A circular tunnel kiln for firing of refractories

Conclusions The first high-temperature circular tunnel kiln in the country, in which firing of mullite-corundum refractories with a phosphate binder at 1400–1500°C has been introduced, has been placed in service.The operation of the kiln is characterized by the high service reliability of its design elements, including the hearth system, and insignificant costs for routine repairs of the kiln equipment.Translated from Ogneupory, No. 2, pp. 40–44, February, 1985.     

Modeling of nucleation of orthosilicic acid in geothermal brine

On the basis of a mathematical model, a program is developed for numerical modeling of orthosilicic acid nucleation in geothermal brine with the formation of colloidal silica particles. Data on the dependence of the process parameters on the properties of brine (temperature, pH, and total silica concentration) are obtained. These data can be used to design technological systems of silica removal from the geothermal heat-transfer medium.     

Expression of a hypoglycosylated form of CD86 (B7-2) on human T cells with altered binding properties to CD28 and CTLA-4

CD80 (B7-1) and CD86 (B7-2) on APC provide a major costimulatory signal through interactions with CD28 on T cells. Absent from resting human T cells, CD86 is up-regulated early upon T cell activation, whereas CD80 expression appears later. Whereas T cell expression of CD80 has been implicated in costimulation, the functional significance of CD86 expression on T cells is unclear. We now demonstrate that CD86 expressed on human CD4+ T cell clones does not provide a costimulatory signal for other CD4+ T cell clones. Binding studies using CD28-Ig and CTLA-4-Ig fusion proteins demonstrate that CD86 expressed on T cells has significantly reduced binding affinity for CTLA-4 and no detectable binding to CD28. Biochemical analysis demonstrates that post-translational modifications of CD86 in human T cells are different from those of CD86-transfected Chinese hamster ovary cells or EBV-transformed B cells, in that T cells express a hypoglycosylated form of CD86 on the surface membrane. Thus, our results suggest that while CD86 is expressed on a number of different cell types, its costimulatory function and affinity for its ligands may be regulated by cell type-specific post-translational modifications.     

Use of X-Ray Thickness Gauges in Manufacturing Rolled Non-Ferrous Metals

A technique of taking into account modifications of the chemical composition of alloys in measuring the thickness of rolled non-ferrous metal products by X-ray thickness gauges is described. The possibilities and perspectives of using RIT10 X-ray thickness gauges in rolling mills with a wide assortment of treated non-ferrous metals and their alloys are demonstrated. The accuracy reached in measurements of tested objects of different thicknesses and chemical compositions is estimated and factors affecting the accuracy of device readings are indicated.     

Anterior ridge preservation and augmentation using a synthetic osseous replacement graft

A 7-year retrospective study, reporting 3 cases, is presented in which particulate synthetic osseous replacement grafts were placed for ridge preservation and augmentation in the maxillary anterior region after extraction of periodontally hopeless teeth. The ability of an osseous replacement graft to prevent and correct the postextraction atrophy of the alveolar ridge, as well as its esthetic implications in fixed prosthetics, is discussed.     

Oxidative damage to the eye lens caused by cigarette smoke and fuel smoke condensates

The degree to which a reformed U.S. health care system relies on an adequate supply of primary care physicians will determine the urgency of change in the composition of the medical workforce. In many areas of the United States, the demand for primary care physicians, particularly in managed care settings, far exceeds the supply. In contrast, reports of reduced practice opportunities for medical and surgical subspecialists in the same settings are increasing. As opportunities for and incomes of primary care physicians are enhanced, some medical subspecialists may seek retraining in primary care. This article provides a context for understanding the development of physician retraining programs, examines precedents for retraining physicians, describes four possible pathways through which medical subspecialists might acquire primary care training, and emphasizes the importance of defining the scope of practice and necessary skills for providing primary care. Obstacles to retraining appear to be economic (Who will pay? Is the cost worth the benefit?) and jurisdictional (Who will define core competencies? Who will credential programs and trainees?). The current absence of demand for such retraining programs suggests either that marketplace-induced changes will not take place or that the notion of a primary care provider shortage and an oversupply of medical subspecialists is overstated. The inclusion of physician retraining programs in proposed health reform legislation suggests that policymakers are convinced that such programs offer one viable solution to the nation's medical workforce needs.     

Disulfide bond mapping and structural characterization of spruce budworm antifreeze protein

We have previously reported that bryostation 1 (Bryo 1) induces differentiation of chronic lymphocytic leukemia (CLL) in vitro to a hairy cell (HC) stage. This study tests the hypothesis that Bryo 1-differentiated CLL cells are more susceptible to 2-chlorodeoxyadenosine (2-CdA) than parent CLL cells. A recently established EBV-negative CLL line (WSU-CLL) from a patient resistant to chemotherapy including fludarabine was used to test this hypothesis. Both Bryo 1 (10-1000 nM) and 2-CdA (5.6-22.4 microM) exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. In vitro, the sequential exposure to Bryo 1 (100 nM for 72 h) followed by 2-CdA (11.2 microM) resulted in significantly higher rates of growth inhibition than either agent alone. Changes in immunophenotype, enzymes, lipids, proteins, and the DNA of WSU-CLL cells were studied before and after Bryo 1 treatment. Bryo 1 induced a positive tartrate-resistant acid phosphatase reaction and two important markers, CD11c and CD25, after 72 h of culture, confirming the differentiation of CLL to HC. The Fourier transformation infrared spectroscopic analysis showed that the amount of membrane lipids significantly increased in Bryo 1-treated cells compared to controls after 24 h, whereas the protein content, as well as the DNA content, decreased. This finding supports the change of CLL to HC. To evaluate the in vivo efficacy of Bryo 1 and 2-CdA, we used a xenograft model of CLL in WSU-CLL-bearing mice with severe combined immune deficiency. s.c. tumors were developed by injection of 10(7) WSU-CLL cells, and fragments were then transplanted into a new batch of severe combined immunodeficient mice. Bryo 1 and 2-CdA at the maximum tolerated doses (75 micrograms/kg i.p. and 30 mg/kg s.c., respectively) were administered to the mice at different combinations and schedules. The survival in days, the tumor growth inhibition ratio, the tumor growth delay, and the log10 kill of the mice treated with Bryo 1 followed by 2-CdA were significantly better than the control and other groups. We conclude that the sequential treatment with Bryo 1 followed by 2-CdA resulted in higher antitumor activity and improved animal survival.