853 research outputs found

    Combined experimental and theoretical study of poly(aniline-co-pyrrole) oligomer

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    Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole [Poly(Ani-co-Py)], through comparison of experimental and theoretically calculated properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV-vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer. A very nice correlation is found between the theory and experiment which consequences the structure of Poly(Ani-co-Py). Poly(Ani-co-Py) is not explored like other conducting polymers; however, by tuning this molecular structure, the electro-active nature of this material can be enhanced adequately

    Early renal damage assessed by the SLICC/ACR damage index is predictor of severe outcome in lupus patients in Pakistan

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    We investigated Patients with systemic lupus erythematosus with the objective of assessing whether early damage accrued in systemic lupus erythematosus as measured by the SLICC/ACR Damage Index predicts mortality in lupus Patients that have been followed prospectively in a single center. Patients with systemic lupus erythematosus from Aga Khan University hospital presenting between 1992 and 2007 were included. This enabled all Patients to be potentially followed for at least 10 years. Yearly SLICC/ACR Damage Index scores were determined for each Patient. Early damage was defined as a score \u3e= 1, and no damage as a score of 0 at the initial assessment. Kaplan-Meier and Log rank tests were used to compare the survival experience between those with and without damage, with all Patients being assessed at 10 years. In this inception cohort 198 Patients were identified and were followed for 10 years. Of these, 47 (23.7%) Patients had a SLICC/ACR Damage Index score of 0 (no damage) while 151 Patients (76.3%) had at least one SLICC/ACR Damage Index item scored (early damage). Mean renal damage score at 1, 5 and 10 years was 0.16, 0.34 and 0.67, respectively. Of lupus Patients who exhibited renal damage at their first SLICC/ACR Damage Index assessment, 31% died within 10 years of their illness as compared with only 13% who had no early renal damage (p \u3c 0.003). Mean renal damage score at 1 year after diagnosis was a significant predictor of death within 10 years of diagnosis (p \u3c 0.002)

    Renal involvement in systemic lupus erythematosus in Pakistan

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    Objective: To find the prevalence of lupus nephritis, delineate its clinical, immunological and therapeutic characteristics and compare them with the data worldwide.PATIENTS AND Methods: Between 1985 and 2001, 198 patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatism Association (ARA) admitted to the hospital were studied by means of a retrospective review of their records.Results: Renal involvement was found in 89 (45%) patients. Biopsy showed lupus nephritis in 42 patients; there were 9 male and 33 females. Mean age at initial presentation was 27 years and mean duration of follow-up was 2 .3 years. The histological types (WHO Classification) were mainly class. 4 (n = 27), class 3 (n = 7) and class 5 (n = 6). Immunoflourescence showed a predominantly granular pattern of IgG, IgA and C3. Renal manifestations included renal failure (50%), microscopic hematuria (67%), active urine sediment (22%), and proteinuria (74%). Proteinuria was nephrotic range in 45% patients. Treatment was with combinations of prednisolone and cyclophosphamide (n = 13), prednisolone and azathioprine (n = 27). 19 patients received high dose methyl prednisolone (1 gm/day for 3 days). There was no difference in mortality rate between prednisolone and cyclophosphamide and prednisolone and azathioprine treatment groups. The overall mortality rate was 17% (n = 7). Mortality was higher in WHO class 4 and 5 as compared to class 2 and 3 (p \u3c 0.001).CONCLUSION: The prevalence of lupus nephritis in our population is an intermediate between Caucasians and other Asians. Certain clinical characteristics in our patients with lupus nephritis are different as compared to various other studies. Because of limited resources for treatment in developing countries, we believe that patients with lupus nephritis should be treated with improved ancillary medical therapies and more effective immunosuppressive regimens

    Blood urea nitrogen as an early predictor of severity in acute pancreatitis

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    Background: Acute pancreatitis presents as acute abdominal pain and is usually associated with raised pancreatic enzyme levels in the blood or urine. Aims and objectives of the study was to evaluate the role of serial BUN measurement as an early prognostic marker of acute pancreatitis.Methods: From each patient detailed history was taken, general and systemic examination were done and relevant investigations were conducted. BUN was repeated after 24 hours and the change in the level of BUN was noted. Imaging in the form of CT after 72 hours of admission were performed in each patient. The severity of acute pancreatitis was gauged by modified CTSI and the same was compared to the change in BUN values over first 24 hours of admission.Results: Mean BUN values at ‘0’ hour in severe acute pancreatitis and non-severe acute pancreatitis were 31.91±6.79 and 15.44±5.95 mg/dl, respectively. The difference between the two groups was statistically significant with p value of <0.001. Similarly, the difference in BUN values at ‘24’ hours between the two groups was statistically significant. BUN value ≥23 mg/dl at ‘0’ hour was found to be the optimal cut off for determining the severity of pancreatitis with sensitivity of 91.3%. BUN ≥25 mg/dl at 24 hours was found to be the optimal cut-off for determining the severity of acute pancreatitis with sensitivity of 95.7%.Conclusions: BUN as a single marker for acute pancreatitis can be useful as it is easy to perform and cheap marker to predict severity without the need for complex calculations.

    Do clinical manifestations of Systemic Lupus Erythematosus in Pakistan correlate with rest of Asia?

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    Objective: Systemic Lupus Erythematosus (SLE) is known to be different among people with different racial, geographical and socio-economic back grounds. Asia has diverse ethnic groups broadly, Orientals in the East and Southeast Asia, Indians in South Asia and Arabs in the Middle East. These regions differ significantly from the Caucasians with reference to SLE. The purpose of this study was, therefore, to delineate the clinical pattern and disease course in Pakistani patients with SLE and compare it with Asian data.Methods: Patients with SLE fulfilling the clinical and laboratory criteria of the American Rheumatism Association admitted at the Aga Khan University Hospital between 1986 and 2001 were studied by means of a retrospective review of their records. The results were compared with various studies in different regions of Asia.Results: Demographically, it was seen that SLE is a disease predominantly of females in their third decade, which is generally consistent with Asian data. There was less cutaneous manifestations, arthritis, serositis, haematological and renal involvement compared to various regions in Asia. The neurological manifestations of SLE, however, place Pakistani patients in the middle of a spectrum between South Asians and other Asian races.CONCLUSION: This study has shown that the clinical characteristics of SLE patients in our country may be different to those of other Asian races. Although our population is similar to South Asians, but clinical manifestations of our SLE patients are considerably different, suggesting some unknown etiology. Further studies are required to confirm the above results and to find statistically sounder associations

    Rib suppression in frontal chest radiographs: A blind source separation approach

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    Chest radiographs play an important role in the diagnosis of lung cancer. Detection of pulmonary nodules in chest radiographs forms the basis of early detection. Due to its sparse bone structure and overlapping of the nodule with ribs and clavicles the nodule is difficult to detect in conventional chest radiographs. We present a technique based on Independent Component Analysis (ICA) for the suppression of posterior ribs and clavicles which will en-hance the visibility of the nodules and aid the radiologist in diagnosis. 1

    Pancreatic cystic neoplasms and post-inflammatory cysts: interobserver agreement and diagnostic performance of MRI with MRCP

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    Purpose: We aimed to answer several clinically relevant questions; (1) the interobserver agreement, (2) diagnostic performance of MRI with MRCP for (a) branch duct intraductal papillary mucinous neoplasms (BD-IPMN), mucinous cystic neoplasms (MCN) and serous cystic neoplasms (SCN), (b) distinguishing mucinous (BD-IPMN and MCN) from non-mucinous cysts, and (c) distinguishing three pancreatic cystic neoplasms (PCN) from post-inflammatory cysts (PIC). Methods: A retrospective analysis was performed at a tertiary referral center for pancreatic diseases on 71 patients including 44 PCNs and 27 PICs. All PCNs were confirmed by surgical pathology to be 17 BD-IPMNs, 13 MCNs, and 14 SCNs. Main duct and mixed type IPMNs were excluded. Two experienced abdominal radiologists blindly reviewed all the images. Results: Sensitivity of two radiologists for BD-IPMN, MCN and SCN was 88-94%, 62-69% and 57-64%, specificity of 67-78%, 67-78% and 67-78%, and accuracy of 77-82%, 65-75% and 63-73%, respectively. There was 80% sensitivity, 63-73% specificity, 70-76% accuracy for distinguishing mucinous from non-mucinous neoplasms, and 73-75% sensitivity, 67-78% specificity, 70-76% accuracy for distinguishing all PCNs from PICs. There was moderate-to-substantial interobserver agreement (Cohen's kappa: 0.65). Conclusion: Two experienced abdominal radiologists had moderate-to-high sensitivity, specificity, and accuracy for BD-IPMN, MCN, and SCN. The interobserver agreement was moderate-to-substantial. MRI with MRCP can help workup of incidental pancreatic cysts by distinguishing PCNs from PICs, and premalignant mucinous neoplasms from cysts with no malignant potential

    Assessment of the influence of lung inflation state on the quantitative parameters derived from hyperpolarized gas lung ventilation MRI in healthy volunteers.

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    In this study, the effect of lung volume on quantitative measures of lung ventilation was investigated using MRI with hyperpolarized 3He and 129Xe. Six volunteers were imaged with hyperpolarized 3He at five different lung volumes (residual volume (RV), RV+1L, functional residual capacity (FRC), FRC+1L and total lung capacity (TLC)), and three were also imaged with hyperpolarized 129Xe. Imaging at each of the lung volumes was repeated twice on the same day with corresponding 1H lung anatomical images. Percentage lung ventilated volume (%VV) and variation of signal intensity (heterogeneity score, Hscore) were evaluated. Increased ventilation heterogeneity, quantified by reduced %VV and increased Hscore, was observed at lower lung volumes with the least ventilation heterogeneity observed at TLC. For 3He MRI data, the coefficient of variation of %VV was less than 1.5% and less than 5.5% for Hscore at all lung volumes, whilst for 129Xe data the values were 4% and 10% respectively. Generally, %VV generated from 129Xe images was lower than that seen from 3He images. The good repeatability of 3He %VV found here supports prior publications showing that percentage lung ventilated volume is a robust method for assessing global lung ventilation. The greater ventilation heterogeneity observed at lower lung volumes indicates that there may be partial airway closure in healthy lungs and that lung volume should be carefully considered for reliable longitudinal measurements of %VV and Hscore. The results suggest that imaging patients at different lung volumes may help to elucidate obstructive disease pathophysiology and progression

    Transition metal doped CeO2 for photocatalytic removal of 2-chlorophenol in the exposure of indoor white light and antifungal activity

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    Besides natural sunlight and expensive artificial lights, economical indoor white light can play a significant role in activating a catalyst for photocatalytic removal of organic toxins from contaminated water. In the current effort, CeO2 has been modified with Ni, Cu, and Fe through doping methodology to study the removal of 2-chlorophenol (2-CP) in the illumination of 70 W indoor LED white light. The absence of additional diffractions due to the dopants and few changes such as reduction in peaks’ height, minor peak shift at 2θ (28.525°) and peaks’ broadening in XRD patterns of modified CeO2 verifies the successful doping of CeO2. The solid-state absorption spectra revealed higher absorbance of Cu-doped CeO2 whereas a lower absorption response was observed for Ni-doped CeO2. An interesting observation regarding the lowering of indirect bandgap energy of Fe-doped CeO2 (∼2.7 eV) and an increase in Ni-doped CeO2 (∼3.0 eV) in comparison to pristine CeO2 (∼2.9 eV) was noticed. The process of e-– h+ recombination in the synthesized photocatalysts was also investigated through photoluminescence spectroscopy. The photocatalytic studies revealed the greater photocatalytic activity of Fe-doped CeO2 with a higher rate (∼3.9 × 10−3 min-1) among all other materials. Moreover, kinetic studies also revealed the validation of the Langmuir-Hinshelwood kinetic model (R2 = 0.9839) while removing 2-CP in the exposure of indoor light with a Fe-doped CeO2 photocatalyst. The XPS analysis revealed the existence of Fe3+, Cu2+ and Ni2+ core levels in doped CeO2. Using the agar well-diffusion method, the antifungal activity was assessed against the fungus M. fructicola and F. oxysporum. Compared to CeO2, Ni-doped CeO2, and Cu-doped CeO2 nanoparticles, the Fe-doped CeO2 nanoparticles have outstanding antifungal properties
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