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1.
Cancer ; 2020 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-32639615

RESUMO

Because of the national emergency triggered by the coronavirus disease 2019 (COVID-19) pandemic, government-mandated public health directives have drastically changed not only social norms but also the practice of oncologic medicine. Timely head and neck cancer (HNC) treatment must be prioritized, even during emergencies. Because severe acute respiratory syndrome coronavirus 2 predominantly resides in the sinonasal/oral/oropharyngeal tracts, nonessential mucosal procedures are restricted, and HNCs are being triaged toward nonsurgical treatments when cures are comparable. Consequently, radiation utilization will likely increase during this pandemic. Even in radiation oncology, standard in-person and endoscopic evaluations are being restrained to limit exposure risks and preserve personal protective equipment for other frontline workers. The authors have implemented telemedicine and multidisciplinary conferences to continue to offer standard-of-care HNC treatments during this uniquely challenging time. Because of the lack of feasibility data on telemedicine for HNC, they report their early experience at a high-volume cancer center at the domestic epicenter of the COVID-19 crisis.

2.
Phys Chem Chem Phys ; 22(25): 14293-14308, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32558853

RESUMO

The [AnIV(DPA)3]2- series with An = Th, U, Np, Pu has been synthesized and characterized using SC-XRD and vibrational spectroscopy. First principles calculations were performed, the total electron density is analyzed using the Quantum Theory of Atoms in Molecules. Crystal field parameters and strength parameters are deduced following a previous work on the LnIII analog series e.g. [J. Jung et al., Chem. - Eur. J., 2019, 25, 15112]. The trends in the parameters along the series are compared to the LnIII complexes. They evidence larger covalent interactions and larger J mixing.

3.
Cancer ; 126(9): 1905-1916, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32097507

RESUMO

BACKGROUND: Proton therapy (PT) improves outcomes in patients with nasal cavity (NC) and paranasal sinus (PNS) cancers. Herein, the authors have reported to their knowledge the largest series to date using intensity-modulated proton therapy (IMPT) in the treatment of these patients. METHODS: Between 2013 and 2018, a total of 86 consecutive patients (68 of whom were radiation-naive and 18 of whom were reirradiated) received PT to median doses of 70 grays and 67 grays relative biological effectiveness, respectively. Approximately 53% received IMPT. RESULTS: The median follow-up was 23.4 months (range, 1.7-69.3 months) for all patients and 28.1 months (range, 2.3-69.3 months) for surviving patients. The 2-year local control (LC), distant control, disease-free survival, and overall survival rates were 83%, 84%, 74%, and 81%, respectively, for radiation-naive patients and 77%, 80%, 54%, and 66%, respectively for reirradiated patients. Among radiation-naive patients, when compared with 3-dimensional conformal proton technique, IMPT significantly improved LC (91% vs 72%; P < .01) and independently predicted LC (hazard ratio, 0.14; P = .01). Sixteen radiation-naive patients (24%) experienced acute grade 3 toxicities; 4 (6%) experienced late grade 3 toxicities (osteoradionecrosis, vision loss, soft-tissue necrosis, and soft tissue fibrosis) (grading was performed according to the National Cancer Institute Common Terminology Criteria for Adverse Events [version 5.0]). Slightly inferior LC was noted for patients undergoing reirradiation with higher complications: 11% experienced late grade 3 toxicities (facial pain and brain necrosis). Patients treated with reirradiation had more grade 1 to 2 radionecrosis than radiation-naive patients (brain: 33% vs 7% and osteoradionecrosis: 17% vs 3%). CONCLUSIONS: PT achieved remarkable LC for patients with nasal cavity and paranasal sinus cancers with lower grade 3 toxicities relative to historical reports. IMPT has the potential to improve the therapeutic ratio in these malignancies and is worthy of further investigation.

4.
J Am Chem Soc ; 142(4): 1864-1870, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31884789

RESUMO

Single-crystal cryogenic X-ray diffraction at 6 K, electron paramagnetic resonance spectroscopy, and correlated electronic structure calculations are combined to shed light on the nature of the metal-tris(aryloxide) and η2-H, C metal-alkane interactions in the [((t·BuArO)3tacn)UIII(Mecy-C6)]·(Mecy-C6) adduct. An analysis of the ligand field experienced by the uranium center using ab initio ligand field theory in combination with the angular overlap model yields rather unusual U-OArO and U-Ntacn bonding parameters for the metal-tris(aryloxide) interaction. These parameters are incompatible with the concept of σ and π metal-ligand overlap. For that reason, it is deduced that metal-ligand bonding in the [((t·BuArO)3tacn)UIII] moiety is predominantly ionic. The bonding interaction within the [((t·BuArO)3tacn)UIII] moiety is shown to be dispersive in nature and essentially supported by the upper-rim tBu groups of the (t·BuArO)3tacn3- ligand. Our findings indicate that the axial alkane molecule is held in place by the guest-host effect rather than direct metal-alkane ionic or covalent interactions.

5.
J Exp Biol ; 222(Pt 21)2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31586019

RESUMO

The widespread ability to alter timing of hatching in response to environmental cues can serve as a defense against threats to eggs. Arboreal embryos of red-eyed treefrogs, Agalychnis callidryas, can hatch up to 30% prematurely to escape predation. This escape-hatching response is cued by physical disturbance of eggs during attacks, including vibrations or motion, and thus depends critically on mechanosensory ability. Predator-induced hatching appears later in development than flooding-induced, hypoxia-cued hatching; thus, its onset is not constrained by the development of hatching ability. It may, instead, reflect the development of mechanosensor function. We hypothesize that vestibular mechanoreception mediates escape-hatching in snake attacks, and that the developmental period when hatching-competent embryos fail to flee from snakes reflects a sensory constraint. We assessed the ontogenetic congruence of escape-hatching responses and an indicator of vestibular function, the vestibulo-ocular reflex (VOR), in three ways. First, we measured VOR in two developmental series of embryos 3-7 days old to compare with the published ontogeny of escape success in attacks. Second, during the period of greatest variation in VOR and escape success, we compared hatching responses and VOR across sibships. Finally, in developmental series, we compared the response of individual embryos to a simulated attack cue with their VOR. The onset of VOR and hatching responses were largely concurrent at all three scales. Moreover, latency to hatch in simulated attacks decreased with increasing VOR. These results are consistent with a key role of the vestibular system in the escape-hatching response of A. callidryas embryos to attacks.

6.
Chem Sci ; 10(30): 7233-7245, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31588292

RESUMO

Lanthanide ions when complexed by polyamino-polycarboxylate chelators form a class of compounds of paramount importance in several research and technological areas, particularly in the fields of magnetic resonance and molecular magnetism. Indeed, the gadolinium derivative is one of the most employed contrast agents for magnetic resonance imaging while the dysprosium one belongs to a new generation of contrast agents for T2-weighted MRI. In molecular magnetism, Single Molecule Magnets (SMMs) containing lanthanide ions have become readily popular in the chemistry and physics communities since record energy barriers to the reversal of magnetization were reported. The success of lanthanide complexes lies in their large anisotropy due to the contribution of the unquenched orbital angular momentum. However, only a few efforts have been made so far to understand how the f-orbitals can be influenced by the surrounding ligands. The outcomes have been rationalized using mere electrostatic perturbation models. In the archetype compound [Na{Dy(DOTA) (H2O)}]·4H2O (Na{DyDOTA}·4H2O) an unexpected easy axis of magnetization perpendicular to the pseudo-tetragonal axis of the molecule was found. Interestingly, a dependency of the orientation of the principal magnetization axis on the simple rotation of the coordinating apical water molecule (AWM) - highly relevant for MRI contrast - around the Dy-OAWM bond was predicted by ab initio calculations, too. However, such a behaviour has been contested in a subsequent paper justifying their conclusions on pure electrostatic assumptions. In this paper, we want to shed some light on the nature of the subtle effects induced by the water molecule on the magnetic properties of the DyDOTA archetype complex. Therefore, we have critically reviewed the structural models already published in the literature along with new ones, showing how the easy axis orientation can dangerously depend on the chosen model. The different computed behaviors of the orientation of the easy axis of magnetization have been rationalized as a function of the energy gap between the ground and the first excited doublet. Magneto-structural correlations together with a mapping of the electrostatic potential generated by the ligands around the Dy(iii) ion through a multipolar expansion have also been used to evidence and quantify the covalent contribution of the AWM orbitals.

7.
Chemistry ; 25(66): 15112-15122, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31496013

RESUMO

Two series of lanthanide complexes have been chosen to analyze trends in the magnetic properties and crystal field parameters (CFPs) along the two series: The highly symmetric LnZn16 (picHA)16 series (Ln=Tb, Dy, Ho, Er, Yb; picHA=picolinohydroxamic acid) and the [Ln(dpa)3 ](C3 H5 N2 )3 ⋅3H2 O series (Ln=Ce-Yb; dpa=2,6-dipicolinic acid) with approximate three-fold symmetry. The first series presents a compressed coordination sphere of eight oxygen atoms whereas in the second series, the coordination sphere consists of an elongated coordination sphere formed of six oxygen atoms. The CFPs have been deduced from ab initio calculations using two methods: The AILFT (ab initio ligand field theory) method, in which the parameters are determined at the orbital level, and the ITO (irreducible tensor operator) decomposition, in which the problems are treated at the many-electron level. It has been found that the CFPs are transferable from one derivative to another, within a given series, as a first approximation. The sign of the second-order parameter B 0 2 differs in the two series, reflecting the different environments. It has been found that the use of the strength parameter S allows for an easy comparison between complexes. Furthermore, in both series, the parameters have been found to decrease in magnitude along the series, and this decrease is attributed to covalent effects.

8.
Am J Drug Alcohol Abuse ; 44(5): 551-560, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29286835

RESUMO

BACKGROUND: Alcohol and drug use is associated with significant morbidity and mortality and is highly prevalent among homeless youth. Ecological Momentary Assessments (EMA) have been used to examine the effect of urges on drug use, though not among homeless youth. OBJECTIVES: We assessed the patterns of drug use and the correlation between real-time contextual factors and drug use using EMA collected daily. We identified predictors of drug use among a sample of homeless youth 18-25 years old in Houston, Texas. METHODS: Homeless youth (n = 66, 62% male) were recruited from a drop-in center between September 2015 and May 2016. We used generalized linear mixed models and cross-validation methods to determine the best predictive model of drug use. RESULTS: The overall drug use was high: 61% and 32% of participants reported using drugs or alcohol at least one day, respectively. Marijuana and synthetic marijuana use (i.e., Kush, K2, incense packs) were reported most frequently; 86% and 13% of the total drug use EMAs, respectfully. Drug use urge was reported on 26% of days and was the highest on drug use days. Drug use was predicted by discrimination, pornography use, alcohol use, and urges for drugs, alcohol, and to steal. CONCLUSIONS: EMA can be used to predict drug use among homeless youth. Drug use treatment among homeless youth should address the role of experiencing discrimination, pornography and alcohol use, and urge management strategies on drug use. Research is needed to determine if EMA informed just-in-time interventions targeting these predictors can reduce use.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Avaliação Momentânea Ecológica , Jovens em Situação de Rua/estatística & dados numéricos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Adolescente , Adulto , Literatura Erótica/psicologia , Feminino , Humanos , Modelos Lineares , Masculino , Uso da Maconha/epidemiologia , Modelos Teóricos , Discriminação Social/psicologia , Texas/epidemiologia , Adulto Jovem
9.
Eur Urol Oncol ; 1(5): 378-385, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-31158076

RESUMO

BACKGROUND: Ultrasensitive prostate-specific antigen (uPSA) has untapped potential for optimizing management following radical prostatectomy (RP) in terms of facilitating early salvage, minimizing overtreatment, and identifying those at risk of occult systemic disease. OBJECTIVE: To test first postoperative uPSA for prediction of outcome in patients with adverse pathology after RP. DESIGN, SETTING, AND PARTICIPANTS: Patients with extraprostatic extension and/or a positive margin who did not receive immediate adjuvant therapy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: First uPSA was measured at 3 mo after RP. The study endpoints were biochemical relapse (BCR), defined as PSA ≥0.2ng/ml, bone metastasis-free survival (BMFS), prostate cancer-specific survival (PCSS), overall survival (OS), and salvage radiation therapy (SRT) success. Outcome results were compared using the Kaplan-Meier method and multivariate analysis (MVA). RESULTS AND LIMITATIONS: The cohort consisted of 269 RP patients from 1991-2015 with median follow-up of 77 mo. Sensitivity analysis identified first postoperative uPSA of ≥0.03ng/ml as the optimal threshold for predicting BCR. First postoperative uPSA ≥0.03 versus <0.03ng/ml was associated with worse 5-yr BCR (86%, 95% confidence interval [CI] 71-93% vs 39%, 95% CI 25-51%; p<0.00001), 10-yr BMFS (75%, 95% CI 62-92% vs 95%, 95% CI 88-100%; p=0.0001), 10-yr PCSS (84%, 95% CI 73-96% vs 100%, 95% CI 100-100%; p=0.005), and 10-yr OS (81%, 95% CI 70-93% vs 98%, 95% CI 94-100%; p=0.009). On MVA, first postoperative uPSA ≥0.03ng/ml was an independent predictor of BCR (hazard ratio [HR] 9.4, 95% CI 5.8-15.4; p<0.00001) and the only predictor for BMFS (HR 9.7, 95% CI 2.1-44.6; p=0.0034), PCSS (HR 13.5, 95% CI 1.7-107.9; p=0.014), and OS (HR 5.0, 95% CI 1.4-18.3; p=0.014). Following SRT, first postoperative uPSA ≥0.03ng/ml independently predicted worse BMFS (HR 5.9, 95% CI 1.3-26.9; p=0.021), PCSS (HR 6.9, 95% CI 0.9-55.8; p=0.07), and OS (4.5, 95% CI 1.0-20.1; p=0.057). Limitations include the retrospective design and potential selection bias. CONCLUSIONS: First postoperative uPSA ≥0.03ng/ml independently predicts BCR, BMFS, PCSS, and OS better than traditional risk factors. SRT alone may be insufficient for patients with high-risk disease when first postoperative uPSA is ≥0.03ng/ml. PATIENT SUMMARY: When the first postprostatectomy ultrasensitive prostate-specific antigen level is ≥0.03ng/ml, patients are at higher risk of recurrent and occult prostate cancer. They should be considered for early salvage radiotherapy, possibly with hormone therapy.


Assuntos
Antígeno Prostático Específico/sangue , Prostatectomia , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , Idoso , Seguimentos , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/diagnóstico , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/radioterapia , Estadiamento de Neoplasias , Neoplasia Residual , Período Pós-Operatório , Prognóstico , Antígeno Prostático Específico/análise , Neoplasias da Próstata/diagnóstico , Radioterapia Adjuvante/estatística & dados numéricos , Estudos Retrospectivos , Fatores de Risco , Terapia de Salvação/estatística & dados numéricos , Análise de Sobrevida
10.
Inorg Chem ; 56(15): 8802-8816, 2017 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-28708410

RESUMO

Actinide chemistry is gaining increased focus in modern research, particularly in the fields of energy research and molecular magnetism. However, the structure-function and structure-property relationships of actinides have still not been studied as intensely as those for transition metals. In this work, we report a detailed ab initio study of the spectroscopic, magnetic, and bonding properties of the trivalent actinide free ions and their associated hexachloride complexes in octahedral symmetry. The electronic structures of these systems are examined using complete active-space self-consistent-field calculations followed by second-order N-electron valence perturbation theory, including both scalar relativistic and spin-orbit-coupling effects. The computed energies and wave functions are further analyzed by means of ab initio ligand-field theory (AILFT) and finally chemically interpreted by means of the angular overlap model (AOM). The derived Slater-Condon and spin-orbit parameters have allowed us to systematically rationalize the spectroscopic and magnetic properties of the investigated free ions and complexes along the entire actinide series. Overall, the AILFT- and AOM-derived parameters accurately reproduce the multireference electronic structure calculations. The small observed discrepancies with respect to experimentally derived ligand-field parameters are essentially due to an underestimation of the electronic correlation, which arises from both the constrained size of the active space (restricted to the f orbitals) and the limit of the perturbation approach to account for dynamical correlation. Our analysis also provides insight into the metal-ligand covalency trends along the series. Consistent with natural population analysis, the nephelauxetic (Slater-Condon parameters) and relativistic nephelauxetic (spin-orbit-coupling) reductions determined for these complexes indicate a decrease in the covalency along the series. These trends also hold, to varying extents, for the corresponding tetravalent derivatives, as well as the lanthanide analogues.

11.
Inorg Chem ; 56(12): 6788-6801, 2017 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-28558238

RESUMO

We report a combined theoretical and experimental investigation of the exchange interactions governing the magnetic behavior of a series of nitronyl nitroxide (NIT)-based Y(III) complexes, i.e., Y(hfac)3(NIT-R)2 with R = PhOPh (1), PhOEt (2), and PhOMe (3a, 3b). Even though some of these complexes or their Dy(III) parents were previously described in the literature [ Zhao et al. Transition Met. Chem. 2006 , 31 , 593 ; Bernot et al. J. Am. Chem. Soc. 2009 , 131 , 5573 ], their synthesis procedure as well as their structural and magnetic properties were completely reconsidered. Depending on the nature of R and the crystallization conditions, Y(hfac)3(NIT-R)2 units can be organized as supramolecular dimers or linear or orthogonal chains. Such structural diversity within the series induces extremely different magnetic behaviors. The observed behaviors are rationalized by state-of-the-art wave function-based quantum-chemical approaches (CASSCF/DDCI) that demonstrate the existence of not only effective intramolecular interactions between the NIT-R radical ligands of an isolated Y(hfac)3(NIT-R)2 molecule but also intermolecular interactions between NIT-R moieties belonging to different Y(hfac)3(NIT-R)2 units. These results are supported by the use of spin Hamiltonian models going beyond the basic Bleaney-Bowers formalism to properly fit the experimental magnetic data. Finally, the microscopic mechanisms behind the evidenced intramolecular exchange interactions are elucidated through the inspection of the calculated wave functions. In particular, whereas the role of Y orbitals was already proposed, we herein demonstrate the contribution of the hfac- ancillary ligands in mediating the magnetic interactions between the NIT radicals.

12.
Inorg Chem ; 55(4): 1905-11, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26812039

RESUMO

The magnetic relaxation and anisotropy of 3- and 4-coordinate lanthanide complexes were systematically investigated, and the change of SMM behavior originating from the equatorially coordinating ligand field was successfully elucidated through combined experimental and theoretical studies. Remarkably, a novel approach taking into account the different contributions of atomic charges, dipole moments, and quadrupole moments was used to map the electrostatic potential around the metal center in the Dy(III) derivatives, revealing the key role played by the ligands as a whole and not just by the coordinating donor atoms as often considered.

13.
Chem Sci ; 7(6): 3632-3639, 2016 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30008995

RESUMO

Geometry and magnetic relaxation modulations in a series of mononuclear dysprosium complexes, [DyLz2(o-vanilin)2]·X·solvent (Lz = 6-pyridin-2-yl-[1,3,5]triazine-2,4-diamine; X = Br- (1), NO3- (2), CF3SO3- (3)), were realized by changing the nature of the counter-anion. The DyIII ions in all complexes are eight-coordinate and in approximate D4d symmetry environments. The magnetic relaxation and anisotropy of these complexes were systematically investigated, both experimentally and from ab initio calculations. All complexes exhibit excellent single-molecule magnetic behavior. Remarkably, magneto-structural studies show that the rotation of the coordinating plane of the square-antiprismatic environment in complex 2 induces a magnetic relaxation path through higher excited states, yielding a high anisotropy barrier of 615 K (696 K for a diluted sample). Additionally, obvious opening of the hysteresis loop is observed up to 7 K, which is the highest blocking temperature ever reported for dysprosium single-molecule magnets.

14.
Chemistry ; 22(4): 1392-8, 2016 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-26670125

RESUMO

Elaborate chemical design is of utmost importance in order to slow down the relaxation dynamics in single-molecule magnets (SMMs) and hence improve their potential applications. Much interest was devoted to the study of distinct relaxation processes related to the different crystal fields of crystallographically independent lanthanide ions. However, the assignment of the relaxation processes to specific metal sites remains a challenging task. To address this challenge, a new asymmetric Dy2 SMM displaying a well-separated two-step relaxation process with the anisotropic centers in fine-tuned local environments was elaborately designed. For the first time a one-to-one relationship between the metal sites and the relaxation processes was evidenced. This work sheds light on complex multiple relaxation and may direct the rational design of lanthanide SMMs with enhanced magnetic properties.

15.
Inorg Chem ; 54(16): 7673-83, 2015 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-26208250

RESUMO

[Mo6X14](2-) octahedral molybdenum clusters are the main building blocks of a large range of materials. Although (95)Mo nuclear magnetic resonance was proposed to be a powerful tool to characterize their structural and dynamical properties in solution, these measurements have never been complemented by theoretical studies which can limit their interpretation for complex systems. In this Article, we use quantum chemical calculations to evaluate the (95)Mo chemical shift of three clusters: [Mo6Cl14](2-), [Mo6Br14](2-), and [Mo6I14](2-). In particular, we test various computational parameters influencing the quality of the results: size of the basis set, treatment of relativistic and solvent effects. Furthermore, to provide quantum chemical calculations that are directly comparable with experimental data, we evaluate for the first time the (95)Mo nuclear magnetic shielding of the experimental reference, namely, MoO4(2-) in aqueous solution. This is achieved by combining ab initio molecular dynamics simulations with a periodic approach to evaluate the (95)Mo nuclear shieldings. The results demonstrate that, despite the difficulty to obtain accurate (95)Mo chemical shifts, relative values for a cluster series can be fairly well-reproduced by DFT calculations. We also show that performing an explicit solvent treatment for the reference compound improves by ∼50 ppm the agreement between theory and experiment. Finally, the standard deviation of ∼70 ppm that we calculate for the (95)Mo nuclear shielding of the reference provides an estimation of the accuracy we can achieve for the calculation of the (95)Mo chemical shifts using a static approach. These results demonstrate the growing ability of quantum chemical calculations to complement and interpret complex experimental measurements.


Assuntos
Molibdênio/química , Teoria Quântica , Isótopos , Espectroscopia de Ressonância Magnética , Conformação Molecular , Simulação de Dinâmica Molecular , Solventes/química
16.
Inorg Chem ; 54(14): 6891-9, 2015 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-26125503

RESUMO

The gradual magnetostructural transition in breathing crystals based on copper(II) and pyrazolyl-substituted nitronyl nitroxides has been analyzed by means of DDCI quantum chemistry calculations. The magnetic coupling constants (J) within the spin triads of Cu(hfac)2L(Bu)·0.5C8H18 have been evaluated for the X-ray structures reported at different temperatures. The coupling is strongly antiferromagnetic at low temperature and becomes ferromagnetic when the temperature increases. The intercluster magnetic coupling (J') is antiferromagnetic and shows a marked dependence on temperature. The magnetostructural transition can be reproduced using the calculated J values for each structure in the simulation of the magnetic susceptibility. However, the µ(T) curve can be improved nicely by considering the coexistence of two phases in the transition region, whose ratio varies with temperature corresponding to both the weakly and strongly coupled spin states. These results complement a recent VT-FTIR study on the parent Cu(hfac)2L(Pr) compound with a gradual magnetostructural transition.

17.
Inorg Chem ; 54(11): 5384-97, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-25965094

RESUMO

The reaction between the TTF-fused dipyrido[3,2-a:2',3'-c]phenazine (dppz) ligand (L) and 1 equiv of Ln(hfac)3·2H2O (hfac(-) = 1,1,1,5,5,5-hexafluoroacetyacetonate) or 1 equiv of Ln(tta)3·2H2O (tta(-) = 2-thenoyltrifluoroacetonate) (Ln(III) = Dy(III) or Yb(III)) metallic precursors leads to four mononuclear complexes of formula [Ln(hfac)3(L)]·C6H14 (Ln(III) = Dy(III) (1), Yb(III) (2)) and [Ln(tta)3(L)]·C6H14 (Ln(III) = Dy(III) (3), Yb(III) (4)), respectively. Their X-ray structures reveal that the Ln(III) ion is coordinated to the bischelating nitrogenated coordination site and adopts a D4d coordination environment. The dynamic magnetic measurements show a slow relaxation of the Dy(III) magnetization for 1 and 3 with parameters highlighting a slower relaxation for 3 than for 1 (τ0 = 4.14(±1.36) × 10(-6) and 1.32(±0.07) × 10(-6) s with Δ = 39(±3) and 63.7(±0.7) K). This behavior as well as the orientation of the associated magnetic anisotropy axes have been rationalized on the basis of both crystal field splitting parameters and ab initio SA-CASSCF/RASSI-SO calculations. Irradiation of the lowest-energy HOMO → LUMO ILCT absorption band induces a (2)F5/2 → (2)F7/2 Yb-centered emission for 2 and 4. For these Yb(III) compounds, Stevens operators method has been used to fit the thermal variation of the magnetic susceptibilities, and the resulting MJ splittings have been correlated with the emission lines.

18.
J Urol ; 193(5): 1532-8, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25463990

RESUMO

PURPOSE: Integrating ultrasensitive prostate specific antigen with surveillance in patients at high risk after radical prostatectomy potentially optimizes treatment by correctly identifying recurrence, promoting an early salvage strategy and minimizing overtreatment. We tested the power of postoperative ultrasensitive prostate specific antigen to identify eventual biochemical failure. MATERIALS AND METHODS: We identified 247 patients at high risk with a median followup of 44 months who underwent radical prostatectomy from 1991 to 2013. Each patient had extraprostatic extension and/or a positive margin. Surgical technique, initial prostate specific antigen, pathology findings and postoperative prostate specific antigen were analyzed. The ultrasensitive prostate specific antigen assay threshold was 0.01 ng/ml. Conventional biochemical relapse was defined as prostate specific antigen 0.2 ng/ml or greater. Kaplan-Meier and Cox multivariate analyses were done to compare the rates of ultrasensitive prostate specific antigen recurrence and conventional biochemical relapse. RESULTS: Sensitivity analysis revealed that ultrasensitive prostate specific antigen 0.03 ng/ml or greater was the optimal threshold to identify recurrence. A first postoperative ultrasensitive value of 0.03 ng/ml or greater, Gleason grade, T stage, initial prostate specific antigen and margin status predicted conventional biochemical relapse. On multivariate analysis only a first postoperative ultrasensitive value of 0.03 ng/ml or greater, Gleason grade and T stage independently predicted conventional biochemical relapse. First postoperative ultrasensitive prostate specific antigen 0.03 ng/ml or greater conferred the highest risk (HR 8.5, p < 0.0001) and identified conventional biochemical relapse with greater sensitivity than undetectable first conventional prostate specific antigen (70% vs 46%). Any postoperative prostate specific antigen 0.03 ng/ml or greater captured all failures missed by the first postoperative value (100% sensitivity) with accuracy (96% specificity). Defining failure at an ultrasensitive value of 0.03 ng/ml or greater yielded a median lead time advantage of 18 months (mean 24) over the conventional definition of prostate specific antigen 0.2 ng/ml or greater. CONCLUSIONS: Ultrasensitive prostate specific antigen 0.03 ng/ml or greater is an independent factor that identifies biochemical relapse more accurately than any traditional risk factors and confers a significant lead time advantage. This factor enables critical decisions on the timing of and indication for postoperative radiotherapy in patients at high risk after radical prostatectomy.


Assuntos
Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/radioterapia , Antígeno Prostático Específico/sangue , Prostatectomia , Neoplasias da Próstata/radioterapia , Neoplasias da Próstata/cirurgia , Humanos , Masculino , Recidiva Local de Neoplasia/diagnóstico , Seleção de Pacientes , Cuidados Pós-Operatórios , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade
19.
Chem Commun (Camb) ; 50(87): 13346-8, 2014 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-25233443

RESUMO

Magnetic slow relaxation is observed in a Dy(III)-based molecular chain and the magnetic easy-axis is determined via single-crystal magnetometry. Ab initio calculations confirm its orientation and highlight that the latter is governed neither by coordination polyhedron symmetry nor by the chain direction but rather by the single-ion electrostatic environment, a feature that is confirmed by a similar theoretical analysis on other Dy(III) chains.

20.
Chemistry ; 20(6): 1569-76, 2014 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-24402683

RESUMO

Herein, we provide some structural evidence of the complexation color-change of murexide solutions in presence of lanthanide, which has been used for decades in complexometric studies. For Ln = Sm to Lu and Y, the compounds crystallize as monomeric [Ln(Murex)3]⋅11 H2O with an N3O6 tricapped square-antiprism environment, which are stable up to 250 °C. Single-ion magnet (SIM) behavior is then observed on the Yb(III) derivative in an original nine-coordinated environment. In-field slow relaxation (Δ = (15.6±1) K; τ0 = 2.73×10(-6) s) is observed with a very narrow distribution of the relaxation time (αmax = 0.09). Magnetic and photophysical properties can be correlated. On one hand the analysis of NIR emission spectrum permits to have access to crystal field parameters and to compare them with those extracted from dc measurements. On the other hand, magnetic measurements permit to identify the nature of the MJ states involved in the (2)F5/2 → (2)F7/2 luminescence spectrum. The gap between the low-lying states is in agreement with the energy barrier obtained from magnetic slow-relaxation measurement.

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