Laccase immobilization on bacterial nanocellulose membranes: antimicrobial, kinetic and stability properties

This work studied the physical immobilization of a commercial laccase on bacterial nanocellulose (BNC) aiming to identify the laccase antibacterial properties suitable for wound dressings. Physico-chemical analysis demonstrates that the BNC structure is manly formed by pure crystalline I cellulose. The pH optimum and activation energy of free laccase depends on the substrate employed corresponding to pH 6, 7, 3 and 57, 22, 48 kJ mol1 for 2,6-dimethylphenol (DMP), catechol and 2,2 -azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. The Michaelis-Menten constant (Km) value for the immobilized laccase (0.77 mM) was found to be almost double of that of the free enzyme (0.42 mM). However, the specific activities of immobilized and free laccase are similar suggesting that the cage-like structure of BNC allows entrapped laccase to maintain some flexibility and favour substrate accessibility. The results clearly show the antimicrobial effect of laccase in Gram-positive (92%) and Gram-negative (26%) bacteria and cytotoxicity acceptable for wound dressing applications.Andrea Zille (C2011-UMINHO-2C2T-01) acknowledges FCT funding from Programa Compromisso para a Ciência 2008, Portugal, FEDER funding on the Programa Operacional Factores de Competitividade - COMPETE and by national funds through FCT – Foundation for Science and Technology within the scope of the project POCI-01-0145-FEDER-007136 and UID/CTM/00264. Jorge Padrão and João P. Silva acknowledge Portuguese Foundation for Science and Technology (FCT) grants SFRH/BD/64901/2009 and SFRH/BPD/64958/2009 respectively. The authors Jorge Padrão, JoãoP. Silva and Fernando Dourado would like to thank the FCT StrategicProject PEst-OE/EQB/LA0023/2013, also to the Project “BioHealth −Biotechnology and Bioengineering approaches to improve healthquality”, Ref. NORTE-07-0124-FEDER-000027, co-funded by thePrograma Operacional Regional do Norte (ON.2-O Novo Norte),QREN, FEDER, and finnally to RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462)

Preparation and characterization of gelatin/arabic gum microcapsules containing methyl salicylate deposited onto a cotton fabric

A técnica de microencapsulação vem chamando a atenção de diversos pesquisadores nos últimos anos por ser uma técnica eficiente na captura física de substâncias ativas que apresentam sensibilidade a agentes externos, o que possibilita obter uma liberação sustentada destas substâncias. Dentro deste contexto, a tendência pela mistura de polímeros tem se mostrado eficaz e promissora devido as altas cargas alcançáveis de microencapsulação, técnica esta denominada por coacervação complexa. Parâmetros da interação entre os biopolímeros Gelatina e a Goma Arábica são amplamente estudados para a formação da parede das microcápsulas, sendo o pH o parâmetro mais crítico do processo. A tecnologia da microencapsulação tem sido aplicada em diferentes segmentos industriais, dentre eles na indústria têxtil, que tem se destacado para desenvolver acabamentos e propriedades diferenciadas. Com base nisso, o presente trabalho avaliou os efeitos da complexação do Salicilato de Metila, utilizando como materiais de parede a gelatina e a goma arábica e a impregnação do acabamento em malha 100% algodão.COMPETE -Programa Operacional Temático Factores de Competitividade(POCI-01-0145-FEDER-007136)info:eu-repo/semantics/publishedVersio

Sex Differences in Desiccation Tolerance Varies by Colony in the Mesic Liverwort \u3ci\u3ePlagiochila porelloides\u3c/i\u3e

Water scarcity, a common stress factor, negatively impacts plant performance. Strategies to cope with it, such as desiccation tolerance, are becoming increasingly important to investigate. However, phenomena, such as intraspecific variation in stress responses have not received much attention. Knowledge of this variability and the environmental drivers can be leveraged to further investigate the mechanisms of desiccation tolerance. Here we tested for variation in desiccation tolerance in Plagiochila porelloides among colonies and sexes within the same riparian zone. Field-collected dehardened plants were subjected to a desiccation event, under controlled conditions and then rehydrated. Plant water status, photosynthetic rates, net carbon gain, and efficiency of photosystem II (PSII) were assayed to evaluate tissue desiccation, basic metabolic processes and plant recovery. To establish a linkage between plant response and environmental factors, field light conditions were measured. We detected intraspecific variation, where a more exposed colony (high percentage of open sky, large temporal range of light quantity, and high red/far-red ratio) showed sex differences in desiccation tolerance and recovery. Overall, PSII recovery occurred by 72 h after rehydration, with a positive carbon gain occurring by day 30. This within species variation suggests plastic or genetic effects, and likely association with light conditions

Antimicrobial enzyme immobilization in bacterial cellulose

This work studied the physical immobilization of laccase on bacterial nanocellulose (BNC) aiming to identify the enzyme antibacterial properties suitable for wound dressings. The pH optimum and activation energy of free laccase depends on the substrate employed. The Michaelis-Menten constant for the immobilized laccase was found to be almost double of that of the free enzyme. However, the specific activities of immobilized and free laccase are similar suggesting that entrapped laccase on BNC maintain some flexibility and favour substrate accessibility. The results clearly show the antimicrobial effect of laccase and cytotoxicity acceptable for wound dressing applications.A. Zille acknowledges funding from FCT within the scope of the project POCI-01-0145- FEDER-007136 and UID/CTM/00264.info:eu-repo/semantics/publishedVersio

Acute respiratory viral infections in pediatric cancer patients undergoing chemotherapy

AbstractObjectiveTo estimate the prevalence of infection by respiratory viruses in pediatric patients with cancer and acute respiratory infection (ARI) and/or fever.MethodsCross-sectional study, from January 2011 to December 2012. The secretions of nasopharyngeal aspirates were analyzed in children younger than 21 years with acute respiratory infections. Patients were treated at the Grupo em Defesa da Criança Com Câncer (Grendacc) and University Hospital (HU), Jundiaí, SP. The rapid test was used for detection of influenza virus (Kit Biotrin, Inc., Ireland), and real-time multiplex polymerase chain reaction (FTD, Respiratory pathogens, multiplex Fast Trade Kit, Malta) for detection of influenza virus (H1N1, B), rhinovirus, parainfluenza virus, adenovirus, respiratory syncytial virus, human parechovirus, bocavirus, metapneumovirus, and human coronavirus. The prevalence of viral infection was estimated and association tests were used (χ2 or Fisher's exact test).Results104 samples of nasopharyngeal aspirate and blood were analyzed. The median age was 12±5.2 years, 51% males, 68% whites, 32% had repeated ARIs, 32% prior antibiotic use, 19.8% cough, and 8% contact with ARIs. A total of 94.3% were in good general status. Acute lymphocytic leukemia (42.3%) was the most prevalent neoplasia. Respiratory viruses were detected in 50 samples: rhinoviruses (23.1%), respiratory syncytial virus AB (8.7%), and coronavirus (6.8%). Codetection occurred in 19% of cases with 2 viruses and in 3% of those with 3 viruses, and was more frequent between rhinovirus and coronavirus 43. Fever in neutropenic patients was observed in 13%, of which four (30.7) were positive for viruses. There were no deaths.ConclusionsThe prevalence of respiratory viruses was relevant in the infectious episode, with no increase in morbidity and mortality. Viral co-detection was frequent in patients with cancer and ARIs

Asteroseismology of the Hyades with K2: first detection of main-sequence solar-like oscillations in an open cluster

The Hyades open cluster was targeted during Campaign 4 (C4) of the NASA K2 mission, and short-cadence data were collected on a number of cool main-sequence stars. Here, we report results on two F-type stars that show detectable oscillations of a quality that allows asteroseismic analyses to be performed. These are the first ever detections of solar-like oscillations in main-sequence stars in an open cluster.Comment: 12 pages, 8 figures, 2 tables; accepted for publication in MNRA

The Benefits of High-Intensity Interval Training on Cognition and Blood Pressure in Older Adults With Hypertension and Subjective Cognitive Decline: Results From the Heart & Mind Study

Background: The impact of exercise on cognition in older adults with hypertension and subjective cognitive decline (SCD) is unclear. Objectives: We determined the influence of high-intensity interval training (HIIT) combined with mind-motor training on cognition and systolic blood pressure (BP) in older adults with hypertension and SCD. Methods: We randomized 128 community-dwelling older adults [age mean (SD): 71.1 (6.7), 47.7% females] with history of hypertension and SCD to either HIIT or a moderate-intensity continuous training (MCT) group. Both groups received 15 min of mind-motor training followed by 45 min of either HIIT or MCT. Participants exercised in total 60 min/day, 3 days/week for 6 months. We assessed changes in global cognitive functioning (GCF), Trail-Making Test (TMT), systolic and diastolic BP, and cardiorespiratory fitness. Results: Participants in both groups improved diastolic BP [F(1, 87.32) = 4.392, p = 0.039], with greatest effect within the HIIT group [estimated mean change (95% CI): −2.64 mmHg, (−4.79 to −0.48), p = 0.017], but no between-group differences were noted (p = 0.17). Both groups also improved cardiorespiratory fitness [F(1, 69) = 34.795, p \u3c 0.001], and TMT A [F(1, 81.51) = 26.871, p \u3c 0.001] and B [F(1, 79.49) = 23.107, p \u3c 0.001]. There were, however, no within- or between-group differences in GCF and systolic BP at follow-up. Conclusion: Despite improvements in cardiorespiratory fitness, exercise of high- or moderate-intensity, combined with mind-motor training, did not improve GCF or systolic BP in individuals with hypertension and SCD. Clinical Trial Registration: ClinicalTrials.gov (NCT03545958)

The Benefits of High-Intensity Interval Training on Cognition and Blood Pressure in Older Adults With Hypertension and Subjective Cognitive Decline: Results From the Heart & Mind Study

Background: The impact of exercise on cognition in older adults with hypertension and subjective cognitive decline (SCD) is unclear. Objectives: We determined the influence of high-intensity interval training (HIIT) combined with mind-motor training on cognition and systolic blood pressure (BP) in older adults with hypertension and SCD. Methods: We randomized 128 community-dwelling older adults [age mean (SD): 71.1 (6.7), 47.7% females] with history of hypertension and SCD to either HIIT or a moderate-intensity continuous training (MCT) group. Both groups received 15 min of mind-motor training followed by 45 min of either HIIT or MCT. Participants exercised in total 60 min/day, 3 days/week for 6 months. We assessed changes in global cognitive functioning (GCF), Trail-Making Test (TMT), systolic and diastolic BP, and cardiorespiratory fitness. Results: Participants in both groups improved diastolic BP [F(1, 87.32) = 4.392, p = 0.039], with greatest effect within the HIIT group [estimated mean change (95% CI): −2.64 mmHg, (−4.79 to −0.48), p = 0.017], but no between-group differences were noted (p = 0.17). Both groups also improved cardiorespiratory fitness [F(1, 69) = 34.795, p \u3c 0.001], and TMT A [F(1, 81.51) = 26.871, p \u3c 0.001] and B [F(1, 79.49) = 23.107, p \u3c 0.001]. There were, however, no within- or between-group differences in GCF and systolic BP at follow-up. Conclusion: Despite improvements in cardiorespiratory fitness, exercise of high- or moderate-intensity, combined with mind-motor training, did not improve GCF or systolic BP in individuals with hypertension and SCD. Clinical Trial Registration: ClinicalTrials.gov (NCT03545958)

Efficient reSe2 photodetectors with CVD single-crystal graphene contacts

Rhenium-based 2D transition metal dichalcogenides such as ReSe2 are suitable candidates as photoactive materials for optoelectronic devices. Here, photodetectors based on mechanically exfoliated ReSe2 crystals were fabricated using chemical vapor deposited (CVD) graphene single-crystal (GSC) as lateral contacts. A "pick & place" method was adopted to transfer the desired crystals to the intended position, easing the device fabrication while reducing potential contaminations. A similar device with Au was fabricated to compare contacts' performance. Lastly, a CVD hexagonal boron nitride (hBN) substrate passivation layer was designed and introduced in the device architecture. Raman spectroscopy was carried out to evaluate the device materials' structural and electronic properties. Kelvin probe force measurements were done to calculate the materials' work function, measuring a minimal Schottky barrier height for the GSC/ReSe2 contact (0.06 eV). Regarding the electrical performance, I-V curves showed sizable currents in the GSC/ReSe2 devices in the dark and under illumination. The devices presented high photocurrent and responsivity, along with an external quantum efficiency greatly exceeding 100%, confirming the non-blocking nature of the GSC contacts at high bias voltage (above 2 V). When introducing the hBN passivation layer, the device under white light reached a photo-to-dark current ratio up to 106.This research was funded by National Funds through the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and projects PTDC/FIS-NAN/3668/2014 (LA2D) and PTDC/FIS-MAC/28114/2017 (POCI-01-0145-FEDER-028114) (GRAPHSENS). A.C. acknowledges the financial support of the project "GEMISGraphene-enhanced Electro-Magnetic Interference Shielding," with the reference POCI-01-0247-FEDER-045939, co-funded by COMPETE 2020-Operational Programme for Competitiveness and Internationalization and FCT-Science and Technology Foundation, under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF)