Capillary Plasma Research Articles

Emittance preserving thin film plasma mirrors for GeV scale laser plasma accelerators

Laser-plasma accelerators (LPAs) now routinely produce electron beams with GeV energies over acceleration lengths on the order of a few centimeters. This capability and the demonstration of multistage coupling make LPAs promising for numerous applications. However, beam quality preservation in multistage accelerators remains an obstacle because of the need to separate the laser pulse from the electron beam. Plasma mirrors can be used to redirect the laser pulse, but their substrate thickness threatens to substantially degrade the electron beam emittance. Ultrathin ($\ensuremath{\sim}20\text{ }\text{ }\mathrm{nm}$) liquid crystal (LC) plasma mirrors are an excellent candidate to address this challenge. This work investigates the robustness of thin LC plasma mirrors in the presence of capillary discharge plasma and an auxiliary heater laser. We find they can be operated $\ensuremath{\sim}10\text{ }\text{ }\mathrm{cm}$ from the capillary exit when a heater laser is used. We then performed a normalized emittance measurement enabled using a 20 nm LC plasma mirror to protect electron beam optics after the LPA. The emittance contribution from scattering through the plasma mirror is calculated to be of order 100 nm, much less than the measured emittance of $4.0\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. Finally, we develop a model to calculate plasma mirror performance based on the laser polarization and intensity, and plasma mirror thickness.

Study of Heterogeneous Plasma Created by Magneto-Plasma Compressor and Erosive Capillary Discharge

Magneto-plasma compressor with a pulsed capillary erosive plasma generator (MPC-EP) has been designed, manufactured and tested at the first time. This MPC-EP was used to study the physical properties of a high-energy long-lived heterogeneous plasma (ELHP) created by pulsed capillary erosive plasma generator (EP) at the wide range of pressure and temperature. The results of measurements of the parameters of the shock wave created by the MPC-EP, as well as optical spectroscopy and soft X-ray spectroscopy are presented.

Lung Ultrasound Findings of Patients with Dengue Infection: A Prospective Observational Study.

Lung ultrasound (LUS) is a more sensitive method of detecting pathological pulmonary changes than chest X-ray. Therefore, LUS for patients with dengue could be an important tool for the early detection of pleural effusions and pulmonary edema signifying capillary plasma leakage, which is the hallmark of severe dengue pathophysiology. We conducted a prospective observational study of pulmonary changes identifiable with LUS in dengue patients admitted to the Hospital for Tropical Diseases in Mahidol University, Bangkok, and the Bamrasnaradura Infectious Diseases Institute, Nonthaburi, Thailand. The LUS findings were described according to standard criteria, including the presence of A, B1, B2, and C patterns in eight chest regions and the presence of pleural effusions. From November 2017 to April 2018, 50 patients with dengue were included in the study. LUS was performed during the febrile phase for nine patients (18%) and during the critical-convalescence phase for 41 patients (82%). A total of 33 patients (66%) had at least one abnormality discovered using LUS. Abnormal LUS findings were observed more frequently during the critical-convalescence phase (N = 30/41; 73%) than during the febrile phase (N = 3/9; 33%) (P = 0.047). Abnormal aeration patterns were observed in 31 patients (62%). Only B patterns with only multiple B lines were observed in 21 patients (42%); of these patients, three had already exhibited B patterns during the febrile phase (N = 3). C patterns (N = 10; 24%), pleural effusion (N = 10; 24%), and subpleural abnormalities (N = 11; 27%) were observed only during the critical-convalescence phase. LUS can detect signs of capillary leakage, including interstitial edema and pleural effusions, early during the course of dengue.

Pulsed Discharge Characteristics of a Semicombustible Plasma Generator for ETC Launchers

A semicombustible plasma generator (SCPG), including a special tubular semicombustible medium, is introduced to improve the discharge property of the plasma generator and enhance the electrothermal–chemical (ETC) launch efficiency. The new structure of SCPG is mixed with both capillary plasma generator (CPG) and discharge rod plasma generator (DRPG). After the design and simulation, the electrical characteristics of this SCPG are discussed with both static test and dynamic tests. Results show that the SCPG is a resistive load with low inductance, which has stable and consistent electrical parameters. With the increase of discharge voltage, the peak current of SCPG is increased and the equivalent resistance of SCPG is decreased. The peak voltage is nearly 1.3 kV and the pulse current bottom width is more than 3.5 ms. Compared with the DRPG, the load characteristics of SCPG are in a stable and consistent trend during the pulsed discharge process as the same as DRPG. Also, the SCPG has longer stable working times and better stable working parameters and performance. This SCPG will promote the interaction between the plasma and propellants in the chamber.

Reduced model of plasma evolution in hydrogen discharge capillary plasmas.

A model describing the evolution of the average plasma temperature inside a discharge capillary device including Ohmic heating, heat loss to the capillary wall, and ionization and recombination effects is developed. Key to this approach is an analytic quasistatic description of the radial temperature variation which, under local thermal equilibrium conditions, allows the radial behavior of both the plasma temperature and the electron density to be specified directly from the average temperature evolution. In this way, the standard set of coupled partial differential equations for magnetohydrodynamic (MHD) simulations is replaced by a single ordinary differential equation, with a corresponding gain in simplicity and computational efficiency. The on-axis plasma temperature and electron density calculations are benchmarked against existing one-dimensional MHD simulations for hydrogen plasmas under a range of discharge conditions and initial gas pressures, and good agreement is demonstrated. The success of this simple model indicates that it can serve as a quick and easy tool for evaluating the plasma conditions in discharge capillary devices, particularly for computationally expensive applications such as simulating long-term plasma evolution, performing detailed input parameter scans, or for optimization using machine-learning techniques.

The Accuracy of Continuous Glucose Monitoring in the Medical Intensive Care Unit.

To assess the accuracy of continuous glucose monitoring (CGM) in medical intensive care unit (MICU) patients. A Medtronic Enlite® sensor accuracy was assessed versus capillary blood glucose (CBG) and plasma glucose (PG) using the mean absolute relative difference (MARD), surveillance error grid (SEG) analysis and modified Bland-Altman plots. Using CBG as a reference, MARD was 6.6%. Overall, 99.7% of the CGM readings were within the "no risk" zone. No significant differences in accuracy were seen within vasopressor subgroups. Using PG as the reference, MARD was 8.8%. The surveillance error grid analysis showed 95.2% of glucose readings were within the "no risk" zone. There were no device-related adverse events. The CGM sensor showed acceptable accuracy in MICU patients, regardless of vasopressor use.

Development of a photoacoustic microscopy technique to assess peritubular capillary function and oxygen metabolism in the mouse kidney

Microcirculatory changes and oxidative stress have long been associated with acute kidney injury. Despite substantial progress made by two-photon microscopy of microvascular responses to acute kidney injury in rodent models, little is known about the underlying changes in blood oxygen delivery and tissue oxygen metabolism. To fill this gap, we developed a label-free kidney imaging technique based on photoacoustic microscopy, which enables simultaneous quantification of hemoglobin concentration, oxygen saturation of hemoglobin, and blood flow in peritubular capillaries invivo. Based on these microvascular parameters, microregional oxygen metabolism was quantified. We demonstrated the utility of this technique by studying kidney hemodynamic and oxygen-metabolic responses to acute kidney injury in mice subject to lipopolysaccharide-induced sepsis. Dynamic photoacoustic microscopy of the peritubular capillary function and tissue oxygen metabolism revealed that sepsis induced an acute and significant reduction in peritubular capillary oxygen saturation of hemoglobin, concomitant with a marked reduction in kidney ATP levels and contrasted with nominal changes in peritubular capillary flow and plasma creatinine. Thus, our technique opens new opportunities to study microvascular and metabolic dysfunction in acute and chronic kidney diseases.

Community-level screening for type 2 diabetes risk in Mexicans living in Colorado

Introduction: Many Mexican immigrants to the US are medically underserved and have a higher risk for type 2 diabetes; early identification of risk factors can prompt referrals to lifestyle changes and primary care in this population. We used a cross-sectional study design to assess diabetes risk using an existing community partnership, a public health professional, and a lay health promoter model to identify individuals at high risk for diabetes without imposing tests that are difficult to perform or sustain in a community setting. Materials and Methods: Between January 1st, 2018, and December 31st, 2019, a community-based approach for type 2 diabetes-risk screening was conducted by lay health workers using a standard protocol including an educational component, the FINDRISC questionnaire, and capillary plasma glucose criteria. Basic descriptive statistics were obtained for demographic, lifestyle, and diabetes risk factors. Results: Our team screened 783 adult individuals (444 females and 339 males) for type 2 diabetes risk. 29% of participants (35.6% of females and 20.6% of males) were at high risk of type 2 diabetes because they had FINDRISC scores of 14 or higher. We also identified other risk factors, 79% of females and 86% of males were overweight or obese, and 39% had high blood pressure; consequently, we referred 427 patients to their PCP or a new medical home. Conclusions: The use of a community-based intervention using the FINDRISC type 2 diabetes risk assessment tool is a suitable, easy to perform intervention that can be applied in community settings by community lay health promoters.

Plug-and-play laser ablation-mass spectrometry for molecular imaging by means of dielectric barrier discharge ionization

The plug-and-play hyphenation of UV-laser ablation (LA) and mass spectrometry is presented, using dielectric barrier discharge ionization (DBDI). The DBDI source employed here is characterized by its unique geometry, being directly mounted onto the inlet capillary of a mass spectrometer. In the literature, this particular kind of DBDI source is also referred to as active capillary plasma ionization. It has been commercialized as soft ionization by chemical reaction in transfer (SICRIT) and will be addressed as DBDI in this study. LA-DBDI-MS was used for the direct, molecule-specific and spatially resolved analysis of various solid samples, such as coffee beans and pain killer tablets without extensive sample preparation. The combination of fast washout UV-laser ablation and the principle of the DBDI source used here allowed for highly efficient soft ionization as well as high spatial resolution down to 10 μm for molecular imaging.

Malondialdehyde in dried blood spots: a biomarker of systemic lipid peroxidation linked to cardiopulmonary symptoms and risk factors.

BackgroundThere are few oxidative biomarkers that can be used in resource-limited settings (e.g., rural Africa) where blood collection facilities are lacking. This study aims to evaluate the potential of malondialdehyde (MDA) in dried blood spots (DBS) as a useful biomarker to monitor cardiopulmonary health.MethodsWe first conducted a cross-validation comparison of matched capillary DBS, plasma, and whole venous blood collected from nine healthy volunteers for the measurement of total MDA (free + conjugated) and C-reactive protein (CRP), a well-established biomarker of systemic inflammation. Then a field study was conducted in a rural Senegal with a population of 441 women routinely exposed to severe household air pollution, examining associations of MDA and CRP levels in 882 DBS with self-reported cardiopulmonary symptoms.ResultsIn the cross-validation study, CRP levels were strongly correlated across DBS, plasma, and whole blood. MDA levels were correlated between DBS and whole blood and were 1–2 orders of magnitude lower in plasma, suggesting that DBS MDA may reflect total oxidation levels in intracellular and extracellular compartments. In the field study, we observed significantly higher MDA levels in women with secondhand smoke exposure. An interquartile range increase in MDA concentration was associated with 27.0% (95% CI: 3.1–56.5%) and 21.1% (95% CI: −3.5% to 52.0%) increases in the incidence of chest tightness and breath difficulty, respectively. In contrast, CRP levels were not associated with worse outcomes or risk factors.ConclusionsThese results support the use of DBS as a convenient alternative to venous blood when MDA is measured as a biomarker for cardiopulmonary health risk.

Detecting Trace Gases at PPM Levels with Low Temperature Plasma Optical Emission Spectroscopy

Detecting Trace Gases at PPM Levels with Low Temperature Plasma Optical Emission Spectroscopy

Expanding access to SARS-CoV-2 IgG and IgM serologic testing using fingerstick whole blood, plasma, and rapid lateral flow assays.

Serologic testing for SARS-CoV-2 antibodies can be used to confirm diagnosis, estimate seroprevalence, screen convalescent plasma donors, and assess vaccine efficacy. Dried blood spot (DBS) samples have been used for serology testing of various diseases in resource-limited settings. We examined the use of DBS samples and capillary blood (fingerstick) plasma collected in Microtainer tubes for SARS-CoV-2 testing with the automated Abbott ARCHITECT™ SARS-CoV-2 IgG and IgM assays and use of venous whole blood with a prototype PANBIO™ rapid point-of-care lateral flow SARS-CoV-2 IgG assay. The ARCHITECT™ SARS-CoV-2 IgG assay was initially optimized for use with DBS, venous and capillary plasma, and venous whole blood collected from patients with symptoms and PCR-confirmed COVID-19 and negative asymptomatic controls. Linearity and reproducibility was confirmed with 3 contrived DBS samples, along with sample stability and signal recovery after 14 days. ARCHITECT™ SARS-CoV-2 IgG and IgM assay results showed high concordance between fingerstick DBS and venous DBS samples, and between fingerstick DBS and venous whole blood samples (n = 61). Fingerstick plasma collected in Microtainer tubes (n = 109) showed 100% concordant results (R2=0.997) with matched patient venous plasma on the ARCHITECT™ SARS-CoV-2 IgG assay. High concordance of assay results (92.9% positive, 100% negative) was also observed for the PANBIO™ SARS-CoV-2 IgG assay compared to the ARCHITECT™ SARS-CoV-2 IgG assay run with matched venous plasma (n = 61). Fingerstick DBS and plasma samples are easy and inexpensive to collect and, along with the use of rapid point-of-care testing platforms, will expand access to SARS-CoV-2 serology testing, particularly in resource-limited areas.

Hollow electrode capillary plasma ionization source for rapid online detection of gaseous samples.

Gas chromatography mass spectrometry (GC-MS) with electron ionization (EI) is the most widely used analysis technique of gaseous samples, but it may be time-consuming for online monitoring of mixtures whose concentrations relatively change rapidly. On the contrary, current ionization methods, such as chemical ionization (CI) and proton transfer reaction (PTR), also have some disadvantages such as selectivity. Therefore, appropriate soft ionization sources are searched for rapid online detection. Hollow electrode capillary plasma ionization (HECPI) is based on single electrode plasma. A hollow capillary was placed as both the electrode and the inlet of the gaseous samples. The ionization source is coupled with a mass spectrometer for performance evaluation. Several typical compounds have been tested with HECPI-mass spectrometer. In this process, the dominant ion peaks of all compounds can be indexed as molecular ion peaks, and the product ions of HECPI are less than that of dielectric barrier discharge ionization (DBDI). Three gaseous samples (linalool, triethylamine, and styrene) with various concentrations have been used to further confirm the performance of this source, and the detection limit of linalool is as low as 10 ppb. HECPI is simple in structure and shows good performance. The results also show that HECPI has the potential to be an effective tool for detecting online gaseous samples rapidly.

Generation of high-quality GeV-class electron beams utilizing attosecond ionization injection

Acceleration of electrons in laser-driven plasma wakefields has been extended up to the 10 GeV energy within a distance of 10s of centimeters. However, in applications, requiring small energy spread within the electron bunch, only a small portion of the bunch can be used and often the low-energy electrons represent undesired background in the spectrum. We present a compact and tunable scheme providing clean and mono-energetic electron bunches with less than one percent energy spread and with central energy on the GeV level. It is a two-step process consisting of ionization injection with attosecond pulses and acceleration in a capillary plasma wave-guide. Semi-analytical theory and particle-in-cell simulations are used to accurately model the injection and acceleration steps.

Determination of finerenone – a novel, selective, nonsteroidal mineralocorticoid receptor antagonist – in human plasma by high-performance liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study in venous and capillary human plasma

A straightforward and rapid high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) assay allowing the sensitive and selective quantitation of finerenone (BAY 94–8862) in lithium heparin human plasma is described. Finerenone is a novel, selective, nonsteroidal mineralocorticoid receptor antagonist that is in phase III clinical trials for the treatment of chronic kidney disease. Finerenone quantitation is performed after addition of its stable isotope-labelled internal standard (ISTD) by protein precipitation with acidified acetonitrile followed by HPLC–MS/MS separation and detection. The determination of finerenone concentrations was validated for a plasma volume of 0.100 mL and subsequently also for a lower plasma volume of 0.010 mL, collected e.g. in paediatric studies. The analytical range was from 0.100 µg/L (lower limit of quantification) to 200 µg/L (upper limit of quantification). Inter-day accuracy was 99.7–105.0% for the plasma volume of 0.100 mL and 101.1–104.5% for the plasma volume of 0.010 mL. Inter-day precision was ≤ 7.0%, independent of the extracted plasma volume. A moderate, concentration-independent matrix effect on ionisation was observed for both finerenone and its ISTD of 0.535–0.617, which is fully compensated by the ISTD (ISTD-normalised matrix factors were 0.98–1.03). The assay was successfully applied with both validated plasma volumes to a clinical phase I study in which the pharmacokinetics of 20 mg finerenone were compared in capillary plasma (0.010 mL) and venous plasma (0.100 mL) in a concentration range from the lower limit of quantification to 310 µg/L (capillary plasma) and 252 µg/L (venous plasma). The area under the plasma concentration versus time curve was similar in both matrices, while maximum concentrations were 37% higher in capillary plasma. In conclusion, capillary sampling should not bias pharmacokinetic exposure estimates compared with venous plasma values, if limited to sampling times in the distribution and elimination phases of finerenone.

Malondialdehyde in Dried Blood Spots: A Biomarker of Systemic Lipid Peroxidation Linked to Cardiopulmonary Effects

Background: Few systemic oxidative biomarkers have been validated for use in resource-limited settings (e.g., rural Africa), where blood collection facilities are lacking. This study aims to evaluate the potential of malondialdehyde (MDA) in dried blood spots (DBS) as a convenient biomarker of cardiopulmonary effects. Methods: We conducted a cross-validation comparison of matched capillary DBS, plasma, and whole venous blood collected from nine healthy volunteers for the measurement of total MDA (free + conjugated) and C-reactive protein (CRP), a well-established biomarker of systemic inflammation. A field study was then conducted in a population of 441 rural Senegalese women facing routine exposure to severe household air pollution, to examine longitudinal associations of MDA and CRP levels with cardiopulmonary health outcomes and risk factors. Findings: In the cross-validation study, CRP levels were strongly correlated across DBS, plasma, and whole blood samples. MDA levels were similarly correlated across DBS and whole blood, and were 1~2 orders of magnitude lower in plasma, suggesting that DBS MDA may reflect total oxidation levels in intracellular and extracellular compartments. In the field study, we observed significantly higher MDA levels in women with a history of cardiovascular disease or secondhand smoke exposure. An interquartile range increase in MDA concentration was associated with 0·99% (95% CI: 0·02 – 1·96%) and 22% (95% CI: -2 – 51%) increases in systolic blood pressure and self-reported incidence of chest tightness, respectively. CRP levels were not similarly associated with these outcomes or risk factors. Interpretation: Results support the use of convenient DBS measures of MDA as a biomarker for cardiopulmonary health risk. Funding: International Initiative for Impact Evaluation, German Corporation for International Cooperation GmbH, German Federal Ministry of Education and Research, and Duke University’s Energy Initiative. Declaration of Interest: None to declare. Ethical Approval: This study consisted of cross-validation and field-vacomponents, both of which were approved by the institutional review board of Duke University.

Rapid analysis of fragrance allergens by dielectric barrier discharge ionization mass spectrometry.

Fragrances are organic compounds with pleasant odors that are widely used in every aspect of our daily life; some fragrance ingredients can cause allergic reactions. Hence, the qualitative and quantitative analysis of fragrance allergens can prevent consumers coming into contact with these compounds. In this study, we evaluated the ability of a dielectric barrier discharge ionization (DBDI) source for analyzing allergens that occur in fragrances. A home-built liquid-infusion device was used to evaporate the liquid samples. An active capillary plasma ionization source, which is based on a dielectric barrier discharge, was used to ionize the analytes. Mass spectra were acquired in positive ion mode with an LTQ Orbitrap mass spectrometer. Seven typical fragrance allergens were analyzed in this study. The limits of detections (LODs) were as low as 0.0001 ppm and a linear dynamic range of 2-3 orders of magnitude was achieved. Allergens in five different perfume products were successfully analyzed and quantified by this method, with analysis times of less than 1 min per sample. This work introduces a DBDI-MS-based analytical method for detecting and quantifying fragrance allergens. Since DBDI has the advantages of high sensitivity, simple operation and fast analysis time, it is very suitable for the rapid analysis of trace allergens in fragrances, and could easily be used for quality control of consumer products in the cosmetics market.

Radial density profile and stability of capillary discharge plasma waveguides of lengths up to 40 cm

Abstract We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650 $\mathrm{\mu} \mathrm{m}$ to 2 mm and lengths of 9 to 40 cm. To the best of the authors’ knowledge, 40 cm is the longest discharge capillary plasma waveguide to date. This length is important for $\ge$ 10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration stage. Evaluation of waveguide parameter variations showed that their focusing strength was stable and reproducible to $<0.2$ % and their average on-axis plasma electron density to $<1$ %. These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to date. Measurements of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation results. We show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the channel. However, they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.

Scaling of pulsed nanosecond capillary plasmas at different specific energy deposition

Nano-second, capillary discharges (nCDs) are unique plasma sources in their ability to sustain high specific energy deposition ω dep approaching 10 eV/molecule in molecular gases. This high energy loading on short timescales produces both high plasma densities and high densities of molecular exited states. These high densities of electrons and excited states interact with each other during the early afterglow through electron collision quenching and associative ionization. In this paper we discuss results from a two-dimensional computational investigation of a nCD sustained in air at a pressure of 28.5 mbar and with a voltage amplitude 20 kV. Discharges were investigated for two circuit configurations—a floating low voltage electrode and with the low voltage electrode connected to ground through a ballast resistor. The first configuration produced a single ionization wave from the high to low voltage electrode. The second produced converging ionization waves beginning at both electrodes. With a decrease of the tube radius, the velocity of the ionization fronts decreased while the shape of the ionization wave changed from the electron density being distributed smoothly in the radial direction, to being hollow shaped where there is a higher electron density near the tube wall. For sufficiently small tubes, the near-wall maxima merge to have the higher density on the axis of the capillary tube. In the early afterglow, the temporal and radial behavior of the N2(C3Πu) density is a sensitive function of ω dep due to electron collision quenching. These trends indicate that starting from ω dep ⩾ 0.3 eV/molecule, it is necessary to take into account interactions of electrons with electronically excited species during the discharge and early afterglow.

An integrated electrochemical microsystem for real-time treatment monitoring of clozapine in microliter volume samples from schizophrenia patients

This work presents the development of an electrochemical microsystem for antipsychotic clozapine treatment monitoring in schizophrenia patients. In our previous work, we demonstrated clozapine detection directly in spiked whole blood samples of a healthy volunteer using a chitosan–carbon nanotube-modified microelectrode with external counter and reference electrodes. Here we present the miniaturization of our previous clozapine sensing approach and its clinical validation in real samples obtained from 10 schizophrenia patients. We observed a sensitivity of 0.02 ± 2.3 × 10-4 mA/cm2µM and 0.003 ± 2.6 × 10-4 mA/cm2µM and a limit of detection of 0.08 ± 9.2 × 10-4 µM and 0.45 ± 0.04 µM using chitosan–carbon nanotube-modified microelectrodes in a 20 µL volume of spiked capillary plasma and capillary whole blood. Following a calibration curve, which was obtained from spiked samples of patients prior to clozapine therapy administration, clozapine capillary plasma and whole blood levels were recovered from patients’ samples after treatment with clozapine. The developed electrochemical microsystem allows clozapine analysis in a microliter volume of finger-pricked whole blood samples of schizophrenia patients without using any pretreatment steps. By further miniaturization and integration of this sensor into a point-of-care testing device, schizophrenia treatment management can be improved.