75 research outputs found
Identification of a key regulatory pathway in bone regeneration using a novel mouse fracture model
No full textFracture healing is the complex biological process that restores broken bones to their original shape and function. While the fracture repair process follows a definitive sequence of events, not all the molecular or chemical pathways are completely understood. The development of animals with targeted mutations has allowed for the examination of specific fracture healing pathways, making the use of the mouse model an increasingly valuable tool in the field of orthopaedics. Additionally, evaluating the healing tissues using a torsional mechanical testing protocol is more reproducible and provides a better estimate of the biomechanical properties. Therefore, the first section of this dissertation is focused on the development and characterization of a murine femoral fracture model suitable for torsional mechanical testing. The model developed was tested using radiography, histology and mechanical testing and was shown to be comparable to other published femoral fracture models. After validation of this model, the next experiment focused on exploring how a complex phenotype, such as bone mineral density, may affect bone healing. Using inbred strains of mice with established bone mineral density values, the radiographic, histologic and biomechanical analyses of the healing femurs were evaluated. This data showed that having a high bone mineral density actually results in lower mechanical properties and therefore may be deleterious to fracture repair. Finally, this mouse fracture model was used to see how altering the arachidonic acid pathway affects fracture healing. Using genetically modified mice and the fracture and mechanical testing protocols as described, the role of the arachidonic acid pathway in fracture repair was examined. This data showed that either inhibition or acceleration of fracture repair is achieved by manipulating this pathway.Ph.D.Includes bibliographical references (p. 154-175)
De maiori personarum illustrium aetate
No full textQuam ... Praeside ... Joanne Michaele Dahm ... Publicae Eruditorum Censurae Exponit Author Et Respondens Anselmus Franciscus Lieb, Mogonus in Audit. Acad. Moguntiae Die [ ] an. MDCCLVII.Vorlageform des Erscheinungsvermerks: Moguntiae, ex Typogr. Elector. Aulic. Acad. apud Haer. Haeffner, Per Joann. Benjam. WaylandtDatum fehlt im DruckMainz, Jur. Diss., 28. Juli 175
Hydrogen isotope ratios measurements by Penning gauge spectroscopy of molecular Fulcher-α band
No full textPenning gauge spectroscopy of Balmer-α lines of hydrogen isotopes is widely used in fusion experiments to determine the hydrogen isotope ratios and the partial pressures in the pump duct. The Balmer-α line isotopic shifts are very small < 0.176 nm and the lines partially overlap because of the presence of energetic atoms produced by molecular dissociation. The ro-vibrational emission bands of each hydrogen isotopomer consist of many narrow spectral lines, covering a wide wavelength span and have an unique signature. To investigate the capability of the hydrogen molecular spectroscopy for the isotopic ratio determination, an Alcatel-type Penning gauge was coupled by the optical fiber to the Echelle spectrometer having 365–715 nm spectral range and the spectral resolving power above 20,000. The intensities of both atomic Balmer-α lines and molecular Fulcher-α bands were measured in the range of 6·10−6 – 4·10-3 mbar. The rotational and vibrational populations were almost independent of the gas pressure below 2·10-4 mbar. The total intensities of the Fulcher-α molecular bands were linearly proportional to the gas pressure. The H2 and D2 molecular emission in 599–639 nm spectral range were in a good agreement with the isotopic composition of the used gas mixtures
Improving accuracy of Penning gauge spectroscopy for the determination of hydrogen isotope H/D ratios
No full textAtomic spectral lines emitted from a Penning discharge are often used to quantify partial pressures and isotopes ratios in gases. To identify the potential of this method for thermal desorption studies, the hydrogen emission spectrum lines (Hα and Dα) were examined by an Alcatel Penning gauge. The hydrogen/deuterium pressures were measured by both a capacitive vacuum gauge and the Penning gauge. Different gas mixtures were produced by varying of hydrogen/deuterium flows. The Balmer-alpha lines intensities were recorded with help of a high etendue spectrometer coupled to the Penning gauge using relay optics together with fiber bundle and equipped with Peltier cooled CCD camera. Subsequent measurements using hydrogen and deuterium gases revealed for identical pressures in the range of 10−6–10−3 mbar that the Hα line intensities are systematically higher the Dα line intensities by a factor of 1.28 ± 0.01. This observation can be explained by the dissociative excitation of the molecular hydrogen by electron impact. In addition the Hα line intensity for the H2 gas having constant partial pressure is slightly increased with total gas mixture pressure. Taking into account of both effects essentially improves the accuracy of the determination of partial pressures and isotope H/D ratios
Corporate computer gifts expand college resources. By Michaele Wilk Houston
No full texthttps://rdc.reed.edu/v1/resources/f7befb62-15ab-4b18-89a1-8d1cd3312a75/thumb/128.jpgArticle about an earlier hardware gift to the college of illegal pinball machines which, in the early 1960s, chemistry professor John Hancock proceded to dismantle and use the parts in his DIMWIT I (Dodecahedron Isomer Machine with Internal Translation), a forerunner of the computer. The author, director of corporation and foundation gifts, goes on to tell the rest of the history of computers at Reed up to the present
Fuel re-absorption by thermally treated co-deposited carbon layers
No full textSystematic studies have been conducted to address the fuel re-absorption by carbon deposits under repeated exposure to plasma after cleaning procedures. The investigation was done with graphite tiles from ALT-II (Advanced Limiter Test II), i.e. the main limiter at the TEXTOR tokamak. Pure graphite plates were used as the reference material. The experimental programme comprised the following: pre-characterization of specimens; D desorption by baking the tile at 1273 K; surface analyses of the fuel-depleted layers; exposure to deuterium in a laboratory plasma device and in TEXTOR; and quantitative assessment of deuterium re-absorption. The main result is that fuel retention in the re-exposed deposits is 30-40 times lower than that in the original co-deposit, showing that fuel re-absorption does not lead to an immediate re-saturation of deposits. Annealing at high temperatures enhances layer brittleness, leading eventually to detachment of co-deposits
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Tractatvs regiminis mvndi authore Michaele Vlcurruno pampilon. i. v. d. quem tractatum ipse author opus imperiale inscripsit.
No full textMichał Savonarola on a difficult childbirth in <i>Ad mulieres Ferrarienses de regimine pregnantium et noviter natorum usque ad septennium</i>
No full textMichaele Savonarola’s treatise Ad mulieres Ferrarienses de regimine pregnantium et noviter natorum usque ad septennium is one of the most important treatises on gynecology, obstetrics and pediatrics written in Italy of 15th century. Its author combined the high mortality of women and children with the low qualifications of the midwives of that time and to rise the level of their knowledge he wrote a treatise which was a kind of the guide through pregnancy, difficulties during birth and care of children from birth until he was seven. Numerous references to the earlier authors testify the Savonarola’s great theoretical knowledge and accurate observation about the medical practice. Even though many of the perinatal complication described by him had already been mentioned by Arnald de Villanova, the language used by Savonarola, the way of explanation of the undertaken problems and numerous advices made the treatise available to midwives who had no medical education but on whose knowledge and skills depended the lives of women and children
Fuel Retention Diagnostic Setup (FREDIS) for desorption of gases from beryllium and tritium containing samples
No full textIn fusion devices, the retention of the fusion fuel deuterium (D) and tritium (T) in plasma-facing components (PFCs) is a major concern. Measurement of their hydrogen isotope content gives insight into the retention physics.In FREDIS, two methods of thermal desorption are used for retention measurements: In Thermal Desorption Spectrometry (TDS) the samples are heated by 6 infrared lamps up to 1433 K with linear temperature ramps of up to 1.67 K/s. The desorbed gases are detected up to 100 amu/e with a double-QMS (Quadrupole Mass Spectrometer) that can distinguish between helium and D2 and uses an innovative differential pumping system.In a connected vacuum chamber, a ∅3 mm spot can be heated on the sample surface by a high energy Nd:YAG laser pulse (E0 < 100 J) within milliseconds (0.1–20 ms) to several thousand degrees. This method of Laser-Induced Desorption (LID) can also be applied inside the fusion chamber and is planned as in situ retention diagnostic for ITER. In FREDIS, LID is thus tested and used as ex situ analysis method utilising the same double-QMS for absolute quantification. FREDIS is capable of handling beryllium (Be) by means of glove boxes and in the future also tritium using a tritium trap to analyse also samples from JET and ITER. In this contribution we present the specifications of FREDIS and compare TDS and LI
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