Early Formation Research Articles

Immediate Sequential Bilateral Implantable Collamer Lens Surgery Is Safe and Effective.

To assess the clinical outcomes and safety profiles of patients who underwent immediate sequential bilateral phakic lens surgery. This retrospective multicenter study included 254 consecutive patients (508 eyes) who underwent bilateral same-day Implantable Collamer Lens (ICL) (STAAR Surgical) surgery. The authors focused on 1-year postoperative clinical outcomes and adverse events. In the initial cohort, 176 patients (352 eyes) met inclusion criteria. Of these, 335 eyes underwent myopic ICL placement, and 17 eyes received a hyperopic ICL. Notably, 87% of eyes achieved ±0.50 diopters (D) and 95% achieved ±1.00 D of the intended refraction. One year postoperatively, 78% of eyes demonstrated optimal vaulting (250 to 750 µm), with a significant 19% reduction in vaulting observed over the 12 months (P < .001). Only minor adverse events, including early cataract formation (1 case), secondary toric ICL rotation (3 cases), and ICL exchange due to inappropriate vaulting (6 cases), were noted. The findings corroborate the safety and efficacy of immediate sequential bilateral phakic lens surgery and indicate its potential as a treatment option. The low incidence of minor adverse events further reinforces its favorable safety profile. [J Refract Surg. 2024;40(5):e313-e320.].

Simulations of early structure formation: Properties of halos that host primordial star formation

Context. Population III (pop III) stars were born in halos characterised by a pristine gas composition. In such a halo, once the gas density reaches nH ∼ 1 cm−3, molecular cooling leads to the collapse of the gas and the birth of pop III stars. Halo properties, such as the chemical abundances, mass, and angular momentum can affect the collapse of the gas, thereby leading to the pop III initial mass function (IMF) of star formation. Aims. We want to study the properties of primordial halos and how halos that host early star formation differ from other types of halos. The aim of this study is to obtain a representative population of halos at a given redshift hosting a cold and massive gas cloud that enables the birth of the first stars. Methods. We investigated the growth of primordial halos in a ΛCDM Universe in a large cosmological simulation. We used the hydrodynamic code RAMSES and the chemical solver KROME to study halo formation with non-equilibrium thermochemistry. We then identified structures in the dark and baryonic matter fields, thereby linking the presence or absence of dense gas clouds to the mass and the physical properties of the hosting halos. Results. In our simulations, the mass threshold for a halo for hosting a cold dense gas cloud is ≃7 × 105 M⊙ and the threshold in the H2 mass fraction is found to be ≃2 × 10−4. This is in agreement with previous works. We find that the halo history and accretion rate play a minor role. Here, we present halos with higher HD abundances, which are shown to be colder, as the temperature in the range between 102 − 104 cm−3 depends on the HD abundance to a large extent. The higher fraction of HD is linked to the higher spin parameter that is seen for the dense gas.

Evaluation of The Relationship Between Dental and Cervical Vertebrae Maturation in Terms of Age Determination

Aim: Age determination is a very important issue in anthropology, forensic science, and dentistry. Today, the most commonly used methods for age determination are the methods in which tooth and bone development are evaluated. This study aims to evaluate the relationship between gender, chronological age, dental maturation, and cervical vertebral maturation in individuals aged 8-25 years. Material and Method: Digital panoramic, lateral cephalometric radiographs of 500 patients aged 8-25 years were used in this study. Cervical vertebra maturation was evaluated using the dental maturation-modified Demirjian classification system of Baccetti et al. Means, minimum, maximum, and standard deviations were calculated and analyzed as descriptive statistics. Kolmogorov-Smirnov, Kappa, Kruskal-Wallis, Chi-Square, Linear Regression, and Spearman Correlation tests were used for statistical analysis. Results: There was a statistically significant difference between chronological age and dental maturation and cervical vertebral maturation levels (p &lt;0.01). While dental maturation levels did not differ significantly according to gender (p&gt; 0.05), cervical vertebra maturation was statistically different (p &lt;0.01). There was a positive correlation between chronological age and dental maturation, and cervical vertebral maturation levels (p &lt;0.01). There was a strong correlation between dental maturation and cervical vertebral maturation levels (p &lt;0.01). Conclusion: The findings of this study showed that skeletal maturity increased with the increase in chronological and dental age for both genders. The earlier formation was consistently observed for each stage of skeletal maturation in females. All correlations between skeletal and dental maturations were statistically significant.

Palladium(II)-catalyzed annulation of N-methoxy amides and arynes: computational mechanistic insights and substituents effects.

The combined use of transition metal-catalyzed C-H activation with aryne annulation reactions has emerged as an important strategy in organic synthesis. In this study, the mechanisms of the palladium(II)-catalyzed annulation reaction of N-methoxy amides and arynes were computationally investigated by density functional theory. The role of methoxy amide as a directing group was elucidated through the calculation of three different pathways for the C-H activation step, showing that the pathway where amide nitrogen acts as a directing group is preferable. At the reductive elimination transition state, an unstable seven-membered ring is formed preventing the lactam formation. A substituent effect study based on an NBO analysis, Hammet, and using a More O'Ferall-Jenks plot indicates that the C-H activation step proceeds via an electrophilic concerted metalation-deprotonation (eCMD) mechanism. The results show that electron-withdrawing groups increase the activation barrier and contribute to an early Pd-C bond formation and a late C-H bond breaking when compared with electron-donating substituents. Our computational results are in agreement with the experimental data provided in the literature. All calculations were performed using Gaussian 16 software. Geometry optimizations, frequency analyses at 393.15 K, and IRC calculations were conducted at the M06L/Def2-SVP level of theory. Corrected electronic energies, NBO charges, and Wiberg bond indexes were computed at the M06L/Def2-TZVP//M06L/Def2-SVP level of theory. Implicit solvent effects were considered in all calculations using the SMD model, with acetonitrile employed as the solvent.

The GALAH survey: tracing the Milky Way’s formation and evolution through RR Lyrae stars

ABSTRACT Stellar mergers and accretion events have been crucial in shaping the evolution of the Milky Way (MW). These events have been dynamically identified and chemically characterized using red giants and main-sequence stars. RR Lyrae (RRL) variables can play a crucial role in tracing the early formation of the MW since they are ubiquitous, old (t ≥ 10 Gyr) low-mass stars and accurate distance indicators. We exploited Data Release 3 of the GALAH survey to identify 78 field RRLs suitable for chemical analysis. Using synthetic spectra calculations, we determined atmospheric parameters and abundances of Fe, Mg, Ca, Y, and Ba. Most of our stars exhibit halo-like chemical compositions, with an iron peak around [Fe/H] ≈ −1.40, and enhanced Ca and Mg content. Notably, we discovered a metal-rich tail, with [Fe/H] values ranging from −1 to approximately solar metallicity. This sub-group includes almost 1/4 of the sample, it is characterized by thin disc kinematics and displays sub-solar α-element abundances, marginally consistent with the majority of the MW stars. Surprisingly, they differ distinctly from typical MW disc stars in terms of the s-process elements Y and Ba. We took advantage of similar data available in the literature and built a total sample of 535 field RRLs for which we estimated kinematical and dynamical properties. We found that metal-rich RRLs (1/3 of the sample) likely represent an old component of the MW thin disc. We also detected RRLs with retrograde orbits and provided preliminary associations with the Gaia–Sausage–Enceladus, Helmi, Sequoia, Sagittarius, and Thamnos stellar streams.

Unraveling the kinematics of IZw18: A detailed study of ionized gas with MEGARA/GTC

This study offers an in-depth analysis of the kinematic behavior of ionized gas in IZw18, a galaxy notable for its extremely low metallicity and close proximity, utilizing data from MEGARA/GTC. We explored the structure and dynamics of the galaxy through Halpha line profiles, applying single and double Gaussian component fittings to create detailed maps of the luminosity, velocity, and velocity dispersion in the main body (MB) and halo regions. Additionally, we retrieved integrated spectra from various galactic regions to achieve a higher signal-to-noise ratio. In the MB, a rotational pattern is evident, yet a secondary, more complex kinematic pattern emerges from the double-component fitting, which is further enriched by the identification of a very broad component. Distinguished by a full width at half maximum of nearly 2000 km/s and a wide spatial extension, this component suggests a high-energy outflow and points toward large-scale, nonlocalized sources of high kinetic energy. Additionally, the observed significant velocity differences between the narrow and very broad components imply that these gases may occupy distinct spatial regions. This is potentially explained by high-density gas near the origin of the kinematic input, acting as a "wall" that reflects back the momentum of the gas. Regarding the halos, while the NE halo exhibits a tranquil state with low velocity dispersions, the SW halo presents higher velocities and more complex kinematics, indicative of diverse dynamic interactions. The identification of the very broad component across the MB and the high kinematic complexity in all regions of the galaxy points toward a scenario of widespread and subtle turbulent motion. This nuanced understanding of the kinematic behavior in IZw18, including the interplay of different gas components and the influence of internal structures, enhances our comprehension of the dynamics in blue compact dwarf galaxies. It may provide critical insights into early galaxy formation and the intricate kinematics characteristic of such environments.

Immunoproteasomal Inhibition With ONX-0914 Attenuates Atherosclerosis and Reduces White Adipose Tissue Mass and Metabolic Syndrome in Mice.

Atherosclerosis is the major underlying pathology of cardiovascular disease and is driven by dyslipidemia and inflammation. Inhibition of the immunoproteasome, a proteasome variant that is predominantly expressed by immune cells and plays an important role in antigen presentation, has been shown to have immunosuppressive effects. We assessed the effect of ONX-0914, an inhibitor of the immunoproteasomal catalytic subunits LMP7 (proteasome subunit β5i/large multifunctional peptidase 7) and LMP2 (proteasome subunit β1i/large multifunctional peptidase 2), on atherosclerosis and metabolism in LDLr-/- and APOE*3-Leiden.CETP mice. ONX-0914 treatment significantly reduced atherosclerosis, reduced dendritic cell and macrophage levels and their activation, as well as the levels of antigen-experienced T cells during early plaque formation, and Th1 cells in advanced atherosclerosis in young and aged mice in various immune compartments. Additionally, ONX-0914 treatment led to a strong reduction in white adipose tissue mass and adipocyte progenitors, which coincided with neutrophil and macrophage accumulation in white adipose tissue. ONX-0914 reduced intestinal triglyceride uptake and gastric emptying, likely contributing to the reduction in white adipose tissue mass, as ONX-0914 did not increase energy expenditure or reduce total food intake. Concomitant with the reduction in white adipose tissue mass upon ONX-0914 treatment, we observed improvements in markers of metabolic syndrome, including lowered plasma triglyceride levels, insulin levels, and fasting blood glucose. We propose that immunoproteasomal inhibition reduces 3 major causes underlying cardiovascular disease, dyslipidemia, metabolic syndrome, and inflammation and is a new target in drug development for atherosclerosis treatment.

Volcanic crustal structure of the western Hikurangi Plateau (New Zealand) from marine seismic reflection imaging

Seamounts and basaltic basement can influence deformation and mass fluxes within subduction zones. We examined seamounts and volcanic units across the western Hikurangi Plateau, near the Hikurangi subduction margin, New Zealand, with seismic reflection images. Volcanism at the Hikurangi Plateau occurred in at least three phases that we attribute to (1) Early Cretaceous large igneous province formation, the top of which is marked by laterally continuous and dipping wedges of reflections that we interpret as lava flows; (2) Late Cretaceous seamounts and volcaniclastics that erupted onto the crust of the Hikurangi Plateau and make up the majority of seamount volume and basement relief; and (3) late-stage, Pliocene volcanics that erupted through and adjacent to Cretaceous seamounts and younger sediments of the north-central Hikurangi Plateau. The Pliocene volcanoes do not appear to be strongly welded to the plateau basement and may be petit spot volcanoes that are related to the displacement and accumulation of hydrous transition zone melts. Large seamounts and volcaniclastic units are evenly distributed across most of the Hikurangi Plateau near the Hikurangi margin but are absent from the Pegasus Basin. Although faults are imaged throughout the basement of the Pegasus Basin, contemporary normal faulting of the Hikurangi Plateau is uncommon, except for a zone of Quaternary normal faults near the Pliocene volcanics. These trends indicate that the Hikurangi megathrust may be more influenced by volcanic structures in the north and central Hikurangi margin, where plateau rifting and voluminous seamount eruptions have more substantially overprinted the original Early Cretaceous basement.

Early Planet Formation in Embedded Disks (eDisk). XIII. Aligned Disks with Nonsettled Dust around the Newly Resolved Class 0 Protobinary R CrA IRAS 32

Young protostellar binary systems, with expected ages less than ∼105 yr, are little modified since birth, providing key clues to binary formation and evolution. We present a first look at the young, Class 0 binary protostellar system R CrA IRAS 32 from the Early Planet Formation in Embedded Disks ALMA large program, which observed the system in the 1.3 mm continuum emission, 12CO (2−1), 13CO (2−1), C18O (2−1), SO (65−54), and nine other molecular lines that trace disks, envelopes, shocks, and outflows. With a continuum resolution of ∼0.″03 (∼5 au, at a distance of 150 pc), we characterize the newly discovered binary system with a separation of 207 au, their circumstellar disks, and a circumbinary disklike structure. The circumstellar disk radii are 26.9 ± 0.3 and 22.8 ± 0.3 au for sources A and B, respectively, and their circumstellar disk dust masses are estimated as 22.5 ± 1.1 M ⊕ and 12.4 ± 0.6 M ⊕, respectively. The circumstellar disks and the circumbinary structure have well-aligned position angles and inclinations, indicating formation in a smooth, ordered process such as disk fragmentation. In addition, the circumstellar disks have a near/far-side asymmetry in the continuum emission, suggesting that the dust has yet to settle into a thin layer near the midplane. Spectral analysis of CO isotopologues reveals outflows that originate from both of the sources and possibly from the circumbinary disklike structure. Furthermore, we detect Keplerian rotation in the 13CO isotopologues toward both circumstellar disks and likely Keplerian rotation in the circumbinary structure; the latter suggests that it is probably a circumbinary disk.

Structure formation with primordial black holes to alleviate early star formation tension revealed by JWST

This Letter explores the potential role of primordial black holes (PBHs) to address cosmological tensions as the presence of more massive than expected galaxies at high redshifts, as indicated by recent James Webb Space Telescope observations. Motivated by inflation models that enhance the power at scales beyond the observable range that produce PBHs with Schechter-like mass functions, we aim to explain the excess of high redshift galaxies via a modification of the Lambda cold dark matter power spectrum that consists in adding (i) a blue spectral index $n_b$ at $k_ piv =10/$Mpc and (ii) Poisson and isocurvature contributions from massive PBHs that only make up $0.5&lt;!PCT!&gt;$ of the dark matter. We simulated these models using the SWIFT code and find an increased abundance of high redshift galaxies in simulations that include PBHs. We compared these models to estimates from James Webb Space Telescope observations. Unlike the Lambda cold dark matter model, the inclusion of PBHs allowed us to reproduce the the observations with reasonable values for the star formation efficiency. Furthermore, the power spectra we adopted potentially produce PBHs that can serve as seeds for supermassive black holes with masses $7.57 odot

Investigating cryopreserved PBMC functionality in an antigen-induced model of sarcoidosis granuloma formation

Sarcoidosis, a systemic inflammatory disease, poses challenges in understanding its etiology and variable clinical courses. Despite ongoing uncertainty about causative agents and genetic predisposition, granuloma formation remains its hallmark feature. To address this, we developed a validated in vitro human granuloma model using patient-derived peripheral blood mononuclear cells (PBMCs), offering a dynamic platform for studying early granuloma formation and sarcoidosis pathogenesis. However, a current limitation of this model is its dependence on freshly isolated PBMCs obtained from whole blood. While cryopreservation is a common method for long-term sample preservation, the biological effects of freezing and thawing PBMCs on granuloma formation remain unclear. This study aimed to assess the viability and functionality of cryopreserved sarcoidosis PBMCs within the granuloma model, revealing similar granulomatous responses to fresh cells and highlighting the potential of cryopreserved PBMCs as a valuable tool for studying sarcoidosis and related diseases.

Early Cretaceous bivalves of the Romualdo Formation, Araripe Basin, northeastern Brazil

The fossil-rich Romualdo Formation (late Aptian/early Albian), Araripe Basin, northeastern Brazil, contains world-renowned Fossillagerstätten characterized by exceptionally preserved fossils. Macroinvertebrates in this formation are primarily represented by mollusks, echinoids, and decapod crustaceans. Mollusk shells are abundant in certain stratigraphic intervals, forming coquinas or shell pavements. Despite recent advances in our understanding of the taxonomy of certain groups, comprehensive taxonomic studies are lacking for almost the entire bivalve fauna. Therefore, a detailed taxonomic analysis is presented here. The described bivalves include four new genera (Araripenomia, Ciceromya, Inversatella, Australoeocallista), and six new species (Araripenomia infirma, Inversatella cearensis, Ciceromya edentulosa, Australoeocallista juazeiroi, Legumen kaririense, and Corbulomima delicata), in addition to Musculus maroimensis, Crassatella maroimensis, “Myrtea” sp. and “Tellina” sp. This bivalve fauna mainly consists of cosmopolitan and endemic brackish/marine genera, with Tethyan affinities. The fauna is not homogeneously distributed in the sedimentary succession of the Romualdo Formation, but is constrained to the third order highstand systems tract. Bivalves recorded from muddy facies are strongly dominated by infaunal and semi-infaunal suspension feeders. Assemblages of the sand-dominated facies, with dense shell accumulations of semi-infaunal to epifaunal byssate and infaunal suspension feeders, were formed under shallow, higher energy conditions. Despite the degree of generic endemicity, the mytilids, anomiids, crassateliids, astartids, tellinids, and corbulids are related to the bivalve fauna of the Early Cretaceous Riachuelo Formation of the Sergipe-Alagoas Basin, as previously demonstrated for the bakevelliids and echinoids. Indeed, the Romualdo bivalve fauna is, in part, a modified and impoverished brackish/marine fauna of the Riachuelo Formation.

Identification of the subaerial unconformity, genesis, and distribution in Lower Triassic Baikouquan Formation, Mahu Sag, Junggar Basin, Western China

The genesis of unconformities involves multiple influences on basin formation and evolution, which affects the favorable reservoir and hydrocarbon distribution. Within the Early Triassic Baikouquan Formation in the Mahu Sag of the Junggar Basin, we identified subaerial unconformities (SU), namely SU1 and SU2. SU1 is characterized by regional, irregular valleys, whereas SU2 displays extensive lateral extent with comparatively lower relief. These distinctions stem from detailed analyses involving cores, well data, seismic profiles, and spatial distributions, enriching our understanding of SUs in the Junggar Basin. Key findings from our study include: (1) SU occurrences within the Baikouquan Formation span the falling-stage systems tract (FSST) and expanding system tract (EST), corresponding to relative lake level changes. SU1 emerges during descending lake levels, whereas SU2 develops during rising levels. (2) The extensive uplift of the Junggar Basin's perimeter, driven by the late Hercynian movement, heightened topographic gradient shapes a steeper lake shoreline profile, fostering SU development. Arid paleoclimatic conditions during the Permian-Triassic interval accelerate SU formation in the FSST. (3) SU typically comprises regional compound scour surfaces (RCS) and river intermittent exposure surfaces (IES). Continuous winnowing at RCS led to relatively high primary porosities, IES can develop better secondary porosity with superposed freshwater leaching. The investigation into the subaerial unconformity in the study area holds broader implications for comprehending depositional processes, reservoir distribution, and petroleum prospects, both locally and within a global lake basin context.

Early automated cerebral edema assessment following endovascular therapy: impact on stroke outcome.

Cerebral edema (CED) is associated with poorer outcome in patients with acute ischemic stroke (AIS). The aim of the study was to investigate the factors contributing to greater early CED formation in patients with AIS who underwent endovascular therapy (EVT) and its association with functional outcome. We conducted a multicenter cohort study of patients with an anterior circulation AIS undergoing EVT. The volume of cerebrospinal fluid (CSF) was extracted from baseline and 24-hour follow-up CT using an automated algorithm. The severity of CED was quantified by the percentage reduction in CSF volume between CT scans (∆CSF). The primary endpoint was a shift towards an unfavorable outcome, assessed by modified Rankin Scale (mRS) score at 3 months. Multivariable ordinal logistic regression analyses were performed. The ∆CSF threshold that predicted unfavorable outcome was selected using receiver operating characteristic curve analysis. We analyzed 201 patients (mean age 72.7 years, 47.8% women) in whom CED was assessable for 85.6%. Higher systolic blood pressure during EVT and failure to achieve modified Thrombolysis In Cerebral Infarction (mTICI) 3 were found to be independent predictors of greater CED. ∆CSF was independently associated with the probability of a one-point worsening in the mRS score (common odds ratio (cOR) 1.05, 95% CI 1.03 to 1.08) after adjusting for age, baseline mRS, National Institutes of Health Stroke Scale (NIHSS), and number of passes. Displacement of more than 25% of CSF was associated with an unfavorable outcome (OR 6.09, 95% CI 3.01 to 12.33) and mortality (OR 6.72, 95% CI 2.94 to 15.32). Early CED formation in patients undergoing EVT was affected by higher blood pressure and incomplete reperfusion. The extent of early CED, measured by automated ∆CSF, was associated with worse outcomes.

14-3-3τ as a Modulator of Early α-Synuclein Multimerization and Amyloid Formation.

The aggregation of α-synuclein (αS) plays a key role in Parkinson's disease (PD) etiology. While the onset of PD is age-related, the cellular quality control system appears to regulate αS aggregation throughout most human life. Intriguingly, the protein 14-3-3τ has been demonstrated to delay αS aggregation and the onset of PD in various models. However, the molecular mechanisms behind this delay remain elusive. Our study confirms the delay in αS aggregation by 14-3-3τ, unveiling a concentration-dependent relation. Utilizing microscale thermophoresis (MST) and single-molecule burst analysis, we quantified the early αS multimers and concluded that these multimers exhibit properties that classify them as nanoscale condensates that form in a cooperative process, preceding the critical nucleus for fibril formation. Significantly, the αS multimer formation mechanism changes dramatically in the presence of scaffold protein 14-3-3τ. Our data modeling suggests that 14-3-3τ modulates the multimerization process, leading to the creation of mixed multimers or co-condensates, comprising both αS and 14-3-3τ. These mixed multimers form in a noncooperative process. They are smaller, more numerous, and distinctively not on the pathway to amyloid formation. Importantly, 14-3-3τ thus acts in the very early stage of αS multimerization, ensuring that αS does not aggregate but remains soluble and functional. This offers long-sought novel entries for the pharmacological modulation of PD.

Why together? Archaeology and zoology about medieval leather products on the example of Szczecin

Abstract Many years of archaeological excavation brought to light a rich material, that can be used in research of topics important from a social and economic point of view, such as the character of the production and/or organization, the development of technique and production technology, or the assortment of goods. A deep analysis of the selected categories of artifacts, in this case made of leather, can be used for a double purpose – a reconstruction of the process and conditions of early medieval leather craft formation, as well as a presentation of their role and significance in the activity structure of the inhabitants of Szczecin. Such an attempt to grasp the rules governing the development of one of the most important production branches – leatherworking, has been undertaken on the basis of leather objects that can be found on a mass scale in Szczecin’s cultural layers dated for the period from the early 10th to the mid-13th century. Key to these studies are the results of zoological analyses, which perfectly complement the archaeological conclusions.

On the origin of globular clusters in a hierarchical universe

ABSTRACT We present an end-to-end description of the formation of globular clusters (GCs) combining a treatment for their formation and dynamical evolution within galaxy haloes with a state-of-the-art semi-analytic simulation of galaxy formation. Our approach allows us to obtain exquisite statistics to study the effect of the environment and assembly history of galaxies, while still allowing a very efficient exploration of the parameter space. Our reference model, including both efficient cluster disruption during galaxy mergers and dynamical friction of GCs within the galactic potential, accurately reproduces the observed correlation between the total mass in GCs and the parent halo mass. A deviation from linearity is predicted at low-halo masses, which is driven by a strong dependence on morphological type: bulge-dominated galaxies tend to host larger masses of GCs than their later-type counterparts. While the significance of the difference might be affected by resolution at the lowest halo masses considered, this is a robust prediction of our model and a natural consequence of the assumption that cluster migration into the halo is triggered by galaxy mergers. Our model requires an environmental dependence of GC radii to reproduce the observed low-mass mass distribution of GCs in our Galaxy. At GC masses $\gt 10^6\, {\rm M}_\odot$, our model predicts fewer GCs than observed, due to an overly aggressive treatment of dynamical friction. Our model reproduces well the metallicity distribution measured for Galactic GCs, even though we predict systematically younger GCs than observed. We argue that this adds further evidence for an anomalously early formation of the stars in our Galaxy.

Characterisation of coherent ultrasonic nonlinear imaging

Nonlinear ultrasonic imaging methods for non-destructive testing have shown sensitivity to early damage formation. Among those, the Fundamental wave Amplitude Difference (FAD) technique has been proposed in the literature as a nonlinearity mapping method for defect visualisation. It does so by calculating the residual between a low and high nonlinearity image, which is achieved by some modulation of the focal spot amplitude. This is realised either through different input voltages or alternating the element-wise firing scheme. This paper assesses the sensitivity of FAD through different techniques used for the generation of the low nonlinearity images, using both theoretical and experimental approaches. These techniques include (1) Different-Voltage FAD (DV-FAD); (2) Odd-Even FAD (OE-FAD) and; (3) Parallel–Sequential FAD (PS-FAD). Formulae are derived that allow the different firing sequences and image corrections to be compared. The FAD techniques are then experimentally evaluated against the theory, showing a 50% amplitude gain at the crack tip when comparing PS-FAD to OE-FAD and DV-FAD. Additionally, the instrument behaviour is assessed by considering the image correction required to improve the image contrast for the visualisation of the crack tip. Finally, it is shown that all FAD techniques are equivalent in terms of nonlinear detection but additional work is required in comparing the performance of other array controllers when using FAD.

Surface blistering and D desorption in high-energy-rate forging W, W-Y2O3, W-TiC exposed to deuterium plasma

Pure tungsten (W) and two representative W alloys of W-1 wt.%Y2O3 and W-0.5 wt.%TiC were subjected to deuterium (D) plasma exposure at a fluence up to 1 × 1026 D/m2 at 400 K to evaluate their surface blistering and D desorption behaviors. Thermal desorption spectroscopy (TDS) results revealed that high-temperature desorption peaks (> 650 K) dominated in HERF-W, whereas the two W alloys featured higher intensities of low-temperature D desorption peaks (< 650 K). Even at a low D implantation fluence of 5 × 1023 D/m2, extensive blisters were evident on the surface of pure W, while no discernible blisters were detected on the surface of W-1 wt.%Y2O3 and W-0.5 wt.%TiC, even with a fluence exceeding 2 × 1025 D/m2. Microstructure analysis indicated that the relatively large grain size and limited intrinsic defects in HERF-W were the primary reasons for the early formation of D-induced blisters and subsequent high-temperature desorption of these trapped D, compared to those of two other W alloys. A focus ion beam (FIB)-SEM technique was employed to explore the mechanisms of blistering. Results revealed that the cavities beneath blisters were primarily located along grain boundaries, and coarse blisters were formed by the merging of several small ones. This work provides insight into the relationships among material microstructures, D-induced blistering and D desorption in W-based materials, thus offering valuable guidance for the design of W materials with high resistance to D-induced damages.

Nothochrysinae (Neuroptera: Chrysopidae) from the early Eocene Fur Formation, Denmark, with description of a new genus

Furochrysa alisae gen et sp. nov. is described, and Stephenbrooksia multifurcata Willmann, 1993 and Danochrysa madseni Willmann, 1993 are re-described based on their holotypes and additional specimens from the early Eocene Fur Formation of Denmark. The very long crossvein 1icu between CuA and CuP in the hind wing distinguishes Furochrysa gen. nov. from all other Nothochrysinae. The hind wing venation of the holotype of S. multifurcata is strongly aberrant; in particular, its MA is deeply forked proximad the origin of RP, while it is not forked proximad the pseudocubitus in other Chrysopidae. The forewing venation of the three examined specimens of D. madseni show variability in the branching of the anterior branch of CuP and A2. The chrysopid assemblage of the early Eocene Fur Formation strongly differs from that of the late Paleogene (late Eocene/Oligocene) of Europe, while the nothochrysines of the early and late Paleogene of North America do not especially differ.