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Styrene/methyl methacrylate (St/MMA) copolymer-silica nanocomposite foams were prepared using supercritical C[O.sub.2] as blowing agent, and the relationships between their cellular microstructure and mechanical properties were investigated. The effects of nanosilica content, size, and surface chemistry on the foam's microstructure and properties were examined. Dispersion and distribution of silica nanoparticles with different surface chemistry in St/MMA copolymer nanocomposites were discussed. To determine the most suitable copolymer composition for incorporating silica nanoparticles, some operating conditions such as temperature and pressure were primarily examined to study their effects on the microstructure of resulting foams. In compressive mechanical properties of final foams, a considerably high value was obtained for the compressive strength of the foams of up to 9.5 MPa. The prepared low-density (below 0.2 g/[cm.sup.3]) St/MMA copolymer microcellular foams can be used in green lost foam iron casting processes. Highlights * Styrene/methyl methacrylate copolymer-silica nanocomposite foams were prepared via supercritical C[O.sub.2]. * Foams' cell size was changed by changing silica nanoparticle surface chemistry and size. * The uniform cellular microstructure was achieved by nanosilica size increment. * Increasing nanoparticle size improved the foam's mechanical properties. * Low-density foams were achieved for potential application in lost foam casting. KEYWORDS cellular microstructure, lost foam foundry, mechanical properties, nanosilica, St/MMA copolymer, supercritical C[O.sub.2], 1 | INTRODUCTION Because of the world energy crisis, scientists are very much interested in the development of lightweight and high-mechanical-property materials. (1-4) Producing such materials is viable by the [...]

Diamond nanoparticles/urethane-based bio-adhesives (ND-U-BA) were synthesized via in-situ polymerization. Chemical structure and curing kinetics of the samples were studied by Fourier-transform infrared spectroscopy. Results showed NDs controlled the curing profile of samples. Thermal and crystalline properties were studied using differential scanning calorimetry and X-ray diffraction analyses. Results indicated hard segments had higher ordering levels in the presence of NDs which is due to the lower hydrogen bonding among polyurethane chains. Mechanical results showed ND-U-BA had higher adhesion strength due to the formation of chemical crosslinks and a controlled curing mechanism. MTT and biodegradation studies showed ND-U-BA had acceptable cell viability and degradation content. • Urethane and diamond nanoparticles/urethane-based bio-adhesives were synthesized. • Results showed ND nanoparticles had controlling effect on curing kinetic of samples. • Cell viability of bio-adhesives was improved with the ND nanoparticles' addition. • Incorporation of ND nanoparticles increased the adhesion strength of bio-adhesive. [ABSTRACT FROM AUTHOR]

This research investigated the synthesis of thermoplastic polyurethane (TPU) with a hard segment content (HSC) of 30% weight. The chain extender, the polyols, and the diisocyanate utilized 1,4-butanediol (BDO), and the polycaprolactone diol (PCL-diol) with molecular weights of 2000, 4000, and 10,000 and isophorone diisocyanate (IPDI), respectively. Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (1H-NMR), and X-ray diffraction (XRD) were used to examine the chemical microstructure and physical properties of PCL diol and thermoplastic polyurethanes (TPUs). The molecular weight of the PCL diol as soft segments affected the crystallinity and glass transition temperature (Tg) of TPUs. An increase in PCL diol molecular weight resulted in a reduction in elongation at failure and an increase in ultimate tensile strength. This study was conducted to investigate the permeability and the permselectivity of CO2 and N2 gases over pressure ranges (3 to 9 atm). It was determined that the gas permeability of each sample increased in response to an increase in the pressure of the supplying gas. An elevation in the molecular weight of PCL-diols in TPU samples resulted in a reduction in selectivity and an increase in CO2 and N2 gas permeability. Although IPDI is a non-aromatic cyclic diisocyanate with a significant impact on thermoplastic polyurethane phase morphology, the goal of this paper is to create a change in the molecular weight of PCL-diol and investigate the effect of molecular weight on the resulting morphology as well. [ABSTRACT FROM AUTHOR]

Styrene/methyl methacrylate (St/MMA) copolymer‐silica nanocomposite foams were prepared using supercritical CO2 as blowing agent, and the relationships between their cellular microstructure and mechanical properties were investigated. The effects of nanosilica content, size, and surface chemistry on the foam's microstructure and properties were examined. Dispersion and distribution of silica nanoparticles with different surface chemistry in St/MMA copolymer nanocomposites were discussed. To determine the most suitable copolymer composition for incorporating silica nanoparticles, some operating conditions such as temperature and pressure were primarily examined to study their effects on the microstructure of resulting foams. In compressive mechanical properties of final foams, a considerably high value was obtained for the compressive strength of the foams of up to 9.5 MPa. The prepared low‐density (below 0.2 g/cm3) St/MMA copolymer microcellular foams can be used in green lost foam iron casting processes. Highlights: Styrene/methyl methacrylate copolymer‐silica nanocomposite foams were prepared via supercritical CO2.Foams' cell size was changed by changing silica nanoparticle surface chemistry and size.The uniform cellular microstructure was achieved by nanosilica size increment.Increasing nanoparticle size improved the foam's mechanical properties.Low‐density foams were achieved for potential application in lost foam casting. [ABSTRACT FROM AUTHOR]

Thermoplastic elastomer polyurethanes (TEPUs) were synthesized for orthodontic ligature application and the relationship between various properties and structure of the synthesized TEPUs were studied. Polyethylene glycol and 1,4-butanediol were utilized in various weight ratios as chain extender. Fourier-transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction were used to study the chemical and physical properties and also, tensile, stress relaxation, and elasticity analysis were performed to evaluate the mechanical properties of the prepared samples. Shape memory and stress relaxation analysis with temperature variation showed that the samples could recover the relaxed force due to the shape memory capability. [ABSTRACT FROM AUTHOR]

Background: There are various approaches in primary health care regarding the key role of nurses. This systematic review investigates the roles of nurses, as part of the family medicine team. Materials and Methods: All published articles related to the role of nurses in the family medicine team from January 2000 to March 2022 were the subjects of this study. The eligibility criteria included original articles published in English or Persian in the last two decades. International credible scholarly databases (PubMed, Scopus, Magiran, IranMedex, and SID) were searched using keywords and syntax. Some of the keywords included "Family Health Nurse," "Nurses in Primary Care," "Family Medicine," "Family Physician Care Program," "General Physician Program," "Role," and "Nurse." Data were extracted based on Sample, Phenomenon of Interest, Design, Evaluation, Research type (SPIDER) technique and reported based on the structure of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: Of 147 identified publications by the search strategy, eight eligible empirical studies were included. The results showed that besides providing nursing care, nurses play vital roles in communication and teamwork, assessment, securing health services relevant to communities' needs, education, empowerment, clinical practice, health promotion, prevention, reflective research practice, and counseling. Conclusions: This study identified different roles nurses could play in providing primary health care. These findings are helpful for the replanning or reform of primary health care in countries, which aimed to expand the Family Physician Program (FPP) in their countries, including Iran. [ABSTRACT FROM AUTHOR]

Cross-linked polyvinyl chloride (C-PVC) foams and their nanocomposite foams, containing Cloisite 30B nanoclays were prepared. The effects of compression molding pressure and time on the morphology and mechanical properties of different foams were studied. Increment of molding pressure led to higher apparent density, gel content, cell density, and expansion ratio, and wider cell size distribution, which improved the mechanical properties of the foams. Additionally, with the increasing of molding time, lower cell density and final expansion ratio, narrower cell size distribution, and higher gel content and mechanical properties could be obtained. Moreover, incorporation of Cloisite 30B nanoclay in a PVC matrix not only improved cellular microstructure and mechanical properties but also reduced water uptake ratios of nanocomposite foams. [ABSTRACT FROM AUTHOR]

Thermally and magnetically stimulated shape memory polyurethane (PU) nanocomposites were synthesized for intravascular stent applications. For this end, Fe3O4 magnetic nanoparticles (MNPs) were modified with octadecyl isocyanate (OD) to increase their affinity with the PU matrix by formation of the covalent urea linkages. The results showed that the OD‐grafted MNPs were replaced instead of carbonyl groups of polycaprolactone (PCL) soft segments in hydrogen bond formation with the urethane linkages. This led to higher phase separation degrees among the soft and hard phases, thereby PCL chains could reveal higher crystallization potential. Mechanical studies showed that the nanocomposites had high mechanical strength, Young's modulus, and elongation at break, which improve their practical applications. The nanocomposites showed thermo‐responsive shape memory behavior with a high shape recovery and shape fixity ratios due to the presence of the crystallizable PCL segments. The nanocomposite containing 10 wt% of the OD‐grafted MNPs could recover its original shape (during 90s) in a relatively weak alternating magnetic field (350 kHz and 12.9 kA/m). These results indicated that the prepared nanocomposites could be used to normalize the narrowed blood vessels through the remotely and magnetically‐controllable restricted shape recovery process. [ABSTRACT FROM AUTHOR]

Shape memory polyurethane (SMPU)/graphene quantum dot nanoparticles (GQDs) nanofibers were prepared by electrospinning technique. Results show that the localization of GQD nanoparticles into the nanocomposite electrospun nanofibers has increased the nanofiber average diameter. An increment has been observed in the mechanical strength of nanocomposite nanofiber mats. More uniform and straight nanofibers have been obtained for PU-0.5% due to the relative electrical conductivity induced by the presence of GQD nanoparticles. Presence of crystallizable polycaprolactone (PCL) soft segment in PU structure induced shape memory potential in electrospun scaffolds. In vitro study showed PU-0.5% scaffold had good interaction with 3T3 fibroblast cells. [ABSTRACT FROM AUTHOR]

The goal of this work is to investigate the effect of incorporating organoclays on the cross-link structure, morphology, and thermomechanical properties of cross-linked organoclay/polyvinyl chloride grafted with styrene and maleic anhydride (PVC- g -(St-MA)) copolymer nanocomposites (CPN). Cloisite30B (C30B) and Cloisite15A (C15A) organoclays were used for the preparation of cross-linked PVC- g -(St-MA) nanocomposites by the solution mixing route. The nanoclay content in nanocomposites varied from 0.2 wt% to 1 wt%. The chemical structure and interaction between PVC- g -(St-MA) cross-linked segments and nanoclays were studied by Fourier transform infrared (FTIR) peaks deconvolution method. FTIR spectroscopy suggested the lowest extent of hydrogen bonding interaction for C30B containing sample, which decreased with clay content increment. The morphology of nanocomposites was studied by X-ray diffraction and transmission electron microscopy methods. Morphological observation revealed a near to the exfoliation state for organoclays in PVC- g -(St-MA) nanocomposite containing 1 wt% C30B. However, C15A/PVC- g -(St-MA) nanocomposite (C15A-CPN) exhibited partially intercalated and agglomerated morphology. Differential scanning calorimetry examination was conducted to measure the glass transition temperature (T g) of the segments. At the same clay content, the T g of the C30B containing nanocomposites were higher than that of C15A samples. The mechanical properties of these nanocomposites were also investigated. As a consequence, C30B-CPN showed improved mechanical properties compared to C15A-CPN and cross-linked PVC- g -(St-MA) samples. [ABSTRACT FROM AUTHOR]

Fe3O4 magnetic nanoparticles (MNPs) are subsequently modified with (3‐aminopropyl) triethoxysilane (APTES) and octadecyl isocyanate (OD) to yield MNPs‐g‐OD. Fourier‐transform infrared (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM) verified successful modification of MNPs with three different ratios of OD. Shape memory polyurethane (SMPU) nanocomposites containing 4 wt% of the neat, APTES‐grafted, and OD‐grafted MNPs are prepared through solution casting, where a strong correlation is achieved between the microstructure, crystallinity, thermal, and mechanical properties of the nanocomposites. Phase mixing degree of the soft and hard phases is increased by hydrogen bonding between the OD and polyurethane (PU) chains, causing to decrease of crystallization ability of PU chains. Field‐emission scanning electron microscopy (FE‐SEM) images show that high dispersion of MNPs‐g‐OD reduces the number and size of their aggregation sites in the PU matrix. The nanocomposites show high Young's modulus, because of increasing hydrogen bonding index of carbonyl groups with incorporation of MNPs‐g‐OD into the PU matrix. The nanocomposites show lower Young's modulus with increasing the degree of crystallinity. Shape memory studies indicated that all the samples have considerable shape memory abilities at 50 °C and room temperature. However, shape fixity ratios show a close dependence on the degree of crystallinity at room temperature. [ABSTRACT FROM AUTHOR]

Large quantities of seaweed in marine environments and coastal areas can cause serious hygienic and environmental problems. Anaerobic digestion (AD) could provide a solution and could also be useful for the production of bioenergy and fertilizer. However, the AD of algae biomass has some limitations and further work is required on the process. To increase the efficiency of the process, batches of 350 mL feedstock containing seaweed biomass (Sargassum sp.), inoculum, and different dosages of sludge from drinking water treatment (DWTS) as a micronutrient source to improve biogas production were digested in a 500 mL glass reactor and under mesophilic conditions, leading to significantly enhanced methane production. The highest methane yield (199 NmL g−1VS) was observed when 6 mg L−1 DWTS was added, which showed a 30% improvement compared with the control digester and accounted for a 249.4 kWh increase in net energy per ton. The biodegradability index also increased by 10% compared with the control after the addition of DWTS. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Introduction: This article provides an overview of the Zap - X device, an advanced radiosurgery system used for the treatment of brain tumors and benign brain conditions. The Zap - X device is a non - invasive and painless treatment option that utilizes advanced technology for precise and effective brain radiation therapy with exceptional accuracy and minimal damage to surrounding healthy tissues. With various factors such as low radiation energy, the ability to use a 4 - millimeter collimator, and isocentric planning capability, Zap - X offers an interesting platform for functional radiation therapies. Methods: By utilizing scientific sources and reputable libraries such as PubMed, this article provides a general overview of the Zap - X device, which is a next - generation radiosurgery device for the treatment of brain tumors and benign brain conditions. Results: The Zap - X device utilizes X-ray imaging to visualize the skull structure and tumor location with high precision. Using these images, the device delivers hundreds of radiation beams with sub - millimeter spatial accuracy to the target site in the brain. This notable precision enables healthcare professionals to eradicate tumors or treat benign conditions while minimizing radiation dosage to adjacent healthy tissues. ZAP - X is a "self - shielded" device as almost all radiation remains within the device, eliminating the need for expensive radiation therapy bunkers and regular maintenance, safety measures, and replacement of live radioactive isotopes. Under standard working conditions, the maximum expected equivalent dose rate at a distance of 1 meter from the device is less than 1 mSv/year, which corresponds to the limit for public exposure. A typical radiosurgery treatment with Zap - X takes approximately 30 minutes, and the radiation dose administered is equivalent to what is typically given over the course of a month through conventional radiation therapy. The inherent risk of an incorrect treatment is delivering dangerous doses to the brainstem, which can have serious potential neurological consequences. Conclusions: The Zap - X device fulfills safety requirements, precision, and performance widely accepted in the field of radiation oncology and radiosurgical surgery and features advanced characteristics such as image - guided systems, beam delivery design, and precise radiation targeting and control. It is an advanced and powerful radiosurgery solution in the field of neurosurgery and provides a highly accurate and effective treatment approach for patients with brain tumors and benign brain conditions. [ABSTRACT FROM AUTHOR]

Background: Drowning is the third leading cause of death due to unintentional injuries worldwide and accounts for 7% of all injury-related deaths. The aim of this study was to investigate the trend of deaths due to drowning in the provinces of Iran from 2017 to 2020. Methods: This is a descriptive study in which the data on deaths due to drowning during 2017-2020 were extracted from the Death Registration System of the Ministry of Health and Medical Education (using the W65-W74 code based on the International Classification of Diseases ICD-10). We used population data from the population and housing census (2016) and population estimates for the years after the census, which were prepared and published by the Statistics Center of Iran. Results: According to the reports, 862, 853, 1126, and 1028 deaths due to drowning were registered in the Death Registration System of the Ministry of Health and Medical Education in 2017, 2018, 2019, and 2020, respectively. In all these years, 82% of deaths occurred in men. During these four years, 92-93% of these deaths occurred among Iranians, and 53-57% of them were in urban areas. The proportion of deaths according to age groups was 10% in less than 5-year-old children, 22-27% in the 5- to 17-year-old, and 24-29% in the 18- to 29-year-old ones. Death due to drowning ranked third in the age group of 5-14 years in 2019 and 2020 and fourth in the age group of 1-4 years in 2018 and 2020. In 2017, the highest rate of deaths (per 100000 population) due to drowning belonged to Khuzestan province (2.63). In 2018 and 2019, Bushehr province (2.91-3.19), and in 2020 Hormozgan province (3.20) had the highest number of deaths due to drowning. Conclusion: Depending on the different circumstances, at-risk population groups, and geographical conditions, provincial authorities should plan on preventing deaths and complications due to drowning. [ABSTRACT FROM AUTHOR]

Background: The Isfahan COVID Cohort (ICC) study was designed to investigate the short- and long-term consequences of patients with COVID-19 in Iran. This report presents the rationale, methodology, and initial results of ICC. Materials and Methods: ICC is a 5-year multicentric prospective cohort study that is ongoing on two groups including 5000 patients hospitalized with moderate or severe and 800 nonhospitalized patients with mild or asymptomatic COVID-19 in Isfahan. The ICC endpoints are morbidity, mortality, incident cases, or worsening of underlying noncommunicable diseases (NCDs) and their risk factors. In the current analysis, we examined the persistent symptoms and incident NCDs or risk factors in 819 previously hospitalized patients who completed 1-year follow-up. Results: The two most common symptoms were joint pain/myalgia (19.7%) and dry cough/dyspnea (18.7%). Around 60% of patients had at least one symptom which was more common among women than men and in middle aged than younger or older patients. Female (odds ratio [OR] =1.88, 95% confidence interval [CI]: 1.39–2.55) and highly-educated patients (OR = 2.18, 95% CI: 1.56–3.04) had higher risk of having any symptom in 1-year follow-up. New cases of hypertension followed by diabetes then coronary heart disease (CHD) were the most common incident NCDs. Conclusion: During 1-year follow-up after hospital discharge, about 60% of patients experienced persistent symptoms. Incident hypertension, diabetes, and CHD were the most common events seen. Close monitoring and extensive health services with integrative approaches are needed to improve the health status of these patients. [ABSTRACT FROM AUTHOR]

Introduction. We intended to explore the prevalence of chronic kidney disease (CKD) and its different stages, as well as CKD associated variables in the adult population in Isfahan province, Iran. Methods. Adults aged ≥ 18 were recruited in a cross-sectional study from 2017 to 2019. Data including demographics, anthropometrics, and laboratory findings were collected from each subject. The equation of chronic kidney disease-Epidemiology Collaboration (CKD-EPI) was used to estimate glomerular filtration rate (eGFR), and eGFR and UACR values were utilized to determine the stages of CKD. Results. Data from a total of 3374 subjects was analyzed. The mean age of participants was 49.3 ± 14.09 years and 59.3% were female. The prevalence of CKD was 18.5%. Only 0.25 and 3.5% of the population were in CKD stage 3 and 4, while most of the patients were in CKD stage 2 (7.6%) and stage 1 (7.1%). CKD patients were mostly on refined grains diet and used lesser dairy products compared to healthy participants. Variables including systolic blood pressure (OR = 1.018; P < .001), diastolic blood pressure (OR = 1.005; P < .05), fasting blood sugar (OR = 1.011; P < .001), female sex (OR = 1.319; P < .05), body mass index (OR = 1.030; P < .05), married status (OR = 1.335; P < .05), and smoking (OR = 1.529; P < .05) were significantly associated with increased risk of CKD in the logistic regression analysis. Conclusion. According to our results, the prevalence of CKD, especially stages 1 and 2, is quite high in central part of Iran. These findings help us to improve the screening for CKD patients and perform larger scale studies to identify the challenges ahead. [ABSTRACT FROM AUTHOR]

Switchable wettability potential in smart fibers is of paramount importance in various applications. Light-induced controllable changes in surface wettability have a significant role in this area. Herein, smart waterborne homopolymer, functional copolymer with different polarity and flexibility, and multi-functional terpolymer particles containing a time-dependent dual-responsive acrylated spiropyran, as a polymerizable monomer, were successfully synthesized through eco-friendly single-step emulsifier-free emulsion polymerization. Presence of 10 wt% of butyl acrylate and dimethylaminoethyl methacrylate relative to methylmethacrylate as functional comonomers decreased the T g of the samples almost 20 ℃ and increased their polarity. The optical properties of the particles were investigated, and the UV-vis and fluorescence spectroscopy results showed that not only polarity and flexibility of the polymer chains may have a positive effect on improving the optical properties, but also the simultaneous presence of functional groups has a synergistic effect. The smart polymer particles with flexibility and polarity features exhibited higher absorption and emission compared to other samples. Inspired by these findings, multi-functional smart polymer fibers were prepared using the electrospinning method. The smart multi-functional electrospun fibers containing few-layer Ti 3 C 2 MXenes were synthesized to improve the fibers' properties and change the surface wettability due to the hydrophilic functional groups of MXene. Field-emission scanning electron microscopy images displayed the successful preparation of few-layer MXenes. Smooth and bead-free fibers with bright red fluorescence emission under UV irradiation were shown using fluorescence microscopy. The study on the surface wettability of fibers revealed that UV and visible light irradiation induced reversible time-dependent changes in the wettability of the smart multi-functional MXene/polymer electrospun fibers from hydrophobic to hydrophilic, reaching a water contact angle of 10° from an initial water contact angle of 100° under UV light and also changing to superhydrophilic state with passing time. Upon visible light exposure, the fibers returned to their original state. Furthermore, the fibers demonstrated a high stability over five alternating cycles of UV and visible light irradiation. This study shows that the fabrication of time-dependent smart fibers, utilizing the flexibility and polarity in the presence of MXenes, significantly improves and controls surface wettability changes. The outstanding dynamically photo-switchable wettability of these fibers may offer exciting opportunities in various applications, especially in the separation of oil from water contaminants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Iran has implemented the Family Physician Program (FPP) in 2005 in 4 provinces. This program was supposed to be expanded across the country; however, it faced various challenges. Considering the impact of the referral system on the quality of the FPP implementation, different studies were conducted to evaluate the performance of this system. Therefore, this systematic review of the literature was conducted to investigate the challenges of the referral system of the FPP in Iran., Methods: All published original articles, reviews, or case studies published in English or Persian related to the challenges in the referral system FPP in Iran from 2011 to September 2022 were included in this study. International credible scholarly databases were searched. The search strategy was defined based on keywords and the search syntax., Results: Out of 3910 articles identified by the search strategy, considering the inclusion and exclusion criteria and relevance of the study, and accreditation of the studies, 20 studies were included. The referral system suffers from different challenges in the areas associated with policy and planning, management, referral process, and health service recipients., Conclusion: The inefficient gatekeeping role of family physicians was one of the most important challenges of the referral system. The referral system should be improved by having evidence-based guidelines and policy documents, unified stewardship, integrated insurance schemes, and effective communication between different levels of care., Competing Interests: The authors declare that they have no competing interests., (© 2023 Iran University of Medical Sciences.)