• Title/Summary/Keyword: adhesion model

Search Result 293, Processing Time 0.033 seconds

Effects of βig-h3/Chitosan Dressing on Dermal Fibroblast and Wound Healing (βig-h3포함 키토산 상처 도포제의 섬유아세포 증식 및 상처치유 개선 능 평가)

  • Cho, Ae-Ri;Choi, Hee-Sun
    • Journal of Pharmaceutical Investigation
    • /
    • v.39 no.1
    • /
    • pp.51-54
    • /
    • 2009
  • ${\beta}ig$-h3, is a TGF-${\beta}$-induced gene product, extracellular matrix protein with 68 kDa MW(683 amino acids) and has been known for its possible roles in cell adhesion, spreading, migration and proliferation. To minimize a proteolytic degradation of ${\beta}ig$-h3, ${\beta}ig$-h3 incorporated chitosan sponge was prepared and its effects on fibroblast adhesion and migration were investigated. And its wound healing efficacy was evaluated in deep 2nd degree burn rabbit ear wound model. ${\beta}ig$-h3 enhanced fibroblast adhesion and proliferation. In histological observation, a significant over-proliferation of epidermal regeneration was observed in ${\beta}ig$-h3/chitosan dressing applied wound while epidermal regeneration was not proceeded yet in chitosan only treated wound. ${\beta}ig$-h3/sponge dressing could enhance epidermal regeneration.

Detergency of Particulate Soil in Anion/Nonionic Surfactant Mixed Solution (음이온/비이온 혼합 계면활성제 용액에서의 고형오구의 세척성)

  • Kang, In-Sook
    • Fashion & Textile Research Journal
    • /
    • v.13 no.5
    • /
    • pp.790-796
    • /
    • 2011
  • This study was designed to investigate the influence of ratio of anionic/nonionic surfactant mixture on detergency of particulate soil under various solutions. The detergency of the particulate soil was determined by adhesion of particle to fabric and its removal from fabric separately. The PET fabric and ${\alpha}-Fe_2O_3$were used as materials of textile and model of particulate soil, respectively. The detergency was investigated as a function of surfactants concentration, ionic strength, kinds of electrolyte and mole numbers of oxyethylene ether of nonionic surfactant in different ratio of anionic/nonionic surfactant mixture. Although some deviations exist, the adhesion of particle to fabric generally increased with decreasing its removal from fabric. The detergency of particulate soil on PET fabric was relatively higher in anionic/nonionic surfactant mixed solution than in each single surfactant solution, but the influence of ratio of anionic/nonionic surfactant mixture on detergency of particulate soil was low. Generally the detergency of particulate soil on fabric was at its maximum at 0.1% surfactant concentration, $1{\times}10^{-3}$ ionic strength, $Na_5P_3O_{10}$ electrolytes and 10 mole numbers of oxyethylene ether of nonionic surfactant, regardless of ratio of anionic/nonionic surfactant mixture.

Variable Parameter Sliding Controller Design for Vehicle Brake with Wheel Slip

  • Liang, Hong;Chong, Kil-To
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.11
    • /
    • pp.1801-1812
    • /
    • 2006
  • In this paper, a 4-wheel vehicle model including the effects of tire slip was considered, along with variable parameter sliding control, pushrod force as the end control parameter, and an antilock sliding control, in order to improve the performance of the vehicle longitudinal response. The variable sliding parameter is made to be proportional to the square root of the pressure derivative at the wheel, in order to compensate for large pressure changes in the brake cylinder. A typical tire force-relative slip curve for dry road conditions was used to generate an analytical tire force-relative slip function, and an antilock sliding control process based on the analytical tire force-relative slip function was used. A retrofitted brake system, with the pushrod force as the end control parameter, was employed, and an average decay function was used to suppress the simulation oscillations. Simulation results indicate that the velocity and spacing errors were slightly larger than the results that without considering wheel slip effect, the spacing errors of the lead and follower were insensitive to the adhesion coefficient up to the critical wheel slip value, and the limit for the antilock control on non-constant adhesion road condition was determined by the minimum of the equivalent adhesion coefficient.

P-Selectin-mediated Acute Inflammation Can Be Blocked by Chemically Modified Heparin, RO-Heparin

  • Gao, Yanguang;Li, Na;Fei, Rui;Chen, Zhihong;Zheng, Sheng;Zeng, Xianlu
    • Molecules and Cells
    • /
    • v.19 no.3
    • /
    • pp.350-355
    • /
    • 2005
  • Selectins are carbohydrate-binding cell adhesion molecules that play a major role in the initiation of inflammatory responses. Heparin can bind to P-selectin, and its anti-inflammatory property is mainly due to inhibition of P-selectin. However, the strong anticoagulant activity of heparin limits its clinical use. We prepared periodate-oxidized, borohydride-reduced heparin (RO-heparin) by chemical modification and tested its anticoagulant and anti-inflammatory activities. Activated partial thromboplastin time (aPTT) assays showed that, compared with heparin, RO-heparin had greatly reduced anticoagulant activity. Intravenous administration of this compound led to reduction in the peritoneal infiltration of neutrophils in a mouse acute inflammation model. In vitro cell adhesion experiments demonstrated that the effect of RO-heparin on inflammatory responses was mainly due to inhibiting the interaction of P-selectin with its ligands. These results indicate that RO-heparin may be a safer treatment for inflammation than heparin, especially when selectin is targeted.

Study on Chucking Force and Substrate Deformation Characteristics of Electrostatic Chuck for Deposition According to Substrate Sizes (증착용 정전척의 기판 크기에 따른 척킹력 및 기판 변형 특성 연구)

  • Seong Bin Kim;Dong Kyun Min
    • Journal of the Semiconductor & Display Technology
    • /
    • v.23 no.2
    • /
    • pp.12-18
    • /
    • 2024
  • A Electrostatic chuck is a device that fixes the substrate, using the force between charges applied between two parallel plates to attract substrates such as wafers or OLED panels. Unlike mechanical suction methods, which rely on physical fixation, this method utilizes the force of electrostatics for fixation, making it important to verify the adhesion force. As the size of the substrate increases, deformations due to gravity or chucking force also increase, and the adhesion force decreases rapidly as the distance between the chuck and the substrate increases. The outlook for displays is shifting from small to large OLEDs, necessitating consideration of substrate deformations. In this paper, to confirm the deformation of the substrate through various patterns, a simplified 2D model using Ansys' electromagnetic field analysis program, Maxwell, and the static structural analysis program, Mechanical, was utilized to observe changes in adhesion force according to the variation in the air gap between the substrate and the chuck. Additionally, the chucking force was analyzed for the size of the substrate, and the deformation of the substrate was confirmed when gravity and chucking force act simultaneously.

  • PDF

Analysis on Forces Acting on the Contact Lens Fitted on the Cornea (콘택트 렌즈에 작용하는 힘의 해석)

  • Kim, Dae-Soo
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.7 no.2
    • /
    • pp.1-11
    • /
    • 2002
  • A mathematical model is proposed to analyze the force; acting on the hard contact lens fitted on the cornea. The model incorporates the nonlinear equations and their numerical solution program, based on the formulations of surface tension force arising from the capillary action in the tear-film layer between the lens and cornea. The model simulates how the adhesion between lens and cornea varies according to the base curves and diameters of the lenses. When the spherical lens is fitted on the spherical cornea it is to rotate downward due to the weight of lens itself until it reaches an equilibrium position along the cornea where the counter(upward) moment caused by net force between the upper and lower portion of the periphery of lens. It is found that both the adhesion and displacement of lens along the cornea, where the gravity of lens balances the capillary-induced upward force, increases rapidly as the base curve of lens increases, i.e., as the lens gets flatter, while the increase in the diameter of lenses has resulted in the less increase in the rotation and adhesion. With the base curve and diameters of lenses being remained constant the increase in surface tension of tear film yields the increase in the adhesion between the cornea and lens while the initial rotation of lens is inversely proportional to the surface tension of the tear film.

  • PDF

The Effect of Particle Size on the Detergency of Particulate Soil (고형오구 입자크기가 고형오구의 세척성에 미치는 영향)

  • Mun, Mi-Hwa;Kang, In-Sook
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.34 no.4
    • /
    • pp.653-662
    • /
    • 2010
  • This study investigates the effect of particle size on the detergency of particulate soil using an $\alpha-Fe_2O_3$ particle as the model. Monodispersed spherical $\alpha-Fe_2O_3$ particles were prepared by the hydrothermal aging of an acidic $FeCl_3$ and HCl solution. The $\xi$-potential of PET fiber was measured by the streaming potential method. The potential energy of interaction between the particle and fiber was calculated using the heterocoagulation theory for a sphere-plate model. The $\xi$-potential of PET fiber and potential energy of interaction between particles and fiber increased with a decreasing particle size in a DBS solution. However, in the nonionic surfactant solution, the $\xi$-potential signs of PET fiber and $\alpha-Fe_2O_3$ particles were (-) and (+), respectively; there was no repulsive power between the particles and substrate. The adhesion of particles to the fabric increased with increasing particle size in the anionic surfactant solution and their removal from the fabric increased with a decreasing particle size. The adhesion of particles to the fabric and their removal from the fabric was biphasic with a maximum and minimum at 0.1% concentration of the surfactant solution. In the nonionic surfactant solution the adhesion of particles to fabric and their removal from the fabric were greater than the ones in the anionic surfactant DBS solution.

An in vitro model of Fusobacterium nucleatum and Porphyromonas gingivalis in single- and dual-species biofilms

  • Tavares, Livia Jacovassi;Klein, Marlise Inez;Panariello, Beatriz Helena Dias;de Avila, Erica Dorigatti;Pavarina, Ana Claudia
    • Journal of Periodontal and Implant Science
    • /
    • v.48 no.1
    • /
    • pp.12-21
    • /
    • 2018
  • Purpose: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. Methods: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy. Results: The data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation. Conclusions: Polystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.

Inhibitory Effect of Berberine on TNF-$\alpha$-induced U937 Monocytic Cell Adhesion to HT29 Human Colon Epithelial Cells is Mediated through NF-$\kappa$B Rather than PPAR$\gamma$ (TNF-$\alpha$ 자극에 의한 U937 단핵구 세포의 HT29 대장 상피 세포 부착에 대한 Berberine의 PPAR$\gamma$가 아닌 NF-$\kappa$B 경로를 통한 억제 효과)

  • Park, Su-Young;Lee, Gwang-Ik;Kim, Il-Yeob;Kim, Jung-Ae
    • YAKHAK HOEJI
    • /
    • v.54 no.2
    • /
    • pp.91-96
    • /
    • 2010
  • Berberine, an isoquinoline alkaloid, has a wide range of pharmacological effects, including anti-inflammation. It has been reported that berberine inhibits experimental colitis through inhibition of IL-8, and that inhibitory effect of berberine on inflammatory cytokine expression is mediated through peroxisome proliferator activated receptor (PPAR)-$\gamma$. In this study, we examined the effects and action mechanism of berberine on the tumor necrosis factor (TNF)-$\alpha$-induced monocyte adhesion to HT29 human colonic epithelial cells, which is commonly used as an in vitro model of inflammatory bowel disease (IBD). Berberine significantly inhibited the TNF-$\alpha$-induced monocyte adhesion to HT29, which is similar to the effect of PDTC, a nuclear factor (NF)-$\kappa$B inhibitor. However, ciglitazone and GW, the ligands of PPAR-$\gamma$, did not suppress the TNF-$\alpha$-induced monocyte adhesion to HT29 cells. In addition, TNF-$\alpha$-induced chemokine expression and NF-$\kappa$B transcriptional activity were significantly inhibited by berberine in a concentration-dependent manner. The results suggest that inhibitory effect of berberine on colitis is mediated through suppression of NF-$\kappa$B and NF-$\kappa$B-dependent chemokine expression.

Representation of Curl Exaggeration, Cohesion, Adhesion and Stiffness in Wet Curly Hair

  • Jong-Hyun Kim
    • Journal of the Korea Society of Computer and Information
    • /
    • v.28 no.10
    • /
    • pp.77-84
    • /
    • 2023
  • Simulating the cohesion and stiffness of wet hair or fur in physics-based simulations is one of the most challenging problems. Wet hair or fur is characterized by bunching and stiffening at the ends, a phenomenon that can be seen in wet animal fur or hair. In addition, when wet hair interacts with a solid, adhesion occurs, but this problem becomes difficult to solve due to the different distribution and balance of forces in curly hair. In traditional methods, wet hair is represented by hand or by using static hairstyles to represent wet curls and hair. However, how to depict the details of wet curly hair has not been actively researched. In this paper, we propose a new algorithm to efficiently model the curl exaggeration, cohesion, adhesion, and stiffness of wet curly hair. The proposed method efficiently simulates cohesion and integrates stiffness constraints with curl dynamics to reliably control hair elasticity.