To investigate the safety and efficacy of subretinal injection of human Wharton's Jelly-derived mesenchymal stem cells (hWJ-MSCs) on retinal structure and function in Royal College of Surgeons (RCS) ...rats.
RCS rats were divided into 2 groups: hWJ-MSCs treated group (n = 8) and placebo control group (n = 8). In the treatment group, hWJ-MSCs from healthy donors were injected into the subretinal space in one eye of each rat at day 21. Control group received saline injection of the same volume. Additional 3 animals were injected with nanogold-labelled stem cells for in vivo tracking of cells localisation using a micro-computed tomography (microCT). Retinal function was assessed by electroretinography (ERG) 3 days before the injection and repeated at days 15, 30 and 70 after the injection. Eyes were collected at day 70 for histology, cellular and molecular studies.
No retinal tumor formation was detected by histology during the study period. MicroCT scans showed that hWJ-MSCs stayed localised in the eye with no systemic migration. Transmission electron microscopy showed that nanogold-labelled cells were located within the subretinal space. Histology showed preservation of the outer nuclear layer (ONL) in the treated group but not in the control group. However, there were no significant differences in the ERG responses between the groups. Confocal microscopy showed evidence of hWJ-MSCs expressing markers for photoreceptor, Müller cells and bipolar cells.
Subretinal injection of hWJ-MSCs delay the loss of the ONL in RCS rats. hWJ-MSCs appears to be safe and has potential to differentiate into retinal-like cells. The potential of this cell-based therapy for the treatment of retinal dystrophies warrants further studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this study, two biomass-based adsorbents were used as new precursors for optimizing synthesis conditions of a cost-effective powdered activated carbon (PAC). The PAC removed dyes from an aqueous ...solution using carbonization and activation by KOH, NaOH, and H
SO
. The optimum synthesis, activation temperature, time and impregnation ratio, removal rate, and uptake capacity were determined. The optimum PAC was analyzed and characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), Zeta potential, and Raman spectroscopy. Morphological studies showed single-layered planes with highly porous surfaces, especially PAC activated by NaOH and H
SO
. The results showed that the experimental data were well-fitted with a pseudo-second-order model. Based on Langmuir isotherm, the maximum adsorption capacity for removing methylene blue (MB) was 769.23 mg g
and 458.43 mg g
for congo red (CR). Based on the isotherm models, more than one mechanism was involved in the adsorption process, monolayer for the anionic dye and multilayer for the cationic dye. Elovich and intraparticle diffusion kinetic models showed that rubber seed shells (RSS) has higher α values with a greater tendency to adsorb dyes compared to rubber seed (RS). A thermodynamic study showed that both dyes' adsorption process was spontaneous and exothermic due to the negative values of the enthalpy (ΔH) and Gibbs free energy (ΔG). The change in removal efficiency of adsorbent for regeneration study was observed in the seventh cycles, with a 3% decline in the CR and 2% decline in MB removal performance. This study showed that the presence of functional groups and active sites on the produced adsorbent (hydroxyl, alkoxy, carboxyl, and π - π) contributed to its considerable affinity for adsorption in dye removal. Therefore, the optimum PAC can serve as efficient and cost-effective adsorbents to remove dyes from industrial wastewater.
•Electrocatalytic reduction of nitrate ions has been performed at Pt–Cu surface.•The Pt–Cu surface is more efficient than a pure Cu or Pt surface.•The Pt–Cu catalyst exhibits stable performance in ...the neutral medium.•The existence of Pd particles onto the Pt–Cu surface improves the catalytic efficiency.
The electrocatalytic reduction of NO3− and its intermediate NO2− in neutral medium was performed at a Cu-immobilized Pt surface. The voltammetric investigations showed that the bare Cu electrode has little effect on nitrate reduction reactions (NRR) whereas an enhanced catalytic effect (i.e. a positive shift of the peak potential and an increased reduction current) was observed when Cu particles were immobilized onto Pt surface. At the Cu–Pt electrode surface, the NRR process was observed to occur via a two-step reduction mechanism with a transfer of 2 and 6 electrons in the first and second steps, respectively. Similar results were obtained by chronoamperometric (CA) studies. Closer NRR mechanistic studies at the as prepared Cu–Pt electrode revealed concentration-dependent kinetics with a “critical” nitrate ion concentration of ca. 0.02M. Moreover, NRR proceeded via a simple adsorption–desorption mechanism following a Langmuir isotherm with an adsorption Gibbs free-energy of ca. −10.16kJmol−1 (1st step) and ca. −10.05kJmol−1 (2nd step). By means of a Pt|Nafion|Cu–Pt type reactor without any supporting electrolyte, bulk electrolysis was performed to identify nitrate reduction products. It was found that after 180min of electrolysis, 51% of NO3− was converted into NO2− intermediate. This percentage decreased to 30% in CO2 buffered conditions. However, when a tri-metallic Pt–Pd–Cu electrode was employed as a cathode, all of the NO2− produced could be successfully converted into NH3 and N2. The electrocatalysis of nitrate ion on Cu–Pt electrode surface showed no apparent surface poisoning as confirmed by its stability after excessive CV runs. This was further supported by surface analysis and morphology of the as-prepared catalyst with scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis.
•ZnO-NPs were deposited onto cotton fibers via ultrasound irradiation.•Surfactants have stabilized the coated ZnO-NPs, controlling their shape and size as encapsulated species.•The use of surfactants ...has increased the durability of cotton coated ZnO-NPs and decreased its leaching.•ZnO-SDS and ZnO-HY was the most effective systems in reduction of the antimicrobial activities.•SEM and XRD analysis revealed that shape and size of the coated ZnO-nanoparticles.
ZnO NPs were prepared and deposited onto cotton fibers via ultrasound irradiation successfully. Different surfactants (SDS, HY, CTAB, TX-100) have been used to stabilize, homogenize the coated ZnO NPs and control their shape and size as encapsulated species. The use of surfactants has improved the durability of ZnO NPs and decreased its leaching in particular SDS. The small mean crystallite size for ZnO particles due to the use of surfactants is the main reason for decreasing the leached of ZnO particles from cotton substrate. SEM and XRD analysis revealed information about the shape and size of the coated ZnO nanoparticles. The use of SDS and HY surfactants in the synthesis of ZnO NPs coated fabrics showed the highest antibacterial and antifungal activities against different pathogenic bacterial and fungal species with high reduction reached over 90%.
A thorough characterisation of the genetics, physiology and metabolism of Escherichia coli has led to the availability of a large number of strains and vectors suitable for recombinant protein ...expression. Despite the relative ease in using E. coli for achieving amplified expression of many recombinant proteins, for some proteins this can be a frustrating and time-consuming process leading to very low expression or no expression at all. This is especially true for membrane proteins, which introduce additional challenges. A number of factors can be considered and optimised for achieving required levels of amplified expression of recombinant proteins in E. coli that are broadly classified as host strain, expression vector and growth conditions. In this paper we summarise these factors and consolidate the common challenges encountered and approaches to overcome them, focusing in particular on cases where there is low amplified expression or no expression at all of the desired recombinant protein, due to various reasons.
•Escherichia coli is the most widely used organism for amplifying recombinant protein expression.•This is challenging for some proteins, giving low expression or no expression at all.•Different parameters can be altered for optimising recombinant protein production.•These include the host strain, the expression vector and growth conditions.•Issues at the DNA level and protein toxicity/aggregation/instability can be overcome.
The potentials of biomass-based carbon quantum dot (CQD) as an adsorbent for batch adsorption of dyes and its photocatalytic degradation capacity for dyes which are congo red (CR) and methylene blue ...(MB) have been conducted in this study. The CQDs properties, performance, behaviour, and photoluminescence characteristics were assessed using batch adsorption experiments which were carried out under operating conditions including, temperature, pH and dosage. The morphological analysis revealed that CQDs are highly porous, uniform, closely aligned and multi-layered. The presence of hydroxyl, carboxyl and carbonyl functional groups indicated the significance of the oxygenated functional groups. Spectral analysis of photoluminescence for CQDs confirmed their photoluminescent quality by exhibiting high excitation intensity and possessing greenish-blue fluorescence under UV radiation. The removal percentage of the dyes adsorbed for both CR and MB dyes was 77% and 75%. Langmuir isotherm and pseudo-second-order models closely fitted the adsorption results. Thermodynamics analysis indicated that the adsorption process was exothermic and spontaneous, with excellent reusability and stability. The degradation efficiency of CQDs on both dyes was more than 90% under sunlight irradiation and obeyed the first-order kinetic model. These results demonstrated CQDs to be an excellent adsorbent and outstanding photocatalyst for organic dye degradation.
Controllable synthesis of organic thin film materials on solid surfaces is a challenging issue in the research field of surface science, as it is affected by several physical parameters. In this ...work, we demonstrated a solution-based molecular layer deposition (MLD) approach to prepare porphyrin-based covalent organic molecular networks on a 3-aminopropyl trimethoxysilane (APTMS) modified substrate surface using the urea coupling reaction between 1,4-phenylene diisocyanate (1,4-PDI) and 5,10,15,20-tetrakis-(4-aminophenyl) porphyrin (H2TAPP) at room temperature (22 ± 2 °C). Multilayer growth was investigated under different relative humidity (RH) conditions of the reaction chamber. Sequential molecular growth at low relative humidity (≤10% RH) was observed using UV–vis absorption spectroscopy and atomic force microscopy (AFM). The high-RH condition shows limited film growth. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) revealed the polyurea bond formation in sequential multilayer thin films, demonstrating that stepwise multilayer film growth was achieved using the urea coupling reaction.
This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a ...calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale.
•Ammonia from a poultry unit can be detected 2.8 km upwind.•Ammonia caused exceedance of critical levels 800 m and critical loads 2.8 km upwind.•Dune grassland species utilised ammonia as a nutrient source.•Plant biomass increased at low levels of ammonia and total nitrogen deposition.•Soil C pools are predicted to increase by 9% over 50 years due to the excess ammonia.
Ammonia from a poultry unit has upwind impacts, exceeding critical levels 800 m and critical loads 2.8 km upwind, and increasing biomass and tissue N of dune grassland species.
Lithium-ion batteries (LIBs) have nowadays become outstanding rechargeable energy storage devices with rapidly expanding fields of applications due to convenient features like high energy density, ...high power density, long life cycle and not having memory effect. Currently, the areas of LIBs are ranging from conventional consumer electronics to electric vehicles (EVs) to aerospace applications. To maintain the demand of widespread application, LIBs with certain specific features are the focus to meet the purpose-oriented requirements. High energy density is one of the prime requirements in the case of vehicular application of LIBs to address the issue of the limited driving range of EVs. The expected acceleration in the commercial growth of EVs is being impeded due to the present level of the driving range offered by the LIB pack. However, this issue can be improved by increasing the energy density of LIBs at the cell level. Because the same size of LIB pack with high energy density LIB cells will deliver a higher amount of power to extend the driving range of EVs. Elevated energy density in the cell level of LIBs can be achieved by either designing LIB cells by selecting suitable materials and combining and modifying those materials through various cell engineering techniques which is a materials-based design approach or optimizing the cell design parameters using a parameter-based design approach. In this paper, a comprehensive review of existing literature on LIB cell design to maximize the energy density with an aim of EV applications of LIBs from both materials-based and cell parameters optimization-based perspectives has been presented including the historical development of LIBs, gradual elevation in the energy density of LIBs, applications of LIBs in EVs, the decreasing trend of LIB cost, and ways of enhancing EV driving range with an outlook of promising battery technologies.
This paper provides a comprehensive review of 71 previous studies on the life cycle assessment (LCA) of nanomaterials (NMs) from 2001 to 2020 (19 years). Although various studies have been carried ...out to assess the efficiency and potential of wastes for nanotechnology, little attention has been paid to conducting a comprehensive analysis related to the environmental performance and hotspot of NMs, based on LCA methodology. Therefore, this paper highlights and discusses LCA methodology's basis (goal and scope definition, system boundary, life cycle inventory, life cycle impact assessment, and interpretation) to insights into current practices, limitations, progress, and challenges of LCA application NMs. We found that there is still a lack of comprehensive LCA study on the environmental impacts of NMs until end-of-life stages, thereby potentially supporting misleading conclusions, in most of the previous studies reviewed. For a comprehensive evaluation of LCA of NMs, we recommend that future studies should: (1) report more detailed and transparent LCI data within NMs LCA studies; (2) consider the environmental impacts and potential risks of NMs within their whole life cycle; (3) adopt a transparent and prudent characterization model; and (4) include toxicity, uncertainty, and sensitivity assessments to analyze the exposure pathways of NMs further. Future recommendations towards improvement and harmonization of methodological for future research directions were discussed and provided. This study's findings redound to future research in the field of LCA NMs specifically, considering that the release of NMs into the environment is yet to be explored due to limited understanding of the mechanisms and pathways involved.
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