1,031 research outputs found

    Some families of big and stable bundles on K3 surfaces and on their Hilbert schemes of points

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    Here we investigate meaningful families of vector bundles on a very general polarized K3 surface (X,H) and on the corresponding Hyper--Kähler variety given by the Hilbert scheme of points X[k]:=Hilbk(X), for any integer k⩾2. In particular, we prove results concerning bigness and stability of such bundles. First, we give conditions on integers n such that the twist of the tangent bundle of X by the line bundle nH turns out to be big and stable on X; we then prove a similar result for a natural twist of the tangent bundle of X[k]. Next, by a careful analysis on Segre classes, we prove bigness and stability results for tautological bundles on X[k] arising either from line bundles or from Mukai-Lazarsfeld bundles, as well as from Ulrich bundles on X

    A study of physicochemical properties, volatile component analysis and antioxidative properties of honey

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    Honey samples from five different floral origins were analysed through solid phase microextraction (SPME) with objective to identify and compare their volatile organic compound profile. In addition, the levels of water, HMF, free proline, total acidity, diastase activity and sugar content have also been reported. The samples showed adequate water and HMF content. Total phenolics varied from 75.6 to 98.5mg/g, while total flavonoids were comprised between 1.86 and 4.93 mg/g, expressed as quercetin equivalents (the lowest and highest values were also found for Eucalyptus honey and neem honey, respectively). The IC50 value for DPPH has been found to be ranged from 4.97 to 9.45mg/ml. The highest DPPH RSA was found in Eucalyptus honey, followed by mustard honey and neem hone

    Therapeutic role of MiR-140-5p for the treatment of non-small cell lung cancer

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    Background/Aim: Lung cancer is the second most common cancer in both men and women, after prostate and breast cancer, respectively. There are two main types of primary lung cancer, non-small cell lung cancer (NSCLC), which accounts for approximately 85-90% of all lung cancer cases, and small cell lung cancer (SCLC), which accounts for the other 10-15% of lung cancers. MiRNAs are small molecules that post-transcriptionally regulate many genes and contribute to many disease aetiologies, including tumours. In lung cancer, the down-regulation of miR-140-5p leads to disease progression. Materials and Methods: In this study a miR-140-5p-only treatment and miR-140-5p combined with other chemotherapeutics have been studied in vitro. Results: When transfected into NSCLC, the overexpression of miR-140-5p reduced the migration and invasion properties of malignant cells and, also improved their adhesion onto the artificial extracellular matrix. When miRNA-140-5p replacement treatment was combined with other drugs commonly used in clinical practice, such as gefinitib, DMH1 and cisplatin, it enhanced their efficacy by reducing the migration and invasion ability of cancer cells, thus suggesting that it acts synergistically with known compounds for the treatment of NSCLC. Additionally, some endothelial mesenchymal transition (EMT) markers appeared to be regulated by miR-140-5p. Conclusion: Novel direct targets of miR-140-5p have not been investigated in this study, but our results indicate the involvement of miR-140-5p in lung cancer invasion. The preliminary data from this study imply that when miR-140-5p levels are restored; maybe synergistically support current therapies for NSCLC though further validation, especially in vivo is required

    Changes in carbonyl compounds in Chardonnay and Cabernet Sauvignon wines as a consequence of malolactic fermentation

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    To study changes in carbonyl compounds in Chardonnay and Cabernet Sauvignon wines as a consequence of malolactic fermentation (MLF), wines were fermented by inoculation of commercial strains of Oenococcus oeni, and compared with unfermented (control) wines. Carbonyl compounds were determined by GC/MS analysis on the basis of their O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine derivatives after sample preparation on an ion exchange column to remove pyruvic acid. With MLF, marked changes were revealed, particularly with regard to diacetyl, acetoin and aliphatic saturated aldehydes; the presence of unsaturated aldehydes was also revealed. A significant increase in glycoladehyde was observed, which is presumed to be part of a reduction system with glyoxal. Higher acetoin/diacetyl ratios were found in Chardonnay and higher glycolaldehyde/glyoxal ratios in Cabernet Sauvignon.

    Entrepreneurial approach for open innovation: opening new opportunities, mapping knowledge and highlighting gaps

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    Purpose Since the first definition of open innovation (OI), the indivisible relationship between this concept and entrepreneurship was undeniable. However, the exact mechanisms by which an entrepreneurial approach may benefit OI processes and vice versa are not yet fully understood. The study aims to offer an accurate map of the knowledge evolution of the OI-entrepreneurship relationship and interesting gaps to be filled in the future. Design/methodology/approach The study adopted a bibliometric analysis, coupled with a systematic literature review performed over a data set of 106 peer-reviewed articles published from 2005 to 2020 to identify thematic clusters. Findings The results show five thematic clusters: entrepreneurial opportunities, organisational opportunities, strategic partnership opportunities, institutional opportunities and digital opportunities for OI. Investigating each of them, the authors created a framework that highlights future avenues for further developing the topic. Originality/value This study is the first of its kind to systematise, analyse and critically interpret the literature concerned with the topic of the OI-entrepreneurship

    Efficacy of an Aqueous Extract of Stellaria media (L.) Cyr. against Eimeria legionensis Infection (Apicomplexa: Eimeridae) in Red-legged Partridges (Alectoris rufa)

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    Aims: Coccidiosis is one of the most frequent causes of morbidity and mortality in farmed redlegged partridges (Alectoris rufa). The aim of this study was to evaluate the effects of the plant Stellaria media (Caryophyllaceae) on coccidia-infected red-legged partridges. Methodology: Of 9 replicates of redlegged partridges, each composed by 6 coccidia-infected birds (Eimeria legionensis), 3 replicates (S group) received an aqueous extract (12 ml/l) of S. media with drinking water for 3 consecutive days, while 3 further replicates (D group) received 20% sodium sulfaquinoxaline (2 g/l) with drinking water for 3 consecutive days. The remaining 3 replicates did not receive any treatment (C group). The day before the beginning of the treatment (day 0), the last day of the treatment (day 3) and 7 days after the end of the treatment (day 10), individual fresh faecal samples were collected from all examined birds and analysed for presence and number of coccidian oocysts/gram of faeces (OPG). Data were statistically elaborated with the Analysis of Variance (ANOVA) and the Test of Student-Newman-Keuls for multiple comparisons. The percentage of reduction of the mean OPG number was also assessed. In addition, all birds were clinically observed in order to evaluate the appearance of diarrhoea and of other signs of clinical coccidiosis. Results: Seven days after the end of the treatment, birds of the C group showed diarrhoea and significant (P<0.05) higher OPG numbers respect to those of S and D groups, while no significant differences resulted between S and D groups. Moreover, percentages of OPG reduction of 98.61% and 99.60% and of 99.23% and 78.46% were found at day 3 and day 10 for group S and group D, respectively, while an increased mean OPG number was observed in the untreated group (C). Conclusion: After oral administration to the examined red-legged partridges S. media was able not only to prevent the clinical form of coccidiosis, but also to give a significant reduction of E. legionensis OPG number in faecal samples of birds treated with this plant. This reduction resulted comparable to that observed in animals treated with the commercial drug

    Valorisation of hemp inflorescence after seed harvest: Cultivation site and harvest time influence agronomic characteristics and essential oil yield and composition

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    Cannabis sativa L. is a multipurpose crop, whose industrial varieties, complying with the 0.2% Δ9-tetrahydrocannabinol (THC) threshold set by the EU legislation, can be cultivated without restrictions by farmers. Other than its traditional use as a source of bast fibres from the stems, the fixed oil extracted from its seeds represents a valuable nutritional product. Its inflorescence is also a further exploitable threshing residue originating from seed harvest, as they can be used for the extraction of the essential oil (EO), a high-value added product. This study aims at contributing to the re-evaluation of industrial hemp cultivation as an agro-environmentally sustainable crop for the diversification of Mediterranean cropping systems, by exploring the possibility of recovering the EO from the inflorescence after seed harvest. The influence of the cultivation site (lowland and upland of Pisa province, Tuscany, central Italy) and the harvest time (August and September) have been investigated on the ‘Fedora 17’ monoecious hemp cultivar: the main agronomic traits in term of stem, seed and inflorescence production, as well as essential oil yield and composition have been evaluated. The crops harvested in September exhibited higher total dry yield as well as higher inflorescence and stem yields, while neither the site nor the harvesting period influenced the seed production, which was significantly influenced by harvest time x cultivation site interaction. Both seed fixed oil and crude protein content were affected by the cultivation site only, but in the opposite sense: the highest seed oil content was reached in the upland area, while the plants grown in the plain area exhibited the largest seed protein content. All the extracted EOs were rich in sesquiterpenes (mostly β-caryophyllene and its oxidized derivatives, and α-humulene), but monoterpene hydrocarbons were significantly represented as well (mainly α- and β-pinene, and myrcene). The EOs extraction yields were slightly higher in the earlier harvest for both sites

    Chemical analysis of the essential oils of three cistus species growing in North-West of Algeria

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    The study reports for the first time the chemical composition and the antibacterial activity of the essential oil hydrodistilled from three Cistaceae growing in Algeria: Cistus ladaniferus L., C. albidus L. and C. monspeliensis L. The oils were analyzed by GC-FID and GC-MS analyses. The major components of C. ladaniferus were 5-epi-7-epi-α-eudesmol (13.6%) and borneol (12.5%) whereas for C. albidus the main constituents were epi-α-bisabolol (11.4%) and β-bourbonene (8.7%). Epi-13-manoyl oxide (28.6%), kaur-16-ene (8.1%) and nonanal (5.4%) were the principal ones for C. monspeliensis. In vitro, antimicrobial activity of the oils was investigated against nine microorganisms by disk diffusion and agar dilution assays. The Gram-positive bacteria resulted sensitive to the three oils, especially Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923. The volatiles of C. monspeliensis showed the best activity compared with other oils, comparable to or better than Gentamicin, a conventional antibiotic used as positive control in this study. The minimum inhibitory concentration (MIC) value of the oil was 0.25μg/L

    Scutellaria caucasica A. Ham.: Morphological features and headspace characterization

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    In the context of a wide research project, a micromorphological and phytochemical characterization was performed on the vegetative and reproductive organs of Scutellaria caucasica A. Ham. (Lamiaceae), cultivated at the Ghirardi Botanic Garden (Toscolano Maderno, BS, Lombardy, Italy). The morphological survey revealed the presence of both non-glandular and glandular trichomes. The latter belonged to three different morphotypes: peltate, short-stalked and long-stalked capitate. Histochemical assays demonstrated that the terpenes biosynthesis mainly took place in the peltates, while short-stalked capitates secreted only polysaccharides; the long-stalked ones mainly produced polysaccharides, coupled with terpene and polyphenolic fractions. An element of novelty was represented by the characterization of the VOC emission profile. Leaves and flowers showed differences in their emissions: the floral profile had a higher number of compounds than that of the leaves (37 vs 29), with a higher heterogeneity. The almost totality of the leaf profile was characterized by sesquiterpene hydrocarbons (98.8 %), while the flowers presented a more varied composition, with sesquiterpene hydrocarbons (87.2 %), monoterpenes (10.4 % oxygenated, 1.8 % hydrocarbons) and non-terpenes derivatives (0.6 %). The most abundant compounds were \u3b3-muurolene (42.6 %) and \u3b2-caryophyllene (35.0 %) in the leaves and in the flowers, respectively. In the flower headspace, 16 exclusive compounds were identified, among which germacrene D (31.7 %) dominated; leaves had 8 exclusive compounds, with valencene (1.8 %) as the most represented one. 21 common compounds were revealed: \u3b2-caryophyllene (34.1 % leaves; 35.0 % flowers), \u3b1-humulene (3.0 % leaves; 3.1 % flowers), alloaromadendrene (2.4 % leaves; 1.0 % flowers), \u3b1-copaene (2.1 % leaves; 2.7 % flowers) and \u3b2-copaene (2.2 % leaves; 1.5 % flowers) were the most abundant ones. \u3b3-Muurolene relative abundances (42.6 % leaves; 0.7 % flowers) were very different between the two profiles. Overall, this work represented the first multidisciplinary study on S. caucasica, combining a scientific research approach with the policies of the Open Science

    Aroma characterization of ripe date fruits (Phoemix dactylifera L.) from Algeria

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    The headspace of eight Algerian date varieties with low market value were analyzed for their aroma compounds using solid phase micro extraction and gas chromatography combined with mass spectrometry. In this study, 61 identified compounds were categorized in various chemical classes on the basis of their functional groups, alcohols, esters, aldehydes, terpenoids, ketones, hydrocarbons, and ethers. Twenty specific volatiles were found to be representative of a single variety and four shared molecules were exclusively observed in all the studied dates. Some dates such as Bent Qbala, Litima, and Timjouhart were statistically different from the other varieties which presented on the contrary a significant similarity between them. In the present study, forty eight new volatile compounds were identified which could be useful for the characterization of the Algerian date
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