Oneilthygesen6194
Bicontinuous microemulsions (BμEs) are a promising biomembrane mimetic system for investigating the behavior of antimicrobial peptides (AMPs) and their delivery to open wounds to combat antibiotic-resistant microorganisms. The properties of the BμE host are in turn affected by the guest AMP and can deviate from those of the unperturbed BμEs, especially at higher AMP concentrations. Here we report the effect of an archetypal AMP, melittin, over a wide range of concentrations, on the nanoscopic dynamics of BμEs formed by water/sodium dodecyl sulfate (SDS)/1-pentanol/dodecane, investigated using quasi-elastic neutron scattering (QENS). Two distinct motions are observed, namely, (i) the lateral motion of the surfactant on the surface of the oil channels and (ii) the internal motion of the surfactants. It is found that melittin restricts both the lateral and the internal motion, thereby acting as a stiffening agent. The lateral motion is more strongly affected, at low concentration of melittin. The lateral diffusiy therefore demonstrates how the addition of melittin hinders the lateral motion of surfactants as a result of the strong association between melittin and SDS, suggesting that the release of AMPs from BμE-based delivery vehicles may be hindered.The development of the efficient photocatalysts with improved photoexcited charge separation and transfer is an essential for the effective photocatalytic H2 generation using light energy. So far, owing to the unique properties and characteristics, the transition metal phosphides (TMPs) have been proven to be high performance co-catalysts to replace some of the classic precious metal materials in the photocatalytic water splitting. In the present work, we report a novel copper phosphide (Cu3P) as a co-catalyst to form a well-designed fabricated photocatalyst with blacktrumpet mushroom-like ZnS semiconductor for the first time. The synthesis of Cu3P/ZnS consists of two-step hydrothermal and ball milling methods. The physical properties of the materials so prepared were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analyses. In order to study the role of Cu3P, electrochemical impedance spectroscopy (EIS) measurements were used to investigate the photogenerated charge properties of ZnS. The experiments of photocatalytic production of H2 confirm that the Cu3P co-catalysts effectively promote the separation of photogenerated charge carriers in ZnS, and consequently enhance the H2 evolution activity. The 3% Cu3P/ZnS sample delivers the highest catalyst activity and the consistent H2 evolution rate is14,937 µmol h-1 g-1cat, which is 10-fold boosted compared to the pristine ZnS. The stability of the catalyst was tested by reusing the used 3% Cu3P/ZnS photocatalyst in five consecutive runs, and their respective activity in the H2 production activity was evaluated. A possible mechanism is proposed and discussed.Metal-organic framework (MOF) activation is crucial for the use of MOFs in several applications and solvent-exchange process is a necessary step in many activation methods. In this contribution, we have explored in situ MOF monolayer film formation at the air-water interface. Nanoparticles (NPs) of the Al trimesate MIL-96(Al) retain chloroform into their micropores, which considerably diminishes the CO2 adsorption capacity of MOF films. However, a solvent-exchange process between chloroform and water increases CO2 film adsorption capacity by 30%. Total Reflection X-Ray Fluorescence (TRXF) allows studying the kinetics of this process at the air-water interface, that strongly depends on the NP size. The conclusions derived from in situ studies allow optimizing the ex situ activation procedure of MIL-96(Al) films deposited onto quartz crystal microbalance (QCM) substrates in order to maximize CO2 and methanol adsorption.Metal free heterojunctions have shown promising applicability as potential photocatalyst materials. Like the commonly explored metal-non metal heterojunctions, semiconductor-semiconductor junctions are also capable of facilitating charge separation and improved lifetimes, leading to augmented surface reaction efficacy. WS6 However, unlike the metal carrying heterojunctions, they are much economical and easier to fabricate and tune. Through this study, we present a facile one step hydrothermal route to synthesize CuO-Cu2O nanorods/TiO2 nanoparticles heterostructures (CTHS) with their potential application as a low cost photocatalytic alternative. The average size of the synthesized heterojunction components, as estimated from transmission electron microscopy (TEM) evaluation was 13 and 5 nm respectively for the nanorod length and width, while the functionalizing TiO2 nanoparticles were averaged around 10 nm. Heterojunction formation was confirmed using Raman spectroscopy, X-ray diffraction, high resolution TEM, and elemental mapping. X-ray photoelectron spectroscopy data marked with presence of Cu+ and Cu+2 state of CuO in CuXO-TiO2 also supported junction formation. Optical characteristics of the heterojunction were studied using UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. Compared to TiO2 nanoparticles, CTHS exhibited superior sunlight-induced photodegradation activity. CuXO/TiO2 heterojunction could also remediate toxic waste water containing model antibiotic residue (Oxytetracycline hydrochloride, 0.4 mg/mL) and organic pollutant (methylene blue, 10 µM) in 20 and 60 min respectively. Ultra-fast degradation using a nonmetal heterojunction nanohybrid, like ours, finds negligible mention in literature. Improved visible light absorption and reduction in recombination rate for CuXO-TiO2 nanohybrids were ascribed as major contributing factors towards their enhanced photocatalytic potential. The charge separation mechanism for nanohybrids has been studied and elaborated in detail.Poor room-temperature ionic conductivity and lithium dendrite formation are the main issues of solid electrolytes. link2 In this work, rod-shaped alumina incorporation and graphite coating were simultaneously applied to poly (propylene carbonate) (PPC)-based polymer solid electrolytes (Wang et al., 2018). The obtained alumina modified solid electrolyte membrane (Al-SE) achieves a high ionic conductivity of 3.48 × 10-4 S/cm at room temperature with a wide electrochemical window of 4.6 V. The assembled NCM622/Al-SE/Li solid-state battery exhibits initial discharge capacities of 198.2 mAh/g and 177.5 mAh/g at the current density of 0.1 C and 0.5 C, with the remaining capacities of 165.8 mAh/g and 161.3 mAh/g after 100 cycles respectively. The rod-shaped structure of Al2O3 provides fast transport channels for lithium ions and its Lewis acidity promotes the dissociation of lithium salts and release of free lithium ions. The lithiophilic Al2O3 and Graphite form intimate contact with metallic Li and create fast Li+ conductive layers of Li-Al-O layer and LiC6 layer, thus facilitating the uniform deposition of Li and inhibiting Li dendrite formation during long-term cycling. This kind of composite Al-SE is expected to provide a promising alternative for practical application in solid electrolytes.
The secondary structure of proteins affects their functionality and performance in physiological environments or industrial applications. Change of the solution pH or the presence of protein denaturants are the main chemical means that can alter the secondary structure of proteins or lead to protein denaturation. Since proteins in the bulk solution and those residing at the solution/air interface experience different local environments, their response to chemical denaturation can be different.
We utilize circular dichroism and chiral/achiral sum frequency generation spectroscopy to study the secondary structure of selected proteins as a function of the solution pH or in the presence of 8M urea in the bulk solution and at the solution/air interface, respectively.
The liquid/air interface can enhance or decrease protein conformation stability. The change in the secondary structure of the surface adsorbed proteins in alkaline solutions occurs at pH values lower than those denaturing the studied proteins in the bulk solution. In contrast, while 8M urea completely denatures the studied proteins in the bulk solution, the liquid/air interface prevents the urea-induced denaturation of the surface adsorbed proteins by limiting the access of urea to the hydrophobic side chains of proteins protruding to air.
The liquid/air interface can enhance or decrease protein conformation stability. The change in the secondary structure of the surface adsorbed proteins in alkaline solutions occurs at pH values lower than those denaturing the studied proteins in the bulk solution. link3 In contrast, while 8 M urea completely denatures the studied proteins in the bulk solution, the liquid/air interface prevents the urea-induced denaturation of the surface adsorbed proteins by limiting the access of urea to the hydrophobic side chains of proteins protruding to air.Immobilization of single antioxidant enzyme systems was frequently studied in the past, however, there is a lack of reliable reports on the co-immobilization of such enzymes. Here, an antioxidant enzyme cascade involving superoxide dismutase (SOD) and horseradish peroxidase (HRP) was successfully immobilized on titania nanosheets (TNS) by the sequential adsorption method using poly(diallyldimethylammonium chloride) (PDADMAC) and poly(styrene sulfonate) (PSS) polyelectrolyte building blocks. The development of the cascade system was based on a colloid approach, in which the charging and aggregation processes were optimized in each synthetic step. The polyelectrolyte and enzyme multilayers were built up in two different sequences at the particle interface, namely, TNS-PDADMAC-SOD-PSS-HRP and TNS-HRP-PDADMAC-SOD-PSS. The formation of the polyelectrolyte layers led to charge reversal of the carrier and the saturated PDADMAC and PSS layers stabilized the dispersions, in particular, their resistance against salt-induced aggregation was especially excellent. The results of enzymatic assays revealed that the SOD and HRP-like activities of the composites depended on the location of the enzymes in the hybrid material. The obtained compounds showed remarkable antioxidant effect and were able to simultaneously decompose superoxide radical anions and hydrogen peroxide. The cascade systems are of great promise in industrial manufacturing processes during the preparation of high-quality products without any damages by reactive oxygen species.Potential strategies such as surface passivation and perovskite material halide mixing may protect material surfaces, improve luminescence, and reduce charge traps for device stability. In this study, we used deep level transient spectroscopy to investigate the effect of CdSe/ZnS core-shell quantum dots (QDs) on defect states and carrier transport in methylammonium (MA) lead halide perovskites (CH3NH3PbX3 where X = I, Br). In MAPbI3 and MAPbI2Br films with CdSe/ZnS QDs, the density of hole traps located at Ev + 0.37 eV and Ev + 0.56 eV was reduced dramatically. Deep traps at Ev + 0.78 eV and Ev + 1.08 eV were removed, and one broad electron trap signal dominated. Film photoresponsivity under 600-nm wavelength light and a bias voltage of -0.7 V was 10 and 18 mA/W, which is 100 and 27 times larger than the 0.1 and 0.67 mA/W of bare perovskites (PS), respectively. This demonstrates that carrier transport was enhanced due to defect suppression. Our findings on defect suppression and photoresponsivity enhancement provide an important direction for optimizing high-performance PS device fabrication.