Advances in microfluidic-based DNA methylation analysis

DNA methylation has been extensively investigated in recent years,not least because of its known relationship with various diseases.Progress in analytical methods can greatly increase the relevance of DNA methylation studies to both clinical medicine and scientific research.Microflu-idic chips are excellent carriers for molecular analysis,and their use can provide improvements from multiple aspects.On-chip molecular analysis has received extensive attention owing to its advantages of portability,high throughput,low cost,and high efficiency.In recent years,the use of novel microfluidic chips for DNA methylation analysis has been widely reported and has shown obvious superiority to conventional methods.In this review,wefirst focus on DNA methylation and its applications.Then,we discuss advanced microfluidic-based methods for DNA methylation analysis and describe the great progress that has been made in recent years.Finally,we summarize the advantages that microfluidic technology brings to DNA methylation analysis and describe several challenges and perspectives for on-chip DNA methylation analysis.This review should help researchers improve their understanding and make progress in developing microfluidic-based methods for DNA methylation analysis.

An electrochemiluminescent magneto-immunosensor for ultrasensitive detection of hs-cTnI on a microfluidic chip

Sensitive detection and precise quantitation of trace-level crucial biomarkers in a complex sample matrix has become an important area of research.For example,the detection of high-sensitivity cardiac troponin I (hs-cTnI) is strongly recommended in clinical guidelines for early diagnosis of acute myocardial infarction.Based on the use of an electrode modified by single-walled carbon nanotubes (SWCNTs) and a Ru(bpy)32+-doped silica nanoparticle (Ru@SiO2)/tripropylamine (TPA) system,a novel type of electrochemiluminescent (ECL) magnetoimmunosensor is developed for ultrasensitive detection of hs-cTnI.In this approach,a large amount of[Ru(bpy)3]2+is loaded in SiO2(silica nanoparticles) as luminophores with high luminescent efficiency and SWCNTs as electrode surface modification material with excellent electrooxidation ability for TPA.Subsequently,a hierarchical micropillar array of microstructures is fabricated with a magnet placed at each end to efficiently confine a single layer of immunomagnetic microbeads on the surface of the electrode and enable 7.5-fold signal enhancement In particular,the use of transparent SWCNTs to modify a transparent ITO electrode provides a two-order-of-magnitude ECL signal amplification.A good linear calibration curve is developed for hs-cTnI concentrations over a wide range from 10 fg/ml to 10 ng/ml,with the limit of detection calculated as 8.720 fg/ml (S/N=3).This ultrasensitive immunosensor exhibits superior detection performance with remarkable stability,reproducibility,and selectivity.Satisfactory recoveries are obtained in the detection of hs-cTnI in human serum,providing a potentia analysis protocol for clinical applications.

不同方法对根管内氢氧化钙去除效果的micro-CT评价

目的:应用显微CT(micro-computed tomography,micro-CT)建立磨牙根管模型,评价不同方法对氢氧化钙的清除效率。方法:收集2023年10月—2024年2月口腔综合科门诊拔除的11颗磨牙(24个根管),按照标准根管治疗流程,镍钛器械预备完成后,在根管内置入氢氧化钙,1周后,根据不同冲洗方法将样本随机分为侧方开口注射器组、超声荡洗组(EMS组)和声波震荡组(EDDY组)等3组(n=8)。冲洗前后使用micro-CT重建根管系统并使用不同颜色标记独立根管,计算各个根管氢氧化钙体积,比较各组氢氧化钙清除率。采用SPSS 19.0软件包对数据进行统计学分析。结果:3种方法均无法完全去净根管内氢氧化钙。使用次氯酸钠作为冲洗液时,超声荡洗和声波震荡清除效果优于侧方开口冲洗器(P<0.05);超声荡洗和声波震荡去除氢氧化钙效率相当,差异无统计学意义(P>0.05);氢氧化钙残留部位集中于根尖区。结论:Micro-CT能较为高效地重建磨牙根管模型,可用于评价氢氧化钙去除效果。超声荡洗组和声波震荡组清除氢氧化钙效率相当,优于侧方开口注射器组。

Micro LED车灯投影光学系统设计与优化

本文提出了一种基于Micro LED阵列的车灯投影方案,设计了以像素尺寸为80μm×80μm的200×150白光Micro LED阵列作为显示光源,视场角为16°×34°的车灯投影光学系统,并对物面倾斜角度和光学系统结构进行了优化。此外,分别采用反向畸变处理方法和像素灰度调制方法用以解决车灯投影图像的梯形畸变和照度均匀性问题,并搭建了投影实验平台,对图像校正方法进行了验证。实验结果表明:校正后图像梯形畸变系数p1,p2分别从0.0932和0.3680下降至0.0835和0.0373,像面照度均匀性从83.2%提高到93.2%。本文通过对基于Micro LED的倾斜投影车灯光学系统进行优化设计及采用图像校正方法,实现了高光效、低畸变的车灯投影。

光子晶体Micro LED微显示阵列加工及光学特性分析

Micro LED器件具有高亮度、低功耗和高可靠性等优点,但Micro LED显示像素巨量转移和光提取效率低的问题为其应用带来挑战。开发了具有高转移效率和出光效率的单片64×64 Micro LED微显示阵列,提出了倒装型GaN基单片Micro LED微显示阵列芯片和Si基驱动电路的设计方法及集成工艺。通过时域有限差分(FDTD)方法对Micro LED微显示阵列光学特性进行了建模分析,设计了一种提高Micro LED微显示阵列出光效率的光提取结构。结合仿真结果,开发了一种在Micro LED蓝宝石衬底表面制备光子晶体结构的聚焦离子束(FIB)微纳加工工艺,并进行了器件加工。测试结果表明,蓝宝石衬底上加工的光子晶体结构可以提高Micro LED器件的表面出光效率,光功率平均值提升了16.36%,对Micro LED微显示阵列加工及微显示像素光提取问题具有借鉴意义。

基于Micro CT的铜导线短路熔痕孔洞特征分析

导线短路是造成电气火灾的重要原因之一。现行国家标准中将导线短路熔痕分为起火前发生的一次短路熔痕和起火后造成的二次短路熔痕,然而现行国家标准中的鉴定仅停留在定性判断的阶段。火灾现场铜导线短路熔痕特征的量化分析研究是国内外研究人员主要关注的重点。本文应用Micro CT技术对铜导线短路熔痕进行断层扫描检测并重构铜导线短路熔痕的3D图像数据,在此基础上统计、归纳、总结铜导线短路熔痕内部孔洞形态及分布等孔洞特征。研究表明,Micro CT能够全面采集铜导线短路熔痕的整体形态和内部孔洞特征,一次短路熔痕与二次短路熔痕内部孔洞半径、表面积、紧密度的特征数据存在差别,可为短路熔痕定性和定量分析判据研究提供新的理论依据。

Micro-CT分析跟骨内骨小梁分布及结构特征

背景:跟骨位于足的后下部,受力较大。跟骨外形复杂且不规则,外周有较薄的皮质骨包绕,内部充满大量的骨小梁,探讨骨小梁的微观结构、走行及分布特征有助于提高对跟骨骨折的认识。目的:采用微计算机断层扫描仪(Micro-CT)扫描跟骨标本获得其影像资料,对其内部骨小梁结构进行分析,探讨跟骨内骨小梁的形态、分布及结构特征。方法:采用Micro-CT连续扫描干燥成人跟骨标本,扫描后获得影像图像,将其以DICOM格式存储。导入影像资料到Hiscan Analyzer软件,显示清晰完整的成人跟骨矢状面、冠状面、水平面的图像,逐层观察骨小梁的走行,依据骨小梁走行特点将跟骨矢状面分为6个部分,在以7 mm为标准的相同厚度下,每个部分选择1个49 mm2等面积的兴趣区,三维重建后获得跟骨及骨小梁的立体微观结构,二值化后运用软件计算感兴趣区域内骨小梁的体积分数、表面密度、骨小梁厚度、骨小梁间隙和骨小梁数量参数。结果与结论:①跟骨表面皮质层很薄,内部充满大量骨松质,在Gissane角的骨皮质明显增厚;②跟骨上部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨结节部、跟骨底部,跟骨结节部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨底部;跟骨结节部的骨小梁表面密度大于跟骨下部前端、中和三角区、跟骨底部,跟骨上部、跟骨下后部的骨小梁表面密度大于中和三角区;跟骨上部的骨小梁厚度大于跟骨结节部;中和三角区的骨小梁间隙大于跟骨上部、跟骨结节部;跟骨结节部的骨小梁数量大于中和三角区;③中和三角区主要分布杆状骨小梁,骨小梁表面密度最小、体积分数较小、骨小梁间隙最大;该部位骨质较疏松,受到高冲击力时抗压缩能力差,骨小梁最先发生断裂,是易发生骨折的部位。

Micro segment analysis of supercritical methane thermal-hydraulic performance and pseudo-boiling in a PCHE straight channel

The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So heat transfer deterioration should be taken seriously in the design and safe operation of vaporizer PCHE. The study of this work clarified the local heat transfer and flow feature of supercritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.

高亮绿光氮化镓基Micro-LED微型显示器制备

Micro-LED作为一种新型的显示技术,具有对比度高、响应快及寿命长等优点,已成为当前研究的热点。然而,尽管潜力巨大,Micro-LED技术的商业化之路仍面临诸多技术上的挑战与瓶颈。本文旨在探讨高亮绿光氮化镓基Micro-LED微型显示器的制备过程及其相关技术。基于WVGA041全数字信号电路CMOS硅基驱动电路,制作了0.41 inch、分辨率为800×480的主动式单色绿光Micro-LED微型显示器。利用高精度倒装焊接技术实现了CMOS驱动电路与LED发光芯片的电气连接。结果表明,制备出LED显示芯片正常启亮电压为2.8V,EL光谱峰值波长524nm;在硅基CMOS电路驱动范围内,Micro-LED微型显示器在5V电压下,器件亮度为108000cd/m^(2)(最大亮度可达250000 cd/m^(2)),电流密度达到0.61A/cm^(2)时色坐标为(0.175,0.756)。当电流密度从0.3A/cm^(2)增加到1.3A/cm^(2)时,色坐标从(0.178,0.757)变化到(0.175,0.746),器件的色稳定性能够满足实际应用要求。

Micro RNAs与急性心肌梗死关系的研究进展

急性心肌梗死(acute myocardial infarction,AMI)是冠状动脉疾病最严重的表现,其引起的心肌组织损伤可促进心力衰竭的发展。尽管近些年由于生活方式的改变、治疗方式(如经皮冠状动脉介入治疗)的发展使AMI的预后得到了改善,但是AMI依旧每年危害着全球700多万人的身心健康,AMI仍然是世界范围内高发病率和高死亡率的主要疾病之一[1]。微小RNA(micro RNAs,miRNAs)是在20世纪90年代被发现的,mi RNAs的研究已经迅速发展成为一个成熟而广阔的领域。mi RNAs存在于几乎所有类型的细胞和细胞的病理生理活动中,包括与心血管系统相关的细胞。本文将mi RNAs对AMI病理生理进程的影响进行综述,希望为临床治疗提供新思路。

基于量子点@有序介孔复合材料的Micro⁃LED色转换特性

量子点(Quantum dots)由于具有优异的光电特性,广泛应用于发光与显示、太阳能电池、光催化等领域,它的发现和合成获得了2023年诺贝尔化学奖。采用量子点色转换的Micro-LED全彩化显示技术无需巨量转移,有望实现大规模量产,然而,量子点在高强度Micro-LED出光激发下的性能和寿命仍存在局限。基于此,本文研究了基于量子点@有序介孔(QDs@SBA-15)复合材料的Micro-LED色转换技术及其特性,有序介孔分子筛载体独特的孔道结构不仅能够有效提升Micro-LED色转换和光提取效率,且致密的有序介孔材料也一定程度上保障了量子点的稳定性。首先,通过时域有限差分方法(FDTD)建立了Micro-LED仿真模型,探究量子点粒径和有序介孔材料的孔径对光提取效率的影响;基于仿真结果指导,进一步采用物理共混法制备了QDs@SBA-15复合材料,通过透射光谱、荧光激发光谱、紫外-可见光吸收谱等手段对其进行表征并确定浓度配比;最后,将该复合材料与聚二甲基硅氧烷(PDMS)混合固化成膜,并研究了其光致发光性能。实验结果发现,量子点粒径和介孔材料孔径的匹配度以及量子点和有序介孔材料的比例浓度是影响QDs@SBA-15复合材料发光效率及Micro-LED色转换性能的关键因素;通过优化,所得复合材料可获得优异的发光性能以及良好的环境稳定性,相比于纯量子点色转换层,复合材料的光提取效率提升了81.73%,复合材料的环境稳定性提升了14.33%,以Micro-LED作为蓝光光源组成的三基色发光器件工作色域达到了104.52%NTSC。本研究为量子点色转换Micro-LED显示技术提供了理论指导,为实现Micro-LED全彩化开辟了新路径。

Lugol's iodine增强Micro-CT成像评估口腔鳞状细胞癌切缘状态的研究

目的:本研究拟使用Lugol's iodine增强Micro-CT成像三维评估口腔鳞状细胞癌(oral squamous cell carcinoma,OSCC)切缘状态。方法:本研究共收集68例人OSCC组织样本,所有样本经3%Lugol's iodine染色12 h后行Micro-CT扫描(层厚为50μm)。随后将经Lugol's iodine染色后的样品行常规苏木精-伊红(hematoxylin-eosin,HE)染色切片(厚度为4μm),制作数字化病理切片。分别测量影像图像和病理图像的黏膜切缘(mucosal margin,MM)和深部切缘(deep margin,DM)。结果:Lugol's iodine增强Micro-CT成像可以在三维空间中清晰区分肿瘤边界,且Micro-CT成像相较于二维病理切片,可以更准确地测量MM和DM,发现阳性切缘及临界切缘。结论:Lugol's iodine增强Micro-CT成像可以全面评估OSCC切缘,提供更全面、更清晰的肿瘤边缘信息,指导临床治疗方案选择和预后评估。

Flexible planar micro supercapacitor diode

Supercapacitor diode is a novel ion device that performs both supercapacitor energy storage and ion diode rectification functions.However,previously reported devices are limited by their large size and complex processes.In this work,we demonstrate a screen-printed micro supercapacitor diode(MCAPode)that based on the insertion of a finger mode with spinel ZnCo_(2)O_(4) as cathode and activated carbon as anode for the first time,and featuring an excellent area specific capacitance(1.21 mF cm^(-2)at 10 mV s^(-1))and high rectification characteristics(rectification ratioⅠof 11.99 at 40 mV s^(-1)).Taking advantage of the ionic gel electrolyte,which provides excellent stability during repeated flexing and at high temperatures.In addition,MCAPode exhibits excellent electrochemical performance and rectification capability in"AND"and"OR"logic gates.These findings provide practical solutions for future expansion of micro supercapacitor diode applications.

Engineering the spectra of photon triplets generated from micro/nanofiber

Quantum light sources are the core resources for photonics-based quantum information processing.We investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversion in micro/nanofiber.The phase mismatching at one-third pump frequency gives rise to non-degenerate photon triplets,the joint spectral intensity of which has an elliptical locus with a fixed eccentricity of√6/3.Therefore,we propose a frequency-division scheme to separate non-degenerate photon triplets into three channels with high heralding efficiency for the first time.Choosing an appropriate pump wavelength can compensate for the fabrication errors of micro/nanofiber and also generate narrowband,non-degenerate photon triplet sources with a high signal-to-noise ratio.Furthermore,the long-period micro/nanofiber grating introduces a new controllable degree of freedom to tailor phase matching,resulting from the periodic oscillation of dispersion.In this scheme,the wavelength of photon triplets can be flexibly tuned using quasi-phase matching.We study the generation of photon triplets from this novel perspective of spectrum engineering,and we believe that this work will accelerate the practical implementation of photon triplets in quantum information processing.

Macroscopic and microscopic mechanical behavior and seepage characteristics of coal under hydro-mechanical coupling

Understanding the physical,mechanical behavior,and seepage characteristics of coal under hydro-mechanical coupling holds significant importance for ensuring the stability of surrounding rock formations and preventing gas outbursts.Scanning electron microscopy,uniaxial tests,and triaxial tests were conducted to comprehensively analyze the macroscopic and microscopic physical and mechanical characteristics of coal under different soaking times.Moreover,by restoring the stress path and water injection conditions of the protective layer indoors,we explored the coal mining dynamic behavior and the evolution of permeability.The results show that water causes the micro-surface of coal to peel off and cracks to expand and develop.With the increase of soaking time,the uniaxial and triaxial strengths were gradually decreased with nonlinear trend,and decreased by 63.31%and 30.95%after soaking for 240 h,respectively.Under different water injection pressure conditions,coal permeability undergoes three stages during the mining loading process and ultimately increases to higher values.The peak stress of coal,the deviatoric stress and strain at the permeability surge point all decrease with increasing water injection pressure.The results of this research can help improve the understanding of the coal mechanical properties and seepage evolution law under hydro-mechanical coupling.

Effect of wire diameter compression ratio on drawing deformation of micro copper wire

A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity theory.The impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was investigated.Results indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip zones.Additionally,horizontal strain concentration bands develop within the drawn wire.As the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also increase.However,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process.

Efficacy and Safety of Micropulse Trans-Scleral Cyclophotocoagulation in Cambodian Patients with Glaucoma

Objective: To evaluate the treatment outcomes of micropulse cyclophotocoagulation in Cambodian glaucoma patients. Materials and Methods: 14 patients were enrolled in this retrospective study that was conducted with the consent over a 14-month period. The medical records were analyzed for variables such as intra-ocular pressure, the number of anti-glaucoma drugs used, visual acuity, pain level, and complications during and after treatment. The main outcome was whether or not there was success or failure, with success being defined as a pressure level between 6 and 21 mmHg and a 30% decrease in IOP by week 24 (with/without drugs). Results: In our study, the mean age of patients was 52.36 ± 9.98 years old (42 to 75 years old). The mean intra-ocular pressure before treatment was 41.00 ± 12.26 mmHg, which decreased to 21.60 ± 8.11 mmHg (41.56% reduction) and 16.94 ± 5.46 mmHg (56.04% reduction) in the 12th and 24th weeks (p p Conclusion: Micro-pulse trans-scleral cyclophotocoagulation is a safe and effective method for lowering pressure in any stage of disease without the use of invasive surgeries.

Clinical experience sharing on gastric microneuroendocrine tumors: A case report

BACKGROUND The majority of gastric neuroendocrine tumors(G-NENs)are present in various lesions under endoscopy,and they can be polypoid uplifts,submucosal tumors or papules,erosions,and ulcers.The lesions are mostly confined to the mucosal or submucosal layer,usually less than 2 cm,and exclusively localized to the gastric body or fundus.In type 1 G-NENs,about 22%of cases have no visible lesions under an endoscope,and such lesions can only be detected via biopsies(microcar-cinoids).CONCLUSION In the case under study,the patient did not have any visible raised lesions under a gastroscope,and the lesions were found only after a random biopsy.This article combines the endoscopic manifestations and clinical features of the lesions in this case to improve the diagnosis of G-NENs.

Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive loads.In this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were revealed.After the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro defects.In addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the plate.The stress parameters of the observation points were obtained through an effective numerical model.The mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro defects.The result shows that the generation and expansion of micro defects are related to the stress area(i.e.the upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile stress.Besides,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(i.e.the horizontal direction) were also studied.It was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decreased with the increase of the distance from the explosion center.

Dynamic Resistance and Energy Absorption of Sandwich Beam via a Micro-Topology Optimization

The current research of sandwich structures under dynamic loading mainly focus on the response characteristic of structure.The micro-topology of core layers would sufficiently influence the property of sandwich structure.However,the micro deformation and topology mechanism of structural deformation and energy absorption are unclear.In this paper,based on the bi-directional evolutionary structural optimization method and periodic base cell(PBC)technology,a topology optimization frame work is proposed to optimize the core layer of sandwich beams.The objective of the present optimization problem is to maximize shear stiffness of PBC with a volume constraint.The effects of the volume fraction,filter radius,and initial PBC aspect ratio on the micro-topology of the core were discussed.The dynamic response process,core compression,and energy absorption capacity of the sandwich beams under blast impact loading were analyzed by the finite element method.The results demonstrated that the overpressure action stage was coupled with the core compression stage.Under the same loading and mass per unit area,the sandwich beam with a 20%volume fraction core layer had the best blast resistance.The filter radius has a slight effect on the shear stiffness and blast resistances of the sandwich beams.But increasing the filter radius could slightly improve the bending stiffness.Upon changing the initial PBC aspect ratio,there are three ways for PBC evolution:The first is to change the angle between the adjacent bars,the second is to further form holes in the bars,and the third is to combine the first two ways.However,not all three ways can improve the energy absorption capacity of the structure.Changing the aspect ratio of the PBC arbitrarily may lead to worse results.More studies are necessary for further detailed optimization.This research proposes a new topology sandwich beam structure by micro-topology optimization,which has sufficient shear stiffness.The micro mechanism of structural energy absorption is clarified,it is significant for structural energy absorption design.