Mechanical properties and wear resistance of medium entropy Fe40Mn40Cr10Co10/TiC composites

The Fe40Mn40Cr10Co10/TiC (volume fraction of TiC, 10%) composites were synthesized in combination of ball milling and spark plasma sintering (SPS) in the present work. Mechanical properties and wear resistance of the Fe40Mn40Cr10Co10/TiC composites were individually investigated. It was found that TiC particles homogenously distributed in the Fe40Mn40Cr10Co10/TiC composite after being sintered at 1373 K for 15 min. Meanwhile, grain refinement was observed in the as-sintered composite. Compared with the pure Fe40Mn40Cr10Co10 medium entropy alloy (MEA) matrix grain, addition of 10% TiC particles resulted in an increase in the compressive strength from 1.571 to 2.174 GPa, and the hardness from HV 320 to HV 872. Wear resistance results demonstrated that the friction coefficient, wear depth and width of the composite decreased in comparison with the Fe40Mn40Cr10Co10 MEA matrix. Excellent mechanical properties and wear resistance could offer the Fe40Mn40Cr10Co10/TiC composite a very promising candidate for engineering applications.

Malignant acanthosis nigricans with Leser–Trélat sign and tripe palms:A case report

BACKGROUND Acanthosis nigricans(AN),Leser–Trélat sign,and tripe palm are all skin diseases.To date,reports of these appearing as a paraneoplastic syndrome in a gastric cancer patient are quite rare.CASE SUMMARY We report the case of a 61-year-old man with darkened skin color in the face and torso with no obvious inducement after 1 year of treatment for Riehl’s melanosis.He had 40 brown maculopapular eruptions on his face and the top of his head with obvious itching.Papillary wart-like hyperkeratosis with dark brown pigmentation was also observed on both sides of the areola.He had papillomalike lesions on the face,around the orbit,and on the neck.His bilateral palms had small,smooth,papillary projections with millet-like appearance.Histopathological examination of the skin showed that the patient was suffering from AN,tripe palms,and Leser–Trélat sign.Gastroscopy showed the patient’s cardia was affected,and pathological biopsy revealed that he had moderate-to-poorly differentiated adenocarcinoma.Computed tomography test results showed that his cardia wall had thickened.Based on these histological and skin characteristics,the patient was diagnosed with gastric cancer with AN,tripe palms,and Leser–Trélat sign.CONCLUSION Researchers should follow up on patients with malignant AN,Leser–Trélat sign,and tripe palms.

Corrosion resistance and antibacterial properties of Ti−3Cu alloy prepared by selective laser melting

The corrosion resistance and antibacterial properties of Ti−3Cu alloy prepared by selective laser melting were evaluated using electrochemical experiments and a variety of antibacterial characterization.It is found that the charge transfer resistance of Ti−3Cu alloy was 4.89×10^(5)Ω∙cm^(2),which was doubled the data obtained by CP-Ti alloy.The antibacterial rates of Ti−3Cu alloy against S.mutans and P.gingivalis were 45.0%and 54.5%.And the antibacterial rates increased with the prolongation of cultivation time,reaching up to 62.8%and 68.6%,respectively.The in-situ nano Ti_(2)Cu precipitates were homogeneously distributed in the matrix of the Ti−3Cu alloy,which was the key reason of increasing the corrosion resistance.Additionally,the microscale electric fields between theα-Ti matrix and the Ti_(2)Cu was responsible for the enhancement of the antibacterial properties.

活性氧响应性核壳结构纳米粒子增加肿瘤富集与细胞摄取

微环境响应性高分子纳米药物可以大幅提升药物在肿瘤部位的特异性释放,降低在正常组织泄漏而引发副作用的风险,但肿瘤细胞对聚乙二醇化纳米药物较差的摄取能力极大降低了药效.本研究报道了一种可增强药物摄取并具有肿瘤微环境响应性的高分子模型药物递送体系,通过酯化反应得到胍基化改性罗丹明B,并将聚(L-谷氨酸)-接枝-聚(乙二醇)键合4-羟甲基苯硼酸频哪醇酯以得到ROS响应性高分子载体.之后将胍基化罗丹明B作为模型药物用响应性高分子载体担载,得到核壳状纳米粒子PgP-HA/RhoB-Gu NPs.体外释放与粒径变化结果表明,PgP-HA/RhoB-Gu NPs对ROS有良好的敏感响应性,细胞摄取结果表明,该胍基化罗丹明B可以更加高效被细胞摄取.体内分布可看出纳米粒子在肿瘤部位富集明显.通过纳米载体担载胍基化模拟药物同时实现肿瘤部位ROS响应性释放和增加细胞摄取的设计,为纳米药物更好地发挥药效提供了有效的策略.

Functional Amphiphilic Poly(2-oxazoline)Block Copolymers as Drug Carriers:the Relationship between Structure and Drug Loading Capacity

Poly(2-oxazoline)(POx)is a kind of polymeric amides that can be viewed as conformational isomers of polypeptides with excellent cyto-and hemo-compatibility,and is promising to be used as drug carriers.However,the drug loading capacity(DLC)of POx for many drugs is still low except several hydrophobic ones including paclitaxel(PTX).Herein,we prepared a series of amphiphilic POx block copolymers with various functional groups,and investigated the relationship between functional structures and the DLC.Functional POxs with benzyl,carboxyl,and amino groups in the side-chain were synthesized based on a poly(2-methyl-2-oxazoline)-block-poly(2-buty1-2-oxazoline-co-2-buteny1-2-oxazoline)(PMeOx-P(nBuOx-co-ButenOx),PMBEOx)precursor,followed by click reaction between vinyl and the 2-phenylethanethiol,thioglycolic acid and cysteamine.Using thin-film hydration method,eight commonly used drugs with various characteristics were encapsulated within these functional POx polymers.We found that amine-containing drugs were more easily encapsulated by POx with carboxyl groups,while amine functionalities in POx enhanced the loading capacity of drugs with carboxyl groups.In addition,n-n interactions resulted in enhanced DLC of most drugs,except several hydrophobic drugs with aromatic to total carbon ratios less than 0.5.In general,we could successfully encapsulate all the selected drugs with a DLC%over 10%using properly selected functional POxs.The above results confirm that the DLC of polymeric carriers can be adjusted by modifying the functional groups,and the prepared series of functional POxs provide an option for various drug loadings.

IL-2-loaded Polypeptide Nanoparticles for Enhanced Anti-cancer Immunotherapy

Interleukin 2 (IL-2) is widely used as an active immunotherapeutic agent in clinical metastatic cancers. However, its therapeutic concentrations do not last long due to its short half-life. Thus, only a transient proliferation of the anti-cancer CD8+ T cells can be achieved, resulting in poor efficacy. Therefore, the aim of this work was to create a system that promotes CD8+ T cell proliferation at the tumor site using IL-2 persistently present and activates an anti-cancer immune response. This goal was achieved by the design of the IL-2-loaded polypeptide nanoparticles (P-IL-2) where methoxy poly(ethylene glycol) block poly-[(N-2-hydroxyethyl)-aspartamide] phenylboronic acid was used to encapsulate IL-2 through boron-nitrogen coordination with poly(L-lysine). P-IL-2 significantly prolonged the circulation time of IL-2 and achieved a selective drug release at the tumor site in the presence of high levels of reactive oxygen species, thus activating an anti-cancer immune response and exerting a better anti-cancer effect. The half-life of P-IL-2 was 3.15-fold higher than that of IL-2, and the quantity of CD8+ T cells after using P-IL-2 was 1.89-fold higher than that after using IL-2. In addition, the combination of P-IL-2 and anti-CTLA-4 monoclonal antibody resulted in an enhanced immune activation. Hence, this work provides a new approach to improve the efficacy of IL-2 in anti-cancer immunotherapy.

Thermal-sprayed coating of optimally mixed ceramic powders on stainless steel with enhanced corrosion resistance

Three different groups of ceramic powders for the thermal-swayed coating were firstly prepared using sintering and ball milling. Then, these powders were separately deposited on three stainless steel substrates, followed by individual corrosion resistance examination. Microstructural characterization showed that the levels of micro-void and micro-crack at the bonding interface （between coating and substrate） depended on the proportions of different ceramic particles. Meanwhile, a significantly enhanced corrosion resistance was reproducibly observed in one group of as-coated samples that have the optimal combination of given ceramic powders. Furthermore, the mechanism of corresponding enhanced corrosion resistance was discussed. It was found that the optimal ceramic powders for the present thermal-sprayed coating should contain 30.2 wt% SiO2, 54 wt% Cr2O3, 6.8 wt% Al2O3, 4.8 wt% CaO and 1.8 wt% TiO2. The corrosion velocities of such samples in the 3.5 vol.% HCl, 15 wt% NaOH and 5 wt% NaCl solutions were 3.74, 2.98 and 0.50 g h-1 m-2 for 168, 336 and 336 h, respectively.

A Novel CA4P Polymeric Nanoparticle for Murine Hepatoma Therapy

Combretastatin A4 phosphate(CA4P)is a potent vascular disrupting agent with good water solubility.However,it is only effective at high doses,which decreases clinical applicability.Herein,we designed stable CA4P polymeric nanoparticles(CA4P NPs)consisting of various cholesterol derivatives,and with a drug loading efficacy of 93%.The nanoparticles released CA4P in a sustained manner and achieved a 72%inhibition rate in the murine H22 liver tumor model,which was about 2.9-fold higher than that of free CA4P(24.6%).Furthermore,the carrier components of CA4P NPs were metabolized to arginine,cholesterol,ethanol and poly(ethylene glycol)in vivo;therefore,the CA4P NPs are safe and have significant potential for clinical translation.