Multiscale Brazil nut effects in bioturbated sediment.
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ABSTRACT:
SUBMITTER: Savranskaia T
PROVIDER: S-EPMC9259689 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Sedimentation is a ubiquitous phenomenon across many fields of science, such as geology, astrophysics, and soft matter. Sometimes, sedimentation leads to unusual phenomena, such as the Brazil-nut effect, where heavier (granular) particles reside on top of lighter particles after shaking. We show experimentally that a Brazil-nut effect can be realized in a binary colloidal system of long-range repulsive charged particles driven purely by Brownian motion and electrostatics without the need for activity. Using theory, we argue that not only the mass-per-charge for the heavier particles needs to be smaller than the mass-per-charge for the lighter particles but also that at high overall density, the system can be trapped in a long-lived metastable state, which prevents the occurrence of the equilibrium Brazil-nut effect. Therefore, we envision that our work provides valuable insights into the physics of strongly interacting systems, such as partially glassy and crystalline structures. Finally, our theory, which quantitatively agrees with the experimental data, predicts that the shapes of sedimentation density profiles of multicomponent charged colloids are greatly altered when the particles are charge-regulating with more than one ion species involved. Hence, we hypothesize that sedimentation experiments can aid in revealing the type of ion adsorption processes that determine the particle charge and possibly the value of the corresponding equilibrium constants.
| S-EPMC9992820 | biostudies-literature
Project description:Peanut and tree-nut allergies have attracted considerable attention because of their frequency and their lifelong persistence. Brazil-nut (Bertholletia excelsa) allergies have been well documented and the 11S legumin-like seed storage protein Ber e 2 (excelsin) is one of the two known brazil-nut allergens. In this study, Ber e 2 was extracted from brazil-nut kernels and purified to high purity by crystalline precipitation and gel-filtration chromatography. Well diffracting single crystals were obtained using the hanging-drop vapour-diffusion method. A molecular-replacement structural solution has been obtained. Refinement of the structure is currently under way.
| S-EPMC2339761 | biostudies-literature
Project description:ObjectivesTo investigate the effect of partially defatted Granulated Brazil nut (GBN) on biomarkers of oxidative stress and antioxidant status of hypertensive and dyslipidemic patients on nutrition and drug approaches.MethodsNinety one hypertensive and dyslipidemic subjects of both genders (51.6 % men), mean age 62.1 ± 9.3 years, performed a randomized crossover trial, double-blind, placebo controlled. Subjects received a diet and partially defatted GBN 13 g per day (≈227.5 μg/day of selenium) or placebo for twelve weeks with four-week washout interval. Anthropometric, laboratory and clinic characteristics were investigated at baseline. Plasma selenium (Se), plasma glutathione peroxidase (GPx3) activity, total antioxidant capacity (TAC), 8-epi PGF2α and oxidized LDL were evaluated at the beginning and in the end of each intervention.ResultsGBN intake significantly increased plasma Se from 87.0 ± 16.8 to 180.6 ± 67.1 μg/L, increased GPx3 activity in 24,8% (from 112.66 ± 40.09 to 128.32 ± 38.31 nmol/min/mL, p < 0,05), and reduced 3.25% of oxidized-LDL levels (from 66.31 ± 23.59 to 60.68 ± 20.88 U/L, p < 0.05). An inverse association between GPx3 and oxidized LDL levels was observed after supplementation with GBN by simple model (β -0.232, p = 0.032) and after adjustment for gender, age, diabetes and BMI (β -0.298, p = 0.008). There wasn't association between GPx3 and 8-epi PGF2α (β -0.209, p = 0.052) by simple model.ConclusionThe partially defatted GBN intake has a potential benefit to increase plasma selenium, increase enzymatic antioxidant activity of GPx3 and to reduction oxidation in LDL in hypertensive and dyslipidemic patients.Trial registrationClinicalTrials.gov Identifier NCT01990391; November 20, 2013.
| S-EPMC4477321 | biostudies-literature
Project description:A new Penicillium species, P. excelsum, is described here using morphological characters, extrolite and partial sequence data from the ITS, β-tubulin and calmodulin genes. It was isolated repeatedly using samples of nut shells and flowers from the brazil nut tree, Bertolletia excelsa, as well as bees and ants from the tree ecosystem in the Amazon rainforest. The species produces andrastin A, curvulic acid, penicillic acid and xanthoepocin, and has unique partial β-tubulin and calmodulin gene sequences. The holotype of P. excelsum is CCT 7772, while ITAL 7572 and IBT 31516 are cultures derived from the holotype.
| S-EPMC4696661 | biostudies-literature
Project description:BackgroundNUT midline carcinoma is a rare and aggressive subset of squamous cell carcinoma, which is characterized by the translocation of nuclear protein in testis gene that is mostly fused with bromodomain and extraterminal family proteins. We describe here the first Brazilian case of NUT midline carcinoma with BRD4-NUT fusion detected in a next-generation sequencing panel and we present the clinical evolution of this patient.Case presentationA 42-year-old Caucasian man was diagnosed with poorly differentiated squamous cell carcinoma of the left maxillary sinus, with negative in situ hybridization for Epstein-Barr encoding region and human papillomavirus genotyping. He received induction therapy, chemoradiotherapy with weekly systemic chemotherapy, and, concurrently, weekly intra-arterial chemotherapy. New imaging evaluation, 1 month after the end of the last treatment, revealed a good partial response in the primary lesion. However, positron emission tomography-computed tomography showed multiple suspicious lesions in his bones and lungs, which were histologically confirmed. He died exactly 2 months after metastatic disease was diagnosed.ConclusionsNUT midline carcinoma is usually very aggressive. Currently, there is no standard of care for treatment of NUT midline carcinoma. The definitive diagnosis must be by demonstration of NUTM1 rearrangement. Immunohistochemical staining of greater than 50% of tumor nuclei on formalin-fixed paraffin-embedded tissue using the monoclonal rabbit antibody to NUT (clone C52B1), has a specificity of 100%, and sensitivity of 87% for the diagnosis of NUT midline carcinoma. Our case is the first Brazilian case of NUT midline carcinoma with BRD4-NUT fusion.
| S-EPMC6731562 | biostudies-literature
Project description:Recent evidence suggests that replacing saturated fat with unsaturated fat is beneficial for cardiovascular health. This study compared the effects of Brazil nut oil (BNO) and soybean oil (SO) supplementation for 30 days on anthropometric, blood pressure, biochemical, and oxidative parameters in patients with metabolic syndrome (MS). Thirty-one patients with MS were randomly allocated to receive 30 sachets with 10 mL each of either BNO (n = 15) or SO (n = 16) for daily supplementation. Variables were measured at the beginning of the study and after 30 days of intervention. No change in anthropometric and blood pressure variables were observed (p > 0.05). Total (p = 0.0253) and low-density lipoprotein (p = 0.0437) cholesterol increased in the SO group. High-density lipoprotein cholesterol decreased (p = 0.0087) and triglycerides increased (p = 0.0045) in the BNO group. Malondialdehyde levels decreased in the BNO group (p = 0.0296) and total antioxidant capacity improved in the SO group (p = 0.0110). Although the addition of oils without lifestyle interventions did not affect anthropometric findings or blood pressure and promoted undesirable results in the lipid profile in both groups, daily supplementation of BNO for 30 days decreased lipid peroxidation, contributing to oxidative stress reduction.
| S-EPMC7019763 | biostudies-literature
Project description:We sought to examine the effects of daily consumption of macadamia nuts on body weight and composition, plasma lipids and glycaemic parameters in a free-living environment in overweight and obese adults at elevated cardiometabolic risk. Utilising a randomised cross-over design, thirty-five adults with abdominal obesity consumed their usual diet plus macadamia nuts (~15 % of daily calories) for 8 weeks (intervention) and their usual diet without nuts for 8 weeks (control), with a 2-week washout. Body composition was determined by bioelectrical impedance; dietary intake was assessed with 24-h dietary recalls. Consumption of macadamia nuts led to increased total fat and MUFA intake while SFA intake was unaltered. With mixed model regression analysis, no significant changes in mean weight, BMI, waist circumference, percent body fat or glycaemic parameters, and non-significant reductions in plasma total cholesterol of 2⋅1 % (-4⋅3 mg/dl; 95 % CI -14⋅8, 6⋅1) and low-density lipoprotein (LDL-C) of 4 % (-4⋅7 mg/dl; 95 % CI -14⋅3, 4⋅8) were observed. Cholesterol-lowering effects were modified by adiposity: greater lipid lowering occurred in those with overweight v. obesity, and in those with less than the median percent body fat. Daily consumption of macadamia nuts does not lead to gains in weight or body fat under free-living conditions in overweight or obese adults; non-significant cholesterol lowering occurred without altering saturated fat intake of similar magnitude to cholesterol lowering seen with other nuts. Clinical Trial Registry Number and Website: NCT03801837 https://clinicaltrials.gov/ct2/show/NCT03801837?term = macadamia + nut&draw = 2&rank = 1.
| S-EPMC10173088 | biostudies-literature
Project description:ObjectiveThyroid hormones can lower levels of atherogenic lipoproteins, and selenium is important in thyroid hormone homeostasis. We aimed to investigate the effects of a healthy diet associated with the Brazil nut (Bertholletia excelsa) in dyslipidemic and hypertensive patients.MethodsThis study was a randomized, placebo-controlled, double-blind trial. Seventy-seven dyslipidemic and hypertensive patients already receiving lipid-lowering drugs received either a dietary treatment associated with partially defatted Brazil nut flour (13 g/day providing 227,5 μg of selenium/day),or with dyed cassava flour as a placebo. All patients received a personalized dietary guideline with nutritional recommendations for dyslipidemia and hypertension and were followed for 90 days.ResultsThe Brazil nut group showed reductions in total cholesterol (-20.5 ± 61.2 mg/dL, P = 0.02), non HDL-cholesterol (-19.5 ± 61.2 mg/dL, P = 0.02) and Apo A-1 (-10.2 ± 26.7 mg/dL, P = 0.03) without significant alterations in the Apo B/Apo A-1 ratio. The placebo group showed a reduction in FT3 levels (-0.1 ± 0.4, P = 0.03) and increased Lp(a) levels (5.9 ± 18.0 mg/dL, P = 0.02). There were no statistical differences in blood pressure and serum lipids between Brazil nut and placebo group.ConclusionsSupplementation with Brazil nuts seems to favor the maintenance of FT3 levels and contributes to lipemia reduction in hypercholesterolemic and euthyroid patients.Trial registrationClinicalTrials.gov Identifier NCT01990391.
| S-EPMC4488974 | biostudies-literature
Project description:BackgroundThe 2S albumin Ber e 1 is the major allergen in Brazil nuts. Previous findings indicated that the protein alone does not cause an allergenic response in mice, but the addition of components from a Brazil nut lipid fraction were required. Structural details of Ber e 1 may contribute to the understanding of the allergenic properties of the protein and its potential interaction partners.Methodology/principal findingsThe solution structure of recombinant Ber e 1 was solved using NMR spectroscopy and measurements of the protein back bone dynamics at a residue-specific level were extracted using (15)N-spin relaxation. A hydrophobic cavity was identified in the structure of Ber e 1. Using the paramagnetic relaxation enhancement property of Cu(2+) in conjunction with NMR, it was shown that Ber e 1 is able to specifically interact with the divalent copper ion and the binding site was modeled into the structure. The IgE binding region as well as the copper binding site show increased dynamics on both fast ps-ns timescale as well as slower µs-ms timescale.Conclusions/significanceThe overall fold of Ber e 1 is similar to other 2S albumins, but the hydrophobic cavity resembles that of a homologous non-specific lipid transfer protein. Ber e 1 is the first 2S albumin shown to interact with Cu(2+) ions. This Cu(2+) binding has minimal effect on the electrostatic potential on the surface of the protein, but the charge distribution within the hydrophobic cavity is significantly altered. As the hydrophobic cavity is likely to be involved in a putative lipid interaction the Cu(2+) can in turn affect the interaction that is essential to provoke an allergenic response.
| S-EPMC3464261 | biostudies-literature
Project description:Characteristics and outcomes of tree nut (TN) oral food challenges (OFCs) in patients with TN allergy or sensitization alone are poorly studied.To determine the relation between TN sensitization levels and OFC outcomes.Open TN OFCs performed from 2007 through 2015 at a referral center were analyzed to compare outcome based on skin prick test (SPT) wheal size, food-specific immunoglobulin E (sIgE), peanut co-allergy, and TN sensitization only vs TN allergy with sensitization to other TNs. Delayed OFC was defined as longer than 12 months from the time of an sIgE level lower than 2 kUA/L.Overall passage rate was 86% for 156 TN OFCs in 109 patients (54 almond, 28 cashew, 27 walnut, 18 hazelnut, 14 pecan, 13 pistachio, and 2 Brazil nut). Passage rates were 76% (n = 67) in patients with a history of TN allergy who were challenged to another TN to which they were sensitized and 91% (n = 65) in those with TN sensitization only (mean sIgE 1.53 kUA/L; range 0.35-9.14). Passage rates were 89% (n = 110 of 124) for a TN sIgE level lower than 2 kUA/L and 69% (11 of 16) for a TN sIgE level of at least 2 kUA/L. In 44 challenges in patients with peanut allergy and TN co-sensitization, the TN OFC passage rate was 96%. In 41 TN OFCs with a TN SPT wheal size of at least 3 mm, 61% passed, with a mean wheal size of 4.8 mm (range 3-11) in those passing vs 9 mm (range 3-20) in those failing.TN challenges are frequently passed in patients with TN sensitization with or without a history of TN reactivity despite a TN SPT wheal of at least 3 mm or a TN sIgE level of at least 2 kUA/L. Nearly all patients with peanut allergy and TN co-sensitization passed the TN challenge, questioning the clinical relevance of "co-allergy."
| S-EPMC6085138 | biostudies-literature