Complex Nuclei Research Articles

Biomechanical evaluation of different semi-rigid junctional fixation techniques using finite element analysis

BackgroundProximal junctional failure is a common complication attributed to the rigidity of long pedicle screw fixation constructs used for surgical correction of adult spinal deformity. Semi-rigid junctional fixation achieves a gradual transition in range of motion at the ends of spinal instrumentation, which could lead to reduced junctional stresses, and ultimately reduce the incidence of proximal junctional failure. This study investigates the biomechanical effect of different semi-rigid junctional fixation techniques in a T8-L3 finite element spine segment model. MethodsFirst, degeneration of the intervertebral disc was successfully implemented by altering the height. Second, transverse process hooks, one- and two-level clamped tapes, and one- and two-level knotted tapes instrumented proximally to three-level pedicle screw fixation were validated against ex vivo range of motion data of a previous study. Finally, the posterior ligament complex forces and nucleus pulposus stresses were quantified. FindingsSimulated range of motions demonstrated the fidelity of the general model and modelling of semi-rigid junctional fixation techniques. All semi-rigid junctional fixation techniques reduced the posterior ligament complex forces at the junctional zone compared to pedicle screw fixation. Transverse process hooks and knotted tapes reduced nucleus pulposus stresses, whereas clamped tapes increased nucleus pulposus stresses at the junctional zone. InterpretationThe relationship between the range of motion transition and the reductions in posterior ligament complex and nucleus pulposus stresses was complex and dependent on the fixation techniques. Clinical trials are required to compare the effectiveness of semi-rigid junctional fixation techniques in terms of reducing proximal junctional failure incidence rates.

Block symmetries in graph coloring reconfiguration systems

In this paper, we study reconfiguration systems for proper graph colorings modified by single-vertex recolorings. Applying a general construction of Ghrist and Peterson [15] to the graph coloring problem, we consider cubical complexes in which cubes represent recolorings of independent sets of vertices. For any choice of base graph and number of colors, the 0-skeleton of the associated coloring state complex is the set of proper colorings, and the 1-skeleton is the transition graph.Appealing to symmetries induced by color permutation, we give two main results regarding the organization of the biconnected components (blocks) of coloring transition graphs and the colorings within those blocks. First, the 1-skeleton of any connected coloring state complex has a unique block whose vertex set is the union of entire classes of isomorphic colorings. We call this block the nucleus. Second, the nucleus of the state complex of any non-empty graph contains a non-trivial cycle. This implies that although the state complex for any reconfiguration system is locally CAT(0) [15], only the very simplest coloring state complexes are globally CAT(0).

Identifying reproducible resting state networks and functional connectivity alterations following chronic restraint stress in anaesthetized rats.

Resting-state functional MRI (rs-fMRI) in rodent models have the potential to bridge invasive experiments and observational human studies, increasing our understanding of functional alterations in the brains of patients with depression. A major limitation in current rodent rs-fMRI studies is that there has been no consensus on healthy baseline resting-state networks (RSNs) that are reproducible in rodents. Therefore, the present study aimed to construct reproducible RSNs in a large dataset of healthy rats and then evaluate functional connectivity changes within and between these RSNs following a chronic restraint stress (CRS) model within the same animals. A combined MRI dataset of 109 Sprague Dawley rats at baseline and after two weeks of CRS, collected during four separate experiments conducted by our lab in 2019 and 2020, was re-analysed. The mICA and gRAICAR toolbox were first applied to detect optimal and reproducible ICA components and then a hierarchical clustering algorithm (FSLNets) was applied to construct reproducible RSNs. Ridge-regularized partial correlation (FSLNets) was used to evaluate the changes in the direct connection between and within identified networks in the same animals following CRS. Four large-scale networks in anesthetised rats were identified: the DMN-like, spatial attention-limbic, corpus striatum, and autonomic network, which are homologous across species. CRS decreased the anticorrelation between DMN-like and autonomic network. CRS decreased the correlation between amygdala and a functional complex (nucleus accumbens and ventral pallidum) in the right hemisphere within the corpus striatum network. However, a high individual variability in the functional connectivity before and after CRS within RSNs was observed. The functional connectivity changes detected in rodents following CRS differ from reported functional connectivity alterations in patients with depression. A simple interpretation of this difference is that the rodent response to CRS does not reflect the complexity of depression as it is experienced by humans. Nonetheless, the high inter-subject variability of functional connectivity within networks suggests that rats demonstrate different neural phenotypes, like humans. Therefore, future efforts in classifying neural phenotypes in rodents might improve the sensitivity and translational impact of models used to address aetiology and treatment of psychiatric conditions including depression.

Characterization of three cholinergic inputs to the cochlear nucleus

Acetylcholine modulates responses throughout the auditory system, including at the earliest brain level, the cochlear nucleus (CN). Previous studies have shown multiple sources of cholinergic input to the CN but information about their relative contributions and the distribution of inputs from each source is lacking. Here, we used staining for cholinergic axons and boutons, retrograde tract tracing, and acetylcholine-selective anterograde tracing to characterize three sources of acetylcholine input to the CN in mice. Staining for cholinergic axons showed heavy cholinergic inputs to granule cell areas and the dorsal CN with lighter input to the ventral CN. Retrograde tract tracing revealed that cholinergic cells from the superior olivary complex, pontomesencephalic tegmentum, and lateral paragigantocellular nucleus send projections to the CN. When we selectively labeled cholinergic axons from each source to the CN, we found surprising similarities in their terminal distributions, with patterns that were overlapping rather than complementary. Each source heavily targeted granule cell areas and the dorsal CN (especially the deep dorsal CN) and sent light input into the ventral CN. Our results demonstrate convergence of cholinergic inputs from multiple sources in most regions of the CN and raise the possibility of convergence onto single CN cells. Linking sources of acetylcholine and their patterns of activity to modulation of specific cell types in the CN will be an important next step in understanding cholinergic modulation of early auditory processing.

MIU-Net: MIX-Attention and Inception U-Net for Histopathology Image Nuclei Segmentation

In the medical field, hematoxylin and eosin (H&E)-stained histopathology images of cell nuclei analysis represent an important measure for cancer diagnosis. The most valuable aspect of the nuclei analysis is the segmentation of the different nuclei morphologies of different organs and subsequent diagnosis of the type and severity of the disease based on pathology. In recent years, deep learning techniques have been widely used in digital histopathology analysis. Automated nuclear segmentation technology enables the rapid and efficient segmentation of tens of thousands of complex and variable nuclei in histopathology images. However, a challenging problem during nuclei segmentation is the blocking of cell nuclei, overlapping, and background complexity of the tissue fraction. To address this challenge, we present MIU-net, an efficient deep learning network structure for the nuclei segmentation of histopathology images. Our proposed structure includes two blocks with modified inception module and attention module. The advantage of the modified inception module is to balance the computation and network performance of the deeper layers of the network, combined with the convolutional layer using different sizes of kernels to learn effective features in a fast and efficient manner to complete kernel segmentation. The attention module allows us to extract small and fine irregular boundary features from the images, which can better segment cancer cells that appear disorganized and fragmented. We test our methodology on public kumar datasets and achieve the highest AUC score of 0.92. The experimental results show that the proposed method achieves better performance than other state-of-the-art methods.

Interhemispheric competition during sleep

Our understanding of the functions and mechanisms of sleep remains incomplete, reflecting their increasingly evident complexity1–3. Likewise, studies of interhemispheric coordination during sleep4–6 are often hard to connect precisely to known sleep circuits and mechanisms. Here, by recording from the claustra of sleeping bearded dragons (Pogona vitticeps), we show that, although the onsets and offsets of Pogona rapid-eye-movement (REMP) and slow-wave sleep are coordinated bilaterally, these two sleep states differ markedly in their inter-claustral coordination. During slow-wave sleep, the claustra produce sharp-wave ripples independently of one another, showing no coordination. By contrast, during REMP sleep, the potentials produced by the two claustra are precisely coordinated in amplitude and time. These signals, however, are not synchronous: one side leads the other by about 20 ms, with the leading side switching typically once per REMP episode or in between successive episodes. The leading claustrum expresses the stronger activity, suggesting bilateral competition. This competition does not occur directly between the two claustra or telencephalic hemispheres. Rather, it occurs in the midbrain and depends on the integrity of a GABAergic (γ-aminobutyric-acid-producing) nucleus of the isthmic complex, which exists in all vertebrates and is known in birds to underlie bottom-up attention and gaze control. These results reveal that a winner-take-all-type competition exists between the two sides of the brain of Pogona, which originates in the midbrain and has precise consequences for claustrum activity and coordination during REMP sleep.

Morphology of kisspeptin-producing nuclei in the rat hypothalamus

ВACKGROUND: The article is devoted to the stereo-morphological analysis of the nuclei of the hypothalamus, synthesizing proteins of the kisspeptin family, regulating sexual differentiation various parts of the extended kisspeptin-producing nuclei of the hypothalamus and the features of their asymmetry in mature rats. The morphology of various parts of extended kisspeptin-producing nuclei of the hypothalamus remains poorly understood, which significantly complicates the choice of their reference zone, from which planning and implementation of morphological studies should begin, related to the evaluation of the effectiveness of therapeutic correction of various forms of hypogonadism.
 AIM: Determination of the main source of regulatory peptides of the kisspeptin family based on the analysis of the number, area of neuron bodies and volumetric characteristics of the kisspeptin-producing nuclei of the hypothalamus.
 MATERIALS AND METHODS: We studied 50 frontal paraffin sections of KPNs of 8 intact sexually mature male rats obtained as a result of a standard technique for their preparation and staining by the Nissl method. As a result, we carried out volumetric reconstruction of the largest nucleus of the arcuate complex the medial arcuate nucleus and the large periventricular nucleus, after which the number and area of neurosecretory cell bodies were determined in 5 frontal planes of these nuclei. To determine the proportion of kisspeptin-producing neurons in the total number of neurons in the kisspeptin-producing nuclei of the hypothalamus, we also performed the subsequent quantitative and morphometric characterization of their kisspeptin-producing neurons (after immunohistochemical staining, the identification of kisspeptin-kisspeptin granules. Statistical data processing was performed using the GraphPad PRISM 6.0 program, determining and lower quartiles. Differences were considered significant at p 0.01.
 RESULTS: Subdivisions of the nuclei, which are the main source of these regulatory proteins, have been identified. The caudal part of the medial arcuate nucleus (at the level of bregma 3.6 mm) and the anterior part of the periventricular nucleus (at the level of bregma 0.2 mm) are subdivisions of the corresponding kisspeptin-producing nuclei of the hypothalamus of the kisspeptin-producing nuclei of the hypothalamus, containing the largest number of neurosecretory cells and the bodies of their largest largest area. The number and area of neurons in the left-sided and right-sided parts of the hypothalamic kisspeptin-producing nuclei of the hypothalamus did not differ significantly. In this regard, the listed left-sided and right-sided subdivisions of the kisspeptin-producing kisspeptin-producing nuclei of the hypothalamus of the were proposed as standards for their subsequent morphological studies, which are important for assessing the effectiveness of therapeutic correction of various forms of hypogonadism.
 CONCLUSIONS: The left-sided and right-sided caudal parts of the medial arcuate hypothalamic nucleus and the anterior parts of the periventricular hypothalamic nucleus are proposed as a reference for their subsequent morphological studies related to the evaluation of the effectiveness of therapeutic correction of various forms of hypogonadism. as the main sources of regulatory proteins of the kisspeptin family.

Phosphorescent cyclometalated iridium(III) complexes with mono‐, di‐, and tetranuclear as two channel probes to light up the nuclei of living cells

By altering the reaction ratio of precursor Ir2(ppy)4Cl2 and bridging ligand of 4,4‐bipyridine (bpy), a series of phosphorescent cyclometalated iridium(III) complexes of mono‐, di‐, and tetranuclear have been successfully obtained and characterized for the first time. The dissociation of bpy ligand can be accelerated by light irradiation or placing these complexes in glutathione (GSH) abundant aqueous solution, bpy releasing rate follows the order Ir1 > Ir2 > Ir3 > Ir4, and with an addition of histidine, a significant blue shift from orange to green phosphorescence was observed. Herein, the cellular dissociation of bpy can be monitored by an orange‐to‐green phosphorescent blue shift, and nuclei of living cells can be lighted up by a set of probes with two phosphorescent channels, and subsequent cellular uptake translocation from cytoplasm to nucleus of Ir complexes could be observed by confocal imaging within 4 h. Besides, the changes of cellular phosphorescence intensity in two fluorescent channels recorded by flow cytometry could reflect different speed of bpy release in human normal and cancer cells. Besides, Ir1–4 exert significant anticancer effect in the dark with low photocytotoxicity, by effectively inducing reactive oxygen species generation, mitochondrial membrane potential depletion, and interacting with biomolecules, and they eventually induce late apoptosis of Hela cell.

Precision Møller polarimetry for PREX-2 and CREX

The PREX-2 and CREX experiments in Hall A at Jefferson Lab are precision measurements of parity violating elastic electron scattering from complex nuclei. One requirement was that the incident electron beam polarization, typically ≈90%, be known with 1% precision. We commissioned and operated a Møller polarimeter on the beam line that exceeds this requirement, achieving a precision of 0.89% for PREX-2, and 0.85% for CREX. The uncertainty is purely systematic, accumulated from several different sources, but dominated by our knowledge of the target polarization. Our analysis also demonstrates the need for accurate atomic wave functions in order to correct for the Levchuk Effect. We describe the details of the polarimeter operation and analysis, as well as (for CREX) a comparison to results from a different polarimeter based on Compton scattering.

Structure, function and genoarchitectonics of the Central nucleus of the Brain’s Amygdala

The review presents the latest literature describing the Central nucleus of the Amygdala complex of the brain (CE), which is an important link in the Central autonomic nervous network. It appears in the early stages of the evolution of the telencephalon. This determines its solid phylogenetic age and explains the heteromorphy, which is manifested by the presence of a number of subnucleus: medial, intermediate, lateral and latero-capsular. The article provides information about the features of cytoarchitectonics, neural organization of subnucleus and neuropeptides. Among the latter, special attention is paid to vasopressin and oxytocin in connection with the identified new way of innervation of the amygdala complex, which has at least two origins: 1. arising from a small population of neurons localized in the intra-amygdalar portion of the bed nucleus of the stria terminalis, and 2.originating from hypothalamic neurosecretory nuclei. Afferent and efferent connections of CE are characterized. A large number of studies define the medial subnucleus as the center of integration of incoming information to the CE and the main channel for its exit from CE. At the same time, the main point where efferent connections of CE follow is the centers of the brain stem that control cardiovascular, respiratory, metabolic and motor functions. Information is provided about the main functions, including the regulation of various forms of social behavior, eating behavior, and involvement in functional reinforcement systems. The results of genetic studies indicate that CE is a derivative of the striatal division of the lateral ganglionic eminence, in the formation of which the expression of the Dlx5 and Lmo4 genes.

Organisation of enkephalin inputs and outputs of the central nucleus of the amygdala in mice

The central nucleus of the amygdala (CeA) is a key hub integrating sensory inputs and modulating behavioural outputs. The CeA is a complex structure with discrete subdivisions, high peptidergic heterogeneity and broad CNS afferent and efferent projections. While several neuropeptide systems within the CeA have been examined in detail, less is known about CeA preproenkephalin (ppENK) cells. Here, we used a recently developed transgenic Penk-Cre mouse line to advance our understanding of the efferent and afferent connectivity of ppENK in the CeA. First, to determine the fidelity of Cre expression in Penk-Cre transgenic mice, we conducted RNAscope in the CeA of Penk-Cre mice. Our analysis revealed that 96.6 % of CeA Cre+ neurons co-expressed pENK mRNA, and 99.7 % of CeA pENK+ neurons co-expressed Cre mRNA, indicating faithful recapitulation of Cre expression in CeA ppENK-expressing cells, supporting the fidelity of the Penk-Cre reporter mouse. Anterograde tracing of CeAPenk cells showed strong efferent projections to the extended amygdala, midbrain and hindbrain PBN and NTS. Retrograde tracing of Penk afferents to the CeA were more restricted, with primary innervation originating within the amygdala complex and bed nucleus of the stria terminalis, and minor innervation from the parabrachial nucleus and nucleus of the solitary tract. Together, our data provide a comprehensive map of ENKergic efferent and afferent connectivity of the CeA in Penk-Cre mice. Further, we highlight both the utility and limitations of the Penk-Cre mice to study the function of CeA, PBN and NTS ppENK cells.

Exploring the anti-influenza virus activity of novel triptolide derivatives targeting nucleoproteins

Triptolide (TP) is a major active compound derived from the traditional Chinese medicine Tripterygium wilfordii. TP has been reported to inhibit the infection of HIV and a few other viruses. However, the antiviral spectrum and the underlying mechanisms of TP are incompletely defined. TP derivatives were designed, synthesized, and evaluated for anti-influenza activity against the influenza A virus in this study. All of them exhibited activities against oseltamivir sensitive influenza A/WSN/33 virus (H1N1) and oseltamivir resistant influenza A/PR/8/33 virus (H1N1) with low cytotoxicity in vitro. In our present study, TP derivatives probably suppressed influenza virus replication through inhibiting ribonucleoprotein complex nucleus export of influenza A virus by binding with viral nucleoprotein. Moreover, TP derivatives downregulated influenza A virus-induced macrophage cytokine storm in a dose-dependent manner, through inhibiting nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) and NOD-like receptor protein 3 (NLRP3) inflammasome signaling. Taken together, TP derivatives suppressed influenza A virus replication by directly targeting NP and regulating innate immune responses induced by influenza A virus infection, which suggested that TP derivatives might be prospective candidates for potent antivirals.

Burkina Faso through Its Traditional Architecture: A Century of Research on Built Vernacular Heritage

The study of traditional habitats aims to recognise their values and preserve them within the necessary transformations of societies. In the context of Burkina Faso, the great variety of issues related to habitat together with the cultural richness of the country, resulted in a complex nucleus of knowledge, the unity of which had not been fully considered. With the objective of providing an integrated overview and identifying thematic trends of current relevance, the literature review involved the collection, comparison, and synthesis of works of different origin, scale, discipline, theme, and intention. As well as offering an orderly compilation, the analysis traces the history of the existing literature, revealing how its evolution mirrored the progress in vernacular architecture studies in international terms and adopted an increasingly practical approach. Furthermore, the review demonstrates the widespread academic and institutional interest in linking the development of the country to its cultural heritage, and the valuable documentation work resulting from this interest. Finally, a reflection is raised on the evolution of knowledge, its aspirations, potential impact, and usefulness, which could be of use also in other contexts.

The effects of prenatal bisphenol A exposure on brain volume of children and young mice

Bisphenol A (BPA) is a synthetic chemical used for the manufacturing of plastics, epoxy resin, and many personal care products. This ubiquitous endocrine disruptor is detectable in the urine of over 80% of North Americans. Although adverse neurodevelopmental outcomes have been observed in children with high gestational exposure to BPA, the effects of prenatal BPA on brain structure remain unclear. Here, using magnetic resonance imaging (MRI), we studied the associations of maternal BPA exposure with children's brain structure, as well as the impact of comparable BPA levels in a mouse model. Our human data showed that most maternal BPA exposure effects on brain volumes were small, with the largest effects observed in the opercular region of the inferior frontal gyrus (ρ = −0.2754), superior occipital gyrus (ρ = −0.2556), and postcentral gyrus (ρ = 0.2384). In mice, gestational exposure to an equivalent level of BPA (2.25 μg BPA/kg bw/day) induced structural alterations in brain regions including the superior olivary complex (SOC) and bed nucleus of stria terminalis (BNST) with larger effect sizes (1.07≤ Cohens d ≤ 1.53). Human (n = 87) and rodent (n = 8 each group) sample sizes, while small, are considered adequate to perform the primary endpoint analysis. Combined, these human and mouse data suggest that gestational exposure to low levels of BPA may have some impacts on the developing brain at the resolution of MRI.

Evolution of the statistical disintegration of finite nuclei toward high energy

We develop a statistical approach for the description of complex nuclei formation from dynamically produced baryons in high energy heavy-ion reactions. We consider a finite highly-excited expanding nuclear system formed after central nucleus-nucleus collisions. This system is sub-divided into primary equilibrated nucleon clusters. The final nuclei are produced after the decay of these excited clusters. By the successful comparison with the FOPI experimental data we prove the possibility of such a local equilibrium in nuclear matter with the temperature corresponding to the phase coexistence region. The regularities obtained in this new nuclei production mechanism are shown.

A Delay Efficient Hybrid Parallel Prefix Variable Latency CSKA Based Multi-Operand Adder with Optimized 5:2 Compressor and Skip Logic

In this paper, a delay efficient multi-operand adder (MOA) is introduced by considering the compression logic and variable latency carry skip adder (VL-CSKA). Here, an optimized 5:2 compressor is initially used to increase the speed of MOA by reducing the number of operands before giving as input to VL-CSKA. Also, the VL-CSKA is modified by replacing the carry propagation with complementary complex gates (CCG) and nucleus stage with improved parallel prefix structure for increasing the speed with fewer components. The delay, area, power, and logic depth of the proposed hybrid parallel prefix VL-CSKA (HPP-VL-CSKA) is also reduced by modifying the group Propagate-Generate (PG) logic in the parallel prefix structure. Also, a new circuit for XOR/XNOR gate is used for the reduction of the delay and power consumption significantly. The synthesis result shows that the suggested adder design overtakes the existing adders by consuming only 5953 area, 1.763power, 1.251fJ and 3516.63 ADP for 20 number of operands, each with 32 bit inputs.

Effect of Al content on the δ→γ transformation and M23C6 precipitation behavior in 18Cr-xAl-Si ferritic heat-resistant stainless steel during solidification process

Aimed at clarifying δ→γ transformation and M23C6 precipitation behavior in18Cr-xAl-Si (x = 0, 0.43wt.%, 0.91wt.% and 1.82wt.%) ferritic heat-resistant stainless steel (FHSS), high temperature confocal scanning laser microscopy (CSLM) was used for in-situ observation during solidification. The results demonstrated that increasing of Al content reduced the nucleation temperature of δ-ferrite, and at the same time reduced the free energy difference between δ-ferrite and γ-austenite, which increased the difficulty of δ→γ transformation, in turn reduced the temperature of δ→γ transformation. The γ-austenite preferentially precipitated at the δ-ferrite phase boundaries and gradually along the sides of the δ-ferrite phase boundaries as the temperature decreased, and part of the martensite transformed inside the γ-austenite phases. M23C6 carbides mainly precipitated at the phase boundaries between δ-ferrite and γ-austenite/martensite. With the increase of Al content, the amount of γ-austenite/martensite and M23C6 carbides decreased. In addition, the solidification mechanism of the complex nucleus was also discussed.

Multi-reference many-body perturbation theory for nuclei

In spite of missing dynamical correlations, the projected generator coordinate method (PGCM) was recently shown to be a suitable method to tackle the low-lying spectroscopy of complex nuclei. Still, describing absolute binding energies and reaching high accuracy eventually requires the inclusion of dynamical correlations on top of the PGCM. In this context, the present work discusses the first realistic results of a novel multi-reference perturbation theory (PGCM-PT) that can do so within a symmetry-conserving scheme for both ground and low-lying excited states. First, proof-of-principle calculations in a small (\(e_{\mathrm {max}}=4\)) model space demonstrate that exact binding energies of closed- (\({}^{16}\mathrm {O}\)) and open-shell (\({}^{18}\mathrm {O}\), \({}^{20}\mathrm {Ne}\)) nuclei are reproduced within 0.5–\(1.5\%\) at second order, i.e. through PGCM-PT(2). Moreover, profiting from the pre-processing of the Hamiltonian via multi-reference in-medium similarity renormalization group transformations, PGCM-PT(2) can reach converged values within smaller model spaces than with an unevolved Hamiltonian. Doing so, dynamical correlations captured by PGCM-PT(2) are shown to bring essential corrections to low-lying excitation energies that become too dilated at leading order, i.e., at the strict PGCM level. The present work is laying the foundations for a better understanding of the optimal way to grasp static and dynamical correlations in a consistent fashion, with the aim of accurately describing ground and excited states of complex nuclei via ab initio many-body methods.

Multi-reference many-body perturbation theory for nuclei

The neon isotopic chain displays a rich phenomenology, ranging from clustering in the ground-state of the self-conjugate doubly open-shell stable $$^{20}$$ Ne isotope to the physics of the island of inversion around the neutron-rich $$^{30}$$ Ne isotope. This second (i.e. Paper II) of the present series proposes an extensive ab initio study of neon isotopes based on two complementary many-body methods, i.e. the quasi-exact in-medium no-core shell model (IM-NCSM) and the projected generator coordinate method (PGCM) that is ideally suited to capturing strong static correlations associated with shape deformation and fluctuations. Calculations employ a state-of-the-art generation of chiral effective field theory Hamiltonians and evaluate the associated systematic uncertainties. In spite of missing so-called dynamical correlations, which can be added via the multi-reference perturbation theory proposed in the first paper (i.e. Paper I) of the present series [1], the PGCM is shown to be a suitable method to tackle the low-lying spectroscopy of complex nuclei. Still, describing the physics of the island of inversion constitutes a challenge that seems to require the inclusion of dynamical correlations. This is addressed in the third paper (i.e. Paper III) of the present series [2].

Influence of cooling rate on δ-ferrite/γ-austenite formation and precipitation behavior of 18Cr–Al–Si ferritic heat-resistant stainless steel

The δ-ferrite/γ-austenite formation and precipitation behavior of 18Cr–Al–Si FHSS (ferritic heat-resistant stainless steel) during solidification has been investigated by a high temperature confocal scanning laser microscopy (CSLM) at the cooling rates from 5 °C min−1 to 100 °C min−1. The results have demonstrated that the increase of cooling rate will decrease nucleation temperature of δ-ferrite phase, which will affect δ-ferrite/γ-austenite formation process, and the δ→γ transformation process all occurred at the texted cooling rates. The γ-austenite phase first precipitated at δ-ferrite phase boundaries and then appeared within δ-ferrite phase, and in the subsequent cooling process, part of the γ-austenite begins to transform into martensite. The content of γ-austenite/martensite phase and M23C6 carbides increased with the increment of cooling rate. In addition, the solidification mechanism of the complex nucleus at the cooling rates of 5 °C min−1 and 100 °C min−1 were also discussed.