Mechanical and Tribological Behavior of Mechanically Alloyed Ni-TiC Composites Processed via Spark Plasma Sintering

Titanium carbide (TiC) reinforced nickel (Ni) matrix composites were processed via mechanical alloying (MA) followed by spark plasma sintering (SPS) process. Mechanical alloying has gained special attention as a powerful non-equilibrium process for fabricating amorphous and nanocrystalline materials, whereas spark plasma sintering (SPS) is a unique technique for processing dense and near net shape bulk alloys with homogenous microstructure. TiC reinforcement varied from 5 to 50 wt.% into nickel matrix to investigate its effect on the microstructure and mechanical behavior of Ni-TiC composites. All Ni-TiC composites powder was mechanically alloyed using planetary high energy ball mill with 400 rpm and ball to powder ratio (BPR) 15:1 for 24 h. Bulk Ni-TiC composites were then sintered via SPS process at 50 MPa pressure and 900–1200 °C temperature. All Ni-TiC composites exhibited higher microhardness and compressive strength than pure nickel due to the presence of homogeneously distributed TiC particles within the nickel matrix, matrix grain refinement, and excellent interfacial bonding between nickel and TiC reinforcement. There is an increase in Ni-TiC composites microhardness with an increase in TiC reinforcement from 5 to 50 wt.%, and it reaches the maximum value of 900 HV for Ni-50TiC composites.     

Use of a novel hemoadsorption device for cytokine removal as adjuvant therapy in a patient with septic shock with multi-organ dysfunction: A case study

CytoSorb^® (CytoSorbents Corporation, USA) is a novel sorbent hemoadsorption device for cytokine removal. The aim of this study was to examine the clinical use of CytoSorb^® in the management of patient with septic shock. We used this device as an adjuvant to stabilize a young patient with multi-organ failure and severe sepsis with septic shock. A 36-year-old female patient was hospitalized with the complaints of malaise, general body ache, and breathing difficulty and had a medical history of diabetes mellitus type II, hypertension, obstructive sleep apnea, hypothyroidism and morbid obesity. She was diagnosed to have septic shock with multi-organ dysfunction (MODS) and a low perfusion state. CytoSorb^® hemoadsorption column was used as an attempt at blood purification. Acute physiology and chronic health evaluation score, MODS score, and sequential organ failure assessment score were measured before and after the device application. CytoSorb application as an adjuvant therapy could be considered in septic shock.     

300,000 IU or 600,000 IU of oral vitamin D3 for treatment of nutritional rickets: A randomized controlled trial

Objective

To evaluate the non-inferiority of a lower therapeutic dose (300,000 IU) in comparison to standard dose (600,000) IU of Vitamin D for increasing serum 25(OH) D levels and achieving radiological recovery in nutritional rickets.

Design

Randomized, open-labeled, controlled trial.

Setting

Tertiary care hospital.

Participants

76 children (median age 12 mo) with clinical and radiologically confirmed rickets.

Intervention

Oral vitamin D3 as 300,000 IU (Group 1; n=38) or 600,000 IU (Group 2; n=38) in a single day.

Outcome variables

Primary: Serum 25(OH)D, 12 weeks after administration of vitamin D3; Secondary: Radiological healing and serum parathormone at 12 weeks; and clinical and biochemical adverse effects.

Results

Serum 25(OH)D levels [geometric mean (95% CI)] increased significantly from baseline to 12 weeks after therapy in both the groups [Group 1: 7.58 (5.50–10.44) to 16.06 (12.71–20.29) ng/mL, P<0.001]; Group 2: 6.57 (4.66–9.25) to 17.60 (13.71–22.60, P<0.001]. The adjusted ratio of geometric mean serum 25(OH)D levels at 12 weeks between the groups (taking baseline value as co-variate) was 0.91 (95% CI: 0.65–1.29). Radiological healing occurred in all children by 12 weeks. Both groups demonstrated significant (P<0.05) and comparable fall in the serum parathormone and alkaline phosphatase levels at 12 weeks. Relative change [ratio of geometric mean (95% CI)] in serum PTH and alkaline phosphatase, 12 weeks after therapy, were 0.98 (0.7–1.47) and 0.92 (0.72–1.19), respectively. The serum 25(OH)D levels were deficient (<20 ng/mL) in 63% (38/60) children after 12 weeks of intervention [Group 1: 20/32 (62.5%); Group 2: 18/28 (64.3%)]. No major clinical adverse effects were noticed in any of the children. Hypercalcemia was documented in 2 children at 4 weeks (1 in each Group) and 3 children at 12 weeks (1 in Group 1 and 2 in Group 2). None of the participants had hypercalciuria or hypervitaminosis D.

Conclusion

A dose of 300,000 IU of vitamin D3 is comparable to 600,000 IU, administered orally, over a single day, for treating rickets in under-five children although there is an unacceptably high risk of hypercalcemia in both groups. None of the regime is effective in normalization of vitamin D status in majority of patients, 3 months after administering the therapeutic dose.     

A study of clinical presentation and delays in management of acute myocardial infarction in community

To assess the medico social demographics of acute myocardial infarction (AMI) in our community we studied 609 patients presenting between January 2008 to December 2008 with a detailed questionnaire in four centres of UP. Medical attention was sought late (> 6 hours) in 316 (51.6%), thrombolysis was obtained in 45.2% (275) and presentation was atypical in 16.3% (99). 36.2% (221) had pre-monitory symptoms of which 68% (150) ignored the same while of 32% (71) who did seek medical attention 47.9% (37) were brushed away as non-cardiac in origin. 20.3% (46/226) of hypertension, 23.2% (43/185) of diabetes and 83.4% (91/109) of hyperlipidaemia was diagnosed post event. We conclude that at least half of patients with AMI do not get definitive therapy, at least one in 10 patients do not have the classical symptoms, reasonable proportion are unaware of their risk factors, and a good majority have pre-monitory symptoms which get overlooked.     

Atrial fibrillation in a tertiary care institute – A prospective study

ObjectiveAtrial fibrillation is the commonest sustained arrhythmia. In western countries the common causes of atrial fibrillation are hypertensive heart disease, dilated cardiomyopathy, and coronary heart disease. Rheumatic heart disease being still common in India, we studied its contribution to atrial fibrillation.Material and methods137 consecutive patients of atrial fibrillation coming to our hospital were subjected to echocardiography to determine the cause.ResultsOut of 137 patients with atrial fibrillation, 76 were female (55.47%) and 61 were male (44.43%). Mean age was 51.24 ± 15.36 years. Commonest cause of AF was rheumatic heart disease found in 84 (61.31%) patients. Next common causes were hypertensive heart disease in 14 (10.2%) patients and chronic obstructive pulmonary disease (COPD) in 14 (10.2%) patients. Mean left atrial size was 47.8 ± 12.25 mm.ConclusionIn our study of patients coming from a rural back ground of North India, more than 60% patients of AF are due to RHD. Hypertensive heart disease and COPD are the next common causes.     

Assessment of dental anxiety and its correlation with denture satisfaction in edentulous patients

Objective: The objectives of this study were to measure the level of dental anxiety and its correlation with dental history, denture satisfaction and other variables. Materials and methods: A cross-sectional study was conducted on 150 completely edentulous patients reporting to the Department of Prosthodontics, KLES's Institute of Dental Sciences, Belgaum, over a period of 17 months (August 2005 to March 2007). The anxiety level of the patients was assessed with the help of a questionnaire, after obtaining an informed consent. Reliability of the dental anxiety scale was assessed by means of coefficient alpha. Results: The results of this study concluded that dental anxiety scale for edentulous patients was a reliable scale for measuring dental anxiety. The anxiety score was higher for female than male patients. A significant correlation was found between denture satisfaction score and anxiety. Discussion: Anxiety plays a major role in denture satisfaction. The variables included: Previous denture experience, occupation, medical history, age, gender, dental anxiety scale, period of edentulousness, age of previous dentures, number of complete dentures, denture satisfaction score, and the score on the Hamilton anxiety scale Conclusion: The study indicated that gender correlates significantly with dental anxiety. Patients with medical history were found to be more anxious than normal patients. Patients with higher anxiety values were less satisfied with the treatment. Lastly, subjects with higher general anxiety showed greater values on the dental anxiety scale. Clinical significance: The assessment of dental anxiety will help the prosthodontist in the management of anxious patients and secondly to provide evidence-based research into this psychological construct which has been shown to predict dental avoidance. Keywords: Dental anxiety, Denture satisfaction, Completely edentulous patients. How to cite this article: Shrivastava R, Srivastava R, Shigli K, Prashanth MB, Kumaraswamy BN, Nethravathi TD. Assessment of Dental Anxiety and its Correlation with Denture Satisfaction in Edentulous Patients. J Contemp Dent Pract 2012;13(3):257-260. Source of support: Nil Conflict of interest: None declared.