Transient Rise Research Articles

Dupilumab use in patients with hypereosinophilic syndromes: a multicenter case series and review of the literature

BackgroundHypereosinophilic syndromes (HES) are defined as hypereosinophilia with eosinophil-related clinical manifestations, some of which overlap in presentation with asthma, atopic dermatitis, eosinophilic esophagitis, and/or chronic rhinosinusitis with nasal polyps (CRSwNP). Dupilumab is approved to treat these conditions but can induce a transient rise in the absolute eosinophil count (AEC) and rare eosinophil-related complications. ObjectiveTo determine whether eosinophil-related complications of dupilumab are increased in HES. MethodsRetrospective chart review of patients with HES treated with dupilumab enrolled on an IRB-approved research protocol at the National Institutes of Health (NCT00001406) or receiving care at Walter Reed National Military Medical Center. Clinical response and treatment-emergent adverse events were recorded. Serum mediators were assessed in a subset of patients before and after dupilumab using stored samples. ResultsAmong the 28 patients (15 male, 13 female; median age 41.5), the most common prescribing indication for dupilumab was CRSwNP (n=11). Twenty-three patients (82%) showed significant clinical improvement on dupilumab. Hypereosinophilia (AEC >1.5x109/L) recurred or worsened in 9/20 patients on dupilumab monotherapy. Moreover, 4/20 (20%) patients developed an eosinophil-related complication with dupilumab discontinuation and/or addition of eosinophil-lowering therapy. None of the 8 patients who received dupilumab while in hematologic remission on an eosinophil-lowering biologic developed hypereosinophilia or an eosinophil-related complication. Serum IgE and eotaxin levels decreased on dupilumab therapy. ConclusionThese data suggest that dupilumab is effective in treating residual symptoms in HES patients but that the incidence of eosinophil-related complications is increased. Concomitant eosinophil-lowering therapy may reduce the risk of eosinophil-related complications during dupilumab therapy in patients with HES.

Multi-physics simulation on transient thermal response of inductive power transfer pad

Inductive power transfer is an important technological alternative for charging infrastructure, crucial for accelerating the future adoption of electronic vehicles. The magnetic components of an inductive charging pad generate inevitable thermal losses, which, if not properly managed, can exceed the pad’s safe operating temperature. Accurate simulation of both steady-state and transient thermal responses is thus essential for evaluating the pad’s suitability for real-world applications. None of the state-of-the-art thermal prediction proposals in this field, however, are able to perform long-term transient analyses efficiently while being versatile enough to simulate generic case studies. This paper presents a multi-physics methodology that aims to address this gap. The numerical framework comprises three coupled modules: electromagnetic, fluid dynamics, and solid heat conduction. To solve the issue of time-scale discrepancies, only the latter module was solved as a transient problem, while the remaining were approximated as near steady-state physics, continuously updated at every time step. The appropriateness of the resultant hybrid transient solution was verified with a fully transient solution from an equivalent heat-conjugate problem. Finally, the prediction capability of the proposed method was validated by reproducing the thermal responses of a lab-scale charging pad energized at various excitation levels and ambient conditions, both outside of and flush-embedded inside an asphalt slab. The relative errors between the measured and simulated thermal responses were consistently within 10%, demonstrating that the multi-physics approach was able to accurately simulate the long-duration transient temperature rise and drop of the test pad.

Reproductive outcomes in fresh transfer cycles and antagonists with premature luteinizing and/or progesterone surge: a single center retrospective cohort study.

The optimal outcome of assisted reproductive technology is a successful live birth after fresh embryo transfer. However, the success pregnancy rate of fresh embryo transfer cycle in antagonist protocol is lower than that observed in other protocols. Despite the use of antagonists (GnRH-ant), the incidence of luteinizing hormone surge and elevated progesterone levels remain at approximately 5%-38%. Progesterone is widely recognized to exert adverse effects on fresh embryo transfer outcomes. This study aimed to investigate the impact of luteinizing hormone surge and progesterone levels on live birth rate following fresh embryo transfer and explore appropriate progesterone thresholds to enhance pregnancy outcomes. This retrospective cohort study included a total of 1,177 antagonist protocol cycles with fresh embryo transfer. The patients were divided into four groups based on the presence of premature LH surge and progesterone level on trigger day>1.5ng/ml. Then, the relationship between the variables and the pregnancy outcome was analyzed and compared in each group. The transient rise of luteinizing hormone did not impact pregnancy outcomes (P=0.345; P=0.3; P=0.787), in contrast to progesterone levels on the day of hCG administration (P=0.047*; P=0.015*; P=0.021*). In cases with luteinizing hormone surge, elevated progesterone levels were correlated with higher antral follicle count (AFC), and as progesterone levels increased, a greater quantity of oocytes and embryos were obtained. However, there was no statistically significant difference in pregnancy outcomes. In cases without luteinizing hormone surge, elevated progesterone levels led to significantly poorer pregnancy outcomes. Furthermore, the curve-fitting and threshold-effect analysis revealed a notable decline in live birth rates when progesterone exceeded or equaled 1.10ng/ml (OR, 0.25; 95% CI, 0.09-0.66; P = 0.005*). The GnRH-ant dosage addition should be carefully selected in flexible antagonist protocols. The presence of elevated progesterone levels may be associated with improved embryo quality when luteinizing hormone surge occurred. In the absence of a luteinizing hormone surge, progesterone levels showed a larger impact on the pregnancy outcome, and fresh embryo transfer should not be performed if the progesterone level on the day of hCG administration is higher than 1.10ng/ml.

NIR Laser Irradiation Promotes Osteogenic Differentiation of PDLSCs Through the Activation of TRPV1 Channels and Subsequent Calcium Signaling.

Near-infrared (NIR) irradiation has shown potential to stimulate osteogenic differentiation, but the mechanisms are not fully understood. The study is to investigate the effects of NIR laser irradiation on osteoblastic differentiation. Human periodontal ligament stem cells (hPDLSCs) were cultured in osteogenic medium and exposed to 810 nm NIR laser at 0.5 J/cm2 every 48 h. The transient receptor potential vanilloid (TRPV1) channel inhibitor capsazepine (CPZ) was used to evaluate the role of calcium influx. Osteogenic differentiation was assessed by proliferation (CCK-8), alkaline phosphatase (ALP) activity, mineralization (Alizarin Red), and expression of bone markers by PCR and Western blot over 2 weeks. Intracellular calcium was measured by Fluo-4M dye and flow cytometry. Results showed that NIR irradiation enhanced hPDLSC proliferation, ALP activity, mineralization, and bone marker expression, indicating increased osteogenic differentiation. These effects were inhibited by CPZ. NIR induced a transient rise in intracellular calcium peaking at 3 min, which was blocked by CPZ. In conclusion, this study demonstrates that NIR laser irradiation promotes osteogenic differentiation of PDLSCs through the activation of TRPV1 channels and subsequent calcium signaling. Further research is warranted to optimize the treatment parameters and elucidate the detailed signaling pathways involved, paving the way for the clinical application of NIR therapy in the treatment of bone disorders and periodontal disease.

Orientation-independent-DIC imaging reveals that a transient rise in depletion attraction contributes to mitotic chromosome condensation.

Genomic information must be faithfully transmitted into two daughter cells during mitosis. To ensure the transmission process, interphase chromatin is further condensed into mitotic chromosomes. Although protein factors like condensins and topoisomerase IIα are involved in the assembly of mitotic chromosomes, the physical bases of the condensation process remain unclear. Depletion attraction/macromolecular crowding, an effective attractive force that arises between large structures in crowded environments around chromosomes, may contribute to the condensation process. To approach this issue, we investigated the "chromosome milieu" during mitosis of living human cells using an orientation-independent-differential interference contrast module combined with a confocal laser scanning microscope, which is capable of precisely mapping optical path differences and estimating molecular densities. We found that the molecular density surrounding chromosomes increased with the progression from prophase to anaphase, concurring with chromosome condensation. However, the molecular density went down in telophase, when chromosome decondensation began. Changes in the molecular density around chromosomes by hypotonic or hypertonic treatment consistently altered the condensation levels of chromosomes. In vitro, native chromatin was converted into liquid droplets of chromatin in the presence of cations and a macromolecular crowder. Additional crowder made the chromatin droplets stiffer and more solid-like. These results suggest that a transient rise in depletion attraction, likely triggered by the relocation of macromolecules (proteins, RNAs, and others) via nuclear envelope breakdown and by a subsequent decrease in cell volumes, contributes to mitotic chromosome condensation, shedding light on a different aspect of the condensation mechanism in living human cells.

Rapid Ventricular Pacing for Clipping of Intracranial Aneurysms: A Single-centre Retrospective Case Series.

Multiple strategies exist to facilitate microdissection and obliteration of intracranial aneurysms during microsurgical clipping. Rapid ventricular pacing (RVP) can be used to induce controlled transient hypotension to facilitate aneurysm manipulation. We report the indications and outcomes of intraoperative RVP for clipping of ruptured and unruptured complex aneurysms. We completed a retrospective review of adult patients who underwent RVP-facilitated elective and emergent microsurgical aneurysm clipping by a single senior neurosurgeon between 2016 and 2023. Intraoperative RVP was performed at a rate of 150 to 200 beats per minute through a transvenous pacing wire and repeated as needed based on surgical requirements. Intraoperative procedural and pacing data and perioperative cardiac and neurosurgical variables were collected. Forty patients were included in this study. The median (interquartile range) number of pacing episodes per patient was 8 (5 to 14), resulting in a median mean arterial pressure of 37 (30 to 40) mm Hg during RVP. One patient developed wide complex tachycardia intraoperatively, which resolved after cardioversion. Fifteen out of 36 (42%) patients who had postoperative troponin measurements had at least one troponin value above the 99th percentile upper reference limit. One patient had markedly elevated troponin with anterolateral ischemia in the context of massive postoperative intracranial hemorrhage. There were no other documented intraoperative or postoperative cardiac events. This retrospective case series suggests that RVP could be an effective adjunct for clipping of complex ruptured and unruptured aneurysms, associated with transient troponin rise but rare postoperative cardiac complications.

Study on the burial depth calculation method for AC submarine cable based on the surface optical fiber monitoring temperature

AbstractThe partial exposure of submarine cable may cause damage to the metal sheath, which will affect its safe and stable operation. Existing detection methods for burial depth of submarine cables are difficult to implement and have a long detection period. In this contribution, a method is proposed to calculate the burial depth of alternating current (AC) submarine cable based on surface optical fiber monitoring temperature. According to the functional relationship between the transient temperature rise of submarine cable outer sheath above the ambient temperature and the burial depth (in the IEC‐60853 standard), the burial depth of submarine cables is calculated. The optical fiber temperature, electric load and meteorological temperature data are used for 30 consecutive days in September 2020 to calculate the change of burial depth of AC 500 kV oil‐filled submarine cable. The calculation results are basically consistent with the detection conclusion of side‐scan sonar, which shows that the method can accurately calculate the burial depth of submarine cables and locate the exposed position. This provides a theoretical basis for the intelligent operation and maintenance of AC submarine cables.

Higher alpha diversity and Lactobacillus blooms are associated with better engraftment after fecal microbiota transplant in inflammatory bowel disease

Fecal Microbiota Transplant (FMT) has shown some success in treating inflammatory bowel diseases (IBD). There is emerging evidence that host engraftment of donor taxa is a tenet of successful FMT. We undertook a double-blind, randomized, placebo-controlled pilot study to characterize the response to FMT in children and young adults with mild to moderate active Crohn’s disease (CD) and ulcerative colitis (UC). Subjects with CD or UC were randomized to receive antibiotics and weekly FMT or placebo in addition to baseline medications. We enrolled 15 subjects aged 14–29 years. Four subjects had CD, and 11 had UC. Subjects exhibited a wide range of microbial diversity and donor engraftment. Specifically, engraftment ranged from 26 to 90% at week 2 and 3–92% at 2 months. Consistent with the current literature, increases over time of both alpha diversity (p < 0.05) and donor engraftment (p < 0.05) correlated with improved clinical response. We discovered that the post-antibiotic but pre-FMT time point was rich in microbial correlates of eventual engraftment. Greater residual alpha diversity after antibiotic treatment was positively correlated with engraftment and subsequent clinical response. Interestingly, a transient rise in the relative abundance of Lactobacillus was also positively correlated with engraftment, a finding that we recapitulated with our analysis of another FMT trial.

Numerical modeling of cavity collapse water hammer in pipeline systems: Internal mechanisms and influential factors of transient flow and secondary pressure rise dynamics

This study explores the dynamics of pressure wave propagation and cavitation in pressurized pipelines during and after the rapid closure of the pipeline's end ball valve, utilizing a three-dimensional computational fluid dynamics approach with the method of characteristics, validated against Bergant and Simpson's experimental data of three degrees of cavitation. It innovatively examines transient pressure dynamics through both energy transformation and wave propagation perspectives, focusing on the phases of water column separation and coalescence, and the dynamics of flow interruption bubbles. The research delves into the detailed mechanisms of pressure wave propagation and further assesses the effects of physical factors. Key findings include: (1) As initial inlet velocities increase, cavitation starts earlier, extends further, and intensifies, with higher final volume fractions near the valve, indicating that higher velocities exacerbate cavitation. Higher inlet velocities also correlate with more intricate and expansive vortex formations. (2) Secondary pressure surges in water hammer result from the superposition of two-stage positive pressure waves. Initially, positive pressure waves within the conduit reflect twice from air pockets and the upstream boundary, remaining positive. Subsequently, they interact with secondary positive pressure waves reflected by the valve, causing a secondary pressure surge. (3) The fluid flow is laterally symmetry in the pipe cross section, except for minor local asymmetrical spikes in areas with vapor bubbles. Velocity discrepancies are notable near the pipe walls due to vapor accumulation, primarily on the upper wall due to buoyancy. This accumulation may narrow the flow area, possibly accelerating the water passing by. (4) Lower flow velocities, downward inclines, and slower valve closures diminish secondary pressure rise amplitudes in water hammer events, while reduced static heads intensify cavitation despite lessening pulse amplitudes. These findings offer valuable insights for the design and operational guidance of complex hydraulic systems during transient processes in urban water supplies.

Clinical and endocrine features of orthostatic intolerance detected in patients with long COVID

Orthostatic intolerance (OI) is a key symptom of long COVID; however, the pathophysiology remains unknown. Among 688 long COVID patients who visited our clinic during the period from February 2021 to April 2023, 86 patients who were suspected of having OI and who underwent an active standing test (ST) were investigated to elucidate the clinical characteristics of OI in patients with long COVID. Of the 86 patients, 33 patients (38%) were ST-positive. Nausea and tachycardia in daily life were frequent complaints in the ST-positive group. The increase in heart rate (HR) during the ST was significantly greater during a 10-min period after standing in the ST-positive group (+ 30 bpm) than in the ST-negative group (+ 16 bpm). The initial increase in diastolic blood pressure (DBP) just after standing was significantly greater in the ST-positive group (+ 14 mmHg) than in the ST-negative group (+ 9 mmHg). Serum cortisol levels in the ST-positive patients aged over 20 years were higher and growth hormone levels in the patients under 20 years of age were lower than those in the ST-negative group. Autonomous nervous symptoms, transient DBP rise with increasing HR after standing, and endocrine dysfunctions are helpful for detecting OI related to long COVID.

Evaluation of romosozumab's effects on bone marrow adiposity in postmenopausal osteoporotic women: results from the FRAME bone biopsy sub-study.

Romosozumab, a humanized monoclonal antibody that binds and inhibits sclerostin, produces a marked increase in bone formation with a concomitant decreased bone resorption. This transient rise in bone formation in the first 2 months of treatment is mainly due to an increased modeling-based bone formation. This requires the recruitment and differentiation of osteoblasts, one possibility being a preferential switch in commitment of precursors to osteoblasts over adipocytes. The purpose of this study was to analyze the marrow adiposity in transiliac bone biopsies at months 2 or 12 from the FRAME biopsy sub-study in patients receiving romosozumab or placebo. The total adipocyte area, number, and density were measured on the total cancellous bone area. The size and shape at the individual adipocyte level were assessed including the mean adipocyte area, perimeter, min and max diameters, and aspect ratio. No significant difference in total adipocyte area, number, or density between placebo and romosozumab groups was observed at months 2 and 12, and no difference was observed between 2 and 12months. After 2 or 12months, romosozumab did not modify the size or shape of the adipocytes. No relationship between the adipocyte parameters and the dynamic parameters of bone formation could be evidenced. In conclusion, based on the analysis of a small number of biopsies, no effect of romosozumab on bone marrow adiposity of iliac crest was identified after 2 and 12months suggesting that the modeling-based formation observed at month 2 was not due to a preferential commitment of the precursor to osteoblast over adipocyte cell lines but may result from a reactivation of bone lining cells and from a progenitor pool independent of the marrow adipocyte population.

Accurate modeling of thermal-optical performance for a lightweight SiC mirror

The SiC mirror has excellent structural rigidity and thermal stability, making it widely applicable in high-power optical systems. This manuscript aims to establish a coupled analysis model of thermal-optical performance for a lightweight SiC reflector under high-power laser irradiation. First, based on the Fourier principle, the transient temperature rise of the mirror is analyzed using the finite element method, considering boundary conditions such as heat source and convective radiation. A transient thermal response model for the mirror is established. Then, the reflective surface deformation is solved based on the mirror temperature field. By processing the data of node deformation, the decrease in the mirror surface shape accuracy (RMS) value is obtained. Finally, the experimental platform is built to measure the transient temperature rise and wavefront aberration change of the mirror after high-power laser excitation. Based on the deviation between the calculated data of the analysis model and the measured data, thermodynamic parameters in the analysis model are adjusted according to the principle of minimum residual. The research findings of this manuscript can be utilized for accurately predicting the temperature rise and optical degradation of SiC mirrors under high-power laser irradiation and provide a theoretical basis for the subsequent design of actively compensating methods for thermal-induced distortions.

A New Technique with Scleral Grooves for Sutureless Scleral Fixation of the Carlevale Intraocular Lens.

A novel technique is described employing scleral grooves to facilitate sutureless scleral fixation of the Carlevale intraocular lens (CIL). We describe its use in a series of 47 patients with aphakia. A retrospective study of all patients with aphakia who underwent CIL implantation with the new technique by a single surgeon during 1year. The novelty of this technique consists in the creation of two partial-thickness linear sclerotomies (grooves), 180° apart, 2mm from and parallel to the limbus. In the middle of each groove a full-thickness sclerotomy is performed to facilitate externalization of the CIL anchors. The groove allows the anchor to plug the full-thickness sclerotomy and to rest within the sclera without protrusion. Reported outcomes include pre-operative/post-operative visual acuity, post-operative spherical equivalent and surgical complications. Follow-up was a minimum of 6months. Forty-eight eyes of 47 patients with aphakia with a mean age of 74years (range 31-90years) are included. The commonest causes of aphakia were intraocular lens (IOL) subluxation,with or without exfoliation (54.2%), complicated cataract surgery (29.2%), crystalline lens luxation (6.3%) and trauma (4.1%). All CILs inserted with the new technique stayed successfully in situ during follow-up. Median pre-operative best-corrected visual acuity (0.75 logMAR; range 0.1-2.7) significantly improved to 0.5 logMAR post-operatively (p < 0.001). Moreover, 78% and 65% of the operated cases were within 1.0 and 0.5 diopters, respectively, from intended refraction. The most common complications were transient cystoid macular oedema (8.3%) and transient intraocular pressure rise (8.3%), all of which resolved within 2months. The proposed modification of sutureless scleral fixation of the CIL appears safe and effective. In our experience it is less time consuming and easier to perform than previous techniques and may therefore offer a useful future option.

Retinal microglial cells increase expression and release of IL-1β when exposed to ATP.

Cytokine IL-1β is an early component of inflammatory cascades, with both priming and activation steps required before IL-1β release. Here, the P2X7 receptor (P2X7R) for ATP was shown to both prime and release IL-1β from retinal microglial cells. Isolated retinal microglial cells increased expression of Il1b when stimulated with endogenous receptor agonist extracellular ATP; ATP also rapidly downregulated expression of microglial markers Tmem119 and Cd206. Changes to all three genes were reduced by specific P2X7R antagonist A839977, implicating the P2X7R. Microglial cells expressed the P2X7R on ramifications and responded to receptor agonist BzATP with robust and rapid rises in intracellular Ca 2+ . BzATP increased expression of IL-1β protein colocalizing with CX3CR1-GFP in retinal wholemounts consistent with microglial cells. ATP also triggered release of IL-1β from isolated retinal microglia into the bath; release was inhibited by A839977 and induced by BzATP, supporting a role for the P2X7R in release as well as priming. The IL-1β release triggered by ATP was substantially greater from microglial cells compared to astrocytes from the optic nerve head region. Il1b expression was increased by a transient rise in intraocular pressure and Il1b levels remained elevated 10 days after a single IOP elevation. In summary, this study suggests the P2X7 receptor can both prime IL-1β levels in microglial cells and trigger its release. The P2Y12R was previously identified as a chemoattractant for retinal microglia, suggesting the recruitment of the cells towards the source of released extracellular ATP could position microglia for P2X7R receptor, enabling both priming and release of IL-1β.

Modulating Ca2+ influx into adrenal chromaffin cells with short-duration nanosecond electric pulses

Isolated bovine adrenal chromaffin cells exposed to single 2-, 4-, or 5-ns pulses undergo a rapid, transient rise in intracellular Ca2+ mediated by Ca2+ entry via voltage-gated Ca2+ channels (VGCCs), mimicking the activation of these cells in vivo by acetylcholine. However, pulse durations 150 ns or longer elicit larger amplitude and longer-lived Ca2+ responses due to Ca2+ influx via both VGCCs and a yet to be identified plasma membrane pathway(s). To further our understanding of the differential effects of ultrashort versus longer pulse durations on Ca2+ influx, chromaffin cells were loaded with calcium green-1 and exposed to single 3-, 5-, 11-, 25-, or 50-ns pulses applied at their respective Ca2+ activation threshold electric fields. Increasing pulse duration from 3 or 5 ns to only 11 ns was sufficient to elicit increased amplitude and longer-lived Ca2+ responses in the majority of cells, a trend that continued as pulse duration increased to 50 ns. The amplification of Ca2+ responses was not the result of Ca2+ release from intracellular stores and was accompanied by a decreased effectiveness of VGCC inhibitors to block the responses and a reduced reliance on extracellular Na+ and membrane depolarization to evoke the responses. Inhibitors of pannexin channels, P2X receptors, or non-selective cation channels failed to attenuate 50-ns-elicited Ca2+ responses, ruling out these Ca2+-permeable channels as secondary Ca2+ entry pathways. Analytical calculations and numerical modeling suggest that the parameter that best determines the response of chromaffin cells to increasing pulse durations is the time the membrane charges to its peak voltage. These results highlight the pronounced sensitivity of a neuroendocrine cell to pulse durations differing by only tens of nanoseconds, which has important implications for the future development of nanosecond pulse technologies enabling electrostimulation applications for spatially focused and graded in vivo neuromodulation.

RELAP5-3D validation studies based on the High Temperature Test facility

In the spring and summer of 2019, experiments were conducted at the High Temperature Test Facility (HTTF) that form the basis of an upcoming high-temperature gas-cooled reactor (HTGR) thermal hydraulics (T/H) benchmark. HTTF is an integral effects test facility for HTGR T/H modeling validation. This paper presents RELAP5-3D models of two of those experiments: PG-27, a pressurized conduction cooldown (PCC); and PG-29, a depressurized conduction cooldown (DCC). These models used the RELAP5-3D model of HTTF originally developed by Paul Bayless as a starting point. The sensitivity analysis and uncertainty quantification code, RAVEN was used to perform calibration studies for the steady-state portion of PG-27. We developed four PG-27 calibrations based on steady-state conditions. These calibrations all used an effective thermal conductivity equal to 36 % of the measured thermal conductivity, but they differed with respect to the frictional pressure drops and radial conduction models. These models all captured the trends in steady-state temperature distributions and transient temperature behavior well. All four calibrations show room for improvement in predicting the transient temperature rise. The smallest error in temperature rise during the transient was a 21 % underprediction, and the largest was a 48 % underprediction. The errors in transient temperature rise are largely a result of a mismatch in power density between the RELAP5-3D model and the experiment due to the location of active heater rods along the boundary between heat structures in the model. The best of these calibrations was applied to PG-29 to model the DCC. Once again, temperatures during the transient were underpredicted but trends in temperature were captured. The RELAP5-3D model captured trends in the data but could not reproduce measured temperatures exactly. This result is not attributed to deficiencies in the experimental data or to RELAP5–3D itself. Rather, this result likely arises due to the some of the assumptions and decisions made when the RELAP5-3D model was first developed, prior to the execution of HTTF experiments. An agreement in prediction of temperature trends but challenges reproducing HTTF temperatures within measurement uncertainty is consistent with previous analyses of HTTF in the literature. Future RELAP5-3D validation activities centered around HTTF may be able to provide greater insight into the code’s capabilities for HTGR modeling with a more finely nodalized model.

Core loss determination in electric machines using short‐time transient thermal measurements

AbstractThis paper introduces a novel application of the inverse modelling method, which is designed to estimate core losses in both the stator and rotor regions of an electrical machine. The technique focuses on the use of short‐term transient temperature measurements obtained from the stator core of a slotless induction machine, with a focus on validating the measured temperature rise through a forward model. The measurement setup involves two primary approaches: (i) the use of thermal sensors embedded in a printed circuit board inside the stator core and (ii) surface sensors embedded on the stator yoke. Through the use of this innovative approach, the results indicate that the inverse modelling technique is highly effective in predicting core losses based on short‐time transient temperature rise measurements.

The bile acid receptor TGR5 inhibits platelet activation and thrombus formation

Liver failure and cirrhosis are characterized by abnormal hemostasis with aberrant platelet activation. In particular, the consequences of cholestatic liver disease and molecular mechanisms, including the role of bile acids leading to impaired platelet responses, are not well understood. Here, we demonstrate that bile acids inhibit human and murine platelet activation, adhesion and spreading, leading to reduced thrombus formation under flow conditions. We identified the G-protein coupled receptor TGR5 in platelets and provide support for its role as mediator of bile acid-induced impairment of platelet activation. In the liver, TGR5 couples to Gαs proteins, activates the adenylate cyclase to induce a transient cAMP rise and stimulates the MAPK signaling pathway to regulate cholangiocyte proliferation, hepatocyte survival and inflammation. In this report, we demonstrate that the genetic deficiency of TGR5 in mice led to enhanced platelet activation and thrombus formation, suggesting that TGR5 plays an important role in hemostasis. Mechanistically, platelet inhibition is achieved by TGR5 mediated PKA activation and modulation of AKT and ERK1/2 phosphorylation. Thus, this report provides evidence for the ability of TGR5 ligands to reduce platelet activation and identifies TGR5 agonism as a new target for the prevention of cardiovascular diseases.

Effect of operating conditions and surface roughness on grease lubrication efficiency

The aim of this paper is to investigate the effect of operating parameters (load and rotational speed) and arithmetic mean deviation (Ra) roughness value on temperature rise and tribological behavior of greased point contact under heavy load. The 3-factor, 4-level orthogonal friction experiments are designed and carried out. The moving point heat source integration method is applied to calculate the transient temperature rise of interfaces. The results show that the case with load 1900 N, rotational speed 260 rpm and Ra 0.4 μm has the highest friction coefficient and temperature rise. The grease fails and layered spalling and oxidative wear occur on the wear scar. Four second-order regression models are established to predict friction coefficient and the maximum temperature rise under different load, rotational speed and surface roughness. And the determination coefficients R2 of them are higher than 97 %. The models are helpful to determine if the working conditions fall within effective lubrication range and avoid severe damage.

Direct observation of strong momentum-dependent electron-phonon coupling in a metal.

Phonon scattering in metals is one of the most fundamental processes in materials science. However, understanding such processes has remained challenging and requires detailed information on interactions between phonons and electrons. We use an ultrafast electron diffuse scattering technique to resolve the nonequilibrium phonon dynamics in femtosecond-laser-excited tungsten in both time and momentum. We determine transient populations of phonon modes which show strong momentum dependence initiated by electron-phonon coupling. For phonons near Brillouin zone border, we observe a transient rise in their population on a timescale of approximately 1 picosecond driven by the strong electron-phonon coupling, followed by a slow decay on a timescale of approximately 8 picosecond governed by the weaker phonon-phonon relaxation process. We find that the exceptional harmonicity of tungsten is needed for isolating the two processes, resulting in long-lived nonequilibrium phonons in a pure metal. Our finding highlights that electron-phonon scattering can be the determinant factor in the phonon thermal transport of metals.