Photofunctionalization of titanium: an alternative explanation of its chemical-physical mechanism

Objectives To demonstrate that titanium implant surfaces as little as 4 weeks from production are contaminated by atmospheric hydrocarbons. This phenomenon, also known as biological ageing can be reversed by UVC irradiation technically known as photofunctionalization. To propose a new model from our experimental evidence to explain how the changes in chemical structure of the surface will affect the adsorption of amino acids on the titanium surface enhancing osteointegration. Methods In our study XPS and AES were used to analyze the effects of UVC irradiation (photofunctionalization) in reversing biological ageing of titanium. SEM was used to analyze any possible effects on the topography of the surface. Results UVC irradiation was able to reverse biological ageing of titanium by greatly reducing the amount of carbon contamination present on the implant surface by up to 4 times, while the topography of the surface was not affected. UVC photon energy reduces surface H2 O and increases TiOH with many -OH groups being produced. These groups explain the superhydrophilic effect from photofunctionalization when these groups come into contact with water. Significance Photofunctionalization has proven to be a valid method to reduce the amount of hydrocarbon contamination on titanium dental implants and improve biological results. The chemisorption mechanisms of amino acids, in our study, are dictated by the chemical structure and electric state present on the surface, but only in the presence of an also favourable geometrical composition at the atomical level

Artificial Light Increases Local Predator Abundance, Predation Rates, and Herbivory.

Human activity is rapidly increasing the radiance and geographic extent of artificial light at night (ALAN) leading to alterations in the development, behavior, and physiological state of many organisms. A limited number of community-scale studies investigating the effects of ALAN have allowed for spatial aggregation through positive phototaxis, the commonly observed phenomenon of arthropod movement toward light. We performed an open field study (without restricted arthropod access) to determine the effects of ALAN on local arthropod community composition, plant traits, and local herbivory and predation rates. We found strong positive phototaxis in 10 orders of arthropods, with increased (159% higher) overall arthropod abundance under ALAN compared to unlit controls. The arthropod community under ALAN was more diverse and contained a higher proportion of predaceous arthropods (15% vs 8%). Predation of immobilized flies occurred 3.6 times faster under ALAN; this effect was not observed during the day. Contrary to expectations, we also observed a 6% increase in herbivory under ALAN. Our results highlight the importance of open experimental field studies in determining community-level effects of ALAN

Kinetic Mechanism of the Ca2+-Dependent Switch-On and Switch-Off of Cardiac Troponin in Myofibrils

The kinetics of Ca2+-dependent conformational changes of human cardiac troponin (cTn) were studied on isolated cTn and within the sarcomeric environment of myofibrils. Human cTnC was selectively labeled on cysteine 84 with N-((2-(iodoacetoxy)ethyl)-N-methyl)amino-7-nitrobenz-2-oxa-1,3-diazole and reconstituted with cTnI and cTnT to the cTn complex, which was incorporated into guinea pig cardiac myofibrils. These exchanged myofibrils, or the isolated cTn, were rapidly mixed in a stopped-flow apparatus with different [Ca2+] or the Ca2+-buffer 1,2-Bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid to determine the kinetics of the switch-on or switch-off, respectively, of cTn. Activation of myofibrils with high [Ca2+] (pCa 4.6) induced a biphasic fluorescence increase with rate constants of >2000 s−1 and ∼330 s−1, respectively. At low [Ca2+] (pCa 6.6), the slower rate was reduced to ∼25 s−1, but was still ∼50-fold higher than the rate constant of Ca2+-induced myofibrillar force development measured in a mechanical setup. Decreasing [Ca2+] from pCa 5.0–7.9 induced a fluorescence decay with a rate constant of 39 s−1, which was approximately fivefold faster than force relaxation. Modeling the data indicates two sequentially coupled conformational changes of cTnC in myofibrils: 1), rapid Ca2+-binding (kB ≈ 120 μM−1 s−1) and dissociation (kD ≈ 550 s−1); and 2), slower switch-on (kon = 390s−1) and switch-off (koff = 36s−1) kinetics. At high [Ca2+], ∼90% of cTnC is switched on. Both switch-on and switch-off kinetics of incorporated cTn were around fourfold faster than those of isolated cTn. In conclusion, the switch kinetics of cTn are sensitively changed by its structural integration in the sarcomere and directly rate-limit neither cardiac myofibrillar contraction nor relaxation

Temperature effects on the physiological status and reflex impairment in European grayling Thymallus thymallus from catch-and release angling

There is a growing body of research communicating how angler behaviour can be adjusted and optimised to reduce fish injury and impairment resulting from the capture of recreationally angled fishes. However, few studies have focused on how individual and interacting abiotic variables influence the outcomes of catch and release (C&R) angling. A population of European grayling Thymallus thymallus at their upper thermal limit of their geographic distribution provided a model cold-water species that was representative of other fishes sensitive to climate warming impacts and that are subjected to C&R across different seasons. Here, C&R angling for T. thymallus was conducted during summer (>15 °C) and winter (15 °C, fish took significantly longer to regain equilibrium (178 ± 44 s) than at 15 °C versus <10 °C, In entirety, these results suggest that stress responses and post-release mortality risk in cold-water fishes subjected to C&R could be reduced via temperature-informed fishery management practises, and by minimising, or ideally eliminating, air exposur

Ocena wybranych rozkładów teoretycznych trwania życia do analizy lojalności klientów na przykładzie europejskiego banku detalicznego

One of the key elements related to calculating Customer Lifetime Value is to estimate the duration of a client’s relationship with a bank in the future. This can be done using survival analysis. The aim of the article is to examine which of the known distributions used in survival analysis (Weibull, Exponential, Gamma, Log‑normal) best describes the churn phenomenon of a bank’s clients. If the aim is to estimate the distribution according to which certain units (bank customers) survive and the factors that cause this are not so important, then parametric models can be used. Estimation of survival function parameters is faster than estimating a full Cox model with a properly selected set of explanatory variables. The authors used censored data from a retail bank for the study. The article also draws attention to the most common problems related to preparing data for survival analysis.Jednym z kluczowych elementów związanych z wyliczaniem wartości klienta w czasie (Customer Life Time Value) jest oszacowanie długości trwania relacji klienta z bankiem w przyszłości. Można ją oszacować z wykorzystaniem metod analizy przeżycia. Celem artykułu jest sprawdzenie, który ze znanych rozkładów wykorzystywanych w analizie przeżycia (Weibulla, wykładniczy, gamma, logarytmicznie normalny) najlepiej opisuje zjawisko odejść klientów z banku. Jeśli celem jest oszacowanie rozkładu, według którego „przeżywają” określone jednostki (klienci banku), a czynniki, które to powodują, nie są aż tak istotne, to modele parametryczne mogą być wykorzystane. Oszacowanie parametrów funkcji przeżycia jest szybsze niż oszacowanie pełnego modelu Coxa z odpowiednio dobranym zestawem zmiennych objaśniających. Do badania wykorzystano dane cenzurowane banku detalicznego. W artykule zwrócono uwagę na najczęstsze problemy związane z przygotowaniem danych do analizy przeżycia

Segmentacja klientów banku wspomagana algorytmami ewolucyjnymi

Celem głównym przeprowadzonych prac empirycznych jest zbadanie efektywności działania algorytmu ewolucji różnicowej do grupowania klientów, które mogą posłużyć do budowy segmentów biznesowych. W niniejszym badaniu cel główny został podzielony na cele szczegółowe, które mają w założeniu: 1. Ocenić efektywność działania algorytmu ewolucji różnicowej do grupowania klientów banku. 2. Ocenić efektywności działania algorytmu ewolucji różnicowej w porównaniu do algorytmu k-średnich. Hipotezą główną pracy jest stwierdzenie, że algorytmy ewolucyjne użyte do grupowania klientów pozwalają na znalezienie jednorodnych grup klientów, które mogą posłużyć do budowy segmentów biznesowych. Dla każdego elementu badań hipotezy badawcze konstruowane były tak, aby potwierdzić lub zaprzeczyć występowaniu określonego zjawiska. W badaniu postanowiono sprawdzić następujące hipotezy badawcze: 1. Algorytmy ewolucyjne umożliwiają wyodrębnienie nowych grup klientów i tworzenie segmentów biznesowych. 2. Algorytmy ewolucyjne sygnalizują o zmieniającej się strukturze klientów banku. 3. Grupy utworzone dla klientów bez zgody marketingowej różnią się od grup utworzonych dla klientów ze zgodą marketingową. Segmentacja wspomagana algorytmami ewolucyjnymi lepiej określa potencjalny segment klienta niż tradycyjne metody segmentacji klientów

Regression model of water demand for the city of Lodz as a function of atmospheric factors

One of the Sustainable Development Goals (Goal 6) set by the United Nations is to provide people with access to water and sanitation through sustainable water resources management. Water supply companies carrying out tasks commissioned by local authorities ensure there is an optimal amount of water in the water supply system. The aim of this study is to present the results of the work on a statistical model which determined the influence of individual atmospheric factors on the demand for water in the city of Lodz, Poland, in 2010-2019. In order to build the model, the study used data from the Water Supply and Sewage System Company (Zakład Wodociągów i Kanalizacji Sp. z o.o.) in the city of Lodz complemented with data on weather conditions in the studied period. The analysis showed that the constructed models make it possible to perform a forecast of water demand depending on the expected weather conditions

Intrahepatic icterus in pigs: rare clinical sign in porcine circovirus type 2 systemic disease

Icterus is a yellow discolouration of tissue and blood plasma due to a disorder of the bilirubin metabolism. This case report describes two porcine circovirus type 2 (PCV2) outbreaks in a fattening farm (F1) and a breeding farm (F2). At F1, pigs had intradermal bleedings and wasting, and three pigs showed icterus. At F2, suckling and weaning pigs (WPs) had an icterus and were wasted. Three fattening pigs (F1), one suckling piglet and one WP (F2) were dissected. Additional investigations included histology, PCV2 immunohistochemistry (IHC), fluorescence in situ hybridisation (FISH) of tissue samples, PCR including sequencing of the PCV2 strains and next-generation sequencing (NGS) of liver samples. Three of the five dissected pigs showed a lymphohistiocytic, periportal hepatitis with disruption of the hepatic cord architecture. PCV2 was detected by IHC, FISH, PCR and NGS in several organs of the pigs. In both farms, sequencing revealed a PCV2b genotype

Comparison Study of PVD Coatings: TiN/AlTiN, TiN and TiAlSiN Used in Wood Machining

In this paper, we analyze the possibilities of the protection of tools for wood machining with PVD (Physical Vapor Deposition) hard coatings. The nanolayered TiN/AlTiN coating, nanocomposite TiAlSiN coatings, and single layer TiN coating were analyzed in order to use them for protection of tools for wood machining. Both nanostructured coatings were deposited in an industrial magnetron sputtering system on the cutting blades made of sintered carbide WC-Co, while TiN single layer coating was deposited by evaporation using thermionic arc. In the case of TiN/AlTiN nanolayer coatings the thickness of the individual TiN and AlTiN layer was in the 5–10 nm range, depending on the substrate vertical position. The microstructure and chemical composition of coatings were studied by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) method. Additionally, in the case of the TiN/AlTiN coating, which was characterized by the best durability characteristics, the transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) methods were applied. The coatings adhesion to the substrate was analyzed by scratch test method combined with optical microscopy. Nano-hardness and durability tests were performed with uncoated and coated blades using chipboard. The best results durability characteristics were observed for TiN/AlTiN nanolayered coating. Performance tests of knives protected with TiN and TiAlSiN hard coatings did not show significantly better results compared to uncoated ones

Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.

<p>Atomic concentration of carbon, nitrogen, oxygen and titanium calculated from C1s, N1s, O1s, Al2p, Ti2p and F1s core lines for BASE and RAPID implants.</p