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Experiments using multi-step protocols often involve several restrictions on the randomization. For a specific application to in vitro testing on microplates, a design was required with both a split-plot and a strip-plot structure. On top of two-level treatment factors and the factors that define the randomization restrictions, a multi-level fixed blocking factor not involving further restrictions on the randomization had to be added. We develop a step-by-step approach to construct a design for the microplate experiment and analyze a response. To consolidate the approach, we study various alternative scenarios for the experiment.Supplementary materials accompanying this paper appear online [ABSTRACT FROM AUTHOR]

Due to the overuse of antibiotics, the number of multidrug-resistant pathogen bacteria is rising in recent years posing a serious threat to human health. One promising alternative for treatment is the application of phage therapy using highly selective bacteriophages. Because of their selectivity, individual screens called phagograms for each patient are required to select phages from a phage library. Phagograms are mostly performed via bacterial cultivation on double layer agar plates and phage addition causing bacterial lysis. However, these assays are work-intensive and have a low ability for parallelization and automation. Hence, highly parallelizable and automatable microbioreactors in the lowest microliter scale could offer an economic solution increasing the throughput of phagograms. This paper demonstrates the applicability of a novel capillary-wave microbioreactor (cwMBR) to perform phagograms. Due to its small volume of only 7 µL and the open-droplet design, it can be easily automated and parallelized in future. Furthermore, the ability of online biomass measurement makes the cwMBR a perfect phagogram platform in the future. Herein, phagograms with E. coli and different concentrations of the phages MM02 and EASG3 were performed as proof of concept for phagograms in the cwMBR. Thereby, the cwMBR was able to measure differences in lysis kinetics of different phages. Furthermore, the phagograms were compared to those in conventional microtiter plate readers revealing the cwMBR as ideal alternative for phagograms as it combines favorable mixing conditions and a phage repellent hydrophilic glass surface with online biomass measurement in an open-droplet design for future parallelization and automation. [Display omitted] • Phage sensitivity tests called phagograms are mandatory for phage therapy. • State of the art phagograms are not highly parallelizable and automatable. • Novel capillary-wave microbioreactor (cwMBR) can perform parallelized phagograms. • cwMBR combines parallelizability and automatability with online biomass measurement. • cwMBR is able to measure lysis kinetics of phages. [ABSTRACT FROM AUTHOR]

A new high-throughput optical sensor for captopril (CAP) is proposed. The sensor is based on the inhibitory effect of the analyte on the specific reaction of desferal with Fe(III) in an acidic medium. The whole analytical scheme was developed in micro-plates format combined with instrumental-free detection through an overhead book scanner. Dissolution testing was selected as an interesting application due to the generation of large amounts of samples during drug development. The method allowed the quantification of CAP up to 500 μM, with a lower limit of quantification LLOQ of 25 μM. 96 samples/standards could be processed simultaneously, obtaining a complete dissolution profile within 1 h (n = 12). Following validation, the obtained results were in accordance with the HPLC method recommended by the US Pharmacopeia. Finally, the greenness of the procedure was assessed by well-established tools such as the Green Analytical Procedure and Blue Applicability Grade indexes (77.5% score). [ABSTRACT FROM AUTHOR]

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Background: Carbapenem-resistant A. baumannii pose a serious threat, limiting treatment options for severe infections induced by this emerging pathogen. This study aimed to evaluate the antimicrobial resistance profile and detect resistance mechanisms in imipenem-resistant A. baumannii from various Egyptian hospitals. Materials and Methods: A total of 59 A. baumannii isolated from various clinical specimens (blood, sputum, wound swap, urine and endotracheal tubes) collected from the microbiology lab of different Egyptian hospitals. Isolates were identified using conventional bacteriological methods. Antimicrobial susceptibility was tested using Kirby-Bauer disc diffusion method. Biofilm formation was determined spectrophotometrically using microtiter plate method. Metallo-β-lactamase (MBL) resistance was determined by combined disk test (CDT). Multiplex PCR evaluated MBL-encoding genes in imipenem-resistant isolates. Additionally, PCR was used to detect class 1 integrons in MBL-producing isolates. Results: Strong biofilm production was observed in 74% (17/23) of isolates. Class 1 integron was detected in 78.9 % (15/19) of MBL producing isolates. Out of 23 isolates 19 (32.2%) were MBL producers by CDT. Among the 19 (32.2%) CDT-positive isolates, 11 (57.9%) isolates harboured MBL encoding gene (blaNDM). Conclusion: Our findings highlight the emergence and dissemination of blaNDM in our hospitals, coupled with their biofilms and MBL production ability, represents a major public health challenge. The presence of class 1 integrons in all isolates carrying MBL-encoding gene, suggesting the critical role of Class 1 integrons in the dissemination of resistance genes. [ABSTRACT FROM AUTHOR]

A urea quantification method integrated with a pipette-tip-based biosensor and a smartphone was developed for the on-site diagnosis of blood urea nitrogen. When a sample solution containing phenol red is drawn into a pipette tip with urease immobilized on its inner wall, the color of the solution changes owing to an enzymatic reaction. The urea concentration can be quantified by photographing the pipette tip with a smartphone and quantifying the color intensity of the solution. In actual urea measurements, the detection limit (3σ) was estimated to be 1.3 mg/dL, indicating that the method has sufficient performance to quantify urea in serum. Furthermore, the method was found to reduce sample consumption and analysis time to 1/10 and 1/3, respectively, compared with conventional methods using microwell plates. This method requires only a micropipette and a smartphone to carry out measurements and does not require bench-top precision equipment or special training. Therefore, the method is expected to develop into a practical analytical platform for biomarker diagnostics that can be used in the field. [ABSTRACT FROM AUTHOR]

In disciplines like toxicology and pharmacology, oxygen (O2) respiration is a universal metric for evaluating the effects of chemicals across various model systems, including mammalian and microalgal cells. However, for these cells the common practice is to segregate populations into control and exposure groups, which assumes direct equivalence in their responses and does not take into account heterogeneity among individual cells. This lack of resolution impedes our ability to precisely investigate differences among experimental groups with small or limited sample sizes. To overcome this barrier, we introduce SlipO2Chip, an innovative glass microfluidic platform for precisely quantifying single-cell O2 respiration in the coordinated absence and presence of chemical solutes. SlipO2Chip comprises a wet-etched fused silica channel plate on the top and a dry-etched borosilicate microwell plate at the bottom. The microwells are coated with Pt(II) meso-tetra(pentafluorophenyl)porphine (PtTFPP), an O2 sensing optode material and an O2-independent reference dye. A custom 3D-printed holder facilitates the controlled horizontal movement ('slipping') of the channel plate over the microwell plate, thereby establishing or disrupting the fluid path over microwells. Collectively, these design elements enable the immobilization of single-cells in microwells, their exposure to controlled fluid flows, the coordinated opening and closing of microwells and repeated measurements of single-cell O2 respiration. Uniquely, by sequentially executing opening and closing it becomes possible to measure single-cell respiration prior to and after exposure to chemical solutes. In a proof-of-concept application, we utilized SlipO2Chip to measure the impact of increasing exposures of the marine bacterial signal 2-heptyl-4-quinolone (HHQ) on the dark respiration of the diatom Ditylum brightwellii at single-cell resolution. Results revealed a concentration-dependent decrease in per-cell O2 dark respiration, with a maximum reduction of 40.2% observed at HHQ concentrations exceeding 35.5 μM, and a half-maximal effective concentration (EC50) of 5.8 μM, consistent with that obtained via conventional bulk respiration methods. The ability of SlipO2Chip to sequentially assess the effects of chemical substances on single-cell O2 metabolism is advantageous for research where sample volumes are limited, such as clinical biopsies, studies involving rare microbial isolates, and toxicological studies aiming to address exposure effects while accounting for cell-to-cell variability. [ABSTRACT FROM AUTHOR]

AbstractThis research paper investigates the complex dynamics of Love wave propagation on a piezoelectric plate situated atop a micropolar elastic half-space having imperfect interface. The study delves into the multifaceted effects of flexoelectricity, micro-inertia, guiding layer thickness, and interfacial imperfection on the characteristics of Love waves. The electromechanical coupling factor which is significant in analyzing SAW device performances is also studied. Variable separable method is used to solve the governing equations and desired solution is obtained analytically. The findings contribute to a deeper understanding of Love wave propagation in complex elastic structures and development of advanced sensors and communication technologies. [ABSTRACT FROM AUTHOR]

In the present study, the isogeometric numerical solving process incorporating non-uniform rational B-splines is put to use to analyze the size-dependent thermal postbuckling behavior of porous functionally graded (FG) microplates having a central cutout with different shapes. Accordingly, the modified couple stress continuum elasticity is employed within the framework of a hybrid-type quasi-3D higher-order plate theory to take the through-thickness deformations into consideration by only four variables. On the basis of a refined power-law function together with the Touloukian scheme, the porosity-dependent as well as temperature-dependent material properties are achieved. The couple stress-based thermal postbuckling equilibrium paths are acquired corresponding to various geometrical and material parameters and different boundary conditions. It is found that the gap between thermal postbuckling equilibrium paths relevant to various patterns of the porosity dispersion is a bit higher for the couple stress-based case than the classical one. Furthermore, it is indicated that a central cutout causes to change the trend of the load-deflection response that leads to decrease the initial thermal postbuckling strength, while it enhances the microplate strength in deep thermal postbuckling region. [ABSTRACT FROM AUTHOR]

In this paper, size-dependent static bending and also free and forced vibration analyses of composite microplates are studied based on the modified couple stress theory (MCST) and quasi-3D sinusoidal shear deformation theory. The composite microplate is composed of epoxy reinforced with functionally graded graphene nanoplatelets (GPLs). The governing equations are derived utilizing Hamilton's principle and are solved for simply supported microplate using Navier's approach. The accuracy of the presented solution is confirmed and the effects of various parameters on the static and dynamic deflections and natural frequencies of the microplate are investigated including material length scale parameter and surface area, thickness, mass fraction, and distribution pattern of the GPLs. Numerical results confirm that subjoining the GPLs to the polymer reduces the static and dynamic deflections of the microplates and increases the natural frequencies. It is concluded that to achieve the highest reduction in the static and dynamic deflections and the highest growth in the natural frequencies, it is more helpful to use the GPLs with the larger surface areas and put them as far as away from the neutral surface of the microplate. [ABSTRACT FROM AUTHOR]

This study aimed to obtain a lentinan-specific fluorescent probe for the in situ visualization of lentinan. A carbohydrate-binding module with potential lentinan-binding capacity was discovered in a β-1,3-D-glucanase by using the bioinformatics techniques, and further recombinantly expressed. The binding specificity of the expressed protein, which was named as LBM was determined by the microtiter plate assays. The results indicated that LBM displayed a desired specificity for lentinan. The protein exhibited positive binding signals to lentinan, while could not bind to several examined polysaccharides including barley β-glucan, curdlan, or konjac glucomannan. Furthermore, the first lentinan-specific fluorescent probe was successfully constructed by fusing LBM with a green fluorescent protein EmGFP, based on which the in situ visualization of lentinan in Lentinula edodes was realized. It was shown that lentinan was not only presented in the mycelial cell wall, but also amorphously distributed in the interstitial space and inside the cell. The construction of the EmGFP-LBM provided a promising tool for the in situ visualization of lentinan. [ABSTRACT FROM AUTHOR]

This work develops a Hermitian C differential reproducing kernel interpolation meshless (DRKIM) method within the consistent couple stress theory (CCST) framework to study the three-dimensional (3D) microstructure-dependent static flexural behavior of a functionally graded (FG) microplate subjected to mechanical loads and placed under full simple supports. In the formulation, we select the transverse stress and displacement components and their first- and second-order derivatives as primary variables. Then, we set up the differential reproducing conditions (DRCs) to obtain the shape functions of the Hermitian C differential reproducing kernel (DRK) interpolant's derivatives without using direct differentiation. The interpolant's shape function is combined with a primitive function that possesses Kronecker delta properties and an enrichment function that constituents DRCs. As a result, the primary variables and their first- and second-order derivatives satisfy the nodal interpolation properties. Subsequently, incorporating our Hermitian C DRK interpolant into the strong form of the 3D CCST, we develop a DRKIM method to analyze the FG microplate's 3D microstructure-dependent static flexural behavior. The Hermitian C DRKIM method is confirmed to be accurate and fast in its convergence rate by comparing the solutions it produces with the relevant 3D solutions available in the literature. Finally, the impact of essential factors on the transverse stresses, in-plane stresses, displacements, and couple stresses that are induced in the loaded microplate is examined. These factors include the length-to-thickness ratio, the material length-scale parameter, and the inhomogeneity index, which appear to be significant. [ABSTRACT FROM AUTHOR]

Background: Vibrio natriegens, a halophilic marine γ-proteobacterium, holds immense biotechnological potential due to its remarkably short generation time of under ten minutes. However, the highest growth rates have been primarily observed on complex media, which often suffer from batch-to-batch variability affecting process stability and performance. Consistent bioprocesses necessitate the use of chemically defined media, which are usually optimized for fermenters with pH and dissolved oxygen tension (DOT) regulation, both of which are not applied during early-stage cultivations in shake flasks or microtiter plates. Existing studies on V. natriegens' growth on mineral media report partially conflicting results, and a comprehensive study examining the combined effects of pH buffering, sodium concentration, and medium osmolality is lacking. Results: This study evaluates the influence of sodium concentration, pH buffering, and medium osmolality on the growth of V. natriegens under unregulated small-scale conditions. The maximum growth rate, time of glucose depletion, as well as the onset of stationary phase were observed through online-monitoring the oxygen transfer rate. The results revealed optimal growth conditions at an initial pH of 8.0 with a minimum of 300 mM MOPS buffer for media containing 20 g/L glucose or 180 mM MOPS for media with 10 g/L glucose. Optimal sodium chloride supplementation was found to be between 7.5 and 15 g/L, lower than previously reported ranges. This is advantageous for reducing industrial corrosion issues. Additionally, an osmolality range of 1 to 1.6 Osmol/kg was determined to be optimal for growth. Under these optimized conditions, V. natriegens achieved a growth rate of 1.97 ± 0.13 1/h over a period of 1 h at 37 °C, the highest reported rate for this organism on a mineral medium. Conclusion: This study provides guidelines for cultivating V. natriegens in early-stage laboratory settings without pH and DOT regulation. The findings suggest a lower optimal sodium chloride range than previously reported and establish an osmolality window for optimal growth, thereby advancing the understanding of V. natriegens' physiology. In addition, this study offers a foundation for future research into the effects of different ions and carbon sources on V. natriegens. [ABSTRACT FROM AUTHOR]

Pancreatic β cells secrete insulin in response to elevated levels of glucose. Stem cell derived β (SCβ) cells aim to replicate this glucose-stimulated insulin secretion (GSIS) function, but current preparations cannot provide the same level of insulin as natural β cells. Here, we develop an assay to measure GSIS at the single cell level to investigate the functional heterogeneity of SCβ cells and donor-derived islet cells. Our assay involves randomly depositing single cells and insulin capture microbeads in opentop nanowells (40 × 40 × 55 μm³ ) fabricated on glass-bottom imaging microwell plates. Insulin secreted from single cells is captured on microbeads and then stained using a detection antibody. The nanowell microstructure limits diffusion of secreted insulin. The glass substrate provides an optically flat surface for quantitative microscopy to measure the concentration of secreted insulin. We used this approach to measure GSIS from SCβ cells and donor-derived islet cells after 15 minutes exposure to 3.3 mM and 16.7 mM glucose. Both cell types exhibited significant GSIS heterogeneity, where elite cells (<20%) produced the majority of the secreted insulin (55–78%). This assay provides an immediate readout of single cell glucose-stimulated insulin secretion in a flexible well plate-based format. [ABSTRACT FROM AUTHOR]

Cell line generation of mammalian cells is a time‐consuming and labor‐intensive process, especially because of challenges in clone selection after transfection. Antibiotics are common selection agents for mammalian cells due to their simplicity of use. However, the optimal antibiotic concentration must be determined with a kill curve experiment before clone selection starts. The traditional kill curve experiments are resource‐intensive and time‐consuming due to necessary sampling and offline analysis effort. This study, thus, explores the potential of online monitoring the oxygen transfer rate (OTR), as a non‐invasive and efficient alternative for kill curve experiments. The OTR is monitored using the Transfer‐rate Online Measurement (TOM) system and the micro(μ)‐scale Transfer‐rate Online Measurement (μTOM) device, which was used for mammalian cells first. It could be shown that the OTR curves for both devices align perfectly, affirming consistent cultivation conditions. The μTOM device proves effective in performing kill curve experiments in 96‐deep‐well plates without the need for sampling and offline analysis. The streamlined approach reduces medium consumption by 95%, offering a cost‐effective and time‐efficient solution for kill curve experiments. The study validates the generalizability of the method by applying it to two different CHO cell lines (CHO‐K1 and sciCHO) with two antibiotics (puromycin and hygromycin B) each. In conclusion, the broad application of OTR online monitoring for CHO cell cultures in 96‐deep‐well plates is highlighted. The μTOM device proves as a valuable tool for high‐throughput experiments, paving the way for diverse applications, such as media and clone screening, cytotoxicity tests, and scale‐up experiments. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a food-borne pathogen, which is often isolated from various seafood products. In this study, two kinds of bacteriophages was isolated from the offshore sediments samples. The anti-phage mutant strain were obtained after seventeen rounds of co-culture of Vibrio parahaemolyticus and mixed bacteriophage, multigroup sequencing was carried out on spontaneous the anti-phage mutant strain and the wild-type strain. We used the Sanger sequencing to verify the accuracy of the mutation sites. Biolog GEN III MicroPlates were used to evaluate the metabolic capacity of wild-type strains and the anti-phage mutant strain. In this study, we found that with flaG gene (slight homology to N terminus of multiple flagellins) mutated, making the bacteriophage unable to absorb to the cell surface of the host. And, the growth competitiveness of the anti-phage mutant strain is lower than the wild-type strain. These results indicated that the fitness cost, including loss of the growth competitiveness, constitutes a barrier to the prevalence of these defense mechanisms. And the selection pressure on different anti-phage strategies depends on the trade-off between mortality imposed by bacteriophages and fitness cost of the defense strategy under the given environmental conditions. In conclusion, this study provides valuable insights into the phagehost interaction and phage resistance in Vibrio parahaemolyticus. Our study provided knowledge for the evolutionary adaption of bacteria against the bacteriophage, which could add more information to understand the phage resistance mechanism before applying in the industry. [ABSTRACT FROM AUTHOR]

Immobilization is a key enabling technology in applied biocatalysis that facilitates the separation, recovery, and reuse of heterogeneous biocatalysts. However, finding a consensus immobilization protocol for several enzymes forming a multi‐enzyme system is extremely difficult and relies on a combinatorial trial‐and‐error approach. Herein, we describe a protocol in which 17 different carriers functionalized with different reactive groups are tested in a 96‐well microtiter plate to screen up to 21 immobilization protocols for up to 18 enzymes. This screening includes an activity and stability assay to select the optimal immobilization chemistry to achieve the most active and stable heterogeneous biocatalysts. The information retrieved from the screening can be rationalized using a Python‐based application CapiPy. Finally, through scoring the screening results, we find the consensus immobilization protocol to assemble an immobilized four‐enzyme system to transform vinyl acetate into (S)‐3‐hydroxybutyric acid. This methodology opens a path to speed up the prototyping of immobilized multi‐enzyme pathways for chemical manufacturing. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to look into the presence of plasmid-mediated quinolone resistance (PMQR) genes and biofilm formation in several species of clinical Shigella isolates that were resistant to quinolones. Methods: The stool samples of 150 patients (younger than 10 years) with diarrhea were collected in this cross-sectional study (November 2020 to December 2021). After cultivation of samples on Hektoen Enteric agar and xylose lysine deoxycholate agar, standard microbiology tests, VITEK 2 system, and polymerase chain reaction (PCR) were utilized to identify Shigella isolates. The broth microdilution method was used to determine antibiotic susceptibility. PMQR genes including qnrA, qnrB, qnrC, qnrD, qnrE, qnrS, qnrVC, qepA, oqxAB, aac(6′)-Ib-cr, and crpP and biofilm formation were investigated in quinolone-resistant isolates by PCR and microtiter plate method, respectively. An enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) technique was used to determine the clonal relatedness of quinolone-resistant isolates. Results: A total of 95 Shigella isolates including S. sonnei (53, 55.8%), S. flexneri (39, 41.1%), and S. boydii (3, 3.2%) were identified. The highest resistance rates of the isolates were against ampicillin (92.6%, n = 88/95). Overall, 42 of 95 (44.2%) isolates were simultaneously resistant against two or more quinolones including 26 (61.9%) S. sonnei and 16 (38.1%) S. flexneri. All isolates were multidrug-resistant (resistance to more than 3 antibiotics). The occurrence of PMQR genes was as follows: qnrS (52.4%), qnrA and aac(6′)-Ib-cr (33.3%), and qnrB (19.0%). The prevalence in species was as follows: 61.5% and 37.5% (qnrS), 19.2% and 56.3% (qnrA), 38.5% and 25.0 (aac(6′)-Ib-cr), and 19.2% and 18.8% (qnrB) for S. sonnei and S. flexneri, respectively. The other PMQR genes were not detected. In total, 52.8% (28/53) of quinolone-susceptible and 64.3% (27/42) of quinolone-resistant isolates were biofilm producers. Biofilm formation was not significantly different between quinolone-resistant and quinolone-susceptible isolates (P-value = 0.299). Quinolone-resistant isolates showed a high genetic diversity according to the ERIC-PCR. Conclusion: It seems that qnrS, qnrA, and aac(6′)-Ib-cr play a significant role in the quinolone resistance among Shigella isolates in our region. Also the quinolone-resistant S. flexneri and S. sonnei isolates had a high genetic diversity. Hence, antibiotic therapy needs to be routinely revised based on the surveillance findings. [ABSTRACT FROM AUTHOR]

Background: Bacterial aggregation has been well described to occur in synovial fluid, but it is unknown if bacteria form aggregates in body fluids beyond the synovial fluid. Consequently, this translational study evaluated the ability to form bacterial aggregates in different pleural fluids. Methods: Four of the most common causes of thoracic empyema—Streptococcus mitis, Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa—were used here. The different pleural fluids included one transudative and two exudative pleural fluids. Twenty-four-well microwell plates were used to form the aggregates with the aid of an incubating shaker at different dynamic conditions (120 RPM, 30 RPM, and static). The aggregates were then visualized with SEM and evaluated for antibiotic resistance and the ability of tissue plasminogen activator (TPA) to dissolve the aggregates. Statistical comparisons were made between the different groups. Results: Bacterial aggregates formed at high shaking speeds in all pleural fluid types, but no aggregates were seen in TSB. When a low shaking speed (30 RPM) was used, only exudative pleural fluid with a high protein content formed aggregates. No aggregates formed under static conditions. Furthermore, there was a statistical difference in the CFU/mL of bacteria present after antibiotics were administered compared to bacteria with no antibiotics (p < 0.005) and when TPA plus antibiotics were administered compared to antibiotics alone (p < 0.005). Conclusions: This study shows that bacteria can form aggregates in pleural fluid and at dynamic conditions similar to those seen in vivo with thoracic empyema. Importantly, this study provides a pathophysiological underpinning for the reason why antibiotics alone have a limited utility in treating empyema. [ABSTRACT FROM AUTHOR]

Food‐related stresses such as heating and freezing may influence the biofilm formation ability of bacteria. This study aimed to investigate the main and interactive effects of food‐related stresses on the biofilm formation potential of Salmonella strains isolated from meat. Salmonella enteritidis, Salmonella typhi, and Salmonella typhimurium were subjected to osmotic, acid, heat, cold, and freezing stresses. The colorimetric microtiter plate method was used to measure the biofilm formation ability as a response to the stresses. Among the main effects, freezing time had the most significant effect on the biofilm formation responses of three Salmonella serovars. Freezing reduced the biofilm formation ability of Salmonella typhimurium and Salmonella enteritidis but increased that of Salmonella typhi (p < 0.05). Among the interaction effects, the most significant effect on the biofilm formation response of Salmonella typhi was the interaction between pH and heat, which had a negative effect on the biofilm formation response. In contrast, the interaction between osmotic pressure and cold stresses was the most significant interactive effect on the biofilm formation responses of Salmonella enteritidis and Salmonella typhimurium, which had an increasing effect. This study concluded that the food‐related stresses could change the biofilm formation capacity of Salmonella serotypes, and each serotype might show different biofilm formation abilities in response to different stresses. [ABSTRACT FROM AUTHOR]

The CRISPR/Cas13 nucleases have been widely documented for nucleic acid detection. Understanding the intricacies of CRISPR/Cas13's reaction components is pivotal for harnessing its full potential for biosensing applications. Herein, we report on the influence of CRISPR/Cas13a reaction components on its trans-cleavage activity and the development of an on-chip total internal reflection fluorescence microscopy (TIRFM)-powered RNA sensing system. We used SARS-CoV-2 synthetic RNA and pseudovirus as a model system. Our results show that optimizing Mg2+ concentration, reporter length, and crRNA combination significantly improves the detection sensitivity. Under optimized conditions, we detected 100 fM unamplified SARS-CoV-2 synthetic RNA using a microtiter plate reader. To further improve sensitivity and provide a new amplification-free RNA sensing toolbox, we developed a TIRFM-based amplification-free RNA sensing system. We were able to detect RNA down to 100 aM. Furthermore, the TIRM-based detection system developed in this study is 1000-fold more sensitive than the off-coverslip assay. The possible clinical applicability of the system was demonstrated by detecting SARS-CoV-2 pseudovirus RNA. Our proposed sensing system has the potential to detect any target RNA with slight modifications to the existing setup, providing a universal RNA detection platform. [ABSTRACT FROM AUTHOR]

Electrostatically actuated MEMS plate devices have many potential applications as micro-actuators and highly sensitive sensors. Bistability may occur in microplate devices and it refers to two stable configurations for a single value of actuating load. In this work, bistable behaviour of initially curved rectangular microplates, under the electrostatic and mechanical load actuation, has been investigated. In which detail investigation of bistability in load-deflection equilibrium paths and their associated characteristics, and later, resonance frequency behaviour in bistable regions have been carried out. For this, the governing differential equations of an initially curved rectangular plate have been developed using Kirchhoff's plate theory, including von Karman nonlinearity. Then, Galerkin's principle has been used to develop reduced order model of the governing partial differential equation of motion. To validate the results of reduced order model, we have carried out finite element analysis using a software COMSOL Multiphysics. We have observed qualitatively distinct behaviour in bistability characteristics of electrostatically and mechanically actuated microplates. We have also observed high sensitivity near bistability points and these points can be tuned by varying device parameters. This investigation could potentially help design bistable MEMS devices. [ABSTRACT FROM AUTHOR]

Zn2+ has a crucial role both in biology and the environment, while Pb2+ presents serious hazards in the same areas due to its toxicity, and the need for their analysis often exceeds available instrumental capacity. We report, herein, a new high-throughput optochemical screening method for Zn2+ and Pb2+ in various solutions. Moreover, we also introduced a new and generalizable three-step-microplate-modification technique, including plasma treating, linker-docking and photocatalytic copolymerization. The surface of a commercially available 96-well-cycloolefin-microplate was treated with atmospheric plasma, and then, the bottoms of the wells were covered by covalently attaching a methacrylate-containing linker-monolayer. Finally, the preactivated microplate wells were covalently functionalized by immobilizing bis(acridino)-crown ether-type sensor molecules, via photocatalytic copolymerization, to a polymethacrylate backbone. This sensing tool can be used in all microplate readers, is compatible with liquid handling platforms and provides an unprecedently fast monitoring (>1000 samples/hour, extrapolated from the time required for 96 measurements) of dissolved Zn2+ and Pb2+ among recent alternatives above the detection limits of 8.0 × 10−9 and 3.0 × 10−8 mol/L, respectively, while requiring a sample volume of only 20 µL. [ABSTRACT FROM AUTHOR]

Theoretical studies on the vibration of microcantilever beams in fluids, which are commonly used in micro- and nanoelectromechanical systems (MEMS/NEMS). When microcantilever beams are subjected to photo-thermal excitation, they show that the material properties such as the dynamic response and the one-dimensional temperature field will show significant differences from the macroscopic properties when the size appearance of the microbeam decreases to the scale below a dozen micrometers. In this paper, by correcting the scale constants of the beams, the photothermal vibration model of the microbeam is established using the physical neutral plane theory. The one-dimensional heat transfer equations and scale-corrected temperature field of the microcantilever beam under laser excitation are derived, which are solved by Galerkin’s method, based on the theory of thermoelasticity, the hydrodynamic model of the beams vibrating in incompressible liquids proposed by Sader et al. and the theory of Euler–Bernoulli beams. The equations governing the vibration of micro-cantilever beams corrected for scale effects in different fluids when subjected to photothermal excitation are obtained. The results show that the temperature field, resonant frequency, and quality factor of the microbeam will have a significant upward drift when the size of the microbeam is close to the scale parameter, and the scale effect has a non-negligible influence on the macroscopic performance parameters; the upward drift is gradually weakening when the thickness to scale ratio gradually increases. Finally, the property of the beam is almost the same as that of the theory when the thickness of the beam is 10 times the scale constant. The correction of the theory by the scale effect is insignificant. [ABSTRACT FROM AUTHOR]

Based on the consistent couple stress theory (CCST), we develop a size-dependent Hermitian C2 finite layer method (FLM) for carrying out the three-dimensional (3D) static bending analysis of a simply-supported, functionally graded (FG) piezoelectric microplate which is placed under closed-circuit surface conditions. The microplate of interest is assumed to be resting on a Winkler-Pasternak foundation and subjected to either sinusoidal or uniformly distributed electro-mechanical loads. By setting the material length scale parameter at zero and ignoring the piezoelectric and flexoelectric effects, we reduce the formulation of the Hermitian C2 FLM for analyzing FG piezoelectric microplates to that for analyzing FG piezoelectric macroplates and FG elastic microplates, respectively. The accuracy and the convergence rate of the Hermitian C2 FLM are assessed by comparing the solutions it produces with the exact and approximate 3D solutions of FG piezoelectric macroplates and FG elastic microplates reported in the literature. Because the Hermitian C2 FLM requires that the first-order and second-order derivatives of the primary variables must be continuous at each nodal plane, which in turn leads to their solutions converging rapidly and being able to obtain the accurate results of the electric and elastic variables induced in the microplates, especially for the transverse shear and normal stresses and the electric displacements. The effects of piezoelectricity, flexoelectricity, and the material length scale parameter on the deformations and stresses induced in the FG piezoelectric microplates are significant. A CCST-based Hermitian C2 finite layer method (FLM) is developed for analyzing functionally graded (FG) piezoelectric microplates. The current FLM can be reduced to that for analyzing FG elastic microplates by ignoring the piezoelectric and flexoelectric effects. The current FLM can be reduced to that for analyzing FG piezoelectric macroplates by setting the material length scale parameter at zero. Implementing the current FLM reveals that its solutions converge rapidly and are in excellent agreement with those obtained using the exact 3D models. The effects of piezoelectricity, flexoelectricity, and the material length scale parameter on the static bending behavior of FG piezoelectric microplates are significant. [ABSTRACT FROM AUTHOR]

In this study, a numerical model for electro-mechanical coupling analysis of geometrically nonlinear functionally graded piezoelectric shell is developed based on the weak form quadrature element method. Both piezoelectric and flexoelectric effects are introduced to establish the geometrically exact shell model with its constituent BaTiO3 and PZT-5H graded through the thickness. The electric potentials are assumed quadratic along the shell thickness to introduce the electric field for numerical implementation, while four different closed- or open-circuit conditions are considered. Four typical examples are presented to demonstrate the effectiveness of the present model and illustrate the influences of electro-mechanical couplings and functional graded materials on the responses of shells undergoing large displacements and rotations. This model is a feasible scheme for studying complex nonlinear behaviors of piezoelectric shells that might be helpful in devising piezoelectric shell-based nanoelectronics. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the performance of the rapid colorimetric polymyxin B microelution (RCPEm) in determining polymyxin B resistance directly from Enterobacterales-positive blood cultures. Methods: A set volume of positive blood culture bottles (diluted 1:10) was inoculated into a glucose-broth-phenol red solution (NP solution), where a polymyxin B disk was previously eluted (final concentration of 3 µg/mL). Test was read each 1 h for up to 4 h. Color change from red/orange to yellow indicated resistant isolates. Results were compared to the reference method, broth microdilution (BMD), performed from colonies grown on solid media from the same blood culture bottle. Results: One hundred fifty-two Enterobacterales-positive blood cultures were evaluated, 22.4% (34/152) of them resistant to polymyxin B (including 6.6% with borderline MICs). When performing directly from positive blood cultures (RCPEm-BC), specificity and sensitivity were 99.1% and 94.1%, respectively. Of note, 79.4% (27/34) of truly resistant isolates required 3 h of incubation, compared to the 18 ± 2 h incubation that microtiter plates of BMD demand before reading can be performed. Conclusions: RCPEm directly from blood cultures has great potential to be part of the routine of clinical microbiology laboratories to establish polymyxin B susceptibility, impacting outcome of patients with bloodstream infections caused by carbapenem-resistant Enterobacterales. [ABSTRACT FROM AUTHOR]

The classical pathway of the complement system is activated by the binding of C1q in the C1 complex to the target activator, including immune complexes. Factor H is regarded as the key downregulatory protein of the complement alternative pathway. However, both C1q and factor H bind to target surfaces via charge distribution patterns. For a few targets, C1q and factor H compete for binding to common or overlapping sites. Factor H, therefore, can effectively regulate the classical pathway activation through such targets, in addition to its previously characterized role in the alternative pathway. Both C1q and factor H are known to recognize foreign or altered-self materials, e.g., bacteria, viruses, and apoptotic/necrotic cells. Clots, formed by the coagulation system, are an example of altered self. Factor H is present abundantly in platelets and is a well-known substrate for FXIIIa. Here, we investigated whether clots activate the complement classical pathway and whether this is regulated by factor H. We show here that both C1q and factor H bind to the fibrin formed in microtiter plates and the fibrin clots formed under in vitro physiological conditions. Both C1q and factor H become covalently bound to fibrin clots, and this is mediated via FXIIIa. We also show that fibrin clots activate the classical pathway of complement, as demonstrated by C4 consumption and membrane attack complex detection assays. Thus, factor H downregulates the activation of the classical pathway induced by fibrin clots. These results elucidate the intricate molecular mechanisms through which the complement and coagulation pathways intersect and have regulatory consequences. [ABSTRACT FROM AUTHOR]

Anhydrous guanine (AG) crystals are widely applied in organisms due to their excellent optical properties. However, the influence of biomolecules on the biomineralization process of guanine crystals in organisms remains unexplored. In this study, mixed proteins from the silver film of carp fish scales were extracted and were used as a model system to elucidate the effect of biomolecules on guanine crystallization for the first time. The mixed proteins were enriched with amino acids such as Asp, Glu, Leu and Lys. Elongated hexagonal microplates of α-form AG (α-AG) mixed with a small amount of β-form AG (β-AG) mainly exposing the (100) plane were obtained in the presence of the mixed proteins under mild conditions while irregular particles were formed in the absence of proteins, indicating that the extracted mixed proteins have a strong influence on the formation of AG microplates exposing the (100) plane. It is found that the proteins not only adsorb on the surface but also occluded into the AG crystals. We also find that guanine analogues have profound synergetic effects on the morphology and polymorphs of guanine in the in vitro synthetic system. The obtained α-AG exhibit superior optical properties such as high reflectivity, strong depolarization and pearlescent luster. This in vitro synthesis work shows clearly the strong influence of biomolecules for the biomineralization process of guanine crystals in organisms. [ABSTRACT FROM AUTHOR]

A porous microplate embedded with two nanocomposite piezoelectric layers is investigated in the current work. All three layers are functionally graded and completely attached to each other, and the microstructure lies on a bi-parameter elastic foundation that withstands shear and normal forces simultaneously. Also, an external voltage is subjected to the piezoelectric patches. The mentioned patches are reinforced with carbon nanotubes to enhance their electro-mechanical performance. A higher-order shear deformation theory and von Karman's assumptions are hired to demonstrate the kinematic relations. Next, applying Hamilton's principle and variational technique, the governing motion equations are derived with the help of the modified couple stress theory to capture the scale influence. To solve the system of differential equations, a closed-form Navier method is employed, and by ensuring the correctness of the results, then it turns to investigate the impact of different factors including porosity percentage and also pores' distribution patterns, nanotubes dispersion patterns, and other important factors on the natural frequencies of the model. Obtained results show that symmetric and uniform porosity distributions have the maximum and minimum amounts of natural frequencies. Moreover, the maximum difference between natural frequencies of three different porosity distribution occurs in e0 = 0.95 and is approximately 32%. The current study results may consider to design and produce smart structures and devices with improved performance. [ABSTRACT FROM AUTHOR]

This study deals with the size-dependent nonlinear vibration and dynamic responses of microplates reinforced by the porous Graphene Platelets (GPL) nanofillers under the thermal environment. The heat conduction is taken into account by the graphene platelets dispersion and porosity distribution, and the nonlinear temperature rise is assumed to be varied in thickness. To pursue the research purpose, the modified couple stress and nonlocal theories with the geometrically nonlinear analysis based on the higher-order shear strains are integrated to describe the mechanical characteristics of microplates. Three GPL distributions in conjunction with three porosity patterns dispersed along the thickness cause the nonlinear temperature profiles to vary with the relative density and porosity. The nonclassical motion equilibrium equations are established with the aid of the virtual work's principle, the Halpin–Tsai micromechanical modeling, and the new nonlinear temperature profiles solved by heat conduction. Moreover, the improved iterative method produced into the Bézier extraction approach scrutinizes the microplate's size-dependent thermal frequency-deflection responses. Consequently, the desired mechanical properties and the structural characteristics of the GPL intact and hearted cutout microplates have been efficiently enhanced by incorporating the porosity coefficient, GPL dispersion, negative GPL thermal expansion, and length scale parameter, particularly under nonlinear temperature conditions. [ABSTRACT FROM AUTHOR]

The primary focus of the present contribution is to develop a new system of differential equations describing the nonlocal thermoelasticity theory. The problem deals with the thermoelastic interaction in a nonhomogeneous thermoelastic layer induced by absorbing penetrating laser radiation throughout its volume. The heat conduction equation has been formulated in the context of memory dependent three-phase lag model. The surfaces of the layer are thermally insulated and free of traction. Employing the integral Laplace transform technique, the solutions of the field quantities have been achieved in the transformed domain. The corresponding solutions in the space–time domain have been derived using the numerical inversion of the Laplace transform by Riemann-sum approximation technique. The numerical estimates of the field quantities have been depicted graphically to address the effects of nonlocality and memory effects on the temperature profile, displacement and stress components. The effect of the delay time, nonhomogeneity and various choices of linear and nonlinear kernel functions in the heat transport law have also been reported. [ABSTRACT FROM AUTHOR]

Considering the anisotropic characteristics of carbon fiber reinforced composites, the couple stress theory was modified, and the loading model of microscale Mindlin laminates in a hygrothermal environment was established. The material scale parameters affected by the environment were introduced, and the governing equations and boundary conditions were solved by using the principle of virtual work. Taking the four-sided simply supported square laminate by the orthogonal layer as an example, the displacement function of the Navier solution method was set to calculate the critical loads of the Mindlin laminates in a hygrothermal environment. The results show that the critical loads of Mindlin micro-laminate are greater than those of classical macro-theory under unidirectional axial compressive loads. The scale effect strengthens with the increase of material scale parameters, and the scale effect becomes more obvious with an increase in temperature change and hygroscopic concentration. The scale effect gradually disappears with the increase of the geometric parameters of the laminate, and the model degenerates into a macroscopic model. [ABSTRACT FROM AUTHOR]

Copyright of Mugla Journal of Science & Technology is the property of Mugla Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study was undertaken on 164 bovine milk samples (cow = 113 and Buffalo = 51) collected from various dairy farms in and around Rewa (Madhya Pradesh, India) and only 24 samples (6.83%) were found to be positive for mastitis when screened through California Mastitis Test (CMT). The prevalence of subclinical mastitis in cattle was 21%. All 17 isolates were phenotypically characterized by mannitol fermentation, biochemical tests (acetoin production by Voges-Proskauer test), beta-galactosidase test susceptibility to novobiocin (5 µg disk), resistance to polymyxin B (300 µg disk). We also observed the biofilm formation ability of all the Staphylococcus aureus strains (n=17) by Congo Red Agar (CRA), Microtiter plate (using crystal violet), and light microscopy method, 90% sensitivity was seen through microtiter plate method. Antibiofilm activity of garlic oil was undertaken on positive isolates (3%, 2%, and 1% concentration) along with positive and negative control in every microtiter plate assay. Maximum inhibition was observed at 3% concentration with O.D values ranging from 0.021±0.007 to 0.291 ± 0.005 in all the samples with percent inhibition (50 to 60%). Multi-drug resistance profiles of biofilm-producing isolates were also undertaken against polymyxin, novobiocin, tetracyclines, cotrimoxazole, clindamycin, cefoxitin, and cefoperazone. Eighty-two (82) percent of isolates showed resistance against polymyxin, 52% against novobiocin and erythromycin, and all the isolates showed 100% sensitivity against tetracyclines and cefoxitin. [ABSTRACT FROM AUTHOR]

A general strategy is proposed to solve the problem of efficient and controlled removal of droplets from solid surfaces. Droplet departure size on magnetic responsive polydimethylsiloxane superhydrophobic microplates (MPSM) was significantly reduced compared to the static structure, resulting in a 60% increase in the efficiency of fog collection at 15 min to meet a wide range of fields. [Display omitted] Efficient removal of droplets from solid surfaces is significant in various fields, including fog collection and condensation heat transfer. However, droplets removal on common surfaces with static structures often occurs passively, which limits the possibility of increasing removal efficiency and lacks intelligent controllability. In this paper, an active strategy based on extrusion ejection is proposed and demonstrated on the magnetic responsive polydimethylsiloxane (PDMS) superhydrophobic microplates (MPSM). The MPSM can reversibly transit between the upright and tilted state as the external magnetic field is alternately applied and removed. Under the magnetic field, the direction and trajectories of droplets departure can be intelligently controlled, demonstrating excellent controllability. More importantly, compared with the static structure where the droplet must reach a certain size before departure, droplets can be ejected at smaller sizes as the MPSM is tilted. These advantages are of great significance in many fields, such as a highly efficient fog harvesting system. This strategy of extrusion ejection based on dynamic surface structure control reported in this work may provide fresh ideas for efficient droplet manipulation. [ABSTRACT FROM AUTHOR]

Background: Side effects associated with antimicrobial drugs, as well as their high cost, have prompted a search for low-cost herbal medicinal substances with fewer side effects. These substances can be used as supplements to medicine or to strengthen their effects. The current study investigated the effect of oleuropein on the inhibition of fungal and bacterial biofilm in-vitro and at the molecular level. Materials and methods: In this experimental study, antimicrobial properties were evaluated using microbroth dilution method. The effect of oleuropein on the formation and eradication of biofilm was assessed on 96-well flat bottom microtiter plates and their effects were observed through scanning electron microscopy (SEM). Its effect on key genes (Hwp1, Als3, Epa1, Epa6, LuxS, Pfs) involved in biofilm formation was investigated using the quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) method. Results: The minimum inhibitory concentration (MIC) and minimum fungicidal/bactericidal concentration (MFC/MBC) for oleuropein were found to be 65 mg/ml and 130 mg/ml, respectively. Oleuropein significantly inhibited biofilm formation at MIC/2 (32.5 mg/ml), MIC/4 (16.25 mg/ml), MIC/8 (8.125 mg/ml) and MIC/16 (4.062 mg/ml) (p < 0.0001). The anti-biofilm effect of oleuropein was confirmed by SEM. RT-qPCR indicated significant down regulation of expression genes involved in biofilm formation in Candida albicans (Hwp1, Als3) and Candida glabrata (Epa1, Epa6) as well as Escherichia coli (LuxS, Pfs) genes after culture with a MIC/2 of oleuropein (p < 0.0001). Conclusions: The results indicate that oleuropein has antifungal and antibacterial properties that enable it to inhibit or destroy the formation of fungal and bacterial biofilm. [ABSTRACT FROM AUTHOR]

Proteus mirabilis, a urease-producing bacterium, is a frequent culprit in urinary tract infections (UTIs). Most Gram-negative bacteria are characterized by their ability to produce biofilms outside their bodies, which usually adhere to solid surfaces. Biofilm formation is a significant concern in UTIs as it can hinder the efficacy of antibiotic treatment. The connection between antibiotic susceptibility and biofilm development was examined in this study in P. mirabilis isolates from UTI patients to identify the profiles of antibiotic susceptibility of P. mirabilis, assess biofilm formation ability among these isolates, and explore potential links between antibiotic resistance and biofilm production. The urine samples of 300 UTI patients from August to November 2023 were taken in Hilla city, Iraq. P. mirabilis isolates were identified and subjected to disc diffusion testing for antibiotic susceptibility and microtiter plate assays for biofilm formation. The results showed that all 67 P. mirabilis isolates harbored the urease gene and exhibited the highest resistance rates to trimethoprim (43.28%), chloramphenicol (31.34%), vancomycin (41.79%), and nitrofurantoin (29.85%), while all isolates were imipenem susceptible. Resistance to other antibiotics ranged from 2.9% to 13.43%. Importantly, 21 (31.34%) isolates were multidrug-resistant (MDR). All isolates formed biofilms with 23 (34.3%) demonstrating strong biofilm production, significantly associated with MDR isolates. This study revealed a substantial proportion of P. mirabilis isolates from UTI patients displaying the development of biofilms and carrying antibiotic resistance, especially among MDR isolates. These findings underscored the crucial need for continuous antibiotic resistance surveillance and novel strategies for preventing and treating UTIs caused by P. mirabilis. [ABSTRACT FROM AUTHOR]

In this communication, it is mathematically proved that the modified couple stress theory-based stability trend (buckling-post-buckling) of the size-dependent porous functionally graded (metal-ceramic) shear deformable microplates with fully simply supported edges was wrongly predicted in the aforementioned paper. [ABSTRACT FROM AUTHOR]

Ice nucleation particles play a crucial role in atmospheric processes; for example, they can trigger ice formation in clouds and thus influence their lifetime and optical properties. The quantification and characterization of these particles require reliable and precise measurement techniques. In this publication, we present a novel droplet freezing instrument to measure the immersion freezing of biotic and abiotic ice-nucleating particles within the temperature range of 0 to - 25 °C. Immersion freezing of the samples is investigated using 384-well PCR plates with a sample volume of 30 µL. Nucleation events are detected with high precision using a thermal camera that records the increase in infrared emission due to the latent heat release. To maximize the thermal contact between the PCR plate and the surrounding cooling unit, we use a gallium bath as a mount for the PCR plate. The instrument was validated relative to a calibrated temperature standard and through reproducibility measurements employing the same suspension. We find that the combination of good thermal connectivity and precise temperature recording enables accurate (± 0.81 °C at - 10 °C) and reproducible (± 0.20 °C) detection of the nucleation temperatures. Consequently, the results that are produced using the MICROtiter-Plate-based instrument for Ice Nucleation detection in GalliUm with an INfrared camera (micro-PINGUIN) are of good quality and the instrument can be used to study the immersion freezing of various ice-nucleating particles. For comparison with already existing instruments, Snomax® (hereafter Snomax) and illite NX suspensions are measured with the new ice nucleation instrument, micro-PINGUIN. Further, we investigated the reproducibility of experiments using Snomax suspensions and found poor reproducibility when suspensions were prepared freshly even if the same batch of Snomax is used. This could be attributed to substrate heterogeneity, aging effects, and dilution errors. The reproducibility of the measurements is greatly improved for Snomax suspensions that are prepared in advance and stored frozen in aliquots. Thus, we suggest the use of suspensions frozen in aliquots for further reproducibility measurements and intercomparison studies. [ABSTRACT FROM AUTHOR]

The remarkable optoelectronic features of halide perovskite promote their potential applications in semiconductor devices beyond solar cells, which require high-quality single crystals with controlled defect levels. Herein, we investigated the synthesis mechanism of chemical vapor deposited single-crystalline all-inorganic perovskite microplates (MPs), and reported a defect-modulated photocurrent which is closely related to the growth sequence of the MPs. The MP synthesis initiates from island-like nano-disks, and subsequently transits to a layer-by-layer fashion, resulting in a defect-rich area at the center of the MPs. At elevated temperatures, these central defects may be thermally activated and become highly mobile, leading to photoluminescence quenching and degression of local and overall optoelectronic attributes, as evidenced by the spatial resolved optical and electrical scanning probe microscopy. Overall, this work shines light on the formation, proliferation and dynamics of defects in perovskites, and offers guidance for preparation of high-quality perovskites micro-crystals for functional semiconductor devices with high temperature stability. [ABSTRACT FROM AUTHOR]

Based on the hyperbolic tangent parabola mixed shear deformation theory, the paper studied the sound radiation and the sound insulation of the functionally graded (FG) sandwich microplates under thermal-electric effects. The sandwich plate is composed of piezoelectric skin layers and FGM core layer. By using Hamilton's principle, a size-dependent model considering the thermal-piezoelectric effects are established. The acoustic response and sound insulation are calculated with Rayleigh integral and solid-fluid coupling conditions. The accuracy of the presented method is verified by the numerical simulations. Then the effects of various parameters on the vibro-acoustic characteristics are analyzed and discussed. Numerical results show that the temperature variations, the length scale parameter to thickness ratio and the gradient index have great impacts on the FG sandwich microplates. [ABSTRACT FROM AUTHOR]

Nanotechnology has gained much attention, especially in medical research, but its rapid development and the widespread use of nanoproducts raise questions about the ecotoxicity of these materials. In this work we studied the toxicity induced by nano Fe3O4 in a model organism, Artermia salina (A. salina) in an aquatic environment. These nanoparticles were synthesized by the microwave-assisted hydrothermal method. The methodology was a completely randomized experimental design and had 8 treatments which were: filtered and autoclaved seawater, CuSO4, 10 mg/L, 100 mg/L, 250 mg/L, 500 mg/L, 1000 mg/L and 10000 mg/L of Fe3O4, each with 3 replicates. The experimental units were composed of 100 uL of each treatment and 10 instar III nauplii in a 24- well microplate. After 24 hours, the number of dead larvae and LC50 were determined using the statistical program R free version. As a result, the X-ray diffractogram indicated the formation of Fe3O4 with a crystallite size of 10.1nm; FT-IR spectroscopy confirmed the pure phase of the material with the presence of its characteristic bands. The LC50 had a value of 5356.76 mg/L of Fe3O4 at 24 hours of exposure to A. salina. In conclusion, Fe3O4 nanoparticles have a toxic effect causing larval death at concentrations above 5356.76 mg/L. [ABSTRACT FROM AUTHOR]

An efficient and scalable method to prepare oligolactic acid stereocomplex microplates (SC‐OLA‐MPs) is developed. Oligolactic acid was firstly synthesized via the melt polycondensation of lactic acid. Then, the oligo (L‐lactic acid) and oligo (D‐lactic acid) were crystallized with a mixture of dichloromethane and acetone, and consequently the stereocomplex microparticles were obtained in the form of circular microplates with a diameter of approximately 2 μm. As an eco‐friendly nucleating agent, SC‐OLA‐MPs were introduced into poly (L‐lactic acid) (PLLA) via melt blending. The nonisothermal and isothermal crystallization of the SC‐OLA‐MPs/PLLA composites were investigated, and the crystal morphology and heterogeneous nucleation phenomena during the isothermal crystallization process were photographed with POM. SC‐OLA‐MPs show excellent nucleating effects on PLLA crystallization. With the incorporation of 10% SC‐OLA‐MPs, the crystallization half‐time of the SC‐OLA‐MPs/PLLA composite decreased from 7.18 to 0.45 min at 100°C, compared to the neat PLLA. Through a short‐time molding procedure, the thermal deformation temperature of PLLA is improved by the addition of SC‐OLA‐MPs. Highlights: Polylactic acid stereocomplex microplates were fabricated by solution crystallization.This method is easy and scalable.This microplate is an effective nucleating agent for PLLA. [ABSTRACT FROM AUTHOR]

Lanthanide-based microlasers have attracted considerable attention owing to their large anti-Stokes shifts, multiple emission bands, and narrow linewidths. Various applications of microlasers, such as optical communication, optical storage, and polarization imaging, require selecting the appropriate laser polarization mode and remote control of the laser properties. Here, we propose a unique plasmon-assisted method for the mode selection and remote control of microlasing using a lanthanide-based microcavity coupled with surface plasmon polaritons (SPPs) that propagate on a silver microplate. With this method, the transverse electrical (TE) mode of microlasers can be easily separated from the transverse magnetic (TM) mode. Because the SPPs excited on the silver microplate only support TM mode propagation, the reserved TE mode is resonance-enhanced in the microcavity and amplified by the local electromagnetic field. Meanwhile, lasing-mode splitting can be observed under the near-field excitation of SPPs due to the coherent coupling between the microcavity and mirror microcavity modes. Benefiting from the long-distance propagation characteristics of tens of micrometers of SPPs on a silver microplate, remote excitation and control of upconversion microlasing can also be realized. These plasmon-assisted polarization mode-optional and remote-controllable upconversion microlasers have promising prospects in on-chip optoelectronic devices, encrypted optical information transmission, and high-precision sensors. [ABSTRACT FROM AUTHOR]

Automated high-throughput liquid handling operations in biolabs necessitate miniaturised and automatised equipment for effective space utilisation and system integration. This paper presents a thermal segment microwell plate control unit designed for enhanced microwell-based experimentation in liquid handling setups. The development of this device stems from the need to move towards geometry standardization and system integration of automated lab equipment. It incorporates features based on Smart Sensor and Sensor 4.0 concepts. An enzymatic activity assay is implemented with the developed device on a liquid handling station, allowing fast characterisation via a high-throughput approach. The device outperforms other comparable devices in certain metrics based on automated liquid handling requirements and addresses the needs of future biolabs in automation, especially in highthroughput screening. [ABSTRACT FROM AUTHOR]

Hexagonal TiO2/SiO2 Porous Microplates have been successfully synthesized by incorporation of Ti precursors into SiO2 synthesized from Si precursors in a gelatin-CTAB mixture via the hydrothermal method. The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDX, nitrogen adsorption-desorption and Fourier transform infrared spectroscopy (FTIR). The sample has a surface area of 735 m²/g, pore volume of 0.67 cc/g, and pore diameter of 3.2 nm, according to the results of the characterization of hexagonal TiO2/SiO2 porous microplates. The transformation of SiO2 microspheres into hexagonal TiO2/SiO2 porous microplates is revealed by a microparticle size increase of 84% and the transition of Si-O bonds into Ti-O and Si-O as measured by FTIR. The photocatalytic activity of hexagonal TiO2/SiO2 porous microplates resulted in 81.15% photodegradation of methylene blue under UV light irradiation within 60 min, which was 21% better than SiO2. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to determine the influence of environmental pH on production of biofilms and virulence genes expression in Pseudomonas aeruginosa. Design/methodology/approach: Among 303 clinical and environmental samples 109 (61 + 48) isolates were identified as clinical and environmental P. aeruginosa isolates, respectively. Clinical samples were obtained from patients in the Al-Yarmouk hospital in Baghdad city, Iraq. Waste water from Al-Yarmouk hospital was used from site before treatment unit to collect environmental samples. The ability of producing biofilm at various pH levels was examined by microtiter plate and the prevalence of Alg D, Psl A and Pel A was determined by quantitative real time-polymerase chain reaction (qRT-PCR). Findings: This study showed that the ability of clinical and environmental isolates to biofilm development was observed in 86.9% and 85.42% of clinical and environmental isolates, respectively. As well as, the environmental P. aeruginosa isolates showed the highest biofilm production at pH 7. Clinical isolates showed the highest genes expression of Alg D, Psl A and Pel A as compared to environmental isolates with pH change. In general, both clinical and environmental isolates formed biofilm and carried AlgD, PslA and PelA genes. Also, alkaline pH was favored for biofilm production. Originality/value: There are very few studies done to find out the influence of environmental pH on production of biofilms and virulence genes expression in Pseudomonas aeruginosa. This study is unique as it has highlighted the influence of environmental pH on the ability of clinical and environmental isolates to biofilm development and genes expression. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the College Of Basic Education is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)