Notes

Cortical hypometabolism reflects nearby atrophy and also tau pathology within pointing to Alzheimer's disease.
A molecule-based ferroelectric triethylmethylammonium tetrachloroferrate(III) ([N(C2H5)3CH3][FeCl4]) powder was designed as a multifunctional material exhibiting excellent multiple bistability. Prepared by the slow evaporation method at room temperature, the compound crystallizes in the non-centrosymmetric assembly of hexagonal symmetry (P63mc space group) which undergoes a reversible temperature-triggered phase transition pinpointed at 363 K to the centrosymmetric packing within the P63/mmc space group. Aside from the inseparable role of the symmetry-breaking process smoothly unveiled from the X-ray powder diffraction data, a striking change in the dielectric permittivity observed during the paraelectric-to-ferroelectric phase transition directly discloses the bistable dielectric behavior-an exceptionally high increase in the dielectric permittivity of about 360% at 100 kHz across the heating and cooling cycles is direct proof showing the highly desirable stimuli-responsive electric ordering in this improper ferroelectric architecture. Due to the magnetically modulated physical properties resulting in the coupling of magnetic and electric orderings, the flexible assembly of [N(C2H5)3CH3][FeCl4] could be used to boost the design and development of novel magnetoelectric devices.An efficient divergent synthetic strategy that leverages the natural product spectinomycin to access uniquely functional-ized monosaccharides is described. Stereoselective 2'- and 3'-reduction of key spectinomycin-derived intermediates ena-bled facile access to all eight possible 2,3-stereoisomers of 4,6-dideoxyhexoses as well as representative 3,4,6-trideoxysugars and 3,4,6-trideoxy-3-aminohexoses. In addition, the method was applied to the synthesis of two function-alized sugars commonly associated with macrolide antibiotics - the 3-O-alkyl-4,6-dideoxysugar D-chalcose and the 3-N-alkyl-3,4,6-trideoxysugar D-desosamine.The incorporation of molecular switches in organic structures is of great interest in the chemical design of stimuli-responsive materials that mimic the complex functions of living systems. Merocyanine dyes that convert to spiropyran moieties upon exposure to visible light have been extensively studied as they can be incorporated in hydrated covalent networks that will expel water when this conversion occurs and induce a volumetric shrinkage. We report here on a sulfonate-based water-soluble photoswitch that, in contrast to the well-known systems, triggers a volumetric expansion in hydrogels upon exposure to photons. Contraction is in turn observed under dark conditions in a highly reversible manner. The novel behavior of the photoswitch incorporated in the covalent network was predicted by coarse-grained simulations of the system's chemical structure. Using pH control and polymeric structures that differ in lower critical solution temperature, we were able to develop hydrogels with highly tunable volumetric expansion. The novel molecular function of the systems developed here led to materials with the negative phototaxis observed in plants and could expand the potential use of hydrogels as sensors, soft robots, and actuators.Glyphosate is the most used herbicide on the planet because of its excellent efficacy on almost all weeds species and due to the large-scale adoption of transgenic, glyphosate-resistant (GR) crops. Agnes Rimando became an expert in glyphosate analysis almost 20 years ago to support research on GR crop safety and on mechanisms of evolved glyphosate resistance by weeds. Her work was the first to show that the amount of glyphosate and its primary metabolite aminomethylphosphonic acid (AMPA) that accumulates in GR soybean seed from plants treated with approved glyphosate doses can approach their legal limits. However, she later found that the only trace amounts of these compounds accumulate in seed of GR maize treated with recommended glyphosate doses. She showed that GR canola, the only transgenic crop with a transgene encoding an enzyme for degradation of glyphosate, metabolizes glyphosate to AMPA very rapidly. Her work was instrumental in providing support for the view that "yellow flash" symptoms sometimes observed in field-grown GR soybeans are due to accumulation of enough AMPA to cause mild phytotoxicity. She did the chemical analyses in the only paper to survey the capacity of an array of plant species to metabolize glyphosate to AMPA. She found a wide range in this capacity, with grasses with little or no metabolism of glyphosate to AMPA and with legumes readily metabolizing glyphosate. Lastly, she found no evidence of enhanced degradation of glyphosate to be a mechanism of evolved resistance to glyphosate by two weed species, but that it might be involved in natural tolerance to glyphosate of some weeds.Novel pyrimidine sulfide derivatives containing dithioacetal and strobilurin moiety were designed and synthesized. Their antiviral activities against tomato chlorosis virus (ToCV) were investigated through the ToCVCP-oriented screening method. Microscale thermophoresis (MST) was used to study the interaction between the compound and the tomato chlorosis virus coat protein (ToCVCP). Compounds B13 and B23 interacted better with ToCVCP than other compounds and had dissociation constant (Kd) values of 0.09 and 0.06 μM, respectively. These values were lower than those of the control agent ningnanmycin (0.19 μM) and ribavirin (6.54 μM), which indicated that the compounds had a strong binding effect with ToCVCP. Quantitative real-time PCR (qRT-PCR) was used to evaluate the role of compounds B13 and B23 in the gene regulation of ToCVCP. Both compounds significantly reduced the expression level of ToCVCP gene in Nicotiana benthamiana with reduction values of 88% and 83%, which were better than those of ningnanmycin (65%) and lead compound C14 (73%). Pyrimidine sulfide containing a dithioacetal and strobilurin moiety is significant in the research and development of novel anti-ToCV agents.To aid the development of novel antibacterial agents that possess a novel mechanism of action, we used myricitrin as the raw material to build a series of novel dithiocarbamate-containing 4H-chromen-4-one derivatives. The derivatives were evaluated via turbidimetry tests and screened against three plant pathogens Xanthomonas oryzae pv.oryzae (X. oryzae pv. o.), Ralstonia solanacearum (R. solanacearum), and Xanthomonas axonopodis pv. Citri (X. axonopodis pv. c). Antibacterial-bioassay results revealed that the target compounds displayed good inhibitory effects against X. oryzae pv. o. and X. axonopodis pv. c. In particular, compound E6 exhibited the best in vitro antibacterial activities against X. axonopodis pv. c, with EC50 values of 0.11 µg/mL, which were better than those of thiodiazole copper (59.97 µg/mL) and bismerthiazol (48.93 µg/mL). Compound E14 exhibited the best in vitro antibacterial activities against X. oryzae pv. o., with EC50 values of 1.58 µg/mL, which were better than those of thiodiazole copper (83.04 µg/mL) and bismerthiazol (56.05 µg/mL). Scanning electron microscopy analysis indicated that compounds E6 and E14 caused the cell membranes of X. axonopodis pv. c and X. oryzae pv. o. broken or deformed, respectively. In vivo antibacterial activity test and the defensive enzymes activity test results indicated that the compound E14 could reduce X. oryzae pv. o. more effectively than thiodiazole-copper or bismerthiazol.CpG methylation of DNA is common in mammalian cells. In sperms, the DNA has the highest level of CpG methylation and is condensed into toroidal structures. How CpG methylation affects DNA structures and interactions is important to understand its biological roles but is largely unknown. Using an RNA-DNA-RNA structure, we observed the equilibrium hopping dynamics between the condensed and extended states of DNA in the pres-ence of polyamines or polylysine peptide as a reduced model of histone tails. Combing with the measured DNA elasticities, we report that CpG methylation of each cytosine nucleotide substan-tially increases DNA-DNA attraction by up to 0.2 kBT. For the DNA with 57% GC content, the relative increase caused by CpG methylation is up to 32% for the spermine-induced DNA-DNA attraction and up to 9% for the polylysine-induced DNA-DNA attraction. These findings help us to evaluate the energetic con-tributions of CpG methylation in sperm development and chro-matin regulation.Cellulose nanocrystals (CNCs), having a high specific surface area and versatile surface chemistry, provide a considerable potential to interact by various mechanisms with enzymes for nano-immobilization purposes. Yet, engineering chemically safe CNCs, suitable for edible administrations, presents a significant challenge. A reliable carboxylate form of H-CNCs was formed using H2O2 oxidation of softwood pulp under mild thermal condition. Selleckchem AZD9291 Negatively charged carboxyl groups (~0.9 mmol g-1) played a key role in lysozyme immobilization via electrostatic interactions and covalent linkages, as evidenced by FT-IR and 13C CP-MAS NMR spectroscopies. Adsorption isotherms showed a high loading capacity of H-CNCs (~240 mg g-1), and fitting the data to the Langmuir model, confirmed monolayer coverage of lysozymes on their surface. Using a non-toxic coupling agent, DMTMM, lysozyme-conjugated H-CNCs were developed with an immobilization yield of ~65% and relative catalytic activity of ~60%, similarly to lysozyme adsorption on H-CNCs. These H-CNC-lysozyme nanohybrids, rationally processed via safe and green strategies, are specifically exploitable as catalytically active emulsifiers in food and pharmaceutical sectors.Measurements of land-air mercury (Hg) exchanges over vegetated surfaces are needed to further constrain Hg fluxes over vegetated terrestrial surfaces. Yet, knowledge of land-air Hg dynamics in alpine grasslands remains poor. Hg fluxes over an alpine meadow were measured throughout a full vegetation period in the central Tibetan Plateau (TP). This TP grassland served as a small source of atmospheric total gaseous Hg (TGM) during vegetation period (0.92 μg m-2). Hg fluxes decreased logarithmically during plant growing season, resulting from the influence of vegetation by light shading and plant Hg uptake, although the latter might be minor due to low biomass at this site. Temporal patterns of TGM indicated the importance of land-air dynamics in regulating TGM levels. During the plant emergence, diel pattern of TGM covaried with Hg emission fluxes resulting in lower concentrations at night and higher concentrations in afternoon. During all other vegetation stages, TGM showed minima before dawn and "morning peak" shortly after sunrise, in conjunction with corresponding Hg fluxes showing sink before dawn and source after sunrise. Moreover, TGM concentrations showed a decreasing trend with plant growing, further indicating the role of vegetation in driving seasonal TGM variations by regulating land-air Hg dynamics.With the trigonal linker 4,4',4″-s-triazine-2,4,6-triyltribenzoic acid as a building block, porous cobalt metal-organic frameworks (named as PCN) have been successfully prepared and directly utilized as active materials in alkaline battery-type devices. For comparison, their carbon-supported hybrids (CNFs/PCN) have also been employed as battery-type electrodes. We found that the pristine PCN displayed a better performance than the CNFs/PCN composite electrode in electrochemical cells. To further investigate their electrochemical performances, alkaline battery-supercapacitor hybrid (BSH) devices with these materials as positive electrodes and activated carbon (AC) as the negative electrode were fabricated. The results indicate that the PCN//AC BSH devices delivered a maximum energy density of 16.0 Wh kg-1 at a power density of 749 W kg-1 within the voltage range of 0-1.5 V, which are much higher than those of CNFs/PCN//AC devices (12.4 Wh kg-1 at 753 W kg-1).
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