72 research outputs found
Asymmetric formation of γ-lactams via C–H amidation enabled by chiral hydrogen-bond-donor catalysts
No full textChiral γ-lactams are effective structural motifs found in numerous pharmaceutical agents. Despite their importance, current approaches mostly necessitate laborious synthetic steps employing pre-functionalized starting materials under demanding conditions. In this regard, asymmetric C−H amidation can provide an ideal platform for rapid construction of this valuable scaffold from unactivated materials, but unsolved issues have hampered the strategy. Here, we report iridium catalysts that overcome these challenges by utilizing chiral hydrogen-bond-donor ligands. The protocol makes use of easily accessible substrates derived from carboxylic acid, which display excellent efficiency and enantioselectivity towards direct amidation of prochiral sp 3 C−H bonds. Desymmetrization of meso-substrates is also achieved, where two consecutive stereogenic centres are selectively introduced in a single transformation. Computational investigations reveal the presence of crucial hydrogen bonding in the stereo-determining transition states and spectroscopic analysis of the structural analogues further corroborate this non-covalent interaction. © 2019, The Author(s), under exclusive licence to Springer Nature Limite
Iridium‐Catalyzed Chemo‐, Diastereo‐, and Enantioselective Allyl‐Allyl Coupling: Accessing All Four Stereoisomers of (E)‐1‐Boryl‐Substituted 1,5‐Dienes by Chirality Pairing
No full textHere, we report a highly chemo-, diastereo-, and enantioselective allyl-allyl coupling between branched allyl alcohols and α-silyl-substituted allylboronate esters, catalyzed by a chiral iridium complex. The α-silyl-substituted allylboronate esters can be chemoselectively coupled with allyl electrophiles, affording a diverse set of enantioenriched (E)-1-boryl-substituted 1,5-dienes in good yields, with excellent stereoselectivity. By permuting the chiral iridium catalysts and the substrates, we efficiently and selectively obtained all four stereoisomers bearing two consecutive chiral centers. Mechanistic studies via density functional theory calculations revealed the origins of the diastereo- and chemoselectivities, indicating the pivotal roles of the steric interaction, the β-silicon effect, and a rapid desilylation process. Additional synthetic modifications for preparing a variety of enantioenriched compounds containing contiguous chiral centers are also included.11Nsciescopu
세대 조절효과 중심으로
No full text학위논문(석사) -- 서울대학교대학원 : 행정대학원 행정학과(행정학전공), 2023. 8. 임도빈.최근, MZ세대의 잦은 퇴사와 안정적인 직장의 선호도의 급감으로 인해 공공조직은 위기를 겪고 있다. 따라서 본 연구는 이에 대한 원인이 인사공정성에 있다고 판단하고 세대를 조절변수로 설정하여 실증적으로 분석하고 그에 대한 해결책을 탐색하고자 하였다. 세대 간 인사공정성(보수 및 보상, 승진)이 공직만족도에 어떤 차이를 가지고 있는지 확인하고 공직안정성을 높이기 위한 실질적인 함의를 도출하는 데에 본 연구의 목적이 있다.
본 연구의 독립변수는 인사공정성으로 설정하고 이를 분배공정성과 절차공정성으로 세분화하였다. 분배공정성은 보수 및 보상에 해당하고 절차공정성은 승진에 해당한다. 종속변수는 공직만족도이며, 공직만족도에 직무만족도 문항 또한 포함하였다. 조절변수는 세대로 설정하였다. 통제변수는 인구통제학적 변수를 통제변수로 투입하여 분석하였으며 성별, 결혼여부, 학력, 재직기간, 직급, 혼인을 포함하였다. 한국행정연구원에서 실시한 2021년 공직생활실태조사의 데이터를 활용하였고 본 연구의 분석결과의 요약 및 해석은 다음과 같다.
우선, 인사공정성이 공직만족도에 미치는 영향에 대해 분석한 결과 모두 통계적으로 유의한 정(+)의 방향으로 나타났다. 이는 보수 및 보상과 승진이 공직만족도에 중요한 영향을 미친다고 판단할 수 있다.
다음으로 인사공정성과 공직만족도 간의 관계에서 세대가 미치는 조절효과를 분석하였다. 세대는 보수 및 보상, 승진, 인사공정성과 공직만족도 간의 관계에서 통계적으로 유의미한 정(+)의 효과를 보였다. 세부적으로 2030세대가 다른 세대에 비해 인사공정성에 더욱 민감하게 반응함을 확인할 수 있다. 따라서 본 연구는 공직안정성에 보수 및 보상과 승진이라는 인사공정성 요소가 중요하게 작용한다는 것을 확인했으며 공직안정성을 위하여 위 항목을 개선하려는 노력이 필요하다는 함의를 제공하고자 한다.Recently, public organizations are experiencing a crisis due to the frequent resignation of the MZ generation and a sharp decline in their preference for stable work.
Therefore, this study determined that the cause of this was due to personnel fairness, set generation as a moderating variable, empirically analyzed it, and tried to find a solution. Through this, we tried to derive and discuss the practical implications for increasing the stability of public office, which has recently emerged, by confirming what kind of difference intergenerational personnel fairness (remuneration & compensation, promotion) has in public office satisfaction.
This study set the independent variable as personnel fairness and subdivided it into distributive fairness and procedural fairness. Distributive fairness corresponds to the remuneration and compensation items in the questionnaire, and procedural fairness corresponds to promotion. The dependent variable is job satisfaction, and job satisfaction items were also included in public job satisfaction based on previous studies. And the moderating variable was set to generation. For causality between the above variables and the accuracy of the analysis, control variables were set, such as the amount of work and the work environment. In addition, demographic variables were input as control variables, such as gender, marital status, educational background, tenure of service, position, and marital status were included.
As a result of analyzing the effect of personnel fairness on public service satisfaction, all results showed a statistically significant positive (+) direction. This can be judged that remuneration & compensation, and promotion have a significant effect on public service satisfaction.
Next, the moderating effect of generation on the relationship between personnel fairness and satisfaction with public service was analyzed. Generation showed a statistically significant positive (+) effect in the relationship between remuneration & compensation, promotion, and personnel fairness with public service satisfaction.제 1 장 서 론 1
제 1 절 연구 배경 및 목적 1
제 2 절 연구대상 및 범위 3
제 2 장 이론적 배경 5
제 1 절 인사공정성 5
1. 인사공정성의 개념 5
2. 인사공정성의 구성요인 8 제 2 절 공직 만족도에 관한 이론적 논의 14
1. 공직 만족도의 개념 14
2. 공직만족도의 구성요인 18
제 3 절 MZ 세대에 대한 이론적 논의 20
1. 세대의 개념 20
2. 세대의 구분 및 특징 22
3. MZ 세대 25
제 3 장 연구설계 및 분석방법 27
제 1 절 연구방법 및 연구가설 27
1. 연구방법 및 연구모형 27
2. 연구가설 28
제 2 절 분석자료 34
제 3 절 변수의 조작적 정의 및 측정 35
1. 독립변수 35
2. 종속변수 36
3. 조절변수 37
4. 통제변수 38
5. 문항의 신뢰도 및 타당성 40
제 4 절 분석방법 41
제 4 장 분석 결과 및 해석 42
제 1 절 표본의 특성 42
제 2 절 변수들의 기초통계 44
1. 독립변수의 기초통계량 44
2. 종속변수의 기초통계량 45
3. 조절변수의 기초통계량 45
4. 통제변수의 기초통계량 45
제 3 절 변수 간의 상관관계 분석 46
제 4 절 모형 평가 47
제 5 절 연구가설 검증 48
제 5 장 결론 및 제언 59
제 1 절 연구결과 요약 및 해석 59
제 2 절 연구의 의의 및 시사점 60
제 3 절 연구의 정책적 함의 61
참 고 문 헌 63
ABSTRACT 74석
Alcohol consumption, aldehyde dehydrogenase 2 gene polymorphisms, and cardiovascular health in Korea
No full textAlcohol consumption is a serious health issue in Korea in terms of the amount consumed and the behavior related to its consumption. Aldehyde dehydrogenase 2 (ALDH2) is a key enzyme in alcohol metabolism that degrades acetaldehyde to nontoxic acetic acid. The enzyme is coded by the ALDH2 gene, which is commonly polymorphic in East Asian populations. A point mutation in the ALDH2 gene (the rs671 allele) yields an inactive form of ALDH2 that causes acetaldehyde accumulation in the body after alcohol consumption, thereby inhibiting normal alcohol metabolism. Individuals who are homozygous for polymorphism in ALDH2 tend to refrain from drinking alcohol, decreasing their chances of developing alcoholism and exposure to the associated risks. Mendelian randomization (MR) studies have demonstrated that alcohol consumption predicted by ALDH2 genotype is causally related to cardiovascular risks. Moreover, recent MR studies suggest that the ALDH2 variant has mechanistic effects on some disease outcomes or mortality through increased blood levels of acetaldehyde, showing differences therein between heterozygotes (ALDH2*2*2) and homozygotes (ALDH2*1*2) in those who consume alcohol. Accordingly, consideration of ALDH2 genotype in alcohol prevention programs is warranted. In conclusion, strategies that incorporate genetic information and provide an evidential basis from which to help people make informed decisions on alcohol consumption are urgently required.</p
Association of circulating 25-hydroxyvitamin d levels with hypertension and blood pressure values in korean adults:A Mendelian randomization study on a subset of the Korea National Health and Nutrition Survey 2011-2012 population
No full textBACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach.SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method.RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence.CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.</p
Quercetin up-regulates expressions of peroxisome proliferator-activated receptor γ, liver X receptor α, and ATP binding cassette transporter A1 genes and increases cholesterol efflux in human macrophage cell line
No full textCholesterol-laden macrophages trigger accumulation of foam cells and increase the risk of developing atherosclerosis. We hypothesized that quercetin could lower the content of cholesterol in macrophages by regulating the expression of the ATP binding cassette transporter A1 (ABCA1) gene in differentiated human acute monocyte leukemia cell line (THP-1) cells and thereby reducing the chance of forming foam cells. Quercetin, in concentrations up to 30 μM, was not cytotoxic to differentiated THP-1 cells. Quercetin up-regulated both ABCA1 messenger RNA and protein expression in differentiated THP-1 cells, and its maximum effects were demonstrated at 0.3 μM for 4 to 8 hours in incubation. In addition, quercetin increased protein levels of peroxisome proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) within 2 hours of treatment. Because PPARγ and LXRα are important transcriptional factors for ABCA1, quercetin-induced up-regulation of ABCA1 may be mediated by increased expression levels of the PPARγ and LXRα genes. Furthermore, quercetin-enhanced cholesterol efflux from differentiated THP-1 cells to both high-density lipoprotein (HDL) and apolipoprotein A1. Quercetin at the dose of 0.15 μM elevated the cholesterol efflux only for HDL. At the dose of 0.3 μM, quercetin demonstrated effects both on HDL and apolipoprotein A1. Our data demonstrated that quercetin increased the expressions of PPARγ, LXRα, and ABCA1 genes and cholesterol efflux from THP-1 macrophages. Quercetin-induced expression of PPARγ and LXRα might subsequently affect up-regulation of their target gene ABCA1. Taken together, ingestion of quercetin or quercetin-rich foods could be an effective way to improve cholesterol efflux from macrophages, which would contribute to lowering the risk of atherosclerosis.ope
The effect of torque scheduling on the performance and mechanical loads of a wind turbine
No full textBurdens of cardiometabolic diseases attributable to dietary and metabolic risks in Korean adults 2012–2013
No full textPurpose: In line with epidemiological and sociocultural changes in Korea over the past decades, reliable estimation of diseases as a result of dietary and metabolic risks is required. In this study, we aimed to evaluate the contributions of dietary and metabolic factors to cardiometabolic diseases (CMDs) in Korean adults (25–64 years old) during 2012–2013. Materials and Methods: Distribution of risk factors and cause-specific mortality by gender and age per year was obtained from the Korea National Health and Nutrition Examination Survey and Statistics Korea, respectively. The association between the two was obtained from published meta-analyses. The population-attributable fraction attributable to the risk factors was calculated across gender and age strata (male and female, age groups 25–34, 35–44, 45–54, and 55–64) in 2012 and 2013. Results: The results showed that during the period studied, high body mass index [5628 deaths; uncertainty intervals (UIs): 5473– 5781] and blood pressure (4202 deaths; UIs: 3992–4410) were major metabolic risks for CMD deaths, followed by dietary risks such as low intake of whole grain (4107 deaths; UIs: 3275–4870) and fruits (3886 deaths; UIs: 3227–4508), as well as high intake of sodium (2911 deaths, UIs: 2406–3425). Also, males and the younger population were seen more prone to be exposed to harmful dietary risk than their female and older counterparts. Conclusion: The findings provide the necessary information to develop targeted government interventions to improve cardiometabolic health at the population level.</p
Arginase inhibition ameliorates hepatic metabolic abnormalities in obese mice.
No full textWe examined whether arginase inhibition influences hepatic metabolic pathways and whole body adiposity in diet-induced obesity.After obesity induction by a high fat diet (HFD), mice were fed either the HFD or the HFD with an arginase inhibitor, Nω-hydroxy-nor-L-arginine (nor-NOHA). Nor-NOHA significantly prevented HFD-induced increases in body, liver, and visceral fat tissue weight, and ameliorated abnormal lipid profiles. Furthermore, nor-NOHA treatment reduced lipid accumulation in oleic acid-induced hepatic steatosis in vitro. Arginase inhibition increased hepatic nitric oxide (NO) in HFD-fed mice and HepG2 cells, and reversed the elevated mRNA expression of hepatic genes in lipid metabolism. Expression of phosphorylated 5' AMPK-activated protein kinase α was increased by arginase inhibition in the mouse livers and HepG2 cells.Arginase inhibition ameliorated obesity-induced hepatic lipid abnormalities and whole body adiposity, possibly as a result of increased hepatic NO production and subsequent activation of metabolic pathways involved in hepatic triglyceride metabolism and mitochondrial function
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