2,381 research outputs found
"The 'fightin'est' Canadian general:" Brigadier Christopher Vokes and his approach to military command, June 1942 -- August 1943
No full textThis thesis evaluates the manner in which Brigadier Christopher Yokes dealt with the technical and human aspects of command while commanding the 2nd Canadian Infantry Brigade from 25 June 1942 until the end of the Sicilian campaign in August 1943. It seeks to promote a greater understanding of brigade-level command and to rehabilitate Vokes's reputation as a commander, which has largely been based on certain negative personality traits. The author argues that Yokes was a successful commander because he maintained a good balance between technical skills such as planning and directing operations and his ability to understand, motivate, and lead soldiers, and because his actions were guided by a sound philosophy of command based on personal leadership and teamwork. These elements allowed Christopher Yokes to train and lead a highly effective and cohesive fighting force that defeated some of Germany's best troops in the physically demanding environment of the Sicilian battlefield
"The 'fightin'est' Canadian general:" Brigadier Christopher Vokes and his approach to military command, June 1942 -- August 1943
No full textThis thesis evaluates the manner in which Brigadier Christopher Yokes dealt with the technical and human aspects of command while commanding the 2nd Canadian Infantry Brigade from 25 June 1942 until the end of the Sicilian campaign in August 1943. It seeks to promote a greater understanding of brigade-level command and to rehabilitate Vokes's reputation as a commander, which has largely been based on certain negative personality traits. The author argues that Yokes was a successful commander because he maintained a good balance between technical skills such as planning and directing operations and his ability to understand, motivate, and lead soldiers, and because his actions were guided by a sound philosophy of command based on personal leadership and teamwork. These elements allowed Christopher Yokes to train and lead a highly effective and cohesive fighting force that defeated some of Germany's best troops in the physically demanding environment of the Sicilian battlefield
Protein crystal screening and characterization for serial femtosecond nanocrystallography
No full textGet it at UQ Library| Export | Download | Add to List | More... Scientific Reports Volume 6, 3 May 2016, Article number 25345 Open Access Protein crystal screening and characterization for serial femtosecond nanocrystallography (Article) Darmanin, C.a , Strachan, J.a, Adda, C.G.b, Ve, T.cd, Kobe, B.c, Abbey, B.ae a ARC Centre of Advanced Molecular Imaging, Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia b Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia c School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience, Division of Chemistry and Structural Biology, Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia View additional affiliations View references (19) Abstract The recent development of X-ray free electron lasers (XFELs) has spurred the development of serial femtosecond nanocrystallography (SFX) which, for the first time, is enabling structure retrieval from sub-micron protein crystals. Although there are already a growing number of structures published using SFX, the technology is still very new and presents a number of unique challenges as well as opportunities for structural biologists. One of the biggest barriers to the success of SFX experiments is the preparation and selection of suitable protein crystal samples. Here we outline a protocol for preparing and screening for suitable XFEL targets
Founders: Christopher Taylor
No full text\ua9 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. ‘Founders’ is an intermittent series of short, critical appreciations of scholars, researchers and others whose work and ideas, mainly in Britain, have made particularly sweeping, influential and foundational contributions to the development of historically- and archaeologically-informed landscape studies. This latest addition to the series concerns Christopher Taylor, whose death on 28th May 2021 was noted in the Landscapes editorial in issue 21.2
Pannexin-1 and P2X7-Receptor Are Required for Apoptotic Osteocytes in Fatigued Bone to Trigger RANKL Production in Neighboring Bystander Osteocytes
No full textOsteocyte apoptosis is required to induce intracortical bone remodeling after microdamage in animal models, but how apoptotic osteocytes signal neighboring “bystander” cells to initiate the remodeling process is unknown. Apoptosis has been shown to open pannexin-1 (Panx1) channels to release adenosine diphosphate (ATP) as a “find me” signal for phagocytic cells. To address whether apoptotic osteocytes use this signaling mechanism, we adapted the rat ulnar fatigue-loading model to reproducibly introduce microdamage into mouse cortical bone and measured subsequent changes in osteocyte apoptosis, receptor activator of NF-kB ligand (RANKL) expression and osteoclastic bone resorption in wild-type (WT; C57Bl/6) mice and in mice genetically deficient in Panx1 (Panx1KO). Mouse ulnar loading produced linear microcracks comparable in number and location to the rat model. WT mice showed increased osteocyte apoptosis and RANKL expression at microdamage sites at 3 days after loading and increased intracortical remodeling and endocortical tunneling at day 14. With fatigue, Panx1KO mice exhibited levels of microdamage and osteocyte apoptosis identical to WT mice. However, they did not upregulate RANKL in bystander osteocytes or initiate resorption. Panx1 interacts with P2X7R in ATP release; thus, we examined P2X7R-deficient mice and WT mice treated with P2X7R antagonist Brilliant Blue G (BBG) to test the possible role of ATP as a find-me signal. P2X7RKO mice failed to upregulate RANKL in osteocytes or induce resorption despite normally elevated osteocyte apoptosis after fatigue loading. Similarly, treatment of fatigued C57Bl/6 mice with BBG mimicked behavior of both Panx1 KO and P2X7RKO mice; BBG had no effect on osteocyte apoptosis in fatigued bone but completely prevented increases in bystander osteocyte RANKL expression and attenuated activation of resorption by more than 50%. These results indicate that activation of Panx1 and P2X7R are required for apoptotic osteocytes in fatigued bone to trigger RANKL production in neighboring bystander osteocytes and implicate ATP as an essential signal mediating this process.Peer reviewe
The effects of estrogen deficiency on cortical bone microporosity and mineralization
No full textRecent studies have demonstrated matrix-mineral alterations in bone tissue surrounding osteocytes in estrogen-deficient animals.While cortical bone porosity has been shown to be a contributor to the mechanical properties of bone tissue, little analysis has been done to investigate the effects of estrogen deficiency on bone's microporosities, including the vascular and osteocyte lacunar porosities. In this study we examined alterations in cortical bone microporosity, mineralization, and cancellous bone architecture due to estrogen deficiency in the ovariectomized rat model of postmenopausal osteoporosis. Twenty-week-old female Sprague–Dawley rats were subjected to either ovariectomy or sham surgery. Six weeks post-surgery tibiae were analyzed using high-resolution micro-CT, backscattered electron imaging, nanoindentation, and dynamic histomorphometry. Estrogen deficiency caused an increase in cortical bone vascular porosity, with enlarged vascular pores and little change in tissue mineral density in the proximal tibial metaphysis. Measurements of cancellous architecture corresponded to previous studies reporting a decrease in bone volume fraction, an increase in trabecular separation, and a decrease in trabecular number in the proximal tibia due to estrogen deficiency. Nanoindentation results showed no differences in matrix stiffness in osteocyte-rich areas of the proximal tibia of estrogen-deficient rats, and bone labeling and backscattered electron imaging showed no significant changes in mineralization around the vascular pores. The findings demonstrate local surface alterations of vascular pores due to estrogen deficiency. An increase in cortical vascular porosity may diminish bone strength as well as alter bone mechanotransduction via interstitial fluid flow, both of which could contribute to bone fragility during postmenopausal osteoporosis.Peer reviewe
Heritability and Linkage Analysis of Appendicitis Utilizing Age at Onset
No full textAppendicitis usually afflicts the young, but there is a large tail in the distribution of onset age. The genetics of this disease are still not well understood. A heritability analysis and genome wide linkage analysis of a large twin dataset was undertaken. Treating age of onset of appendicitis as a censored survival trait revealed a heritability of 0.21, and found evidence of linkage to Chromosome 1p37.3. Author(s): Christopher Oldmeadow 1 * | Kerrie Mengersen 2 | Nicholas Martin 3 | David L. Duffy
Evaluation of transmission infrared spectroscopy and digital and optical refractometers to identify low immunoglobulin G concentrations in alpaca serum.
No full textThis study aimed to evaluate the digital Brix and optical serum total protein (STP) refractometers for measuring concentrations of serum immunoglobulin G (IgG) in alpacas and compare them to IgG concentrations measured by the reference method of radial immunodiffusion (RID) assay. The appropriate cutoff point for Brix and STP refractometers and the transmission infrared (TIR) spectroscopy method was determined for low IgG concentrations (< 10 g/L). Serum samples were collected from alpacas (N = 169) and tested by both refractometers. The correlation between Brix % and STP was high [correlation coefficient (r) = 0.99]. However, the correlation coefficients between Brix % and STP with serum RID-IgG concentrations were only 0.56 and 0.55, respectively. Twenty-one (12.4%) of 169 alpaca serum samples had IgG concentrations of < 10 g/L. Using receiver operator characteristic curve (ROC) analysis, the optimal cutoff points for the TIR assay, digital Brix, and optical STP refractometers for assessing low IgG (RID < 10 g/L) were 13 g/L, 8.8%, and 50 g/L, respectively. The TIR assay showed higher sensitivity (Se = 95.2%) and specificity (Sp = 96.8%) than either the digital Brix (Se = 90.5% and Sp = 65.5%) or optical STP (Se = 81% and Sp = 73.7%) refractometers for assessing alpacas with low IgG. In conclusion, the Brix and STP refractometers lack accuracy in measuring alpaca IgG concentrations, but may be useful for screening animals for low serum IgG. However, the TIR assay with a cutoff point of 13 g/L was more appropriate for identifying low IgG than either refractometer. Another study that focuses on neonatal crias is recommended in order to evaluate the usefulness of these assays for field diagnosing of failure of transfer of passive immunity (FTPI).journal article2017 Julimporte
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No full textii for Karen, my friend, my con dant, my wife. iii iv Acknowledgements The author would like to thank his advisor, Dr. Ronald C. Arkin, for directly supporting this research and for support encompassing the entire period of his enrollment. Special thanks are given to the other committee members: Dr. Christopher G. Atkeson, Dr. Richard J. Leblanc, Dr. Wayne J. Book, and Dr. John T. Stasko for the helpful advice given during the progression of this research and for the time spen
Detecting intestinal ischemia using near infrared spectroscopy
No full textBlood supply to the intestine can suddenly be interrupted. Acute mesenteric intestinal ischemia often requires invasive surgery to restore blood supply to the intestine. Early correction of vascular insufficiency is the most important factor in improving patient survival when confronted with acute mesenteric intestinal ischemia. A prolonged loss of blood flow results in irreversible damage to the intestine that can lead to death. It is also imperative that dead segments of the intestines be removed. Several subjective criteria are relied upon to differentiate viable from non-viable tissue, unfortunately, these criteria can lead to an inaccurate assessment. A porcine model of intestinal ischemia was used to determine the efficacy of using near infrared (NIR) spectroscopy to find ischemic segments of the intestine and detect the onset of reperfusion following resolution of vascular occlusion. Nine segments of intestine were identified and six were assigned to three treatment groups; (1) segments undergoing no vascular manipulations, (2) segments undergoing arterial/venous occlusion and (3) segments undergoing arterial/venous occlusion followed by reperfusion. The remaining segments were used as spacers and interposed between each of the ischemia segments. A classification model, using partial least square discriminant analysis, was built on the spectra collected from the segments with no vascular manipulations and the segments that were solely subjected to arterial/venous occlusion. The spectra collected from the intestinal segments that experienced both occlusion and reperfusion were used to test the classification model. The model was able to detect and distinguish ischemic intestinal tissue with a specificity and sensitivity exceeding 80% with an overall classification accuracy of 89%. The method appears to be well suited as an intra-operative assessment method when intestinal ischemia is a concern.Michael G. Sowa, Elicia Kohlenberg, Jeri R. Payette, Lorenzo Leonardi, Michelle A. Levasseur and Christopher B. Rile
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