Native defect clustering-induced carrier localization centers leading to a reduction of performance in Ga0.70In0.30N/GaN quantum wells.

In this study, we aimed to better understand the mechanism for creating carrier localization centers (CLCs) in Ga0.70In0.30N/GaN quantum wells (QWs) and examine their impacts on device performance. Particularly, we focused on the incorporation of native defects into the QWs as a main cause of the mechanism behind the CLC creation. For this purpose, we prepared two GaInN-based LED samples with and without pre-trimethylindium (TMIn) flow-treated QWs. Here, the QWs were subjected to a pre-TMIn flow treatment to control the incorporation of defects/impurities in the QWs. In an effort to investigate how the pre-TMIn flow treatment affects the incorporation of native defects into the QWs, we employed steady-state photo-capacitance and photo-assisted capacitance-voltage measurements, and acquired high-resolution micro-charge-coupled device images. The experimental results showed that CLC creation in the QWs during growth is closely related to the native defects, most likely VN-related defects/complexes, since they have a strong affinity to In atoms and the nature of clustering. Moreover, the CLC creation is fatal to the performance of the yellow-red QWs since they simultaneously increase the non-radiative recombination rate, decrease the radiative recombination rate, and increase operating voltage-unlike blue QWs.

In vitro antidiabetic, antioxidant, antimicrobial, and cytotoxic activity of Murraya koenigii leaf extract intercedes ZnO nanoparticles.

Nanotechnology is an emerging field with tremendous potential and usage of medicinal plants and green preparation of nanoparticles (NPs) is one of the widely explored areas. These have been shown to be effective against different biological activities such as diabetes mellitus, cancer, antioxidant, antimicrobial, etc. The current studies focus on the green synthesis of zinc NPs (ZnO NPs) from aqueous leaf extract of Murraya koenigii (MK). The synthesized Murraya koeingii zinc oxide NPs (MK ZnO NPs) were characterized using UV-visible spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive spectrum (EDS) and cyclic voltammetry (CV). The synthesized MK ZnO NPs were evaluated for their in vitro antidiabetic, antioxidant, antimicrobial, and cytotoxic activity. They demonstrated significant antidiabetic and cytotoxic activity, as well as moderate free-radical scavenging and antibacterial activity.

Investigation and direct observation of sidewall leakage current of InGaN-Based green micro-light-emitting diodes.

Electrical and optical characteristics of InGaN-based green micro-light-emitting diodes (µLEDs) with different active areas are investigated; results are as follows. Reverse and forward leakage currents of µLED increase as emission area is reduced owing to the non-radiative recombination process at the sidewall defects; this is more prominent in smaller µLED because of larger surface-to-volume ratio. Leakage currents of µLEDs deteriorate the carrier injection to light-emitting quantum wells, thereby degrading their external quantum efficiency. Reverse leakage current originate primarily from sidewall edges of the smallest device. Therefore, aggressive suppression of sidewall defects of µLEDs is essential for low-power and downscaled µLEDs.

Metabolic labeling of glycans with isotopic glucose for quantitative glycomics in yeast.

Changes in glycan levels could directly affect the biochemical properties of glycoproteins and thus influence their physiological functions. In order to decode the correlation of glycan prevalence with their physiological contribution, many mass spectrometry (MS) and stable isotope labeling-based methods have been developed for the relative quantification of glycans. In this study, we expand the quantitative glycomic toolbox with the addition of optimized Metabolic Isotope Labeling of Polysaccharides with Isotopic Glucose (MILPIG) approach in baker's yeast (Saccharomyces cerevisiae). We demonstrate that culturing baker's yeast in the presence of carbon-13 labeled glucose (1-13C1) leads to effective incorporation of carbon-13 to both N-linked and O-linked glycans. We established that metabolic incorporation of isotope-labeled glucose at a concentration of 5 mg/mL for three days is required for an accurate quantitative analysis with optimal isotopic cluster distribution of glycans. To validate the robustness of the method, we performed the analysis by 1:1 mixing of normal and isotope-labeled glycans, and obtained excellent linear calibration curves from various analytes. Finally, we quantitated the inhibitory effect of tunicamycin, a N-linked glycosylation inhibitor, to glycan expression profile in yeast.

A pilot study of team-based primary health care for people with disabilities in South Korea.

To assess the feasibility of a primary health care (PHC) project for people with disabilities (PwDs) in South Korea, participants' experiences and perceptions were explored using the Analysis of Determinants of Policy Impact (ADEPT) model as a guide. Three focus group interviews and three one-on-one interviews were administered, and a directed content analysis was conducted based on four determinants from the ADEPT model. The findings showed that the project goal should be specified and reviewed periodically by participants. Although they were willing to devote themselves to the project, lack of a clear job description or mutual understanding often led to participants, especially health coordinators, feeling overwhelmed with their workload. Nevertheless, the project gave PwDs an opportunity to feel that they were being cared for by their care providers, while the participants as service providers had an opportunity to provide integrated care to their patients. For the successful settlement of team-based, person-centered PHC in South Korea, the formal PHC education should include an interprofessional team approach emphasizing communication skills among the health workforce. Opinions of PwDs and their family members also need to be reflected in the content of PHC.

Effects of an empowerment program for self-management among rural older adults with hypertension in South Korea.

OBJECTIVE: This study aimed to examine the effects of an empowerment program for hypertension self-management among rural older adults in South Korea. DESIGN: A pretest-posttest controlled design for a 12-month hypertension self-management program with assessments at commencement, 6 months and 12 months. SETTING: Two subsistence farming areas. PARTICIPANTS: Subsistence farmers aged 65 and over: intervention group (n = 41) and control group (n = 36). INTERVENTION: Twelve-month empowerment program for hypertension self-management. MAIN OUTCOME MEASURES: Self-efficacy, social support, self-care behaviours, blood pressure control and renal function. RESULTS: There were significant interactions of group by time for self-efficacy (P < 0.001) and self-care behaviour (P = 0.019). Blood pressure control at 12 months also showed a significant improvement in the empowered group compared with the control group (82.8% versus 56.8%, P < 0.014). Other clinical outcomes, including systolic blood pressure (P = 0.006) and renal function (P < 0.001), showed significant interactions of group by time. CONCLUSIONS: The empowerment program was effective for rural older adults with hypertension in South Korea. Further investigation of the relationships among core components of empowerment would be beneficial.

Porphyrin-POSS molecular hybrids.

Porphyrin-POSS hybrid: Porphyrin-POSS molecular hybrid composites (see scheme; POSS = polyhedral oligomeric silsesquioxanes) were synthesized and structurally characterized, allowing the realization of truly homogenous dispersion of basic functional building blocks between organic and inorganic components at the molecular level. These materials allow the optimization of aggregation/association behavior and thus the functional optical properties of the porphyrinato zinc compounds.

Photoluminescence properties of NaSr(P, V)O4:Eu3+ phosphors.

Eu3+ activated NaSr(P,V)O4 phosphors have been synthesized using solid state reaction method and further characterized for their structure and optical properties using different techniques such as X-ray diffraction, scanning electron microscopy, photolumniscenec excitation, emission, and chromaticity coorrdinate analysis, etc. Material shows a broad excitation peak (monitored for lambda(ems) = 613 nm) lying in the 300-360 nm region and gives intense transitions (lambda(exc) = 320 nm) namely 5D0 --> 7F1 at 590 nm, 5D0 --> 7F2 at 613 nm, 5D0 --> 7F3 at 650 nm, and 5D0 --> 7F4 at 700 nm due to Eu3+ ion. Our results show that replacement of the PO4(3-) ions with isomorphic VO4(3-) ions improves the structural stability and the overall intensity of the emission. The maxium emission intensity is achieved for the NaSr(P0.4, V0.6)O4:Eu3+ phosphor. An estimated increase of an order is attained for the NaSr(P0.4, V0.6)O4:Eu3+ phosphor as compared to NaSrPO4:Eu3+ or NaSrVO4:Eu3+ phosphor. The chromaticity coordinate of the phosphor (0.68, 0.31) lies well within the red region and suggest that the material could be an alternative red phosphor for lighting and display applications.

Enhancement in the microstructure and photoluminescence properties of YVO4:Eu3+ by Al doping.

Al contents have been doped as a sensitizer to improve the luminescent brightness, and the conventional solid state reaction method has been used to synthesize the phosphors. Al doping effects on the microstructures of YVO4:Eu3+ phosphors were measured by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The luminescent characteristics were characterized by photoluminescence excitation (PLE) and emission (PL) measurements. Incorporation of Al3+ ions into the YVO4:Eu phosphors has greatly enhanced the crystallinity, particle size and hence the luminescence properties and the optimum concentration in Al dopants are found to be 0.05 mol. The photoluminescence intensity of 0.05 mol Al(3+)-doped YVO4:Eu3+ phosphors was improved by a factor of 1.41, in comparison with undoped Y0.95Eu0.05VO4 phosphor. The improvement in photoluminescence properties with Al doping may result from the improved crystallinity and from the enlarged grain sizes inducing lower scattering loss.

Optical characterization of Eu3+ doped ZnO nanocomposites.

A rare-earth metal ion (Eu3+) doped ZnO nanocomposites have been successfully synthesized by employing wet chemical procedure using multi-wall carbon nanotubes (MWCNT's) as removable template. The preparation was carried out by immersing empty and dried MWCNT's in a stoichiometric composition of zinc nitrate and europium nitrate solution followed by filtration and sintering. The synthesized Eu3+ doped ZnO nanocomposites were characterized by means of different characterization techniques namely XRD, SEM, EDS, FT-IR and Raman spectroscopy. The XRD profile of the Eu3+ doped ZnO nanocomposites indicated its hexagonal nature while the photoluminescent analysis reveals that the prepared nanocomposite exhibits a strong red emission peak at 619 nm due to 5D0 --> 7F2 forced electric dipole transition of Eu3+ ions. Such luminescent materials are expected to find potential applications in display devices.

Psychometric evaluation of a Korean version of the 8-item Medication Adherence Scale in rural older adults with hypertension.

OBJECTIVE: To examine the psychometric properties of a structured self-reported 8-item Korean-version Morisky Medication Adherence Scale (MMAS-K) among rural older adults with hypertension. DESIGN: Cross-sectional descriptive survey. SETTING: A rural community comprising three primary health care posts in Gangwon Province, South Korea. PARTICIPANTS: Ninety-two older adults with hypertension who received treatment at primary health care posts. MAIN OUTCOME MEASURES: Participants completed an 8-item MMAS-K questionnaire, and the community health practitioners manually measured blood pressure. Factor analysis and correlation coefficient for validity and the Kuder-Richardson alpha coefficient for reliability of the MMAS-K were used, while the association between medication adherence and blood pressure control was determined using Fisher's exact test. RESULTS: Internal consistency reliability was acceptable with a coefficient alpha of 0.71. The factor analysis of construct validity identified two dimensions of the 8-item MMAS-K, explaining 52.22% of the total variance. There was a high correlation between the 8-item MMAS-K and the original 4-item MMAS (r = 0.874), indicating that these scales measure theoretically related constructs for convergent validity. There was a significant association between the 8-item MMAS-K score and blood pressure control (P < 0.05), indicating that, for the known-groups validity, the controlled blood pressure group was more likely to have higher rate of medication adherence than the poor-control group. CONCLUSIONS: The findings indicate a positive association between medication adherence and blood pressure control. The 8-item MMAS-K possesses adequate validity and reliability among rural older adults with hypertension.

Benzimidazole bearing oxadiazole and triazolo-thiadiazoles nucleus: design and synthesis as anticancer agents.

Two new series of benzimidazole bearing oxadiazole[1-(1H-benzo[d]imidazol-2-yl)-3-(5-substituted-1,3,4-oxadiazol-2-yl)propan-1-ones (4a-l)] and triazolo-thiadiazoles[1-(1H-benzo[d]imidazol-2-yl)-3-(6-(substituted)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-3-yl)propan-1-one (7a-e)] have been synthesized successfully from 4-(1H-benzo[d]imidazol-2-yl)-4-oxobutanehydrazide (3) with an aim to produce promising anticancer agents. In vitro anticancer activities of synthesized compounds were screened at the National Cancer Institute (NCI), USA, according to their applied protocol against full NCI 60 human cell lines panel; results showed good to remarkable anticancer activity. Among them, compound (4j, NCS: 761980) exhibited significant growth inhibition and further screened at 10-fold dilutions of five different concentrations (0.01, 0.1, 1, 10 and 100 µM) with GI(50) values ranging from 0.49 to 48.0 µM and found superior for the non-small cell lung cancer cell lines like HOP-92 (GI(50) 0.49, TGI 19.9,LC(50) >100 and Log(10)GI(50) -6.30, Log(10)TGI -4.70, Log(10)LC(50) >-4.00).

Liquid chromatography-tandem mass spectrometry for quantification of lacosamide, an antiepileptic drug, in rat plasma and its application to pharmacokinetic study.

A rapid, simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) was developed for the determination of an antiepileptic drug, lacosamide, in rat plasma. The method involves the addition of acetonitrile and internal standard solution to plasma samples, followed by centrifugation. An aliquot of the supernatant was diluted with water and directly injected into the LC/MS/MS system. The separations were performed on column packed with octadecylsilica (5 µm, 2.0 × 50 mm) with 0.1% formic acid and acetonitrile as mobile phase, and the detection was performed on tandem mass spectrometry by the multiple-reaction monitoring via an electrospray ionization source. The standard curve was linear over the concentration range from 0.3 to 1000 ng/mL. The lower limit of quantification was 0.3 ng/mL using 50 µL of rat plasma sample. The intra- and inter-assay precision and accuracy were found to be less than 11.7 and 8.8%, respectively. The developed analytical method was successfully applied to the pharmacokinetic study of lacosamide in rats.

[Job Analysis of Nurse Care Coordinators for Chronic Illness Management in Primary Care Settings: Using Developing a Curriculum Process].

PURPOSE: This study aimed to conduct a job analysis of nurse carecoordinators and to identify the frequency, importance and difficulty of each task of their job. METHODS: A committee for developing a curriculum (DACUM) was formed and members of the committee defined nurse care coordinators' jobs and enumerated the duties, tasks and task elements by applying the DACUM technique. Then nurse care coordinators enrolled in the pilot project evaluated the frequency, importance and difficulty of each task. RESULTS: From the job descriptions of nurse care coordinators, we identified 12 duties and 42 tasks. Each task comprised 1~5 task elements. Among tasks, 'assess the patient's general health status' was carried out most frequently. Nurse care coordinators perceived that 'check vital signs' and'strengthen patient competence to promote health behaviors' were more important than all other tasks. The most difficult task was 'develop professionalism as a nurse care coordinator'. CONCLUSION: The nurse care coordinators' roles developed in this study will serve as the key guidelines for human resource management of care coordinators. Further, job specifications for nurse care coordinators need to be developed, which is necessary for designing education and training programs. We also need to integrate primary health care as an essential component in nursing education.

Optimal screening cut-off points for renal impairment in rural Korean older adults taking medications.

The purpose of this descriptive, cross-sectional study was to identify the optimal cut-off point of estimated glomerular filtration rate (eGFR) using the area under the receiver operating characteristic curve to screen for renal impairment among rural Korean older adults taking medications (N = 100). Renal function was assessed by eGFR using the Cockcroft-Gault formula. Nearly half of participants took five or more prescription drugs, and 46% took nephrotoxic medications. Participants' optimal eGFR cut-off points in screening for renal impairment with and without polypharmacy were 54.3 mL/min (area under curve [AUC] = 0.824, p < 0.001) and 61.4 mL/min (AUC = 0.768, p < 0.001), respectively. The incidence of renal impairment was 61.2% and 56.9%, respectively, using 54.3 mL/min and 61.4 mL/min as the new optimal cut-offs of eGFR with and without polypharmacy. More than half of the rural older adults require a reduction in medication dosage or a change to non-nephrotoxic medications. These new optimal cut-off points using eGFR according to polypharmacy may be helpful in screening for renal impairment among rural older adults taking medications.

Understanding Facilitators and Barriers of Online Cancer Information Utilization among Cancer Survivors and their Families: Focus on the Theory of Planned Behavior.

OBJECTIVE: Cancer survivors have various health care needs and are willing to be proactive with their health maintenance. Online information would be a useful resource to guide cancer survivors and their family members. Therefore, identifying the factors that influence Internet searching behaviors among cancer survivors and their family members is a first step toward providing better health care services for cancer care. METHODS: We performed focus group interviews that were based on the Theory of Planned Behavior, with thirty-one participants to explore factors related to Internet search behaviors among cancer survivors and their family members. RESULTS: Six themes were identified in the analysis of participant interviews. Attitudes toward searching for health information on the Internet included the themes "Fulfilling unmet needs" and "Confirmation through second opinion." Themes related to social norms included "a required step for sure" and "helping each other." In terms of perceived behavioral control, themes included "difficult to choose because of being 'overwhelmed with information,'" and "complex searching milieu." CONCLUSION: It was clear that cancer survivors and their family members had unmet needs for maintaining their health status. They wanted to be informed and actively involved in the decision-making process regarding health management. Consultation and education provided to patients by doctors should not only include information on diet and nutrition but also information on the resulting complications to satisfy their need for reliable health information.

Identifying the cause of thermal droop in GaInN-based LEDs by carrier- and thermo-dynamics analysis.

This study aims to elucidate the carrier dynamics behind thermal droop in GaInN-based blue light-emitting diodes (LEDs) by separating multiple physical factors. To this end, first, we study the differential carrier lifetimes (DCLs) by measuring the impedance of a sample LED under given driving-current conditions over a very wide operating temperature range of 300 K-500 K. The measured DCLs are decoupled into radiative carrier lifetime (τR) and nonradiative carrier lifetime (τNR), via utilization of the experimental DCL data, and then very carefully investigated as a function of driving current over a wide range of operating temperatures. Next, to understand the measurement results of temperature-dependent τR and τNR characteristics, thermodynamic analysis is conducted, which enables to look deeply into the temperature-dependent behavior of the carriers. On the basis of the results, we reveal that thermal droop is originated by the complex dynamics of multiple closely interrelated physical factors instead of a single physical factor. In particular, we discuss the inherent cause of accelerated thermal droop with elevated temperature.

Anger as a predictor of suicidal ideation in middle-school students in Korea: gender difference in threshold point.

Studies on gender differences in suicidal ideation and anger are limited. Furthermore, these studies focused on linear relationships, which limits the full understanding of the complex relationships and hampers identification of high-risk groups for suicidal tendencies. Hence, this study aims to assess the gender differences in: (1) the level of suicidal ideation and anger; (2) predictors for suicidal ideation; and (3) the varying association between suicidal ideation and anger. The target population for this cross-sectional, correlational study was adolescents aged 13 to 15 years living in South Korea. A total of 258 adolescents (160 boys and 98 girls) completed the Multidimensional Anger Inventory and Suicidal Ideation Questionnaire. Data were analyzed by descriptive statistics, multiple linear, and spline regression analysis. Girls reported significantly higher scores in both anger and suicidal ideation. While anger was a significant predictor for suicidal ideation only in boys, both school life satisfaction and anger were significant predictors of suicidal ideation in girls. After controlling for sociodemographic factors, the spline regression revealed a significant threshold point in the relationship between anger and suicidal ideation, particularly among girls. At the threshold anger point of 117.67, 12.5% of girls belonged to the high-risk group. The gender-specific patterns of the relationship between suicidal ideation and anger and the existence of threshold points confirmed the need for targeted suicidal preventive programs focusing on controlling anger.

Synthesis and preliminary biological evaluation of novel pyrazolo[1,5-a]pyrazin-4(5H)-one derivatives as potential agents against A549 lung cancer cells.

A series of novel pyrazolo[1,5-a]pyrazin-4(5H)-one derivatives were synthesized by the reaction of ethyl 3-aryl-1-(2-bromoethyl)-1H-pyrazole-5-carboxylate and amine in the general heating condition and microwave-assisted condition. The structures of the compounds were determined by IR, (1)H NMR and mass spectroscopy, in addition, representative single-crystal structures were characterized by using X-ray diffraction analysis. Preliminary biological evaluation showed that the compounds could inhibit the growth of A549 cells in dosage- and time-dependent manners. The study on structure-activity relationships showed that compounds with 4-chlorophenyl group at pyrazole moiety, such as 5-benzyl-2-(4-chlorophenyl)-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one (3o) had much more inhibitory effects. Compound 3o was the most effective small molecule in inhibiting A549 cell growth and might perform its action through modulating autophagy.

5-Alkyl-2-ferrocenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one derivatives inhibit growth of lung cancer A549 cell by inducing apoptosis.

we found that 5-alkyl-2-ferrocenyl-6,7-dihydropyrazolo[1,5-a]pyrazin-4(5H)-one derivatives 8d, 8e and 8f could effectively induce apoptosis in A549 lung cancer cells and elevate the levels of integrin beta4 and ROS. The data suggested that these compounds might be promising agents for the cancer therapy, and these compounds would be useful tools for further investigate the functions of integrin beta4 in regulation of the cancer cell apoptosis.