Impaired wound healing affects hundreds of million people around the world; therefore, chronic wounds are a major problem not only for the patient, but also for already overloaded healthcare systems. Chronic wounds are always very susceptible to infections. Billions of dollars are spent to discover new antibiotics as quickly as possible; however, bacterial resistance against antibiotics is rising even faster. For this reason, a complete shift of the antibacterial treatment paradigm is necessary. The development of technology has allowed us to rediscover well-known agents presenting antimicrobial properties with a better outcome. In this context, silver nanoparticles are a promising candidate for use in such therapy. Silver has many useful properties that can be used in the treatment of chronic wounds, such as anti-bacterial, anti-inflammatory, and anti-oxidative properties. In the form of nanoparticles, silver agents can work even more effectively and can be more easily incorporated into various dressings. Silver-based dressings are already commercially available; however, innovative combinations are still being discovered and very promising results have been described. In this review article, the authors focused on describing experimental and clinical studies exploring dressings containing either silver or silver nanoparticles, the results of which have been published in recent years.

The skin, acting as the outer protection of the human body, is most vulnerable to injury. Wound healing can often be impaired, leading to chronic, hard-to-heal wounds. For this reason, searching for the most effective dressings that can significantly enhance the wound healing process is necessary. In this regard, silk fibroin, a protein derived from silk fibres that has excellent properties, is noteworthy. Silk fibroin is highly biocompatible and biodegradable. It can easily make various dressings, which can be loaded with additional substances to improve healing. Dressings based on silk fibroin have anti-inflammatory, pro-angiogenic properties and significantly accelerate skin wound healing, even compared to commercially available wound dressings. Animal studies confirm the beneficial influence of silk fibroin in wound healing. Clinical research focusing on fibroin dressings is also promising. These properties make silk fibroin a remarkable natural material for creating innovative, simple, and effective dressings for skin wound healing. In this review, we summarise the application of silk fibroin biomaterials as wound dressings in full-thickness, burn, and diabetic wounds in preclinical and clinical settings.

INTROduCTIONThe prevalence of aortic valve stenosis (AS), the most common acquired valvular heart disease, increases with age. As life expectancy is increasing, the number of patients requiring treatment for AS is expected to grow steadily. 1,2 Advanced age is a known risk factor in surgical aortic valve replacement (SAVR). Introduction of transcatheter aortic valve implantation (TAVI) provided an effective and less -invasive alternative

We propose a modification of the Shack-Hartmann wavefront sensor in which the lens array is made of Fresnel zone plates. The modification allows students to construct the sensor in an undergraduate laboratory at little cost. In spite of its simplicity the sensor has a sensitivity of / 50 in relative measurements, which is sufficient to measure a wavefront of a laser beam distorted by various optical elements as well as by a turbulent airflow. Such an experiment is an excellent supplement to a course in optics, gives students a deeper understanding of the wavefront concept, and demonstrates the wavefront measurement technique widely used in physics, astronomy, and medicine.

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