Search

Zirconia ceramics are versatile materials with remarkable properties such as a high thermal resistance, high fracture strength, and low thermal conductivity. They are chemically inert and highly wear- and corrosion-resistant, making them ideal for a wide range of applications in the aerospace, automotive, and biomedical fields. In dentistry, zirconia ceramics are used for veneers, crowns, bridges, and implants because of their biocompatibility. Despite the various benefits of zirconia ceramics, they are difficult to process because of their high hardness and brittleness. Additive manufacturing (AM) has proven to be a viable alternative to conventional fabrication processes, particularly for the processing of difficult-to-cut materials. AM of ceramics has gained significant attention in recent years because of its flexibility and ability to produce customized geometries rapidly and economically. In this study, the digital light processing (DLP) technique was employed to 3D print yttria-stabilized zirconia. The fabricated zirconia was evaluated and characterized for use in dental applications. Thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) were performed on the green body to assess the decomposition of the additives in the slurry and determine the debinding temperatures. The as-built parts were subjected to debinding and sintering to obtain fully dense zirconia parts. The parts tended to shrink after sintering; therefore, the shrinkage ratios were evaluated and found to be 1.2817, 1.2900, and 1.3388 in the x-, y-, and z-directions, respectively. The average density after sintering was 6.031 g/cc. The flexural strength determined using four-point bending tests was 451.876 MPa, and the tensile and compressive strengths were 143 MPa and 298.4 MPa, respectively.

The buffer allocation problem concerning the size and location of storage between the stages of a flow line is a critical research area in the design of production lines. In this study, a production system consisting of two unreliable stages and a buffer between them is considered; the first stage incorporates two identical machines in parallel and the second stage consists of a single machine. A simulation model is designed and used to evaluate the effect of the buffer capacity and the repair rates of machines on production line efficiency. The results revealed the capacity of buffer that yields the maximum production line efficiency with various repair rate values. Keywords: Buffer allocation, Flow line, Simulation model, Production line efficiency

Bicuspid aortic valve is the most common congenital cardiac malformation, affecting 1%–2% of the population. Among various complications, incidence of infective endocarditis (IE) in the bicuspid aortic valve population is high with higher rate of periannular extension resulting in conduction disturbances. Here we are reporting a rare case of infective endocarditis of bicuspid aortic valve presented with alternating bundle branch block.

In clinical setting, congestive heart failure (CHF) and chronic kidney disease (CKD) often co-exist in patients due to common underlying predisposing factors. An intricate equilibrium between the cardiovascular and renal system is maintained through rennin angiotensin-aldosterone axis and autonomic nervous system. Consequent to favorable hemodynamic modification, angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blocking (ARB) therapy have proven to be an indispensable aspect of heart failure management with morbidity and mortality benefit. Additionally, progression to end stage renal failure may be halted by renin angiotensin aldosterone system (RAAS) blockade in patients with preexisting renal dysfunction. However, concern over the safety of RAAS blockade in presence of renal impairment has led to profound underutilization of these drugs in CHF patients with renal insufficiency. This review aims to provide a simplified guide to pathophysiology and management options of this perplexing situation., (Copyright © 2016 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

Background: Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to examine whether ivabradine was superior to atenolol for achieving higher exercise capacity in patients with moderate mitral stenosis in sinus rhythm. We also evaluated their effects on left ventricular myocardial performance index (MPI)., Methods and Results: Eighty-two patients with moderate mitral stenosis in sinus rhythm were randomized to receive ivabradine (n=42) 5mg twice daily or atenolol (n=40) 50mg daily for 6 weeks. Transthoracic echocardiography and treadmill test were performed at baseline and after completion of 6 weeks of treatment. Mean total exercise duration in seconds markedly improved in both study groups at 6 weeks (298.57±99.05s vs. 349.12±103.53s; p=0.0001 in ivabradine group, 290.90±92.42s vs. 339.90±99.84s; p=0.0001 in atenolol group). On head-to-head comparison, there was no significant change in improvement of exercise time between ivabradine and atenolol group (p=0.847). Left ventricular MPI did not show any significant change from baseline and at 6 weeks in both drug groups (49.8%±8% vs. 48.3%±7% in ivabradine group, 52.9%±10% vs. 50.9%±10% in atenolol groups; p=0.602)., Conclusion: Ivabradine or atenolol can be used for heart rate control in patients with moderate mitral stenosis in sinus rhythm. Ivabradine is not superior to atenolol for controlling heart rate or exercise capacity. Left ventricular MPI was unaffected by either of the drugs., (Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

A patient presented with chest pain and clinical features of acute right heart failure. Initial work up revealed the presence of severe PAH. Acute pulmonary embolism is the commonest and most life-threatening cause for acute cor pulmonale. Even though the clinical picture suggested pulmonary embolism, a subtle sign was missed from the first chest X-ray taken in the emergency department. However on reanalysis the 'continuous diaphragm sign' later guided us towards the diagnosis. Our case represents one of the first reports of a rare etiology for acute cor pulmonale--hypersensitivity pneumonitis. Right ventricular dysfunction was caused by an acute rise in pulmonary artery pressures as well as by the compressive effects of pneumomediastinum. We emphasize the role played by a good quality chest X-ray early in the management of acute chest pain syndromes. However pulmonary embolism should be ruled out conclusively before redirecting attention to less malignant conditions., (Copyright © 2014 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

Isolated chylopericardium due to cystic lymphangioma of pericardium is a rare entity. We report a case of asymptomatic chylopericardium in a young male who presented with cardiomegaly. Echocardiography revealed massive pericardial effusion without tamponade. Pericardiocentesis yielded 1.25 L of tea-colored fluid which showed triglyceride level of 1723 mg/dL and cholesterol of 1021 mg/dL with a cholesterol to triglyceride ratio of <1, characteristic of chylous fluid. Lymphoscintigraphy using 99Tc demonstrated lymphatic leak around the heart region. Fusion of MRI images with lymphoscintigraphy was taken with a view of localizing the leak site; it demonstrated enhancement in the pericardial space. Surgery was done via right lateral thoracotomy. Thoracic duct was ligated above diaphragm and pericardial window created by anterior pericardiectomy. The patient had an uneventful recovery and was well after 6 months of follow up. Pericardial biopsy showed cystic lymphangioma of pericardium., (Copyright © 2013 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

Background: Presence of right ventricular (RV) infarction imposes a higher risk of adverse events in inferior wall myocardial infarction (IWMI). In this study, we attempted to correlate various indices of RV function assessed by echocardiography with presence of a proximal right coronary artery (RCA) stenosis in patients with first episode of acute IWMI., Methods: In a prospective study, patients with first episode of acute IWMI underwent echocardiographic assessment within 24 h of symptom onset and indices of RV function viz. RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), myocardial performance index (MPI) and tissue Doppler velocities from RV free wall were measured. Patients who underwent coronary angiogram (CAG) within one month and they were classified into group 1 and group 2 based on the presence or absence, respectively, of a significant proximal RCA stenosis., Results: There were 90 patients with first episode of IWMI of which 67 patients underwent CAG. There was significant difference between group 1 (n = 26) and group 2 (n = 41) in TAPSE (13.5 ± 1.3 vs 21.3 ± 1.7, p < 0.001), MPI by tissue Doppler (0.87 ± 0.1 vs 0.55 ± 0.2, p < 0.001) and in tissue Doppler systolic velocity from RV free wall (S' 9.8 ± 1.1 vs 15.0 ± 1.5, p < 0.001). There was a good interobserver correlation for TAPSE, MPI by TDI, and S' velocity. TAPSE ≤ 16 (sensitivity 93%, specificity 100%), MPI-TDI ≥ 0.69 (sensitivity 94.7%, specificity 93.5%), S ≤ 12.3 (sensitivity 90.3%, specificity 94.3%) were useful in predicting presence of proximal RCA stenosis., Conclusion: RV function indices like TAPSE, MPI-TDI and S' velocity are useful in predicting proximal RCA stenosis in first episode of acute IWMI., (Copyright © 2013 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)

Objective: Dysfunction of the coronary microcirculation is considered as one of the factors responsible for symptoms and abnormal stress tests in patients with angina and normal coronaries (syndrome X). We sought to evaluate the usefulness of coronary sinus filling time (CSFT) to assess coronary microcirculation in this group of patients., Methods: We compared the CSFT of patients having definite angina or atypical angina with positive treadmill electrocardiography test (angina group), with that of patients undergoing coronary angiogram (CAG) prior to balloon mitral valvuloplasty (control group). During CAG, coronary sinus was visualized in appropriate views and CSFT in seconds was derived from frame count. Thrombolysis In Myocardial Infarction (TIMI) flow grade, corrected TIMI (cTIMI) frame count, TIMI Myocardial Perfusion grade (TMP) were assessed., Results: There were 41 patients in angina group and 16 in control group. Among the angina group 68.8% were females as against 81.8% in the control group. 87.8% (n = 36) had typical angina. Mean CSFT was 4.25 ± 0.72 s and 3.46 ± 0.99 s in the angina group and control group respectively (p = 0.001). No significant differences were found between the groups with respect to TMP (p = 0.68) & cTIMI frame count (p = 0.22)., Conclusion: CSFT is a simple method to assess the transit time through coronary microcirculation. CSFT was significantly delayed in patients with angina and normal coronaries. TMP and cTIMI frame count were not significantly different between groups., (Copyright © 2013 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.)