Memory effects in the relaxation of a confined granular gas

The accuracy of a model to describe the horizontal dynamics of a confined quasi-two-dimensional system of inelastic hard spheres is discussed by comparing its predictions for the relaxation of the temperature in an homogenous system with molecular dynamics simulation results for the original system. A reasonably good agreement is found. Next, the model is used to investigate the peculiarities of the nonlinear evolution of the temperature when the parameter controlling the energy injection is instantaneously changed while the system was relaxing. This can be considered as a non-equilibrium generalization of the Kovacs effect. It is shown that, in the low density limit, the effect can be accurately described by using a simple kinetic theory based on the first Sonine approximation for the one-particle distribution function. Some possible experimental implications are indicated

Homogeneous hydrodynamics of a collisional model of confined granular gases

The hydrodynamic equation governing the homogeneous time evolution of the temperature in a model of confined granular gas is studied by means of the Enskog equation. The existence of a normal solution of the kinetic equation is assumed as a condition for hydrodynamics. Dimensional analysis implies a scaling of the distribution function that is used to determine it in the first Sonine approximation, with a coefficient that evolves in time through its dependence on the temperature. The theoretical predictions are compared with numerical results obtained by the direct simulation Monte Carlo method, and a good agreement is found. The relevance of the normal homogeneous distribution function to derive inhomogeneous hydrodynamic equations, for instance using the Champan-Enskog algorithm, is indicated.Comment: Accepted in Phys. Rev.

Hydrodynamics for a model of a confined quasi-two-dimensional granular gas

The hydrodynamic equations for a model of a confined quasi-two-dimensional gas of smooth inelastic hard spheres are derived from the Boltzmann equation for the model, using a generalization of the Chapman-Enskog method. The heat and momentum fluxes are calculated to Navier-Stokes order, and the associated transport coefficients are explicitly determined as functions of the coefficient of normal restitution and the velocity parameter involved in the definition of the model. Also an Euler transport term contributing to the energy transport equation is considered. This term arises from the gradient expansion of the rate of change of the temperature due to the inelasticity of collisions, and vanishes for elastic systems. The hydrodynamic equations are particularized for the relevant case of a system in the homogeneous steady state. The relationship with previous works is analyzed

Edificios Colgados

Suspended buildings were first designed and constructed around the year 1965 in Holland and Germany, and since then they have been erected in various parts of the world. Altogether there are 17 of them at present. At the Plaza de Colón, in Madrid, the construction of the first two in Spain has been initiated, by the firm Osinalde, S, A. The author of the project is the architect Dr. Antonio Lámela, and Otep International, S. A. has collaborated in the study and calculation of the structure.Los edificios colgados comenzaron a proyectarse y construirse alrededor del año 1965, en los Países Bajos y Alemania, y desde entonces se han construido en diferentes partes del mundo, hasta un total de 17 en el momento actual. En la Plaza de Colón, de Madrid, se ha iniciado la construcción de los dos primeros en España, bajo la promoción de Osinalde, S. A. El autor del proyecto es el arquitecto Dr. Antonio Lámela, y ha colaborado en el estudio y cálculo de la estructura Otep Internacional, S. A

Forced synchronization of a quantum dissipative dynamics

We generalize the phenomenon of forced stochastic synchronization into the quantum domain within the framework of a paradigmatic spin-boson model (tunneling charge, or flipping spin 1/2 coupled to an environment) which is driven by an external periodic rectangular field. The overdamped regime of dissipative quantum tunneling is studied. Thermal noise assisted synchronization of a very high quality is shown to occur in a broad range of temperatures, driving strengths and frequencies, if the external driving frequency exceeds the zero-temperature limit of dissipative tunneling rate, the dissipation strength exceeds a critical value, and the driving is sufficiently strong. A simple criterion for such stochastic synchronization is established. Both the similarities and the profound differences with the akin phenomenon of quantum stochastic resonance are outlined.Ministerio de Educación y Ciencia (MEC). España FIS2005-0288

Cyttaria hariotii E.Fisch. as a promising source of pullulan and Mn(II)-pullulan complexes for Mn-deficiency remediation in winter cereals

Pullulan, a water-soluble polysaccharide consisting of maltotriose units used in the preparation of edible films and drug delivery, is generally produced from starch by Aureobasidium pullulans (de Bary & Löwenthal) G.Arnaud fungus. In this article, the characterisation of an alternative pullulan source - the stromata of Cyttaria hariotii E.Fisch. fungus - by elemental analysis, infrared spectroscopy and thermal analysis techniques is reported. With a view to a possible valorisation of this pullulan and its derivatives as bioactive formulations in agriculture, low-molecular-weight pullulan (<7 kDa) complexes with Mn(II), suitable for the remediation of Mn-deficiencies in winter cereal by foliar application, were synthesised and characterised by mass spectrometry

Physicochemical characterization and antimicrobial activity against Erwinia amylovora, Erwinia vitivora, and Diplodia seriata of a light purple Hibiscus syriacus L. Cultivar

Phytochemicals are essential raw materials for the production of formulations that can be helpful in crop protection. In particular, Hibiscus spp., which are often used in traditional medicine, are rich in potential bioactive molecules. This study presents an analysis of the thermal, vibrational, and phytochemical characteristics of a light purple variety of Hibiscus syriacus, using thermal gravimetric and differential scanning calorimetry, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectroscopy techniques. Further, with a view to its valorization, the antimicrobial activity of its extracts has been investigated in vitro against Erwinia amylovora (the phytopathogen responsible for fire blight in apples, pears, and some other members of the family Rosaceae), Erwinia vitivora (the causal agent of the “maladie d’Oléron” in grapevines), and Diplodia seriata (responsible for “Bot canker”). Higher heating values and thermal features showed similarities with kenaf biomass. The main compounds identified in the hydro-methanolic extracts were: in flowers, 1-heptacosanol, heptacosane, 1-tetracosanol, hexadecenoic acid, 9,12,15-octadecatrienoic acid, and 9,12-octadecadienoic acid; and in leaves, the coumarin derivative 4,4,6,8-tetramethyl-2-chromanone, vitamin E, phytol, and sitosterol. MIC values of 500 and 375 μg·mL−1 were obtained against E. amylovora for flower and leaf extracts, respectively, upon conjugation with chitosan oligomers (to improve solubility and bioavailability). In the case of E. vitivora, MIC values of 250 and 500 μg·mL−1, respectively, were registered. Regarding the antifungal activity, EC90 values of 975.8 and 603.5 μg·mL−1, respectively, were found. These findings suggest that H. syriacus (cv. ‘Mathilde’) may be a promising source of antimicrobials for agriculture

Antifungal activity of methylxanthines against grapevine trunk diseases

Methylxanthines, found in the seeds, leaves, and fruits of some plants, are receiving increasing attention as promising treatments for wood-degrading fungi. The aim of the study presented herein was to explore the potential applications of caffeine, four caffeine derivatives (viz. 8-bromo-caffeine, 8-iodo-caffeine, 8-(4-fluorophenoxy)-caffeine, and 8-(2, 3, 5, 6-tetrafluoroalcoxy)-caffeine), and theophylline as antifungals for Botryosphaeriaceae species associated with grapevine trunk diseases (GTDs). In vitro susceptibility tests were conducted to assess the antimycotic activity of the aforementioned compounds and their conjugated complexes with chitosan oligomers (COS). Caffeine, Br-caffeine, and I-caffeine exhibited higher efficacies than imidazole, the chosen antifungal control. Moreover, a strong synergistic behavior between COS and the methylxanthine derivatives was observed. The COS–I-caffeine complex showed the best overall performance against the phytopathogenic fungi with EC90 values of 471, 640, and 935 µg mL-1 for D. seriata, D. viticola, and N. parvum, respectively. In a second step, combinations of the new treatments with imidazole were also explored, resulting in further activity enhancement and EC90 values of 425, 271, and 509 mL-1 against D. seriata, D. viticola, and N. parvum, respectively, for the COS–I-caffeine-imidazole ternary compound. Given the high in vitro efficacy of these formulations for the control of GTDs, they may deserve further investigation with in vivo and field bioassays as an alternative to conventional fungicides. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Antifungal ativity against Botryosphaeriaceae fungi of the hydro-methanolic extract of Silybum marianum capitula conjugated with stevioside

Silybum marianum (L.) Gaertn, viz. milk thistle, has been the focus of research efforts in the past few years, albeit almost exclusively restricted to the medicinal properties of its fruits (achenes). Given that other milk thistle plant organs and tissues have been scarcely investigated for the presence of bioactive compounds, in this study, we present a phytochemical analysis of the extracts of S. marianum capitula during the flowering phenological stage (stage 67). Gas chromatography–mass spectroscopy results evidenced the presence of high contents of coniferyl alcohol (47.4%), and secondarily of ferulic acid ester, opening a new valorization strategy of this plant based on the former high-added-value component. Moreover, the application of the hydro-methanolic extracts as an antifungal agent has been also explored. Specifically, their activity against three fungal species responsible for the so-called Botryosphaeria dieback of grapevine (Neofusicoccum parvum, Dothiorella viticola and Diplodia seriata) has been assayed both in vitro and in vivo. From the mycelial growth inhibition assays, the best results (EC90 values of 303, 366, and 355 μg·mL−1 for N. parvum, D. viticola, and D. seriata, respectively) were not obtained for the hydroalcoholic extract alone, but after its conjugation with stevioside, which resulted in a strong synergistic behavior. Greenhouse experiments confirmed the efficacy of the conjugated complexes, pointing to the potential of the combination of milk thistle extracts with stevioside as a promising plant protection product in organic Viticulture

Schlafen 12 restricts HIV-1 latency reversal by a codon-usage dependent post-transcriptional block in CD4+ T cells

Latency is a major barrier towards virus elimination in HIV-1-infected individuals. Yet, the mechanisms that contribute to the maintenance of HIV-1 latency are incompletely understood. Here we describe the Schlafen 12 protein (SLFN12) as an HIV-1 restriction factor that establishes a post-transcriptional block in HIV-1-infected cells and thereby inhibits HIV-1 replication and virus reactivation from latently infected cells. The inhibitory activity is dependent on the HIV-1 codon usage and on the SLFN12 RNase active sites. Within HIV-1-infected individuals, SLFN12 expression in PBMCs correlated with HIV-1 plasma viral loads and proviral loads suggesting a link with the general activation of the immune system. Using an RNA FISH-Flow HIV-1 reactivation assay, we demonstrate that SLFN12 expression is enriched in infected cells positive for HIV-1 transcripts but negative for HIV-1 proteins. Thus, codon-usage dependent translation inhibition of HIV-1 proteins participates in HIV-1 latency and can restrict the amount of virus release after latency reversal. In cell lines and HIV-1 patient PBMCs, the Schlafen 12 protein (SLFN12) is shown to be an HIV-1 restriction factor that inhibits HIV-1 replication and virus reactivatio