Search Results - (Author, Cooperation:D. C. Martin)
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1Latest Papers from Table of Contents or Articles in PressD. C. Martin ; M. Matuszewski ; P. Morrissey ; J. D. Neill ; A. Moore ; S. Cantalupo ; J. X. Prochaska ; D. Chang
Nature Publishing Group (NPG)
Published 2015Staff ViewPublication Date: 2015-08-08Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsPublished by: -
2Latest Papers from Table of Contents or Articles in PressS. Gezari ; R. Chornock ; A. Rest ; M. E. Huber ; K. Forster ; E. Berger ; P. J. Challis ; J. D. Neill ; D. C. Martin ; T. Heckman ; A. Lawrence ; C. Norman ; G. Narayan ; R. J. Foley ; G. H. Marion ; D. Scolnic ; L. Chomiuk ; A. Soderberg ; K. Smith ; R. P. Kirshner ; A. G. Riess ; S. J. Smartt ; C. W. Stubbs ; J. L. Tonry ; W. M. Wood-Vasey ; W. S. Burgett ; K. C. Chambers ; T. Grav ; J. N. Heasley ; N. Kaiser ; R. P. Kudritzki ; E. A. Magnier ; J. S. Morgan ; P. A. Price
Nature Publishing Group (NPG)
Published 2012Staff ViewPublication Date: 2012-05-12Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsPublished by: -
3Latest Papers from Table of Contents or Articles in PressT. Newbold ; L. N. Hudson ; S. L. Hill ; S. Contu ; I. Lysenko ; R. A. Senior ; L. Borger ; D. J. Bennett ; A. Choimes ; B. Collen ; J. Day ; A. De Palma ; S. Diaz ; S. Echeverria-Londono ; M. J. Edgar ; A. Feldman ; M. Garon ; M. L. Harrison ; T. Alhusseini ; D. J. Ingram ; Y. Itescu ; J. Kattge ; V. Kemp ; L. Kirkpatrick ; M. Kleyer ; D. L. Correia ; C. D. Martin ; S. Meiri ; M. Novosolov ; Y. Pan ; H. R. Phillips ; D. W. Purves ; A. Robinson ; J. Simpson ; S. L. Tuck ; E. Weiher ; H. J. White ; R. M. Ewers ; G. M. Mace ; J. P. Scharlemann ; A. Purvis
Nature Publishing Group (NPG)
Published 2015Staff ViewPublication Date: 2015-04-04Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; *Biodiversity ; Conservation of Natural Resources/trends ; Ecology/trends ; History, 16th Century ; History, 17th Century ; History, 18th Century ; History, 19th Century ; History, 20th Century ; History, 21st Century ; *Human Activities ; Models, Biological ; Population Dynamics ; Species SpecificityPublished by: -
4Articles: DFG German National LicensesStaff View
ISSN: 1471-0528Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: MedicineType of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1471-0528Source: Blackwell Publishing Journal Backfiles 1879-2005Topics: MedicineNotes: Endometriosis may result in pain and/or infertility in some patients, while others may remain asymptomatic. The disease appears to progress and regress somewhat unpredictably, making it difficult to determine the appropriate treatment. Progression of the disease can be altered by medical and surgical treatments used according to general guidelines but selected for the individual. Coagulation, medical suppression and observation are frequently the first approaches to infertility or pain resulting from endometriosis. Deep dissection and excision may be indicated with deep disease, persistent pain or persistent tenderness.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] IN 1871, Mr. John Peter Gassiot conveyed to the Royal Society £10,000 of Italian Irrigation Bonds for the purpose of assisting magnetical and meteoro logical observations with self-recording instruments, primarily in the Kew Observatory. The Society set up its Gassiot Committee in the same ...Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] SMALL differences in the colour of solutions of copper sulphate and silver permanganate when dissolved in deuterium oxide instead of ordinary water have been reported by Bell1, and Hein and Bähr2 respectively. Displacement of the absorption lines in the spectrum of ...Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesStaff View
ISSN: 0958-0433Topics: Art HistoryNotes: PROCEEDINGS OF THE SOCIETYURL: -
9Articles: DFG German National LicensesMartin, J. C. ; Martin, D. C. ; Mackler, Bruce ; Grace, Richard ; Shores, Patti ; Chao, Stella
Springer
Published 1985Staff ViewISSN: 1432-2072Keywords: Prenatal drug exposure ; Shock schedules ; Sprague-Dawley rat ; Offspring growth and development ; Activity ; Phenobarbital sodium ; Pentobarbital sodiumSource: Springer Online Journal Archives 1860-2000Topics: MedicineNotes: Abstract Gravid Sprague-Dawley-derived rats were injected SC twice daily with either 20 or 40 mg/kg pentobarbital sodium (PT), sodium phenobarbital (PH), or the same volume of the saline vehicle on days 9–21 of pregnancy. Pair-feeding was employed. Vital, developmental, and activity measures were obtained on the neonates and locomotor activity was measured from 3–10 months of age. Avoidance was measured sequentially in a shuttle box, and in an operant chamber beginning at 3 months of age. The PH-80 dams gained less weight over the gestational period, and PH-80 and PH-40 offspring had more neonatal deaths. These male offspring were hyperactive at maturity, and PH-80 rats were initially slower to escape experimenter-initiated shock. PT exposure caused transient neonatal and juvenile hyperactivity. PT rats performed more poorly on both the conditioned avoidance and Sidman shock schedules, and had significantly lower brain: body weight ratios at 1 year of age. All four drug groups outperformed the saline offspring on subject-initiated shock schedules (punishment). Sex of offspring was determined on postnatal day 4 and the sex ratio was shifted towards male births with both drugs relative to controls.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesStaff View
ISSN: 1573-093XSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract A multiple entrance slit spectrograph was built for time-lapse photography of the spectra of flares and other transient solar phenomena. This spectrograph employs narrow-band filters to limit the wavelength range of the spectrograph to several angstroms centered at Hα or other spectral lines. The passband of the filter, and the dispersion of the spectrograph determine the number of parallel slits through which light may be passed to achieve multiple adjacent spectral displays. By using a 7 Å filter, a dispersion of 10.8 Å mm−1, and 35 mm film, adjacent Hα spectra are imaged from 30 parallel slits. A system of mirrors and relay lenses transfers the slitjaw image to the same film plane as the spectral image. A 2 frame camera is used to simultaneously record both images on adjacent frames. Filtering of the reference spatial image to 1.0 Å allows the observer to see the position of the slits relative to the Hα centerline structure and to match the brightness of the spatial image to the spectral display. A polarizing beamsplitter, prior to the slits, provides a prefiltered second solar image to a narrow band Hα Doppler filter for simultaneous photography in the wings of the Hα line. The multislit monochromatic spectrograph and Hα Doppler system constitute a flexible instrument in which components may be substituted to achieve different passbands width, image scales, dispersions and corresponding numbers and spacings of adjacent spectra at a selected wavelength.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] SIR,?Your leader of November 8 was critical of the line you thought the United Kingdom would be taking on the question of the International Centre for Theoretical Physics, Trieste, at the recent 18th General Conference of UNESCO, and attributed this probable attitude largely to Sir Harold Thompson ...Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesStaff View
ISSN: 1573-4803Source: Springer Online Journal Archives 1860-2000Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsNotes: Abstract The tensile strengths of fibres of the rigid-rod polymers poly(paraphenylene benzobisthiazole) (PBZT) and poly(paraphenylene benzobisoxazole) (PBZO) are excellent, and therefore are of particular interest for high-performance structural applications. However, these fibres are a factor of ten weaker in compression, with failure occurring by strain localization in welldefined kink bands. Here, we study the morphology of PBZT and PBZO kink bands in detail, in order to help elucidate the molecular mechanisms involved in this deformation process. We found that the typical dimensions of a kink in the direction of the fibre axis (∼ 30 nm) were smaller than the length of an average PBZT or PBZO molecule (100 nm). Also, the boundary between the kinked and unkinked regions was well-defined. Low-dose, high-resolution electron microscopy (HREM) of the kink interior revealed local, high-angle changes in chain orientation, indicative of covalent bond bending or breaking. The kink boundaries exhibit “sharp” or “smooth” features which seem to be related to the local tensile or compressive nature of the stress field. A model for kink nucleation and propagation in terms of partial dislocations is presented and discussed. A stress analysis using this model has been developed, and comparison with experimental data suggests that kinks tend to propagate towards regions of higher compressive stress. This observation is interpreted in terms of dislocation pinning (in areas of hydrostatic tension) and the nucleation of dislocation pairs (in areas of hydrostatic compression) due to the asymmetric nature of the intermolecular energy potential. Finally, practical methods for improving compressive strength based on these mechanistic insights are proposed.Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesHwang, C. R. ; Malone, M. F. ; Farris, R. J. ; Martin, D. C. ; Thomas, E. L.
Springer
Published 1991Staff ViewISSN: 1573-4803Source: Springer Online Journal Archives 1860-2000Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsNotes: Abstract A method for preparing composite fibres by infiltrating nylon into swollen poly(p-phenylene benzobisthiazole) (PBZT) fibre is described. PBZT fibre forms a microfibrillar network structure during the coagulation process.In-situ network composite (IC) fibres may be prepared by exchanging the coagulant with a solution containing the desired matrix material. These new composite fibres exhibit nearly identical mechanical properties and similar thermomechanical properties to those of so-called molecular composite (MC) fibres prepared from isotropic solutions of PBZT and nylon in methane sulphonic acid (MSA), The mechanical properties of these fibres were determined before and after heat treatment under tension. The structure of pure PBZT and its composite fibres (ICs' and MCs') were characterized using nitrogen adsorption (Brunauer-Emmett-Teller (BET) experiments), small-angle X-ray scattering, and scanning and transmission electron microscopy (SEM and TEM, respectively). The structure of both composite fibres was found to be a microfibrillar network of PBZT in a matrix of amorphous nylon. The average diameters of the PBZT microfibrils were in the range of 10 to 20 nm forin-situ network composites and approximately 4 nm for molecular composites.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesChow, R. S. ; Medri, M. K. ; Martin, D. C. ; Leekam, R. N. ; Agur, A. M. ; McKee, N. H.
Springer
Published 2000Staff ViewISSN: 1439-6327Keywords: Key words Gastrocnemius ; Gender ; Muscle architecture ; Soleus ; UltrasoundSource: Springer Online Journal Archives 1860-2000Topics: MedicineNotes: Abstract The purpose of this study was to establish if there are gender differences in muscle architecture in relaxed human soleus and gastrocnemius muscles of normal, live subjects. Ultrasonography was used to measure fiber bundle length, muscle thickness, and angles of pennation in a total of ten predetermined sites in the medial and lateral heads of gastrocnemius and the anterior and posterior soleus in 19 males and 16 females. Percentage differences between males and females for each parameter were recorded. Gender differences were statistically analyzed using multivariate analysis of variance. In the gastrocnemius and soleus muscles of males and females the differences between the overall fiber bundle length, angle of pennation and muscle thickness were statistically significant (P 〈 0.05). Overall, females were found to have longer average muscle fiber bundle length and males thicker muscles and larger angles of pennation. The greatest percentage differences of the architectural parameters between males and females were in the posterior soleus: 13% difference in fiber length and 26% difference in angle of pennation in the midline of posterior soleus and 26% difference in muscle thickness of the lateral part of posterior soleus. No correlation was found between leg length and fiber length, angle of pennation or muscle thickness. Fiber length (decreased), angle of pennation (greater) and muscle thickness (greater) of most parts of the gastrocnemius and soleus muscles were significantly different in males and females. Leg length of males and females did not correlate to these architectural parameters.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesStaff View
ISSN: 1573-4803Source: Springer Online Journal Archives 1860-2000Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsNotes: Abstract A study has been conducted on the compressive deformation behaviour of thermally cross-linkable poly(p-1,2-dihydrocyclobuta phenylene terephthalamide) (PPXTA) fibres. The morphology of the failure zones was examined by scanning electron microscopy and dark-field transmission electron microscopy. On increasing the heat-treatment temperature from 260–400°C, and therefore with increasing cross-link density, fewer kinks per unit length were displayed after compressive deformation. The kink specific energy was estimated to increase by a factor of 30, as determined by quantitative measurements of kink density at a given strain and of the critical strain to kink formation. Thus, the intermolecular cross-links still allowed deformation to proceed by kinking, but significantly raised the energy of kink formation. Finally, rupture zones were predominantly observed in axially compressed PPXTA fibres heat-treated at 440°C. Compressive failure of the fibres changed from kink-dominated failure to brittle rupture with increased heat-treatment temperature, evidently as the result of cross-linking or of chain degradation. A dislocation model of the kink boundary developed by Vladimirov et al. was analysed and critically compared with our data. The analysis of this theory with our experimental results suggested that the dramatic change in compressive behaviour with cross-linking was due to a transition from fine intermolecular shear to blocky interfibrillar shear.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesStaff View
ISSN: 1573-4803Source: Springer Online Journal Archives 1860-2000Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsNotes: Abstract The lateral deformation properties of oriented polymer fibres were examined by transverse compressive and torsional experiments. A modified interfacial test system machine was used to study the transverse compressive deformation behaviour of thermally cross-linkable poly(p-1,2-dihydrocyclobutaphenylene terephthalamide) (PPXTA) fibres and of a number of commercially available polymers (Nomex, nylon, Kevlar, Dacron) and ceramic (Nicalon and FP) fibres. The torsional (shear) modulus G of PPXTA and Kevlar poly(p-phenylene terephthalamide) (PPTA) fibres was measured by pendulum experiments. During both fibre torsion and transverse compression, the deformation involves materials slip on (h k 0) planes, in the [0 0 1] direction for the torsion and the [h k 0] directions for transverse compression. The intermolecular crosslinks in PPXTA did not significantly modify the elastic transverse modulus Et and caused only slight (13%) increase in shear modulus G. However, the plastic transverse properties of cross-linked PPXTA were significantly different than those of uncross-linked PPXTA. The stress at the proportional limit σp, determined from the transverse load–displacement curves, was substantially higher for the cross-linked fibres than for the uncross-linked fibres. In addition, the cross-linked PPXTA fibres exhibited a large strain recoverable response reminiscent of elastomers, whereas the PPTA and uncross-linked PPXTA fibres exhibited a large strain irreversible response.Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesStaff View
ISSN: 0021-8995Keywords: Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyMechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision MechanicsPhysicsNotes: This study was undertaken to determine how milled glass fibers affect the fatigue resistance of reaction injection molded (RIM) nylon 6. Specifically the effects of glass content, fiber length, orientation, and surface treatment were investigated. The fatigue crack growth rates for unfilled and glass-filled samples were observed to follow the well-known Paris equation in terms of dependence on cyclic stress intensity factor. For the unfilled nylon a line shaped zone was observed in advance of the crack tip. Fractography results suggest that the zone was the projection of the actual crack tip profile through the thickness of the sample rather than a distinct plastic or deformation zone. The fatigue fracture surface exhibited a patchy type structure with features 50-150 μm in size, suggesting a void coalescence type of mechanism as has been reported for injection molded nylons. A diffuse damage zone, several millimeters in size, was observed at the crack tip for the glass-filled RIM nylon 6. The zone was observed to pulsate with the applied oscillating load. The growth of the damage zone volume with increasing crack length (and thus increasing stress intensity factor range) followed the Paris law, as did the crack growth rate data. The damage mechanism is attributed to void formation and microcracking at the fiber-matrix interface. The results of this study show that, for milled glass-reinforced RIM nylon 6, the crack growth rates were much more rapid than observed for injection-molded nylon 6 containing chopped glass fibers. This difference is attributed to the greatly reduced glass fiber lengths for the milled glasses.Additional Material: 19 Ill.Type of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesPiner, R. ; Reifenberger, R. ; Martin, D. C. ; Thomas, E. L. ; Apkarian, R. P.
New York : Wiley-Blackwell
Published 1990Staff ViewISSN: 0887-6258Keywords: Chemistry ; Polymer and Materials ScienceSource: Wiley InterScience Backfile Collection 1832-2000Topics: Chemistry and PharmacologyNotes: The scanning tunneling microscope has been used to image single crystal polyethylene lamellae coated with thin Au or Cr overlayers. The images show a variety of different morphologies ranging from single crystal lamella resting on atomically flat, highly oriented pyrolitic graphite substrates to large pyramidal structures formed by a multilayer growth process. Small outgrowth structures were observed on the top surface of many individual lamellae and were found to be in registry with the edge of the underlying “seed” lamella. The STM studies show evidence for sectorization of the single crystal lamella as well as plastic deformation of overlapping lamellae involving c-axis slip.Additional Material: 6 Ill.Type of Medium: Electronic ResourceURL: