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다환 방향족 탄화수소기가 도입된 이중보론계 다중공명 형광체의 합성 및 광물리적 특성 연구
No full text최근 높은 효율과 고색순도를 보이는 DABNA 형태의 다중 공명 열활성지연형광체를 최종 형광체로 활용하는 초형광 OLED 소자가 개발되고 있다. 하지만, 다중 공명 열활성지연형광체는 긴 삼중항 수명을 갖기 때문에 삼중항 상태에서 유발되는 심각한 화학적 분해과정을 겪게 된다. 이러한 단점을 개선하고 OLED 소자의 수명과 색순도를 향상시키기 위해 지연형광이 일어나지 않는 발광체의 개발이 필요하다. 본 연구에서는 이중보론계 DABNA 골격에 낮은 삼중항 에너지를 가지는 다환 방향족 탄화수소를 도입함으로써 낮은 삼중항 들뜬 상태(T1) 에너지를 유도하고 이로부터 Dexter 에너지 전달 방지와 삼중항의 비발산성 붕괴를 촉진시킴으로써 삼중항 들뜬상태에서 기인하는 소자 열화를 방지하는 Xyl-diOBN- Pyr(1), Xyl-diOBN-Ph-ant(2) 화합물을 합성하였다. 두 화합물은 톨루엔 용액에서 74%- 99%의 높은 PLQY를 가지며 진한 파란색 영역(455 nm, 450 nm)에서 정상적인 형광을 나타내며 낮은 삼중항 에너지로 인해 큰 △EST 를 나타낸다(0.70 eV, 0.99 eV). 특히 461 ℃ 이상의 높은 열분해 온도를 통해 높은 열적 안정성이 관찰되었다. 화합물의 합성 및 광물리학적 특성에 대한 자세한 내용은 이론적 연구와 함께 논의된다.|Recently, there have been developments in the field of organic light-emitting diode (OLED) devices that utilize DABNA-based multi resonance thermally activated delayed fluorescence (MR-TADF) emitters, which exhibit high efficiency and color purity. However, MR-TADF emitters tend to have long-lived T1 excitons, which can lead to severe chemical degradation processes initiated in the triplet state. To address these drawbacks and improve the longevity and color purity of OLED devices, it is crucial to develop emitters that do not undergo delayed fluorescence. In this study, we synthesized Xyl-diOBN-Pyr(1) and Xyl- diOBN-Ph-ant(2) compounds by introducing Polycyclic Aromatic Hydrocarbons (PAHs) with low triplet energy into the DABNA skeleton, thereby inducing a low T1 energy. This modification facilitates the preventing of Dexter energy transfer and promotes the non-radiative decay of the triplet state, ultimately preventing device degradation originating from the triplet excited state. All compounds exhibited normal fluorescence in the deep blue region (455, 450 nm) with high PLQY ranging from 74% to 99% in toluene solutions. These compounds also displayed a large △EST (0.70, 0.99 eV) due to their low T1 energy. Notably, they exhibited high thermal stability with decomposition temperatures exceeding 461 ℃. The details of synthesis and photophysical properties of compounds will be discussed with theoretical study.Maste
Zinc deficiency triggers hearing loss by reducing ribbon synapses of inner hair cells in CBA/N mice
No full textZinc plays a vital role in our metabolism, encompassing antioxidant regulation, immune response, and auditory function. Several studies have reported that zinc levels correlate with hearing loss. We have previously demonstrated that the auditory brainstem response (ABR) threshold increased in mice fed a zinc-deficient diet. However, the effects of zinc deficiency on hearing were not fully elucidated. The present study investigated whether zinc deficiency affects hearing in association with neuronal components or cochlear structures. CBA/N mice were fed a normal or zinc-deficient diet for 8 weeks and assessed for ABR and distortion product otoacoustic emissions (DPOAE). The cochlear sections were stained with hematoxylin and eosin solution. Also, we observed the expression of synaptic ribbons, neurofilaments, and alpha-synuclein (α-Syn). The 8-week zinc-deficient diet mice had an elevated ABR threshold but no changed DPOAE threshold or cochlear structures. A reduced number of synaptic ribbons of inner hair cells (IHCs) and impaired efferent nerve fibers were observed in the zinc-deficient diet mice. The number of outer hair cells (OHCs) and expression of α-Syn remained unchanged. Our results suggest that zinc-mediated hearing loss is associated with the loss of neuronal components of IHCs
Development and Feasibility Evaluation of Smart Cancer Care 2.0 Based on Patient-Reported Outcomes for Post-Discharge Management of Patients with Cancer
No full textPurpose: A "Smart Cancer Care" platform that integrates patient-reported outcomes (PROs) with management has been established in Korea. This study focused on improving health behaviors and connecting patients to welfare services by introducing and assessing the feasibility of "Smart Cancer Care 2.0," an enhanced version designed for monitoring complications post-cancer treatment.
Materials and methods: Smart Cancer Care 2.0 was developed by conducting a literature review and consulting with expert panels to identify symptoms or variables requiring monitoring and management guidelines based on the treatment type. Qualitative and quantitative surveys were conducted to assess the feasibility of the app and web system based on the experiences of patients with cancer and healthcare workers.
Results: A total of 81 symptoms or variables (chemotherapy-, surgery-, radiotherapy-, rehabilitation-, and health management-related) were selected for management in Smart Cancer Care 2.0. PROs for these symptoms were basically categorized into three severity grades: preventive management, self-treatment, and consultation with a healthcare worker or visit to a healthcare institution. The overall mean scores in the feasibility evaluation by patients and healthcare workers were 3.83 and 3.90 points, respectively, indicating high usefulness.
Conclusion: Smart Cancer Care 2.0 leverages the existing information and communication technologies-based platform, Smart Cancer Care, and further includes health behaviors and welfare services. Smart Cancer Care 2.0 may play a crucial role in establishing a comprehensive post-discharge management system for patients with cancer as it provides suitable interventions based on patients' responses and allows the regularly collected PROs to be easily viewed for streamlined care
Synthesis and Properties of Ni-CNT Nanocomposites Using Electrical Explosion of Wire in Different Conditions
No full textNi-CNT nanocomposites were synthesized via the electrical explosion of wire (EEW) in acetone and deionized (DI) water liquid conditions with different CNT compositions. The change in the shape and properties of the Ni-CNT nano powders were determined based on the type of fluids and CNT compositions. In every case, the Ni nanopowder had a spherical shape and the CNT powder had a tube shape. However, the Ni-CNT nanopowders obtained in DI water exhibited irregular shapes due to the oxidation of Ni. Phase analysis also revealed the existence of nickel oxide when using DI water, as well as some unknown peaks with acetone, which may form due to the metastable phase of Ni. Magnetic properties were investigated using a Vibrating Sample Magnetometer (VSM) for all cases. Nanopowders prepared in DI water conditions had better magnetic properties than those in acetone, as evidenced by the simultaneous formation of super paramagnetic NiO peaks and ferromagnetic Ni peaks. The DI water (Ni:CNT = 1:0.3) sample revealed better magnetic results than the DI water (Ni-CNT = 1:0.5) because it had less CNT contents
Impact of long-term nasal airflow deprivation on sinonasal structures and chronic rhinosinusitis in total laryngectomy patients
No full textObjective: Total laryngectomy (TL) patients are good models in which to evaluate the effects of nasal airflow cessation on the sinonasal tract. Here, we evaluated changes in sinonasal structures and association with sinus opacification in the computed tomography (CT) images 3 years post-TL.
Methods: Patients who underwent TL from 2005 to 2017 in a teaching academic center were reviewed retrospectively. Patients with a final follow-up CT taken less than 3 years after TL, tracheoesophageal puncture, inadequate CT image, or history of sinonasal surgery were excluded. The control group included patients who underwent a partial laryngectomy or hypopharyngectomy without requiring a tracheotomy for more than a month. Altogether, 45 TL patients and 38 controls were selected. The volume of all four paranasal sinuses, inferior turbinate soft tissue volume (ITSTV), maxillary sinus natural ostium (MSNO) mucosal width, and Lund-Mackay scores (LMS) were measured on preoperative and postoperative CT scans.
Results: The mean duration between surgery and the final CT scan was 6.3 ± 2.4 and 5.5 ± 2.3 years for the TL and control groups, respectively. Neither group showed significant changes in the four paranasal sinuses' volume or MSNO mucosa width. The ITSTV decreased significantly, from 4.6 ± 1.3 to 2.8 ± 1.1 mL (p < .001), in the TL group, regardless of the presence of nasal septal deviation, showing ITSTV reduction on both concave and convex sides. By contrast, the control group showed no significant changes in ITSTV. Postoperative LMS changes in both groups were insignificant. The number of patients with LMS aggravation or alleviation was the same in both groups, regardless of preoperative sinus opacification.
Conclusions: Paranasal sinus structures and sinus opacification are not affected significantly by nasal airflow cessation; however, the inferior turbinate mucosa is affected by long-term discontinuation of nasal airflow.
Level of evidence: 4 (case-control study)
Broadband metamaterial polarizers with high extinction ratio for high-precision terahertz spectroscopic polarimetry
No full textThe demand for precise polarizers is increasing to investigate the polarization characteristics of materials non-invasively in the terahertz region. Recently, to address the low extinction ratio and fragile nature of conventional wire-grid polarizers, plasmonic structures and metasurfaces have been proposed. However, the challenge of achieving low transmittance compared to a high extinction ratio, along with the bulky structure due to a thick substrate, remains to be addressed. Here, we present high-efficiency broadband metamaterial polarizers consisting of cross-aligned double-layers of subwavelength metallic slit arrays, leveraging the extraordinary optical transmission and funneling effects. We obtained extinction ratios exceeding 70 dB over a broad frequency range, from 0.2 to 2.5 THz, reaching a maximum extinction ratio of ∼90 dB at 0.7 THz. To investigate the influence of high extinction ratio polarizers on actual measurement results, we measured a non-Hermitian metasurface with asymmetric polarization conversion and analyzed them using the Jones matrix formalism. The results confirmed that the extinction ratio of the polarizer has a significant impact on precise polarization-dependent measurements, especially on cross-polarization measurements. The enhanced performance of our polarizers offers significant potential for sensitive THz systems, paving the way for advancements in polarization analysis of emerging materials and chiral sensing
The Association Between Sputum Culture Conversion and Mortality in Cavitary Mycobacterium avium Complex Pulmonary Disease
No full textBackground: The association between treatment outcome and the mortality of patients with Mycobacterium avium complex pulmonary disease (MAC-PD) with cavitary lesions is unclear. This article assessed the impact of culture conversion on mortality in patients with cavitary MAC-PD.
Research question: Is the achievement of sputum culture conversion in patients with MAC-PD with cavitary lesions associated with the prognosis?
Study design and methods: From 2002 to 2020, a total of 351 patients with cavitary MAC-PD (105 with the fibrocavitary type and 246 with the cavitary nodular bronchiectatic type), who had been treated with a ≥ 6-month macrolide-containing regimen at a tertiary referral center in South Korea, were retrospectively enrolled in this study. All-cause mortality during the follow-up period was analyzed based on culture conversion at the time of treatment completion.
Results: The cohort had a median treatment duration of 14.7 months (interquartile range [IQR], 13.4-16.8 months). Of the 351 patients, 69.8% (245 of 351) achieved culture conversion, and 30.2% (106 of 351) did not. The median follow-up was 4.4 years (IQR, 2.3-8.3 years) in patients with culture conversion and 3.1 years (IQR, 2.1-4.8 years) in those without. For the patients with and without culture conversion, all-cause mortality was 5.3% vs 35.8% (P < .001), and the 5-year cumulative mortality was 20.0% vs 38.4%, respectively. Cox analysis found that a lack of culture conversion was significantly associated with higher mortality (adjusted hazard ratio, 5.73; 95% CI, 2.86-11.50). Moreover, the 2-year landmark analysis revealed a distinct impact of treatment outcome on mortality.
Interpretation: The mortality rate of patients with cavitary MAC-PD who did not achieve culture conversion was significantly higher than that of those with culture conversion
The effects of electrical field workers' perceptions of the functional utility of national technical qualifications on job satisfaction and job performance: Mediating effect of job self-efficacy and moderating effect of digital literacy
No full textThe progress of the Fourth Industrial Revolution and the technological innovation and industrial restructuring resulting from the digital transformation of our society are leading to changes in the structure of the labor market and jobs. In this context, qualifications play a crucial role by providing information about individual occupational abilities, reducing information asymmetry in the labor market, and facilitating the matching of employers and job seekers. National technical qualifications in South Korea see participation from over 2 million individuals annually, with a cumulative acquisition exceeding 32 million, serving as a recognized and signaling mechanism for vocational competencies. However, empirical research from a social and managerial perspective on national technical qualifications is limited, highlighting the need for diverse and in-depth studies to understand the functions and mechanisms of qualification systems.
To verify the research hypothesis, 256 survey data collected from holders of national technical qualifications among attendees of a training course for electrical workers at Association A located in Anyang-si, Gyeonggi-do were analyzed using SPSS, Process Macro, and AMOS programs. The analysis results are as follows. First, the perception of the usefulness of the signaling, leading, and screening functions of national technical qualifications was found to have a positive (+) effect on job satisfaction. Second, the perception of the usefulness of the signaling and leading functions of national technical qualifications was found to have a positive influence on job performance, but the perception of the usefulness of the screening function of national technical qualifications did not show a significant effect. Third, the perception of the usefulness of the signaling and leading functions of national technical qualifications was found to have a positive (+) effect on job efficacy, while the perception of the usefulness of the screening function of national technical qualifications did not show a significant effect. Fourth, job efficacy was found to have a positive effect on job satisfaction or job performance through the perception of the usefulness of the signaling function and leading function of national technical qualifications mediating the relationship with job satisfaction or job performance. Fifth, it was confirmed that a high level of digital literacy positively regulates the relationship between the perception of the usefulness of the signaling function and leading function of national technical qualifications and job efficacy, showing a moderated mediating effect that increases the impact on job satisfaction or job performance.
This study contributes to advancing the understanding of the multifaceted functions of national technical qualifications by introducing perceived functional utility as a precursor variable. By empirically demonstrating direct and indirect effects on job satisfaction, job performance, and job self-efficacy, the study lays the groundwork for more systematic research in the future. Additionally, it provides theoretical support for integrating digital literacy considerations into the design and operation of the national technical qualification system in response to the ongoing digital transformation of our society. In practical terms, it suggests the need for a dual evaluation approach, combining quantitative assessments such as the number of qualification candidates, employment rates, and wages with qualitative evaluations of the functional utility of qualifications. This approach can enhance the quality management system of qualification systems, assess their appropriateness, and deepen understanding of their utility as criteria for personnel management. The study also underscores the necessity of ongoing support for continuous vocational competency development and skill formation post-qualification acquisition, emphasizing the importance of incorporating a certain level of digital literacy into the qualification system.|제4차 산업혁명의 진전과 우리 사회의 디지털 전환에 따른 기술의 혁신과 산업구조의 고도화는 노동시장의 구조와 일자리의 변화로 이어지고 있다. 이 러한 상황에서 자격은 개인이 보유한 직업능력 정보를 제공하여 노동시장에서 정보의 비대칭성을 줄여주고 구인-구직자 간의 합치를 이루는 데에 중요한 역 할을 하게 된다. 우리나라의 국가기술자격은 매년 2백만 명 이상이 응시하고 있으며 누적 취득자 수가 3천2백만 명이 넘어선 직업능력의 인정 및 신호 기 제로서 역할하고 있다. 그러나 사회·경영학 관점에서 국가기술자격과 관련된 실증 연구는 미미한 실정으로 자격 제도의 기능과 메커니즘을 이해하기 위한 다양하고 심도 있는 연구가 필요하다. 본 연구는 국가기술자격의 기능 효용성 인식이 직무만족과 직무성과에 미치는 영향을 분석하여 관계를 설명하고, 이 들 관계에 있어 직무효능감의 매개효과와 디지털 리터러시의 조절효과를 규명 함으로써 국가기술자격 제도의 방향과 시사점을 도출하고자 한다. 연구 가설 검증을 위해 경기도 안양시에 소재한 A 협회에서 전기분야 종사 자를 대상으로 한 훈련과정 참석자 중 국가기술자격 소지자들로부터 수집된 256건의 설문 데이터를 SPSS와 Process Macro, 그리고 AMOS 프로그램을 활 용하여 분석하였다. 분석 결과는 다음과 같다. 첫째, 국가기술자격의 신호기능, 선도기능, 선별기능 효용성 인식은 직무만족에 정(+)의 영향을 미치는 것으로 나타났다. 둘째, 국가기술자격의 신호기능과 선도기능 효용성 인식은 직무성과 에 정(+)의 영향을 미치는 것으로 나타났으나, 국가기술자격의 선별기능 효용 성 인식은 유의미한 영향이 나타나지 않았다. 셋째, 국가기술자격의 신호기능 과 선도기능 효용성 인식은 직무효능감에 정(+)의 영향을 미치는 것으로 나타 났으며, 국가기술자격의 선별기능 효용성 인식은 유의미한 영향이 나타나지 않았다. 넷째, 직무효능감은 국가기술자격의 신호기능과 선도기능 효용성 인식 이 직무만족 또는 직무성과와의 관계에 부분 매개하여 직무만족 또는 직무성 과에 긍정적인 영향을 주는 것으로 나타났다. 다섯째, 높은 수준의 디지털 리 터러시는 국가기술자격의 신호기능과 선도기능 효용성 인식과 직무효능감의 관계를 긍정적으로 조절하여 직무만족 또는 직무성과에 미치는 영향을 높여주 는 조절된 매개효과를 나타내는 것으로 나타났다. 본 연구는 그동안 단일차원의 조사에 그쳤던 국가기술자격의 기능을 자격의 기능 효용성 인식이라는 선행 변인으로 제시하고 직무만족, 직무성과에 직접 효과와 직무효능감과 디지털 리터러시의 간접효과를 실증함으로써 향후 자격 에 대한 보다 체계적인 연구의 기틀 마련과 확장성에 있어 학문적 의의가 있 다. 또한 우리 사회의 디지털 전환을 맞이하여 국가기술자격 제도의 설계와 운영에 있어 디지털 리터러시의 반영에 대한 이론적 근거를 마련하였다. 실무 적으로는 국가기술자격의 효용성 평가에 있어 그간 자격 응시인원, 취업, 임금 과 같은 정량적 평가와 함께 자격의 기능 효용성에 대한 정성적 평가를 병행 함으로써 자격 검정체계의 적정성과 능력의 형성, 인적자원의 관리 기준으로 서의 활용성을 보다 심도 있게 파악하여 자격제도의 품질관리체계를 고도화할 수 있을 것으로 기대된다. 또한, 자격취득과 입직 이후 지속적인 직업능력개발 과 숙련 형성이 이루어질 수 있도록 지원이 필요하며, 자격 제도에 있어 일정 수준의 디지털 리터러시 함양을 반영할 필요가 있음을 시사한다. 주제어: 국가기술자격, 자격의 기능 효용성 인식, 직무만족, 직무성과, 직무효 능감, 디지털 리터러시Docto
Trends in underweight and severe underweight disparities in Korean adults and older adults: a nationwide, repeated cross-sectional study
No full textObjectives: Little is known about the disparities in underweight prevalence among the general population in high-income countries. We investigated the trends in underweight prevalence and disparities across sociodemographic groups among Korean adults and older adults.
Setting and participants: A series of cross-sectional data on Korean national health checkups for adults aged ≥20 years were analyzed from 2005 to 2016.
Measurements: Based on body mass index (kg/m2), underweight was graded as mild (17.0-18.49), moderate (16.0-16.9), and severe (<16.0). Underweight prevalence was compared across sociodemographic subgroups in 2015-2016. Trends in underweight disparities were examined from 2005-2006 to 2015-2016. Multivariable-adjusted odds ratios (ORs; 95% confidence intervals, CIs) were calculated using logistic regression.
Results: Approximately 11-22 million adults were included in each wave. In 2015-2016, the overall prevalence of underweight was 3.6% (men 2.0%, women 5.2%); severe underweight was 0.2% (men 0.1%, women 0.3%). The prevalence of underweight varied by sex and age groups. In men, those aged ≥80 years had the highest prevalence (overall 7.33%, severe underweight 0.84%). In women, those aged 20-29 years had the highest prevalence of overall underweight (14.57%), whereas those aged ≥80 years had the highest prevalence of severe underweight (1.38%). Compared with individuals in the lowest income quartile, men in the highest income had lower ORs of overall (0.59, 95% CI 0.59-0.60) and severe underweight (0.46, 95% CI 0.44-0.48); women in the highest income quartile had a higher OR of overall (1.12, 95% CI 1.12-1.13) but a lower OR of severe underweight (0.89, 95% CI 0.86-0.92). From 2005-2006 to 2015-2016, severe underweight consistently declined in older men but remained constant in women aged ≥80 years, widening sex disparities among older adults. Severe underweight decreased or leveled off in the highest income quartile but steadily increased in the lowest quartile, worsening income disparities.
Conclusion: In this nationwide study, underweight was more prevalent among women, older adults aged ≥80 years, and low-income individuals. Disparities in severe underweight widened across sociodemographic subgroups over time
Cooled radiofrequency ablation of genicular nerves for knee osteoarthritis
No full textKnee osteoarthritis (OA) is a prevalent and debilitating musculoskeletal condition that significantly affects the quality of life of millions of individuals worldwide. In recent years, cooled radiofrequency ablation (CRFA) has become a viable treatment option for knee OA. This review thoroughly evaluated the existing literature on CRFA therapy for knee OA. It delved into the mechanisms behind CRFA, evaluated its clinical efficacy, and investigated potential avenues for future research and application. The insights gained from this review are crucial for healthcare professionals, researchers, and policymakers, offering an updated perspective on CRFA's role as a viable therapeutic option for knee OA