Earticle

Objective To investigate the impact of tracheostomy tube capping on swallowing physiology in stroke patients with dysphagia via videofluoroscopic swallowing study (VFSS).Methods This study was conducted as a prospective study that involved 30 stroke patients. Then, 4 mL semisolid swallowing was conducted with capping of the tracheostomy tube or without capping of the tracheostomy tube. The following five parameters were measured: laryngeal elevation, pharyngeal transit time, post-swallow pharyngeal remnant, upper esophageal sphincter width (UES), and penetration-aspiration scale (PAS) score. Results On assessment of the differences in swallowing parameters during swallowing between ‘with capping’ and ‘without capping’ statuses, statistically significant differences were found in the post-swallow pharyngeal remnant (without capping, 48.19%±28.70%; with capping, 25.09%±19.23%; p<0.001), normalized residue ratio scale for the valleculae (without capping, 0.17±0.12; with capping, 0.09±0.12; p=0.013), normalized residue ratio scale for the piriform sinus (without capping, 0.16±0.12; with capping, 0.10±0.07; p=0.015), and UES width (without capping, 3.32±1.61 mm; with capping, 4.61±1.95 mm; p=0.003). However, there were no statistically significant differences in laryngeal elevation (x-axis without capping, 2.48±1.45 mm; with capping, 3.26±2.37 mm; y-axis without capping, 11.11±5.24 mm; with capping, 12.64±6.16 mm), pharyngeal transit time (without capping, 9.19± 10.14 s; with capping, 9.09±10.21 s), and PAS score (without capping, 4.94±2.83; with capping, 4.18±2.24).Conclusion Tracheostomy tube capping is a useful way to reduce post-swallow remnants and it can be considered an alternative method for alleviating dysphagia in stroke patients who can tolerate tracheostomy tube capping when post-swallow remnants are observed.

Objectives: This study was conducted to identify factors determining the toxicity of manufactured silver nano-particles (AgNPs) on aquatic organisms. Methods: For this purpose, we prepared several AgNPs with varied characteristics, including hydrodynamic size (nano-$^{ABC}Ag^{Cit}\;vs$-sized-$^{ABC}Ag^{Cit}$), impurities ($^{ABC}Ag$ stock vs $^{ABC}Ag$), and citrate capping ($^{ABC}Ag^{Cit}$), using a commercially available manufactured AgNP ($^{ABC}Ag$ stock). Acute tests were conducted using larval zebrafish (Danio rerioI). In addition, in order to determine the ecotoxicological potentials of various capping agents, toxicity tests were conducted with microbes, waterfleas, and fish for eight different capping agents that are used for NPs. Results: The toxicity of AgNPs in terms of 96 h fish $LC_{50}$ increased in the following order: $^{ABC}Ag$ stock < $^{ABC}Ag=^{ABC}Ag^{Cit}=nano-^{ABC}Ag^{Cit}$ < ${\mu}$-sized-$^{ABC}Ag^{Cit}$ < $AgNO_3$. After removing impurities by dialysis, 96 h $LC_{50}$ value decreased significantly from $126.6{\mu}g/L$ (95% confidence intervals [CI]: 107.0-146.2) ($^{ABC}Ag$ stock) to $78.6{\mu}g/L$ (CI: 72.7-84.8) ($^{ABC}Ag$). For ${\mu}$-sized-$^{ABC}Ag^{Cit}$ (ranging between 3.9 and 40.6 nm) and $^{ABC}Ag^{Cit}$ (40.6 nm and $9.1{\mu}m$), the 96 h $LC_{50}$ of the former ($43.9{\mu}g/L$, CI: 36.0-51.7) was approximately two-fold lower than that of the latter ($87.0{\mu}g/L$, CI: 73.5-100.3). Conclusions: In this study, we found that for acute lethality, the contribution of impurities and particle size was significant, but that of citrate was negligible.

Actin polymerization is essential for various stages of mammalian oocyte maturation, including asymmetric spindle migration, cortical actin cap formation, polar body extrusion, and cytokinesis. The heterodimeric actin capping protein (CP) is an essential element of the actin cytoskeleton. It binds to the fast-growing (barbed) ends of actin filaments, thereby blocking their elongation, and plays essential roles in various actin-mediated cellular processes. However, the roles of CP in mammalian oocyte maturation are poorly understood. We investigated the roles of CP in mouse oocytes, and found that CP is essential for correct asymmetric spindle migration and polar body extrusion. CP colocalized with cortical actin in immature oocytes, but its localization changed during maturation. Experiments in which CP was knocked down or ectopically overexpressed revealed that this protein is critical for Perturbations in the level of CP impaired spindle migration and polar body extrusion during oocyte maturation. Taken together, this study shows that CP is an essential component of the actin cytoskeleton machinery that plays crucial roles in oocyte maturation.

New synthetic route and characterization of alkyl-capped nanocrystalline silicon (R-n-Si) were achieved from the reaction of silicon tetrachloride with sodium/benzophenone ketal reducing agent followed by n-butyllithium. Surface of silicon nanoparticles was derivatized with butyl group. Effect of oxidation of silicon nanoparticle with benzophenone was investigated for their stabilization. Optical characteristics of silicon nanoparticles were characterized by fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), and photoluminescence (PL) spectroscopy. Butylcapped silicon nanoparticles exhibited an emission band at 410 nm with excitation wavelength of 360 nm. Average size of n-butyl-capped silicon nanoparticles was obtained by particle size analyzer (PSA) and transmission electron microscopy (TEM). Average size of n-butyl-capped Si nanoparticles was about 6.5 nm.

Contaminated sediments with hexavalent chromium (Cr(VI)) and naphthalene (NAP) have posed a significant risk to sediment environment. This study introduced an activated mulbbery biochar (MBK) with alkali (K2CO3) to stabilize Cr(VI) and NAP from sediment. Moreover, MBK exhibited remarkably large specific surface area of 2213 m2/g. and high sorption performances of Cr(VI) and NAP were 340.1 mg/g and 250 mg/g, respectively. Furthermore, sorption kinetics and thermodynamic sorption revealed fast sorption equilibrium, with higher temperatures favoring sorption of both Cr(VI) and NAP. Moreover, environmentally relevant concentrations of DOM significantly enhanced the sorption of both Cr(VI) and NAP onto MBK. While low levels of Cr(VI) (60 mg/L) did not affect NAP sorption, higher concentrations of Cr(VI) suppressed NAP sorption. Microcosm studies were conducted to evaluate the effectiveness of two different sediment amendment techniques, in-situ mechanical mixing (MIX) and in-situ capping (CAP), in stabilizing Cr(VI) and NAP. Both techniques demonstrated a 99% reduction in the flux of Cr(VI) and NAP from water to sediment. However, the in-situ MIX technique exhibited a higher reduction in Cr(VI) and NAP concentrations in pore water compared to the CAP technique. Moreover, MBK demonstrated higher stabilization efficiency for Cr(VI) and NAP compared to CAC, indicating the practicality of using MBK instead of CAC for Cr(VI) and NAP sediments. These findings offer valuable strategies for the in-situ stabilization of Cr(VI) and NAP in contaminated sediments using MBK.

Anthropogenic activities led to the discharge of heavy metals into aquatic systems, which are eventually deposited in sediment. Physical disturbances and environmental changes can trigger the release of these heavy metals from sediment creating potential risks to both environment and human health. Biochar has been recognized as an excellent adsorbent for restoring heavy metal-contaminated sediment. In this study, we developed two rice husk biochar (RBC) composite pellets using hydroxyapatite (HAP), and magnesium oxide (MgO), as an additive. As formed biochar composites are called HAP@RBC-P and MgO@RBC-P. The physicochemical properties of the fabricated composites were evaluated by multiple characterization techniques. The composites HAP@RBC-P and MgO@RBC-P exhibited better adsorption performance for Pb(II), Cd(II), and Zn(II) compared to RBC. The efficiency of the composites in controlling the release of heavy metals from sediment was evaluated by mixing them with the sediment. After 28 days of cover, both HAP@RBC-P and MgO@RBC-P effectively inhibited the release of Pb(II), Cd(II), and Zn(II) from sediment to overlying water, with inhibition efficiencies ranging from 80.4% to 93.65%, 57.52% to 95.2%, and 46.55% to 84.0% for HAP@RBC-P, and 50.0% to 81.4%, 70.6% to 88.6%, and 67.1% to 88.2% for MgO@RBC-P. Both biochar composite pellets exhibited high inhibition efficiencies for the release of heavy metals from the sediment composite mix. The practical applicability of these composites was assessed through a toxicity test on sediment-dwelling organisms (Lumbriculus variegatus). After a 28-day experiment, the survival rate of the Lumbriculus variegates was over 90% for both types of biochar composite pellets. indicating that the biochar composite pellet was an environmentally friendly biochar material.

This study aims to assess the effectiveness of activated carbon (AC) and crushed concrete (CC) as capping material to block the release of nitrogen, phosphorus, and organic substance from reservoir sediments. The efficiency of AC and CC as capping material was evaluated in a reactor in which a 1 or 3 cm thick layer of capping materials was placed on the sediments collected from Mansu reservoir in Anseong-city. Dissolved oxygen (DO) concentration, total nitrogen (T-N), total phosphorus (T-P), and chemical oxygen demand (COD) concentration in reservoir water above the uncapped sediments and capping material were monitored for 45 days. The release rate of T-N was in the following increasing order: AC 3 cm ($1.18mg/m^2{\cdot}d$) < CC 1 cm ($2.66mg/m^2{\cdot}d$) < AC 1 cm ($2.94mg/m^2{\cdot}d$) < CC 3 cm ($3.42mg/m^2{\cdot}d$) < uncapped ($4.59mg/m^2{\cdot}d$). The release rate of T-P was in the following increasing order: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($0.03mg/m^2{\cdot}d$) < AC 1 cm capped ($0.07mg/m^2{\cdot}d$) < uncapped ($0.24mg/m^2{\cdot}d$). The release of nitrogen and phosphorus were effectively blocked by AC capping of 3 cm thickness, and CC capping of 3 cm thickness effectively controlled the release of phosphorus. The order of increasing COD release rate was as follows: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($5.03mg/m^2{\cdot}d$) < AC 1 cm ($7.28mg/m^2{\cdot}d$) < uncapped ($10.05mg/m^2{\cdot}d$), indicating that AC and CC capping effectively interrupted the release of organic contaminants from the sediments. It was concluded that AC and CC could effectively block the release of T-N, T-P and COD release from contaminated reservoir sediments.

This study aims to assess the effectiveness of limestone, zeolite, and crushed concrete as capping material to block the release of heavy metals (As, Cu, Cr, Ni, and Pb) and reduce the sediment oxygen demand. The efficiency of limestone, zeolite, and crushed concrete was evaluated in a reactor in which a 1-cm thick layer of capping materials was placed on the sediments collected from Inchon north harbor. Dissolved oxygen concentration and heavy metal concentration in seawater above the uncapped sediments and capping material were monitored for 17 days. The sediment oxygen demand was in the following increasing order: crushed concrete ($288.37mg/m^2{\cdot}d$) < zeolite ($428.96mg/m^2{\cdot}d$) < limestone ($904.53mg/m^2{\cdot}d$) < uncapped ($981.34mg/m^2{\cdot}d$). The capping materials could reduce the sediment oxygen demand by blocking the release of biochemical matters consuming dissolved oxygen in seawater. It was also shown that zeolite and crushed concrete could effectively block the release of Cu, Ni, and Pb but those were not effective for the interruption of As and Cr release from marine contaminated sediments.

본 연구에서는 하천 및 호소수 내 오염퇴적물의 영양염류 용출 억제를 하기 위하여 복합유용미생물제재가 고정화된 반 응성 피복재를 제작하고 퇴적물에서의 영양염류 용출 저감과 수질정화 효과를 분석하였다. 반응성 피복재 성상(N1, N2) 과 입자 크기(0.8 mm 이하, 23 mm 이하)에 따라 제작하였다. 호소수에서 채취한 시료를 대상으로 반응성 피복재를 적용 한 결과 N1의 경우 대조군과 비교하여 COD는 약 70%, T-N은 34%, T-P는 80%의 용출 차단율을 나타냈으며 N2의 경 우 COD는 약 60%, T-N은 40%, T-P는 85%의 결과를 나타냈다. 실험 결과 N2 반응성 피복재의 경우 유기물 및 영양염 류의 높은 용출 차단율을 보였다. 본 연구 결과를 토대로 하천 및 호소수에 적용 시 높은 수질 개선 효과를 기대할 수 있 는 친환경적인 자연정화 처리 기술이다.

Contaminants such as organic matters and nutrients in rivers and lakes are removed from the water and accumulated in the sediments. When they are released into the water column again, they bring to harmful effects on the water quality and aquatic ecosystems. In this study, the effect on reducing nutrient release in sediments and purifying water was evaluated with reactive capping material immobilizing effective microorganisms. Reactive capping material were produced as N1 and N2. The experimental results showed that release block efficiencies with N1 were COD 70%, T-N 34% and T-P 80% and N2 release block efficiencies were COD 60%, T-N 40% and T-P 85% respectively. N2 containing particulates less than 0.8 mm showed the higher release block efficiency for organic matters and nutrients. Based on the above results, it is expected that the application of capping material will contribute to improving the natural purification.

유속이 약한 하천이나 호소에 침강된 유기물, 영양염류, 유해화학물질 등의 오염물질은 일단 수중으로부터 제거되어 퇴적물 속에 축적되었다가 확산, 재 부유, 생물교란 등의 물리 화학 생물학적 과정에 의해 다시 수층으로 용출되어 수질 및 수생생태에 직 간접적인 악영향을 미칠 수 있게 된다. 특히 인은 수중생태계의 일차 생산량을 결정하는 중요한 물질중의 하나로 수체 내 물질순환 과정에서 주로 퇴적물에 저장되는 원소로 물리적인 교란 및 생 화학적 작용에 의해 수층으로용출되어 부영양화현상을 가속시키는 것으로 알려져 있다. 본 연구에서는 수층 미생물의 영향을 고려한 경우(호소수)와 미생물의 영향을 배제한(증류수)경우로 구분하여 각각 다른 capping 소재를 적용하여 퇴적물에서의 인 용출 저감 효과를 분석하였다. 실험 결과 화학적소재인 Fe-Gypsum, $SiO_2$-Gypsum로 capping을 할 경우, control보다 인 용출을 약 40% 이상 저감시키는 것을 확인할 수 있었다. 또한 복합소재인 granule gypsum+Sand는 약 50% 이상 용출을 저감 효과가 나타났다. 따라서 화학적 소재인 granule-gypsum과 그 위에 모래와 같은 친환경소재로 capping을 한다면 인 용출 저감에 효과적일 것으로 판단된다. Capping 처리 전후의 퇴적층내의 인 성상변화를 살펴본 결과, gypsum 투입에 의하여 호소 퇴적층에 존재하는 인이 용출되기 어려운 안정한 형태인 apatite-P 변화된 것으로 확인되었다. 이상의 결과를 토대로 capping 기술의 적용을 통하여 하천 및 호소 퇴적물에서 발생되는 인 용출에 대한 저감 효율을 기대할 수 있을 것으로 사료된다.

Contaminants such as organic matters, nutrients and toxic chemicals in rivers and lakes with a weak flow rate are first removed from the water and accumulated in the sediments. Subsequently, they are released into the water column again, posing direct/indirect adverse effects on the water quality and aquatic ecosystems. In particular, phosphorus is known to accelerate the eutrophication phenomenon when it is released into the water column via physical disturbance and biological/chemical actions as one of important materials that determine the primary production of aquatic ecosystems and an element that is stored mainly in the sediments in the process of material circulation in the body of water. In this study, the effect on reducing phosphorus release in sediments was analyzed by applying different capping materials to lake water, where the effect of aquatic microorganisms is taken into account, and to distilled water, where the effect of microorganisms is excluded. The experimental results showed that capping with chemical materials such as Fe-gypsum and $SiO_2$-gypsum further reduced the phosphorus release by at least 40% compared to the control case. Composite materials like granule gypsum+Sand showed over 50% phosphorus release reduction effect. Therefore, it is determined that capping with chemical materials such as granule-gypsum and eco-friendly materials such as sand is effective in reducing phosphorus release. The changes in phosphorus properties in the sediments before and after capping treatment showed that gypsum input helped to change the phosphorus that is present in lake sediments into apatite-P, a stable form that makes phosphorus release difficult. Based on the above results, it is expected that the application of capping technology will contribute to improving the efficiency of reducing phosphorus release that occurs in river and lake sediments.

기존의 Flip-chip형 발광소자에에서의 Ag반사층 상에 NiZn 합금을 적용한 구조를 통하여 기존보다 향상된 열적 안정성과 전기적, 광학적 물성을 얻고 이에 따른 오믹 메커니즘의 규명을 실시하였다.

최근 실온에서 약 40％ 이상의 높은 자기저항(magnetoresistance, MR)을 나타내는 자기 터널 접합(magnetic tunnel junction, MTJ)이 보고되면서 비휘발성 자기메모리로의 응용을 눈앞에 두고 있다.[1]. 이에 본 실험에서는 Substrate / Ta (base electrode) / NiFe / PtMn (AF pinning layer) / CoFe (pinned) / Ru / CoFe (fixed) / Al-O/ CoFe (free) / NiFe (free) / Ta & Ru (Capping Layer)과 같은 MTJ 증착 구조를 사용하여, MTJ의 보다 향상된 특성을 확보하기 위한 노력으로서 Al-O 두께, 어닐링 조건(Field Intensity ＆ Sequence)변화 등을 시도하였다. (중략)

Zinc tin oxide (ZTO) thin films were deposited using atomic layer deposition (ALD) to ensure precise thickness control and uniformity. However, the low-temperature processing of ZTO often results in increased defect states, leading to degraded electrical performance. To address this issue, metal capping layers (Al or Au) were added to the ZTO active layer. The capping layers modulate electron energy levels at the interface, increase carrier density, and reduce interface traps, thereby improving electrical properties. Aluminum (Al) and gold (Au) were evaluated for their impact on key performance metrics, including electron mobility (µ_sat), threshold voltage (V_T), subthreshold swing (SS), and on/off current ratio (I_ON/OFF). Results show that Al-capped ZTO thin-film transistors (TFTs) exhibited enhanced performance due to the lower work function of Al (4.0 eV), which facilitates electron injection and reduces contact resistance. In contrast, Au-capped ZTO TFTs showed decreased performance due to electron depletion caused by the higher work function of Au (5.1 eV). Optical analyses, including UPS and UV-Vis, revealed the band structure and work function of the ZTO thin films. This study concludes that the choice of capping material and its design parameters play a critical role in optimizing TFT performance, offering valuable insights for the development of next-generation high performance TFT devices.

다양한 신경성 퇴행 질병을 유발하는 아밀로이드 섬유의 기계적 특징에 대한 이해는 아밀로이드 성장 메커니즘에 직접 관련되어 있기 때문에 질병 역학적 관점에서 많은 연구 진행 되어 왔다. 최근 아밀로이드 섬유의 높은 물성 값과 자가 결합능력을 통해 새로운 재료로 이용 하려는 시도가 진행되고 있다. 본 연구에서는 심혈관 질환을 유발하는 transthyretin($TTR_{105-115}$)의 핵심 영역의 기계적 특성을 분자 동역학 전산 역학을 통해 평가했다. 특히 end-terminal capping의 효과가 $TTR_{105-115}$의 구조적 안정성에 미치는 영향을 평가했다. 인장모사 분자 동역학을 통해(steered molecular dynamics, SMD) 기계적 거동과 물성을 측정하였다. 재료의 기계적 특성에 영향을 주는 인자를 밝히고 자연 모사 재료로써의 활용 가능성에 대한 제시를 하였다.

The understanding of the mechanical properties of amyloid fibers, which induce various neurodegenerative diseases, is directly related to the amyloid growth mechanism. Diverse studies have been performed on amyloid fibers from the viewpoint of disease epidemiology. Recently, attempts have been made to use amyloid fibers as new materials because of their notable mechanical properties and self-aggregation abilities. In this study, the mechanical properties of transthyretin (TTR105-115), which induces cardiovascular disease, were evaluated using a molecular dynamics (MD) simulation. In particular, the effect of the end-terminal capping on the structural stability of TTR105-115 was evaluated. The mechanical behavior and properties of TTR105-115 were measured by steered molecular dynamics (SMD). We clarified the factors affecting the mechanical properties of these materials and suggested the possibility of utilizing them as nature inspired materials.

목적 : 고식적인 안구내용제거술로는 큰 삽입물을 삽입할 수 없는 안구로가 심한 환자에서 360도 적도부 둘레 공막이완절개법인 Scleral capping방법을 이용한 안구내용제거술기와 수술 결과를 보고하고자 한다. 대상과 방법 : 2002년 9월부터 2006년 2월까지 Scleral capping 방법을 시행받은 환자 20명 20안을 후향적으로 조사하였다. 안구내용제거술 후 적도부 둘레에 360도 공막이완절개를 시행하고 다공성 폴리에틸렌(MedporⓇ) 안와삽입물을 삽입하였다. 전, 후부 공막이완절개창은 5-0 braided polyester로 느슨하게 봉합하였다. 결과 : 수술 전 초음파와 전산화단층촬영으로 측정한 안축장은 평균 16.8 mm 였으며, 20 mm이상의 MedporⓇ 안와삽입물을 삽입하였다. 수술 후 추적 관찰은 29.1개월 이었다. 의안의 운동성도 만족할 만한 결과를 보였고, 안와삽입물의 노출, 안구 함몰, 상안검고랑변형등의 합병증은 없었다. 결론 : Scleral capping 방법의 안구내용제거술은 공막봉합창에 긴장없이 안구로가 심한 환자에서 적당한 크기의(20 mm 이상) 안와삽입물을 안전하게 삽입할 수 있고, 장점이 많은 효과적인 수술방법으로 생각된다.

Purpose: To introduce a new technique, involving the creation of a circumferential 360°scleral relaxing incision, using an implant as large as 20 mm in diameter, and report on the surgical results in the treatment of severe phthisis bulbi, which are not indicated for classic evisceration. Methods: The medical records of 20 patients with 20 phthisis bulbi who had undergone evisceration and placement, using the scleral capping technique, of porous polyethylene orbital implants as large as 20 mm in diameter between September 2002 and February 2006 were reviewed. For each patient, after evisceration, a circumferential 360° equatorial scleral relaxing incision was made posterior to insertion of 4-recti muscles, and a porous polyethylene orbital implant was implanted. Each circumferential scleral relaxing incision wound was loosely sutured in the mattress fashion, using 5-0 braided polyester (Ethibond). Results: The average of preoperative axial length, obtained using A scan and orbital computed tomography scan, was 16.8 mm. Orbital implants of 20 mm in diameter were implanted in all patients. The average of postoperative follow-up interval was 29.1 months. Orbital implant showed good motility to the satisfaction of all of patients. And the scleral capping technique could prevent complications, such as exposure of orbital implant, enophthalmos, and superior sulcus deformity. Conclusions: Scleral capping technique is safe and useful for evisceration in patients with severe phthisis bulbi. This technique can provide adequate space for the placement of and implant as large as 20 mm in diameter without generating any tension on wound. Consequently, this technique provided cosmesis and prosthesis motiliy, even without the use of a Medor coupling peg, with which patients were satisfied.