Rt Values Research Articles

Using acoustic emission to understand the early-age reaction and cracking evolution of alkali-activated slag-brick powder paste

Real-time monitoring and accurately understanding the continuous occurring psychical-chemical characterization during the hardening process of alkali-activated materials present a formidable challenge. In this study, the early-age reaction process of alkali-activated slag-waste brick powder paste (ASWP) was in-situ and continuous monitored by using acoustic emission (AE) system and temperature. A novel machine learning method was employed to categorize the evolution of AE signals into three distinct stages: reaction acceleration, reaction stabilization and volume shrinkage stage.During reaction acceleration stage (0-2h), the waste brick powder (WBP) increased AE counts rate (4000-7300 counts/h), with RT values exceeding 200μs, indicating the settlement of WBP. Additionally, WBP reduced the high r-value AE activity in volume shrinkage stage, effectively mitigated the drastic volume shrinkage, and delayed its occurrence time by approximately 4 hours. Semi-quantitative analyses of FTIR and TG-DTG indicate that WBP reduced gel phase formation in the early-age stage, decreasing the relative areas in Q2 site by 16% before 36 hours. However, WBP positively impacted ASWP hydration at long ages, increasing Q2 site d areas by 60%-100%. AE technique offers a new perspective for in-depth understanding of the reaction mechanism and microstructural development of alkali-activated materials in situ and continuously.

Selective laser melting of Ti6Al4V alloy: Effects of graphene-TiO2 nanotubes composites corrosion and biocompatibility

This study investigates the effects of graphene amount on TiO2 nanotubes (TNT) synthesized on Ti6Al4V alloy via selective laser melting (SLM) to optimize corrosion resistance and biocompatibility. XRD analysis indicated the presence of anatase and rutile phases in TNTs, and the peak shifts indicated that graphene was successfully incorporated into the TNT structure. SEM images revealed that increasing the amount of graphene resulted in smaller nanotube diameters, increased contact angles, and imparted hydrophobic properties. Corrosion tests including Tafel polarization and electrochemical impedance spectroscopy (EIS) showed that graphene, especially C4-TNTs, exhibited superior corrosion resistance with high Ecorr and Rt values. Biocompatibility tests with human dermal fibroblast cells (HDFa) demonstrated cell viability with the incorporation of graphene into TNTs. The findings suggest that the optimum amount of graphene can significantly improve the corrosion resistance and biocompatibility of TiO2 nanotubes on Ti6Al4V alloy, making them more suitable for biomedical implants.

The impact of Streptococcus mutans biofilms on the color stability and topographical features of three lithium disilicate ceramics.

Secondary caries around ceramic restorations is the most common reason for the replacement of fixed dental prostheses (FDPs). Therefore, it is important to examine the susceptibility of different ceramic materials to biofilm formation. This study aimed to evaluate biofilm development and associated roughness and color alterations in three lithium disilicate ceramics: Emax CAD (EC), Emax Press (EP), and LiSi Press (LP). Streptococcus mutans biofilms were grown on the three ceramics (n = 10 per group) for 7 days. Surface roughness values and color alteration were assessed before and after the biofilm using a non-contact profilometer and spectrophotometer, respectively. Biofilm growth was evaluated using colony-forming units (CFUs) and scanning electron microscope (SEM) images. The data were analyzed using one-way ANOVA and Tukey tests. There was a significant (p≤0.001) growth of S. mutans colonies on EC (6.75 ± 0.56) and EP (6.72 ± 0.54) specimens compared to LP, which showed no biofilm growth. The change in average surface roughness (∆Ra, nm) was significantly lower (p < 0.001) in the EC specimens (0.029 ± 0.003) compared to the EP (0.055 ± 0.012) and LP (0.041 ± 0.010). When the changes in the Rv and Rt values were investigated, no significant difference was observed among the groups. Following the biofilm challenge, the change in color (∆E00) was significantly lower (p = 0.005) in the LP group (1.68 ± 1.45) compared to the EC group (3.89 ± 1.50) and no significant difference was observed between the EP group (2.74±1.01) and the other two ceramics (p ≥ 0.05). LP ceramics exhibited superior resistance to S. mutans biofilm formation and associated changes in surface roughness and color compared to the Emax CAD and Emax Press ceramics. These findings suggest that the LiSi Press material may be more favorable to mitigate the risk of secondary caries.

Comparative Evaluation of Primary Stability in Truncated Cone Implants with Different Macro-Geometries in Low-Density Polyurethane Blocks Simulating Maxillary Sinus Rehabilitations

After tooth loss, particularly in the posterior maxilla, the alveolar ridges undergo bone resorption. Therefore, ensuring the appropriate quantity and quality of alveolar bone is crucial for accurate implant positioning and achieving optimal esthetic and functional results. This study aimed to evaluate biomechanical parameters (insertion torque: IT, removal torque: RT, and implant stability quotient: ISQ) of distinct truncated cone implant designs (Sinus-plant and SLC) on polyurethane blocks simulating type D3 and D4 bone. SLC implants exhibited significantly higher IT, RT, and ISQ values compared to Sinus-plant implants, except in the 10 pounds per cubic foot (PCF) density block with a cortical layer for the IT (24.01 ± 0.91 vs. 23.89 ± 1.66 Ncm). The IT values for SLC implants ranged from 13.95 ± 0.19 Ncm in the lowest density block to 37.94 ± 0.45 Ncm in the highest density block, consistently providing significantly higher primary stability with an ISQ of approximately 70 in the highest density block. Despite lower ISQ in the lowest density block (48.60 ± 0.52 and 48.80 ± 0.42 in buccolingual and mesiodistal directions), it was deemed acceptable considering the inadequate bone densities in the maxillary region. These findings on SLC suggest potential clinical advantages, including reduced procedure duration and costs, improved stability, and the possibility of immediate implant placement following sinus augmentation, thereby streamlining the rehabilitation process.

Dense Contaminants Mixing Into the Saltwater Wedge in Coastal Aquifers: Laboratory and Numerical Investigations

AbstractThe saltwater‐freshwater mixing zones in coastal aquifers can host complex physical exchange and biogeochemical transformations. The land‐sourced dense contaminant plumes could be transferred into the mixing zone of the saltwater wedge due to the density effect prior to discharge to the sea. However, the mixing process between dense contaminants and the saltwater wedge has not received much attention, largely due to the lack of physical evidence. This study used laboratory experiments and numerical simulations to investigate the transport and discharge behaviors of variable‐density contaminant plumes in tidally influenced unconfined coastal aquifers. Results demonstrate that the highly dense contaminants mix with the underlying saltwater and finally merge with the saltwater wedge. This process significantly extends the contaminant discharge durations, thereby reducing the peak value of contaminant efflux. The dense contaminants are elongated along the landward margin of the saltwater wedge, leading to a larger spreading area (Ms) than that of constant‐density contaminants. The sensitivity analysis indicates that the high density of contaminants acts as a trigger to induce the mixing of them and wedges. The higher hydraulic conductivity, lower dispersivities and reduced inland freshwater flux significantly increase the residence times (Rt) and discharge duration (Dt) by enhancing the mixing of dense contaminants with seawater. In contrast, both Rt and Dt values are not only non‐monotonic functions of tidal amplitudes but also less sensitive to tidal effects. Compared with the non‐tidal condition, however, the addition of tides significantly increases both Rt and Ms values of dense contaminant plumes. The results presented herein provide valuable insights into the mechanisms of dense contaminants mixing into saltwater wedges, which could guide practitioners in designing effective strategies to protect coastal environments from land‐sourced contaminants.

Transmissibility of the variant of concern for SARS-CoV-2 in six regions

IntroductionDifferences in transmissibility of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) in different districts are hard to assess. To address this, our study focused on calculating the Real-time reproduction number (Rt) for these variants in different regions. MethodsAccording to the criteria defined by the World Health Organization (WHO), the global landscape was categorized into six distinct regions. In each region, the predominant SARS-CoV-2 variant was first identified based on the proportion of variant sequencing analysis results. Then, using serial interval (SI) parameters, we calculated Rt for the relevant Variant of Concern (VOC) in each region. This approach enabled us to compare the Rt values of the same variant across different regions and analyze the transmissibility of each region's variant in relation to the overall situation in that region. ResultsThe progression of VOC for SARS-CoV-2 shows regional variations. However, a common sequence of evolution is observed: Wild-type → Alpha → Beta → Delta → Omicron. Moreover, an increasing trend is discerned within diverse regions where the shift in Rt of distinct VOC corresponds with the overarching Rt route of SARS-CoV-2 in specific regions. ConclusionAs the COVID-19 pandemic advances, regional epidemiological trends are aligning, likely due to similar virus mutations and shared public health strategies, suggesting opportunities for standardized global responses.

Effects of light-emitting diodes on the morphology and accumulation of glucosinolates, carotenoids and phenolic acids in red kale sprouts

Kale (Brassica oleracea var. acephala) has gained popularity as a nutritious and phytochemical-rich vegetable. This study has investigated the effects of three LED treatments (white, blue, and red) on the accumulation of secondary metabolites in kale sprouts. Ten DAS, the kale sprouts were harvested, and growth measurements were measured. Furthermore, selected sprouts were stored at -80 °C for further biochemical analysis, namely, phenolic acids, glucosinolates, and carotenoids. Sprouts irradiated with red LED light showed the best SL, RT, and FW values. For total GSLs, we found that kale sprouts irradiated with white LED lights showed the best results (41.59±0.41 μmol/g DW). Among the aliphatic GSLs, we found that progoitrin presented the best results under blue LED light (17.93±0.49 µmol/g DW), and among the indolic GSLs, glucobrassicin showed the best results under white and red LED light. The highest concentration of total carotenoids was found in kale sprouts under white LED light exposure (3341.27±206.96 μg/g DW). Individually, β-carotene was observed in high concentration under white LED light (1935.13±87.21 μg/g DW). Among the PAs, chlorogenic acid was found in the highest concentration in the treatments under white LED light (45.78±0.73 µg/g DW). In general, kale sprouts irradiated with white LED light showed high contents of GSLs, carotenoids, and PAs. Regarding morphological characteristics, kale sprouts under red LED light showed the most promise. This research offers a valuable approach to enhancing the phytochemicals found in kale sprouting.

Effect of temperature on flexural and interlaminar shear strength properties of carbon‐epoxy composites: Experiment and modeling

AbstractCarbon fiber composites are known for excellent specific mechanical properties at room temperature. It is important to model the effect of temperature on flexural strength and interlaminar shear strength (ILSS). In this study, T700 carbon fiber composites with two different epoxy resins (Epofine, LY556) were prepared using filament winding and named as TE and TL composites. The dynamic mechanical analysis (DMA) tests revealed Tg of 177 and 192°C for TE and TL composites, respectively. Three‐point bending (flexural) and short‐beam shear (ILSS) tests were performed at −20, 0, RT, 90, 105, 150, 170, and 200°C. It was observed that flexural strength and ILSS decreases linearly with increase in temperature. Fracture analysis of flexural samples revealed fiber breakage at −20°C and micro‐buckling at elevated temperature are dominant failure mechanisms. Fracture analysis of ILSS samples showed delamination with microcracking at −20°C and plastic deformation of matrix at elevated temperature. A new empirical model was proposed to predict the temperature dependent flexural strength and ILSS. With this model, variation of flexure strength and ILSS with temperature can be estimated from respective values at RT, Tg and storage modulus values from DMA, thus extensive experimentation at high temperatures can be avoided.Highlights Mechanical properties of filament wound composites are tested from −20 to 200°C. Flexural strength and ILSS linearly decreases with increase in temperature. Fiber breakage at −20°C and micro bucking at 200°C are dominant in flexure. Delamination at −20°C and plastic deformation at 200°C are dominant in ILSS. Analytical model for finding temperature dependent flexural strength and ILSS.

Friction and wear behavior of a mechanical oscillating strip system used for interproximal enamel reduction: a quantitative and qualitative scanning electronic microscope evaluation.

To evaluate wear and friction properties of oscillating strips in order to validate the importance of a standardized interproximal enamel reduction (IPR) sequence to preserve their efficiency and lifetime. Fifteen complete oscillating IPR sequences were tested by means of tribological tests (Linear Reciprocating Tribometer, C.S.M. Instruments, Peseaux, Switzerland). Fifteen single 0.2-mm metallic strips underwent a long continuous cycle of 240 minutes. Strip surface roughness and waviness measurements were assessed by means of a contact probe surface profiler (TalySurf CLI 2000; Taylor Hobson, Leicester, UK) and TayMap software. Statistical analysis was performed with independent-samples t-test. Significance was at the P < .05 level. Scanning electronic microscopy analysis of strip surfaces was conducted with an FEI Quanta 200 (Hillsboro, Ore) in high vacuum at 30.00 kV. Resin strips revealed a significant reduction in surface roughness (Ra, Rt, RDq) and a significant increase in waviness parameters (Wa, Wt). Rt and RDq values significantly decreased upon use of the metallic strips. Significantly higher values of Wa (+ 2.84 µm) and Wt (+0.1 µm) were observed only for the 0.2-mm metallic strips. Higher friction values were observed when the metallic strips were tested singularly rather than within the entire sequence. Lower Ra and Rt values were revealed when 0.2-mm metallic strips were tested up to 240 minutes. The application of a standardized oscillating sequence allows for more efficient wear performance of the strips with a significant impact on their abrasive power and lifetime.

Multi-model fusion stacking ensemble learning method for the prediction of berberine by FT-NIR spectroscopy

Rhizoma Coptidis is a Chinese herbal medicine with antibacterial and anti-inflammatory properties. It has extensive applications in modern medicine. The content of berberine in Rhizoma Coptidis directly determines its quality. Fourier transforms near-infrared (FT-NIR) spectroscopy is a commonly used non-destructive method for rapidly detecting berberine content. In contrast to single-supervised learning algorithms in machine learning, ensemble learning combines individual learning algorithms to create a stable and better-performing strong-supervised model. This study collected spectral data of Rhizoma Coptidis using FT-NIR spectroscopy technology and established a chemometric model using a stacking ensemble approach with multiple models. Partial Least Squares (PLS), Adaptive Boosting (AdaBoost), Gradient boosting decision trees (GBDT), random forest (RF), and extreme gradient boosting (XGBoost) regression models were chosen as alternative base models, different Stacking models were established by random combinations. To fully leverage the strengths of each model and enhance predictive capability, an adaptive inertia weight particle swarm optimization algorithm (AWPSO) was used to search for the optimal parameters. The correlation coefficient of the test (RT) and the root mean square error of the test (RMSET) systematically evaluated the model performance. Finally, AWPSO-RF, AWPSO-XGBoost, and AWPSO-AdaBoost were selected as the base models. The RMSET and RT for RF, XGBoost, and AdaBoost were 0.226, 0.250, 0.195, and 0.871, 0.830, 0.927. After optimizing with the AWPSO algorithm, the RMSET and RT for AWPSO-RF, AWPSO-XGBoost, and AWPSO-AdaBoost were 0.226, 0.245, 0.194, and 0.871, 0.843, 0.922, respectively. The RMSET and RT values for the stacking ensemble were 0.174 and 0.932. The prediction accuracy and generalization ability of multi-model fusion stacking ensemble learning are superior to the single-model regression methods. Therefore, the stacking ensemble learning method that combines AdaBoost, RF, and XGBoost regression models is effective and feasible for assisting in the detection of berberine content in Rhizoma Coptidis.

Показатели нового полуколичественного экспресс-теста на прокальцитонин у пациентов с внебольничной пневмонией при наличии и отсутствии артериальной гипертензии

The presence of cardiovascular diseases can be an independent risk factor for an unfavorable prognosis of community-acquired pneumonia (CAP) and cause its erased course, which significantly complicates the timely diagnosis. It has been reported that assessment of plasma procalcitonin (PCT) levels may be useful in the differential diagnosis of lung diseases. Aim. To study the levels of a new semi-quantitative rapid PCT test (PCT RT) of plasma in therapeutic patients with CAP depending on the presence or absence of arterial hypertension (AH). Design. The simultaneous comparative study. Materials and methods. The study included 123 patients hospitalized with a diagnosis of CAP: 41 patients (mean age 69.8 ± 11.9 years) with hypertension and 82 patients (mean age 39.3 ± 16.7 years) without hypertension, who made up the comparison group. Using a new semi-quantitative RT and the method of enzyme-linked immunosorbent assay, the plasma PCT level was determined before the start of antibiotic therapy. Results. In patients with CAP and hypertension, positive PCT RT results were registered 1.8 times more often than in the comparison group — 19 (46.3%) people and 21 (25.6 %) people, respectively (p = 0.018), borderline values of PCT RT — 2.2 times more often: in 13 (31.7%) people and 12 (14.6%) people (p = 0.001) patients, respectively. The comparison group was characterized by negative PCT RT values, which were recorded in 61 (74.4%) of cases (p = 0.001). Quantitative PCT scores did not have statistically significant differences in the groups studied. In the group of patients with CAP and hypertension, positive correlations of PCT RT with body temperature (r = 0.329; p = 0.038), quantitative PCT (r = 0.505; p = 0.001), plasma glucose levels (r = 0.325; p = 0.041) and potassium (0.325; p = 0.041) were established. Conclusion. Patients with CAP and hypertension in comparison with those without hypertension are characterized by positive values of the new PCT RT, which have positive correlations with body temperature, quantitative PCT values, and plasma glucose and potassium levels. Keywords: community-acquired pneumonia, arterial hypertension, diagnostics, procalcitonin, procalcitonin rapid test.

Does Widespread Use of Hydroxychloroquine Reduce the Transmissibility of SARS-CoV-2 / COVID-19? An Ecological Correlational Study.

At the beginning of the coronavirus disease (COVID-19) pandemic, hydroxychloroquine (HCQ) was widely used as a possible antiviral agent. Current knowledge indicates that HCQ has little or no effect on individual clinical outcomes of COVID-19, but populational effects on disease transmissibility are still unknown. This study investigates the hypothesis that massive HCQ consumption by a population may contribute to reducing the transmissibility of SARS-CoV-2 and COVID-19 spread by reducing the viral load of infected individuals. Public database of seven states from Brazil in 2020 were assessed, before the start of COVID-19 vaccination. The daily values of the COVID-19 effective reproduction number (Rt) were obtained. Associations between Rt values and the proposed predictor variables (prevalence of COVID-19 as a marker of collective immunity; social isolation indices; consumption of HCQ) were tested using multiple linear regression analysis. In all seven states, consumption of HCQ was a significant negative predictor of Rt (β ranged from -0.295 to -0.502, p = 0.001). Furthermore, the mean derivative of Rt during the declining period of the COVID-19 incidence (the mean rate of variation) was also significantly negatively related to the mean HCQ consumption in that period (R2 = 0.895; β = -0.783; p = 0.011), meaning that the higher the HCQ consumption, the faster the decline of COVID-19 Rt. It suggests a dose-response phenomenon and a causal relationship in this association. The results of this study are compatible with the hypothesis that HCQ has small but significant in vivo antiviral effects that are able to reduce SARS-CoV-2 transmissibility at the populational level.

N-doped-GO@Zn nano-layers filled epoxy composite with superior mechanical and anti-corrosion properties

Fabrication of a durable corrosion-resistant epoxy coating with superior active and passive preservation features along with improved mechanical properties is the major target of this study. For this, the Nitrogen (N)-doped graphene oxide (NGO) nano-sheets were obtained in two conditions (I: plane and II: edge) and then modified with zinc ions as an inhibitor. The chemistry of the NGO-Zn nano-sheets was surveyed by FTIR and TGA methods. It was discovered from the EIS test outcomes that the entrance of 0.2 wt% of NGO-Zn nano-sheets into the epoxy coating supplied a strong protective system with considerably improved barrier properties and the emergence of active features. The hindrance properties of these nano-composite coatings were so excellent that the log |Z|10 mHz value experienced little changes even after 147 days of electrolyte attack. The active protection feature of the EP/NGOU-Zn and EP/NGU-Zn nano-containers in reference to Rt values after 48 h of immersion was concluded, displaying 1.3 and 1.7 times improvement. The Raman and FTIR test outcomes of the cured epoxy composites showed that the incorporation of fillers into the coating has no adverse effect on its curing behavior. Results disclosed that the NGO constructed with method II (NGU) greatly improved the mechanical properties of the polymeric matrix by about 50 %, recording maximum storage modulus (2021 MPa) in the dynamic mechanical thermal analysis (DMTA) test among all samples.

Occurrence conditions of the reverse rotation of rockfall and its influence on the restitution coefficient

When rockfall occurs along dense rock slopes, the rotation direction of rockfall is not always downhill. Specifically, the rockfall may obtain a reverse rotation speed (RRS) after impact under certain conditions, the effect of which on the restitution coefficient (RC) cannot be ignored. According to the statistical results of the reverse rotation (RR) phenomena of blocks obtained from previous experiments, the occurrence of RR is correlated to the block shape, incident angle, and contact attitude. In this study, considering a typically shaped cubic block, the critical condition for the RR is preliminarily deduced. Based on the results, the influence of the RRS on the RC for four typically shaped blocks is examined using a customized device. Results show that the tangential RC (Rt) values of each block are not sensitive to the change in the RRS, the distribution is relatively concentrated and the values are high. Moreover, the normal RC (Rn) values are not sensitive to the RRS, and the distribution is relatively discrete. The RRS influences Rn; however, it is difficult to directly establish the relationship between them. To this end, considering the contact attitude and shape of the block, an integral variable, the impact coefficient (Ic), is proposed to determine the influence of RRS on Rn. Moreover, the impact-bounce behaviours of the block are categorized and analysed. For the block rebound following a single impact, Ic and Rn are positively and negatively correlated when the mass centre of the block (MC) is in front and behind the contact point (CP), respectively. For the block rebound following two successive impacts, with the increase in Ic, the Rn increases. These conclusions help clarify the mechanism of the influence of the RRS on RC and provide vital information and ideas for the development and optimization of a program to accurately predict rockfall trajectories.

Analysis and Optimization of Tensile Strength for Loess Stabilized by Calcium Carbide Residue

Calcium carbide residue (CCR) can be reutilized to solidify the loess for road construction as a base or subbase due to its rich Ca(OH)2 facilitating pozzolanic reaction with water and soil particles. This study examines the effect of curing time, CCR contents, and dry unit weights on the tensile strength (Rt) of CCR-stabilized loess through the splitting tensile test. Aiming to predict the Rt values, the ratio of porosity (n) controlled by compacted effort and initial volumetric CCR content (Liv), namely n/Liv, was chosen as a prediction parameter and then modified to n/Liv0.064 for compatible variation rate with Rt values. A prediction model for the splitting tensile strength of CCR-treated soil was proposed considering the modified ratio n/Liv0.064 and curing days. The results indicate that Rt values showed a nearly linear positive correlation with CCR contents and dry unit weights, logarithmic increase with the extension of curing time, but no apparent relationship with the ratio n/Liv. The modified ratio n/Liv0.064 can reflect the trend of Rt values at different curing days since the coefficients of determination were almost greater than 0.90 except for the specimens cured for seven days. The proposed prediction model had a good fit for laboratory data with 97% acceptability and close to 3% error. It can be applied for estimating the Rt values of CCR-stabilized loess using curing time and an optimized ratio of porosity and initial volumetric CCR content. From the aspect of practical engineering, the reutilization of CCR can reduce construction costs, waste disposal costs, and environmental pollution.

Clean fabrication strategy of diamond crystals containing nanocomposite films for corrosion and wear protection of AISI-321 alloy

This study focused on the synthesis of Niobium/Hexagonal-Diamond/Amorphous-Carbon (Nb/H-D: a-C) films on AISI-321 alloy. The substrate heating used as a vital deposition parameter to tailor structure of the films in an unbalanced magnetron (UB-M) sputtering system for the first time. The substrate heater temperature (Th) ranged between (RT) to 150 °C. The results indicated that increasing the substrate heater temperature promoted the abundance of hexagonal diamond (H-Diamond) crystals through the solid phase separation. Therefore, the film deposited at the highest temperature (150 °C) demonstrated the highest plenty of H-Diamond. Electrochemical impedance spectroscopy (EIS) measurements (after 2, 8, 24, 72, and 168 h immersion) and polarization tests (after 168 h immersion) disclosed that increasing the substrate heater temperature positively affects the corrosion resistance of (Nb/H-D: a-C) films. The results proved that the film deposited at the highest temperature of 150 °C, demonstrated the exceptional corrosion protection efficiency of 99.69 %. Moreover, this film presented acceptable low-frequency impedance (|Z|10KHz) and total resistance (Rt) values of >108 Ω·cm2 and >117 MΩ·cm2 at all immersion times in 3.5 wt% NaCl solution. The highest abundance of the H-Diamond phase, with remarkable chemical inertness at higher substrate heater temperatures, can be an effective reason for elevating anti-corrosion performance of the films. Additionally, as the substrate heater temperature enhanced from RT to 150 °C, mechanical properties illustrated an remarkable increment trend (increasing hardness from 20 to 32.7 GPa and the elasticity modulus from 407 to 470 GPa). Moreover, the anti-wear performances of the films significantly improved with increasing substrate heater temperature, reducing the wear rate from 9.4 × 10−6 to 9 × 10−7 mm3/N·m. These results are mainly attributed to the highest abundance of the superhard H-Diamond phase in the film deposited at higher substrate heater temperature. In conclusion, the (Nb/H-D: a-C) film synthesized at 150 °C represented a promising candidate for tailoring the electrochemical and anti-wear performances of AISI-321 alloy.

Eupatorium adenophorum Spreng leaves extract/potassium iodide as a highly sustainable inhibitor for the corrosion protection of steel in citric acid solution

Plants extract inhibitor has the standout merits of low-cost, eco-friendly and rich natural raw resources. The synergism between Eupatorium adenophorum Spreng leaves extract (EASLE) and KI for the corrosion of cold rolled steel (CRS) in citric acid (H3C6H5O7) solution was tested in detail by weight loss and electrochemical techniques. The micro-morphology of CRS surface was fully characterized by both scanning electron microscope (SEM) and atomic force microscope (AFM). Fourier transform infrared spectrometer (FTIR) and high performance liquid chromatography (HPLC) were employed to deeply analyze the main bio-active components in EASLE. The results show that either EASLE or KI can moderately inhibits the corrosion of CRS, and their maximum inhibition efficiency values are below 75%. As EASLE is combined with KI, their mixture has a better inhibition of over 90%. There is a synergism between EASLE and KI, and the corresponding synergism parameters are all higher than unity with a highest value of 3.5 for 400 mg L-1 EASLE/ 100 mg L-1 KI at 60 °C. The adsorption of EASLE, KI or EASLE/KI mixture follows Langmuir isotherm, and the adsorption is strengthened for the synergistic mixture. EASLE mainly retards the anodic reaction, while EASLE/KI mixture drastically inhibits both cathodic and anodic reactions simultaneously with a low corrosion current densities of 17.8 µA cm−2. Nyquist graph appears a depressed capacitive loop at high frequencies followed by an inductive loop at low frequencies. EASLE/KI mixture has larger charge transfer resistance (Rt) comparing with either EASLE or KI. Rt values for 500 mg L-1 EASLE, 100 mg L-1 KI and 500 mg L-1 EASLE/100 mg L-1 KI mixture are 464.9, 382.9 and 1068 Ω cm2, respectively. SEM and AFM micro-images clearly confirm that the corrosion extent as well as surface roughness of CRS surface were sharply dropped after adding EASLE/KI mixture. The main bio-active components in EASLE are phenylpropanoids like chlorogenic acid, caffeic acid and ferulic acid.

Engineering a novel smart nano-carrier based on NH2-MIL-125 metal-organic framework (Ti-MOF) decorated 2D GO nano-platform for reaching a self-healing coating

In this research, for the first time, sodium gluconate (SG) and zinc nitrate hexahydrate (Zn) were effectively inbuilt into NH2-MIL-125 (Ti) decorated graphene oxide (GO) nanolayers and then embedded into an epoxy coating (EP) to create an active (self-healing)/passive (barrier) anti-corrosion organic coating system. Various experiments were conducted to determine the characteristics of the synthesized nanomaterials. In addition, electrochemical impedance spectroscopy (EIS) techniques were used for the solution-phase study and exhibited 88% inhibitory efficacy for GO@MOF/SG-Zn. Moreover, the EIS test demonstrated that incorporating GO@MOF/SG-Zn into the EP enhanced its self-healing and barrier abilities. The total resistance (Rt) values of 636.14 KΩ.cm2 were obtained from the scratched EP-GO@MOF/SG-Zn sample, whereas the highest Rt values for the scratched EP and EP-GO were 91.25 and 76.78 KΩ.cm2, respectively. Also, after 84 days, the impedance value for the EP-GO@MOF/SG-Zn reduced to 10.51 Ω.cm2, which was a minor decrease among the examined samples.

Application of Bio-Inspired Gold Nanoparticles as Advanced Nanomaterial in Halt Nociceptive Pathway and Hepatotoxicity via Triggering Antioxidation System

This study aimed to investigate the pharmacological efficacy of gold nanoparticles (GNs) synthesized using a green route, employing the rhizome extract of Euphorbia wallichii (REEW) as a bioreductant and surface stabilizing agent. The GNs were characterized by a series of complementary analytical techniques including SEM-EDX, XRD, DLS, and IR spectroscopy. The reducing ability of REEW and synthesis of GNs were confirmed using UV–visible absorption spectroscopy, and the presence of spherical GNs with an fcc geometry was further confirmed through SEM and XRD analyses. The role of REEW’s extract as a stabilizing agent towards GNs was verified through FTIR and electronic absorption spectral measurement. The GC-MS analysis showed the presence of 41 different phytochemicals in REEW (chloromethyl 2-chloroundecanoate; cortisone; benzo[h]quinolone; piperidine, 2,4-dimethyl- 3,6,7-trimethoxyphenanthroindolizidine; 4-methyl-; 2-[2-quinolylmethyleneamino]ethanol, etc.), with RT values ranging from 3.10 to 27.22 min. The REEW-functionalized GNs exhibited promising antioxidant efficacy against H2O2 and *OH used as probe molecules. DPPH scavenging test showed significant EC50 values of 19.47 µg/mL, 13.53 µg/mL, and 10.57 µg/mL at 30, 60, and 90 min of incubation, respectively. Thermal nociceptive mice significantly acquired analgesia in a dose-dependent manner. Moreover, pre-treatment with REEW-GNs significantly restored serum ALT, AST, ALT, T.P, and Bilirubin levels in PCM-intoxicated mice. The antidiabetic activity in alloxan-induced diabetic rabbits fell in orders of metformin &gt; GNs 300 mg/kg b.w &gt; GNs 200 mg/kg b.w &gt; GNs 100 mg/kg b.w &gt; saline at 0.1 h of drug administration. To sum up, REEW functionalized GNs have tremendous potential for curing degenerative/metabolic diseases caused as a result of oxidative stresses.

Influence of surface characteristics of implant materials on MRSA biofilm formation and effects of antimicrobial treatment.

One of the main causes of treatment failure in bacterial prosthetic joint infections (PJI) is biofilm formation. The topography of the biofilm may be associated with susceptibility to antimicrobial treatment. The aims of this study were to assess differences in topography of biofilms on different implant materials and the correlation thereof with susceptibility to antimicrobial treatment. Methicillin-resistant Staphylococcus aureus (MRSA) 7-day mature biofilms were generated on disks made from titanium alloys (Ti-6Al-7Nb and Ti-6Al-4V), synthetic polymer and orthopedic bone cement, commonly used in implant surgery. The surface topography of these implant materials and the biofilms cultured on them was assessed using atomic force microscopy. This provided detailed images, as well as average roughness (Ra) and peak-to-valley roughness (Rt) values in nanometers, of the biofilm and the material surfaces. Bacterial counts within biofilms were assessed microbiologically. Antimicrobial treatment of biofilms was performed by 24-h exposure to the combination of rifampicin and ciprofloxacin in concentrations of 1-, 5- and 10-times the minimal bactericidal concentration (MBC). Finally, treatment-induced differences in bacterial loads and their correlation with biofilm surface parameters were assessed. The biofilm surfaces on titanium alloys Ti-6Al-7Nb (Ra = 186 nm) and Ti-6Al-4V (Ra = 270 nm) were less rough than those of biofilms on silicone (Ra = 636 nm). The highest roughness was observed for biofilms on orthopedic bone cement with an Ra of 1,551 nm. Interestingly, the roughness parameters of the titanium alloys themselves were lower than the value for silicone, whereas the surface of the bone cement was the roughest. Treatment with 1- and 5-times the MBC of antibiotics resulted in inter-material differences in colony forming units (CFU) counts, ultimately showing comparable reductions of 2.4-3.0 log CFU/mL at the highest tested concentration. No significant differences in bacterial loads within MRSA biofilms were observed between the various implant materials, upon exposure to increasing concentrations of antibiotics. The surface parameters of MRSA biofilms were determined by those of the implant materials on which they were formed. The antibiotic susceptibility of MRSA biofilms on the various tested implant materials did not differ, indicating that the efficacy of antibiotics was not affected by the roughness of the biofilm.