Three-in-one DNA nanowheels for simultaneous tumor regression and drug resistance prevention in breast cancer model

Herein,we proposed novel three-in-one DNA nanowheels with simultaneous chemo and gene therapy to treat tumor,especially to prevent simultaneous drug resistance,which could be disassembled via a cascaded hybridization reactions triggered by the highly expressed microRNA in cancer cells for smart and efficient cancer therapy.Typically,with breast cancer as a model,microRNA 21 could trigger the self-disassembly of DNA nanowheel 1 via hybridization with a specially designed oligonucleotide(anti-microRNA 21)in DNA nanowheel 1,releasing another special oligonucleotide(Contact sequence)to trigger the self-disassembly of DNA nanowheel 2 with releasing of a special oligonucleotide(anti-Contact sequence)to trigger the self-disassembly of DNA nanowheel 1 cyclically,and thus the cascaded hybridization reactions with three-in-one anti-cancer functions could be generated based on three main therapeutic effects via releasing doxorubicin to inhibit macromolecular biosynthesis,antisense oligonucleotide of microRNA 21 to activate the apoptotic cell pathway and antisense oligonucleotide of MDR1 to prevent the drug resistance respectively.As expected,the proposed method showed improved therapeutic efficacy on the cancer cells with about 80%apoptosis ratio,especially on the drug resistant cancer cells with about 75%apoptosis ratio,compared with that in the conventional anti-cancer systems of about 70%on cancer cells and below 40%on drug resistant cancer cells,respectively.Most importantly,this strategy opened the door for generation of complex functional DNA-based structures for target triggering drugs releasing system combining with chemo-and genetherapy to generate tumor regression and prevent drug resistance with an optimized therapeutic efficacy,providing a new avenue for efficient cancer treatment,especially drug resistant cancers.

Knowledge mapping visualization analysis of the military health and medicine papers published in the Web of Science over the past 10 years

Background:Military medicine is a research field that seeks to solve the medical problems that occur in modern war conditions based on public medicine theory.Methods:We explore the main research topics of military health and medical research in the Web of Science?core collection(Wo SCC)from 2007 to 2016,and the goal of this work is to serve as a reference for orientation and development in military health and medicine.Based on Cite Space III,a reference co-citation analysis is performed for 7921 papers published in the Wo SCC from 2007 to 2016.In addition,a cluster analysis of research topics is performed with a comprehensive analysis of high-yield authors,outstanding research institutions and their cooperative networks.Results:Currently,the research topics in military health and medicine mainly focus on the following seven aspects:mental health diagnoses and interventions,an army study to assess risk and resilience in service members(STARRS),large-scale military action,brain science,veterans,soldier parents and children of wartime,and wound infection.We also observed that the annual publication rate increased with time.Wessely S,Greenberg N,Fear NT,Smith TC,Smith B,Jones N,Ryan MAK,Boyko EJ,Hull L,and Rona RJ were the top 10 authors in military health and medicine research.The top 10 institutes were the Uniformed Services University of the Health Sciences,the United States Army,the United States Navy,Kings College London,Walter Reed National Military Medical Center,Boston University,Walter Reed Army Institute of Research,Walter Reed Army Medical Center,Naval Health Research Center,and the VA Boston Healthcare System.Conclusion:We are able to perform a comprehensive analysis of studies in military health and medicine research and summarize the current research climate and the developmental trends in the Wo SCC.However,further studies and collaborations are needed worldwide.Overall,our findings provide valuable information and new perspectives and shape future research directions for further research in the area of military health and medicine.

Evaluation of polarization field in InGaN/GaN multiple quantum well structures by using electroluminescence spectra shift

In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11.4 nm, and 6.5 nm are experimentally studied. All of the EL spectra present a similar blue-shift under the low-level current injection,and then turns to a red-shift tendency when the current increases to a specific value, which is defined as the turning point.The value of this turning point differs from one another for the three InGaN/GaN MQW samples. Sample A, which has the GaN barrier thickness of 21.3 nm, shows the highest current injection level at the turning point as well as the largest value of blue-shift. It indicates that sample A has the maximum intensity of the polarization field. The red-shift of the EL spectra results from the vertical electron leakage in InGaN/GaN MQWs and the corresponding self-heating effect under the high-level current injection. As a result, it is an effective approach to evaluate the polarization field in the InGaN/GaN MQW structures by using the injection current level at the turning point and the blue-shift of the EL spectra profiles.

Influence of carrier gas H2 flow rate on quality of p-type GaN epilayer grown and annealed at lower temperatures

In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effectively decrease with appropriately reducing the carrier gas H2flow rate, and a high-quality p-type GaN layer could be obtained at a comparatively low annealing temperature by reducing the carrier gas H2flow rate. Meanwhile, it is found that the intensity and wavelength of DAP peak are changed as the annealing temperature varies, which shows that the thermal annealing has a remarkable effect not only on the activation of acceptors but also on the compensation donors.

Thermal analysis of GaN-based laser diode mini-array

Thermal characteristics of multiple laser stripes integrated into one chip is investigated theoretically in this paper. The temperature pattern of the laser diode mini-array packaged in a TO-can is analyzed and optimized to achieve a uniform temperature distribution among the laser stripes and along the cavity direction. The temperature among the laser stripes varies by more than 5 K if the stripes are equally arranged, and can be reduced to less than 0.4 K if proper arrangement is designed. For conventional submount structure, the temperature variation along the cavity direction is as high as 7 K, while for an optimized trapezoid submount structure, the temperature varies only within 0.5 K.

Effect of Droop Phenomenon in InGaN/GaN Blue Laser Diodes on Threshold Current

Electroluminescence （EL） and temperature-dependent photolumineseenee measurements are performed to study the internal quantum efficiency droop phenomenon of blue laser diodes （LDs） before lasing. Based on the ABC mode, the EL result demonstrates that non-radiative recombination rates of LDs with threshold current densities of 4 and 6kA/cm2 are similar, while LD with threshold current density of 4kA/cm2 exhibits a smaller auger- like recombination rate compared with the one of 6kA/cm2. The internal quantum efficiency droop is more serious for LD with higher threshold current density. temperature-dependent photoluminescence is consistent The internal quantum efficiency value estimated from with EL measurements.

Analysis of localization effect in blue-violet light emitting InGaN/GaN multiple quantum wells with different well widths

Four blue-violet light emitting InGaN/GaN multiple quantum well（MQW） structures with different well widths are grown by metal–organic chemical vapor deposition. The carrier localization effect in these samples is investigated mainly by temperature-dependent photoluminescence measurements. It is found that the localization effect is enhanced as the well width increases from 1.8 nm to 3.6 nm in our experiments. The temperature induced PL peak blueshift and linewidth variation increase with increasing well width, implying that a greater amplitude of potential fluctuation as well as more localization states exist in wider wells. In addition, it is noted that the broadening of the PL spectra always occurs mainly on the low-energy side of the PL spectra due to the temperature-induced band-gap shrinkage, while in the case of the widest well, a large extension of the spectral curve also occurs in the high energy sides due to the existence of more shallow localized centers.

Simultaneously Improved Curing,Mechanical,Antioxidative Properties and Reduced ZnO Loading of Silica Filled NR Composites by Incorporation of Low-cost Crude Carbon Dots via Conventional Melt-milling Method

Rubbers or elastomers play an important role in hi-tech technology and civilian daily life because of their unique and strategical properties.Generally,the rubber additives are essential components for rubbers’practical application.Nowadays,developing novel multifunctional additives has attracted increasing research attention.In this work,low-cost crude carbon dots(CCDs)were used as multifunctional additives for natural rubber/silica system(without any additional modification)through industrial compatible melt-mixing method.The results revealed that the CCDs could disperse well in the NR/silica system,and they could not only endow the rubber compound with excellent anti-aging capability due to CCDs’radical scavenging activity because of their plenty of nitrogen-containing species,but also improve the curing rate and mechanical performance of the rubber composite.Also,the CCDs could reduce the rolling resistance of the rubber composites(tanδvalue at 7%strain of the rubber composite could be decreased by 34%),which is promising for the application of energy-saving tire industry.Lastly,the addition of CCDs could effectively reduce the ZnO dosage by at least 40%in the rubber composite without deteriorating its performance.Overall,this work provides valuable guidance to develop novel cheap yet effective additives for the elastomer.

生态环境高分子的研究进展

生态环境高分子是指全生命周期内低环境负荷甚至没有环境负荷的一类环保高分子.作为响应自然呼唤的高分子,生态环境高分子诞生于20世纪90年代高分子工业飞速发展的年代,目前已经成为高分子科学的前沿研究方向.我国学者以可再生资源的单体为核心(但不限于该类单体),从催化剂设计、可控聚合方法、聚合物性能调控、聚合物功能化、物理表征和加工方法等方面取得了一系列重要的创新成果,有力推动了世界范围内该研究领域的发展.本综述以聚乳酸等8类典型生态环境高分子为例,总结和评述了最近30年我国学者在生态环境高分子领域的基础研究进展,并对其未来发展趋势进行了展望.

Phase-change composite filled natural nanotubes in hydrogel promote wound healing under photothermally triggered drug release

It is of great importance to treat a bacterial-infected wound by a smart dressing capable of delivering antibiotics in a smart manner without causing drug resistance.The construction of smart release nanocontainers responsive to near-infrared(NIR)laser irradiation in an on-demand and stepwise way is a promising strategy for avoiding the emergence of multidrug-resistant bacteria.Here,we develop a hydrogel composite made of alginate and nanotubes with an efficient NIR-triggered release of rifampicin and outstanding antibacterial ability.This composite hydrogel is prepared through co-encapsulating antibacterial drug(rifampicin),NIR-absorbing dye(indocyanine green),and phase-change materials(a eutectic mixture of fatty acids)into halloysite nanotubes,followed by incorporation into alginate hydrogels,allowing the in-situ gelation at room temperature and maintaining the integrity of drug-loaded nanotubes.Among them,the eutectic mixture with a melting point of 39℃ serves as the biocompatible phase-change material to facilitate the NIR-triggered drug release.The resultant phase-change material gated-nanotubes exhibit a prominent photothermal efficiency with multistep drug release under laser irradiation.In an in vitro assay,composite hydrogel provides good antibacterial potency against Staphylococcus aureus,one of the most prevalent microorganisms of dangerous gas gangrene.A bacterial-infected rat full-thickness wound model demonstrates that the NIR-responsive composite hydrogel inhibits the bacteria colonization and suppresses the inflammatory response caused by bacteria,promoting angiogenesis and collagen deposition to accelerate wound regeneration.The NIR-responsive composite hydrogel has a great po-tential as an antibacterial wound dressing functionalized with controlled multistep treatment of the infected sites.

Bubble-templated Construction of Three-dimensional Ceramic Network for Enhanced Thermal Conductivity of Silicone Rubber Composites

With the continuous development of the electronics industry,the energy density of modern electronic devices increases constantly,thus releasing a lot of heat during operation.Modern electronic devices take higher and higher request to the thermal interface materials.Achieving high thermal conductivity needs to establish an interconnecting thermal conductivity network in the matrix.For this purpose,the suspension of Al203 and curdlan was first foamed to construct a bubble-templated continuous ceramic framework.Owing to the rapid gelation property of curdlan,we can easily remove moisture by hot air drying.Finally,the high thermally conductive composites are prepared by vacuum impregnation of silicone rubber.The result showed that composites prepared by our method have higher thermal conductivity than the samples obtained by traditional method.The thermal conductivity of the prepared composite material reached 1.253 W·m^(-1)·K·^-(1)when the alumina content was 69.6 wt%.This facile method is expected to be applied to the preparation of high-performance thermal interface materials.

Morphologies and Mechanical Properties of Cis-1,4-butadiene Rubber/Polyethylene Blends

The mechanical properties and phase morphologies of cis-1,4-butadiene rubber（BR） blended with polyethylene（PE） at different blend ratios were studied. The tensile test results show that the PE exhibits excellent reinforcing capabilities towards BR. Blending BR with PE results in a remarkable enhancement of tensile strength, modulus and the elongation at break simultaneously. An increment of tensile strength from 1.11 MPa to 16.26 MPa was achieved by incorporation of 40 wt% PE in the blends. The modulus and elongation at break of 40/60 PE/BR blends are also about 5 times higher than those of the pure BR treated under exactly the same conditions. The tear test indicates that the tear strength also increases with the increase of PE content. It reaches 58.38 MPa for the 40/60 PE/BR blend, which is approximately 10 times higher than that of the pure BR. Morphological study demonstrates that the PE forms elongated microdomains finely dispersed in the BR matrix when its content is over 30 wt%, which corresponds to the remarkably enhanced mechanical properties.According to the results, reinforcement mechanism of PE toward BR dependent on the microstructure has been discussed and two different mechanisms have been proposed.

Phase Structure and Crystallization Behavior of Polyethylene in Its Blends with cis-1,4-Butadiene Rubber

Phase structure and crystallization behavior of polyethylene （PE） in its blends with cis-1,4-butadiene rubber （BR） at different blend ratios and sample preparation conditions were studied. The PE is finely dispersed in the BR matrix. For samples hot pressed at 145 ℃, circular PE microdomains with randomly oriented PE lamellar aggregates were produced. The domain size and number increase with increasing PE content. When the PE content is over 10 wt%, most of the PE domains impinged each other. The separated PE domains are connected by PE stripes with parallel arranged lamellar aggregates. For samples hot pressed at 140 ℃, elongated PE microdomains with oriented PE lamellar aggregates were obtained due to the shear flow. The crystallization of PE in the blends depends on the phase structure. Confined crystallization of PE occurs in small microdomains at relatively low temperature. With the increase of domain size, the crystallization ability of PE increases while the confined crystallization decreases.

Access to quality diagnosis and rational treatment for tuberculosis: real-world evidenee from China-Gates Tuberculosis Control Project Phase Ⅲ

Background:China has successfully reduced tuberculosis(TB)incidence rate over the past three decades,however,challenges remain in improving the quality ofTB diagnosis and treatment.I n this paper,we assess the effects of the implementation of"China National Health Commission(NHC)and Gates Foundation TB Preventi on and Control Pro-jectwon the quality ofTB care in the three provinces.

Dispersion and Filler Network Structure of Fibrillar Silicates in Elastomers

The dispersion and filler network of fibrillar silicate（FS） in elastomers were studied. The results showed that a good dispersion of FS in matrix during mechanical blending in unvulcanized composites contributed to a strong FS filler network, different from that of traditional reinforcing fillers. Meanwhile, the filler re-aggregation during vulcanization caused by the overlapping and intertwining of FS further strengthened the filler network. The factors including Mooney viscosity and molecular polarity of elastomer, type and amount of silane coupling agents used for filler modification, that may influence the filler network, were studied. Our study helps us to understand the mechanism for the formation of filler network of FS in elastomers and provides guidance for the preparation of high performance FS/elastomer composites.

Theoretical Interpretation of Conformation Variations of Polydimethylsiloxane Induced by Nanoparticles

There has been controversy as to whether the addition of nanoparticles to a polymer melt causes perturbed chain structure of polymers. In this work, the chain conformations of polydimethylsiloxane（PDMS） with addition of polyhedral oligomeric silsesquioxane（POSS） nanoparticles have been studied using a classical density functional approach. Under the strong interactions of POSS-PDMS, the radius of gyration of PDMS in the nanocomposites can either increase or decline depending on particle loading. After adding nanoparticles with larger size or weaker interactions, both the increasing and the declining amplitudes can be largely suppressed. The results provide a deep understanding of chain conformation in polymer nanocomposites.

Tuning the Electrically Conductive Network of Grafted Nanoparticles in Polymer Nanocomposites by the Shear Field

Contolling the formation of the conductive network in the polymer nanocomposites(PNCs)is very meaningful to enhance their electrical property.In this work,we investigated the effect of grafted nanoparticles(NPs)on the conductive probability of PNCs in the quiescent state as well as under the shear field via a coarse grained molecular dynamics simulation.It is found that the smallest percolation threshold is realized at the moderate grafting density,the moderate length of grafted chains or the moderate interaction between grafted chains and free chains.Corresponding to it,the dispersion state of NPs varies from the contact aggregation to the uniform dispersion.By analyzing the connection mode among NPs,the probabilty of NPs which connect three other ones reaches the maximum value at their moderate dispersion state which is responsible for the optimal conductive probability.In addition,the main cluster size is characterized to better understand the conductive network which is consistent with the percolation threshold.It is interesting to find that the percolation threshold is smaller under the shear field than under the quiescent state.The shear field induces more NPs which connect three other ones.This benefits the formation of the new conductive network.Meanwhile,the anisotropy of the conductive probability is reduced with increasing the grafting density.In summary,this work provides a clear picture on how the conductive network of grafted NPs evolves under the shear field.

Excellent Compatibilization Effect of a Dual Reactive Compatibilizer on the Immiscible MVQ/PP Blends

Methyl vinyl silicone rubber (MVQ)/polypropylene (PP) thermoplastic vulcanizate (TPV) combines the good melt processability, recyclability and sealing performance as well as biosafety, stain and fluid resistance, and thus it is especially suitable in bio-safety areas and wearable electronic devices, etc. Nevertheless, the compatibility between MVQ and PP phases is poor. A big challenge on the compatibilization of MVQ/PP blends is that neither MVQ nor PP contains any reactive groups. In this study, a dual reactive compatibilizer composed of ethylenemethyl acrylate-glycidyl methacrylate terpolymer (EMA-co-GMA) and maleic anhydride grafted polypropylene (PP-g-MAH) was designed for the compatibilization of MVQ/PP blends. During melt blending, a copolymer compatibilizer at the MVQ/PP interface can be formed because of the in situ reaction between EMA-co-GMA and PP-g-MAH. The thermodynamic predict of its compatibilization effect through calculating the spreading coefficient of the in situ formed copolymer indicates that it can well compatibilize MVQ/PP blends. The experimental results show that under the GMA/MAH molar ratio of 0.5/1, the interface thickness largely increase from 102 nm for non-compatibilized blend to 406 nm, and the average size of MVQ dispersed phase largely decreases from 2.3 µm to 0.36 µm, the Tg of the two phases shifts toward each other, the mixing torque and mechanical properties of the blend are increased, all indicating its good compatibilization effect. This study provides a good compatibilizing method for immiscible MVQ/PP blends with no reactive groups in both components for the preparation of high performance MVQ/PP TPVs.

Epoxidation Functionalized Isobutylene Isoprene Rubber toward Green-curing Pathway and High-performance Composites

Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties,and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system.In this contribution,a novel modified product of isobutylene isoprene rubber(IIR),epoxyfunctionalized IIR(EIIR)was successfully prepared by in situ epoxidation technique for the first time,and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride(MAH)without additional additives.The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process.Under optimal condition,the degree of epoxidation of the rubber reached around 99%without side reactions.The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites.More importantly,compared with IIR composites,the air-tightness of the EIIR composites was improved by about 50%,and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times.The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.

Polyurethane-polysiloxane Copolymer Compatibilized SiR/TPU TPV with Comfortable Human Touch Toward Wearable Devices

Because of its softness,wear resistance,biocompatibility,extremely comfortable human touch,thermoplastic vulcanizate(TPV)comprised of silicone rubber(SiR)and thermoplastic polyurethane(TPU)(SiR/TPU TPV)is especially suitable for wearable intelligent devices.Nevertheless,developing good compatibilizer is still required to prepare high performance SiR/TPU TPV.In this study,three kinds of polyurethane-polysiloxane copolymer(PU-co-PSi)with different contents of polysiloxane segment were selected,and their compatibilization effect on SiR/TPU blends was studied using nanomechanical mapping technique of AFM.The results show that using PU-co-PSi with the highest content of polysiloxane segment(PU-co-HPSi),the interface thickness largely increases,and the average size of SiR dispersed phase largely decreases,indicating its good compatibilization effect.By using PU-co-HPSi as compatibilizer,SiR/TPU TPV with a fine SiR dispersed phase and good mechanical performance were successfully prepared.The mechanism on the compatibilization effect of these PU-co-PSi on SiR/TPU TPVs was revealed.