Vibron-assisted spin excitation in a magnetically anisotropic molecule.

The electrical control and readout of molecular spin states are key for high-density storage. Expectations are that electrically-driven spin and vibrational excitations in a molecule should give rise to new conductance features in the presence of magnetic anisotropy, offering alternative routes to study and, ultimately, manipulate molecular magnetism. Here, we use inelastic electron tunneling spectroscopy to promote and detect the excited spin states of a prototypical molecule with magnetic anisotropy. We demonstrate the existence of a vibron-assisted spin excitation that can exceed in energy and in amplitude a simple excitation among spin states. This excitation, which can be quenched by structural changes in the magnetic molecule, is explained using first-principles calculations that include dynamical electronic correlations.

Health questionnaire analysis and development of satisfaction questionnaire for patients treated with extracorporeal shock wave lithotripsy (SATISLIT). / Análisis de cuestionario de salud y desarrollo de cuestionario de satisfacción en pacientes tratados con litotricia extracorpórea por ondas de choque (SATISLIT).

INTRODUCTION: Due to the absence of specific instruments to study the psychosocial sphere of patients undergoing extracorporeal shock wave lithotripsy (SWL), the objective of this study is to develop a satisfaction questionnaire regarding the SWL treatment from a health questionnaire which was already designed and had been previously validated. MATERIAL AND METHODS: The design of the satisfaction questionnaire was carried out in 5 phases, based on a previously validated health scale in patients treated with SWL (ESPTL), including a total cohort of 135 patients treated at our center who received a phone interview. Phase 1: descriptive analysis of the series and scores of the 8 items of ESPTL. Phase 2: U-Mann Whitney comparison of ESPTL based on the patients' sex. Phase 3: study of ESPTL correlation with age using Spearman's Rho. Phase 4: grouping by factors of ESPTL, comparison by sex and correlation with age, as performed in phases 2 and 3 with the global score. Phase 5: obtaining the satisfaction subscale -SATISLIT-, descriptive analysis, comparison according to sex, correlation with age and linear regression model of SATISLIT with respect to ESPTL. RESULTS: 135 patients, 85(63%) men, 50(37%) women. Median (minimum-maximum) age 56 (27-79) and ESPTL score 31 (8-39). Differences in global ESPTL score between men and women (p <.001), as well as in items 1 (p =.029), 3 (p =.002), 6 (p =.006), 7 (p =.005) and 8 (p =.025). Non-significant correlation of ESPTL regarding age. Significant correlation in items 2, 4, 5 and 8 but, very weak (<0.2). 4 factors, each one with 2 items, with statistically significant differences regarding sex in F2 (p =.001), F3 (p =.007) and F4 (p =.001). Significant correlation with age only in F1 and F3, but very weak (<0.2). Median (minimum-maximum) SATISLIT 18 (4-20). Statistically significant differences regarding patients' sex (p =.001). Non- significant correlation with age (p =.836). Significant linear regression of SATISLIT with respect to ESPTL (p <.001). CONCLUSIONS: Based on validated health questionnaire, the present work has provided a new instrument called SATISLIT for assessing patients' satisfaction after treatment with SWL. Future studies with external and temporal validation will be necessary to contrast its real clinical usefulness.

Risk models for patients with localised renal cell carcinoma. / Modelos de riesgo en pacientes con carcinoma de células renales localizado.

INTRODUCTION: We conducted a retrospective analysis of our series to assess the factors that influenced disease-free survival (DFS) and cancer-specific survival (CSS) for patients with localised renal cell carcinoma (RCC). We also created our own risk groups. MATERIAL AND METHODS: Between January 1990 and December 2012, 596 patients underwent surgery for localised RCC (clear cell, papillary or chromophobe). Using Cox regression models, we analysed the clinical-pathological variables that influenced DFS and CSS and designed risk groups for DFS and CSS with the variables. RESULTS: The median follow-up for the series was 5.96 years. By the end of the study, 112 patients (18.8%) had a recurrence of the disease, with DFS rates of 82%, 77% and 72% at 5, 10 and 15 years, respectively. The independent factors that influenced DFS in the multivariate study were the following: A Furhman grade of 3-4, haematuria, lymphocytic or vascular invasion, the presence of tumour necrosis and a disease stage pT3-pT4. Furthermore, by the end of the study, 57 patients (9.6%) died due to renal cancer, with CSS rates of 92%, 86% and 83% at 5, 10 and 15 years, respectively. The independent factors that influenced CSS in the multivariate study were the following: A Furhman grade of 3-4, perinephric fat invasion and the presence of tumour necrosis. CONCLUSIONS: Factors in addition to the disease stage pT3-pT4 in patients with localised RCC are important, such as the presence of haematuria and lymphocytic or vascular invasion for DFS. A Furhman grade of 3-4 and the presence of tumour necrosis are especially relevant for DFS and CSS.

Predicting the effectiveness of extracorporeal shock wave lithotripsy on urinary tract stones. Risk groups for accurate retreatment. / Predicción de efectividad de litotricia extracorpórea por ondas de choque en cálculos del tracto urinario. Grupos de riesgo para precisar retratamiento.

INTRODUCTION: Extracorporeal shock wave lithotripsy (ESWL) is a non-invasive, safe and effective treatment for urinary tract lithiasis. Its effectiveness varies depending on the location and size of the stones as well as other factors; several sessions are occasionally required. The objective is to attempt to predict its success or failure, when the influential variables are known beforehand. MATERIAL AND METHODS: We analysed 211 patients who had had previous CT scans and were treated with ESWL between 2010 and 2014. The influential variables in requiring retreatment were studied using binary logistic regression models (univariate and multivariate analysis): maximum density, maximum diameter, area, location, disintegration and distance from the adipose panniculus. With the influential variables, a risk model was designed by assessing all possible combinations with logistic regression (version 20.0 IBM SPSS). RESULTS: The independent influential variables on the need for retreatment are: maximum density >864HU, maximum diameter >7.5mm and pyelocaliceal location. Using these variables, the best model includes 3risk groups with a probability of requiring significantly different retreatment: group 1-low risk (0 variables) with 20.2%; group 2-intermediate risk (1-2 variables) with 49.2%; and group 3-high risk (3 variables) with 62.5%. CONCLUSIONS: The density, maximum diameter and pyelocaliceal location of the stones are determinant factors in terms of the effectiveness of treatment with ESWL. Using these variables, which can be obtained in advance of deciding on a treatment, the designed risk model provides a precise approach in choosing the most appropriate treatment for each particular case.

Charged and metallic molecular monolayers through surface-induced aromatic stabilization.

Large π-conjugated molecules, when in contact with a metal surface, usually retain a finite electronic gap and, in this sense, stay semiconducting. In some cases, however, the metallic character of the underlying substrate is seen to extend onto the first molecular layer. Here, we develop a chemical rationale for this intriguing phenomenon. In many reported instances, we find that the conjugation length of the organic semiconductors increases significantly through the bonding of specific substituents to the metal surface and through the concomitant rehybridization of the entire backbone structure. The molecules at the interface are thus converted into different chemical species with a strongly reduced electronic gap. This mechanism of surface-induced aromatic stabilization helps molecules to overcome competing phenomena that tend to keep the metal Fermi level between their frontier orbitals. Our findings aid in the design of stable precursors for metallic molecular monolayers, and thus enable new routes for the chemical engineering of metal surfaces.

Reversible change of the spin state in a manganese phthalocyanine by coordination of CO molecule.

We show that the magnetic state of individual manganese phthalocyanine (MnPc) molecules on a Bi(110) surface is modified when the Mn2+ center coordinates to CO molecules adsorbed on top. Using scanning tunneling spectroscopy we identified this change in magnetic properties from the broadening of a Kondo-related zero-bias anomaly when the CO-MnPc complex is formed. The original magnetic state can be recovered by selective desorption of individual CO molecules. First principles calculations show that the CO molecule reduces the spin of the adsorbed MnPc from S=1 to S=1/2 and strongly modifies the respective screening channels, driving a transition from an underscreened Kondo state to a state of mixed valence.

Reversible electron-induced cis-trans isomerization mediated by intermolecular interactions.

Reversible isomerization processes are rarely found when organic molecular switches are adsorbed on metal surfaces. One obstacle is the large energy difference of the isomeric forms, since usually the most planar conformer has the largest adsorption energy. In the example of an imine derivative, we show a strategy for also stabilizing the non-planar isomer by intermolecular bonding to its neighbors. Tunneling electrons from the tip of a scanning tunneling microscope can then be used to induce reversible switching between the trans and cis-like state. Supported by model force-field calculations, we illustrate that the most probable cause of the enhanced stability of the three-dimensional cis state at specific adsorption sites is the electrostatic interaction with N sites of the neighboring molecule.

Enhanced charge transfer in a monolayer of the organic charge transfer complex TTF-TNAP on Au(111).

Electronic doping is a key concept for tuning the properties of organic materials. In bulk structures, the charge transfer between donor and acceptor is mainly given by the respective ionization potential and electron affinity. In contrast, monolayers of charge transfer complexes in contact with a metal are affected by an intriguing interplay of hybridization and screening at the metallic interface, determining the resulting charge state. Using scanning tunneling microscopy and spectroscopy, we characterize the electronic properties of the organic acceptor molecule 11,11,12,12-tetracyanonaptho-2,6-quinodimethane (TNAP) adsorbed on a Au(111) surface. The ordered islands remain in a weakly physisorbed state with no charge transfer interaction with the substrate. When the electron donor tetrathiafulvalene (TTF) is added, ordered arrays of alternating TNAP and TTF rows are assembled. In these structures, we find the lowest unoccupied molecular orbital (LUMO) of the free TNAP molecule shifted well below the Fermi level of the substrate. The TNAP is thus charged with more than one electron.

Gating the charge state of single molecules by local electric fields.

The electron-acceptor molecule TCNQ is found in either of two distinct integer charge states when embedded into a monolayer of a charge transfer complex on a gold surface. Scanning tunneling spectroscopy measurements identify these states through the presence or absence of a zero-bias Kondo resonance. Increasing the (tip-induced) electric field allows us to reversibly induce the oxidation or reduction of TCNQ species from their anionic or neutral ground state, respectively. We show that the different ground states arise from slight variations in the underlying surface potential, pictured here as the gate of a three-terminal device.

Ferromagnetic coupling of mononuclear Fe centers in a self-assembled metal-organic network on Au(111).

The magnetic state and magnetic coupling of individual atoms in nanoscale structures relies on a delicate balance between different interactions with the atomic-scale surroundings. Using scanning tunneling microscopy, we resolve the self-assembled formation of highly ordered bilayer structures of Fe atoms and organic linker molecules (T4PT) when deposited on a Au(111) surface. The Fe atoms are encaged in a three-dimensional coordination motif by three T4PT molecules in the surface plane and an additional T4PT unit on top. Within this crystal field, the Fe atoms retain a magnetic ground state with easy-axis anisotropy, as evidenced by x-ray absorption spectroscopy and x-ray magnetic circular dichroism. The magnetization curves reveal the existence of ferromagnetic coupling between the Fe centers.

Competition of superconducting phenomena and Kondo screening at the nanoscale.

Magnetic and superconducting interactions couple electrons together to form complex states of matter. We show that, at the atomic scale, both types of interactions can coexist and compete to influence the ground state of a localized magnetic moment. Local spectroscopy at 4.5 kelvin shows that the spin-1 system formed by manganese-phthalocyanine (MnPc) adsorbed on Pb(111) can lie in two different magnetic ground states. These are determined by the balance between Kondo screening and superconducting pair-breaking interactions. Both ground states alternate at nanometer length scales to form a Moiré-like superstructure. The quantum phase transition connecting the two (singlet and doublet) ground states is thus tuned by small changes in the molecule-lead interaction.

[Study on the findings of an immediate renal gammagraphy and its effect on the survival of a kidney graft]. / Estudio de los hallazgos de la gammagrafía renal inmediata y su influencia en la supervivencia del injerto renal.

INTRODUCTION: We assessed the effect of the findings of the renal gammagraphy (99mTc-DTPA) taken in the first 24 hours after the transplant in the survival of the kidney transplant. MATERIALS AND METHOD: We retrospectively studied 413 kidney transplants carried out between January 1994 and December 2008, with emphasis on normal gammagraphic findings or alterations in the vascular, parenchymal and excretory stages, as well as their effect on the survival of the graft. RESULTS: Of the 413 transplants, 44 (10.7%) presented alterations in the vascular stage, 256 (62%) in the parenchymal stage and 269 (65.1%) in the excretory stage. The mean follow-up of the entire group was 72.5 months (± 54.1 DE). The univariate analysis shows that the survival of the graft is significantly less in patients with alterations in the vascular stage (OR: 3; IC 95% 1.9 - 4.9 p<0.001), in the excretory stage (OR: 2.5; IC 95% 1.5 - 4; p=<0.001) in the parenchymal stage (OR: 2.21; IC 95% 1.3-3.36; p=0.001). The multivariate studies of the gammagraphic variables that affect the survival of the graft show that the presence of alterations in the vascular stage (OR: 3; IC 95% 1.9-4.9; p<0.001) in the parenchymal stage (OR: 2; IC 95% 1.2-3.3; p=0.005) are directly related to survival. This data is also confirmed by means of the actuarial survival analysis of the graft at 3 and 5 years. CONCLUSIONS: The presence of alterations in the vascular stage and in the parenchymal stage of the renal gammagraphy immediately after the transplant are variables that affect the survival of the graft.

[Time-influencing factors for biochemical progression following radical prostatectomy]. / Factores influyentes en el tiempo hasta la progresión bioquímica después de prostatectomía radical.

INTRODUCTION: We assessed the time-influencing clinical-pathological factors for biochemical progression of an equal series of patients from a single institution. MATERIALS AND METHODS: Retrospective analysis of 278 patients with biochemical progression following prostatectomy. We considered biochemical progression to be PSA>0.4 ng/ml. We performed the trial using the Cox model (univariate and multivariate) and using the Student's t-test to compare averages. RESULTS: With a mean follow-up of 4 (±3 DE) years, the univariate study showed a mean until progression for the Gleason score 2-6 in the biopsy of 824 days and 543 for the Gleason score 7-10 (p=0.003). For negative surgical margins, the mean was 920 days and 545 for positive margins (p=0.0001). In the case of a Gleason score 2-7 in the specimen, the mean was 806 days and 501 for a Gleason score 8-10 (p=0.001). Lastly, the mean for the cases with Ki-67 negative in the specimen (< 10%) was 649 days and 345 for Ki-67 positive (> 10%) (p=0.003). In the multivariate study, Ki-67 (OR 1.028; IC 95% 1-1.01; p=0.0001) and Gleason score 8-10 (OR 1.62; IC 95% 1.5-2.45; p=0.026) in the specimen, and initial PSA >10 ng/ml (OR 1.02; IC 95% 1.01-1.04; p=0.0001) were independent variables. Using these variables, we designed a predictive model with three groups. The time until the progression of each group was 1,081, 551 and 218 days respectively. CONCLUSION: The Gleason score 7-10 in the prostate biopsy, the presence of Ki-67, the positive margins and the Gleason score 8-10 in the specimen, and the initial PSA > 10 ng/ml are time-influencing factors until biochemical progression. Pathological Gleason score 8-10, PSA > 10 ng/ml and Ki-67 are independent factors.

Site-Dependent Coordination Bonding in Self-Assembled Metal-Organic Networks.

The combination of organic linkers with metal atoms on top of inorganic substrates offers promising perspectives for functional electronic and magnetic nanoscale devices. Typically, coordination bonds between electron-rich end groups and transition-metal atoms lead to the self-assembly of metal-organic nanostructures, whose shape and electronic and magnetic properties crucially depend on the type of ligand. Here, we report on the site-selective bonding properties of Co atoms to the dichotomic dicyanoazobenzene molecule with its carbonitrile and diazo N-based moieties as possible ligands. Using low-temperature scanning tunneling microscopy (STM) and spectroscopy measurements, we resolve the formation of self-assembled metal-organic motifs. Cobalt atoms exhibit a clear spectroscopic fingerprint dependent on the different coordination site, which is further used to map their position, otherwise not clearly visible in the topographic STM images. Density functional theory corroborates the observed bonding patterns and evidences their coordinative nature.

Nondegenerate metallic States on Bi(114): a one-dimensional topological metal.

The (114) surface of the semimetal Bi is found to support a quasi-one-dimensional, metallic surface state. As required by symmetry, the state is degenerate along the Gamma-Y line of the surface Brillouin zone with a highest binding energy of approximately 150 meV. In the Gamma-X direction the degeneracy is lifted by the strong spin-orbit splitting in Bi, as directly shown by spin-resolved photoemission. This results in a Fermi contour consisting of two closely separated, parallel lines of opposite spin direction. It is argued that similar states on related insulators would give rise to a one-dimensional quantum spin Hall effect.

Vibrational Kondo effect in pure organic charge-transfer assemblies.

A Kondo resonance has been observed using a scanning tunneling microscope on a single molecular layer of a purely organic charge-transfer salt grown on a metal surface. Analysis of the Kondo anomaly reveals that the electron acceptor of the film possesses a spin-1/2 ground state due to the localization of an unpaired electron in the conjugated lowest unoccupied molecular orbital. Because of the pi character of this molecular state the unpaired electron is strongly coupled to molecular vibrations, leading to the split of the Kondo resonance in vibrational sidebands.

Resonant electron heating and molecular phonon cooling in single C60 junctions.

We study heating and heat dissipation of a single C(60) molecule in the junction of a scanning tunneling microscope by measuring the electron current required to thermally decompose the fullerene cage. The power for decomposition varies with electron energy and reflects the molecular resonance structure. When the scanning tunneling microscope tip contacts the fullerene the molecule can sustain much larger currents. Transport simulations explain these effects by molecular heating due to resonant electron-phonon coupling and molecular cooling by vibrational decay into the tip upon contact formation.

Formation of dispersive hybrid bands at an organic-metal interface.

An electronic band with quasi-one-dimensional dispersion is found at the interface between a monolayer of a charge-transfer complex (TTF-TCNQ) and a Au(111) surface. Combined local spectroscopy and numerical calculations show that the band results from a complex mixing of metal and molecular states. The molecular layer folds the underlying metal states and mixes with them selectively, through the TTF component, giving rise to anisotropic hybrid bands. Our results suggest that, by tuning the components of such molecular layers, the dimensionality and dispersion of organic-metal interface states can be engineered.

Adsorption of N2O on Cu(100): a combined scanning tunneling microscopy and density functional theory study.

The adsorption of N(2)O on Cu(100) has been studied by using scanning tunneling microscopy (STM). In the first molecular layer N(2)O forms a densely packed c(3 x 2) structure, in which the molecules occupy two different adsorption sites. The bonding strength of this layer is found to be very weak as revealed by a low desorption temperature and the formation of misalignments and defects. Density functional theory (DFT) finds a stable c(3 x 2) structure in which the molecules are considerably bent due to charge transfer. In model calculations for a 2 x 2 hollow phase we show that in order to reach the chemisorbed, bent configuration, the molecules have to pass an activation barrier. In the experimentally accessible range, this is apparently not possible and the molecules remain in a stable physisorbed state.

Reducing the molecule-substrate coupling in C60-based nanostructures by molecular interactions.

Codeposition of C60 and the three-dimensional molecular hydrocarbon 1,3,5,7-tetraphenyladamantane (TPA) on Au(111) leads to the spontaneous formation of molecular nanostructures in which each fullerene is locked into a specific orientation by three surrounding TPA. Scanning tunneling spectroscopy shows that the electronic coupling of C60 with the surface is significantly reduced in these nanostructures, enhancing the free-molecule properties. As evidenced by density functional theory simulations, the nanostructures are stabilized by 18 local electrostatic forces between C60 and TPA, resulting in a lifting of the C60 cage from the surface.