Recyclable metal nanoparticle-immobilized polymer dot on montmorillonite for alkaline phosphatase-based colorimetric sensor with photothermal ablation of Bacteria

Robby, Akhmad Irhas,Park, Sung Young Elsevier 2019 Analytica chimica acta Vol.1082 No.-

<P><B>Abstract</B></P> <P>Development of simultaneous bacteria detection and eradication with simple, rapid, and reusable material is important in addressing bacterial contamination issues. In this study, we utilized the expression of alkaline phosphatase (ALP) from bacteria to design fluorescence ON/OFF system for bacteria detection, also using metal oxide nanoparticle for obtaining antibacterial activity and recyclability. The fluorescent-based biosensor with antibacterial activity was prepared by intercalating ALP-sensitive polymer dot (PD) containing β-cyclodextrin (β-CD) onto montmorillonite (MMT) as loading matrix <I>via</I> ionic exchange reaction, followed by immobilization of magnetic iron oxide (Fe<SUB>3</SUB>O<SUB>4</SUB>) and NIR-responsive cesium tungsten oxide (CsWO<SUB>3</SUB>). The PD-βCD-MMT/Fe<SUB>3</SUB>O<SUB>4</SUB>–CsWO<SUB>3</SUB> nanocomposite exhibited strong fluorescence intensity, which was quenched in the presence of bacterial ALP (0–1000 U/L) due to hydrolysis of <I>p</I>-nitrophenyl phosphate (NPP) into <I>p</I>-nitrophenol (NP) in the hydrophobic site of β-CD. Furthermore, the nanocomposite could detect both gram-negative <I>Escherichia coli</I> and gram-positive <I>Staphylococcus aureus</I> in the range of 10<SUP>1</SUP>–10<SUP>7</SUP> CFU/mL (LOD 5.09 and 4.62 CFU/mL, respectively), and showed high antibacterial activity against bacteria by generating photothermal heat under 5 min NIR irradiation, causing damage to bacterial cells. This material also demonstrated recyclability <I>via</I> magnetic field exposure due to the presence of Fe<SUB>3</SUB>O<SUB>4.</SUB> In addition, the fluorescence can be recovered following pH shock and re-conjugation of β-CD molecules. After 4 cycles, nanocomposite still showed stable photothermal effects and fluorescence-based bacteria detection. Thus, this reusable material offers promising approach for simultaneous bacteria detection and killing, which is simple, rapid, and effective.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Reusable material was designed for fluorometric sensing and photothermolysis of bacteria. </LI> <LI> The fluorescence ON/OFF sensing system was depended on the bacterial ALP activity. </LI> <LI> The LOD of fluorescence-based bacteria detection showed below 10<SUP>1</SUP> CFU/mL. </LI> <LI> Hybrid nanocomposite showed ±100% killing efficiency after 5 min NIR irradiation. </LI> <LI> Antibacterial/bacteria sensing showed excellent performance even after 4 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

STUDY OF CORE SUPPORT BARREL VIBRATION MONITORING USING EX-CORE NEUTRON NOISE ANALYSIS AND FUZZY LOGIC ALGORITHM

ROBBY CHRISTIAN,송선호,강현국 한국원자력학회 2015 Nuclear Engineering and Technology Vol.47 No.2

The application of neutron noise analysis (NNA) to the ex-core neutron detector signal formonitoring the vibration characteristics of a reactor core support barrel (CSB) wasinvestigated. Ex-core flux data were generated by using a nonanalog Monte Carlo neutron transportmethod in a simulated CSB model where the implicit capture and Russian roulette techniquewere utilized. First and third order beam and shell modes of CSB vibration weremodeled based on parallel processing simulation. A NNA module was developed to analyzethe ex-core flux data based on its time variation, normalized power spectral density,normalized cross-power spectral density, coherence, and phase differences. The data werethen analyzed with a fuzzy logic module to determine the vibration characteristics. The ex-core neutron signal fluctuation was directly proportional to the CSB's vibrationobserved at 8Hz and15Hzin thebeammodevibration, and at 8Hz inthe shellmodevibration. The coherence result between flux pairs was unity at the vibration peak frequencies. A distinct pattern of phase differences was observed for each of the vibration models. The developed fuzzy logic module demonstrated successful recognition of the vibrationfrequencies, modes, orders, directions, and phase differences within 0.4 ms for the beamand shell mode vibrations

Factors Affecting the Distribution of Working Capital Credit

Robby Satya ANDHIKA,Iskandar MUDA,Keulana ERWIN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.6

Working Capital is an indicator of the short-term financial position of an organization and is also a measure of its overall efficiency. The growth of working capital credit for BPR in North Sumatra is not only influenced by the better performance of ROA, ROE, BOPO, and NPL, but is also influenced by the condition of the debtor’s business, existing economic conditions, and management’s assessment of the health and risk of BPR. The study aims to determine how much influence the CAR, NPL, BOPO, management assessment, ROA, ROE have on the amount of credit to be distributed by BPRs in North Sumatra, Indonesia. The study employed the time series data of published financial statements of 54 rural banks in North Sumatra from 2016 to 2019 and also employed the Chow and Hausman tests, as well as the general effect and fixed effect model specification tests. The results showed that partially the NPL, BOPO, management assessment, and ROE had a significant effect on the amount of credit to be disbursed by BPR in North Sumatra, while the variables CAR, OEOI, and ROA had a negative effect on the amount of credit to be distributed by BPR in North Sumatra. The findings also suggested that banks with a high ratio of NPL, management assessment, and ROE are more aggressive to control the working capital.

Teachers’ Training Needs for Reading Instruction : Perspectives from Teachers at English Education Centers in China

Robby Lee Robinette 아시아영어교육학회 2020 The Journal of Asia TEFL Vol.17 No.3

The Effect of Relationship Marketing on Service Quality and Customer Loyalty: An Empirical Study in Indonesia

Robby Tanod MAMUSUNG,Umar NIMRAN,Suharyono SUHARYONO,Andriani KUSUMAWATI 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.7

The purpose of this research is to examine and analyze the effect of Relationship Marketing on service quality and customer loyalty, especially in the context of the retail industry. In retail industry, Relationship Marketing is the key to increase and maintain a large pool of customers. This research was conducted in North Sulawesi Province with a sample size of 155 supermarket customers. The sampling technique used for the study is the purposive sampling. Data was analyzed using SEM based on GeSCA components. The results showed that Relationship Marketing had a significant positive effect both on service quality and customer loyalty. The commitment, communication, conflict handling, and competence play an important role in improving service quality which ultimately makes customers loyal. In addition, the relationship between service quality and customer loyalty, also has significant positive findings. These findings are in line with the concept of SERVQUAL and The Commitment-Trust Theory. The implication of the managerial research is that supermarket managers in North Sulawesi must focus and emphasize more on the Relationship Marketing dimension especially in terms of commitment, communication, conflict handling, and competence. Once these factors can be met, the quality of service will increase, and it causes an increase in customer loyalty to shop more at the supermarket.

Numerical Bayesian updating of prior distributions for concrete strength properties considering conformity control

Caspeele, Robby,Taerwe, Luc Techno-Press 2013 Advances in concrete construction Vol.1 No.1

Prior concrete strength distributions can be updated by using direct information from test results as well as by taking into account indirect information due to conformity control. Due to the filtering effect of conformity control, the distribution of the material property in the accepted inspected lots will have lower fraction defectives in comparison to the distribution of the entire production (before or without inspection). A methodology is presented to quantify this influence in a Bayesian framework based on prior knowledge with respect to the hyperparameters of concrete strength distributions. An algorithm is presented in order to update prior distributions through numerical integration, taking into account the operating characteristic of the applied conformity criteria, calculated based on Monte Carlo simulations. Different examples are given to derive suitable hyperparameters for incoming strength distributions of concrete offered for conformity assessment, using updated available prior information, maximum-likelihood estimators or a bootstrap procedure. Furthermore, the updating procedure based on direct as well as indirect information obtained by conformity assessment is illustrated and used to quantify the filtering effect of conformity criteria on concrete strength distributions in case of a specific set of conformity criteria.

Versatile Surface-coatable IR825-conjugated Fluorescent Polymer as a Dual-functional Biosensor for Synergistic Detection and Eradication of Bacteria

( Akhmad Irhas Robby ),( Sung Young Park ) 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1

A software tool for integrated risk assessment of spent fuel transportation and storage

Mirae Yun,Robby Christian,김보경,Belal Almomani,Jaehyun Ham,이상훈,강현국 한국원자력학회 2017 Nuclear Engineering and Technology Vol.49 No.4

When temporary spent fuel storage pools at nuclear power plants reach their capacity limit, the spentfuel must be moved to an alternative storage facility. However, radioactive materials must be handledand stored carefully to avoid severe consequences to the environment. In this study, the risks of threepotential accident scenarios (i.e., maritime transportation, an aircraft crashing into an interim storagefacility, and on-site transportation) associated with the spent fuel transportation process were analyzedusing a probabilistic approach. For each scenario, the probabilities and the consequences were calculatedseparately to assess the risks: the probabilities were calculated using existing data and statistical models,and the consequences were calculated using computation models. Risk assessment software wasdeveloped to conveniently integrate the three scenarios. The risks were analyzed using the developedsoftware according to the shipment route, building characteristics, and spent fuel handling environment. As a result of the risk analysis with varying accident conditions, transportation and storage strategieswith relatively low risk were developed for regulators and licensees. The focus of this study was the riskassessment methodology; however, the applied model and input data have some uncertainties. Furtherresearch to reduce these uncertainties will improve the accuracy of this model.

Bayesian updated correlation length of spatial concrete properties using limited data

Pieterjan Criel,Robby Caspeele,Luc Taerwe 사단법인 한국계산역학회 2014 Computers and Concrete, An International Journal Vol.13 No.5

A Bayesian response surface updating procedure is applied in order to update the parameters of the covariance function of a random field for concrete properties based on a limited number of available measurements. Formulas as well as a numerical algorithm are presented in order to update the parameters of response surfaces using Markov Chain Monte Carlo simulations. The parameters of the covariance function are often based on some kind of expert judgment due the lack of sufficient measurement data. However, a Bayesian updating technique enables to estimate the parameters of the covariance function more rigorously and with less ambiguity. Prior information can be incorporated in the form of vague or informative priors. The proposed estimation procedure is evaluated through numerical simulations and compared to the commonly used least square method.

Strain and crack development in continuous reinforced concrete slabs subjected to catenary action

Dirk Gouverneur,Robby Caspeele,Luc Taerwe 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.1

Several structural calamities in the second half of the 20th century have shown that adequatecollapse-resistance cannot be achieved by designing the individual elements of a structure without taking their interconnectivity into consideration. It has long been acknowledged that membrane behaviour of reinforced concrete structures can significantly increase the robustness of a structure and delay a complete collapse. An experimental large-scale test was conducted on a horizontally restrained, continuous reinforced concrete slab exposed to an artificial failure of the central support and subsequent loading until collapse of the specimen. Within this investigation the development of catenary action associated with the formation of large displacements was observed to increase the ultimate load capacity of the specimen significantly. The development of displacements, strains and horizontal forces within this investigation confirmed a load transfer process from an elastic bending mechanism to a tension controlled catenary mechanism. In this contribution a special focus is directed towards strain and crack development at critical sections. The results of this contribution are of particular importance when validating numerical models related to the development of catenary action in concrete slabs.