Physical and Morphological Structure of Chicken Feathers (Keratin Biofiber) in Natural, Chemically and Thermally Modified Forms

Because of the constant challenge to preserve the environment and the search for new materials, a comparative study was carried out using keratin fiber, a fibrous protein, found in the chicken feathers. Five different samples of the feather were analyzed by Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). First in their natural form Keratin Fiber (KF);the second treated with sodium hydroxide (KFNaOH);the third and fourth samples were semi carbonized at 220℃ in an oven without atmospheric control for 24 hours (samples obtained: Clear brown (SCFC) and Dark brown (SCFD));and the fifth sample was carbonized by pyrolysis Carbonized Feathers (CF). The SEM result shows that the KF has a hollow structure, with knots and hooks. The KFNaOH structure presented rougher than that of the KF, but lost their hooks. The SCFC and SCFD presented brittle structures, but preserved the hollow structure of KF;however, it was only noticeable to a magnification of 3000 times. On the other hand, the CF, was shiny, black, and showed a higher amount of porosity with open micro-pores and micro-tubes, preserved the hollow structure of KF than any other samples studied, and also presented well-defined closed micro-tubes. From the XRD analysis of the KF, CF, KFNaOH, SCFC and SCFD, presented semi-crystalline structures, with the following indices of crystallinity, 20.09%, 18.93%, 17.97%, 15.02% and 14.31%, respectively. The CF presented smaller size crystallites, in between the micro- particulates, around 27 nm and the KFNaOH with larger size around 74 nm. From this study it was concluded that micro-porous carbon material from chicken feathers (KF) could be efficiently obtained through pyrolysis.

Energy stored in nanoscale water capillary bridges formed between chemically heterogeneous surfaces with circular patches

The formation of nanoscale water capillary bridges(WCBs) between chemically heterogeneous(patchy) surfaces plays an important role in different scientific and engineering applications, including nanolithography, colloidal aggregation, and bioinspired adhesion. However, the properties of WCB of nanoscale dimensions remain unclear. Using molecular dynamics simulations, we investigate the geometrical and thermodynamic properties of WCB confined between chemically heterogeneous surfaces composed of circular hydrophilic patches on a hydrophobic background. We find that macroscopic capillary theory provides a good description of the WCB geometry and forces induced by the WCB on the confining surfaces even in the case of surface patches with diameters of only 4 nm. Upon stretching, the WCB contact angle changes from hydrophobic-like values(θ > 90°) to hydrophilic-like values(θ < 90°) until it finally breaks down into two droplets at wall separations of ~9–10 nm. We also show that the studied nanoscale WCB can be used to store relevant amounts of energy EPand explore how the walls patch geometry can be improved in order to maximize EP. Our findings show that nanoscale WCB can, in principle, be exploited for the design of clean energy storage devices as well as actuators that respond to changes in relative humidity. The present results can also be of crucial importance for the understanding of water transport in nanoporous media and nanoscale engineering systems.

Effect of Addition of Sodium Citrate in Plasma Extraction for Venous Blood Glucose Determination

Background: Diabetes Mellitus (DM) is one of the major health problems and morbidity causes in contemporary society worldwide. Recently, it has been suggested that the addition of citrate in plasma extraction decreases glucose degradation by endogenous enzymes, which could contribute in an important manner to the diagnosis of DM. However, this strategy has not been sufficiently evaluated. The present study aimed to evaluate glucose determination in serum and in plasma obtained with different anticoagulants. Methods: We obtained 20 venous blood paired samples on consecutive days from the same individual, collected in dry tubes with separator gel and in glass tubes with sodium fluoride and EDTA-K2, either in the presence or absence of sodium citrate. Glucose was determined by an oxidase/peroxidase method using the same system by a unique analyst. Results: Serum determinations were constantly higher than in plasma

De Novo Design of a Highly Stable Ovoid TIM Barrel:Unlocking Pocket Shape towards Functional Design

The ability to finely control the structure of protein folds is an important prerequisite to functional protein design. The TIM barrelfold is an important target for these efforts as it is highly enriched for diverse functions in nature. Although a TIM barrel proteinhas been designed de novo, the ability to finely alter the curvature of the central beta barrel and the overall architecture of the foldremains elusive, limiting its utility for functional design. Here, we report the de novo design of a TIM barrel with ovoid (twofold)symmetry, drawing inspiration from natural beta and TIM barrels with ovoid curvature. We use an autoregressive backbonesampling strategy to implement our hypothesis for elongated barrel curvature, followed by an iterative enrichment sequencedesign protocol to obtain sequences which yield a high proportion of successfully folding designs. Designed sequences arehighly stable and fold to the designed barrel curvature as determined by a 2.1Å resolution crystal structure. The designs showrobustness to drastic mutations, retaining high melting temperatures even when multiple charged residues are buried in thehydrophobic core or when the hydrophobic core is ablated to alanine. As a scaffold with a greater capacity for hosting diversehydrogen bonding networks and installation of binding pockets or active sites, the ovoid TIM barrel represents a major steptowards the de novo design of functional TIM barrels.

Antinociceptive and anti-inflammatory activities of leaf extracts from Annona tomentosa R.E.Fr

OBJECTIVE：Annona tomentosa R.E.Fr is a species not endemic to Brazil that belongs to the phytogeographic areas of the Amazon,Cerrado and Pantanal.Popularly known as“araticum rasteiro”or“araticum de moita”,A.tomentosa is edible and tea made from the leaves has been used as an antiinflammatory by native communities.There is no scientific evidence for these uses of A.tomentosa,especially those related to the control of pain and inflammation.For this reason,in the present study we evaluated the antinociceptive and anti-inflammatory activities of partitions from the methanolic extract of A.tomentosa leaves（A.tomentosa leaf methanolic extract（ATFM）in hexane partition：ATFM-H;ATFM in dichloromethane partition：ATFM-D;ATFM in ethyl acetate partition：ATFM-Ac;ATFM in butanol partition：ATFM-B）in mice.METHODS：The antinociceptive effects of leaf extracts from A.tomentosa were evaluated by abdominal writhing and tail-flick tests,while the anti-inflammatory effects were evaluated by paw oedema and air-pouch tests.The locomotor activity was evaluated with the open-field test.Furthermore,we evaluated the possible action mechanism of A.tomentosa,using naloxone,nitro-L-arginine methyl ester,glibenclamide,atropine,naltrindole and norbinaltorphimine in tail-flick tests.The productions of tumor necrosis factorα（TNF-α）and interleukin（IL）-1βwere also evaluated.RESULTS：The chromatographic fractionation of the partitions of the methanolic extract from the leaves of A.tomentosa revealed the presence of diterpenes,flavonoids,and steroids compounds.From the analysis of the hexane partition kaurenoic acid was identified as the major component.ATFM-H and ATFM-D had a significant antinociceptive effect in acute pain models in mice.The ATFM-H showed central antinociceptive effect from the involvement of theδopioid receptors,without causing alterations in the locomotor activity of the mice,while ATFM-D was effective in decreasing paw oedema and TNF-α and IL-1β production.CONCLUSION：These results demonstrate that leaf extracts from A.tomentosa present antinociceptive and anti-inflammatory effects that can to be used in relieving algesic and inflammatory conditions.

Effects of sulforaphane on brain mitochondria: mechanistic view and future directions

The organosulfur compound sulforaphane(SFN;C6H11NOS2) is a potent cytoprotective agent promoting antioxidant, anti-inflammatory, antiglycative, and antimicrobial effects in in vitro and in vivo experimental models. Mitochondria are the major site of adenosine triphosphate(ATP) production due to the work of the oxidative phosphorylation(OXPHOS) system. They are also the main site of reactive oxygen species(ROS) production in nucleated human cells. Mitochondrial impairment is central in several human diseases, including neurodegeneration and metabolic disorders. In this paper, we describe and discuss the effects and mechanisms of action by which SFN modulates mitochondrial function and dynamics in mammalian cells. Mitochondria-related pro-apoptotic effects promoted by SFN in tumor cells are also discussed. SFN may be considered a cytoprotective agent, at least in part, because of the effects this organosulfur agent induces in mitochondria. Nonetheless, there are certain points that should be addressed in further experiments, indicated here as future directions, which may help researchers in this field of research.