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2 chemoattenuated PfSPZ malaria vaccines cause sterile and clean hepatic immunity.
Isolated hafnium (Hf) sites were prepared on Silicalite-1 and SiO2 and investigated for acetone conversion to isobutene. Characterization by IR, 1H MAS NMR, and UV-vis spectroscopy suggests that Hf atoms are bonded to the support via three O atoms and have one hydroxyl group, i.e, (≡SiO)3Hf-OH. In the case of Hf/Silicalite-1, Hf-OH groups hydrogen bond with adjacent Si-OH to form (≡SiO)3Hf-OH···HO-Si≡ complexes. The turnover frequency for isobutene formation from acetone is 4.5 times faster over Hf/Silicalite-1 than Hf/SiO2. Lewis acidic Hf sites promote the aldol condensation of acetone to produce mesityl oxide (MO), which is the precursor to isobutene. For Hf/SiO2, both Hf sites and Si-OH groups are responsible for the decomposition of MO to isobutene and acetic acid, whereas for Hf/Silicalite-1, the (≡SiO)3Hf-OH···HO-Si≡ complex is the active site. Measured reaction kinetics show that the rate of isobutene formation over Hf/SiO2 and Hf/Silicalite-1 is nearly second order in acetone partial pressure, suggesting that the rate-limiting step involves formation of the C-C bond between two acetone molecules. The rate expression for isobutene formation predicts a second order dependence in acetone partial pressure at low partial pressures and a decrease in order with increasing acetone partial pressure, in good agreement with experimental observation. The apparent activation energy for isobutene formation from acetone over Hf/SiO2 is 116.3 kJ/mol, while that for Hf/Silicalite-1 is 79.5 kJ/mol. The lower activation energy for Hf/Silicalite-1 is attributed to enhanced adsorption of acetone and formation of a C-C bond favored by the H-bonding interaction between Hf-OH and an adjacent Si-OH group.Electrochemical conversion of CO2 into valuable products is a promising approach. Efficient electrocatalysts are highly desirable but remain to be developed. Here, we proposed a molecular encapsulation strategy to enrich intermediates for facilitating electrochemical conversion of CO2 to C2H4. This strategy is combining M-TCPP [M = FeCl, Co, and Ni; TCPP = tetrakis(4-carboxyphenyl) porphyrin] with a Cu-based metal-organic framework (Cu-MOF) to create a series of metalloporphyrin-decorated Cu catalysts with a coral-like shape (named as M-TCPP@Cu). M-TCPP in the catalysts could supply more CO intermediates to the Cu sites, giving high selectivity for producing C2H4 and lowering overpotentials for CO2 reduction. Meanwhile, the coral-like structure of the catalyst with abundant active sites is conducive to mass diffusion and benefits the conversion of CO2. We realized a higher C2H4 Faradaic efficiency (FE) of 33.42% at -1.17 V versus reversible hydrogen electrode (RHE) on the Fe-TCPP@Cu electrode than that on the sole Cu electrode (16.85%, at -1.27 V vs RHE). Furthermore, due to the encapsulated structure resulted from one-pot reaction that ensures the dispersion of active centers in M-TCPP, metalloporphyrin-decorated Cu catalysts show better performance than the physical mixture of Cu-MOFs and M-TPPs (M = FeCl, Co, and Ni; TPP = 5,10,15,20-tetraphenylporphyrin). The results provide a new strategy for the design of high-performance Cu catalysts from Cu-MOFs for CO2 conversion.Isothermal nucleic acid amplification strategies have been combined with nanotechnology for advanced biosensing, material design, and biomedical applications. However, merging phenomena and materials of different nanoscales with the aim of exploiting all their benefits at once has remained a challenging endeavor. Here, we exemplify the various problems one can encounter when combining the nanodimensions of lanthanide complexes (∼2 nm), Förster resonance energy transfer (FRET, ∼5 nm), quantum dots (QDs, ∼20 nm), and rolling circle amplification (RCA, ∼250 nm) into a single microRNA biosensor and how these challenges can be overcome. Six different approaches, including simple FRET-RCA, enzyme-digesting FRET-RCA, and FRET-hyperbranched-RCA were investigated. We demonstrated specific miR-21 detection with 80 fM limit of detection and multiplexing capability with FRET from a Tb complex to different QDs. The detailed view on the various complex multi-nanodimensional assay systems elucidated the limited clinical translation of such sophisticated multicomponent nanobiosensors.The use of vanadyl porphyrins either in synthetic compounds or naturally occurring in asphaltenes is investigated as a source of proton hyperpolarization via dynamic nuclear polarization (DNP) in nuclear magnetic resonance (NMR) experiments. The features of dynamics and location of the vanadyl VO2+ complex in aggregates within the oil asphaltene molecules are studied by means of DNP, electron paramagnetic resonance (EPR), and NMR field cycling relaxometry. Both the solid effect and Overhauser DNP were observed for the asphaltene solution in benzene, as well as in the solution and solid states for synthetic compounds. By comparison with a solution of synthetic vanadyl porphyrins, it is shown that vanadyl porphyrins in asphaltene aggregates are localized outside of the interface of the asphaltene aggregates and more exposed to the maltene molecules than "free" carbon-centered radicals associated with the core of asphaltene molecules. The perceptible contribution of scalar interaction is observed in solutions for both synthetic and asphaltene vanadyl porphyrins.Jet propulsion 10 (JP-10) droplets with and without aluminum nanoparticles in conjunction with HZSM-5 zeolite and surfactants were ultrasonically levitated, and their oxidation processes were explored to identify how the oxidation process of JP-10 is catalytically affected by the HZSM-5 zeolites and how the surfactant and Al NPs in the system impacted the key experimental parameters of the ignition such as ignition delay time, burn rate, and the maximum temperatures. Singly levitated droplets were ignited using a carbon dioxide laser under an oxygen-argon atmosphere. Pure JP-10 droplets and JP-10 droplets with silicon dioxide of an identical size distribution as the zeolite HZSM-5 did not ignite in strong contrast to HZSM-5-doped droplets. Acidic sites were found to be critical in the ignition of the JP-10. With the addition of the surfactant, the characteristic features of the JP-10 ignition were improved, so the ignition delay time of the zeolite-JP-10 samples were decreased by 2-3 ms and the burn rates were increased by 1.3 to 1.6 × 105 K s-1. The addition of Al NPs increased the maximum temperatures during the combustion of the systems by 300-400 K. Intermediates and end products of the JP-10 oxidation over HZSM-5 were characterized by UV-vis emission and Fourier-transform infrared transmission spectroscopies, revealing key reactive intermediates (OH, CH, C2, O2, and HCO) along with the H2O molecules in highly excited rovibrational states. Sodium hydroxide ic50 Overall, this work revealed that acetic sites in HZSM-5 are critical in the catalytic ignition of JP-10 droplets with the addition of the surfactant and Al NPs, enhancing the oxidation process of JP-10 over HZSM-5 zeolites.Dielectric nanostructures have demonstrated optical antenna effects due to Mie resonances. Previous work has exhibited enhancements in absorption, emission rates and directionality with practical limitations. In this paper, we present a Si mix antenna array to achieve a trifecta enhancement of ∼1200-fold with a Purcell factor of ∼47. The antenna design incorporates ∼10 nm gaps, within which fluorescent molecules strongly absorb the pump laser energy through a resonant mode. In the emission process, the antenna array increases the radiative decay rates of the fluorescence molecules via a Purcell effect and provides directional emission through a separate mode. This work could lead to novel CMOS-compatible platforms to enhance fluorescence for biological and chemical applications.Seven nitrosamines and three nitramines in particulate matter with an aerodynamic diameter of less than or equal to 2.5 μm (PM2.5) collected in 2018 in Seoul, South Korea, were quantified. Annual mean concentrations of the sum of nitrosamines and nitramines were 9.81 ± 18.51 and 1.12 ± 0.70 ng/m3, respectively, and nitrosodi-methylamine (NDMA) and dimethyl-nitramine (DMN) comprised the largest portion of nitrosamines and nitramines, respectively. Statistical analyses such as non-parametric correlation analysis, positive matrix factorization, analysis of covariance, and orthogonal partial least squared discrimination analysis were carried out to identify contribution of the atmospheric reactions in producing NDMA and DMN. In addition, kinetic calculation using reaction information obtained from the previous chamber studies was performed to estimate concentrations of NDMA and DMN that might be produced from the atmospheric reactions. It was concluded that (1) the atmospheric reactions contributed to the concentrations of NDMA more than they did for those of DMN, (2) the contribution of atmospheric reactions to the concentrations of NDMA and DMN was significant due to high NO2 concentrations in winter, and (3) primary emissions predominantly affected the ambient concentrations of NDMA and DMN in spring, summer, and autumn.Six arsenic(III)-capped 12-tungsto-2-arsenates(III) of the type [M2(AsIIIW6O25)2(AsIIIOH)x]n- (M = CrIII, 1; FeIII, 2; ScIII, 3; InIII, 4; TiIV, 5; MnII, 6) have been synthesized in aqueous medium by direct reaction of the elements using a one-pot strategy and structurally characterized by FT-IR spectroscopy, single-crystal XRD, and elemental analysis. Polyanions 1-6 are comprised of two octahedrally coordinated guest metal ions M sandwiched between two AsW6 units, resulting in a structure with C2h point-group symmetry. Polyanions 1-5 contain tri- and tetravalent metal ion guests M (M = CrIII, FeIII, ScIII, InIII, and TiIV, respectively), and they have one AsIIIOH group grafted on each AsW6 unit, whereas the divalent MnII-containing derivative 6 has two such AsIIIOH groups grafted on each AsW6 unit. Magnetic studies on polyanions 3-5 over the temperature range 1.8-295 K and magnetic fields of 0-7 T confirmed that they are diamagnetic. On the other hand, polyanions 1, 2, and 6 are strongly magnetic and follow the Curie-Weiss law above 30 K. The susceptibility plots of 1 and 6 exhibit broad peaks suggesting short-range antiferromagnetic ordering, while the very weak antiferromagnetic ordering of 2 is overshadowed by traces of a paramagnetic impurity. The magnetization data of 1, 2, and 6 at 1.8 K over 0-7 T were analyzed by using the Heisenberg exchange procedure. Small (negative) values of the obtained J values help in understanding the absence of long-range antiferromagnetic ordering.Reliance on bioremediation to remove benzene from anoxic environments has proven risky for decades but for unknown reasons. Research has revealed a strong link between anaerobic benzene biodegradation and the enrichment of highly specific microbes, including Thermincola in the family Peptococcaceae and the deltaproteobacterial Candidate Sva0485 clade. Using aquifer materials from Canadian Forces Base Borden, we compared five bioremediation approaches in batch microcosms. Under conditions simulating natural attenuation or sulfate biostimulation, benzene was not degraded after 1-2 years of incubation and no enrichment of known benzene-degrading microbes occurred. In contrast, nitrate-amended microcosms reported benzene biodegradation coincident with significant growth of Thermincola spp., along with a functional gene presumed to catalyze anaerobic benzene carboxylation (abcA). Inoculation with 2.5% of a methanogenic benzene-degrading consortium containing Sva0485 (Deltaproteobacteria ORM2) resulted in benzene biodegradation in the presence of sulfate or under methanogenic conditions.
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