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Capturing circulating tumor cells (CTCs) from peripheral blood for subsequent analyses has shown potential in precision medicine for cancer patients. Broad as the prospect is, there are still some challenges that hamper its clinical applications. One of the challenges is to maintain the viability of the captured cells during the capturing and releasing processes. Herein, we have described a composite material that could encapsulate a magnetic Fe3O4 core in a MIL-100 shell (MMs), which could respond to pH changes and modify the anti-EpCAM antibody (anti-EpCAM-MMs) on the surface of MIL-100. After the anti-EpCAM-MMs captured the cells, there was no need for additional conditions but with the acidic environment during the cell culture process, MIL-100 could realize automatic degradation, leading to cell self-release. This self-release model could not only improve the cell viability, but could also reduce the steps of the release process and save human and material resources simultaneously. In addition, we combined clinical patients' case diagnosis with the DNA sequencing and next generation of RNA sequencing technologies in the hope of precision medicine for patients in the future.

In this study, eight types of materials including nanoparticles (Cu and CaCO3), metallic ions (Ca2+ and Cu2+), and amino acid substances (serine, tyrosine, sericin amino acid, and fibroin amino acid) were used as additives in silkworm diets to obtain in-situ modified silk fiber composites. The results indicate that tyrosine and fibroin amino acids significantly increase potassium content in silk fibers and induce the transformation of α-helices and random coils to β-sheet structures, resulting in higher crystallinities and better mechanical properties. However, the other additives-modified silk fibers show a decrease in β-sheet contents and a slight increase or even decrease in tensile strengths. This finding provides a green and effective approach to produce mechanically enhanced silk fibers with high crystallinity on a large scale. Moreover, the modification mechanisms of these additives were discussed in this study, which could offer new insights into the design and regulation of modified fibers or composites with desirable properties and functions.

The determination of alendronate (ALE) in biofluids using a low-cost instrument is potentially useful in preclinical pharmacokinetic studies. This study developed and validated a high-performance liquid chromatography with ultraviolet method for ALE determination in rat plasma using precolumn derivatization with phenyl isothiocyanate (PITC). Inhibiting compounds in the samples were first eliminated using solid-phase extraction. ALE in the sample was subsequently allowed to react with PITC to form a phenylthiocarbamoyl derivative for further analysis. The assay was linear within the concentration range of 0.29–25.0 µg/mL. The precision and accuracy were less than 3.9% and 98.0 ± 3.9%, respectively. The limits of detection and quantification were 0.08 and 0.20 µg/mL, respectively. The method was successfully used to evaluate the pharmacokinetic parameters of ALE in rats following a single oral administration (30.0 mg/kg). The results show that the peak plasma ALE concentration is 0.69 ± 0.18 µg/mL. ...

The estuarine turbidity maximum (ETM) under strong tidal dynamics (during spring tides) was investigated along the Deepwater Navigation Channel (DNC) in the North Passage (NP) of the Changjiang River Estuary (CRE) in wet and dry seasons of 2016, 2017 and 2018. The observed water current, salinity, stratification and suspended sediment concentration (SSC) were illustrated and analyzed. Results show that the SSC was lower in wet seasons than dry seasons in 2016 and 2017 because of the weak influence of typhoons before observations in wet seasons. On the contrary, the SSC was higher in the wet season than the dry season in 2018 because of the strong influence of typhoons in the wet season. Our observations challenged the common perspective that SSC in the NP is higher in wet seasons than dry seasons, because the magnitudes of SSC were found to be easily influenced by strong winds before observations. The along-channel distribution of high SSC was determined by the location of salt wedge, and consequently, the ETM was further upstream in dry seasons than wet seasons. The observed SSC was more concentrated in lower water layers in wet seasons (&ldquo, exponential&rdquo, profile) than dry seasons (&ldquo, linear&rdquo, profile). This seasonal difference of vertical SSC was related to the flocculation setting velocity influenced by temperature rather than the weak stratification during spring tides. Moreover, on the basis of the net water/sediment transport and flux splitting, large river discharge and a low-SSC condition could reduce siltation in the middle DNC. The former vanished the convergence of water transport, and the latter reduced landward tidal pumping sediment transport. Sediment trapping and siltation in the dry seasons occurred in the seaward segment of the upper reach because of the decrease in the river discharge.

Epithelial tumor cells may display different collective invasion behaviors, forming an unjammed flow like a fluid or a jammed deformation like a solid depending on such factors as cell–cell adhesion, cell–substrate adhesion, or the density and shapes of the cells. We investigate the relation between the collective motility and the shapes of human cancer cells under heat stress. The collective dynamics of MGC-803 cells in a confluent monolayer subjected to heat stress at 48 °C for 10 min were observed and analyzed using the long-term live imaging technique. We found that the normal cell motions slow down with increasing cell density and cell–cell adhesion, accompanied by a decrease in the average aspect ratio of the cell shapes and substrate-to-cell traction. Heat stress can speed up cellular motions while almost maintaining the same cell density and cell–cell adhesion and also increases the cell shape index and the traction force exerted by the cells on the substrate. An approximately linear relation is revealed between the collective migration velocity and the shape index of the heated cells. This work helps explain the collective motility of cancer cells and provides inspiration for regulating cell motion with factors such as temperature.

Research on erosion behavior of sediments usually treats sand and mud separately. However, natural soil often occurs as a sand–mud mixture. An expression for cohesive forces in sand–mud mix...

Heterologous expression of the type III polyketide synthase (PKS) gene vioA in marine-derived Streptomyces youssoufiensis OUC6819 led to production of six violapyrones (VLPs), including four novel compounds VLPs Q–T (1–4) and two known compounds VLPs B and I (5 and 6). The structures of 1–4 were elucidated by a combination of spectroscopic analyses, including HR-ESIMS and 1D and 2D NMR data, demonstrating that 1–4 are novel VLPs which are methylated at 4-OH with their corresponding non-methylated counterparts to be VLP A, 5 and 6 and VLP C, respectively. Anti-influenza A [H1N1 (A/Virginia/ATCC1/2009) and H3N2 (A/Aichi/2/1968)] virus activity of compounds 1–6 as well as VLPs A and C were then evaluated using ribavirin as a positive control (IC50 = 66.7 and 99.6 μM). The results revealed that these VLPs showed considerable anti-H1N1 and anti-H3N2 activities with IC50 values of 30.6–132.4 μM and 45.3–150.0 μM, respectively. Notably, all the methylated VLPs displayed better anti-virus activity than their non-methylated counterparts, among which compound 3 (VLP S) exhibited the best activities. Interestingly, methylation at 4-OH has negative effect on the anti-MRSA (methicillin-resistant Staphylococcus aureus) activity instead, with methylated VLPs displaying decreased (2) or abolished (3 and 4) activities in comparison with each of their non-methylated counterparts.

Background Type III polyketide synthases (PKSs) are simple homodimer ketosynthases that distribute across plants, fungi, and bacteria, catalyzing formation of pyrone- and resorcinol-types aromatic polyketides with various bioactivities. The broad substrate promiscuity displayed by type III PKSs makes them wonderful candidates for expanding chemical diversity of polyketides. Results Violapyrone B (VLP B, 10), an α-pyrone compound produced by deepsea-derived Streptomyces somaliensis SCSIO ZH66, is encoded by a type III PKS VioA. We overexpressed VioA in three different hosts, including Streptomyces coelicolor M1146, Streptomyces sanyensis FMA as well as the native producer S. somaliensis SCSIO ZH66, leading to accumulation of different violapyrone compounds. Among them, S. coelicolor M1146 served as the host producing the most abundant violapyrones, from which five new (2–4, 7 and 12) and nine known (1, 5, 6, 8–11, 13 and 14) compounds were identified. Anti-influenza A (H1N1) virus activity of these compounds was then evaluated using ribavirin as a positive control (IC50 = 112.9 μM), revealing that compounds 11–14 showed considerable activity with IC50 values of 112.7, 26.9, 106.7 and 28.8 μM, respectively, which are significantly improved as compared to that of VLP B (10) (IC50 > 200 μM). The productions of 10 and 13 were increased by adding P450 inhibitor metyrapone. In addition, site-directed mutagenesis experiment led to demonstration of the residue S242 to be essential for the activity of VioA. Conclusions Biological background of the expression hosts is an important factor impacting on the encoding products of type III PKSs. By using S. coelicolor M1146 as cell factory, we were able to generate fourteen VLPs compounds. Anti-H1N1 activity assay suggested that the lipophilic nature of the alkyl chains of VLPs plays an important role for the activity, providing valuable guidance for further structural optimization of VLPs. Electronic supplementary material The online version of this article (10.1186/s12934-018-0908-9) contains supplementary material, which is available to authorized users.

Filtration of circulating tumor cells (CTCs) in peripheral blood is of proven importance for early cancer diagnosis, treatment monitoring, metastasis diagnosis, and prognostic evaluation. However, currently available strategies for enriching CTCs, such as magnetic activated cell sorting (MACS), face serious problems with purity due to nonspecific interactions between beads and leukocytes in the process of capturing. In the present study, the tumor-targeting molecule folic acid (FA) and magnetic nanoparticles (MNPs) were coated on the surface of red blood cells (RBCs) by hydrophobic interaction and chemical conjugation, respectively. The resulting engineered RBCs rapidly adhered to CTCs and the obtained CTC-RBC conjugates were isolated in a magnetic field. After treatment with RBC lysis buffer and centrifugation, CTCs were released and captured. The duration of the entire process was less than three hours. Cell counting showed that the capture efficiency was above 90% and the purity of the obtained CTCs was higher than 75%. The performance of the proposed method exceeded that of MACS® beads (80% for capture efficiency and 20% for purity) under the same conditions. The obtained CTCs could be successfully re-cultured and proliferated in vitro. Our engineered RBCs have provided a novel method for enriching rare cells in the physiological environment.

Recently, red blood cell (RBC) membrane-coated nanoparticles have attracted much attention because of their excellent immune escapability; meanwhile, gold nanocages (AuNs) have been extensively used for cancer therapy due to their photothermal effect and drug delivery capability. The combination of the RBC membrane coating and AuNs may provide an effective approach for targeted cancer therapy. However, few reports have shown the utilization of combining these two technologies. Here, we design erythrocyte membrane-coated gold nanocages for targeted photothermal and chemical cancer therapy. First, anti-EpCam antibodies were used to modify the RBC membranes to target 4T1 cancer cells. Second, the antitumor drug paclitaxel (PTX) was encapsulated into AuNs. Then, the AuNs were coated with the modified RBC membranes. These new nanoparticles were termed EpCam-RPAuNs. We characterized the capability of the EpCam-RPAuNs for selective tumor targeting via exposure to near-infrared irradiation. The experimental results demonstrate that EpCam-RPAuNs can effectively generate hyperthermia and precisely deliver the antitumor drug PTX to targeted cells. We also validated the biocompatibility of the EpCam-RAuNs in vitro. By combining the molecularly modified targeting RBC membrane and AuNs, our approach provides a new way to design biomimetic nanoparticles to enhance the surface functionality of nanoparticles. We believe that EpCam-RPAuNs can be potentially applied for cancer diagnoses and therapies.

Additional file 1: Table S1. Plasmids and strains used in this study. Table S2. Primer pairs used in this study. Table S3. Homologous locus of vioAB in different Streptomyces genomes. Figure S1. Relative yields for compounds 1â 14 in different strains. Figure S2. Spectral data of 1. Figure S3. Spectral data of 2. Figure S4. Spectral data of 3. Figure S5. Spectral data of 4. Figure S6. Spectral data of 5. Figure S7. Spectral data of 6. Figure S8. Spectral data of 7. Figure S9. Spectral data of 8. Figure S10. Spectral data of 9. Figure S11. Spectral data of 10. Figure S12. Spectral data of 11. Figure S13. Spectral data of 12. Figure S14. Spectral data of 13. Figure S15. Spectral data of 14. Figure S16. Multiple-sequence alignments of VioA with selected type III PKSs. Figure S17. Site-directed mutagenesis study of VioA.

On the basis of the social constructivist theory of emotion, we examined the relationship between employees' emotional creativity and innovative performance in the Chinese business environment, as well as the mediating or moderating roles of intrinsic motivation and supervisors' support for employee creativity in this relationship. Participants were 546 supervisor–subordinate dyads employed at 18 enterprises in the areas of Changsha, Guangzhou, Nanjing, Hangzhou, and Shanghai in China. We performed factor analysis, correlation analysis, and regression analysis of the collected data, and found that employees' emotional creativity had significant effects on their innovative performance, and that their intrinsic motivation played a mediating role in the relationship between emotional creativity and innovative performance. We also found that the supervisors' support for employee creativity positively moderated the relationship between emotional creativity and intrinsic motivation. In addition, the supervisors' support for creativity acted as a mediated moderator of the relationship between employees' emotional creativity and innovative performance.

At 13:46 on March 11, 2011 (Beijing time), an earthquake of Mw=9.0 occurred in Japan. By comparing the tsunami data from Guanhekou marine station with other tsunami wave observation gathered from southeast coastal area of China, it was evident that, only in Guanhekou, the position of the maximum wave height appeared in the middle part rather than in the front of the tsunami wave train. A numerical model of tsunami propagation based on 2-D nonlinear shallow water equations was built to study the impact range and main causes of the special tsunami waveform discovered in Jiangsu coastal area. The results showed that nearly three-quarters of the Jiangsu coastal area, mainly comprised the part north of the radial sand ridges, reached its maximum tsunami wave height in the middle part of the wave train. The main cause of the special waveform was the special underwater topography condition of the Yellow Sea and the East China Sea area, which influenced the tsunami propagation and waveform significantly. Although land boundary reflection brought an effect on the position of the maximum wave height to a certain extent, as the limits of the incident waveform and distances between the observation points and shore, it was not the dominant influence factor of the special waveform. Coriolis force’s impact on the tsunami waves was so weak that it was not the main cause for the special phenomenon in Jiangsu coastal area. The study reminds us that the most destructive wave might not appear in the first one in tsunami wave train.

Swertia mussotii (Gentianaceae) is a traditional Chinese medicinal plant grown in the Qinghai-Tibet Plateau. Three fractions from S. mussotii extract, named SWF50, SWF 70 and SWF100, were screened for in vitro anti-proliferative activity on two gastric cancer cell lines, MGC-803 and BGC-823 cells using MTT assay. Our results demonstrated that SMF70 showed an anti-proliferative effect in MGC-803 cells and SMF100 showed an anti-proliferative effect in BGC-823 cells in vitro. Moreover, both two fractions induced apoptosis via depolymerization of cytoskeletal filaments, increased cytoplasmic levels of ROS and Ca2+ and disrupted mitochondrial transmembrane potential. In addition, flow cytometry analysis indicated that both two fractions could induce cell apoptosis and arrest the cell cycle at S phase. Our results indicate that SMF70 induces apoptosis of MGC-803 cells and SMF100 induces apoptosis of BGC-823 cells via a mitochondrial-dependent pathway. Meanwhile, we also investigated antitumor effect of SMF70 in vivo, and exhibited effective tumor growth inhibition. Our findings demonstrate that S. mussotii extracts could be a potential new alternative therapeutic agent gastric cancer.

Deep-sea microbes are a rich source of novel bioactive compounds, which have developed unique genetic systems as well as biosynthetic pathways compared with those of terrestrial microbes in order to survive in extreme living environment. However, a large variety of deepsea-microbial secondary metabolic pathways remain ‘cryptic’ under the normal laboratory conditions. Manipulation of global regulators is one of the effective approaches for triggering the production of cryptic secondary metabolites. In this study, by combination of various chromatographic purification process, we obtained somalimycin (1), a new antimycin-type depsipeptide, with an unusual substitution of 3-amidosalicylate instead of conserved 3-formamidosalicylate moiety, along with two known (2 and 3) analogues from the ΔwblAso mutant strain of deepsea-derived Streptomyces somaliensis SCSIO ZH66. The structures of 1−3 were elucidated on the basis of extensive spectroscopic analyses including LC-MS and NMR. In the evaluation of potent anti-inflammatory activity, compound 2 exhibited strong inhibitory activity on the IL-5 production in OVA-stimulated splenocytes with IC50 value of 0.57 μM, while 1 and 3 displayed mild effect (> 10 μM), which might be attributed to their different side-chain substitutions. Moreover, compounds 1−3 showed very weak cytotoxicity against human umbilical vein endothelial cells (HUVEC) with LD50 values of 62.6, 34.6 and 192.9 μM, respectively, which were far over their IL-5 inhibitory activity. These results indicated that these compounds have good potential for further use in anti-inflammatory drug development.

The chemical investigation of ethanolic extract from Swertia mussotii Franch. has resulted in the isolation of 11 compounds which were identified as Orcinol-β-D-glucoside (1), Shamimin (2), Mangiferin (3), Decussatin (4), Bellidifolin (5), Desmethylbellidifolin (6), Protocatechuic acid (7), 1,7-Dihydroxy-3,8-dimethoxyxanthone (8), 1,8-Dihydroxy-3,5-dimethoxyxanthone (9), 1-Hydroxy-3,5-dimethoxyxanthone (10), Telephioidin (11). The chemical structures of these compounds were identified by a combination of spectroscopic analysis and a comparison with those reported in literature. Among them, compounds 1, 2, 7 and 11 were isolated from the genus Swertia for the first time. Moreover, the chemotaxonomic significance of these compounds was summarised. The chemotaxonomic study suggests that there is a close chemotaxonomic relationship between S. mussotii and other species of Swertia, such as S. punicea, S. macrosperma, S. japonica, S. phragmitiphylla, S. chirayita, S. cordata and S. binchuanensis, with presence of compounds 3~6, 8~10. The xanthones and their glycosides may sever as important chemotaxonomic markers of Swertia genus.

In recent year, the transmission of spatial information present the characteristic of amount users, broad coverage area, multiple service, and convenient access, which make research focus for SIN (spatial information network) users in the area of intelligent TT&C (telemetry, tracking and command) and management. Based on the deep analysis of TDRSS (Tracking and Data Relay Satellite System) application modes, an assumption of TT&C and management for SIN based on the TDRS SMA (S-band Multiple Access) system is proposed. Analysis is mainly focused on the panoramic beam, system composition and user access, also the protocol architecture, communication workflow, and TDRS terminal are original designed. Compared to traditional operational mode, the proposed assumption could realize ubiquitous perception, random access, on-line management, and satellite-ground cooperation for users’ application. Relevant result could be referenced in the study of TT&C and management for SIN.

This paper reports the impacts of direct feeding silkworms with different nanoparticles (Cu, Fe, and TiO2) on the morphology, structures, and mechanical properties of the resulting silk fiber (SF). The contents of the Cu nanoparticles were 38 times higher in the posterior silk glands and only 2-3 times higher in the SF and in the middle silk glands compared with the controlled groups. Significant changes of the surface morphology, structures, and diameter of the Cu nanoparticle fed SF have been observed, which are attributed to a slight SF protein reconstruction or conformational change in the mixture of silk fibroin and sericin in the silk glands. The resulting Cu-containing SF exhibits good tensile strength of 360MPa and reaches a strain of 38%, which are 89% and 36% higher than those of the natural SF. This study offers a new green strategy for the easy modification to achieve robust composite SF.

The phase composition and microstructure formation mechanism of in-situ Cu-Fe micro-composites were investigated. The microstructures of longitudinal and transverse sections were analyzed by light microscopy and scanning electron microscopy. The phase analysis was executed by X-ray diffraction. The common microstructure characteristic of Cu-XFe (X = 11, 14 and 17) alloys was that the second phase α-Fe dendrites were uniformly distributed in the Cu matrix. The disorderly distributed Fe dendrites of Cu-14Fe alloy underwent initial inhomogeneous deformation and then were gradually changed into the directionally arranged Fe fibers of in-situ Cu-14Fe micro-composite in the longitudinal section, and were gradually transformed into the irregular V-shaped Fe fibers in the transverse section. The initial inhomogeneous deformation and the irregular V-shaped Fe fibers in the transverse section are closely related to the formation of texture.

Hydrodynamics and the estuarine turbidity maximum (ETM) were investigated along the Deepwater Navigation Channel (DNC) in the North Passage (NP) of the Changjiang River Estuary (CRE) during spring tides in March (dry season) and July (wet season) in 2016. The along-channel water current, salinity, and suspended sediment concentration (SSC) were measured and compared with a study undertaken in 2012. Results show that the magnitude of SSC in the dry season was significantly larger than that in the wet season in 2016, which was contrary to the results obtained in 2012 and the commonly held understanding that SSC is much higher in wet seasons than dry seasons in this region. Despite the abnormal magnitude of the SSC, the spatial distribution agreed with that of the 2012 observations, and corresponded to the salinity distribution. By analysing the bottom sediment flux and sediment transport over a flood-ebb tidal cycle, the immediate cause of the abnormal SSC magnitudes was found. In the dry season, the resuspension fluxes were more than doubled and tidal pumping terms were significantly larger than of those in the wet season, thus indicating that the resuspension effect was much stronger and able to bring more sediment into the water. Although the strong resuspension effect in the dry season was partly due to a slightly higher tidal dynamic, it was mainly due to the availability of sufficient sediment for resuspension, as induced by the strong cold-air front several days previous. On the contrary, the weak resuspension effect under a similar tidal dynamic in the wet season, was associated with insufficient sediment availability as a result of the limited influence of the typhoon in 2016. In addition, the quantity of sediments available for resuspension influenced the mobile suspension (MS) events of the ETM. Local resuspension and along-channel advection were both important in SSC variation processes and the effect of along-channel advection was more distinct when there was insufficient sediments for resuspension.

Epidermal growth factor receptor (EGFR) that has been over-expressed in many different types of cancers has become logical targets for both diagnosis and therapy. Herein, we report an electrochemical peptide-based biosensor for the detection of EGFR, in which ferrocene moiety modified peptide ligands that are specific to EGFR were immobilized on gold electrode through Au–S interaction. Upon the binding of peptide ligands with EGFR, complex formation changes occurred on the electrode surface, which resulted in current increase. The amplitude of the current increase displayed a linear relationship with logarithm of the EGFR concentrations in the range of 1.0 × 10−6–1.0 × 10−10 g L−1, with a detection limit of 3.7 × 10−11 g L−1. The proposed method has been applied for determination of EGFR in diluted human serum samples with satisfied results.

Since the 21st century, Spatial laser communication has made a breakthrough development. Europe, the United States, Japan and other space powers have carried out the test of spatial laser communication technology on-orbit, and put forward a series of plans. In 2011, China made the first technology demonstration of satellite-ground laser communication carried by HY-2 satellite. Nowadays, in order to improve the transmission rate of spatial network, the topic of spatial laser communication network is becoming a research hotspot at home and abroad. This thesis, from the basic problem of spatial laser communication network to solve, analyzes the main difference between spatial network and ground network, which draws forth the key technology of spatial laser communication backbone network, and systematically introduces our research on aggregation, addressing, architecture of spatial network. From the perspective of technology development status and trends, the thesis proposes the development route of spatial laser communication network in stages. So as to provide reference about the development of spatial laser communication network in China.

Deepsea microbes are a rich source of novel bioactive compounds, which have developed unique genetic systems as well as biosynthetic pathways compared with those of terrestrial microbes in order to survive in extreme living environment. However, a large variety of deepsea-microbial secondary metabolic pathways remain “cryptic” under the normal laboratory conditions. Manipulation of global regulators is one of the effective approaches for triggering the production of cryptic secondary metabolites. In this study, by combination of various chromatographic purification process, we obtained somalimycin (1), a new antimycin-type depsipeptide, with an unusual substitution of 3-aminosalicylate instead of conserved 3-formamidosalicylate moiety, along with two known (2 and 3) analogs from the ΔwblAso mutant strain of deepsea-derived Streptomyces somaliensis SCSIO ZH66. The structures of 1–3 were elucidated on the basis of extensive spectroscopic analyses including LC-MS and NMR. In the evaluation of potent anti-inflammatory activity, compound 2 exhibited strong inhibitory activity on the IL-5 production in ovalbumin-stimulated splenocytes with IC50 value of 0.57 μM, while 1 and 3 displayed mild effect (>10 μM), which might be attributed to their different side-chain substitutions. Moreover, compounds 1–3 showed very weak cytotoxicity against human umbilical vein endothelial cells with LD50 values of 62.6, 34.6, and 192.9 μM, respectively, which were far over their IL-5 inhibitory activity. These results indicated that these compounds have good potential for further use in anti-inflammatory drug development.

The wblAso gene functions as a global regulatory gene in a negative manner in deepsea-derived Streptomyces somaliensis SCSIO ZH66. A new dioic acid (1) as well as two known butenolides (2 and 3) were isolated from the ΔwblAso mutant strain of S. somaliensis SCSIO ZH66. The structure of 1 was elucidated by a combination of spectroscopic analyses, including MS and NMR techniques. In the cell growth inhibitory evaluation, compound 3 exhibited moderate activity against the human hepatic carcinoma cell line (Huh7.5) with an IC50 value of 19.4 μg/mL, while compounds 1 and 2 showed null activity up to 100 μg/mL.

Additional file 1: Table S1. Anti-MRSA activities of violapyrones (VLPs 1â 5). Table S2. Bacteria and plasmids used in this study. Table S3. The primer pairs used for cosmid library screening. Table S4. The primer pairs used for PCR-targeted mutagenesis. Table S5. The primer pairs used for PCR confirmation of the mutants. Table S6. The primer pairs used for qPCR analysis. Figure S1. Inactivation of wblA so . Figure S2. Spectral data of VLP B, 1. Figure S3. Inactivation of pksIII-1. Figure S4. Inactivation of vioA. Figure S5. Inactivation of vioB. Figure S6. Inactivation of orf1. Figure S7. Inactivation of orf(-1-2). Figure S8. Spectral data of VLP J, 3. Figure S9. Spectral data of VLP A, 2. Figure S10. Spectral data of VLP C, 4. Figure S11. Spectral data of VLP H, 5. Figure S12. Phenotypes of the S. somaliensis SCSIO ZH66 strains.

Face recognition has become an important issue in many applications such as security systems, credit card verification and criminal identification. The recently proposed shape descriptor, Pyramid Histogram of Oriented Gradients (PHOG) features, counts occurrences of gradient orientation in localized portions of an image and has been proved as an efficient tool for providing spatial distribution of edges. In this paper, we proposed to use pyramid histogram of oriented gradients (PHOG) as the features extracted for face recognition. The obtained feature vectors are fed up into Support Vector Machine (SVM) classifier for classification. Experiments carried out on UMIST Face Database databases that both frontal head images and rotated head images are investigated. The experimental results show this approach can be used to automatically identify the faces more effective.

Two C-rich DNA strands are employed to fabricate the intermolecular i-switch: strand 1 with thiol at the 5′-terminus immobilized on the gold electrode through the thiol–Au interaction, and ferrocene (Fc)-labeled strand 2 that hybridizes with strand 1 to form an i-switch nanostructure. In neutral or basic aqueous solution, the i-switch is present in the form of an extended duplex that makes Fc far away from the electrode; a weak faradaic current is obtained, so-called “OFF” state. While in the slight acidic condition, an obvious signal is detected from Fc which approaches the electrode due to the formation of the i-motif, so‐called “ON” state. The faradaic current has a linear relationship with the pH value in the range of 5.8–8.0. Keywords: i-Motif, i-Switch, pH, Electrochemistry, DNA hybridization

In this study, using round paper tubes (PTs) and rectangular cardboard boxes (CBs) as external constraints to control the size of the cocooning space, we fabricated a series of modified silkworm cocoons (PT cocoons and CB cocoons). Their microstructures, morphologies, compositions, and mechanical properties were characterized and compared with normal silkworm cocoons. These two kinds of modified silkworm cocoons exhibit dense and homogeneous layer structures. Tensile test results indicate that above a size limit of cocooning space, their tensile strengths, Young&rsquo, s moduli, and strain energy densities increase with the decrease in cocooning space. Especially in comparison with the normal cocoons, the tensile strength and Young&rsquo, s modulus of the PT-14 cocoon increase by 44% and 100%, respectively. Meanwhile, PT cocoons and CB cocoons, except PT-12, also possess better peeling resistance than normal cocoons. Owing to the dense structure and low porosity, the modified cocoons form robust fiber networks that result in high strength and toughness. This study provides a green and efficient method to fabricate mechanically enhanced silkworm cocoons with special shapes and dense layer structures. The method can be easily subjected to further modification processes and has potential applications in the production of high-performance green cocoon composites and biomimetic materials.

Zn 0.95− x Co 0.05 Cu x O (ZCCO, where x = 0, 0.005, 0.01 and 0.015) thin films were deposited on Si (1 0 0) substrates by pulsed laser deposition technique. Crystal structures, surface morphologies, chemical compositions, bonding states and chemical valences of the corresponding elements for ZCCO films were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and X-ray photoelectron spectroscopy (XPS). XRD and FESEM results indicate that crystallite sizes of the highly (0 0 2)-oriented ZCCO films slightly decrease with increasing Cu content. When the Cu content increases from 0 to 0.015, Zn 2 p 3/2 , Co 2 p , Cu 2 p 3/2 and O 1 s peaks of the ZCCO film shift towards higher or lower binding energy regions, and the reasons for these chemical shifts are investigated by fitting the corresponding XPS narrow-scan spectra. Both in-plane and out-of-plane magnetization-magnetic field hysteresis loops of the ZCCO films reveal that all the films have room temperature ferromagnetisms (RTFMs). The conceivable origin of the RTFM is ascribed to the combined effects of the local structural disorder resulted from (Co 2+ , Cu 2+ , Cu 1+ )-cations which substitute Zn 2+ ions in the ZnO matrices, ferromagnetic coupling between coupled dopant atoms caused by Co 2+ (3 d 7 4 s 0 ) and Cu 2+ (3 d 9 4 s 0 ) spin states, and exchange interactions between the unpaired electron spins originating from lattice defects induced by Cu doping in the Zn 0.95 Co 0.05 O matrices.

Ba0.9Sr0.1TiO3 (BST) thin films were deposited on fused quartz and Pt/TiN/Si3N4/Si substrates by radio frequency magnetron sputtering technique. Microstructure and chemical bonding states of the BST films annealed at 700 °C were characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, glancing angle X-ray diffraction and Raman spectrum. Optical constants including refractive indices, extinction coefficients and bandgap energies of the as-deposited BST film and the BST films annealed at 650, 700 and 750 °C, respectively, were determined from transmittance spectra by envelope method and Tauc relation. Dielectric constant and remnant polarization for the BST films increase with increasing annealing temperature. Leakage current density-applied voltage (J–V) data indicate that the dominant conduction mechanism for all the BST capacitors is the interface-controlled Schottky emission under the conditions of 14 V

Radio frequency magnetron sputtered Ba"0"."6"5Sr"0"."3"5TiO"3 (BST) thin films were etched in CF"4/Ar/O"2 plasma by magnetically enhanced reactive ion etching technique. The etching characteristics of BST films were characterized in terms of microstructure and electrical properties. Atomic force microscopy and X-ray diffraction results indicate that the microstructure of the etched BST film is degraded because of the rugged surface and lowered intensities of BST (100), (110), (111) and (200) peaks compared to the unetched counterparts. Dielectric constant and dielectric dissipation of the unetched, etched and postannealed-after-etched BST film capacitors are 419, 346, 371, 0.018, 0.039 and 0.031 at 100kHz, respectively. The corresponding dielectric tunability, figure of merit and remnant polarization are 19.57%, 11.56%, 17.25%, 10.87, 2.96, 5.56, [email protected]/cm^2, 2.32 and [email protected]/cm^2 at 25V, respectively. The leakage current density of 1.75x10^-^4 A/cm^2 at 15V for the etched BST capacitor is over two orders of magnitude higher than 1.28x10^-^6 A/cm^2 for the unetched capacitor, while leakage current density of the postannealed-after-etched capacitor decreases slightly. It means that the electrical properties of the etched BST film are deteriorated due to the CF"4/Ar/O"2 plasma-induced damage. Furthermore, the damage is alleviated, and the degraded microstructure and electrical properties are partially recovered after the etched BST film is postannealed at 923K for 20min under a flowing O"2 ambience.

The novel 2D snowflake-like ZnO structures have been self-assembly synthesized on SiO2/Si substrate coated with Pt strips by thermal evaporation of Zn power. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy measurements showed that the snowflake-like ZnO possesses the perfect six-fold symmetric single-crystalline wurtzite structure. The room-temperature photoluminescence spectrum revealed a strong ultraviolet emission band at 382 nm. The possible growth process was also discussed. It was found that the deposition of thin layer of Pt strips is important for the formation of 2D snowflake-like ZnO structures.

A modified sol–gel method was used to fabricate (Pb 0.25 Ba x Sr 0.75− x )TiO 3 (PBST) thin films with x = 0.05,0.1,0.15 and 0.2 on Pt/TiO 2 /SiO 2 /Si substrate. The structure, surface morphology, dielectric and tunable properties of PBST thin films were investigated as a function of barium content ( x ). X-ray diffraction and scanning electron microscopy analysis showed that we could get pure PBST perovskite phase and relative fine density thin films with smooth surface. It was found that the crystal lattice constant, grain size, room temperature dielectric constant, dielectric loss and tunability of Ba solutionizing PST thin films increased with the increase in Ba content. For (Pb 0.25 Ba 0.2 Sr 0.55 )TiO 3 thin film, it had the highest dielectric constant of 1390 and the largest tunability of 80.6%. The figure of merit parameter reached a maximal value of 28.9 corresponding to the (Pb 0.25 Ba 0.05 Sr 0.7 )TiO 3 thin film, whose dielectric constant, dielectric loss and tunability measured at 1 MHz were 627, 0.024 and 69.4%, respectively.

Highly transparent conductive Dy 2 O 3 doped zinc oxide (ZnO) 1– x (Dy 2 O 3 ) x nanocrystalline thin films with x from 0.5% to 5% have been deposited on glass substrate by pulsed laser deposition technique. The structural, electrical and optical properties of Dy 2 O 3 doped thin films were investigated as a function of the x value. The experimental results show that the Dy concentration in Dy-doped ZnO thin films has a strong influence on the material properties especially electrical properties. The resistivity decreased to a minimum value of 5.02 × 10 −4 Ω cm with x increasing from 0.5% to 1.0%, then significantly increased with the further increasing of x value. On the contrary, the optical direct band gap of the (ZnO) 1– x (Dy 2 O 3 ) x films first increased, then decreased with x increasing. The average transmission of Dy 2 O 3 doped zinc oxide films in the visible range is above 90%.

In this paper, in-situ electrospinning method was presented to directly fabricate semiconductor (Ag2S or Cu2S) nanostructures on the outer surfaces of polyacrylonitrile (PAN) nanofibers. PAN/metallic salt composite fibers were electrospun firstly as precursors, after UV irradiation photoreduction and the treatment of H2S gas, Ag2S or Cu2S nanostructures can be obtained on the outer surface of PAN nanofibers. The interactions between the polymer and metallic ions are believed to be the main factor in determining the position of metallic ions based on the electrospun nanofibers. Transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) are used to characterize the products.

In this work, composite nanostructures of BiFeO 3 (BFO) and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymers were fabricated using porous anodic aluminum oxide (AAO) templates by sol–gel and vacuum infiltration methods. Scanning electron microscope (SEM) and high-resolution transmission electron microscopy (HRTEM) were employed to investigate the morphology of composite nanostructures. It was found that a double-layer nanostructure with inner P(VDF-TrFE) copolymers for high insulating property and outer BFO nanotubes for mechanical supporting. The leakage current density of BFO/P(VDF-TrFE) composite nanostructures is four orders of magnitude lower than that of BFO under ±8 MV/m. It is suggested that the facile approach has great potential in multiferroic devices.

Nowadays, H.264/AVC is an effective standard for video coding. However, with the growing demand for higher compression ratio of moving pictures in various applications, it's quite desirable for new methods which adapt to high definition videos in the flexible environments. In order to improve the efficiency of the intra prediction for videos, especially for the high definition ones, we propose a new algorithm to establish intra prediction, which processes pixels based on line with adaptively detecting the texture changes. Experimental results demonstrate that, compared with H.264/AVC intra method, the proposed algorithm has achieved much better prediction, and reduced the complexity in the meantime.

In this study, an electrochemical impedance biosensor for cyanobacterial toxin microcystin-LR (MC-LR) detection has been developed. MC-LR aptamers were immobilized on the gold electrode through Au-S interaction, in the presence of target (MC-LR); the binding of MC-LR and aptamers probe led to a complex formation change on the electrode surface and resulted in the impedance decreasing. The decrease rate had a linear relationship with logarithm of the MC-LR concentration in the range of 1.0 × 10(-7)-5.0 × 10(-11)mol/L, with a detection limit of 1.8 × 10(-11)mol/L. The sensor has good selectivity and stability, it has been applied to detect MC-LR in three kinds of real water samples with satisfying results.

Tag antenna can make RFID tags be read at a distance and do not require a line of sight between tag and reader. This paper describes design and optimization aspects of antenna coil of tag for RFID system in High Frequency (HF) band. An equivalent circuit of tag is established and a new detailed design method is demonstrated. An experimental formula with high efficiency is used to calculate the inductance of the coil. It also presents a method for inductor optimization for tag antenna design which can set different objective functions and constraints for corresponding purpose in different conditions easily. Through the calculation of Matlab, the result of this method is feasible and globally convergent.

Organocatalytic direct anti-selective Mannich reactions of O-TBS-hydroxyacetone with various N-tosylimines derived from aromatic aldehydes in the presence of L-threonine-derived catalyst afforded 1,2-amino alcohols in good yields and with enantioselectivities of 99% in almost all cases.

The paper is devoted to a study of methods for characterizing and diagnosing the beam quality of high energy laser. It begins with a review of the rationality and usability of the parameters that have been used for characterizing laser beam quality. Considering the specific characteristics of high energy laser, we suggest characterizing the beam quality of high energy laser with diffraction limit multiple β-factor and encircled energy ratio BQ . Then the selection of the referential (or ideal) beam for β-factor is discussed in detail and the far-field diffraction intensity distributions and divergent angles of various referential beams have been calculated and compared. The results show that among all of referential beams with the same diffraction area or external aperture size, the circular solid homogenous beam has the smallest far-field divergent angle, thus choosing such a beam as the ideal beam would be the most reasonable and strongly proposed. Finally, techniques for diagnosing the beam quality of high energy laser are presented.

A DNAzyme-based electrochemical biosensor for magnesium ion (Mg2+) has been developed. Firstly, the Mg2+-dependent DNAzyme with thiol at the 5′-terminus is immobilized on a gold electrode through thiol–Au interaction. Then the substrate strand with ferrocene (Fc) at the 5′-terminus is attached to the gold electrode via hybridization with DNAzyme. In the absence of Mg2+, this sensor shows an obvious faradaic current from Fc. In the presence of Mg2+, the Fc-labeled substrate strand is cleaved into two pieces by catalytic action of DNAzyme and moves away from the electrode surface, which reduces the faradaic current. The current change provides quantitative measurement of Mg2+. The linear response range for the proposed biosensor is 0.2–5.0 mmol L−1, and the detection limit is 0.05 mmol L−1. Other divalent metals present do not interfere with Mg2+ detection. The sensor was applied to detect Mg2+ in serum with satisfactory results.