Magnetic field-inducible drug-eluting nanoparticles for image-guided thermo-chemotherapy

Thirunavukkarasu, Guru Karthikeyan,Cherukula, Kondareddy,Lee, Hwangjae,Jeong, Yong Yeon,Park, In-Kyu,Lee, Jae Young Elsevier 2018 Biomaterials Vol.180 No.-

<P><B>Abstract</B></P> <P>Multifunctional nanoparticles integrating cancer cell imaging and treatment modalities into a single platform are recognized as a promising approach; however, their development currently remains a challenge. In this study, we synthesized magnetic field-inducible drug-eluting nanoparticles (MIDENs) by embedding superparamagnetic iron oxide nanoparticles (Fe<SUB>3</SUB>O<SUB>4</SUB>; SPIONs) and cancer therapeutic drugs (doxorubicin; DOX) in a temperature-responsive poly (lactic-co-glycolic acid) (PLGA) nanomatrix. Application of an external alternating magnetic field (AMF) generated heat above 42 °C and subsequent transition of the PLGA polymer matrix (T<SUB>g</SUB> = 42–45 °C) from the glassy to the rubbery state, facilitating the controlled release of the loaded DOX, ultimately allowing for simultaneous hyperthermia and local heat-triggered chemotherapy for efficient dual cancer treatment. The average size of the synthesized MIDENs was 172.1 ± 3.20 nm in diameter. <I>In vitro</I> studies showed that the MIDENs were cytocompatible and especially effective in destroying CT26 colon cancer cells with AMF application. <I>In vivo</I> studies revealed that the MIDENs enabled enhanced T<SUB>2</SUB> contrast magnetic resonance imaging and a significant suppression of malignant tumor growth under an AMF. Our multifunctional MIDENs, composed of biocompatible substances and therapeutic/imaging modalities, will be greatly beneficial for cancer image-guided thermo-chemotherapy applications.</P>

Time-Course Analysis of the Neuroanatomical Correlates of Sexual Arousal Evoked by Erotic Video Stimuli in Healthy Males

Thirunavukkarasu Sundaram,정광우,김태훈,김광원,백한수,강형근 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.3

Objective: To assess the dynamic activations of the key brain areas associated with the time-course of the sexual arousal evoked by visual sexual stimuli in healthy male subjects. Materials and Methods: Fourteen right-handed heterosexual male volunteers participated in this study. Alternatively combined rest period and erotic video visual stimulation were used according to the standard block design. In order to illustrate and quantify the spatiotemporal activation patterns of the key brain regions, the activation period was divided into three different stages as the EARLY, MID and LATE stages. Results: For the group result (p < 0.05), when comparing the MID stage with the EARLY stage, a significant increase of the brain activation was observed in the areas that included the inferior frontal gyrus, the supplementary motor area, the hippocampus, the head of the caudate nucleus, the midbrain, the superior occipital gyrus and the fusiform gyrus. At the same time, when comparing the EARLY stage with the MID stage, the putamen, the globus pallidus, the pons, the thalamus, the hypothalamus, the lingual gyrus and the cuneus yielded significantly increased activations. When comparing the LATE stage with the MID stage, all the above mentioned brain regions showed elevated activations except the hippocampus. Conclusion: Our results illustrate the spatiotemporal activation patterns of the key brain regions across the three stages of visual sexual arousal. Objective: To assess the dynamic activations of the key brain areas associated with the time-course of the sexual arousal evoked by visual sexual stimuli in healthy male subjects. Materials and Methods: Fourteen right-handed heterosexual male volunteers participated in this study. Alternatively combined rest period and erotic video visual stimulation were used according to the standard block design. In order to illustrate and quantify the spatiotemporal activation patterns of the key brain regions, the activation period was divided into three different stages as the EARLY, MID and LATE stages. Results: For the group result (p < 0.05), when comparing the MID stage with the EARLY stage, a significant increase of the brain activation was observed in the areas that included the inferior frontal gyrus, the supplementary motor area, the hippocampus, the head of the caudate nucleus, the midbrain, the superior occipital gyrus and the fusiform gyrus. At the same time, when comparing the EARLY stage with the MID stage, the putamen, the globus pallidus, the pons, the thalamus, the hypothalamus, the lingual gyrus and the cuneus yielded significantly increased activations. When comparing the LATE stage with the MID stage, all the above mentioned brain regions showed elevated activations except the hippocampus. Conclusion: Our results illustrate the spatiotemporal activation patterns of the key brain regions across the three stages of visual sexual arousal.

Throughput maximization for underlay CR multicarrier NOMA network with cooperative communication

Manimekalai, Thirunavukkarasu,Joan, Sparjan Romera,Laxmikandan, Thangavelu Electronics and Telecommunications Research Instit 2020 ETRI Journal Vol.42 No.6

The non-orthogonal multiple access (NOMA) technique offers throughput improvement to meet the demands of the future generation of wireless communication networks. The objective of this work is to further improve the throughput by including an underlay cognitive radio network with an existing multi-carrier NOMA network, using cooperative communication. The throughput is maximized by optimal resource allocation, namely, power allocation, subcarrier assignment, relay selection, user pairing, and subcarrier pairing. Optimal power allocation to the primary and secondary users is accomplished in a way that target rate constraints of the primary users are not affected. The throughput maximization is a combinatorial optimization problem, and the computational complexity increases as the number of users and/or subcarriers in the network increases. To this end, to reduce the computational complexity, a dynamic network resource allocation algorithm is proposed for combinatorial optimization. The simulation results show that the proposed network improves the throughput.

Time-Course Analysis of the Neuroanatomical Correlates of Sexual Arousal Evoked by Erotic Video Stimuli in Healthy Males

Sundaram, Thirunavukkarasu,Jeong, Gwang-Woo,Kim, Tae-Hoon,Kim, Gwang-Won,Baek, Han-Su,Kang, Heoung-Keun The Korean Society of Radiology 2010 KOREAN JOURNAL OF RADIOLOGY Vol.11 No.3

<P><B>Objective</B></P><P>To assess the dynamic activations of the key brain areas associated with the time-course of the sexual arousal evoked by visual sexual stimuli in healthy male subjects.</P><P><B>Materials and Methods</B></P><P>Fourteen right-handed heterosexual male volunteers participated in this study. Alternatively combined rest period and erotic video visual stimulation were used according to the standard block design. In order to illustrate and quantify the spatiotemporal activation patterns of the key brain regions, the activation period was divided into three different stages as the EARLY, MID and LATE stages.</P><P><B>Results</B></P><P>For the group result (<I>p</I> < 0.05), when comparing the MID stage with the EARLY stage, a significant increase of the brain activation was observed in the areas that included the inferior frontal gyrus, the supplementary motor area, the hippocampus, the head of the caudate nucleus, the midbrain, the superior occipital gyrus and the fusiform gyrus. At the same time, when comparing the EARLY stage with the MID stage, the putamen, the globus pallidus, the pons, the thalamus, the hypothalamus, the lingual gyrus and the cuneus yielded significantly increased activations. When comparing the LATE stage with the MID stage, all the above mentioned brain regions showed elevated activations except the hippocampus.</P><P><B>Conclusion</B></P><P>Our results illustrate the spatiotemporal activation patterns of the key brain regions across the three stages of visual sexual arousal.</P>

On-demand generation of heat and free radicals for dual cancer therapy using thermal initiator- and gold nanorod-embedded PLGA nanocomplexes

Guru Karthikeyan Thirunavukkarasu,G.R. Nirmal,이황재,이민규,박인규,이재영 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.69 No.-

Dual cancer therapy is an attractive strategy that can generate synergistic effects and also reduce drug-related side effects. Here, we developed multifunctional nanocomplexes capable of remote on-demand production of hyperthermia and free radicals in response to near infrared (NIR) light irradiation To this end, thermal initiator and gold nanorods were embedded in nano-sized temperature-responsive poly(lactic acid-co-glycolic acid). In vitro studies demonstrated controllable heat and radical production from the nanocomplexes with NIR and effective eradication of CT26 colon cancer cells with our nanocomplexes. Hence, our smart nanomaterial will potentially contribute precise and effective dual cancer treatment.

Remote induction of in situ hydrogelation in a deep tissue, using an alternating magnetic field and superparamagnetic nanoparticles

Lee, Hwangjae,Thirunavukkarasu, Guru Karthikeyan,Kim, Semin,Lee, Jae Young Springer-Verlag 2018 Nano research Vol.11 No.11

Micropatterning of Lipid Bilayers in a Microfluidic System via Forced Vesicle Fusion

김유정,Sankar Thirunavukkarasu,박주영,정형일 한국바이오칩학회 2007 BioChip Journal Vol.1 No.3

Substrate-supported planar lipid bilayers (SPB) are excellent model for bio-membranes, and have potential scientific and technological applications. Due to these features, SPBs have been studied to determine if their application can be useful for biological analyses, such as the evaluation of cell to cell interactions or as cell based biosensors. In this study, the patterning of 1, 2-bis(10, 12-tricosadiyno-yl)-snglycero-3-phosphocholine (diynePC) bilayer that is a polymerizable lipid was evaluated via forced vesicle fusion in a microfluidic system. The formation of diynePC lipid bilayers in the microfluidic channel was sensitive to flow rate, and homogeneous diynePC lipid bilayers were formed when diynePC was applied at a flow rate of 0.1 μL/min for 10 min. These layers were patterned via selective photopolymerization using a UV dose of 4.1 J/cm2. Because lipids in areas blocked from UV can be selectively removed by ethanol, new lipid layers, such as egg yolk phosphatidylcholine (egg PC), that retain some characteristic features of their native cellular membrane, can be incorporated into the areas that were cleared by ethanol. This micropatterning of diynePC lipid bilayers within the microfluidic system can be used to provide a platform for a lipid-based immunoassay chip, and may therefore be a useful tool for cell based high-throughput systems.

Health Effects of Underground Workspaces cohort: study design and baseline characteristics

Gerard Dunleavy,Thirunavukkarasu Sathish,Nuraini Nazeha,Michael Soljak,Nanthini Visvalingam,Ram Bajpai,Hui Shan Yap,Adam C,Roberts,Thuan Quoc Thach,André,Comiran Tonon,Chee Kiong Soh,Georgios Ch 한국역학회 2019 Epidemiology and Health Vol.41 No.-

The development of underground workspaces is a strategic effort towards healthy urban growth in cities with ever-increasing land scarcity. Despite the growth in underground workspaces, there is limited information regarding the impact of this environment on workers’ health. The Health Effects of Underground Workspaces (HEUW) study is a cohort study that was set up to examine the health effects of working in underground workspaces. In this paper, we describe the rationale for the study, study design, data collection, and baseline characteristics of participants. The HEUW study recruited 464 participants at baseline, of whom 424 (91.4%) were followed-up at 3 months and 334 (72.0%) at 12 months from baseline. We used standardized and validated questionnaires to collect information on socio-demographic and lifestyle characteristics, medical history, family history of chronic diseases, sleep quality, health-related quality of life, chronotype, psychological distress, occupational factors, and comfort levels with indoor environmental quality parameters. Clinical and anthropometric parameters including blood pressure, spirometry, height, weight, and waist and hip circumference were also measured. Biochemical tests of participants’ blood and urine samples were conducted to measure levels of glucose, lipids, and melatonin. We also conducted objective measurements of individuals’ workplace environment, assessing air quality, light intensity, temperature, thermal comfort, and bacterial and fungal counts. The findings this study will help to identify modifiable lifestyle and environmental parameters that are negatively affecting workers’ health. The findings may be used to guide the development of more health-promoting workspaces that attempt to negate any potential deleterious health effects from working in underground workspaces.

Microwave-assisted Synthesis of Mixed Ligand Complexes of Zn(II), Cd(II) and Hg(II) Derived from 4-aminopyridine and Nitrite Ion: Spectral, Thermal and Biological Investigations

Dhaveethu, Karuthakannan,Ramachandramoorthy, Thiagarajan,Thirunavukkarasu, Kandasamy Korean Chemical Society 2013 대한화학회지 Vol.57 No.3

Zn(II), Cd(II) and Hg(II) complexes with a general composition[$M(L)_2(X)_2$], where L=4-aminopyridine (4AP) and $X=NO_2{^-}$ were prepared under microwave irradiation. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), XPS spectral and thermal studies. The spectroscopic studies reveal the composition, different modes of bonding, electronic transition, different chemical environment of C and H atoms and the electronic state of the metal atoms. On the basis of the characterization data, tetrahedral geometry is suggested for all the complexes. The free ligand (4-aminopyridine) and their metal complexes were screened against phytopathogenic fungi and bacteria in vitro and the activities were compared.

Spectroscopic, Thermal and Biological Studies of Zn(II), Cd(II) and Hg(II) Complexes Derived from 3-Aminopyridine and Nitrite Ion

Dhaveethu, Karuthakannan,Ramachandramoorthy, Thiagarajan,Thirunavukkarasu, Kandasamy Korean Chemical Society 2013 대한화학회지 Vol.57 No.6

Microwave assisted syntheses of Zn(II), Cd(II) and Hg(II) complexes with 3-aminopyridine (3AP) and nitrite ($NO_2{^-}$) ions have been reported. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), thermal and electron impact mass spectral studies. The spectroscopic studies reveal the composition, the nature of nitrite ligand in the complexes, electronic transitions, chemical environments of C and H atoms thermal degradation of the complexes. On the basis of characterization data, distorted tetrahedral geometry is suggested for Zn(II), Cd(II) and Hg(II) complexes. The organic ligand (3AP) and their metal complexes were screened against gram negative pathogenic bacteria and fungi in vitro. The results are compared with our previous report J. Korean Chem. Soc. 2013, 57, 341 on 4-aminopyridine and nitrite ion complexes of the same metal ions.