6,582 research outputs found
Wellesly Sh. W. to Mr. James Meredith (2 October 1962)
No full textSigned by Wellesly Sh. W.https://egrove.olemiss.edu/mercorr_pro/1531/thumbnail.jp
``ANOMALOUS'' RO-VIBRATIONAL INTENSITIES IN THE BANDS OF
No full text J.B. Burkholder, P.D. Hammer, C.J. Howard, A.G. Maki, G. Thompson, and C. Chackerian, Jr., J. Mol. Spectrosc. 124, 137 (1987). C. Chackerian, Jr., G. Guelachvili, A. Lopez-Pineiro. and R.H. Tipping, J. Chem. Phys. 90. 641 (1989). D.D. Nelson, Jr., A. Schiffman, D.J. Nesbitt and J.D. Yaron, J. Chem. Phys. (to be published).Author Institution: Laboratoire d'Infrarouge, Universite de Paris-Sud.; Laboratoire d'Infrarouge, NASA-Ames Research CenterRelative line Intensities of p- and r- branch transitions of diatomic radical molecules (ClO, NH, OH) have recently1-3 been used along with the theory of the Herman-Wallis effect to obtain estimates of electric dipole vibrational transition moments. Of the first and second row diatomic hydrides, ab initio calculations predict SH to exhibit the largest H.W. effect. Indeed, our spectra confirm a very large effect, and we present here an attempt at a quantitative analysis of the Herman-Wallis intensity perturbation in SH
An exploratory study on the Somali immigrant's involvement in the informal economy of Nelson Mandela Bay
No full textThe informal economy in South Africa and other parts of the continent is a safe haven for many who are unable to find jobs in the formal sector of the economy. In the case of South Africa, it is not only the nationals of the country who are striving to survive and generate their income from this sector. Since 1994, the country has experienced a huge influx of immigrants from other parts of the continent some escaping from dire living conditions in their home countries and looking for better life opportunities while many others were forced to migrate from their own countries as a result of political unrest and lack of stability and security. Among these later example is the Somali community who are the subject matter of this study. Many of these mainly African immigrants including Somalis got involved themselves in the informal sector of the South Africa. This has increased the competition in this sector and caused clashes between South Africans and immigrants who were also involved in the sector. This study examines the involvement of the Somali immigrants in South Africa’s informal sector. The study is exploratory in nature and tried to find the surrounding factors that impacted on the involvement of Somalis in the informal economy of Motherwell. The study has found that Somalis who arrived in Motherwell are generally young unmarried men who were attracted to the area mainly because there were affordable business opportunities in the township. Somalis financed their businesses through various resources including their savings from working while working inside and outside South Africa and from the contributions by their families and friends. Despite facing high levels of crime where many Somalis were killed and their property looted, they are still determined to stay in the township. This can be shown by their high level of savings and their intention to invest in the township. Although this research does not aim to be comparative in nature, personal and business characteristics of Somalis as well as South Africans who are also involved in the sector vii were compared. Because of this comparison, it has became clear that though price is an important factor in the business competition between the two groups, it is not the only factor, neither the most important, that creates friction and the shift of loyalty of customers from one side to another. Quality of service, the number of the people working in the business, responsibility towards the area the business serves, the strictness or the leniency towards customers who want to buy but are short of money and many other factors created a friendly atmosphere between the businesses run by the Somalis and their customers. The study showed that some of the Somali as well South African business owners were of this view. Although the vast majority of the Somalis have a minimum level of education, they still contribute positively to the economy of the township and the greater Nelson Mandela Bay. This is done through renting business premises, paying both direct and indirect taxes and taking the business services to remote areas of Motherwell. The study suggests that there is a need to sooth the relationship between the two groups particularly between Somalis and South Africans who are involved in grocery businesses through meetings, seminars, and other get-together activities. This can be done by South African Police Service, Somali Association of South Africa in Korsten, community elders from both sides and other concerned government institutions as well as the academic institutions particularly Nelson Mandela Metropolitan University. The business skills of both groups need to be uplifted in order to maximise their profitability and contribution to the people in the are
Estudo do efeito neuroprotetor da mirtazapina e imipramina e sua relação com a expressão gênica de proteínas apoptóticas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em Neurociências.Neste estudo foram investigados a ação neuroprotetora dos antidepressivos mirtazapina e imipramina e os efeitos destes compostos sobre a expressão gênica de proteínas anti- e pró-apoptóticas em células de neuroblastoma humano (SH-5YSY). Mirtazapina e imipramina mostraram baixa citotoxicidade sobre neuroblastoma humano e nas concentrações de 1-10 ?M aumentaram a viabilidade celular. As células de neuroblastoma humano foram pré-tratadas com mirtazapina e imipramina e depois incubadas na presença de tapsigargina ou peróxido de hidrogênio (H2O2). O pré-tratamento com mirtazapina e imipramina protegeu as células de neuroblastoma da citotoxicidade induzida pelo peróxido de hidrogênio. As células foram incubadas com mirtazapina e imipramina e a expressão gênica (RNAm) das proteínas envolvidas na sobrevivência (Bcl-2) e na morte celular (Bax, Bad e p53) foram determinadas por transcrição reversa e reação em cadeia da polimerase quantititiva (qRT-PCR). A mirtazapina reduziu e a imipramina não afetou a expressão gênica da proteína Bcl-2. A expressão gênica das proteínas Bax e p53 foi bastante reduzida pela mirtazapina e imipramina. A mirtazapina e a imipramina (2 ?M) aumentaram a razão Bcl-2/Bax e Blc-2/p53, indicando um efeito positivo na sobrevivência celular. Os resultados sugerem que o efeito neuroprotetor da mirtazapina e da imipramina envolve a redução da expressão gênica das proteínas pró-apoptóticas Bax e p53.In this study we investigated the neuroprotective effect of mirtazapine and imipramine and how these compounds affect the gene expression of anti-apoptotic and pro-apoptotic proteins in human neuroblastoma cells SH-SY5Y. Mirtazapine and imipramine showed low cytotoxicity on neuroblastoma cells and at concentrations of 1-10 ìM they increased the cell viability. Human neuroblastoma cells were pre-treated with mirtazapine and imipramine and then incubated with thapsigargin or hydrogen peroxide (H2O2). The pre-treatment with mirtazapine and imipramine protected the cells against H2O2-induced cell death. Cells were incubated with mirtazapine and imipramine and gene expression (mRNA) was determined for anti-apoptotic (Bcl-2) and pro-apoptotic proteins (Bax, Bad and p53) through qRT-PCR. Mirtazapine reduced and imipramine did not affect the expression level of the anti-apoptotic protein Bcl-2. The expression of Bax and p53 were strongly reduced by mirtazapine and imipramine. Both antidepressants increased the expression ratio of Bcl-2/Bax and Bcl-2/p53. These data suggest that the neuroprotective effect of mirtazapine and imipramine might be due the downregulation of pro-apoptotic Bax and p53 expression
SMA-SH: Modified styrene maleic acid copolymer for functionalization of lipid nanodiscs
No full textChallenges in purification and subsequent functionalization of membrane proteins often complicate their biochemical and biophysical characterization. Purification of membrane proteins generally involves replacing the lipids surrounding the protein with detergent molecules, which can affect protein structure and function. Recently, it was shown that styrene–maleic acid copolymers (SMA) can dissolve integral membrane proteins from biological membranes into nanosized discs. Within these nanoparticles, proteins are embedded in a patch of their native lipid bilayer that is stabilized in solution by the amphipathic polymer that wraps the disc like a bracelet. This approach for detergent-free purification of membrane proteins has the potential to greatly simplify purification but does not facilitate conjugation of functional compounds to the membrane proteins. Often, such functionalization involves laborious preparation of protein variants and optimization of labeling procedures to ensure only minimal perturbation of the protein. Here, we present a strategy that circumvents several of these complications through modifying SMA by grafting the polymer with cysteamine. The reaction results in SMA that has solvent-exposed sulfhydrils (SMA-SH) and allows tuning of the coverage with SH groups. Size exclusion chromatography, dynamic light scattering, and transmission electron microscopy demonstrate that SMA-SH dissolves lipid bilayer membranes into lipid nanodiscs, just like SMA. In addition, we demonstrate that, just like SMA, SMA-SH solubilizes proteoliposomes into protein-loaded nanodiscs. We covalently modify SMA-SH-lipid nanodiscs using thiol-reactive derivatives of Alexa Fluor 488 and biotin. Thus, SMA-SH promises to simultaneously tackle challenges in purification and functionalization of membrane proteins.BN/Marie-Eve Aubin-Tam LabBN/Andreas Engel La
Omega-3 fatty acid eicospentaenoic acid attenuates MPP+-induced neurodegeneration in fully differentiated human SH- SY5Y and primary mesencephalic cells
No full textEicosapentaenoic acid ( EPA), a neuroactive omega-3 fatty acid, has been demonstrated to exert neuroprotective effects in experimental models of Parkinson's disease ( PD), but the cellular mechanisms of protection are unknown. Here, we studied the effects of EPA in fully differentiated human SH-SY5Y cells and primary mesencephalic neurons treated with MPP+. In both in-vitro models of PD, EPA attenuated an MPP+-induced reduction in cell viability. EPA also prevented the presence of electron-dense cytoplasmic inclusions in SH-SY5Y cells. Then, possible mechanisms of the neuroprotection were studied. In primary neurons, EPA attenuated an MPP+-induced increase in Tyrosine-related kinase B (TrkB) receptors. In SH-SY5Y cells, EPA down-regulated reactive oxygen species and nitric oxide. This antioxidant effect of EPA may have been mediated by its inhibition of neuronal NADPH oxidase and cyclo-oxygenase-2 ( COX-2), as MPP+ increased the expression of these enzymes. Furthermore, EPA prevented an increase in cytosolic phospholipase A2 ( cPLA2), an enzyme linked with COX-2 in the potentially pro-inflammatory arachidonic acid cascade. Lastly, EPA attenuated an increase in the bax:bcl-2 ratio, and cytochrome c release. However, EPA did not prevent mitochondrial enlargement or a decrease in mitochondrial membrane potential. This study demonstrated cellular mechanisms by which EPA provided neuroprotective effects in experimental P
Effects of Na Neutralization Level on the SH Behaviour after Ballistic Tests of EMAA Based Ionomers
No full textEthylene-co-methacrylic acid (EMAA) based ionomers have thermo-mechanical properties strongly dependent on neutralization level of acid groups. Research revealed also how these materials are able to heal after ballistic impacts. In order to better understand the role of neutralization level on the Self-Healing (SH) behaviour, mechanical and ballistic tests on EMAA copolymers, neutralized with different amount of Na ions, were performed in different experimental conditions. The SH capability was studied by shooting bullets at low velocity (180 m/s) and mid velocity (400 m/s); different testing conditions such as sample thickness and bullet diameter were examined. In all impact tests, spherical projectiles were used. These experiments allowed to define a critical ratio between sample thickness and bullet diameter below which the SH behaviour does not appear. After ballistic damage, the healing efficiency was evaluated by applying a pressure difference through tested samples. Subsequently, morphology analysis of the impacted areas was made observing all tested samples by Scanning Electron Microscope (SEM). These analysis revealed different characteristic features in the damaged zones of tested polymers impacted at different projectile speed. Obtained results show how the Na ions content influences the SH capability; in particular the EMAA copolymer with the highest Na neutralization level does not show a complete hole closure after low velocity impact test. Conversely, increasing projectile speed, all the polymers exhibit nearly the same SH behaviour
Low airspeed systems for the naval SH-60 Seahawk aircraft
No full textPitot-static systems have long been used to measure helicopter airspeed. The Pitot-static system is inaccurate at low airspeeds (below 40 knots) due to the limited sensitivity of the sensor and interference of rotor down wash. Additionally, the Pitot-static system only measures unidirectional airspeed and unlike its fixed wing counterparts the helicopter is not limited to flight in one direction. With the changing roles of the US Navy Seahawk it is imperative that the pilot and aircrew have all the information necessary to safely complete the mission and prolong the life of the aircraft and dynamic components. With the addition of a dipping sonar to the remanufactured SH-60B aircraft (designated SH- 60R) and the conduct of combat search and rescue mission in the Navy\u27s Seahawks the aircraft will spend more time in a hover and will be flown more aggressively than in the past. This thesis examiness the advantages of incorporating a low airspeed system into the modem helicopter, in particular the SH-60 Seahawk. The author examines the low airspeed sensors and systems currently available and gives a brief description of each system\u27s operation. The author examines the challenges of installing a low airspeed sensor onto the SH-60 Seahawk. The author has determined that either a laser velocimeter or an analytical neural network system would be the best approach for a low airspeed system for the SH-60 Seahawk. The author recommends a combined approach be taken to develop both the laser velocimeter and analytical neural network, and incorporate the best system after further flight testing
ω-3 fatty acid eicosapentaenoic acid attenuates MPP+-induced neurodegeneration in fully differentiated human SH-SY5Y and primary mesencephalic cells
No full textEicosapentaenoic acid (EPA), a neuroactive omega-3 fatty acid, has been demonstrated to exert neuroprotective effects in experimental models of Parkinson's disease (PD), but the cellular mechanisms of protection are unknown. Here, we studied the effects of EPA in fully differentiated human SH-SY5Y cells and primary mesencephalic neurons treated with MPP(+) . In both in-vitro models of PD, EPA attenuated an MPP(+) -induced reduction in cell viability. EPA also prevented the presence of electron-dense cytoplasmic inclusions in SH-SY5Y cells. Then, possible mechanisms of the neuroprotection were studied. In primary neurons, EPA attenuated an MPP(+) -induced increase in Tyrosine-related kinase B (TrkB) receptors. In SH-SY5Y cells, EPA down-regulated reactive oxygen species and nitric oxide. This antioxidant effect of EPA may have been mediated by its inhibition of neuronal NADPH oxidase and cyclo-oxygenase-2 (COX-2), as MPP(+) increased the expression of these enzymes. Furthermore, EPA prevented an increase in cytosolic phospholipase A2 (cPLA2), an enzyme linked with COX-2 in the potentially pro-inflammatory arachidonic acid cascade. Lastly, EPA attenuated an increase in the bax:bcl-2 ratio, and cytochrome c release. However, EPA did not prevent mitochondrial enlargement or a decrease in mitochondrial membrane potential. This study demonstrated cellular mechanisms by which EPA provided neuroprotective effects in experimental PD.
(© 2012 The Authors Journal of Neurochemistry © 2012 International Society for Neurochemistry.
ω-3 fatty acid eicosapentaenoic acid attenuates MPP+-induced neurodegeneration in fully differentiated human SH-SY5Y and primary mesencephalic cells.
No full textEicosapentaenoic acid (EPA), a neuroactive omega-3 fatty acid, has been demonstrated to exert neuroprotective effects in experimental models of Parkinson's disease (PD), but the cellular mechanisms of protection are unknown. Here, we studied the effects of EPA in fully differentiated human SH-SY5Y cells and primary mesencephalic neurons treated with MPP(+) . In both in-vitro models of PD, EPA attenuated an MPP(+) -induced reduction in cell viability. EPA also prevented the presence of electron-dense cytoplasmic inclusions in SH-SY5Y cells. Then, possible mechanisms of the neuroprotection were studied. In primary neurons, EPA attenuated an MPP(+) -induced increase in Tyrosine-related kinase B (TrkB) receptors. In SH-SY5Y cells, EPA down-regulated reactive oxygen species and nitric oxide. This antioxidant effect of EPA may have been mediated by its inhibition of neuronal NADPH oxidase and cyclo-oxygenase-2 (COX-2), as MPP(+) increased the expression of these enzymes. Furthermore, EPA prevented an increase in cytosolic phospholipase A2 (cPLA2), an enzyme linked with COX-2 in the potentially pro-inflammatory arachidonic acid cascade. Lastly, EPA attenuated an increase in the bax:bcl-2 ratio, and cytochrome c release. However, EPA did not prevent mitochondrial enlargement or a decrease in mitochondrial membrane potential. This study demonstrated cellular mechanisms by which EPA provided neuroprotective effects in experimental PD
- …
