Peak Intensity Research Articles

Solid-state solvatochromism of oxazolidine in multi-functionalized copolymer nanoparticles: Development of advanced materials with multi-color fluorescence

Investigating the solvatochromism of stimuli-chromic compounds such as oxazolidine in polymer matrices with various polarities or functionalities is a unique approach to developing advanced materials for anticounterfeiting, sensor, optoelectronic, and displayers. In a novel strategy, multi-functionalized copolymer nanoparticles were synthesized by copolymerization of methyl methacrylate (MMA) with various functional comonomers in emulsion media for post-polymerization modification with oxazolidine and investigation of its solvatochromism in both colloidal solution and solid phase. The particle size and morphology of nanoparticles were influenced significantly by the polarity of functional groups, and the morphology evolution from sphere to anisotropic shapes was observed by increasing the polarity of functional groups. Investigation of oxazolidine solvatochromism in colloidal solution and solid polymer powders indicated different mechanisms for solvatochromism, in which the polarity of media is the main effective parameter in colloidal solution and the polarity of functional groups in the polymer structure is the main effective parameter in solid polymer phase. The solvatochromism of oxazolidine was confirmed by observed red shift and blue shift in UV–Vis and fluorescence spectra, in which the intensity of absorbance and emission peaks was changed as a function of the polarity of functional groups. Solvatochromic photoluminescent polymer nanoparticles were used for several advanced applications such as solid anticounterfeiting inks to information encryption, dual-mode visualization of latent fingerprints, and also development of organic light-emitting diodes (OLEDs). For the first time, the results indicate a significant effect of polymer chain local polarity induced by functional groups on the tuning of optical properties of the oxazolidine by the solid-state solvatochromic phenomenon. Solvatochromism of oxazolidine in functionalized polymer nanoparticles is an interesting approach to developing novel intelligent materials that have advanced applications in different fields such as anticounterfeiting and information encryption, optoelectronic, polarity sensor, and visualization of latent fingerprints.

Synthesis, characterization, and study of linear and non-linear optical properties of some newly thieno[2,3-b]thiophene analogs

Abstract Newly 3,4-Diaminothieno[2,3-b]thiophene derivatives were synthesized by attaching with different aromatic have rich electron. The resulted compounds have been investigated by FT-IR, NMR, elemental analysis, and optical absorption spectra. Comparison between these resulted compounds revealed oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene has the highest absorption peak intensity at ~ 696nm, thin films have been prepared by thermal evaporation technique and characterized by UV-Visible-NIR spectroscopy as well as the allied absorption, dielectric and dispersion parameters have been investigated and compared with other reported results. Obtained results indicated diethyl 3,4-bis(((E)-2-oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene-2,5-dicarboxylate and 3,4-bis(((E)-2-oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene-2,5-dicarbonitrile have manifested small band energy gap energy 1.95, 1.66 eV; respectively as a result of increasing conjugation and high absorption coefficient, make these compounds ideal for use in solar cell. The high nonlinear parameters such as refractive index and third-order nonlinear susceptibility of these organic compound thin films are significantly asymptotic compared with chalcogenide and oxide materials, making them suitable for nonlinear optical devices.

Novel Ratiometric Surface-Enhanced Raman Scattering (SERS) Biosensor for Ultrasensitive Quantitative Monitoring of Human Carboxylesterase-1 in Hepatocellular Carcinoma Cells Using Ag-Au Nanoflowers as SERS Substrate.

In this study, we developed ratiometric surface-enhanced Raman scattering (SERS) biosensors using Ag-Au alloy nanoflowers as SERS substrates, molecules having amide bonds and alkyne groups (Tag A) as Raman reporters, and sodium thiocyanate as an internal standard molecule (Tag B) for the sensitive detection of human carboxylesterase-1 (hCE1) in HepG-2 cells. The correlation between HepG-2 cell damage and hCE1 activity levels was investigated. Both Tag A's alkyne group and Tag B's cyanide group produced characteristic SERS signals in the Raman-silent region (I2000cm-1 and I2115cm-1, respectively). The hydrolysis of the amide bond in Tag A via hCE1 and the shedding of the alkyne group led to a reduction in the SERS signal intensity observed at I2000cm-1. Conversely, the SERS signal intensity of Tag B at I2115cm-1 exhibited a consistent pattern. As the activity level of hCE1 and the ratiometric peak intensity (I2000cm-1/I2115cm-1) correlated negatively, hCE1 could be quantitatively detected within the range of 10-2 to 2 × 102 ng·mL-1, with a detection limit of 7.3 pg·mL-1. The ratiometric SERS probe strategy, in which a ratio response is employed, permits sensitive and reproducible SERS detection by facilitating intrinsic calibration to rectify signal fluctuations resulting from temporal and spatial variations in the detection conditions. Concurrently, the implementation of Raman-silent region reporter molecules mitigates the interference from endogenous biomolecules in SERS measurements and offers a novel approach for achieving highly sensitive and interference-free detection of intracellular hCE1.

Distinguishing and Further Reinforcement for Nanocrystal XRD Peaks Caused by Instrument Broadening in Nanomixed Materials

X-ray diffraction (XRD) is one of the most essential techniques for characterizing various crystals. However, when nanocrystals are present, the diffraction peaks become significantly broadened and reduced in intensity, making phase and microstructure analysis challenging. To obtain more refined microstructural information from nanocrystals, various methods have been developed to enhance diffraction peaks, with step scanning being a commonly used approach. Additionally, increasing instrument broadening (IB) by adjusting slit sizes to enlarge the irradiation area is a convenient yet often overlooked method. In this study, the effects of IB on the diffraction peak intensities of nanocrystals and micron crystals in mixed materials were thoroughly investigated. The results show that the intensities of both nanocrystals and micron crystals increase as IB increases, a behavior similar to that observed when extending the testing time during step scanning. However, the rate of increase in peak heights for nanocrystals is higher than for micron crystals, while the rate of increase in peak width for nanocrystals is lower, which is a significant departure from the effects seen in step scanning. In other words, nanocrystal peaks become sharper and more distinct as IB increases. This phenomenon is explained by the different components of peak width for nanocrystals and micron crystals, based on Lorentz mathematical model analysis. Based on these findings, it is recommended to utilize larger IBs in combination with step scanning to further reinforce nanocrystal peaks in mixed materials.

Contrast-enhanced ultrasound can differentiate the level of glioma infiltration and correlate it with biological behavior: a study based on local pathology.

The objective of this study is to assess the diagnostic efficacy of contrast-enhanced ultrasound (CEUS) in determining the level of glioma infiltration and to investigate its correlation with pathological markers. A prospective study involving 16 adult glioma patients was conducted. Preoperative US-(Magnetic Resonance)MR fusion imaging was utilized for tumor infiltration localization, while CEUS was employed to assess hemodynamic alterations. Parameters such as peak intensity (PI), rise time (RT), time to peak (TTP), and area under the curve (AUC) were measured. Utilizing contralateral normal brain tissue as the reference standard. The Kruskal-Wallis H-test was conducted to compare CEUS and pathological parameters (significance level, p < 0.05; bonferroni correction) among tumor margins, infiltration zones, and normal tissues, as well as between low-grade glioma (LGG) and high-grade glioma (HGG) within the infiltration zone, based on whole slide pathological images analysis. Spearman correlation analysis was employed to determine the correlation coefficient between hemodynamics and pathology. Receiver operating characteristic (ROC) curves were drawn to evaluate the performance of CEUS in tumor classification. From tumor margin to normal tissue, PI, AUC, Ki67, EGFR, and 1p/19q showed a significant decreasing trend, while TTP, IDH-1, and MGMT gradually increased. RT was lower at the tumor margin but did not show statistically significant differences. In the infiltration zones, there was a significant increase in parameters such as PI, normalized PI (Nor_PI), AUC, and Ki67 from LGG to HGG, while RT, Nor_RT, TTP, Nor_TTP, IDH-1, and MGMT significantly decreased. Nor_AUC and EGFR increased but were not significant, and 1p/19q decreased but was not significant. RT and Nor_TTP were independent risk factors for distinguishing between LGG and HGG in the infiltration zone, with a combined diagnostic efficacy ROC of 0.891. The sensitivity reached 96.64% and the specificity reached 82.35%. There was a significant correlation between hemodynamic indicators and pathological indicators. CEUS can effectively differentiate levels of infiltration zones, which correlates with their biological behavior, with RT + Nor_TTP showing particularly highest diagnostic efficacy. These findings contribute to improving the accuracy of diagnosing infiltration zones and provide essential biological insights for subsequent treatments.

Crotalaria madurensis flavonol glycosides’ antibacterial activity against Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infections are prevalent in hospitals and often lead to significant health complications. This study aimed to explore the chemical composition of the aerial part of Crotalaria madurensis and evaluate its antioxidant and antibacterial properties. The impact of gamma irradiation on the antibacterial properties of the plant extract and metabolite 1 against MRSA was also examined. Fourier-transform infrared (FTIR) analysis was conducted on the filtrates of untreated MRSA and MRSA treated with the plant extract and metabolite 1. Four flavonol glycosides were identified as gossypetin 8-methoxy, 3-O-β-D-xylopyranoside (metabolite 1), gossypetin 8-O-β-D-glucopyranoside (metabolite 2), kaempferol 3-O-β-D-glucpyranoside (Astragalin, metabolite 3), and herbacetin 7-methoxy-3-O-β-D-glucopyranoside (metabolite 4). All metabolites exhibited significant antioxidant properties using different assays. The antibacterial efficacy of the extract and metabolite 1, which showed substantial antioxidant properties compared to the other isolated metabolites, was evaluated. Both the plant extract and metabolite 1 significantly reduced the viability and cell count of MRSA at concentrations of 1.0 and 0.5 mg/ml. The antibacterial activity of the plant extract and metabolite 1 was assessed after gamma irradiation at 50 and 100 Gy, which did not significantly affect the antibacterial efficiency. FTIR analysis indicated that the plant extract and metabolite 1 significantly altered the band frequency values, bandwidth, and peak intensity % of the treated MRSA filtrate. Molecular docking studies suggested that metabolite 1 exhibited the highest antioxidant and anti-MRSA activity, with strong binding scores like the ligand, indicating an effective interaction and high affinity between metabolite 1 and the target molecule.

Chlorophyll films for radiation dosimetry: a feasibility study

Abstract Novel Chlorophyll-PVA composite films have been prepared and tested for the dosimetry of therapeutic radiation. The radiation response has been quantified using UV–vis spectroscopy. FTIR and XRD spectroscopies have been used to characterize the physical properties and irradiation response of the films. The films have shown response towards the therapeutic x-rays beams of 6 MV nominal energy in the tested dose range of 0.25 Gy to 32 Gy in discrete dose levels occurring in the geometric progression series of 2. The dosimeter has been found to exhibit sensitivity at a low dose of 0.25 Gy. The dose response curve of the dosimeter exhibits an exponential relationship of the absorbance and absorbed dose. A region of saturated absorbance has been observed beyond 4 Gy. The peak intensities of the FTIR spectra have been found to decrease with increasing doses as compared to the unirradiated samples, because of the changes in the bond polarities and molecular geometries. The XRD spectra indicates a change in the molecular orientation resulting in a decrease in peak intensity with increasing dose. This study indicates the feasibility of chl-PVA films in the dosimetry of therapeutic radiation. This film dosimeter can be processed locally with minimum resources and standardized against a known standard before clinical use. The chlorophyll molecules need careful handling owing to their sensitivity to light and temperature.

Time-Trend Analysis and Risk Factors for Niraparib-Induced Nausea and Vomiting in Ovarian Cancer: A Prospective Study.

Nausea and vomiting are major non-hematological adverse events associated with niraparib maintenance therapy. This study aimed to investigate the time-trend patterns of niraparib-induced nausea and vomiting (NINV) and the associated risk factors in patients with ovarian cancer. In this prospective study, we enrolled patients with stage III-IV epithelial ovarian cancer who received niraparib as frontline maintenance therapy. The clinicopathological characteristics and time-trend patterns of patients with NINV were collected through in-person surveys and electronic medical records from the National Cancer Center. Of 53 patients, 50 (94.3%) were diagnosed with high-grade serous ovarian carcinoma. BRCA mutations and homologous recombination deficiency (HRD) were identified in 23 (43.4%) and 32 (60.4%) patients, respectively. Thirty-one patients (58.5%) had NINV. Time-trend analyses revealed that the first peak intensity of NINV was reached at 3 h post-dose, and the second peak intensity was reached at 11 h post-dose. NINV significantly decreased from week 1 to weeks 8 and 12. In multivariate analyses of risk factors for NINV, HRD-positive tumors (p<0.001) and prior experience of chemotherapy-induced nausea and vomiting (p=0.004) were associated with the occurrence of NINV. Pre-emptive treatment with antiemetics are required to manage early-phase NINV during niraparib maintenance therapy in patients with risk factors. Additional larger studies are needed to confirm these findings and to develop optimal preventive strategies for NINV.

Preparation of chlorinated polyethylene/carbon black/benzoxazine composites with positive temperature coefficient effects

Chlorinated polyethylene (CPE)/carbon black (CB)/ benzoxazine composites with Positive Temperature Coefficient (PTC) characteristics are prepared using the conventional melt-mixing method. The research investigates how benzoxazine content and curing time impact the PTC/NTC characteristics, resistivity, microstructure, and crystallization behavior of these composites.The findings demonstrated a positive correlation between the room temperature resistivity of CPE/CB/benzoxazine composites and benzoxazine content, making the control of benzoxazine content particularly important. Scanning electron microscopy (SEM) reveals that these composites maintain a porous isolated structure regardless of curing time. However, crystallinity decreases as curing time increases. Optimal conditions are achieved with benzoxazine concentration of 2 wt% and a curing time of 45 minutes, resulting in a PTC intensity peak exceeding 5 after R-T cycling. Additionally, at 2 wt% benzoxazine content and a curing time of 60 minutes, a three-dimensional cross-linked network is formed. This network confines carbon black within specific regions, preventing large-scale aggregation and eliminating the NTC effect. After three thermal cycles, the PTC intensity stabilizes around 3.8, indicating good cycling stability.

Numerical Investigation of Burial Depth Effects on Tension of Submarine Power Cables

To protect submarine power cables from damage caused by anchoring and fishing, submarine power cables in shallow water areas are buried to a certain depth through a cable laying machine. However, limited attention has been paid to studying the stress behavior of submarine power cables while considering the effects of burial depth. In this research, static and dynamic analyses are carried out using three-dimensional numerical models performed by the OrcaFlex v11.0 to investigate the effects of burial depths on cable tension during the cable installation under various conditions. Numerical simulation results show that the peak tension of the submarine power cable increases linearly with the increase in burial depth. In addition, the burial depth can also change the tension state at the endpoint of the submarine power cable. The endpoint of the cable is in a compressed state when h &lt; 2 m and the cable turns into a tensile state when h ≥ 2 m. Finally, genetic programming (GP) is used to analyze numerical simulation results to propose a prediction model that can be used to estimate the peak tension of the submarine power cable during cable installation under various burial depths in shallow sea areas. It should be noted that the proposed GP model is based on the analyses of numerical results; therefore, the GP model is open for further improvements as more experimental data become available.

Exploring Storm Intensities and the Implications on Green Stormwater Infrastructure Design

ABSTRACTThe peak intensity that occurs during a storm event can drive the performance of a green stormwater infrastructure (GSI), which may or may not align with the expected performance of the GSI. Both the peak intensity volume and where it occurs within an event are found to influence the GSI response. The design criteria set the expectation of how well a GSI will manage stormwater within a watershed. The Villanova University bioinfiltration rain garden (BRG) has been monitored since 2003, providing a long hydrological data record that is used to study local and observed rainfall patterns in comparison to design criteria to understand the impact of storm intensity on GSI performance. Intensities for all the storms recorded at the site were assessed at different timesteps and compared to the intensities typically used by the design storm approach in meeting regulatory criteria. There were 1482 storm events analysed and for all timesteps, the values commonly used for meeting design regulations were seen to be well above what was observed at the BRG, with 98% of the storms occurring below these values. Out of the 1482 storms, only 46 storms (3%) had effective durations longer than 10 h and no storm observed had an effective duration longer than 22 h, yet their peak intensities were still below the peak intensity associated with design regulations. This finding highlights the difference in the duration these sites are designed to manage (typically 24 h), in comparison to the ones experienced by the systems. The peak intensity analysis done at the different timesteps shows that for the storms recorded at the BRG, the intensities vary with changing time intervals and events. Of all the assessed events, only two events recorded larger intensities than the regionally specified NOAA C design storm, demonstrating the skewness of the approach. There was no trend in peak rain intensities over the 20‐year rainfall record. This study concludes that due to their dynamic performance, vegetated GSI have a natural resilience to a variety of precipitation patterns and climate changes that may be compromised when designing to a static value set through design storms.

The Impact of π-Bridge Moiety on the Optoelectronic Properties and Photochemical Stabilities of Benzodithiophene-Based Conjugated Polymers

The stability of conjugated polymers (CPs) under exposure to light and air determines their sustainability for commercial use and their possible usage in diverse areas. The main goal of this study is to examine how changes in the π-bridge of polymers affect their electrochemical and optoelectronic properties. Furthermore, it seeks to evaluate the impact of these alterations on the photochemical durability of the polymers. Three D-π-A types of CPs were synthesized via Stille coupling. All polymers consist of the same acceptor and donor units, which were benzooxadiazole (BOz) and benzo[1,2-b:4,5-b']dithiophene (BDT), respectively, but they had different π-bridge such as thiophene (T), selenophene (Se), and thiazole (Tz).This study used a variety of spectroscopic tools such as UV-Vis, FTIR, and XPS, to investigate how photooxidation occurs. DFT calculations were used to further support the experimental results. Within a mere 30-minute timeframe, the primary absorption peak of the polymer films experienced a blue shift and a significant reduction in intensity due to being exposed to both light and air simultaneously. Despite the presence of the same electron-withdrawing group, BOz, and electron-donating group, BDT, in all polymers, the photochemical stability varies with π-bridges. T- and Se-containing conjugated polymer films (P1-T, P2-Se) exhibited a significant decrease in the intensity of their peak absorption, whereas the peak intensity and characteristics of their thiazole counterpart (P3-Tz) only showed a slight alteration after being exposed to light and air for up to 7 hours. The superior photostability of the P3-Tz polymer film can be attributed to a significantly higher HOMO level and higher band gap in comparison to P1-T and P2-Se.Comprehending the photochemical stability of these polymers is crucial for progressing their commercial uses, such as organic photovoltaics, OLEDs, and sensors. This study highlights the significance of choosing suitable π-bridges to improve the longevity and effectiveness of CPs, thus satisfying market requirements and broadening their possible applications.

Image of the Kerr–Newman Black Hole Surrounded by a Thin Accretion Disk

The image of a Kerr–Newman (KN) black hole (BH) surrounded by a thin accretion disk is derived. By employing elliptic integrals and ray-tracing methods, we analyze photon trajectories around the KN BH. At low observation inclination angles, the secondary image of particles is embedded within the primary image. However, as the inclination increases, the primary and secondary images separate, forming a hat-like structure. The spin and charge of the BH, along with the observer’s inclination angle, affect the image’s asymmetry and the distortion of the inner shadow. To investigate the redshift distribution on the accretion disk, we extended the inner boundary of the accretion disk to the event horizon. The results show that the redshift distribution is significantly influenced by the observation inclination angle. Furthermore, we conducted a detailed analysis of the KN BH image using fisheye camera ray-tracing techniques and found that the optical appearance and intensity distribution of the BH vary at different observation frequencies (specifically at 230 GHz and 86 GHz). We also examined differences in intensity distribution for prograde and retrograde accretion disk scenarios. Comparing observational at the two frequencies, we found that both the total intensity and peak intensity at 86 GHz are higher than those at 230 GHz.

Electrochemical investigations of decorated graphite felt electrodes with Nafion/TiO2 nanoparticles for vanadium redox flow battery: Improving electro-catalytic characteristics

The present study aimed to investigate the effect of Nafion/TiO2 nanoparticles as an electrocatalyst on the electrochemical behavior of graphite felt (GF) electrodes in a vanadium redox flow battery. Various electrochemical tests, including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV), were conducted to assess the performance of these electrodes at different concentrations of nanoparticles (2-4 g L-1). Additionally, X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy were employed to analyze the chemical composition, bonding, and morphology of the decorated electrodes, respectively. The CV results revealed several effects of TiO2 nanoparticles on the GF electrode, such as increased peak intensity and shifted peak sites. As the concentration of nanoparticles increased, the peak intensity rose by up to 44%. Moreover, the potentials of the decorated electrodes shifted towards the favorable side compared to the GF electrode, with changes ranging from 18 to 84%. Overall, the optimal concentration of TiO2 nanoparticles (3 g L-1) exhibited excellent electrode performance, characterized by the highest calculated diffusion coefficient, greater reversibility, enhanced electron transfer kinetics, improved stability, lower over-potential, and the lowest activation energy for redox reactions. EIS results demonstrated a significant decrease in polarization resistance (67.2-70.8%) for the decorated electrodes. Furthermore, LSV measurements indicated that the utilization of nano-electrocatalysts effectively inhibited hydrogen evolution at negative potentials.

An investigation of n-type semiconductors based on optical and photoluminescence of pure and Al doped Pr:123 compound

With ZnO comparison, we report here an investigation of n-type semiconductors in terms of optical and photoluminescence (PL) analysis based on PrBa2Cu3-3xAl3xOy (AlPr:123) compound with (0.00 ≤ x ≤ 1.00). The structure is tetragonal of the samples with x ≤ 0.30 and changes to orthorhombic for x > 0.30, whereas it is wurtizite (hexagonal) for ZnO. As x increases to 1.00, the grain size is decreased, while the crystallite size and porosity are increased, but they are comparable with those obtained for ZnO. The Debye temperature, Young’s modulus and energy gap are drastically decreased by increasing x until reach to their maximum values of 623.14 K, 952 GPa and 3.45 eV for x = 1.00 (650.39 K, 17 GPa and 3.28 eV for ZnO). The x = 0.05 has increased the carrier density to 8.06 × 10 19 (cm−3), which is about 8-times higher than of ZnO (1.07 × 10 19 (cm −3). The highest value of q-factor (3.5 × 10 5) is obtained for x = 0.00, which is about 10-tims higher than of ZnO (3 × 10 4). As x increases above 0.30, the optical conductivity is significantly increased to be greater than that of ZnO. The PL intensity of the visible emission peaks was gradually increases against x until becomes higher than that of ZnO when x = 1.00. A slight UV shift is obtained for x ≤ 0.30 samples, but it changed to blue for x ≥ 0.60, which is typically similar to ZnO. As compared to ZnO, the present samples are strongly recommended for plastic deformation, solar cell, light emission, super-capacitor and high-power operation. To the best of our knowledge, the present work has never been done elsewhere.

Synthesis and Characterization of Polyaniline/TiO2 Nanocomposite based Ammonia Gas Sensor

Pure TiO2 nanoparticles were synthesized using the sol-gel method and polyaniline (PANI), while PANI/TiO2 (content TiO2:25% and 50%) nanocomposites were synthesized by using in-situ chemical oxidative polymerization method. X-RD, FTIR spectroscopy, and scanning electron microscopy (SEM) were used for the structural analysis, elemental composition, and surface morphology. The XRD patterns of PANI/TiO2(25%,50%) composites reveals that the relative intensity of diffracted peaks increases with increasing the content of TiO2 indicating an increase of crystallinity in such case. FTIR confirmed the presence of functional groups in the nanocomposite. In SEM surface morphology observed that highly porous nanograins are formed. The average particle sizes of PANI/TiO2(25%) 339 nm and PANI/TiO2(50%) 196 nm were obtained. The resistance change response of nanocomposite material were done by using a static two-probe unit by exposure to ammonia (NH3) gas. The maximum sensitivity of PANI/TiO2(50%) nanocomposite was achieved on 500 ppm (parts per million) of ammonia gas at 40°C. The fast response time (20 sec.), and recovery time (28 sec.) has obtained.

A novel dual-function fluorescence sensor Eu/CDs@MOF-808 for the sensitive detection of adenosine triphosphate and uric acid

Designing and developing a reliable method for the detection of potential biomarker molecules are crucial for the early prevention and diagnosis of diseases. In this study, we present a novel functionalized metal–organic framework material (MOF-808) that is developed to construct ratiometric fluorescence sensing platforms (Eu/CDs@MOF-808) for the detection of adenosine triphosphate (ATP) and uric acid (UA). The fluorescent probe Eu/CDs@MOF-808 prepared through the in-situ encapsulation of fluorescent carbon dots (CDs) within the structure of MOF-808 exhibits excellent optical properties. Additionally, rare earth ions (Eu3+) are incorporated into the CDs@MOF-808 using a post-synthetic modification strategy. The presence of ATP significantly enhances the characteristic peak of carbon dots (CDs) at 440 nm, while the peak of Eu3+ at 614 nm remains relatively unchanged. Furthermore, the concentration of ATP exhibits a strong linear relationship with the ratiometric fluorescence intensity (F440/F614) in the concentration range of 0.5–450 μM, with a detection limit of 0.22 μM. Notably, the addition of uric acid (UA) to this fluorescence sensing platform leads to a marked reduction in the characteristic peak intensity of Eu3+, which results in a satisfactory linear relationship between the ratiometric fluorescence intensity and UA concentration in the concentration ranges of 0.04–300 μM and 300–650 μM, with a detection limit of 0.04 μM. Additionally, the fluorescent sensor has been successfully applied for the detection of ATP and UA in real serum and urine samples.

Effect of sodium gluconate addition on setting, hardening, and microstructure behaviour of hybrid alkaline mortar

In this investigation, the influence of adding 2%, 4%, 7%, and 10% sodium gluconate (SG) on the setting time of hybrid alkaline paste, and hardened and microstructure properties of hybrid alkaline mortar mixes were examined, and the results were compared with a control mix that made without addition of sodium gluconate. The hybrid alkaline paste and mortar mixes were prepared using a fixed proportion of OPC/fly ash (25%/75%), NaOH solution molarity of 9M, and sodium silicate to hydroxide ratio of 1.5. The results of this investigation found that the quick setting and abrupt loss of flowability of the control mix were improved by adding sodium gluconate, however, more promising results were observed at 7% and 10% sodium gluconate. The delay in polymerization due to lower availability of calcium ions, and adsorption of carboxyl and hydroxyl groups associated with sodium gluconate on the unreacted particles of binding materials and earlier formed products assisted in prolonging the time required for hardening. Further, the compressive strength declined at a higher dosage of sodium gluconate, however, the mortar mixes made with 2% and 4% sodium gluconate exhibited higher compressive strength than the control mix. The peak intensity of albite, nepheline, and C–S–H gel decreased at higher dosages of sodium gluconate, which was supported by a weaker microstructure characterized by more pores, micro-cracks, and partially reacted fly ash particles. Furthermore, the lower bridging oxygen content and greater Si–O–Na/ Si–O–T ratio at higher dosage of sodium gluconate confirms the delayed polymerization process.

A comparative study for organophosphate triesters and diesters in mice via oral gavage exposure: Tissue distribution, excreta elimination, metabolites and toxicity

Organophosphate triesters (tri-OPEs) and diesters (di-OPEs) may threaten human health through dietary intake, whereas little information is available about their fate in mammals. Herein, mice exposure experiments were carried out through gavage with six tri-OPEs and six di-OPEs, respectively. The residual levels of di-OPEs in mice were generally higher than those of tri-OPEs. The residual di-OPEs mainly distributed in the liver and blood while the most tri-OPEs remained in stomach, indicating easier transfer and lower metabolism levels of di-OPEs. The accumulation of tri- and di-OPEs with large octanol–water partition coefficients and long carbon chain were observed in tissues and feces, implying that the elimination of these OPEs through fecal excretion is an important elimination pathway. A total of 86 OPE metabolites were found in murine urine and feces, 57 of which were identified for the first time. For tri-OPEs, carboxylated OPEs had higher peak intensities and fewer interference factors among the metabolites, which could serve as ideal biomarkers. The predicted oral median lethal doses of OPEs and corresponding metabolites showed an increased toxicity of some hydroxylated OPEs and di-OPEs, needing further attention. These results provided new insights and evidence on the fates and biomarkers of OPEs exposure for mammals.

Surface engineering of Fe3O4@SiO2 Core–Shell nanoparticles: Role of CTAB/TEOS ratio

Core– shell Fe3O4@SiO2 nanoparticles with tunable SiO2 shell thickness and porosity were successfully synthesized using cetyltrimethylammonium bromide (CTAB) as the crosslinking agent and tetraethyl orthosilicate (TEOS) as the silica precursor. The increase in the O-H stretching peak intensity observed in the Fe3O4/CTAB and Fe3O4/CTAB/SiO2 nanoparticles was attributable to the increased number of hydroxyl groups resulting from hydrogen bonding between the head of CTAB and water molecules and the increased exposure of the SiO2 surface owing to CTAB dissolution. The shell thickness and porosity of the nanoparticles were controlled by adjusting the TEOS/CTAB ratio. Increasing the CTAB content while maintaining a fixed amount of TEOS resulted in a constant shell thickness but increased porosity. Conversely, increasing the TEOS content while fixing the amount of CTAB led to the formation of a double-shell structure with a new dense silica layer on top of the existing shell at concentrations exceeding a certain threshold. These findings provide valuable insights into the design and application of SiO2-coated nanoparticles tailored for various applications.