Physio-Morphological Changes in a Riboflavin Producer Eremothecium ashbyii DT1 and UV Mutants in Submerged Fermentation

Venugopal, Pujari,Chandra, T. S. 한국미생물 · 생명공학회 2001 Journal of microbiology and biotechnology Vol.11 No.4

By UV-irradiation of Eremothecium ashbyii DTl, a highly flavinogenic mutant (UV-18-57) and a nonflavinogenic mutant (UV-85) were obtained. The physio-morphological characteristics of these three strains were studied on glucose medium in submerged fermentation. Glucose utilization and mycelial growth occurred in 0-2 days of fermentation. By the third day, the biomass had declined. Extracellular riboflavin excretion was distinct from the second day, reaching a maximum rate by the fourth day. The hyphae of the highly flavinogenic mutant UV-18-57 were broader than DTI, while the nonflavinogenic UV-85 hyphae were very thin. Riboflavin accumulation was high in UV-18-57 (extracellular riboflavin, 825㎍/ml, and intracellular, 490㎍/ml) and caused the mycelia to swell into bulbous forms. Riboflavin accumulation was less in DTI (108㎍/ml extracellular and 24㎍/ml intracellular) and correspondingly its hyphae were thinner than those of UV-18-57 and swollen bulbous mycelia were not prominent. UV-85 was nonflavinogenic and, accordingly, its morphological characteristics included long thin filaments with no intracellular riboflavin accumulation. A large number of greenish fluorescence spores were seen in UV-18-57, whereas DTI had less spores and UV-85 was nonsporulating. Sporulation is correlated with riboflavin production. UV- 18-57 had better mycelial integrity and lysis started only by the seventh day, whereas DTI and UV-85 started to lyze earlier by 4-5 days. By the late stage of fermentation (eighth day), DT1 had a few long, thin filaments indicating some secondary growth, whereas UV-85 showed a compact pellet form of mycelia. Most mycelia of UV-18-57 still appeared intact.

Investigation of transfer characteristics of high performance graphene flakes.

Venugopal, Gunasekaran,Krishnamoorthy, Karthikeyan,Kim, Sang-Jae American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.5

<P>In this article, we attempted a study on field effect transport characteristics of graphene flakes. These graphene flakes were exfoliated by mechanical peeling-off technique and the electrical contacts were patterned by photo-lithographic method. Graphene devices have shown better transfer characteristics which was obtained even in low-voltage (< 5 V). Back-gated graphene transistors were patterned on oxidized silicon wafers. A clear n-type to p-type transition at Dirac point and higher electron drain-current modulation in positive back-gate field with current minimum (the Dirac point) were observed at V(GS) = -1.7 V. The carrier mobility was determined from the measured transconductance. The transconductance of the graphene transistors was observed as high as 18.6 microS with a channel length of 68 microm. A maximum electron mobility of 1870 +/- 143 cm2/V x s and hole mobility of 1050 +/- 35 cm2/V x s were achieved at a drain bias 2.1 V which are comparatively higher values among reported for mechanically exfoliated graphene using lithographic method. The fabricated devices also sustained with high-current density for 40 hr in continuous operation without any change in device resistance, which could be applied for robust wiring applications.</P>

Hepatoprotective Role of Ferulic Acid: A Dose-Dependent Study

Venugopal Padmanabhan Menon,Kode Aruna,Penumathsa Suresh Varma,Rajagopalan Rukkumani 한국식품영양과학회 2004 Journal of medicinal food Vol.7 No.4

Alcohol use is contributing to an unprecedented decline in life expectancy. Damage to the liver after ethanoladministration is a well-known phenomenon. Free radical mechanisms have been proposed to play a part in ethanol-inducedliver toxicity. Ingestion of diets rich in polyunsaturated fatty acids (PUFAs) along with alcohol is known to result in enhancedliver damage. The present work is aimed at evaluating the protective role of ferulic acid, a naturally occurring plant compo-nent, on alcohol- and PUFA-induced liver toxicity. Three different doses of ferulic acid (10, 20, and 40 mg/kg of body weight)were administered to rats given alcohol, heated PUFA (.PUFA), and alcohol . . PUFA. Influence of ferulic acid on alco-hol- and PUFA-induced liver damage was evaluated by analyzing the activities of the liver marker enzymes alkaline phos-phatase, .-glutamyl transferase, alanine transaminase, and aspartate transaminase. The activities of these liver marker enzymeswere increased in the alcohol, .PUFA, and alcohol .. PUFA groups but were decreased significantly on treatment with fer-ulic acid. The low dose (10 mg/kg of body weight) was not effective, but both 20 mg and 40 mg/kg of body weight werefound to be effective. The 20 mg/kg of body weight dose was found to be more effective than 40 mg/kg of body weight (thehigh dose). The administration of ferulic acid to normal rats did not produce any harmful effects. Thus our results show thatferulic acid is an effective anti-hepatotoxic agent without side effects and may be a good candidate in the current search fora natural hepatoprotective agent.

A Sectional Matrix Method for IPT Coil Shape Optimization

Venugopal Prasanth,Pavol Bauer,J.A. Ferreira 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In this paper, Neumann’s integral is evaluated for computing self-inductance using a multi-turn sectional matrix method. Analytical equations are derived considering the increase in dimensions of the coil due to an impinging air-gap between the turns. The resulting sectional self-inductance matrix is computed and the concepts of sectional partial self-inductance and sectional partial mutual inductance are introduced. The effects of the various partial inductances are considered as a function of the air-gap, dimensions and turns. Further, the mutual inductance of a pair of coils is considered and the coupling is obtained analytically. The coils considered are to be used for shape optimization of IPT coils. Finally, the results are compared with experimentation. This technique being generic can be applied to a number of different polygonal shapes and can be further simplified by the theory of vector decomposition of current elements. A case study with self-inductance and perimeter as optimization objective is considered.

Mechanically Relevant Anatomy of the Axis Vertebra and Its Relation to Hangman’s Fracture: An Illustrated Essay

Venugopal K. Menon 대한척추신경외과학회 2019 Neurospine Vol.16 No.2

patterns within the bone, and on that basis, to postulate its mechanism of injury, a literature review was conducted of the anatomy and biomechanics of Axis fractures. Two hypotheses have been presented: the internal gear hypothesis and the leaf spring hypothesis. Both are based on the trabecular anatomy of the vertebra and its load transmission patterns. The relationship of the Axis with Hangman’s injury is also discussed. According to the leaf spring hypothesis, the C2 pedicle corresponds to the shackle in the assembly and constitutes the weak link. The trabecular architecture of the Axis is such that the primary compression of the trabeculae is directed from the superior facet to the C2–3 endplate, with few trabeculae directed to the inferior facet. Along with the trabecular void in this area, this renders the isthmus vulnerable to trauma. The isthmus of the Axis is biomechanically susceptible to injury due to its unique anatomy in relation to the whole cervical spine and the internal load transmission patterns of the bone. The author suggests that in the flexion type of Hangman’s injury, the C1–2 posterior ligaments are disrupted and need to be addressed.

An Enhanced Neural Network Approach for Numeral Recognition

Venugopal, Anita,Ali, Ashraf International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.3

Object classification is one of the main fields in neural networks and has attracted the interest of many researchers. Although there have been vast advancements in this area, still there are many challenges that are faced even in the current era due to its inefficiency in handling large data, linguistic and dimensional complexities. Powerful hardware and software approaches in Neural Networks such as Deep Neural Networks present efficient mechanisms and contribute a lot to the field of object recognition as well as to handle time series classification. Due to the high rate of accuracy in terms of prediction rate, a neural network is often preferred in applications that require identification, segmentation, and detection based on features. Neural networks self-learning ability has revolutionized computing power and has its application in numerous fields such as powering unmanned self-driving vehicles, speech recognition, etc. In this paper, the experiment is conducted to implement a neural approach to identify numbers in different formats without human intervention. Measures are taken to improve the efficiency of the machines to classify and identify numbers. Experimental results show the importance of having training sets to achieve better recognition accuracy.

Comparative Effects of Curcumin and Its Analog on Alcohol- and Polyunsaturated Fatty Acid-Induced Alterations in Circulatory Lipid Profiles

Venugopal P. Menon,Kode Aruna,Penumathsa Suresh Varma,Kallikat Narayanan Rajasekaran,Rajagopalan Rukkumani 한국식품영양과학회 2005 Journal of medicinal food Vol.8 No.2

Excessive alcohol intake induces hyperlipidemia. Studies suggest that natural principles and their analogs are known to possess anti-hyperlipidemic properties. In the present work we tested the effect of curcumin, an active principle of turmeric (Curcuma longa), and a curcumin analog on alcohol- and thermally oxidized polyunsaturated fatty acid (PUFA)- induced hyperlipidemia. Male albino Wistar rats were used for the experimental study. Anti-hyperlipidemic activity of curcumin and curcumin analog was evaluated by analyzing the levels of cholesterol, triglycerides (TGs), phospholipids (PLs), and free fatty acids (FFAs). The results showed that the levels of cholesterol, TGs, PLs, and FFAs were increased significantly in alcohol-, PUFA-, and alcohol PUFA-treated groups, which were brought down significantly on treatment with either of the curcuminoids. Curcumin analog treatment was found to be more effective than curcumin treatment. From the results obtained, we conclude that both curcumin and its analog effectively protect the system against alcohol- and PUFA-induced hyperlipidemia and are possible candidates for the treatment of hyperlipidemia.

Effect of Photo-Irradiated Curcumin Treatment Against Oxidative Stress in Streptozotocin-Induced Diabetic Rats

Venugopal P. Menon,M. Sri Balasubashini,T. Mahesh 한국식품영양과학회 2005 Journal of medicinal food Vol.8 No.2

Increasing evidence in both experimental and clinical studies suggests that oxidative stress plays a major rolein the pathogenesis of diabetes mellitus. Although phenolic compounds attenuate oxidative stress-related damage, there areconcerns over toxicity of synthetic phenolic antioxidants, and this has considerably stimulated interest in investigating the roleof natural phenolics in medicinal application. In the present study, we examined the effect of photo-irradiated curcumin inexperimental diabetes to evaluate the anti-hyperglycemic properties of this compound on streptozotocin (40 mg/kg of bodyweight)-induced diabetes. Photo-irradiated curcumin was given at a dose of 10 or 30 mg/kg of body weight. The level ofblood glucose was elevated in diabetic animals. Circulatory lipid peroxidation, vitamin C, vitamin E, and enzymic antioxi-dants such as superoxide dismutase and catalase were analyzed. The antioxidant status decreased in diabetic animals. Oral ad-ministration of photo-irradiated curcumin for 45 days resulted in a significant decrease in the levels of blood glucose alongwith near-normalization of the enzymic activities and the levels of lipid peroxidative markers. The most effective results wereobtained on treatment with 30 mg/kg of body weight of photo-irradiated curcumin.

Peripheral Blood As a Source of Stem Cells for Regenerative Medicine: Emphasis Towards Corneal Epithelial Reconstruction—An In Vitro Study

Venugopal Balu,Mohan Sumitha,Kumary T. V.,Anil Kumar P. R. 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.4

Background: Mesenchymal stem cell-based treatments are now emerging as a therapy for corneal epithelial damage. Although bone marrow, adipose tissue and umbilical cord blood are the main sources of mesenchymal stem cells (MSCs), other tissues like the peripheral blood also harbor mesenchymal-like stem cells called peripheral blood-derived mononuclear cells (PBMNCs). These blood derived stem cells gained a lot of attention due to its minimally invasive collection and ease of isolation. In this study, the feasibility of using PBMNCs as an alternative cell source to corneal limbal stem cells envisaging corneal epithelial regeneration was evaluated. Methods: Rabbit PBMNCs were isolated using density gradient centrifugation and was evaluated for mesenchymal cell properties including stemness. PBMNCs were differentiated to corneal epithelial lineage using rabbit limbal explant conditioned media and was evaluated by immuno-cytochemistry and gene expression analysis. Further, the differentiated PBMNCs were engineered into a cell sheet using an in-house developed thermo-responsive polymer. Results: These blood derived cells were demonstrated to have similar properties to mesenchymal stem cells. Corneal epithelial lineage commitment of PBMNCs was confirmed by the positive expression of CK3/12 marker thereby demonstrating the aptness as an alternative to limbal stem cells. These differentiated cells effectively generated an in vitro cell sheet that was then demonstrated for cell sheet transfer on an ex vivo excised rabbit eye. Conclusion: PBMNCs as an alternative autologous cell source for limbal stem cells is envisaged as an effective therapeutic strategy for corneal surface reconstruction especially for patients with bilateral limbal stem cell deficiency.

Modulatory Effects of Curcumin and Curcumin Analog on Circulatory Lipid Profiles During Nicotine-Induced Toxicity in Wistar Rats

Venugopal P. Menon,K.N. Rajasekharan,C. Kalpana 한국식품영양과학회 2005 Journal of medicinal food Vol.8 No.2

Nicotine, a major toxic component of cigarette smoke, plays a key role in the development of cardiovascular disease and lung cancer. In the present study, we have synthesized an analog of curcumin and biomonitored its influence over biochemical marker enzymes and lipid profiles on nicotine-induced toxicity in Wistar rats. The effects were compared with that of curcumin, a well-known antioxidant and anti-hyperlipidemic agent. Toxicity was induced by subcutaneous injection of nicotine at a dose of 2.5 mg/kg of body weight (5 days a week, for 22 weeks), and curcumin (80 mg/kg) was given simultaneously along with nicotine by intragastric intubation for 22 weeks. Measurements of activities of the biochemical marker enzymes aspartate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase and of plasma lipid profiles were used to monitor the anti-hyperlipidemic effects of curcuminoids. In nicotine-treated rats, enhanced plasma marker enzymes and lipid profiles were observed. Administration of curcumin or curcumin analog to nicotine-treated rats significantly reduced the activity of marker enzymes and plasma lipid levels. Thus, our findings suggest that curcumin and its analog exert an anti-hyperlipidemic effect against nicotine-induced lung toxicity and may be a promising agent for treatment of hyperlipidemia and atherosclerosis