Cutouts are commonly found in aerospace, ships, and marine structures, which have a great influence on mechanical properties such as stress concentration, natural frequency, and structural ...load-bearing performance of the structure. In this study, buckling behaviors of a square plate with a circular flanged cutout at the center are explored numerically, aiming to address the influence of different cutout parameters on the elastic and elasto-plastic buckling behaviors of the perforated plate. The flanged-perforated plate is subjected to uniaxial compressive loads, and the four edges are simply supported in the out-of-plane direction. The influence of various cutout parameters on the elastic and elasto-plastic buckling behaviors of the perforated plate is examined through a series of buckling analysis. In addition, structural weight reduction of the uniaxial compressed perforated square plates is carried out under the constraint of the elastic buckling stress of the plate structure. The findings indicate that different cutout parameters have a significant impact on the buckling performance of the plate. Perforated plates with flanging exhibit higher buckling strength than those without flanging, and variations in plate geometric parameters (such as the plate slenderness ratio and cutout radius ratio) are associated with increases in elastic buckling stress and elasto-plastic ultimate strength. The results of this paper can provide references for the design of flanged-cutouts in engineering.
As a screw dislocation approaches an intrinsic stacking fault (SF) from one side, the SF may be: (1) annihilated; or (2) transformed into an extrinsic stacking fault; or (3) penetrated. Meanwhile, as ...a screw dislocation interacts with an extrinsic stacking fault (ESF), the ESF may be: (1) transformed into a three-layer thick twin; or (2) transformed into an SF; or (3) penetrated. Display omitted
► We study the impingement of screw dislocation on intrinsic/extrinsic stacking fault. ► Six interaction modes have been identified. ► We analyze the resistance to, and establish the criterion for, each mode. ► We reveal the critical shear stresses for the transition among different modes.
The mechanical properties of polycrystalline metals greatly depend on the interaction between lattice dislocation and planar defects, but some details about this interaction still need to be explored. In this paper, we investigated the impingement of a screw dislocation on intrinsic stacking fault (SF) and extrinsic stacking faults (ESF) in different FCC metals by using the molecular dynamics simulations. As a screw dislocation approaches a SF from one side, the response of SF will be one of the results: (1) annihilated; (2) transformed into ESF; (3) penetrated. Also, as a screw dislocation interacts with ESF, the response of ESF will be one of the results: (1) transformed into a three-layer thick twin; (2) into an SF; (3) penetrated. Dimensionless parameters relevant to the planar fault energies and their ratios are used to predict the propensity to different interaction modes. The results reveal the evolution law of internal defects clearly, which will be significant to further understand the details of plastic deformation and to seek the underlying techniques for strengthening metals.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The composite hydrogel performs integrated PTT for osteogenesis and bacterial eradication. With NIR stimulation, precisely controlled-release of BMP-2 and tannin by the hydrophobic phenomenon of ...volume contraction along with local heating helps the osteogenic differentiation of BMSCs, and slow release of natural component O-HACC in combination with hyperthermia exhibits excellent antibacterial efficiency by relative low temperature to avoid potential unexpected damage.
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•A NIR-responsive and multi-functional hydrogel system packaged with bioactive factors was fabricated.•Programmable NIR irradiation performed anti-microbial, anti-oxidative and pro-osteogenic functions respectively.•Administration of controllable photothermal strategy achieved a synergistic therapeutic effect on bone regeneration.
Progress toward developing next-generation biomaterials applied in complex bone defect is expected to effectively integrate osteogenic and anti-bacteria capability. However, current biomaterials often achieve the two functions separately. Inspired by photothermal effect, exogenous light-induced thermal variations can efficiently facilitate bone regeneration and bacteria eradication. Here, a bioactive hydrogel BMP-2@PNH-TA with simultaneously osteogenic and anti-bacterial capacities is presented, which is based on the near infrared (NIR) induced photothermal effect to perform integrated photothermal therapy (PTT). In detail, photothermal effect and photothermal-controlled release of osteogenic and anti-bacterial factors through sponge-like effect could exert integrated influence on bone regeneration under complex situation. The composite hydrogel can mediate pro-osteogenesis under mild temperature and controlled release of BMP-2 and tannin in response to NIR stimulation with low power, while efficiently eradicate bacteria via controlled release of O-HACC and thermal effect with high power. The customized PTT strategy significantly shortened the duration time of bone regeneration up to almost 50% in rat cranial bone defect. It is anticipated that the concept of integrated PTT for bone regeneration will cast new insights into developing high-performance therapeutic strategy with combined biological functions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this letter, we propose a new method based on the optical sectioning microscopy to characterize the multilayer structure with micro-scale air gaps. With this technique, sinusoidal fringe patterns ...having a predefined shifted phase produced by digital micro-mirror devices are illuminated onto the sample. The contrast response curve (CRC) of the reflected patterns along the scanning direction is determined by the phase-shifting algorithm, while the object is scanned through the focus of the microscope. The maximum contrast value of the CRC occurs at the position where the sample is on the focal plane. The peak positions of the CRC are extracted through the Gaussian fitting and then implemented to achieve the surface topography and gap thickness distribution. To suppress the noise influence caused by the environment fluctuations or other factors, the frequency-domain analysis has been introduced in this letter. The simulations and experiments are conducted to verify the feasibility of this technique, demonstrating the potential to be applied in such fields as semiconductor and biochip, where the air gap may play crucial roles.
Abstract
Heart failure is the terminal stage of many cardiac diseases, in which β
1
-adrenoceptor (β
1
-AR) autoantibody (β
1
-AA) has a causative role. By continuously activating β
1
-AR, β
1
-AA ...can induce cytotoxicity, leading to cardiomyocyte apoptosis and heart dysfunction. However, the mechanism underlying the persistent activation of β
1
-AR by β
1
-AA is not fully understood. Receptor endocytosis has a critical role in terminating signals over time. β
2
-adrenoceptor (β
2
-AR) is involved in the regulation of β
1
-AR signaling. This research aimed to clarify the mechanism of the β
1
-AA-induced sustained activation of β
1
-AR and explore the role of the β
2
-AR/Gi-signaling pathway in this process. The beating frequency of neonatal rat cardiomyocytes, cyclic adenosine monophosphate content, and intracellular Ca
2+
levels were examined to detect the activation of β
1
-AA. Total internal reflection fluorescence microscopy was used to detect the endocytosis of β
1
-AR. ICI118551 was used to assess β
2
-AR/Gi function in β
1
-AR sustained activation induced by β
1
-AA in vitro and in vivo. Monoclonal β
1
-AA derived from a mouse hybridoma could continuously activate β
1
-AR. β
1
-AA-restricted β
1
-AR endocytosis, which was reversed by overexpressing the endocytosis scaffold protein β-arrestin1/2, resulting in the cessation of β
1
-AR signaling. β
2
-AR could promote β
1
-AR endocytosis, as demonstrated by overexpressing/interfering with β
2
-AR in HL-1 cells, whereas β
1
-AA inhibited the binding of β
2
-AR to β
1
-AR, as determined by surface plasmon resonance. ICI118551 biasedly activated the β
2
-AR/Gi/G protein-coupled receptor kinase 2 (GRK2) pathway, leading to the arrest of limited endocytosis and continuous activation of β
1
-AR by β
1
-AA in vitro. In vivo, ICI118551 treatment attenuated myocardial fiber rupture and left ventricular dysfunction in β
1
-AA-positive mice. This study showed that β
1
-AA continuously activated β
1
-AR by inhibiting receptor endocytosis. Biased activation of the β
2
-AR/Gi/GRK2 signaling pathway could promote β
1
-AR endocytosis restricted by β
1
-AA, terminate signal transduction, and alleviate heart damage.
Polymerase (RNA) II (DNA directed) polypeptide A (RPB1) is the largest subunit of RNA polymerase II (RNAPII), and phosphorylation of its C-terminal domain (CTD) is required for transcription ...initiation, elongation and RNA processing. Little is known about the CTD phosphorylation pattern and potential function during cell division when transcription is silenced. In this study, we assessed the protein expression and subcellular distribution of RPB1 during mouse oocyte meiotic division. Western blot analysis revealed that the RPB1 CTD was highly phosphorylated on Ser2 (pRPB1Ser2), Ser5 (pRPB1Ser5) and Ser7 (pRPB1Ser7). High and stable expression of pRPB1Ser2 and pRPB1Ser5 was detected from germinal vesicle (GV) to Metaphase II (MII) stage. In contrast, pRPB1Ser7 only emerged after germinal vesicle breakdown (GVBD) and gradually increased to its peak level at metaphase I (MI) and MII. Immunofluorescence demonstrated that pRPB1Ser2, pRPB1Ser5 and pRPB1Ser7 were pronouncedly aggregated within the nucleus of GV oocytes with a non-surrounded nucleolus (NSN) but very faintly labeled in oocytes with a surrounded nucleolus (SN). After meiotic resumption, pRPB1Ser2 was again detected at spindle poles and co-localized with key microtubule organizing center (MTOC) components, pericentrin and γ-tubulin. pRPB1Ser5 and pRPB1Ser7 were assembled as filamentous aggregates and co-localized with microtubules throughout the spindle structure, responding to spindle-disturbing drugs, nocodazole or taxol, in pattern strongly similar to microtubules. pRPB1Ser2 and pRPB1Ser5 were constantly localized on chromosomes, with a relatively high concentration in centromere areas. Taken together, our data suggest that the CTD is highly phosphorylated and may be required for accurate chromosome segregation in mouse oocytes during meiosis.
Structured illumination microscopy (SIM) has attracted many attentions due to high-precision, high-efficiency and strong adaptability. In most SIM, two essential parameters need to be accurately ...obtained to restore the 3D shape of the object which are the focus position of each pixel <inline-formula> <tex-math notation="LaTeX">\mathbf {z}_{\mathbf {max}} </tex-math></inline-formula> and the scan step <inline-formula> <tex-math notation="LaTeX">\boldsymbol {\Delta z} </tex-math></inline-formula>. For years, researchers have constantly improving the structure of SIM system to obtain more accurate <inline-formula> <tex-math notation="LaTeX">\mathbf {z}_{\mathbf {max}} </tex-math></inline-formula> to realize optimized measurement results. Meanwhile, the preset value of <inline-formula> <tex-math notation="LaTeX">\boldsymbol {\Delta z} </tex-math></inline-formula> is directly substituted into calculation. However, the actual value of <inline-formula> <tex-math notation="LaTeX">\boldsymbol {\Delta z} </tex-math></inline-formula> is very likely inconsistent with the preset value due to various factors in practical such as nonlinear motion of scan actuator, which will introduce great error into the measurement result. In this letter, a self-calibrated measurement method is proposed to resolve this problem. As we know, the full width at half maximum (FWHM) of the modulation curve is uniquely determined when the optical measurement system is determined. In this letter, a self-calibrated measurement method based on SIM (SC-SIM) is proposed and the determined FWHM is utilized to calculate the actual value of <inline-formula> <tex-math notation="LaTeX">\boldsymbol {\Delta z} </tex-math></inline-formula> to realize more accurate and reliable measurement result. Simulation and experiment are carried out to demonstrate the feasibility of the proposed method.
Due to wide applications, halophenols (HPs), especially bromophenols, chlorophenols, and fluorophenols, are commonly detected but resistant to biological removal in wastewater treatment plants ...(WWTPs). This study investigated the overall transformation behaviors of three representative HPs (2,4-dichlorophenol: 24-DCP, 2,4-dibromophenol: 24-DBP, 2,4-difluorophenol: 24-DFP) in six chemical oxidative systems (KMnO4, K2FeO4, NaClO, O3, UV, and persulfate (PS)). The results revealed fast removal of selected HPs by O3, PS and K2FeO4, while a large discrepancy in their removal efficiencies occurred under UV irradiation, KMnO4 oxidation and particularly chlorination. Based on the analysis of the identified intermediates and products, coupling among the five routes was the general route, and dimers were the main intermediates for HP oxidation. The effect of the halogen atom on the transformation pathways of HPs was highly reaction type dependent. Among the six chemical treatments, PS could induce HPs to yield relatively low-molecular-weight polymers and obtain the highest coupling degree. Transition state (TS) calculations showed that the H atom linked to the phenoxy group of HPs was the most easily abstracted by hydroxyl radicals to form the coupling precursor, i.e., phenoxy radicals. This high coupling behavior further resulted in the increased toxicity to green algae. Characterization revealed that HP reaction solutions treated with PS had a severely negative effect on algae growth, photosynthetic pigment synthesis, and the antioxidant enzyme system. These findings can shed light on the reaction mechanisms of advanced oxidation technologies and some risk management and control of PS technique may be considered when treating phenolic pollutants.
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•24-DCP was removed the fastest by chlorination but the lowest under UV irradiation.•Reaction types dominated the transformation pathways of HPs.•The highest coupling degree of HPs was observed in the PS treatment.•HP reaction solutions after treated with PS exerted high toxicity to S. obliquus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Scars are consequences of the wound healing process, and eliminating scar formation remains a significant challenge. Here, an injectable HMSC hydrogel was developed based on silk fibroin peptide ...grafted hydroxypropyl chitosan (HPCS-g-SFP) and oxidized microcrystalline cellulose (OMCC) via Schiff base bonds. The synthesized HPCS-g-SFP copolymer displayed efficient free radical scavenging ability on hydrogen hydroxyl radicals and 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). The pore size, gelling time, equilibrium swelling rate and water retention properties of HMSC hydrogel could be regulated by changing ratio of OMCC and HPCS-g-SFP. Then, tetramethylpyrazine (TMP) was encapsulated into HMSC hydrogel to obtain TMP-loaded HMSC hydrogel. The TMP-loaded HMSC hydrogel facilitated 95% cell activity retention after culturing with human skin fibroblasts (HSF) or human hypertrophic scar fibroblast (HSFB) cells for 24 h. Additionally, in vivo animal experiments confirmed that TMP-loaded HMSC hydrogel promoted rapid wound healing while preventing scar formation. The designed injectable TMP-loaded HMSC hydrogel has potentials in promoting scarless wound healing.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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