Optimal Design of Ceramic Based Hip Implant Composites Using Hybrid AHP-MOORA Approach.

Designing excellent hip implant composite material with optimal physical, mechanical and wear properties is challenging. Improper hip implant composite design may result in a premature component and product failure. Therefore, a hybrid decision-making tool was proposed to select the optimal hip implant composite according to several criteria that are probably conflicting. In varying weight proportions, a series of hip implant composite materials containing different ceramics (magnesium oxide, zirconium oxide, chromium oxide, silicon nitride and aluminium oxide) were fabricated and evaluated for wear and physicomechanical properties. The density, void content, hardness, indentation depth, elastic modulus, compressive strength, wear, and fracture toughness values were used to rank the hip implant composites. It was found that the density and void content of the biocomposites remain in the range of 3.920-4.307 g/cm3 and 0.0021-0.0089%, respectively. The composite without zirconium oxide exhibits the lowest density (3.920 g/cm3), while the void content remains lowest for the composite having no chromium oxide content. The highest values of hardness (28.81 GPa), elastic modulus (291 GPa) and fracture toughness (11.97 MPa.m1/2) with the lowest wear (0.0071 mm3/million cycles) were exhibited by the composites having 83 wt.% of aluminium oxide and 10 wt.% of zirconium oxide. The experimental results are compositional dependent and without any visible trend. As a result, selecting the best composites among a group of composite alternatives becomes challenging. Therefore, a hybrid AHP-MOORA based multi-criteria decision-making approach was adopted to choose the best composite alternative. The AHP (analytic hierarchy process) was used to calculate the criteria weight, and MOORA (multiple objective optimisation on the basis of ratio analysis) was used to rank the composites. The outcomes revealed that the hip implant composite with 83 wt.% aluminium oxide, 10 wt.% zirconium oxide, 5 wt.% silicon nitride, 3 wt.% magnesium oxide, and 1.5 wt.% chromium oxide had the best qualities. Finally, sensitivity analysis was conducted to determine the ranking's robustness and stability concerning the criterion weight.

Thermal and Sliding Wear Properties of Wood Waste-Filled Poly(Lactic Acid) Biocomposites.

In our study, the effects of wood waste content (0, 2.5, 5, 7.5, and 10 wt.%) on thermal and dry sliding wear properties of poly(lactic acid) (PLA) biocomposites were investigated. The wear of developed composites was examined under dry contact conditions at different operating parameters, such as sliding velocity (1 m/s, 2 m/s, and 3 m/s) and normal load (10 N, 20 N, and 30 N) at a fixed sliding distance of 2000 m. Thermogravimetric analysis demonstrated that the inclusion of wood waste decreased the thermal stability of PLA biocomposites. The experimental results indicate that wear of biocomposites increased with a rise in load and sliding velocity. There was a 26-38% reduction in wear compared with pure PLA when 2.5 wt.% wood waste was added to composites. The Taguchi method with L25 orthogonal array was used to analyze the sliding wear behavior of the developed biocomposites. The results indicate that the wood waste content with 46.82% contribution emerged as the most crucial parameter affecting the wear of PLA biocomposites. The worn surfaces of the biocomposites were examined by scanning electron microscopy to study possible wear mechanisms and correlate them with the obtained wear results.

Biosynthesis, characterization and antibacterial activity of silver nanoparticles using an endophytic fungal supernatant of Raphanus sativus.

In this study, biological synthesis of silver nanoparticles (AgNPs) from supernatant of endophytic fungus Alternaria sp. isolated from the healthy leaves of Raphanus sativus is studied. The synthesized AgNPs are characterized using UV-vis spectroscopy and Fourier transform-infrared spectroscopy (FTIR). The structural analysis is done by powder X-ray diffraction (XRD) method. The stability of AgNPs is studied by dynamic light scattering (DLS) method. The size and shape of AgNPs are observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM) and found to be spherical with an average particles size of 4-30 nm. Further, these AgNPs have been found to be highly toxic against human pathogenic bacteria, suggesting the possibility of using AgNPs as efficient antibacterial agents.

Infective endocarditis caused by Stenotrophomonas maltophilia: A report of two cases and review of literature.

Stenotrophomonas maltophilia is known for nosocomial habitat. Infective endocarditis due to this organism is rare and challenging because of resistance to multiple broad-spectrum antibiotic regimens. Early detection and appropriate antibiotic based on culture sensitivity reports are the key to its management. We report the diagnosis, treatment, and outcome of two cases of infective endocarditis caused by S. maltophilia.

Infective Endocarditis of the Left Main to Right Atrial Coronary Cameral Fistula.

A 7-year-old female child presented with pyrexia of unknown origin. She had received an empirical regimen of antibiotic for possible endocarditis. Evaluation included multiple imaging supports and blood culture. She had left main coronary artery to right atrium coronary cameral fistula, restricted patent ductus arteriosus, vegetation at the right atrial exit of fistula and negative blood culture. Ongoing fever more than 2 weeks, oscillating vegetation in the echo and histopathological evidence of healing vegetation suggested definite diagnosis of infective endocarditis. She was treated successfully by surgical closure of fistula from the right atrial approach. Device closure in this case would have resulted in a large residual cul-de-sac with or without tiny residual high-velocity jets, either being a threat for future enlargement, rupture of the residual aneurysmal sac, thromboembolism, prolonged anticoagulation, and infective endocarditis.

Pryce type I sequestration: no mosquito shooting.

We report a case of a 40-year-old woman with congenital dual arterial supply to an otherwise normal left lower lobe, causing hyperperfusion lung injury. In addition to near normal pulmonary arterial supply, the lower lobe of the left lung received a systemic arterial supply from the descending thoracic aorta. The patient was successfully managed by surgical ligation of the systemic arterial supply without lobectomy. We discuss when to defer lobectomy in Pryce type I sequestration.

Reliability of Doppler-Based Measurement of Pulmonary Vascular Resistance in Congenital Heart Disease with Left-to-Right Shunt Lesions.

BACKGROUND: Pulmonary vascular resistance (PVR) is a crucial parameter in the management of patients with left-to-right shunt lesions. Cardiac catheterization (Cath) is the gold standard test to assess PVR (PVRcath ), but it is invasive and hence, risky in children with pulmonary arterial hypertension (PAH). A noninvasive tool to assess PVR is desirable. Ratio of tricuspid regurgitation velocity (TRV) and time-velocity integral of right ventricular outflow tract (TVIRVOT ) by Doppler was previously shown to be a reliable noninvasive method for estimation of PVR in acquired PAH. METHODS: Peak TR velocity and TVIRVOT were recorded from 63 prospective patients with various congenital shunt lesions. Subsequently, the patients were subjected to cath in less than 2 hours. The patients were subdivided into four subsets based on age and pulmonary arterial mean pressure (PAMP). A regression equation was developed for calculation of PVR from TRV/TVIRVOT (PVREcho ) which was indexed for BSA (PVRIEcho ). Bland-Altman analysis was done for agreement between PVRIcath and PVRIEcho . Receiver operating characteristic (ROC) curves were plotted to test the identity of the two methods and also the applicability of PVRIEcho across a wide range of Wood units. RESULTS: Receiver operating characteristic curve plotted between the two methods showed good identity. Bland-Altman analysis showed excellent agreement between the two methods with negligible bias. ROC curves showed that PVRIEcho was accurate in distinguishing different cutoff values of PVR in each of the 4 groups. CONCLUSION: Noninvasive Doppler estimation of PVR is reliable in patients with shunt lesions over a wide range of PVR.

Coffin-Siris syndrome with the rarest constellation of congenital cardiac defects: A case report with review of literature.

We report a case of type-A Coffin-Siris syndrome (CSS) with a unique constellation of congenital heart defects. A 17-year-old Indian boy was referred to our hospital for central cyanosis with features of right heart failure. The cardiac abnormalities included biventricular outflow tract obstruction, small atrial septal defect (ASD), subaortic ventricular septal defect, drainage of left superior venacava to left atrial appendage, and aortic arch anomaly. Patient underwent successful right ventricular infundibular resection, subaortic membrane resection, closure of atrial and ventricular septal defect, rerouting left superior vena cava to left pulmonary artery and aortic valve replacement.

Surgical exclusion of postsurgical pseudoaneurysm of the ascending aorta.

Pseudoaneurysm of ascending aorta after cardiac surgery is rare in children. We report a case of successful surgical exclusion of ascending aortic pseudoaneurysm in a 15-year-old boy. The neck of the aneurysm was in close proximity to the right coronary artery (RCA).

Prevalence of rheumatic and congenital heart disease in school children of Andhra Pradesh, South India.

OBJECTIVE: To determine the prevalence of rheumatic heart disease (RHD) and congenital heart disease (CHD) using clinical and echocardiographic criteria in rural and urban school children in Andhra Pradesh, South India. MATERIALS AND METHODS: A total of 4213 school children between 5 and 16 years of age were screened. 1177 were from rural schools and 3036 from urban schools. Prevalence of RHD and CHD was estimated. RESULTS: Clinically RHD was present in 3 (prevalence 0.7/1000). Using echocardiography RHD was detected in 32 (7.6/1000), 11 (7.3/1000) from rural and 21 (7/1000) from urban schools. (P = 0.000, O.R = 0.093 and C.I. = 0.023-0.317). Total prevalence of RHD is 8.3/1000. Clinically CHD was present in 39 (9.2/1000) children, rural 9 (7.6/1000) and urban 30 (9.9/1000). Using echocardiography CHD was detected in 44 (10.4/1000) children, rural 11 (9.3/1000) and urban 33 (10.8/1000). CONCLUSION: RHD was detected several fold using echocardiographic screening than by clinical examination alone. Longitudinal follow-up of children with echocardiographically diagnosed subclinical RHD is needed.

A rare case of left lung hypoplasia associated with congenital pulmonary artery aneurysm and ventricular septal defect.

This report describes a 3-year-old boy who presented with hemoptysis and a history of congenital heart disease detected at the age of 3 months. Clinical and laboratory evaluation showed a large true congenital pulmonary artery aneurysm of the left main pulmonary artery occupying the entire left hemithorax and two small aneurysms in the right lung. In addition, a restricted ventricular septal defect was detected. It was evident on clinical and histologic grounds that the multiple aneurysms seen in this child stemmed from congenital weakness of the arterial wall in conjunction with increased pulmonary blood flow and elevated pulmonary artery pressure.

Doehle-Heller aortitis: speed of decision is what saves life.

A 48-year-old woman presented with severe acute heart failure of 7 days duration. Because of her rapidly worsening clinical condition, anatomical diagnosis of aortopulmonary fistula was made by urgent cardiac catheterization, and she successfully underwent immediate surgical closure. Retrospectively, the diagnosis of syphilitic aortitis complicated with aortopulmonary fistula was made by clinical profile, serology, and histopathology.

Myocardial infarction in children: Two interesting cases.

Myocardial infarction in children is extremely rare and can have various etiologies. The following two case reports highlight rare but important causes of myocardial infarction in children.

Endovascular stenting for native coarctation in older children and adolescents using adult self-expanding (Nitinol) iliac stents.

BACKGROUND: The role of balloon-expandable stents for native coarctation has been proven in several small studies. Use of Nitinol-made self-expanding stents in such situations is reported in adults in only a few cases. For the last 5 years we used self expanding nitinol stents (primarily recommended for iliac angioplasty in adults in this condition in older children. METHODS: There were 32 patients in total (24 males; mean age 10.2 +/- 1.43 years; youngest 6-years-old). Successful procedure is defined as reduction of gradient to less than 20 mmHg or increase in the ratio of the diameter of the coarctation area to the diameter of the descending aorta to at least 0.8. Bard luminexx vascular stents were used in all cases. RESULTS: In 32 patients 32 stents were used with overall success rate of 31/32 (96.8%). The peak systolic pressure gradient (mean (SD) decreased from 48.8 (23.5) to 2.2 (1.86) mm Hg (p<0.05). The diameter of the stenotic lesion increased from 5.6 (1.6) mm to 12.5 (2.6) (p<0.05). In one patient 2 stents were used because the first stent migrated downwards leaving the lesion partially uncovered. Nitinol stents were easier to deploy and conformed well to aortic walls. In the only unsuccessful case, the lesion was 12 mm long, tubular and did not yield even at 16 atm pressure. This case was taken up for elective surgery at a later date. There were no deaths or cerebrovascular events. Two cases had femoral artery access related problems (hematoma-1, loss of pulse-1). Twenty five of the 31 successful cases were on regular follow-up. On mean follow-up of 1.25 years one had re-coarctation and successful balloon dilation was done. Another case with re-coarctation and persistent hypertension underwent elective surgical repair. There were no aortic aneurysms in any case. CONCLUSIONS: Stent implantation using this readily available low cost adult peripheral self-expanding stents gave gratifying, acute and early term results in treatment of coarctation of aorta in older children and adolescents. Ease of deployment, conforming to the aortic anatomy and low cost appear the main advantages of these stents.

Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: a pilot study.

BACKGROUND: Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operator skills. It requires intensive resource involvement. For epidemiological studies these methods are not suitable. The aim of our study was to clinically evaluate the validity and reproducibility of a new automatic device for measurement of pulse wave velocity that can be used in such studies. METHODS: In 44 subjects including normal healthy control and patients with coronary artery disease, heart brachial, heart ankle, brachial ankle and carotid femoral pulse wave velocities were recorded by using a new oscillometric device. Lead I and II electrocardiogram and pressure curves were simultaneously recorded. Two observers recorded the pulse wave velocity for validation and one observer recorded the velocity on two occasions for reproducibility. RESULTS AND DISCUSSION: Pulse wave velocity and arterial stiffness index were recorded in 24 control and 20 coronary artery disease patients. All the velocities were significantly high in coronary artery disease patients. There was highly significant correlation between the values noted by the two observers with low standard deviation. The Pearson's correlation coefficient for various velocities ranged from (r = 0.88-0.90) with (p < 0.0001). The reproducibility was also very good as shown by Bland-Altman plot; most of the values were lying within 2 SD. The interperiod measurements of pulse wave velocity were also significantly correlated (r = 0.71-0.98) (P < 0.0001). Carotid-femoral pulse wave velocity was found to correlate significantly with heart brachial, heart ankle, brachial ankle pulse wave velocity and arterial stiffness index values. Reproducibility of our method was good with very low variability in both interobserver and interperiod analysis. CONCLUSION: The new device "PeriScope" based on oscillometric technique has been found to be a simple, non-invasive and reproducible device for the assessment of pulse wave velocity and can be used to determine arterial stiffness in large population based studies.