Solution blowing (SB) is a promising and scalable approach for the production of nanofibers. Air pressure, solution flowrate, and nozzle-collector distance were determined as effective process parameters, while solution concentration was also reported as a material parameter. Here we performed a parametric study on thermoplastic polyurethane/dimethyl formamide (TPU/DMF) solutions to examine the effect of such parameters on the resultant properties such as fiber diameter, diameter distribution, porosity, and air permeability of the nanofibrous webs. The obtained solution blown thermoplastic polyurethane (TPU) nanofibers had average diameter down to 170 6 112 nm, which is similar to that observed in electrospinning. However, the production rate per nozzle can be 20 times larger, which is primarily dependent on air pressure and solution flow rate (20 mL/h). Moreover, it was even possible to produce nanofibers polymer concentrations of 20%; however, this increased the average nanofiber diameter. The fibers produced from the TPU/DMF solutions at concentrations of 20% and 10% had average diameters of 671 6 136 nm and 170 6 112 nm, respectively. SB can potentially be used for the industrial-scale production of products such as nanofibrous filters, protective textiles, scaffolds, wound dressings, and battery components.

Extremely elastic and sensitive strain gauge sensors are highly demanded to keep track of strains in flexible electronics, skin deformation, and human movement. This report discusses a new approach to fabricate a stretchable, electrically conductive and sensitive strain gauge sensor which uses a polymeric nanofibrous composite of thermoplastic polyurethane (TPU) elastomer and conductive poly (3,4-ethylene dioxythiophene) poly(styrene sulfonate) (PEDOT: PSS) polymer as its basis. The nanofibrous composite was prepared using wet electrospinning technique. The designed TPU/PEDOT: PSS membrane loaded on a silicon rubber (SR) substrate holds an electrical resistance of 3 KΩ and a stable gauge factor of 20 up to 40% strains at room temperature. A single Wheatstone bridge was implemented to calibrate a micro-patterned strain sensor grid for voltage output versus an applied bending moment/force. The obtained results inferred that the fabricated sensor could be used to sense rapid and minute deformation actions in a wide range of engineering applications.

OBJECTIVES To evaluate the relationship between platelet reactivity and atherosclerotic burden in patients undergoing percutaneous coronary intervention (PCI) with pre-intervention volumetric intravascular ultrasound (IVUS) imaging. BACKGROUND Atherosclerosis progresses by the pathologic sequence of sub-clinical plaque rupture, thrombosis and healing. In this setting, increased platelet reactivity may lead to more extensive arterial thrombosis at the time of plaque rupture, leading to a more rapid progression of the disease. Alternatively, abnormal vessel wall biology with advanced atherosclerosis is known to enhance platelet reactivity. Therefore, it is possible that by either mechanism, increased platelet reactivity may be associated with greater atherosclerotic burden. METHODS We analyzed patients who underwent PCI with pre-intervention IVUS imaging and platelet reactivity functional assay (P2Y12 reaction-units [PRU]) performed >16 hours post-PCI after stabilization of clopidogrel therapy (administered pre-PCI). A PRU value of >230 defined high on-treatment platelet reactivity (HPR). RESULTS Among 335 patients (mean age 65.0; 71% male), there were 109 patients with HPR (32.5%) and 226 without HPR (67.5%), with HPR being associated with diabetes and chronic renal insufficiency. By IVUS analysis, HPR patients had significantly greater target lesion calcium length, calcium arc, and calcium index. Furthermore, HPR patients tended to have longer lesions and greater volumetric dimensions, indicating higher plaque volume, larger total vessel volume and also greater lumen volume, despite similar plaque burden. By multivariable analysis controlling for baseline clinical variables, HPR was the single consistent predictor of all IVUS parameters examined, including plaque volume, calcium length and calcium arc. CONCLUSIONS Increased platelet reactivity on clopidogrel treatment, as defined by a PRU value of >230, is associated with greater coronary artery atherosclerotic disease burden and plaque calcification.

In patients with NSTE-ACS and MV disease, MV PCI does not appear to provide a clear clinical benefit over SV PCI. Randomised clinical trials specifically addressing these two strategies in this population, with attention to quality of life and symptom relief, are warranted.

Polyvinylidene Fluoride (PVDF) piezoelectric electrospun nanofibers have been intensively used for sensing and actuation applications in the last decade. However, in most cases, random PVDF piezoelectric nanofiber mats have moderate piezoelectric response compared to aligned PVDF nanofibers. In this work, we demonstrate the effect of alignment conducted by a collector setup composed of two-metal bars with gab inside where the aligned fiber can be formed. That is what we called static aligned nanofibers, which is distinct from the dynamic traditional technique using a high speed rotating drum. The two-bar system shows a superior alignment degree for the PVDF nanofibers. Also, the effect of added carbon nanotubes (CNTs) of different concentrations to PVDF nanofibers is studied to observe the enhancement of piezoelectric response of PVDF nanofibers. Improvement of β-phase content of aligned (PVDF) nanofibers, as compared to randomly orientated fibers, is achieved. Significant change in the piezoelectricity of PVDF fiber is produced with added CNTs with saturation response in the case of 0.3 wt % doping of CNTs, and piezoelectric sensitivity of 73.8 mV/g with applied masses down to 100 g.

In this research work, nanofibrous hybrids are manufactured, characterized, and assessed as active antiviral and antibacterial membranes. In more detail, both polyvinyl alcohol (PVA) and thermoplastic polyurethane (TPU) nanofibrous (NF) membranes and their composites with embedded silver nanoparticles (Ag NPs) are manufactured by an electrospinning process. Their morphological structures have been investigated by a scanning electron microscope (SEM) which revealed a homogenous distribution and almost beads-free fibers in all manufactured samples. Characterization with spectroscopic tools has been performed and proved the successful manufacturing of Ag-incorporated PVA and TPU hybrid nanofibers. The crystalline phase of the nanofibers has been determined using an X-ray diffractometer (XRD) whose patterns showed their crystalline nature at an angle value (2θ) of less than 20°. Subsequent screening of both antiviral and antibacterial potential activities of developed nanohybrid membranes has been explored against different viruses, including SARS-Cov-2 and some bacterial strains. As a novel approach, the current work highlights potential effects of several polymeric hybrids on antiviral and antibacterial activities particularly against SARS-Cov-2. Moreover, two types of polymers have been tested and compared; PVA of excellent biodegradable and hydrophilic properties, and TPU of excellent mechanical, super elasticity, hydrophobicity, and durability properties. Such extreme polymers can serve a wide range of applications such as PPE, filtration, wound healing, etc. Consequently, assessment of their antiviral/antibacterial activities, as host matrices for Ag NPs, is needed for different medical applications. Our results showed that TPU-Ag was more effective than PVA-Ag as HIV-1 antiviral nanohybrid as well as in deactivating spike proteins of SARS-Cov-2. Both TPU-Ag and PVA-Ag nanofibrous membranes were found to have superior antimicrobial performance by increasing Ag concentration from 2 to 4 wt.%. Additionally, the developed membranes showed acceptable physical and mechanical properties along with both antiviral and antibacterial activities, which can enable them to be used as a promising functional layer in Personal Protective Equipment (PPE) such as (surgical gowns, gloves, overshoes, hair caps, etc.). Therefore, the developed functional membranes can support the decrease of both coronavirus spread and bacterial contamination, particularly among healthcare professionals within their workplace settings.

Improving properties of polymeric and non-polymeric fibers, for example mechanical, dimensional stability, thermal degradation, and etc. with understanding a recent theoretical investigation on the solid mechanism of single crystal growth leads to obtain fiber-based products with unusual characteristics. Similarly, high performance fibers are important engineering products and widely used due to their outstanding mechanical property along with dimensional stability. They have found extensive use as fiber reinforcement and can be utilized in many applications such as cords, ropes, performance fabrics, electronic packaging, sports equipment and fiber optics (Hearle, 2001;Kerr, Chawla and Chawla, 2005). It is well known that the highest tenacity and elastic moduli reported for such fibers are still much lower than their theoretical values. An extensive open gap between theoretical values and practical results encourage scientists to work and improve the mechanical properties. On the other hand, due to their nonconventional chemistry and instrumentation, many researches have been concentrated on reducing its production costs. Additionally, there is no single fiber chemistry that can withstand all sort of end-use conditions. The objective of this review paper is to provide a critical and constructive analysis on current state of art high performance fiber production and modification techniques. Current problems and novel solutions were emphasized separately.

Interest in piezoelectric nanocomposites has been vastly growing in the energy harvesting field. They are applied in wearable electronics, mechanical actuators, and electromechanical membranes. In this research work, nanocomposite membranes of different blend ratios from PVDF and TPU have been synthesized. The PVDF is responsible for piezoelectric performance where it is one of the promising polymeric organic materials containing β-sheets, to convert applied mechanical stress into electric voltage. In addition, the TPU is widely used in the plastic industry due to its superior elasticity. Our work investigates the piezoresponse analysis for different blending ratios of PVDF/TPU. It has been found that TPU blending ratios of 15–17.5% give higher output voltage at different stresses conditions along with higher piezosensitivity. Then, TPU addition with its superior mechanical elasticity can partially compensate PVDF to enhance the piezoelectric response of the PVDF/TPU nanocomposite mats. This work can help reducing the amount of added PVDF in piezoelectric membranes with enhanced piezo sensitivity and mechanical elasticity.