► Data on crop productivity after biochar application to soils quantitatively analysed. ► Grand mean effect is 10% increase in crop productivity. ► Large variation in data allows limited but useful ...insights in causative mechanisms. ► Auxiliary, temporal and spatial data is not currently sufficiently representative. ► Strategic research and full reporting on statistics and auxiliary data are needed.
Increased crop yield is a commonly reported benefit of adding biochar to soils. However, experimental results are variable and dependent on the experimental set-up, soil properties and conditions, while causative mechanisms are yet to be fully elucidated. A statistical meta-analysis was undertaken with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass). Results showed an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%. However, the mean results for each analysis performed within the meta-analysis covered a wide range (from −28% to 39%). The greatest (positive) effects with regard to soil analyses were seen in acidic (14%) and neutral pH soils (13%), and in soils with a coarse (10%) or medium texture (13%). This suggests that two of the main mechanisms for yield increase may be a liming effect and an improved water holding capacity of the soil, along with improved crop nutrient availability. The greatest positive result was seen in biochar applications at a rate of 100
t
ha
−1 (39%). Of the biochar feedstocks considered and in relation to crop productivity, poultry litter showed the strongest (significant) positive effect (28%), in contrast to biosolids, which were the only feedstock showing a statistically significant negative effect (−28%). However, many auxiliary data sets (i.e. information concerning co-variables) are incomplete and the full range of relevant soil types, as well as environmental and management conditions are yet to be investigated. Furthermore, only short-term studies limited to periods of 1 to 2 years are currently available. This paper highlights the need for a strategic research effort, to allow elucidation of mechanisms, differentiated by environmental and management factors and to include studies over longer time frames.
Gold nanoparticles (AuNPs) are highlighted due to their low toxicity, compatibility with the human body, high surface area to volume ratio, and surfaces that can be easily modified with ligands. ...Biosynthesis of AuNPs using plant extract is considered a simple, low-cost, and eco-friendly approach. Brazilian Red Propolis (BRP), a product of bees, exhibits anti-inflammatory, anti-tumor, antioxidant, and antimicrobial activities. Here, we described the biosynthesis of AuNPs using BRP extract (AuNP
) and its fractions (AuNP
, AuNP
, AuNP
) and evaluated their structural properties and their potential against microorganisms and cancer cells. AuNPs showed a surface plasmon resonance (SPR) band at 535 nm. The sizes and morphologies were influenced by the BRP sample used in the reaction. FTIR and TGA revealed the involvement of bioactive compounds from BRP extract or its fractions in the synthesis and stabilization of AuNPs. AuNP
and AuNP
exhibited antimicrobial activities against all strains tested, showing their efficacy as antimicrobial agents to treat infectious diseases. AuNPs showed dose-dependent cytotoxic activity both in T24 and PC-3 cells. AuNP
and AuNP
exhibited the highest in vitro cytotoxic effect. Also, the cytotoxicity of biogenic nanoparticles was induced by mechanisms associated with apoptosis. The results highlight a potential low-cost green method using Brazilian red propolis to synthesize AuNPs, which demonstrated significant biological properties.
This paper reports a dynamic causal modeling study of electrocorticographic (ECoG) data that addresses functional asymmetries between forward and backward connections in the visual cortical ...hierarchy. Specifically, we ask whether forward connections employ gamma-band frequencies, while backward connections preferentially use lower (beta-band) frequencies. We addressed this question by modeling empirical cross spectra using a neural mass model equipped with superficial and deep pyramidal cell populations—that model the source of forward and backward connections, respectively. This enabled us to reconstruct the transfer functions and associated spectra of specific subpopulations within cortical sources. We first established that Bayesian model comparison was able to discriminate between forward and backward connections, defined in terms of their cells of origin. We then confirmed that model selection was able to identify extrastriate (V4) sources as being hierarchically higher than early visual (V1) sources. Finally, an examination of the auto spectra and transfer functions associated with superficial and deep pyramidal cells confirmed that forward connections employed predominantly higher (gamma) frequencies, while backward connections were mediated by lower (alpha/beta) frequencies. We discuss these findings in relation to current views about alpha, beta, and gamma oscillations and predictive coding in the brain.
•We briefly review evidence for canonical microcircuits (CMC) and predictive coding.•This evidence is incorporated into a novel Dynamic Causal Model (DCM).•We model observed cross-spectral densities from monkey visual cortex (V1 and V4).•We establish the face and predictive validity of this new DCM.•Gamma rhythms subserve feedforward, and alpha/beta rhythms feedback influences.
Use of organic–inorganic hybrid sol–gel thin films is recently reported among the most promising approaches for the replacement of chromate based pre-treatment methods for high strength structural ...aluminium parts.
To be applied in the aerospace industry, pre-treatments have to meet the demanding requirements and must be compatible to state of the art paint systems. The addition of inhibitive species is desirable for the active corrosion protection and the prevention of sub-surface migration at defect sites of the coating.
In the present work hybrid films were produced by the controllable sol–gel route. Corrosion inhibitors were incorporated to the coatings in order to provide active protective effect. The barrier properties and the active corrosion protection on AA2024-T3 have been studied by Electrochemical Impedance Spectroscopy and Scanning Vibrating Electrode Technique. The obtained results were proven by conventional accelerated tests such as neutral salt spray test confirming validity of the mentioned electrochemical techniques for the evaluation of protection efficiency of hybrid sol–gel films.
The addition of inhibitors to sol–gel coatings in most cases leads to an improvement of the active corrosion protection but on the other hand it may negatively influences the barrier properties of the films. Therefore, encapsulation of the inhibiting compounds is beneficial in order to combine the good barrier function of the coating with the corrosion mitigating effect of the inhibitors.
Baccharis trimera (Less) DC. (Asteraceae), popularly known in Brazil as “carqueja”, have been used in folk medicine to treat gastrointestinal, hepatic and renal diseases, and inflammatory processes ...as rheumatism.
To evaluate the in vitro and in vivo toxicological effects of anti-inflammatory Baccharis trimera aqueous extract and fractions.
Aqueous extract of Baccharis trimera (AEBt) was produced by infusion in boiling water. After lyophylization AEBt was extracted with 80% ethanol, originating the ethanolic supernatant fraction (EFBt) and the aqueous sediment fraction (AFBt). Anti-inflammatory properties of AEBt, EFBt or AFBt (3, 30 or 300μg/kg b.w.) were evaluated by the carrageenan-induced mouse paw edema using indomethacin (10mg/kg) as positive control. The growth of rat hepatoma cells (HTC) and human embryo kidney epithelial cells (HEK) was determined by protein staining assay. Cytotoxicity was assayed by the tetrazolium salt (MTT) reduction. Cyclosporin was used as reference cytotoxic drug for spleen cells and doxorubicin for HTC and HEK cells. For in vivo toxicological evaluation SW male mice were daily and oral (gavage) treated with extract/fractions at 4.2mg/kg or 42mg/kg during 15 days. After treatment liver or kidney cells were submitted to comet assay to determine the DNA damage index, and the glutathione S-transferase activity was assayed towards ETHA (class Pi) and CDNB (several classes). Mutagenicity was evaluated by the Ames test using Salmonella typhimurium strains TA97, TA98, TA100, and TA102.
The anti-inflammatory effects of EFBt were higher than those of AEBt or AFBt. Mice treatment (3–300μg/kg) with AFBt reduced the paw edema (3h) at lower levels (29.2–37.3%; P<0.01), than those observed for AEBt (44.7–54.2%; P<0.001), EFBt (49.3–58.2%; P<0.001) or indomethacin (64.6%, P<0.001, 10mg/kg). The growth of kidney cells (HEK) was inhibited by AEBt (IC50 182.6μg/ml), EFBt (IC50 78.1μg/ml) and AFBt (IC50 86.2μg/ml), with lower effects on HTC hepatic cell (IC50 308.8μg/ml, 396.5μg/ml and 167.9μg/ml, respectively). As evaluated by MTT test, AFBt exhibited cytotoxicity for HEK cells (IC50 372.5μg/ml), but none for HTC ones; by the way, AFBt stimulated spleen cells (EC50 2.2μg/ml) while cyclosporine, a cytotoxic reference drug inhibited them with IC50 of 0.42μg/ml; the IC50 for doxorubicin for HEK and HTC cells was 0.28μg/ml and 14.4μg/ml, respectively, at 96h. No mutagenic potential was observed. Mice treatment with AEBt or AFBt at 42mg/kg for 15 days altered the kidney relative weight, but not at 4.2mg/kg. Baccharis trimera did not change liver, spleen or popliteal lymph node relative weight. DNA damage index of kidney cells was observed on mice treated with AEBt/AFBt, but not on animals treated with EFBt, while DNA lesions were detected on liver cells only after AFBt treatment. The general activities of hepatic GST and Pi GST were reduced by EFBt and AFBt treatment, respectively.
Baccharis trimera did not show mutagenicity, inhibited the GST activity, a hepatic detoxification enzyme, and induced in vivo (genotoxicity) and in vitro toxicological effects to kidney cells.
Legislative inertia fails Brazil's Cerrado Bastos, Maria C C; Pestana, Mateus C A; Oliveira, Rafael F
Science (American Association for the Advancement of Science),
12/2023, Volume:
382, Issue:
6674
Journal Article
Abstract Objectives Analyze the effect of varnishes containing xylitol compared to commercial fluoridated varnishes on the remineralization of artificial enamel caries lesions in situ. Methods Twenty ...subjects took part in this crossover, double-blind study performed in four phases of 5 days each. Each subject worn palatal appliances containing four predemineralized bovine enamel specimens. Artificial caries lesions were produced by immersion in 30 ml of lactic acid buffer containing 3 mM CaCl2 ·2H2 O, 3 mM KH2 PO4 , 6 μM tetraetil metil diphosphanate (pH 5.0) for 6 days. The specimens in each subject were treated once with the following varnishes: 20% xylitol (experimental); Duofluorid™ (6% NaF, 6% CaF2 ), Duraphat™ (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6 h. Fifteen subjects were able to finish all phases. The enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analyzed by Friedmann and Dunn’s tests test (p < 0.05). Results Enamel surface remineralization was significantly increased by Duraphat™, Duofluorid™ and 20% xylitol formulations. Significant subsurface mineral remineralization could also be seen for the experimental and commercial varnishes, except for Duraphat™, when the parameter “lesion depth” was considered. Conclusions 20% xylitol varnish seem to be a promising alternative to increase surface and subsurface remineralization of artificial caries lesions in situ . Clinical significance: effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in situ, which should be confirmed by clinical studies.
In this work, layered double hydroxide (LDH) conversion films were grown on aluminium alloy 2024 substrates. The effect of experimental conditions on the growth of LDH conversion films, including ...concentration of reactants and presence of corrosion inhibitor, was investigated. The protective performance provided by LDH films was assessed by electrochemical impedance spectroscopy (EIS), and rationalised in terms of structural and morphological characteristics surveyed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that corrosion protection increases when corrosion inhibitors (vanadates) are intercalated in LDHs and dilute solutions of Zn2+ are used to grow LDHs.
•Ce–Cu, Ce–Ni and Ce–Co oxides were prepared by exotemplating and evaporation methods.•The materials obtained were tested as catalysts for ethyl acetate oxidation to CO2.•Samples prepared by ...evaporation were more active than those prepared by exotemplating.•Catalytic activity depends on the amount of Ce, calcination temperature and sample reducibility.•The most active samples were Ce–Co and Ce–Cu oxides while Ce–Ni were the least active.
Cerium-containing mixed oxides (Ce–Cu, Ce–Ni and Ce–Co) were synthesized by exotemplating and evaporation methods. A carbon xerogel was used as template in the exotemplating procedure. The evaporation method was based on thermal decomposition of oxalates. Samples were characterized by thermogravimetry and differential scanning calorimetry, N2 adsorption at −196°C, temperature programmed reduction, scanning electron microscopy and X-ray diffraction. The materials obtained were tested as catalysts for ethyl acetate oxidation, as a model volatile organic compound. In general, materials with larger surface areas were achieved by exotemplating. Apart from the Ce–Cu oxides, the samples with a molar ratio of 1:2 had larger surface areas than the corresponding 1:1 materials. Smaller crystallite sizes were obtained with calcinations at lower temperatures. Materials prepared by evaporation were more active than those prepared by exotemplating and the 1:1 ratio was more favourable than 1:2. Full conversion of ethyl acetate was achieved at much lower temperatures with the mixed metal oxides, in comparison to single oxides. The most active materials were Ce–Co and Ce–Cu oxides. Ce–Ni oxide samples were the least active. Catalytic activity seems to be related not only with surface area, but also with the amount of Ce contained in the samples, calcination temperature (which influenced the particle size) and the reducibility of the catalysts.
Dipeptidyl peptidase 4 (DPP4) regulates various physiological pathways and has a pivotal role in glucose homeostasis. The objective of this study was to verify the association of a haplotype ...constituted by two single nucleotide polymorphisms (rs2268894 and rs6741949) in the DPP4 gene with type 2 diabetes mellitus (T2DM) and fasting glycemia-related variables in a sample of Brazilian older adults, taking serum levels and enzymatic activity of DPP4 into account. Clinical, biochemical, and anthropometric characteristics as well as DPP4 serum levels and enzymatic activity were determined in 800 elderly (greater than or equal to 60 years old) individuals. Assessment of polymorphic sites was performed by real-time PCR whereas haplotypes were inferred from genotypic frequencies. Statistical analyses compared measures and proportions according to T2DM diagnosis and DPP4 haplotypic groups. The most common haplotype consisted of the T-rs2268894/G- rs6741949 string, which was 20% more frequent among non-diabetics. Considering non-diabetic patients alone, carriers of the T/G haplotype had significantly lower levels of blood glucose, insulin, HOMA-IR index, and DPP4 activity. Among diabetic patients, the T/G haplotype was associated with lower DPP4 levels whereas glycemic scores were not affected by allelic variants. Our results suggested that the genetic architecture of DPP4 affects the glycemic profile and DPP4 serum levels and activity among elderly individuals according to the presence or absence of T2DM, with a possible implication of the T/G haplotype to the risk of T2DM onset. Key words: Dipeptidyl peptidase 4; Type 2 diabetes mellitus; Elderly; Glycemia
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