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Popular Blockchain-based cryptocurrencies, like Bitcoin, are increasingly being used maliciously for illegal trades. In order to trace and analyze suspected Bitcoin transactions and addresses, address clustering methods and Bitcoin flow analysis methods are gaining attention recently. However, existing methods only focus on Bitcoin addresses and flow, and neglect other important information, such as transaction structure and behavior features. In order to exploit all useful features of transactions, this paper proposes a Bitcoin transaction network analytic method for facilitating Blockchain forensic investigation based on an extended safe Petri Net. The structural features and dynamic semantics of Petri net are used in our proposed model to define the static and dynamic features of Bitcoin transactions. Nineteen features have been identified to define Bitcoin transaction patterns for analyzing and finding suspected addresses. Bitcoin gene has been embedded into the Petri net transitions to trace and analyze Bitcoin flow accurately. Finally, marginal distribution analysis of Bitcoin transaction features and data visualization techniques are used to eliminate some false positive samples further and to improve the accuracy of identifying suspected addresses. The proposed Bitcoin transaction network analytic method provides a reliable forensic investigation model along with a prototype platform which is beneficial for financial security. The efficiency of our proposed method is empirically verified based on a real-life case study analysis.

A series of new fungicides that can inhibit the succinate dehydrogenase (SDH) was classified and named as SDH inhibitors by the Fungicide Resistance Action Committee in 2009. To develop more potential SDH inhibitors, we designed and synthesized a novel series of N-(substituted pyridine-4-yl)-1-(substituted phenyl)-5-trifluoromethyl-1H-pyrazole-4-carboxamide derivatives, 4a-4i, namely, 5a-5h, 6a-6h, and 7a-7j. The bioassay results demonstrated that some title compounds exhibited excellent antifungal activity against four tested phytopathogenic fungi (Gibberella zea, Fusarium oxysporum, Cytospora mandshurica, and Phytophthora infestans). The EC50 values were 1.8 μg/mL for 7a against G. zeae, 1.5 and 3.6 μg/mL for 7c against F. oxysporum and C. mandshurica, respectively, and 6.8 μg/mL for 7f against P. infestans. The SDH enzymatic activity testing revealed that the IC50 values of 4c, 5f, 7f, and penthiopyrad were 12.5, 135.3, 6.9, and 223.9 μg/mL, respectively. The molecular docking results of this series of title compounds with SDH model demonstrated that the compounds could completely locate inside of the pocket, the body fragment formed H bonds, and the phenyl ring showed a π-π interaction with Arg59, suggesting that these novel 5-trifluoromethyl-pyrazole-4-carboxamide derivatives might target SDH. These results could provide a benchmark for understanding the antifungal activity against the phytopathogenic fungus P. infestans and prompt us to discover more potent SDH inhibitors.

We evaluated the thermochemical properties and suitability of a variety of lignocellulosic biomass residues in Pakistan for energy production. Proximate, ultimate and calorific value analyses were performed to know the energy perspective, whereas thermogravimetric analysis was used to study the decomposition behavior of biomass samples under pyrolysis conditions. The moisture content, volatile matter, fixed carbon and ash content in the biomass samples were found within the range of 4.38–5.69%, 63.25–80.53%, 7.97–23.13%, and 7.12–14.35%, respectively. The range of carbon, hydrogen, and oxygen content was reported as 35.83–47.23%, 5.2–6.56%, and 45.6–58.55%, respectively. Lower values of sulfur and nitrogen content amongst the samples indicated that the biomass was environmentally friendly in terms of energy production. The heating value of the biomass was reported in the range of 15.20–18.44 MJ/kg. Fourier transform infrared spectroscopy showed the existence of hydroxyl, aldehydes, ketones, aromatic compounds, carbonyl compounds, ether, and halogen groups. Orange leaf biomass indicated a greater potential in producing bio-oil, whereas the horticulture biomass and mango leaves may have greater potential for biochar.

It is a considerable challenge for the phase behavior of chemical separation industry to correlate and predict the vapor–liquid equilibria (VLE) data of the binary and ternary systems containing as...

A series of new fungicides that can inhibit the succinate dehydrogenase (SDH) was classified and named as SDH inhibitors by the Fungicide Resistance Action Committee in 2009. To develop more potential SDH inhibitors, we designed and synthesized a novel series of

Nowadays, theoretical calculations are playing a pivotal role in understanding the underlying reaction mechanism and at the same time used for exploration of the zeolite-based catalysts. For such systems, an inconsistency is seen in formulating the active site and choosing the size of the zeolite framework. Herein, we have formulated the standard theoretical model for the MFI-based catalytic systems considering the most recent experimental findings.[1] The formulated model is used for the explanation of the mechanism of acetic acid formation by the co-activation of CO

The reaction mechanism and origin of asymmetric induction for conjugate addition of cyanide to the C=C bond of olefin were investigated at the B3LYP-D3(BJ)/6-31+G**//B3LYP-D3(BJ)/6-31G**(SMD, toluene) theoretical level. The release of HCN from the reaction of ethyl cyanoformate (CNCOOEt) and isopropanol (HOiPr) was catalyzed by cinchona alkaloid catalyst. The cyanation reaction of olefin proceeded through a two-step mechanism, in which the C-C bond construction was followed by H-transfer to generate a cyanide adduct. For non-catalytic reaction, the activation barrier for the rate-determining C-H bond construction step was 34.2 kcal mol&minus, 1, via a four-membered transition state. The self-assembly Ti(IV)-catalyst from tetraisopropyl titanate, (R)-3,3&prime, disubstituted biphenol, and cinchonidine accelerated the addition of cyanide to the C=C double bond by a dual activation process, in which titanium cation acted as a Lewis acid to activate the olefin and HNC was orientated by hydrogen bonding. The steric repulsion between the 9-phenanthryl at the 3,3&prime, position in the biphenol ligand and the Ph group in olefin raised the Pauli energy (&Delta, E&ne, Pauli) of reacting fragments at the re-face attack transition state, leading to the predominant R-product.

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The antioxidant activities of 18 typical phenolic acids were investigated using 2, 2′-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. Five thermodynamic parameters involving hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton-loss electron transfer (SPLET) mechanisms were calculated using density functional theory with the B3LYP/UB3LYP functional and 6–311++G (d, p) basis set and compared in the phenolic acids. Based on the same substituents on the benzene ring, -CH2COOH and -CH = CHCOOH can enhance the antioxidant activities of phenolic acids, compared with -COOH. Methoxyl (-OCH3) and phenolic hydroxyl (-OH) groups can also promote the antioxidant activities of phenolic acids. These results relate to the O-H bond dissociation enthalpy of the phenolic hydroxyl group in phenolic acids and the values of proton affinity and electron transfer enthalpy (ETE) involved in the electron donation ability of functional groups. In addition, we speculated that HAT, SET-PT, and SPLET mechanisms may occur in the DPPH reaction system. Whereas SPLET was the main reaction mechanism in the FRAP system, because, except for 4-hydroxyphenyl acid, the ETE values of the phenolic acids in water were consistent with the experimental results.

Programming Languages are core courses in computer science and computing-related disciplines, and there are increasing demands on improving the experiences, motivation and efficiency of programming language teaching and learning. In recent decades, online judge (OJ) systems have been popularly adopted in educational environments to support real-time learning feedback, and provide interactive programming practice. However, most existing OJ systems rely on significant resource for hardware virtualization, and suffer from long development cycles and extensive maintenances. This paper proposed a course-oriented OJ system based on the Docker Container techniques to significantly reduce the cost and maintenance of deployment of existing OJ system. The proposed approach is designed in the form of an experimental system, which is effective in stimulating the students to learn programming language and assist the instant assessment of coursework. Meanwhile, our proposed system can be integrated with major massive open online course (MOOC) systems for assessment. The efficiency and performance of our proposed system has been evaluated and tested by 1460 students in Nanyang Institute of Technology during term time between 2018 and 2019.

Internet of Things (IoT) is on the raise and has become an integral part of our daily activities. Cloud Computing has been serving as an effective platform to IoT application that host data execution at the back-end server at the datacentres. The extent of IoT to mission critical delay intolerant applications require immediate responses from the providers. While the traditional Cloud infrastructure incurs unavoidable process delays, Fog Computing can effectively mitigate such delays to serve latency sensitive applications with reduced energy consumption. However, the success of the Fog architecture relies on effective data management both during transmission and execution. To this end, this paper discusses the advantages of Fog computing over Clouds in addressing energy and time constraints of IoT application, uncovers the challenges faced by data aggregation in Fog computing. An important contribution of this paper is the review on the data aggregation strategies and a recommended hybrid data aggregation scheme for Fog based IoT applications.

Nowadays, theoretical calculations are playing a pivotal role in understanding the underlying reaction mechanism and at the same time used for exploration of the zeolite-based catalysts. For such systems, an inconsistency is seen in formulating the active site and choosing the size of the zeolite framework. Herein, we have formulated the standard theoretical model for the MFI-based catalytic systems considering the most recent experimental findings.[1] The formulated model is used for the explanation of the mechanism of acetic acid formation by the co-activation of CO2 and CH4 over the MFI based catalyst, which excellently justifies the experimental results. The following conclusions are drawn from the work, a sufficiently large zeolite framework is critical to validate the experimental findings. The extended zeolite framework is crucial for accurate optimization of the active site, drawing the plausible mechanisms and predicting the correct rate-limiting step of the reaction. Moreover, the neighbor Al-Al atoms must be kept away from each other by at-least two Si-centers to be consistent with the experiment.

The UV–vis absorption spectra and hyperpolarizability of a series of substituted dihydroazulenes (DHAs) and vinylheptafulvenes (VHFs) photochrome are studied at B3LYP/6-31G(d,p) level of theory. Electronic properties strongly depended on the nature and position of substituents on DHA-VHF photoswitch. Electron withdrawing groups (NO 2 , CHO) and halogens at position 8a of DHA cause red shift of the λ max , whereas blue shift of λ max was observed when these functional groups were present at positions 8, 7, 5 and 4. Mesomerically electron donating groups (NH 2 , OH, and SH) on DHA cause hypsochromic shift of the λ max except amino and thiol at positions 4 and 6 (Red shift of λ max ). The absorptions maximum of VHF, on the other hand, was red shifted for any functionalization at the seven membered ring of VHF. The maximum red shift of λ max (VHF) was observed for substituents at positions 8a, followed by position 6 and 4. Electron donating substituents are very effective at decreasing the spectral overlap of DHA and VHF. In general, hyperpolarizabilities of VHFs are higher than their corresponding DHAs. For electron withdrawing groups, the largest β (8.80 esu) was obtained for DHA bearing NO 2 at position 6. Among electron donors, NH 2 substituted DHAs showed the higher β values compared to the molecules bearing OH and CH 3 . For VHF, the highest value of β (16.58 esu) was observed for molecule bearing bromine at position 6.

Thermal cyclization for a series of substituted vinylheptafulvenes (VHFs) to dihydroazulenes (DHAs) was studied at PBE0 method of density functional theory in the gas phase and in the acetonitrile solvent (through PCM). Judicious control of the thermal reaction through substituent is quite necessary to design thermally robust DHA–VHF photoswitches. For most of the substituents, DHA was predicted thermodynamically stable over VHF except for amino (in gas phase and solvent) and hydroxyl (in acetonitrile), where DHA isomers were calculated thermally unstable compared to VHF. Activation barriers for thermal electrocyclic reaction in both media showed positive correlation with Taft’s σ R values at positions 7 and 5, however, a negative correlation was observed at position 4 and 6. The latter unprecedented behavior is proposed to arise from the delocalization of negative charges on the seven membered ring. Activation barriers for amino-substituted VHFs were generally lower than expected from Taft’s σ R. A fluoro group at the position 7 was quite effective in imparting very high activation barrier (31.73 kcal mol−1) for the thermal cyclization in the gas phase. However, in the acetonitrile solvent, the highest activation barriers were observed for electron withdrawing CHO (28.10 kcal mol−1) and NO2 (28.13 kcal mol−1) groups at positions 7.