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Encryption is a very important way to secure data in storage and communication, and it is a process of encoding messages or information in such a manner that only authorised persons can access it. Different techniques are used to protect confidential image data against illicit access. In image encryption using chaotic systems, most authors use or design algorithms to generate the initial parameters' values from the secret key. However, as the key size depends on the number of these parameters, the used algorithms show little sensitivity to small changes in the key. To enhance both security and sensitivity in the choice of the initial parameters, this work combines the use of the Grain‐128a stream cipher algorithm with two‐dimensional Zaslavsky chaotic map. Firstly, the Grain‐128a algorithm is applied to generate the required parameters of Zaslavsky's chaotic map from a fixed length 256‐bit secret key. Secondly, the sequences generated by the chaotic map are used to encrypt the image using a bit confusion and diffusion process. The simulation results on greyscale, colour, binary, indexed, and medical images together with the scores obtained in the evaluation of the algorithm show that the proposed method is very sure and effective in encrypting images of any size and any type. [ABSTRACT FROM AUTHOR]

What is it to see a stove as world (als Welt) and why does the early Wittgenstein use such a curious example to describe what it means to see something as significant (bedeutend)? I argue that Wittgenstein's odd choice can be best understood in the light of a conceptual relation between value and semantic meaning. To that purpose, I draw attention to his use of the word Bedeutung to denote value, and to the direct connection he draws between seeing as world and seeing with the whole logical space. To see a stove as bedeutend, I conclude, is to see it against the background of the propositional contexts in which a stove figures meaningfully. [ABSTRACT FROM AUTHOR]

Through Minos transposon mutagenesis we obtained A. nidulans mutants resistant to 5-fluorouracil due to insertions into the upstream region of the uncharacterized gene nmeA, encoding a Major Facilitator Superfamily (MFS) transporter. Minos transpositions increased nmeA transcription, which is otherwise extremely low under all conditions tested. To dissect the function of NmeA we used strains overexpressing or genetically lacking the nmeA gene. Strains overexpressing NmeA are resistant to toxic purine analogues, but also, to cadmium, zinc and borate, whereas an isogenic nmeAΔ null mutant exhibits increased sensitivity to these compounds. We provide direct evidence that nmeA overexpression leads to efflux of adenine, xanthine, uric acid and allantoin, the latter two being intermediate metabolites of purine catabolism that are toxic when accumulated cytoplasmically due to relevant genetic lesions. By using a functional GFP-tagged version we show that NmeA is a plasma membrane transporter. Homology modeling and docking approaches identified a single purine binding site and a tentative substrate translocation trajectory in NmeA. Orthologues of NmeA are present in all Aspergilli and other Eurotiomycetes, but are absent from other fungi or non-fungal organisms. NmeA is thus the founding member of a new class of transporters essential for fungal success under specific toxic conditions. [ABSTRACT FROM AUTHOR]

Background. BK virus-associated nephropathy (BKVAN) can be diagnosed only with renal graft biopsy. Definitive diagnosis of BKVAN requires demonstration of BK virus (BKV) replication in renal allograft tissues. Non-invasive analysis of urine and blood is considered essential in screening renal transplant recipients. Patients and methods. This study evaluated prospectively the replication of BKV in plasma and urine with qualitative and quantitative real-time polymerase chain reaction in 32 de novo (group A) and 34 chronic (group B) renal transplant recipients and the long-term impact on graft function. Results. In group A, 456 samples (228 plasma, 228 urine) were examined and BKV was detected in 31 (31/228, 14%) samples of plasma and 57 (57/228, 25%) samples of urine in 20 (20/32, 62.5%) and 23 (23/32, 72%) recipients, respectively. Incidence of viremia and viruria increased during the first 6 months presenting a peak the third postoperative month (viremia: 28% and viruria: 31%). Immune suppressive treatment with tacrolimus showed significant relation with viremia. Renal graft function in de novo renal transplant recipients remained stable throughout the follow-up period without influence of BKV replication. In group B, incidence of viremia and viruria were 3% (1/34) and 9% (3/34) correspondingly, indicating that after the first post-transplant year the risk of BKV re-activation is diminished. Conclusion. The highest incidence of BK viremia and viruria is observed the third post-transplantation month, confirming previously published studies in Europe and the United States, and long-term follow up shows that BKV replication decreases significantly after the third post-transplant month and even transient viremia or viruria does not have an impact on renal function. [ABSTRACT FROM AUTHOR]

Background and Aim: Monotherapy has been proven insufficient in achieving sustained control of chronic hepatitis B. We aimed to assess the efficacy of combined sequential administration of lamivudine and pegylated interferon alfa-2b in patients with hepatitis Be antigen (HBeAg)-negative chronic hepatitis B. Methods: Eighteen patients were given sequential combination treatment starting with 3 months of lamivudine monotherapy followed by 9 months of pegylated interferon alfa-2b (after a 3-month period of concomitant administration of the two drugs) and 24 patients received lamivudine monotherapy. Results: At the end of treatment, 88.9% of the patients who received sequential combination treatment and 70.8% of those who received lamivudine monotherapy had hepatitis B virus (HBV) DNA levels below 400 copies/mL ( P = not significant). At the end of treatment, 72.2% of the patients who received sequential combination treatment and 70.8% of those who received lamivudine monotherapy achieved alanine aminotransferase normalization ( P = not significant). After 12 months of follow up, 33.3% of the patients who received sequential combination treatment and 16.7% of those who received lamivudine monotherapy had HBV-DNA levels below 400 copies/mL ( P = 0.4). After 12 months of follow up, 72.2% of the patients who received sequential combination treatment and 25.0% of those who received lamivudine monotherapy had normal alanine aminotransferase levels ( P < 0.01). Twenty-five percent of the patients in the lamivudine monotherapy group had virological breakthrough compared to none in the sequential combination treatment group ( P = 0.06). Conclusions: Sequential combination treatment is able to improve sustained biochemical response rates and prevent the emergence of lamivudine-resistant mutants in patients with HBeAg-negative chronic hepatitis B. [ABSTRACT FROM AUTHOR]

Background: Monotherapy with a single antiviral agent is insufficient in controlling hepatitis B virus infection in the majority of patients with anti-HBe positive chronic hepatitis B. Interferon/long-term lamivudine combination therapy was evaluated to determine if this strategy would improve treatment efficacy and reduce the emergence of lamivudine resistance. Methods: In total, 36 consecutive anti-HBe positive patients were treated with interferon (3 MU subcutaneously three times weekly) and lamivudine (100 mg orally once a day) for 12 months. After completion of the combined treatment, all patients continued to receive lamivudine monotherapy indefinitely. Results: Overall, 35 patients (97%) showed virological response at 12 months. Four patients (11%) cleared HBsAg and developed anti-HBs. During the follow-up time, after the discontinuation of interferon, of 30 ± 12 months (range: 7–57 months), 13 patients (36%) exhibited breakthrough infection. The cumulative rates of breakthrough infection at the end of 1, 2, 3 and 4 years of treatment were 0%, 14%, 32%, and 59%, respectively. Conclusions: Combination therapy appears to be effective and may also delay the selection of lamivudine-resistant variants. However, controlled trials are definitely warranted to clarify the potential benefits of combination antiviral treatment over monotherapy. [ABSTRACT FROM AUTHOR]

Nikolaidis N, Vassiliadis T, Giouleme O, Tziomalos K, Grammatikos N, Patsiaoura K, Orfanou-Koumerkeridou E, Balaska A, Eugenidis N. Effect of lamivudine treatment in patients with decompensated cirrhosis due to anti-HBe positive/HBeAg-negative chronic hepatitis B.Clin Transplant 2005 DOI: 10.1111/j.1399-0012.2004.00340.x.© Blackwell Munksgaard, 2005Lamivudine has been shown to improve liver function and reduce the need for liver transplantation (LT) in patients with decompensated HBeAg-positive cirrhosis. Nevertheless, there is only limited experience with lamivudine in patients with anti-HBe-positive/HBeAg-negative cirrhosis. The primary aim of this study was to determine whether lamivudine treatment improves liver function and subsequently pre-LT survival or delays or obviates the need for LT in patients with anti-HBe-positive/HBeAg-negative cirrhosis. Between July 1998 and June 2003, 20 consecutive patients awaiting LT were enrolled in the study. All patients showed active viral replication and were treated with lamivudine 100 mg daily. Significant clinical improvement, defined as a decrease in the Child–Pugh–Turcotte score by≥2 points, was observed in 11 (55%) patients. The median change in the Child–Pugh–Turcotte score was−2 (range−5 to +2). The median time required to achieve a 2-point or greater reduction in Child–Pugh–Turcotte score was 6 months (range 3–12 months). In nine patients (45%), the Child–Pugh–Turcotte score decreased to≤6 (Child's class A cirrhosis). At last follow-up, 14 (70%) patients were alive and waiting for LT, with a median LT-free survival of 36 months (range 12–63 months). One patient (5%) developed resistance to lamivudine with reappearance of HBV DNA after 48 months of treatment. In conclusion, our results provide further evidence to the notion that lamivudine is beneficial in patients with decompensated anti-HBe-positive/HBeAg-negative cirrhosis caused by actively replicating chronic hepatitis B. [ABSTRACT FROM AUTHOR]