Fusion Plasmas Research Articles

Stress, strain, neutron transport and radiation effects in a full fusion tokamak device: A virtual MAST-U study

A finite-element method (FEM) model for the Mega-Ampere Spherical Tokamak - Upgrade (MAST-U) fusion tokamak has been developed to evaluate stress and deformations in the full device structure and to assess the stability of the whole tokamak with respect to its simulated exposure to an artificial level of neutron irradiation. Here, we use MAST-U as a proxy for a fusion power plant to explore the level of fidelity made possible by modern supercomputing systems. Gravity and atmospheric pressure were used to test the high-resolution FEM model, involving in excess of 122 million elements. Taking the MASTU fusion plasma as a neutron source, we perform full-scale neutron transport calculations to quantify spatial variations in the neutron flux and assess the neutron radiation exposure across the structure. This is a first step towards applying recently developed multiscale computational tools to evaluate the spectrum of stress in the tokamak, identifying the location of stress concentrations as well as their magnitude. This study provides an example of full fusion device neutronics and FEM simulations which are enabling UKAEA to define computational requirements for modelling a whole fusion power plant as well as for specifying operating conditions for the relevant materials.

Experimental and theoretical research progress of <sup>2</sup>P<sub>1/2 </sub> – <sup>2</sup>P<sub>3/2</sub> transitions of highly charged boron-like ions

The precise measurement of the fine structure and radiative transition properties of highly charged ions (HCI) is essential for testing fundamental physical models, including strong-field quantum electrodynamics (QED) effects, electron correlation effects, relativistic effects, and nuclear effects. These measurements also provide critical atomic physics parameters for astrophysics and fusion plasma physics. Compared with the extensively studied hydrogen-like and lithium-like ion systems, boron-like ions exhibit significant contributions in terms of relativistic and QED effects in their fine structure forbidden transitions. High-precision experimental measurements and theoretical calculations of these systems provide important avenues for further testing fundamental physical models in multi-electron systems. Additionally, boron-like ions are considered promising candidates for HCI optical clocks. This paper presents the latest advancements in experimental and theoretical research on the ground state <sup>2</sup>P<sub>3/2</sub>—<sup>2</sup>P<sub>1/2</sub> transition in boron-like ions, and summarizes the current understanding of their fine and hyperfine structures. It also discusses a proposed experimental setup for measuring the hyperfine splitting of boron-like ions by using an electron beam ion trap combined with high-resolution spectroscopy. This proposal aims to provide a reference for future experimental research on the hyperfine splitting of boron-like ions, to test the QED effects with higher precision, extract the radius of nuclear magnetization distribution, and validate relevant nuclear structure models.

Reactive collisions between electrons and BeH+ above dissociation threshold.

Our previous studies of dissociative recombination and vibrational excitation/de-excitation of the BeH+ ion, based on the multichannel quantum defect theory, are extended to collision energies above the dissociation threshold, taking into account the vibrational continua of the BeH+ ion and, consequently, its dissociative excitation. We have also significantly increased the number of dissociative states of 2Π, 2Σ+ and 2Δ symmetry included in our cross section calculations, generating the most excited ones by using appropriate scaling laws. Our results are suitable for modeling the kinetics of BeH+ in edge fusion plasmas for collision energies up to 12 eV.

Formation of fast-ignition hotspots and propagartion of burning waves in pre-compressed isochoric plasmas

The formation and evolution of hotspots is important for achieving ignition and high energy gain in inertial fusion process. However, most of relevant studies are carried out on pre-compressed plasmas with an isobaric configuration, the evolution of the hotspot in a plasma with an isochoric configuration is rarely studied. In this paper, a semi-analytical model is developed to describe the evolution of the hotspot boundary and propagation of fusion burning waves for a high-density pre-compressed plasma with an isochoric configuration in the double-cone ignition scheme. For the shock wave, the strong shock wave approximation and the quasi-isobaric approximation are reasonable. The quasi-isobaric approximation shows that as the plasma density behind the shock wave increases, the plasma temperature decreases. Because of these, the range of <inline-formula><tex-math id="M4">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M4.png"/></alternatives></inline-formula>-particles decreases rapidly behind the shock wave, forming an <inline-formula><tex-math id="M5">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M5.png"/></alternatives></inline-formula>-particle absorption peak. Therefore, considering that the hotspot is the main region where <inline-formula><tex-math id="M6">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M6.png"/></alternatives></inline-formula>-particles are produced and deposited, the position of the shock peak can be used to identify the boundary of the hotspot in a high-density plasma with an isochoric configuration. It also shows that a “self-regulating burning process” exists in the burning process of the isochoric hotspot, most of <inline-formula><tex-math id="M7">\begin{document}$ {\mathrm{\alpha }} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231474_M7.png"/></alternatives></inline-formula>-particles are deposited in the stable region and behind the shock, and finally, transport through the shock peak and heat the cold fuel, resulting in the temperature rising. In the high-density hotspots of plasma with an isochoric configuration, the deposition of α-particles behaves as an obvious non-uniform distribution effect. By analyzing the non-uniform deposition of α-particles, the deposition rate of α-particles at the edge of spherical uniform hotspot is calculated, then the temperature and density evolution of the isochoric hotspot can be well described. The model can be used to estimate the Lawson parameter of the hotspots at the end of the early stage of ignition. It is found that a lower fast electron energy is more beneficial to ignition and high gain operation of fusion plasma. It is also shown that the high density of the hotspots in the isochoric plasma will lead to a higher fusion burning rate, which can offset the negative influence of the shock wave and even achieve higher energy gain. The semi-analytical model is verified by the hydrodynamic simulations of O-SUKI-N.

Influence of lower hybrid wave injection on peeling-ballooning modes

The high-confinement mode (H-mode) significantly enhances the energy and particle confinement in fusion plasma compared with the low-confinement mode (L-mode), and it is the basic operation scenario for ITER and CFETR. Edge localized mode (ELM) often appears in H-mode, helping to expel impurities to maintain a longer stable state. However, the particle burst and energy burst from ELM eruptions can severely damage the first wall of fusion device, so, it is necessary to control the ELM. Experiments on EAST tokamak and HL-2A tokamak have been conducted with ELM mitigation by lower hybrid wave (LHW), confirming the effect of LHW on ELMs, but the physical mechanism of ELM mitigation by LHW is still not fully understood. In this paper, the influences of LHW injection on the linear and nonlinear characteristics of peeling-ballooning mode (P-B mode) are investigated in the edge pedestal region of H-mode plasma in tokamak by using the BOUT++ code. The simulations take into consideration both the conventional main plasma current driven by LHW and the three-dimensional perturbed magnetic field generated by the scrape-off layer helical current filament (HCF) on the P-B mode. The linear results show that the core plasma current driven by LHW moves the linear toroidal mode spectrum towards higher mode numbers and lower growth rates by reducing the normalized pressure gradient and magnetic shear of the equilibrium. Nonlinear simulations indicate that due to the broadening of the linear mode spectrum, the core current driven by LHW can reduce the pedestal energy loss caused by ELM through globally suppressing different toroidal modes of the P-B mode, and the three-dimensional perturbed magnetic field generated by LHW-driven HCF can reduce the energy loss caused by ELMs through promoting the growth of modes other than the main mode and enhancing the coupling between different modes. It is found in the study that the P-B mode promoted by the three-dimensional perturbed magnetic field generated by HCF has a mode number threshold, and when the dominant mode of the P-B mode is far from the mode number threshold driven by the three-dimensional perturbed magnetic field, the energy loss due to ELMs is more significantly reduced. These results contribute to a more in-depth understanding of the physical mechanism in ELM control experiment by LHW.

Young Plasma Attenuated Chronic Kidney Disease Progression after Acute Kidney Injury by Inhibiting Inflammation in Mice.

In the aged patients suffering from acute kidney injury, the risk for progression to chronic kidney disease and mortality is high. Aging accompanied by glomerulosclerosis, interstitial inflammation, and fibrosis might be one of the underlying mechanisms for vulnerability. In addition to sustained activation of the renin-angiotensin system, persistent chronic inflammation with tertiary lymphoid tissue formation is more common and is associated with disease progression in the aged kidney after acute injury. Based on recent laboratory evidence that young blood can rejuvenate the brain, muscle, and heart, we were intrigued by the possible protective effect of young plasma on acute kidney injury in aged mice. Here, we demonstrated that young plasma from 2-month-old mice could attenuate chronic kidney disease progression in 15-month-old mice subjected to acute kidney injury induced by ischemia-reperfusion. In the aged mice after acute kidney injury, young plasma administration decreased tubulointerstitial injury, fibrosis, and tertiary lymphoid tissue formation in kidneys assessed on day 28 after acute injury despite no significant beneficial effect on injury severity and survival. Mechanistically, young plasma inhibited angiotensin II-activated chemokines in pericytes that were responsible for tertiary lymphoid tissue formation. In summary, our data provide evidence that young plasma attenuates the transition from acute kidney injury to chronic kidney disease in aged mice. The therapeutic potential of young plasma infusion or exchange in the aged patients suffering acute kidney injury needs to be addressed in clinical trials.

Stochastic Dynamics of Fusion Low-to-High Confinement Mode (L-H) Transition: Correlation and Causal Analyses Using Information Geometry.

We investigate the stochastic dynamics of the prey-predator model of the Low-to-High confinement mode (L-H) transition in magnetically confined fusion plasmas. By considering stochastic noise in the turbulence and zonal flows as well as constant and time-varying input power Q, we perform multiple stochastic simulations of over a million trajectories using GPU computing. Due to stochastic noise, some trajectories undergo the L-H transition while others do not, leading to a mixture of H-mode and dithering at a given time and/or input power. One of the consequences of this is that H-mode characteristics appear at a smaller input power Q<Qc (where Qc is the critical value for the L-H transition in the deterministic system) as a secondary peak of a probability density function (PDF) while dithering characteristics persists beyond the power threshold for Q>Qc as a second peak. The coexisting H-mode and dithering near Q=Qc leads to a prominent bimodal PDF with a gradual L-H transition rather than a sudden transition at Q=Qc and uncertainty in the input power. Also, a time-dependent input power leads to increased variability (dispersion) in stochastic trajectories and a more prominent bimodal PDF. We provide an interpretation of the results using information geometry to elucidate self-regulation between zonal flows, turbulence, and information causality rate to unravel causal relations involved in the L-H transition.

MUSES: A nonlinear magnetohydrodynamics discontinuous Galerkin code for fusion plasmas

The article describes initial steps toward the development of our nonlinear magnetohydrodynamics code, MUSES. Unstructured grids and general coordinates are employed so that MUSES code is expected to have a capability to represent realistic geometries of fusion devices. Discontinuous Galerkin method is chosen as a code framework because of its high spatial accuracy and numerical stability on unstructured grids. The governing equation of the ideal magnetohydrodynamics in this work is Powell 8-wave model which can mitigate the divergence-free issue. Roe scheme is used as a numerical flux since the Powell 8-wave model is a nonconservative system. A cross code comparison is carried out with a linear magnetohydrodynamics code, MINERVA. Owing to discontinuous Galerkin method, a linear theory of an ideal internal kink mode is reproduced quantitatively although the upwind method is employed for numerical stability.

Quantum-mechanical four-body versus semi-classical three-body theories for double charge exchange in collisions of fast alpha particles with helium targets

AbstractWithin the two-channel distorted wave second-order perturbative theoretical formalism, we study capture of both electrons from helium-like targets by heavy nuclei as projectiles at intermediate and high impact energies. The emphasis is on the four-body single-double scattering (SDS-4B) method and the three-body continuum distorted wave impact parameter method (CDW-3B-IPM). The SDS-4B method deals with the full quantum-mechanical correlative dynamics of all the four interactively participating particles (two electrons, two nuclei). The CDW-3B-IPM is a semi-classical three-body independent particle model (one electron, two nuclei), using a combinatorial calculus to describe double capture by a product of two uncorrelated probabilities, integrated over impact parameters. Both theories share a common feature in having altogether two electronic full Coulomb continuum wave functions. One such function is centered on the projectile nucleus in the entrance channel, whereas the other is centered on the target nucleus in the exit channel. These two methods satisfy the correct initial and final Coulomb boundary conditions in the asymptotic region of scattering, at infinitely large inter-particle separations. Yet, it is presently demonstrated that most of the available experimental data on total cross sections for the double capture from helium by alpha particles distinctly favor the SDS-4B method. This is especially true at intermediate energies. Such energies are critically important in versatile applications under the general umbrella of ion transport in matter, including thermonuclear fusion (plasma physics) and ion therapy (medicine).

The efficacy of intrauterine infusion of platelet rich plasma in women undergoing assisted reproduction: a systematic review and meta-analysis

BackgroundPlatelet-rich plasma (PRP) is an autologous platelet concentration recently used in the reproductive field. Studies had conflicting results regarding its effect on pregnancy outcomes. We aimed to solve the debate on the safety and efficacy of PRP in women undergoing assisted reproduction and assess the influence of covariates on the outcomes of PRP infusion.MethodsWe searched PubMed, Scopus, Cochrane, and Web of Science in May 2023. We included randomized and non-randomized clinical trials as well as cohort studies assessing intrauterine PRP in sub fertile women undergoing assisted reproduction (IVF/ICSI). For the quality assessment, We used the Cochrane Risk of Bias Tool 1, the ROBINS-I tool, and the Newcastle–Ottawa Scale. We pooled the data using RevMan version 5.4.ResultsThe data from 23 studies were pooled. PRP had favorable outcomes compared with the control group on clinical pregnancy rate (RR: 1.84, 95% CI 1.62 to 2.09; P < 0.00001), live birth rate (RR: 1.75, 95% CI: 1.24 to 2.47; P = 0.001), and miscarriages (RR: 0.51, 95% CI: 0.36 to 0.72; P = 0.0002). Women with repeated implantation failure had a significantly improved clinical pregnancy rate (RR: 1.83, 95% CI: 1.49 to 2.24; P < 0.00001), live birth rate (RR:1.83, 95% CI: 1.33 to 2.51; P = 0.002), and miscarriage rate (RR: 0.46, 95% CI: 0.31 to 068; P = 0.0001).ConclusionPRP showed promising results in assisted reproductive techniques. Further large and multicenter RCTs are required to compare the doses of PRP while identifying the specific population with the most benefits from PRP.

Enhancement of fusion reactivity under non-Maxwellian distributions: effects of drift-ring-beam, slowing-down, and kappa super-thermal distributions

Non-Maxwellian distributions of particles are commonly observed in fusion studies, especially for magnetic confinement fusion plasmas. The particle distribution has a direct effect on fusion reactivity, which is the focus of this study. We investigate the effects of three types of non-Maxwellian distributions, namely drift-ring-beam, slowing-down, and kappa super-thermal distributions, on the fusion reactivities of D-T (Deuterium-Trillium) and p-B11 (proton-Boron) using a newly developed program, where the enhancement of fusion reactivity relative to the Maxwellian distribution is computed while keeping the total kinetic energy constant. The calculation results show that for the temperature ranges of interest to us, namely 5–50 keV for D-T and 100–500 keV for p-B11, these non-Maxwellian distributions can enhance the fusion reactivities. In the case of the drift-ring-beam distribution, the perpendicular ring beam velocity leads to decreased enhancement in low temperature range and increased enhancement in high temperature range. This effect is favorable for p-B11 fusion reaction and unfavorable for D-T fusion reaction. This is because the important temperature range for fusion reaction significantly overlaps with the high temperature enhancement range, while the important temperature range for fusion significantly overlaps with the low temperature reduction range. In the slowing-down distribution, the birth speed plays a crucial role in both reactions, and increasing birth speed leads to a shift in the enhancement ranges towards lower temperatures, which is beneficial for both reactions. Finally, the kappa super-thermal distribution results in a relatively large enhancement in the low temperature range with a small high energy power-law index . Overall, this study provides insight into the effects of non-Maxwellian distributions on fusion reactivity and highlights potential opportunities for enhancing fusion efficiency.

Modelling the capacitance of the elongated plasma in tokamak

The capacitance model suitable for the non-circular cross-section plasma is studied based on the capacitance model of the circular cross-section plasma. The coaxial elliptic-torus capacitor property is further derived and used to determine the capacity of non-circular cross-section tokamak plasma, such as EAST (Experimental Advanced Superconducting Tokamak). By testing all the physical terms in this model, we find that the capacitance Cp\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Cp$$\\end{document}) is increasing exponentially with the increase of elongation ratio (k2/k1), while the minor radius ratio (a2/a1) is just reversed at the flat-top of plasma current, and the capacitance property is implicitly included in the H-mode study during the L–H transition. It is noted that Cp-H mode is the least and Cp-I mode is approximately equal to Cp-L mode under the L-mode, I-mode and H-mode regimes based on this capacitance model in EAST. Consequently, it may be integrated into an equivalent circuit of the tokamak transformer or transport computer code of the edge plasma for use in precise simulations of fusion plasma behavior in the future, such as ITER (International Tokamak Experimental Reactor) or BEST (Burning-plasma Experimental Superconducting Tokamak) in China.

Optimization of the collective Thomson scattering diagnostic for the GDT open magnetic trap

The collective Thomson scattering of high-power millimeter-wave radiation on plasma density fluctuations (CTS) is widely used for diagnosing the velocity distribution function of energetic ions in fusion plasma. In this paper, we discuss a non-standard scheme of CTS measurements, which exploits strong refraction of probing and scattered microwave beams when reflecting from the cut-off layer in dense plasma. The scheme may be realized with the existing CTS diagnostic system at the Gas-Dynamic Trap (GDT) facility, a large open magnetic trap operating at Budker Institute (Novosibirsk, Russia). This requires a minor upgrade of the available hardware and essentially increases the range of plasma densities allowed for CTS measurements, as well as its sensitivity and spatial resolution. A detailed study of CTS efficiency for different geometries and plasma conditions at GDT is performed by means of an advanced numerical model that allows for an accurate description of non-Gaussian beam scattering in inhomogeneous plasma. To perform this task, we develop a quasi-optical theory of scattering, which itself may be of general interest.

Stationary Bragg reflection of laser light in inhomogeneous absorbing plasmas inside inertial confinement fusion Hohlraums

Laser-produced plasma in inertial confinement fusion (ICF) Hohlraums are marked with density non-uniformity whose length scale can go down to micrometers. This scale is of the order of the laser wavelength. The WKB approximation, which is classically used in radiation-hydrodynamic codes to compute the laser trajectory, cannot correctly take into account such small-scale inhomogeneity of the plasma. Going beyond this approximation, we predict a novel mechanism for the laser reflection. We show that an electromagnetic plane wave with wave number k resonates with the kB=2 k Fourier component of a multimode perturbation of the background density and generates a reflected wave. It is the first time that this reflection is considered for stationary inhomogeneous ICF plasmas, and the energy absorption is taken into account. This mechanism, which is a form of Bragg reflection, can occur away from the critical surface and generate a drift of the location of the laser absorption. Furthermore, this absorption will be periodically modulated with a kB wave number. The stationary Bragg reflection can explain ongoing discrepancies between experimental and numerical data about laser trajectory and absorption in ICF Hohlraums.

#106 : The Efficacy of Intra-Ovarian Infusion of Autologous Platelet-Rich Plasma in Patients with Poor Ovarian Response: A Systematic Review and Meta-Analysis

Background and Aims: Poor ovarian response (POR) is a pathological condition characterized by a reduced ovarian response to gonadotropin stimulation. This condition presents with a low number of developed follicles during the ovulation induction cycle, low blood estradiol (E2) peak, high gonadotropin dosage, fewer retrieved oocytes, increased cycle cancellation rate, and low clinical pregnancy rate. POR is a significant challenge in assisted reproductive technology. Autologous platelet-rich plasma (PRP) has emerged as a potential therapy for POR, but its efficacy remains controversial. This meta-analysis aims to determine the effect of intraovarian infusion of PRP on ovarian reserve and pregnancy outcomes in patients with POR. Methods: This study was designed as a Meta-analysis. Women diagnosed with POR based on POSEIDON or Bologna criteria were included. Primary outcomes included anti-Müllerian hormone (AMH), antral follicle count (AFC), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and E2 levels, while secondary outcomes were the number of retrieved oocytes and embryo quality. Results: Seven prospective cohort studies involving 202 participants were included. Intra-ovarian infusion of autologous PRP significantly increased AMH (SMD: 0.20, 95% CI: 0.05–0.36; P=0.01), AFC (SMD: 0.92, 95% CI: 0.59–1.25, P&lt;0.05), and E2 (SMD: 3.46, 95% CI: 1.13–5.79; P=0.004) levels in patients with POR. PRP also decreased LH levels in POR (SMD: −1.17, 95% CI: −2.28 to −0.06; P=0.04). However, no statistically significant effect on FSH levels in POR was observed (SMD: −0.17, 95% CI: −0.78 to 0.44; P=0.59). Furthermore, PRP positively impacted the number of retrieved oocytes and embryo quality in IVF cycle patients. Conclusion: This meta-analysis indicates that intra-ovarian injection of autologous PRP can improve ovarian reserve and pregnancy outcomes in patients with POR.

#96 : The Efficacy of Platelet Rich Plasma Therapy in Thin Endometrium Undergoing Frozen Thawed Embryo Transfer in Assisted Reproductive Technology: A Systematic Review and Meta-Analysis

Background and Aim: Endometrium is one of the main factors in implantation and pregnancy. Adequate thickness of the endometrium is crucial for successful embryo implantation. Thin endometrium significantly increases the risk of embryo implantation failure, as the pregnancy rate in women. Intrauterine infusion of platelet rich plasma (PRP) is a new approach that has been suggested for the treatment of thin endometrium. This meta-analysis was conducted systematically to evaluate the efficacy of PRP therapy on endometrial thickness and pregnancy rates. Methods: We conducted a systematic review and meta-analysis of the retrieved randomized controlled trial (RCT). Studies on the intra uterine infusion of PRP in women undergoing frozen thawed embryo transfer (FET) in assisted reproductive technology (ART), identified by conducting a systematic search, using PubMed, Cochrane Central Register of Controlled Trials, and Google Scholar. Data were extracted and analyzed independently using random effects model or common effects model according to heterogeneity. Risk of bias assessment was assessed using RoB 2 tools. Results: Five RCTs involving 377 patients were included in the endometrial thickness outcome. The endometrial thickness between PRP and control group showed a significant probability of increasing endometrial thickness in PRP group (MD 0,83, 95% CI 0,40-1,26, I 2 84%, p&lt;0,01). The rates of chemical pregnancy were significantly higher in PRP group (RR 2,73, 95% CI 1,41-5,27, I 2 51%, p=0,15). The rates of clinical pregnancy were significantly higher in PRP group (RR 1,75, 95% CI 1,29-2,39, I 2 62%, p&lt;0,01). According to RoB evaluation, the overall studie’s quality was minimally bias. Conclusions: In this systematic review, we concluded that PRP was an effective therapy to increase endometrial thickness and as alternative treatment strategy for thin endometrium undergoing FET in ART. Although this study retrieved some RCT, we suggested that additional RCT were needed to increase the power of study.

#344 : Intrauterine Platelet-Rich Plasma and Peripheral Blood Mononuclear Cells Doubles Clinical Pregnancy Rate in Recurrent Implantation Failure: Efficacies Obscured by Non-Randomized Controlled Trials - Two Meta-Analyses

Background and Aims: Recurrent implantation failure (RIF) is a frustrating problem confronting prospective mothers following embryo transfer. Two promising intrauterine immunotherapies, plasma-rich plasma (PRP) and peripheral blood mononuclear cells (PBMC) infusions, have been investigated with mixed results, leaving experts querying if these are “add-on treatments getting out of hand?”. The current meta-analyses aim to identify the source of the conflicting evidence and determine the true efficacy of IU-PRP and IU-PBMC. Method: A systematic search was conducted on April 30, 2023, using OVID Medline and Embase. Eligible articles pertaining to the efficacy of IU-PRP and IU-PBMC upon clinical pregnancy in fertility research were retrieved. Risk ratios and confidence intervals were calculated via the random effects model (Cochrane Review Manager). Results: IU-PRP Pooled data: 26 studies, 3016 participants, RR=1.64(1.41-1.90), X2=0.009, I2=44%, showing significant heterogeneity. RCTs: 15 studies, 1557 participants with RR=2.02(1.71-2.39), X2p=0.43, I2=2%. Non-RCTs: 11 studies, 1459 participants with RR=1.34(1.19-1.52), X2p=0.39, I2=5%. Subgroup analysis: homogenous effect sizes with non-overlapping 95%CI, X2p=0.0001, I2=93.4%. (Figure 1) IU-PBMC RCTs: 6 studies, 652 participants, RR=2.17(1.71-2.74), X2p=0.92, I2=0%. Non-RCTs: 6 studies, 866 participants, RR=1.43(1.20-1.70), X2p=0.69, I2=0%. Subgroup analysis: homogenous effect sizes with non-overlapping 95%CI, X2p=0.005, I2=87.4%. (Figure 2) Conclusion: Non-RCTs provide savings in cost and time that can lead to early awareness of innovative therapies. This may be counterproductive in RIF research due to flawed non-randomized controls: retrospective cohorts, women refusing consent to therapy, women without RIF or having first IVF attempt. Intervention groups therefore may have a higher baseline risk of failure, resulting in apples-to-oranges comparisons that obscure the actual efficacy. Randomization is fundamental in reducing patient selection bias and the RCTs in these analyses demonstrated that IU-PRP and IU-PBMC doubles the clinical pregnancy rate in RIF patients. A debate into the role of non-RCTs in RIF research is essential to avoid a potential systemic problem.

Value of Intrauterine Autologous Platelet-Rich Plasma Therapy on Endometrial Receptivity: A Literature Review.

Endometrial receptivity is an important factor that influences embryo implantation. Thus, it is important to identify an applicable approach to improve endometrial receptivity in women undergoing assisted reproductive technology. Recently, growing evidence has indicated that intrauterine platelet-rich plasma (PRP) infusion is an effective method to obtain a satisfactory reproductive outcome by increasing endometrial thickness and improving endometrial receptivity. Therefore, the present review aims to outline the possible mechanisms of PRP on endometrial receptivity and summarize the present literature on the effects of PRP therapy in improving endometrial receptivity.

The theory of kinetic effects on resistive wall mode stability in tokamaks

Tokamak fusion plasmas benefit from high pressures but are then susceptible to modes of instability. These magnetohydrodynamic (MHD) modes are macroscopic distortions of the plasma, but certain collective motions of individual particles can provide stabilizing effects opposing them. The presence of a resistive wall slows the mode growth, converting a kink to a resistive wall mode (RWM). A kinetic MHD model includes Maxwell's equations, ideal MHD constraints, and kinetic effects included through the pressure tensor, calculated with the perturbed drift-kinetic distribution function of the particles. The kinetic stabilizing effects on the RWM arise through resonances between the plasma rotation and particle drift motions: precession, bounce, and transit. A match between particle motions and the mode allows efficient transfer of energy that would otherwise drive the growth of the mode, thus damping the growth. The first approach to calculating RWM stability is to write a set of equations for the complex mode frequency in terms of known quantities and then to solve the system. The “energy principle” approach, which has the advantage of clarity in distinguishing the various stabilizing and destabilizing effects, is to change the force balance equation into an equation in terms of changes of kinetic and potential energies, and then to write a dispersion relation for the mode frequency in terms of those quantities. These methods have been used in various benchmarked codes to calculate kinetic effects on RWM stability. The theory has illuminated the important roles of plasma rotation, energetic particles, and collisions in RWM stability.

Fractal Escape Basins for Magnetic Field Lines in Fusion Plasma Devices

Fractal Escape Basins for Magnetic Field Lines in Fusion Plasma Devices