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1.
Braz J Biol ; 84: e279536, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38597531

RESUMO

Planting with higher density in sugarcane is one of the practices used to overcome low productivity. However, this planting material is equivalent to 25% of the total cost of production, being one of the main expenses for cultivation. In this sense, the present work aims to evaluate the productivity and economic viability of sugarcane as a function of planting density. The experiment was carried out at Usina Monte Alegre in the municipality of Mamanguape, Paraíba, Brazil, from March 2021 to January 2022 with the variety RB92579. Seven planting density were studied: T1: 7 gems m-1, T2: 10 gems m-1, T3: 12 gems m-1, T4: 11 gems m-1, T5: 15 gems m-1, T6: 17 gems m-1, T7: 24 gems m-1, in randomized blocks with four replications. Growth, productivity and economic viability were evaluated. The highest productivity of cane and sugar, 77.69 ton ha-1 and 10.390 ton ha-1, respectively, was with planting density of 17 and 24 gems-1. While the minimum productivity of cane (61.313 ton ha-1) and sugar (7.924 ton ha-1) was recorded at sowing density of 7 and 11 gems-1. However, cultivation density with 7 and 10 gems m-1 were the ones that provided the highest profitability around 50%, followed by density of 12, 15 and 17 gems m-1 with an average of 45% profit and 11 and 24 gems m-1 with the lowest proportion of profit on average 38%. The cultivation with 17 gems m-1 of cane provides in cane-plant, variety RB92579, greater productivity with a profit rate of 45%, being the most suitable.


Assuntos
Saccharum , Açúcares , Brasil
2.
Braz J Biol ; 84: e278004, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38511776

RESUMO

In this study, our objective was to conduct a comprehensive phytochemical analysis, determine toxicity levels, and assess the antioxidant and antimicrobial properties of extracts derived from the leaves of Dipteryx alata Vogel, a native species of the Brazilian cerrado flora. Three distinct extracts were prepared utilizing assisted ultrasound and the Soxhlet apparatus, namely, Ultrasound Crude Extract (UCE), Soxhlet Crude Extract (SCE), and the Soxhlet Ethanol Extract (SEE). The phytochemical analysis revealed the presence of flavonoids, tannins, phytosterols, and saponins in all extracts. Additionally, alkaloids were specifically identified in the SCE and SEE extracts. In the analysis using LC-DAD, the compounds gallic acid, rutin, quercetin, luteolin and kampefrol were determined in higher concentrations in the SCE, followed by the SEE and UCE, respectively. The GC-MS analysis revealed the presence of campesterol, stigmasterol and ß-sitosterol in all extracts, with UCE and SCE showing a higher concentration of ß-sitosterol. SCE showed the highest concentration of all identified compounds. In the analysis of antioxidant activity by DPPH• and ABTS•+, SEE showed greater efficiency (IC50 = 2.98 ± 2.92 and 6.57 ± 0.89 µg/mL, respectively). In the toxicity test with Allium cepa, all extracts stimulated root growth at 50 g/mL; UCE and SEE stimulated root growth at 250 g/mL; and SEE inhibited root growth at 750 g/mL. In the Artemia salina toxicity, all extracts were non-toxic. Antibacterial activity was identified in the microorganisms S. aureus and S. mutans; however, the extracts did not show antifungal action against the strain of C. albicans. The extracts of D. alata have therapeutic potential for applicability in dentistry.


Assuntos
Anti-Infecciosos , Dipteryx , Antioxidantes/química , Extratos Vegetais/química , Staphylococcus aureus , Compostos Fitoquímicos/análise , Anti-Infecciosos/toxicidade , Etanol
3.
Braz J Biol ; 83: e270316, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37162094

RESUMO

Ganoderma lucidum is a medicinal mushroom widely recognized as a source of biomolecules with pharmacological properties, however, little is known about the factors that influence the synthesis of bioactive proteins by this fungus when cultivated under submerged fermentation. The objective of this work was to evaluate the production of mycelial biomass and intracellular proteases and protease inhibitors by G. lucidum cultivated under different submerged fermentation conditions. The cultivation was carried out in a medium composed of glucose (10 or 20 g.L-1), soy peptone (2.5 or 5 g.L-1) and yeast extract (5 g.L-1), with incubation under agitation (120 rpm) and non-agitation, totaling 8 experimental conditions. Biomass production was determined from the dry weight, while glucose consumption was estimated by quantification of reducing sugars. The proteins were extracted in NaCl (0.15 M), and the protein extracts were submitted to protein quantification by the Bradford method, total proteolytic activity using azocasein, caseinolytic and fibrinolytic activity in Petri dishes, activity of serine (trypsin and chymotrypsin) and cysteine (papain) protease inhibitors. Cultivation in agitated condition showed higher biomass production with a maximum value of 7 g.L-1, in addition to higher activities of trypsin, chymotrypsin and papain inhibitors, with 154 IU.mg-1, 153 IU.mg-1 e 343 IU.mg-1 of protein, respectively. The non-agitated condition showed a greater potential for obtaining proteins, total proteases, caseinolytic and fibrinolytic enzymes, with maximum values of 433 mg.g-1 of extract, 71 U.mL-1 of extract, 63.62 mm2 and 50.27 mm2, respectively. Thus, a medium composed of soy peptone, yest extract and glucose in a 1:2:4 proportion is recommended, under agitation to produce protease inhibitors, and the non-agitated condition when the target is, mainly caseinolytic and fibrinolytic enzymes.


Assuntos
Peptídeo Hidrolases , Reishi , Fermentação , Inibidores de Proteases/farmacologia , Tripsina , Papaína , Quimotripsina , Peptonas , Biomassa
4.
Braz J Med Biol Res ; 56: e12564, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37194834

RESUMO

The need to fully exploit fishing resources due to increasing production and consequent waste generation requires research to promote the sustainability of the fishing industry. Fish waste from the industry is responsible for relevant environmental contamination. However, these raw materials contain high amounts of collagen and other biomolecules, being attractive due to their industrial and biotechnological applicability. Thus, to reduce the waste from pirarucu (Arapaima gigas) processing, this study aimed to obtain collagen from pirarucu skin tissue. The extraction process used 0.05 M sodium hydroxide, 10% butyl alcohol, and 0.5 M acetic acid, with extraction temperature of 20°C. The obtained yield was 27.8%, and through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), it was determined that the collagen obtained was type I. This study showed that collagen solubility was highest at pH 3 and the lowest solubility was at concentrations of 3% sodium chloride. The denaturation temperature of collagen was 38.1°C, and its intact molecular structure was observed using the Fourier transform infrared spectrophotometry technique with an absorption radius of 1. The results showed that it was possible to obtain collagen from pirarucu skin at 20°C, which has the typical characteristics of commercial type I collagen. In conclusion, the procedures used may be considered to be an interesting alternative for collagen extraction, a new product obtained from the processing of fish waste.


Assuntos
Colágeno , Proteínas de Peixes , Animais , Proteínas de Peixes/análise , Proteínas de Peixes/química , Colágeno Tipo I , Pele/química , Peixes , Água Doce
5.
Braz. j. biol ; 83: e250003, 2023. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1339392

RESUMO

Abstract This study estimated the length-weight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m taken for standard length (SL - 0.1 cm precision) and total weight (TW - 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.


Resumo Este estudo estimou as relações comprimento-peso de 16 espécies de peixes que ocorrem às margens de praias arenosas ao longo da bacia do baixo Rio Negro, Amazônia brasileira. As espécies foram capturadas durante um dia de cada mês, de outubro a novembro de 2016, no início da manhã e no início da noite, usando rede de cerco (20 m de comprimento e 3,5 m de altura, 5 malha mm entre nós opostos). As medidas foram feitas para comprimento padrão (SL - precisão de 0,1 cm) e peso total (TW - precisão de 0,01 g). Os parâmetros a e b da equação WT = a.LTb foram estimados. Os valores de a variaram de 0,0018 a 0,0226 e os valores de b variaram de 2,5271 a 3,3244. Este estudo também fornece novos dados sobre comprimentos máximos para seis espécies, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa e Trachydoras microstomus, e novos reportes dos parâmetros da LWRs de 15 espécies de peixes.


Assuntos
Animais , Perciformes , Caraciformes , Characidae , Brasil , Rios
6.
Braz. j. med. biol. res ; 56: e12564, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1439703

RESUMO

The need to fully exploit fishing resources due to increasing production and consequent waste generation requires research to promote the sustainability of the fishing industry. Fish waste from the industry is responsible for relevant environmental contamination. However, these raw materials contain high amounts of collagen and other biomolecules, being attractive due to their industrial and biotechnological applicability. Thus, to reduce the waste from pirarucu (Arapaima gigas) processing, this study aimed to obtain collagen from pirarucu skin tissue. The extraction process used 0.05 M sodium hydroxide, 10% butyl alcohol, and 0.5 M acetic acid, with extraction temperature of 20°C. The obtained yield was 27.8%, and through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), it was determined that the collagen obtained was type I. This study showed that collagen solubility was highest at pH 3 and the lowest solubility was at concentrations of 3% sodium chloride. The denaturation temperature of collagen was 38.1°C, and its intact molecular structure was observed using the Fourier transform infrared spectrophotometry technique with an absorption radius of 1. The results showed that it was possible to obtain collagen from pirarucu skin at 20°C, which has the typical characteristics of commercial type I collagen. In conclusion, the procedures used may be considered to be an interesting alternative for collagen extraction, a new product obtained from the processing of fish waste.

7.
Braz. j. biol ; 83: 1-5, 2023. map, tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1468965

RESUMO

This study estimated the length–weight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m length and 3.5 m height, 5 mm mesh between opposite knots). Measurements were taken for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.


Este estudo estimou as relações comprimento-peso de 16 espécies de peixes que ocorrem às margens de praias arenosas ao longo da bacia do baixo Rio Negro, Amazônia brasileira. As espécies foram capturadas durante um dia de cada mês, de outubro a novembro de 2016, no início da manhã e no início da noite, usando rede de cerco (20 m de comprimento e 3,5 m de altura, 5 malha mm entre nós opostos). As medidas foram feitas para comprimento padrão (SL - precisão de 0,1 cm) e peso total (TW - precisão de 0,01 g). Os parâmetros a e b da equação WT = a.LTb foram estimados. Os valores de a variaram de 0,0018 a 0,0226 e os valores de b variaram de 2,5271 a 3,3244. Este estudo também fornece novos dados sobre comprimentos máximos para seis espécies, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa e Trachydoras microstomus, e novos reportes dos parâmetros da LWRs de 15 espécies de peixes.


Assuntos
Animais , Peixes/anatomia & histologia , Peixes/crescimento & desenvolvimento
8.
Braz. j. biol ; 832023.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1469181

RESUMO

Abstract This study estimated the lengthweight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m taken for standard length (SL 0.1 cm precision) and total weight (TW 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.


Resumo Este estudo estimou as relações comprimento-peso de 16 espécies de peixes que ocorrem às margens de praias arenosas ao longo da bacia do baixo Rio Negro, Amazônia brasileira. As espécies foram capturadas durante um dia de cada mês, de outubro a novembro de 2016, no início da manhã e no início da noite, usando rede de cerco (20 m de comprimento e 3,5 m de altura, 5 malha mm entre nós opostos). As medidas foram feitas para comprimento padrão (SL - precisão de 0,1 cm) e peso total (TW - precisão de 0,01 g). Os parâmetros a e b da equação WT = a.LTb foram estimados. Os valores de a variaram de 0,0018 a 0,0226 e os valores de b variaram de 2,5271 a 3,3244. Este estudo também fornece novos dados sobre comprimentos máximos para seis espécies, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa e Trachydoras microstomus, e novos reportes dos parâmetros da LWRs de 15 espécies de peixes.

9.
RSC Adv ; 12(40): 26418-26427, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-36275110

RESUMO

Exploring Heusler based materials for different practical applications has drawn more and more attention. In this work, the structural, electronic, magnetic, and mechanical properties of NaTMGe (TM = all 3d transition metals) half-Heusler compounds have been systematically investigated using first-principles calculations. The TM modification plays a determinant role in the fundamental properties. Except NaNiGe and NaCuGe, the studied materials exhibit good dynamical stability. Calculations reveal the non-magnetic semiconductor of NaScGe with a direct energy gap of 1.21 eV. Prospective spintronic applications of NaVGe and NaCrGe-NaMnGe are also suggested by their magnetic semiconductor and half-metallic behavior, respectively, where their magnetic properties follow the Slater-Pauling rule. Nevertheless, the remaining materials are either magnetic or non-magnetic metallic. For the magnetic systems, the magnetism is induced mainly by the TM constituents with either spin-up (V, Cr, Mn, and Fe) or spin-down (Co) 3d states. Calculated elastic constants indicate that all compounds are mechanically stable. Furthermore, they exhibit significant elastic anisotropy, where NaScGe and NaZnGe are the least and most anisotropic materials, respectively. Also, modifying the TM elements influences the materials' ductile and brittle behaviors. Our work unravels clearly the effects of TM modification on the fundamental properties of NaTMGe compounds. NaTMGe materials show excellent versatility with promising properties for optoelectronic and spintronic applications.

10.
J Chem Phys ; 156(23): 234106, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35732515

RESUMO

Dispersion interactions are one of the components of van der Waals (vdW) forces that play a key role in the understanding of intermolecular interactions in many physical, chemical, and biological processes. The theory of dispersion forces was developed by London in the early years of quantum mechanics. However, it was only in the 1960s that it was recognized that for molecules lacking an inversion center, such as chiral and helical molecules, there are chirality-sensitive corrections to the dispersion forces proportional to the rotatory power known from the theory of circular dichroism and with the same distance scaling law R-6 as the London energy. The discovery of the chirality-induced spin selectivity effect in recent years has led to an additional twist in the study of chiral molecular systems, showing a close relation between spin and molecular geometry. Motivated by it, we propose in this investigation to describe the mutual induction of charge and spin-density fluctuations in a pair A-B of chiral molecules by a simple physical model. The model assumes that the same fluctuating electric fields responsible for vdW forces can induce a magnetic response via a Rashba-like term so that a spin-orbit field acting on molecule B is generated by the electric field arising from charge density fluctuations in molecule A (and vice versa). Within a second-order perturbative approach, these contributions manifest as an effective intermolecular exchange interaction. Although expected to be weaker than the standard London forces, these interactions display the same R-6 distance scaling.


Assuntos
Teoria Quântica , Londres , Estereoisomerismo
11.
Phys Chem Chem Phys ; 24(4): 2209-2218, 2022 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-35013741

RESUMO

Exploration of new half-metallic materials for spintronic applications has drawn great attention from researchers. In this work, we investigate the structural, electronic, and magnetic properties of the NaMgO3 perovskite in the bulk and (001) surface conformations. The results show the half-metallic nature of bulk NaMgO3 generated by insulator spin-up channels with a large band gap of 6.08 eV and metallic spin-down channels. A total magnetic moment of 3 (µB) is obtained, which is produced mainly by O atoms with a local magnetic moment of 0.94 (µB). Once the bulk is cleaved along the (001) direction, atomic relaxation takes place to reach an equilibrium, where all constituent atoms exhibit an inward movement. Interestingly, the half-metallicity is retained from the bulk to the (001) surface conformation. The effects of slab termination and thickness on the surface energy, stability, band edges, spin-up energy gaps, and magnetic anisotropy will be also analyzed in detail. The results presented herein introduce the NaMgO3 perovskite as a promising half-metallic material to generate spin current in spintronic devices.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120434, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34624817

RESUMO

The luminescent properties of tryptophan in solvents less polar than water, such as acetone, and non-polar ones, such as cyclohexane, are experimentally studied and compared with theoretical calculations using time-dependent density functional theory (TD-DFT) methods. Since tryptophan may present different configurations and charge distributions, the most stable conformer is analyzed for both solvents, including its neutral and zwitterionic forms. To perform the simulation two clusters are proposed with the Zpt conformer in acetone: [Formula: see text] and [Formula: see text] , and four clusters with the Nag+ conformer in cyclohexane: (Trp)1-(C6H12), (Trp)2-(C6H12), (Trp)3-(C6H12) and (Trp)4-(C6H12), in order to conveniently emulate the concentration in each solvent by reducing the distance between adjacent tryptophan molecules as the concentration increases, since there is no control over the volume parameter. In each case, the UV-vis absorption is computed and compared with the experimental excitation spectra; the results show a good agreement. This calculation allows a more detailed analysis of the experimental results based on the properties of the molecular orbitals involved in electronic transitions. In the present work, a strong effect of the solvent acetone on tryptophan is observed; for this solvent, a charge transfer from the solute to solvent happens. This behavior does not occur with water (polar solvent) or cyclohexane (non-polar solvent). Finally, experimental spectroscopic data of Trp in cyclohexane are explained through the hydrogen bonds between amino acid molecules present in the fluorescent states. In this case, the theoretical and experimental results are compared and also show good agreement.


Assuntos
Acetona , Triptofano , Cicloexanos , Ligação de Hidrogênio , Solventes
13.
Braz J Biol ; 83: e250003, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34669803

RESUMO

This study estimated the length-weight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m taken for standard length (SL - 0.1 cm precision) and total weight (TW - 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.


Assuntos
Characidae , Caraciformes , Perciformes , Animais , Brasil , Rios
14.
J Phys Condens Matter ; 33(32)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34082415

RESUMO

In practice, modifying the fundamental properties of low-dimensional materials should be realized before incorporating them into nanoscale devices. In this paper, we systematically investigate the nitrogen (N) doping and oxygen vacancy (OV) effects on the electronic and magnetic properties of the beryllium oxide (BeO) monolayer using first-principles calculations. Pristine BeO single layer is a non-magnetic insulator with an indirectK-Γ gap of 5.300 eV. N doping induces a magnetic semiconductor nature, where the spin-up and spin-down band gaps depend on the dopant concentration and N-N separation. Creating one OV leads to the energy gap reduction of 31.06% with no spin-polarization, which is due to the abundant 2p electrons of the Be atoms nearest the OV site. The further increase to two OVs and varying the OV-OV distance affect the band gap values, however the spin independence is retained. The magnetic semiconducting behavior is also obtained by the simultaneous N doping and OV presence. Calculations reveal significant magnetization of the BeO@1N, BeO@2N-n, BeO@NOV-nsystems, which is produced mainly by the spin-up N-2p state. Except for the BeO@NOV-1 and BeO@NOV-2, whose magnetic properties are created by the spin-up 2p state of the Be atoms closest to the OV site. The variation of the N-N and N-OV distances keeps the ferromagnetic ordering in the BeO@2N and BeO@NOV layers. Results presented herein may propose efficient methods to artificially modify the physical properties of BeO monolayer, leading to the formation of novel two-dimensional (2D) materials for optoelectronic and spintronic applications.

15.
ACS Omega ; 6(23): 14824-14837, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34151064

RESUMO

Based on density functional theory (DFT) and the semiempirical method PM7, we analyze the encapsulation process of polluting gases and/or their adsorption on different sites, viz., on the inner wall, the outer wall, and on the boron nitride (BN) nanotube ends, with chirality (7,7) armchair. DFT calculations are performed using the Perdew-Burke-Ernzerhof (PBE) functional and the M06-2X method through the 6-31G(d) divided valence orbitals as an atomic basis. Various geometrical configurations were optimized by minimizing the total energy for all analyzed systems, including the calculation of vibrational frequencies, which were assumed to be of a nonmagnetic nature, and where the total charge was kept neutral. Results are interpreted in terms of adsorption energy and electronic force, as well as on the analysis of quantum molecular descriptors for all systems considered. The study of six molecules, namely, CCl4, CS2, CO2, CH4, C4H10, and C6H12, in gas phase is addressed. Our results show that C4H10, C6H12, and CCl4 are chemisorbed on the inner surfaces (encapsulation) and on the nanotube ends. In contrast, the other molecules CS2, CO2, and CH4 show weak interaction with the nanotube surface, leading thereby to physisorption. Our findings thus suggest that this kind of polluting gases can be transported within nanotubes by encapsulation.

16.
Neotrop Entomol ; 50(1): 100-113, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33398854

RESUMO

The susceptibility of 1st to 4th instars of Bemisia tabaci (Gennadius, 1989) (Hemiptera: Aleyrodidae) to three isolates of Cordyceps sp. (Hypocreales: Cordycipitaceae) was evaluated in screenhouse experiments under variable temperatures and moisture conditions. No differences in susceptibility to the Cordyceps sp. isolates were observed among 1st, 2nd, and 3rd instar nymphs with respect to median lethal time (LT50) values. Confirmed mortalities ranged from 63.7 to 87.8% when the isolates were tested at 5 × 107 conidia mL-1. The 4th instar was the least susceptible to the fungal isolates (≤ 36.6% mortality). However, 60.0 to 99.5% of the adults that emerged from 4th instar nymphs previously treated with the fungus succumbed to the infection. Temperature was more detrimental to Cordyceps sp. virulence towards B. tabaci nymphs than relative humidity (RH). At similar RH, median LT50 for 1st instar (9.4 days) was higher than for 3rd instar (5.3 days) when the fungus was tested at 5 × 107 conidia mL-1; minimal temperatures of ≥ 12.6°C compared to ≥ 17.0°C were registered for experiments with 1st and 3rd instars, respectively. However, temperatures ≥ 35°C for 4 to 6 h daily did not affect the efficacy of the fungus against nymphs. Cordyceps sp. showed high virulence to all life stages of B. tabaci at relatively low RH, and an ability to grow extensively over the leaf surface and to produce high amounts of conidia on infected hosts. These attributes certainly boost its potential as an important pest control component of B. tabaci biotype B, especially for management of populations resistant to synthetic insecticides.


Assuntos
Cordyceps/patogenicidade , Hemípteros/microbiologia , Ninfa/microbiologia , Animais , Brasil , Umidade , Controle Biológico de Vetores , Temperatura
17.
RSC Adv ; 11(56): 35614-35623, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-35493147

RESUMO

Since the successful synthesis of the MoSSe monolayer, two-dimensional (2D) Janus materials have attracted huge attention from researchers. In this work, the MoSO monolayer with tunable electronic and magnetic properties is comprehensively investigated using first-principles calculations based on density functional theory (DFT). The pristine MoSO single layer is an indirect gap semiconductor with energy gap of 1.02(1.64) eV as predicted by the PBE(HSE06) functional. This gap feature can be efficiently modified by applying external strain presenting a decrease in its value upon switching the strain from compressive to tensile. In addition, the effects of vacancies and doping at Mo, S, and O sites on the electronic structure and magnetic properties are examined. Results reveal that Mo vacancies, and Al and Ga doping yield magnetic semiconductor 2D materials, where both spin states are semiconductors with significant spin-polarization at the vicinity of the Fermi level. In contrast, single S and O vacancies induce a considerable gap reduction of 52.89% and 58.78%, respectively. Doping the MoSO single layer with F and Cl at both S and O sites will form half-metallic 2D materials, whose band structures are generated by a metallic spin-up state and direct gap semiconductor spin-down state. Consequently, MoV, MoAl, MoGa, SF, SCl, OF, and OCl are magnetic systems, and the magnetism is produced mainly by the Mo transition metal that exhibits either ferromagnetic or antiferromagnetic coupling. Our work may suggest the MoSO Janus monolayer as a prospective candidate for optoelectronic applications, as well as proposing an efficient approach to functionalize it to be employed in optoelectronic and spintronic devices.

18.
J Mol Graph Model ; 100: 107642, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32688130

RESUMO

It is known that high spin-polarization and magnetism can be found even in materials with neither transition metals nor rare earths. In this paper, we report results of the structural design, electronic structure, magnetic and optical properties of new equiatomic quaternary Heusler (EQH) KCaBX (X = S and Se) compounds. Electron exchangecorrelation interactions are described by the Wu-Cohen (WC) functional and Tran-Blaha modified Becke-Johnson exchange (mBJ) potential. Ferromagnetic ordering is stable for the cubic structure of space group F43 m in which the K, Ca, B and X atoms are located at 4c, 4d, 4a and 4b Wyckoff positions, respectively. Quaternaries at hand exhibit a perfect spin-polarization around the Fermi level, which is a result of the half-metallicity with metallic spin-up channel and semiconductor spin-dn channel. The ferromagnetic half-metallic and spin-flip band gaps are 2.648(2.470) and 0.673(0.526), respectively, for KCaBS(KCaBSe). Both studied compounds have a total magnetic moment of 2.000 µB. Additionally, the strain effect on the electronic and magnetic properties is also examined. Finally, the optical properties of the KCaBX alloys are investigated for energies up to 25 eV. Optical spectra show the metallic behavior at extremely low energies and semiconductor nature at higher energies. Interestingly, KCaBS and KCaBSe exhibit prospective absorption properties with a quite large absorption coefficient in the ultraviolet regime.


Assuntos
Eletrônica , Elementos de Transição , Ligas , Magnetismo , Estudos Prospectivos
19.
Arq. bras. med. vet. zootec. (Online) ; 72(1): 177-190, Jan.-Feb. 2020. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-1088927

RESUMO

Estudou-se o efeito do hipotireoidismo materno na expressão espaço-temporal de mediadores imunológicos e na população de células natural killers (NK) na decídua e na glândula metrial de ratas durante a gestação. Avaliou-se a detecção imunoistoquímica de interferon γ (IFNγ), do fator inibidor de migração (MIF), da interleucina 15 (IL15), do óxido nítrico sintase induzível (iNOS), a marcação com lectina DBA para evidenciação das células NK uterinas DBA+ e a expressão gênica de Ifnγ e Nos2. O hipotireoidismo aumentou o iNOS aos sete dias, a IL15 e o MIF aos 10 e 12 dias, o IFNγ e o MIF aos 14 DG e a expressão dos transcritos gênicos para iNos aos 12 e 19 dias e para Ifnγ aos 14 DG. O hipotireoidismo reduziu a imunomarcação de MIF e lectina DBA aos sete dias, lectina DBA aos 10 e 14 DG, IFNγ aos 12 dias, e a expressão de Ifnγ aos 10 e 19 DG e de iNOS aos 12, 14 e 19 DG, bem como reduziu seus transcritos gênicos aos 10 e 14 DG. Conclui-se que o hipotireoidismo compromete o perfil imunológico na interface materno-fetal ao longo da gestação, particularmente por reduzir o fator anti-inflamatório iNOS e a população de células uNK DBA+.(AU)


The goal of this study was to evaluate the effect of maternal hypothyroidism on the spatiotemporal expression of immunological mediators and population of Natural Killers cells in decidua and metrial gland of rats. Interferon gamma (IFNγ), migration inhibitory factor (MIF), interleukin 15 (IL15), inducible nitric oxide synthase (iNOS), and DBA-Lectin labeling for evidence of uNK DBA+ cells in decidua and genetic expression of Ifnγ and iNos by real-time RT-PCR were evaluated. Hypothyroidism increased protein expression of iNOS at 7 days, IL15 and MIF at 10 and 12 days, IFNγ and MIF at 14 DG in the decidua and/or metrial gland and the gene transcripts for iNOS at 12 and 19 days and for Inf at 14 DG. In addition, hypothyroidism reduced the protein expression of MIF and DBA-Lectin at 7 days, DBA-Lectin at 10 and 14 DG, IFNγ at 12 days, and the gene transcript to Ifnγ at 10 and 19 DGs. Hypothyroidism also reduced the protein expression of iNOS at 12, 14 and 19 DG and reduced its gene transcripts at 10 and 14 DGs. It is concluded that hypothyroidism compromises the immunology profile at the maternal-fetal interface throughout pregnancy, particularly by reducing the anti-inflammatory factor iNOS and population of uNK DBA+ cells.(AU)


Assuntos
Animais , Feminino , Gravidez , Ratos , Implantação do Embrião , Células Matadoras Naturais , Hipotireoidismo/veterinária , Glândula Metrial
20.
RSC Adv ; 10(43): 25609-25617, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-35518578

RESUMO

In this work, a new equiatomic quaternary Heusler (EQH) compound, MnVZrP, is predicted using first principles calculations. Simulations show the good stability of the material, suggesting experimental realization. Results show that MnVZrP is a magnetic semiconductor material, exhibiting semiconductor characteristics in both spin channels, however, with strong spin-polarization. Electronic band gaps of 0.97 and 0.47 eV are obtained in the spin-up and spin-dn states, respectively. Mainly the d-d coupling regulates the electronic band structure around the Fermi level. Strain effects on the electronic properties of the proposed compound are also investigated. Simulations give the total magnetic moment of 3 µ B satisfying the Slate-Pauling rule. The main magnetic contributions are given by the Mn and V constituents. The results presented here suggest the promising applicability of EQH MnVZrP as a spin-filter. Additionally, the elastic property calculations indicate the mechanical stability and elastic anisotropy. The work may be useful in the magnetic Heusler alloys field, introducing a new member to the small group of magnetic semiconductor EQH compounds for spin-filter applications.

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