Cost-Effective Architectures for RC5 Brute Force Cracking

In this paper, we discuss the options for brute-force cracking of the RC5 block cipher, that is, for revealing the unknown secret key, given a sample ciphertext and a portion of the corresponding plaintext. First, we summarize the methods employed by the current cracking efforts. Then, we present two hardware architectures for finding the secret key using the “brute force” method. We implement the hardware in FPGA and ASIC and, based on the results, we discuss the cost and time needed to crack the cipher using today’s technology and suggest a minimum key length that can be considered secure.

Reductive Evolution of the Mitochondrial Processing Peptidases of the Unicellular Parasites Trichomonas vaginalis and Giardia intestinalis

Mitochondrial processing peptidases are heterodimeric enzymes (α/βMPP) that play an essential role in mitochondrial biogenesis by recognizing and cleaving the targeting presequences of nuclear-encoded mitochondrial proteins. The two subunits are paralogues that probably evolved by duplication of a gene for a monomeric metallopeptidase from the endosymbiotic ancestor of mitochondria. Here, we characterize the MPP-like proteins from two important human parasites that contain highly reduced versions of mitochondria, the mitosomes of Giardia intestinalis and the hydrogenosomes of Trichomonas vaginalis. Our biochemical characterization of recombinant proteins showed that, contrary to a recent report, the Trichomonas processing peptidase functions efficiently as an α/β heterodimer. By contrast, and so far uniquely among eukaryotes, the Giardia processing peptidase functions as a monomer comprising a single βMPP-like catalytic subunit. The structure and surface charge distribution of the Giardia processing peptidase predicted from a 3-D protein model appear to have co-evolved with the properties of Giardia mitosomal targeting sequences, which, unlike classic mitochondrial targeting signals, are typically short and impoverished in positively charged residues. The majority of hydrogenosomal presequences resemble those of mitosomes, but longer, positively charged mitochondrial-type presequences were also identified, consistent with the retention of the Trichomonas αMPP-like subunit. Our computational and experimental/functional analyses reveal that the divergent processing peptidases of Giardia mitosomes and Trichomonas hydrogenosomes evolved from the same ancestral heterodimeric α/βMPP metallopeptidase as did the classic mitochondrial enzyme. The unique monomeric structure of the Giardia enzyme, and the co-evolving properties of the Giardia enzyme and substrate, provide a compelling example of the power of reductive evolution to shape parasite biology

Technological Processing of Dried Powdered Rosehips to Tablets Through Wet Granulation

The pseudo-fruits of Dog Rose are a rich source of L-ascorbic acid and several other active substances, which means their high supportive therapeutic potential. The study aimed to examine the impact of the chosen technological procedure for the preparation of tablets containing rosehip powder on the amount of L-ascorbic acid in the final pharmaceutical form. Drying of the plant drug was performed at room temperature to avoid possible thermal degradation of this heat-sensitive compound. Similarly, drying of the granules after wet granulation in the oven was replaced by natural drying at room temperature. The composition of two types of prepared granule formulations differed in the filler – lactose (LAC) or microcrystalline cellulose (MCC). Apart from the disintegration test, they meet the technological requirements for granules or tablets. Lactose was confirmed as a more suitable filler, which despite the unsuccessful disintegration of the granules, ensures the disintegration of tablets within 15 minutes even without the addition of a special excipient acting as a disintegrant. The content of L-ascorbic acid detected using isotachophoresis – capillary zone electrophoresis was 87.16 ± 5.06 µg in LAC tablets and 63.33 ± 2.83 µg in MCC tablets

The role of pictures and gestures as a support mechanism for novel word learning: A training study with 2-year-old children

A training study examined novel word learning in 2-year-old children and assessed two nonverbal mechanisms, pictures and gestures, which are commonly used as communication support. The aim was to (1) compare these two support mechanisms and measure their effects on expressive word learning and (2) to investigate these effects on word production over an extended time period. At baseline, the children’s performance was assessed on vocabulary and grammatical skills, and the groups were matched on these key variables. Eighteen participants were taught novel words either accompanied by a gesture or by a picture. The training consisted of four 20-minute sessions per week over a period of four weeks. Following training, the children were assessed on their ability to produce novel words at three time points: immediately after training, at a 2-week follow-up and at a 6-week follow-up. Gesture training supported word learning significantly better than picture training across all three testing points. Children in both groups showed the best production immediately after training, with a small but nonsignificant decline at 2-week follow-up. There was a significant decline in time 3 compared to time 1, but the children were still able to produce 6.8 out of 10 novel words, suggesting long-term learning. Our findings suggest that gesture may be used to support word learning and could benefit children with late emerging language. The importance of these findings for language development and language intervention are discussed. <br/