Implementation of an automatic mapping tool for massively parallel computing

In this thesis, an implementation of a generic technique for fine grain mapping of portable parallel algorithms onto multiprocessor architectures is presented. The implemented mapping algorithm is a component of Cluster-M. Cluster-M is a novel parallel programming tool which facilitates the design and mapping of portable softwares onto various parallel systems. The other components of Cluster-M are the Specifications and the Representations. Using the Specifications, machine independent parallel algorithms are presented in a clustered fashion specifying the concurrent computations and communications at every step of the overall execution. The Representations, on the other hand, are a form of clustering the underlying architecture to simplify the mapping process. The mapping algorithm implemented and tested in this thesis is an efficient method for matching the Specification clusters to the Representation clusters

Intrinsic Anthropometric Factors Associated with Bone Stress Injuries in Collegiate Runners: New Risk Metrics & Novel Field Screening Tools

Lower extremity bone stress injuries (BSI) (i.e. pelvis, femur, tibia) are common in distance running athletes relative to other sports. PURPOSE: To (1) characterize bone mineral density (BMD), body composition (BComp, DXA), and anthropometric parameters in D1A collegiate runners presenting with and without BSIs during a collegiate season and (2) develop BMD prediction models with an accompanying mobile application for novel noninvasive field prediction of BMD and BSI risk. METHODS: Distance runners (n = 79; 42♂, 37♀) from a single university track and field team were retrospectively enrolled into study. The runners completed a DXA scan during fall screening (August-November). Three months after scanning, medical records were reviewed for the occurrence of BSI confirmed by a licensed physician. A t-test was used to compare BMD (total and regional [spine, pelvis, and legs]), BComp (% body fat, fat mass, and lean mass), and anthropometric measurements (shoulder width and leg, arm, and trunk length) between runners with versus without BSI (included subgroup analysis by sex). Multiple linear regression with stepwise removal was used to determine variables most predictive of BMD. Xcode (Apple Inc.) was used to develop the mobile application based on the derived BMD prediction models utilizing lower-bound 95% confidence intervals for runner-specific BMD norms as risk cutoffs. RESULTS: Eighteen runners (22.8%; 11♀, 7♂) sustained a lower limb BSI. Compared to the noninjured group (NoBSI), injured runners (BSI) had lower total BMD (NoBSI: 1.24 0.02, BSI: 1.15 0.04, p\u3c0.001) and regional BMD (spine -11%, legs -9%, pelvis -10%, p\u3c0.001). Injured athletes were observed to have shorter leg length (NoBSI: 95.6 1.4cm, BSI: 91.9 2.6cm, p=0.015) and arm length (NoBSI: 56.1 0.8, BSI: 53.8 1.5, p=0.006). Injured males had lower fat mass (NoBSI: 7.7 0.5kg, BSI: 6.4 0.7cm, p=0.041) and injured females had lower leg lean mass (NoBSI: 14.7 0.6kg, BSI: 13.5 0.7kg, p=0.035). BComp and anthropometric measures were predictive of bone mass (p\u3c0.05, R2 =0.61; SE= ±0.27kg) and BMD (Total: p\u3c0.05, R2 =0.77; SE= ±0.05g/cm2). BONE MASS, kg = (0.046 x Ageyears) +(0.024 x Weightkg) +(0.014 x %BodyFat) +(-0.017 x Arm Lengthcm) +(0.017 x Shoulder Widthcm) +(-0.009 x Trunk Lengthcm) +(0.037 x Leg Lengthcm) -2.867] | BMD, g cm2 =(-0.011 x %BodyFat) + (0.016 x Fat Mass kg) + (0.203 x Bone Masskg) +(-0.003 x Leg Lengthcm) +1.023. The mobile application was able to successfully run the developed prediction models for BMD assessment. CONCLUSION: Collegiate distance runners with shorter limb lengths, reduced fat mass(♂), reduced leg lean mass(♀), and lower BMD are at an increased risk for a lower extremity BSI. BComp and anthropometric measures are predictive of BMD in this population and may be utilized with the mobile application developed here as a screening tool to identify potentially “at-risk” runners

Absence of system xc⁻ on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

Background: Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x(c)- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. Methods: Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x(c)-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT(-/-)) mice and irradiated mice reconstituted in xCT(-/-) bone marrow (BM), to their proper wild type (xCT(+/+)) controls. Results: xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT(+/+) mice, xCT(-/-) mice were equally susceptible to EAE, whereas mice transplanted with xCT(-/-) BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. Conclusions: Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x(c)- on immune cells invading the CNS participates to EAE. Since a total loss of system x(c)- had no net beneficial effects, these results have important implications for targeting system x(c)- for treatment of MS

Adenosine and lymphocyte regulation

Adenosine is a potent extracellular messenger that is produced in high concentrations under metabolically unfavourable conditions. Tissue hypoxia, consequent to a compromised cellular energy status, is followed by the enhanced breakdown of ATP leading to the release of adenosine. Through the interaction with A2 and A3 membrane receptors, adenosine is devoted to the restoration of tissue homeostasis, acting as a retaliatory metabolite. Several aspects of the immune response have to be taken into consideration and even though in general it is very important to dampen inflammation, in some circumstances, such as the case of cancer, it is also necessary to increase the activity of immune cells against pathogens. Therefore, adenosine receptors that are defined as ‘sensors–of metabolic changes in the local tissue environment may be very important targets for modulation of immune responses and drugs devoted to regulating the adenosinergic system are promising in different clinical situations

Curved plate damper test and simulations with snubbers, through- flow, and flexible plate effects

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