Explosively Formed Projectile Soft-Recovery Force Analysis

The design of a soft-recovery system is critical to a researcher\u27s ability to analyze hypervelocity projectiles. The researcher may decide to use one method over another based on several criteria, including whether or not non-deformed projectile measurements are required. This report analyzes the forces two different soft-recovery methods impart on the projectiles collected. Method 1 utilized three polyethylene water barrels placed “end-to-end” horizontally, providing 2.6 meters (9 feet) of water to stop the projectile. Method 2 is a modification of the soft-recovery method utilized in “Soft-Recovery of Explosively Formed Penetrators” by Lambert and Pope. This method utilizes a series of several materials with an increasing density gradient, placed end-to-end over 14.3 meters (47 feet) to stop the projectile. Despite the fact that explosively formed projectiles (EFPs) of the same design were fired into each recovery method, the projectiles collected using the two methods differed in shape, size, weight, and the number of pieces collected. Since the EFP designs were identical to begin with, the physical differences are most likely due to the different magnitudes of the forces exerted on the projectile during deceleration. Drag force calculations will be performed for both recovery methods in an attempt to determine the differences in the drag forces exerted on the projectile during its deceleration. The results of the calculations will assist in determining to what extent the physical deformation of the projectile is due to the material selection of each recovery method. The consistency of the shapes and weights of the recovered projectiles will also be briefly addressed to assist the researcher in choosing the most useful recovery method for a given objective

The Effects of the Flyer Plate\u27s Radius of Curvature on the Performance of an Explosively Formed Projectile

An explosively formed projectile (EFP) is known for its ability to penetrate vehicle armor effectively. Understanding how an EFP’s physical parameters affect its performance is crucial to development of armor capable of defeating such devices. The present study uses two flyer plate radii of curvature to identify the experimental effects of the flyer plate’s radius of curvature on the measured projectile velocity, depth of penetration, and projectile shape. The Gurney equation is an algebraic relationship for estimating the velocity imparted to a metal plate in contact with detonating explosives. The authors of this research used a form of the Gurney equation to calculate the theoretical flyer plate velocity. Two EFP designs that have different flyer plate radii of curvature, but the same physical parameters and the same flyer-weight to charge-weight ratio should theoretically have the same velocity. Tests indicated that the flyer plate’s radius of curvature does not affect the projectile’s velocity and that a flat flyer plate negatively affects projectile penetration and formation

SARS-CoV-2 antibodies detected in human breast milk postvaccination

Importance The SARS-CoV-2 pandemic has infected over a hundred million people worldwide, with almost 2.5 million deaths at the date of this publication. In the United States, Pfizer-BioNTech and Moderna vaccines were first administered to the public starting in December 2020, and no lactating women were included in the initial trials of safety/efficacy. Research on SARS-CoV-2 vaccination in lactating women and the potential transmission of passive immunity to the infant through breast milk is needed to guide patients, clinicians and policy makers during the worldwide effort to curb the spread of this virus. Objective To determine whether SARS-CoV-2 specific immunoglobins are found in breast milk post-vaccination, and to characterize the time course and types of immunoglobulins present. Design Prospective cohort study Setting Providence Portland Medical Center, Oregon, USA Participants Six lactating women who planned to receive both doses of the Pfizer-BioNTech or Moderna vaccine between December 2020 and January 2021. Breast milk samples were collected pre-vaccination and at 11 additional timepoints, with last sample at 14 days post 2nd dose of vaccine. Exposure Two doses of Pfizer-BioNTech or Moderna SARS-CoV-2 vaccine. Main Outcome(s) and Measure(s) Levels of SARS-CoV-2 specific IgA and IgG immunoglobulins in breast milk. Results In this cohort of 6 lactating women who received 2 doses of SARS-CoV-2 vaccine, we observed significantly elevated levels of SARS-CoV-2 specific IgG and IgA antibodies in breast milk beginning at Day 7 after the initial vaccine dose, with an IgG-dominant response. Conclusions and Relevance We are the first to show that maternal vaccination results in SARS-CoV-2 specific immunoglobulins in breast milk that may be protective for infants. Competing Interest Statement The authors have declared no competing interest. Funding Statement This work was supported by generous grants from Nancy Lematta (BAF) and the Chiles Foundation (BAF)

Note: Autonomous Pulsed Power Generator Based on Transverse Shock Wave Depolarization of Ferroelectric Ceramics

Autonomous pulsed generators utilizing transverse shock wave depolarization (shock front propagates across the polarization vector P0) of Pb(Zr0.52Ti0.48)O3 poled piezoelectric ceramics were designed, constructed, and experimentally tested. It was demonstrated that generators having total volume of 50 cm3 were capable of producing the output voltage pulses with amplitude up to 43 kV with pulse duration 4 µs. A comparison of high-voltage operation of transverse and longitudinal shock wave ferroelectric generators is given

Adenomatous Polyposis Coli is Present Near the Minimal Level Required for Accurate Graded Responses to the Wingless Morphogen

The mechanisms by which the Wingless (Wg) morphogen modulates the activity of the transcriptional activator Armadillo (Arm) to elicit precise, concentration-dependent cellular responses remain uncertain. Arm is targeted for proteolysis by the Axin/Adenomatous polyposis coli (Apc1 and Apc2)/Zeste-white 3 destruction complex, and Wg-dependent inactivation of destruction complex activity is crucial to trigger Arm signaling. In the prevailing model for Wg transduction, only Axin levels limit destruction complex activity, whereas Apc is present in vast excess. To test this model, we reduced Apc activity to different degrees, and analyzed the effects on three concentration-dependent responses to Arm signaling that specify distinct retinal photoreceptor fates. We find that both Apc1 and Apc2 negatively regulate Arm activity in photoreceptors, but that the relative contribution of Apc1 is much greater than that of Apc2. Unexpectedly, a less than twofold reduction in total Apc activity, achieved by loss of Apc2, decreases the effective threshold at which Wg elicits a cellular response, thereby resulting in ectopic responses that are spatially restricted to regions with low Wg concentration. We conclude that Apc activity is not present in vast excess, but instead is near the minimal level required for accurate graded responses to the Wg morphogen

Rubble Pile Characterization Model

Rubble piles created following the collapse of a building in a combat situation can significantly impact mission accomplishment, particularly in the area of movement and maneuver. Rubble characteristics must be known, for example, in order to predict the ability of a vehicle to override the collateral damage from weapon effects in urban areas. Two types of models are developed: a first-order model and a first-principles-based model. In both models, we assume complete rubblization of the building and develop a rubble profile model using the size and composition of the collapsed structure to predict the rubble volume. In both cases, this profile model includes the size of the footprint area surrounding the original building assuming that the rubble is free to expand horizontally as well as the resulting height of such a rubble pile. Empirical data is now needed to verify the predictive capabilities of these models

Ovarian Cancer Progression is Controlled by Phenotypic Changes in Dendritic Cells

We characterized the initiation and evolution of the immune response against a new inducible p53-dependent model of aggressive ovarian carcinoma that recapitulates the leukocyte infiltrates and cytokine milieu of advanced human tumors. Unlike other models that initiate tumors before the development of a mature immune system, we detect measurable antitumor immunity from very early stages, which is driven by infiltrating dendritic cells (DCs) and prevents steady tumor growth for prolonged periods. Coinciding with a phenotypic switch in expanding DC infiltrates, tumors aggressively progress to terminal disease in a comparatively short time. Notably, tumor cells remain immunogenic at advanced stages, but anti-tumor T cells become less responsive, whereas their enduring activity is abrogated by different microenvironmental immunosuppressive DCs. Correspondingly, depleting DCs early in the disease course accelerates tumor expansion, but DC depletion at advanced stages significantly delays aggressive malignant progression. Our results indicate that phenotypically divergent DCs drive both immunosurveillance and accelerated malignant growth. We provide experimental support for the cancer immunoediting hypothesis, but we also show that aggressive cancer progression after a comparatively long latency period is primarily driven by the mobilization of immunosuppressive microenvironmental leukocytes, rather than loss of tumor immunogenicity