Electronic origins of photocatalytic activity in d0 metal organic frameworks

Metal-organic frameworks (MOFs) containing d0 metals such as NH2-MIL-125(Ti), NH2-UiO-66(Zr) and NH2-UiO-66(Hf) are among the most studied MOFs for photocatalytic applications. Despite structural similarities, we demonstrate that the electronic properties of these MOFs are markedly different. As revealed by quantum chemistry, EPR measurements and transient absorption spectroscopy, the highest occupied and lowest unoccupied orbitals of NH2-MIL-125(Ti) promote a long lived ligand-to-metal charge transfer upon photoexcitation, making this material suitable for photocatalytic applications. In contrast, in case of UiO materials, the d-orbitals of Zr and Hf, are too low in binding energy and thus cannot overlap with the π* orbital of the ligand, making both frontier orbitals localized at the organic linker. This electronic reconfiguration results in short exciton lifetimes and diminishes photocatalytic performance. These results highlight the importance of orbital contributions at the band edges and delineate future directions in the development of photo-active hybrid solids

Luminescent properties of Bi-doped polycrystalline KAlCl4

We observed an intensive near-infrared luminescence in Bi-doped KAlCl4 polycrystalline material. Luminescence dependence on the excitation wavelength and temperature of the sample was studied. Our experimental results allow asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion which isomorphically substitutes potassium in the crystal. It was also demonstrated that Bi+ luminescence features strongly depend on the local ion surroundings

Enhancing reductive cleavage of aromatic carboxamides

[GRAPHICS] A set of aromatic and especially heteroaromatic N-benzyl carboxamides, derived from naphthalene, pyridine, pyrazine, and quinoline, and the corresponding tert-butyl acylcarbamates have been synthesized and studied by cyclic voltammetry with respect to facilitated reduction. The latter undergo regiospecific cleavage of their C(O)-N bonds under very mild reductive conditions with formation of Boc-protected (benzyl)amine in most cases in nearly quantitative yields, Examples of preparative cleavage by controlled potential electrolysis, activated aluminum, and NaBH4 are given

Short-course antibiotic therapy for critically ill patients treated for postoperative intra-abdominal infection: the DURAPOP randomised clinical trial

PURPOSE: Shortening the duration of antibiotic therapy (ABT) is a key measure in antimicrobial stewardship. The optimal duration of ABT for treatment of postoperative intra-abdominal infections (PIAI) in critically ill patients is unknown. METHODS: A multicentre prospective randomised trial conducted in 21 French intensive care units (ICU) between May 2011 and February 2015 compared the efficacy and safety of 8-day versus 15-day antibiotic therapy in critically ill patients with PIAI. Among 410 eligible patients (adequate source control and ABT on day 0), 249 patients were randomly assigned on day 8 to either stop ABT immediately (n = 126) or to continue ABT until day 15 (n = 123). The primary endpoint was the number of antibiotic-free days between randomisation (day 8) and day 28. Secondary outcomes were death, ICU and hospital length of stay, emergence of multidrug-resistant (MDR) bacteria and reoperation rate, with 45-day follow-up. RESULTS: Patients treated for 8 days had a higher median number of antibiotic-free days than those treated for 15 days (15 [6-20] vs 12 [6-13] days, respectively; P < 0.0001) (Wilcoxon rank difference 4.99 days [95% CI 2.99-6.00; P < 0.0001). Equivalence was established in terms of 45-day mortality (rate difference 0.038, 95% CI - 0.013 to 0.061). Treatments did not differ in terms of ICU and hospital length of stay, emergence of MDR bacteria or reoperation rate, while subsequent drainages between day 8 and day 45 were observed following short-course ABT (P = 0.041). CONCLUSION: Short-course antibiotic therapy in critically ill ICU patients with PIAI reduces antibiotic exposure. Continuation of treatment until day 15 is not associated with any clinical benefit. CLINICALTRIALS. GOV IDENTIFIER: NCT01311765

Utilização da Tecnologia Sulco-camalhão na Produção de Soja e Milho em Terras Baixas do Rio Grande do Sul.

As pesquisas da Embrapa Clima Temperado direcionadas ao cultivo de soja e milho utilizando a tecnologia sulco-camalhão em áreas de terras baixas do Rio Grande do Sul iniciaram há mais de duas décadas. Historicamente, os resultados sempre indicaram benefícios ao desenvolvimento das culturas e aumento de produtividade, independentemente das condições climáticas da safra. Entretanto, a expansão e adoção plena da tecnologia nesse agroecossistema é recente, tendo sido impulsionada pela introdução no mercado nacional de outras duas tecnologias associadas, a sistematização do solo com declividade variada e o uso de politubos para a irrigação, os quais possibilitaram adequar a superfície do terreno com menor movimentação de solo, permitindo uma irrigação precisa e eficiente. Nesse cenário tecnológico, concebeu-se o Projeto Sulco, uma parceria entre Embrapa Clima Temperado, que atua como responsável técnica, e as empresas privadas Centeno & Bergamasco LTDA, Trimble Brasil Soluções, AGCO América do Sul, PIPE Brasil, KLR Kohler Implementos Agrícolas e Pioneer Sementes Brasil. Essa parceria visa o refinamento e a difusão da tecnologia sulco-camalhão para cultivos de sequeiro em terras baixas do Sul do Brasil. Para tanto, tem implantado lavouras-piloto de soja e de milho em várias regiões arrozeiras do Rio Grande do Sul. Todas as iniciativas realizadas têm mostrado que a tecnologia representa uma alternativa acessível e de baixo custo para a produção de soja e milho com elevadas produtividades em terras baixas, garantindo rentabilidade e estabilidade de produção e contribuindo fortemente para a sustentabilidade do sistema produtivo. Esta publicação tem o propósito d

Modelos para sistematização nas terras baixas do Rio Grande do Sul.

Este documento é o resultado do esforço da Embrapa Clima Temperado em atualizar os conhecimentos com relação à aplicação da geotecnologia na sistematização das áreas de terras baixas dos Estados do Sul do País.ODS 6

The optical properties of In2S3 films in the far infrared spectral range

Optical reflection spectra of In2S3 thin films 180 730 nm deposited on glass substrates are measured by infrared spectroscopy using the synchrotron radiation of BESSY II storage ring in the spectral range of 30 8000 cm amp; 8722;1. The aim of the study is to find the influence of different substrate and post annealing temperatures on the electron and phonon systems of In2S3 films deposited on glass. Clear features in the reflectance spectra for the studied films have been found mainly in the phonon excitation range 100 400 cm amp; 8722;1. The experimental dielectric functions amp; 949; amp; 969; of In2S3 films are found to be in good agreement with the calculated ones obtained for In2S3 crystals within the density functional theory. The dielectric functions amp; 949; amp; 969; of the films in the range of 100 400 cm amp; 8722;1 depend substantially on the post annealing temperature. This indicates a transition of the film from the amorphous to the crystalline state. The thorough analysis of the frequency dependence of the reflection coefficient R amp; 969; and optical conductivity amp; 963; amp; 969; in the wavenumber range of 30 130 cm amp; 8722;1 allowed us to reveal the distributed electron states in In2S3 film