The short story of the miraculous daily resurrection of life in us

The development of modern science in various fields today often exceeds the limits and ideas of the bravest philosophers and scientists of our time. And certainly the most intriguing areas of research are those based on the molecular basis of life processes. The complexity and complexity of the human body, countless intertwined feedback loops that regulate internal processes in the body and enable its survival, can best be interpreted at the micro and nano level, ie at the level of the cell and its subcellular structures. This opens up huge potentials for understanding and influencing living systems, but also unlimited challenges for science. The monograph "How cells live and die in us" is unique in many ways. The multidisciplinary procedure provides a comprehensive overview of the complexity of the human body, as well as its possible functioning at the cellular micro and nano level, ie at the level of molecules, atoms, nuclei, protons, etc. The story is inspired by Balasevic's line between the year of birth and the year of death

Controversies related to real protection against SARS-CoV-2 virus of the most frequently used face masks

Face masks serve to protect the respiratory system from unwanted aerosol droplets, in which various types of pathogens or pollutants are present. They are particularly important during a pandemic, like SARS-CoV-2 pandemic we are withessing. The efficiency of filtration of aerosol droplets, which contain the virus particles, is generally unsatisfactory, especially in conditions of extremely virulent environments, for the most of commercially available masks. Therefore, the challenge is to produce masks with increased filtration efficiency, in order to reduce the percentage of virus penetration through the mask. Hence, it is crucial to correctly define the possibilities and limitations of today's most commonly used epidemiological masks, in order to successfully define completely new concepts of face masks manufacturing, which would enable the most effective protection not only of medical workers but also patients, especially in areas where virus concentrations are extremely high. Also, it has been shown that, in addition to the concentrations of infectious pathogens in a given environment, the conditions in which infection with a given pathogen occurs, such as temperature and humidity within a given contaminated space, are also important

Nucleation of biomimetic hydroxyapatite

Introduction. The aim of the study was to assess the formation of biomimetic calcium hydroxyapatite (HAP) on the surface of different substrates. Material and Methods. Silica coated stainless steel tapes and thin polymer films (alginate, cellulose, poly lactide-co-glycolide - PLGA) deposited on hydroxyapatite scaffold were used as substrate. Supersaturated simulated body fluid (SBF) and SBF combined with Fetal Calf Serum (FCS) or Eagle’s Minimum Essential Medium (EMEM) were used as bioactive liquid medium where biomimetic nucleation of HAP occurred. Infrared spectroscopy with Fourier transformation was used to analyze the formed phases, while scanning electron microscopy indicated the morphology of nucleated phase. Results. The results of measuring the mass with volume adjustments done by the BET method showed that the thickness of the film of nucleated calcium hydroxyapatite depended on the time that samples spent soaked in SBF-in as well as the type of selected biomimetic medium. Conclusion. Biomimetic calcium hydroxyapatite is possible to produce by self nucleation on different substrates in the presence of simulating body fluid

Hemizmi umrežavanja i biološke funkcije različitih vrsta fosfatnog cementa

This article provides an overview of calcium phosphate systems used in different formulations of cement mixtures. Chemism of reactions that occur in contact of these systems with water medium shows diversity and specificity of each of selected types of mixtures. As it can be clearly seen from reactions that occur between components of cement mixtures, highly active calcium deficient hydroxyapatite is always an end product in all reactions. This makes these systems extremely biocompatible and suitable for use in dentistry from the standpoint of chemical and biological degradability.U radu je dat pregled kalcijum-fosfatnih sistema koji se koriste u različitim formulacijama cementnih mešavina. Hemizmi reakcija koje se javljaju pri kontaktu takvih sistema s vodenom sredinom pokazuju raznovrsnost i specifičnost svake izabrane mešavine. Kao što se jasno vidi iz reakcija koje se odigravaju između komponenata cementnih mešavina, uvek se kao krajnji proizvod u svim reakcijama pojavljuje visokoaktivni hidroksiapatit s nedostatkom kalcijuma. To čini ove sisteme izuzetno biokompatibilnim i, sa stanovišta hemijske i biološke degradibilnosti, pogodnim za primenu u stomatologiji

Detailed characterization of the Ti-O based thin films obtained by cathodic arc evaporation

Physicochemical properties of thin films on the base of titanium oxides, obtained by a cathodic arc evaporation on the surface of glass substrate are analysed in details. The analysis of these films was made by using XRD, FTIR, SEM, XPS analysis and ellipsometry. On the basis of these analyses, particularly analysis obtained by XPS, the oxidative state Ti and corresponding phases are determined through various film layers from the surface to the substrate. The depth of the various levels and their extinction coefficients and refractory indexes are estimated by ellipsometry

Primena vrlo aktivne kalcijum-silikatne faze u endodonciji

Introduction. Mineral trioxide aggregate (MTA) is one of the most commonly used materials in endodontics. Given its shortcomings, there is an intensive search for new materials. Calcium-silicate phase (CS phase) is a new material synthesized by the method based on a combination of sol-gel process and self-propagation synthesis which can significantly improve setting time through accelerated hydration. The aim of this study was to explain the mechanisms of hardening of CS phase in aqueous medium as similar mechanism is expected in contact with body fluids. Materials and Methods. CS phases Ca3SiO5 (C3S) and 2β-CaSiO4 (β-C2S) were synthesized from CaCl2·5H2O (Merck, Germany). To investigate the process of hydration, CS were mixed with water and kept at 37 °C for 28 days in closed polyethylene containers. Analysis of the composition of samples before and after immersion in water for 1, 3, 7 and 28 days was performed using X - ray diffractometry and IR. Results. XRD patterns for hydrated samples during 1, 3, 7 and 28 days showed that the amount of hydrated tobermorite phases relative to the amount of CS phase changes with the time of hydration. After 1 day, in addition to the hydrated phases, a significant amount of untransformed β-C2S and C3S were found while after 28 days hydrated CS phase was completely transformed to tobermorite with a small amount of portlandite. Conclusion. Using combined method of sol-gel and self-propagating waves at high temperature very active nanostructured silicate phases were obtained. Hydration process of CS phases was analyzed using XRD and FTIR, the mechanism of hydration was proposed and it was pointed to the difficulties in determining the exact reaction as well as the problem of determining the exact structure of tobermorite.Uvod. Mineral trioksidni agregat (MTA) je jedan od najčešće korišćenih materijala u endodonciji. S obzirom na njegove nedostatke, intenzivno se traga za novim materijalima. Kalcijum-silikatna faza (CS faza) je novi materijal sintetisan prema metodi zasnovanoj na kombinaciji sol-gel procesa i samoprenosivoj sintezi koja može značajno poboljšati vreme vezivanja kroz ubrzanu hidrataciju. Cilj ove studije je bio da objasni mehanizme otvrdnjavanja CS faze u vodenom medijumu budući da se sličan mehanizam očekuje u kontaktu s telesnim tečnostima. Materijal i metode rada. CS faze Ca3SiO5 (C3S) i 2β-CaSiO4 (β-C2S) su sintetisane iz CaCl2·5H2O (Merck, Nemačka). Da bismo istražili proces hidratacije, CS su pomešani s vodom i ostavljeni 28 dana na 37°C u zatvorenim polietilenskim kontejnerima. Analiza sastava uzoraka pre potapanja u vodu i jedan dan, tri, sedam i 28 dana nakon potapanja izvršena je difraktometrijom radioloških zraka i FTIR. Rezultati. XRD obrasci za uzorke hidratisane tokom jednog, tri, sedam i 28 dana pokazuju da se količina hidratisane faze tobermorita u odnosu na količinu faze CS menja s vremenom hidratacije. Kod uzorka hidratisanog jedan dan, pored hidratisane faze tobermorita, utvrđene su i značajne količine β-C2S i C3S koje su ostale netransformisane, da bi kod uzoraka hidratisanih 28 dana CS faza bila potpuno transformisana u tobermorit uz male količine portlandita. Zaključak. Pomoću kombinovane metode sol-gel i metode samopropagirajućih talasa na visokoj temperaturi dobijene su veoma aktivne nanostrukturne silikatne faze. Proces hidratacije CS faza je analiziran pomoću XRD i FTIR, predložen je mehanizam hidratacije i ukazano na teškoće u utvrđivanju tačne reakcije, kao i na problem utvrđivanja tačne strukture tobermorita

Metode magnetronskog raspršivanja za površinsku modifikaciju memorijskih legura za primenu u ortodonciji i endodonciji

Various magnetron-sputtering methods for surface modification of shape memory alloys (SMA) are described in this paper. These methods belong to the most effective methods, which enable mechanical reinforcing of the SMA, showing numerous advantages over conventional methods of electro-polishing. In addition, surface modified SMA, particularly with equiatomic TiNi coatings, is crucial for further development of various endodontic instruments; wires and brackets used for orthodontic teeth movements. Active coatings with bactericide properties and coatings that can be used as barrier for release of toxic Ni ions from the bulk body of SMA obtained by various magnetron-sputtering methods can be successfully combined. Therefore, the review of these methods is given in this paper, with their main characteristics and drawbacks. Magnetron sputtering deposition involves surface modification of SMA in a single-layer, multilayer, graded layers, and nanocomposite thin coatings for obtaining systems with superior "functional" characteristics. These are hardness, scratch, abrasion, and erosion resistance, improved adhesion to various technologically important substrate materials such as polymers, hydrophobicity or hydrophilicity, long-term chemical, thermal, and environmental stability, gas and vapor impermeability, and others. This paper is critical review of the advances in the development of magnetron sputtering modified SMA products in dentistry, with in advance predictable physicochemical, structural and antimicrobial properties.U ovom radu su opisane različite metode magnetronskog raspršivanja za površinsku modifikaciju memorijskih legura (shape memory alloys - SMA). Ove metode spadaju u najefikasnije metode koje omogućavaju mehaničko ojačavanje SMA, pokazujući brojne prednosti u odnosu na konvencionalne metode elektropoliranja, koje su najčešće korišćene u savremenoj ortodontskoj i endodontskoj praksi. Pored toga, površinski modifikovane SMA, posebno sa ekviatomskim Ti i Ni udelima unutar prevlake, presudne su za dalji razvoj različitih endodontskih instrumenata, žica i konzola koje se koriste za ortodontska pomeranja zuba. Aktivne prevlake sa baktericidnim svojstvima i prevlake koje služe kao barijere protiv otpuštanja toksičnih Ni jona iz SMA unutar organizma mogu biti dobijene različitim metodama magnetronskog raspršivanja, pri čemu se različite varijante ove metode mogu uspešno kombinovati. Zbog svega toga u ovom radu je dat pregled ovih metoda, sa njihovim glavnim karakteristikama i nedostacima. Magnetronsko nanošenje raspršivanjem uključuje površinsku modifikaciju SMA u jednoslojnim, višeslojnim, gradiranim slojevima i nanokompozitne tanke prevlake za dobijanje sistema sa superiornim "funkcionalnim" karakteristikama, kao što su vrlo visoka tvrdoća, otpornost na habanje, abraziju i eroziju, poboljšano prijanjanje na različite tehnološki važne supstratne materijale kao što su polimeri, hidrofobnost ili hidrofilnost, dugotrajna hemijska, termička i ekološka stabilnost, nepropusnost gasa i para i drugi. Ovaj rad predstavlja neku vrstu kritičkog pregleda napretka u razvoju magnetronskog raspršivanja modifikovanih SMA proizvoda u stomatologiji, sa unapred predvidljivim fizičko-hemijskim, strukturnim i antimikrobnim osobinama

Skafoldi u inženjerstvu koštanog tkiva

Treatment of bone tissue injuries and diseases is still a great challenge for surgeons, but also for researchers who work with materials. Today stem cells are commonly used in bone tissue engineering. However, advances in biocompatible materials design, especially biodegradable porous structure (scaffold) is gaining an important role in the treatment of diseased bone tissue. The basic advantage of these carriers is specifically designed scaffold with defined porosity and pore structure that is favourable for cells settlement. Scaffolds are most commonly used as ceramic brackets because they have excellent characteristics in biodegradation and bioactivity. The process of scaffold production is important because the appropriate technology must ensure control of liquids and reproducibility of scaffold production through standardized process. The aim of this study was to present some of different procedures of scaffold production in bone tissue engineering and point out the advantages and disadvantages of these methods.Terapija i lečenje brojnih povreda i oboljenja koštanog tkiva je još uvek veliki izazov za hirurge, ali i za one istraživače koji se bave materijalima. Na polju inženjerstva koštanog tkiva danas se najčešće koriste matične ćelije. Međutim, napredak u dizajniranju biokompatibilnih materijala, a posebno biodegradibilnih poroznih struktura (skafolda) sve više dobija vrlo značajnu ulogu u lečenju obolelih koštanih tkiva. Specifično dizajnirani skafoldi sa definisanom poroznošću i strukturom pora koja je povoljna za naseljavanje ćelija osnovna je prednost ovih nosača. Skafoldi se najčešće koriste kao keramički nosači jer imaju izvanredne osobine vezane za biodegradaciju i jako izraženu bioaktivnost. Postupak izrade skafolda je vrlo važan jer se odgovarajućom tehnologijom mora obezbediti kontrola tečnosti i reproduktivnost izrade skafolda kroz standardizaciju procesa. Cilj ovog rada je bio da se predstave različiti metodološki postupci izrade skafolda u inženjerstvu koštanog tkiva i ukaže na određene prednosti i nedostatke tih metoda

Abnormalities in enamel structure and their association with systemic diseases and syndromes

Etiology of abnormalities in tooth structure has been subject of numerous studies but still has not been fully understood. Heredity is an established etiological factor for many types of structural anomalies of the teeth. Factors that cause changes in enamel structure may be genetic, immunologic and teratogenic or systemic diseases. Genetic changes may include individual genes, micro deletions or chromosomal defects. Systemic diseases can be associated with anomalies of tooth structure and diversity of clinical picture requires a multidisciplinary approach to the therapy. Amelogenesis imperfecta (AI) represents a large group of structural abnormalities of the teeth. AI can exist independently or as a part of large number of syndromes and systemic diseases. Knowledge of clinical presentation, etiology, pathogenesis of structural anomalies of the teeth and their association with certain systemic diseases is of great importance to everyday dental practice in terms of prevention, prognosis and therapy. Also, it is necessary to expand basic knowledge of pediatricians in regards to the clinical picture of anomalies in tooth structure and their possible association with a wide range of systemic diseases and syndromes, in order to provide comprehensive clinical treatment. Therefore, the aim of this study was to present etiopathogenesis and classification and to describe the most important abnormalities of enamel structure and their association with systemic diseases and syndromes

Biological aspects of application of nanomaterials in tissue engineering

Millions of patients worldwide need surgery to repair or replace tissue that has been damaged through trauma or disease. To solve the problem of lost tissue, a major emphasis of tissue engineering (TE) is on tissue regeneration. Stem cells and highly porous biomaterials used as cell carriers (scaffolds) have an essential role in the production of new tissue by TE. The cellular component is important for the generation and establishment of the extracellular matrix, while a scaffold is necessary to determine the shape of the newly formed tissue and facilitate migration of cells into the desired location, as well as their growth and differentiation. This review describes the types, characteristics and classification of stem cells. Furthermore, it includes functional features of cell carriers - biocompatibility, biodegradability and mechanical properties of biomaterials used in developing state-of-the-an scaffolds for TE applications, as well as suitability for different tissues. Moreover, it explains the importance of nanotechnology and defines the challenges and the purpose of future research in this rapidly advancing field