جستجوی مقالات مرتبط با کلیدواژه "فناوری نانو" در نشریات گروه "پزشکی"

Due to uncertainties regarding the risks of engineered nanomaterials for human health and the environment, different organizations and researchers have developed various management frameworks and assessment tools to mitigate hazards during the procedures and applications of engineered nanomaterials. However, most of these techniques do not meet all the individual requirements. This study provides a review and introduction to the techniques developed for the management of safety, health, and environmental risks associated with engineered nanomaterials.

In order to find pertinent documents on the safe handling of engineered nanomaterials, a search was conducted using the following keywords: “Engineered nanomaterials”, “Framework”, “Tool”, “Risk management”, “Occupational exposure”, “Environment”, “Risk assessment”, and “Nanotechnology”. The search was conducted on various databases, including Scopus, Web of Science, NIOSH, ECHA, and ISO. Among the search results, tools and frameworks that specifically focus on the safety, health, and environmental risk management or assessment of engineered nanomaterials were selected.

Among the search results, 17 frameworks and 11 developments in the field of managing occupational, environmental, and toxicological risks associated with engineered nanomaterials were discussed. Various frameworks and tools for identifying, evaluating, and managing the potential risks of engineered nanomaterials vary in terms of their scope, goals, risk assessment approaches, and output, offering diverse applications.

Various tools and frameworks, each with unique properties, applications, and limitations, can assist organizations in achieving their goals related to safety, health, and environmental issues in the field of nanotechnology. Currently, there is no consensus on the optimal approach for assessing the risks of nanomaterials, underscoring the necessity for additional research, development, and collaboration in this field.

Numerous studies have been conducted on the development of modern insulators, including nano-insulators. However, a comprehensive study has yet to be performed to review and investigate the thermal properties of these insulators. Consequently, this study aimed to examine the effect of nanomaterials on thermal insulation function.

In this review, articles were searched for in English databases (PubMed, Web of Science, and ScienceDirect), Persian databases (Magiran, SID), and Google Scholar. The keywords used in the search were Nano Material, Nano Insulation, Thermal Insulation, Thermal Insulator Stability, and Thermal Conductivity in both English and Persian.

Of the 4068 studies identified through search databases, 15 were selected according to the entry criteria. Among the studies, the three types of silicone, composite, and aerogel insulation had the highest frequency (each 26.67%), and SiO2 nanoparticles were the most prevalent nanomaterial (26.67%). According to the studies, the type of nanomaterial used in insulation will improve its properties such as thermal resistance, mechanical strength, dielectric strength, tensile strength, elasticity, and hardness.

The results of this study showed that using nanotechnology could be an effective step in improving the properties of insulation materials, the most important of which is increased thermal resistance. Moreover, nanotechnology insulators can prevent thermal energy loss, reduce costs, and provide safety and comfort.

Nanotechnology is one of the newest, most important and most efficient sciences in the world. It is an interdisciplinary technology that has caused significant changes and developments in the sciences by solving problems and shortcomings. Nanoscience and nanotechnology is the production of nanometer-sized material that has recently attracted the attention of many researchers in the fields of medicine, agriculture and industry. The great importance and application of this technology has attracted much attention. Nanoparticles are particles about 1 to 100 nm the properties of these materials depend on their nanometer size. Nano materials have unique properties including lightweight and small nanoparticles, High surface-to-mass ratio, using in small quantities, saving consumables, being multifunctional and safe for the environment. Chitosan is a linear amino polysaccharide that has been taken into consideration for its properties such as non-toxicity, antibacterial properties, adhesion properties, unique structure, multidimensional properties and high performance. Physical and chemical methods are mostly used to produce nanoparticles. Although these methods may be successful and well-known, they are generally expensive, time-consuming, and dangerous to the environment and humans. Therefore, alternative methods such as microorganisms, fungi, plants, plant extracts and plant biomass should be used instead, which have less environmental hazards. Among the methods of synthesis of chitosan nanoparticles, green synthesis using plant extracts is more beneficial than other methods. Many plant biomolecules such as polyphenols, flavonoids, amino acids, polysaccharides, alkaloids, alcohols, vitamins and proteins can play a role in the formation and stabilization of nanoparticles. The aim of this study was to develop a green method using the extract of the aerial parts of the Russian knapweed to prepare and produce chitosan nanoparticles.

In this study, chitosan nanoparticles were synthesized in a process by the extract of Russian knapweed (Acroptilon repens L.) which containing phenolic compounds. In order to preparation the materials needed for the experiment, the aerial parts of the Russian knapweed in the pre-flowering stage were collected from a land in Ardabil with severe contamination. The collected plant was transferred to the weed laboratory and dried at 60 °C for 72 h in the oven. The dried samples were powdered by a grinding (mill) machine. The aqueous extract was prepared by maceration method. 100, 150 and 200 grams of Russian knapweed powder in to erlenmeyer flask spilled and then added a certain amount of twice distilled water until the final volume reaches of 1000 ml. Then they were placed on the shaker at 25 °C for 24 hours. The obtained extracts were smoothed using Whatman filter paper. At the final stage, the extracts were centrifuged at 5000 rpm for 15 minutes and supernatant were extracted as pure extract and were kept at 4 °C for testing.Chitosan nanoparticles were prepared using ionic gelation method. In the present study, commercial chitosan with medium molecular weight was used. At first, 3 g of chitosan was dissolved in 300 ml of distilled water and placed on a magnetic stirrer at 550 rpm to dissolve completely and evenly at room temperature (with one magnet). To adjust the pH =5, some acetic acid was added. Then a certain amount of Russian knapweed extract was added to it. In the next step, 0.5 g of sodium polyphosphate (TPP) in 50 ml of distilled water was completely dissolved and added drop by drop to the chitosan solution, that was stirring on a magnetic stirrer, and the stirring process continued for 60 minutes. This was repeated for all 3 concentrations of Russian knapweed extract separately. After the reaction time, the final solution was centrifuged for 5 min and after smoothing, the top solution of sediments deposited in the oven was dried for 24 h at 60 °C.

Basic techniques for investigation and determination of nanoparticle properties including: thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) tests. The samples obtained by these tests were analyzed. Infrared spectroscopy was used to investigate the vibrational frequencies of chemical compounds. Thermal weight measurement analysis method, which is based on weight changes during sample heating, was performed to investigate the difference in thermal stability of the samples in the temperature range of 0-700°C. X-ray diffraction pattern of the samples was performed using Cu-Ka radiation. Surface morphology and particle distribution were also obtained using scanning electron microscopy with accelerator voltage k 15. In Spectrophotometric analysis, the presence of a peak in the range of 700 nm indicates the biological synthesis of these nanoparticles with extract of Russian knapweed. FTIR spectroscopy showed the biomolecules present in the extract and involved in the synthesis, which confirms the process of green synthesis of chitosan nanoparticles. In the FTIR spectrum obtained from chitosan nanoparticles with aqueous extract of Russian knapweed and pure extract of Russian knapweed, the presence of factor groups confirming the existence and presence of effective antioxidant compounds such as phenols and flavonoids in the plant extract is used. Based on this, the participation and involvement of phenolic compounds in the Russian knapweed in the synthesis of chitosan nanoparticles is quite clearly observed and understood. The size and morphology of biologically synthesized nanoparticles were determined by scanning electron microscopy, and it was found that the shape of the nanoparticles produced is approximately spherical with an average size of about 33 to 76 nanometers. One of the main reasons for the difference in the shape and size of the synthesized nanoparticles is the different concentrations of the plant extract used. The results of X-ray diffraction analysis also showed the nanocrystals synthesized by the extract of Russian knapweed.

According to the results, it can be said that the polyphenolic compounds in the Russian knapweed extract were acted reducing agents, and also as a complexing agent synthesize chitosan nanoparticles and make them sustainable. The process of ion reduction and synthesis of nanoparticles are done by primary and secondary metabolites such as antioxidants, flavonoids, flavonoids, isoflavones, anticyanidins, isothiocyanates, carotenoids and polyphenols present in the extract. According to the obtained results, plant extracts have a good compatibility with the environment, so that they can be used for rapid production of chitosan nanoparticles, which is a simple, green and efficient method for the synthesis of nanoparticles at room temperature. It is a reducing and inhibiting agent without the use of any chemicals.

Today, nerve cells can be studied using nanotechnology (molecular nanoelectronics). Studies have shown that disturbances in the normal functioning of brain cells can lead to neuropsychiatry attacks. One of the most common diseases (disorders) of the nervous system of the brain is epileptic seizures. In this case, due to electrical discharge of a group of brain neurons, the electrical potential of the brainwave thresholds is higher than normal, which can cause seizures or seizures in the patient. Therefore, the aim of this study was to determine and evaluate theoretically and computationally the use of molecular nanoelectronic technology in the purposeful observation of electrical waves in the brain.

In the present theoretical-computational study conducted at Qom University in 2020, a molecular system for the detection of destructive electrical waves in the brain (waves beyond the threshold of normal brain waves) in patients with epilepsy was discussed. In this regard, several molecular systems such as; Wires, switches, and molecular memory were proposed to monitor electrical waves in the brain. This molecular circuit could be used to predict times close to neuro-cerebral attacks. In this regard, using the quantum theory of density citizenship (at the computational level of DFT-B3LYP / 6-31G), some electronic properties of molecular systems were studied. Gaussian quantum software (G09) was also used to perform the calculations. In this regard, in the absence and the presence of an external electric field, the molecular structure was optimized. Then the electron wave function of the proposed molecular components was investigated. The obtained data here were analyzed using Gaussian (G09) and GaussView(GV5) quantum software.

The results of the present theoretical-computational (non-clinical) study revealed that the design of molecular systems (components) with the ability to respond to brain waves was possible. Calculations indicated that all nanomaterials used in this molecular system could function within the range of brain waves. Therefore, during the occurrence of neuro-cerebral attacks, they can alert the person or those around him by informing him of the occurrence of these attacks.

Based on the results gained from the present study, it possible to design devices and equipment for Nanomedicine (such as warning systems for neurological and heart attacks) payment. In this regard, molecular electronic knowledge can be used, such molecular devices can open new horizons in improving the quality of treatment and life of neurological patients.

Transdermal permeability refers to the delivery of medication to the body through the skin for local or systemic treatment. Transdermal drug delivery systems have not liver first pass effect and gastrointestinal adverse reaction. The use of chemical penetration enhancers and physical absorption systems are obsolete because there are expensive and changes of the skin structure, and the future look at the use of novel drug delivery systems. Nano-carriers is one of the most important new technologies in the field of novel drug delivery. Nanoparticle formulations have about 10 to 100 nanometers. Smaller particles are absorbing more easily than the surface of the skin.

In the present study, a review of previous studies on the use of Nano technology in transdermal drug delivery systems introduced them and their transdermal permeability was paid.

Nanotechnology in different routes and formulations has the ability to increase the permeability of therapeutic drugs depending on their characteristics, the physicochemical characteristics of the drugs, and the therapeutic goals one can choose.

In recent years, the treatment strategy for infectious and autoimmune diseases has significantly changed. Up to now, cancer treatment has been conducted on the basis of clinical and pathological methods. The most common cancer treatments is limited to chemotherapy, radiation therapy and surgery. However, cancer treatment is still not optimal. Common challenges for treatment of certain disease, e.g. cancer, are: systematic and non-specific distribution of drug agents, intolerable toxicity, insufficient drug concentration at the site of treatment and drug resistance.
In recent years, the development and application of nanotechnology has been considered revolutionary in the field of cancer treatment.
This technology offers a unique way to early detection and treatment of cancer. Designing and developing o new drug delivery systems not only increases the drug activity in the target tissue, but also reduces the drug toxicity and leaves it in a controlled manner.
Newcomer vesicles consist of non-ionic surfactants that are biodegradable, non-toxic, stable, and inexpensive and can be used for targeted drug delivery.
 The niosomal vesicles are composed of nonionic surfactants that are biodegradable, non-toxic, stable and lower cost; and it can be used for targeted drug delivery. The major advantages of niosomes can be mentioned: the greater chemical stability, high purity, the availability of various types of non-ionic surfactants, proper storage of drug and cheapness.