• 제목/요약/키워드: resistance level

검색결과 2,251건 처리시간 0.032초

Titanium Implant의 Removal Torque에 관한 연구 (A STUDY ON THE REMOVAL TORQUE OF TITANIUM IMPLANTS)

  • 이준석;김영수;김창회
    • 대한치과보철학회지
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    • 제32권1호
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    • pp.148-169
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    • 1994
  • The concept of biologic attachment of load-bearing implants has developed over the past decades as an alternative to the difficulties associated with long term implantation using mechanical fixation and bone cement. The choice of implant material is also as critical an element as site preparation or insertion procedure. The properties of implants that affect host tissue responses are not limited to chemical composition alone, but also include shape, surface characteristics, site of implantation, and mechanical interaction with host tissues. Initial mechanical interlocking prevents micromotion and may be a prerequisite for direct bone apposition. A hard tightening of screws does not necessarily mean a stronger fixation and final tightening of the fixtures is dependent on the experience of the operator. Removal torque is lower than insertion torque. The purpose of this study was to investigate differences in the removal torques at the bone-implant interface of polished and sandblasted Titanium. This experiment will give insight into important factors that must be considered when interpreting in vivo screwing forces on implants during the connection of the transmucosal abutments. We evaluated the significance of different surface textures by comparison of the withdrawal forces necessary for removal of otherwise identical rough and polished implants of Titanium and also evaluated interfacial response on the light microscopic level to implant surface. And the priority of the area of insertion on osseointegration were evaluated. 9 Titanium implants - among them, 3 were for the developmental - of either a smooth or rough surface finish were inserted in the dog mandible in the right side. 3 months later Kanon Torque Gauge was used to unscrew the implants. The results were as follows : 1. No significant difference was seen in the removal torque due to variation in surface treatment, 23 Ncm for the sandblasted and 23.33 Ncm for the polished surface (p>0.05). 2. Implants in the anterior (25 Ncm) mandible showed better resistance to unscrewing in comparison to ones in the posterior (18 Ncm) region (p<0.05). 3. Developmental fixtures (22 Ncm) had similar pullout strength to the control group (p>0.05).

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사회운동조직의 사회복지제도화와 미시저항 -지역자활센터의 사례를 중심으로- (The History of Conflicts between Social Movements and Social Welfare -A Case Study of Self-Sufficiency Promotion Centers in South Korea-)

  • 김수영
    • 한국사회복지학
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    • 제65권2호
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    • pp.255-285
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    • 2013
  • 본 논문은 자활사업을 주요사례로 정부의 사회복지사업에 민간파트너로 참여하고 있는 사회운동조직이 어떻게 전문 사회복지기관과의 역학관계 속에서 자신의 자발적 정체성을 방어해나가는지 살펴보고자 한다. 군부독재가 막을 내리고 민주화와 진전되면서 과거 정부와 대립하던 사회운동단체들이 복지정책의 주요파트너로 부상했다. 저소득층의 일자리 지원사업인 자활사업도 빈민 실업운동진영과의 협력으로 도입된 복지제도이다. 그러나 사회운동에 대한 기존연구들은 사회운동조직이 제도화되면서 자발성이 훼손되고 사회복지 전문가와 기관들에게 헤게모니를 내놓게 된다고 지적해왔다. 이에 본 연구는 자활사업 관련 역사문헌, 심층면접, 참여관찰 자료에 대한 역사적 담론 분석을 통해, 자활사업의 도입시기부터 현재까지 사회운동조직의 자활사업 내 입지변화와 운동조직이 일선현장에서 사회복지진영으로부터 자신을 구별하기 위해 각 국면마다 구사해온 담론과 전략들이 있는지 추적했다. 본 논문은 사회운동과 사회복지의 갈등의 역사 속에서 사회운동진영의 생존전략들을 살펴봄으로써, 사회운동의 사회복지제도화와 전문화를 단지 사회운동의 지배체계로의 편입, 흡수, 종속으로 설명할 수 없고, 그 이면에 사회운동조직의 미시저항이 존재함을 드러내고자 했다.

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Gender Differences in Physiological Effects of a Transient Exposure to Experimental Noise

  • ;;;;최석철
    • 대한의생명과학회지
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    • 제12권4호
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    • pp.375-383
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    • 2006
  • The physiological responses following stress are different in individual or personality. We performed this study to clarify gender differences in influences of noise stress on physiological factors. 70 healthy subjects, which was divided man (n=30) and woman (n=40) groups, were exposed to 85 decibels of excavator noise for 15 minutes. Cardiac factors such as heart rate (HR), systolic and diastolic blood pressures (SBP and DBP, respectively), and heart rate-systolic pressure product (RPP) were determined. Transcranial Doppler ultrasound (TCD) was used to measure mean blood flow velocity (Vm), pulsatility index (PI), and resistance index (RI) in the middle, anterior and posterior cerebral arteries (MCA, ACA and PCA, respectively) before and during noise exposure. Cortisol level and hematological variables were also measured before (baseline) and immediately after the end of noise exposure. In the both groups HR, SBP, and RPP significantly decreased during noise exposure (P<0.05) but not significantly different between two groups (P>0.05). Vms of three cerebral arteries in man group decreased, whereas Vm of PCA in woman group fell during noise exposure (P<0.05). Vm, PI and RI in MCA and ACA during noise exposure were low in man group compared with woman group (P<0.05). Vm of PCA was low, whereas PI and RI of PCA were high in man group compared with woman group during noise exposure (P<0.05). Total leukocyte and red blood cell (RBC) counts slightly decreased during noise exposure but not significant (P>0.05). Levels in hematological variables decreased but not significant changed following noise exposure. Decreased rate of total leukocyte in man group was higher (P<0.05). Cortisol levels in the both groups decreased immediately after the end of noise exposure, while the decreased rate in man group was greater than that in woman group (p<0.05). These findings indicate that a transient exposure to experimental excavator noise may cause decreased changes in cardiac factors, cerebral hemodynamics and cortisol levels and the changes may be greater in men than in women.

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종이 의상에 관한 연구 - 수제지를 중심으로 - (A Study on the Paper Clothing -on the basis of handmade paper-)

  • 이주실;김정혜
    • 복식
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    • 제44권
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    • pp.181-199
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    • 1999
  • The industry of modern clothing has deviated from the overflow of commercialism and the standardization and nowadays is going toward pursuing art, creativity, and high added value. This trend brings the return of the natural materials from the synthetic textiles and increases the value of old and handmade fabrics. Finally, the handmade-paper, which is a natural material, comes to be reconsidered as a new material for the clothing. Therefore, as the natural materials and the manufacture of handmade clothing are rising again, the qualitative improvement and globalization of clothing industry should be first realized through the developments of creative and various clothing materials and new expressing techniques. The above investigation and study have been synthesized and analyzed as follows: First, through the study on the origin of the paper clothing, its historical background and the process of its development, we've learned these two facts following : the paper clothing of the East in the past mostly had practiced meanings. On the other hand, in the West it had meanings which were raised the artist's emotions and beauty-consciousness to the artistic level by the various kinds of expressing methods. Second, handmade-paper was manufactured by the embedding method, which mixed mulberry pulp, gauze, corn, hair, sisal, silk and so on. It was found that handmade-paper had the affluent and proper texture as the clothing material and was be able to control the clarity through the variation of thickness. It was also confirmed that the creative and original texture with hand-worked molding beauty was obtained by the use of handmade-paper. Third, when the handmade-paper is used, the molding beauty of plane, relievo, and solid can be freely pursued, and various and effective molding conformation can be constructed by the effect of superposition and repetition. Also, because the maximum discretion from the various optional manufacturing methods is allowed, the molding beauty can be maximized when the clothes are manufactured with handmade-paper. Fourth, the gauze with strong drape was combined to overcome the stiffness and the tearing of the paper. As a result, the durability and the wearability of the paper were strengthened and thus the thus the applications as the clothing material were enlarged. In conclusion, in order to enhance the value, creativity, practicality, and artistic sense of the design for modern clothing, the clothes made of handmade-paper should be more studied. Moreover, for the generalization of paper clothes, the studies on the development of practical paper with paper with water resistance, post-treatment after dyeing, flexibility, and durability should be done. I really hope that this study will be the motive to provoke the possibility of handmade-paper as new clothing material in not only practical sense but also artistic sense.

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나이와 성별에 따른 지역사회 거주 노인에서 무증상 경동맥 죽상경화증에 대한 혈관위험인자 및 인지장애와의 관련성 (Age and Gender Differences in the Relationship of Cognitive Impairment, Vascular Risk Factors, and Subclinical Carotid Atherosclerosis from Community-based Elderly)

  • 김지희;박현영;김대원;변승재;문효정;이인;양충용
    • 동의생리병리학회지
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    • 제26권3호
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    • pp.399-407
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    • 2012
  • To evaluate age and gender differences in the relation of cardiovascular risk factors, cognitive impairment, and subclinical carotid atherosclerosis from aged people using by a cross sectional method. Sixty-nine healthy elders living in the community who had not previously undergone carotid ultrasonography were included. We conducted life style surveys, and cognitive function tests including Korean-mini-mental state examination (K-MMSE) and clinical dementia rating-Korean. Various biomarkers from blood were assessed; fasting insulin-like growth factor-1, lipid-profile, high sensitivity C-reactive protein, total homocysteine, glucose, insulin, Homeostasis model assessment (HOMA) for insulin resistance index, vitamin B12, and folate level. Carotid intima-media thickness (C-IMT), and plaques were measured using carotid ultrasonography and aortic ultrasonography, a valid index of atherosclerosis. For the elderly subjects (aged 65-82 years), cognition impairment was more prevalent in females while subclinical atherosclerosis was more prevalentin males. Increased C-IMT has been kept in males, and C-IMT shows increasing trend and the peak at about 80 year-old in females with increasing age. The significant correlations between C-IMT and many vascular risk factors including age, triglyceride, abnormal homocysteinein male, and K-MMSE, insulin, HOMA index and abnormal aortic ultrasonography in female were different in each gender, with the exception of homocysteine (p<0.05). This data suggests that there were differences of age and gender characteristics in terms of subclinical atherosclerosis, cognitive impairment and vascular risk factors in community-living elders. Further larger and longitudinal studies across entire age are required to better understand the effects of risk factors on subclinical atherosclerosis.

폐쇄성 요로병증에서 $17{\beta}$-estradiol에 의한 신섬유화 감소 효과에 대한 연구 ($17{\beta}$-estradiol Attenuates Renal Fibrosis in Mice with Obstructive Uropathy)

  • 조민현;장희성;정경진;박권무
    • Childhood Kidney Diseases
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    • 제15권2호
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    • pp.125-137
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    • 2011
  • 목적: 일반적으로 남자는 여자에 비해 만성 신장병의 발병이 많고 말기 신부전으로의 진행이 더 흔한 것으로 알려져 있다. 본 연구는 일측성 요관 폐쇄를 가진 생쥐에서 신섬유화에 대한 성별과 성호르몬의 효과를 규명하기 위해 시행되었다. 방법: 일측성 완전 요관 폐쇄 7일째 암컷과 수컷 생쥐의 신장에서 ${\alpha}$-smooth muscle actin (${\alpha}$-SMA)의 발현을 측정한 후, 암컷 생쥐에서 난소를 제거하거나 제거 후 다시 $17{\beta}$-estradiol을 보충하여 나타나는 신섬유화 정도를 비교 분석하였다. 결과:일측성 요관 폐쇄를 가진 암컷 신장의 ${\alpha}$-SMA의 발현이 수컷 신장에 비해 현저히 낮았다. 난소 제거와 $17{\beta}$-estradiol의 보충은 일측성 요관 폐쇄를 가진 암컷 신장의 안지오텐신 II 1형 수용체의 발현에는 의미 있는 영향을 주지 않았지만, 안지오텐신 II 2형 수용체의 발현은 정상 암컷과 난소 제거 후 $17{\beta}$-estradiol를 보충한 암컷에서 현저히 증가되었다. 또한, inducible nitric oxide synthase (iNOS) 역시 유사한 변화를 보였다. 결론 : 여성은 폐쇄성 요로병증에서 신섬유화에 대한 저항성과 연관이 있으며 이러한 성별의 차이는 $17{\beta}$-estradiol에 의한 안지오텐신 II 2형 수용체와 iNOS의 발현 증가와 연관이 있을 것으로 사료된다.

구충성빈혈(鉤蟲性貧血)에 관(關)한 연구(硏究) (The Study on the Ferrokinetics and Acquired Immunity in Repeated Hookworm Infections)

  • 이문호;이필웅
    • 대한핵의학회지
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    • 제1권2호
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    • pp.61-74
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    • 1967
  • In order to confirm whether acquired immunity or resistance can be developed by the repeated hookworm infections, the 150 mature actively moving filariform ancylostoma duodenale larvae obtained from the severe hookworm anemia patients were orally given to 8 healthy volunteers in three divided doses, 50 in each, at 5 day interval. Also the hematological changes as well as several ferrokinetics using $^{59}Fe$ were done and were compared with 10 controls. The clinical symptoms and signs were checked every day for the first 3 weeks and then twice weekly until the end of the experiment. The appearance of the ova in the stool was examined by the formalin ether method and the ova was counted by the Stoll's method. The following laboratory tests were done: 1) Red blood cell count, venous blood hematocrit(micromethod), hemoglobin count (cyanomethemoglobin method) were checked every 5 to 7 day interval. 2) Plasma iron concentration (Barkan's modified method) was determined every 2 to 3 week interval. 3) Radioisotope studies: a) Ferrokinetics: Huff et al and Bothwell's method were applied. Erythropoietic Index (% of normal)=$\frac{Subject's\;turnover/100ml\;whole\;blood{\times}100}{Average\;normal\;turnover/100ml\;whole\;blood}$ of the gastrointestinal absorption of iron: Radioiron($^{59}Fe$) balance b) Quantitative measurement method was applied. c) Determination of the plasma erythropoietin activity: Fried's method was applied. Following were the results: 1) The serum iron level was lower. The red cell volume was decreased, but with relative increase of plasma volume. 2) The plasma iron disappearance time was accelerated and the plasma iron turnover rate was decreased. The red cell iron turnover rate was markedly increased, while all of the red cell iron concentration, circulating red cell iron. plasma iron pool were decreased. The daily iron pool turnover and red cell renewal rate were increased. 3) The erythropoietic index, erythropoietin activity and intestinal absorption of iron($^{59}Fe$) were markedly increased. 4) The infectivity was $9.8{\pm}1.31%$ which was lower than that observed in the single infection. 5) From these observations, it is concluded that the hookworm anemia is essentially iron deficieny in its origin and some immunity acquisition is possible with repeated infections.

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저온 상변화 물질 특성을 이용한 태양열 물펌프 실용화 연구개발(II) ­시스템 구성 및 작동분석 (Development of a Solar Powered Water Pump by Using Low Temperature Phase Change Material ­ System Construction and Operation Analysis ­)

  • 김영복;이양근;이승규;김성태;나우정;민영봉
    • 한국축산시설환경학회지
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    • 제9권2호
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    • pp.69-78
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    • 2003
  • 태양열을 동력원으로 하여 열에너지를 동력으로 변환, 물을 양수할 목적으로 저온 상변화물질인 펜탄을 작동물질로 하는 에너지변환장치를 제작하여 실험하였다. 장치는 각부의 크기를 그 기능과 상호작용 원리에 따라 논리에 맞게 최적 설계하였다. 장치의 제작 후 실험을 통하여 그 운전 특성을 분석하여 성능향상에 필요한 자료를 획득하고자 하였다. 작동물질인 펜탄을 가열하는 탱크 내부의 온도는 사이클 경과시간에 따라 약 $40­86^{\circ}C$ 범위에서 변동하고 있었으며, 물탱크내 온도 약 $23­24^{\circ}C$, 공기탱크 내 온도 $22­23.5^{\circ}C$ 범위에서 비교적 일정하게 유지되고 있었다. 응축기내의 온도와 냉각수출구 온도는 냉각수입구 온도수준에 따라 정의 상관관계로 변하고 있는 것을 알 수 있었으며, 또한 열 교환 능력도 냉각수 온도수준이 낮을수록 커진다는 것을 확인하였다. 물탱크 내 온도와 응축기내 온도가 상당히 차이가 나므로 물탱크와 응축기와의 연결거리를 최소화하고 연결파이프 크기를 큰 것으로 하여 내부물질이동 저항을 줄이는 것이 바람직하다는 것을 알 수 있었다. 실험 중 양수량은 1.6­2.4 liter로 나타났으며, 냉각시간의 수준에 따른 물탱크내의 흡입물높이 상승은 차이를 나타내지 않았다. 응축기로부터의 냉각수 배출파이프가 연장되지 않은 경우 냉각수 유량이 5.9 liter/min 이었으나 연장파이프가 있을 때는 2.3 liter/min으로 나타났다. 이러한 현상에서 양수하는 물의 온도가 낮고 유량이 부족한 경우에는 연장파이프를 이용하는 것이 좋고, 냉각수치 양은 풍부하지만 그 온도가 낮지 않은 경우에는 연장파이프를 이용하지 않는 것이 좋다는 사실을 알 수 있다. 실험에서의 응축기내 냉각수의 최대 열교환량은 95.75 kJ/min로 나타났다. 작동물질가열탱크와 기액 분리탱크 내의 압력은 0.13­0.14 MPa.a, 물탱크와 응축기내의 압력은 약 0.11 MPa.a정도로 나타났다.

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Time - and Concentration - Dependent Effects of Resveratrol on miR 15a and miR16-1 Expression and Apoptosis in the CCRF-CEM Acute Lymphoblastic Leukemia Cell Line

  • Azimi, Ako;Hagh, Majid Farshdousti;Talebi, Mehdi;Yousefi, Bahman;feizi, Abbas Ali Hossein pour;Baradaran, Behzad;Movassaghpour, Ali Akbar;Shamsasenjan, Karim;Khanzedeh, Taghi;Ghaderi, Abdol Hasan;Heydarabad, Milad Zadi
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권15호
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    • pp.6463-6468
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    • 2015
  • Background: Chemotherapy is one of the common approaches in treatment of cancers, especially leukemia. However, drug resistance phenomena reduce the likelihood of treatment success. Resveratrol is a herbal compound which through complicated processes makes some selected cells sensitive to treatment and induction of apoptosis. In the present study, the effects of resveratrol on the expression of miR 15a and miR16-1 and apoptosis in the CCRF-CEM cell line were investigated. Materials and Methods: The CCRF-CEM cell line was cultured under standard conditions and changes in miR 15a and miR 16-1 expression were analyzed by real time-PCR technique, with attention to reveratrol dose and time dependence. Also, apoptosis is evaluated by flow cytometry using annexin V and PI. Results: CCRF-CEM cells underwent dose-dependent apoptotic cell death in response to resveratrol. MiR 15a and miR 16-1 expression was up-regulated after 24 and 48 hours resveratrol treatment (p<0.05). Conclusions: The results of our study indicate that resveratrol induces apoptosis in a time and dose-dependent manner in CCRF-CEM cells. Also, increased expression level of miR 16-1 and miR 15a by means of resveratrol in CCRF-CEM cells might have a role in apoptosis induction and predisposition. According to our results resveratrol can be regarded as a dietary supplement to improve efficacy of anti-leukemia therapies.

Knockdown of Ezrin by RNA Interference Reverses Malignant Behavior of Human Pancreatic Cancer Cells in Vitro

  • Zhong, Zhi-Qiang;Song, Mao-Min;He, Ying;Cheng, Shi;Yuan, Hui-Sheng
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권8호
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    • pp.3781-3789
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    • 2012
  • Background: Pancreatic cancer is one of the most aggressive tumors with a dismal prognosis. The membrane cytoskeletal crosslinker Ezrin participates in several functions including cell proliferation, adhesion, motility and survival. There is increasing evidence that Ezrin is overexpressed in vast majority of malignant tumors and regulates tumor progression. However, its roles in pancreatic cancer remain elusive. Methods: Three pairs of specific Ezrin siRNAs were designed and synthetized and screened to determine the most efficient one for construction of a hairpin RNA plasmid targeting Ezrin. After transfection into the Panc-1 pancreatic cancer cell line, real-time quantitative PCR and Western blotting were performed to examine the expression of mRNA and protein. The MTT method was applied to examine the proliferation and the drug sensibility to Gemcitabine. Flow cytometry was used to assess the cycle and apoptosis, while capacity for invasion was determined with transwell chambers. Furthermore, we detected phosphorylated-Erk1/2 protein and phosphorylated-Akt protein by Western blotting. Results: Real-time quantitative PCR and Western blotting revealed that Ezrin expression was notably down-regulated at both mRNA and protein levels by RNA interference (P< 0.01). Proliferation was inhibited and drug resistance to gemcitabine was improved (P< 0.05). Flow cytometry showed that the proportion of cells in the G1/G0 phase increased (P< 0.01), and in G2/M and S phases decreased (P< 0.05), with no apparent differences in apoptosis (P> 0.05). The capacity for invasion was markedly reduced (P< 0.01). In addition, down-regulating Ezrin expression had no effect on phosphorylated-Akt protein (P>0.05), but could decrease the level of phosphorylated-Erk1/2 protein (P< 0.05). Conclusions: RNA interference of Ezrin could inhibit its expression in the pancreatic cancer cells line Panc-1, leading to a potent suppression of malignant behavior in vitro. Assessment of potential as a target for pancreatic cancer treatment is clearly warranted.