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A needle trap device (NTD) was developed using an amide-based covalent-organic framework (COF), chemically bonded to silica nanoparticles. The NTD was coupled with gas chromatography-flame ionization detection (GC-FID) and employed for the headspace microextraction analysis of halogenated hydrocarbons (HHCs) in the air. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM) techniques. Optimal values for the experimental variables were assessed using response surface methodology (RSM) with a central composite design (CCD), thereby reducing the number of experiments, material consumption, costs, and time. The optimal values for desorption time and temperature were obtained 5 min and 260 °C, respectively. Breakthrough volume (BtV) was studied over the range of 0.5 - 3 times the occupational exposure limit (OEL) and its optimal value was found to be 1200 mL. The optimal sampling temperature and relative humidity (RH) were obtained 20 °C, and 15 %, respectively. The limits of detection (LODs) and limits of quantification (LOQs) were ranged from 0.013 to 0.077 μg l -1 and 0.041 to 0.21 μg l -1 , respectively, with a linear dynamic range (LDR) of 0.04 to 100 μg l -1 . The method's repeatability and reproducibility (RSD %) were observed over the ranges of 5.3 - 6.4 % and 4.7 -6.9 %, respectively. A statistically validated agreement was observed between the NTD-GC-FID method and the NIOSH 1003 standard procedure for the sampling and determination of HHCs in real workplace air samples, demonstrating the reliability and accuracy of the developed approach., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: This study aimed to develop a deep convolutional neural network (CNN) for automatic classification of pubertal growth spurts using cervical vertebral maturation (CVM) staging based on the lateral cephalograms of an Iranian subpopulation., Material and Methods: Cephalometric radiographs were collected from 1846 eligible patients (aged 5-18 years) referred to the orthodontic department of Hamadan University of Medical Sciences. These images were labeled by two experienced orthodontists. Two scenarios, including two- and three-class (pubertal growth spurts using CVM), were considered as the output for the classification task. The cropped image of the second to fourth cervical vertebrae was used as input to the network. After the preprocessing, the augmentation step, and hyperparameter tuning, the networks were trained with initial random weighting and transfer learning. Finally, the best architecture among the different architectures was determined based on the accuracy and F-score criteria., Results: The CNN based on the ConvNeXtBase-296 architecture had the highest accuracy for automatically assessing pubertal growth spurts based on CVM staging in both three-class (82% accuracy) and two-class (93% accuracy) scenarios. Given the limited amount of data available for training the target networks for most of the architectures in use, transfer learning improves predictive performance., Conclusions: The results of this study confirm the potential of CNNs as an auxiliary diagnostic tool for intelligent assessment of skeletal maturation staging with high accuracy even with a relatively small number of images. Considering the development of orthodontic science toward digitalization, the development of such intelligent decision systems is proposed., (Copyright © 2023 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

A Z-scheme Bi 2 WO 6 /CNT/TiO 2 photocatalyst was synthesized hydrothermally and loaded on chitosan nanofibers with different mass percentages using the electrospinning process. The batch adsorption experiments for chitosan nanofibrous samples containing Bi 2 WO 6 /CNT/TiO 2 revealed that the adsorption process and its kinetic followed the Langmuir isotherm and pseudo-second-order model, respectively. A planar microreactor with a reusable plate-type configuration was fabricated employing an inexpensive micromachining technique and integrated with chitosan/Bi 2 WO 6 /CNT/TiO 2 nanofibers. The synergistic effect of the adsorption and photocatalysis was assessed for removing cephalexin under simulated sunlight irradiation in a continuous flow microreactor. The nanofibers containing 15 wt% of Bi 2 WO 6 /CNT/TiO 2 exhibited the most removal efficiency. The effects of operational variables were investigated in the microreactor and optimized using response surface methodology as light intensity = 17.45 W/m 2 , retention time = 256 s, pH = 4.8, and initial cephalexin concentration = 29 mg/L. At this condition, cephalexin and TOC removal efficiencies reached 99.2% and 92.4%, respectively. The kinetic of disappearance of cephalexin under optimal conditions followed the Langmuir-Hinshelwood model. The adsorption equilibrium constant deduced from this model was similar to that one calculated from the Langmuir isotherm model. At the optimum condition, cephalexin removal efficiency reduced to 80% after 1500 min of microreactor operation and the nanofibers revealed appropriate stability and reusability., (Copyright © 2022 Elsevier B.V. All rights reserved.)

A relatively new adsorbent based on covalent organic frameworks (COFs) was employed for the first time to extract and determine Trans, trans-muconic acid (tt-MA), Mandelic acid (MA), Hippuric acid (HA), and 3-Methylhippuric acid (m-MHA) in urine. For this purpose, microextraction was performed using the packed sorbent (MEPS) method. Following the extraction process, the prepared samples were specified via the high-performance liquid chromatography-ultraviolet detector system. The precipitation polymerization was applied to synthesize the Fe 3 O 4 @TbBd nanobeads, and the morphological and dimensional structures of the products were specified with FE-SEM images. Some key variables affecting the extraction efficiency (i.e., sample volume, elution volume, condition and washing solvents, type and volume of elution solvent, extraction cycles, temperature, and pH of the sample solution) were investigated. In ideal conditions, the limit of detection (LOD) was obtained from 0.02 µg/ml for tt-MA to 0.5 µg/ml for MA. Calibration curves (at five-point) were plotted in the range 0.05-5 µg/ml for tt-MA to 1-300 µg/ml for MA (R 2  > 0.98). Moreover, intra- and inter-day precision values were 3.1-5.5 and 4.6-9.8%, respectively. The developed method was successfully employed to determine four analytes in three concentrations (low, medium, and high QCs). The results showed a satisfactory recovery (70-87%). COF-MEPS technique is a rapid, easy, user-friendly, and environment-friendly method for separating the minimum values of all BTEXs chief biomarkers from urine samples without using complicated processes and only with one adsorbent. Also, it can be a good alternative for biomonitoring the workers exposed to BTEX compounds in occupational and environmental access., (Copyright © 2022 Elsevier B.V. All rights reserved.)

In order to overcome the poor adhesion of zirconia-silica coating electrophoretically deposited on 316 L stainless steel, graphene oxide (GO) was used as an interlayer. The effect of this interlayer on morphological, microstructural, corrosion performance and bioactivity behavior of ZrO 2 -10 at. % SiO 2 coating was studied. The zirconia-silica coating with the GO interlayer revealed a higher barrier performance as a more compact and a greater adhesive layer to the substrate was created. Indeed, the GO interlayer led to an improvement in apatite formation on zirconia-silica coating surface probably due to create higher roughness. Briefly, the GO interlayer was effective on enhancement of electrochemical performance and biological property of zirconia-silica composite coating, making it a suitable candidate for biomaterials applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The purpose of this study was to develop a new method for the sampling and analysis of naphthalene (Nap) and phenanthrene (Phe) in air. XAD-2 sorbent was prepared with polyaniline (PANI) to increase its adsorption area. Thus, 22-gauge needles were packed with XAD-2/PANI sorbent for the extraction of Nap and Phe, and sampling of the analytes of interest. The compounds were dynamically sampled from the headspace of the flask in laboratory and then analyzed using a gas chromatography (GC) device equipped with flame ionization detector (FID). The needle trap device (NTD) with the proposed sorbent was more sensitive and accurate than the NIOSH 5515 method. The results showed that the optimal temperature and time for the desorption of the analytes were 350 °C and 8 min, respectively. The analytical parameters such as carryover effect, breakthrough volume, and storage time were examined. The repeatability of the method was determined to be 9.4-13.5% for Nap and 7.1-15.7% for Phe. The limits of detection (LOD) for the analytes were in the range 0.002 - 0.09 ng L -1 , and the limits of quantitation (LOQ) were in the range 0.01- 0.23 ng L -1 . It was also found that the NTD packed with XAD-2/PANI sorbent was a sensitive and cost-effective method, and offered a high accuracy for the sampling and analysis of PAHs in air., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this study, two hybrid metal organic frameworks including MOF-5@ Fe 3 O 4 -NH 2 and MOF-5@ SBA-15 for the first time were synthetized and combined with microextraction by packed sorbent (MEPS) to extract of mandelic acid (MA) from urine samples. The synthetized sorbents were characterized using FE-SEM, XRD and FT-IR techniques. The important parameters in MEPS procedure including sample volume, extraction draw&#95;discard cycles, elution solvent volume and desorption draw-eject cycles were optimized using response surface methodology (RSM) with central composite design (CCD). The results indicated that the volume of elution solvent was the most important parameter in the recovery of MA by MOF-MEPS procedure. The optimized MOF-MEPS method offered an acceptable efficiency for the recovery of MA from urine samples (MOF-5@Fe 3 O 4 -NH 2 and MOF-5@SBA-15: 94.5% and 90.3%, respectively, RSD < 3.54%). The limit of detection (LOD) of MA calculated by MOF-MEPS procedure combined with high performance liquid chromatography for MOF-5@ Fe 3 O 4 -NH 2 and MOF-5@ SBA-15 were calculated to be 0.10 and 0.13 μg mL -1 , respectively. The linearity dynamic ranges (LDRs) determination of urinary MA by MOF-5@ Fe 3 O 4 -NH 2 and MOF-5@ SBA-15 were 0.2-100 and 0.2-90 μg mL -1 , respectively. The results of the present study implied that the proposed technique is a fast and sensitive procedure for extraction and determination of MA from urine samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Carbotrap B as a highly pure surface sorbent with excellent adsorption/desorption properties was packed into a stainless steel needle to develop a new needle trap device (NTD). The performance of the prepared NTD was investigated for sampling, pre-concentration and injection of benzene, toluene, ethyl benzene, o-xylene, and p-xylene (BTEX) into the column of gas chromatography-mass spectrometry (GC-MS) device. Response surface methodology (RSM) with central composite design (CCD) was also employed in two separate consecutive steps to optimize the sampling and device parameters. First, the sampling parameters such as sampling temperature and relative humidity were optimized. Afterwards, the RSM was used for optimizing the desorption parameters including desorption temperature and time. The results indicated that the peak area responses of the analytes of interest decreased with increasing sampling temperature and relative humidity. The optimum values of desorption temperature were in the range 265-273°C, and desorption time were in the range 3.4-3.8min. The limits of detection (LODs) and limits of quantitation (LOQs) of the studied analytes were found over the range of 0.03-0.04ng/mL, and 0.1-0.13ng/mL, respectively. These results demonstrated that the NTD packed with Carbotrap B offers a high sensitive procedure for sampling and analysis of BTEX in concentration range of 0.03-25ng/mL in air., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: The rough surface of Hawley removable appliances provides an environment for plaque accumulation, leading to enamel demineralization. The aim of this study was to evaluate the effect of silver nanoparticles incorporated into acrylic baseplates of orthodontic retainers on Streptococcus mutans colony-forming units., Methods: Sixty-six orthodontic patients at the debonding stage were randomly assigned to 2 sex-matched groups with stratified block randomization: group 1 received conventional removable retainers; group 2 received removable retainers containing silver nanoparticles (about 40 nm in size and 500 ppm in concentration). After comprehensive orthodontic treatment, patients who revealed no clinical evidence of dental caries, periodontal pockets, or systemic disease were considered eligible for this study. Swab samples were taken from the maxillary palatal side from the patient in the dental chair at retainer placement (T1, 1 week after debonding the fixed orthodontic appliance) and T2, 7 weeks later. The main outcome was to compare the number of S mutans colony-forming units between the 2 groups 7 weeks after retainer delivery. The results were analyzed by using analysis of covariance. The participants and the assessors were blinded to the allocation groups., Results: Twenty-nine patients in the control group and 32 in the intervention group were analyzed. At T1, the intervention group had higher S mutans colony counts relative to the control group. The analysis of covariance test showed a significant reduction of colonies in the intervention group after 7 weeks. The mean difference of colony counts between the 2 groups was 40.31 (95% confidence interval, 24.83-55.79; P < 0.001)., Conclusions: Adding silver nanoparticles to the acrylic plate of retainers had a strong antimicrobial effect against S mutans under clinical conditions., Registration: This study was registered as a clinical trial at the Iranian Clinical Trial Center under the code number IRCT201309239086N2., Funding: This trial was supported by Hamadan Dental Research Centre, Hamadan University of Medical Sciences, Hamadan, Iran., (Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)