Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes

Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs.The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)steps.First,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual microneedle.Then,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate.Subsequently,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures.Depending on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the substrate.With these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si wafer.Insertion tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain.To demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding processes.The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on.

PotholeEye^(+): Deep-Learning Based Pavement Distress Detection System toward Smart Maintenance

We propose a mobile system,called PotholeEye+,for automatically monitoring the surface of a roadway and detecting the pavement distress in real-time through analysis of a video.PotholeEye+pre-processes the images,extracts features,and classifies the distress into a variety of types,while the road manager is driving.Every day for a year,we have tested PotholeEye+on real highway involving real settings,a camera,a mini computer,a GPS receiver,and so on.Consequently,PotholeEye+detected the pavement distress with accuracy of 92%,precision of 87%and recall 74%averagely during driving at an average speed of 110 km/h on a real highway.

Manipulating Nanowires in Interconnecting Layer for Efficient Tandem Organic Photovoltaics

Owing to the function of manipulating light absorption distribution,tandem organic solar cells containing multiple sub-cells exhibit high power conversion efficiencies.However,there is a substantial challenge in precisely controlling the inter-subcells carrier migration which determines the balance of charge transport across the entire device.The conductivity of"nanowires"-like conducting channel in interconnecting layer between sub-cells should be improved which calls for fine engineering on the morphology of polyelectrolyte in interconnecting layer.Here,we develop a simple method to effectively manipulating the domains of conductive components in commercially available polyelectrolyte PEDOT:PSs.The use of poor solvent could effectively modify the configuration of polystyrene sulfonic acid and thus the space for conductive components.Based on our strategy,the insulated shells wrapping conductive domains are thinned and the efficiencies of tandem organic solar cells are improved.We believe our method might provide guidance for the manufacture of tandem organic solar cells.

Safety of acupotomy in a real-world setting:A prospective pilot and feasibility study

Objective:Acupotomy is a modern acupuncture method that includes modern surgical methods.Since acupotomy is relatively more invasive than filiform acupuncture treatment,it is important to establish the safety profile of this practice.To justify further large-scale prospective observational studies,this preliminary study was performed to assess the feasibility of the approach and investigate the safety profile and factors potentially associated with adverse events(AEs).Methods:This was a prospective pilot study that assessed the feasibility of a large-scale forthcoming safety study on acupotomy treatment in a real-world setting.The feasibility(call response rate,dropout rate,response rate for each variable and recruitment per month)and safety profile(incidence,type,severity and causality of AEs,and factors potentially associated with AEs)were measured.Results:A total of 28 participants joined the study from January to May 2018.A follow-up assessment was achieved in 258(1185 treatment points)out of 261 sessions(1214 treatment points).The response rate via telephone on the day after treatment was 87.3%.There were 8 systemic AEs in all the sessions(8/258;3.11%)and 27 local AEs on the total points treated(27/1185;2.28%).Severe AEs did not occur.Total AE and local AE occurrence were associated with blade width and the number of needle stimulations per treatment point.Conclusion:The findings suggest that it could be feasible to analyze the safety of acupotomy in a realworld setting.Moreover,the primary data on some relevant AEs could be determined.We are planning large-scale prospective studies based on these findings.Trial registration:Clinical Research Information Service(CRIS)KCT0002849(https://cris.nih.go.kr/cris/search/detailSearch.do/11487).