1,792 research outputs found
Transport coefficients at Metastable Densities from models of Generalized Hydrodynamics
In the present work we compute the enhancement in the long time transport
coefficients due to correlated motion of fluid particles at high density. The
fully wave vecor dependent extended mode coupling model is studied with the
inclusion of an additional slow variable of the defect density for the
amorphous system.
We use the extremely slow relaxation of the density correlation function
observed in the light scattering experiments on colloids to estimate the input
parameters for the model The ratio of long time to short time diffusion
coefficient is studied around the the peak of the structure factor.Comment: 17 pages, 8 figure
Temperature dependence of the Power law exponent of relaxation in a supercooled Liquid
The dynamics of Lennard-Jones fluid is studied through extended mode coupling
theory (MCT) with the inclusion of the slow mode of defect density. Inclusion
of defect density facilitates the liquid like state for temperatures much lower
than predicted from ideal MCT. From the present model the temperature
dependence of the power law exponent is obtained at a {\em constant pressure}.
We have also computed the wave number dependence of the power law exponent.Comment: 10 pages, 6 figure
Fragility and Boson Peak formation in a Supercooled Liquid
We analyze results for the Boson Peak from the neutron time of flight
spectroscopy data on Ge-As-Se, and Raman spectra data on m-TCP and OTP, using a
recent mode coupling model that takes into account the coupling of density
fluctuations with vibrational modes in presence of defects in the supercooled
state.
From the experimental results for different materials we observe that for
more fragile systems characterized by increasing fragility parameter m, a
slower relaxation of the defect-density correlation is needed to give rise to
the observed peak in the spectra.Comment: 6 pages, 5 figure
Caffey disease – A rare case report.
8 month old male infant with localized swelling of the thigh, fever and irritability
MUCOCELE OF THE APPENDIX WITH PERFORATION.
45 year old gentleman, presented to the Emergency Department with right iliac fossa pain & fever
CONGENITAL LOBAR OVERINFLATION
1 year old girl with history of recurrent respiratory infections associated with wheeze
Diffusion Tensor Imaging as a novel technique in early detection of cervical spondylotic myelopathy
Introduction: Diffusion tensor imaging (DTI) is an advanced MR imaging technique which helps in early detection of cervical spondylotic myelopathy (CSM). Decompressive surgery performed during early stages of the disease was reported to be more successful when compared with later stages. Aim: To evaluate the usefulness of diffusion tensor imaging (DTI) in early stages of cervical spondylotic myelopathy (CSM) and to aid in better surgical outcome. Materials and methods: This prospective observational study included 25 patients with clinical diagnosis of cervical spondylotic myelopathy who underwent routine MRI of the cervical spine. Conventional MRI sequences along with diffusion tensor imaging (DTI) were performed. Quantitative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were compared at stenotic and nonstenotic segments. Results: A statistically significant difference in mean FA and ADC values were seen at stenotic and nonstenotic segments. In the most stenotic segments, the mean FA value was 0.415 ± 0.203 and in the nonstenotic segment, the mean FA value was 0.717 ± 0.160, which was statistically significant (P < 0.001). The mean ADC value in the most stenotic segments was 1.777 ± 1.005 x 10-3 mm2/s and that of the nonstenotic segments was 1.010 ± 0.458 x 10-3 mm2/s. The difference in the mean ADC value was statistically significant (p <0.001). Conclusion: Use of diffusion tensor imaging (DTI) along with conventional MRI sequences enables early detection of the disease and helps in appropriate timing of surgery.
Keywords: Diffusion tensor imaging (DTI), cervical spondylotic myelopathy (CSM), apparent diffusion coefficient (ADC), fractional anisotropy (FA)
MULTIPLE PULMONARY ARTERY ANEURYSMS : A CASE REPORT OF PULMONARY VASCULITIS
CLINICAL HISTORY
Presenting history – A 24 year old male patient came with complaints of haemoptysis since 3months, aggravated on exertion around 3-4 episodes per day with around 3-4 ml of frank blood. No complaint of chest pain/ fever. No past history of PTB. No e/o significant past history. Patient tested negative for HLA b51 and Anti-nuclear antibody
Magnetic Resonance Cholangiopancreatography in 3 Tesla: 2D MRCP versus 3D MRCP in Diagnostic Evaluation with Special Reference to Different Acquisition and Reconstruction Planes
Purpose: Magnetic resonance cholangiopancreatography (MRCP) is an established technique for the evaluation of intra- and extrahepatic bile ducts in patients with known or suspected hepatobiliary disease. However, the ideal acquisition and reconstruction plane for optimal bile duct evaluation with 3D technique has not been evaluated.The purpose of our study was to compare different acquisition and reconstruction planes of 3D MRCP for bile duct assessment.
Methods: 51 consecutive adult patients suspected to have pancreatico-biliary disease were examined with 3 Tesla (Philips 3 T Ingenia) system both a multi thin slice (3D) and a breath-hold (Single Shot) MRCP technique were performed. In the multi thin slice technique both source images and maximum intensity projections were examined. Two radiologists blinded to clinical information viewed both MRCP techniques independantly. Measure of correlation between each of the techniques and the inter observer agreement were computed. Coronal and axial MIP were reconstructed based on each dataset (resulting in two coronal and two axial MIP, respectively) and assessed the MIP, regarding visualization of bile ducts and image quality.Results were compared (Wilcoxon test). Intra- and interobserver variability were calculated (kappa-statistic).
Results: In case of coronal data acquisition, visualization of bile duct segments was significantly better on coronal reconstructed MIP images as compared to axial reconstructed MIP (p \u3c 0.05). Regarding visualization, coronal MIP of the coronal acquisition were equal to coronal MIP of the axial acquisition (p \u3e 0.05). Image quality of coronal and axial datasets did not differ significantly. Obstruction due to tumor was shown in 30% of patients, and calculi in the common bile duct were shown also in 30% of patients employing the 3D MRCP technique. Obstruction due to tumor and calculi were shown in 30% and 21% of patients, respectively, using the SS 2D MRCP technique. Sensitivity and specificity in distinguishing calculi in the common bile duct by 3D MRCP and SS MRCP were 100%, 100%, 70% and 100% respectively.
Conclusions: Although the 3D MRCP multislice technique is more time consuming than the SS MRCP breath-hold technique at a 3 Tesla (Philips 3 T Ingenia) system it is advisable to use thin slice 3D MRCP in order not to misdiagnose calculi in the common bile duct.The results of our study suggest that for visualization and evaluation of intra- and extrahepatic bile duct segments reconstructed images in coronal orientation are preferable
Shear wave elastography: usefulness in chronic kidney disease
Purpose: Chronic kidney disease (CKD) is recognized as a major worldwide health problem. For all CKD, intra-renal fibrosis is a final common pathway that can be correlated with disease severity. Tissue stiffness can be measured non-invasively using shear wave elastography. This study evaluates the use of Young's modulus derived by SWE as a biomarker that can distinguish normal from diseased kidneys. Also, Young's modulus was correlated with Doppler findings and estimated glomerular filtration rate (eGFR). Material and methods: This prospective study was performed in 2 phases, in which initially 50 CKD patients and 50 controls were studied to arrive at a median Young's modulus value in both the groups. In the later phase, a cross-sectional comparative study was conducted on 58 diabetic and 56 non-diabetic patients with SWE and renal Doppler, and the findings were correlated in various stages of CKD. Results: Using Young’s modulus, the renal cortex elasticity of CKD patients was shown to be considerably reduced as compared to normal kidneys. There was significant correlation between Young's modulus, eGFR, and renal resistive index. Young's modulus values did not show significant differences between diabetic and non-diabetic groups, revealing its inability to arrive at the aetiopathogenesis of CKD. Conclusions: Correlation of renal tissue Young's modulus with eGFR suggests that SWE may be used as an indicator of renal tissue injuries in CKD patients. SWE can never replace the gold standard biopsy, but it can be used for staging of CKD. Even though SWE cannot predict the aetiopathogenesis of CKD, it may be a low-cost way to provide additional diagnostic information in CKD
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