In vivo pilot study into superficial microcirculatory characteristics of colorectal adenomas using novel high-resolution magnifying endoscopy with blue laser imaging

BACKGROUND No studies have yet been conducted on changes in microcirculatory hemody-namics of colorectal adenomas in vivo under endoscopy.The microcirculation of the colorectal adenoma could be observed in vivo by a novel high-resolution magnification endoscopy with blue laser imaging(BLI),thus providing a new insight into the microcirculation of early colon tumors.AIM To observe the superficial microcirculation of colorectal adenomas using the novel magnifying colonoscope with BLI and quantitatively analyzed the changes in hemodynamic parameters.METHODS From October 2019 to January 2020,11 patients were screened for colon adenomas with the novel high-resolution magnification endoscope with BLI.Video images were recorded and processed with Adobe Premiere,Adobe Photoshop and Image-pro Plus software.Four microcirculation parameters:Microcirculation vessel density(MVD),mean vessel width(MVW)with width standard deviation(WSD),and blood flow velocity(BFV),were calculated for adenomas and the surrounding normal mucosa.RESULTS A total of 16 adenomas were identified.Compared with the normal surrounding mucosa,the superficial vessel density in the adenomas was decreased(MVD:0.95±0.18 vs 1.17±0.28μm/μm2,P<0.05).MVW(5.11±1.19 vs 4.16±0.76μm,P<0.05)and WSD(11.94±3.44 vs 9.04±3.74,P<0.05)were both increased.BFV slowed in the adenomas(709.74±213.28 vs 1256.51±383.31μm/s,P<0.05).CONCLUSION The novel high-resolution magnification endoscope with BLI can be used for in vivo study of adenoma superficial microcirculation.Superficial vessel density was decreased,more irregular,with slower blood flow.

White light endoscopy,narrow band imaging and chromoendoscopy with magnification in diagnosing colorectal neoplasia

AIM:To evaluate the sensitivity(Sn),specificity(Sp),positive predictive value(PPV) and negative predictive value(NPV) of 3 different techniques:high resolution white light endoscopy(WLE),Narrow Band Imaging(NBI) and Chromoendoscopy(CHR),all with magnification in differentiating adenocarcinomas,adenomatous and hyperplastic colorectal polyps.METHODS:Each polyp was sequentially assessed first by WLE,followed by NBI and finally by CHR.Digital images of each polyp with each modality were taken and stored.Biopsies or polypectomies were then performed followed by blinded histopathological analysis.Each image was blindly graded based on the Kudo's pit pattern(KPP).In the assessment with NBI,the mesh brown capillary network pattern(MBCN) of each polyp was also described.The Sn,Sp,PPV and NPV of differentiating hyperplastic(Type Ⅰ & Ⅱ-KPP,Type Ⅰ-MBCN) adenomatous(Types Ⅲ,Ⅳ-KPP,Type Ⅱ-MBCN) and carcinomatous polyps(Type Ⅴ-KPP,Type Ⅲ-MCBN) was then compared with reference to the final histopathological diagnosis.RESULTS:A total of 50 colorectal polyps(5 adenocarcinomas,38 adenomas,7 hyperplastic) were assessed.CHR and NBI [KPP,MBCN or the combined classification(KPP & MBCN)] were superior to WLE in the prediction of polyp histology(P < 0.001,P=0.002,P=0.001 and P < 0.001,respectively).NBI,using the MBCN pattern or the combined classification showed higher numerical accuracies compared to CHR,but this was not statistically significant(P=0.625,0.250).CONCLUSION:This feasibility study demonstrated that this combined classification with NBI could potentially be useful in routine clinical practice,allowing the endoscopist to predict histology with higher accuracies using a less cumbersome and technically less challenging method.

Polyp detection rates using magnification with narrow band imaging and white light

AIM: To compare the yield of adenomas between narrow band imaging and white light when using high definition/magnification. METHODS: This prospective, non-randomized comparative study was performed at the endoscopy unit of veteran affairs medical center in Phoenix, Arizona. Consecutive patients undergoing first average risk colorectal cancer screening colonoscopy were selected. Two experienced gastroenterologists performed all the procedures that were blinded to each other's findings. Demographic details were recorded. Data are presented as mean ± SEM. Proportional data were compared using the χ2 test and means were compared using the Student's t test. Tandem colonoscopy was performed in a sequential and segmental fashion using one of 3 strategies: white light followed by narrow band imaging [Group A: white light(WL) → narrow band imaging(NBI)]; narrow band imaging followed by white light(Group B: NBI → WL) and, white light followed by white light(Group C: WL → WL). Detection rate of missed polyps and adenomas were evaluated in all three groups. RESULTS: Three hundred patients were studied(100 in each Group). Although the total time for the colonoscopy was similar in the 3 groups(23.8 ± 0.7, 22.2 ± 0.5 and 24.1 ± 0.7 min for Groups A, B and C, respectively), it reached statistical significance between Groups B and C(P < 0.05). The cecal intubation time in Groups B and C was longer than for Group A(6.5 ± 0.4 min and 6.5 ± 0.4 min vs 4.9 ± 0.3 min; P < 0.05). The withdrawal time for Groups A and C was longer than Group B(18.9 ± 0.7 min and 17.6 ± 0.6min vs 15.7 ± 0.4 min; P < 0.05). Overall miss rate for polyps and adenomas detected in three groups during the second look was 18% and 17%, respectively(P = NS). Detection rate for polyps and adenomas after first look with white light was similar irrespective of the light used during the second look(WL → WL: 13.7% for polyps, 12.6% for adenomas; WL → NBI: 14.2% for polyps, 11.3% for adenomas). Miss rate of polyps and adenomas however was significantly higher when NBI was used first(29.3% and 30.3%, respectively; P < 0.05). Most missed adenomas were ≤ 5 mm in size. There was only one advanced neoplasia(defined by size only) missed during the first look. CONCLUSION: Our data suggest that the tandem nature of the procedure rather than the optical techniques was associated with the detection of additional polyps' and adenomas.

Ultra high magnification endoscopy: Is seeing really believing?

Endoscopy is an indispensible diagnostic and thera-peutic instrument for gastrointestinal diseases. Endo-cytoscopy and confocal endomicroscopy are two types of ultra high magnification endoscopy techniques.Standard endoscopy allows for 50 × magnification,whereas endocytoscopy can magnify up to 1400 × and confocal endomicroscopy can magnify up to 1000 ×.These methods open the realm of real time micros copicevaluation of the GI tract, including cellular and subcellular structures. Confocal endomicroscopy has the additional advantage of being able to visualize subsurface structures. The use of high magnification endoscopy inconjunction with standard endoscopy allows for a real-time microscopic assessment of areas with macroscopic abnormalities, providing "virtual biopsies" with valuable information about cellular and subcellular changes. Thiscan minimize the number of biopsies taken at the time of endoscopy. The use of this technology may assistin detecting premalignant or malignant changes at anearlier state, allowing for earlier intervention and treatment. High magnification endoscopy has shown promising results in clinical trials for Barrett's esophagus,esophageal adenocarcinoma, esophageal squamous cell cancer, gastric cancer, celiac disease, colorectalcancer, and inflammatory bowel disease. As the use of high magnification endoscopy techniques increases,the clinical applications will increase as well. Of the two systems, only confocal endomicroscopy is currently commercially available. Like all new technologies there will be an initial learning curve before operators become proficient in obtaining high quality images and discerning abnormal from normal pathology. Validatedcriteria for the diagnosis of the various gastrointestinal diseases will need to be developed for each method. Inthis review, the basic principles of both modalities are discussed, along with their clinical applic ability and limitations.

Experimental study on dynamic load magnification factor for ballastless track-subgrade of high-speed railway

The magnitude of dynamic load produced by high-speed trains depends on many factors,of which train speed is the most critical one.However,it is quite difficult to determine the effect of train speed on dynamic load using the theoretical methods due to the complexity of the interaction between vehicle and track-subgrade.Thus large-scale model test has gradually become an important approach for studying dynamic responses of ballastless track-subgrade of high-speed railway.In this study,a full-scale model of ballastless track-subgrade was constructed in accordance with the design and construction standards for Shanghai-Nanjing intercity high-speed railway line firstly.Then,the dynamic strain of slab and the dynamic earth pressure of subgrade were measured by conducting single wheel axle excitation test.In addition,the relationship between the dynamic load magnification factor（DLF） and the train speed was obtained.Finally,the DLF of track-subgrade under different train speeds was proposed,similar to that given by German Railway Standard.

Diagnosis of autoimmune gastritis by high resolution magnification endoscopy

胃的萎缩的内视镜的可视化通常不与常规内视镜检查法是可行的。放大内视镜检查法是有用的分析潜水艇没有织物的上皮的微脉管的建筑学以及粘膜表面微观结构活体检视。用这种技术，我们能描述正常胃的微脉管系统模式，我们也在自体免疫的萎缩性胃炎的二种情况中识别了典型模式。

AN IMAGE MAGNIFICATION ALGORITHM USING THE GVF CONSTRAINT MODEL

An image magnification method with a Gradient Vector Flow(GVF)constraint-basedanisotropic diffusion model is proposed in this letter.A Low-Resolution(LR)image is first magnifiedusing bilinear interpolation,and then an iterative image restoration method,with the use of an ani-sotropic diffusion model and a Gaussian moving-average constraint,is applied to the magnified image.The estimated GVF of a High-Resolution(HR)image can be used to remove the jagged effect and topreserve the textural structure in the image.Meanwhile,the use of the Gaussian moving-average LRmodel can provide a data fidelity constraint,which renders a magnified image closer to the ideal HRversion.Experimental results show that the proposed method can improve the quality of magnifiedimages in terms of both objective and subjective criteria.

Studying the depth-dependent variation of site magnification factor in Dongchuan by earthquakes observed in borehole

The digital seismometers with high accuracy are installed at depths of -200 m, -100 m in borehole and on the surface in Dongchuan. By analysis of spectra ratio, the local events (with epicentral distances between 8.5 km and 95 km, magnitudes ML = 1.3-5.1) recorded are used to calculate site magnification factor at different depths (-100 m and surface) in Dongchuan. Comparing results with that at the depth of -200 m, the site magnification factors at three components of N-S, E-W and U-D corresponding to the depth of -100 m at 8 frequencies (f = 0.75, 1.0, 1.5, 2, 3, 4, 6, and 12 Hz) are 1.0-1.49 when 0.75 Hz- [less-than or equal to] f [less-than or equal to] 2 Hz and 0.47-0.99 when 2 Hz less than or equal f less than or equal 12 Hz. On the surface, site magnification factors at three components are all greater than 1, i.e. between 1.6 and 7.63. The correlation coefficients of site magnification factors for S wave and coda at the depth of -100 m and on surface are 0.82 and 0.81 when 0.75 Hz [less-than or equal to] f [less-than or equal to] 2 Hz, 0.47 and 0.45 when 2 Hz less than or equal f less than or equal 12 Hz, respectively.

Achieving thermal magnification by using effective thermal conductivity

thermal magnification device is proposed by using effective thermal conductivity. Different fromtransformation optics method, the magnification design is realized analytically by enforcingequality of effective thermal conductivity on the magnification device and the reference case inspecified domains. The validity of theoretical analysis is checked by numerical simulation results,which demonstrates the magnifying effects of the proposed design. The device only needsisotropic and homogeneous materials that are easy to obtain in nature. It is also shown that theobtained magnifying conditions are the same as those derived by separation of variables. But theproposed method proves more flexible for multilayered materials and simpler for non-sphericalobjects under non-uniform thermal fields. It can also be extended to other fields and applicationsgoverned by Laplace equation.

Russell body gastritis with Dutcher bodies evaluated using magnification endoscopy

Russell body gastritis(RBG) is an unusual type of chronic gastritis characterized by marked infiltration of Mott cells,which are plasma cells filled with spherical eosinophilic bodies referred to as Russell bodies.It was initially thought that Helicobacter pylori(H.pylori) infection was a major cause of RBG and that the infiltrating Mott cells were polyphenotypic;however,a number of cases of RBG without H.pylori infection or with monoclonal Mott cells have been reported.Thus,diagnostic difficulty exists in distinguishing RBG with monoclonal Mott cells from malignant lymphoma.Here,we report an unusual case of an 86-year-old-Japanese man with H.pylori-positive RBG.During the examination of melena,endoscopic evaluation confirmed a 13-mm whitish,flat lesion in the gastric antrum.Magnification endoscopy with narrowband imaging suggested that the lesion was most likely a poorly differentiated adenocarcinoma.Biopsy findings were consistent with chronic gastritis with many Mott cells with intranuclear inclusions referred to as Dutcher bodies.Endoscopic submucosal dissection confirmed the diagnosis of RBG with kappa-restricted monoclonal Mott cells.Malignant lymphoma was unlikely given the paucity of cytological atypia and Ki-67 immunoreactivity of monoclonal Mott cells.This is the first reported case of RBG with endoscopic diagnosis of malignant tumor and the presence of Dutcher bodies.

Variations of OCT measurements corrected for the magnification effect according to axial length and refractive error in children

Purpose:The aim of this paper was to examine the distribution of macular,retinal nerve fiber layer(RNFL)thickness and optic disc parameters of myopic and hyperopic eyes in comparison withemmetropic control eyes and to investigate their variation according to axial length(AL)andspherical equivalent(SE)in healthy children.Methods:This study included 293 pairs of eyes of 293children(145 boys and 148 girks),ranging in age from 6 to 17 years,Subjects were dividedaccording to SE in control(emmetropia,99 children),myopia(100 children)and hyperopia(94children)groups and according to axial AL in 68 short(<22.00 mm,68),medium(from≥22.00 mmto 25.00 mm,189)and long eyes(>25.00 mm,36).Macular parameters,RNFL thickness and opticdisc morphology were assessed by the Cirrus^(TM) HD-OCT.AL was measured using the IOL-Mastersystem.Littmann's formula was used for calculating the corrected AL-related ocular magnification.Results Mean age(±SD)was 10.84±3.05 years;mean(±SD)SE was+0.14±0.51 D(range from8.75 to+8.25 D)and mean AL(±SD)was 23.12±1.49.Average RNFL thickness,averagemacular thickness and macular volume decreased as AL and myopia increased.No correlationsbetween AL/SE and optic disc parameters were found after correcting for magnification effect.Conclusions:AL and refractive error affect measurements of macular and RNFL thickness inhealthy children.To make a correct interpretation of ocT measurements,ocular magnificationeffect should be taken into account by clinicians or OCT manufacturers.

Experimental Modal Damping Identification of a Mechanical Structure Using Video Magnification Technique

Vibration can be introduced in all mechanical fields in our life.Engineers try to avoid its negative effect leading in some cases to deformation in the machines.Many researches are dedicated to study the identification of damping especially in multi degree of freedom systems with particular attention to the source of energy dissipation.They focus on developing new tools or methods which may be used in real problems to obtain accurate results about the amount(or value)and the location of energy dissipation in the structure.The aim of this paper is to present an original procedure aims to experimentally determine the modal damping ratio of a mechanical structure.The proposed procedure consists of extracting the Frequency Response Function of the vibrating system using the video magnification method and then calculate the modal damping ratio using the 3-dB method.These experimental measurements are carried out by giving an external force on a cantilever beam,then the modal damping ratios are extracted using motion magnification.The obtained results show a relative error less than 4.2% between the experimental measurements and the analytical calculation for the Frequency Response Function(FRF)curves.The novelty of the paper is to combine the video magnification technique and the 3dB method in a procedure that aims to experimentally measure the modal damping of a mechanical structure.The proposed procedure in this paper represents the damping identification as a simple and easy engineering application.

Web-based system for training and dissemination of a magnification chromoendoscopy classification

AIM:To evaluate the use of web-based technologies to assess the learning curve and reassess reproducibility of a simplified version of a classification for gastric magnification chromoendoscopy (MC). METHODS: As part of a multicenter trial, a hybrid approach was taken using a CD-ROM, with 20 films of MC lasting 5 s each and an "autorun" file triggering a local HTML frameset referenced to a remote questionnaire through an Internet connection. Three endoscopists were asked to prospectively and independently classify 10 of these films randomly selected with at least 3 d apart. The answers were centrally stored and returned to participants together with adequate feedback with the right answer. RESULTS: For classification in 3 groups, both intra- [Cohen's kappa (κ) = 0.79-1.00 to 0.89-1.00] and inter-observer agreement increased from 1st (moderate) to 6th observation (κ = 0.94). Also, agreement with reference increased in the last observations (0.90, 1.00 and 1.00, for observers A, B and C, respectively). Validity of 100% was obtained by all observers at their 4th observation. When a 4th (sub)group was considered, inter-observer agreement was almost perfect (κ=0.92) at 6th observation. The relation with reference clearly improved into κ (0.93-1.00) and sensitivity (75%-100%) at their 6th observations. CONCLUSION: This MC classification seems to be easily explainable and learnable as shown by excellent intra-and inter-observer agreement, and improved agreement with reference. A web system such as the one used in this study may be useful for endoscopic or other image based diagnostic procedures with respect to definition, education and dissemination.

A method to estimate gas magnification of multi-gap resistive plate chamber

The gas magnification of multi-gap resistive plate chamber (MRPC) is very difficult to be measured using the present instruments thoroughly in the world. The gas magnifications about ~107 were obtained in the various operation-high-voltages of multi-gap resistive plate chamber (MRPC) by means of Monte-Carlo simulation and the presented experiment method.

High Optical Magnification Three-Dimensional Integral Imaging of Biological Micro-organism

A high optical magnification three-dimensional imaging system is proposed using an optic microscope whose ocular （eyepiece） is retained and the structure of the transmission mode is not destroyed. The elemental image array is captured through the micro lens array. Due to the front diffuse transmission element, each micro lens sees a slightly different spatial perspective of the scene, and a different independent image is formed in each micro lens channel. Each micro lens channel is imaged by a Fourier lens and captured by a CCD. The design translating the stage in x or y provides no parallax. Compared with the conventional integral imaging of micro-objects, the optical magnification of micro-objects in the proposed system can enhanced remarkably. The principle of the enhancement of the image depth is explained in detail and the experimental results are presented.

Fatigue Magnification Factors of Arc-Soft-Toe Bracket Joints

Arc-soft-toe bracket(ASTB), as a joint structure in the marine structure, is the hot spot with significant stress concentration, therefore, fatigue behavior of ASTBs is an important point of concern in their design. Since macroscopic geometric factors obviously influence the stress flaws in joints, the shapes and sizes of ASTBs should represent the stress distribution around cracks in the hot spots. In this paper, we introduce a geometric magnification factor for reflecting the macroscopic geometric effects of ASTB crack features and construct a 3D finite element model to simulate the distribution of stress intensity factor(SIF) at the crack endings. Sensitivity analyses with respect to the geometric ratio Ht/Lb, R/Lb, Lt/Lb are performed, and the relations between the geometric factor and these parameters are presented. A set of parametric equations with respect to the geometric magnification factor is obtained using a curve fitting technique. A nonlinear relationship exists between the SIF and the ratio of ASTB arm to toe length. When the ratio of ASTB arm to toe length reaches a marginal value, the SIF of crack at the ASTB toe is not influenced by ASTB geometric parameters. In addition, the arc shape of the ASTB slope edge can transform the stress flowing path, which significantly affects the SIF at the ASTB toe. A proper method to reduce stress concentration is setting a slope edge arc size equal to the ASTB arm length.

High Accuracy Zoom Magnification Measurement

A precise zoom magnification is important for semiconductor industry and biomedical research. A novel measurement method is demonstrated for optical zoom magnification measurement in this paper. The magnification is obtained by pattern correction between barcode image formed by optical zoom and reference image generated by an ideal optical model. Measurement accuracy which is better than 0.06% has been achieved for optical zoom magnification. Compared with traditional concept, the measurement results are only dependent on two line edges. The barcode correlation method can achieve higher accuracy and better robustness by using the information over the whole field of view.

一种摆式谐振加速度计的微杠杆结构设计与分析

为提升摆式谐振式加速度计性能,设计了一种将质量块与微杠杆结构一体化的摆式微杠杆结构,实现惯性力的敏感与放大,提升结构的鲁棒性。首先建立了微杠杆结构力学模型,并进行了关键参数计算。其次,根据微杠杆结构放大倍数影响机理,分析了质量块、支撑梁及微杠杆结构尺寸参数对放大倍数的影响;理论分析与有限元仿真结果均表明,支点梁与输出梁的宽度应作为该类微杠杆的关键优化参数。最后,根据上述结论对现有结构尺寸进行优化,优化后的微杠杆放大倍数为15.68,系统放大倍数为12.88,标度因数为70.52 Hz/g,较优化前分别提升了36.94%、36.87%和36.88%,验证了优化方法的有效性。

高能激光光束质量β因子测量方法

高能激光光束质量β因子测量装置主要用于强激光系统状态调试和综合性能参数诊断,用于评价激光系统出光性能以及远场光斑可聚焦的能力。针对接近衍射极限光束质量β因子测量过程中被测光斑在面阵相机上所占的像素点太少等缺陷,研究了采用聚焦显微放大与高精度扫描狭缝相结合的光束质量β因子测量方法,并对相关方案进行了分析计算。此外还设计了采用固定像差元件及平行光管光源组合的激光光束质量β因子测量结果验证方案,对研制的高能激光光束质量β因子测量装置进行了不确定度分析,测量不确定度优于10%。

基于视频的振动测量技术研究进展

振动测量是保障结构安全和良好状态的基本手段。高精度的振动测量可为结构设计、安装调试、健康管理等振动试验提供精确的输入与响应测试。相较于传统的振动测量手段,基于视频的振动测量技术将相机的全部像素转化为高精度振动传感器,利用视频图像方式让人们肉眼可视结构在物理世界的真实振动形态,具有非接触、全视场、高空间分辨率、灵活方便等优点,近年来受到业界的广泛关注。该文主要介绍了视频振动测量技术的系统构成与测量过程、当前主要方法和相关技术最新进展,并总结了视频振动测量技术与其他技术相比存在的优势。通过分析与对比,肯定了视频方法是解决振动测量问题的有效手段和对传统测量方法的有力补充,随着相关技术和硬件设备的发展,视频振动测量方法将具有越来越大的研究意义和应用价值。