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1.
An Acad Bras Cienc ; 95(1): e20211348, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37075350

RESUMO

In this study we investigate the niche interaction between the frogs Physalameus cuvieri and Physalaemus kroyeri that occur in syntopy in water bodies of the Atlantic Forest located in the eastern Bahia State, Brazil. We investigated the niche width and overlap in the calling activity time, microhabitat use, diet composition, advertisement call, and body size. Both species preferred the same substrate and calling substrate categories, and showed low niche width values and high spatial niche overlap values. The pseudocommunity analysis revealed the absence of competition in space use. Ants and termites were the most important items in the diet of both species with the pseudocommunity analysis indicating an absence of competition in the diet. The two species demonstrate a greater similarity in body proportions and a high overlap in the calling activity time. However, they showed divergence in acoustic parameters, especially in the dominant frequency and call duration. Our results reinforce the role of advertisement call as a relevant attribute for anuran coexistence and highlight the importance of analyzing the various axes of the multidimensional niche for the most reliable description of the existence and magnitude of niche partitioning.


Assuntos
Anuros , Florestas , Animais , Brasil , Dieta , Acústica
2.
Proc Natl Acad Sci U S A ; 116(26): 12907-12912, 2019 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-31186360

RESUMO

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.


Assuntos
Biomassa , Mudança Climática , Oceanos e Mares , Animais , Organismos Aquáticos/fisiologia , Pesqueiros/estatística & dados numéricos , Peixes/fisiologia , Cadeia Alimentar , Modelos Teóricos
3.
Analyst ; 139(11): 2842-9, 2014 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-24733185

RESUMO

A simple and highly selective electrochemical method was developed for the single or simultaneous determination of dopamine (DA) and epinephrine (EP) in human body fluids using a glassy carbon electrode modified with nickel oxide nanoparticles and carbon nanotubes within a dihexadecylphosphate film using square-wave voltammetry (SWV) or differential-pulse voltammetry (DPV). Using DPV with the proposed electrode, a separation of ca. 360 mV between the peak reduction potentials of DA and EP present in binary mixtures was obtained. The analytical curves for the simultaneous determination of dopamine and epinephrine showed an excellent linear response, ranging from 7.0 × 10(-8) to 4.8 × 10(-6) and 3.0 × 10(-7) to 9.5 × 10(-6) mol L(-1) for DA and EP, respectively. The detection limits for the simultaneous determination of DA and EP were 5.0 × 10(-8) mol L(-1) and 8.2 × 10(-8) mol L(-1), respectively. The proposed method was successfully applied in the simultaneous determination of these analytes in human body fluid samples of cerebrospinal fluid, human serum and lung fluid.


Assuntos
Líquidos Corporais/química , Dopamina/análise , Eletrodos , Epinefrina/análise , Nanopartículas Metálicas , Nanotubos de Carbono , Níquel/química , Organofosfatos/química , Humanos , Microscopia Eletrônica de Varredura
4.
Sci Total Environ ; 877: 162754, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-36921858

RESUMO

Non-native species are spreading at an unprecedented rate over large spatial scales, with global environmental change and growth in commerce providing novel opportunities for range expansion. Assessing the pattern and rate of spread is key to the development of strategies for safeguarding against future invasions and efficiently managing existing ones. Such assessments often depend on spatial distribution data from online repositories, which can be spatially biased, imprecise, and lacking in quantity. Here, the influence of disparities between occurrence records from online data repositories and what is known of the invasion history from peer-reviewed published literature on non-native species range expansion was evaluated using 6693 records of the Pacific oyster, Magallana gigas (Thunberg, 1793), spanning 56 years of its invasion in Europe. Two measures of spread were calculated: maximum rate of spread (distance from introduction site over time) and accumulated area (spatial expansion). Results suggest that despite discrepancies between online and peer-reviewed data sources, including a paucity of records from the early invasion history in online repositories, the use of either source does not result in significantly different estimates of spread. Our study significantly improves our understanding of the European distribution of M. gigas and suggests that a combination of short- and long-range dispersal drives range expansions. More widely, our approach provides a framework for comparison of online occurrence records and invasion histories as documented in the peer-reviewed literature, allowing critical evaluation of both data sources and improving our understanding of invasion dynamics significantly.


Assuntos
Big Data , Ostreidae , Animais , Europa (Continente) , Espécies Introduzidas
5.
Polymers (Basel) ; 15(11)2023 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-37299359

RESUMO

Bio-based polyols were obtained from the thermochemical liquefaction of two biomass feedstocks, pinewood and Stipa tenacissima, with conversion rates varying between 71.9 and 79.3 wt.%, and comprehensively characterized. They exhibit phenolic and aliphatic moieties displaying hydroxyl (OH) functional groups, as confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. The biopolyols obtained were successfully employed as a green raw material to produce bio-based polyurethane (BioPU) coatings on carbon steel substrates, using, as an isocyanate source, a commercial bio-based polyisocyanate-Desmodur® Eco N7300. The BioPU coatings were analyzed in terms of chemical structure, the extent of the reaction of the isocyanate species, thermal stability, hydrophobicity, and adhesion strength. They show moderate thermal stability at temperatures up to 100 °C, and a mild hydrophobicity, displaying contact angles between 68° and 86°. The adhesion tests reveal similar pull-off strength values (ca. 2.2 MPa) for the BioPU either prepared with pinewood and Stipa-derived biopolyols (BPUI and BPUII). Electrochemical impedance spectroscopy (EIS) measurements were carried out on the coated substrates for 60 days in 0.05 M NaCl solution. Good corrosion protection properties were achieved for the coatings, with particular emphasis on the coating prepared with the pinewood-derived polyol, which exhibited a low-frequency impedance modulus normalized for the coating thickness of 6.1 × 1010 Ω cm at the end of the 60 days test, three times higher than for coatings prepared with Stipa-derived biopolyols. The produced BioPU formulations show great potential for application as coatings, and for further modification with bio-based fillers and corrosion inhibitors.

6.
PLoS One ; 17(2): e0263786, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35143577

RESUMO

This study investigated the effect of five post-weaning supplementation strategies and two weaning weight groups on long-term growth, puberty and pregnancy percentage of Brahman crossbred heifers. Early-weaned (118 ± 6 kg liveweight) and normally-weaned (183 ± 6 kg liveweight) heifers were allocated to group pens (n = 4 and n = 5/pen for early- and normally-weaned respectively) and offered one of five levels of post-weaning protein supplementation: 0, 1, 2.5, 5 and 10 g of supplement/kg liveweight.day with ad libitum access to a low quality sabi grass (Urochloa mosambicensis) hay during the first dry season (169 days) after weaning. After the post-weaning supplementation period, all heifers grazed the same pastures as a single mob until the end of the experiment and were exposed to fertile bulls from January to May 2016. During the first dry season, supplement intake had a positive linear effect on liveweight gain and hip width gain with no difference in the response between weaning groups. Overall, heifers with higher supplement intakes (i.e. 5 and 10 g/kg) had higher hip height gain (P < 0.005), hip width gain (P < 0.001), body condition score (P < 0.001), and concentration of insulin-like growth factor-1 (P = 0.001), triiodothyronine (P = 0.04) and insulin (P = 0.05) in plasma compared to unsupplemented heifers. These changes resulted in thicker proliferative and hypertrophic zones (both P = 0.03) of the tuber coxae growth plate, larger diameter of terminal hypertrophic chondrocytes (both P = 0.004) at the end of the post-weaning supplementation period when comparing the highest level of supplementation with unsupplemented group. Unsupplemented heifers from both weaning weight groups demonstrated compensatory liveweight gain over the first wet season while evidence of catch-up growth in skeletal dimensions was observed in the second wet season. The main determining factor for pregnancy status of two-year-old Brahman crossbred heifers was pre-mating liveweight (P < 0.001), the pre-mating liveweight was in turn affected by post-weaning supplementation (P = 0.02) or weaning weight group (P < 0.001). This study further demonstrated the positive relationship between premating weight and the occurrence of pregnancy, with an approximate 300 kg pre-mating liveweight required to achieve approximately 80% (67.1-90.3% for a 95% confidence interval) probability of pregnancy in two-year-old Brahman crossbred heifers mated for 4 months.


Assuntos
Ração Animal/análise , Peso Corporal/fisiologia , Reprodução/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Bovinos , Hibridização Genética , Desmame
7.
J Pharm Biomed Anal ; 221: 115032, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36152488

RESUMO

The outstanding electronic properties of carbon black (CB) and its economic advantages have fueled its application as nanostructured electrode material for the development of new electrochemical sensors and biosensors. CB-based electrochemical sensing devices have been found to exhibit high surface area, fast charge transfer kinetics, and excellent functionalization. In the present work, we set forth a comprehensive review of the recent advances made in the development and application of CB-based electrochemical devices for pharmaceutical and biomedical analyses - from quantitative monitoring of drug formulations to clinical diagnoses - and the underlying challenges and constraints that need to be overcome. We also present a thorough discussion about the strategies and techniques employed in the development of new electrochemical sensing platforms and in the enhancement of their analytical properties and biocompatibility for anchoring active biomolecules, as well as the combination of these sensing devices with other materials aiming at boosting the performance and efficiency of the sensors.


Assuntos
Técnicas Biossensoriais , Nanoestruturas , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Nanoestruturas/química , Preparações Farmacêuticas , Fuligem
8.
Urology ; 154: e17-e18, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33891926

RESUMO

A case report of a 51-year-old man with left renal tumor and level II vena cava tumor thrombus (thrombus extending >2 cm above the renal vein, but below the hepatic veins) in a rare anatomical variant of renal vein. In nonmetastatic patients, aggressive surgical resection is widely accepted as the standard management option, but some doubts about the best practice in these patients are relevant. Surgical approach on those patients is a challenge for the surgeons, and anatomical variants make the procedure even more difficulty. These patients should be referring to a tertiary center because of the potential perioperative complexity.


Assuntos
Neoplasias Renais/patologia , Células Neoplásicas Circulantes , Veias Renais/anormalidades , Humanos , Masculino , Pessoa de Meia-Idade
9.
PLoS One ; 16(2): e0247718, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33630953

RESUMO

The objective of this study was to investigate the effect of diet crude protein (CP) content and metabolisable energy (ME) intake on skeletal growth and associated parameters of growing steers prior to and during compensatory growth in weight and catch-up growth in skeletal elongation. The experiment was a factorial design with two cattle genotypes [Brahman crossbred (BX, 178 ± 6 kg) and Holstein-Friesian (HF, 230 ± 34 kg)] and three nutritional treatments; high CP content and high ME intake (HCP-HME), high CP content and low ME intake (HCP-LME) and low CP content and low ME intake (LCP-LME) with the ME intake of HCP-LME matched to that of LCP-LME. Nutritional treatments were imposed over a 103 d period (Phase 1), and after this, all steers were offered ad libitum access to the HCP-HME nutritional treatment for 100 d (Phase 2). Steers fed the high CP content treatment with a low ME intake, showed higher hip height gain (P = 0.04), larger terminal hypertrophic chondrocytes (P = 0.02) and a higher concentration of total triiodothyronine in plasma (P = 0.01) than steers with the same ME intake of the low CP content treatment. In addition, the low CP treatment resulted in significant decreases in bone volume (P = 0.03), bone surface area (P = 0.03) and the concentration of bone-specific alkaline phosphatase in plasma (P < 0.001) compared to steers fed the HCP-HME treatment. A significant interaction between genotype and nutritional treatment existed for the concentration of thyroxine (T4) in plasma where HF steers fed LCP-LME had a lower T4 concentration in plasma (P = 0.05) than BX steers. All steers with a restricted ME intake during Phase 1 demonstrated compensatory growth during Phase 2. However, HF steers fed the LCP treatment during Phase 1 showed a tendency (P = 0.07) for a greater LWG during Phase 2 without any increase in dry matter intake. Results observed at the growth plate and hip height growth suggest that catch-up growth in cattle may also be explained by the growth plate senescence hypothesis. Contrary to our initial hypothesis, the results demonstrate that greater CP intake during ME restriction does not increase compensatory gain in cattle during re-alimentation.


Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Osso e Ossos/metabolismo , Dieta Rica em Proteínas/veterinária , Proteínas Alimentares/administração & dosagem , Ingestão de Energia , Animais , Desenvolvimento Ósseo , Bovinos , Metabolismo Energético , Genótipo , Masculino
10.
Zookeys ; 1060: 125-153, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34629926

RESUMO

A list of amphibian and reptile species that occur in open and forested areas of the Atlantic Forest in the municipality of Cruz das Almas, in the Recôncavo Baiano, eastern Brazil is presented. Field sampling occurred between January 2015 to March 2019, totalling 117 samples distributed in three areas: Parque Florestal Mata de Cazuzinha, Mata da Cascalheira, and Riacho do Machado. A total of 1,848 individuals of 69 species (31 anurans, 14 lizards, 19 snakes, two amphisbaenians, and three testudines) was recorded. Additionally, one individual of Ophiodesstriatus was found in Mata da Cascalheira after the end of sampling, totalling 15 lizard species and 70 herpetofaunal species. The prevalence of open-area species and the presence of Phyllopezuslutzae, Diploglossuslessonae, and Dryadosauranordestina in interior forest patches are discussed. Additionally, a new record of the invasive terrapin Trachemysdorbigni in the State of Bahia is reported.

11.
Anal Chim Acta ; 1139: 198-221, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33190704

RESUMO

The detection of phenolic compounds is relevant not only for their possible benefits to human health but also for their role as chemical pollutants, including as endocrine disruptors. The required monitoring of such compounds on-site or in field analysis can be performed with electrochemical biosensors made with polyphenol oxidases (PPO). In this review, we describe biosensors containing the oxidases tyrosinase and laccase, in addition to crude extracts and tissues from plants as enzyme sources. From the survey in the literature, we found that significant advances to obtain sensitive, robust biosensors arise from the synergy reached with a diversity of nanomaterials employed in the matrix. These nanomaterials are mostly metallic nanoparticles and carbon nanostructures, which offer a suitable environment to preserve the activity of the enzymes and enhance electron transport. Besides presenting a summary of contributions to electrochemical biosensors containing PPOs in the last five years, we discuss the trends and challenges to take these biosensors to the market, especially for biomedical applications.


Assuntos
Técnicas Biossensoriais , Monofenol Mono-Oxigenase , Nanoestruturas , Carbono , Técnicas Eletroquímicas , Lacase
12.
ACS Nano ; 12(8): 8467-8476, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-30011370

RESUMO

The catalytic performance and optical properties of bimetallic nanoparticles critically depend on the atomic distribution of the two metals in the nanoparticles. However, at elevated temperatures, during light-induced heating, or during catalysis, atomic redistribution can occur. Measuring such metal redistribution in situ is challenging, and a single experimental technique does not suffice. Furthermore, the availability of a well-defined nanoparticle system has been an obstacle for a systematic investigation of the key factors governing the atomic redistribution. In this study, we follow metal redistribution in precisely tunable, single-crystalline Au-core, Ag-shell nanorods in situ, both at a single particle and an ensemble-averaged level, by combining in situ transmission electron spectroscopy with in situ extended X-ray absorption fine structure validated by ex situ measurements. We show that the kinetics of atomic redistribution in Au-Ag nanoparticles depend on the metal composition and particle volume, such that a higher Ag content or a larger particle size led to significantly slower metal redistribution. We developed a simple theoretical model based on Fick's first law that can correctly predict the composition- and size-dependent alloying behavior in Au-Ag nanoparticles, as observed experimentally.

14.
ACS Catal ; 7(9): 5594-5603, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28944089

RESUMO

Supported gold nanoparticles are highly selective catalysts for a range of both liquid-phase and gas-phase hydrogenation reactions. However, little is known about their stability during gas-phase catalysis and the influence of the support thereon. We report on the activity, selectivity, and stability of 2-4 nm Au nanoparticulate catalysts, supported on either TiO2 or SiO2, for the hydrogenation of 0.3% butadiene in the presence of 30% propene. Direct comparison of the stability of the Au catalysts was possible as they were prepared via the same method but on different supports. At full conversion of butadiene, only 0.1% of the propene was converted for both supported catalysts, demonstrating their high selectivity. The TiO2-supported catalysts showed a steady loss of activity, which was recovered by heating in air. We demonstrated that the deactivation was not caused by significant metal particle growth or strong metal-support interaction, but rather, it is related to the deposition of carbonaceous species under reaction conditions. In contrast, all the SiO2-supported catalysts were highly stable, with very limited formation of carbonaceous deposits. It shows that SiO2-supported catalysts, despite their 2-3 times lower initial activities, clearly outperform TiO2-supported catalysts within a day of run time.

15.
J Colloid Interface Sci ; 296(2): 465-71, 2006 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-16359695

RESUMO

The adsorption isotherms of Cr(VI) on kaolinite, montmorillonite, and alumina were adequately treated with Langmuir model showing behavior characteristic of single-layer adsorption. The efficiency of the adsorbents in removing Cr(VI) from water follows the order alumina > kaolinite > montmorillonite > silica. Speciation studies indicate that hydrogen chromate ions were the major adsorbed species and simultaneous adsorption of dichromate ion occurred at concentrations greater than approximately 10(-3) mol L(-1). It is most probable that the mechanism of adsorption of the hydrogen chromate ion at the surface of alumina is predominantly electrostatic adsorption, with outer sphere complex formation.

16.
ACS Appl Mater Interfaces ; 6(23): 21086-92, 2014 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-25402230

RESUMO

Porous diamond-like carbon (DLC) electrodes have been prepared, and their electrochemical performance was explored. For electrode preparation, a thin DLC film was deposited onto a densely packed forest of highly porous, vertically aligned multiwalled carbon nanotubes (VACNT). DLC deposition caused the tips of the carbon nanotubes to clump together to form a microstructured surface with an enlarged surface area. DLC:VACNT electrodes show fast charge transfer, which is promising for several electrochemical applications, including electroanalysis. DLC:VACNT electrodes were applied to the determination of targeted molecules such as dopamine (DA) and epinephrine (EP), which are neurotransmitters/hormones, and acetaminophen (AC), an endocrine disruptor. Using simple and low-cost techniques, such as cyclic voltammetry, analytical curves in the concentration range from 10 to 100 µmol L(-1) were obtained and excellent analytical parameters achieved, including high analytical sensitivity, good response stability, and low limits of detection of 2.9, 4.5, and 2.3 µmol L(-1) for DA, EP, and AC, respectively.


Assuntos
Acetaminofen/isolamento & purificação , Dopamina/isolamento & purificação , Epinefrina/isolamento & purificação , Nanotubos de Carbono/química , Acetaminofen/química , Técnicas Biossensoriais/métodos , Dopamina/química , Eletrodos , Disruptores Endócrinos/química , Disruptores Endócrinos/isolamento & purificação , Epinefrina/química , Humanos , Porosidade , Propriedades de Superfície
17.
Sci Rep ; 4: 5766, 2014 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-25042537

RESUMO

Gold-palladium (AuPd) nanoparticles have shown significantly enhanced activity relative to monometallic Au and Pd catalysts. Knowledge of composition and metal domain distributions is crucial to understanding activity and selectivity, but these parameters are difficult to ascertain in catalytic experiments that have primarily been devoted to equimolar nanoparticles. Here, we report AuPd nanoparticles of varying Au:Pd molar ratios that were prepared by a seed growth method. The selective oxidation of benzyl alcohol was used as a model reaction to study catalytic activity and selectivity changes that occurred after varying the composition of Pd in bimetallic catalysts. We observed a remarkable increase in catalytic conversion when using a 10:1 Au:Pd molar ratio. This composition corresponds to the amount of Pd necessary to cover the existing Au cores with a monolayer of Pd as a full-shell cluster. The key to increased catalytic activity derives from the balance between the number of active sites and the ease of product desorption. According to density functional theory calculations, both parameters are extremely sensitive to the Pd content resulting in the volcano-like activity observed.

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