We presents a Born; iterative method, for reconstructing optical properties of turbid media by means of frequency-domain data. The approach is based on iterative solution of a linear perturbation equation, which is derived from the integral from of the Helmholtz wave equation for photon-density waves in each iteration the total field and the associated weight matrix are recalculated based on the previous reconstructed image. We then obtain a new estimate by solving the updated perturbation equation. The forward solution, also based on a Helmholtz equation, is obtained by a multigrid finite difference method. The inversion is carried out through a Tikhonov regularized optimization process by the conjugate gradient descent method. Using this method, we first reconstruct the distribution of the complex wave numbers in a test medium, from which the absorption and the scattering distributions are then derived. Simulation results with two-dimensional test media have shown that this method can yield quantitatively (in terms of coefficient valued) as well as qualitatively (in terms of object location and shape) accurate reconstructions of absorption and scattering distributions in cases in which the first-order Born approximation cannot work well. Both full-angle and limited-angle measurement schemes have been simulated to examine the effect of the location of detectors and sources. The robustness of the algorithm to noise has also been evaluated.

Abstract-In this paper, we present a wavelet-based multigrid approach to solve the perturbation equation encountered in optical tomography. With this scheme, the unknown image, the data, as well as the weight matrix are all represented by wavelet expansions, thus yielding a multiresolution representation of the original perturbation equation in the wavelet domain. This transformed equation is then solved using a multigrid scheme, by which an increasing portion of wavelet coefficients of the unknown image are solved in successive approximations. One can also quickly identify regions of interest (ROI's) from a coarse level reconstruction and restrict the reconstruction in the following fine resolutions to those regions. At each resolution level a regularized least squares solution is obtained using the conjugate gradient descent method. This approach has been applied to continuous wave data calculated based on the diffusion approximation of several two-dimensional (2-D) test media. Compared to a previously reported one grid algorithm, the multigrid method requires substantially shorter computation time under the same reconstruction quality criterion.

TEAS using a frequency of 2/100Hz could help to improve the IVF outcomes partly by increasing NPY levels in the follicular fluids.

We present an iterative total least-squares algorithm for computing images of the interior structure of highly scattering media by using the conjugate gradient method. For imaging the dense scattering media in optical tomography, a perturbation approach has been described previously [Y. Wang et al., Proc. SPIE 1641, 58 (1992); R. L. Barbour et al., in Medical Optical Tomography: Functional Imaging and Monitoring (Society of Photo-Optical Instrumentation Engineers, Bellingham, Wash., 1993), pp. 87-120], which solves a perturbation equation of the form W delta x = delta I. In order to solve this equation, least-squares or regularized least-squares solvers have been used in the past to determine best fits to the measurement data delta I while assuming that the operator matrix W is accurate. In practice, errors also occur in the operator matrix. Here we propose an iterative total least-squares (ITLS) method that minimizes the errors in both weights and detector readings. Theoretically, the total least-squares (TLS) solution is given by the singular vector of the matrix [W/ delta I] associated with the smallest singular value. The proposed ITLS method obtains this solution by using a conjugate gradient method that is particularly suitable for very large matrices. Simulation results have shown that the TLS method can yield a significantly more accurate result than the least-squares method.

Background/Aims: Water channels, also named aquaporins (AQPs), play crucial roles in cellular water homeostasis. Methods: RT-PCR indicated the mRNA expression of AQPs 1-5, 7, 9, and 11-12, but not AQPs 0, 6, 8, and 10 in the 2∼8-cell stage human embryos. AQP3 and AQP7 were further analyzed for their mRNA expression and protein expression in the oocyte, zygote, 2-cell embryo, 4-cell embryo, 8-cell embryo, morula, and blastocyst from both human and mouse using RT-PCR and immunofluorescence, respectively. Results: AQP3 and AQP7 were detected in all these stages. Knockdown of either AQP3 or AQP7 by targeted siRNA injection into 2-cell mouse embryos significantly inhibited preimplantation embryo development. However, knockdown of AQP3 in JAr spheroid did not affect its attachment to Ishikawa cells. Conclusion: These data demonstrate that multiple aquaporins are expressed in the early stage human embryos and that AQP3 and AQP7 may play a role in preimplantation mouse embryo development.

Contact lenses have become a popular health‐monitoring wearable device due to their direct contact with the eyes. By integrating biosensors into contact lenses, real‐time and noninvasive diagnoses of various diseases can be realized. However, current contact lens sensors often require complex electronics, which may obstruct the user's vision or even damage the cornea. Moreover, most of the reported contact lens sensors can only detect one analyte. Therefore, an optical‐based dual‐functional smart contact lens sensor has been introduced to monitor intraocular pressure (IOP) and detect matrix metalloproteinase‐9 (MMP‐9), both of which are key biomarkers in many eye‐related diseases such as glaucoma. Specifically, the elevated IOP is continuously monitored by applying an antiopal structure through color changes, without any complex electronics. Together with the peptide modified gold nanobowls (AuNBs) surface‐enhanced Raman scattering (SERS) substrate, the quantitative analysis of MMP‐9 at a low nanomolar range is achieved in real tear samples. The dual‐sensing functions are thus demonstrated, providing a convenient, noninvasive, and potentially multifunctional sensing platform for monitoring health and diagnostic biomarkers in human tears.

Ye Y, Griffin MJ. Reductions in finger blood flow in men and women induced by 125-Hz vibration: association with vibration perception thresholds. J Appl Physiol 111: 1606 -1613, 2011. First published September 15, 2011 doi:10.1152/japplphysiol.00407.2011.-Vibration of one hand reduces blood flow in the exposed hand and in the contralateral hand not exposed to vibration, but the mechanisms involved are not understood. This study investigated whether vibration-induced reductions in finger blood flow are associated with vibrotactile perception thresholds mediated by the Pacinian channel and considered sex differences in both vibration thresholds and vibration-induced changes in digital circulation. With force and vibration applied to the thenar eminence of the right hand, finger blood flow and finger skin temperature were measured in the middle fingers of both hands at 30-s intervals during seven successive 4-min periods: 1) pre-exposure with no force or vibration, 2) pre-exposure with force, 3) vibration 1, 4) rest with force, 5) vibration 2, 6) postexposure with force, and 7) recovery with no force or vibration. A 2-N force was applied during periods 2-6 and 125-Hz vibration at 0.5 and 1.5 ms Ϫ2 root mean square (r.m.s.; unweighted) was applied during periods 3 and 5, respectively. Vibrotactile thresholds were measured at the thenar eminence of right hand using the same force, contact conditions, and vibration frequency. When the vibration magnitude was greater than individual vibration thresholds, changes in finger blood flow were correlated with thresholds (with both 0.5 and 1.5 ms Ϫ2 r.m.s. vibration): subjects with lower thresholds showed greater reductions in finger blood flow. Women had lower vibrotactile thresholds and showed greater vibration-induced reductions in finger blood flow. It is concluded that mechanoreceptors responsible for mediating vibration perception are involved in the vascular response to vibration.

Vibration of one hand can reduce finger blood flow and skin temperature on the unexposed hand, with the reduction dependent on temperature. The absolute reduction in FBF was greater with the higher room temperature, but the percentage reduction in FBF relative to FBF before vibration exposure was similar. Those with greater finger blood flow before vibration tend to have greater blood flow during vibration, and those with greater finger blood flow with one temperature tend to have greater blood flow with another temperature.