787 resultados para Phenolic panels in job
Resumo:
The paper presents a critical analysis of the extant literature pertaining to the networking behaviours of young jobseekers in both offline and online environments. A framework derived from information behaviour theory is proposed as a basis for conducting further research in this area. Method. Relevant material for the review was sourced from key research domains such as library and information science, job search research, and organisational research. Analysis. Three key research themes emerged from the analysis of the literature: (1) social networks, and the use of informal channels of information during job search, (2) the role of networking behaviours in job search, and (3) the adoption of social media tools. Tom Wilson’s general model of information behaviour was also identified as a suitable framework to conduct further research. Results. Social networks have a crucial informational utility during the job search process. However, the processes whereby young jobseekers engage in networking behaviours, both offline and online, remain largely unexplored. Conclusion. Identification and analysis of the key research themes reveal opportunities to acquire further knowledge regarding the networking behaviours of young jobseekers. Wilson’s model can be used as a framework to provide a holistic understanding of the networking process, from an information behaviour perspective.
Resumo:
International audience
Resumo:
Wild strawberry, Fragaria vesca L., belongs to Rosaceae family and is commonly found in roadsides and slopes [1]. The most consumed parts of this plant are its sweet small fruits, which constitute a source of vitamins and phenolic compounds, being also used in infusions due to their organoleptic properties and for the treatment of some intestinal disorders [2, 3]. In the present work, F. vesca fruits were evaluated for their nutritional value and further used in the preparation of infusions. The chemical composition of the fruits and corresponding infusions was determined in terms of soluble sugars, organic acids, tocopherols, folates (by HPLC coupled to different detectors), phenolic compounds (by HPLC-DAD/ESI-MS) and mineral elements (atomic absorption spectroscopy). Some of these bioactive compounds were correlated with antioxidant and antibacterial properties evaluated either in infusions as also in hydromethanolic extracts. Carbohydrates were the main macronutrients in the fruits, followed by fat and proteins. Regarding the fatty acids, polyunsaturated fatty acids showed higher prevalence, mainly due to the presence of D-linolenic (Cl8:3n3) and y-linolenic (Cl8:3n6) acids. Sucrose and citric acid were, respectively, the main sugar and organic acid found in the fruits and in its infusions. The microelement found in higher amounts in both samples was manganese, while potassium and calcium were the macroelements present in higher levels in the fruits and infusions, respectively. Both samples presented folates and tocopherols, being ytocopherol the main isoform detected in the fruits, while a-tocopherol was the only isoform quantified in the infusion. The hydromethanolic extract prepared from the fruits gave higher antioxidant and antibacterial activities, namely against Escherichia coli and Pseudomonas aeruginosa, than the infusion; it also showed capacity to inhibit the formation of bacterial biofilm. Both bioactivities are highly correlated with the presence of phenolic compounds, in which the major are ellagic acid derivatives (sanguiin hlO) followed by tlavan 3-ols ((+)catechin) and anthocyanin compounds (pelargonidin-3-glucoside). Although fruits of wild F. vesca are mainly consumed in fresh, this study also proves the potentiality of their infusions as a source of bioactive molecules and properties.
Resumo:
Salvia species are used worldwide for medicine purposes. In general, these medicinal plants have high amounts of flavonoids and phenolic acids, that are thought to be closely related to their health properties [1,2]. In this work, the aerial parts of Salvia farinacea, Salvia mexico, Salvia greggii and Salvia officinalis were extracted with hot water [3]. Extracts were evaluated for their total phenolic content by an adaptation of the Folin-Ciocalteu method and further analysed by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative ion mode [4], in order to identify their individual phenolic constituents. The aqueous extracts of S. farinacea, S. mexico, S. officinalis and S. greggii contained, respectively, 106±13, 159±38, 175±46 and 136±1 μg GAE/mg of total phenolics. These four species were characterized by a clear prevalence of caffeic acid derivatives, in particular of rosmarinic acid (MW 360), that is generally the most abundant phenolic compound in Salvia species [2,3]. In addition, S. mexico and S. officinalis contained moderate amounts of salvianolic acid B (MW 718). Among these two, S. mexico was richer in O-caffeoylquinic acid (MW 354), while the latter presented high amounts of salvianolic acid K (MW 556) and moderate amounts of its structural isomer. All the extracts were enriched in flavones: S. farinacea and S. officinalis contained high amounts of luteolin-O-glucuronide while S. mexico contained luteolin-C-glucoside with respective characteristic mass spectrometry fragmentation pattern m/z at 461→285 and m/z at 447→357, 327. Similarly, S. greggii extract presented high content of luteolin-7-O-glucoside ([M-H]− at m/z 447→ 285) and luteolin-C-glucoside and moderate quantities of apigenin-C-hexoside ([M-H]− at m/z 431→341, 311). Further studies are being undertaken in order to understand the contribution of these phenolic constituents in the biological activities of Salvia plants.
Resumo:
Salvia species are used worldwide for medicine purposes. In general, these medicinal plants have high amounts of flavonoids and phenolic acids, that are thought to be closely related to their health properties [1,2]. In this work, the aerial parts of Salvia farinacea, Salvia mexico, Salvia greggii and Salvia officinalis were extracted with hot water [3]. Extracts were evaluated for their total phenolic content by an adaptation of the Folin-Ciocalteu method and further analysed by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative ion mode [4], in order to identify their individual phenolic constituents. The aqueous extracts of S. farinacea, S. mexico, S. officinalis and S. greggii contained, respectively, 106±13, 159±38, 175±46 and 136±1 μg GAE/mg of total phenolics. These four species were characterized by a clear prevalence of caffeic acid derivatives, in particular of rosmarinic acid (MW 360), that is generally the most abundant phenolic compound in Salvia species [2,3]. In addition, S. mexico and S. officinalis contained moderate amounts of salvianolic acid B (MW 718). Among these two, S. mexico was richer in O-caffeoylquinic acid (MW 354), while the latter presented high amounts of salvianolic acid K (MW 556) and moderate amounts of its structural isomer. All the extracts were enriched in flavones: S. farinacea and S. officinalis contained high amounts of luteolin-O-glucuronide while S. mexico contained luteolin-C-glucoside with respective characteristic mass spectrometry fragmentation pattern m/z at 461→285 and m/z at 447→357, 327. Similarly, S. greggii extract presented high content of luteolin-7-O-glucoside ([M-H]− at m/z 447→ 285) and luteolin-C-glucoside and moderate quantities of apigenin-C-hexoside ([M-H]− at m/z 431→341, 311). Further studies are being undertaken in order to understand the contribution of these phenolic constituents in the biological activities of Salvia plants.
Resumo:
Thymus plants comprise distinct species with claimed health properties [1], commonly associated to their essential oils and phenolic compounds. Albeit that, the phenolic composition and the biological activities of many Thymus species remain unclear. This work aimed to elucidate the phenolic composition and antioxidant properties of aqueous extracts from Thymus herba barona, Thymus caespetitus and Thymus fragrantissimus. The aqueous extracts of the three Thymus species were evaluated for their total phenolic compounds by an adaptation of the Folin-Ciocalteu method [2], and individual phenolic compounds were identified by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative mode. The antioxidant activity of each extract was carried out by DPPH● scavenging assay and ferric reducing antioxidant power assays [3]. Total phenolic compounds in the three extracts ranged from 236±27 (T. caespetitus) to 273±17 μg GAE/mg (T. fragrantissimus). Similarly to other Thymus species [1,4], these extracts were rich in caffeic acid derivatives (characteristic UV spectra maxima at 290 and 328 nm) and mainly composed of rosmarinic acid (MW 360). Other caffeic acid derivatives included salvianolic acid K (MW 556) and 3′-O-(8″-Z-caffeoyl)rosmarinic acid (MW 538). High amounts of the flavone luteolin-O-glucuronide ([M-H]− at m/z 461→285) were found in T. caespetitus while the others species contained moderate amounts of this compound. T. herba barona, T. caespetitus and T. fragrantissimus extracts showed high DPPH radical scavenge ability (EC50 values 11.6±0.9, 13.8±0.6 and 10.9±1.2 μg/mL respectively), as well as high reducing power (EC50 values of 35.1±4.5, 39.3±2.7 and 32.4±4.3 μg/mL, respectively), that were comparable to those of reference compounds. This work is an important contribution for the phytochemical characterization and the antioxidant capacity of these three Thymus species.
Resumo:
Thymus plants comprise distinct species with claimed health properties [1], commonly associated to their essential oils and phenolic compounds. Albeit that, the phenolic composition and the biological activities of many Thymus species remain unclear. This work aimed to elucidate the phenolic composition and antioxidant properties of aqueous extracts from Thymus herba barona, Thymus caespetitus and Thymus fragrantissimus. The aqueous extracts of the three Thymus species were evaluated for their total phenolic compounds by an adaptation of the Folin-Ciocalteu method [2], and individual phenolic compounds were identified by high performance liquid chromatography associated with electrospray mass spectrometry (HPLC-DAD-ESI-MSn) in the negative mode. The antioxidant activity of each extract was carried out by DPPH● scavenging assay and ferric reducing antioxidant power assays [3]. Total phenolic compounds in the three extracts ranged from 236±27 (T. caespetitus) to 273±17 μg GAE/mg (T. fragrantissimus). Similarly to other Thymus species [1,4], these extracts were rich in caffeic acid derivatives (characteristic UV spectra maxima at 290 and 328 nm) and mainly composed of rosmarinic acid (MW 360). Other caffeic acid derivatives included salvianolic acid K (MW 556) and 3′-O-(8″-Z-caffeoyl)rosmarinic acid (MW 538). High amounts of the flavone luteolin-O-glucuronide ([M-H]− at m/z 461→285) were found in T. caespetitus while the others species contained moderate amounts of this compound. T. herba barona, T. caespetitus and T. fragrantissimus extracts showed high DPPH radical scavenge ability (EC50 values 11.6±0.9, 13.8±0.6 and 10.9±1.2 μg/mL respectively), as well as high reducing power (EC50 values of 35.1±4.5, 39.3±2.7 and 32.4±4.3 μg/mL, respectively), that were comparable to those of reference compounds. This work is an important contribution for the phytochemical characterization and the antioxidant capacity of these three Thymus species.
Resumo:
Plant tissue and organ culture has been extensively used from the beginning of the XX century for the study and comprehension of some primary biological mechanisms such as morphogenesis. However, with the increasing demand of the market for novel products derived from plants, in vitro culture became a reliable technique for the mass production of plant material. Moreover, the potential to use this technique for the production of some bioactive compounds, such as phenolic compounds, is immense since it allows the manipulation of the biosynthetic routes to increase the production and accumulation of specific compounds. This work intends to make a brief historical review of in vitro culture, highlighting its use for the production of bioactive compounds. Also, emphasizes the importance of phenolic compounds for the consumer as well reviews the metabolic pathways involved in its production in plant cells. Furthermore, it was carried out a comprehensive study on the work developed for the production of plant phenolic compounds in in vitro cultures, as well as on the type of elicitors used to increase of the same production; also a brief highlighting of the phenolic compounds which serve as elicitors. There are numerous reports directed to the production of phenolic extracts in in vitro plant cultures, however there is a lack in the production of individual phenolic compounds mainly due to the complexity of the biosynthetic routes and extraction procedures. Elicitation procedures are often used to increase the production of phenolics, archieving in most cases higher yields than in non-elicitated cultures. The increasing production of bioactive phenolic extracts/compounds allows for their further applicability, namely in the industry of functional foods or in pharmaceutical/medical fields.
Resumo:
The balance between oxidation and reduction is important for maintaining a healthy biological system. Oxidative stress results from an imbalance between excessive formation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS) and limited endogenous defense systems, and this imbalance can adversely alter lipids, proteins and DNA, causing a number of human diseases. Thus, exogenous antioxidants that can neutralize the effect of free radicals are needed to diminish the cumulative effects of oxidative damage over human life span. Current research reveals that phenolic compounds in plants possess high antioxidant activity and free radical scavenging capacity and can prevent the body from oxidative damage over human life span. This review focuses on the present understanding of free radicals and antioxidants and their importance in human health and disease. Information about the chemical features of free radicals as well as their deleterious effects on cell structures is reviewed. The chemical structure and anti-oxidative mechanisms of essential polyphenols and their potential health benefits are presented. In addition, the limitation of natural antioxidants and a perspective on likely future trends in this field are also discussed.
Resumo:
Strawberries are an important source of phytochemicals, namely vitamins and phenolic compounds such as anthocyanins and tannins with antioxidant properties [1]. The yield and phenolic content of natural extracts are dependent on the conditions used for extraction [2]. In the present work three different types of extracting solutions (methanol, ethanol:water and aceton:water), two times of extraction (15 and 60 min) and three ratios of solid/solvent (5/25, 5/50 and 5/100 g/mL) were tested in order to evaluate the efficiency of the extraction of phenolic compounds. Phenolic compounds were determined by Folin-Ciocalteu method [3]. Each assay was performed in triplicate. Regarding the extraction solution, it was possible to observe a slight tendency towards a higher efficiency of acetone:water (AcO:H2O, 60:40), but the differences mioght not be statistically significant. A longer time of contact, 60 min as opposed to 15 min, did not show advantages in the yield of extraction. Considering the factors under study, the results obtained showed that volume of extraction solution was the parameter that most influenced the values obtained. Using a higher volume lead to an increase in the amount of phenolic compounds extracted, in a more pronounced way for 15 min of extraction. For a volume of 25 mL the amount of phenolic compounds quantified ranged from 2.13-2.41 mg GAE/g, and increased 30-68% when it was used 50 mL of solution. Using 100 mL of solution, it was extracted twice as double of phenolic compounds. In case of 60 min, the amount of phenolic compounds quantified in samples obtained with 25 mL of solution ranged from 2.32-2.97 mg GAE/g, and increased for 2.43-4.27 mg GAE/g and 3.98-4.68 mg GAE/g when was used 50 and 100 mL, respectively.
Resumo:
In organic and biodynamic vineyards, canopy management practices should be carefully and timely modulated, particularly in a context of climate change, for successfully achieving balanced plants, ventilated and exposed berries, elevated grape and wine quality. In 2013 and 2014, characterized by contrasting climatic conditions, the implications of post-veraison (late) or pea-size trimming, post-veraison or pre-harvest late defoliations and shoot-positioning (post-veraison) were assessed against long-shoots non treated controls, under field conditions on organically-cultivated cv. Sangiovese. The key agronomic and enological relevance of late trimming and defoliations clearly emerged in both seasons. Berry skin phenolics (e.g. anthocyanins, flavonols) increased markedly, without changes in technological parameters. In case of early trimming, such positive effects were observed only in 2013. Maintaining long shoots for shading decreased anthocyanins, flavonols and total phenolics concentrations and promoted the production of compact bunches. Experimental data strongly designated late trimming, a practice proved to contain yield and bunch compactness, as a valuable alternative to cluster thinning. Late trimming, defoliations and shoot positioning reduced the severity of Botrytis cluster rot. The highest levels of berry skins phenolic compounds in late trimmed and defoliated plants could have contributed control the severity of this pathogen. The enological benefits induced by late trimming and defoliations and shoot positioning emerged in both young and aged wines. For the first time, cell cultures from cv. Sangiovese berry tissues were obtained and enabled to investigate, in controlled conditions, the relations between mechanisms regulating secondary metabolism in grapevine cells and changes induced by environmental and agronomic factors. The Doctoral Dissertation strongly highlights the need to consider, for a proper interpretation of the multiple modifications induced by canopy management strategies, physiological mechanisms other than the canonic source-sink relationships, in particular their impact on the vine hormonal status.
Resumo:
While the need for teamwork skills consistently appears in job advertisements across all sectors, the development of these skills for many university students (and some academic staff) remains one of the most painful and often complained about experiences. This presentation introduces the final phase of a project that has investigated and analysed the design of teamwork assessment across all discipline areas in order to provide a university-wide protocol for this important graduate capability. The protocol concentrates best practice guidelines and resources across a range of approaches to team assessment and includes an online diagnostic tool for evaluating the quality of assessment design. Guide-lines are provided for all aspects of the design process such as the development of real-world relevance; choosing the ideal team structure; planning for intervention and conflict resolution; and selecting appropriate marking options. While still allowing academic staff to exercise creativity in assessment design; the guidelines increase the possibility of students’ experiencing a consistent and explicit approach to teamwork throughout their course. If implementation of the protocol is successful, the project team predicts that the resulting consistency and explicitness in approaches to teamwork will lead to more coherent skill development across units, more realistic expectations for students and staff and better communication between all those participating in the process.
Resumo:
Cold-formed steel stud walls are a major component of Light Steel Framing (LSF) building systems used in commercial, industrial and residential buildings. In the conventional LSF stud wall systems, thin steel studs are protected from fire by placing one or two layers of plasterboard on both sides with or without cavity insulation. However, there is very limited data about the structural and thermal performance of stud wall systems while past research showed contradicting results, for example, about the benefits of cavity insulation. This research was therefore conducted to improve the knowledge and understanding of the structural and thermal performance of cold-formed steel stud wall systems (both load bearing and non-load bearing) under fire conditions and to develop new improved stud wall systems including reliable and simple methods to predict their fire resistance rating. Full scale fire tests of cold-formed steel stud wall systems formed the basis of this research. This research proposed an innovative LSF stud wall system in which a composite panel made of two plasterboards with insulation between them was used to improve the fire rating. Hence fire tests included both conventional steel stud walls with and without the use of cavity insulation and the new composite panel system. A propane fired gas furnace was specially designed and constructed first. The furnace was designed to deliver heat in accordance with the standard time temperature curve as proposed by AS 1530.4 (SA, 2005). A compression loading frame capable of loading the individual studs of a full scale steel stud wall system was also designed and built for the load-bearing tests. Fire tests included comprehensive time-temperature measurements across the thickness and along the length of all the specimens using K type thermocouples. They also included the measurements of load-deformation characteristics of stud walls until failure. The first phase of fire tests included 15 small scale fire tests of gypsum plasterboards, and composite panels using different types of insulating material of varying thickness and density. Fire performance of single and multiple layers of gypsum plasterboards was assessed including the effect of interfaces between adjacent plasterboards on the thermal performance. Effects of insulations such as glass fibre, rock fibre and cellulose fibre were also determined while the tests provided important data relating to the temperature at which the fall off of external plasterboards occurred. In the second phase, nine small scale non-load bearing wall specimens were tested to investigate the thermal performance of conventional and innovative steel stud wall systems. Effects of single and multiple layers of plasterboards with and without vertical joints were investigated. The new composite panels were seen to offer greater thermal protection to the studs in comparison to the conventional panels. In the third phase of fire tests, nine full scale load bearing wall specimens were tested to study the thermal and structural performance of the load bearing wall assemblies. A full scale test was also conducted at ambient temperature. These tests showed that the use of cavity insulation led to inferior fire performance of walls, and provided good explanations and supporting research data to overcome the incorrect industry assumptions about cavity insulation. They demonstrated that the use of insulation externally in a composite panel enhanced the thermal and structural performance of stud walls and increased their fire resistance rating significantly. Hence this research recommends the use of the new composite panel system for cold-formed LSF walls. This research also included steady state tensile tests at ambient and elevated temperatures to address the lack of reliable mechanical properties for high grade cold-formed steels at elevated temperatures. Suitable predictive equations were developed for calculating the yield strength and elastic modulus at elevated temperatures. In summary, this research has developed comprehensive experimental thermal and structural performance data for both the conventional and the proposed non-load bearing and load bearing stud wall systems under fire conditions. Idealized hot flange temperature profiles have been developed for non-insulated, cavity insulated and externally insulated load bearing wall models along with suitable equations for predicting their failure times. A graphical method has also been proposed to predict the failure times (fire rating) of non-load bearing and load bearing walls under different load ratios. The results from this research are useful to both fire researchers and engineers working in this field. Most importantly, this research has significantly improved the knowledge and understanding of cold-formed LSF walls under fire conditions, and developed an innovative LSF wall system with increased fire rating. It has clearly demonstrated the detrimental effects of using cavity insulation, and has paved the way for Australian building industries to develop new wall panels with increased fire rating for commercial applications worldwide.
Resumo:
Adopting a model of job enrichment we report on a longitudinal case investigating the perceived impact of an Enterprise Resource Planning (ERP) system on user job design characteristics. Our results indicated that in the context of an ERP geared towards centralisation and standardisation the extent to which users perceived an increase or decrease in job enrichment was associated with aspects such as formal authority and the nature of their work role. Experienced operational employees proficient in the original legacy system perceived ERP system protocols to constrain their actions, limit training and increase dependence on others in the workflow. Conversely, managerial users reported a number of benefits relating to report availability, improved organisational transparency and increased overall job enrichment. These results supported our argument concerning the relationship between ERPs with a standardisation intent and positive job enrichment outcomes for managerial users and negative job-related outcomes for operational users.
Resumo:
In this issue of Cancer Discovery, Guagnano and colleagues use a large and diverse annotated collection of cancer cell lines, the Cancer Cell Line Encyclopedia, to correlate whole-genome expression and genomic alteration datasets with cell line sensitivity data to the novel pan-fibroblast growth factor receptor (FGFR) inhibitor NVP-BGJ398. Their findings underscore not only the preclinical use of such cell line panels in identifying predictive biomarkers, but also the emergence of the FGFRs as valid therapeutic targets, across an increasingly broad range of malignancies.