Low-viscosity slickwater fracturing fluids are a crucial technology for the commercial development of shallow shale gas. However, in deep shale gas formations with high pressure, a higher sand ...concentration is required to support fractures. Linear gel fracturing fluids and crosslinked gel fracturing fluids have a strong sand-carrying capacity, but the drag reduction effect is poor, and it needs to be pre-prepared to decrease the fracturing cost. Slick water fracturing fluids have a strong drag reduction effect and low cost, but their sand-carrying capacity is poor and the fracturing fluid sand ratio is low. The research and development of viscous slick water fracturing fluids solves this problem. It can be switched on-line between a low-viscosity slick water fracturing fluid and high-viscosity weak gel fracturing fluid, which significantly reduces the cost of single-well fracturing. A polyacrylamide drag reducer is the core additive of slick water fracturing fluids. By adjusting its concentration, the control of the on-line viscosity of fracturing fluid can be realized, that is, 'low viscosity for drag reduction, high viscosity for sand-carrying'. Therefore, this article introduces the research and application status of a linear gel fracturing fluid, crosslinked gel fracturing fluid, and slick water fracturing fluid for deep shale gas reservoirs, and focuses on the research status of a viscous slick water fracturing fluid and viscosity-controllable polyacrylamide drag reducer, with the aim of providing valuable insights for the research on water-based fracturing fluids in the stimulation of deep shale gas reservoirs.
Highly stretchable and conductive ionogels have great potential in flexible electronics and soft robotic skins. However, current ionogels are still far from being able to accurately duplicate the ...mechanically responsive behavior of real human skin. Furthermore, durable robotic skins that are applicable under harsh conditions are still lacking. Herein, a strong noncovalent interaction, ionic clusters, is combined with hydrogen bonds to obtain a physically cross-linked ionogel (PCI). Benefiting from the strong ionic bonding of the ionic cluster, the PCI shows strain-stiffening behavior similar to that of human skin, thus enabling it to have a perception-strengthening ability. Additionally, the strong ionic clusters can also ensure the PCI remains stable at high temperatures. Even when the temperature is raised to 200 °C, the PCI can maintain the gel state. Moreover, the PCI exhibits high transparency, recyclability, good adhesion, and high conductivity. Such excellent features distinguish the PCI from ordinary ionogels, providing a new way to realize skin-like sensing in harsh environments for future bionic machines.
By connecting a fluorinated molecule 2,5-bis((4-(perfluorohexyl)benzoyl)oxy)benzoic acid (6DFP) to the poly(4-vinylpyridine) (P4VP) backbone through hydrogen bonding, we synthesized a new series of ...fluorinated supramolecular mesogen-jacketed liquid crystalline polymer (MJLCP) P4VP(6DFP)x, where x is the molar ratio of donor to acceptor. Polarized light microscopy and wide-angle X-ray scattering were used to investigate the liquid crystallinity of the resulting complexes. The results show that this kind of supramolecular MJLCP has good thermal stability, with the isotropization temperature of about 170 °C. Subsequently, by connecting the fluorinated molecule 6DFP to the commercially available coil−coil block copolymer (BCP) polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) chain also via hydrogen bond, we constructed a series of supramolecular rod−coil BCP PSmVn(6DFP)x, where m and n are the degrees of polymerization of PS and P4VP, respectively. PSmVn(6DFP)x exhibits a hierarchically ordered self-assembled structure. Owing to the introduction of fluorine atoms, the Flory-Huggins interaction parameter (χ) of such a supramolecular BCP is high. BCP sample with a low total degree of polymerization can still be ordered, and the periodic size can be as low as 11.5 nm. This work provides a new approach for the construction of small-sized structures by supramolecular BCPs via hydrogen bonding, which can be used as nanotemplates and nanoporous materials after selective removal of the small molecules.
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•Fluorinated supramolecular MJLCP with high stability obtained by hydrogen bonding from a fluorinated small molecule and P4VP.•Fluorinated supramolecular high-χ rod−coil BCP with the above rod-like MJLCP constructed from PS-b-P4VP by hydrogen bonding.•Self-assembled structure of the supramolecular BCP regulated, with a minimum periodic size of 11.5 nm.
Construction of sub‐5 nm long‐range ordered structures through self‐assembly has received increasing attention. Herein, a series of ODMS‐based thermotropic liquid crystals (LCs) containing perylene ...diimide (PDI) were designed and synthesized. These LCs can form ordered nanostructures with periodic sizes around 5 nm including smectic J (SmJ), oblique columnar (Colob), and hexagonal columnar (Colh) phases with change in the volume fraction of ODMS, where the layer spacing of the SmJ phase is less than 5 nm. Thin films with parallel oriented nanolines with line width less than 5 nm can be obtained on PDMS‐modified silicon substrates by spin‐casting and simple thermal annealing processes. Moreover, owing to the strong π‐π interaction between PDI cores, these nanolines are long‐range ordered with uniaxial orientation in relatively large areas (1.5×1.5 μm2) with over 300 continuous microdomains without pre‐patterning. These nanostructures provide the possibility of preparing nanotemplates by oxygen plasma etching.
Perylene diimide‐based disc‐coil liquid crystals containing oligo(dimethylsiloxane) chains can form lamellar and columnar phases, and large‐area uniaxially orientated nanolines can be obtained through thin‐film self‐assembly.
The type of self-assembled structure has a significant impact on the ionic conductivity of block copolymer or liquid crystalline (LC) ion conductors. In this study, we focus on the effect of ...self-assembled structures on the ionic conductivity of a non-block copolymer, LC ion conductor, which is a mixture of an azobenzene monomer (NbAzo), pentaerythritol tetre(3-mercapropionate) (PETMP), and a lithium salt, lithium bis(trifluoromethane)sulfonimide (LiTFSI). The self-assembled structures and ionic conductivities of ion conductors having different doping ratios of lithium salt to monomer were examined. With the increase in the doping ratio, the self-assembled structure transforms from lamellae (LAM) to double gyroid (GYR). The effect of self-assembled structure on ionic conductivity was analyzed; it was found that the conductivity of the GYR structure was about 3.6 times that of the LAM one, indicating that obtaining the GYR structure is more effective in improving ionic conductivity.
The self-assembled structure plays an important role in the ionic conductivity of a non-block copolymer, LC ion conductor.
Screening plants that are hypertolerant to and excluders of certain heavy metals plays a fundamental role in a remediation strategy for metalliferous mine tailings. A field survey of terrestrial ...higher plants growing on Mn mine tailings at Huayuan, Hunan Province, China was conducted to identify candidate species for application in phytostabilization of the tailings in this region. In total, 51 species belonging to 21 families were recorded and the 12 dominant plants were investigated for their potential in phytostabilization of heavy metals. Eight plant species, Alternanthera philoxeroides, Artemisia princeps, Bidens frondosa, Bidens pilosa, Cynodon dactylon, Digitaria sanguinalis, Erigeron canadensis, and Setaria plicata accumulated much lower concentrations of heavy metals in shoots and roots than the associated soils and bioconcen- tration factors （BFs） for Cd, Mn, Pb and Zn were all 〈 1, demonstrating a high tolerance to heavy metals and poor metals translocation ability. The field investigation also found that these species grew fast, accumulated biomass rapidly and developed a vegetation cover in a relatively short time. Therefore, they are good candidates for phytostabilization purposes and could be used as pioneer species in phytoremediation of Mn mine tailings in this region of South China.
Wearing gloves during machinery operation in workshops is essential for preventing accidental injuries, such as mechanical damage and burns. Ensuring that workers are wearing gloves is a key strategy ...for accident prevention. Consequently, this study proposes a glove detection algorithm called YOLOv8-AFPN-M-C2f based on YOLOv8, offering swifter detection speeds, lower computational demands, and enhanced accuracy for workshop scenarios. This research innovates by substituting the head of YOLOv8 with the AFPN-M-C2f network, amplifying the pathways for feature vector propagation, and mitigating semantic discrepancies between non-adjacent feature layers. Additionally, the introduction of a superficial feature layer enriches surface feature information, augmenting the model's sensitivity to smaller objects. To assess the performance of the YOLOv8-AFPN-M-C2f model, this study conducted multiple experiments using a factory glove detection dataset compiled for this study. The results indicate that the enhanced YOLOv8 model surpasses other network models. Compared to the baseline YOLOv8 model, the refined version shows a 2.6% increase in mAP@50%, a 63.8% rise in FPS, and a 13% reduction in the number of parameters. This research contributes an effective solution for the detection of glove adherence.
•Lakes in the endorheic basin exhibited a rapid expansion since 2000.•The significant lake expansion was observed in the Hoh Xil region.•Lake expansion was closely related to precipitation and ...permafrost degradation.•Meltwater from permafrost thawing contributes to 21% of lake volume change.•Glacier retreat contributed to expansion of several large lakes.
The QTP (Qinghai-Tibet Plateau) holds the greatest concentration of high-elevation inland lakes in the world, and most of these lakes are located in the QTP endorheic basin. Accelerated lake expansion in the endorheic basin since 2000 has been confirmed by many studies, but there is disagreement as to which components of the water balance explain most of the lake expansion. In this paper, based on Landsat images, meteorological data, glacier data and permafrost monitoring data, we analyzed the spatial–temporal changes in lake area and further explored the driving factors behind rapid lake expansion in different zones in the endorheic basin. The results suggested that the spatial pattern of trends in lake area in the endorheic basin from 2000 to 2017 showed a southwest-northeast transition from contracting to slightly expanding to rapidly expanding. More importantly, the dramatic lake expansion observed in most regions was statistically significant (0.01 ~ 26.29 km2/yr). Although retreating glaciers may have contributed to lake growth, this can not fully explain the recent lake expansion. We find that increasing precipitation was the primary driver behind lake expansion, and that permafrost degradation accelerated lake expansion. Lakes on the northern slope of the Gangdise Mountains, fed by the most rapidly retreating glaciers, were relatively stable or even contracted. In contrast, most of the non-glacier-fed lakes in the Hoh Xil region and the central endorheic basin nevertheless experienced significant expansion and slight expansion, respectively, which were mainly attributed to the greatest increase in AP (annual precipitation). Remarkable lake expansion was found in the continuous permafrost zone. The increasing ALT (active layer thickness) and soil temperature of permafrost resulted in an increase in meltwater from ground ice, the partial release of soil moisture and an amount of unfrozen water content, which has contributed to supply lakes and accelerated lake expansion.
Inhibiting proliferation and inducing apoptosis of myofibroblasts is becoming one of the promising and effective ways to treat hypertrophic scar. ABT-263, as an orally bioavailable BCL-2 family ...inhibitor, has showed great antitumor characteristics by targeting tumor cell apoptosis. The objective of this study was to explore whether ABT-263 could target apoptosis of overactivated myofibroblasts in hypertrophic scar.
, we used ABT-263 to treat scars in a rabbit ear scar model. Photographs and ultrasound examination were taken weekly, and scars were harvested on day 42 for further Masson trichrome staining.
, the expression levels of BCL-2 family members, including prosurvival proteins, activators, and effectors, were detected systematically in hypertrophic scar tissues and adjacent normal skin tissues, as well as in human hypertrophic scar fibroblasts (HSFs) and human normal dermal fibroblasts (HFBs). The roles of ABT-263 in apoptosis and proliferation of HSFs and HFBs were determined by annexin V/PI assay, CCK-8 kit, and cell cycle analysis. Mitochondrial membrane potential was evaluated by JC-1 staining and the expression of type I/III collagen and α-SMA was measured by PCR, western blotting, and immunofluorescence staining. Furthermore, immunoprecipitation was performed to explore the potential mechanism.
, ABT-263 could significantly improve the scar appearance and collagen arrangement, decrease scar elevation index (SEI), and induce cell apoptosis.
, the expression levels of BCL-2, BCL-XL, and BIM were significantly higher in scar tissues and HSFs than those in normal skin tissues and HFBs. ABT-263 selectively induced HSFs apoptosis by releasing BIM from binding with prosurvival proteins. Moreover, ABT-263 inhibited HSFs proliferation and reduced the expression of α-SMA and type I/III collagen in a concentration- and time- dependent manner.
HSFs showed increased mitochondrial priming with higher level of proapoptotic activator BIM and were primed to death. ABT-263 showed great therapeutic ability in the treatment of hypertrophic scar by targeting HSFs.
Copper (Cu) compounds are a promising candidate for next generation metal anticancer drugs and have been extensively studied. Therefore, four binuclear copper(II) compounds derived from Schiff base ...thiosemicarbazones (L1–L4), namely CuCl(L1)2 (C1), CuNO3(L2)2 (C2), Cu(NCS) (L3)2 (C3) and Cu(CH3COO) (L4)2 (C4) were synthesized and characterized. Four of these compounds showed very high cytotoxicity to cancer cell lines in vitro. These Cu(II) compounds strongly promoted the apoptosis of BEL-7404 cells. The formation of reactive oxygen species (ROS), change in mitochondrial membrane potential and western blot analysis revealed that Cu compounds could induce cancer cell apoptosis through the intrinsic ROS-mediated mitochondrial pathway accompanied by the regulation of Bcl-2 family proteins.
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•Four binuclear Cu(II)-Schiff base complexes were synthesized and characterized.•Cu complexes have high anticancer activity.•Cu complexes induce cells apoptosis possible via intrinsic ROS-mediated mitochondrial pathway.•Cu complexes regulate Bcl-2 family proteins.
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