Large quantum nonlinear dynamic susceptibility of single-molecule magnets

The nonlinear dynamical response of Mn$_{12}$ single-molecule magnets is experimentally found to be very large, quite insensitive to the spin-lattice coupling constant, and displaying peaks reversed with respect to classical superparamagnets. It is shown that these features are caused by the strong field dependence of the relaxation rate due to the detuning of energy levels between which tunneling takes place. The nonlinear susceptibility technique, previously overlooked, is thus proposed as a privileged probe to ascertain the occurrence of quantum effects in mesoscopic magnetic systems.Comment: 4 pages, 4 figure

Nonlinear response of single-molecule nanomagnets: equilibrium and dynamical

We present an experimental study of the {\em nonlinear} susceptibility of Mn$_{12}$ single-molecule magnets. We investigate both their thermal-equilibrium and dynamical nonlinear responses. The equilibrium results show the sensitivity of the nonlinear susceptibility to the magnetic anisotropy, which is nearly absent in the linear response for axes distributed at random. The nonlinear dynamic response of Mn$_{12}$ was recently found to be very large and displaying peaks reversed with respect to classical superparamagnets [F. Luis {\em et al.}, Phys. Rev. Lett. {\bf 92}, 107201 (2004)]. Here we corroborate the proposed explanation -- strong field dependence of the relaxation rate due to the detuning of tunnel energy levels. This is done by studying the orientational dependence of the nonlinear susceptibility, which permits to isolate the quantum detuning contribution. Besides, from the analysis of the longitudinal and transverse contributions we estimate a bound for the decoherence time due to the coupling to the phonon bath.Comment: 13 pages, 8 figures, resubmitted to Phys. Rev. B with minor change

Advances in aquatic and subterranean beetles research: a tribute to Ignacio Ribera

It has been a bit longer than two years since our friend and colleague Ignacio (Nacho) Ribera passed away. The memory of him remains among those of us who were lucky enough to meet Nacho. This monograph is dedicated to him, bringing a set of scientific contributions from his colleagues whose topics are part of the main research lines (and passions) of his scientific work: taxonomy, systematics, biogeography and evolution of aquatic and subterranean beetles. In the last two years, several contributions have highlighted Nacho’ scientific and personal profile, including the complete list of his publications, and both the taxa described by and dedicated to him (BELLÉS, 2020; CEHRE, 2020; DELOCADO et al., 2020; FAILLE et al., 2020, 2021; JÄCH, 2020; MELIC, 2020; MILLÁN et al., 2020a, b; VALLADARES & MILLÁN, 2020). Nacho was a passionate biologist, interested in everything concerning beetles, especially their diversity, distributions, adaptations and evolution of aquatic and cave beetles. He published a total of 285 papers, in which he described 107 species new to science, highlighting the discovery of the Aspyditidae family. Besides, 7 species and subspecies, and one new genus have been dedicated to him in this monograph, extending to a total of 15 species and two genera. Concerning the aquatic beetles, we would like to emphasise his crucial contributions, such as the first complete checklist of aquatic and semi-aquatic beetles of the Iberian Peninsula. He was a pioneer in studying the adaptive morphology of the family Dytiscidae, and more importantly, he deepens in the phylogeny of the aquatic beetles, shedding light on the systematics and evolution of the families Dytiscidae and Hydraenidae. He postulated the “Habitat Constraint” hypothesis which, from an evolutionary point of view, highlights the importance of habitat stability as a determinant of species range sizes (via differences in their dispersal capabilities). He also dealt in-depth with evolutionary studies related to the habitat transition between lotic and lentic water bodies, but also the transition from freshwater to saline water, or vice versa. Certainly, Nacho, due to his work and publications on aquatic beetles, became one of the most prestigious specialists worldwide. Regarding the subterranean environment, Nacho revealed that Dalyat Mateu is a vicariant genus of carabid whose origin must be in the separation of the Iberian plate from the rest of Pangea in the Jurassic-Cretaceous boundary. He also addressed the position of Ildobates neboti Español, confirming it within the Zuphiini tribe. At the same time, he began to study the phylogeny of the hypogeal Trechini of the Pyrenees, and afterwards he addressed the diversification of Troglocharinus Reitter, opening the way to a new perspective on the evolution and dispersion of the subterranean fauna. He published the first morphological phylogeny through cladistic analysis of the Leptodirini tribe (Leiodidae), and the first molecular phylogenies for the two main groups that have colonised the subterranean environment, the tribes Leptodirini and Trechini. His contribution to the knowledge of underground and stygobic environments between 2005 and 2021, postulated him as one of the most important specialists worldwide also in this field. The complete list of scientific works signed by Nacho, the taxa described by him and those dedicated to his person can be found on the web: https://www.um.es/ecoaqua/index.php/external-collaborators. We do not want to extend further. We hope these pages serve as a tribute to his person, but also a tribute to a life and scientific style that would serve as an example for future generations of insect lovers. Our gratitude to the authors and reviewers of the articles that make up this monograph, as well as to the Asociación española de Entomología, which has greatly facilitated its preparation, edition and publication

Characterizing sampling and quality screening biases in infrared and microwave limb sounding

This study investigates orbital sampling biases and evaluates the additional impact caused by data quality screening for the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the Aura Microwave Limb Sounder (MLS). MIPAS acts as a proxy for typical infrared limb emission sounders, while MLS acts as a proxy for microwave limb sounders. These biases were calculated for temperature and several trace gases by interpolating model fields to real sampling patterns and, additionally, screening those locations as directed by their corresponding quality criteria. Both instruments have dense uniform sampling patterns typical of limb emission sounders, producing almost identical sampling biases. However, there is a substantial difference between the number of locations discarded. MIPAS, as a mid-infrared instrument, is very sensitive to clouds, and measurements affected by them are thus rejected from the analysis. For example, in the tropics, the MIPAS yield is strongly affected by clouds, while MLS is mostly unaffected. The results show that upper-tropospheric sampling biases in zonally averaged data, for both instruments, can be up to 10 to 30 %, depending on the species, and up to 3 K for temperature. For MIPAS, the sampling reduction due to quality screening worsens the biases, leading to values as large as 30 to 100 % for the trace gases and expanding the 3 K bias region for temperature. This type of sampling bias is largely induced by the geophysical origins of the screening (e.g. clouds). Further, analysis of long-term time series reveals that these additional quality screening biases may affect the ability to accurately detect upper-tropospheric long-term changes using such data. In contrast, MLS data quality screening removes sufficiently few points that no additional bias is introduced, although its penetration is limited to the upper troposphere, while MIPAS may cover well into the mid-troposphere in cloud-free scenarios. We emphasize that the results of this study refer only to the representativeness of the respective data, not to their intrinsic quality

Deformidad vertebral y mielomeningocele: actitud terapéutica y resultados

Presentamos nuestra experiencia en el tratamiento quirúrgico de la deformidad vertebral relacionada con el mielomeningocele entre los años 1972 y 1995. En ese período un total de 48 pacientes fueron intervenidos. Se han evaluado las condiciones generales previas, el estado prequirúrgico, las diversas modalidades de instrumentación y el resultado de las mismas, así como el tipo y número de complicaciones. Durante el período posquirúrgico inmediato hemos encontrado un porcentaje de infecciones del 68%. Sin embargo, el resultado final, tanto del equilibrio pélvico como del vertebral conseguido, no estuvo influenciado significativamente por esta complicación. El tipo de patología, las complicaciones generales derivadas de la misma, el tiempo quirúrgico empleado y las pérdidas sanguíneas, son condiciones estrechamente relacionadas con el número de infecciones encontradas.We present our experience on the surgical treatment of myelomeningocelelinked vertebral deformity between 1972 and 1995. We evaluated the previous general condition, the presurgical status, the instrument modalities and their outcome, as well as the type and number of complications in a series of 48 patients. During the immediate postoperative period, we found a 68% infection rate. However, the end result for pelvic as well as vertebral balance was not influenced significantly by this complication. The number of infections found is closely linked to the specific pathology, the complications, duration of operation, and blood loss

Complicaciones sépticas de la osteosíntesis lumbosacra: Análisis de 23 casos

Entre 1987 y 1995 hemos intervenido 295 pacientes afectos de patología lumbosacra realizando en todos ellos una artrodesis instrumentada. Veintitrés pacientes tuvieron como complicación una infección profunda, lo que equivale a un 7,8%. El germen más frecuentemente aislado como responsable de la infección fue el Staphylococcus aureus resistente a la meticilina. La antibioterapia más veces utilizada fue una cefalosporina de 2.a generación. La infección se resolvió en 4 ocasiones bajo tratamiento médico; sin embargo, en 19 se procedió a limpieza quirúrgica de los tejidos dañados no siendo necesaria la retirada del material de osteosíntesis. En 9 ocasiones se practicó una 2.a reintervención, y en otros 4 una tercera. En nuestra serie, fue necesario reintervenir quirúrgicamente el 50% de los pacientes a los que se practicó una limpieza quirúrgica. Dado que la profilaxis antibiótica debe de cubrir los gérmenes prevalentes en cada unidad hospitalaria, de acuerdo con su patrón de resistencia, hubiera sido más adecuado el empleo de antibióticos glucopeptídicos.Between 1987 and 1995 we performed an instrumented arthrodesis on 295 patients with lumbosacral pathology and 23 patients (7.8%) had a serious infection. Methicillin-resistent Staphylococcus aureus was the most frequently isolated causal germs. Second generation Cephalosporin was the antibiotic administered the most. The infection was cured in 4 cases with medical treatment. However, in 19 patients surgical cleaning of the damaged tissue was required, although it was not necessary to remove the osteosynthesis material. In 9 cases a second operation was performed and a third in 4 others. In our series, 50% of the patients who required surgical cleaning underwent another operation. Due to the fact that prophylactic antibiotics should cover the germs prevalent in each hospital ward, according to the resistence patterns, the use of Glycopeptid antibiotics would have been more appropriate

Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada - Part 2: Future change in cryosphere, vegetation, and hydrology

Global reanalyses from data assimilation systems are among the most widely used datasets in weather and climate studies, and potential vorticity (PV) from reanalyses is invaluable for many studies of dynamical and transport processes. We assess how consistently modern reanalyses represent potential vorticity (PV) among each other, focusing not only on PV but also on process-oriented dynamical diagnostics including equivalent latitude calculated from PV and PV-based tropopause and stratospheric polar vortex characterization. In particular we assess the National Centers for Environmental Prediction Climate Forecast System Reanalysis/Climate Forecast System, version 2 (CFSR/CFSv2) reanalysis, the European Centre for Medium-Range Weather Forecasts Interim (ERA-Interim) reanalysis, the Japanese Meteorological Agency's 55-year (JRA-55) reanalysis, and the NASA Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2). Overall, PV from all reanalyses agrees well with the reanalysis ensemble mean, providing some confidence that all of these recent reanalyses are suitable for most studies using PV-based diagnostics. Specific diagnostics where some larger differences are seen include PV-based tropopause locations in regions that have strong tropopause gradients (such as around the subtropical jets) or are sparse in high-resolution data (such as over Antarctica), and the stratospheric polar vortices during fall vortex formation and (especially) spring vortex breakup; studies of sensitive situations or regions such as these should examine PV from multiple reanalyses. &nbsp;</p

Adjustable conduits for guided peripheral nerve regeneration prepared from bi-zonal unidirectional and multidirectional laminar scaffold of type I collagen

Shortness of donor nerves has led to the development of nerve conduits that connect sectioned peripheral nerve stumps and help to prevent the formation of neuromas. Often, the standard diameters of these devices cannot be adapted at the time of surgery to the diameter of the nerve injured. In this work, scaffolds were developed to form filled nerve conduits with an inner matrix with unidirectional channels covered by a multidirectional pore zone. Collagen type I dispersions (5 mg/g and 8 mg/g) were sequentially frozen using different methods to obtain six laminar scaffolds (P1 to P5) formed by a unidirectional (U) pore/channel zone adjacent to a multidirectional (M) pore zone. The physicochemical and microstructural properties of the scaffolds were determined and compared, as well as their biodegradability, residual glutaraldehyde and cytocompatibility. Also, the Young's modulus of the conduits made by rolling up the bizonal scaffolds from the unidirectional to the multidirectional zone was determined. Based on these comparisons, the proliferation and differentiation of hASC were assessed only in the P3 scaffolds. The cells adhered, aligned in the same direction as the unidirectional porous fibers, proliferated, and differentiated into Schwann-like cells. Adjustable conduits made with the P3 scaffold were implanted in rats 10 mm sciatic nerve lesions to compare their performance with that of autologous sciatic nerve grafted lesions. The in vivo results demonstrated that the tested conduit can be adapted to the diameter of the nerve stumps to guide their growth and promote their regeneration.publishe

Optical and clinical outcomes of an enhanced monofocal intraocular lens for high hyperopia

Purpose: To evaluate the optical and clinical performance of an enhanced monofocal intraocular lens (IOL) (TECNIS Eyhance ICB00; Johnson & Johnson Vision) in patients with high hyperopia and a short axial length. Methods: Power mapping, wavefront analysis, and the through-focus modulation transfer function area (TF-MTFa) were measured in vitro for three IOL powers (10.00, 20.00, and 30.00 diopters [D]). The clinical study included 22 patients with an axial length of less than 22.5 mm. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and binocular defocus curve were evaluated 6 months postoperatively. Results: For the three IOL powers, the power mapping revealed an increase in positive power from the periphery to the center of the lens, providing an extra positive correction of 1.00 D for a 2-mm pupil size. The TF-MTFa curves showed only a peak of maximum MTFa at the distance focus. As the pupil size became smaller, there was a focus extension effect, providing an extended depth of focus of up to -1.50 D for a 2-mm pupil size. No significant dependency of the IOL base power on the power profile, wavefront, or optical quality was found. The clinical outcomes showed that all patients achieved a binocular CDVA of 0.1 logMAR or better. The mean visual acuity was better than 0.1 logMAR between +0.50 and -1.50 D of defocus. At a vergence of -2.00 D, the visual acuity was 0.11 ± 0.13 logMAR. Conclusions: The monofocal enhanced IOL provided good distance optical and visual quality and optimal visual acuity up to an intermediate-near vision distance of 50 to 40 cm in patients with high hyperopia and a short axial length.Supported by Project PID2020-114582RB-I00/AEI/10.13039/501100011033 from the Spanish Agencia Estatal de InvestigaciónPeer ReviewedPostprint (author's final draft

Kinetic Analysis of Substrate Utilization by Native and TNAP-, NPP1-, or PHOSPHO1-Deficient Matrix Vesicles

During the process of endochondral bone formation, chondrocytes and osteoblasts mineralize their extracellular matrix by promoting the formation of hydroxyapatite seed crystals in the sheltered interior of membrane-limited matrix vesicles (MVs). Here, we have studied phosphosubstrate catalysis by osteoblast-derived MVs at physiologic pH, analyzing the hydrolysis of ATP, ADP, and PPi by isolated wild-type (WT) as well as TNAP-, NPP1- and PHOSPHO1-deficient MVs. Comparison of the catalytic efficiencies identified ATP as the main substrate hydrolyzed by WT MVs. The lack of TNAP had the most pronounced effect on the hydrolysis of all physiologic substrates. The lack of PHOSPHO1 affected ATP hydrolysis via a secondary reduction in the levels of TNAP in PHOSPHO1-deficient MVs. The lack of NPP1 did not significantly affect the kinetic parameters of hydrolysis when compared with WT MVs for any of the substrates. We conclude that TNAP is the enzyme that hydrolyzes both ATP and PPi in the MV compartment. NPP1 does not have a major role in PPi generation from ATP at the level of MVs, in contrast to its accepted role on the surface of the osteoblasts and chondrocytes, but rather acts as a phosphatase in the absence of TNAP. © 2010 American Society for Bone and Mineral Research