Template-Free Growth of Novel Hydroxyapatite Nanorings: Formation Mechanism and Their Enhanced Functional Properties

Nathanael, A. Joseph,Hong, Sun Ig,Mangalaraj, D.,Ponpandian, N.,Chen, Pao Chi American Chemical Society 2012 Crystal Growth & Design Vol.12 No.7

<P>Template-free, single crystalline novel hydroxyapatite (HAp) nanorings with an inner diameter of 70 nm were grown by a combined high gravity and hydrothermal approach. Nanodisks were suggested to be formed by oriented aggregation and Ostwald ripening of mostly calcium pyrophosphate nanospheres prepared initially by the high gravity method with a stepwise increase of flow rate of phosphate solution. The prolonged hydrothermal treatment of nanodisks appeared to induce the nanoring formation via acid penetration along the dislocations in HAp nanodisks. The presence of edge dislocations in the central region of nanodisks was confirmed by high resolution transmission electron microscopy. The mechanical evaluation of high molecular weight polyethylene (HMWPE) composite with various shaped HAp nanocrystals and in vitro cellular analysis of HAp nanocrystals revealed that mechanical and bioactive performances improved with an increase of the specific surface area of HAp nanocrystals. The enhanced mechanical performance of HMWPE/HAp nanoring composite and the excellent cell viability for HAp nanorings are attributed to the superior interface bonding and cell activity, respectively, both of which are enhanced by the high specific surface area.</P><P>This work describes the template free growth mechanism and the enhanced properties of novel hydroxyapatite nanorings. Formation of nanodisk was explained by initial oriented aggregation and Ostwald ripening. Nanoring formation was suggested to be induced by acid penetration along the dislocations. Mechanical and in vitro analysis proved the enhanced functional properties of this novel structure.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2012/cgdefu.2012.12.issue-7/cg3003959/production/images/medium/cg-2012-003959_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cg3003959'>ACS Electronic Supporting Info</A></P>

PVP Assisted Synthesis of Hydroxyapatite Nanorods with Tunable Aspect Ratio and Bioactivity

Nathanael, A. Joseph,Seo, Young Ho,Oh, Tae Hwan Hindawi Limited 2015 Journal of nanomaterials Vol.2015 No.-

<P>Highly crystalline and reasonably uniform hydroxyapatite (HA) nanorods were prepared by polyvinylpyrrolidone (PVP) assisted hydrothermal synthesis which produces high aspect ratio (length/width) nanorods. The aspect ratio of the nanorods was higher in the presence of PVP and increased with increasing concentrations of PVP. X-ray diffraction (XRD) analysis showed that the HA nanorods were of the hexagonal apatite phase. High resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) patterns confirmed that the nanorods grew in the<I>c</I>-axis direction (preferred orientation). The calculated lattice spacing was ~0.35 nm which is the<I>c</I>-axis value of hexagonal HA. Morphological variations of pristine and PVP added HA were evaluated by field emission scanning electron microscopy (FESEM) and TEM, which revealed that the presence of PVP greatly increased the aspect ratio of the HA nanorods. The formation mechanism of the PVP assisted HA was studied and a possible reaction model was given. Cell viability analysis by<I>in vitro</I>studies showed encouraging results for the high aspect ratio nanorods and indicated a possibility for tuning the activity based on controlling the aspect ratio.</P>

Novel Zirconium Nitride and Hydroxyapatite Nanocomposite Coating: Detailed Analysis and Functional Properties

Nathanael, A. Joseph,Yuvakkumar, R.,Hong, Sun Ig,Oh, Tae Hwan American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.12

<P>A new type of high-quality zirconium nitride (ZrN) and hydroxyapatite (HA) bionanocomposite was prepared by radio-frequency (RF) magnetron sputtering for biomedical applications. Detailed analysis of this composite coating revealed that a higher substrate temperature (ST) (>300 °C) increased its crystallinity, uniformity, and functional properties. This nanocomposite showed some encouraging functional properties. Mechanical analyses of the nanocomposite showed improved hardness, modulus, and wear resistance, which were found to be due to the increasing volume fraction of ZrN at higher ST. Biomineralization and in vitro cell analysis revealed increased weight gain and enhanced cell activity with increased substrate temperature. Overall, the results of the present study indicate that this nanocomposite coating could become a promising alternative for biomedical applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-12/am5023557/production/images/medium/am-2014-023557_0014.gif'></P>

Evaluating Antibody Structure Reconstruction with an SE(3)-Equivariant Graph Neural Network

Bryan Nathanael Wijaya,Luiz Felipe Vecchietti,Meeyoung Cha(차미영),Ho Min Kim(김호민) 한국정보과학회 2023 한국정보과학회 학술발표논문집 Vol.2023 No.12

ETHNIC AND RELIGIOUS SENTIMENTS IN INDONESIAN POLITICS: EVIDENCE FROM THE 2017 JAKARTA GUBERNATORIAL ELECTION

Sumaktoyo Nathanael Gratias 동아시아연구원 2021 Journal of East Asian Studies Vol.21 No.1

Studies have documented how ethnic and religious sentiments shape the voting behavior of Indonesian Muslims. However, to date no studies have carefully measured the relative influence of these sentiments. I fill this gap in the literature by taking advantage of the candidacy of a Christian, ethnic Chinese candidate in the 2017 Jakarta gubernatorial election in Basuki Tjahaja Purnama (Ahok). Employing an original survey of Jakartan Muslims, I show through experimental and correlational analyses that Muslim voters are more opposed to Ahok than non-Muslim voters are and that this opposition is driven more by Ahok's ethnicity, as opposed to his religion. I also show that Muslim voters’ feelings toward ethnic Chinese shape their support for Ahok more than their feelings toward Christians. I discuss how these findings inform our understanding of the limits and extent of religious influence on Muslim voting behavior.

Information Hiding in Noncoding DNA for DNA Steganography

SANTOSO, Kevin Nathanael,LEE, Suk-Hwan,HWANG, Won-Joo,KWON, Ki-Ryong 'Institute of Electronics, Information and Communi 2015 IEICE transactions on fundamentals of electronics, Vol.ea98 No.7

Smart government framework with geo-crowdsourcing and social media analysis

Witanto, Joseph Nathanael,Lim, Hyotaek,Atiquzzaman, Mohammed North-Holland 2018 Future generations computer systems Vol.89 No.-

<P><B>Abstract</B></P> <P>Smart government utilizes data to improve services provided to the citizen. Smart city may benefit from citizen engagement through crowdsourcing and social media. This paper proposes a city event’s prediction with map-based visualization utilizing crowdsourced geodata collected from citizen’s report. Data is aggregated according to geo-position and used to predict next day’s event. Mindmap-based visualization utilizing social media processed with topic modeling and topic similarity calculation is also proposed in this work. Proof-of-concept application and proposed system’s processing time is evaluated to prove the feasibility of the system. Proposed system utilizes geo-crowdsourcing for event prediction visualization for government instead of direct services to citizen. Proposed social media visualization use topic modeling specifically created for short text which is appropriate for social media data.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Proposes map-based reporting for government-related activities based on geo-crowdsourced data. </LI> <LI> Proposes mindmap-based reporting for social media analysis. </LI> <LI> Evaluates smart city frameworks, geo-crowdsourcing and social media analysis applications. </LI> </UL> </P>

Adaptive selection of dynamic VM consolidation algorithm using neural network for cloud resource management

Witanto, Joseph Nathanael,Lim, Hyotaek,Atiquzzaman, Mohammed Elsevier 2018 Future generation computer systems Vol.87 No.-

<P><B>Abstract</B></P> <P>Cloud resource management becomes more important with the increasing usage of cloud resources. With various cloud options available, cloud provider may have different priority in managing the resource through resource scheduling and provisioning. Dynamic VM (Virtual Machine) consolidation algorithm is one of the techniques which can be used to reduce energy consumption through VM migration. Higher VM migration may lead to lower energy consumption and higher SLA violation. Although previous research has successfully decreased energy consumption and SLA violation, cloud providers may need to manage trade-offs between energy and SLA violation through availability of priority in the system. This paper proposes neural network-based adaptive selection of VM consolidation algorithms which adaptively chooses appropriate algorithm according to cloud provider’s goal priority and environment parameters. Dataset generation and performance evaluation using simulations on real-world PlanetLab VMs workload trace showed that adaptive selector produced better average performance score than independent methods on various evaluation priority.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Studies on multiple dynamic VM consolidation algorithms on cloud environment. </LI> <LI> Discusses about trade-off between energy and SLA violation due to VM migration. </LI> <LI> Proposes adaptive system which chooses best algorithm based on provider’s priority. </LI> <LI> Evaluates performance of proposed system and individual VM migration algorithms. </LI> </UL> </P>

The Complex Interrelationship of Work-Related Factors Underlying Risky Driving Behavior of Food Delivery Riders in Athens, Greece

Papakostopoulos, Vassilis,Nathanael, Dimitris Occupational Safety and Health Research Institute 2021 Safety and health at work Vol.12 No.2

Background: In this study, the association of work and demographic characteristics with different traffic offenses committed by food delivery riders in Greece was examined. Previous research has identified various factors related to risky driving however, there is a need for exploring the complex interrelationship of work-related factors underlying risky driving behavior. Materials and Methods: A 2-items uestionnaire was used exploring delivery riders demographic characteristics, terms of employment, issues of concern during work and type of traffic offenses committed. In total, uestionnaires were analyzed using logistic regression in order to identify characteristics independently associated with serious traffic offenses, namely, red-light running and helmet non-use. Results: The analysis showed that: (i) typical health and safety measures had no effect on serious traffic offenses, (ii) young age was related to both offenses however (iii) different sets of work conditions were associated with reports of red-light running (i.e. low work experience, use of personal vehicle for work, and payment by hour) and helmet non-use respectively (i.e. intense work pace, high tip income per day and low concern about vehicle condition). Conclusion: The above findings provide evidence that serious traffic offenses are manifestations of underlying conflict experienced by the riders between safety and various performance criteria. Each one of the two offenses is related to different rider profiles aiming to satisfy different goals, namely, those mainly trying to maximize profit non-helmet users and those, mostly inexperienced ones, trying to cope with work pressure red light runners. Potential regulatory measures to alleviate risky practices are discussed.

Rice husk ash nanosilica to inhibit human breast cancer cell line (3T3)

Yuvakkumar, R.,Nathanael, A. Joseph,Rajendran, V.,Hong, S. I. Springer-Verlag 2014 Journal of sol-gel science and technology Vol.72 No.1