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1.
Xenobiotica ; : 1-9, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38626291

RESUMO

In vitro systems are useful tools for unravelling species differences in xenobiotic metabolism.The current work aimed to validate the technique of precision-cut liver slices (PCLS) for comparative studies on xenobiotic metabolism in swine and cattle.PCLS from swine (n = 3) and cattle (n = 3) were produced using a Brendel-VitronTM Tissue Slicer and cultured for 6 h. Tissue viability was preserved throughout the whole culture period.Metabolic viability was evaluated using the anthelmintics albendazole (ABZ) and fenbendazole (FBZ) as model drugs, as well as other substrates of hepatic monooxygenases: benzydamine (BZ) N-oxygenase (FMO-dependent), and the O-dealkylations of 7-ethoxyresorufin (EROD, CYP1A1-dependent) and 7-methoxyresorufin (MROD, CYP1A2-dependent).ABZ S-oxygenation resulted 6-fold (cattle) and 13.6-fold (swine) higher (p = 0.001) compared to FBZ S-oxygenation.Similar BZ N-oxygenation and EROD activities were observed in PCLS cultures from both species. MROD was 2.5-fold higher (p = 0.033) in swine than in cattle. Similarly, ABZ S-oxygenation was 1.7-fold higher (p = 0.0002) in swine than in cattle. Conversely, a 82% higher (p = 0.0003) rate of FBZ S-oxygenation was evidenced in PCLS cultures from cattle compared to those from swine.Overall, this work shows that PCLS cultures are useful to obtain relevant information on species differences in xenobiotic metabolism.

2.
J Am Chem Soc ; 146(1): 954-960, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38156951

RESUMO

Harnessing sunlight via photosensitizing molecules is key for novel optical applications and solar-to-chemical energy conversion. Exploiting abundant metals such as iron is attractive but becomes challenging due to typically fast nonradiative relaxation processes. In this work, we report on the luminescence and excited-state reactivity of the heteroleptic [FeIII(pzTp)(CN)3]- complex (pzTp = tetrakis(pyrazolyl)borate), which incorporates a σ-donating trispyrazolyl chelate ligand and three monodentate σ-donating and π-accepting cyanide ligands. Contrary to the nonemissive [Fe(CN)6]3-, a broad emission band centered at 600 nm at room temperature has been recorded for the heteroleptic analogue attributed to the radiative deactivation from a 2LMCT excited state with a luminescence quantum yield of 0.02% and a lifetime of 80 ps in chloroform at room temperature. Bimolecular reactivity of the 2LMCT excited state was successfully applied to different alcohol photo-oxidation, identifying a cyanide-H bonding as a key reaction intermediate. Finally, this research demonstrated the exciting potential of [Fe(pzTp)(CN)3]- as a photo-oxidant, paving the way for further exploration and development of emissive Fe-based photosensitizers competent for photochemical transformations.

3.
Reprod Domest Anim ; 58(1): 3-9, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36149369

RESUMO

Camelids have many unique reproductive features that considerably differ from those of other domestic species. Females are induced ovulators with subsequent development of a corpus luteum (CL) with a short lifespan. Plasma progesterone concentration starts to increase on day 4, peaks on day 8-9 and, in non-pregnant animals, basal concentration is reached around day 10-11 post-induction of ovulation. Luteolytic pulses of prostaglandin F2α (PGF2α ) are firstly detected on day 7 or 8 (approximately on day 5-6 after ovulation), with maximal luteolytic peaks observed between days 9 and 11 post-mating, in coincidence with a high endometrial expression of cyclooxygenase 2, a limiting enzyme in prostaglandins synthesis. Unlike other species, oxytocin seems not to be involved in the luteolytic process in these species. The CL is the main source of progesterone secretion, and its function is required to support pregnancy. Despite constant research efforts, aspects of reproduction and maternal recognition of pregnancy in camelids remain not fully understood. A transient decrease and subsequent recovery in plasma progesterone concentration are observed after day 9 post-mating in pregnant animals in association with a pulsatile release of PGF2α and a transitory decrease in CL vascularization. Thus, embryo recognition should occur between days 8 and 12 post-mating. In camels, conceptus tissues exhibit aromatizing activity with the capacity to synthesize large amounts of oestradiol. Similarly, llama blastocysts secrete oestradiol-17ß during the preimplantation stage, with a higher production during the elongation period. An increase in the endometrial expression of oestrogen receptor α is also observed on day 12 post-mating. All these evidences suggest that oestrogen could be the signal released by the embryo at the time of its recognition in camelids. Besides, nearly 98% of pregnancies are carried out in the left horn. A decrease in the endometrial expression of mucin 1 and 16 genes has been reported, suggesting that these changes are crucial for successful embryo implantation; however, no differences have been observed between horns. Thus, maternal recognition of pregnancy in camelids is a particularly complex process that must occur in a concise time to allow the rescue of the CL and embryo survival.


Assuntos
Camelídeos Americanos , Luteólise , Gravidez , Feminino , Animais , Progesterona , Corpo Lúteo , Estradiol , Endométrio/metabolismo , Dinoprosta/metabolismo
4.
Acta Histochem ; 124(8): 151973, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36424682

RESUMO

Maternal recognition of pregnancy in llamas would be related to a still-unknown signal secreted by the embryo to extend the corpus luteum lifespan. In order to study llamas reproductive physiology and early pregnancy aspects, research on embryos between 8 and 12 days post-mating is essential. However, there is a lack of information on llama embryo paraffin embedding, a procedure that exhibits difficulties, mostly for embryo manipulation. This work presents an accessible, easy and rapid protocol for embedding llama blastocysts. Uterine flushings from four superovulated llamas were performed to recover embryos 8 days post-mating. Each embryo was fixed in 1 ml of 10 % neutral buffered formalin for 24 h, at 4 °C, and transferred to 70 % ethanol. Later, they were submitted to a series of baths: 500 µl PBS with 5 % bovine foetal serum solution (PBS+BFS) for 1 min; zona pellucida permeabilization with 500 µl PBS with 0.2 % Triton X-100 for 20 min; 500 µl PBS+BFS for 1 min; dehydration on baths with ascendent grades of ethanol (70 %, 96 %, and 100 % twice) for 10 min each; and bath of butanol for 5 min. Finally, embryos were embedded in a pellet of paraffin and afterwards in a paraffin block. Complete sections from 8 of 13 grade I and II embryos were obtained. In conclusion, by applying this method, good quality sections with preserved embryo morphology suitable for histological, histochemical or immunohistochemical approaches would be possible to acquire.


Assuntos
Camelídeos Americanos , Feminino , Gravidez , Bovinos , Animais , Inclusão em Parafina , Parafina , Embrião de Mamíferos , Etanol
5.
Clin Lymphoma Myeloma Leuk ; 22(6): e405-e413, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35042679

RESUMO

INTRODUCTION/BACKGROUND: Multiple Myeloma (MM) is a plasma cell derived clonal disorder that represents around 1% of all newly diagnosed neoplasms. Limited data regarding MM treatment in Latin America is available, and access to novel agents for a substantial portion of the population is limited by their high costs. MATERIALS (OR PATIENTS) AND METHODS: RENEHOC is a bidirectional (retrospective and prospective) multicenter observational registry of hematological malignancies in Colombia. MM patients included up to July 2020 were analyzed on this report. RESULTS: 890 are reported with a median follow-up of 18 months (IQR: 7-42 months). Patients were classified by age group (≤ or > 65 years). Median age at diagnosis was 67 years (IQR: 59-75 years) and 47.1% of patients were women. 709 patients (79.6%) received Bortezomib-based schemes as part of the first line. Two hundred and fifty-two patients (28.3%) were consolidated with Autologous Stem Cell Transplantation (ASCT) in first-line. ASCT consolidation and age were the main independent factors influencing outcomes; in the non-ASCT cohort, 5-year overall survival was 48.7% (CI 41.8-55.2) compared to 80.7% (CI 73-86.4) in ASCT patients. CONCLUSION: This data depicts the reality of MM in Colombia, which likely reflects other Latin American countries, where access barriers to diagnosis and treatment are echoed in advanced stage diagnosis and a low rate of transplants. These seem to negatively impact survival despite the availability of most novel drugs approved for this disease. Thus, emphasizing the paradox that prevails in most of the region: availability without equitable access.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Mieloma Múltiplo , Idoso , Bortezomib/uso terapêutico , Colômbia/epidemiologia , Feminino , Humanos , Masculino , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/epidemiologia , Mieloma Múltiplo/terapia , Estudos Prospectivos , Sistema de Registros , Estudos Retrospectivos , Transplante Autólogo
6.
Dalton Trans ; 50(44): 16176-16184, 2021 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-34718361

RESUMO

Bare (1) and silica coated (1@SiO2) spin crossover (SCO) nanoparticles based on the polymer {[Fe(NH2Trz)3](BF4)2}n have been prepared following a water-in-oil synthetic procedure. For 1, the critical temperatures of the spin transition are TC↓ = 214.6 K and TC↑ = 220.9 K. For 1@SiO2, the abruptness of the transition is enhanced and the critical temperatures are centred at room temperature (TC↓ = 292.1 K and TC↑ = 296.3 K). An inert Re(I) complex of formula [Re(phen)(CO)3(PETES)](PF6) (phen = 1, 10-phenanthroline; PETES = 2(4-pyridylethyl)triethoxysilane) (Re) was also synthesized yielding intense green emission centred at λem = 560 nm. The grafting of this complex on the silica shell of 1@SiO2 led to a bifunctional SCO-luminescence composite (1@SiO2/Re) whose luminescence properties were tuned by the spin state switching. Temperature-variable photophysical studies showed that luminescence and spin transition were synchronized through a radiative (trivial) energy transfer mechanism between the Re(I) and the Fe(II)-LS (LS, Low Spin) centres.

7.
Dalton Trans ; 49(43): 15404-15416, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-33140796

RESUMO

The reaction of a bulky acetyl acetone ligand 1,3-dimesitylpropane-1,3-dione (MesacacH) with hydrated lanthanide chlorides in the presence of tetramethylammonium hydroxide afforded a new family of neutral mononuclear LnIII complexes [Ln(Mesacac)3(DMF)] (Ln = Dy (1); Tb (2); Y0.91Dy0.09 (3); and Er (4)). The molecular structures of these complexes were confirmed by single crystal X-ray diffraction studies. The coordination geometries of the LnIII centre were analysed by SHAPE analysis which revealed a capped octahedral geometry in 1-4. Photoluminescence studies showed ligand-sensitized green emissions for 2 with an appreciable quantum yield of 0.83%. Static (dc) and dynamic (ac) magnetic studies of complexes 1 and 3 were performed. The dynamic magnetic study revealed that complex 1 exhibits zero-field slow relaxation of the magnetization without showing a clear maximum in the out-of-phase ac susceptibility plots. However, magnetic dilution of 1 with the YIII metal ion (complex 3) and/or the application of a dc magnetic field induces a strong frequency dependence of the ac susceptibility signals with χ''M peaks in the 3-10 K temperature range, thus supporting field-induced SMM behaviour of 1. The relaxation process takes place through a combination of the Orbach and Raman mechanisms. The fitting of the temperature dependence of the relaxation time to the equation τ-1 = τ0-1 exp(-Ueff/kBT) + BTn, allows the extraction of the effective energy barrier Ueff/kB = 70 K (48.7 cm-1) and pre-exponential parameter of τ0 = 2.7 × 10-7 s for the Orbach mechanism (first term) and the parameters B = 0.04 s-1 K-n and n = 6.11, for the Raman mechanism (second term).

8.
Larenas-Linnemann, Désirée; Rodríguez-Pérez, Noel; Luna-Pech, Jorge A; Rodríguez-González, Mónica; Blandón-Vijil, María Virginia; Del-Río-Navarro, Blanca E; Costa-Domínguez, María Del Carmen; Navarrete-Rodríguez, Elsy Maureen; Macouzet-Sánchez, Carlos; Ortega-Martell, José Antonio; Pozo-Beltrán, César Fireth; Estrada-Cardona, Alan; Arias-Cruz, Alfredo; Rodríguez Galván, Karen Guadalupe; Brito-Díaz, Herson; Canseco-Raymundo, María Del Rosario; Castelán-Chávez, Enrique Emanuel; Escalante-Domínguez, Alberto José; Gálvez-Romero, José Luis; Gómez-Vera, Javier; González-Díaz, Sandra Nora; Guerrero-Núñez, María Gracia Belinda; Hernández-Colín, Dante Daniel; Macías-Weinmann, Alejandra; Mendoza-Hernández, David Alejandro; Meneses-Sánchez, Néstor Alejandro; Mogica-Martínez, María Dolores; Moncayo-Coello, Carol Vivian; Montiel-Herrera, Juan Manuel; O'Farril-Romanillos, Patricia María; Onuma-Takane, Ernesto; Ortega-Cisneros, Margarita; Rangel-Garza, Lorena; Stone-Aguilar, Héctor; Torres-Lozano, Carlos; Venegas-Montoya, Edna; Wakida-Kusunoki, Guillermo; Partida-Gaytán, Armando; López-García, Aída Inés; Macías-Robles, Ana Paola; Ambriz-Moreno, María de Jesús; Azamar-Jácome, Amyra Ali; Beltrán-De Paz, Claudia Yusdivia; Caballero-López, Chrystopherson; Fernández de Córdova-Aguirre, Juan Carlos; Fernández-Soto, José Roberto; Lozano-Sáenz, José Santos; Oyoqui-Flores, José Joel; Osorio-Escamilla, Roberto Efrain; Ramírez-Jiménez, Fernando.
World Allergy Organ J ; 13(8): 100444, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32884611

RESUMO

BACKGROUND: Allergen immunotherapy (AIT) has a longstanding history and still remains the only disease-changing treatment for allergic rhinitis and asthma. Over the years 2 different schools have developed their strategies: the United States (US) and the European. Allergen extracts available in these regions are adapted to local practice. In other parts of the world, extracts from both regions and local ones are commercialized, as in Mexico. Here, local experts developed a national AIT guideline (GUIMIT 2019) searching for compromises between both schools. METHODS: Using ADAPTE methodology for transculturizing guidelines and AGREE-II for evaluating guideline quality, GUIMIT selected 3 high-quality Main Reference Guidelines (MRGs): the European Academy of Allergy, Asthma and Immunology (EAACI) guideines, the S2k guideline of various German-speaking medical societies (2014), and the US Practice Parameters on Allergen Immunotherapy 2011. We formulated clinical questions and based responses on the fused evidence available in the MRGs, combined with local possibilities, patient's preference, and costs. We came across several issues on which the MRGs disagreed. These are presented here along with arguments of GUIMIT members to resolve them. GUIMIT (for a complete English version, Supplementary data) concluded the following. RESULTS: Related to the diagnosis of IgE-mediated respiratory allergy, apart from skin prick testing complementary tests (challenges, in vitro testing and molecular such as species-specific allergens) might be useful in selected cases to inform AIT composition. AIT is indicated in allergic rhinitis and suggested in allergic asthma (once controlled) and IgE-mediated atopic dermatitis. Concerning the correct subcutaneous AIT dose for compounding vials according to the US school: dosing tables and formula are given; up to 4 non-related allergens can be mixed, refraining from mixing high with low protease extracts. When using European extracts: the manufacturer's indications should be followed; in multi-allergic patients 2 simultaneous injections can be given (100% consensus); mixing is discouraged. In Mexico only allergoid tablets are available; based on doses used in all sublingual immunotherapy (SLIT) publications referenced in MRGs, GUIMIT suggests a probable effective dose related to subcutaneous immunotherapy (SCIT) might be: 50-200% of the monthly SCIT dose given daily, maximum mixing 4 allergens. Also, a table with practical suggestions on non-evidence-existing issues, developed with a simplified Delphi method, is added. Finally, dissemination and implementation of guidelines is briefly discussed, explaining how we used online tools for this in Mexico. CONCLUSIONS: Countries where European and American AIT extracts are available should adjust AIT according to which school is followed.

9.
Theriogenology ; 156: 2-10, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32652325

RESUMO

Mycobacterium cell wall fraction (MCWF) is a biological component made up of molecules with immunostimulant properties, which is therapeutically used to modulate persistent breeding-induced endometritis (PBIE). The aim of this study was to analyze the effect of this immunomodulator on the endometrial histological structure during the diestrus of PBIE-resistant and -susceptible mares that either received treatment with MCWF or not. The experiment was conducted with 10 resistant mares (RM) and 9 susceptible mares (SM). In the first estrous cycle of the trial, all mares were inseminated with dead semen as an inflammatory stimulus (Group A); at the next cycle, all mares were inseminated with dead semen and treated with a MCWF commercial immunomodulator (Group B). In both groups, endometrial biopsies were taken on day 7 post-ovulation (diestrus). Endometrial biopsies of untreated-RM (UTRM, n = 6), untreated-SM (UTSM, n = 7) MCWF-treated-RM (TRM, n = 6) and MCWF-treated-SM (TSM, n = 6) were evaluated. They were randomly chosen as representative mares of Group A and B, respectively. The height of lining and glandular epithelia, glandular diameter, glandular density and glandular area were evaluated. The histological structure revealed lymphocytic infiltration and dilated, tortuous glands with some glandular nests, particularly in UTSM. The histomorphometrical results showed no differences (ρ > 0.05) between the analyzed groups. This would indicate that post-service treatment with the MCWF immunomodulator does not modify the endometrial histoarchitecture but, apparently, its action would be mainly based on the stimulation of the cellular and humoral immune responses.


Assuntos
Endometrite , Doenças dos Cavalos , Mycobacterium , Animais , Parede Celular , Endometrite/veterinária , Endométrio , Feminino , Cavalos
10.
Br J Neurosurg ; 34(4): 362-369, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31353968

RESUMO

Background: Sympathetic chain interruption is the gold standard treatment for essential hyperhidrosis. Postoperative compensatory hyperhidrosis, the main reason for patients' dissatisfaction, is reduced by selectively lesioning white and grey rami communicantes (ramicotomy).Objective: To develop an endoscopic surgical technique that interrupts only T3 and T4 grey rami communicantes to minimize compensatory hyperhidrosis.Material and Methods: T3 and T4 grey rami communicantes ramicotomy in fifteen cold-preserved cadavers through a uniportal axillary endoscopic approach. The sympathetic chain, its ganglia, and white rami communicantes were left intact. On opening the chest, the sympathetic chain, rami communicantes and ganglia were dissected, photographed, measured and excised for histological examination.Results: Dissecting the grey rami communicantes is feasible as they consistently lie between the intercostal nerve and the homonymous sympathetic ganglion. At some levels, Kuntz nerves, as well as more than one grey ramus communicans, can be found. White rami communicantes are more medial, therefore damaging them can be avoided. Intercostal veins can be obstructive, but these can be controlled via coagulation or clipping if necessary.Conclusion: Uniportal endoscopic selective excision of the T3 and T4 grey rami communicantes is feasible without damaging the white rami communicantes, the sympathetic chain or its ganglia. Clipping the grey rami communicantes is technically possible but not reliable due to their thin diameter. This study confirms that T3 and T4 grey rami sympathetic block is technically feasible. Its application might reduce compensatory hyperhidrosis, but clinical studies are needed.


Assuntos
Hiperidrose , Simpatectomia , Cadáver , Estudos de Viabilidade , Gânglios Simpáticos/anatomia & histologia , Humanos , Hiperidrose/cirurgia , Resultado do Tratamento
12.
Front Chem ; 7: 229, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31032249
13.
Dalton Trans ; 48(15): 4857-4866, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30869724

RESUMO

The reaction of a tridentate NNO donor ligand, 4-nitro-2-((2-(pyridine-2-yl)hydrazono)methyl)phenol (HL) with lanthanide(iii) nitrates in the presence of triethylamine afforded a new family of neutral mononuclear LnIII complexes [Ln(NO3)(L)2(HOCH3)] (Ln = Gd; (1) Tb; (2), Dy; (3), and Ho (4). The mononuclear complexes were structurally characterized by single crystal X-ray diffraction studies which revealed a spherical tricapped trigonal prism geometry with a pseudo D3h symmetry around the LnIII centre. Static (dc) and dynamic (ac) magnetic studies have been performed on these complexes. Field-induced single-ion magnet behaviour was observed in the DyIII analogue with an effective energy barrier and an pre-exponential factor of Δ/kB = 68(2) K and τ0 = 1.8 × 10-7 s, respectively.

14.
Br J Neurosurg ; 33(1): 12-16, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30450999

RESUMO

PURPOSE: Effective treatment of medical conditions relies on proper diagnosis. Clinical trials show the safety and effectiveness of sacroiliac joint (SIJ) fusion in patients with chronic SI joint dysfunction. To what extent is the condition under recognised? OBJECTIVE: To determine whether under recognition of SIJ pain affects healthcare trajectories in Spanish patients with low back pain. METHODS: Retrospective study of characteristics and consequences of 189 patients with persistent SIJ pain seen in an outpatient neurosurgery clinic. RESULTS: Patients with SIJ pain who were denied surgical treatment had a longer pain duration, higher likelihood of prior lumbar fusion, and a high rate (63%) of lumbar fusion within 2 years prior to SIJ pain diagnosis, which, in most cases, provided little benefit. CONCLUSIONS: Lack of knowledge of the role of the SIJ in chronic low back pain probably results in diagnostic confusion and may lead to misdirected treatment.


Assuntos
Artralgia/cirurgia , Dor Lombar/cirurgia , Articulação Sacroilíaca/cirurgia , Fusão Vertebral/estatística & dados numéricos , Dor Crônica/cirurgia , Feminino , Humanos , Região Lombossacral/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
15.
Front Chem ; 6: 537, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30467538

RESUMO

Chiral bipyrimidine-bridged dinuclear LnIII complexes of general formula [(µ-bipym){((+)-tfacam)3Ln}2] and [(µ-bipym){((-)-tfacam)3Ln}2], have been prepared from the assembly of Ln(AcO)3·nH2O (LnIII = Dy, Gd), (+)/(-)-3-(trifluoroacetyl)camphor enantiopure ligands ((+)/(-)-Htfacam) and bipyrimidine (bipym). The structure and chirality of these complexes have been supported by single-crystal X-Ray diffraction and circular dichroism. The study of the magnetic properties of the GdIII complexes revealed a very weak antiferromagnetic interaction between the GdIII ions through the bipyrimidine bridging ligand. Ab initio CASSCF calculations indicated that the ground Kramers doublet (KD) of both DyIII centers is almost purely axial with the anisotropy axis located close to the two tfacam-ligands at opposite sides of each DyIIIatom, which create an axial crystal field. In keeping with this, ac dynamic measurements indicated slow relaxation of the magnetization at zero field with U eff = 55.1 K, a pre-exponential factor of τo = 2.17·10-6 s and τQTM = 8 µs. When an optimal dc field of 0.1 T is applied, QTM is quenched and U eff increases to 75.9 K with τo = 6.16 × 10-7 s. The DyN2O8 coordination spheres and SMM properties of [(µ-bipym){((+)-tfacam)3Ln}2] and their achiral [(Dy(ß-diketonate)3)2(µ-bpym)]analogous have been compared and a magneto-structural correlation has been established, which has been supported by theoretical calculations. In contrast to the GdIII compounds, the magnetic exchange interaction between the DyIII ions has been calculated to be very weak and, generally, ferromagnetic in nature. Relaxation mechanisms for [(µ-bipym){((+)-tfacam)3Ln}2] and previously reported analogous have been proposed from ab initio calculations. As the magnetic exchange interaction found to be very weak, the observed magnetization blockade in these systems are primarily dictated by the single ion anisotropy of DyIII ions.

16.
Front Chem ; 6: 420, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30258840

RESUMO

The coordination chemistry of dysprosium and terbium toward phosphine and arsine oxides was further explored. Thus, the new nitrate [M(NO3)3(Ph3PO)3] (M = Tb, 1; Dy, 2), [Dy(NO3)3(EtOH)(Ph3XO)2] (X = P, 3; As, 4), chloride [DyCl2(Ph3AsO)4]Cl (5), triflate [Dy(OTf)2(MePh2PO)4]OTf (6; OTf = triflate) and hexafluoroacetylacetonate [M(hfa)3(Ph3PO)2] (hfa = hexafluoroacetylacetonate; M = Tb, 7; Dy, 8) complexes were isolated and fully characterized. The crystal structures of 1·CH3CN, 2·CH3CN, 4, 5·2.75EtOH·1.25H2O, 6, 7, and 8 show MO9 cores in 1, 2, and 4, with highly distorted geometry, between spherical capped square antiprism and muffin-like, hexacoordinated environments for the dysprosium ions in 5 and 6, with octahedral geometry, and octa-coordination for the lanthanoid metals in 7 and 8, with geometry closer to square antiprism. Comparison of the magnetic behavior of all the complexes allows analyzing which metal ion (Tb or Dy), phosphine or arsine oxide, or anionic ligand favor more the slow relaxation of the magnetization. Alternating current magnetic measurements show that only 2, 4, and 8 present slow relaxation of the magnetization in the presence of an external magnetic field, 8 being the complex with the highest U eff (44.85 K) of those described herein.

17.
Inorg Chem ; 57(16): 10100-10110, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-30074783

RESUMO

Three dinuclear complexes, [Tb2(H2daps)2(CH3OH)5.5(H2O)0.5](Cl)2 (Tb2Cl), [Dy2(H2daps)2(Cl)(CH3OH)3(H2O)]Cl (Dy2Cl), and [Dy2(H2daps)2(H2O)6](CF3SO3)2 (Dy2CF3SO3), as well as the heterohexanuclear compound [Zn2Dy4(daps)2(Hdaps)(Cl)3(OH)2(CH3OH)(H2O)5] (Zn2Dy4) (H4daps: 2,6-bis(1-salicyloylhydrazonoethyl)pyridine), which crystallize with different lattice molecules, show their hexa- or heptadentate hydrazone ligands acting with hitherto unknown µ2-κ5:κ1, µ3-κ5:κ4:κ1, µ4-κ5:κ4:κ1:κ1, or µ4-κ5:κ2:κ1:κ1 bridging modes. The single X-ray crystal structures of the dinuclear complexes show nine-coordinated N3 O6 environments for lanthanoid atoms in Tb2Cl and Dy2CF3SO3, with distorted geometries, between spherical capped square antiprism and muffin-like, while the dysprosium atoms in Dy2Cl are eight-coordinated, with distorted triangular dodecahedron geometries. In the case of Zn2Dy4, both eight-coordinated, O8 and O7 Cl, as well as nine-coordinated N3 O6 environments coexist in the crystal structure, with biaugmented trigonal prism, triangular dodecahedron, and muffin-like pseudogeometries. The magnetic study of all the complexes shows that none of the pure samples behaves as a single molecular magnet (SMM) and that the quantum tunnel cannot be removed by dilution of any of the dinuclear complexes, but except in diluted [Y1.904Dy0.096(H2daps)2(Cl)(H2O)4]Cl (Dy2Cl@Y), behaves as a weak field induced SMM. The heterohexanuclear Zn2Dy4 complex also lacks slow relaxation of the magnetization.

18.
Inorg Chem ; 57(11): 6362-6375, 2018 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-29775043

RESUMO

Herein we report a dinuclear [(µ-mbpymNO){(tmh)3Dy}2] (1) single-molecule magnet (SMM) showing two nonequivalent DyIII centers, which was rationally prepared from the reaction of Dy(tmh)3 moieties (tmh = 2,2,6,6-tetramethyl-3,5-heptanedionate) and the asymmetric bis-bidentate bridging ligand 4-methylbipyrimidine (mbpymNO). Depending on whether the DyIII ions coordinate to the N^O or N^N bidentate donor sets, the DyIII sites present a NO7 ( D2 d geometry) or N2O6 ( D4 d) coordination sphere. As a consequence, two different thermally activated magnetic relaxation processes are observed with anisotropy barriers of 47.8 and 54.7 K. Ab initio calculations confirm the existence of two different relaxation phenomena and allow one to assign the 47.8 and 54.7 K energy barriers to the Dy(N2O6) and Dy(NO7) sites, respectively. Two mononuclear complexes, [Dy(tta)3(mbpymNO)] (2) and [Dy(tmh)3(phenNO)] (3), have also been prepared for comparative purposes. In both cases, the DyIII center shows a NO7 coordination sphere and SMM behavior is observed with Ueff values of 71.5 K (2) and 120.7 K (3). In all three cases, ab initio calculations indicate that relaxation of the magnetization takes place mainly via the first excited-state Kramers doublet through Orbach, Raman, and thermally assisted quantum-tunnelling mechanisms. Pulse magnetization measurements reveal that the dinuclear and mononuclear complexes exhibit hysteresis loops with double- and single-step structures, respectively, thus supporting their SMM behavior.

19.
Neurosurg Focus ; 44(VideoSuppl1): V1, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29291295

RESUMO

Axillary nerve injury is common after brachial plexus injuries, particularly with shoulder luxation. Nerve grafting is the traditional procedure for postganglionic injuries. Nerve transfer is emerging as a viable option particularly in late referrals. At the proximal arm the radial and axillary nerves lie close by. Sacrificing one of the triceps muscle nerve branches induces little negative consequences. Transferring the long head of the triceps nerve branch is a good option to recover axillary nerve function. The surgical technique is presented in a video, stressing the steps to achieve a successful result. The video can be found here: https://youtu.be/WbVbpMuPxIE .


Assuntos
Axila/lesões , Axila/cirurgia , Plexo Braquial/lesões , Plexo Braquial/cirurgia , Transferência de Nervo/métodos , Nervo Radial/transplante , Humanos , Masculino , Pessoa de Meia-Idade
20.
ACS Omega ; 3(5): 5202-5211, 2018 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458734

RESUMO

The reaction of 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl] phenol (LH3) with lanthanide metal salts followed by the addition of nickel acetate allowed isolation of a family of octanuclear complexes, [Ni4Ln4(µ2-OH)2(µ3-OH)4(µ-OOCCH3)8(LH2)4]·(OH)2·xH2O. Single crystal X-ray diffraction studies of these complexes reveal that their central metallic core consists of two tetranuclear [Ni2Ln2O4] cubane subunits fused together by acetate and hydroxide bridges. The magnetic study of these complexes reveals a ferromagnetic interaction between the LnIII and the NiII center. The magnitude of exchange coupling between the NiII and LnIII center, parametrized from the magnetic data of the Gd analogue, gives J = +0.86 cm-1. The magneto caloric effect, studied for the NiII 4GdIII 4 complex, shows a maximum of magnetic entropy change, -ΔS m = 22.58 J kg-1 K-1 at 3 K for an applied external field of 5 T.

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