Buried Environment Research Articles

Evaluation of Priority Control District Metered Area for Water Distribution Networks Using Water Quality-Related Big Data

Partitioning methodologies such as district metered areas (DMAs) are being applied to the stable maintenance of water distribution network systems in normal conditions such as daily operation and abnormal conditions such as water quality and leakage accidents. However, management and evaluation through the use of existing DMAs generally only have the primary goal of stable water quantity and pressure management. Therefore, the methodology can be limited to achieving the direct effects of water quality parameters such as decreased water age, proper management of residual chlorine, and decreased water quality complaints. This study uses a methodology for determining and prioritizing water quality-oriented Priority Control District Metered Areas (PCDMAs) for stable water quality management to respond to the recent large-scale rusty (red) water crisis in Korea. First, 4 evaluation criteria and 11 evaluation indicators were derived using various water quality-related structured data (water quality measurement data, pipeline data, etc.) and unstructured data (water quality complaints, etc.) based on the Geographic Information System (GIS). A comprehensive prioritization assessment was carried out with multi-criteria decision-making methods based on the analytic hierarchy process. As a result, particular indicators of complaint of water quality and the existence of vulnerable facilities (hospitals, school, etc.) were analyzed as the top five priorities, and it was shown that to be important criteria in determining water quality-oriented PCMDAs. Finally, the proposed methodology was applied to the B metropolitan city of the Republic of Korea, and the evaluation results of all the districts were derived and analyzed. The study shows that the data-based water distribution network PCDMAs selection methodology can be used as a decision-making tool to improve the accuracy and reliability of the operation and management (O&M) of the water distribution operator’s water distribution network. In future research, it will be necessary to evaluate PDDMA with detailed data related to the pipe deterioration (buried environment, the condition of internal/external of the pipe, etc.), which had a significant threshold due to data limitations. And it would be possible to make a real-time evaluation of PCDMA with the real-time water quality test data.

Malformations in Late Devonian brachiopods from the western Junggar, NW China and their potential causes.

Although malformations are found in both extant organisms and the fossil record, they are more rarely reported in the fossil record than in living organisms, and the environmental factors causing the malformations are much more difficult to identify for the fossil record. Two athyrid brachiopod taxa from the Upper Devonian Hongguleleng Formation in western Junggar (Xinjiang, NW China) show distinctive shell malformation. Of 198 Cleiothyridina and 405 Crinisarina specimens, 18 and 39 individuals were malformed, respectively; an abnormality ratio of nearly 10%. Considering the preservation status and buried environment of the abnormal specimens, and analysis of trace elements and rare earth elements from whole-rock and brachiopod shells, we conclude that the appearance of malformed athyrids is likely related to epi/endoparasites, or less likely the slightly higher content of heavy metal in the sea.

Biogenic Methane Accumulation and Production in the Jurassic Low-Rank Coal, Southwestern Ordos Basin

Geological conditions are the key for coalbed methane (CBM) accumulation and production. However, the geological feature of CBM accumulation and production in the Jurassic of Ordos Basin lacks systematic and detailed evaluation, resulting in poor CBM production in this area. This study has determined the genetic types of gas according to geochemistry characteristics of the gas, the geological factors to control CBM accumulation and production performance were revealed, and a comprehensive method was established to evaluate favorable areas based on 32 sets of CBM well production data from Jurassic Yan’an Formation. The results show the coal macerals are rich in inertinite (41.13~91.12%), and the maximum reflectance of vitrinite (Ro,max) in coal is 0.56~0.65%. According to gas compositions and carbon isotopes analysis, the δ13C(CH4) is less than −55‰, and the content of heavy hydrocarbon is less than 0.05%. The value of C1/(C2 + C3) is 6800~98,000, that is, the CBM is a typical biogenic gas of low-rank coal. The CBM accumulation model is the secondary biogenic on the gentle slope of the basin margin, in which gas content is closely related to buried depth and hydrodynamic environment, i.e., the high gas content areas are mainly located in the groundwater weak runoff zone at the burial depth of 450 m~650 m, especially in the syncline. Meanwhile, gas production mainly depends on the location of the structure. The high gas production areas of vertical wells were distributed on the gentle slope with high gas content between anticline and syncline, and the horizontal wells with good performance were located near the core of the syncline. According to the above analysis combined with the random forest model, the study area was divided into different production favorable areas, which will provide a scientific basis for the CBM production wells.

CFD analysis and calculation models establishment of leakage of natural gas pipeline considering real buried environment

Different from the above ground pipeline, the soil characteristics and ground conditions have a great impact on the risk of leakage accident for buried natural gas pipeline. In this paper, the effects of ground conditions and soil characteristics on methane leakage and diffusion were studied by using numerical simulation. The two processes of methane leakage and diffusion, the methane leakage rate and the methane diffusion Early Warning Boundary (EWB) were investigated. Finally, based on the least square method and multiple regression theory, the calculation models of methane leakage rate and EWB were established. The results showed that: Compared with Unhardened Surface Ground (UHSG) condition, Hardened Surface Ground (HSG) increased the distribution of pressure, velocity and methane concentration in soil. The viscous resistance coefficient and inertial resistance coefficient of soil had a great influence on the methane leakage rate, while the ground conditions did not. Both ground conditions and soil characteristics had a certain impact on the EWB of methane diffusion. The average error of methane leakage rate direct calculation model was 4.48%, and the average error of EWB calculation model under HSG and UHSG condition was 3.59% and 7.77% respectively. The methane leakage rate and the EWB calculation models suggest the soil characteristics as independent variables and can provide the rapid calculation of leakage rate and EWB under any soil characteristics without the help of computer iterative solution. The methane leakage rate direct calculation model makes up for the vacancy of calculation method of leakage rate of buried pipeline under different soil characteristics.

A new inactive conformation of SARS-CoV-2 main protease.

The SARS‐CoV‐2 main protease (Mpro) has a pivotal role in mediating viral genome replication and transcription of the coronavirus, making it a promising target for drugs against the COVID‐19 pandemic. Here, a crystal structure is presented in which Mpro adopts an inactive state that has never been observed before, called new‐inactive. It is shown that the oxyanion loop, which is involved in substrate recognition and enzymatic activity, adopts a new catalytically incompetent conformation and that many of the key interactions of the active conformation of the enzyme around the active site are lost. Solvation/desolvation energetic contributions play an important role in the transition from the inactive to the active state, with Phe140 moving from an exposed to a buried environment and Asn142 moving from a buried environment to an exposed environment. In new‐inactive Mpro a new cavity is present near the S2′ subsite, and the N‐terminal and C‐terminal tails, as well as the dimeric interface, are perturbed, with partial destabilization of the dimeric assembly. This novel conformation is relevant both for comprehension of the mechanism of action of Mpro within the catalytic cycle and for the successful structure‐based drug design of antiviral drugs.

Composition analysis and identification of ancient glass products

Glass products are an important material evidence of the early trade exchanges between China and the West. Under the influence of buried environment, the weathering of glass leads to the change of its chemical composition proportion, which then affects the judgment of cultural relic category. This paper analyzes and identifies the components of ancient glass products by combining sample data.In order to analyze the influencing factors of weathering of cultural relics samples, the paper analyzes the high potassium and lead barium glass types and observes the relationship between the pattern and color of the sample, and the whole chi square independence test is used to obtain the difference rules of glass category, decoration and color classification. For the chemical composition content prediction, the prediction model was built and predicted by the sample mean difference.In this paper, the chemical composition of the unknown category of glass relics was analyzed and identified by training on the valid data in Form 2. For the sensitivity of the classification results, the sensitivity formula was applied to calculate a sensitivity of 0.125.

Corrosion of Longquan celadons in the marine environment: study on the celadons from the Dalian Island shipwreck of the Yuan Dynasty

The Dalian () Island shipwreck of the Yuan Dynasty (1271–1368 CE) was located in the sea area of Pingtan (), Fujian () Province, China. A total of 603 Longquan () celadon wares were excavated, some of which have been severely corroded. In this study, two celadon specimens with severe corrosion were selected to investigate the corrosion mechanism in the marine environment. Optical microscopy (OM), scanning electron microscopy equipped with energy dispersive X-ray spectrometry (SEM–EDS), X-ray diffraction analysis (XRD), Micro-Raman spectroscopy, and thermal expansion analysis were applied to analyze the microstructure of the glaze, corrosion morphology, and composition of corrosion products, and the corrosion mechanism was discussed in depth. The results showed that these two celadon wares are opaque matt glaze, in which the anorthite crystallization-phase separation structure with low chemical stability was found, which was more likely to be corroded. There are three possible stages in the corrosion process of the glaze. The first stage is mainly the long-term cation exchange reaction. Then, because of the corrosion of the CaO-rich droplet phase and the crystal-glass phase interface layer, the porous structure and many microcracks may be formed, promoting the corrosion process. Finally, many corrosion craters, caused by the shedding of anorthite crystals, may appear on the glaze surface. The quintinite group minerals in the glaze were probably formed during the corrosion process, which may be related to the marine buried environment and the corrosion of the glaze. This study discussed the influencing factors of the corrosion process of celadon wares in the marine environment from the perspective of microstructure for the first time, which is of great significance to the study of the corrosion mechanism of ancient ceramics.

Identification of antemortem and postmortem fractures in a complex environment by FTIR spectroscopy based on a rabbit tibial fracture self-control model.

The identification of antemortem and postmortem fractures is a critical and challenging task for forensic researchers. Based on our preliminary studies, we explored whether the combination of Fourier transform infrared spectroscopy (FTIR) and chemometrics can identify antemortem and postmortem fractures in complex environments. The impacts of the four environments on the bone spectrum were analyzed by principal component analysis (PCA). It was found that the bone degradation rate in the submerged and ground surface (GS) environments was higher than that in the buried and constant temperature and moisture (CTM) environments. Additionally, the bone degradation rate in buried environment higher than that in the CTM environment. The average spectrum, PCA and partial least squares discriminant analysis (PLS-DA) results all revealed that there were significant differences between the antemortem fracture and the remaining three groups in a complex environment. Compared with the antemortem fracture, the antemortem fracture control (AFC) and postmortem fracture control (PFC) tended to be more similar to the postmortem fracture. According to the loading plot, amide I and amide II were the main components that contributed to the identification of the antemortem fracture, AFC, postmortem fracture, and PFC. Finally, we established a differential model for the antemortem and postmortem fractures (an accuracy of 96.9%), and a differentiation model for the antemortem fracture, AFC, postmortem fracture, and PFC (an accuracy of 87.5%). In conclusion, FTIR spectroscopy is a reliable tool for the identification of antemortem and postmortem fractures in complex environments.

Formation environments and mechanisms of multistage paleokarst of Ordovician carbonates in Southern North China Basin

With the reduction of oil and gas reserves and the increase of mining difficulty in Northern China, the carbonate rocks in Southern North China Basin are becoming a significant exploration target for carbonate reservoirs. However, the development characteristics, formation stages, formation environments and mechanisms of the carbonate reservoirs in Southern North China Basin are still unclear, which caused the failures of many oil and gas exploration wells. This study focused on addressing this unsolved issue from the Ordovician carbonate paleokarst in the Huai-Fu Basin, which is located in the southeast of Southern North China Basin and one of the key areas for oil and gas exploration. Based on petrology, mineralogy and geochemical data, pore types, distribution characteristics, and formation stages of the Ordovician paleokarst were analyzed. Then, in attempt to define the origins of porosity development, the formation environments and mechanisms were illustrated. The results of this study showed that pore types of the Ordovician carbonates in the Huai-Fu Basin are mainly composed of intragranular pores, intercrystalline (intergranular) pores, dissolution pores (vugs), fractures, channels, and caves, which are usually in fault and fold zones and paleoweathering crust. Furthermore, five stages and five formation environments of the Ordovician paleokarst were identified. Syngenetic karst, eogenetic karst, and paleoweathering crust karst were all developed in a relatively open near-surface environment, and their formations are mainly related to meteoric water dissolution. Mesogenetic karst was developed in a closed buried environment, and its formation is mainly related to the diagenesis of organic matters and thermochemical sulfate reduction in the Permian-Carboniferous strata. Hydrothermal (water) karst was developed in a deep-buried and high-temperature environment, where hydrothermal fluids (waters) migrated upward through structures such as faults and fractures to dissolve carbonate rocks and simultaneously deposited hydrothermal minerals and calcites. Lastly, a paleokarst evolution model, combined with the related porosity evolution processes, nicely revealed the Ordovician carbonate reservoir development. This study provides insights and guidance for further oil and gas exploration in the Southern North China Basin, and also advances our understanding of the genesis of carbonate paleokarst around the world.

Instantaneous frequency analysis of in-plane bending mode of cylindrical shells in buried environment

Instantaneous frequency analysis of in-plane bending mode of cylindrical shells in buried environment

Burial dolomitization, the genesis of dolomite in the Dapu Formation (Upper Carboniferous), Guixinan area, Youjiang basin, Southwest China: petrologic and geochemical evidence

The genesis of dolomite is an intensively debated and extensively studied problem in the field of carbonate sedimentology. This study focuses on the dolomite of the Dapu Formation in the Guixinan area, with the aim of deciphering the mechanism of dolomitization in the Dapu Formation. Three types of sedimentary environment, including the open marine of inner ramp, the restricted marine of inner ramp, and the shoal of inner ramp, have been identified. Three types of dolostone (DI, DII and DIII) identified in the study area with massive structure had close relationship with fault structures, and contacted with limestone in curved diffuse way on the outcrop. Both of the above points indicated diagenetic dolomite. Three types of dolomite (D1, D2 and D3) displayed similar dark—light purple red luminescence, indicating that the characteristics of their diagenetic fluids were similar. The planar-s to nonplanar dolomite crystals indicated that the temperature was more than 50 °C. The mineral assemblage including D2, D3, and silicate minerals (feldspar, tremolite and actinolite) suggested contact metamorphism and tht the diagenetic fluid was rich in silicon and magnesium. The dolomitization process was not influenced by the leaching of meteoric water in surface or shallow buried environment and hydrothermal fluids, based on the corrected REE characteristics. The range of the δ18O of dolostone samples showed that the burial dolomitization had taken place in high-temperature environment. The lower 87Sr/86Sr ratio of the dolostone samples than the coeval seawater meant that the diagenetic fluid was derived from the alteration of mid-ocean ridge basalt. Based on the geologic setting, it was speculated that the burial dolomitization was driven by the hydro-tectonic processes in the passive margin burial diagenesis hydrologic realm. In brief, magnesium came from the low-temperature alteration of ocean basalts, the thermohaline and compactional flow supplied hydrodynamic condition, and the synsedimentary fault zones-supplied channels.

Non-destructive in situ Raman spectroscopic investigation of corrosion products on the bronze dagger-axes from Yujiaba site in Chongqing, China

Corrosion products on 23 bronze dagger-axes unearthed from different tombs dating to the Warring States period at Yujiaba site, Kai County, Chongqing, China, were characterized non-destructively by Raman spectroscopy and optical microscopy (OM). The results showed that Cu corrosion products such as Cu hydroxide sulfate, Cu hydroxide carbonate, Cu hydroxide phosphate, Cu chloride hydroxide, Cu sulfide, Cu oxide, Pb corrosion products such as Pb oxide, Pb carbonate and Pb chlorine phosphate/arsenate (Pb5((As,P)O4)3Cl), and Sn oxide were all detected. Of 23 bronze dagger-axes, 15 were found with mimetite-pyromorphite, whereas 2 with Cu chloride hydroxide may indicate that chlorine ion can combine with Pb more easily than Cu in this special environment. Sulfate ion, phosphoric ion, chloride ion, carbonate ion or bicarbonate ion, and microorganism in the buried environment are the main factors which influenced the formation of corrosion products. Because these bronze dagger-axes were all unearthed in the tombs, the phosphoric ion in the buried environment should come from hydroxyapatite (Ca5(PO4)3OH) which is the main inorganic phase of human bones and teeth in the tombs.

Post-mortem gross composition changes and differential weathering of immature and mature bone in an experimental burial environment

In addition to differential culture-specific burial practices, the relative absence of juvenile skeletal remains in historic cemetery excavations has been explained by a comparatively rapid breakdown of immature bone. While the idea of differing breakdown rates between immature and mature bone is widely accepted, few experiments have provided evidence to support it.This study uses a porcine model to explore the role of bone maturity with regards to the overall susceptibility of the skeleton to physical and compositional degradation in an experimental buried environment. Samples (n = 104) were mechanically defleshed and left to degrade in a climate-controlled greenhouse environment, buried 10 cm below the soil surface. Every month, for the span of 12 months, 4 immature and 4 mature bones were collected. Weight loss on ignition analysis was performed to determine changes in the composition of bone, and bone weathering analysis was carried out to quantify the physical breakdown of bone.The results of this study indicate that in the first year after skeletonization of buried skeletal remains the compositional and physical breakdown of immature bones differ significantly from the changes seen in their mature bone counterparts. Immature bones seem more susceptible to compositional changes, but less affected by physical surface weathering. How these early differences in degradation affect the long-term survival of bone material and its post-depositional history in archaeological contexts, however, requires a longer study interval.

Geochemistry of the fracture-cave calcite of the Ordovician Yingshan Formation and its paleokarst environment in the Tazhong area, Tarim Basin, China

The fracture-cave reservoir of the Yingshan Formation is an important oil and gas producing zone in the Tarim Basin. Karstification occurs at the top surface of the carbonate rocks of the Yingshan Formation on the northern slope of the Tazhong area due to a short exposure, so abundant fracture-cave spaces are formed. On the basis of the data of nearly 49 samples obtained from 21 wells, the carbon and oxygen isotopes of the fracture-cave calcite were analyzed. The carbon and oxygen stable isotopic characteristics recorded during paleokarstification were discussed to provide geochemical evidence for predicting the distribution of the fracture-cave reservoirs, as well as to understand the genetic mechanism of karst fracture-caves and the fluid properties and paleo-hydrological conditions of paleokarstification. The fracture-cave calcite can be divided into three types based on its carbon and oxygen isotope values, which indicate three types of paleokarst environments with different fluid properties. Type I calcite has similar carbon and oxygen isotope values to the bedrock of the Yingshan Formation, with δ13C values of − 2.0 to 1.1‰ and δ18O values of − 5.76 to − 8.16‰. These values indicate that the calcite was precipitated in the eogenetic karst environment of the Yingshan Formation. Type II calcite has a δ13C value of − 2.13 to 1.0‰ and a δ18O value of − 12.41 to − 8.0‰. It has a similar δ13C value, but a significantly negative oxygen isotope value compared with values of the bedrock of the Yingshan Formation, indicating a buried karst environment. Type III calcite has an extremely negative δ18O value (δ18O value < − 14.50‰), indicating hypothermal karst genesis. Its formation is related to magma or deep hydrothermal fluids. No calcite with atmospheric freshwater genesis and significantly negative δ13C and δ18O values was found in the samples, indicating that the formation of fracture-caves is weakly affected by atmospheric freshwater. The main reservoir space of the Yingshan Formation is karst caves. The calcite in the karst cave fillings belongs to type I, indicating an eogenetic karstification environment. Therefore, the formation of the fracture-cave reservoirs of the Yingshan Formation in the Tazhong area is related to eogenetic karstification, which occurred during exposure and mainly contributed to the formation of the reservoir spaces.

Research on Water Content and Physicochemical Properties of Insulating Materials for Water-Soaked XLPE Cable

The buried environment of cross-linked polyethylene (XPLE) cable is relatively severe, and some ones are even immersed in water directly. In this paper, an XLPE cable was soaked in foul water to simulate the cable’s actual water area environment, lasting for three years. The water content in the insulation layers of water-soaked cable was measured by infrared spectrometer and moisture analyzer, and the crystal morphology and physicochemical properties of the insulation layers were investigated by differential Scanning Calorimeter (DSC), scanning electron microscopy (SEM) and tensile testing technology. The results showed that a small amount of water did enter into the cable insulation owing to the increasing of hydroxyl (-OH) content, and followed being verified by moisture analyzer. The degree of crystallinity of water-soaked cable insulating material is also increased, and the mechanical properties were deteriorated.

Pilot-scale CO2 Sequestration Test Site in the Sulcis Basin (SW Sardinia): Preliminary Site Characterization and Research Program

The deep aquifer located at a depth of about 1000-1500 m within fractured carbonate in the Sulcis coal basin (South-West Sardinia, Italy) constitutes a potential reservoir to develop a pilot-scale CO2 storage site. The site is well known in terms of stratigraphy and structural settings, due to the data available from the coal mining activity. On the basis of these data, a potential deep reservoir and the caprock can be recognized; more in detail, in the southern sector of the basin, the top of the potential reservoir reaches a suitable depth for storage. At the same time, the already existing infrastructures (the Sotacarbo Research Centre on carbon capture, utilization and storage), coupled with some peculiar features (as the low natural seismicity, the hydrogeological system, etc.) makes the Sulcis area a potential experimental site capable to further develop CO2 storage technologies, such as low-cost drilling, site monitoring, and experimental studies on CO2 diffusion and leakage.In this context, Sotacarbo (in cooperation with ENEA, the Universities of Cagliari and Rome “La Sapienza”, OGS, INGV and RSE) is leading a very ambitious research program, funded by both the Italian and the Sardinian Regional Governments within two different and complementary projects, to characterize the Sulcis coal basin as a potential site for the development of CO2 geological storage technologies. The research activities are structured in two different phases: (i) site characterization, including the construction of an underground and a fault laboratories and (ii) the installation of a test site for small-scale injection of CO2. In particular, the underground laboratory will host geochemical and geophysical experiments on rocks, taking advantages of the buried environment and the very well confined conditions in the galleries; in parallel, the fault laboratory will be constructed to study CO2 leakage phenomena in a selected fault.Overall, the project, which is currently ongoing, will allow to characterize the Sulcis basin and to develop a permanent infrastructure (know-how, equipment, laboratories, etc.) for advanced international studies on CO2 storage.This work describes the whole Sulcis CO2 storage project, highlighting its current status, some of the preliminary results of site characterization phase, planned activities and the links with the research activities on carbon capture and utilization.

Deception Island, Antarctica, harbors a diverse assemblage of wood decay fungi

Very little is known about fungal diversity in Antarctica as compared to other biomes and how these important organisms function in this unusual ecosystem. Perhaps one of the most unusual ecosystems is that of Deception Island; an active volcanic island part of the South Shetland Islands of the Antarctic Peninsula. Here we describe the fungal diversity associated with historic wood from structures on the island, which reveals a diverse fungal assemblage of known wood decay fungi as well as the discovery of undescribed species. The major group of wood decay fungi identified were species of Cadophora and as shown in previous studies in other geographic regions of Antarctica, they caused a soft-rot type of decay in the introduced woods. Additionally, unlike other areas of Antarctica that have been studied, filamentous basidiomycetes (Hypochniciellum spp. and Pholiota spp.) were also identified that have different modes of degradation including brown and white rot. Matches of fungal sequences to known species in temperate regions likely introduced on building materials indicates human influences and volcanic activity have greatly impacted fungal diversity. Lahars (mudslides from volcanic activity) have partially buried many of the structures and the buried environment as well as the moist, warm soils provided conditions conducive for fungal growth that are not found in other regions of Antarctica. The diverse assemblage of decay fungi and different forms of wood decomposition add to the difficulty of conserving wooden structures at these important polar heritage sites.

Subsea Cable Tracking by Autonomous Underwater Vehicle with Magnetic Sensing Guidance.

The changes of the seabed environment caused by a natural disaster or human activities dramatically affect the life span of the subsea buried cable. It is essential to track the cable route in order to inspect the condition of the buried cable and protect its surviving seabed environment. The magnetic sensor is instrumental in guiding the remotely-operated vehicle (ROV) to track and inspect the buried cable underseas. In this paper, a novel framework integrating the underwater cable localization method with the magnetic guidance and control algorithm is proposed, in order to enable the automatic cable tracking by a three-degrees-of-freedom (3-DOF) under-actuated autonomous underwater vehicle (AUV) without human beings in the loop. The work relies on the passive magnetic sensing method to localize the subsea cable by using two tri-axial magnetometers, and a new analytic formulation is presented to compute the heading deviation, horizontal offset and buried depth of the cable. With the magnetic localization, the cable tracking and inspection mission is elaborately constructed as a straight-line path following control problem in the horizontal plane. A dedicated magnetic line-of-sight (LOS) guidance is built based on the relative geometric relationship between the vehicle and the cable, and the feedback linearizing technique is adopted to design a simplified cable tracking controller considering the side-slip effects, such that the under-actuated vehicle is able to move towards the subsea cable and then inspect its buried environment, which further guides the environmental protection of the cable by setting prohibited fishing/anchoring zones and increasing the buried depth. Finally, numerical simulation results show the effectiveness of the proposed magnetic guidance and control algorithm on the envisioned subsea cable tracking and the potential protection of the seabed environment along the cable route.

Exploring the Nature of the Nanocavity and Channels in Apoferritin and Apoferritin–Sodium Dodecyl Sulfate Complex Using an Enhanced Antenna Effect through the Encapsulation of EuIII–Tetracycline

The drug tetracycline hydrochloride (TC), which has cytotoxic and cytostatic effects on tumor cells, has been encapsulated within the nanocavity of apoferritin in the form of its EuIII complex (Eu3TC). The Eu3TC complex was encapsulated within apoferritin through disassembly followed by reassembly of the protein and exhibited significantly enhanced EuIII emission in comparison with that of free Eu3TC in aqueous buffer at pH 8. The steady‐state and transient measurement of the emission of each species in the ternary system suggest that the effective sensitization of EuIII emission may be ascribed to a comparatively rigid environment for the bound TC after encapsulation that promotes efficient energy transfer to the EuIII ions. Emission studies in D2O revealed that the microenvironment of the EuIII ion is shielded from O–H oscillators in the ternary system, and the extent of shielding is greater after the encapsulation of the complex within the apoferritin cavity. The rotational correlation time (θc) of bound TC and docking studies also support the contention that the TC is in a more buried environment after encapsulation within the apoferritin cavity. A competition study with sodium dodecyl sulfate (SDS) revealed that SDS does not interfere with the binding of TC to apoferritin. The biocompatible system consisting of Eu3TC encapsulated within the cavity of apoferritin may be used as an efficient targeted drug transporter, and the sensitization of the EuIII emission may also enable its use as a biosensor.

风化壳古岩溶型碳酸盐岩储层成岩作用与成岩相

Abstract In the north of the Jingbian Gas Field in the Ordos Basin, a case study was made of the first section of the fourth sub-member of the fifth member of the Majiagou Formation (M51 4). Through detailed subsurface geological analysis, a realistic description of typical diagenetic features, systematic sampling and laboratory testing, with geological background and petrological characteristics as main clue, the diagenesis characteristics of crust-weathered ancient karst carbonate reservoirs were analyzed, and the diagenetic facies were recognized. The marine diagenetic environment of M51 4 was influenced by dolomitization and anhydritization, and was controlled by the palaeogeographic framework. As to the epidiagenetic environment controlled by ancient karst physiognomy, dissolution and packing effects of dissolved pore, fracture and cave types took place. For the buried diagenetic environment, extensive dissolution was common. Based on the coupling relationship between diagenesis and porosity-permeability network, a “diagenesis in marine diagenetic environment + diagenesis in epidiagenetic environment” combination principle was adopted to divide the diagenetic facies into four typical types: (I) medium-weak filling facies of anhydrite small nodule dolomitization-dissolved pore and fracture type; (II) medium-strong filling facies of anhydrite small nodule dolomitization-dissolved pore and fracture type; (III) strong filling facies of dolomitization-dissolved cave type; and (IV) strong filling facies of anhydrite lithification-dissolved pore and fracture type, and strong filling facies of dissolved cave type. With well-developed premium reservoir rocks, moderate karst intensity and medium-weak (deposition) filling, the type-I area was favorable for fracture-cave reservoir development