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Bioengineering Conference, 2007. NEBC '07. IEEE 33rd Annual Northeast

Date 10-11 March 2007

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Displaying Results 1 - 25 of 164
  • Welcome Statement from the Conference Committee

    Publication Year: 2007 , Page(s): i
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  • Program Committee

    Publication Year: 2007 , Page(s): ii
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  • Conference Sponsors

    Publication Year: 2007 , Page(s): iii
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  • Keynote Session I

    Publication Year: 2007 , Page(s): iv - vii
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    Provides an abstract of the keynote presentation and a brief professional biography of the presenter. The complete presentation was not made available for publication as part of the conference proceedings. View full abstract»

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  • Schedule

    Publication Year: 2007 , Page(s): viii - x
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  • Table of contents

    Publication Year: 2007 , Page(s): xi - xxv
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  • Author index

    Publication Year: 2007 , Page(s): xxvi - xxxvii
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  • Copyright page

    Publication Year: 2007 , Page(s): xxxviii
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  • Retention of bone density and postural status with a non-invasive extremely low level mechanical signal: A ground based evaluation of efficacy

    Publication Year: 2007 , Page(s): 1 - 2
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (908 KB) |  | HTML iconHTML  

    In space, rapid losses in bone mineral density (BMD) leave astronauts at an increased risk of bone fracture. Longer microgravity missions combined with the lack of efficacy of current exercise regimes in reducing this loss leads to the need of a new treatment. This study has the goal of testing a treatment in the form of a low magnitude mechanical vibration. As an analog of space flight, 18 subjects spent 90 days in continuous 6 degree head down tilt, eight of which received 10 minutes of vibration treatment a day. Measurements of bone density and balance found that there was a 30-50% nonsignificant reduction in BMD loss in the hip, as well as a significant decrease in the loss of postural control. The combined factors of stronger bones and increased balance greatly reduce the risk of bone fracture. With a proposed multi-year planetary mission to Mars being planned by NASA, the need for improved musculoskeletal health is of increasing importance, and this device may provide the needed mode of increasing astronaut safety. View full abstract»

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  • Design of a reproducible murine femoral fracture device

    Publication Year: 2007 , Page(s): 3
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    Transgenic mouse models are commonly used to investigate bone healing and test new treatments before human trials. The objective of this project was to design and produce a fracture device to overcome previous limitations including a low reproducible transverse fracture rate, two user operation and poor consistency over time from spring use. This was accomplished by using an easily modifiable kinetic energy level, a novel Mouse Positioning System and an electromagnet assembly. The data collected from the validation experiment was used in the development of a constitutive relationship between kinetic energy and fracture type. This design may be useful to researchers as a more efficient solution for creating reproducible transverse fractures in mice. View full abstract»

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  • Dynamic loading of the shoulder during the Codman exercise

    Publication Year: 2007 , Page(s): 5 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (223 KB) |  | HTML iconHTML  

    Studies of biomechanical loading on proximal humerus fixation plates (PHP) have been limited to cadaveric models of non-uniform magnitudes of axial, bending, and torsional loads or static, physiological-like loading. The goal of this investigation was to develop an in vivo association between the dynamic loading on the shoulder joint with anatomic position to better understand PHP loading. The motion of the right arm and thorax during the performance of the Codman exercise of five healthy male volunteers was studied using an opto-electronic motion capture system. Time referenced angular joint positions were calculated using Euler angles, from which angular velocities and accelerations were derived, and the net shoulder moments were calculated using the anthropometry for elderly females (ges 60 yrs.). Results indicate that the PHP may experience minimal moment loads from medial/lateral arm rotations. The results also suggest that the Codman exercise may not be entirely active. View full abstract»

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  • Using a simplified marker configuration to determine the cardan angles of shoulder orientation

    Publication Year: 2007 , Page(s): 7 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1245 KB) |  | HTML iconHTML  

    Cardan angles are commonly used to represent clinically significant joint motions for simple movements such as those observed during gait. For motions involving large, three-dimensional, angular displacements, Gimbal locks occur and can produce erroneous Cardan angle results. This paper presents the results of an investigation to determine if Cardan angles can adequately predict complex shoulder orientations during manual hammering using a simplified opto-electronic marker configuration. A mechanical simulation of the simplified marker configuration was also constructed to test for known static and dynamic orientations and validate Cardan angle calculations. Results indicate that the simplified configuration is effective in tracking shoulder orientations in complex measurement scenarios involving limited marker placement choices. None of the rotation sequences were able to accurately and totally describe the entire anatomical range of shoulder motion during hammer usage. Results for the mechanical simulations were observed to describe shoulder orientations for simple, single-axis rotations less than or equal to 30". Single-axis rotation angles taken from different sequences were also observed to closely resemble actual motions. View full abstract»

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  • The characterization of Mustang in chondrogenesis in vitro

    Publication Year: 2007 , Page(s): 9 - 10
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1090 KB) |  | HTML iconHTML  

    The Musculoskeletal Temporally Activated Novel Gene (Mustang) was identified by suppressive subtractive hybridization comparing bone fracture callus to intact bone. Mustang's peak in expression (50-fold over intact levels) was localized temporally to early time points during the Bone Fracture Repair (BFR) process that correspond to proliferation of chondrocyte progenitor cells and chondrogenesis at the fracture site. Further, this small protein contains a nuclear localization sequence and spatially localized to proliferating chondrocytes within the adult rat knee joint. These data suggests that Mustang may act as a transcriptional co-activator or co-repressor. The elucidation of Mustang's expression during the proliferation and differentiation of chondrocytes in vitro could help shed light on Mustang's function. To this end, Mustang was over expressed by stable transfection and silenced via RNAi in the RCJ 5.18 chondrocytic cell line. The over expression of Mustang up to six-fold in the RCJ cells showed no significant effect on either cell growth or matrix production. However, reduction of Mustang expression by 52-66% resulted in both a significant decrease in proliferation rate as well as diminished matrix production. This suggests that Mustang is necessary for chondrocyte proliferation as well as differentiation and possibly functions as a regulator of chondrogenesis. View full abstract»

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  • Enhanced bone formation around dental implant using electrical stimulation

    Publication Year: 2007 , Page(s): 11 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1143 KB) |  | HTML iconHTML  

    It has been known that electrical stimulation promotes osteogenesis. Electrical stimulation using direct current can be applied to dental implant without invasive technique. The purpose of study was to evaluate the effect of biphasic direct current (BDC) on osteoblast in vitro and on early bone formation around implant. Human mesenchymal stem cells were exposed to BDC (1.5 A/cm2, 1,000 Hz), which was compared to control without stimulation regarding to cell proliferation and cytokine production in vitro. For animal test, a micro-current stimulator chip was developed (120ldrs, 100 Hz 20ldrA/cm2). BDC was applied to the implant 7 days in beagle dog (n=10). No stimulation was applied to control group (n=10). The animals were sacrificed at 2 and 4 weeks after stimulation. Histological specimens was histomorphometrically analyzed. The number of osteoblasts was increased (31%, p<0.05) and VEGF was increased in the stimulated group (p<0.01). The bone volume (BV) and bone implant contact (BIC) in 2 weeks and BV in 4 weeks were significantly (p<0.05) increased in the test group compared to the control. BCS can contribute to enhanced osteogenesis, it could be applied clinically to the early bone formation around implants. View full abstract»

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  • Characterization of Mustn1PRO-GFPtpz transgenic mice

    Publication Year: 2007 , Page(s): 13 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1271 KB) |  | HTML iconHTML  

    Mustn1 has been characterized as a gene that has very restricted expression to the musculoskeletal system. However, its spatiotemporal expression was not comprehensively depicted in vivo. In this study, we have characterized the promoter of Mustn1 gene, which is mainly regulated by AP-1 family proteins. Subsequently, transgenic mice containing Mustn1 promoter-driven GFP transgene was generated. Mustn1 was found mainly expressed in the satellite cells in the adult mice, with notable expression coming from periosteum, endosteum and endothelium of blood vessels as well. This novel finding indicated that 1) Mustn1 is co-regulated with other common myogenic marker genes such as MyoD and mogenin; 2) Mustn1 is likely involved in the early differentiation of mesoderm due to the common origin of satellite cells and endothelial cells; and 3) Mustn1 is a differentiation marker that is specifically expressed in the musculoskeletal system. View full abstract»

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  • Longitudinal evaluation of the mechanical properties of biomineralized osteoblasts

    Publication Year: 2007 , Page(s): 15 - 16
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1028 KB) |  | HTML iconHTML  

    Understanding how biomineralization occurs in the extracellular matrix (ECM) of bone cells is crucial to the development of a successfully engineered bone tissue scaffold, and to date there has not been a well-established method for the quantitative examination of bone mineralization in situ. We investigated the mechanical properties of MC3T3-E1 osteoblast-like cells in vitro using shear modulation force microscopy (SMFM). The elastic modulus of the mineralizing cells increased at time points corresponding to mineral production, whereas that of the non-mineralizing cells did not vary significantly over time. View full abstract»

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  • Cortical bone morphology and mechanosensitivity are modulated by genetic variations

    Publication Year: 2007 , Page(s): 17 - 18
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    Genetic variations are a principal factor controlling bone morphology and mechanosensitivity. Genetically distinct inbred strains of mice provide an effective model to separate genetic from epigenetic factors. For example, BALE/cByJ mice not only have different morphology than C3H mice, but also lose most of their trabecular bone volume in the femur during disuse while C3H mice are comparatively unresponsive. Double-crossing these two strains, and thus generating a new population of mice with a wide range mechanosensitivity, allows the identification of the specific chromosomal regions that define the (distinct) response of the tissue to an environmental stimulus. Here, we report disuse-induced changes in femoral mid-diaphysial morphology of F2 mice population that were scanned by in-vivo muCT at baseline, upon 3wk disuse and 3wk of subsequent reambulation. Results indicate heterogeneous population was achieved for both baseline morphology and mechanosensitivity (longitudinal change during disuse and upon reambulation). Preliminary QTL maps indicate several chromosomal regions that may be responsible for the skeletal morphology. View full abstract»

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  • Muscle elastance and the force-velocity relation arise from a new model of muscle contraction

    Publication Year: 2007 , Page(s): 19 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1255 KB) |  | HTML iconHTML  

    Striated muscle may be functionally described using a new analytical model that treats muscle as a time, length, and velocity dependent force generator. A single analytical function is able to describe a wide range of contractile phenomena, including isometric contractions, isotonic contractions, and transient behavior, as well as demonstrating a direct force-length relation for passive and active muscle, a direct relation between initial muscle length and amount of shortening, and an inverse relation between muscle load and shortening. Hill's famous force-velocity relation, typically embodied as the "contractile element" of lumped muscle models, arises from this equation without separate assumptions. A new description of muscle elastance also emerges by taking the derivative of muscle force with respect to length. Muscle dynamics develop from a single equation based on the formation and relaxation of crossbridge bonds within the muscle. View full abstract»

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  • Analysis of the motion of rat head in impact acceleration injury tests

    Publication Year: 2007 , Page(s): 21 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    The kinematics of two head injury models with impact acceleration that produced severe and mild diffuse axonal injury in rats were investigated. The animals were instrumented with two triaxial accelerometers and the vertical motion was also recorded with high speed digital photography. The maximum linear and angular velocities in the severe injury model (7.2 m/s and 100 rad/s) were 4.0 and 3.3 times higher than the mild injury model showing that both linear and angular components of the motion may contribute to the severity of diffuse axonal injury. The results of this study can be used to develop an injury criterion for mild to severe diffuse axonal injury. View full abstract»

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  • Bone microstructure in OVX and normal rat bone as revealed by confocal and electron microscopy

    Publication Year: 2007 , Page(s): 23 - 24
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1141 KB) |  | HTML iconHTML  

    In our recent work we observed that the microstructure of the osteocyte lacunar-canalicular system is quite extensive, raising the possibility that the interstitial fluid porosity might have been previously underestimated. In this study we employed an ovariectomized (OVX) rat model to determine the effect of osteoporosis on interstitial fluid porosity. Bone sections were visualized using confocal and electron microscopy. Even though no statistical difference was found between the OVX and normal bone porosities, the total cortical porosity measured (~ 20%) was greater than values previously reported (~ 9%), the difference due to the complexity of the lacunar-canalicular network. Moreover, the analysis of tibial sections using electron microscopy revealed a pattern of higher mineralization in areas of low lacunar-canalicular porosity. More extensive studies involving the quantification of porosity in different cortical bone locations and especially of cancellous bone porosity are necessary to further investigate the effect of osteoporosis on bone's interstitial fluid pathway. View full abstract»

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  • Mechanical vibrations reduce the Intervertebral Disc swelling and muscle atrophy from Bed Rest

    Publication Year: 2007 , Page(s): 25 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB) |  | HTML iconHTML  

    Loss of functional weight bearing, such as experienced during space flight or bedrest, causes detrimental morphological volume changes to the intervertebral disc (IVD) beyond the normal diurnal cycle (10-13%), and muscle. Bed rest (BR) was used to test the hypothesis that, short-duration, low-magnitude, high-frequency mechanical vibrations will attenuate the IVD swelling and intrinsic back muscle atrophy induced by long-term bedrest. Control and experimental subjects underwent BR for up to 90d and were scanned by CT at Od and 90d, and by MRI at Od, 60d, 90d and 8d after completion of BR. In addition, experimental subjects received vibrations at 0.3g and 30Hz for lOmin/day. Muscle volume was measured by CT scans and IVD volume was measured by MRI scans. During BR, mechanical vibrations abated the IVD swelling at 60d by 150% and 90d by 65%. Eight days after bed rest, the control group showed a plasticity of 9%, while the experimental group showed no residual change (p>0.05). Mechanical vibrations reduced the intrinsic back muscle atrophy from long-term bed rest by 33% (p>0.05). These data demonstrate the rapid deterioration of the musculoskeletal system with BR but present vibrations as a promising non-pharmacologic countermeasure to disc degeneration and muscle atrophy. View full abstract»

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  • The effect of dynamic muscle stimulation on the musculo-skeletal remodeling

    Publication Year: 2007 , Page(s): 27 - 28
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    Elucidation of the interactive mechanism between musculoskeletal circulations and bone remodeling is crucial in developing new intervention to prevent bone loss under a microgravity environment. The overall hypothesis is that dynamic muscle stimulation can enhance fluid circulation in bone, regulate osteogenic adaptation, and inhibit bone loss in a functional disuse condition. Using a hindlimb suspension rat model, electro-induced dynamic muscle contraction was induced as replacement of the normal weight-bearing activity of the hindlimb. Dynamic muscle contraction loading at 20 Hz and 50 Hz demonstrated increase of BV/TV, Conn.D, and Tb.N at the metaphyseal regions, when comparing to the hindlimb suspension control. In addition, stimulation at 20 Hz and 50 Hz can also alleviate the reduction of the cross-sectional fiber area. These results demonstrated that dynamic electro-induced muscle contraction can indeed initiate an adaptive response to inhibit bone loss and reduce muscle atrophy under a functional disuse environment. View full abstract»

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  • The expression of lipid metabolism genes in bone are altered by mechanical stimuli

    Publication Year: 2007 , Page(s): 29 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1288 KB) |  | HTML iconHTML  

    Osteoblasts and adipocytes are two differentiated cell types which are both derived from mesenchymal stem cells (MSCs) and a reciprocal relationship may exist between osteoblastogenesis and adipogenesis in the bone marrow. Our previous studies in the mouse have indicated that low-magnitude, high-frequency mechanical stimuli can stimulate bone formation. To investigate whether lipid metabolism gene expression is altered during the application of low-level mechanical stimuli, adult female BALB/cByJ mice were subject to either disuse, mechanical vibration, or control conditions. RNA was extracted from the bones upon sacrifice after 4d. By microarray we screened lipid metabolism genes and confirmed them with real-time RT-PCR. Three genes were picked up - PPAR-gamma, Alox15 and Lrp5. PPAR-gamma and Alox15 were significantly down-regulated with mechanical vibrations, while Lrp5 was significantly down-regulated with disuse as indicated by the microarray data. It is speculated that mechanical stimuli down-regulate PPARgamma and Alox15, both of which are involved in promotion of osteoblastogenesis and inhibition of adipogenesis, result in bone formation and fat loss. However, disuse modulated gene expression changes in lipid metabolism were not necessarily opposite from those suffering from mechanical stimuli. View full abstract»

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  • Microprocessor based algorithms for controlling Electromyogram-driven devices

    Publication Year: 2007 , Page(s): 31 - 32
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1014 KB) |  | HTML iconHTML  

    The purpose of this study was to develop and evaluate signal-processing algorithms for controlling devices with electromyogram (EMG). An "EMG-driven car model" was developed whereby a remote control toy car was navigated by using two-channel EMG signals recorded from the right and left forearms with surface electrodes. After the EMG signals were amplified and filtered, they were digitized and processed with a PIC18F452 microprocessor. Two threshold detection algorithms with and with an infinite impulse response (IIR) filter were compared. The detected signals were used to navigate the car via a radio-frequency transmitter. This microprocessor-based system is useful for developing EMG-driven assistive technology devices. View full abstract»

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  • Nanometer resolution hard X-ray microscopy of bone and mineralized tissue

    Publication Year: 2007 , Page(s): 33 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1146 KB) |  | HTML iconHTML  

    Full field hard X-ray microscopy has recently been developed utilizing synchrotron light, enabling absorption and phase contrast imaging with a spatial resolution of 50 -100 nm. This technique has allowed us to image bone tissue at the nanoscale level, viewing the substructure of mineralized collagen fibers. Thin sections of tissue (5 and 50 mum thick) from the L3 vertebrae of Beagles and mineralizing MC3T3-E1 mouse osteoblasts were imaged at beamline 01B1 at the National Synchrotron Radiation Research Center (Hsinchu, Taiwan). Collagen fiber orientation was observed in the lamellar structure of an osteon. Mineralizing osteoblasts were found to produce disordered mineralized nodules with varying density and structure. View full abstract»

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