Search Results (16,777)

The biological compatibility of endodontic sealers is a key determinant of periapical tissue healing. This in vitro study investigated the cytotoxic, pro-inflammatory, and redox-related effects of eight endodontic sealers on human periodontal ligament fibroblasts (HPdLFs): Biopulp (Chema-Elektromet), AH Plus (Dentsply Sirona), MTA Fillapex (Angelus), EndoSeal MTA (Maruchi), GuttaFlow (Coltène), AH Plus Bioceramic (Dentsply Sirona), TotalFill BC (FKG Dentaire SA), and BioRoot TM (Septodont). Cells were exposed for 24 h to 10-fold-diluted sealer extracts prepared in accordance with the manufacturers’ instructions, while control samples underwent identical procedures without sealer contact. Oxidative stress biomarkers, antioxidant defense parameters, protein oxidation indices, apoptotic activity (caspase-3), pro-inflammatory cytokines (IL-1, IL-6), and cell viability (MTT assay) were assessed. Under the applied conditions, all materials induced only limited global oxidative stress, with most alterations reflecting selective protein and glycoxidative modifications. Nevertheless, AH Plus, MTA Fillapex, and the calcium hydroxide-based Biopulp exhibited a less favorable redox profile and greater protein oxidation compared with calcium silicate-based sealers. AH Plus and EndoSeal MTA were associated with increased IL-6 release, whereas EndoSeal MTA moderately elevated IL-1 levels. BioRoot TM demonstrated the lowest cytokine expression, and TotalFill BC preserved high cell viability. Caspase-3 activity remained comparable across all experimental groups, indicating minimal induction of apoptosis. Full article

The aim of this study was to investigate the changes in selected physical properties of freeze-dried vegetable snacks packed in edible films based on pork gelatin of different concentrations (8 and 12%), during storage at temperatures of 4 °C and 20 °C for periods of 3 and 6 months. The scope of this work includes the preparation of freeze-dried carrot snacks, obtaining edible films, packaging the snacks, and testing selected physical properties. The results show that storage time and temperature significantly affected the quality of the freeze-dried snacks. Water activity increased from an initial value of approximately 0.12 in the control samples to values ranging between 0.27 and 0.60 after storage, depending on gelatin concentration, temperature, and storage duration. The lowest water activity values (≈0.27–0.28) were observed for samples stored at 20 °C for 3 months, regardless of gelatin concentration, whereas storage for 6 months resulted in water activity values close to 0.5–0.6. Dry matter content decreased from about 97% in the control samples to values ranging from approximately 73.6% to 87.0% for samples coated with 8% gelatin and from 78.5% to 86.7% for samples coated with 12% gelatin, with greater reductions observed at longer storage times and lower storage temperature. Mechanical analysis indicated a strengthening of product structure after 3 months of storage, followed by a marked reduction in compression force—almost tenfold—after 6 months, indicating structural weakening. Color saturation (C) increased after 3 months of storage (values around 40–42), but significantly decreased after 6 months, reaching values as low as approximately 13–24, particularly at 20 °C. Porosity remained high throughout storage, generally in the range of 94–95%, although microscopic analysis revealed progressive pore collapse after 6 months of storage. Overall, a storage temperature of 20 °C and a storage time of 3 months were identified as the most favorable conditions for freeze-dried carrot snacks packed in edible films with both 8% and 12% gelatin, ensuring lower water activity, higher dry matter content, and better structural stability. Full article

The study aimed to assess the influence of two packaging methods (under vacuum, VP vs. air, AP) on the quality of fish balls from carp (Cyprinus carpio) stored at +4 °C up to 14 days after preparation. The air-packed and vacuum-packed fish balls were analyzed for physicochemical parameters, microbiological status, and sensory characteristics. The packaging method and storage time interaction significantly (p < 0.05) affected the acid value (AV) and peroxide value (PV), as well as the thiobarbituric acid reactive substance index (TBARS), with lower values of these parameters observed in vacuum-packed samples at 7 d (AV, PV, TBARS), 9 d (TBARS), 12 d (PV) and 14 d (TBARS) of storage. Moreover, vacuum packaging helped maintain a beneficial oil absorption and pH, and partially slowed down the occurrence of undesirable changes in color, i.e., the decrease in redness of semi-raw fish balls or increase in yellowness of deep-fried products. Based on the overall quality values, the air-packed fish balls were sensory acceptable for up to 9 days, while the vacuum-packed fish balls were acceptable up to 12 d. The bacterial counts (total viable counts—TVC, psychrotrophic bacterial counts—PBC, total staphylococcal counts—TSC, sulfite-producing bacteria counts—SPBC, and lactic acid bacteria counts—LABC) increased during storage. Although the rate and pattern of growth varied depending on the packaging, fish balls maintained the recommended microbiological quality throughout the entire storage period. The VP method inhibited the growth of TVC, PBC, TSC, and SPBC relative to the AP method, while the VP method showed a higher increase in LABC. The results indicated that vacuum packaging appears to be an effective approach to prolong the shelf life of fish balls made from carp. Additionally, developing this convenient food product could be a valuable strategy to enhance consumer acceptance and promote the use of widely farmed carp species. Full article

Cement is one of the primary construction materials in ground improvement applications that employ the binder stabilization method. Due to the high carbon dioxide emissions in its production, evaluating environmentally friendly alternative binder materials is a popular research topic. Industrial by-products such as fly ash (FA) and ground granulated blast-furnace slag (GGBS) are alternatives to traditional cement, especially in deep soil mixing (DSM) applications, and can enhance sustainability in construction projects. Since these materials are not active when used alone, alkali activation is proposed to modify them as binding agents in ground improvement projects. This study presents the outcomes of a primary laboratory test phase for on-site applications. FA and GGBS precursors supplied by local plants, mixed with soil and activator solutions in applicable ratios, and samples were prepared for laboratory tests. Unconfined compression tests were applied with strain measurements after several curing durations, between 1 and 54 weeks. Average compression strength and modulus of elasticity values were recorded at approximately 12.3 MPa and 11.7 GPa, respectively, in samples with an average dosage. An empirical correlation between the strength and stiffness modulus was found. Strength and stiffness values were comparable to traditional materials, indicating the potential of these industrial by-products when activated under alkali conditions. The carbon footprints of cement and alkali-activated by-products were compared based on calculated CO₂-eq emissions. Full article

Currently, only a limited number of Mark–Houwink–Sakurada (MHS) equations are available for chitin, and their applicability is constrained by the narrow range of suitable solvent systems. The Mark–Houwink–Sakurada (MHS) equation is a widely used and practical approach for estimating polymer molecular weight from intrinsic viscosity measurements, particularly when chromatographic techniques are not readily accessible. This study aimed to establish new MHS equations for chitin to facilitate reliable molecular weight determination across different solvents and temperatures. Chitin samples with varying molecular weights were prepared via H₂O₂ degradation, and their weight-average molecular weights (Mw) were determined by high-performance size-exclusion chromatography (HPSEC). Intrinsic viscosity ([η]) was measured using a capillary viscometer at 25 and 30 °C in three solvent systems: 5% LiCl/N,N-dimethylacetamide (LiCl/DMAc), 8% NaOH/4% urea, and 10% NaOH/0.3% tannic acid (w/w). Double-logarithmic plots of Mw versus [η] were constructed to derive the corresponding MHS equations. At identical molecular weights and temperatures, intrinsic viscosity followed the order: LiCl/DMAc > NaOH/urea > NaOH/tannic acid. Increasing temperature led to higher intrinsic viscosity and conformation parameter (a) values. Chitin dissolved in LiCl/DMAc and NaOH/urea exhibited rod-like conformations, with a values ranging from 0.79 to 0.97, whereas chitin in NaOH/tannic acid displayed random coil behavior (a = 0.56–0.69). These established MHS equations expand the solvent applicability for chitin molecular weight determination and provide insights into its solution conformation under different chemical environments. Full article

Trace amounts of CO in H₂-rich gas can poison Pt electrodes in proton-exchange-membrane fuel cells, necessitating selective CO removal. Preferential oxidation of CO (PROX) offers an efficient route to oxidize CO while preserving H₂. Although noble-metal-based catalysts are widely used, their high cost has driven interest in non-precious alternatives. Co₃O₄–CeO₂ catalysts have emerged as particularly promising due to their high activity and stability. Two series of Co–Ce/SiO₂ catalysts were prepared via impregnation: in the first, Ce was introduced and calcined prior to Co deposition; in the second, Co and Ce nitrates were co-deposited from a mixed aqueous solution. The latter method enhances the interaction between Co₃O₄ and CeO₂, increasing the availability of surface oxygen species. Stability tests on the most active sample demonstrated remarkable durability, maintaining near-complete CO conversion over 100 h on dry stream. Full article

In-tube solid-phase microextraction (IT-SPME) is an advanced microextraction technique in which a sample solution flows through a capillary containing an internal stationary phase, enabling efficient extraction and preconcentration of target analytes. The online coupling to liquid chromatography is a key advantage of this technique, enabling full automation and high analytical throughput, both of which are significant for food analysis. Recent advances have focused on developing novel sorbent materials that respond to external stimuli (e.g., magnetic, electrical, or thermal) and on integrating them into emerging chromatographic platforms. Moreover, key operational parameters, including sample volume, pH, phase thickness, and the capillary’s dimensions (length and inner diameter), must be optimized to achieve enhanced selectivity, speed, and sensitivity. Despite this, the literature still lacks updated reviews of SPME concepts and their innovations for versatile applications in food matrices. Hence, this review outlines the fundamental principles of IT-SPME while highlighting key parameters that affect analytical performance. Finally, we provide a literature review of SPME applications in food analysis over the past 6 years, while exploring current trends and future directions for SPME development and enhanced applications in food science. Full article

Background/Objectives: Adeno-associated viruses (AAVs) are widely used gene therapy vectors; yet their physicochemical stability and chromatographic behavior are highly sensitive to the solution conditions they are in. Effective separation of full (F), empty (E), and partially filled (P) capsids—most commonly achieved by anion exchange (AEX) chromatography—is essential for standard analytical characterization, process development, and product safety. However, conventional AEX methods rely on low-conductivity alkaline mobile phases with low salt, which promote capsid binding and therefore higher resolution, at the expense of structural stability. Conversely, formulations such as near-neutral buffers might preserve capsid integrity but often impair AEX retention and separation resolution. Methods: Here, we extend a mechanistic investigation using AAV8 capsids as a model system, focusing on detailed capsid interactions with strong AEX, and present novel AAV8 separation strategies on a weak AEX stationary phase. Results: By systematically varying buffer pH and ionic strength, we identify operational regimes that balance capsid stability with chromatographic separation efficiency. In parallel, we introduce an integrated two-dimensional (2D) in-line buffer exchange configuration that decouples AEX performance from sample formulation, enabling robust separation of stability-optimized, high-salt matrices without off-line desalting. Conclusions: By elucidating the roles of capsid charge modulation, ligand physicochemical properties, and local microenvironmental buffering, this study establishes practical design principles for stability-preserving chromatography. It lays a foundation for more reliable analytical and future preparative AAV workflows. Full article

Microfluidics-based preparation methods for cell-laden hydrogel microspheres are well-suited for large-scale comparative analysis of single or few cells. However, in existing studies, the preparation of cell-laden hydrogel microspheres and the cell culture process are typically separated, requiring the fabricated microspheres to be eluted and transferred from the preparation device to cell culture dishes or plates for cultivation. This transfer process can easily compromise sterility, while conventional cell culture methods consume more reagents and cause microsphere stacking, hindering single-cell observation and analysis. To address these issues, this paper presents an integrated microfluidic chip that sequentially enables droplet generation with cell encapsulation, gel droplet solidification, hydrogel microsphere trapping, and microsphere-based cell culture and analysis, facilitating the cultivation and observation of single or small numbers of cells. Integrating cell-laden microsphere preparation and 3D cell culture within a sealed chip structure reduces contamination risks associated with cell transfer, enables automation of multiple cell analysis workflows, and minimizes reagent and sample consumption. Using polydimethylsiloxane (PDMS) with good gas permeability and processability as the chip material, biocompatible fluorinated oil was selected as the oil phase for microsphere preparation. A mild sodium alginate-calcium ion gelation system was employed, where calcium ions were released under acidic conditions after droplet generation to trigger solidification, yielding uniform hydrogel microspheres. Under optimized conditions, the single-cell encapsulation efficiency for test samples of human myeloid leukemia cells (K562) was 33.8% ± 1.8%, with a size uniformity coefficient of variation (CV) reaching 3.85%. Cells encapsulated within hydrogel microspheres were cultured in 286 on-chip independent cell culture chambers, achieving >95% viability after 24 h. Full article

A sequenced ultrasonic atomization coupled with a pyrolysis process is developed to synthesize a series of cross-scale (Co/Cu)-NC catalysts. The catalysts demonstrate high metal utilization efficiency with a metal loading of 22.45 ± 0.07 wt%. Electrochemical evaluations for the oxygen reduction reaction (ORR) suggest that the best (Co/Cu)-NC catalysts are prepared with a Co/Cu ratio of 1/1 and a calcination temperature of 800 °C, which achieve a half-wave potential of 0.87 V and an electrochemical impedance spectroscopy semicircle radius as low as 30 ohms. Linear sweep voltammetry measurements indicate that (Co/Cu)-NC catalysts exhibit the highest current density. Under a potential of −0.73 V versus the reversible hydrogen electrode, (Co/Cu)-NC catalysts demonstrate long-term stability with the CO Faradaic efficiency of about 70% for catalyzing carbon dioxide reduction reaction (CO₂RR). Overall, the above metrics identify CoCu-800 as the optimal bifunctional catalyst among the tested samples for ORR and CO₂RR under the investigated conditions. Full article

Past studies have reported that carbon dioxide emissions during combustion vary depending on the tree species used as fuel. It has also been reported that the moisture content of wood affects combustion efficiency. From this perspective, identifying the tree species and moisture content is crucial for utilizing waste wood as a resource. Therefore, this study verified the effectiveness of non-destructive diagnosis using terahertz waves. Samples with adjusted moisture content were prepared for eight types of wood. Each wood sample was irradiated with multiple broadband terahertz electromagnetic waves, and their transmission characteristics were compared. Experimental results revealed a strong negative correlation (Pearson Correlation coefficient: −0.98~−0.71 square meter/gram) between the sample’s specific gravity and transmittance when irradiated with 65 GHz and 90 GHz sub-terahertz waves. This trend was particularly pronounced during 90 GHz sub-terahertz irradiation. Furthermore, it was found that the trend in transmittance variation differed depending on the wood’s moisture content. These results indicate that terahertz waves are effective as a wood identification method capable of distinguishing between coniferous and broadleaf trees. Furthermore, they are considered effective for predicting wood moisture content. This research is expected to contribute to promoting wood recycling and the sustainable use of wood resources. Full article

This study introduces an electrochemical sensing platform based on bimetallic CoAg/rGO and CuAg/rGO nanocomposites for the detection of 1,3-dinitrobenzene (DNB), a highly toxic nitroaromatic compound commonly encountered in industrial effluents and contaminated water systems. The prepared nanocomposites were characterized using SEM, TEM, AFM, XPS, and electrochemical techniques, providing detailed insight into their structural, morphological, and surface properties relevant to electrochemical sensing. The electrochemical behavior of DNB was investigated in phosphate buffer solutions using cyclic voltammetry under optimized experimental conditions. Both CoAg/rGO and CuAg/rGO electrodes exhibited pronounced electrocatalytic activity towards the reduction in DNB, characterized by well-defined reduction peaks. The developed sensors exhibited good analytical performance, with limits of detection of 2.21 µM and 2.47 µM for the CuAg/rGO and CoAg/rGO electrodes, respectively, both showing linear responses in the concentration range of 5–50 µM. Moreover, a clear response to DNB was obtained in the presence of phenols as interferents as well as in spiked real water samples. The integration of characterization results with electrochemical measurements and validation in real water samples supports process-oriented research in environmental monitoring and electrochemical process control. These results confirm that bimetallic rGO-based nanocomposites represent efficient and cost-effective electrode materials for the electrochemical detection of 1,3-dinitrobenzene. Full article

Background/Objectives: Rapid diagnostic tests (RDTs) for human immunodeficiency virus (HIV) are widely used, but most kits lack standardized internal quality control (IQC) materials. In this study, we aimed to develop and evaluate a plasma-based IQC compatible with five HIV RDT brands and with proven long-term stability. Methods: Control samples at three reactivity levels were tested with five HIV RDT kits in lyophilized and liquid forms. Lyophilized samples were produced with and without trehalose, whereas liquid samples were prepared with and without StabilZyme™ SELECT Stabilizer (Stabilizer). Accelerated stability testing was performed at 37 °C and 45 °C for 28 days, and the most stable formulation was selected for long-term storage at 4 ± 2 °C and 25 ± 5 °C. Stability was assessed based on test-line visibility and signal intensity. Signal-intensity trends were analyzed using simple linear regression with a t-test on the slope; samples were considered stable when no significant trend was detected (p > 0.05). Results: Reactivity measured using the Elecsys HIV combi PT assay yielded cutoff index (COI) values of 772.65 (1:8) for the strong-positive control and 269.95 (1:25) for the weak-positive control. Trehalose-containing lyophilized samples maintained reactivity under accelerated testing at 37 and 45 °C and for 6 months at 4 ± 2 °C and 25 ± 5 °C, with no significant change in signal intensity (p > 0.05). Conclusions: The plasma-based IQC materials were compatible with all five HIV RDTs, and trehalose-stabilized lyophilized plasma showed high stability, supporting transport and storage without strict cold-chain requirements. Full article

The growing need for a cleaner, sustainable environment has increased interest in reusing waste materials that cause pollution. In this research, the mechanical (dry density, compressive, and tensile strength) and also durability properties (sorptivity, rate of water absorption, chloride ion resistance, and resistance to freeze–thaw) of concrete were studied by partially substituting cement with brick powder (BP) and sand with quarry dust (QD). The proportions of brick powder replacement with cement were in the range of 5%, 10%, 15%, and 20% by weight. Likewise, QD was used in the range of 15%, 30%, 45%, and 60% by weight of natural sand. Both materials were used separately as well as simultaneously in concrete. Concrete mixtures were prepared, tested after curing, and then compared with conventional concrete. The water–cement (w/c) ratio was kept constant at 0.55 for all the mixes. According to experimental results, the concrete made with brick powder and quarry dust resulted in improved dry density. After curing for 28 and 56 days, the compressive and splitting tensile strengths increased by substituting cement with brick powder up to 15%. Brick powder showed a higher strength activity index than required according to the standard. Also, compressive and splitting tensile strengths significantly increased by replacing natural sand with quarry dust up to 60% at all curing ages. Combined mixes with partial replacements of cement and sand with brick powder and quarry dust, respectively, also showed improvements in the compressive and splitting tensile strength at all ages. Sorptivity and rate of water absorption decreased with the addition of BP and QD. Moreover, brick powder and quarry dust mixes showed higher resistance to chloride ion penetrability and higher resistance to freeze–thaw as the replacement level increased. Microstructural analysis of hard concrete samples also confirmed the enhanced mechanical strength and durability due to brick powder and quarry dust. Full article

Black pepper is the most widely used spice crop globally and has significant economic value, making it a target for economically motivated adulteration. A wide range of organic and inorganic bulking materials has been used as adulterants in black pepper. Development of rapid non-targeted screening methods for use at different stages of the black pepper supply chain is extremely important for the identification and prevention of evolving fraudulent practices. This study has assessed the potential of benchtop Fourier Transform infrared with attenuated total reflectance (FTIR-ATR), benchtop Fourier Transform near-infrared (FT-NIR), and two handheld NIR spectrometers, coupled with chemometrics, for the discrimination of black pepper (Piper nigrum), pepper from other species and genera (non-Piper nigrum) and a broad range (n = 27) of endogenous and exogenous adulterants. Spiked samples were prepared to imitate pepper adulteration with seven different adulterants at five levels of adulteration (5%, 25%, 50%, 75%, 95% w/w). Orthogonal partial least squares discriminant analysis (OPLS-DA) achieved 100% total prediction accuracy for both FTIR-ATR and FT-NIR in differentiating authentic Piper nigrum and adulterant samples. The handheld microNIR 1700ES resulted in a 91.30% correct classification rate, while the SCiO model achieved 86.96% prediction accuracy. Detection of black pepper adulteration with multiple adulterants was performed using data-driven soft independent modelling of class analogy (DD-SIMCA). The highest performance of the DD-SIMCA model was achieved by FTIR-ATR (100% sensitivity and 100% specificity) followed by FT-NIR (98% sensitivity and 99% specificity). The handheld microNIR 1700ES resulted in 95% sensitivity and 90% specificity. This study demonstrated that FTIR-ATR and FT-NIR, coupled with DD-SIMCA, can effectively detect black pepper adulteration with multiple endogenous and exogenous adulterants. The handheld NIR (microNIR1700ES) clearly demonstrated the potential for rapid and effective verification of Piper nigrum authenticity outside the laboratory. Full article