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1.
Environ Manage ; 72(4): 818-837, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37286731

RESUMO

Natural resource management (NRM) increasingly relies on communicative measures to enable reframing in intractable conflicts. Reframing occurs when disputants change their perceptions of a conflict situation, and/or their preferences for dealing with it. However, the types of reframing possible, and the conditions under which they can occur, remain unclear. Through an inductive and longitudinal analysis of a mine establishment conflict in northern Sweden this paper explores to what extent, how, and under what conditions reframing can occur in intractable NRM conflicts. The findings reveal the difficulty in achieving consensus-oriented reframing. Despite multiple dispute resolution efforts, the disputants' perceptions and preferences became increasingly polarized. Nonetheless, the results suggest that it is possible to enable reframing to the extent that all disputants can understand and accept each other's different perceptions and positions, i.e., meta-consensus. Meta-consensus hinges on neutral, inclusive, equal, and deliberative intergroup communication. However, the results show that intergroup communication and reframing are significantly informed by institutional and other contextual factors. For example, when implemented within the formal governance system in the investigated case, intergroup communication lagged in quality and did not contribute to meta-consensus. Moreover, the results show that reframing is strongly influenced by the nature of the disputed issues, actors' group commitments, and the governance system's distribution of power to the actors. Based on these findings, it is argued that more efforts should focus on how governance systems can be configurated so that high-quality intergroup communication and meta-consensus can be enabled and inform decision making in intractable NRM conflicts.


Assuntos
Conservação dos Recursos Naturais , Recursos Naturais , Suécia , Comunicação
2.
Phys Chem Chem Phys ; 25(15): 10778-10784, 2023 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-37010316

RESUMO

Here we demonstrate, using pulsed femtosecond laser-induced two-photon oxidation (2PO), a novel method of locally tuning the sensitivity of solution gated graphene field-effect transistors (GFETs) without sacrificing the integrity of the carbon network of chemical vapor deposition (CVD) grown graphene. The achieved sensitivity with 2PO was (25 ± 2) mV pH-1 in BIS-TRIS propane HCl (BTPH) buffer solution, when the oxidation level corresponded to the Raman peak intensity ratio I(D)/I(G) of 3.58. Sensitivity of non-oxidized, residual PMMA contaminated GFETs was 20-22 mV pH-1. The sensitivity decreased initially by 2PO to (19 ± 2) mV pH-1 (I(D)/I(G) = 0.64), presumably due to PMMA residue removal by laser irradiation. 2PO results in local control of functionalization of the CVD-grown graphene with oxygen-containing chemical groups enhancing the performance of the GFET devices. The GFET devices were made HDMI compatible to enable easy coupling with external devices for enhancing their applicability.

3.
ACS Omega ; 8(11): 10225-10234, 2023 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-36969436

RESUMO

The N-fluorenyl-9-methyloxycarbonyl (Fmoc)-protected amino acids have shown high antimicrobial application potential, among which the phenylalanine derivative (Fmoc-F) is the most well-known representative. However, the activity spectrum of Fmoc-F is restricted to Gram-positive bacteria only. The demand for efficient antimicrobial materials expanded research into graphene and its derivatives, although the reported results are somewhat controversial. Herein, we combined graphene oxide (GO) flakes with Fmoc-F amino acid to form Fmoc-F/GO hybrid hydrogel for the first time. We studied the synergistic effect of each component on gelation and assessed the material's bactericidal activity on Gram-negative Escherichia coli (E. coli). GO flakes do not affect Fmoc-F self-assembly per se but modulate the elasticity of the gel and speed up its formation. The hybrid hydrogel affects E. coli survival, initially causing abrupt bacterial death followed by the recovery of the surviving ones due to the inoculum effect (IE). The combination of graphene with amino acids is a step forward in developing antimicrobial gels due to their easy preparation, chemical modification, graphene functionalization, cost-effectiveness, and physicochemical/biological synergy of each component.

4.
Phys Chem Chem Phys ; 25(12): 8725-8733, 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36896827

RESUMO

We report the effects of a laser-oxidized single layer graphene (SLG) surface on the self-assembly of amphiphilic gelator N-fluorenylmethoxycarbonyl-L-phenylalanine (Fmoc-Phe) towards an gel-SLG interface. Laser oxidation modulates the levels of hydrophobicity/hydrophilicity on the SLG surface. Atomic force, scanning electron, helium ion and scattering scanning nearfield optical microscopies (AFM, SEM, HIM, s-SNOM) were employed to assess the effects of surface properties on the secondary and tertiary organization of the formed Fmoc-Phe fibres at the SLG-gel interface. S-SNOM shows sheet-like secondary structures on both hydrophobic/hydrophilic areas of SLG and helical or disordered structures mainly on the hydrophilic oxidized surface. The gel network heterogeneity on pristine graphene was observed at the scale of single fibres by s-SNOM, demonstrating its power as a unique tool to study supramolecular assemblies and interfaces at nanoscale. Our findings underline the sensitivity of assembled structures to surface properties, while our characterization approach is a step forward in assessing surface-gel interfaces for the development of bionic devices.

5.
J Environ Manage ; 315: 115205, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35533469

RESUMO

Deliberative processes are increasingly advocated as means to handle intractable natural resource management (NRM) conflicts. Research shows that disputing actors can deliberate and achieve higher degrees of mutual understanding and working agreements under ideal conditions, but the transferability of these findings to real-world intractable NRM conflicts can be questioned. This paper explores the possibilities of designing and realizing deliberation and its expected outcomes in real-world NRM conflicts. We used recommended design principles to set up deliberative processes in two intractable mining conflicts involving indigenous peoples in Northern Sweden and assessed the actors' communication and outcomes using frame analysis. The results show that the recommended design principles are hard, but not impossible, to fully implement in intractable NRM conflicts. Both conflicts proved difficult to deliberate and resolve in the sense of reaching agreements. However, the findings suggest that deliberation, as well as meta-consensus, or structured disagreement, is possible to achieve in settings with favorable conditions, e.g. good and established inter-group relations prior to the conflict. In the absence of these conditions, where relations were hostile and shaped by historical and institutional injustices, deliberation was not achieved. In both cases, polarization among the participants remained, or increased, in spite of the deliberative activities. The study highlights the importance of understanding deliberation as embedded in place specific historical and institutional contexts which shape both process and outcomes in powerful ways. More efforts should focus on alternative, or complementary, ways to handle intractable NRM conflicts, including how contested experiences of history, institutions and Indigenous rights can be addressed.


Assuntos
Conservação dos Recursos Naturais , Recursos Naturais , Dissidências e Disputas , Humanos , Mineração , Suécia
6.
Internet Interv ; 28: 100531, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35371926

RESUMO

Studies suggest that internet-delivered cognitive behaviour therapy (ICBT) can be effective when treating generalized anxiety disorder (GAD). This pilot factorial design study examined the effects of two types of ICBT (worry-specific and self-tailored treatment), and two support types (scheduled weekly support and support on demand), on measures of worry, anxiety, and depressive symptoms. Participants (N = 85) were randomized into four treatment groups. Post-treatment measures were completed by 76.5% after eight weeks (n = 65). Intention to treat analysis showed significant improvements, with moderate to large within-group effects on the primary outcome measure, Penn State Worry Questionnaire (Cohen's d = 0.77-1.43). Minor to large effects on the secondary measures were found in all groups (Cohen's d = 0.13-1.66). No significant differences in outcome measures were found between the groups. Receiving scheduled support and self-tailored treatment was rated as more positive than receiving support on demand and the worry-specific program. A limitation is the low number of participants. The pilot results suggest that GAD can be treated with both worry-specific and self-tailored treatments, and that ICBT can be supported both with scheduled and support on demand.

7.
Chem Commun (Camb) ; 57(80): 10375-10378, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34541596

RESUMO

A transient organo-gelation system with spatiotemporal dynamic properties is described. Here, the solvent actively controls a complex set of equilibria that underpin the dynamic assembly event. The observed metastability is due to the in situ formation of a secondary solvent, acting as an antagonist against the primary solvent of the organogel.

8.
Sci Rep ; 11(1): 10703, 2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34035337

RESUMO

More than 100 years ago, Robert Millikan demonstrated the quantization of the electron using charged, falling droplets, but the statistical analysis on many falling droplets did not allow a direct visualization of the quantization of charge. Instead of letting the droplets fall, we have used optical levitation to create a single droplet version of Millikan's experiment where the effects of a single electron removal can be observed by the naked eye and measured with a ruler. As we added charges to the levitated droplet, we observed that its equilibrium position jumped vertically in quantized steps. The discrete nature of the droplet's jumps is a direct consequence of the single-electron changes in the charge on the droplet, and therefore clearly demonstrates the quantization of charge. The steps were optically magnified onto a wall and filmed. We anticipate that the video of these single electron additions can become a straightforward demonstration of the quantization of charge for a general audience.

9.
Biotechnol Biofuels ; 14(1): 41, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33568224

RESUMO

BACKGROUND: Baker's yeast is a widely used eukaryotic cell factory, producing a diverse range of compounds including biofuels and fine chemicals. The use of lignocellulose as feedstock offers the opportunity to run these processes in an environmentally sustainable way. However, the required hydrolysis pretreatment of lignocellulosic material releases toxic compounds that hamper yeast growth and consequently productivity. RESULTS: Here, we employ CRISPR interference in S. cerevisiae to identify genes modulating fermentative growth in plant hydrolysate and in presence of lignocellulosic toxins. We find that at least one-third of hydrolysate-associated gene functions are explained by effects of known toxic compounds, such as the decreased growth of YAP1 or HAA1, or increased growth of DOT6 knock-down strains in hydrolysate. CONCLUSION: Our study confirms previously known genetic elements and uncovers new targets towards designing more robust yeast strains for the utilization of lignocellulose hydrolysate as sustainable feedstock, and, more broadly, paves the way for applying CRISPRi screens to improve industrial fermentation processes.

10.
Nanoscale Adv ; 3(5): 1431-1442, 2021 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-36132861

RESUMO

Properties of graphene, such as electrical conduction and rigidity can be tuned by introducing local strain or defects into its lattice. We used optical forging, a direct laser writing method, under an inert gas atmosphere, to produce complex 3D patterns of single layer graphene. We observed bulging of graphene out of the plane due to defect induced lattice expansion. By applying low peak fluences, we obtained a 3D-shaped graphene surface without either ablating it or deforming the underlying Si/SiO2 substrate. We used micromachining theory to estimate the single-pulse modification threshold fluence of graphene, which was 8.3 mJ cm-2, being an order of magnitude lower than the threshold for ablation. The control of exposure parameters allowed the preparation of blisters with various topographies. The optically forged structures were studied with atomic force microscopy and Raman spectroscopy. Optically forged blisters act as building blocks in the formation of more complex structures. We found a simple geometric rule that helps to predict the shape of complex patterns which are created by the overlapping multiple exposures. Optical forging enables writing of extended patterns with diffraction unlimited features, which makes this method promising in the production of nanodevices with locally induced surface modifications.

11.
Nanoscale Adv ; 3(7): 2065-2074, 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-36133099

RESUMO

An approach for controlled protein immobilization on laser-induced two-photon (2P) oxidation patterned graphene oxide (GO) surfaces is described. Selected proteins, horseradish peroxidase (HRP) and biotinylated bovine serum albumin (b-BSA) were successfully immobilized on oxidized graphene surfaces, via non-covalent interactions, by immersion of graphene-coated microchips in the protein solution. The effects of laser pulse energy, irradiation time, protein concentration and duration of incubation on the topography of immobilized proteins and consequent defects upon the lattice of graphene were systemically studied by atomic force microscopy (AFM) and Raman spectroscopy. AFM and fluorescence microscopy confirmed the selective aggregation of protein molecules towards the irradiated areas. In addition, the attachment of b-BSA was detected by a reaction with fluorescently labelled avidin-fluorescein isothiocyanate (Av-FITC). In contrast to chemically oxidized graphene, laser-induced oxidation introduces the capability for localization on oxidized areas and tunability of the levels of oxidation, resulting in controlled guidance of proteins by light over graphene surfaces and progressing towards graphene microchips suitable for biomedical applications.

12.
Sci Rep ; 10(1): 5126, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198378

RESUMO

The present study evaluates the role of graphene oxide's (GO's) peroxidase-like and inherent/carbocatalytic properties in oxidising silver nitrate (AgNO3) to create graphene nanocomposites with silver nanoparticles (GO/Ag nanocomposite). Activation of peroxidase-like catalytic function of GO required hydrogen peroxide (H2O2) and ammonia (NH3) in pH 4.0 disodium hydrogen phosphate (Na2HPO4). Carbocatalytic abilities of GO were triggered in pH 4.0 deionised distilled water (ddH2O). Transmission electron microscope (TEM), scanning electron microscope (SEM), cyclic voltammetry (CV) and UV-Vis spectroscopy aided in qualitatively and quantitatively assessing GO/Ag nanocomposites. TEM and SEM analysis demonstrated the successful use of GO's peroxidase-like and carbocatalytic properties to produce GO/Ag nanocomposite. UV-Vis analysis indicated a higher yield in optical density values for GO/Ag nanocomposites created using GO's carbocatalytic ability rather than its peroxidase-like counterpart. Additionally, CV demonstrated that GO/Ag nanocomposite fabricated here is a product of an irreversible electrochemical reaction. Our study outcomes show new opportunities for GO as a standalone catalyst in biosensing. We demonstrate a sustainable approach to obtain graphene nanocomposites exclusive of harmful chemicals or physical methods.

14.
J Vis Exp ; (143)2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30688310

RESUMO

The work presents an experiment that allows the study of many fundamental physical processes, such as photon pressure, diffraction of light or the motion of charged particles in electrical fields. In this experiment, a focused laser beam pointing upwards levitate liquid droplets. The droplets are levitated by the photon pressure of the focused laser beam which balances the gravitational force. The diffraction pattern created when illuminated with laser light can help measure the size of a trapped droplet. The charge of the trapped droplet can be determined by studying its motion when a vertically directed electrical field is applied. There are several reasons motivating this experiment to be remotely controlled. The investments required for the setup exceeds the amount normally available in undergraduate teaching laboratories. The experiment requires a laser of Class 4, which is harmful to both skin and eyes and the experiment uses voltages that are harmful.


Assuntos
Laboratórios , Óptica e Fotônica/métodos , Eletricidade , Eletrodos , Lasers , Interface Usuário-Computador
15.
J Phys Chem Lett ; 9(21): 6179-6184, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30380894

RESUMO

In nanofabrication, just as in any other craft, the scale of spatial details is limited by the dimensions of the tool at hand. For example, the smallest details of direct laser writing with far-field light are set by the diffraction limit, which is approximately half of the used wavelength. In this work, we overcome this universal assertion by optically forging graphene ripples that show features with dimensions unlimited by diffraction. Thin sheet elasticity simulations suggest that the scaled-down ripples originate from the interplay between substrate adhesion, in-plane strain, and circular symmetry. The optical forging technique thus offers an accurate way to modify and shape 2D materials and facilitates the creation of controllable nanostructures for plasmonics, resonators, and nano-optics.

16.
J Environ Manage ; 218: 402-415, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29704835

RESUMO

Natural resource (NR) exploitation often gives rise to conflict. While most actors intend to manage collectively used places and their NRs sustainably, they may disagree about what this entails. This article accordingly explores the origin of NR conflicts by analysing them in terms of competing pathways to sustainability. By comparing conflicts over mine establishments in three places in northern Sweden, we specifically explore the role of place-based perceptions and experiences. The results indicate that the investigated conflicts go far beyond the question of metals and mines. The differences between pathways supporting mine establishment and those opposing it refer to fundamental ideas about human-nature relationships and sustainable development (SD). The study suggests that place-related parameters affect local interpretations of SD and mobilisation in ways that explain why resistance and conflict exist in some places but not others. A broader understanding of a particular conflict and its specific place-based trajectory may help uncover complex underlying reasons. However, our comparative analysis also demonstrates that mining conflicts in different places share certain characteristics. Consequently, a site-specific focus ought to be combined with attempts to compare, or map, conflicts at a larger scale to improve our understanding of when and how conflicts evolve. By addressing the underlying causes and origins of contestation, this study generates knowledge needed to address NR management conflicts effectively and legitimately.


Assuntos
Conservação dos Recursos Naturais , Mineração , Humanos , Suécia
17.
Nano Lett ; 17(10): 6469-6474, 2017 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-28926715

RESUMO

Atomically thin materials, such as graphene, are the ultimate building blocks for nanoscale devices. But although their synthesis and handling today are routine, all efforts thus far have been restricted to flat natural geometries, since the means to control their three-dimensional (3D) morphology has remained elusive. Here we show that, just as a blacksmith uses a hammer to forge a metal sheet into 3D shapes, a pulsed laser beam can forge a graphene sheet into controlled 3D shapes in the nanoscale. The forging mechanism is based on laser-induced local expansion of graphene, as confirmed by computer simulations using thin sheet elasticity theory.

18.
Anticancer Res ; 37(4): 1825-1830, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28373447

RESUMO

AIM: To quantify the impact of decreased margins for two treatment techniques, three-dimensional conformal radiotherapy (3D-CRT) and volumetric-modulated arc therapy (VMAT), on local control in curative treatment of prostate cancer. MATERIALS AND METHODS: The planning target volume (PTV) margins were decreased in steps of 1 mm from 10 to 1 mm. Treatment plans using 3D-CRT and VMAT technique were produced for all margin sizes and the dose to the neuro vascular bundles (NVB), that was not included in the PTV, was investigated. RESULTS: Due to the more conformal dose delivery using VMAT, the dose to the NVB decreased more rapidly by VMAT compared to the 3D-CRT plans. The dose difference was significant for margins from 1-7 mm. CONCLUSION: One should be very cautious before clinical routines are changed, bearing in mind whether the change means more conformal treatment technique, smaller margins or target segmentation in different imaging modalities.


Assuntos
Adenocarcinoma/radioterapia , Recidiva Local de Neoplasia/diagnóstico , Neovascularização Patológica/etiologia , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/efeitos adversos , Radioterapia de Intensidade Modulada/efeitos adversos , Adenocarcinoma/patologia , Humanos , Masculino , Gradação de Tumores , Recidiva Local de Neoplasia/etiologia , Prognóstico , Neoplasias da Próstata/patologia , Dosagem Radioterapêutica
19.
Phys Chem Chem Phys ; 17(1): 209-16, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25381806

RESUMO

Photo-oxidation of individual, air-suspended single walled carbon nanotubes (SWCNTs) is studied by femtosecond laser spectroscopy and imaging. Individual SWCNTs are imaged by four wave mixing (FWM) microscopy under an inert gas (Ar or N2) atmosphere. When imaging is performed in an ambient air atmosphere, the decay of the FWM signal takes place. Electron microscopy shows that SWCNTs are not destroyed and the process is attributed to photoinduced oxidation reactions which proceed via a non-linear excitation mechanism, when irradiation is performed with ∼30 fs pulses in the visible spectral region (500-600 nm). Photo-oxidation can be localized in specific regions of SWCNTs within optical resolution (∼300 nm). The effect of photo-oxidation on Raman spectra was studied by irradiating a local spot on an individual SWCNT and comparing the spectra of irradiated and non-irradiated regions of the same tube. It is shown at an individual nanotube level that oxidation leads to a decrease of the intensity of the Raman signal and an upshift of the G-band.

20.
Nanoscale ; 7(7): 2851-5, 2015 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-25492105

RESUMO

We demonstrate a simple all-optical patterning method for graphene, based on laser induced two-photon oxidation. By tuning the intensity and dose of irradiation, the level of oxidation is controlled, the band gap is introduced and electrical and optical properties are continuously tuned. Complex patterning is performed for air-suspended monolayer graphene and for graphene on substrates. The presented concept allows development of all-graphene electronic and optoelectronic devices with an all-optical method.

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