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As a flexible protective material, shear thickening gel (STG)/Kevlar composite still has great potential to improve its impact resistance. In this paper, a novel STG/Si[O.sub.2]/Kevlar flexible protective composite was prepared by impregnating STG/Si[O.sub.2] into Kevlar. Due to the excellent Si[O.sub.2] enhancement effect, the STG/Si[O.sub.2]/Kevlar exhibited a higher safeguarding property than the STG/Kevlar. The maximum yam pull-out force of STG/Si[O.sub.2]/Kevlar reached 61.7 N, which was higher than the 41.9 N of STG/Kevlar. The uniform puncture results showed that the maximum bearing capacity of STG/Kevlar and STG/Si[O.sub.2]/Kevlar increased by 116.8% and 215.3%, respectively, compared with pure Kevlar. The impact test results indicated that 20 layers of STG/Si[O.sub.2]/Kevlar could not be penetrated by the knife stab and 24 layers of STG/Si[O.sub.2]/Kevlar could not be penetrated by 7.62 mm pistol bullets. Finally, the enhancement mechanism of impact resistance of STG/Si[O.sub.2]/Kevlar composites was studied. KEYWORDS composite material, impact resistance, particle enhancement, shear thickening gel (STG), 1 | INTRODUCTION Body armor or stab-resistant clothing is usually made of layers of high-performance fiber fabrics superimposed and sewn to achieve a protective effect, which seriously reduced the comfort [...]

The action of abscisic acid (ABA) is closely related to its level in plant tissues. Uridine diphosphate-glycosyltransferase71c5 (UGT71C5) was characterized as a major UGT enzyme to catalyze the formation of the ABA-glucose ester (ABA-GE), a reversible inactive form of free ABA in Arabidopsis thaliana (thale cress). UGTs function in a mode where the catalytic base deprotonates an acceptor to allow a nucleophilic attack at the anomeric center of the donor, achieving the transfer of a glucose moiety. The proteomic data revealed that UGT71C5 can be persulfidated. Herein, an experimental method was employed to detect the persulfidation site of UGT71C5, and the computational methods were further used to identify the yet unknown molecular basis of ABA glycosylation as well as the regulatory role of persulfidation in this process. Our results suggest that the linker and the U-shaped loop are regulatory structural elements: the linker is associated with the binding of uridine diphosphate glucose (UPG) and the U-shaped loop is involved in binding both UPG and ABA.It was also found that it is through tuning the dynamics of the U-shaped loop that is accompanied by the movement of tyrosine (Y388) that the persulfidation of cysteine (C311) leads to the catalytic residue histidine (H16) being in place, preparing for the deprotonation of ABA, and then reorientates UPG and deprotonated ABA closer to the 'Michaelis' complex, facilitating the transfer of a glucose moiety. Ultimately, the persulfidation of UGT71C5 is in favor of ABA glycosylation. Our results provide insights into the molecular details of UGT71C5 recognizing substrates and insights concerning persulfidation as a possible mechanism for hydrogen sulfide (H2S) to modulate the content of ABA, which helps us understand how modulating ABA level strengthens plant tolerance. [ABSTRACT FROM AUTHOR]

Polyimide (PI) has good mechanical properties and thermal stability, while high coefficient (COF) and wear rate limit its wide application. In order to endow PI with better friction and wear resistance, Mo2Ti2C3 MXene was used as solid lubricant to prepare Mo2Ti2C3/PI nanocomposites with different content of Mo2Ti2C3. The effect of the amount of Mo2Ti2C3 on the tribological behavior of PI was explored and the tribological mechanism was also analyzed Tribological tests showed that at 1.2 wt% of Mo2Ti2C3 addition, the composite material demonstrated superior friction and wear resistance, exhibiting a 19.9% decrease in the COF and a 79.7% decrease in the wear rate compared to single PI due to the good self‐lubricating properties of Mo2Ti2C3 MXene. Moreover, Mo2Ti2C3 can also effectively assist PI to form sleek transfer films without interruption or gaps on the steel balls, resulting in a reduced friction COF and wear rate of the material. This work demonstrates that Mo2Ti2C3 MXene is an aussichtsreich additive for polymers to improve the tribological properties and broadens the applications of Mo2Ti2C3/PI composites in friction material area. Highlights: Mo2Ti2C3 significantly improves the tribological performance of polyimide.The thermal properties of Mo2Ti2C3/polyimide are enhanced by the introduction of Mo2Ti2C3.The minimum coefficient of Mo2Ti2C3/PI composites was only 0.246 at the 1.2 wt% content of Mo2Ti2C3.The wear rate of Mo2Ti2C3/PI composites was decreased by 79.7% at the 1.2 wt% addition of Mo2Ti2C3.Mo2Ti2C3 promotes the establishment of tribo‐film to protect the Mo2Ti2C3/PI composites from friction. [ABSTRACT FROM AUTHOR]

Polyimide (PI) is a special engineering plastic, widely involved in mechanical components, instruments, and petrochemicals. However, single PI material is inevitably subject to wear and tear in practice, which leads to weakened material properties. In this work, Ti3C2Tx@SiO2 was prepared to enhance the wear resistance and lubrication properties of PI by intercalating SiO2 into the interlayer of Ti3C2Tx sheets. Ti3C2Tx@SiO2/PI composites were fabricated in two steps to test the tribological performances. SiO2 particles change the form of interfacial friction from sliding to rolling, thus relieving direct friction between material and steel ball. So, the composites have a minimum COF (COF = 0.33) when the content of Ti3C2Tx@SiO2 is 0.80 wt%. Moreover, the average value of wear rate was 0.24 × 10−5 mm3/(N·m) when Ti3C2Tx@SiO2 content was 1.60 wt%, which was 91.0% lower compared to the PI matrix. During the friction process, the abrasive chips of the material migrate to the surface of the steel ball to form a transfer film, which protects the material and thus reduces the wear rate. Therefore, the hybrids Ti3C2Tx@SiO2 are effective and important wear‐resistant agents and solid lubricants to improve the wear resistance and lubricity of PI or other polymer materials. Highlights: SiO2 insert Ti3C2Tx is a key factor in changing sliding friction into rolling friction, effectively reducing the COF.The average wear rate was 91.0% lower than that of the polyimide matrix when Ti3C2Tx@SiO2 content was 1.60 wt%.The minimum COF of Ti3C2Tx@SiO2/PI composites reached 0.33 when the content of Ti3C2Tx@SiO2 was 0.80 wt%.The transfer film effectively reduces further wear of the material during friction. [ABSTRACT FROM AUTHOR]

Thin‐thickness and lightweight electromagnetic wave (EMW) absorption materials are critically needed for stealth technology in the military stealth field. The special structure of a material is important for improving its good EMW absorption. Herein, a series of porous metal–organic framework‐derived LaCo/C‐decorated Ti3C2Tx (LaCo/C/Ti3C2Tx) composites are prepared by carbonization at high temperatures. Impressively, the minimum reflection loss of LaCo/C/Ti3C2Tx–2 is −47.72 dB at 10.26 GHz (thickness 2.3 mm), and the optimal effective absorption bandwidth is 5.45 GHz (thickness 1.9 mm). The excellent EMW absorption properties are due to multiple electromagnetic loss mechanisms, such as polarization loss, magnetic loss, and multiple reflections and scattering. This work provides a new route for the application of Ti3C2Tx‐based derivatives. [ABSTRACT FROM AUTHOR]

A series of polyimide (PI)/V2CTx MXene composites was synthesized via polyamide acids (PAA) and two‐dimensional (2D) V2CTx MXene obtained by etching precursor V2AlC. PI/V2CTx MXene composites with different mass ratios were obtained by blending and heating with PAA. The results showed that V2CTx MXene has excellent dispersion in PI. In particular, V2CTx MXene exhibited excellent friction reduction and anti‐wear properties as a solid lubricant additive, and the wear rate (WR) was reduced by 43.2% by incorporating only 0.8 wt% of V2CTx MXene in the pristine PI and 71.9% by incorporating 1.2 wt%. Scanning electron microscopy (SEM) and x‐ray photoelectron spectroscopy (XPS) analyses showed that the continuous transfer film consisting of a high proportion of tribo‐chemical products formed on the contact surface is significant to improve the lubrication performances of the PI composites. This work broadens the application of MXene in the field of tribology and contributes to energy conservation and sustainable development of human society. Highlights: The tribological properties could be tuned by changing the ratio of PI to V2CTx MXene.The WR of PI composites was reduced by 71.9% with incorporating 1.2 wt% of V2CTx MXene.The formation of transfer films on the contact surface is significant for improving anti‐wear of PI. [ABSTRACT FROM AUTHOR]

Context: The survival of patients diagnosed with osteosarcoma has not improved in the past three decades because of chemoresistance. Aim: This study aimed to improve the prognosis of patients with osteosarcoma. Settings and Design: From January 1, 2018, to June 30, 2019, a total of 14 patients with osteosarcoma were enrolled who underwent mini patient-derived xenograft (mini-PDX) assay in our hospital. Methods and Materials: We recruited 14 patients with osteosarcoma having acquirable lesions to establish PDX models and examine the sensitivity of nine drugs, including methotrexate (MTX), ifosfamide (IFO), epirubicin, and etoposide. Drug sensitivity was evaluated using the tumor relative proliferation rate (TRPR), and the patients' responses were assessed according to the RECIST 1.1 guidelines. Statistical Analysis Used: The difference in TRPR was analyzed using a paired t-test, while progression-free survival (PFS) was analyzed using the Kaplan–Meier method. Results: The mini-PDX results revealed that IFO had a lower tumor proliferation rate than MTX, indicating that IFO was more sensitive in patients with osteosarcoma (38.3% vs. 84.3%, P = 0.031). Thus, the regimen where IFO alternates with doxorubicin and cisplatin was recommended as adjuvant chemotherapy. MTX could replace IFO if the TRPR was better. Finally, 11 patients received adjuvant chemotherapy. A comparison of PFS revealed that sensitive patients with TRPR of <40% had a better prognosis (9.4 months vs. 3.7 months, P = 0.0324). Conclusions: Chemotherapy based on mini-PDX can improve the survival of patients with osteosarcoma whose TRPR was <40%, and that chemotherapy without MTX could be an alternative for osteosarcoma. [ABSTRACT FROM AUTHOR]

Summary Limited by spatial resolution and visual contrast, bone scintigraphy interpretation is susceptible to subjective factors, which considerably affects the accuracy and repeatability of lesion detection and anatomical localization. In this work, we design and implement an end-to-end multi-task deep learning model to perform automatic lesion detection and anatomical localization in whole-body bone scintigraphy. A total of 617 whole-body bone scintigraphy cases including anterior and posterior views were retrospectively analyzed. The proposed semi-supervised model consists of two task flows. The first one, the lesion segmentation flow, received image patches and was trained in a supervised way. The other one, skeleton segmentation flow, was trained on as few as five labeled images in conjunction with the multi-atlas approach, in a semi-supervised way. The two flows joint in their encoder layers so each flow can capture more generalized distribution of the sample space and extract more abstract deep features. The experimental results show that the architecture achieved the highest precision in the finest bone segmentation task in both anterior and posterior images of whole-body scintigraphy. Such an end-to-end approach with very few manual annotation requirement would be suitable for algorithm deployment. Moreover, the proposed approach reliably balances unsupervised labels construction and supervised learning, providing useful insight for weakly labeled image analysis. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]