Axial Domain Research Articles

P57 Cross-sectional application of the dermatologist-centred screening tool, looking for axial psoriatic arthritis in patients with severe plaque psoriasis

Abstract Psoriasis is a chronic, inflammatory and immune-mediated systemic disease that primarily affects the skin and joints. In ∼70% of cases, the skin disease precedes joint involvement, and it is estimated that approximately one-third of patients with psoriatic disease will develop psoriatic arthritis (PsA) over the course of their disease. Researchers often seek to establish good screening tools or even biomarkers that can help the clinical dermatologist in this assessment, improving the window of opportunity for action. Most of the validated tools, such as PEST and PASE, despite their excellent performance, do not consider the axial domain of PsA. We conducted a cross-sectional study on our cohort of severe psoriasis patients from our outpatient clinic, applying the dermatologist-centred screening (DCS) questionnaire. PsA was defined by CASPAR criteria. Statistical analysis was performed in SPSS 20.0. The study underwent ethical review and was approved: average age of 50.84 years, with a slight predominance of females (53.2%). The average duration of the disease was 15.89 years. Mean PASI and body surface area (BSA) were, respectively, 16.65 and 20.88%. Hundred and fifty-eight patients were studied: average age of 50.84 years, with a slight predominance of females (53.2%). The average duration of the disease was 15.89 years. Mean PASI and BSA were, respectively, 16.65 and 20.88%. Fifty of the 158 patients were diagnosed with PsA (31.6%). In the sample, 35 patients had positive DCS. Of these 35, in fact, 25 (71.4%) had PsA. Having positive DCS implies a prevalence at least three times higher than having PsA (prevalence ratio: 3.254, P < 0.0001, 95% confidence interval = 2.195–4.824). Among the 25 with positive DCS, 10 patients had low back pain at the end of the night, sometimes even being woken up by the pain; maintaining it during the morning, associated with stiffness for at least 30 min; in addition to relief with movement and stretching. Of these 10, 7 (14% of patients with PsA and 28% of all with positive DCS) had a confirmed diagnosis of axial PsA, supported by evaluation by a board-certified rheumatologist, in addition to complementary exams (all with positive magnetic resonance imaging showing sacroiliitis). The ATTRACT study studied 365 patients; selecting through DCS 124. Of these, 36 (29%) confirmed a diagnosis of Axial PsA and 21 (16.9%) had peripheral PsA, without axial involvement. DCS appears to be a practical, quick and easy tool to perform in clinical practice, correctly selecting patients for better evaluation by a rheumatologist, probably contributing to a better diagnosis. The limitations of this work are the cross-sectional design and small sample.

P171 Bimekizumab impact on core group for research and assessment of psoriasis and psoriatic arthritis domains for patients with psoriatic arthritis: 52-week results from four phase 3 studies

Abstract Background/Aims The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (PsA; GRAPPA) domainbased treatment recommendations for PsA focus on six domains: peripheral arthritis, axial disease, enthesitis, dactylitis, skin psoriasis, and nail psoriasis, and PsA-related conditions: uveitis and IBD. Bimekizumab (BKZ), a monoclonal IgG1 antibody that selectively inhibits IL17F in addition to IL17A, has superior clinical efficacy vs placebo (PBO) to Week (Wk)16 in phase 3 clinical trials of PsA patients. In patients with psoriasis, superior skin domain efficacy was demonstrated versus secukinumab (IL-17A inhibitor), ustekinumab (IL-12/23 inhibitor), and adalimumab (TNF inhibitor [TNFi]). Methods Included patients received subcutaneous BKZ 160 mg or PBO every 4-wks (Q4W) in BE OPTIMAL (NCT03895203; biologic disease-modifying antirheumatic drugs [bDMARD]naïve patients with PsA), BE COMPLETE (NCT03896581; patients with PsA who were TNFiinadequate responders [TNFiIR]), BE MOBILE 1 (NCT03928704; nonradiographic axial spondyloarthritis [nr-axSpA]) and BE MOBILE 2 (NCT03928743; radiographic [r-]axSpA [i.e. ankylosing spondylitis]). BE OPTIMAL included a reference arm (adalimumab 40 mg Q2W) to Wk52; data not shown. From Wk16, all PBO-randomised patients received BKZ 160 mg Q4W to Wk52 (PBO/BKZ). Wk16 completers from BE COMPLETE entered BE VITAL (NCT04009499; openlabel extension). Outcomes are reported by GRAPPA domain as change from baseline and/or responder rate. Missing data were imputed using non-responder (binary) or multiple (continuous) imputation. Results Wk52 completion was high (BE OPTIMAL: 770/852 [90.4%], BE COMPLETE: 347/400 [86.8%], BE MOBILE 1: 220/254 [86.6%], BE MOBILE 2: 298/332 [89.8%]). Baseline demographics and disease characteristics were previously reported. Across all GRAPPA domains, improvements from Wk16 were sustained at Wk52 in BKZ-treated patients across all studies. Individual domain responses were generally consistent between bDMARD naïve and TNFi-IR patients; results from BE MOBILE 1 and 2 demonstrated BKZ efficacy in patients with axSpA (Table). Responses were generally consistent between BKZ and PBO/BKZ patients at Wk52. To Wk52, there were low rates of adjudicated IBD (2 [0.2%] in BE OPTIMAL) and no instances of uveitis. Conclusion Treatment with BKZ resulted in robust and sustained improvements across GRAPPA domains to Wk52 for both bDMARD naïve and TNFi-IR patients with PsA; results from patients with axSpA support efficacy in the axial domain. Disclosure J.F. Merola: Consultancies; AbbVie, Amgen, Biogen, BMS, Dermavant, Eli Lilly, Janssen, LEO Pharma, Pfizer, Novartis, Regeneron, Sanofi, Sun Pharma, and UCB Pharma. Other; Investigator for AbbVie, Amgen, Biogen, BMS, Dermavant, Eli Lilly, Janssen, LEO Pharma, Pfizer, Novartis, Regeneron, Sanofi, Sun Pharma, and UCB Pharma. P.J. Mease: Consultancies; AbbVie, Acelyrin, Aclaris, Amgen, BMS, Boehringer Ingelheim, Eli Lilly, Galapagos, Gilead, GSK, Janssen, Moonlake Pharma, Novartis, Pfizer, Sun Pharma and UCB Pharma. Member of speakers’ bureau; AbbVie, Amgen, Eli Lilly, Janssen, Novartis, Pfizer and UCB Pharma. Grants/research support; AbbVie, Acelyrin, Amgen, BMS, Eli Lilly, Gilead, Janssen, Novartis, Pfizer, Sun Pharma and UCB Pharma. A. Deodhar: Consultancies; AbbVie, BMS, Eli Lilly, Janssen, MoonLake, Novartis, Pfizer, UCB Pharma. Member of speakers’ bureau; Janssen, Novartis, Pfizer. Grants/research support; AbbVie, BMS, Celgene, Eli Lilly, MoonLake, Novartis, Pfizer, UCB Pharma. B. Ink: Shareholder/stock ownership; AbbVie, GSK, UCB Pharma. Other; Employee of UCB Pharma. C. Fleurinck: Other; Employee of UCB Pharma. R. Bajracharya: Shareholder/stock ownership; UCB Pharma. Other; Employee of UCB Pharma. J. Coarse: Shareholder/stock ownership; UCB Pharma. Other; Employee of UCB Pharma. L.C. Coates: Consultancies; AbbVie, Amgen, BMS, Boehringer Ingelheim, Celgene, Domain, Eli Lilly, Galapagos, Gilead, Janssen, Moonlake Pharma, Novartis, Pfizer, UCB Pharma. Member of speakers’ bureau; AbbVie, Amgen, Biogen, Celgene, Eli Lilly, Galapagos, Gilead, GSK, Janssen, medac, Novartis, Pfizer, UCB Pharma. Grants/research support; AbbVie, Amgen, Celgene, Eli Lilly, Gilead, Janssen, Novartis, Pfizer, UCB Pharma.

Association of clinical response criteria and disease activity levels with axial spondyloarthritis core domains: results from two phase 3 randomised studies, BE MOBILE 1 and 2

ObjectiveTo assess how achievement of increasingly stringent clinical response criteria and disease activity states at week 52 translate into changes in core domains in patients with non-radiographic (nr-) and radiographic...

Risk Factors Associated with Difficult-to-treat (D2T) Psoriatic Arthritis - A One-year Analysis from the APLAR SpA Registry

Background: Despite the widespread advocacy of the treat-to-target(T2T) strategy for managing psoriatic arthritis (PsA), a significant number of patients fail to achieve minimal disease activity (MDA) even with advanced therapies. While a universal definition of difficult-to-treat(D2T) PsA is absent, investigating the heterogeneity of D2T PsA within a real-life T2T-cohort can offer valuable insights into comprehending this concept. Methods: This analysis included the first 111 PsA patients enrolled in the APLAR SpA registry who underwent 1-year T2T management. They were recruited from 6 Asia-Pacific regions. D2T was defined as the failure to achieve MDA despite receiving [Formula: see text]1 conventional synthetic disease-modifying anti-rheumatic drugs(csDMARDs) and [Formula: see text]1 biologic/targeted synthetic DMARDs(b/tsDMARDs) over 6-months. Results: A total of 111 patients (mean age: 48± 13 years, 59 [53%] male, mean disease duration: 5.3± 7.3 years) were included. At baseline, the patients exhibited moderate disease activity, with only 35% achieving MDA. After 1-year, a significant improvement in Disease Activity in Psoriatic Arthritis (DAPSA) was observed (16.3± 14.0 at baseline vs 10.1± 9.7 at 1-year, p<0.001), with 56% of patients achieving MDA. At one-year, 17(15%) patients fulfilled the definition of D2T-PsA. Compared to the non-D2T group, patients in the D2T group had lower education level, longer disease duration, worse disease activity across domains, and higher functional disability at baseline (Table 1). During the 1-year treatment, the T2T adherence rate was significantly lower in the D2T group (71% vs 90%, p=0.028). Reasons for not escalating treatment in the D2T group included patients’ preference (60%), physician’s decision (20%), and no alternative treatment available (20%). Using multivariate logistic regression, a lower education level (OR:4.64, 95%CI:1.16-16.9, p=0.029) and higher Ankylosing Spondylitis Disease Activity Score (ASDAS) (OR: 1.81, 95%CI:1.07-3.04, p=0.026) were significantly associated with D2T after adjusting for baseline disease duration, number of dactylitic digits, MDA status and protocol adherence. Conclusions: Despite the implementation of the T2T-strategy and increased utilization of b/tsDMARDs, more than 40% of patients were unable to achieve MDA. Factors such as higher axial disease activity and lower education level were associated with D2T PsA. Further studies are required to determine whether a more aggressive treatment approach focusing on the axial domain should be implemented for these individuals.

Dynamics of a single domain wall between axial domains in magnetic microwire

Dynamics of a single domain wall between axial domains in magnetic microwire

Effect of Different Types of External Guide Vanes on the Performance of High-Pressure Centrifugal Compressor

In order to reduce exit swirl and obtain the desired Mach number, axial exit guide vanes (EGV) are often employed in a centrifugal compressor. NASA CC3 compressor, with wedge vane diffuser and without EGV, is considered as the base model for the analysis and validation. An axial flow domain with exit guide vane is added to this base model after the diffuser outlet to study the effect on the compressor performance. The performance of exit guide vane with different profiles: flat plate, symmetric wedge, circular arc, and airfoil vane profiles by maintaining the same chord, number of vanes, and flow angle of the vanes are studied. Numerical simulations are carried out with 60 number of exit guide vanes for all four types of vanes. Among several combinations, when the centrifugal compressor is equipped with 60 circular arc vanes as EGV, the efficiency and pressure recovery values at the design point have increased by 6.5% and 8.9%, respectively.

Spatio-temporal dynamics of an acoustically forced cryogenic coaxial jet injector

This study focuses on the application of dynamical systems theory to characterize the local susceptibility of a nonreacting, cryogenic, coaxial-jet, rocket injector to transverse acoustics. This is achieved using trajectories of the phase space obtained from high-speed imaging data, which reveal the underlying dynamical states of the system. Recurrence analysis is then used to obtain regular patterns in low-dimensional sub-space plots and provide a measure of the local response through recurrence quantification analysis. Of particular interest is quantification of the spatio-temporal coupling of the jet with the external acoustics as a function of the relative momentum flux ratio between the outer and inner jets. At lower outer-to-inner jet momentum flux ratios (J < 1), the jets have a relatively strong local response to acoustic coupling in the near field. This is followed by a sharp drop in this response further downstream where a broad range of instabilities indicates turbulent breakdown of the acoustic mode. This is in contrast to higher outer-to-inner jet momentum flux ratios (J > 1), for which the jets are intermittently coupled to the acoustic mode throughout the entire axial domain due to the presence of a second harmonic or natural instability mode. These dynamical systems analysis tools are used in conjunction with wavelet filtering to improve the utility of high-speed backlit images and are qualitatively consistent with wavelet analysis of the acoustic mode within the flow. The utility of these methods for quantifying the local susceptibility of turbulent coaxial jets to acoustic perturbations can provide powerful insight for the design and optimization of passive or active control systems for bipropellant rocket injectors and other potential propulsion applications.

Managing Psoriatic Arthritis Patients Presenting with Axial Symptoms.

Axial symptoms (i.e., back pain) are common in the general population. At the same time 25-70% of patients with psoriatic arthritis (PsA) exhibit signs of inflammatory axial involvement (axial PsA). The presence of unexplained chronic (duration ≥3 months) back pain in a patient with psoriasis or PsA should trigger evaluation of the presence of axial involvement. Evaluation of axial involvement normally involves imaging of the axial skeleton (sacroiliac joints and/or spine) in addition to clinical and laboratory evaluation. Symptomatic patients with confirmed axial PsA are treated with a combination of non-pharmacologic and pharmacologic methods including the use of non-steroidal anti-inflammatory drugs, tumour necrosis factor, interleukin 17, and Janus kinase inhibitors. Interleukin 23 blockade might also be effective in the axial domain of PsA; a dedicated clinical study is ongoing at present. Safety considerations, patient preference, as well as the presence of other disease manifestations (especially of extra-musculoskeletal manifestations-clinically relevant psoriasis, acute anterior uveitis, inflammatory bowel disease), define the choice of a specific drug or drug class.

Riemann–Hilbert Problems for Axially Symmetric Monogenic Functions in $${\mathbb {R}}^{n+1}$$

We focus on the Clifford-algebra valued variable coefficients Riemann–Hilbert boundary value problems $$\big ($$ for short RHBVPs $$\big )$$ for axially monogenic functions on Euclidean space $${\mathbb {R}}^{n+1},n\in {\mathbb {N}}$$ . With the help of Vekua system, we first make one-to-one correspondence between the RHBVPs considered in axial domains and the RHBVPs of generalized analytic function on complex plane. Subsequently, we use it to solve the former problems, by obtaining the solutions and solvable conditions of the latter problems, so that we naturally get solutions to the corresponding Schwarz problems. In addition, we also use the above method to extend the case to RHBVPs for axially null-solutions to $$\big ({\mathcal {D}}-\alpha \big )\phi =0,\alpha \in {\mathbb {R}}$$ .

Risdiplam in non-sitter patients aged 16 years and older with 5q spinal muscular atrophy.

Risdiplam has been approved for the treatment of patients with 5q spinal muscular atrophy (SMA), but data from type 2 non-sitter patients are lacking. In this study we describe our experience regarding the use of risdiplam in a series of type 2 non-sitter patients. Type 2 SMA patients over 16 years of age were administered risdiplam through the expanded access program (NCT04256265). Patients were followed-up with a battery of scales and clinical measures. Six non-sitter patients (17 to 46 years old) were treated with risdiplam. One patient reported mild adverse events (dyspepsia and headache). After 1 year of treatment, all patients showed clinically meaningful improvements in at least one scale and none of them showed any clinically meaningful deterioration. Two patients showed a clinically meaningful increase in body mass index (>5%) and two others scored higher on the Revised Upper Limb Module (>2 points). Moreover, five patients had clinically meaningful improvements on the Egen Klassifikation 2 scale (>2 points), including the motor (axial and upper limbs), bulbar (speech and swallowing), and respiratory (coughing) domains. Four subjects achieved at least one of the goals set with the Goal Attainment Scale (GAS). This series suggests that risdiplam is safe and may be effective in non-sitter SMA patients older than 16 years of age. In these patients, functional scales and the GAS would be more sensitive than motor scales to detect changes, because they include axial, bulbar, and respiratory domains. Larger studies are needed to confirm these results.

Channel impeller design for centrifugal blood pump in hybrid pediatric total artificial heart: Modeling, magnet integration, and hydraulic experiments.

The purpose of this research is to address ongoing device shortfalls for pediatric patients by developing a novel pediatric hybrid total artificial heart (TAH). The valveless magnetically-levitated MCS device (Dragon Heart) has only two moving parts, integrates an axial and centrifugal blood pump into a single device, and will occupy a compact footprint within the chest for the pediatric patient population. Prior work on the Dragon Heart focused on the development of pump designs to achieve hemodynamic requirements. The impeller of these pumps was shaft-driven and thus could not be integrated for testing. The presented research leverages an existing magnetically levitated axial flow pump and focuses on centrifugal pump development. Using the axial pump diameter as a geometric constraint, a shaftless, magnetically supported centrifugal pump was designed for placement circumferentially around the axial pump domain. The new design process included the computational analysis of more than 50 potential centrifugal impeller geometries. The resulting centrifugal pump designs were prototyped and tested for levitation and no-load rotation, followed by in vitro testing using a blood analog. To meet physiologic demands, target performance goals were pressure rises exceeding 90 mm Hg for flow rates of 1-5L/min with operating speeds of less than 5000 RPM. Three puck-shaped, channel impellers for the centrifugal blood pump were selected based on achieving performance and space requirements for magnetic integration. A quasi-steady flow analysis revealed that the impeller rotational position led to a pulsatile component in the pressure generation. After prototyping, the centrifugal prototypes (3, 4, and 5 channeled designs) demonstrated levitation and no-load rotation. Hydraulic experiments established pressure generation capabilities beyond target requirements. The pressure-flow performance of the prototypes followed expected trends with a dependence on rotational speed. Pulsatile blood flow was observed without pump-speed modulation due to rotating channel passage frequency. The results are promising in the advancement of this pediatric TAH. The channeled impeller design creates pressure-flow curves that are decoupled from the flow rate, a benefit that could reduce the required controller inputs and improve treatment of hypertensive patients.

Low Frequency Giant Magneto-Impedance Effect of Co-Rich Ribbons Induced by Joule Annealing Treatment

The giant magneto-impedance (GMI) effect of Co83.2Fe5.2Si8.8B2.8 ribbons at frequencies of &lt;1 MHz was analyzed. To improve the GMI response, a Joule annealing treatment was conducted with a direct current, and the domain structure of the ribbon surface was investigated via magneto-optical Kerr effect microscopy. The annealed ribbons show larger impedance changes under external magnetic fields, and higher field sensitivity is obtained by certain current annealing treatments. The field sensitivity of 418 and 782%/(kA/m) at 0.2 MHz and 0.8 MHz are achieved after annealing at 0.8 A for 20 min. The annealing treatment under direct electric current induces stress relaxation, and domain rearrangement, and the crystallization process gradually increases with the increasing current density, which gives rise to anisotropic reformation. The release of stresses due to Joule heating below the crystallization temperature causes the homogenous distribution of stress induced by rapid solidification and influences the elastic anisotropy, causing the domain structures to become much more regular. The crystallization, along with the precipitation of hard magnetic phases, increases the crystal anisotropy and induces the intense magnetic coupling action. Consequently, the magnetic domains in the annealed ribbons are rearranged with reformed anisotropy by Joule annealing heat and by the transverse magnetic field induced by the current. The irregular domains, with complex anisotropy in the as-cast ribbons corresponding to the weak GMI response, are transformed into regular and strip-like domains, with transverse easy magnetization after annealing at 0.4 A. After annealing at 0.8 A, the domains are further transformed into fine axial fingerprint-like domains, which are much more sensitive to the change in the axial external magnetic field, allowing for the best GMI response. These results indicate that the Joule annealing treatment is an optional method to optimize the soft magnetic properties and the GMI effect of these Co-rich ribbons at low frequencies.

Development of the Centrifugal Blood Pump for a Hybrid Continuous Flow Pediatric Total Artificial Heart: Model, Make, Measure.

Clinically-available blood pumps and total artificial hearts for pediatric patients continue to lag well behind those developed for adults. We are developing a hybrid, continuous-flow, magnetically levitated, pediatric total artificial heart (TAH). The hybrid TAH design integrates both an axial and centrifugal blood pump within a single, compact housing. The centrifugal pump rotates around the separate axial pump domain, and both impellers rotate around a common central axis. Here, we concentrate our development effort on the centrifugal blood pump by performing computational fluid dynamics (CFD) analysis of the blood flow through the pump. We also conducted transient CFD analyses (quasi-steady and transient rotational sliding interfaces) to assess the pump's dynamic performance conditions. Through modeling, we estimated the pressure generation, scalar stress levels, and fluid forces exerted on the magnetically levitated impellers. To further the development of the centrifugal pump, we also built magnetically-supported prototypes and tested these in an in vitro hydraulic flow loop and via 4-h blood bag hemolytic studies (n = 6) using bovine blood. The magnetically levitated centrifugal prototype delivered 0–6.75 L/min at 0–182 mmHg for 2,750–4,250 RPM. Computations predicted lower pressure-flow performance results than measured by testing; axial and radial fluid forces were found to be <3 N, and mechanical power usage was predicted to be <5 Watts. Blood damage indices (power law weighted exposure time and scalar stress) were <2%. All data trends followed expectations for the centrifugal pump design. Six peaks in the pressure rise were observed in the quasi-steady and transient simulations, correlating to the blade passage frequency of the 6-bladed impeller. The average N.I.H value (n = 6) was determined to be 0.09 ± 0.02 g/100 L, which is higher than desired and must be addressed through design improvement. These data serve as a strong foundation to build upon in the next development phase, whereby we will integrate the axial flow pump component.

INLET RECIRCULATION IN PARTLOAD REGIMES – RADIAL PUMP

Partload regimes of all types of centrifugal pumps are strongly and unfavorably affected by an influence of an inlet recirculation. This negative phenomenon usually occurs at pump suctions, when a circumferential velocity component of the fluid flow (derived from a rotational speed of a rotor) is dominant over an axial velocity component. Such physical effect goes hand in hand with a creation of a pump-head instability, a decrease of an overall efficiency, an excessive noise and pressure pulsations and even a possible cavitation formation. The introduced technical problem was tested/examined for a radial centrifugal pump Ns375 with a volute (spiral casing) and an axial intake domain with two potential countermeasures. Both, a physical experiment and transient numerical simulations were employed and compared on crucial levels.

Treatment Responses in Patients With Psoriatic Arthritis Axial Disease According to Human Leukocyte Antigen-B27 Status: An Analysis From the CorEvitas Psoriatic Arthritis/Spondyloarthritis Registry.

ObjectiveAxial disease is common and burdensome in patients with psoriatic arthritis (PsA). Human leukocyte antigen‐B27 (HLA‐B27) is a risk factor for axial PsA; treatment response by HLA‐B27 status is inadequately characterized. This study evaluated responses to biologic disease‐modifying antirheumatic drugs (bDMARDs) or targeted synthetic DMARDs (tsDMARDs) overall and by HLA‐B27 status in patients with PsA axial disease.MethodsThis observational study included participants in the CorEvitas (formerly Corrona) PsA/Spondyloarthritis Registry who initiated bDMARD or tsDMARD treatment at baseline, had a 6‐month follow‐up visit, fulfilled Classification Criteria for Psoriatic Arthritis, had a baseline Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of ≥4, and had known HLA‐B27 status. Disease characteristics at baseline and 6 months were evaluated overall and by HLA‐B27 status. Association between HLA‐B27 status and treatment response was evaluated using an analysis of covariance model.ResultsThe analysis included 173 bDMARD or tsDMARD treatment initiations (54 [31.2%] among patients with HLA‐B27+ status and 119 [68.8%] among patients with HLA‐B27− status). BASDAI total and component scores decreased by ≤0.84 across groups after 6 months of bDMARD or tsDMARD therapy; these changes are not considered clinically meaningful. HLA‐B27 status was not statistically significantly associated with changes in axial‐related outcomes.ConclusionIn patients with PsA axial disease, 6 months of bDMARD or tsDMARD therapy provided only mild improvements in axial‐related outcomes, irrespective of HLA‐B27 status. This continued high disease activity reflects a critical unmet need for focus on the axial domain of PsA and for additional safe and effective therapies for psoriatic axial disease.

780 Thousand Years of Upper‐Crustal Construction at a Melt‐Rich Segment of the Ultraslow Spreading Southwest Indian Ridge 50°28′E

AbstractMelt supply at the ultraslow‐spreading Southwest Indian Ridge (SWIR) has been shown to vary from nearly amagmatic, leading to ultramafic seafloor, to magmatically robust, producing fully volcanic seafloor. The center of the SWIR 50°28′E segment represents a magmatically robust endmember. High‐resolution bathymetry and backscatter, near‐bottom magnetic data, and visual observations were acquired to infer spatiotemporal variations in upper‐crustal construction over the past 780 kyr. Tectonic strain inferred from observed faults represents &lt;8% of the total plate divergence during this period. Mapped seafloor and lava morphologies show a prevalence of smooth seafloor and smooth hummocky seafloor (64% mapped area), corresponding to a dominance of high‐effusion‐rate, sheet‐lobate lavas, over hummocky seafloor (29%) that mostly comprises low‐effusion‐rate pillow lavas. This prevalence is most pronounced within a ∼5 km‐long domain at the segment center, while hummocky seafloor prevails to its east and west, indicating a substantial along‐axis decrease in average eruption rate. Across‐axis changes of seafloor morphologies and faulting pattern indicate two successive cycles of upper‐crustal construction. These cycles last ∼300 kyr, interpreted as waxing and waning magmatic phases. During waxing phases, shallow axial melt lenses (AMLs) form beneath the segment center, feeding narrow diking systems that build high‐eruption‐rate smooth domal volcanos. During waning phases, lower frequencies of melt replenishment may cause the AML to become deeper and ultimately disappear. This configuration triggers diking and hummocky‐dominated eruptions over a wider axial domain, with more faults. We propose that modes of upper‐crustal construction at slow and ultraslow mid‐ocean ridges are influenced by melt supply more than spreading rate.

Chiral polarization textures induced by the flexoelectric effect in ferroelectric nanocylinders

Polar chiral structures have recently attracted much interest within the scientific community, as they pave the way towards innovative device concepts similar to the developments achieved in nanomagnetism. Despite the growing interest, many fundamental questions related to the mechanisms controlling the appearance and stability of ferroelectric topological structures remain open. In this context, ferroelectric nanoparticles provide a flexible playground for such investigations. Here, we present a theoretical study of ferroelectric polar textures in a cylindrical core-shell nanoparticle. The calculations reveal a chiral polarization structure containing two oppositely oriented diffuse axial domains located near the cylinder ends, separated by a region with a zero-axial polarization. We name this polarization configuration "flexon" to underline the flexoelectric nature of its axial polarization. Analytical calculations and numerical simulation results show that the flexon's chirality can be switched by reversing the sign of the flexoelectric coefficient. Furthermore, the anisotropy of the flexoelectric coupling is found to critically influence the polarization texture and domain morphology. The flexon rounded shape, combined with its distinct chiral properties and the localization nature near the surface, are reminiscent of Chiral Bobber structures in magnetism. In the azimuthal plane, the flexon displays the polarization state of a vortex with an axially polarized core region, i.e., a meron. The flexoelectric effect, which couples the electric polarization and elastic strain gradients, plays a determining role in the stabilization of these chiral states. We discuss similarities between this interaction and the recently predicted ferroelectric Dyzaloshinskii-Moriya interaction leading to chiral polarization states.

Exhumation of an anatectic complex by channel flow and extrusion tectonics: structural and metamorphic evidence from the Porto–Viseu Metamorphic Belt, Central-Iberian Zone

Structural and metamorphic analyses of the Porto–Viseu Metamorphic Belt (PVMB), an anatectic complex located in the Central-Iberian Zone (CIZ), Iberian Variscan Massif, constrain the kinematic features of the polyphase Variscan deformation, as well as the boundary conditions associated with the exhumation and emplacement of the belt onto the CIZ’s lower-grade metasediments. A sharp metamorphic contrast is evident between the lowest grade rocks of the anatectic complex—garnet-staurolite mylonitic schists with a minimum metamorphic peak at P = 5.7 kbar and T = 635 °C—and the host chlorite-biotite metasediments of the CIZ. Additional P–T estimates for metatexites in the PVMB provided P = 7.6–7.9 kbar and T = 770–810 °C, confirming high-grade metamorphic peak conditions. The temperature jump between the anatectic complex and the low-grade host rocks exceeds 400 °C if the anatectic core of the belt (metatexites, diatexites, and S-type granites) is considered, implying a vertical difference of 10–17 km. The PVMB is limited in the NE by a D2 shear zone displaying normal kinematics, which has been explained so far by extensional tectonics. However, the SW boundary is limited by a D2 shear zone showing reverse kinematics. This pair of coeval and antithetical ductile shear zones bordering the PVMB, associated with the increase of the metamorphic grade towards the axial domain of the belt, is consistent with anatectic channel flow, followed by extrusion tectonics of the PVMB within an overall D2 compressive setting.

Hyposmia may predict development of freezing of gait in Parkinson's disease.

To explore the effect of olfactory dysfunction on treatment of motor manifestations in Parkinson's disease (PD). The current longitudinal retrospective cohort study consecutively recruited 108 de novo PD patients. Of whom 29 were normosmia and 79 were hyposmia, respectively, which was determined by the Korean Version of Sniffin' Sticks Test II at the time of diagnosis. All the participants underwent serial clinical examinations including Unified Parkinson's Disease Rating Scale (UPDRS), Mini-Mental State Examination, and Montreal Cognitive Assessment. The normosmic group demonstrated a significantly greater reduction of the UPDRS III score (30.3 ± 5.9 to 21.9 ± 5.1) than that of the hyposmic group (34.5 ± 9.3 to 28.5 ± 8.1) from baseline to 1-year later (p, 0.003; Bonferroni correction for p < 0.0045). Of subdomains in UPDRS III, the axial domain revealed a remarkable decrease in the normosmic group. Further, the hyposmic group exhibited a higher development rate of freezing of gait (FOG) compared to the normosmic group (29/79 (36.7%) vs 2/29 (6.9%); p, 0.002) during 33.9 ± 7.7 months of the mean follow-up period. A Cox proportional hazards model demonstrated the hyposmia to be a significant risk factor for the future development of FOG (HR, 4.23; 95% CI 1.180-17.801; p, 0.05). Our data demonstrated the olfactory dysfunction to be a significant risk factor for the development of the FOG in PD. Hyposmic PD patients should be paid more careful attention to the occurrence of FOG in the clinical practice.

Contribution to the study of the domain wall shape in bistable microwires

Magnetic domain wall in bistable glass-coated microwires is subject of the study in this paper. The domain wall between axial domains in these microwires is not a standard 180° domain wall. It is the source of a stray field, so the shape of the induced signal due to the domain wall passing through the pick-up coil is influenced by the domain wall geometry as well as by the presence of the stray field accompanying the moving wall. The present work considers the possibility of the moving domain wall having a stable conical-like shape with the apex pointing ahead. Based on this configuration, the signal induced in the pick-up coil is modelled. It is shown that the shape of the obtained model signal can explain the typical signals observed in experiments.