Evaluation of corneal parameter changes under different accommodative stimuli with Scheimpflug imaging-based tomography

AIM:To evaluate the reliability of measurements of corneal changes with accommodation in healthy eyes using a Scheimpflug imaging-based system and how these measurements distribute in the normal population.METHODS:Prospective,non-randomized,comparative study including 27 healthy subjects(54 eyes),including emmetropia(13 eyes),myopia(17 eyes),hyperopia(4 eyes)and astigmatism(20 eyes)groups.In all cases,a complete eye examination was performed,including the analysis of corneal changes with different accommodative stimuli(+2.00,0.00 and-3.00 D)using the Pentacam AXL system.The investigation was structured in 2 phases:repeatability analysis and characterization of accommodation-related corneal changes in healthy populations.RESULTS:In the repeatability analysis,the index of height asymmetry(IHA)showed the greatest variability with the three accommodative stimuli,being the results for the rest of parameters acceptable.The group of emmetropes showed significant differences with accommodative changes in the position of maximum keratometry(Kmax;P<0.05),whereas in the astigmatism group,significant changes were not only observed in the position of Kmax,but also in minimum corneal thickness(MCT),corneal spherical aberration,and total and low order aberration root mean square(all P<0.05).Likewise,a significant difference was found in the displacement of the X position of Kmax with+2.00 D and-3.00 D in the myopia group(P=0.033)as well as in changes with+2.00 D and-3.00 D in the magnitude of the position vector of Kmax in the emmetropia group(P<0.05).No significant changes were found between accommodative stimuli in the displacement of coordinates of MCT(P≥0.109).CONCLUSION:The position of Kmax and MCT in healthy corneas can change significantly when presenting different accommodative stimuli using the accommodation mode of the Pentacam system,with different trends in these accommodation-related corneal changes between refractive errors.Likewise,the consistency of the measurements obtained with Scheimpflug has been confirmed.

江苏沭阳万北新石器时代遗址动物骨骼鉴定报告

南京博物院主持的省市考古工作队,在1987年、1988年三次试掘了江苏省沭阳县万匹乡的万北遗址,从新石器时代文化层中发掘出大量的动物遗骨,主要是若干种兽类的骨角材料.本文对已采集的大量标本进行了属种鉴定,对保存较好的代表性标本作简要的记述,并讨论若干问题,以供考古学和动物学的研究者参考.

钓鱼节上钓“大鱼”

由于小型养鱼者的异军突起,绐国营渔场造成巨大的市场冲击,使国营渔场举步维艰,收入每况愈下。而笔者前不久去邻县进行新闻采访时,获知这个县的—个国营渔场去年却大获丰收。

Direct linear discriminant analysis based on column pivoting QR decomposition and economic SVD

A direct linear discriminant analysis algorithm based on economic singular value decomposition （DLDA/ESVD） is proposed to address the computationally complex problem of the conventional DLDA algorithm, which directly uses ESVD to reduce dimension and extract eigenvectors corresponding to nonzero eigenvalues. Then a DLDA algorithm based on column pivoting orthogonal triangular （QR） decomposition and ESVD （DLDA/QR-ESVD） is proposed to improve the performance of the DLDA/ESVD algorithm by processing a high-dimensional low rank matrix, which uses column pivoting QR decomposition to reduce dimension and ESVD to extract eigenvectors corresponding to nonzero eigenvalues. The experimental results on ORL, FERET and YALE face databases show that the proposed two algorithms can achieve almost the same performance and outperform the conventional DLDA algorithm in terms of computational complexity and training time. In addition, the experimental results on random data matrices show that the DLDA/QR-ESVD algorithm achieves better performance than the DLDA/ESVD algorithm by processing high-dimensional low rank matrices.

Thyristor Controlled Phase Shifter:A Comprehensive Survey

Thyristor control phase shifter (TCPS) is one of the new facilities implemented in power network, leading to the development of economically efficient and technically reliable system. This paper introduces the function of TCPS in power system, describes its working principle and structure, and suggests some simple models used in its study and briefly presents the comparison between different types of TCPSs and their applications.

Effect of turf on the cutting movement of female football players

Purpose： The globalisation of artificial turf and the increase in player participation has driven the need to examine injury risk in the sport of football. The purpose of this study was to investigate the surface--player interaction in female football players between natural and artificial turf. Methods： Eight university level female football players performed an unanticipated cutting manoeuvre at an angle of 30° and 60°, on a regulation natural grass pitch （NT） and a 3G artificial turf pitch （AT）. An automated active maker system （CodaSport CXS System, 200 Hz） quantified 3D joint angles at the ankle and knee during the early deceleration phase of the cutting, defined from foot strike to weight acceptance at 20% of the stance phase. Differences were statistically examined using a two-way （cutting angle, surface） ANOVA, with an α level of p 〈 0.05 and Cohen＇s d effect size reported. Results： A trend was observed on the AT, with a reduction in knee valgus and internal rotation, suggesting a reduced risk of knee injury. This findings highlight that AT is no worse than NT and may have the potential to reduce the risk of knee injury. The ankle joint during foot strike showed large effects for an increase dorsiflexion and inversion on AT. A large effect for an increase during weight acceptance was observed for ankle inversion and external rotation on AT. Conclusion： These findings provide some support for the use of AT in female football, with no evidence to suggests that there is an increased risk of injury when performing on an artificial turf. The ankle response was less clear and further research is warranted. This initial study provides a platform for more detailed analysis, and highlights the importance of exploring the biomechanical changes in performance and injury risk with the introduction of AT.

Feasibility of replacing the 3-coach with a 1.5-coach grouping trainmodel in wind tunnel experiment at different yaw angles

The effects of different yaw angles on the aerodynamic performance of city electric multiple units(EMUs)were investigated in a wind tunnel using a 1:16.8 scaled model.Pressure scanning valve and six-component box-type aerodynamic balance were used to test the pressure distribution and aerodynamic force of the head car respectively from the 1.5-and 3-coach grouping city EMU models.Meanwhile,the effects of the yaw angles on the pressure distribution of the streamlined head as well as the aerodynamic forces of the train were analyzed.The experimental results showed that the pressure coefficient was the smallest at the maximum slope of the main shape-line.The side force coefficient and pressure coefficient along the head car cross-section were most affected by crosswind when the yaw angle was 55°,and replacing a 3-coach grouping with a 1.5-coach grouping had obvious advantages for wind tunnel testing when the yaw angle was within 24.2°.In addition,the relative errors of lift coefficient C_(L),roll moment coefficient C_(Mx),side force coefficient C_(S),and drag coefficient C_(D) between the 1.5-and 3-coach cases were below 5.95%,which all met the requirements of the experimental accuracy.

Biomechanical characteristics of an anterior cruciate ligament injury in javelin throwing

Purpose： The purpose of this study was to understand the mechanism of an anterior cruciate ligament （ACL） injury in javelin throwing and javelin throwing techniques relevant to this ACL injury. Methods： The patient in this study was an elite female javelin thrower who completed the first three trials and sustained a non-contact ACL injury on her left knee in the fourth trial of javelin throwing during a recent track and field meet. Three-dimensional kinematic data were collected in the injury and non-injury trials. The kinematic data of 52 male and 54 female elite javelin throwers were obtained from a javelin throwing biomechanical database. Results： The patient had greater forward center of mass velocity and less vertical center of mass velocity after the first 25% of the delivery phase in the injury trial compared to non-injury trials. The patient had less left knee flexion angle and angular velocity but similar left knee valgus and internal rotation angles during the first 21% of the delivery phase in the injury trial compared to non-injury trials. The video images showed an obvious tibia anterior translation at the 30% of the delivery phase in the injury trial. The left knee flexion angle and angular velocity at the time of the left foot landing and the maximal left knee flexion angle during the delivery phase were not significantly correlated to the official distance for 52 male and 54 female elite javelin throwers. Conclusion： The ACL injury in this study occurred during the first 30% of the delivery phase, most likely during the first 25% of the delivery phase. A stiff landing of the left leg with a small knee flexion angle was the primary contributor to this injury. Javelin throwers may have a soft left leg landing with a flexed knee, which may help them prevent ACL injuries without compromising performance.

A simple and robust method for essential boundary condition treatments in mesh-less methods

To improve the treatment efficiency of essential boundary condition in mesh-less methods, a simple and robust method is proposed in this paper. Rising weight of nodes in the construction of trail function, specified for essential boundary condition, can make the trail function pass through these nodes. And then, the trail function can satisfy the essential boundary condition previously by setting diagonal element to 1 or multiplying diagonal element by a big number in FEM. The MLS method is adopted to validate this method, and it is proved that this method is eostless and robust in most of mesh-less methods.

Effect of bolt inclination angle on shear behavior ofbolted joints under CNL and CNS conditions

Rock bolts are widely used in rock engineering projects to improve the shear capacity of the jointed rock mass.The bolt inclination angle with respect to the shear plane has a remarkable influence on the bolting performance.In this study,a new artificial molding method based on 3D scanning and printing technology was first proposed to prepare bolted joints with an inclined bolt.Then,the effects of the bolt inclination angle and boundary conditions on the shear behavior and failure characteristic of bolted joints were addressed by conducting direct shear tests under both CNL and CNS conditions.Results indicated that rock bolt could significantly improve the shear behavior of rock joints,especially in the post-yield deformation region.With the increase of bolt inclination angle,both the maximum shear stress and the maximum friction coefficient increased first and then decreased,while the maximum normal displacement decreased monotonously.Compared with CNL conditions,the maximum shear stress was larger,whereas the maximum normal displacement and friction coefficient were smaller under the CNS conditions.Furthermore,more asperity damage was observed under the CNS conditions due to the increased normal stress on the shear plane.

Description of a new species and the first instar larvae of Homidia(Collembola:Entomobryidae) from Taizhou,Zhejiang Province

A new species with four macrochaetae in the ＂eyebrow＂ of the anterior dorsal abdominal segment Ⅳ （Abd.Ⅳ）, Homidia quadriseta Pan sp. nov. is described fi＇om Zhejiang Province, eastern China. It can be discriminated from other recorded species in this genus by entire Abd. Ⅲ and posterior half Abd. IV darkly pigmented, 1 macrochaetae on medial Abd. Ⅲ, 2＋2 macrochaetae in ＂eyebrow＂ on anterior Abd. Ⅳ and 3 macrochaetae on posterior central Abd. Ⅳ, clypens with 12 chaetae, and fewer dental spines （7-8） on basal internal denes and with most spines slightly ciliated. Also, the chaetotaxy of the first instar of this new species is provided here.

BEAK-SHAPED GRAIN 1/TRIANGULAR HULL 1,a DUF640 gene,is associated with grain shape,size and weight in rice

Grain shape and size both determine grain weight and therefore crop yield. However, the molecular mechanisms controlling grain shape and size are still largely unknown. Here, we isolated a rice mutant, beak-shaped grain1 （bsgl）, which produced beak-shaped grains of decreased width, thickness and weight with a loosely interlocked lemma and palea that were unable to close tightly. Starch granules were also irregularly packaged in the bsgl grains. Consistent with the lemma and palea shapes, the outer parenchyma cell layers of these bsgl tissues developed fewer cells with decreased size. Map-based cloning revealed that BSG1 encoded a DUF640 domain protein, TRIANGULAR HULL 1, of unknown function. Quantitative PCR and GUS fusion reporter assays showed that BSG1 was expressed mainly in the young panicle and elongating stem. The BSG1 mutation affected the expression of genes potentially involved in the cell cycle and GW2, an important regulator of grain size in rice. Our results suggest that BSG1 determines grain shape and size probably by modifying cell division and expansion in the grain hull.

On-chip higher-order topological micromechanical metamaterials

Metamaterials with higher-order topological band gaps that exhibit topological physics beyond the bulkedge correspondence provide unique application values due to their ability of integrating topological boundary states at multiple dimensions in a single chip.On the other hand,in the past decade,micromechanical metamaterials are developing rapidly for various applications such as micro-piezoelectricgenerators,intelligent micro-systems,on-chip sensing and self-powered micro-systems.To empower these cutting-edge applications with topological manipulations of elastic waves,higher-order topological mechanical systems working at high frequencies(MHz)with high quality-factors are demanded.The current realizations of higher-order topological mechanical systems,however,are still limited to systems with large scales(centimetres)and low frequencies(k Hz).Here,we report the first experimental realization of an on-chip micromechanical metamaterial as the higher-order topological insulator for elastic waves at MHz.The higher-order topological phononic band gap is induced by the band inversion at the Brillouin zone corner which is achieved by configuring the orientations of the elliptic pillars etched on the silicon chip.With consistent experiments,theory and simulations,we demonstrate the emergence of coexisting topological edge and corner states in a single silicon chip as induced by the higher-order band topology.The experimental realization of on-chip micromechanical metamaterials with higherorder topology opens a new regime for materials and applications based on topological elastic waves.

Modeling complex crack problems using the three-node triangular element fitted to numerical manifold method with continuous nodal stress

A three-node triangular element fitted to numerical manifold method with continuous nodal stress, called Trig_3-CNS(NMM)element, was recently proposed for linear elastic continuous problems and linear elastic simple crack problems. The Trig_3-CNS(NMM) element can be considered as a development of both the Trig_3-CNS element and the numerical manifold method(NMM).Inheriting all the advantages of Trig_3-CNS element, calculations using Trig_3-CNS(NMM) element can obtain higher accuracy than Trig_3 element without extra degrees of freedom(DOFs) and yield continuous nodal stress without stress smoothing. Inheriting all the advantages of NMM, Trig_3-CNS(NMM) element can conveniently treat crack problems without deploying conforming mathematical mesh. In this paper,complex problems such as a crucifix crack and a star-shaped crack with many branches are studied to exhibit the advantageous features of the Trig_3-CNS(NMM) element. Numerical results show that the Trig_3-CNS(NMM) element is prominent in modeling complex crack problems.

Clinical study of reconstructing the medial malleolus with free grafting of fibular head composite tendon bone flap

Objective： To explore new surgical procedure for repairing and reconstructing medial malleolus and soft tissue defect. Methods： According to the size of medial malleolus and composite soft tissue defect, vascular fibular bead composite tendon bone flap free wafting using anterior tibial recurrent vessel as the perforating branch was designed to reconstruct the medial malleolar saddle and triangular ligament, and composite back broadest muscle flap free grafting was designed to repair the medical malleolar wound surface. From January 2000 to December 2006, the technique was used in 5 male patients who were injured by machine or in traffic accidents, causing bone and soft tissue defect. The size of wound surface ranged from 19 cm×12 cm to 24 cm×12 cm. Results： The wound surface was healed at the first stage in 4 cases, and the other case had infection and was cured in 6 months with anti infection therapy. Postoperative foUow-ups from 6 months to 6 years showed that grafted bones and free cutaneous flaps were healed well, malleolar joints were stable, joint movement was normal, and the appearance was satisfactory. The overall outcome was good. Conclusion ： Fibular head composite tendon bone flap free grafting is effective for repairing medical malleolar defect.

Effects of Electroacupuncture on Expression of COX-2 in the Dorsal Horn of Spinal Cord of Arthritic Rats

Objective： The present study was to observe the expression of COX-2 protein in the dorsal horn of the spinal cord in rats with chronic inflammatory pain to investigate whether COX-2 is involved in the mechanism of electroacupuncture （EA） analgesia. Methods： After EA treatment, the pain score and expression of COX-2 protein in the dorsal horn of spinal cord in rats with complete Freund＇s adjuvant （CFA）-induced arthritis were measured by the behavioral test and immunohistochemistry technique, and compared with those of the normal group, model group and medicine group. Results： EA could decrease the pain score significantly and repeated EA treatments had the remarkable cumulative analgesic effect; and with the increase in EA treatments, the number of COX-2 immunoreactive cells was obviously decreased. Conclusion： EA at acupoints Yanglingquan （GB 34） and Kunlun （BL 60） had remarkable analgesic effect on adjuvant arthritis rats; and in the meantime, could inhibit the expression of COX-2 protein in the dorsal horn of spinal cord.

Adaptive subdomain integration method for representing complex localized geometry in ANCF

In this work,we propose incorporating the finite cell method(FCM)into the absolute nodal coordinate formulation(ANCF)to improve the efficiency and robustness of ANCF elements in simulating structures with complex local features.In addition,an adaptive subdomain integration method based on a triangulation technique is devised to avoid excessive subdivisions,largely reducing the computational cost.Numerical examples demonstrate the effectiveness of the proposed method in large deformation,large rotation and dynamics simulation.

Spatial distribution, seasonal variation and regionalization of PM_(2.5) concentrations in China

In order to provide scientific support to policy makers in the regulation of PM2.5 pollution in China, it is important to accurately assess the current status, spatiotemporal characteristics and regionalization data for this air pollutant. An analysis of the pollution status of PM2.5 was conducted using daily averaged mass concentration data recorded in 74 cities in 2013 and 161 cities in 2014. The rotated empirical orthogonal function(REOF) method was applied to analyze this data. Results showed that the average annual PM2.5 concentration in urban areas of China is 62.2±21.5 ?g/m3, and that the distribution is spatially heterogeneous. The North China Plain, middle and lower Yangtze River Plain, Sichuan Basin and Guanzhong Plain had relatively high annual PM2.5 concentrations compared with the southeast coastal region, the Tibetan Plateau and the Yungui Plateau. PM2.5 mass concentrations tended to be higher in winter than in summer, however, the data for many cities showed a small peak in concentrations from May to July. An analysis of the spatial correlation of PM2.5 indicated a significant influence of topographic conditions. A lower correlation was observed where terrain features varied greatly. Based on the results of the REOF analysis and topographic characteristics, ten regions were identified in mid-eastern China, which could be considered as basic pollution prevention divisions for PM2.5; these include the North China Plain region, Pearl River Delta region, Jianghuai Plain region, middle Yangtze River Plain region, Northeast Plain region, Jiangnan coastal region, Sichuan Basin region, Qiantao Plain region, Guanzhong-Central Plain region and Yungui Plateau region. Seasonal variations in the regionalization data were observed, especially for the North China Plain and Pearl River Delta regions. Among the ten regions identified in this study, the North China Plain, Guanzhong-Central Plain, middle Yangtze River Plain and Jianghuai Plain had relatively high PM2.5 mass concentrations in comparison with the others. Therefore, these regions should be considered as the key regions to target in developing PM2.5 pollution prevention strategies. This study improves the present understanding of the spatial distribution, seasonal changes and regional status of PM2.5 pollution in China and helps establish possible control strategies for the reduction of this air pollutant.