In this study, a catalyst derived from iron slag (Fe-S) was used for heterogeneous Fenton oxidation (H2O2/Fe-S) of paracetamol in aqueous solution; the conventional homogeneous Fenton reaction ...(H2O2/Fe2＋) was run in parallel for comparison. Degradation of paracetamol, in terms of chemical oxygen demand (COD) removal, was found strongly dependent on the solution pH, with the maximum efficiency obtained at pH 3 for both H2O2/Fe-S and H2O2/Fe2＋ systems. The efficacy of paracetamol degradation was also affected by the ratio (w/w) of hydrogen peroxide to iron, as the maxima degradation was observed at ratios of 1:2 and 2:1 for the heterogeneous and homogeneous Fenton, respectively. In addition, the degradation efficiency decreased when the initial paracetamol concentration increased from 100 mg/L to 500 mg/L. Kinetic experiments showed that degradation of paracetamol fitted a pseudo-first-order kinetic model well, as evidenced by the Kd values of the pseudo-first-order kinetic model that followed the same sequence as the degradation efficiency of paracetamol. Processes involved in the degradation of paracetamol by H2O2/Fe-S mainly included adsorption and oxidation; for latter, the presence of FeO, ZnO, and SiO2 in Fe-S constituent might enhance the decomposition of H2O2 and generate more *OH radicals. The *OH radical-mediated oxidation was confirmed by significant declines in the elimination of paracetamol when the system was subject to various radical-scavengers including t-butanol, chloride, and carbonate species.
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•Fe2＋ and Fe-S were used as catalysts for homogeneous and heterogeneous Fenton.•The paracetamol degradation by H2O2/Fe2＋ and H2O2/Fe-S reached the highest at pH 3.•The Fe2＋ ions released from Fe-S enhanced the formation of *OH radicals.•The paracetamol degradation followed pseudo-first order kinetic model.•The paracetamol degradation mechanism in H2O2/Fe-S system involved both adsorption and oxidation.
Critically ill patients are characterized by substantial pathophysiological changes that alter the pharmacokinetics (PK) of hydrophilic antibiotics, including carbapenems. Meropenem is a key ...antibiotic for multidrug-resistant Gram-negative bacilli, and such pathophysiological alterations can worsen treatment outcomes. This study aimed to determine the population PK of meropenem and to propose optimized dosing regimens for the treatment of multidrug-resistant Klebsiella pneumoniae in critically ill patients. Two plasma samples were collected from eligible patients over a dosing interval. Nonparametric population PK modeling was performed using Pmetrics. Monte Carlo simulations were applied to different dosing regimens to determine the probability of target attainment and the cumulative fraction of response, taking into account the local MIC distribution for K. pneumoniae. The targets of 40% and 100% for the fraction of time that free drug concentrations remained above the MIC (ƒT>MIC) were tested, as suggested for critically ill patients. A one-compartment PK model using data from 27 patients showed high interindividual variability. Significant PK covariates were the 8-h creatinine clearance for meropenem and the presence of an indwelling catheter for pleural, abdominal, or cerebrospinal fluid drainage for the meropenem volume of distribution. The target 100% ƒT>MIC for K. pneumoniae, with a MIC of ≤2 mg/liter, could be attained by the use of a continuous infusion of 2.0 g/day. Meropenem therapy in critically ill patients could be optimized for K. pneumoniae isolates with an MIC of ≤2 mg/liter by using a continuous infusion in settings with more than 50% isolates have a MIC of ≥32mg/L.
It is well-known that Ag-Au bimetallic nanoplates have attracted significant research interest due to their unique plasmonic properties and surface-enhanced Raman scattering (SERS). In recent years, ...there have been many studies on the fabrication of bimetallic nanostructures. However, controlling the shape, size, and structure of bimetallic nanostructures still has many challenges. In this work, we present the results of the synthesis of silver nanoplates (Ag NPls), and Ag-Au bimetallic core/shell and alloy nanostructures, using seed-mediated growth under green LED excitation and a gold salt (HAuCl
4
) as a precursor of gold. The results show that the optical properties and crystal structure strongly depend on the amount of added gold salt. Interestingly, when the amount of gold(
x
) in the sample was less than 0.6 μmol (
x
< 0.6 μmol), the structural nature of Ag-Au was core/shell, in contrast
x
> 0.6 μmol gave the alloy structure. The morphology of the obtained nanostructures was investigated using the field emission scanning electron microscopy (FESEM) technique. The UV-Vis extinction spectra of Ag-Au nanostructures showed localized surface plasmon resonance (LSPR) bands in the spectral range of 402-627 nm which changed from two peaks to one peak as the amount of gold increased. Ag-Au core/shell and alloy nanostructures were utilized as surface enhanced Raman scattering (SERS) substrates to detect methylene blue (MB) (10
−7
M concentration). Our experimental observations indicated that the highest enhancement factor (EF) of about 1.2 × 10
7
was obtained with Ag-Au alloy. Our detailed investigations revealed that the Ag-Au alloy exhibited significant EF compared to pure metal Ag and Ag-Au core/shell nanostructures. Moreover, the analysis of the data revealed a linear dependence between the logarithm of concentration (log
C
) and the logarithm of SERS signal intensity (log
I
) in the range of 10
−7
-10
−4
M with a correlation coefficient (
R
2
) of 0.994. This research helps us understand better the SERS mechanism and the application of Raman spectroscopy on a bimetallic surface.
It is well-known that Ag-Au bimetallic nanoplates have attracted significant research interest due to their unique plasmonic properties and surface-enhanced Raman scattering (SERS).
The movement of individual molecules inside living cells has recently been resolved by single particles tracking (SPT) method which is a powerful tool for probing the organization and dynamics of the ...plasma membrane constituents. Effective treatment of metastatic cancers requires the toxic chemotherapy, however this therapy leads to the multidrug resistance phenomenon of the cancer cells, in which the cancer cells resist simultaneously to different drugs with different targets and chemical structures. P-glycoprotein molecules which are responsible for multidrug resistance of many cancer cells have been studied by cancer biologists during past haft of century. Recently, advances in laser and detector technologies have enabled single fluorophores to be visualized in aqueous solution. The development of the total internal reflection fluorescent microscope (TIRFM) provided means to monitor dynamic molecular localization in living cells. In this paper, P-glycoproteins (PGP) were labeled with green fluorescent protein (GFP) in living cell membrane of Madin-Darby canine kidney (MDCK) and the TIRFM method was used to characterize the dynamics of individual protein molecules on the surface of living cells. An evanescent field was produced by a totally internally reflected and a laser beam was illuminated the glass-water interface. GFP-PGP proteins that entered the evanescent field appeared as individual spots of light which were slighter than background fluorescence. We obtained high-resolution images and diffusion maps of membrane proteins on cell surface and showed the local diffusion properties of specific proteins on single cells. We also determined the diffusion coefficient, the mean square displacement and the average velocity of the tracked particles, as well as the heterogeneity of the cell environment. This study enabled us to understand single-molecule features in living cell and measure the diffusion kinetics of membrane-bound molecules.
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•The dynamic of P-glycoprotein (Pgp) in living cell membrane of Madin-Darby canine kidney (MDCK) was studied by SMT method.•Pgp molecules labeled with the green fluorescent protein were tracked using the TIRFM.•The diffusion coefficient as well as the heterogeneity of the cell environment were determined.•The mobility of individual molecules was analyzed based on the probability distribution of displacement and trajectories of Pgp molecules.•Intracellular Pgp molecules existed in two types, single and aggregate.
Bone metabolism is regulated by endocrine systems, so people exposed to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may suffer adverse effects on bones and teeth. We reviewed ...previous publications in which effects of PCDD/Fs and dioxin-like polychlorinated biphenyls on the teeth and bones of animals and humans were found. The aim was to identify future research directions, particularly for epidemiological studies of populations exposed to PCDD/Fs in the environment. Exposure of fetuses to PCDD/Fs may affect odontogenesis, particularly enamel formation, but the effects of PCDD/Fs on bone genesis are limited to palatine bone. Exposure to PCDD/Fs in milk may affect both teeth and bones, but the effects on bones may be reversible. Exposure to high PCDD/F concentrations even during adulthood may adversely affect teeth. Exposure to PCDD/Fs may induce osteogenesis and improve bone properties because the disrupting effects of PCDD/Fs cause bone remodeling and vitamin D activation. More studies involving humans are required to investigate previously found associations between the PCDD/F concentrations humans are exposed to and biological markers for teeth and bones, including metabolites of vitamin D.
Fifty-five children aged 2 years from a birth cohort in the largest dioxin-contaminated area in Bien Hoa city, Vietnam participated in this survey to examine gaze behavior. Exposure levels were ...indicated by 2,3,7,8-tetrachlorodibenzo-p-dibenzodioxin (TCDD) and toxic equivalent of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran (TEQ-PCDD/Fs) levels in maternal breast milk. The percentage of the total fixation duration on the face (% Face), mouth (% Mouth), and eye areas (% Eyes) when viewing silent and conversation scenes was used as gaze behavior indices. When they reached 3-year-old, autistic behavior was assessed using the Autism Spectrum Rating Scale (ASRS). A general linear model adjusted for confounding factors was used to compare gaze indices and ASRS scores between high and low dioxin exposure groups. Effects of perinatal dioxin exposure on gaze behavior were found only when viewing conversation scenes indicated by lower % Face for boys in high TCDD exposure group and lower % Eyes for girls in high TEQ-PCDD/Fs group. Increased autistic traits showed by higher ASRS scores at 3-year-old were found in both gender in the high TCDD exposure group. These findings indicate that perinatal TCDD and TEQ-PCDD/Fs exposure may reduce gaze behavior in 2-year-old children, predicting increased autistic traits at 3-year-old.
We herein present a simple, fast, efficient and environmentally friendly method for preparing silver nanoparticles (AgNPs) using the solution plasma method in the presence of extracts from
Paramignya ...trimera
(
P. trimera
). The effects of
P. trimera
extract concentrations and the applied voltage on the formation of AgNPs were investigated. Surface plasmon resonance spectra show a strong peak at 413 nm for the prepared samples. The Fourier-transform infrared spectroscopy measurement results indicated the presence of possible functional groups in the prepared AgNPs. Morphological analysis revealed that the AgNPs were spherical with an average size of 8 nm. The prepared AgNPs exhibited good stability in solution compared to that of AgNPs prepared by the solution plasma technique without
P. trimera
extract. The formation mechanism of AgNPs is also proposed. The prepared AgNPs exhibited high antibacterial ability against Gram (+)
Staphylococcus aureus
, Gram ()
Pseudomonas aeruginosa
bacteria and strong anticancer activity for the AGS gastric cancer cell line. The obtained results demonstrated that this is a simple, rapid, environmentally friendly method for preparing AgNPs instead of conventional methods using chemical reducing agents for potential applications.
A green, facile and fast approach based on the solution plasma technique was utilized for synthesizing AgNPs for antibacterial and anticancer applications.
Bien Hoa airbase is the most dioxin-polluted hotspot in Vietnam. In 2012, a birth cohort living around Bien Hoa airbase was recruited for assessment of physical and neurological development. In the ...present study, neurodevelopment scores at 5 years of age were assessed by the Kaufman Assessment Battery for Children, Second Edition and the Movement Assessment Battery for Children, Second Edition for 185 children in Bien Hoa and 104 children in Ha Dong (unexposed control group) to clarify the effects of dioxin. 2,3,7,8-tetrachlorodibenzo-p-dioxin concentrations in breast milk of women in Bien Hoa were approximately three times higher than those of women in Ha Dong (2.33 vs. 0.69 pg/g fat, p < 0.001). In general, neurodevelopment scores were lower in Bien Hoa children than in Ha Dong children. In boys, scores differed for number recall (12.6 vs. 14.0, p = 0.036), triangles (10.7 vs. 12.4, p = 0.005), manual dexterity (8.3 vs. 9.7, p = 0.037), balance (7.4 vs. 10.3, p < 0.001), and total movement scores (8.0 vs. 10.1, p = 0.003). After adjusting for covariates, linear regression analysis indicated that the scores of the triangles, balance, and total movement tests were inversely associated with levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin and of toxic equivalency of polychlorinated dibenzodioxins and polychlorinated dibenzofurans. In girls, scores differed for the triangles test (11.0 vs. 12.6, p = 0.005), hand movement test (9.6 vs. 11.3, p = 0.003), and balance test (9.1 vs. 10.7, p = 0.050); toxic equivalency of polychlorinated dibenzofurans was inversely associated with hand movement and balance scores. Overall, perinatal dioxin exposure appears to have a long-term impact on neurodevelopment.
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•Dioxin levels in breast milk were three times higher in the sprayed area.•Child cognitive and motor scores were significantly lower in the sprayed area.•Cognitive and motor scores were inversely associated with dioxin exposure.•Perinatal dioxin exposure has a long-term impact on child neurodevelopment.
Here bismuth (Bi) was utilized to substitute Te sites to increase the hole concentration, thereby enhancing the thermoelectric performance of GaTe. Bi-doped GaTe single crystals have successfully ...been fabricated by a temperature gradient technique. Bi atoms acting as acceptors helped to increase hole concentration from 9.43 × 1015 cm-3 for pristine GaTe to 0.63, 0.90, 1.20, and 1.63 × 1017 cm-3 for BGT-1, BGT-2, BGT-3, and BGT-4 single crystals, respectively. Moreover, the carrier mobility was increased up to 68.25 cm2 V-1 s-1 due to the crystallinity improvement of GaTe. Consequently, the electrical conductivity and power factor (PF) reached the respective maximum values of 3.62 S cm-1 and 1.21 μW cm-1 K-2 at 500 K for BGT-4 crystals. Meanwhile, Bi doping less affected the thermal transport properties of GaTe single crystals. A peak zT of ~0.02 was achieved at 700 K for the BGT-4 sample.
Bi atoms not only substituted Te sites, generating free holes but also acted as a chemical agent, thereby increasing simultaneously carrier concentration and carrier mobility of GaTe single crystals. Consequently, a peak zT of 0.02 was achieved at 700 K for the sample with the room-temperature hole concentration of 1.6 x 1017 cm-3 (BGT-4 sample). Display omitted
•We successfully fabricated Bi-doped GaTe single crystals by a temperature gradient technique.•Bi atoms occupying Te sites act as acceptors, leading to increase hole concentration.•Bi doping increases mobility of free holes in GaTe single crystals.•Bi doping less affects the thermal transport properties of GaTe single crystals.•A peak zT of 0.02 was reached at 700 K for the BGT-4 sample.
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