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Polymers of intrinsic microporosity (PIMs) have been the potential candidates as gas separation membrane materials, because of their high permeability and good processing. Here, three PIMs (PIM-ABA...

Spirobichroman-based polymers with high gas permeability and selectivity are promising for their applications as membranes in gas separation. In this study, three spirobichroman-based polyimides (PIs; 6FDA-FH, 6FDA-DH, and 6FDA-MH) were synthesised by the polyreaction between diamines containing different substituents (benzene ring, pyridine ring, and methyl group) and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The physical properties, gas transport behaviour, d-spacing, dihedral angle of molecules, and fractional free volume of the PIs were investigated through experiments and molecular simulations. The PIs exhibited excellent thermal stability and good solubility in common organic solvents. The gas permeability of the PIs was investigated; the results highlighted the critical role of the substituents in the enhancement of the gas separation performance of polymer membranes. Detailed analysis of the PIs showed that 6FDA-FH exhibits the highest gas permeability. This can be ascribed to the loose packing of the polymer chain owing to the increased dihedral angle between the two planes. However, the methyl substituent in 6FDA-MH disrupts the polymer chain packing rather than changing the dihedral angle between the two planes, thus enhancing the gas permeability of 6FDA-MH. Furthermore, 6FDA-DH exhibited the highest CO2/CH4 selectivity, which is attributed to the CO2 affinity of the polymer containing the pyridine unit.

The gas separation of polymers of intrinsic microporosity (PIMs) was enhanced by incorporating bipyrimidine (bpy) into the polymer (PIM-bpy-x) through the polycondensation of a novel tetraphenyl-bipyrimidine monomer. The structures of PIM-bpy-x were investigated with 1H NMR and FT-IR. Because of the excellent heat resistance imparted by the tetraphenyl-bipyrimidine unit, PIM-bpy-x displayed better thermal stability than did PIM-1. These polymers displayed large Brunauer-Emmett-Teller (BET) surface areas, ranging from 656 to 728 m2 g−1. The BET surface area of PIM-bpy-5 was 728 m2 g−1, which was similar to that of PIM-1 (774 m2 g−1). PIM-bpy-x exhibited excellent gas separation performance. PIM-bpy-5 showed the highest CO2 permeability (5141 barrer), which was much higher than that of PIM-1 (4234 barrer). The increase in CO2 permeability is due to the affinity between the N-rich bipyrimidine units and CO2. Furthermore, PIM-bpy-x also showed greater resistance to aging than did PIM-1. All of the above indicate that introducing bipyrimidine units into the polymers can enhance the gas separation performance of PIMs.

Proton exchange membrane (PEM) is a vital part of polymer electrolyte fuel cells (PEFCs). So it is of great importance to design the novel polymers for PEMs to improve the performance of PEFCs. Here two highly branched sulfonated copolymers (SBP-Cz-x) were synthesized based on a novel AB2 monomer. For all we know, it is the first time that the 9H site of carbazole was used to prepare branched polymers. These copolymers given tough and transparent membranes by solvent casting method. SBP-Cz-x membranes exhibited excellent thermal stability and remarkable dimensional stability. Moreover, proton conductivity of SBP-Cz-x was very excellent. SBP-Cz-15 (IEC = 1.33 meq.g−1) owned high proton conductivity of 42.1 mS cm−1 at 80 °C. SBP-Cz-15 showed a pretty low swelling ratio of 12.7% with high water uptake (32.0%). SBP-Cz-x also owned remarkable oxidation stability. This study demonstrated that the strategy of fixing locally dense sulfonic acid groups on the branched points, which were surrounded by hydrophobic segment, could improve oxidative stability and dimensional stability efficiently.

A new diamine monomer with a dioxinyl bipyrimidine group was synthesized. Polyimide containing a bipyrimidine group was successfully homopolymerized by chemical imidization. Analyses to determine the structure and properties of these polymers were conducted using 1H NMR and FTIR spectroscopy and gel permeation chromatography (GPC). For the first time, cobalt acetate was incorporated into the synthesized polyimide to fabricate cobalt-complexed polyimide thin film composite membranes (TFCMs) by spin coating. To fully understand the behavior of cobalt complexed TFCMs, these membranes were synthesized and then characterized by FTIR spectroscopy, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) to survey the effects of cobalt acetate on polyimide. The morphologies of TFCMs were determined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Phase separations and defects were absent in all cobalt-complexed TFCMs; the average thickness of the films ranged from 550 to 600 nm. This strongly suggested that cobalt acetate has good compatibility with bipyrimidine polyimide. The gas separation performance for TFCMs was also determined with the following results: the CO2 permeance of DMD-PI-3.0 (mixing 3.0 wt% cobalt acetate) TFCMs was 69.9 GPU at 35 °C and 1.5 bar while the selectivity of CO2/CH4 was 44.79 for DMD-PI-15 TFCMs. In short, this work reports a promising method to utilize the separation characteristics of polyimide TFCMs by incorporating cobalt ions.

Crystallized sulfonated poly(arylene ether ketone) (Cr-SPAEK) materials constructed from dense sulfonated hydrophilic segments and crystalline poly(ether ketone) (PEK) hydrophobic backbone were designed. The membrane exhibited considerable proton conductivity and superb solvent resistance owing to its special phase morphology, the presence of a broad hydrophilic ion transport channel, and a crystalline hydrophobic matrix. The dense sulfonated hydrophilic segment provides excellent proton conductivity; the Cr-SPAEK-20 membrane exhibits higher proton-conducting ability than Nafion 117 in the temperature range of 20–100 °C; its proton conductivity reaches about 168 mS cm–1 at 100 °C. The crystalline PEK hydrophobic segment ensures superior solvent resistance and dimensional stability, guaranteeing the durability of the membrane in practical applications. The methanol permeability of Cr-SPAEK-20 is only one-eighth that of Nafion 117 when the test conditions are the same. The direct methanol fuel cell (DMFC), ...

Magnetic tunnel junctions (MTJs) with ferromagnetic electrodes possessing the strong perpendicular magnetocrystalline anisotropy (PMA) are of great interest as they have a potential for realizing next-generation high-density non-volatile memory and logic chips. To date, it is an urgent and critical issue to continuously promote the PMAs through feasible modifications such as the substitution of ferromagnetic layers as well as the overlayer coating on them. Here, we perform the relativistic first principles calculations of TM|L10-FePt|MgO sandwich systems, and demonstrate that the changes in PMAs by capping TM layers are always giant and positive, e.g., PMA of Fe|FePt|MgO, the largest one among all our studied systems, is about 2 times larger than that of FePt|MgO. The interfacial PMAs at TM|FePt and FePt|MgO interfaces are extracted to be 3.31~9.40 meV and 3.32 meV, respectively, which are at least 3 times larger than 0.93 meV/ML of interior FePt layer. We illustratively verify that PMAs of TM|FePt|MgO can be turned in a large range by varying the TM layer and in-plane strain. Our results and model analyses provide useful insights for how these magnetic quantities are linked, and pave a way for the promotion of PMAs of FePt-based heterostructures via contact with TM overlayers.

We designed and synthesized two novel azobenzene functionalized poly(aryl ether)s (PAEs), PAE-azo-1 and PAE-azo-2, from a new azobenzene monomer via nucleophilic aromatic substitution polycondensation. This direct polymerization approach via azobenzene monomer has the advantages of controlling the distribution and amount of the azobenzene chromophores in the polymer. Both of the polymers showed very good thermal stability and excellent solubility for future application in the electronics industry. These polymers were fabricated as films by simple spin-coating and both of them were then prepared as sandwich memory devices. PAE-azo-1 and PAE-azo-2 exhibit write-once-read-many-times-type memory behavior, which can be encoded as “0” and “1,” and possess the low operation voltage below −3.0 V. The memory mechanism was investigated through ultraviolet–visible optical absorption spectrum and the cyclic voltammetry. These obtained results indicate that the novel azobenzene functionalized PAEs are a promising candidate for low power consumption and high-performance materials for data storage.

Zwitterionic poly(arylene ether sulfone) (PAES-NS) was synthesized via copolymerization by using a bisphenol monomer with a pyridine group. The chemical structures of the copolymers were confirmed by using Fourier transform infrared (FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopy; the copolymers showed good thermal stability. A series of polyphenysulfone (PPSU)/PAES-NS blend ultrafiltration (UF) membranes was prepared via conventional immersion precipitation phase inversion methods The morphologies of the modified membranes were investigated by scanning electron microscopy (SEM). The surface hydrophilicity of the UF membranes was studied by water contact angle measurement, indicating that the zwitterionic group increased the membrane hydrophilicity. UF of solvated model pollutants using the membranes showed a significant reduction of the irreversible adsorption of the foulants, illustrating the excellent anti-fouling properties of the membrane. The water flux of the PAES-NS membrane was significantly enhanced, being almost three times higher than that of the pristine PPSU membrane, with retention of a high rejection level. After three UF cycles, the water flux recovery of the PAES-NS membrane was as high as 96%.

The separation of organic solvents can be improved in a sustainable way by implementing membranes produced via streamlined processing. However, conventional membranes are not typically used in organic solvents, and thus require further chemical cross-linking before use. This process is complicated, and cross-linking agents are harmful to the environment. This study investigated the synthesis of a sulfonated poly(aryl ether ketone) (SPAEK) copolymer with a controlled degree of sulfonation via molecular design as a novel nanofiltration membrane in organic solvent. The introduction of a suitable number of sulfonic acid groups improved the hydrophilicity and surface charge of the membrane compared to conventional poly(aryl ether ketone) (PAEK), leading to excellent performance in separating alcoholic solvents and negatively charged dyes. The membrane still exhibited good separation performance, and no obvious damage to its microstructure was found by FESEM after the membrane was soaked in N,N-dimethylformamide (DMF) for 7 days. Consequently, the ethanol permeance and dye rejection of the membrane was maintained. PEK-SPEDEK membrane has potential applications in OSN under complex and harsh conditions such as printing, dyeing and pharmaceuticals.

A series of poly(arylene ether ketone)s (PAEKs) with dense sulfonic-acid-functionalized pendants were successfully synthesized by the Ullmann C–N coupling of a polymer precursor containing pendant iodobenzene rings and 3,6-ditrityl-9H-carbazole, followed by sulfonation using chlorosulfonic acid. A tough transparent membrane, which exhibited suitable dimensional stability and high proton conductivity, was obtained by casting an N,N-dimethylacetamide polymer solution. DSPAEK-CZ-25 (IEC = 2.03 meq. g−1, where IEC = ion-exchange capacity) exhibited the highest proton conductivity of 177 mS cm−1 at 100 °C; this value is significantly greater than that of Nafion 117. In terms of molecular design, the large difference in polarity between the fluorinated polymer backbone and the concentrated pendant sulfonic acid groups possibly induces good phase-separation morphology, which enhances conductivity and dimensional stability. The obtained membranes exhibited excellent thermal stabilities and good mechanical properties. Overall, the DSPAEK-CZ polymers exhibited outstanding comprehensive performance as potential materials for proton exchange membranes (PEMs).

MicroRNAs (miRNAs) play an important role in regulating cancer stem cell (CSC). Previous studies have shown that microRNA-221/222 (miR-221/222) cluster are involved in the propagation of breast cancer stem cell (BCSC), however, the underlying molecular mechanisms are still not fully understood. In this study, we found that miR-221/222 were overexpressed in highly aggressive breast cancer MDA-MB-231 cells, that are enriched in markers for epithelial-mesenchymal transition (EMT) and BCSCs, than in MCF-7 cells. Phosphatase and tensin homolog (PTEN) was confirmed to be the target of miR-221/222 in breast cancer cells. MiR-221/222 enhanced breast cancer cell growth, migration and invasion by downregulating PTEN. Importantly, both ectopic expression of miR-221/222 and PTEN knockdown increased the mammosphere formation capacity and the expression of the stemness marker ALDH1. MiR-221/222 lentivirus vector infected MCF-7 cells produced larger subcutaneous tumors, while shRNA vector of PTEN showed similar trend. Along with the downregulation of PTEN caused by miR-221/222 in the breast cancer cells and the xenograft tumor tissues, Akt phosphorylation (p-Akt), NF-κB p65 and phosphorylated p65 (p-p65), and cyclooxygenase-2 (COX-2) were all overexpressed compared to the negative control. Taken together, our findings indicate that miR-221/222 play a critical role in the propagation of BCSCs and tumor growth possibly through targeting PTEN, which in turn activating the Akt/NF-κB/COX-2 pathway. MiR-221/222 might represent the potential target of breast cancer therapy.

To overcome the trade-off between permeability and selectivity of polymeric membranes and understand the influence of ultra-rigid units on gas separation performance, a series of PIMs (PIM-EN-x) based on spirodifluoranthene (EN) have been prepared. These polymers showed outstanding thermal stability. Their 5% weight loss temperature is higher than 503 °C. PIM-EN-x owned high BET surface area, ranging from 804 to 895 m2 g-1. With the increase of EN units, the gas permeability increased. The CO2 permeability of PIM-EN-40 is 11512 barrer, which is increased by 172% compared to PIM-1 with no loss in selectivity. The gas separation performance of PIM-EN-x surpassed the 2008 upper bound and near the latest upper bound. This work put forward a special structural unit to prepare polymers for CO2 separation and natural gas sweetening.

Colorectal cancer (CRC) is one of the most common malignancies in the world. microRNA-140-5p (miR-140) has been shown to be involved in cartilage development and osteoarthritis (OA) pathogenesis. Some contradictions still exist concerning the role of miR-140 in tumor progression and metastasis, and the underlying mechanism is uncertain. Immunohistochemistry was performed to determine the expressions of ADAMTS5 and IGFBP5 in CRC tissues. Human CRC cell lines HCT116 and RKO were transfected with miR-140 mimic, inhibitor, or small interfering RNA (siRNA) against ADAMTS5 or IGFBP5, respectively, using oligofectamine or lipofectamine 2000. Scratch-wound assay and transwell migration and invasion assays were used to evaluate the effects of miR-140 on the capabilities of migration and invasion. The levels of miR-140 and ADAMTS5 and IGFBP5 mRNA were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was performed to examine the expression of ADAMTS5 and IGFBP5 proteins. miR-140 was significantly reduced, whereas ADAMTS5 and IGFBP5 were upregulated, in the human CRC tissues compared to the corresponding normal colorectal mucosa. miR-140 downregulation and ADAMTS5 or IGFBP5 overexpression were associated with the advanced TNM stage and distant metastasis of CRC. There was a reverse correlation between miR-140 levels and ADAMTS5 and IGFBP5 expression in CRC tissues. ADAMTS5 and IGFBP5 were downregulated by miR-140 at both the protein and mRNA levels in the CRC cell lines. The gain-of- and loss-of-function studies showed that miR-140 inhibited CRC cell migratory and invasive capacities at least partially via downregulating the expression of ADAMTS5 and IGFBP5. These findings suggest that miR-140 suppresses CRC progression and metastasis, possibly through downregulating ADAMTS5 and IGFBP5. miR-140 might be a potential therapeutic candidate for the treatment of CRC.

Multiple factors affecting the sulfonated poly (arylene ether) proton exchange membrane materials are worthy of being systematically explored. In order to investigate the variation of membrane materials based on ion exchange capacity (IEC) and hydrophilic segment length, three series of dense sulfonated poly (arylene ether)s (mt-SPAE-y, dt-SPAE-y and tt-SPAE-y) containing mono-, di- and tri-sulfonated tetraphenylmethane structural units were synthesized. Each series contains three sulfonated copolymers with different IEC values. Small angle X-ray scattering and transmission electron microscopy results show that increasing the IEC value is conducive to the aggregation of hydrophilic ion clusters, while the growth of hydrophilic segment length helps to the formation of larger hydrophilic ion clusters. Both variations favor the construction of connected hydrophilic ion channels. Based on the highest IEC value and the longest hydrophilic segment length, the tt-SPAE-1.94 membrane forms a connected hydrophilic channel that allows it to exhibit the highest proton conductivity and lowest activation energy of the proton conductivity. Good thermal properties, mechanical properties and oxidation resistance lay the foundation for the durability of the membrane in fuel cells. Finally, the tt-SPAE-1.94 membrane was used for membrane electrode assembly at 80 °C and 95% relative humidity, exhibiting a power density of 418 mW cm−2 in H2/air fuel cell test. In summary, both the increase in the IEC value and the length of the hydrophilic segment contribute to the formation of good hydrophilic-hydrophobic phase morphology, thereby enhancing the macroscopic properties of the sulfonated poly (arylene ether) proton exchange membrane material. The results prove that these three series of membranes show outstanding prospects in actual fuel cell operation and have considerable research value.

A precise quantification of insect chitin is needed in order to avoid overestimation of crude protein due to chitin-bound nitrogen. An UPLC/FLR method was optimized and validated for the determination of glucosamine (GlcN) hydrolyzed from chitin in insect materials. The method was applied for quantifying the chitin content in mealworms (Tenebrio molitor) and crickets (Acheta domesticus). A baseline separation was obtained using an Acquity HSS T3 C18 column, with an external calibration curve of excellent linearity, and a low limit of de-tection and quantification of GlcN. Even though the recovery of GlcN from spiked cricket material was slightly lower compared to that using spectrophotometric method, the UPLC/FLR method proved a sensitive and specific method of quantification of insect chitin. Chitin contents in T. molitor and A. domesticus were 4.6 +/- 0.1% and 4.5 +/- 0.0% on dry matter basis, respectively. Less than 0.01% of chitin was present in insect protein-enriched fractions extracted with 0.1 N NaCl at pH 10.

Poly (ether sulfone) (PES), as a kind of special engineering plastic, is widely used in the field of separation. However, its gas separation performance is unremarkable. Therefore, a series of PES containing the tetraphenyl bipyrimidine unit (PES-TPhbpy-x) was prepared by nucleophilic polycondensation to improve the gas separation performance of PES. PES-TPhbpy-x exhibited a high molecular weight, excellent mechanical properties, and could form robust membranes. With increasing TPhbpy unit content in PES-TPhbpy-x, the glass transition temperature and heat resistance increased. WAXD analysis revealed that the d-spacing of PES-TPhbpy-x is larger than that of PES. This indicated that the TPhbpy unit could hinder the polymer chain packing and enhance the rigidness of the polymers. Compared with PES, PES-TPhbpy-x exhibited an excellent gas separation performance. The CO2 permeability of the PES-TPhbpy-100 increased by 570%, and the CO2/N2 selectivity and CO2/CH4 selectivity increased by 49% and 50%, respectively. Moreover, PES-TPhbpy-100 could form a membrane by the hot-press method. The CO2 permeability of the PES-TPhbpy-100 membrane prepared by the hot-press method was 12.81 barrer. In addition, the CO2/N2 and CO2/CH4 selectivities were 32.0 and 37.7, which were 27% and 35% higher than those of the PES membrane, respectively.

Poly(arylene ether sulfone) (PES) consisting of a comb-shape chain state with various aliphatic side groups was designed and synthesized. The polymer maintained good thermal stability and chemical resistance, and its loose chain stacking was more suitable for membrane separation than that of commercial poly(arylene ether sulfone)s. The thermal performance test showed glass transition temperature decreased from 184 °C to 157 °C with increases in aliphatic chain size. All thermal decomposition temperatures of the polymer exceeded 450 °C. Separation membranes for water treatment or gas separation were prepared and tested. SEM results showed the thickness of the skin layer decreased when the aliphatic side group lengthened, leading to a notably higher water flux. Additionally, gas permeability of the membranes was at least twice that of pure PES. An increasing selectivity to methane was observed: for a longer comb-shape polymer membrane, the selectivity to methane continues to increase.

Four spirobichroman-based polyimides (6FDA-F, 6FDA-O, 6FDA-P, and 6FDA-M) were successfully obtained via polyreaction between diamines of different substituents (-H, -OCH3, -N, and -CH3) and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The molecular weights, thermophysical, dihedral angle of the molecules, fractional free volume, d-spacing, Brunauer–Emmett–Teller surface area, and gas separation performance were studied through a combination of experiments and molecular dynamics simulations. These polymers show high molecular weights, with number-average molecular weights (Mn) in the range of 5.0–15.3 × 104, and excellent thermal stability, with weight loss temperatures (T5%) of over 420 °C. The pure-gas (O2, N2, CO2, and CH4) permeation results indicated that the four polymers selectivity of CO2/CH4 over 31 and that 6FDA-F had the highest gas permeability among the four tested gases. Importantly, the dihedral angle from molecular simulation was used to clarify the phenomenon wherein the 6FDA-P gas permeability lower than 6FDA-F. A detailed analysis indicates that -CH3 increased the gas permeability of the polyimides, while the turnstile-like rotary thermal motion of -OCH3 formed channel obstacles and improved the gas selectivity. The polymers containing pyridine ring and those containing benzene ring follows different gas separation mechanisms, based on the gas solution-diffusion behaviour.

A cross‐linked structure is introduced into fluorinated poly(aryl ether) using nucleophilic substitution reaction at the ortho‐position of decafluorobiphenyl moieties in a fluorinated poly(aryl ether) molecular chain. Such a novel low dielectric material with excellent performances has important application value in the aerospace and the integrated electronics fields.

The advancement of proton conductive applications will require the identification of new membrane with high-conductivity and good dimensional stability that can be readily obtained and cheap. We reported a novel rigid carbazole derivative and proton exchange membrane consisting of densely sulfonated carbazole derivative, which could form aggregated ionic cluster of sulfonic acid group and result in continuous broad-dimensional nanochannels. The SAXS analysis confirmed these copolymers owned large ion clusters. All of membranes prepared in this work were thermally stable at up to 250 o C. These membranes also exhibited excellent dimensional stability and outstanding proton conductivity. SPESK-Cz-15 with IEC = 2.07 meq g -1 showed the largest water uptake with a value of 107%, but the swelling ratio was only 36.4% at 100 o C, which was attributed to the artful structure of the copolymers. SPESK-Cz-15 showed very high proton conductivity (165.3 mS cm -1 at 80 o C), which was 1.53 times higher than that of Nafion 117 (108 mS cm -1 at 80 o C). Besides, the maximum power density of SPESK-Cz-15 was 1642.7 mV cm -2 at 80 o C under 95% RH. The stability of single cell based on SPESK-Cz-15 was remarkable. All above indicate that SPESK-Cz-x are potential materials for polymer electrolyte membrane fuel cells in the future.

With the dramatic development of Web 2.0, the occurrence of online health communities (OHCs) appeal to increasing number of patients and physicians to involve in this new healthcare platform. Extant literature has primarily discussed the motivation of knowledge sharing from participants in OHCs. However, scant studies have been conducted to explore the motivations of doctors’ contribution behaviors in OHCs. Drawing on motivation theory, knowledge sharing theory and social capital theory, we mainly examine the effects of monetary and reputational incentives on doctors’ continuous participation in OHCs. In addition, we also investigate how online incentive factors and offline status of doctors can interact hereby motivating doctors to better serve in the OHCs. We will collect data from an OHCs in China. The findings will not only enrich the relevant theory, but also help us to understand physicians’ motivation mechanisms in OHCs.

Background Colorectal cancer (CRC) is one of the most common malignancies in the world. microRNA-140-5p (miR-140) has been shown to be involved in cartilage development and osteoarthritis (OA) pathogenesis. Some contradictions still exist concerning the role of miR-140 in tumor progression and metastasis, and the underlying mechanism is uncertain. Methods Immunohistochemistry was performed to determine the expressions of ADAMTS5 and IGFBP5 in CRC tissues. Human CRC cell lines HCT116 and RKO were transfected with miR-140 mimic, inhibitor, or small interfering RNA (siRNA) against ADAMTS5 or IGFBP5, respectively, using oligofectamine or lipofectamine 2000. Scratch-wound assay and transwell migration and invasion assays were used to evaluate the effects of miR-140 on the capabilities of migration and invasion. The levels of miR-140 and ADAMTS5 and IGFBP5 mRNA were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was performed to examine the expression of ADAMTS5 and IGFBP5 proteins. Results miR-140 was significantly reduced, whereas ADAMTS5 and IGFBP5 were upregulated, in the human CRC tissues compared to the corresponding normal colorectal mucosa. miR-140 downregulation and ADAMTS5 or IGFBP5 overexpression were associated with the advanced TNM stage and distant metastasis of CRC. There was a reverse correlation between miR-140 levels and ADAMTS5 and IGFBP5 expression in CRC tissues. ADAMTS5 and IGFBP5 were downregulated by miR-140 at both the protein and mRNA levels in the CRC cell lines. The gain-of- and loss-of-function studies showed that miR-140 inhibited CRC cell migratory and invasive capacities at least partially via downregulating the expression of ADAMTS5 and IGFBP5. Conclusions These findings suggest that miR-140 suppresses CRC progression and metastasis, possibly through downregulating ADAMTS5 and IGFBP5. miR-140 might be a potential therapeutic candidate for the treatment of CRC.

Ceramic ZrO2 and metallic Ti–6Al–4V alloy are jointed by using a Ti33Zr17Cu50 (at.%) amorphous alloy as a solder at 1123–1273 K in a high vacuum. It is demonstrated that the microstructure and mechanical properties are significantly influenced by the brazing temperature, the heat time and the cooling rate. The brazing seam jointing ZrO2 with Ti–6Al–4V is composed of ZrO2/Cu2Ti4O, (Ti,Zr)2Cu/TiO, Ti2O/CuTi2, (Ti,Zr)2Cu/CuTi2/Ti–6Al–4V alloys and compounds, of which the increasing thickness weakens the shear strength as the brazing temperature, the heat time the cooling rate increase. The maximum shear strength of the brazing joints reaches 162 MPa with the optimal technical parameters: the brazing temperature of 1173 K, the heat time of 10 min and the cooling rate of 5 K/min. The fracture of the joint occurs in the brittle seam layer nearby the side of ZrO2.

With the swift emergence of electronic medical information, the global popularity of mobile health (mHealth) services continues to increase steadily. This study aims to investigate the efficacy factors that directly or indirectly influence individuals' acceptance of mHealth services. Based on the technology acceptance model, this research incorporates efficacy factors into the acceptance decision process. A research model was proposed involving the direct and indirect effects of self-efficacy and response-efficacy on acceptance intention, along with their moderating effects. The model and hypotheses were validated using data collected from a field survey of 650 potential service users. The results reveal that: (1) self-efficacy and response-efficacy are both positively associated with perceived ease of use; and (2) self-efficacy and response-efficacy moderate the impact of perceived usefulness toward adoption intention. Self-efficacy and response-efficacy both play an important role in individuals' acceptance of mHealth services, which not only affect their perceived ease of use of mHealth services, but also positively moderate the effects of perceived usefulness on adoption intention. Our findings serve to provide recommendations that are specifically customized for mHealth service providers and their marketers.

Today, Infrared remote control technology has been applied to various aspects of our life and production. It is used not only in the high-end technology, such as aerospace, but also in all kinds of remote controls in our daily life. Therefore, the infrared remote control simulation system based on single chip microcomputer is designed. The remote control simulation system is mainly designed for household appliances requiring remote control. The design's overall task is that LED lights are switched on by the remote signal light. The direction from the LED light switched on by the remote signal light determines the on-off of the light relay switch, then determines the on-off of the external circuit. The design mainly consists of infrared emission and receiving end, STC89C51 microcontroller pin connection, LED display parts and the designing of relay hardware, then it will be tested and put into operation. It simulates how the relay switch and LED lights work according to the remote signal, and connects the LED display to the on-off of the external circuit.

Background The miR-221/222 cluster has been discovered to function as oncogene in human malignancies including breast cancer. However, the role of miR-221/222 in the self-renewal of breast cancer stem cells (BCSCs) is not fully understood. In this study, we examined the impact and mechanism of miR-221/222 on the breast cancer cell viability, migration and invasion, and propagation of BCSCs. Methods Human breast cancer cell line MCF-7 was transfected with miR-221/222 mimics or inhibitors to overexpress or knock down miR-221/222 respectively using Lipofactamine 2000. The biological effects of miR-221 and miR-222 were then assessed by cell proliferation assay, colony formation assay and transwell chamber assays. CD44/CD24 staining and mammosphere formation assay were performed to evaluate the ability of BCSCs self-renewal. Potential target gene phosphatase and tensin homolog (PTEN) and its downstream effector, phosphorylated Akt (p-Akt) were identified by Western blot and qRT-PCR methods. Results PTEN, a tumor suppressor gene, was confirmed as a target of miR-221/222 in breast cancer cell line MCF-7. Downregulation of PTEN by miR-221/222 increased the phosphorylation of Akt. Enforced expression of miR-221/222 promoted breast cancer cell proliferation, migration and invasion via targeting PTEN/Akt pathway. Importantly, ectopic expression of miR-221/222 enriched the proportion of CD44+/CD24− BCSCs and improved the mammosphere formation capacity through targeting PTEN/Akt pathway. Blocking the endogenous miR-221/222 restored PTEN expression and subsequently decreased Akt phosphorylation, and thereby reversed this phenotype. Conclusions Our results suggested that miR-221/222 enhance breast cancer growth, migration and invasion, meanwhile propagate the self-renewal of BCSCs. This is achieved possibly through targeting PTEN/Akt pathway. miR-221/222 might be a novel therapeutic candidate for human breast cancer.

Mobile health (m-health) services are becoming increasingly important and widely accepted. However, empirical studies on potential users' m-health acceptance behavior remain underexplored. Indeed, m-health adoption is not only a technology acceptance behavior, but also a health-related behavior.Based on the Protection Motivation Theory, this article explores users' m-health adoption behavior from the perspectives of threat appraisal and coping appraisal, and also examines the moderating role of gender and age through a survey of potential users. The survey was conducted among 500 potential m-health service participants.Our results show that threat appraisal and coping appraisal factors influence adoption intention through attitude. It is also found that gender and age play different moderating roles with threat appraisal and coping appraisal factors.Gender and age play different roles between threat appraisal and coping appraisal factors in the acceptance of m-health. Implications for research and practice are discussed.

To solve the problem of traditional C/S model which can't perform Cross-Platform perfectly, a design of instant communication system on the basis of B/S and C/S is proposed in this thesis. This system takes full advantage of Web2.0, exerts the advantages of B/S model and adopts popular Web technique: CSS combined with DIV, and Ajax asynchronous transmission; It uses excellent layered structure model: the data access layer, the business logic layer, the user interface layer; It applies input validation and character filtration for security so that SQL injection attack and other attacks can be avoided, thus the stability of the system can be ensured.

China's current low level of organization of farmers is not adapted to the economic development of rural markets which will make it difficult to improve peasant incomes. So it's important for China to improve the degree of farmers' organizations. The patterns mainly include cooperative organizations, contract model and intermediary model. These organizations also need government support and protection in addition to internal dynamics.

Farmers’ wish of cooperation has been swelled since 1900 with the development of rural market economy,especially with speeded agricultural industrialization and furious conflicts between peasants’ small-scaledproduction and large market. As China’s systematization is low for today, how to develop and perfect specializedfarmers cooperatives is very urgent. The thesis begins from the analysis of conditions, then investigates exitingproblems, finally puts forward feasible countermeasures.