Influence of Hydrogen Plasma on the Surface Structure of Beryllium

This paper presents the research results of hydrogen plasma effect on the surface structure of the TGP-56 beryllium. In the linear simulator, the operating conditions of the first wall of ITER are simulated. Beryllium was irradiated with hydrogen plasma at surface temperatures of ~360 °C, ~800 °C, and ~1200 °C, depending on its location in the ITER chamber; with a different number of pulses with a duration of each pulse of 500 s. Samples of irradiated beryllium were subjected to a set of material studies. Experimental data were obtained on the change in the structure of the surface and edges of the beryllium samples after the plasma effect. It was found that at normal (2 MW/m²) and increased (4.7 MW/m²) heat fluxes on the first wall of the ITER, the edges and beryllium surface have good resistance to erosion. Under critical conditions close to the melting point, beryllium strongly erodes and evaporates. It has been established that this material has a high resource resistance to hydrogen plasma effect in the ITER under operating conditions.     

Influence of the Carbidized Tungsten Surface on the Processes of Interaction with Helium Plasma

This paper presents the results of experimental studies of the interaction of helium plasma with a near-surface tungsten carbide layer. The experiments were implemented at the plasma-beam installation. The helium plasma loading conditions were close to those expected in the ITER divertor. The technology of the plasma irradiation was applied in a stationary type linear accelerator. The impact of the helium plasma was realized in the course of the experiment with the temperatures of ~905 °C and ~1750 °C, which were calculated by simulating heat loading on a tungsten monoblock of the ITER divertor under the plasma irradiation at the load of 10 MW/m² and 20 MW/m², respectively. The structure was investigated with scanning microscopy, transmitting electron microscopy and X-ray analysis. The data were obtained showing that the surface morphology changed due to the erosion. It was found that the carbidization extremely impacted the plasma–tungsten interaction, as the plasma–tungsten interaction with the carbide layer led to the carbon sputtering and partial diffusion towards to the depth of the sample. According to these results, WC-based tungsten carbide is less protected against fracture by helium than W and W₂C. An increase in temperature leads to much more extensive surface damage accompanied by the formation of molten and recrystallized flanges.     

The effect of 2 different bleaching regimens on the surface roughness and hardness of tooth-colored restorative materials.

OBJECTIVE: The purpose of this in vitro study was to evaluate the effects of 10% carbamide peroxide (Vivastyle/Vivadent) and 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) on the surface roughness and hardness of the 3 different tooth-colored restoratives: an ormocer (Definite), a packable composite (Filtek P60), and a flowable composite (Filtek Flow). METHOD AND MATERIALS: A total of 48 specimens (10 mm in diameter and 2 mm thick) of each material were fabricated against a mylar surface. After being polished with Sof-Lex discs, they were randomly divided into 3 groups of 16 and treated as follows: group I was stored in distilled water at 37 degrees C for 2 weeks (control), group II was treated with Vivastyle for 2 hours per day for 2 weeks, and group III was treated with Whitestrips for 30 minutes twice a day for 2 weeks. For groups II and III, the specimens were stored in distilled water at 37 degrees C during the hiatus period. At the end of the test period, the specimens were first subjected to surface roughness and then to microhardness tests. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Both bleaching regimens increased the surface roughness of the materials (P <.05), but Whitestrips significantly increased the roughness of materials more than did Vivastyle (P <.05). Both bleaching regimens decreased significantly the hardness of tested materials except Filtek P60 (P <.05). CONCLUSION: Bleaching agents may affect the surface of existing restorations; therefore, they should not be used indiscriminately when tooth-colored restorations are present.     

The ability of statins to inhibit bone resorption is directly related to their inhibitory effect on HMG-CoA reductase activity.

Statins, which are inhibitors of 3-hydroxy-3-glutaryl-coenzyme A (HMG-CoA) reductase, decrease the hepatic biosynthesis of cholesterol by blocking the mevalonate pathway. Nitrogen-containing bisphosphonate drugs also inhibit the mevalonate pathway, preventing the production of the isoprenoids, which consequently results in the inhibition of osteoclast formation and osteoclast function. Therefore, we hypothesized that statins could affect bone metabolism in vivo through effects on osteoclastic bone resorption. In vitro, cerivastatin inhibited the parathyroid hormone (PTH)-stimulated bone resorption. Using a panel of 40 statin analogs, which showed variable effects on HMG-CoA reductase activity, we found that the ability of compounds to inhibit bone resorption is directly related to HMG-CoA reductase activity. However, in the thyro-parathyrodectomy (TPTX) model for bone resorption in the rat in vivo, cerivastatin did not prevent experimentally induced increases in bone resorption. The lack of effect of cerivastatin in this model is not related to a limited penetration of the target tissue (bone marrow), because a significant effect on HMG-CoA reductase activity was demonstrated in the total rat bone marrow cell extracts of rats posttreatment in vivo. Furthermore, cerivastatin inhibited protein prenylation in osteoclasts isolated from the rabbit bone marrow of rabbits after treatment in vivo. In contrast to other studies, none of the statins tested showed anabolic effects in parietal bone explant cultures. Taken together, we conclude that statins inhibit bone resorption in vitro, which correlates directly with the potency of the compounds for inhibition of HMG-CoA reductase activity. However, cerivastatin does not affect bone resorption in the rat TPTX model in vivo.     

Osteochondroma of the mandible causing severe facial asymmetry: a case report.

Osteochondroma is one of the most common benign tumors of bone. Although osteochondroma is rarely seen in facial region, the cases in literature are usually in the mandibular region, especially around the condyle. The treatments of these lesions include total condylectomy or local resection of the lesion. The aim of the present study is to emphasize the importance of stereolithographic models in planning tumor surgery and how it affects the treatment planning, operation time and prognosis. In this report, the patient had an osteochondroma in the left condylar region, pushing the condyle seriously to the anterior. The clinical findings were 8 mm deviation of midline to the right side, 23 mm mouth opening, unilateral posterior cross-bite on the right side, and 8 mm negative horizontal overjet. We acquired a 3-dimensional solid model of the patient. Determination of the anatomy of the surgical area, determination of the surgical access method, and other treatment planning were all done on the stereolithographic model. Based on the model evaluation, the tumor was conservatively resected and the condyle left intact, leaving no sequelae. All the preoperative problems were resolved except the midline deviation.     

Array comparative genomic hybridization profiling of first-trimester spontaneous abortions that fail to grow in vitro

OBJECTIVES: Cytogenetic analysis of spontaneous abortion samples can be limited by culture failure. Failure to grow in vitro has traditionally been suspected to be due to in vivo death of tissue associated with spontaneous abortion (SAB) or simply technical factors of growth in culture. METHOD: We used array comparative genomic hybridization (array CGH) to investigate chromosomal imbalances in products of conception that failed to grow in vitro. RESULTS: Our data on 26 cases of SABs that failed to grow in culture are compared and contrasted with published data on cytogenetic findings following in vitro culture. The results revealed abnormalities uncommonly seen by classic cytogenetic methods. These abnormalities include high rates of double aneuploidy and autosomal monosomy. The data taken together suggest that classic cytogenetics of spontaneous abortion may yield normal karyotypes or selected abnormal karyotypes that permit cell proliferation in vitro while Array CGH detects other abnormalities. CONCLUSION: Array CGH is becoming an important clinical assay for unbalanced chromosome abnormalities whether cells grow in culture or not and in cases of analysis on one or few cells.     

Virus-cell fusion as a trigger of innate immunity dependent on the adaptor STING

The innate immune system senses infection by detecting either evolutionarily conserved molecules essential for the survival of microbes or the abnormal location of molecules. Here we demonstrate the existence of a previously unknown innate detection mechanism induced by fusion between viral envelopes and target cells. Virus-cell fusion specifically stimulated a type I interferon response with expression of interferon-stimulated genes, in vivo recruitment of leukocytes and potentiation of signaling via Toll-like receptor 7 (TLR7) and TLR9. The fusion-dependent response was dependent on the stimulator of interferon genes STING but was independent of DNA, RNA and viral capsid. We suggest that membrane fusion is sensed as a danger signal with potential implications for defense against enveloped viruses and various conditions of giant-cell formation.     

Multiple systemic infarctions as a complication of bronchial artery embolization with polyvinyl alcohol: a case report

Bronchial artery embolization (BAE) is a widely used modality of treatment for massive hemoptysis which has well known complications such as chest pain, groin hematoma and transverse myelitis but systemic embolization of the material used in the procedure is very rare and was reported only four times in the literature which were all caused by the use of microspheres. Herein we report a case of a 41-year-old caucasian male who had a history of tuberculosis 10 years ago. He had BAE with polyvinyl alcohol (PVA) for the treatment of recurrent hemoptysis. After the procedure, the patient complained of severe pain on the left upper quadrant and bilateral costovertebral regions and in abdominal CT, multiple infarcts in the subcapsular area of the spleen and kidneys were observed. This is the first reported case of inadvertent systemic embolization secondary to BAE with PVA. Although the risk of systemic embolization is greater with microspheres, still potentially serious and life threatening complications may occur with PVA. KEYWORDS: Bronchial artery emobolization; Complication; Polyvinyl alcohol.