• Journal of Microbiology and Biotechnology
• /
• 제20권1호
• /
• pp.224-228
• /
• 2010

The encapsulation of bacteria may be used to harness them for longer periods of time in order to make them viable, whereas antibiotic treatment would result in controlled release of therapeutic molecules. Encapsulated Escherichia coli GFP (green fluorescent protein) (E. coli GFP) was used here as a model for therapeutic substance - GFP fragments release (model of bioactive substances). Our aim was to evaluate the performance of bacteria encapsulated in hollow fibers (HFs) treated with antibiotic for induction of cell death. The polypropylene-surface-modified HFs were applied for E. coli encapsulation. The encapsulated bacteria were treated with tetracycline in vitro or in vivo during subcutaneous implantation into mice. The HF content was evaluated in a flow cytometer, to assess the bacteria cell membrane permeability changes induced by tetracycline treatment. It was observed that the applied membranes prevented release of bacteria through the HF wall. The E. coli GFP culture encapsulated in HF in vitro proved the tetracycline impact on bacteria viability and allows the recognition of the sequence of events within the process of bacteria death. Treatment of the SCID mice with tetracycline for 8 h proved the tetracycline impact on bacteria viability in vivo, raising the necrotic bacteria-releasing GFP fragments. It was concluded that the bacteria may be safely enclosed within the HF at the site of implantation, and when the animal is treated with antibiotic, bacteria may act as a local source of fragments of proteins expressed in the bacteria, a hypothetical bioactive factor for the host eukaryotic organism.

• Steel and Composite Structures
• /
• 제32권5호
• /
• pp.559-569
• /
• 2019

The bond strength between composite laminates and concrete is a key factor that controls the behavior of concrete members strengthened with fiber reinforced polymer (FRP) sheets, which can be affected by several parameters such as thermal stresses and surface preparation. This article presents the result of an experimental study on the bond strength between FRP sheets and concrete at ambient temperature after specimens had been exposed to elevated temperatures of up to $200^{\circ}C$. For this purpose, 30 specimens of plain concrete with dimensions of $150{\times}150{\times}350mm$ were prepared. Three different conventional surface preparation methods (sandblasting, wire brushing and hole drilling) were considered and compared with a new efficient method (fiber implantation). Deformation field during each experiment was monitored using particle image velocimetry. The results showed that, the specimens which were prepared by conventional surface preparation methods, preserved their bond integrity when exposed to temperature below glass transition temperature of epoxy resin (about $60^{\circ}C$). Beyond this temperature, the bond strength and stiffness decreased significantly (about 50%) in comparison with control specimens. However, the specimens prepared by the proposed method displayed higher bond strengths of up to 32% and 90% at $25^{\circ}C$ and $200^{\circ}C$, respectively.

• 대한임상검사과학회지
• /
• 제37권1호
• /
• pp.35-40
• /
• 2005

This paper reports the morphological nature of the remodelled interface process between implants and surrounding bone after 1, 4, 6, 8 and 12 weeks of implantation of smooth machined implants into rat tibias. After 4 weeks of implantation, histochemical analysis showed that the new bone was growing in direct contact with the implant. In the forming process, the activatived osteoblast cells migrated toward the interface and colonized the surface at the contact areas. This immature woven bone, rich in osteocyte lacunae, was deposited directly onto the implant surface. Osteoblast activity was found to continue ill 12 weeks of implantation The osteoblasts in lacunar areas developed numerous processes and synthesized bone matrix, after all, surrounded by secreting matrix. At the 12th week, the amount of newly formed bone matrix between bone and implant increased in mineralization. The mineralized mature bone contained well organized collagen fibers with characteristic banding pattern bone tissue formation around the implant.

• 센서학회지
• /
• 제18권4호
• /
• pp.269-273
• /
• 2009

In this paper, a study on a portable hydrogen alarm system based on the palladium coated single mode fiber sensor has been reported. The fabricated hydrogen sensor exhibited 0.14 dB, 0.41 dB and 0.54 dB optical intensity variation when it was exposed by the nitrogen and hydrogen mixed gas containing 0.5 %, 1 % and 4 % of the hydrogen concentration, respectively. The fabricated sensor exhibited 20 second of response time and 120 second of recovery time for 4 % hydrogen containing gas. The fiber optics layout and software algorithm for detection of hydrogen leakage have been presented. The implanted portable hydrogen alarm system successfully generated an alarm signal when a 4 % hydrogen containing gas was leaked out.

• Journal of Oral Medicine and Pain
• /
• 제32권2호
• /
• pp.187-200
• /
• 2007

이 연구는 치과임플란트 시술후에 발생할수 있는 감각이상의 평가를 위하여 뉴로미터를 사용하여 정량적으로 측정하여, 임플란트 시술후의 감각신경 평가에 개관적 지침을 마련하고자 하는데 목적이 있다. 2006년 대전 썬 병원 구강내과에 내원한 환자중에 임플란트 술식을 시행한 환자 44명과 대조군 30명을 대상으로 $Neurometer^{(R)}$ CPT/C (Neurotron, Inc., Baltimore, Maryland, U.S.A.)를 이용하여 임플란트 시술전과 시술후 발사시에 2000 Hz, 250 Hz, 5 Hz,주파수로 검사를 시행하였다. 측정 부위는 임플란트 시술부위에 따라 삼차신경의 상악신경 분지와 하악신경 분지에 적용하였다. Neurometer는 세가지의 주파수 (2000 Hz, 250 Hz, 5 Hz)를 적용할 수 있는데, 각 주파수별로 대상자가 감각을 느낄 수 있는 가장 낮은 전류의 세기를 전류인지역치로 기록하였다. 각 신경섬유별 전류인지역치는 $A{\beta}$섬유의 경우 2000 Hz, $A{\delta}$섬유의 경우 250 Hz의 전류자극 하에서 특징적으로 반응하며, C섬유의 경우 5 Hz의 전류자극 하에서 반응한다. 전류인지역치 검사는 삼차신경 영역에 있어서도 말초신경 손상을 평가하기 위하여 검사를 시행할 수 있으며, 말초신경부위에 특징적인 주파수의 전류를 발생시켜 선택적인 신경 섬유를 자극한다. 서로 다른 굵기의 신경 섬유들은 각기 다른 빈도의 전류자극에 선택적으로 반응하는데, 각기 다른 주파수의 전류자극을 적용하며, 각 전류에 선택적으로 반응하는 $A{\beta},\;A{\delta}$, C신경 섬유의 반응 역치를 개별적으로 평가할 수 있다. 전류인지역치를 통한 평가에서는 전류인지 역치의 증감을 측정하여 감각과민이나 감각감퇴등의 감각이상을 진단할 수 있다. 임플란트 시술전후의 전류인지역치를 평가한 본 연구에서는 다음과 같은 결과를 얻었다. 1. 임플란트 시술 전후의 평가에서는 좌우 상하악 각각의 2000 Hz, 250 Hz, 5 Hz에서의 전류인지역치는 전반적으로 수술 후가 증가되었으며, 하악에서는 2000 Hz와 5 Hz에서 수술후에의 전류인지역치가 통계학적으로 유의하게 증가하였다. 2. 전신질환을 가지고있거나 그로 인하여 투약중인 군에서는 임플란트 수술 전후에 유의한 차이가 없었으며, 대조군에 비해서는 좌측 2000 Hz와 5 Hz에서 임플란트 시술군이 전류인지역치가 유의하게 높았다. 3. 대조군과 임플란트 수술군의 수술전의 전류인지역치 측정치의 비교에서는 우측 2000 Hz, 5 Hz에서 임플란트 시술군이 유의하게 높았으며, 대조군과 임플란트 수술후의 전류 인지 역치 평가에서는 2000 Hz에서 유의한 차이를 보였다. 4. 남자가 여자보다는 전류인지역치가 높았으나, 통계학적인 유의성을 보이지는 않았으며, 임플란트 시술군내에서도 남녀차이는 보이지 않았으며, 대조군에서 좌측 2000 Hz에서 유의하게 낮았다. 임플란트 시술 전후의 전류인지 평가에서 남녀성별에 따른 차이는 남자군에서는 통계학적 차이가 없었고, 여자군에서 우측 5 Hz, 좌측 2000 Hz에서 유의하게 높았다. 5. 감각신경이 있다고 호소하는 군과 아닌 군과의 비교에서는 감각이상을 호소하는 군이 전체적으로 전류인지역치가 증가했으나 통계학적인 유의성은 없었다. VAS상에 증가를 보이는 군의 수술전후의 전류인지측정 평가에서는 우측 5 Hz에서 임플란트 시술후 전류인지역치가 유의하게 증가하였으며, VAS 표시가 수술전후에 모두 0 인 경우에 좌측 2000 Hz에서 수술후의 전류인지역치가 유의하게 증가하였다. 이 연구는 뉴로미터를 이용하여 치아 임플란트 시술후에 발생할 수 있는 감각이상을 평가 할수 있는 객관적이고 정량적인 전류인지역치를 제시하고자 하였다.

• Journal of Periodontal and Implant Science
• /
• 제24권1호
• /
• pp.109-119
• /
• 1994

An essential fact in the regeneration of new periodontal tissue after periodontal therapy is the reattachment of collagen fibers to the tooth. Two phenomena play a fundamental role in preventing new connective tissue attachment to the exposed root surface ; 1) The apical migration of the junctional epithelium 2) The contamination of cementum by toxic substances, especially endotoxins. Authors have used rat submucosal implantation of root sections to study the connective tissue healing to periodontally diseaed root, previously planed and demineralized with citric acid and tetracycline- HCl. The results were obtained as follows. 1. The connective tissue attachment was increased in tetracycline, citric acid, non disease, scaling and root planing order and inflammatory reaction was seen in the rat teeth, no treatment group. 2. Collagen fiber attachment at the dentin surface was more increased than cementum surface 3. In 2 week of citric acid and tetracycline-HCl specimens, osteoid was seen near the fibrotic band. 4. In the MT view, collagen fiber formation was increased with time and the numerous collagen fiber and connective tissue was more densly attached to the tooth surfaces in the tetracycline-HCl group than the citric acid group.

• Journal of Korean Neurosurgical Society
• /
• 제59권6호
• /
• pp.647-649
• /
• 2016

The device for intervertebral assisted motion (DIAM) is a dynamic implant that consists of a silicone bumper enveloped by a polyethylene terephthalate (PET) fiber sack. Silicone and PET were used because of their biological inertness, but repetitive motion of the spine can cause wear on the implant nonetheless. The purpose of this study is to report a case of foreign body reaction (FBR) against a DIAM. A 72-year-old female patient presented with lower back pain and both legs radiating pain. She had undergone DIAM implantation at L4-5 for spinal stenosis 5 years previously. The intervertebral disc space of L4-5, where the DIAM was inserted, had collapsed and degenerative scoliosis had developed due to left-side collapse. MRI showed L3-4 thecal sac compression and left L4-5 foraminal stenosis. The patient underwent removal of the DIAM and instrumented fusion from L3 to L5. During surgery, fluid and granulation tissue were evident around the DIAM. Histopathology showed scattered wear debris from the DIAM causing chronic inflammation due to the resulting FBR. A FBR due to wear debris of a DIAM can induce a hypersensitivity reaction and bone resorption around the implant, causing it to loosen.

• 한국염색가공학회지
• /
• 제30권2호
• /
• pp.117-129
• /
• 2018

Cellulose has been widely applied into various medical fields including scaffolding, tissue engineering and tissue formation. In this study, we manufactured cellulose medical fiber from Styela clava tunics(SCT-CS) and analyzed the tensile strength, elongation at break, fluid uptake and surface morphology. And then, the biocompatibility and toxicity of SCT-CS were measured in Sprague-Dawley(SD) rats after the implantation for 30, 60 and 90 days. The level of tensile strength and fluid uptake were lower in SCT-CS than chromic catgut(CCG), while elongation at break level were maintained the higher in SCT-CS. Also, the roughness with pronounced surface patterns as a result of in vivo degradation was significantly greater in CCG than this of SCT-CS although these levels gradually appeared with time in both groups. After implantation for 90 days, SCT-CS and CCG was successfully implanted around muscle of thigh without any significant immune response. Furthermore, no significant alterations were measured in serum parameters and the specific pathological features induced by most toxic compounds for liver and kidney toxicity. Therefore, these results suggest that SCT-CS showing good biocompatibility and non-toxicity can be successfully prepared from cellulose powder of SCT as well as has the potential for use as a powerful biomaterial for medical sutures.

• Applied Microscopy
• /
• 제29권1호
• /
• pp.1-10
• /
• 1999

본 연구는 정자저장형에 속하는 한국산 관박쥐와 지연착상형에 속하는 한국산 긴가락박쥐 정자들의 형태를 각각 비교 관찰하였다. 정자두부의 형태에 있어서, 관박쥐는 긴 탄환형이었고, 긴가락박쥐는 주걱형이었다. 관박쥐는 두부의 2/3부분이 핵으로 이루어져 있었고, 긴가락박쥐는 1/2부분이 핵으로 이루어져 있었다. Segmented column들은 관박쥐의 경우 $12\sim14$층으로 이루어져 있었고, 긴가락박쥐의 경우 $10\sim12$층으로 이루어져 있었다. 특히 satellite fiber의 경우 관박쥐는 중편부의 외측섬유들 사이에 존재하고 있지만, 긴가락박쥐는 존재하지 않았다. 이상의 관찰 결과에서 볼 때 이들 박쥐정자의 외형 및 내부 구조적 특징들이 생식패턴과 관련이 있을 것으로 여겨진다.

• Macromolecular Research
• /
• 제16권4호
• /
• pp.345-352
• /
• 2008

Poly(lactic-co-glycolic acid) (PLGA) tubes (5 mm in diameter) were fabricated using an electro spinning method and used as a scaffold for artificial blood vessels through the hybridization of smooth muscle cells (SMCs) and endothelial cells (ECs) differentiated from canine bone marrow under previously reported conditions. The potential clinical applications of these artificial blood vessels were investigated using a canine model. From the results, the tubular-type PLGA scaffolds for artificial blood vessels showed good mechanical strength, and the dual-layered blood vessels showed acceptable hybridization behavior with ECs and SMCs. The artificial blood vessels were implanted and substituted for an artery in an adult dog over a 3-week period. The hybridized blood vessels showed neointimal formation with good patency. However, the control vessel (unhybridized vessel) was occluded during the early stages of implantation. These results suggest a shortcut for the development of small diameter, tubular-type, nanofiber blood vessels using a biodegradable material (PLGA).