In-situ XPS study of ALD ZnO passivation of p-In0.53Ga0.47As

Lucero, A. T.,Byun, Y. C.,Qin, X.,Cheng, L.,Kim, H.,Wallace, R. M.,Kim, J. SPRINGER SCIENCE AND BUSINESS MEDIA 2015 ELECTRONIC MATERIALS LETTERS Vol.11 No.5

Formation of a ZnO/ZnS interface passivation layer on (NH₄)₂S treated In_0.53Ga_0.47As: Electrical and in-situ X-ray photoelectron spectroscopy characterization

Lucero, Antonio T.,Byun, Young-Chul,Qin, Xiaoye,Cheng, Lanxia,Kim, Hyoungsub,Wallace, Robert M.,Kim, Jiyoung Institute of Pure and Applied Physics 2016 Japanese Journal of Applied Physics Vol. No.

<P>Atomic layer deposition is used to convert an (NH4)(2)S cleaned p-In0.53Ga0.47As with diethylzinc (DEZ) and water, resulting in the formation of a ZnO/ZnS interfacial passivation layer (IPL). The process is studied using in-situ X-ray photoelectron spectroscopy. DEZ reacts with sulfur and oxygen present on the surface, chemically reducing arsenic 3+ and gallium 3+ to lower oxidation states. The sulfur concentration remains constant during the deposition process while the oxygen concentration on the surface remains small, confirming that the IPL is composed of both ZnO and ZnS. Measurements of metal-oxide-semiconductor capacitors with HfO2 for the dielectric show that the ZnO/ZnS IPL can nearly eliminate frequency dispersion (<1% per frequency decade) in accumulation and results in small hysteresis (<60 mV) with a Dit in the 10(11) eV(-1) cm(-2) range in the midgap. Frequency dispersion is observed in the depletion region and is attributed to minority carrier generation from the ZnO present in the IPL. (C) 2016 The Japan Society of Applied Physics</P>

Parameter Optimization for Cost Reduction of Microbubble Generation by Electrolysis

( Arpon Lucero Jr ),( Dong-seog Kim ),( Young-seek Park ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.3

To lower the operational cost of microbubble generation by electrolysis, optimization of parameters limiting the process must be carried out for the process to be fully adopted in environmental and industrial settings. In this study, four test electrodes were used namely aluminum, iron, stainless steel, and Dimensionally Sable Anode (DSA). We identified the effects and optimized each operational parameter including NaCl concentration, current density, pH, and electrode distance to reduce the operational cost of microbubble generation. The experimental results showed that was directly related to the rate and cost of microbubble generation. Adding NaCl and narrowing the distance between electrodes caused no substantial changes to the generation rate but greatly decreased the power requirement of the process, thus reducing operational cost. Moreover, comparison among the four electrodes operating under optimum conditions revealed that aluminum was the most efficient electrode in terms of generation rate and operational cost. This study therefore presents significant data on performing costefficient microbubble generation, which can be used in various environmental and industrial applications.

Effect of Operational Parameters on the Removal of Microcystis aeruginosa in Electro-flotation Process

( Arpon Lucero Jr ),( Dong-seog Kim ),( Young-seek Park ) 한국환경과학회 2016 한국환경과학회지 Vol.25 No.10

Despite the low removal efficiencies reported by previous studies, electro-flotation still stands out among other microalgae removal methods for its economical and environmental benefits. To enhance removal efficiency, the important factors that limit the performance of this method must be investigated. In this study, the possible ways of increasing the removal efficiency of microalgae have been explored by investigating the effects of several important variables in electro-flotation. Eight parameters, namely flotation time, rising time, current density, pH, conductivity, electrode distance, temperature and initial concentration were evaluated using a one-parameter-at-a-time approach. Results revealed that the operational parameters that greatly affected the removal efficiency of microalgae were electro-flotation time, current density, pH, and initial concentration. The effect of conductivity, electrode distance, and temperature on removal efficiency were insignificant. However, they exhibited positive an indirect positive effect on power demand, which is nowadays considered an equally important aspect in the running of a feasible and economically efficient electro-flotation process.

Hanging Out with Kids Who Accept Them for Who They Are: Using Queer Theory to Understand How Youth Challenge Norms and Explore Identities

Thomas Rhianna,Lucero Leanna,Owens Angela,Cahill Betsy 한국다문화교육학회 2022 Multicultural Education Review Vol.14 No.1

Youth are social actors who not only engage in but transform culture. Promoting plurality often means letting go of preconceived notions of power in youth social circles. Here, we utilize parent-child ethnography and the lens of queer theory to analyse four stories of youth identity exploration and answer the following research questions: 1) how do these youth, as social actors, challenge, recreate, or fit into dominant social structures, and 2) how do adults, who interact with youth, constrain and expand youth opportunities for identity development that run counter to norms. The stories and counterstories offer examples of youth social agency that disrupts dominant norms around sexuality, gender, and race. In lieu of implications, we offer considerations around facilitating conversations grounded in youth experiences, creating space for youth to question norms, and meeting youth’s need for belonging.

Predictors and Prevalence of Alcohol and Cannabis Co-use Among Filipino Adolescents: Evidence From a School-based Student Health Survey

Adebisi Yusuff Adebayo,Lucero-Prisno III Don Eliseo,Ogaya Jerico B.,Cañezo Victor C.,Niez Roland A.,Delos Santos Florante E.,Magramo Melchor M.,Yap-Tan Ann Rosanie,Sy Francis Ann R.,Kasimieh Omar 대한예방의학회 2024 예방의학회지 Vol.57 No.3

Objectives: This study explored the prevalence and predictors of alcohol and cannabis co-use among 9263 Filipino adolescents, using data from the 2019 Global School-based Student Health Survey (GSHS).Methods: We conducted a cross-sectional secondary analysis of the GSHS, targeting adolescents aged 13-17 years and excluding cases with incomplete data on alcohol and cannabis use. Our analysis employed the bivariate chi-square test of independence and multivariable logistic regression using Stata version 18 to identify significant predictors of co-use, with a p-value threshold set at 0.05.Results: The weighted prevalence of co-users was 4.2% (95% confidence interval [CI], 3.4 to 5.3). Significant predictors included male sex (adjusted odds ratio [aOR], 4.50; 95% CI, 3.31 to 6.10; p<0.001) and being in a lower academic year, specifically grade 7 (aOR, 4.08; 95% CI, 2.39 to 6.99; p<0.001) and grade 8 (aOR, 2.20; 95% CI, 1.30 to 3.72; p=0.003). Poor sleep quality was also a significant predictor (aOR, 1.77; 95% CI, 1.29 to 2.44; p<0.001), as was a history of attempted suicide (aOR, 5.31; 95% CI, 4.00 to 7.06; p<0.001). Physical inactivity was associated with lower odds of co-use (aOR, 0.45; 95% CI, 0.33 to 0.62; p<0.001). Additionally, non-attendance of physical education classes (aOR, 1.48; 95% CI, 1.06 to 2.05; p=0.021), infrequent unapproved parental checks (aOR, 1.37; 95% CI, 1.04 to 1.80; p=0.024), and lower parental awareness of free-time activities (aOR, 0.63; 95% CI, 0.45 to 0.87; p=0.005) were associated with higher odds of co-use. Factors not significantly linked to co-use included age group, being in grade 9, always feeling lonely, having no close friends, being bullied outside school, and whether a parent or guardian understood the adolescent’s worries.Conclusions: The findings highlight the critical need for comprehensive interventions in the Philippines, addressing not only physical inactivity and parental monitoring but also focusing on sex, academic grade, participation in physical education classes, sleep quality, and suicide attempt history, to effectively reduce alcohol and cannabis co-use among adolescents.

One-dimensional Nanomaterials for Field Effect Transistor (FET) Type Biosensor Applications

Mingun Lee,김지영,Antonio Lucero 한국전기전자재료학회 2012 Transactions on Electrical and Electronic Material Vol.13 No.4

One-dimensional, nanomaterial field effect transistors (FET) are promising sensors for bio-molecule detection applications. In this paper, we review fabrication and characteristics of 1-D nanomaterial FET type biosensors. Materials such as single wall carbon nanotubes, Si nanowires, metal oxide nanowires and nanotubes, and conducting polymer nanowires have been widely investigated for biosensors, because of their high sensitivity to bio-substances,with some capable of detecting a single biomolecule. In particular, we focus on three important aspects of biosensors:alignment of nanomaterials for biosensors, surface modification of the nanostructures, and electrical detection mechanism of the 1-D nanomaterial sensors.

Anti-Inflammatory Action of Blueberry Polyphenols in HIG-82 Rabbit Synoviocytes

Sanique South,Jacquelynn Lucero,Parakat Vijayagopal,Shanil Juma 한국식품영양과학회 2019 Journal of medicinal food Vol.22 No.10

Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory disease resulting in joint destruction and disability in the adult population. The etiology of RA is not well understood and presently there is no known cure for this disease. The accumulation and proliferation of fibroblast-like synoviocytes may be involved in cartilage destruction. Both in vitro and in vivo studies support an anti-inflammatory role of dietary polyphenols, the bioactive constituents found in fruits and vegetables. The objective of this study was to investigate the anti-inflammatory role of blueberry polyphenols (BBPs) using rabbit synoviocytes stimulated with tumor necrosis factor alpha (TNFα). Rabbit synoviocytes (HIG-82) were treated with varying doses of BBPs and stimulated with TNFα. Stimulation of rabbit synoviocytes with the proinflammatory cytokine TNFα increased cell proliferation by ∼19% compared with the nonstimulated control. Cell proliferation was significantly decreased in a dose-dependent manner by the treatment with BBPs. Post-TNFα stimulation, cells treated with BBPs resulted in decreases in interleukin 1 beta and nuclear factor kappa B (NFκB) concentration. Reverse transcription–polymerase chain reaction analysis showed that matrix metalloproteinase 3 increased fivefold in the control TNFα-stimulated group, but was decreased by threefold in the blueberry treatment group. These results suggest that downregulation of proinflammatory cytokines and transcription factor NFκB by naturally occurring bioactives such as BBPs may be a potential therapeutic strategy for reducing inflammation associated with RA.

Low temperature synthesis of graphite on Ni films using inductively coupled plasma enhanced CVD

Cheng, Lanxia,Yun, Kayoung,Lucero, Antonio,Huang, Jie,Meng, Xin,Lian, Guoda,Nam, Ho-Seok,Wallace, Robert M.,Kim, Moon,Venugopal, Archana,Colombo, Luigi,Kim, Jiyoung The Royal Society of Chemistry 2015 Journal of Materials Chemistry C Vol.3 No.20

<▼1><P>Synthesis of good quality graphite on Ni using IC-PECVD at a low temperature of 380 °C in a hydrogen free environment.</P></▼1><▼2><P>Controlled synthesis of graphite at low temperatures is a desirable process for a number of applications. Here, we present a study on the growth of thin graphite films on polycrystalline Ni films at low temperatures, about 380 °C, using inductively coupled plasma enhanced chemical vapor deposition. Raman analysis shows that the grown graphite films are of good quality as determined by a low <I>I</I>D/<I>I</I>G ratio, ∼0.43, for thicknesses ranging from a few layers of graphene to several nanometer thick graphitic films. The growth of graphite films was also studied as a function of time, precursor gas pressure, hydrogen concentration, substrate temperature and plasma power. We found that graphitic films can be synthesized on polycrystalline thin Ni films on SiO2/Si substrates after only 10 seconds at a substrate temperature as low as 200 °C. The amount of hydrogen radicals, adjusted by changing the hydrogen to methane gas ratio and pressure, was found to dramatically affect the quality of graphite films due to their dual role as a catalyst and an etchant. We also find that a plasma power of about 50 W is preferred in order to minimize plasma induced graphite degradation.</P></▼2>

One-dimensional Nanomaterials for Field Effect Transistor (FET) Type Biosensor Applications

Lee, Min-Gun,Lucero, Antonio,Kim, Ji-Young The Korean Institute of Electrical and Electronic 2012 Transactions on Electrical and Electronic Material Vol.13 No.4

One-dimensional, nanomaterial field effect transistors (FET) are promising sensors for bio-molecule detection applications. In this paper, we review fabrication and characteristics of 1-D nanomaterial FET type biosensors. Materials such as single wall carbon nanotubes, Si nanowires, metal oxide nanowires and nanotubes, and conducting polymer nanowires have been widely investigated for biosensors, because of their high sensitivity to bio-substances, with some capable of detecting a single biomolecule. In particular, we focus on three important aspects of biosensors: alignment of nanomaterials for biosensors, surface modification of the nanostructures, and electrical detection mechanism of the 1-D nanomaterial sensors.