Search Results (112)

Skin repair is essential in the treatment of burns and wounds. After an injury, the concept of tissue engineering emerges to restore skin function and facilitate wound healing. This field often involves the use of biodegradable and biocompatible materials as a primary scaffold for tissue regeneration. In this study, a PHB/Collagen wound dressing mat loaded with the antimicrobial peptide LL37 was developed via electrospinning. The polymer solutions were prepared by dissolving polyhydroxybutyrate (PHB) biopolymer extracted from Cereibacter sphaeroides, commercial PHB, and marine collagen in hexafluoroisopropanol (HFIP). The resulting nanofibers were characterized using Field-Emission Scanning Electron Microscopy (FE-SEM), Thermogravimetric Analysis (TGA), X-Ray Diffractometry (XRD), and an Optical Tensiometer. Antibacterial activity assessments were conducted against Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922). Degradability studies were carried out in DMEM medium, cytotoxicity tests were performed on the L929 fibroblast cell line, and the wound healing effect was investigated on the HS2 keratinocyte cell line. To evaluate the properties of the designed material under in vitro conditions, the morphology of cells on the nanofiber was examined using an inverted light microscope. The findings demonstrated that the nanofibers were biocompatible in vitro and exhibited no toxic effects. And, compared to the control groups, the 5.56 nmol LL37-loaded PHB/Collagen nanofibers significantly enhanced wound closure by 15–30% and effectively reduced the viability of S. aureus and E. coli by 20–25% and approximately 80–85%, respectively. These results highlight the therapeutic potential of LL37-loaded PHB/Collagen nanofibers for use in wound healing applications. Full article

The estimation of soil hydraulic properties—such as water retention and hydraulic conductivity—is essential for irrigation management and agro-hydrological modeling. This study presents the development and application of SOILHP, a low-cost, IoT-integrated device designed to monitor laboratory evaporation experiments for the estimation of soil hydraulic properties using inverse modeling tools. SOILHP incorporates mini-tensiometers, a precision balance, microcontrollers, and cloud-based data logging via Google Sheets. SOILHP enables the remote, real-time acquisition of soil pressure head and mass variation data without the need for commercial dataloggers. Evaporation experiments were conducted using undisturbed soil samples, and inverse modeling with Hydrus-1D was used to estimate van Genuchten–Mualem parameters. The optimized parameters showed low standard errors and narrow 95% confidence intervals, demonstrating the robustness of the inverse solution, confirming the device’s sensors accuracy. Forward simulations of internal drainage were performed to estimate the field capacity under different drainage flux criteria. The field capacity results aligned with values reported in the literature for tropical soils. Overall, SOILHP proved to be a reliable and economically accessible alternative for monitoring evaporation experiments aimed at fitting parameters of analytical functions that describe water retention and hydraulic conductivity properties within the soil pressure head range relevant to agriculture. Full article

Water-use efficiency (WUE) plays a crucial role in sustainable crop production, particularly in water-limited environments where maximizing natural resource use is essential. This study evaluated the physiological and agronomic performance of two Piper nigrum cultivars, Clonada and Uthirankotta, grown under different soil water potential conditions. The trial was conducted in a 1930 m² field using a randomized block design and drip irrigation system, calibrated to 3.55 L h⁻¹ with a uniformity of 97%. Soil water availability was managed based on daily tensiometer readings at 20 and 30 cm depths, triggering irrigation at defined tensions (10–55 kPa). Clonada exhibited higher net CO₂ assimilation rates (A) and stomatal conductance (g_s), but these responses did not lead to higher yields. In contrast, Uthirankotta consistently maintained superior water-use efficiency and yield across all soil moisture conditions by favoring water conservation and targeted biomass allocation over maximized gas exchange. Both cultivars performed optimally at a soil water potential range of 25–35 kPa, with declines in yield and gas exchange parameters at higher tensions (45–55 kPa). Under such conditions, Uthirankotta was 51.3% more water-use efficient and 40.8% more productive than Clonada. Based on this, a Principal Component Analysis (PCA) further demonstrated distinct physiological profiles, underscoring trade-offs between yield and water-use strategies. These results highlight the significance of cultivar selection for optimizing WUE and provide valuable insights into irrigation management and breeding programs aimed at boosting black pepper performance under water-limited conditions. Full article

The paper shows the effect of using a lubricant in the form of an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF₆), on the tribological properties of a hydrogenated diamond-like coating (DLC) doped with tungsten a-C:H:W. The coatings were deposited on 100Cr6 steel by plasma-enhanced chemical vapor deposition PECVD. Tribological tests were carried out on a TRB³ tribometer in a rotary motion in a ball–disc combination. 100Cr6 steel balls were used as a counter-sample. Friction and wear tests were carried out for discs made of 100Cr6 steel and 100Cr6 steel discs with a DLC coating. They were performed under friction conditions with and without lubrication under 10 N and 15 N loads. The ionic liquid BMIM-PF₆ was used as a lubricant. Coating thickness was observed on a scanning microscope, and the linear analysis of chemical composition on the cross-section was analyzed using the EDS analyzer. The confocal microscope with an interferometric mode was used for analysis of the geometric structure of the surface before and after the tribological tests. The contact angle of the samples for distilled water, diiodomethane and ionic liquid was tested on an optical tensiometer. The test results showed good cooperation of the DLC coating with the lubricant. It lowered the coefficient of friction in comparison to steel about 20%. This indicates the synergistic nature of the interaction: DLC coating–BMIM-PF₆ lubricant–100Cr6 steel. Full article

Biosurfactants are becoming increasingly popular, but industrial production of biosurfactants is difficult, partly due to high production costs resulting from the need to use expensive substrates. One economically feasible candidate is vegetable oils, which can be directly metabolized without pretreatment. The aim of this work is therefore to investigate the possibility of using vegetable oils for lipopeptide production by Serratia marcescens G8-1. The genetic background of this strain for the production of lipopeptides was investigated using a genomic approach. The biosurfactants were analysed by Ultra-Performance Liquid Chromatography coupled with Electrospray Ionisation Mass Spectrometry. The ability to reduce surface tension was investigated using a tensiometer. The results showed that the best effect in reducing surface tension was achieved by adding waste rapeseed oil. Sunflower and linseed oil also showed good results. Significantly poorer results were obtained when fresh rapeseed oil, sesame oil and pumpkin seed oil were used. The putative gene cluster for cyclic lipopeptides NRPS was identified in the genome of S. marcescens G8-1. The results obtained confirmed that serrawettin W1 is the major biosurfactant produced by S. marcescens G8-1. Of particular interest, the results showed the presence of vinylamycin when rapeseed oil was used. Full article

Alkyl sulfobetaine shows a strong advantage in the compounding of surfactants due to the defects in the size matching of hydrophilic and hydrophobic groups. The interfacial tensions (IFTs) of alkyl sulfobetaine (ASB) and xylene-substituted alkyl sulfobetaine (XSB) with oil-soluble (Span80) and water-soluble (Tween80) nonionic surfactants on a series of n-alkanes were studied using a spinning drop tensiometer to investigate the mechanism of IFT between nonionic and betaine surfactants. The two betaine surfactants’ IFTs are considerably impacted differently by Span80 and Tween80. The results demonstrate that Span80, through mixed adsorption with ASB and XSB, can create a relatively compacted interfacial film at the n-alkanes–water interface. The equilibrium IFT can be reduced to ultra-low values of 5.7 × 10⁻³ mN/m at ideal concentrations by tuning the fit between the size of the nonionic surfactant and the size of the oil-side vacancies of the betaine surfactant. Nevertheless, Tween80 has minimal effect on the IFT of betaine surfactants, and the betaine surfactant has no vacancies on the aqueous side. The present study provides significant research implications for screening betaine surfactants and their potential application in enhanced oil recovery (EOR) processes. Full article

Objectives: To examine the effects of surface treatments on the color stability, surface roughness, surface gloss, and wettability of monolithic polychromatic material jetting (MJT) 3D-printed denture material. Material and Methods: Twenty-one color variants of the same denture material (TrueDent; Stratasys, Eden, MN, USA) underwent two surface treatments (polishing only or polishing and glazing), creating 42 study groups with a total of 420 samples (n = 10 per group). The samples were manufactured using a PolyJet 3D printer (J5 DentaJet; Stratasys, Eden, MN, USA), a type of MJT 3D printer. Color measurements were taken with a digital spectrophotometer before and after the surface treatments, and quantitative color differences (ΔE₀₀ and ΔC*) were calculated using the CIE2000 system. Comparisons of ΔE₀₀ were made against the 50%:50% acceptability threshold (AT) of 1.8 and the 50%:50% perceptibility threshold (PT) of 0.8 for tooth shade, as well as the 50%:50% PT of 1.72 and the 50%:50% AT of 4.08 for gingival (pink) shade. After surface treatment, the gloss was measured using a glossmeter, surface roughness was measured with optical profilometry, and wettability was measured by contact angle measurements using an optical tensiometer. The significance of surface treatment on color changes for each color variant was evaluated using one-sided, one-sample t-tests against the AT and PT. The effects of surface treatment on surface gloss, surface roughness, contact angle, and ΔC* were analyzed using t-tests for each color variant. Pairwise comparisons between groups were made using Fisher’s Protected Least Significant Differences (α = 0.05). Results: In most cases, glazing caused the color change (ΔE₀₀) to exceed the AT and PT, with a few exceptions. Most materials exhibited a more vibrant (more saturated) appearance and statistically higher chroma, with glazed surface treatments compared to polished ones, though there were some exceptions. For all materials, the glazed samples had significantly higher gloss units than the polished ones (p < 0.0001). Additionally, all materials showed significantly higher surface roughness in glazed samples compared to polished ones (p < 0.0001 for most). The polished samples had significantly higher contact angles (p < 0.0001 for most). Conclusions: Surface treatments significantly influenced the color, surface gloss, surface roughness, and wettability of MJT 3D-printed denture materials. Glazing led to increased chroma and gloss and produced more hydrophilic surfaces, although it also increased surface roughness. These results highlight the importance of surface treatment selection in optimizing the clinical performance of MJT-fabricated dentures. Full article

This study examines a triaxial testing system for unsaturated subgrade fillers, utilizing a high-suction tensiometer and photogrammetry to more accurately simulate and analyze their mechanical behavior. Digital image correlation (DIC) technology is combined with non-contact photogrammetry, employing a multi-ray tracing method to reconstruct the 3D model of the sample and monitor its volume changes. Real-time matric suction is measured using a high-suction tensiometer, avoiding traditional suction control methods and enabling a more accurate reproduction of deformation and suction changes in unsaturated soil samples under natural conditions. This study further analyzes key parameters, such as specific volume change, suction change, and shear failure state, under varying moisture content and stress conditions, with parameter calibration for mechanical behavior performed using the BBM model. This system significantly reduces traditional experimental time, offering a new tool for studying the mechanical behavior of unsaturated subgrade fillers, with substantial theoretical value and practical application potential. Full article

The accurate measurement of soil suction is essential for understanding the behavior of unsaturated soils, particularly in soil–vegetation–atmosphere (SVA) interactions, where both energy and hydraulic gradients due to climatic action exhibit their maximum intensity. This study assesses the performance of the TEROS 21 probe, a capacitance-based water potential sensor, for measuring soil matric suction and temperature in clayey soils of the South Apennines, Italy. Laboratory tests were conducted on soil samples with varying moisture contents, and the results were compared with those obtained using the traditional filter paper (FP) method and high-capacity tensiometers (HCTs). The TEROS 21 (METER Group, Inc., Pullman, WA, USA) sensor demonstrated a reliable performance, especially at suction levels between 300 and 2000 kPa, though there was some dependency on the initial sensor conditions (wet or dry). The temperature data obtained from the TEROS 21 were verified by using a thermocouple, showing the high consistency of the readings. This study showed that the filter paper and sensor measurements aligned at a water content lower than 30% but diverged at higher levels due to method-specific accuracy limitations. The consistent sensor results confirmed the measurement’s reliability. The air-entry value (AEV) of the soil water retention data was identified at around 800 kPa, which is consistent with previous findings. Full article

Critical micelle concentration (CMC) is the main physico-chemical parameter to be determined for surfactants due to its impact on surface activity and self-assembled aggregation. The aim of the present study is to determine CMC at 40 °C of gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum by using different analytical techniques, particularly mid-infrared (MIR) spectroscopy as a rapid technique. The CMC values obtained for each hydrocolloid were relatively identical regardless of the applied technique: rheometer, conductimetry and automatic drop tensiometer (tracker). Indeed, CMC values of 55.16 g/L, 14 g/L, 6.04 g/L, 7 g/L and 3.48 g/L were obtained, respectively, for gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum by using the surface tension method (tracker). Similar results were obtained for MIR spectroscopy since CMC values of 70 g/L, 15 g/L, 7 g/L, 5 g/L and 6 g/L were observed, respectively, for gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum. The results presented here clearly demonstrate that it is possible to use MIR spectroscopy as a rapid analytical technique for the CMC determination of the investigated hydrocolloids. Full article

Frequent agricultural irrigation events continuously raise the groundwater table on loess platforms, triggering numerous loess landslides and significantly contributing to soil erosion in the Chinese Loess Plateau. The movement of irrigation water within the surficial loess layer is crucial for comprehending the mechanisms of moisture penetration into thick layers. To investigate the infiltration and evaporation processes of irrigation water, a large undisturbed soil column with a 60 cm inner diameter and 100 cm height was extracted from the surficial loess layer. An irrigation simulation event was executed on the undisturbed soil column and the ponding infiltration and subsequent evaporation processes were systematically monitored. A ruler placed above the soil column recorded the ponding height during irrigation. Moisture probes and tensiometers were installed at five depths to monitor the temporal variations in volumetric water content (VWC) and matric suction. Additionally, an evaporation gauge and an automatic weighing balance measured the potential and actual evaporation. The results revealed that the initially high infiltration rate rapidly decreased to a stable value slightly below the saturated hydraulic conductivity (K_s). A fitted Mezencev model successfully replicated the ponding infiltration process with a high correlation coefficient of 0.995. The monitored VWC of the surficial 15 cm-thick loess approached a saturated state upon the advancing of the wetting front, while the matric suction sharply decreased from an initial high value of 65 kPa to nearly 0 kPa. The monitored evaporation process of the soil column was divided into an initial constant rate stage and a subsequent decreasing rate stage. During the constant rate stage, the actual evaporation closely matched or slightly exceeded the potential evaporation rate. In the decreasing rate stage, the actual evaporation rate fell below the potential evaporation rate. The critical VWC ranged from 26% to 28%, with the corresponding matric suction recovering to approximately 25 kPa as the evaporation process transitioned between stages. The complete evaporation process was effectively modeled using a fitted Rose model with a high correlation coefficient (R² = 0.971). These findings provide valuable insights into predicting water infiltration and evaporation capacities in loess layers, thereby enhancing the understanding of water movement within thick loess deposits and the processes driving soil erosion. Full article

In the context of water restriction, the adoption of innovative technology and water saving strategies is crucial to sustainable agriculture production. Thus, we sought to emphasize the contribution of precision irrigation based on Internet of Things (IoT) technology and smart sensors for optimizing irrigation water use. The effects of different drip irrigation regimes on total dry matter (TDM), grain yield (GY) and water use efficiency (WUE) of winter wheat grown on clay-loam soil under semi-arid conditions of Tunisia have been assessed for three consecutive growing seasons. The trial included fully irrigated (FI) treatment (100% of crop evapotranspiration (ETc)), two deficit irrigation treatments (DI1, DI2 corresponding to 75 and 60% of ETc, respectively) and rainfed treatment DI3, replicated three each. The results showed that TDM and GY increase with increasing irrigation amount. At harvest, the highest TDM and GY values were recorded under FI and DI1. Reducing irrigation amount by 40% (DI2) resulted in a significant grain yield reduction, quantified as 52.7, 45.7, 30.4%, respectively, for the three cropping seasons. Across all growing seasons and treatments, WUE_TDM values ranged between 4.11 and 6.32 Kg m⁻³. The highest values were achieved under rainfed treatment. However, no significant difference was observed between irrigated treatments, in particular, during 2022–2023 and 2023–2024. In terms of WUE_GY, no significant difference was observed between the FI and DI1 treatments, while significant reductions were registered under DI2 and DI3. The adoption of deficit irrigation at 75% ETc based on smart tensiometers can be used as an effective strategy to optimize water use in winter wheat without compromising yield. Full article

Overhead power lines are important components of power grids, and the status of transmission line equipment directly affects the safe and reliable operation of power grids. In order to guarantee the reliable operation of lines and efficient usage of the power grid, the tension of overhead power is an important parameter to be measured. The tension of power lines can be calculated from the modal frequency, but the measured acceleration data obtained from the accelerometer is severely contaminated with noises. In this paper, a multiscale-based peak detection (M-AMPD) algorithm is used to find possible modal frequencies in the power spectral density of acceleration data. To obtain a reliable noise-free signal, median absolute deviations with baseline correction (MAD-BS) algorithm are applied. An accurate estimation of modal frequencies used for tension estimation is obtained by iteration of the MAD-BS algorithm and reduction in frequency range technique. The iterative range reduction technique improves the accuracy of the estimated tension of overhead power lines. An accurate estimation of overhead power line tension can contribute to improving the reliability and efficiency of the power grid. The proposed algorithm is implemented in MATLAB R2020a and verified by comparison with measured data by a tensiometer. Full article

Biocides are often used in various industries and applications to control microbial growth and prevent the deterioration of materials, and they often have the ability to target a wide range of microorganisms rather than being specific to one type. They are designed to be highly effective at killing or inhibiting the growth of microorganisms and some biocides have residual activity, meaning they remain active for a period of time after application, providing longer-term protection. Biocides need to be compatible with the materials and surfaces they are applied to without causing damage or adverse effects, and they should remain stable under various environmental conditions, such as temperature and pH, to maintain their efficacy over time. In this study, microcapsules incorporating the biocide 4,5-dichloro-2-n-octyl-4-isotriazolin-3-one (DCOIT) were synthesized, and their effectiveness was evaluated. The investigation focused on several aspects, including colloidal chemical properties such as interfacial tension at pH values of 3, 7, and 9, as well as the size, ζ-potential, and morphology of the microcapsules. To validate the microcapsule production, elemental analysis was performed, and the effects on wettability and toxicological properties were assessed within the DCOIT + trimethoxysilyl propylmethacrylate/silicon dioxide nanoparticle system. Interfacial tension kinetics were measured using the PAT-1 tensiometer. The microcapsules exhibited an average diameter of 146 ± 1 nm following emulsification, with a ζ-potential of −50.2 ± 1 mV, as determined by the Malvern Zetasizer Nano Z. The morphology of the microcapsules was characterized using the SEM Controller 1550. Elemental composition was analyzed via energy-dispersive X-ray microanalysis (EDAX). The study concluded that the DCOIT biocide, when incorporated in the TPM/SiO₂ system, demonstrated non-toxic properties. Full article

The interaction between moisture content and soil suction is commonly represented by a soil–water characteristic curve (SWCC). The direct measurement of water content can be easily achieved, but it usually requires a destructive method where the soil sample needs to be oven-dried. Hence, indirect measurement is commonly employed for monitoring purposes. The limitation of this approach is the variability in water content at the wilting point, particularly for plants in different types of soil. While the moisture content at the wilting point varies greatly, suction at the wilting point is typically around 1500 kPa despite varying slightly depending on the type of plant. However, suction measurement using a normal tensiometer is limited to 100 kPa due to cavitation. Hence, it is not sufficient to cover up to the wilting point. The focus of this paper is the establishment of a polymer-based tensiometer utilizing a 15 bar ceramic disc for the measurement of high suction. The suitability of the polymer-based tensiometer in measuring the soil suction of vegetative soil is conducted by performing a soil–water characteristic curve test on vegetative soil. The SWCC produced from the polymer-based tensiometer is verified using SWCC produced from a centrifuge test. The results show that the SWCCs from both polymer-based tensiometer and centrifuge tests are comparable. Hence, suction measurement using a polymer-based tensiometer is deemed reliable. This advancement in suction measurement technology is crucial for improving irrigation practices, optimizing water use, and enhancing agricultural productivity, which in turn contributes to environmental sustainability by minimizing water waste and ensuring efficient soil management. Full article