16 research outputs found

    Effect of N and P Fertilization on Weed Flora of Maize (Zea Mays L.) Crop

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    From May to September 2016, a corn hybrid was sown in a field in central Greece. The experiment was laid out in a randomized complete block design with six replications and five fertilization treatments, namely NutriSphere-N Nitrogen Fertilizer (75%), NutriSphere-N Nitrogen Fertilizer (100%), AVAIL Phosphorus Fertilizer (75%), AVAIL Phosphorus Fertilizer (100%) and unfertilized (control). Data analysis confirmed that the different type of fertilization has a significant effect on the composition of weed flora. In particular, the results of the present study indicated significant differences between the fertilization treatments concerning density and diversity of weeds. Furthermore, weed diversity in the control treatment was highest, while it was lower in plots receiving application of N and P. However, total weed dry mass was lower in plots receiving no fertilizer and P fertilization, and highest in plots receiving N. Differences in terms of weed growth between the two types of fertilization could be attributed to differences revealed in the composition of the weed flora.

    Ice recrystallisation inhibiting polymer nano-objects via saline-tolerant polymerisation-induced self-assembly

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    Chemical tools to modulate ice formation/growth have great (bio)technological value, with ice binding/antifreeze proteins being exciting targets for biomimetic materials. Here we introduce polymer nanomaterials that are potent inhibitors of ice recrystallisation using polymerisation-induced self-assembly (PISA), employing a poly(vinyl alcohol) graft macromolecular chain transfer agent (macro-CTA). Crucially, engineering the core-forming block with diacetone acrylamide enabled PISA to be conducted in saline, whereas poly(2-hydroxypropyl methacrylate) cores led to coagulation. The most active particles inhibited ice growth as low as 0.5 mg mL−1, and were more active than the PVA stabiliser block alone, showing that the dense packing of this nanoparticle format enhanced activity. This provides a unique route towards colloids capable of modulating ice growth

    Effect of Different Types of Fertilization on Vigna unguiculata subsp. sesquipedalis Crop

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    A field experiment was conducted at Pylos, Greece to compare the effect of different types of fertilization on yardlong bean (Vigna unguiculata subsp. sesquipedalis) crop. The conventional treatment plots were fertilized with an inorganic fertilizer, whereas the organic treatments plots received organic compost. Data analysis confirmed no significant correlation between plant height and type of fertilization, but there was significant correlation between length of pods and type of fertilization. In particular, morphological characteristics of yardlong bean were enhanced by inorganic fertilization in comparison with the organic fertilization.  Organic farming increased significantly the number on root nodules in comparison with conventional farming

    Efficacy and Selectivity of Pre- and Post-emergence Herbicides in Chia (Salvia hispanica L.) under Mediterranean Semi-arid Conditions

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    In the present study, the selectivity and efficacy of several post and pre-emergence herbicides in chia (Salvia hispanica L.) were examined. Field experiments were conducted at two locations with different soil types and environmental conditions. Our results showed that the pre-emergence application of pendimethalin, oxyfluorfen and linuron reduced total weed density by 71-74%, 74-82% and 53-55%, respectively. Despite their high effectiveness, the above-mentioned herbicides had a negative effect on plant density and biomass yield. In addition, herbicides bentazon and fluazifop-p-butyl which applied post-emergence did not affect significantly plant height and biomass yield. In conclusion, the herbicides linuron, pendimethalin and oyxfluorfen do not seem to be a viable option for weed control in chia crop, whereas the post-emergence applied herbicides did not affect significantly plants’ growth. Further evaluation of chia tolerance to herbicides is needed under different application rates in order to make safe suggestions for chemical control of weeds

    Quality of life among elderly population

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    Introduction: Quality of Life (QoL) among elderly is an important issue that reflects the status of well-being of this vulnerable population. Aim: This study aims to assess quality of life among elderly population and to examine possible correlations with associated demographic, social and health factors. Material and Method: A cross sectional study was conducted, in which 257 elderlies from Greece were participated. For the data collection the WHOQOL-BREF (30-items Greek version) questionnaire was used as well as a questionnaire with questions about demographic data, social & health factors. Descriptive statistics such as frequencies, means, percentages and standard deviations have been utilized. Inferential statistics such as t-test and pearson r correlation have been used to determined correlations between relevant variables. Level of significance accepted is p < 0.05. Results: From the total 257 elderlies 55.6% (n=143) were women and 44.4% (n=114) were men with a mean age 75.12±8.39. The mean score of overall QoL is 14.14±2.87 and the mean of each factor of WHOQOL-BREF is 13.56±2.79 for physical health, 13.61±2.74 for mental health, 13.72±2.60 for social relationships and 13.70±1.96 for environment. Age, marital status, number of children, level of education, residence area, lifestyle, chronic diseases and serious illnesses are the factors that affects levels of QoL among Greek elderly population Conclusions: Results indicates that levels of QoL between elderly are moderate and many demographic, social and health factors are correlated with QoL status

    Ice recrystallisation inhibiting polymers prevent irreversible protein aggregation during solvent-free cryopreservation as additives and as covalent polymer-protein conjugates

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    Protein storage and transport is essential to deliver therapies (biologics), enzymes for biotechnological applications, and underpins fundamental structural and molecular biology. To enable proteins to be stored and transported it is often essential to freeze them, requiring cryoprotectants such as glycerol or trehalose. Here we explore the mechanisms by which poly(vinyl alcohol), PVA, a potent ice recrystallisation inhibitor protects proteins during freeze/thaw to enable solvent-free cryopreservation with a focus on comparing mixing, verses polymer-protein conjugation. A panel of poly(vinyl alcohol)s are investigated including commercial, well-defined (from RAFT), and PVA-protein conjugates, to map out PVA’s efficacy. Enzymatic activity recovery of lactate dehydrogenase was found to correlate with post-thaw aggregation state (less aggregated protein had greater activity), which was modulated by PVA’s ice recrystallisation inhibition activity. This macromolecular cryoprotectant matched the performance of glycerol, but at lower additive concentrations (as low as 1 mg.mL−1). It was also demonstrated that storage at −20 °C, rather than −80 °C was possible using PVA as a cryoprotectant, which is not possible with glycerol storage. A second protein, green-fluorescent protein (GFP), was used to enable screening of molecular weight effects and to obtain PVA-GFP bioconjugates. It was observed that covalent attachment of RAFT-derived PVA showed superior cryoprotectant activity compared to simple mixing of the polymer and protein. These results show that PVA is a real alternative to solvent-based protein storage with potential in biotechnology, food and therapeutics. PVA is already approved for many biomedical applications, is low cost and available on a large scale, making it an ideal cryoprotectant formulation enhancer

    Poly(vinyl alcohol) molecular bottlebrushes nucleate ice

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    Ice binding proteins (IBP) have evolved to limit the growth of ice but also to promote ice formation by ice-nucleating proteins (INPs). IBPs, which modulate these seemingly distinct processes, often have high sequence similarities, and molecular size/assembly is hypothesized to be a crucial determinant. There are only a few synthetic materials that reproduce INP function, and rational design of ice nucleators has not been achieved due to outstanding questions about the mechanisms of ice binding. Poly(vinyl alcohol) (PVA) is a water-soluble synthetic polymer well known to effectively block ice recrystallization, by binding to ice. Here, we report the synthesis of a polymeric ice nucleator, which mimics the dense assembly of IBPs, using confined ice-binding polymers in a high-molar-mass molecular bottlebrush. Poly(vinyl alcohol)-based molecular bottlebrushes with different side-chain densities were synthesized via a combination of ring-opening metathesis polymerization (ROMP) and reversible addition–fragmentation chain-transfer (RAFT) polymerization, using “grafting-to” and “grafting-through” approaches. The facile preparation of the PVA bottlebrushes was performed via selective hydrolysis of the acetate of the poly(vinyl acetate) (PVAc) side chains of the PVAc bottlebrush precursors. Ice-binding polymer side-chain density was shown to be crucial for nucleation activity, with less dense brushes resulting in colder nucleation than denser brushes. This bio-inspired approach provides a synthetic framework for probing heterogeneous ice nucleation and a route toward defined synthetic nucleators for biotechnological applications

    Synthesis of poly(vinyl alcohol) by blue light bismuth oxide photocatalysed RAFT. Evaluation of the impact of freeze/thaw cycling on ice recrystallisation inhibition

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    Poly(vinyl alcohol), PVA, is the most potent polymeric ice recrystallisation inhibitor (IRI), mimicking a complex function of ice binding proteins. The IRI activity of PVA scales with its molecular weight and hence broad molecular weight distributions in free radical-derived PVAs lead to activity measurements dominated by small amounts of heavier fractions. Well-defined PVA can be prepared by thermally initiated RAFT/MADIX polymerization using xanthates by the polymerization of the less activated monomer vinyl acetate. The low conversions and molecular weights obtained during this approach, often requires feeding of additional initiator and bulk polymerization. Here we employ bismuth oxide photo-RAFT in solution, using blue light (450 nm), rather than previously reported white light, to obtain a library of PVA's. The use of blue light enabled quantitative conversion and acceptable dispersities. Purple light (380 nm) was also used, but asymmetric molecular weight distributions were obtained in some cases. High concentrations of high molecular weight PVA is known to form cryogels during freeze/thaw which has led to speculation this might limit the use of PVA in environments where the temperature cycles e.g. the construction industry. After 4 freeze/thaw cycles there was only small changes in observable IRI for all synthesised PVAs and two commercial standards. In an extended test, activity was retained after 100 freeze/thaw cycles, mitigating concerns that PVA could not be used in situations where freeze/thaw cycles occur. This work presents a convenient method to obtain well-defined PVAs for cryoscience studies compared to conventional thermal-RAFT and indicates that cryogelation concerns may not prevent their use

    Emotional Intelligence and Professional Boredom among Nursing Personnel in Greece

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    Occupational (professional) boredom results in low performance at work. It has been positively associated with high levels of anxiety and depression as well as premature death. However, occupational boredom has not been extensively studied among working nurses. This study aimed to investigate the relationship between emotional intelligence and occupational boredom in nurses working in both public (52.9%) and private (47.1%) health units in Greece. A cross-sectional study was conducted among a convenience sample of 189 nurses (84.7% females) with an average age of 40 years. Emotional intelligence was evaluated with the use of The Trait Emotional Intelligence Questionnaire-Short Form and Professional boredom was assessed with the use of the Boredom Proneness Scale. The majority of Nurses showed relatively high values of total Emotional Intelligence (EI), and marginally low values of overall Professional Boredom. A statistically significant negative correlation was found between the overall Professional Boredom of Nurses and the Well-being, Self-control, Emotionality and Sociability subscales of EI, as well as total EI (p < 0.001). Multiple linear regression analyses showed that the three dimensions of EI (Well-being, Self-Control and Emotionality) explained 39.0% of the variability of the total Professional Boredom of the working Nurses

    Climate Change and Chances for the Cultivation of New Crops

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    Climate change is one of the greatest environmental, economic and social challenges in the history of mankind and nowadays is considered as the biggest environmental problem of the world. Climate change has a significant global impact and therefore Greece has to deal with its effects as well. Agriculture has been unfavourably affected in recent years, as the current and anticipated conditions in many cases seem to be rather prohibitive for the prosperity of the cultivated crops. On the contrary, these new conditions have made it possible for new plant species previously cultivated only in subtropical regions, to thrive in Greece. Moreover, economic reasons would make it rather necessary for the agricultural industry to cultivate alternative crops, which are thoroughly analysed in the present study. Based on Heating Degree Days (HDD) Greece is divided into four climatic zones. The variations in the mean maximum, mean minimum and mean temperature in each climate zone as well as the rainfall over the last 50 years (from 1964 to 2013) are reviewed in this paper. The outcome of this research is that it is not feasible for the studied alternative crops to thrive in all climate zones or vice versa. However, some of them and particularly crops such as quinoa, maca, psyllium, chia, cassava and pecan can be cultivated in all climate zones. It has also to be noted that adequate water is necessary for almost all the examined crops in order to achieve optimal growth and yield and therefore irrigations are rather necessary for specific species and climate zones
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