Highly efficient electrochemical and chemical hydrogenation of 4-nitrophenol using recyclable narrow mesoporous magnetic CoPt nanowires

Toxic nitro-compounds, such as 4-nitrophenol, are one of the most common wastewater industrial pollutants. Thus, efficient ways to neutralize them are actively pursued. Here novel procedures to degrade this type of compounds based on the use of mesoporous magnetic nanowires are demonstrated. Fully-mesoporous magnetic narrow (25 nm) CoPt nanowires with an extraordinary effective area are grown by ionic liquid-in-water microemulsions in alumina templates. These mesoporous nanowires are shown to be efficient catalysts for the hydrogenation of 4-nitrophenol by electro-catalysis. Additionally, these nanowires also present an exceptional conventional catalytic activity when used in conjunction with NaBH4, particularly when magnetic stirring is utilized. In fact, magnetically actuated mesoporous CoPt nanowires drastically outperform all state-of-the-art 4-nitrophenol catalysts. Additionally, given their magnetic character, these nanowires can be easily recycled and reused. Thus, the outstanding catalytic performance of mesoporous CoPt nanowires makes them excellent candidates for wastewater treatment agents

Metastable Random Field Ising model with exchange enhancement: a simple model for Exchange Bias

We present a simple model that allows hysteresis loops with exchange bias to be reproduced. The model is a modification of the T=0 random field Ising model driven by an external field and with synchronous local relaxation dynamics. The main novelty of the model is that a certain fraction f of the exchange constants between neighbouring spins is enhanced to a very large value J_E. The model allows the dependence of the exchange bias and other properties of the hysteresis loops to be analyzed as a function of the parameters of the model: the fraction f of enhanced bonds, the amount of the enhancement J_E and the amount of disorder which is controlled by the width sigma of the Gaussian distribution of the random fields.Comment: 8 pages, 11 figure

Morpho-physiological responses of alamo switchgrass during germination and early seedling stage under salinity or water stress conditions

Switchgrass (Panicum virgatum L.) is a warm perennial grass with valuable characteristics as a biofuel crop. To avoid competition with food crops, biofuel crops will be likely relegated to less productive soils such as marginal lands. Consequently, the salinity and water scarcity problems that commonly affect marginal lands compromise biofuel crop germination, emergence, and seedling establishment. The aims of this study were to study the germination and seedling growth of switchgrass under salinity and water stress and to describe the morpho-anatomical responses of the roots and leaves in the seedlings to these stress conditions. The effect of salt and water stress was assessed using sodium chloride (NaCl) and polyethylene glycol (PEG) 8000 at the same water potentials of − 0.8, − 1.0, and − 1.2 MPa. Seeds were moist prechilled for 7 days at 5 °C and germinated at 30/15 °C (8 h light/16 h dark). NaCl treatments (− 0.8 and − 1.0 MPa) delayed germination rates but did not reduce the final germination percentage, whereas at a lower potential (− 1.2 MPa), the final germination percentage was diminished. The effects of PEG (− 1.0 and − 1.2 MPa) on the germination rate and final percentage were more detrimental than those induced by isosmotic concentrations of NaCl. PEG and NaCl reduced significantly the vigor index of − 0.8 to − 1.2 MPa. The morphoanatomical changes such as the reduction in the root cross-sectional area and the thickening of the endodermis walls for both stress conditions and aerenchyma formation in the cortex under salinity could significantly contribute in the survival and tolerance during the early seedling stages

Non-chemical weed management for sustainable rice production in the Ebro Delta

Weed control is one of the major challenges in rice cultivation, and the use of agrochemicals in this crop is severely restricted under the new European agricultural policy. Therefore, new effective non-chemical weed control agents are the key to sustain European rice production. We investigated four non-chemical weed management strategies in the Ebro Delta in north-eastern Spain, two in dry-seeded rice fields and two in water-seeded rice fields. In addition, two controls per sowing conditions were included; a positive control consisting in chemical herbicides treatment and a negative control consisting in no weeding and no seeding. In all tests but negative controls, the rice variety Argila was employed. "Simple dry seeding" was the best treatment for dry seeding, while "false seeding" (stale seed bed) and planting was the best performing under water seeding conditions. Both mentioned treatments were as effective as chemical control in reducing the density of weeds and the weeding time for those species more abundant in Ebro Delta rice fields (i.e. Echinochloa oryzoides, Echinochloa crus-galli, Scirpus maritimus and Heteranthera reniformis). Our results indicated that some of the non-chemical weed control methods can reduce weed pressure to levels similar to standard chemical herbicide treatments under certain seeding conditions

The ECOS-16 questionnaire for the evaluation of health related quality of life in post-menopausal women with osteoporosis

BACKGROUND: The aim of this study is to validate the questionnaire ECOS-16 (Assessment of health related quality of life in osteoporosis) for the evaluation of health related quality of life (HRQoL) in post-menopausal women with osteoporosis. METHODS: An observational, prospective and multi-centre study was carried out among post-menopausal women with osteoporosis in primary care centres and hospital outpatient clinics. All patients attended 2 visits: at baseline and at 6 months. In addition, the subgroup of outpatients attended another visit a month after the baseline to assess the test-retest reliability. The psychometric properties of the questionnaire were evaluated in terms of feasibility, validity (content validity and construct validity) and internal consistency in baseline, and in terms of test-retest reliability and responsiveness to change in visit at month and visit at 6 months, respectively. In all visits, ECOS-16, EUROQoL-5D (EQ-5D) and four 7-point items about health status (general health status, back pain, limitation in daily activities and emotional status) were administered, whereas only outpatients were given MINI-OQLQ (Mini Osteoporosis Quality of Life Questionnaire), besides all clinical variables; and sociodemographic variables at baseline. RESULTS: 316 women were consecutively included, 212 from primary care centres and 104 from hospital outpatient clinics. Feasibility: 94.3% of patients answered all items of the questionnaire. The mean administration time was 12.3 minutes. Validity: factor analysis suggested that the questionnaire was unidimensional. In the multivariate analysis, patients with vertebral fractures, co-morbidity and a lower education level showed to have worse HRQoL. Moderate to high correlations were found between the ECOS-16 score and the other health status questionnaires (0.47–0.82). Reliability: internal consistency (Cronbach's α) was 0.92 and test-retest reliability (ICC) was 0.80. Responsiveness to change: ECOS-16 scores increased according to change perceived by the patient, as well as the effect size (ranges between 1.35 to 0.43), the greater the perception of change in patients' general health status, the greater the changes in patients' scores. The Minimal Clinically Important Difference (MCID) suggested a change of 0.5 points in the ECOS-16 score, representing the least improvement in general health status due to their osteoporosis: "slightly better". CONCLUSION: ECOS-16 has been proven preliminarily to have good psychometric properties, so that it can be potentially a useful tool to evaluate HRQoL of post-menopausal women with osteoporosis in research and routine clinical practice

Photosynthesis, resource acquisition and growth responses of two biomass crops subjected to water stress

This study compares photosynthesis, growth, 13C and 15N labelling patterns of two biomass crops (Arundo donax L. and Panicum virgatum L.) grown under water stress in greenhouse conditions. Plants were exposed to three water stress levels: control (C, 100% Pot Capacity), mild stress (MS, 50% PC) and severe stress (SS, 25% PC). Photosynthesis, fluorescence parameters and relative water content were measured at the beginning (Ti) and the end of the experiment (Tf). Biomass parameters were measured at Tf. Short-term double labelling with 13C and 15N stable isotopes was performed in both species. Isotopic analyses of total organic matter, total soluble sugars and the CO2 respired were undertaken at T0 (prelabelling), T1 (24h after labelling) and T2 (7 days after labelling). Immediately after the 13C and 15N labelling, stems and rhizomes seemed to be the main sinks for labelled carbon and nitrogen in both species. Moreover, not all of the labelled carbon and nitrogen substrate was used by plant metabolism after seven days. Decreases in photosynthesis parameters were observed as a consequence of the increase in water stress (WS) in both species, with a greater magnitude decline in giant reed than in switchgrass. A decrease in height, number of green leaves and total dry weight due to WS was observed in both species. Both species were more 13C-enriched and more 15N-depleted during the increases in WS due to lower stomatal conductance and transpiration. In general, WS accelerated plant phenology and, consequently, the accumulation of storage compounds in the rhizome occurred in response to stress. This effect was more clearly visible in switchgrass than in giant reed

Drought Impact on the Morpho‐Physiological Parameters of Perennial Rhizomatous Grasses in the Mediterranean Environment

The selection of non‐food crops for bioenergy production in limiting environments is a priority for energy security and climate change mitigation. Therefore, more studies are needed on the interactions between species and environmental factors in specific sites which allows their selection for biomass production. The objective of this work is to study the impact of drought on the morpho‐physiological parameters of perennial rhizomatous grasses Panicum virgatum L., Miscanthus × giganteus, and Arundo donax L. in the Mediterranean environment. Plants were grown on field and trials were carried out under support‐irrigation and rainfed conditions during two consecutive years. Morpho‐physiological parameters were measured in May, June and August, and dry biomass at the end of the experiment. Under rainfed conditions, A. donax presented the highest photosynthesis rate (25, 15 and 10 CO2 m−2 s−1), relative water content (85-90%), and dry biomass (~4500 g plant−1) compared with P. virgatum (20, 5 and 5 CO2 m−2 s−1, 65-85% RWC and ~1400 g plant−1) and Miscanthus (18, 4 and 0 CO2 m−2 s−1, 80-10% RWC and ~260 g plant−1). It is concluded that A. donax would be the best perennial rhizomatous grass to be used as bioenergy crop under Mediterranean conditions

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