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Current control of pathogenic bacteria at all biomaterial interfaces is poorly attuned to a broad range of disease-causing pathogens. Leading antimicrobial surface functionalization strategies with antimicrobial peptides (AMPs), defensins, have not shown their promised efficacy. One of the main problems is the lack of stability and swift clearance from the surface. Surface nanotopography bearing sharp protrusions is a non-chemical solution that is intrinsically stable and long-lasting. Previously, the geometrically ordered arrays of nanotipped spines repelled or rapidly ruptured bacteria that come into contact. The killing properties so far work on cocci and rod-like bacteria, but there is no validation of the efficacy of protrusional surfaces on pathogenic bacteria with different sizes and morphologies, thus broadening the utility of such surfaces to cover increasingly more disease entities. Here, we report a synthetic analogue of nanotipped spines with a pyramidal shape that show great effectiveness on species of bacteria with strongly contrasting shapes and sizes. To highlight this phenomenon in the field of dental applications where selective bacterial control is vital to the clinical success of biomaterial functions, we modified the poly(methyl)-methacrylate (PMMA) texture and tested it against Streptococcus mutans, Enterococcus faecalis, Porphyromonas gingivalis, and Fusobacterium nucleatum. These nanopyramids performed effectively at levels well above those of normal and roughened PMMA biomaterials for dentistry and a model material for general use in medicine and disease transmission in hospital environments.

Ion-exchanged glasses are widely used in optoelectronic devices due to its high strength and optical waveguide effects. The MgF2 films deposited on the ion-exchanged glasses and the ion-exchanged glasses bombarded by argon ions (100 eV) at 220 °C were investigated in the present work. The microstructure of MgF2 films and the structural and physico-chemical properties of the ion-exchanged glasses before and after deposition and bombardment were analyzed by grazing incident X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE-SEM), electron probe micro analysis (EPMA), micro-Raman spectroscopy and surface stress meter. It is shown that MgF2 films exhibit a polycrystalline and microcolumnar structure. The peak of potassium ions concentration distribution in the ion-exchanged glasses, accompanied by outward diffusion of potassium ions, decreases and moves from glass surface to the inner part to different degrees during deposition and bombardment. The potassium ions concentration in the region near the surface of argon ion-bombarded glasses is almost the same as the MgF2-coated glasses. Furthermore, the position and intensity of Raman bands in the subsurface region of the ion-exchanged glasses show obvious changes before and after deposition and bombardment. The values of compressive stress and depth of layer in the MgF2-coated ion-exchanged glasses and the argon ion-bombarded ion-exchanged glasses are far away lower than that of its values obtained in the ion-exchanged glasses. Overall results have shown that variations of chemical composition, Raman bands and surface compressive stress in the exchanged region indicate subsurface modification of the ion-exchanged glasses induced by deposition and bombardment, which provide useful information for the use of the ion-exchanged glasses in further.

Lithium ore (mineralized) bodies in the area A of central Yunnan Province belong to a sedimentary-type, which are controlled by stratum. The studied ore (mineralized) body mainly occurs in the Middle Permian Liangshan Formation. This work described the morphology, structures, main ore types and geochemical characteristics of this ore body in detail, and discussed the ore-forming material source, occurrence state of lithium and the formation mechanism of lithium ores to clarify the prospecting marks. In the further exploration, comprehensive evaluation of the lithium resources of known bauxite ore bodies in central Yunnan Province should be strengthened, and the exploration of hidden lithium ore bodies should be intensified in order to discover more large and super-large lithium orebodies, which will fill the gap of the national demand for lithium resources, and promote the national defense construction and new energy industry development.

Background The CRISPR/dCas9 system is a powerful tool to activate the transcription of target genes in eukaryotic or prokaryotic cells, but lacks assays in complex conditions, such as the biosynthesis of secondary metabolites. Results In this study, to improve the transcription of the heterologously expressed biosynthetic genes for the production of epothilones, we established the CRISPR/dCas9-mediated activation technique in Myxococcus xanthus and analyzed some key factors involving in the CRISPR/dCas9 activation. We firstly optimized the cas9 codon to fit the M. xanthus cells, mutated the gene to inactivate the nuclease activity, and constructed the dCas9-activator system in an epothilone producer. We compared the improvement efficiency of different sgRNAs on the production of epothilones and the expression of the biosynthetic genes. We also compared the improvement effects of different activator proteins, the ω and α subunits of RNA polymerase, and the sigma factors σ54 and CarQ. By using a copper-inducible promoter, we determined that higher expressions of dCas9-activator improved the activation effects. Conclusions Our results showed that the CRISPR/dCas-mediated transcription activation is a simple and broadly applicable technique to improve the transcriptional efficiency for the production of secondary metabolites in microorganisms. This is the first time to construct the CRISPR/dCas9 activation system in myxobacteria and the first time to assay the CRISPR/dCas9 activations for the biosynthesis of microbial secondary metabolites. Electronic supplementary material The online version of this article (10.1186/s12934-018-0867-1) contains supplementary material, which is available to authorized users.

We used force-field based grand-canonical Monte Carlo simulation method and density functional theory to study adsorption characteristics of carbon dioxide (CO2) molecules in a metal-organic framework (MOF) compound, [Zn(bdc)(dpds)]n. The studied MOF include a metal ion (Zn(II)), an anion organic linker (dianion of benzene dicarboxylicacid, bdc2−) and a neutral organic linker (4,4′-dipyridyldisulfide, dpds). Results from calculated adsorption isotherms and enthalpies of adsorption agree with the experimental data. The interactions between the adsorbed CO2 and the organic linkers were examined in simulations. Calculated results show available absorption sites are surrounded by two dpds ligands in which an S-S bond as an N-N′ spacer connect two pyridines. In contrast, the bdc2− ligand does not give a significant contribution to the substantial adsorption amount even though it contains the carboxylate group that provides available bonding site to CO2.

We have successfully synthesized a multilayer-structured composite based on a combination of polydopamine (PDA)-coated silver nanoparticles (Ag@PDA) and silver nanowires (AgNWs@PDA) using a flexible and rapid method. We incorporated the structure into polyvinyl alcohol (PVA) polymer to enhance thermal conductivity and dielectric properties of nanocomposite films. Compared with Ag@PDA/PVA and AgNWs@PDA/PVA films, the use of multilayer-structure facilitated increased thermal conductivity and reduced permittivity of the nanocomposite film. The maximum thermal conductivity of composite with 10 wt% filler loading was increased to 3.63 W/mK, which is an enhancement by nearly 20 times compared with the use of neat PVA matrix. The relative permittivity and dielectric loss were about 6.65 and 0.024 at 1 MHz, respectively. We discussed the underlying mechanisms in an effort to optimize the structure for polymer matrix nanocomposites.

One of the most important aspects in the field of dentistry is adhesion. Adhesion can be enhanced through different mechanisms, most commonly by chemical and mechanical modifications of dental material surfaces. One example of chemical adhesion utilizes primers or bonding agents containing coupling agents. Universal primers which are (mainly organophosphate-based monomers) and silane coupling agents are the most effective and most widely used for unifying dissimilar materials. Other than improving adhesion, Silanes have many other applications in dentistry. They have been found also to enhance the mechanical properties of materials either by adhesion or by becoming a constituent of dental materials itself. Universal primers, on the other hand, are utilized in bonding between different dental materials such as ceramics, metals, alloys, as well as to resin composites. Unfortunately, these primers, coupling agents, and bonding agents have, in general, poor hydrolytic stability. They are susceptible to humid oral environment, which invariably render them potentially unstable in the humid oral environment as saliva is always present. Improving their hydrolytic stability should therefore result in stronger adhesion for dental materials and dental prosthesis with a better clinical survival rate.

The aim was to evaluate in vitro the feasibility of using three silane coupling agents/blends: (I) 1.0 vol % 3-acryloxypropyltrimethoxysilane (ACPS), (II) a novel silane system: 1.0 vol % 3-acryloxypropyl trimethoxysilane + 0.5 vol % bis-1,2-(triethoxysilyl)-ethane (ACPS + BTSE), and (III) a novel silane system: 1.0 vol % 3-acryloxypropyl trimethoxysilane + 0.5 vol % bis[3-(trimethoxysilyl)propyl]amine (ACPS + BTMA), as adhesion promoters on the repair of dental silver amalgam with a resin composite with respect to various artificial ageing conditions. Two hundred and forty flowable composite resin stubs were bonded to freshly prepared dental silver amalgam discs. The discs were silica-coated and silanized with the 3 silanes. Another 20 resin stubs were bonded to the amalgam surface without any silica-coating or treated with silica-coating only. Then, the specimens were randomly distributed into 8 sub-groups for initial (control), thermal cycling (1000, 3000 and 6000) and DI water storage (1 day, 1 week, 1 month and 3 months). Shear bond strength (SBS) test was measured using a universal testing machine with a 1 mm/min cross-head speed. Failure modes were classified and SEM images were obtained. Two-way ANOVA was used to detect statistical differences. The initial SBS of the control groups were (Mean/SD) 20.2 ± 3.3 MPa for ACPS only, 16.6 ± 3.9 MPa for ACPS + BTMA, and 19.5 ± 3.3 MPa for ACPS + BTSE. A decreasing trend of SBS was observed by using the current artificial ageing methods, and ACPS and ACPS + BTSE produced statistically higher bond strengths compared to ACPS + BTMA under thermal cycling (p

An effective resolving agent, (D)-dibenzoyl tartaric acid (2b), was screened to yield direct resolution of (S)- ethyl nipecotate (1) with high optical purity and yield. Molecular recognition was studied by 1H NMR, IR, DSC and single crystal diffraction of the pair of diastereomeric salts. The less-soluble salt formed a supra molecular structure by enantio differentiating self-assembly.

The optically pure ethyl nipecotate is an important drug intermediates. It was used for a variety of synthesis of APIs and pharmaceutical intermediates. In this paper we launched a study of the split of ethyl nipecotate. An efficient resolution of (±)-nipecotic acid has been achieved by the fractional crystallization with good yield and high enatio. The compound (S)-ethyl-1-(2-thiopheneacetyl)-3-piperidine-carboxylate is an investigational immune potentiating agent targeting direct stimulation of immune cells, useful for the prevention of infectious diseases in livestock.

Monomers based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. A multistep synthesis of the electron-poor 5,6-bis (heptyloxy) benzo [[1,2,thiadiazole are presented. The new deficient acceptor has good solubility in organic solvents to permit an appropriate coating process.

Heterocyclic oligomer based on BBT bearing solubilizing side chains have been synthesized in high yields over six steps from readily available starting materials. This approach offers a much milder, shorter, and more efficient route to BBT derivatives than current methods. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions.

Heterocyclic monomer based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over three steps from readily available starting materials. The alkyl side chain in the 4-position of both thiophene rings gives the material mononer a good solubility.

Heterocyclic monomers based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. The new dificient acceptor has good solubility in organic aolvents to permit an appropriate coating process. Two soluble donor-acceptor π-conjugated oligomers comprising electron-rich thiophenes the electron-deficient EDOBT have been carefully investigated.

A synthetic approach to synthesize 4,8-Dibromobenzo-[1,2-c;4,5-c’] bis[1,2,5]thiadiazole from a common precursor 2,1,3-Benzothiadiazole is reported. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions.

Heterocyclic electron-poor monomer [1,2,5]thiadiazolo[3,4-c]pyridine have been synthesized in high yields over five steps from readily available starting materials. The new deficient acceptor has good solubility in organic solvents so as to permit an appropriate coating process.

Heterocyclic monomers based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. A multistep synthesis of the electron-poor 6, 7-dihydro-1, 4-dioxino-[2, 3-f][2,1,3]-benzothiadiazole are presented. The new dificient acceptor has good solubility in organic aolvents to permit an appropriate coating process.

A mide, simple and efficient synthetic procedure for the preparation of 2,7-dibromo-2′,3′,6′,7′-tetra(2-methylbutyloxy)spirobifluorene and key intermediates, tetra(2-methlbutyloxy)biphenyl ，2-bromo-4,5,3′,4′-tetra(2-methylbutyloxy)biphenyl, 2,7-Dibromo-2′,6,3′,7′--tetra(2-methylbutyloxy)biphenyl-9-Fluorenol, has been developed. The procedure described herein offers several advantages, including high product yields, easy purification, and large scale production. Ether protected 2,7-dibromo-9,9′-spirobifluorene has good solubility in organic aolvents to permit an appropriate coating process, ability to achieve various colors so as to make full color display elements possible.

Purpose: To isolate and characterize primary fetus retinal microvascular endothelial cells (RMECs) in order to facilitate the study of their properties in vitro. Methods: Human RMECs were isolated from abortive fetuses whose gestational ages were between 20 and 28 weeks by mechanical morcel and trypsin-collagenase digestion, plated on fibronectin-coated wells and purified gradually in high-selective condition. The RMECs were characterized for expression and localization of endothelial cell markers by indirect immunocytochemical staining of von Willebrand factor (vWF) and CD34, the distribution of cell markers was observed by confocal immunofluorescence microscope. The ability of these cells to form capillary-like networks was assessed subsequently. Cobalt dichloride (CoCl2) was used to simulate hypoxia in the culture condition and Western blot was used to detect the alternation of VEGF protein level under normoxia and hypoxia. Results: Isolation of fetus RMECs has been very difficult and primary culture of these special premature RMECs has not been previously reported due to many reasons. Here we established a simple and convenient method for the primary culture of fetus human RMECs. Our results show that delicate RMECs could be obtained readily and grow very fast, and the purity of RMECs was up to 95% demonstrated by specific staining for vWF in the cytoplasm. Our research also indicates that nearly 100% of cells could express CD34. The cells were successfully passaged and maintained in culture for 5–7 passages without a significant loss in expression of endothelia cell markers. The fetus RMECs formed capillary-like networks on the Matrigel well. Expression of VEGF protein increased significantly under hypoxia. Conclusions: Pure fetus RMECs could be obtained rapidly and easily by our method.Fetus RMECs have some specific properties. Hypoxia could induce expression of VEGF. Cell properties related with age of the donors should be considered while studying in vitro, especially in some age-specific diseases such as retinopathy of prematurity and diabetic retinopathy.

We explored a novel 3D sandwich structure of fillers in the polymer matrix to enhance thermal conductivity. A variety of fillers in the polymer matrix play a significant role in the physical properties of the composite. Fillers containing particle and line structures are popular, and enhance the thermal and electrical conductivities. Therefore, filler-based matrix network improves conductivity. We propose a sandwich structure consisting of hybrid graphite nanosheets (two dimensions), and silver nanowires (AgNWs) (one dimension), to create a 3D sandwich structure of polyimide matrix with improved thermal conductivity. Surface treatment of graphite and silver nanowires were conducted to reduce the dielectric constant of the composite. We designed the filler of 20 wt% resulting in a high thermal conductivity of 3.21 W m−1 K−1 with 15% C@SiO2 and 5% AgNWs@SiO2 filler loading. The novel combination and structure markedly enhanced the thermal conductivity of the composite.

Yeast cells were utilized as templates to synthesize ZnWO 4 hollow microspheres photo-catalyst in this paper. Moreover, the main influencing factors in the photocatalytic degradation of low concentration RhB dye wastewater had been studied by using as-obtained hollow ZnWO 4 photo-catalyst. The results of experiments indicate that pH, concentration of RhB dye and dosage of catalyst had significant influence on the degradation efficiency of RhB dye wastewater. The degradation rate reached 87.5% under the condition when amount of ZnWO 4 is 2g/L, pH 6, and the concentration of RhB at 0.5×10−5 mol/L.

We have identified compound physical-chemical properties and structural criteria required to facilitate the adsorption of hydroxypyridines, quinolines, and pyrimidines onto aluminum(III), iron(III), and titanium(IV) oxides. We achieved this by measuring the adsorption behavior of a number of structurally related compounds, each with a nearly isolated variation in molecular structure, and systematically evaluating the effect of structural change on the nature and extent of adsorption. We find that the adsorption at the metal oxide-water interface is significant only when the oxo-hydroxy (keto-enol) tautomeric equilibrium in aqueous solution favors the hydroxy tautomer. Lack of adsorption of the oxo tautomer can be attributed to the absence of favorable electrostatic interactions between the compound and the surface, the absence of ligand groups capable of surface complexation, and the presence of strong intermolecular hydrogen bonding between ligand groups (carbonyl and amide) and water molecules. We find that adsorption of hydroxy tautomers with ortho-substituted cyclic N and -OH groups (such as trichloropyridinol) likely occurs via nonspecific electrostatic interactions, while non-ortho-substituted hydroxy tautomers (such as 8-hydroxyquinoline) and compounds such as (2-hydroxy-methylpyridine) likely adsorb via surface complexation. This study demonstrates that for compounds classified as tautomeric heterocycles it is imperative to accurately represent the predominant tautomer in aqueous solution so that the appropriate physical-chemical properties and reactivities are utilized in the evaluation of environmental fate.

Objective: The study was to observe the effect of polymer-PS (Curosurf)mixtures on acute lung injury rats with E.coli. Methods: Adult rats given 3ml/kg 3x109CFU/ml E.coli by tracheal, were mechanically ventilated after infection for 24~36h. Fifteen minutes later, the animals with ALI (PaO2 < 20.kPa) were randomly divided into six treatment groups by transtrachea instillation (1) NS group (2) PS group (3) PS+NS group (4) PS+ PEG group (5) PS+ Dextran group (6) PS+ HA group. The blood gas analysis were measured in the pre-or post-treatment during 180 min. At the end, MIP-2 in the right lung lavage fluid were performed. Result: At 180 min post-treatment, PaO2 of all PS or PS-polymer treatment groups increased compared with pre-treatment, but they were less than normal control group (p< 0.01), PaO2 of PS, PS+ Dextran, PS+HA group were singnificantly more than that of the NS group (p< 0.01 or 0.05) respectively. MIP-2 of lung lavage fluid in all treatment groups were higher than that of normal group (p< 0.01 or 0.05). MIP-2 of PS, PS+PEG, PS+ Dextran, PS+ HA group were less than that of NS group (p< 0.01) respectively except PS+NS group. Conclusions: The data suggest that PS, PS+Dextran and PS+HA improved oxygenation function in ventilated rats with ALI induced by E.Coli. and the PS-polymer mixtures seemed more effective in inhibiting MIP-2 than PS in the same dose. Further preclinical studies are required.