Electron spin resonance spectroscopy (ESR) and pulsed-gradient-spin-echo nuclear magnetic resonance (PGSE-NMR) measurements on poly(vinyl alcohol) (PVA) hydrogels reveal that nanostructure is not ...appreciably affected by the number of freezing–thawing cycles.
Macromolecular cross-linked ligands containing pyridyl pendant groups are characterized by a combination of inverse steric exclusion chromatography, ESR and NMR spectrometries in water and methanol. ...On the basis of the relevant results, methanol is seen to be clearly the best swelling agent and it is chosen as medium for CuII coordination.
Resumen Los procesos importantes relacionados con la dinámica del agua ocurren principalmente en la interfase suelo-atmósfera. La estructura de la cobertura de rastrojos de cultivos, tanto por ...cantidad como su distribución, tiene efecto sobre el microclima de la superficie del suelo y, en consecuencia, en el grado de conservación del agua. El objetivo de este trabajo fue evaluar algunos cambios en la interfase suelo-atmósfera y su impacto sobre el agua del suelo con diferentes estructuras de los residuos de cosecha. La experimentación se realizó en la Estación Experimental del Instituto Nacional de Tecnología Agropecuaria en Hilario Ascasubi, Villarino, Buenos Aires. Se evaluaron tres cereales invernales (trigo, centeno y avena) como antecesores del trigo entre junio del 2017 y diciembre de 2020, es decir, dos ciclos consecutivos de rotaciones agrícolas bianuales con cereales invernales. Se evaluó la estructura del rastrojo al final del barbecho a partir de la biomasa seca, su distribución por estratos y el índice de área del tallo. Además, se determinó la temperatura del suelo, velocidad relativa del viento y la dinámica del agua en el barbecho. Los cultivos de invierno antecesores y principalmente la disposición del rastrojo, presentaron diferencias en el aporte de biomasa y la estructura de la cobertura, asimismo se logró similar porcentaje de cobertura. Se observaron diferencias en el impacto de la disposición del rastrojo sobre la temperatura del suelo y velocidad del viento, pero no así por los antecesores. Esto modificó la eficiencia de barbecho, la humedad a la siembra del cultivo posterior y la evolución de la humedad del suelo hasta 13 días posteriores a un evento de precipitación. La disposición del rastrojo y los antecesores impactaron en los factores que componen la interfase suelo-atmósfera y, en consecuencia, en la dinámica del agua en el suelo.
Resumen La expansión de la agricultura y el aumento de la demanda de carne han incrementado las actividades ganaderas intensivas. Los residuos generados son problema ambiental, pero también son una ...fuente de nutrientes. La pelletización podría ser una alternativa para el uso masivo de estos materiales. El objetivo de este trabajo fue evaluar la aplicación de biofertilizantes pelletizados y en mezcla con fertilizantes químicos, en cultivos extensivos. Se prepararon macetas con suelo de textura franca y bajo nivel de fertilidad, para sembrar trigo (Triticum aestivum L.) en invernadero. El diseño experimental (n=102) incluyó 16 tratamientos y un testigo sin fertilización. Los fertilizantes se aplicaron en dos momentos diferentes: pre-siembra y siembra. Se cosechó la producción vegetativa, se contabilizaron el numero de macollos por planta y se secó el material en estufa para determinar materia seca. No se encontraron diferencias signifcativas entre fechas de aplicación de fertilizantes. Se encontraron diferencias significativas (p<0.0001) entre los tratamientos para ambas variables estudiadas. Los rendimientos fueron similares entre los tratamientos minerales y los orgánicos-minerales, esto sugiere que podrían economizarse fertilizantes químicos y reciclar grandes cantidades de N y P presentes en los residuos orgánicos, además de incoporar materia orgánica al suelo.
Staphylococcus aureus is the primary cause of skin and soft tissue infections. Its significant adaptability and the development of resistance are the main factors linked to its spread and the ...challenges in its treatment. Antimicrobial photodynamic therapy emerges as a promising alternative. This work aimed to characterize the antimicrobial photodynamic activity of Brazilian green propolis, along with the key bioactive compounds associated with this activity. Initially, a scanning spectrometry was conducted to assess the wavelengths with the potential to activate green propolis. Subsequently, reference strains of methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300) and vancomycin-intermediate Staphylococcus aureus (VISA ATCC 700699) were exposed to varying concentrations of green propolis: 1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg /mL and 100 µg/mL and were stimulated by blue, green or red LED light. Finally, high-performance liquid chromatography coupled with a diode array detector and tandem mass spectrometry techniques, along with classic molecular networking analysis, was performed to identify potential bioactive molecules with photodynamic activity. Brazilian green propolis exhibits a pronounced absorption peak and heightened photo-responsiveness when exposed to blue light within the range of 400 nm and 450 nm. This characteristic reveals noteworthy significant photodynamic activity against MRSA and VISA at concentrations from 5 µg/mL. Furthermore, the propolis comprises compounds like curcumin and other flavonoids sourced from flavone, which possess the potential for photodynamic activity and other antimicrobial functions. Consequently, Brazilian green propolis holds promise as an excellent bactericidal agent, displaying a synergistic antibacterial property enhanced by light-induced photodynamic effects.
Water and wind erosion are serious problems due to the loss of soil productivity. The coverage of soil, by means of cover crops or crops residues, is an effective tool to prevent wind and water ...erosion. The soil coverage could curb wind on the surface, avoid water runoff and reduce direct soil evaporation. Residue spatial distribution is the main factor to successful soil protection. The current work presents details of a prototype, design and validation as a measuring instrument to sense the height of vegetal crop residues based on a short-ranged laser distance sensor (LiDAR) and a computer numerical control (CNC) mechanism. The results obtained in this work showed a high level of confidence to estimate the height and composition of soil vegetal coverage.
Although the pharmacological therapy of ADHD has been widely studied, little has been done to compare the different therapeutic approaches (e.g., drug therapy vs. psychological treatments) and even ...less has been done to compare the outcome of the therapy between centers. This multicenter observational study aims to assess between-center variation in functional outcome of ADHD patients one year after the diagnosis, according to the treatment received. We used the Regional ADHD Registry data on 1429 patients enrolled in 16 ADHD centers in the 2011-2022 period. To evaluate the effectiveness of the therapy we used a generalized linear mixed model with the center as the random effect, including patient condition at diagnosis and center characteristics, weighting by the inverse of the propensity score of the treatment received by the patient. Between-center variation was expressed as the relative difference in odds-ratios between the observed and the expected number of patients whose condition improved, using the Clinical Global Impressions-Improvement Scale (CGI-I), and the relative 95% CI. Patients who received combined treatment were significantly more likely to improve compared to other treatment groups (65.5% vs 54.4% for methylphenidate alone, 53.4% for psychological treatment alone, or 40.5% for no therapy). Adjusted for patients and center characteristics, the log-odds ratio ranged from 0.85 (0.29-1.55 95% CI) to - 0.64 (- 1.17-- 0.18 95% CI). The mean expected probability of improvement after one year of therapy for an average patient with ADHD for each center was 47.7% in a center at the 25th percentile and 61.2% in a center at the 75th percentile of the outcome distribution after adjustments. The wide between-center variation in patient functional improvement one year after the diagnosis of ADHD could be largely explained by center-specific therapeutic approaches or attitudes. More careful and stringent work is needed to reduce differences in responses between centers, as could formal and periodic audit programs within and between centers.
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