58 research outputs found
The use of pulse-compression thermography for detecting defects in paintings
Interest in the conservation of paintings grows year by year. Their periodic inspection is essential for their conservation over the time. Thermographic non-destructive inspection is one technique useful for paintings, but it is essential to be able to detect buried defects while minimising the level of thermal stimulus. This paper describes a pulse-compression infrared thermography technique whereby defect detection is optimized while minimising the rise in temperature. To accomplish this task, LED lamps driven by a coded waveform based on a linear frequency modulated chirp signal have been used on paintings on both a wooden panel and a canvas layer. These specimens contained artificially fabricated defects. Although the physical condition of each painting was different, the experimental results show that the proposed signal processing procedure is able to detect defects using a low temperature contrast
Nonordered dendritic mesoporous silica nanoparticles as promising platforms for advanced methods of diagnosis and therapies
Dendritic mesoporous silica nanoparticles (DMSNs) are a new generation of porous materials that have gained great attention compared to other mesoporous silicas due to attractive properties, including straightforward synthesis methods, modular surface chemistry, high surface area, tunable pore size, chemical inertness, particle size distribution, excellent biocompatibility, biodegradability, and high pore volume compared with conventional mesoporous materials. The last years have witnessed a blooming growth of the extensive utilization of DMSNs as an efficient platform in a broad spectrum of biomedical and industrial applications, such as catalysis, energy harvesting, biosensing, drug/gene delivery, imaging, theranostics, and tissue engineering. DMSNs are considered great candidates for nanomedicine applications due to their ease of surface functionalization for targeted and controlled therapeutic delivery, high therapeutic loading capacity, minimizing adverse effects, and enhancing biocompatibility. In this review, we will extensively detail state-of-the-art studies on recent advances in synthesis methods, structure, properties, and applications of DMSNs in the biomedical field with an emphasis on the different delivery routes, cargos, and targeting approaches and a wide range of therapeutic, diagnostic, tissue engineering, vaccination applications and challenges and future implications of DMSNs as cuttingedge technology in medicine
Smart and biomimetic 3D and 4D printed composite hydrogels: opportunities for different biomedical applications
In recent years, smart/stimuli-responsive hydrogels have drawn tremendous attention for their varied applications, mainly in the biomedical field. These hydrogels are derived from different natural and synthetic polymers but are also composite with various organic and nano-organic fillers. The basic functions of smart hydrogels rely on their ability to change behavior; functions include mechanical, swelling, shaping, hydrophilicity, and bioactivity in response to external stimuli such as temperature, pH, magnetic field, electromagnetic radiation, and biological molecules. Depending on the final applications, smart hydrogels can be processed in different geometries and modalities to meet the complicated situations in biological media, namely, injectable hydrogels (following the sol-gel transition), colloidal nano and microgels, and three dimensional (3D) printed gel constructs. In recent decades smart hydrogels have opened a new horizon for scientists to fabricate biomimetic customized biomaterials for tissue engineering, cancer therapy, wound dressing, soft robotic actuators, and controlled release of bioactive substances/drugs. Remarkably, 4D bioprinting, a newly emerged technology/concept, aims to rationally design 3D patterned biological matrices from synthesized hydrogel-based inks with the ability to change structure under stimuli. This technology has enlarged the applicability of engineered smart hydrogels and hydrogel composites in biomedical fields. This paper aims to review stimuli-responsive hydrogels according to the kinds of external changes and t recent applications in biomedical and 4D bioprinting
Nonordered dendritic mesoporous silica nanoparticles as promising platforms for advanced methods of diagnosis and therapies
Dendritic mesoporous silica nanoparticles (DMSNs) are a new generation of porous materials that have gained great attention compared to other mesoporous silicas due to attractive properties, including straightforward synthesis methods, modular surface chemistry, high surface area, tunable pore size, chemical inertness, particle size distribution, excellent biocompatibility, biodegradability, and high pore volume compared with conventional mesoporous materials. The last years have witnessed a blooming growth of the extensive utilization of DMSNs as an efficient platform in a broad spectrum of biomedical and industrial applications, such as catalysis, energy harvesting, biosensing, drug/gene delivery, imaging, theranostics, and tissue engineering. DMSNs are considered great candidates for nanomedicine applications due to their ease of surface functionalization for targeted and controlled therapeutic delivery, high therapeutic loading capacity, minimizing adverse effects, and enhancing biocompatibility. In this review, we will extensively detail state-of-the-art studies on recent advances in synthesis methods, structure, properties, and applications of DMSNs in the biomedical field with an emphasis on the different delivery routes, cargos, and targeting approaches and a wide range of therapeutic, diagnostic, tissue engineering, vaccination applications and challenges and future implications of DMSNs as cutting-edge technology in medicine
Proceedings of the Eighth Annual Deep Brain Stimulation Think Tank: Advances in Optogenetics, Ethical Issues Affecting DBS Research, Neuromodulatory Approaches for Depression, Adaptive Neurostimulation, and Emerging DBS Technologies
We estimate that 208,000 deep brain stimulation (DBS) devices have been implanted to address neurological and neuropsychiatric disorders worldwide. DBS Think Tank presenters pooled data and determined that DBS expanded in its scope and has been applied to multiple brain disorders in an effort to modulate neural circuitry. The DBS Think Tank was founded in 2012 providing a space where clinicians, engineers, researchers from industry and academia discuss current and emerging DBS technologies and logistical and ethical issues facing the field. The emphasis is on cutting edge research and collaboration aimed to advance the DBS field. The Eighth Annual DBS Think Tank was held virtually on September 1 and 2, 2020 (Zoom Video Communications) due to restrictions related to the COVID-19 pandemic. The meeting focused on advances in: (1) optogenetics as a tool for comprehending neurobiology of diseases and on optogenetically-inspired DBS, (2) cutting edge of emerging DBS technologies, (3) ethical issues affecting DBS research and access to care, (4) neuromodulatory approaches for depression, (5) advancing novel hardware, software and imaging methodologies, (6) use of neurophysiological signals in adaptive neurostimulation, and (7) use of more advanced technologies to improve DBS clinical outcomes. There were 178 attendees who participated in a DBS Think Tank survey, which revealed the expansion of DBS into several indications such as obesity, post-traumatic stress disorder, addiction and Alzheimer’s disease. This proceedings summarizes the advances discussed at the Eighth Annual DBS Think Tank
Immobilization of gold nanoparticles on folate-conjugated dendritic mesoporous silica-coated reduced graphene oxide nanosheets: a new nanoplatform for curcumin pH-controlled and targeted delivery.
A nanocarrier for curcumin targeted delivery and cell imaging was prepared by immobilization of gold NPs on the folic acid-modified dendritic mesoporous silica-coated reduced graphene oxide nanosheets.</p
Moisture and temperature induced swelling/shrinkage of softwood and hardwood glulam and LVL: An experimental study
To investigate the hygroscopic behaviour of engineered timber, glued-laminated (glulam) timber made of Pacific Teak (Tectona grandis), Tasmanian Oak (Eucalyptus regnans/obliqua/delegatensis), Blackbutt (Eucalyptus pilularis), Radiata Pine (Pinus radiata) and Slash Pine (Pinus elliottii) and laminated veneer lumber (LVL) made of Radiata Pine were exposed to sorption and desorption cycles at two temperatures (i.e. 15 and 50 °C) and the shrinkage and swelling of samples were measured in three orthogonal directions. The samples were conditioned in different relative humidity to produce eight intermediate moisture contents (reading points) between the oven-dried and saturated states. A bilinear model was fitted to the swelling/shrinkage strain-moisture content data to accurately determine the Coefficient of Moisture Expansion (CME) and Moisture Contraction (CMC), and Coefficient of Thermal Expansion (CTE), as well as the Fibre Saturation Point (FSP) for each group of specimens. The experimental results demonstrated a significant difference in swelling/shrinkage behaviour of large glulam and LVL samples compared to small clear wood samples as well as a significant effect of temperature on moisture-induced swelling/shrinkage of glulam and LVL beams in the transverse direction. The CME and/or CMC in the transverse direction were found to decrease with increasing temperature, while swelling/shrinkage coefficients in the longitudinal direction exhibited an opposite pattern. The results of this study can potentially improve the accuracy of the hygro-thermo-mechanical and long-term analysis of glulam and LVL members
Role of Membership in Forestry Cooperatives for Utilization of Forestry Resources in the Western Mazandaran
In the recent decades, numerous countries, including Iran, have been considering grassroots participation in exploiting natural resources as an effective strategy. In this regard, the cooperative model of participation in north of Iran, particularly in the western part of Mazandaran Province was tested. The main purpose of this study was to assess the role of membership in forestry cooperatives in the exploitation of forestry resources in the western part of Mazandaran province. It was a correlational – descriptive study conducted through the survey method. The sample consisted of 75 members of forestry cooperatives and 76 of non-members. Validity and reliability of the data gathering instrument were conformed through appropriate methods. The result of "T" test indicated that the two groups i.e.. members and non-members had significant difference of participation in exploitation of forest resources. According to correlation analysis there were significant relation between membership & participation in exploitation of forestry resources. Also, the result produced by multivariate regression Analysis indicated that 66.8 percent of the changes in conservation was accounted by their participation in conservation and development of forest resources
Comparison of time and frequency domain features’ immunity against lift-off in pulse-compression eddy current imaging
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