Evaluation of the degradation of the graphene-polypropylene composites of masks in harsh working conditions

The recent COVID-19 outbreak has led health authorities to recommend at least the use of surgical masks, most preferably respirators (FFP2 or KN95), to prevent the spread of the virus. Non-woven fabrics have been chosen as the best option to manufacture the face masks, due to their filtration efficiency, low cost, and versatility. Modifying the mask filters with graphene has been of great interest due to its potential use as antibacterial and virucidal properties. Indeed, some companies have commercialized face masks in which graphene is coated and/or embedded. However, the Canadian sanitary authorities advised against using the Shandong Shengquan New Materials Co. graphene masks because of the possibility of pulmonary damage produced by graphene inhalation. Thus, we have analyzed the stability of the graphene filter of these masks and compared it with two other commercially available graphene mask filters, evaluating the morphological and spectroscopical change of the fibers, as well as the particles released during the endurance tests. Our work introduces the necessary tools and methodology to evaluate the potential degradation of face masks under extreme working conditions. These methods complement the present standard tests ensuring the security of the new filters based on composites or nanomaterials.

Steroids and mortality in non-critically ill COVID-19 patients: a propensity score-weighted study in a Chilean cohort

Objectives

The aim of this study was to evaluate the impact on 30-day mortality of early use of corticosteroids in COVID-19 patients with supplementary oxygen requirements and without invasive mechanical ventilation at the initiation of therapy.

Methods

All patients hospitalized with COVID-19 between April 15 and July 15, 2020, and requiring supplementary oxygen, were prospectively included in a database. Patients who died or required intubation within the first 48 hours were excluded. Patients who received corticosteroids within the first 5 days of hospitalization and at least 24 hours prior to intubation were allocated to the ‘early corticosteroids’ group. To compare both populations and adjust for non-random treatment assignment bias, a weight-adjusted propensity score model was used.

Results

In total, 571 patients met the inclusion criteria, 520 had sufficient information for the analysis. Of these, 233 received early corticosteroids and 287 did not. Analysis showed a reduction of 8.5% (p = 0.038) in 30-day mortality in the early corticosteroid group. The reduction in mortality was not significant when patients with corticosteroid initiation between day 5 and day 8 of hospitalization were included.

Conclusion

Early corticosteroid use reduced mortality in patients with pneumonia due to COVID-19, who required supplementary oxygen but not initial invasive mechanical ventilation.

A bioinspired metal-organic approach to cross-linked functional 3D nanofibrous hydro- and aero-gels with effective mixture separation of nucleobases by molecular recognition

The direct reaction between Cu(CH3COO)2 and uracil-1-acetic acid in water gives rise to the formation of a hydrogel consisting of entangled nanometric ribbons of a crystalline antiferromagnetic 1D Cu(ii) coordination polymer (CP) decorated with biocompatible uracil nucleobases. This hydrogel is the precursor for the preparation of a meso/macroporous ultralight aerogel that shows a remarkable Young's modulus. As a proof-of-concept of the molecular recognition capability of the terminal uracil moieties anchored at Cu(ii) CP chains, this material has been tested as the selective stationary phase for the separation of nucleobase derivatives in HPLC columns.

Covalent organic framework nanosheets: preparation, properties and applications

Covalent organic frameworks are crystalline porous materials with 2- or 3-dimensional structures designed modularly from their molecular precursors. Using bottom-up or top-down strategies, single- or few-layer materials can be obtained from them.

Recent advances of the OIV working group on oenological tannins in the study of the functionalities of oenological tannins

This communication actualizes the status of the research of the OIV working group on oenological tannins with the purpose of deepening the knowledge of the mechanisms and functionalities of oenological tannins in winemaking. The obtained results confirm that oenological tannins really exert an effect as copigments and that they really protect the wine color against the negative effect of the enzyme laccase present in grapes affected by the infection of Botrytis cinerea.

Reducción del contenido de alcohol y pH de vinos tintos Pinot noir y Tannat empleando uvas con diferentes niveles de maduración

El objetivo de esta investigación fue determinar la efectividad de la mezcla de mostos de uvas con diferente grado de maduración para la obtención de vinos Pinot noir y Tannat con menor contenido de alcohol y pH. En envero, se extrajo mosto de uvas inmaduras que se conservó a 4 ∘C hasta su uso. En madurez tecnológica, las uvas cosechadas fueron despalilladas, estrujadas y distribuidas en seis recipientes. Tres fueron vinificados de forma tradicional, mientras que en los otros tres se realizó una sustitución de 3 L del mosto de uva madura por 3 L del mosto de uvas inmaduras. Ambos tratamientos realizaron una maceración fermentativa de 7 días. Se determinó la composición básica del vino, color, concentración de fenoles totales, antocianos, catequinas y proantocianidinas a los dos meses del descube. La sustitución de mosto permitió elaborar vinos Pinot noir y Tannat con menor contenido de alcohol y pH, sin reducir las concentraciones de polifenoles totales, catequinas o antocianos. El efecto sobre la concentración de proantocianidinas fue variable de acuerdo con el cultivar y año de vendimia. Los vinos Tannat reducidos en alcohol presentaron mayor intensidad de color, menor tono e igual cromaticidad que los vinos testigos.

Influence of supplementation with two specific inactivated dry yeast and grape-skin extract on the color and composition of red wine

Wines from grapes of Cabernet Sauvignon of the AOC Tarragona were elaborated with supplementation or not of two specific inactivated dry yeasts (Optired® and Optimum Red®; Lallemand Inc.) or with an experimental grape-skin extract. All the wines treated were significantly less astringent than the control wine because both inactivated dry yeast and the skin extract released polysaccharides which probably inhibit interactions between salivary proteins and tannins, and because their presence decrease the proportion of seed tannins and increase the proportion of skin tannins in the final wines.

Evaluación de la composición y calidad del color de vinos tintos Tannat elaborados por maceración pre-fermentativa en caliente

Durante la vendimia 2016 se elaboraron vinos tintos Tannat por maceración pre-fermentativa en caliente (una hora de calentamiento a 60–70 ∘C seguido de una maceración fermentativa de 7 días) y maceración tradicional (maceración fermentativa de 7 días) con el objetivo de evaluar su concentración en compuestos fenólicos y color durante la conservación. Las vinificaciones se realizaron por triplicado en recipientes de 10 litros de capacidad. Se determinó la composición básica del vino, color, concentración de fenoles totales, antocianos, catequinas, proantocianidinas y los índices de ionización, copigmentados y PVPP. Los vinos con maceración pre-fermentativa en caliente presentaron mayor concentración de antocianos y taninos, mayor porcentaje de antocianos ionizados, co-pigmentados y condensados. Adicionalmente, presentaron mayor proporcion de delfinidina, petunidina y peonidina al descube. El calentamiento degrada las enzimas polifenoloxidasas por lo que estas formas antociánicas pudieron haber sido preservadas de la oxidación. Las concentraciones de las diferentes formas antociánicas disminuyeron durante la conservación de los vinos de ambos tratamientos, sin observarse diferencias en el perfil antocianico después de dos años. Los vinos elaborados por maceración pre-fermentativa en caliente presentaron mayor intensidad colorante durante todo el período de evaluación sugiriendo una mayor estabilidad del color.

New insight about the functionality of oenological tannins; Main results of the working group on oenological tannins

This communication synthetize all the results obtained by the OIV working group on oenological tannins to the current date. The obtained results confirm that oenological tannins really exert a protection effect against grape juice and wine oxidation because they have antioxidant activity, they consume directly oxygen and they exert an inhibitory effect on the laccase activity. Moreover, oenological tannins also exert a copigmentation effect which can improve and protect de color of red wines.

Influence of the micro-oxygenation dose and supplementation with oak staves of different potential of ellagitannin release on wine color and composition

Aliquots of a wine of Merlot were micro-oxygenated at two doses of oxygen (2.5 and 5.0 mg of O2/L.month) in the presence or not of oak staves of different potential ellagitannin release (PER) for three months. In general, micro-oxygenation increased the color intensity and stability probably because favor the formation of new pigments. The presence of staves increased the total phenolic index and the ellagitannin concentration, and this effect was higher when greater was the PER of the staves. Finally, the dose of microoxygenation only affects the concentration of total furanic compounds whereas the PER of the staves seems to determine the concentration of furanic compounds, volatile phenols and β-methyl-γ-octolactones.

Multistimuli Response Micro- and Nanolayers of a Coordination Polymer Based on Cu2 I2 Chains Linked by 2-Aminopyrazine

A nonporous laminar coordination polymer of formula [Cu2 I2 (2-aminopyrazine)]n is prepared by direct reaction between CuI and 2-aminopyrazine, two industrially available building blocks. The fine tuning of the reaction conditions allows obtaining [Cu2 I2 (2-aminopyrazine)]n in micrometric and nanometric sizes with same structure and composition. Interestingly, both materials show similar reversible thermo- and pressure-luminescent response as well as reversible electrical response to volatile organic solvents such as acetic acid. X-ray diffraction studies under different conditions, temperatures and pressures, in combination with theoretical calculations allow rationalizing the physical properties of this compound and its changes under physical stimuli. Thus, the emission dramatically increases when lowering the temperature, while an enhancement of the pressure produces a decrease in the emission intensity. These observations emerge as a direct consequence of the high structural flexibility of the Cu2 I2 chains which undergo a contraction in CuCu distances as far as temperature decreases or pressure increases. However, the strong structural changes observed under high pressure lead to an unexpected effect that produces a less effective CuCu orbital overlapping that justifies the decrease in the intensity emission. This work shows the high potential of materials based on Cu2 I2 chains for new applications.

Homogeneous Diffusion Solid Model as a Realistic Approach to Describe Adsorption onto Materials with Different Geometries

In this work, the adsorption kinetics of p-nitrophenol (PNP) onto several commercial activated carbons (ACs) with different textural and geometrical characteristics was studied. For this aim, a homogeneous diffusion solid model (HDSM) was used, which does take the adsorbent shape into account. The HDSM was solved by means of the finite element method (FEM) using the commercial software COMSOL. The different kinetic patterns observed in the experiments carried out can be described by the developed model, which shows that the sharp drop of adsorption rate observed in some samples is caused by the formation of a concentration wave. The model allows one to visualize the changes in concentration taking place in both liquid and solid phases, which enables us to link the kinetic behaviour with the main features of the carbon samples.

Influence of the Presence of the Lees during Oak Ageing on Colour and Phenolic Compounds Composition of Red Wine

Oak ageing of red wine in the presence of lees is currently a procedure that is being introduced in most wineries. This work analysed the influence of this technique on colour and phenolic compounds of two red wines, one with a low ageing potential (low anthocyanin and proanthocyanidin concentration) and the other one with a high ageing potential (high anthocyanin and proanthocyanidin concentration). Wines, after six months of ageing in new American oak barrels, were analysed and tasted by expert panellists. In general terms, ageing in the presence of lees presented the disadvantage of producing wines with a slightly less intense colour and with lower proanthocyanidin concentration. However, the advantages were that wines presented a colour slightly less evolved towards yellowish nuances, a non-negligible diminution of their astringency and an increase in the mouthfeel perception.

MasterChem: cooking 2D-polymers

This review summarized the current state-of-the-art in the field of synthetic 2D-polymers showing different routes to prepare these polymers and their physical properties.

Reversible stimulus-responsive Cu(i) iodide pyridine coordination polymer

A coordination polymer based on CuI double chains with substituted pyrimidine is a dynamic and reversible material very sensible to both physical and chemical stimuli.

Reversible recrystallization process of copper and silver thioacetamide–halide coordination polymers and their basic building blocks

Three-dimensional [CuX(TAA)]_n (X = Br (1), I (2)) and bi-dimensional [AgX(TAA)]_n (X = Cl (3), Br (4)) coordination polymers have been isolated by the direct synthesis from copper(i) and silver(i) halides and thioacetamide (TAA).

Effect of two different treatments for reducing grape yield in Vitis vinifera cv Syrah on wine composition and quality: berry thinning versus cluster thinning

The influence of two treatments for reducing grape yield, cluster thinning and berry thinning, on red wine composition and quality were studied in a Vitis vinifera cv Syrah vineyard in AOC Penedès (Spain). Cluster thinning reduced grape yield per vine by around 40% whereas berry thinning only reduced it by around 20%. Cluster thinning grapes had higher soluble solids content than control grapes, and their resultant wines have greater anthocyanin and polysaccharide concentrations than the control wine. Wine obtained from berry thinning grapes had a higher total phenolic index, greater flavonol, proanthocyanidin, and polysaccharide concentrations, and lower titratable acidity than the control wine. Wines obtained from both treatments were sufficiently different from the control wine to be significantly distinguished by a trained panel in a triangular test. Even though both treatments seem to be effective at improving the quality of wine, berry thinning has the advantage because it has less impact on crop yield reduction.

Elevation of viral load by PCR and use of plasma preparation tubes for quantification of human immunodeficiency virus type 1

HIV-1 viral load testing from 51 patients was compared in plasma samples simultaneously processed and stored in primary Vacutainer plasma preparation tubes (PPTs) and PPT sample aliquots transferred in secondary tubes before freezing, using RT-PCR quantification with an ultrasensitive method (the Roche AMPLICOR HIV-1 MONITOR). We concluded that freezing the primary sample in the PPT collection tube can artificially elevate the HIV-1 viral load. We therefore store samples as frozen aliquots in a second tube.

Adsorption of p-nitrophenol on activated carbon fixed-bed

Carbon fixed-beds are usually used to remove organic contaminants. Adsorption in a carbon filter is a dynamic, non-steady process which is not yet completely understood. The objective of this paper is to establish a methodology to simplify the study of this process based on the wave theory, rapid small-scale column test and experimental design/surface response analysis. The constant pattern wave hypothesis was confirmed by the experimental data. The influence of the inlet concentration of p-nitrophenol and the flow rate on dynamic adsorption was studied at 20 degrees C following a central composite design using a second-order model. Both parameters have an important influence on the response variables studied. The methodology used is a useful tool for studying the dynamic process and shows interactions that are difficult to verify by the classical step-by-step method.

Influence of ethanol concentration on the extraction of color and phenolic compounds from the skin and seeds of Tempranillo grapes at different stages of ripening

The aim of this paper is to study how grape ripeness and ethanol concentration affect the extraction of color and phenolic compounds from skins and seeds during the maceration/fermentation process. Simulated maceration assays were carried out with the grapes at three stages of berry development (vitis vinifera cv. Tempranillo) and different percentages of ethanol in the maceration media. Both ripeness and ethanol content have a considerable effect on the extraction of color and phenolic compounds. Of these two factors, ripeness increases the extractability most. The presence of ethanol in the medium facilitates anthocyanin and especially proanthocyanidin extraction, but it also decreases copigmentation phenomena, which can decrease the color intensity. The higher the ethanol concentration is in the maceration media, the higher the astringency of proanthocyanidins.

[Clinical features of cerebral toxoplasmosis in Cuban patients with AIDS]

INTRODUCTION

Neurotoxoplasmosis (NTX) is one of the commonest opportunist infections in patients infected by the human immunodeficiency virus. It presents with a variety of clinical features in the immunocompromised patient.

PATIENTS AND METHODS

We made a horizontal retrospective descriptive study of 88 patients with a diagnosis of NTX treated in the Pedro Kour Institute during a three years period. Our aim was to find which were the most common forms of clinical presentation in our setting and to evaluate the use of paraclinical examinations in reaching the presumptive diagnosis. The patients had clinical examinations, CSF studies, detection of indirect immunofluorescence titres (IFI) for Toxoplasma, imaging studies (CAT) and lymphocyte counts.

RESULTS

The commonest symptoms were: headache in 79%, fever in 55.68%, motor defect in 44.31% and disorders of consciousness in 29.54% of the patients. The IFI titres were negative in 31.54% of the patients, between 1/16 and 1/32 in 38.34% and between 1/64 and 1/1,024 in only 30.07% of cases. The T CD4+ lymphocyte count was less than 200 cells in 66.7% of the patients; 72% of imaging studies showed typical lesions, in association with other disorders in 38% of the cases (lymphomas, cryptococcosis, tuberculous meningoencephalitis and cytomegalovirus encephalitis).

CONCLUSIONS

NTX in a patient with AIDS often presents in our setting with headache and fever, motor deficit and alterations of consciousness. The diagnosis should be confirmed by immunological or imaging studies since in this disease serology and CSF studies are less specific.

Molecular analysis of yeast population dynamics: effect of sulphur dioxide and inoculum on must fermentation

The effects of sulphur dioxide and a commercial starter inoculum on yeast population dynamics have been analysed by a molecular approach. Yeast identification from fermenting Carinyena grape musts was performed by RFLP's of mtDNA and rRNA-coding DNA. As expected, the use of a commercial inoculum speeded up the start of fermentation, while SO2 addition limited the development of non-Saccharomyces species. However, this effect was also observed with yeast inoculation. Further analysis of population dynamics could lead to a recommendation for the reduction of the dosage of SO2 by the addition of appropriate inoculum of yeasts in the must. Furthermore, the timing of inoculum addition could be modified to allow a proper contribution of non-Saccharomyces species. Molecular biology analysis of population dynamics could provide a tool to efficiently reduce the dosage of SO2 and adjust the timing of inoculum addition.