Spontaneous pulsation of the retinal veins

The classical theory of spontaneous pulsation of the retinal veins is that during systole intraocular pressure exceeds venous pressure, causing the veins to collapse. We show that this theory is internally inconsistent and not in accord with experimental data. It is inconsistent in assuming both (a) that oscillations of intraocular pressure (IOP) occur because the veins cannot immediately discharge the systolic arterial inflow and (b) that retinal venous pressure (RVP) can fluctuate independently of IOP during the cardiac cycle. It is not in accord with experimental data, which shows that RVP always exceeds IOP and that fluctuations in the latter are instantly transmitted to the former. We present an alternative theory that does not have these problems. We assume the following. (1) Inflow to the retinal venous tree from the capillaries is constant, the pulsatile arterial flow having been completely damped by the arterioles and capillaries. (2) Outflow from the central retinal vein (CRV) varies during the cardiac cycle because oscillations of IOP, transmitted to the intraocular CRV, are of greater amplitude than oscillations in cerebrospinal fluid pressure, transmitted to the extraocular CRV. By showing that the radial blood flow distending the veins obeys a diffusion equation and by employing an "equivalent cylinder" analysis of the branched venous tree to simplify the boundary conditions, we demonstrate that, with the above assumptions and the additional assumption of low amplitude of radial flow, the CRV will pulsate, and the pulsations will remain confined to a small segment near the exit point. The proposed theory can explain disappearance of pulsation with intracranial hypertension, intensification of pulsation in glaucoma, and variability in the linear extent and amplitude of pulsation among normal individuals. The theory may also be applied to other venous pulsations, such as the respiratory pulsation of the terminal portions of large veins entering the thorax or the cardiac cycle pulsation of the superior vena cava.     

自振射流喷嘴振荡腔内信号检测方法

为了获取喷嘴振荡腔内的压力脉动信号,提出一种新的检测方法.首先分析自振射流的特性,设计了产生自振射流的喷嘴结构;结合计算流体动力学分析喷嘴腔内动压分布,确定测压点位置;运用流体网络理论分析自振射流的频率特性,在此基础上确定用于实验的微型高响应压力传感器;考虑到腔内振荡信号的非平稳性,采用希尔伯特-黄变换（HHT）信号分析方法.实验结果表明,腔内振荡信号主要集中于40~60 Hz、110~150 Hz和200~310 Hz三个频带,且组成频率成分所对应的幅值差异明显;距离喷嘴出口较近处,自振信号振幅较大,频带窄.     

Short-term effects of initial, nonsurgical periodontal treatment (hygienic phase)

Longitudinal studies have reported the effect of various modalities of periodontal surgery on pocket depth and attachment levels related to pretreatment measurements. However, possible changes in these measurements as a result of scaling, oral hygiene improvements and occlusal adjustment during the hygienic phase were not considered. The purpose of the present study was to examine the short-term effect of treatment of the hygienic phase in 90 patients with some pockets extending 4 mm or more apically to the CEJ. Pretreatment pocket depths and attachment levels related to the CEJ were measured by a thin probe in five sites at all 2,355 teeth in the sample. Scaling, root planing, instruction in oral hygiene and occlusal adjustment were completed during four to six sessions for each patient. Four weeks after completion of the hygienic phase, all variables were recorded. Mean measurements for pocket depths 1-3 mm, 4-6 mm, and greater than or equal to 7 mm prior to treatment were compared to their posttreatment scores. Pocket depth decreased significantly for pockets extending 4 mm or more apically to the FGM. For pockets 4-6 mm there was a mean difference in pocket depth of 0.96 +/- 0.47 mm (P < .0001) between pretreatment and posttreatment observations. For pockets 7 mm or greater the mean difference was 2.22 +/- 1.35 mm (P < .0001). Reduction in depth of pocket and improvement in attachment levels were related to the initial level of severity. Pocket reduction was in part due to the improvement in attachment levels. This study has demonstrated that the clinical severity of periodontitis is reduced significantly 1 month following the hygienic phase of periodontal therapy, and that need for surgical pocket treatment cannot be assessed properly until completion of the hygienic phase of treatment.     

A method for motion compensation of a moving nematode Caenorhabditis elegans and its application to frequency analysis of pharyngeal pulsation

A new sequential image processing method for motion compensation of a moving object with stringy shape has been developed for estimating the pharyngeal pulsation of the nematode Caenorhabditis elegans under several environmental conditions. The method is based on the pixel data transfer on a new image frame while changing the boundary shape and the position but preserving the conformation of the inner structure of an object. All digitized image frames of C. elegans were first converted to motion-compensated images to arrange the pulsation site in the same region of the every transformed frame. The pulsation site was then automatically detected by determining the pixels where the temporal brightness variation was much larger than that of the other pixels. Finally, the pulsation frequency was determined by the Fourier analysis. The validity of our method has been confirmed by analyzing various test data, and the method has been applied for detecting the pharyngeal pulsation frequencies of C. elegans on some environmental conditions, i.e. feed bacteria-free/rich, doping of nerve inactivating ethyl-alcohol and nerve stimulant neurochemical substance of serotonin. The motion compensation method automatically provided reasonable pulsation frequencies which were found to be comparable to those obtained by manual counting. Thus the method is useful for systematic investigations on the variation of pharyngeal pulsation associated with the activity change of the nervous system in environments.     

含锑废水处理方法研究

随着国家对环境保护力度的加大,含锑废水的综合治理已成为锑行业的全新课题.本文探讨了铁盐水解沉淀净化含锑废水的方法,介绍了反应机理,工艺方法选择,试剂配比对净化效果的影响.     

Fenton氧化-混凝工艺处理焦化废水的研究

采用Fenton试剂氧化-混凝沉淀法深度处理焦化生化处理二沉池出水,考察了H2O2投加量、Fe2+/H2O2(物质的量比)、PFS(聚合硫酸铁)投加量、pH值、反应时间对TOC和COD去除效果的影响,确定了适宜的反应条件。试验结果表明,TOC和COD去除率最高分别达到90.7%和72.7%,出水COD浓度达到GB 8978—1996《国家污水综合排放标准》一级。     

The choice of the method for the surgical treatment of bladder exstrophy

129 children with exstrophy of the bladder underwent primary surgical reconstruction according to G. A. Bairov. Morphofunctional findings in these children gave grounds for determination of three degrees of the bladder congenital defects. 39 patients had defect of the 1st degree, 53 of the 2nd and 37 of the 3d degree. The results of plastic reconstruction of the bladder with local tissue support the validity of such procedure only for patients with the congenital defect degree I. For degree II the benefit is relative. In degree III plastic surgery in contraindicated.     

An endoscopic treatment method for postoperative stenoses

A 68-year-old-male was admitted to our hospital with the chief complaint of macrohematuria. He was diagnosed with malignant lymphoma at 63 years old. Cystoscopy and computerized tomography revealed a non-papillary and broad based tumor at the anterior wall of the urinary bladder and partial cystectomy was done. Pathological diagnosis was collision tumor between squamous cell carcinoma and malignant lymphoma. To our knowledge, this is the 13th case of collision tumor associated with genitourinary organs in the literature.     

A statistical technique for determining compliance with dual hygienic standards

A mathematical technique was developed to calculate log-normal distribution for sample results. This is then compared with a Limiting distribution defined by the sampling time, the Time-Weighted Average and the Ceiling Limit standard for the material tested. The technique provides a more effective means to decide if either or both the T.W.A. or Ceiling Limit has been exceeded. Sample times from 10 minutes to 4 hours are considered. A similar technique has previously been reported for evaluating benzene exposures. Examples are provided to illustrate the procedure.     

The hygienic requirements for the construction, operation and water quality of swimming pools

Data concerning operative treatment of 227 patients with lithiasis of the extrahepatic biliary ducts, covering an eleven-year period (1985 to 1995 inclusive), are presented. In all cases diagnosis and operation are done in the Second Surgical Clinic at the Medical University--State University Hospital "Alexandrovska"--Sofia. By type the surgical interventions are distributed as follows: external drainage of hepaticocholedochus--122 cases (53.74 per cent), choledochoduodenostomy 69 (30.39 per cent) and transduodenal papillosphincterotomy 36 (15.85 per cent). Fifteen patients develop postoperative complications (6.60 per cent), and in five patients the outcome is fatal with postoperative lethality amounting to 2.20 per cent. The basic indications for the various types of surgical interventions are established.     

Monte Carlo method to study the proton fluence for treatment planning

The proton beam at the Hahn Meitner Institute (HMI) in Berlin will be used for proton therapy of eye melanoma in the near future. As part of the pre-therapeutic studies, Monte Carlo calculations have been performed to investigate the primary fluence distribution of the proton beam including the influence of scattering foils, range shifters, modulator wheels, and collimators. Any material in the beam path will modify the therapeutic beam because of energy loss, multiple scattering, range straggling, and nuclear reactions. The primary fluence information is a pre-requisite for most pencil-beam treatment planning algorithms. The measured beam penumbra has been used as one of the parameters to characterize a proton beam for further calculations in a treatment planning algorithm. However, this phenomenological quantity represents only indirect information about the properties of the proton beam. In this work, an alternative parameterization of the beam exiting the vacuum window of the accelerator, as well as the beam right in front of the patient collimator, is introduced. A beam is fully characterized if one knows (for instance from Monte Carlo simulations) the particle distribution in energy, position, and angle, i.e., the phase space distribution. Therefore, parameters derived from this distribution can provide an alternative input in treatment planning algorithms. In addition, the method of calculation is introduced as a tool to investigate the influence of modifications in the beam delivery system on the behavior of the therapeutic proton beam.     

Minimally invasive method for treatment of supra-diacondylar femoral fractures

The "gold standard" treatment modality for extra-articular and combined intra-, extra-articular fracture of the distal femur is the condylar blade plate (CP). Large exposure of the distal femur with unavoidable iatrogenic trauma to the soft tissue surrounding the fracture site and perhaps the lack of stiffness of the eccentric lateral cortical location of the CP has been suggested to play a role in the high rate of infections and pseudarthrosis reported in the literature. In an effort to overcome some of the difficulties with the condylar blade plate and to reduce complications, an unreamed, titanium, solid nail, locked proximally with two locking screws and distally with a screw and twisted blade was developed (DFN). The nail was designed for minimal invasive reduction through a small median parapatellar arthrotomy of the articular fracture (percutaneous screw) and of the supracondylar fracture. The DFN is a modular system sharing many components and almost all instrumentation with the AO-UFN and it is expected that the nail is much better in axial stiffness and strength than the condylar blade plate. The treatment of supracondylar femoral fractures should be improved by providing early weight bearing and accelerated fracture healing with a reduced incidence of delayed unions and infections.     

A new method for the surgical treatment of patients with paralysis of the tongue

Skeletal muscle biopsies from 18 children and 8 from their mothers were studied in mitochondrial myopathies. It is shown that by means of electron microscopy, histochemistry, and morphometry the correct diagnosis of mitochondrial insufficiency is quite possible.