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Breast cancer remains the most frequently diagnosed cancer and is the leading cause of neoplastic disease burden for females worldwide, suggesting that effective therapeutic and/or diagnostic strategies are still urgently needed. In this study, a type of indocyanine green (ICG) and camptothecin (CPT) co-loaded perfluorocarbon double-layer nanocomposite named ICPNC was developed for detection and photochemotherapy of breast cancer. The ICPNCs were designed to be surface modifiable for on-demand cell targeting and can serve as contrast agents for fluorescence diffuse optical tomography (FDOT). Upon near infrared (NIR) irradiation, the ICPNCs can generate a significantly increased production of singlet oxygen compared to free ICG, and offer a comparable cytotoxicity with reduced chemo-drug dosage. Based on the results of animal study, we further demonstrated that the ICPNCs ([ICG]/[CPT] = 40-/7.5-μM) in association with 1-min NIR irradiation (808 nm, 6 W/cm2) can provide an exceptional anticancer effect to the MDA-MB-231 tumor-bearing mice whereby the tumor size was significantly reduced by 80% with neither organ damage nor systemic toxicity after a 21-day treatment. Given a number of aforementioned merits, we anticipate that the developed ICPNC is a versatile theranostic nanoagent which is highly promising to be used in the clinic.

This study presents a novel measurement scheme for near-infrared diffuse optical tomography through employing square-wave driving light sources to simultaneously obtain amplitude and phase delay data of multiple sinusoids for the reconstruction of optical-coefficient images.

Osseointegration is the key to the success of surgery of dental implantation. In this study, we proposed, implemented and explored a handheld and noncontact electromagnetic-type stability assessment device for the use after surgery. The device with two pairs of dual inductors incorporating with a driving signal of swept wavelets was first proposed. This detection device feeds 200–10 kHz of alternating current into an inductor to produce swept broadband magnetic flux and excite the implant structure with a magnetic pole. The implant vibration causes magnetic-flux changes and generates an induced electromotive force. The implant structure resonance frequency (RF) can be characterized to exhibit osseointegration status by evaluating the frequency response function. In vitro bone block experiment and in vivo animal testing were performed to validate the developed device. For bone block experiment on fourteen designs, besides two cancellous bones and two cortical-shell thicknesses, four interface tissues produced using varied mixing ratios of epoxy adhesive were to imitate osseointegration progress. Further, a pilot animal test was conducted on five female New Zealand rabbits to assess implant osseointegration in live bodies. Statistical analyses for varied bone models on measured RF, and the regression analysis between the measured RF and OsstellTM ISQ for in vivo testing were performed. The correlation analysis on the built regression models shows a close relationship between the measured RFs and ISQ quotients with the determination coefficients up to over 0.9.

On the basis of resonance frequency analysis, a noncontact handheld assessment device that employs the vibro-acoustic technique with acoustic excitation and displacement response sensing was developed to quantify the stability of dental implants. The assessment technique employed in the developed device is superior to the magnetic sensing technique that uses an accessory for assessment. The calculated response spectra that characterized dental-structure resonance indicated the trend of osseointegration. In vitro and in vivo tests were performed to verify the performance of the developed device. For in vitro bone block testing, in addition to two cancellous bones and two thicknesses of cortical shells, interface tissues produced using different mixing ratios of resin to hardener epoxy adhesive were used to mimic the osseointegration progress. Furthermore, preliminary animal testing was conducted on rabbits to observe implant osseointegration in live bodies. Statistical analyses for varied designed bone models on measured resonance frequency, and the regression analysis between VA and Osstell™ ISQ for in vivo testing were performed. The necessary statistical analyses on various issues were considered as well as their descriptions. The developed noncontact vibro-acoustic assessment device can be used to monitor the implant stability status without having to use a mounted accessory.

The use of inertial measurement units associated with various algorithms has been proposed and developed to evaluate functional abilities and kinematics for stroke patients. In previous research, complex mathematical models were adopted successfully to clarify and to validate the functional results from different sensors. However, only a few algorithms stemmed from the process of motor recovery after a stroke or the way to administer clinical assessment scales. Based on the recovery process or how to conduct the assessment scales, the algorithmsensor based module is supposed to accurately classify clinical motor recovery status and to provide additional kinematics in stroke survivors. In this study, only one sensor is affixed on the dorsum of the affected foot to reduce the burden on a weak extremity. A special movement while in seated, extend their knee and then dorsiflex their feet, based on the motor recovery process after stroke is proposed and tested to classify Brunnstrom stages for lower extremities. After analyzing 24 participants and adopting suitable threshold values for different Brunnstrom stages, the overall accuracy is 86.8%. The ability to distinguish Brunnstrom stage II from others can even reach a 100% accuracy. The accuracies for distinguishing Brunnstrom stage III, stage IV, and stage V are 86.6%, 94 %, and 92.8%, respectively. We also analyze these misclassified data and investigate why the errors occurred. The results reveal the feasibility of the kinematics-based algorithm even using a single sensor.

A working prototype of an optical breast imaging system involving a dual-direction parallel-plate scanning scheme in combination with a mammography machine was demonstrated and applied in imaging healthy and malignant breasts in a clinical environment.

This study is to develop an automatic classification system for lower limb Brunnstrom stage of hemiparetic patients. The measurement system is employed both IMU and sEMG to acquire the lower limb motion signals from patients. Afterward, this study extracted some useful features for the proposed rule-based classification system and compared different classification algorithms such as k-nearest neighbor, artificial neural network and support vector machine. Instead of leave one out cross validation, the leave subjects out cross validation was used to calculate the successful rate of classification. The results of the experiment on seventeen men and seven women at mean age: 60.6 ± 12.4 years after stroke for more than 6 months show that SVM (95.2%) has the highest accuracy to classify Brunnstrom stage than k-NN (89.2%) and ANN (92.3%). The robustness of this classification system was verified by training different number of subject data. According to the classification result, it can be concluded that the proposed classification system has the potential to predict the lower limb Brunnstrom stage for hemiparetic patients.

Diffuse optical imaging (DOI) is emerging as a new functional imaging modality that can be used for breast cancer screening. Due to the ill-posed inverse problem for DOI image reconstruction, regularization is essential to remedy such a drawback. In our previous study, we have successfully implemented edge-preserving regularization into image reconstruction algorithm for improving the reconstructed images. In this study, we incorporate additional anatomical image, which can be obtained from other imaging modality such as mammography or magnetic resonance imaging, although showing no tumor information, into edge-preserving regularization for further improving the reconstructed images. Reconstruction results show that the quality of reconstructed images can be significantly improved.

The elimination of whip using electromagnetic exciters (EEs) is investigated in this paper. First, mathematical models of a rotor-bearing system are derived. The threshold of instability determining if the rotor-bearing system experiences fluid-induced instability is obtained. Then, an experimental rotor-bearing system is designed and constructed to justify the elimination of whip, and orbit, spectrum, and spectrum cascade plots are obtained from the experimental data. The proposed procedure applies root locus plots to simulate the threshold of instability, and the spring model is used to compute the stiffness that the system needs to address the whip problem. Moreover, design examples are illustrated to explain the calculation process that tackles the proportional (simulating stiffness) and derivative (simulating damping) parameters of the EE to improve the stiffnesses of the rotor-bearing system. The main contribution of the present experimental work is that by using the EE it is possible to increase the stiffness of the rotor-bearing system and lead to the rotor-bearing system with a higher threshold of stability and eliminate the whip instability.

Self-excited reverse precessional full annular rub, known as “dry whip”, is a secondary phenomenon resulting from a primary cause and may lead to a machine catastrophic failure; i.e., “coexistence of oil and dry whips” which occurs repeatedly with constant frequency and amplitude in small clearance cases. This paper presents a technique using an electromagnetic actuator, which can raise the threshold of instability of fluid-film bearings and then eliminate both oil and dry whips in the normal, operational range. The study constructs a set of experimental setup, sets up a general model of a rotor-bearing-seal system with an electromagnetic actuator to derive the corresponding governing motion equations, evaluates the supplemental stiffness supplied by the electromagnetic actuator, judges instabilities by root locus plots, and finally establishes a set of criterion for eliminating coexistence of oil and dry whips. Experimental results demonstrate that the coexistence of the oil and dry whips of the rotating machine can be removed effectively. The proposed technique can be used to diagnose rub and fluid-induced instability in this kind of rotating machine.

This paper describes an experimental investigation of whirl elimination of a hydrodynamic bearing with an electromagnetic exciter (EE) and includes a stability analysis through a root locus plot. The test apparatus incorporates the EE, which provides additional stiffness through a PD algorithm in order to stiffen a rotating machine to resolve fluid-induced instability. The stiffness of the hydrodynamic bearing gives a significant contribution to the occurrence of unstable vibrations as the speed or the load of a rotating machine increases. With regard to the whirl-eliminated investigations, the EE used to raise the stiffness of the rotating machine can cause important changes in the stability of the rotating machine. The threshold of stability derived in this paper that affects stability conditions can be used to define the stability margin of the rotating machine. A simple control scheme is used to calculate the amount of the supplemental stiffness supplied by the EE, and is confirmed through experiments. To offer a faster, more stable and more effective strategy for whirl elimination, the dynamic behavior of a rotor system affected by fluid-induced whirl instability phenomena has been successfully studied.

In this paper, the slight variation in low‐contrast optical properties of an inclusion (tumor) is estimated and investigated by near infra‐red diffusive optical tomography (NIR DOT). We show that absorption‐image reconstruction of test phantoms is based on the continuous wave domain with the aid of structural a priori knowledge obtained from other imaging modalities as well as empirical updating information that is proportional to the off‐boundary distance, but not the size of inclusion against the background. Numerical simulation is demonstrated using various sizes, locations and contrasts of inclusion, where a stable and accurate reconstruction of absorption‐coefficient images can be achieved using our method with structural knowledge and updating information.

In clinical settings, traditional stroke rehabilitation evaluation methods are subjectively scored by occupational therapists, and the assessment results vary individually. To address this issue, this study aims to develop a stroke rehabilitation assessment system by using inertial measurement units. The inertial signals from the upper extremities were acquired, from which three quantitative indicators were extracted to reflect rehabilitation performance during stroke patients’ movement examination, i.e., shoulder flexion. Both healthy adults and stroke patients were recruited to correlate the proposed quantitative evaluation indices and traditional rehab assessment scales. Especially, as a unique feature of the study the weight for each of three evaluation indicators was estimated by the least squares method. The quantitative results demonstrate the proposed method accurately reflects patients’ recovery from pre-rehabilitation, and confirm the feasibility of applying inertial signals to evaluate rehab performance through feature extraction. The implemented assessment scheme appears to have the potential to overcome some shortcomings of traditional assessment methods and indicates rehab performance correctly.

In this presentation, we demonstrate a working prototype of an optical breast imaging system using parallel-paddle architecture with dual-direction scanning, of which the designed module can be incorporated with a mammographic system for the acquisition of optical transmission and reflection information in both directions of up-down and down-up. Additionally, the scanning module enables to move with a designated pitch to accommodate varied breast size for acquiring adequate data to reconstruct the images. Currently, continuous-wave near infrared illumination modules are used for experimentation. The feasibility will be presented by phantom test.

As optimized wavelengths are used, a nearinfrared (NIR) tomographic imaging system using multiwavelengths in continuous wave has the potential to provide accurate information of chromophores. In this paper, we discuss wavelength optimization with commercial laser diodes. Through theoretical analysis, we use the residual norm (R) and the condition number (κ) representing the uniqueness of this matrix problem (Eq. (6)) and the smooth singular-value distribution of each chromophore, respectively. The optimum wavelengths take place as large R and small κ We found 37 wavelengths in total from the 633nm-980nm range available in the market to discover optimum wavelength sets for a broad range of chromophore combinations. From a complete set of 37 wavelengths, there exist 7770 (C37 3), 66045 (C37 4), and 435897 (C37 5) combinations of three, four, and five wavelength sets, respectively, for accurately estimating chromophores (HbO2 and HbR) plus the scattering prefactor A. With the numerical calculation, top 10 wavelength sets were selected based on high R and low k. Furthermore, it is found that 650, 730, 905, 705, and 690 nm are optimal with a same part for three, four, and five wavelength sets, respectively.

For employing optimized wavelengths, a near-infrared (NIR) tomographic imaging system with multiwavelengths in a continuous wave (CW) enables us to provide accurate information of chromophores. In this paper, we discuss wavelength optimization with a selection from commercial laser diodes. Through theoretical analysis, the residual norm (R) and the condition number (κ) represent the uniqueness of a matrix problem and the smooth singular-value distribution of each chromophore, respectively. The optimum wavelengths take place for large R and small κ. We considered a total of 38 wavelengths of laser diodes in the range of 633–980 nm commercially available to discover optimum sets for a broad range of chromophore combinations. In the 38 wavelengths, there exists 501,942 (C538), 2,760,681 (C638), and 12,620,256 (C738) combinations of five, six, and seven wavelength sets, respectively, for accurately estimating chromophores (HbO2, HbR, H2O, and lipids), water, lipids, and the scattering prefactor A. With the numerical calculation, the top 10 wavelength sets were selected based on the principle of large R and small κ. In the study, the chromophore concentration for young and elderly women are investigated; finally, choosing the laser diodes with a wavelength of 650, 690, 705, 730, 870/880, 915, and 937 nm is recommended either for young or elderly women to construct a spectral NIR tomographic imaging system in the CW domain. Simulated data were used to validate the claims.

This study employed a noncontact resonance frequency (RF) detection technique that was developed by our group to evaluate the interfacial bone in in vitro implant-bone models. Based on our method, the implant-bone structure was excited by the acoustic energy of a loudspeaker, and its vibration response was acquired with a capacitance sensor. The spectral analysis was used to characterize the first RF value. Two types of in vitro defect models, Buccal-Lingual (BL) and Mesial-Distal (MD), were constructed for the verification. The measurements of the RF for a defect model clamped at four different heights (9, 10, 11, and 12 mm) were performed in two sensing directions (BL and MD). Moreover, each model was also analyzed using an Osstell Mentor. The obtained two parameters, RF and ISQ (Implant Stability Quotient), were statistically analyzed through one-way analysis of variance (ANOVA) and linear regression analysis for comparisons. The RF and the ISQ values obtained for all of the defect models at the four clamp heights decreased significantly (p < 0.05) with an increase in the severity of the defect. The two parameters for each imperfection increase significantly (p < 0.05) with an increase in the clamp height. Additionally, the RFs of all of the defect models are linearly correlated with their corresponding ISQs for the four clamp heights and the two measuring orientations. Therefore, our developed technique is feasible for the assessment of the postoperative healing around a dental implant.

The study aims at developing an optical measurement module incorporated with an X-ray mammographic system to obtain diffuse optical images (DOI) for the detection of breast tumors. Two goals steer the study: (1) to enhance sensitivity and specificity of tumor detection through the use of functional DOI; and (2) to reduce radiation exposure by using only one mammogram, instead of two, as structure information to compute optical-coefficient images. A dual-direction (downward and upward) scanning device to project illuminated near infrared light with multiple-channel switching for both sources and detectors was designed and constructed to obtain double information. The designed and constructed NIR scanning module incorporates with GE Senographe 2000D to assist breast tumor detection.

System verification and the reconstructed optical-property images of breast-like phantoms and biological tissue are presented using a ring-scanning-based imaging system of frequency-domain near infrared diffuse optical tomography with a high degree of spatial flexibility.

X-ray mammography has been used in the early detection of breast tumors for decades. Related techniques to enhance preventive screenings are still demanding. Since the 1990s, near infrared diffuse optical tomography (NIR DOT), a functional medical imaging modality, is being exploited and developed to reconstruct optical-coefficient images of tissues. Much endeavor to improve the spatial resolution and contrast of DOT images has been exerted for clinic applications in the diagnosis of breast tumors. The study aims at the design, implementation, and verification of a mammography based NIR DOT. This multimodality imaging method is able to provide information that neither X-ray nor diffuse optical tomography can give alone. To this end, a device with multiple-channel switching of NIR sources and translational scanning of out-emitted intensity constructed on a commercialized mammography system is being designed and built up. We employ the mammography image as structure information that is used as an initial guess for the image reconstruction of optical properties of tissues. Preliminary numerical trials are performed using heterogeneous phantoms made of high-scattering Intralipid. Promising results are obtained with various spatial resolutions due to partial NIR detected intensity.

Dental implants are generally used in edentulous patients. The key issue of this dental surgery is the effective osseointegration of implants with spongy bone and cortical bone and then they become a part of loading structure. Current osseointegration detection devices only offer overall evaluation without the information of location and orientation of bone defects. This study is to develop detection techniques to measure the quantity as well as to locate the orientation of imperfection around bone-implant interface based on resonance frequency analysis (RFA). A noncontact measurement technique is performed with acoustic excitation through a loud-speaker and displacement response via a capacity-type pick-up. In the first and second series experiments, RFA is applied to estimate the orientation and quantity of irregular bone defects on various in-vitro faulty models. The variation in RF not only locates the orientation and depth of defects but also reflects the change of boundary conditions surrounding the defective models. According to these results, the detection technique to locate irregular osseointegration is established. Furthermore, the detection device to this end is proposed as well. The proposed examining approach and device are promising and able to assist dentists in dental implant surgery.

A promising method to achieve rapid convergence for image reconstruction is introduced for the continuous-wave near-infrared (NIR) diffuse optical tomography (DOT). Tomographic techniques are usually implemented off line and are time consuming to realize image reconstruction, especially for NIR DOT. Therefore, it is essential to both speed up reconstruction and achieve stable and convergent solutions. We propose an approach using a constraint based on a Lorentzian distributed function incorporated into Tikhonov regularization, thereby rapidly converging a stable solution. It is found in the study that using the proposed method with around five or six iterations leads to a stable solution. The result is compared to the primary method usually converging in approximately 25 iterations. Our algorithm rapidly converges to stable solution in the case of noisy (>20 dB) detected intensities.

Journal bearings are commonly used in large rotary machineries because they have excellent mechanical and geometric properties as well as large load-carrying capacities. Nevertheless, the oil whirl and oil whip instabilities limit their applications due to their insufficient stiffness at high running speeds. This paper presents a method to increase the stiffness of a rotating machine using an electromagnetic exciter (EE), which can raise the threshold of instability of the rotating machine and eliminate fluid-induced instability. The EE is a controllable auxiliary device that can provide additional stiffness to the bearings to increase the operating ranges of a rotating machine, while the journal bearings act as load-carrying devices. Together, the EE complements the JB to stiffen the rotor system and raise the threshold of instability. A simple control scheme is used to calculate the amount of supplemental stiffness supplied by the EE. The experimental results demonstrate that the oil whirl and oil whip instabilities of the rotating machine can be eliminated effectively, even at higher running speeds. The advantage of the EE is to offer a faster, more stable method to eliminate fluid-induced instability.Copyright © 2009 by ASME

The paper studies the tomography reconstruction of the intra-lipid phantom measured with near infra-red (NIR) light (800nm) using a tomographic scanning device in the DC domain, where the homogenous intra-lipid phantom as the normal tissue is inserted with another different volume density one as a tumor. In our research, the instrument of continuous wave as implied by the name employs continuous-wave light as a light source where the measurement of emerging light can yield the wavelength dependent attenuation. With comparing the difference between the homogeneous and the heterogeneous phantoms, 1-D signal measurement indicates the angular position of the inclusion. Following the measuring procedure, the numerical simulation to reconstruct tomographic images of optical properties was performed using 16 by 16 sources/detectors combination and the initial guess with a homogenous background for all cases where the finite element (FE) analysis was implemented. With the use of real measured data, promising results of tomographic absorption and diffusive image are successfully reconstructed.

The study aims at developing a near infrared (NIR) tomography imaging system using a single rotating source/detector scanning device, which will be working for diffuse optical tomography (DOT) on medical applications. Some influential factors in terms of the design of this scanning device and test phantoms are investigated such as the temporal stability, air-absorption, container influence, and radiance normalization, etc. Then, a heterogeneous microsphere phantom with an off-center inclusion is investigated. It is observed that the radiance deviation between the heterogeneous and the homogenous is shifting with the inclusion position accordingly. Through the previously-mentioned system calibration, the back projection method as widely applied in the computed tomography (CT) technique is used to reconstruct optical images which indicate the distribution of optical property of the test phantom.

This study develops a non-contact vibro-acoustic detection technique for measuring the defect quantity and determining the imperfection orientation surrounding a bone-implant interface. Acoustic excitation through a miniature loud speaker and vibration response measurement using a capacity-type displacement sensor are applied to accomplish this task to prevent the mass loading effect on the structure to be examined. The proposed non-contact excitation-response measurements are verified using a series of designated in vitro defect models, and the measured resonance frequencies (RFs) are used to discriminate interfacial structure variations. A finite element modal analysis is conducted to validate the measured RFs. Additionally, a prototype device is developed and applied to assess the osseointegration between dental implants and tibia in an in vivo animal model. A comparison of in vitro experimental results with numerical simulations shows that the RFs in the defective orientation are significantly smaller than those in the complete direction (p ＜ 0.05), and that the values decrease with increasing defect quantity (p ＜ 0.05). Moreover, the defect depth affects RF variation. In the in vivo experiments, the RF levels in the lateral direction of the tibia are much higher than those in the axial direction (p ＜ 0.05) of the tibia. The RF values in the axial direction for two implants have no significant difference (p = 0.552), but the RFs in the lateral direction for implant 2 are higher than those for implant 1 (p ＜ 0.05). The RF changes can be compared to assess osseointegration development. The proposed technique is promising for assisting dentists in the assessment of implant stability after surgery.