Insights into stem cell therapy for diabetic retinopathy: a bibliometric and visual analysis

Stem cells have been confirmed to be involved in the occurrence and development of diabetic retinopathy;however,the underlying mechanisms remain unclear.In this study,we used Citespace software to visually analyze 552 articles exploring the stem cell-based treatment of diabetic retinopathy over the past 20 years,which were included in the Web of Science Core Collection.We found the following:(1)a co-citation analysis of the references cited by all 552 articles indicated 15 clusters.In cluster#0,representing the stem cell field,some highly cited landmark studies emerged between 2009–2013.For example,endothelial progenitor cells and diabetic retinopathy gradually received the full attention of scholars,in terms of their relationship and therapeutic prospects.Some researchers also verified the potential of adipose-derived stem cells to differentiate into stable retinal perivascular cells,using a variety of animal models of retinal vascular disease.All of these achievements provided references for the subsequent stem cell research.(2)An analysis of popular keywords among the 552 articles revealed that,during the past 20 years,a relative increase in basic research articles examining stem cells and endothelial progenitor cells for the treatment of diabetic retinopathy was observed.The contents of these articles primarily involved the expression of vascular endothelial growth factor,vascular regeneration,oxidative stress,and inflammatory response.(3)A burst analysis of keywords used in the 552 articles indicated that genetic and cytological research regarding the promotion of angiogenesis was an issue of concern from 2001 to 2012,including several studies addressing the expression of various growth factor genes;from 2014 to 2020,mouse models of diabetic retinopathy were recognized as mature animal models,and the most recent research has focused on macular degeneration,macular edema,neurodegeneration,and inflammatory changes in diabetic animal models.(4)Globally,the current authoritative studies have focused on basic research towards the stem cell treatment of diabetic retinopathy.Existing clinical studies are of low quality and have insufficient evidence levels,and their findings have not yet been widely accepted in clinical practice.Major challenges during stem cell transplantation remain,including stem cell heterogeneity,cell delivery,and the effective homing of stem cells to damaged tissue.However,clinical trials examining potential stem cell-based treatments of diabetic retinopathy,including the use of pluripotent stem cells,retinal pigment epithelial cells,bone marrow mesenchymal stem cells,and endothelial progenitor cells,are currently ongoing,and high-quality clinical evidence is likely to appear in the future,to promote clinical transformation.

The Non-inclusion Diagnosability of Hypercubes Under the PMC Model

Diagnosability of a multiprocessor system is an important measure of the reliability of interconnection networks.System-level diagnosis is a primary strategy to identify the faulty processors in a multiprocessor system.Based on a sound assumption proposed by Zhu et al.recently,we proposed a new diagnosability named non-inclusion diagnosability and showed that the non-inclusion diagnosability tN(Q_(n))of the hypercube under the PMC model is 2n-2.That is,assume that if two vertex sets Fi and F2 are both consistent with a syndrome and F_(1)C F_(2),then F2 is not the faulty set which we are looking for;the faulty set F is 1-step diagnosable if|F|≤2n-2 in Qn under the PMC model.

Wideband switchable dual-functional terahertz polarization converter based on vanadium dioxide-assisted metasurface

The terahertz technology has attracted considerable attention because of its potential applications in various fields.However,the research of functional devices,including polarization converters,remains a major demand for practical applications.In this work,a reflective dual-functional terahertz metadevice is presented,which combines two different polarization conversions through using a switchable metasurface.Different functions can be achieved because of the insulator-to-metal transition of vanadium dioxide(VO_(2)).At room temperature,the metadevice can be regarded as a linear-to-linear polarization convertor containing a gold circular split-ring resonator(CSRR),first polyimide(PI)spacer,continuous VO_(2) film,second PI spacer,and gold substrate.The converter possesses a polarization conversion ratio higher than 0.9 and a bandwidth ratio of 81%in a range from 0.912 THz to 2.146 THz.When the temperature is above the insulator-to-metal transition temperature(approximately 68℃)and VO_(2) becomes a metal,the metasurface transforms into a wideband linear-to-circular polarization converter composed of the gold CSRR,first PI layer,and continuous VO_(2) film.The ellipticity is close to-1,while the axis ratio is lower than 3 dB in a range of 1.07 THz-1.67 THz.The metadevice also achieves a large angle tolerance and large manufacturing tolerance.