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PubMed2003

Development of a computer model using the EGS4 simulation code to calculate scattered X-rays through some materials.

In this paper a computer model based on the use of the well-known Monte Carlo simulation code EGS4 was developed to simulate the scattering of polyenergetic X-ray beams through some materials. These materials are: lucite, polyethylene, polypropylene and aluminium. In particular, the ratio of the scattered to total X-ray fluence (scatter fraction) has been calculated for X-ray beams in the energy region 30-120 keV. In addition scatter fractions have been determined experimentally using a polyenergetic superficial X-ray unit. Comparison of the measured and the calculated results has been performed. The Monte Carlo calculations have also been carried out for water, bakelite and bone to examine the dependence of scatter fraction on the density of the scatterer. Good agreement (estimated statistical error < 5%) was obtained between the measured and the calculated values of the scatter fractions for materials with Z < 20 that were studied in this paper.

Absorptiometry, Photon↗

PubMed1998

Experience with three-port laparoscopic cholecystectomy.

After considerable experience with laparoscopic cholecystectomy (LC) using four ports, we began using three-port LC in October 1993 and have performed 130 LCs with this procedure up to May 1996. The procedure was successful in 119 patients. In 6 patients fourth port was used, and in another 5, the procedure was converted to open laparo-tomy. Cooperative manipulation of the surgical instruments between the operator and assistant is very important for this procedure, for exposing Calot's triangle and dissecting the gallbladder from the gallbladder bed. The use of an ultrasonic aspiration system (Sumisonic ME 2400; Sumitomo Bakelite, Tokyo, Japan) made it easier to identify the cystic duct and artery, especially in patients with chronic inflammation or dense adhesions. We encountered no problems with cannulation into the cystic duct for intraoperative cholangiography, and there were no intra- and postoperative complications in this series. We achieved good results, similar to those achieved with the four-port technique. This technique is technically feasible and safe, and it has esthetic and cost advantages compared with the four-port technique. However, the operator who performs three-port LC should not hesitate to add another port, or to convert to open laparotomy, whenever any difficulties occur during this procedure, to prevent critical complications.

Cholecystectomy, Laparoscopic↗

PubMed1989

Solid phase enzyme-linked immunosorbent assay (ELISA) for anti-sheep erythrocyte antibody in mouse serum.

The solid phase enzyme-linked immunosorbent assay (ELISA) was developed to measure IgM and IgG anti-SRBC antibody titers in mouse serum. Sheep erythrocytes, which have a surface negative charge, were attached directly to the bottom of an aminoplate well (96-well flat bottom, Sumitomo Bakelite Co.) which is charged positively to provide a solid phase for the ELISA antigen. Serum samples titrated were obtained from mice 5 and 10 days after SRBC immunization. Alkaline phosphatase-labeled goat anti-mouse IgM and/or IgG preparations were used as second antibody. Alkaline phosphatase activity in a well was measured by the Kind and King method [Kind, P. R. N. & King, E. J. (1954). J. clin. Path., 7, 322-326]; the optical density (OD) value of quinone as a final product was measured at 492 nm. (1) A linear relationship was observed between the antiserum concentration and OD value over a wide enough dilution range to assay antibody titers of serum samples; (2) IgM and IgG fractions from antiserum showed almost the same antibody titer as did the reconstituted samples; (3) a good correlation was observed between the serum IgM titer and the number of IgM hemolytic plaque-forming cells (PFCs) in spleen 5 days after the immunization, and was also observed between serum IgG antibody titer and the number of IgG PFCs 5 and 10 days after. Therefore, the ELISA described here requires no fixative for preparation of cell-coated plates, and serum IgM and IgG anti-SRBC antibody titers can be measured without any fractionation technique.

Alkaline Phosphatase↗

PubMed2004

A simple cryogenic holder for tensile testing of soft biological tissues.

To overcome the difficulty of gripping soft biological materials for tensile test, a simple inexpensive cryogenic holder was developed which allows rapid (3 min) preparation of samples. It is made of 6 parts, built in a bakelite cloth, which is an excellent thermal isolant, and is used with rectangular (8x10(-2)x10(-2)x10(-2)m) samples. The holder with the sample inside is completely immersed in liquid nitrogen for 50 s. This duration allows the freezing of the sample ends on a 10(-2)m length and gives a very flat freezing surface throughout the sample cross section. The 6x10(-2)m central part of the sample remained at ambient temperature. Two parts of the holder help maintain the sample until its ends are vertically gripped in the tensile machine thus avoiding any sample deformation during this step. No pressure was applied on the frozen part of the sample by grips of the tensile machine and this avoids breaks in this region. The sample is fixed by adhesion forces (>1 kN) between its frozen parts and 2 pieces of the holder. The procedure has been successfully tested with bovine and salmon muscle samples and results show tensile breaks randomly distributed in the unfrozen region of the samples. Particular attention has been paid to obtain a very flat freezing surface so that the axial strain is equal throughout the sample and therefore any strain-related mechanical parameters can be accurately determined. The dimensions of the holder can be easily modified to fit other sample geometries and can be used with other biological materials.

Animals↗

PubMed1978

Transapical aortic perfusion with a double-barreled cannula.

The transapical aortic perfusion method is a new approach to cardipulmonary bypass and is performed with an infusion cannula placed in the ascending aorta through the left ventricular apex. The technique is applicable to almost all varieties of open-heart surgery, and is the most efficient method in infants and small children. A double-barreled forked cannula performs the two functions of aortic infusion and left ventricular decompression. With a Bakelite obturator, its cannulation to the aorta is very quick and easy. The transapical aortic perfusion method with a double-barreled cannula has been utilized in 156 open-heart operations with 17 perioperative fatalities and 1 late death. The 138 surviving patients have done well for periods up to four years. The perfusion method was developed from the left heart bypass and assisted circulation technique independently invented by Chardack's group and by us in 1966 and 1969, respectively.

Adolescent↗

PubMed2001

Fingermarks detection by eosin-blue dye.

Eosin-blue (I) dye, along with a phase transfer catalyst, has been used to detect latent fingerprints on a wide range of surfaces, including paper, glass, steel, lamination sheets, polythene, plastic and bakelite.

Dermatoglyphics↗

PubMed2001

Automatic mass-rearing of Amblyseius womersleyi (Acari: Phytoseiidae).

Using incorporated devices, Tetranychus urticae spider mites were rinsed from hydroponically-grown lima bean plants, collected, separated and blow-dried. This yielded a reliable and large volume of eggs and larvae, which were fed to Amblyseius womersleyi rearings on 15 x 5 cm2 polyethylene arenas. Of several feeding regimes tested, daily feeding of 10 mg T. urticae eggs and larvae resulted in the highest predator population levels. The best harvest period was between 15 and 27 days, when predator density exceeded 600 mites per arena. A preliminary automatic mass-rearing device was tested for A. womerslyi. This incorporated both rearing and harvesting procedures. A micro-feeder was developed to supply the required volume of spider mites and maize pollen (1:1 mixture) to the predators. A Bakelite rearing arena reduced the space requirements of a polyethylene arena, was more durable and an essential component in the automatic mass-rearing and harvesting. Mite harvesting is carried out through the use of a vacuum-head harvester. Supplements of (sterilized) spider mites, pollen, vermiculite and wheat bran are automatically added to the predators. The devices for harvesting, filling and packing are incorporated and synchronized and the entire system is controlled by a single slide-switch. The design and system can be expanded without changing the basic processes and program, for example to adopt it for other species of predaceous mites.

Animal Husbandry↗

PubMed2002

Direct calibration of a reference standard against the air kerma strength primary standard, at 192Ir HDR energy.

The primary standard of low air kerma rate sources or beams, maintained at the Radiological Standards Laboratory (RSL) of the Bhabha Atomic Research Centre (BARC), is a 60 cm3 spherical graphite ionization chamber. A 192Ir HDR source was standardized at the hospital site in units of air kerma strength (AKS) using this primary standard. A 400 cm3 bakelite chamber, functioning as a reference standard at the RSL for a long period, at low air kerma rates (compared to external beam dose rates), was calibrated against the primary standard. It was seen that the primary standard and the reference standard, both being of low Z, showed roughly the same scatter response and yielded the same calibration factor for the 400 cm3 reference chamber, with or without room scatter. However, any likelihood of change in the reference chamber calibration factor would necessitate the re-transport of the primary standard to the hospital site for re-calibration. Frequent transport of the primary standard can affect the long-term stability of the primary standard, due to its movement or other extraneous causes. The calibration of the reference standard against the primary standard at the RSL, for an industrial type 192Ir source maintained at the laboratory, showed excellent agreement with the hospital calibration, making it possible to check the reference chamber calibration at RSL itself. Further calibration procedures have been developed to offer traceable calibration of the hospital well ionization chambers.

Air↗

PubMedDate not supplied

On the selection of stopping-power and mass energy-absorption coefficient ratios for high-energy x-ray dosimetry.

A method for the selection of average stopping-power (L/rho)medair and energy-absorption coefficient (mu en/rho)medair ratios has been developed. The quality of the x-ray beam is characterized by the ratio of ionization chamber readings at depths of 20 and 10 cm in water (TMR)2010. For convenience, a relationship is established between experimental (TMR)2010 and the nominal accelerating potential (MV) of the accelerator. Experimental (TMR)2010 are related to (L/rho)medair and (mu en/rho)medair in a three-step process. First, using experimental and theoretical spectra in the range 60Co to 45 MV, (TMR)2010 were calculated for primary and first-scatter photons, and a graph of experimental versus calculated (TMR)2010 for these same spectra was constructed. Second, (L/rho)medair and (mu en/rho)medair were calculated for a large number of primary spectra [for most of which experimental (TMR)2010 were not available] and a graph constructed that related these quantities and (TMR)2010 calculated as above for this group of spectra. Third, using the graphs from the preceding steps, graphs relating the calculated (L/rho)medair and (mu en/rho)medair with experimental (TMR)2010 were constructed. Data are presented for water, polystyrene, acrylic, graphite, A-150, C-552, Bakelite, and nylon for beams with nominal accelerating potentials in the range 2-45 MV.

Humans↗

PubMed1984

Electric oral burns in Danish children with special reference to prevention.

68 children, most of them 1-3 years old, with electric burns of the mouth from slight cases to severe burns with extensive necroses were treated over a 30-year period. Principles of primary conservative treatment and secondary reconstructive surgery are mentioned. A Stein- Abbe flap procedure, single or double, has been the method-of-choice in severe defect of the lower lip. In the majority of the cases the accident was caused by a defective bakelite plug from the detachable cord of a popular electric vacuum cleaner of Danish origin. In 1968 a plea was made for a change of this kind of plug to a better type made of an unbreakable plastic material. As a prophylactic measure this intervention seems to have been very useful in so far as the number of these senseless accidents has decreased dramatically in Denmark during the last 15 years.

Accidents, Home↗

PubMedDate not supplied

[The first total hip prostheses in man (1890 - 1960)].

We owe the first total prosthesis to Th. Gluck from Berlin (1880-1890), (they were in ivory), and to Jules Pean from Paris (1890-1894) (they were in platinum and cemented with plaster and pumice). Hardly successful though they were, the idea of replacing an articulation by foreign material was born. It would take sixty years to come to a successful hip total prosthesis. In the 1930 ies, Smith-Petersen, from Boston, designed moulds to be set between the femoral head and a cotyle in glass, pyrex, Bakelite and eventually a metal cupule (vitallium) either set on to the cotyle or the femoral head. After 1940 Bohlmann and Moore were the first to replace the upper part of a femur bearing a tumour and a metal prosthesis. In 1947, Jean and Robert Judet proposed a femoral head in acrylic. The first successful femoral prosthesis (more than 50 % good results) was Moore's new metal prosthesis in 1950. In the 50ies, some surgeons had the idea of connecting the two prosthetic pieces (cupule and femoral prosthesis) to get a total prosthesis, mainly in metal (Mc Kee from Norwich in 1951 and Herbert from Aix les Bains around 1955). In 1960, Charnley used dentist's methalcrylate cement for a Moore femoral prosthesis. In 1962, Charnley used this cement for a total prosthesis, with the low-friction concept and a 22 millimeter femoral head, which could move in a polyethylene cupule. This prosthesis is still in use today, in 1999.

Hip Prosthesis↗

PubMed1987

[Protective effect on the brain of ion-blockers in experimental head injury].

It has been known that various derangements in ionic homeostasis develop following neural trauma. In particular, potassium efflux out of and calcium influx into the cells are thought to play important roles in causing cell damage. Concomitantly we have previously reported that increased extracellular potassium per se provoked by head injury induces convulsive seizure such that the sustained high extracellular potassium leads to animal death. The purpose of the present study was further to examine the beneficial effect of drugs which could inhibit such detrimental ion movements in experimental head injury. Awake male mice of dd-strain were restrained and subjected to head injury using a bakelite weight of 30 gm dropped from a height of 17.6 cm above the skull. This injury resulted in immediate loss of consciousness in 100%, convulsive seizure in about 70% and death in about 30% of animals. The severity of consciousness disturbance was evaluated by a pair of indices in time interval; time required for the recovery of righting reflex (RR) and for the recovery of spontaneous movement (SM). Ethacrynic acid, a loop diuretics, blocks carrier-mediated chloride transport into astroglia associated with sodium and water in the presence of high extracellular potassium. Animals were treated with either 0.5-1.0 mg/kg or 2.0-4.0 mg/kg of ethacrynic acid administered via tail vein 10 min before injury. In the other group of animals, a calcium entry blocker, flunarizine was injected intraperitoneally in doses 5, 10 and 20 mg/kg one hour pre-insult.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

[The influences of neurotransmitters on the traumatic unconsciousness, immediate convulsion and mortality in the experimental mice model].

In order to clearing the influence of neurotransmitters in concussive unconsciousness, immediate convulsion and mortality, the following experiments were performed. Awake male mice of dd-strain were restrained and subjected to head injury using a bakelite weight of 30 gm dropped from a height of 20 cm on to the skull. This injury resulted in immediate loss of consciousness in 100%, convulsive seizure in 66% and death in 30% of animals. The severity of consciousness disturbance was evaluated by two parameters; (1) time interval required for the recovery of righting reflex (RR) and (2) time interval for the recovery of spontaneous movement (SM). Agonist or antagonist of various neurotransmitters was given intraperitoneally 0.5 or 2 hours before injury. The following results were obtained although some of them were statistically not significant. Physostigmine shortened both RR (p less than 0.1) and SM (p less than 0.01), whereas scopolamine did not change these intervals. Atropine sulfate shortened both of them. Nevertheless, atropine methylbromide, which dose not pass through blood-brain-barrier, also had same effects. Methamphetamine shortened both RR (p less than 0.1) and SM (p less than 0.05), whereas haloperidol prolonged these intervals. 5-HTP shortened RR (p less than 0.05), but prolonged SM (p less than 0.1). Methysergide shortened both RR (p less than 0.05) and SM (p less than 0.01). Convulsive seizure was suppressed by physostigmine (p less than 0.01) or 5-HTP (p less than 0.20). These results suggested that suppression of dopaminergic and cholinergic systems, and/or activation of serotonergic system contribute to concussive unconsciousness.

Animals↗

PubMed1987

[Time course of the cerebroprotective effect of dexamethasone in experimental head injury].

Despite the widespread use of glucocorticoids in patients with severe head injury, the usefulness is still controversial. In the past, the effect was investigated only in terms of dose-response relationship. We have, however, studied the time factor for the administration of dexamethasone to obtain maximal beneficial effect together with investigating the influence of actinomycin-D, an inhibitor of messenger RNA synthesis, before dexamethasone treatment. Awake male mice of dd-strain were restrained and subjected to head injury using a bakelite weight of 30 g dropped from a height of 17.8 cm above the skull. This injury resulted in immediate loss of consciousness in 100%, convulsive seizure in about 70% and death in about 30% of animals. The severity of consciousness disturbance was evaluated by a pair of indices in time interval: time required for the recovery of righting reflex (RR) and for the recovery of spontaneous movement (SM). 4 mg/kg of dexamethasone phosphate was given intraperitoneally 0.5, 4, 6, 12, 18 or 24 hours before injury. Actinomycin-D of 0.5 mg/kg was injected intravenously 1 h before each dexamethasone treatment in separate animals. In the other group of animals, dose was changed with varying time course of dexamethasone pretreatment, e.g., 2, 4, 6 or 8 mg/kg given 0.5, 2 or 4 h before injury. It was found that dexamethasone of 4 mg/kg pretreatment 4-12 hours significantly improved the recovery from consciousness disturbance and death rate. Actinomycin-D given before dexamethasone treatment completely abolished the protective effect of dexamethasone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Evaluation of carcinogenic risk in friction product workers.

Mortality rates of two cohorts of asbestos friction product (FP) workers were studied in comparison with the population of the adjoining towns over periods of 20 and 40 years respectively. The second cohort was subdivided into 3 subcohorts exposed to chrysotile asbestos (CA), vulcanization and/or polymerization vapours and gases (VPGV) and asbestos bakelite (AB) or asbestos rubber (AR) dusts. In the first cohort no deaths from lung cancer were recorded, even though the total tumour mortality was higher than in the general population. In the second cohort an excess tumour mortality was observed in the first subcohort for stomach cancer only. In the other two subcohorts the expected rates were higher for all the tumour sites. Following intraperitoneal injection of CA, AB and AR dusts, malignant tumours developed in 31.5% of the rats which received CA, and in about 10% of the rats which were injected with AB and AR dusts. Also, the mean longevity of CA-treated animals was significantly lower than in the other two groups. Thus, the carcinogenic risk was real in the group of FP production workers with significant CA exposure only.

Adult↗

PubMed1976

[Mutual relations between plastic materials and bacteria (author's transl)].

The complex problems of microbiological degradation of synthetic plastics and a fairly wide variety of 62 testing materials, belonging to 14 major groups of plastics, are described. Adaequate and reliable testing techniques had to be devised. Drawing on the experiences of H. Braun, 1930, and of Bushnell and Haas, 1941, as to the metabolism of bacteria and the utilization of certain hydrocarbons by microorganisms, and previous research work by A. Schwartz in Berlin, 1959-60, on microbial corrosion of plastics, methods of laboratory testing were developed. The bacteriological technique was based on selection of aerobic microorganisms, which were, by starvation, adapted to use the plastic materials as their only carbon source; foreign carbon sources had to be strictly eliminated; emphasis was laid on proper, double control cultures. The test organisms involved included P. aeruginosa and fluorescens strains, also a certain species of Candida, and mixtures of soil, sewage and garbage organisms grown on exposed plastic surfaces. By means of series of passages the selective adaptation and conservation of these organisms was continued up to 4 1/2 years. An anaerobic adaptation method for Desulfovibrio desulfuricans was developed and used successfully. After preliminary experimentation (Soil burial, sewage and garbage exposure tests) in the laboratory as well as in the open, a large scale Field testing programme under realistic and to some extent extreme conditions was implemented: Nine different plastic materials comprising eight plain high polymer plastics and for comparison one synthetic Cellulose derivate, together with glass control samples, were exposed in twelve different sewage, garbage, and soil media over a period of 3 months to 2 years, and subsequently examined. On the basis of the bacteriological results obtained from the adaptation series the test materials were classified into three categories, corresponding to the stimulation of bacterial growth: Group one, which allowed strong proliferation, included certain types of plasticized P.V.C. and Cellulose esters, as expected, and, as a new result, Polyurethane rubber; the latter showed clear signs of surface corrosion. Group two, which induced a clear but moderate growth, comprised a nylon trade type of Polyamide. Gruop three, allowing weak but still recognisable growth, included Formaldehyde pressure resing (Bakelite). This was surprising as it was thought that the formaldehyde and phenol components would exert a bacteriocidic or at least bacteriostatic effect. The results of the long and time consuming adaptation series with Pseudomonas aeruginosa were confirmed by the manometric dissimilation method of O. Warburg by means of the Braun/Melsungen apparatus. With this subtle but elegant procedure results and graphical recordings were obtained within hours and days...

Candida↗