New universality class for the fragmentation of plastic materials

We present an experimental and theoretical study of the fragmentation of polymeric materials by impacting polypropylene particles of spherical shape against a hard wall. Experiments reveal a power law mass distribution of fragments with an exponent close to 1.2, which is significantly different from the known exponents of three-dimensional bulk materials. A 3D discrete element model is introduced which reproduces both the large permanent deformation of the polymer during impact, and the novel value of the mass distribution exponent. We demonstrate that the dominance of shear in the crack formation and the plastic response of the material are the key features which give rise to the emergence of the novel universality class of fragmentation phenomena.Comment: 4 pages, 4 figures, appearing in Phys. Rev. Let

Downregulation of Tumor Necrosis Factor Expression in the Human Mono-Mac-6 Cell Line

Mono-Mac-6 cells, but not U937 cells, can be Induced to rapidly express tumor necrosis factor (TNF) mRNA and protein when triggered with Ilpopolysaccharlde (LPS) at 1 pg/mI. Preincubatlon of the cells for 3 d with low amounts of LPS (10 ng/mI) results In nearly complete suppression of TNF secretion. This downreguiatlon appears to occur at the pretranslational level since specIfIc mRNA is virtually undetectable under these conditions. By contrast, the same prelncubatlon with 10 ng/mI LPS results in enhanced phagocytosls (28.6-67.2% for Staphylococcus aureus), demonstrating that not all monocyte functions are suppressed. While these results show that only stringent exclusion of LPS from culture media allows for Induction of TNF In the Mono-Mac-6 cell line, the pronounced effect of LPS preincubatlon may also provide a suitable model with which to study the mechanisms of LPS-lnduced desensitizatIon

Formal Security Analysis and Performance Evaluation of the Linkable Anonymous Access Protocol

Part 2: The 2014 Asian Conference on Availability, Reliability and Security, AsiaARES 2014International audienceThe introduction of e-Health applications has not only brought benefits, but also raised serious concerns regarding security and privacy of health data. The increasing demands of accessing health data, highlighted critical questions and challenges concerning the confidentiality of electronic patient records and the efficiency of accessing these records. Therefore, the aim of this paper is to provide secure and efficient access to electronic patient records. In this paper, we propose a novel protocol called the Linkable Anonymous Access protocol (LAA). We formally verify and analyse the protocol against security properties such as secrecy and authentication using the Casper/FDR2 verification tool. In addition, we have implemented the protocol using the Java technology to evaluate its performance. Our formal security analysis and performance evaluation proved that the LAA protocol supports secure access to electronic patient records without compromising performance

Template-based Fault Injection Analysis of Block Ciphers

We present the first template-based fault injection analysis of FPGA-based block cipher implementations. While template attacks have been a popular form of side-channel analysis in the cryptographic literature, the use of templates in the context of fault attacks has not yet been explored to the best of our knowledge. Our approach involves two phases. The first phase is a profiling phase where we build templates of the fault behavior of a cryptographic device for different secret key segments under different fault injection intensities. This is followed by a matching phase where we match the observed fault behavior of an identical but black-box device with the pre-built templates to retrieve the secret key. We present a generic treatment of our template-based fault attack approach for SPN block ciphers, and illustrate the same with case studies on a Xilinx Spartan-6 FPGA-based implementation of AES-128

The relationships of markers of cholesterol homeostasis with carotid intima-media thickness

Background: The relationship of cholesterol homeostasis and carotid intima-media thickness (cIMT) is unknown. To address this, we assessed markers of cholesterol homeostasis (serum plant sterols and cholesterol precursor concentrations as surrogate measures of cholesterol absorption and synthesis, respectively) and cIMT in a middle-aged, statin-naive population. Methods: In this prospective study of primary prevention cIMT was measured by ultrasound in 583 hospital employees aged 25—60 years without prevalent cardiovascular disease or lipid-modifying medication. The serum concentrations of plant sterols (as markers of cholesterol absorption) were measured by gas-liquid chromatography. Lathosterol serum concentrations were quantitated to assess hepatic cholesterol synthesis. Results: cIMT correlated positively with serum cholesterol (r = 0.22, P,0.0005) and lathosterol-to-cholesterol (r = 0.18, P,0.001). In contrast, plant sterols, as markers of cholesterol absorption, showed a weak negative correlation to cIMT measurements (r =20.18; P,0.001 for campesterol-to-cholesterol). Stratifying subjects by serum sterol levels, we found that cIMT increased continuously over quintiles of serum cholesterol (P,0.0005) and was positively associated to serum lathosterol-to-cholesterol levels (P=0.007), on the other hand, plant sterol levels showed a weak negative association to cIMT (P,0.001 for campesterol-to-cholesterol). Conclusions: In this population without prevalent cardiovascular diseases or lipid-modifying medication, markers of increased endogenous cholesterol synthesis correlated positively with cIMT, while markers of cholesterol absorption showed a weakly negative correlation. These data suggest that not only total serum cholesterol levels but also differences in cholesterol homeostasis are associated with cIMT

Essential Roles for Soluble Virion-Associated Heparan Sulfonated Proteoglycans and Growth Factors in Human Papillomavirus Infections

A subset of human papillomavirus (HPV) infections is causally related to the development of human epithelial tumors and cancers. Like a number of pathogens, HPV entry into target cells is initiated by first binding to heparan sulfonated proteoglycan (HSPG) cell surface attachment factors. The virus must then move to distinct secondary receptors, which are responsible for particle internalization. Despite intensive investigation, the mechanism of HPV movement to and the nature of the secondary receptors have been unclear. We report that HPV16 particles are not liberated from bound HSPG attachment factors by dissociation, but rather are released by a process previously unreported for pathogen-host cell interactions. Virus particles reside in infectious soluble high molecular weight complexes with HSPG, including syndecan-1 and bioactive compounds, like growth factors. Matrix mellatoproteinase inhibitors that block HSPG and virus release from cells interfere with virus infection. Employing a co-culture assay, we demonstrate HPV associated with soluble HSPG-growth factor complexes can infect cells lacking HSPG. Interaction of HPV-HSPG-growth factor complexes with growth factor receptors leads to rapid activation of signaling pathways important for infection, whereas a variety of growth factor receptor inhibitors impede virus-induced signaling and infection. Depletion of syndecan-1 or epidermal growth factor and removal of serum factors reduce infection, while replenishment of growth factors restores infection. Our findings support an infection model whereby HPV usurps normal host mechanisms for presenting growth factors to cells via soluble HSPG complexes as a novel method for interacting with entry receptors independent of direct virus-cell receptor interactions