Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Inorg Chem ; 63(28): 12910-12919, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38940638

RESUMO

Binary metal hydrides can act as low-temperature reducing agents for complex oxides in the solid state, facilitating the synthesis of anion-deficient oxide or oxyhydride phases. The reaction of LaSrCoRuO6, with CaH2 in a sealed tube yields the face-centered cubic phase LaSrCoRuO3.2H1.9. The reaction with LiH under similar conditions converts LaSrCoRuO6 to a mixture of tetragonal LaSrCoRuO4.8H1.2 and cubic LaSrCoRuO3.3H2.13. The formation of the LaSrCoRuOxHy oxyhydride phases proceeds directly from the parent oxide, with no evidence for anion-deficient LaSrCoRuO6-x intermediates, in contrast with many other topochemically synthesized transition-metal oxyhydrides. However, the reaction between LaSrCoRuO6 and LiH under flowing argon yields a mixture of LaSrCoRuO5 and the infinite layer phase LaSrCoRuO4. The change to all-oxide products when reactions are performed under flowing argon is attributed to the lower hydrogen partial pressure under these conditions. The implications for the reaction mechanism of these topochemical transformations is discussed along with the role of the hydrogen partial pressure in oxyhydride synthesis. Magnetization measurements indicate the LaSrCoRuOxHy phases exhibit local moments on Co and Ru centers, which are coupled antiferromagnetically. In contrast, LaSrCoRuO4 exhibits ferromagnetic behavior with a Curie temperature above 350 K, which can be rationalized on the basis of superexchange coupling between the Co1+ and Ru2+ centers.

2.
Angew Chem Int Ed Engl ; 63(6): e202313067, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38085493

RESUMO

Complex transition-metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition-metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6 , using Zr, yields LaSrCoRuO5 . This reduced phase contains an ordered array of apex-linked square-based pyramidal Ru3+ O5 , square-planar Co1+ O4 and octahedral Co3+ O6 units, consistent with the coordination-geometry driven disproportionation of Co2+ . Coordination-geometry driven disproportionation of d7 transition-metal cations (e.g. Rh2+ , Pd3+ , Pt3+ ) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition-metal such as cobalt leads to the expectation that d7+ Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+ O4 and Co3+ O6 units in LaSrCoRuO5 is surprising. Low-temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=1 /2 Ru3+ and S=1 Co1+ .

3.
Int J Biometeorol ; 67(10): 1607-1617, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37526762

RESUMO

Plants have always been able to adapt to climate change by reacting through various responses, mainly at the phenological level. The aim of this work is to investigate the behavior of specific tree species located in two phenological gardens in central Italy in relation to the temperature increases recorded in recent years. Specifically, four main phenological phases, BBCH_11, BBCH_19, BBCH_91, and BBCH_65, were monitored during a 14-year time period. The data of the weeks corresponding to the first appearance of each phenological phase and the respective heat accumulations for each species were cross-referenced with the meteorological data recorded by the stations in the two considered areas. Based on average temperature, calculated over reference periods, the species were divided by creating "warm" year groups and "cold" year groups so as to better highlight any differences in the behavior of the same species. In addition, a strong correlation was shown between the maximum temperatures in February and the advances of phenological phases BBCH_11 and BBCH_65. Most of the tree species have shown strong adaptation to climate warming, changing the period of occurrence of the phases themselves.


Assuntos
Jardins , Árvores , Temperatura , Estações do Ano , Itália , Mudança Climática
4.
Phys Rev Lett ; 129(24): 247201, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36563278

RESUMO

We study near-neighbor and dipolar Ising models on a lattice of corner-sharing octahedra. In an extended parameter range of both models, frustration between antiferromagnetism and a spin-ice-like three-in-three-out rule stabilizes a Coulomb phase with correlated dipolar and quadrupolar spin textures, both yielding distinctive neutron-scattering signatures. Strong further-neighbor perturbations cause the two components to order independently, resulting in unusual multi-k orders. We propose experimental realizations of our model in rare-earth antiperovskites.

5.
Phys Rev Lett ; 129(21): 217601, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36461960

RESUMO

According to previous theoretical work, the binary oxide CuO can become a room-temperature multiferroic via tuning of the superexchange interactions by application of pressure. Thus far, however, there has been no experimental evidence for the predicted room-temperature multiferroicity. Here, we show by neutron diffraction that the multiferroic phase in CuO reaches 295 K with the application of 18.5 GPa pressure. We also develop a spin Hamiltonian based on density functional theory and employing superexchange theory for the magnetic interactions, which can reproduce the experimental results. The present Letter provides a stimulus to develop room-temperature multiferroic materials by alternative methods based on existing low temperature compounds, such as epitaxial strain, for tunable multifunctional devices and memory applications.

6.
Environ Monit Assess ; 195(1): 118, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36396879

RESUMO

The objective of this work was to investigate the potential ecosystem services of 16 fruit trees to plan and manage more efficiently "Urban Forest," increasing also the resilience of cities to climate change. We evaluated the potential capacity of PM10 absorption, the storage of CO2 from the atmosphere, and the cooling of the environment through shading by the crown and through evapotranspiration. We observed that some species, such as Morus nigra, Juglans regia, Pyrus communis, and Cydonia oblonga, are able to store a higher quantity of CO2 than others over a period of 50 years, respectively, of 2.40 tons, 2.33 tons, 1.51 tons, and 0.96 tons. Ficus carica, Juglans regia, and Morus nigra were relevant for PM10 absorption, since they were able to absorb, referring to the year 2019, 146.4 gr/tree, 195.6 gr/tree, and 143.1 gr/tree, respectively. Results showed that these ecosystem functions depend principally on the morphological characteristics of the individuals: their height, DBH, expansion of their crowns, and characteristics of the foliage system.


Assuntos
Ecossistema , Frutas , Dióxido de Carbono , Monitoramento Ambiental , Árvores
7.
J Am Chem Soc ; 143(8): 3205-3218, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33596070

RESUMO

Understanding structural responses of metal-organic frameworks (MOFs) to external stimuli such as the inclusion of guest molecules and temperature/pressure has gained increasing attention in many applications, for example, manipulation and manifesto smart materials for gas storage, energy storage, controlled drug delivery, tunable mechanical properties, and molecular sensing, to name but a few. Herein, neutron and synchrotron diffractions along with Rietveld refinement and density functional theory calculations have been used to elucidate the responsive adsorption behaviors of defect-rich Zr-based MOFs upon the progressive incorporation of ammonia (NH3) and variable temperature. UiO-67 and UiO-bpydc containing biphenyl dicarboxylate and bipyridine dicarboxylate linkers, respectively, were selected, and the results establish the paramount influence of the functional linkers on their NH3 affinity, which leads to stimulus-tailoring properties such as gate-controlled porosity by dynamic linker flipping, disorder, and structural rigidity. Despite their structural similarities, we show for the first time the dramatic alteration of NH3 adsorption profiles when the phenyl groups are replaced by the bipyridine in the organic linker. These molecular controls stem from controlling the degree of H-bonding networks/distortions between the bipyridine scaffold and the adsorbed NH3 without significant change in pore volume and unit cell parameters. Temperature-dependent neutron diffraction also reveals the NH3-induced rotational motions of the organic linkers. We also demonstrate that the degree of structural flexibility of the functional linkers can critically be affected by the type and quantity of the small guest molecules. This strikes a delicate control in material properties at the molecular level.

8.
Inorg Chem ; 60(20): 15124-15127, 2021 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-34606249

RESUMO

The magnetic structure of NaYMnWO6 was determined by neutron powder diffraction measurements. Below 9 K, the magnetic structure is a helix to wave vector k = (0, 0.447, 1/2), in contrast with NaYNiWO6, which shows a transverse spin density wave with k = (0.47, 0, 0.49). By analyzing the differences in the spin exchanges of NaYMnWO6 and NaYNiWO6, and in the magnetic anisotropies of the Mn2+ (d5, S = 5/2) and the Ni2+ (d2, S = 1) ions, we show what factors govern the propagation direction of a noncollinear magnetic structure and whether it becomes a helix or a cycloid.

9.
Inorg Chem ; 60(4): 2195-2202, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33492967

RESUMO

We have investigated magneto-structural phase transitions in polycrystalline YVO3 using high-resolution neutron powder diffraction toward understanding the phenomenon of magnetization reversal. Contrary to earlier reports, our study reveals that both C-type and G-type antiferromagnetic ordering, corresponding to G-type and C-type orbital ordered phases, respectively, occur at the same temperature (TN = 115 K) with the G-type antiferromagnetic phase growing at the expense of the C-type one on cooling. These processes cease at TS ∼ 77 K; however, a minor (∼4%) untransformed C-type phase remains unchanged down to 1.7 K. The symmetry analysis indicates different symmetry origins of the Dzyaloshinskii-Moriya interaction in each phase, which can explain the magnetization reversal observed between TN and TS. We discuss that magnetic phase separation and associated weak ferromagnetism may be the common mechanism underlying the magnetization reversal phenomenon observed in other RVO3 systems (R = rare earth).

10.
Neurol Sci ; 42(9): 3865-3870, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33527209

RESUMO

BACKGROUND AND PURPOSE: Ketogenic diet (KD) is based on restriction of carbohydrate intake. Metabolism is forced to obtain energy starting from ß-oxidation of fatty acids which, turned into ketone bodies, can also be used by central nervous system (CNS). KD use in treatment of chronic migraine has recently been considered. We set out to verify modification of symptoms in patients with refractory chronic migraine in response to KD. METHODS: Fifty patients were enrolled of which 38 completed the procedures the study and 23 were considered in the statistics. All of the patients considered in our study were affected by medication overuse headache (MOH). They were on a KD for 3 months. The following parameters have been checked at t = 0 and every 30 days for 6 months: migraine episode length (n. hours/day), frequency (n. days/month), level of pain of every episode measured on a scale from 1 to 3 (1 = mild; 2 = moderate; 3 = severe), and n. analgesic drugs taken/month. RESULTS: Days with symptoms decreased from 30 (median value) to 7.5 with p < 0.0001. The duration of the migraine episodes decreased from 24 h (median value) to 5.5 h with p < 0.0016. The patients' pain level, initially at maximum value for 83% of the participants, improved for 55% of them (p < 0.0024). The number of drugs taken in a month decreased from 30 doses (median value) to 6 doses. CONCLUSIONS: It can be stated that a 3-month KD resulted in a reduction of painful symptoms of drug refractory chronic migraine. This result may suggest an improvement in quality of life of the patients, even without a tabulated data collection.


Assuntos
Dieta Cetogênica , Transtornos da Cefaleia Secundários , Transtornos de Enxaqueca , Analgésicos , Humanos , Transtornos de Enxaqueca/tratamento farmacológico , Qualidade de Vida , Resultado do Tratamento
11.
Inorg Chem ; 59(24): 17856-17859, 2020 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-33285061

RESUMO

The incommensurate magnetic structure (0.47, 0, 0.49) of NaYNiWO6 exhibits unconventional spin-density waves (SDWs) along the [100] direction, in which up and down spins alternate in each half-wave. This is in contrast to conventional SDWs, in which only one type of spin is present in each half-wave. We probed the formation of these unconventional SDWs by evaluating the spin exchanges of NaYNiWO6 based on density functional theory calculations and analyzing the nature of the spin frustration in NaYNiWO6 and by noting that a SDW is a superposition of two cycloids of opposite chirality. The unconventional SDWs along the [100] direction originate from the spin-frustrated antiferromagnetic chains of Ni2+ ions along that direction, leading to conventional SDWs along the [101] direction and unconventional SDWs along the [001] direction.

12.
Inorg Chem ; 59(9): 6613-6622, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32286805

RESUMO

The double perovskite Ba2CoOsO6, synthesized using solid-state methods at ambient pressure, is shown as a rare example of an oxide adopting the 6L-trigonal (S.G.: P3̅m1) perovskite structure. The structure, refined using a combination of X-ray and neutron diffraction data, showed the Co and Os were ordered over the two dimer sites with additional ordering over the corner-sharing sites. Bond valence calculations show the presence of the Co(II) and Os(VI) valence states, and the latter was confirmed using X-ray absorption spectroscopy. Bulk magnetic susceptibility measurements show Ba2CoOsO6 to undergo antiferromagnetic ordering near 100 K, and neutron diffraction showed an ordered moment on the Co3, Co4, and Os2 sites; whereas the Os1/Co1 remained disordered.

13.
Inorg Chem ; 59(21): 15898-15912, 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33058683

RESUMO

Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1_Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1_Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) µB (for Sr2CrO2Cr2As2) and 3.30(1) µB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) µB for Sr2CrO2Cr2As2 and 2.298(8) µB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers.

14.
Environ Monit Assess ; 192(11): 737, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-33128082

RESUMO

In order to estimate the impact of climate change on the phenological parameters and to compare them with the historical record, a decision support system (DSS) has been applied employing a Phenological Modelling Platform. Biological observations of two willow species (Salix acutifolia and smithiana Willd) in 3 gardens at different altitudes located in Central Italy were utilized to identify suitable phenological models related to four main vegetative phase timings (BBCH11, BBCH91, BBCH 94, BBCH95), and male full flowering (BBCH 65) clearly identifiable in these species. The present investigation identifies the best phenological models for the main phenophases allowing their practical application as real-time monitoring and plant development prediction tools. Sigmoid model revealed high performances in simulating spring vegetative phases, BBCH11 (First leaves unfolded), and BBCH91 (Shoot and foliage growth completed). Salix acutifolia Willd. development appeared to be more related to temperature amount interpreted by phenological models in comparison to Salix smithiana Willd. above all during spring (BBCH11 and 91), probably due to a different grade of phenotypic plasticity between the 2 considered species.


Assuntos
Salix , Altitude , Mudança Climática , Monitoramento Ambiental , Itália , Estações do Ano , Temperatura
15.
Phys Chem Chem Phys ; 21(14): 7261-7264, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30892327

RESUMO

The quantum magnet KOsO4 has been characterized by a combination of X-ray and neutron diffraction techniques. The tetrahedrally coordinated Os7+ 5d1S = 1/2 cations were determined to order antiferromagnetically along the c axis below 35 K. A miniscule ordered magnetic moment of 0.46(18) µB was determined per Os7+ cation.

16.
Sensors (Basel) ; 19(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443346

RESUMO

Artefact conditions need to be continuously monitored to avoid degradation effects naturally caused by time and public exploitation in order to increase the value of cultural assets. In this way, the atmospheric analysis of both biological and chemical pollutants potentially present inside conservation environments represents valid support for the adoption of preventive conservation actions by evaluating periodically the presence of risk for the same artefacts. The aim of the present study was to analyze the fungal particles, potentially biodeteriogen, through aerobiological volumetric monitoring, particularly inside valuable historical, artistic, and cultural sites. Different exposition and conservation typologies of the artefacts with different flows of visitors were considered. The applied methodologies have furnished a reliable description of biological air pollution due to the presence of fungal spores-moreover, they have allowed for the prevention of risk situations and the measurement of their evolution in order to limit degradation processes. Through aerobiological monitoring, it was possible to provide important indications for interventions of prevention, conservation and restoration of cultural heritage in indoor environments.


Assuntos
Poluentes Atmosféricos/isolamento & purificação , Monitoramento Ambiental/métodos , Esporos Fúngicos/crescimento & desenvolvimento , Poluição do Ar/prevenção & controle , Fungos/crescimento & desenvolvimento , Humanos
17.
Inorg Chem ; 57(16): 10312-10322, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30062877

RESUMO

Sr2Fe3Se2O3 is a localized-moment iron oxide selenide in which two unusual coordinations for Fe2+ ions form two sublattices in a 2:1 ratio. In the paramagnetic region at room temperature, the compound adopts the crystal structure first reported for Sr2Co3S2O3, crystallizing in space group Pbam with a = 7.8121 Å, b = 10.2375 Å, c = 3.9939 Å, and Z = 2. The sublattice occupied by two-thirds of the iron ions (Fe2 site) is formed by a network of distorted mer-[FeSe3O3] octahedra linked via shared Se2 edges and O vertices forming layers, which connect to other layers by shared Se vertices. As shown by magnetometry, neutron powder diffraction, and Mössbauer spectroscopy measurements, these moments undergo long-range magnetic ordering below TN1 = 118 K, initially adopting a magnetic structure with a propagation vector (1/2 - δ, 0, 1/2) (0 ≤ δ ≤ 0.1) which is incommensurate with the nuclear structure and described in the Pbam1 '( a01/2)000 s magnetic superspace group, until at 92 K ( TINC) there is a first order lock-in transition to a structure in which these Fe2 moments form a magnetic structure with a propagation vector (1/2, 0, 1/2) which may be modeled using a 2 a × b × 2 c expansion of the nuclear cell in space group 36.178 B a b21 m (BNS notation). Below TN2 = 52 K the remaining third of the Fe2+ moments (Fe1 site) which are in a compressed trans-[FeSe4O2] octahedral environment undergo long-range ordering, as is evident from the magnetometry, the Mössbauer spectra, and the appearance of new magnetic Bragg peaks in the neutron diffractograms. The ordering of the second set of moments on the Fe1 sites results in a slight reorientation of the majority moments on the Fe2 sites. The magnetic structure at 1.5 K is described by a 2 a × 2 b × 2 c expansion of the nuclear cell in space group 9.40 I a b (BNS notation).

18.
Angew Chem Int Ed Engl ; 57(49): 16099-16103, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30408302

RESUMO

Ordering of cations in different structural types occurs when there is a significant difference in the oxidation states and ionic radii of the ions involved. Herein we report an unusual ordering of isovalent cations Fe3+ and Al3+ in the polar rhombohedral R3 double perovskite structure of Bi2 FeAlO6 synthesized at high-pressure (6 GPa) and high-temperature (1000 °C). This ordered structure is derived from the 1:1 combination of the polar oxides BiFeO3 (R3c) and BiAlO3 (R3c), which results in reduction of symmetry to an R3 structure where the Fe3+ and Al3+ ions are ordered in a rock salt manner. However, these ions remain disordered in BiFe1-x Alx O3 (x=0.2, 0.3, 0.4) perovskites with R3c structure. The ordered compound undergoes antiferromagnetic ordering at TN ≈280 K. The butterfly nature of piezoelectric displacement loop further confirms the polar nature of the cation-ordered Bi2 FeAlO6 .

19.
Inorg Chem ; 55(9): 4381-90, 2016 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-27078522

RESUMO

The physical characterization and the extended crystallographic study of the double perovskite system Pb2Mn0.6Co0.4WO6 indicate an improper ferroelectric contribution to the polarization induced by the magnetic ordering. In the paramagnetic phase, the compound displays a centrosymmetric orthorhombic double perovskite structure with the Pmcn1' symmetry. The structure is strongly distorted by the lead stereoactivity. Magnetization measurements show two magnetic transitions at 188 and 9 K, but the time-of-flight neutron diffraction data provide evidence for a long-range magnetic ordering only below the second transition. Quantitative structure refinements combined with a comprehensive symmetry analysis indicate the Pm'c21' magnetic space group to be the adequate symmetry to describe the structural distortions and spin ordering in the ground state of the system. The symmetry implies a coexistence of a spontaneous ferromagnetic moment and a ferroelectric polarization along the orthogonal b- and c-axes, respectively, in the long-range ordered structure. Macroscopic measurements confirm the presence of the spontaneous polarization also below the first transition at 188 K, where only short-range magnetic correlations are evidenced by diffuse scattering in neutron diffraction.

20.
Environ Monit Assess ; 188(12): 687, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27882507

RESUMO

The physiological stress caused by particular pollution conditions can result in phenological phase shifts that can include a block in vegetative or reproductive development. The main aim of the present study was to determine and analyse the mean development trends of some winter deciduous species in comparison to the climate tendencies, as calculated within two phenological gardens in the Arezzo and Perugia areas of central Italy. Moreover, a phenological comparison between the guide species of the two phenological gardens, one located in an industrial area, and the other in a farming area, was carried out. The phenological evidences showed significant phase displacements for the common guide species present in both the gardens which however may be explained by the meteorological performances above all in the Perugia not polluted area. In these terms, there were no evident phenological effects on the plants from the industrial area pollutants in the Arezzo garden. Moreover, also the temperature reduction tendencies at the end of spring not influenced significantly the phenological behaviours of the plant species not inducing them toward a predictable delay of reproductive and adult leaves phases.


Assuntos
Poluição do Ar/efeitos adversos , Mudança Climática , Magnoliopsida/crescimento & desenvolvimento , Árvores/crescimento & desenvolvimento , Monitoramento Ambiental , Itália , Magnoliopsida/efeitos dos fármacos , Estações do Ano , Árvores/efeitos dos fármacos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA