• Journal of Microbiology and Biotechnology
• /
• 제20권5호
• /
• pp.862-870
• /
• 2010

Cyperus rotundus L. is a perennial herb that was found to be dominating an area in northeast Brazil previously contaminated with petroleum. In order to increase our knowledge of microorganism-plant interactions in phytoremediation, the bacterial community present in the rhizosphere and roots of C. rotundus was evaluated by culture-dependent and molecular approaches. PCR-DGGE analysis based on the 16S rRNA gene showed that the bacterial community in bulk soil, rhizosphere, and root samples had a high degree of similarity. A complex population of alkane-utilizing bacteria and a variable nitrogen-fixing population were observed via PCR-DGGE analysis of alkB and nifH genes, respectively. In addition, two clone libraries were generated from alkB fragments obtained by PCR of bulk and rhizosphere soil DNA samples. Statistical analyses of these libraries showed that the compositions of their respective populations were different in terms of alkB gene sequences. Using culturedependent techniques, 209 bacterial strains were isolated from the rhizosphere and rhizoplane/roots of C. rotundus. Dot-blot analysis showed that 17 strains contained both alkB and nifH gene sequences. Partial 16S rRNA gene sequencing revealed that these strains are affiliated with the genera Bosea, Cupriavidus, Enterobacter, Gordonia, Mycoplana, Pandoraea, Pseudomonas, Rhizobium, and Rhodococcus. These isolates can be considered to have great potential for the phytoremediation of soil with C. rotundus in this tropical soil area.

• Journal of Forest and Environmental Science
• /
• 제10권1호
• /
• pp.8-24
• /
• 1994

수목(樹木)의 뿌리는 수목(樹木)의 생장(生長)과 토양(土壤)의 구조개선(構造改善)에 밀접한 관계가 있음에도 불구하고 지하부(地下部)에 위치하고 있으므로 연구가 미진한 상태이다. 따라서 각 수종(樹種)의 근계(根系)의 발달상태를 파악하는 것은 그 수종(樹種)의 특성 파악과 뿌리가 지표고정(地表固定)에 미치는 영향을 파악하는데 기초자료로 활용할 수 있다. 본 연구에서는 강원도(江原道) 소나무림(林)의 특성을 파악하기 위한 기초연구의 일부로서 일차적으로 강원대학교(江原大學校) 구내(構內) 소나무림(林)의 근계(根系) 형태(形態) 및 분포(分布)에 대하여 규명하였다. 5개의 공시목(供試木)에 대해 조사한 결과 뿌리의 형태(形態)는 수평근(水平根)이 잘 발달되어 있었다. 뿌리의 분포(分布)에 있어서 크기별로는 세근(細根)은 대부분이 점재(点在)(+)하고 있었음, 태근(太根)은 0.2cm가 대부분이었다. 깊이별로는 태근(太根), 세근(細根) 모두가 10~30cm에서 60~70% 이상 집중되었으며, 태근(太根)은 주로 0.9cm 이하였고, 세근(細根)은 대부분이 점재(点在)(+)하고 있었다.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
• /
• pp.801-804
• /
• 2008

해안 구조물의 내구성 개선을 위해서는 염해저항성이 요구되므로 콘크리트의 수밀성 확보, 균열저항성 및 염소이온을 고정화하는 특성이 요구된다. 따라서 본 연구에서는 기존의 슬래그를 포함한 해안 콘크리트 배합에 유무기복합형 내구성 개선제(HD)를 적용하여 콘크리트의 시공성 및 강도발현에 미치는 영향과 함께 수축저항성이 및 내염해성에 미치는 효과를 파악하였다. HD의 적용에 따라 콘크리트의 수축저항성 및 내염해성이 개선되었으며, 특히 0.6% 적용 시 기존 슬래그를 포함한 배합보다 수축저항성 및 내염해성의 개선효과가 더욱 두드러진 것으로 확인되었다.

• Steel and Composite Structures
• /
• 제22권3호
• /
• pp.537-565
• /
• 2016

Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.

• 대한족부족관절학회지
• /
• 제18권4호
• /
• pp.178-182
• /
• 2014

Purpose: The purpose of this study was to evaluate the frequency of troughing and stress fracture, which are the major complications of scarf osteotomy, and to suggest methods to prevent these complications. Materials and Methods: We reviewed 243 cases of 137 patients treated with the scarf osteotomy for hallux valgus from January 2005 to December 2012. The mean follow-up period was 2.8 years. During the scarf osteotomy, a long oblique longitudinal osteotomy was performed in order to decrease the possibility of troughing and stress fracture. Radiographs of lateral view of the foot were obtained and the thicknesses of the first metatarsal base at the sagittal plane were measured and compared. Results: There was no troughing during fragment translation and screw fixation intraoperatively. Radiographs of lateral view of the foot taken preoperatively and at the last follow-up showed that the mean thickness of the first metatarsal was 22.4 mm preoperatively and 21.6 mm at the last follow-up, with a mean difference of 0.8 mm. And no stress fracture was observed. Conclusion: To prevent troughing and stress fracture, a long oblique longitudinal cut, parallel to the first metatarsal plantar surface, was performed, making both ends of the proximal segment truncated cone-shape, and securing the strong bony strut of the proximal segment. No troughing or stress fracture was experienced with scarf osteotomy.

• Archives of Plastic Surgery
• /
• 제37권6호
• /
• pp.788-794
• /
• 2010

Purpose: The fingertip is the most commonly injured part of the hand and its injury frequently results in avulsion or crushing of a segment of the nail bed and fracture of the distal phalangeal bone. Restoration of a flat and smooth nail bed is essential for regrowth of a normal nail, which is important not only for cosmetic reasons but also for tactile capability of the fingertip. It is also anatomical reduction of the distal phalanx to promote patient's cosmetics and prevent nail bed deformity. Absence or no replacement of the nail plate results in obliterated proximal skin fold. When the avulsed nail plate cannot be returned to its anatomic position or when it is absent, we use a synthetic material for splinting the nail bed and alternative reductional method for distal phalangeal bone fracture, especially, instead of hardwares. Methods: From January of 2006 to June of 2009, a total of ten patients and fourteen fingers with crushing or avulsion injuries of the fingertip underwent using the artificial nails for finger splint. We shaped artificial nails into the appropriate sizes for use as fingernail plates. We placed them under the proximal skin fold and sutured to the fold proximally and to the lateral and medial edges of the nail bed or to the distal fingertip. Our splints were as hard as K-wire and other fixation methods and more similar to anatomic nail plates. Artificial nails were kept in place for at least 3 weeks. Results: No artificial nail related complication was noted in any of the ten cases. No other nail fold or nail bed complications were observed, except for minor distal nail deformity because of trauma. Conclusion: In conclusion, in order to secure the nail bed after injury and reduce the distal phalangeal bone fracture, preparing a nail bed splint from a artificial commercial nail is a cheap and effective method, especially, for crushed or avulsion injuries of the fingertip.

• Journal of Chest Surgery
• /
• 제21권4호
• /
• pp.619-629
• /
• 1988

The increasing number of replacement of the substitute cardiac valves were seen in these 2 years. Out of a total 1,408 patients with cardiac valve replacement, 54 required replacement of the substitute valves. Fifty-nine substitute valves replaced were 43 in mitral, 14 in aortic and 2 in tricuspid positions; and they were 36 Ionescu-Shiley, 15 Hancock and 3 Angell-Shiley bioprosthetic valves and 3 St. Jude Medical and 2 Bjork-Shiley prosthetic valves. Primary tissue failure was the most frequent reason of replacement[38 patients] followed by paravalvular leak[9 patients], prosthetic valve endocarditis[6 patients] and valve thrombosis[1 patient] in order. The most pronounced pathology of the failed xenograft valves seen in the primary tissue failure group was calcification and fixation of the cusps with or without tear and defect of the cuspal tissue. The operative mortality rate was 7.4%. Fifty early survivors were followed up for a total of 82.6 patient-years and there was no late death. Actuarial survival rate was 92.3*3.8% at 6 years after surgery. Although the definite tendency toward early and accelerated degeneration of the xenograft valves has been seen in patients younger than 20 to 25 years of age, no strict age limit from where the tissue failure slows down could be determined. The requirement of the ideal substitute valves would be the durability of the recently developed mechanical prostheses armed with the low thrombogenicity of the bioprostheses. At the present time, the need of compromise in selection between less thrombogenic bioprosthetic and more durable mechanical valves should be stressed. The difficulty in choice is yet important in patients of middle age and children where the use of homograft valves may be one of the solution despite of certain limitations from sociomedical reasons.

• 자원리싸이클링
• /
• 제6권3호
• /
• pp.28-35
• /
• 1997

조개껍질(굴, 고막)을 수처리재로 활용하기 위한 기초 실험으로 중금속(Cd, Cu, Fe, Mn, Pb, Zn)과 유기성분(TCE(Trichlo-roethylene)와 PCE(Tetrachroethylene))의 흡착능을 조사했다. 수산화칼슘으로 이루어진 굴과 고막껍질의 소성 분말 주입에 따른 중금속 제거효율은 Mn, Zn, Fe, Cd, Cu, Pb의 순이었다. 우수한 중금속 흡착능은 조개껍질의 $Ca(OH)_2$ 성분에 의한 높은 pH유지에 따른 중금속 탄산염과 수산화물의 형성에 의한 침전작용, 조개껍질의 칼슘 매트릭스 구조에 의한 중금속의 고정화와 잔존하는 불용성 유기물의 결합 등의 작용이라고 본다. 이와 같은 굴껍질은 침출수의 중화작용과 동시에 우수한 중금속 흡착능을 가지고 있어, 이것을 수처리로 활용될 경우, 저렴한 재료의 확보와 더욱이 부가가치가 높은 폐부산자원을 활용한 정화용 세라믹스 담체의 개발로 폐부산자원 폐기처리 문제 이외의 환경정화용 세라믹스 및 담체 등의 환경분야 사업으로 확장 발전시킬 수 있다고 본다.

• 대한금속재료학회지
• /
• 제49권12호
• /
• pp.983-988
• /
• 2011

Failure analyses of the screws in spinal fixation devices were carried out. The fractured screws were retrieved from a patient who had spinal surgery in the thoracic vertebrae from number 10 to 15. The failure occurred one month after the removal of the braces. Microstructures and fracture surfaces were examined by optical and scanning electron microscopy. The microstructures of the screws corresponded to annealed Ti-6Al-4V bar. However, in the vicinity of the screw surface, there was an insufficient number of fine precipitates. Fracture surfaces showed typical fatigue failure modes. Regarding the fact that no machining defects were detected, fatigue crack initiation might have been caused by the lack of precipitates near the screw surfaces. Only the fourth of five fixed screws was severely stress-concentrated by the action of the spinal bones, while the stress of the 4th screw was decreased to half of its acceptable level when the screw was supplemented by one more, which might have been fixed in the 6th vertebra under the 5th position by the switching of its position. The stress simulation was conducted by ANSYS with 3D CAD of PRO/E in order to understand the stress concentration behavior and to provide an effective spinal surgery guide.

• 대한방사선기술학회지:방사선기술과학
• /
• 제42권1호
• /
• pp.61-66
• /
• 2019

The purpose of this study was to improve the unstable treatment posture by placing the Carbon fabric blanket on the couch which was used for the patient fixation for the unstable posture from the severe pain caused by the neuromuscular pressure of the spinal metastatic cancer patient and to analyze the dose difference caused by the energy loss of high energy radiation. Using a linear accelerator, a FC-65G was installed at a depth of 5 cm at a solid phantom at 6 MV and 10 MV energies. The SAD was 100 cm, Gantry angle was $0^{\circ}$, a Cotton and Carbon blanket with a thickness of 1 cm on the couch, The blankets were placed on the couch and the dose was measured according to field size. For the dose measurement, and the dose was measured at 100 MU each time, and the mean value was calculated by repeating the measurement three times in order to reduce the error. The results showed that the difference rate in dose between Carbon blanket and Cotton blanket was respectively -0.54% and -0.75% based on the absence of the blanket(Non). Therefore, it is considered that the use of Carbon fabric blanket, which reduces the patient's pain and does not affect the depth dose, may be useful during radiation therapy of the spine metastasis cancer.