Cryopreservation and Microencapsulation of a Probiotic in Alginatechitosan Capsules Improves Survival in Simulated Gastrointestinal Conditions

Paulraj Kanmani,R. Satish Kumar,N. Yuvaraj,K. A. Paari,V. Pattukumar,Venkatesan Arul 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.6

The aim of the present study was to focus on the impact of two different methods and the effects of cryoprotectants on the survival of a probiotic bacterium,Streptococcus phocae PI80, during storage. For the protection of freeze dried cells, the optimal storage conditions were determined with a high survival rate. After the freeze drying process, all cryoprotectants exhibited a protective effect on cell viability at all storage temperatures. High relative cell viability was observed when cells were incubated at −20°C, which was optimum for the protection of S. phocae PI80. Trehalose was the most promising cryoprotectant at all temperatures during the storage period of bacterial cells. The combination of trehalose + skim milk showed more than 85% survivability compared to other combinations at −20°C for 60 days. In addition,encapsulation of probiotic cells into alginate-chitosan gel capsules showed better survival of S. phocae cells (5.468 ±0.15 LogCFU/mL) with high bacteriocin activity at −20°C for six months. The cell-loaded microcapsules remained stable when treated with simulated gastric and intestinal fluids. After 6 h in vivo treatment, the capsules were found to be broken, releasing the probiotic cells directly into the intestinal system of rats. Therefore, microencapsulation was found to be the most efficient technique, which not only protected the cells for a longer time but also released the cells into the in vivo intestinal system.

Codebook-Based Lattice-Reduction-Aided Precoding for Limited-Feedback Coded MIMO Systems

Hyun Jong Yang,Joohwan Chun,Youngchol Choi,Sungsoo Kim,Paulraj, A. Institute of Electrical and Electronics Engineers 2012 IEEE Transactions on Communications Vol. No.

<P>Lattice-reduction-aided precoding (LRP) provides near-capacity rates with the use of low-complexity linear receivers for coded multiple-input multiple-output (MIMO) systems. However, a large amount of feedback in the feedback for an integer or binary precoding matrix has been a bottleneck in its implementation. In this paper, we propose a codebook-based LRP scheme for limited-feedback coded MIMO systems. The proposed LRP scheme follows the fundamentals of the previous LRP scheme that employed multilevel binary coset coding so that the precoding matrix is binary. In the proposed LRP scheme, the conventional precoding matrix obtained from the Lenstra-Lenstra-Lovasz algorithm is modified to specific forms that are predefined in a codebook set. The new precoding matrix is selected such that the lower bound on the capacity is maximized for a given codebook set, while the codebook set is designed offline such that the upper bound of the average capacity loss induced by the limitation on the codebook size is minimized. The simulation results show that the proposed LRP scheme nearly achieves the achievable rate of the conventional LRP scheme with a greatly reduced amount of feedback.</P>

Asymptotic Capacity of the Separated MIMO Two-Way Relay Channel

Hyun Jong Yang,Joohwan Chun,Paulraj, A. IEEE 2011 IEEE transactions on information theory Vol.57 No.11

<P>A multiple-input multiple-output two-way relay channel consisting of two communication nodes and a full-duplex relay node in which no direct link exists between the two communication nodes is considered. We propose an achievable scheme that employs horizontally encoded lattice codes combined with generalized singular value decomposition-based precoding for the first phase. The second phase of the proposed scheme follows the fundamentals of the previous scheme, which uses vertically encoded structural bining, with the only difference that the added codeword of the two codewords from the communication nodes, instead of those two individual codewords, is decoded and retransmitted in the proposed scheme. We show that the proposed scheme achieves the cut-set bound asymptotically as the signal-to-noise ratios of the channels tend to infinity.</P>

Overview of Space-Time Processing of the Next Generation

A. Paulraj 대한전자공학회 1998 대한전자공학회 심포지엄 논문집 Vol.3 No.-

Experimental investigation of vibration intensities of CNC machining centre by microphone signals with the effect of TiN/epoxy coated tool holder

A. Bovas Herbert Bejaxhin,G. Paulraj 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.3

Vibration monitoring and analysis is the valuable implement in the field of predictive preservation and it is an important consideration in engineering. The effect of vibration on machine structures are the origin of variances in its precision. Especially Titanium and Aluminium based coatings with the contribution of Ni and Cr particles proved that best wear and corrosion resistance, high hardness, chemical, thermal constancy and also improved pulsation control. The performance of the machining has to be evaluated based on the effect of coatings on the accessories of cutting profiles. Here the experimentation is carried out for various speed, feed and depth of cut by TiN, TiAlN and AlCrN coated end milling cutters and titanium nitrate (TiN), fusion bonded epoxy (FBE) coated BT40 tool holder in CNC milling machine. This paper presents and explores a fresh established copper coiled vibration monitoring microphone system connected with the cross-platform tool Audacity 2.1.0 for recording the vibration as sound signals. It is compared simultaneously with the corresponding displacement values by vibration tester. Here, the design of experiment (DOE) with full factorial design has been discovered to deliver 27 slots on EN 32 Mild steel plate by milling operation with the help of Taguchi and ANOVA approach. It is found that the effect of coatings on tool and the holder is the most major dominating thing on vibration signals of the machine structure. Experimentally it showed good agreement that the minimization of vibration by using FBE coated tool holder and AlCrN coated end milling tool is good which is acknowledged through the peak values of dB noise signals received from the vibration monitoring microphone system. Variation in amplitudes and displacements are clearly identified the minimized vibration levels for varying cutting conditions.

b-Sitosterol Prevents Lipid Peroxidation and Improves Antioxidant Status and Histoarchitecture in Rats with 1,2-Dimethylhydrazine-Induced Colon Cancer

Arul Albert Baskar,Khalid S. Al Numair,Micheal Gabriel Paulraj,Mohammed A. Alsaif,May Al Muamar,Savarimuthu Ignacimuthu 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.4

Oxidative stress has become widely viewed as an underlying condition in diseases such as ischemia/reperfusion disorders, central nervous system disorders, cardiovascular disease, cancer, diabetes, etc. The role that antioxidants play in the process of carcinogenesis has recently gained considerable attention. b-Sitosterol, a naturally occurring sterol molecule, is a relatively mild to moderate antioxidant and exerts beneficial effects in vitro by decreasing the level of reactive oxygen species. The present study evaluated the antioxidant potential of b-sitosterol in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. The enzymatic and nonenzymatic antioxidants and lipid peroxides in colonic and hepatic tissues were evaluated. Generation of reactive oxygen species, beyond the body’s endogenous antioxidant capacity, causes a severe imbalance of cellular antioxidant defense mechanisms. Elevated levels of liver lipid peroxides by DMH induction were effectively decreased by b-sitosterol supplementation. b-Sitosterol also exhibited a protective action against DMH-induced depletion of antioxidants such as catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione Stransferase,and reduced glutathione in colonic and hepatic tissues of experimental animals. Supplementation with b-sitosterol restored the levels of nonenzymatic antioxidants (vitamin C, vitamin E, and glutathione). Histopathological alterations in DMH-induced animals were restored to near normal in rats treated with b-sitosterol. Thus, b-sitosterol by virtue of its antioxidant potential may be used as an effective agent to reduce DMH-induced oxidative stress in Wistar rats and may be an effective chemopreventive drug for colon carcinogenesis.

MIMO Systems Based on Modulation Diversity

Heunchul Lee,Paulraj, A IEEE 2010 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.58 No.12

<P>This letter proposes a new approach to achieve the maximum diversity gain in the vertical Bell Laboratories Layered Space-Time (V-BLAST) system over multiple-input multiple-output (MIMO) Rayleigh channels. First, we will briefly review the modulation diversity scheme based on real-valued multidimensional rotated constellations that has been proposed to obtain high diversity orders for single-input single-output (SISO) systems. Then, this letter extends the modulation diversity scheme to V-BLAST MIMO systems in order to achieve the maximum diversity gain without additional power or bandwidth consumption. The proposed method is particularly suitable for MIMO applications which employ channel codes with high rate in order to support high spectral efficiency.</P>