Search

Organic-rich shales from the Triassic Yanchang Formation in the Ordos Basin in China are mainly derived from aquatic organisms with type II kerogen. A reverse maturity trend, derived from the commonly used biomarker maturity parameter Ts/(Ts + Tm) occurs in the depth profiles of the Chang 73 submember and the Chang 8 member. In contrast, maturity proxies derived from aromatic compounds show a normal sequence for more deeply buried Chang 8 samples exhibiting higher maturity levels, as expected. To explain the abnormal phenomenon, multiple controlling factors—including the paleoredox condition, water salinity, the clay mineral content and composition, biodegradation, the primary migration fractionation effect, and organofacies—are considered. It was found that organofacies BC (HIo = 400-250) appear in the Chang 8 samples, while organofacies B (HIo = 400-650) appear in the Chang 73 submember. The results suggest that variation in organofacies has a significant impact on Ts/(Ts + Tm) values, even for samples with the same kerogen type and similar source input, and is primarily responsible for the reverse maturity trend in the depth profiles.

Abstract Introductin Improper gait patterns, impaired balance and foot drop consistently plague stroke survivors, preventing them from walking independently and safely. Neuromuscular electrical stimulation (NMES) technology can help patients reactivate their muscles and regain motor coordination. This study aims to systematically review and summarize the evidence for the potential benefits of NMES on the improvement of gait patterns after stroke. Evidence acquisition PubMed, Cochrane Library, Embase, Science Direct and Web of Science were systematically searched until April 2024, to identify randomized controlled trials with the following criteria: stroke survivors as participants; NMES as intervention; conventional rehabilitation as a comparator; and gait assessment, through scales or quantitative parameters, as outcome measures. Evidence synthesis 29 publications involving 1711 patients met the inclusion criteria. Meta-analysis showed no significant differences in Ten-meter walk test, Fugl-Meyer assessment lower extremity, Modified Ashworth Assessment and asymmetry between the NMES group and the control group. Besides, NMES was associated with changes in outcome indicators such as quantitative gait analysis speed [SMD = 0.53, 95% CI (0.20, 0.85), P = 0.001], cadence [SMD = 0.76, 95% CI (0.32, 1.20), P = 0.0008], affected side step length [SMD = 0.73, 95% CI (0.16, 1.31), P = 0.01], angle of ankle dorsiflexion [WMD = 1.57, 95% CI (0.80, 2.33), P

Abstract Background Metabolic dysfunction-associated steatotic liver disease (MASLD) is a common chronic liver disease. Objective This study aimed to investigate the self-management ability of patients with MASLD, analyse related factors that may affect self-management ability and evaluate the impact of this ability on readmission. Methods The study recruited patients with MASLD admitted to the Department of Infectious Diseases, First Affiliated Hospital of Wenzhou Medical University, between February and October 2021 using the random sampling method. The MASLD diagnosis was based on the guidelines for the prevention and treatment of MASLD. An analysis of patients’ self-management ability was conducted using the self-management ability scale for patients with MASLD. Multiple linear regression analysis was used to analyse the factors influencing this self-management ability, and the readmission rate within 1 year was tracked. The patients were rediagnosed as having MASLD upon readmission to the hospital. Results A total of 241 baseline data items and self-management scale scores for patients with MASLD were collected and investigated. In our study, the normal score range for the self-management scale was 31–155 points, and the self-management scale scores for patients with MASLD was 91.24 ± 16.98, with a low level of self-management accounting for 52.7% and a medium level accounting for 44.8%. The results of the multiple linear regression analysis revealed that marital status, smoking history, fatty liver severity and education were the main factors affecting self-management ability (P

Abstract Mitochondria play a crucial role in the progression of nasopharyngeal carcinoma (NPC). YME1L, a member of the AAA ATPase family, is a key regulator of mitochondrial function and has been implicated in various cellular processes and diseases. This study investigates the expression and functional significance of YME1L in NPC. YME1L exhibits significant upregulation in NPC tissues from patients and across various primary human NPC cells, while its expression remains relatively low in adjacent normal tissues and primary nasal epithelial cells. Employing genetic silencing through the shRNA strategy or knockout (KO) via the CRISPR-sgRNA method, we demonstrated that YME1L depletion disrupted mitochondrial function, leading to mitochondrial depolarization, reactive oxygen species (ROS) generation, lipid peroxidation, and ATP reduction within primary NPC cells. Additionally, YME1L silencing or KO substantially impeded cell viability, proliferation, cell cycle progression, and migratory capabilities, concomitant with an augmentation of Caspase-apoptosis activation in primary NPC cells. Conversely, ectopic YME1L expression conferred pro-tumorigenic attributes, enhancing ATP production and bolstering NPC cell proliferation and migration. Moreover, our findings illuminate the pivotal role of YME1L in Akt-mTOR activation within NPC cells, with Akt-S6K phosphorylation exhibiting a significant decline upon YME1L depletion but enhancement upon YME1L overexpression. In YME1L-silenced primary NPC cells, the introduction of a constitutively-active Akt1 mutant (caAkt1, at S473D) restored Akt-S6K phosphorylation, effectively ameliorating the inhibitory effects imposed by YME1L shRNA. In vivo studies revealed that intratumoral administration of YME1L-shRNA-expressing adeno-associated virus (AAV) curtailed subcutaneous NPC xenograft growth in nude mice. Furthermore, YME1L downregulation, concurrent with mitochondrial dysfunction and ATP reduction, oxidative injury, Akt-mTOR inactivation, and apoptosis induction were evident within YME1L-silenced NPC xenograft tissues. Collectively, these findings shed light on the notable pro-tumorigenic role by overexpressed YME1L in NPC, with a plausible mechanism involving the promotion of Akt-mTOR activation.

ObjectiveThis study aimed to analyse the relevant factors that may affect post-stroke fatigue (PSF) in patients with stroke and further explore the correlation between family functioning and PSF.MethodsPatients who had experienced a first episode of stroke and were admitted to the Department of Neurology of the First Affiliated Hospital of Wenzhou Medical University were rigorously screened. The general data and family functioning of the patients on admission were collected, and their family adaptation, partnership, growth, affection and resolve scores and their PSF on the 5th day of admission were collected using the fatigue severity scale (FSS). Multiple linear regression analysis was then utilized to explore the factors affecting PSF in patients with stroke.ResultsA total of 220 questionnaires were distributed, and 220 were returned, with 212 valid questionnaires and a valid return rate of 96.4%. These 212 patients had a family functioning score of 6.58 ± 2.00 and an FSS score of 36.62 ± 10.96. Spearman’s correlation analysis showed negative correlations between the FSS scores and the adaptation, partnership, growth, affection, resolve and family functioning scores (r = −0.380, −0.505, −0.470, −0.303, −0.281 and −0.712, respectively; p < 0.001). Furthermore, multiple linear regression analysis showed that family functioning (β′ = −0.516), marital status (β′ = −0.244), household income (β′ = −0.185), literacy (β′ = −0.181) and activities of daily living (β′ = −0.084) were influential factors for PSF in patients with stroke (p < 0.05).ConclusionThere is a significant negative correlation between family functioning and PSF, suggesting that better family functioning may help mitigate the severity of post-stroke fatigue. Healthcare providers should identify interventions to help patients and families address fatigue, boost disease recovery, promote patients’ physical and mental health and improve their quality of life.

A pyrolysis hydrocarbon generation experiment was conducted on low-maturity marine shale from the Second White Specks (2WS) Formation of the Cretaceous Colorado Group in the Western Canada Basin. Using GC-MS, quantitative analysis of aromatics in naturally evolved and thermally simulated samples was performed to systematically compare the geochemical characteristics of aromatics in both sets of samples. The results indicated that: (1) In the naturally evolved series of 2WS shale, the absolute contents of trimethylnaphthalene (TMN), tetramethylnaphthalene (TeMN), phenanthrene (P) and methylphenanthrene (MP) were relatively higher andincreased with the degree of evolution. In the thermally simulated series, the absolute contents and trends of P and MP remained consistent with those of naturally evolved series at higher thermal evolution levels, whereas the absolute contents of TMN and TeMN were relatively lower and showed different trends, increasing initially and then decreasing with maturity. (2) The trimethylnaphthalene ratio (TMNR) values of the naturally evolved series increased gradually with burial depth, while the TMNR values of the thermally simulated series decreased initially and then increased. The tetramethylnaphthalene ratio (TeMNR) and methylphenanthrene index (MPI) values of both series showed a consistent pattern: TeMNR values decreased initially and then increased with maturity, while MPI values increased with maturity, suggesting that phenanthrene series compounds effectively indicated shale maturity under both thermal simulation and natural evolution conditions. (3) The thermal simulation experiment was capable of effectively replicating the thermal evolution process of aromatics within a certain temperature range. Specifically, TMNR values of the simulated shale deviated from the naturally evolved shale before 350 ℃ but became consistent after 350 ℃. Similarly, alkyl phenanthrenes-related parameters aligned with those of the naturally evolved shale before 425 ℃ but diverged significantly beyond 425 ℃. This divergence was primarily influenced by the change in aromatic evolution mechanisms when the temperature reached a critical value, as well as by factors such as heating rate and the state of organic matter.

Abstract Background There is a significant increase in the number of SARS-CoV-2 reinfection reports in various countries. However, the trend of reinfection rate over time is not clear. Methods We searched PubMed, Web of Science, Medline, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang for cohort studies, case-control studies, and cross-sectional studies up to March 16, 2023, to conduct a meta-analysis of global SARS-CoV-2 reinfection rate. Subgroup analyses were performed for age, country, study type, and study population, and time-varying reinfection rates of SARS-CoV-2 were estimated using meta-regression. The risk of bias was assessed using the Newcastle-Ottawa Scale and the Joanna Briggs Institute critical appraisal tool. Result A total of 55 studies involving 111,846 cases of SARS-CoV-2 reinfection were included. The pooled SARS-CoV-2 reinfection rate was 0.94% (95% CI: 0.65 -1.35%). In the subgroup analyses, there were statistically significant differences in the pooled reinfection rates by reinfection variant, and study type (P

A good theory of mathematical beauty is more practical than any current observation, as new predictions about physical reality can be self-consistently verified. This belief applies to the current status of understanding deep neural networks including large language models and even the biological intelligence. Toy models provide a metaphor of physical reality, allowing mathematically formulating the reality (i.e., the so-called theory), which can be updated as more conjectures are justified or refuted. One does not need to present all details in a model, but rather, more abstract models are constructed, as complex systems such as the brains or deep networks have many sloppy dimensions but much less stiff dimensions that strongly impact macroscopic observables. This type of bottom-up mechanistic modeling is still promising in the modern era of understanding the natural or artificial intelligence. Here, we shed light on eight challenges in developing theory of intelligence following this theoretical paradigm. Theses challenges are representation learning, generalization, adversarial robustness, continual learning, causal learning, internal model of the brain, next-token prediction, and the mechanics of subjective experience.

Abstract With the rapid development of the Internet of Medical Things (IoMT) and the increasing concern for personal health, sharing Electronic Medical Record (EMR) data is widely recognized as a crucial method for enhancing the quality of care and reducing healthcare expenses. EMRs are often shared to ensure accurate diagnosis, predict prognosis, and provide health advice. However, the process of sharing EMRs always raises significant concerns about potential security issues and breaches of privacy. Previous research has demonstrated that centralized cloud-based EMR systems are at high risk, e.g., single points of failure, denial of service (DoS) attacks, and insider attacks. With this motivation, we propose an EMR sharing scheme based on a consortium blockchain that is designed to prioritize both security and privacy. The interplanetary file system (IPFS) is used to store the encrypted EMR while the returned hash addresses are recorded on the blockchain. Then, the user can authorize other users to decrypt the EMR ciphertext via the proxy re-encryption algorithm, ensuring that only authorized personnel may access the files. Moreover, the scheme attains personalized access control and guarantees privacy protection by employing attribute-based access control. The safety analysis shows that the designed scheme meets the expected design goals. Security analysis and performance evaluation show that the scheme outperforms the comparison schemes in terms of computation and communication costs.

Abstract Background This study aimed to investigate the knowledge, attitudes and practices (KAP) of patients with chronic pharyngitis in Suzhou, China toward laryngopharyngeal reflux (LPR). Methods This cross-sectional study was conducted in patients with chronic pharyngitis in Suzhou, China at the otolaryngology outpatient clinic of the First Affiliated Hospital of Soochow University between November, 2022, and May, 2023. Data was collected through a self-designed online questionnaire encompassing the sociodemographic characteristics and three dimensions of KAP. The questionnaire was administered using SoJump, and data were exported from this platform. Subsequently, statistical analysis, including Structural Equation Modeling, was performed using SPSS 22 software to evaluate the KAP scores. Results A total of 487 valid questionnaires were collected, with 275 (56.35%) female patients. The mean score of KAP were 4.76 ± 2.93 (possible range: 0–11), 33.10 ± 4.46 (possible range: 8–40), 31.29 ± 6.04 (possible range: 8–40), respectively. Pearson’s correlation analysis showed significant positive correlations between knowledge and attitude dimensions (r = 0.413, P

As one of the important means to coordinate the relationship between the development and utilization activities of the coastal zone and the protection of the ecological environment, and to measure the sustainable development capacity of the coastal zone, the quantitative research of the comprehensive evaluation of marine eco-environment carrying capacity (MECC) of the is very important. This study reviews the existing problems in the current integrated assessment of MECC, compares and analyzes the commonly used methods for carrying capacity assessment, and selects a set of potential methods that is suitable for the integrated assessment of MECC in coastal areas according to the characteristics of coastal areas. On this basis, through the analysis of the results of the case application, the practicability and limitations of this set of methods is further discussed, and several improvement suggestions are proposed. The results show that: (1) in view of the complexity and uncertainty of the coastal ecosystem, some traditional and commonly used assessment methods of carrying capacity cannot be well applied to the integrated assessment of MECC in coastal areas; (2) by fully considering the interaction between human activities and the marine eco-environment, this set of potential methods proposed in this study can better support the establishment of the assessment index system, objectively give weight to each assessment index, and quantitatively analyze and evaluate the comprehensive MECC. And thus, it can provide a feasible approach for the integrated assessment of MECC as well as empirical references for ensuring a sustainable coastal development; (3) additionally, it still has several limitations, such as, mainly, the lack of authoritative and unified indicator systems, as well as specific rating standards. Therefore, future studies should focus on related methods for the establishment of assessment indicator system and the classification criteria for evaluation results, so as to improve the assessment system for MECC and thus apply it to a more scientific analysis of the MECC in coastal areas.

The deployment of network security has become a crucial strategy for the development of modern nations, with skilled professionals serving as the core driving force behind cybersecurity efforts.Cultivating cybersecurity talents and fostering team building are essential for China's talent reserves and strategic capital accumulation.With economic globalization, 0-day vulnerabilities have constantly emerged in information systems, attack chains have become increasingly complex, threat targets were difficult to detect, and hidden viruses varied over time.Talents trained by traditional universities for network security were unable to adapt to innovative production and practical activities in the new fields, as it was confined to their training structure system.In order to break through the shackles of the internal administrative structure and traditional curriculum system of universities, and ease the contradiction between the uncertainty of cyberspace security situation and the standardization of talent cultivation, the talent cultivation models based on Bourdieu's theory were studied, the fusion meaning of cultural capital in the academic field was analyzed and three practical standards were put forward in terms of teaching content, cultivation model and teaching opportunity of cyberspace security talents in combination with the actual cases of the “Fang class”.In terms of education content, standards and open knowledge systems were established to meet the differentiated needs of students.The mentorship approach was employed to construct habitus, fostering students’ ability to adapt flexibly to problems by adopting different cognitive thinking modes.Favorable teaching opportunities were utilized by tutors in various roles to promote efficient integration of individuals and fields, helping students establish a valuable and stable mindset.By leveraging Bourdieu's theory to explore the integration path of academic fields, it has leveraged the advantages of independently cultivating high-quality talents, vigorously promoting technological innovation and the healthy ecological development of the industry.

Inflammatory myofibroblastic tumors (IMTs) are rare lesions with distinct clinical, pathological, and molecular characteristics. IMTs typically arise in the abdominal soft tissues, including the mesentery, omentum, and retroperitoneum, followed by the lungs and mediastinum, and usually affect both children and young adults. Herein, we present a rare case of an IMT in the submandibular gland of a 47-year-old male patient. Microscopically, the tumor displayed an infiltrative growth pattern with diffuse glandular tissue destruction. Their backgrounds revealed characteristic spindles and inflammatory cells. Immunohistochemistry revealed positivity for anaplastic lymphoma kinase (ALK), smooth muscle actin, and calponin in neoplastic cells. The inflammatory cells and some neoplastic cells were positive for CD68. In contrast, negative staining for cytokeratin, desmin, and CD30 was observed. Furthermore, fluorescence in situ hybridization revealed ALK gene rearrangements, and next-generation sequencing detected a moesin (MSN)-ALK gene fusion. This case highlights a rare and unique occurrence of IMT originating from the submandibular gland, which exhibited an MSN-ALK gene fusion.

This paper summarized the historical changes of mangrove in China, and the spatial distribution,species composition, changes of mangrove and the main influencing factors in each area. The main factors affecting mangrove ecosystem health in China mainly included: pollution, over culturing, ocean engineering, overfishing and biological invasion. Some suggestions on mangrove protection were proposed, including accelerating mangrove protection legislation, comprehensive improvement of surrounding environment, improving the system of ecological compensation, strengthening publicity and education, promoting the transformation of livelihood, and improving the effect of mangrove restoration in many ways.

In order to improve offshore eco-environment, guarantee national food security, as well as promote the implementation of "blue carbon plan" and the sustainable development of marine fishery economy, this paper overviewed the domestic and international status quo of the development of deep-sea aquaculture, analyzed its current problems in China, identified the potential crucial missions, and proposed the future policy suggestions by integrating some local previous practices. The results showed that there were three predominant problems of China′s deep-sea aquaculture, including the incomplete technique system of equipment and standard, the low level of aquaculture scientific technology, and the weakness in top-level design and policy support. In light of these issues, there were in need of further pushing forward the Chinese deep-sea aquaculture from four priority aspects, including the comprehensive development of planning and environmental assessment in aquaculture areas, the establishment of aquaculture technical system with high-quality and efficient, the construction of diversified and perfect equipment system, and the creation of completed industrial chain; meanwhile, it was recommended to enhance top-level design and industrial layout, establish the sound and diversified investment system, strengthen the role of scientific and technical support, coordinate the relationship between development and eco-environmental protection, and improve the guarantee system for safety production, thereby ensuring the future sustainable development of deep-sea aquaculture in China.

The pressure-state-response (PSR) model was used to establish the evaluation index system of mangrove reserve protection effectiveness in this paper, taking Shankou Mangrove Reserve in Guangxi as an example. Based on the assessment result, some suggestions to improve the protection effectiveness of mangrove reserve were put forward. The results showed that the protection effect of Shankou Mangrove Reserve from 2008 to 2018 was good, and the ecosystem health status was good. At present, the main problems were as follows: there were still some aquaculture ponds in the reserve, which discharged aquaculture wastewater and domestic sewage of residents, resulting in serious eutrophication of seawater. In addition, the construction of professional personnel and community co-management needs to be improved in Shankou Mangrove Reserve.

Large-scale deep neural networks consume expensive training costs, but the training results in less-interpretable weight matrices constructing the networks. Here, we propose a mode decomposition learning that can interpret the weight matrices as a hierarchy of latent modes. These modes are akin to patterns in physics studies of memory networks, but the least number of modes increases only logarithmically with the network width and even becomes a constant when the width grows further. The mode decomposition learning not only saves a significant large amount of training costs but also explains the network performance with the leading modes, displaying a striking piecewise power-law behavior. The modes specify a progressively compact latent space across the network hierarchy, making a more disentangled subspace compared to standard training. Our mode decomposition learning is also studied in an analytic online learning setting, which reveals multiple stages of learning dynamics with a continuous specialization of hidden nodes. Therefore the proposed mode decomposition learning points to a cheap and interpretable route towards the magical deep learning.

Shale gas production is obviously higher within the Silurian Longmaxi Formation than that of the Cambrian Niutitang Formation according to the drilling test results in the northwest Hunan area. To clarify the reasons behind this variation, core samples from the two sets of shales were studied for a comprehensive comparison and analysis of their organic matter (OM) pore structure. Methods were used, including the total organic carbon content test, the vitrinite reflectance test, X-ray diffraction, and focused ion-beam scanning electron microscopy (FIB-SEM). The results show that these two shales have similar reservoir characteristics, both with abundant organic matter and high content of brittle minerals. However, the Longmaxi shale with 2.3% to 3.0%Ro presents lower thermal maturity than the Niutitang shale with over 3.0%Ro. In the case of pore structure associated with OM, a huge difference exists between the two shales. The OM pore shape of the Longmaxi shale is very regular, being mostly round and oval, while the OM pore shape of the Niutitang shale is irregular, being flat with a thin middle and thick and elongated ends. An important factor affecting OM pore evolution is thermal maturity. In turn, the thermal maturity is controlled by the tectonic evolution process, especially the maximum paleo-burial depth. In conclusion, the paleo-burial depth of the Lower Cambrian Niutitang shale in northwest Hunan is too large, which leads to the excessive evolution of organic matter in the shale, and the physical and chemical properties are similar to graphite, which leads to the disappearance of OM pores. Shale gas has no effective reservoir space and is largely dispersed in geological history. At the same time, due to the insufficient hydrocarbon-generation evolution time of the Lower Silurian Longmaxi Formation shale in this area, the shale could not form enough gaseous hydrocarbons and a large amount of effective reservoir space (OM pores with regular shape and large pore size), and finally failed to become a gas reservoir. Therefore, the exploration and development potential of the marine shale gas of the Lower Cambrian Niutitang Formation and the Lower Silurian Longmaxi Formation in northwest Hunan is poor.

Aiming at the security problem of edge server, a trust evaluation algorithm was proposed, which integrated server cooperation reputation and device user feedback to improve the security of edge computing context.In the process of interaction, a fusion algorithm based on objective information entropy theory was used to aggregate the cooperation reputation between servers, and a partial homomorphic encryption algorithm was used to prevent the leakage of user data in the process of interaction.After the interaction, the highly trusted device node was selected to calculate the feedback trust, which overcame the malicious feedback of the traditional mechanism.When calculating the global trust, the expected score of the server and the adaptive weight calculation method were considered, which overcame the limitations of the traditional trust scheme.The experimental results show that the proposed trust calculation scheme has low time complexity and spatial complexity, and can effectively resist the attack of malicious nodes.

Chinese marine source rocks are generally at the stage of high- to over-mature, there are still some uncertainties about whether the existing hydrocarbon isotopic indexes can be directly employed to distinguish the genetic types of marine carbonate natural gas and consequently, gas-oil source correlation can be carried out. In this paper, a series of pyrolysis experiments for hydrocarbon generation with different conditions were carried out using the low-maturity marine carbonate source rocks of Luquan Ⅱ1 type in Yunnan province to analyze the carbon isotope of the collected gas products. The results showed that: ①During the entire thermal evolution stage, the carbon isotope values of kerogen did not vary significantly with the increasing of maturity, while the carbon isotope values of methane and ethane both decreased and then increased with the increase of maturity, showing similar evolution characteristics. In the main oil and gas generation stage, it is significantly smaller than the isotope value of its parent material kerogen. In the over-mature stage (VRo ≥2.2%), the tendency of carbon isotope of ethane to become heavier is obviously accelerated, even greater than the carbon isotope value of its parent material kerogen, showing the characteristics of "coal-type gas". This suggested that we need to be cautious when simply using the carbon isotope values of methane and ethane to identify the type of natural gas. ②At the same maturity, the carbon isotope values obtained from the pyrolysis experiment of semi-closed and semi-open system are lighter than those obtained from the pyrolysis experiment of closed system. This indicates that conventional natural gas reservoirs formed by the discharge of hydrocarbon gas from the same source rock have a certain difference between the carbon isotope values of hydrocarbon gas and the carbon isotope values of shale gas retained in the source, showing the characteristics of "different sources". Attention should also be exercised to the use of carbon isotope templates or regression formulas to carry out gas-source comparisons. ③With the two pyrolysis methods, the carbon isotope value of methane is always lighter than that of ethane in the full evolution stage of the same source rock. This indicated that conventional natural gas reservoirs formed by direct gas supply from single set of source rock do not have "inversion" phenomenon of methane and ethane carbon isotopes.

Abstract This paper examines a scheduling problem with heterogeneous logistics unmanned aerial vehicles (UAVs) in urban environment. Different from traditional vehicle routing problem (VRP), it introduces some new characteristics such as the loading capacity, the maximum flight time and the flight speed. As a variant of VRP, the considered scheduling problem is known to be an non‐deterministic Polynomial (NP)‐hard problem. The UAV scheduling problem model with the heterogeneous UAV settings is formulated first. Secondly, a genetic‐based algorithm framework is presented for solving the scheduling problem, in which the encoding/decoding method, the initial population generation method and genetic operations are delicately designed. In order to reduce the search space and faster the execution of this algorithm, a weight‐based loading method is adopted. For the purpose of performance evaluation and statistical analysis, the proposed algorithm is compared with the other two existing algorithms. The experimental results show that the presented algorithm can solve this problem efficiently.

The release of pollutants in sediment often causes secondary pollution of seawater. In this paper, marine aquaculture sediment was added to seawater in a coastal land–based mesocosm, and the changes in microbial and physicochemical parameters were measured to study the influence of sediment disturbance on seawater. The results showed that sediment disturbance had adverse effects on seawater. After adding and stirring the aquaculture sediment, the concentration of dissolved oxygen (DO) gradually decreased, and those of nutrients gradually increased; in particular, the concentrations of ammonia and dissolved inorganic phosphorus (DIP) increased most sharply. After day 9, a bloom dominated by Chaetoceros occurred. Concentrations of chlorophyll a (Chl-a) increased, and two obvious Chl-a peaks were observed; the trends of DO and pH were similar to that of Chl-a during the bloom period; and DIP and ammonia were exhausted during periods of Chl-a peaks. During the extinction of algal blooms, the concentrations of Chl-a and DO decreased, whereas those of DIP and ammonia increased. The variation trends of bacteria and viruses were similar to that of Chl-a, with two obvious peaks, which were later than those of Chl-a. There were close connections between Chl-a and nutrients, bacteria and viruses and they showed a trend of changes in turn from nutrients to phytoplankton to bacteria to viruses during the experiment. We concluded that bloom formation was mainly affected by nutrients and weather, and the main reason for bloom decline was the depletion of nutrients. The increase in zooplankton, bacteria, and virus abundance was the ecological effect after the occurrence of algal blooms, and they affected the development of algal blooms.

ObjectiveThis study aimed to compare the diagnostic capacity between IVIM and DKI in differentiating malignant from benign thyroid nodules.Material and MethodsThis study is based on magnetic resonance imaging data of the thyroid with histopathology as the reference standard. Spearman analysis was used to assess the relationship of IVIM-derived parameters D, f, D* and the DKI-derived parameters Dapp and Kapp. The parameters of IVIM and DKI were compared between the malignant and benign groups. Binary logistic regression analysis was performed to establish the diagnostic model, and receiver operating characteristic (ROC) curve analysis was subsequently performed. The DeLong test was used to compare the diagnostic effectiveness of different prediction models. Spearman analysis was used to assess the relationship of Ki-67 expression and parameters of IVIM and DKI.ResultsAmong the 93 nodules, 46 nodules were malignant, and 47 nodules were benign. The Dapp of DKI-derived parameter was related to the D (P < 0.001, r = 0.863) of IVIM-derived parameter. The Kapp of DKI-derived parameter was related to the D (P < 0.001, r = -0.831) of IVIM-derived parameters. The malignant group had a significantly lower D value (P < 0.001) and f value (P = 0.013) than the benign group. The malignant group had significantly higher Kapp and lower Dapp values (all P < 0.001). The D+f had an area under the curve (AUC) of 0.951. The Dapp+Kapp had an AUC of 0.943. The D+f+Dapp+Kapp had an AUC of 0.954. The DeLong test showed no statistical significance among there prediction models. The D (P = 0.007) of IVIM-derived parameters and Dapp (P = 0.045) of DKI-derived parameter were correlated to the Ki-67 expression.ConclusionsIVIM and DKI were alternative for each other in in differentiating malignant from benign thyroid nodules.

Although China possesses a large number of islands, knowledge of their overall ecological condition is limited on a national scale. Accordingly, this study developed a comprehensive and quantitative island ecosystem assessment framework that incorporates environmental quality, biological structure, and landscape patterns. The framework was applied to 42 typical, representative islands within China’s coastal regions, including different climatic zones, area sizes, populations, and substratum lithologies. Results showed that the value range of the comprehensive index of island ecosystem condition (CIisland) was significant (from 52.33 to 89.53, 71.72 average), and 85.4% of islands scored either “high” or “good,” indicative of their exceptional condition. However, conditions varied among different island components, indicating different challenges. Environmental quality index (Ienv) values ranged from 60.70 to 94.80 (79.72 average), where primary threats were seawater nutrient pollution, petroleum, and marine organism metal contamination. Biological structure index (Ibio) values ranged from 43.50 to 89.40 (66.10 average), where primary threats were vegetation destruction and a reduction in marine biodiversity within intertidal and subtidal zones. Landscape pattern index (Iland) values varied significantly (from 6 to 100, 72.36 average), where a key characteristic of highly developed islands was low natural landscape (vegetation) coverage. Conditions also varied among island climate zones, lithologies, area sizes, and levels of human habitation. Additionally, island ecosystem conditions were influenced by both natural and anthropogenic factors as well as area size, population, and GDP. Although distance to the mainland significantly correlated to (Ibio), and (CIisland), these parameters did not significantly correlate to (Ienv), which might be explained by that environmental quality was generally conditional on large-scale environments. This assessment is intended to provide a holistic perspective on island conditions in China while identifying key challenges and associated driving factors, which will greatly aid in establishing island-specific sustainable management practices.

Facing the opportunities and challenges in developing the cultivation of cyber security talents in the new security situation, a questionnaire survey on the undergraduate colleges of Jiangsu province, offering network security related majors, is conducted first.Next, multidimensional analysis and comparative study involve eight aspects, such as the distribution scale, the cultivation level, and the curriculum system.Finally, explorations on four aspects, including guarantees of politics, the teaching staff, society, and funds, lead to effective paths on the cultivation of cyber security talents for Jiangsu province under the environment of double tops.

Recent research in the field of oil and gas geochemistry has focused on the catalytic role of minerals in geological history. Thermal simulation experiments are considered a valuable means of studying the formation and transformation of hydrocarbons. In this paper, we review the catalytic mechanisms, processes, and various arguments for different types of minerals in thermal simulation experiments from the perspective of mineral additives. We focus on two categories: (1) minerals that provide direct catalysis, such as clay minerals, alkali metals, carbonate rocks, and some transition metal elements, and (2) minerals, such as serpentine, that promote aqueous hydrogen and act as the material basis, as well as the radioactive element uranium. We also discuss existing disputes and prospects for the development direction of mineral catalytic thermal simulation experiments.

via simple hydrothermal method, CeO2 was in-situ grown onto the CNTs to form CeO2/CNTs nanocomposites were synthesized with cerium nitrate as Ce resource. The morphology and structure were characterized by transmission electron microscopy and X-ray diffraction. The characterizations reveal that CeO2 nanoparticles are uniformly dispersed onto the surface of the pre-acidified CNTs. The electrochemical property of the synthesized nanocomposite was investigated in 0.1 M KCl electrolyte containing 2 mM [Fe(CN)6]3-/4-. The nanocomposites were employed to fabricate electrochemical sensor for phenol detection. The linear range for phenol detection measured by the differential pulse voltammetry method is 1–500 μM. The sensor also exhibits good selectivity, reproducibility and stability. When applied for the river and tap water analysis, it shows good recovery rate.

With the rapid development of cloud computing services, more and more individuals and enterprises prefer to outsource their data or computing to clouds. In order to preserve data privacy, the data should be encrypted before outsourcing and it is a challenge to perform searches over encrypted data. In this paper, we propose a privacy-preserving multi-keyword ranked search scheme over encrypted data in hybrid clouds, which is denoted as MRSE-HC. The keyword dictionary of documents is clustered into balanced partitions by a bisecting $k$ -means clustering based keyword partition algorithm. According to the partitions, the keyword partition based bit vectors are adopted for documents and queries which are utilized as the index of searches. The private cloud filters out the candidate documents by the keyword partition based bit vectors, and then the public cloud uses the trapdoor to determine the result in the candidates. On the basis of the MRSE-HC scheme, an enhancement scheme EMRSE-HC is proposed, which adds complete binary pruning tree to further improve search efficiency. The security analysis and performance evaluation show that MRSE-HC and EMRSE-HC are privacy-preserving multi-keyword ranked search schemes for hybrid clouds and outperforms the existing scheme FMRS in terms of search efficiency.

In recent years, emotional recognition based on Electrophysiological (EEG) signals has become more and more popular. But the researchers ignored the fact that peripheral physiological signals can also reflect changes in mood. We propose an Ensemble Convolutional Neural Network (ECNN) model, which is used to automatically mine the correlation between multi-channel EEG signals and peripheral physiological signals in order to improve the emotion recognition accuracy. First, we design five convolution networks and use global average pooling (GAP) layers instead of fully connected layers; and then the plurality voting strategy is adopted to establish the ensemble model; eventually this model divides emotions into four categories. Based on the simulations on DEAP dataset, the experimental results demonstrate the superiority of the ECNN compared with other methods.

As an emerging cryptographic primitive, Ciphertext-Policy Attribute-Based Encryption (CP-ABE) is suitable for the owner to share his personal health records (PHRs) in mobile healthcare systems (mHealth). Before deploying traditional CP-ABE in real mHealth applications, there are three concerns worth considering. First, the scale of pre-defined attribute universe is lack of scalability. Second, the plaintext access policy sent along with the ciphertext would leak the PHR owner's privacy. Third, it is difficult to identify the malicious user who intentionally disclosed his (partial or modified) private key. In this paper, we present HTAC, a fine-grained policy-hiding and traceable access control scheme for mHealth. In HTAC, the attribute universe is exponentially large and unbounded. Each attribute is expressed by an attribute name and an attribute value. In the encryption phase, the value is hidden in the ciphertext and only the generic attribute name is exposed. The malicious user will be precisely identified by searching the identity linked with the suspicious private key in an identity table. We further extend HTAC by removing the identity table and assigning more explicitly responsibility for the authority and the trace center. Then the storage overhead of tracing the malicious users is constant. The security analysis and performance comparison indicate that HTAC and the extended scheme are secure and practicable for real mHealth.

Intrusion detection as one of the most important approaches to guarantee wireless sensing network security has been studied adequately in previous work. However, with the development of electronic anti-reconnaissance technology, the intruder may obtain the location information of detection nodes and perform path planning to avoid being detected. Such intruder is defined as an “empowered intruder” who will bring new challenges for traditional intrusion detection methods. Moreover, some subareas may have coverage holes due to random initial deployment of detection nodes, the desired effect of detection cannot be achieved. To address these issues, we propose a vehicle collaboration sensing network model, where mobile sensing vehicles and static sensor nodes cooperate to provide intrusion detection against empowered intruders. Our proposal (named as IDEI) consists of a target pursuit algorithm of mobile sensing vehicles and a sleep-scheduling strategy of static nodes. Mobile sensing vehicles will track the empowered intruder and fill up the coverage breaches, while static nodes follow a sleep-scheduling mechanism and will be awakened by detection nodes nearby when the intruder is detected. Simulation experiments are conducted to compare our proposal with existing methods such as KMsn and MTTA in terms of intrusion detection performance, energy consumption and moving distance of sensor nodes. The parameter sensitivity of IDEI is also studied with extensive simulations. The theoretical analysis and simulation results indicate that our proposal can achieve better efficiency and availability.

Ischemic stroke is a major type of stroke worldwide currently without effective treatment, although antiplatelet therapy is an existing option for it. In previous studies, heat shock protein 47 (Hsp47) was found to be expressed on the surface of human and mice platelets and to strengthen the interaction between platelets and collagen. In recent years, Col003 was discovered to inhibit the interaction of Hsp47 with collagen. We evaluated whether the Hsp47 inhibitor Col003 is a promising therapeutic agent for ischemic stroke. Here, we first verified that Hsp47 is also expressed on the surface of rat platelets, and its inhibitor Col003 significantly inhibited thrombus formation in the FeCl3-induced rat carotid arterial thrombus model. Both Col003 and clopidogrel did not alter the bleeding time or coagulation parameters, while aspirin increased the tail-bleeding time (p < 0.05). The low cytotoxicity level of Col003 to rat platelets and human liver cells was similar to those of aspirin and clopidogrel. Col003 inhibited collagen-induced platelet aggregation, adhesion, [Ca2+]i mobilization, P-selectin expression, reactive oxygen species production and the downstream signal pathway of collagen receptors. The results of the middle cerebral artery occlusion model indicated that Col003 has a protective effect against cerebral ischemic–reperfusion injury in rats. The Hsp47 inhibitor Col003 exerted antiplatelet effect and protective effect against brain damage induced by ischemic stroke through the inhibition of glycoprotein VI (GPVI)and mitogen-activated protein kinase (MAPK) signaling events, which might yield a new antiplatelet agent and strategy to treat ischemic stroke.

Cu-Ni oxide nanocomposite was synthesized via solvothermal method with nickel (II) nitrate and copper nitrate as Ni and Cu resource respectively. AuNPs/oxide nanocomposite was obtained by dispersing the oxide into the pre-synthesized Au colloid. Transmission electron microscope (TEM) shows that the synthesized oxides are nanoplate morphology. Interplanar distance from the high resolution TEM (HRTEM) image shows that the Ni and Cu in the oxide are multivalent state. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization further proves that the Ni and Cu are multivalent state, and the Au is Au0 form in the nanocomposte. EDS-mapping images confirm large numbers of AuNPs are uniformly absorbed onto the ultra-thin multivalent Cu-Ni oxide nanoplate. The electrochemical properties of multivalent oxide (m-v oxide) with or without AuNPs decoration are investigated in 0.1 M potassium chloride electrolyte with 2.0 mM Ferri/Ferro-Cyanide. When employed for the electrochemical catalysis in methanol oxidation reaction (MOR), the AuNPs/m-v oxide exhibits better electrochemistry performance than m-v oxide. The current density of AuNPs/m-v oxide (21.1 mA/cm2) is 3.4 times bigger than that of m-v oxide/GCE (6.2 mA/cm2). What’s more, it shows good electrochemical stability and lower slope of the Tafel plot (41.87 mV/dec).

Neural networks with recurrent asymmetric couplings are important to understand how episodic memories are encoded in the brain. Here, we integrate the experimental observation of wide synaptic integration window into our model of sequence retrieval in the continuous time dynamics. The model with non-normal neuron interactions is theoretically studied by deriving a random matrix theory of the Jacobian matrix in neural dynamics. The spectra bears several distinct features, such as breaking rotational symmetry about the origin, and the emergence of nested voids within the spectrum boundary. The spectral density is thus highly nonuniformly distributed in the complex plane. The random matrix theory also predicts a transition to chaos. In particular, the edge of chaos provides computational benefits for the sequential retrieval of memories. Our paper provides a systematic study of time-lagged correlations with arbitrary time delays, and thus can inspire future studies of a broad class of memory models, and even big data analysis of biological time series.

No definitive blood markers of DWI-FLAIR mismatch, a pivotal indicator of salvageable ischemic penumbra brain tissue, are known. We previously reported that CDC42 and RHOA are associated with the ischemic penumbra. Here, we investigated whether plasma CDC42 and RHOA are surrogate markers of DWI-FLAIR mismatch. Sixteen cynomolgus macaques (3 as controls and 13 for the stroke model) were included. Guided by digital subtraction angiography (DSA), a middle cerebral artery occlusion (MCAO) model was established by occluding the middle cerebral artery (MCA) with a balloon. MRI and neurological deficit scoring were performed to evaluate postinfarction changes. Plasma CDC42 and RHOA levels were measured by enzyme-linked immunosorbent assay (ELISA). The stroke model was successfully established in eight monkeys. Based on postinfarction MRI images, experimental animals were divided into a FLAIR (−) group (N = 4) and a FLAIR (+) group (N = 4). Plasma CDC42 in the FLAIR (−) group showed a significant decrease compared with that in the FLAIR (+) group (p < 0.05). No statistically significant difference was observed for plasma RHOA. The FLAIR (−) group showed a milder neurological function deficit and a smaller infarct volume than the FLAIR (+) group (p < 0.05). Therefore, plasma CDC42 might be a new surrogate marker for DWI-FLAIR mismatch.

Cr-MOF nanoparticles were synthesized by a simple hydrothermal method, and their morphology and structure were characterized by SEM, TEM, and XRD techniques. The Cr-MOF modified glassy carbon electrode (Cr-MOF/GCE) was well constructed and served as an efficient electrochemical sensor for the detection of p-nitrophenol (p-NP). It was found that the Cr-MOF nanoparticles had significant electrocatalytic activity toward the reduction of p-NP. The Cr-MOF-based electrochemical sensor exhibited a low detection limit of 0.7 μM for p-NP in a wide range of 2~500 μM and could maintain excellent detection stability in a series of interfering media. The electrochemical sensor was also practically applied to detect p-NP in a local river and confirmed its validity, showing potential application prospects.

With the continuous development of social network application,user’s personal social data is so sensitive that the problem of privacy protection needs to be solved urgently.In order to reduce the network data sensitivity,a differential privacy protection scheme BCPA based on edge betweenness model was proposed.The 2K sequence corresponding to the graph structure based on the dK model was captured,and 2K sequences based on the edge betweenness centrality were reordered.According to the result of reordering,the 2K sequence was grouped into several sub-sequences,and each sub-sequence was respectively added with noise by a dK perturbation algorithm.Finally,a social network graph satisfying differential privacy was generated according to the new 2K sequences after integration.Based on the real datasets,the scheme was compared with the classical schemes through simulation experiments.The results demonstrate that it improves the accuracy and usability of data while ensuring desired privacy protection level.

As an emerging application of smart healthcare, mobile healthcare crowd sensing (MHCS) has become a research hotspot. However, how to ensure the confidentiality and integrity of data and protect the privacy of user is still a challenge for MHCS. To handle these issues, an effective and secure privacy protection scheme is indispensable. Recently, a large-scale concurrent data anonymous batch verification scheme for mobile healthcare crowd sensing was proposed by Liu et al. Unfortunately, we demonstrate that their scheme is insecure. This paper presents an improved anonymous scheme based on certificateless aggregate signature (CL-AS) for MHCS. First, considering the efficiency and the characteristics of the MHCS, the technique of aggregate signature is adopted, which can achieve batch verification and greatly save the bandwidth and computation resources. Second, anonymous communication is carried out in this scheme to realize privacy preservation. Third, based on certificateless cryptography, the proposed scheme can simplify the complicated certificate management and eliminate the key escrow problem. In addition, our scheme is provably secure against the existential forgery on adaptively chosen message attack in the Random Oracle Model assuming the computational Diffie-Hellman problem is intractable. Furthermore, security and efficiency analysis shows that our scheme is secure and efficient.

In order to improve the sensing efficiency of the sensor network, a type of energy-balanced tree-based data collection strategy with mobile Sink (ETDC) is proposed. Based on the minimum cost data gathering tree, several sub-trees with similar scales and small differences in energy consumption are built for data gathering. Moreover, the roots of these sub-trees are regarded as the traversal points, and the moving trajectory of Sink is obtained with the help of these points. In addition, to further reduce energy consumption on communication and the end-to-end delay, roles of some traversal nodes and relay nodes are exchanged. The experimental results show that, compared with the typical mobile Sink based data collection methods such as VGDD and VGDR, ETDC performs well in reducing path length, enhancing the success rate of data transmission, and prolonging the network lifetime.

Traditional searchable encryption schemes adopting the bag-of-words model occupy massive space to store the document set's index, where the dimension of the document vector is equal to the scale of the dictionary. The bag-of-words model also ignores the semantic information between keywords and documents, which could return non-relevant search results to users. The neutral-network based natural language processing method - Doc2Vec model use word's and paragraph's context information to extract documents' features. The features contain latent semantics information and can measure the similarity between documents. In this paper, we adopt the Doc2Vec model to achieve a semantic-aware multikeyword ranked search scheme. Doc2Vec model uses the distributed representation of words and documents with a modest dimensionality of vectors while trained on a dataset with a few hundred of millions of words. Documents' distributed representations are extracted as documents feature vector by Doc2Vec model and utilized as the search index. The features of the queried keywords are also extracted as the query feature vector, and the secure inner product operation is adopted to achieve privacy-preserving semantic search with the query feature vector and index. Our scheme can support dynamic update on the document set with Doc2Vec model. The experiment on a real-world dataset shows that the fixed-length feature vector can improve the time and space efficiency on the semantic-aware search.

Nine samples collected from the Upper Cretaceous Second White Speckled Shale Formation at the Highwood River outcrop in southern Alberta were geochemically characterized for their oil contents, physical states, and chemical compositions. Cold extraction was performed on 8–10 mm and 2–5 mm chips sequentially to obtain the first and second extractable organic matter (EOM-1 and EOM-2), while Soxhlet extraction was performed on powder from previously extracted chips to obtain the third extract (EOM-3). EOM-1 can be roughly regarded as free oil and EOM-2 is weakly adsorbed on mineral surfaces, while EOM-3 may represent the oil strongly adsorbed on kerogen. While both extraction yields and Rock-Eval pyrolysates differed from their original values due to the evaporative loss during outcropping, there was a generally positive correlation between the total EOM and total oil derived from Rock-Eval pyrolysis. EOM-1 was linearly correlated with Rock-Eval S1, while the extractable S2 content was well correlated with the loss of TOC, suggesting that TOC content was the main constraint for adsorbed oils. A bulk composition analysis illustrated that EOM-1 contained more saturated hydrocarbons, while EOM-3 was enriched in resins and asphaltenes. More detailed fractionation between the free and adsorbed oils was demonstrated by molecular compositions of each extract using quantitative GC-MS analysis. Lower-molecular-weight n-alkanes and smaller-ring-number aromatic compounds were preferentially concentrated in EOM-1 as compared to their higher-molecular or greater-ring-number counterparts and vice versa for EOM-3. Fractionation between isoprenoids and adjacent eluted n-alkanes, isomers of steranes, hopanes, alkylnaphthalenes, alkylphenanthrenes and alkyldibenzothiophenes was insignificant, suggesting no allogenic charge from deep strata. Strong chemical fractionation between saturated and aromatic hydrocarbon fractions was observed with EOM-1 apparently enriched in n-alkanes, while EOM-3 retained more aromatic hydrocarbons. However, the difference between free and adsorbed state oils was less dramatic than the variation from shales and siltstones. Lithological heterogeneities controlled both the amount and composition of retained fluids. Oil that resided in shales (source rock) behaved more similar to the EOM-3, with diffusive expulsion leading to the release of discrete molecules from a more adsorbed or occluded phase to a more free phase in siltstones with more connected pores and/or fractures (reservoir). Under current technical conditions, only the free oil can flow and will be the recoverable resource. Therefore, the highest potential can be expected from intervals adjacent to organic-rich beds. The compositional variations due to expulsion and primary migration from source rocks to reservoirs illustrated in the present study will contribute to a better understanding of the distribution of hydrocarbons generated and stored within the shale plays.

To the accurate reconstruction of the hydrocarbon generation history in the Dongying Depression, Bohai Bay Basin, East China, core samples of the Eocene Shahejie Formation from 3 shale oil boreholes were analyzed using organic petrology and organic geochemistry methods. The shales are enriched in organic matter with good to excellent hydrocarbon generation potential. The maturity indicated by measured vitrinite reflectance (%Ro) falls in the range of 0.5–0.9% and increases with burial depth in each well. Changes in biomarker and aromatic hydrocarbon isomer distributions and biomarker concentrations are also unequivocally correlated with the thermal maturity of the source rocks. Maturity/depth relationships for hopanes, steranes, and aromatic hydrocarbons, constructed from core data indicate different well locations, have different thermal regimes. A systematic variability of maturity with geographical position along the depression has been illustrated, which is a dependence on the distance to the Tanlu Fault. Higher thermal gradient at the southern side of the Dongying Depression results in the same maturity level at shallower depth compared to the northern side. The significant regional thermal regime change from south to north in the Dongying Depression may exert an important impact on the timing of hydrocarbon maturation and expulsion at different locations. Different exploration strategies should be employed accordingly.

The binary perceptron is a fundamental model of supervised learning for nonconvex optimization, which is a root of the popular deep learning. The binary perceptron is able to achieve a classification of random high-dimensional data based on the marginal probabilities of binary synapses. The relationship between the belief propagation instability and the equilibrium analysis of the model remains elusive. Here, we establish the relationship by showing that the instability condition around the belief propagation fixed point is identical to the instability for breaking the replica symmetric saddle-point solution of the free-energy function. Therefore our analysis will hopefully provide insight towards other learning systems in bridging the gap between nonconvex learning dynamics and statistical mechanics properties of more complex neural networks.

Crude oil maturity assessment is a vital goal for petroleum geochemistry, and equally important is the exploration of maturity indicators of sufficient credibility. While most molecular proxy parameters have been extensively used and have provided some useful insights; the component ratios approach is somewhat limited in validity regarding oil maturity characterization for variable reasons. Novel thermal trends of hopanes and steranes were observed in a series of hydrous pyrolysates of an immature coal (0.49 %Ro) generated at eight target temperatures ranging from 250–375 °C (measured vitrinite reflectance of 0.71–0.91 %Rm), which–further substantiated this idea. Expelled oil and extractable bitumen were combined as the total soluble organic material (tSOM) for each pyrolysis experiment to mitigate the effects of primary expulsion fractionation. While bitumen extracted from the original coal—the 250 °C tSOM—the 275 °C tSOM (0.49–0.73 %Rm) sequence recorded normal increases in C31 αβ-hopane 22S/(22S + 22R) and decreases in C29–C30 βα-moretane/αβ-hopane ratios, low values and continuous decreases in C29 5α-sterane 20S/(20S + 20R) and ββ/(αα + ββ), Ts/(Ts + Tm) and C29Ts/(C29Ts + C29 αβ-hopane) suggested no biomarker thermal isomerization but predominant control from precursor-to-biomarker transformation. Continuous increases in 22S/(22S + 22R) until 1.43 %Rm accorded with thermal isomerization, but a delayed ratio equilibration at 1.43 %Rm again suggested biomarker precursor interference, which also played a role in the reductions in 20S/(20S + 20R) and ββ/(αα + ββ) to 0.9 %Rm, whereas increasing and high values of C29–C30 βα-moretane/αβ-hopane ratios occurring during 0.73–1.43 %Rm. Reversals in 22S/(22S + 22R) and fluctuations in 20S/(20S + 20R) and ββ/(αα + ββ) at elevated maturity levels with minimum yields of biomarker precursors were predominantly controlled by differential isomer degradative rates. These rarely reported thermal distribution patterns of biomarkers illustrated very complicated biomarker generation–destruction processes during maturation and suggested that the release of bond biomarker to the free status may govern the biomarker maturity ratios rather than thermal isomerization. While the rapid heating conditions and high temperatures in pyrolysis differ inevitably from natural evolution under geological conditions, our study unveiled that unusual biomarker ratios in geological samples could be the norm, contradictory to common beliefs. Accordingly, we propose that isomer concentration is an essential tool to validate maturity estimation of organic matter by isomer ratios, especially for highly mature oils and sediment extracts.

Lower Cambrian shale and lower Silurian shale are both typical of oil-prone kerogen and siliceous composition, but different in thermal maturities. Porosity differences were determined in marine shales between the two shales. Measurements were utilized including organic geochemistry, XRD, scanning electron microscopy (SEM) and N2 gas adsorption. Pore volume (PV) of lower Silurian shale was approximately 1.5 times higher than that of lower Cambrian shale, and pore surface area (PSA) of lower Silurian shale was almost 2.5 times higher than that of lower Cambrian shale. Lower Cambrian shale and lower Silurian shale possess similar materials, but distinctive thermal degrees. Evolution mechanisms of different types of pores, especially organic matter (OM)-hosted pores, may trigger this different pore features. Pores of rigid framework are the residue of primary interparticle pores during the burial history. Pores associated with clay flakes can be preserved well adjacent to rigid grains or secondary minerals acting as rigid frameworks or grain supporters. Dissolved pores in both lower Cambrian shale and lower Silurian shale barely contribute to the total porosity and mean little to the permeability. Both excessive OM content and over thermal maturity are detrimental to development of OM-hosted pores. Rigid particles, clay flakes, and OM commonly co-exist within shale matrix. Rigid grains act as supporters, clay flakes confine ample space, and OM first migrates into and provides secondary OM-hosted pores. In this condition, pores can be preserved owing to associating matrix with good mechanic and chemical stability. The significant differences of structural settings result into various hydrocarbon explosion efficiency and different pressure circumstance, which consequently leads to the different pore features between the two shales. For lower Cambrian shale, overpressure circumstance diminish if hydrocarbon expels outside of the shale system, and OM-hosted pores destroy through compaction. Sustaining overpressure and abundant residue hydrocarbon (migrated OM) make positive contributions to the pore properties, in terms of numbers, diameters and connectivity of the lower Silurian shale samples.

As an emerging technique in 5G cellular networks, D2D communication efficiently utilizes the available resources. However, the concerns of data security, identity privacy, and system scalability have not been sufficiently addressed. In this paper, we propose a robust and scalable data access control scheme (RSDAC) in D2D communication, where the key build block is a multi-authority ciphertext-policy attribute-based encryption (MA-CP-ABE) with the large universe and verifiable outsourced decryption. In RSDAC, the system attribute universe is scalable, which is exponentially large without resource waste. Each base station (BS) governs the whole attribute universe individually. The data owner can define any monotonic access structure to encrypt its data. During the key generation phase, each BS can independently verify the user’s legitimacy and then generate an intermediate key for the legal user according to its attribute set. A core network server (CNS) acts as the central authority which will generate the final private key for the user basing on his intermediate key. We also design an efficient method to offload the complicated decryption to some devices with adequate computation resource and further check the correctness of decryption result. The security analysis and performance comparison indicate that our scheme is secure, efficient, and applicable.