Solid Plate Research Articles

Unique Leishmania mexicana clones secrete populations of extracellular vesicles with unique protein profile and variable infectious capability

The study of extracellular vesicles has become an incredibly important field of study, but the inherent heterogeneity of these vesicles continues to make their study challenging. The genetic variability and well-documented protocols for the growth and vesicle isolation from Leishmania parasites provide a unique opportunity to compare the heterogeneity of different populations secreted by Leishmania clones. Leishmania mexicana was cultured on solid SDM agar plates and 8 clonal colonies were selected. The EVs collected from the liquid cultures of these 8 clones were assessed by NTA, TEM, and proteomic analysis. We found that all 8 clonal L. mexicana cultures were visually indistinguishable from each other and had similar growth rate, and these physical similarities extended to their EVs. However, proteomic analysis reveals that the EVs collected have unique protein profiles compared to each other and EVs isolated from a heterogeneous liquid culture of L. mexicana. We selected 3 clonal EVs for further mouse infection experiments and found that EVs from CL7 L. mexicana consistently caused reduced footpad swelling in C57BL6 mice footpads compared to EVs from CL1, CL8, and heterogenous L. mexicana. This trend was not observed when infecting Balb/C mice and C57BL6 with the parasites alone, with only CL1 L. mexicana causing significantly increased infection in Balb/c mice. Our results together show that EVs isolated from different clonal colonies of L. mexicana have distinct differences in protein cargo which can lead to varying outcomes on Leishmania infection. Further evaluation will be needed to determine the underlying mechanisms behind this and verify that differences observed in infectivity are directly caused by variations between our L. mexicana clones, especially genetic sequencing and immunoblotting to validate our results.

Genetic transformation of the freshwater diatom Cyclotella meneghiniana via bacterial conjugation

Diatoms, the most species-rich algae, produce the main primary productivity of marine and freshwater ecosystems. Though, genetic transformation has been established in a variety of marine diatoms, genetic modification of freshwater diatoms is still difficult to achieve. Centric diatom Cyclotella is a major genus of freshwater diatoms, and C. meneghiniana is the most well-known and intensively studied species in this genus. In this study, episomal plasmids for C. meneghiniana were constructed, and endogenous promoters of fucoxanthin chlorophyll a/c-binding protein 3 gene (Fcp3) or ribosomal protein L14 gene (RL14) were used to drive the expression of blasticidin-S deaminase gene (bsr), enhanced green fluorescent protein gene (eGFP) and β-glucuronidase gene (GUS). The plasmids were introduced into algal cells by bacterial conjugation, and transformants were obtained by screening on solid plates containing 0.2 μg mL−1 blasticidin-S with the transformation efficiency of 9–58 transformants per 106 cells. PCR analysis verified the transfer of the plasmid sequences in the cells, and the fluorescence detection and staining analysis demonstrated that eGFP and GUS proteins were expressed in the cytoplasm, indicating the successful and stable expression of exogenous genes in C. meneghiniana through bacterial conjugation.

Finite element structural analysis of simply supported solid and stiffened plates: A comparative study

A structure’s form and shape influence how it behaves when loaded. This was achieved by contrasting the stiffened plate’s performance with that of a solid plate made of the same material and volume. The results have demonstrated that bending stress in stiffened plates is decreased when a solid plate of the same material and volume is transformed into a stiffened plate. Because stiffened plates have a higher strength to weight ratio than solid plates, this supports the recommendation of stiffened plates for a variety of technical applications. In order to determine the impact of stiffener orientation on bending stress reduction in stiffened plates, additional investigations were carried out on a number of plates. An investigation was carried out to determine the ideal stiffener angle in a stiffened plate that could offer the least amount of stress. The current work offers insightful information about particular stiffened plate design characteristics that can be used in a variety of engineering contexts.

PLA/PCL composites manufactured from commingled yarns for biomedical applications

Composites manufactured with textiles weaved with commingled yarns using PLA (polylactic acid) and PCL (polycaprolactone) fibres are promising candidates for connective tissue engineering. In this work, textiles were fabricated using PLA/PCL commingled yarns in a ratio of 3 to 1, which were subsequently consolidated by compression moulding to produce solid composite plates. Specimens were extracted from the composite plates and submitted to degradation testing by immersion in PBS fluid (phosphate-buffered saline) at different periods. The dry mass, mechanical performance (tensile tests), thermal properties and molecular weight evolution, and cell compatibility by direct and indirect testing were evaluated and discussed. The results obtained demonstrated the material viability for connective tissue (tendon/ligament) repair and substitution.

EFFECT OF EXTERNAL HARMONIC VIBRATION ON THE FORMATION OF SOLITARY WAVES IN FALLING TWO-LAYER LIQUID FILMS

Abstract We study the influence of a low-frequency harmonic vibration on the formation of the two-dimensional rolling solitary waves in vertically co-flowing two-layer liquid films. The system consists of two adjacent layers of immiscible fluids with the first layer being sandwiched between a vertical solid plate and the second fluid layer. The solid plate oscillates harmonically in the horizontal direction inducing Faraday waves at the liquid–liquid and liquid–air interfaces. We use a reduced hydrodynamic model derived from the Navier–Stokes equations in the long-wave approximation. Linear stability of the base flow in a flat two-layer film is determined semi-analytically using Floquet theory. We consider sub-millimetre-thick films and focus on the competition between the long-wavelength gravity-driven and finite wavelength Faraday instabilities. In the linear regime, the range of unstable wave vectors associated with the gravity-driven instability broadens at low and shrinks at high vibration frequencies. In nonlinear regimes, we find multiple metastable states characterized by solitary-like travelling waves and short pulsating waves. In particular, we find the range of the vibration parameters at which the system is multistable. In this regime, depending on the initial conditions, the long-time dynamics is dominated either by the fully developed solitary-like waves or by the shorter pulsating Faraday waves.

Stable and unstable fall motions of plate-like ice crystal analogues

Abstract. The orientation of ice crystals affects their microphysical behaviour, growth, and precipitation. Orientation also affects interaction with electromagnetic radiation, and through this it influences remote sensing signals, in situ observations, and optical effects. Fall behaviours of a variety of 3D-printed plate-like ice crystal analogues in a tank of water–glycerine mixture are observed with multi-view cameras and digitally reconstructed to simulate the falling of ice crystals in the atmosphere. Four main falling regimes were observed: stable, zigzag, transitional, and spiralling. Stable motion is characterised by no resolvable fluctuations in velocity or orientation, with the maximum dimension oriented horizontally. The zigzagging regime is characterised by a back-and-forth swing in a constant vertical plane, corresponding to a time series of inclination angle approximated by a rectified sine wave. In the spiralling regime, analogues consistently incline at an angle between 7 and 28°, depending on particle shape. Transitional behaviour exhibits motion in between spiral and zigzag, similar to that of a falling spherical pendulum. The inclination angles that unstable planar ice crystals make with the horizontal plane are found to have a non-zero mode. This observed behaviour does not fit the commonly used Gaussian model of inclination angle. The typical Reynolds number when oscillations start is strongly dependent on shape: solid hexagonal plates begin to oscillate at Re =237, whereas several dendritic shapes remain stable throughout all experiments, even at Re > 1000. These results should be considered within remote sensing applications wherein the orientation characteristics of ice crystals are used to retrieve their properties.

Accounting of imperfect interfaces in multilayer modeling

Multilayer systems are widely used in industry for their performances as compared with homogeneous materials. The layers are usually glued together but the bonding may be imperfect (air bubble, detachment). The interfaces are generally modeled as sliding or bonded. These two behaviors can be significantly different and the actual behavior is generally somewhere in between. The vibroacoustic behavior of the structure is thus modified by the imperfect interface. Several models have been implemented to describe the dynamic behavior of multilayer systems with imperfect interfaces. In this paper, we propose an analytical model of imperfect interfaces based on the Transfer Matrix Method (TMM). Two computations are performed in parallel (one with a perfectly bonded interface and the other with a sliding interface). Instead of mixing impedances or admittances matrices, a mixing law on the state variables is applied, resulting in an equivalent global matrix which can be coupled in any multi-layer. The model is compared in terms of the sound absorption or sound transmission loss with the existing ones and is applied on different classical multilayer systems with multi-layered solid plates and a multilayer composed of a porous layer with a heavy layer which is widely used in the automotive industry.

Harnessing blue light for cost-effective and eco-friendly antimicrobial solutions in poultry farming

Blue light in the visible spectrum naturally fights bacteria and effectively deactivates various Gram-positive and Gram-negative bacteria and fungi using photodynamic processes. It works against drug-resistant strains within these species and is gentler on mammalian cells than ultraviolet rays or chemicals. This study evaluated blue light as an affordable way to sanitize surfaces in poultry settings, such as eggs and litter. The study used an light-emitting diode array to remove harmful Esche¬richia coli and Staphylococcus aureus from these items and observed how blue light affected their survival rates. Blue light (455 nm) at 30 mW/cm2 for one hour decreased the survival of S. aureus and E. coli on solid agar plates to 29.88% and 21.04%, respectively, compared to non-irradiated cultures. Similarly, on untreated surfaces (such as plastic used for feeding and drinking), the survival rates dropped to 25.8% and 15.6%, respectively. The survival percentages on treated eggs were 50% (S. aureus) and 48.2% (E. coli) and 59% (S. aureus) and 36.46% (E. coli) on treated litter. Hence, blue light technology offers a promising alternative to traditional antimicrobial methods by leveraging specific wavelengths to target microbial cells. This approach can significantly reduce the microbial load in poultry environments, enhancing food safety and animal health. This paper reports the first use of blue light as an antibacterial within poultry research in Iraq, offering a fresh approach to disinfection in this field.

Numerical modeling of the impact of a large scale waterfall on a solid plate

Recent hydroelectric power plant safety developments have necessitated detailed studies on dam spillway operations, especially during emergency water discharge scenarios such as overtopping. This paper presents a numerical investigation of a 10-meter high waterfall impinging on a solid plate using two-phase flow models. Our approach integrates a coupled Eulerian–Lagrangian Spray Atomization (ELSA) model with an Interface Capturing Method (ICM) to simulate the complex multiphase flow and atomization processes. Our model proficiently mapped the velocity and turbulence within the pre-impact region. To refine the accuracy of the impact pressures, we isolated this zone and implemented the Injection–Reinjection strategy, a novel numerical procedure for this type of configuration. The study reveals significant insights into the dynamic interactions of water packets with the dam structure, highlighting critical impact pressures that can influence dam stability and integrity. Our results, compared against experimental data, demonstrate the effectiveness of the modeling strategies in predicting the fluid behaviors and the subsequent pressures exerted on structural components.

Full-scale experimental study on tribological performance of FPBs for highway bridges with various solid lubricants under fast loading

Friction pendulum bearings (FPBs) have proven to be effective for the seismic isolation of highway bridges. Previous studies often employed scaled model shaking table tests to investigate dynamic responses of the structures or quasi-static tests to assess the hysteretic performance of FPBs. However, it is noteworthy that the stress on the friction surface is reduced due to the size effect in scaled model in shaking table tests, while quasi-static tests of prototype bearings cannot simulate the sliding velocity experienced during seismic events, which is a sensitive parameter for the performance of FPBs with solid lubricant plates. Research on the performance of full-scale FPBs under fast frictional loading is very limited. This paper addresses this knowledge gap by studying the velocity demand for a highway bridge with FPBs and conducting fast sliding performance tests using full-scale FPBs. The results indicate that under a 0.2 g PGA earthquake, the velocity demand for FPBs can reach 0.5 m/s. Through testing full-scale FPBs at various loading speeds, it was found that solid lubricant plates by UHMWPE material exhibit poor thermal stability during wear tests, solid lubricant plates by PTFE material lack sufficient tangential tear strength under fast loading, and solid lubricant plates by PET material show good wear resistance but have a high breakaway force and levered maximum force during the running-in stage. Subsequently, this study developed ultra-high performance friction plate (UHPF) as the solid lubricant for FPBs, achieving ideal hysteretic performance under fast loading. The full-scale FPB specimens in this paper are the ones manufactured for the continuous beam bridges in the Shenzhen-Zhongshan Sea-crossing Link project in China. The dimensions of the bearing, axial load, and loading speed is much more stringent than those in previous FPB tests, providing results that are highly important for engineering applications.

Numerical study of arrowhead, hexagonal, and concave shaped- elliptical perforated plate fin heatsinks to improve the hydrothermal performance factor

This study explores the comparison of plate fin heatsinks to address the escalating challenges and the growing demand for industrial cooling. Plate fin heatsinks may replace plane (baseline) heatsinks to improve heat transmission while retaining volume. The three novel shape designs: arrowhead fin, hexagonal fin, and concave fin are introduced which are missing in existing literature. The simulation is conducted for Reynolds number (Re) ranging from 13049 to 52195. Elliptical perforated arrowhead, hexagonal, and concave heatsinks have 16.06 %, 16.64 %, and 17.36 % lower volumes than solid arrowhead, hexagonal, and concave heatsinks. The Nusselt number improved by 65.47 %, 69.87 %, and 37.71 % respectively for elliptical perforated arrowhead fin, elliptical perforated hexagonal fin, and elliptical perforated concave fin compared to the rectangular plate fin at Re = 52915. The Nusselt number also enhanced by 23.22 %, 17.91 %, and 8.02 % for the solid arrowhead fin, solid hexagonal fin, and solid concave fin respectively compared to the baseline case at Re = 52195. The maximum HTPF is 1.23 and 1.72 for solid arrowhead plate fin and elliptical perforated hexagonal plate fin respectively. The result of this novel shaped heatsink is promising and can be used as a substitute of traditional plane fin for relevant industrial applications in future.

Experimental study of wave diffraction loads on a vertical circular cylinder with heave plates at deep and shallow drafts

This study focuses on wave diffraction loads influenced by heave plates at deep and shallow submerged depths. An extensive experimental campaign is conducted on a fixed vertical and free-surface piercing circular cylinder with five different circular plates, including a perforated plate. The horizontal and vertical wave forces are studied in monochromatic and bichromatic waves. The results show that the heave plate significantly influences the forces varying in time and representative harmonics, including sum- and difference-frequency components. The study found that wave steepness and submerged depth of the plate contribute to the nonlinearity of the loads and that the porous plate reduces the loads compared to the solid plate. Corresponding results from a boundary element method (BEM) solver, HydroStar, provide a reasonable prediction of the harmonics. However, the first harmonic of the vertical force is underpredicted at low frequencies, specifically where the BEM results indicate the cancellation of the forces. Dedicated computational fluid dynamics (CFD) simulations are carried out to investigate the discrepancy, and it is observed that flow separation occurs around the edge of the plate. A simplified approach based on Morison’s equation is employed to model the flow separation effects using a quadratic drag force calculated with a constant drag coefficient. The approach shows that viscous drag is the dominant contributor to vertical wave forces on the heave plate in the low-frequency regime.

Air-coupled ultrasound using broadband shock waves from piezoelectric spark igniters

We used an optomechanical sensor to study the ultrasound generated by manually operated piezoelectric spark igniters. These low-energy sparks produce short-duration acoustic shock-wave pulses, with sub-microsecond rise times and frequency content extending well beyond 2 MHz in air. The same source–receiver combination was then used to demonstrate broadband characterization of solid (polymer and glass) plates in a simple setup, where single spark events yielded high signal-to-noise ratio data without the need for critical alignment. This setup also enabled us to estimate pressure excursions approaching 105 Pa at millimeter-scale distances from the spark. The results are in large part made possible by the small size, wide bandwidth, and high sensitivity of the optomechanical sensor and might be of interest for air-coupled ultrasound applications in nondestructive testing.

The effect of wza gene deletion in Klebsiella pneumoniae on capsule formation and bacteriophage sensitivity

Objective: To investigate the effects of wza gene deletion in Klebsiella pneumoniae on capsule formation ability and bacteriophage sensitivity. Methods: The wza deletion mutant strain was constructed through a temperature-sensitive plasmid-mediated homologous recombination. The growth curves of W14 and Δwza were detected by measuring the optical density OD600. In order to analyze the effect of gene wza on bacterial capsule formation, wild-type strain W14 and Δwza mutant strain were detected by transmission electron microscope, and their capsule contents were measured by quantifying the uronic acid contents. The plaque assay was used to detect bacterial sensitivity to bacteriophage in wild-type strain W14 and Δwza mutant strain. The t test was used to compare whether there were differences in the contents of uronic acid in the capsules of wild-type strain W14 and Δwza mutant strain. Results: The PCR results revealed that the Δwza mutant strain was successfully constructed. Compared with wild-type strain W14, the growth curves of Δwza on the solid plates demonstrated a slightly slower growth. However, no difference in growth was observed among wild-type strain W14 and Δwza mutant strains in LB broth. The transmission electron microscope results showed that wza gene deletion resulted in the loss of capsule in bacteria. The uronic acid content assay suggested that the capsule content was significantly decreased in Δwza mutant strain (45.963±2.795) μg/ml compared with wild-type strain W14 (138.800±5.201) μg/ml. There was a statistical difference between the two groups (t=27.233, P<0.001). The plaque assay indicated that bacteria lost its sensitivity to bacteriophage when gene wza was deleted. Conclusion: Deletion of the wza gene impairs bacterial capsule formation ability and can affect bacterial sensitivity to bacteriophage phiW14.

A lateral flow immunoassay for the rapid identification of Candida auris from isolates or directly from surveillance enrichment broths.

Candida auris is a recently discovered yeast with a multi-drug resistant profile associated with high mortality rates. The rapid identification of Candida auris in hospital settings is crucial to allow appropriate therapeutic and rapid implementation of infection management measures. The aim of this study was to develop a lateral flow immunoassay (LFIA) for the rapid identification of Candida auris. Highly specific monoclonal antibodies were obtained by immunizing mice with membrane proteins from Candida auris which were then used to develop a LFIA whose performance was assessed by testing 12 strains of Candida auris and 37 strains of other Candida species. Isolates were grown on either Sabouraud dextrose, CHROMagarTM Candida Plus or HardyCHROMTM Candida + auris agar plates. The strains were also cultured on salt sabouraud-dextrose with chloramphenicol or a commercially available Salt-Sabouraud Dulcitol Broth with chloramphenicol and gentamicin, and processed using a simple centrifugation protocol to recover a pellet. Finally, the colonies or yeast extract were transferred to the LFIA to determine the specificity and sensitivity of the assay. The LFIA reached 100% specificity and sensitivity from solid agar plates. For both enrichment broths, some Candida non-auris species were able to grow, but the LFIA remained 100% specific. The use of a dextrose-based sabouraud broth resulted in earlier identification with the LFIA, with most of the Candida auris strains detected at 24 h. The developed LFIA prototype represents a powerful tool to fight the emerging threat of Candida auris. Clinical validation represents the next step.

Study the Effect of Suction-Injection parameters Numerically and Analytically for Magneto hydrodynamic Jeffery Hamel Fluid Flow Problem

This paper processes numerically and analytically the magnetohydrodynamic flow among two porous solid plate intersections at an angle or through non-parallel porous walls, which can be interpreted as a mix of Jeffery Hamel fluid flow additives from suction-injection parameters. In fluid mechanics, the equations of governing, which are transferred to the non-linear ordinary differential equation of third order, are modeled instead of the conventional Navier-Stokes equations by Maxwell's electromagnetism. Results obtained from the DTM and the numerical method BVP4c are compared to those resulting from the optimal methods (ODTM), which consist of the collocation differential transform method (CDTM), the sub-domain differential transform method (SDTM), the least squares differential transform method (LSDTM), and the Galerkin differential transform method (GDTM). A comparison is made between the approximate analytical and numerical solutions for different parameters like open angles (ε), Reynolds numbers (Re), injection parameters (S), and Hartmann numbers (Ha). The results demonstrate that the two approaches are very similar.

Design and thermal-hydraulic analysis of multi-target system with 100 MeV proton linear accelerator for the production of 67Cu and 68Ge radioisotopes

Radioisotopes are widely used in the fields of medicine, science, and industry. The growing demand for medical radioisotopes has driven research on alternative production methods. In particular, both isotopes of 67Cu and 68Ge play vital roles in the medical environment in many countries to be used in the radio-immunotherapy and the positron emission tomography imaging, respectively. This study designed a multi-target system consisting of two Zn and one Ga2O3 plates to enable simultaneous production of the medical radioisotopes 67Cu and 68Ge using 100 MeV proton beams. To understand the thermal effect on the multi-targets, we examined the distribution of energy absorbed in each solid plate target when exposed to an accelerated proton beam through the thermal-fluid analysis based on ANSYS simulation. For confirming thermal stability for two Zn targets and one Ga2O3 target, the modified water flow path inside the multi-target system was designed effectively with the controlled distribution of multiple sub-holes between main inlet and the following four channels. It was confirmed that the newly designed multi-target system of Zn and Ga2O3 solid plates shows higher thermal stability than the case of uniform distribution of water inlet, which means it could be exposed to a higher current beam of 7.57% to decrease the processing time.

Drop Behavior on Heterogeneous Ratchet-Structured Substrates Harmonically Vibrated in Lateral Direction.

We analyze numerically a new ratchet system: a liquid drop is sitting on a heterogeneous ratchet-structured solid plate. The coated plate is subject to a lateral harmonic oscillation. The systematic investigation performed in the frame of a phase field model shows the possibility of realizing a long-distance net-driven motion for isolated domains of the forcing parameters. The studied problem might be of considerable interest for controlled motion in micro- and nanofluidics.

Sealing solid agar in serum bottles for rapid isolation and long-term preservation of chemoautotrophic ammonia-oxidizing bacteria

Ammonia-oxidizing bacteria (AOB) are ubiquitous on the earth and have broad applications in bioremediation. However, the number of their species with standing in nomenclature and deposited in Microbial Culture Collections still remains low. Moreover, only a few novel species have been reported over the last decades. In this study, we sealed agar in serum bottles to develop a kind of solid agar plate with the oxygen concentration in the headspace maintained at low levels. By using these plates, eight AOB isolates including two novel species were obtained. When AOB cells were grown on the sealed solid agar plates, the time to form visible colonies was largely reduced and the maximum diameter of colonies reached 2 mm, which makes the process of AOB isolation rapid and efficient. Based on five AOB isolates, the headspace oxygen concentration had a significant influence on AOB growth either on solid plate or in liquid culture. Especially, when grown under 21 % O2, the number of colonies formed on solid agar plates was very low and sometimes no visible colony formed. Besides the application on AOB isolation, the sealed solid agar plate was also effective for the enumeration and preservation of AOB cells. When preserved under room temperature for more than ten months, the AOB colonies on the plate could still be recovered. This method provides a feasible way to isolate more novel AOB species from the environment and deposit more species in Microbial Culture Collections.

Evaluation of new generation fungicides against Ganoderma induced basal stem rot of oil palm

Basal stem rot (BSR), incited by Ganoderma spp. poses a significant challenge to the oil palm industry in India. A total of ten roots and basidocarps samples were taken from BSR-infected fields of Pedavegi, Andhra Pradesh, and identified as Ganoderma based on distinctive colony characters. To enhance identification accuracy, PCR with GB4 genus-specific primers, resulting in a 500 bp amplicon that confirmed the isolate affiliation with the Ganoderma genera. The efficacy of 13 fungicides against Ganoderma was evaluated through solid plate assay. Noteworthy inhibition of mycelial radial growth was observed with the eight fungicides at all tested doses, including Hexaconazole 5 per cent SC, Propiconazole 25 per cent EC, Tebuconazole 25.9 per cent EC, Tebuconazole 50% + Trifloxystrobin 25% w/w WG, Propiconazole 13.9% + Difenconazole 13.9%, Fluopyram 17.7% w/w + Tebuconazole 11.4% SC, Azoxystrobin 8.3% + Mancozeb 66.7% WDG and Pyraclostrobin 5% + Metiram 55% WG. Complete inhibition was achieved at 2000 and 4000 ppm with Triflumizole 42.14% SC and Azoxystrobin 18.2% + Difenoconazole 11.4% SC. Additionally, the liquid broth assay validated the efficacy of five fungicides in hindering mycelial dry weight. Furthermore, effective strategies against BSR, such as root feeding, stem injection and soil drenching, emerged as valuable insights for the integrated Ganoderma management in plantation crops.. KEYWORDS :Basal stem rot, fungicides, Ganoderma, management, oil palm