ABSTRACT
Technical design and clinical assessment of skeletal traction kit is presented. The kit consists of 2 washers, 2 cylinders with blocking screws and a chain with hooks. The set is applied along with K-wire stretched in the buckle. The washers and blocking cylinders restrict longitudinal movements of the K-wire. Rotational ones are eliminated by resting the buckle (with no traction) on the extremity. The traction is executed by the chain attached to the K-wire near the buckle fastenings. Patients comfort and aseptic condition is improved. The modification proved valuable after observation of 38 patients treated by this method.
Subject(s)
Bone Diseases/surgery , Traction/instrumentation , Arm , Equipment Design , Humans , LegABSTRACT
An exact analysis of the excess noise in a two-mirror laser that takes into account the intracavity elements and the position of the active medium is presented. The influence of the active medium's position and length of the laser cavity on the excess noise factor is shown.
ABSTRACT
We present an approximate analysis of the nonlinear operation of the hollow-waveguide laser, including gain saturation and longitudinal- as well as transverse-field distribution of the laser mode. The model presented is general and can be applied to the study of an arbitrary configuration of the waveguide laser. The laser characteristics obtained reveal that the optimal position of the output mirror (which provides maximal power efficiency of the laser system with the other parameters constant) depends on the output-power level and the mirror-reflectivity coefficient. Moreover, it has been shown that when an addition device is introduced into the cavity, the power efficiency also depends on which end of the laser the light power is extracted from.
ABSTRACT
An analysis of the quantum noise in distributed-feedback lasers based on the Fokker-Planck equation has been developed to take into account the nonorthogonal nature of the laser modes. We have obtained numerical results of the steady-state solution of the single-mode operation that reveal the difference between the standard approach orthogonal laser modes and the realistic model (mode nonorthogonality included) for a distributed-feedback laser with nonvanishing end reflectivity and the complex coupling coefficient.
ABSTRACT
A simple analytical expression is derived relating the waveguide laser output power to the distributed loss, the mirror reflectances, the waveguide dimensions, and the small-signal gain coefficient. In our model the transverse-mode distributions are taken into account and the longitudinal field distribution is approximated by the threshold field distribution.
ABSTRACT
At concentrations up to 6.7 ppm, 8-methoxypsoralen, sphondin, and khellin are not toxic to first-instar larvae of the mosquitoAedes aegypti. The irradiation of sensitized larvae with long-wavelength ultraviolet light did not always produce any immediate toxicity enhancement, but delayed effects were clearly visible. These were observed over the development of the organisms from first-instar larvae to adults. No adverse effects were noted when larvae were irradiated in the absence of sensitizers, or when they were placed in solutions of sensitizers which had been previously irradiated with the same light sources. 8-Methoxypsoralen was slightly more phototoxic than its isomer sphondin. Khellin, recently reported to undergo photoinduced cyclization with DNA components, showed minimal phototoxicity in the concentration range used.
ABSTRACT
In vitro megakaryocyte differentiation is regulated by two activities: a megakaryocyte colony-stimulating activity (Mk-CSA), which is required for proliferation, and an auxiliary factor, megakaryocyte potentiating activity, which plays a role in later differentiation events. Tumor-promoting phorbol esters alter many cellular differentiation-related events. Thus, it was hypothesized that phorbol esters may bring about megakaryocyte differentiation in vitro. 4 beta-Phorbol 12-myristate 13-acetate (PMA), when co-cultured with a source of Mk-CSA, stimulated a threefold increase in colony numbers. Co-culture of PMA and megakaryocyte potentiator activity did not stimulate colony formation, thus eliminating any action of PMA as an Mk-CSA. The direct effect of PMA on the formation of megakaryocyte colonies was established by (a) the function of PMA as a megakaryocyte potentiator in serum-free experiments, (b) the ability of PMA to stimulate megakaryocyte colony formation using bone marrow cells depleted of populations known to produce potentiating activity, (c) the inability of bone marrow adherent cells previously treated with phorbol, 12,13-dibutyrate (PDBu) to augment megakaryocyte colony formation, and (d) the ability of PMA to induce the growth of immature megakaryocytes into large single megakaryocytes. Structure:activity experiments resulted in equivalent activities for PMA and PDBu, whereas the nontumor promoter phorbol 12,13-diacetate and phorbol itself lacked activity. The observations in this study indicate that phorbol esters can bring about megakaryocyte differentiation, and during colony formation, can induce effects identical to those brought about by biological sources of megakaryocyte potentiator activity.
