Sequence Stratigraphy of Fine-Grained “Shale” Deposits: Case Studies of Representative Shales in the USA and China

The fine-grained “shale” deposits host a vast amount of unconventional oil and gas resources. This chapter examines the variations in lithofacies, patterns of well logs, geochemistry, and mineralogy in order to construct a sequence stratigraphic framework of the representative marine Barnett, Woodford, Marcellus, Mowry, and Niobrara fine-grained “shales” (USA) and the marine Longmaxi shale and lacustrine Chang7 lacustrine shale (China). Practical methods are proposed in order to recognize the sequence boundaries, the flooding surfaces, the parasequences and parasequence sets, the system tracts, and variation patterns of facies and rock properties. The case studies for the sequence stratigraphy in the USA and China have revealed that the transgressive systems tract (TST) and the early highstand systems tract (EHST, if identifiable) of fine-grained “shales” have been deposited in anoxic settings. TST and EHST of the siliciclastic “shales” are characterized by high gamma ray, high TOC, and high quartz content, while TST and EHST of the carbonate-dominated fine-grained “shales” are characterized by low gamma ray, organic lean, and carbonate rich fine-grained deposits. The lithofacies, geochemistry, mineralogy, depositional evolution, and reservoir development have been predicted and correlated within a sequence stratigraphic framework for the suggested cases. The best reservoir with the best completion quality is developed in TST and HST in both siliciclastic-dominated and carbonate-dominated fine-grained “shales.

Discrepancies in resistant starch and starch physicochemical properties between rice mutants similar in high amylose content

The content of resistant starch (RS) was considered positively correlated with the apparent amylose content (AAC). Here, we analyzed two Indica rice mutants, RS111 and Zhedagaozhi 1B, similar in high AAC and found that their RS content differed remarkably. RS111 had higher RS3 content but lower RS2 content than Zhedagaozhi 1B; correspondingly, cooked RS111 showed slower digestibility. RS111 had smaller irregular and oval starch granules when compared with Zhedagaozhi 1B and the wild type. Zhedagaozhi 1B showed a B-type starch pattern, different from RS111 and the wild type, which showed A-type starch. Meantime, RS111 had more fa and fb1 but less fb3 than Zhedagaozhi 1B. Both mutants showed decreased viscosity and swelling power when compared with the parents. RS111 had the lowest viscosity, and Zhedagaozhi 1B had the smallest swelling power. The different fine structures of amylopectin between RS111 and Zhedagaozhi 1B led to different starch types, gelatinization properties, paste viscosity, and digestibility. In addition to enhancing amylose content, modifications on amylopectin structure showed great potent in breeding rice with different RS2 and RS3 content, which could meet the increasing needs for various rice germplasms

Advantageous shale lithofacies of Wufeng Formation-Longmaxi Formation in Fuling gas field of Sichuan Basin, SW China

The lithofacies types of Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation shale, the main producing layer in Fuling gas field, are classified in detail using the modified ternary diagram of siliceous minerals-carbonates minerals-clay minerals. There develop eight lithofacies in the Wufeng-Longmaxi shale: siliceous shale lithofacies (S), mixed siliceous shale lithofacies (S-2), clay-rich siliceous shale lithofacies (S-3), calcareous/siliceous mixed shale lithofacies (M-1), argillaceous/siliceous mixed shale lithofacies (M-2), mixed shale lithofacies (M), silica-rich argillaceous shale lithofacies (CM-1), and argillaceous/calcareous mixed shale lithofacies (M-3). The advantageous shale lithofacies is defined as lithofacies with gas content reaching a specific industrial standard. Based on the current development status of the study area, advantageous shale lithofacies is divided into two classes, namely, Class I with gas content of more than 4.0 m3/t (also known as extra superior), Class II with gas content of 2.0−4.0 m3/t (also known as superior). The correlation between the abundance of organic matter, the content of siliceous mineral, clay content and gas content has been analyzed to establish the classification criteria for advantageous shale lithofacies in the Wufeng-Longmaxi shale. The mixed siliceous shale lithofacies (S-2) and clay-rich siliceous shale lithofacies (S-3) have been identified as Class I advantageous shale lithofacies, and argillaceous/siliceous mixed shale lithofacies (M-2) as Class II. The classification criteria of advantageous shale lithofacies can provide reference for shale gas evaluation in other exploration areas Key words: shale, advantageous shale lithofacies, Ordovician Wufeng Formation, Silurian Longmaxi Formation, Fuling gas field, Sichuan Basi

Effects of volcanic activities in Ordovician Wufeng–Silurian Longmaxi period on organic-rich shale in the Upper Yangtze area, South China

Based on the corresponding relationship between the paleoproductivity, redox conditions and volcanism within a chronostratigraphic framework, the effects of volcanic events in the Wufeng–Longmaxi period on organic abundance of shale were examined. Bentonite layers were mostly developed in the transgressive systems tract 1 (TST1, Wufeng Formation) and transgressive systems tract 2 (TST2, Longmaxi Formation), and the two systems tracts corresponded to favorite shale lithofacies with high silica and total organic carbon (TOC) contents. According to the stratigraphic characteristics of bentonite rich interval, TST1 is classified as the interval with dense bentonite layers with the frequency of bentonite layer (bentonite layers/time) of more than 1.5 layers/Ma and the cumulative thickness ratio of bentonite layers (thickness of bentonite layers/thickness of shale) of more than 1%; TST2 is classified as the interval with sparse bentonite layers (frequency < 1.5 layers/Ma; cumulative thickness ratio < 1%). TST1 (dense interval) witnessed more intense and high-frequency volcanic activities than TST2 (sparse interval), so the TST1 has generally higher TOC than TST2. The intense and frequent volcanic activities had dual effects on organic-rich shale: on one hand, volcanic ash provided a sufficient supply of nutrients, which triggered high marine productivity; on the other hand, the extremely anoxic environment caused by volcanic activity enhanced the burial amount and preservation rate of organic matter. Key words: shale, organic abundance, volcanism, sequence stratigraphy, Ordovician Wufeng Formation, Silurian Longmaxi Formation, Upper Yangtze area, bentonit

Defining Exposure Predictors of Meropenem That Are Associated with Improved Survival for Severe Bacterial Infection: A Preclinical PK/PD Study in Sepsis Rat Model

Background: The pharmacokinetic/pharmacodynamic (PK/PD) index of carbapenems that best correlates with in vivo antimicrobial activity is percent time of dosing interval in which free drug concentration remains above MIC (%fT &gt; MIC), while the magnitudes of the PK/PD index of carbapenems remains undefined in critically ill sepsis patients. Methods: A sepsis rat model was first developed by comparing the survival outcomes after intraperitoneal injection of different inoculum size (1&ndash;10 &times; 107 CFU) of Pseudomonas aeruginosa ATCC9027 (MIC = 0.125 mg/L) in neutropenic rats. The PK characteristics of the model drug meropenem in the developed sepsis rat model was then evaluated, and PK modeling and simulation was applied to design meropenem dosing regimens attaining various PD targets (40%fT &gt; MIC, 100%fT &gt; MIC, and 100%fT &gt; 4 &times; MIC). The microbiological response and survival outcomes for different meropenem treatment regimens were investigated in the rat sepsis model (n = 12 for each group). Results: The optimal inoculum for the rat sepsis model was 1 &times; 107 CFU of Pseudomonas aeruginosa ATCC9027. A one-compartment model with first-order absorption best described the PK of meropenem in sepsis rats. Pronounced survival prolongation and lower hazard risk were observed in the treatment groups of 50 or 75 mg/kg/q2.4h (100%fT &gt; MIC) and 75 mg/kg/q2h (100%fT &gt; 4 &times; MIC) compared to the 75 mg/kg/q6h (40%fT &gt; MIC) group, while meropenem groups with PD targets of 100%fT &gt; MIC and 100%fT &gt; 4 &times; MIC showed comparable survival curves. Microbiological response for different PD targets is inconclusive due to irregular bacterial counts in blood samples. Conclusions: The PD target of 40%fT &gt; MIC is suboptimal for sepsis rats, and the aggressive 100%fT &gt; 4 &times; MIC target does not provide a survival benefit against the target of 100%fT &gt; MIC

Cross-Layer Feature Fusion and Decentration Aberration Correction of Circular Points for Automated Guided Vehicle Terminal Positioning

To address the visual detection and positioning challenge of the Automated Guided Vehicle (AGV) terminal, this study proposed a high-precision target recognition and positioning strategy based on cross-layer feature fusion and eccentricity error correction. In the remote coarse positioning stage, small number of receiver domains underwent continuous multi-layer convolution, which broadened the receptive field of a single element in the feature map of a small circular target. Next, a cross-layer connection feature pyramid was constructed, and the deconvolution module was utilized to enlarge the feature map and fuse it with the shallow features, focusing more on the fine-grained image recognition and enhancing the applicability of circular marker detection. In the near-end fine positioning stage, the factors impacting the deviation between the projection point of the circular feature center and the fitting center were analyzed. Based on this analysis, the deviation of the iterative fitting center was corrected to approximate the real center projection sub-pixel coordinates. The experimental results demonstrated that the proposed method achieved dynamic positioning accuracy of better than 2.0 mm, static positioning accuracy of better than 1.5 mm, and a false recognition rate of less than 1.33&#x0025; in the range of 3 m from AGV to the tray. Consequently, this method has significant application potential in enabling rapid and stable terminal vision positioning

The Impact of Colonoscopy Quality Control Table on Adenoma Detection Rates

Objective. This study aims to investigate the effects of reporting colonoscopy findings and the regular review of outcomes on adenoma detection rates. Methods. Patients who underwent colonoscopy from August 2013 to February 2014 were selected as the intervention group. The preintervention group included patients who underwent colonoscopy from January 2013 to July 2013, in which the procedure sheet for this group of patients was not accomplished. The primary outcome was adenoma detection rate (ADR), and secondary outcomes included the success rate of intubation and withdrawal time. Results. This study included 2,467 cases: 1,302 cases in the intervention group and 1,165 cases in the preintervention group. There was no significant difference in demographic characteristics between the two groups. In the intervention group, withdrawal time of colonoscopy was longer (P<0.01), and the success rate of intubation (92.5% versus 89.1%, P<0.05) and detection rate of polyps (32.6% versus 27.6%, P<0.05) and adenomas (20.0% versus 16.1%, P<0.05) were higher. Significantly high detection rates for proximal adenomas, flat adenomas, and adenomas with a diameter <5 mm were observed in the intervention group (all P<0.01). Conclusion. The reporting and review of procedure details help to improve quality indicators of colonoscopy

The Impact of Colonoscopy Quality Control Table on Adenoma Detection Rates

Objective. This study aims to investigate the effects of reporting colonoscopy findings and the regular review of outcomes on adenoma detection rates. Methods. Patients who underwent colonoscopy from August 2013 to February 2014 were selected as the intervention group. The preintervention group included patients who underwent colonoscopy from January 2013 to July 2013, in which the procedure sheet for this group of patients was not accomplished. The primary outcome was adenoma detection rate (ADR), and secondary outcomes included the success rate of intubation and withdrawal time. Results. This study included 2,467 cases: 1,302 cases in the intervention group and 1,165 cases in the preintervention group. There was no significant difference in demographic characteristics between the two groups. In the intervention group, withdrawal time of colonoscopy was longer (P<0.01), and the success rate of intubation (92.5% versus 89.1%, P<0.05) and detection rate of polyps (32.6% versus 27.6%, P<0.05) and adenomas (20.0% versus 16.1%, P<0.05) were higher. Significantly high detection rates for proximal adenomas, flat adenomas, and adenomas with a diameter <5 mm were observed in the intervention group (all P<0.01). Conclusion. The reporting and review of procedure details help to improve quality indicators of colonoscopy

Rational design of a structural and functional nitric oxide reductase

Protein design provides a rigorous test of our knowledge about proteins and allows the creation of novel enzymes for biotechnological applications. Whereas progress has been made in designing proteins that mimic native proteins structurally, it is more difficult to design functional proteins. In comparison to recent successes in designing non-metalloproteins, it is even more challenging to rationally design metalloproteins that reproduce both the structure and function of native metalloenzymes. This is because protein metal-binding sites are much more varied than non-metal-containing sites, in terms of different metal ion oxidation states, preferred geometry and metal ion ligand donor sets. Because of their variability, it has been difficult to predict metal-binding site properties in silico, as many of the parameters, such as force fields, are ill-defined. Therefore, the successful design of a structural and functional metalloprotein would greatly advance the field of protein design and our understanding of enzymes. Here we report a successful, rational design of a structural and functional model of a metalloprotein, nitric oxide reductase (NOR), by introducing three histidines and one glutamate, predicted as ligands in the active site of NOR, into the distal pocket of myoglobin. A crystal structure of the designed protein confirms that the minimized computer model contains a haem/non-haem Fe B centre that is remarkably similar to that in the crystal structure. This designed protein also exhibits NO reduction activity, and so models both the structure and function of NOR, offering insight that the active site glutamate is required for both iron binding and activity. These results show that structural and functional metalloproteins can be rationally designed in silico. © 2009 Macmillan Publishers Limited. All rights reserved