NANOPARTICLES OF TUNGSTEN AS LOW-COST MONOMETALLIC CATALYST FOR SELECTIVE HYDROGENATION OF 3-HEXYNE

Low-cost tungsten monometallic catalysts containing variable amounts of metal (4.5, 7.1 and 8.5%W) were prepared by impregnating alumina with ammonium metatungstate as an inexpensive precursor. The catalysts were characterized using ICP, XPS, XRD, TPR and hydrogen chemisorption. These techniques revealed mainly WO3-Al2O3 (W6+) species on the surface. The effects of the content of W nanoparticles and reaction temperature on activity and selectivity for the partial hydrogenation of 3-hexyne, a non-terminal alkyne, were assessed under moderate conditions of temperature and pressure. The monometallic catalysts prepared were found to be active and stereoselective for the production of (Z )-3-hexene, had the following order: 7.1WN/A > 8.5 WN/A ≥ 4.5 WN/A. Additionally, the performance of the synthesized xWN/A catalysts exhibited high sensitivity to temperature variation. In all cases, the maximum 3-hexyne total conversion and selectivity was achieved at 323 K. The performance of the catalysts was considered to be a consequence of two phenomena: a) the electronic effects, related to the high charge of W (+6), causing an intensive dipole moment in the hydrogen molecule (van der Waals forces) and leading to heterolytic bond rupture; the H+ and H- species generated approach a 3-hexyne adsorbate molecule and cause heterolytic rupture of the C≡C bond into C- = C+; and b) steric effects related to the high concentration of WO3 on 8.5WN/A that block the Al2O3 support. Catalyst deactivation was detected, starting at about 50 min of reaction time. Electrodeficient W6+ species are responsible for the formation of green oil at the surface level, blocking pores and active sites of the catalyst, particularly at low reaction temperatures (293 and 303 K). The resulting best catalyst, 7.1WN/A, has low fabrication cost and high selectivity for (Z )-3-hexene (94%) at 323 K. This selectivity is comparable to that of the classical and more expensive industrial Lindlar catalyst (5 wt% Pd). The alumina supported tungsten catalysts are low-cost potential replacements for the Lindlar industrial catalyst. These catalysts could also be used for preparing bimetallic W-Pd catalysts for selective hydrogenation of terminal and non-terminal alkynes.

Resultados científicos do cruzeiro do "Baependi" e do "Vega" à Ilha da Trindade: contribuição para o conhecimento da plataforma insular da Ilha da Trindade

The oceanographic work realized during 10 days in the surroundings of the eruptive island of Trindade, 20º30'36" lat. S - 29º19'26" long. W, had as principal aim the determination of the insular plateau, whose knowledge was very insufficient. Thus were established some oceanographic stations and sounding lines were realized by means of an echobathymeter whose responses were initially verified with mechanical soundings obtaneid by means of a Thomson sounder. The insular plateau is very narrow and exhibits a sudden fall between the 100 and 120 m. depth line at 740 m. - 2950 m. from the coast. Its greatest depth is of 108,30 m. and its mean inclination is of 8,12%. The plateau of the island of Trindade is separated from that of the neighbouring group of Martim Yaz by great depths. The bottoms are rocky near the coast, the blocks having been produced by the rupture of the magmatic mass of the island. Further away from the coast, the size of the rocks gradually diminishes up to the fine sand thickness. In the litoral zone there are abundant tufts of living Lithothamnion with a rich associated flora and fauna, which partly covers the rocks themselves. Further off at sea, the spheres of the dead alga with its commensals are cimented together by sedimentation. The spheres are further broken up and become an integrating part of the sand. The results of the physical and chemical analyses of the sand bottoms are shown in tables 2 and 3. The coast is either of abrupt rocky walls falling down to sea level, or of shores, made of pebbles or of sand. Anyhow, there are frequently Lithothamnion terraces slightly inclinated towards the bottom (chemical analysis table 1).

Early detection of injuries in leaves of Clusia hilariana Schltdl. (Clusiaceae) caused by particulate deposition of iron

This study aims to evaluate the prognostic value of microscopic parameters of asymptomatic leaves of Clusia hilariana Schltdl. subjected to particulate deposition of iron (2.14 mg cm-2 day-1) for 45 consecutive days. Samples of young and expanded leaves without symptoms were collected and subjected to light and scanning electron microscopy techniques. The height of the epidermal cells on both surfaces of the leaf and the thickness of the hypodermis, the chlorophyll parenchyma, and the leaf blade were measured. Micromorphological injury occurred in the abaxial surface of young leaves and on both surfaces of expanded leaves. Erosion of the epicuticular wax and cuticle rupture were frequent on the adaxial surface, while on the abaxial surface of both leaves there was a loss of sinuosity on the anticlinal wall of the epidermal cells, stomatal deformity and obstruction. Micromorphometric alterations were seen in all leaf tissues except in the height of epidermic cells, probably due to the thick cuticle and prominent cuticular flanges. The highest difference in thickness of the leaf blade was seen in young leaves of plants subjected to SPMFe, indicating greater sensibility to particulate iron in comparison to the expanded leaves. The micromorphological and micromorphometric alterations in the leaf blade of Clusia hilariana Schltdl. showed the prognostic potential of these tools on the evaluation of impacts caused by the deposition of particulate matter, especially in the 'Restinga' natural vegetation, where the exposure is increasing due to the presence of iron ore industry in their surroundings.

Mechanical properties of castor beans subject to different drying temperatures aiming to disrupt the bean coat

In castor oil extraction process, the bean coat is abrasive to the equipment and releases substances that modify the oil color, reducing its quality. A potential solution would be to run the extraction by compressing only the endosperm. Due to lack of information, the objective of this study was to evaluate the influence of forced air drying at 40, 60, 80 and 100 ºC and farmyard drying, in the mechanical properties of the beans, aiming to break the bean coat. Castor beans were subjected to compression tests, in two perpendicular directions, at a strain rate of 0.6 mm.s-1. Average values of force, deformation energy, strain, all at rupture, and stiffness were used to evaluate the effects of dehydration. It was observed that the heat treatments did not alter the mechanical properties of castor beans, the strain and stiffness values discriminate the differences between the directions and had the lowest coefficients of variation. It was concluded that forced air drying, more costly than farmyard drying, does not bring benefits to the decortication. However, regardless the heat treatment used, the mechanical stress lengthwise is the most suitable to promote decortication.

Cisto esplênico não-parasitário e não-neoplásico

The authors present a rare case of pathology from spleen, a nonparasitic, non-neoplastic splenic cyst, in an adult male patient without a previous history of abdominal trauma. Principal clinical findings were pain in left upper quadrant, nausea, regurgitation and precocious satiation. On investigation, ultrasonography and CT scan showed an expansive lesion in the spleen, compressing the stomach. Surgical procedure was splenectomy and a microscopical examination revealed a non- parasitic, non-neoplastic splenic cyst. Splenic cysts are usually benigns, but surgical remotion is necessary when they are symptomatic or exist risk of rupture. In this report is presented the classification of splenic cysts, clinical manifestations, diagnostics methods and discussed their surgical treatment.

Pseudo-aneurisma gigante de artéria axilar esquerda

A case of a gunshot of the left axilary artery with a giant pseudoaneurism formation with sixteen years of evolution is presented. The 61- years-old male patient present since them a small assintomatic tumoration in infraclavicular localization. In the last eight months the tumor became symptomatic and volumous, reaching 20 cm in diameter, with signals of infection and imminent rupture. The patient was operated on with ligature of the axilary artery and evacuation of the pseudoaneurysm. The surgical handling and endovascular therapeutic options available in the present time are discussed. A short review about the disease as well as a bibliographic update are present. The authors also call attention for the necessity of a correct management of the vascular injures in the event of the first management.

Hemosuccus pancreaticus: causa rara de hemorragia digestiva maciça

Hemosuccus pancreaticus is a unusual syndrome manifested by hemorrhage into the pancreatic duct and by blood loss through the ampulla of Vater: It may be caused by tumors, arteriovenous malformation, pancreatic lithiasis, aneurism rupture from adjacent vessels, or erosion of pancreatic and peripancreatic vessels due to chronic pancreatitis. The authors describe a case of massive and recurrent gastrointestinal upper hemorrhage in a 26-year-old man without known risk factors for pancreatitis. This man underwent urgent surgery due to gastrointestinal bleeding during the ínvestigation. During the procedure, blood was found in the intestinal lumen and a tumor in the head of pancreas with two centimeters of diameter: A gastroduodenopancreatectomy was performed. Histological study showed chronic pancreatitis with a fistula from the pancreatic vessels to the Wirsung duct. The patient was discharged without postoperative complications and after months, remains assymptomatic.

Lipídios plasmáticos após esplenectomia total e parcial em cães

OBJETIVO: Avaliar o efeito da esplenectomia total e parcial (hemiesplenectomia e esplenectomia subtotal) no lipidograma de cães. MÉTODO: Foram operados 38 animais, adultos, machos, mestiços, com peso entre 13kg e 15kg. No pré-operatório, depois do exame clínico e jejum de 12 horas de uma dieta-padrão, foram realizados hemograma e lipidograma. Após anestesia geral com tiopental sódico os cães foram submetidos à laparotomia mediana supra e infra-umbilical. Procedeu-se no grupo 1, de sete cães, apenas à manipulação do baço (simulado); no grupo 2, de nove cães, à hemiesplenectomia cranial; no grupo 3, de nove cães, à esplenectomia subtotal, com preservação do pólo inferior do baço, após ligadura e secção dos troncos principais dos vasos esplênicos próximos ao hilo; e no grupo 4, de 13 cães, à esplenectomia total. RESULTADOS: No grupo 4 (esplenectomia total), quando comparamos os valores do lipidograma dos diferentes períodos pós-operatórios com os do pré-operatório, os nossos resultados mostraram que houve aumento significante do colesterol total em todos os períodos pós-operatórios (p < 0,05, p < 0,01). O HDL aumentou significantemente no 7º (p < 0,01) e 28º dias de pós-operatório (PO) (p < 0,05), e não significantemente (p>0,05) no 56º PO. O LDL aumentou significantemente no 56º PO (p < 0,01) em relação também aos demais períodos do pós-operatório. Os triglicerídeos e VLDL não apresentaram alterações significantes. Nos animais dos grupos 1 e 3 não houve alterações significantes. Nos do grupo 2, houve aumento significante do colesterol no 7º PO. Não houve diferença estatisticamente significante de peso entre os remanescentes das esplenectomias parciais. CONCLUSÕES: A análise dos resultados nos permitiu concluir que a esplenectomia total induz aumento significante do colesterol total, das frações HDL e LDL, enquanto os níveis de triglicerídios e a fração VLDL não sofrem alterações; a conservação da metade inferior do baço ou a esplenectomia subtotal, com preservação do pólo inferior, protege o animal de alterações lipídicas significantes.

Hérnia diafragmática traumática

Traumatic diaphragmatic hernia is an uncommon but important problem in the patient with multiple injuries. Since diaphragmatic injuries are difficult to diagnose, those that are missed may present with latent symptoms of bowel obstruction and strangulation. The same may occur in the patients with stab wounds to the lower chest. Traumatic diaphragmatic hernia should be suspected on the basis of an abnormal chest radiograph in the trauma victim with multiple injuries. This article discuss about history, epidemiology, clinical signs and symptoms, diagnostic modalities, treatment and complications.

Aneurisma roto de artéria esplênica: flagrante tomográfico de sangramento

The splenic artery aneurysm is a rare entity and its rupture is the most feared complication. The tomographic computed scan is a potential tool in the diagnosis, and can be used to patients with a suspicion of intra-abdominal bleeding, after adequate resuscitation. A case of a 68-year old male, hypertense patient, with a ruptured splenic artery aneurysm is reported. The diagnosis and treatment were given successfully by the abdominal computed tomographic scan and conventional surgery. The tomographic computed scan can be useful to the diagnosis of ruptured splenic artery aneurism, after the hemodynamic stabilization.

Suplência vascular do sexto arco costal através dos músculos peitoral menor e serrátil anterior

OBJETIVO: Estudar a suplência vascular do sexto arco costal, através de injeção de corante no segmento da artéria axilar que nutre os músculos peitoral menor e serrátil anterior. MÉTODO: Realizada dissecção de retalho osteomuscular em 20 cadáveres frescos, 19 do sexo masculino e um do sexo feminino, com idade variando de 43 a 60 anos e peso entre 55 a 80kg, contendo os músculos peitoral menor na parte cranial e o serrátil anterior na parte caudal, além da sexta costela na parte distal. Com o retalho elevado e destacado do tórax, e as aderências osteomusculares intactas, foi injetado sob pressão um corante hidrossolúvel - látex azul - na artéria axilar até observar-se a coloração dos vasos periostais. O arco costal foi fotografado com os vasos periostais corados e descalcificado em solução de ácido nítrico a 5% e diluído em formalina a 10% para estudo histológico. RESULTADOS: Em todos os cadáveres dissecados encontramos positividade pelo corante nos vasos periostais, como comprovação histológica. CONCLUSÕES: A presença de corante nos vasos periostais demonstra que esta rota de fluxo sangüínea pode viabilizar um retalho osteomuscular para reconstrução de face e mandíbula.

Pseudoaneurisma gigante de artéria esplênica

Splenic artery pseudoaneurysm larger than 10 cm is a rare condition. The risk of rupture is probably high and surgical treatment is necessary. The objective of this article is to report a case of a patient with giant pseudoaneurysm of the splenic artery submitted to surgical resection. A 26-year-old man complaining of gastrointestinal hemorrhage and abdominal pain The patient’s medical history revealed that one year before he had an abdominal blunt trauma. The angiography showed a giant pseudoaneurysm of the splenic artery with compression of the stomach. The patient was operated on by abdominal access and the spleen and pseudoaneurysm were resected. The postoperative course was uneventful and the patient was discharged 13 days after surgery without problems.

Perfuração espontânea de ducto hepático comum

Perforation of common bile duct (CBD) is usually associated with invasive procedures. Spontaneous perforation is rare, and more often described in neonates. We report a case of a spontaneous perforation of CBD in an adult with a family history of cholelithiasis, but with no calculus found during exploration of the biliary tree. The patient was successfully treated by cholecystectomy and T - tube drainage of the CBD.

Rotura gástrica por barotrauma

Barogenic rupture of the stomach is a rare complication following cardiopulmonary resuscitation, administration of nasal oxygen by catheter and diving accidents. We report a case of gastric barotrauma following oroesophageal intubation. In most cases, the tears occur along the lesser curvature, what have been already attributed to Laplace's formula and, more recently, to morphological features of the stomach.

Ruptura isolada da pelve renal secundária ao trauma abdominal contuso

Blunt rupture of the renal pelvis is a exceedingly rare injury. Hematuria is absent in one-third of cases. Such injuries are usually caused by desacceleration forces. Despite improved imaging techniques, diagnosis of this injuries is frequently delayed. Diagnosis is suggested by the presence of massive medial extravasation of contrast material at excretory urography or computed tomography. Surgical treatment consists in pyeloplasty or pyeloraphy with stent placement (double J) or nephrostomy.