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Numerical Study on the Dynamic Behavior of Layered Structures under High-Velocity Impact
No full textSpallation occurs when materials exceed their tensile limits under extreme loading conditions, such as high-velocity impacts and shock loading. It is characterized by dynamic void nucleation and fracture growth as tensional waves propagate. Understanding and managing spallation are crucial for maintaining material integrity in extreme circumstances. This study employs numerical methods to investigate spallation and internal pressure in layered structures, which represent the most simplified version of composites. The focus is on understanding the underlying mechanisms and effects of spallation. As the number of layers increases to mimic realistic materials like laminates, the results exhibit behavior similar to that of homogeneous materials, which has significant implications. It is also noteworthy that some layer models of the shock profile, known as the pull-back signal, do not manifest despite the occurrence of internal fractures. This observation suggests that the existing spallation studies on multilayered structures, which rely solely on the shock profile's pull-back signal, may lead to errors in calculating spall strength for composite and layered materials.N
Surgical frequency analysis of patients clustered according to postoperative pain trajectory: a retrospective study
No full textOropharyngeal and orthognathic surgeries cause more postoperative pain than simple dental procedures. The lack of detailed pain pattern analysis after dental surgeries makes pain management challenging. We assessed postoperative pain patterns in patients undergoing various dental surgeries, categorized based on changing pain levels, and identified the most frequent surgical procedures within each pain pattern cluster. Patients aged 18 years and older undergoing elective oral and maxillofacial surgeries under general anesthesia and hospitalized for > 36 h were included. Exclusion criteria were COPD, head injury, adverse drug reactions, substance misuse, severe metabolic disorders, infections, or psychiatric conditions. We retrospectively analyzed previously collected postoperative visual analog scale (VAS) data at 0, 6, 12, 24, and 36 h postoperatively from 790 patients undergoing various dental surgeries under general anesthesia using k-means clustering to identify pain patterns. Surgery type, duration, and patient-controlled analgesia were analyzed for three pain clusters. Cluster 1 had high prolonged initial pain (VAS 7.43 +/- 1.62), mostly involving extensive oropharyngeal cancer surgeries. Cluster 2 experienced moderate pain initially (VAS 5.95 +/- 1.44), steadily declining, typically involving orthognathic surgeries. Cluster 3 reported moderate initial pain (VAS 5.21 +/- 1.49) that decreased rapidly. Extensive procedures were common in Cluster 1, whereas simpler excisions were prevalent in Cluster 3. Postoperative pain varies significantly according to the extent and invasiveness of surgery. Identifying specific pain trajectories based on detailed surgical assessments can enhance preemptive pain management and aid clinicians in predicting and managing postoperative pain.Y
Colorimetric identification of colorless acid vapors using a metal-organic framework-based sensor
No full textIn terms of safety and emergency response, identifying hazardous gaseous acid chemicals is crucial for ensuring effective evacuation and administering proper first aid. However, current studies struggle to distinguish between different acid vapors and remain in the early stages of development. In this study, we propose an on-site monitorable acid vapor decoder, MOF-808-EDTA-Cu, integrating the robust MOF-808 with Cu-EDTA, functioning as a proton-triggered colorimetric decoder that translates the anionic components of corrosive acids into visible colors. The sensor exhibits a cyan-to-yellow shift when exposed to HCl vapor and can visually differentiate various acidic vapors (HF, HBr, and HI) through unique color changes. Furthermore, the compatibility of the MOF-based sensor with multiple metal ions having atomic-level dispersion broadens its discrimination range, enabling the identification of six different colorless acid vapors within a single sensor domain. Additionally, by incorporating a flexible polymer, the MOF-808-EDTA-Cu has been successfully processed into a portable miniaturized acid sensor, exhibiting distinct color changes that can be easily monitored by the naked eye and camera sensors. This provides experimental validation as a practical sensor capable of on-site 24-hour monitoring in the real world.Y
Curcumin and EGCG combined formulation in nanostructured lipid carriers for anti-aging applications
No full textCurcumin (Cur) and epigallocatechin gallate (EGCG), the primary active compounds in turmeric and green tea, respectively, have been investigated for their anti-aging potential. The Cur and EGCG combination was encapsulated in sustained-release nanostructured lipid carriers (NLCs) to enhance their bioactivities and pharmaceutical properties. A significant enhancement in the antioxidant activities of the Cur and EGCG combination was observed at an optimal ratio, as demonstrated by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (118.83 f 3.78 %), ferric ion reducing antioxidant power assay (217.25 f 13.45 %), and lipid peroxidation inhibition assay (106.08 f 12.93 %), compared to Cur alone without compromising the antioxidant activities and total phenolic content of EGCG. This is due to the enhancement of total phenolic content of the combination of 218.83 f 10.57 %. For anti-aging activities, the combination exhibited stimulation of SIRT1 protein and inhibition of collagenase and elastase of 27.53 f 0.73%, 43.70 f 1.05% and 51.76 f 6.52% compared with that achieved with Cur alone, respectively. The incorporation of the Cur and EGCG combination into NLCs resulted in high entrapment efficiencies of 98.60 f 0.05 % for Cur and 98.40 f 0.08 % for EGCG, with corresponding loading capacities of 0.789 f 0.001 % and 3.935 f 0.003 %, respectively. When formulated NLCs into an emulgel base, the system demonstrated sustained release profiles over 48 h, with 12.82 f 0.99 % release of Cur and 63.77 f 5.76 % release of EGCG. Significant skin retention was also observed after 24 h, with 23.88 f 1.71 % Cur and 22.79 f 4.65 % EGCG retained in the skin. Therefore, Cur: EGCG-loaded NLCs in emulgel can deliver the active compounds into the dermis, enhancing skin penetration, sustained delivery, and anti-aging activity superior to each conventional single active compound in topical formulations.Y
Microbiome-emitted scents activate olfactory neuron-independent airway-gut-brain axis to promote host growth in Drosophila
No full textWhile it is now accepted that the microbiome has strong impacts on animal growth promotion, the exact mechanism has remained elusive. Here we show that microbiome-emitted scents contain volatile somatotrophic factors (VSFs), which promote host growth in an olfaction-independent manner in Drosophila. We found that inhaled VSFs are readily sensed by olfactory receptor 42b non-neuronally expressed in subsets of tracheal airway cells, enteroendocrine cells, and enterocytes. Olfaction-independent sensing of VSFs activates the airway-gut-brain axis by regulating Hippo, FGF and insulin-like growth factor signaling pathways, which are required for airway branching, organ oxygenation and body growth. We found that a mutant microbiome that did not produce (2R,3R)-2,3-butanediol failed to activate the airway-gut-brain axis for host growth. Importantly, forced inhalation of (2R,3R)-2,3-butanediol completely reversed these defects. Our discovery of contact-independent and olfaction-independent airborne interactions between host and microbiome provides a novel perspective on the role of the airway-gut-brain axis in microbiome-controlled host development.Y
Soft Cardiac Patch Using a Bifacial Architecture of Adhesive/Low-Impedance Hydrogel Nanocomposites and Highly Conductive Elastomer Nanocomposites
No full textSoft implantable multichannel cardiac electrode arrays that establish direct monolithic interfaces with the heart are key components for advanced cardiac monitoring and electrical modulation. A significant technological advancement in this area is the development of stretchable conductive nanocomposites, fabricated through the integration of metallic nanomaterials and elastic polymers, aimed at achieving both high electrical conductivity and mechanical elasticity. Despite these advances, further progress in material performance and device designs is required to ensure seamless, reliable, biocompatible, and high-fidelity cardiac interfacing. Herein, the development of a soft multichannel cardiac patch based on a bifacial architecture of adhesive/low-impedance hydrogel nanocomposites and highly conductive elastomer nanocomposites is reported. The bifacial design facilitates the integration of the cardiac patch between the heart and other tissues/organs can be achieved. The hydrogel nanocomposite layer, positioned on the epicardial side, provides stable adhesion to the target cardiac tissue and enables low-impedance biocompatible interfacing with the heart, while the elastomer nanocomposite layer, positioned on the opposite side, offers high electrical conductivity for facile electrophysiological signal transfer and a low-friction surface minimizing unwanted interactions with surrounding tissues. The effectiveness of this bifacial patch in multiple applications involving various cardiac signal recordings and electromechanical modulation demonstrations is showcased.Y
공공 시설물 전염병 예방 정책의 접촉 빈도 저감 효과 및 건물 운영 효율성 분석
No full textThis study evaluates the impact of Non-Pharmaceutical Intervention (NPI) policies on airport operations using an agent-based simulation model of Incheon International Airport Terminal 2. Various NPI policies, such as social distancing, self-check-in rates, and duty-free shop closures, were evaluated for their ability to reduce passenger contact while maintaining operational efficiency. The findings revealed that social distancing reduced congestion and passenger interactions but negatively impacted efficiency. Increasing self-check-in rates alleviated congestion at check-in counters and improved passenger flow, but excessively high rates caused bottlenecks in other areas, increasing passenger contact. Similarly, closing duty-free shops reduced crowd density and transmission risk in specific areas, but excessive closures led to a balloon effect, where limited space resulted in overcrowding elsewhere. The results highlight the need for a balanced approach to NPI policies, supplemented with additional strategies to mitigate overcrowding and maintain operational efficiency.N
Making homes survival places: the experience and practices in fear of crime of young women living alone in Seoul
No full textThis study examines the vulnerability of young women living alone in Seoul, South Korea, to crime and their fear of victimization. It investigates how their experiences shape their perception of home and explores their strategies to create a sense of security within their living spaces. By conducting in-depth interviews with nine participants aged 26-31 in Gwanak-gu, Seoul, the study identifies key factors contributing to their experience and recognition of fear at home. It further highlights these women's strategies to protect their homes and practices to alleviate anxiety and establish safety. The findings reveal that for single young women in Seoul, the concept of homes plays a significant role as a site of survival, where they strive to protect themselves and their homes from various fears and potential crime victimization. This research contributes to the interdisciplinary discourse on housing and gender studies, shedding light on the unique challenges faced by young women living alone and emphasizing the importance of understanding their experiences and developing supportive policy interventions.N
식이요인의 암 발생 기여위험도
No full textBackground: The population attributable fraction (PAF) indicates the proportion of disease cases in a given population that can be attributed to a specific factor, assuming a causal relationship. In other words, it quantifies the extent to which that factor contributes to disease occurrence. PAF calculation methods have been applied to studies factors and several, studies have reported PAFs for dietary contributors to overall or specific cancer risks. Our team has conducted several PAF studies and presents findings on the contributions of dietary factors to cancer risk in the Korean population. Current Concepts: For colorectal cancer, the PAF of dietary factors is 34.9%, with insufficient whole grain intake contributing the largest share (16.6%). For gastric cancer, dietary factors have a PAF of 18.6%, with excessive intake of salted vegetables contributing the most (16.0%). Notably, the PAFs for inadequate whole grain and milk consumption were higher than those reported in previous studies, while the PAFs for other dietary factors fell within the expected range. These findings emphasize the need to prioritize interventions that effectively reduce the diet-attributable cancer burden. Discussion and Conclusion: Country-specific PAF estimates are crucial for developing effective cancer prevention strategies tailored to the Korean population. To better apply dietary PAF estimates, future studies should (1) integrate data from existing and ongoing cohort studies to determine Korea-specific relative risks, (2) estimate dietary prevalence using assessment tools that capture long-term dietary habits, and (3) establish optimal intake levels specific to the Korean context.Y
How Far Should We Develop?: 30 Years of Sihwa Lake, a Duet of Pollution and Improvement
No full text이 글은 시화호와 시화지구 개발이 초래한 환경오염과 개선 과정을 비판적으로조망하며, 인간과 비인간 존재가 공존할 가능성을 모색하는 것을 목적으로 한다. 1977년수도권 인구 분산 정책의 일환으로 반월특수지역이 지정되었고, 1980년대 공업단지 확대와 간척농지 개발이 추진되면서 시화지구 개발이 본격화하였다. 이 개발은 국토 개조 를 표방한 하이 모더니즘이 표출된 것이면서, 중동 건설경기 침체로 인한 국내 건설업체 부실을 만회하려는 전두환 정권의 의도가 개입된 것이었다. 대규모 간척으로 주민 이주와 전업이 발생하고 갯벌 생태계가 파괴되었다. 1994년 시화방조제가 완공되면서 군자만은 인공 자연 시화호로 변했다. 그러나 반월공단의 폐수 방류와 생활하수 유입으로시화호는 죽음의 호수가 되었다. 생태 재앙이 발생하고, 공사 과정에서의 부실과 한국수자원공사 등 정부 기관의 무책임이 밝혀지면서 주민과 환경단체는 적극적으로 정부를비판하며 저항했다. 이후 2000년대 해수 유통, 하수처리시설 보완, 조력발전소 가동 등으로 수질이 개선되고 생태계가 회복되었다. 그러나 시화MTV, 송산그린시티, 대송단지등 계속되는 개발은 시화호 생태계의 지속가능성에 한계를 드러내고 있다. 시화호 사례는 무분별한 개발이 지속될 때 생태 재앙이 일어날 수 있음을 경고한다. 인간과 비인간존재가 공존할 대안으로 시화호와 같은 특정 생태계에 법인격을 부여하는 방안 등을 고려할 필요가 있다.N