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Carbon felt is widely used due to its lightweight and conductive nature. However, limited research has been conducted regarding the tension applied during its preparation. This study aims to explore the influence of different loading tensions during the carbonization process on the properties of acrylic-based carbon felts. Enhanced flexibility, lower shrinkage and improved mechanical and electrical properties were found for the samples obtained in the edge loading mode. Subsequently, the performance of carbon felts in electromagnetic interference (EMI) shielding and resistive heating was studied. The carbon felts achieved a notable EMI shielding effectiveness of 55 dB. The specific shielding effectiveness values are significantly higher than other reported materials due to their low density and high porosity. Moreover, the carbon felts displayed commendable electrical heating performance through high heating rates and superior heating efficiency. Lastly, the structural stability was assessed via self-designed bending experiments. Good stability of the resistance and heating behavior of the carbon felts across multiple bending cycles was observed. With low manufacturing costs, good stability and air permeability, the flexible carbon felt is expected to be widely used for barrier applications and wearable electronics.

This paper presents a method for direct and alternating current electrospinning of polymeric solutions of three less common polyamides (nylons). Homopolyamide PA 8, heteropolyamide PA 6|9 and semi-aromatic amide (phthalamide) PA 6(3)T were dissolved in the formic acid and dichloromethane mixture, which have proved to be a suitable solvent for various other linear polyamides. The dependence of the viscosity, electrical conductivity, and spinnability via the direct (DC) and alternating current (AC) technology on the solution concentration was observed. Scanning electron microscope images of the prepared nanofibers were acquired and consequently analyzed for fiber defects, followed by measuring the fiber diameters. The differences in the nanofiber quality of DC layers and AC plumes were discussed. Finally, the optimal concentrations for the electrospinning of the examined solutions were determined. The communication follows our previous work and extends the number of electrospinnable polyamides, thus facilitating future research in this area.

Infectious diseases, which often result in deadly sepsis or septic shock, represent a major global health problem. For understanding the pathophysiology of sepsis and developing new treatment strategies, reliable and clinically relevant animal models of the disease are necessary. In this review, two large animal (porcine) models of sepsis induced by either peritonitis or bacteremia are introduced and their strong and weak points are discussed in the context of clinical relevance and other animal models of sepsis, with a special focus on cardiovascular and immune systems, experimental design, and monitoring. Especially for testing new therapeutic strategies, the large animal (porcine) models represent a more clinically relevant alternative to small animal models, and the findings obtained in small animal (transgenic) models should be verified in these clinically relevant large animal models before translation to the clinical level.

Structural parameters are critical for the final properties of fibrous materials. Three common parameters (i.e., porosity, thickness and average fiber diameter) of each fibrous material are simultaneously determined based on their air penetration behavior. The Ergun-type equation and the Kozeny-type equation, with the help of the optimization method, are applied to conduct the inverse characterization. The prediction performance of the equations is evaluated by comparing the given pressure drop and the values predicted by the Ergun-type and Kozeny-type equations. The inversely determined parameters are compared with the directly measured values. The results show that the Ergun-type equation and the Kozeny-type equation are suitable for various fibrous materials, including conventional nonwoven materials and nanofibrous membranes. The selection criteria of these two equations are provided based on the relation of pressure drop-airflow velocity and the prediction accuracy. The results also suggest that the Ergun-type equation's coefficients and the Blake–Kozeny–Carman constant of the Kozeny-type equation need to be determined for each material. The relative errors for most of the inversely determined parameters are reasonable. The findings indicate that the airflow-based method is feasible for fibrous materials.

Polymeric nano- and microfibers were tested as potential sorbents for the extraction of five neonicotinoids from natural waters. Nanofibrous mats were prepared from polycaprolactone, polyvinylidene fluoride, polystyrene, polyamide 6, polyacrylonitrile, and polyimide, as well as microfibers of polyethylene, a polycaprolactone nano- and microfiber conjugate, and polycaprolactone microfibers combined with polyvinylidene fluoride nanofibers. Polyimide nanofibers were selected as the most suitable sorbent for these analytes and the matrix. A Lab-In-Syringe system enabled automated preconcentration via online SPE of large sample volumes at low pressure with analyte separation by HPLC. Several mat layers were housed in a solvent filter holder integrated into the injection loop of an HPLC system. After loading 2 mL sample on the sorbent, the mobile phase eluted the retained analytes onto the chromatographic column. Extraction efficiencies of 68.8–83.4% were achieved. Large preconcentration factors ranging from 70 to 82 allowed reaching LOD and LOQ values of 0.4 to 1.7 and 1.2 to 5.5 µg·L−1, respectively. Analyte recoveries from spiked river waters ranged from 53.8% to 113.3% at the 5 µg·L−1 level and from 62.8% to 119.8% at the 20 µg·L−1 level. The developed methodology proved suitable for the determination of thiamethoxam, clothianidin, imidacloprid, and thiacloprid, whereas matrix peak overlapping inhibited quantification of acetamiprid.

The paper provides a description of the potential for the direct current- and alternating current-driven electrospinning of various linear aliphatic polyamides (PA). Sets with increasing concentrations of selected PAs were dissolved in a mixture of formic acid and dichloromethane at a weight ratio of 1:1 and spun using a bar electrode applying direct and alternating high voltage. The solubility and spinnability of the polyamides were investigated and scanning electron microscopy (SEM) images were acquired of the resulting nanofiber layers. The various defects of the spun fibers and their diameters were detected and subsequently measured. Moreover, the dynamic viscosity and conductivity were also subjected to detailed investigation. The most suitable concentrations for each of the PAs were determined according to previous findings, and the solutions were spun using a NanospiderTM device at the larger scale. The fiber diameters of these samples were also measured. Finally, the surface energy of the fiber layers produced by the NanospiderTM device was measured aimed at selecting a suitable PA for a particular application.

Application of the poly-ɛ-caprolactone composite sorbent consisting of the micro- and nanometer fibers for the on-line extraction of non-steroidal anti-inflammatory drugs from a biological matrix has been introduced. A 100 μL human serum sample spiked with ketoprofen, naproxen, sodium diclofenac, and indomethacin was directly injected in the extraction cartridge filled with the poly-ɛ-caprolactone composite sorbent. This cartridge was coupled with a chromatographic instrument via a six-port switching valve allowing the analyte extraction and separation within a single analytical run. The 1.5 min long extraction step isolated the analytes from the proteinaceous matrix was followed by their 13 min HPLC separation using Ascentis Express RP-Amide (100 × 4.6 mm, 5 µm) column. The recovery of all analytes from human serum tested at three concentration levels ranged from 70.1% to 118.7%. The matrix calibrations were carried out in the range 50 to 20,000 ng mL−1 with correlation coefficients exceeding 0.996. The detection limit was 15 ng mL−1, and the limit of quantification corresponded to 50 ng mL−1. The developed method was validated and successfully applied for the sodium diclofenac determination in real patient serum. Our study confirmed the ability of the poly-ɛ-caprolactone composite sorbent to remove the proteins from the biological matrix, thus serving as an alternative to the application of restricted-access media.

Hydrogels are suitable for osteochondral defect regeneration as they mimic the viscoelastic environment of cartilage. However, their biomechanical properties are not sufficient to withstand high mechanical forces. Therefore, we have prepared electrospun poly-ε-caprolactone-chitosan (PCL-chit) and poly(ethylene oxide)-chitosan (PEO-chit) nanofibers, and FTIR analysis confirmed successful blending of chitosan with other polymers. The biocompatibility of PCL-chit and PEO-chit scaffolds was tested; fibrochondrocytes and chondrocytes seeded on PCL-chit showed superior metabolic activity. The PCL-chit nanofibers were cryogenically grinded into microparticles (mean size of about 500 µm) and further modified by polyethylene glycol–biotin in order to bind the anti-CD44 antibody, a glycoprotein interacting with hyaluronic acid (PCL-chit-PEGb-antiCD44). The PCL-chit or PCL-chit-PEGb-antiCD44 microparticles were mixed with a composite gel (collagen/fibrin/platelet rich plasma) to improve its biomechanical properties. The storage modulus was higher in the composite gel with microparticles compared to fibrin. The Eloss of the composite gel and fibrin was higher than that of the composite gel with microparticles. The composite gel either with or without microparticles was further tested in vivo in a model of osteochondral defects in rabbits. PCL-chit-PEGb-antiCD44 significantly enhanced osteogenic regeneration, mainly by desmogenous ossification, but decreased chondrogenic differentiation in the defects. PCL-chit-PEGb showed a more homogeneous distribution of hyaline cartilage and enhanced hyaline cartilage differentiation.

A sixty six-year old man with a history of arterial hypertension and excellent quality of life was successfully treated for community-acquired pneumonia with an empirical antibiotic in the outpatient setting. However he developed painless jaundice, progressive dyspnoea and intermittent chest pain about two weeks later. He sought his GP who immediately referred him to the regional hospital. Next, he was transferred to the Teaching Hospital in Pilsen due to a worsening condition shortly after the ambulatory examination. The case report describes and discusses the complicated course and management of a rare disease. [ABSTRACT FROM AUTHOR]

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