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Two unprecedented spiro-bridged PPAPs, hyperispirones A and B (1 and 2), were isolated and characterized from the aerial parts of Hypericum beanii.

Despite Si-based materials and their derivatives have recently emerged as potential electrode materials in advanced energy conversion and storage applications, a review article has not been reported hitherto for Si-based supercapacitors. In this review, the representative progresses of Si-based materials have been illustrated including synthesis, properties, surface modification, and electrochemical properties. A variety of nanomaterials are presented regarding the electrode material design and booming device constructions. Effective strategies for the preparation of Si-based materials and their derivatives are summarized especially including silicon/silicon carbide nanowires, silicon substrates, silicon particles, three-dimensional silicon structures, and silicon-based doping materials. Meanwhile, the overall behaviors in supercapacitor application have been illustrated in terms of specific capacitance, rate capability, cycling life, and energy density. Furthermore, large-voltage microsupercapacitors are outlined for next-generation integration devices.

Fuzi (Aconitum carmichaelii Debx) has been traditionally used for the treatment of ulcerative colitis (UC) in China for thousands of years. The total alkaloids of A. carmichaelii (AAC) have been considered as the main medicinal components of fuzi, whereas its underlying anti-UC mechanisms remain elusive. In the present study, the dextran sulfate sodium (DSS)-induced UC mice model, which was consistent with the symptoms and pathological features of human UC, was established to comprehensively evaluate the anti-UC effects of AAC. The results indicated that AAC effectively improved the weight loss, disease activity index (DAI), spleen hyperplasia, and colon shortening, and thus alleviated the symptoms of UC mice. Meanwhile, AAC not only inhibited the MPO enzyme and the abnormal secretion of inflammatory cytokines (TNF-α, IL-1β, IL-6, IFN-γ, and IL-17A) and suppressed the overexpression of inflammatory mediators (TNF-α, IL-1β, and IL-6) of mRNA but also reduced the phosphorylation of p38 MAPK, ERK, and JNK, and the protein expressions of NF-κB, IκB-α, STAT3, and JAK2 in the colon tissue. Furthermore, the LC-MS/MS quantitative determination suggested that the three low toxic monoester alkaloids were higher in both contents and proportion than that of the three high toxic diester alkaloids. Additionally, molecular docking was hired to investigate the interactions between alkaloid-receptor complexes, and it suggested the three monoester alkaloids exhibited higher binding affinities with the key target proteins of MAPK, NF-κB, and STAT3. Our finding showcased the noteworthy anti-UC effects of AAC based on the MAPK/NF-κB/STAT3 signaling pathway, which would provide practical and edge-cutting background information for the development and utilization of A. carmichaelii as a potential natural anti-UC remedy.

A kind of hierarchical porous carbon (HCN) with three-dimensional network frameworks was successfully prepared by solvent-free nanocasting method using glucose as carbon source and ordered MCM-41 type of mesoporous silica with the different particle sizes as template. Meanwhile, its structure features and texture parameters were characterized by using XRD, N2 adsorption-desorption isotherms, SEM and TEM, FT-IR, Raman spectrum, XPS techniques. These results demonstrated that during the process of pyrolysis glucose was strongly interacted with mesoporous silica, leading to effective loading, then inverse duplicated the structure of mesoporous silica. The obtained sequence of hierarchical porous carbons possessed well-interconnected network structure and tunable wall thickness and size of network macropore. As demonstrations, the capacity of absorbed CO2 for serials of hierarchical porous carbons with three-dimensional network frameworks under room temperature was investigated. The result of CO2 adsorption isotherms indicated that the HCN pore architecture and morphologies played a key role in the CO2 capture process, specifically the size of network macropore and thickness of macroporous wall significantly affected the textural structure, the high microporous contents were benefit with improving the capacity of absorbed CO2.

A new diketopiperazine cyclo-(L-Phe-N-ethyl-L-Glu) (1), along with two known diketopiperazines cyclo-(L-Pro-L-Leu) (2) and cyclo-(L-Pro-L-Phe) (3) were isolated from the cultures of an endophytic fungus Aspergillus aculeatus F027. The structures of these compounds were elucidated based on spectroscopic data. The configurations of these compounds were determined by advanced Marfey's analysis. Antibacterial activity of the diketopiperazines against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were also evaluated.Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1677652.

Fuzi (

Through feeding 1,2-dimethylindole, two new bisindoles, chaetoindolone E and F (

The mesoporous hybrid silicas (P@BMMs) with core-shell structure were successfully synthesized via seed polymerization method using bimodal mesoporous silica materials (BMMs) as core and dual pH- and temperature-responsive poly(N-isopropylacryl-acrylamide)-co-poly(acrylic acid) (P(NIPAM-co-AA)) copolymer as shell. Meanwhile, the obtained P@BMMs were physicochemically and morphologically characterized via X-ray diffraction, N2 adsorption-desorption isotherms, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, ultraviolet visible diffused reflection spectrum, small angle X-ray scattering (SAXS), dynamic light scattering, and thermogravimetric analysis techniques. The results indicated that P(NIPAM-co-AA) was successfully coated onto the mesoporous surface of used BMMs, while the uniform mesoporous structure of obtained P@BMMs was still preserved. Using ibuprofen (IBU) as a model drug, the influence of the P(NIPAM-co-AA) shell on the release kinetics of IBU was explored, and its performances elucidated that the P@BMMs nanoparticles presented an apparent thermo/pH-responsive properties, which could be regulated via adjusting mass ratio of AA to NIPAM, and their IBU-release kinetic profiles were favorable to Korsmeyer-Peppas model. Specially, SAXS patterns were employed to evaluate the fractal evolution of P@BMMs along with releasing time, showing the decline tendency for mass fractal value from 2.89 to 2.56 during the release time of 0.25–24 h.

The location of Ag+-clusters in well-defined dielectric cavities of bi-metallic AgxNa96−x-LSX, AgxLiyNa96−x−y-LSX, and LiyAgxNa96−x−y-LSX zeolites was investigated by XRD, SEM, XPS, ESR, PESA and TG-DTG characterizations. The results showed that color of AgxM96−x-LSX zeolites changes to yellow, brown and even to black by heating up to 623 K, which may be related to the formation of Ag-Ag clusters produced by autoreduction or interaction of Ag+ ions with framework O2. During heat treatment the Ag+-clusters are migrated towards the two distinct possible cation sites (SII’ and SIII). Their ESR silent spectra indicated the diamagnetic clusters Ag3n+ formation. The ionization potentials of AgxM96−x-LSX further suggested that the electronic properties of Ag+-clusters depend strongly on space confinement and cation content. Moreover, N2 and O2 adsorption capacity, selectivity and isosteric heat show strong dependence on the location, nature, extent and order of cations exchange. Particularly, a marked decrease in isosteric heats of adsorption with an increasing N2 loading suggests heterogeneous interactions between N2 and Ag+-cluster. The strong influence of Ag+ loading and host environment on the cluster formation in correlation with structural parameters is utilized in understanding to find the most influential sites for N2 and O2 adsorption.

A kind of organic-inorganic hybrid composite with core-shell structure was successfully prepared via seed polymerization method using environmental stimuli (pH/temperature) copolymer poly(N-isopropylacryl-acrylamide)-co-poly(acrylic acid) (P(NIPAM-co-AA)) as a shell and bimodal mesoporous silica nanoparticles (BMMs) with small size of 20–50 nm as a core. The capacity of loading ibuprofen (IBU) and the subsequent release performance from resultant P(NIPAM-co-AA)@BMMs (denoted as P@BMMs) under different external conditions were investigated in detail. Meanwhile, its structural features and textural parameters were characterized using XRD, N 2 adsorption-desorption isotherms, SEM and TEM, SAXS, FT-IR, solid-state Si 29 NMR, TGA and elemental analysis techniques. The results demonstrated that P(NIPAM-co-AA) as a shell coating on the external surface of BMMs acted as temperature-pH gate valve to control release behaviors, while mesoporous BMMs as reservoir provided enough space to encapsulate IBU molecules with high loading. SAXS patterns evidently presented that P@BMMs before IBU-loading and after releasing possessed the fractal feature, suggesting their surface roughness and structural irregularities, in which the mass fractal was increased from 2.36 for BMMs to 2.41 for BMMs-MPS to 2.51 for P@BMMs, and even the transformation from the mass fractal to surface fractal for I/P@BMMs was about 2.80. In addition, three types of kinetic models (first-order, Higuchi and Korsmeyer-Peppas power law) were employed to evaluate the release profiles, indicating that the drug-release kinetic of P@BMMs was suitable to Korsmeyer-Peppas power law model with non-Fickian diffusion mechanism.

A kind of core–shell hybrid composite (P@BMMs) as a drug carrier was prepared through seed polymerization method, in which, biomodal mesoporous materials (BMMs) as core and copolymer poly(N-isopropylacryl-acrylamide)-co-poly(acrylicacid) [P(NIPAM-co-AA)] with pH- and temperature-responsive characteristics as shell. Its structural features and textural parameters were characterized using various techniques. The kinetic and thermodynamic evaluation demonstrated the existence of hydrogen bond interaction between IBU and P(NIPAM-co-AA)-coated surfaces. Meanwhile, the smart thermo/pH-responsive properties of ibuprofen (IBU) release could be regulated through adjusting coated amount of copolymer. Specially, the responsive properties of P@BMMs were traced by small-angle X-ray scattering technique, suggesting the surface roughness and structural irregularities.

Through feeding 1,2-dimethylindole, two new bisindoles, chaetoindolone E and F (1 and 2) and five known indole derivatives (3–7) were isolated from the cultures of an endophytic fungus Chaetomium sp. The structures of these compounds were elucidated based on HR-MS, NMR and single-crystal X-ray crystallography. Compounds 1 and 2 were undescribed before, compounds 3–7 were first reported from natural sources, and NMR spectrums of compounds 4 and 5 were first reported. The cytotoxity of the bisindole compounds (1–3) was also tested.

Background. Acute myocardial infarction (AMI) is regarded as an urgent clinical entity, and identification of differentially expressed genes, lncRNAs, and altered pathways shall provide new insight into the molecular mechanisms behind AMI. Materials and Methods. Microarray data was collected to identify key genes and lncRNAs involved in AMI pathogenesis. The differential expression analysis and gene set enrichment analysis (GSEA) were employed to identify the upregulated and downregulated genes and pathways in AMI. The protein-protein interaction network and protein-RNA interaction analysis were utilized to reveal key long noncoding RNAs. Results. In the present study, we utilized gene expression profiles of circulating endothelial cells (CEC) from 49 patients of AMI and 50 controls and identified a total of 552 differentially expressed genes (DEGs). Based on these DEGs, we also observed that inflammatory response-related genes and pathways were highly upregulated in AMI. Mapping the DEGs to the protein-protein interaction (PPI) network and identifying the subnetworks, we found that OMD and WDFY3 were the hub nodes of two subnetworks with the highest connectivity, which were found to be involved in circadian rhythm and organ- or tissue-specific immune response. Furthermore, 23 lncRNAs were differentially expressed between AMI and control groups. Specifically, we identified some functional lncRNAs, including XIST and its antisense RNA, TSIX, and three lncRNAs (LINC00528, LINC00936, and LINC01001), which were predicted to be interacting with TLR2 and participate in Toll-like receptor signaling pathway. In addition, we also employed the MMPC algorithm to identify six gene signatures for AMI diagnosis. Particularly, the multivariable SVM model based on the six genes has achieved a satisfying performance ( AUC = 0.97 ). Conclusion. In conclusion, we have identified key regulatory lncRNAs implicated in AMI, which not only deepens our understanding of the lncRNA-related molecular mechanism of AMI but also provides computationally predicted regulatory lncRNAs for AMI researchers.

Fuzi and ganjiang are widely used as traditional Chinese medicines (TCM) in China, Korea, Japan, and many other southeast Asian countries for treating ulcerative colitis (UC), emesis and heart failure for more than 1800 years. However, the underlying mechanism of fuzi, ganjiang and fuzi-ganjiang herb pair is still unclear. In our study, we explored the therapeutic effects of fuzi, ganjiang and fuzi-ganjiang herb pair against dextran sulfate sodium (DSS)-induced UC in mice model, along with the relevant mechanism.The contents of each marker compound in fuzi decoction (FD), ganjiang decoction (GD) and fuzi-ganjiang decoction (FGD) were determined using LC-MS/MS. During the experiment, bodyweight changes in each group were monitored every 5 days. On the day of sacrifice, colonic length, disease activity index (DAI) and spleen weight were also evaluated and histopathological examination was performed through hematoxylineosin (HE) staining. The levels of myeloperoxidase (MPO) and inflammatory cytokines in colon tissues were determined by enzyme-linked immunosorbent assay (ELISA), and then the relative mRNA productions of inflammatory mediators, such as MPO, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were measured by real-time polymerase chain reaction (PCR). Involvement of MAPK, STAT3 and NF-κB signaling pathways in the pathogenesis of UC was determined in each group using Western Blot (WB) analysis.Compared with fuzi and ganjiang single decoction, the content of the alkaloids derived from fuzi (especially the diester alkaloid with strong toxicity, hypaconitine) in fuzi-ganjiang herb pair decoction was reduced. Additionally, the 6-gingerol, which was not found in ganjiang single decoction, was retained in fuzi-ganjiang herb pair decoction. FD, GD, and FGD significantly restored the bodyweight reduction, colon shortening, DAI elevation, splenomegaly and histological score in DSS-induced UC mice. Furthermore, except for the failure of low dosage of ganjiang decoction (GD-L) on IL-17A, all FD, GD and FGD significantly inhibited the production of MPO and inflammatory cytokines, such as IFN-γ, TNF-α, IL-1β, IL-6, IL-10 and IL-17A, and suppressed the relative expression of inflammatory mediators, such as MPO, iNOS and COX-2 mRNA in colon tissues of DSS-induced mice. According to WB analysis, fuzi, ganjiang and fuzi-ganjiang combination inhibited the activation of MAPK, NF-κB and STAT3 signaling pathways.Our study demonstrated that fuzi, ganjiang and fuzi-ganjiang combination possess prominent anti-inflammatory activities against DSS-induced UC mice; the involved mechanism may be related to inhibition the activation of MAPK, NF-κB, and STAT3 signaling pathways.

A new diketopiperazine cyclo-(

The interest in the design and controllable fabrication of hollow carbon spheres (HCSs) emanates from their tremendous potential applications in adsorption, energy conversion and storage, and catalysis. However, the effective synthesis of uniform HCSs with high surface area and abundant micropores remains a challenge. In this work, HCSs with tunable microporous shells were rationally synthesized via the hard-template method using resorcinol (R) and formaldehyde (F) as a carbon precursor. HCSs with a very high surface area (1369 m2/g) and abundant micropores (0.53 cm3/g) can be obtained with the assistance of additional inorganic silanes (TEOS) simultaneously with the carbon source (RF). Interestingly, the extra-abundant micropores showed favorable adsorption for CO2, resulting in a 1.5 times increase in the CO2 adsorption capacity compared to that of normal HCSs under the same conditions. Meanwhile, these HCSs hold potential for use in the separation of gases such as CO2 and N2.

The loading properties of ibuprofen (IBU) were investigated using poly(N-isopropylacrylamide-co-acrylic acid) P(NIPAM-co-AA) copolymer nanoparticles as a carrier. Subsequently, the sensitivity of controlled release performance during changing external conditions and composition of copolymer were evaluated in detail. The results showed that the introduction of AA chains into PNIPAM framework enhanced the loading of IBU and the maximum loading capability of P(NIPAM-co-AA)-3 reached up to 7.9 wt%. The release behaviors of IBU-loaded copolymers exhibited high responsiveness to temperature and pH values. For example, P(NIPAM-co-AA)-10 exhibited a high cumulative release amount of 83.2% at 37 °C/pH 7.4, and a significant decrease in the release amount of 32.2% at 37 °C/pH 2.0. The influence of various amounts of acrylic acid (AA) and salt effect (ionic strength) on the swelling behaviors were demonstrated via dynamic light scattering method. Their microstructures and morphologies were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) techniques, which confirmed the presence of fractal structures with D m (2.65–2.87) or D s (2.0–2.33). These results further suggested that the structural evolution of P(NIPAM-co-AA) copolymer with increasing AA content had occurred from loose networks to dense aggregates with statistical self-similarity. The IBU-release mechanism was proposed, whereas the IBU diffusion contribution from P(NIPAM-co-AA) was thoroughly elucidated using three empirical equations, namely Korsmeyer–Peppas model, modified Korsmeyer–Peppas model and Higuchi model, respectively. The obtained results demonstrated that the release procedure of P(NIPAM-co-AA) was driven by typical non-Fickian diffusion mechanism in the basic medium, while in acid medium a two-stage release mechanism was observed due to their aggregation behaviors.

The pH-sensitive poly(D-A) grafted amine-functionalized bimodal mesoporous silica (D-A/BMMs) was prepared by a facile method used as a drug delivery vehicle. They exhibited superior properties such as good dispersion in aqueous medium, high drug loading efficiency, improved stability and high drug release rates. Meanwhile, its structural features and performances in a controlled delivery of ibuprofen (IBU) were systematically investigated by using XRD, N2 adsorption and desorption, SEM, TEM, FT-IR, elemental analysis and TG techniques. The results demonstrated that the obtained nanocomposite presented a flexible control over drug release by controlling the grafting amount of D-A onto the mesopores surface of aminated BMMs. The cumulative percent release of IBU from D-A/BMMs was found to be much higher at pH 7.4 than at pH 2.0. The release rate was very slow in an acidic medium but became faster in a neutral medium, owing to hydrogen bonding in an acidic medium and electrostatic repulsion between negatively charged carboxyl groups in an alkaline medium.

The novel visible light-induced carbon nitride (g-C3N4) and BiVO4 composite photocatalysts were obtained through a simple mixing-calcination method. The physical and photophysical properties of the BiVO4-g-C3N4 composites were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, high-resolution transmission electron microscopy (HRTEM), photoluminescent (PL) spectroscopy, and BET surface area measurements. Photocatalytic oxidation ability of the prepared samples was examined by studying the degradation of rhodamine B (RhB) as a target pollutant under visible-light irradiation. The composite photocatalysts exhibited an enhanced photocatalytic performance in degrading RhB. The optimal g-C3N4 content of the composite photocatalysts was determined for the photodegradation activity. The improved photocatalytic activity of the as-prepared composite photocatalyst may be attributed to the enhancement of photo-generated electron-hole separation at the interface.

Novel visible light-induced Cr-doped SrTiO3-g-C3N4 composite photocatalysts were synthesized by introducing polymeric g-C3N4. The composite photocatalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, UV-vis diffuse reflection spectroscopy, photoluminescence (PL) spectroscopy and BET surface area measurements. The photocatalytic oxidation ability of the novel composite photocatalyst was evaluated using methyl orange (MO) as a target pollutant. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO. The optimal g-C3N4 content for the photodegradation activity of the composite photocatalysts was determined. The as-prepared composite photocatalyst exhibits an improved photocatalytic activity due to enhancement of photo-generated electron-hole separation at the interface.

The interest in the design and controllable fabrication of hollow carbon spheres (HCSs) emanates from their tremendous potential applications in adsorption, energy conversion and storage, and catalysis. However, the effective synthesis of uniform HCSs with high surface area and abundant micropores remains a challenge. In this work, HCSs with tunable microporous shells were rationally synthesized via the hard-template method using resorcinol (R) and formaldehyde (F) as a carbon precursor. HCSs with a very high surface area (1369 m

A kind of core-shell hybrid composite (P@BMMs) as drug carrier was prepared via seed polymerization method, in which, bimodal mesoporous silica nanoparticles (BMMs) as core and copolymer poly(N-isopropylacryl-acrylamide) -co-poly(acrylicacid) (P(NIPAM-co-AA)) with pH- and temperature-responsive characteristics as shell. Its structural features and textural parameters were characterized using various techniques. The kinetic and thermodynamic evaluation demonstrated the existence of hydrogen-bonds interaction between IBU and P(NIPAM-co-AA)-coated surfaces. Meanwhile, the smart thermo/pH-responsive properties of IBU-release could be regulated via adjusting coated amount of copolymer. Specially, the responsive properties of P@BMMs were traced by SAXS technique, suggesting the surface roughness and structural irregularities.

ZnGaNO solid solution–C3N4 composite photocatalyst with visible light response was synthesized through polymerization of melamine in the presence of ZnGaNO solid solution. The composite photocatalyst was characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), Energy dispersed spectrometer (EDS) and BET surface area measurements. The activity of composite photocatalyst g-C3N4–ZnGaNO for photodegradation of methyl orange (MO) is higher than that of either single-phase g-C3N4 or ZnGaNO solid solution. The as-prepared composite photocatalyst exhibits an improved photocatalytic activity due to enhancement of electron–hole separations at the interface.

Porous ZnGaNO solid solution has been synthesized through a facile microwave route. The product was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), high-resolution transmission electron microscopy (HRTEM) and UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), Energy dispersed spectrometer (EDS) and N 2 -sorption. The growth process of porous ZnGaNO solid solution is investigated by XRD and SEM. The porous structure is supposed to be attributed to the release of the gaseous side products and the structural contraction through a pseudo-topological transformation. The activity of porous ZnGaNO photocatalyst for photodegradation of isopropyl alcohol (IPA) is much higher than that of ZnGaNO solid solution prepared by a solid state reaction. The as-prepared porous ZnGaNO photocatalyst exhibits an improved photocatalytic activity due to the strong gas adsorption by the porous structure and the enhancement of extended light absorption by the higher Zn content.

The assembled hexagonal vaterite plates are synthesized through a precipitation route assisted by Poly(styrene sulfonic acid) sodium salt (PSS). The as-prepared products are characterized by XRD, SEM and TEM. The assembled hexagonal vaterite plates are composed of hexagonal nanoplates in the core and hexagonal microplates at the edge. The growth process of vaterite assembled plates is investigated by XRD and SEM. It is supposed that the formation of the assembled hexagonal vaterite plates is attributed to the adsorption of ammonia, PSS and the re-crystallization of the nanoparticles. The photoluminescence (PL) property of CaCO3:Eu3+ red phosphor was also investigated through the excitation and emission spectra.

Cuprous oxides (Cu 2 O) with different morphologies were deposited on F-doped tin oxide (FTO) covered glass substrates by potentiostatic deposition. The as-deposited samples were characterized by XRD, BET surface area and SEM. The effects of Poly(styrene sulfonic acid) sodium salt (PSS) on the crystal morphologies of Cu 2 O were studied. Different crystal morphologies of Cu 2 O can be obtained by varying the concentrations of PSS in the electrolytes. The formation of dendritic microstructure in Cu 2 O film depends on the concentration of PSS in the electrolyte. Dendritic Cu 2 O crystals formed gradually with the increase of the concentration of PSS in the electrolyte from 0 to 4 g L −1 . More symmetrical Cu 2 O crystals appear when the concentration of PSS is changed from 4 to 8 g L −1 . However, the Cu 2 O nanoparticles formed instead of dendritic Cu 2 O crystals if the concentration of PSS reaches to 12 g L −1 , which is due to the slower diffusion rate of reactive species in high concentration of PSS. The as-deposited Cu 2 O thin films with different morphologies all exhibit the electrochemical glucose oxidation properties. The improved performance of glucose oxidation is achieved on the dendritic Cu 2 O film electrode. The result indicates that the dendritic microstructure is beneficial for decreasing the resistance and improving transportation and diffusion of reactants and products.

Vaterite core-shell microspheres composed of core-nanoparticles and shell-hexagonal nanoplates are synthesized by precipitation route assisted by poly(styrene sulfonic acid) sodium salt (PSS). The as-prepared products are characterized by XRD and SEM. With the addition of PSS, the crystal phase of calcium carbonate is transferred from calcite to vaterite. The growth process of vaterite microspheres is investigated by SEM. It is supposed that the core-shell structured microspheres with the nanoparticles in core and the hexagonal plates at the outer layer are attributed to the adsorption of PSS, ammonia and the re-crystallization of the nanoparticles.

III–V compound semiconductor field effect transistors (FETs) are potential candidates as solid state THz emitters and detectors due to plasma wave instability in these devices. Using a 2D hydrodynamic model, here we present the numerical studies of electron fluid instability in a FET structure. The model is implemented in a GaAs MESFET structure with a gate length of 0.2 µm as a testbed by taking into account the non-equilibrium transport and multi-valley non-parabolicity energy bands. The results show that the electronic density instability in the channel can produce stable periodic oscillations at THz frequencies. Along with stable oscillations, negative differential resistance in output characteristics is observed. The THz emission energy density increases monotonically with the drain bias. The emission frequency of electron density oscillations can be tuned by both gate and drain biases. The results suggest that III–V FETs can be a kind of versatile THz devices with good tunability on both radiative power and emission frequency.

Bimodal mesoporous silicas (BMMs) have been proved to be a good drug-loaded carrier. However, it did not provide stimuli sensitivity or controlled release performance yet. In the present work, a "smart" mesoporous silica-based pH-dependent [poly(methacrylic acid)]-silica hybrid nanoparticles (P/NN-BMMs) drug delivery system was developed and evaluated with ibuprofen (IBU) as a model drug. P/NN-BMMs were prepared by coating poly(methacrylic acid) (PMAA) onto amino-modified surface of BMMs via the "graft to" strategy. The structure and texture of resultant hybrid nanoparticles were determined with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, thermogravimetric analysis, N2 sorption isotherms, and elemental analysis. The PMAA acts as a molecular switch to achieve controlled drug release and the amount of grafted-PMAA can remarkably affect its performance. The drug-loading rate is decreased markedly with the increasing of the amount of grafted-PMAA, meanwhile, the drug-loading kinetics on P/NN-BMMs fits Korsmeyer-Peppas model. In addition, the drug-release amount from drug-loaded P/NN-BMMs is pH dependent, showing an increasing tendency with the increase of pH value.