Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Nanotechnology ; 34(36)2023 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-37285818

RESUMEN

The cooling of devices is a big challenge in the electronics industry, and most process units (graphical are central process units) experience defects under harsh temperature conditions, so dissipating generated heat under various working conditions should be studied seriously. This study investigates the magnetohydrodynamics of hybrid ferro-nanofluids in the presence of hydrophobic surfaces in a micro-heat sink. To scrutinize this study, a finite volume method (FVM) is applied. The ferro-nanofluid includes water as a base fluid and multiwall carbon nanotubes (MWCNTs) and Fe3O4as nanoadditives, which are used in three concentrations (0, 1, and 3%). Other parameters such as the Reynolds number (5-120), Hartmann number (magnitude of the magnetic field from 0 to 6), and hydrophobicity of surfaces are scrutinized for their impacts on heat transfer and hydraulic variables as well as entropy generation variables. The outcomes indicate that increasing the level of hydrophobicity in surfaces leads simultaneously to improved heat exchange and reduced pressure drop. Likewise, it decreases the frictional and thermal types of entropy generation. Intensifying the magnitude of the magnetic field enhances the heat exchange as much as the pressure drop. It can also decrease the thermal term in entropy generation equations for the fluid, but increase the frictional entropy generation and adds a new term, magnetic entropy generation. Incrementing the Reynolds number improves the convection heat transfer parameters, although it intensifies the pressure drop in the length of the channel. Also, the thermal entropy generation and frictional entropy generation decrease and increase with an increasing flow rate (Reynolds number).


Asunto(s)
Calor , Nanotubos de Carbono , Entropía , Campos Magnéticos , Interacciones Hidrofóbicas e Hidrofílicas
2.
Neurocomputing (Amst) ; 523: 116-129, 2023 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-37332394

RESUMEN

Dense pixel matching problems such as optical flow and disparity estimation are among the most challenging tasks in computer vision. Recently, several deep learning methods designed for these problems have been successful. A sufficiently larger effective receptive field (ERF) and a higher resolution of spatial features within a network are essential for providing higher-resolution dense estimates. In this work, we present a systemic approach to design network architectures that can provide a larger receptive field while maintaining a higher spatial feature resolution. To achieve a larger ERF, we utilized dilated convolutional layers. By aggressively increasing dilation rates in the deeper layers, we were able to achieve a sufficiently larger ERF with a significantly fewer number of trainable parameters. We used optical flow estimation problem as the primary benchmark to illustrate our network design strategy. The benchmark results (Sintel, KITTI, and Middlebury) indicate that our compact networks can achieve comparable performance in the class of lightweight networks.

3.
BMC Public Health ; 22(1): 1148, 2022 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-35676671

RESUMEN

AIM: The objective of this study was to develop a cultural adopted questionnaire for evaluation of knowledge (K), attitude (A) and practice (P) of Iranian population toward food safety during Covid-19. METHODS: The study is based on an online questionnaire that filled by 712 Iranians over 16 years old. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and reliability assessment were performed. The construct validity of A and P determined by EFA and confirmed by CFA. Difficulty index was used for K. RESULTS: The reliability score of questionnaire was satisfactory. The three items of K-A-P questionnaire were significantly associated with the total score of questionnaire. The KAP questionnaire regarding food safety in covid-19 consisted of 27 items multidimensional scale with strong psychometric features. The respondent showed a satisfactory level of KAP during covid-19 pandemics. CONCLUSION: The KAP questionnaire regarding food safety in covid-19 is a valid and reliable tool for measurement of knowledge, attitude and practice of people regarding food safety in covid-19.


Asunto(s)
COVID-19 , Adolescente , COVID-19/epidemiología , Inocuidad de los Alimentos , Conocimientos, Actitudes y Práctica en Salud , Humanos , Higiene , Irán/epidemiología , Pandemias/prevención & control , Psicometría/métodos , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
4.
ScientificWorldJournal ; 2022: 3885745, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36132437

RESUMEN

Sustained bioenergy production from organisms that thrive in high salinity, low oxygen, and low nutrition levels is useful in monitoring hypersaline polluted environments. Microbial fuel cell (MFC) studies utilizing single species halophiles under salt concentrations higher than 1 M and as a closed microbial system are limited. The current study aimed to establish baseline voltage, current, and power density from a dual-chambered MFC utilizing the halophile Halobacterium salinarum NRC-1. MFC performance was determined with two different electrode sizes (5 cm2 and 10 cm2), under oscillating and nonoscillating conditions, as well as in a stacked series. A closed dual-chamber MFC system of 100 mL capacity was devised with Halobacterium media (4.3 M salt concentration) as both anolyte and catholyte, with H. salinarum NRC-1 being the anodic organism. The MFC measured electrical output over 7, 14, 28, and 42 days. MFC output increased with 5 cm2 sized electrodes under nonoscillating (p < 0.0001) relative to oscillating conditions. However, under oscillating conditions, doubling the electrode size increased MFC output significantly (p = 0.01). The stacked series MFC, with an electrode size of 10 cm2, produced the highest power density (1.2672 mW/m2) over 14 days under oscillation. Our results highlight the potentiality of H. salinarum as a viable anodic organism to produce sustained voltage in a closed-MFC system.


Asunto(s)
Fuentes de Energía Bioeléctrica , Electricidad , Electrodos , Halobacterium salinarum , Oxígeno
5.
Am J Dent ; 35(2): 75-78, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35506961

RESUMEN

PURPOSE: To evaluate the failure rate of 1,000 immediately placed implants in fresh extraction sockets and their risk factors. METHODS: The data comprised files of 1,000 fresh socket implants placed during the 2014-2019 interval in three Tehran-based private dental clinics. The statistical method was survival analysis consisting of shared frailty and intra-cluster correlation. Moreover, Chi-squared test and Mann-Whitney U test were used to statistically analyze the relationship between each independent variable and the response variable (immediate implant failure). RESULTS: 40 cases of failures among the implants were found, accounting for a 4% failure rate. Shared frailty survival model indicated that only the implant system significantly affects the failure rate. Intra-clustered correlation was 0.41. Chi-squared analysis showed that gender and implant system both significantly affect immediate implant failure. None of the quantitative variables were significantly related to immediate implant failure according to the Mann-Whitney U test. CLINICAL SIGNIFICANCE: The data was gathered using a relatively large sample size to perform a reliable evaluation on success and predictability of implants placed into fresh extraction sites. A brief review on articles focusing on fresh socket implant success or failure published from years 2000-2020 is presented.


Asunto(s)
Implantes Dentales , Fragilidad , Carga Inmediata del Implante Dental , Fracaso de la Restauración Dental , Estudios de Seguimiento , Humanos , Carga Inmediata del Implante Dental/métodos , Irán , Estudios Retrospectivos , Factores de Riesgo , Extracción Dental , Alveolo Dental/cirugía , Resultado del Tratamiento
6.
J Cell Physiol ; 236(7): 5306-5316, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33377240

RESUMEN

Herbal-derived three-dimensional scaffolds have a unique structure that represents the natural cellular microenvironment and can be potentially used for tissue engineering applications. In the present study, cabbage (Cb) leaves were decellularized and then their characteristics, such as surface roughness, wettability, porosity, mechanical properties, and specific surface area, were investigated. After that, scaffold osteoinductivity was studied by bone-marrow-derived mesenchymal stem cells (BM-MSCs) osteogenic differentiation while growing on the decellularized Cb leaves. Cells mineralization, calcium secretion, alkaline phosphatase (ALP) activity, and expression levels of bone-related genes were determined during the differentiation process. Our results from the structural characterization of the scaffolds demonstrated that decellularized Cb leaves are good candidates for bone differentiation in terms of surface roughness, mechanical properties, and interconnected pores. Osteogenic differentiation evaluation of the BM-MSCs determined that the cell's ALP activity and mineralization were increased significantly while cultured on the decellularized Cb leaves compared to the cells cultured on the culture plate as a control. Besides, Runx2, ALP, collagen-1 (Col-I), and osteocalcin genes were expressed in cells cultured on decellularized Cb leaves significantly higher than cells cultured on the culture plate. Based on these results, it can be concluded that the decellularized Cb scaffold has great potential for promoting BM-MSCs proliferation and osteogenic differentiation.


Asunto(s)
Células de la Médula Ósea , Brassica , Células Madre Mesenquimatosas , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Diferenciación Celular , Celulosa , Humanos , Osteogénesis/fisiología
7.
Environ Monit Assess ; 193(8): 540, 2021 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-34331145

RESUMEN

The polycyclic aromatic hydrocarbon (PAH) content of the Tahdig of the breads and potatoes prepared with edible oil was determined by GC-MS. The Tahdigs of bread and potato were baked under the same condition (volume of any oil 40 cc, temperature 180 °C, time 30 min). Polycyclic aromatic hydrocarbon determination was performed by an Agilent 6890 N Gas chromatography with mass selective detector, equipped with a capillary column. The highest contents of PAHs in Tahdig of bread and Tahdig of potato were observed in canola with 550 ± 3.9 ng/kg and sesame with 408.3 ± 41 ng/kg. The mean of PAH content was significantly higher in the Tahdig of bread compared to the Tahdig of potato (p < 0.05). Among the 16 PAHs examined by GC/MS, 10 PAHs were detected. The amount of high molecular weight (HMW) PAHs were significantly more than low molecular weight (LMW) PAHs (p < 0.05). Benzo [b]fluoranthene and benz[a]anthracene concentrations were significantly more than the other detected compounds (p < 0.05). Due to high PAH contamination of both Tahdig groups, the consumption of Tahdig (any type) was not recommended.


Asunto(s)
Hidrocarburos Policíclicos Aromáticos , Solanum tuberosum , Pan , Monitoreo del Ambiente , Cromatografía de Gases y Espectrometría de Masas , Hidrocarburos Policíclicos Aromáticos/análisis
8.
Int J Comput Dent ; 23(4): 317-323, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33491927

RESUMEN

AIM: The aim of the present study was to compare six different methods of in vivo color matching: visual shade matching (3D-Master Linearguide shade guide) performed by 1) a novice practitioner, 2) an expert practitioner, 3) the new Rayplicker spectrometer, 4) the Trios III intraoral scanner, and 5) the Omnicam intraoral scanner compared with 6) the Easyshade V spectrophotometer, which was considered as the reference. MATERIALS AND METHODS: Color matching was performed using the 3D-Master references on the sound maxillary right central incisors of 40 subjects. The study first compared the number of colors found using each of the six methods. The references were then converted to the Commission Internationale de l'Eclairage (CIE) L*a*b* values, from which the difference ?E between either two methods ?was derived. Finally, the L* value was used to compare the luminosity measured by each of the six methods. RESULTS: The Rayplicker showed the smallest ?E compared with the Easyshade V. The expert found a closer color to the Easyshade V than did the novice, and both were closer to the Easyshade V than the two intraoral scanners. The intraoral scanners showed notable differences compared with the Easyshade V. The intraoral scanners also offered a reduced choice of colors and recorded the highest luminosities compared with the other methods. CONCLUSION: Within the limitations of this study, the color matching by the Rayplicker was closest to that of the Easyshade V. The good performance of this new device means that it is a challenging competitor for the Easyshade V. Finally, the new methods based on intraoral scanners were less reliable than the spectrophotometers and the visual shade matching.


Asunto(s)
Percepción de Color , Coloración de Prótesis , Color , Humanos , Incisivo , Espectrofotometría
9.
J Chem Phys ; 149(19): 194901, 2018 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-30466268

RESUMEN

We develop a general framework for transport of polyions, solvent and salt, with intended application to Layer-by-Layer (LbL) assembly of polyelectrolyte monolayers (PEMs). The formulation for the first time includes electrostatics, chemical potential gradients, and mechanical stress gradients as driving forces for mass transport. The general model allows all species to be mobile throughout the process and avoids the assumptions of stepwise instantaneous equilibrium and/or immobilized structures typical of previous approaches, while reducing to these models in appropriate limits. A simple constitutive equation is derived for a mixture of oppositely charged polyelectrolytes that accounts for network strand dilution and cross-chain ion pairing by appending reactive terms to the Smoluchowski probability diffusion equation for network strand end-to-end vectors. The resulting general framework encompasses the Poisson equation describing the electrostatic potential distribution, an osmotic pressure balance, a stress constitutive equation, and a generalized flux law of polymer transport. The computational domain is split into a PEM phase and an external solution phase with an appropriate boundary condition derived for the interface between the two. The mobile species (water and small salt ions) are taken to be in a state of dynamic equilibrium with their distributions enslaved to the perturbations in the two polyion compositions. The proposed model captures the swelling response of PEM films to external solutions. For the first time, we studied the effects of the temporal evolution of electrostatic and stress distribution on the rate of chain loss and absorption during rinsing and dipping of an idealized and arbitrarily selected and rigid brush layer into external solutions. The temporal evolution provides a kinetic basis for the ability of LbL films to grow under conditions that thermodynamics alone suggests would cause them to be washed away and to account for partial desorption during washing. The proposed transport framework constitutes a solid basis for eventual quantitative modeling of LbL assembly and transport in polyion networks more generally.

10.
J Chem Phys ; 149(16): 163335, 2018 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-30384694

RESUMEN

Reversible ion binding equilibria in polyelectrolyte solutions are strongly affected by interactions between dissociated ionic species. We examine how the structural correlations between ionic groups on polyelectrolytes impact the counterion binding. Treating the electrostatic correlation free energy using the classical Debye-Hückel expression leads to complete counterion dissociation in the concentrated regime. This unphysical behavior is shown to stem from improper regularization of the self-energy of dissociated ions and polyions and is mitigated by smearing point-like charges across a finite width. The influence of the self-energy on counterion binding is elaborated on by generalizing the Debye-Hückel free energy to polyelectrolytes with variable fractal dimension and stiffness. In the dilute regime, a greater propensity for binding is found for chains with more compact architectures, which in turn reduces the harsh self-repulsions of tightly packed arrangements of charge. In the concentrated regime, the effects of electrostatic correlations weaken due to screening and the extent of binding is governed by a balance of short-ranged interactions and the translational entropy of ions.

11.
J Environ Manage ; 210: 131-138, 2018 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-29339331

RESUMEN

The present study evaluates the efficacy of S-doped MgO (S-MgO) as compared with the plain MgO as a catalyst for destructive removal of tetracycline (TTC) in aqueous solutions. The S-MgO had around 6% S in its structure. Doping MgO with S caused increase in surface oxygen vacancy defects. Adding S-MgO (12 g/L) to a TTC aqueous solution (50 mg/L) caused removal of around 99% TTC at the neutral pH (ca. 5.1) and a short reaction time of 10 min. In comparison, plain MgO could remove only around 15% of TTC under similar experimental conditions. Diffusing O2 into the TTC solution under the reaction with S-MgO resulted in a considerable improvement of TTC removal as compared to diffusing N2. Complete removal of TTC and 86.4% removal of its TOC could be obtained using 2 g/L S-MgO nanoparticles. The removal of TTC increased with the increase in solution temperature. The presence of nitrate, sulfate and chloride did not considerably affect the removal of TTC using S-MgO while TTC removal significantly decreased at the presence of bicarbonate and phosphate. The S-MgO was a stable and reusable catalyst exhibiting much higher catalytic activity than plain MgO for the TTC destruction. Accordingly, S-MgO is an emerging and efficient catalyst for catalytic decomposition and mineralization of such pharmaceutical compounds as TTC under atmospheric temperature and pressure.


Asunto(s)
Manganeso , Nanopartículas , Tetraciclina/química , Purificación del Agua , Antibacterianos , Compuestos de Manganeso , Óxidos , Azufre
12.
Cutan Ocul Toxicol ; 37(1): 9-14, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28486855

RESUMEN

PURPOSE: The aim of this study is to compare the effect of smoking in corneal endothelial cell number and morphology by specular microscopy on a non-smoker population. METHODS: Our cross-sectional study was performed on 150 participants from a non-smoker population. Non-contact specular microscopy (Tomey Corporation Inc., Nagoya, Japan) was performed in the center of the cornea of all subjects. The cell density (CD), average cell size (AVG), percent of hexagonality (HEX%) and central corneal thickness (CCT) were calculated and compared in both groups. RESULTS: Totally, 76 eyes of 76 smokers and 74 eyes of 74 non-smokers were enrolled in the study from 2015 to 2016. The mean age of smokers and non-smokers were 48.61 ± 17.04 and 46.39 ± 13.02, respectively. The mean number of pack/year among the smokers was 17.36 ± 14.68. Also, the mean values of AVG and CD were significantly different for these two groups (p = 0.011 and p = 0.039, respectively). Other corneal endothelial variables did not show a significant difference between smokers and non-smokers (p > 0.05). However, smokers with severe nicotine dependency had significantly greater AVG and lower CD in comparison with the non-smokers (p = 0.004 and p = 0.013, respectively). CONCLUSION: Our study showed that smoking can cause significant changes in some of the corneal endothelial variables, but not all of them.


Asunto(s)
Células Endoteliales/citología , Endotelio Corneal/citología , Fumar/epidemiología , Tabaquismo/epidemiología , Adulto , Anciano , Recuento de Células , Tamaño de la Célula , Estudios Transversales , Femenino , Humanos , Irán/epidemiología , Masculino , Persona de Mediana Edad , Estrés Oxidativo
13.
Med J Islam Repub Iran ; 32: 74, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30643749

RESUMEN

Background: One of the vulnerable populations of any community are the elderly, who are exposed to poor balance, falls, injuries, reduced quality of life (QoL) and independency, and early death. Considering the importance of balance in independently performing activities of daily living (ADL) and its impact on QoL, in this study, we aimed at investigating the effect of Cawthorne and Cooksey exercises (CCE) on QoL and balance of 60 to 80 year-old individuals in Shiraz, Iran. Methods: This clinical trial study was conducted on forty 80 to 60-year-old individuals of Jahandideghan retirement center in Shiraz (20 in the intervention and 20 in the control groups) in 2014. The intervention group did CCE in three 60- minute sessions a week for 2 months. The balance status of the participants was assessed with Berg balance test, and their QoL was also examined using SF36 Quality of Life Questionnaire before the intervention and at 2 months post intervention. Data were analyzed by independent t test in SPSS software Version 19. Results: The results of the study revealed that the difference was significant in the balance change scores between the 2 groups (p<0.001, effect size = 0.78). Change differences in the QoL scores were significant between the 2 groups as well (p<0.001, effect size = 0.39). Conclusion: CCT improved QoL and balance of 60 to 80 year- old Shirazians, so considering the low cost, easy implementation, and considerable impact of the exercises, CCT could be used to prevent and treat balance disorders of the elderly.

14.
Chemphyschem ; 18(1): 128-141, 2017 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-27862821

RESUMEN

The growth rates of layer-by-layer (LbL) assemblies of polyelectrolytes (PEs) with oppositely charged polystyrene (PS) nanoparticles (NPs) as a function of molecular weight (MW) of the PEs, ionic strength of the media, and NP size and charge are systematically investigated. To optimize LbL growth, the effects of suspension concentration, pH of the media, and deposition time on the growth rate of multilayers are assessed. Both linear and exponential growth behaviors are observed and, under optimal conditions, films of up to around 1 µm thick can readily be assembled after 10 or so bilayers have been deposited. For many of the cases studied, an intermediate MW of PE leads to the fastest film buildup, for both cationic poly(ethyleneimine) deposited alternately with anionic PS NPs and for anionic poly(acrylic acid) deposited alternately with cationic PS NPs. The existence of an optimal MW suggests that growth rate is determined by a balance of thermodynamic factors, including density of polymer bridges between particles, and kinetic factors, specifically the diffusivity of polymer in the film. The optimal MW, however, is very sensitive to the materials used. Moreover, depending on the MW of the PE, increasing salinity could increase or decrease the growth kinetics. Finally, the surface morphology of the films is characterized with AFM and SEM to reveal that the roughness increases less than linearly with film thickness.

15.
Med Oncol ; 41(2): 62, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38253748

RESUMEN

Acute myeloid leukemia (AML) is a fast-growing blood cancer that interferes with the normal growth of blood cells in the bone marrow and blood. It is characterized by its unpredictable outlook and high death rate. The main treatment for AML is chemotherapy, but this often results in drug resistance and the possibility of the disease returning. For this reason, new biomarkers are necessary to diagnose, predict, and treat this disease. Research has demonstrated that cells responsible for AML release exosomes that interact with the disease's microenvironment. These exosomes have significant roles in promoting leukemia growth, suppressing normal hematopoiesis, facilitating angiogenesis, and contributing to drug resistance in AML. Further investigations have shown that these exosomes contain miRNAs, which are transferred to target cells and have functional roles. Biomarkers are utilized to assess various aspects of tumor cell behavior, including proliferation, apoptosis, angiogenesis, changes in the microenvironment, transfer of drug resistance, and stability in serum and blood plasma. In this research, we showed that exosomal miRNAs and exosomes have the potential to be used as indicators for detecting various phases of AML and can aid in its medical treatment. Furthermore, they can be specifically targeted for therapeutic purposes in addressing this condition.


Asunto(s)
Exosomas , Leucemia Mieloide Aguda , MicroARNs , Humanos , MicroARNs/genética , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Apoptosis , Exosomas/genética , Biomarcadores , Microambiente Tumoral/genética
16.
J Biomater Sci Polym Ed ; 35(8): 1214-1235, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38431849

RESUMEN

Biologization of biomaterials with endothelial cells (ECs) is an important step in vascular tissue engineering, aiming at improving hemocompatibility and diminishing the thrombo-inflammatory response of implants. Since subcellular topography in the scale of nano to micrometers can influence cellular adhesion, proliferation, and differentiation, we here investigate the effect of surface roughness on the endothelialization of gelatin hydrogel scaffolds. Considering the micron and sub-micron features of the different native tissues underlying the endothelium in the body, we carried out a biomimetic approach to replicate the surface roughness of tissues and analyzed how this impacted the adhesion and proliferation of human umbilical endothelial cells (HUVECs). Using an imprinting technique, nano and micro-roughness ranging from Sa= 402 nm to Sa= 8 µm were replicated on the surface of gelatin hydrogels. Fluorescent imaging of HUVECs on consecutive days after seeding revealed that microscale topographies negatively affect cell spreading and proliferation. By contrast, nanoscale roughnesses of Sa= 402 and Sa= 538 nm promoted endothelialization as evidenced by the formation of confluent cell monolayers with prominent VE-cadherin surface expression. Collectively, we present an affordable and flexible imprinting method to replicate surface characteristics of tissues on hydrogels and demonstrate how nanoscale roughness positively supports their endothelialization.


Asunto(s)
Adhesión Celular , Proliferación Celular , Gelatina , Células Endoteliales de la Vena Umbilical Humana , Hidrogeles , Propiedades de Superficie , Andamios del Tejido , Humanos , Gelatina/química , Hidrogeles/química , Andamios del Tejido/química , Proliferación Celular/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Ingeniería de Tejidos , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología
17.
Sci Rep ; 14(1): 8217, 2024 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-38589481

RESUMEN

The present study of a novel metal-organic framework containing Fe single atoms doped on electrospun carbon nanofibers (Fe SA-MOF@CNF) based on dispersive micro solid phase extraction (D-µ-SPE) using HPLC-PDA for detection tartrazine in fake saffron samples was designed. The Fe SA-MOF@CNF sorbent was extensively characterized through various techniques including N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The specific area of surface of the sorbent was 577.384 m2/g. The study variables were optimized via the central composite design (CCD), which included a sorbent mass of 15 mg, a contact time of 6 min, a pH of 7.56, and a tartrazine concentration of 300 ng/ml. Under the optimum condition, the calibration curve of this method was linear in the range of 5-1000 ng/mL, with a correlation coefficient of 0.992. The LOD and LOQ values were ranged 0.38-0.74 and 1.34-2.42 ng/ml, respectively. This approach revealed significant improvements, including high extraction recovery (98.64), recovery rates (98.43-102.72%), and accuracy (RSDs < 0.75 to 3.6%). the enrichment factors were obtained in the range of 80.6-86.4 with preconcentration factor of 22.3. Consequently, the D-µ-SPE method based on synthesized Fe SA-MOF@CNF could be recommended as a sustainable sorbent for detecting tartrazine in saffron samples.


Asunto(s)
Crocus , Estructuras Metalorgánicas , Tartrazina , Cromatografía Líquida de Alta Presión/métodos , Extracción en Fase Sólida/métodos , Colorantes
18.
Clin Orthop Relat Res ; 471(10): 3149-57, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23529635

RESUMEN

BACKGROUND: The rate of release of an antibiotic from an antibiotic-loaded polymethylmethacrylate (PMMA) bone cement is low. This may be increased by adding a particulate poragen (eg, xylitol) to the cement powder. However, the appropriate poragen amount is unclear. QUESTIONS/PURPOSES: We explored the appropriate amount of xylitol to use in a PMMA bone cement loaded with daptomycin and xylitol. METHODS: We prepared four groups of cement, each comprising the same amount of daptomycin in the powder (1.36 g/40 g dry powder) but different amounts of xylitol (0, 0.7, 1.4, and 2.7 g); the xylitol mass ratio (X) (mass divided by mass of the final dry cement-daptomycin-xylitol mixture) ranged from 0 to 6.13 wt/wt%. Eight mechanical, antibiotic release, and bacterial inhibitory properties were determined using three to 22 specimens or replicates per test. We then used an optimization method to determine an appropriate value of X by (1) identifying the best-fit relationship between the value of each property and X, (2) defining a master objective function incorporating all of the best fits; and (3) determining the value of X at the maximum master objective function. RESULTS: We found an appropriate xylitol amount to be 4.46 wt/wt% (equivalent to 1.93 g xylitol mixed with 1.36 g daptomycin and 40 g dry cement powder). CONCLUSIONS: We demonstrated a method that may be used to determine an appropriate xylitol amount for a daptomycin-xylitol-loaded PMMA bone cement. These findings will require in vivo confirmation. CLINICAL RELEVANCE: While we identified an appropriate amount of xylitol in a daptomycin-xylitol-loaded PMMA bone cement as a prophylactic agent in total joint arthroplasties, clinical evaluations are needed to confirm the effectiveness of this cement.


Asunto(s)
Antibacterianos/administración & dosificación , Cementos para Huesos/química , Daptomicina/administración & dosificación , Portadores de Fármacos , Xilitol/administración & dosificación , Humanos
19.
Acta Cytol ; 57(6): 646-51, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24107477

RESUMEN

OBJECTIVE: Keratoconus (KC) is an eye disorder in which the cornea is swollen, thinned and deformed. Despite extensive studies, the pathophysiological processes and genetic etiology of KC are unknown. The disease incidence is approximately 1 in 2,000, and it is the most common cause of corneal transplantation in the USA. Many genes are involved in the disease, but evidence suggests a major role for VSX1 in the etiology of KC. This study aimed to determine the frequency of mutations in exons 2, 3 and 4 of the VSX1 gene in Chaharmahal va Bakhtiari province in the southwest of Iran. STUDY DESIGN: In this experimental study, mutations in 3 exons, namely exons 2, 3 and 4, of VSX1 were investigated in 50 patients with KC and 50 healthy control subjects. DNA was extracted using a standard phenol-chloroform method. PCR-single-strand conformational polymorphism/heteroduplex analysis was performed, followed by DNA sequencing to confirm the identified motility shifts. RESULTS: H244R mutations were found in 1 patient and also in 1 healthy control subject. Furthermore, 12 polymorphisms were identified in patients with KC and 7 in healthy control subjects [rs6138482 and c.546A>G (rs12480307)]. CONCLUSION: Our investigation showed that KC-related VSX1 mutations were found in a very small proportion of the studied patients from Iran. Further investigations on other genes are needed to clarify their roles in KC pathogenesis.


Asunto(s)
Proteínas del Ojo/genética , Análisis Heterodúplex/métodos , Proteínas de Homeodominio/genética , Queratocono/genética , Mutación , Secuencia de Bases , Análisis Mutacional de ADN , Humanos , Irán , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , Polimorfismo Conformacional Retorcido-Simple
20.
Eye (Lond) ; 37(18): 3819-3826, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37330606

RESUMEN

PURPOSE: To present a new structural biomarker for detecting glaucoma progression based on structural transformation of the optic nerve head (ONH) region over time. METHODS: Dense ONH deformation was estimated using deep learning methods namely DDCNet-Multires, FlowNet2, and FlowNetCorrelation, and legacy computational methods namely the topographic change analysis (TCA) and proper orthogonal decomposition (POD) methods. A candidate biomarker was estimated as the average magnitude of deformation of the ONH and evaluated using longitudinal confocal scans of 12 laser treated and 12 contralateral normal eyes of 12 primates from the LSU Experimental Glaucoma Study (LEGS); and 36 progressing eyes and 21 longitudinal normal eyes from the UCSD Diagnostic Innovations in Glaucoma Study (DIGS). Area under the ROC curve (AUC) was used to assess the diagnostic accuracy of the biomarker. RESULTS: AUROC (95% CI) for LEGS were: 0.83 (0.79, 0.88) for DDCNet-Multires; 0.83 (0.78, 0.88) for FlowNet2; 0.83 (0.78, 0.88) for FlowNet-Correlation; 0.94 (0.91, 0.97) for POD; and 0.86 (0.82, 0.91) for TCA methods. For DIGS: 0.89 (0.80, 0.97) for DDCNet-Multires; 0.82 (0.71, 0.93) for FlowNet2; 0.93 (0.86, 0.99) for FlowNet-Correlation; 0.86 (0.76, 0.96) for POD; and 0.86 (0.77, 0.95) for TCA methods. Lower diagnostic accuracy of the learning-based methods for LEG study eyes were due to image alignment errors in confocal sequences. CONCLUSION: Deep learning methods trained to estimate generic deformation were able to estimate ONH deformation from image sequences and provided a higher diagnostic accuracy. Our validation of the biomarker using ONH sequences from controlled experimental conditions confirms the diagnostic accuracy of the biomarkers observed in the clinical population. Performance can be further improved by fine-tuning these networks using ONH sequences.


Asunto(s)
Glaucoma , Disco Óptico , Animales , Tomografía de Coherencia Óptica/métodos , Glaucoma/diagnóstico , Fibras Nerviosas , Biomarcadores , Presión Intraocular
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA