281 research outputs found

    Synthesis and Characterization of Novel Electrode Material for Lithium-Sulfur Batteries

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    Lithium-sulfur (Li-S) batteries are becoming increasingly attractive as one of the most promising advanced secondary batteries with overwhelming advantages of high theoretical capacity (1675 mAh/g) and high energy density (2600 VS. 420 W h/kg of traditional Li-ion batteries). Sulfur is one of the most abundant elements on earth and is an underutilized byproduct from the oil and gas industries. Additionally, in comparison to Li-ion batteries, Li-S batteries have improved safety and lower cost. They are also more environmentally friendly. However, the predominant challenge with lithium-sulfur batteries is capacity drop and low cycle life during usage of the sulfur-based electrode. This project aims to solve this problem by careful design of carbon based nanomaterials to physically and/or chemically confine the sulfur component. Developing the sulfur/carbon nanocomposite will be conducted using well-studied synthesis processes. Characterization of the electrodes will be conducted through analytical techniques via scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), x-ray diffraction (XRD), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). Electrochemical evaluation of assembled split cell will consist of cyclability and rate capability testing using the electrochemical testing station. The expected outcome is to achieve high performance of Li-S batteries with long cycle life and maintaining high specific capacity, a goal for emerging advanced energy storage technology, portable electronics, and grid-scale energy station

    Identification and Characterization of the Expression Profile of Oligodendrocyte-Derived and Associated Proteins via Unilateral X-Irradation of the Rat Optic Nerve

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    Recent studies examining cell-cell interactions during CNS development and following disease or trauma have highlighted our limited understanding of the in vivo functions of the myelinating cell of the CNS, the oligodendrocyte. With this in mind, our laboratory has developed techniques by which a profile of proteins derived from or regulated by oligodendrocytes can be elucidated. Specifically, we have demonstrated that oligodendrocytes can be selectively eliminated from one optic nerve of a rat by treating the animal with a unilateral exposure of X-irradiation at the time of birth. Consequently, this approach allowed us to experimentally create, within the same animal, one optic nerve devoid of oligodendrocytes and their progenitors (the X- irradiated side) and one optic nerve containing the normal oligodendrocyte population (the untreated side). Using this experimental animal model we hypothesized that uncharacterized proteins, derived from and regulated by oligodendrocytes, which are crucial for CNS development can be identified. Specifically, by comparing protein profiles found within the normal myelinating optic nerve versus the X-irradiated optic nerve, where oligodendrocytes are absent, potential oligodendrocyte-derived proteins can be quickly identified. Further verification that these proteins are indeed related to oligodendrocytes and/or the processes of myelination can be obtained by their reappearance in the 2-D gel protein profile of P28 X-irradiated nerves that, as we have shown previously, undergo a delayed myelination. We then employed mass spectrometric analysis to determine the identities of oligodendrocyte derivedregulated proteins. In this thesis, I will begin by describing our current knowledge of the proteins expressed by oligodendrocytes and their role(s) in oligodendrocyte function. This will be followed by a detailed description of the experimental model system we utilized in an attempt to elucidate the complete repertoire of oligodendrocyte-regulated proteins. We will then describe the results generated fiom our methodology and discuss the implications of our findings in relation to the functional cooperation between oligodendrocytes and other cells of the developing central nervous system. The results generated fiom this project should lead to a clearer understanding of the role of oligodendrocytes and\u27of the array of proteins whose expression patterns are associated with these cells during CNS development

    Scott Calhoun, U2 and the Religious Impulse: Take Me Higher

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    Does the world need another edited collection on the Irish rock band, U2? Maybe not. After all, the band have gained enough commercial success and garnered enough attention already. They have received so much visibility that it has gone to their collective rock star heads. Bono, the band’s lead singer and, arguably, the biggest ego of the group, has used (and perhaps abused) his cultural capital to mingle with those with political capital (not to mention monetary capital) to try to affect cha..

    An hypothesis on crustacean pigmentation metabolism:L-carnitine and nuclear hormone receptors as limiting factors

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    Astaxanthin (Axn) is the primary pigment molecule in crustaceans associated with quality, health and growth traits, leading to increased marketing value. Axn can be contained within the protein complex crustacyanin (CRCN) to produce an array of different shell colours, or esterified with fatty acids (FA) for storage but also contributing additional red colouration. l-Carnitine (LC) has a major role in FA oxidation and mitochondrial function optimization, which could influence the proportion of Axn complexed with FA or CRCN. Peroxisome proliferator activated receptors (PPARs) have important roles in FA and Axn uptake, and stored lipid oxidation affecting Axn homeostasis and storage in lipid bodies. Whether Axn could increase PPAR signalling and carnitine palmitoyl transferase activity, leading to induction of lipid metabolism, is not known in crustaceans. Several FA have been shown to preferentially form FA Axn-esters, including saturated fatty acids (SFA) such as C16:0 and C18:0, mono-unsaturated fatty acids (MUFA) such as C16:1 and C18:1, and poly-unsaturated fatty acids (PUFA) such as C20:4, C20:5, and C20:6. We hypothesize that manipulating the dietary ratios and inclusion of LC, Axn, and specific FA may be able to further improve pigment utilization, lipid metabolism, health, and growth in crustaceans.</p

    ALDH Activity Correlates with Metastatic Potential in Primary Sarcomas of Bone.

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    Osteosarcoma (OS), chondrosarcoma (CSA), and Ewings sarcoma (ES) are the most common primary malignancies of bone, and are rare diseases. As with all sarcomas, the prognosis of these diseases ultimately depends on the presence of metastatic disease. Survival is therefore closely linked with the biology and metastatic potential of a particular bone tumor's cells. Here we describe a significant correlation of aldehyde dehydrogenase (ALDH) activity and the presence/absence of distant metastases in ten consecutive cases of human bone sarcomas. Additionally, cultured human CSA cells, which are historically chemo- and radio-resistant, may be sensitive to the ALDH inhibitor, disulfiram. While it is premature to draw broad conclusions from such a small series, the importance of ALDH activity and inhibition in the metastatic potential of primary bone sarcomas should be investigated further

    Outcomes of endovascular treatment of ruptured abdominal aortic aneurysms

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    IntroductionThe successful application of endovascular techniques for the elective repair of abdominal aortic aneurysms (AAAs) has stimulated a strong interest in their possible use in dealing with a long-standing surgical challenge: the ruptured abdominal aortic aneurysm (RAAA). The use of a conventional open procedure to repair ruptured aneurysms is associated with a high operative mortality of 45% to 50%. In this study, we evaluated the current frequency of endovascular repair of RAAAs in four large states and the impact of this technique on patient outcome.MethodsWe examined discharge data sets from 2000 through 2003 from the four states of California, Florida, New Jersey, and New York, whose combined population represents almost a third of the United States population. Proportions and trends were analyzed by χ2 analysis and continuous variables by the Student’s t test.ResultsWe found that since the year 2000, endovascular repair has begun to emerge as a viable treatment option for RAAAs, accounting for the repair of 6.2% of cases in 2003. During the same period, the use of open procedures for RAAAs declined. The overall mortality rate for the 4-year period was significantly lower for endovascular vs open repair (39.3% vs. 47.7%, P = .005). Moreover, compared with open repair, endovascular repair resulted in a significantly lower rate of pulmonary, renal, and bleeding complications. Survival after endovascular repair correlated with hospital experience, as assessed by the overall volume of elective and nonelective endovascular procedures. For endovascular repairs, mortality ranged from 45.9% for small volume hospitals to 26% for large volume hospitals (P = .0011). Volume was also a determinant of mortality for open repairs, albeit to a much lesser extent (51.5% for small volume hospitals, 44.3% for large volume hospitals; P < .0001).ConclusionWe observed a benefit to using endovascular procedures for RAAAs in institutions with significant endovascular experience; however, the analysis of administrative data cannot rule out selection bias as an explanation of better outcomes. These data strongly endorse the need for prospective studies to clarify to what extent the improved survival in RAAA patients is to be attributed to the endovascular approach rather than the selection of low-risk patients

    Open Versus Laparoscopic Adrenalectomy for Adrenocortical Carcinoma: A Meta-analysis of Surgical and Oncological Outcomes

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    PURPOSE: This study was designed to determine the role of laparoscopic adrenalectomy (LA) in the surgical management of adrenocortical carcinoma (ACC). METHODS: A systematic literature review was performed on January 2, 2015 using PubMed. Article selection proceeded according to PRISMA criteria. Studies comparing open adrenalectomy (OA) to LA for ACC and including at least 10 cases per each surgical approach were included. Odds ratio (OR) was used for all binary variables, and weight mean difference (WMD) was used for the continuous parameters. Pooled estimates were calculated with the fixed-effect model, if no significant heterogeneity was identified; alternatively, the random-effect model was used when significant heterogeneity was detected. Main demographics, surgical outcomes, and oncological outcomes were analyzed. RESULTS: Nine studies published between 2010 and 2014 were deemed eligible and included in the analysis, all of them being retrospective case-control studies. Overall, they included 240 LA and 557 OA cases. Tumors treated with laparoscopy were significantly smaller in size (WMD -3.41 cm; confidence interval [CI] -4.91, -1.91; p &lt; 0.001), and a higher proportion of them (80.8 %) more at a localized (I-II) stage compared with open surgery (67.7 %) (odds ratio [OR] 2.8; CI 1.8, 4.2; p &lt; 0.001). Hospitalization time was in favor of laparoscopy, with a WMD of -2.5 days (CI -3.3, -1.7; p &lt; 0.001). There was no difference in the overall recurrence rate between LA and OA (relative risk [RR] 1.09; CI 0.83, 1.43; p = 0.53), whereas development of peritoneal carcinomatosis was higher for LA (RR 2.39; CI 1.41, 4.04; p = 0.001). No difference could be found for time to recurrence (WMD -8.2 months; CI -18.2, 1.7; p = 0.11), as well as for cancer specific mortality (OR 0.68; CI 0.44, 1.05; p = 0.08). CONCLUSIONS: OA should still be considered the standard surgical management of ACC. LA can offer a shorter hospital stay and possibly a faster recovery. Therefore, this minimally invasive approach can certainly play a role in this setting, but it should be only offered in carefully selected cases to avoid jeopardizing the oncological outcome.PURPOSE: This study was designed to determine the role of laparoscopic adrenalectomy (LA) in the surgical management of adrenocortical carcinoma (ACC). METHODS: A systematic literature review was performed on January 2, 2015 using PubMed. Article selection proceeded according to PRISMA criteria. Studies comparing open adrenalectomy (OA) to LA for ACC and including at least 10 cases per each surgical approach were included. Odds ratio (OR) was used for all binary variables, and weight mean difference (WMD) was used for the continuous parameters. Pooled estimates were calculated with the fixed-effect model, if no significant heterogeneity was identified; alternatively, the random-effect model was used when significant heterogeneity was detected. Main demographics, surgical outcomes, and oncological outcomes were analyzed. RESULTS: Nine studies published between 2010 and 2014 were deemed eligible and included in the analysis, all of them being retrospective case-control studies. Overall, they included 240 LA and 557 OA cases. Tumors treated with laparoscopy were significantly smaller in size (WMD -3.41 cm; confidence interval [CI] -4.91, -1.91; p &lt; 0.001), and a higher proportion of them (80.8 %) more at a localized (I-II) stage compared with open surgery (67.7 %) (odds ratio [OR] 2.8; CI 1.8, 4.2; p &lt; 0.001). Hospitalization time was in favor of laparoscopy, with a WMD of -2.5 days (CI -3.3, -1.7; p &lt; 0.001). There was no difference in the overall recurrence rate between LA and OA (relative risk [RR] 1.09; CI 0.83, 1.43; p = 0.53), whereas development of peritoneal carcinomatosis was higher for LA (RR 2.39; CI 1.41, 4.04; p = 0.001). No difference could be found for time to recurrence (WMD -8.2 months; CI -18.2, 1.7; p = 0.11), as well as for cancer specific mortality (OR 0.68; CI 0.44, 1.05; p = 0.08). CONCLUSIONS: OA should still be considered the standard surgical management of ACC. LA can offer a shorter hospital stay and possibly a faster recovery. Therefore, this minimally invasive approach can certainly play a role in this setting, but it should be only offered in carefully selected cases to avoid jeopardizing the oncological outcome

    Sugar concentration influences decision making in<em> Apis mellifera</em> L. workers during early-stage honey storage behaviour

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    Decision making in honeybees is based on in- formation which is acquired and processed in order to make choices between two or more al- ternatives. These choices lead to the expression of optimal behaviour strategies such as floral constancy. Optimal foraging strategies such as floral constancy improve a colony’s chances of survival, however to our knowledge, there has been no research on decision making based on optimal storage strategies. Here we show, using diagnostic radioentomology, that decision mak- ing in storer bees is influenced by nectar sugar concentrations and that, within 48 hours of col- lection, honeybees workers store carbohydrates in groups of cells with similar sugar concentra- tions in a nonrandom way. This behaviour, as evidenced by patchy spatial cell distributions, would help to hasten the ripening process by reducing the distance between cells of similar sugar concentrations. Thus, colonies which ex- hibit optimal storage strategies such as these would have an evolutionary advantage and im- prove colony survival expectations over less efficient colonies and it should be plausible to select colonies that exhibit these preferred traits
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