Revisiting the basis of the excited states for solvated fluorinated benzenes and pentafluorophenylalanine.

Vapor-phase molecular simulation studies of aromatic compounds with five or more fluorine atoms on the ring reveal emission spectra characterized by S0 → πσ* and πσ*→S0 transitions. In this study, the absorption, excitation, and solvent-dependent emission spectra of fluorinated benzenes, including pentaflurophenyalanine (F5Phe), which is a potential marker for biochemical research, were collected and compared to the results of the simulation. Time-dependent self-consistent field (TD-SCF) density functional theory (DFT) calculations were performed to examine the nature of excited states and relevant photo-physical processes. The results show that pentafluorobenzene (PFB) and hexafluorobenzene (HFB) show behavior consistent with the vapor phase simulation studies, that tracts well with benzenes substituted with fewer fluorine atoms. For example, 1,2,3-trifluorobenzene (123TFB) and 1,2,3,4-tetrafluorobenzene (1234TFB) show emission spectra with varying intensities of tails and shoulders. Those features are attributed to πσ*→S0 transitions where the πσ* state has been stabilized in the presence of solvents like water, acetonitrile, and isopropanol, which are different from their simulated behavior in the gas phase. The emission in water solvent especially shows a significant increase in the emission intensity at 310 nm, which is common for all studied samples. The emission spectrum of F5Phe closely reflects that of PFB, which arises from the interplay of both ππ *→S0 and πσ*→S0 transitions. Also, it is observed that the interaction between adjacent σ* orbitals of C-F bond for 123-TFB, 1234-TFB, 12345-PFB, and 123456-HFB contributes to further narrowing the energy gap between S0 and S1 states with a significant red shift on the emission spectra compared to their isomers.

Short- and Long-Term Structural Characterization of Cured-in-Place Pipe Liner with Reinforced Glass Fiber Material.

Cured-in-place pipe (CIPP), as a kind of trenchless sewer rehabilitation technology, is a method to repair sewer pipe using unsaturated polyester resin. This study develops a CIPP liner using hot water or steam curing as well as glass fiber, in contrast to traditional methods, which use nonwoven fabric. Composite material samples were fabricated by combining liner materials using various methods, and the structural characteristics of the liners were compared and analyzed through short- and long-term flexural strength tests. A long-term test was conducted for 10,000 h, and the results revealed 13.3 times higher flexural strength and 8 times higher flexural modulus than the American Society for Testing Materials minimum criteria for CIPP short-term properties. The maximum creep retention factor was 0.64, thereby reducing the design thickness of the CIPP by up to 54%. The structural characteristics also improved when glass fibers were mixed with traditional CIPP liner, making it possible to reduce the thickness by 30%. Glass fibers result in high structural strength when combined with unsaturated polyester resin. Structural strength increased, even when glass fibers were mixed with traditional CIPP liner. The main contribution of this research is the development of a high strength CIPP liner and improvement of the structural properties of CIPP lining without using the specially formulated resin or lining materials.

Removal of Hydrogen Sulfide in Septic Tanks for Treating Black Water via an Immobilized Media of Sulfur-Oxidizing Bacteria.

In South Korea, the installation of septic tanks for treating black water (STBW) is regulated even in sewage treatment areas to prevent the black water deposition in combined sewers. STBWs in which black water is anaerobically decomposed generate high concentrations of hydrogen sulfide (H2S). In this study, an immobilized media of sulfur-oxidizing bacteria (SOB) was used to remove the H2S. SOB media was prepared by using activated sludge collected from a wastewater treatment plant. Prior to field application, an appropriate cultivation period and aeration rate for SOB activation were estimated through a laboratory-scale test. The SOB was activated after a 23-day cultivation period and an aeration rate of 0.25 L-water/L-air/min. Moreover, the maximum H2S removal efficiency was observed at a cultivation period of 43 days and an aeration rate of 0.38 L-water/L-air/min. Then, the SOB media was installed on STBWs of various capacities. The H2S removal efficiency was compared between with and without SOB media. The maximum H2S elimination capacity with SOB media was 12.3 g/m3/h, which was approximately three times higher than without SOB media. Furthermore, the energy efficiency and oxidation rate were also three times higher with SOB, demonstrating the applicability of SOB for H2S removal in STBW.

Effects of pH on the simultaneous removal of hydrogen sulfide and ammonia in a combined absorption and electro-oxidation system.

Biogas commonly contains both H2S and NH3, and these impurities need to be removed before use. In this study, a combined system consisting of an absorption column and an electro-oxidation reactor was developed to simultaneously treat H2S and NH3. In particular, the effect of the pH (6, 8, and 10) on the system performance was investigated. The mass transfer rate of H2S from the gas to liquid phases was sensitive to pH because of its relatively low solubility at low pHs, while more than 99% of the introduced NH3 was steadily absorbed. Therefore, a pH higher than 8 was favorable for the simultaneous removal of both gases. In the electro-oxidation reactor, H2S was primarily oxidized, while the NH3 oxidation started after H2S was completely eliminated. Furthermore, the oxidation rate and current efficiency of both H2S and NH3 increased with decreasing pH value. The results showed that a low pH was advantageous for the electro-oxidation. In conclusion, the mass transfer rate and oxidation kinetics should be balanced to increase the simultaneous removal of H2S and NH3. Therefore, among the tested pH values, the best performance in the combined system was achieved using a pH of 8.

Simultaneous removal of hydrogen sulfide and ammonia using a combined system with absorption and electrochemical oxidation.

Hydrogen sulfide (H2S) and ammonia (NH3), common impurities in biogas, need to be removed before utilizing it. In this study, a combined system, which consisted of an absorption column and an electrochemical oxidation reactor, was tested to simultaneously remove these impurities. The effects of the current density and the chemical loading rate on the system performance were investigated. Firstly, the mass transfer coefficients for the absorption column were determined at various gas flow rates. More mass of NH3 was transferred, compared with that of H2S, because of its higher solubility. In the electro-oxidation reactor, reactive chlorine species (RCSs) were generated and oxidized both H2S and NH3; however, NH3 started to degrade only after H2S was completely eliminated. At a current density of 400 A/m2, the current efficiencies of H2S and NH3 were 23.1% and 5.9%, respectively. In the combined system, the removal efficiency of H2S was closely related to the mass ratio of the H2S transferred and the RCSs generated. The removal efficiency of H2S was greater than 99% when the ratio was less than 1. The mass transfer potential and the oxidation kinetics should be balanced to improve the system performance for the simultaneous removal of H2S and NH3.

Relationship Between Catastrophic Health Expenditures and Income Quintile Decline.

OBJECTIVES: The aims of this study were to investigate the proportion of households facing catastrophic health expenditures based on household income quintiles, and to analyze the relationship between expenditures and household income quintile decline. METHODS: Study data were obtained from an annually conducted survey of the 2012-2013 Korean health panel. There were 12,909 subjects aged 20-64 years from economically active households, whose income quintile remained unchanged or declined by more than one quintile from 2012 to 2013. Logistic regression analysis was performed to determine whether catastrophic health expenditures in 2012 were related to more than one quintile income decline in 2013. RESULTS: Households facing catastrophic health expenditures of ≥ 40%, ≥ 30%, and ≥ 10% of a household's capacity to pay, were 1.58 times (p < 0.003), 1.75 times (p < 0.000), and 1.23 times (p < 0.001) more likely to face a decline in income quintile, respectively. CONCLUSION: Over a 1 year period, the proportion of households facing more than one quintile income decline was 16.4%, while 2.1% to 2.5% of households in Korea faced catastrophic health expenditures. Catastrophic health expenditure experienced in 2012 was significantly associated with income quintile decline 1 year later. Therefore, lowering the proportion of households with catastrophic health expenditure may reduce the proportion of households with income quintiles decline.

Nurse-Perceived Patient Adverse Events depend on Nursing Workload.

OBJECTIVES: The purpose of this study was to investigate the correlation between nursing workload and nurse-perceived patient adverse events. METHODS: A total of 1,816 nurses working in general inpatient units of 23 tertiary general hospitals in South Korea were surveyed, and collected data were analyzed through multilevel logistic regression analysis. RESULTS: Among variables related to nursing workload, the non-nursing task experience had an influence on all four types of patient adverse events. Nurses with non-nursing tasks experienced patient adverse events-falls [odds ratio (OR) = 1.31], nosocomial infections (OR = 1.23), pressure sores (OR = 1.16), and medication errors (OR = 1.23)-more often than occasionally. In addition, when the bed to nurse ratio was higher, nurses experienced cases of pressure sores more often (OR = 1.35). By contrast, nurses who said the nursing workforce is sufficient were less likely than others to experience cases of pressure sores (OR = 0.78). Hospitals with a relatively high proportion of nurses who perceived the nursing workforce to be sufficient showed a low rate of medication error (OR = 0.28). CONCLUSION: The study suggested that the high level of nursing workload in South Korea increases the possibility of patient adverse events.

Dental Care Utilization for Examination and Regional Deprivation.

OBJECTIVES: Receiving proper dental care plays a significant role in maintaining good oral health. We investigated the relationship between regional deprivation and dental care utilization. METHODS: Multilevel logistic regression was used to identify the relationship between the regional deprivation level and dental care utilization purpose, adjusting for individual-level variables, in adults aged 19+ in the 2008 Korean Community Health Survey (n=220 258). RESULTS: Among Korean adults, 12.8% used dental care to undergo examination and 21.0% visited a dentist for other reasons. In the final model, regional deprivation level was associated with significant variations in dental care utilization for examination (p<0.001). However, this relationship was not shown with dental care utilization for other reasons in the final model. CONCLUSIONS: This study's findings suggest that policy interventions should be considered to reduce regional variations in rates of dental care utilization for examination.

Unmet healthcare needs depending on employment status.

OBJECTIVES: The purpose of study is to find relevance between unmet healthcare needs and employment status and if factors have relevance to unmet healthcare needs due to "economic burden" and "no time to spare". METHODS: The study conducted a survey of 9163 respondents who said they needed a medical treatment or checkup were asked why the need for care was unmet. RESULTS: 22.9% of the respondents said they did not receive a medical treatment or checkup they needed at least once. The rate of unmet healthcare needs caused by "economic burden" was higher among temporary workers (ORs=2.13), day workers (ORs=1.92). However, the rate of unmet needs due to "no time to spare" was lower for temporary workers (ORs=.58) than for regular workers, studies (ORs=.33), housework (ORs=.26), early retirement (ORs=.19) and disease or injury (ORs=.07). CONCLUSION: Non-regular waged workers were more likely to have an unmet need for healthcare due to "economic burden" than regular waged workers. On the other hand, regular waged workers were less likely to receive necessary healthcare services due to "no time to spare" than non-regular waged workers and economically inactive people.

Influence of the nursing practice environment on job satisfaction and turnover intention.

OBJECTIVES: To examine whether the nursing practice environment at the hospital-level affects the job satisfaction and turnover intention of hospital nurses. METHODS: Among the 11 731 nurses who participated in the Korea Health and Medical Workers' Union's educational program, 5654 responded to our survey. Data from 3096 nurses working in 185 general inpatient wards at 60 hospitals were analyzed using multilevel logistic regression modeling. RESULTS: Having a standardized nursing process (odds ratio [OR], 4.21; p<0.001), adequate nurse staffing (OR, 4.21; p<0.01), and good doctor-nurse relationship (OR, 4.15; p<0.01), which are hospital-level variables based on the Korean General Inpatients Unit Nursing Work Index (KGU-NWI), were significantly related to nurses' job satisfaction. However, no hospital-level variable from the KGU-NWI was significantly related to nurses' turnover intention. CONCLUSIONS: Favorable nursing practice environments are associated with job satisfaction among nurses. In particular, having a standardized nursing process, adequate nurse staffing, and good doctor-nurse relationship were found to positively influence nurses' job satisfaction. However, the nursing practice environment was not related to nurses' turnover intention.

Nurse-perceived patient adverse events and nursing practice environment.

OBJECTIVES: To evaluate the occurrence of patient adverse events in Korean hospitals as perceived by nurses and examine the correlation between patient adverse events with the nurse practice environment at nurse and hospital level. METHODS: In total, 3096 nurses working in 60 general inpatient hospital units were included. A two-level logistic regression analysis was performed. RESULTS: At the hospital level, patient adverse events included patient falls (60.5%), nosocomial infections (51.7%), pressure sores (42.6%) and medication errors (33.3%). Among the hospital-level explanatory variables associated with the nursing practice environment, 'physician- nurse relationship' correlated with medication errors while 'education for improving quality of care' affected patient falls. CONCLUSIONS: The doctor-nurse relationship and access to education that can improve the quality of care at the hospital level may help decrease the occurrence of patient adverse events.

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test.

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

Application of revised nursing work index to hospital nurses of South Korea.

PURPOSE: Based on the Revised Nursing Work Index (NWI-R), this research aimed to develop a Korean Hospital General Inpatient Unit-Nursing Work Index (KGU-NWI). This study also aimed to compare the common points and differences between the subfactors of the KGU-NWI and the subfactors from previous studies. METHODS: Based on opinions from 3,151 nurses in Korean hospital general inpatient unit, this research used 57 items of NWI-R and the principal axis factor analysis for deriving subfactors. We evaluated the convergent validity through factor analysis and the content validity of KGU-NWI in terms of the association between nurses' job outcome and the subfactors derived. RESULTS: Six subfactors and 26 items for KGU-NWI were derived from NWI-R. Among them, 'physician-nurse relationship', 'adequate nurse staffing' and 'organizational support and management of hospital' were the same with results from previous studies. In addition, two subfactors, 'participation of decision-making processes' and 'education for improving quality of care', which were similar with results from previous Korean studies, were newly added by using Korean hospital cases. In contrast to previous Korean studies, a unique subfactor this study found was 'nursing processes'. This research confirmed that the six subfactors were highly correlated with job satisfaction, intention to leave, and quality of health care, which represented a nurse's job outcome. CONCLUSION: KGU-NWI including six subfactors and 26 items is an applicable instrument to investigate nurse work environment in Korean hospital general inpatient unit.

Spectroscopic characterization of the SH2- and active site-directed peptide sequences of a bivalent Src kinase inhibitor.

The spectral properties of the SH2 and active site-directed sequences of the bivalent Src kinase inhibitor Ac-EELL(F5)Phe-(GABA)3-pYEEIE-amide (1) have been determined. Ac-pYEEIE-amide (2) and AcEELL(F5)Phe-amide (3), as well as the amino acids phosphotyrosine (pTyr) and pentafluorophenylalanine (F5)Phe, have been characterized by electronic absorption, fluorescence, and vibrational spectroscopy. Specific and unique marker bands that originate from the phosphate group of pTyr and the fluorinated aromatic ring of (F5)Phe have been identified, with the latter showing some solvent dependence. Peptide 2 was found to have excitation and emission wavelengths emanating from pTyr at 268 and 295 nm, respectively, whereas peptide 3 displayed excitation and emission peaks attributable to (F5)Phe at 274 and 315 nm, respectively. Fourier transform infrared (FT-IR) analysis of the amino acid pTyr identified distinct marker bands at approximately 930, 1090, and 1330 cm(-1) that could be attributed to the phosphate group. These markers were also observed in the IR spectrum of peptide 2. Likewise, peptide 3 displayed a characteristic C-F stretching mode at 961 cm(-1) due to the presence of (F5)Phe, including two C-F reporting ring modes at 1509 and 1527 cm(-1). Identifying and monitoring spectroscopic changes in these marker bands may afford a means to observe the molecular interactions that occur when peptides 1-3 bind to the Src kinase.

Knowledge, beliefs, and behaviors about hypertension control among middle-aged Korean Americans with hypertension.

This report describes the management and control of high blood pressure (HBP) in a sample of middle-aged (40 to 64 years) Korean Americans (KAs) with HBP. Participants in the Self-Help Intervention Program for HBP care (SHIP-HBP), a culturally tailored clinical trial for HBP management in KAs through lifestyle approaches, underwent baseline assessments to determine HBP control status and knowledge, beliefs, and practices related to HPB control. Data were stratified by sex. In all, 445 Korean patients are described. About 55% of the sample were receiving antihypertensive therapy, and less than one-third had controlled BP (< 140/90 mm Hg). Sex differences were observed in terms of clinical characteristics and anti-hypertensive medication use: women were more likely than men to have controlled BP and lower diastolic BP and to have been on HBP medication. Lower rates of smoking, drinking, and overweight or obesity were also observed more frequently in women. Most participants agreed that taking anti-hypertensive medication lowered BP. When asked what the most important behavioral factor was for controlling BP, about a quarter reported cutting down on salt, followed by exercise and medication taking. While poor HBP control remains a common problem that contributes to significant cardiovascular morbidity and mortality, particularly among ethnic minorities, our findings underscore the need to test the beneficial effects of primary and secondary prevention programs, suitably modified to meet the language, cultural, and individual needs of this high-risk population of hypertensive patients.

Barriers to and strategies for recruiting Korean Americans for community-partnered health promotion research.

While increasing numbers of researchers are targeting ethnic minorities in order to address their health disparities, the unique health needs of Korean Americans are not well known to the mainstream community, and only relatively few systematic research studies have been conducted in this "hard-to reach" population. The purpose of this paper is to describe the barriers to recruiting participants for health promotion research and to identify facilitators in the community that can contribute to this effort. We have analyzed data pertaining to the 14 studies we have conducted since 1998, which included a total sample of about 2,400 Korean Americans. We describe in detail the unique recruitment challenges that we have faced in regard to the culture, language, sociodemographic characteristics of the participants, such as gender and age, and other community level barriers. Multiple strategies at different levels (individual and community) to address these issues are discussed.

Enantiopure 1,1'-binaphthyl-based polyoxometalate-containing molecular hybrids.

The first chiral molecular hybrids based on covalently linked polyoxometalate clusters and enantiopure 1,1'-binaphthyl units have been prepared. Their structures have been confirmed by (1)H NMR, FTIR, and ESI-MS measurements. Such hybrids show moderate chiroptical behavior in solutions, and Cotton effects are observed up to 450 nm, indicating chiral extension from the binaphthyl core to the cluster-containing pi-conjugated arms.

Charge-transfer hybrids containing covalently bonded polyoxometalates and ferrocenyl units.

Two new charge-transfer hybrids with one or two ferrocenyl units covalently attached to a hexamolybdate cluster through an extended pi-conjugated bridge have been prepared using Pd-catalyzed coupling reactions on monoiodo- or diiodo-functionalized cluster substrates in over 60% yields. These hybrids have been characterized by (1)H NMR, FTIR, electrospray ionization mass spectrometry, and X-ray diffraction. The electronic spectra of these hybrids show a broad absorption tail extending beyond 550 nm, indicating the existence of charge-transfer transition from the ferrocenyl donor to the cluster acceptor. The observation of the clear charge-transfer transition indicates the contribution of charge-transfer resonance to the ground state in both 2a and 2b even though the donor-acceptor separation distance of 11.29 A is rather long, signaling a through-bond charge-transfer nature made possible by the organic pi-conjugated bridge. Cyclic voltammetry studies reveal a one-electron oxidation wave and a one-electron reduction wave for the hybrid with one ferrocenyl unit. For the one with two ferrocenyl units, a lower reduction potential and a two-electron oxidation wave are observed, indicating negligible electronic interactions between the two ferrocenyl units.

Memory Self-Efficacy and Memory Performance in Older Males.

The study reported here was a secondary analysis of data on 157 males from a larger study of predictors of memory performance in community-dwelling elders. The males' average age was 76 years, with 13 years of education and a Mini-Mental State Exam score of 26. Measures included depression, memory performance, metamemory, and memory self-efficacy. An unusual finding was the multimodal distribution of memory self-efficacy strength scores. Using a median split, the sample was divided into low and high memory self-efficacy groups. The high efficacy group were significantly younger, had larger scores on capacity (+ = high capacity) and change (+ = greater stability). These findings provide new evidence that the memory self-efficacy of aging males influences their perceptions of cognitive performance related to memory.