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β-cyclodextrin butenate was synthesized by using N, N'-Carbonyldiimidazole (CDI) activating reagent and 4-Dimethylaminopyridine (DMAP) as catalyst. The best preparation condition of β-CD butenate was described as below: reaction temperature was 25°C, concentration of 2-butenoic acid was 450 mmol/L, concentration of DMAP was 12.5 mmol/L and reaction time was 20 minutes and at this condition the yield of β-CD butenate was 0.83 mmol/g. According to the results of FT-IR spectrum, NMR spectroscopy and HPLC-QTof-mass spectrum of β-CD butenate, there were four types β-CD butenate synthesized, which were β-CD-2-butenoic acid monoester, β-CD-2-butenoic acid diester, β-CD-2-butenoic acid triester and β-CD-2-butenoic acid tetraester, respectively. [ABSTRACT FROM AUTHOR]

We designed and prepared a supramolecular assembly-induced emission enhancement supramolecular polymer (PyP5⊂S 2 NH 2) via rational combination host−guest and π−π stacking interactions between pyrene-functionalized pillar[5]arene host (PyP5) and the bis(dialkylammonium salt)-based BB type guest (S 2 NH 2). With the increasing concentration of S 2 NH 2 and PyP5 , the structures of PyP5⊂S 2 NH 2 transformed from linear to cross-linked networks. Moreover, PyP5⊂S 2 NH 2 can be sensitive to multiple stimuli, including temperature, redox, UV-light, pH, solvent polarity, organometallic compound, and competitive guest. This work paves the way to develop fluorescent supramolecular polymers with multi-stimuli-responsive properties via facilely supramolecular approaches. [Display omitted] [ABSTRACT FROM AUTHOR]

The β-cyclodextrin-acrylamide (CDM-AM) copolymer was prepared from acrylamide and β-CD maleate (CDM) using 60Co γ-ray irradiation method. The optimized preparation conditions for the CDM-AM copolymer are as follows: CDM:AM mass ratio of 1:1; irradiation dose of 4 kGy; and using 20 mL of DMF water solution. The yield rate of CDM-AM was 75% in grams using these synthetic conditions. The effects of the CDM-AM copolymer on the solubility and fungicidal activity of natamycin (NM) and carbendazim (MBC) were investigated. The stability constant of NM·CDM-AM and MBC·CDM-AM complexes at 303 K were of 13,446.06 M−1 and 2595.3 M−1, respectively. The complexes were characterized using phase solubility diagrams, NMR spectra and FT-IR spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone. [ABSTRACT FROM AUTHOR]

In this work, a novel supramolecular π-gel has been constructed using a naphthalimide functionalized pillar[5]arene-based gelator (MP5). The gelator MP5 simultaneously contains a naphthalimide moiety as the π…π interaction site as well as a fluorophore. Interestingly, the MP5-based supramolecular π-gel (MP5-G) exhibits strong aggregation-induced emission (AIE). MP5-G exhibited good thermal-responsiveness, acid and base-responsiveness and cation and amino acid-responsiveness. Meanwhile, this supramolecular π-gel also shows selective fluorescence sensing for Fe3+via cation–π interactions with high selectivity and sensitivity, and the detection limit of MP5-G for Fe3+ is 6.06 × 10−8 M. Even more meaningfully, MP5-G could remove Fe3+ from water solution with excellent recyclability and ingestion capacity, and the Fe3+ removal rate can reach up to 99.8%. Furthermore, the Fe3+ coordinated supramolecular gel, MP5-FeG, shows selective fluorescence “turn-on” sensing for l-Cys. The detection limit of MP5-FeG for l-Cys is 1.0 × 10−8 M. Simultaneously, thin films based on these supramolecular gels were prepared, which were confirmed to be convenient test kits for detecting Fe3+ and l-Cys. In addition, these supramolecular π-gels could be used as sensitive ion sensors, sensitive logic gates and fluorescent display materials. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC), a major global cause of diarrhea, initiates the pathogenic process via fimbriae-mediated attachment to the small intestinal epithelium. A common prototypic ETEC fimbria, colonization factor antigen I (CFA/I), consists of a tip-localized minor adhesive subunit CfaE and the stalk-forming major subunit CfaB, both of which are necessary for fimbrial assembly. To elucidate the structure of CFA/I at atomic resolution, three recombinant proteins were generated consisting of fusions of the minor and major subunits (CfaEB) and of two (CfaBB) and three (CfaBBB) repeats of the major subunit. Crystals of CfaEB diffracted X-rays to 2.1 Å resolution and displayed the symmetry of space group P21. CfaBB exhibited a crystal diffraction limit of 2.3 Å resolution and had the symmetry of space group P21212. CfaBBB crystallized in the monoclinic space group C2 and diffracted X-rays to 2.3 Å resolution. These structures were determined using the molecular-replacement method. [ABSTRACT FROM AUTHOR]

Enteric virus concentration in large-volume water samples is crucial for detection and essential for assessing water safety. Certain dissolution and suspension components can affect the enrichment process. In this study, tangential flow ultrafiltration (TFUF) was used as an enrichment method for recovering enteric virus in water samples. Interestingly, the bacteriophage MS2 recovery in reclaimed water and the reclaimed water without particles were higher than that in ultrapure water. The simulated reclaimed water experiments showed that humic acid (HA) (92.16% ± 4.32%) and tryptophan (Try) (81.50 ± 7.71%) enhanced MS2 recovery, while the presence of kaolin (Kaolin) inhibited MS2 recovery with an efficiency of 63.13% ± 11.17%. Furthermore, Atomic force microscopy (AFM) revealed that the MS2-HA cluster and the MS2-Try cluster had larger roughness values on the membrane surface, making it difficult to be eluted, whereas MS2-Kaolin cluster had compact surfaces making it difficult to be eluted. Additionally, the MS2-HA cluster is bound to the membrane by single hydrogen bond with S O, whereas both the MS2-Try cluster and the MS2-Kaolin cluster are bound to the membrane by two hydrogen bonds, making eluting MS2 challenging. These findings have potential implications for validating standardized methods for virus enrichment in water samples. [Display omitted] • Suspended particles and DOMs can affect virus recovery by ultrafiltration. • HA and Try enhanced the recovery rate of virus, while Kaolin inhibited it. • MS2-HA and MS2-Try had looser surface, while MS2-Kaolin had compact surface. • The single hydrogen bond binding MS2-HA to the membrane makes viral elution easier. [ABSTRACT FROM AUTHOR]

Abstract: The ATP-binding cassette protein ABCG2 is a member of a broad family of ABC transporters with potential clinical importance as a mediator of multidrug resistance. We carried out a homology and knowledge-based, and mutationally improved molecular modeling study to establish a much needed structural framework for the protein, which could serve as guidance for further genetic, biochemical, and structural analyses. Based on homology with known structures of both full-length and nucleotide-binding domains (NBD) of ABC transporters and structural knowledge of integral membrane proteins, an initial model of ABCG2 was established. Subsequent refinement to conform to the lipophilic index distributions in the transmembrane domain (TMD) and to the results of site-directed mutagenesis experiments led to an improved model. The complete ABCG2 model consists of two identical subunits facing each other in a closed conformation. The dimeric interface in the nucleotide-binding domain (NBD) involves a characteristic nucleotide sandwich and the interface in the TMD consists of the TM helices 1–3 of one subunit and the helices 5 and 6 of the other. The interface between the NBD and the TMD is bridged by the conserved structural motif between TM2 and TM3, the intracellular domain 1 (ICD1), and the terminal β-strand (S6) of the central β-sheet in the NBD. The apparent flexibility of the ICD1 may play a role in transmitting conformational changes from the NBD to the TMD or from the TMD to the NBD. [Copyright &y& Elsevier]

Abstract: An asphalt–salt mixture (ASM), which once caused a fire and explosion in a reprocessing plant, was prepared by imitating the real bituminization process of waste on a lab scale to evaluate its actual thermal hazards. Heat flux reaction calorimeters were used to measure the release of heat for the simulated ASM at a constant heating rate and at a constant temperature, respectively. Experimental results show that the reaction in the ASM below about 250°C is a slightly exothermic interface reaction between the asphalt and the salt particles contained in the asphalt, and that the heat release rate increases sharply above about 250°C due to melting of the salt particles. The reaction rates were formulated on the basis of an assumed reaction model, and the kinetic parameters were determined. Using the model with the kinetic parameters, temperature changes with time and drum-radius axes for the ASM-filled drum were numerically simulated assuming a one-dimensional infinite cylinder system, where the drum was being cooled at an ambient temperature of 50°C. The minimum filling temperature, at which the runaway reaction (MFTRR) can occur for the simulated ASM in the drum is about 194°C. Furthermore, a very good linear correlation exists between this MFTRR and the initial radius of salt particles formed in the bituminization product. The critical filling temperature to the runaway reaction is about 162°C for the asphalt–salt mixture, containing zero-size salt particles, filled in the same drum at an ambient temperature of 50°C. Thus, the runaway reaction will never occur in the drum filled with the asphalt–salt mixture under the conditions of the filling temperature below 162°C and a constant ambient temperature of 50°C. As a consequence, the ASM explosion occurred in the reprocessing plant likely was due to a slightly exothermically reaction and self heating. [Copyright &y& Elsevier]

l-2-Haloacid dehalogenase catalyzes the hydrolytic dehalogenation of l-2-haloalkanoic acids to produce the corresponding d-2-hydroxyalkanoic acids. Asp10 of l-2-haloacid dehalogenase from Pseudomonas sp. YL nucleophilically attacks the α-carbon atom of the substrate to form an ester intermediate, which is subsequently hydrolyzed by an activated water molecule. We previously showed that the replacement of Thr14, Arg41, Ser118, Lys151, Tyr157, Ser175, Asn177, and Asp180 causes significant loss in the enzyme activity, indicating the involvement of these residues in catalysis. In the present study, we tried to determine which process these residues are involved in by monitoring the formation of the ester intermediate by measuring the molecular masses of the mutant enzymes using ionspray mass spectrometry. When the wild-type enzyme and the T14A, S118D, K151R, Y157F, S175A, and N177D mutant enzymes were mixed with the substrate, the ester intermediate was immediately produced. In contrast, the R41K, D180N, and D180A mutants formed the intermediate much more slowly than the wild-type enzyme, indicating that Arg41 and Asp180 participate in the formation of the ester intermediate. This study presents a new method to analyze the roles of amino acid residues in catalysis. [Copyright &y& Elsevier]

Cerasus dielsiana (Rosaceae) is one of the most characteristic wild flowering cherry species endemic to subtropical China, with high conservation value from ornamental, economic, and ecological perspectives. To verify its spatial genetic structure and phylogeographic history, evaluation of nuclear (ITS) sequence variation in 203 individuals from 25 wild populations across its natural distribution ranges was conducted. High levels of ribotypes and nuclear diversity (Hd = 0.879 ± 0.012, π = 3.56 ± 0.16) were detected at the species level. Spatial analysis of molecular variation (SAMOVA), median-joining network and phylogenetic Neighbour-joining tree assigned the populations into four genetically distinct groups. Meanwhile, high levels of genetic differentiation among populations and strong phylogeographic patterns (Nst = 0.837 > Gst = 0.585; P < 0.05) were revealed based on the analysis of molecular variance (AMOVA). Results of neutrality tests, mismatch distribution analyses, Mantel test, barrier analyses, together with ecological niche modelling (ENM) simulation and BEAST analysis suggest a long-term demographic history (95% HPD: 3.64–8.83 Mya) of C. dielsiana, and at least three potential in situ glacial refugia as well as recent demographic expansion in eastern region have been detected. Collectively, we highlight that the combined effect of natural selection and random genetic drift under complex topography and palaeoclimatic oscillations since the Last Glacial Maximum (LGM) in subtropical China might have been the main driver to the species' allopatric differentiation. Scientific conservation and sustainable utilization for wild C. dielsiana germplasm resources were subsequently proposed. [ABSTRACT FROM AUTHOR]

Three undescribed lignan glycosides, echiunines E -G (1 – 3), as well as eight known compounds (4 – 11) were isolated from Fritillaria verticillata Willd. Among them, compounds 1 – 3 were a series of lignan glycosides reported for the first time from genus Fritillaria. Their structures were elucidated by analyses of extensive spectroscopic data and comparison of the NMR data with those reported previously, the absolute configuration of compounds were further confirmed by calculated ECD method. The NO release inhibitory effects of compounds were evaluated in LPS-activated RAW264.7 macrophages. Compounds 7 – 8 showed inhibitory acitivities in a dose-dependent manner. [Display omitted] [ABSTRACT FROM AUTHOR]

In transportation cyber-physical-systems (T-CPS), vehicle-to-vehicle (V2V) communications play an important role in the coordination between individual vehicles as well as between vehicles and the roadside infrastructures, and engine cylinder pressure is significant for engine diagnosis on-line and torque control within the information exchange process under V2V communications. However, the parametric uncertainties caused from measurement noise in T-CPS lead to the dynamic performance deterioration of the engine cylinder pressure estimation. Considering the high accuracy requirement under V2V communications, a high gain observer based on the engine dynamic model is designed to improve the accuracy of pressure estimation. Then, the analyses about convergence, converge speed and stability of the corresponding error model are conducted using the Laplace and Lyapunov method. Finally, results from combination of Simulink with GT-Power based numerical experiments and comparisons demonstrate the effectiveness of the proposed approach with respect to robustness and accuracy. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Chemical investigation of Fritillaria verticillata Willd. led to the isolation of eight novel isosteroidal alkaloids (1—4, 6, 9—11) and four known alkaloids (5, 7—8, 12), including three unprecedented cis‐fused D/E (13α, 17α) cevanine alkaloids (1—3), one rarely cis‐fused E/F (22α) cevanine alkaloid (6), and one uncommon 5β‐jervine‐type isosteroidal alkaloid featuring a cis‐fused A/B ring moiety (11). In order to establish the structures of 1, the calculated NMR with DP4+ evaluation was applied from the plausible structure candidates. The characteristic proton signals for distinguishing D/E conjunction of cevanine alkaloids were summarized. In addition, some proton and carbon signals α to nitrogen in 6 and 7 are unobservable due to the 14N nuclear quadrupolar relaxation, based on the NMR experiments in different solvents, calculated NMR method and X‐ray technology, their structures were determined. The NMR characteristics of cevanine alkaloids to distinguish orientation of long‐pair on nitrogen atom with β‐hydroxyl at C‐20 were also concluded. The anti‐inflammatory effects of compounds 1 and 4 were evaluated in LPS‐activated RAW 264.7 macrophages. Compound 4 decreased LPS‐induced releases of IL‐1β and IL‐17α in RAW264.7 cells in a dose‐dependent manner. Further mechanistic study revealed that 4 suppressed the phosphorylation of IκBα and p65 subunit to regulate the NF‐κB signaling pathway. [ABSTRACT FROM AUTHOR]

Cytochrome bc1 is an integral membrane protein complex essential for cellular respiration and photosynthesis; it couples electron transfer from quinol to cytochrome c to proton translocation across the membrane. Specific bc1 inhibitors have not only played crucial roles in elucidating the mechanism of bc1 function but have also provided leads for the development of novel antibiotics. Crystal structures of bovine bc1 in complex with the specific Qo site inhibitors azoxystrobin, MOAS, myxothiazol, stigmatellin and 5-undecyl-6-hydroxy-4,7-dioxobenzothiazole were determined. Interactions, conformational changes and possible mechanisms of resistance, specific to each inhibitor, were defined. Residues and secondary structure elements that are capable of discriminating different classes of Qo site inhibitors were identified for the cytochrome b subunit. Directions in the displacement of the cd1 helix of cytochrome b subunit in response to various Qo site inhibitors were correlated to the binary conformational switch of the extrinsic domain of the iron–sulfur protein subunit. The new structural information, together with structures previously determined, provide a basis that, combined with biophysical and mutational data, suggest a modification to the existing classification of bc1 inhibitors. bc1 inhibitors are grouped into three classes: class P inhibitors bind to the Qo site, class N inhibitors bind to the Qi site and the class PN inhibitors target both sites. Class P contains two subgroups, Pm and Pf, that are distinct by their ability to induce mobile or fixed conformation of iron–sulfur protein. [Copyright &y& Elsevier]

Cerasus serrulata (Rosaceae) is an important flowering cherry resource which is valuable for developing new cultivars of flowering cherries. It is broadly distributed and possesses abundant variations. In this study, phylogeographic analysis was conducted to reveal the evolutionary history to better understand the genetic diversity and genetic structure of C. serrulata so as to provide more accurate molecular insights into better conservation and utilization of the germplasm resources. A total of 327 individuals from 18 wild populations were collected. Three chloroplast DNA (cpDNA) fragments (matK, trnD‐E, and trnS‐G) and the nuclear internal transcribed spacer (ITS) were utilized. The results showed a high genetic diversity at both species level and population level of C. serrulata. High genetic differentiation and the existence of the phylogeographic structure were detected. No significant expansion events were discovered. Two geographic lineages were inferred. One was confined to the Qinling Mountains and the Taihang Mountains. The other was from the Wuling Mountains to the Jiangnan Hilly Regions and then went northeast to the coast of Asia. In addition, some taxonomic treatments of the C. serrulata complex are discussed and reconsidered. Conservation and utilization strategies of wild C. serrulata germplasm resources were recommended. [ABSTRACT FROM AUTHOR]

Abstract A novel supramolecular organic framework gel (PQPA) has been constructed by a novel bilateral 8-hydroxyquinoline modified pillar[5]arene host (P5Q) and a bilateral bromohexyl functionalized pillar[5]arene guest (P5C6). Interestingly, the gel PQPA shows special selective and ultrasensitive sensing property for Fe3+. The limit of lowest detection (LOD) of gel PQPA for Fe3+ is 0.102 nM. Meanwhile, by adding Fe3+ into the gel PQPA , a no fluorescence Fe3+ coordinated metallogel (PQPA-Fe) could be constructed. Due to the competitive coordination of F−, fluorescent "turn-on" ultrasensitive response of the Fe3+ coordinated metallogel (PQPA-Fe) for F− is achieved. The limit of lowest detection of the Fe3+ coordinated metallogel (PQPA-Fe) for F− is 9.79 nM. In addition, the xerogel of the supramolecular organic framework gel (PQPA) is capable for removing Fe3+ in a lower concentration aqueous solution at an adsorption rate of 99.9%. More importantly, the supramolecular organic framework gel (PQPA) could be used to detect Fe3+ in the Yellow River Water samples. The supramolecular organic framework gel (PQPA) and Fe3+ coordinated metallogel (PQPA-Fe) could act as ultrasensitive reversible fluorescent chemosensor, test kits and fluorescent display materials for Fe3+ and F−. Graphical abstract Novel supramolecular organic framework gel PQPA was constructed by functionalized pillar[5]arenes. Interestingly, the SOF gel PQPA could continuously and ultrasensitively detect Fe3+ and F− in water. Unlabelled Image Highlights • Novel pillar[5]arene-based SOF gel (PQPA) was successfully constructed. • PQPA could carry out ultrasensitive detection of Fe3+ in water (LOD = 0.102 nM). • PQPA-Fe could ultrasensitively detect F− in water (LOD = 9.79 nM). • Fe3+ could be adsorbed by PQPA from water (adsorption rate of 99.9%). • Test kits for Fe3+ and F− were prepared. [ABSTRACT FROM AUTHOR]

The propagation and multiple scattering of non-homogeneous shear waves resulting from two cavities embedded in exponential functional graded materials (FGMs) were investigated, and the dynamic stress around the two cavities derived. The non-homogeneous scattering fields of shear waves around the cavities are analytically expressed by using the wave function expansion method. The interaction of non-homogeneous scattering fields between the two cavities is described accurately. The dynamic stresses around the cavities under different geometrical and physical parameters are graphically illustrated and analyzed. Analysis shows that the non-homogeneous properties of FGMs exhibit a significant effect on the dynamic stress around the cavities. The effect of the non-homogeneous properties of FGMs on the dynamic stress is also dependent on the gradation direction, the distance between the two cavities, the relative position of the two cavities and the incident frequency of waves. A comparison with other existing studies in the literature is also presented. [ABSTRACT FROM AUTHOR]

Abstract Rotavirus gastroenteritis is an important pediatric disease in China. In a survey of rotavirus infection at two sentinel hospitals in China (Beijing Friendship Hospital and Changchun Children’s Hospital), 296 cases were detected. A total of 283 (95.6%) cases of rotavirus infection occurred in children under 5 years of age. Serotype G1 (62%) was most prevalent followed by G2 (28.5%), G3 (5%) and G4 (2%). Mixed infections (n=8, 3%) were rare, and 16 isolates (5.5%) remained non-typeable. A consistent epidemic occurred during the winter. Rotavirus was responsible for about 61.8% of diarrhea-related hospitalizations in children under 5 years of age, with a mean hospital stay of 5.6 days (1.0–21 days). The estimated rate of rotavirus-attributed hospitalizations was 16/1000 children under 5 years of age per year. Rotavirus-related death is rare in Changchun and Beijing. The present findings suggest that a rotavirus vaccine for the prevention of severe disease and a reduction of treatment costs would be of significant benefit to China. [ABSTRACT FROM AUTHOR]