Anomalous permeation of the [P5W30O110 ]15- polyoxoanion in polyelectrolyte multilayer films

International audienceThe integration of polyoxoanions into functional thin films is of major interest to increase their use as catalysts or to provide new properties to the films. The incorporation of polyoxoanions in polyelectrolyte multilayer (PEM) films has been widely used for such aims. In most investigations, the polyoxoanions were used as a component of the layering process and there is only limited work investigating the interactions of polyoxoanions with preformed PEM films. Herein, we investigated the incorporation of the 30-tungsto-5-phosphate [P 5 W 30 O 110 ] 152 polyoxoanion into PEM films made from hyaluronic acid (HA) and poly(allylamine hydrochloride) (PAH) as a function of the polyoxoanion's concentration. Surprisingly, we found an increased amount of incorporated [P 5 W 30 O 110 ] 152 upon a decrease in its bulk concentration. Confocal Raman microscopy allowed us to investigate the concentration profile of the polyoxoanion across films of about 3 mm in thickness. Homogeneous distribution was only found for films fed with polyoxoanions at the lowest bulk concentration, namely 1.2 6 10 26 M, whereas the films fed with solutions at higher concentrations (1.2 6 10 24 M) showed local enrichment in POM at the film-solution interface. We explain the lower amount of incorporated polyoxoanion at high bulk concentration by the formation of a polyoxoanion-rich barrier reducing further diffusion of the anions in the deeper part of the films

Par3 integrates Tiam1 and phosphatidylinositol 3-kinase signaling to change apical membrane identity

Pathogens can alter epithelial polarity by recruiting polarity proteins to the apical membrane, but how a change in protein localization is linked to polarity disruption is not clear. In this study, we used chemically induced dimerization to rapidly relocalize proteins from the cytosol to the apical surface. We demonstrate that forced apical localization of Par3, which is normally restricted to tight junctions, is sufficient to alter apical membrane identity through its interactions with phosphatidylinositol 3-kinase (PI3K) and the Rac1 guanine nucleotide exchange factor Tiam1. We further show that PI3K activity is required upstream of Rac1, and that simultaneously targeting PI3K and Tiam1 to the apical membrane has a synergistic effect on membrane remodeling. Thus, Par3 coordinates the action of PI3K and Tiam1 to define membrane identity, revealing a signaling mechanism that can be exploited by human mucosal pathogens

Deposition Mechanism and Properties of Thin Polydopamine Films for High Added Value Applications in Surface Science at the Nanoscale

Polydopamine films have been introduced by Messersmith et al. as a possible “versatile” surface functionalization method allowing to coat the surface of almost all known materials even superhydrophobic surfaces. These new kinds of coatings also confer a plethora of functionalities to the coated materials owing to the complex chemistry of the catechol quinone moieties present on the surface of polydopamine. These coatings may hence become an interesting alternative to established surface coatings like self-assembled monolayers and polyelectrolyte multilayered films. In this review, we describe the knowledge acquired in the last 3 years about the deposition mechanisms of polydopamine films, their properties, and various applications in surface science at the nanoscale.Fonds Europeen de Developpement Economique et Regional (Chaptochem Project 2009-02-039-35

Dynamic Mechanical Properties of PMMA/Organoclay Nanocomposite: Experiments and Modeling

Similarly to unfilled polymers, the dynamic mechanical properties of polymer/organoclay nanocomposites are sensitive to frequency and temperature, as well as to clay concentration

PowerCool: Simulation of Integrated Microfluidic Power Generation in Bright Silicon MPSoCs

Integrated microfluidic power generation and power delivery promises to be a disruptive packaging technology with the potential to combat dark silicon. It essentially consists of integrated microchannel-based electrochemical “flow cells” in a 2D/3D multiprocessor system-on-chip (MPSoC), that generate electricity to power up the entire or part of the chip, while also simultaneously acting as a high-efficiency microfluidic heat sink. Further development of this technology requires efficient modeling tools that would assess the efficacy of such solutions and help perform early-stage design space exploration. In this paper, we propose a compact mathematical model, called Power- Cool, that performs electro-chemical modeling and simulation of integrated microfluidic power generation in MPSoCs. The accuracy of the model has been validated against fine-grained multiphysics simulations of flow cells in the COMSOL software that is unsuitable for EDA because of large simulation times. PowerCool model is demonstrated to be up to 425x times faster than COMSOL simulations while incurring a worst-case error of only 5%. Furthermore, the PowerCool model has been used to study and assess the efficacy of this technology for a test MPSoC

Integrated Microfluidic Power Generation and Cooling for Bright Silicon MPSoCs

The soaring demand for computing power in our digital information age has produced as collateral undesirable effect a surge in power consumption and heat density for computing servers. Accordingly, 30-40% of the energy consumed in state-of-the-art servers is dissipated in cooling. The remaining energy is used for computation, and causes the temperature ramp-up to operating conditions that already preclude operating all the cores at maximum performance levels, in order to prevent system overheating and failures. This situation is set to worsen as shipments of high-end (i.e., even denser) many-core servers are increasing at a 25% compound annual growth rate. Thus, state-of-the-art worst-case power and cooling delivery solutions on servers are reaching their limits and it will no longer be possible to power up simultaneously all the available on-chip cores (situation known as the existence of "dark silicon"); hence, drastically limiting the benefits of technology scaling. This presentation aims to completely revise the prevailing worst-case power and cooling provisioning paradigm for servers by championing a disruptive approach to computing server architecture design that prevents dark silicon. This proposed approach integrates a flexible heterogeneous many-core architecture template with an on-chip microfluidic fuel cell network for joint cooling delivery and power supply (i.e., local power generation and delivery), as well as a holistic power-temperature model predictive controller exploiting the server software stack, in order to achieve scalable and energy-minimal server architectures. Thanks to the disruptive system-level many-core architecture with microfluidic power and cooling delivery, as well as the complementary temperature control, we can envision the removal of the current limits of power delivery and heat dissipation in server designs, subsequently avoiding dark silicon in future servers and enabling new perspectives in future energy-proportional server designs

PowerCool: Simulation of Cooling and Powering of 3D MPSoCs with Integrated Flow Cell Arrays

Integrated Flow-Cell Arrays (FCAs) represent a combination of integrated liquid cooling and on-chip power generation, converting chemical energy of the flowing electrolyte solutions to electrical energy. The FCA technology provides a promising way to address both heat removal and power delivery issues in 3D Multiprocessor Systems-on-Chips (MPSoCs). In this paper we motivate the benefits of FCA in 3D MPSoCs via a qualitative analysis and explore the capabilities of the proposed technology using our extended PowerCool simulator. PowerCool is a tool that performs combined compact thermal and electrochemical simulation of 3D MPSoCs with inter-tier FCA-based cooling and power generation. We validate our electrochemical model against experimental data obtained using a micro-scale FCA, and extend PowerCool with a compact thermal model (3D-ICE) and subthreshold leakage estimation. We show the sensitivity of the FCA cooling and power generation on the design-time (FCA geometry) and run-time (fluid inlet temperature, flow rate) parameters. Our results show that we can optimize the FCA to keep maximum chip temperature below 95 °C for an average chip power consumption of 50 W/cm2 while generating up to 3.6 W per cm2 of chip area

What is the relationship between worker skills and outcomes for families in child and family social work?

Communication skills are fundamental to social work, yet few studies have directly evaluated their impact. In this study, we explore the relationship between skills and outcomes in 127 families. An observation of practice was undertaken on the second or third meeting with a family. Practice quality was evaluated in relation to seven skills, which were grouped into three dimensions: relationship building, good authority and evocation of intrinsic motivation. Outcomes at approximately six months were parent-reported engagement (Working Alliance Inventory), Goal Attainment Scaling (GAS), an eleven-point family life satisfaction rating, the Family Environment Scale and General Health Questionnaire and service outcomes from agency records including children entering care. Relationship-building skills predicted parent-reported engagement, although good authority and evocation had stronger relationships with outcome measures. Where workers visited families more often, relationships between skills and outcomes were stronger, in part because workers had more involvement and in part because these families were more likely to have significant problems. The relationship between skills and outcomes was complicated, although the findings provide encouraging evidence that key social work skills have an influence on outcomes for families

HIV Productively Infects Highly Differentiated and Exhausted CD4+ T Cells During AIDS

Background: Throughout HIV infection, productively infected cells generate billions of viral particles and are thus responsible for body-wide HIV dissemination, but their phenotype during AIDS is unknown. As AIDS is associated with immunological changes, analyzing the phenotype of productively infected cells can help understand HIV production during this terminal stage. Methods: Blood samples from 15 untreated viremic participants (recent infection, n=5; long-term infection, n=5; active opportunistic AIDS-defining disease, n=5) and 5 participants virologically controlled on antiretroviral therapy (ART) enrolled in the Analysis of the Persistence, Reservoir and HIV Latency (APRIL) study (NCT05752318) were analyzed. Cells expressing the capsid protein p24 (p24+ cells) after 18 hours of resting or 24 hours of stimulation (HIV-Flow) revealed productively infected cells from viremic participants or translation-competent reservoir cells from treated participants, respectively. Results: The frequency of productively infected cells tended to be higher during AIDS in comparison with recent and long-term infections (median, 340, 72, and 32/million CD4+ T cells, respectively) and correlated with the plasma viral load at all stages of infection. Altogether, these cells were more frequently CD4low, HLA-ABClow, CD45RA-, Ki67+, PD-1+, with a non-negligible contribution from pTfh (CXCR5+PD-1+) cells, and were not significantly enriched in HIV coreceptors CCR5 nor CXCR4 expression. The comparison markers expression between stages showed that productively infected cells during AIDS were enriched in memory and exhausted cells. In contrast, the frequencies of infected pTfh were lower during AIDS compared to non-AIDS stages. A UMAP analysis revealed that total CD4+ T cells were grouped in 7 clusters and that productive p24+ cells were skewed to given clusters throughout the course of infection. Overall, the preferential targets of HIV during the latest stages seemed to be more frequently highly differentiated (memory, TTD-like) and exhausted cells and less frequently pTfh-like cells. In contrast, translation-competent reservoir cells were less frequent (5/million CD4+ T cells) and expressed more frequently HLA-ABC and less frequently PD-1. Conclusions: In long-term infection and AIDS, productively infected cells were differentiated and exhausted. This could indicate that cells with these given features are responsible for HIV production and dissemination in an immune dysfunction environment occurring during the last stages of infection

Safety attitudes culture remain stable in a transplant center: evidence from the coronavirus pandemic

BackgroundWe sought to understand how safety culture may evolve during disruption, by using the COVID-19 pandemic as an example, to identify vulnerabilities in the system that could impact patient outcomes.MethodsA cross-sectional analysis of transplant personnel at a high-volume transplant center was conducted using the Safety Attitudes Questionnaire (SAQ). Survey responses were scaled and evaluated pre- and post-COVID-19 (2019 and 2021).ResultsTwo-hundred and thirty-eight responses were collected (134 pre-pandemic and 104 post-pandemic). Represented organ groups included: kidney (N = 89;38%), heart (N = 18;8%), liver (N = 54;23%), multiple (N = 66;28%), and other (N = 10;4%). Responders primarily included nurses (N = 75;34%), administration (N = 50;23%), and physicians (N = 24;11%). Workers had high safety, job satisfaction, stress recognition, and working conditions satisfaction (score >75) both before and after the pandemic with overlapping responses across both timepoints. Stress recognition, safety, and working conditions improved post-COVID-19, but teamwork, job satisfaction, and perceptions of management were somewhat negatively impacted (all p > 0.05).ConclusionsDespite the serious health care disruptions induced by the pandemic, high domain ratings were notable and largely maintained in a high-volume transplant center. The SAQ is a valuable tool for healthcare units and can be used in longitudinal assessments of transplant culture of safety as a component of quality assurance and performance improvement initiatives