• 제목/요약/키워드: persistence length

검색결과 28건 처리시간 0.023초

Benefits and risks of therapeutic alternatives for macrolide resistant Mycoplasma pneumoniae pneumonia in children

  • Yang, Hyeon-Jong
    • Clinical and Experimental Pediatrics
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    • 제62권6호
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    • pp.199-205
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    • 2019
  • Although Mycoplasma pneumoniae pneumonia (MPP) has been generally susceptible to macrolides, the emergence of macrolide-resistant MPP (MRMP) has made its treatment challenging. MRMP rapidly spread after the 2000s, especially in East Asia. MRMP is more common in children and adolescents than in adults, which is likely related to the frequent use of macrolides for treating M. pneumoniae infections in children. MRMP is unlikely to be related to clinical, laboratory, or radiological severity, although it likely prolongs the persistence of symptoms and the length of hospital stay. Thereby, it causes an increased burden of the disease and poor quality of life for the patient as well as a societal socioeconomic burden. To date, the only alternative treatments for MRMP are secondary antimicrobials such as tetracyclines (TCs) or fluoroquinolones (FQs) or systemic corticosteroids; however, the former are contraindicated in children because of concerns about potential adverse events (i.e., tooth discoloration or tendinopathy). A few guidelines recommended TCs or FQs as the second-line drug of choice for treating MRMP. However, there have been no evidence-based guidelines. Furthermore, safety issues have not yet been resolved. Therefore, this article aimed to review the benefits and risks of therapeutic alternatives for treating MRMP in children and review the recommendations of international or regional guidelines and specific considerations for their practical application.

A review of experimental and numerical studies on crack growth behaviour in rocks with pre-existing flaws

  • G. Sivakumar;V.B. Maji
    • Geomechanics and Engineering
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    • 제35권4호
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    • pp.333-366
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    • 2023
  • Rock as a mass generally exhibits discontinuities, commonly witnessed in rock slopes and underground structures like tunnels, rock pillars etc. When these discontinuities experiences loading, a new crack emerges from them which later propagates to a macro scale level of failure. The failure pattern is often influenced by the nature of discontinuity, geometry and loading conditions. The study of crack growth in rocks, namely its initiation and propagation, plays an important role in defining the true strength of rock and corresponding failure patterns. Many researchers have considered the length of the discontinuity to be fully persistent on rock or rock-like specimens by both experimental and numerical methods. However, only during recent decades, there has been a substantial growth in research interest with non-persistent discontinuities where the crack growth and its propagation phenomenon were found to be much more complex than persistent ones. The non-persistence fractures surface is generally considered to be open and closed. Compared to open flaws, there is a difference in crack growth behaviour in closed or narrow flaws due to the effect of surface closure between them. The present paper reviews the literature that has contributed towards studying the crack growth behaviour and its failure characteristics on both open and narrow flaws subjected to uniaxial and biaxial compression loading conditions.

Exploring shrinkage crack propagation in concrete: A comprehensive analysis through theoretical, experimental, and numerical approaches

  • Vahab Sarfarazi;Soheil Abharian;Nima Babanouri
    • Computers and Concrete
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    • 제34권1호
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    • pp.15-31
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    • 2024
  • This study explores the failure mechanisms of 'I' shaped non-persistent cracks under uniaxial loads through a combination of experimental tests and numerical simulations. Concrete specimens measuring 200 mm×200 mm×50 mm were manufactured, featuring 'I' shaped non-persistent joints. The number of these joints varied from one to three, with angles set at 0, 30, 60, and 90 degrees. Twelve configurations, differing in the placement of pre-existing joints, were considered, where larger joints measured 80 mm in length and smaller cracks persisted for 20 mm with a 1 mm crack opening. Numerical models were developed for the 12 specimens, and loading in Y-axis direction was 0.05 mm/min, considering a concrete tensile strength of 5 MPa. Results reveal that crack starting was primarily influenced by the slope of joint that lacks persistence in relation to the loading direction and the number of joints. The compressive strength of the samples exhibited variations based on joint layout and failure mode. The study reveals a correlation between the failure behavior of joints and the number of induced tensile fracture, which increased with higher joint angles. Specimen strength increased with decreasing joint angles and numbers. The strength and failure processes exhibited similarities in both laboratory testing and numerical modeling methods.

Comparison of Full Genome Sequences Between Two Hepatitis B Virus Strains With or Without preC Mutation (A1896) from a Single Korean Hepatocellular Carcinoma Patient

  • Kim, Hong;Jee, Young-Mee;Mun, Ho-Suk;Song, Byung-Cheol;Park, Joo-Hee;Hyun, Jin-Won;Hwang, Eung-Soo;Cha, Chang-Yong;Kook, Yoon-Hoh;Kim, Bum-Joon
    • Journal of Microbiology and Biotechnology
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    • 제17권4호
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    • pp.701-704
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    • 2007
  • This report describes the full-length sequences of 2HBV clones from a hepatocellular carcinoma (HCC) patient, one with preC mutation (1896A) and the other without preC mutation. The high level of discrepancy in mutation frequency between these 2 strains was observed in the Core (C) region among 4 ORFs. These data support previous results that Korean HBV strains, belonging to genotype C2, are prone to mutations. It is possible that the mutations (BCP and preC mutations) associated with the HBeAg defective production might contribute to the diversity of mutations related to HBV persistence, playing an important role in hepatocarcinogenesis in this patient.

A unique genetic lineage at the southern coast of China in the agar-producing Gracilaria vermiculophylla (Gracilariales, Florideophyceae)

  • Hu, Zi-Min;Liu, Ruo-Yu;Zhang, Jie;Duan, De-Lin;Wang, Gao-Ge;Li, Wen-Hong
    • ALGAE
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    • 제33권3호
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    • pp.269-278
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    • 2018
  • Ocean warming can have significant negative impacts on population genetic diversity, local endemism and geographical distribution of a wide range of marine organisms. Thus, the identification of conservation units with high risk of extinction becomes an imperative task to assess, monitor, and manage marine biodiversity for policy-makers. Here, we surveyed population structure and genetic variation of the red seaweed Gracilaria vermiculophylla along the coast of China using genome-based amplified fragment length polymorphism (AFLP) scanning. Regardless of analysis methods used, AFLP consistently revealed a south to north genetic isolation. Populations at the southern coast of China showed unique genetic variation and much greater allelic richness, heterozygosity, and average genetic diversity than the northern. In particular, we identified a geographical barrier that may hinder genetic exchange between the two lineages. Consequently, the characterized genetic lineage at the southern coast of China likely resulted from the interplay of post-glacial persistence of ancestral diversity, geographical isolation and local adaptation. In particular, the southern populations are indispensable components to explore evolutionary genetics and historical biogeography of G. vermiculophylla in the northwestern Pacific, and the unique diversity also has important conservation value in terms of projected climate warming.

샤넬 재킷 디자인의 구성학적 요소 분석 (Analysis of the Constructional Components of Chanel Jacket Design)

  • 최세린;도월희;이미숙
    • 한국의류산업학회지
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    • 제20권3호
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    • pp.266-278
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    • 2018
  • This study investigated the transformation of the Chanel jacket by looking at clothing design and constructional components. This study explored Chanel jacket's designs from 2001 S/S to 2016-17 F/W, and collected designs from Samsung Design Net and Vogue. The study used 690 designs with the following results. First, in the silhouette of the Chanel jacket, straight silhouette and hourglass silhouette had the most; in addition, in the length, hip line and under hip line were in order. Second, in case of collar and neckline, the form of a non-collar was the most and revealed the persistence of round neckline which is the basic style of a Chanel jacket. Third, in the shape of sleeves, the loose-fit straight sleeves, wide sleeves, and cocoon sleeves appeared most often. In method of closure, button, zipper were in order, and snaps or without closure appeared. Fourth, in the form of braids, various forms such as twisted yarns, leashes, or lace were used, and patch pockets were mainly used in pockets. Chanel maintains its original design by using various methods. Chanel tried to improve activity and functionality through silhouettes, lengths, necklines, and sleeves. The unchanging expression of the world of Chanel will continue to display and inherit future value. This study can provide Chanel's unique characteristics and new ideas that can transform their origins for jacket design.

DNAPL Pool의 용해실험에 의한 분산계수 산정 (Calculation of the Dispersion Coefficient by the Dissolution Experiment of DNAPL Pool)

  • 정경영;배열호;최상일
    • 한국토양환경학회지
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    • 제1권1호
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    • pp.19-27
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    • 1996
  • 물에 쉽게 용해되지 않고 분리된 유체면을 갖는 액체를 NAPO(nonaqueous phase liquids)이라 한다. 유기용제와 석유탄화수소와 같은 NAPL에 의한 지하수 오염은 지하에서의 장기간의 지속성 및 다량의 지하수를 오염시키는 능력 때문에 주요 관심 대상물질이다 누출된 DNAPU(denser- than-water NAPL)은 궁극적으로 포화 대수층을 통과하여 바닥에 DNAPL pool을 이루게 된다. 이러한 pool로부터의 용해는 분자확산계수, 연직분산도, 지하수유속, 용해도 및 pool의 길이에 지배된다. 본 연구에서는 이러한 DNAPL pool의 용해를 모사하기 위해 DNAPL용해실험을 하여 연직 횡분산계수를 산정하였다. 본 연구에서 사용된 실험조건하에서 수행한 실험결과 산정된 연직 횡분산계수는 침투유속이 59.2cm/day, 94.3cm/day 및 158.0cm/day인 경우 각각 1.86$cm^2$/day, 2.90$cm^2$/day 및 4.51$cm^2$/day 이었고, 연직 횡분산도는 0.03024cm 이었다.

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폐경기 골다공증 환자에서 데노수맙 사용에 대한 비용-효과 분석 (Cost-Effectiveness of Denosumab for Post-Menopausal Osteoporosis in South Korea)

  • 배그린;권혜영
    • 한국임상약학회지
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    • 제28권2호
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    • pp.131-137
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    • 2018
  • Background: In South Korea, 22.3% of women ${\geq}50years$ of age and 37% of women ${\geq}70years$ of age visit the doctor to obtain treatment for osteoporosis. According to the analysis of the National Health Insurance Services claim data between 2008 and 2012, the number and incidence of hip and vertebral fractures increased during the same period. Denosumab, a newly marketed medicine in Korea, is the first RANK inhibitor. Methods: A cost-utility analysis was conducted from a societal perspective to prove the superiority of denosumab to alendronate. A Markov cohort model was used to investigate the cost-effectiveness of denosumab. A 6-month cycle length was used in the model, and all patients were individually followed up through the model, from their age at treatment initiation to their time of death or until 100 years of age. The model consisted of eight health states: well; hip fracture; vertebral fracture; wrist fracture; other osteoporotic fracture; post-hip fracture; post-vertebral fracture; and dead. All patients began in the well-health state. In this model, 5% discounted rate, two-year maximum offset time, and persistence were adopted. Results: The total lifetime costs for alendronate and denosumab were USD 5,587 and USD 6,534, respectively. The incremental cost-effectiveness ratio (ICER) for denosumab versus alendronate was USD 20,600/QALY. Given the ICER threshold in Korea, the results indicated that denosumab was remarkably superior to alendronate. Conclusion: Denosumab is a cost-effective alternative to the oral anti-osteoporotic treatment, alendronate, in South Korea.

Alginate에 고정화된 Arthrobacter woluwensis ED 처리 시 토마토의 생장촉진과 균주의 토양 내 잔류 (Growth Promotion of Tomato by Application of Immobilized Arthrobacter woluwensis ED in Alginate Beads)

  • 권승탁;송홍규
    • 미생물학회지
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    • 제50권1호
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    • pp.40-45
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    • 2014
  • 전 세계적으로 친환경 농업을 위해 식물생장촉진 근권세균을 이용한 미생물 비료에 대한 관심이 증가하고 있는데 투여하는 세균을 식물 근권에 보다 장기간 잔류시키기 위해 식물생장 촉진능이 있는 균주를 alginate bead에 고정화하여 식물생장을 조사하였다. 발아된 토마토 유묘에 Arthrobacter woluwensis ED를 $1{\times}10^6$ cells/g 로 처리하고 30일 재배 후 자라난 토마토의 shoot와 뿌리 길이 및 습윤과 건조중량을 측정한 결과 비접종 대조군과 비교하여 균주 현탁액 접종군은 각각 36.2, 59.0, 51.1과 37.5%씩 유의성 있게 증가하였으며 고정화 균주 접종군은 각각 42.0, 67.4, 62.5와 60.4%씩 유의성 있게 증가하였다. 고정화 균주 접종군은 균주 현탁액 접종군에 비하여 각각 6, 8, 11과 23% 증가하였다. 접종 균주가 식물 근권에서 유지되는 양상을 관찰하기 위해 denaturing gradient gel electrophoresis를 이용하여 토양세균 군집을 분석하였는데 균주 현탁액 접종군에서 ED 균주의 DNA band intensity는 접종일로부터 1주일까지 가장 높게 나타났으나 그 이후로 감소하여 접종 2주 후 비접종 대조군과 비슷한 band intensity를 나타내었다. 반면, 고정화 균주 접종군의 ED 균주 band intensity는 접종일로부터 초기에는 비접종 대조군과 비슷하였으나 이후 급격하게 증가하여 계속 높게 유지되어 3주까지 band intensity가 현탁액 접종군 보다 높았다. 따라서 alginate에 A. woluwensis ED를 고정하여 적용하는 방법이 현탁액 적용보다 식물 근권에 균주의 공급을 효과적으로 유지하면서 식물생장을 더욱 촉진하는 것으로 나타났다.

한국 서울 식생의 번성자로서 팥배나무의 형질 변화 양상 (Changes in Leaf and Reproductive Traits of Mountain Ash (Sorbus alnifolia) as Urban Flourisher in the Seoul Metropolitan, South Korea)

  • 정성희;조용찬;이창석
    • 한국환경생태학회지
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    • 제35권6호
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    • pp.644-658
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    • 2021
  • 도시 생태계에서 우점 수종의 형질 특성은 분획화 및 고립된 식생, 그리고 생물상호작용 감소 등 환경 변화에 대한 종의 형질 적응과 생태계 기능에 대한 통찰력을 제공한다. 우리는 한국의 서울 중심에서 남쪽 방향의 4개 산지에서 환경 요인 (지리, 기상 및 토양 속성)을 포함하여 모두 40개체 팥배나무 (Sorbus alnifolia)에서 측정한 4개 유형의 잎 형질 (Leaf area, Specific leaf area, Leaf dry mass content, Leaf shape index)과 7개 유형의 번식 형질 (Fruit width, Fruit length, Fruit shape, Fruit dry weight, Fruit dry matter content, Seed weight 및 Seed ratio)의 평균과 분산 양상, 그리고 형질 조합에 대한 다변량 분석을 실시하였다. 측정된 환경 요인은 조사 장소의 개별성을 나타내었지만, 도심 식생이 더 건조하고 생장도일이 길었다. 도심에서 팥배나무의 잎은 작고 무거워지며, 열매는 길쭉하고 가벼운 종자를 생산하여, 오랜 도시화 영향에 따른 형질 반응들이 관찰되었다. 우리의 연구는 식생 파편화 및 고립화에 따른 생물 상호작용 감소를 나타내는 도심 환경에서 팥배나무 집단의 성장 및 번식 기제의 변화를 확인하였다. 우리는 축소된 생물 상호작용 규모, 그리고 대기 오염 같은 부정적 환경 요인이 많은 도시에서 핵심 수종의 기능과 지속성에 관해 제한적이지만 뚜렷한 생태 정보를 제공한다.