Utility of plasma D-dimer for diagnosis of venous thromboembolism after hepatectomy

BACKGROUND Venous thromboembolism(VTE)is a potentially fatal complication of hepatectomy.The use of postoperative prophylactic anticoagulation in patients who have undergone hepatectomy is controversial because of the risk of postoperative bleeding.Therefore,we hypothesized that monitoring plasma D-dimer could be useful in the early diagnosis of VTE after hepatectomy.AIM To evaluate the utility of monitoring plasma D-dimer levels in the early diagnosis of VTE after hepatectomy.METHODS The medical records of patients who underwent hepatectomy at our institution between January 2017 and December 2020 were retrospectively analyzed.Patients were divided into two groups according to whether or not they developed VTE after hepatectomy,as diagnosed by contrast-enhanced computed tomography and/or ultrasonography of the lower extremities.Clinicopathological factors,including demographic data and perioperative D-dimer values,were compared between the two groups.Receiver operating characteristic curve analysis was performed to determine the D-dimer cutoff value.Univariate and multivariate analyses were performed using logistic regression analysis to identify significant predictors.RESULTS In total,234 patients who underwent hepatectomy were,of whom(5.6%)were diagnosed with VTE following hepatectomy.A comparison between the two groups showed significant differences in operative time(529 vs 403 min,P=0.0274)and blood loss(530 vs 138 mL,P=0.0067).The D-dimer levels on postoperative days(POD)1,3,5,7 were significantly higher in the VTE group than in the non-VTE group.In the multivariate analysis,intraoperative blood loss of>275 mL[odds ratio(OR)=5.32,95%confidence interval(CI):1.05-27.0,P=0.044]and plasma D-dimer levels on POD 5≥21μg/mL(OR=10.1,95%CI:2.04-50.1,P=0.0046)were independent risk factors for VTE after hepatectomy.CONCLUSION Monitoring of plasma D-dimer levels after hepatectomy is useful for early diagnosis of VTE and may avoid routine prophylactic anticoagulation in the postoperative period.

Elevated preoperative plasma D-dimer dose not adversely affect survival of gastric cancer after gastrectomy with curative intent: A propensity score analysis

Objective： Elevated plasma D-dimer has been reported to be associated with advanced tumor stage and poor survival in several types of malignancies. The purpose of this study was to assess the potential impact of preoperative plasma D-dimer level（PDL） on overall survival（OS） of gastric cancer（GC） patients undergoing curative surgery by applying propensity score analysis.Methods： A total of 1,025 curatively resected GC patients in Tianjin Medical University Cancer Institute ＆Hospital were enrolled. Patients were categorized into two groups based on preoperative PDL： the elevated group（EG） and the normal group（NG）. To overcome bias due to the different distribution of covariates for the two groups, a one-to-one match was applied using propensity score analysis, after matching, prognostic factors were analyzed.Results： In analysis for the whole study series, patients in the EG were more likely to have a larger proportion of tumor size ≥5 cm（67.5% vs. 55.8%, P=0.006）, elder mean age（64.0±10.8 years vs. 60.5±11.6 years, P〈0.001） and advanced tumor（T）, node（N）, and TNM stage. Patients with elevated PDL demonstrated a significantly lower 5-year OS than those with normal PDL（27.0% vs. 42.6%, P〈0.001）, however, the PDL was not an independent prognostic factor for OS in multivariate analysis [hazard ratio： 1.13, 95% confidence interval（95% CI）： 0.92–1.39,P=0.236]. After matching, 163 patients in the EG and 163 patients in the NG had the same characteristics. The 5-year OS rate for patients in the EG was 27.0% compared with 25.8% for those in the NG（P=0.809, log-rank）.Conclusions： The poor prognosis of GC patients with elevated preoperative PDL was due to the advanced tumor stage and elder age rather than the elevated D-dimer itself.

CLINICAL SIGNIFICANCE OF PLASMA D-DIMER LEVELS IN PATIENTS WITH ESOPHAGEAL CANCER

Objective: To investigate the clinical significance of the changes of D-dimer levels in patients with esophageal cancer. Methods: The plasma levels of D-dimer were measured pre-and postoperatively in 33 patients with esophageal cancer and 30 healthy subjects served as controls by the method of quantitative enzyme-linked immunosorbent assay (ELISA). Results: The mean preoperative plasma levels of D-dimer in the patients with esophageal cancer (1.98 mg/L±0.34 mg/L) were significantly higher than that of controls (0.33 mg/L±0.12 mg/L) (P<0.01). The D-dimer levels were remarkably elevated on the 1st day after operation (2.41 mg/L±0.55 mg/L) (P<0.01). On the 3rd day the level of D-dimer began to stepwise descend and on the 14th day near to control. The preoperative levels of D-dimer were significantly correlated with the tumor size but had no association with tumor location. A stepwise increase in the mean DD levels was found with the tumor stage. Conclusion: The hypercoagulation and fibrinolysis have occurred in patients with esophageal cancer. The operative trauma could enhance the fibrinolysis in the patients with esophageal cancer. The measurement of the preoperative DD levels is considered to be useful for the preoperative staging of esophageal cancer.

The relationship between level of plasma D-dimer and survival time in metastatic gastric cancer patients

Objective:The principal purpose of this study was to determine the relationship between level of plasma D-dimer and survival time in metastatic gastric cancer patients.Methods:We retrospectively collected the data of plasma D-dimer in metastatic gastric cancer patients admitted in our Department (Department of Oncology,The Affiliated Changzheng Hospital,The Second Military Medical University,Shanghai,China) from October 2006 to October 2008 and analyzed the relationship between level of plasma D-dimer and survival time along with other clinicopathologic parameters.Results:A total of 82 patients were studied in our research,52 were males and 30 females,and the mean age was 57 years.The 48 cases had a normal plasma D-dimer level (<300μg/L) and 34 had a high plasma D-dimer level (≥300μg/L).In the normal and high plasma D-dimer level groups,the mean survival times were 10.9 (95% CI:9.8-12.2) months and 6.8(95% CI:4.4-7.6) months respectively,and the difference was statistically significant.Conclusion:Metastatic gastric cancer patients with high plasma D-dimer level had significantly shorter survival time than those with normal plasma D-dimer level.Level of plasma D-dimer can be referred as a potential predictor in metastatic gastric cancer patients.

Plasma D-dimer level in early and late-onset neonatal sepsis

BACKGROUND Neonatal sepsis is a life-threatening disease.Early diagnosis is essential,but no single marker of infection has been identified.Sepsis activates a coagulation cascade with simultaneous production of the D-dimers due to lysis of fibrin.Ddimer test reflects the activation of the coagulation system.AIM To assess the D-dimer plasma level,elaborating its clinicopathological value in neonates with early-onset and late-onset neonatal sepsis.METHODS The study was a prospective cross-sectional study that included ninety neonates;divided into three groups:Group I:Early-onset sepsis(EOS);Group II:Late-onset sepsis(LOS);and GroupⅢ:Control group.We diagnosed neonatal sepsis according to our protocol.C-reactive protein(CRP)and D-dimer assays were compared between EOS and LOS and correlated to the causative microbiological agents.RESULTS D-dimer was significantly higher in septic groups with a considerably higher number of cases with positive D-dimer.Neonates with LOS had substantially higher levels of D-dimer than EOS,with no significant differences in CRP.Neonates with LOS had a significantly longer hospitalization duration and higher gram-negative bacteriemia and mortality rates than EOS(P<0.01).Gramnegative bacteria have the highest D-dimer levels(Acinetobacter,Klebsiella,and Pseudomonas)and CRP(Serratia,Klebsiella,and Pseudomonas);while gram-positive sepsis was associated with relatively lower levels.D-dimer had a significant negative correlation with hemoglobin level and platelet count;and a significant positive correlation with CRP,hospitalization duration,and mortality rates.The best-suggested cut-off point for D-dimer in neonatal sepsis was 0.75 mg/L,giving a sensitivity of 72.7%and specificity of 86.7%.The D-dimer assay has specificity and sensitivity comparable to CRP in the current study.CONCLUSION The current study revealed a significant diagnostic value for D-dimer in neonatal sepsis.D-dimer can be used as an adjunct to other sepsis markers to increase the sensitivity and specificity of diagnosing neonatal sepsis.

Estimation and Assessment of Plasma D-Dimer Levels in HIV Patients

Background: The elevation of plasma D-dimer levels is fully described and associated with the increase of the mortality of patients with HIV. The present study was aimed to estimate and assess the plasma D-dimer levels in HIV patient. Material and Methods: A case control study done in May 2015. A total of 100 subjects were enrolled in this study;50 were patients professionally diagnosed by HIV;25 (50%) were males and 25 (50%) were females;their mean age is 35 years. Further 50 normal healthy individuals as normal control group: their gender and age were matched with patient groups. The platelets poor plasma (PPP) was immediately prepared from citrated blood, then the plasma D-dimer level was measured using (MISPA-i2 Reagent) Switzerland. Data were analyzed using statistical packing for social sciences program (SPSS) 20. Results: The D-dimer levels was significantly higher in patient with HIV compared with the normal healthy control group (Mean and STD 502.2 ± 287.8 vs 251.8 ± 152.7 P. value 0.01). Conclusion: The D-dimer level was significantly higher in patient with HIV compared with those in normal healthy control group.

Analysis of the Role of D-Dimer,Interleukin-6,and Interleukin-18 in Differential Diagnosis of Pediatric Refractory Mycoplasma pneumoniae Pneumonia

Objective:To analyze the value of D-dimer(D-D),interleukin-6(IL-6),and IL-18 in the differential diagnosis of children with refractory Mycoplasma pneumoniae pneumonia(RMPP).Methods:The medical records of 92 children with Mycoplasma pneumoniae pneumonia(MPP)treated in the hospital were selected for retrospective analysis from January 2023 to January 2024.After comprehensive examinations such as computed tomography examination of the chest,48 children with general Mycoplasma pneumoniae pneumonia(GMPP)were put in the GMPP group and 44 children with RMPP were grouped in the RMPP group.The IL-6,IL-18,and D-D levels were compared between the two groups,and the receiver operating characteristic(ROC)curves were plotted to analyze their value for differential diagnosis of RMPP.Results:The levels of IL-6,IL-18,and D-D in the RMPP group were higher than those in the GMPP group(P<0.05);the ROC curves showed that the specificity of the differential diagnosis of IL-6,IL-18,and D-D was higher,and their diagnostic value was significant.Conclusion:Determination of IL-6,IL-18,and D-D levels in children with MPP can further diagnose the children’s condition,which can help physicians formulate targeted treatment plans,and is of great significance to the improvement of the children’s condition,which is worthy of attention.

Storage time affects the level and diagnostic efficacy of plasma biomarkers for neurodegenerative diseases

Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative diseases.However,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°C.We aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large cohort.Plasma samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline project.These samples were stored at-80°C for up to 6 years before being used in this study.Our results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage time.However,the level of total tau showed a negative correlation with sample storage time.Notably,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage time.This was not observed in individuals with cognitive impairment.Consequently,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage time.Therefore,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's disease.Furthermore,in cohort studies,it is important to consider the impact of storage time on the overall results.

Effect of electroacupuncture at "Bǎihuì"(百会GV 20) and "Shuǐgōu"(水沟GV 26) acupoints on the contents of plasma D-dimer and fibrinogen in rats with acute cerebral infarction

Objective To investigate the mechanisms of electroacupuncture （EA） at ＂Baihui＂ （百会 GV 20） and ＂Shuigou＂ （水沟 GV 26） for treating cerebral infarction. Methods Forty healthy SD rats were randomly divided into model group （n = 10）, EA group （n = 10）, normal group （n = 10）, and sham operation group （n = 10）. The model of acute cerebral infarction was established by blocking the middle cerebral artery with an intraluminal thread. EA was applied at ＂Baihui＂ （百会 GV 20） and ＂Shuigou＂ （水沟GV 26） in the rats of EA group after the models were developed. The contents of D-dimer （D-D） and fibrinogen （Fib） were measured in each group. Results The contents of D-D and Fib increased signifi- cantly in model group as compared with normal and sham operation groups, respectively （P〈0.01）, and they decreased significantly in EA group as compared with model group （P〈0.01）. Conclusion EA can ob-viously decrease the contents of D-D and Fib, improve abnormal fibrinolysis, lower blood viscosity and ameliorate cerebral blood circulation in the rats with acute cerebral infarction.

Correlation analysis between plasma D-dimer levels and orthopedic trauma severity

Background The correlation between the plasma D-dimer level and deep vein thrombosis has not been conclusive in various studies. The aim of this research was to study the relationship between plasma D-dimer levels and the severity of orthopedic trauma by retrospective examination of orthopedic trauma cases. Methods Clinically acute trauma and non-acute trauma patients were selected and their plasma D-dimer levels were measured. Plasma D-dimer levels in patients of these two groups were compared. The relationship between the plasma D-dimer level and the severity of the trauma was also studied. Results There were 548 cases in the acute trauma group and 501 cases in the non-acute trauma group. The levels of plasma D-dimer were significantly higher in the acute trauma group than in the non-acute trauma group （P 〈0.01）. In the acute trauma group, the correlation between the D-dimer level and the number of fractures was a positive linear correlation （r=0.9532）. Conclusions Elevated plasma D-dimer is common in trauma patients. The D-dimer level and the number of fractures in the trauma patients are closely correlated. D-dimer is not only an indicator for the diagnosis of deep vein thrombosis and pulmonary embolus, but also an indicator of the severity of trauma in acute trauma patients.

Serum inflammatory markers in children with Mycoplasma pneumoniae pneumonia and their predictive value for mycoplasma severity

BACKGROUND Mycoplasma pneumoniae pneumonia(MPP)significantly impacts pediatric health,necessitating markers for early severe disease identification.AIM To investigate the correlation between serum inflammatory marker and the severity of MPP in children.METHODS A prospective study was carried out from January 2023 to November 2023.A total of 160 children with MPP who underwent treatment were selected:80 had severe MPP and 80 had mild MPP.Clinical and laboratory data were collected at the time of hospital admission and during hospitalization.Receiver operating characteristic curves were utilized to assess the diagnostic and prognostic for severe MPP.RESULTS Fever duration and length of hospitalization in pediatric patients with severe MPP exceeded those with mild MPP.The incidence of pleural effusion,lung consolidation,and bronchopneumonia on imaging was markedly elevated in the severe MPP cohort compared to the mild MPP cohort.In contrast to the mild cohort,there was a notable increase in C-reactive protein(CRP),procalcitonin(PCT),erythrocyte sedimentation rate,lactic dehydrogenase,D-dimer,and inflammatory cytokines[interleukin(IL)-6,IL-8,IL-10 and tumor necrosis factor(TNF)-α]in the severe MPP group were significantly higher.CONCLUSION Serum inflammatory markers(CRP,PCT,IL-6,D-dimer,IL-10 and TNF-α)were considered as predictors in children with severe MPP.

Plasma‐oxidized 2D MXenes subnanochannel membrane for high‐performance osmotic energy conversion

Nanofluidic channels inspired by electric eels open a new era of efficient harvesting of clean blue osmotic energy from salinity gradients.Limited by less charge and weak ion selectivity of the raw material itself,energy conversion through nanofluidic channels is still facing considerable challenges.Here,a facile and efficient strategy to enhance osmotic energy harvesting based on drastically increasing surface charge density of MXenes subnanochannels via oxygen plasma is proposed.This plasma could break Ti–C bonds in the MXenes subnanochannels and effectively facilitate the formation of more Ti–O,C═O,O–OH,and rutile with a stronger negative charge and work function,which leads the surface potential of MXenes membrane to increase from 205 to 430 mV.This significant rise of surface charge endows the MXenes membrane with high cation selectivity,which could make the output power density of the MXenes membrane increase by 248.2%,reaching a high value of 5.92Wm^(−2) in the artificial sea‐river water system.Furthermore,with the assistance of low‐quality heat at 50℃,the osmotic power is enhanced to an ultrahigh value of 9.68Wm^(−2),which outperforms those of the state‐of‐the‐art two‐dimensional(2D)nanochannel membranes.This exciting breakthrough demonstrates the enormous potential of the facile plasma‐treated 2D membranes for osmotic energy harvesting.

Spark Plasma Sintering of Mg-based Alloys:Microstructure,Mechanical Properties,Corrosion Behavior,and Tribological Performance

Within the past ten years,spark plasma sintering(SPS)has become an increasingly popular process for Mg manufacturing.In the SPS process,interparticle diffusion of compressed particles is rapidly achieved due to the concept of Joule heating.Compared to traditional and additive manufacturing(AM)techniques,SPS gives unique control of the structural and microstructural features of Mg components.By doing so,their mechanical,tribological,and corrosion properties can be tailored.Although great advancements in this field have been made,these pieces of knowledge are scattered and have not been contextualized into a single work.The motivation of this work is to address this scientific gap and to provide a groundwork for understanding the basics of SPS manufacturing for Mg.To do so,the existing body of SPS Mg literature was first surveyed,with a focus on their structural formation and degradation mechanisms.It was found that successful Mg SPS fabrication highly depended on the processing temperature,particle size,and particle crystallinity.The addition of metal and ceramic composites also affected their microstructural features due to the Zener pinning effect.In degradative environments,their performance depends on their structural features and whether they have secondary phased composites.In industrial applications,SPS'd Mg was found to have great potential in biomedical,hydrogen storage,battery,automotive,and recycling sectors.The prospects to advance the field include using Mg as a doping agent for crystallite size refinement and using bulk metallic Mg-based glass powders for amorphous SPS components.Despite these findings,the interactions of multi-composites on the processing-structure-property relationships of SPS Mg is not well understood.In total,this work will provide a useful direction in the SPS field and serve as a milestone for future Mg-based SPS manufacturing.

Plasma-assisted aerogel interface engineering enables uniform Zn^(2+)flux and fast desolvation kinetics toward zinc metal batteries

The poor reversibility of Zn anodes induced by dendrite growth,surface passivation,and corrosion,severely hinders the practical applicability of Zn metal batteries.To address these issues,a plasmaassisted aerogel(PAG)interface engineering was proposed as efficient ion transport modulator that can simultaneously regulate uniform Zn^(2+)flux and desolvation behavior during battery operation.The PAG with ordered mesopores acted as an ion sieve to homogenize Zn deposition and accelerate Zn^(2+)flux,which is favorable for corrosion resistance and dendrite suppression.Importantly,the plasma-assisted aerogel with abundant hydrophilic groups can facilitate the desolvation kinetics of Zn^(2+)due to the multiple hydrogen-bonding interaction with the activated water molecules,thus accelerating the Zn^(2+)migration kinetics.Consequently,the Zn/Zn cell assembled with PAG-modified separator demonstrates stable plating and stripping behavior(over 1400 h at 1 mA cm^(-2))and high Coulombic efficiency(99.8%at1 mA cm^(-2)after 1100 cycles),and the Zn‖MnO_(2)full cell shows excellent long-term cycling stability and maintains a high capacity of 154.9 mA h g^(-1)after 1000 cycles at 1 A g^(-1).This study provides a feasible approach for the large-scale fabrication of aerogel functionalized separators to realize ultra-stable Zn metal batteries.

Study of plasma parameters of coaxial plasma source using triple Langmuir probe and Faraday cup diagnostics

Coaxial plasma guns are a type of plasma source that produces plasma which propagates radially and axially controlled by the shape of the ground electrode, which has attracted much interest in several applications. In this work, a 120° opening angle of CPG nozzle is used as a plasma gun configuration that operates at the energy of 150 J. The ionization of polyethylene insulator between the electrodes of the gun produces a cloud of hydrogen and carbon plasma.The triple Langmuir probe and Faraday cup are used to measure plasma density and plasma temperature. These methods are used to measure the on-axis and off-axis plasma divergence of the coaxial plasma gun. The peak values of ion densities measured at a distance of 25 mm on-axis from the plasma gun are(1.6±0.5)×10^(19)m^(-3)and(2.8±0.6)×10^(19)m^(-3)for hydrogen and carbon plasma respectively and the peak temperature is 3.02±0.5 eV. The mean propagation velocity of plasma is calculated using the transit times of plasma at different distances from the plasma gun and is found to be 4.54±0.25 cm/μs and 1.81±0.18 cm/μs for hydrogen and carbon plasma respectively. The Debye radius is obtained from the measured experimental data that satisfies the thin sheath approximation. The shot-to-shot stability of plasma parameters facilitates the use of plasma guns in laboratory experiments. These types of plasma sources can be used in many applications like plasma opening switches, plasma devices, and as plasma sources.

Effects of external parameters on plasma characteristics and uniformity in a dual cylindrical inductively coupled plasma

The dual cylindrical inductively coupled plasma source,compared to the conventional structure of inductively coupled plasma source,can significantly improve the uniformity of plasma.It has an enhanced potential for application in processes,such as etching and ashing.A uniform plasma can be obtained by allowing the remote plasma from the upper chamber modulate the main plasma generated in the lower chamber.In this study,a fluid model was employed to investigate a dual cylindrical inductively coupled Ar/O_(2)discharge.The effects of external parameters on electron density,electron temperature,O atomic density,and plasma uniformity in the main chamber were studied,and the reasons were analyzed.The results of this study show that remote power can control the plasma uniformity and increase the plasma density in the main chamber.As the remote power increased,plasma uniformity improved initially and then deteriorated.The main power affected the plasma density at the edge of the main chamber and can modulate the plasma density in the main chamber.The gas pressure affected both the uniformity and density of the plasma.As the gas pressure increased,the plasma uniformity deteriorated,but the free radical density improved.

The multi-peak point phenomenon of broadband microwave reflection caused by inhomogeneous plasma

During spacecraft re-entry,the challenge of measuring plasma sheath parameters directly contributes to difficulties in addressing communication blackout.In this work,we have discovered a phenomenon of multiple peaks in reflection data caused by the inhomogeneous plasma.Simulation results show that the multi-peak points fade away as the characteristic frequency is approached,resembling a series of gradually decreasing peaks.The positions and quantities of these points are positively correlated with electron density,yet they show no relation to collision frequency.This phenomenon is of significant reference value for future studies on the spatial distribution of plasmas,particularly for using microwave reflection signals in diagnosing the plasma sheath.

Final results of the first phase of the PROTO-SPHERA experiment: obtainment of the full current stable screw pinch and first evidences of the jet + torus combined plasma configuration

In astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 225], on the other hand, in laboratory plasma experiments the electromagnetic boundary conditions become a major problem in the set-up of the machine that produces the plasma, an issue that has to be investigated step by step and to be modified and adapted with great patience, in particular in the case of an innovative plasma confinement experiment. The PROTO-SPHERA machine [Alladio F et al 2006 Nucl. Fusion 46 S613] is a magnetic confinement experiment, that emulates in the laboratory the jet + torus plasma configurations often observed in astrophysics: an inner magnetized jet of plasma centered on the(approximate) axis of symmetry and surrounded by a magnetized plasma torus orthogonal to this jet. The PROTO-SPHERA plasma is simply connected, i.e., no metal current conducting rod is linked to the plasma torus, while instead it is the inner magnetized plasma jet(in the following always called the plasma centerpost) that is linked to the torus. It is mandatory that no spurious plasma current path modifies the optimal shape of the plasma centerpost. Moreover, as the plasma torus is produced and sustained, in absence of any applied inductive electric field, by the inner plasma centerpost through magnetic reconnections [Taylor J B and Turner M F 1989 Nucl.Fusion 29 219], it is required as well that spurious current paths do not surround the torus on its outboard, in order not to lower the efficiency of the magnetic reconnections that maintain the plasma torus at the expense of the plasma centerpost. Boundary conditions have been corrected,up to the point that the first sustainment in steady state has been achieved for the combined plasma.

Experimental confirmation of the linear relation between plasma current and external vertical magnetic field in EXL-50 spherical torus energetic electron plasmas

A three-fluid equilibrium plasma with bulk plasma and energetic electrons has been observed on the Xuanlong-50(EXL-50) spherical torus, where the energetic electrons play a crucial role in sustaining the plasma current and pressure. In this study, the equilibrium of a multi-fluid plasma was investigated by analyzing the relationship between the external vertical magnetic field(B_(V)),plasma current(I_(p)), the poloidal ratio(β_(p)) and the Shafranov formula. Remarkably, our research demonstrates some validity of the Shafranov formula in the presence of multi-fluid plasma in EXL-50 spherical torus. This finding holds significant importance for future reactors as it allows for differentiation between alpha particles and background plasma. The study of multi-fluid plasma provides a significant reference value for the equilibrium reconstruction of burning plasma involving alpha particles.

Effect of matrix thermal properties on laser-induced plasma

The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.