We explore ultrafast charge transfer (CT) resonantly induced by hard X-ray radiation in organic thiophene-based polymers at the sulfur K-edge. A combination of core-hole clock spectroscopy with ...real-time propagation time-dependent density functional theory simulations gives an insight into the electron dynamics underlying the CT process. Our method provides control over CT by a selective excitation of a specific resonance in the sulfur atom with monochromatic X-ray radiation. Our combined experimental and theoretical investigation establishes that the dominant mechanism of CT in polymer powders and films consists of electron delocalisation along the polymer chain occurring on the low-femtosecond time scale.
Ultrafast charge transfer along the polymer chains is triggered by a selective resonant core-excitation of the sulfur atom in P3HT films and powders. Our approach opens perspectives for studies on intra-molecular conductivity in organic molecules.
Anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. Molecular catalysts, however, are ...far less stable than traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here we applied a non-covalent 'click' chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces through host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and enables the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and the readsorption of fresh guest.
Ionization Energy of Liquid Water Revisited Perry, Conaill F; Zhang, Pengju; Nunes, Fernanda B ...
The journal of physical chemistry letters,
03/2020, Letnik:
11, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The ionization energy of liquid water is one of its most fundamental properties, an important benchmark for first-principles electronic-structure calculations and a crucial reference in the growing ...field of liquid-phase photoelectron spectroscopy. Despite this significance, a consensus on its value appears to be missing in the literature. Therefore, we use a monochromatized high-harmonic light source to perform detailed measurements of the ionization energy of liquid water in the presence of a tunable bias voltage applied to the liquid jet. Our results suggest that this simple method is sufficient to simultaneously compensate the effects of the streaming potential and that of the vacuum-level offset between the liquid and the photoelectron spectrometer. Our measurements yield corrected values of the vertical and adiabatic ionization energies of the 1b1 band of bulk liquid water of 11.67(15) and 10.12(15) eV, respectively. Our method is broadly applicable and is likely to result in corrections to the measured ionization energies of solvated species as well.
Glycoside hydrolase family 5 (GH5) harbors diverse substrate specificities and modes of action, exhibiting notable molecular adaptations to cope with the stereochemical complexity imposed by ...glycosides and carbohydrates such as cellulose, xyloglucan, mixed‐linkage β‐glucan, laminarin, (hetero)xylan, (hetero)mannan, galactan, chitosan, N‐glycan, rutin and hesperidin. GH5 has been divided into subfamilies, many with higher functional specificity, several of which have not been characterized to date and some that have yet to be discovered with the exploration of sequence/taxonomic diversity. In this work, the current GH5 subfamily inventory is expanded with the discovery of the GH5_57 subfamily by describing an endo‐β‐mannanase (CapGH5_57) from an uncultured Bacteroidales bacterium recovered from the capybara gut microbiota. Biochemical characterization showed that CapGH5_57 is active on glucomannan, releasing oligosaccharides with a degree of polymerization from 2 to 6, indicating it to be an endo‐β‐mannanase. The crystal structure, which was solved using single‐wavelength anomalous diffraction, revealed a massively redesigned catalytic interface compared with GH5 mannanases. The typical aromatic platforms and the characteristic α‐helix‐containing β6–α6 loop in the positive‐subsite region of GH5_7 mannanases are absent in CapGH5_57, generating a large and open catalytic interface that might favor the binding of branched substrates. Supporting this, CapGH5_57 contains a tryptophan residue adjacent and perpendicular to the cleavage site, indicative of an anchoring site for a substrate with a substitution at the −1 glycosyl moiety. Taken together, these results suggest that despite presenting endo activity on glucomannan, CapGH5_57 may have a new type of substituted heteromannan as its natural substrate. This work demonstrates the still great potential for discoveries regarding the mechanistic and functional diversity of this large and polyspecific GH family by unveiling a novel catalytic interface sculpted to recognize complex heteromannans, which led to the establishment of the GH5_57 subfamily.
A phylogenetically distant glycoside hydrolase family 5 member retrieved from the capybara gut microbiome displays a large and open catalytic interface that is adapted to recognize complex heteromannans, establishing the novel GH5_57 subfamily. This study expands the current mechanistic and functional understanding of one of the largest GH families.
Reports have shown that the onset of diabetes mellitus (DM) in patients previously diagnosed with asthma decreases asthmatic symptoms, whereas insulin aggravates asthma. The present study evaluated ...the modulatory effect of insulin on the development of allergic airway inflammation in diabetic mice.
To evaluate the effects of relative insulin deficiency, an experimental model of diabetes was induced by a single dose of alloxan (50 mg/kg, i.v.). After 10 days, the mice were sensitized with ovalbumin OVA, 20 μg and 2 mg of Al(OH)
, i.p.. A booster immunization was performed 6 days after the first sensitization 20 μg of OVA and 2 mg of Al(OH)
, i.p.. The OVA challenge (1 mg/mL) was performed by daily nebulization for 7 days. Diabetic animals were treated with multiple doses of neutral protamine Hagedorn (NPH) before each challenge with OVA. The following parameters were measured 24 h after the last challenge: (a) the levels of p38 MAP kinase, ERK 1/2 MAP kinases, JNK, STAT 3, and STAT 6 in lung homogenates; (b) the serum profiles of immunoglobulins IgE and IgG1; (c) the concentrations of cytokines (IL-4, IL-5, IL-10, IL-13, TNF-α, VEGF, TGF-β, and IFN-γ) in lung homogenates; (d) cells recovered from the bronchoalveolar lavage fluid (BALF); (e) the profiles of immune cells in the bone marrow, lung, thymus, and spleen; and (f) pulmonary mechanics using invasive (FlexiVent) and non-invasive (BUXCO) methods.
Compared to non-diabetic OVA-challenged mice, OVA-challenged diabetic animals showed decreases in ERK 1 (2-fold), ERK 2 (7-fold), JNK (phosphor-54) (3-fold), JNK/SAPK (9-fold), STAT3 (4-fold), the levels of immunoglobulins, including IgE (1-fold) and IgG1 (3-fold), cytokines, including Th2 profile cytokines such as IL-4 (2-fold), IL-5 (2-fold), IL-13 (4-fold), TNF-α (2-fold), VEGF (2-fold), and TGF-β (2-fold), inflammatory infiltrates (14-fold), T cells, NK cells, B cells and eosinophils in the bone marrow, lung, thymus and spleen, and airway hyperreactivity. STAT6 was absent, and no eosinophilia was observed in BALF. Insulin treatment restored all parameters.
The data suggested that insulin modulates immune cell phenotypes and bronchial hyperresponsiveness in the development of allergic airway inflammation in diabetic mice.
BACKGROUND: Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest spotted fever of the world. In most of the BSF-endemic areas, capybaras (Hydrochoerus ...hydrochaeris) are the principal host for the tick Amblyomma cajennense, which is the main vector of BSF. METHODS: In 2012, a BSF case was confirmed in a child that was bitten by ticks in a residential park area inhabited by A. cajennense-infested capybaras in Itú municipality, southeastern Brazil. Host questing A. cajennense adult ticks were collected in the residential park and brought alive to the laboratory, where they were macerated and intraperitoneally inoculated into guinea pigs. A tick-inoculated guinea pig that presented high fever was euthanized and its internal organs were macerated and inoculated into additional guinea pigs (guinea pig passage). Tissue samples from guinea pig passages were also used to inoculate Vero cells through the shell vial technique. Infected cells were used for molecular characterization of the rickettsial isolate through PCR and DNA sequencing of fragments of three rickettsial genes (gltA, ompA, and ompB). Blood serum samples were collected from 172 capybaras that inhabited the residential park. Sera were tested through the immunofluorescence assay using R. rickettsii antigen. RESULTS: A tick-inoculated guinea pig presented high fever accompanied by scrotal reactions (edema and marked redness). These signs were reproduced by consecutive guinea pig passages. Rickettsia was successfully isolated in Vero cells that were inoculated with brain homogenate derived from a 3ʳᵈpassage-febrile guinea pig. Molecular characterization of this rickettsial isolate (designated as strain ITU) yielded DNA sequences that were all 100% identical to corresponding sequences of R. rickettsii in Genbank. A total of 83 (48.3%) out of 172 capybaras were seroreactive to R. rickettsii, with endpoint titers ranging from 64 to 8192. CONCLUSIONS: A viable isolate of R. rickettsii was obtained from the tick A. cajennense, comprising the first viable R. rickettsi isolate from this tick species during the last 60 years. Nearly half of the capybara population of the residential park was seroreactive to R. rickettsii, corroborating the findings that the local A. cajennense population was infected by R. rickettsii.
Esse artigo aborda o jornalismo independente feminista e as mídias independentes brasileiras identificadas com o feminismo e as questões de gênero. Realizamos um comparativo entre as sete mídias ...independentes feministas brasileiras (AzMina, Catarinas, Cientista Que Virou Mãe, Gênero e Número, Lado M, Nós, Mulheres da Periferia e Think Olga), apresentando suas características editoriais e aspectos que orientam a sua prática jornalística. Essas mídias evidenciam temas da agenda feminista para a esfera pública, mostrando outros sentidos através de seus discursos e problematizando as estruturas que geram desigualdades e violências.
Blomia tropicalis mite is highly prevalent in tropical and subtropical regions and it is associated with allergic diseases such as rhinitis and asthma. By using an OVA‐model of allergic lung disease, ...we have previously shown that sensitization in the presence of toll like receptors (TLRs) agonists attenuates subsequent OVA‐induced allergic responses. Here, we evaluated the effect of CpG‐ODN, a specific synthetic TLR‐9 agonist, on the development of experimental asthma induced by Blomia tropicalis extract, a relevant source of aeroallergens. Among different protocols of Blomia tropicalis extract sensitization, the subcutaneous sensitization in the presence of alum adjuvant induced the highest Th2 responses, including high IgE levels. Adsorption of CpG to Blomia tropicalis extract/Alum attenuated the airway hyperreactivity, the infiltration of inflammatory cells including eosinophils, and the IL‐5 content in BAL. In addition, lung peribronchial inflammatory infiltrate, mucus production and IL‐5‐producing CD3+CD4+ T cells were significantly reduced in the Blomia tropicalis extract/Alum+CpG group. Importantly, CpG inhibited total IgE production as well as active systemic or cutaneous anaphylaxis reactions. Inhibition of pulmonary Th2 responses was associated with increased IL‐10 production but not with IFN‐γ production. Notably, in IL‐10‐deficient mice, sensitization with OVA/Alum+CpG resulted in intense lung neutrophilia and IFN‐γ production, indicating that IL‐10 is necessary to inhibit subsequent Th1 immunity. Our work highlights the mechanisms of allergy attenuation by CpG and it indicates the potential use of Alum‐based formulation with CpG to treat allergic processes.
CpG dampens allergic responses induced by Blomia tropicalis HDM extract. Sensitization to Blomia tropicalis house dust mite (HDM) with CpG adsorbed to alum adjuvant prevents the development of HDM‐Blomia tropicalis‐induced allergic lung inflammation and anaphylactic Ab production.
Emerging literature demonstrates that eating time and frequency are associated with quality and quantity of food consumption and anthropometric measurements. Considering that unhealthy dietary ...choices and obesity are important modifiable risk factors for breast cancer incidence and recurrence, this subject is relevant and has not been studied sufficiently in breast cancer survivors.
This study’s aim was to examine the association of eating time and frequency with diet quality, quantity of food consumption, anthropometric measurements, and body composition parameters in female breast cancer survivors using tamoxifen.
This was a cross-sectional study.
This study was conducted from March 2015 to March 2016 at a Brazilian university hospital (Clinic’s Hospital, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil) and included an assessment of 84 female breast cancer survivors using tamoxifen (mean SD age was 53.1 8.7 years).
Quantitative dietary assessment consisted of three 24-hour dietary recalls. The Brazilian Healthy Eating Index Revised was used for the qualitative diet analysis. Participants were classified by median eating time (early or late eaters of breakfast, lunch, and dinner), as well as by considering the middle time point between the first and last meal of the day (early or late midpoint eaters). Participants were also classified by median eating frequency (<5 or ≥5 eating episodes per day). Anthropometric measurements and body fat percentage by bioelectrical impedance were obtained.
Generalized linear models and generalized mixed models were used to assess the associations between variables.
Early breakfast and dinner eating and early midpoint eating were associated with better scores for specific Brazilian Healthy Eating Index Revised components (P < .05). Early breakfast and dinner eating were also associated with better scores for the total index (P = .035 and P = .017, respectively). Early dinner eaters and early midpoint eaters had significantly lower daily energy consumption (P = .007 and P = .002, respectively). Eating ≥5 episodes per day was also associated with better scores of specific Brazilian Healthy Eating Index Revised components and the total index (P < .05). No significant associations between eating time and frequency with anthropometric measurements and body composition parameters were found (P > .05). However, women in the healthy body mass index category vs women in the overweight/obesity category had higher energy consumption at breakfast (P = .046).
Earlier food intake time was associated with better diet quality and lower daily energy consumption. Higher frequency of eating was also associated with better diet quality. Future studies, such as randomized controlled trials, are needed to evaluate interventions addressing the timing and frequency of meals and their effect on diet quality and quantity in breast cancer survivors.
Polycystic Ovary Syndrome (PCOS) is characterized by hyperandrogenism, amenorrhea, and polycystic ovaries. This endocrinopathy is associated with many metabolic disorders such as dyslipidemia and ...insulin resistance, with increased risk of type 2 diabetes mellitus, metabolic syndrome, and cardiovascular complications. Inflammation is likely to play an important role in the promoting these metabolic imbalances, while prothrombotic and pro-oxidative mechanisms further contribute to the cardiovascular risk of these patients. The etiology of PCOS is still not fully understood, but there is evidence of genetic and environmental components. This review aims to discuss some molecular pathways associated with PCOS that could contribute to the better understanding about this syndrome. Recent evidence suggests that intrauterine exposure of female mice to an excess of anti-Müllerian hormone may induce PCOS features in their post-natal life. High cytokine levels and cytokine gene polymorphisms also appear to be associated with the pathophysiology of PCOS. Furthermore, high levels of microparticles may contribute to the altered hemostasis and enhanced inflammation in PCOS. All these mechanisms may be relevant to clarify some aspects of PCOS pathogenesis and inspire new strategies to prevent the syndrome as well as treat its symptoms and mitigate the risk of long-term complications.
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