975 resultados para Zero Effective Length Factor


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Context: Jansen's metaphyseal chondrodysplasia (JMC) is a rare autosomal dominant disorder caused by activating mutations in the PTH 1 receptor (PTH1R; PTH/PTHrP receptor), leading to chronic hypercalcemia and hypercalciuria. Hypophosphatemia is also a hallmark of JMC, and recently, increased fibroblast growth factor 23 (FGF23) levels have been reported in this syndrome. Hypercalcemia has been associated with increased cardiovascular risk; however, cardiovascular disease has not been extensively investigated in JMC patients. Objective: The aim of the study was to describe the long-term follow-up of a JMC patient with regard to the management of hypercalciuria, the evaluation of FGF23 levels under bisphosphonate treatment, and the investigation of cardiovascular repercussion of chronic hypercalcemia. Results: The diagnosis of JCM was confirmed by molecular analysis (p.H223R mutation in PTH1R). The patient was followed from 5 to 27 yr of age. Asymptomatic nephrolithiasis was diagnosed at 18 yr of age, prompting pharmacological management of hypercalciuria. Treatment with alendronate reduced hypercalciuria; however, normocalciuria was only obtained with the association of thiazide diuretic. Serum FGF23 levels, measured under alendronate treatment, were repeatedly within the normal range. Subclinical cardiovascular disease was investigated when the patient was 26 yr old, after 19 yr of sustained mild hypercalcemia; carotid and vertebral artery ultrasonography was normal, as well as coronary computed tomography angiography (calcium score = 0). Conclusion: The long-term follow-up of our JMC patient has provided insight on therapeutic strategies to control hypercalciuria, on the potential effects of alendronate on FGF23 levels, and on the lack of detectable cardiovascular disease at young adulthood after prolonged exposure to hypercalcemia. (J Clin Endocrinol Metab 97: 1098-1103, 2012)

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Abstract Background Allogeneic red blood cell (RBC) transfusion has been proposed as a negative indicator of quality in cardiac surgery. Hospital length of stay (LOS) may be a surrogate of poor outcome in transfused patients. Methods Data from 502 patients included in Transfusion Requirements After Cardiac Surgery (TRACS) study were analyzed to assess the relationship between RBC transfusion and hospital LOS in patients undergoing cardiac surgery and enrolled in the TRACS study. Results According to the status of RBC transfusion, patients were categorized into the following three groups: 1) 199 patients (40%) who did not receive RBC, 2) 241 patients (48%) who received 3 RBC units or fewer (low transfusion requirement group), and 3) 62 patients (12%) who received more than 3 RBC units (high transfusion requirement group). In a multivariable Cox proportional hazards model, the following factors were predictive of a prolonged hospital length of stay: age higher than 65 years, EuroSCORE, valvular surgery, combined procedure, LVEF lower than 40% and RBC transfusion of > 3 units. Conclusion RBC transfusion is an independent risk factor for increased LOS in patients undergoing cardiac surgery. This finding highlights the adequacy of a restrictive transfusion therapy in patients undergoing cardiac surgery. Trial registration Clinicaltrials.gov identifier: http://NCT01021631.

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Hereditary hair length variability in mice and dogs is caused by mutations within the fibroblast growth factor 5 (FGF5) gene. The aim of this study was to evaluate the feline FGF5 orthologue as a functional candidate gene for the long hair phenotype in cats, which is recessive to short hair. We amplified the feline FGF5 cDNA and characterised two alternatively spliced transcripts by RT-PCR. Comparative cDNA and genomic DNA sequencing of long- and short-haired cats revealed four non-synonymous polymorphisms in the FGF5 coding sequence. A missense mutation (AM412646:c.194C>A) was found in the homozygous state in 25 long-haired Somali, Persian, Maine Coon, Ragdoll and crossbred cats. Fifty-five short-haired cats had zero or one copy of this allele. Additionally, we found perfect co-segregation of the c.194C>A mutation within two independent pedigrees segregating for hair length. A second FGF5 exon 1 missense mutation (AM412646:c.182T>A) was found exclusively in long-haired Norwegian Forest cats. The c.182T>A mutation probably represents a second FGF5 mutation responsible for long hair in cats. In addition to the c.194C>A mutation, a frameshift mutation (AM412646:c.474delT) was found with a high frequency in the long-haired Maine Coon breed. Finally, a missense mutation (AM412646:c.475A>C) was also associated with the long-haired phenotype in some breeds. However, as one short-haired cat was homozygous for this polymorphism, it is unlikely that it has a functional role in the determination of hair length.

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This dissertation presents an effective quasi one-dimensional (1-D) computational simulation tool and a full two-dimensional (2-D) computational simulation methodology for steady annular/stratified internal condensing flows of pure vapor. These simulation tools are used to investigate internal condensing flows in both gravity as well as shear driven environments. Through accurate numerical simulations of the full two dimensional governing equations, results for laminar/laminar condensing flows inside mm-scale ducts are presented. The methodology has been developed using MATLAB/COMSOL platform and is currently capable of simulating film-wise condensation for steady (and unsteady flows). Moreover, a novel 1-D solution technique, capable of simulating condensing flows inside rectangular and circular ducts with different thermal boundary conditions is also presented. The results obtained from the 2-D scientific tool and 1-D engineering tool, are validated and synthesized with experimental results for gravity dominated flows inside vertical tube and inclined channel; and, also, for shear/pressure driven flows inside horizontal channels. Furthermore, these simulation tools are employed to demonstrate key differences of physics between gravity dominated and shear/pressure driven flows. A transition map that distinguishes shear driven, gravity driven, and “mixed” driven flow zones within the non-dimensional parameter space that govern these duct flows is presented along with the film thickness and heat transfer correlations that are valid in these zones. It has also been shown that internal condensing flows in a micro-meter scale duct experiences shear driven flow, even in different gravitational environments. The full 2-D steady computational tool has been employed to investigate the length of annularity. The result for a shear driven flow in a horizontal channel shows that in absence of any noise or pressure fluctuation at the inlet, the onset of non-annularity is partly due to insufficient shear at the liquid-vapor interface. This result is being further corroborated/investigated by R. R. Naik with the help of the unsteady simulation tool. The condensing flow results and flow physics understanding developed through these simulation tools will be instrumental in reliable design of modern micro-scale and spacebased thermal systems.

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Purpose

The objective of our study was to test a new approach to approximating organ dose by using the effective energy of the combined 80kV/140kV beam used in fast kV switch dual-energy (DE) computed tomography (CT). The two primary focuses of the study were to first validate experimentally the dose equivalency between MOSFET and ion chamber (as a gold standard) in a fast kV switch DE environment, and secondly to estimate effective dose (ED) of DECT scans using MOSFET detectors and an anthropomorphic phantom.

Materials and Methods

A GE Discovery 750 CT scanner was employed using a fast-kV switch abdomen/pelvis protocol alternating between 80 kV and 140 kV. The specific aims of our study were to (1) Characterize the effective energy of the dual energy environment; (2) Estimate the f-factor for soft tissue; (3) Calibrate the MOSFET detectors using a beam with effective energy equal to the combined DE environment; (4) Validate our calibration by using MOSFET detectors and ion chamber to measure dose at the center of a CTDI body phantom; (5) Measure ED for an abdomen/pelvis scan using an anthropomorphic phantom and applying ICRP 103 tissue weighting factors; and (6) Estimate ED using AAPM Dose Length Product (DLP) method. The effective energy of the combined beam was calculated by measuring dose with an ion chamber under varying thicknesses of aluminum to determine half-value layer (HVL).

Results

The effective energy of the combined dual-energy beams was found to be 42.8 kV. After calibration, tissue dose in the center of the CTDI body phantom was measured at 1.71 ± 0.01 cGy using an ion chamber, and 1.73±0.04 and 1.69±0.09 using two separate MOSFET detectors. This result showed a -0.93% and 1.40 % difference, respectively, between ion chamber and MOSFET. ED from the dual-energy scan was calculated as 16.49 ± 0.04 mSv by the MOSFET method and 14.62 mSv by the DLP method.

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Experiments with ultracold atoms in optical lattice have become a versatile testing ground to study diverse quantum many-body Hamiltonians. A single-band Bose-Hubbard (BH) Hamiltonian was first proposed to describe these systems in 1998 and its associated quantum phase-transition was subsequently observed in 2002. Over the years, there has been a rapid progress in experimental realizations of more complex lattice geometries, leading to more exotic BH Hamiltonians with contributions from excited bands, and modified tunneling and interaction energies. There has also been interesting theoretical insights and experimental studies on “un- conventional” Bose-Einstein condensates in optical lattices and predictions of rich orbital physics in higher bands. In this thesis, I present our results on several multi- band BH models and emergent quantum phenomena. In particular, I study optical lattices with two local minima per unit cell and show that the low energy states of a multi-band BH Hamiltonian with only pairwise interactions is equivalent to an effec- tive single-band Hamiltonian with strong three-body interactions. I also propose a second method to create three-body interactions in ultracold gases of bosonic atoms in a optical lattice. In this case, this is achieved by a careful cancellation of two contributions in the pair-wise interaction between the atoms, one proportional to the zero-energy scattering length and a second proportional to the effective range. I subsequently study the physics of Bose-Einstein condensation in the second band of a double-well 2D lattice and show that the collision aided decay rate of the con- densate to the ground band is smaller than the tunneling rate between neighboring unit cells. Finally, I propose a numerical method using the discrete variable repre- sentation for constructing real-valued Wannier functions localized in a unit cell for optical lattices. The developed numerical method is general and can be applied to a wide array of optical lattice geometries in one, two or three dimensions.

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A determinação da relação do peso úmido (WT) pela largura cefalotorácica (CW) do caranguejo U. cordatus e a análise da dinâmica temporo-sazonal do fator de condição foram realizadas com machos e fêmeas coletados mensalmente no período de 1998/2000, em Iguape (SP). A relação WT/CW foi determinada por análise de regressão, enquanto o fator de condição foi determinado individualmente para cada animal, bem como pela média mensal e sazonal para cada sexo. A relação WT/CW evidenciou um crescimento isométrico nos machos e alométrico negativo nas fêmeas, indicando que os machos atingem um peso corpóreo superior ao das fêmeas para um mesmo tamanho de referência. Tal fato está associado ao maior crescimento e peso dos quelípodos do macho. As médias do fator de condição das fêmeas foram maiores que as dos machos. Os menores valores do fator de condição ocorreram durante a primavera e verão, atingindo os maiores níveis durante o outono e inverno.

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The aim of this study was to evaluate by photoelastic analysis stress distribution on short and long implants of two dental implant systems with 2-unit implant-supported fixed partial prostheses of 8 mm and 13 mm heights. Sixteen photoelastic models were divided into 4 groups: I: long implant (5 × 11 mm) (Neodent), II: long implant (5 × 11 mm) (Bicon), III: short implant (5 × 6 mm) (Neodent), and IV: short implants (5 × 6 mm) (Bicon). The models were positioned in a circular polariscope associated with a cell load and static axial (0.5 Kgf) and nonaxial load (15°, 0.5 Kgf) were applied to each group for both prosthetic crown heights. Three-way ANOVA was used to compare the factors implant length, crown height, and implant system (α = 0.05). The results showed that implant length was a statistically significant factor for both axial and nonaxial loading. The 13 mm prosthetic crown did not result in statistically significant differences in stress distribution between the implant systems and implant lengths studied, regardless of load type (P > 0.05). It can be concluded that short implants showed higher stress levels than long implants. Implant system and length was not relevant factors when prosthetic crown height were increased.

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Objective: To verify the relationship between maxillary and mandibular effective lengths and dental crowding in patients with Class II malocclusions. Materials and Methods: The sample comprised 80 orthodontic patients with complete Class II malocclusions in the permanent dentition (47 male, 33 female) who were divided into two groups according to the amount of mandibular tooth-arch size discrepancy. The maxillary and mandibular effective lengths (Co-A and Co-Gn) and tooth-arch size discrepancies were measured on the initial cephalograms and dental casts, respectively. Intergroup comparisons of apical base lengths were performed with independent t-tests. Correlation between base length and dental crowding was examined by means of Pearson's correlation coefficient (P < .05). Results: Patients with Class II malocclusion and moderate to severe crowding had significantly smaller maxillary and mandibular effective lengths than subjects with the same malocclusion and slight mandibular crowding. A weak inverse correlation was also found between maxillary and mandibular effective lengths and the severity of dental crowding. Conclusion: Decreased maxillary and mandibular effective lengths constitute an important factor associated with dental crowding in patients with complete Class II malocclusion. (Angle Orthod. 2011;81:217-221.)