Improvement of Thermal Stability and Tribological Performance of Diamond-Like Carbon Composite Thin Films

Diamond-like carbon (DLC) is a metastable amorphous film that exhibits unique properties. However, many limitations exist regarding the use of DLC, for example, its tribological characteristics at high temperature, as well as its limited thermal stability. In this study, silicon/oxygen and silicon/nitrogen co-incorporated diamond-like carbon (Si-O-DLC and Si-N-DLC) films are studied, taking into account the thermal stability and tribological performance of these films compared with pure DLC. All the films were prepared on Si wafers, WC-Co materials, and aluminum foils using a plasma-based ion implantation (PBII) technique using acetylene (C2H2), tetramethylsilane (TMS, Si(CH3)4), oxygen (O2) and nitrogen (N2) as plasma sources. The structure of the films was characterized using Raman spectroscopy. The thermal stability of the films was measured using thermogravimetric and differential thermal analysis (TG-DTA). The friction coefficient of the films was assessed using ball-on-disk friction testing. The results indicate that Si-N-DLC films present better thermal stability due to the presence of Si-O networks in the films. The Si-N-DLC (23 at.%Si, 8 at.%N) film was affected using thermal annealing in an air atmosphere with increasing temperature until 500°C. The film can also resist thermal shock by cycling 10 times between the various temperatures and air atmosphere until 500°C. Further, Si-O-DLC and Si-N-DLC films exhibit excellent tribological performance, especially the Si-N-DLC (23 at.%Si, 8 at.%N) film, which exhibits excellent tribological performance at 500°C in an air atmosphere. It is concluded that Si-O-DLC and Si-N-DLC films improve upon the thermal stability and tribological performance of DLC.

Renewable biosynthesis of isoprene from wastewater through a synthetic biology approach:the role of individual organic compounds

The biosynthesis of isoprene offers a more sustainable alternative to fossil fuel-based approaches,yet its success has been largely limited to pure organic compounds and the cost remains a challenge.This study proposes a waste-to-wealth strategy for isoprene biosynthesis utilizing genetically engineered E.coli bacteria to convert organic waste from real food wastewater.The impact of organic compounds present in wastewater on E.coli growth and isoprene production was systematically investigated.The results demonstrated that with filtration pretreatment of wastewater,isoprene yield,and production achieved 115 mg/g COD and 7.1 mg/(L·h),respectively.Moreover,even without pretreatment,isoprene yield only decreased by~24%,indicating promising scalability.Glucose,maltose,glycerol,and lactate are effective substrates for isoprene biosynthesis,whereas starch,protein,and acetate do not support E.coli growth.The optimum C/N ratio for isoprene production was found to be 8:1.Furthermore,augmenting essential nutrients in wastewater elevated the isoprene yield increased to 159 mg/g COD.The wastewater biosynthesis significantly reduced the cost(44%–53%decrease,p-value<0.01)and CO_(2)emission(46%–55%decrease,p-value<0.01)compared with both sugar fermentation and fossil fuel–based refining.This study introduced a more sustainable and economically viable approach to isoprene synthesis,offering an avenue for resource recovery from wastewater.

Photosynthetic microorganisms coupled photodynamic therapy for enhanced antitumor immune effect

The ideal photodynamic therapy(PDT)should effectively remove the primary tumor,and produce a stronger immune memory effect to inhibit the tumor recurrence and tumor metastasis.However,limited by the hypoxic and immunosuppressive microenvironment,the PDT efficiency is apparently low.Here,Chlorella(Chl.)is exploited to enhance local effect by producing oxygen to reverse hypoxia,and release adjuvants to reverse immunosuppressive microenvironment to enhance abscopal effect afterwards.Results from different animal models indicated that Chl.could enhance local effect and PDT related immune response.Ultimately,Chl.coupled PDT elicited anti-tumor effects toward established primary tumors(inhibition rate:90%)and abscopal tumors(75%),controlled the challenged tumors(100%)and alleviated metastatic tumors(90%).This Chl.coupled PDT strategy can also produce a stronger anti-tumor immune memory effect.Overall,this Chl.coupled PDT strategy generates enhanced local tumor killing,boosts PDT-induced immune responses and promotes anti-tumor immune memory effect,which may be a great progress for realizing systemic effect of PDT.

脓毒症与铁代谢的研究进展

脓毒症是一种由感染引起的常见的全身炎症反应综合征,具有高发病率和高病死率的特征,已成为重要的公共健康问题之一。脓毒症及其发病机制和治疗也一直是研究重点。2016年,脓毒症被重新定义为由宿主对感染的反应失调引起的危及生命的器官功能障碍模式。近年来,针对脓毒症患者的免疫反应及代谢变化开展了大量临床及实验研究,其中铁代谢与脓毒症的关系也是研究重点之一。铁在调节免疫功能和微生物生长方面有着关键作用,已有研究证明铁代谢的变化会影响感染的风险。本文旨在对铁代谢与脓毒症及脓毒症诱导的多器官功能障碍的关系等作简要概述,以期对脓毒症的预后预测及治疗提供新的方向。