The exceptional tunability of chemical, mechanical, and shape memory properties of segmented thermoplastic polyurethanes (STPUs) makes them promising materials in a wide range of biomedical applications. STPUbased shape memory polymers (SMPs) that stably maintain their chemical, thermomechanical, and shape memory properties even after implantation could provide a reliable platform for controlled environmental response. For example, materials could be actuated at set time points to deliver bioactive agents, or cleavable compounds could be incorporated into a stable SMP that responds to wound signals for use in diagnosis. To this end, a library of STPUs with varying ratios of hard to soft segments was synthesized and characterized. It was found that using polypropylene glycol as the soft segment and triethylene glycol as the chain extender with hexamethylene diisocyanate induced sufficient phase separation in STPUs to provide a shape memory system. The polymers had more than 90% shape recovery ability and high enough transition temperatures (56−58 °C under dry and 44−51 °C under wet conditions) to enable maintenance of their temporary shape at body temperature. We tuned chemical, mechanical, thermal, and shape memory properties by changing the composition and characterized their stability in degradation media (more than 94% mass remaining at 40 days under accelerated conditions for polymers with higher hard segment ratios). The cytocompatible STPUs were highly stable (>90%) in their primary and secondary geometries in in vitro degradation media, indicating that they would stay intact after implantation. Then, the materials were actuated by heating at userdefined time points, upon which they returned to their primary shapes. As a proof of concept, we incorporated magnetic nanoparticles into this system to provide a magnetically actuated SMP that induced 44% shape recovery only after 5 min of exposure to a magnetic field. This system provides a platform for future generations of STPUs that include other cleavable or environmentally responsive components so that wound or clinician-controlled signals can act as external stimuli to cause shape and morphological changes.

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BackgroundTrauma, in addition to mortality and disability experienced by an individual, imposes direct and indirect economic and social costs on a community. Traditionally, trauma is a disease of young and middle age adults, an age group which is known to be the most dynamic and economically productive of the community. Increasing our knowledge concerning the etiology and patterns of trauma seems to be the most profitable and accessible way to prevent injuries of this nature.ObjectivesThis study was designed to evaluate the epidemiology of adult trauma in Kashan, Iran.Patients and MethodsThe current study used a retrospective cross-sectional approach, enrolling all trauma adults (20 - 60 y) admitted to the Shahid Beheshti Hospital, Kashan, between 2007 and 2011. Age, gender, place of residence, work status, educational level, urban/rural location of the accident, method of transportation to hospital, injured body areas of the victims and therapeutic interventions, were extracted from the data registry and analyzed through descriptive statistics using SPSS software.ResultsA total of 22 564 patients were included in this study. Mean age of the victims was 33.18 ± 10.90 years and the male/female ratio was 4:1. Most of the victims were manual workers (61%), and they had completed primary and junior high school level education (49.4%), they were also more likely to be residents of urban areas (88.6%). Regarding the place of injury, most accidents occurred on city streets (43.8%). Approximately 40% of the total victims were transferred to the hospital by emergency medical services (EMS). During the study period, 260 deaths were recorded and among these, 76% were related to traffic accidents.ConclusionsRegarding the high prevalence of trauma found in manual workers with low educational levels and motorbike users, the establishment of an integrated program aimed at improving public knowledge on the use of safety and protective measures in work environments should be implemented. The use of safety protective equipment by cyclists, motorbikers and car passengers should also be enforced.

Introduction: Working in healthcare jobs and the health sector, where one has to face human communication and health-related issues every day, can cause a lot of stress. Nurses are important members of the healthcare system of a country; they play a crucial role in improving the quality of healthcare. Burnout as the main characteristic of job stress refers to a delayed reaction to chronic stressors at work. Objective: The aim of this study was to determine the relationship between burnout dimensions and psychological symptoms (depression, anxiety and stress) among nurses. Material and Methods: This present study was a descriptive-analytic and cross-sectional study, which was conducted on 270 nurses working in educational hospitals in Rasht (Iran), using stratified random sampling. The research instruments included demographic questionnaire, Maslach burnout inventory and depression, anxiety and stress questionnaire {Depresion Anxiety, Stress, Scale (DASS21)}. Data was analyzed using descriptive and inferential statistics (Pearson correlation and regression). Results: The findings showed that there is a significantly positive correlation between burnout dimensions (emotional exhaustion, depersonalization and reduced personal accomplishment) and psychological symptoms (depression, anxiety and stress) in nurses (P<0.001). Burnout also significantly predicted 42%, 25% and 32% of variance in nurses' depression, anxiety and stress respectively (P<0.001). Conclusion: Considering the fact that mental health can positively affect the nursing profession and given the positive relationship between burnout dimensions and psychological symptoms, it is recommended that we must the reduce burnout rate by holding emotion regulation-training classes and promote it.

Chronic wound healing is often negatively impacted by infection. Efficient infection assessment is crucial for effective treatment, and biofilm inhibition could improve treatment efficacy. To that end, we developed a bacterial protease‐responsive shape memory polymer based on a segmented polyurethane with incorporated poly(glutamic acid) peptide (PU‐Pep). Poly(glutamic acid) degrades in response to bacterial proteases to trigger shape recovery of PU‐Pep films that are programmed into a secondary shape. These materials have transition temperatures well above body temperature (~60°C), which enables stable storage in temporary shapes after implantation. Synthesized polymers have high shape fixity (~74%–88%), shape recovery (~93%–95%), and cytocompatibility (~100%). Strained PU‐Pep samples underwent shape recovery within ≤24 h in response to the V8 enzyme from Staphylococcus aureus (S. aureus, ~50% recovery) and multiple bacteria strains (S. aureus [~40%], Staphylococcus epidermidis [~30%], and Escherichia coli [~25%]), and they had minimal shape change in response to media controls and mammalian cells. Shape recovery of strained PU‐Pep samples prevented biofilm formation on the sample surfaces, and resulting attached planktonic bacteria were vulnerable to applied treatments. PU‐Pep with physically incorporated antimicrobials simultaneously prevented biofilm formation and killed isolated bacteria. PU‐Pep dressings displayed visible shape change and resistance to biofilm formation in in vitro and ex vivo models. In the in vitro model, PU‐Pep shape change also disrupted pre‐formed biofilm structures. This novel bacterial protease‐responsive biomaterial could serve as a wound dressing that changes shape specifically during bacterial colonization to alert clinicians to infection and make biofilm‐associated infections easier to treat.

Repeated use of intravenous infusions to deliver drugs can cause nerve damage, pain, and infection. There is an unmet need for a drug delivery method that administers drugs on demand for prolonged use. Here, we developed magnetically responsive shape memory polymers (SMPs) to enhance control over drug release. Iron oxide magnetic nanoparticles (mnps) were synthesized and incorporated into previously developed SMPs to enable magnetically induced shape memory effects that can be activated remotely via the application of an alternating magnetic field. These materials were tested for their shape memory properties (dynamic mechanical analysis), cytocompatibility (3T3 fibroblast viability), and tunable drug delivery rates (UV–VIS to evaluate the release of incorporated doxorubicin, 6-mercaptopurine, and/or rhodamine). All polymer composites had >75% cytocompatibility over 72 h. Altering the polymer chemistry and mnp content provided methods to tune drug release. Namely, linear polymers with higher mnp content had faster drug release. Highly cross-linked polymer networks with lower mnp content slowed drug release. Shape memory properties and polymer/drug interactions provided additional variables to tune drug delivery rates. Polymers that were fixed in a strained secondary shape had a slower release rate compared with unstrained polymers, and hydrophobic drugs were released more slowly than hydrophilic drugs. Using these design principles, a single material with gradient chemistry and dual drug loading was synthesized, which provided a unique mechanism to deliver two drugs from a single scaffold with distinct delivery profiles. This system could be employed in future work to provide controlled release of selected drug combinations with enhanced control over release as compared with previous approaches.

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This work presents the study of morphology, melting and crystallization characteristics, and mechanical properties of the PA‐6/SAN blends reinforced with multiwalled carbon nanotubes (MWCNTs). The Taguchi method was employed to design the experiments based on the three varying parameters (ie, blend composition, nanofiller content, and sequence of blending) to obtain the optimized mechanical properties of the nanocomposites. In addition, localization of nanotubes was studied in terms of thermodynamic and kinetic prospects. It was observed that, due to the preferential tendency for localization of the carbon nanotubes toward the PA‐6 matrix, mixing protocol had an important role in determining the performance of the nanocomposites. Incorporation of an optimum weight percent of the MWCNT provided a good dispersion of the nanotubes and also an appropriate morphology for the blend. According to the analysis based on the Taguchi method, the optimum mixing protocol, blend composition, and MWCNT loading were M2, 80/20, and 0.5 wt%, respectively.