1. |
- Bernal, Ximena E., et al.
(author)
-
Empowering Latina scientists
- 2019
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 363:6429, s. 825-826
-
Journal article (other academic/artistic)
|
|
2. |
- Backes, Claudia, et al.
(author)
-
Production and processing of graphene and related materials
- 2020
-
In: 2D Materials. - : IOP Publishing. - 2053-1583. ; 7:2
-
Journal article (peer-reviewed)abstract
- We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. Section I is devoted to 'bottom up' approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers 'top down' techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers' and modified Hummers' methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resource-consuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown. Section VIII discusses advances in GRM functionalization. A broad range of organic molecules can be anchored to the sp(2) basal plane by reductive functionalization. Negatively charged graphene can be prepared in liquid phase (e.g. via intercalation chemistry or electrochemically) and can react with electrophiles. This can be achieved both in dispersion or on substrate. The functional groups of GO can be further derivatized. Graphene can also be noncovalently functionalized, in particular with polycyclic aromatic hydrocarbons that assemble on the sp(2) carbon network by pi-pi stacking. In the liquid phase, this can enhance the colloidal stability of SLG/FLG. Approaches to achieve noncovalent on-substrate functionalization are also discussed, which can chemically dope graphene. Research efforts to derivatize CNMs are also summarized, as well as novel routes to selectively address defect sites. In dispersion, edges are the most dominant defects and can be covalently modified. This enhances colloidal stability without modifying the graphene basal plane. Basal plane point defects can also be modified, passivated and healed in ultra-high vacuum. The decoration of graphene with metal nanoparticles (NPs) has also received considerable attention, as it allows to exploit synergistic effects between NPs and graphene. Decoration can be either achieved chemically or in the gas phase. All LMs,
|
|
3. |
- Bacon, David J., et al.
(author)
-
Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018 : Technical specifications and performance forecasts
- 2020
-
In: Publications Astronomical Society of Australia. - : Cambridge University Press (CUP). - 1323-3580 .- 1448-6083. ; 37
-
Journal article (peer-reviewed)abstract
- We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from z = 0.35 to 3; and a deep, high-redshift HI IM survey over 100 deg2 from z = 3 to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to z = 3 with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to z = 6. These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.
|
|
4. |
- De Paolis, L., et al.
(author)
-
Kaonic atoms measurement at DA Φ NE : SIDDHARTA and SIDDHARTA-2
- 2019
-
In: Basic Concepts in Nuclear Physics : Theory, Experiments and Applications - 2018 La Rábida International Scientific Meeting on Nuclear Physics - Theory, Experiments and Applications - 2018 La Rábida International Scientific Meeting on Nuclear Physics. - Cham : Springer International Publishing. - 9783030222031 ; 225, s. 191-195
-
Conference paper (peer-reviewed)abstract
- Light kaonic atoms studies provide the unique opportunity to perform experiments equivalent to scattering at threshold, being their atomic binding energies in the keV range. High precision atomic X-rays spectroscopy ensures that the energy shift and broadening of the lowest-lying states of the kaonic atoms, induced by the strong interaction between the kaon and nucleus, can be detected. Kaonic hydrogen and kaonic deuterium are the lightest atomic systems and their study deliver the isospin-dependent kaon-nucleon scattering lengths. The SIDDHARTA collaboration was able to perform the most precise kaonic hydrogen measurement to date, together with an exploratory measurement of kaonic deuterium. The measurement of the kaonic deuterium will be realized in the near future by a major upgrade of SIDDHARTA: SIDDHARTA-2. In this paper an overview of the main results obtained by SIDDHARTA together with the future plans are presented.
|
|
5. |
- Alakukku, Laura, et al.
(author)
-
Maatalouden ympäristötuen vaikuttavuuden seurantatutkimus (MYTVAS 3) : loppuraportti
- 2014
-
Reports (other academic/artistic)abstract
- Since 1995, agri-environmental support partly funded by the EU has formed the core of Finland’s agri-environmental policy. This system has had a variety of impacts on the relationship between agriculture and the environment. Today’s agri-environmental support is one of the packages included in the Rural Development Programme for Mainland Finland (2007–2013/2014), which both in itself and through the underlying EU legislation requires monitoring of the impacts of the measures implemented. The study monitoring the impact of the 2nd Finnish agri-environmental scheme (MYTVAS 3), which ran from 2008 to 2013, forms part of this monitoring. The MYTVAS 3 monitoring study was also financed by the Ministry of the Environment. The monitoring study was carried out by a consortium coordinated by MTT Agrifood Research Finland and including the Finnish Environment Institute (SYKE), the University of Helsinki, the Finnish Game and Fisheries Research Institute and the University of Turku.The purpose of the MYTVAS 3 monitoring study was to find out how agri-environmental support and its various measures have affected the state of the environment in agricultural areas, how agri-environmental support has affected the potential for farming and how agri-environmental support should be developed to increase its impact. The monitoring focused on the impacts of agri-environmental support on the nutrient load from agriculture on the waterways and on biodiversity. When evaluating the findings presented, we should remember that while monitoring data shows that something happened, it does not necessarily explain what caused it. It is not always possible to show that particular developments were a specific outcome of the current agri-environmental support system and the implementation of its measures. The delay between a measure and its observed impact is often long, and the cause-and-effect relationships are complicated and partly unknown. Also, other agricultural policy and fluctuations on the market may affect the state of the agricultural environment directly or indirectly.The monitoring data show that agri-environmental support has not had a detrimental impact on the potential for farming. Despite a slight increase in the incidence of weeds, they do not cause problems of the kind that would require amendments to the content of agri-environmental measures. Carbon levels in the surface stratum of arable land seems to be continuing their slow decline, and there is still need for measures to preserve organic material in the soil.Compliance with the fertilisation limits in the agri-environmental support system would seem to have had very little impact on crop quality. Variations in the weight and protein content per hectolitre and per 1,000 seeds were of the same order between 2006 and 2012 as they were between 1995 and 2005. Crop quantities have also not been noticeably affected by compliance with the fertilisation limits. Average crop yields remained stable between 1986 and 2013, and no clearly different crop years were observed in the 2000s. It is possible, however, that the lower fertilisation levels could have lowered crop potential in the years with advantageous weather conditions in the 2000s and that protein contents have been lower in advantageous years.The monitoring data also show that the nutrient load potential of agriculture, measured by nutrient balances, has decreased continuously for nitrogen and particularly for phosphorus. The decrease in the nutrient load potential is due above all to a decrease in the use of synthetic fertilisers. The decline in nitrogen fertilisation has bottomed out in recent years, and low protein levels measured in high crop yield years show that there is no point in further reducing nitrogen fertilisation. Optimising nitrogen fertilisation according to how advantageous the growing season is and effectively using the soluble nitrogen in cattle manure are key measures in achieving reasonable nitrogen balances and good crop quality despite fluctuations in growing season conditions. New crop variants have been found to make more efficient use of nitrogen than old ones, and thus the introduction of new variants should be promoted. Despite the decrease in the nutrient balances, there are indications that nutrient loads in runoff water from domestic animal production sites are becoming an increasing problem. Indeed, the fundamental problem with the nutrient load from agriculture is the diversification of livestock farming and crop farming, which has made it more difficult to use nutrients appropriately. Therefore attention must be paid to measures that both boost the use of nutrients in manure and reduce the levels of nutrients that end up in manure. Based on nutrient load monitoring in the catchment areas of rivers, the phosphorus load per hectare of cropland has decreased in each programme period, being about 80% of the level of the first period (1995–1999) in the third period (2007–2013). Because of the increase in the area of cropland, the nitrogen load on waterways from agriculture continued to grow during the second programme period (2000–2006) but peaked in the third (2007–2013). A similar trend was found in the nitrogen load per hectare of cropland.The most important threat to biodiversity is caused by the development of landscape structure, typically involving a decrease in the number of open or half-open areas excluded from actual cultivation. The consequence of the clearing of margins and ecological islands located in crop fields, drainage measures aimed at increasing arable land and all rationalisation of cultivated areas is the diminishing of exactly those areas that are the most important from the perspective of the biodiversity of the agricultural environment. However, the measure-specific findings in the monitoring study show that biodiversity benefits have been locally achieved where measures have been implemented on a broad enough scale (biodynamic farming, traditional biotopes, wetlands, buffer zones, green fallow / nature management areas). Particular care should therefore be taken that all cultivated land continues to have a sufficient percentage of non-cultivated areas, whether they be natural meadows, nature management areas, biodiversity strips, buffer zones, filter strips, headlands, ecological islands, etc. Including the rather popular nature management areas as a new voluntary measure under basic measures was a significant contribution to biodiversity.Regarding the rural landscape, it may be noted that by visual inspection the area of cropland has remained largely unchanged, at the level of the landscape as a whole it is far more common for the landscape to become more closed than to become more open. This trend was also observed in the visual inspection of traditional biotopes, even if the openness of the meadows monitored largely remained unchanged.The only measures that directly address the reduction of gaseous emissions in the agri-environmental support system are the longterm grass cultivation on peat fields and special aid agreements for slurry injection in cropland. While other measures have indirectly affected gaseous emissions, the impact of agri-environmental support as a whole on reducing gaseous emissions from agriculture has been negligible. In general, we may conclude that the goals, content and support levels of agri-environmental support measures must be increasingly adapted and customised by region, by type of farming and by farm, because both the state of the agricultural environment and the needs of society differ greatly between different types of rural area.
|
|
6. |
- Ares, Ana M., et al.
(author)
-
Fast determination of intact glucosinolates in broccoli leaf by pressurized liquid extraction and ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry
- 2015
-
In: Food Research International. - : Elsevier BV. - 0963-9969. ; 76, s. 498-505
-
Journal article (peer-reviewed)abstract
- In this study, we investigate for the first time the efficiency of an environmentally sustainable extraction technique (pressurized liquid extraction, PIE) in conjunction with a fast separation technique (ultra-high performance liquid chromatography, UHPLC) coupled to a selective mass spectrometry (MS) detector (quadrupole time-of-flight, qTOF) to extract, separate and quantify fifteen intact-glucosinolates (GLSs) in broccoli leaves. Firstly, we have developed and optimized by means of an experimental design an efficient extraction procedure based on PLE (using ethanol/water as a solvent), giving complete extraction within 15 min; meanwhile, the average analyte recoveries were between 85% and 96% in all cases. Chromatography was performed on a UHPLC BEH Shield RP181.7 mu m 110 angstrom (2.1 x 100 mm) analytical column with a mobile phase composed by formic add in water (0.5%, v/v) and formic acid in acetonitrile (0524 v/v) in gradient elution mode at 03 mL/min, resulted in baseline-separated peaks and a run time of 13 min. The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, precision, and trueness; meanwhile a study of the matrix effect was also performed. A good selectivity, low LODs and LOQs, ranging from 2 to 26 mu g/g, wide linear ranges from LOQ to 2500 mu g/g, and satisfactory precision and trueness with relative standard deviation and relative error values lower than or equal to 9%, were obtained for the studied GLSs. Finally, the proposed method was successfully applied to the analysis of intact-GLSs in fifteen broccoli leaf samples from three different cultivars (Parthenon, Nubia, and Naxos). Nine intact-GLSs were detected in all the varieties, although in different concentrations, which ranged between 14 and 1136 mu g/g, depending on the broccoli cultivar. In addition, the highest total content of GLSs was found in broccoli leaf samples from Parthenon cultivar, being the Naxos cultivar the poorest in GLS content. This study demonstrates the efficiency of PLE as an environmentally sustainable alternative to extract intact-GLS from broccoli leaves, and that UHPLC-qTOE-MS allowed a rapid, selective and sensitive determination of intact-GLSs in this matrix. (C) 2015 Elsevier Ltd. All rights reserved.
|
|
7. |
|
|
8. |
- DeFelipe, Irene, et al.
(author)
-
Reassessing the lithosphere : SeisDARE, an open-access seismic data repository
- 2021
-
In: Earth System Science Data. - : Copernicus Publications. - 1866-3508 .- 1866-3516. ; 13:3, s. 1053-1071
-
Journal article (peer-reviewed)abstract
- Seismic reflection data (normal incidence and wide angle) are unique assets for solid Earth sciences as they provide critical information about the physical properties and structure of the lithosphere as well as about the shallow subsurface for exploration purposes. The resolution of these seismic data is highly appreciated; however they are logistically complex and expensive to acquire, and their geographical coverage is limited. Therefore, it is essential to make the most of the data that have already been acquired. The collation and dissemination of seismic open-access data are then key to promote accurate and innovative research and to enhance new interpretations of legacy data. This work presents the Seismic DAta REpository (SeisDARE), which is, to our knowledge, one of the first comprehensive open-access online databases that stores seismic data registered with a permanent identifier (DOI). The datasets included here are openly accessible online and guarantee the FAIR (findable, accessible, interoperable, reusable) principles of data management, granting the inclusion of each dataset in a statistics referencing database so its impact can be measured. SeisDARE includes seismic data acquired in the last 4 decades in the Iberian Peninsula and Morocco. These areas have attracted the attention of international researchers in the fields of geology and geophysics due to the exceptional outcrops of the Variscan and Alpine orogens and wide foreland basins, the crustal structure of the offshore margins that resulted from a complex plate kinematic evolution, and the vast quantities of natural resources contained within. This database has been built thanks to a network of national and international institutions, promoting a multidisciplinary research and is open for international data exchange and collaborations. As part of this international collaboration, and as a model for inclusion of other global seismic datasets, SeisDARE also hosts seismic data acquired in Hardeman County, Texas (USA), within the COCORP project (Consortium for Continental Reflection Profiling). SeisDARE aims to make easily accessible old and recently acquired seismic data and to establish a framework for future seismic data management plans. SeisDARE is freely available at https://digital.csic.es/handle/10261/101879 (a detailed list of the datasets can be found in Table 1), bringing endless research and teaching opportunities to the scientific, industrial, and educational communities.
|
|
9. |
- Nesti, Cedric, et al.
(author)
-
Hemicolectomy versus appendectomy for patients with appendiceal neuroendocrine tumours 1-2 cm in size : a retrospective, Europe-wide, pooled cohort study
- 2023
-
In: The Lancet Oncology. - : Elsevier. - 1470-2045 .- 1474-5488. ; 24:2, s. 187-194
-
Journal article (peer-reviewed)abstract
- BackgroundAwareness of the potential global overtreatment of patients with appendiceal neuroendocrine tumours (NETs) of 1–2 cm in size by performing oncological resections is increasing, but the rarity of this tumour has impeded clear recommendations to date. We aimed to assess the malignant potential of appendiceal NETs of 1–2 cm in size in patients with or without right-sided hemicolectomy.MethodsIn this retrospective cohort study, we pooled data from 40 hospitals in 15 European countries for patients of any age and Eastern Cooperative Oncology Group performance status with a histopathologically confirmed appendiceal NET of 1–2 cm in size who had a complete resection of the primary tumour between Jan 1, 2000, and Dec 31, 2010. Patients either had an appendectomy only or an appendectomy with oncological right-sided hemicolectomy or ileocecal resection. Predefined primary outcomes were the frequency of distant metastases and tumour-related mortality. Secondary outcomes included the frequency of regional lymph node metastases, the association between regional lymph node metastases and histopathological risk factors, and overall survival with or without right-sided hemicolectomy. Cox proportional hazards regression was used to estimate the relative all-cause mortality hazard associated with right-sided hemicolectomy compared with appendectomy alone. This study is registered with ClinicalTrials.gov, NCT03852693.Findings282 patients with suspected appendiceal tumours were identified, of whom 278 with an appendiceal NET of 1–2 cm in size were included. 163 (59%) had an appendectomy and 115 (41%) had a right-sided hemicolectomy, 110 (40%) were men, 168 (60%) were women, and mean age at initial surgery was 36·0 years (SD 18·2). Median follow-up was 13·0 years (IQR 11·0–15·6). After centralised histopathological review, appendiceal NETs were classified as a possible or probable primary tumour in two (1%) of 278 patients with distant peritoneal metastases and in two (1%) 278 patients with distant metastases in the liver. All metastases were diagnosed synchronously with no tumour-related deaths during follow-up. Regional lymph node metastases were found in 22 (20%) of 112 patients with right-sided hemicolectomy with available data. On the basis of histopathological risk factors, we estimated that 12·8% (95% CI 6·5 –21·1) of patients undergoing appendectomy probably had residual regional lymph node metastases. Overall survival was similar between patients with appendectomy and right-sided hemicolectomy (adjusted hazard ratio 0·88 [95% CI 0·36–2·17]; p=0·71).InterpretationThis study provides evidence that right-sided hemicolectomy is not indicated after complete resection of an appendiceal NET of 1–2 cm in size by appendectomy, that regional lymph node metastases of appendiceal NETs are clinically irrelevant, and that an additional postoperative exclusion of metastases and histopathological evaluation of risk factors is not supported by the presented results. These findings should inform consensus best practice guidelines for this patient cohort.
|
|
10. |
|
|