• Child Health Nursing Research
• /
• v.15 no.4
• /
• pp.335-342
• /
• 2009

Purpose: This study, using a pre-post test design of non-equivalence comparative group, was done to determine effects of Kangaroo care (KC) on growth in premature infants and on maternal attachment (MA). Methods: Fifty-three premature infants were assigned to the KC (24) or control group (CG) (29). Data were collected from July 2007 to June 2008. KC was given for 60 min at a time, Monday, Wednesday, and Friday for 10 times. Weight, height, and head circumference (HC) of premature infants were checked before the program started. Following the initial measurement, the program was given and measurements were taken again at the end of the program. For measurement of attachment between mother and infant, data collection was done using structured self-reported questionnaires. Results: KC group had a higher weight (t=2.565, p=.013), height (t=2.182, p=.034) and HC (t=2.468, p=.017) than the CG. Compared to the CG, the KC had significantly higher scores in MA (t=2.026, p=.048). Conclusion: The results of this study suggest that the practice of KC in the nursing environment might actively promote attachment between mother and infant as well as acceleration of growth for premature infants as one of the most efficient nursing intervention.

• Journal of Technologic Dentistry
• /
• v.45 no.3
• /
• pp.61-66
• /
• 2023

Purpose: The current study examined the retention and wear resistance of stud-type attachments made of high-performance polyetheretherketone (PEEK) or polyetherketoneketone (PEKK) from the polyaryletherketones (PAEKs) family. Methods: The study sample included 10 PEEK or PEKK attachments that were mounted onto their male parts, designed on the upper aspect of the attachment, with a load of 30 N. Tensile stress was applied using an Instron machine to separate the male and female parts, and the maximum tensile stress to be applied was determined based on the retention force observed. The wear resistances of PEEK and PEKK were evaluated by measuring the inner diameter of the inserted female part 10 times. Results: The maximum tensile stresses of PEEK and PEKK were 56.26±0.58 and 69.12±0.92 N, respectively, with the maximum stress required to remove the PEKK specimens from the abutment being 12.86 N higher than that required to remove the PEEK specimens. Furthermore, PEKK exhibited higher wear resistance than PEEK. Conclusion: This study evaluated custom-made removable implant-retained attachment components for overdentures, wherein the female parts were made of PEEK or PEKK. The retention stress and wear resistance were evaluated based on the type of attachment material, and the results showed that both types of attachment inserts demonstrated clinically acceptable results in terms of retention.

• Journal of Environmental Science International
• /
• v.11 no.4
• /
• pp.327-332
• /
• 2002

Optical microscope, SEM (Scanning Electron Microscopy) and fluorescent microscope were used for qualitative and morphological studies of the attached biomass on PE (polyethylene) substratum under anaerobic condition. It was shown by the observation of optical microscope that the initial attachment of biomass began in crevices of the surface of PE. The shape and structure of the attached biofilm could be observed by SEM photographs, but species of bacteria were and methanogens were not classified. A large number of methanogenic bacteria were identified on the surface of PE substratum by fluorescence under 480nm of radiation. It was estimated that methanogenic bacteria was also related to initial attachment of biomass under anaerobic condition.

• Journal of Periodontal and Implant Science
• /
• v.33 no.2
• /
• pp.225-246
• /
• 2003

Recent study on the enamel matrix derivatives explained on the effects of new bone and new attachment formation in infrabony pocket of periodontal defects. The purpose of this study was to investigate on the biological effects of enamel matrix derivatives to attachment, proliferation and activation of periodontal ligament and osteoblast cells, After treatment of osteoblast and PDL cells with various Emdogain concentration level(0.03${\mu}g$/ml, 3${\mu}g$/ml, 300${\mu}g$/ml), activation of osteogenetic factor, calcified nodule formation and measuring alkaline phosphatase activity(ALP) were performed. 1. Both osteoblast and PDL cell showed increasing initial cell attachment with 300${\mu}g$/ml Emdogain concentration. 2. At the level of 300${\mu}g$/ml, accelerated proliferation of oseoblast and PDL cell was appeared. 3. As Emdogain's concentration increased, increased ALP activation of osteoblast was shown. In case of PDL cell, Emdogain increased ALP activation prominently at the level of 300${\mu}g$/ml. 4. No statistically significant activating change were founded at all of the concentrations of Emdogain on the activating of transcript factor Runx2 for differentiating osteoblast. 5. At the level of 300${\mu}g$/ml, calcified nodule formation was increased prominently to compare with other concentration. These results indicated that Emdogain should activate initial attachment, proliferation and activation, but not on Runx2 activation and can be used for useful tool of the treatment of periodontal tissue regeneration.

• Biomaterials and Biomechanics in Bioengineering
• /
• v.2 no.3
• /
• pp.143-157
• /
• 2015

Successful integration of cementless femoral stems using porous surfaces relies on effective periimplant bone healing to secure the bone-implant interface. The initial stages of the healing process involve protein adsorption, fibrin clot formation and cell osteoconduction onto the implant surface. Modelling this process in vitro, the current work considered the effect of fibrin deposition on the responses of human mesenchymal stromal cells cultured on ferritic fibre networks intended for magneto-mechanical actuation of in-growing bone tissue. The underlying hypothesis for the study was that fibrin deposition would support early stromal cell attachment and physiological functions within the optimal regions for strain transmission to the cells in the fibre networks. Highly porous fibre networks composed of 444 ferritic stainless steel were selected due to their ability to support human osteoblasts and mesenchymal stromal cells without inducing untoward inflammatory responses in vitro. Cell attachment, proliferation, metabolic activity, differentiation and penetration into the ferritic fibre networks were examined for one week. For all fibrin-containing samples, cells were observed on and between the metal fibres, supported by the deposited fibrin, while cells on fibrin-free fibre networks (control surface) attached only onto fibre surfaces and junctions. Initial cell attachment, measured by analysis of deoxyribonucleic acid, increased significantly with increasing fibrinogen concentration within the physiological range. Despite higher cell numbers on fibrin-containing samples, similar metabolic activities to control surfaces were observed, which significantly increased for all samples over the duration of the study. It is concluded that fibrin deposition can support the early attachment of viable mesenchymal stromal cells within the inter-fibre spaces of fibre networks intended for magneto-mechanical strain transduction to in-growing cells.

• The Journal of Advanced Prosthodontics
• /
• v.3 no.2
• /
• pp.63-68
• /
• 2011

PURPOSE. The object of this study was to investigate the effect of UV irradiation (by a general commercial UV sterilizer) on anodized titanium surface. Surface characteristics and cellular responses were compared between anodized titanium discs and UV irradiated anodized titanium discs. MATERIALS AND METHODS. Titanium discs were anodized and divided into the following groups: Group 1, anodized (control), and Goup 2, anodized and UV irradiated for 24 hours. The surface characteristics including contact angle, roughness, phase of oxide layer, and chemical elemental composition were inspected. The osteoblast-like human osteogenic sarcoma (HOS) cells were cultured on control and test group discs. Initial cellular attachment, MTS-based cell proliferation assay, and ALP synthesis level were compared between the two groups for the evaluation of cellular response. RESULTS. After UV irradiation, the contact angle decreased significantly (P<.001). The surface roughness and phase of oxide layer did not show definite changes, but carbon showed a considerable decrease after UV irradiation. Initial cell attachment was increased in test group (P=.004). Cells cultured on test group samples proliferated more actively (P=.009 at day 2, 5, and 7) and the ALP synthesis also increased in cells cultured on the test group (P=.016 at day 3, P=.009 at day 7 and 14). CONCLUSION. UV irradiation induced enhanced wettability, and increased initial cellular responses of HOS cells on anodized titanium surface.

• Korean Journal of Metals and Materials
• /
• v.50 no.4
• /
• pp.338-343
• /
• 2012

The early osseointegration of titanium (Ti) dental implants is related to the initial cell morphology. The morphology of the cells (mesenchymal stem cells, MSC) was observed on three different Ti disc surfaces, which were mechanically treated by polishing, blasting, and scratching. A non-directional surface (isotropic texture) was obtained by the blasting of HA grits on cp-Ti discs, and a unidirectional surface (anisotropic texture) was obtained by the scratching of SiC papers. The cell attachment and arrangement in the initial periods were quite similar, but those in the later periods were significantly affected by the texture of the cp-Ti discs. After 1 week, the blasted Ti discs showed non-directional arrangement or spreading of the cells, whereas the scratched cp-Ti discs showed unidirectional properties parallel to the direction of the scratched grooves on the surface. The surface roughness of the cp-Ti discs significantly affects cell proliferation. Cell proliferation on the blasted and scratched surfaces was about 60% and 40% higher compared to the control result (polishing group) after 1 week (P<0.05). Cell proliferation on the blasted and scratched surfaces after 1 week was slightly enhanced with increasing surface roughness. It is believed that the direction of cell attachment and arrangement is closely related to the surface texture of the substrate surfaces, but cell proliferation after a relatively long period of time is directly enhanced by the surface roughness, not by the surface texture.

• The Journal of Advanced Prosthodontics
• /
• v.14 no.1
• /
• pp.12-21
• /
• 2022

PURPOSE. The purpose of this study was to investigate changes in retention and wear pattern of Locator^® and ADD-TOC attachments on a digital milled bar by performing chewing simulation and repeated insertion/removal of prostheses in fully edentulous models. MATERIALS AND METHODS. Locator (Locator^®; Zest Anchors Inc., Escondido, CA, USA) was selected as the control group and ADD-TOC (ADD-TOC; PNUAdd Co., Ltd., Busan, Republic of Korea) as the experimental group. A CAD-CAM milled bar was mounted on a master model and 3 threaded holes for connecting a bar attachment was formed using a tap. Locator and ADD-TOC attachments were then attached to the milled bar. Simulated mastication and repeated insertion/removal were performed over 400,000 cyclic loadings and 1,080 insertions/removals, respectively. Wear patterns on deformed attachment were investigated by field emission scanning electron microscopy. RESULTS. For the ADD-TOC attachments, chewing simulation and repeated insertion/removal resulted in a mean initial retentive force of 24.43 ± 4.89 N, which were significantly lower than that of the Locator attachment, 34.33 ± 8.25 N (P < .05). Amounts of retention loss relative to baseline for the Locator and ADD-TOC attachments were 21.74 ± 7.07 and 8.98 ± 5.76 N (P < .05). CONCLUSION. CAD-CAM milled bar with the ADD-TOC attachment had a lower initial retentive force than the Locator attachment. However, the ADD-TOC attachment might be suitable for long-term use as it showed less deformation and had a higher retentive force after simulated mastication and insertion/removal repetitions.

• Journal of Environmental Health Sciences
• /
• v.22 no.1
• /
• pp.82-90
• /
• 1996

The objectives of this study were to examine the start-up method and characteristics of biomass attachment on the media in an anaerobic fluidized bed reactor(AFBR). The media adopted was the granular activated carbon which was successfully capable of adsorbing organics and biomass. The reactor was operated at 5 kg $COD/m^3\cdot day$ and 24hr of HRT. There were important problems in the AFBR's start-up, which has been reported very long and unstable. Therefore, this research was to solve the problem of the start-up and it was performed, comparing two start-up ways that were initial fluidized system and initial static-fluidized system. The results were summarized as follows: (1) On the whole initial static-fluidized system was superior to initial fluidized system in the aspects of biogas production rate, methane content and COD removal efficiency etc. (2) At the steady state methane production rate and recoverable bioenergy of initial static-fluidized system were $2.074 m^3CH_4/m^3\cdot day$, $0.488 m^3CH_4/kgCOD_{removed}\cdot day$, and 81.3kcal/day, respectively. (3) Thickness of biofilm was about $5.11 \mu m$, $\rho_{bw}$ and $\rho_{bd}$ were $1.022 g/cm^3, 0.0953g/cm^3$ respectively. (4) Biomass concentration of fluidized state was about 35 mg/g GAC. In conclusion the efficient method on the start-up of the AFBR using GAC as media was initial static-fluidized system and the period of static state needed to reach steady state was considered about twenty days.

• The Journal of Korean Academy of Prosthodontics
• /
• v.59 no.2
• /
• pp.173-180
• /
• 2021

Purpose: The purpose of this study was to evaluate the retentive characteristics of the additional attachments used with implant bar attachment under repeated insertion/removal cycles. Materials and methods: The newly developed attachment and the commercially available attachment were investigated: ADD-Lock (AL), Locator blue (LB). Two fixtures were placed parallel to each other on the custom lower mounting, and patrix of each attachment was fixed to the fixture. Also, the matrix of each attachment was placed on the opposing upper mounting. A universal testing machine was used to measure the retentive force during initial, 100, 250, 500, 1000, 2000, and 2500 repeated insertion/removal cycles. Wear and deformation of the attachment s were observed by scanning electron microscopy (SEM). Mann-Whitney U test (α=.05) and wilcoxon signed-rank test (α=.05) were performed to compare retentive force between each group and before and after 2500 repeated insertion/removal cycles. Results: In terms of initial retentive force and retentive force after 2500 repeated insertion/removal cycles, the AL group (15.24 ± 1.46 N and 9.74 ± 1.16 N) showed significantly smaller values than the LB group (43.53 ± 12.39 N and 22.99 ± 4.77 N) (P<.05). Also, in the loss of retentive force, the AL group (5.50 ± 1.08 N, 36.08%) showed a smaller value than the LB group (20.54 ± 11.89 N, 47.19%) (P<.05). Based on SEM analysis, The AL group showed noticeable wear and deformation in the patrix and the LB group in the matrix. Conclusion: Locator showed a higher initial retentive force than newly developed attachment, while the loss of retentive force was also higher. Both additional attachments are considered to have sufficient retentive force after repeated insertion/removal cycles.