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  1. Article ; Online: Immature bovine cartilage wear is due to fatigue failure from repetitive compressive forces and not reciprocating frictional forces.

    Petersen, C A / Sise, C V / Dewing, J X / Yun, J / Zimmerman, B K / Guo, X E / Hung, C T / Ateshian, G A

    Osteoarthritis and cartilage

    2023  Volume 31, Issue 12, Page(s) 1594–1601

    Abstract: Objective: Wear of articular cartilage is not well understood. We hypothesize that cartilage wears due to fatigue failure in repetitive compression instead of reciprocating friction.: Design: This study compares reciprocating sliding of immature ... ...

    Abstract Objective: Wear of articular cartilage is not well understood. We hypothesize that cartilage wears due to fatigue failure in repetitive compression instead of reciprocating friction.
    Design: This study compares reciprocating sliding of immature bovine articular cartilage against glass in two testing configurations: (1) a stationary contact area configuration (SCA), which results in static compression, interstitial fluid depressurization, and increasing friction coefficient during reciprocating sliding, and (2) a migrating contact area configuration (MCA), which maintains pressurization and low friction while producing repetitive compressive loading in addition to reciprocating sliding. Contact pressure, sliding duration, and sliding distance were controlled to be similar between test groups.
    Results: SCA tests exhibited an average friction coefficient of μ=0.084±0.032, while MCA tests exhibited a lower average friction coefficient of μ=0.020±0.008 (p<10
    Conclusions: The greatest wear was observed in the group with lowest friction coefficient, subjected to cyclical instead of static compression, implying that friction is not the primary driver of cartilage wear. Delamination between superficial and middle zones implies the main mode of wear is fatigue failure under cyclical compression, not fatigue or abrasion due to reciprocating frictional sliding.
    MeSH term(s) Animals ; Cattle ; Friction ; Cartilage, Articular ; Extracellular Fluid ; Pressure ; Stress, Mechanical
    Language English
    Publishing date 2023-08-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 1167809-4
    ISSN 1522-9653 ; 1063-4584
    ISSN (online) 1522-9653
    ISSN 1063-4584
    DOI 10.1016/j.joca.2023.08.008
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: What is nanomechanics of bone and why is it important?

    Guo, X E

    Journal of musculoskeletal & neuronal interactions

    2008  Volume 8, Issue 4, Page(s) 327–328

    MeSH term(s) Animals ; Biomechanical Phenomena/physiology ; Bone and Bones/cytology ; Bone and Bones/physiology ; Humans ; Nanotechnology/trends
    Language English
    Publishing date 2008-10
    Publishing country Greece
    Document type Journal Article ; Review
    ZDB-ID 2041366-X
    ISSN 1108-7161
    ISSN 1108-7161
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Nanomechanics and bone tissue quality.

    Guo, X E

    Journal of musculoskeletal & neuronal interactions

    2008  Volume 8, Issue 4, Page(s) 325–326

    MeSH term(s) Animals ; Bone Density/physiology ; Bone and Bones/cytology ; Bone and Bones/physiology ; Humans ; Mechanotransduction, Cellular/physiology ; Nanotechnology/methods ; Nanotechnology/trends
    Language English
    Publishing date 2008-10
    Publishing country Greece
    Document type Introductory Journal Article
    ZDB-ID 2041366-X
    ISSN 1108-7161
    ISSN 1108-7161
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  4. Article: [Comparison of acquired immure deficiency syndrome-related knowledge and behavior between persons with and without human immunodeficiency virus- infection among young male students who have sex with men].

    Li, Y C / Cui, W X / Guo, X E / Zhu, F / Liu, S C / Jia, B B / Wang, P / Ma, Y H

    Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences

    2021  Volume 53, Issue 3, Page(s) 511–517

    Abstract: Objective: To understand the differences between young male students who have sex with men (MSM) with and without human immunodeficiency virus (HIV)-infection in acquired immure deficiency syndrome (AIDS)-related knowledge and behavior, and to provide a ...

    Abstract Objective: To understand the differences between young male students who have sex with men (MSM) with and without human immunodeficiency virus (HIV)-infection in acquired immure deficiency syndrome (AIDS)-related knowledge and behavior, and to provide a scientific reference to make targeted and effective measures in AIDS prevention.
    Methods: Using snow balling sampling combined with participants' referral, we conducted a questionnaire survey among 548 young MSM students (in whom there were both HIV-positive and HIV-negative) in Harbin, Tianjin, Xi'an, and Chongqing cities from April 2017 to March 2018. The chi-square test and binary Logistic regression were used to compare the differences in AIDS-related knowledge and behavior between males with and without HIV-infection.
    Results: A total of 583 questionnaires were obtained, of which 548 were valid, with an effective rate of 94.0%. Having a junior college education or below (
    Conclusion: There was no statistical difference between HIV positive and negative young MSM students in the cognition of "AIDS-related Knowledge for Public" and "AIDS-related Knowledge for Youth", which were both lower than 95% required by the state. However, the specificity in the knowledge needs was certainly shown. There was no significant difference in the recent sexual behavior between the two groups, but HIV positive students were more likely to have high-risk sexual behaviors in the early stage, so we should strengthen and move forward the sex education and AIDS prevention education with adjusted contents, and prevent high-risk sexual behaviors within young MSM students in the early stage.
    MeSH term(s) Adolescent ; HIV ; HIV Infections/epidemiology ; HIV Infections/prevention & control ; Health Knowledge, Attitudes, Practice ; Homosexuality, Male ; Humans ; Male ; Sexual Behavior ; Sexual and Gender Minorities ; Students ; Surveys and Questionnaires
    Language Chinese
    Publishing date 2021-06-19
    Publishing country China
    Document type Journal Article
    ZDB-ID 2452593-5
    ISSN 1671-167X
    ISSN 1671-167X
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Comprehensive Associations between Acidosis and the Skeleton in Patients with Kidney Disease.

    Levy, Rebecca V / McMahon, Donald J / Agarwal, Sanchita / Dempster, David / Zhou, Hua / Misof, Barbara M / Guo, X E / Kamanda-Kosseh, Mafo / Aponte, Maria Alejandra / Reidy, Kimberly / Kumar, Juhi / Fusaro, Maria / Brown, Denver D / Melamed, Michal L / Nickolas, Thomas L

    Journal of the American Society of Nephrology : JASN

    2023  Volume 34, Issue 4, Page(s) 668–681

    Abstract: Significance statement: Renal osteodystrophy (ROD) contributes substantially to morbidity in CKD, including increased fracture risk. Metabolic acidosis (MA) contributes to the development of ROD, but an up-to-date skeletal phenotype in CKD-associated ... ...

    Abstract Significance statement: Renal osteodystrophy (ROD) contributes substantially to morbidity in CKD, including increased fracture risk. Metabolic acidosis (MA) contributes to the development of ROD, but an up-to-date skeletal phenotype in CKD-associated acidosis has not been described. We comprehensively studied associations between acidosis and bone in patients with CKD using advanced methods to image the skeleton and analyze bone-tissue, along with biochemical testing. Cross-sectionally, acidosis was associated with higher markers of bone remodeling and female-specific impairments in cortical and trabecular bone quality. Prospectively, acidosis was associated with cortical expansion and trabecular microarchitectural deterioration. At the bone-tissue level, acidosis was associated with deficits in bone mineral content. Future work investigating acidosis correction on bone quality is warranted.
    Background: Renal osteodystrophy is a state of impaired bone quality and strength. Metabolic acidosis (MA) is associated with alterations in bone quality including remodeling, microarchitecture, and mineralization. No studies in patients with CKD have provided a comprehensive multimodal skeletal phenotype of MA. We aim to describe the structure and makeup of bone in patients with MA in the setting of CKD using biochemistry, noninvasive imaging, and histomorphometry.
    Methods: The retrospective cross-sectional analyses included 180 patients with CKD. MA was defined as bicarbonate ≤22 mEq/L. We evaluated circulating bone turnover markers and skeletal imaging with dual energy x-ray absorptiometry and high-resolution peripheral computed tomography. A subset of 54 participants had follow-up. We assessed associations between baseline and change in bicarbonate with change in bone outcomes. Histomorphometry, microCT, and quantitative backscatter electron microscopy assessed bone biopsy outcomes in 22 participants.
    Results: The mean age was 68±10 years, 54% of participants were male, and 55% were White. At baseline, acidotic subjects had higher markers of bone turnover, lower areal bone mineral density at the radius by dual energy x-ray absorptiometry, and lower cortical and trabecular volumetric bone mineral density and impaired trabecular microarchitecture. Over time, acidosis was associated with opposing cortical and trabecular effects: cortical expansion but trabecular deterioration. Bone-tissue analyses showed reduced tissue mineral density with increased heterogeneity of calcium distribution in acidotic participants.
    Conclusions: MA is associated with multiple impairments in bone quality. Future work should examine whether correction of acidosis improves bone quality and strength in patients with CKD.
    MeSH term(s) Male ; Female ; Humans ; Chronic Kidney Disease-Mineral and Bone Disorder/etiology ; Cross-Sectional Studies ; Retrospective Studies ; Bicarbonates ; Bone Density ; Radius ; Renal Insufficiency, Chronic/complications ; Renal Insufficiency, Chronic/pathology ; Acidosis/complications
    Chemical Substances Bicarbonates
    Language English
    Publishing date 2023-02-02
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1085942-1
    ISSN 1533-3450 ; 1046-6673
    ISSN (online) 1533-3450
    ISSN 1046-6673
    DOI 10.1681/ASN.0000000000000085
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: [The effect of Ba Duan Jin on the balance of community-dwelling older adults: a cluster randomized control trial].

    Duan, L L / Zhao, Y B / Er, Y L / Ye, P P / Wang, W / Gao, X / Deng, X / Jin, Y / Wang, Y / Ji, C R / Ma, X Y / Gao, C / Zhao, Y H / Zhu, S Q / Su, S Z / Guo, X E / Peng, J J / Yu, Y / Yang, C /
    Su, Y Y / Zhao, M / Guo, L H / Wu, Y P / Luo, Y N / Meng, R L / Xu, H F / Liu, H Z / Ruan, H H / Xie, B / Zhang, H M / Liao, Y H / Chen, Y / Wang, L H

    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi

    2024  Volume 45, Issue 2, Page(s) 250–256

    Abstract: Objective: ...

    Abstract Objective:
    MeSH term(s) Male ; Humans ; Female ; Aged ; Independent Living ; Exercise ; Health Education ; China
    Language Chinese
    Publishing date 2024-02-26
    Publishing country China
    Document type Randomized Controlled Trial ; English Abstract ; Journal Article
    ZDB-ID 645026-x
    ISSN 0254-6450
    ISSN 0254-6450
    DOI 10.3760/cma.j.cn112338-20230506-00283
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Abnormal microarchitecture and stiffness in postmenopausal women using chronic inhaled glucocorticoids.

    Liu, Y / Dimango, E / Bucovsky, M / Agarwal, S / Nishiyama, K / Guo, X E / Shane, E / Stein, E M

    Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

    2018  Volume 29, Issue 9, Page(s) 2121–2127

    Abstract: Postmenopausal (PM) women using inhaled glucocorticoids (IGCs) had substantial abnormalities in volumetric BMD (vBMD), microarchitecture, and stiffness using high resolution peripheral computed tomography (HRpQCT) compared to age- and race-matched ... ...

    Abstract Postmenopausal (PM) women using inhaled glucocorticoids (IGCs) had substantial abnormalities in volumetric BMD (vBMD), microarchitecture, and stiffness using high resolution peripheral computed tomography (HRpQCT) compared to age- and race-matched controls. Abnormalities were most severe at the radius. These preliminary results suggest that there may be major, heretofore unrecognized, skeletal deficits in PM women using IGCs.
    Introduction: While oral glucocorticoids are well recognized to have destructive skeletal effects, less is known about the effects of IGCs. The detrimental skeletal effects of IGCs may be greatest in PM women, in whom they compound negative effects of estrogen loss and aging. The goal of this study was to evaluate microarchitecture and stiffness in PM women using chronic IGCs.
    Methods: This case-control study compared PM women using IGCs for ≥ 6 months (n = 20) and controls matched for age and race/ethnicity (n = 60). Skeletal parameters assessed included areal BMD (aBMD) by DXA, trabecular and cortical vBMD and microarchitecture by HRpQCT of the radius and tibia, and whole bone stiffness by finite element analysis.
    Results: By DXA, mean values in both groups were in the osteopenic range; hip aBMD was lower in IGC users (P < 0.04). By HRpQCT, IGC users had lower total, cortical, and trabecular vBMD at both radius and tibia (all P < 0.05). IGC users had lower cortical thickness, lower trabecular number, greater trabecular separation and heterogeneity at the radius (all P < 0.03), and greater heterogeneity at the tibia (P < 0.04). Whole bone stiffness was lower in IGC users at radius (P < 0.03) and tended to be lower at the tibia (P = 0.09).
    Conclusions: PM women using IGCs had substantial abnormalities in vBMD, microarchitecture, and stiffness compared to controls. These abnormalities were most severe at the radius. These preliminary results suggest that there may be major, heretofore unrecognized, skeletal deficits in PM women using IGCs.
    MeSH term(s) Absorptiometry, Photon/methods ; Administration, Inhalation ; Aged ; Bone Density/drug effects ; Case-Control Studies ; Drug Administration Schedule ; Elasticity/drug effects ; Female ; Glucocorticoids/administration & dosage ; Glucocorticoids/adverse effects ; Glucocorticoids/pharmacology ; Humans ; Middle Aged ; Osteoporosis, Postmenopausal/chemically induced ; Osteoporosis, Postmenopausal/physiopathology ; Radius/physiopathology ; Tibia/physiopathology ; Tomography, X-Ray Computed
    Chemical Substances Glucocorticoids
    Language English
    Publishing date 2018-06-11
    Publishing country England
    Document type Journal Article
    ZDB-ID 1064892-6
    ISSN 1433-2965 ; 0937-941X
    ISSN (online) 1433-2965
    ISSN 0937-941X
    DOI 10.1007/s00198-018-4591-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Proteoglycans and mechanical behavior of condylar cartilage.

    Lu, X L / Mow, V C / Guo, X E

    Journal of dental research

    2009  Volume 88, Issue 3, Page(s) 244–248

    Abstract: Mandibular condylar cartilage functions as the load-bearing, shock-absorbing, lubricating material in temporomandibular joints. Little is known about the precise nature of the biomechanical characteristics of this fibro-cartilaginous tissue. We ... ...

    Abstract Mandibular condylar cartilage functions as the load-bearing, shock-absorbing, lubricating material in temporomandibular joints. Little is known about the precise nature of the biomechanical characteristics of this fibro-cartilaginous tissue. We hypothesized that the fixed charge density associated with proteoglycans that introduces an osmotic pressure inside condylar cartilage will significantly increase the tissue's apparent stiffness. Micro-indentation creep tests were performed on porcine TMJ condylar cartilage at 5 different regions-anterior, posterior, medial, lateral, and central-in physiologic and hypertonic solutions. The intrinsic and apparent mechanical properties, including aggregate modulus, shear modulus, and permeability, were calculated by indentation test data and the biphasic theory. The apparent properties (with osmotic effect) were statistically higher than those of the intrinsic solid matrix (without osmotic effect). Regional variations in fixed charge density, permeability, and mechanical modulus were also calculated for condylar surface. The present results provide important quantitative data on the biomechanical properties of TMJ condylar cartilage.
    MeSH term(s) Animals ; Biomechanical Phenomena ; Cartilage, Articular/anatomy & histology ; Cartilage, Articular/physiology ; Elastic Modulus ; Elasticity ; Fibrocartilage/physiology ; Hypertonic Solutions ; Lubrication ; Mandibular Condyle/anatomy & histology ; Mandibular Condyle/physiology ; Models, Biological ; Osmotic Pressure ; Permeability ; Proteoglycans/physiology ; Stress, Mechanical ; Swine ; Temporomandibular Joint/physiology ; Temporomandibular Joint Disc/physiology ; Weight-Bearing/physiology
    Chemical Substances Hypertonic Solutions ; Proteoglycans
    Language English
    Publishing date 2009-03-26
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 80207-4
    ISSN 1544-0591 ; 0022-0345
    ISSN (online) 1544-0591
    ISSN 0022-0345
    DOI 10.1177/0022034508330432
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: In vivo assessment of bone structure and estimated bone strength by first- and second-generation HR-pQCT.

    Agarwal, S / Rosete, F / Zhang, C / McMahon, D J / Guo, X E / Shane, E / Nishiyama, K K

    Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

    2016  Volume 27, Issue 10, Page(s) 2955–2966

    Abstract: Unlabelled: Bone strength is dependent on bone density and microstructure. High-resolution peripheral quantitative computed tomography (HR-pQCT) can measure microstructure but is somewhat limited due to its resolution. We compared a new HR-pQCT scanner ... ...

    Abstract Unlabelled: Bone strength is dependent on bone density and microstructure. High-resolution peripheral quantitative computed tomography (HR-pQCT) can measure microstructure but is somewhat limited due to its resolution. We compared a new HR-pQCT scanner to existing technology and found very good agreement for most parameters. This study will be important when interpreting results from different devices.
    Introduction: Recently, a second-generation HR-pQCT scanner (XCT2) has been developed with a higher nominal isotropic resolution (61 μm) compared to the first-generation device (XCT1, 82 μm). It is unclear how in vivo measurements from these two devices compare. In this study, we obtained and analyzed in vivo XCT1 and XCT2 measurements of bone microarchitecture and estimated strength.
    Methods: We scanned 51 adults (16 men and 35 women, age 44.8 ± 16.0) on both XCT2 and XCT1 on the same day. We first compared XCT1 and XCT2 measurements obtained using their respective standard patient protocols. In XCT1, microarchitecture parameters were derived, while XCT2 measurements were directly measured. We also compared XCT2-D with XCT1 by finding the overlapping regions of interest and using the standard patient protocol for XCT1.
    Results: We obtained excellent agreement between XCT1 and XCT2 for most of the volumetric bone mineral density (vBMD), trabecular and cortical measurements (All R (2) > 0.820) except for cortical porosity at the radius (R (2) = 0.638), trabecular number (R (2) = 0.694, 0.787) and trabecular thickness (R (2) = 0.569, 0.527) at both radius and tibia, respectively. XCT1 and XCT2-D measurements also had excellent agreement for most of the measurements (all R (2) > 0.870) except trabecular number (R (2) = 0.524, 0.706), trabecular thickness (R (2) = 0.758, 0.734) at both radius and tibia, respectively, and trabecular separation (R (2) = 0.656) at the radius.
    Conclusion: While some caution should be exercised for parameters that are more dependent on image resolution, results from our study indicate that second-generation scans can be compared to more widely available first-generation data and may be beneficial for multicenter and longitudinal studies using both scanner generations.
    Language English
    Publishing date 2016-10
    Publishing country England
    Document type Journal Article
    ZDB-ID 1064892-6
    ISSN 1433-2965 ; 0937-941X
    ISSN (online) 1433-2965
    ISSN 0937-941X
    DOI 10.1007/s00198-016-3621-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Correction to: Differences in bone quality and strength between Asian and Caucasian young men.

    Kepley, A L / Nishiyama, K K / Zhou, B / Wang, J / Zhang, C / McMahon, D J / Foley, K F / Walker, M D / Guo, X E / Shane, E / Nickolas, T L

    Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA

    2018  Volume 29, Issue 11, Page(s) 2581

    Abstract: The second name of the ninth author, X.E. Guo, was incorrectly coded as part of his surname. The publisher apologises for the inconvenience caused. ...

    Abstract The second name of the ninth author, X.E. Guo, was incorrectly coded as part of his surname. The publisher apologises for the inconvenience caused.
    Language English
    Publishing date 2018-08-28
    Publishing country England
    Document type Journal Article ; Published Erratum
    ZDB-ID 1064892-6
    ISSN 1433-2965 ; 0937-941X
    ISSN (online) 1433-2965
    ISSN 0937-941X
    DOI 10.1007/s00198-018-4684-5
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