Most existing Android malware detection and categorization techniques are static approaches, which suffer from evasion attacks, such as obfuscation. By analyzing program behaviors, dynamic approaches ...are potentially more resilient against these attacks. Yet existing dynamic approaches mostly rely on characterizing system calls which are subject to system-call obfuscation. This paper presents DroidCat, a novel dynamic app classification technique, to complement existing approaches. By using a diverse set of dynamic features based on method calls and inter-component communication (ICC) Intents without involving permission, app resources, or system calls while fully handling reflection, DroidCat achieves superior robustness than static approaches as well as dynamic approaches relying on system calls. The features were distilled from a behavioral characterization study of benign versus malicious apps. Through three complementary evaluation studies with 34 343 apps from various sources and spanning the past nine years, we demonstrated the stability of DroidCat in achieving high classification performance and superior accuracy compared with the two state-of-the-art peer techniques that represent both static and dynamic approaches. Overall, DroidCat achieved 97% F1-measure accuracy consistently for classifying apps evolving over the nine years, detecting or categorizing malware, 16%-27% higher than any of the two baselines compared. Furthermore, our experiments with obfuscated benchmarks confirmed higher robustness of DroidCat over these baseline techniques. We also investigated the effects of various design decisions on DroidCat's effectiveness and the most important features for our dynamic classification. We found that features capturing app execution structure such as the distribution of method calls over user code and libraries are much more important than typical security features such as sensitive flows.
•CT prior to HMT was an effective method for preparing RS with thermal stability.•The endothermic and crystalline peaks of starch samples disappeared after CT-HMT.•The esterification reaction became ...stronger during HMT according to FT-IR analysis.•Raman spectroscopy presented similar structural property results with XRD and FT-IR.•The hydrolysis kinetic parameters of starch (C∞ and k) reduced after CT-HMT.
In this study, wheat starch, A- and B-type starch granules were firstly treated with citric acid (CT) and then subjected to heat-moisture treatment (HMT). The maximum thermo-stable resistant starch (RS) contents reached 71.52%, 71.27%, 71.58% for CT-HMT wheat starch, A- and B-type starch granules, respectively. The hydrolysis kinetic parameters (C∞ and k) reduced after CT-HMT. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results revealed that the endothermic and crystalline peaks of CT-HMT starch samples disappeared. Scanning electron microscopy (SEM) results showed that more collapses and destructiveness appeared on the surfaces of CT-HMT starch granules. The esterification reaction became stronger during HMT according to Fourier transform-infrared (FT-IR) spectroscopy analysis, which was consistent with the results of degree of substitution. Raman spectroscopy presented similar structural properties results with XRD and FT-IR. These results suggest that CT prior to HMT is a useful method for preparing high amount of thermally stable RS.
•The spatial-temporal characteristics of carbon emissions are different for each land use type.•Construction land is the main source of carbon.•Carbon emissions in the Yellow River Delta were ...spatially clustered.•The distribution of carbon emissions is larger in the “east-west” than in the “north-south”.
Land use is a major source of anthropogenic carbon emissions and a driver of climate change, so it is necessary to explore the spatial and temporal distribution characteristics of carbon emissions from different land use types. Based on the land use type data and fossil energy consumption data in the same period, we analyzed the spatial and temporal distribution characteristics of carbon emissions in the Yellow River Delta from 2000 to 2019 by constructing a carbon emission model, carbon footprint and Moran’s I index. The empirical results show that total net carbon emissions in the Yellow River Delta increased from 3.1×1010kg to 1.5×1011kg during 2000–2019. Construction land is the main source of carbon, while forest land and water contribute more to the total carbon sink in the study area. Carbon emissions in the Yellow River Delta were spatially clustered, characterized by a larger distribution of carbon emissions in the “east-west” direction than in the “north-south” direction. The results of the study are conducive to a comprehensive understanding of the spatial distribution pattern of land use carbon sources/sinks in the Yellow River Delta, and provide a certain reference basis for the formulation of low-carbon economic policies in the region.
•Porous wheat starches were cross-linked with 4% sodium trimetaphosphate.•The solubility and swelling power of cross-linked starches decreased.•The thermal stability and adsorption capacities of ...cross-linked starches increased.•Adsorption behavior of 2-HWPS-C fitted Langmuir isotherm model.•Phosphate groups were bound to the OH groups on starches by covalent bond (COP).
In this study, effect of cross-linking with 4% sodium trimetaphosphate on the structural and adsorptive properties of porous wheat starches was investigated. The results showed that the cross-linked porous starches (CLPS) exhibited lower solubility, swelling power and ordered structure but higher thermal stability compared with the corresponding porous starches (PS). Cross-linking led to the formation of more dense holes on the surfaces of PS, as observed by SEM. XPS results demonstrated that phosphate groups were bound to the OH groups on starches by covalent bonds (COP). Adsorption experiments manifested that the CLPS exhibited higher adsorption capacities for water, oil and methylene blue compared to the corresponding PS. Furthermore, the isothermal data of the CLPS fitted the Langmuir isotherm model well compared to Freundich and Tempkin models, and the adsorption was exothermic and favorable. These results suggest that cross-linking modification can improve the thermal stability and adsorptive properties of PS.
•Wheat starch was treated with RHMT and then subjected to enzymatic hydrolysis.•The number of pores and adsorption capacities of dual-modified starches increased.•Adsorption behavior of APS and ...2-HAPS fitted Freundlich isotherm model.•Dual-modification increased specific surface area and total pore volume of starch.
Effects of the combination of repeated heat-moisture treatment for two times (2-HMT) and compound enzymes hydrolysis on structural and physicochemical properties of porous wheat starches were investigated. The dual-modification resulted in the formation of more pores on the surface of native starches, as revealed by SEM. Compared with single-modified starch samples, the porous starch samples treated by dual-modification exhibited higher gelatinization temperature, lower gelatinization enthalpy and higher crystallinity, as determined by DSC, FT-IR and XRD. Batch adsorption experiments manifested that the dual-modified starch samples exhibited higher adsorption capacities for water, oil and methylene blue. Moreover, the adsorption behaviors of the porous A-type starch granules with or without 2-HMT fitted Freundlich isotherm model well. Low-temperature nitrogen adsorption results showed that dual modifications greatly increased specific surface area and total pore volume of the starch samples. The present study suggests that the dual-modification is an attractive alternative for preparing porous wheat starches.
Facing increasingly serious environmental problems, technological innovation has become the key for industrial enterprises to coordinate energy conservation and emission reduction constraints and ...achieve steady growth of the industrial economy. Considering the impact of energy consumption and environmental pollution on the technological innovation efficiency of industrial enterprises, this paper incorporates industrial energy consumption, pollution control, and wastewater and exhaust emissions into the technical inefficiency equation. Based on the panel data of industrial enterprises in 30 provinces and autonomous regions in China from 2009 to 2016, the stochastic frontier analysis (SFA) model is used to study the effect of energy consumption and environmental pollution on technological innovation efficiency of industrial enterprises. The research results show that reducing energy consumption and increasing pollution treatment investment both have a significant driving effect on the improvement of industrial enterprises’ technological innovation efficiency. Industrial wastewater and exhaust emissions have the opposite effect; unreasonable input mode of pollution control and personnel allocation have hindered the improvement of industrial enterprises’ technological innovation efficiency. The average annual trend of technological innovation efficiency in industrial enterprises shows a curve of first rising, then falling, and rising again. The average values of Chongqing, Zhejiang, and Hunan rank in the top three, and the average values of Qinghai, Heilongjiang, and Inner Mongolia rank the bottom three. The average values of other provinces are higher than 0.9, and the difference is small. A suitable incentive mechanism should be established for industrial enterprises to save energy and reduce emissions and strengthen pollution control, improve the training program for environmental protection technical personnel, and provide important support for improving the green competitiveness of industrial enterprises.
•The ratio of α-1,6 glycosidic linkage of WS decreased after debranching and RHMT.•Raman and FT-IR confirmed more ordered structure of starch was formed after RHMT.•More agglomerates appeared on the ...surfaces of RHMT samples as revealed by SEM.•The thermal stability of PUL-WS sample was enhanced after RHMT.•The RS content increased and reached the maximum after RHMT for three times.
In this study, wheat starch (WS) was firstly debranched with pullulanase (PUL) and then subjected to repeated heat-moisture treatments (RHMT). The effects of PUL and RHMT on the structure, physicochemical properties and in vitro digestibility of WS were investigated. The proton nuclear magnetic resonance spectroscopy confirmed that the ratio of α-1,6 glycosidic linkage decreased. Raman and Fourier transform-infrared spectroscopy demonstrated that more ordered structure of starch was formed. Differential scanning calorimetry and X-ray diffraction analysis revealed that RHMT could enhance thermal stability and degree of crystal perfection of PUL-WS sample. Scanning electron microscopy results showed that more agglomerates appeared on the surfaces of RHMT starch granules. The swelling power and solubility significantly decreased after HMT. Additionally, the resistant starch (RS) content of RHMT samples significantly increased. These results suggest that debranching and RHMT can significantly change the physicochemical properties and digestibility of WS, and it’s beneficial to the RS formation.
Radical‐containing frameworks (RCFs) have emerged as promising functional materials in various fields due to the combination of the highly ordered frame structure and the fascinating property of ...organic radicals. Here, the first example of radical‐containing supramolecular organic frameworks (SOFs) fabricated by the chaotropic effect between closo‐dodecaborate cluster (B12H122−) and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine (TPT3+) is presented. The SOFs can be easily synthesized by stirring the B12H122− and the TPT3+ in aqueous solution through self‐assembly. Upon 435 nm light irradiation, the SOFs exhibits photochromic behavior from slight yellow (SOF‐1) to dark purple (SOF‐2). Electron paramagnetic resonance spectroscopy also reveals that stable radicals are generated in situ after light irradiation. Powder X‐ray diffraction demonstrates the SOFs maintain their structural stabilities upon light irradiation. More interestingly, the radical‐containing SOFs exhibit efficient photothermal effect under 660 nm light irradiation, which can be applied as photothermal agent for antibacterial application both in vitro and in vivo. This work highlights the construction of RCFs through supramolecular self‐assembly, which may arouse applications in energy, catalysis, photoluminescence, and biomedical fields.
Radical‐containing supramolecular organic frameworks (SOFs) can be easily synthesized by the chaotropic effect of closo‐dodecaborate cluster and 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine. The SOFs exhibit photochromic behavior under 435 nm light irradiation, while showing photothermal effect under 660 nm light irradiation. The radical‐containing SOFs can be applied as effective photothermal antibacterial agent in vitro and in vivo.
Gluten-free noodles, e.g. potato starch noodles, are getting popular due to the increasing population with gluten sensitivity and celiac disease. However, due to the lack of gluten network, the solid ...loss of potato starch noodles during cooking leads to lower textural and sensory attributes. The starch modification provides the opportunity to address these shortcomings. Here, we report the application of heat-moisture treated (HMT) potato starch with added salt as a binder to improve the cooking and textural properties of potato starch noodles. In the presence of sodium tripolyphosphate (STPP) and sodium chloride (SC), starch granules exhibited irregular shapes and deformed crystalline growth rings, agglomerated due to partial gelatinization, and lost double-helical structures and the perfection of crystallites after being subjected to HMT. As affected by the starch-ions interactions and changed water structure, HMT-modified starch with added SC and STPP had higher pasting temperatures, less amylose leaching, and lower gelatinization enthalpies and pasting viscosities than HMT starch without salts. Meanwhile, higher cross-over temperatures and lower G’ values were found in HMT starch with added STPP and SC compared to HMT starch. Iodine-staining micrographs also confirmed the delay in the disintegrating process of starch granules in HMT-modified starch with added SC and STPP. Furthermore, when HMT-modified starch with added SC was applied as binder paste, starch dough owned higher hardness and starch noodles exhibited less solid loss and broken noodles, firmer texture, and better elasticity. The results thus provide the opportunity to improve the textural attributes of potato starch noodles with the application of HMT potato starch and salt as the binder.
Display omitted
•Structural changes of starch before and after HMT as affected by salts are studied.•Adding sodium chloride induces the losses of ordered structure of starch during HMT.•Adding salts delays the disintegrating of starch granules during gelatinization.•HMT starch with added sodium chloride (HPS-SC) has better heat and shear stability.•HPS-SC as a binder improves cooking performance and texture of starch noodles.
Display omitted
•Micro- and molecular structure of dried and wet starch noodles are studied.•Storage stability and shelf-life prediction of wet starch noodles are evaluated.•Cooked wet noodles ...exhibit more evenly network and better cooking properties.•Wet starch noodles have more complete crystallites and ordered structure.•The established model was suitable for predicting shelf life of wet starch noodles.
Cooking performance, micro- and molecular structure, storage stability and shelf-life prediction of high-moisture wet starch noodles (SN) were investigated. SEM images revealed that compared to dried SN, cooked wet SN had more evenly honeycomb-like network with smaller size of pores, indicating stronger interaction among molecules and causing favorable cooking performance. XRD and ATR-FTIR results evidenced that wet SN contained more complete crystallites and higher proportion of crystalline region. During storage, the quality decay of wet SN was mainly associated to the increment of total aerobic viable count (TAVC), titrable acidity and amylase, as well as the decreased textural hardness, overall acceptability and lightness. Based on TAVC, titrable acidity and overall acceptability, predicted shelf-life of vacuum-packed wet SN at 25 °C was 15.31, 21.54 and 16.65 weeks respectively, with relative error all within 20%, proving that the validated model could be an effective tool for monitoring the shelf-life of wet SN.
PDF
