Investigation of thermal energy potential, pyroelectric, and electrocaloric performance of Ba0.7Ca0.3TiO3 ceramic

Ray A.,Nayak B.,Elorika P.,Barman R.,Sharmistha A.,Badapanda T.,Anwar S. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

In the current work, the structural, dielectric, and electrocaloric performance of Ba0.7Ca0.3TiO3 ceramic synthesized by solid-state reaction route is presented. The structural analysis was examined by X-ray diffraction and Rietveld refinement, which confirms the existence of a combined phase of tetragonal structure with P4mm symmetry and orthorhombic structure with Amm2 symmetry. The scanning electron micrograph shows well-defined and pore-free grains. The temperature-dependent dielectric performance shows diffuse phase transition behavior. The temperature-dependent ferroelectric hysteresis behavior was examined under the application of various amplitudes of an applied electric field. The energy storage density, energy loss density, and energy storage efficiency of the composition at different temperature were calculated using the standard formula. The thermal energy potential has been calculated by employing the Olsen cycle. Also, pyroelectric figures of merit (FOMs) for voltage responsivity (Fv), current responsivity (Fi), energy harvesting (Fe), new energy harvesting (F*e), and detective (Fd) were calculated. Adiabatic temperature change, isothermal entropy change, and electrocaloric strength are evaluated using an indirect technique based on the thermodynamic Maxwell's relation.

A review of gas sensors based on carbon nanomaterial

Raya Indah,Kzar Hamzah H.,Mahmoud Zaid Hameed,Al Ayub Ahmed Alim,Ibatova Aygul Z.,Kianfar Ehsan 한국탄소학회 2022 Carbon Letters Vol.32 No.2

As a new nanostructure, a graphene is a compound of carbon atoms with a two-dimensional structure that has attracted the attention of many nanoscale researchers due to its novel physical and chemical properties. The presence of all graphene atoms in the surface and its unique electrical properties, as well as the ability to functionalize and combine with another nanomaterial, has introduced graphene as a new and suitable candidate material for gas sensing. Over the years, many researchers have turned their attention to carbon nanomaterial. The unique optical, mechanical, and electronic properties of these nanostructures have led them to use these nanomaterials to develop tiny devices, such as low-consumption sensors. Carbon nanomaterial poses a threat to another nanomaterial in terms of their use in gas sensors. This review article discusses the use of carbon nanoparticles and graphene in gas sensors, examines the nodes in the commercialization pathway of these compounds, and presents the latest achievements. Finally, the perspectives of the challenges and opportunities in the field of sensors based on carbon nanomaterial and graphene are examined.

Performance of High Strength Self-Compacting Concrete Beams under Different Modes of Failure

Raya Hassan Harkouss,Bilal Salim Hamad 한국콘크리트학회 2015 International Journal of Concrete Structures and M Vol.9 No.1

Self-consolidating concrete (SCC) is a stable and cohesive high consistency concrete mix with enhanced filling ability properties that reduce the need for mechanical compaction. Limited standards and specifications have been reported in the literature on the structural behavior of reinforced self-compacting concrete elements. The significance of the research presented in this paper stems from the need to investigate the effect of enhanced fluidity of SCC on the structural behavior of high strength selfconsolidating reinforced concrete beams. To meet the objectives of this research, twelve reinforced concrete beams were prepared with two different generations of superplasticizers and designed to exhibit flexure, shear, or bond splitting failure. The compared beams were identical except for the type of superplasticizer being used (second generation sulphonated-based uperplasticizer or third generation polycarboxylate-based superplasticizer). The outcomes of the experimental work revealed comparable resistance of beam specimens made with self-compacting (SCC) and conventional vibrated concrete (VC). The dissimilarities in the experimental values between the SCC and the control VC beams were not major, leading to the conclusion that the high flowability of SCC has little effect on the flexural, shear and bond strengths of concrete members.

“The Persistence of Parent Repayment” and the Anticipation of Filial Obligations of Care in Two Thai Provinces

Stuart Basten,Raya Muttarak,Wiraporn Pothisiri 한국사회복지학회 2014 Asian Social Work and Policy Review Vol.8 No.2

With an accelerated and sustained decline in fertility and an increase in life expectancy, Thailandhas entered its aging phase at a rapid pace. This raises an important question of who should carefor the increasing elderly population. Using a survey of adults aged 16–64 years (n = 742) in twoprovinces in the north-east (Kalasin) and south (Phang Nga) of Thailand, this paper explores theexpectations that individuals have from their children when they become very old. Only one-thirdof the respondents expected to live with their children in old age and only one-fifth anticipatedfinancial assistance. Less than half of them expected personal care and practical care from theirchildren (43% and 38%, respectively). The expectations varied substantially by the number of childrenand income, with those with higher income reporting lower expectation. Those living in Kalasin,a much poorer province than Phang Nga, had greater expectations from their children in oldage. This suggests that, for those with less financial resources, children remain the main care providerfor the elderly.

Peptide Receptor Radionuclide Therapy and the Treatment of Gastroentero-pancreatic Neuroendocrine Tumors: Current Findings and Future Perspectives

Hirmas, Nader,Jadaan, Raya,Al-Ibraheem, Akram 대한핵의학회 2018 핵의학 분자영상 Vol.52 No.3

Purpose and Methods Patients with inoperable and metastasized neuroendocrine tumors (NETs), particularly those with grades 1 and 2, usually receive treatment with somatostatin analogues (SSAs). Peptide receptor radionuclide therapy (PRRT) has gained momentum over the past two decades in patients who progress on SSAs. 177Lu-DOTATATE is currently the most widely used radiopeptide for PRRT. We reviewed the recent evidence on PRRT and the treatment of gastroentero-pancreatic neuroendocrine tumors (GEP-NETs). Results $^{177}Lu$-DOTATATE can be used as neoadjuvant treatment in patients with inoperable GEP-NETs, who might be candidate for surgery after treatment and as adjuvant therapy after surgical intervention. Combination treatments of PRRT with chemotherapy or targeted agents as well as combinations of radionuclides in patients with NETs have been explored over the last few years. The majority of patients with NETs experience partial response or have disease stabilization, a small percentage has complete response, while some 30% of patients, however, will have disease progression. The safety and efficacy of retreatment with extra cycles of PRRT as salvage therapy have been evaluated in small retrospective series. Conclusion Overall, there is evidence that disease control and quality of life improve significantly after 117Lu PRRT therapy. Clinical trials on this therapy are scarce, and there is a need for further studies to establish proper management guidelines.

Poster Session:PS 0564 ; Palliative Care : Asian Late Period of Adolescents Did Not Want Life-Sustaining Managements

( Young Joo Lee ),( Lukman Raya Praja ),( Yogi Agung Prima Wardhana ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Late period of adolescents with terminal cancer would participate in end of life (EOL) issues decision-making to improve their quality of life, though they have their parents as legal decision makers. We studied to understand the attitudes and preference of Korean adolescents about EOL issues. Methods: 16-17 years old healthy high school students (n= 238) in Korea were enrolled. Participants answered the questions eliciting views on EOL issues and indicating their position regarding hypothetical scenarios concerning physician assisted suicide (PAS). The questionnaire was developed based on previously published studies designed for survey adults` or college students` attitudes toward EOL issues. Data were analyzed with SPSS including fisher`s exact test. Results: The vast majority (89.9 %) have thought about EOL issue; more females (94.9%) than males (83.0%) (P=0.004), and more Christians (95.3%) than those not having religion (87.1%) (P=0.036). Minority of the responders (23.9%) want to receive life-sustaining management when they become terminally ill, more males (31.0%) than females (19.8%) (P=0.032). Most students (85.1%) agreed to prepare advance directive. The responders considered the best timing for complete advance directives are; when terminally ill without hope of recovery (41.6%) > before getting sick, while healthy (21.0%) > fi rst diagnosed as critical diseases (16.0%) > impending to death (11.8%). Responder`s position with regard to PAS scenario differs depends on the patient`s condition (P <0.001). Although 75.6% of responders agreed with PAS for terminally ill patients with uncontrollable pain, only 58.0% agreed with PAS for those patients without pain. Conclusions: Most Asian adolescents have thought of EOL issue and did not want life-sustaining managements in terminal situation. Attitudes toward PAS changed depending on the patient`s situation.

Allometric models and aboveground biomass of Lumnitzera racemosa Willd. forest in Rawa Aopa Watumohai National Park, Southeast Sulawesi, Indonesia

Analuddin Kangkuso,Jamili Jamili,Andi Septiana,Rasas Raya,Idin Sahidin,Usman Rianse,Saban Rahim,Alfirman Alfirman,Sahadev Sharma,Kazuo Nadaoka 한국산림과학회 2016 Forest Science And Technology Vol.12 No.1

Information on aboveground biomass of mangrove forest at Rawa Aopa Watumohai National (RAWN) Park is fundamental for the management of mangroves (Lumnitzera racemosa Willd.) in the park. Allometric relationships of partial or whole L. racemosa trees were examined using independent variables D30, DBH, and DB or quadratics D302H, DBH2H, and DB2H from different individuals of L. racemosa trees. Aboveground biomass was estimated by allometric equations and tree census data. Results showed that the best fit for allometric models of stem biomass (WS) and leaf biomass (WL) used the independent variable of DBH2H, while the best fit for branch biomass (WB) used quadratic DB2H. The quadratic DBH2H is the most reliable parameter for estimating aboveground biomass of L. racemosa trees. Aboveground biomass of L. racemosa varied among stands, ranging from 26.23 to 191.01 ton ha ¡1. Biomass density of L. racemosa forest varied from 4.07 to 29.80 ton ha ¡1 m ¡1. The high aboveground biomass of L. racemosa indicates its high blue carbon stock, which maintains the productivity of nearby coastal areas. Therefore, the results of this study can help the sustainable management of mangroves in the RAWN Park and surrounding areas.

Over-education and its opportunity cost in Japan

Aleksander Kucel,Ivette Fuentes Molina,Josep Maria Raya 서울대학교 교육연구소 2016 Asia Pacific Education Review Vol.17 No.2

In this paper, we investigate the determinants of over-education in Japan and evaluate its opportunity costs for university graduates. To this end, we use the REFLEX data. Results reveal that over-education level in Japan is high and it brings an important wage penalty for Japanese workers. Large firm and high occupations point toward a significant reduction in the likelihood of over-education. Results for wage regressions for over-education indicate that Japanese workers who achieve jobs in large organizations will experience 20 % increase in their wage due to the firm size and, if over-educated, their increase in wage will remain positive. Results for women are puzzling as there is no significant effect associated with gender.

Enterococcus faecium Isolated from Honey Synthesized Bacteriocin-Like Substances Active against Different Listeria monocytogenes Strains

Carolina Ibarguren,M. Carina Audisio,Raúl R. Raya,María C. Apella 한국미생물학회 2010 The journal of microbiology Vol.48 No.1

Four Enterococcus faecium strains, isolated from honeycombs (C1 and M2d strains) and feral combs (Mori1and M1b strains) secreted antimicrobial substances active against fourteen different Listeria spp. strains. The antimicrobial compound(s) present in the cell free supernatant were highly thermostable (121°C for 15 min) and inactivated by proteolytic enzymes, but not by α-amylase and lipase, thus suggesting a peptidic nature. Since the structural bacteriocin gene determinants of enterocins A and B were PCR amplified from the four E. faecium isolates, only the bacteriocin produced by strain C1 was further characterized: it showed a broad band of approximately 4.0-7.0 kDa in SDS-PAGE and was bactericidal (4 log decrease) against L. monocytogenes 99/287. L. monocytogenes 99/287R, a clone spontaneously resistant to the enterocin produced by E. avium DSMZ17511 (ex PA1), was not inhibited by the enterocin-like compounds produced by strain C1. However, it was inhibited in mixed culture fermentations by E. faecium C1 and a bacteriostatic effect was observed. The bacteriocin-producer Enterococcus strains were not haemolytic; gelatinase negative and sensitive to vancomycin and other clinically relevant antibiotics.

The Protective Effect of Curcumin against Nitrosamine-Induced Gastric Oxidative Stress in Rats

Mostafa Ibrahim Waly,Ismail M. Al-Bulushi,Shaimaa Al-Hinai,Nejib Guizani,Raya Nasser Al-Malki,Mohammad Shafiur Rahman 한국식품영양과학회 2018 Preventive Nutrition and Food Science Vol.23 No.4

Curcumin has a wide spectrum of biological, pharmaceutical, and antioxidant effects in cancer experimental models. Nitrosamine is commonly used as an experimental oxidizing agent which induces gastric oxidative stress and gastric carcinogenesis in rats. We examined the antioxidant potential effect of curcumin against nitrosamine-induced gastric oxidative stress in rats. Forty Sprague-Dawley rats were randomly divided into 4 groups (10 rats/group). The control group was fed a standard diet and received a single dose of normal saline, the nitrosamine-treated group was fed a standard diet and received an intraperitoneal injection of nitrosamine at a single dose of 100 mg/kg body weight (b.w.). The other two groups received a daily dose of curcumin (200 mg/kg b.w.) via intra-gastric intubation in the presence or absence of nitrosamine injection. After 16 weeks, all rats were sacrificed, and the gastric tissues were dissected for histopathological examination and for biochemical measurements of oxidative stress indices. Our results showed that nitrosamine causes oxidative stress in gastric tissues as evidenced by glutathione depletion, increased level of lipid peroxides, nitric oxide release, impairment of total antioxidant capacity, DNA oxidative damage, and inhibition of antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, and superoxide dismutase). Histopathological findings revealed abnormal gastric architecture in association with nitrosamine injection compared to the non-treated control group. Curcumin significantly suppressed the gastric oxidative damage associated with nitrosamine treatment and mitigated its histopathological effect. These results suggest that curcumin, as an antioxidant, has a therapeutic effect against oxidative stress-mediated gastric diseases.