جستجوی مقالات مرتبط با کلیدواژه « نفوذ » در نشریات گروه « پزشکی »

Magnesium alloy-based bioabsorbable cardiac stents have shown broad prospectives for the replacement of current scaffolds, but for complete use and replacement, it is necessary to determine the interaction between the magnesium alloy substrate and the drug loading system. The purpose of this study was to understand the effect of stents made of magnesium alloy on the speed and amount of drug release from it.

In this study, Everolimus was loaded on poly-L-lactic acid and coated as a nano-hybrid coating on a sample of magnesium alloy and cobalt-chromium alloy to investigate release in the simulated body fluid system. Also, the effect of pH and released hydrogen on drug release, corrosion and mass reduction of the sample with magnesium alloy base was measured and the efficiency of the drug-carrying polymer coating in reducing the corrosion rate of magnesium alloy sample was evaluated. For this purpose, UV / VIS spectrophotometer, hydrogen measurement system and scanning electron microscope were used.

The drug diffusion coefficient for magnesium base sample was calculated 6.06×10-10 and for sample with cobalt-chromium base was calculated 3.64×10-11 during the period of 50-100 days from the beginning of release, which was due to the production of hydrogen and corrosion products in magnesium stents. It was also found that the polylactic acid coating, is a good drug carrier and also it reduces the corrosion rate of magnesium stents. In addition, pH changes do not have much effect on drug release.

Magnesium stents have more drug release than conventional stents and are more capable to preventing re-stenosis.

Objective People with disabilities are more likely to experience poorer health status, compared to the general population; however, their health issues do not receive enough attention from policymakers. This article aimed to identify the factors that hinder the health problems of people with disabilities to be on the national agenda in Iran. Materials & Methods This phenomenological qualitative research was conducted in Tehran City, Iran, from September 2015 to March 2017. We conducted 22 quasi-structured face to face interviews with relevant policymakers at the national level. Snowball sampling method was applied to identify the interviewees. The interviewees were well-informed and had long and valuable experiences in the field of policymaking for people with disabilities. The policymakers from a verity of public organizations, ministries, non-governmental organizations, Islamic Consultative Assembly, Tehran municipality and the health insurance organizations participated in the study. We used an interview guide in data collection process which covered the main study questions. On average, the interviews lasted about 30 minutes to 1.5 hours. The validity of the study was assessed through member checking. Thematic analysis was performed in three steps to identify the main concepts of the study. In open coding, identifying, naming and describing phenomena in the text were performed. Following open coding, codes were grouped into several subcategories. Then, the main concept of the study was created by formulating a general description of generated subcategories. We used MAXQDA to analyze the obtained data.  Results We found three main categories and 13 subcategories. In the influence category, three subcategories were created; low influence in the policy process, the lack of structural independence, the inferiority of associations and nongovernmental organizations’ positions for policymakers and the low ability in lobbying and networking. In the minority category, we found 6 subcategories consisting of more attention to public health issues by policymakers, neglect of the specific needs of minority groups by health policymakers, policymakers’ unattractiveness in the health problems of people with disabilities, the lack of significant financial and political benefits for policymakers, the lack of awareness about the health issues of people with disabilities, and the inferiority of disability issues for policymakers. In the category of lack of integrated voice, three subcategories were created, including a lack of integration among people with disabilities, inattention to personal and group interests and the lack of coherent communication networks.  Conclusion To meet their requirements, it is essential to enhance the influence of people with disabilities, associations and the welfare organization in the policymaking process. This can be achieved by increasing the interaction of significant individuals in the disability area with other key policymakers in other sectors. Running campaigns, engaging with celebrities as well as experienced and influential managers, and the systematic use of media and social networks may improve policymakers' attention to prioritizing health issues of people with disabilities.

Dust is one of the harmful factors in some working environments. One of the way to reduce exposure to dust in these environments is to use air purifying masks. Therefore, the purpose of this study was Performance evaluation of respiratory masks used by refractory workers in controlling exposure against particulate pollutants in a steel factory.
The performance of three types of masks against particle contamination was evaluated in this study. To evaluate performance, during the work and simultaneously the concentration of particles in inside and outside of the mask was measured then the percentage of efficiency and percentage of penetration rate was calculated.
Findings: The average of penetration rate percentage in the FFP3 mask was higher than FFP2 and elastomeric halfmask with a P100 filter. Performance evaluation of FFP2 and FFP3 masks based on of consumption time showed that during the first few hours of consumption efficiency decreased and then increased.
Resistance surface of filter and air penetration from free space between face and around the mask is the main factor of poor performance masks.

All revolutions occurred for ages have undergone two hard phases which has special importance. One is the occurrence of the revolution and the other is the constancy and continuity of the revolution, so as to achieve its goals. Sustaining and maintaining revolution is more arduous and difficult task between the two mentioned principals.The Islamic Republic revolution of Iran is not an exception and like the other revolutions has to use all its capacity for continuing, maintaining, and achieving its ideals.
Therefore, this study aimed to state the important indicators of people of the revolution in line with the principal of impenetrability and to introduce people of the revolutionby specifying these indicators with respect to the driving forces of the revolution. People of the revolution ought to collect both piety and impressing indicators as community properties. Further,they have to collect revolutionary morale and intuition indicators, and they need to avoid factors and bases of existing from the circle of revolutionary people.
So, we try to identify and introduce some kind of opportunity and threat present in the Islamic society by introducing the personality of the revolutionary people. These threats sometimes may appear among these seemingly revolutionary people.
Since Imam Ali’s government has invaluable lessons similar to our revolution, we are going to specify signs and symptoms which a revolutionary person must have from Imam Ali’s perspective in Nahjulbalagheh, because some people may be both pious and from community properties but they may not be revolutionary people.

Dermal exposure to chemical agents can result in a variety of occupational diseases and disorders, including occupational skin diseases and systemic toxicity. T he present paper focused on transport properties of nanocomposite based on carboxylated nitrile butadiene rubber (XNBR)-nanoclay. In this study, XNBR gloves nanocomposite were prepared at different amounts of nanoclay; i.e. 3, 6, 9 phr (parts per hundred of rubber). Swelling procedure was conducted for different nanocomposites using two neat organic solvents (i.e. Carbon tetrachloride (CCl4) and Ethyl acetate). Near Fickian diffusion was observed for XNBR based nanocomposites containing different amounts of nanoclay. The permeability coefficients were higher for ethyl acetate compared to CCl4 in all XNBR nanocomposites. In addition, a significant decrease was observed in the permeability coefficients of the selected solvent XNBR3. Analysis of transport properties of synthesized nanocomposites illustrated that application of these materials seems promising for manufacturing protective gloves.

Personal protective equipments (PPE) are common equipments for control of workers exposure to harmful agents in work environment. Regarding to the critical role of the filter collection efficiency under hazardous conditions such as exposure to carcinogen materials, this study was performed to determine the effect of different factors on efficiency of respirator filters in removing hexavalent chromium mist. In this quasi-experimental study, homogenous chromium mist at different conditions (concentration 1.25 and 2.5 mg/m3, relative humidity 50 and 80%, and temperature 0-5 and 35-40 oC) passed through two types of respirator filters (MSA and Spasciani). All samples (n= 384) were collected, using NIOSH 7600 test method at upstream and downstream of respiratory filters, simultaneously and analyzed, using an atomic absorption spectrometer and inductively coupled plasma (ICP), respectively. Although type of filter had significant effect on hexavalent chromium mist removal, the ANOVA test results indicated that the increase of chromium mist concentration and relative humidity resulted a significant decrease in removal efficacy 0.53% and 0.42%, respectively (p<0.001). The temperature had not significant effect on filter efficiency. Increase of hexavalent chromium mist concentrations and relative humidity has significant negative effect on collection efficiency of respirator filters.