Ballistic thermophoresis of adsorbates on free-standing graphene

The textbook thermophoretic force which acts on a body in a fluid is proportional to the local temperature gradient. The same is expected to hold for the macroscopic drift behavior of a diffusive cluster or molecule physisorbed on a solid surface. The question we explore here is whether that is still valid on a 2D membrane such as graphene at short sheet length. By means of a non-equilibrium molecular dynamics study of a test system -- a gold nanocluster adsorbed on free-standing graphene clamped between two temperatures $\Delta T$ apart -- we find a phoretic force which for submicron sheet lengths is parallel to, but basically independent of, the local gradient magnitude. This identifies a thermophoretic regime that is ballistic rather than diffusive, persisting up to and beyond a hundred nanometer sheet length. Analysis shows that the phoretic force is due to the flexural phonons, whose flow is known to be ballistic and distance-independent up to relatively long mean-free paths. Yet, ordinary harmonic phonons should only carry crystal momentum and, while impinging on the cluster, should not be able to impress real momentum. We show that graphene, and other membrane-like monolayers, support a specific anharmonic connection between the flexural corrugation and longitudinal phonons whose fast escape leaves behind a 2D-projected mass density increase endowing the flexural phonons, as they move with their group velocity, with real momentum, part of which is transmitted to the adsorbate through scattering. The resulting distance-independent ballistic thermophoretic force is not unlikely to possess practical applications

Reinforcement-learning-assisted quantum optimization

We propose a reinforcement learning (RL) scheme for feedback quantum control within the quantum approximate optimization algorithm (QAOA). We reformulate the QAOA variational minimization as a learning task, where an RL agent chooses the control parameters for the unitaries, given partial information on the system. Such an RL scheme finds a policy converging to the optimal adiabatic solution of the quantum Ising chain that can also be successfully transferred between systems with different sizes, even in the presence of disorder. This allows for immediate experimental verification of our proposal on more complicated models: The RL agent is trained on a small control system, simulated on classical hardware, and then tested on a larger physical sample

A case report of malignant hypertension in a young woman

8noMalignant hypertension is a condition characterized by severe hypertension and multi-organ ischemic complications. Albeit mortality and renal survival have improved with antihypertensive therapy, progression to end-stage renal disease remains a significant cause of morbidity and mortality. The underlying cause of malignant hypertension, which can be primary or secondary hypertension, is often difficult to identify and this can substantially affect the treatment outcomes, as we report here.openopenMichelli, Andrea; Bernardi, Stella; Grillo, Andrea; Panizon, Emiliano; Rovina, Matteo; Bardelli, Moreno; Carretta, Renzo; Fabris, BrunoMichelli, Andrea; Bernardi, Stella; Grillo, Andrea; Panizon, Emiliano; Rovina, Matteo; Bardelli, Moreno; Carretta, Renzo; Fabris, Brun

Friction anomalies at first-order transition spinodals: 1T-TaS2

Revealing phase transitions of solids through mechanical anomalies in the friction of nanotips sliding on their surfaces, a successful approach for continuous transitions, is still an unexplored tool for first-order ones. Owing to slow nucleation, first-order structural transformations occur with hysteresis, comprised between two spinodal temperatures where, on both sides of the thermodynamic transition, one or the other metastable free energy branches terminates. The spinodal transformation, a collective one-shot event without heat capacity anomaly, is easy to trigger by a weak external perturbation. Here we show that even the gossamer mechanical action of an AFM-tip can locally act as a trigger, narrowly preempting the spontaneous spinodal transformation, and making it observable as a nanofrictional anomaly. Confirming this expectation, the CCDW-NCCDW first-order transition of the important layer compound 1T-TaS2 is shown to provide a demonstration of this effect

Ruling out coronavirus disease 2019 in patients with pneumonia: The role of blood cell count and lung ultrasound

Coronavirus disease 2019 (COVID-19) is characterized by a distinctive blood leucocyte pattern and B-lines on lung ultrasound (LUS) as marker of alveolar-interstitial syndrome. We aimed to evaluate the accuracy of blood leucocyte count alone or in combination with LUS for COVID-19 diagnosis. We retrospectively enrolled consecutive patients diagnosed with community acquired pneumonia (CAP) at hospital admission to derive and validate cutoff values for blood cell count that could be predictive of COVID-19 before confirmation by the nucleic acid amplification test (NAAT). Cutoff values, generated and confirmed in inception (41/115, positive/negative patients) and validation (100/180, positive/negative patients) cohorts, were ≤17 and ≤10 cells/mm3 for basophils and eosinophils, respectively. Basophils and/or eosinophils below cutoff were associated with sensitivity of 98% (95%CI, 94–100) and negative likelihood ratio of 0.04 (95%CI, 0.01–0.11). In a subgroup of 265 subjects, the sensitivity of B-line on LUS was 15% lower (p < 0.001) than that of basophils and/or eosinophils below cutoff. The combination of B-lines with basophils and eosinophils below cutoff was associated with a moderate increase of the positive likelihood ratio: 5.0 (95%CI, 3.2–7.7). In conclusion, basophil and eosinophil counts above the generated cutoff virtually rule out COVID-19 in patients with CAP. Our findings can help optimize patient triage pending the NAAT results

Study of structures and thermodynamics of CuNi nanoalloys using a new DFT-fitted atomistic potential

Shape, stability and chemical ordering patterns of CuNi nanoalloys are studied as a function of size, composition and temperature. A new parametrization of an atomistic potential for CuNi is developed on the basis of ab initio calculations. The potential is validated against experimental bulk properties, and ab initio results for nanoalloys of sizes up to 147 atoms and for surface alloys. The potential is used to determine the chemical ordering patterns of nanoparticles with diameters of up to 3 nm and different structural motifs (decahedra, truncated octahedra and icosahedra), both in the ground state and in a wide range of temperatures. The results show that the two elements do not intermix in the ground state, but there is a disordering towards solid-solution patterns in the core starting from room temperature. This order-disorder transition presents different characteristics in the icosahedral, decahedral and fcc nanoalloys

Epidemiology of atherosclerotic cardiovascular disease in polygenic hypercholesterolemia with or without high lipoprotein(a) levels

Background and aimsEpidemiology of atherosclerotic cardiovascular disease might be different in patients with polygenic hypercholesterolemia plus high levels (≥30 mg/dl) of Lp(a) (H-Lpa) than in those with polygenic hypercholesterolemia alone (H-LDL). We compared the incidence of peripheral artery disease (PAD), coronary artery disease (CAD), and cerebrovascular disease (CVD) in patients with H-Lpa and in those with H-LDL.MethodsRetrospective analysis of demographics, risk factors, vascular events, therapy, and lipid profile in outpatient clinical data. Inclusion criteria was adult age, diagnosis of polygenic hypercholesterolemia, and both indication and availability for Lp(a) measurement.ResultsMedical records of 258 patients with H-Lpa and 290 H-LDL were reviewed for occurrence of vascular events. The median duration of follow-up was 10 years (IQR 3–16). In spite of a similar reduction of LDL cholesterol, vascular events occurred more frequently, and approximately 7 years earlier (P = 0.024) in patients with H-Lpa than in H-LDL (HR 1.96 1.21–3.17, P = 0.006). The difference was around 10 years for acute events (TIA, Stroke, acute coronary events) and one year for chronic ones (P = 0.023 and 0.525, respectively). Occurrence of acute CAD was higher in H-Lpa men (HR 3.1, 95% CI 1.2–7.9, P = 0.007) while, among women, PAD was observed exclusively in H-Lpa subjects with smoking habits (P = 0.009).ConclusionsPatients with high Lp(a) levels suffer from a larger and earlier burden of the disease compared to those with polygenic hypercholesterolemia alone. These patients are at higher risk of CAD if they are men, and of PAD if they are women

Macroinvertebrate community biomonitoring of a public water supply reservoir in southern Brazil

The faunal inventory of the macroinvertebrate community is important to the environmental assessment, since this biota is sensitive to human disturbance. The reservoir of Rio Verde, located on the first plateau of Paraná, is inserted into an agricultural region with several forest fragments Araucaria. The aim of this study was to evaluate the environmental integrity of the reservoir through ecological indexes of macroinvertebrate community benthic and associated with macrophytes. Five sampling points were defined in the study area, which comprise distinct microhabitats in the basin. There were four sampling campaigns, each by weather station: Spring (2014); Summer (2015); Autumn (2015) and Winter (2015). In each sample were measured abiotic various parameters in the field and be collected water samples for nutrient analysis in the laboratory. The macroinvertebrates were collected in triplicate at adapted Macan method using mesh sieve 1 mm and CPUE (catch per unit effort) for 20 minutes. In order to pellet sample was used a dredger model Petersen 2L. Still in the field, by season, samples were collected from macrophytes Myriophyllum aquaticum (Vell) Verdc. and Potamogeton montevidensis A. Benn. in triplicates in the fluvial region of the reservoir, to analyze the associated fractal dimension and macrofauna. For this we used a PVC sampler specific volume 0.025 m3. the following ecological descriptors were calculated in each case: abundance, wealth tax, wealth Margalef, Shannon-Wiener diversity, evenness evenness through the Past software. The index Biological Monitoring Working Party (BMWP) for monitoring sampling points was also calculated. Regarding the statistical analysis, we used the analysis of PERMANOVA to compare points and seasons and canonical correspondence analysis (CCoA) for variables. Regarding M. aquaticum and P. montevidensis it was not verified difference to the average associated macroinvertebrates. However there was a difference for abundance of organisms in the fractal dimension and biomass of specimens. M. aquaticum is more complex and took more macrofauna in relation to P. montevidensis. Regarding the monitoring of the reservoir, it showed up mesotrophic with moderate nutrient concentrations and within the regulatory limits. Benthic macrofauna showed statistical differences in relation to the reservoir region, sample point and temporal variation. The BMWP index showed that the river region has the highest biotic integrity (in all samples above 70 points), and the ecological descriptors of wealth and Margalef diversity of Shannon- Wiener higher. In point 4 (dam downstream) were recorded evidence of possible impacts due to lower wealth and BMWP index which resulted in a questionable quality water. New approaches are needed to focus on the aquatic community in the best understanding of this ecosystem and also with a view to environmental preservation of the Green River Basin.CAPESO inventário faunístico da comunidade de macroinvertebrados aquáticos é importante ao diagnóstico ambiental, uma vez que esta biota é sensível a perturbações antrópicas. O reservatório do Rio Verde, situado no primeiro planalto paranaense, está inserido em uma região agrícola que apresenta diversos fragmentos de Floresta com Araucária. O objetivo do presente estudo foi avaliar a integridade ambiental do reservatório através de índices ecológicos da comunidade de macroinvertebrados bênticos e associados à macrófitas aquáticas. Foram delimitados cinco pontos amostrais na área de estudo, os quais compreendem microhabitats distintos na bacia hidrográfica. Realizaram-se quatro campanhas amostrais, cada uma por estação climática: primavera (2014); verão (2015); outono (2015) e inverno (2015). Em cada coleta foram mensurados diversos parâmetros abióticos em campo e coletaram-se amostras de água para análise de nutrientes em laboratório. Os macroinvertebrados foram coletados em triplicatas pelo método de Macan adaptado, utilizando-se peneiras de malha 1 mm e CPUE (Captura por unidade de esforço) de 20 minutos. Para amostra do sedimento utilizou-se uma draga modelo Petersen de 2L. Ainda em campo, por estação, foram coletadas amostras das macrófitas aquáticas Myriophyllum aquaticum (Vell) Verdc. e Potamogeton montevidensis A. Benn. em triplicatas na região fluvial do reservatório, para análise da macrofauna associada e dimensão fractal. Para tal foi utilizado um amostrador de PVC específico com volume 0,025 m3. Foram calculadas os seguintes descritores ecológicos em cada caso: abundância, riqueza de taxa, riqueza de Margalef, diversidade de Shannon-Wiener, equitabilidade de Pielou através do software Past. Também foi calculado o índice Biological Monitoring Working Party (BMWP) para monitoramento dos pontos amostrais. Em relação às análises estatísticas, foram utilizadas as análises de PERMANOVA para comparação entre pontos e estações climáticas e análise de correspondência canonica (CCA) para variáveis. Em relação a M. aquaticum e P. montevidensis não foi verificada diferença entre a riueza de macroinvertebrados associados. Contudo houve diferença para abundância de organismos, na dimensão fractal e biomassa dos exemplares. M. aquaticum é mais complexa e abrigou mais macrofauna em relação a P. montevidensis. Em relação ao monitoramento do reservatório, este apresentou-se mesotrófico com concentrações de nutrientes moderadas e dentro dos limites normativos. A macrofauna bêntica apresentou diferenças estatísticas em relação a região do reservatório, ponto amostral e variação temporal. O índice de BMWP mostrou que a região fluvial apresenta a maior integridade biótica (em todas as coletas acima dos 70 pontos), bem como os descritores ecológicos de riqueza de Margalef e diversidade de Shannon-Wiener mais elevados. No ponto 4 (jusante da barragem) foram registradas evidências de possíveis impactos em função da riqueza menos elevada e pelo índice de BMWP o qual resultou em uma água de qualidade duvidosa. São necessárias novas abordagens com foco na comunidade aquática visando o melhor entendimento deste ecossistema e também com vistas a preservação ambiental da bacia do Rio Verde