Twist, tilt, and orientational order at the nematic to twist-bend nematic phase transition of 1″,9″-bis(4-cyanobiphenyl-4′-yl) nonane: A dielectric, 2H NMR, and calorimetric study

Under the terms of the Creative Commons Attribution license.-- et al.The nature of the nematic-nematic phase transition in the liquid crystal dimer 1″,9″-bis(4-cyanobiphenyl-4′-yl) nonane (CB9CB) has been investigated using techniques of calorimetry, dynamic dielectric response measurements, and H2 NMR spectroscopy. The experimental results for CB9CB show that, like the shorter homologue CB7CB, the studied material exhibits a normal nematic phase, which on cooling undergoes a transition to the twist-bend nematic phase (NTB), a uniaxial nematic phase, promoted by the average bent molecular shape, in which the director tilts and precesses describing a conical helix. Modulated differential scanning calorimetry has been used to analyze the nature of the NTB-N phase transition, which is found to be weakly first order, but close to tricritical. Additionally broadband dielectric spectroscopy and H2 magnetic resonance studies have revealed information on the structural characteristics of the recently discovered twist-bend nematic phase. Analysis of the dynamic dielectric response in both nematic phases has provided an estimate of the conical angle of the heliconical structure for the NTB phase. Capacitance measurements of the electric-field realignment of the director in initially planar aligned cells have yielded values for the splay and bend elastic constants in the high temperature nematic phase. The bend elastic constant is small and decreases with decreasing temperature as the twist-bend phase is approached. This behavior is expected theoretically and has been observed in materials that form the twist-bend nematic phase. H2 NMR measurements characterize the chiral helical twist identified in the twist-bend nematic phase and also allow the determination of the temperature dependence of the conical angle and the orientational order parameter with respect to the director.The authors are grateful for financial support from the MICINN project MAT2012-38538-C03-02,03 and from the Eusko Jaurlaritza-Gobierno Vasco (GI/IT-449-10). The authors also acknowledge the recognition from the Generalitat de Catalunya of GRPFM as Emergent Research Group (2009-SGR-1243). N.S. thanks the Alexander von Humboldt Foundation for a Postdoctoral Research Fellowship.Peer Reviewe

Influencia de la administración de psicofármacos en el aumento del peso corporal

Obesity has become a major public health burden, not only by the rising prevalence but also because of the associated complications. Furthermore there is a number of diseases whose risk and onset is increased in subjects with overweight such as type 2 diabetes, dislipemias, tumors (endometrial, colon, breast, cancer, etc), skeletal disorders, digestive disturbances, cardiovascular diseases, respiratory disorders, psychological problems, obstetric and gynecological disorders.The prescription of psychotropic drugs is important and, in most countries, consumption has been increased in recent years. Indeed, several drugs used in the treatment of anxiety, depression, bipolar disorder, schizophrenia or epilepsy, can increase body weight and fat deposition or eventually decrease it. These side effects could make a previous situation of obesity to worsen, and it can even cause excessive weight gain in patients with a normal weight at the beginning of the treatment. This increase in adiposity may also contribute to the lack of adherence to the medication and thus a possible relapse of the patients.In this review we report the links between psychotropic drugs administration and weight gain as well as the potential mechanisms that are involved.DOI: http://dx.doi.org/10.14306/renhyd.17.1.4La obesidad se ha convertido en un importante problema de salud pública, no sólo por su creciente prevalencia sino por las patologías asociadas. En efecto, hay un gran número de enfermedades cuyo riesgo de padecerlas se ve aumentado en aquellos sujetos que presentan exceso de peso: Diabetes Mellitus tipo 2, dislipemias, tumores (endometrio, colon, mama, etc), trastornos del aparato locomotor, alteraciones digestivas, enfermedades cardiovasculares, alteraciones respiratorias, problemas psicológicos, alteraciones obstétricas y ginecológicas.En España, el consumo de psicofármacos es importante y en los últimos años se ha incrementado. Muchos de los medicamentos utilizados en el tratamiento de la ansiedad, la depresión, el trastorno bipolar, la esquizofrenia, la epilepsia, pueden producir un aumento o disminución de peso. Estos efectos secundarios podrían agravar una situación previa de obesidad e incluso provocar una ganancia ponderal en pacientes que al comenzar el tratamiento presentan peso normal, con el riesgo y complicaciones asociadas. Esta acumulación de grasa inducida puede contribuir también a la falta de adherencia a la medicación y, por tanto, a posibles recaídas de estos enfermos.En esta revisión se trata de precisar la relación entre psicofármacos y obesidad, así como los mecanismos potencialmente implicados

Estudio comparativo de medidas de composición corporal por absorciometría dual de rayos X, bioimpedancia y pliegues cutáneos en mujeres

Body composition assessments are important important measurements for the diagnosis and monitoring of obesity. The present study compared the body mass index (IMC) with body fat content estimated by skinfold (PT), bioelectric impedance (BIA) and dual X-ray absorptiometry (DEXA) in adult women (n = 91). Although body fat estimations between methods differed, correlation between the various body composition methods was positive and statistically significant (IMC-BIA, DEXA, PT: 0.902, 0.780, 0.722, respectively; BIA-DEXA, PT: 0.794 y 0.674 respectively; DEXA-PT: 0.787, all correlations p < 0.001). In relation to concordance indexes between measurements to classify individuals in normo- or overweight, it was globally low, with the exception of the concordance between body mass index with bioimpedance, which was good, and body mass index with triceps skinfold, which was acceptable. In conclusion, the outcomes obtained in the present study suggest that body fat content estimation can be very different depending on the method employed but the good correlation existing between methods permits to compare body fat content evolution during a dietary intervention, if the analysis is always performed by the same method in the same individual.Las medidas de composición corporal son herramientas normalmente empleadas para el diagnóstico y seguimiento de la obesidad. En el presente trabajo se estudiaron las diferencias entre el índice de masa corporal (IMC), contenido de grasa medido por pliegues cutáneos (PT), impedancia bioeléctrica (BIA) y absorciometría dual de rayos-X (DEXA), como métodos de medida de composición corporal, en mujeres adultas (n = 91). Aunque la estimación de grasa corporal entre los métodos fue diferente, la correlación entre las medidas de composición corporal fue positiva (IMC-BIA, DEXA, PT: 0.902, 0.780, 0.722, respectivamente; BIA-DEXA, PT: 0.794 y 0.674 respectivamente; DEXA-PT: 0.787, todas las correlaciones p < 0.001) y estadísticamente significativa. En cuanto a la concordancia entre métodos para clasificar individuos en normopeso o sobrepeso, fue en general baja, excepto en el caso del índice de masa corporal con la bioimpedancia, que fue buena, y el índice de masa corporal con la medida del pliegue tricipital, que fue aceptable. En conclusión, los resultados de este estudio apuntan a que la medida del contenido de grasa puede ser diferente en función del método de estimación empleado, pero la buena correlación entre ellos permite comparar la evolución del contenido de grasa durante una intervención dietética, siempre y cuando se tome como referencia el mismo aparato para un mismo individuo

DNMR measurements of an asymmetric odd liquid crystal dimer: determination of the intramolecular angle and the degree of order of the two rigid cores

In this work, we present a Deuteron Nuclear Magnetic Resonance (DNMR) study of the non-symmetric odd liquid crystal dimer α-(4-cyanobiphenyl-4′-yloxy)-ω-(1-pyrenimine-benzylidene-4′-oxy) heptane (CBO7O.Py), formed by a pro-mesogenic cyanobiphenyl unit and a bulky pyrene-containing unit, linked via alkoxy flexible chain. We have synthesized two partially deuterated samples: one with the deuterium atoms in the cyanobiphenyl moiety (dCBO7O.Py) and the other one with the deuterium atoms in the pyrenimine-benzylidene unit (CBO7O.dPy). We have performed angular distribution analysis in the SmA glassy state, obtaining the degree of order of both rigid cores and an estimation of the internal molecular angle between both structures. With the results from the angular study, we have been able to determine the degree of order of both rigid units in either the N phase and the SmA phase, far enough from the glass transition. Both rigid cores have the same degree of order close to the nematic–isotropic phase transition, but as the compound is cooled down, the degree of order of the cyanobiphenyl moiety is clearly higher than that of the pyrene-containing unit. The critical behaviour of the order parameter of the pyrene-containing moiety is consistent with the fact that, for CBO7O.Py, the N–I phase transition is tricritical, which seems to indicate that the uniaxial order parameter of the dimer is dominated by the degree of order of the pyrene-containing core.The authors from INMA greatly appreciate financial support from projects of the Spanish Government PDI2021-122882NB-I0 [MCIU/AEI/FEDER, UE] and the Gobierno de Aragón/FEDER (research group E47_20R). Thanks to the nuclear magnetic resonance, mass spectrometry, elemental and thermal analysis services of the CEQMA (Univ. Zaragoza-CSIC). The authors from UPV-EHU are grateful to Gobierno Vasco for funding (IT1458-22). N. S. acknowledges the financial support from the Slovenian Research Agency (research core funding No. P1-0192).Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Two glass transitions associated to different dynamic disorders in the nematic glassy state of a non-symmetric liquid crystal dimer dopped with γ-alumina nanoparticles

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license.-- et al.In the present work, the nematic glassy state of the non-symmetric LC dimer α-(4-cyanobiphenyl-4'-yloxy)-ω-(1-pyrenimine-benzylidene-4'-oxy) undecane is studied by means of calorimetric and dielectric measurements. The most striking result of the work is the presence of two different glass transition temperatures: one due to the freezing of the flip-flop motions of the bulkier unit of the dimer and the other, at a lower temperature, related to the freezing of the flip-flop and precessional motions of the cyanobiphenyl unit. This result shows the fact that glass transition is the consequence of the freezing of one or more coupled dynamic disorders and not of the disordered phase itself. In order to avoid crystallization when the bulk sample is cooled down, the LC dimer has been confined via the dispersion of γ-alumina nanoparticles, in several concentrations.The authors are grateful for financial support from the MICINN project MAT2012-38538-C01-02 and 03, the Gobierno Vasco (GI/IT-449-10), the Aragón Government and FSE (Project E04) and the Generalitat de Catalunya, Agència de Gestió d'Ajuts Universitaris i de Recerca (2009SGR1168).We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe

Bone morphogenetic protein-2/4 signalling pathway components are expressed in the human thymus and inhibit early T-cell development

T-cell differentiation is driven by a complex network of signals mainly derived from the thymic epithelium. In this study we demonstrate in the human thymus that cortical epithelial cells produce bone morphogenetic protein 2 (BMP2) and BMP4 and that both thymocytes and thymic epithelium express all the molecular machinery required for a response to these proteins. BMP receptors, BMPRIA and BMPRII, are mainly expressed by cortical thymocytes while BMPRIB is expressed in the majority of the human thymocytes. Some thymic epithelial cells from cortical and medullary areas express BMP receptors, being also cell targets for in vivo BMP2/4 signalling. The treatment with BMP4 of chimeric human–mouse fetal thymic organ cultures seeded with CD34+ human thymic progenitors results in reduced cell recovery and inhibition of the differentiation of human thymocytes from CD4− CD8− to CD4+ CD8+ cell stages. These results support a role for BMP2/4 signalling in human T-cell differentiation

Prognostic Role of TAPSE to PASP Ratio in Patients Undergoing MitraClip Procedure.

Transcatheter mitral valve repair (TMVR) is an effective therapy for high-risk patients with severe mitral regurgitation (MR) but heart failure (HF) readmissions and death remain substantial on mid-term follow-up. Recently, right ventricular (RV) to pulmonary arterial (PA) coupling has emerged as a relevant prognostic predictor in HF. In this study, we aimed to assess the prognostic value of tricuspid annular plane systolic excursion (TAPSE) to PA systolic pressure (PASP) ratio as a non-invasive measure of RV-to-PA coupling in patients undergoing TMVR with MitraClip (Abbott, CA, USA). Multicentre registry including 228 consecutive patients that underwent successful TMVR with MitraClip. The sample was divided in two groups according to TAPSE/PASP median value: 0.35. The primary combined endpoint encompassed HF readmissions and all-cause mortality. Mean age was 72.5 ± 11.5 years and 154 (67.5%) patients were male. HF readmissions and all-cause mortality were more frequent in patients with TAPSE/PASP ≤ 0.35: Log-Rank 8.844, p = 0.003. On Cox regression, TAPSE/PASP emerged as a prognostic predictor of the primary combined endpoint, together with STS-Score. TAPSE/PASP was a better prognostic predictor than either TAPSE or PASP separately. TAPSE/PASP ratio appears as a novel prognostic predictor in patients undergoing MitraClip implantation that might improve risk stratification and candidate selection