Behavioral Caenorhabditis elegans mutants are sought for the purposes of neurobiological research... more Behavioral Caenorhabditis elegans mutants are sought for the purposes of neurobiological research. Until now, large numbers of worms with neuronal defects have been obtained through mutagenesis techniques. However, the existing screening procedures are not only time-consuming and low-throughput, but also tedious and labor-intensive. Therefore, developing a rapid and convenient method to overcome these difficulties is necessary. The present study demonstrates for the first time a microdevice for the rapid screening of chemotaxis-defective mutants based on their chemotactic response. The microchip is capable of automatic introduction, local immobilization, and controllable generation of concentration gradients during the screening assays. With this device, six C. elegans behavioral assays can be performed using various attractants without requiring anesthetics for local capture, and ten mutants are effectively isolated from 10(4) mutagenized worms in 100 min. The microfluidics-based method is robust enough to sort the chemotaxis-defective worms with 91 % accuracy from a large population of wild type animals during a mutagenesis screen.
ABSTRACT In this paper, the current standard method and other commonly used engineering practices... more ABSTRACT In this paper, the current standard method and other commonly used engineering practices for linear or linearized engineering failure data analysis are critically reviewed first, and the existing issues are also indicated. To overcome these issues, a linear data analysis method based on a new equilibrium mechanism is subsequently presented. Based on the equilibrium mechanism, three possible ideal data patterns are identified and the corresponding best curve fitting approaches are proposed. Compared to the existing methods, the equilibrium method not only provides quantitative solutions of fit parameters, but also gives an obvious physical meaning and, therefore, is more intuitive in quickly and correctly identifying data patterns, subsequent data preprocessing, and evaluating goodness-of-fit. The equilibrium method is further applied to fatigue and creep data analyses to demonstrate its applicability.
Freehand three-dimensional ultrasound imaging is a highly attractive research area because it is ... more Freehand three-dimensional ultrasound imaging is a highly attractive research area because it is capable of volumetric visualization and analysis of tissues and organs. The reconstruction algorithm plays a key role to the construction of three-dimensional ultrasound volume data with higher image quality and faster reconstruction speed. However, a systematic approach to such problem is still missing. A new fast marching method (FMM) for three-dimensional ultrasound volume reconstruction using the tracked and hand-held probe is proposed in this paper. Our reconstruction approach consists of two stages: bin-filling stage and hole-filling stage. Each pixel in the B-scan images is traversed and its intensity value is assigned to its nearest voxel in the bin-filling stage. For the efficient and accurate reconstruction, we present a new hole-filling algorithm based on the fast marching method. Our algorithm advances the interpolation boundary along its normal direction and fills the area closest to known voxel points in first, which ensure that the structural details of image can be preserved. Experimental results on both ultrasonic abdominal phantom and in vivo urinary bladder of human subject and comparisons with some popular algorithms are used to demonstrate its improvement in both reconstruction accuracy and efficiency.
A novel sandwich-type electrochemical immunosensor based on functionalized nanomaterial labels an... more A novel sandwich-type electrochemical immunosensor based on functionalized nanomaterial labels and bienzyme (horseradish peroxidase and glucose oxidase) biocatalyzed precipitation was developed for the detection of α-fetoprotein (AFP). The enzymes linked to functionalized nanomaterials as biocatalysts could accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to yield the insoluble product on the electrode surface; the mass loading of the precipitates on the device led to a significant enhanced signal. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to monitor the enhanced precipitation of 4-CN that accumulated on the electrode surface and subsequent decrement in the electrode surface area by monitoring the reduction process of the Fe(CN)6(4-/3-) redox couple. Under optimal conditions, the proposed immunosensor showed a high sensitivity and a wide linear range from 0.001 to 60 ng mL(-1) with a low detection limit of 0.33 pg mL(-1). Moreover, the immunosensor exhibited good selectivity, acceptable stability and reproducibility. The amplification strategy showed good promise for clinical screening of tumor biomarkers.
In this paper, a constitutive model for characterization of mechanical response in inelastic comp... more In this paper, a constitutive model for characterization of mechanical response in inelastic composite materials due to damage developed recently by the authors is first outlined. The formulation is based on the concept of damage surface and on the assumption that the change of material behavior is independent of loading path over which the damage state of material develops, but is dependent on the current stress state and the energy dissipated. The method is applied to describe the behaviors of graphite fiber reinforced composite laminates containing a small hole. The elastic-damaged response of interlaminar stresses in the composite laminates due to uniaxial tension is investigated with the aid of displacement-based finite element method. The initiation and development of damage zones in the laminates are examined using a three-dimensional analysis. The results of interlaminar stress distributions of the composite laminates analyzed with and without taking material stiffness degradation into account under the same external loading condition are presented and discussed.
ABSTRACT A new approach has been developed by the authors to estimate the load share of worm gear... more ABSTRACT A new approach has been developed by the authors to estimate the load share of worm gear drives, and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors. In the approach, the finite element (FE) modelling is based on the modified tooth geometry, which ensures that the worm gear teeth are in localized contact. The geometric modelling method for involute worm gears allows the tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of finite element analysis, the instantaneous meshing stiffness and loaded transmission errors are obtained and the load share is predicted. In comparison with existing methods, this approach applies loaded tooth contact analysis and provides more accurate load capacity rating of worm gear drives.
Hearing loss as a common comorbidity in children with cleft lip and/or palate has been well docum... more Hearing loss as a common comorbidity in children with cleft lip and/or palate has been well documented. Auditory impairment may contribute to abnormalities in speech, language and learning abilities, and other communicative disorders in children with oral clefts. The functional consequences of hearing loss in this group should not be underestimated. In this paper, the existing literature is reviewed with an emphasis on the prevalence, type, assessment, and management methods for hearing loss in children with cleft lip and/or palate. The prevalence of hearing disorders reported in western patients with cleft lip and/or palate is generally higher than in the eastern countries. However, hearing loss is common in children with cleft lip and/or palate of all ethnicities. Conductive hearing loss caused by middle ear disease is reported to occur frequently in syndromic and non-syndromic cleft cases. The prevalence of sensorineural hearing loss is relatively higher in syndromic clefts than nonsyndromic clefts. Assessments of hearing loss in children with clefts should include case history taking and a detailed audiometric evaluation, and should be performed by otolaryngology and audiology professionals. Surgical treatment, including closure of clefts and ventilation tube insertion, is reported to be effective in reducing conductive hearing loss but this remains controversial. Nonsurgical treatments for middle ear disease and hearing aids have also been suggested in recent studies. This review also highlights the possible role of central auditory processing disorder in the hearing loss of children with cleft lip and/or palate, and recommends the systematic study of central auditory processing in children with cleft lip and/or palate.
Behavioral Caenorhabditis elegans mutants are sought for the purposes of neurobiological research... more Behavioral Caenorhabditis elegans mutants are sought for the purposes of neurobiological research. Until now, large numbers of worms with neuronal defects have been obtained through mutagenesis techniques. However, the existing screening procedures are not only time-consuming and low-throughput, but also tedious and labor-intensive. Therefore, developing a rapid and convenient method to overcome these difficulties is necessary. The present study demonstrates for the first time a microdevice for the rapid screening of chemotaxis-defective mutants based on their chemotactic response. The microchip is capable of automatic introduction, local immobilization, and controllable generation of concentration gradients during the screening assays. With this device, six C. elegans behavioral assays can be performed using various attractants without requiring anesthetics for local capture, and ten mutants are effectively isolated from 10(4) mutagenized worms in 100 min. The microfluidics-based method is robust enough to sort the chemotaxis-defective worms with 91 % accuracy from a large population of wild type animals during a mutagenesis screen.
ABSTRACT In this paper, the current standard method and other commonly used engineering practices... more ABSTRACT In this paper, the current standard method and other commonly used engineering practices for linear or linearized engineering failure data analysis are critically reviewed first, and the existing issues are also indicated. To overcome these issues, a linear data analysis method based on a new equilibrium mechanism is subsequently presented. Based on the equilibrium mechanism, three possible ideal data patterns are identified and the corresponding best curve fitting approaches are proposed. Compared to the existing methods, the equilibrium method not only provides quantitative solutions of fit parameters, but also gives an obvious physical meaning and, therefore, is more intuitive in quickly and correctly identifying data patterns, subsequent data preprocessing, and evaluating goodness-of-fit. The equilibrium method is further applied to fatigue and creep data analyses to demonstrate its applicability.
Freehand three-dimensional ultrasound imaging is a highly attractive research area because it is ... more Freehand three-dimensional ultrasound imaging is a highly attractive research area because it is capable of volumetric visualization and analysis of tissues and organs. The reconstruction algorithm plays a key role to the construction of three-dimensional ultrasound volume data with higher image quality and faster reconstruction speed. However, a systematic approach to such problem is still missing. A new fast marching method (FMM) for three-dimensional ultrasound volume reconstruction using the tracked and hand-held probe is proposed in this paper. Our reconstruction approach consists of two stages: bin-filling stage and hole-filling stage. Each pixel in the B-scan images is traversed and its intensity value is assigned to its nearest voxel in the bin-filling stage. For the efficient and accurate reconstruction, we present a new hole-filling algorithm based on the fast marching method. Our algorithm advances the interpolation boundary along its normal direction and fills the area closest to known voxel points in first, which ensure that the structural details of image can be preserved. Experimental results on both ultrasonic abdominal phantom and in vivo urinary bladder of human subject and comparisons with some popular algorithms are used to demonstrate its improvement in both reconstruction accuracy and efficiency.
A novel sandwich-type electrochemical immunosensor based on functionalized nanomaterial labels an... more A novel sandwich-type electrochemical immunosensor based on functionalized nanomaterial labels and bienzyme (horseradish peroxidase and glucose oxidase) biocatalyzed precipitation was developed for the detection of α-fetoprotein (AFP). The enzymes linked to functionalized nanomaterials as biocatalysts could accelerate the oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to yield the insoluble product on the electrode surface; the mass loading of the precipitates on the device led to a significant enhanced signal. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to monitor the enhanced precipitation of 4-CN that accumulated on the electrode surface and subsequent decrement in the electrode surface area by monitoring the reduction process of the Fe(CN)6(4-/3-) redox couple. Under optimal conditions, the proposed immunosensor showed a high sensitivity and a wide linear range from 0.001 to 60 ng mL(-1) with a low detection limit of 0.33 pg mL(-1). Moreover, the immunosensor exhibited good selectivity, acceptable stability and reproducibility. The amplification strategy showed good promise for clinical screening of tumor biomarkers.
In this paper, a constitutive model for characterization of mechanical response in inelastic comp... more In this paper, a constitutive model for characterization of mechanical response in inelastic composite materials due to damage developed recently by the authors is first outlined. The formulation is based on the concept of damage surface and on the assumption that the change of material behavior is independent of loading path over which the damage state of material develops, but is dependent on the current stress state and the energy dissipated. The method is applied to describe the behaviors of graphite fiber reinforced composite laminates containing a small hole. The elastic-damaged response of interlaminar stresses in the composite laminates due to uniaxial tension is investigated with the aid of displacement-based finite element method. The initiation and development of damage zones in the laminates are examined using a three-dimensional analysis. The results of interlaminar stress distributions of the composite laminates analyzed with and without taking material stiffness degradation into account under the same external loading condition are presented and discussed.
ABSTRACT A new approach has been developed by the authors to estimate the load share of worm gear... more ABSTRACT A new approach has been developed by the authors to estimate the load share of worm gear drives, and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors. In the approach, the finite element (FE) modelling is based on the modified tooth geometry, which ensures that the worm gear teeth are in localized contact. The geometric modelling method for involute worm gears allows the tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of finite element analysis, the instantaneous meshing stiffness and loaded transmission errors are obtained and the load share is predicted. In comparison with existing methods, this approach applies loaded tooth contact analysis and provides more accurate load capacity rating of worm gear drives.
Hearing loss as a common comorbidity in children with cleft lip and/or palate has been well docum... more Hearing loss as a common comorbidity in children with cleft lip and/or palate has been well documented. Auditory impairment may contribute to abnormalities in speech, language and learning abilities, and other communicative disorders in children with oral clefts. The functional consequences of hearing loss in this group should not be underestimated. In this paper, the existing literature is reviewed with an emphasis on the prevalence, type, assessment, and management methods for hearing loss in children with cleft lip and/or palate. The prevalence of hearing disorders reported in western patients with cleft lip and/or palate is generally higher than in the eastern countries. However, hearing loss is common in children with cleft lip and/or palate of all ethnicities. Conductive hearing loss caused by middle ear disease is reported to occur frequently in syndromic and non-syndromic cleft cases. The prevalence of sensorineural hearing loss is relatively higher in syndromic clefts than nonsyndromic clefts. Assessments of hearing loss in children with clefts should include case history taking and a detailed audiometric evaluation, and should be performed by otolaryngology and audiology professionals. Surgical treatment, including closure of clefts and ventilation tube insertion, is reported to be effective in reducing conductive hearing loss but this remains controversial. Nonsurgical treatments for middle ear disease and hearing aids have also been suggested in recent studies. This review also highlights the possible role of central auditory processing disorder in the hearing loss of children with cleft lip and/or palate, and recommends the systematic study of central auditory processing in children with cleft lip and/or palate.
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