Improved integrating-sphere throughput with a lens and nonimaging concentrator

A reflectometer design utilizing an integrating sphere with a lens and nonimaging concentrator is described. Compared with previous designs where a collimator was used to restrict the detector field of view, the concentrator-lens combination significantly increases the throughput of the reflectometer. A procedure for designing lens-concentrators is given along with the results of parametric studies. The measured angular response of a lens-concentrator system is compared with ray-trace predictions and with the response of an ideal system.     

The effects of boundary conditions on the basal glide of ice crystals in compression

Creep experiments were conducted on ice crystals in compression to investigate the effects of boundary conditions on a single-slip system deformed in plane strain. Friction at the platens of the deformation apparatus introduces a bending moment which causes a variation in the amount of lattice rotation across the specimen. This is shown to occur in mechanically constrained crystals observed through plane polarized light. Relieving the constraints and minimizing friction at the ice-platen contact leads to the widening of the sample near the specimen-platen interface and the production of tails symmetrically disposed about the longitudinal axis of the deformed crystals. This is interpreted to originate from a bending moment in the opposite sense from that obtained in the constrained crystals, resulting from a progressive increase in slip displacement towards the platens where the segments of the slip plane become shorter. When the crystal ends were constrained but allowed to move sideways, a simple shear regime was established in which lattice slip was concentrated in the centre of the crystal.     

Angiogenesis of gynecologic tumors studied with color Doppler

Angiogenesis is obligatory event in solid tumors growth. Weak muscular layer in the newly formed tumoral vessels results in decreased resistance to blood flow and characteristic Doppler signal. The number and arrangement of the blood vessels differ between benign and malignant lesions as well. Parameters mentioned above enable a precise ultrasound differential diagnosis between benign and malignant tumors. Malignant uterine tumors are better perfused and have lower resistance to blood flow than benign ones. Benign lesions with secondary changes (necrosis) may have lowered resistance indices. The finding of pathological perfusion makes the diagnosis of endometrial carcinoma also very accurate. High sensitivity of the transvaginal color Doppler in detecting newly formed blood vessels in an early stages of ovarian cancer may establish this technique as a screening method for this still very high lethality disease.     

Prevention of thromboembolic disease in gynecologic surgery

We presented two groups of patients gynecologically operated and examined in a five year period; the first group of 11536 patients was under thromboembolic protection, whereas the second group of 8532 patients was without thromboembolic protection. Protective measures concerning thromboembolic disease were carried out by applying elastic stockings 24 hours before operation and by early post-operative getting up from bed. Low-molecular dextran was applied before operation as well as during the operation in the amount of 500-1000 ml. In risky patients with varicosities, recidive thrombophlebitis and cardiovascular diseases, we applied small doses of heparin subcutaneously two hours before the operation and after the operation every eight hours five days long. With such prevention of thromboembolic disease in gynecologic surgery, we achieved very favorable effects in reducing mortality to 0.05% concerning the operated, while it amounts to 0.3% in those who were without this kind of protection.     

Comfort of personal protective equipment

The degree of comfort of personal protective equipment (PPE) was investigated in an automobile encapsulating plant. Up to 96.2% of employees used one or a combination of PPE. Only 8% of the workers felt their respirators were comfortable, 30% tolerated their respirators, and 62% rated them as uncomfortable. The percentage of employees who rated their PPE (other than a respirator) as comfortable ranged from 32 to 52%. For comfort factor, coveralls/aprons rated 52%, safety glasses 51%, rubber gloves 42%, and hearing protectors 36%. PPE was tolerable (just acceptable) for about 30% of the employees. To increase the effectiveness and safety of PPE, the human-factor aspects of PPE design should be emphasized more and quality improvement should cover the wearability of PPE.     

Streptokinase contains two independent plasminogen-binding sites

Streptokinase (SK) exerts its thrombolytic effect by activating plasminogen (PG) indirectly, after the formation of an equimolar complex with either PG or plasmin (PN). The location and nature of the PG/PN-binding sites in SK have been explored using limited proteolysis with immobilized trypsin. Employing Western blotting with radiolabeled PG after SDS-PAGE of total tryptic digest, three fragments of MW 7 kD, 19 kD and 31 kD were found to possess PG-binding ability. Each of these fragments was then isolated by reverse phase HPLC and characterised with respect to its sequence, as well as its PG-binding properties by ELISA. These analyses revealed that in addition to a PG-binding site in the region 143-293 reported recently in the literature, there is another distinct, high-affinity and independent PG-binding site, located in the N-terminal region (residues 1-59) of SK. Using a synthetic peptide, the N-terminally located PG-binding-site has been further localised to the region 37-51 of SK. Further, we demonstrate that the PG-binding of this peptide is not mediated through the lysine-binding sites ("Kringles") of PG. This stretch contains a short sequence (LTSRPA) that is also present in the PG-binding domain of human fibronectin.     

Quantum concept of the rearrangement of a crystal lattice

Using quantum considerations based on the concept of lattice rearrangement waves, we carried out an analysis of processes of rearrangement of a crystal lattice occurring on a moving front (interface) of crystal rearrangement. For the introduction and quantization of these waves we use the method of acoustomechanical analogy and the Sommerfeld quantum conditions. We calculate the energies and the propagation velocities of the lattice rearrangement waves. Along with quanta having a certain momentum, quanta that have a certain angular momentum are introduced into consideration. On the basis of the concepts developed, we suggest a new expression for calculating the probability of thermofluctuational processes in a crystal. We perform a numerical analysis of the rate of growth of the -phase in iron in the process of --conversion. Satisfactory agreement with experiment is obtained. We discuss the limitations and prospects of further development of the concept suggested. For direct experimental verification of the concept we propose to investigate the diffraction of electrons and other particles on the lattice rearrangement waves, i.e., in the process of phase conversions or disintergration of crystals.Branch of the P. N. Lebedev Physical Institute of the Russian Academy of Sciences, Samara. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 1, pp. 136–142, January–February, 1995.     

Fabrication process for FEP piezoelectrets based on photolithographically structured thermoforming templates

Microsystem Technologies - Piezoelectrets fabricated from fluoroethylenepropylene (FEP)-foils have shown drastic increase of their piezoelectric properties during the last decade. This led to the...