Strength, deformability and failure behaviors of rock masses are significantly affected by the widespread natural fissures that are often distributed in overlapped patterns. To investigate the ...failure mechanism of rock masses with overlapped fissures, uniaxial compressive tests and numerical studies were conducted on Portland cement samples containing folded flaws of different dip angles and undulation angles. The folded flaw was overlapped by several fractures at the ends. Crack initiation, propagation and coalescence were systematically investigated. Results show that there are two patterns in terms of the deformational curves of specimens containing folded flaws, i.e., the bimodal type and the single peak type. Five different failure modes were observed, including compaction, dilation, shear off crush and slip. In all specimens crack coalescence is caused by the linkage of shear cracks with the folded flaw although the failure surfaces are different because of the different failure modes of the folded flaw. After coalescence, the folded flaw can still resist a certain level of shear stress, indicating that it has shear strength, which contributes to the residual peak strength showing in the stress-displacement curves. It is also found that the failure characteristics of specimens containing folded flaws integrate the failure characteristics of rock joint under compressive shear and smooth fracture under compression, which is significantly correlated with the undulation and dip angles of the folded flaw. The findings can provide a better understanding of the failure mechanism of rock masses with folded fractures.
•Established a folded flaw to investigate the failure mechanism of overlapped fissures.•Numerically revealed the crack mechanism of material containing folded flaw.•Undulation angle and dip angle play key roles in the failure process of folded flaw.•Failure mode integrates characteristics of joint under compressive shear and smooth fracture under compression.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
To date, various hydrogels have been manufactured for wearable sensors, but the simultaneous realization of optical transparency, remarkable mechanical properties, excellent sensing properties and ...anti-freezing features by using cheap raw materials and an easy synthesis process remains challenging. Here, high performance PVA/glycerol/NaCl (PGN) ionic hydrogel sensors were facilely manufactured to overcome these challenges. The proposed hydrogel sensors were fabricated by physically mixing the biocompatible poly(vinyl alcohol) and nontoxic glycerol in water as the gel matrix followed by soaking in saturated NaCl aqueous solution. The resulting PVA/glycerol/NaCl hydrogels exhibited good transparency (>88%), favorable stretchability (570.7%), outstanding mechanical strength (3.1 MPa), and high toughness (8.65 MJ m
−3
). Meanwhile, the PGN ionic hydrogel sensors displayed excellent stretching sensitivity with a gauge factor of 4.01, and it could repeatedly and stably detect accurate electrical signals under both large strains and subtle strains. Furthermore, our hydrogel sensors were endowed with anti-freezing features on account of the presence of both glycerol and NaCl, and the sensors could still maintain good mechanical and strain-sensitive performance at a low temperature (−20 °C). Based on the above characteristics, the biocompatible PGN hydrogel sensors could be employed as wearable devices to detect various human motions (
e.g.
finger, wrist, elbow, and knee joints) at room temperature and low temperature. Therefore, the as-prepared hydrogels show promising potential as high-performance wearable strain sensors for practical applications in biomimetic prostheses and human activity monitoring systems.
Transparent, high-strength, stretchable, sensitive and anti-freezing poly(vinyl alcohol) ionic hydrogel sensors were facilely fabricated for human motion monitoring.
Trifluoromethylated acetylenes and arenes are widely applicable in the synthesis of pharmaceuticals and agrochemicals. In 2010, our group has reported the copper-mediated oxidative trifluomethylation ...of terminal alkynes and aryl boronic acids. This method allows a wide range of functional group tolerant trifluoromethylated acetylenes and arenes to be easily prepared. After the preliminary mechanistic studies of the oxidative trifluoromethylation of terminal alkyne, an efficient copper-catalyzed oxidative trifluoromethylation of terminal alkynes and aryl boronic acids has been developed. The catalytic protocol is successfully achieved by adding both the substrate and a portion of CF3TMS slowly using a syringe pump to the reaction mixture.
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IJS, KILJ, NUK, PNG, UL, UM
A practical and efficient synthesis of C(3)-trifluoromethanesulfanylated hexahydropyrrolo2,3-bindoles 5 from tryptamine derivatives was described. The features of this synthesis included ...electrophilic activation of C(3) of tryptamine derivatives with “CF3S+” and cascade ring cyclization by carbamate nucleophile attacking at C(2). Surprisingly, when Lewis acid (BF3·OEt2) was used as activator instead of proton acid (TsOH·H2O) for the electrophilic trifluoromethanesulfanylation of tryptamine derivatives, the uncyclized product 6 was formed preferentially. This sequential trifluoromethanesulfanylation–cyclization protocol was used to synthesize several pyrrolidinoindolinic alkaloid analogues. The cytotoxicity activities of these trifluoromethanesulfanylated alkaloid analogues were evaluated against three cancer cell lines (K562, HeLa, L929).
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IJS, KILJ, NUK, PNG, UL, UM
Graphene based aerogel has become one of the most likely functional adsorption materials that is applicable to purify various contaminated water sources, such as dye wastewater, because of its high ...porosity, structural stability, large specific surface area, and high adsorption capacity. In this study, chitosan and graphene oxide were first selected as the matrix to prepare the composite hydrogel through the hydrothermal method, which was further frozen and dried to obtain the target aerogel. The microscopic structures and adsorption capacity of the composite aerogel were then characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and N2 (nitrogen) physical adsorption and desorption tests. The results show that the specific surface area of the composite aerogel was reached at 297.431 m2/g, which is higher than that of graphene oxide aerogel and chitosan aerogel. The aperture was reduced to about 3 nm. The adsorption rate of the composite aerogel for the methyl orange solution was as high as 97.2% at pH = 1, and the adsorption capacity was 48.6 mg/g. The adsorption process of the composite aerogel satisfies the Langmuir equation and can be described by the second-order adsorption kinetics. In addition, it is worth noting that this composite aerogel can provide a striking adsorption characteristic on methyl orange due to the combining effects from massive amino groups on chitosan and the structural conjugation of graphene oxide.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Background:
Intervertebral disc degeneration (IDD) is a major cause of low back pain, but the onset and progression of IDD are unknown. Long non-coding RNA (lncRNA) has been validated to play a ...critical role in IDD, while an increasing number of studies have linked oxidative stress (OS) to the initiation and progression of IDD. We aim to investigate key lncRNAs in IDD through a comprehensive network of competing endogenous RNA (ceRNA) and to identify possible underlying mechanisms.
Methods:
We downloaded IDD-related gene expression data from the Gene Expression Omnibus (GEO) database and obtained differentially expressed-lncRNAs (DE-lncRNA), -microRNAs (DE-miRNA), and -messenger RNAs (DE-mRNA) by bioinformatics analysis. The OS-related lncRNA-miRNA-mRNA ceRNA interaction axis was constructed and key lncRNAs were identified based on ceRNA theory. We performed gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses on mRNAs regulated by lncRNAs in the ceRNA network. Single sample gene set enrichment analysis (ssGSEA) was used to reveal the immune landscape. Expression of key lncRNAs in IDD was assessed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).
Results:
In this study, 111 DE-mRNAs, 20 DE-lncRNAs, and 502 DE-miRNAs were identified between IDD patients and controls, and 16 OS-related DE-lncRNAs were also identified. The resulting lncRNA-miRNA-mRNA network consisted of eight OS-related DE-lncRNA nodes, 24 DE-miRNA nodes, 70 DE-mRNA nodes, and 183 edges. Functional enrichment analysis suggested that the ceRNA network may be involved in regulating biological processes related to cytokine secretion, lipid, and angiogenesis. We also identified four key lncRNAs, namely lncRNA GNAS-AS1, lncRNA MIR100HG, lncRNA LINC01359, and lncRNA LUCAT1, which were also found to be significantly associated with immune cells.
Conclusion:
These results provide novel insights into the potential applications of OS-related lncRNAs in patients with IDD.
MXenes, or transition metal carbides or nitrides, as an advanced 2D materials have already attracted extensive attention due to their high conductivity and large specific surface area for ...applications in the field of energy storage. MXenes also have many other advanced properties such as good transmittance and adjustable work function over a large range. However, few works study the properties of MXenes in the field of optoelectronics. Here, the optoelectronic properties of Ti3C2TX (with a work function of 4.37 eV) on n‐type silicon (n‐Si) of vertical van der Waals heterostructures are studied. The Ti3C2TX not only functions as the transparent electrode but also contributes to the separation and transport of photo‐induced carriers. After investigations on the influence of annealing, temperature, illumination, and applied voltage on the performance of Ti3C2TX/n‐Si Schottky junction heterostructures, this study fabricates a self‐driven vertical junction photodetectors with high response and recovery speeds. It is believed that the excellent photoelectric properties of MXenes will attract many researchers' attention to the application of MXenes in the photoelectrical field.
Ti3C2TX/n‐Si van der Waals heterostructures are fabricated by dropping Ti3C2TX colloidal solution on n‐Si substrate. The Ti3C2TX film not only functions as the transparent electrode but also contributes to the separation and transport of photo‐induced carriers. On/off ratio and responsivity of the optimized Ti3C2TX/n‐Si device can reach to ≈105 and 26.95 mA W−1, respectively.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
To better understand the efficacy and safety of Bifidobacterium quadruple viable tablets in the treatment of helicobacter pylori (H. pylori)-infected peptic ulcer or gastritis patients.
A systematic ...review of the studies published to June 2022 was performed in English database PubMed, Embase, Chinese database CNKI, Wanfang. There were 17 studies were included in this systematic review and meta-analysis. The outcomes measured included H. pylori eradication rate, changes in clinical symptoms of epigastric pain scores, and the incidence of adverse reactions.
The results of the fixed effect model showed that the eradication rate of H. pylori in the combination of Bifidobacterium quadruple viable bacteria tablets combined with bismuth-containing conventional quadruple therapy was greater than that of bismuth-containing conventional quadruple therapy, and the difference was statistically significant (OR = 3.73, 95%CI (2.79,5.00), Z = 2.78, P < 0.001; I
= 0.0%, P > 0.999). The results of random effects model showed that the epigastric pain score of Bifidobacterium quadruple viable bacteria tablets combined with bismuth-containing conventional quadruple therapy was lower than that of bismuth-containing conventional quadruple therapy, and the difference was statistically significant (WMD=-0.70, 95%CI (-1.06,-0.34), Z = 3.82, P < 0.001; I
= 96.7%, P < 0.001). The results of random effects model showed that the acid reflux score of Bifidobacterium quadruple viable bacteria tablets combined with bismuth-containing conventional quadruple therapy was lower than that of bismuth-containing conventional quadruple therapy, and the difference was statistically significant (WMD=-0.98, 95%CI (-1.70,-0.26), Z = 2.66, P < 0.001; I
= 99.7%, P < 0.001).
The eradication rate of H. pylori by Bifidobacterium quadruple viable bacteria tablets combined with bismuth-containing quadruple therapy is better than that of bismuth-containing quadruple therapy. The improvement of clinical symptoms of patients is better than that of bismuth-containing quadruple therapy, and the incidence of adverse reactions is lower than that of bismuth-containing quadruple therapy. Bifidobacterium quadruple viable bacteria tablet combined with bismuth-containing quadruple therapy was effective and safe. It provides a new way to treat patients with H. pylori.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Large-scale production of green and pollution-free materials is crucial for deploying sustainable clean energy. Currently, the fabrication of traditional energy materials involves complex ...technological conditions and high costs, which significantly limits their broad application in the industry. Microorganisms involved in energy production have the advantages of inexpensive production and safe process and can minimize the problem of chemical reagents in environmental pollution. This paper reviews the mechanisms of electron transport, redox, metabolism, structure, and composition of electroactive microorganisms in synthesizing energy materials. It then discusses and summarizes the applications of microbial energy materials in electrocatalytic systems, sensors, and power generation devices. Lastly, the research progress and existing challenges for electroactive microorganisms in the energy and environment sectors described herein provide a theoretical basis for exploring the future application of electroactive microorganisms in energy materials.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A physical shaking table test model of the shallow-bias tunnel with a small clear distance whose scale was 1:10 was performed to study the type, direction and acceleration peak of the seismic wave ...which have an immense influence on the dynamic response characteristics of the tunnel. In shaking table model test, the Wen Chuan wave (wc–xz), Da Rui wave (dr–xz) and Kobe wave (k–xz) were adopted as loading wave in x, z-direction (horizontal and vertical direction loading at the same time). The results show that under the action of seismic wave, the acceleration amplification factor of z-direction is generally larger than that of x-direction. Compared with the lining of the right hole, the acceleration amplification factor and variation trend of the lining of the left hole are highly different. The strain is less affected by the type of seismic wave, but that is greatly affected by acceleration peak. The tension strain increases with the increase of the acceleration peak of seismic wave, and is larger than the compression strain at each measuring point. The variation trend of tension strain is more intense than the compression strain.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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