Circularly polarized differential intra-oral antenna design validation and characterization for tongue drive system.

Assistive devices are becoming increasingly popular for physically disabled persons suffering tetraplegia and spinal cord injuries. Intraoral tongue drive system (iTDS) is one of the most feasible and non-invasive assistive technology (AT), which utilises the transferring and inferring of user intentions through different tongue gestures. Wireless transferring is of prime importance and requires a suitable design of the intra-oral antenna. In this paper, a compact circularly polarized differential intra-oral antenna is designed, and its performance is analysed within heterogeneous multilayer mouth and head models. It works at 2.4 GHz in the Industrial, Scientific, and Medical (ISM) band. The footprint of the differential antenna prototype is 0.271 λg [Formula: see text] 0.271 λg [Formula: see text] 0.015 λg. It is achieved using two pairs of spiral segments loaded in diagonal form near the edges of the central rotated square slot and a high dielectric constant substrate. Its spiral-slotted geometry further provides the desired swirling and miniaturization at the desired frequency band for both mouth scenarios. Additionally, corner triangular slits on the radiating patch assist in tuning the axial ratio (< 3 dB) in the desired ISM band. To validate the performance of the proposed in-mouth antenna, the measurement was carried out using the minced pork and the saline solution for closed and opened mouth cases, respectively. The measured - 10 dB impedance bandwidth and peak gain values in the minced pork are from 2.28 to 2.53 GHz (10.39%) and - 18.17 dBi, respectively, and in the saline solution, are from 2.3 to 2.54 GHz (9.92%) and - 15.47 dBi, respectively. Further, the specific absorption rate (SAR) is estimated, and the data communication link is computed with and without a balun loss. This confirms that the proposed differential intraoral antenna can establish direct interfacing at the RF front end of the intraoral tongue drive system.

Distortion energy-electronic energy compensation determines the nature of solute interactions with irradiation induced vacancies in ferritic steel.

Fundamental knowledge of vacancy-solute atom (in particular, Cu and Ni) interactions at the electronic level is of utmost importance to understand experimentally observed Cu-precipitation in reactor pressure vessel (RPV) steel. In the present investigation, using first-principles electronic structure calculations within the framework of density functional theory (DFT), we unravel the nature of such interactions between a vacancy (V) or di-vacancy and solute atoms (mainly Cu and Ni) in the bcc-Fe lattice. One of the very novel features of the present investigation is that we demonstrate the importance of distortion energy-electronic energy compensation in stabilizing the formation of vacancy-Cu and vacancy-Ni clusters in ferritic steel. Further decomposition of the electronic energy contribution into different bonding contributions in conjugation with differential charge density analyses clearly reveals the origin of stability as a consequence of mutual compensation of different energy modes. For both Cu-Cu and Ni-Ni interactions, the presence of a vacancy leads to a more attractive interaction, implying that such vacancies generated due to irradiation make solute aggregation easier compared with the case of model steel with no defects. We have also demonstrated that the formation of CumNin clusters (m, n = 1, 5) is energetically favorable in addition to demonstrating that the stability increases with an increasing number of Cu or Ni atoms. The rate of increase of stability with the addition of solute atoms is higher in the case of the addition of Cu atoms into a Ni cluster than it is for adding Ni atoms into a Cu cluster. The present investigation thus provides a deeper electronic level understanding of solute-point defect interaction and cluster formation probability for Cu and Ni atoms in the ferritic steel.

An inexpensive microfluidic device for three-dimensional hydrodynamic focusing in imaging flow cytometry.

We present design, characterization, and testing of an inexpensive, sheath-flow based microfluidic device for three-dimensional (3D) hydrodynamic focusing of cells in imaging flow cytometry. In contrast to other 3D sheathing devices, our device hydrodynamically focuses the cells in a single-file near the bottom wall of the microchannel that allows imaging cells with high magnification and low working distance objectives, without the need for small device dimensions. The relatively large dimensions of the microchannels enable easy fabrication using less-precise fabrication techniques, and the simplicity of the device design avoids the need for tedious alignment of various layers. We have characterized the performance of the device with 3D numerical simulations and validated these simulations with experiments of hydrodynamic focusing of a fluorescently dyed sample fluid. The simulations show that the width and the height of the 3D focused sample stream can be controlled independently by varying the heights of main and side channels of the device, and the flow rates of sample and sheath fluids. Based on simulations, we also provide useful guidelines for choosing the device dimensions and flow rates for focusing cells of a particular size. Thereafter, we demonstrate the applicability of our device for imaging a large number of RBCs using brightfield microscopy. We also discuss the choice of the region of interest and camera frame rate so as to image each cell individually in our device. The design of our microfluidic device makes it equally applicable for imaging cells of different sizes using various other imaging techniques such as phase-contrast and fluorescence microscopy.

Magnetic ordering of the martensite phase in Ni-Co-Mn-Sn-based ferromagnetic shape memory alloys.

The magnetic state of low temperature martensite phase in Co-substituted Ni-Mn-Sn-based ferromagnetic shape memory alloys (FSMAs) has been investigated, in view of numerous conflicting reports of occurrences of spin glass (SG), superparamagnetism (SPM) or long range anti-ferromagnetic (AF) ordering. Combination of DC magnetization, AC susceptibility and small angle neutron scattering (SANS) studies provide clear evidence for AF order in the martensitic phase of Ni45Co5Mn38Sn12 alloy and rule out SPM and SG orders. Identical studies on another alloy of close composition, Ni44Co6Mn40Sn10, point to the presence of SG order in the martensitic phase and the absence of SPM behavior, contrary to earlier reports. SANS results do show the presence of nanometre-sized clusters but they are found to grow in size from 3 nm at 30 K to 11 nm at 300 K, and do not correlate with magnetism in these alloys.

Revisiting Temporal Evolution of Cu-Rich Precipitates in Fe-Cu Alloy: Correlative Small Angle Neutron Scattering and Atom-Probe Tomography Studies.

Binary Fe-Cu alloys are effective prototypes for investigating radiation-induced formation and growth of nanometric Cu-rich precipitates (CRPs) in nuclear reactor pressure vessels. In this report, the temporal evolution of CRPs during thermal aging of Fe-Cu binary alloys has been investigated by using complementary techniques such as atom probe tomography (APT) and small-angle neutron scattering (SANS). We report a detailed quantitative evolution of a rarely observed morphological transformation of Cu precipitates from spherical to ellipsoid with a significant change (approximately two times) in aspect ratio, an effect known to be associated with the 9R-3R structural transition of the precipitates. It is demonstrated through APT that the precipitates remain spherical up to 8 h, however, they subsequently convert to oblate ellipsoid upon further aging. SANS analysis also detected signs of this morphological transition in reciprocal space. Furthermore, SANS quantifies evolution of the precipitates and corroborates well with the APT results. Interestingly, the power-law exponent of the temporal evolution for mean size and number density agree reasonably well with the Lifshitz-Slyozov-Wagner model, in spite of the complex morphological evolution of the precipitates.

Unsupervised organization of cervical cells using bright-field and single-shot digital holographic microscopy.

We report results on unsupervised organization of cervical cells using microscopy of Pap-smear samples in brightfield (3-channel color) as well as high-resolution quantitative phase imaging modalities. A number of morphological parameters are measured for each of the 1450 cell nuclei (from 10 woman subjects) imaged in this study. The principal component analysis (PCA) methodology applied to this data shows that the cell image clustering performance improves significantly when brightfield as well as phase information is utilized for PCA as compared to when brightfield-only information is used. The results point to the feasibility of an image-based tool that will be able to mark suspicious cells for further examination by the pathologist. More importantly, our results suggest that the information in quantitative phase images of cells that is typically not used in clinical practice is valuable for automated cell classification applications in general.

Mice deficient in intestinal epithelium cytochrome P450 reductase are prone to acute toxin-induced mucosal damage.

Cytochrome P450 (P450) enzymes are a superfamily of heme-containing enzymes involved in the metabolism of various endogenous compounds, including retinoids, glucocorticoids, and eicosanoids, that are postulated to participate in the maintenance and/or development of inflammatory and immune reactions in the intestinal mucosa. To investigate the role of P450 enzymes in intestinal inflammation and immunity, we took advantage of IE-Cpr-null mice, which are deficient in intestinal epithelium of NADPH-cytochrome P450 reductase (CPR), the obligate redox partner of all microsomal P450 enzymes. We report that IE-Cpr-null mice, following an acute toxin challenge, had higher levels of pro-inflammatory chemokines and increased tissue damage compared to wild-type mice. IE-Cpr-null mice had normal Peyer's patch numbers and elicited normal secretory IgA (SIgA) responses. However, SIgA baseline levels in IE-Cpr-null mice were consistently elevated over WT littermates. While neither retinoic acid nor glucocorticoid levels in serum and intestinal homogenates were altered in IE-Cpr-null mice, basal levels of arachidonic acid metabolites (11,12-DiHETE and 14,15-DiHETE) with known anti-inflammatory property were significantly lower compared to WT controls. Overall, these findings reveal immunological and metabolic changes resulting from a genetic deficiency in CPR expression in the intestine, and support a role for microsomal P450 enzymes in mucosal homeostasis and immunity.

Three-dimensional reconstruction of murine Peyer's patches from immunostained cryosections.

Peyer's patches, macroscopic aggregates of lymphoid follicles present throughout the small intestines of humans and other mammals, are considered the gateway through which luminal dietary antigens and microbes are sampled by the mucosal immune system. The cellular make-up of Peyer's patch lymphoid follicles is not only complex, but highly dynamic, as there are at least four major cell types that are known to migrate in response to antigenic stimulation. In an effort to capture the complexity and dynamic nature of this specialized tissue, here we report the three-dimensional (3D) reconstruction of immunofluorescent-labeled mouse Peyer's patch cryosections. The technology that enabled the stacking and linear blending of serial cryosections was a novel macro for Fiji, the open source image-processing package based on ImageJ. By simultaneously labeling cryosections for surface markers CD45R, CD3, and CD11c, we provide a 3D image as well as quantitative measures of B-cell, T-cell, and dendritic cell populations at steady state and following exposure to the mucosal adjuvant cholera toxin.

Isolating and immunostaining lymphocytes and dendritic cells from murine Peyer's patches.

Peyer's patches (PPs) are integral components of the gut-associated lymphoid tissues (GALT) and play a central role in intestinal immunosurveillance and homeostasis. Particulate antigens and microbes in the intestinal lumen are continuously sampled by PP M cells in the follicle-associated epithelium (FAE) and transported to an underlying network of dendritic cells (DCs), macrophages, and lymphocytes. In this article, we describe protocols in which murine PPs are (i) dissociated into single cell suspensions and subjected to flow cytometry and (ii) prepared for cryosectioning and immunostaining. For flow cytometry, PPs are mechanically dissociated and then filtered through 70 µm membranes to generate single cell suspensions free of epithelial cells and large debris. Starting with 20-25 PPs (from four mice), this quick and reproducible method yields a population of >2.5 x 10(6) cells with >90% cell viability. For cryosectioning, freshly isolated PPs are immersed in Optimal Cutting Temperature (OCT) medium, snap-frozen in liquid nitrogen, and then sectioned using a cryomicrotome. Tissue sections (5-12 µm) are air-dried, fixed with acetone or methanol, and then subjected to immunolabeling.

Identification of small molecules that suppress ricin-induced stress-activated signaling pathways.

Ricin is a member of the ribosome-inactivating protein (RIP) family of plant and bacterial toxins. In this study we used a high-throughput, cell-based assay to screen more than 118,000 compounds from diverse chemical libraries for molecules that reduced ricin-induced cell death. We describe three compounds, PW66, PW69, and PW72 that at micromolar concentrations significantly delayed ricin-induced cell death. None of the compounds had any demonstrable effect on ricin's ability to arrest protein synthesis in cells or on ricin's enzymatic activity as assessed in vitro. Instead, all three compounds appear to function by blocking downstream stress-induced signaling pathways associated with the toxin-mediated apoptosis. PW66 virtually eliminated ricin-induced TNF-α secretion by J774A.1 macrophages and concomitantly blocked activation of the p38 MAPK and JNK signaling pathways. PW72 suppressed ricin-induced TNF-α secretion, but not p38 MAPK and JNK signaling. PW69 suppressed activity of the executioner caspases 3/7 in ricin toxin- and Shiga toxin 2-treated cells. While the actual molecular targets of the three compounds have yet to be identified, these data nevertheless underscore the potential of small molecules to down-regulate inflammatory signaling pathways associated with exposure to the RIP family of toxins.

ClpXP degrades SsrA-tagged proteins in Streptococcus pneumoniae.

Bacterial proteins that are abnormally truncated due to incomplete mRNA or the presence of rare codons are extended by an SsrA tag during ribosome rescue in a trans-translation process important for maintaining protein quality. In Escherichia coli, the SsrA-tagged proteins become the target of the Tsp, Lon, FtsH, ClpXP, and ClpAP proteases. Here we show that degradation of model SsrA-tagged proteins in Streptococcus pneumoniae depends primarily or exclusively on ClpXP in vivo. In addition, we show the E. coli SsrA tag is also a target of S. pneumoniae ClpXP in vivo, even though the N-terminal portions of the tags differ significantly between the two species, suggesting there may be no adaptor protein for SsrA in S. pneumoniae.