Bubble-propelled micromotors based on hierarchical MnO2 wrapped carbon nanotube aggregates for dynamic removal of pollutants

Water pollution is currently an urgent public health and environmental issue. Bubble-propelled micromotors might offer an effective approach for dealing with environmental contamination. Herein, we present the synthesis of multi-walled carbon nanotube (MWCNT)/manganese dioxide (MnO₂) micromotors based on MWCNT aggregates as microscale templates by a simple one-step hydrothermal procedure. The morphology, composition, and structure of the obtained MWCNT/MnO₂ micromotors were characterized in detail. The MnO₂ nanoflakes formed a catalytic layer on the MWCNT backbone, which promoted effective bubble evolution and propulsion at remarkable speeds of 359.31 μm s⁻¹. The bubble velocity could be modulated based on the loading of MnO₂ nanoflakes. The rapid movement of these MWCNT/MnO₂ catalytic micromotors resulted in a highly efficient moving adsorption platform, which considerably enhanced the effectiveness of water purification. Dynamic adsorption of organic dyes by the micromotors increased the degradation rate to approximately 4.8 times as high as that of their corresponding static counterparts. The adsorption isotherms and adsorption kinetics were also explored. The adsorption mechanism was well fitted by the Langmuir model, following pseudo-second-order kinetics. Thus, chemisorption of Congo red at the heterogeneous MnO₂ wrapped microimotor surface was the rate determining step. The high propulsion speed and remarkable decontamination efficiency of the MWCNT/MnO₂ micromotors indicate potential for environmental contamination applications.

Water pollution is currently an urgent public health and environmental issue.     

Synergetic treatment of dye contaminated wastewater using microparticles functionalized with carbon nanotubes/titanium dioxide nanocomposites

The highly efficient treatment of azo dye contaminated wastewater from the textile industry is an important but challenging problem. Herein, polydimethylsiloxane (PDMS) microparticles, incorporating multiple-walled carbon nanotubes/titanium dioxide (MWCNTs/TiO₂) nanocomposites, were successfully synthesized to treat wastewater containing Rhodamine B (RhB) dyes in a synergetic approach, by combining sorption and photocatalytic degradation. The surfactant wrapping sol–gel method was applied to synthesize MWCNTs/TiO₂ nanocomposites with TiO₂ nanoparticles evenly distributed on the surface of the MWCNTs. The PDMS microparticles were fabricated with an oil-in-water (O/W) single emulsion template, using needle-based microfluidic devices. MWCNTs/TiO₂ nanocomposites (at a weight ratio of 1%, and 2%, respectively) were mixed with the PDMS precursor as the dispersed phase, and an aqueous solution of polyvinyl alcohol (PVA) was used as the continuous phase. Highly monodispersed microparticles, with average diameters of 692.7 μm (Coefficient of Variation, CV = 0.74%) and 678.3 μm (CV = 1.04%), were formed at an applied flow rate of the dispersed and continuous phase of 30 and 200 μL min⁻¹, respectively. The fabricated hybrid microparticles were employed for the treatment of RhB, involving a dark equilibrium for 5 hours and UV irradiation for 3 hours. The experimental conditions of applied PDMS type, mass loading amount, treatment duration, photodegradation kinetics, initial concentration of pollutants and environmental pH values were investigated in this work. The PDMS microparticles with 2 wt% MWCNTs/TiO₂ nanocomposites can exhibit a removal efficiency of 85%. Remarkably, an efficiency of 70% can be retained after the microparticles have been recycled and reused for 3 cycles. The PDMS–MWCNTs/TiO₂ microparticles possess a superior performance over conventional treatment approaches for dye contaminated wastewater, especially in recyclability and the prevention of secondary pollution. This work provides a feasible and eco-friendly route for developing an efficient and low-cost microfluidic method for treating complicated water environmental systems.

PDMS–MWCNTs/TiO₂ microparticles made by microfluidics can achieve 85% removal efficiency of RhB pollutant in wastewater via synergetic treatment.     

联合应用压力手套及压力垫治疗手背烧伤后瘢痕的疗效观察

目的：观察联合应用压力手套和压力垫对手背侧烧伤后瘢痕增生的预防和治疗作用。方法：对58只烧伤后愈合患手分别采用单纯压力手套和联合应用定制压力手套及压力垫进行干预,用Sawada评分方法对两组治疗前、治疗3个月及治疗6个月手背瘢痕色泽、厚度、硬度及敏感度进行定量评分,比较其治疗差异。结果：联合治疗组在治疗6个月后效果优于单纯治疗组,具有统计学差异（P〈0．05）。结论：联合治疗组较单纯治疗组更有效控制瘢痕增生及因瘢痕增生引起的继发畸形,外观改善明显。     

Hyperbaric oxygen treatment prevents nitric oxide‐induced apoptosis in articular cartilage injury via enhancement of the expression of heat shock protein 70

Heat shock proteins (HSPs), inflammatory cytokines, nitric oxide (NO), and localized hypoxia‐induced apoptosis are thought to be correlated to the degree of cartilage injury. We investigated the effect of hyperbaric oxygen (HBO) on (1) interleukin‐1β (IL‐1β)‐induced NO production and apoptosis of rabbit chondrocytes and (2) healing of articular cartilage defects. For the in vitro study, RT‐PCR and Western blotting were performed to detect mRNA and protein expressions of HSP70, inducible NO synthase (iNOS), and caspase 3 in IL‐1β‐treated chondrocytes. To clarify that the HSP70 was necessary for anti‐iNOS and anti‐apoptotic activity by HBO, we treated the cells with an HSP70 inhibitor, KNK437. For the in vivo study, cartilage defects were created in rabbits. The HBO group was exposed to 100% oxygen at 2.5 ATA for 1.5 h a day for 10 weeks. The control group was exposed to normal air. After sacrifice, specimen sections were sent for examination using a scoring system. Immunohistochemical analyses were performed to detect the expressions of iNOS, HSP70, and caspase 3. Our results suggested that HBO upregulated the mRNA and protein expressions of HSP70 and suppressed those of iNOS and caspase 3 in chondrocytes. KNK437 inhibited the HBO‐induced downregulation of iNOS and casapase 3 activities. The histological scores showed that HBO markedly enhanced cartilage repair. Immunohistostaining showed that HBO enhanced HSP70 expression and suppressed iNOS and caspase 3 expressions in chondrocytes. Accordingly, HBO treatment prevents NO‐induced apoptosis in articular cartilage injury via enhancement of the expression of heat shock protein 70. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 376–384, 2013     

Bleeding renal angiomyolipoma presenting as duodenal obstruction

We report a case of a 60-year-old woman who had a delayed presentation of duodenal obstruction as a result of a bleeding right renal angiomyolipoma (AML) with retroperitoneal hematoma. Her duodenal obstruction did not improve upon conservative management, and a computed tomography (CT)-guided drainage of the retroperitoneal hematoma was subsequently performed. Post-intervention, CT scan confirmed hematoma resolution, and she was able to resume normal diet afterwards. We present this first reported case of a bleeding renal AML with retroperitoneal hematoma causing duodenal obstruction and discuss on the management of such condition.     

Does Preoperative 25-Hydroxyvitamin D Status Significantly Affect the Calcium Kinetics after Total Thyroidectomy?

Background

Although previous studies have suggested that low preoperative 25-hydroxyvitamin D (25-OHD) is a risk factor for hypocalcemia after total thyroidectomy, the impact of preoperative 25-OHD on calcium (Ca)/parathyroid hormone (PTH) kinetics in the immediate postoperative period remains unclear. The study compared the postoperative Ca/PTH kinetics between different preoperative 25-OHD levels.

Patients

A total of 281 patients who underwent a total thyroidectomy were analyzed. Serum Ca was measured preoperatively within 1 h after surgery (Ca-D0) and on the following morning (Ca-D1). Preoperative 25-OHD was also measured after overnight fasting while postoperative PTH was checked at skin closure on day 0 (PTH-D0) and on the following morning on day 1 (PTH-D1). The Ca/PTH kinetics were compared between three groups (group I: preoperative 25-OHD < 10 ng/mL; group II: 25-OHD = 10–20 ng/mL; group III: 25-OHD > 20 ng/mL).

Results

Group I had significantly lower preoperative Ca (p = 0.016) and Ca-D0 (p = 0.036) but higher PTH-D1 (p = 0.015) than groups II and III. PTH-D0, Ca-D1, and the rate of clinically significant hypocalcemia were similar in the three groups. Group I had a significantly smaller Ca drop (?0.02 vs. 0.01 and 0.02 mmol/L, p = 0.011) and a tendency for a significantly smaller PTH drop (0.4 vs. 0.5 and 1.0 pmol/L, p = 0.073) than groups II and III. PTH-D1 (OR = 1.550) and 25-OHD (OR = 0.958) were independent factors for Ca drop from day 0 to day 1.

Conclusions

Although group I began with lower serum Ca, those patients tended to have a greater PTH response to Ca drop and so preoperative 25-OHD did not significantly affect the overall Ca kinetics from preoperative to day 1.     

Effect of Diabetes on Outcomes in Patients Undergoing Emergent Cholecystectomy for Acute Cholecystitis

Background

The purpose of the present study was to determine the prevalence of diabetes and its effect on surgical outcomes in patients undergoing emergent, in-patient cholecystectomy for acute cholecystitis. Some 8.3 % of the U.S. population has diabetes and this number is projected to rise to 21–33 % by 2050. Diabetes is considered to be associated with a higher incidence of acute cholecystitis; however, its impact on outcomes is unknown.

Methods

The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify all patients with acute cholecystitis who underwent emergent in-patient cholecystectomy from 2004 to 2010. The study population was divided into two groups: diabetics and non-diabetics. Diabetics were further subdivided into those taking oral medication and those on insulin. Demographics, co-morbidities, and wound classification were compared with univariate analysis, and 30-day outcomes were compared with univariate and multivariate analyses.

Results

A total of 5,460 patients met the inclusion criteria. Of these 770 (14.10 %) had a diagnosis of diabetes. Mortality was higher for diabetics than for non-diabetics [4.4 vs 1.4 %, adjusted odds ratio (AOR) (95 % CI): 1.79 (1.09, 2.94), adj-p = 0.022]. Preoperative perforation rates were 25.1 and 13.0 %, respectively [AOR (95 % CI): 1.34 (1.09, 1.65), adj-p = 0.005]. The adjusted risk of cardiovascular events and renal failure was significantly higher for diabetics. Insulin treatment, but not oral medication, was associated with a significant increase in mortality, preoperative perforation, superficial surgical site infection, septic shock, cardiovascular incidents, and renal insufficiency.

Conclusions

In patients undergoing cholecystectomy for acute cholecystitis, diabetes increases the risk of mortality, cardiovascular events, and renal failure. Insulin-treated diabetics have more co-morbidities and poorer outcomes.