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A sensitive and effective micellar electrokinetic capillary chromatography with laser-induced fluorescence detection approach was described for the determination of low molecular-mass thiols using 1,3,5,7-tetramethyl-8-phenyl-(4-iodoacetamido) difluoroboradiaza- s-indacene as the labeling reagent. After precolumn derivatization, baseline separation of six thiol compounds including cysteine, glutathione, N-acetylcysteine, homocysteine, 6-mercaptopurine, and penicillamine were achieved within 18 min. The optimal running buffer was composed of mixtures involving 25 mM sodium dodecyl sulfate, 25% (v/v) acetonitrile and 15 mM sodium phosphate buffer, pH 7.5. The detection limits (S/N = 3) were found as low as 40 pM under argon ion laser-induced fluorescence detector ( λex/ λem = 488/520 nm), which were much better than the reported approaches. The accuracy and specificity of this assay for real samples were assured by a standard addition method. The proposed method has been applied to the analysis of thiols both in human plasma and plum flower samples with recoveries of 92.0-109.4%. [ABSTRACT FROM AUTHOR]

The soil bacterium Bacillus subtilis is widely used in agriculture as a biocontrol agent able to protect plants from a variety of pathogens. Protection is thought to involve the formation of bacterial communities - biofilms - on the roots of the plants. Here we used confocal microscopy to visualize biofilms on the surface of the roots of tomato seedlings and demonstrated that biofilm formation requires genes governing the production of the extracellular matrix that holds cells together. We further show that biofilm formation was dependent on the sensor histidine kinase KinD and in particular on an extracellular CACHE domain implicated in small molecule sensing. Finally, we report that exudates of tomato roots strongly stimulated biofilm formation ex planta and that an abundant small molecule in the exudates, L-malic acid, was able to stimulate biofilm formation at high concentrations in a manner that depended on the KinD CACHE domain. We propose that small signalling molecules released by the roots of tomato plants are directly or indirectly recognized by KinD, triggering biofilm formation. [ABSTRACT FROM AUTHOR]

The article offers information on the early mineralization age of the Hengjian uranium deposit, a typical hydrothermal deposit in the Xiangshan uranium ore field in China. It further discusses using the secondary ion mass spectrometry (SIMS) Uranium-Lead (U-Pb) method for analysis of zircon grains from the Hengjian granite porphyry; zircon grains examined with transmitted and reflected light and cathodoluminescence (CL) images; and use of the CAMECA IMS1280 ion microprobe.

Abstract: As a cell-specific organelle, acrosome (Acr) and its formation are an important event for spermiogenesis. However, the Acr formation is far more complicated than has been proposed. In this study, we have cloned a novel membrane protein Afaf (Acr formation associated factor) that was expressed abundantly in the round spermatids, localized in the inner and outer membrane of forming Acrs, and declined in the maturing Acrs. In the transfected Hela cells, Afaf protein was localized in the plasma membrane, EEA1-positive early endosomes (EEs) and occasionally in the nuclei. Therefore, we propose that EEs and plasma membrane may be also directly involved in the Acr biogenesis. [Copyright &y& Elsevier]

Abstract: Embryonic stem (ES) cells, derived from blastocyst-stage of early mammalian embryos, have the potential to differentiate into derivatives of all three embryonic germ layers. Here we reported the first evidence that murine pluripotent ES cells could be induced to differentiate into cardiomyocytes by cyclic adenosine 3′,5′-monophosphate (cAMP) in vitro. Spontaneously beating of cardiac cell clusters began to be observed within the outgrowths of embryoid bodies (EBs) as early as 2 days after the onset of differentiation. By days 5–8 after induction, a maximum level of cardiomyocyte differentiation could be achieved. Incubation of EBs with cAMP at concentrations ranging from 0.01mg/L to 1mg/L resulted in a significant elevation in differentiation rate, reaching a maximum value of 44.0±1.3% at 0.03mg/L of exposure. At 0.03mg/L concentration point, an approximately 8.1-fold increase in cardiomyocyte differentiation was observed in comparison with 5.4±0.9% of untreated controls. The differentiation rate induced by cAMP was shown to be similar to that of RA/DMSO treated controls, indicating that cAMP has the same inducing effect as RA/DMSO. However, no significant co-inducing effects between cAMP and RA/DMSO were seen. Cardiomyocytes were evident as they expressed cardiac cell specific genes and protein markers including GATA4, Nkx2.5, β-MHC, atrial natriuretic factor (ANF) and alpha-actin when analyzed by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemical staining. The results from the present study suggested a novel role of cAMP in cardiomyocyte differentiation and provided a new research model for the study of cardiac cell biology. [Copyright &y& Elsevier]

We have cloned, expressed and characterized a novel member of the human UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (pp-GalNAc-T) family, pp-GalNAc-T15. The pp-GalNAc-T15 transcript was ubiquitously expressed in human tissues. Recombinant pp-GalNAc-T15 transferred N-acetylgalactosamine (GalNAc) toward a panel of mucin-derived peptide substrates in vitro. Although pp-GalNAc-T15 showed significantly less catalytic activity than pp-GalNAc-T2, T15 transferred up to seven GalNAcs to the Muc5AC peptide, while T2 transferred up to five GalNAcs. These results clearly indicated that pp-GalNAc-T15 is a novel member of the human pp-GalNAc-T family with unique catalytic activity. [Copyright &y& Elsevier]

A novel member of the human UDP-N-acetyl-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (pp-GalNAc-T) gene family was cloned as a homolog of human pp-GalNAc-T7, and designated pp-GalNAc-T10. pp-GalNAc-T10 transcript was found in the small intestine, stomach, pancreas, ovary, thyroid gland and spleen. In a polypeptide GalNAc-transfer assay, recombinant pp-GalNAc-T10 transferred GalNAc onto a panel of mucin-derived peptide substrates. Furthermore, pp-GalNAc-T10 demonstrated strong transferase activity with glycopeptide substrates. [Copyright &y& Elsevier]

Metal–organic framework–derived carbon nanostructures have generated significant interest in electrochemical capacitors and oxygen/hydrogen catalysis reactions. However, they appear to show considerably varied structural properties, and thus exhibit complex electrochemical–activity relationships. Herein, a series of carbon polyhedrons of different sizes, between 50 nm and µm, are synthesized from zeolitic imidazolate frameworks, ZIF‐8 (ZIF‐derived carbon polyhedrons, ZDCPs) and their activity is studied for capacitance and the oxygen reduction reaction (ORR). Interestingly, a well‐correlated performance relationship with respect to the particle size of ZDCPs is evidenced. Here, the identical structural features, such as specific surface area (SSA), microporosity, and its distribution, nitrogen doping, and graphitization are all strictly maintained in the ZDCPs, thus allowing identification of the effect of particle size on electrochemical performance. Supercapacitors show a capacity enhancement of 50 F g−1 when the ZDCPs size is reduced from micrometers to ≤200 nm. The carbonization further shows a considerable effect on rate capacitance—ZDCPs of increased particle size lead to drastically reduced charge transportability and thus inhibit their performance for both the charge storage and the ORR. Guidelines for the capacitance variation with respect to the particle size and SSA in such carbon nanostructures from literature are presented. [ABSTRACT FROM AUTHOR]

A hybrid chemically and physically linked polyacrylamide (PAM)/carboxymethyl hydroxypropyl guar gum (CMHPG) system is prepared via a fast and controllable one‐pot strategy. Due to the synergetic effect of the non‐covalent interactions between chains, these systems show improved, balanced mechanical properties. The apparent morphology, storage modulus G′, and loss modulus G″ show that these systems have rapid and almost full recovery ability (the self‐healing efficiency can reach 95%) with several hydrogen‐bonding interactions between two networks. This self‐healing property can cover the shortage of G′, G″, and viscosity loss at high shear force, which will help the system keep enough viscosity to create fractures or carry proppants during the whole fracturing process. Meanwhile, the self‐healing fracturing fluid can be broken easily and flow back to surface with little damage to the fracture conductivity, indicating great potential in unconventional reservoir which is sensitive to the fracturing fluid damage. A hybrid chemically and physically linked polyacrylamide/carboxymethyl hydroxypropyl guar gum system is prepared via a fast and controllable one‐pot strategy. Due to the synergetic effect of the non‐covalent interactions between chains, these systems show improved and balanced mechanical properties and recovery ability, indicating great potential in unconventional reservoir stimulation. [ABSTRACT FROM AUTHOR]

The nonadiabatic holonomic quantum computation has attracted much attention in recent years because of its fastness and robustness. Here, the first scheme to realize theoretically universal single‐qubit gates on an optomechanical system working with nonadiabatic geometric phases is proposed. These quantum gates are robust to the control errors and parameter fluctuations. They can be used to achieve efficiently both quantum state transfer and entanglement generation between two optical modes via the intermediate action of a mechanical mode, showing that they are useful in robust quantum information processing. Universal single‐qubit gates are realized based on the nonadiabatic geometric dynamics of a double‐cavity optomechanical system when its cyclic evolution and parallel‐transport conditions are satisfied. These gates are fast and robust, and can also be used to achieve the quantum state transfer and the optical entanglement generation. [ABSTRACT FROM AUTHOR]

The article presents the case history of a 55-year-old man who had a falling accident, presented with acute back pain, numbness and tingling in the left leg because of lumbar burst fracture. Loss of height of the anterior vertebral body, fracture of the posterior wall or retropulsion of fracture fragments into the spinal canal characterize burst fractures.

Two four-membered bissilylene-linked bisamidines of type (V) are prepared from lithium complexes (I) obtained from primary amines in four steps. [ABSTRACT FROM AUTHOR]