Intraoperative retinal light damage reflected in electrophysiologic data

In a series of 30 unilaterally pseudophakic patients, electroretinograms and electrooculograms were recorded 6 months postoperatively. The unoperated on fellow eyes served as controls High intraoperative retinal light exposure (3.4–7.3 mW/cm², Zeiss OPMI 6 operating microscope) caused a substantial reduction of electrophysiologic potentials. Light protection prevented deterioration of electroretinogram and electro-oculogram potentials; reducing the bulb voltage, tilting the axis of illumination, filtering short wavelengths and the use of light shields resulted in 4-log-unit lower intensities (0.8–3.7 W/cm²).Abbreviations ACL anterior chamber lens - ECCE extracapsular cataract extraction - ICCE intracapsular cataract extraction - PCL posterior chamber lens     

Effect of 3 mg melatonin on jet lag syndrome in an 8-h eastward flight

In order to assess the effect of melatonin on jet lag a field study was undertaken. The process of re-entrainment of circadian melatonin rhythm was investigated in six subjects. Except during 24-h blood sampling, the subjects were exposed to natural zeitgeber (time giver) outdoors and given 3 mg melatonin at 23:00 h. The subjects were exposed to bright sunlight from 3000 to 12000 lx. All of them showed orthodromic re-entrainment with taking melatonin, while two out of the six did not show orthodromic re-entrainment without taking melatonin. Melatonin accelerated the rate of the re-entrainment of the circadian melatonin rhythm. Melatonin was useful to jet travel from Tokyo to Los Angeles.     

2001年—2003年第1季度北京地区门诊患者降血糖用药动态分析

目的 :了解北京地区糖尿病患者的用药需求 ,并对降血糖药物进行分析。方法 :采用《医院处方分析》课题 (北京地区 )2 0 0 1年～ 2 0 0 3年每年第 1季度门诊降血糖用药的处方数据进行比较。结果与结论 :通过统计 ,北京地区糖尿病患者人数不断增多 ,且人们更多选用了新型降糖药。在临床应用中 ,口服制剂以磺酰脲类用量居主导地位 ,而α-葡萄糖苷酶抑制剂用量逐年上升 ;使用基因合成人胰岛素较动物胰岛素的用量逐年增多 ,为控制糖尿病用药及合理应用提供了依据     

Prosopo-Thoracopagus Conjoined Twins and Other Cephalopagus-Thoracopagus Intermediates: Case Report and Review of the Literature

Prosopo-thoracopagus twins are united from the face down to the umbilicus, none with union in the brain but all with visceral anomalies intermediate between those of cephalopagus and thoracopagus. In a review of over 1200 cases of conjoined twins reported during the past 100 years, there were 14 that illustrate the continuum between cephalopagus and thoracopagus, including three that were united only from the cervical region to the umbilicus. Classic cephalopagus twins are joined from the top of the head to the umbilicus, sharing a single foregut as well as two relatively normal hearts, the “posterior” one often diminished. Typical thoracopagus, however, are conjoined only from the upper thorax to the umbilicus, each twin with a normal foregut but both sharing a single complex multiventricular heart. The intermediate cases shared either a single very abnormal heart or two hearts united by double aortic arches, and all except one had a single foregut. It is these cases intermediate between cephalopagus and thoracopagus which are the subject of this report. Received September 11, 1996; accepted December 16, 1996     

Carcinoma of the cervix: Value of dynamic magnetic resonance imaging in assessing early stromal invasion

Background The purpose of this study was to assess the accuracy of contrast-enhanced magnetic resonance imaging (dynamic MR imaging) in the evaluation of preinvasive and early invasive cancer of the cervix. Methods Twenty-nine women with untreated squamous cell carcinoma of the cervix with either no stromal invasion or early stromal invasion underwent pretreatment MR imaging and dynamic MR imaging within 4 weeks of surgical evaluation. The images were evaluated for tumor detection and compared with results of histologic examination of the surgical specimens. Results The lesions in 17 cases with histologically proven stromal invasion of 4 mm or greater were detected with dynamic MR imaging, whereas lesions in only 8 of these cases were detected with T2 imaging. In 9 cases with stromal invasion between 4.0 mm and 5.0 mm, lesions were represented as early phase focal enhancement on dynamic MR images, but not detected on T2-weighted images. In the 12 cases with less than 4 mm stromal invasion, no lesions were visualized on either T2-weighted images or dynamic MR images, except in 1 case of glandular involvement without stromal invasion that appeared as enhancement on early-phase dynamic MR imaging. Conclusion Dynamic MR imaging detected more lesions of early stromal invasion in pretreatment imaging for cervical cancer than nonenhanced MR imaging.     

CT图像中噪声产生机理与维修

本文重点阐述和分析了CT图像中的几种噪声产生的原因和对图像的影响,并结合笔者多年的维修经验,从理论和实际相结合,介绍了几种实用的维修方法,提出了减小噪声提高图像质量的有效措施。     

早期原发性开角型青光眼的视网膜光阈值改变

目的:观察早期原发性开角型青光眼视网膜光敏度分布情况及改变特点。方法:采用日本TopconSBP2020自动视野SDT340程序检测早期原发性开角型青光眼与正常眼的中心3°视网膜光敏感度。结果:早期原发性开角型青光眼各方向的视网膜光敏度与正常眼比较有非常显著差异(P<0.01);早期原发性开角型青光眼上方视网膜光敏度与其他各方比较有显著差异(P<0.05);早期青光眼的MD,ST与正常眼比较差异非常显著(P<0.01)。结论:视网膜光敏度的定量检测能做为早期原发性开角型青光眼的较早期视功能检测。     

Liquid Guayule Natural Rubber,a Sustainable Processing Aid,Enhances the Processability,Durability and Dynamic Mechanical Properties of Rubber Composites

Petroleum-based oils are widely used as processing aids in rubber composites to improve processability but can adversely affect rubber composite performance and increase carbon footprint. In this research, liquid guayule natural rubber (LGNR), produced from guayule natural rubber, was used as a renewable processing aid to replace naphthenic oil (NO) in Hevea natural rubber, styrene-butadiene rubber (SBR) and guayule natural rubber (GNR) composites. The rheological properties, thermal stability, glass transition temperature, dynamic mechanical properties, aging, and ozone resistance of rubber composites with and without NO or LGNR were compared. Natural and synthetic rubber composites made with LGNR had similar processability to those made with NO, but had improved thermal stability, mechanical properties after aging, and ozone resistance. This was due to the strong LGNR–filler interaction and additional crosslinks formed between LGNR and the rubber matrices. The glass transition temperature of SBR composites was reduced by LGNR because of its increased molecular mobility. Thus, unlike NO, LGNR processing aid can simultaneously improve rubber composite durability, dynamic performance and renewability. The commercialization of LGNR has the potential to open a new sustainable processing-aid market.     

A Numerical Measurement Method for Dynamic Granular Materials Based on Computer Vision

Granular materials are widespread in nature and human production, and their macro-mechanical behavior is significantly affected by granule movement. The development of computer vision has brought some new ideas for measuring the numerical information (including the amount of translation, the rotation angle, velocity, acceleration, etc.) of dynamic granular materials. In this paper, we propose a numerical measurement method for dynamic granular materials based on computer vision. Firstly, an improved video instance segmentation (VIS) network is introduced to perform end-to-end multi-task learning, and its temporal feature fusion module and tracking head with long-sequence external memory can improve the problems of poor video data quality and high similarity in appearance of granular materials, respectively. Secondly, the numerical information can be extracted through a series of post-processing steps. Finally, the effectiveness of the measurement method is verified by comparing the numerical measurement results with the real values. The experimental results indicate that our improved VIS obtains an average precision (AP) of 76.6, the relative errors and standard deviations are maintained at a low level, and this method can effectively be used to measure the numerical information of dynamic granular materials. This study provides an intelligent proposal for the task of measuring numerical information of dynamic granular materials, which is of great significance for studying the spatial distribution, motion mode and macro-mechanical behavior of granular materials.     

Cone signals for spectacle-lens compensation: differential responses to short and long wavelengths

Chick eyes compensate for defocus imposed by spectacle lenses by making compensatory changes in eye length and choroidal thickness, a laboratory model of emmetropization. To investigate the roles of longitudinal chromatic aberration and of chromatic mechanisms in emmetropization, we examined the participation of different cone classes, and we compared the efficacy of lens compensation under monochromatic illumination with that under white light of the same illuminance to the chick eye.Chicks wore positive or negative 6 D or 8 D lenses on one eye for 3 days, under either blue (460 nm) or red (620 nm) light at 0.67 lux or under white light at 0.67 or 0.2 lux (all measures are corrected for chick photopic sensitivity). The illumination conditions were chosen to differentially stimulate either the short-wavelength and ultraviolet cones or the long-wavelength and double cones. Measurements are expressed as the relative change: the inter-ocular difference in the amount of change over the 3 days of lens wear.We find that under this low illumination the two components of lens compensation were differentially affected by the monochromatic illumination: in blue light lens compensation was mainly due to changes in eye length, whereas in red light lens compensation was mainly due to changes in choroidal thickness. In general, white light produced better lens compensation than monochromatic illumination.

Negative lenses

Under white light negative lenses caused an increase in eye length (60 μm) together with a decrease in choroidal thickness (−51 μm) relative to the fellow eye. Under blue light, although there was an increase in eye length (32 μm), there was no change in choroidal thickness (5 μm). In contrast, under red light there was a decrease in choroidal thickness (−62 μm) but no increase in eye length (8 μm). Relative ocular elongation was the same in white and monochromatic light.

Positive lenses

Under white light positive lenses caused a decrease in eye length (−142 μm) together with an increase in choroidal thickness (68 μm) relative to the fellow eye. Under blue light, there was a decrease in eye length (−64 μm), but no change in choroidal thickness (2 μm). In contrast, under red light there was an increase (90 μm) in choroidal thickness but less of a decrease (−36 μm) in eye length. Lens compensation by inhibition of ocular elongation was less effective under monochromatic illumination than under white light (white v red: p = 0.003; white v blue p = .014).The differential effects of red and blue light on the choroidal and ocular length compensatory responses suggest that they are driven by different proportions of the cone-types, implying that, although chromatic contrast is not essential for lens compensation and presumably for emmetropization as well, the retinal substrates exist for utilizing chromatic contrast in these compensatory responses. The generally better lens compensation in white than monochromatic illumination suggests that longitudinal chromatic aberration may be used in lens compensation.