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At least 163 records · Page 9Linked to original sources
PubMed1989

Ultrasonic cleaning in the hospital.

Ultrasonic cleaning can prolong the life of expensive instruments. In the past, many fine instruments were discarded due to stiffening hinges and box locks, or sticking plungers. Hand scrubbing and spray washing could not thoroughly clean these areas. Ultrasonic cleaners effectively remove dried and baked blood, serums and medications from these instruments. Also, hinged instruments and syringes operate more smoothly during use in surgery when cleaned using ultrasonics. In addition, the use of ultrasonics alleviates the necessity for hand scrubbing of contaminated surgical instruments and laboratory apparatus, a procedure which could lead to injury or infection. The superb cleaning powers of ultrasonic cleaners, their speed and simplicity of operation, and their ability to remove blood, tissue, bacteria and microorganisms within minutes, makes them a valuable addition to any operating room suite, central service department, or emergency room. Their cost-effectiveness is considerable for the small hospital, and compelling for the large hospital.

Central Supply, Hospital↗
PubMed2003

Centrifugal partition chromatography: a survey of its history, and our recent advances in the field.

Centrifugal partition chromatography (CPC) was introduced in 1982 by Sanki Eng. And for almost 20 years this company remained the only one manufacturing such an apparatus. A CPC instrument or a CPC column is a series of channels linked in cascade by ducts and aligned in cartridges or disks in a circle around a rotor; setting the rotor in motion submits this assembly to a constant centrifugal field. The originality of CPC is that it uses any biphasic liquid-liquid system as mobile and stationary phases. The United States branch of Sanki contributed greatly to the worldwide acceptance of the technique. Recent works performed in the Netherlands and in France have, by means of visualization of flow-patterns in CPC channels, contributed to a better knowledge of hydrodynamics and mass transfer phenomena. Nowadays research in our laboratory focuses on speediness and scale-up of the technique.

Centrifugation↗
PubMed2006

Measurements of interfacial viscoelasticity with a quartz crystal microbalance: influence of acoustic scattering from a small crystal-sample contact.

We discuss the influence of a limited contact size on measurements of high-frequency interfacial viscoelasticity performed with a combination of a quartz crystal microbalance (QCM) and the Johnson-Kendall-Roberts (JKR) apparatus. In this instrument, a sphere-plate contact is established between an elastomeric lens and a quartz resonator. The analysis is carried out in the frame of the sheet-contact model, which states that both the shift of resonance frequency and the bandwidth are proportional to the contact area as long as the contact area is much smaller than the crystal itself. In particular, the ratio of the shift in bandwidth and the shift in frequency (termed the D-f ratio) is predicted to be constant and independent of geometry. However, the experiment does show a slight increase in the D-f ratio with the contact radius when the contact radius is comparable to the wavelength of sound inside the crystal. This effect can be explained by acoustic scattering.

Journal Article↗
PubMed1996

Deformation kinetics analysis of polymeric matrices.

PURPOSE: We hypothesize that if the kinetics and the mechanisms involved in tablet compression are more fully understood and quantified, the parameters which influence tablet behavior in production may be controlled. The objective of our work was to obtain two deformation kinetic parameters for the predominant barrier to deformation, the activation volume (Vact) and the activation energy (Eact) of poly (methyl methacrylate-co-methacrylic acid) (PMMA/coMAA), a viscoelastic polymer similar to the commercial Eudragit. METHODS: Stress relaxation studies were performed and monitored at varying temperatures on compacts using an instrumented Instron testing apparatus. Solid density, microindentation hardness and contact area testing served to quantify the shear stress rates. RESULTS: The Vact was found to be 64.4 +/- 4 b(3), 63.8 +/- 11 b(3) and 79.1 +/- 8 b(3) for the applied strain rates of 1, 2, and 5 mm/min. The Eact for flow was determined to be 145 +/- 7.7, 235 +/- 8.0, and 506 +/- 2.8 x 10(1) kJ/mole(-1) for the applied strain rates of 1, 2, and 5 mm/min respectively. CONCLUSIONS: The average activation energies are indicative of strain hardening effects. The activation volumes and energies obtained will serve as estimates of these state variables for input into a particle deformation model of time-dependent compaction which is underway.

Drug Carriers↗
PubMed1999

Tarsal autografts for reconstruction of the scapholunate interosseous ligament: a biomechanical study.

A biomechanical cadaver study was performed to identify a potential bone-ligament-bone autograft from the foot for reconstruction of the scapholunate interosseous ligament (SLIL). In this study the biomechanical properties of 9 dorsal tarsal ligaments and the anterior tibiofibular ligament were investigated and compared with those of the dorsal part of the SLIL. Fifteen fresh-frozen human cadaver feet and 14 fresh-frozen human cadaver wrists were used. In a Monsanto Tensometer testing apparatus (Monsanto Limited Instruments, Dorean Swindon, England) the complexes were uniaxially elongated at a constant velocity of 6.35 mm/min until rupture occurred. The stiffness and strength values for each tarsal ligament were calculated and compared with those of the dorsal part of the SL ligament. Analysis indicated that the third dorsal tarsometatarsal ligament (143 +/- 42 N) and the dorsal calcaneocuboid ligament (149 +/- 41 N) were comparable to the dorsal part of the SL ligament (141 +/- 20 N) while all other ligaments were stronger. The stiffness values of the third dorsal tarsometatarsal ligament (67 +/- 17 N/mm) and the dorsal calcaneocuboid ligament (55 +/- 14 N/mm) were comparable to the dorsal part of the SL ligament (61 +/- 6 N/mm). All the other ligaments had values that were higher than the dorsal part of the SL ligament. The strongest ligament appeared to be the medial dorsal cuneonavicular ligament (479 +/- 65 N), which had a stiffness value of 127 +/- 19 N/mm. Although the third dorsal tarsometatarsal ligament and the dorsal calcaneocuboid ligament are biomechanically most similar to the dorsal part of the SLIL, at present it is unclear how strength and stiffness values of ligaments are sustained following transplantation. From this selection of tarsal ligaments, the medial dorsal cuneonavicular ligament is the strongest ligament and it is therefore concluded that this ligament is the most suitable ligament to be used as an autograft for reconstruction of the SLIL.

Biomechanical Phenomena↗
PubMed1999

Compaction properties of powders: the relationship between compression cycle hysteresis areas and maximally applied punch pressures.

The consolidation behaviors of various pharmaceutical solids were characterized by investigating the relationship between the calculated hysteresis areas and the maximally applied punch pressures. An Instron universal testing apparatus and an instrumented die were used to generate compression cycle profiles at various maximally applied punch pressures for the materials studied. Based on the profiles obtained, hysteresis areas were calculated for the materials studied as a function of maximally applied punch pressures. Furthermore, model profiles describing the plastic and brittle fracture processes were utilized to derive mathematical relationships between the calculated hysteresis cycle areas and the maximally applied punch pressures. The mathematical relationships derived indicate that a linear relationship between hysteresis areas and maximally applied punch pressures exists for plastic materials, whereas for brittle materials the hysteresis areas are related to the square of the maximally applied punch pressures. Experimental data obtained support the mathematical relationships derived. The goodness of fit to the models derived is used to rank order the consolidation mechanism of various drugs and pharmaceutical excipients.

Chemistry, Pharmaceutical↗
PubMed2000

Noninvasive glucose determination by oscillating thermal gradient spectrometry.

BACKGROUND: Several noninvasive measurement approaches for the determination of blood glucose levels have been pursued over the past two decades. There is worldwide recognition that an unobtrusive and noninvasive measurement technique will better enable the patient with diabetes to obtain information for appropriate disease management. Many challenges have so far prevented any noninvasive technology from meeting the requirements. METHOD: In this article, we describe a novel optical technology that when applied to the human body, provides both the sensitivity and the specificity required for acceptance. For human tissue, specific wavelength bands in the mid- infrared (IR) region offer predominantly single component absorbances and thus, provide the basis for the required specificity of an in vivo determination of glucose. It is highly desirable to utilize these bands for the development of a practical spectroscopic technique. The use of mid-IR absorbance bands requires a methodology that accommodates relatively short optical transmission pathlengths. Thermal gradient spectroscopy is one suitable methodology. We describe the utilization of optical phenomena, which arise during a thermal gradient, in the development of a practical instrument. The prototype apparatus is described and results obtained from aqueous samples and tissue phantom studies are presented. Furthermore, a mathematical derivation is presented in the Appendix, that defines the relationship between the optical signals produced and the properties of the tissue under analysis.

Blood Glucose↗
PubMedDate not supplied

Observations on the current and future surgical management of hydatid disease affecting the vertebrae.

Five cases of hydatid disease affecting the vertebrae are described. Clinical features, radiologic appearance, and poor prognosis are emphasized. Four patients had some degree of neurologic deficit at the time of presentation and in three cases there was an increasing kyphosis. In two patients, spinal instrumentation with Harrington apparatus supplemented removal of hydatid material, and its use improved the previous neurologic deficit with stabilization of kyphosis. The antihelmintic drug mebendazole was used in two cases.

Adult↗
PubMed1989

The Cyclops 33 radiation thermometer. An appraisal for use in anaesthesia.

The Cyclops 33 is a portable infrared radiation thermometer. It has many potential advantages over existing thermometers in anaesthetic practice. The technical details are described and the benefits over other instruments discussed. This apparatus offers considerable scope for advance in the field of thermometry in anaesthesia.

Anesthesiology↗
PubMed1967

Instrumental assay of microbial lipase at constant pH.

A rapid, accurate method with high sensitivity and reproducibility, and having the advantage of a short incubation period under constant pH, has been developed for routine measurement of microbial lipase. Assembled from readily available and economical instrumental components, the apparatus includes a pH meter, a thermoelectric heating and stirring device, a motor-driven burette, and an automatic recorder. The reaction mixture, consisting of 5 ml of a 10% olive oil-gum arabic emulsion, 2 ml of 3 m NaCl, 2 ml of sodium taurocholate (15 mg/ml) of 0.075 m CaCl(2), 5 ml of water, and 1 ml of enzyme solution, was adjusted to pH 8.0 and 37 C. The pH was maintained at a constant value by automatic addition of 0.01 n NaOH during the incubation period, which usually lasted 5 min. A lipase unit, derived from the use of this technique, may be defined as the number of microequivalents of acid liberated per minute under the specified conditions. The method was sensitive to 0.01 units. Various organisms tested produced 0.17 to 1.32 units per ml of the cell filtrate. An Arrhenius plot for staphylococcal lipase yielded 14,500 cal for function A (energy of activation).

Alcaligenes↗
PubMed2000

Impacts of laboratory methodology on medical thinking in the 19th century.

During the 19th century the first laboratories at hospitals and clinics in Central Europe were established. These 'clinical laboratories' were devoted to chemical analyses in practical medicine and clinical research. A characteristic feature of these laboratories was the use of measuring instruments, e.g. volumetric apparatus, polarimeters, spectroscopes, colorimeters, photometers. Using these techniques new phenomena were introduced into clinical medicine which could serve as signs in the diagnosis of diseases. Many of the new diagnostic signs were quantitative data as results of measurements. Their main advantage was the greater differentiation in the description of phenomena compared with the qualitative data used before. Another important characteristic of the new diagnostic signs was the discovery of causal relations to physiological and pathological processes in the organism. The physicians and chemists in the clinical laboratory were eager not only to collect empirical data but also to find causal relationships by research work similar to that carried out in physics and chemistry. Once causal chains were been identified more general relationships became clear. One example is the concept of metabolism which comprised a dynamic view on chemical processes in the body and the variation of "Stoff" (material) in time, including a quantitative input-output analysis of the body in health and disease. In the second half of the 19th century, scientifically based diagnostic signs began to replace the traditional symptoms and signs used since antiquity.

Clinical Laboratory Techniques↗
PubMed1990

[Indications for and results of surgical scoliosis therapy using VDS instrumentation (ventral derotation spondylodesis)].

The complications of 97 patients who were operated with anterior spinal instrumentation were frequent, but insignificant. 22 of these patients with lumbar and thoracolumbar curves in whom the VDS instrumentation was used were reviewed. A 79% correction was obtained in the coronal plane. Loss of correction was 11% in the first year and further 2% at 56 months average follow up. In the sagittal plane a mild tendency to increased kyphosis was found. A permanent "adding on" phenomenon occurred in one case. The VDS-instrumentation appears the apparatus of choice for treatment of thoracolumbar and lumbar scoliosis, other indications are discussed.

Adolescent↗
PubMed1987

Treatment of the anterior cruciate ligament-absent knee with associated meniscal tears. Instrumented testing and clinical evaluation of two patient groups.

The UCLA instrumented clinical testing apparatus was used to measure postoperative stiffness and laxity for two groups of patients with documented chronic absence of the anterior cruciate ligament (ACL) and associated meniscal tears. Group 1 consisted of 76 patients (average age, 25 years) who had undergone anterior cruciate substitution using the torn meniscus, and a second group of 34 patients (average age, 31 years) who had partial meniscectomy alone without ACL substitution. Subjective and objective evaluations were significantly higher and symptoms of pain and buckling significantly lower in the substitution group. In addition, 29% of Group 1 and only 7% of Group 2 patients were able to return to their preinjury sports without limitations, while 5% of the former and 12% of the latter could not return to any sport. At 90 degrees of flexion, there were no significant differences in stiffness or laxity between the patient groups. At 20 degrees of flexion and neutral foot rotation, the meniscal substitution group had an average of 1.4 mm less side-to-side laxity difference than the partial meniscectomy patients; 51% of the substituted patients still had an injured knee laxity that was at least 2 mm greater than the uninjured knee, as contrasted to 67% of the partial meniscectomy patients who exceeded this upper limit of the normal range. At 20 degrees, anterior stiffness of the injured knees of the substitution patients was 28% greater than the injured knees of the partial meniscectomy group; 42% of the substituted patients had an injured knee stiffness within the normal range, while only 18% of the partial meniscectomy patients fell within normal limits. There were no statistical correlations of stiffness or laxity values with clinical scores or patient symptomatology in either group.

Adult↗
PubMedDate not supplied

[Computerized control with radiodiagnostic equipment in bronchopulmonary investigations].

The authors propose a procedure and equipment for control by using a rotation table of a PYM-20M X-ray system with an image intensifier. A 4 x 4-cm beam field is used. The procedure makes it possible to lower X-ray loads in patients by 10-15 times, to calculate the absorbed integrated radiation dose, to enhance the quality of plane films, to draw up a protocol of studies. This increases the accuracy of X-ray anatomic instrument position. The apparatus can be remotely controlled.

Adult↗