ABSTRACT In this paper, we present the frequency and voltage dependence of the capacitance in met... more ABSTRACT In this paper, we present the frequency and voltage dependence of the capacitance in metal-insulator-semiconductor (MIS) structures fabricated with polymethyl-methacrylate (PMMA), as dielectric and three semiconductor polymers: poly(3-hexylthiophene), poly [N-9”-hepta-decanyl-2, 7-carbazole-ALT-5, 5-(4' 7' di-2-thienyl-2' 1' 3' benzothiadiazole)], and poly[(9, 9-dioctylfluorenyl-2, 7-diyl)-CO-bithiophene]. It is shown that the dielectric constant of PMMA varies in the frequency range <; 1 MHz. In addition, the effect of the not yet depleted semiconductor can become important even in relatively thin layers and the presence of series resistance at the contacts can significantly modify the behavior of the capacitance-voltage (CV) curves. The calculated CV curves, in which specific material and interface properties are taken into account, are compared with the measured ones to identify the effects that determine the behavior of the capacitance with voltage and frequency for each analyzed MIS structure.
The identity of two insular populations of rodents of the nominal species, Zygodontomys brevicaud... more The identity of two insular populations of rodents of the nominal species, Zygodontomys brevicauda (Allen & Chapman, 1893), from the Veragua Archipelago was examined. The mitochondrial cytochrome-b gene was sequenced from specimens collected on Isla Coiba (n = 10), Isla Cébaco (n = 3) and on the nearby Peninsula Azuero (n = 3) in Panama and compared with sequences of Z. brevicauda and a number of other related species from GenBank. For Panama, phylogenetic analyses identified two clades within Zygodontomys Allen, 1897; one representing Isla Coiba and another clade composed of rats from Isla Cébaco and from the mainland on the Peninsula Azuero, as well as a GenBank sequence of Z. brevicauda from Venezuela. We suggest that the population from Isla Coiba may represent a previously undescribed species of sigmodontine rodent that is endemic to this Pacific Island.
MD, R o b e r t B. Smith III, MD, and S. T i m o t h y String, MD, , Ga.; Raleigh and Winston-Sal... more MD, R o b e r t B. Smith III, MD, and S. T i m o t h y String, MD, , Ga.; Raleigh and Winston-Salem, N.C.; Tamarac, Tampa, and West Palm Beach, Fla.; Birmingham and Mobile, Ala.; Dallas, Tex.; Madisonville, Ky.; Richmond, Va.; and Baltimore, Md. Purpose: Recurrent carotid stenosis after carotid endarterectomy has been extensively reported. The occurrence, however, of another ipsilateral restenosis that requires a third carotid operation is rare. The purpose of this study was to evaluate possible risk factors and the most efficacious management of the patient with "secondary" recurrent carotid stenosis.
Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupial... more Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupials and 22 rodents) were collected in Panama between February 2000 and July 2002. The samples were examined for antibodies to hantaviruses by means of enzymelinked immunosorbent assay or immunoblot assays. The serologic results indicated that several rodent species might act as hantaviral reservoirs in Panama: Costa Rican pygmy rice rat (Oligoryzomys fulvescens costaricensis), four positive of 72 tested (5.6%); Cherrie's cane rat (Zygodontomys brevicauda cherriei), five of 108 (4.6%); Mexican deer mouse (Peromyscus mexicanus), one of 22 (5%); Mexican harvest mouse (Reithrodontomys mexicanus), one of seven (14%); Chiriquí harvest mouse (Reithrodontomys creper), one of two (50%); and Sumichrast's harvest mouse (Reithrodontomys sumichrasti), three of four (75%). Hantavirus infection in Peromyscus mexicanus and the three species of Reithrodontomys was caused by Rio Segundo hantavirus, a species of virus not previously reported from Panama. At least three hantaviruses, therefore, are known to infect populations of wild rodents in the country. However, given the total number of animals tested, the role of these rodent species in the epidemiology and epizootiology of hantavirus infections remains unclear.
Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupial... more Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupials and 22 rodents) were collected in Panama between February 2000 and July 2002. The samples were examined for antibodies to hantaviruses by means of enzymelinked immunosorbent assay or immunoblot assays. The serologic results indicated that several rodent species might act as hantaviral reservoirs in Panama: Costa Rican pygmy rice rat (Oligoryzomys fulvescens costaricensis), four positive of 72 tested (5.6%); Cherrie's cane rat (Zygodontomys brevicauda cherriei), five of 108 (4.6%); Mexican deer mouse (Peromyscus mexicanus), one of 22 (5%); Mexican harvest mouse (Reithrodontomys mexicanus), one of seven (14%); Chiriquí harvest mouse (Reithrodontomys creper), one of two (50%); and Sumichrast's harvest mouse (Reithrodontomys sumichrasti), three of four (75%). Hantavirus infection in Peromyscus mexicanus and the three species of Reithrodontomys was caused by Rio Segundo hantavirus, a species of virus not previously reported from Panama. At least three hantaviruses, therefore, are known to infect populations of wild rodents in the country. However, given the total number of animals tested, the role of these rodent species in the epidemiology and epizootiology of hantavirus infections remains unclear.
We predicted that more-fragmented habitats are associated with lower diversity of small mammals a... more We predicted that more-fragmented habitats are associated with lower diversity of small mammals and higher densities of populations of rodents that are hosts of hantaviruses. We compared diversity and distribution of small mammals that are either hosts or nonhosts of hantaviruses in 6 Panamanian national parks and adjacent areas with varying degree of human impacts. We sampled forest, edge, and anthropogenically disturbed habitats. The generalist rodents Oligoryzomys fulvescens (reservoir of Choclo virus) and Zygodontomys brevicauda (reservoir of Calabazo virus) were more abundant in disturbed habitats, especially in smaller and more isolated patches, where population density and diversity of other rodent species was lowest. In contrast, these 2 species had lower abundances in larger forested areas with more nonreservoir species of small mammals. Our results suggest that the change in the natural environment resulting from tropical deforestation is increasing the abundance and distribution of species that are reservoirs for hantaviruses. Therefore, it is likely that forest fragmentation has contributed to recent outbreaks of hantavirus pulmonary syndrome in tropical areas. Conservation of natural resources becomes all the more imperative, not only for protecting fauna and flora but also for human health.
To determine causes of treatment resistance in patients with refractory hypertension, and to esti... more To determine causes of treatment resistance in patients with refractory hypertension, and to estimate the prevalence of true resistant hypertension. We studied 50 consecutive patients referred with refractory hypertension after exclusion of hypokalemia and stenosis of the renal artery. Ambulatory blood pressure monitoring was performed in all patients to detect white-coat effect. The patients were hospitalized, antihypertensive drugs were withdrawn and a screening for secondary hypertension was performed. In addition, these patients, and a control group of essential hypertensives controlled with three antihypertensive drugs, underwent a OGTT with 75 g of glucose. Primary normokalemic hyperaldosteronism was diagnosed in seven patients. Two patients had a pheochromocytoma and six had white-coat effect. The 35 remaining patients with true resistant hypertension shown significant differences in serum insulin and HOMA IR when compared with the control group. These findings show that among normokalemic treatment-resistant hypertension, the presence of hyperaldosteronism and pheochromocytoma is quite high. Moreover, treatment resistance in hypertensive patients appears to be associated with insulin resistance.
ABSTRACT In this paper, we present the frequency and voltage dependence of the capacitance in met... more ABSTRACT In this paper, we present the frequency and voltage dependence of the capacitance in metal-insulator-semiconductor (MIS) structures fabricated with polymethyl-methacrylate (PMMA), as dielectric and three semiconductor polymers: poly(3-hexylthiophene), poly [N-9”-hepta-decanyl-2, 7-carbazole-ALT-5, 5-(4' 7' di-2-thienyl-2' 1' 3' benzothiadiazole)], and poly[(9, 9-dioctylfluorenyl-2, 7-diyl)-CO-bithiophene]. It is shown that the dielectric constant of PMMA varies in the frequency range <; 1 MHz. In addition, the effect of the not yet depleted semiconductor can become important even in relatively thin layers and the presence of series resistance at the contacts can significantly modify the behavior of the capacitance-voltage (CV) curves. The calculated CV curves, in which specific material and interface properties are taken into account, are compared with the measured ones to identify the effects that determine the behavior of the capacitance with voltage and frequency for each analyzed MIS structure.
The identity of two insular populations of rodents of the nominal species, Zygodontomys brevicaud... more The identity of two insular populations of rodents of the nominal species, Zygodontomys brevicauda (Allen & Chapman, 1893), from the Veragua Archipelago was examined. The mitochondrial cytochrome-b gene was sequenced from specimens collected on Isla Coiba (n = 10), Isla Cébaco (n = 3) and on the nearby Peninsula Azuero (n = 3) in Panama and compared with sequences of Z. brevicauda and a number of other related species from GenBank. For Panama, phylogenetic analyses identified two clades within Zygodontomys Allen, 1897; one representing Isla Coiba and another clade composed of rats from Isla Cébaco and from the mainland on the Peninsula Azuero, as well as a GenBank sequence of Z. brevicauda from Venezuela. We suggest that the population from Isla Coiba may represent a previously undescribed species of sigmodontine rodent that is endemic to this Pacific Island.
MD, R o b e r t B. Smith III, MD, and S. T i m o t h y String, MD, , Ga.; Raleigh and Winston-Sal... more MD, R o b e r t B. Smith III, MD, and S. T i m o t h y String, MD, , Ga.; Raleigh and Winston-Salem, N.C.; Tamarac, Tampa, and West Palm Beach, Fla.; Birmingham and Mobile, Ala.; Dallas, Tex.; Madisonville, Ky.; Richmond, Va.; and Baltimore, Md. Purpose: Recurrent carotid stenosis after carotid endarterectomy has been extensively reported. The occurrence, however, of another ipsilateral restenosis that requires a third carotid operation is rare. The purpose of this study was to evaluate possible risk factors and the most efficacious management of the patient with "secondary" recurrent carotid stenosis.
Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupial... more Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupials and 22 rodents) were collected in Panama between February 2000 and July 2002. The samples were examined for antibodies to hantaviruses by means of enzymelinked immunosorbent assay or immunoblot assays. The serologic results indicated that several rodent species might act as hantaviral reservoirs in Panama: Costa Rican pygmy rice rat (Oligoryzomys fulvescens costaricensis), four positive of 72 tested (5.6%); Cherrie's cane rat (Zygodontomys brevicauda cherriei), five of 108 (4.6%); Mexican deer mouse (Peromyscus mexicanus), one of 22 (5%); Mexican harvest mouse (Reithrodontomys mexicanus), one of seven (14%); Chiriquí harvest mouse (Reithrodontomys creper), one of two (50%); and Sumichrast's harvest mouse (Reithrodontomys sumichrasti), three of four (75%). Hantavirus infection in Peromyscus mexicanus and the three species of Reithrodontomys was caused by Rio Segundo hantavirus, a species of virus not previously reported from Panama. At least three hantaviruses, therefore, are known to infect populations of wild rodents in the country. However, given the total number of animals tested, the role of these rodent species in the epidemiology and epizootiology of hantavirus infections remains unclear.
Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupial... more Five hundred fifty-six samples representing 24 species of small mammals (two species of marsupials and 22 rodents) were collected in Panama between February 2000 and July 2002. The samples were examined for antibodies to hantaviruses by means of enzymelinked immunosorbent assay or immunoblot assays. The serologic results indicated that several rodent species might act as hantaviral reservoirs in Panama: Costa Rican pygmy rice rat (Oligoryzomys fulvescens costaricensis), four positive of 72 tested (5.6%); Cherrie's cane rat (Zygodontomys brevicauda cherriei), five of 108 (4.6%); Mexican deer mouse (Peromyscus mexicanus), one of 22 (5%); Mexican harvest mouse (Reithrodontomys mexicanus), one of seven (14%); Chiriquí harvest mouse (Reithrodontomys creper), one of two (50%); and Sumichrast's harvest mouse (Reithrodontomys sumichrasti), three of four (75%). Hantavirus infection in Peromyscus mexicanus and the three species of Reithrodontomys was caused by Rio Segundo hantavirus, a species of virus not previously reported from Panama. At least three hantaviruses, therefore, are known to infect populations of wild rodents in the country. However, given the total number of animals tested, the role of these rodent species in the epidemiology and epizootiology of hantavirus infections remains unclear.
We predicted that more-fragmented habitats are associated with lower diversity of small mammals a... more We predicted that more-fragmented habitats are associated with lower diversity of small mammals and higher densities of populations of rodents that are hosts of hantaviruses. We compared diversity and distribution of small mammals that are either hosts or nonhosts of hantaviruses in 6 Panamanian national parks and adjacent areas with varying degree of human impacts. We sampled forest, edge, and anthropogenically disturbed habitats. The generalist rodents Oligoryzomys fulvescens (reservoir of Choclo virus) and Zygodontomys brevicauda (reservoir of Calabazo virus) were more abundant in disturbed habitats, especially in smaller and more isolated patches, where population density and diversity of other rodent species was lowest. In contrast, these 2 species had lower abundances in larger forested areas with more nonreservoir species of small mammals. Our results suggest that the change in the natural environment resulting from tropical deforestation is increasing the abundance and distribution of species that are reservoirs for hantaviruses. Therefore, it is likely that forest fragmentation has contributed to recent outbreaks of hantavirus pulmonary syndrome in tropical areas. Conservation of natural resources becomes all the more imperative, not only for protecting fauna and flora but also for human health.
To determine causes of treatment resistance in patients with refractory hypertension, and to esti... more To determine causes of treatment resistance in patients with refractory hypertension, and to estimate the prevalence of true resistant hypertension. We studied 50 consecutive patients referred with refractory hypertension after exclusion of hypokalemia and stenosis of the renal artery. Ambulatory blood pressure monitoring was performed in all patients to detect white-coat effect. The patients were hospitalized, antihypertensive drugs were withdrawn and a screening for secondary hypertension was performed. In addition, these patients, and a control group of essential hypertensives controlled with three antihypertensive drugs, underwent a OGTT with 75 g of glucose. Primary normokalemic hyperaldosteronism was diagnosed in seven patients. Two patients had a pheochromocytoma and six had white-coat effect. The 35 remaining patients with true resistant hypertension shown significant differences in serum insulin and HOMA IR when compared with the control group. These findings show that among normokalemic treatment-resistant hypertension, the presence of hyperaldosteronism and pheochromocytoma is quite high. Moreover, treatment resistance in hypertensive patients appears to be associated with insulin resistance.
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