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1.
Radiother Oncol ; 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33831446

RESUMO

BACKGROUND AND PURPOSE: Delineation of organs at risk (OARs), such as the bladder, rectum and sigmoid, plays an important role in the delivery of optimal absorbed dose to the target owing to the steep gradient in high-dose rate brachytherapy (HDR-BT). In this work, we propose a deep convolutional neural network-based approach for fast and reproducible auto-contouring of OARs in HDR-BT. MATERIALS AND METHODS: Images of 113 patients with locally-advanced cervical cancer were utilized in this study. We used ResU-Net deep convolutional neural network architecture, which uses long and short skip connections to improve the feature extraction procedure and the accuracy of segmentation. Seventy-three patients chosen randomly were used for training, 10 patients for validation, and 30 patients for testing. Well established quantitative metrics, such as Dice similarity coefficient (DSC), Hausdorff distance (HD), and average symmetric surface distance (ASSD), were used for evaluation. RESULTS: The DSC values for the test dataset were 95.7± 3.7%, 96.6±1.5% and 92.2 ± 3.3% for the bladder, rectum, and sigmoid, respectively. The HD values (mm) were 4.05±5.17, 1.96±2.19 and 3.15±2.03 for the bladder, rectum, and sigmoid, respectively. The ASSDs were 1.04±0.97, 0.45±0.09 and 0.79±0.25 for the bladder, rectum, and sigmoid, respectively. CONCLUSION: The proposed deep convolutional neural network model achieved a good agreement between the predicted and manually defined contours of OARs, thus improving the reproducibility of contouring in brachytherapy workflow.

2.
Anal Chem ; 93(13): 5394-5402, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33724794

RESUMO

Bioinspired solid-state nanopores and nanochannels have attracted interest in the last two decades, as they are envisioned to advance future sensing, energy conversion, and separation concepts. Although much effort has been made regarding functionalization of these materials, multifunctionality and accurate positioning of functionalities with nanoscale precision still remain challenging. However, this precision is necessary to meet transport performance and complexity of natural pores in living systems, which are often based on nonequilibrium states and compartmentalization. In this work, a nanolocal functionalization and simultaneous localized sensing strategy inside a filtering mesoporous film using precisely placed plasmonic metal nanoparticles inside mesoporous films with pore accessibility control is demonstrated. A single layer of gold nanoparticles is incorporated into mesoporous thin films with precise spatial control along the nanoscale layer thickness. The local surface plasmon resonance is applied to induce a photopolymerization leading to a nanoscopic polymer shell around the particles and thus nanolocal polymer placement inside the mesoporous material. As near-field modes are sensitive to the dielectric properties of their surrounding, the in situ sensing capability is demonstrated using UV-vis spectroscopy. It is demonstrated that the sensing sensitivity only slightly decreases upon functionalization. The presented nanolocal placement of responsive functional polymers into nanopores offers a simultaneous filtering and nanoscopic readout function. Such a nanoscale local control is envisioned to have a strong impact onto the development of new transport and sensor concepts, especially as the system can be developed into higher complexity using different metal nanoparticles and additional design of mesoporous film filtering properties.

3.
Langmuir ; 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397113

RESUMO

The addition of surfactants to pure water for specific applications has made controlling the impact dynamics of surfactant-laden droplets a complex phenomenon. This work investigates the influence of the molecular weight (MW), concentration, and ionic nature of the surfactants as well as the substrate surface characteristics on the impact dynamics of surfactant-laden droplets using a high-speed camera at 10 000 frames per second. Sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, and n-decanoyl-n-methylglucamine were used as anionic, cationic, and nonionic surfactants, respectively. We used hydrophilic glass slides, hydrophobic polytetrafluoroethylene, and superhydrophobic alkyl ketene dimer (AKD) as substrates. The results show that the efficiency of the surfactant addition in increasing the maximum spreading diameter is significantly influenced by the molecular weight and ionic nature of the solutions as well as the nonwettability of the substrate. Among all of the surfaces examined, the concentration and ionic nature of the solutions were found to be more dominant parameters in determining the energy dissipation in the retraction phase of the droplet impact on the superhydrophobic AKD surfaces. As the concentration decreases or positive charges are present in the solution, it is more likely to observe a similar retraction dynamic to pure water when the droplet hits the superhydrophobic AKD having negatively charged surface sites. Finally, in terms of the impact outcomes of the surfactant-laden droplets on the superhydrophobic AKD, it is shown that the influence of the surfactant addition is more noticeable at lower Weber numbers, where the droplet tries to rebound by overcoming the energy loss that occurred in the spreading.

4.
Sci Rep ; 11(1): 173, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420272

RESUMO

The conventional reproduction methods are not efficient for regeneration of Sumac (Rhus coriaria L.). The purpose of this work was to study the micropropagation of R. coriaria using lateral buds as explant in Murashige and Skoog (MS) medium with different concentrations of plant growth regulator (PGRs). Four concentrations of Benzylaminopurine (BAP) in combination with three concentrations of indol-3-butyric acid (IBA) and 1.0 mg/L gibberellic acid (GA3) were tested for establishment and shoot multiplication. For root induction, IBA was used at four levels combined with 0, 0.5 and 1 mg/L of naphthalene acetic acid (NAA) in full and half strength of MS medium. BAP at 2 mg/L with 1 mg/L IBA was best, with 88.88% of establishment. The highest shoot proliferation (12.30 ± 0.30) was obtained in medium fortified with 2 mg/L BAP plus 0.5 mg/L IBA and the highest shoot length (8.50 cm) was obtained at 3 mg/L BAP plus 1 mg/L IBA. The highest rooting (100%) was observed in 1/2-strength MS medium containing 1 mg/L IBA with 0.5 mg/L NAA. In conclusion, an efficient protocol with high rate of proliferation and rooting is described for R. coriaria, which can be used in massive propagation.

5.
Carbohydr Polym ; 256: 117554, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483057

RESUMO

In recent years, many studies have been conducted on the production of edible films from emerging gums, which are mostly made from botanical sources. However, each one interacts differently with the film compounds, producing films with different properties that may improve or hinder their utilization in food packaging. Therefore, the aim of this review was to investigate and compare the physical, mechanical, thermal and structural properties of edible films produced with these emerging gums. The results of this review showed that it is possible to produce edible films with desirable physical, mechanical and thermal properties by optimizing the amounts and type of compounds in film formulations such as plasticizers, nanoparticles, lipid compounds, crosslinkers and combination of gums with other biopolymers. The future trends of this research include the deepening of knowledge to understand the molecular structures of emerging gums and to address the shortcomings of films based on these gums for their industrial-scale application in food packaging.

6.
Sci Rep ; 10(1): 21261, 2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33277523

RESUMO

This paper reports on the design, development, and test of a multi-channel wireless micro-electrocorticography (µECoG) system. The system consists of a semi-implantable, ultra-compact recording unit and an external unit, interfaced through a 2.4 GHz radio frequency data telemetry link with 2 Mbps (partially used) data transfer rate. Encased in a 3D-printed 2.9 cm × 2.9 cm × 2.5 cm cubic package, the semi-implantable recording unit consists of a microelectrode array, a vertically-stacked PCB platform containing off-the-shelf components, and commercially-available small-size 3.7-V, 50 mAh lithium-ion batteries. Two versions of microelectrode array were developed for the recording unit: a rigid 4 × 2 microelectrode array, and a flexible 12 × 6 microelectrode array, 36 of which routed to bonding pads for actual recording. The external unit comprises a transceiver board, a data acquisition board, and a host computer, on which reconstruction of the received signals is performed. After development, assembly, and integration, the system was tested and validated in vivo on anesthetized rats. The system successfully recorded both spontaneous and evoked activities from the brain of the subject.

7.
Int J Pharm ; 593: 120103, 2020 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-33242586

RESUMO

Quantifying drug delivery to the site of action using locally-acting nasal suspension sprays is a challenging but important step toward understanding bioequivalence (BE) between test and reference products. The main objective of this study was to investigate the in vitro deposition pattern of two common but different locally-acting nasal suspension sprays using multiple nasal cavities. Twenty anatomically accurate nasal replicas were developed from high-resolution sinonasal computed tomography scans of adults with healthy nasal airways. The airways were segmented into two regions of anterior and posterior to the internal nasal valve. Both sides of the septum were considered separately; hence, 40 nasal cavities were studied. The positioning of the spray nozzle in all 40 cavities was characterized by the head angle, coronal angle, and the insertion depth. Despite using a controlled protocol to minimize the anterior losses, a wide range of variability in posterior drug delivery was observed. The observed intersubject variability using this in vitro method may have important implications for understanding BE of locally-acting nasal suspension sprays.

8.
Hemoglobin ; : 1-5, 2020 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-33164584

RESUMO

Hydroxyurea (HU) activates the γ-globin gene, resulting in increased Hb F synthesis. The SOX6 gene is a member of the Sox (Sry-type HMG box) family of transcription factors, characterized by minor groove binding domain. The DNA binding domain of this gene is encoded by exon 14. We assessed the relationship between response to HU and exon 14 of the SOX6 gene sequence variations in patients with non transfusion-dependent thalassemia (NTDT). One hundred NTDT patients from southern Iran underwent HU therapy randomly participated in this cross-sectional study between February 2013 and October 2014. Based on response to HU therapy, the patients were divided into two groups: good and poor responder. Sequence variations of exon 14 of the SOX6 gene was assayed by the Sanger sequencing technique. From all evaluated single nucleotide polymorphisms (SNPs) as above, we found no significant association between sequence variations of exon 14 of the SOX6 gene and response to HU therapy (p > 0.05). It seems that no SNPs in exon 14 of the SOX6 gene is associated with response to HU in NTDT patients, but more studies are needed for further evaluation.

9.
Crit Rev Food Sci Nutr ; : 1-15, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33207940

RESUMO

Cold plasma is one of the techniques used in recent years to improve the functionality and interfacial attributes of biopolymers. Employing cold plasma for the treatment and modification of biopolymers possesses several advantages including its biocompatibility, elimination of toxic solvents usage, treatment consistency, and appropriateness for heat-sensitive ingredients. Most studies have presented the efficacious use of cold plasma treatment in improving structural, mechanical and thermal properties of film composites. In addition, cold plasma improves the film surface characteristics, particularly in protein-based films, through bringing up the polar functional groups onto the bio-composite surface, consequently increasing roughness, improving printability, increasing adhesion, and reducing contact angle; while it is not effective in the improvement of water vapor permeability of edible films. Cold plasma-treated edible packaging films experienced significant improvement where exposed to microbial contaminations, mainly due to the non-thermal nature of cold plasma technology leading to the protection of antimicrobial potency of bioactive compounds and antimicrobial constitutes. Therefore, it can be concluded that cold plasma treatment is an innovative strategy to strengthen the edible film characteristics as a promising alternative to the currently used chemical and physical modification approaches.

10.
Iran J Pathol ; 15(4): 261-267, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32944037

RESUMO

Background & Objective: Concentration of low-density lipoprotein (LDL) is a known risk factor for cardiovascular disease which is routinely measured or calculated as LDL-C in clinical laboratories. In order to decrease the cost, instead of its measuring, it is recommended to calculate it using multiple formulas that have been introduced up to now. The aim of this study was to assess the results of various formulas and comparison of these results with those of measuring method and to clarify the best formula for the Iranian population. Methods: Concentrations of total cholesterol (TC), triglyceride (TG), cholesterol of high-density lipoprotein (HDL-C) and LDL-C in serums of 471 overnight fasting individuals were measured and also LDL-Cs of these samples were calculated by eleven different formulas according to their TC, TG, and HDL-C concentrations. Subsequently, results of measured and calculated LDL-C were analyzed statistically by paired t-test, correlation coefficient, and Passing-Bablok regression. In addition, for clinical evaluation, the differences between calculated and measured mean results were calculated and compared with an allowable total error. Results: Paired t-test unraveled a significant difference between the results of measured and calculated LDL-C by various formulas. But for some formulas, these differences were not clinically significant. The best clinical and statistical agreement (correlation coefficient) was obtained by the Friedewald equation. Conclusion: By using validated methods which have correct calibration and control system for measuring TC, TG, and HDL-C, we can use the Friedewald formula for calculating LDL-C in serum samples with TG up to 400 mg/dL.

11.
Environ Sci Pollut Res Int ; 27(35): 44218-44229, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32761348

RESUMO

In the present work, biological hydroxyapatite (Bio-HAp) was generated from waste poultry bone and modified with magnesium oxide (MgO) nanoparticles (Bio-HAp/MgO) and used in the adsorption process of methyl violet (MV). The Bio-HAp and Bio-HAp/MgO mesoporous composites were characterized using physicochemical techniques. Bio-HAp and Bio-HAp/MgO composites had crystalline and mesoporous structures. The specific surface area of Bio-HAp/MgO mesoporous composites (14.7 m2/g) was higher and lower than that of Bio-HAp (4.6 m2/g) and MgO (154.9 m2/g), respectively. The effect of pH (2-10), temperature (25-45 °C), contact time (10-50 min), initial MV concentration (5-25 mg/L), and Bio-HAp/MgO quantity (0.5-2.5 g/L) on the adsorption efficiency was optimized through response surface methodology-central composite design (RSM-CCD). Among four isotherm models, the Freundlich isotherm (R2 > 0.98) was better matched with the equilibrium data. Based on the isotherm parameters (E, n, and RL), the MV adsorption process using Bio-HAp particles and Bio-HAp/MgO mesoporous composites is physical and desirable. The pseudo-second-order (R2 > 0.97) was more potent than the other models for modeling kinetic data. According to the thermodynamic investigation, the MV adsorption was an exothermic and spontaneous process. The mesoporous composite had good reusability to remove MV dye from liquid media up to 5 steps. Bio-HAp particles and Bio-HAp/MgO mesoporous composites were tested for treatment, which significantly reduced the dye content of the real sample.


Assuntos
Violeta Genciana , Poluentes Químicos da Água , Adsorção , Animais , Durapatita , Concentração de Íons de Hidrogênio , Cinética , Óxido de Magnésio , Aves Domésticas
13.
Environ Sci Pollut Res Int ; 27(28): 35792-35801, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32601873

RESUMO

The present study aimed to remove tetracycline (TET) antibiotic molecule from an aqueous medium using adsorbents prepared from Rhizopus oryzae biomass. The TET adsorption process was discontinuous and the adsorbent biomass was crude and NaOH-sonication-modified Rhizopus oryzae fungi. Specific active surface area for crude and modified Rhizopus oryzae was 10.38 m2/g and 20.32 m2/g, respectively. The results showed that the maximum TET adsorption efficiency was determined at pH 4, temperature 25 °C, initial TET concentration 10 mg/L, contact time 80 min, and biomass quantity 2 g/L. The equilibrium behavior showed that the Langmuir model suitably described the process. The maximum TET adsorption capacity was determined to be 38.02 mg/g and 67.93 mg/g, respectively, indicating that the method of biomass modification promoted the bio-adsorption capacity. A higher correlation coefficient (R2) and lower RMSE for the pseudo-first-order kinetic than other models showed its ability to describe the behavior of TET bio-adsorption. The enthalpy thermodynamic parameter (ΔH°) for the TET adsorption process was determined - 63.847 kJ/mol and - 85.226 kJ/mol for the raw and modified Rhizopus oryzae, respectively. Therefore, it can be suggested that the biomass of Rhizopus oryzae especially the modified version can be effectively used for the TET removal from aqueous environments.


Assuntos
Rhizopus , Poluentes Químicos da Água , Adsorção , Antibacterianos , Biomassa , Concentração de Íons de Hidrogênio , Cinética , Sonicação , Temperatura , Tetraciclinas , Termodinâmica
14.
Chin J Traumatol ; 23(5): 265-270, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32680704

RESUMO

PURPOSE: Various organizations and institutions are involved in road traffic injury (RTI) and crash registration such as police, forensic medicine organization, hospitals and emergency medical services. But there is a substantial uncertainty in interpreting the data, duplicated data collection and missing data in relation to RTI in most systems. This study aims to identify data sources for RTI surveillance in Iran and to explore traffic safety data source domains, data elements and detailed information by each data source. METHODS: This is a qualitative study which was conducted in 2017 in Iran. Data were collected employing semi-structured interviews with informants in road safety organizations in relation to traffic safety including Police, Ministry of Health and Medical Education as well as Forensic Medicine Organization and other authorities-in-charge. For completing the preliminary extraction information, the minimum data set was used and compared in each system. RESULTS: Eight different organizations relevant to road traffic safety were identified. The main domain of data provided by each one consists of Emergency Medical System form, Police KAM114 form, Ministry of Transport and Road Administration, Red Crescent Organization/Disaster Management Information System, Ministry of Health and Medical Education, Forensic Medicine Organization, Insurance Company and Ministry of Justice. Each system has its own database, based upon its scope and mainly at crash and post-crash status and little on pre-crash circumstance. CONCLUSION: All current registry systems are not surveillance systems for RTI prevention. Huge data have been collected in various registry systems in Iran, but most of the collected variables are duplicated in each system. On the other hand, some variables like alcohol and substance abuse, child seat belt, helmet use in relation to RTI prevention are missed in all systems. Accordingly, it is a critical need to integrate and establish a comprehensive surveillance system, with focus on the goal of each system and collection of minimum data in each organization, which currently is underway.


Assuntos
Acidentes de Trânsito/prevenção & controle , Acidentes de Trânsito/estatística & dados numéricos , Coleta de Dados/métodos , Gestão da Segurança/organização & administração , Ferimentos e Lesões/epidemiologia , Ferimentos e Lesões/prevenção & controle , Humanos , Irã (Geográfico)/epidemiologia , Sistema de Registros , Segurança
15.
Front Aging Neurosci ; 12: 99, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32372944

RESUMO

Alzheimer's disease (AD) is characterized by a sequence of pathological changes, which are commonly assessed in vivo using various brain imaging modalities such as magnetic resonance imaging (MRI) and positron emission tomography (PET). Currently, the most approaches to analyze statistical associations between regions and imaging modalities rely on Pearson correlation or linear regression models. However, these models are prone to spurious correlations arising from uninformative shared variance and multicollinearity. Notably, there are no appropriate multivariate statistical models available that can easily integrate dozens of multicollinear variables derived from such data, being able to utilize the additional information provided from the combination of data sources. Gaussian graphical models (GGMs) can estimate the conditional dependency from given data, which is conceptually expected to closely reflect the underlying causal relationships between various variables. Hence, we applied GGMs to assess multimodal regional brain alterations in AD. We obtained data from N = 972 subjects from the Alzheimer's Disease Neuroimaging Initiative. The mean amyloid load (AV45-PET), glucose metabolism (FDG-PET), and gray matter volume (MRI) were calculated for each of the 108 cortical and subcortical brain regions. GGMs were estimated using a Bayesian framework for the combined multimodal data and the resulted conditional dependency networks were compared to classical covariance networks based on Pearson correlation. Additionally, graph-theoretical network statistics were calculated to determine network alterations associated with disease status. The resulting conditional dependency matrices were much sparser (≈10% density) than Pearson correlation matrices (≈50% density). Within imaging modalities, conditional dependency networks yielded clusters connecting anatomically adjacent regions. For the associations between different modalities, only few region-specific connections were detected. Network measures such as small-world coefficient were significantly altered across diagnostic groups, with a biphasic u-shape trajectory, i.e., increased small-world coefficient in early mild cognitive impairment (MCI), similar values in late MCI, and decreased values in AD dementia patients compared to cognitively normal controls. In conclusion, GGMs removed commonly shared variance among multimodal measures of regional brain alterations in MCI and AD, and yielded sparser matrices compared to correlation networks based on the Pearson coefficient. Therefore, GGMs may be used as alternative to thresholding-approaches typically applied to correlation networks to obtain the most informative relations between variables.

16.
J Colloid Interface Sci ; 573: 317-327, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32289627

RESUMO

HYPOTHESIS: Alkyl ketene dimer (AKD) is frequently used in paper industry as an inexpensive sizing agent. The formation of a porous structure after curing the solidified AKD for an extra-long time (4-6 days) results in superhydrophobicity. In this study, a facile and low-cost method was utilized to turn the surface of AKD superhydrophobic in a very short period of time. EXPERIMENTS: We fabricated superhydrophobic coatings by dipping glass and paper substrates in molten AKD and then treating them with ethanol after solidification. The samples were characterized by X-ray diffraction, Scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy, Confocal laser scanning microscopy, and dynamic contact angle goniometry. FINDINGS: The results show that briefly treating the coatings, obtained from isothermally heated AKD melt at 40 °C for 3 min, with ethanol leads to superhydrophobicity with advancing and receding contact angles of 158.7 ± 1.4° and 156.8 ± 0.9°, respectively. By increasing the melt temperature to 70 °C and its heating time to 6 h followed by ethanol treatment, the advancing and receding contact angles increased to 163.7 ± 1.3° and 162.6 ± 1.2°, respectively. This enhancement in superhydrophobicity is due to the formation of porous, entangled irregular micro/nano textures that create air cushions on the surface resulting in droplet state transition from Wenzel to Cassie.

17.
Adv Mater ; 32(22): e2001330, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32319171

RESUMO

Collective excitation of periodic arrays of metallic nanoparticles by coupling localized surface plasmon resonances to grazing diffraction orders leads to surface lattice resonances with narrow line width. These resonances may find numerous applications in optical sensing and information processing. Here, a new degree of freedom of surface lattice resonances is experimentally investigated by demonstrating handedness-dependent excitation of surface lattice resonances in arrays of chiral plasmonic crescents. The self-assembly of particles used as mask and modified colloidal lithography is applied to produce arrays of planar and 3D gold crescents over large areas. The excitation of surface lattice resonances as a function of the interparticle distance and the degree of order within the arrays is investigated. The chirality of the individual 3D crescents leads to the formation of chiral lattice modes, that is, surface lattice resonances that exhibit optical activity.

18.
J Inj Violence Res ; 12(2)2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32319428

RESUMO

BACKGROUND: Development of construction and operation of subway rail transit system in populated cities of middle- and high-income countries along with the increasing population of its users, have exacerbated the safety problems of the users against incidents and emergencies in subway stations. Although subway emergency evacuation is considered by the governments and subway network organizations as a critical task related to passengers' safety at the time of emergency, the risk of mass evacuation in station is undeniable. The main objective of this study is to identify factors affecting safe evacuation of the population from subway station and to propose the strategies for addressing them based on experiences or opinions of stakeholders in Tehran Subways, Iran. METHODS: This is a qualitative study that was conducted between January 2017 and December 2018, in which a semi-structured interview was conducted for 17 participants among the senior managers, executive managers, subway station operations staff, and subway passengers in Tehran subway stations, in the Capital of Iran. In order to analyze the data of this qualitative study, the Graneheim and Lundman method was used and manifested content analysis approach was employed. RESULTS: Based on the findings of this study, the factors affecting safe evacuation of the population from subways station were identified in four main categories covering passengers, organization, communications, and environment. Then the main categories of "culture, interaction and cooperation of passengers", "correct and timely decision-making", "notification", and "location of emergency evacuation" were emerged as safe emergency evacuation challenges and the most important findings of this study; and strategies were proposed to improve the safety of passengers at emergency evacuation of subway stations. CONCLUSIONS: In the present study, the lack of safe approach to improving passengers' safety in the development plan of Tehran subway rail transit network is a major concern for managers and operations staff. Therefore, changing the attitude of policy makers from focusing on the quantitative development of passenger transportation services to improving safety and then the quality of passengers' trip is taken into account as an urgent need to improve the safety of subway passengers.

19.
Waste Manag ; 105: 373-383, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32120264

RESUMO

In the present research, application of waste edible oil (WEO) as a suitable and abundant source for biodiesel production using CaO@MgO nanocatalyst derived from waste chicken eggshells was studied. To this end, FT-IR, XRD, SEM, EDX, Map, and TEM analyses were performed to investigate characteristics of the CaO@MgO nanocatalyst. Also, the physical properties of the biodiesel such as flash point, kinematic viscosity, density, distillation point, cloud point, pour point, cetane number, oxidation stability, and acid number were determined according to the international standards. In addition, FT-IR and HNMR analyses were used to determine the biodiesel characteristics. Moreover, the produced catalyst was successively reused for up to 6 cycles and the results showed that the catalytic activity of the catalyst produced was sufficient for biodiesel production from WEO for up to three cycles, beyond which its catalytic activity decreased. The present work further considered the effects of different parameters on biodiesel production using central composite design to determine optimal conditions. According to the results, the highest biodiesel conversion yield (98.37%) was achieved in a reaction time of 7.08 h, reaction temperature of 69.37 °C, methanol-to-oil ratio of 16.7:1, and catalyst concentration of 4.571 wt% which shows the highest biodiesel conversion yield ever achieved from waste edible oil.


Assuntos
Biocombustíveis , Óxido de Magnésio , Animais , Compostos de Cálcio , Catálise , Esterificação , Óxidos , Óleos Vegetais , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Small ; 16(17): e1906463, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32182405

RESUMO

In the context of sensing and transport control, nanopores play an essential role. Designing multifunctional nanopores and placing multiple surface functionalities with nanoscale precision remains challenging. Interface effects together with a combination of different materials are used to obtain local multifunctionalization of nanoscale pores within a model pore system prepared by colloidal templating. Silica inverse colloidal monolayers are first functionalized with a gold layer to create a hybrid porous architecture with two distinct gold nanostructures on the top surface as well as at the pore bottom. Using orthogonal silane- and thiol-based chemistry together with a control of the wetting state allows individual addressing of the different locations within each pore resulting in nanoscale localized functional placement of three different functional units. Ring-opening metathesis polymerization is used for inner silica-pore wall functionalization. The hydrophobized pores create a Cassie-Baxter wetting state with aqueous solutions of thiols, which enables an exclusive functionalization of the outer gold structures. In a third step, an ethanolic solution able to wet the pores is used to self-assemble a thiol-containing initiator at the pore bottom. Subsequent controlled radical polymerization provides functionalization of the pore bottom. It is demonstrated that the combination of orthogonal surface chemistry and controlled wetting states can be used for the localized functionalization of porous materials.

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