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In this paper, the flat roof Trough Condenser (FRTC) model is studied using a wind tunnel high frequency dynamic force measurement experiment. The Trough Condenser’s (TC) wind (torque) coefficients were obtained in six azimuths. The regularity and features of the wind coefficient when changing within a horizontal wind azimuth angle of 0°~360° and tilt angle of 0°~90° were analyzed. In addition, the TC on the flat roof and the TC installed on the ground were compared and analyzed. The results showed that the FRTC’s resistance coefficient, lift coefficient and fundament tilting torque coefficient are all much greater than the side force coefficient, side torque coefficient and azimuth torque coefficient. When designing the TC’s structure, the main consideration is the influence of resistance, fundament tilting torque and lift force. The maximal value of the resistance coefficient is 0.938, the maximal fundament tilting torque coefficient is 0.869, and the maximal value of the lift coefficient is −0.620. In addition, compared with the TC on the ground, the roof’s resistance coefficient is 67.39% lower, the lift coefficient is 130.65% lower and the fundament tilting torque coefficient is 68.01% lower. Furthermore, as the wind field on the roof is different from that on the ground, while the height of the condenser is lower, and the parapet shields the condenser to a certain extent, the maximum wind (torque) coefficient is also different when under different working conditions. Finally, the effect of the cone vortex on the roof’s edge also impacts these results.

Poly (γ-glutamic acid) (γ-PGA) has been found widespread applications in biomedical field because of its excellent water solubility, biocompatibility, and bioactivity. Herein, a water-insoluble γ-PGA antibacterial compound is facilely fabricated via one-pot electrostatic assembly of γ-PGA with cationic ethyl lauroyl arginate (ELA). The functionalized γ-PGA compound (γ-PGA-ELA) ethanol solution can facilely produce colorless and transparent coatings on various inorganic, metal, and polymeric substrates, especially for the lumen of slender catheters (length up to 2 m, and inner diameter down to 1 mm). The functionalized γ-PGA coating presents remarkable antibacterial efficacy in vitro and in vivo. In addition, the γ-PGA compound is used as antibacterial additives of polyolefin via melting extrusion, and the as-prepared antibacterial polyolefin demonstrates advantageous antibacterial efficacy. More importantly, the functionalized γ-PGA coating exhibit good hemocompatibility, low cytotoxicity, and satisfactory histocompatibility. The as-proposed γ-PGA compound has a great potential to serve as a safe and multifunctional antibacterial candidate to combat biomedical devices-related infections.

Nanoparticles (NPs) have been gaining prominence as delivery vehicles for modulating immune responses to improve treatments against cancer and autoimmune diseases, enhancing tissue regeneration capacity, and potentiating vaccination efficacy. Various engineering approaches have been extensively explored to control the NP physical and chemical properties including particle size, shape, surface charge, hydrophobicity, rigidity and surface targeting ligands to modulate immune responses. This review examines a specific set of physical and chemical characteristics of NPs that enable efficient delivery targeted to secondary lymphoid tissues, specifically the lymph nodes and immune cells. A critical analysis of the structure-property-function relationship will facilitate further efforts to engineer new NPs with unique functionalities, identify novel utilities, and improve the clinical translation of NP formulations for immunotherapy.

A series of ABA-type triblock copolymers (PImBF4-b-PPG-b-PImBF4) comprising of poly(propylene glycol) (PPG) as middle block and UCST polypeptide on both sides of PPG was synthesized by ring-opening polymerization of γ-chloropropyl-L-glutamic acid-based N-carboxyanhydride (CPLG-NCA) and then side-chain modification including nucleophilic substitution of the chloro group followed by copper-mediated 1,3-dipolar cycloaddition and subsequent ion-exchange reaction. Variable-temperature UV–vis spectroscopy revealed that the upper critical solution temperature (UCST)-type cloud point temperature (Tcp) was highly dependent on both polypeptide and PPG chain length as well as polymer concentration. Increasing the polymer chain length or concentration frequently results in Tcp increases. Noticeable hysteresis in a cooling/heating cycle was observed for all resulting triblock copolymers owing to a slow disassembly of large aggregates (d = 145 nm) in the heating cycle. Moreover, the resulting UCST triblock copolymers were used to regulate the release property of ciprofloxacin (CIP)-loaded poly(vinyl alcohol) (PVA) hydrogel. The incorporation of PImBF4-b-PPG-b-PImBF4 hampered the burst release of CIP at 37 °C indicating their potential toward sustained release of drug-loaded hydrogels.

Nanoparticular system of a model small molecular drug curcumin (CUR) was prepared using a novel method, namely, flash nanocomplexation by hydrogen bonding interactions. The CUR-loaded nanoparticles (NPs) were fabricated by mixing CUR, tannic acid and polyvinyl alcohol (PVA) in aqueous solutions under turbulent condition through a three-inlet confined impinging jet (CIJ) device. Compared to bulk mixing, FNC has the advantage of scalability, reproducibility and without causing the variations by different mixing sequences. Three NPs with different drug loading levels were prepared by tuning the CUR feeding amount. In human prostate cancer PC3 cells, both cellular uptake and cytotoxicity of these NPs were negatively correlated with the drug loading level. These findings indicate that FNC is an easy and feasible method for small molecular drug delivery by hydrogen bonding interactions.

The understanding of molecular structure and thermoresponsive property relationships and development of water-soluble thermoresponsive polymers with tunable cloud point temperatures (Tcps) are crucial toward versatile practical uses. Herein, OEGylated polypeptides bearing Y-shaped pendants, namely poly(γ-4-(propoxycarbonyl)benzyl-L-glutamate)-oligo(ethylene glycol) conjugates (8-OEGx, x = 2, 3) were synthesized by the combination of ring-opening polymerization of γ-4-(allyloxycarbonyl)benzyl-L-glutamic acid based N-carboxyanhydride (4) and subsequent side-chain modifications, including bromination of poly(γ-4-(allyloxycarbonyl)benzyl-L-glutamate) (5), nucleophilic substitution of 5 in the presence of NaN3, and subsequent copper-mediated 1,3-dipolar cycloaddition. Both 1H NMR and FTIR analysis confirmed the molecular structures of the intermediates and 8-OEGx. In aqueous solutions, 8-OEGx samples showed reversible lower critical solution temperature (LCST)-type phase transitions in broad polymer concentration range (0–30 mg·mL−1). Variable-temperature UV–vis spectroscopy results revealed that the LCST-type Tcp of 8-OEG2 at high polymer concentrations (e.g., ≥10 mg∙mL−1) was in the range of 37.5–42.5 °C. 8-OEG2 showed a remarkable increase of hydrophilicity than PBLG-OEG4 with the same amount of OEG units as well as linear shaped pendants. The Tcp of OEGylated polypeptides increased by addition of NaI, yet it decreased upon addition of NaCl, NaBr, or KCl, which obeys the Hofmeister effect.

OEGylated homopolypeptide (i.e., P(Azo-S-OEG7)) bearing azobenzene, thioether spacers, and oligo(ethylene glycol) OEG tails were prepared via a copper-mediated 1,3-dipolar cycloaddition. P(Azo-S-OEG7) showed an upper critical solution temperature (UCST)-type thermo-, light-, and oxidation-responsive in ethanol/water solvent mixtures. The UCST-type cloud point temperature (Tcp) decreased after UV irradiation and it increased after visible light irradiation due to the trans-cis isomerization of azobenzene moieties. P(Azo-S-OEG7) can be readily oxidized in the presence of H2O2, yielding P(Azo-SOX-OEG7) with sulfone or sulfoxide spacers. P(Azo-SOX-OEG7) showed an increase of UCST-type Tcp after UV irradiation and the Tcp decreased after visible light irradiation, which is an opposite trend to the UCST-type phase behavior of P(Azo-S-OEG7) as well as previous report. P(Azo-S-OEG7) showed poor water-solubility, yet it underwent H2O2 induced solution phase transition yielding P(Azo-SOX-OEG7) with lower critical solution temperature (LCST)-type phase behavior in water. The P(Azo-SOX-OEG7) aqueous solutions showed a decrease of LCST-type Tcp after UV irradiation and consequently Tcp decreased after visible light irradiation.

SO2-responsive homopolypeptide with tri(ethylene glycol), 1,2,3-triazole linkages and N-butylimidazolium iodide pendants (P4) were prepared by the ring-opening polymerization of γ-2-(2-(2-chloroethoxy)ethoxy)ethyl- l -glutamic acid based N-carboxyanhydride then post-polymerization to the side-chain, by the nucleophilic substitution of the chloro group in the presence of NaN3, followed by the copper-mediated 1,3-dipolar cycloaddition, and subsequent ion-exchange reaction. 1H NMR analysis revealed that SO2 interacted with 1,2,3-triazole group leading to polymer aggregation. The P4/SO2 aqueous solution is multi-responsive that can be triggered by gas (N2/SO2), temperature, and oxidation (i.e., H2O2). Poly(vinyl alcohol) (PVA) hydrogel modified by P4 and BaSO3 particles were prepared, the resulting hydrogel showed improved mechanical properties in terms of both stiffness and toughness.

Modelling hydraulic fracturing processes in shale oil and gas development remains a major challenge for industrial applications. The omission of heterogeneity inherent in the shale matrix may be one of the causes for the divergence between simulated fractures and those in reality. To elucidate the effects of heterogeneity on hydraulic fracturing, a workflow is developed for generating heterogeneous fields of hydraulic and geomechanical properties based on relatively easily available compressional wave velocity and shear wave velocity. After that, the workflow is implemented in our thermo-hydro-mechanical simulator for hydraulic fracturing. With the integrated simulator, the following are investigated: the effect of heterogeneity and the interactive effects of heterogeneity with other factors, i.e., in-situ stress gradient and stress shadow, the significance of different levels of heterogeneity, and the impact of various injection rates. The simulation results showed that these factors could have either synergetic or competitive effects under different circumstances. Also, different levels of heterogeneity result in different patterns of fractures’ geometry. According to our study, a heterogeneity field with a large coefficient of variation (CV) and medium correlation length (CL) turns out to develop fractures of the most complex patterns. Moreover, the high injection rate leads to neutralization of the influence of heterogeneity through the averaging effect of intense fracturing. The study leads to better understandings in the mechanism of hydraulic fracturing process under complicated factors such as heterogeneity, interactive effects, fracturing strategies, and both modes of rock failure. This study may shed light on future research on hydraulic fracturing and possible applications in practice as well as some improvements in designing hydraulic fracturing simulator.

Poly(vinyl alcohol) (PVA)-polypeptide double-network hydrogels with various ionic liquid (IL)-based polypeptides were prepared by a freezing/thawing method. Tensile tests revealed that the stiffness and toughness of the PVA hydrogels were significantly improved (e.g., 6.3 times the Young’s modulus and 5.8 times the work of extension) by incorporation of IL-based polypeptides. An optimized mechanical property was achieved by incorporation of α-helical imidazolium-based polypeptides at x = 0.03. Rheological tests revealed a thermally induced transition at 51.4–58.1 °C for the double network PVA/PPLG-ImBF4-x-67 (x = 0.01, 0.02, 0.03) hydrogels due to the rupture of the electrostatic interactions. Field emission scanning electron microscopy (FESEM) and wide-angle X-ray diffraction (WAXD) results suggested that the strong and tough double-network hydrogel was constructed by PVA crystallites and ionic bonds of IL-based polypeptide as the double physical cross-linkers.

Water-soluble homopolypeptides bearing di(ethylene glycol) (DEG) linkages and various ionic liquid (IL) pendants with both lower and upper critical solution temperature (LCST and UCST) or a UCST were prepared and systematically investigated. Poly (γ-2-(2-chloroethoxy)ethyl l -glutamate) (PCEELG) with DEG linkage and reactive chloro groups can be readily prepared from ring-opening polymerization of γ-2-(2-chloroethoxy)ethyl l -glutamic acid based N-carboxyanhydride. Homopolypeptides were conjugated with various IL pendants and counteranions by nucleophilic substitutions and subsequent ion-exchange reactions. Homopolypeptide with DEG linkages and tributylphosphonium iodide (PEELG-TBP-I) showed interesting LCST

Intervertebral disc (IVD) degeneration is a common disease that represents a significant cause of socio-economic problems. Bone marrow-derived mesenchymal stem cells (BMSCs) are a potential autologous stem cell source for the nucleus pulposus regeneration. Kaempferol has been reported to exert protective effects against both osteoporosis and obesity. This study explored the effect of kaempferol on BMSCs differentiation and inflammation. The results demonstrated that kaempferol did not show any cytotoxicity at concentrations of 20, 60 and 100μM. Kaempferol enhanced cell viability by counteracting the lipopolysaccharide (LPS)-induced cell apoptosis and increasing cell proliferation. Western blot analysis of mitosis-associated nuclear antigen (Ki67) and proliferation cell nuclear antigen (PCNA) further confirmed the increased effect of kaempferol on LPS-induced decreased viability of BMSCs. Besides, kaempferol elevated LPS-induced reduced level of chondrogenic markers (SOX-9, Collagen II and Aggrecan), decreased the level of matrix-degrading enzymes, i.e., matrix metalloprotease (MMP)-3 and MMP-13, suggesting the osteogenesis of BMSC under kaempferol treatment. On the other hand, kaempferol enhanced LPS-induced decreased expression of lipid catabolism-related genes, i.e., carnitine palmitoyl transferase-1 (CPT-1). Kaempferol also suppressed the expression of lipid anabolism-related genes, i.e., peroxisome proliferators-activated receptor-γ (PPAR-γ). The Oil red O staining further convinced the inhibition effect of kaempferol on BMSCs adipogenesis. In addition, kaempferol alleviated inflammatory by reducing the level of pro-inflammatory cytokines (i.e., interleukin (IL)-6) and increasing anti-inflammatory cytokine (IL-10) via inhibiting the nucleus translocation of nuclear transcription factor (NF)-κB p65. Taken together, our research indicated that kaempferol may serve as a novel target for treatment of IVD degeneration.

Polyelectrolyte complexes (PECs) are attractive soft materials with many promising applications, such as drug delivery and coatings. Study on the solution properties of α-helical polypeptide based PECs are still rare. Herein, new PECs composed of α-helical sulfonium-based polypeptides (PPBLG-DMS-I) and polysaccharides (i.e., carboxymethyldextran sodium salt, CMD) were prepared and investigated on their solution property. PPBLG-DMS-I were synthesized by an ultrafast ring-opening polymerization (ROP) and subsequent alkylation of methylthio groups with high grafting efficiency. The aggregation size of the polypeptide-polysaccharide based PECs was in the range of 450–600 nm at room temperature depending on the cationic/anionic weight ratios (RCAs) and polypeptide concentrations. It decreased by about 300 nm with increasing of the temperature by 40 °C. PEC solutions showed salt induced sharp phase transitions accompanied by the formation of coacervate droplets at low salt concentrations (e.g., 1.5 mg·mL−1). pH induced phase transitions of PEC solutions at both acidic (e.g., pH = 2.5) and basic conditions (e.g., pH = 11.5).

PM2.5 particles are regarded as prominent risk factors that contribute to the development of atherosclerosis. However, the composition of PM2.5 is rather complicated. This study aimed to provide a model particle that simulates the behavior of actual PM2.5, for subsequent use in exploring mechanisms and major complications arising from PM2.5. To establish model particles of PM2.5, a series of monodisperse SiO2 microspheres with different average grain diameters were mixed according to the size distribution of actual PM2.5. The organic carbon (OC) was removed from PM2.5 and coated onto the SiO2 model particle, to formulate simulant PM2.5. Results showed that the size distribution of the model particle was highly approximate to that of the PM2.5 core. The polycyclic aromatic hydrocarbon (PAHs) composition profile of the simulated PM2.5 were approximate to PM2.5, and loading efficiency was approximately 80%-120%. Furthermore, compared to the control, SiO2-only model particle had negligible cytotoxicity on cell viability and oxidative stress of HUVECs, and marginal effect on the lipid metabolism and atherosclerotic plaque formation in ApoE-/- mice. In contrast, simulated PM2.5 exhibited similar cytotoxic and detrimental effects on lipid metabolism and atherosclerotic plaque formation with actual PM2.5. Traffic-related PM2.5 had negative effects on endothelial function and led to the formation of atherosclerosis via oxidative stress. The simulated PM2.5 simulated the outcomes of actual PM2.5 exposure. Here, we show that SiO2 particle model cores coated with OC could significantly assist in the evaluation of the effects of specific organic compositions bound on PM2.5, specifically in the context of environmental health and safety.

Polypeptides bearing imidazolium and p -tolyl groups have been synthesized by click chemistry between poly(γ-3-azidopropyl- l -glutamate) (PAPLG) and 3-butyl-1-propargyl imidazolium bromide (BPIB) and 1-methyl-4-prop-2-ynyloxybenzene (MPB). The FTIR results revealed α -helical conformation of all resulting polypeptides in the solid-state. POM and WAXS study revealed that polypeptides with high p -tolyl contents (molar percentage ⩾54%) possessed nematic liquid crystalline phases and hexagonal packing in the solid-state. DSC analysis revealed the solid to liquid crystalline transitions in the temperature range of 35–42 °C.

The application of non-viral gene delivery vectors is often accompanied with the poor correlation between transfection efficiency and the safety profiles of vectors: vectors with high transfection efficiencies often suffer from high toxicities, making it unlikely to improve their efficiencies by increasing the DNA dosage. In the current study, we developed a ternary complex system which consisted of a highly membrane-active cationic helical polypeptide (PVBLG-8), a low-toxic, membrane-inactive cationic helical polypeptide (PVBLG-7) capable of mediating mannose receptor targeting, and DNA. The PVBLG-7 moiety notably enhanced the cellular uptake and transfection efficiency of PVBLG-8 in a variety of mannose receptor-expressing cell types (HeLa, COS-7, and Raw 264.7), while it did not compromise the membrane permeability of PVBLG-8 or bring additional cytotoxicities. Because of the simplicity and adjustability of the self-assembly approach, optimal formulations of the ternary complexes with a proper balance between membrane activity and targeting capability were easily identified in each specific cell type. The optimal ternary complexes displayed desired cell tolerability and markedly outperformed the PVBLG-8/DNA binary complexes as well as commercial reagent Lipofectamine™ 2000 in terms of transfection efficiency. This study therefore provides an effective and facile strategy to overcome the efficiency-toxicity poor correlation of non-viral vectors, which contributes insights into the design strategy of effective and safe non-viral gene delivery vectors.

Poly(γ-4-((2-(piperidin-1-yl)ethyl)aminomethyl)-benzyl-l-glutamate) (PPABLG), a cationic helical polypeptide, has been recently developed by us as an effective non-viral gene delivery vector. In attempts to elucidate the effect of molecular architecture on the gene delivery efficiencies and thereby identify a potential addition to PPABLG with improved transfection efficiency and reduced cytotoxicity, we synthesized PEG-PPABLG copolymers with diblock, triblock, graft, and star-shaped architectures via a controlled ring opening polymerization. The PPABLG segment in all copolymers adopted helical structure; all copolymers displayed structure-related cell penetration properties and gene transfection efficiencies. In HeLa and HepG-2 cells, diblock and triblock copolymers exhibited reduced membrane activities and cytotoxicities but uncompromised gene transfection efficiencies compared to the non-PEGylated, homo-PPABLG. The graft copolymer revealed lower DNA binding affinity and membrane activity presumably due to the intramolecular entanglement between the grafted PEG segments and charged side chains that led to reduced transfection efficiency. The star copolymer, adopting a spherical architecture with high density of PPABLG, afforded the highest membrane activity and relatively low cytotoxicity, which contributed to its potent gene transfection efficiency that outperformed the non-PEGylated PPABLG and Lipofectamine™ 2000 by 3–5 and 3–134 folds, respectively. These findings provide insights into the molecular design of cationic polymers, especially helical polypeptides towards gene delivery.

Three novel allyl–maleimide monomers (i.e., A 2 B, AB and AB 2 ) were designed, synthesized and thermally cured to yield a series of high-performance allyl–maleimide resins. All the monomers obtained are readily soluble in common organic solvents enabling an easy solution processing. The thermal properties of the three monomers were studied by the differential scanning calorimetry (DSC). A 2 B and AB showed fairly low melting temperature ( T m 2 B, PAB and PAB 2 ) was studied by the thermogravimetric analysis (TGA). Dynamic mechanical analysis (DMA) was used to investigate the dynamic mechanical properties of the composites based on the cured allyl–maleimide resins. PA 2 B and PAB 2 showed good glass transition temperatures ( T g > 270 °C) and their corresponding composites showed high bending modulus ( E ′ > 1900 MPa). Allyl-compound-modified BMI resins based on AB monomer were prepared. Rheometer revealed that the processability of the prepolymer (BR–AB-pre) was improved by the addition of AB monomer. The cured BMI resins (BR and BR–AB) showed good thermal stability ( T d > 400 °C, both in nitrogen and in the air), high glass transition temperature ( T g > 320 °C), and good mechanical properties and low water uptake (

In research towards high performance polymeric materials, two novel series of bismaleimide (BMI) resins based on 1,3,4-oxadiazole-containing monomers have been designed and prepared by the copolymeriziation reaction of 5-tert-butyl-1,3-bis[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]benzene (Buoxd) or 4,4′-bis[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]diphenyldimethylsilane (Sioxd) and 4,4′-bismaleimidodiphenylmethane (BMDM) in different feed ratios. The structures, thermal and dynamic mechanical properties of all the resulting BMI resins were carefully characterized by a combination of methods such as IR, DSC, TGA and DMA. Investigation of the copolymerization process has shown that with an increase of the weight ratio of Buoxd or Sioxd, melting transition temperature (Tm) of BMI monomer mixtures decreased and the exothermic polymerization temperature (Tp) increased. For all BMI monomer mixtures, a rapid polymerization process was observed in the early stage, as shown by the IR investigations. No glass transition was observed for the resulting BMI resins in the temperature range from 50 °C to 350 °C, indicating the formation of highly cross-linking networks. The initial thermal decomposition temperatures (Td) of the BMI resins were in the range of 477–493 °C in nitrogen and 442–463 °C in the air. Dynamic mechanical analysis (DMA) of the composites made of the BMI resins and glass cloth showed high bending modulus not only at room temperature (E′, 1.9–5.3 GPa) but also at high temperature, e.g., 400 °C (E′, 1.7–4.4 GPa).

Two novel bismaleimide (BMI) monomers containing 1,3,4-oxadiazole, i.e., 5- tert -butyl-1,3-di[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]benzene (Buoxd) and 4,4′-[5-(4-maleimidophenyl)-1,3,4-oxadiazole-2-yl]diphenyldimethylsilane (Sioxd), were designed, synthesized and copolymerized with 4,4′-bismaleimidodiphenylmethane (BMDM) to yield a new series of high-performance bismaleimide resins. Both monomers obtained are readily soluble in common organic solvents, such as dichloromethane and chloroform, enabling an easy solution processing. The thermal properties of the two monomers were carefully studied by the differential scanning calorimetry (DSC), optical microscopy and thermogravimetric analysis (TGA, simultaneous DSC). The BMI resins based on a mixture of Buoxd (or Sioxd) and BMDM in a weight ratio of 10% were prepared. DSC investigations showed that the thermal curing of the BMI resins could be accomplished at a lower temperature than the thermal curing temperatures of Buoxd and Sioxd, and the thermal processing window, i.e., the temperature range between the melting transition and thermal curing process, was over 26 °C. The thermal properties and thermal mechanical properties of the resulting BMI resins were investigated by DSC, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). No glass transition temperature was found in the range of 50–350 °C, and very good thermal stability ( T d > 490 °C in nitrogen) and high thermo-oxidative stability ( T d > 460 °C in air) were revealed. Composites composed of the above BMI resins and glass cloth were also prepared, which showed high bending modulus (>1.6 GPa) at a very high temperature (e.g., 400 °C).