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Glass Tubes (glass + tubes)
Selected AbstractsOlfactory cues and nest recognition in the solitary bee Osmia lignariaPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2006Christelle Guédot Abstract., The use of olfactory cues for nest recognition by the solitary bee Osmia lignaria is studied in a greenhouse environment. Glass tubes are provided as nesting cavities to allow the in-nest behaviour of bees to be observed. In addition, each glass tube is cut into three sections for experimental manipulation and for subsequent chemical analysis. Nesting females drag their abdomen along the tube before exiting, spiral inside the tube, and sometimes deposit fluid droplets from the tip of the abdomen. For the manipulation, the outer section, the middle section, or both sections are removed and replaced with similar clean glass tube sections, and the behaviour exhibited by test females is recorded upon arrival in front of the nesting site and inside the nesting tubes. The resulting hesitation behaviour displayed by females after treatments appears to indicate the loss of some olfactory cues used for nest recognition inside the entire nest. Chemical analysis of the depositions inside the nesting tube, as well as analysis of the cuticular lipids of the nesting bees, reveals the presence of free fatty acids, hydrocarbons and wax esters. [source] Role of substrate material in failure of crown-like layer structures,JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007Jae-Won Kim Abstract The role of substrate modulus on critical loads to initiate and propagate radial cracks to failure in curved brittle glass shells on compliant polymeric substrates is investigated. Flat glass disks are used to drive the crack system. This configuration is representative of dental crown structures on dentin support in occlusal contact. Specimens are fabricated by truncating glass tubes and filling with epoxy-based substrate materials, with or without alumina filler for modulus control. Moduli ranging from 3 to 15 GPa are produced in this way. Critical loads for both initiation and propagation to failure increase monotonically with substrate modulus, by a factor of two over the data range. Fracture mechanics relations provide a fit to the data, within the scatter bands. Finite element analysis is used to determine stress distributions pertinent to the observed fracture modes. It is suggested that stiffer substrate materials offer potential for improved crown lifetime in dental practice. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Corrosion behaviour of high copper dental amalgamsJOURNAL OF ORAL REHABILITATION, Issue 6 2004A. U. J. Yap summary, This study evaluated the corrosion behaviour of two high copper dental amalgam alloys [Dispersalloy (Dentsply-Caulk) and Tytin (Kerr)] in different electrolytes. Amalgam specimens were prepared, coupled to a copper wire, cemented into glass tubes and polished to a 600-grit finish. A corrosion cell was prepared using a carbon counter-electrode, a standard calomel electrode as the reference and amalgam as the working electrode. The alloys were tested in the following mediums at 37 °C: (i) artificial saliva based on Fusayama's solution (FS), (ii) artificial saliva with citric acid adjusted to pH 4·0 (FC) and (iii) 1% sodium chloride solution (SC). Corrosion potentials (Ecorr) and corrosion rates (Icorr) were determined using potentiostatic and impedance spectroscopy methods. Data was subjected to anova/Scheffe's post hoc test at 0·05 significance level. For both alloys, the corrosion potential in FS was significantly greater than in SC. Corrosion potential of Tytin in FS and SC was also significantly greater than in FC. The corrosion rate of Dispersalloy in FC was significantly greater than in FS and SC. For Tytin, corrosion rate in SC was significantly greater than in FS and FC. Although no significant difference in corrosion potential/rate was observed between the alloys when tested in FS, significant differences were observed when electrochemical testing was carried out in FC and SC. The corrosion behaviour of high copper amalgam alloys are both material and environment dependent. Certain food substances may increase the corrosion of high copper amalgams. [source] Side-firing sealing caps for hollow optical fibersLASERS IN SURGERY AND MEDICINE, Issue 8 2006Tomonori Watanabe BS Abstract Background and Objectives Hollow optical fibers are useful for delivery of high-energy infrared laser beam such as Er:YAG lasers. We propose side-firing optics for hollow optical fibers for laser endoscopic applications mainly in oto-rhino-laryngology and urology. Study Design/Materials and Methods To produce a circular beam, cone-shaped caps are designed and caps with slanted end are proposed for producing a spot beam in side direction. Both types of caps are fabricated by fusing and polished Pyrex and silica glass tubes. Results For the both of the cone-shaped and slanted-end caps effectively deflect laser beam as designed and these caps show high durability for Er:YAG laser light with pulse energy higher than 100 mJ. Conclusions By choosing the proper shape of the cap ends, these caps deflect an input laser beam to a preferred direction at low insertion losses. By using these side-firing optics, one can easily irradiate the inside of tubular organs. Lasers Surg. Med. 38:792,797, 2006. © 2006 Wiley-Liss, Inc. [source] Luteolytic Effect of Prostaglandin F2, on Bovine Corpus Luteum Depends on Cell Composition and ContactREPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2008AJ Korzekwa Contents Prostaglandin F2, (PGF2,) is a main luteolytic factor in vivo; however, its direct luteolytic influence on steroidogenic cells of bovine corpus luteum (CL) is controversial and not fully understood. The aim of the study was to clarify PGF2, action on bovine CL in different in vivo and in vitro conditions and to examine whether the contact among all main types of CL cells is necessary for luteolytic PGF2, action. In experiment 1, the bovine CL (day 15 of the oestrous cycle) was perfused using in vivo microdialysis system with dinoprost (an analogue of PGF2,) for 0.5 h. Dinoprost caused a short-time increase in progesterone (P4), whose concentration decreased thereafter (at 6-, 10-, 12- and 24-h after treatment). In experiment 2, the direct effect of PGF2, on P4 accumulation in CL steroidogenic cells cultured in monolayer (day 15 of the cycle) was determined. PGF2, after 24 h of incubation increased P4 accumulation in steroidogenic CL cells. In experiment 3 steroidogenic, endothelial CL and immune cells (day 15 of the cycle) were incubated with PGF2, in cocultures for 24 h in glass tubes and the levels of P4, stable metabolites of nitric oxide (NO) and leukotriene (LT) C4 were determined. Although PGF2, treatment increased P4 secretion in homogeneous steroidogenic CL cell culture, the decrease in P4 secretion in cocultures of all types of CL cells was observed. The secretion of NO and LTC4 increased after the treatment of PGF2, both in pure cultures of CL cells and in cocultures. The interactions between endothelial and immune cells with steroidogenic CL cells are needed for luteolytic PGF2, action within the bovine CL. Our results indicate that the cell coculture model, including the main types of CL cells, is the most approximate to study PGF2, role in vitro. [source] | ||||||||||