Evaluation of the effects of oral rinses on the retention and surface topography of the ball attachment complex for implant overdentures

Dhanapriya Gopalakrishnan(Dhanapriya Gopalakrishnan ),Azhagarasan Nagarasampatti Sivaprakasam(Azhagarasan Nagarasampatti Sivaprakasam ),Vidhya Jeyapalan(Vidhya Jeyapalan ),Jayakrishnakumar Sampathkuma 대한치과이식임플란트학회 2023 The Korean Academy of Implant Dentistry Vol.42 No.1

Purpose: To evaluate the effect of two different oral rinses on the retention and surface topography of ball attachments for implant overdentures. Materials and Methods: Thirty metal housing and the nylon cap inserts (Adin, Israel) were placed on the master block and the attachment assemblies were transferred to prosthetic blocks using the direct pickup technique. Group I had ten test samples immersed in water, Group II had ten test samples immersed in Listerine® Cool Mint®(J&J, India), Group III had ten test samples immersed in Colgate Vedshakthi oil-based herbal oral rinse (Colgate-Palmolive, India). The retention force was tested at baseline and after immersion in the respective oral rinses at 360 cycles (simulating 3 months) and 720 cycles (simulating 6 months) of clinical use, using a universal testing machine (Shimadzu, AG-X plus 50KN, Europe, GmBH) at a crosshead speed of 50 mm/min. The data was analyzed using the repeated measures ANOVA test, one-way ANOVA test, and post hoc analysis (SPSS23, Munich, Germany). The surface topography was assessed initially and subsequently after immersion in the oral rinses after 360 and 720 insertion-removal cycles using a stereomicroscope (Leica M205C, Germany). Results: At 360 cycles, the mean retention force (MRF) exhibited by Group I was higher than that of Group III and this difference was significant. The MRF of Group II was also significantly higher than Group III. At 720 cycles, the MRF exhibited by Group I was higher than that of Group II and the difference was significant. Also, the MRF of Group I was significantly higher than that of Group III, and the MRF of Group II was significantly higher than that of the Group III test samples. In Group I, the percentage loss in the MRF at the end of 360 and 720 cycles was 4.96% and 6.37%, respectively. In Group II, it was 6.82% and 9.41%, respectively, and in Group III it was 14.75% and. 16.60%, respectively. Conclusions: Colgate Vedshakti caused the highest surface topographic changes. This corroborates with the lower retention obtained, followed by Listerine® Cool Mint®, and the least changes were observed for samples immersed in water, which corroborates with the greater retention obtained in the study.

Effect of Marsilea quadrifolia (L.) on carbohydrate metabolic enzymes in alloxan induced diabetic rats

Gopalakrishnan Karikalan,Udayakumar Rajangam 한국약제학회 2018 Journal of Pharmaceutical Investigation Vol.48 No.4

Marsilea quadrifolia is an indigenous medicinal plant and it has a folk reputation in central and southern India as hypoglycemic agent. The present study was aimed to evaluate the effect of methanolic leaf and stem extracts of Marsilea quadrifolia on carbohydrate metabolic enzymes in alloxan induced diabetic rats. In this study, the blood glucose level was increased in alloxan induced diabetic rats when compared to normal control rats. The decreased level of blood glucose was observed in diabetic rats treated with leaf and stem of M. quadrifolia. The activities of hexokinase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphatase, fructose 1,6-bisphosphatase and glucose-6-phosphate dehydrogenase in liver and kidney and glycogen content, glycogen synthase and glycogen phosphorylase in liver were analysed. Glibenclamide was used as a reference drug in the present investigation. The activities of hexokinase, pyruvate kinase and glucose- 6-phosphate dehydrogenase were significantly decreased and the activities of lactate dehydrogenase, glucose-6-phosphatase and fructose 1,6-bisphosphatase were significantly increased in liver and kidney of alloxan induced diabetic rats when compared to normal control rats. Oral administration of methanolic leaf and stem extracts of M. quadrifolia (300 mg/kg bw) to diabetic rats for 45 days showed significantly reverted levels of above mentioned enzymes. The levels of glycogen and glycogen synthase in liver were significantly decreased and the glycogen phosphorylase activity was significantly increased in diabetic rats when compared to normal control rats. The diabetic rats treated with leaf and stem extracts of M. quadrifolia reverted the levels of glycogen, glycogen synthase and glycogen phosphorylase to near normal. The present study clearly indicates that the methanolic leaf and stem extracts of M. quadrifolia possesses potent antidiabetic activity.

5,7-Diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino [3,4-d]-1,2,3-selenadiazoles의 손쉬운 One-pot 합성

Gopalakrishnan, M.,Thanusu, J.,Kanagarajan, V. 대한화학회 2008 대한화학회지 Vol.52 No.1

조사 아래 불균일촉매 NaHSO4.SiO2의 존재하에서 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino [3,4-d]-1,2,3-selenadiazoles의 one-pot. A simple synthetic strategy is described for one-pot synthesis of 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino[3,4-d]-1,2,3-selenadiazoles (11-15) in the presence of NaHSO4.SiO2 as a heterogeneous catalyst in dry media under microwave irradiation.Key words: One-pot synthesis, 3,3-Dimethyl-2,6-diarylpiperidin-4-one; 1,2,3-Selenadiazoles; Selenium dioxide; NaHSO4.SiO2 Heterogeneous catalyst.

Dry Media Reaction Procedure for Synthesis of α,β-Unsaturated Acids, α-Cyanoacrylonitriles and α-Cyanoacrylates via Knoevenagel Condensation Using NaHSO₄·SiO₂ Catalyst

Gopalakrishnan, M.,Sureshkumar, P.,Kanagarajan, V.,Thanusu, J.,Thirunavukkarasu, S. Korean Chemical Society 2007 대한화학회지 Vol.51 No.4

NaHSO4·SiO2를 사용하는 solvent-free 조건하에서 E-geometry를 가진 α,β의 불포화산, α-Cyanoacrylonitriles 와 α-Cyanoacrylates의 효율적인 입체선택적 반응을 수행하였다. Efficient stereoselective synthesis of α,β-Unsaturated acids, α-Cyanoacrylonitriles and α-Cyanoacrylates has been carried out in the presence of NaHSO4·SiO2 under solvent?free conditions with an E-geometry.

Anaerobic Digestion of Food Waste: Meshophilic vs Thermophilic Regime

( Gopalakrishnan Kumar ),( Hyun Jun Ju ),( Sang-hyuon Kim ) 한국폐기물자원순환학회(구 한국폐기물학회) 2014 한국폐기물자원순환학회 심포지움 Vol.2014 No.1

Food waste generation around the globe is a serious issue that needs to be concerned. Developing suitable treatment methods along with the generation of energy (methane) is a common practice to make the world sustainable. In this study, methane generation of food waste has been reported in mesophilic and thermophilic regimes at various hydraulic retention times (HRT) and organic loading rates (OLR). Different reactor configurations were used for mesophilic and thermophilic operations. The influent concentrations were ranged from 30 to 110 g COD/L corresponding to the OLR of 1.0 to 5.5 Kg COD/m³*d, respectively. Three different HRTs evaluated were 30, 24 and 20 days in both regimes. The production performances showed that an increase in biogas and methane production while increasing the substrate concentration in both temperatures. However, better results were obtained from thermophilic temperature due to the hydrolysis of the complex polymers at higher temperatures. Peak methane productivities attained at mesophilic and thermophilic regimes were 1.30 and 0.95 m³/m³*d, respectively. However, the maximal yield achieved were at 50 g CODL and at HRT of 24 d in both the cases and the values were 264 and 221 m3/ton COD, respectively. The COD removal rate was ranged from 54-86% in case of thermophilic and 61-87% in case of mesophilic, respectively. The results of this study could aid in the development of sustainable methane production technologies using food waste as carbon source.

Modified Chilled Coil Model Development and Application to Turbine Inlet Air Cooling

Gopalakrishnan Anand,Ellen Makar 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.1

A Turbine Inlet Air Conditioning (TIAC) system can chill the inlet air of the turbine to maintain maximum turbine performance at all ambient temperatures. However, turbine characteristics, performance guarantees and bell-mouth icing considerations require accurate prediction of the chilling coil performance over a wide range of operating conditions. A modified wet-surface model (MWSM) is developed to more accurately predict the chilling coil performance. The higher accuracy of the model is demonstrated by applying the model to simulate performance data of two different coils. The data covered a wide range of operating conditions with ambient temperature vary from 43.3∘C to 9.7 ∘ C dry bulb and 27.2 ∘C to 6.1 ∘C wet bulb. The turbine flow rate varies from 100% to 43% with chilled air temperature in the range of 3.3–14 ∘ C and chilling load variation of 100% to 5%. The chilled water flow rate varies from 100% to 32% with supply glycol-water temperature in the range of −2.2–6.1 ∘ C. The MWSM uses 11 empirical parameters evaluated from the coil performance data and is able to correlate the data with an adjusted coefficient of determination (R 2 adjRadj2) of over 99%. The higher accuracy of the modified model enables the development of a more robust controls strategy required to maintain the inlet air temperature at the set point with varying ambient temperatures and chilling load conditions. The model can also be applied to other chilling and dehumidification applications especially those experiencing wide variations in operating conditions and load or those requiring close control of the chilling and dehumidification process.

Cell Cycle and Mismatch Repair Genes as Potential Biomarkers in Arabidopsis thaliana Seedlings Exposed to Silver Nanoparticles

Gopalakrishnan Nair, Prakash M.,Chung, Ill-Min Springer-Verlag 2014 Bulletin of environmental contamination and toxico Vol.92 No.6

Copper oxide nanoparticle toxicity in mung bean (Vigna radiata L.) seedlings: physiological and molecular level responses of in vitro grown plants

Gopalakrishnan Nair, P. M.,Kim, S. H.,Chung, I. M. POLISH ACADEMY SCIENCES WARSAW 2014 ACTA PHYSIOLOGIAE PLANTARUM Vol.36 No.11

Subfreezing Absorption Refrigeration for Industrial CHP

Gopalakrishnan Anand,Donald C Erickson,Ellen Makar 대한설비공학회 2018 International Journal Of Air-Conditioning and Refr Vol.26 No.4

The design and operation of an advanced absorption refrigeration unit (Thermochiller) as part of an industrial combined heat and power (CHP) system is presented. The unit is installed at a vegetable processing plant in Santa Maria, California. The overall integrated system includes the engine package with waste heat recovery, Thermochiller, cooling tower, and chilling load interface. The unique feature of the system is that both the exhaust and jacket heat are used to supply subfreezing refrigeration. To achieve the low refrigeration temperatures of interest to industrial applications, all components of this integrated system needed careful consideration and optimization. The CHP system has a low emission natural gas-fired 633kW reciprocating engine cogeneration package. Both the exhaust heat and jacket heat are recovered and delivered via a hot glycol loop with 105 ∘ C supply temperature and 80 ∘C return. The 125 ton ammonia absorption chiller (TC125) chills propylene glycol to −6 ∘ C and has a coefficient of performance of 0.63. TC125 has peak electric demand of 10 kW for pumps and 8 kW for the cooling tower fan. The CHP system, including TC125, operates 20 h per day, six days per week. All operations of TC125 are completely automatic and autonomous, including startups and shutdowns. Industrial refrigeration is typically a 24/7 load and highly energy-intensive. By converting all the engine waste heat to subfreezing refrigeration, Thermochiller brings added value to cogeneration or CHP projects.

Modulation of Activator Protein-1 (AP-1) and MAPK Pathway by Flavonoids in Human Prostate Cancer PC3 Cells

Gopalakrishnan, Avanthika,Xu, Chang-Jiang,Nair, Sujit S.,Chen, Chi,Hebbar, Vidya,Kong, Ah-Ng Tony The Pharmaceutical Society of Korea 2006 Archives of Pharmacal Research Vol.29 No.8

In last couple of decades the use of natural compounds like flavonoids as chemopreventive agents has gained much attention. Our current study focuses on identifying chemopreventive flavonoids and their mechanism of action on human prostate cancer cells. Human prostate cancer cells (PC3), stably transfected with activator protein 1 (AP-1) luciferase reporter gene were treated with four main classes of flavonoids namely flavonols, flavones, flavonones, and isoflavones. The maximum AP-1 luciferase induction of about 3 fold over control was observed with $20\;{\mu}M$ concentrations of quercetin, chrysin and genistein and $50\;{\mu}M$ concentration of kaempferol. At higher concentrations, most of the flavonoids demonstrated inhibition of AP-1 activity. The MTS assay for cell viability at 24 h showed that even at a very high concentration $(500\;{\mu}M)$, cell death was minimal for most of the flavonoids. To determine the role of MAPK pathway in the induction of AP-1 by flavonoids, Western blot of phospho MAPK proteins was performed. Four out of the eight flavonoids namely kaempferol, apigenin, genistein and naringenin were used for the Western Blot analysis. Induction of phospho-JNK and phospho-ERK activity was observed after two hour incubation of PC3-AP1 cells with flavonoids. However no induction of phospho-p38 activity was observed. Furthermore, pretreating the cells with specific inhibitors of JNK reduced the AP-1 luciferase activity that was induced by genistein while pretreatment with MEK inhibitor reduced the AP-1 luciferase activity induced by kaempferol. The pharmacological inhibitors did not affect the AP-1 luciferase activity induced by apigenin and naringenin. These results suggest the possible involvement of JNK pathway in genistein induced AP-1 activity while the ERK pathway seems to play an important role in kaempferol induced AP-1 activity.