• 정보보호학회논문지
• /
• 제32권5호
• /
• pp.845-853
• /
• 2022

스마트폰의 메모리 용량이 증가하면서 스마트폰에 저장된 개인 정보의 종류와 양도 증가하고 있다. 하지만 최근 악의적인 공격자의 악성 앱이나 수리기사 등의 타인으로 인해 스마트폰의 사진, 동영상 등의 다양한 개인 정보가 유출될 가능성이 증가하고 있기 때문에, 사용자의 이러한 개인 정보를 보호할 수 있는 다양한 정보 은닉 앱이 출시되고 있다. 본 논문은 이러한 정보 은닉 앱의 암호 알고리즘 및 데이터 보호 기능을 분석하여 안전성 및 취약점을 분석 및 연구했다. 이를 위해 우리는 Google Play에 등록된 정보 은닉 앱 중에서 전 세계적으로 가장 많이 다운로드된 AppLock 3.3.2 버전(December 30, 2020)과, 5.3.7 버전(June 13, 2022)을 분석했다. 접근 제어 기능의 경우, 사용자가 입력한 패턴을 암호화하기 위한 값들이 소스 코드에 평문으로 하드코딩 되어있으며 암호 알고리즘이 적용된 패턴 값은 xml 파일에 저장한다는 취약점이 존재했다. 또한 금고 기능의 경우 금고에 저장하기 위한 파일과 로그 파일을 암호화하지 않는 취약점이 존재했다.

• Journal of Animal Science and Technology
• /
• 제65권1호
• /
• pp.16-31
• /
• 2023

Cultured meat is a potential sustainable food generated by the in vitro myogenesis of muscle satellite (stem) cells (MSCs). The self-renewal and differentiation properties of MSCs are of primary interest for cultured meat production. MSC proliferation and differentiation are influenced by a variety of growth factors such as insulin-like growth factors (IGF-1 and IGF-2), transforming growth factor beta (TGF-β), fibroblast growth factors (FGF-2 and FGF-21), platelet-derived growth factor (PDGF) and hepatocyte growth factor (HGF) and by hormones like insulin, testosterone, glucocorticoids, and thyroid hormones. In this review, we investigated the roles of growth factors and hormones during cultured meat production because these factors provide signals for MSC growth and structural stability. The aim of this article is to provide the important idea about different growth factors such as FGF (enhance the cell proliferation and differentiation), IGF-1 (increase the number of myoblasts), PDGF (myoblast proliferation), TGF-β1 (muscle repair) and hormones such as insulin (cell survival and growth), testosterone (muscle fiber size), dexamethasone (myoblast proliferation and differentiation), and thyroid hormones (amount and diameter of muscle fibers and determine the usual pattern of fiber distributions) as media components during myogenesis for cultured meat production.

• Restorative Dentistry and Endodontics
• /
• 제46권1호
• /
• pp.1.1-1.13
• /
• 2021

Objectives: The aim of this study was to evaluate the dystrophic mineralization deposits from 3 calcium silicate-based cements (Micro-Mega mineral trioxide aggregate [MM-MTA], Biodentine [BD], and EndoSequence Root Repair Material [ESRRM] putty) over time after subcutaneous implantation into rats. Materials and Methods: Forty-five silicon tubes containing the tested materials and 15 empty tubes (serving as a control group) were subcutaneously implanted into the backs of 15 Wistar rats. At 1, 4, and 8 weeks after implantation, the animals were euthanized (n = 5 animals/group), and the silicon tubes were removed with the surrounding tissues. Histopathological tissue sections were stained with von Kossa stain to assess mineralization. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDX) were also used to assess the chemical components of the surface precipitates deposited on the implant and the pattern of calcium and phosphorus distribution at the material-tissue interface. The calcium-to-phosphorus ratios were compared using the non-parametric Kruskal-Wallis test at a significance level of 5%. Results: The von Kossa staining showed that both BD and ESRRM putty induced mineralization starting at week 1; this mineralization increased further until the end of the study. In contrast, MM-MTA induced dystrophic calcification later, from 4 weeks onward. SEM/EDX showed no statistically significant differences in the calcium- and phosphorus-rich areas among the 3 materials at any time point (p > 0.05). Conclusions: After subcutaneous implantation, biomineralization of the 3-calcium silicate-based cements started early and increased over time, and all 3 tested cements generated calcium- and phosphorus-containing surface precipitates.

• Archives of Reconstructive Microsurgery
• /
• 제6권1호
• /
• pp.29-38
• /
• 1997

A peripheral nerve when approximation of the ends imparts tension at the anastomosis and with a relatively long segment defect after excision of neuroma and neurofibroma cannnot be repaired by early primary suture. The one of the optimistic reconstruction method of severed peripheral nerves is to restore tension-free continuity at the repair site putting an autogenous nerve graft into the neural gap despite of ancipating motor or sensory deficit of the donor nerve area. To overcome the deficit of the autogenous nerve graft, several other conduits supplying a metabolically active environment which is able to support axon regeneration and progression, providing protection against scar invasion, and guiding the regrowing axons to the distal stump of the nerve have been studied. An author have used ipsilateral femoral vein, ipsilateral femoral vein filled with fresh thigh muscle, and autogenous sciatic nerve for the sciatic nerve defect of around 10 mm in length to observe the regeneration pattern in rat by light and electron microscopy. The results were as follows. 1. Light microscopically regeneration pattern of nerve fibers in the autogenous graft group was more abundant than vein graft and vein filled with muscle group. 2. On ultrastructural findings, the proxial end of the graft in various groups showed similar regenerating features of the axons, myelin sheaths, and Schwann cells. The fascicular arrangement of the myelinated and unmyelinated fibers was same regardless of the type of conduits. There were more or less increasing tendency in the number and the diameter of myelinated fibers correlated with the regeneration time. 3. In the middle of the graft, myelinated nerve fibers of vein filled with muscle group were more in number and myelin sheath was thinner than in the venous graft, but the number of regenerating axons in autogenous nerve graft was superior to that in both groups of the graft. The amount of collagen fibrils and amorphous materials in the endoneurial space was increased to elapsed time. 4. There was no difference in regenerating patterns of the nerve fibers of distal end of the graft. The size and shape of the myelinated nerve fbers were more different than that of proximal and middle portion of the graft. From the above results, the degree of myelination and regenerating activity in autogenous nerve is more effective and active in other types of the graft and there were no morphological differences in either ends of the graft regardless of regeneration time.

• 공업화학
• /
• 제16권6호
• /
• pp.794-799
• /
• 2005

석유화학산업의 양적인 성장과 더불어 공정 간 연결역할을 하는 배관설비도 또한 증가하여 유지 보수를 위해 매년 많은 예산이 소요된다. 현재 국내에는 배관설비에 대한 가동 중 이상 유무를 진단할 수 있는 기술이 거의 없는데 반해, 선진국을 중심으로 하여 감마선을 이용한 배관진단 기술이 1960대 이후부터 연구되었다. 본 연구에서는 이상 현상을 보이고 있는 가동 중 증류탑 배관에 대한 원인분석 및 그 정도를 파악하기 위하여 밀봉감마선원($^{137}Cs$)과 계측기를 이용하여 현장 실험을 수행하였다. 유체이송 배관을 중심으로 한쪽에는 감마선원과 맞은편에는 계측기를 설치하고 일정간격으로 감마선 투과계측을 하였다. 계측결과로부터 배관 내부에 존재하는 유체와 다른 밀도분포 구간을 발견하였고, 추후 이것이 가스층이었음이 확인됨으로써 현장 관계자에게 유용한 정보를 제공하였다. 감마선을 이용한 배관진단 기술이 내부 유체의 분포상태에 대한 정보를 제공하는데 효율적인 진단기술임을 현장실험을 통해 확인하였다.

• 대한관절경학회지
• /
• 제7권2호
• /
• pp.153-159
• /
• 2003

목적 : 내측 및 외측 반월상연골의 전위된 양동이 손잡이형 파열의 양상과 동반손상에 따른 치료원칙과 결과를 비교하고자 하였다. 대상 및 방법 : 1998년 9월부터 2002년 12월까지 본원에서 내측 반월상 연골의 전위된 양동이 손잡이형 파열(이하 I군)로 진단받은 52명 52예와 외측 반월상 연골의 전위된 양동이 손잡이형 파열(이하 II군)로 진단받은 31명 32예를 대상으로 하였으며, 평균연령은 I군 25세($16\~66$세), II군 29세($18\~63$세)였고, 평균 추시기간은 I군 18개월 ($12\~50$개월), II군 13개월($6\~46$개월)이었다. 술중 관절경 검사를 통하여 연골 파열의 부위, 동반손상 여부를 확인하였으며, 외측의 경우 추가적으로 원판형 연골인 경우를 조사하였다 술 후 최종 추시 시 이학적 검사와 임상양상에 따라 치료 판정을 하였으며, 두 군 전체에서 전방십자인대 파열이 동반되었던 경우 추시 관절경을 19례$(23\%)$에서 시행하였다. 결과 : 전방십자인대 파열이 동반된 경우는 I군 38예$(73\%)$, II군 5예$(16\%)$였으며, 원판형 연골이었던 경우는 II군에서 19예$(59\%)$였다. 최종 추시 시 봉합술을 시행한 예에서 I군의 경우 26예 중 22예$(85\%)$는 성공 판정을 받았으며, II군의 경우 3예 중 2예$(67\%)$에서 성공 판정을 받았고, 절제술을 시행한 예에서는 I군의 경우 26예 중 전예에서 II군의 경우 28예 중 26예$(93\%)$에서 성공 판정을 받았다. 이중 I군에서 재수술을 시행한 경우가 봉합술을 시행한 2예에서 있었고, 재수술 당시 1예에서는 봉합부위의 재파열과 다른 1예에서는 새로운 부위의 파열을 발견하였다. II군에서는 원판형 연골의 모양을 보였던 19예 중 2예에서 절제술 후 남아있는 연골에서 새로운 파열이 발견되었다. 결론 : 내측과 외측 반월상연골의 전위된 양동이 손잡이형 파열에 있어 동반 손상이 현저히 다르며, 그 차이를 고려하는 것이 적절한 치료 원칙을 정하는데 도움이 되리라 사료된다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제28권5호
• /
• pp.404-416
• /
• 2006

Purpose : This study was to clarify the changes in mandibular condyle after unilateral mandibular distraction osteogenesis throughout histological changes and expression of matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2). Materials & Methods : Intraoral distractors were placed via submandibular incision in 8 dogs. Two unoperated animals served as controls. Distraction was performed five days after osteotomy as a rate of 0.5 mm twice per day for 10 days. Two animals were sacrificed on 7, 14, 28, and 56 days after completion of distraction, respectively. Ipsilateral condyles were harvested and processed for histological and immunohistochemical examinations. Results : The condyle cartilage is separated into four layers: fibrous layer, proliferative layer, hypertrophic layer, and calcified layer. At 7 days and 14 days after distraction, the condylar cartilage showed the decreased thickness of the articular cartilage and reduced cellularity. At 28 days after distraction, there was an increase in cellularity of fibrous, proliferative, and hypertrophic layer. However, it demonstrated reduced cellularity compared to the control. At 56 days of after distraction, the articular cartilage was an almost normal histologic structure. Positive Safranin-O staining, indicative of sulfated proteoglycans, was examined in the condylar cartilge of nonloaded control. At 7 days and 14 days after distraction, the sulfated proteoglycans is almost completely depleted from the noncalcified part of the condylar cartilage. At 28 days after distraction, there was an increase in Safranin-O staining intensity. However, the staining intensity of the experimental condyle was weaker than that of the control. At 56 days of after distraction, the condylar cartilage showed almost normal Safranin-O staining pattern. In control condyle, MMP-2 immunostaining was seen in fibrous, proliferative, and hypertrophic layer of condylar cartilage, however, it demonstrated lack of staining in fibrous and proliferative layer. At 7 days and 14 days after distraction, strong MMP-2 immunoreactivity was seen in the fibrous, proliferative and hypertrophic layer of the condylar cartilage. At 28 days after distraction, MMP-2 immunostaining was seen in the fibrous and hypertrophic layer of condylar cartilage, however, their immunoactivity was reduced. At 56 days after distraction, MMP-2 immunoreactivity showed almost normal immunostaining pattern. In control condyle, TIMP-2 immunostaining was primarily seen in fibrous and hypertrophic layer of condylar cartilage, however, it demonstrated lack of staining in proliferative layer. At 7 days after distraction, very weak TIMP-2 immunoreactivity appeared in fibrous, proliferative and hypertrophic layer of the condylar cartilage. At 14 days after distraction, weak TIMP-2 immunoreactivity was seen in the fibrous, proliferative and hypertrophic layer of the condylar cartilage. At 28 days after distraction, TIMP-2 immunoreactivity was increased in the fibrous and hypertrophic layer of condylar cartilage. At 56 days after completion of distraction, TIMP-2 immunoreactivity showed almost normal immunostaining pattern. Conclusions : The results show that short-term outcome of physiologic distraction osteogenesis may lead to degenerative changes in the condylar cartilage. These alterations in the condylar cartilage may be considered as a pressure-related degeneration of the cartilage tissue. However, the long-term results suggest that the condylar cartilage display repair activity after mandibular distraction osteogenesis.

• Asian Pacific Journal of Cancer Prevention
• /
• 제17권9호
• /
• pp.4517-4525
• /
• 2016

Background: Sperm DNA damage is underlying aetiology of poor implantation and pregnancy rates but also affects health of offspring and may also result in denovo mutations in germ line and post fertilization. This may result in complex diseases, polygenic disorders and childhood cancers. Childhood cancer like retinoblastoma (RB) is more prevalent in developing countries and the incidence of RB has increased more than three fold in India in the last decade. Recent studies have documented increased incidence of cancers in children born to fathers who consume alcohol in excess and tobacco or who were conceived by assisted conception. The aetiology of childhood cancer and increased disease burden in these children is lin ked to oxidative stress (OS) and oxidative DNA damage( ODD) in sperm of their fathers. Though several antioxidants are in use to combat oxidative stress, the effect of majority of these formulations on DNA is not known. Yoga and meditation cause significant decline in OS and ODD and aid in regulating OS levels such that reactive oxygen speues meditated signal transduction, gene expression and several other physiological functions are not disrupted. Thus, this study aimed to analyze sperm ODD as a possible etiological factor in childhood cancer and role of simple life style interventions like yoga and meditation in significantly decreasing seminal oxidative stress and oxidative DNA damage and thereby decreasing incidence of childhood cancers. Materials and Methods: A total of 131 fathers of children with RB (non-familial sporadic heritable) and 50 controls (fathers of healthy children) were recruited at a tertiary center in India. Sperm parameters as per WHO 2010 guidelines and reactive oxygen species (ROS), DNA fragmentation index (DFI), 8-hydroxy-2'-deoxy guanosine (8-OHdG) and telomere length were estimated at day 0, and after 3 and 6 months of intervention. We also examined the compliance with yoga and meditation practice and smoking status at each follow-up. Results: The seminal mean ROS levels (p<0.05), sperm DFI (p<0.001), 8-OHdG (p<0.01) levels were significantly higher in fathers of children with RB, as compared to controls and the relative mean telomere length in the sperm was shorter. Levels of ROS were significantly reduced in tobacco users (p<0.05) as well as in alcoholics (p<0.05) after intervention. DFI reduced significantly (p<0.05) after 6 months of yoga and meditation practice in all groups. The levels of oxidative DNA damage marker 8-OHdG were reduced significantly after 3 months (p<0.05) and 6 months (p<0.05) of practice. Conclusions: Our results suggest that OS and ODD DNA may contribute to the development of childhood cancer. This may be due to accumulation of oxidized mutagenic base 8OHdG, and elevated MDA levels which results in MDA dimers which are also mutagenic, aberrant methylation pattern, altered gene expression which affect cell proliferation and survival through activation of transcription factors. Increased mt DNA mutations and aberrant repair of mt and nuclear DNA due to highly truncatred DNA repair mechanisms all contribute to sperm genome hypermutability and persistant oxidative DNA damage. Oxidative stress is also associated with genome wide hypomethylation, telomere shortening and mitochondrial dysfunction leading to genome hypermutability and instability. To the best of our knowledge, this is the first study to report decline in OS and ODD and improvement in sperm DNA integrity following adoption of meditation and yoga based life style modification.This may reduce disease burden in next generation and reduce incidence of childhood cancers.

• Journal of Preventive Medicine and Public Health
• /
• 제32권1호
• /
• pp.101-107
• /
• 1999

Objectives. To determine the effects of exposure to hexavalent chromium, 93 male Sprague-Dawley rats were exposed to hexavalent chromium solution. Methods. Rats were divided into 4 groups and exposed to 0.1ml of 0 mM, 0.4 mM, 2.0 mM, and 10.0 mM potassium chromate in the first experiment, and to 0.1 ml of 0 mM, 20 mM, 40 mM, and 80 mM in the second for consecutive 3 days by tracheal instillation. Three and 10 rats were the controls for the first and the second experiments, respectively. Lung tissues were then removed to measure the 8-hydroxydeoxyguanosine (8-OH-dG) level using the HPLC-ECD method, superoxide dismutase (SOD) activity using the cytochrome C method, and 8-hydroxyguanine endonuclease activity using the oligonucleotide nicking assay. Results. The results showed no significant linear relationship between chromium exposure level and 8-OH-dG level or 8-hydroxyguanine endonuclease activity. In the first experiment, 8-OH-dG level and 8-hydroxyguanine endonuclease activity increased in 0.4 mM group, and then decreased in 2.0 mM and 10.0 mM groups. The correlation coefficients between 8-OH-dG level and 8-hydroxyguanine endonuclease activity was statistically significant (P<0.01), and total SOD activity was elevated by chromium exposure in a dose-dependent manner (P<0.05). In contrast, there was no significant dose-response pattern or correlation in the secod experiment. Conclusions. Based on the fact that there was no linear relationship between chromium dose and 8-OH-dG level or activity of the repair enzyme, it seems unlikely that 8-OH-dG formation is the major mechanism of chromium carcinogenesis.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제38권
• /
• pp.25.1-25.4
• /
• 2016

Background: Bilateral sagittal split ramus osteotomy (BSSRO) is the most widely used mandibular surgical technique in orthognathic surgery and is easy to relocate the distal segments, accelerating bone repair by the large surface of bone contact. However, it can cause neurosensory dysfunction (NSD) or sensory loss by injury of the inferior alveolar nerve. The purpose of the present study was to evaluate NSD after BSSRO and modifiers at NSD recovery. Methods: In this study, NSD characteristics after BSSRO from 2009 to 2014 at the Kyung Hee University Dental Hospital were evaluated. The pattern of sensory recovery over time was also evaluated based on factors such as field of sensory dysfunction, surgical procedure, presence of pre-operative facial asymmetry, and postoperative medications. Results: Most of the patients had shown NSD immediately after orthognathic surgery. Among the 1192 sides of 596 patients, NSD was observed in 953 sides and 544 patients. Sexual predilection was shown in males (p value = 0.0062). In the asymmetric group of 132 patients, NSD was observed in 128 patients (96.97 %). In the symmetric group of 464 patients, NSD was observed in 416 patients (89.45 %); on the other hand, NSD was observed significantly higher in the asymmetric group (p = 0.025). NSD-associated factors were analyzed, and vitamin B12 may be beneficial for NSD recovery. Conclusions: There was a difference between the symmetric group and the asymmetric group in NSD recovery. Vitamin B12 can be regarded as an effective method to nerve recovery. However, a further prospective study is needed.