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.

[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.

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.

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.

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.

How Much Do Older Adults Living Alone in Rural South Korea Know About Dementia?

OBJECTIVES: This study aimed to examine the level of dementia knowledge of older Korean adults living alone in rural areas and to identify related factors. METHODS: A cross-sectional descriptive design was applied. The participants were 231 older adults living alone who were recruited from 12 of the 13 primary health care posts in the rural area of Chuncheon. Participants' level of dementia knowledge was assessed using the Dementia Knowledge Scale. Data were analyzed using descriptive statistics, and the t-test, analysis of variance, chi-square test, and Mann-Whitney test were applied. RESULTS: Participants' mean age was 77.3±5.4 years, and women comprised 79.7% of the sample. Over half of the participants (61.9%) had no formal education, and all the participants were enrolled in Medical Aid. The participants' average percentage of correct answers was 61.6%. The highest rate (94.4%) was for the item "Dementia can change one's personal character." The item with the lowest proportion of correct answers was "Dementia is not treatable" (23.4%). Dementia knowledge was significantly associated with age, education, health coverage, source of living expenses, and dementia risk. CONCLUSIONS: Dementia knowledge among Korean rural older adults living alone was relatively low. Participants' misconceptions about symptoms and treatment could hinder them from seeking early treatment. The results of this study suggest the need for active outreach and health care delivery for rural older adults living alone in South Korea.

One-year mortality among newly admitted older patients in a long-term care hospital in South Korea.

OBJECTIVES: Older Korean people's admission to long-term care (LTC) hospitals is increasing. This study aimed to investigate one-year mortality and related factors among older patients admitted to a LTC hospital. METHODS: Medical records of 330 patients admitted to a LTC hospital in 2014 were reviewed. Factors related to death were identified using the Cox proportional hazards model. RESULTS: About 35% of the patients died within a year, and their average length of survival was 42.3 (SD = 68.4) days. Predictors of mortality within one year were as follows: cancer (hazard ratio (HR) = 3.04); aged 85 and older (HR = 2.61); dependency: K-ADL ≥ 21 (HR = 2.14); male sex (HR = 1.95); respiratory disease (HR = 1.68); cognitive function (HR = 1.65); and abnormal serum sodium level (HR = 1.65). CONCLUSION: At admission, proper assessment and planning for older patients at risk are beneficial to minimise negative consequences. The roles of LTC hospitals need further discussion.

Optoelectronic Performance Variations in InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes: Effects of Potential Fluctuation.

We investigate the cause of the optoelectronic performance variations in InGaN/GaN multiple-quantum-well blue light-emitting diodes, using three different samples from an identical wafer grown on a c-plane sapphire substrate. Various macroscopic measurements have been conducted, revealing that with increasing strain in the quantum wells (QWs), the crystal quality improves with an increasing peak internal quantum efficiency while the droop becomes more severe. We propose to explain these variations using a model where the in-plane local potential fluctuation in QWs is considered. Our work is contrasted with prior works in that macroscopic measurements are utilized to find clues on the microscopic changes and their impacts on the device performances, which has been rarely attempted.

Factors associated with mortality risk in critical care patients treated with veno-arterial extracorporeal membrane oxygenation.

OBJECTIVES: To identify factors associated with mortality in patients treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and to validate the discrimination of the risk assessment tools to predict mortality. BACKGROUND: VA-ECMO is a rescue therapy for patients with life-threatening cardiac failure, but mortality remains high. METHODS: In this retrospective study, we reviewed the medical records of adult patients who underwent VA-ECMO in an intensive care unit of a university hospital, between 2009 and 2013. RESULTS: VA-ECMO was performed in 89 patients, with a median duration of 116 h. The survival rate until hospital discharge was 27%. The pre-ECMO simplified acute physiology score (SAPS) II and diabetes mellitus were significant predictors of hospital mortality. The optimal prognostic SAPS II score was 81 overall, 80 in patients with diabetes, and 84 in those without diabetes. CONCLUSIONS: Our findings indicate that high pre-ECMO SAPS II score and diabetes are risk factors for mortality in patients who undergo VA-ECMO.

Designing an Internet-Based Intervention Tailored to Psychological Factors for CVD Risk Reduction: Role of Stress and Anger.

PURPOSE: To examine the mediating role of occupational stress on the relationship of anger expression to cardiovascular disease (CVD) risk using Framingham risk score equation in Korean adults with metabolic syndrome. METHODS: This cross-sectional study was a secondary analysis of baseline data from a longitudinal study conducted in 91 Korean male workers. Psychological variables were assessed using structured questionnaires. RESULTS: Occupational stress was significantly predictive of CVD risk (ß=.278, p=.008). The inclusion of occupational stress non-significantly decreased the standardized beta by 33.6% for anger expression as a predictor of CVD risk (ß=.152, p=.163). The Sobel test showed a significant mediating effect between occupational stress and CVD risk (p<0.01). CONCLUSION: This mediating role of occupational stress has important clinical implications as interventions designed to manage anger expression to reduce CVD risk in this population.

Study on the biodegradation of perfluorooctanesulfonate (PFOS) and PFOS alternatives.

OBJECTIVES: In this study, we investigated the biodegradation features of 4 perfluorooctanesulfonate (PFOS) alternatives developed at Changwon National University compared to those of PFOS. METHODS: Biodegradation testing was performed with microorganisms cultured in the good laboratory practice laboratory of the Korea Environment Corporation for 28 days following the Organization for Economic Cooperation and Development guidelines for the testing of chemicals (Test No. 301 C). RESULTS: While C8F17SO3Na, PFOS sodium salt was not degraded after 28 days, the 4 alternatives were biodegraded at the rates of 20.9% for C15F9H21S2O8Na2, 8.4% for C17F9H 25S2O8Na2, 22.6% for C23F18H28S2O8Na2, and 23.6% for C25F17H32O13S3Na3. CONCLUSIONS: C25F17H32S3O13Na3, C23F18H28S2O8Na2, and C15F9H21S2O8Na2 were superior to PFOS in terms of biodegradation rates and surface tension, and thus they were considered highly applicable as PFOS alternatives. Environmental toxicity, human toxicity, and economic feasibility of these compounds should be investigated prior to their commercialization.

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.

Direct synthesis of pyrazoles from esters using tert-butoxide-assisted C-(C=O) coupling.

This paper describes the direct synthesis of pyrazoles from esters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield ß-ketonitrile or α,ß-alkynone intermediates, and condensation by hydrazine addition. The method reported allows for easy control of the regioselectivity and structure of substituents at N-1, C-3, C-4 and/or C-5 positions.

Older adults' perception of chronic illness management in South Korea.

OBJECTIVES: Despite the recent emphasis on a patient-centered chronic care model, few studies have investigated its use in older adults in South Korea. We explored how older Korean adults perceive and cope with their chronic illness. METHODS: We conducted focus group interviews in Seoul, Korea in January 2010. Focus groups were formed by disease type (hypertension and type 2 diabetes) and gender using purposive sampling. Inclusion criteria were patients aged 60 and over who had been diagnosed with diabetes or hypertension and received care at a community health center for at least six months prior to participation. Interview data were analyzed through descriptive content analysis. RESULTS: Among personal factors, most participants felt overwhelmed when they received their diagnosis. However, with time and control of their acute symptoms using medication, their worry diminished and participants tended to denying being identified as a patient or sick person. Among socio-familial factors, participants reported experiencing stigma with their chronic illness and feeling it was a symbol of weakness. Instead of modifying their lifestyles, which might interfere with their social relationships, they resorted to only following their medicine regime prescribed by their doctor. Participants also reported feeling that their doctor only prescribed medications and acted in an authoritative and threatening manner to induce and reinforce participants' compliance with treatment. CONCLUSIONS: For successful patient-centered management of chronic illnesses, supportive environments that include family, friends, and healthcare providers should be established. OBJECTIVES: Despite the recent emphasis on a patient-centered chronic care model, few studies have investigated its use in older adults in South Korea. We explored how older Korean adults perceive and cope with their chronic illness. METHODS: We conducted focus group interviews in Seoul, Korea in January 2010. Focus groups were formed by disease type (hypertension and type 2 diabetes) and gender using purposive sampling. Inclusion criteria were patients aged 60 and over who had been diagnosed with diabetes or hypertension and received care at a community health center for at least six months prior to participation. Interview data were analyzed through descriptive content analysis. RESULTS: Among personal factors, most participants felt overwhelmed when they received their diagnosis. However, with time and control of their acute symptoms using medication, their worry diminished and participants tended to denying being identified as a patient or sick person. Among socio-familial factors, participants reported experiencing stigma with their chronic illness and feeling it was a symbol of weakness. Instead of modifying their lifestyles, which might interfere with their social relationships, they resorted to only following their medicine regime prescribed by their doctor. Participants also reported feeling that their doctor only prescribed medications and acted in an authoritative and threatening manner to induce and reinforce participants' compliance with treatment. CONCLUSIONS: For successful patient-centered management of chronic illnesses, supportive environments that include family, friends, and healthcare providers should be established.

Spatiotemporal path discontinuities of wavepackets propagating across a meta-atom.

The realization of phase discontinuities across metasurfaces has led to a new class of reflection and refraction. Here we present theory and experiment on the discontinuous propagation of wavepackets across subwavelength-thickness meta-atoms. Using acoustic waves, we observe the process of wavepackets traversing a meta-atom with abrupt displacements, which appear as path discontinuities on a space-time diagram. We construct a tunable meta-atom from two coupled resonators at ~500 Hz, map the spatiotemporal trajectories of individual sonic pulses, and reveal discontinuities at the meta-atom where the pulses exit at a time ~50 ms ahead or behind their arrivals. Applications include thin acoustic metasurface lenses.

Luminescence and thermal-quenching properties of Dy³âº-doped Ba2CaWO6 phosphors.

A series of new double perovskite tungstate Ba2CaWO6:xDy(3+) (0.01⩽x⩽0.15) phosphors were synthesized via solid state reaction process. XRD analysis confirmed the phase formation of Ba2CaWO6:Dy(3+) materials. The photoluminescence excitation and emission spectra, concentration effect, thermal-quenching, and decay property were investigated. The phosphor could be excited by the UV light region from 250 to 400 nm, and it exhibits blue (493 nm) and yellow (584 nm) emission corresponding to (4)F(9/2)-(6)H(15/2) transitions and (4)F9/2-(6)H13/2 transitions, respectively. The optimum dopant concentration of Dy(3+) ions in Ba2CaWO6:xDy(3+) is around 5 mol% and the critical transfer distance of Dy(3+) is calculated as 14 Å. The thermal-quenching temperature is 436 K for Ba2CaWO6:0.05Dy(3+). The fluorescence lifetime is also determined in Ba2CaWO6:0.05Dy(3+).

Biodegradation of perfluorooctanesulfonate (PFOS) as an emerging contaminant.

Perfluorooctanesulfonate (PFOS) is a compound of global concern because of its persistence and bioaccumulation in the environment. Nevertheless, little is known of the potential for PFOS biodegradation, even though the importance of characterizing the function and activity of microbial populations detected in the environment has been discussed. This study focused on the biodegradation of PFOS by a specific microorganism. Through this study, we have identified the aerobic microorganism for the specific decomposition of PFOS from wastewater treatment sludge, as a well-known sink for environmental PFOS. This species was Pseudomonas aeruginosa strain HJ4 with a 99% similarity, a mesophilic rod type bacteria (30-37°C). A pH range of 7-9 was determined to be optimal for the growth of strain HJ4. In this study approximately 67% over a range of concentrations (1400-1800µgL(-)(1)) for PFOS was biologically decomposed by P. aeruginosa after 48h incubation. This result is reported here for the first time, which strongly pertains to the efficient biodegradation of PFOS. Therefore, our study is considered a major advancement in sustainable PFOS treatment.