Functional UiO-66 for highly selective adsorption of N-nitrosodipropylamine: adsorption performance and mechanisms.

N-Nitrosodipropylamine (NDPA) is a class of nitrogenous disinfection by-products (N-DBPs) with high toxicity. Although NDPA present in water bodies is at relatively low concentrations, the potential risk is high due to its high toxicity and bioaccumulation. Metal-organic frameworks (MOFs), a new type of porous material with remarkable functionality, have shown great performance in a wide variety of applications in adsorption. This is the first study investigating the adsorption of MOFs on NDPA. Herein, UiO-66 with -NH2 and imidazolium functional groups were synthesized by modifying UiO-66 after amination. Adsorption kinetics and isotherm models were used to compare the adsorption properties of the two materials for low-concentration NDPA in water. The results showed that the behavior of all the adsorbents was consistent with the Langmuir model and the pseudo-second-order model and that the adsorption was homogeneous chemisorption. The structures of the nanoparticles were characterized by FTIR, zeta potential, XRD, SEM and BET measurements. Based on the characteristics, four adsorption mechanisms, namely electron conjugation, coordination reaction, anion-π interaction, and van der Waals forces, were simultaneously involved in the adsorption. The influencing factor experiment revealed that the adsorption of UiO-66-NH2 and (I-)Meim-UiO-66 involved hydrogen bonding and electrostatic interactions, respectively.

Mechanism and anti-corrosion measures of carbon dioxide corrosion in CCUS: A review.

Carbon capture, utilization, and storage (CCUS) technology is widely recognized as a key solution for mitigating global climate change. Consequently, it has received significant attention from countries worldwide. However, carbon dioxide corrosion poses a significant challenge to CCUS and represents a bottleneck to the large-scale development and application of this technology. To mitigate this issue, this review starts with a discussion of corrosion problems in CCUS. Later, the fundamentals of the carbon dioxide corrosion mechanism are introduced. Then, the influences of various factors that affect the corrosion are highlighted, such as water content, pH, flow rate, etc. Afterward, we summarize the commonly used methods for corrosion protection, with a particular focus on inhibitor, given their eco-friendly and effective nature. Lastly, challenges and prospects are discussed to motivate future studies on developing novel, high-performance green inhibitor and studying the corresponding protection mechanisms, hoping to make some contributions to carbon emission reduction.

Efficient treatment of aged landfill leachate containing high ammonia nitrogen concentration using dynamic wave stripping: Insights into influencing factors and kinetic mechanism.

Aged landfill leachate is challenging to treat owing to its extremely high ammonia concentration and poor biodegradability. We constructed pilot-scale dynamic wave stripping equipment to separate ammonia from landfill leachate and achieved excellent results. To further expand the usage of pilot-scale equipment in actual water treatment process and implement it in a sewage plant, we established the mass transfer kinetic physics and mathematical model of the dynamic wave stripping process based on the surface renewal theory and the traditional stripping method. The surface renewal theory and the traditional stripping method are employed to analyze the mechanism of various experimental parameters affecting the stripping process, predict the stripping effect of the equipment under different conditions, and verify the calculation results of the model using the kinetic fitting results of the experimental data. These calculation results of the model indicate that the mass transfer kinetic coefficients of ammonia stripping at 20 °C, 25 °C, and 30 °C are 85.62 min, 75.34 min, and 65.88 min, respectively, when the gas-liquid ratio is 129. When the gas-liquid ratios are 62, 129, and 163 at 25 °C, the mass transfer kinetic coefficients of ammonia stripping are 102.61 min, 75.34 min, and 61.43 min, respectively. With increasing temperature and gas-liquid ratio, the particle size and number of bubbles in the wave tube of the stripping equipment gradually decrease and the mass transfer efficiency of free ammonia between the gas and liquid phases improves, enhancing the stripping efficiency of ammonia nitrogen.

Dose-effect research using nanopatch to deliver siRNA in the inhibition of HPV gene expression / 生物医学工程学杂志

Hela is the cell line of adenocarcinoma of the uterine cervix, and human papillomavirus (HPV) 18 shows positive. We delivered siRNA with target specifically to HPV18 E7 mRNA into nude mice Hela tumor xenografts by nanopatch to inhibit the HPV gene expression, and further to study the superiority, the best action time and concentration of siRNA of using nanopatch to transfer siRNA in vivo. We designed siRNA that target specifically to HPV18 E7 mRNA (siE7) and checked the effect of siE7 in vitro. Tumor xenografts were transfected with siE7 and GenEscort III by nanopatch. Expression of HPV18 E7 mRNA and protein were detected 0 hours, 24 hours, 48 hours, 72 hours after transfection with PT-PCR and Western blot, and the best action time was analyzed using nanopatch to thansfect siRNA in vivo. We transfected GenEscort III and siE7 of Different concentration into tumor xenografts respectively by nanopatch and intraperitoneal injection. Expression of HPV18 E7 mRNA and protein was detected 72 hours after transfection by PT-PCR and Western blot, to analyze the best action concentration of siRNA and the superiority of using nanopatch to thansfect siRNA in vivo. The results proved that SiE7was efficient to inhibit expression of HPV18 E7 mRNA and to advance Hela apoptosis in vitro. SiE7 transfected by nanopatch into xenografts could inhibit effectively expression of HPV18 E7 mRNA and protein. The best action time and concentration of siRNA of using nanopatch to thansfect siRNA in vivo are 72 hour post-transfection and 2 micromol/L siE7. To compare intraperitoneal injection in delivering siRNA in vivo, the effect of nanopatch is very predominant. It can be well concluded that Nanopatch can effectively transfer siRNA in vivo, which can effectively inhibit the HPV gene expression.

Ceramide mediates inhibition of the AKT/eNOS signaling pathway by palmitate in human vascular endothelial cells.

BACKGROUND: In metabolic syndrome, down-regulation of the insulin signaling leads to insulin-regulated metabolism and cardiovascular dyfunctions. Free fatty acids (FFAs) in the circulation are increased in this disorder and inhibit insulin signaling. Lipid oversupply contributes to the development of insulin resistance, likely by promoting the accumulation of lipid metabolites capable of inhibiting signal transduction. MATERIAL/METHODS: This study was designed to examine the effects of FFAs and their metabolites on the insulin signaling pathway that leads to the activation of endothelial nitric oxide synthase (eNOS) and increase in nitric oxide (NO) production in endothelial cells. RESULTS: Here we demonstrate that exposing human umbilical vein endothelial cells (HUVECs) to palmitate inhibits activation of Akt/eNOS signal pathway by insulin, and subsequently insulin-stimulated NO generation. Palmitate concomitantly induced the accumulation of ceramide, a product of acyl-CoA that has been shown to accumulate in insulin-resistant tissues and to inhibit insulin signaling. Preventing de novo ceramide synthesis abolished the antagonistic effect of palmitate toward the Akt/ eNOS pathway. Moreover, inducing ceramide buildup augmented the inhibitory effect of palmitate. CONCLUSIONS: Taken together, we have demonstrated that palmitic acid induces accumulation of ceramide, which appears to mediate palmitic acid's inhibitory effects on the Akt/eNOS pathway, leading to a significant decrease in NO generation. Therefore, ceramide is a necessary and sufficient intermediate mediating the inhibition of the AKT/eNOS signaling pathway by palmitate in endothelial cells.

Surface modification of biodegradable polymer/TCP scaffolds and related research / 生物医学工程学杂志

Under laboratory condition, the compound materials of Poly (DL-lactic-co-glycolic acid)/Tricalcium phosphate [PLGA/TCP(L), with component ratio of 7:3] were fabricated by combining the thermally induced phase separation (TIPS) with solvent-casting particulate-leaching (SCPL) approach. On the other hand, rapid prototyping (RP) technique manufactured PLGA/TCP scaffolds [PLGA/TCP(RP)] were obtained. These two kinds of carriers were coated with collagen type I (Col I). The extracted bovine bone morphogenetic protein (bBMP) was loaded into carriers to establish biomimetic synthetic bones. PLGA/TCP(L) scaffolds, demineralized bone matrices (DBM) of bovine cancellous bone, PLGA/TCP(L) scaffolds, biomimetic synthetic bones and OsteoSet bone graft substitutes were investigated. Scanning electron microscopy revealed that the microarchitecture of PLGA/TCP(RP) scaffolds was much better than that of PLGA/TCP(L) scaffolds. The diameter of macropore of PLGA/TCP(RP) scaffold was 350 microm. The porosities of PLGA/ TCP(L) scaffolds, DBM, PLGA/TCP(RP) scaffolds and OsteoSet bone graft substitutes were 21.5%, 70.4%, 58.6% and 0%, respectively (P<0.01). Modification of PLGA/TCP scaffolds with collagen type I [PLGA/TCP(L)-Col I and PLGA/TCP(RP)-Col I] essentially increased the affinity of the carriers to bBMP. Among these synthetic materials, PLGA/TCP(RP)-Col I-bBMP composite is promising as a novel bone graft substitute due to its advanced fabrication technique, good tri-dimensional microarchitecture and ideal components.

Repair of the radial defect of rabbit with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate the effects of repairing rabbit radial defects with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine bone morphogenetic protein (bBMP), and find new carriers for growth factors.</p><p><b>METHODS</b>Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with and without bovine BMP were used to repair the 15 mm radial defect in rabbit. Then the results of radiography, histology, scaffolds degrade rates and bone mineral density (BMD) were appraised to examine the effects at the 12th week.</p><p><b>RESULTS</b>At the 12th week postoperatively, all defects treated with bBMP were radiographically repaired. No radius implanted polyester/tricalcium phosphate scaffolds without bBMP showed radiographic and histological union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at the 12th week, indicating that remodeling of regenerated bone was complete in different degree. Of the three experimental groups, the bony regeneration and remodeling of callus in poly lactide-co-glycolide/tricalcium phosphate (PLGA/TCP) group was the best. The BMD values were beyond 70% of normal value at the 12th week while the PLGA/TCP scaffolds group was the highest, and no abnormalities were observed in the surrounding soft tissue in all groups.</p><p><b>CONCLUSIONS</b>Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair a 15 mm radial defect of rabbit. As for the results, the PLGA/TCP scaffold is ideal and better than poly L-lactide-co-D, L-lactide (PDLLA/TCP) scaffold, but the ploy L-lactic acid (PLLA/TCP) is not so good for its low degradation rates.</p>

[Effects of simvastatin on TGF-beta system of diabetic rat kidneys].

OBJECTIVE: To investigate the effects and mechanism of renal benefit of simvastatin on diabetic rat kidneys. METHODS: Twenty STZ-induced SD rats and 10 normal rats were assigned to diabetic rat (DM) group, simvastatin [ 4 mg/( kg x d) ] treatment (S) group and normal control (C) group. Immunohistochemistry, RT-PCR and western-blot were employed to examine the changes of the mRNA and protein expression of TGF-beta1 and Tbeta II R in the kidneys of the rats. RESULTS: Compared with the normal control group, both the mRNA and protein expression of TGF-beta1 and Tbeta II R in the diabetic rat group and treatment group were significantly increased (P < 0.05). Compared with the diabetic rat group, simvastatin could markedly decrease the mRNA and protein expression of TGF-beta1 and Tbeta II R (P < 0.05). CONCLUSION: Simvastatim may play a protective role in the diabetic kidneys by down-regulating TGF-beta1 and Tbeta II R and inhibiting the TGF-beta signal pathway.

Effects of simvastatin on TGF-beta system of diabetic rat kidneys / 中南大学学报(医学版)

OBJECTIVE@#To investigate the effects and mechanism of renal benefit of simvastatin on diabetic rat kidneys.@*METHODS@#Twenty STZ-induced SD rats and 10 normal rats were assigned to diabetic rat (DM) group, simvastatin [ 4 mg/( kg x d) ] treatment (S) group and normal control (C) group. Immunohistochemistry, RT-PCR and western-blot were employed to examine the changes of the mRNA and protein expression of TGF-beta1 and Tbeta II R in the kidneys of the rats.@*RESULTS@#Compared with the normal control group, both the mRNA and protein expression of TGF-beta1 and Tbeta II R in the diabetic rat group and treatment group were significantly increased (P < 0.05). Compared with the diabetic rat group, simvastatin could markedly decrease the mRNA and protein expression of TGF-beta1 and Tbeta II R (P < 0.05).@*CONCLUSION@#Simvastatim may play a protective role in the diabetic kidneys by down-regulating TGF-beta1 and Tbeta II R and inhibiting the TGF-beta signal pathway.

Repair of the radial defect of rabbit by polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the repairing effect of the rabbits radial defects of by polyester/tricalcium phosphate scaffolds prepared by rapid forming technology loaded with bovine BMP, and find a new carrier for growth factor.</p><p><b>METHODS</b>Polyester/Tricalcium phosphate scaffolds prepared by rapid prototyping (RP) technology loaded with and without bovine BMP were used to repair the 15 mm radial defect of rabbit. Then results of radiography, histology, scaffolds degrade rates and bone density were appraised to examine the repairing effects of the scaffolds at 12 weeks.</p><p><b>RESULTS</b>At 12 weeks, all defects treated with bBMP were radiographically repaired. No radii implanted polyester/tricalcium phosphate scaffolds alone showed radiographic and historical union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at 12 weeks, indicating that remodeling of regenerated bone almost completed, the scaffolds degradation rates were different by 12 weeks, and no abnormalities were observed in the surrounding soft tissue in all groups.</p><p><b>CONCLUSION</b>Polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair the rabbits radical defects. As for the effects, the poly (L-lactic-co-glycolide)/tricalcium phosphate (PLGA/TCP) scaffold are ideal and better than poly (L-lacide-co-D, L-lactide)/tricalcium phosphate (PDLLA/TCP) scaffold, but the poly (L-lactic acid)/tricalcium phosphate (PLLA/TCP) is not so good for its low degradation rates.</p>

Observation of the repair of rabbit radial defect with poly (L-lactic acid)/tricalcium phosphate scaffolds and degradation rate / 中国组织工程研究

BACKGROUND: Scaffolds are an important part in bone tissue engineering. However, no perfect scaffolds have been developed for bone tissue engineering yet.OBJECTIVE: To evaluate the repair of rabbit radial defects by poly (L-lactic acid)/tricalcium phosphate(PLLA/TCP) scaffolds prepared by rapid prototyping(RP) technology so as to find a new carrier for growth factors.DESIGN: A completely randomized controlled study was conducted. SETTING: Orthopaedic institute of a military medical university.MATERIALS: The study was conducted in the General Orthopedic Institute,Fourth Military Medical University of Chinese PLA, from May 2001 to February 2002. Twenty clean New Zealand rabbits with body mass of(2.5 ±0. 5) kg for this study were obtained from the Experiment Animal Center of Fourth Military Medical University of Chinese PLA. The animals were divided into experiment group and control group with 10 rabbits in each group.INTERVETIONS: PLLA/TCP scaffolds prepared by RP technology and loaded with or without bovine bone morphogenetic protein (BMP) were used to repair the rabbit radial defects of 15 mm.MAIN OUTCOME MEASURES: Main outcomes: ① microscopic observation results of transplanted materials of the two groups; ② degradation rate of scaffolds. Secondary outcomes: ① gross observation; ② radiographic results; ③ bone density.RESULTS: At week 12, bone defect healing in experiment group was good. X-ray examination showed continuous bone callus and partial molding of different degrees. Degradation rate of scaffolds was 39.6%, and bone density in the defected part reached 70% of the normal level. All the indexes of experiment group were superior to those of control group, and no healing was found in the defected area in control group.CONCLUSION: PLLA/TCP scaffolds prepared by RP technology and loaded with bovine BMP can repair radial defects of 15mm in rabbits.

Effect of type I collagen on the adhesion, proliferation, and osteoblastic gene expression of bone marrow-derived mesenchymal stem cells / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the effects of porous poly lactide-co-glycolide (PLGA) modified by type I collagen on the adhesion, proliferation, and differentiation of rabbit marrow-derived mesenchymal stem cells (MSCs).</p><p><b>METHODS</b>The third generation MSCs isolated from mature rabbits by density gradient centrifugation were cultured at different initial concentrations on 0.3 cm x 1.2 cm x 2.0 cm 3-D porous PLGA coated by type I collagen in RPMI 1640 containing 10% fetal calf serum, while cultured on PLGA without type I collagen as control. The cells adhesive and proliferative behavior at 7, 14, and 21 days after inoculation was assessed by determining the incorporation rate of [(3)H]-TdR. In order to examine MSCs differentiation, the expression of osteoblasts marker genes, osteocalcin (OCN), alkaline phosphatase (ALP), osteopontin (OPN) mRNA, were evaluated by reverse transcription-polymerase chain reaction (RT-PCR), and further more, the cell morphology at 21 days was also observed by scanning electron microscope (SEM).</p><p><b>RESULTS</b>Type I collagen promoted cell adhesion on PLGA. The valve was significantly higher than controls (6 h, 2144 cpm+/-141 cpm vs. 1797 cpm+/-118 cpm, P=0.017; 8 h, 2311 cpm+/-113 cpm vs. 1891 cpm+/-103 cpm, P=0.01). The cells which cultured on PLGA coated with type I collagen showed significantly higher cell proliferation than controls on the 7 th day (1021 cpm+/-159 cpm vs. 451 cpm+/-67 cpm, P=0.002), the 14th day (1472 cpm+/-82 cpm vs. 583 cpm+/-67 cpm, P<0.001) and 21 th day (1728 cpm+/-78 cpm vs. 632 cpm+/-55 cpm, P<0.001). Osteoblasts markers, OCN, ALP, OPN mRNA, were all detected on PLGA coated by type I collagen on the 21 th day, but OCN, OPN mRNA could not be found in controls. Spindle and polygonal cells well distributed on the polymer coated by type I collagen while cylindric or round cells in controls.</p><p><b>CONCLUSIONS</b>Type I collagen is effective in promoting the adhesion, proliferation and differentiation of MSCs on PLGA.</p>

Rapid manufacturing of degradable porous polymer bone scaffold / 生物医学工程学杂志

Making bone scaffold through tissue engineering method presents a new choice for both the patients and the doctors of orthopaedics. The biodegradable polymer PLA is chosen to make porous fundus scaffold jetting through special designed nozzle on multi-functional rapid prototyping machine controlled by computer according to the CT data CAD model. The scaffold is then chemically aggregated to compound with collagen-hydroxyapatite, and the ideal bone repair material is obtained. Animal experiment has indicated the correctness of this conclusion.