Cardiac output determination by simple one-step rebreathing technique

We have developed a rebreathing technique for measuring cardiac output in resting or exercising subjects. The data needed are the subject's CO2 dissociation curve, the initial volume and CO2 fraction of the rebreathing bag, and a record of CO2 at the mouth during the maneuver. From these one can obtain all the values required to solve the Fick equation. The combined error due to inaccuracy in reading the tracings and to the simplifying assumptions was found to be small (mean = 0.5%, SD ;.5%). Cardiac output values determined with this technique in normal subjects were on the average 2% higher than those obtained simultaneously with an acetylene rebreathing method (n = 49, SD = 11%). Among the advantages of the technique are that it requires analysis of a single gas, takes less than thirty seconds per determination, allows one to obtain repeated measurements at rapid intervals, is not affected by the ability of lung tissue to store CO2, and eliminates many of the assumptions usually made in non-invasive measurements of cardiac output.     

A portable blood gas analyzer for equine venous blood

Evaluation of a portable blood gas analyzer, (StatPal II, Unifet, Inc, La Jolla, CA) was performed using tonometered solutions and equine blood. Samples were analyzed by the StatPal II and either an Instrument Laboratory IL1306 (Lexington, MA) or a Radiometer ABL50 blood gas analyzer (Radiometer America Inc., Westlake, OH). Comparison of the StatPal II and the IL1306 was done by analysis of 3 tonometered solutions (acidic, normal, and alkalotic) and 27 equine venous blood samples. Blood pH, PCO2, PO2, and [HCO3] values were altered by IV infusion of 5% sodium bicarbonate or exercising the horses on a treadmill. Comparison of the StatPal II and the Radiometer was performed by analysis of 78 blood samples collected from Standardbred horses before a race. Data were analyzed for the venous blood samples using a paired two-tailed Student's t test and Bland-Altman plots, with significance set at P < .05. The coefficients of variation for pH, Pco2, Po2, and [HCO3-] values of the tonometered solutions analyzed by the StatPal II ranged from 0.067% to 0.087%, 2% to 3.21%, 1.21% to 2.67%, and 0.267% to 0.828%, respectively. Comparison of the equine blood samples analyzed by the StatPal II and the IL1306 demonstrated statistically significant, but clinically irrelevant differences in pH, Pco2, and Po2, but not [HCO3-]. There were statistically significant, but clinically irrelevant differences between the StatPal II and the Radiometer for pH, Pco2, and [HCO3-], but not for Po2. It is concluded that the StatPal II provides reproducible and acceptable analysis of equine venous blood gas samples.     

A modified Harrington technique for scoliosis

Photoaffinity labeling is a powerful technique to identify ligand-binding proteins in a crude mixture and localize their binding-site. Benzophenone photophore has several favorable features compared with the classical photoreactive unit, aromatic azides, that is why its application is expanding. Benzophenone can easily be attached to biologically active ligands by using a tritiated heterobifunctional crosslinker reagent: [3H]-BZDC-NHS or a photoreactive amino acid; [3H]-4-benzoyl-L-phenylalanine. Tethered inositol polyphosphates and antimitotic agents were prepared first and reacted with the high specific activity photocrosslinker reagent in microscale. The photoactivatable ligands obtained were used for studying IP3 receptor, alpha-Trinozitol receptor, PLC delta enzime, beta-tubullin and glycoprotein P. Thrombin receptor was investigated by a short peptide antagonist containing the photoactivatable amino acid. The results demonstrate the versatility of photoaffinity labeling and prove that this technique has a potential providing much more information about the receptor and mechanism than simply identifying a single polypeptide: it contributed to solve the 3D structure of the IP3 binding domain and to reveal a unique activation of the PLC delta. The results confirmed the superiority of benzophenone. Using that photophore glycoprotein P, which is responsible for the MDR, and thrombin receptor were labelled at the first time.     

Alveolar gas relationships during the use of semi-closed rebreathing anaesthetic systems

A black box and a geometrical approach have been used to deduce the relationships between alveolar oxygen and carbon dioxide concentrations when rebreathing occurs during the use of semi-closed anaesthetic rebreathing systems.     

单光路激光气体分析仪在转炉煤气回收中的应用

针对转炉煤气回收柜前、干法除尘工艺中电除尘装置后煤气浓度分析的重要性和目前分析系统的不足,结合冶金行业大力推行节能减排、绿色炼钢的可持续发展模式,介绍济南钢铁股份有限公司第三炼钢厂新炼钢转炉的煤气浓度分析仪,详细说明激光分析仪工作原理,重点介绍单光路激光气体分析仪在转炉干法除尘中的应用问题。实践证明激光分析仪能够满足在转炉煤气回收利用中煤气浓度的监测功能要求。     

日本Horiba-EMIA-8200红外碳硫分析仪的修复

通过对EMIA-8200红外碳硫分析仪的分析、修复,找出其存在故障的几个方面.详细描述红外碳硫分析仪气路、光路以及高频振荡电路部分的故障处理过程.通过修复,对这类设备的原理、构造有了进一步的了解,在积累维修经验的同时增添了许多维修技巧,为今后的维修工作奠定了坚实的基础.     

A modified occlusal registration and implant transfer technique

The technique for the transfer of implant and abutment position to a working cast has been hindered by multiple transfers and record reproductions. These serve only to delay completion of the patient's prosthetic requirements. A transfer technique that uses custom impression trays fabricated from surgical templates allows for a single-visit transfer of centric occlusion, vertical dimension, tooth position, and implant or abutment location in one procedure. This streamlines treatment and allows for quicker delivery of final prostheses.     

A new type of oxygen analyzer utilizing a potentiostatic coulometric titration technique

A new type of oxygen analyzer was constructed utilizing the electrochemical oxygen pump: Pt, air/ZrO₂ (+ CaO)/Ar + H₂ + H₂0 gas mixture, Pt. Copper, indium, or tin samples were melted in a circulating Ar + H₂ gas mixture; the oxygen content was then determined within 3 minutes from the change in the electrical current passing through the oxygen pump. The analytical values were highly consistent and reliable despite the fairly low oxygen concentrations in the samples. Neither standard samples nor the establishment of blank conditions was necessary. This type of oxygen analyzer appears to be useful for determining oxygen concentrations less than 1 wt ppm.     

External radiotherapy for circumscribed choroidal haemangiomas using a modified retinoblastoma technique

This report describes two cases of circumscribed choroidal haemangiomas involving the fovea, complicated by serous retinal detachment. Laser photocoagulation, generally accepted as the treatment of choice for choroidal haemangioma, was considered either to be of no visual benefit or a risk for jeopardizing vision further due to the subfoveolar lesions. Fractionated radiotherapy using a lens-sparing, modified retinoblastoma technique, was given, using circular fields of 15 mm diameter. The dose was 24 Gy in 8 fractions. In both eyes the retina reattached completely. The visual acuity improved markedly in the first, and was restored to the prior level in the second. Normalization of a high intraocular pressure was also achieved in the second case. We believe this method to be a reasonable and effective therapy for some choroidal haemangiomas after careful individual consideration.     

Creation of a neovagina using ultrasonography-assisted laparoscopy (modified Vecchietti technique

Ultrasonography-assisted laparoscopic creation of a neavagina was performed on 6 patients suffering from vaginal aplasia. As the needle progress through the vesicorectal space, ultrasonography provided an accurate check of the bladder and rectal integrity, and improved the ease of the surgical procedure. Ultrasound can be considered an effective and reliable advance for laparoscopic management of vaginal aplasia.     

红外碳硫仪中绘图软件及其应用

介绍了LECO CS-444红外碳硫仪微机操作系统中绘图软件,分析了不正常碳(硫)释放曲线产生原因并制定了解决办法,举例说明碳(硫)含量平均值控制图、碳(硫)含量值控制图的使用方法.     

Desflurane and errors of gas selection on vaporizer analyzer

With monochromatic infrared gas spectrometers (MIS), the displayed concentration is computed from measured IR absorption and a gain factor specific for the selected volatile agent (VA). As MIS cannot detect which VA is actually present, the displayed concentration can be very different from the actual one. As bottles and vaporizers are very specific for desflurane, it is impossible to misfill a vaporizer; however an erroneous selection of VA on MIS remains possible. The aim of this study was to assess the displayed concentrations after erroneous vapour selection on the monitor. When either desflurane, or isoflurane or enflurane were delivered at constant concentrations, all VA measured by the MIS, namely desflurane, sevoflurane, isoflurane, enflurane and halothane were successively selected and the displayed concentrations compared with the actual vapour concentration using a Capnomac Ultima (Datex) monitor. Consequences of erroneous selection can be included in three categories: 1) dangerous error, when a displayed concentration is much lower than the actual one, e.g. desflurane or sevoflurane erroneously selected; 2) evident error, when displayed concentration is much higher than 10 vol%; 3) uncomfortable situation, when displayed and actual concentrations are similar, e.g. isoflurane erroneously selected instead of desflurane. This error can only be detected by a careful checking of the device.     

The urethral closure pressure profile. A new technique using gas and simultaneous EMG-recording from the urethra

A new technique for recording of the urethral closure pressure profile using gas-inflation and simultaneous EMG-recording from the urethra is described. With the present technique, the parameters of the urethral closure pressure profile in healthy volunteers were in accordance with previous reports using water-infusion. The effect of alpha-adrenergic blockade on the pressure profile was studied in a series of patients. Half of the patients showed a marked reduction of the intraurethral pressure in the presphincteric part of the profile after alpha-adrenergic blockade. This indicated that sympathetic innervated smooth musculature gives a significant contribution to the total intraurethral pressure.     

A modified repair technique for tricuspid incompetence in Ebstein's anomaly

OBJECTIVE: A modified technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. Midterm results of this therapeutic approach for patients with Ebstein's anomaly and tricuspid valve incompetence are reported. METHODS: Between October 1988 and April 1997, the incompetent tricuspid valve was repaired with our technique in 19 patients (12 female, 7 male; 2 to 54 years, mean 21 years). The indication for operation was congestive heart failure of various degrees in all patients. Tricuspid incompetence was grade II in two patients, grade III in 14, and grade IV in three. Associated congenital malformations were simultaneously repaired (interatrial communication in 18, ventricular septal defect in two, pulmonary stenosis in two, mitral valve prolapse in one). Follow-up ranged between 10 and 103 months (median 28 months) and was complete for all patients. RESULTS: There were no operative deaths. One patient with active endocarditis and pulmonary abscess died 2 months after the operation of recurrent sepsis; there were no late deaths. During follow-up, New York Heart Association functional class improved from 2.8 before the operation to 1.9 without recurrent cyanosis, and tricuspid incompetence decreased from a mean grade of 3.1 to one of 0.9, without any echocardiographic deterioration of the tricuspid valve function or right ventricular dilation. CONCLUSIONS: Our technique allows tricuspid valve repair in patients with Ebstein's anomaly, even in cases usually reserved for primary valve replacement, without late functional deterioration.     

烟气成分分析装置在提高炉窑热效率中的应用

介绍燃烧产物及烟道气体中氧气和一氧化碳的含量对炉窑热效率的影响,以及烟气分析仪器的工作原理及其在提高炉窑热效率中的应用。     

Thermodynamics of the Cr-Mn system using an isopiestic technique

Activities of manganese in solid chromium-manganese alloys have been determined at 1223, 1273, and 1323 K using an isopiestic technique. The activities of manganese show positive deviations from Raoult’s law over chromium-rich compositions. The positive deviation of the system is found to decrease progressively with increase in the manganese content of the alloys. The data have been interpreted based on calculation involving solid-liquid equilibria in the system.