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Bacterial surface glycans perform a diverse and important set of biological roles, and have been widely used in the treatment of bacterial infectious diseases. The majority of bacterial surface glycans are decorated with diverse rare functional groups, including amido, acetamidino, carboxamido and pyruvate groups. These functional groups are thought to be important constituents for the biological activities of glycans. Chemical synthesis of glycans bearing these functional groups or their variants is essential for the investigation of structure-activity relationships by a medicinal chemistry approach. To date, a broad choice of synthetic methods is available for targeting the different rare functional groups in bacterial surface glycans. This article reviews the structures of naturally occurring rare functional groups in bacterial surface glycans, and the chemical methods used for installation of these groups.

D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined D-allose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The Lattrell-Dax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated SN1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido (TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the Lattrell-Dax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.

Three novel entangled coordination polymers (CPs), namely, [Cu4(BPB)5(HPW12O40)2]·2H2O (JOU-15), [Cu3(BPB)3PW12O40] (JOU-16), and [Cu3(BPBP)3PW12O40] (JOU-17), have been successfully synthesized by combining flexible N-donor ligands and Keggin type polyoxometalates with copper ion under hydrothermal conditions. Structural characterizations show that JOU-15 features an unusual 1D + 1D → 2D entangled network with the coexistence of polycatenation and interdigitation. JOU-16 exhibits a fascinating self-catenated three-dimensional framework with a new point symbol of (44·610·8)(65·8)(66). JOU-17 displays a novel 1D + 3D + 3D → 3D entangled framework with features of both polycatenation and polythreading. In addition, the electrochemical properties of these compounds have also been studied.

Background: Evidence for the effect of dietary sodium intake on the risk of cardiovascular disease has been controversial. One of the main explanations for the conflicting results lies in the great variability associated with measurement methods for sodium intake. Spot urine collection is a convenient method commonly used for sodium estimation, but its validity for predicting 24-h urinary sodium excretion at the individual level has not been well evaluated among the general population.Objective: The aim of this study was to evaluate the validity of the Kawasaki, the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT), and the Tanaka formulas in predicting 24-h urinary sodium excretion by using spot urine samples in Chinese adults.Design: We analyzed the relative and absolute differences and misclassification at the individual level from 3 commonly used methods for estimating sodium intake among 141 Chinese community residents.Results: The mean measured 24-h sodium excretion was 220.8 mmol/d. The median (95% CIs) differences between measured sodium and those estimated from the Kawasaki, INTERSALT, and Tanaka methods were 6.4 mmol/d (-17.5, 36.8 mmol/d), -67.3 mmol/d (-96.5, -46.9 mmol/d), and -42.9 mmol/d (-59.1, -24.8 mmol/d), respectively. The proportions of relative differences >40% with the Kawasaki, INTERSALT, and Tanaka methods were 31.2%, 41.1%, and 22.0%, respectively; and the absolute difference for the 3 methods was >51.3 mmol/d (3 g salt) in approximately half of the participants. The misclassification rate was 63.1% for the Kawasaki method, 78.7% for the INTERSALT method, and 66.0% for the Tanaka method at the individual level.Conclusion: The results from our study do not support the use of spot urine to estimate 24-h urinary sodium excretion at the individual level because of its poor performance with respect to misclassification. This trial was registered at www.chictr.org.cn as ChiCTR-IOR-16010278.

Maize female organs are sensitive to drought stress, leading to reproductive failure and yield reduction. In the present study gene expression profiles of ears and silks of maize at the flowering stage under drought stress were investigated. From 1920 white positive clones of a forward suppression subtractive hybridization (SSH) library, 1439 available sequences of expression sequence tags (ESTs) were obtained, resulting in 361 unique ESTs after assembling. Data analysis showed that 218 of the unique ESTs had significant protein homology by BLASTX in UNIPROT database. Totally 99 uniESTs were found in TIGR maize gene indices and nr database by BLASTN, while 44 uniESTs were not found to have homologous nucleic acid sequences and putatively classified as "maize-specific" uniESTs. The 218 cDNAs with significant protein homology were sorted into 13 groups according to the functional categories of the Arabidopsis proteins. Among those genes, the genes associated with the metabolisms were the largest group (account for 27%), and the genes related to protein synthesis, protein fate, transcription, cell cycle and DNA processing accounted for 16, 10, 10 and 9%, respectively. After analysis of macroarray data and real-time quantitative polymerase chain reaction (PCR), it was found that 160 of the 218 homologous protein uniESTs were up-regulated genes in the ears, 129 in the silks, and 125 in both of the tissues. The present work provided a valuable starting point for further elucidation of the roles played by these genes/gene products in drought tolerance in maize.

A hydrophilic polymer, poly(N-vinyl-2-pyrrolidone), was tethered on the surface of polypropylene microfiltration membrane (PPMM) by UV photo-assisted and γ-ray pre-irradiation induced graft polymerizations. Results revealed that the γ-ray pre-irradiation graft polymerization was more efficient in view of the grafting degree. The chemical changes of the membrane surface were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Pure water contact angle on poly(N-vinyl-2-pyrrolidone)-grafted PPMM decreased with the increase of grafting degree, which indicated an enhanced hydrophilicity for the modified membrane. Both bovine serum albumin adsorption and static platelets adhesion were measured to evaluate the bio-compatibility of the poly(N-vinyl-2-pyrrolidone)-modified PPMM. The statistical amounts of adsorbed bovine serum albumin and adhered platelets on unit membrane area decreased significantly, which to a certain degree demonstrated that the hemocompatibility of PPMM was improved. The N2 permeability and the mean pore diameters of different PPMMs increased at first, then decreased after certain grafting degree. The changes of water flux followed a similar tendency. These indicated that at low grafting degree pore degradation induced by γ-ray irradiation had a major impact on permeability, while this was overcompensated by the grafted polymer at high grafting degrees.

The steady state stability limit of turbine generator with automatic voltage regulator (AVR) extends steam turbine's safe range under exciting operation compared to generator without AVR. Therefore, Paper analyzes the parameter of AVR's effect on steady state stability limit of turbine generator, and verifies the conclusion with the simulation model in Matlab/Simulink environment.

Carbon nano onions (CNOs) with diameters of 70–100 nm were fabricated by chemical vapor deposition at 800 °C, using methane as carbon source and high-temperature steam treated 316 stainless steel mesh as catalyst. The CNOs were isolated from the substrate by HNO3 refluxing, calcination in air at 500 °C and magnetic separation. The morphology, microstructures and magnetic properties of the CNOs were characterized by SEM, TEM, XRD, Raman spectroscopy, FT-IR spectroscopy and vibration sample magnetometer tests. Results showed that the surface-attached catalyst particles and amorphous carbon can be effectively removed from raw CNOs through HNO3-refluxing and calcination. Magnetic separation can selectively remove the CNOs encapsulating a [Ni, Fe] magnetic catalyst from the CNOs that are hollow. [New Carbon Materials 2014, 29(5): 398–403]