Influence of jaw tracking in intensity-modulated and volumetric-modulated arc radiotherapy for head and neck cancers:

Karthick Raj Mani,Sagar Upadhayay,K. J. Maria Das 대한방사선종양학회 2017 Radiation Oncology Journal Vol.35 No.1

Purpose: To Study the dosimetric advantage of the Jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for Head and Neck Cancers. Materials and Methods: We retrospectively selected 10 previously treated head and neck cancer patients stage (T1/T2, N1, M0) in this study. All the patients were planned for IMRT and VMAT with simultaneous integrated boost technique. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) technique by keeping the same constraints and priorities for a particular patient. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without JT for all the patients. Results: The conformity index average of all patients followed by standard deviation (x¯ ± σx¯ ) of the JT-IMRT, SJ-IMRT, JT-VMAT, and SJ-VMAT were 1.72 ± 0.56, 1.67 ± 0.57, 1.83 ± 0.65, and 1.85 ± 0.64, and homogeneity index were 0.059 ± 0.05, 0.064 ± 0.05, 0.064 ± 0.04, and 0.064 ± 0.05. JT-IMRT shows significant mean reduction in right parotid and left parotid shows of 7.64% (p < 0.001) and 7.45% (p < 0.001) compare to SJ-IMRT. JT-IMRT plans also shows considerable dose reduction to thyroid, inferior constrictors, spinal cord and brainstem compared to the SJ-IMRT plans. Conclusion: Significant dose reductions were observed for critical structure in the JT-IMRT compared to SJ-IMRT technique. In JTVMAT plans dose reduction to the critical structure were not significant compared to the SJ-IMRT due to relatively lesser monitor units.

A Multi-Inlet Microfluidic Nozzle Head with Shape Memory Alloy-Based Switching for Biomaterial Printing with Precise Flow Control

Karthick Mani,Wei-Chen Lin,Chun-Fang Wang,Bivas Panigrahi,Yong-Jin Wu,Cheng-Lung Wu,Chia-Yuan Chen 한국바이오칩학회 2020 BioChip Journal Vol.14 No.4

3D bioprinting is one of the rapidly evolving fields of tissue engineering where microengineering meets cells biology within an unprecedented precision to construct tissue structures of various forms with complexity. However, enabling simultaneous printing of heterogeneous biomaterial along with scaffold components through the currently available printers is still considered as a major challenge due to the lack of instrumentation. Flow control is one of the major issues associated with the process. In this aspect, a microfluidic nozzle head equipped with two shape-memory alloy (SMA) actuators was proposed and integrated with a commercially available 3D printer to assist the biomaterial printing in a more systematic manner. The SMA actuator restrains the amount of flows for fabricating the desired scaffold components. Experimental results illustrated that the use of SMA actuator ensued a rapid and precise flow control of biomaterial and can further facilitate to maintain the width of any printed structures. As a proof of concept for the profound biomedical applications with the present manufacturing configuration, a 3D printed hydrogel platform was fabricated with demonstrated characters for later cell seeding after the printing further opens a new chapter in terms of biomaterial printing.

Development of water-repellent cement mortar using silane enriched with nanomaterials

Karthick, Subbiah,Park, Dong-Jin,Lee, Yun Su,Saraswathy, Velu,Lee, Han-Seung,Jang, Hyun-O,Choi, Hyun-Jun Elsevier 2018 Progress in organic coatings Vol.125 No.-

<P><B>Abstract</B></P> <P>The exposure of reinforced concrete structures to freezing temperatures during winters can create internal stresses and surface microcracks in concrete owing to tiny ice crystal formations in the pores of concrete structures. Thus, in the present study, superhydrophobic surfaces were created on concrete by spraying and admixing superhydrophobic materials, comprising 1H,1H,1H,2H-perfluorodecyltriethoxysilane (PFDTS) with nano TiO<SUB>2</SUB> and SiO<SUB>2</SUB> inclusions, with cement mortar. TiO<SUB>2</SUB> nanomaterials were synthesized using ginger (<I>Zingiber officinale</I>) as a bio-template. The PFDTS enriched with nanomaterials (PFDTS-NM) was admixed with cement mortar during casting and was spray-coated on the cement mortar surface after casting. The spray-coated and admixed cement mortar sample surfaces were characterized by XRD, SEM/EDAX, and UV–vis spectroscopy, and their water-repellent properties were evaluated by measuring the contact angles (CA) and conducting water absorption and freeze-thawing tests. The pore size distributions of the samples before and after freeze-thawing were evaluated by mercury intrusion porosimetry (MIP). The results confirm the presence of PFDTS with inclusions of rod-shaped TiO<SUB>2</SUB> nanoparticles on the concrete surface. Further, the CAs of normal, coated, and admixed cement mortar surfaces were found to be 45.5°, 162.3°, and 162.0°, respectively. The spray-coated and admixed concrete can be used to form superhydrophobic surfaces on concrete structures to reduce water absorption and increase the durability of cement mortar.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TiO<SUB>2</SUB> was successfully synthesized by bio-template synthesis method. </LI> <LI> PFDTS-enriched with nanomaterials (TiO<SUB>2</SUB> and SiO<SUB>2</SUB>) was developed as a superhydrophobic surface on cement mortar. </LI> <LI> PFDTS-enriched-nanomaterial exhibit superhydrophobic surface with UV-shielding ability. </LI> <LI> The water-contact angles of coated and admixed cement mortar were 162.3° and 162.0° respectively. </LI> <LI> The PFDTS-enriched-nanomaterial has better freeze-thawing barrier performance than normal cement mortar. </LI> </UL> </P>

Estimation of the reproduction number and early prediction of the COVID-19 outbreak in India using a statistical computing approach

Karthick Kanagarathinam,Kavaskar Sekar 한국역학회 2020 Epidemiology and Health Vol.42 No.-

Coronavirus disease 2019 (COVID-19), which causes severe respiratory illness, has become a pandemic. The World Health Organization has declared it a public health crisis of international concern. We developed a susceptible, exposed, infected, recovered (SEIR) model for COVID-19 to show the importance of estimating the reproduction number (R0). This work is focused on predicting the COVID-19 outbreak in its early stage in India based on an estimation of R0. The developed model will help policy-makers to take active measures prior to the further spread of COVID-19. Data on daily newly infected cases in India from March 2, 2020 to April 2, 2020 were to estimate R0 using the earlyR package. The maximum-likelihood approach was used to analyze the distribution of R0 values, and the bootstrap strategy was applied for resampling to identify the most likely R0 value. We estimated the median value of R0 to be 1.471 (95% confidence interval [CI], 1.351 to 1.592) and predicted that the new case count may reach 39,382 (95% CI, 34,300 to 47,351) in 30 days.

Synthesis of nano-bound microsphere Co3O4 by simple polymer-assisted sol-gel technique

Karthick, S. N.,Hemalatha, K. V.,Justin Raj, C.,Kim, Hee Je,Yi, Moonsuk Springer-Verlag 2013 Journal of nanoparticle research Vol.15 No.3

염화물에 노출된 콘크리트 기공 내에 솔방울 추출물의 부식 방청 특성

카식수비아 ( Karthick Subbiah ),박태준 ( Park Taejoon ),이한승 ( Lee Han Seung ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.1

The corrosion inhibition properties of conifer cone (Pinus resinosa) extract were studied in synthetic concrete pore solutions (SCPS) with and without chloride environments by electrochemical methods. The electrochemical impedance spectroscopy (EIS) revealed that the conifer cone (CC) extract showed promising inhibition behavior by diminishing the corrosion rate of steel rebar both solutions i.e. with and without chloride. The extract of conifer cone hinders the corrosion reaction between steel rebar and aggressive ions. Further, it can be verified that the up to 1000mg.L-1 of CC extract can able to reduce the corrosion rate of steel rebar in chloride contaminated concrete.

모의 콘크리트 환경에서 강철 철근의 부식을 모니터링하기 위한 현장 고체 기준 전극 평가

카르틱수비아 ( Karthick Subbiah ),박태준 ( Park Taejoon ),이한승 ( Lee Han-seung ) 한국건축시공학회 2023 한국건축시공학회 학술발표대회 논문집 Vol.23 No.1

The solid-state reference electrodes made of polyaniline-coated MnO2 (SSRE-PAM) and their electrochemical characteristics were studied in simulated concrete pore solutions (SCPS) containing 0 and 3.5% NaCl. Saturated calomel electrodes (SCE) have been used to conduct electrochemical studies on the stability behavior of SSRE-PAM. Open circuit potential (OCP) and potentiodynamic polarization techniques were used to assess the corrosion performance of steel rebar exposed in SCPS with 0 and 3.5% NaCl using SSRE-PAM. The results demonstrate that the SSRE-PAM was capable of identifying steel rebar in a concrete environment that was either passive or active. Potentiodynamic polarization parameters such as Ecorr and Icorr for steel rebar in SCPS containing 0 and 3.5%)NaCl are greater than that of the passive condition (0% NaCl). All the studies validate the importance of using SSRE-PAM for corrosion monitoring applications in concrete structures.

해양 환경에서 매립형 고체 기준 전극을 사용한 철근 부식 조사

카르틱수비아 ( Karthick Subbiah ),박태준 ( Taejoon Park ),이한승 ( Han-seung Lee ) 한국건축시공학회 2022 한국건축시공학회 학술발표대회 논문집 Vol.22 No.1

Reinforced concrete (RC) structures play a significant role in the construction industries. An embeddable solid-state reference electrode (ESSRE) was used to evaluate the corrosion status of steel rebar in the concrete of various cover thicknesses that exposed to the maritime environment (3.5 % NaCl) in this study. From the open circuit potential measurement (OCP), the passive state, the corrosion uncertainty, and the 90% probability of corrosion state of the steel rebars in the concrete were monitored by ESSRE. From the electrochemical impedance spectroscopy (EIS) method, severe corrosion was observed at the exposure period of 1510, 1847, 2350, and 3020 h for C10, C15, C20, and C30 concrete, respectively. The results confirm that the ESSRE can be useful to identify the corrosion occurrence and severe corrosion of steel rebar embedded in different cover depth concrete structures.

A Study on the Role of Accommodation for the Promotion of Domestic Tourism in Tamilnadu

( K. Karthick ),( M. K. Ganesh ) 한국문화관광학회 2018 문화관광연구 Vol.20 No.2

At present, tourism in Tamil Nadu is capable of attracting more tourists in its folds particularly in respect of attracting domestic tourists. The above picture is highly apparent from viewpoints of the local people, domestic tourists and accommodation providers. In Tamil Nadu, participation in tourism-related activities is seen to be more among local people as well as among hoteliers. Most of the hoteliers in various regions of tourism importance under study provide most of the facilities required for tourists’ less than one roof. That is, they provide facilities such as restaurant, car rentals, laundry and doctors on call for tourists

Influence of jaw tracking in intensity-modulated and volumetric-modulated arc radiotherapy for head and neck cancers: a dosimetric study

Mani, Karthick Raj,Upadhayay, Sagar,Das, K.J. Maria The Korean Society for Radiation Oncology 2017 Radiation Oncology Journal Vol.35 No.1

Purpose: To Study the dosimetric advantage of the Jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for Head and Neck Cancers. Materials and Methods: We retrospectively selected 10 previously treated head and neck cancer patients stage (T1/T2, N1, M0) in this study. All the patients were planned for IMRT and VMAT with simultaneous integrated boost technique. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) technique by keeping the same constraints and priorities for a particular patient. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without JT for all the patients. Results: The conformity index average of all patients followed by standard deviation (${\bar{x}}{\pm}{\sigma}_{\bar{x}}$) of the JT-IMRT, SJ-IMRT, JT-VMAT, and SJ-VMAT were $1.72{\pm}0.56$, $1.67{\pm}0.57$, $1.83{\pm}0.65$, and $1.85{\pm}0.64$, and homogeneity index were $0.059{\pm}0.05$, $0.064{\pm}0.05$, $0.064{\pm}0.04$, and $0.064{\pm}0.05$. JT-IMRT shows significant mean reduction in right parotid and left parotid shows of 7.64% (p < 0.001) and 7.45% (p < 0.001) compare to SJ-IMRT. JT-IMRT plans also shows considerable dose reduction to thyroid, inferior constrictors, spinal cord and brainstem compared to the SJ-IMRT plans. Conclusion: Significant dose reductions were observed for critical structure in the JT-IMRT compared to SJ-IMRT technique. In JT-VMAT plans dose reduction to the critical structure were not significant compared to the SJ-IMRT due to relatively lesser monitor units.