A Novel Photosynthetic Biohybrid System for Microenvironment Regulation of Diabetes Retinopathy through Continuous Oxygen Supply and Nanozyme Cascade Reaction

According to International Diabetes Federation Diabetes Atlas statistics, diabetic retinopathy (DR) is the leading cause of vision loss in blinding diseases. The underlying cause of retinal vasculopathy progression in diabetic patients is hyperglycemia and hypoxia features in microvascular region. Hence, cyanobacteria are used as carriers to load both gold nanoparticles (Au NPs) with glucose oxidase-like activity and iridium nanoparticles (Ir NPs) with catalase-like activity, respectively (Cyano@Au@Ir). The Au NPs nanozyme first degrades glucose into hydrogen peroxide, which is further decomposed into H₂O and O₂ by the Ir NPs to complete the cascade hypoglycemic reaction. Based on the unique light transmittance of eyeball and the accumulation of light in the retinal area, the sustainable O₂ production by Cyano greatly alleviates the hypoxia of microenvironment, leading to the decrease of angiogenic growth factor and hypoxia-inducible factor expressions. Simultaneously, the highly expressed peroxide in the DR microenvironment can also be eliminated by Ir NPs for anti-inflammatory property. Furthermore, it is demonstrated in DR animal model that Cyano@Au@Ir significantly reduces neovascular progression and vascular leakage. This novel treatment mode fundamentally degrades blood glucose, continuously supplies O₂, and scavenges free radicals for comprehensive microenvironment regulation, providing inspirations for solving fundus complications of DR.     

Derivation of generic optimal reference temperature profiles for steady-state exothermic jacketed tubular reactors

Despite the existence of advanced controllers for jacketed tubular reactors, generic optimal steady-state reference temperature profiles are rather scarce. In this paper, optimal (infinite dimensional) temperature profiles are derived by exploiting a combination of analytical and numerical optimal control techniques for two cost criteria which both involve a trade-off between a conversion and an energy cost. Hereby, the following results are obtained: (i) a more complex model which also incorporates heat transfer, yields more valuable references than a simple model which only takes the reaction into account, (ii) the analytical approach allows to extract generic features in the reference profiles, enhancing the robustness against model mismatch, and (iii) the performance loss due to practical implementation hardware, i.e., the availability of only a finite number of isothermal jacket elements, is quantified.     

Ageing of EUROBITUM bituminised radioactive waste: An ATR-FTIR spectroscopy study

The extent of the physico-chemical processes of concern in the study of the acceptability of Eurobitum bituminised radioactive waste for underground disposal (water uptake by hygroscopic NaNO₃ - swelling - pressure build-up - NaNO₃ leaching) will depend on the degree of ageing of the bituminous matrix. In the work reported here, the ageing behaviour was studied by comparing the characteristics of 25 years old radioactive Eurobitum with those of 25 years old non-radioactive Eurobitum samples that were heated or gamma-irradiated in the presence or absence of oxygen. Chemical changes in the bitumen structure were followed in the mid-infrared region with Attenuated Total Reflectance Fourier Transform InfraRed Spectroscopy (ATR-FTIR) by measuring the evolution of the band heights at 1700 cm⁻¹ (CO functional groups) and 1600 cm⁻¹ (CC double bonds). Needle penetration depths and ring and ball softening points were determined for some samples. Oxidation of bitumen in the presence of oxygen results in a distinct increase of both the number of CO and CC functionalities, with a positive linear relationship existing between the two groups. The production of CO functional groups seems to promote the generation of CC double bonds. Heating at 130 °C is much more efficient than gamma irradiation at low to moderate dose rates (20-140 Gy/h) to oxidise the bitumen. As the oxygen concentration decreases, for instance by diffusion limitation deeper inside the bitumen, the number of CO and CC functionalities formed per unit of time decreases. A similar behaviour was observed for 25 years old radioactive Eurobitum. In absence of oxygen, gamma irradiation still results in a small increase of the number of CO functional groups, probably by oxygen still adsorbed on the bitumen, and in a relatively higher amount of CC double bonds. The surface layer (<5 cm) of 25 years old radioactive Eurobitum was heavily oxidised. The material had become very hard and brittle, and was full of small fissures. Due to these fissures, radio-oxidation processes took also place deeper inside the waste. The consequences of these observations for the long-term behaviour of Eurobitum in underground disposal conditions are discussed.     

Evaluation of a rapid physical-chemical method for the determination of extant soluble COD

Characterization of total chemical oxygen demand (COD) in wastewater is critical for accurate modeling of constituent biotransformation steps. We evaluated the accuracy and precision of a commonly used soluble COD determination technique (coagulation using ZnSO4 at pH 10.5) in relation to three other physical-chemical separation techniques: destabilization with a non-hydrolyzing trivalent cation (LaCl3), sequential filtration, and ultracentrifugation. Samples of deionized water and domestic wastewater were spiked with aliquots of synthetic soluble COD and recoveries using the different separation methods were compared. Although mechanisms of coagulation using LaCl3 and ZnSO4 are different, the mean COD recoveries using these methods were in close agreement. Further, sorption of soluble COD onto zinc hydroxide precipitate flocs appeared to be negligible. The two coagulation methods yielded statistically different (p = 0.05) soluble COD values when applied to nine independent wastewater samples (obtained on nine different days). but the difference was less than 10%. The COD quantified by the coagulation techniques corresponded most closely with the < 1,000 Da molecular weight fraction defined as "truly soluble COD". Centrifugation of wastewater samples amended with mercuric chloride (HgCl2) at 10 mg/L overestimated the soluble COD concentration. Our results confirm that coagulation using either ZnSO4 or LaCI3 is appropriate for the rapid determination of soluble COD fraction in wastewater matrices.     

第20届国际特种加工会议综述

对第20届国际特种加工会议发表的论文进行了全面综述,介绍了近年来国际特种加工领域的最新研究进展,主要内容包括电火花加工、电化学加工、增材制造、激光加工、电子束加工以及等离子及复合加工工艺的代表性研究成果.     

脉冲电磁场对骨质疏松的生物效应

电磁场作为非创伤性疗法在骨病治疗中已得到广泛的关注,故清华大学深圳研究生院以近10年的工作为基础,从细胞水平、动物模型和临床研究3个方面总结了脉冲电磁场应用于防治骨质疏松研究所取得的成果。研究发现,电磁场能够促进DNA的合成和影响成骨细胞的增殖和分化,且其效果存在一定的窗口效应;骨质疏松动物模型研究显示,脉冲电磁场能够改善去势诱导骨质疏松模型骨密度;初步临床实验证实了细胞研究和动物模型研究的作用效果,并且能够有效改善骨质疏松病人的疼痛和改善骨密度水平。因此认为脉冲电磁场将在骨质疏松的防治中发挥重要作用。     

脉冲电磁场预防骨质疏松模型的实验研究

为检验脉冲电磁场对去卵巢大鼠骨质疏松模型的预防效果,用30只质量180-220 g 3月龄雌性未孕SD大鼠去势建立骨质疏松模型,并随机分成正常对照组(SHAM)、去势对照组(OVX)、脉冲电磁场(PEMFs)组,每组10只,其中SHAM组作假手术,不切除卵巢,其余2组做双侧卵巢切除术;PEMFs组选用15 Hz脉冲电磁场,2 h/d,1次/d;SHAM组和OVX组不予任何处理,分别作为阳、阴性对照组,并用双能X射线骨密度仪检测腰椎和股骨骨密度。实验结果表明,脉冲电磁场照射后,校正骨密度低于正常对照组;与OVX组相比,脉冲电磁场照射后去势大鼠椎骨校正骨密度(16周时,P<0.001和24周时P<0.01)和股骨校正骨密度(16周时P<0.001和24周时P<0.01)提高,脉冲电磁场能改善去势大鼠骨质疏松具有预防作用,对脉冲电磁场应用于人体骨质疏松相关疾病的防治具有现实意义。     

Field performance assessment of onsite individual wastewater treatment systems.

On-site individual wastewater treatment systems can provide a financially attractive alternative to a sewer connection in locations far from the existing sewer network. These systems are, however, relatively new, and therefore, shortcomings in the design or operation problems still occur frequently. A previously performed survey revealed that most system owners neither carry out routine operation and maintenance tasks nor have a maintenance agreement with the manufacturer. This suggests that in reality, systems are often improperly managed and do not provide the level of treatment necessary to adequately protect surface and ground waters. To substantiate this statement, the field performance of 23 currently installed individual wastewater treatment systems in Belgium has been assessed.The results of this study confirm that many installed individual systems do not perform well: 52% of them do not meet all the legal effluent standards (BOD, COD, SS). Activated sludge systems prove to be less efficient than biofilm-based systems and extensive systems perform better than compact systems. Maintenance problems and to a lesser extent improperly designed systems are indeed the main cause of unsatisfactory results through, e.g., wash out.