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High thermal stability and low mechanical sensitivity are two major goals in development of energetic compounds. Six highly stable insensitive polynitrophenyl substituted furazan (furoxan) annelate...

With good contrast in T1and T2weighted imaging as well as low toxicity in 3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, this work proposes the cross-linked polydimethylsiloxane colloids as a novel non-ionic contrast agent for gastrointestinal magnetic resonance imaging. The experiments of nuclear magnetic resonance spectra and relaxation show that within the interface of the colloids, there are nuclear Overhauser effect and transient nuclear Overhauser effect (cross-relaxation). Regarding the longitudinal relaxation experiments of CH2CH2O segments of Tween 80, a two spins system is found and modeled well by the equation [Formula: see text] which is deduced based on the transient nuclear Overhauser effect proposed by Solomon. The arbitrary constant X is additionally added with the initial conditions ( Iz − I0)t=0 = −2 XS0and ( Sz − S0)t=0 = −2 S0. For the two spins system, D1and T1are corresponding to longitudinal relaxation times of the bound water and the CH2CH2O respectively. Concerning the transverse relaxation experiments of the CH2CH2O, they agree with the equation with three exponential decays, defined by three relaxation times, likely corresponding to three mechanisms. These mechanisms possibly are intramolecular and intermolecular dipole–dipole (DD) interactions and scalar coupling. Within the interface, hydrogen bonding causes the positive nuclear Overhauser effect of the CH2CH2O’s nuclear magnetic resonance spectra, the transient nuclear Overhauser effect of the CH2CH2O’s longitudinal relaxation experiments and the intermolecular dipole–dipole interactions of the CH2CH2O’s transverse relaxation experiments.

Chilling has become a major meteorological disaster affecting the spring maize (Zea mays L.) production region in Northeast China. Our objective was to assess the effect of a novel plant growth regulator on relieving chilling stress among early- and late-maturing maize cultivars in three different regions in Northeast China. Field experiments were conducted in Haerbin country, Suihua country, and Yi-an county in 2011 and 2012. Two widely planted maize cultivars (early maturing—‘Fengdan 3’ and late maturing—‘Zhengdan 958’) in Northeast China were planted. A PKN (a combination of synthetic plant growth regulator, its principal components were polyaspartic acid, kinetin and α-naphthalene acetic acid) solution was applied to the maize surfaces at the six-expanded-leaf stage. The results demonstrated that spring maize yield was significantly influenced by region, cultivar and PKN; spring maize planted in the low-latitude region (Haerbin) had a higher yield than that in the high-latitude region (Suihua and Yi-an countries); the late-maturing cultivar had a higher yield than the early-maturing cultivar. In comparison to the control treatment, the PKN treatment increased the spring maize yield significantly. The variation in the grain yield across regions, cultivars and PKN treatments was mainly due to variation in the kernel weight. Compared to the control, the PKN treatment significantly increased kernel weight. Moreover, the PKN treatment increased the leaf area index, net assimilation rate, ear-leaf sucrose content, and sucrose synthase and sucrose phosphate synthase activities. In addition, the abovementioned indicators increased more for late-maturing cultivars than for early-maturing cultivars in the high-latitude region. In conclusion, PKN can be used to partly relieve chilling stress for spring maize, especially for late-maturing cultivars in high-latitude regions.

A synthetic heavier p-block bismuth (Bi) complex with a rigid pincer ligand, is shown to be a Bi-based molecular electrocatalyst for proton reduction under weak acid conditions. High activity of the complex is observed in catalysis, with a icat/ip value of 95 with CH3CO2H. Experimental and theoretical studies indicate that the hydrogen evolution reaction (HER) mechanism involves generating a low-valent BiI complex and its reactivity toward acid to form a BiIII-hydride species. Subsequent protonolysis of the BiIII-hydride eliminates H2 through a heterolytic route. The HER cycling through the low-valent metal species and its hydride has been proposed previously in transition-metal (TM) centered catalysts but rarely validated in main-group catalytic systems. The finding brings insight into heavier main-group Bi-catalyzed H2 evolution and the role of low-valent main-group metal centre during catalysis.

Aromatic diimide dyes are an attractive class of redox-active organic molecules for lithium-ion batteries, whose battery performances (stabilities, conductivities and cyclicities) are strongly dependent on the sizes of their π-systems. However, due to the different Clar’s structures possessed, three vertically π-extended aromatic diimides, namely, naphthalene diimide (two one-electron reductions), perylene diimide and terrylene diimide (two one-electron reductions), exhibit different electronic redox mechanisms when served as cathode materials in organic lithium-ion batteries. Herein, we have studied carefully the different electrochemical characteristics of the three aromatic diimides through experimental and theoretical calculations. Their battery present different shape of charge/discharge curves resulting from stability of their reduction state during charge/discharge process. Terrylene diimide shows better cycle and rate capacities than those of naphthalene diimide and perylene diimide, which could be attributed to the more energies released during terrylene diimide combining with lithium ions than those of other two diimides.

Bay-substituted perylene diimide (PDI) dyes are a subject of great interest in both industrial and academic domains in the past decades. As important laterally extended derivatives of PDI dyes, benzo[ghi]perylenetriimides (BPTIs) have attracted much attention as non-fullerene acceptors, but their scope for applications has been limited by the lack of substitutions at the remaining two bay positions. Herein, we reported a facile synthesis of a novel, highly valuable synthon, 7, 8-dichlorobenzo[ghi]perylenetriimide (2), with two easy leaving chlorine groups at the remaining bay area, which can be further substituted by other functionalized groups through various synthetic strategies. Due to foreseeable applications of core-functionalized BPTIs, this unique synthon is anticipated to open up a fresh ground for optoelectronic materials.

Three new compounds, namely massonside C (1), massonianoside F (2), and 3, 8-dimethyl- herbacetin-7-O-β-D-glucopyranoside (3), together with five known compounds (4-8), were isolated from the fresh needles of Pinus massoniana. Their structures were established by 1D, 2D NMR, HRMS and comparison with the literature data. The absolute configuration of 1 was confirmed by a combination of X-ray single crystal analysis. All isolated compounds were evaluated for the protective effect of human umbilical vein endothelial cells against oxidative damage.

The anions in electrolytes are the carriers of lithium ions for lithium-organic redox flow batteries. Herein, we reported that the interactions between the electrolyte anions and electron-deficient redox-active organic molecules (anion-π interactions) have strong influences on the battery properties due to the anion-π-induced formation of radical anions or sandwich-like aggregates.

At the molecular level, the circadian clock is regulated by a time delayed transcriptional-translational feedback loop in which the core proteins interact with each other rhythmically to drive daily biological rhythms. The C-terminal domain of a key clock protein PER2 (PER2c) plays a critically important role in the loop, not only for its interaction with the binding partner CRY proteins but also for the CRY/PER complex's translocation from the cytosol to the nucleus. Previous circular dichroism (CD) spectroscopic studies have shown that mouse PER2c (mPER2c) is less structured in solution by itself but folded into stable secondary structures upon interaction with mouse CRYs. To understand the stability and folding of human PER2c (hPER2c), we expressed and purified hPER2c. Three oligomerization forms of recombinant hPER2c were identified and thoroughly characterized through a combination of biochemical and biophysical techniques. Different to mPER2c, both thermal unfolding DLS and CD analyses suggested that all forms of hPER2c have very stable secondary structures in solution by themselves with melting temperatures higher than the physiological body temperature, indicating that hPER2c does not require CRY to fold. Furthermore, we examined the effects of EDTA, salt concentration, and a reducing agent on hPER2c folding and oligomerization. The ability of hPER2c forming oligomers reflects the potential role of hPER2c in the assembly of circadian rhythm core protein complexes.

Donor–acceptor heterostructures have attracted much interest in current optoelectronic technologies because they can control the charge dynamics in these applications. To improve the charge-carrier generation and transport properties, the donor and acceptor components in the heterostructures have a better interface at the molecular level with bicontinuous structures. So far, most available examples are obtained by a self-assembly approach from two organic semiconducting molecules. Considering the complementary properties of inorganic and organic semiconductors, the self-assembly of semiconductive inorganic and organic components in one material is anticipated to form abnormal hybrid heterostructures with synergetic properties. However, so far, only a few such hybrid heterostructures have been reported, most of which involved in the inorganic components as electron donors. Herein we reported that the combination of 2,5-bis-(4-pyridinium)thiazolo[5,4-d]thiazole (Py2TTz) with Cu2+ in the presence of acetonitrile by a solvothermal method led to a novel bicontinuous hybrid heterostructure [Cu2(Py2TTz)(CN)2]·0.5(Py2TTz) (1) with semiconducting Py2TTz and in situ synthesized CuCN as the electron donor and acceptor components. Due to the strong coordination combined with cation–π interactions between the two semiconducting components, this hybrid exhibits enhanced photocatalytic activities towards the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO) in comparison with those of the two individual bulk semiconductive Py2TTz and CuCN.

An acidic ionic liquid modified microfiber attapulgite (MFA)-supported nickel was prepared by thermally decomposing nickel tetracarbonyl onto MFA modified with an acidic ion liquid (AIL, 1-sulfobutyl-3-methylimidazolium trifluoromethanesulfonate). It was characterized with multiple instruments and used for catalyzing hydroconversion of coal-related model compounds (CRMCs) di(1-naphthyl)methane, diphenylmethane, bibenzyl, and 1,3-diphenylpropane. The results indicate that Ni/MFA@AIL effectively catalyzes hydroconversion of the CRMCs to afford cyclanes and alkylcyclanes by inducing the formation of H + , H − , and biatomic active hydrogen species.

The adsorption and photodegradation performance are of paramount importance to photocatalysts in environmental hazards, especially in serious organic pollutants leaking emergency in the absence of natural light illumination. Here we demonstrated a surface ligand assisted localized crystallization (SLALC) method to scale synthesis of cubic phase NaNbO 3 (c-NaNbO 3 ) photocatalyst at a low temperature as 350 °C. The as synthesized c-NaNbO 3 nanoparticles could adsorb 95% of methylene blue (MB) in 3 min and photodegrade 99.3% of MB in 180 min. Moreover, the as prepared c-NaNbO 3 nanoparticles exhibit both outstanding adsorption and photodegradation recoverability, which shows great potential in actual environmental conservation.

The ambient solution reaction of silver salt (CF3COOAg) with a heterolytic thiolate gave rise to the isolation of an air-stable sub-nanometer sized hexanuclear silver(I) cluster, Ag6(dmmp)6‧6CH3OH (1, Hdmmp = 4,6-dimethyl-2-mercaptopyrimidine). X-ray single-crystal structural analysis shows that the Ag66+ core in 1 is a distorted octahedron surrounded by six depronated dmmp ligands as protecting units with each through a simple μ3-bridging coordinating motif. The shortest Ag–Ag bond distance of 2.835 A in the Ag66+ unit, suggests a closed shell d10‧‧‧d10 argentophilic interactions. DFT studies indicate that the HOMO in 1 is largely composed of d orbitals of AgI ions, while the LUMO mainly consists of s orbitals of AgI ions and p orbitals of S atoms. Hirshfeld surface analysis was also performed to analyze the nature of intermolecular interactions of 1. Complex 1 shows a yellow emission at λmax = 566 nm in the solid state upon excited at 395 nm and antibacterial activity.

In this contribution, a bisthienyl-substituted Bodipy sensitizer (B1) was synthesized and further axially anchored to one cobalt catalytic center via a pyridyl group located in the 8-position of the B1, affording a new sensitizer-catalyst supramolecular assembly (Co-B1). The supramolecular structure of Co-B1 was determined through single-crystal X-ray diffraction analysis, and showed nearly orthogonal stereochemistry between sensitizer B1 and Co catalyst. Visible light-driven H2-evolution performance of Co-B1 was investigated in aqueous solution with triethylamine (Et3N) as an electron donor, which displayed efficient H2 evolution activity and stability. DFT calculations indicated transition of HOMO → LUMO from the π-conjugated Bodipy B1 anion to the Co fragment is an intramolecular electron-transfer process. Notably, the present artificial photosynthetic system is an example of an absolutely noble-metal free supramolecular system for photochemical H2 generation from water using non-halogenated dye-catalyst assembly.

The effect of destabilization at (960°C,1000°C,1050°C) followed by sub-critical heat treatment (SCHT) at (260°C, 450°C, 550°C) on microstructure and mechanical properties of a hypereutectic chromium cast iron containing 31 wt.% Cr was investigated. The response of the microstructure of the specimens differed significantly to heat treatment. With increasing destabilization temperature, the amount of retained austenite increased and it became more stable during following SCHT. The peak values of bulk hardness deceased with increasing destabilization temperature, while higher SCHT was needed to reach the hardness maximum. The hardness and erosion wear property of the specimens destabilization at 960°C or 1000°C deteriorated after SCHT at 550°C due to the formation of ferrite/carbide product, which was not found in the specimens destabilization at 1050°C followed by SCHT at 550°C. The specimen destabilization at 960°C + SCHT at 260°C performed best erosion wear resistance with matrix of martensite containing little austenite.

Isolariciresinol-9'-O-α-L-arabinofuranoside (MWS‑19) isolated from Pinus massoniana Lamb. Fresh pine needles is the major ingredient of the Songling Xuemaikang capsule therapy used for hypertension. The present study aimed to investigate the effects and underlying mechanisms of MWS‑19 on hydrogen peroxide (H2O2)‑induced apoptosis in human umbilical vein endothelial cells (HUVECs). To investigate the effect of MWS‑19 on apoptosis in HUVECs, an oxidative stress‑induced apoptosis model was established in HUVECs using H2O2, and the present study performed Hoechst 33258 staining and a Cell Counting Kit‑8 (CCK‑8) assay. Furthermore, western blot analysis was also performed to investigate the underlying mechanism of the effects of MWS‑19 on the model. The results demonstrated that MWS‑19 reversed the effects of H2O2 on cell apoptosis at a concentration range of 15.6‑250 µg/ml, with dose‑dependent increases in cell growth. Hoechst staining indicated that 500 µM H2O2 induced HUVEC apoptosis, and MWS‑19 markedly protected HUVECs against apoptosis at 31.3, 62.5 and 125 µg/ml. Furthermore, the protein expression of phosphatidylinositol 3‑kinase (PI3K), phosphorylated‑Akt and Bcl‑2‑associated agonist of cell death (Bad) were increased, and reduced caspase‑3 activation was observed, following treatment with MWS‑19 in H2O2‑treated HUVECs. Additionally, the PI3K inhibitor wortmannin attenuated PI3K/Akt/Bad signaling induced by MWS‑19 treatment and neutralized the effect of MWS‑19 on the growth of HUVECs. In conclusion, the results of the present study indicate that MWS‑19 may protect against H2O2‑induced HUVEC apoptosis via the PI3K/Akt/Bad signaling pathway. MWS‑19 may serve an important role in the prevention of oxidative damage in vascular endothelial cells in hypertension patients.

Sesuvium portulacastrum, a promising facultative halophyte species, has a remarkable ability to survival at severe salt of ~1000 mM NaCl. However, genes encoding proteins involved in the process of salt tolerance in S. portulacastrum are limited. In this study, suppression subtractive hybridization together with reverse northern blot analysis and RT-PCR was used to identify up-regulated genes in roots after treatment with seawater for 2–24 h. We identified a total of 148 unigenes, and most of these genes were predominantly associated with ‘signal transduction and transcription’, ‘stress/defense response’, ‘transport’ and ‘metabolism’. Comparative analysis between physiological response and differentially expressed genes highlighted that sodium (Na+) transport, compartmentation, reactive oxygen species (ROS) scavenging, and sugar-metabolizing regulation play important roles in salt tolerance of S. portulacastrum, whereas inhibition of root elongation induced by high salinity may be related to lignin deposition and disruption of calcium homeostasis.

The economics of bio-solvent production are largely dependent on the cost of the fermentation substrate. Dioscorea zingiberensis C.H. Wright (DZW), the main raw material used to produce saponin, contains 13-18% starch which can be directly saccharified to a saccharification liquid of DZW starch (SLDS) that contains abundant nutrients. In this study, the water-soluble micromolecule compounds in SLDS were quantified through 1H NMR. Using SLDS as the substrate to conduct ABE fermentation by Clostridium beijerinckii, the fermentation cycle was shortened 24h, the maximum biomass and consumption rate of the glucose significantly increased, and the productivity of total solvents were increased by 0.244±0.010g/L/h compared to standard P2 medium. Expression analysis of genes encoding key enzymes involved in acetone and butanol production and glucose consumption showed that they were induced by SLDS. Taken together, SLDS is a useful and renewable glycosylated solution for ABE fermentation.

As a key virulence factor of Mycobacterium tuberculosis, EsxA or 6-kDa early secreted antigenic target (ESAT-6) has been implicated in phagosome rupture and mycobacterial translocation from the phagosome to the cytosol within macrophages. Our previous studies have shown that EsxA permeabilizes liposomal membrane at acidic pH and a membrane-permeabilization defective mutant Q5K attenuates mycobacterial cytosolic translocation and virulence in macrophages. To further probe the mechanism of EsxA membrane permeabilization, here we characterized the effects of various lipid compositions, including biologically relevant phagosome-mimicking lipids and lipid rafts, on the structural stability and membrane insertion of EsxA WT and Q5K. We have found a complex dual play of membrane fluidity and charge in regulating EsxA membrane insertion. Moreover, Q5K affects the membrane insertion through a structure- and lipid composition-independent mechanism. The results of this study provide a novel insights into the mechanism of EsxA membrane interaction.

In the last three decades, many giant DNA viruses have been discovered. Giant viruses present a unique and essential research frontier for studies of self-assembly and regulation of supramolecular assemblies. The question on how these giant DNA viruses assemble thousands of proteins so accurately to form their protein shells, the capsids, remains largely unanswered. Revealing the mechanisms of giant virus assembly will help to discover the mysteries of many self-assembly biology problems. Paramecium bursaria Chlorella virus-1 (PBCV-1) is one of the most intensively studied giant viruses. Here, we implemented a multi-scale approach to investigate the interactions among PBCV-1 capsid building units called capsomers. Three binding modes with different strengths are found between capsomers around the relatively flat area of the virion surface at the icosahedral 2-fold axis. Furthermore, a capsomer structure manipulation package is developed to simulate the capsid assembly process. Using these tools, binding forces among capsomers were investigated and binding funnels were observed that were consistent with the final assembled capsid. In addition, total binding free energies of each binding mode were calculated. The results helped to explain previous experimental observations. Results and tools generated in this work established an initial computational approach to answer current unresolved questions regarding giant virus assembly mechanisms. Results will pave the way for studying more complicated process in other biomolecular structures.

A new series of 7-substituted 3-arylcoumarins was designed, synthesized and evaluated as novel antitumor agents in vitro. It was found that several compounds of them exhibit activity in vitro against SK-HEP-1(hepatocellu- lar carcinoma), HepG2(hepatocellular carcinoma) and SGC7901(gastric carcinoma) cell lines to some extent. Moreover, compounds 5a, 5b, 6a and 6b have better activity against HeLa(cervical carcinoma) cell and their half maximal inhibitory concentration(IC50, μmol/L) values are less than 10.

Two kinds of polytetrafluoroethylene (PTFE) composites PTFE/GF/Gr (sample 1) and PTFE/GF/Gr/Cu (sample 2) were prepared by mixed molding method. X-ray diffraction results show that sample 2 is crystal structure, while sample 1 is amorphous/crystal structure. They were processed into the bearing bushes, which were installed on the water pump bearing to study the influence of different structures on friction properties by rotating bearing. Experimental results reveal that the wearing rate of sample 2 is much higher than that of sample 1. From the optical microscope and SEM analysis of the worn surface, it indicates that the wearing mechanism of sample 1 with amorphous structure is adhesive wearing, while that of sample 2 is abrasive and fatigue wearing mechanism. Our results indicate that the PTFE composition with amorphous matrix can be used to sliding bearings because of its ideal self-lubricating properties.

Two new sesquiterpene glycosides, namely massonside A (1) and massonside B (2), were isolated from the n-Bu extract of the fresh needles of Pinus massoniana Lamb. Their structures were established by 1D, 2D nuclear magnetic resonance and high-resolution mass spectrometry. Their biological activities were profiled by the anti-HBV and anti-HCV assays.

Puerarin, a known isoflavone, is commonly found as a Chinese herb medicine. It is widely used in China to treat cardiac diseases such as angina, cardiac infarction and arrhythmia. However, its cardioprotective mechanism remains unclear. In this study, puerarin significantly prolonged ventricular action potential duration (APD) with a dosage dependent manner in the micromolar range on isolated rat ventricular myocytes. However, submicromolar puerarin had no effect on resting membrane potential (RMP), action potential amplitude (APA) and maximal velocity of depolarization (Vmax) of action potential. Only above the concentration of 10 mM, puerarin exhibited more aggressive effect on action potential, and shifted RMP to the positive direction. Millimolar concentrations of puerarin significantly inhibited inward rectified K+ channels in a dosage dependent manner, and exhibited bigger effects upon Kir2.1 vs Kir2.3 in transfected HEK293 cells. As low as micromolar range concentrations of puerarin significantly inhibited Kv7.1 and IKs. These inhibitory effects may due to the direct inhibition of puerarin upon channels not via the PKA-dependent pathway. These results provided direct preclinical evidence that puerarin prolonged APD via its inhibitory effect upon Kv7.1 and IKs, contributing to a better understanding the mechanism of puerarin cardioprotection in the treatment of cardiovascular diseases.

To investigate the value of hydrogen proton magnet resonance spectroscopy (1H-MRS) in the differential diagnosis of multiple-domain amnestic mild cognitive impairment (M-aMCI) and vascular cognitive impairment with no dementia (VCIND); 1H-MRS was performed in patients with M-aMCI and VCIND. The level was determined for N-acetylaspartate (NAA), glutamate (Glu), inositol (mI), choline (Cho), and creatine (Cr). Compared with the normal control group, the NAA–Cr ratio in all regions studied was significantly lower in the M-aMCI and VCIND groups. The Glu–Cr ratio in the posterior cingulate gyrus of the M-aMCI group was significantly lower than in the VCIND. The mI–Cr ratio in the frontal white matter of the VCIND was significantly higher than in the M-aMCI group. In the white matter adjacent to the lateral ventricles, the Cho–Cr ratio was significantly higher in the VCIND than the M-aMCI. Our results suggested 1H-MRS is an effective method in the differential diagnosis of M-aMCI and VCIND.

The internal void of cross wedge rolling (CWR) part can be treated as porous material due to their similar physical property and deformation characteristics. Aiming at the CWR process of aluminum alloy 7075 workpiece, the numerical simulation model for internal void was established by means of the rigid-plastic FEM method for the porous material. The relative density was used to research the influence of three primary parameters on the internal void in CWR process, including the forming angle α1, the stretching angle β and the area reduction ΔA. The experimental results show that the expansion of internal void occurs in the stretching zone, and the knifing zone just has a little influence on it. The stretching angle has a great influence on the internal void, while the area reduction has a small influence on it. The size of internal voids decreases with the increase of area reduction, stretching angle and forming angle. When designing the CWR tool geometry and operating conditions, to prevent the internal void, the area reduction is suggested to be 55%–65%, the stretching angle to be 8°–10°, and the forming angle to be 29°–32°.

Three new bisabolocurcumin ethers, named demethoxybisabolocurcumin ether (1), bisabolocurcumin ether (2), and didemethoxybisabolocurcumin ether (3), along with two known compounds, 4 and 5, were isolated from the AcOEt extract of the rhizomes of Curcuma longa L. Their structures were established by the analysis of NMR and MS data. The new compounds 1–3, which possess a new 1,7-diarylheptanoid skeleton linked with a bisabolone-type sesquiterpene substructure by a CO bond, were found for the first time in a natural source.

A series of purine nucleoside analogues bearing an aryl and hetaryl group in position 6 were prepared and their biological activities were assessed by in vitro CDK1/Cyclin B1 and CDK2/Cyclin A2 kinase assay. From the synthesized chemicals, three Xylocydine derivatives 3h, 3i, and 3j exhibited specific inhibitory activities on CDK2/Cyclin A2 with IC(50) values of 4.6, 4.8, and 55 μM, respectively. Those three compounds all induced G1/S phase arrest in Human epithelial carcinoma cell line (HeLa), and the results suggested they may inhibit CDK2 activity in vitro. Furthermore, molecular modeling study, their docking into Cyclin Dependant Kinase 2 (CDK2) active site showed high docking scores. Taken together, these data suggest that, those three compounds are good inhibitors of CDK2 for studying this kinase signal transduction pathway in cell system.

A new skeleton bisabolane-type sesquiterpene curcuminoid, bisabocurcumin ( 1 ), along with 5 known compounds, curcumin ( 2 ), demethoxycurcumin ( 3 ), bidemethoxycurcumin ( 4 ), (1 E ,4 E )-1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-1,4-dien-3-one ( 5 ), and (1 E ,4 E )-1-(4-hydroxy-3-methoxyphenyl)-5-(4-hydroxy phenyl-)-penta-1,4-dien-3-one ( 6 ) were isolated from the rhizomes of Curcuma longa L. Their structures were determined on the basis of spectroscopic analysis. Bisabocurcumin ( 1 ) is firstly obtained from nature with a new skeleton combined by a bisabolane-type sesquiterpene and a 1,7-diphenylheptanoid through a C–C bond.

Nafion–titanate nanotubes composite membranes prepared through casting process have been investigated as electrolytes for polymer electrolyte membrane fuel cell applications under low relative humidity. The glass transition temperature and the decomposition temperature of composite membrane at dry state are higher than those of pristine Nafion membrane. Cracks have been observed in the membrane at the concentration of nanotubes above 5 wt.%. The maximum proton conductivity at 100 °C and 50% relative humidity is observed with the concentration of doped titanate nanotubes of 5 wt.%. Solid nuclear magnetic resonance spectrum is applied to qualitatively characterize the status of water inside the membrane at different temperatures. The power densities at 0.8 V for cell assembled from composite membrane containing 5 wt.% of titanate nanotubes are about 13% and 35% higher than that for plain Nafion cells under 50% relative humidity at 65 °C and 90 °C, respectively.

A novel strain of the class Actinobacteria was isolated from a seawater sample collected in the South China Sea using modified R2A agar plates. The strain was a Gram-stain-positive, non-motile, non-spore-forming, catalase-positive, irregular rod-shaped bacterium. The strain grew at 4–45 °C and pH 5.0–10.2, and tolerated 5 % (w/v) NaCl. Based on its 16S rRNA gene sequence, the organism was related phylogenetically to members of the genera Fodinibacter (96.7 % similarity), Lapillicoccus (96.5 %), Knoellia (95.0–95.8 %), Oryzihumus (95.6 %) and Humibacillus (95.6 %). The cell-wall contained l-ornithine as the major diagnostic diamino acid in the peptidoglycan. MK-8(H4) was the predominant menaquinone. Major cellular fatty acids were iso-C18 : 1 ω9c, iso-C16 : 0, iso-C15 : 0 and C17 : 0. The G+C content of the DNA was 69.6 mol%. Phenotypic and phylogenetic data revealed that this strain represents a novel species in a new genus of the family Intrasporangiaceae, for which the name Ornithinibacter aureus gen. nov., sp. nov. is proposed; the type strain of Ornithinibacter aureus is HB09001T (=CGMCC 1.10341T =DSM 23364T).

We studied the reformation processes for structure I (sI) (methane, carbon dioxide) and structure II (sII) (propane) gas hydrates experimentally and investigated the memory effects between sI and sII hydrates using a constant-volume system. During these experiments, the induction period for hydrate formation was observed. Moreover, we also found that there were obvious memory effects in secondary formation of sI gas hydrates as well as in alternate secondary formation of sI and sII gas hydrates.

An exothermic reaction between MgB2 and water was observed in our laboratory at high temperature, although no obvious reaction occurred at room temperature. The reaction process of MgB2 and water was therefore studied by using microcalorimetry. The results showed that the reaction enthalpies of MgB2 with water and the formation enthalpies of MgB2 at T = (323.15, 328.15, 333.15 and 338.15) K are (–313.15, –317.85, –322.09, –329.27) kJ?mol–1, and (–238.96, –237.73, –236.50, –234.30) kJ●mol–1, respectively. The standard enthalpy of formation and standard molar heat capacity of MgB2 obtained by extrapolation method are –245.11 kJ●mol–1 and 246 J●mol–1●K–1, respectively. The values of activation energy E, pre-exponential factor A and the reaction order for the reaction of MgB2 and water over the temperature range from 323.15 K to 338.15 K are 50.80 kJ●mol–1, 104.78 s–1 and about 1.346, respectively. The positive values of ΔG≠ and ΔH≠ and negative value of ΔS≠ indicate that the reaction can take place easily above 314.45 K.

Proton exchange membranes consisting of Nafion® and crystallized titania nanoparticles have been developed to improve water-retention and proton conductivity at elevated temperature and low relative humidity. The anatase-type titania nanoparticles were synthesized in situ in Nafion solution through sol–gel process and the size of the formed titiania nanoparticles is in the range of 3–6 nm. The formed nanoparticles are well-dispersed in Nafion solution at the titania concentration of 5 wt %. The glass transition temperature of the formed Nafion-titania composite membrane is about 20oC higher than that of plain Nafion membrane. At elevated temperature (above 100°C), the Nafion-titania nanocomposite membrane shows higher water uptake ability and improved proton conductivity compared to pure Nafion membrane. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Hsp90 is a ubiquitous molecular chaperone that plays a key role in the malignant development of hormone-dependent pathologies such as cancer. An important role for Hsp90 is to facilitate the stable binding of steroid hormones to their respective receptors enabling the ligand-based signal to be carried to the nucleus and ultimately resulting in the up-regulation of gene expression. Along with Hsp90, this dynamic and transient process also involves the recruitment of additional proteins and co-chaperones that add further stability to the mature receptor-chaperone complex. In the work presented here, we describe four new protocols for the bacterial over-expression and column chromatographic purification of the human p23, FKBP52, HOP and SGTα proteins. Each of these proteins plays a distinct role in the steroid hormone receptor regulatory cycle. Affinity, ion-exchange and size-exclusion techniques were used to produce target yields greater than 50mg/L of cultured media, with each purified sample reaching near absolute sample homogeneity. These results reveal a reliable system for the production of p23, FKBP52, HOP and SGTα substrate proteins for use in the investigation of the Hsp90-associated protein interactions of the steroid hormone receptor cycle.

Nafion-titanate nanotubes composite membranes were prepared through a casting process. With the addition of 5 wt.%, the nanotubes were homogenously distributed in Nafion solution. The formed composite membrane showed a comparable mechanical strength to Nafion membrane. The proton conductivity of the composite membrane without external humidification is higher than that of the Nafion membrane, reaching 0.034 Scm−1 and 0.01 Scm−1 at 100 °C and 120 °C, respectively. The improved proton conductivity was attributed to the great water retention ability of the doped nanotubes.

4-Methyl-8-hydroxylpsoralen (MXan) and 4,9-dimethyl-8-hydroxylpsoralen (DMXan) were synthesized in order to clarify the effect of methyl on the antioxidant effectiveness of xanthotoxol (8-hydroxylpsoralen, Xan), which were assessed by bleaching β-carotene in linoleic acid–Triton emulsion, by interacting with 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS + ), 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH), and galvinoxyl radical, and by protecting DNA against the oxidation induced by Cu 2+ /glutathione (GSH) and 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH). Methyl attaching to xanthotoxol did not affect its ability to protect linoleic acid against autoxidation and to inhibit Cu 2+ /GSH-induced oxidation DNA, but decreased its ability to scavenge ABTS + and DPPH, and to protect DNA against AAPH-induced oxidation. Therefore, methyl attenuated the antioxidant effectiveness of xanthotoxol in radical-induced oxidation of DNA.

The program RIVEM (Radial Interpretation of Viral Electron density Maps) was developed to project density radially onto a sphere that is then presented as a stereographic diagram. This permits features resulting from an asymmetric reconstruction to be projected and positioned onto an icosahedral virus surface. The features that constitute the viral surface can also be simultaneously represented in terms of atoms, amino acid residues, potential charge distribution, and surface topology. The procedure can also be adapted for the investigation of various molecular interactions.

The most extensive structural information on viruses relates to apparently icosahedral virions and is based on X-ray crystallography and on cryo-electron microscopy single-particle reconstructions. This paper concerns itself with the study of the macromolecular complexes that constitute viruses, using structural hybrid techniques., The most extensive structural information on viruses relates to apparently icosahedral virions and is based on X-ray crystallography and on cryo-electron microscopy (cryo-EM) single-particle reconstructions. Both techniques lean heavily on imposing icosahedral symmetry, thereby obscuring any deviation from the assumed symmetry. However, tailed bacteriophages have icosahedral or prolate icosahedral heads that have one obvious unique vertex where the genome can enter for DNA packaging and exit when infecting a host cell. The presence of the tail allows cryo-EM reconstructions in which the special vertex is used to orient the head in a unique manner. Some very large dsDNA icosahedral viruses also develop special vertices thought to be required for infecting host cells. Similarly, preliminary cryo-EM data for the small ssDNA canine parvovirus complexed with receptor suggests that these viruses, previously considered to be accurately icosahedral, might have some asymmetric properties that generate one preferred receptor-binding site on the viral surface. Comparisons are made between rhinoviruses that bind receptor molecules uniformly to all 60 equivalent binding sites, canine parvovirus, which appears to have a preferred receptor-binding site, and bacteriophage T4, which gains major biological advantages on account of its unique vertex and tail organelle.

Anthrax toxin receptors act as molecular clamps or switches that control anthrax toxin entry, pH-dependent pore formation, and translocation of enzymatic moieties across the endosomal membranes. We previously reported that reduction of the disulfide bonds in the immunoglobulin-like (Ig) domain of the anthrax toxin receptor 2 (ANTXR2) inhibited the function of the protective antigen (PA) pore. In the present study, the disulfide linkage in the Ig domain was identified as Cys255-Cys279 and Cys230-Cys315. Specific disulfide bond deletion mutants were achieved by replacing Cys residues with Ala residues. Deletion of the disulfide bond C255-C279, but not C230-C315, inhibited the PA pore-induced release of the fluorescence dyes from the liposomes, suggesting that C255-C279 is essential for PA pore function. Furthermore, we found that deletion of C255-C279 did not affect PA prepore-to-pore conversion, but inhibited PA pore membrane insertion by trapping the PA membrane-inserting loops in proteinaceous hydrophobic pockets. Fluorescence spectra of Trp59, a residue adjacent to the PA-binding motif in von Willebrand factor A (VWA) domain of ANTXR2, showed that deletion of C255-C279 resulted in a significant conformational change on the receptor ectodomain. The disulfide deletion-induced conformational change on the VWA domain was further confirmed by single-particle 3D reconstruction of the negatively stained PA-receptor heptameric complexes. Together, the biochemical and structural data obtained in this study provides a mechanistic insight into the role of the receptor disulfide bond C255-C279 in anthrax toxin action. Manipulation of the redox states of the receptor, specifically targeting to C255-C279, may become a novel strategy to treat anthrax.

SummaryDengue virus (DENV) is a significant human pathogen that causes millions of infections and results in about 24,000 deaths each year. Dendritic cell-specific ICAM3 grabbing nonintegrin (DC-SIGN), abundant in immature dendritic cells, was previously reported as being an ancillary receptor interacting with the surface of DENV. The structure of DENV in complex with the carbohydrate recognition domain (CRD) of DC-SIGN was determined by cryo-electron microscopy at 25 Å resolution. One CRD monomer was found to bind to two glycosylation sites at Asn67 of two neighboring glycoproteins in each icosahedral asymmetric unit, leaving the third Asn67 residue vacant. The vacancy at the third Asn67 site is a result of the nonequivalence of the glycoprotein environments, leaving space for the primary receptor binding to domain III of E. The use of carbohydrate moieties for receptor binding sites suggests a mechanism for avoiding immune surveillance.

Molecular absorption in an enhanced resonance light scattering (RLS) system decreases the enhanced RLS signals detected by using a common spectrofluorometer, lowering the detection sensitivity of RLS method. Thus a mathematical compensation for the decreased RLS signals resulting from the molecular absorption in the detection system is necessary so as to improve the detection sensitivity. Starting from Beer's law, herein we propose a compensation method by calculating a compensation factor related to the transmittance after the incident beam has passed through the absorption system. The compensation factor can be measured with an equipped accessory of the spectrofluorometer introducing a cell holder to change the propagation direction of the excitation light beam of the spectrofluorometer. By taking the interaction of Ponceau G (PG) with proteins as an example, we proved that the present compensation for the molecular absorption-decreased RLS signals could improve the detection sensitivity about ...

In an acidic medium, the interaction of Fast red VR (FRV) with proteins such as bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep), α-chymotrypsin (Chy), and lysozyme (Lys) was characterized by measuring enhanced resonance light-scattering (RLS) signals. It was found that the enhanced RLS intensities of FRV by proteins at 287.0 nm were in proportion to the concentrations of proteins above, and the limits of determination for BSA, HSA, Lys, γ-IgG were below 25 ng/mL. The present method was successfully applied to the determinations of proteins in synthetic samples, and the total content of proteins in human blood plasma samples, respectively.