数控滚齿机参数化自动编程系统开发

为了提高齿轮加工效率,提出了一种基于滚齿加工的自动编程系统。在分析齿轮滚削加工工艺的基础上,建立了齿轮加工的数学模型,进而得到数控滚齿加工的NC程序。该方法仅需通过人机界面输入工件、刀具和工艺等参数,在工艺数据库和运算库的支撑下,即可自动生成NC程序。针对广州数控218MC数控系统,通过用户宏程序进行了自动编程系统的开发,实现了人机界面设计、滚齿算法设计和功能模块设计。最后,通过在工厂多台五轴滚齿机上的应用表明该系统编程效率高、加工零件精度高、算法可靠性强的特点,同时降低了机床操作人员的职业技术门槛,提升了国产齿轮数控系统的市场竞争力。

Human iPSCs derived astrocytes rescue rotenone-induced mitochondrial dysfunction and dopaminergic neurodegeneration in vitro by donating functional mitochondria

Background Parkinson’s disease(PD)is one of the neurodegeneration diseases characterized by the gradual loss of dopaminergic(DA)neurons in the substantia nigra region of the brain.Substantial evidence indicates that at the cellular level mitochondrial dysfunction is a key factor leading to pathological features such as neuronal death and accumulation of misfoldedα-synuclein aggregations.Autologous transplantation of healthy purified mitochondria has shown to attenuate phenotypes in vitro and in vivo models of PD.However,there are significant technical difficulties in obtaining large amounts of purified mitochondria with normal function.In addition,the half-life of mitochondria varies between days to a few weeks.Thus,identifying a continuous source of healthy mitochondria via intercellular mitochondrial transfer is an attractive option for therapeutic purposes.In this study,we asked whether iPSCs derived astrocytes can serve as a donor to provide functional mitochondria and rescue injured DA neurons after rotenone exposure in an in vitro model of PD.Methods We generated DA neurons and astrocytes from human iPSCs and hESCs.We established an astroglial-neuronal co-culture system to investigate the intercellular mitochondrial transfer,as well as the neuroprotective effect of mitochondrial transfer.We employed immunocytochemistry and FACS analysis to track mitochondria.Results We showed evidence that iPSCs-derived astrocytes or astrocytic conditioned media(ACM)can rescue DA neurons degeneration via intercellular mitochondrial transfer in a rotenone induced in vitro PD model.Specifically,we showed that iPSCs-derived astrocytes from health spontaneously release functional mitochondria into the media.Mito-Tracker Green tagged astrocytic mitochondria were detected in the ACM and were shown to be internalized by the injured neurons via a phospho-p38 depended pathway.Transferred mitochondria were able to significantly reverse DA neurodegeneration and axonal pruning following exposure to rotenone.When rotenone injured neurons were cultured in presence of ACM depleted of mitochondria(by ultrafiltration),the neuroprotective effects were abolished.Conclusions Our studies provide the proof of principle that iPSCs-derived astrocytes can act as mitochondria donor to the injured DA neurons and attenuate pathology.Using iPSCs derived astrocytes as a donor can provide a novel strategy that can be further developed for cellular therapy for PD.

Optimization of cerebral organoids:a more qualified model for Alzheimer’s disease research

Alzheimer’s disease(AD)is a neurodegenerative disease that currently cannot be cured by any drug or intervention,due to its complicated pathogenesis.Current animal and cellular models of AD are unable to meet research needs for AD.However,recent three-dimensional(3D)cerebral organoid models derived from human stem cells have provided a new tool to study molecular mechanisms and pharmaceutical developments of AD.In this review,we discuss the advantages and key limitations of the AD cerebral organoid system in comparison to the commonly used AD models,and propose possible solutions,in order to improve their application in AD research.Ethical concerns associated with human cerebral organoids are also discussed.We also summarize future directions of studies that will improve the cerebral organoid system to better model the pathological events observed in AD brains.