Effect of adaptation of acidothiobacillus ferrooxidans on ferrous oxidation and nickel leaching efficiency

Studies were carried out on ferrous oxidation and bacterial leaching of copper flotation concentrate to selectively leach nickel by two strains of Acidothiobacillus ferrooxidans. However, slower growth rates of these strains have led to prolonged lag periods during leaching process with low nickel recovery. Hence, attempts were made to adapt these strains to high concentrations of copper salt, nickel salt, mixture of copper and nickel salts and flotation concentrate which would facilitate the preferential leaching of Ni containing pentlandite phase from a floatation concentrate with chalcopyrite phase in predominance. When unadapted strains of Tf were replaced with adapted strains, the lag period during leaching process was drastically declined with immediate resurgence of pH fall indicating biologically produced acid. Cells adapted to metals and concentrate has shown positive effect on oxidizing ability of pyrite and nickel leaching efficiency. Unadapted Tf-44 and Tf-231 strains have shown selective leaching of nickel (55% and 49.7%) while the leachabilities obtained with adapted strains were 80% and 83.5% respectively

Comparative evaluation of implant designs influence of diameter, length and taper on stress and strain in the mandibular segment: A three dimensional Finite Element Analysis

INTRODUCTION: Success or failure of dental implants depends on the amount of stress transferred to the surrounding bone. Increased amount of loading to bone through implant cause failure, whereas decrease in amount of loading to bone causes improved success rate of implants. Biomechanical interaction between implant and bone decides the long term function or prognosis of dental implant system. AIM AND OBJECTIVES: 1. To evaluate the influence of implant length and diameter on stress distribution. 2. To understand the stress distribution around bone implant interface. 3. To understand the response of bone, under axial and non-axial loading conditions. MATERIALS AND METHODS: Finite element 3D mandibular model was made using CBCT of patient with completely edentulous mandible and in that model five posterior bone segments were selected. Nobel Replace Select Tapered implant with diameter and length 3.5x10mm, 4.3x10mm, 3.5x11.5mm and 4.3x11.5mm respectively were selected and three dimensionally modelled using Creo 2.0 parametric Pro/E software. Bone and implant models were assembled as 20 models and finite element analysis was done using ANSYS workbench v17.0 under axial and non-axial loads. RESULT: Under axial load and non-axial loads 3.5x10mm implant showed maximum von mises stress and strain in both cortical and cancellous bone whereas implant with diameter and length 4.3x11.5mm showed minimum von mises stress and strain in both cortical and cancellous bone. CONCLUSION: In axial and non-axial loads amount of stress distribution around implant and bone interface is influenced by diameter and length of implant in cortical and cancellous bone respectively. Increased diameter of the implant produces the minimum stress in cortical bone. Increased length of the implant produces the minimum stress in cancellous bone

Study on antibiotic use among geriatric patients based on anatomical therapeutic classification or defined daily dose methodology and world health organization-essential medicine list access, watch and reserve concept in tertiary care hospital of South India

Background: Geriatric patients are more vulnerable to infections and need special consideration on antibiotic use. Resistance to antibiotics among infectious bacteria has developed within a short span. There is a direct correlation between the consumption of antibiotics and the development of resistance. And surprisingly very few literatures were available on antibiotic consumption in geriatric population using defined daily dose (DDD) concept which paved the idea to conduct this study.Methods: A prospective observational study was carried out from November 2018 to April 2019. A total of 206 prescriptions of elderly patients were included in the study. The antibiotics were categorized by anatomical therapeutic classification (ATC) and DDD indicator/1000 inhabitants/day (DID) was used to figure out antibiotic consumption.Results: About 25.2% of patients were treated with antibiotics for respiratory tract infections. The patients received antibiotics empirically (53.8%) and without bacteriological investigation (58.73%). The overall consumption of antibiotics was 20.47 DID in which oral antibiotics was (8.5 DID) 42% and parenteral antibiotics (11.8 DID) 58%. Cephalosporins was observed to be the most consumed antibiotics (33.2%), specifically cefotaxime (14.6%) and ceftriaxone (12.6%). Moreover, 54.4% of antibiotics consumed from watch category of World Health Organisation (WHO) essential medicines list (EML) which was completely against WHO standard proportion.Conclusions: Higher consumption of cephalosporins, which falls into watch category was analysed in geriatric patients. These broad-spectrum antibiotics have high potential to develop antimicrobial resistance. A strict antibiotic policy is needed to be framed that enhance rational prescribing practices in geriatrics

Morphologic and morphometric analysis of glenoid cavity of human scapula

Background: To study the morphometry and morphology of glenoid cavity of dried scapula bone and in CT scan of glenoid cavity. The present study aimed at calculating three dimensions i.e. vertical diameter, horizontal diameter of the upper segment and horizontal diameter of the lower segment of the glenoid cavity and describing the incidence of its different shapes.Methods: This study was done on 100 dry, unpaired adult human scapulae of unknown sex. 50 scapulae belongs to right side and 50 scapulae belongs to left side obtained from Department of Anatomy, SRM Medical College and Research Institute. The above mentioned diameters are measured using Vernier caliper and the mean dimensions are calculated, morphological variations are studied. 3D CT images of scapulae, obtained from Department of Radiology, SRM Medical college and Hospital, Potheri, were also analysed.Results: In the current study, various dimensions and incidence of various shapes of glenoid cavity were measured. The incidence of both pear and inverted comma shape in right side is greater than in left whereas the incidence of oval shape in left side is greater than right side. The SI diameter of right glenoid is greater than the left, which is statistically significant. The Antero-posterior diameters (AP-1, AP-2, AP-3) of right glenoid is greater than the left, but not statistically significant.Conclusions: The knowledge of the above said variations of glenoid cavity is important in manufacturing the glenoid component of shoulder prosthesis, repair of Bankart’s lesion, procedures like posterior glenoid osteotomy