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Abstract Biological tissues, sediments, or engineered systems are spatially structured media with a tortuous and porous structure that host the flow of fluids. Such complex environments can influence the spatial and temporal colonization patterns of bacteria by controlling the transport of individual bacterial cells, the availability of resources, and the distribution of chemical signals for communication. Yet, due to the multi-scale structure of these complex systems, it is hard to assess how different biotic and abiotic properties work together to control the accumulation of bacterial biomass. Here, we explore how flow-mediated interactions allow the gut commensal Escherichia coli to colonize a porous structure that is composed of heterogenous dead-end pores (DEPs) and connecting percolating channels, i.e. transmitting pores (TPs), mimicking the structured surface of mammalian guts. We find that in presence of flow, gradients of the quorum sensing (QS) signaling molecule autoinducer-2 (AI-2) promote E. coli chemotactic accumulation in the DEPs. In this crowded environment, the combination of growth and cell-to-cell collision favors the development of suspended bacterial aggregates. This results in hot-spots of resource consumption, which, upon resource limitation, triggers the mechanical evasion of biomass from nutrients and oxygen depleted DEPs. Our findings demonstrate that microscale medium structure and complex flow coupled with bacterial quorum sensing and chemotaxis control the heterogenous accumulation of bacterial biomass in a spatially structured environment, such as villi and crypts in the gut or in tortuous pores within soil and filters.

Abstract Chemical weathering associated with dissolution/precipitation at interfaces between minerals and flowing fluids is key for the evolution of geologic systems, including groundwater contamination and storage capacity. Relying on Atomic Force Microscopy (AFM) yields reaction rates at nanoscale resolutions. Challenges limiting our ability to quantify heterogeneity associated with these processes include establishing reliable platforms allowing AFM imaging of real‐time and in situ absolute material fluxes across mineral surfaces under continuous flow conditions to complement typically acquired surface topography images. We provide an experimental workflow and heterogeneous absolute rates at the nanoscale across the surface of a calcite crystal under dissolution. These high‐quality experimental observations are then interpreted through a stochastic approach. The latter is geared to embed diverse kinetic modes driving the degree of spatial heterogeneity of the reaction and corresponding to different mechanistic processes documented across the crystal surface.

Here we propose to exploit the natural instability of thin solid films, i.e. solid state dewetting, to form regular patterns of monocrystalline atomically smooth Si, Si1-xGex and Ge nanostructures that cannot be realized with conventional methods. Additionally, the solid-state dewetting dynamics is guided by pre-patterning the sample by a combination of electron-beam lithography and reactive-ion etching, obtaining precise control over number, size, shape, and relative position of the final structures. Methods and structures will be optimized towards their exploitation mainly in photonic devices application (e.g. anti-reflection coatings, colour-filters, random lasers, quantum emitters and photonic sensors).

Polarization control through all-dielectric metasurfaces holds great potential in different fields, such as telecommunications, biochemistry and holography. Asymmetric chiral metasurfaces supporting quasi-bound states in the continuum may prove very useful for controlling and manipulating the polarization state of light. A crucial quantity for characterizing the optical chirality is the circular dichroism (CD). In this work we analyse how the CD and quality factor of the optical mode can be strongly influenced by a nanofabrication error. Modelling the nanofabrication uncertainties on the gaps of the chiral metasurface, the imperfections of the etchings process or the modification of the asymmetry factor, we found that the proper engineering of the gap between the nanostructures of the unit cell is the most important parameter to achieve a high-quality factor and enhanced optical dichroism. An optimization of the nanofabrication processes, such as dose factor, dwell time and plasma etching demonstrates that, for a writing field of 100 μm2, it is possible to obtain morphologically precise chiral metasurfaces, with fabrication uncertainties lower than those that would limit Q factor and chirality property.

We report on photoinduced inverse spin-Hall effect (ISHE) measurements as a function of the incident photon energy in the 4–50 K temperature range for a Pt/n-doped Si junction. Optical spin injection allows generating a spin-oriented population of electrons and holes around the Δ valleys and Γ point of the Si Brillouin zone, respectively. Spin-polarized carriers cross the Pt/Si contact and then enter the Pt overlayer, where spin-to-charge conversion occurs by means of spin-dependent scattering with Pt nuclei. For temperatures T up to 20 K, most of the dopants are not ionized, so that the electric field, stemming from the contact potential between Pt and Si, extends to the whole Si substrate, which becomes insulating, and only spin-oriented holes reach the Pt layer and contribute to the ISHE spectra. For T > 20 K, donors are partially ionized, and the resulting space charge close to the Pt/Si interface leads to the formation of a Schottky contact where the electric field rapidly vanishes within a few micrometers. As a consequence, also spin-polarized electrons enter Pt by means of thermionic emission, contributing to the ISHE signal. We numerically solve the one-dimensional spin drift-diffusion equations for holes and electrons and estimate the temperature dependence of the spin lifetime in Si for both populations, demonstrating that Si may serve as a versatile platform for spintronic applications, able to leverage both electrons and holes. [ABSTRACT FROM AUTHOR]

Despite innovative approaches to urban food production, skepticism towards vertical crops remains widespread, posing profitability risks for agricultural enterprises. To overcome these challenges and develop successful business models, identifying consumer acceptance barriers is crucial for engaging stakeholders, investors, and farmers in local food production. When introducing innovative food production methods, like vertical farming, it is essential to gain public approval. However, recent technological advancements, such as genetically modified crops and artificial radiation, have been met with doubt, leaving overall consumer opinions about vertical farming uncertain. In this context, the purpose of this paper is to analyze Italian consumers’ acceptance of vertical farming systems and products, aiming to understand the main drivers that influence their desire to purchase such products. The research, conducted in Italy from April to May 2023, gathered qualitative and quantitative data through an anonymous online questionnaire that was completed by potential consumers. A total of 258 respondents were eligible for data analysis. The survey assessed participants’ knowledge, attitudes towards agriculture and food, and perceptions of vertical farming using Likert scale evaluations. The findings showed that, although a large proportion of respondents expressed interest in purchasing vertical farming products, concerns related to cost, authenticity, and environmental sustainability pose challenges. The evidence that emerged provides a series of indications for understanding consumer preferences more in-depth and useful suggestions for companies that need to expand the vertical farming products market.

We have developed a non-local architecture for spin current injection, manipulation, and detection in n-doped bulk Si at room temperature. Spins are locally generated at the indirect gap of bulk Si by means of circularly polarized light and then detected by exploiting the inverse spin-Hall effect (ISHE) occurring inside a thin Pt pad deposited at the top of the Si substrate. We demonstrate that it is possible to modulate the transport properties of the optically injected spin current by applying a bias voltage along the direction of motion of the particles. In this case, we are able to explore both the spin diffusion regime, characterized by a spin diffusion length Ls ≈ 12 μm, and the spin drift regime with applied electric fields up to E = 35 V/cm. We demonstrate that the spin transport length of the electrons can be increased (or decreased) by more than 100% for electric fields antiparallel (or parallel) to the diffusion direction. As a consequence, the ISHE signal can be electrically controlled to have high or low output voltages from the non-local device.

Infection with the protozoan parasite Toxoplasma gondii occurs worldwide and usually causes no symptoms. However, a primary infection of pregnant women, may infect the fetus by transplacental transmission. The risk of mother-to-child transmission depends on week of pregnancy at the time of maternal infection: it is low in the first trimester, may reach 90% in the last days of pregnancy. Inversely, however, fetal disease is more severe when infection occurs early in pregnancy than later. Systematic serologic testing in pregnant women who have no antibodies at the beginning of pregnancy, can accurately reveal active maternal infection. Therefore, the risk of fetal infection should be assessed and preventive treatment with spiramycin must be introduced as soon as possible to reduce the risk of mother-to-child transmission, and the severity of fetal infection. When maternal infection is confirmed, prenatal diagnosis with Polymerase Chain Reaction (PCR) on amniotic fluid is recommended. If fetal infection is certain, the maternal treatment is changed to a combination of pyrimethamine-sulfonamide and folinic acid. Congenitally infected newborns are usually asymptomatic at birth, but at risk for tardive sequelae, such as blindness. When congenital infection is evident, disease include retinochoroiditis, cerebral calcifications, hydrocephalus, neurocognitive impairment. The diagnosis of congenital infection must be confirmed at birth and management, specific therapy, and follow-up with multidisciplinary counseling, must be guaranteed.

In recent decades, the literature on food risk has grown significantly. Consumers are increasingly interested in being informed about the relationship between the food they purchase, their health, and current sustainability goals. In this study, university students' opinions on food quality attributes were collected through a survey in search of emerging common traits and taking into account the students' socio-demographic characteristics. The sample for the analysis consists of 5133 students enrolled at the University of Turin (Italy), whose perceptions of food risk are analyzed using hierarchical cluster analysis and principal component analysis. The results reveal the existence of four clusters within the surveyed student population: "Detached", "Warranty-oriented", "Inattentive", and "Made in Italy-oriented". In particular, the analysis shows a significant influence of age, education level, income, and employment on students' preferences concerning the purchasing process and food safety. The results also provide some suggestions to stakeholders, underlying the necessity to strengthen the knowledge of the origin of food products and the awareness of the challenges of the global–local food system. [ABSTRACT FROM AUTHOR]

Islamic finance and Islamic banking have been the subject of central scientific interest, as demonstrated by the significant increase in publications on the subject in recent years. In the present paper, the use of the bibliometric analytical technique is proposed to examine the research on Islamic finance. The objective of the study consists in carrying out a bibliometric analysis of all the publications on Scopus relative to Islamic finance. The parameters used include the type of document (article), the language of publication (English). Among other things, the author, the publication models, the distribution of the thematic category, the distribution of the author's key words, the country of publication and the most frequently cited article are analyzed. The different rankings reinforce the fact that bibliometric understanding of scientific impact is a multidimensional construct. However, the bibliometric analysis does not take place in an institutional and political vacuum. The institutional context of quality evaluation of public and private research increasingly determines which metrics are applied, with consequent effects on performance evaluation. Through analysis, citation rates are proposed, and the impact factors of journals are quantitative and objective indicators directly linked to published science. The objective of this paper is to identify the future trend of research in the field of Islamic finance.