Electro-Optically Switchable Optical True Delay Lines of Meter-Scale Lengths Fabricated on Lithium Niobate on Insulator Using Photolithography Assisted Chemo-Mechanical Etching

Optical true delay lines(OTDLs)of low propagation losses,small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications.Here,we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching.Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay.The fabricated OTLDs show an ultra-low propagation loss of^0.03dB/cm for waveguide lengths well above 100 cm.

Application of artificial intelligence in ophthalmology

Artificial intelligence is a general term that means to accomplish a task mainly by a computer, with the least human beings participation, and it is widely accepted as the invention of robots. With the development of this new technology, artificial intelligence has been one of the most influential information technology revolutions. We searched these English-language studies relative to ophthalmology published on PubMed and Springer databases. The application of artificial intelligence in ophthalmology mainly concentrates on the diseases with a high incidence, such as diabetic retinopathy, agerelated macular degeneration, glaucoma, retinopathy of prematurity, age-related or congenital cataract and few with retinal vein occlusion. According to the above studies, we conclude that the sensitivity of detection and accuracy for proliferative diabetic retinopathy ranged from 75% to 91.7%, for non-proliferative diabetic retinopathy ranged from 75% to 94.7%, for age-related macular degeneration it ranged from 75% to 100%, for retinopathy of prematurity ranged over 95%, for retinal vein occlusion just one study reported ranged over 97%, for glaucoma ranged 63.7% to 93.1%, and for cataract it achieved a more than 70% similarity against clinical grading.

Study on reaction characteristics of phenolic hydroxyl in coal by using the model compound during direct coal liquefaction

The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that tem- perature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.

Analysis of postoperative ocular surface changes and intervention effect after pars plana vitrectomy in meibomian gland dysfunction dry eye patients

AIM:To observe ocular surface changes after phacovitrectomy in patients with mild to moderate meibomian gland dysfunction(MGD)-type dry eye and track clinical treatment response using a Keratograph 5M and a Lipi View interferometer.METHODS:Forty cases were randomized into control group A and treatment group B;the latter received meibomian gland treatment 3d before phacovitrectomy and sodium hyaluronate before and after surgery.The average non-invasive tear film break-up time(NITBUTav),first noninvasive tear film break-up time(NITBUTf),non-invasive measured tear meniscus height(NTMH),meibomian gland loss(MGL),lipid layer thickness(LLT)and partial blink rate(PBR)were measured preoperatively and 1wk,1 and 3mo postoperatively.RESULTS:The NITBUTav values of group A at 1wk(4.38±0.47),1mo(6.76±0.70),and 3mo(7.25±0.68)were significantly lower than those of group B(7.45±0.78,10.46±0.97,and 11.31±0.89;P=0.002,0.004,and 0.001,respectively).The NTMH values of group B at 1wk(0.20±0.01)and 1mo(0.22±0.01)were markedly higher than those of group A(0.15±0.01 and 0.15±0.01;P=0.008 and P<0.001,respectively);however,there was no difference at 3mo.The LLT of group B at 3mo[91.5(76.25-100.00)]significantly exceeded that of group A[65.00(54.50-91.25),P=0.017].No obvious intergroup difference was found in MGL or PBR(P>0.05).CONCLUSION:Mild to moderate MGD dry eye worsens in the short term after phacovitrectomy.Preoperative cleaning,hot compresses,and meibomian gland massage as well as preoperative and postoperative sodium hyaluronate promote the rapid recovery of tear film stability.

腹腔镜胆总管探查术后一期缝合的疗效观察

目的探讨腹腔镜胆总管探查术(LCBDE)后一期缝合治疗合并急性胆管炎的胆总管结石患者的安全性和可行性。方法回顾性分析2015年1月-2020年8月合肥市第二人民医院108例在LCBDE后行一期缝合患者的临床资料。根据术前患者有无急性胆管炎分为有胆管炎组和无胆管炎组,对两组患者手术时间、术中出血量、术后拔管时间、术后住院时间和术后并发症等资料进行比较分析。结果两组患者均成功完成手术,无中转开腹病例,与无胆管炎组相比,有胆管炎组术中出血量较多,差异有统计学意义(P=0.010),两组患者手术时间、术后拔管时间、术后住院时间比较,差异均无统计学意义(P>0.05);两组患者术后并发症发生率比较,差异无统计学意义(P>0.05)。结论在遵循相关手术适应证的前提下,LCBDE后一期缝合治疗合并急性胆管炎的胆总管结石是安全可行的。

两种术式治疗重度上睑瘢痕性睑内翻的疗效比较

目的:比较显微镜下Hotz法联合睑缘切开皮瓣转位术和单纯Hotz法治疗重度上睑瘢痕性睑内翻的临床效果。方法:回顾性分析2017-07/2019-07在我院接受上睑内翻倒睫矫正术的患者60例84眼,试验组32例42眼采用显微镜下Hotz法联合睑缘切开皮瓣转位术,对照组28例42眼采用单纯Hotz法。术后随访观察至12mo,记录患者主观症状、睑缘位置、睫毛外翻情况及满意度。结果:试验组单眼平均手术时间长于对照组(40.8±2.57min vs 28.5±2.64min,P<0.01)。术后1、12mo,试验组治愈率分别为100%、95%,对照组治愈率分别为95%、76%,术后12mo试验组治愈率优于对照组(P=0.013)。术后1mo两组患者满意度无差异(Z=1.1825,P=0.2371),术后12mo试验组患者满意度高于对照组(Z=3.7346,P<0.01)。结论:对于重度上睑瘢痕性睑内翻,显微镜下Hotz法联合睑缘切开皮瓣转位术虽手术时间长于单纯Hotz法,但其远期疗效优于单纯Hotz法,术后12mo患者满意度较高。

不同黏弹剂对白内障超乳摘除及折叠IOL植入术后患者角膜内皮的影响

目的:分析双重黏弹剂DisCoVisc和透明质酸钠两种黏弹剂对白内障超声乳化摘除及折叠人工晶状体(IOL)植入术患者术后角膜内皮的影响。方法:选取2017-06/2019-12在荆门市爱尔眼科医院就诊的白内障患者247例285眼,按随机数字表法分DisCoVisc组(123例141眼)与透明质酸钠组(124例144眼)。两组均接受超声乳化摘除及折叠IOL植入术,DisCoVisc组术中使用DisCoVisc作为黏弹剂,透明质酸钠组术中使用1.7%透明质酸钠作为黏弹剂;比较两组术中超声乳化时间(UST)、累计释放能量(CDE)、植入IOL后抽吸黏弹剂的时间;术后1d, 1wk, 1、3mo时角膜水肿情况,术前、术后3mo时的角膜内皮细胞密度(ECD)及ECD损失率,角膜内皮细胞面积变异系数(CV)、角膜六角形内皮细胞比率(6A);术前,术后1d, 1wk, 1mo时的眼压、裸眼视力≥0.5的患者比例及中央角膜厚度(CCT)值。结果:两组UST、CDE、黏弹剂抽吸时间均无差异(P>0.05);两组术后1d时角膜水肿率无差异(P>0.05),术后1wk时角膜水肿均消失;术后3mo时DisCoVisc组ECD损失率显著低于透明质酸钠组(P<0.05);两组术前,术后1d, 1wk, 1mo时的眼压水平、裸眼视力≥0.5比例、CCT值均无差异(P>0.05)。结论:Emery-Little晶状体核硬度分级Ⅱ~Ⅲ级患者超声乳化摘除联合折叠IOL植入术中使用DisCoVisc作为黏弹剂对角膜内皮的保护作用更好。

Electroacupuncture induces acute changes in cerebral cortical mi RNA profile, improves cerebral blood flow and alleviates neurological deficits in a rat model of stroke

Electroacupuncture has been shown to improve cerebral blood flow in animal models of stroke. However, it is unclear whether electroacupuncture alters mi RNA expression in the cortex. In this study, we examined changes in the cerebral cortical mi RNA profile, cerebral blood flow and neurological function induced by electroacupuncture in a rat model of stroke. Electroacupuncture was performed at Renzhong（GV26） and Neiguan（PC6）, with a frequency of 2 Hz, continuous wave, current intensity of 3.0 m A, and stimulation time of 1 minute. Electroacupuncture increased cerebral blood flow and alleviated neurological impairment in the rats. mi RNA microarray profiling revealed that the vascular endothelial growth factor signaling pathway, which links cell proliferation with stroke, was most significantly affected by electroacupuncture. Electroacupuncture induced changes in expression of rno-mi R-206-3p, rno-mi R-3473, rno-mi R-6216 and rno-mi R-494-3p, and these changes were confirmed by quantitative real-time polymerase chain reaction. Our findings suggest that changes in cell proliferation-associated mi RNA expression induced by electroacupuncture might be associated with the improved cerebral blood supply and functional recovery following stroke.

胃镜协助气管插管在无痛内镜手术中的应用

目的研究胃镜协助气管插管在无痛内镜手术全身麻醉气管插管中的临床应用效果和优势。方法选取2018年1月-2019年12月该院收治的80例拟行内镜手术的全身麻醉气管插管患者,随机分成普通喉镜组(n=40)和胃镜协助组(n=40),普通喉镜组直接行气管插管,胃镜协助组采用胃镜协助的气管插管法。记录两组患者一次性插管成功率、气管插管时间、心血管事件及不良反应发生情况。结果胃镜协助组一次插管成功率明显高于普通喉镜组(97.50%和85.00%,P=0.048),气管插管时间明显短于普通喉镜组[(32.31±6.05)和(50.47±10.47)s,P=0.000]。与普通喉镜组相比,胃镜协助组的心血管事件发生率[平均动脉压(MAP)增高(2.6%和14.7%,P=0.029)、心动过速(5.1%和38.2%,P=0.000)]、并发症总发生率(5.1%和23.5%,P=0.023)较低;呛咳发生率为5.1%,术后未出现口咽部黏膜出血、门齿松动及声音嘶哑等并发症,两组比较,差异无统计学意义(P=0.303、P=0.125、P=0.281、P=0.281)。结论胃镜辅助气管插管在全身麻醉中应用效果良好,插管成功率较普通喉镜高,无需变换体位,且总体不良反应少,但需内镜人员协助完成,更适合在内镜中心推广。

Incomplete fluid-air exchange technique for idiopathic macular hole surgery

AIM: To explore an improved procedure involving incomplete fluid-air exchange for idiopathic macular hole(IMH), and the closure rate, visual function, and the visual field of macular holes(MHs) were evaluated.METHODS: This prospective randomized controlled study, included 40 eyes of 40 patients with IMH who were treated with pars plana vitrectomy and peeling of the internal limiting membrane. They were grouped by random digital table. Twenty-one eyes underwent incomplete fluidair exchange(IFA) and 19 eyes underwent traditional complete fluid-air exchange(CFA) as the control group. Outcomes included best-corrected visual acuity(BCVA), intraocular pressure, and optical coherence tomography, light adaptive electroretinography, and visual field evaluations.RESULTS: All MHs <400 μm were successfully closed. BCVAs before and 6 mo after surgery were 0.82±0.41 logMAR and 0.28±0.17 logMAR in IFA group and 0.86±0.34 logMAR and 0.34±0.23 logMAR in CFA group, respectively. The electroretinogram analysis of patients in IFA group revealed increases in b-wave amplitudes at 1, 3, and 6 mo after surgery. Additionally, patients in IFA group showed an amplitude increase of 28.6% from baseline at 6 mo(P<0.05), while no obvious improvements were noted in CFA group. Although there were no statistically significant improvements in either group, the IFA group showed a slight increase in mean sensitivity(P>0.05).CONCLUSION: IFA is a reliable method that offers comparable closure rate to CFA and facilitates improvements in visual function.

High-order numerical method for the derivative nonlinear Schrodinger equation

In this work,a fourth-order numerical scheme in space and two second-order numerical schemes in both time and space are proposed for the derivative nonlinear Schrodinger equation.We verify the mass conservation for the two-level implicit scheme.The influence on the soliton solution by adding a small random perturbation to the initial condition is discussed.The numerical experiments are given to test the accuracy order for different schemes,respectively.We also test the conservative property of mass and Hamiltonian for these schemes from the numerical point of view.

Hot Corrosion Behavior of SiO_2–Al_2O_3–Glass Composite Coating on Ti–47Al–2Cr–2Nb Alloy: Diffusion Barrier for S and Cl

Type Ⅰ hot corrosion behavior of SiO_2-Al_2O_3-glass composite coating based on Ti-47 Al-2 Cr-2 Nb substrate was investigated in the mixture salt of 25 wt%NaCl + 75 wt%Na_2SO_4 at 850 °C. The results showed that there was a bidirectional ion exchange between composite coating and the film of mixed salts, and the sodium ion in the molten salts penetrated into the glass matrix of composite coating, while the potassium ion in the glass matrix dissolved into the molten salts. A decrease in hot corrosion rate was achieved for the coated alloy in comparison with the bared substrate due to the composite coating acting as a diffusion barrier to sulfur and chlorine and preventing the molten salts from diffusing to the coating/alloy interface during the hot corrosion exposure. Additionally, the composite coating decreased the oxygen partial pressure at the coating/alloy interface and promoted the selective oxidation of Al to form a protective Al_2O_3 layer.

Mechanical and tribological properties of graphene nanoplatelets-reinforced titanium composites fabricated by powder metallurgy

Titanium matrix composite reinforced by graphene nanoplatelets(GNPs)was fabricated via powder metallurgy route.Hot isostatic pressing and hot extrusion were used to consolidate the mixed powder of GNPs and TC4 titanium(Ti)alloy.The microstructures,mechanical properties and sliding wear performance of Ti/GNPs composite had been researched to evaluate the rein forcing effect of GNPs on tita nium matrix.Microstructure observation indicates that GNPs could restrain grai n growth slightly in titanium matrix.Titanium matrix and graphene exhibit a clean and firm interface formed by means of metallurgical bonding on atomic scale.Compared with the monolithic titanium alloy,the composite with 1.2 vol.%GNPs exhibits significantly improved elastic modulus and strength.The sliding wear test shows that there is an obvious enhancement in the tribological performance of Ti/GNPs composite with 1.2 vol.%GNPs.The results of this work indicate that GNP is an efficient reinforcenient material in titanium matrix.The strengthening mechanism including precipitates strengthening,load transfer and grain refinement mechanism of GNPs in titanium matrix was discussed.A modified shear-lag model was used to analyze the reinforcement contribution of the stress transfer mechanism.The calculation shows that the stress load mechanism constitutes the main strengthening mechanism in Ti/GNPs composite.

Aggregation-induced phosphorescence and mechanochromic luminescence of a tetraphenylethene-based gold(Ⅰ) isocyanide complex

In this study,a new twisting gold（Ⅰ） isocyanide complex based on tetraphenylethene（TPE）,TPE-NC-Au.was designed and synthesized.It exhibits aggregation induced phosphorescence（AIP） characteristics,owing to the incorporation of Au moiety and conformation rigidification in the aggregated states.Moreover,the emission color of the crystalline solid of TPE-NC-Au changes from blue（454 nm） to green（500 nm） in response to mechanical grinding,due to the combined effects of conformation planarization,enhanced π…π stacking,as well as the emergence of aurophilic interactions in the ground amorphous state.Notably,the emission color can be restored upon solvent fuming,associating with the reconstruction of crystalline lattices.The AIP and switchable mechanochromism of TPE-NC-Au make it suitable for potential applications in bioimaging,sensing,and optoelectronic devices.

Exploiting Multiple Correlations Among Urban Regions for Crowd Flow Prediction

Crowd flow prediction has become a strategically important task in urban computing,which is the prerequisite for traffic management,urban planning and public safety.However,due to variousness of crowd flows,multiple hidden correlations among urban regions affect the flows.Besides,crowd flows are also influenced by the distribution of Points-of-Interests(POIs),transitional functional zones,environmental climate,and different time slots of the dynamic urban environment.Thus,we exploit multiple correlations between urban regions by considering the mentioned factors comprehensively rather than the geographical distance and propose multi-graph convolution gated recurrent units(MGCGRU)for capturing these multiple spatial correlations.For adapting to the dynamic mobile data,we leverage multiple spatial correlations and the temporal dependency to build an urban flow prediction framework that uses only a little recent data as the input but can mine rich internal modes.Hence,the framework can mitigate the influence of the instability of data distributions in highly dynamic environments for prediction.The experimental results on two real-world datasets in Shanghai show that our model is superior to state-of-the-art methods for crowd flow prediction.