RESULTS: Ureteral calculi models were successfully constructed in 17 rabbits. In calculi group, high-density shadows were observed in the left lower abdomen on postoperative day 1st, 3rd, 5th and 7th by X-ray and CT scan. Dissection found obstruction formation of the left ureters, dilatation of the renal pelvis and upper ureter during 7 days after surgery. The renal long-diameters of the left ureters increased only on the 1st postoperative day. HE staining found ureteral and kidney damage after surgery. In calculi group and sham group,the serum creatinine, urea nitrogen, white blood cells and urine red blood cells were raised at day 1 after surgery. However, the indicators returned to normal at day 3, 5, and 7. CONCLUSIONS: This is a stable, less complicated operation and cost-effective ureteral calculi model by implanting flowable resin. And this novel model may allow us to further understand the pathophysiology changes caused by ureteral calculi obstruction.

In situ carbothermal synthesis of carbonized bacterial cellulose embedded with nano zero-valent iron for removal of Cr(VI).

Carbonized bacterial cellulose embedded with highly dispersed nano zero-valent iron (nZVI), denoted as nZVI@CBC, was prepared through one-step in situ carbothermal treatment of bacterial cellulose adsorbing iron(III) nitrate. The structure characteristics of nZVI@CBC and its performance in removing hexavalent chromium Cr(VI) were investigated. Results showed the formation of nZVI@CBC with a surface area of 409.61 m2/g at 800 °C, with nZVI particles of mean size 28.2 nm well distributed within the fibrous network of CBC. The stability of nZVI was enhanced by its carbon coating, despite some inevitable oxidation of exposed nZVI. Batch experiments demonstrated that nZVI@CBC exhibited superior removal efficiency compared to bare nZVI and CBC. Under optimal conditions, nZVI@CBC exhibited a high Cr(VI) adsorption capacity of up to 372.42 mg/g. Therefore, nZVI@CBC shows promise as an effective adsorbent for remediating Cr(VI) pollution in water.

Elevated CO2 aggravated polystyrene microplastics effects on the rice-soil system under field conditions.

Polystyrene microplastics (PS) are decomposed very slowly due to their recalcitrance and inevitably interact with the changing climate. How the interaction between PS and increasing CO2 concentration affects the plant-soil system is rarely investigated. Here, a free-air CO2 enrichment system in farm fields was used to study the impacts of PS added to soil at 10 mg kg-1 on rice and soil bacterial communities at different CO2 levels (ambient∼390 ppm and elevated∼590 ppm). Results showed that single PS interfered with Fe, Mn and Zn uptake of rice, and it increased the abundances of bacteria taxa assigned to N turnover and urease activities, leading to altered soil N transformation and availability. Elevated CO2 alone enhanced rice photosynthesis, decreased the abundances of nitrogen-fixation bacteria, and induced co-occurrence patterns between bacteria simplified and decentralized. Combined PS and elevated CO2 significantly decreased rice stomatal conductance and transpiration rate by 56.70% and 29.46%, respectively, and further inhibited elements uptake. Besides, combined exposure significantly disturbed bacterial amino acid metabolism, and stimulated the adaptative responses of resistant bacteria. Overall, this study revealed that increasing CO2 concentrations may exacerbate the impacts of PS on rice performance and soil bacterial communities, providing new insights into the interaction between microplastics and climate change.

Influence of pyrolysis temperature on characteristics and Cr(VI) adsorption performance of carbonaceous nanofibers derived from bacterial cellulose.

The effects of pyrolysis temperature on properties and adsorption performance of carbonized bacterial cellulose (CBC) produced from bacterial cellulose at 300, 400, 600 and 800 °C were investigated. As pyrolysis temperature increased, the BET surface area, C and ash contents of CBC increased while its mass yield and the contents of H, N and O decreased. Higher pyrolysis temperature resulted in CBC having more aromatic structure and less hydrophilic. The impacts of pyrolysis temperature, solution pH, contact time and initial concentration on the absorption of Cr(VI) onto CBC were systematically studied as well. The results showed that CBC400 prepared at 400 °C exhibited the highest Cr(VI) adsorption capacity for Cr(VI) up to 250.0 mg/g. The equilibrium adsorption and adsorption kinetics fitted the Langmuir isotherm and pseudo-second-order kinetic models well. The mechanisms of adsorption of Cr(VI) on CBC included electrostatic interaction, π-π interaction and functional groups complexation.

Polystyrene microplastics alleviate the effects of sulfamethazine on soil microbial communities at different CO2 concentrations.

Microplastics were reported to adsorb antibiotics and may modify their effects on soil systems. But there has been little research investigating how microplastics may affect the toxicities of antibiotics to microbes under future climate conditions. Here, we used a free-air CO2 enrichment system to investigate the responses of soil microbes to sulfamethazine (SMZ, 1 mg kg-1) in the presence of polystyrene microplastics (PS, 5 mg kg-1) at different CO2 concentrations (ambient at 380 ppm and elevated at 580 ppm). SMZ alone decreased bacterial diversity, negatively affected the bacterial structure and inter-relationships, and enriched the sulfonamide-resistance genes (sul1 and sul2) and class 1 integron (intl1). PS, at both CO2 conditions, showed little effect on soil bacteria but markedly alleviated SMZ's adverse effects on bacterial diversity, composition and structure, and inhibited sul1 transmission by decreasing the intl1 abundance. Elevated CO2 had limited modification in SMZ's disadvantages to microbial communities but markedly decreased the sul1 and sul2 abundance. Results indicated that increasing CO2 concentration or the presence of PS affected the responses of soil microbes to SMZ, providing new insights into the risk prediction of antibiotics under future climate conditions.

Exposure to microplastics impairs digestive performance, stimulates immune response and induces microbiota dysbiosis in the gut of juvenile guppy (Poecilia reticulata).

Microplastics (MPs) are widely distributing in aquatic environment. They are easily ingested by aquatic organisms and accumulate in digestive tract especially of intestine. To explore the potential effects of MPs on intestine, here we, using juvenile guppy (Poecilia reticulata) as experimental animal, investigated the response characteristics of digestion, immunity and gut microbiota. After exposure to 100 and 1000 µg/L concentrations of MPs (polystyrene; 32-40 µm diameters) for 28 days, we observed that MPs could exist in guppy gut and induce enlargement of goblet cells. Activities of digestive enzymes (trypsin, chymotrypsin, amylase and lipase) in guppy gut generally reduced. MPs stimulated the expression of immune cytokines (TNF-α, IFN-γ, TLR4 and IL-6). Through high throughput sequencing of 16S rRNA gene, decreases in diversity and evenness and changed composition of microbiota were found in guppy gut. PICRUSt analysis revealed that MPs might have effects on intestinal microbiota functions, such as inhibition of metabolism and repair pathway. Our findings suggested that MPs could retain in the gut of juvenile guppy, impair digestive performance, stimulate immune response and induce microbiota dysbiosis in guppy gut. The results obtained here provide new insights into the potential risks of MPs to aquatic animals.

The relationship between tooth loss and mortality from all causes, cardiovascular diseases, and coronary heart disease in the general population: systematic review and dose-response meta-analysis of prospective cohort studies.

Background: The association of tooth loss with mortality from all causes, cardiovascular diseases (CVD), and coronary heart disease (CHD) has been studied for many years; however, the results are inconsistent.Method: PubMed, Embase, Web of Knowledge, and Cochrane Oral Health Group's Trials Register databases were searched for papers published from 1966 to August 2018. We conducted dose-response meta-analysis to quantitatively evaluate the relation between tooth loss and risk of mortality from all causes, CVD, and CHD.Results: In the present study, 18 prospective studies conducted until August 2018 were considered eligible for analysis. In the analysis of linear association, the summarized relative risk (RR) values for each 10-, 20-, and 32-tooth loss for all-cause mortality were 1.15 (1.11-1.19), 1.33 (1.23-1.29), and 1.57 (1.39-1.51), respectively. Subgroup and sensitivity analyses showed consistent results. A linear relationship was found among all-cause mortality, with Pnonlinearity = 0.306. The susceptibility to all-cause mortality increased by almost 1.48 times at very high tooth loss (28-32), and slight flattening of the curve was noted. However, the summarized RR values for increment for 10-, 20-, and 32-tooth loss were not or were marginally related to increased risk of mortality from CVD/CHD. Subgroup and sensitivity analyses revealed inconsistent results. Tooth loss showed linear association with CHD mortality but not with CVD mortality. The susceptibility to all-cause mortality increased by almost 1.48 and 1.70 times for CVD and CHD, respectively, at very high tooth loss (28-32). The curve exhibited slight flattening; however, no statistical significance was detected.Conclusion: In the meta-analysis, our findings confirmed the positive relationship between tooth loss and susceptibility to all-cause mortality, but not for circulatory mortality. However, the finding that tooth loss might play a harmful role in the development of all-cause mortality remains inconclusive. Tooth loss may be a potential risk marker for all-cause mortality: however, their association must be further validated through large prospective studies.

Manufacture and cytotoxicity of a lead-free piezoelectric ceramic as a bone substitute-consolidation of porous lithium sodium potassium niobate by cold isostatic pressing.

AIM: The piezoelectric properties and cytotoxicity of a porous lead-free piezoelectric ceramic for use as a direct bone substitute were investigated. METHODOLOGY: Cold isostatic pressing (CIP) was applied to fabricate porous lithium sodium potassium niobate (Li0.06Na0.5K0.44) NbO3 specimens using a pore-forming method. The morphologies of the CIP-processed specimens were characterized and compared to those of specimens made by from conventional pressing procedures. The effects of the ceramic on the attachment and proliferation of osteoblasts isolated from the cranium of 1-day-old Sprague-Dawley rats were examined by a scanning electron microscopy (SEM) and methylthiazol tetrazolium (MTT) assay. RESULTS: The results showed that CIP enhanced piezoelectricity and biological performance of the niobate specimen, and also promoted an extracellular matrix-like topography of it. In vitro studies showed that the CIP-enhanced material had positive effects on the attachment and proliferation of osteoblasts. CONCLUSION: Niobate ceramic generated by CIP shows a promise for being a piezoelectric composite bone substitute.