General Theorem for Explicit Evaluations and Reciprocity Theorems for Ramanujan-Göllnitz-Gordon Continued Fraction

SAIKIA, NIPEN Department of Mathematics 2015 Kyungpook mathematical journal Vol.55 No.4

In the paper A new parameter for Ramanujan's theta-functions and explicit values, Arab J. Math. Sc., 18 (2012), 105-119, Saikia studied the parameter $A_{k,n}$ involving Ramanujan's theta-functions ${\phi}(q)$ and ${\psi}(q)$ for any positive real numbers k and n and applied it to find explicit values of ${\psi}(q)$. As more application to the parameter $A_{k,n}$, in this paper we prove a new general theorem for explicit evaluation of Ramanujan-$G{\ddot{o}}llnitz$-Gordon continued fraction K(q) in terms of the parameter $A_{k,n}$ and give examples. We also find some new explicit values of the parameter $A_{k,n}$ and offer reciprocity theorems for the continued fraction K(q).

Polyolefin Based Copolymers as Matrix Component in Coir Fiber Reinforced Composites

Maitrayee Saikia,Nilakshi Kakati,Urmilla Baruah,Lachit Phukan,Prakash J. Saikia,Shashi D. Baruah 한국섬유공학회 2020 Fibers and polymers Vol.21 No.9

Natural fiber reinforced polymer composites have attracted much attention in global market as they possess muchadvantageous characteristics over conventional composite materials in terms of eco-friendliness, light weight, low cost, goodmechanical properties and biodegradability. Among natural fibers, the surface properties of coir fiber can be easily improvedwhen the fiber is reinforced with polymer matrix. Therefore, the aim of the present investigation is to develop a coir fibercomposite reinforced with polyolefin based copolymers (PCs) and investigate the influence of coir fiber loading onmechanical as well as on water absorption behavior of the composites. Three types of PCs were synthesized using differentcontrolled radical polymerizations (CRP) techniques and used as matrix in composite preparation. Poly(ethylene-co-butylmethacrylate) synthesized via dual concurrent atom transfer radical polymerization (ATRP)-reversible addition fragmentationchain transfer (RAFT) polymerization as well as RAFT mediated miniemulsion polymerization and poly(1-octene-co-butylmethacrylate) synthesized via RAFT polymerization were used as matrix component to prepare the composite materials. Theperformance evaluation of these PCs in the prepared composites was also compared. The composites were prepared usingcompression moulding method by reinforcing with 65, 70, 75 and 80 wt. % coirfiber loading. Analysis by universal testingmachine (UTM) showed that the tensile strength and flexural strength of composites were decreased with increase in the fiberloading. Highest tensile as well as flexural strength was observed for 65 wt. % coir fiber loading. Among the three types ofPCs matrixes, poly(ethylene-co-butyl mehacrylate) synthesized by RAFT mediated miniemulsion polymerization showedhighest tensile and flexural strengths in the prepared composite. PCs reinforced coir fiber composites showed the potentialadvantage over coir fiber composites with commercial Araldite 506 resin as matrix component in terms of tensile as well asflexural properties. The morphological study by scanning electron microscopy (SEM) analysis confirmed the good adhesionbetween the PCs matrixes and the coir fibers in the prepared composites. X-ray photoelectron spectroscopy (XPS) analysisdemonstrated significant changes occurred on the surface of coir fiber due to reinforcement of PCs matrixes and X-raydiffraction studies showed the amorphous natures of the composites without any crystallinity. Thermogravimetric analysisresults revealed that due to penetration of PCs matrix into the coir fiber, the thermal stability of composites were significantlyincreased. Furthermore, water absorption properties of composites were also investigated. Based on these results thesynthesized PCs/coir composite materials are found to be suitable for its use as hardboards and in different householdfurniture materials.

Polymorphisms in Heat Shock Proteins A1B and A1L (HOM) as Risk Factors for Oesophageal Carcinoma in Northeast India

Saikia, Snigdha,Barooah, Prajjalendra,Bhattacharyya, Mallika,Deka, Manab,Goswami, Bhabadev,Sarma, Manash P,Medhi, Subhash Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.18

Background: To investigate polymorphisms in heat shock proteins A1B and A1L (HOM) and associated risk of oesophageal carcinoma in Northeast India. Materials and Methods: The study includes oesophageal cancer (ECA) patients attending general outpatient department (OPD) and endoscopic unit of Gauhati Medical College. Patients were diagnosed based on endoscopic and histopathological findings. Genomic DNA was typed for HSPA1B1267 and HSPA1L2437 SNPs using the polymerase chain reaction with restriction fragment length polymorphisms. Results: A total of 78 cases and 100 age-sex matched healthy controls were included in the study with a male: female ratio of 5:3 and a mean age of $61.4{\pm}8.5years$. Clinico-pathological evaluation showed 84% had squamous cell carcinoma and 16% were adenocarcinoma. Dysphagia grades 4 (43.5%) and 5 (37.1%) were observed by endoscopic and hispathological evaluation. The frequency of genomic variation of A1B from wild type A/A to heterozygous A/G and mutant G/G showed a positive association [chi sq=19.9, p=<0.05] and the allelic frequency also showed a significant correlation [chi sq=10.3, with cases vs. controls, OR=0.32, $p{\leq}0.05$]. The genomic variation of A1L from wild T/T to heterozygous T/C and mutant C/C were found positively associated [chi sq=7.02, p<0.05] with development of ECA. While analyzing the allelic frequency, there was no significant association [chi sq=3.19, OR=0.49, p=0.07]. Among all the risk factors, betel quid [OR=9.79, Chi square=35.0, p<0.05], tobacco [OR=2.95, chi square=10.6, p<0.05], smoking [OR=3.23, chi square=10.1, p<0.05] demonstrated significant differences between consumers vs. non consumers regarding EC development. Alcohol did not show any significant association [OR=1.34, chi square=0.69, p=0.4] independently. Conclusions: It can be concluded that the present study provides marked evidence that polymorphisms of HSP70 A1B and HSP70 A1L genes are associated with the development of ECA in a population in Northeast India, A1B having a stronger influence. Betel quid consumption was found to be a highly significant risk factor, followed by smoking and tobacco chewing. Although alcohol was not a potent risk factor independently, alcohol consumption along with tobacco, smoking and betel nut was found to contribute to development of ECA.

Tax Cost: Does It Deter Foreign Direct Investment (FDI)?

Saikia Munmi 한국국제경제학회 2024 International Economic Journal Vol.38 No.1

Yes, it does. My study investigates the question, ‘does tax cost deter FDI?’ by employing a rich dataset of bilateral FDI between the OECD developed countries and developing countries. The argument posed in the study is – ‘tax cost deters FDI as it straightway reduces the profitability of multinational firms’. The contribution of the study to the empirical literature of international economics is noteworthy. It adds to the literature by estimating the partial effect of tax cost on FDI while drawing on the gravity framework as its analytical approach. By utilizing the empirical exercise, the study draws the inference that the tax cost indeed substantially deters FDI. Furthermore, the study explores – ‘how does parent’s tax system – the worldwide tax system and the territorial tax system affect the sensitivity of FDI to tax cost?’ The study affirms that FDI reacts differently depending on the parents’ tax system. The study also examines the effect of host-country differences on the responsiveness of FDI to tax cost. Additionally, the study also empirically validates the ‘regionalists’ argument’.

Ameliorative effects of Garcinia pedunculata fruit extract on adenine-induced chronic kidney disease in mice, and the role of Garcinol: relevance to hyperuricemia and urolithiasis

Saikia Rubul,Choudhury Shuvasish,Borah Anupom,Mazumder Muhammed Khairujjaman 경희대학교 융합한의과학연구소 2020 Oriental Pharmacy and Experimental Medicine Vol.20 No.2

With ageing of the global population, and increased prevalence of diabetes and hypertension, the incidences of chronic kidney disease (CKD) is also on the rise. We have recently demonstrated that high adenine diet leads to CKD with hyperuricemia, and deposition of uroliths of adenine and 2, 8-dihydroxyadenine. Production of uric acid and 2,8-dihydroxyadenine are catalyzed by xanthine oxidoreductase (XOR). The present study was undertaken to elucidate renoprotective potentials of aqueous fruit extract of Garcinia pedunculata (2% w/v mixed with drinking water) in animal model of CKD, in terms of serum parameters and urolithiasis. To develop the mice model, the mice were given high adenine (0.3% w/w) diet mixed with feed. Elevation in the levels of serum urea and uric acid, and renal histopathological changes were regarded as parameters to validate the model. Aqueous fruit extract of G. pedunculata significantly ameliorated the serum levels of urea and uric acid, and histological alterations. Since Garcinol is one of the principal constituents of the plant, computational modelling was performed to determine inhibitory potential of Garcinol on XOR. The computational modelling revealed that Garcinol may directly inhibit XOR by interacting with the active site of the enzyme. Our findings demonstrated that the fruit extract of G. pedunculata may ameliorate adenine-induced CKD in mice, in terms of haematological and histopathological changes, the mechanism of which has been proposed to be inhibition of XOR by Garcinol. Thus, the present study is important in the treatment paradigm of CKD as a whole, and urolithiasis and hyperuricemia in particular.

Tree Species Diversity and Its Population and Regeneration Status in Homegardens of Upper Assam, Northeast India

Saikia, P.,Khan, M.L. Institute of Forest Science 2016 Journal of Forest Science Vol.32 No.2

Study was conducted to investigate tree diversity and its population and regeneration status in homegardens of upper Assam, Northeast India through field study by quadrat method. A total of 154 tree species have been recorded from 135 studied homegardens under 109 genera 53 families. Most of these species (79%) are indigenous to our country, while the rest (21%) arealiens (naturalized and cultivated exotics) by origin. Tree species richness per homegarden varies greatly in different homegardens and is ranged from 5 to 52 tree species with a mean of 22 ($SE{\pm}0.58$). A. malaccensis is the most dominant tree species in the studied homegardens contributed 34% of the total tree density of the documented trees. The tree density is much higher with 4,259 individuals $ha^{-1}$ but, basal area ($36.32m^2ha^{-1}$) is very less. Based on the number of individuals present, very rare species is accounted for 10%, rare species 39%, common species 19%, dominants 14% and predominant species 18% in the present study. The population density of 154 tree species is 4,259 (individuals $ha^{-1}$) for adults (>3.18 cm DBH), 5,902 (individuals $ha^{-1}$) for saplings and 38,164 (individuals $ha^{-1}$) for seedlings. The density of seedlings>saplings>adults represents good regeneration status of tree species in studied homegardens. The population structure study showed that about 8% tree species have good regeneration status, 9% have fair regeneration status, 48% have poor regeneration status and 34% tree species have no regeneration. Study suggests that research and development action is needed to stimulate regeneration of those tree species which having high importance value indices but showing poor or no regeneration. Based on present observation, it can be conclude that homegarden can emerge as an effective means for both economic well-being and biodiversity conservation in upper Assam, Northeast India.

Influence of a reversible addition–fragmentation chain transfer agent in the dispersion polymerization of styrene

Saikia, Prakash J.,Lee, Jung Min,Lee, Byung H.,Choe, Soonja Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of polymer science Part A, Polymer chemist Vol.45 No.3

<P>Dispersion polymerization was applied to the controlled/living free-radical polymerization of styrene with a reversible addition–fragmentation chain transfer (RAFT) polymerization agent in the presence of poly(N-vinylpyrrolidone) and 2,2′-azobisisobutyronitrile in an ethanol medium. The effects of the polymerization temperature and the postaddition of RAFT on the polymerization kinetics, molecular weight, polydispersity index (PDI), particle size, and particle size distribution were investigated. The polymerization was strongly dependent on both the temperature and postaddition of RAFT, and typical living behavior was observed when a low PDI was obtained with a linearly increased molecular weight. The rate of polymerization, molecular weight, and PDI, as well as the final particle size, decreased with an increased amount of the RAFT agent in comparison with those of traditional dispersion polymerization. Thus, the results suggest that the RAFT agent plays an important role in the dispersion polymerization of styrene, not only reducing the PDI from 3.34 to 1.28 but also producing monodisperse polystyrene microspheres. This appears to be the first instance in which a living character has been demonstrated in a RAFT-mediated dispersion polymerization of styrene while the colloidal stability is maintained in comparison with conventional dispersion polymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 348–360, 2007</P> <B>Graphic Abstract</B> <P>Dispersion polymerization was applied to the controlled/living free-radical polymerization of styrene with a reversible addition–fragmentation chain transfer polymerization (RAFT) agent in the presence of poly(N-vinylpyrrolidone) and 2,2′-azobisisobutyronitrile in an ethanol medium. The effects of the polymerization temperature and the postaddition of RAFT on the polymerization kinetics, molecular weight, polydispersity index, particle size, and particle size distribution were investigated and found to be strongly dependent on both the temperature and postaddition of RAFT. <img src='wiley_img/0887624X-2007-45-3-POLA21834-gra001.gif' alt='wiley_img/0887624X-2007-45-3-POLA21834-gra001'> </P>

Role of Riboflavin in Induced Resistance against Fusarium Wilt and Charcoal Rot Diseases of Chickpea

Saikia Ratul,Yadav Mukesh,Varghese Saju,Singh Bhim Pratap,Gogoi Dip K,Kumar Rakesh,Arora Dilip K The Korean Society of Plant Pathology 2006 Plant Pathology Journal Vol.22 No.4

Riboflavin caused induction of systemic resistance in chickpea against Fusarium wilt and charcoal rot diseases. The dose effect of 0.01 to 20 mM riboflavin showed that 1.0 mM concentration was sufficient for maximum induction of resistance; higher concentration did not increase the effect. At this concentration, riboflavin neither caused cell death of the host plant nor directly affected the pathogen's growth. In time course observation, it was observed that riboflavin treated chickpea plants were inducing resistance 2 days after treatment and reached its maximum level from 5 to 7 days and then decreased. Riboflavin had no effect on salicylic acid(SA) levels in chickpea, however, riboflavin induced plants found accumulation of phenols and a greater activities of phenylalanine ammonia lyase(PAL) and pathogenesis related(PR) protein, peroxidase was observed in induced plant than the control. Riboflavin pre-treated plants challenged with the pathogens exhibited maximum activity of the peroxidases 4 days after treatment. Molecular weight of the purified peroxidase was 42 kDa. From these studies we demonstrated that riboflavin induced resistance is PR-protein mediated but is independent of salicylic acid.

Association of a p53 Codon 72 Gene Polymorphism with Environmental Factors and Risk of Lung Cancer: a Case Control Study in Mizoram and Manipur, a High Incidence Region in North East India

Saikia, Bhaskar Jyoti,Das, Mandakini,Sharma, Santanu Kumar,Sekhon, Gaganpreet Singh,Zomawia, Eric,Singh, Yanglem Mohen,Mahanta, Jagadish,Phukan, Rup Kumar Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.24

Background: A very high incidence of lung cancer is observed in Mizoram and Manipur, North East India. We conducted a population based case control study to establish associations of p53 codon 72 polymorphisms and interactions with environmental factors for this high incidence. Material and Methods: A total of 272 lung cancer cases and 544 controls matched for age (${\pm}5years$), sex and ethnicity were collected and p53 codon 72 polymorphism genotypes were analyzed using a polymerase chain based restriction fragment length polymorphism assay. We used conditional multiple logistic regression analysis to calculate adjusted odds ratios and 95% confidence intervals after adjusting for confounding factors. Results: p53 Pro/Pro genotype was significantly associated with increased risk of lung cancer in the study population (adjusted OR=2.14, CI=1.35-3.38, p=0.001). Interactions of the p53 Pro/Pro genotype with exposure to wood smoke (adjusted OR=3.60, CI=1.85-6.98, p<0.001) and cooking oil fumes (adjusted OR=3.27, CI=1.55-6.87, p=0.002), betel quid chewing (adjusted OR=3.85, CI=1.96-7.55, p<0.001), tobacco smoking (adjusted OR=4.42, CI=2.27-8.63, p<0.001) and alcohol consumption (adjusted OR=3.31, CI=1.10-10.03, p=0.034) were significant regarding the increased risk of lung cancer in the study population. Conclusions: The present study provided preliminary evidence that a p53 codon 72 polymorphism may effect lung cancer risk in the study population, interacting synergistically with environmental factors.

Role of ion-acoustic wave energy in enhanced X-mode radiation phenomena in magnetospheric plasma

Saikia Banashree,Deka P. N. 한국물리학회 2024 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.84 No.3

Most of the energy in magnetospheric plasma is available in the form of low-frequency turbulence. In this paper, we have explored the possibility of pumping such low-frequency turbulence wave energy into high-frequency X-mode in the magnetosphere. We have considered the wave energy up-conversion process through the nonlinear wave-particle interaction of the ion-acoustic wave and the X-mode wave. In this model of wave energy up-conversion, we have considered a particle distribution of modifed Maxwellian with the involvement of a gradient parameter associated with the spatial gradient and temperature gradient of magnetospheric plasma. When considering the Vlasov–Maxwell system of equations to describe the wave interaction process, we have evaluated the fuctuating parts of the particle distribution function due to the ion-acoustic wave feld for the modulated feld and the nonlinear fuctuating parts of the distribution function due to X-mode. The nonlinear dispersion relation for X-mode enables us to estimate the growth of X-mode at the expense of the ion-acoustic wave energy of the magnetospheric plasma. We have also demonstrated that how this growth process is infuenced by gradient parameters associated with this system.