• Kyungpook Mathematical Journal
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• v.62 no.1
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• pp.119-132
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• 2022

Virotherapy is an effective method for the treatment of cancer. The oncolytic virus specifically infects the lyse cancer cell without harming normal cells. There is a time delay between the time of interaction of the virus with the tumor cells and the time when the tumor cells become infectious and produce new virus particles. Several types of viruses are used in virotherapy and the delay varies with the type of virus. This delay can play an important role in the success of virotherapy. Our present study is to explore the impact of this delay in cancer virotherapy through a mathematical model based on delay differential equations. The partial success of virotherapy is guarenteed when one gets a stable non-trivial equilibrium with a low level of tumor cells. There exits Hopf-bifurcation by considering the delay as bifurcation parameter. We have estimated the length of delay which preserves the stability of the non-trivial equilibrium point. So when the delay is less than a threshold value, we can predict partial success of virotherapy for suitable sets of parameters. Here numerical simulations are also performed to support the analytical findings.

• Advances in nano research
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• v.16 no.1
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• pp.53-69
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• 2024

Advancements in the technology of building materials has led to diverse applications of nanomaterials with the aim to monitor concrete structures. While there are myriad instances of the use of nanoparticles in building materials, the production of smart nano cement-composites is often expensive. Thereupon, this research aims to discover a sustainable nanomaterial from tyre waste using the pyrolysis process as part of the green manufacturing circle. Here, Nano Structure Tyre-Char (NSTC) is introduced as a zero-dimension carbon-based nanoparticle. The NSTC particles were characterized using various standard characterization techniques. Several salient results for the NSTC particles were obtained using microscopic and spectroscopic techniques. The size of the particles as well as that of the agglomerates were reduced significantly using the milling process and the results were validated through a scanning electron microscope. The crystallite size and crystallinity were found to be ~35nm and 10.42%, respectively. The direct bandgap value of 5.93eV and good optical conductivity at 786 nm were obtained from the ultra violet visible spectroscopy measurements. The thermal analysis reveals the presence of a substantial amount of carbon, the rate of maximum weight loss, and the two stages of phase transformation. The FT-Raman confirms the presence of carboxyl groups and a ID/IG ratio of 0.83. Water contact angle around 140° on the surface implies the highly hydrophobic nature of the material and its low surface energy. This characteristic process assists to obtain a sustainable nanomaterial from waste tyres, contributing to the development of a smart building material.

• Advances in nano research
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• v.16 no.5
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• pp.459-472
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• 2024

Nanotechnology is a popular field in the construction industry due to its multiple functions. It mitigates CO₂ emissions and enhances the desirable properties of concrete by replacing small amounts of cement with supplements. This study assess the sustainability impact of using two different nanoparticles partially replacing the cement with 0.3%, 0.6%, 1.0% of nano silica (NS) and 0.03%, 0.045%, 0.06% of Multi-Walled Carbon Nanotubes (MWCNT) in the green concrete mix developement. Nano-sized fragments at the atomic scale tends to modify the properties of concrete. Concrete may increase its strength, durability by adding nanocomposite materials, which will decrease the amount of nano and micropores in structural parts. The strength of the structural elements can be greatly improved and allowing them to withstand higher loads and resist deformation. It improved durability properties by 64.8% in water absorption, 56.4% in acid attack, 78.1% in sulphate attack, and 53.4% in chloride attack. There was an improvement in compressive strength of 37% and split tensile strength of 90%. SEM, FTIR, and XRD investigations have used to look at the microstructural characteristics of nanoconcrete dictated the microstructure characteristics may be made more consistent and dense by adding nanocomposite materials.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4193-4198
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• 2015

Background: Globally, retinoblastoma is the most common primary intraocular malignancy occurring in children. This paper documents the recent incidence rates of retinoblastoma by age and sex groups from the Population Based Cancer Registries (PBCRs) of Bangalore, Mumbai, Chennai, Delhi and Kolkata using the data from the National Cancer Registry Programme. Materials and Methods: Relative proportions, sex ratio, method of diagnosis, and incidence rates (crude and age standardized) for each PBCR and pooled rates of the five PBCRs were calculated for the years 2005/06 to 2009/10. Standard errors and 95% confidence limits of ASIRs by sex group in each PBCR were calculated using the Poisson distribution. Standardised rate ratios of ASIR by sex group and rate ratios at risk were also calculated. Results: The maximum retinoblastoma cases were in the 0-4 age group, accounting for 78% (females) and 81% (males) of pooled cases from five PBCRs. The pooled crude incidence rate in the 0-14 age group was 3.5 and the pooled ASIR was 4.4 per million. The pooled ASIR in the 0-4, 5-9 and 10-14 age group were 9.6, 2.0 and 0.1 respectively. The M/F ratio in Chennai (1.9) and Bangalore PBCRs (2.0) was much higher than the other PBCRs. Among the PBCRs, the highest incidence rate in 0-4 age group was found in males in Chennai (21.7 per million), and females in Kolkata (18.9 per million). There was a distinct variation in incidence rates in the PBCRs in different geographic regions of India.

• Research in Mathematical Education
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• v.9 no.1 s.21
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• pp.11-24
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• 2005

Problem solving is an important aspect of learning mathematics and has been extensively researched into by mathematics educators. In this paper we analyze the difficulties students encounter in various steps involved in solving problems involving physical and geometrical applications of mathematical concepts. Our research shows that, generally students, in spite of possessing adequate theoretical knowledge, have difficulties in identifying the hidden data present in the problems which are crucial links to their successful resolutions. Our research also shows that students have difficulties in solving problems involving constructions and use of symmetry.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6245-6250
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• 2012

Background: With increase in life expectancy, adoption of newer lifestyles and screening using prostate specific antigen (PSA), the incidence of prostate cancer is on rise. Globally prostate cancer is the second most frequently diagnosed cancer and sixth leading cause of cancer death in men. The present communication makes an attempt to analyze the time trends in incidence for different age groups of the Indian population reported in different Indian registries using relative difference and regression approaches. Materials and Methods: The data published in Cancer Incidence in Five Continents for various Indian registries for different periods and/or publications by the individual registries served as the source materials. Trends were estimated by computing the mean annual percentage change (MAPC) in the incidence rates using the relative difference between two time periods (latest and oldest) and also by estimation of annual percentage change (EAPC) by the Poisson regression model. Results: Age adjusted incidence rates (AAR) of prostate cancer for the period 2005-2008 ranged from 0.8 (Manipur state excluding Imphal west) to 10.9 (Delhi) per $10^5$ person-years. Age specific incidence rates (ASIR) increased in all PBCRs especially after 55 years showing a peak incidence at +65 years clearly indicating that prostate cancer is a cancer of the elderly. MAPC in crude incidence rate(CR) ranged from 0.14 (Ahmedabad) to 8.6 (Chennai). Chennai also recorded the highest MAPC of 5.66 in ASIR in the age group of 65+. Estimated annual percentage change (EAPC) in the AAR ranged from 0.8 to 5.8 among the three registries. Increase in trend was seen in the 55-64 year age group cohort in many registries and in the 35-44 age group in Metropolitan cities such as Delhi and Mumbai. Conclusions: Several Indian registries have revealed an increasing trend in the incidence of prostate cancer and the mean annual percentage change has ranged from 0.14-8.6.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.1073-1075
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• 2013

Background: In normal cells, activated epidermal growth factor receptor (EGFR) molecules are subjected to ubiquitination-mediated proteasome degradation pathway by c-Cbl, an ubiquitin ligase that checks uncontrolled proliferation. Hence expression of wild type c-Cbl molecule is essential to keep this degradation machinery in a functional state. Loss of expression or function of c-Cbl may consequently lead to sustained activation of EGFR and promote carcinogenesis, loss of function mutations in the c-Cbl gene already being reported in lung and hematopoietic cancers. However, the genetic status of c-Cbl in oral squamous cell carcinoma (OSCC) is not known. Hence in the present study we investigated the genomic DNA isolated from OSCC tissue biopsy samples for mutations in the RING finger domain coding region of c-Cbl gene, which has also been reported to be most frequently mutated in other cancers. Materials and Methods: Total genomic DNA isolated from thirty two post surgical OSCC tissue samples were amplified using primers flanking the exon 8 of c-Cbl gene that codes for the RING finger domain. The PCR amplicons were then resolved in a 1.2% agarose gel, purified and subjected to direct sequencing to screen for mutations. Results: The sequencing data of the thirty two OSCC samples did not identify mutations in the RING finger domain coding region of c-Cbl gene. Conclusions: To the best of our knowledge, this is the first time that the genetic status of c-Cbl gene in OSCC samples has been investigated. The present data indicates that genetic alteration of RING finger domain coding region of c-Cbl gene is relatively infrequent in OSCC samples.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5061-5065
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• 2013

Background: Oral tongue squamous cell carcinoma (OTSCC) is the most common cancer diagnosed within the oral cavity worldwide. Many studies in India report OTSCC ranking among the top two most common subsites within the oral cavity. India is often labeled the oral cancer capital of the world. The incidence of tongue cancers in the population-based cancer registry (PBCR) of Chennai is showing an increasing trend. A majority of the oral cavity cancers (85%) in our cancer center present in advanced stages (III and IV). In contrast, early tongue cancers (stages I and II) constitute nearly 45% of all OTSCCs. Aim: The aim of this study was to analyze the clinical profile and epidemiological trends in our early stage tongue cancer patients with an emphasis on tobacco and alcohol habits. Materials and Methods: This retrospective analysis was based on a prospectively collected database of 458 consecutive early stage OTSCC in-patients at a tertiary care oncology centre in Chennai between 1995 and 2008. Results: Our study suggests that the earlier trends have clearly changed whereby nearly half of our patients are now never-tobacco users. The findings of the study indicate that a majority of the patients were never alcohol users (86.4%) and nearly half of them were never tobacco users (49.3%), and they had the best survival outcomes. This increasing trend of OTSCC among non-tobacco users is in contrast to our earlier experience of tongue cancer more than five decades ago.The median age of patients in our study was 53.3 years; the male to female ratio was approximately 2:1. The median follow up for the 458 patients was 53 months. Conclusions: Our study importantly as well as interestingly shows a conspicuous absence of association with the traditional risk factors, tobacco and alcohol.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.35-41
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• 2017

Materials exposed to outside will deteriorate due to various weathering factors such as sunlight, heat, temperature, humidity and so on. Therefore, predicting speed of degradation and life time is a very important issue. This research uses retro-reflective sheets with white and green which are most commonly used colors to conduct the outdoor exposure test and acceleration test of xenon arc in Arizona state in the United States, Chennai in India, Sanary in France and Seosan in Korea to measure the reflective performance of retro-reflection. The accelerated factor was obtained by using regression analysis through reflective values obtained from the acceleration test of xenon arc from Seosan area. Also, by using solar uv program, the accelerated factor of various climate regions were obtained and it was confirmed that the accelerated factor of Senary was 1.04, Arizona 1.82, Chennai 1.92 times higher than that of Seosan.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1886-1900
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• 2018

This paper proposes a confronting feedback control structure and controllers for positive output elementary super lift Luo converters (POESLLCs) working in discontinuous conduction mode (DCM). The POESLLC offers the merits like high voltage transfer gain, good efficiency, and minimized coil current and capacitor voltage ripples. The POESLLC working in DCM holds the value of not having right half pole zero (RHPZ) in their control to output transfer function unlike continuous conduction mode (CCM). Also the DCM bestows superlative dynamic response, eliminates the reverse recovery troubles of diode and retains the stability. The proposed control structure involves two controllers respectively to control the voltage (outer) loop and the current (inner) loop to confront the time-varying ON/OFF characteristics of variable structured systems (VSSs) like POESLLC. This study involves two different combination of feedback controllers viz. the proportional integral controller (PIC) plus sliding mode controller (SMC) and the fuzzy logic controller (FLC) plus SMC. The state space averaging modeling of POESLLC in DCM is reviewed first, then design of PIC, FLC and SMC are detailed. The performance of developed controller combinations is studied at different working states of the POESLLC system by MATLAB-Simulink implementation. Further the experimental corroboration is done through implementation of the developed controllers in PIC 16F877A processor. The prototype uses IRF250 MOSFET, IR2110 driver and UF5408 diodes. The results reassured the proficiency of designed FLC plus SMC combination over its counterpart PIC plus SMC.