Key factors affecting NH3-N in the Huaihe River Basin due to human activities.

Human activity factors have a significant impact on changes in ammonia nitrogen (NH3-N) content in rivers. Existing research mainly focuses on human activity factors as type factors, and lacks research on the key factors affecting river NH3-N among human activity factors. Therefore, this paper aims to study the key factors affecting human activities on NH3-N in the Huaihe River through various statistical analysis methods. The study found that changes in NH3-N content in the Huaihe River are mainly affected by land use patterns in the basin. There are two different ways in which land use affects NH3-N in rivers: direct effects and indirect effects. We also studied the main pathways through which changes in key factors in human activities affect NH3-N in the Huaihe River by constructing a structural equation model. The results showed that crop sowing area and afforestation area have a significant direct effect on NH3-N in the Huaihe River. In addition, crop sowing area and afforestation area can also affect river NH3-N by regulating the amount of nitrogen fertilizer and human excrement. This study is of great significance for understanding how human activities regulate NH3-N content in rivers.

Effect and mechanism of Mn2+ on urease activity during anaerobic biological treatment of landfill leachate.

As a crucial hydrolytic enzyme, urease plays a vital role in anaerobic biological treatment. It is well-known that manganese ions are abundant in landfill leachate, but their concentration fluctuates significantly. However, few studies have investigated the effect and mechanism of different concentrations of Mn2+ on urease activity during anaerobic biological treatment of landfill leachate. This paper aimed to investigate the effects and mechanisms of different concentrations of Mn2+ on urease activity. The results showed that an appropriate amount of Mn2+ could significantly enhance urease activity, while a high concentration of Mn2+ could inhibit it. Insight into the mechanisms behind this phenomenon, various methods such as Zeta potential, particle size, ultraviolet spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and statistical analysis were employed in our study. Research suggested that, on one hand, Mn2+ may form hydrogen bonds with the side chain amino or carboxyl groups of urease amino acid residues, affecting the structure of urease through hydrogen bonding. Additionally, Mn2+ also binds to urease through hydrophobic interactions. On the other hand, the C-OH and C-N functional groups in urease have a strong affinity for Mn2+, and changes in these functional groups can greatly enhance the activity of urease. Furthermore, under the action of high concentrations of Mn2+, while the structure of urease becomes more stable, there is also a steric hindrance phenomenon that affects the substrate from entering the catalytic center. Therefore, studying the mechanism of Mn2+ affecting urease activity has significant biological significance and provides a new perspective for exploring the impact of metals on anaerobic bioprocessing of landfill leachate.

Ag Nanoparticle and Ti-MOF Cooperativity for Efficient Inactivation of E. coli in Water.

Because of the limitations of traditional chlorine-based bactericidal water treatment, such as the formation of disinfection byproducts (DBPs) and resistance to chlorine, novel approaches and materials are required for effective disinfection of water. This study focuses on the development of a new sterilization material, Ag/NH2-MIL-125(Ti), which was designed to effectively inactivate Escherichia coli in water. The effectiveness of the as-designed material stems from the synergistic interactions between Ag nanoparticles (NPs) and photoactive metal-organic frameworks (MOFs). In this complex material, the MOFs play a critical role in dispersing and isolating the Ag NPs, thus preventing undesirable aggregation during bacterial inactivation. Simultaneously, Ag NPs enhance the photocatalytic performance of the MOFs. Sterilization experiments demonstrate the remarkable rapid E. coli inactivation performance of Ag/NH2-MIL-125(Ti) under illuminated and nonilluminated conditions. Within 25 min of visible light exposure, the as-prepared material achieves a >7-log E. coli reduction. In addition, Ag/NH2-MIL-125(Ti) efficiently decomposes acetic acid, which is the main DBP precursor, under visible light irradiation. Mechanistic investigations revealed that •O2- and h+ were the primary active substances responsible for the inactivation of E. coli and the decomposition of acetic acid, respectively.

The Effects of Angiosome Morphology on Choke Vessels and Flap Necrosis in a Rat Multiterritory Perforator Flap.

BACKGROUND: Although the angiosome concept has been proposed for a long time, very few studies have been done on its morphology. Our study investigated the effects of angiosome morphology on choke vessels and flap necrosis in a rat multiterritory perforator flap. METHODS: Seventy-two male Sprague-Dawley rats were randomly divided into 3 groups (n = 24/group). The flap contained the right iliolumbar, posterior intercostal, and thoracodorsal angiosomes (TDAVs), termed angiosomes I, II, and III, respectively. Only the posterior intercostal artery and iliolumbar vein were preserved in group 1, whereas only the posterior intercostal artery and vein were preserved in group 2, and only the posterior intercostal artery and thoracodorsal vein were preserved in group 3. Distances from angiosome II to angiosome I (II-I), angiosome II to angiosome III (II-III), angiosome I to the caudal side of the flap (I-caudal), and angiosome III to the cranial side of the flap (III-cranial) were measured. Arteriography, flap necrosis, average microvascular density, and vascular endothelial growth factor expression were evaluated. RESULTS: The II-I distance was significantly greater than that of II-III (3.853 ± 0.488 versus 3.274 ± 0.433 cm, P = 0.012), whereas the distance of I-caudal resembled that of III-cranial (1.062 ± 0.237 versus 0.979 ± 0.236 cm, P = 0.442). The iliolumbar and posterior intercostal angiosomes were multidirectional, whereas the TDAV was craniocaudal and unidirectional. Seven days after the operation, the choke arteries had transformed into true anastomotic arteries. Flap necrosis was lowest in group 3, followed by group 2, and highest in group 1 (10.5% ± 2.4% versus 18.3% ± 3.5% versus 25.5% ± 4.6%, P < 0.01), whereas group 3 showed the highest microvascular density and vascular endothelial growth factor expression, in contrast to groups 2 and 1, with the lowest. CONCLUSIONS: The choke vessel adjacent to the craniocaudal and unidirectional TDAV significantly blocked venous return. Increasing venous return may reduce the necrosis.

Remediating thiacloprid-contaminated soil utilizing straw biochar-loaded iron and manganese oxides activated persulfate: Removal effects and soil environment changes.

Thiacloprid (THI) has accumulated significantly in agricultural soil. Herein, a novel approach to removing THI was explored by straw biochar-loaded iron and manganese oxides (FeMn@BC) to activate the persulfate (PS). The factors influencing the removal of 5 mg kg-1 THI from the soil by FeMn@BC/PS were investigated, including FeMn@BC dosing, PS dosing, temperature, and soil microorganisms. The feasibility was demonstrated by the 75.22% removal rate of THI with 3% FeMn@BC and 2% PS at 7 days and a 92.50% removal rate within 60 days. Compared to the THI, NH4+-N and available potassium were 3.96 and 3.25 times, and urease and phosphatase activities were increased by 22.54% and 33.28% in the FeMn@BC/PS at the 15 days, respectively. THI was found to seriously alter the structure of the genus in the 15 days by 16 S rRNA analysis; however, the FeMn@BC/PS group alleviated the damage, compared to the THI with 658 more operational taxonomic units. Actinobacteriota accounted for 51.48% of the microbial community in the FeMn@BC/PS group after 60 days, possibly converting transition products of THI into smaller molecules. This article provides a novel insight into advanced oxidative remediation of soils.

Effects of zinc ion concentrations on the performance of SBR treating livestock wastewater and analysis of microbial community.

Zinc ion (Zn2+) is a frequently occurring heavy metal in livestock wastewater. The effects of Zn2+ on the physicochemical properties and the microbial distribution of activated sludge are essential to controlling nitrogen removal performance. Nevertheless, there are raw studies on the effects of Zn2+ on nitrogen removal. This study investigated the effect of Zn2+ on the treatment performance of livestock wastewater in a sequencing batch reactor (SBR). The results indicated the low Zn2+ concentrations could improve nitrogen removal performance. However, as the Zn2+ concentration increased, the total nitrogen (TN) removal performance of the reactor gradually deteriorated. When the Zn2+ concentration was 90.00 mg/L, the TN removal efficiency was the lowest, only 2.40%. The contents of the Extracellular polymeric substance (EPS) presented a trend of first increasing and then decreasing with the increase of Zn2+ concentration, and the main reason was the decrease of protein-like and tryptophan-like. The 16SrRNA analysis indicated that Zn2+ within a specific concentration could increase the operational taxonomic units (OTUs) number, microbial richness, and diversity of microorganisms in the SBR. However, with Zn2+ concentration exceeding 10.00 mg/L, the relative abundance of denitrification functional bacteria (Dechloromonas, Nitrospira, and Thauera) decreased.

A nitric oxide responsive AIE probe for detecting the progression of osteoarthritis.

Nitric oxide (NO) is reported to be elevated in osteoarthritis (OA) both in vitro and in vivo and may be adopted to develop fluorescent probes for detecting the progression of OA. Here we report a nitric oxide responsive aggregation induced emission (AIE) probe TPE-2NHCOCH2CH2-(PEG)24-NH-Diacerein, which is derived from tetraphenylethene (TPE) modified with the hydrophilic group long poly(ethylene glycol) chain and an anti-inflammatory drug diacerein. o-Phenylenediamine within its structure can react with NO to form benzotriazole and emit fluorescence. The results show that the NO-responsive AIE probe can smartly monitor the progression of OA with the change of fluorescence intensity in vitro and in vivo. This study may provide a new development direction for early OA monitoring in clinics.

Calcium-to-phosphorus releasing ratio affects osteoinductivity and osteoconductivity of calcium phosphate bioceramics in bone tissue engineering.

Calcium phosphate (Ca-P) bioceramics, including hydroxyapatite (HA), biphasic calcium phosphate (BCP), and beta-tricalcium phosphate (ß-TCP), have been widely used in bone reconstruction. Many studies have focused on the osteoconductivity or osteoinductivity of Ca-P bioceramics, but the association between osteoconductivity and osteoinductivity is not well understood. In our study, the osteoconductivity of HA, BCP, and ß-TCP was investigated based on the osteoblastic differentiation in vitro and in situ as well as calvarial defect repair in vivo, and osteoinductivity was evaluated by using pluripotent mesenchymal stem cells (MSCs) in vitro and heterotopic ossification in muscles in vivo. Our results showed that the cell viability, alkaline phosphatase activity, and expression of osteogenesis-related genes, including osteocalcin (Ocn), bone sialoprotein (Bsp), alpha-1 type I collagen (Col1a1), and runt-related transcription factor 2 (Runx2), of osteoblasts each ranked as BCP > ß-TCP > HA, but the alkaline phosphatase activity and expression of osteogenic differentiation genes of MSCs each ranked as ß-TCP > BCP > HA. Calvarial defect implantation of Ca-P bioceramics ranked as BCP > ß-TCP ≥ HA, but intramuscular implantation ranked as ß-TCP ≥ BCP > HA in vivo. Further investigation indicated that osteoconductivity and osteoinductivity are affected by the Ca/P ratio surrounding the Ca-P bioceramics. Thus, manipulating the appropriate calcium-to-phosphorus releasing ratio is a critical factor for determining the osteoinductivity of Ca-P bioceramics in bone tissue engineering.

Which one is better for multi-territory perforator flap survival, central perforator artery or central perforator vein?

BACKGROUND: The survival of multi-territory perforator flap is associated with the position of the perforators. This study aimed to explore whether use of the central perforator artery or vein was better for flap survival. METHODS: 75 male Sprague-Dawley rats were randomly divided into three groups (n=25 per group). The flap contained the right and left iliolumbar, left posterior intercostal, and left thoracodorsal angiosomes, termed angiosomes Ⅰ to Ⅳ, respectively. The anastomosis between angiosomes Ⅱ and Ⅲ was termed choke 2. In experimental group 2, only the right iliolumbar vein and the left iliolumbar artery were preserved; in experimental group 1, only the right iliolumbar artery and the left iliolumbar vein were preserved; and in the control group, only the right iliolumbar artery and vein were preserved. On day-7 after the operation, the flap arteriography, intraluminal diameter, average microvascular density, vascular endothelial growth factor (VEGF) expression and flap survival were compared among groups. Moreover, the percentages of the angiosomes were measured. RESULTS: The dilation of the choke 2 artery was most pronounced in experimental group 2, followed by experimental group 1, and, finally, the control group (p<0.05). Similar results regarding average microvascular density, VEGF expression, and survival rate were found among the three groups. The percentages of angiosomes Ⅰ to Ⅳ were 23.1%, 23.0±3.1%, 23.0±1.9%, and 31.0±3.1%, respectively. CONCLUSIONS: Compared with the central perforator vein, the central perforator artery was more beneficial in enhancing flap survival. A multi-territory perforator flap with the central perforator artery could capture 3 angiosomes safely.

Combined effect of tetracycline and copper ion on catalase activity of microorganisms during the biological phosphorus removal.

Microbial catalase is a key enzyme that affects the activities of microorganisms, and the catalase activity is affected by pollutants in wastewater. However, the effects of mixed pollutants on catalase activity are rather complex. To reveal the effect of the mixed pollutants on catalase activity of microorganisms, the present study investigated tetracycline and copper ion as pollutants during the biological phosphorus removal. Three concentration ratios of tetracycline and copper ion and 27 different concentration gradients were designed through the direct equipartition ray and the dilution factor method. The effects of mixed pollutants on the catalase activity of microorganisms were analyzed by the nonlinear regression equation and concentration-addition model. The results showed that, with the increase of actuation duration and the pollutant concentration, the inhibitory effects on the catalase activity of microorganisms obviously increased, which indicated that the inhibitory effects are concentration-dependent and time-dependent. The concentration-addition model suggested that when the ratio was 0.297, the combined effect of mixed pollutants on the activity of microbial catalase was mainly antagonism. When the ratio is 0.894, the combined effect was mainly additivity. When the ratio was 2.676, the combined effect transformed from synergism to additivity and antagonism. The study of the combined effects of tetracycline and copper ion on the catalase activity is helpful to further study their ecotoxicological mechanisms in wastewater treatment.

Decellularized kidney scaffold alters the healing response in chronic renal failure.

Decellularized (DC) kidney scaffold shows great potential for renal recovering. Our study explored the effect of the DC kidney scaffolds treating on chronic renal failure (CRF) through grafting them on 5/6 nephrectomized (5/6 Nx) rat kidneys compared with gelatin sponges covered the incision edges. Blood urea nitrogen and angiotensin II were significantly lower in most time in scaffold-grafted groups. Remnant kidney tumor necrosis factor-α and fibroblast growth factor in scaffold-grafted groups significantly reduced in majority of time points compared with controls. But platelet-derived growth factor-BB showed a different varied tendency, first higher in scaffold groups on week 2, 4, 6, but lower on week 8, finally no difference on week 12 compared with gelatin-sponge groups. In addition, the index of glomerular sclerosis was significantly lesser in scaffold-grafted groups, and, the accumulation of collagen III and collagen IV decreased in scaffold-grafted groups on week 6, 8, 12 compared with gelatin-sponge groups. Moreover, DC scaffolds enhanced the expression of CD133 on week 2, 6, 8, 12. In conclusion, DC kidney scaffold altered the healing response after 5/6 nephrectomy and ameliorated renal injury to some degree. Therefore, DC kidney scaffold could be a promising therapeutic method on CRF.

Effects of arterial blood supply and venous return on multi-territory perforator flap survival.

This study aimed to design arterial ischemic and venous congested areas on the same multi-territory perforator flap, assessing the effects of arterial blood supply and venous return on flap survival. Totally 68 rats were randomly divided into the experimental (Exp) and control (Con) groups. In the Exp group, flaps were based on left superficial epigastric artery and right superficial epigastric vein. In the Con group, flaps were based on the left superficial epigastric artery and vein. Immediate postoperative ink-gelatin angiography, epidermal metabolite levels detection, tissue edema measurement, survival rate evaluation in half of the flaps and average microvessel density assessment were performed. Blood in the Exp group flowed through most angiosomes, but only flowed around pedicled vessels in the Con group; metabolite levels of left halves in the Con and Exp groups were comparable with those of right halves. Angiosomes with high water contents occurred in the Exp group. Survival rates of left halves in the Con and Exp groups were higher than those of right halves, and more microvessels were found in the left ventral areas of both groups compared with the right ventral area in the Exp group. These findings revealed that on the same multi-territory perforator flap, arterial blood supply, affected by venous return, is a prerequisite for flap survival.

Association between hepatitis B virus infection and risk of osteoporosis: a systematic review and meta-analysis: A protocol for systematic review.

BACKGROUND: The potential association between hepatitis B virus (HBV) infection and development of osteoporosis has drawn significant attention from clinicians and researchers in recent years due to the increasing prevalence of HBV infection. This study aims to perform a systematic review and meta-analysis of the literature to show whether HBV infection is associated with an increased risk of osteoporosis. METHODS: Case-control, cohort, and cross-sectional studies that report the incidence of osteoporosis, osteoporotic fracture, osteopenia, and bone mineral density level in populations with HBV infection will be selected. Four databases from their inception to October 2019 will be searched. All data were assessed and extracted by 2 authors independently. The Newcastle-Ottawa scale and (Agency for Healthcare Research and Quality) Agency for Healthcare Research and Quality checklist will be used to assess the quality of the selected studies. Stata 15.1 (Stata Corp, College Station, TX) will be used to conduct meta-analysis. RESULT: The results of this systemic review and meta-analysis will be submitted to a recognized journal for publication. CONCLUSION: This systemic review and meta-analysis will determine whether HBV infection is associated with an increased risk of osteoporosis. We hope this review can provide a reliable evidence. REGISTRATION: PROSPERO (registration number CRD42020140522).

A Preliminary Study of the Effects of Venous Drainage Position on Arterial Blood Supply and Venous Return within the Conjoined Flap.

BACKGROUND: Conjoined flap viability is associated with arterial blood supply and venous return. This study aimed to assess the effects of venous drainage position on arterial blood supply and venous return within the conjoined flap. METHODS: Fifty-four rats were divided randomly into three groups (n = 18 per group). In experimental group 2, only the right intercostal posterior artery and the left iliolumbar vein were maintained; meanwhile, only the right intercostal posterior artery and the left intercostal posterior vein were preserved in experimental group 1. The control group had only the right intercostal posterior artery and vein preserved. The distances between angiosomes were measured. At 7 days after surgery, flap survival was evaluated, lead oxide-gelatin flap angiography was performed, and average microvessel density was assessed by hematoxylin and eosin staining, and lactate levels were assessed. RESULTS: The distance between angiosomes I and II was the shortest, whereas angiosomes I and III were most distant (p < 0.05). At 7 days after surgery, survival rates in experimental group 2 and experimental group 1 were both 100 percent, whereas 86.5 ± 1.6 percent of controls survived. Furthermore, angiogenesis was more obvious in experimental group 2 than in experimental group 1 and controls. Moreover, lactate levels were lower in experimental group 2 (7.47 ± 0.17 mM) and experimental group 1 (8.03 ± 0.31 mM) compared with control values (9.98 ± 0.37 mM; p < 0.05). CONCLUSION: Changes in position of venous drainage might cause continuous arterial high-pressure perfusion and venous superdrainage, which improves flap survival.

Loss of thin spines and small synapses contributes to defective hippocampal function in aged mice.

Aging is a normal physiological process associated with impairments in cognitive function, including learning and memory. Here, the underlying synaptic mechanisms by which aging leads to the decline of spatial learning and memory function were investigated in 25-month-old aged mice versus 2-month-old young mice. Deficits of spatial learning and memory, as well as selective loss of thin spines, but not mushroom-type spines on apical dendrites of CA1 pyramidal cells were found in aged mice. Specifically, loss of thin spines in aged mice with memory deficits was primarily found on dendritic segments located in the Schaffer pathway, and the density of thin spines significantly correlated with spatial memory performance. The loss of thin spines was evidenced by a decrease in small synapses that express diminutive amounts of postsynaptic density protein-95 and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1. Furthermore, mushroom-type spines and GluR1-expressed large synapses were not affected in aged mice with impaired memory. Taken together, these data suggest that the selective loss of those highly plastic thin spines with sparse postsynaptic density protein-95 and GluR1 receptors may significantly contribute to cognitive deficits in aged individuals.

Spatial distributions, fractionation characteristics, and ecological risk assessment of trace elements in sediments of Chaohu Lake, a large eutrophic freshwater lake in eastern China.

The concentrations, spatial distribution, fractionation characteristics, and potential ecological risks of trace elements (Cu, Pb, Zn, Cr, Ni, and Co) in the surface sediment samples collected from 32 sites in Chaohu Lake were investigated. The improved BCR sequential extraction procedure was applied to analyze the chemical forms of trace elements in sediments. The enrichment factor (EF), sediment quality guidelines (SQGs), potential ecological risk index (PERI), and risk assessment code (RAC) were employed to evaluate the pollution levels and the potential ecological risks. The results found that the concentrations of Cu, Pb, Zn, Cr, Ni, and Co in the surface sediments were 78.59, 36.91, 161.84, 98.87, 38.92, and 10.09 mg kg-1, respectively. The lower concentrations of Cu, Pb, Zn, Cr, and Ni were almost found in the middle part of the lake, while Co increased from the western toward the eastern parts of the lake. Cr, Ni, Co, and Zn predominantly existed in the residual fractions, with the average values of 76.35, 59.22, 45.60, and 44.30%, respectively. Cu and Pb were mainly combined with Fe/Mn oxides in reducible fraction, with the average values of 66.4 and 69.1%, respectively. The pollution levels were different among the selected elements. Cu had the highest potential ecological risk, while Cr had the lowest potential ecological risk.

Repair of Fingertip Defect Using an Anterograde Pedicle Flap Based on the Dorsal Perforator.

BACKGROUND: The purposes of this article are to introduce and assess the results of a long-term follow-up of using anterograde pedicle flap based on the dorsal branches of proper digital neurovascular bundles from the dorsum of the middle phalanx for the fingertip defect. METHODS: Between February 2011 and December 2012, 31 patients underwent reconstruction of fingertip defects using a homodigital flap based on the dorsal perforator in the middle phalanx. The defect size ranged from 1.3 cm × 1.5 cm to 2.4 cm × 3.0 cm. During surgery, the flap was designed on the dorsal middle phalangeal region. The pedicle was a neurovascular bundle consisting of an artery, vein, and sensory nerve; the rotation of pedicle was <90 degrees. RESULTS: The clinical results were satisfactory after 3 to 9 months of follow-up. The flaps were considered cosmetically acceptable by both patients and doctors. The sensory recovery was excellent, 2-point discrimination was 4.96 ± 1.47 mm, and the recovery of range of motion of the interphalangeal joints was very good. CONCLUSIONS: The anterograde island flap based on the dorsal branches of proper digital neurovascular bundles is an ideal aesthetic reconstruction method for fingertip defect. A 90-degree rotated island pedicle flap was very versatile, easy to design, and had good survival. This technique is simple with less damage to the donor site, without sacrificing the branch of the digital artery and nerve. The reliable source of blood supply and satisfactory recovery of sensation can be achieved without affecting the interphalangeal joint activity.

Effects of Venous Superdrainage and Arterial Supercharging on Dorsal Perforator Flap in a Rat Model.

OBJECTIVE: To comparatively assess the effects of venous superdrainage and arterial supercharging on dorsal perforator flap survival. MATERIALS AND METHODS: Sixty male Sprague-Dawley rats (450-550g) were randomly divided into three groups (n = 20), including control group (Control) and experimental groups A (venous superdrainage, Exp. A) and B (arterial supercharging, Exp. B). At postoperative day 7, survival areas of the flaps were evaluated and all animals underwent angiography. Laser Doppler was used to evaluate flap perfusion from 0h to 7days after surgery. Histology with hematoxylin and eosin staining was used to count microvessels. Tissue of "Choke vessels"was excised for quantification of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) by western blot assay at 6h and 7days after surgery. RESULTS: In the Exp. A group, almost all flaps survived (98.2±1.6%); in the Exp. B and control group, survival areas accounted for 78.8±8.5% and 60.3±7.8%, respectively (P <0.001). In addition, Exp. A animals showed improved anastomosis of choke vessels 2 compared with the Exp. B and Control groups. Furthermore, flap blood flow and partial pressure of oxygen in the Exp. A group were significantly higher compared with values obtained for the Exp. B and Control groups, from 6 hours to 7 days after surgery. More microvessels were found in the Exp. A group (11.65±1.33) than in Exp. B (9.25±0.34) and control (7.25±0.91) animals on POD 7. The relative expression level of HIF-1α and VEGF were significant at 6h and 7days after surgery. CONCLUSIONS: Venous superdrainage in rat dorsal perforator flap is more effective than arterial supercharging in promoting flap survival, and could effectively alter hemodynamics in the microcirculation and stimulate blood vessel formation.