An Algebraic Detection Approach for Control Systems under Multiple Stochastic Cyber-attacks

In order to compromise a target control system successfully, hackers possibly attempt to launch multiple cyberattacks aiming at multiple communication channels of the control system. However, the problem of detecting multiple cyber-attacks has been hardly investigated so far. Therefore, this paper deals with the detection of multiple stochastic cyber-attacks aiming at multiple communication channels of a control system. Our goal is to design a detector for the control system under multiple cyberattacks. Based on frequency-domain transformation technique and auxiliary detection tools, an algebraic detection approach is proposed. By applying the presented approach, residual information caused by different attacks is obtained respectively and anomalies in the control system are detected. Sufficient and necessary conditions guaranteeing the detectability of the multiple stochastic cyber-attacks are obtained. The presented detection approach is simple and straightforward. Finally, two simulation examples are provided, and the simulation results show that the detection approach is effective and feasible.      

Trichoderma-Derived Pentapeptides from the Infected Nest Mycobiome of the Subterranean Termite Coptotermes testaceus

Termites live in a dynamic environment where colony health is strongly influenced by surrounding microbes. However, little is known about the mycobiomes of lower termites and their nests, and how these change in response to disease. Here we compared the individual and nest mycobiomes of a healthy subterranean termite colony (Coptotermes testaceus) to one infected and ultimately eradicated by a fungal pathogen. We identified Trichoderma species in the materials of both nests, but they were also abundant in the infected termites. Methanolic extracts of Trichoderma sp. FHG000531, isolated from the infected nest, were screened for secondary metabolites by UHPLC-HR MS/MS-guided molecular networking. We identified many bioactive compounds with potential roles in the eradication of the infected colony, as well as a cluster of six unknown peptides. The novel peptide FE011 was isolated and characterized by NMR spectroscopy. The function of this novel peptide family as well as the role of Trichoderma species in dying termite colonies therefore requires further investigation.     

High temperature creep-mediated functionality in polycrystalline barium titanate

Dislocations in oxides can be described as charged line defects and means for one-dimensional doping, which can tune electrical and thermal properties. Furthermore, theoretically it was shown that dislocations can pin ferroelectric domain walls. Broader application of this concept hinges on the development of a methodology to avail this approach to polycrystalline ceramics. To this end, we use different creep mechanisms as a method to introduce multidimensional defects and quantify structural changes. A deformation map for fine-grained barium titanate is provided and the influences of the defects and creep regimes are correlated in this first study to modifications of electrical conductivity, dielectric, ferroelectric, and piezoelectric properties. A plastic deformation of 1.29% resulted in an increase in the Curie temperature by 5°C and a decrease in electromechanical strain by 30%, pointing toward electromechanical hardening by dislocations.     

The HüGaProp-Container: Analytical Infrastructure for the Carbon2Chem® Challenge

The utilization of industrial off-gases as raw material requires a detailed knowledge on their time-depending composition, especially with regard to trace components. Within the framework of the HüGaProp project (Hüttengas Properties) a measuring container and the analytical methods for the characterization of trace components in the three raw metallurgical gases was developed. The mobile container is deployed in the project Carbon2Chem® to characterize the available off-gases at a steel mill and provide fundamental data to determine the required gas cleaning as well as the background for the further process design.     

Modulation of Pharmacologically Relevant Properties of Piperidine Derivatives by Functional Groups in an Equatorial or Axial β-Position to the Amino Group

Thirteen epimeric pairs of 5-substituted N-piperonyl-3-phenylpiperidine derivatives were synthesized in order to explore the stereospecific modulation of basicity, lipophilicity, aqueous solubility, and membrane permeation by functional groups in equatorial or axial positions beta to the amine unit. While this comprehensive data set provides enhanced insight into multiple factors that affect basicity and lipophilicity, it fills an important knowledge gap, providing a frame of reference for the property-based design of bioactive compounds. Impacts on amine basicity are very pronounced for the β-equatorial functional groups and parallel basicity-lowering effects known for acyclic amine derivatives. For β-axial functional groups, the basicity-lowering effects are generally decreased, with the nitrile group as the only exception. Basicity and lipophilicity modulations observed for β-axial functional groups are quite diverse and rationalized in terms of intramolecular hydrogen bonding, dipolar interactions, and special solvation effects. Aqueous solubility and (artificial) membrane permeability are discussed with reference to lipophilicity.     

Halogenation-Guided Chemical Screening Provides Insight into Tjipanazole Biosynthesis by the Cyanobacterium Fischerella ambigua

Halogenated natural products (HNPs) show a wide range of interesting biological activities. Chemistry-guided screening with a software tool dedicated to identifying halogenated compounds in HPLC-MS data indicated the presence of several uncharacterised HNPs in an extract of the cyanobacterium Fischerella ambigua (Näg.) Gomont 108b. Three new natural products, tjipanazoles K, L, and M, were isolated from this strain together with the known tjipanazoles D and I. Taking into account the structures of all tjipanazole derivatives detected in this strain, reanalysis of the tjipanazole biosynthetic gene cluster allowed us to propose a biosynthetic pathway for the tjipanazoles. As the isolated tjipanazoles show structural similarity to arcyriaflavin A, an inhibitor of the clinically relevant multidrug-transporter ABCG2 overexpressed by different cancer cell lines, the isolated compounds were tested for ABCG2 inhibitory activity. Only tjipanazole K showed appreciable transporter inhibition, whereas the compounds lacking the pyrrolo[3,4-c] ring or featuring additional chloro substituents were found to be much less active.     

The Structural Origins of Wood Cell Wall Toughness

The remarkable mechanical stability of wood is primarily attributed to the hierarchical fibrous arrangement of the polymeric components. While the mechanisms by which fibrous cell structure and cellulose microfibril arrangements lend stiffness and strength to wood have been intensively studied, the structural origins of the relatively high splitting fracture toughness remain unclear. This study relates cellulose microfibril arrangements to splitting fracture toughness in pine wood cell walls using in situ electron microscopy and reveals a previously unknown toughening mechanism: the specific arrangement of cellulose microfibrils in the cell wall deflects cracks from the S2 layer to the S1/S2 interface, and, once there, causes the crack to be repetitively arrested and shunted along the interface in a zig-zag path. It is suggested that this natural adaptation of wood to achieve tough interfaces and then deflect and trap cracks at them can be generalized to provide design guidelines to improve toughness of high-performance and renewable engineering materials.