40 K Neon liquid energy storage unit

Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices, implemented as a software,describes quite well the experimental results. Solutions to improve these devices are also proposed.

40 K neon liquid energy storage unit

Cryocoolers have been progressively replacing the use of the stored cryogens in cryogenic chains used for detector cooling, thanks to their higher and higher reliability. However, the mechanical vibrations, the electromagnetic interferences and the temperature fluctuations inherent to their functioning could reduce the sensor’s sensitivity. In order to minimize this problem, compact thermal energy storage units (ESU) are studied, devices able to store thermal energy without significant temperature increase. These devices can be used as a temporary cold source making it possible to turn the cryocooler OFF providing a proper environment for the sensor. A heat switch is responsible for the thermal decoupling of the ESU from the cryocooler’s temperature that increases when turned OFF. In this work, several prototypes working around 40 K were designed, built and characterized. They consist in a low temperature cell that contains the liquid neon connected to an expansion volume at room temperature for gas storage during the liquid evaporation phase. To turn this system insensitive to the gravity direction, the liquid is retained in the low temperature cell by capillary effect in a porous material. Thanks to pressure regulation of the liquid neon bath, 900 J were stored at 40K. The higher latent heat of the liquid and the inexistence of triple point transitions at 40 K turn the pressure control during the evaporation a versatile and compact alternative to an ESU working at the triple point transitions. A quite compact second prototype ESU directly connected to the cryocooler cold finger was tested as a temperature stabilizer. This device was able to stabilize the cryocooler temperature ((≈ 40K ±1 K) despite sudden heat bursts corresponding to twice the cooling power of the cryocooler. This thesis describes the construction of these devices as well as the tests performed. It is also shown that the thermal model developed to predict the thermal behaviour of these devices,implemented as a software, describes quite well the experimental results. Solutions to improve these devices are also proposed.

Toyota RAV4 model year marketing plan for the U.K

NSBE - UNL

Efficacy of voriconazole in experimental rat paracoccidioidomycosis

INTRODUCTION: Amphotericin B, azole or sulfamide drugs are used for treatment of patients with paracoccidioidomycosis. Among the azole drugs, voriconazole was active in vitro against Paracoccidioides brasiliensis and showed efficacy in the treatment of patients infected with this fungus.In the present study the antifungal activity of voriconazole and of other drugs was compared in a rat model of paracoccidioidomycosis. METHODS: Wistar rats were inoculated intravenously with the BOAS strain of P. brasiliensis and antifungal drugs were administered to the animals by gavage at the following doses (mg/kg weight/day): voriconazole (5 to 20), ketoconazole (12 to 15), fluconazole (6), itraconazole (4), and sulfamethoxazole-trimethoprim (120 to 150). The antifungal activity of the drugs was assessed by determining the P. brasiliensis colony forming units in the lungs and spleen of the animals at the end of treatment and by a survival study. RESULTS: Voriconazole reduced the total tissue fungal burden of P. brasiliensis, particularly at doses of ≥10mg/kg weight/day but its antifungal activity was less intense than that of fluconazole, itraconazole and sulfamethoxazole-trimethoprim. The mean survival of animals treated with the last three drugs, 29.1±10.7, 26.1± 10.1 and 28.4±9.6 days, respectively, was higher than that achieved with voriconazole 10mg/kg weight/day (18.5±8.3 days) and that observed in untreated animals (15.7±3.6 days). CONCLUSIONS: At doses similar to those used for clinical treatment, voriconazole showed lower antifungal activity in experimental rat paracoccidioidomycosis than that obtained with itraconazole and sulfamethoxazole-trimethoprim.

Harry Potter – O rapazque sobreviveu : Uma leitura psicanalítica daobra de J. K. Rowling

Dissertação de Mestrado apresentada ao ISPA - Insituto Universitário

Detection of codon 12 mutation in the k-ras oncogene in pancreatic tumors

Mutations at codons 12, 13, or 61 of the H-ras, K-ras, and N-ras have been detected in human neoplasias by a variety of techniques. Some of these techniques are very sensitive and can detect K-ras mutation in 90% of the cases of pancreatic adenocarcinomas. We analyzed 11 samples of pancreatic adenocarcinoma, three samples of pancreatic mucinous cystadenoma, and two samples without tumors in formalin-fixed paraffin embedded tissue sections. K-ras mutations at codon 12 were detected by a two-step PCR-enriched technique in all the samples of pancreatic adenocarcinoma, but not in cystadenoma or control samples. This technique may be useful for early detection of pancreatic cancer.

Rat allotransplantation of epigastric microsurgical flaps: a study of rejection and the immunosuppressive effect of cyclosporin A

The rejection of allotransplantation of epigastric microsurgical flaps and the effect of immunosuppression have been studied in 58 rats. Three sets of experiments were planned: (1) Wistar Furth isogenic donors and receptors (control set); (2) Brown Norway donors and Wistar Furth receptors (rejection set); and (3) Brown Norway donors and Wistar Furth immunosuppressed receptors (cyclosporin A set). Cyclosporin A (10 mg/kg/d) treated rats had a transplantation survival rate of up to 30 days: 83.3% among isogenic animals and 60% among allogeneic. There was 100% rejection by the 9th day after the transplantation in allogeneic non-immunosuppressed rats. Biopsies embedded with historesin were taken from the flap and normal contralateral skin (used as control) on the 3rd, 7th, 15th, and 30th days after the surgery. A quantitative study of infiltrating lymphocytes in the flaps, with and without cyclosporin A, was done by evaluating the local inflammatory infiltrate. A significant increase in the number of lymphocytes among the rejection and immunosuppressed groups was seen, as compared to the isogenic set. Local lymphocytosis in allogeneic non-immunosuppressed transplantations reached its highest level on the 3rd day after surgery, before gross findings of rejection, which could only be seen by naked eye on the 5th or 6th day. Therefore, we conclude that cyclosporin A is effective in preserving allogenic transplantation in rats. Biopsies of transplanted areas may contribute to earlier diagnosis of the need for immunosuppressive therapy.

The effects of glutamine-supplemented diet on the intestinal mucosa of the malnourished growing rat

Glutamine is the most abundant amino acid in the blood and plays a key role in the response of the small intestine to systemic injuries. Mucosal atrophy is an important phenomenon that occurs in some types of clinical injury, such as states of severe undernutrition. Glutamine has been shown to exert powerful trophic effects on the gastrointestinal mucosa after small bowel resection or transplant, radiation injury, surgical trauma, ischemic injury and administration of cytotoxic drugs. Since no study has been performed on the malnourished animal, we examined whether glutamine exerts a trophic effect on the intestinal mucosa of the malnourished growing rat. Thirty-five growing female rats (aged 21 days) were divided into 4 groups: control - chow diet; malnutrition diet; malnutrition+chow diet; and malnutrition+glutamine-enriched chow diet (2%). For the first 15 days of the experiment, animals in the test groups received a malnutrition diet, which was a lactose-enriched diet designed to induce diarrhea and malnutrition. For the next 15 days, these animals received either the lactose-enriched diet, a regular chow diet or a glutamine-enriched chow diet. After 30 days, the animals were weighed, sacrificed, and a section of the jejunum was taken and prepared for histological examination. All the animals had similar weights on day 1 of experiment, and feeding with the lactose-enriched diet promoted a significant decrease in body weight in comparison to the control group. Feeding with both experimental chow-based diets promoted significant body weight gains, although the glutamine-enriched diet was more effective. RESULTS: The morphological and morphometric analyses demonstrated that small intestinal villous height was significantly decreased in the malnourished group, and this change was partially corrected by the two types of chow-based diet. Crypt depth was significantly increased by malnutrition, and this parameter was partially corrected by the two types of chow-based diet. The glutamine-enriched diet resulted in the greatest reduction of crypt depth, and this reduction was also statistically significant when compared with control animals. CONCLUSIONS: Enteral glutamine has some positive effects on body weight gain and trophism of the jejunal mucosa in the malnourished growing rat.

Low coronary perfusion pressure is associated with endocardial fibrosis in a rat model of volume overload cardiac hypertrophy

Left ventricular hypertrophy following volume overload is regarded as an example of cardiac remodeling without increased fibrosis accumulation. However, infarction is associated with increased fibrosis within the noninfarcted, hypertrophied myocardium, particularly in the subendocardial regions. It is conceivable to suppose that, as also occurs postinfarction, low coronary driving pressure may also interfere with accumulation of myocardial fibrosis following aortocaval fistula. PURPOSE: To investigate the role of acute hemodynamic changes in subsequent deposition of cardiac fibrosis in response to aortocaval fistula. METHOD: Aortocaval fistula were created in 4 groups of Wistar rats that were followed over 4 and 8 weeks: aortocaval fistula 4 and aortocaval fistula 8 (10 rats each) and their respective controls (sham-operated controls - Sh), Sh4 and Sh8 (8 rats each). Hemodynamic measurements were performed 1 week after surgery. Hypertrophy and fibrosis were quantified by myocyte diameter and collagen volume fraction at the end of follow up. RESULT: Compared with Sh4 and Sh8, pulse pressure, left ventricular end-diastolic pressure, and +dP/dt were higher in aortocaval fistula 4 and aortocaval fistula 8, but -dP/dt was similar. Coronary driving pressure (mm Hg), used as an estimate of perfusion pressure, was lower in aortocaval fistula 8 (52.6 ± 4.1) than in Sh8 (100.8 ± 1.3), but comparable between aortocaval fistula 4 (50.0 ± 8.9) and Sh4 (84.8 ± 2.3). Myocyte diameter was greater in aortocaval fistula 8, whereas interstitial and subendocardial fibrosis were greater in aortocaval fistula 4 and aortocaval fistula 8. Coronary driving pressure correlated inversely and independently with subendocardial fibrosis (r² = .86, P <.001), whereas left ventricular systolic pressure (r² = 0.73, P = .004) and end-diastolic pressure (r² = 0.55, P = 012) correlated positively and independently with interstitial fibrosis. CONCLUSION: Coronary driving pressure falls and ventricular pressures increase early after aortocaval fistula and are associated with subsequent myocardial fibrosis deposition.

Induction of experimental mammary carcinogenesis in rats with 7,12-dimethylbenz(a)anthracene

PURPOSE: To test an experimental model of chemical mammary carcinogenesis induction in rats. METHODS: Twenty young virgin Sprague-Dawley female rats, aged 47 days, received 20 mg of 7,12-dimethylbenz(a)anthracene (DMBA) intragastrically by gavage. Afterwards, at 8 and 13 weeks, their mammary glands were examined. At the end of the experiment, the animals were sacrificed, and the mammary tumors were measured and weighed. Tumor fragments were analyzed using light microscopy. RESULTS: Eight weeks after DMBA injection, 16 rats presented at least 1 breast tumor (80%). After 13 weeks, all of them (100%) developed breast carcinomas that were confirmed by histopathological analysis. CONCLUSION: This experimental animal model of chemical mammary induced carcinogenesis is feasible and can be used in further experiments on the role of tumorigenic biomodulator substances.

Caracterização de uma doença fúngica na Castanha-do-Brasil (Bertholletia excelsa H.B.K.)

Neste trabalho, objetivou-se a caracterização de uma enfermidade ainda nova para o Estado do Acre, na castanha-do-brasil (Bertholletia. excelsa), onde, após, exames macro e microscópios, foi constatado que tal doença era causada pelo fungo do gênero Colletotrichumsp. Em pesquisas de laboratório, foi testada a eficiência de quatro produtos químicos: MONCOZEB, BENOMYL, TIABENDAZOLE e PCNB, na inibição do desenvolvimento micelial "in vitro" do fungo Colletotrichumsp. Os resultados indicaram que apenas o Moncozeb não apresentou efeito inibidor sobre o crescimento do fungo. Os demais inibiram totalmente o crescimento micelial do fungo estudado.

Composição de Flores Masculinas de Pupunha (Bactris gasipaes H. B. K., Palmae)

Composition of the male flowers of peach palm(Bactris gasipaes H.E.K., Palmae). Male flowers of, peach palm ore occasionally consumed as a vegetable 0r, mixed with other ingredients, as a condiment. Three sample were analysed to discover their nutritional values. These flowers contain law levels of protein (1.2% and fats (2.8%)and reasonable levels of able levels of carboidrates (15%); nutritional value is low.

Observações sobre autocompatibilidade em pupunha (Bactris gasipaes H.B.K., Palmae)

A pupunha aparentemente, possui duas estratégias que asseguram a sua polinização cruzada. Uma delas parece ser um fator genético quantitativo que inibe a auto-polinização. Para estudar este fator, duas series de polinização controlada foram feitas em duas diferentes populações juvenis. A primeira população apresentou uma media, de 19,2% de auto-compatibilidade, medida em percentagem de frutos férteis produzidos em relação a todas as flores. Entretanto, o coeficiente de variação foi extremamente alto. A polinização aberta em algumas plantas produziu 22% de frutos férteis, com um coeficiente de variação menor, sugerindo que, o " fruit set" foi, em geral, baixo nutria população, naquela vez. A segunda população, apresentou em media 37,62% de auto-compatibilidade, com um coeficiente de variação menor. Variação entre as árvores foi também detectada e mostrou ser considerável. Além do mais, a auto-compatibilidade variou de 0 a 81%, em distribuição normal. 0 uso de plantas juvenis pode ser a razão da alta variabilidade entre plantas. Apesar da pouca auto-compatibilidade encontrada nestas populações, esta característica é recomendada como descritor para bancos de germoplasma e deve ser obtida em plantas adultas para evitar a alta variabilidade juvenil.

Observations on flower visitors to Bertholletia excelsa H.B.K. and Couratari tenuicarpa A.C. Sm. (Lecythidaceae)

Bees visiting flowers of Bertholletia excelsa. (Brazil Nut tree) and Couratari tenuicarpa were collected, their behavior described and the pollen found clinging to their dorsal thorax and stored on their legs was identified. Female bees of Xylocopa frontalis(Olivier) and males of Eulaema mocsaryi (Friese) are apparently effective pollinators of Couratari in igapó near Manaus. Female bees of Euplusia seabrai Moure in litt., Epicharis umbraculata (Fabricius), Epicharis rustica (Olivier) and Eulaema nigrita(Lepeletier), as well as male bees of Eulaema cingulata(Fabricius) and Eulaema nigrita are apparently effective pollinators of adult Brazil Nut trees in the Aleixo plantation near Manaus. Only large bees capable of uncurling the floral androecium can effectively pollinate Couratari or Bertholletia.Pollen analysis indicated that all bees captured carried pollen of the host tree in question and had been foraging on flowers of plant species common in secondary growth. Secondary growth near the Aleixo plantation supports a bee guild which appeared to effectively pollinate almost every flower on the Brazil Nut tree studied. Proximity to primary forest (and to those Euglossine bee species which occur only in primary forest) therefore does not appear to be necessary for pollination of Brazil Nut trees.In the Aleixo plantation chronic low fruit set is probably due to some factor other than pollination. Since natural occurrences of Brazil Nut trees to the north and south of Manaus are associated with a higher soil fertility, low production at the Aleixo plantation may be due to deficiencies of the soil.

Comparação preliminar da área foliar de três acessos depupunha(Bactris gasipaes H.B.K. PALMAE) oriundos de três populações distintas da Amazônia Ocidental

A área foliar é um importante parâmetro de crescimento e está diretamente relacio nada com a produção de frutos. Neste trabalho estimou-se a área foliar da pupunheina (Bactris gasipaes H.B.K.) em três diferentes acessos que representam as populações de Benjamin Constant, Coari e Rio Preto da Eva, no Estado do Amazonas,Brasil. Primeiro com parou-se o coeficiente de regressão entre a área verdadeira e a área retangular dos folíolos para determinar a similaridade entre as pupunheiras da Amazônia e as da América Central. A seguir, estimou-se a área foliar de três folhas/plantas e três plantas/acesso para cada população. O número de folíolos, a média do comprimento e da largura máxima de uma amostra de seis folíolos e um fator de correção, permitem fazer esta estimativa. Determinou-se que os três acessos são significativamente diferentes quanto a este parâme tro, sugerindo que a área foliar e seus componentes são descritores de importância, tan to na descrição de populações como no melhoramento genético da espécie.