Strong covalent bonds were in situ constructed in a unique black phosphorus (BP) @ reduced graphene oxide nanocomposite via a facile and scalable high energy ball-milling process, which contributes to the high specific capacity of BP@irGO and tackles the long-standing problem of large volume expansion of high capacity electrode matrerials.Novel bioinorganic hybrid materials based on proteins and inorganic clusters have enormous potential for the development of hybrid catalysts that synergistically combine properties of both materials. Here we report the creation of hybrid assemblies between a computationally designed symmetrical protein Pizza6-S and different polyoxometalates with matching symmetry the tellurotungstic Anderson-Evans (Na6[TeW6O24]·22H2O) (TEW); Keggin (H4[SiW12O40]·6H2O) (STA); and 1 2 CeIII-substituted Keggin (K11[CeIII[PW11O39]2]·20H2O) (Ce-K). This results in the formation of complexes with clearly defined stoichiometries in solution. Crystal structures validate the complexes as building blocks for the formation of larger assemblies.Miniaturization of electrochemical detection methods for point-of-care-devices is ideal for their integration and use within healthcare environments. Simultaneously, the prolific pathogenic bacteria Pseudomonas aeruginosa poses a serious health risk to patients with compromised immune systems. Recognizing these two factors, a proof-of-concept electrochemical method employing a micro-interface between water and oil (w/o) held at the tip of a pulled borosilicate glass capillary is presented. This method targets small molecules produced by P. aeruginosa colonies as signalling factors that control colony growth in a pseudo-multicellular process known as quorum sensing (QS). The QS molecules of interest are 4-hydroxy-2-heptylquinoline (HHQ) and 2-heptyl-3,4-dihydroxyquinoline (PQS, Pseudomonas quinolone signal). Hydrophobic HHQ and PQS molecules, dissolved in the oil phase, were observed electrochemically to facilitate proton transfer across the w/o interface. This interfacial complexation can be exploited as a facile electrochemical detection method for P. aeruginosa and is advantageous as it does not depend on the redox activity of HHQ/PQS. Interestingly, the limit-of-linearity is reached as [H+] ≈ [ligand]. Density functional theory calculations were performed to determine the proton affinities and gas-phase basicities of HHQ/PQS, as well as elucidate the likely site of stepwise protonation within each molecule.Semiconductor-liquid interfaces are essential to the operation of many energy devices. Crucially, the operational characteristics of such devices are dependent upon both the flat band potential and doping concentration present in their solid-state semiconducting region. Traditionally, capacitive "linear" Mott-Schottky plots have often been utilized to extract these two parameters. However, significant concentrations of surface states within semiconductor-liquid junctions can give rise to strong non-linearities that prevent an effective linearity-based analysis. In this work, we detail a theoretical approach for estimating both the doping concentration and flat band potential from the capacitive characteristics of semiconductor-liquid junctions heavily impacted upon by surface states. https://www.selleckchem.com/products/stat3-in-1.html Our theoretical approach is applied to CuGaS2 immersed in an aqueous electrolyte, for which excellent convergent values of the doping concentration and flat band potential are obtained across a wide range of impedance measurement frequencies. The results suggest a marked improvement over a linearity-based approach that could assist the analysis of many types of semiconductor-liquid junctions subject to high concentrations of surface states.The unsaturated metalloid germanium cluster Ge6N(SiMe3)Dipp42 with two ligand-free germanium atoms and only four amine substituents was obtained starting from the base-coordinated germylene N(SiMe3)DippGeCl·DMAP 1 in 50% yield (DMAP = 4-(dimethylamino)-pyridine). This cluster reacts as a masked digermyne in cycloadditions with ethylene, diphenylacetylene and 2,3-dimethyl-1,3-butadiene in toluene at 100 °C to yield 3-5.MicroRNAs (miRNAs) play an important role in various biological processes and have been regarded as promising diagnostic biomarkers for solid tumors in the field of clinical diagnostics. In this study, we developed a simple label/quencher-free fluorometric system for sensitive and selective miRNA detection using isothermal gene amplification such as rolling circle amplification generating tandem G-quadruplex DNA structures (GQ-RCA). The closed-circular dumbbell-shaped padlock DNA was designed to be complementary to its corresponding target miRNA. In the presence of the target miRNA, a long stretch of ssDNA with tandem G-quadruplex sequence repeats was readily generated by RCA, initiated by phi29 DNA polymerase through DNA synthesis priming at the 3'-OH of the target miRNA annealed to the padlock DNA. The RCA product harboring tandem G-quadruplex was monitored with fluorophore Thioflavin T (ThT) that emits strong fluorescence only when it intercalates into the G-quadruplex. The GQ-RCA assay enabled us to detect miRNA as low as 4.9 fM with a linear range from 25.6 fM to 80 pM within 0.5 h. In addition, our system was applied to the miRNA samples present in human plasma, showing its potential use in the clinical diagnosis of cancer.The presence of contaminants of emerging concern (CECs) in wastewater effluent and surface waters is an important field of research for analytical scientists. This study takes a suspect screening approach to wastewater and surface water analysis using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOFMS). Two extraction procedures, traditional liquid-liquid extraction (LLE) and stir bar sorptive extraction (SBSE), were utilized and evaluated for their application to wastewater and surface water samples. Both techniques were evaluated regarding their recovery rates, range of compound classes extracted, and on their application to discovery of CECs. For the 14 surrogate compounds analyzed, LLE was able to extract all of them in each matrix with a recovery range of 19% to 159% and a median value of 74%. For SBSE, the recovery rates ranged from 19% to 117% with the median value at 66%, but only 8 of the compounds were able to be extracted because of the polarity bias for this extraction method.
Strong covalent bonds were in situ constructed in a unique black phosphorus (BP) @ reduced graphene oxide nanocomposite via a facile and scalable high energy ball-milling process, which contributes to the high specific capacity of BP@irGO and tackles the long-standing problem of large volume expansion of high capacity electrode matrerials.Novel bioinorganic hybrid materials based on proteins and inorganic clusters have enormous potential for the development of hybrid catalysts that synergistically combine properties of both materials. Here we report the creation of hybrid assemblies between a computationally designed symmetrical protein Pizza6-S and different polyoxometalates with matching symmetry the tellurotungstic Anderson-Evans (Na6[TeW6O24]·22H2O) (TEW); Keggin (H4[SiW12O40]·6H2O) (STA); and 1 2 CeIII-substituted Keggin (K11[CeIII[PW11O39]2]·20H2O) (Ce-K). This results in the formation of complexes with clearly defined stoichiometries in solution. Crystal structures validate the complexes as building blocks for the formation of larger assemblies.Miniaturization of electrochemical detection methods for point-of-care-devices is ideal for their integration and use within healthcare environments. Simultaneously, the prolific pathogenic bacteria Pseudomonas aeruginosa poses a serious health risk to patients with compromised immune systems. Recognizing these two factors, a proof-of-concept electrochemical method employing a micro-interface between water and oil (w/o) held at the tip of a pulled borosilicate glass capillary is presented. This method targets small molecules produced by P. aeruginosa colonies as signalling factors that control colony growth in a pseudo-multicellular process known as quorum sensing (QS). The QS molecules of interest are 4-hydroxy-2-heptylquinoline (HHQ) and 2-heptyl-3,4-dihydroxyquinoline (PQS, Pseudomonas quinolone signal). Hydrophobic HHQ and PQS molecules, dissolved in the oil phase, were observed electrochemically to facilitate proton transfer across the w/o interface. This interfacial complexation can be exploited as a facile electrochemical detection method for P. aeruginosa and is advantageous as it does not depend on the redox activity of HHQ/PQS. Interestingly, the limit-of-linearity is reached as [H+] ≈ [ligand]. Density functional theory calculations were performed to determine the proton affinities and gas-phase basicities of HHQ/PQS, as well as elucidate the likely site of stepwise protonation within each molecule.Semiconductor-liquid interfaces are essential to the operation of many energy devices. Crucially, the operational characteristics of such devices are dependent upon both the flat band potential and doping concentration present in their solid-state semiconducting region. Traditionally, capacitive "linear" Mott-Schottky plots have often been utilized to extract these two parameters. However, significant concentrations of surface states within semiconductor-liquid junctions can give rise to strong non-linearities that prevent an effective linearity-based analysis. In this work, we detail a theoretical approach for estimating both the doping concentration and flat band potential from the capacitive characteristics of semiconductor-liquid junctions heavily impacted upon by surface states. https://www.selleckchem.com/products/stat3-in-1.html Our theoretical approach is applied to CuGaS2 immersed in an aqueous electrolyte, for which excellent convergent values of the doping concentration and flat band potential are obtained across a wide range of impedance measurement frequencies. The results suggest a marked improvement over a linearity-based approach that could assist the analysis of many types of semiconductor-liquid junctions subject to high concentrations of surface states.The unsaturated metalloid germanium cluster Ge6N(SiMe3)Dipp42 with two ligand-free germanium atoms and only four amine substituents was obtained starting from the base-coordinated germylene N(SiMe3)DippGeCl·DMAP 1 in 50% yield (DMAP = 4-(dimethylamino)-pyridine). This cluster reacts as a masked digermyne in cycloadditions with ethylene, diphenylacetylene and 2,3-dimethyl-1,3-butadiene in toluene at 100 °C to yield 3-5.MicroRNAs (miRNAs) play an important role in various biological processes and have been regarded as promising diagnostic biomarkers for solid tumors in the field of clinical diagnostics. In this study, we developed a simple label/quencher-free fluorometric system for sensitive and selective miRNA detection using isothermal gene amplification such as rolling circle amplification generating tandem G-quadruplex DNA structures (GQ-RCA). The closed-circular dumbbell-shaped padlock DNA was designed to be complementary to its corresponding target miRNA. In the presence of the target miRNA, a long stretch of ssDNA with tandem G-quadruplex sequence repeats was readily generated by RCA, initiated by phi29 DNA polymerase through DNA synthesis priming at the 3'-OH of the target miRNA annealed to the padlock DNA. The RCA product harboring tandem G-quadruplex was monitored with fluorophore Thioflavin T (ThT) that emits strong fluorescence only when it intercalates into the G-quadruplex. The GQ-RCA assay enabled us to detect miRNA as low as 4.9 fM with a linear range from 25.6 fM to 80 pM within 0.5 h. In addition, our system was applied to the miRNA samples present in human plasma, showing its potential use in the clinical diagnosis of cancer.The presence of contaminants of emerging concern (CECs) in wastewater effluent and surface waters is an important field of research for analytical scientists. This study takes a suspect screening approach to wastewater and surface water analysis using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC × GC-TOFMS). Two extraction procedures, traditional liquid-liquid extraction (LLE) and stir bar sorptive extraction (SBSE), were utilized and evaluated for their application to wastewater and surface water samples. Both techniques were evaluated regarding their recovery rates, range of compound classes extracted, and on their application to discovery of CECs. For the 14 surrogate compounds analyzed, LLE was able to extract all of them in each matrix with a recovery range of 19% to 159% and a median value of 74%. For SBSE, the recovery rates ranged from 19% to 117% with the median value at 66%, but only 8 of the compounds were able to be extracted because of the polarity bias for this extraction method.
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