THE DYNAMIC CIPHERS – NEW CONCEPT OF LONG-TERM CONTENT PROTECTING

In the paper the original concept of a new cipher, targeted at this moment forcivil applications in technology (e.g. measurement and control systems) and business (e.g.content protecting, knowledge-based companies or long-term archiving systems) is presented.The idea of the cipher is based on one-time pads and linear feedback shift registers. Therapidly changing hardware and software environment of cryptographic systems has beentaken into account during the construction of the cipher. The main idea of this work is tocreate a cryptosystem that can protect content or data for a long time, even more than onehundred years. The proposed algorithm can also simulate a stream cipher which makes itpossible to apply it in digital signal processing systems such as those within audio and videodelivery or telecommunication.Content protection, Cryptosystem, Dynamic cryptography, Linear Feedback ShiftRegisters, Object-oriented programming, One-time pad, Random key, random number generators,Statistical evaluation of ciphers.

Time Consumption of Skidding in Mature Stands Performed by Winches Powered by Farm Tractor

The aim of the present research was to determine the characteristics of time consumption in skidding by winch. The research was conducted in pine, fir, spruce and beech mature stands. It covered the operation of skidding from the stand to the skid trail at the distance of up to 50 m. A time study was performed for skidding operations, timber volume and thinning intensity. The average time consumption of skidding in the operational time, assessed in the examined mature stands, amounted to approximately 18 min/m3. Significant differences were observed in frequency levels between early thinnings (24 min/m3) and late ones (13 min/m3). The operational time structure for skidding by winch was characterized by a large share of auxiliary time: 71%. Out of that time, 30% was used for attaching and detaching the load and 36% for the transfer. Approximation was also done of the multiple regression equations. The equations described changes in skidding time consumption, i.e. the Empirical Efficiency Index (EST). The changes depended on environmental factors (stand, cutting category), elements of the working day structure (the share of a given time category in a shift) and task intensity (ratio of the number of harvested trees per area unit). The strongest correlations between the EST and the analyzed variables were observed for the factors related to the percentage of time required for attaching and detaching the load and factors related to operation intensity

Identyfikacja czynników stymulujących fototoksyczne działanie melaniny z nabłonka upigmentowanego siatkówki

Główną funkcją komórek nabłonka upigmentowanego siatkówki jest utrzymanie w dobrym stanie komórek fotoreceptorowych, co umożliwia prawidłowy proces widzenia. Warunki fizykochemiczne panujące w siatkówce, a mianowicie duże stężenia tlenu i substancji światłoczułych przy jednoczesnej ekspozycji na światło, sprzyjają zaistnieniu reakcji fotouczulanych z udziałem reaktywnych form tlenu. Komórki RPE wyposażone są w szereg czynników obrony przed stresem oksydacyjnym, wśród których występuje melanina zawarta w melanosomach. Warstwa komórek RPE jest tkanką postmitotyczną, więc nie ma możliwości regeneracji poprzez wymianę komórek. Melanina w komórkach RPE syntetyzowana jest w dużych ilościach jedynie w życiu płodowym, pojawiające się z wiekiem zmiany w melaninie kumulują się. W pracy badano wpływ wieku na właściwości przeciw- i proutleniające melanosomów ludzkich. Zaobserwowano wyraźny wzrost fotoreaktywności melanosomów z wiekiem dawców, objawiający się zwiększoną konsumpcją tlenu oraz produkcją anionorodnika ponadtlenkowego, obserwowanych odpowiednio za pomocą tlenometrii EPR oraz pułapkowania spinowego. Oprócz pomiaru całych ziarnistości, badano właściwości różnych części składowych melanosomu. Detekcję reaktywnych form tlenu generowanych przez rozpuszczalną w chloroformie składową melanosomów prowadzono przy użyciu HPLC z detektorem elektrochemicznym. Chloroformowe ekstrakty z melanosomów, umieszczone w peroksydowalnych liposomach wykazywały zwiększoną generację reaktywnych form tlenu, głównie tlenu singletowego. Celem przeprowadzenia dokładniejszych badań zmian właściwości melaniny posłużono się układem modelowym : postarzanymi światłem melanosomami zwierzęcymi. Badano sam proces fotodegradacji melanosomów zwierzęcych światłem niebieskim oraz zmiany właściwości melaniny temu towarzyszące. Posługując się spektroskopią EPR obserwowano zwiększenie produkcji anionorodnika ponadtlenkowego przez naświetlane mealnosomy. Badano w jaki sposób degradacja melanosomów wpływa na zdolność hamowania reakcji Fentona. Stwierdzono znacznie mniejszą zdolność kompleksowania jonów metali przejściowych, co może mieć wpływ na ogólną homeostazę oksydoredukcyjną w komórce. Aby potwierdzić zmiany właściwości przeprowadzono doświadczenia na hodowlach komórkowych, podając komórkom ARPE-19 melanosomy natywne i degradowane. Zaobserwowano znaczący wzrost fototoksyczności melanosomów poddanych fotostarzeniu w porównaniu z melanosomami natywnymi. W doświadczeniach nad molekularnym mechanizmem zaobserwowanych zjawisk badano zmiany struktur wewnętrznych melanosomów posługując się wpływem jonów Dy(III) na szybkość relaksacji spinowo-siecowej centrów paramagnetycznych melaniny. Stosując impulsową spektroskopię EPR udało się zaobserwować zwiększony wpływ jonów na czas relaksacji dla melanosomów degradowanych, co może wskazywać na rozluźnienie struktur polimeru melaniny. Stwierdzono też zwiększony potencjał fotoredukcyjny melanosomów fotodegradowanych w nieobecności tlenu. Melanosomy degradowane znacznie szybciej redukowały znacznik spinowy pod wpływem światła. Zaobserwowano także zmiany charakterystycznego sygnału EPR melaniny, mierzonego w zaawansowanym technicznie paśmie W, pod wpływem fotodegradacji. Może to sugerować zmianę geometrii wokół centrów paramagnetycznych melaniny. Uzyskane obserwacje potwierdzają znaczący wzrost fotoreaktywności melanosomów ludzkich wraz z wiekiem. Doświadczenia na postarzanych światłem melanosomach zwierzęcych potwierdzają tą hipotezę, jak również pozwalają wyciągnąć wnioski na temat zmian właściwości melaniny. Najprawdopodobniej struktura wewnętrzna w cząsteczce melaniny ulega rozluźnieniu, co skutkuje łatwiejszym dostępem zewnętrznych reagentów do wolnorodnikowych centrów melaniny i mniejszą zdolnością do przechwytywania jonów metali przejściowych. Natywne melanosomy w zależności od warunków doświadczalnych mogą wykazywać właściwości zarówno pro- jak i antyutleniające. Wraz z postępującym procesem fotodegradacji zaczyna dominować aktywność proutleniająca przy jednoczesnym spadku wydajności procesów przeciwutleniajacych. Efekty te mogą sprzyjać występowaniu zaburzeń procesu widzenia, prowadząc do patologii siatkówki takich jak starcze zwyrodnienie plamki żółtej (AMD)

Productivity and Working Time Structure of Timber Forwarding in Flatland Thinned Pine Stand with the Use of Farm Tractors

Farm tractors are very popular in Poland and other European countries. When coupled with trailers equipped with a crane with a grapple, they are also used, especially in easily accessible, flat terrain, for timber forwarding in the CTL (Cut-to-Length) method. A comparative analysis of working time and productivity was performed on two forwarding units, consisting of a farm tractor Ursus and a Farma trailer with the load capacity of 6 tons, as well as a farm tractor Valtra Valmet and a Palms trailer with the capacity of 9 tons, which forwarded wood in a mature pine stand. An analysis was done for 64 work cycles with an average load volume of 2.1 m3 for the former unit, and 36 cycles with an average load volume of 7.9 m3 for the latter. The working time structure of both units was similar. During work, tractor operators spent most time, i.e. over 35%, loading the timber, then travelling with the load and unloading. The lowest share in the work cycle, around 5%, belonged to travelling without a load and forwarding. The average forwarding time for the Farma unit amounted to 33 minutes and was about twice shorter than that for the Palms unit, amounting to 64 minutes. The distance covered during loaded travel was the only factor that had a significant influence on the duration of forwarding cycles. The coefficients of correlation between these variables were 0.56–0.76. The net productivity obtained in the operating time of the Palms unit was 7.5 m3×PMH-1 and was almost twice as high as that of the Farma unit, i.e. 3.8 m3×PMH-1. For both units multiple regression models were developed, in which forwarding cycles productivity is calculated based on the volume of the transported load and the distance of loaded travel

Productivity and Time Consumption of Timber Extraction with a Grapple Skidder in Selected Pine Stands

This paper presents the results of the study on work time and productivity of the John Deere 548G-III grapple skidder operating in pine stands on flat terrain. The research covered three types of treatment: late thinning, removal cutting in openings and clear cutting in openings. The average skidding distance was between 120 and 250 m. In the clear-cut stands, a mean duration of a skidding cycle accounted for 12 minutes, while in the thinned ones it was longer, lasting ca. 16 minutes. The investigators performed an estimate of parameters of multiple regression models, which revealed dependences between: Þ duration of skidding cycles and stand conditions, number of logs per load and skidding distance, and Þ productivity achieved in specific skidding cycles and the above-mentioned variables, as well as wood volume per load. The highest productivity within the productive work time of a skidder was recorded in the stand where removal cutting in openings was performed; it exceeded 14 m3×h-1. In other stands, the efficiency was lower, not greater than 9 m3×h-1. However, differences between the productivity achieved within the productive work time and that recorded for the work place time did not exceed 20%, which indicated that skidding operations in the stands under scrutiny were organised properly

Photodynamic inactivation of Candida albicans with imidazoacridinones : influence of irradiance, photosensitizer uptake and reactive oxygen species generation

The increasing applicability of antifungal treatments, the limited range of available drug classes and the emergence of drug resistance in Candida spp. suggest the need for new treatment options. To explore the applicability of C. albicans photoinactivation, we examined nine structurally different imidazoacridinone derivatives as photosensitizing agents. The most effective derivatives showed a >10(4)-fold reduction of viable cell numbers. The fungicidal action of the three most active compounds was compared at different radiant powers (3.5 to 63 mW/cm2), and this analysis indicated that 7 mW/cm2 was the most efficient. The intracellular accumulation of these compounds in fungal cells correlated with the fungicidal activity of all 9 derivatives. The lack of effect of verapamil, an inhibitor targeting Candida ABC efflux pumps, suggests that these imidazoacridinones are not substrates for ABC transporters. Thus, unlike azoles, a major class of antifungals used against Candida, ABC transporter-mediated resistance is unlikely. Electron paramagnetic resonance (EPR)-spin trapping data suggested that the fungicidal light-induced action of these derivatives might depend on the production of superoxide anion. The highest generation rate of superoxide anion was observed for 1330H, 1610H, and 1611. Singlet oxygen production was also detected upon the irradiation of imidazoacridinone derivatives with UV laser light, with a low to moderate yield, depending on the type of compound. Thus, imidazoacridinone derivatives examined in the present study might act via mixed type I/type II photodynamic mechanism. The presented data indicate lack of direct correlation between the structures of studied imidazoacridinones, cell killing ability, and ROS production. However, we showed for the first time that for imidazoacridinones not only intracellular accumulation is necessary prerequisite of lethal photosensitization of C. albicans, but also localization within particular cellular structures. Our findings present IA derivatives as efficient antifungal photosensitizers with a potential to be used in local treatment of Candida infection

Nitric oxide synthase inhibitor attenuates the effects of repeated restraint stress on synaptic transmission in the paraventricular nucleus of the rat hypothalamus

Corticotropin-releasing hormone (CRH)-synthesizing parvocellular neuroendocrine cells (PNCs) of the hypothalamic paraventricular nucleus (PVN) play a key role in the activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Several studies have demonstrated that synaptic inputs to these cells may undergo stress-related enhancement but, on the other hand, it has been reported that exposition to the same stressor for prolonged time periods may induce a progressive reduction in the response of the HPA axis to homotypic stressors. In the present study rats were subjected to 10 min restraint sessions, repeated twice daily for 3 or 7 days. Miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs) were then recorded from PNCs in ex vivo hypothalamic slice preparations obtained 24 h after the last restraint. Restraint stress repeated over 3 days resulted in increased mean frequency and decreased rise time and decay time constant of mEPSCs, accompanied by a decrease in the excitability of PNCs, however, no such changes were evident in slices obtained from rats subjected to restraint over 7 days. There were no changes in mIPSCs after repeated restraint. Administration of the unspecific nitric oxide synthase (NOS) blocker Nω-Nitro-L-arginine (L-NNA) before each restraint, repeated over 3 days, prevented the occurrence of an increase in mEPSC frequency. However, animals receiving L-NNA and subjected to repeated restraint had similar changes in PNCs membrane excitability and mEPSC kinetics as stressed rats not receiving L-NNA. Comparison of the effects of a single 10 min restraint session followed by either an immediate or delayed (24 h) decapitation revealed an increase in the mean mEPSC frequency and a decrease in the mean mIPSC frequency in slices prepared immediately after restraint, with no apparent effects when slice preparation was delayed by 24 h. These results demonstrate that restraint, lasting 10 min and repeated twice daily for 3 days, induces a selective and long-lasting enhancement of excitatory synaptic input onto PNCs, partially by a NOS-dependent mechanism, and reduces PNC excitability, whereas prolongation of repeated stress for up to 7 days results in an adaptation

The Araucaria Project. The Distance to the Local Group Galaxy WLM from Near-Infrared Photometry of Cepheid Variables

We have obtained deep images in the near-infrared J and K filters for several fields in the Local Group galaxy WLM. We report intensity mean magnitudes for 31 Cepheids located in these fields which we previously discovered in a wide-field optical imaging survey of WLM. The data define tight period-luminosity relations in both near-infrared bands which we use to derive the total reddening of the Cepheids in WLM and the true distance modulus of the galaxy from a multiwavelength analysis of the reddened distance moduli in the VIJK bands. From this, we obtain the values E(B-V) = 0.082 $\pm$ 0.02, and $(m-M)_{0} = 24.924 \pm 0.042$ mag, with a systematic uncertainty in the distance of about $\pm$ 3%. This Cepheid distance agrees extremely well with the distance of WLM determined from the I-band TRGB method by ourselves and others. Most of the reddening of the Cepheids in WLM (0.06 mag) is produced inside the galaxy, demonstrating again the need for an accurate determination of the total reddening and/or the use of infrared photometry to derive Cepheid distances which are accurate to 3% or better, even for small irregular galaxies like WLM.Comment: latex, 6 figures. accepted to Ap