990 resultados para SMOOTH CONJUGACY
Resumo:
A welfare analysis of unemployment insurance (UI) is performed in a generalequilibrium job search model. Finitely-lived, risk-averse workers smooth consumption over time by accumulating assets, choose search effort whenunemployed, and suffer disutility from work. Firms hire workers, purchasecapital, and pay taxes to finance worker benefits; their equity is the assetaccumulated by workers. A matching function relates unemployment, hiringexpenditure, and search effort to the formation of jobs. The model is calibrated to US data; the parameters relating job search effort to the probability of job finding are chosen to match microeconomic studies ofunemployment spells. Under logarithmic utility, numerical simulation shows rather small welfaregains from UI. Even without UI, workers smooth consumption effectivelythrough asset accumulation. Greater risk aversion leads to substantiallylarger welfare gains from UI; however, even in this case much of its welfareimpact is due not to consumption smoothing effects, but rather to decreased work disutility, or to a variety of externalities.
Resumo:
Background: Bacteria form biofilms on the surface of orthopaedic devices, causing persistent infections. Monitoring biofilm formation on bone grafts and bone substitutes is challenging due to heterogeneous surface characteristics. We analyzed various bone grafts and bone substitutes regarding their propensity for in-vitro biofilm formation caused by S. aureus and S. epidermidis. Methods: Beta-tricalciumphosphate (b-TCP, ChronOsTM), processed human spongiosa (TutoplastTM) and PMMA (PalacosTM) were investigated. PE was added as a growth control. As test strains S. aureus (ATCC 29213) and S. epidermidis RP62A (ATCC 35984) were used. Test materials were incubated with 105 cfu/ml. After 24 h, test materials were removed and washed, followed by a standardised sonication protocol. The resulting sonication fluid was plated and bacterial counts were enumerated and expressed as cfu/sample. Sonicated samples were transferred to a microcalorimeter (TA Instrument) and heat flow monitored over a 24 h period with a precision of 0.0001°C and a sensitiviy of 200 μW. Experiments were performed in triplicates to calculate the mean ± SD. One-way ANOVA analysis was used for statistical analysis. Results: Bacterial counts (log10 cfu/sample) were highest on b-TCP (S. aureus 7.67 ± 0.17; S. epidermidis 8.14 ± 0.05) while bacterial density (log10 cfu/surface) was highest on PMMA (S. aureus 6.12 ± 0.2, S. epidermidis 7.65 ± 0.13). Detection time for S. aureus biofilms was shorter for the porous materials (b-TCP and Tutoplast, p <0.001) compared to the smooth materials (PMMA and PE) with no differences between b-TCP and TutoplastTM (p >0.05) or PMMA and PE (p >0.05). In contrast, for S. epidermidis biofilms the detection time was different (p <0.001) between all materials except between Tutoplast and PE (p >0.05). Conclusion: Our results demonstrate biofilm formation with both strains on all tested materials. Microcalorimetry was able to detect quantitatively the amount of biofilm. Further studies are needed to see whether calorimetry is a suitable tool also to monitor approaches to prevent and treat infections associated with bone grafts and bone substitutes.
Resumo:
OBJECTIVE: To evaluate the results of Muller's muscle-conjunctival resection for correction of blepharoptosis and to discuss the advantages of this procedure. METHODS: 38 patients (39 eyelids) were submitted to Muller's muscle-conjunctival resection. Blepharoptosis varied from 1.0 mm to 3.0 mm (mean: 2.0 mm). The amount of eyelid elevation produced by phenylephrine guided the amount of tissue to be resected. RESULT: 33 eyelids (85%) treated with this procedure were cosmetically acceptable. CONCLUSIONS: Muller's muscle-conjunctival resection procedure is a relatively simple technique for blepharoptosis, with good levator function and positive 10% phenylephrine test. The advantages are: preservation of tarsus and predictable results.
Resumo:
The aim of the present study was to investigate to what extent interstitial lung disease (ILD) in common variable immunodeficiency disorder (CVID)-associated granulomatous disease (GD) is similar to pulmonary sarcoidosis 20 patients with CVID/GD were included in a retrospective study conducted by the Groupe Sarcoïdose Francophone. Medical records were centralised. Patients were compared with 60 controls with sarcoidosis. Clinical examination showed more frequent crackles in patients than controls (45% versus 1.7%, respectively; p<0.001). On thoracic computed tomography scans, nodules (often multiple and with smooth margins), air bronchograms and halo signs were more frequent in patients than controls (80% versus 42%, respectively; p=0.004) as well as bronchiectasis (65% versus 23%, respectively; p<0.001). The micronodule distribution was perilymphatic in 100% of controls and in 42% of patients (p<0.001). Bronchoalveolar lavage analysis showed lower T-cell CD4/CD8 ratios in patients than in controls (mean±sd 1.6±1.1 versus 5.3±4, respectively; p<0.01). On pathological analysis, nodules and consolidations corresponded to granulomatous lesions with or without lymphocytic disorders in most cases. Mortality was higher in patients than controls (30% versus 0%, respectively) and resulted from common variable immunodeficiency complications. ILD in CVID/GD presents a specific clinical picture and evolution that are markedly different from those of sarcoidosis.
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Scaffold materials should favor cell attachment and proliferation, and provide designable 3D structures with appropriate mechanical strength. Collagen matrices have proven to be beneficial scaffolds for tissue regeneration. However, apart from small intestinal submucosa, they offer a limited mechanical strength even if crosslinking can enhance their mechanical properties. A more cell-friendly way to increase material strength is to combine synthetic polymer meshes with plastic compressed collagen gels. This work describes the potential of plastic compressed collagen-poly(lactic acid-co-ɛ-caprolactone) (PLAC) hybrids as scaffolds for bladder tissue regeneration. Human bladder smooth muscle and urothelial cells were cultured on and inside collagen-PLAC hybrids in vitro. Scaffolds were analyzed by electron microscopy, histology, immunohistochemistry, and AlamarBlue assay. Both cell types proliferated in and on the hybrid, forming dense cell layers on top after two weeks. Furthermore, hybrids were implanted subcutaneously in the backs of nude mice. Host cell infiltration, scaffold degradation, and the presence of the seeded bladder cells were analyzed. Hybrids showed a lower inflammatory reaction in vivo than PLAC meshes alone, and first signs of polymer degradation were visible at six months. Collagen-PLAC hybrids have potential for bladder tissue regeneration, as they show efficient cell seeding, proliferation, and good mechanical properties.
Resumo:
Proper function of the wall of bladder requires gap junctional communication for coordinating the responses of smooth muscle (SMC) and urothelial cells exposed to urine pressure. In the rat bladder, Cx43 is expressed by SMC and urothelial cells, whereas Cx26 expression is restricted to the epithelium. We used a model of bladder outlet obstruction, in which a ligature is placed around the urethra to increase voiding pressure. Increased fluid pressure was associated with increased Cx43 and Cx26 mRNA expression and with the activation of a signaling cascade including the transcription factor c-Jun, which is a component of the AP-1 complex. The signaling pathway of the c-Jun NH2 terminal kinase (JNK) requires the presence of the scaffold protein Islet-Brain1/c-Jun amino-terminal kinase Interacting Protein-1 (IB1/JIP-1). Under stress conditions resulting from urine retention, we have found a reduced content of IB1/JIP-1 in urothelial cells, which in turn induced a drastic increase of JNK and AP-1 binding activities. The stress-induced activation of JNK was prevented by overexpressing IB1/JIP-1, using a viral gene transfer approach, a condition which also resulted in a decrease in Cx26 mRNA. The data show that: 1) mechanical stress of urothelial cells activates in vivo JNK, as a consequence of a regulated expression of IB1/JIP-1 and 2) that urothelial Cx26 may be directly regulated by the AP-1 complex.
Low-pressure environment and remodelling of the forearm vein in Brescia-Cimino haemodialysis access.
Resumo:
BACKGROUND: The aim of the study was to determine which, and to what extent, haemodynamic parameters contribute to the remodelling of the venous limb of the Brescia-Cimino haemodialysis access. METHODS: The dimensions of the radial artery and the venous limb of the haemodialysis access were measured by an echo-tracking technique. In six ESRD patients undergoing primary arteriovenous fistula (AVF) formation, vessel diameter, wall thickness, blood pressure and blood flow were measured after the operation, and at 1 and 3 months follow-up. The contralateral forearm vessels in their native position served as baseline values for comparison. RESULTS: The diameter of the proximal antecubital vein progressively increased over the study period without reaching significant differences (4430, 5041 and 6620 microm at weeks 1, 4 and 12 respectively), whereas the intima-media thickness remained unchanged. The venous dilatation was associated with a reduction of the mean shear stress that culminated after the operation and progressively returned to normal venous values at 3 months (24.5 vs 10.4 dyne/cm(2), P<0.043). Thus the venous limb of the AVF undergoes eccentric hypertrophy as demonstrated by the increase in wall cross-sectional area (4.42 vs 6.32 mm(2) at week 1 vs week 12, P<0.028). At the time of the operation, the blood pressure in the AVF was 151+/-14/92.4+/-11 mmHg vs 49+/-19/24.5+/-6 mmHg (means+/-SEM) for the radial artery and the venous limb of the vascular access, respectively. One year after the operation the blood pressure in the venous limb had not changed: 42+/-14/25.3+/-7 mmHg (means+/-SEM). Under these conditions, the systolo-diastolic diameter changes observed in the radial artery and the antecubital vein were within a similar range at all time points: 56+/-17 vs 90+/-26 microm (means+/-SEM) at week 12. CONCLUSIONS: The increased circumferential stress resulting from the flow-mediated dilatation rather than the elevation of blood pressure appears to represent the main contributing factor to the eccentric hypertrophy of the venous limb of Brescia-Cimino haemodialysis access.
Resumo:
PURPOSE: To report a series of patients with cerebellar dysfunction and altered vision during motion, and to quantify their visual impairment in motion with a simple clinical test. METHODS: Twenty consecutive patients suffering from cerebellar dysfunction and altered vision during motion were examined between 1994 and 2007. A control group consisted of 20 age- and sex-matched healthy people. All patients had a full neuro-ophthalmic examination. Near visual acuity (NVA) was measured at rest (static NVA) and during chair rotation (dynamic NVA). Distance visual acuity (DVA) was measured at rest (static DVA) and during rotation of the patient's head (dynamic DVA). RESULTS: Only four of the 20 patients reported altered vision during motion spontaneously. The remaining 16 patients admitted this unusual visual disturbance only when asked specifically. All patients exhibited abnormal eye movements, including saccadic smooth pursuit (20/20), dysmetric saccades (15/20), nystagmus (19/20) and impaired suppression of vestibulo-ocular reflex (VOR) (20/20). During rotation of the examination chair (dynamic NVA), the drop in NVA averaged 5.6 lines (range 1-10 lines). During rotation of the patient's head (dynamic DVA), the drop in DVA averaged only 2.5 lines (range 0-10 lines). For the control group, there was no significant drop in NVA under dynamic conditions. CONCLUSION: Patients with cerebellar dysfunction rarely complain spontaneously of altered vision during motion. However, specific questioning may bring up this unusual symptom. The use of a simple clinical test, consisting of NVA measurement during rotation of the examination chair (dynamic NVA), allows practitioners to quantify the level of visual impairment in patients presenting altered VOR modulation.
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Atlas registration is a recognized paradigm for the automatic segmentation of normal MR brain images. Unfortunately, atlas-based segmentation has been of limited use in presence of large space-occupying lesions. In fact, brain deformations induced by such lesions are added to normal anatomical variability and they may dramatically shift and deform anatomically or functionally important brain structures. In this work, we chose to focus on the problem of inter-subject registration of MR images with large tumors, inducing a significant shift of surrounding anatomical structures. First, a brief survey of the existing methods that have been proposed to deal with this problem is presented. This introduces the discussion about the requirements and desirable properties that we consider necessary to be fulfilled by a registration method in this context: To have a dense and smooth deformation field and a model of lesion growth, to model different deformability for some structures, to introduce more prior knowledge, and to use voxel-based features with a similarity measure robust to intensity differences. In a second part of this work, we propose a new approach that overcomes some of the main limitations of the existing techniques while complying with most of the desired requirements above. Our algorithm combines the mathematical framework for computing a variational flow proposed by Hermosillo et al. [G. Hermosillo, C. Chefd'Hotel, O. Faugeras, A variational approach to multi-modal image matching, Tech. Rep., INRIA (February 2001).] with the radial lesion growth pattern presented by Bach et al. [M. Bach Cuadra, C. Pollo, A. Bardera, O. Cuisenaire, J.-G. Villemure, J.-Ph. Thiran, Atlas-based segmentation of pathological MR brain images using a model of lesion growth, IEEE Trans. Med. Imag. 23 (10) (2004) 1301-1314.]. Results on patients with a meningioma are visually assessed and compared to those obtained with the most similar method from the state-of-the-art.
Resumo:
Spatial-temporal regulation of bone morphogenetic protein (BMP) and Wnt activity is essential for normal cardiovascular development, and altered activity of these growth factors causes maldevelopment of the cardiac outflow tract and great arteries. In the present study, we show that SOST, a Dan family member reported to antagonize BMP and Wnt activity, is expressed within the medial vessel wall of the great arteries containing smooth muscle cells. The ascending aorta, aortic arch, brachiocephalic artery, common carotids, and pulmonary trunk were all associated with SOST expressing smooth muscle cells, while the heart itself, including the valves, and more distal arteries, that is, pulmonary arteries, subclavian arteries, and descending aorta, were negative. SOST was expressed from embryonic day 15.5 up to the neonatal period. SOST expression, however, did not correspond with inhibition of Smad-dependent BMP activity or beta-catenin-dependent Wnt activity in the great arteries. Activity of both signaling pathways was already down-regulated before induction of SOST expression.
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In vitro studies have shown that stimulation of alpha1-adrenoceptors (ARs) directly induces proliferation, hypertrophy, and migration of arterial smooth muscle cells and adventitial fibroblasts. In vivo studies confirmed these findings and showed that catecholamine trophic activity becomes excessive after experimental balloon injury and contributes to neointimal growth, adventitial thickening, and lumen loss. However, past studies have been limited by selectivity of pharmacological agents. The aim of this study, in which mice devoid of norepinephrine and epinephrine synthesis [dopamine beta-hydroxylase (DBH-/-)] or deficient in alpha1-AR subtypes expressed in murine carotid (alpha1B-AR-/- and alpha1D-AR-/-) were used, was to test the hypothesis that catecholamines contribute to wall hypertrophy after injury. At 3 wk after injury of wild-type mice, lumen area and carotid circumference increased significantly, and hypertrophy of media and adventitia was in excess of that needed to restore circumferential wall stress to normal. In DBH-/- and alpha1B-AR-/- mice, increases in lumen area, circumference, and hypertrophy of the media and adventitia were reduced by 50-91%, resulting in restoration of wall tension to nearly normal (DBH-/-) or normal (alpha1B-AR-/-). In contrast, in alpha1D-AR-/- mice, increases in lumen area, circumference, and wall hypertrophy were unaffected and wall thickening remained in excess of that required to return tension to normal. When examined 5 days after injury, proliferation and leukocyte infiltration were inhibited in DBH-/- mice. These studies suggest that the trophic effects of catecholamines are mediated primarily by alpha1B-ARs in mouse carotid and contribute to hypertrophic growth after vascular injury.
Resumo:
The annual meeting of the French Ion Channels Society, held on the Mediterranean coast of France, is aimed at gathering the international scientific community working on various aspects of ion channels. In this report of the 19th edition of the meeting, held in September 2008, we summarize selected symposia on aspects of the ion channel field from fundamental to clinical research. The meeting is an opportunity for leading investigators as well as young researchers to present and discuss their recent advances and future challenges in the ion channel field.
Resumo:
The structure of the shield of curly overhairs was studied in 22 genera of shrews, using scanning electron microscopy. The cross section of the shield is quadriconcave with two sides showing particular scale patterns or a relief which can be grouped into 4 morphological types: 1) a smooth type with, at most, shallow U-shaped notches; 2) a type with uniserial, V-shaped tiled notches; 3) a type with a groove and irregular notches; 4) a type with a deep ridged groove. Myosorex, which occupies a basal phyletic position, shows type 3. This type is therefore interpreted as an ancestral character state. It is found also in Feroculus and in some Sylvisorex. In the Crocidurinae, this type evolved into type 2 (Scutisorex and some Indomalayan Crocidura), and finally into type 1 (Suncus and most Crocidura). In the Soricinae, it evolved into type 4, which is common to all genera except Megasorex and Notiosorex. These two genera possess type 1 which is interpreted as being a synapomorphous character of these genera. The regression of the complex structure under dry climatic conditions supports the hypothesis that the function of the grooved form of hair is water repulsion.
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beta-Adrenergic agonists are important regulators of perinatal pulmonary circulation. They cause vasodilation primarily via the adenyl cyclase-adenosine 3',5'-cyclic monophosphate (cAMP) pathway. We examined the responses of isolated fourth-generation pulmonary veins of term fetal (145 +/- 2 days gestation) and newborn (10 +/- 1 days) lambs to isoproterenol, a beta-adrenergic agonist. In vessels preconstricted with U-46619 (a thromboxane A2 analog), isoproterenol induced greater relaxation in pulmonary veins of newborn lambs than in those of fetal lambs. The relaxation was eliminated by propranolol, a beta-adrenergic antagonist. Forskolin, an activator of adenyl cyclase, also caused greater relaxation of veins of newborn than those of fetal lambs. 8-Bromoadenosine 3',5'-cyclic monophosphate, a cell membrane-permeable analog of cAMP, induced a similar relaxation of all vessels. Biochemical studies show that isoproterenol and forskolin induced a greater increase in cAMP content and in adenyl cyclase activity of pulmonary veins in the newborn than in the fetal lamb. These results demonstrate that beta-adrenergic-agonist-mediated relaxation of pulmonary veins increases with maturation. An increase in the activity of adenyl cyclase may contribute to the change.
Resumo:
En la societat en què vivim cada vegada agafen més importància les pàgines web, ja que és una eina d’informació molt útil i ràpida de consultar. Per això, no s’entén que una activitat empresarial sigui del tipus que sigui, no tingui representació a la xarxa. No és necessari que l’activitat en qüestió hagi de vendre productes a través d’Internet, sinó que simplement aquesta representació pot ajudar a donar a conèixer l’empresa i a ampliar la cartera de clients. De la mateixa manera, els dispositius mòbils també s’estan convertint en una eina important en la societat d’avui en dia i una bona aplicació pot aportar-te un avantatge en moltes de les feines diàries de les persones. D’aquestes idees sorgeix el projecte de fer la web i l’aplicació pel centre de fisioteràpia Fisioripoll. La web serviria per tenir un lloc a la xarxa on donar-se a conèixer i poder captar nous clients, i l’aplicació funcionaria com a eina pel propi centre, seria una espècie d’agenda electrònica per saber les hores que tens reservades els pròxims dies. Per aconseguir un bon funcionament de la web, s’ha demanat que la pàgina sigui administrable en els seus continguts. És a dir, que els propis gestors del centre puguin canviar els texts, les imatges dels diferents apartats i gestionar les reserves dels clients. En canvi, l’aplicació serà només una eina de consulta i no s’hauria de gestionar res. Per tal de dur a terme aquesta web s’ha tingut en compte utilitzar eines de programació de distribució lliure com és el llenguatge PHP, la base de dades MySQL, jQuery, el framework Phonegap per tal de poder construir una web i una aplicació amb cost de programari nul.