683 resultados para Mechanic anastomosis
Resumo:
Buffalo is an important livestock resource, with a great participation in agricultural systems, providing milk, meat, and work power. Umbilical cord is responsible for maternal-fetal nutrients exchange during pregnancy, and its alterations can compromise the fetal development. We investigated ten pregnant uteruses collected from cross-bread buffaloes in different stages of gestation. Pregnancy and fetal age was determined by measuring the apex sacral length and development period was calculated by previously published formula. Umbilical cords were measured for length determination. Umbilical cord vascular net and anastomosis were observed by injection of Neoprene latex. Histological sections of the umbilical cord were studied after stain with HE, picrossirius, toluidine blue, orceine, and PAS reaction. Buffaloes' umbilical cord was formed by two central arteries, an allantois duct and two peripheral veins. The artery wall was composed by large quantity of collagen, elastic fibers, fibroblasts and large number of vasa vasorum. The allantois duct was located between the arteries and presented a great number of small nourishing vessels. Small nourishing vessels should be carefully considered to avoid to be mistaken to the arterials and veins vasa vasorum. Medium length of umbilical cord from buffalos was 11.8cm (minimum of 6.8cm and maximum of 17.4cm).
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Thirty heads with neck segments of turkeys (Meleagris gallopavo) were dissected for a systematic study of the arteries. The frequency of the arteries found was: Cerebral carotid artery, intercarotid anastomosis and internal ophthalmic artery (100%). Caudal branch of the cerebral carotid artery to the right (R) vestigial artery (70%) and developed (30%) and to the left (L) developed (70%) and vestigial artery (30%). Ventral tectal mesencephalic artery in (70%) to R and (30%) to L was the direct branch of the cerebral carotid artery to L (70%) and to R (30%) collateral branch of the developed caudal branch. Basilar artery to L in (70%) and to R (30%) formed from the developed caudal branch; rostral ventral cerebellar artery present (86.7%) and absent (13.3%) to R and L. Caudal ventral cerebellar artery to R single (73.3%), double (23.3%) and triple (3.3%); caudal ventral cerebellar artery to L single (73.3%) and double (26.7%). Dorsal spinal artery branch of caudal ventral cerebellar artery to R (80%) and to L (73.3%). The rostral branch of cerebral carotid artery showed as collateral branches the single caudal cerebral artery to R (100%) and to L (96.7%) while in (3.3%) it was double. The middle cerebral artery was single to R and L (100%). Cerebroethmoidal artery to R and L (100%) with its collateral branch to single rostral cerebral artery (90%) to R and (86.7%) to L and double (10%) to R and (13.3%) to L. Ethmoidal artery to R and to L (100%) single. The cerebral arterial circle was rostrally and caudally opened, so that the cerebral blood supply was exclusively made by the carotid system.
Resumo:
Thirty Meleagris gallopavo heads with their neck segments were used. Animals were contained and euthanized with the association of mebezonium iodide, embutramide and tetracaine hydrochloride (T 61, Intervet ) by intravenous injection. The arterial system was rinsed with cold saline solution (15°C), with 5000IU heparin and filled with red-colored latex. The samples were fixed in 20% formaldehyde for seven days. The brains were removed with a segment of cervical spinal cord and after, the dura-mater was removed and the arteries dissected. The cerebral carotid arteries, after the intercarotid anastomosis, were projected around the hypophysis, until they reached the tuber cinereum and divided into their terminal branches, the caudal branch and the rostral branch. The rostral branch was projected rostrolateralwards and gave off, in sequence, two collateral branches, the caudal cerebral and the middle cerebral arteries and the terminal branch was as cerebroethmoidal artery. The caudal cerebral artery of one antimere formed the interhemispheric artery, which gave off dorsal hemispheric branches to the convex surface of both antimeres. Its dorsal tectal mesencephalic branch, of only one antimere, originated the dorsal cerebellar artery. In the interior of the cerebral transverse fissure, after the origin of the dorsal tectal mesencephalic artery, the caudal cerebral artery emitted occipital hemispheric branches, pineal branches and medial hemispheric branches, on both antimeres. The caudal cerebral artery's territory comprehended the entire surface of the dorsal hemioptic lobe, the rostral surface of the cerebellum, the diencephalic structures, the caudal pole and the medial surface of the cerebral hemisphere and in the convex surface, the sagittal eminence except for its most rostral third. Due to the asymmetry found in the caudal cerebral arteries' ramifications, the models were classified into three types and their respective subtypes.
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Crack formation and growth in steel bridge structural elements may be due to loading oscillations. The welded elements are liable to internal discontinuities along welded joints and sensible to stress variations. The evaluation of the remaining life of a bridge is needed to make cost-effective decisions regarding inspection, repair, rehabilitation, and replacement. A steel beam model has been proposed to simulate crack openings due to cyclic loads. Two possible alternatives have been considered to model crack propagation, which the initial phase is based on the linear fracture mechanics. Then, the model is extended to take into account the elastoplastic fracture mechanic concepts. The natural frequency changes are directly related to moment of inertia variation and consequently to a reduction in the flexural stiffness of a steel beam. Thus, it is possible to adopt a nondestructive technique during steel bridge inspection to quantify the structure eigenvalue variation that will be used to localize the grown fracture. A damage detection algorithm is developed for the proposed model and the numerical results are compared with the solutions achieved by using another well know computer code.
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Tässä kandidaatintyössä tarkastellaan gadget-termin alkuperää ja määritelmää. Gadget voidaan määritellä esimerkiksi siten, että se on uusi mekaaninen tai elektroninen laite jolla on jokin käytännöllinen hyöty, mutta on valtavirran mielestä melko turha. Tässä työssä selvitetään lähdekirjallisuuden avulla pitääkö kyseinen määritelmä paikkaansa. Lisäksi työssä käydään läpi historiassa esiintyviä gadgetteja vuosikymmenittäin aina 1900-luvulta 2010-luvulle asti. Lopuksi tarkastellaan gadgettien kohderyhmää asiasta tehtyjen tutkimusten avulla ja selvitetään onko gadgettien omistajuuteen liitettävissä joitain yleisiä piirteitä.
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This study aimed to control different populations of Digitaria insularisby glyphosate herbicide, isolated and mixed, besides the combination of methods (chemical and mechanical) to manage resistant adult plants. Three experiments were conducted, one in pots which were maintained under non-controlled conditions and two under field conditions. In the experiment in pots, twelve populations of D. insularis were sprayed with isolated glyphosate (1.44 and 2.16 kg a.e. ha-1) and mixed (1.44 and 2.16 kg a.e. ha-1) with quizalofop-p tefuryl (0.12 kg i.a. ha-1). The treatment of 1.44 kg a.e. ha-1 of glyphosate plus 0.12 kg a.i. ha-1 of quizalofop was sufficient for adequate control (>95%) of all populations. Population 11 (area of grain production in Itumbiara, GO) was considered sensitive to glyphosate. Others populations were moderately sensitive or tolerant to the herbicide. In the field, the plants of D. insularis of one of the experiments were mowed and, in the other, there were not. Eight treatments with herbicides [isolated glyphosate (1.44 and 2.16 kg a.e. ha-1) and mixed (1.44 and 2.16 kg a.e. ha-1) with quizalofop-p-tefuryl at 0.12 kg a.i. ha-1), clethodim at 0.108 kg a.i. ha-1) or nicosulfuron at 0.06 kg a.i. ha-1)] were assessed, in combination with or without sequential application of the standard treatment, sprayed 15 days after the first application. The combination of the mechanic control with the application of glyphosate (2.16 and 1.44 kg a.e. ha-1) plus quizalofop-p-tefuryl (0.12 kg a.i. ha-1) or clethodim (0.108 kg a.i. ha-1), associated to the sequential application, was the most effective strategy for the management of adult plants of resistant D. insularis.
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Sodium carboxymethylcellulose (SCMC) has been effective in reducing adhesion formation and corticosteroids reduce the inflammatory process. The objective of this study was to define the intraperitoneal (ip) effects of SCMC combined with intramuscular (im) methylprednisolone on peritoneal adhesion formation and on jejunal anastomosis healing in rats. Twenty Wistar rats (200-350 g) were divided into four groups (N = 5): groups I and III (controls) 5 and 21 days of treatment before sacrifice, respectively; groups II and IV (experimental groups) 5 and 21 days of treatment, respectively. SCMC (1%) was infused into the abdominal cavity and methylprednisolone (10 mg kg-1 day-1) was injected im daily from the day before surgery for animals of groups II and IV. All rats were submitted to a jejunal anastomosis. Sections of the anastomosis were prepared for routine histopathological analysis. The abdominal adhesion of group IV was less intense when compared with group III (P<0.0008). Anastomotic resistance was higher in groups II and IV when compared with groups I and III, respectively (P<0.05). There was no histological difference between groups I and II (exuberant granulation tissue on the serosal surface). Group III presented little peritoneal fibrinous tissue, with numerous thick collagen fibers. Group IV presented extensive although immature young fibrous tissue with rare thick collagen fibers. Sodium carboxymethylcellulose combined with corticosteroids seemed to diminish peritoneal adhesion but did not reduce anastomotic resistance.
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The healing of colorectal anastomoses after irradiation therapy continues to be a major concern. The authors evaluated the healing of rectal anastomoses in a rat model after a preoperative 500-cGy dose of cobalt60 irradiation. Thirty-six male Wistar rats were divided into two equal groups: control (group A), and irradiation group (group B). Group B received a single 500-cGy dose of irradiation, and a rectal resection and end-to-end anastomosis was performed in both groups on the 7th day after irradiation. Parameters of the healing process included bursting pressure and collagen content on the 5th, 7th, and 14th days after surgery. In the irradiation group, the mean bursting pressure on the 5th, 7th, and 14th days was 116, 218, and 273 mmHg, respectively. The collagen content assessed by histomorphometry was 9.0, 20.8, and 32%, respectively. In contrast, the control group had a mean bursting pressure of 175, 225 and 263 mmHg, and a collagen content of 17.8, 28.1, and 32.1%, respectively. The adverse effect of irradiation on healing was detectable only on the 5th postoperative day, as demonstrated by lower bursting pressure (P < 0.013) and collagen content (P < 0.008). However, there was no failure of anastomotic healing such as leakage or dehiscence due to irradiation. We conclude that a single preoperative 500-cGy dose of irradiation delays the healing of rectal anastomosis in rats.
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Anastomotic dehiscence is the most severe complication of colorectal surgery. Metalloproteinases (MMPs) and interleukins (ILs) can be used to analyze the healing process of anastomosis. To evaluate the effects of bromopride on MMP and cytokine gene expression in left colonic anastomoses in rats with or without induced abdominal sepsis, 80 rats were divided into two groups for euthanasia on the third or seventh postoperative day (POD). They were then divided into subgroups of 20 rats for sepsis induction or not, and then into subgroups of 10 rats for administration of bromopride or saline. Left colonic anastomosis was performed and abdominal sepsis was induced by cecal ligation and puncture. A colonic segment containing the anastomosis was removed for analysis of gene expression of MMP-1α, MMP-8, MMP-13, IL-β, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). On the third POD, bromopride was associated with increased MMP-1α, MMP-13, IL-6, IFN-γ, and IL-10 gene expression. On the seventh POD, all MMP transcripts became negatively modulated and all IL transcripts became positively modulated. In the presence of sepsis, bromopride administration increased MMP-8 and IFN-γ gene expression and decreased MMP-1, TNF-α, IL-6, and IL-10 gene expression on the third POD. On the seventh POD, we observed increased expression of MMP-13 and all cytokines, except for TNF-α. In conclusion, bromopride interferes with MMP and IL gene expression during anastomotic healing. Further studies are needed to correlate these changes with the healing process.
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Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs. Eighteen healthy crossbred adult dogs of both sexes weighing between 18 and 20 kg were used and divided into three groups of six: group I, PA section and reanastomosis; group II, PA resection and reconstruction with LyoPA allograft; group III, PA resection and reconstruction with CryoPA allograft. Dogs were evaluated 4 weeks after surgery, and the status of the graft and vascular anastomosis were examined macroscopically and microscopically. No clinical, radiologic, or blood-gas abnormalities were observed during the study. The mean pulmonary artery pressure (MPAP) in group III increased significantly at the end of the study compared with baseline (P=0.02) and final [P=0.007, two-way repeat-measures analysis of variance (RM ANOVA)] values. Pulmonary vascular resistance of groups II and III increased immediately after reperfusion and also at the end of the study compared to baseline. The increase shown by group III vs group I was significant only if compared with after surgery and study end (P=0.016 and P=0.005, respectively, two-way RM ANOVA). Microscopically, permeability was reduced by ≤75% in group III. In conclusion, substitution of PAs with LyoPA grafts is technically feasible and clinically promising.
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The ecological and evolutionary economics of Georgescu-Roegen. The main argument of this paper is that Georgescu-Roegen's contributions represent a major disruption with economics' pre-analytic vision. He rejected at the same time both the closed and circular view of the economy and the mechanic analogies that oriented economics in the past century. Even though his influence has been felt mainly in the field of ecological economics, his epistemological contributions represent a major challenge to equilibrium thinking. Nowadays, treating economic systems as complex and evolutionary systems is becoming not only acceptable, but also a trend in the way political economy is made. We defend that Georgescu-Roegen's disruption represents a scientific revolution in economics, in the sense attributed by Kuhn.
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Työn ensimmäisenä tavoitteena oli parantaa Abloy Oy:n tietämystä yrityksen tarjoamien mekaanisten ja mekatronisten tuotteiden ympäristönäkökohdista ja -vaikutuksista. Työn toisena tavoitteena oli selvittää, voidaanko Abloy Oy:n mekaanisten ja mekatronisten tuotteiden elinkaaren aikaisten ympäristönäkökohtien ja -vaikutusten arviointia kehittää osana nykyistä tuotekehitysprosessia. Tuotteiden ympäristönäkökohtia käsiteltiin kestävän kehityksen, yritysvastuun, ympäristöstrategian ja yksittäisen tuotteen osalta. Ympäristöstrategioiden pohjalta kehitettiin toimintamalleja. Toimintamalleilla kuvataan, mitä toimenpiteitä yrityksen tulisi tehdä, jotta tietty ympäristöstrategian taso saavutetaan. Työn tulos on, että kehitetyillä toimintamalleilla on potentiaalia kehittää Abloy Oy:n mekaanisten ja mekatronisten tuotteiden elinkaaren aikaisten ympäristönäkökohtien ja -vaikutusten arviointia osana nykyistä tuotekehitysprosessimallia.
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Surface fibrils (fimbriae) have been observed on fungi from every major group. Fimbriae are thought to be involved in the following cell to cell interactions: conjugation, flocculation and adhesion. Several higher fungi exibit two other types of interactions: hyphal fusion (anastomosis) and clamp connection formation. As a prelude to examining the role of fimbriae in these processes, the fimbriae of two fungi that undergo these fusion events were examined. Electron microscopy studies revealed that Coprinus cinereus and Schizophyllum commune are fimbriated. C. cinereus fimbriae were 5 nm in diameter and 0.5 to 20 11m in length. Fimbriae of C. cinereus oidia were more numerous and longer than those of the hyphal stage. S. commune fimbriae were also 5 nm in diameter, but were only 0.5 to 2 11m in length. There was an unequal distribution of fimbriae on the hyphal surfaces of S. commune . Fimbriae were sparsely distributed over the entire hyphal surface, with higher densities of fibrils present on the side growths of the hyphae found in the older sections of the mycelium. Antiserum raised against Ustilago violacea fimbrial protein (AU) crossreacted strongly with 37 and 39 kd C. cinereus mycelial proteins. In contrast, AU bound very weakly to 89 and 92 kd S. commune mycelial proteins. Since AU cross-reacted poorly with S. commune fimbrial proteins, it was impossible to further characterize the fimbriae of this specIes. The 37 and 39 kd C. cinereus proteins, were isolated by electroelution and were shown to be able to form fibrils the same diameter as oidial fimbriae. The 37 kd protein was shown to be composed of several proteins with isoelectric points ranging from pH 6.1 to 7.63. Furthermore, the 37 kd protein was found to be multimeric, while the 39 kd protein was not. These results strongly suggested that the 37 kd protein is the structural fimbrial protein of C. cine reus . Finally, a series of experiments were designed to determine whether fimbriae are required for conjugation in U. violacea Conjugation was inhibited significantly with AU, but not with pre-immune serum or AU preincubated with purified fimbrial protein. Thus, it was concluded that fimbriae play a central role in mating in this organism.
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L'encéphalopathie hépatique (EH) est un syndrome neuropsychiatrique dû à une dysfonction hépatique où l'ammoniaque est un facteur central. Il a déjà été rapporté que l’intoxication aiguë d'ammoniaque induise le stress oxydatif/nitrosatif. La présente étude cible à évaluer le rôle du stress oxydatif/nitrosatif dans 2 modèles de l’EH chronique : (1) l’anastomose portocave (PCA) et (2) la ligation de la voie biliaire (BDL). Ces 2 modèles sont caractérisés par une hyperammoniémie et une augmentation d’ammoniaque centrale, cependant l’œdème cérébral est trouvé seulement chez les rats BDL. Des marqueurs du stress oxydatif/nitrosatif ont été évaluées dans le plasma et cortex frontal. Un stress nitrosatif central a été observé chez les rats PCA; tandis qu’un stress oxydatif/nitrosatif systémique a été démontré seulement chez les rats BDL. Ces résultats suggèrent (1) que l’hyperammoniémie chronique n’induise pas le stress oxydatif/nitrosatif systémique et (2) qu’un synergisme existe entre l’ammoniaque et le stress oxydatif/nitrosatif, en association avec l’œdème cérébral.
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L’œdème cérébral est une complication associée à l’encéphalopathie hépatique (EH) lors d’une insuffisance hépatique chronique (cirrhose du foie). Présentement, l’origine de sa pathogenèse, vasogénique (rupture de la barrière hémato-encéphalique (BHE)) ou cytotoxique (prise anormale d’ions), n’a pas encore été déterminée. Il a été démontré que le co-transporteur Na-K-Cl (NKCC1) du côté luminal des microvaisseaux sanguins cérébraux (CMV) joue un rôle dans le développement de l’œdème cérébral dans des modèles d’ischémie où la bumetanide, un inhibiteur de NKCC, atténue l’œdème cérébral. Deux modèles d’EH ont été utilisés pour cette étude i) la ligature de la voie biliaire (BDL) qui présente l’hyperammoniémie chronique, l’œdème cérébral et le stress oxydatif systémique ; ii) l’anastomose portocave (PCA) qui présente de l’hyperammoniémie chronique seulement. Les buts du projet étaient de: i) définir l’origine du développement de l’œdème chez les rats BDL en étudiant l’extravasation de macromolécules, les jonctions serrées et l’activation des métalloprotéinases matricielles de la BHE; ii) observer les effets de l’hyperammoniémie chronique indépendamment sur la BHE chez les rats PCA; iii) évaluer le rôle de l’hyperammoniémie et du stress oxydatif et iv) étudier le rôle du NKCC1 dans les CMV dans la pathogenèse de l’œdème cérébral. Les résultats du projet démontrent que l’œdème est d’origine cytotoxique chez les rats BDL et que l’intégrité de la BHE est conservée chez les rats PCA malgré l’hyperammoniémie. L’expression génique du NKCC1 est associée à l’œdème mais pas son expression protéique et sa phosphorylation. Enfin, l’étude démontre que l’hyperammoniémie et le stress oxydatif indépendant ne jouent pas un rôle dans la pathogenèse de l’œdème mais suggère qu’ils y aient un effet synergique.