Irradiation Method Research Articles

Evaluation of strategies to incorporate silver nanoparticles into electrospun microfibers for the preparation of wound dressings and their antimicrobial activity

ABSTRACT Currently, wound dressing technology is of significant interest in order to avoid undesired effects when burns or skin wounds are treated, especially their risk for microbial contamination and subsequent infection. Silver nanoparticles (AgNPs) have claimed importance as antimicrobial agents. For these reasons, a comparative study of different methods to synthesize electrospun polymeric fibers loaded with AgNPs (Ag+/PCLPVP) such as direct blending, ultraviolet irradiation, thermal treatment, and silver mirror reaction methods were done. The morphology and size of the fibers were investigated using the SEM, where the loading of the AgNPs in the fibers was measured with EDS analysis. FTIR, Raman spectroscopy, XRD, and TGA analysis were applied to measure the physicochemical properties of the fibers. DLS study allowed us to measure the size and surface charge of the obtained materials. The antimicrobial efficiency was carried out against Staphylococcus aureus and Escherichia coli bacteria for 24 h. Cytotoxicity was evaluated with the MTT assay using HFF1 cells. The results showed that the method with the best antimicrobial effect in both bacteria is the UV irradiation conducted before the electrospinning process. The UV radiation method also promotes good distribution efficiency, the physicochemical properties obtained were desirable for wound dressings, and the particle size within nanoparticle interval (~17 nm). Therefore, the most promising method for the preparation of Ag+/PCLPVPbased wound dressings was UV irradiation.

3D printed 2D range modulators preserve radiation quality on a microdosimetric scale in proton and carbon ion beams

IntroductionParticle therapy using pencil beam scanning (PBS) faces large uncertain- ties related to ranges and target motion. One possibility to improve existing mitigation strategies is a 2D range modulator (2DRM). A 2DRM offers faster irradiation times by reducing the number of layers and spots needed to create a spread-out Bragg peak. We have investigated the impact of 2DRM on microdosimetric spectra measured in proton and carbon ion beams. Materials and MethodsTwo 2DRMs were designed and 3D printed, one for.124.7 MeV protons and one for 238.6 MeV/u carbon ions. Their dosimetric validation was performed using Roos and PinPoint ionization chamber and EBT3 films. Monte Carlo simulations were done using GATE. A silicon-based solid-state microdosimeter was used to collect pulse-height spectra along three depths for two irradiation modalities, PBS and a single central beam. ResultsFor both particle types, the original pin design had to be optimized via GATE simulations. The difference between the R80 of the simulated and measured depth dose curve was 0.1 mm. The microdosimetric spectra collected with the two irradiation modalities overlap well. Their mean lineal energy values differ over all positions by 5.2 % for the proton 2DRM and 2.1 % for the carbon ion 2DRM. ConclusionRadiation quality in terms of lineal energy was independent of the irradiation method. This supports the current approach in reference dosimetry, where the residual range is chosen as a beam quality index to select stopping power ratios.

Fabrication of dialysis membrane from cotton Giza 86 cellulose di-acetate prepared using Ac2O and NiCl2 as a new catalyst

This attempt has been made to synthesize the cellulose di-acetate in a solvent-free acetylation system of cotton Giza 86 cellulose with Ac2O (200 and 300 ml) in the presence of NiCl2.6HO (1.0, 1.5 and 2.0 g) as an effectively available and new catalyst by the conventional reflux and microwave irradiation methods. This study also illustrates the preparation of a dialysis membrane made from a cellulose di-acetate–dichloromethane-methanol-polyethylene glycol (MW: 200) casting solution. The microwave irradiation method for the synthesis of cellulose di-acetate showed excellent yields and short reaction time, which is an important feature of this method. The impact of the two methods on the cellulose di-acetate formation and its used in the dialysis membrane formulations was studied. The experimental degree of substitution of the prepared cellulose di-acetate values (DS = 2.00–2.7) showed an agreement with the calculated values by FTIR and 1H-NMR analysis methods. The formation of cellulose di-acetate with percentage yields varied from 62.85 to 89.85%. The applicability of the prepared membrane in dialysis operation was evaluated in terms of urea clearance, rejection of Bovine Serum Albumin (BSA) and flux of pure water. Characterization of cellulose di-acetate was achieved through 1H-NMR, FTIR, TGA, and BET analyses. The CA-PEG blend membrane was examined by contact angle measurement, porosity, and water uptake of the membrane. The cellulose acetate membrane surface morphology was determined using SEM. It is observable that the fabricated CA-PEG blend membrane from synthesized cellulose di-acetate by using Nickel chloride as a catalyst is showing remarkable rejection of BSA and urea clearance up to 100 and 67.2%, respectively. The present work is promising and applicable in dialysis membranes.

Equivalence study of extractables from single-use biopharmaceutical manufacturing equipment after X-ray or gamma irradiation

Single-use (SU) devices and assemblies used as manufacturing equipment in the biopharmaceutical industry require comprehensive qualifications. These qualifications include the assessment of compounds released from SU devices in contact with the process fluids, and how these leachable compounds potentially influence process performance, drug product quality, and patient safety. SU suppliers need to provide comprehensive qualification data for several parameters, for both new products and product changes, such as changes in the sterilization process applied to the SU device. The introduction of X-ray irradiation as an alternative to the currently used and established gamma irradiation of SU devices represents a situation where robust data is required to demonstrate equivalency between these two radiation technologies. Here, we present the results of a comprehensive extractables study for three SU components, bags, tubing, and sterilizing grade filters, evaluated after X-ray and gamma-ray irradiation. The selected study conditions were set up to allow a direct comparison of the results from the two sterilization methods, and to allow conclusions to be made on the impact of irradiation type on the polymers and their additives. Orthogonal analytical methods are applied to identify and quantify all organic compounds present. The data package provided here supports risk assessments for application of irradiated SU equipment in biopharmaceutical manufacturing. The formation of reaction products and the fundamental chemical pathways are discussed and found to be independent of the irradiation type. The results demonstrate the equivalency of both irradiation methods for extractables from plastic components used in pharmaceutical and biopharmaceutical manufacturing.

A sonochemical synthesis of SrTiO3 supported N-doped graphene oxide as a highly efficient electrocatalyst for electrochemical reduction of a chemotherapeutic drug.

A sonochemical based green synthesis method playa powerful role in nanomaterials and composite development. In this work, we developed a perovskite type of strontium titanate via sonochemical process. SrTiO3 particles were incorporated with nitrogen doped graphene oxide through simple ultrasonic irradiation method. The SrTiO3/NGO was characterized by various analytical methods. The nanocomposite of SrTiO3/NGO was modified with laser-induced graphene electrode (LIGE). The SrTiO3/NGO/LIGE was applied for electrochemical sensor towards chemotherapeutic drug detection (nilutamide). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques have been used to examine the electrochemical performance of nilutamide (anti-cancer drug). DPV was found to be more sensitive and found to exhibit a sensitivity 8.627 µA µM-1 cm-2 for SrTiO3/NGO/LIGE with a wide linear range (0.02-892µM) and low Limit of detection (LOD: 1.16µM). SrTiO3/NGO/LIGE has been examined for the detection of nilutamide in blood serum and urine samples and obtained a good recovery in the range of 97.2-99.72%. The enhanced stability and selectivity and practical application results indicates the suitability of SrTiO3/NGO/LIGE towards the detection of nilutamide drug in pharmaceutical industries.

Thermal Observation of Zr (IV) and UO2 (VI) Complexes Derived from Thiazole Schiff Base

The innovative newly thiazole Schiff base have been synthesized 2-hydroxy-5-chloro acetophenone and 4-(p-hydroxyphenyl)-2-aminothiazole by microwave irradiation method. The metal complexes were obtained as a result of interaction of Schiff base ligand and metal ions Zr (IV) and UO2(VI). The complexes have been characterized on the basis of elemental analysis, infrared, molar conductance, magnetic Susceptibilities, and theromogravimetric analysis. The kinetic analysis of the thermogravimetric data was performed by using Broido, Horowitz-Metzger and Freeman-Carroll method, which confirm first order kinetics and kinetic compensation effect.

Efficient Oxygen Doping of Graphitic Carbon Nitride by Green Microwave Irradiation for High-Performance Supercapacitor Electrode Material

A highly efficient microwave irradiation method was employed for doping oxygen into the g-C3N4 framework using H2O2, which entailed 10 min compared to energy- and time-intensive calcination and hydrothermal methods. HR-XPS revealed that O doping preferentially occurred through replacement of two coordinated N atoms of the triazine units. The effects of the ensuing electronic structure modulation were investigated with electrochemical tests where the metal-free catalyst displayed a specific capacitance of 262.5 F/g at a 1 A/g current density and a satisfactory capacitance retention of 73.17% at 6 A/g after 2000 cycles, which is comparable to those of various metals containing g-C3N4-based catalysts. The designed asymmetric supercapacitor device revealed a specific energy of 36.45 Wh/kg at a specific power of 2.5 kW/kg. The microwave-irradiated O-doped g-C3N4 showed an 8-fold increase in specific capacitance compared with bulk g-C3N4 in both CV and GCD analyses. The improved surface structure and O content enhanced the electrode–electrolyte contact area, thus making ion transfer highly efficient for EDLCs. These results also opened the potential of microwave-synthesized O-doped g-C3N4 as a base material for designing binary and ternary electrode materials.

Effect of Er: YAG laser irradiation with additional low energy on resin-dentin bonding and morphology of bonded interface

ObjectivesTo examine the micro tensile bond strength (μTBS) and the resin-dentin interface on a laser-irradiated dentin surface using two different irradiation methods, with or without additional low-energy irradiation. MethodsThe flat bovine dentin surface was divided into three groups: i). control group (C group, no irradiation), ii) 80 mJ/pulse Er: YAG laser group (80 group), iii) 80 + 30 mJ/pulse Er: YAG laser group (80 + 30 group, with an additional 30 mJ/pulse). After the roughness of the dentin surface was recorded, Clearfil SE Bond 2 or Clearfil Universal Bond Quick (Kuraray Noritake Dental Inc., Tokyo, Japan) was applied. After the μTBS testing, the failure mode was observed. The bonded interface was assessed using Rhodamine-dye incorporated adhesives and observed by optical coherence tomography. ResultsThe dentin surface showed opened dentinal tubules without a smear layer after irradiation. For both adhesives, the μTBS was significantly higher in 80 + 30 group than in the 80 group (p < 0.05). In the 80 group, the thickness of the adhesive layer was not uniform, and the dentin surface was occasionally in direct contact with the composite resin. The failure mode images showed that most of the fractures in the 80 group were at the sub-surface of irradiated dentin. The adhesive layers of the 80 + 30 groups were homogeneous. ConclusionsThe dentin surface was rough and irregular by 80 mJ irradiation, which might result in an inadequate resin-dentin interface and the weak μTBS. The bonded integrity was mitigated by additional irradiation.

Stabilization of Functional DNA Structures with Mild Photochemical Methods.

A significant barrier to biological applications of DNA structures is their instability to nucleases. UV-mediated thymine dimerization can crosslink and stabilize DNA nanostructures, but its effect on DNA strand hybridization fidelity and function is unclear. In this work, we first compare a number of methods for DNA irradiation with different wavelengths of light and different photosensitizers. We demonstrate that all approaches can achieve nuclease protection; however, the levels of DNA off-target crosslinking and damage vary. We then describe mild irradiation conditions intended to safeguard DNA against nuclease degradation. We demonstrate up to 25× increase in serum stability while minimizing off-target damage and maintaining functions such as hybridization efficiency, gene silencing, aptamer binding, and DNA nanostructure formation. Our methodology requires no complex instruments beyond a UV light source and no synthetic modification of the DNA itself, allowing for applications in numerous areas of nucleic acid therapy and nanotechnology.

Ambient Electrosynthesis of Urea with Nitrate and Carbon Dioxide over Iron‐Based Dual‐Sites

AbstractThe development of efficient electrocatalysts to generate key *NH2 and *CO intermediates is crucial for ambient urea electrosynthesis with nitrate (NO3−) and carbon dioxide (CO2). Here we report a liquid‐phase laser irradiation method to fabricate symbiotic graphitic carbon encapsulated amorphous iron and iron oxide nanoparticles on carbon nanotubes (Fe(a)@C‐Fe3O4/CNTs). Fe(a)@C‐Fe3O4/CNTs exhibits superior electrocatalytic activity toward urea synthesis using NO3− and CO2, affording a urea yield of 1341.3±112.6 μg h−1 mgcat−1 and a faradic efficiency of 16.5±6.1 % at ambient conditions. Both experimental and theoretical results indicate that the formed Fe(a)@C and Fe3O4 on CNTs provide dual active sites for the adsorption and activation of NO3− and CO2, thus generating key *NH2 and *CO intermediates with lower energy barriers for urea formation. This work would be helpful for design and development of high‐efficiency dual‐site electrocatalysts for ambient urea synthesis.

Ambient Electrosynthesis of Urea with Nitrate and Carbon Dioxide over Iron-Based Dual-Sites.

The development of efficient electrocatalysts to generate key *NH2 and *CO intermediates is crucial for ambient urea electrosynthesis with nitrate (NO3 - ) and carbon dioxide (CO2 ). Here we report a liquid-phase laser irradiation method to fabricate symbiotic graphitic carbon encapsulated amorphous iron and iron oxide nanoparticles on carbon nanotubes (Fe(a)@C-Fe3 O4 /CNTs). Fe(a)@C-Fe3 O4 /CNTs exhibits superior electrocatalytic activity toward urea synthesis using NO3 - and CO2 , affording a urea yield of 1341.3±112.6 μg h-1 mgcat -1 and a faradic efficiency of 16.5±6.1 % at ambient conditions. Both experimental and theoretical results indicate that the formed Fe(a)@C and Fe3 O4 on CNTs provide dual active sites for the adsorption and activation of NO3 - and CO2 , thus generating key *NH2 and *CO intermediates with lower energy barriers for urea formation. This work would be helpful for design and development of high-efficiency dual-site electrocatalysts for ambient urea synthesis.

The Effectiveness of Ultraviolet Based Methods Versus Other Novel Methods in the Disinfection of Escherichia Coli Found in Drinking Water : A Systematic Review

Summary : A total of 19 studies with different disinfection methods, primarily grouped into Ultraviolet (UV) only, combination and Non-UV, are selected to find the effectivity of UV disinfection compared to other novel disinfection methods in the inactivation of Escherichia coli (E. coli) present in drinking water. All methods chosen produce significant results regarding E. coli inactivation. Background : Drinking water is an essential part of life that everyone needs. Many drinking water sources are contaminated with E. coli. There are numerous disinfection methods, including UV irradiation. Author wants to find out which disinfection modality, UV irradiation or other methods, is more effective at inactivation E. coli found in drinking water. Objectives : To find the effectivity of UV disinfection compared to other novel disinfection methods in the inactivation of Escherichia coli present in drinking water. Method : Literatures from PubMed, Science Direct and Google Scholar published in 1990-2020 were searched using MeSH terms and the Boolean Logic ‘AND’, with the key words included being ‘Disinfection’, ‘Ultraviolet Rays’, ‘Drinking Water’ and ‘Escherichia coli’. Then these literatures were filtered according to inclusion and exclusion criteria. Key data extracted from each finding included details of study design and duration of observation, type of water sample used, movement of water sample, water sample volume, comparison group, method of disinfection, source of disinfection, dose of disinfection, duration of disinfection, enumeration method of counting E. coli , type of E. coli, initial concentration of E. coli and outcome of concentration of E. coli after disinfection. Results : 19 studies were included in this systematic review. All studies shows significant decrease in E.coli concentration after disinfection. Conclusion : UV treatment could significantly reduce E. coli found in drinking water. Keywords : Drinking water, Escherichia coli, Ultraviolet, UV, Disinfection

Binary Graft of Poly(acrylic acid) and Poly(vinyl pyrrolidone) onto PDMS Films for Load and Release of Ciprofloxacin.

Polymers are versatile compounds which physical and chemical properties can be taken advantage of in wide applications. Particularly, in the biomedical field, polydimethylsiloxane (PDMS) is one of the most used for its high biocompatibility, easy manipulation, thermal, and chemical stability. Nonetheless, its hydrophobic nature makes it susceptible to bacterial pollution, which represents a disadvantage in this field. A potential solution to this is through the graft of stimuli-sensitive polymers that, besides providing hydrophilicity, allow the creation of a drug delivery system. In this research, PDMS was grafted with acrylic acid (AAc) and vinyl pyrrolidone (VP) in two steps using gamma radiation. The resulting material was analyzed by several characterization techniques such as infrared spectroscopy (FTIR), swelling, contact angle, critical pH, and thermogravimetric analysis (TGA), demonstrating the presence of both polymers onto PDMS films and showing hydrophilic and pH-response properties. Among the performed methods to graft, the loading and release of ciprofloxacin were successful in those samples obtained by direct irradiation method. Furthermore, the antimicrobial assays showed zones of inhibition for microorganisms such as Staphylococcus aureus and Escherichia coli.

Novel solid target and irradiation methods for theranostic radioisotope production at the Bern medical cyclotron

The production of medical radioisotopes for theranostics is essential for the development of personalized nuclear medicine. Among them, radiometals can be used to label proteins and peptides and their supply in quantity and quality suitable for clinical applications represents a scientific challenge. A research program is ongoing at the Bern medical cyclotron, where an IBA Cyclone 18/18 HC is in operation. The cyclotron provides 18 MeV proton beams up to 150 μA and is equipped with a Solid Target Station (STS) and a 6 m Beam Transport Line (BTL), ending in a separate bunker with independent access. A novel magnetic target coin was realized to bombard isotope-enriched materials in the form of compressed powders, together with a compact focalization system to enhance the irradiation procedure. For an optimized production yield with the required radionuclidic purity, novel methods were developed to precisely measure the extracted beam energy and the involved reaction cross sections. In particular, a target station was realized to measure nuclear cross sections using materials in the form of powder deposited on an aluminium disc by sedimentation, bombarded by a monitored flat beam.

Evaluation of Physicochemical Parameters of Biosorbents Produced from Groundnut Hull Using Microwave Assisted Irradiation Method

Samples of ground nut hull were converted to biosorbents using microwave assisted method [groundnut hull treated with hydrogen peroxide (HP-GH), groundnut hull treated with distilled water (W-GH) and raw groundnut hull (R-GH)]. The biosorbents were further characterized using physicochemical procedures (pH dependence, bulk density, surface area, ash content, and volatile matter, moisture content). The results show that HP-GH has pH = 8.9, W-GH pH = 8.4 and R-GH pH = 8.5 which is an indication that all the biosorbents have the appropriate pH values for the uptake of cationic species within aqueous systems. Surface area analysis revealed that HP-GH has the largest surface area (74.20 m2·g-1) while W-GH and R-GH have surface area values of 29.40 m2·g-1 and 21.40 m2·g-1 respectively. This suggests that modification of raw groundnut hull biomass with hydrogen peroxide possibly instigated delignification of the biomass which resulted in increased surface area for HP-GH. Results from Bulk density analysis also confirm the data obtained from surface area analysis. Accordingly, R-GH displayed the highest bulk density followed by W-GH with HP-GH showing the least bulk density. The variation in pH values among the biomass used in this study may be explained by the variation in their ash content as well because pH and ash content are positively correlated. Hence, HP-GH with a pH = 8.9 has high ash content (117.31%), W-GH with pH = 8.4 has 97.93% ash content and R-GH with pH = 8.5 has 94.26% ash content. Results from moisture content analysis show that HP-GH (99.95%), W-GH (99.97%) and R-GH (99.89%) may necessitate exposure of the biosorbents to moderate heat before use. The results obtained from this study suggest that modification of ground nut hull with either distilled water or Hydrogen peroxide by means of microwave irradiation improves physicochemical properties which may perhaps increase the adsorption capacity of the biomass.

A hydrogel gripper enabling fine movement based on spatiotemporal mineralization.

Fine tailoring of the subtle movements of a hydrogel actuator through simple methods has widespread application prospects in wearable electronics, bionic robots and biomedical engineering. However, to the best of our knowledge, this challenge is not yet completed. Inspired by the diffusion-reaction process in nature, a hydrogel gripper with the capability of fine movement was successfully prepared based on the spatiotemporal fabrication of the polypyrrole (PPY) pattern in a poly (N-isopropylacrylamide) (PNIPAM) hydrogel. The hydrogel was given gradient porous structures using a one-step UV irradiation method. Moreover, photothermal PPY patterns on the hydrogel were obtained through spatiotemporal mineralization of ferric hydroxide followed by the polymerization of pyrrole in a controllable manner. Taking advantage of the unique structures, the hydrogel gripper can not only achieve reversible grasping-releasing of substrates with the tuning of temperature (similar to that of hands), but also generate delicate movement under the irradiation of light (resembling that of finger joints). The strategy reported here is easily accessible and there is no need for sophisticated templates, therefore making it superior to other existing methods. We believe this work will provide references for the design and application of more advanced soft actuators.

Structural Analysis of Calcium Oxide Derived from Waste Egg’s Shells and their Application for Knoevenagel Condensation Reactions

The present study demonstrates the simple and easy synthesis of calcium oxide (CaO) from waste egg’s shells. Fine egg’s shells powder were calcinated at 500, 700 and 800 ºC. The structural and morphological evaluation of calcium oxide derived from waste egg’s shell were examined by using XRD, FT-IR, SEM, EDS and TEM techniques. The sintered calcium oxide was used as heterogeneous catalyst for the synthesis of 5-arylidene malononitrile and 5-arylidene barbituric acid derivatives by the condensation of various aromatic aldehyde and active methylene compounds via Knoevenagel condensations reaction under ultrasound irradiation method. The reaction completed within a very short reaction time with high yields of product. The present method describes easy synthesis of calcium oxide catalyst from the waste egg’s shells, short reaction times, simple product isolation, excellent yield and reusability of the catalyst.

Effects of 60Co γ-ray irradiation of thin-layer molybdenum disulfide for the hydrogen evolution reaction

A γ-ray irradiation method is expected to achieve the development of efficient, inexpensive, mass-produced, and chemically stable MoS2 catalysts.

First report on larvicidal potential of zinc sulfide aqua nanoparticles against Aedes aegypti (Linnaeus).

Mosquitoes are considered to be the deadliest arthropod-vectors, which cause millions of human deaths globally. Presently, nanotechnology in the field of insect pest management is being explored. The current study deals with the synthesis of zinc sulfide nanoparticles (ZnS NPs) in aqueous medium and their larvicidal efficacy against Ae. aegypti. Aqueous zinc sulfide nanoparticles were synthesized by mixing equal quantities of zinc acetate and zinc sulfide solutions by using sonochemical irradiation method. The synthesized NPs were characterized by Transmission Electron Microscopy (TEM). Larvicidal activity was performed according to WHO protocol and toxicity values were calculated by log-probit technique using POLO software. The morphological alterations between treated and control larvae were observed and compared. TEM studies revealed the average particle size of synthesized nanoparticles to be 19.65 ± 1.08 nm with distorted spherical shape. The mosquito-larvicidal efficacy of ZnS NPs against Ae. aegypti showed maximum lethal effects with the LC50 and LC90 values of 4.49 and 15.58 ppm respectively. The morphological analysis of the mosquito larvae treated with ZnS NPs revealed shrunken and darkened body. This study suggests that synthesized zinc sulfide aqua nanoparticles have good potential larvicidal properties making them best candidate for Aedes aegypti control.

Surface Smoothing for Metal Parts Fabricated by Additive Manufacturing Using Large-area EB Irradiation Method

Surface Smoothing for Metal Parts Fabricated by Additive Manufacturing Using Large-area EB Irradiation Method