Absorption Changes Research Articles

Influence of laser absorptivity of CuCr0.8 substrate surface state on the characteristics of laser directed energy deposition inconel 718 single track

An effective method for fabricating copper-nickel bimetallic liquid rocket engine thrust chambers involves utilizing laser directed energy deposition (LDED) technology. However, the state of the substrate surface significantly impacts the LDED process. This study investigates the effects of various substrate treatments on LDED single tracks, using CuCr0.8 high-copper alloy as the substrate and Inconel 718 as the deposition material. The treatments include polishing, sandblasting, laser etching, and cold spraying. Substrate surface roughness, laser absorptivity, molten pool morphology, and microstructure were characterized, and the mechanisms of laser absorptivity change and the different LDED processes were analyzed. The results indicate that the laser-etched surface exhibits the worst surface roughness (Ra 15.20 ± 0.60 μm), the highest laser absorptivity(80.70% at 1080 nm wavelength), the largest deposition width (947.33 ± 29.85 μm), and the maximum number of fine grains among the four substrates. Additionally, the cold-sprayed surface shows the largest deposition depth (237.33 ± 39.04 μm), the minimum number of fine grains and a higher laser absorptivity (66.20% at 1080 nm wavelength). In situ observations of molten pool formation and flow during LDED was conducted using an in situ high-speed high-resolution imaging system. The mechanisms underlying the alteration in laser absorptivity primarily involve the "trapped light" effect and modifications to the surface material. This research is significant as it provides foundational insights for laser processing of highly reflective materials, offering important theoretical and practical implications for engineering applications.

Bariatric Surgery and Metabolic Status.

Background and Objectives: Obesity is associated with numerous co-morbidities, including dyslipidemia, insulin resistance and diabetes mellitus. Bariatric surgery is the mainstay of treatment for obesity as the only method with confirmed long-term effects in weight reduction and the remission of comorbidities. Postoperative recommendations leading to changes in dietary habits and changes in digestion and absorption in the gastrointestinal tract after bariatric surgery may additionally influence the levels of laboratory parameters that reflect the metabolic and nutritional status. The purpose of the study was to analyze the possible influence of changes in dietary habits after bariatric surgery on those laboratory results that reflect the metabolic and nutritional status. Materials and Methods: This was a retrospective study of 88 patients with a history of bariatric surgery. Data were gathered from before the surgery and at 6 months after the surgery and included diet structure and selected laboratory parameters reflecting the metabolic and nutritional status, i.e., levels of fasting glucose, glycated hemoglobin, cholesterol, low- and high-density lipoproteins, triglycerides, alanine and aspartate aminotransferases, proteins, ferrum, ferritin, vitamin B12, folic acid, vitamin D and calcium, the red blood cell count and the hematocrit. Results: Postoperative festive glucose levels were reduced by 14% and were more significant in patients after Roux-en-Y gastric bypass. There was an increase of 22% in concentrations of high-density lipoproteins. Triglyceride concentrations were reduced by 32%. Aminotransferase levels decreased by 43% for alanine aminotransferase and by 14% for aspartate aminotransferase. Among the changes in dietary habits, post-bariatric patients had a reduced consumption of red meat and an increased consumption of fish, milk and dairy products and wholegrain products. Vitamin D and ferrum levels were higher after the surgery, whereas vitamin B12 and folic acid levels remained unchanged. Conclusions: Improved dietary habits of patients after bariatric surgery may lead to changes in laboratory parameters that reflect the ameliorated metabolic and nutritional status of patients after bariatric surgery.

Development of a high throughput cytochrome P450 ligand-binding assay

Human cytochrome P450 enzymes are membrane-embedded monooxygenases responsible for xenobiotic metabolism, steroidogenesis, fatty acid metabolism, and vitamin metabolism. Their active sites can accommodate diverse small molecules and understanding these interactions is key to decoding enzymatic functionality and designing drugs. The most common method for characterizing small molecule binding is quantifying absorbance changes that typically occur when ligands enter the active site near the heme iron. Traditionally, such titrations are monitored by a spectrophotometer, requiring significant manual time, protein, and increasing solvents. This assay was adapted for semi-automated high throughput screening, increasing throughput 50-fold while requiring less protein and keeping solvent concentrations constant. This 384-well assay was validated for both type I and II shifts typically observed for substrates and heme-coordinating inhibitors, respectively. This assay was used to screen a library of ∼100 diverse imidazole-containing compounds which can coordinate with the heme iron if compatible with the overall active site. Three human cytochrome P450 enzymes were screened: drug-metabolizing CYP2A6 and CYP2D6 and sterol-metabolizing CYP8B1. Each bound different sets of imidazole compounds with varying Kd values, providing a unique binding fingerprint. As a final validation, the Kd values were used to generate pharmacophores to compare to experimental X-ray structures. Applications for the high-throughput assay include the following: 1) facilitating generation of pharmacophores for enzymes where structures are not available, 2) screening to identify ligands for P450 orphans, 3) screening for inhibitors of P450s drug targets, 4) screening potential new drugs to avoid and/or control P450 metabolism, and 5) efficient validation of computational ligand binding predictions.

PK-PD relationship of poorly absorbable active ingredients from traditional Chinese medicines explaining by metabolic enzyme of gut microbiota: A case study of Dehydrocorydaline

Many active ingredients in traditional Chinese medicines generally have the characteristic of poor oral absorption but definite efficacy. It is necessary to establish a comprehensive technical system to explain the “PK-PD relationship” of them. Dehydrocorydaline (DHC), the quality control component in the Chinese patent drug “Kedaling Tablets”, has poor oral absorption but clear efficacy for coronary heart disease. Using DHC as a model drug, the changes in absorption and pharmacological effects of DHC in rats before and after inhibiting nitroreductase (NR) from gut microbiota were studied. The results showed that after inhibiting of NR activity, the plasma concentration of DHC in rats was decreased, the serum level of total cholesterol, triglyceride and low-density lipoprotein cholesterol were significantly increased. The levels of tumor necrosis factor-α, interleukin-1β, hypersensitive C-reactive protein, intercellular cell adhesion molecule-1 and Monocyte chemoattractant protein-1 were significantly increased, and pathological sections also showed that the efficacy of DHC decreased after inhibiting the activity of NR. We further investigated the drug metabolism of DHC under NR and found that DHC was metabolized into a hydrogenated metabolite, which may have stronger membrane permeability. In summary, NR may mediate the absorption degree and efficacy of DHC in vivo by metabolizing DHC into absorbable metabolite.

Evaluation of the Physical Compatibility of Intravenous Methocarbamol in Lactated Ringer’s, 0.45% Normal Saline, and Plasma-Lyte A

Background: The need to determine physical compatibility of intravenous admixtures is directly related to patient safety and patient outcomes. While the provision of multi-modal analgesic strategies has increased over the past decade, a paucity of data exists regarding physical compatibility of select medications. Objectives: To evaluate the physical compatibility of methocarbamol in Lactated Ringer’s (LR), 0.45% normal saline (0.45% NaCl), and Plasma-Lyte A (PLA) at concentrations of 4, 10, and 20 mg/mL. Methods: Admixtures were prepared and evaluated using previously validated methods under a laminar flow hood using aseptic technique. Samples were prepared in a triplicate manner, 3 mL aliquots were placed into polymethyl methacrylate cuvettes for evaluation at time points 0, 1, 5, 8, and 24 hours. Visual inspection of samples included assignment of a number: 0—no precipitation, 1—trace evidence of precipitation, 2—slight haze, 3—medium haze, and 4—heavy precipitation. Any evidence of precipitation was considered significant. A variable wavelength spectrophotometer set at 547 nanometers was used to measure absorbance. A change in absorbance of ±0.010 was considered significant. A change in pH of ±0.1 was considered significant. Results: No significant changes occurred relating to visual inspection or absorbance across all concentrations and time points for LR; however, there was a significant change in pH across all concentrations at hour 5. In 0.45% NaCl and PLA, no remarkable changes occurred across all concentrations and time points regarding visual observation, spectrophotometric absorbance, and pH analysis. Conclusions: Methocarbamol at concentrations of 4, 10, and 20 mg/mL is physically compatible for up to 1 hour in LR. Methocarbamol is physically compatible in 0.45% NaCl and PLA for up to 24 hours. Chemical stability tests are warranted to confirm these findings.

Multiple impact resistance and microstructure of hybrid fiber-reinforced fly ash/slag-based geopolymers after exposure to elevated temperatures

Engineered geopolymer composites (EGC) have garnered significant attention from researchers as a new environmentally friendly building material with superior tensile properties, impact resistance, and high-temperature resistance. This study focuses on the investigation of the dynamic mechanical properties of a hybrid fiber reinforced lightweight EGC containing ceramsite (LW-EGC) after exposure to elevated temperatures and multiple impacts. The effects of temperature, steel fiber content, and ceramsite types were taken into consideration. The analysis encompassed multiple impact stress-strain curves, dynamic peak stress and strain evolution, energy absorption, damage evolution, damage morphology, and microstructure changes following exposure to elevated temperatures. The experimental results revealed a significant decrease in the number of impacts endured by LW-EGC-M as the temperature increased. After 200 °C, the LW-EGC-M experienced 15 impacts, while after 800 °C, it only endured 2 impacts. Both cumulative energy absorption and cumulative damage of LW-EGC exhibited an exponential growth pattern with an increasing number of impacts. Microstructural analysis unveiled the emergence of a new nepheline phase after exposure to elevated temperatures, while the calcite in the matrix demonstrated gradual decomposition. Moreover, elevated temperatures led to a decreased Si/Al ratio in the matrix. The complete melting of PVA fibers after exposure to elevated temperatures resulted in the production of numerous interconnected pores in the matrix, leading to a decline in the mechanical strength of LW-EGC. This phenomenon also contributed to the reduction of internal pore pressures and the release of local vapor pressure generated by elevated temperatures.

Solvatochromic Dyes Track a Homeopathic Preparation through Water-Stream Systems in a Program to Control Tick Infestation at a Wild Animal Rehabilitation Center in Brazil.

In 2021, the area of CRAS (Centro de Reabilitação de Animais Selvagens - Wild Animal Rehabilitation Center), located in a state park in Campo Grande City, Mato Grosso do Sul, Brazil, was suffering from a tick infestation affecting wild animals that inhabit the area and humans that visited its trails. Following a formal technical-scientific cooperation agreement between IMASUL, an institute for the environment in Mato Grosso do Sul state, and SIGO Homeopatia, a formulated homeopathic complex (Formula Parques Urbanos, FPU) was designed and prepared specifically to treat the animals. This environmental intervention used specially designed slow-release water biodegradable devices. Tracking the FPU signal in water was necessary to monitor and manage the intervention. Our aims were (1) to evaluate, among six previously standardized solvatochromic dyes, which would serve as a marker for the homeopathic complex under study; and (2) to evaluate whether the chosen solvatochromic dye could map the propagation of the homeopathic complex activity throughout the stream system from water samples harvested at different locations over time. Water samples were harvested from each point at different times, filtered, frozen, and sent to the laboratory, where they were prepared at 1cH potency for analysis using 30% ethanol as the vehicle. Solvatochromic dyes were used to analyze the samples since they alter their absorbance when in contact with homeopathic potencies. Of the six dyes tested, Coumarin 7 was found to be the most suitable for tracking the FPU complex. A static and average unidirectional magnetic field of 2,400 Gauss (240 mT), generated by a neodymium magnet, was applied to the samples immediately before reading. There were significant differences in the delta absorbance of dyes when adding treated/potentized water samples, making it possible to map the propagation of the FPU signal throughout the park over time. The signals were identifiable at the same point 1 minute and 32 days after the insertion of the device into the water. These signals were also identifiable after 75 minutes and 8 days at a point far from the insertion place. Coumarin 7 was the best marker for the homeopathic complex (FPU) used to treat the wild animals living in the park. The microplates/enzyme-linked immunosorbent assay reader method and the application of a magnetic field to samples were shown to be effective in tracing homeopathic signals by changes in dye absorbance (p ≤ 0.02) in a real-life situation, with large volumes of water, involving many environmental variables, and over large distances.

Simulation study of multi-layer titanium nitride nanodisk broadband solar absorber and thermal emitter

Solar energy has always been a kind of energy with large reserves and wide application. It is well utilized through solar absorbers. In our study, the finite difference time domain method (FDTD) is used to simulate the absorber composed of refractory metal materials, and its absorption performance and thermal emission performance are obtained. The ultra-wide band of 200 nm–3000 nm reaches 95.93% absorption efficiency, of which the bandwidth absorption efficiency of 2533 nm (200 nm–2733 nm) is greater than 90%. The absorption efficiency in the whole spectrum range (200 nm–2733 nm) is 97.17% on average. The multilayer nanodisk structure of the absorber allows it to undergo strong surface plasmon resonance and near-field coupling when irradiated by incident light. The thermal emission performance of the absorber enables it to also be applied to the thermal emitter. The thermal emission efficiency of 95.37% can be achieved at a high temperature of up to 1500 K. Moreover, the changes of polarization and incident angle do not cause significant changes in absorption. Under the gradual change of polarization angle (0°–90°), the absorption spectrum maintains a high degree of consistency. As the incident angle increases from 0° to 60°, there is still 85% absorption efficiency. The high absorption efficiency and excellent thermal radiation intensity of ultra-wideband enable it to be deeply used in energy absorption and conversion applications.

Dependency of crossover point on absorption changes in bilayer diffusion reflection measurements.

A better understanding of diffusion reflection (DR) behavior may allow it to be used for more noninvasive applications, including the development of in vivo non-damaging techniques, especially for medical topical diagnosis and treatments. For a bilayer opaque substance where the attenuation of the upper layer is larger than the attenuation of the lower layer, the DR crossover point ( ) is location where the photons coming from the bottom layer start affecting the DR. We aim to study the dependency of the on absorption changes in different layers for constant scattering and top layer thickness. Monolayer and bilayer optical tissue-like phantoms were prepared and measured using a DR system. The results were compared with Monte Carlo simulations. There is an agreement between the experiments and the simulations. correlates with the square root of the absorption coefficient ratio of the lower layer to the top layer. The experimental findings support and validate the theoretical prediction describing the dependency of the on the square root of the ratio of the layers' absorption coefficients. In addition, a secondary breaking point is suggested to be observed experimentally at the entrance to the noise area.

DFT electronic structure investigation of chromium ion-implanted cupric oxide thin films dedicated for photovoltaic absorber layers

This study explores the enhancement of cupric oxide (CuO) thin films for photovoltaic applications through chromium doping and subsequent annealing. Thin films of CuO were deposited on silicon and glass substrates using reactive magnetron sputtering. Chromium was introduced via ion implantation, and samples were annealed to restore the crystal structure. The optical and structural properties of the films were characterized using X-ray diffraction, spectrophotometry, and spectroscopic ellipsometry. Results indicated that implantation reduced the absorbance and conductivity of the films, while annealing effectively restored these properties. Sample implanted with 10 keV energy and 1 × 1014 cm−2 dose of Cr ions, after annealing had sheet resistance of 1.1 × 106 Ω/sq compared to 1.7 × 106 Ω/sq for non implanted and annealed CuO. Study of crystalline structure confirmed the importance of annealing as it reduced the stress present in the material after deposition and implantation. Density Functional Theory (DFT) calculations were performed to investigate the electronic structure and optical properties of CuO with varying levels of chromium doping. Calculations revealed an energy gap of 1.8 eV for undoped CuO, with significant changes in optical absorption for doped samples. Energy band gap determined using absorbance measurement and Tauc plot method had value of 1.10 eV for as deposited CuO. Samples after implantation and annealing had energy band gap value increased to about 1.20 eV. The study demonstrates that chromium doping and subsequent annealing can enhance the optical and electronic properties of CuO thin films, making them more efficient for photovoltaic applications.

Effect of Aggregated Lysozyme on Fluorescence Properties of Rose Bengal.

Protein aggregates cause abnormal states and trigger various diseases, including neurodegenerative disorders. This study examined whether the xanthene dye derivative Rose Bengal could track a series of conformational changes in protein aggregates. Using lysozyme as a model protein, aggregated proteins were prepared by heating under acidic conditions. The absorption spectra, steady-state fluorescence spectra, fluorescence quantum yield, fluorescence lifetime, and phosphorescence lifetime of a solution containing Rose Bengal in the presence of aggregated lysozyme were measured to identify their spectroscopic characteristics. The absorption spectrum of Rose Bengal changed significantly during the formation of agglomerates in heated lysozyme. Additionally, the fluorescence intensity decreased during the initial stages of the aggregation process with an increase in heating time, followed by an increase in intensity along with a red-shift of the peak wavelength. The decrease in quantum yield with a fixed fluorescence lifetime supported the formation of a nonfluorescent ground-state complex between Rose Bengal and the aggregated lysozyme. Based on the characteristic changes in absorption and fluorescence properties observed during the aggregation process, Rose Bengal is considered an excellent indicator for the sensitive discernment of aggregated proteins.

Analyzing parametric influences driving age-associated changes in absorption using a PBPK-GSA approach

The advanced age population may be susceptible to an increased risk of adverse effects due to increased drug exposure after oral dosing. Factors such as high-interindividual variability and lack of data has led to poor characterization of absorption's role in pharmacokinetic changes in this population. Physiologically based pharmacokinetic (PBPK) models are increasingly being used during the drug development process, as their unique qualities are advantageous in atypical scenarios such as drug-drug interactions or special populations such as older people. Along with relying on various sources of data, auxiliary tools including parameter estimation and sensitivity analysis techniques are employed to support model development and other applications. However, sensitivity analyses have mostly been limited to localized techniques in the majority of reported PBPK models using them. This is disadvantageous, since local sensitivity analyses are unsuitable for risk analysis, which require assessment of parametric interactions and proper coverage of the input space to better estimate and subsequently mitigate the effects of the phenomenon of interest. For this reason, this study seeks to integrate a global sensitivity analysis screening method with PBPK models based in PK-Sim® to characterize the consequences of potential changes in absorption that are often associated with advanced age. The Elementary Effects (Morris) method and visualization of the results are implemented in R and three model drugs representing Biopharmaceutical Classification System classes I-III that are expected to exhibit some sensitivity to three age-associated hypotheses were successfully tested.

Direct detection of the chloride release and uptake reactions of Natronomonas pharaonis halorhodopsin

Membrane transport proteins undergo multistep conformational changes to fulfill the transport of substrates across biological membranes. Substrate release and uptake are the most important events of these multistep reactions that accompany significant conformational changes. Thus, their relevant structural intermediates should be identified to better understand the molecular mechanism. However, their identifications have not been achieved for most transporters due to the difficulty of detecting the intermediates. Herein, we report the success of these identifications for a light-driven chloride transporter halorhodopsin (HR). We compared the time course of two flash-induced signals during a single transport cycle. One is a potential change of Cl--selective membrane, which enabled us to detect tiny Cl--concentration changes due to the Cl- release and the subsequent Cl--uptake reactions by HR. The other is the absorbance change of HR reflecting the sequential formations and decays of structural intermediates. Their comparison revealed not only the intermediates associated with the key reactions but also the presence of two additional Cl--binding sites on the Cl--transport pathways. The subsequent mutation studies identified one of the sites locating the protein surface on the releasing side. Thus, this determination also clarified the Cl--transport pathway from the initial binding site until the release to the medium.

A colorimetric Ag+ chemosensor based on a cyclometalated ruthenium complex with deprotonated 2-phenylbenzimidazole

A cyclometalated ruthenium complex (1) using 2-phenylbenzimidazole as a C,N-ligand was developed as a colorimetric chemosensor to detect Ag+ ions. Upon the addition of Ag+ ions, the absorption spectra of complex 1 demonstrated no change in CH3CN solution. However, an excellent solution color change from dark-green to purple and absorption spectral change with a blue-shift of 27 nm (from 612 to 585 nm) were clearly observed after Ag+ ions were added to the solution of 1 with 2-fold of fluoride (denoted as 1 + F−). When Ag+ ions were replaced by other common metal ions, the solution color changed from green to red. Therefore, the solution of 1 + F− can be used to distinguish Ag+ from the other common metal ions. The absorption intensity at 612 nm exhibited a good linear correlation for the detection of Ag+ ion from 0 to 4 µM with a detection limit of 0.34 µM. According to the absorption and 1HNMR spectral changes of complex 1, the reaction mechanism is proposed to be as a coordination between silver ion and the deprotonated nitrogen in imidazole. However, the interactions of other metal ions with 1 + F− are related to a proton transfer process.

Syntheses and Applications of Coumarin-Derived Fluorescent Probes for Real-Time Monitoring of NAD(P)H Dynamics in Living Cells across Diverse Chemical Environments.

Fluorescent probes play a crucial role in elucidating cellular processes, with NAD(P)H sensing being pivotal in understanding cellular metabolism and redox biology. Here, the development and characterization of three fluorescent probes, A, B, and C, based on the coumarin platform for monitoring of NAD(P)H levels in living cells are described. Probes A and B incorporate a coumarin-cyanine hybrid structure with vinyl and thiophene connection bridges to 3-quinolinium acceptors, respectively, while probe C introduces a dicyano moiety for replacement of the lactone carbonyl group of probe A which increases the reaction rate of the probe with NAD(P)H. Initially, all probes exhibit subdued fluorescence due to intramolecular charge transfer (ICT) quenching. However, upon hydride transfer by NAD(P)H, fluorescence activation is triggered through enhanced ICT. Theoretical calculations confirm that the electronic absorption changes upon the addition of hydride to originate from the quinoline moiety instead of the coumarin section and end up in the middle section, illustrating how the addition of hydride affects the nature of this absorption. Control and dose-response experiments provide conclusive evidence of probe C's specificity and reliability in identifying intracellular NAD(P)H levels within HeLa cells. Furthermore, colocalization studies indicate probe C's selective targeting of mitochondria. Investigation into metabolic substrates reveals the influence of glucose, maltose, pyruvate, lactate, acesulfame potassium, and aspartame on NAD(P)H levels, shedding light on cellular responses to nutrient availability and artificial sweeteners. Additionally, we explore the consequence of oxaliplatin on cellular NAD(P)H levels, revealing complex interplays between DNA damage repair, metabolic reprogramming, and enzyme activities. In vivo studies utilizing starved fruit fly larvae underscore probe C's efficacy in monitoring NAD(P)H dynamics in response to external compounds. These findings highlight probe C's utility as a versatile tool for investigating NAD(P)H signaling pathways in biomedical research contexts, offering insights into cellular metabolism, stress responses, and disease mechanisms.

The influence of COVID-19 pandemic on body mass and cardiopulmonary endurance of Chinese adolescents: a longitudinal follow-up study.

With the spread and spread of COVID-19 around the world, youth's learning, lifestyle and health have been greatly affected. Based on the current research, there is no adequate analysis of the development of young people's physique and heart and lung health during COVID-19, and there is a lack of relevant targeted research. The aim of this study was to investigate the changes of BMI and Maximum Oxygen Absorption (VO2max) in 12-14 year old teenagers before and after COVID-19. The BMI, 1,000/800 m running time and associated data related to 29,813 individuals between 2019 and 2022 were collected by cluster sampling, and the changes of BMI Z and VO2max before and after the outbreak were analyzed. Moreover, the relationship between BMI and cardiovascular endurance was analyzed by means of multi-linear stepwise regression. The covariance analysis models indicated that compared with 2019, adolescent weight, BMI, and 1,000/800 m running time showed varying degrees of growth in 2020, while lung capacity decreased. All indicators achieved rapid rebound in 2021 and 2022 (p < 0.01); the one-way analysis of variance models indicated that The BMI Z score and VO2max of adolescents showed growth and decline in 2020, respectively, and achieved rapid recovery and development in 2021 and 2022 (p < 0.01). The results of the multiple linear stepwise regression analysis indicate that, after the years of BMI Z and novel coronavirus infection were included (△R2 = 0.179), adolescents' overweight and obesity were positively correlated with the maximum oxygen uptake (B = 0.643, 95%CI = 0.634 ~ 0.652); There is a negative correlation between weight loss and maximum oxygen uptake (B = -0.510, 95%CI = -0.537~-0.484); The year of novel coronavirus infection was positively correlated with the maximum oxygen uptake of adolescents (B = 0.116, 95%CI = 0.107~0.125). This study shows that the impact of COVID-19 on BMI and heart and lung health in adolescents is significant. Young people of all ages and sexes showed similar developmental trends.

The impact of ammonium hydroxide flow rate on iron oxide nanoparticle hydrodynamic size and colloidal stability

Precise control over the synthesis of iron oxide nanoparticles is essential to achieving optimal particle characteristics such as size, hydrodynamic size, polydispersity index, and zeta potential, all of which significantly influence colloidal stability. The commonly used co-precipitation technique often leads to high polydispersity and variable particle sizes, resulting in poor colloidal stability. This study demonstrates that varying the ammonium hydroxide flow rate during co-precipitation significantly affects particle size, hydrodynamic size, aggregation, and colloidal stability. An optimal flow rate of 4.25 mmol/min produced smaller, more uniform, and colloidally stable nanoparticles. Nanoparticle tracking analysis showed that this flow rate resulted in the smallest and most consistent hydrodynamic size of 123.3 ± 0.7 nm, while both higher and lower flow rates yielded larger and more polydisperse particles, up to 155.8 ± 20 nm. Dynamic light scattering confirmed that the 4.25 mmol/min rate produced the lowest polydispersity index of 0.21 ± 0.04, indicating the highest uniformity. Additionally, UV-Vis measurements demonstrated that nanoparticles synthesized at this optimal flow rate exhibited minimal changes in absorbance over 24 h, indicating superior colloidal stability. This study highlights the importance of optimizing the flow rate during the co-precipitation synthesis of IONPs to control particle hydrodynamic size and polydispersity, which are crucial parameters for numerous biomedical, chemical, and environmental applications.

Identification of Pristine and Protein Corona Coated Micro- and Nanoplastic Particles with a Colorimetric Sensor Array.

A colorimetric sensor array has been developed to differentiate various micro- and nanoplastic particles (MNPs), both pristine and those coated with a protein corona, in buffered water. This array utilizes five distinct cross-reactive chemo-responsive dyes, which exhibit changes in visible optical absorbance upon interaction with MNPs. Although no single dye responds exclusively to either pristine or protein-corona-coated MNPs, the collective shifts in color across all dyes create a unique molecular fingerprint for each type of MNP. This method demonstrates high sensitivity, capable of detecting MNPs of various sizes (50 nm, 100 nm, and 2 μm) and differentiating them from controls at concentrations as low as 10 ng/mL using standard chemometric techniques, ensuring accurate results without error. Additionally, the method can effectively distinguish between pristine and protein-corona-coated polystyrene MNPs. This colorimetric approach offers a rapid, cost-effective, and accurate method for monitoring MNP pollution and assessing their prior interactions with biological systems.

Evaluation of Microbial Degradation of Thermoplastic and Thermosetting Polymers by Environmental Isolates

In this study, a microbial–enzymatic strategy was pursued to address the challenge of degrading thermoplastic and thermosetting polymers. Environmental microorganisms were isolated, and their enzymatic activities were assessed using colorimetric assays to evaluate their potential for producing enzymes capable of degrading these polymers. Microorganisms demonstrating higher positivity in the enzymatic assays were selected for a 30-day biodegradation experiment, in which epoxy resins, polyethylene terephthalate, or polystyrene served as the sole carbon source. The effectiveness of biodegradation was assessed through the ATR-FTIR analysis of the chemical composition and the SEM examination of surface characteristics before and after degradation. The results indicated that thermoplastic compounds were more susceptible to microbial degradation, exhibiting greater changes in absorbance. In particular, PET treated with Stenotrophomonas sp. showed the most significant efficacy, achieving a 60.18% reduction in the area under the curve with a standard error of ± 3.42 when analyzed by FTIR spectroscopy. Significant alterations in surface morphology were noticed in thermoplastic compounds. In contrast, thermosetting compounds demonstrated lower reactivity, as evidenced by the absence of band shifts in FTIR spectra and minor changes in bond absorbance and surface morphology.

Abstract We092: Naltrindole Attenuates Superoxide Release in Polymorphonuclear Leukocytes by a Novel Mechanism devoid of Delta opioid receptor antagonism Related to Reduced Intracellular Calcium Levels

Introduction: Naltrindole (NTI), known as a delta opioid receptor antagonist, inhibited phorbol 12-myristate 13-acetate (PMA) induced superoxide (SO) release in polymorphonuclear leukocytes (PMNs). PMNs do not express opioid receptors. We propose NTI reduces PMN SO by reducing intracellular calcium (Ca 2+ ). To test this hypothesis, we did experiments using KB-R7943 (KB) as a positive control, known to reduce intracellular Ca 2+ via inhibition of the reverse mode Na + /Ca 2+ exchanger. Naloxone (NX), a broad-spectrum opioid receptor antagonist, was used as a negative control. We predict that NTI will diminish PMA-induced PMN SO release similar to KB, while NX will have no effect, and that there will be no difference in cell viability compared to vehicle controls. Methods: Male Sprague Dawley (SD) rat PMNs (5x10 6 ) were incubated for 15 min at 37 o C in the presence or absence (dH 2 O vehicle control) of NTI (10 - 200 µM), KB (5-20 µM), and NX (100-200 µM). PMN SO release was measured by the change in absorbance at 550 nm over 420 sec via ferricytochrome c reduction after PMA stimulation (100 nM). The cell viability was determined microscopically by 0.2% trypan blue exclusion at the end of PMN SO release assay. Data were analyzed using ANOVA Fisher’s PLSD post-hoc test. Results: NTI significantly decreased PMN SO release at 200 μM (n=10, 0.196±0.06, p&lt;0.05) compared to vehicle control (n=22, 0.731±0.07) or NX 100/200 μM (n=3, 0.593±0.06), and NTI at 100 μM (n=7, 0.461±0.08, p&lt;0.05) versus vehicle control. Likewise, KB significantly decreased PMN SO release at 20 μM (n=7, 0.507±0.07), 10 μM (n=7, 0.552±0.07), and 5 μM (n=5, 0.615±0.11) compared to vehicle control (n=10, 0.908±0.07). Cell viability was statistically similar (80-90±5%) among all study groups. Conclusion: NTI (10-200 μM) and KB (5-20 µM) exhibited concentration-dependent effects in reducing PMN SO release without compromising cell viability. The results suggest that the novel effect of NTI maybe mediated through a reduction in intracellular Ca 2+ and independent of delta opioid receptor antagonism. These results are consistent with the effects of NTI, KB and NX in myocardial ischemia/reperfusion injuries. Future studies will assess the effects of NTI on ROS attenuation in human umbilical vein endothelial cells.