Use of Nanoparticles as Nanoelectrodes in Contact-Less Cell Membrane Permeabilization by Time-Varying Magnetic Field: A Computational Study

This paper describes a computational approach for the assessment of electric field enhancement by using highly conductive gold nanoparticles (Au NPs) in time-varying electromagnetic fields cell membrane permeabilization, estimating the influence of the presence of Au NPs on transmembrane potential and on the pore opening dynamics. To account for variability and uncertainty about geometries and relative placement and aggregations of the Au NPs, three different NP configurations were considered: spherical Au NPs equally spaced around the cell; cubic Au NPs, for accounting for the possible edge effect, equally spaced around the cell; and spherical Au NPs grouped in clusters. The results show that the combined use of Au NPs and a time-varying magnetic field can significantly improve the permeabilization of cell membranes. The variability of NPs’ geometries and configurations in proximity of the cell membrane showed to have a strong influence on the pore opening mechanism. The study offers a better comprehension of the mechanisms, still not completely understood, underlying cell membrane permeabilization by time-varying magnetic fields.

A Novel Simulation Platform for Underwater Data Muling Communications Using Autonomous Underwater Vehicles

Autonomous Underwater Vehicles (AUVs) are seen as a safe and cost-effective platforms for performing a myriad of underwater missions. These vehicles are equipped with multiple sensors which, combined with their long endurance, can produce large amounts of data, especially when used for video capturing. These data need to be transferred to the surface to be processed and analyzed. When considering deep sea operations, where surfacing before the end of the mission may be unpractical, the communication is limited to low bitrate acoustic communications, which make unfeasible the timely transmission of large amounts of data unfeasible. The usage of AUVs as data mules is an alternative communications solution. Data mules can be used to establish a broadband data link by combining short-range, high bitrate communications (e.g., RF and wireless optical) with a Delay Tolerant Network approach. This paper presents an enhanced version of UDMSim, a novel simulation platform for data muling communications. UDMSim is built upon a new realistic AUV Motion and Localization (AML) simulator and Network Simulator 3 (ns-3). It can simulate the position of the data mules, including localization errors, realistic position control adjustments, the received signal, the realistic throughput adjustments, and connection losses due to the fast SNR change observed underwater. The enhanced version includes a more realistic AML simulator and the antenna radiation patterns to help evaluating the design and relative placement of underwater antennas. The results obtained using UDMSim show a good match with the experimental results achieved using an underwater testbed. UDMSim is made available to the community to support easy and faster evaluation of underwater data muling oriented communications solutions and to enable offline replication of real world experiments.

Circularly Polarized Dual-Band LoRa/GPS Antenna for a UAV-Assisted Hazardous Gas and Aerosol Sensor

UAV assisted wireless sensor networks play a key role in the detection of toxic gases and aerosols. UAVs can be used to remotely deploy sensor nodes and then collect gas concentration readings and GPS positioning from them to delimit an affected area. For such purpose, a dual-band communication system is required, supporting GPS reception, and sensor reading data transfer, which is chosen to be at 2.4 GHz using LoRa physical layer. In this work we propose a switched-beam antenna subsystem for the sensor nodes capable not only of satisfying the dual band requirements but also of maximizing communication range or energy consumption through a good antenna polarization match and improved antenna gain. This antenna subsystem is built using dual-port, dual-band, circularly polarized antenna elements, whose design and experimental validation is carefully detailed. A low profile microstrip stacked structure has been used to obtain return loss in both bands better than 15 dB, axial ratios below 1.5 dB, and wide −3 dB beamwidths around 90° and 75° for GPS and 2.4 GHz bands, respectively, thus limiting the gain reduction of the switched-beam system in critical sensor orientations. Special attention has been paid to reduce the coupling between both ports through the optimization of the relative placement of both patches and their feeding points. The measured coupling is below −30 dB.

Foster Care, Permanency, and Risk of Prison Entry

Objective: (1) Examine associations of foster care exit type (e.g., reunification with birth family, adoption, guardianship/permanent relative placement, or emancipation from care) with risk of entry into state prison; (2) Examine racial disparities in those associations. Method: With data on over 10,000 Wisconsin youth who entered foster care in mid- to late-childhood, we present imprisonment rates in young adulthood by race, sex, and foster care exit type. Proportional hazards models with a robust set of covariates compared prison entry rates among the most common exit types—reunification, aging out, and guardianship/permanent relative placement. Results: Nearly 13 percent of the sample experienced imprisonment in young adulthood. Compared with emancipated youth, hazard of imprisonment was 1.58–1.96 times higher among reunified youth. Differences were largely unexplained by observed individual, family, or foster care characteristics. Imprisonment rates were similar for emancipated youth and youth exiting to guardianship/permanent relative placement. Hazard of imprisonment for reunified Black youth was twice that of reunified white youth, but racial differences in prison entry were statistically non-significant among emancipated youth. Conclusion: Efforts to reduce incarceration risk for all youth in foster care are needed. Reunified youth may benefit from services and supports currently provided primarily to emancipated youth.

Kannimar Shrines and Iconography

The Kannimar are seven look-alike goddesses affiliated with the Pleiades. In local Tamil folk temples of Tamilnadu’s Kongu area they are worshipped in one cluster, as sisters. They are mediators who occupy a middle ground, both spatially and ritually. The seven are served together, soon after the most prominent gods and goddesses, but ahead of other deities, mainly devotees and service-providers whose shrines are found in the same broad compound. The seven Kannimar provide a key bridge linking local to pan-Indian belief traditions. Their role resembles that of certain women in the human sphere, where it is common for a mother to mediate between father and son, or for a sister to bridge the awkward gap between her family of birth and that of her in-laws. The Kannimar also operate as handmaidens dedicated to the service of the great goddess K?l?. They are her loyal communicators and errand runners. These seven females are youthful charmers, but they are also fierce womb-guardians who have nurturing powers and awesome resurrection abilities. The relative placement of the Kannimar within the local folk universe, can offer us multiple insights into a wide range of human and divine relationships expressed through the Hindu pantheon.

The five-analyzer point-to-point scanning crystal spectrometer at ESRF ID26

X-ray emission spectroscopy in a point-to-point focusing geometry using instruments that employ more than one analyzer crystal poses challenges with respect to mechanical design and performance. This work discusses various options for positioning the components and provides the formulas for calculating their relative placement. Ray-tracing calculations were used to determine the geometrical contributions to the energy broadening including the source volume as given by the beam footprint on the sample. The alignment of the instrument is described and examples are given for the performance.

Very few sites can reshape the inferred phylogenetic tree

The history of animal evolution, and the relative placement of extant animal phyla in this history is, in principle, testable from phylogenies derived from molecular sequence data. Though datasets have increased in size and quality in the past years, the contribution of individual genes (and ultimately amino acid sites) to the final phylogeny is unequal across genes. Here we demonstrate that removing a small fraction of sites strongly favoring one topology can produce a highly-supported tree of an alternate topology. We explore this approach using a dataset for animal phylogeny, and create a highly-supported tree with a monophyletic group of sponges and ctenophores, a topology not usually recovered. Because of the high sensitivity of such an analysis to gene selection, and because most gene sets are neither standardized nor representative of the entire genome, researchers should be diligent about making intermediate analyses available with their phylogenetic studies. Effort is needed to ensure these datasets are maximally informative, by ensuring all genes are systematically sampled across relevant species. From there, it could be determined whether any gene or gene sets introduce bias, and then deal with those biases appropriately.

Feasibility Study of an Automated Assembly Process for Ultrathin Chips

This paper presents a feasibility study of an automated pick-and-place process for ultrathin chips on a standard automatic assembly machine. So far, scientific research about automated assembly of ultrathin chips, with thicknesses less than 50 µm, is missing, but is necessary for cost-effective, high-quantity production of system-in-foil for applications in narrow spaces or flexible smart health systems applied in biomedical applications. Novel pick-and-place tools for ultrathin chip handling were fabricated and a process for chip detachment from thermal release foil was developed. On this basis, an adhesive bonding process for ultrathin chips with 30 µm thickness was developed and transferred to an automatic assembly machine. Multiple ultrathin chips aligned to each other were automatically placed and transferred onto glass and polyimide foil with a relative placement accuracy of ±25 µm.

Capillary Impregnation of Viscous Fluids in a Multi-Layered Porous Medium

Capillary impregnation of viscous fluids in porous media is useful in diagnostics, design of lab-on-chip devices and enhanced oil recovery. The impregnation of a wetting fluid in a homogeneous porous medium follows Washburn’s diffusive law. The diffusive dynamics predicts that, with the increase in permeability, the rate of spontaneous imbibition of a wetting fluid also increases. As most of the naturally occurring porous media are composed of hydrodynamically interacting layers having different properties, the impregnation in a heterogeneous porous medium is significantly different from a homogeneous porous medium. A Washburn like model has been developed in the past to predict the imbibition behavior in the layers for a hydrodynamically interacting three layered porous medium filled with a non-viscous resident phase. It was observed that the relative placement of the layers impacts the imbibition phenomena significantly. In this work, we develop a quasi one-dimensional lubrication approximation to predict the imbibition dynamics in a hydrodynamically interacting multi-layered porous medium. The generalized model shows that the arrangement of layers strongly affects the saturation of wetting phase in the porous medium, which is crucial for oil recovery and in microfluidic applications.

kCSD-python, a tool for reliable current source density estimation

Kernel Current Source Density (kCSD), which we introduced in 2012, is a kernel-based method to estimate current source density (CSD) from extracellular potentials recorded with arbitrarily placed electrodes. Estimating reconstruction errors in CSD has been an outstanding challenge. To address it, here we revisit kCSD and explore its mathematical underpinnings. First, we quantify the information that can be recovered from extracellular recordings for a given setup, by introducing eigensources — a set of basic CSD profiles, which form the basis of estimation space. Next, we investigate the effect of relative placement of basis sources and electrodes on the reconstruction fidelity. We show that the correct distribution of sources is crucial for the reconstruction, in particular, CSD reconstruction is possible even for badly misplaced electrodes. We also introduce L-curve, a new method for choosing reconstruction parameters, in addition to the previously used cross-validation. Finally, we propose two types of diagnostics of reconstruction veracity, error propagation map and reliability map. For any given setup, the error propagation map indicates how the electrode noise propagates to the reconstructed CSD and the reliability map illustrates the point-wise reliability of kCSD estimation. The kCSD method and the additional techniques introduced here are implemented in kCSD-python, a new Python package provided under an open license. kCSD-python’s features and usage are highlighted with a jupyter notebook tutorial. This new tool can perform CSD estimations for 1D, 2D, and 3D electrode setups, assuming distributions of sources in a tissue, a slice, or in a single cell.