Cranial osteology and paleoneurology of Tarjadia ruthae: An erpetosuchid pseudosuchian from the Triassic Chañares Formation (late Ladinian-?early Carnian) of Argentina.

Tarjadia ruthae is a quadrupedal terrestrial pseudosuchian from the Middle-early Upper Triassic of the Chañares Formation, La Rioja Province, Argentina. Originally, this species was identified as an indeterminate archosaur and later as a doswelliid archosauriform based on very fragmentary specimens characterized by the ornamentation of the skull roof and osteoderms. Additional specimens (including skulls and postcrania) recovered in the last decade show that Tarjadia is an erpetosuchid, an enigmatic pseudosuchian group composed of six species registered in Middle-Upper Triassic continental units of Tanzania, Germany, Scotland, North America, Brazil, and Argentina. Tarjadia ruthae from Argentina and Parringtonia gracilis from Tanzania are the best preserved and more abundant species. Although the monophyly of Erpetosuchidae is well supported, alternative high-level positions within Archosauria have been suggested, such as sister taxon to Crocodylomorpha, Aetosauria, or Ornithosuchidae. In order to improve the knowledge about the erpetosuchids, we performed a detailed description and paleoneurological reconstruction of the skull of Tarjadia ruthae, based on two articulated partial skulls (CRILAR-Pv 478 and CRILAR-Pv 495) and other fragmentary specimens. We analyzed the stratigraphic and geographic occurrence of historical and new specimens of Tarjadia and provided a new emended diagnosis (the same for the genus as for the species, due to monotypy) along with a comparative description of the cranial endocast. The skull of Tarjadia is robust, with a thick and strongly ornamented skull roof, triangular in dorsal view, with concave lateral margins at mid-length that form an abrupt widened posterior region. The external nares are the smallest openings of the skull. The antorbital fossa is deeply excavated and has a small heart-shaped fenestra with both lobes pointing anteriorly. The supratemporal fenestrae are as large and rounded as the orbits, and the infratemporal fenestrae are L-shaped with an extensive excavation along the jugal, quadratojugal and quadrate. The hemimandibles are low, slightly concave on the dentigerous region and strongly convex on the posterior region, conferring them a S-shaped profile in dorsal view. The external mandibular fenestra is small and elliptic, being twice longer than high. The maxillary dentition is restricted to the anterior to mid region of the rostrum. Since the braincase of both specimens is partially damaged, the dorsal surface of the brain could not be entirely reconstructed. As a result, the endocast is anteroposteriorly elongated and seemingly flat, and the cephalic flexure seems to be lower than expected for a suchian. The labyrinth is twice wider than high, the semicircular canals are remarkably straight, and the anterior canal is longer than the posterior one.

Safety profile and SARS-CoV-2 breakthrough infections among HCWs receiving anti-SARS-CoV-2 and influenza vaccines simultaneously: an Italian observational study.

In October/December 2021, World Health Organization and other international agencies recommended the offer of the third dose of anti-SARS-CoV-2 vaccine. In this period, the routine offer of seasonal influenza vaccination was also guaranteed and simultaneous administration of the two vaccines was encouraged. This study aims to evaluate the safety profile and to estimate the incidence of SARS-CoV-2 breakthrough infections in subjects receiving the anti-SARS-CoV-2 and influenza vaccines simultaneously. The study population was represented by healthcare workers (HCWs) of Bari Policlinico General Hospital who received the influenza (Flucelvax Tetra®) and/or anti-SARS-CoV-2 vaccination (BNT162b2 mRNA COVID-19 vaccine, Comirnaty®) either in coadministration or separately in October 2021. Reports of adverse events following immunization (AEFIs) were investigated to study the safety of both vaccines in coadministration and in separate-instance administration. Post-vaccination SARS-CoV-2 breakthrough infection was also studied. 942 HCWs accepted to join our study. 610/942 received both vaccines simultaneously. 25.26 % subjects (238/942) were only vaccinated against SARS-CoV-2, while the remaining 94 HCWs received the influenza vaccination first and subsequently received the anti-SARS-CoV2 booster dose. 717 HCWs reported AEFIs (Reporting Rate 76.1 per 100 subjects). Simultaneous administration of the two vaccines was not related with an increase of the rate of AEFIs compared to the single administration of SARS-CoV-2 vaccine, but the AEFIs' rate was lower among subjects who received only influenza vaccine. Post-vaccination SARS-CoV-2 infections were notified for 41.5 % of enrolled subjects (391/942). Incidence of breakthrough infection and symptomatic disease was not significantly different between the simultaneous administration group and other subjects. Our data suggests that simultaneous administration of a quadrivalent influenza vaccine and an mRNA anti-SARS-CoV-2 vaccine neither affected the safety of said products nor was associated with a higher risk of SARS-CoV-2 breakthrough infection.

High-performance Fe(Se,Te) films on chemical CeO2-based buffer layers.

The fabrication of a Fe-based coated conductor (CC) becomes possible when Fe(Se,Te) is grown as an epitaxial film on a metallic oriented substrate. Thanks to the material's low structural anisotropy, less strict requirements on the template microstructure allow for the design of a simplified CC architecture with respect to the REBCO multi-layered layout. This design, though, still requires a buffer layer to promote the oriented growth of the superconducting film and avoid diffusion from the metallic template. In this work, Fe(Se,Te) films are grown on chemically-deposited, CeO2-based buffer layers via pulsed laser deposition, and excellent properties are obtained when a Fe(Se,Te) seed layer is used. Among all the employed characterization techniques, transmission electron microscopy proved essential to determine the actual effect of the seed layer on the final film properties. Also, systematic investigation of the full current transport properties J(θ, H, T) is carried out: Fe(Se,Te) samples are obtained with sharp superconducting transitions around 16 K and critical current densities exceeding 1 MA cm-2 at 4.2 K in self-field. The in-field and angular behavior of the sample are in line with data from the literature. These results are the demonstration of the feasibility of a Fe-based CC, with all the relative advantages concerning process simplification and cost reduction.

Extreme ultraviolet transient gratings: A tool for nanoscale photoacoustics.

Collective lattice dynamics determine essential aspects of condensed matter, such as elastic and thermal properties. These exhibit strong dependence on the length-scale, reflecting the marked wavevector dependence of lattice excitations. The extreme ultraviolet transient grating (EUV TG) approach has demonstrated the potential of accessing a wavevector range corresponding to the 10s of nm length-scale, representing a spatial scale of the highest relevance for fundamental physics and forefront technology, previously inaccessible by optical TG and other inelastic scattering methods. In this manuscript we report on the capabilities of this technique in the context of probing thermoelastic properties of matter, both in the bulk and at the surface, as well as discussing future developments and practical considerations.

The safety of pneumococcal vaccines at the time of sequential schedule: data from surveillance of adverse events following 13-valent conjugated pneumococcal and 23-valent polysaccharidic pneumococcal vaccines in newborns and the elderly, in Puglia (Italy), 2013-2020.

Background: Nowadays, two types of anti-pneumococcal vaccine are available: pneumococcal 13-valent conjugate vaccine (PCV13), first licensed in the United States (US) in 2013, and pneumococcal 23-valent polysaccaridic vaccine (PPSV23), first licensed in the US in 1999. These vaccines are recommended in Italy for the immunization of newborns and of the elderly, using a combined sequential schedule for the latter. This report aims to describe the PCV13- and PPSV23-related AEFIs notified in Puglia in 2013-2020, in order to design these products' safety profile in a real-life scenario, three years after the official recommendation about the sequential schedule for people over 60 years of age. Methods: This is a retrospective observational study. Data were gathered from the list of AEFIs notified following PCV13 and PPSV23 administration in Puglia in 2013-2020. The number of administered vaccine doses was obtained from the regional immunization database. AEFIs were classified according to WHO's algorithm, and causality assessment was carried out in case of serious AEFIs. Results: From January 2013 to December 2020, 764,183 doses of PCV13 and 40,382 doses of PPSV23 were administered in Puglia. In the same period, 71 PCV13 AEFIs (Reporting Rate: 9.29 x100,000 doses) and 5 PPSV23 AEFIs (Reporting Rate: 12.4 x100,000 doses) were reported. The overall male/female ratio in AEFIs was 0.85. The majority of AEFIs occurred in subjects aged less than 2 (64/76, 84.2%), while 10 out of 76 (13.2%) occurred in patients aged 60 or older. 22 AEFIs were classified as serious and for 12 (54.5%) causality assessment showed a consistent relationship with immunization. The most commonly reported symptoms were fever (Reporting Rate: 4.72 x100,000 doses) and neurological symptoms (Reporting Rate: 3.23 x100,000 doses). Only one death was notified, classified as non-vaccine-related. Conclusions: The benefit of pneumococcal vaccination appears to be greater than the risk of AEFIs for both PCV13 and PPSV23. In fact, AEFIs occur in less than 0.1‰ of patients and the majority of AEFIs are mild and self-limiting.

Incidence of SARS-COV-2 infection among swimming athletes: data from real life in Apulia (Italy), July 2020/August 2021.

Background: As other indoor sports facilities, swimming pools were closed in Italy from March to May 2020 and from October 2020 to July 2021 due to the outbreak of the COVID-19 pandemic; access to these facilities was restricted to athletes of national relevance. This decision was based on "precautionary principles" and without evidence of a high risk of SARS-COV-2 circulation among swimming pools' attendants. The aim of this paper is to describe the pattern of SARS-COV-2 circulation among swimming athletes in Apulia (Southern Italy). Study design: The study aims to investigate the hypothesis that attending a pool increases the risk of SARS-COV-2 infection. The outcome measure is the incidence of SARS-COV-2 infection among swimming athletes compared with the general population. Methods: This is a retrospective cross-sectional study carried out in Apulia, Southern Italy. The study was performed through the analysis of both the database of the Italian Swimming Federation and the SARS-COV-2 infections in Apulia Region, from July 2020 to August 2021. Results: Among 2,939 federally licensed athletes, 221 had an history of SARS-COV-2 infection from July 2020 to August 2021, with an incidence of 75.2 /1,000. In the general Apulian population, during the same time span, the incidence of SARS-COV-2 infection was 67.3/1,000 and - considering the incidence rate ratio - there is no difference between the two populations (IRR=1.1; 95% CI=0.9-1.3; p>0.05). Conclusions: The incidence of SARS-COV-2 infection in Apulian swimmers showed no significant differences with the general population.

LUNCH-Lung Ultrasound for early detection of silent and apparent aspiratioN in infants and young CHildren with cerebral palsy and other developmental disabilities: study protocol of a randomized controlled trial.

BACKGROUND: Children with neurological impairment may have dysphagia and/or gastro-esophageal reflux disease (GERD), which predispose to complications affecting the airways, increasing risk for aspiration-induced acute and chronic lung disease, or secondarily malnutrition, further neurodevelopmental disturbances, stressful interactions with their caregivers and chronic pain. Only multidisciplinary clinical feeding evaluation and empirical trials are applied to provide support to the management of feeding difficulties related to dysphagia or GERD, but no standardized feeding or behavioral measure exists at any age to assess aspiration risk and support the indication to perform a videofluoroscopic swallowing study (VFSS) or a fibre-optic endoscopic examination of swallowing (FEES), in particular in newborns and infants with neurological impairments. Lung ultrasound (LUS) has been proposed as a non-invasive, radiation-free tool for the diagnosis of pulmonary conditions in infants, with high sensitivity and specificity. METHODS: A RCT will be conducted in infants aged between 0 and 6 years having, or being at risk for, cerebral palsy, or other neurodevelopmental disease that determines abnormal muscular tone or motor developmental delay assessed by a quantitative scale for infants or if there is the suspicion of GERD or dysphagia based on clinical symptoms. Infants will be allocated in one of 2 groups: 1) LUS-monitored management (LUS-m); 2) Standard care management (SC-m) and after baseline assessment (T0), both groups will undergo an experimental 6-months follow-up. In the first 3 months, infants will be evaluated a minimum of 1 time per month, in-hospital, for a total of 3 LUS-monitored meal evaluations. Primary and secondary endpoint measures will be collected at 3 and 6 months. DISCUSSION: This paper describes the study protocol consisting of a RCT with two main objectives: (1) to evaluate the benefits of the use of LUS for monitoring silent and apparent aspiration in the management of dysphagia and its impact on pulmonary illness and growth and (2) to investigate the impact of the LUS management on blood sample and bone metabolism, pain and interaction with caregivers. TRIAL REGISTRATION: Trial registration date 02/05/2020; ClinicalTrials.gov Identifier: NCT04253951 .

Bacterial biofilms on medical masks disposed in the marine environment: a hotspot of biological and functional diversity.

The present paper was aimed at investigating the role of disposable medical masks as a substrate for microbial biofilm growth and for the selection of specific microbial traits in highly impacted marine environments. In this view, we have immerged masks in a coastal area affected by a continuous input of artisanal fishery wastes and hydrocarbons pollution caused by intense maritime traffic. Masks maintained one month in the field were colonized by a bacterial community significantly different from that detected in the natural matrices from the same areas (seawater and sediments). The masks served as a viable substrate for the growth and enrichment of phototrophic microorganisms (Oxyphotobacteria), as well as Ruminococcaceae, Gracilibacteria, and Holophageae. In a follow-up investigation, masks previously colonized in the field were transferred in lab-scale microcosms which were supplemented with hydrocarbons and which contained also a piece of a virgin mask. After one month, a shift in the community composition, likely triggered by hydrocarbons addition, was observed in the previously colonized mask, with signatures characteristic of hydrocarbon-degrading microbial groups. Such hydrocarbon-degrading bacteria were also found to colonize the virgin mask. Remarkably, SEM micrographs provided indications of the occurrence of morphological modifications of the surface components of the virgin masks colonized by hydrocarbonoclastic bacteria. Overall, for the first time, we have demonstrated the potential risk for human and animal health determined by the uncorrected disposal of masks which are suitable substrates for pathogens colonization, permanence and spreading. Moreover, we have herein strengthened the knowledge on the role of hydrocarbon-degrading bacteria in the colonization and modification of fossil-based plastics in marine environment.

Delayed Auditory Brainstem Responses (ABR) in children after sight-recovery.

Studies in non-human animal models have revealed that in early development, the onset of visual input gates the critical period closure of some auditory functions. The study of rare individuals whose sight was restored after a period of congenital blindness offers the rare opportunity to assess whether early visual input is a prerequisite for the full development of auditory functions in humans as well. Here, we investigated whether a few months of delayed visual onset would affect the development of Auditory Brainstem Responses (ABRs). ABRs are widely used in the clinical practice to assess both functionality and development of the subcortical auditory pathway and, provide reliable data at the individual level. We collected Auditory Brainstem Responses from two case studies, young children (both having less than 5 years of age) who experienced a transient visual deprivation since birth due to congenital bilateral dense cataracts (BC), and who acquired sight at about two months of age. As controls, we tested 41 children (sighted controls, SC) with typical development, as well as two children who were treated (at about two months of age) for congenital monocular cataracts (MC). The SC group data served to predict, at the individual level, wave latencies of each BC and MC participant. Statistics were performed both at the single subject as well as at the group levels on latencies of main ABR waves (I, III, V and SN10). Results revealed delayed response latencies for both BC children compared with the SC group starting from the wave III. Conversely, no difference emerged between MC children and the SC group. These findings suggest that in case the onset of patterned visual input is delayed, the functional development of the subcortical auditory pathway lags behind typical developmental trajectories. Ultimately results are in favor of the presence of a crossmodal sensitive period in the human subcortical auditory system.

Mn-induced Fermi-surface reconstruction in the SmFeAsO parent compound.

The electronic ground state of iron-based materials is unusually sensitive to electronic correlations. Among others, its delicate balance is profoundly affected by the insertion of magnetic impurities in the FeAs layers. Here, we address the effects of Fe-to-Mn substitution in the non-superconducting Sm-1111 pnictide parent compound via a comparative study of SmFe[Formula: see text]Mn[Formula: see text]AsO samples with [Formula: see text] 0.05 and 0.10. Magnetization, Hall effect, and muon-spin spectroscopy data provide a coherent picture, indicating a weakening of the commensurate Fe spin-density-wave (SDW) order, as shown by the lowering of the SDW transition temperature [Formula: see text] with increasing Mn content, and the unexpected appearance of another magnetic order, occurring at [Formula: see text] and 20 K for [Formula: see text] and 0.10, respectively. We attribute the new magnetic transition at [Formula: see text], occurring well inside the SDW phase, to a reorganization of the Fermi surface due to Fe-to-Mn substitutions. These give rise to enhanced magnetic fluctuations along the incommensurate wavevector [Formula: see text], further increased by the RKKY interactions among Mn impurities.

Aggression differentially modulates neural correlates of social intention attribution to benevolent, tickling and taunting laughter: An fMRI study in children and adolescents.

Human laughter is a powerful means of communicating social intention, ranging from welcoming and friendly to hostile and ridiculing. To be communicated accurately, the recipient must correctly identify the laugher's underlying social intention. Regular misattribution of the social intention of others has been associated with maladaptive psychosocial development, in particular with aggressive behavior. We investigated the relationship between self-reported aggressive behavior and the neural correlates of social intention attributions to different audiovisual laughter types in 50 healthy children and adolescents (29 female, 10-18 years, M 15.5, SD 2.2) using functional magnetic resonance imaging. Trial-by-trial associations of neural response and behavioral attributions were distinctly modulated by aggression for benevolent versus taunting and tickling laughter. With increasing aggression, hostile misattributions of benevolent laughter were associated with decreased dorsolateral prefrontal and anterior insular cortex activation. In contrast, hostile attributions of taunting and tickling laughter were associated with increased superior frontal, superior temporal, medial prefrontal, supplementary motor, and anterior and mid-cingulate cortex activation. We argue that aggression may be associated with down-regulated emotional saliency of benevolent laughter, whereas up-regulated neural responses to taunting laughter may underlie a heightened sensitivity to hostility or acceptance of taunting behavior in more aggressive individuals.

Photobiomodulation modulates the expression of inflammatory cytokines during the compensatory hypertrophy process in skeletal muscle.

Compensatory hypertrophy (CH) occurs due to excessive mechanical load on a muscle, promoting an increase in the size of muscle fibers. In clinical practice, situations such as partial nerve injuries, denervation, and muscle imbalance caused by trauma to muscles and nerves or diseases that promote the loss of nerve conduction can induce CH in muscle fibers. Photobiomodulation (PBM) has demonstrated beneficial effects on muscle tissue during CH. The aim of the present study was to evaluate the effect of PBM on the inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) as well as type 2 metalloproteinases (MMP-2) during the process of CH due to excessive load on the plantaris muscle in rats. Forty-five Wistar rats weighing 250 g were divided into three groups: control group (n = 10), hypertrophy (H) group (n = 40), and H + PBM group (n = 40). CH was induced through the ablation of synergist muscles of the plantaris muscle. The tendons of the gastrocnemius and soleus muscles were isolated and sectioned to enable the partial removal of each of muscle. The preserved plantaris muscle below the removed muscles was submitted to excessive functional load. PBM was performed with low-level laser (AsGaAl, λ = 780 nm; 40 mW; energy density: 10 J/cm2; 10 s on each point, 8 points; 3.2 J). Animals from each group were euthanized after 7 and 14 days. The plantaris muscles were carefully removed and sent for analysis of the gene and protein expression of IL-6 and TNF-α using qPCR and ELISA, respectively. MMP-2 activity was analyzed using zymography. The results were submitted to statistical analysis (ANOVA + Tukey's test, p < 0.05). The protein expression analysis revealed an increase in IL-6 levels in the H + PBM group compared to the H group and a reduction in the H group compared to the control group. A reduction in TNF-α was found in the H and H + PBM groups compared to the control group at 7 days. The gene expression analysis revealed an increase in IL-6 in the H + PBM group compared to the H group at 14 days as well as an increase in TNF-α in the H + PBM group compared to the H group at 7 days. Increases in MMP-2 were found in the H and H + PBM groups compared to the control group at both 7 and 14 days. Based on findings in the present study, it is concluded that PBM was able to modulate pro-inflammatory cytokines that are essential for the compensatory hypertrophy process. However, it has not shown a modulation effect directly in MMP-2 activity during the same period evaluated.

Mn substitution effect on the local structure of La(Fe1-x Mn x )AsO studied by temperature dependent x-ray absorption measurements.

The local structure of La(Fe1-x Mn x )AsO has been investigated using temperature dependent Fe K-edge extended x-ray absorption fine structure (EXAFS) measurements. The EXAFS data reveal distinct behavior of Fe-As and Fe-Fe atomic displacements with a clear boundary between x ⩽ 0.02 and x > 0.02. The Fe-As bondlength shows a gradual thermal expansion while the Fe-Fe bond manifests a temperature dependent anomaly at ∼180 K for x > 0.02. It is interesting to find characteristically different nature of Fe-As and Fe-Fe bondlengths shown by the temperature dependent mean square relative displacements. Indeed, the Fe-As bond, stiffer than that of the Fe-Fe, gets softer for x ⩽ 0.02 and hardly shows any change for x > 0.02. On the other hand, Fe-Fe bond tends to be stiffer for x ⩽ 0.02 followed by a substantial softening for x > 0.02. Such a distinction has been seen also in the As K-edge x-ray absorption near edge structure, probing local geometry around As atom together with the valence electronic structure. The results suggest that local atomic displacements by Mn substitution inducing increased iron local magnetic moment that should be the main reason for its dramatic effect in iron-based superconductors.

Marine hydrocarbon-degrading bacteria breakdown poly(ethylene terephthalate) (PET).

Pollution of aquatic ecosystems by plastic wastes poses severe environmental and health problems and has prompted scientific investigations on the fate and factors contributing to the modification of plastics in the marine environment. Here, we investigated, by means of microcosm studies, the role of hydrocarbon-degrading bacteria in the degradation of poly(ethylene terephthalate) (PET), the main constituents of plastic bottles, in the marine environment. To this aim, different bacterial consortia, previously acclimated to representative hydrocarbons fractions namely, tetradecane (aliphatic fraction), diesel (mixture of hydrocarbons), and naphthalene/phenantrene (aromatic fraction), were used as inocula of microcosm experiments, in order to identify peculiar specialization in poly(ethylene terephthalate) degradation. Upon formation of a mature biofilm on the surface of poly(ethylene terephthalate) films, the bacterial biodiversity and degradation efficiency of each selected consortium was analyzed. Notably, significant differences on biofilm biodiversity were observed with distinctive hydrocarbons-degraders being enriched on poly(ethylene terephthalate) surface, such as Alcanivorax, Hyphomonas, and Cycloclasticus species. Interestingly, ATR-FTIR analyses, supported by SEM and water contact angle measurements, revealed major alterations of the surface chemistry and morphology of PET films, mainly driven by the bacterial consortia enriched on tetradecane and diesel. Distinctive signatures of microbial activity were the alteration of the FTIR spectra as a consequence of PET chain scission through the hydrolysis of the ester bond, the increased sample hydrophobicity as well as the formation of small cracks and cavities on the surface of the film. In conclusion, our study demonstrates for the first time that hydrocarbons-degrading marine bacteria have the potential to degrade poly(ethylene terephthalate), although their degradative activity could potentially trigger the formation of harmful microplastics in the marine environment.

Microscopic pathways for stress relaxation in repulsive colloidal glasses.

Residual stresses are well-known companions of all glassy materials. They affect and, in many cases, even strongly modify important material properties like the mechanical response and the optical transparency. The mechanisms through which stresses affect such properties are, in many cases, still under study, and their full understanding can pave the way to a full exploitation of stress as a primary control parameter. It is, for example, known that stresses promote particle mobility at small length scales, e.g., in colloidal glasses, gels, and metallic glasses, but this connection still remains essentially qualitative. Exploiting a preparation protocol that leads to colloidal glasses with an exceptionally directional built-in stress field, we characterize the stress-induced dynamics and show that it can be visualized as a collection of "flickering," mobile regions with linear sizes of the order of ≈20 particle diameters (≈2 µm here) that move cooperatively, displaying an overall stationary but locally ballistic dynamics.

Nanoscale transient gratings excited and probed by extreme ultraviolet femtosecond pulses.

Advances in developing ultrafast coherent sources operating at extreme ultraviolet (EUV) and x-ray wavelengths allow the extension of nonlinear optical techniques to shorter wavelengths. Here, we describe EUV transient grating spectroscopy, in which two crossed femtosecond EUV pulses produce spatially periodic nanoscale excitations in the sample and their dynamics is probed via diffraction of a third time-delayed EUV pulse. The use of radiation with wavelengths down to 13.3 nm allowed us to produce transient gratings with periods as short as 28 nm and observe thermal and coherent phonon dynamics in crystalline silicon and amorphous silicon nitride. This approach allows measurements of thermal transport on the ~10-nm scale, where the two samples show different heat transport regimes, and can be applied to study other phenomena showing nontrivial behaviors at the nanoscale, such as structural relaxations in complex liquids and ultrafast magnetic dynamics.

Structural and magnetic properties of the Yb2Pd2(In1-x Sn x ) system: a synchrotron x-ray and neutron powder diffraction investigation.

The structural properties of the Yb2Pd2(In1-x Sn x ) system were investigated at room temperature by synchrotron x-ray powder diffraction. All the inspected compositions (x = 0.0, 0.3, 0.4, 0.5, 0.6, 0.8, 0.9) crystallize in the tetragonal space group P4/mbm; the cell parameters exhibit a non-linear dependence on composition, whereas cell volume changes more regularly, with a minimum at x = 0.8. Samples with Sn content x = 0.5, 0.6, 0.9 were also analysed by neutron diffraction down to 0.5 K. No evidence for a structural transition can be detected at low temperature, whereas an antiferromagnetic ordering is observed, characterized by a propagation vectors k = (0,0,½). Magnetic moments order in the tetragonal ab-plane and the magnetic structure belongs to the Shubnikov magnetic space group P4/mbm.

Fast recovery of the pristine magnetic and structural phases in superconducting LaFeAsO0.89F0.11 by Mn/Fe substitution.

We report an experimental study on the effect of Mn impurities in the optimally doped [Formula: see text] compound. The results show that a very tiny amount of Mn, of the order of 0.1%, is enough to destroy superconductivity and to recover at low temperatures both the magnetic ground state and the orthorhombic structure of the pristine LaFeAsO parent compound. The results are discussed within a model where electron correlations enhance the Ruderman-Kittel-Kasuya-Yosida interaction among impurities.

The huge effect of Mn substitution on the structural and magnetic properties of LaFeAsO: the La(Fe,Mn)AsO system.

The substitution of Mn for Fe on the sub-lattice in LaFeAsO has a remarkable impact on both structural and magnetic properties; for example, the structural and magnetic transition temperatures decrease of ~20 K in samples with a Mn-content as low as x = 0.01. Such a dramatic effect results from the high stability of the substituting Mn2+ ion (3d 5) in its high-spin state, which opposes any variation to its electronic state (configuration), perturbing thereby interactions within the Fe sub-lattice between the Fe ions surrounding the substituent. Several investigations ascertained that the structural transformation in LnFeAsO compounds (Ln: lanthanide) cannot be ascribed to lattice degrees of freedom, but rather to electronic or spin ones. In this context, even an extremely low concentration of Mn2+ ions diluted in the Fe sub-lattice produces a reduction of the electronic degree of freedom of the system, thus hindering the structural transformation and the magnetic transition.