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Multisubstituted alkenes are accessible by a gold-catalyzed acyloxyalkynylation of ynamides with ethynylbenziodoxolones (EBXs) with perfect atom-economy. The EBX reagents transfer both the carboxylate as well as the alkynyl entity. Overall, this cascade comprises the in situ generation of an alkynyl gold(III) species, a stereoselective C(sp)-C(sp

Glycerol hydrogenated rosin (GEHR) and d-limonene were prepared for micro-particles by electrostatic spray method. When the GEHR/d-limonene ratio is 5.5:4.5 and the electrostatic spray extrusion speed is 1 mL/h, the best particle size (177.24 ± 17.09 μm) and embedding rate of d-limonene (41.74 ± 9.88%) are achieved. Then, rock bean protein (RP) was extracted from wild rock beans and combined with GEHR/d-limonene particles and corn starch (CS) to prepare a new type of edible film. The prepared film was characterized using Fourier transform infrared spectroscopy in terms of structural changes and physical, optical, mechanical, and thermal properties. The results show that the edible film with a ratio of 1:1 exhibited more optimized thermal (179.2 °C) and mechanical properties (TS 0.88 MPa, EAB 54.36%). Studies on freshly prepared glutinous rice cake as an object for preservation using edible film show that the films can prolong shelf life by ~2-4 d. Through this experiment, it can serve as a reference for the development of a new type of edible film.

Soybean functional peptides (SFPs) are obtained via the hydrolysis of soybean protein into polypeptides, oligopeptides, and a small amount of amino acids. They have nutritional value and a variety of functional properties, including regulating blood lipids, lowering blood pressure, anti-diabetes, anti-oxidant, preventing COVID-19, etc. SFPs have potential application prospects in food processing, functional food development, clinical medicine, infant milk powder, special medical formulations, among others. However, bitter peptides containing relatively more hydrophobic amino acids can be formed during the production of SFPs, seriously restricting the application of SFPs. High-quality confirmatory human trials are needed to determine effective doses, potential risks, and mechanisms of action, especially as dietary supplements and special medical formulations. Therefore, the physiological activities and potential risks of soybean polypeptides are summarized, and the existing debitterness technologies and their applicability are reviewed. The technical challenges and research areas to be addressed in optimizing debittering process parameters and improving the applicability of SFPs are discussed, including integrating various technologies to obtain higher quality functional peptides, which will facilitate further exploration of physiological mechanism, metabolic pathway, tolerance, bioavailability, and potential hazards of SFPs. This review can help promote the value of SFPs and the development of the soybean industry.

The Amazon sailfin catfish (Pterygoplichthys pardalis), which belongs to the Loricariidae family, is an invasive species that has caused massive damage to the ecological environment. However, a high-quality reference genome for this catfish species has not yet been reported. Here, we successfully assembled the first chromosome-level high-quality genome of P. pardalis using data produced from multiple sequencing platforms. The assembled genome contains 26 chromosomes, with a scaffold N50 of 49.47 Mb. Different evaluation methods indicated the high connectivity and accuracy genome we got. In total, 23 859 protein-coding genes were predicted in the genome, 22 169 (92.92%) of which were functionally annotated in public databases. Phylogenetic analysis showed that P. pardalis was clustered with all other catfish studied and diverged from their common ancestor 132.5 million years ago. Whole-genome collinearity analysis indicated the chromosome 6 of P. pardalis was aligned to two distinct chromosomes in Ameiurus melas, Pangasianodon hypophthalmus, and Ictalurus punctatus, suggesting the occurrence of potential chromosomal fusion/fission events. Furthermore, many immune system-related genes were expanded in the P. pardalis genome, which may have contributed to their adaptive traits to highly polluted environments and successful invasion. This study not only provides insights into the genetic basis of the successful invasion of P. pardalis, but also provides important data for comparative genomic analysis of P. pardalis in Siluriformes in the future.

Background Food packaging is a globally relevant and widely used technique for food preservation. Natural, biodegradable, and bioavailable polymers are gaining popularity in the field of food packaging. Cellulose and its derivatives are amongst the most abundant and widely used polymers in the packaging industry. There are many natural sources for cellulose, and they can also be obtained from bio-wastes and agricultural wastes. Thus, it is available in large quality and is cost effective. Scope and approach In this review, we discussed the importance, functioning, properties, and characteristics of cellulose and its derivatives for food packaging. The application of cellulose in food packaging from the discovery of cellulose in 1839–2020 was introduced in this article. Which includes its use for the preservation of fruits and vegetables is discussed in detail, and its application as carrier of various natural antibacterial and antioxidant compounds was introduced. Various types of composite films prepared using cellulose and its derivatives are also discussed in this review. Furthermore, numerous functional properties of cellulose have been mentioned. Key findings and conclusion Cellulose is one of the most important polymers in the food industry. This study explores its properties and its encapsulations and stabilization of compounds without altering their properties. Through extensive study of existing literature on the subject, this review compiles the information relevant to the use of cellulose in food preservation. In addition, various future considerations are further presented.

Background Food safety and spoilage prevention are the main concerns in the food packaging industry. Microbial contamination is one of the biggest causes of food deterioration and may occur immediately after harvesting. Therefore, there is an increased demand for antimicrobial food packaging. Active packaging carries active compounds, such as antimicrobial peptides (AMPs), encapsulating them in various nanocarriers to ensure their controlled release for food preservation during storage. AMPs have gained increased attention in recent years as potential ingredients in packaging, as they demonstrate a broad range of antimicrobial and immunomodulatory activities against foodborne pathogens and infectious bacteria. Scope and approach This review will describe AMPs and their use in the food packaging industry along with their characteristics, functions, properties, types, and mechanisms of action in active food packaging systems. The encapsulation of AMPs is also highlighted. Key findings and conclusion AMPs have potential applications in the food packaging industry. They are used in very small amounts and can exert notable effects against microbial growth and contamination. They also reduce lipid oxidation in various meat products. Moreover, active packaging is a promising technique to incorporate carry microcapsules and nano-encapsulated structures with AMPs as the core to ensure their sustained release upon various triggers. These characteristics depend on the type of AMPs and their effectiveness. Various strategies can be developed to enable cost-effective and efficient AMP encapsulation techniques. There is a great need to evaluate and utilize the potential of AMPs improved food preservation.

Polylactic acid (PLA)/nano-TiO2(TiO2 NPs)/Graphene oxide (GO) nano-fibrous films were prepared by ultrasonic assisted electrostatic spinning technology, and the effects of TiO2 NPs:GO mass ratio and ultrasonic power on film morphology and mechanical, thermal, barrier and antibacterial properties were investigated. The addition of TiO2 NPs and GO can significantly increase the tensile strength and elongation at the break of PLA nano-fibrous films, and improve the water barrier properties of the nano-fibrous films. The antibacterial experiment showed that the inhibition rates of the nano-fibrous films against Escherichia coli and Staphylococcus aureus after 24 h exposure to UV irradiation reached 94.4 ± 1.8% and 92.6 ± 1.7% At the same time, the fresh-keeping packaging experiment of green peppers at room temperature, through the determination of hardness, soluble solids, chlorophyll content to determine the degree of decay of green pepper, it showed that PLA/TiO2 NPs/GO nano-fibrous films can better maintain the sensory quality of green peppers, delay the rate of spoilage of green peppers, and prolong the preservation period of green peppers.

Food safety is a bottleneck problem. In order to provide information about advanced and unique food packaging technique, this study summarized the advancements of electrospinning technique. Food packaging is a multidisciplinary area involving food science, food engineering, food chemistry, and food microbiology, and the interest in maintaining the freshness and quality of foods has grown considerably. For this purpose, electrospinning technology has gained much attention due to its unique functions and superior processing. Sudden advancements of electrospinning have been rapidly incorporated into research. This review summarized some latest information about food packaging and different materials used for the packaging of various foods such as fruits, vegetables, meat, and processed items. Also, the use of electrospinning and materials used for the formation of nanofibers are discussed in detail. However, in food industry, the application of electrospun nanofibers is still in its infancy. In this study, different parameters, structures of nanofibers, features and fundamental properties are described briefly, while polymers fabricated through electrospinning with advances in food packaging films are described in detail. Moreover, this comprehensive review focuses on the polymers used for the electrospinning of nanofibers as packaging films and their applications for variety of foods. This will be a valuable source of information for researchers studying various polymers for electrospinning for application in the food packaging industry.

The aim of our study was to compare overfeeding performance, fatty acid composition, enzymes activity and gene expression between overfed Xupu geese with large and small liver. A total of sixty 80 d male Xupu geese were overfed by the same feed intake under the same conditions. The liver weight exhibited normal distribution. Based on the weight of liver, samples were divided into large liver (LL) and small liver (SL) Xupu geese. After overfeeding for 28 d: compared with the SL-Xupu geese, liver weight and liver-to-body weight ratio increased (p

A gold-catalysed cascade C(sp3)–H alkynylation/oxy-alkynylation of acceptor-substituted carbonyl compounds with hypervalent iodine(III) reagents for the synthesis of tetra-substituted furans is described. This reaction involves two Au(I)/Au(III) catalytic cycles and proceeds through a C(sp3)–H alkynylation of a substituted ketone and a subsequent oxy-alkynylation of the generated 2-alkynyl ketone. This mild and simple method can tolerate a wide range of functionalities, offering distinct advantages over previous methods using PIDA as the external oxidant. Furthermore, a gram-scale synthesis is feasible and the synthesized furan product was readily transformed into other related compounds.

In this study, chitosan/halloysite nanotubes/tea polyphenol (CS/HNTs/TP) nanocomposite films were prepared by the solution casting method. The scanning electron microscopy (SEM) result showed that the nanocomposite film with a CS/HNTs ratio of 6:4 and a TP content of 10% (C6H4-TP10) had a relatively smooth surface and a dense internal structure. The water vapor barrier property of the nanocomposite film was improved due to the tortuous channels formed by the HNTs. However, the swelling degree and water solubility of the nanocomposite films were decreased. The nanocomposite films have a good antioxidant capacity. Antibacterial experiments showed that the C6H4-TP10 nanocomposite film had certain inhibitory effects on the growth of both E. coli and S. aureus. In addition, we used 3D printer to verify the printability of the optimal formulation of the film-forming solution. Overall, this strategy provides a simple approach to construct promising natural antioxidants and antibacterial food packaging.

In this study, we compared the incidence of postharvest disease and the storage potential of blueberry fruit treated with thymol (inoculated with Aspergillus niger) with those in the control fruit during storage for 42 d at 2 °C. Treatment with 10-30 mg/L thymol was found to be more effective than treatment with higher thymol concentrations of 40-50 mg/L in terms of controlling Aspergillus niger-induced decay. In the thymol-treated blueberry fruit peel, the activities of the disease resistance-related enzymes were significantly enhanced. Furthermore, the 20 mg/L thymol-treated blueberry fruit retained the highest firmness, total soluble solids content, and acceptability score, and it also maintained an unimpaired cell wall structure of pericarp quality. Thus, low-dose thymol-treatment could be a suitable biocontrol agent for controlling postharvest disease and prolonging the storage life of blueberry fruit.

In this study, lemongrass essential oil (LEO) was wrapped in β-cyclodextrin (β-CD) using a co-precipitation method to prepare an inclusion complex (LEO/β-CD). A biological multifunctional preservation card was prepared by 3D printing and mixing the inclusion complex with sodium alginate (SA). The moisture generated by strawberry respiration melted the popping candy (PPC) and stimulated the release of CO

Perpendicularly magnetized structures that are switchable using a spin current under field-free conditions can potentially be applied in spin-orbit torque magnetic random-access memory (SOT-MRAM). Several structures have been developed; however, new structures with a simple stack structure and MRAM compatibility are urgently needed. Herein, a typical structure in a perpendicular spin-transfer torque MRAM, the Pt/Co multilayer and its synthetic antiferromagnetic counterpart with perpendicular magnetic anisotropy, was observed to possess an intrinsic interlayer chiral interaction between neighboring magnetic layers, namely, the interlayer Dzyaloshinskii-Moriya interaction (DMI) effect. Furthermore, using a current parallel to the eigenvector of the interlayer DMI, we switched the perpendicular magnetization of both structures without a magnetic field, owing to the additional symmetry breaking introduced by the interlayer DMI. This SOT switching scheme realized in the Pt/Co multilayer and its synthetic antiferromagnet structure may open a new avenue toward practical perpendicular SOT-MRAM and other SOT devices.

Silk fibroin (SF) is a promising biomaterial for tendon repair, but its relatively rigid mechanical properties and low cell affinity have limited its usefulness and utility in regenerative medicine. Meanwhile, gelatin-based polymers have advantages in cell attachment and tissue remodeling, but have insufficient mechanical strength to regenerate tough tissue such as tendons. Taking these aspects into account, in this study, gelatin methacryloyl (GelMA) was combined with SF to create a mechanically strong and bioactive nanofibrous scaffold (SG). The mechanical properties of SG nanofibers could be flexibly modulated by varying the ratio of SF and GelMA. Compared to SF nanofibers, mesenchymal stem cells (MSCs) seeded on SG fibers with optimal composition (SG7) exhibited enhanced growth, proliferation, vascular endothelial growth factor (VEGF) production and tenogenic gene expression behavior. Conditioned media from MSCs cultured on SG7 scaffolds, compared to MSCs cultured on SF or GelMA alone nanofibers could greatly promote the migration and proliferation of tenocytes. Histological analysis and tenogenesis related immunofluorescence staining indicated SG7 scaffolds demonstrated enhanced in vivo tendon tissue regeneration compared to other groups. Therefore, rational combinations of SF and GelMA hybrid nanofibers may help to improve therapeutic outcomes and address the challenges of tissue-engineered scaffolds for tendon regeneration.

In this study, lycopene microcapsules (LMs) were prepared using chitosan (CS) and carboxymethyl CS (CMCS) as the wall materials. Sodium alginate (SA) and konjac glucomannan (KGM) were used as substrates to fabricate LM/SA/KGM composite films. Results showed that when 2.0 % CMCS was employed, the resulting LMs had the maximum embedding rate of 83.17 %, smallest particle sizes, and stable zeta potentials. The LMs still had a high retention rate after 10 days of storage at 4 and 25 °C. When 2.0 % LMs were used, the corresponding composite film exhibited the best antibacterial properties, oxidation resistance, a high transparency (82.3 %), and a strong water vapor barrier (2.39 × 10

Microbial contamination is an utmost cause of food spoilage. Antimicrobial agents are used to treat microbial diseases in food. They also serve food packaging industry, as they are used for the formation of antimicrobial packaging films which maintain the structure, texture, color, and nutrition value of food. Due to ever growing population, the demands of food are also rising. There is need to stop food wastage and to prevent spoilage. Most of the food is spoiled during harvesting, transportation, and distribution. This is a serious problem to overcome. Adding antibacterial agents is the most convenient way to reduce food spoilage and contamination. To support the characteristics and properties of antibacterial materials, different modifications are performed in the field of food packaging, which is one of the most demanding techniques for food preservation. This review will summarize the research about antimicrobial agents, with an emphasis on recent findings, to highlight the importance of new developments in this field. Concepts of antimicrobial packaging with a focus on antibiotics and antibacterial agents are discussed briefly in this review, along with the different types of food packaging and applications of antimicrobial packaging. Synthetic and natural antimicrobial materials are described. In summary, this article will explain the importance of antibacterial agents and their use in food packaging industry. Furthermore, readers will get good information about natural antibacterial polymers which were extensively used in past few decades. Subsequently, different innovations should be done to control food spoilage and wastage to ensure food safety. Food packaging is a sole element that helps to provide safe and secure food for all.

Encapsulation effectively delays the volatilization of lemon essential oil (LEO). Here, various chitosan (CS)-LEO nanoparticles were prepared by emulsification using different CS and Tween-80 concentrations and CS:TPP and CS:LEO ratios. The CS-LEO nanoparticles were spherical, small in size (58 ± 9 nm), had a low polydispersity index (0.15), and were highly stable under the right conditions. FTIR spectra indicated that they were fully encapsulated in the films. The composite films are characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscope (SEM) and X-ray diffraction (XRD). Relative to grass carp collagen (GCC) films, edible GCC/CS-LEO had lower oxygen permeability (OP), higher tensile strength (TS), and higher elongation at break (EB). The LEO release rate increased with decreasing GCC:CS-LEO ratio. At GCC:CS-LEO ratio = 7:3, a maximum LEO release rate of 83.6 ± 9.7% was achieved over 15 days. GCC/CS-LEO films can effectively inhibit lipid oxidation, prevent microbial proliferation, and delay the deterioration of pork at 4 °C for 21 days.

Fluorescent nanomaterials have been widely used in biological imaging due to their selectivity, sensitivity, and noninvasive nature. These characteristics make the materials suitable for real-time and in situ imaging. However, further development of highly biocompatible nanosystems with long-lasting fluorescent intensity and photostability is needed for advanced bioimaging. We have used electrospraying to generate gelatin methacryloyl (GelMA)-based fluorescent nanoparticles (NPs) with chemically conjugated rhodamine B (RB). The extent of conjugation can be controlled by varying the mass ratio of RB and GelMA precursors to obtain RB-conjugated GelMA (RB-GelMA) NPs with optimal fluorescent properties and particle size. These NPs exhibited superior biocompatibility when compared with pure RB in in vitro cell viability and proliferation assays using multiple cell types. Moreover, RB-GelMA NPs showed enhanced cell internalization and improved brightness compared with unconjugated RB. Our experiments demonstrate that engineered RB-GelMA NPs can be used as a biocompatible fluorescent label for bioimaging.

This paper presents a comprehensive investigation of the effects of cutting parameters on the surface integrity of milled γ-TiAl alloys. Surface topography, surface roughness, surface defects, plastic deformation, micro-hardness, chip morphology, and tool wear of the milled γ-TiAl alloys were analyzed. The results indicate that the feed rate had the greatest influence on the surface topography and surface roughness. The value of surface roughness increased with the increase in cutting depth and feed rate. However, with the increase in cutting speed, it initially increased and then decreased. The minimum surface roughness was found to be 0.066 μm. The thickness of the plastic deformation layer and the micro-hardness value increased with the increase in cutting depth and feed rate. Also, they initially increased and then decreased with the increase in cutting speed. The minimum thickness of the plastic deformation layer was 15 μm and the depth of the hardened layer on the processed surface varied between 55 and 70 μm. The chip morphology was closely related to the quality of the processed surface. When the cutting depth and feed rate decreased, the chip morphology was transformed from segmented to nearly smooth. When the cutting depth and feed rate reached a critical point, plastic processing of γ-TiAl was achieved. Compared to brittle deformation, a more favorable processed surface was obtained. Finally, the comparison tests of tool wear were carried out with dry and flood coolant cutting. When the cutting speed reached 120 m/min in dry cutting, the tool life was very poor, and the cutting distance was only 1 m. However, the tool life was generally good when cutting with low cutting speed under the following conditions: vc = 60 m/min, ap = 0.1 mm, and fz = 0.01 mm/tooth. Under these conditions, the cutting distance was 60 m in dry cutting with the tool wear of 0.2 mm and 120 m in flood coolant cutting with the tool wear of 0.1 mm. The tool life in flood coolant operation was better than that of dry operation. The tool life decreased to 30 m when cutting with high cutting speed or feed rate (ap = 0.25 mm or fz = 0.025 mm/tooth).

Smart devices, as the most widely used platforms for the mobile cyber–physical system (CPS) applications, such as smart home and health care systems, are becoming the prime targets of various attackers for users’ considerable private and confidential data in them. To fight against side channel attacks aiming to obtain credentials, e.g., passwords, during the process of user authentication, touch pattern based implicit authentication has been proposed. However, such a defensive technique fails to obtain an entire pattern of user operation by deriving user operation data via a touch-enabled screen. Considering that user operations, including on-screen and in-air finger movements, are performed in three-dimensional (3D) space, we propose a novel 3D magnetic finger motion pattern based implicit authentication technique, referred to as FingerAuth. To use FingerAuth, a user operates on her mobile device, e.g., texting a message and browsing websites, with a magnetic ring on the finger she uses. With the help of a built-in three-axis magnetometer on the mobile device, we can derive the 3D magnetic finger motion pattern as a human behavioral feature for implicitly authenticating the user. By using machine learning techniques, a robust 3D magnetic finger motion pattern detection model can be constructed. Two rounds of usability tests are conducted for the evaluation of FingerAuth. In the initial usability test targeting a given group of smart device users, we test the uniqueness of the proposed trait in typing scenario, achieving high average accuracy of 96.38%, low average false acceptance rate (FAR) of 4.06%, and false rejection rate (FRR) of 3.18%. In the second user usability test, we further evaluate the permanence of 3D finger motion pattern in multiple user–device interaction scenarios. There is an interim of two-week period between the training data collection phase and the testing data collection phase. The results of the high accuracy of over 80%, as well as the FAR and FRR of below 15%, indicate the applicability of FingerAuth.

Expired fruits have always been treated as garbage. In this paper, expired passion fruit shells are processed into carbon quantum dots (CQDs) by hydrothermal synthesis method. Expired passion fruit shells based carbon quantum dots were characterized using TEM-EDS, FTIR, PL, XRD, XPS, Raman spectrum and Uv–vis analysis. The morphology of CQDs shows sphere shape with the size below 5 nm. CQDs exhibit a weak graphite phase structure according to Raman spectrum. The photoluminescence of CQDs shows the obvious excitation-dependent property with the quantum yield of 1.8%. In addition, expired passion fruit pulp was treated using hydrothermal method. The final product was analyzed using TEM and GC–MS. The result shows the high content of furandione in the product, which indicates the potential for further extraction by purification. This paper expands new way for the reuse of expired fruits.

Magnetoresistance effects are used in a variety of devices including hard disk drives and magnetic random access memories. In particular, giant magnetoresistance and tunnelling magnetoresistance can be used to create spin valves and tunnel junctions in which the resistance depends on the relative magnetization orientations of two ferromagnetic conducting layers. Here, we report a magnetoresistance effect that occurs in a platinum layer deposited on a magnon junction consisting of two insulating magnetic yttrium iron garnet (YIG) layers separated by an antiferromagnetic nickel oxide spacer layer. The resistance of the platinum layer is found to depend on the magnetization of the YIG layer in direct contact with it (an effect known as spin Hall magnetoresistance), but also the magnetization of the adjacent YIG layer in the junction. The resistance of the platinum layer is higher when the two YIG layers are aligned antiparallel than when parallel. We assign this behaviour to a magnonic nonlocal spin Hall magnetoresistance in which spin-carrying magnon propagation across the junction affects spin accumulation at the metal interface and hence modulates the spin Hall magnetoresistance. The effect could be used to develop spintronic and magnonic devices that have spin transport properties controlled by an all-insulating magnon junction and are thus free from Joule heating. A magnetoresistance effect that occurs in a platinum layer deposited on a magnon junction consisting of two insulating magnetic yttrium iron garnet layers separated by an antiferromagnetic nickel oxide spacer layer could be used to create spintronic and magnonic devices that are free from Joule heating.

China discovered Fuling shale gas field in 2012. The production dropped dramatically for early drilled wells with the time. Refracturing the wells to maintain production is a must to keep the field economically viable. A new method of cementing a smaller inner casing inside legacy production casing and then plug-and-perf fracturing was executed and the production was rejuvenated. The procedure consists of well kill, wellbore cleanout and reaming, cure losses and then cementing. The wellbore re-construction process will isolate all existing perforations in the wellbore, and it can pass the pressure test for fracturing. The legacy wellbore is 5.5 inch size and a specialized 3.5 inch semi-flush joint casing was selected as new production string. A dependable cement barrier in this extremely tight annulus is required to carry on future re-fracturing operation. 2D hydraulic simulations and computational fluid dynamic was performed to optimize slurry density, rheology, and the method of cement placement. The cement mechanical property is enhanced to withstand the high pressure of fracturing. The top of cement in the annulus will be above the topmost existing perforation. The remaining 3.5 inch casing above the designed depth was disconnected and pulled out. The wellbore was cleaned, and the losses were treated prior cementing. Tailored ceramic centralizers were installed on the casing surface to achieve optimum stand-off. The centralizer's friction factor is low to casing running to bottom successfully. A low rheology slurry tailored for optimum mechanical properties of fracturing operation was pumped, and the cement returns to designed depth were noted. The casing string disconnected at designed depth and pulled out successfully. After waiting on cement, the wellbore passed pressure test. Cement bond log showed excellent results and the top of cement reached the designed depth. The stage fracturing operation was performed with no issues of wellbore integrity. A typical procedure of casing-in-casing cementing were recognized. Tailored slurry and centralizers design helped to achieve zonal isolation objective in the low clearance Casing-in-Casing cementing. The critical wellbore re-construction objective achieved and well was re-fractured with substantial increase in production.

Fuling shale gas field is one of the most successful shale gas play in China. Production logging is one of the vital technologies to evaluate the shale gas contribution in different stages and different clusters. Production logging has been conducted in over 40 wells and most of the operations are successful and good results have been observed. Some previous studies have unveiled one or several wells production logging results in Fuling shale gas play. But production logging results show huge difference between different wells. In order to get better understanding of the results, a comprehensive overview is carried out. The effect of lithology layers, TOC (total organic content), porosity, brittle mineral content, well trajectory is analyzed. Results show that the production logging result is consistent with the geology understanding, and fractures in the favorable layers make more gas contribution. Rate contribution shows positive correlation with TOC, the higher the TOC, the greater the rate contribution per stage. For wells with higher TOC, the rate contribution difference per stage is relatively smaller, but for wells with lower TOC, it shows huge rate contribution variation, fracture stages with TOC lower than 2% contribute very little, and there exist one or several dominant fractures which contributes most gas rate. Porosity and brittle minerals also show positive effect on rate contribution. The gas rate contribution per fracture stage increases with the increase of porosity and brittle minerals. The gas contribution of the front half lateral and that of latter half lateral are relatively close for the "upward" or horizontal wells. However, for the "downward" wells, the latter half lateral contribute much more gas than the front half lateral. It is believed that the liquid loading in the toe parts reduced the gas contribution in the front half lateral. The overview research is important to get a compressive understanding of production logging and different fractures’ contribution in shale gas production. It is also useful to guide the design of horizontal laterals and fractures scenarios design.

With active hydraulic fracturing performed since 2012, the Fuling shale gas field in China is one of the largest shale gas fields outside of North America. Recently, a Casing-in-Casing (CiC) refracturing treatment was successfully implemented, resulting in production beyond expectations. This was the first successful application of a CiC refracturing treatment in a horizontal shale gas well in this region, thus providing a new option for refracturing horizontal wells in China. Bullheading diversion refracturing with diverting balls was previously attempted in this field with high initial production observed; however, production was inconsistent and quickly declined. Therefore, the operator decided to attempt a CiC refracturing method in an understimulated candidate well. This involved installing and cementing 3.5-in. casing in 5.5-in. casing to effectively isolate the perforations, which enabled plugging and perforating operations in the reconstructed wellbore for an effective refracturing treatment. A customized refracturing design integrated the production profile, residual recoverable reserves, and the specific 5.5- × 3.5-in. reconstructed wellbore limitation. The length of the 3.5-in. casing was optimized to be as short as possible but still cover the original perforations, and high-performance slickwater was used to reduce pipe friction, thus increasing the treatment rate. An engineered breakdown approach was employed for improved fracture initiation. Additionally, more clusters were added between the original clusters and, based on production profile results, some of the original understimulated clusters with little proppant placement were reperforated. To overcome the impact of depleted fractures, a self-degradable particulate diverting agent was used to propagate new fractures, allowing access to new rock to increase total reserve recovery. The treatment in the reconstructed wellbore was successful, with 21 stages fractured in 12 days, achieving 100% placement of the designed proppant and fluid. A treatment rate of 7 to 12 m3/min from the toe to heel was executed as designed. Test production of 183,800 m3/D was also achieved with a recovery rate of 88.1%. Production has remained consistent and wellhead pressure has remained steady at a high level throughout the first two months of production. CiC refracturing technology helps overcome common disadvantages experienced with traditional refracturing techniques, such as poorly placed proppant and fluid and inconsistent production. CiC refracturing not only allows exploitation of bypassed reserves from original fractures, but also allows precise stimulation of new rock to obtain the highest reserve recovery. The successful implementation of this case study illustrates the reliability of CiC refracturing technology and provides valuable experience to be used during future regional horizontal well refracturing.

In this study, a coaxial electrospray process was used to produce nanoparticles, in which thymol was encapsulated in a core–shell of zein and shellac. We then investigated fluid velocity and solution concentrations on the electrospray. Scanning electron microscopy revealed that the thymol/zein/shellac particles prepared at a flow rate ratio of 0.6:0.3 mL/h were rounder with smaller diameters. The highest encapsulation efficiency of thymol was 81.34%, the average particle size was 606.53 nm, and the retention rate of thymol was 68.74% after 30 days. Moreover, we investigated the thermal stability, antimicrobial activity, and simulated gastrointestinal release curves of the nanoparticles. Finally, the nanoparticles were used as a coating for fresh-cut cantaloupe. Compared with the blank nanoparticle control group, the coating significantly extended the shelf life of cantaloupe to 16 days. Our results indicate that these nanoparticles have great potential for application in food preservation.

In this study, poly (e-caprolactone) (PCL)/zein/Ag nanoparticle (AgNP) fibrous membranes were prepared by ultrasonication-assisted electrospinning. The effects of the AgNP content and ultrasonication time on the membrane morphology, chemical structure, biodegradability, mechanical properties, antibacterial/antiviral activity, and air filtration performance were studied. The best-performing membrane (AgNP content = 1% (w/v), sonication time = 30 min) exhibited a bead-on-string morphology, an air permeability of 93.6 ± 1.5 mm s−1, and the Escherichia coli and Staphylococcus aureus removal efficiencies of 98.1 ± 1.2% and 97.4 ± 2.5%, respectively. In an experiment with E. coli phage, the above-mentioned membrane exhibited a 97.1 ± 2.1% virus removal efficiency after 60 min. The high performance of this bead-on-string membrane for air filtration was ascribed to the low packing density due to the presence of open interconnected beaded airflow channels and small beads.