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1.
Environ Manage ; 62(1): 45-57, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29785612

RESUMO

A growing world population and rapid expansion of cities increase the pressure on basic resources such as water, food and energy. To safeguard the provision of these resources, restoration and sustainable management of landscapes is pivotal, including sustainable forest and water management. Sustainable forest management includes forest conservation, restoration, forestry and agroforestry practices. Interlinkages between forests and water are fundamental to moderate water budgets, stabilize runoff, reduce erosion and improve biodiversity and water quality. Sweden has gained substantial experience in sustainable forest management in the past century. Through significant restoration efforts, a largely depleted Swedish forest has transformed into a well-managed production forest within a century, leading to sustainable economic growth through the provision of forest products. More recently, ecosystem services are also included in management decisions. Such a transformation depends on broad stakeholder dialog, combined with an enabling institutional and policy environment. Based on seminars and workshops with a wide range of key stakeholders managing Sweden's forests and waters, this article draws lessons from the history of forest management in Sweden. These lessons are particularly relevant for countries in the Global South that currently experience similar challenges in forest and landscape management. The authors argue that an integrated landscape approach involving a broad array of sectors and stakeholders is needed to achieve sustainable forest and water management. Sustainable landscape management-integrating water, agriculture and forests-is imperative to achieving resilient socio-economic systems and landscapes.


Assuntos
Conservação dos Recursos Naturais/métodos , Política Ambiental/tendências , Agricultura Florestal/organização & administração , Florestas , Árvores/crescimento & desenvolvimento , Qualidade da Água/normas , Agricultura/organização & administração , Biodiversidade , Agricultura Florestal/tendências , Crescimento Demográfico , Suécia , Árvores/classificação , Urbanização
3.
Psychiatr Q ; 86(3): 407-17, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25597030

RESUMO

Many individuals treated for depression suffer relapse or recurrence after treatment. Known risk factors include number of previous depressive episodes and residual symptoms after treatment. Both relapse/recurrence rates and predictors of relapse/recurrence, however, may differ between various settings. To perform a naturalistic evaluation of the sustained effectiveness of treatment for adult clinical depression in a psychiatric out-patient setting and to examine psychosocial and clinical predictors of relapse/recurrence. 51 individuals, who were successfully treated/discharged from psychiatric care 12 months prior, were assessed regarding current depressive status and regarding relapse and recurrence. Logistic regression was used to assess the predictive impact of the variables measured. At the 12-month follow-up, 26% of the participants were in complete remission, 45% were in partial remission, and 29% were clinically depressed. In 1 year, 61% suffered a new depressive episode. Having a greater number of previous episodes and having no partner significantly increased the risk of relapse or recurrence. A high prevalence of depression and partially remitted depression is reported at 12-month follow up, and a large proportion of the sample would likely benefit from active treatment. Relapse/recurrence rates are higher in this study than in many other studies, and it may be hypothesized that they are generally higher in psychiatric settings than in primary care. If so, this would indicate the need for a different treatment strategy in the psychiatric care of depression, with emphasis on long-term management of depression.


Assuntos
Depressão/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Depressão/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
4.
Inorg Chem ; 52(9): 5128-37, 2013 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-23597274

RESUMO

A series of homoleptic bis(tridentate) [Ru(L)2](2+) (1, 3) and heteroleptic [Ru(L)(dqp)](2+) complexes (2, 4) [L = dqxp (1, 2) or dNinp (3, 4); dqxp = 2,6-di(quinoxalin-5-yl)pyridine, dNinp = 2,6-di(N-7-azaindol-1-yl)pyridine, dqp = 2,6-di(quinolin-8-yl)pyridine] was prepared and in the case of 2 and 4 structurally characterized. The presence of dqxp and dNinp in 1-4 result in anodically shifted oxidation potentials of the Ru(3+/2+) couple compared to that of the archetypical [Ru(dqp)2](2+) (5), most pronounced for [Ru(dqxp)2](2+) (1) with a shift of +470 mV. These experimental findings are corroborated by DFT calculations, which show contributions to the complexes' HOMOs by the polypyridine ligands, thereby stabilizing the HOMOs and impeding electron extraction. Complex 3 exhibits an unusual electronic absorption spectrum with its lowest energy maximum at 382 nm. TD-DFT calculations suggest that this high-energy transition is caused by a localization of the LUMO on the central pyridine fragments of the dNinp ligands in 3, leaving the lateral azaindole units merely spectator fragments. The opposite is the case in 1, where the LUMO experiences large stabilization by the lateral quinoxalines. Owing to the differences in LUMO energies, the complexes' reduction potentials differ by about 900 mV [E(1/2)(1(2+/1+)) = -1.17 V, E(c,p)(3(2+/1+)) = -2.06 V vs Fc(+/0)]. As complexes 1-4 exhibit similar excited state energies of around 1.80 V, the variations of the lateral heterocycles allow the tuning of the complexes' excited state oxidation strengths over a range of 900 mV. Complex 1 is the strongest excited state oxidant of the series, exceeding even [Ru(bpy)3](2+) by more than 200 mV. At room temperature, complex 3 is nonemissive, whereas complexes 1, 2, and 4 exhibit excited state lifetimes of 255, 120, and 1570 ns, respectively. The excited state lifetimes are thus somewhat shortened compared to that of 5 (3000 ns) but still acceptable to qualify the complexes as photosensitizers in light-induced charge-transfer schemes, especially for those that require high oxidative power.

5.
Opt Express ; 20(3): 3043-56, 2012 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-22330541

RESUMO

A novel technique, designated dual imaging and modeling evaluation (DIME), for evaluating single-laser shot fluorescence lifetimes is presented. The technique is experimentally verified in a generic gas mixing experiment to provide a clear demonstration of the rapidness and sensitivity of the detector scheme. Single-laser shot fluorescence lifetimes of roughly 800 ps with a standard deviation of ~120 ps were determined. These results were compared to streak camera measurements. Furthermore, a general fluorescence lifetime determination algorithm is proposed. The evaluation algorithm has an analytic, linear relationship between the fluorescence lifetime and detector signal ratio. In combination with the DIME detector scheme, it is a faster, more accurate and more sensitive approach for rapid fluorescence lifetime imaging than previously proposed techniques. Monte Carlo simulations were conducted to analyze the sensitivity of the detector scheme as well as to compare the proposed evaluation algorithm to previously presented rapid lifetime determination algorithms.


Assuntos
Algoritmos , Aumento da Imagem/instrumentação , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/instrumentação , Interpretação de Imagem Assistida por Computador/métodos , Lasers , Microscopia de Fluorescência/instrumentação , Desenho de Equipamento , Análise de Falha de Equipamento
6.
J Am Chem Soc ; 133(34): 13224-7, 2011 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-21812404

RESUMO

Proton-coupled electron transfer (PCET) was examined in a series of biomimetic, covalently linked Ru(II)(bpy)(3)-tyrosine complexes where the phenolic proton was H-bonded to an internal base (a benzimidazyl or pyridyl group). Photooxidation in laser flash/quench experiments generated the Ru(III) species, which triggered long-range electron transfer from the tyrosine group concerted with short-range proton transfer to the base. The results give an experimental demonstration of the strong dependence of the rate constant and kinetic isotope effect for this intramolecular PCET reaction on the effective proton transfer distance, as reflected by the experimentally determined proton donor-acceptor distance.


Assuntos
2,2'-Dipiridil/análogos & derivados , Prótons , Tirosina/química , 2,2'-Dipiridil/química , Complexos de Coordenação , Transporte de Elétrons , Elétrons , Fenóis/química
7.
Acc Chem Res ; 42(12): 1899-909, 2009 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-19757805

RESUMO

Photosynthesis is performed by a multitude of organisms, but in nearly all cases, it is variations on a common theme: absorption of light followed by energy transfer to a reaction center where charge separation takes place. This initial form of chemical energy is stabilized by the biosynthesis of carbohydrates. To produce these energy-rich products, a substrate is needed that feeds in reductive equivalents. When photosynthetic microorganisms learned to use water as a substrate some 2 billion years ago, a fundamental barrier against unlimited use of solar energy was overcome. The possibility of solar energy use has inspired researchers to construct artificial photosynthetic systems that show analogy to parts of the intricate molecular machinery of photosynthesis. Recent years have seen a reorientation of efforts toward creating integrated light-to-fuel systems that can use solar energy for direct synthesis of energy-rich compounds, so-called solar fuels. Sustainable production of solar fuels is a long awaited development that promises extensive solar energy use combined with long-term storage. The stoichiometry of water splitting into molecular oxygen, protons, and electrons is deceptively simple; achieving it by chemical catalysis has proven remarkably difficult. The reaction center Photosystem II couples light-induced charge separation to an efficient molecular water-splitting catalyst, a Mn(4)Ca complex, and is thus an important template for biomimetic chemistry. In our aims to design biomimetic manganese complexes for light-driven water oxidation, we link photosensitizers and charge-separation motifs to potential catalysts in supramolecular assemblies. In photosynthesis, production of carbohydrates demands the delivery of multiple reducing equivalents to CO(2). In contrast, the two-electron reduction of protons to molecular hydrogen is much less demanding. Virtually all microorganisms have enzymes called hydrogenases that convert protons to hydrogen, many of them with good catalytic efficiency. The catalytic sites of hydrogenases are now the center of attention of biomimetic efforts, providing prospects for catalytic hydrogen production with inexpensive metals. Thus, we might complete the water-to-fuel conversion: light + 2H(2)O --> 2H(2) + O(2). This reaction formula is to some extent already elegantly fulfilled by cyanobacteria and green algae, water-splitting photosynthetic microorganisms that under certain conditions also can produce hydrogen. An alternative route to hydrogen from solar energy is therefore to engineer these organisms to produce hydrogen more efficiently. This Account describes our original approach to combine research in these two fields: mimicking structural and functional principles of both Photosystem II and hydrogenases by synthetic chemistry and engineering cyanobacteria to become better hydrogen producers and ultimately developing new routes toward synthetic biology.


Assuntos
Biomimética/métodos , Cianobactérias/metabolismo , Energia Solar , Clorófitas/metabolismo , Transporte de Elétrons , Hidrogênio/química , Hidrogênio/metabolismo , Hidrogenase/metabolismo , Ferro/química , Manganês/química , Nanopartículas/química , Oxirredução , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Rutênio/química , Titânio/química , Água/química , Água/metabolismo
8.
Chemistry ; 16(9): 2830-42, 2010 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-20087914

RESUMO

The first examples of rodlike donor-photosensitizer-acceptor arrays based on bis-2,6-di(quinolin-8-yl)pyridine Ru(II) complexes 1a and 3a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time-resolved absorption spectroscopy reveals long-lived, photoinduced charge-separated states (tau(CSS) (1a)=140 ns, tau(CSS) (3a)=200 ns) formed by stepwise electron transfer. The overall yields of charge separation (> or = 50% for complex 1a and > or = 95% for complex 3a) are unprecedented for bis-tridentate Ru(II) polypyridyl complexes. This is attributed to the long-lived excited state of the [Ru(dqp)(2)](2+) complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.

9.
Inorg Chem ; 49(2): 374-6, 2010 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-20000405

RESUMO

Cyclometalated bis-tridentate ruthenium(II) complexes incorporating 2,6-diquinolin-8-ylpyridine ligands and exhibiting broad visible absorptions are described. A [Ru(N(wedge)N(wedge)N)(N(wedge)C(wedge)N)](+) complex based only on ligands with expanded bite angles has a metal-to-ligand charge-transfer excited-state lifetime of 16 ns, which is attributed to a strong ligand field and therefore reduced deactivation via metal-centered states.

10.
Chemistry ; 15(5): 1195-204, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19072945

RESUMO

Electron-transfer-induced linkage isomerization was investigated in a series of bis-tridentate Ru polypyridyl complexes [Ru(L-X-OH)(Y-tpy)](2+) with ambidentate ligand L-X-OH=bpy-C(R)(OH)-py (bpy=2,2'-bipyridine; py=pyridine; R=H, Me, Ph, or tBu) and spectator ligand Y-tpy (tpy=2,2':6',2''-terpyridine; Y=p-tolyl, p-PhCO(2)Me, Cl, OEt, N-pyrrolidine). The ligand-bound ambidentate motif switches reversibly between N and O coordination in the Ru(II) and Ru(III) state, respectively. The potentials of the Ru(III/II) couple differ by about 0.5 V between the isomers, and this results in a bistable electrochemical response of the molecular switches. The effects of structural modifications in form of substituents on the linking carbon atom of the ambidentate ligand and on the central pyridine moiety of the spectator ligand were investigated by electrochemical and computational methods. Differences in isomerization behavior span six orders of magnitude in rate constants and two orders of magnitude in equilibrium constants. The results can be interpreted in terms of steric and electronic substituent effects and their influence on rotational barriers, ligation geometry, and electron deficiency of the metal center.

11.
Chem Commun (Camb) ; (23): 3425-7, 2009 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-19503892

RESUMO

An electrochemically bistable ruthenium polypyridyl complex was immobilised on platinum electrodes via amide condensation with an amine-terminated self-assembled thiol monolayer and underwent rapid electron transfer-induced linkage isomerism.

12.
Inorg Chem ; 48(7): 3228-38, 2009 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-19254036

RESUMO

Synthetic routes to meridional bistridentate ruthenium(II) complexes based on 2,6-di(quinolin-8-yl)pyridyl (dqp) ligands have been investigated. Microwave-assisted synthesis at 200 degrees C allowed the high yield (49-87%) preparation of homoleptic meridional [Ru(dqp)(2)](2+)-based complexes containing inert functional groups. Applying this protocol for the synthesis of mer-[Ru(dqp)(2)](2+) (mer-1) but lowering the temperature to 180 degrees C and shorter reaction times revealed the formation of the facial isomers cis,fac-1 and trans,fac-1 (56% and 12% yields, respectively). The facial isomers were characterized by NMR spectroscopy and X-ray diffraction analysis. In a stepwise protocol, the reaction of Ru(dqp)Cl(3) or Ru(dqp)(L)Cl(2) (L = MeCN or DMSO) and a second equivalent dqp gave mer-1 in 12-26% yields and N(5)Cl-coordinated [Ru(dqp)(2)Cl](+) (28-46%). [Ru(dqp(2))Cl](+) was photochemically, or thermally in the presence of Ag(I), converted to mer-1. By using mer-[Ru(dqp)(MeCN)(3)] (2+), which was crystallographically characterized, a wide range of homo- and heteroleptic meridional [Ru(dqp)(2)](2+)-based complexes was synthesized in up to 77% yield. The synthetic utility of meridional [Ru(dqp)(2)](2+)-based complexes as building blocks was demonstrated by palladium-catalyzed homocoupling of mer-[Ru(dqp)(dqpPhBr)](2+) to form a dinuclear complex. The redox and photophysical properties of the meridional complexes are discussed.

13.
Internet Interv ; 17: 100247, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31249791

RESUMO

Depression is one of the most common health problems worldwide but is often undertreated. Internet-delivered cognitive behavioral therapy (ICBT) appears to be an effective treatment option, with the potential to reach a larger proportion of individuals suffering from depression. While many studies have examined the efficacy of ICBT for depression in randomized controlled trials, fewer have focused on the effectiveness of ICBT when used as an integral part of routine health care. In this study the effectiveness of an 8-week ICBT program was examined when delivered in a routine psychiatric setting. A total of 108 patients were referred and 54 were then included and randomized to either ICBT or a waitlist control condition. The sample had a lower education level and a higher proportion of individuals were on sick leave than comparable previous efficacy trials of ICBT for depression conducted in Sweden. Measures assessing depression, anxiety and psychiatric symptoms were administered before and after treatment, follow up was performed at 6- and 12 months after treatment had ended. ICBT resulted in significant reductions of depressive symptoms in the treatment group when compared to a waitlist control group with a large effect size (Cohen's d = 1.6). Treatment gains were maintained at 6- and 12 months after the treatment had ended. In terms of clinical significance, 58% of the sample had improved or recovered after treatment. The study was small, and patients received general psychiatric care after the ICBT treatment had ended which limits the implications. We conclude that ICBT appears to be an effective treatment for depression when delivered as an integral part of routine psychiatric care.

14.
J Am Chem Soc ; 130(29): 9194-5, 2008 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-18582051

RESUMO

Proton coupled electron transfer (PCET) from tyrosine covalently linked to Ru(bpy)32+ has been studied with laser flash-quench techniques. Two new complexes with internal hydrogen bonding bases to the phenolic proton have been synthesized. Depending on the hydrogen bonding and protonation situation the rate constant of PCET spanned over 5 orders of magnitude and revealed a systematic dependence on pH. This resulted in a previously predicted "rate ladder" scheme: (i) pH dependent concerted electron-proton transfer (CEP) with deprotonation to bulk water, giving low PCET rates, (ii) pH independent CEP with deprotonation to the internal base, giving intermediate PCET rates, and (iii) pure electron transfer from tyrosinate, giving high rates. This behavior is reminiscent of Yz oxidation in Mn-depleted and native photosystem II. The study also revealed important differences in rates between phenols with strong and weak hydrogen bonds, and for the latter a hydrogen bond-gated PCET was observed.


Assuntos
Tirosina/química , Água/química , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/química , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Compostos Organometálicos/química , Oxirredução , Fenóis/química , Fenilacetatos/química , Prótons , Rutênio/química , Salicilatos/química , Soluções
15.
J Am Chem Soc ; 130(1): 26-7, 2008 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-18076179

RESUMO

The dinuclear RuII-PdII complex shows efficient H2 production in the presence of triethylamine as a sacrificial electron and proton donor under visible light irradiation. XPS and TEM analyses reveal that photoreduction of PdII to Pd0 causes dissociation of Pd from the complex to form colloids that are suggested to be the actual catalyst for H2 production.

16.
J Am Chem Soc ; 130(46): 15533-42, 2008 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-19006410

RESUMO

A series of bistridentate ruthenium(II) polypyridyl-type complexes based on the novel 2,6-di(quinolin-8-yl)pyridine (dqp) ligand have been synthesized and their photophysical properties have been studied. The complexes are amenable to substitution in the 4-position of the central pyridine with conserved quasi-C2v symmetry, which allows for extension to isomer-free, rod-like molecular arrays for vectorial control of electron and energy transfer. DFT calculations performed on the parent [Ru(dqp) 2](2+) complex (1) predicted a more octahedral structure than in the typical bistridentate complex [Ru(tpy)2](2+) (tpy is 2,2':6',2"-terpyridine) thanks to the larger ligand bite angle, which was confirmed by X-ray crystallography. A strong visible absorption band, with a maximum at 491 nm was assigned to a metal-to-ligand charge transfer (MLCT) transition, based on time-dependent DFT calculations. 1 shows room temperature emission (Phi = 0.02) from its lowest excited ((3)MLCT) state that has a very long lifetime (tau = 3 micros). The long lifetime is due to a stronger ligand field, because of the more octahedral structure, which makes the often dominant activated decay via short-lived metal-centered states insignificant also at elevated temperatures. A series of complexes based on dqp with electron donating and/or accepting substituents in the 4-position of the pyridine was prepared and the properties were compared to those of 1. An unprecedented (3)MLCT state lifetime of 5.5 micros was demonstrated for the homoleptic complex based on dqpCO2Et. The favorable photosensitizer properties of 1, such as a high extinction coefficient, high excited-state energy and long lifetime, and tunable redox potentials, are maintained upon substitution. In addition, the parent complex 1 is shown to be remarkably photostable and displays a high reactivity in light-induced electron and energy transfer reactions with typical energy and electron acceptors and donors: methylviologen, tetrathiofulvalene, and 9,10-diphenylanthracene. This new class of complexes constitutes a promising starting point for the construction of linear, rod-like molecular arrays for photosensitized reactions and applications in artificial photosynthesis and molecular electronics.

17.
Inorg Chem ; 47(13): 5531-3, 2008 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-18517194

RESUMO

Two alternative Ru 2 (2+/3+) mixed-valence states are formed in the first dinuclear Ru complex with a ligand-bound ambidentate motif. The hysteretic electrochemical response follows a double-square scheme where the structure of the mixed-valence state depends on the previous isovalent state. The Ru (3+) state of the pyrrolidine-substituted bisterpyridine unit is characterized by intense ligand-to-metal charge-transfer absorptions that provide a distinctive signature of the corresponding mixed-valence state.

19.
Chem Commun (Camb) ; (12): 1578-80, 2005 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-15770265

RESUMO

Rapid and complete switching between the N6 and the N5O donor set induced by changing the metal oxidation state has been observed for a new structural motif based on a ruthenium(II) polypyridyl complex.

20.
Chem Commun (Camb) ; (2): 194-5, 2004 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-14737545

RESUMO

Long-lived charge-separated states in the ns to [micro sign]s range were observed upon laser flash excitation of a donor-chromophore-acceptor triad based on tris(bipyridine) ruthenium(ii) as photo-sensitizer, naphthalene diimide as acceptor, and a hydrogen bonded phenol as donor.

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