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Modern data centers are increasingly using shared storage solutions for ease of management. Data is cached on the client side on inexpensive and high-capacity flash devices, helping improve performance and reduce contention on the storage side. Currently, write-through caching is used because it ensures consistency and durability under client failures, but it offers poor performance for write-heavy workloads. In this work, we propose two write-back based caching policies, called write-back flush and write-back persist, that provide strong reliability guarantees, under two different client failure models. These policies rely on storage applications such as file systems and databases issuing write barriers to persist their data, because these barriers are the only reliable method for storing data durably on storage media. Our evaluation shows that these policies achieve performance close to write-back caching, while providing stronger guarantees than vanilla write-though caching.

Successful antiretroviral (ARV) treatment is associated with suppression of HIV viral load and the reduction of clinical disease progression. Despite marked improvements in ARV medication, side effects from long-term treatment, such as loss of muscle mass do occur. The mechanism by which ARVs affect muscle mass is unclear, however, published in vitro data suggests a negative effect on myoblast fusion during differentiation. The objective of this study was therefore to determine the effect of ARVs on processes required for successful myogenesis; these included proliferation, migration during wound repair, and differentiation. C2C12 mouse skeletal myoblasts and human primary culture skeletal (HSk) myoblasts were incubated with Zidovudine (nucleoside reverse transcriptase inhibitor-NRTI), Tenofovir (nucleotide reverse transcriptase inhibitor-NtRTI) or Ritonavir (protease inhibitor-PI) at a concentration range of 0.01 μM to 10 μM. Proliferation was determined using crystal violet and migration was analyzed using a 2D wound healing assay. The commitment of myoblasts into the myogenic lineage was assessed via the expression of the transcription factor Pax7. Differentiation was measured by assessing the fusion index of multinucleated myotubes. C2C12 myoblast proliferation was observed to increase significantly in response to Tenofovir (1 μM and 10 μM). In HSk cells however, proliferation was observed to decrease significantly in response to Tenofovir (1 μM). Zidovudine had no consistent effect on C2C12 proliferation at any dose tested, but caused a decrease in HSk myoblast proliferation (0.01 μM and 0.1 μM); however this was statistically non-significant. A small dose-dependent increase in C2C12 and HSk cell number, although not significant, was seen in response to Ritonavir. Wound closure results revealed both dose-dependent and time-dependent effects of Tenofovir and Zidovudine on human myoblast migration, with significant decreases in the rate of wound closure (4-7 hours) noted at 0.1 μM and 0.01 μM doses respectively. Zidovudine had no significant effect on migration while Ritonavir (0.01 μM) was observed to significantly increase percentage wound closure of human myoblasts, suggesting an increased ability to migrate during wound repair. Differentiation results indicated a decrease in myoblast fusion in response to all three ARVs. However only Ritonavir was shown to negatively affect myosin heavy chain expression. Further research into the exact mechanism of decreased fusion is required. To our knowledge, this study is the first to suggest that selected ARVs may significantly influence myoblast regeneration capabilities by modulating myoblast proliferation, migration, differentiation and fusion, and thereby decrease their myogenic capability. Extended human myoblast studies on differentiation could confirm this hypothesis. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.

Poster / Soc 397a / 2017 Poverty in Tucson Field Workshop

Virtual Reality är ett media med gamla rötter, men samtidigt en ny teknologi för allmänheten. Ett av problemen med VR är att det kan frammana visst obehag då det brukas, så kallad simulatorsjuka (Kennedy m.fl., 1993), vilket forskare studerar i syftet att förstå hur det undviks. I denna undersökning har en artefakt tagits fram i form av en spelprototyp, av slaget 2,5D-side-scrollingspel till VR, och använts för att studera uppkomsten av simulatorsjuka. Artefakten använder en head-mounted display för att uppnå VR. Tre testpersoner deltog i undersökningen, och för att mäta symptomen användes ett beprövat frågeformulär samt kvalitativa intervjuer. Data visar på att en tidigare hypotes om intryckskonflikt (Kolasinski, 1995, s.7) är inkorrekt, samt att konventionella orienteringsmekaniker har vissa fördelar. För framtida studier bör simulatorsjuka undersökas från fler vinklar och/eller med ett större urval av testpersoner.

Non-volatile memories (NVM) including flash memories and resistive memories have attracted significant interest as data storage media. Flash memories are widely employed in mobile devices and solid-state drives (SSD). Resistive memories are promising as storage class memory and embedded memory applications. Data reliability is the fundamental requirement of NVM as data storage media. However, modern nano-scale NVM suffers from challenges of inter-cell interference (ICI), charge leakage, and write endurance, which threaten the reliability of stored data. In order to cope with these adverse effects, advanced coding techniques including soft decision decoding have been investigated actively. However, current coding techniques do not capture the physical properties of NVM well, so the improvement of data reliability is limited. Although soft decision decoding improves the data reliability by using soft decision values, it degrades read speed performance due to multiple read operations needed to obtain soft decision values. In this dissertation, we explore coding schemes that use side information corresponding to the physical phenomena to improve the data reliability significantly. The side information is obtained before writing data into memory and incorporated during the encoding stage. Hence, the proposed coding schemes maintain the read speed whereas the write speed performance would be degraded. It is a big advantage from the perspective of speed performance since the read speed is more critical than the write speed in many memory applications. First, this dissertation investigates the coding techniques for memory with stuckat defects. The idea of coding techniques for memory with stuck-at defects is employed to handle critical problems of flash memories and resistive memories. For 2D planar flash memories, we propose a coding scheme that combats the ICI, which is a primary challenge of 2D planar flash memories. Also, we propose a coding scheme that reduces the effect of fast detrapping, a degradation factor in 3D vertical flash memories. Finally, we investigate the coding techniques that improve write endurance and power consumption of resistive memories.

Doxorubicin is one of the most potent anticancer drugs used in the treatment of wide spectrum of neoplastic diseases including breast, thyroid, colon and liver cancer. However, doxorubicin use is associated with undesirable side effects including cardiomyopathy and congestive heart failure. In the present study we have established that treatment of rat cardiac myoblasts (H9c2 cells) with doxorubicin resulted in H9c2 cell injury in a dose and time dependent manner with almost 50% cell death obtained at 5 μM of doxorubicin treatment for 24 hours. We have selected about 50% cell injury as optimum doxorubicin-induced cell injury because once this threshold is reached, cells became irreversibly injured and could not respond to protective treatment. Another potent antineoplastic drug cyclophosphamide had no cardiotoxic effects on H9c2 cells even at 35 μM concentration and up to 72 hours of treatment. Pretreatment of H9c2 cells for 24 hours with dexamethasone, cortisol, corticosterone or progesterone, significantly protect H9c2 myoblasts against subsequent 5 μM doxorubicin treatment for 24 hours in a concentration dependent manner with maximum protection obtained at 100 nM dexamethasone, 100 nM progesterone, 500 nM cortisol and 500 nM corticosterone. However, testosterone or dehydroepiandrosterone had no protective effects even at 10 μM concentration. It is concluded that both glucocorticoids and progesterone protect H9c2 cells against doxorubicin-induced cell injury.

Problem: There are a significant proportion of patients taking acetylcholinesterase inhibitors (ChEi) for cognitive dysfunction also taking medications with anticholinergic (ACh) properties that may counteract their effects. As the number of ACh medications, burden, increases so does the likelihood of an adverse outcome.Background: ACh medications are frequently used in the elderly population (Carnahan 2004) even those with dementia or AD (Roe et al., 2002; Giron et al., 2001; Altavela 2003; Gill et al., 2005; Kogut et al., 2005). Methods: Hospitalized patients > 65 years of age with dementia (AD, other dementias, or with inferred dementia based on ChEi or NMDA antagonist medication use) were studied using UHC clinical database. This document was created in Microsoft Word 2000. Results: Dementia patients on ChEi therapy were more likely to receive an ACh (chi-square 70.1, df=l, pConclusion: A person's age and mental health status along with their current drug regimen, such as ChEi therapy, need to be closely and carefully considered before deciding to use unnecessary ACh drugs in this population which can have detrimental effects.

Ketamine has shown promise as a novel treatment for depression and as a means to investigate the biology of depression. The drug effectively and rapidly treats depressed patients with the effects lasting approximately 1 week. However, concerns about ketamine’s efficacy do exist because of the inadequacy of blinding procedures used in existing trials. A dose of 0.5 mg/kg has been found to be most effective. Prolonged ketamine infusions have not extended the antidepressant effect beyond the timeframe of a regular infusion. Repeat infusions may be successful in extending ketamine’s effect, but definite conclusions cannot yet be made in this regard. Combination treatment with escitalopram and cognitive behavioral therapy (CBT) hold promise, as does the development of an intranasal formulation. Ketamine has shown additional efficacy as an acute anti-suicide treatment. Side effects from a single administration usually fade within a few hours and commonly include dissociation, elevations of blood pressure, nausea, and anxiety. Less data is available on the side effects caused by repeated ketamine infusions. Concerns exist regarding genitourinary, hepatic, and cognitive side effects after repeated infusions, as well as a risk of addiction. Research on ketamine’s mechanism of action has focused on the glutamate system in the brain. Ketamine may act by inhibiting release of γ–aminobutyric acid (GABA) from interneurons, activating intrasynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), increasing mammalian target of rapamycin complex 1 (mTORC1) and extracellular signal-regulated kinase (ERK) signaling, enhancing brain-derived neurotrophic factor (BDNF) production, inhibiting glycogen synthase kinase 3 (GSK3), blocking extrasynaptic N-Methyl-D-aspartate receptors (NMDARs), and promoting synaptogenesis and neuroplasticity. The two existing ketamine stereoisomers, (R)- versus (S)-ketamine, have different actions and potentially different efficacies and side effect profiles. Ketamine also produces regional changes in brain activity and connectivity. These include decreased burst firing in the lateral habenula (LHb), increased activity in the prefrontal cortex (PFC) and subgenual anterior cingulate cortex (ACC), and alterations in the amygdala’s response to angry and happy faces. Ketamine has the potential to be developed into a novel and useful clinical tool in the treatment of depression and to advance the understanding of the biology of depression.

Student Number : 9803192Y - MSc(Eng) Dissertation - School of Mechanical, Industrial and Aeronautical Engineering - Faculty of Engineering and the Built Environment / A computational °uid dynamics (CFD) study was carried out to improve the aero- dynamic performance of an agile high angle of attack missile. The normal force generated by the missile strakes had to be increased at the low angles of attack and the large side forces, experienced at high angles of attack due to the formation of steady asymmetric vortices had to be eliminated using strakelets on the missile nose. The ¯rst objective was achieved by increasing the missile strake span from 0:06D to 0:13D. The larger strake span increased the e®ective diameter of the missile body and prevented °ow reattachment to the body, a problem that was experienced when the strake span was 0:06D. Due to °ow separating further away from the body, strong vortices formed on the missile strakes, resulting in an increase in the normal force generated by the missile strakes at low angles of attack. The second objective was two-fold. Prior to analysing the e®ect of the strakelets on a steady asymmetric °ow¯eld, the steady asymmetric °ow¯eld had to ¯rst be created. This was achieved by placing a permanent, geometric perturbation on the missile nose. The size of the perturbation used in the study, which was determined by an iterative process, did not force °ow separation at low angles of attack and resulted in a steady asym- metric °ow¯eld that was representative of that on a blunt-ogive body. The e®ect of changing the span of the strakelets and the axial position of the strakelets were then investigated. It was found that the strakelets with a span of 0:09D, placed 1D from the nose tip eliminated the side forces by forcing vortex symmetry. Increasing or decreasing the span of the strakelet, positioned 1D from the nose tip or placing the strakelets with a span of 0:09D closer or further away from the nose tip did not eliminate the steady vortex asymmetry.