Doubly Perfect Nonlinear Boolean Permutations

Due to implementation constraints the XOR operation is widely used in order to combine plaintext and key bit-strings in secret-key block ciphers. This choice directly induces the classical version of the differential attack by the use of XOR-kind differences. While very natural, there are many alternatives to the XOR. Each of them inducing a new form for its corresponding differential attack (using the appropriate notion of difference) and therefore block-ciphers need to use S-boxes that are resistant against these nonstandard differential cryptanalysis. In this contribution we study the functions that offer the best resistance against a differential attack based on a finite field multiplication. We also show that in some particular cases, there are robust permutations which offers the best resistant against both multiplication and exponentiation base differential attacks. We call them doubly perfect nonlinear permutations

Relations between topography, wetlands, vegetation cover and stream water chemistry in boreal headwater catchments in Sweden

International audienceA large part of the spatial variation of stream water chemistry is found in headwater streams and small catchments. To understand the dominant processes, taking place in small and heterogeneous catchments, spatial and temporal data with high resolution is needed. In most cases available map data has too low quality and resolution to successfully be used in environmental assessments and modelling. In this study 18 forested catchments (1?4 km2) were selected within a 120×50 km area in the county of Värmland in western Sweden. The aim was to test if topographic and vegetation variables derived from official datasets were correlated to stream water chemistry, represented by DOC, Al, Fe and Si content. A GIS was used to analyse the elevation characteristics, generate topographic indices and calculate the percentage of wetlands and a number of vegetation classes. The results clearly show that the topography has a major influence on the occurrence of wetlands, which has a major influence on stream water chemistry. There were very strong correlations between mean slope and percentage wetland, percentage wetland and DOC, mean slope and DOC and mean topographic wetness index and DOC. The conclusion was that official topographic data, despite uncertain or low quality and resolution, could be useful in the prediction of headwater chemistry in boreal forested catchments

TOWARD A SOCIAL PSYCHOLOGY OF FOOD USE

This paper focuses on the social construction offood use patterns through the dialectical moments of externalisation, objectiuation, and internalization. The major emphasis is on the situational, intersubjective, and symbolic dimensions of food use which have most often been overlooked by normative programs and research. Also, the point is made that there is great diversity in food use patterns across groups and cultures and each is based upon different logic by which food use is organized. The "basic four" logic popular in middle-class America is not the food logic, but a food logic

Extension of nano-confined DNA: quantitative comparison between experiment and theory

The extension of DNA confined to nanochannels has been studied intensively and in detail. Yet quantitative comparisons between experiments and model calculations are difficult because most theoretical predictions involve undetermined prefactors, and because the model parameters (contour length, Kuhn length, effective width) are difficult to compute reliably, leading to substantial uncertainties. Here we use a recent asymptotically exact theory for the DNA extension in the "extended de Gennes regime" that allows us to compare experimental results with theory. For this purpose we performed new experiments, measuring the mean DNA extension and its standard deviation while varying the channel geometry, dye intercalation ratio, and ionic buffer strength. The experimental results agree very well with theory at high ionic strengths, indicating that the model parameters are reliable. At low ionic strengths the agreement is less good. We discuss possible reasons. Our approach allows, in principle, to measure the Kuhn length and effective width of a single DNA molecule and more generally of semiflexible polymers in solution.Comment: Revised version, 6 pages, 2 figures, 1 table, supplementary materia

Developing an enhanced 7-color multiplex IHC protocol to dissect immune infiltration in human cancers.

The TSA Opal multiplex immunohistochemistry (mIHC) protocol (PerkinElmer) has been used to characterize immune infiltration in human cancers. This technique allows multiple biomarkers to be simultaneously stained in a single tissue section, which helps to elucidate the spatial relationship among individual cell types. We developed and optimized two improved mIHC protocols for a 7-color panel containing 6 biomarkers (CD3, CD8, CD163, PD-L1, FoxP3, and cytokeratin (CK)) and DAPI. The only difference between these two protocols was the staining sequence of those 6 biomarkers as the first sequence is PD-L1/CD163/CD8/CK/CD3/FoxP3/DAPI and the second sequence is FoxP3/CD163/CD8/CK/CD3/PD-L1/DAPI. By comparing PD-L1/FoxP3 staining in mIHC and singleplex PD-L1/FoxP3 staining on the adjacent slide, we demonstrated that the staining sequence does not affect the staining intensity of individual biomarkers as long as a proper antigen retrieval method was used. Our study suggests that use of an antigen retrieval buffer with higher pH value (such as Tris-EDTA pH9.0) than that of the stripping buffers (such as citrate buffer pH6.0) is helpful when using this advanced mIHC method to develop panels with multiple biomarkers. Otherwise, individual biomarkers may exhibit different intensities when the staining sequence is changed. By using this protocol, we characterized immune infiltration and PD-L1 expression in head and neck squamous cell carcinoma (HNSCC), breast cancer (BCa), and non-small cell lung cancer (NSCLC) specimens. We observed a statistically significant increase in CD3+ cell populations within the stroma of NSCLC as compared to BCa and increased PD-L1+ tumor cells in HNSCC as opposed to BCa