Attenuated Total Reflection Infrared Research Articles

Laser-irradiating infrared attenuated total reflection spectroscopy of articular cartilage: Potential and challenges for diagnosing osteoarthritis

ObjectiveA prototype infrared attenuated total reflection (IR-ATR) laser spectroscopic system designed for in vivo classification of human cartilage tissue according to its histological health status during arthroscopic surgery is presented. Prior to real-world in vivo applications, this so-called osteoarthritis (OA) scanner has been tested at in vitro conditions revealing the challenges associated with complex sample matrices and the accordingly obtained sparse spectral datasets. MethodsIn vitro studies on human knee cartilage samples at different contact pressures (i.e., 0.2–0.5 ​MPa) allowed recording cartilage degeneration characteristic IR signatures comparable to in vivo conditions with high temporal resolution. Afterwards, the cartilage samples were assessed based on the clinically acknowledged osteoarthritis cartilage histopathology assessment (OARSI) system and correlated with the obtained sparse IR data. ResultsAmide and carbohydrate signal behavior was observed to be almost identical between the obtained sparse IR data and previously measured FTIR data used for sparse partial least squares discriminant analysis (SPLSDA) to identify the spectral regions relevant to cartilage condition. Contact pressures between 0.3 and 0.4 ​MPa seem to provide the best sparse IR spectra for cylindrical (d ​= ​3 ​mm) probe tips. ConclusionLaser-irradiating IR-ATR spectroscopy is a promising analytical technique for future arthroscopic applications to differentiate healthy and osteoarthritic cartilage tissue. However, this study also revealed that the flexible connection between the laser-based analyzer and the arthroscopic ATR-probe via IR-transparent fiberoptic cables may affect the robustness of the obtained IR data and requires further improvements.

Enhancing biological properties with straightforward deposition of durable heparin/chitosan surface coatings on wettable poly(ε-caprolactone)/Tween-20 electrospun fibers

Poly(ε-caprolactone) (PCL) is a hydrophobic aliphatic polyester commonly used as a biomaterial due to its cytocompatibility and biodegradability. However, PCL-based materials are hydrophobic and susceptible to bacterial adhesion and proliferation. To address these disadvantages, this study proposes a direct and practical method for functionalizing the surface and enhancing the biological properties of electrospun PCL fibers using Tween-20 surfactant, followed by the deposition of polyelectrolyte multilayers (PEMs). Tween-20, a neutral and cytocompatible surfactant, was directly incorporated into the fibers without prior surface modifications. The surfactant significantly increased the wettability of the PCL fibers, resulting in water contact angles of 0 degrees, facilitating subsequent functionalization with heparin and chitosan PEMs (with 10, 20, and 30 layers). The materials were characterized through scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), water contact angle and mechanical measurements, Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The PEMs remain stable on the fiber surfaces for up to 14 days in a buffer at 37°C. The samples supported high cell viability with no observed cytotoxicity toward human adipose-derived stem cells and no hemolytic activity toward human red blood cells. Antibacterial assays (live/dead and proliferation tests) demonstrated that the coated PCL fibers inhibited the proliferation of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). The PEM coatings significantly enhanced the antimicrobial activity, resulting in a high number of damaged and dead bacterial cells attached to the coated fibers. Therefore, the heparin/chitosan PEMs on Tween-20-modified PCL fibers can prevent bacterial infections while supporting viable mammalian cells.

Development and Characterization of Gadolinium and Copper Reinforced Bioactive Glass: An In Vitro Study.

Bioactive glass, an innovative alloplastic material utilizing a matrix of silica particles combined with calcium and phosphorus, has been widely employed for the regeneration of bony defects due to its bone-forming capabilities and biocompatibility. Nevertheless, it comes with several drawbacks, including a slow degradation rate, low mechanical strength, and susceptibility to fractures. To address these issues, the present research was done to develop and characterize a novel bioactive glass incorporating gadolinium (Gd) and copper (Cu). The bioactive glass doped with Gd and Cu were synthesized and subjected to characterization through X-ray diffraction (XRD), scanning electron microscopy (SEM), and attenuated total reflectance-infrared (ATR-IR) analysis. The bioactive glass, enriched with Gd and Cu, underwent analysis using ATR-IR spectroscopy, XRD, and SEM. ATR-IR revealed characteristic silicate bands, while SEM indicated the presence of particles larger than 4 μm. XRD analysis identified the formation of Na2Ca4(PO4)2SiO4 (Silicorhenatite), Na2Ca2Si3O9 (Combeite), and wollastonite (calcium inosilicate mineral; CaSiO3). The crystalline nature of these compounds contributed to the favorable mechanical properties of the bioactive glass. In summary, the creation of the innovative Gd-Cu-incorporated bioactive glass demonstrates favorable mechanical characteristics, suggesting significant promise for augmenting bone regeneration.

Lignocellulosic Membranes Grafted with N-Vinylcaprolactam Using Radiation Chemistry: Load and Release Capacity of Vancomycin.

Radiation chemistry presents a unique avenue for developing innovative polymeric materials with desirable properties, eliminating the need for chemical initiators, which can be potentially detrimental, especially in sensitive sectors like medicine. In this investigation, we employed a radiation-induced graft polymerization process with N-vinylcaprolactam (NVCL) to modify lignocellulosic membranes derived from Agave salmiana, commonly known as maguey. The membranes underwent thorough characterization employing diverse techniques, including contact angle measurement, degree of swelling, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), nuclear magnetic resonance (CP-MAS 13C-NMR), X-ray photoelectron spectroscopy (XPS), and uniaxial tensile mechanical tests. The membranes' ability to load and release an antimicrobial glycopeptide drug was assessed, revealing significant enhancements in both drug loading and sustained release. The grafting of PNVCL contributed to prolonged sustained release by decreasing the drug release rate at temperatures above the LCST. The release profiles were analyzed using the Higuchi, Peppas-Sahlin, and Korsmeyer-Peppas models, suggesting a Fickian transport mechanism as indicated by the Korsmeyer-Peppas model.

RAPID DETECTION OF RAT MEAT ADULTERATION IN BEEF SAUSAGES USING FTIR‑ATR SPECTROSCOPY AND CHEMOMETRICS FOR HALAL AUTHENTICATION

Objective: The objective of this study was to employ Fourier Transform Infrared-Attenuated Total Reflectance (FTIR‑ATR) spectroscopy in combination with chemometrics for the analysis of rat meat adulteration in beef sausages.
 Methods: Lipid components in sausages were extracted using three extraction methods, namely Bligh and Dyer, Folch, and Soxhlet methods. The lipid components extracted were then analysed using FTIR‑ATR spectroscopy, and their spectra obtained were used as variables during chemometrics modeling. Samples were prepared by mixing beef with adulterant of rat meat in the concentration range of 0-100% of rat meat. Each sample was scanned using FTIR-Attenuated Total Reflectance (ATR) spectroscopy in three replicates at 4000-650 cm-1 wavenumber region.
 Results: The absorbance values at wavenumbers regions of 3100-700 cm-1 were used to discriminate lipid components extracted by the Bligh Dyer, Folch, and Soxhlet Method with an accuracy level of 100%. The prediction of rat sausages was successfully determined using multivariate calibrations of Partial Least Square (PLS) and Principle Component Regression (PCR) using optimised conditions.
 Conclusion: FTIR-ATR spectroscopy coupled with chemometrics is a rapid and accurate method for detecting and quantifying rat meat in beef sausages for halal authentication.

Rapid photocatalytic disruption of Chlorella vulgaris cells for extraction of triacylgricides using Ag3PO4–TiO2 nanocomposite

Freshwater green microalgae are a source of valuable industrial products. Owing to the lipid accumulating nature of these organisms, it is among the most promising solutions to meet carbon neutral hydrocarbon fuel needs for future transportation. However, there are many technical hurdles that need to be overcome before their commercial viability. One of the challenges is getting cellular lipids out from the cell because of the sturdy algal cell wall. Several chemical, physical, thermal, and biological techniques have been tested and reported so far, but all the methods are either energy intensive, not scalable, product damaging, slow or less effective. Photocatalysis is a promising field with emerging green solutions to many environmental problems and has only scarcely been studied so far for algal cell disruption. In this study Ag3PO4–TiO2 photocatalyst was used for pre-treatment of Chlorella vulgaris (UTEX-26) cells in the presence of UV and visible light. Results showed an increase of ∼8% in lipid quantity compared to raw cells with 5 and 30 min of UV and visible light pre-treatment, respectively at a catalyst dose of 500 mg L−1 at pH 3. The Attenuated Total Reflection - Infra Red (ATR-IR) analysis of bio-oil revealed that no significant change in lipid quality occurred due to photocatalytic pre-treatment. The pre-treatment experiments also resulted in simultaneous harvesting of the cells, thus further reducing the energy needs of the process. The technique for algal cell wall disruption using Ag3PO4–Titania composites for lipid yield enhancement has not been reported to date.

Non-invasive optical property-based strategy to distinguish poly(ethylene terephthalate) containers of different recycled content

For Poly(ethylene terephthalate) (PET), one of the most widely used and re-used plastics, no definitive analytical method has been established to distinguish between the virgin form and its recycled counterpart. Numerous efforts have been made to achieve this purpose by mainly measuring thermal or mechanical properties and in this sense, the challenge arises from the fact that several factors can affect the characteristics of PET, recycled or not. In this study, the optical properties and their correlations for 28 PET containers with different mass, thickness and content of recycled material have been studied, normalized and parameterized to ultimately differentiate between both forms. Diffuse reflectance UV–Vis (DRS) spectra were unique for each sample and, while near-infrared (NIR) and Fourier-transform infrared-attenuated total reflectance (FT-IR-ATR) provided constant overall parameters regardless of the recycled %, fluorescence and Raman results indicated some differences between non-recycled and recycled PET. Furthermore, the Raman identification accuracy of the two groups was 96.4% and the fluorescence intensity could be related to the content of recycled PET. Moreover, water permeability tests were carried out on some samples, concluding that this property was correlated with the thickness of the plastic and not the recycled %. The study was completed by performing a multivariate analysis (PCA, box plot, K-means and hierarchical clustering analysis) to better understand the correlations within the variables studied and finally confirm the selection of those that allowed for a correct and sequential discrimination of the groups, resulting in a fast and non-invasive strategy that allows for an almost complete vPET-rPET distinction.

In situ Fourier transform infrared-attenuated total reflection spectroscopy and modeling investigation of protein adsorption: Case of expanded bovine serum albumin on titanium dioxide anatase.

The purpose of this experimental and modeling research is to study the pH effect and to determine the surface coverage plus the adsorption constant (Ka) of bovine serum albumin (BSA) protein adsorbed on TiO2 anatase surface, respectively. In situ Fourier transform infrared-attenuated total reflection spectroscopy in a flow-through cell was used to study the BSA adsorption on porous TiO2 anatase films. The experiments were performed in water solution, under different pH values, at a concentration of 10-6 mol/l. Theoretically, we extended the two-state model, based on a system of coupled differential equations, by adding a desorption parameter Kd2, for unfolded state. The model was solved taking into account the adsorption (Ka), desorption (Kd1,2), transformation (Kf) coefficients, and the initial solution protein concentration (C0). The findings clearly illustrated that the solution pH drastically changed the behavior of BSA adsorption, whereas the mathematical analytical solutions allowed us to determine the native state (θ1), the unfolded state (θ2), and the full one (θ) surface coverages. Finally, a good application of the approximated model on the experimental work, expanded BSA adsorbed on TiO2 anatase at pH = 1.7, indicated a value of Ka = (408.36 ± 0.996) × 102 mol-1 l min-1.

Efficient, fast, simple, and eco-friendly methods for separation of toxic chromium(VI) ions based on ion exchangers and polymer materials impregnated with Cyphos IL 101, Cyphos IL 104, or D2EHPA

In this study, we present the results of the first comparison of the elimination of toxic Cr(VI) ions, which are hazardous contamination of the environment, from aqueous solutions using ion exchangers (IEs) and polymer materials (PMs) impregnated with D2EHPA or ionic liquids (Cyphos IL 101 and Cyphos IL 104). Sorption of Cr(VI) ions and desorption from the formulated sorption materials were carried out. In comparison, classical solvent extraction was accomplished. Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and atomic force microscopy (AFM) have been used for characterization of the structure of developed IEs and PMs. The highest efficiency of adsorption of Cr(VI) ions was obtained using PMs with ionic liquids (>82%). Desorption from these materials were also very efficient (>75%). On the contrary, the application of IEs allowed for obtaining the best results of both, sorption and desorption processes when using D2EHPA (75% and 72%, respectively). The application of PMs and IEs is part of the green chemistry, and the conducted elimination of chromium(VI) ions using developed materials allows for the conclusion that they can potentially be used on a larger scale, e.g., for the treatment of industrial wastewater rich in Cr(VI) ions.

DrogoFinder: An open-source graphical user interface for the identification of illicit drugs using infrared spectroscopy

The development of Free and Open-Source Software (FOSS) is being increasingly recognized as an indispensable resource for the development, validation, and replication of analytical methodologies and tools. In this context, the use of Attenuated Total Reflectance Infrared (ATR-IR) spectroscopy for the in-situ identification of drugs requires software for the treatment of spectroscopic data, including spectral quality controls, the subtraction of possible excipients, and the comparison with well-defined libraries that can be complex and limits its application on the field analysis by non-expert users. Here we describe a user-friendly FOSS for drug identification that can be operated in an intuitive way, including automatic features such as i) quality controls that warn the user from possible technical problems during spectrum acquisition (e.g. water vapour, contaminated background), ii) the subtraction of the contribution of excipients and other substances present on the sample, and iii) the creation of custom and updated cloud-based libraries to deal with the great number of new psychoactive substances (NPS) that are constantly being developed and introduced for their consume. The proposed application was tested by expert and non-expert users with spectra from 42 drug samples measured in situ in a music festival and 39 seized samples measured in a laboratory. Non-expert users were able to flag technical problems in the spectra and to perform excipient subtractions automatically, obtaining drug identifications that matched those ones obtained by reference methods and dedicated commercial software. We share both, the code, and a standalone Windows app to reach worldwide users and scientists interested in the identification of drugs.

Heterogeneous Cobalt Phthalocyanine/Sulfur‐Modified Hollow Carbon Sphere for Boosting CO2 Electroreduction and Zn–CO2 Batteries

AbstractTuning coordination environment of single‐atom catalysts (SACs) is widely applied for the electrochemical CO2 reduction reaction (CO2RR). However, the influence of the interaction between SACs and support on the catalytic performance are not comprehensive. Herein, taking cobalt phthalocyanine (CoPc) as a conceptual example, a hetero S‐atom doping strategy of hollow carbon sphere (S‐NHC) is put forward as a carrier, revealing the intrinsic relationship between microenvironment regulation and catalytic activity of single Co‐atom. The additional S doping may induce more carbon defect and increases the content of pyrrolic N in the S‐NHC sample, leading to stronger electronic interaction of heterogeneous CoPc/S‐NHC for boosting CO2RR performance. Remarkably, the catalyst achieves a highest CO selectivity of nearly 100% at −0.6 V, and the FECO are over 90% in a wide potential range from −0.4 to −0.8 V in a flow cell. The maximum power density is high as 2.68 mW cm−2 at 4.7 mA cm−2 for the Zn–CO2 battery with CoPc/S‐NHC cathode. In situ attenuated total reflection infrared (ATR‐IR) spectroscopy reveals the formation of key *COOH and *CO intermediates, while the calculation result confirm the optimized Gibbs free energy of these intermediates on CoPc/S‐NHC, suggesting the feasibility of the regulation strategy.

In-situ growth coating of MIL-88/100(Fe) on carbon cloth for adsorption and photocatalytic degradation of Methylene Blue

The majority of efficient photocatalysts are powder-like, making recycling difficult. In this work, carbon cloth (CC) was used as the substrate, two MOF cloth composites MIL-88@CC and MIL-100@CC were prepared at room temperature, and the morphology and structure of MOF cloth composites were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared-attenuated total reflectance (FTIR), X-ray photoelectron spectroscopy (XPS). The results of photocatalytic degradation tests show that the two heat-treated MOF cloth composites have excellent degradation effects on MB. The two MOF cloth composites can degrade above 97 % of MB (20 mg/L) within 30 min under the irradiation of 250 W high-pressure mercury lamp and stirring, far exceeding the raw MOF cloth. The presence of oxygen vacancy defects is thought to have improved the heat-treated MOF cloth's photocatalytic efficiency by upsetting the symmetry of the material and facilitating electron and hole separation.·OH and·O2- were found to be the main reactive oxygen species (ROS) involved in the degradation process, according to quenching studies and electron spin resonance (ESR) research. In addition, the macroscale MIL-88@CC and MIL-100@CC have considerable potential for degrading dyes, which presents a practical solution to sustainable development concerns.

Chemical and Nutritional Fat Profile of Acheta domesticus, Gryllus bimaculatus, Tenebrio molitor and Rhynchophorus ferrugineus.

The use of edible insects in the human diet is gaining importance because they are characterized by high nutritional value, and their cultivation is much more environmentally friendly than traditional livestock farming. The objective of this study was to determine the chemical and nutritional fat profile of selected edible insects as follows: house cricket (Acheta domesticus adult), field cricket (Gryllus bimaculatus adult), mealworm (Tenebrio molitor larvae), and palm weevil (Rhynchophorus ferrugineus larvae) which are now commercially available worldwide. Additionally, the degree of implementation of nutrition standards for selected nutrients by these insects was assessed. Freeze-dried insects were studied using infrared-attenuated total reflectance mid-infrared spectroscopy for basic differentiation. The content of fat and fatty acids was determined, and dietary indicators were calculated. The spectroscopic findings align with biochemical data, revealing that Rhynchophorus ferrugineus larvae contain the highest fat content and the least protein. Unsaturated fatty acids (UFAs) predominated in the fat of the assessed insects. The highest content of saturated fatty acids (SFAs), along with the lowest content of polyunsaturated fatty acids (PUFAs), was observed in the larvae of the Rhynchophorus ferrugineus species. From a nutritional standpoint, Tenebrio molitor larvae exhibit the most favorable indicators, characterized by minimal athero- and thrombogenic effects, along with an optimal balance of hypo- and hypercholesterolemic acids. Knowledge of the composition and quantities of fats in different insect species is valuable for planning and preparing meals with accurate nutritional profiles, among other applications.

Enhanced removal of perfluoroalkyl substances using MMO-TiO2 visible light photocatalyst

Exploration of easily produced visible light photocatalysts is still necessary. Thus, this study investigated the catalytic performance of a mixed metal oxide-titanium dioxide (MMO-TiO2) to remove perfluorooctanoic acid (PFOA), a typical and harmful perfluoroalkyl substance, under visible light conditions. Analysis of degradation efficiencies revealed that MMO-TiO2 exhibited a remarkable removal efficiency of 95.99 ± 1.49 %, surpassing other catalysts, including TiO2, ZnAl, MMO, and ZnAl-TiO2. MMO-TiO2, derived from ZnAl-TiO2 calcination, displayed a 5.66-fold higher apparent degradation rate constant (1.07 × 10−2 min−1) compared to ZnAl-TiO2 (1.89 × 10−3 min−1). These materials were characterized via X-ray powder diffractometry, Fourier transform infrared-attenuated total reflectance, N2 adsorption-desorption analysis, and field emission-scanning electron microscopy. Results revealed that O2•- radicals play a pivotal role as the predominant species that mediate PFOA removal. Comparative experiments using probe compounds confirmed increased O2•- production during MMO-TiO2 photoreaction under visible light. In addition, this study explored the effect of operational parameters, such as catalyst dose, initial PFOA concentration, solution pH, and water matrices on the photocatalytic removal process. These findings provide insight into the removal of PFOA using MMO-TiO2, highlighting the potential of this visible light catalyst for the eco-friendly removal of persistent organic pollutants in aquatic systems.

Thermoelectric properties investigation of Tungsten carbide-filled poly (vinyl alcohol)/Polypyrrole ternary composites

ABSTRACT Many researchers have recently focused their attention on conductive polymer-based flexible thermoelectric (TE) materials. One of the most popular approaches for improving TE efficiency is the addition of inorganic components to conductive polymers. In this work, the TE properties of tungsten carbide-filled poly (vinyl alcohol)/polypyrrole (PVA/PPy/WC) ternary composites were examined for the first time. First, composites with varying WC weight ratios were produced by the solvent casting process. Scanning electron microscopy (SEM) investigations demonstrated the homogenous dispersion of WC particles in the composite structure, while X-ray diffraction (XRD) analyses determined the influence of WC addition on the crystal structure of the composite. The electrostatic interactions of each component were revealed by Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR) and UV-vis studies. Additionally, with the addition of WC, the energy bandgap of PVA/PPy reduced from 5.71 eV up to 2.07 eV. From TE studies, it was obtained that the electrical conductivity of PVA/PPy increased from 3.35 × 10−3 up to 58 Sm−1 with the addition of 30% WC, while the power factor (PF) of PVA/PPy increased from 8,6 × 10−9 μWm−1K−2 up to 1.71 × 10−3 μWm−1K−2. Both composite samples had negative Seebeck coefficients, which are typical of n-type conductors.

Thermal Gradient Infrared Spectroscopy for Diffusion in Polymers.

Time-resolved Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR) was used to measure diffusion in opaque and translucent samples. FTIR-ATR was used to measure the change in the absorbance near the heated ATR crystal surface. The infrared absorbance was then related to the concentration through the Beer-Lambert law. The sample used is a polymer electrolyte composed of lithium bis-trifluoromethanesulfonylimide (LiTFSI) salt in a block copolymer polystyrene-poly(ethylene oxide) (SEO). A new approach to introduce concentration gradients is presented using a temperature gradient that creates a small salt concentration gradient due to thermally driven mass diffusion (the Soret effect). This first method was compared to a second method that we reported using two laminated polymer electrolyte films of different salt concentrations. The thermal gradient study (method 1) covered three temperature differences of 10, 15, and 20 °C, while the second study (method 2) used three average molar ratios across isothermal temperatures ranging from 80 to 120 °C. The benefits and limitations of the new approach are reported, as is the activation energy for salt diffusion in this and similar SEO electrolytes. Developing new techniques to measure diffusion coefficients effectively will aid in the development of a variety of devices, including solid-state batteries and thermogalvanic cells, that are able to convert waste heat into electricity and improve the efficiency of power-generating systems. FTIR-ATR overcomes previous limitations in experimental techniques measuring diffusion coefficients. The results prove that thermal gradient FTIR-ATR is an effective and repeatable approach for determining Fickian diffusion coefficients in viscoelastic solids.

Creating Nature-Inspired Surface Roughness and Modifying Surface Chemistry of PVDF Electrospun Fibers Using Low-Pressure Plasma towards Omniphobic Membrane for Long-term Distillation

Today, water scarcity as one of the world's most pressing challenges, has caused many concerns. Seawater desalination based on membrane distillation (MD) has been introduced as an effective solution to deal with this problem. The surface of membranes used in MD is required to be modified to guarantee long-term performance via creating resistance against membrane wetting by low surface tension feeds. In this regard, beetle skin-inspired roughness was created on the surface of poly(vinylidene fluoride) (PVDF) electrospun fibers using low-pressure plasma technique. Synergistically, 1H, 1H, 2H, 2H-perfluorooctyl acrylate (PFOA) was polymerized on the fiber surface to modify its chemistry. In other words, using the plasma polymerization technique, the membrane surface energy was reduced thanks to (1) the increase in membrane surface roughness and (2) the change in the membrane surface chemistry, as confirmed by field-emission scanning electron microscope (FESEM) imaging, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. These changes led to an omniphobic membrane repelling water, engine oil and isopropanol with contact angles of 150°, 135°, and 119°, respectively. The long-term performance of the developed omniphobic membrane was demonstrated by conducting air gap membrane distillation (AGMD) for a duration as long as 600 min using a feed solution containing 3.5 wt% NaCl and 0.6 mM sodium dodecyl sulfate (SDS), which is ten times better than the performance of pristine membrane (60 min). Overall, the surface modification technique considered in this work yields an omniphobic membrane with stable long-term performance without compromising the membrane flux and salt rejection.

Pd "Kills Two Birds with One Stone" for the Synthesis of Catalyst: Dual Active Sites of Pd Triggers the Kinetics of O2 Electrocatalysis.

Noble metal-based catalyst, despite their exorbitant cost, are the only successful catalyst for bifunctional oxygen electrocatalysis owing to their capability to drive forward the reaction rate kinetically. Therefore, it is desirable to diminish the noble metal loading without any compromise in the catalyst performance. In this study, the aim to achieve two goals with one action via a single-step route to have ultra-low loading of Pd in the catalyst. The Pd is used as a catalyst for C─C bond formation followed by complexation reactions or vice versa, in conventional Suzuki-Miyaura cross-coupling (SMCC) reaction, which yields a Pd-based porous organic polymer. Interestingly, it is found that dispersed Pd nanocluster (PdNC ) is present together with Pd single atom doped into nanocarbon (Pd-NC) matrix in the catalyst (PdNC /Pd-NC800 ) that obtained after pyrolysis of the porous polymer. The catalyst exhibits remarkable bifunctional activity and durability towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Further, it is studied that the in situ attenuated total reflection infrared (ATR-IR) spectroscopy at different electrochemical potentials during ORR and OER to observe the reaction intermediates. The homemade zinc-air battery with the catalyst displayed great performance, establishing the significance of PdNC /Pd-NC800 as a bifunctional oxygen electrocatalyst.

Development of bio-based expanded cork polymer composites (eCPC) with poly(lactic acid) (PLA)

Expanded cork polymer composites (eCPC) using a PLA matrix and expandable microspheres (EMS) were developed and characterized. A blowing agent was introduced to evaluate its effect on cork structure in eCPC injected pieces. A chemical and thermal characterization was conducted using Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) to investigate the effect of cork and EMS in eCPC. The results have shown that the introduction of cork and EMS led to composites with up to 8% less density and with lower temperature of cold crystallization. The presence of cork in CPC and eCPC allowed to lower the cold crystallization temperature by almost 13 ºC. It was found an increase on the crystallinity degree in the presence of cork and EMS. Scanning Electron Microscopy (SEM) was used to perform morphological studies. A recovered alveolar structure was found for cork cells in eCPC injected pieces.

Antimicrobial susceptibility testing using infrared attenuated total reflection (IR-ATR) spectroscopy to monitor metabolic activity

Fast and accurate detection of antimicrobial resistance in pathogens remains a challenge, and with the increase in antimicrobial resistance due to mis- and overuse of antibiotics, it has become an urgent public health problem. We demonstrate how infrared attenuated total reflection (IR-ATR) can be used as a simple method for assessment of bacterial susceptibility to antibiotics. This is achieved by monitoring the metabolic activities of bacterial cells via nutrient consumption and using this as an indicator of bacterial viability. Principal component analysis of the obtained spectra provides a tool for fast and simple discrimination of antimicrobial resistance in the acquired data. We demonstrate this concept using four bacterial strains and four different antibiotics, showing that the change in glucose concentration in the growth medium after 2 h, as monitored by IR-ATR, can be used as a spectroscopic diagnostic technique, to reduce detection time and to improve quality in the assessment of antimicrobial resistance in pathogens.