Plate Method Research Articles

Exploring comparative analysis of antibiotic resistance patterns in E.coli bacterial strains through the agar plate method

Abstract Introduction Antibiotic effectiveness varies across classes and bacteria, complicating the fight against infections. Utilising E. coli as a model organism offers insights into the microbial response to antibiotics. The agar plate method is crucial for visualising and assessing antibiotic resistance efficacy1. The looming threat of antibiotic resistance, with a potential death toll of 10 million by 2050, emphasises the urgency2. Investigating E. coli's role in gut health and its interaction with antibiotics via agar plate assays informs the selective use of broad-spectrum and narrow-spectrum antibiotics, vital for medical and agricultural applications3. Aim This study aims to explore the differential efficacy of broad-spectrum and narrow-spectrum antibiotics, including ampicillin, chloramphenicol, cefoxitin, and erythromycin, against E. coli using the agar plate method. The study aims to evaluate the effects of different antibiotics on E. coli to identify patterns of resistance and susceptibility, providing insights into the bacterial response to these drugs. Methods To maintain aseptic conditions, all equipment was sterilised, and a sterile workspace was established, as illustrated. The agar plates were carefully labelled with the specific bacterial strains and antibiotics slated for evaluation. Employing sterile techniques, the E. coli strains were swabbed onto these agar plates to ensure an even distribution. Antibiotic discs were then methodically placed onto the agar, spaced appropriately to prevent overlap, and gently pressed to ensure contact with the medium. These plates were subsequently incubated at 37°C for 24-48 hours, allowing for bacterial growth and antibiotic diffusion. Post-incubation, the diameters of the inhibition zones around each antibiotic disc were meticulously measured. Following the experimental procedures, biohazard materials were disposed of in accordance with safety protocols, and equipment was re-sterilised. To uphold the experiment’s validity and reliability, it was repeated over four weeks, with the average results compiled and analysed. Results This study evaluates the antibacterial effectiveness of four antibiotics over four weeks, measuring the area of inhibition against E. coli. Ampicillin's inhibition varied significantly, with a peak of 2358.58 mm² in Week 3 after a drop to 1468.46 mm² in Week 2. Chloramphenicol also showed variability, peaking at 897.27 mm² in Week 3. Cefoxitin displayed a consistent increase in effectiveness, with an inhibition area of 2317.44 mm² in Week 2. Erythromycin showed no inhibitory effect throughout the study. The data emphasises the dynamic bacterial response to these treatments. Discussion or Conclusions This study provides valuable insights into the relationship between antibiotic use and bacterial resistance in E. coli strains, utilising the agar plate method to assess antibiotic effectiveness and predict future resistance trends. By analysing inhibition zone patterns over time, the study identifies emerging resistance, suggesting this method’s utility in forecasting bacterial evolution. However, the approach is limited by its focus on in vitro conditions, which may not fully capture in vivo complexities, and it does not consider genetic mutations or environmental influences. These limitations highlight the need for more comprehensive research. The study advocates for integrated global strategies, combining judicious antibiotic use with novel antimicrobial developments.

Characterization of phage HZY2308 against Acinetobacter baumannii and identification of phage-resistant bacteria

Background Acinetobacter baumannii (AB) is a notable cause of hospital-acquired infections, with carbapenem-resistant Acinetobacter baumannii (CRAB) classified as a high-priority critical pathogen. Bacteriophage therapy is emerging as a promising alternative to combat drug-resistant bacterial infections. In this study, a lytic phage, HZY2308, was isolated from hospital sewage, and the biological properties, biosafety and anti-biofilm properties of phage HZY2308 were characterized and identified. Moreover, the antibacterial effect of phage HZY2308 in combination with antibiotics was investigated, and the apparent characteristics of phage-resistant strain AB48-R were demonstrated, which provided data support for further studies to elucidate the mechanism of generating phage resistance.MethodsPhage HZY2308 was isolated by double agar plate method using clinical strain AB48 as the host bacterium. The morphology of phage HZY2308 was identified by transmission electron microscopy (TEM), and biological characteristics of phage HZY2308 were identified by host range, the efficiency of plating (EOP), sensitivity to temperature, pH, and chloroform, one-step growth curve, the optimal multiplicity of infection (MOI), and detection of endotoxin and cytotoxicity. Besides, the complete genome map of HZY2308 was constructed using CGview, and the phylogenetic tree of HZY2308 was constructed with MEGA. Additionally, the full genomic sequence of phage HZY2308 and the selected phage were compared using Easyfig. Checkerboard test of phage HZY2308 in combination with tigecycline (TGC) was performed to investigate their synergistic effect and bactericidal kinetics. The effect of HZY2308 on biofilm was investigated by semi-quantitative staining of biofilm with crystal violet, determination of bacterial activity in biofilm by 2,3-Bis (2-methoxy-4-nitro-5-sulfophenyl) -2 H-tetrazolium-5-carboxanilide (XTT) assay and observation of biofilm structure by fluorescence microscopy. Finally, Phage-resistant bacteria AB48-R were characterized by colony-forming capacity, morphology, growth curves, adsorption efficiency, and antibiotic susceptibility assays.ResultsA lytic phage, HZY2308, was isolated from hospital sewage, which exhibited advantageous traits such as a brief incubation period, large burst size, and robust stability. Safety assessments conducted at both genetic and cellular levels also have yielded positive outcomes. Besides, phage HZY2308 effectively inhibited AB biofilm formation and disrupted established biofilm structures. Furthermore, a synergistic antibacterial effect was noted when phage HZY2308 was combined with tigecycline. Interestingly, the phage-resistant strain, AB48-R was screened through natural selection. Compared to the wild strain AB48, the adsorption efficiency of the phage to AB48-R diminished. However, AB48-R’s sensitivity to antibiotics such as cefepime, gentamicin, amikacin, and tobramycin increased, indicating an evolutionary trade-off.ConclusionsPhage HZY2308 shows strong antimicrobial potential, especially in combination with tigecycline, and the phage-resistant strain exhibits increased antibiotic sensitivity.

Thermal Conductivity, Density and Calorific Value of Sargassum Fluitans and Sargassum Natans Species

In this study, we obtained the values of the thermodynamic properties of sargassum that includes S. fluitans and S. natans species, which are the ones that most arrive at the coasts of the Mexican Caribbean. The sargassum samples, collected at the coast, were dried in a direct type of solar dryer and their final relative humidity was 15% dry base. Two physical models were designed to construct biscuits of 0.0127 m in diameter and 0.0063 m in length, which were used to obtain the density and calorific value and those used for thermal conductivity, were 0.069 m in diameter and 0.008 m thick. The density resulted in 660.62 𝑘𝑔/𝑚3 . To determine the calorific value, a commercial calorimetric pump was used, and the value obtained was 17,950 𝑘𝐽/𝑘𝑔. For thermal conductivity, a device that employs the hot plate and guard method was designed and built and its value was 0.346 𝑊/𝑚°𝐶. These values indicate that it is possible to use dehydrated sargassum to produce energy, which has approximately a value of 75% of that obtained for sugar cane bagasse. With these three values and using the thermal diffusivity definition equation, this last parameter was calculated in 2.917 × 10−11 𝑚2 /𝑠.

One-step electrodeposition of reduced graphene oxide-amorphous carbon composite coatings for proton exchange membrane fuel cell bipolar plates

In this paper, a convenient electrodeposition method is proposed to directly fabricate a reduced graphene oxide-amorphous carbon composite coating (rGO-ACC) on a 316L stainless steel substrate. The rGO-ACC coating is achieved through a one-step reduction by utilizing a choline chloride-ethylene glycol deep eutectic solvent (DES) with the dispersion of graphene oxide. The analysis results from SEM, Raman and XPS reveal that the obtained rGO-ACC coating, with layered wrinkle morphology, uniformly covers and covalently bonds to 316L stainless steel substrate. Potentiodynamic and potentiostatic polarization tests showed that the corrosion current densities of rGO-ACC coated 316L stainless steel were of the order of 10-7 A cm−2 in simulated proton exchange membrane fuel cells (PEMFC) working environment, indicating a significant improvement of corrosion resistance of 316L and an excellent electrochemical stability. Meanwhile, compared with the naked 316L steel, the interfacial contact resistance (ICR) of the coated stainless steel is significantly reduced due to the outstanding electrical conductivity of the coated rGO. The results manifested that deposited rGO-ACC on steel surface may be a highly promising modification method for PEMFC metal bipolar plates.

Maggot kinase: A novel and cost-effective fibrinolytic enzyme from maggots

Maggot kinase, a novel fibrinolytic enzyme source, has been isolated from fly maggots and comprehensively characterized. Using CM-52 ion exchange chromatography and affinity chromatography, we obtained a highly purified and active form of the enzyme. In particular, the fibrinolytic activity of maggot kinase, evaluated using the fibrin plate method, was found to be 8.98 ± 0.08 × 105 U/mg, demonstrating significant efficacy. Further structural analysis using mass spectrometry revealed that maggot kinase consists of a primary sequence of 226 amino acid residues with a molecular weight of 22.91 kDa. In vitro thrombolytic assays demonstrated the enzyme's remarkable ability to degrade the essential fibrinogen subunits (α, β, and γ), thereby facilitating clot lysis. Notably, our studies in a mouse model underscored the significant in vivo thrombolytic activity of maggot kinase, demonstrating its potential to inhibit thrombosis. The finding is particularly significant considering the widespread use of fly maggots in agriculture and animal husbandry due to their rapid growth cycle and minimal nutritional requirements. Our research highlights the untapped potential of fly maggots as a source for maggot kinase development for antithrombotic drug and functional food applications.

Antibacterial and anti-biofilm efficacy of selenium nanoparticles against Pseudomonas aeruginosa: Characterization and in vitro analysis

Pseudomonas aeruginosa (P. aeruginosa), a Gram-negative opportunistic pathogen, poses significant treatment challenges due to its antibiotic resistance and biofilm formation. This study investigates the anti-bacterial and anti-biofilm activities of chemically synthesized selenium nanoparticles (SeNPs) against P. aeruginosa. SeNPs were synthesized using ascorbic acid as a reducing agent and characterized. Biofilm formation was quantified using a modified microtiter plate method, and the anti-biofilm efficacy of SeNPs was evaluated using confocal microscopy and SEM. The P.aeruginosa isolates exhibited high resistance to piperacillin-tazobactam (60%) and ceftazidime (59%). SeNPs demonstrated a round shape with a diameter of 15-18 nm. UV-Vis spectra showed a peak at 275 nm, and XRD analysis revealed crystalline peaks corresponding to selenium. The FTIR spectra confirmed the presence of various functional groups. SeNPs significantly reduced biofilm formation in a dose-dependent manner, with MIC50 and MIC90 values of 60 μg/mL and 80 μg/mL, respectively. Confocal microscopy and SEM analysis showed a notable decrease in biofilm thickness and bacterial adherence post-SeNPs treatment. These findings suggest that SeNPs could be a promising alternative or adjunctive treatment option for combating antibiotic-resistant P. aeruginosa infections. Further research is warranted to explore the clinical applications of SeNPs in treating biofilm-associated infections.

Recycled industrial waste silicon steel as high-performance electrode for oxygen evolution reaction using electroless plating surface modification

Exploring the large-area, cost-effective, and high-performance electrocatalyticoxygen evolution reaction (OER) electrode for water splitting is of great significance. Inspiring from the ‘waste to resource’ toward the circular economy, herein, the waste silicon steels (SS) were transformed into high-performance CoxFe3-xP/SS OER electrode through a facile electroless plating method. The plating layer of CoxFe3-xP not only endows the CoxFe3-xP/SS with outstanding electrocatalytic OER activity but also improves the corrosion resistance and stability of CoxFe3-xP/SS. The obtained Co2Fe1P/SS electrode exhibits the lowest overpotential of 244 mV at a current density of 10 mA/cm2 in 1 M KOH with a low Tafel slope of 48.7 mV/dec. Even at high current densities and in 6 M KOH and alkaline seawater (seawater + 1 M KOH), the Co2Fe1P/SS electrode also shows relatively low overpotentials, as well as high long-term durability. Specially, a large-area Co2Fe1P/SS OER electrode(40 × 40 cm2)was successfully prepared via the electroless plating approach. Toward the CoxFe3-xP/SS, the bimetallic Co-Fe synergies and phosphating effect promote the exposure of active sites and charge transfer. In addition, generated M(OH)x/MOOH (M = Co or Fe) species during OER activation could synergize with CoxFe3-xP and contribute excellent catalytic activity and stability.

Biofilm formation and antibiogram profile of bacteria from infected wounds in a general hospital in southern Ethiopia

Biofilm-producing bacteria associated with wound infections exhibit exceptional drug resistance, leading to an escalation in morbidity, worse clinical outcomes (including delay in the healing process), and an increase in health care cost, burdening the whole system. This study is an attempt to estimate the prevalence and the relationship between the biofilm-forming capacity and multi-drug resistance of wound bacterial isolates. The findings intended to help clinicians, healthcare providers and program planners and to formulate an evidence-based decision-making process, especially in resource-limited healthcare settings. This study was done to assess the prevalence of bacterial infections in wounds and the antibiogram and biofilm-forming capacity of those bacteria in patients with clinical signs and symptoms, attending a General Hospital in southern Ethiopia. A cross-sectional study was performed in Arba Minch General Hospital from June to November 2021. The study participants comprised 201 patients with clinically infected wounds. Demographic and clinical data were gathered via a structured questionnaire. Specimens from wounds were taken from each participant and inoculated onto a series of culture media, namely MacConkey agar, mannitol salt agar, and blood agar, and different species were identified using a number of biochemical tests. Antimicrobial susceptibility tests were performed by means of the Kirby-Bauer disc diffusion technique following the guidelines of the Clinical and Laboratory Standards Institute. A micro-titer plate method was employed to detect the extent of biofilm formation. Bivariable and multivariable logistic regression models were applied to analyse the association between dependent and independent variables, and P values ≤ 0.05 were considered as statistically significant. Data analyses were done with Statistical Package for the Social Sciences version 25. Out of the 201 clinically infected wounds, 165 were found culture-positive with an overall prevalence of 82% (95% CI: 75.9–86.9). In total, 188 bacteria were recovered; 53.1% of them were Gram-positive cocci. The often-isolated bacterial species were Staphylococcus aureus, 38.3% (n = 72), and Pseudomonas aeruginosa, 16.4% (n = 31). The Gram-positive isolates showed considerable resistance against penicillin, 70%, and somewhat strong resistance against tetracycline, 57.7%. Gram-negative isolates showed severe resistance to ampicillin, 80.68%. The overall multi-drug resistance (MDR) among isolates was 48.4%. Extended beta-lactamase (ESBL)-producing Gram-negatives and methicillin-resistant Staphylococcus aureus (MRSA) accounted for 49 and 41.67%, respectively; 62.2% of the isolates were biofilm formers and were correlated statistically with MDR, ESBL producers, and MRSA (P < 0.005). The extent of biofilm formation and the prevalence of MDR bacteria associated with infected wounds hint at a public health threat that needs immediate attention. Thus, a more balanced and comprehensive wound management approach and antimicrobial stewardship program are essential in the study setting.

Al2O3 Nanoparticles Infiltered in the Fifth-Generation Adhesive to Carious Dentin. A SEM, EDX, μTBS, and FTIR Assessment

Aluminum trioxide (Al2O3) nanoparticles (NPs) loaded in a fifth-generation adhesive to caries-affected dentin. Molars with occlusal caries were selected. Specimens underwent acid etching and were categorized into 4 groups based on the concentration of Al2O3 NPs in the fifth-generation adhesive. Group 1: 0% Al2O3 NPs, Group 2: 2% Al2O3 NPs, Group 3: 5% Al2O3 NPs and Group 4: 10% Al2O3 NPs. Surface characterization of Al2O3 NPs was assessed via SEM, elemental distribution of particles in Al2O3 was evaluated via EDX, DC was assessed via FTIR, and antimicrobial efficacy was evaluated through the pour plate method. Teeth underwent μTBS testing using the universal testing machine. The Kruskal-Wallis test was used to assess the difference in survival rates of S. mutans. The means of different groups were compared using ANOVA and Tukey’s posthoc test to ascertain significant differences. The highest DC was observed in unmodified adhesive. The lowest DC was displayed in group 4. The highest μTBS scores were observed in group 3 samples. The lowest μTBS was observed in group 1 samples. The most effective group against S. mutans was 4. The ER adhesive loaded with 2 wt% and 5 wt% Al2O3 NPs exhibited superior μTBS and antibacterial effectiveness. The addition of Al2O3 to the adhesive resulted in a reduction in the degree of conversion.

Study of some physicochemical and bacteriological characteristics of drinking water in three selected rural communities in Wamba, Nasarawa State, Nigeria.

Access to safe drinking water remains a challenge in rural Nigeria. This study was carried out to determine physicochemical and bacteriological characteristics of drinking water in three rural communities in Wamba, Nasarawa State. A cross-sectional survey was conducted, 5 water samples were in respective cases collected from stream, well and borehole sources. Standard techniques were used for physicochemical analysis. Total viable counts, Total Staphylococcal counts, Total coliforms &amp; Feacal coliforms in the samples were obtained using pour plate method, growth on Mannitol salt agar, growth on MacConkey agar and Eosin Methylene Blue agar respectively. Stream Water had higher values for physicochemical parameters. Stream water exhibited the highest bacterial counts, followed by well and borehole water. The Bacteria isolated were Escherichia coli, Staphylococcus aureus, Pseudomonas spp, Klebsiella spp, Proteus spp and Salmonella spp. The acid lability attributes of the isolates were determined using Nutrient Agar buffered with (4-(2- Hydroxyethyl)-1- piperazineethanesulfonic acid) and Lipase activity was assessed using Trypticase soy agar supplemented with 1% Tween 80. Statistical analysis was performed using SPSS-PC statistical package, with a p-value of &lt; 0.05 it was considered statistically significant. These findings indicate contamination of drinking water sources, posing health risk to consumers and it shows the need for water treatment, monitoring &amp; public health education in rural communities.

Antibiotic Resistance, Biofilm Formation, and Identification of FimH and FimA Adhesion Genes in Uropathogenic Escherichia Coli (UPEC) Isolated from Patients in Baghdad Province

Urinary tract infections (UTIs) are one of the most common infectious disorders worldwide. The most frequent cause of UTIs is uropathogenic Escherichia coli (UPEC). The current study is designed to assess the resistance of antibiotics, the formation of biofilm, and the detection of adhesion genes in E. coli isolated from patients with UTIs. A hundred and fifty samples were collected from patients with confirmed UTIs in Baghdad province during the period of October 2022 to February 2023. Isolation and identification of E. coli were performed using cultural characteristics, gram staining, and biochemical examination, and the results indicated that 52 (35%) isolates were identified as E. coli. Eleven antibiotic discs were utilized to estimate the sensitivity of E. coli isolates. 98% of isolates were resistant to ampicillin, followed by 75.5% of isolates resistant to both trimethoprim/sulfamethoxazole and fosfomycin, followed by 73.5, 71.4, 67.3, 53.1, and 6.1% of isolates resistant to imipenem, ceftazidime, nitrofurantoin, cefepime, and amikacin. All isolates were sensitive to piperacillin-tazobactam, ciprofloxacin, and aztreonam at 100%, 100%, and 98%, respectively. The microtiter plate method was utilized to estimate the ability of E. coli to form biofilm. The majority of isolates (69.2%; n = 36) were moderate biofilm producers, while 19.2% (n = 10) and 11.5% (n = 6) of isolates were strong and weak biofilm producers, respectively. Polymerase Chain Reactions (PCR) were applied to determine the gene expression level of adhesion genes (fimH and fimA genes). Forty isolates harbored both fimH and fimA genes.

THE PREVALENCE OF (OMPA, CSUE) GENES AMONG BIOFILM PRODUCER ACINETOBACTER BAUMANNII ISOLATES

Acinetobacter baumannii is a significant public health problem because it is capable of forming biofilms that may be responsible for the survival of this pathogen in the hospital environment. The aim of this study is to determine the role of (OmpA, CsuE) genes in biofilm production among A. baumannii isolates. A total of 100 clinical isolates of bacteria were collected from a different sources. All isolates were identified by biochemical test, specific selective media (CHROMagar) and polymerase chain reaction by detection presence of (blaOXA51) gene. only 60 isolates were diagnosed as A. baumannii, and to determine the biofilm production capacity two different methods were used Congo red agar method(CRA) and Microtiter plate method (MTP). MTP method result showed 85% of isolates were able to form biofilms, on the other hand, 33.33% of isolates had a biofilm production ability by showing bright black colonies on CRA. Conventional PCR was used to detect the presence of (OmpA, CsuE) genes and the result showed the prevalence of both genes in all isolates were 97%(58/60). It also shows a strong correlation between the presence of these genes and biofilm formation.

A flexible porous polyimide/copper composite film toward high-mass-loading anodes in lithium-ion batteries

Conventional metal foil current collectors are essential for electronic conduction in lithium-ion batteries, but the planar structure limits the fast transporting of electron and the power density. Herein, a light, conductive, self-extinguishing, and flexible porous polyimide/copper composite film (PIF/Cu) derived from a polyimide foam was fabricated via hot pressing and electroless plating methods. The honeycomb structure was illustrated in PIF/Cu under a 3D X-ray tomography microscope, revealing the successful construction of a 3D conductive network. PIF/Cu-30 possessed an electronic conductivity of as high as 3.6 × 105 S m−1 at a bulk density of 0.26 g cm−3 and exhibited exceptional structural stability even after successive and harsh mechanical loads. Graphite with a mass load of 12 mg cm−2 was loaded into the PIF/Cu-30 to prepare the anode for cell assembly. The cells using PIF/Cu-30 achieved a better performance in capacity retention (98.2 %@60 cycles) than those using traditional Cu foils (55.1 %@60 cycles), which resulted from the fast transport of electrons and Li-ion through the 3D conductive networks in the porous PIF/Cu-30.

Flammability and Mechanical Testing of Sandwich Composite for Rolling Stock Structural Applications

Components made of composite materials are being increasingly used in the construction of rolling stock. Currently, the use of components made of composite materials as train structural elements is increasingly being considered. Non-structural components made of composites are most often found inside rail vehicles (e.g., the interior lining), while structural components made of sandwich composite materials can be used for the roof, sidewalls, and underframe constructions. This article provides a description of an innovative sandwich composite developed for a metro’s underframe, as well as the production process and preparation of the composite specimens. The main parts of the work are flammability and mechanical (static and fatigue) tests of the innovative sandwich composite. The scope of the flammability tests included the testing of the fire properties using the radial plate method, the optical density of smoke, and the content of toxic gases. The mechanical strength of the sandwich composite was examined during a flexural (three-point bending) test and a fatigue strength under a given dynamic load. The results presented in the article are very significant, both in terms of flammability and the mechanical strength tests. In order to produce large-size train components, appropriately large patches of component layers of the composite are required; this may pose production problems.

Hydrogel Containing Propolis: Physical Characterization and Evaluation of Biological Activities for Potential Use in the Treatment of Skin Lesions.

Skin injury affects the integrity of the skin structure and induces the wound healing process, which is defined by a well-coordinated series of cellular and molecular reactions that aim to recover or replace the injured tissue. Hydrogels are a group of promising biomaterials that are able to incorporate active ingredients for use as dressings. This study aimed to synthesize hydrogels with and without propolis extract and evaluate their physical characteristics and biological activities in vitro for potential use as active dressings in the treatment of skin lesions. The antifungal [Candida albicans (C. albicans) and Candida tropicalis (C. tropicalis)] and antibacterial [Staphylococcus aureus (S. aureus), Pseudomonas aeruginosas (P. aeruginosas) and Escherichia coli (E. coli)] activity was assessed by the microdilution method in plates and antioxidant potential by the reduction of the phosphomolybdate complex. The hydrogels showed good water absorption capacity, high solubility, and high gel fraction, as well as good porosity, water retention, and vapor transmission rates. They revealed a totally amorphous structure. The extract and the hydrogels containing the propolis extract (1.0% and 2.5%) did not inhibit fungal growth. However, they showed antibacterial activity against strains of S. aureus and P. aeruginosas. Regarding the E. coli strain, only the extract inhibited its growth. It showed good antioxidant activity by the evaluation method used. Therefore, the hydrogels containing propolis extract can be a promising alternative with antibacterial and antioxidant action for use as dressings for the treatment of skin lesions.

Integral LOCA experiments to study FFRD behavior of high burnup nuclear fuels

This paper introduces the Integral Loss Of Coolant (LOCA) facility (i-LOCA) established at Seoul National University. The facility was designed to investigate the integral fuel behavior of Light Water Reactors during LOCA, encompassing aspects such as cladding oxidation, ballooning and burst, reflood quenching, secondary hydriding, and fuel pellet dispersal. Integral LOCA experiments were carried out using three types of surrogate ZrO2 pellets, representing various segment burnups: cylindrical pellets with no fuel fragmentation (<55 GWd/MTU), mixed fragments of different sizes simulating ∼68 GWd/MTU (D = 0.3, 0.5, 1.0, 2.0, 3.0, and 5.0 mm with the same mass fraction), and small single powdered fragments simulating ultra-high burnup fuel (D = 0.5 mm, ∼94 GWd/MTU). Zr-Nb-Sn, Zr-1.1Nb, and Cr-coated (15 μm, Arc Ion Plating) Zr-1.1Nb ATF cladding were employed, with rod internal pressures ranging from 1 MPa to 7 MPa. The burst size and hoop strain exhibited significant variations depending on the type of surrogate pellets used, with larger burst sizes and hoop strains observed for smaller average diameters of surrogate pellets due to the effect of azimuthal and axial temperature distribution. Fuel dispersal was influenced by rod internal pressure, burst size, and the size of pellet fragments. Only pellet fragments smaller than the burst hole width underwent dispersal upon fuel burst, while larger fragments blocked the dispersal of smaller fragments. The rapidly escalating average dispersal fraction of single powder compared to mixed powder indicated a threshold burnup for fuel dispersal between 69–94 GWd/MTU. Cladding inner oxidation length was influenced by burst hole size and remaining fuel pellets. The results of inner oxidation confirmed the validity of the U.S. NRC’s assumption regarding the length of inner wall oxidation. The tested 15 μm Cr-coated cladding tubes, produced using the arc ion plating method, exhibited no significant differences in burst geometry, fuel dispersal, inner oxidation, and secondary hydriding when compared to the uncoated reference cladding.

A comparative study of blood viscometers of 3 different types.

The greater the viscosity of the blood, the more difficult its flow becomes, leading to an increased incidence of diseases caused by blood circulation disorders. These diseases are commonly associated with the cardiovascular and cerebrovascular systems. High blood viscosity is a primary cause of circulatory system diseases. Studies have shown that accurately measuring blood viscosity and applying this data in clinical trials can help prevent circulatory system diseases. Viscosity data can vary depending on the measurement methods used, even when these methods are based on hydrodynamic principles. Despite using approved blood viscometers, the results often differ depending on the type of viscometer used, potentially causing confusion within the medical field. Informing the medical community about these differences and the level of error associated with each measurement method can help reduce this confusion. To our knowledge, the degree of difference in viscosity measurement results due to different measurement methods and the reasons for these differences have not yet been thoroughly explored. In this study, we selected three blood viscosity measurement methods registered with the Ministry of Food and Drug Safety of Korea to analyze the same canine blood. The viscosity measurements were carried out using each device and compared. The parallel plate and scanning capillary methods yielded similar viscosity values, while the cone plate method showed lower viscosity values. The viscosity of blood, as measured by the three viscometers, differed, indicating that more experimental data must be accumulated to evaluate the cause of these differences. In this paper, we identified several causes of inconsistency and suggested measures to avoid this confusion. However, confirming that the test results show systematic differences is expected to assist clinicians who diagnose and prescribe treatments based on blood viscosity results. The findings of this comparative study are anticipated to serve as a starting point for establishing guidelines or standards for blood viscosity measurement methods.

Structural Aspects, Binding Interactions, Biological Activity of Co(II)‐ and Ni(II)‐N′‐(2‐fluorobenzoyl)benzo[d]thiazole‐2‐carbohydrazide Chelatess

ABSTRACTN′‐(2‐Fluorobenzoyl)benzo[d]thiazole‐2‐carbohydrazide (OFBBTCH, HL) and its chelates with Co(II) and Ni(II) have been synthesized and characterized by elemental analysis, liquid chromatography‐mass spectrometry (LC–MS), Fourier transform infrared spectroscopy (FT‐IR), ultra‐violet visible (UV–vis), nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), and powder X‐ray diffraction. The conductance measurements reveal that the chelates are non‐electrolytic, and the spectral analysis indicates octahedral geometry of the chelates. The kinetic and thermodynamic parameters were obtained by Coats–Redfern relations, which shows positive Gibbs's free energy and negative entropy for both chelates. The equilibrium studies carried out by pH‐metry revealed the dissociation constant (pKa) of OFBBTCH as 8.13 and the formation of 1:1 and 1:2 Co(II)‐L and Ni(II)‐L complexes in solution. The CT‐DNA binding studies carried out by electron absorption, fluorescence quenching, steady state emissions and viscosity studies revealed hyperchromism and groove binding for HL and chelates. The Kb values calculated from electron absorption studies are 2.4 × 106, 4 × 106, and 9 × 106 M−1, from the fluorescence quenching studies Ksv values are 0.1722, 0.278, and 0.748 M−1, and Kapp values are 5.9 × 104, 1.3 × 105, and 2.9 × 105 M−1 for HL, Co(II)‐OFBBTCH and Ni(II)‐OFBBTCH, respectively. Bovine serum albumin (BSA) and human serum albumin (HSA) binding interactions were carried out by electron absorption and fluorescence quenching studies. The light switching properties of the chelates, the hydrolytic and oxidative cleavage of CT‐DNA, and the antioxidant properties were evaluated. Anti‐microbial studies carried out by pour plate method showed high activity for Ni(II)‐OFBBTCH chelate. Cytotoxicity of the compounds was performed for HeLa and MCF cell lines by MTT assay. Molecular docking studies revealed the docking of HL and Co(II)‐HL at the minor groove, and Ni(II)‐HL was docked at the major groove with hydrogen bonding.

Antibacterial Efficacy of Tryptophan Coordinated Silver Nanoparticles Against E. coli: Spectroscopic and Microscopic Evaluation of Bacterial Cell Death.

The capability of conventional fluorescence spectroscopy and right-angled synchronous fluorescence spectroscopy (SFS) was evaluated to quantify the antibacterial potential of chemically synthesized Tryptophan coordinated silver nanoparticles (Ag-TrpNPs). Silver nanoparticles have gained significant importance as a material of interest due to their diverse assemblies in the nanoscale range and their potent antibacterial activity. But due to toxicity of silver nanoparticles there is a dire need to coordinate these materials with some biocompatible and biodegradable molecules. The study has been focused on chemical synthesis of functional fluorescence nanomaterials based on Tryptophan molecules coordinated with silver nanoparticles (Ag-TrpNPs). The antibacterial activity of Ag-TrpNPs was assessed in bacteria due to their functional characteristics such as tuneability, biocompatibility, and bioavailability. We employed optical characterization techniques such as Ultraviolet-visible spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), fluorescence spectroscopy, and confocal microscopy to ensure the particles formation in aqueous suspension. DLS analysis confirmed the hydrodynamic size of the nanoparticles of approximately 100nm. SEM images revealed the spherical morphology and size distribution of the Ag-TrpNPs. Escherichia coli bacterial strains were used to assess the antibacterial efficacy of the Ag-TrpNPs using fluorescence spectroscopy and imaging. Initially, the agar well plate method was employed to evaluate the antimicrobial activity of the Ag-TrpNPs. The significant zones of inhibition of size 37mm at 500µg/mL and 27mm at 15.5µg/mL were reported which indicated the efficiency of Ag-TrpNPs from higher to lower concentration. Conventional and synchronous fluorescence spectra provided evidence of bacterial cell death in aqueous suspensions to ensure the interaction of Ag-TrpNPs with E. coli bacteria at different times and concentrations. SEM was employed to investigate the interaction mechanism between Ag-TrpNPs and bacterial cells. The images revealed cell wall disintegration, leading to the leakage of cellular contents, and eventually cell death occurred.

A novel strategy for activation technique for 6H-SiC substrates in electroless Ni-P plating processes

This study proposes a novel iron wire activation method for electroless Ni-P plating on 6H-SiC substrates, offering a sustainable alternative to traditional metal activation techniques, focusing on the surface roughness effect on the microhardness and Ni-P plating efficiency of 6H-SiC substrates. This experimental approach reveals insights into the relationship between substrate morphology and plating characteristics. It is found that the plating thickness (33.82 μm) of the non-polished substrates closely matched the expected (33.26 μm), with a deposition rate of 6.65 μm/h, which underscores the precision regulation of the plating process. In contrast, despite the faster deposition rate of 9.20 μm/h of the polished S500 substrate, it exhibited a minor thickness discrepancy, suggesting a saturation point in the deposition dynamics on fully polished surfaces. The research additionally sheds light on the adhesion characteristics of the plated layers, particularly emphasizing the role of surface roughness. Remarkably, non-polished substrates demonstrated better adhesion, categorized as HF3, indicating a significantly stronger bond compared to the polished substrates, which were categorized as HF4 to HF6. This distinction in adhesion categories underlines the critical influence of substrate morphology on the quality of the Ni-P layer's adherence.