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Theoretical Study of Electron Transfer in Organic Solar Cells
No full textOrganic solar devices can provide a cheaper alternative to the current silicon-based solar cell devices. The main disadvantage of organic photovoltaic is their low efficiency. Therefore there is a great need to better understand the mechanism of electron transfer in order to improve the efficiency of these devices. The main goal in my dissertation is to find a more accurate measure of electron transfer in these devices. I have been using theoretical methods to study electron transfer in fullerene derivatives, a common component of organic solar devices. One such method that we have investigated is time-dependent split (TD-Split) to study A to B electron transfer by a TD evaluation of the lowest energy transition from the ground state of the combined (AB)- system. Another method that we have developed is the time-dependent ZINDO method (TD-ZINDO) to study absorption. ZINDO is a useful theoretical tool for systems of interest due to its capacity to handle large systems within reasonable times. We were able to perform explicit time calculations with a minimal basis set. The results were then compared with higher order DFT and TDDFT results. We also used a DFT based method to calculate the charge transfer between very large solvated organic dimers like fullerenes from isolated dimer calculations. In this method, a delocalized bias is applied directly to the Fock matrix of the dimer until the extra electron is balanced between the two molecules in the dimers. Then the transfer rate can be calculated using Marcus theory. These theoretical methods differ in accuracy and speed. In my dissertation, I will present these different methods and compare them to each other and to experimental values
Electron transfer beyond the static picture: A TDDFT/TD-ZINDO study of a pentacene dimer
No full textWe use time-dependent density functional theory and time-dependent ZINDO (a semi-empirical method) to study transfer of an extra electron between a pair of pentacene molecules. A measure of the electronic transfer integral is computed in a dynamic picture via the vertical excitation energy from a delocalized anionic ground state. With increasing dimer separation, this dynamical measurement of charge transfer is shown to be significantly larger than the commonly used static approximation (i.e., LUMO+1-LUMO of the neutral dimer, or HOMO-LUMO of the charged dimer), up to an order of magnitude higher at 6 Å. These results offer a word of caution for calculations involving large separations, as in organic photovoltaics, where care must be taken when using a static picture to model charge transfer. © 2012 American Institute of Physics
Direct delocalization for calculating electron transfer in fullerenes
No full textABSTRACT A method is introduced for simple calculation of charge transfer between very large solvated organic dimers (fullerenes here) from isolated dimer calculations. The individual monomers in non-centrosymmetric dimers experience different chemical environments, so that the dimers do not necessarily represent bulk-like molecules. Therefore, we apply a delocalizing bias directly to the Fock matrix of the dimer system, and verify that this is almost as accurate as self-consistent solvation. Since large molecule like fullerenes have a plethora of excited states, the initially excited state orbitals are thermally populated, so that the rate is obtained as a thermal average over Marcus thermal transfers
Bilateral Asymptomatic Extracranial Carotid Artery Aneurysms
No full textAneurysms of the extracranial carotid arteries are rare and account for 0.4-1percent of all arterial aneurysms and about 4percent of all peripheral arterial aneurysms. Causes include atherosclerosis, fibromuscular dysplasia, trauma (penetrating and blunt cervical trauma and hyperextension of the neck), iatrogenic lesions, infection, congenital defects, and irradiation arteritis. Atherosclerosis is responsible for 46-70percent of all carotid artery aneurysms. The most frequent site of carotid artery aneurysms is the common carotid artery, particularly at its bifurcation and proximal internal carotid artery (ICA). The middle and distal portions of the ICA are the next most common sites. Aneurysms at the point of bifurcation are usually fusiform, whereas those located in the middle and distal portions of the ICA are usually saccular. This uncommon but interesting vascular disorder usually presents as a parapharyngeal pulsatile mass. It can be partially or completely thrombosed and thereby cause embolization or compression of neurovascular structures, with ruptures and ischemic events as other complications. Surgical treatment of extracranial carotid aneurysms is required in most cases, to avert disastrous consequences. Conservative management of extracranial ICA aneurysms has resulted in a mortality rate of nearly 71percent. Nonoperative treatment is generally indicated in young patients who have nonpenetrating traumatic and spontaneously dissecting aneurysms. However, when anticoagulation therapy fails or when persistent neurologic symptoms or progressive expansion of the aneurysm occurs, surgical repair is indicated.Alpagut U, 2005, ACTA CHIR BELG, V105, P407; BILAL B, 2007, ARCH TURK SOC CARDIO, V35, P246; Bouarhroum A, 2006, J VASC SURG, V43, P627, DOI 10.1016-j.jvs.2005.09.049; BOWERS J, 1991, GENDER SOC, V5, P125, DOI 10.1177-089124391005001009; Chuman H, 2002, J NEURO-OPHTHALMOL, V22, P75, DOI 10.1097-01.WNO.00000195665.92684.6A; Cooper A, 1836, GUYS HOSP REP, V1, P53; El-Sabrout R, 2000, J VASC SURG, V31, P702, DOI 10.1067-mva.2000.104101; Faggioli G, 1996, J VASC SURG, V23, P587, DOI 10.1016-S0741-5214(96)80037-1; Kawada Tadanori, 2002, Ann Thorac Cardiovasc Surg, V8, P183; KNIGHT GC, 1988, TEX HEART I J, V15, P91; LETTER DA, 1989, CAN J SURG, V32, P463; Mathews J, 2001, J LARYNGOL OTOL, V115, P663; May J, 1997, J VASC SURG, V26, P1055, DOI 10.1016-S0741-5214(97)70020-X; McCann R L, 1990, Ann Vasc Surg, V4, P411, DOI 10.1007-BF02000509; MCCOLLUM CH, 1979, AM J SURG, V137, P196, DOI 10.1016-0002-9610(79)90144-2; Moreau P, 1994, Ann Vasc Surg, V8, P409, DOI 10.1007-BF02133059; Nicholson M L, 1988, Eur J Vasc Surg, V2, P197, DOI 10.1016-S0950-821X(88)80076-8; Oderich GS, 2007, J VASC SURG, V46, P475, DOI 10.1016-j.jvs.2007.03.055; RITTENHO.EA, 1972, ARCH SURG-CHICAGO, V105, P786; Rosset E, 2000, J VASC SURG, V31, P713, DOI 10.1067-mva.2000.104102; Rosset E, 1994, Cardiovasc Surg, V2, P567; Rossi P, 1997, J CARDIOVASC SURG, V38, P27; SCHIEVINK WI, 1994, NEUROSURGERY, V35, P809; van Sambeek MRHM, 2000, J ENDOVASC THER, V7, P353, DOI 10.1583-1545-1550(2000)0070353:EROAEI2.0.CO;2; WELLING RE, 1983, SURGERY, V93, P319; Winslow N, 1926, ARCH SURG-CHICAGO, V13, P689; Zampella E J, 1988, Ala J Med Sci, V25, P67; ZWOLAK RM, 1984, J VASC SURG, V1, P415, DOI 10.1067-mva.1984.avs001041530
Análise da favela como objeto de consumo no século XXI: um olhar sobre o produto Favela Tour
No full textEste trabalho busca verificar e compreender um pouco mais sobre as favelas como destino turístico. Sendo inegável a presença da atividade turística nas comunidades carentes do Rio de Janeiro, recebendo milhares de turistas a cada mês, pretende-se aqui averiguar as características deste consumidor, como funciona a atividade e de que maneira ela interfere nas comunidades onde á desenvolvida. Para isto, procurasse analisar o turismo como promotor do desenvolvimento e o tour em favelas sob o
ponto de vista do produto turístico; aborda-se também características da demanda turística e do mercado atual. Adota-se ainda, como objeto de estudo, o empreendimento “Favela Tour”: empresa com experiência de quase 20 anos neste mercado e com reconhecimento internacional que realiza passeios em grupos em duas favelas da cidade do Rio de janeiro, Rocinha e Vila Canoas. Descreve-se o roteiro sob o olhar do autor que se coloca no lugar do consumidor e vivencia a experiência de conferir de perto as comunidades carentes. Por fim, verifica-se os resultados oriundos da aplicação de questionários aos clientes do Favela Tour, durante o mês de maio de 2010, com o objetivo de traçar o perfil destes turistas, e
relacionando-os com o referencial teóricoThis paper has as its main aim verifying and understanding a little bit more about favelas as a touristic destination. The presence of touristic activity in Rio de Janeiro’s poorer communities is undeniable; they are visited by thousands of tourists every month. The objective here is to check these consumers’ characteristics, to find out how this activity works and in what ways it interferes on the communities where it is developed. For this, the intention is to analyze tourism as promoter of this
development and the tours in favelas under a touristic product point of view. The characteristics of the touristic demand and from the current market are also dealt wit here. The object of study adopted is the Favela Tour, an internationally recognized company that has had almost twenty years of expertise in this market organizing tours for groups of tourists in two favelas from Rio de Janeiro, Rocinha and Vila Canoas. The itinerary is described by the author, who puts himself in the consumer’s shoes and experiences a close look into the needy communities. Finishing it up, the
results coming from the application of questionnaires on Favela Tour clients on May 2010 are analyzed having the objective of profiling these tourists and relating them to the theoretical referentia
Solitary hydatid cyst of the thigh: A challenging diagnosis
No full textA 53-year-old woman presented with an enlarging mass in the medial aspect of her right thigh. Magnetic resonance imaging suggested an intramuscular hydatid cyst. The cyst was surgically excised. Although muscular hydatidinosis is rare, its resemblance to soft tissue tumors warrants careful diagnosis since any invasive diagnostic measures may lead to fatal complications. © 2009, Mary Ann Liebert, Inc.Battelli G., 2002, Parassitologia (Rome), V44, P43; Bouree P, 2001, WORLD J SURG, V25, P4, DOI 10.1007-s002680020001; Comert RB, 2003, SKELETAL RADIOL, V32, P420, DOI 10.1007-s00256-003-0661-x; Dahniya MH, 2001, BRIT J RADIOL, V74, P283; Durakbasa M O, 2007, J Orthop Surg (Hong Kong), V15, P118; Eckert J, 2001, WHO OIE MANUAL ECHIN; Kocakusak A, 2004, ACTA CHIR BELG, V104, P471; Merkle EM, 1997, AM J ROENTGENOL, V168, P1531; Orhan Z, 2003, BMC MUSCULOSKEL DIS, V4, DOI 10.1186-1471-2474-4-25; Ozkoc G, 2003, ARCH ORTHOP TRAUM SU, V123, P314, DOI 10.1007-s00402-003-0512-1; Safioleas M, 2000, INT SURG, V85, P35822
Effect of Lysine, Vitamin B6, and Carnitine Supplementation on the Lipid Profile of Male Patients With Hypertriglyceridemia: A 12-Week, Open-Label, Randomized, Placebo-Controlled Trial
No full textBackground: Fat metabolism is known to be altered in hypertriglyceridemia. Fat oxidation requires carnitine, which can be obtained either from the diet (animal or dairy products) or through synthesis in the body using both lysine and vitamin B6. Objective: The goal of this study was to investigate the effect of lysine, vitamin B6, and carnitine supplementation on both glycemia and the lipid profiles, specifically triglyceride (TG) levels, in men with hypertriglyceridemia. Methods: This 12-week, randomized, placebo-controlled clinical trial was conducted at a Lebanese medical center. A total of 85 hypertriglyceridemic (TGandgt; 150 mg-dL) male patients were randomized to 1 of 5 groups and given supplements of lysine (1 g-d), vitamin B6 (50 mg-d), lysine (1 g-d) + vitamin B6 (50 mg-d), carnitine (1 g-d), or placebo for 12 weeks. The lipid profile (TG, total cholesterol, LDL-C, and HDL-C) and fasting plasma glucose levels were assessed at baseline and at 6 and 12 weeks. Results: Adults (~50 years) Lebanese males from a low socioeconomic status in Beirut were given the appropriate supplements. Vitamin B6 supplementation was associated with a significant reduction in total cholesterol and HDL-C of ~10percent. In addition, plasma TG was reduced by 36.6 mg-dL at 6 weeks, whereas levels in the placebo group increased by 18 mg-dL; this difference failed to reach statistical significance. No major changes in the lipid profile were observed in the lysine and carnitine groups or when lysine was added to vitamin B6. Conclusion: Vitamin B6 supplementation in these male patients with hypertriglyceridemia reduced plasma total cholesterol and HDL-C concentrations. © 2012 Elsevier HS Journals, Inc.Sibai Abla-Mehio, 2008, CVD Prevention and Control, V3, DOI 10.1016-j.precon.2007.06.002; BRADY PS, 1987, BIOCHEM J, V246, P641; BRATTSTROM L, 1990, SCAND J CLIN LAB INV, V50, P873, DOI 10.3109-00365519009104955; BROWNLEE M, 1984, DIABETES, V33, P532, DOI 10.2337-diabetes.33.6.532; Chen W, 1998, AM J CLIN NUTR, V67, P221; CHO YO, 1990, J NUTR, V120, P258; Derosa G, 2003, CLIN THER, V25, P1429, DOI 10.1016-S0149-2918(03)80130-3; DIONYSSIOUASTERIOU A, 1986, BIOCHEM MED METAB B, V36, P114, DOI 10.1016-0885-4505(86)90114-3; DUNN WA, 1982, J BIOL CHEM, V257, P7948; GODSLAND IF, 1990, NEW ENGL J MED, V323, P1375, DOI 10.1056-NEJM199011153232003; GONEN B, 1981, DIABETES, V30, P875, DOI 10.2337-diabetes.30.10.875; Gropper S. S., 2005, ADV NUTR HUMAN METAB; HAFFNER SM, 1993, J CLIN ENDOCR METAB, V77, P1610, DOI 10.1210-jc.77.6.1610; Harripersad R, 1997, INT J VITAM NUTR RES, V67, P95; Hatchcock JN, 2006, REGUL TOXICOL PARMAC, V46, P23; Iritani N, 1997, J NUTR, V127, P1077; Kalogeropoulou D, 2009, AM J CLIN NUTR, V90, P314, DOI 10.3945-ajcn.2008.27381; KHAN L, 1979, J NUTR, V109, P24; Krajcovicova-Kudlackova M, 2000, PHYSIOL RES, V49, P399; Obeid O, 2008, ECOL FOOD NUTR, V47, P298, DOI 10.1080-03670240701821337; Peeke PM, 1995, ANN NY ACAD SCI, V771, P655; Pejic RN, 2006, HEART, V92, P1529; Pellett Peter L., 2004, Food and Nutrition Bulletin, V25, P107; PREGNOLATO P, 1994, INT J VITAM NUTR RES, V64, P263; Rahbar AR, 2005, EUR J CLIN NUTR, V59, P592, DOI 10.1038-sj.ejcn.1602109; SHEPARD DC, 1985, BIOCHEM ARCH, V1, P143; Sulochana KN, 2001, IND J BIOCH BIOPHY, V18, P277; Sulochana KN, 2002, MED SCI MONITOR, V8, pR132; TANPHAICHITR V, 1976, J NUTR, V106, P111; Tome D, 2007, J NUTR, V137, p1642S; TULLY DB, 1994, FASEB J, V8, P343; Vaz FM, 2002, BIOCHEM J, V361, P417, DOI 10.1042-0264-6021:3610417; Yuan G, 2007, CAN MED ASSOC J, V176, P1113, DOI 10.1503-cmaj.06096343
The origins of G12P[6] rotavirus strains detected in Lebanon
No full textThe G12 rotaviruses are an increasingly important cause of severe diarrhoea in infants and young children worldwide. Seven human G12P[6] rotavirus strains were detected in stool samples from children hospitalized with gastroenteritis in Lebanon during a 2011–2013 surveillance study. Complete genomes of these strains were sequenced using VirCapSeq-VERT, a capture-based high-throughput viral-sequencing method, and further characterized based on phylogenetic analyses with global RVA and vaccine strains. Based on the complete genomic analysis, all Lebanese G12 strains were found to have Wa-like genetic backbone G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Phylogenetically, these strains fell into two clusters where one of them might have emerged from Southeast Asian strains and the second one seems to have a mixed backbone between North American and Southeast Asian strains. Further analysis of these strains revealed high antigenic variability compared to available vaccine strains. To our knowledge, this is the first report on the complete genome-based characterization of G12P[6] emerging in Lebanon. Additional studies will provide important insights into the evolutionary dynamics of G12 rotaviruses spreading in Asia. © 2021 The Author
