Supergiant Barocaloric Effects in Acetoxy Silicone Rubber over a Wide Temperature Range: Great Potential for Solid-state Cooling

Solid-state cooling based on caloric effects is considered a viable alternative to replace the conventional vapor-compression refrigeration systems. Regarding barocaloric materials, recent results show that elastomers are promising candidates for cooling applications around room-temperature. In the present paper, we report supergiant barocaloric effects observed in acetoxy silicone rubber - a very popular, low-cost and environmentally friendly elastomer. Huge values of adiabatic temperature change and reversible isothermal entropy change were obtained upon moderate applied pressures and relatively low strains. These huge barocaloric changes are associated both to the polymer chains rearrangements induced by confined compression and to the first-order structural transition. The results are comparable to the best barocaloric materials reported so far, opening encouraging prospects for the application of elastomers in near future solid-state cooling devices.Comment: 19 pages, 7 figures, 2 table

Laboratory Animal Models for Brucellosis Research

Brucellosis is a chronic infectious disease caused by Brucella spp., a Gram-negative facultative intracellular pathogen that affects humans and animals, leading to significant impact on public health and animal industry. Human brucellosis is considered the most prevalent bacterial zoonosis in the world and is characterized by fever, weight loss, depression, hepato/splenomegaly, osteoarticular, and genital infections. Relevant aspects of Brucella pathogenesis have been intensively investigated in culture cells and animal models. The mouse is the animal model more commonly used to study chronic infection caused by Brucella. This model is most frequently used to investigate specific pathogenic factors of Brucella spp., to characterize the host immune response, and to evaluate therapeutics and vaccines. Other animal species have been used as models for brucellosis including rats, guinea pigs, and monkeys. This paper discusses the murine and other laboratory animal models for human and animal brucellosis

Probing the interference between non-linear, axionic and space-time-anisotropy effects in the QED vacuum

We pursue the investigation of a generic non-linear extension of axionic electrodynamics (ED) in a Carroll-Field-Jackiw (CFJ) scenario that implements Lorentz-symmetry violation (LSV). The model consists of an arbitrary non-linear ED action coupled to the axion field in presence of an anisotropy four-vector that realizes the breaking of Lorentz symmetry under the particle point of view. The non-linear electromagnetic field is expanded around a constant and uniform magnetic background up to second order in the propagating photon field. Our attention is the study of the material properties of the vacuum in the particular case of a space-like CFJ $4$-vector. The dispersion relations associated to the plane wave solutions are explicitly worked out in two situations: the magnetic background perpendicular and parallel to the wave direction. We extend these results to consider the analysis of the birefringence phenomenon in presence of non-linearity, the axion and the LSV manifested through the spatial anisotropy. Three specific proposals of non-linear ED are contemplated: Euler-Heisenberg, Born-Infeld and the Modified Maxwell ED. Throughout the paper, we shall justify why we follow the unusual path of connecting, in a single Lagrangian density, three pieces of physics beyond the Standard Model, namely, non-linearity, axions and LSV. We anticipate that we shall not be claiming that the simultaneous introduction of these three topics beyond the Standard Model will bring new insights or clues for the efforts to detect axions or to constrain parameters associate to both non-linear ED and LSV physics . Our true goal is to actually inspect and describe how axionic, non-linear and LSV effects interfere with one another whenever physical entities like refraction indices and birefringence are computed in presence of an external constant and homogeneous magnetic background.Comment: 27 pages, no figure

The axion-photon mixing in non-linear electrodynamic scenarios

In this contribution, we re-assess some aspects of axionic electrodynamics by coupling non-linear electromagnetic effects to axion physics. We present a number of motivations to justify the coupling of the axion to the photon in terms of a general non-linear extension of the electromagnetic sector. Our emphasis in the paper relies on the investigation of the constitutive permittivity and permeability tensors, for which the axion contributes by introducing dependence on the frequency and wave vector of the propagating radiation. Also, we point out how the axion mass and the axion-photon-photon coupling constant contribute to a dispersive behavior of the electromagnetic waves, in contrast to what happens in the case of non-linear extensions, when effective refractive indices appear which depend only on the direction of the propagation with respect to the external fields. The axion changes this picture by yielding refractive indices with dependence on the wavelength. We apply our results to the special case of the Born-Infeld Electrodynamics and we show that it becomes birefringent whenever the axion is coupled. The paper is supplemented by an Appendix, where we approach the recent discussion on the controversy in defining the Poynting vector of axionic electrodynamics. We present our path to tackle the question and give the expressions we work out for both the Poynting vector and the momentum density transported by the waves.Comment: 30 pages, no figure

Cintilografia de perfusão miocárdica utilizando apenas estresse é seguro em pacientes de baixa probabilidade pré-teste de doença arterial coronária e reduz exposição à radiação

Introdução: Cintilografia de Perfusão Miocárdica (CPM) confere prognósticas e diretrizes atuais que recomendam realização do exame sob o protocolo padrão de repouso/estresse (R/E). Objetivo: Avaliar o prognóstico da CPM utilizando o protocolo de apenas estresse em população de baixo risco. Métodos: O estudo prospectivo incluiu 46 pacientes consecutivos após CPM. Aqueles que preencheram os seguintes critérios na admissão realizaram a fase de estresse inicialmente: 1. Baixa probabilidade pré-teste (<50%) de Doença Arterial Coronária (DAC) significativa baseada nos critérios de Diamond e Forrester; 2. Capazes de realizar estresse em esteira ergométrica; 3. Não terem diagnóstico prévio de DAC; 4. Terem o eletrocardiograma (ECG) de repouso interpretável. A indicação da CPM foi teste ergométrico prévio anormal por alterações de ST em 63% e angina atípica em 22%. A probabilidade média pré-teste de DAC foi de 11,3% (4% - 46%). A média das idades foi de 40 anos (30 - 49), 60% era do sexo feminino. Os incluídos foram submetidos à fase de estresse, sob o protocolo de Bruce; a frequência cardíaca (FC) média alcançada foi 92,9% da FC máxima prevista para a idade. Todos os envolvidos alcançaram carga de trabalho ≥ 6 METS (média 9,4 MET). Se a imagem de estresse fosse normal de forma inequívoca era finalizada o exame. Qualquer suspeita de artefatos e/ou presença de defeitos perfusionais no estresse, os participantes realizavam o repouso e eram excluídos do estudo. Resultados: O ECG de estresse revelou alterações do seguimento ST em 30% dos participantes, com padrão ascendente em 35%, horizontal em 7% e descendente em 57%. Nenhum deles referiu angina na fase de estresse. A duração média do exame foi de 115 min (protocolo padrão R/E 240 min). A dose do radio fármaco (Tc99m-MIBI) injetada foi significantemente menor do que a prevista para o protocolo padrão (9,2 mCi, vs 33,9 mCi – p<0,00001) com redução a exposição à radiação de 77% (2,5 mSv vs 11,4mSv). O seguimento foi obtido em todos os participantes com uma média de 19,9 meses (variando de 6 a 34). Nenhum evento mórbido (óbito, infarto do miocárdio fatal ou não fatal) ou revascularização do miocárdio ocorreu durante o período de seguimento. Conclusão: A CPM normal utilizando o protocolo de estresse em indivíduos de baixa probabilidade pré-teste de DAC, confere bom prognóstico, não tendo ocorrido eventos fatais e/ou revascularização em um seguimento de 19,9 meses, com importante redução a exposição à radiação e com protocolo de realização mais curto

Valorization of chestnut shells for hydrogen production by Clostridium butyricum fermentation

Chestnut shell s (CS) is an agronomic waste generated from the peeling process of the chestnut fruit. It is well-known that the extract of CS contains high amounts of tannins, which are polyphenolic antioxidants1, but this agronomic residue also contains about 36% sugars in form of polysaccharides, and no utilization of chestnut shells as potential source of fermentable sugars has been considered so far. As consequence, this waste represents an interesting exploitable source for monosaccharides production, and in this study we evaluated the potential of biohydrogen production from CS hydrolyzate

a case study from Portugal

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Esterase production by Aureobasidium pullulans URM 7059 in stirred tank and airlift bioreactors using residual biodiesel glycerol as substrate

Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.bej.2021.107954.Aureobasidium pullulans URM 7059 produced esterase using residual glycerol from biodiesel as the sole carbon source. The culture medium containing residual glycerol (0.1% v/v), (NH4)2SO4 (4g/L), and yeast extract (8g/L) resulted in the highest esterase production using shake-flasks. The enzyme exhibited a molar mass of 50kDa and was stable at neutral pH and temperatures below 30°C. The cations Cu2+ and Al3+ did not affect the esterase activity, while Ca2+ promoted the highest activity loss. The enzyme kinetic parameters were determined using different substrates (p-nitrophenylcaprylate and p-nitrophenylbutyrate). Km and Vmax were 1.4mM and 218µmolmin-1 for p-NPC, and 1.55mM and 76.7µmolmin-1 for p-NPB. The esterase production was further evaluated using stirred tank and 2-L airlift bioreactors. The airlift reactor operating at the highest air flow rate (8L/min) increased the enzyme productivity 3-fold compared to the shake-flasks experiments. However, the crude enzymatic extract showed 3 active protein bands by zymography with molecular masses of 172kDa, 66kDa, and 40kDa approximately, suggesting that the pattern of enzyme production changed due to aeration. The crude enzyme degraded the MACO-Sty biopolymer in 14 days, being stable in a wide range of pH (7.0 9.0) and temperatures (40°C 80°C). The results suggest that this enzyme is a promising catalyst in remediation processes.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004), projects MultiBiorefinery (POCI-01-0145-FEDER016403) and Lignozymes (POCI-01-0145-FEDER-029773), all funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. In Brazil, this study was financed in part by the Coordenaçao ˜ de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. The authors also thank the CNPq and FUNCAP for financial support.info:eu-repo/semantics/publishedVersio

Sugarcane bagasse delignification with potassium hydroxide for enhanced enzymatic hydrolysis

The optimization of an alkaline pretreatment process for the delignification of sugarcane bagasse (SCB) to enhance the subsequent enzymatic hydrolysis was performed according to the Doehlert uniform shell design. In this experimental design, the effect of two factors—potassium hydroxide (KOH) concentration and autoclaving time at 121 C (1 atm)—on cellulose, hemicellulose, or the total polysaccharide and lignin content in SCB was evaluated. This response surface methodology revealed that KOH concentration is the factor that most influences the chemical characteristics of treated SCB (SCBt), with optimal conditions for the highest delignification being KOH in the range 5–10% (w/v) and an autoclaving time of 35 min, which provides an average of 97% total polysaccharides without inhibitor accumulation (furfural, 5-hydroxymethyl furfural) and #5% lignin. SCBt samples from two pretreatment conditions (KOH 3.25% – 13 min; KOH 10% – 35 min) were selected, based on the greatest delignification (70–74%) and polysaccharide availability (95–97%) after pretreatment, and further hydrolysed for fermentable sugar production. High sugar yields were obtained from both the pretreated samples (866 to 880 mg sugar per g biomass, respectively) in contrast with the 129 mg sugar per g raw biomass obtained from untreated SCB. These results demonstrate the effectiveness of KOH alkali pretreatments, which improves the overall digestibility of raw SCB polysaccharides from about 18% up to 91%. However, harsh alkali treatment (KOH 10%) is the most effective if the highest glucose/xylose ratio in the final sugar-rich hydrolysate is the aim. Hence, the use of sugar-rich hydrolysates obtained from SCBt as the carbon source for industrial purposes may provide a sustainable and economic solution for the production of bio-based added-value products, such as second generation (2G) bioethanol