Multiscale model of a freeze–thaw process for tree sap exudation

Sap transport in trees has long fascinated scientists, and a vast literature exists on experimental and modelling studies of trees during the growing season when large negative stem pressures are generated by transpiration from leaves. Much less attention has been paid to winter months when trees are largely dormant but nonetheless continue to exhibit interesting flow behaviour. A prime example is sap exudation, which refers to the peculiar ability of sugar maple (Acer saccharum) and related species to generate positive stem pressure while in a leafless state. Experiments demonstrate that ambient temperatures must oscillate about the freezing point before significantly heightened stem pressures are observed, but the precise causes of exudation remain unresolved. The prevailing hypothesis attributes exudation to a physical process combining freeze–thaw and osmosis, which has some support from experimental studies but remains a subject of active debate. We address this knowledge gap by developing the first mathematical model for exudation, while also introducing several essential modifications to this hypothesis. We derive a multiscale model consisting of a nonlinear system of differential equations governing phase change and transport within wood cells, coupled to a suitably homogenized equation for temperature on the macroscale. Numerical simulations yield stem pressures that are consistent with experiments and provide convincing evidence that a purely physical mechanism is capable of capturing exudation.     

Fermentative aptitude of non-Saccharomyces wine yeast for reduction in the ethanol content in wine

Over the last few decades, there has been a progressive increase in the ethanol content in wines due to global climate change and to the new wine styles that are associated with increased grape maturity. This increased ethanol content can have negative consequences on the sensory properties of the wines, human health, and economic aspects. Several microbiological approaches for decreasing the ethanol content have been suggested, such as strategies based on genetically modified yeasts, the adaptive evolution of yeasts, and the use of non-Saccharomyces yeast. In the present study, we investigated the interspecies and intraspecies variability of some non-Saccharomyces wine yeast species under anaerobic fermentation conditions. Across different grape juices and fermentation trials, Hanseniaspora uvarum, Zygosaccharomyces sapae, Zygosaccharomyces bailii, and Zygosaccharomyces bisporus promoted significant reductions in ethanol yield and fermentation efficiency in comparison with Saccharomyces cerevisiae. The diversion of alcoholic fermentation and the abundant formation of secondary compounds might explain the marked reduction in ethanol yield, as determined through the segregation of the majority of the strains according to their species attributes observed using principal component analysis. These data suggest that careful evaluation of interspecies and intraspecies biodiversity can be carried out to select yeast that produces low-ethanol yields.     

Numerical study of cell morphology effects on convective heat transfer in reticulated ceramics

Understanding the influence of foam morphology on the heat transport mechanism is an essential task for the design engineers. The assessment of foam thermal properties was performed using experimental techniques or simulation approaches such as Finite Elements analysis and/or computational fluid dynamics and was, up to now, mainly focused on describing the influence of some average parameters, such as cell size and porosity. Recent numerical analysis have instead demonstrated that local cell morphological structures can strongly influence thermal conduction in ceramic foams. Therefore, in the present work, the effect of morphological characteristics, namely ligament radius, cell inclination angle and ligament tapering, on the convective heat transfer of ceramic foams were studied. The approach used is Computational Fluid Dynamics (CFD) and foam geometries were schematically represented with tetrakaydecahedra geometries. The numerical simulations, performed with ANSYS/Fluent on different tetrakaydecahedra geometries, aimed at evaluating pressure drop and heat exchange through the foam. A heat exchanger efficiency parameter was defined and then evaluated for the different foam geometries at several air flow velocities. Results show the influence of the different morphological parameters and, in particular, that the heat exchanger efficiency of the foams decreases when increasing the air flow velocity.     

Liquid Biopsy for Cancer Cachexia: Focus on Muscle-Derived microRNAs

Cancer cachexia displays a complex nature in which systemic inflammation, impaired energy metabolism, loss of muscle and adipose tissues result in unintentional body weight loss. Cachectic patients have a poor prognosis and the presence of cachexia reduces the tolerability of chemo/radio-therapy treatments and it is frequently the primary cause of death in advanced cancer patients. Early detection of this condition could make treatments more effective. However, early diagnostic biomarkers of cachexia are currently lacking. In recent years, although solid biopsy still remains the “gold standard” for diagnosis of cancer, liquid biopsy is gaining increasing interest as a source of easily accessible potential biomarkers. Moreover, the growing interest in circulating microRNAs (miRNAs), has made these molecules attractive for the diagnosis of several diseases, including cancer. Some muscle-derived circulating miRNA might play a pivotal role in the onset/progression of cancer cachexia. This topic is of great interest since circulating miRNAs might be easily detectable by means of liquid biopsies and might allow an early diagnosis of this syndrome. We here summarize the current knowledge on circulating muscular miRNAs involved in muscle atrophy, since they might represent easily accessible and promising biomarkers of cachexia.     

Deflection behaviour of FRP reinforced concrete beams and slabs: An experimental investigation

The flexural response of FRP RC elements is investigated through load–deflection tests on 24 RC beams and slabs with glass FRP (GFRP) and carbon FRP (CFRP) reinforcement covering a wide range of reinforcement ratios. Rebar and concrete strains around a crack inducer are used to establish moment–curvature relationships and evaluate the shear and flexural components of mid-span deflections. It is concluded that the contribution of shear and bond induced deformations can be of major significance in FRP RC elements having moderate to high reinforcement ratios. Existing equations to calculate short-term deflection of FRP RC elements are discussed and compared to experimental values.     

Cultivar and growing area effects on minor compounds of olive oil from autochthonous and European introduced cultivars in Tunisia

BACKGROUND: Antioxidant profile and volatile compounds were characterized in three virgin olive oils from European countries introduced and cultivated under the same orchard conditions in comparison to some autochthonous cultivars planted in different areas of Tunisia. RESULTS: Significant differences were observed between the oils. α‐Tocopherol content is more important in autochthonous Tunisian cultivars (cvs), higher (400 mg kg^?1) than in European cvs. Total phenols showed that Chétoui cv. (grown in Zaghouan) had the highest level (446 mg kg^?1), followed by Koroneiki (403 mg kg^?1) and Chétoui cvs (grown in Béja) (398 mg kg^?1). Koroneiki oils had the highest content of (3,4‐dihydroxyphenyl)ethanol and (p‐hydroxyphenyl)ethanol (20.5 and 43.5 mg kg^?1, respectively), whereas (3,4‐dihydroxyphenyl)ethanol was not detected in Arbequina, Arbosana or Chemlali cvs (grown in Sahel). Chétoui cv. presented the highest content of dialdehydic form of decarboxymethyl elenolic acid linked to (3,4‐dihydroxyphenyl)ethanol (171 mg kg^?1), whereas Chemlali (Sahel) cv. had the lowest content (29.6 mg kg^?1). The volatile compounds showed an increase in C6 compounds and decrease in pentene isomers in olive oils from varieties cultivated in other growing areas. CONCLUSION: Virgin olive oils studied demonstrate that the differences in phenols, tocopherol levels and volatile profiles may be explained by genetic factors and geographic areas, particularly altitude. Copyright © 2009 Society of Chemical Industry     

Encapsulating Eu3+ complex doped layers to improve Si‐based solar cell efficiency

This paper reports the electrical characterization of commercially available crystalline silicon solar cells encapsulated with poly‐vinylacetate doped with different Eu³⁺ organic complexes. The inclusion of these complexes in the encapsulating matrix allows down‐shifting of the solar spectrum components below 420 nm toward the maximum quantum efficiency of the solar cells. This effect has been proven under Air Mass 1·5 conditions (simulating terrestrial applications) where an increase of the total power delivered by the encapsulated cells has been observed. Moreover, this enhancement has been obtained using very low percentage by weight of organolanthanide dopants, allowing a reduction in the Watt peak price. At higher concentrations a strong quenching of the energy transfer from the organic antenna to the lanthanide ion has been observed. Copyright © 2009 John Wiley & Sons, Ltd.     

Einige Mehle und Brote aus Hungergegenden Russlands

Ohne Zusammenfassung     

DOG1 as an Immunohistochemical Marker of Acinic Cell Carcinoma: A Systematic Review and Meta-Analysis

DOG1 is a transmembrane protein originally discovered on gastrointestinal stromal tumors and works as a calcium-activated chloride channel protein. There are a limited number of articles on the potential utility of this antibody in the diagnosis of salivary gland tumors in routine practice. In this study, we aimed to investigate the role of DOG1 as an immunohistochemical marker in patients with salivary acinic cell carcinoma (ACC) through meta-analysis. A literature search was performed of the PubMed, Scopus, and Web of Science databases for English-language studies published from January 2010 to September 2021. The literature search revealed 148 articles, of which 20 were included in the study. The overall rate of DOG1 expression in salivary acinic cell carcinoma was 55% (95% CI = 0.43–0.58). Although ACC is a challenging diagnosis, paying careful attention to the cytomorphological features in conjunction with DOG1 immunostaining can help to reach an accurate diagnosis.