B lymphocytes are recognized for their crucial role in the adaptive immunity since they represent the only leukocyte lineage capable of differentiating into Ab‐secreting cells. However, it has been ...demonstrated that these lymphocytes can exert several Ab‐independent functions, including engulfing and processing Ags for presentation to T cells, secreting soluble mediators, providing co‐stimulatory signals, and even participating in lymphoid tissues development. Beyond that, several reports claiming the existence of multiple B cell subsets contributing directly to innate immune responses have appeared. These “innate‐like” B lymphocytes, whose phenotype, development pathways, tissue distribution, and functions are in most cases notoriously different from those of conventional B cells, are crucial to early protective responses against pathogens by exerting “crossover” defensive strategies that blur the established boundaries of innate and adaptive branches of immunity. Examples of these mechanisms include the rapid secretion of the polyspecific natural Abs, increased susceptibility to innate receptors‐mediated activation, cytokine secretion, downstream priming of other innate cells, usage of specific variable immunoglobulin gene‐segments, and other features. As these new insights emerge, it is becoming preponderant to redefine the functionality of B cells beyond their classical adaptive‐immune tasks.
Beyond conventional populations, B cell compartment comprises several subsets developing “innate‐like” functions, implicated in early protection against pathogens mediated by different mechanisms besides antibody secretion.
CoCrMo alloys are used in a wide range of applications because of their acceptable fatigue strength and corrosion resistance. However, CoCrMo-based components exhibit a deleterious effect of wear. ...For this reason, surface modification through ceramic coatings has become in a useful alternative to improve mechanical resistance. The main aim of the present study was to investigate the tribological behavior of a system of diffusional boride layers formed on the substrate of CoCrMo alloy. For this purpose, different boron diffusion heat treatment parameters were performed: 1223, 1248 and 1273 K by 6, 8 and 10 h, respectively. Surfaces were characterized using scanning electron microscopy (SEM), surface roughness measurement, micro-hardness testing, and X-ray diffraction. The tribological response was studied by means of ball on disc tribometer under dry-sliding conditions tracking their friction coefficient, mass loss, wear rate and surface damage by stereoscopy and SEM. Boride coating at 1223 K by 6 h showed the better wear resistance, increased it 6 times relative to the wear resistance obtained for the CoCr alloy untreated sample.
•CoCr borided sample at 1223 K – 6 h increased 6 times the wear resistance in comparison with the CoCr untreated sample.•The wear resistant borided layer was correlated with temperature and time parameters of boronizing process.•The maximum hardness value achieved on the borided surface was 5 times higher than the hardness of the substrate.•The main wear mechanism was severe abrasion for the untreated sample and surface fatigue for the borided samples.
In this study the mechanical behavior of FeB and Fe2B layers formed at the surface of AISI D2 steels was estimated by the Berkovich nanoindentation technique. The boriding of AISI D2 steels was ...developed by the powder-pack method at temperatures of 1223, 1273 and 1323K with exposure times of 3–7h for each temperature. The mechanical characterization was performed to determine the effect of the set of experimental parameters of the boriding process with three experimental procedures: first, nanoindentation was performed along the depth of the surface layers at a constant load of 250mN to determine the hardness gradient and the state of the thermal residual stresses in the boride layers; then, loads in the range of 10 to 300mN were applied to the “pure” zone of the FeB layer at a distance of 10μm from the surface, and in the “pure” zone of the Fe2B layer (40μm), respectively. Finally, the fracture toughness, compressive residual stresses, and brittleness of the boride layers were evaluated using the length of the cracks that originated from the corners of the Berkovich nanoindentation site after the application of loads ranging from 300 to 500mN.
For a constant load of 250mN, the results showed that the state of thermal residual stresses and the hardness of both the FeB and Fe2B layers were a function of the temperature and exposure time of the process. Moreover, the presence of the indentation size effect (ISE) in the FeB and Fe2B layers was verified in the range of applied loads (10–300mN), in which the apparent or real hardness was estimated by the elastic recovery (ER) model according to the boriding experimental parameters. Finally, the estimated values of the fracture resistance and brittleness of the boride layers fell within the range of 1.48–3.02MPam and 2.01–4.65MPam, with the presence of compressive stresses in the range of 428 to 1604MPa for the FeB and Fe2B layers, respectively.
► Mechanical properties of the FeB and Fe2B layers were evaluated by nanoindentation. ► The thermal residual stresses across the boride layers were compressive. ► The presence of the indentation size effect was verified in both FeB and Fe2B layers. ► The FeB layer showed low fracture resistance with high brittleness.
Currently furfural production has been the subject of increased interest because it is a biobased chemical able to compete with fossil-based chemicals. Furfural is characterized by flammability, ...explosion, and toxicity properties. Improper handling and process design can lead to catastrophic accidents. Hence it is of most importance to use inherent safety concepts during the design stage. This work is the first to present several new downstream separation processes for furfural purification, which are designed using an optimization approach that simultaneously considers safety criteria in addition to the total annual cost and the eco-indicator 99. The proposed schemes include thermally coupled configuration, thermodynamic equivalent configuration, dividing-wall column, and a heat integrated configuration. These are compared with the traditional separation process of furfural known as the Quaker Oats Process. The results show that because of a large amount of water present in the feed, similar values are obtained for total annual cost and eco-indicator 99 in all cases. Moreover, the topology of the processes has an important role in the safety criteria. The thermodynamic equivalent configuration resulted as the safest alternative with a 40% reduction of the inherent risk with respect to the Quaker Oats Process, and thus it is the safest option to purify furfural.
•Al7075–graphite composites were synthesized by mechanical alloying and hot extrusion.•Effects of graphite content and milling time on the mechanical and wear properties of fabricated composites were ...analyzed.•Microstructure and worn surfaces of samples were studied by transmission and scanning electron microscope.•The friction coefficient, wear rate and debris thickness of fabricated composite were investigated.
Aluminum matrix composites (AMCs) are candidate materials for aerospace and automotive industry owing to their large elastic modulus, improved strength and low wear rate. A simple method for fabrication of Al7075–graphite composites produced by mechanical alloying (MI) and hot extrusion is described in this paper. Effects of milling time (0–10h) and graphite concentration (0–1.5wt.%) on friction, hardness and wear resistance of the AMC were investigated. Wear resistance was determined by the pin-on-disk wear method using 20 and 40N normal loads at a 0.367m/s sliding velocity. The worn surfaces were examined by scanning electron microscopy (SEM) to identify distinct topographical features for elucidation of the prevailing wear mechanisms. Experimental results indicated considerable improvement in AMC hardness and wear resistance by adding 1.5% G (wt.) and 10h of milling, showing homogenous distribution of the reinforcement particles in the Al-base metal-matrix composite. It was found that abrasion is the dominant wear mechanism in all extruded composites, whilst a combination of adhesion and delamination seems to be the governing mechanism for the 7075 aluminum alloy.
Nowadays, there is an increasing concern over the presence of contaminants in the aquatic environment, where they can be introduced from wastewater after their incomplete removal in the treatment ...plants. In this work, degradation of selected emerging pollutants in the aqueous and solid phases of sewage sludge has been investigated after anaerobic digestion using two different digesters: mesophilic and thermophilic. Initially, sludge samples were screened by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) for identification of emerging contaminants in the samples. In a second step, a target quantitative method based on LC coupled to tandem MS was applied for selected pollutants identified in the previous screening. The behaviour of the compounds under anaerobic conditions was studied estimating the degradation efficiency and distribution of compounds between both sludge phases. Irbesartan and benzoylecgonine seemed to be notably degraded in both phases of the sludge. Venlafaxine showed a significant concentration decrease in the aqueous phase in parallel to an increase in the solid phase. The majority of the compounds showed an increase of their concentrations in both phases after the digestion. Concentrations in the solid phase were commonly higher than in the aqueous for most contaminants, indicating that they were preferentially adsorbed onto the solid particles.
Display omitted
•Anaerobic digestion of 13 emerging pollutants was studied in sewage sludge.•Mesophilic and thermophilic anaerobic bacteria were tested.•Concentrations of contaminants were evaluated in aqueous and solid phases of the sludge.•Irbesartan and benzoylecgonine seemed to be degraded in both phases of the sludge.•Concentrations in solid phase were commonly higher than in aqueous phase.
The contribution of B cells in COVID‐19 pathogenesis, beyond the production of specific antibodies against SARS‐CoV‐2, is still not well understood. Since one of their most relevant functional roles ...includes their immune‐suppressive mechanisms, we decided to evaluate one of the most recognized human B regulatory subpopulations: the IL‐10+ B10 cells, during COVID‐19 onset. After stimulation of PBMCs for IL‐10 induction, we employed multiparametric flow cytometry to determine B10 frequencies in severe and critical COVID‐19 patients and then correlated those with clinical and laboratory parameters. Compared with healthy individuals, we detected a significant reduction in the B10 subset in both patient groups, which correlates with some inflammatory parameters that define the disease severity. This evidence suggests an aberrant role of B10 cells in immune responses against SARS‐CoV‐2 that needs to be further explained.
Graphical
The B regulatory subset B10 (CD24hiCD27+IL‐10+) was found depleted during severe/critical COVID‐19 acute disease, negatively correlating with inflammatory parameters.
Mexico is the center of origin of the species popularly known as toronjil or lemon balm (Agastache mexicana Linton & Epling). Two subspecies have been identified and are commonly called purple or red ...(Agastache mexicana Linton & Epling subspecies. mexicana) and white (Agastache mexicana subspecies xolocotziana Bye, E.L. Linares & Ramamoorthy). Plants from these subspecies differ in the size and form of inflorescence and leaves. They also possess differences in their chemical compositions, including volatile compounds. Traditional Mexican medicine employs both subspecies. A. mexicana exhibits a broad range of pharmacological properties, such as anti-inflammatory, anxiolytic, and antioxidant. A systematic vision of these plant’s properties is discussed in this review, exposing its significant potential as a source of valuable bioactive compounds. Furthermore, this review provides an understanding of the elements that make up the species’ holistic system to benefit from lemon balm sustainably.
Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism. Folate deficiency has been related to several conditions, including neural tube defects (NTDs) and cardiovascular ...diseases. Hence, MTHFR genetic variants have been studied worldwide, particularly the C677T and A1298C. We genotyped the C677T and A1298C MTHFR polymorphisms in Mexican Amerindians (MAs), from the largest sample included in a genetic study (n = 2026, from 62 ethnic groups), and in a geographically-matched Mexican Mestizo population (MEZ, n = 638). The 677T allele was most frequent in Mexican individuals, particularly in MAs. The frequency of this allele in both MAs and MEZs was clearly enriched in the South region of the country, followed by the Central East and South East regions. In contrast, the frequency of the 1298C risk allele in Mexicans was one of the lowest in the world. Both in MAs and MEZs the variants 677T and 1298C displayed opposite allele frequency gradients from southern to northern Mexico. Our findings suggest that in Mestizos the 677T allele was derived from Amerindians while the 1298C allele was a European contribution. Some subgroups showed an allele frequency distribution that highlighted their genetic diversity. Notably, the distribution of the frequency of the 677T allele was consistent with that of the high incidence of NTDs reported in MEZ.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
