Comparison of Three Different Options for C7 Posterior Vertebral Anchor in the Indian Population—Lateral Mass, Pedicle, and Lamina: A Computed Tomography-Based Morphometric Analysis

Vibhu Krishnan Viswanathan,Surabhi Subramanian,Sushma Viswanathan 대한척추외과학회 2018 Asian Spine Journal Vol.12 No.4

Study Design: Radiological cohort study. Purpose: The options of posteriorly stabilizing C7 vertebra include using lateral mass, pedicle or lamina, as bony anchors. The current study is a computed tomography (CT)-based morphometric analysis of C7 vertebra of 100 Indian patients and discusses the feasibility of these different techniques. Overview of Literature: C7 is a peculiar vertebra with unique anatomy, which poses challenges for each of these fixation modalities. There are no reports available in the literature, which discuss and compare the feasibility of diverse posterior C7 fixation techniques in Indian population. Methods: We included 100 consecutive cervical spine CT scans of Indian patients performed between July 2016 and September 2016. We excluded CT scans with any significant congenital anomaly or other pathological lesions of C7 and patients with non-Indian ethnicity. Regarding screw placement, we assessed and studied various dimensions of the C7 lateral mass, pedicles, and laminae in relevant sections. Results: The mean age of our patients was 49.5±16.1 years. We included 56 male and 44 female patients. The mean anteroposterior and mediolateral dimensions of the lateral mass were 11.38±1.76 and 12.91±1.82 mm, respectively. The mean length of the lateral mass screw (Magerl technique) was 12.17±1.9 mm; 92% of patients could accommodate a lateral mass screw at least 10-mm long (unicortical), whereas 48% could accommodate a screw (unicortical) longer than 12 mm. Foramen transversarium was found in 30.5% of lateral masses. The mean outer and inner cortical widths of the pedicles were 6.5±0.71 mm and 3.72±0.61 mm, respectively. Approximately 58% of pedicles could accommodate 3.5-mm screws (based on the inner cortical pedicle width). The outer cortical and inner cortical widths of the laminae were 6.21±1.2 mm and 3.23±0.9 mm, respectively. Subsequently, 37% of the laminae could accommodate 3.5-mm screws. The mean angle of intralaminar screw trajectory was 50.7°±5.1°, and the mean length of the intralaminar screw was 32.6±3.05 mm. In addition, 96.4% and 60.7% of male patients could accommodate lateral mass screws longer than 10 mm and 12 mm, respectively. However, only 86.4% and 31.8% of female patients could accommodate 10- and 12-mm long lateral mass screws, respectively. Furthermore, 75% of male patients and 36% of female patients had pedicles that could accommodate 3.5-mm diameter screws, and 48.2% of male patients had laminae that could accommodate 3.5-mm screws; however, only 22.7% of female patients could accommodate 3.5-mm laminar screws. Conclusions: Based on our CT-guided morphometric analysis, 92% and 48% of Indian patients could accommodate at least 10- and 12-mm long lateral mass screws, and 58% of pedicles and 37% of laminae could accommodate 3.5-mm screws. Thus, lateral mass screws (between 10- and 12-mm long) seem to be the safest feasible option for C7 fixation. In case of the need for an alternative mode of stabilization (pedicle or intralaminar screw), particularly in female patients, careful preoperative planning with a CT scan is of utmost importance.

Performance and evaluation of MoS2 based machining using PVD-TiAlN coated tool

Viswanathan Sivaraman,Subramanian Prakash 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.9

A recent trend on turning of difficult-to-machine (DTM) materials using environmentally friendly vegetable oil has became popular due to its immense machinability aids. Conventional cutting oils fail to give cooling/lubrication at higher cutting speed-feed combination and create environmental pollution. The present work investigated the effect of molybdenum disulphide nanoparticle (nMoS 2 ) dispersed in castor oil, as a cutting fluid, sprayed using minimum quantity lubrication (MQL) technique on turning of AISI O1 cold worked tool steel. The machining was carried out by varying the speed ranging from 110-170 m/min, a feed rate of 0.02-0.08 mm/rev and depth of cut of 0.7 mm. PVD-TiAlN coated tungsten carbide insert was used for the experimentation. The experimental results of nMQL condition were compared with the dry and wet condition. The results proved that application nMQL has given 15-49 % enhanced tool life with better surface finish as compared with dry and wet condition, respectively. No major phase change occurs in nMQL when compared with other conditions because of their low cutting temperature.

Organic conversion coatings for magnesium and its alloys

Viswanathan S. Saji 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.75 No.-

The currently employed inorganic conversion coatings are unattractive and their use is restricted due totoxicity, non-biodegradability and high cost. Conversion coatings based on environmentally friendly,economic and biodegradable organic compounds is a promising alternative approach. These compoundswith surface chelating functional groups can effectively bond with the magnesium/surface hydroxidelayer and at the same time can provide anchoring groups for the polymer overcoat. They can act as apotential host for nanoreservoirs with loaded inhibitors for active self-healing corrosion protection. Thisreview provides a comprehensive account of the organic conversion coatings for magnesium and itsalloys.

The Effect of Post-Heat Treatment on the Ion Dissolution Behavior of Nanotubular Titanium Alloys

Viswanathan S. Saji,최한철 대한금속·재료학회 2011 METALS AND MATERIALS International Vol.17 No.2

Recently, nanoscale tubular oxide layers on titanium alloys have attracted considerable research interest due to their potential application in various fields such as implant engineering, solar energy conversion, etc. In the present study, we have investigated the ion dissolution behavior of titanium alloys coated with a layer of nanotubular oxide in Ringer’s solution as a function of post-heat treatment temperature. The results of the study showed that post-heat treatment had significant influence on the ion dissolution behavior of nanotubular titanium alloys.

Free vibration of symmetric angle-ply laminated cylindrical shells of variable thickness

Viswanathan, K. K.,Lee, Jang Hyun,Aziz, Zainal Abdul,Hossain, I. Springer-Verlag 2011 Acta mechanica Vol.221 No.3

Axisymmetric vibrations of layered cylindrical shells of variable thickness using spline function approximation

Viswanathan, K.K.,Kim, Kyung Su,Lee, Jang Hyun,Lee, Chang Hyun,Lee, Jae Beom Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

Free axisymmetric vibrations of layered cylindrical shells of variable thickness are studied using spline function approximation techniques. Three different types of thickness variations are considered namely linear, exponential and sinusoidal. The equations of axisymmetric motion of layered cylindrical shells, on the longitudinal and transverse displacement components are obtained using Love's first approximation theory. A system of coupled differential equations on displacement functions are obtained by assuming the displacements in a separable form. Then the displacements are approximated using Bickley-spline approximation. The vibrations of two-layered cylindrical shells, made up of several types of layered materials and different boundary conditions are considered. Parametric studies have been made on the variation of frequency parameter with respect to the relative layer thickness, length ratio and type of thickness variation parameter.

Mechanical and Corrosion Resistance Properties of a Low Rigidity Quaternary Titanium Alloy for Biomedical Applications

Viswanathan S. Saji,Han-Cheol Choe,Yeong-Mu Ko 한국표면공학회 2008 한국표면공학회 학술발표회 초록집 Vol.2008 No.-

Electrophoretic (EPD) coatings for magnesium alloys

Viswanathan S. Saji 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Electrophoretic deposition (EPD) has been investigated extensively as an efficient and straightforwardsurface coating approach to enhance corrosion resistance, biocompatibility, bioactivity, wear resistance,anti-microbial qualities, and mechanical properties of magnesium (Mg) and its alloys. Here, we provide acomprehensive review of EPD coatings for Mg alloys. Reported works are classified based on the nanoparticlesused in the suspension, composite coating strategies, combined fabrication approaches, and applicationdomains. Future scopes of research also presented.

Effects of Feeding Different Protein Supplements on Digestibility, Nitrogen Balance and Calcium and Phosphorus Utilization in Sheep

Viswanathan, T.V.,Fontenot, J.P. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.5

Two metabolism trials were conducted with 24 wether lambs to investigate the effects of feeding crab meal and other protein supplements on N utilization, digestibility and Ca and P balance in sheep. The lambs (avg. BW, 25 kg) were randomly allotted to eight diets in each of two trials. The supplements were: i) none, negative control (NC); ii) soybean meal (SBM), control; iii) supplement based on industrial byproducts of both plant and animal origin (IPA); iv) experimental supplement based on byproducts of animal origin (ESA); v) hydrolyzed supplement No 4. (HESA); vi) commercial supplement based on animal protein (CS), $Pro-Lak^{(R)}$ vii) crab meal (CM); and viii) urea (U). The supplements supplied 33% of the total dietary N (CP, 9.8%; DM basis). Lambs fed the NC diet had lower (p<0.05) DM and OM digestibility. Lower (p<0.05) apparent absorption of N was recorded for the lambs fed the HESA and NC diets. Sheep fed CM had lower Ca absorption compared to SBM. Highest (p<0.05) P absorption was observed for lambs fed CS and CM and lowest for U and NC diets. Sheep fed CM had higher (p<0.05) total VFA concentration (65.7 ${\mu}mol/ml$), compared to those fed ESA, CS, and NC diets (47.3, 49.8, and 49.5 ${\mu}mol/ml$, respectively). Highest (p<0.05) ruminal $NH_3$ N (29.6 mg/dl) was observed in lambs fed the U diet, while those fed the NC diet had the lowest (p<0.05) average value (7.66 mg/dl). Lambs fed the U diet had the highest (p<0.05) blood urea N (10.67 mg/dl). The present study showed that N utilization of diets supplemented with experimental supplements based on feather meal and blood meal; commercial supplement based on animal protein, $Prolak^{(R)}$ supplement based on plant protein and blood meal; and crab meal are comparable with that of soybean meal.

Free vibration of symmetric angle-ply layered conical shell frusta of variable thickness under shear deformation theory

Viswanathan, K.K.,Javed, Saira,Aziz, Zainal Abdul Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.2

Free vibration of symmetric angle-ply layered conical shell frusta of variable thickness is analyzed under shear deformation theory with different boundary conditions by applying collocation with spline approximation. Linear and exponential variation in thickness of layers are assumed in axial direction. Displacements and rotational functions are approximated by Bickley-type splines of order three and obtained a generalized eigenvalue problem. This problem is solved numerically for an eigenfrequency parameter and an associated eigenvector of spline coefficients. The vibration of three and five-layered conical shells, made up of two different type of materials are considered. Parametric studies are made for analysing the frequencies of the shell with respect to the coefficients of thickness variations, length-to-radius ratio, length-to-thickness ratio and ply angles with different combination of the materials. The results are compared with the available data and new results are presented in terms of tables and graphs.