A Group-Theoretic Approach to the Origin of Chirality-Induced Spin-Selectivity in Nonmagnetic Molecular Junctions.

Spin-orbit coupling gives rise to a range of spin-charge interconversion phenomena in nonmagnetic systems where certain spatial symmetries are reduced or absent. Chirality-induced spin-selectivity (CISS), a term that generically refers to a spin-dependent electron transfer in nonmagnetic chiral systems, is one such case, appearing in a variety of seemingly unrelated situations ranging from inorganic materials to molecular devices. In particular, the origin of CISS in molecular junctions is a matter of an intense current debate. Here, we derive a set of geometrical conditions for this effect to appear, hinting at the fundamental role of symmetries beyond otherwise relevant quantitative issues. Our approach, which draws on the use of point-group symmetries within the scattering formalism for transport, shows that electrode symmetries are as important as those of the molecule when it comes to the emergence of a spin-polarization and, by extension, to the possible appearance of CISS. It turns out that standalone metallic nanocontacts can exhibit spin-polarization when relative rotations which reduce the symmetry are introduced. As a corollary, molecular junctions with achiral molecules can also exhibit spin-polarization along the direction of transport, provided that the whole junction is chiral in a specific way. This formalism also allows the prediction of qualitative changes of the spin-polarization upon substitution of a chiral molecule in the junction with its enantiomeric partner. Quantum transport calculations based on density functional theory corroborate all of our predictions and provide further quantitative insight within the single-particle framework.

Unraveling the Interplay between Quantum Transport and Geometrical Conformations in Monocyclic Hydrocarbons' Molecular Junctions.

In the field of molecular electronics, especially in quantum transport experiments, determining the geometrical configurations of a single molecule trapped between two electrodes can be challenging. To address this challenge, we employed a combination of molecular dynamics (MD) simulations and electronic transport calculations based on density functional theory to determine the molecular orientation in our break-junction experiments under ambient conditions. The molecules used in this study are common solvents used in molecular electronics, such as benzene, toluene (aromatic), and cyclohexane (aliphatic). Furthermore, we introduced a novel criterion based on the normal vector of the surface formed by the cavity of these ring-shaped monocyclic hydrocarbon molecules to clearly define the orientation of the molecules with respect to the electrodes. By comparing the results obtained through MD simulations and density functional theory with experimental data, we observed that both are in good agreement. This agreement helps us to uncover the different geometrical configurations that these molecules adopt in break-junction experiments. This approach can significantly improve our understanding of molecular electronics, especially when using more complex cyclic hydrocarbons.

A new methodology to assess the performance of AOPs in complex samples: Application to the degradation of phenolic compounds by O3 and O3/UV-A-Vis.

A methodology combining experimental design methodology, liquid chromatography, excitation emission matrixes (EEM) and bioassays has been applied to study the performance of O3 and O3/UVA-vis in the treatment of a mixture of eight phenolic pollutants. An experimental design methodology based on Doehlert matrixes was employed to determine the effect of pH (between 3 and 12), ozone dosage (02-1.0 g/h) and initial concentration of the pollutants (1-6 mg/L each). The following conclusions were obtained: a) acidic pH and low O3 dosage resulted in an inefficient process, b) increasing pH and O3 amount produced an enhancement of the reaction, and c) interaction of basic pH and high amounts of ozone decreased the efficiency of the process. The combination of O3/UVA-vis was able to enhance ozonation in those experimental regions were this reagent was less efficient, namely low pH and low ozone dosages. The application of EEM-PARAFAC showed four components, corresponding to the parent pollutants and three different groups of reaction product and its evolution with time. Bioassys indicated important detoxification (from 100% to less than 30% after 1 min of treatment with initial pollutant concentration of 6 mg/L, pH = 9 and ozone dosage of 0.8 g/h) according to the studied methods (D. magna and P. subcapitata). Also estrogenic activity and dioxin-like behavior were significantly decreased.

Impact of a shift work-like lighting schedule on the functioning of the circadian system in the short-lived fish Nothobranchius furzeri.

Adult Nothobranchius furzeri of the MZM-04/10 strain were individually kept and subjected to a "5 + 2" shifting lighting schedule (SHIFT) for 8 weeks in order to evaluate the desynchronizing effects of a simulated human-like shift-work schedule on the functioning of the circadian system (CS). With this aim, sixteen 21-week-old N. furzeri were placed into a Morning, Night and Evening schedule (lights on from 08:00 to 16:00, 00:00 to 08:00 and 16:00 to 00:00 h, respectively) and fed once a day in the middle of the corresponding photophase (12:00, 04:00 and 20:00 h, respectively). Then, in the weekends (2 days), fish were always returned to the Morning shift. As controls, 16 fish were maintained under a non-shifting LD cycle condition (CONTROL) throughout the whole experiment, with lights on from 08:00 to 16:00 h. Rest-activity rhythm (RAR) of fish subjected to SHIFT showed several symptoms of chronodisruption, such as a decrease in the percentage of diurnal activity and a reduction of the relative amplitude and the circadian function index with time. When a periodogram analysis was performed, RAR of N. furzeri under SHIFT conditions showed up to three separate circadian components: one longer than 24 h (26.5 h) that followed the weekly 8 h delays; a short-period component (~23 h) that was related to the weekend's phase advances, and finally, a 24 h component. The shifting LD schedule also affected fish CS at a molecular level, with several significant differences in the expression of core genes of the molecular clock (bmal1, clock, rorα, rev-erbα) between SHIFT and CONTROL animals. RAR impairment along with changes in clock gene expression could be associated with high stress and accelerated aging in these fish.

Influence of Relativistic Effects on the Contact Formation of Transition Metals.

Our analysis of the contact formation processes undergone by Au, Ag, and Cu nanojunctions reveals that the distance at which the two closest atoms on a pair of opposing electrodes jump into contact is, on average, 2 times longer for Au than either Ag or Cu. This suggests the existence of a longer-range interaction between those two atoms in the case of Au, a result of the significant relativistic energy contributions to the electronic structure of this metal, as confirmed by ab initio calculations. Once in the contact regime, the differences between Au, Ag, and Cu are subtle, and the conductance of single-atom contacts for metals of similar chemical valence is mostly determined by geometry and coordination.

Seudoaneurisma micótico de aorta abdominal a causa de una espondilodiscitis por Escherichia coli / Mycotic abdominal aortic pseudoaneurysm due to spondylodiscitis caused by Escherichia coli

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Topologically protected quantum transport in locally exfoliated bismuth at room temperature.

We report electrical conductance measurements of Bi nanocontacts created by repeated tip-surface indentation using a scanning tunneling microscope at temperatures of 4 and 300 K. As a function of the elongation of the nanocontact, we measure robust, tens of nanometers long plateaus of conductance G0 = 2e2/h at room temperature. This observation can be accounted for by the mechanical exfoliation of a Bi(111) bilayer, a predicted quantum spin Hall (QSH) insulator, in the retracing process following a tip-surface contact. The formation of the bilayer is further supported by the additional observation of conductance steps below G0 before breakup at both temperatures. Our finding provides the first experimental evidence of the possibility of mechanical exfoliation of Bi bilayers, the existence of the QSH phase in a two-dimensional crystal, and, most importantly, the observation of the QSH phase at room temperature.

Mechanical annealing of metallic electrodes at the atomic scale.

The process of creating an atomically defined and robust metallic tip is described and quantified using measurements of contact conductance between gold electrodes and numerical simulations. Our experiments show how the same conductance behavior can be obtained for hundreds of cycles of formation and rupture of the nanocontact by limiting the indentation depth between the two electrodes up to a conductance value of approximately 5G0 in the case of gold. This phenomenon is rationalized using molecular dynamics simulations together with density functional theory transport calculations which show how, after repeated indentations (mechanical annealing), the two metallic electrodes are shaped into tips of reproducible structure. These results provide a crucial insight into fundamental aspects relevant to nanotribology or scanning probe microscopies.

Effect of glyphosate on growth of four freshwater species of phytoplankton: a microplate bioassay.

The acute toxicity of glyphosate herbicide was tested on the four species of freshwater phytoplankton, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila. Herbicide concentrations eliciting a 50% growth reduction over 72 h (EC(50)) ranged from 24.5 to 41.7 mg L(-1), whilst a 10% growth inhibition is achieved by herbicide concentrations ranging from 1.6 to 3.0 mg L(-1), difficult to find neither in paddy fields (it is not used in rice) nor in the lake of the Albufera Natural Park. Chorella species are less sensitive to the herbicide than Scenedesmus species. It can be concluded that glyphosate has a low potential risk for the tested organisms.

Eficacia a largo plazo de una intervención para la deshabituación del consumo crónico de benzodiazepinas / Long-term effectiveness of an intervention to discontinue chronic benzodiazepine use

Introducción. Se evalúa la efectividad a largo plazo de una intervención para la deshabituación del consumo crónico de benzodiazepinas. Métodos. Diseño: seguimiento posterior al cierre de un ensayo clínico aleatorizado. Ámbito: tres centros de salud que cubren una población de 82.000 habitantes. Sujetos: 135 pacientes finalizaron el ensayo clínico previo (66 del grupo intervención, 63 del grupo control y 6 habían fallecido). Intervención-mediciones: el ensayo clínico previo comparó la eficacia de una intervención basada en una entrevista estructurada y reducción gradual de dosis frente a un grupo control con seguimiento clínico habitual. Los resultados fueron evaluados a los 12 meses. La variable principal es consumo o no de benzodiazepinas 3 años tras finalizar el estudio, principio activo y motivo de consumo. Resultados. Tras 3 años de seguimiento, 25/66 del grupo de intervención y 14/63 del grupo control no consumen benzodiazepinas. La probabilidad de abandonar el consumo de benzodiazepinas entre los pacientes que recibieron intervención era un 41% más elevada que en el grupo control. Riesgo relativo: 1,41 (intervalo de confianza del 95%: 0,98-1,66). En el grupo intervención, 16 de los 31 (51,6%) que abandonaron el consumo a los 12 meses siguen sin consumir. La benzodiazepina más prescrita es lorazepam (27,9%)seguida de alprazolam (12,4%), y el principal motivo de prescripción es ansiedad (16,3 %) seguido de trastorno mixto ansiosodepresivo (10,9%).Conclusiones. A pesar de la importante tasa de recaída, la intervención para reducir el consumo crónico de benzodiacepinas mantiene su eficacia a largo plazo (AU)

Introduction. We establish the long-term effectiveness of a brief intervention to withdraw from chronic benzodiazepine use. Methods. Follow-up after a randomized clinical trial. Setting: Three health care centers covering 82,000 inhabitants. Subjects: 135 patients who completed the previous clinical trial (66 from the intervention group,63 from the control group, 6 had died). Intervention measurements: the previous clinical trial compared an intervention consisting of standardized advice and a dose tapering schedule against a control group followed by usual care. Results were evaluated at 12 months. Main outcome: benzodiazepine use three years after the end of the clinical trial, type of drug and the reason for prescription. Results. After 3 years of follow up, 25/66 (37.9%) subjects from the intervention group and 14/63 (22.2%) from the control group were benzodiazepine free. The probability of withdrawal from benzodiazepine between patients in the intervention group was 41% higher than in the control group. Relative risk: 1.41 (95% confidence interval:0.98-1.66). In the intervention group, 16 from 31 (51.6%) patients who had withdrawn at 12 months were benzodiazepine free after 3 years. The most prescribed benzodiazepine is lorazepam (27.9%), followed by alprazolam (12.4 %) and the main reason for prescription is anxiety (16.3%) followed by anxious-depressive disorder (10.9%).Conclusions. Even though there is a substantial relapse rate, the intervention to reduce chronic benzodiazepine use remains effective in the long-term (AU)

[Long-term effectiveness of an intervention to discontinue chronic benzodiazepine use]. / Eficacia a largo plazo de una intervención para la deshabituación del consumo crónico de benzodiazepinas.

INTRODUCTION: We establish the long-term effectiveness of a brief intervention to withdraw from chronic benzodiazepine use. METHODS: Follow-up after a randomized clinical trial. SETTING: Three health care centers covering 82,000 inhabitants. SUBJECTS: 135 patients who completed the previous clinical trial (66 from the intervention group, 63 from the control group, 6 had died). Intervention-measurements: the previous clinical trial compared an intervention consisting of standardized advice and a dose tapering schedule against a control group followed by usual care. Results were evaluated at 12 months. main outcome: benzodiazepine use three years after the end of the clinical trial, type of drug and the reason for prescription. RESULTS: After 3 years of follow up, 25/66 (37.9%) subjects from the intervention group and 14/63 (22.2%) from the control group were benzodiazepine free. The probability of withdrawal from benzodiazepine between patients in the intervention group was 41% higher than in the control group. Relative risk: 1.41 (95% confidence interval: 0.98-1.66). In the intervention group, 16 from 31 (51.6%) patients who had withdrawn at 12 months were benzodiazepine free after 3 years. The most prescribed benzodiazepine is lorazepam (27.9%), followed by alprazolam (12.4%) and the main reason for prescription is anxiety (16.3%) followed by anxious-depressive disorder (10.9%). CONCLUSIONS: Even though there is a substantial relapse rate, the intervention to reduce chronic benzodiazepine use remains effective in the long-term.

Effects of propanil, tebufenozide and mefenacet on growth of four freshwater species of phytoplankton: a microplate bioassay.

The Albufera Natural Park situated in Valencia (Spain), with a very rich flora and fauna is surrounded by rice fields in which pesticide spraying is a regular practice. With this in mind, the sensitivity of four algal species, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila to pesticides propanil, tebufenozide and mefenacet was studied using single species toxicity tests. Organisms were exposed to different concentrations of these herbicides and the algal growth was measured in a microplate reader at 410 nm, at 0, 24, 48 and 72 h. Tebufenozide appeared to be the most inhibitory to Scenedesmus and Chlorella species growth. 72 h EC50 of propanil, tebufenozide and mefenacet ranged from 0.29 to 5.98 mg/l, 0.12 to 0.15 mg/l and from 0.25 to 0.67 mg/l, respectively for the four algal species. The two species of Chlorella were more tolerant than the two species of Scenedesmus.

Effects of metabolic control on vitamin E nutritional status in children with type 1 diabetes mellitus.

OBJECTIVE: To evaluate the effects of the metabolic control of the insulin-dependent diabetes mellitus (IDDM) on the nutritional status of vitamin E. METHODS: A total of 47 children with IDDM and a mean age of 11.91+/-1.60 (mean+/-SD) years were studied, matched for age and sex with 16 healthy children (11.75+/-1.83 years). Following the American and British Associations for IDDM, we used a classification of "good", "moderate" or "poor" control of the illness: (a) good control [glycosilated haemoglobin (HbAlc) < or =7%]; (b) moderate control (7%< HbAlc < or =8%); and (c) poor control (HbAlc>8%). Serum concentrations of total cholesterol (CHOL), triglycerides (TG), high-density lipoproteins-cholesterol (HDLc), very low- and low-density lipoproteins cholesterol (VLDLc and LDLc), plasma and erythrocyte vitamin E (Vit Ep and Vit Ee) and plasma vitamin A (Vit Ap) were measured in all children. RESULTS: The children with "poor" metabolic control of the illness presented significantly higher plasma concentrations of CHOL, LDLc, VLDLc, LDLc/HDLc, (VLDL+LDL)c/HDLc, TG and Vit Ep; higher indices Vit Ep/Vit Ee and Vit Ep/Vit Ap relative to those with a "good" control of the illness. Direct-linear correlations were found between Vit Ep and the percentage of HbAlc and with the markers of atherogenic risk in the IDDM children. CONCLUSION: There is a significant rise in Vit Ep concentrations as metabolic control of the illness worsens, whereas Vit Ee remained unchanged. These results suggest that vitamin E maintains its nutritional status despite a poor control of the IDDM during childhood.

Tratamiento combinado abierto y endovascular de aneurismas anastomóticos postinjerto bifurcado aortobifemoral / Combined open and endovascular treatment of aortobifemoral bifurcated post-graft anastomotic aneurysms

Introducción. El aneurisma anastomótico está sujeto a las mismas complicaciones que un aneurisma verdadero, y su tratamiento, tanto electivo como de urgencia, presenta cifras de morbimortalidad muy elevadas. Describimos un caso en que se utiliza la técnica combinada, cirugía abierta y endovascular, para el tratamiento de la complicación aneurismática de un injerto aortobifemoral.Caso clínico. Las lesiones se identifican en un varón de 70 años, 11 años después de la realización de una derivación aortobifemoral por una enfermedad isquémica aortoilíaca. Se identifica un pseudoaneurisma femoral derecho mediante palpación y ecografía Doppler. En el estudio preoperatorio se realiza una tomografía computarizada (TC) abdominopélvica que describe un pseudoaneurisma anastomótico aórtico. Se trata la lesión femoral por cirugía convencional, derivación corta de PTFE de 8 mm desde la rama derecha del bifurcado hasta la arteria femoral profunda. Debido a un alto riesgo quirúrgico (ASA IV) y a un abdomen hostil, bajo anestesia intradural se realiza la exclusión del pseudoaneurisma aórtico por medio de la implantación de una endoprótesis recta. Tras la liberación de la prótesis se verifica una fuga distal de contraste, que se corrige mediante la colocación de una extensión de prótesis recta cubierta. El control arteriográfico inmediato no evidencia ningún flujo de contraste en el interior del saco aneurismático. No hay complicaciones postoperatorias y el enfermo se mantiene asintomático.La TC de control a los seis meses confirma la exclusión completa del pseudoaneurisma. Conclusión. En un caso seleccionado, en que la cirugía abierta represente un riesgo elevado, es factible el tratamiento endovascular de los pseudoaneurismas anastomóticos aórticos no infectados. [ (AU)

Tratamiento fibrinolítico y quirúrgico de la trombosis aguda de la carótida interna. A propósito de un caso / Fibrinolytic and surgical treatment of acute thrombosis of the internal carotid artery. A case report

Introducción. El tratamiento de la trombosis aguda de la carótida interna ha obtenido clásicamente malos resultados. Presentamos un caso en el que se practicó un tratamiento fibrinolítico previo y posteriormente quirúrgico, y realizamos una revisión de la bibliografía. Caso clínico. Paciente de 65 años que refiere una historia de varios episodios de parestesias en extremidades izquierdas los últimos dos días. En las últimas cuatro horas presenta un déficit neurológico progresivo en dichas extremidades. Como antecedentes destaca un infarto cerebral isquémico silviano derecho, cuatro años antes, con mínima secuela. La TAC craneal no revela signos de hemorragia. Se inicia tratamiento descoagulante con heparina sódica, a pesar de lo cual persiste la clínica. La arteriografía de urgencia revela estenosis preoclusiva de carótida interna derecha con trombosis aguda de la misma. Se practica fibrinólisis local con activador tisular del plasminógeno recombinante (r-TPA), y se inicia la recuperación del déficit inmediatamente. A las 18 h se realiza endarterectomía carotídea sin complicaciones. A los 18 meses, el paciente presenta un ligero déficit residual en forma de torpeza de la mano -que ya presentaba antes de la trombosis-. Discusión. En casos de trombosis aguda de carótida interna, un tratamiento fibrinolítico administrado precozmente puede ayudar a mejorar los resultados del tratamiento quirúrgico. Todavía faltan estudios para evaluar la eficacia de la fibrinólisis intrarterial local, que podría presentar menos complicaciones hemorrágicas que la fibrinólisis sistémica (AU)

Effects of bensulfuron-methyl and cinosulfuron on growth of four freshwater species of phytoplankton.

The acute toxicity of sulfonylurea herbicides bensulfuron-methyl and cinosulfuron was tested on the five species of freshwater phytoplankton: Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris and Chlorella saccharophila. Herbicide concentrations eliciting a 50% growth reduction over 96 h (EC50) ranged from 8 to 104 mg/l for cinosulfuron and from 0.015 to 6.2 mg/l for bensulfuron-methyl. The pesticides bensulfuron-methyl, atrazine and benthiocarb were more toxic than cinosulfuron, chlorsulfuron, molinate, fenitrothion and pyridaphenthion in a toxicity study with the same algal species. The transformation of effective concentrations of bensulfuron-methyl and cinosulfuron and other pesticides, obtained from toxicity measurements, into percent of the saturation level in water is used as a first evaluation of potential hazard to aquatic systems. The herbicides cinosulfuron, methyl-bensulfuron, atrazine and chlorsulfuron were more dangerous than the herbicides benthiocarb and molinate and than the insecticides fenitrothion and pyridaphenthion, in a study of hazard evaluation. The two species of Chlorella were more tolerant to both herbicides than the two species of Scenedesmus. A potential environmental hazard of sulfonylurea herbicides to aquatic systems has to be expected even at low environmental concentrations.

Tumoración ovárica gigante de crecimiento retroperitoneal / Giant ovarian tumour, growing retroperitonealy

Se expone el caso clínico de una muchacha de 14 años que presenta una tumoración abdominal gigante, de evolución asintomática, que resultó ser un cistoadenoma seroso de ovario pero de crecimiento retroperitoneal. Se plantea como causa de esta anomalía anatómica el antecedente quirúrgico en la infancia de la corrección de una enfermedad de Hirschprung (AU)

Effects of pyridaphenthion on growth of five freshwater species of phytoplankton. A laboratory study.

The acute toxicity of the insecticide and acaricide pyridaphenthion to five species of freshwater phytoplankton, Scenedesmus acutus, Scenedesmus subspicatus, Chlorella vulgaris, Chlorella saccharophila and Pseudanabaena galeata was determined. Insecticide concentrations eliciting a 50% growth reduction over 96 h (EC50) ranged from 2.2 to 30.9 mg/l. The two species of Chlorella and the cyanobacteria P. galeata were more tolerant than the two species of Scenedesmus. Concentrations of pyridaphenthion detected in some natural waters were less than the toxic threshold for these species.

Effects of the organophosphorus insecticide fenitrothion on growth in five freshwater species of phytoplankton.

The acute toxicity of the insecticide fenitrothion was measured using four freshwater algae (Chlorella saccharophila, Chlorella vulgaris, Scenedesmus acutus, and Scenedesmus subspicatus) and one cyanobacteria (Pseudanabaena galeata). Insecticide concentrations eliciting 50% growth reduction over 96 hr (EC50) ranged from 0.84 to 11.9 mg/L. Fenitrothion was more toxic than other pesticides studied with the same algal species such as chlorsulfuron, molinate, and pyridaphenthion. The transformation of effective concentrations of fenitrothion and other pesticides obtained from toxicity measurements into percent of the saturation level in water is used as a first evaluation of potential hazard to aquatic systems. The insecticides fenitrothion and pyridaphenthion were less hazardous than the herbicides atrazine, benthiocarb, cinosulfuron, chlorsulfuron, methyl-bensulfuron, and molinate. The two species of Chlorella and the cyanobacterium Pseudanabaena were more tolerant to fenitrothion than the two species of Scenedesmus.

Bioconcentration of the insecticide pyridaphenthion by the green algae Chlorella saccharophila.

A study was undertaken to examine the uptake of the organophosphate insecticide pyridaphenthion in the chlorophyta Chlorella saccharophila. Algae cultures were exposed to the initial nominal concentration 10.0 mg l(-1) pyridaphention during seven days. The insecticide bioconcentrates in the biomass to the highest level of 441.5 +/- 25.9 mg kg(-1) on the fifth day of exposure and was followed by a decrease to 76.6 +/- 5.1 mg kg(-1) on the seventh day. A model was constructed to describe the dynamic process, which estimated a bioconcentration factor (BCF) equal to 28. The study demonstrates the potential of accumulation of pyridaphenthion in aquatic organisms and helps to expand the pyridaphenthion toxicity database. The replacement of fenitrothion by pyridaphenthion concerning their use in rice flooded cultures is discussed.