How Plasmon Ag Nanoparticles can Enhance the Power Performance of a Thermoelectric Generator.

The development of wearable thermoelectric generators (wTEG) represents a promising strategy to replace batteries and supercapacitors required to supply electrical energy for portable electronic devices. However, the main drawback of wTEGs is that the thermal gradient between the skin and the ambient is minimal, reducing the power output produced by the generator. Therefore, it is necessary to improve the thermal management of wTEG in order to increase its efficiency. This work deals with the preparation of a thermoelectric generator that harnesses the plasmonic heating effect to enhance the thermal gradient of the final device. The thermoelectric layer is created through the in situ polymerization of terthiophene (3T) within a polyurethane matrix, utilizing silver (Ag) (I) and copper (II) perchlorate as oxidants. The plasmonic film, composed of Ag-NP (nanoparticles), is formed via photocatalytic reduction of silver nitrate in the presence of titanium oxide. These layers are then meticulously assembled to yield the hybrid plasmonic/thermoelectric generator.

Lung allograft transbronchial cryobiopsy for critical ventilated patients: a randomised trial.

BACKGROUND: Transbronchial lung cryobiopsy is an emerging technique for diagnosing pulmonary rejection. However, no prospective studies of this procedure for critically ill lung transplant recipients who require mechanical ventilation in the intensive care unit (ICU) have been performed. METHODS: From March 2017 to January 2020, we performed a prospective, randomised, comparative study to assess the diagnostic yield, histological quality and safety of transbronchial lung biopsy using biopsy forceps, a 1.9-mm cryoprobe or a 2.4-mm cryoprobe. RESULTS: 89 out of 129 consecutive transbronchial biopsy procedures (forceps group, 28 procedures; 1.9-mm cryoprobe group, 31 procedures; 2.4-mm cryoprobe group, 30 procedures) were randomised. Compared with lung samples from the forceps and 1.9-mm cryoprobe groups, lung samples from the 2.4-mm cryoprobe group allowed the most definitive diagnoses (p<0.01 and p=0.02, respectively), the most diagnoses of acute lung rejection (p<0.01 and p=0.01, respectively) and the most diagnoses of rejection severity (p<0.01 and p<0.01, respectively). These samples were larger (p<0.01 and p=0.04, respectively), had the most adequate alveolar tissue (p<0.01 and p=0.02, respectively), had more vessels per procedure (p<0.01 and p=0.01, respectively) and had no significant crush artefacts. Moderate bleeding was observed in 23% of cases (p=0.01 and p=0.08, respectively). No severe bleeding was observed. CONCLUSIONS: Transbronchial lung biopsy using a 2.4-mm cryoprobe allows the safe collection of lung tissue samples from critically ill lung transplant recipients who require mechanical ventilation in the ICU and has good diagnostic performance.

Facile Tailoring of Structures for Controlled Release of Paracetamol from Sustainable Lignin Derived Platforms.

Nowadays, sustainable materials are receiving significant attention due to the fact that they will be crucial for the development of the next generation of products and devices. In the present work, hydrogels have been successfully synthesized using lignin which is non-valorized biopolymer from the paper industry. Hydrogels were prepared via crosslinking with Poly(ethylene) glycol diglycidyl ether (PEGDGE). Different crosslinker ratios were used to determine their influence on the structural and chemical properties of the resulting hydrogels. It has been found that pore size was reduced by increasing crosslinker amount. The greater crosslinking density increased the swelling capacity of the hydrogels due to the presence of more hydrophilic groups in the hydrogel network. Paracetamol release test showed higher drug diffusion for hydrogels produced with a ratio lignin:PEGDGE 1:1. The obtained results demonstrate that the proposed approach is a promising route to utilize lignocellulose waste for producing porous materials for advanced biomedical applications in the pharmacy industry.

BALF cytokines in different phenotypes of chronic lung allograft dysfunction in lung transplant patients.

The long-term success of lung transplantation (LT) is limited by chronic lung allograft dysfunction (CLAD). Different phenotypes of CLAD have been described, such as bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). The purpose of this study was to investigate the levels of cytokines and chemokines in bronchoalveolar lavage fluid (BALF) as markers of these CLAD phenotypes. BALF was collected from 51 recipients who underwent (bilateral and unilateral) LT. The study population was divided into three groups: stable (ST), BOS, and RAS. Levels of interleukin (IL)-4, IL-5, IL-6, IL-10, IL-13, tumor necrosis factor alpha (TNF-α), interferon-gamma (IFN-γ), and granulocyte-macrophage colony-stimulating factor (GM-CSF) were measured using the multiplex technology. BALF neutrophilia medians were higher in BOS (38%) and RAS (30%) than in ST (8%) (P=.008; P=.012). Regarding BALF cytokines, BOS and RAS patients showed higher levels of INF-γ than ST (P=.02; P=.008). Only IL-5 presented significant differences between BOS and RAS (P=.001). BALF neutrophilia is as a marker for both CLAD phenotypes, BOS and RAS, and IL-5 seems to be a potential biomarker for the RAS phenotype.

Controlling the thermoelectric properties of polymers: application to PEDOT and polypyrrole.

Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) films have been prepared by an electrochemical method in a three electrode cell. The films have been obtained at different oxidation levels regarded as bipolaron, polaron and neutral states by varying the voltage, as is usually done in conjugated heterocyclic polymers. The voltage (-0.2 < V < 1.0 V) has been applied versus a Ag/AgCl reference electrode, producing a variation of one order of magnitude in the electrical conductivity and the Seebeck coefficient of the films. In the voltage range explored, the electrical conductivity increases from 80 to 766 S cm(-1) in PEDOT and from 15 to 160 S cm(-1) in PPy, while the Seebeck coefficient decreases from 37.0 to 9.6 µV K(-1) for PEDOT and from 51.0 to 6.7 µV K(-1) for PPy. The thermal conductivity remains unchanged with the oxidation state of the film, κ ≈ 0.35 ± 0.02 W m(-1) K(-1) for PEDOT and 0.17 ± 0.02 W m(-1) K(-1) for PPy. A maximum thermoelectric efficiency of 1.4 × 10(-2) for PEDOT and 6.8 × 10(-3) for PPy has been achieved. These changes are related to the doping level of the polymer films and they can be accurately controlled by the applied voltage. In this work, we provide a very simple method to control and optimize the power factor or the figure of merit of conducting polymers.

On the design of lignin reinforced acrylic acid/hyaluronic acid adhesive hydrogels with conductive PEDOT:HA nanoparticles.

Hydrogels are of great importance in biomedical engineering. They possess the ability to mimic bodily soft tissues, and this allows exciting possibilities for applications such as tissue engineering, drug delivery and wound healing, however much work remains on stability and mechanical robustness to allow for translation to clinical applications. The work herein describes the synthesis and analysis of a biocompatible, versatile hydrogel that has tailorable swelling, high stability when swollen and thermal stability. The synthesis methods used produce a hydrogel with high elasticity, good mechanical properties and rapid crosslinking whilst displaying biocompatibility, adhesion, and conductivity. It has been shown that cell viability in the samples is above 80 % in all cases, a Young's Modulus of up to 85 kPa and high swelling degrees were achieved. These materials show potential for use in numerous applications such as adhesive sensors, skin grafts and drug delivery systems.

Synthesis of Sustainable Lignin Precursors for Hierarchical Porous Carbons and Their Efficient Performance in Energy Storage Applications.

Lignin-derived porous carbons have great potential for energy storage applications. However, their traditional synthesis requires highly corrosive activating agents in order to produce porous structures. In this work, an environmentally friendly and unique method has been developed for preparing lignin-based 3D spherical porous carbons (LSPCs). Dropwise injection of a lignin solution containing PVA sacrificial templates into liquid nitrogen produces tiny spheres that are lyophilized and carbonized to produce LSPCs. Most of the synthesized samples possess excellent specific surface areas (426.6-790.5 m2/g) along with hierarchical micro- and mesoporous morphologies. When tested in supercapacitor applications, LSPC-28 demonstrates a superior specific capacitance of 102.3 F/g at 0.5 A/g, excellent rate capability with 70.3% capacitance retention at 20 A/g, and a commendable energy density of 2.1 Wh/kg at 250 W/kg. These materials (LSPC-46) also show promising performance as an anode material in sodium-ion batteries with high reversible capacity (110 mAh g-1 at 100 mA g-1), high Coulombic efficiency, and excellent cycling stability. This novel and green technique is anticipated to facilitate the scalability of lignin-based porous carbons and open a range of research opportunities for energy storage applications.

Synthesis of PEDOT/CNTs Thermoelectric Thin Films with a High Power Factor.

In this study, we have improved the power factor of conductive polymer nanocomposites by combining layer-by-layer assembly with electrochemical deposition to produce flexible thermoelectric materials based on PEDOT/carbon nanotubes (CNTs)-films. To produce films based on CNTs and PEDOT, a dual approach has been employed: (i) the layer-by-layer method has been utilized for constructing the CNTs layer and (ii) electrochemical polymerization has been used in the synthesis of the conducting polymer. Moreover, the thermoelectric properties were optimized by controlling the experimental conditions including the number of deposition cycles and electropolymerizing time. The electrical characterization of the samples was carried out by measuring the Seebeck voltage produced under a small temperature difference and by measuring the electrical conductivity using the four-point probe method. The resulting values of the Seebeck coefficient S and σ were used to determine the power factor. The structural and morphological analyses of CNTs/PEDOT samples were carried out using scanning electron microscopy (SEM) and Raman spectroscopy. The best power factor achieved was 131.1 (µWm-1K-2), a competitive value comparable to some inorganic thermoelectric materials. Since the synthesis of the CNT/PEDOT layers is rather simple and the ingredients used are relatively inexpensive and environmentally friendly, the proposed nanocomposites are a very interesting approach as an application for recycling heat waste.

Synthesis and evaluation of alginate, gelatin, and hyaluronic acid hybrid hydrogels for tissue engineering applications.

Tissue engineering (TE) has been proposed extensively as a potential solution to the worldwide shortages of donor organs needed for transplantation. Over the years, numerous hydrogel formulations have been studied for various TE endeavours, including bone, cardiac or neural TE treatment strategies. Amongst the materials used, organic and biocompatible materials which aim to mimic the natural extracellular matrix of the native tissue have been investigated to create biomimicry regenerative environments. As such, the comparison between studies using the same materials is often difficult to accomplish due to varying material concentrations, preparation strategies, and laboratory settings, and as such these variables have a huge impact on the physio-chemical properties of the hydrogel systems. The purpose of the current study is to investigate popular biomaterials such as alginate, hyaluronic acid and gelatin in a variety of concentrations and hydrogel formulations. This aims to provide a clear and comprehensive understanding of their behaviours and provide a rational approach as to the appropriate selection of natural polysaccharides in specific targeted TE strategies.

The impact of varying dextran oxidation levels on the inhibitory activity of a bacteriocin loaded injectable hydrogel.

In the design of injectable antimicrobial dextran-alginate hydrogels, the impact of dextran oxidation and its subsequent changes in molecular weight and the incorporation of glycol chitosan on (i) gel mechanical strength and (ii) the inhibitory profile of an encapsulated bacteriocin, nisin A, are explored. As the degree of oxidation increases, the weight average molecular mass of the dextran decreases, resulting in a reduction in elastic modulus of the gels made. Upon encapsulation of the bacteriocin nisin into the gels, varying the dextran mass/oxidation level allowed the antimicrobial activity against S. aureus to be controlled. Gels made with a higher molecular weight (less oxidised) dextran show a higher initial degree of inhibition while those made with a lower molecular weight (more oxidised) dextran exhibit a more sustained inhibition. Incorporating glycol chitosan into gels composed of dextran with higher masses significantly increased their storage modulus and the gels' initial degree of inhibition.

The Role of Diisocyanate Structure to Modify Properties of Segmented Polyurethanes.

Segmented thermoplastic polyurethanes (PU) were synthetized using a polycarbonatediol macrodiol as a flexible or soft segment with a molar mass of 2000 g/mol, and different diisocyanate molecules and 1,4-butanediol as a rigid or hard segment. The diisocyanate molecules employed are 3,3'-Dimethyl-4,4'-biphenyl diisocyanate (TODI), 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-Methylenebis(phenyl isocyanate) 1-isocyanato-4-[(4-phenylisocyanate)methyl]benzene and 1-isocyanate-4-[(2-phenylisocyanate) methyl]benzene (ratio 1:1) (MDIi), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (HDI). The polyurethanes obtained reveal a wide variation of microphase separation degree that is correlated with mechanical properties. Different techniques, such as DSC, DMA, and FTIR, have been used to determine flexible-rigid segment phase behavior. Mechanical properties, such as tensile properties, Shore D hardness, and "compression set", have been determined. This work reveals that the structure of the hard segment is crucial to determine the degree of phase miscibility which affects the resulting mechanical properties, such as tensile properties, hardness, and "compression set".

Coating of Felt Fibers with Carbon Nanotubes and PEDOT with Different Counterions: Temperature and Electrical Field Effects.

The use of wearable devices has promoted new ways of integrating these devices, one of which is through the development of smart textiles. Smart textiles must possess the mechanical and electrical properties necessary for their functionality. This study explores the impact of polymer-felt microstructure variations on their morphology, electrical, and mechanical properties. The application of thermal treatment, along with an electric field, leads to a substantial structural reorganization of the molecular chains within pristine felt. This results in a system of nanofibrils coated with MWCNT-PEDOT, characterized by highly ordered counterions that facilitate the flow of charge carriers. Both temperature and an electric field induce reversible microstructural changes in pristine felt and irreversible changes in coated felt samples. Furthermore, electropolymerization of PEDOT significantly enhances electrical conductivity, with PEDOT:BTFMSI-coated fabric exhibiting the highest conductivity.

Nanoencapsulation of Organic Phase Change Materials in Poly(3,4-Ethylenedioxythiophene) for Energy Storage and Conversion.

This work focuses on the encapsulation of two organic phase change materials (PCMs), hexadecane and octadecane, through the formation of nanocapsules of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) obtained by oxidative polymerization in miniemulsion. The energy storage capacity of nanoparticles is studied by preparing polymer films on supporting substrates. The results indicate that the prepared systems can store and later release thermal energy in the form of latent heat efficiently, which is of vital importance to increase the efficiency of future thermoelectric devices.

Laparoscopic Extravesical Reimplantation in Children with Primary Obstructive Megaureter.

Introduction: Conservative management of primary obstructive megaureter (POM) appears as the best option in patients with adequate ureteral drainage. Nevertheless, surgical intervention is indicated in cases of recurrent urinary tract Infections (UTIs), deterioration of split renal function, and significant obstruction. The gold standard includes: Ureteral reimplantation with or without tapering by open approach. Our objective is to report our results in the treatment of POM by Laparoscopic-Assisted Extracorporeal Ureteral Tapering Repair (EUTR) and Laparoscopic Ureteral Extravesical Reimplantation (LUER) and to evaluate the efficacy and security of this procedure. Materials and Methods: From January 2011 to January 2018 a retrospective study was carried out by reviewing the clinical records of 26 patients diagnosed with POM. All patients underwent laparoscopic ureteral reimplantation following Lich Gregoir technique. In cases of ureteral tapering, an EUTR was performed with Hendren technique. Results: In all patients LUER and EUTR were performed without conversion. No ureteral tapering was necessary in six patients. There were no intraoperative complications. At 3 months in postoperative, 1 patient presented a febrile UTI, and subsequently, a vesicoureteral reflux (VUR) grade III was diagnosed by voiding cystourethrogram. In this case, a redo laparoscopic surgery was performed. After long-term follow-up, all patients were asymptomatic without recurrence of POM or VUR. Conclusion: Laparoscopic-assisted EUTR and LUER following Lich Gregoir technique for POM constitutes a safe and effective option, with a success rate similar to that of open procedure. Nevertheless, larger randomized prospective trials and long-term follow-up are required to validate this technique.

Organic Thermoelectric Nanocomposites Assembled via Spraying Layer-by-Layer Method.

Thermoelectric (TE) materials have been considered as a promising energy harvesting technology for sustainably providing power to electronic devices. In particular, organic-based TE materials that consist of conducting polymers and carbon nanofillers make a large variety of applications. In this work, we develop organic TE nanocomposites via successive spraying of intrinsically conductive polymers such as polyaniline (PANi) and poly(3,4-ethylenedioxy- thiophene):poly(styrenesulfonate) (PEDOT:PSS) and carbon nanofillers, and single-walled carbon nanotubes (SWNT). It is found that the growth rate of the layer-by-layer (LbL) thin films, which comprise a PANi/SWNT-PEDOT:PSS repeating sequence, made by the spraying method is greater than that of the same ones assembled by traditional dip coating. The surface structure of multilayer thin films constructed by the spraying approach show excellent coverage of highly networked individual and bundled SWNT, which is similarly to what is observed when carbon nanotubes-based LbL assemblies are formed by classic dipping. The multilayer thin films via the spray-assisted LbL process exhibit significantly improved TE performances. A 20-bilayer PANi/SWNT-PEDOT:PSS thin film (~90 nm thick) yields an electrical conductivity of 14.3 S/cm and Seebeck coefficient of 76 µV/K. These two values translate to a power factor of 8.2 µW/m·K2, which is 9 times as large as the same films fabricated by a classic immersion process. We believe that this LbL spraying method will open up many opportunities in developing multifunctional thin films for large-scaled industrial use due to rapid processing and the ease with which it is applied.

Serial lung ultrasound in monitoring viral pneumonia: the lesson learned from COVID-19.

Background: Lung ultrasound (LUS) has proven to be useful in the evaluation of lung involvement in COVID-19. However, its effectiveness for predicting the risk of severe disease is still up for debate. The aim of the study was to establish the prognostic accuracy of serial LUS examinations in the prediction of clinical deterioration in hospitalised patients with COVID-19. Methods: Prospective single-centre cohort study of patients hospitalised for COVID-19. The study protocol consisted of a LUS examination within 24 h from admission and a follow-up examination on day 3 of hospitalisation. Lung involvement was evaluated by a 14-area LUS score. The primary end-point was the ability of LUS to predict clinical deterioration defined as need for intensive respiratory support with high-flow oxygen or invasive mechanical ventilation. Results: 200 patients were included and 35 (17.5%) of them reached the primary end-point and were transferred to the intensive care unit (ICU). The LUS score at admission had been significantly higher in the ICU group than in the non-ICU group (22 (interquartile range (IQR) 20-26) versus 12 (IQR 8-15)). A LUS score at admission ≥17 was shown to be the best cut-off point to discriminate patients at risk of deterioration (area under the curve (AUC) 0.95). The absence of progression in LUS score on day 3 significantly increased the prediction accuracy by ruling out deterioration with a negative predictive value of 99.29%. Conclusion: Serial LUS is a reliable tool in predicting the risk of respiratory deterioration in patients hospitalised due to COVID-19 pneumonia. LUS could be further implemented in the future for risk stratification of viral pneumonia.

Cocaine use during pregnancy assessed by hair analysis in a Canary Islands cohort.

BACKGROUND: Drug use during pregnancy is difficult to ascertain, and maternal reports are likely to be inaccurate. The aim of this study was to estimate the prevalence of illicit drug use among pregnant women by using maternal hair analysis. METHODS: A toxicological analysis of hair was used to detect chronic recreational drug use during pregnancy. In 2007, 347 mother-infant dyads were included from the Hospital La Candelaria, Santa Cruz de Tenerife, Canary Islands (Spain). Data on socioeconomic characteristics and on substance misuse during pregnancy were collected using a structured questionnaire. Drugs of abuse: opiates, cocaine, cannabinoids and amphetamines were detected in maternal hair by immunoassay followed by gas chromatography-mass spectrometry for confirmation and quantitation. RESULTS: Hair analysis revealed 2.6% positivity for cocaine and its metabolites. Use of cocaine during pregnancy was associated with unusual behaviour with potentially harmful effects on the baby. CONCLUSIONS: The results of the study demonstrate significant cocaine use by pregnant women in Canary Islands. The data should be used for the purpose of preventive health and policy strategies aimed to detect and possibly to avoid in the future prenatal exposure to drugs of abuse.

Cellulose: Characteristics and applications for rechargeable batteries.

Cellulose, an abundant natural polymer, has promising potential to be used for energy storage systems because of its excellent mechanical, structural, and physical characteristics. This review discusses the structural features of cellulose and describes its potential application as an electrode, separator, and binder, in various types of high-performing batteries. Various surface and structural characteristics of cellulose (e.g., fiber size, surface functional groups, the hierarchy of pores, and porosity levels) that contribute to its electrochemical performance are discussed. Cellulose structure/property/processing/function relationships are further focused and elucidated in terms of the latest developments in the emerging field of sustainable materials in Li-Ion, Na-Ion, and LiS batteries.

Sustainable lignin precursors for tailored porous carbon-based supercapacitor electrodes.

Sustainable materials are attracting a lot of attention since they will be critical in the creation of the next generation of products and devices. In this study, hydrogels were effectively synthesized utilizing lignin, a non-valorised biopolymer from the paper industry. This study proposes a method based on utilizing lignin to create highly swollen hydrogels using poly(ethylene) glycol diglycidyl ether (PEGDGE) as a crosslinking agent. The influence of different crosslinker ratios on the structural and chemical properties of the resultant hydrogels was investigated. Pore size was observed to be lowered when the amount of crosslinker was increased. The inclusion of additional hydrophilic groups in the hydrogel network decreased the swelling capacity of the hydrogels as the crosslinking density increases. These precursor materials were carbonised and electrochemically tested for application as electrodes for supercapacitors with capacitance characterized as a function of crosslinker ratio.

Curcumin encapsulated polylactic acid nanoparticles embedded in alginate/gelatin bioinks for in situ immunoregulation: Characterization and biological assessment.

Curcumin is a known naturally occurring anti-inflammatory agent derived from turmeric, and it is commonly used as a herbal food supplement. Here, in order to overcome the inherent hydrophobicity of curcumin (Cur), polylactic acid (PLA) nanoparticles (NPs) were synthesised using a solvent evaporation, and an oil-in-water emulsion method used to encapsulate curcumin. Polymeric NPs also offer the ability to control rate of drug release. The newly synthesised NPs were analysed using a scanning electron microscope (SEM), where results show the NPs range from 50 to 250 nm. NPs containing graded amounts of curcumin (0 %, 0.5 %, and 2 %) were added to cultures of NIH3T3 fibroblast cells for cytotoxicity evaluation using the Alamar Blue assay. Then, the curcumin NPs were incorporated into an alginate/gelatin solution, prior to crosslinking using a calcium chloride solution (200 nM). These hydrogels were then characterised with respect to their chemical, mechanical and rheological properties. Following hydrogel optimization, hydrogels loaded with NP containing 2 % curcumin were selected as a candidate as a bioink for three-dimensional (3D) printing. The biological assessment for these bioinks/hydrogels were conducted using THP-1 cells, a human monocytic cell line. Cell viability and immunomodulation were evaluated using lactate dehydrogenase (LHD) and a tumour necrosis factor alpha (TNF-α) enzyme-linked immunosorbent (ELISA) assay, respectively. Results show that the hydrogels were cytocompatible and supressed the production of TNF-α. These bioactive hydrogels are printable, supress immune cell activation and inflammation showing immense potential for the fabrication of tissue engineering constructs.