899 research outputs found
Vibrational spectroscopic profiling of biomolecular interactions between oak powdery mildew and oak leaves
Oak powdery mildew, caused by the biotrophic fungus Erysiphe alphitoides, is a prevalent disease affecting oak trees, such as English oak (Quercus robur). While mature oak populations are generally less susceptible to this disease, it can endanger young oak seedlings and new leaves on mature trees. Although disruptions of photosynthate and carbohydrate translocation have been observed, accurately detecting and understanding the specific biomolecular interactions between the fungus and the leaves of oak trees is currently lacking. Herein, via hybrid Raman spectroscopy combined with an advanced artificial neural network algorithm, the underpinning biomolecular interactions between biological soft matter, i.e., Quercus robur leaves and Erysiphe alphitoides, are investigated and profiled, generating a spectral library and shedding light on the changes induced by fungal infection and the tree's defence response. The adaxial surfaces of oak leaves are categorised based on either the presence or absence of Erysiphe alphitoides mildew and further distinguishing between covered or not covered infected leaf tissues, yielding three disease classes including healthy controls, non-mildew covered and mildew-covered. By analysing spectral changes between each disease category per tissue type, we identified important biomolecular interactions including disruption of chlorophyll in the non-vein and venule tissues, pathogen-induced degradation of cellulose and pectin and tree-initiated lignification of cell walls in response, amongst others, in lateral vein and mid-vein tissues. Via our developed computational algorithm, the underlying biomolecular differences between classes were identified and allowed accurate and rapid classification of disease with high accuracy of 69.6% for non-vein, 73.5% for venule, 82.1% for lateral vein and 85.6% for mid-vein tissues. Interfacial wetting differences between non-mildew covered and mildew-covered tissue were further analysed on the surfaces of non-vein and venule tissue. The overall results demonstrated the ability of Raman spectroscopy, combined with advanced AI, to act as a powerful and specific tool to probe foliar interactions between forest pathogens and host trees with the simultaneous potential to probe and catalogue molecular interactions between biological soft matter, paving the way for exploring similar relations in broader forest tree-pathogen systems.</p
Editorial: Anticoagulation in cardiovascular diseases: evolving role, unmet needs, and grey areas
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Strong-mixing induced deep ocean heat uptake events in the North Atlantic.
The deceleration of the upper ocean heat storage during the last decade has resulted in an active search for the
’missing heat’ in the deep ocean. Modeling work has provided new insights into the role of the central Pacific
Ocean on the present hiatus in global warming and the efficient transfer of heat to the deep ocean, but recent
studies have highlighted also the large contribution of the North Atlantic basin to these processes, mainly based on
ocean observations. The deep ocean heat uptake (below 300 m) in the North Atlantic is not confined to the subpolar
gyre region but extends to mid-latitudes of the Eastern North Atlantic (ENA), requiring an additional process for its
explanation other than deep convection considered until now. Here, using oceanographic in-situ data, we describe a
mechanism of heat and salt injection to the deep ocean after years of warming and saltening at the surface occurred
both in regions of mode (43º-48ºN) and deep water (74º-76ºN) formation in the ENA. The mechanism, although
punctual meditated by strong winter mixing events, is between 2 and 6 times higher than the 2000-2010 ocean
heat uptake at depths of mode (300-700m) and deep water (>2000m) formation, contributing significantly to the
observed deep ocean heat uptake in the North Atlantic. Nutrient, hydrographic and reanalysis data indicate that
the strong mixing-induced deep ocean heat uptake events at areas of mode and deep water formation in the North
Atlantic are connected through the northward propagation of salty ENA mode waters triggered by the contraction
of the subpolar gyre reinforced by the occurrences of blocking anomalies in the ENA. Such connection is not
unique of the last decade but observed also during the 1960s. Natural climate variability seems the ultimate driver
of the strong mixing-induced deep ocean heat uptake events, although the anthropogenic global warming and its
forcing on the Arctic sea-ice retreat and frequency of extreme weather events could modify their effects.0,000
Synthesizing SystemC Code from Delay Hybrid CSP
Delay is omnipresent in modern control systems, which can prompt oscillations
and may cause deterioration of control performance, invalidate both stability
and safety properties. This implies that safety or stability certificates
obtained on idealized, delay-free models of systems prone to delayed coupling
may be erratic, and further the incorrectness of the executable code generated
from these models. However, automated methods for system verification and code
generation that ought to address models of system dynamics reflecting delays
have not been paid enough attention yet in the computer science community. In
our previous work, on one hand, we investigated the verification of delay
dynamical and hybrid systems; on the other hand, we also addressed how to
synthesize SystemC code from a verified hybrid system modelled by Hybrid CSP
(HCSP) without delay. In this paper, we give a first attempt to synthesize
SystemC code from a verified delay hybrid system modelled by Delay HCSP
(dHCSP), which is an extension of HCSP by replacing ordinary differential
equations (ODEs) with delay differential equations (DDEs). We implement a tool
to support the automatic translation from dHCSP to SystemC
Venous thromboembolism in COVID-19 patients
We read with interest the study published by Tang and coll.1 in a recent issue of the Journal of Thrombosis and Haemostasis. In this retrospective analysis, conducted at the Tongji Hospital of Wuhan, China, it is reported that heparin treatment reduces mortality in subjects affected by severe COVID-19 who have \u201csepsis-induced coagulopathy\u201d. The definition of severe COVID-19 was the presence of at least one of following: respiratory rate 6530 breaths /min; arterial oxygen saturation 6493% at rest; PaO2/FiO2 64300 mmHg. The Authors of this study also reported that, among subjects not treated with heparin, mortality raised according with D-dimer levels. Of note, patients that received heparin in this study were mostly treated with enoxaparin, at the thromboprophylactic dose of 40-60 mg/day, for at least 7 days
Performance Assessment and Mathematical Modeling of Process Parameters in Electrical Discharge Machining of EN-31 Tool Steel Material Using Taguchi DOE
In non-traditional machining, electrical discharge machining (EDM) has tremendous potential on account of versatility of its applications and is successfully, commercially used in modern industries. EDM process is capable to machine geometrically complex, hard material components, tool steels, composites, super alloys, ceramics and carbides. In EDM, Material Removal Rate (MRR) and Tool wear rate (TWR) are generally analyzed to assess its performance. For this, a perfect combination of input variables is required. In the present study, machining is done on Tool steel workpiece material using a pure copper electrode. The input parameters like Pulse-ON time, Pulse- OFF time, Current and Gap voltage are selected for experimentation and Taguchi method is employed for the DOE by considering 4 factors and 3 levels. A total of 27 experiments (L27 orthogonal array) have been designed with a possible combination of selected input parameters. The present work mainly focuses on development of an extensive mathematical model for correlating the input and output variables using a conventional regression analysis. The adequacy of proposed model was tested with the help of some collected data through experimentation using taguchi optimized DOE. The proposed linear multi-variable regression equation was found to be a best fitted model with 98% confidence levels.In non-traditional machining, electrical discharge machining (EDM) has tremendous potential on account of versatility of its applications and is successfully, commercially used in modern industries. EDM process is capable to machine geometrically complex, hard material components, tool steels, composites, super alloys, ceramics and carbides. In EDM, Material Removal Rate (MRR) and Tool wear rate (TWR) are generally analyzed to assess its performance. For this, a perfect combination of input variables is required. In the present study, machining is done on Tool steel workpiece material using a pure copper electrode. The input parameters like Pulse-ON time, Pulse- OFF time, Current and Gap voltage are selected for experimentation and Taguchi method is employed for the DOE by considering 4 factors and 3 levels. A total of 27 experiments (L27 orthogonal array) have been designed with a possible combination of selected input parameters. The present work mainly focuses on development of an extensive mathematical model for correlating the input and output variables using a conventional regression analysis. The adequacy of proposed model was tested with the help of some collected data through experimentation using taguchi optimized DOE. The proposed linear multi-variable regression equation was found to be a best fitted model with 98% confidence levels
Study of the effect of process parameters on the production of a non-simmetric low pressure die casting part
Low pressure die-casting is a "near net shape" foundry process that offers a good compromise between economical aspects, production rate and casting quality. Because of the constrained position of the gating system, the application of traditional LPDC process is generally limited to axis-symmetric or symmetric geometries. The aim of this work was to investigate the low pressure die-casting process in order to define the effect of various system settings on the production of a sound non-conventional cast component. The research was supported by the modelling of mould filling and casting solidification, in order to evaluate both the influence of process parameters and the reliability of the modelling software in the prediction of flow pattern and thermal history of casting as well as defects formation. The results were compared with those obtained on an experimental die, completely instrumented, to better understand the process, validate the calculation procedure and make more confident the use of this tool for complex parts. Metallographic analyses were also carried out to compare the quality of simulated and real castings, with particular reference to shrinkage and gas porosity
Pulsed Current Effect on the Hard Anodizing of an AlSi10Mg Aluminum Alloy Obtained via Additive Manufacturing
The hard anodizing treatments of cast Al-Si alloys are notoriously difficult. Indeed, their microstructural features hinder the growth of a uniform, compact, and defect-free anodic oxide. In this paper, AlSi10Mg samples, produced via Gravity Casting (GC) and Additive Manufacturing, i.e., Laser Powder Bed Fusion (L-PBF), were hard anodized in a sulfuric acid bath, in order to verify how the particular microstructure obtained via L-PBF affects the thickness, hardness, compactness, and defectiveness of the anodic oxide. Moreover, for the first time, Pulsed Direct Current (PDC) procedures were used to perform the hard anodizing treatments on additively manufactured AlSi10Mg alloy. Several combinations of temperature and electrical parameters, i.e., current density, frequency, and Duty Cycle, were tested. The anodized samples were characterized through optical microscopy analysis, Scanning Electron Microscopy (SEM) analysis, and accelerated corrosion tests, i.e., Potentiodynamic Polarization (POL) and Electrochemical Impedance Spectroscopy (EIS) measurements. The PDC procedures allowed improvement of the compromise between evenness, compactness, and defectiveness. Among the attempted PDC procedures, a specific combination of electrical parameters and temperature allowed the best results to be obtained, i.e., the highest hardness and the lowest volumetric expansion values without compromising the oxide quality rating and the corrosion resistance behavior. However, none of the attempted PCD strategies allowed the hardness values obtained on samples produced via GC to be reached
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