• 제목/요약/키워드: normal adhesion

검색결과 250건 처리시간 0.024초

극저온 $CO_2$ 세정공정을 위한 거친표면 위 미세입자의 점착특성 연구 (A Study of Minute Particles' Adhesion on a Rough Surface for a Cryogenic $CO_2$ Cleaning Process)

  • 석종원;이성훈;김필기
    • 반도체디스플레이기술학회지
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    • 제9권1호
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    • pp.5-10
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    • 2010
  • Among a variety of cleaning processes, the cryogenic carbon dioxide ($CO_2$) cleaning has merits because it is highly efficient in removing very fine particles, innoxious to humans and does not produce residuals after the cleaning, which enables us to extend its area of coverage in the semi-conductor fabrication society. However, the cryogenic carbon dioxide cleaning method has some technical research issues in aspect to particles' adhesion and removal. To resolve these issues, performing an analysis for the identification of particle adhesion mechanism is needed. In this study, a research was performed by a theoretical approach. To this end, we extended the G-T (Greenwood-Tripp) model by applying the JKR (Johnson-Kendall-Roberts) and Lennard-Jones potential theories and the statistical characteristics of rough surface to investigate and identify the contact, adhesion and deformation mechanisms of soft or hard particles on the rough substrate. The statistical characteristics of the rough surface were taken into account through the employment of the normal probability distribution function of the asperity peaks on the substrate surface. The effects of surface roughness on the pull-off force for these particles were examined and discussed.

족삼리(足三里) 진구약침이 생쥐의 Collagen-induced Arthritis에 미치는 영향(影饗) (A Study on the Effect of Herbal-acupuncture with Gentianae macrophyllase Radix Solution at Joksamni(ST36) on Collagen-induced Arthritis DBA/1J mice)

  • 박정현;임윤경;이현
    • Korean Journal of Acupuncture
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    • 제24권3호
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    • pp.117-137
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    • 2007
  • Objectives & Methods : The purpose of this study is to observe the effects of Gentianae macrophyllase Radix herbal-acupuncture solution(GR-HAS) at Joksamni(ST36) on Collagen-induced arthritis(CIA) in DBA/1J mice. The author performed several experimental items to analyze arthritis evaluation, change of weight, spleen size and adhesion rate, change of cytokine level, IgG, IgM and anti-collagen II , change of immunocyte count, histological change of CIA mouse joint related with RA. Results : 1. In the GR-HA group, the arthritis index, the incidence of arthritis and joint edema were significantly decreased. 2. In GR-HA group, there were no weight loss and similarly maintained as normal group. Spleen size, adhesion rate and the edema and transformation of knee joint were low and similarly maintained as normal group. 3. In the GR-HA, cytokine level, IgG, IgM and anti-collagen II were significantly decreased. 4. In the GR-HA, the change of immunocyte count were similarly maintained as normal group. 5. In the histological changes of the CIA mouse joint, the cartilage destruction and synovial cell proliferation were decreased in the GR-HA(Hematoxylin and eosin stain). The collagen fiber expressions in the GR-HA were similar with that of the normal group(Masson's Trichrome stain) Conclusions : These results suggest that GR-HA at ST36 has an effect to control immune reaction and suppress inflammation, synovial cell proliferation and cartilage destruction in rheumatoid arthritis.

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천골열공을 통하여 삽입된 Flexible Fiberoptic Epiduroscope을 이용한 신경근병증 환자의 치험 -증례 보고- (Treatment of Radiculopathy with Flexible Fiberoptic Epiduroscope Inserted through the Sacral Canal -A case report-)

  • 박종완;이정순;이주철;김용익;황경호;박욱
    • The Korean Journal of Pain
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    • 제10권2호
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    • pp.270-273
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    • 1997
  • Caudal epiduroscopy has been introduced as an alternative technique for direct injection of epidural steroid and lysis of adhesion. Futher, it gives a better understanding of the role of epidural adhesion in recurrence of sciatica and low back disorder after surgery. We experienced a clinical application of flexible fiberoptic epiduroscope inserted through the sacral canal. A 37-year-old woman was suffering from right lumbar radiculopathy after an operation for a herniated disc. A series of volumetric caudal steroid injections and physical therapy had little effect on her symptoms. Patient was thought to be a good candidate for epiduroscopy. Flexible flberoptic epiduroscopy was as follows: 60 ml of normal saline irrigation and epidurogram, 40 mg of triamcinolone in 10m1 of normal saline was directed around right L5 nerve root. The following morning, patient reported reduced pain in her leg.

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CD30-Mediated Regulation of Cell Adhesion Molecule Expression on Murine T Cells

  • Nam, Sang-Yun
    • IMMUNE NETWORK
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    • 제3권1호
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    • pp.8-15
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    • 2003
  • Background: CD30 is a member of TNF receptor family and expressed on lymphocytes and other hematopoietic cells following activation as well as Hodgkin and Reed-Sternberg cells in Hodgkin's lymphoma. In this study, CD30-mediated regulation of cell adhesion molecule expression on normal activated mouse T cells was investigated. Methods: Mouse T cells were activated with anti-CD3 antibody for induction of CD30, which was cross-linked by immobilized anti-CD30 antibody. Results: High level of CD30 expression on T cells was observed on day 5, but only little on day 3 even under culture condition resulting in an identical T cell proliferation, indicating that CD30 expression requires a prolonged stimulation up to 5 days. Cross-linking of CD30 alone altered neither proliferation nor apoptosis of normal activated T cells. Instead, CD30 appeared to promote cell adherence to culture substrate, and considerably upregulated ICAM-1 and, to a lesser extent, ICAM-2 expression on activated T cells, whereas CD2 and CD18 (LFA-1) expression was not affected. None of cytokines known as main regulators of ICAM-1 expression on tissue cells (IL 4, $IFN{\gamma}$ and $IFN{\alpha}$) enhanced ICAM-1 expression in the absence of CD30 signals. On the other hand, addition of $NF-{\kappa}B$ inhibitor, PDTC (0.1 mM) completely abrogated the CD30-mediated upregulation of ICAM-1 expression, but not CD2 and ICAM-2 expression. Conclusion: This results support that CD30 upregulates ICAM-1 expression of T cell and such regulation is not mediated by higher cytokine production but $NF-{\kappa}B$ activation. Therefore, CD30 may play important roles in T-T or T-B cell interaction through regulation of ICAM-1, and -2 expression.

The High Expressed Serum Soluble Neural Cell Adhesion Molecule, a High Risk Factor Indicating Hepatic Encephalopathy in Hepatocelular Carcinoma Patients

  • Liu, Tian-Hua;Guo, Kun;Liu, Ri-Qiang;Zhang, Shu;Huang, Zhuo-Hui;Liu, Yin-Kun
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권8호
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    • pp.3131-3135
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    • 2015
  • Objective: To investigate whether the expression of serum soluble neural cell adhesion molecule (sNCAM) is associated with hepatic encephalopathy (HE) in hepatocelular carcinoma (HCC) patients. Materials and Methods: The Oncomine Cancer Microarray database was used to determine the clinical relevance of NCAM expression in different kinds of human cancers. Sera from 75 HCC cases enrolled in this study were assessed for expression of sNCAM by enzyme linked immunosorbent assay (ELISA). Results: Dependent on the Oncomine Cancer Microarray database analysis, NCAM was down regulated in 10 different kinds of cancer, like bladder cancer, brain and central nervous system cancer, while up-regulated in lung cancer, uterine corpus leiomyoma and sarcoma, compared to normal groups. Puzzlingly, NCAM expression demonstrated no significant difference between normal and HCC groups. However, we found by quantitative ELISA that the level of sNCAM in sera from HCC patients with HE ($347.4{\pm}151.9ng/ml$) was significantly more up-regulated than that in HCC patients without HE ($260.3{\pm}104.2ng/ml$), the p-value being 0.008. sNCAM may be an important risk factor of HE in HCC patients, the correlation coefficients was 0.278 (P<0.05) on rank correlation analysis. Conclusions: This study highlights that up-regulated level of serum sNCAM is associated with HE in HCC patients and suggests that the high expression can be used as an indicator.

Bracket bonding to polymethylmethacrylate-based materials for computer-aided design/manufacture of temporary restorations: Influence of mechanical treatment and chemical treatment with universal adhesives

  • Goracci, Cecilia;Ozcan, Mutlu;Franchi, Lorenzo;Di Bello, Giuseppe;Louca, Chris;Vichi, Alessandro
    • 대한치과교정학회지
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    • 제49권6호
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    • pp.404-412
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    • 2019
  • Objective: To assess shear bond strength and failure mode (Adhesive Remnant Index, ARI) of orthodontic brackets bonded to polymethylmethacrylate (PMMA) blocks for computer-aided design/manufacture (CAD/CAM) fabrication of temporary restorations, following substrate chemical or mechanical treatment. Methods: Two types of PMMA blocks were tested: $CAD-Temp^{(R)}$ (VITA) and $Telio^{(R)}$ CAD (Ivoclar-Vivadent). The substrate was roughened with 320-grit sandpaper, simulating a fine-grit diamond bur. Two universal adhesives, Scotchbond Universal Adhesive (SU) and Assure Plus (AP), and a conventional adhesive, Transbond XT Primer (XTP; control), were used in combination with Transbond XT Paste to bond the brackets. Six experimental groups were formed: (1) $CAD-Temp^{(R)}/SU$; (2) $CAD-Temp^{(R)}/AP$; (3) $CAD-Temp^{(R)}/XTP$; (4) $Telio^{(R)}$ CAD/SU; (5) $Telio^{(R)}$ CAD/AP; (6) $Telio^{(R)}$ CAD/XTP. Shear bond strength and ARI were assessed. On 1 extra block for each PMMA-based material surfaces were roughened with 180-grit sandpaper, simulating a normal/medium-grit ($100{\mu}m$) diamond bur, and brackets were bonded. Shear bond strengths and ARI scores were compared with those of groups 3, 6. Results: On $CAD-Temp^{(R)}$ significantly higher bracket bond strengths than on $Telio^{(R)}$ CAD were recorded. With XTP significantly lower levels of adhesion were reached than using SU or AP. Roughening with a coarser bur resulted in a significant increase in adhesion. Conclusions: Bracket bonding to CAD/CAM PMMA can be promoted by grinding the substrate with a normal/medium-grit bur or by coating the intact surface with universal adhesives. With appropriate pretreatments, bracket adhesion to CAD/CAM PMMA temporary restorations can be enhanced to clinically satisfactory levels.

Numerical modeling and prediction of adhesion failure of adhesively bonded composite T-Joint structure

  • Panda, Subhransu K;Mishra, Pradeep K;Panda, Subrata K
    • Structural Engineering and Mechanics
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    • 제74권6호
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    • pp.723-735
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    • 2020
  • This study is reported the adhesion failure in adhesive bonded composite and specifically for the T-joint structure. Three-dimensional finite element analysis has been performed using a commercial tool and the necessary outcomes are obtained via an eight noded solid element (Solid 185-element) from the library of ANSYS. The structural analysis input has been incurred through ANSYS parametric design language (APDL) code. The normal and shear stress distributions along different layers of the joint structure have been evaluated as the final outcomes. Based on the stress distributions, failure location in the composite joint structure has been identified by using the Tsai-Wu stress failure criterion. It has been found that the failure index is maximum at the interface between flange and web part of the joint (top layer) which indicates the probable location of failure initiation. This kind of failures are considered as adhesion failure and the failure propagation is governed by strain energy release rate (SERR) of fracture mechanics. The different adhesion failure lengths are also considered at the failure location to calculate the SERR values i.e. mode I fracture (opening), mode II fracture (sliding) and mode III fracture (tearing) along the failure front. Also, virtual crack closure technique (VCCT) principle of fracture mechanics steps is used to calculate the above said SERRs. It is found that the mode I SERR is more dominating compared to other two modes of failure for the joint considered. Finally, the influences of various parametric (geometrical and material) effect on SERR of the joint structure are evaluated and discussed in details.

The effect of two artificial salivas on the adhesion of Candida albicans to heat-polymerized acrylic resin

  • Oncul, Burcin;Karakis, Duygu;Al, Funda Dogruman
    • The Journal of Advanced Prosthodontics
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    • 제7권2호
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    • pp.93-97
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    • 2015
  • PURPOSE. Xerostomia can diminish the quality of life, leads to changes in normal chemical composition of saliva and oral microbiata, and increases the risk for opportunistic infections, such as Candida albicans. Various artificial salivas have been considered for patients with xerostomia. However, the knowledge on the antifungal and antiadhesive activity of artificial saliva substitutes is limited. The aim of the present study was to evaluate influence of two artificial salivas on the adhesion of Candida albicans to the polymethylmethacrylate disc specimens. MATERIALS AND METHODS. Two commercial artificial salivas (Saliva Orthana and Biotene Oral Balance Gel) were selected. 45 polymethylmethacrylate disc specimens were prepared and randomly allocated into 3 groups; Saliva Orthana, Biotene-Oral Balance gel and distilled water. Specimens were stored in the artificial saliva or in the sterile distilled water for 60 minutes at $37^{\circ}C$. Then they were exposed to yeast suspensions including Candida albicans. Yeast cells were counted using ${\times}40$ magnification under a light microscope and data were analysed. RESULTS. Analysis of data indicated statistically significant difference in adhesion of Candida albicans among all experimental groups (P=.000). Findings indicated that Saliva Orthana had higher adhesion scores than the Biotene Oral Balance gel and distilled water (P<.05). CONCLUSION. In comparison of Saliva Orthana, the use of Biotene Oral Balance Gel including lysozyme, lactoferrin and peroxidase may be an appropriate treatment method to prevent of adhesion of Candida albicans and related infections in patients with xerostomia.

Colloidal Probe 원자현미경을 이용한 2차전지 전극용 폴리머 바인더의 응착 및 마찰 특성 평가 (Assessment of Adhesion and Frictional Properties of Polymer Binders for Secondary Cells using Colloidal Probe Atomic Force Microscope)

  • 웬당쾅;정구현
    • Tribology and Lubricants
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    • 제35권3호
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    • pp.169-175
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    • 2019
  • In lithium-ion batteries (LIBs), the stress induced by the volume change of an electrode during charge-discharge processes may often cause the mechanical integrity of the electrode to degrade. Polymer binders with enhanced mechanical properties are preferred for improved mechanical integrity and cycling stability of the electrode. In addition, given that sliding and shearing between the polymer binder and components in the electrode may readily occur, frictional and adhesion characteristics of the polymer binder may play a critical role in the mechanical integrity of the electrode. In this study, frictional and adhesion characteristics of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) were investigated using a colloidal probe atomic force microscope. Friction loops were obtained under various normal forces ranging from 0 to 159 nN in air and electrolyte and then the interfacial shear strengths of PAN and PVDF in air were calculated to be $1.4{\pm}0.5$ and $1.3{\pm}0.3MPa$, respectively. The results show that in electrolyte, interfacial shear strength of PAN decreased slightly ($1.2{\pm}0.2MPa$), whereas that of PVDF decreased drastically ($0.06{\pm}0.01MPa$). Decreases in mechanical properties and adhesion in electrolyte may be responsible for the decrease in interfacial shear strength in electrolyte. The findings from this study may be helpful in developing polymer binders to improve the mechanical integrity of electrodes in LIBs.

Effects of Lift Resistance on Dynamic Load Acting on a Circular Wheel

  • Kishimoto, Tadashi;Taniguchi, Tetsuji;Sakai, Jun;Choe, Jung-Seob;Ohtomo, Koh-Ichi
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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    • pp.1166-1175
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    • 1993
  • The objective of this study is to measure contra-retractive adhesion and lift resistance acting on the rim section of a circular wheel for analyses of their effects on the dynamic load. A circular iron wheel was used for experiments. A part of the wheel rim was cut off, and transducers which can measure normal and tangential forces were installed in this section. Experiments were conducted on a laboratory soil bin which was filled with clayey soil under wet and dry conditions. The mechanism of generating contra -retractive adhesion on a circular wheel were analyzed by the experiments and motion analyses of the wheel. Effects of lift resistance on dynamic load were analyzed by measured forces under wet soil conditions in comparison in comparison with those under dry conditions. The showed that a part of the lift resistance were transferred to the dynamic load. These results may become basic data and ideas for analyses of tractor dynamic under wet soil conditions.

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