分核器劈核在白内障超声乳化术中的应用

目的在白内障超声乳化中采用一种新型劈核方法-分核器机械劈核代替常规超声劈核,以此降低术中超声能量使用、缩短超声时间和减少灌注液的使用,从而达到保护角膜内皮细胞和降低手术并发症的目的。方法采用分核器机械劈核(实验组)与常规超声劈核(对照组)进行对比。各组选择病例100例(Ⅱ级核50例,Ⅲ级核50例),记录手术中使用超声能量和超声时间进行比较,观察术后第2天角膜内皮细胞和角膜基质细胞形态改变。结果实验组和对照组比较:(1)实验组超声时间平均每例降低9.04 s,有显著差异(P=0.009);(2)实验组超声能量平均每例降低1.74,有显著差异(P=0.001);(3)实验组术后第2天角膜内皮细胞和基质细胞形态改变明显好于对照组。结论使用分核器机械劈核代替目前的超声劈核技术,操作更简单,可以明显减少超声对角膜内皮细胞的损伤,降低手术并发症,达到白内障超声乳化手术微创目的。

垂直式分核器在小切口非超声乳化白内障摘除术中的应用

目的评价一种垂直式分核器在小切口非超声乳化白内障摘除术中的作用。方法120例(120眼)在我院接受白内障扫盲手术者随机分为两组,对照组(n=60)采用不分核的小切口非超声乳化白内障摘除术,观察组(n=60)在小切口非超声乳化白内障摘除术中应用了垂直式分核器进行分核,分别观察两组的并发症及术后3个月的视力及散光度。结果术后3个月对照组视力0.5以上者为11例(18.3%),观察组0.5以上视力者33例(55.0%),两组比较差异有统计学意义(P<0.01)。观察组术后散光为(1.04±0.55)D,明显低于对照组的(1.93±1.06)D(P<0.01)。两组的并发症均少。结论垂直式分核器是一种有效可行的手术方法。

Visualization of the Precessing Vortex Core in a Cyclone Separator by PIV

The precessing vortex core (PVC) in a cyclone separator plays an important role in the separation performance and in further understanding of the general law of periodic unsteady flow therein. In this paper, the unsteady flow field is investigated with particle image velocimetry (PIV), and the instantaneous velocity, vorticity, tangential velocity, and radial velocity are acquired by analyzing the images of instantaneous flow. It is for the first time reported that there is a centrifugal flow region close to the dust discharge zone and its maximum value is higher than the mean radial velocity. This discovery is very important for understanding the principle of separation of particles in the area of dust discharge. Determination of the frequency and amplitude of PVC was conducted in the region where the phenomenon of PVC is remarkable. Results agree well with those obtained by hot wire anemometry. The observations of the center of vortex core and the bimodal distribution of the amplitude of the PVC indicate the vortex core precesses around the geometric axis of the cyclone in its own way.

Molecular Cloning of PhoR Sensor Domain from Mycobacterium tuberculosis for Structure-Based Discovery of Novel Anti-Tubercular

The emergence of multidrug-resistant strains （MDR-TB） and extensively drug-resistant strains （XDR-TB） has fuelled the quest for novel drugs and drug targets for its successful treatment. One of the potential candidates as novel TB drug target is the PhoR sensor domain, an extracellular domain of PhoR histidine kinase. PhoR sensor domain is part of the two-component system PhoR-PhoP that senses environmental stimuli and relays the signal to control the expression of 78 virulent associated genes in Mycobacterium tuberculosis. 3D structure of the PhoR sensor domain will facilitate the structure based drug discovery of novel anti- tubercular. In this study, we successfully predicted and isolated the gene encoding PhoR sensor domain from Mycobacterium tuberculosis H37Rv, cloned it in pGEM-T vector and subcloned it in pRSET emGFP expression vector. PhoR sensor domain was successfully cloned and would be used for further expression, purification and crystallization studies.

Performance Analysis of Integrative QoS Scheme for Routers

This paper proposes an integrative scheme of DiffServ （differentiated service） for the IP-based network. In the scheme, QoS （Quality of Service） is ranked according to the level of both the queuing delay and the drop precedence that base on the relative differentiated service; it does not take the resource reservation problem into consideration for making its implementation more simple and flexible. We will propose an implemented architecture including edge routers and core routers, and the PHB （per-hop-behavior） architecture of the routers is generalized. We adopt ERED （extended random early discard） mechanism for drop precedence and use proportional delay differentiation for queuing delay. In the proportional delay differentiation topic, we propose a new WTP （waiting time priority）-like algorithm. Besides, a new stochastic petri net model of the PHB model is given, and the performance of whole implemented PHB architecture is analyzed, too.

Progress of pyrene-based organic semiconductor in organic field effect transistors

Thanks to the pure blue emitting, high planarity, electron rich and ease of chemical modification, pyrene has been thoroughly investigated for applications in organic electronics such as organic light emitting diodes(OLEDs), organic field effect transistors(OFETs), and organic solar cells(OSCs). Especially, great progresses have been made of pyrene-based organic semiconductors for OFETs in past decades. Due to the difference of molecular structure, pyrene-based organic semiconductors are divided into three categories, pyrene as terminal group, pyrene as center core and fused pyrene derivatives. This minireview gives a brief introduction of the structure-property relationship and application in OFETs about most of pyrene-based semiconducting materials since 2006,illustrating that pyrene is a good building block to construct semiconductors with superior transport property for OFETs. Finally, we provide a summary concerning the methodology to improve the transport property of the pyrene-based semiconducting materials as well as an outlook.

The boundedness for commutators of maximal hypersingular integrals with rough kernels

In this paper,we prove that the commutators of maximal hypersingular integrals with rough kernels are bounded from the Sobolev space Lpγ(Rn) to the Lebesgue space Lp(Rn),which is a substantial improvement and an extension of some known results.

Dual-core photonic crystal fiber polarization splitter based on lead silicate glass

A dual-core photonic crystal fiber(PCF)polarization splitter based on lead silicate glass is proposed.The characteristics of the polarization splitter are analyzed using full-vector finite element method.Compared with the silica glass PCF polarization splitter with the same structure,it is shown that the new material polarizer can realize splitting with less coupling loss and higher extinction ratio.When the wavelength is 1 550 nm and the PCF length in the beam splitter is 688μm,the coupling loss is only 0.001 9 d B,and the extinction ratio for the input core is-64.1 d B.

The analysis of X-ray response of CdZnTe detectors

CdZnTe is an excellent material candidate for high efficiency,high-resolution room-temperature nuclear radiation detectors,and the CdZnTe detectors are being widely used in medicine,industry,safeguard and scientific X-ray and γ-ray imaging and spectroscopic applications.In this work,three CdZnTe planar detectors with different grades,named CZT-1,CZT-2 and CZT-3,respectively,were fabricated.And the effects of mobility,lifetime and de-trapping time on the performance of CdZnTe planar detector,such as the energy resolution,charge collection efficiency and peak to valley ratio,were analyzed.The charge collection efficiency depends on the product of carrier mobility and lifetime,which has a great effect on the energy resolution of detector when the efficiency is less than 90%.The de-trapping time of carriers in deep levels should be responsible for the peak to valley ratio and "polarization".

TWO-DIMENSIONAL FINITE ELEMENT MODEL OF TEMPERATURE DISTRIBUTION IN DERMAL TISSUES OF EXTENDED SPHERICAL ORGANS OF A HUMAN BODY

In the present study the thermal model of skin and subdermal tissues （SST） of human breast have been developed. The human breast is assumed to be spherical in shape with upper hemisphere projecting out from the trunk of the body and lower hemisphere is considered to be a part of the body core. The upper hemisphere represents the breast and its SST region is divided into three layers namely epidermis, dermis and subdermal tissues. The inner part of the breast represents the core/shell of the breast. The outer surface of the breast is assumed to be exposed to the environment from where the heat loss takes place by conduction, convection, radiation and evaporation. The heat transfer from core to the surface takes place by thermal conduction and blood perfusion. Also metabolic activity takes place at different rates in different SST layers of the breast. Boundary conditions have been framed on the basis of physical conditions. A finite element model has been developed for a two-dimensional steady state case.

Thermal distribution analysis of multi-core photonic crystal fiber laser

The thermal properties of photonic crystal fiber(PCF) laser with 18 circularly distributed cores are investigated by using full-vector finite element method(FEM).The results show that the 18-core PCF has a more effective thermal dispersion construction compared with the single core PCF and 19-core PCF.In addition,the temperature distribution of 18-core PCF laser with different thermal loads is simulated.The results show that the core temperature approaches the fiber drawing value of 1800 K approximately when the thermal load is above 80 W/m which corresponds to the pumping power of 600 W approximately,while the coating temperature approaches the damage value of about 550 K when the thermal load is above 15 W/m which corresponds to the pumping power of 110 W approximately.Therefore the fiber cooling is necessary to achieve power scaling.Compared with other different cooling systems,the copper cooling scheme is found to be an effective method to reduce the thermal effects.