Publications by authors named "Eberhart M"

A novel solid electrolyte sensor with considerably improved response times is presented. The new so-called eFIPEX [etched flux (Φ) probe experiment] is based on the FIPEX [flux (Φ) probe experiment] sensor applied for the measurement of molecular and atomic oxygen concentrations. A main application is the measurement of atmospheric atomic oxygen aboard sounding rockets up to altitudes of 250 km.

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It is broadly recognized that intramolecular electric fields, produced by the protein scaffold and acting on the active site, facilitate enzymatic catalysis. This field effect can be described by several theoretical models, each of which is intuitive to varying degrees. In this contribution, we show that a fundamental effect of electric fields is to generate electrostatic potentials that facilitate the energetic alignment of reactant frontier orbitals.

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Space exploration missions rely on ablative heat shields for the thermal protection of spacecraft during atmospheric entry flights. While dedicated research is needed for future missions, the scientific community has limited access to ablative materials typically used in aerospace. In this paper, we report the development of the HEFDiG Ablation-Research Laboratory Experiment Material (HARLEM), a carbon-phenolic ablator designed to supply the need for ablative materials in laboratory experiments.

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Observational studies demonstrated 30% to 40% effectiveness of outer-membrane vesicle (OMV) meningococcal serogroup B vaccines against gonorrhea. To explore whether healthy vaccinee bias influenced such findings, we examined the effectiveness of MenB-FHbp, a non-OMV vaccine that is not protective against gonorrhea. MenB-FHbp was ineffective against gonorrhea.

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The nascent field of computationally aided molecular design will be built around the ability to make computation useful to synthetic chemists who draw on their empirically based chemical intuition to synthesize new and useful molecules. This fact poses a dilemma, as much of existing chemical intuition is framed in the language of chemical bonds, which are pictured as possessing physical properties. Unfortunately, it has been posited that calculating these bond properties is impossible because chemical bonds do not exist.

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Enzymes host active sites inside protein macromolecules, which have diverse, often incredibly complex, and atom-expensive structures. It is an outstanding question what the role of these expensive scaffolds might be in enzymatic catalysis. Answering this question is essential to both enzymology and the design of artificial enzymes with proficiencies that will match those of the best natural enzymes.

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Bond bundle analysis is used to investigate enzymatic catalysis in the ketosteroid isomerase (KSI) active site. We identify the unique bonding regions in five KSI systems, including those exposed to applied oriented electric fields and those with amino acid mutations, and calculate the precise redistribution of electron density and other regional properties that accompanies either enhancement or inhibition of KSI catalytic activity. We find that catalytic enhancement results from promoting both inter- and intra-molecular electron density redistribution, between bond bundles and bond wedges within the KSI-docked substrate molecule, in the forward direction of the catalyzed reaction.

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The fundamental construct of organic chemistry involves understanding molecular behavior through functional groups. Much of computational chemistry focuses on this very principle, but metallic materials are rarely analyzed using these techniques owing to the assumption that they are delocalized and do not possess inherent functionality. In this paper, we propose a methodology that recovers functional groups in metallic materials from an energy perspective.

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Article Synopsis
  • There is a growing concern about the rise in antibiotic-resistant gonorrhoea and limited treatment options, highlighting the need for new preventive measures such as vaccination.* -
  • The study evaluated the effectiveness of the MenB-4C vaccine against gonorrhoea in young individuals (ages 16-23) in New York City and Philadelphia by linking infection records with vaccination status.* -
  • Findings showed that individuals who completed the MenB-4C vaccination series had lower rates of gonorrhoea infection compared to those who were unvaccinated, suggesting that the vaccine may offer some level of protection.*
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A novel form of charge density analysis, that of isosurface curvature redistribution, is formulated and applied to the toy problem of carbonyl oxygen activation in formaldehyde. The isosurface representation of the electron charge density allows us to incorporate the rigorous geometric constraints of closed surfaces toward the analysis and chemical interpretation of the charge density response to perturbations. Visual inspection of 2D isosurface motion resulting from applied external electric fields reveals how the isosurface curvature flows within and between atoms and that a molecule can be uniquely and completely partitioned into chemically significant regions of positive and negative curvatures.

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Light field deconvolution allows three-dimensional investigations from a single snapshot recording of a plenoptic camera. It is based on a linear image formation model, and iterative volume reconstruction requires to define the backprojection of individual image pixels into object space. This is effectively a reversal of the point spread function (PSF), and backprojection arrays H' can be derived from the shift-variant PSFs H of the optical system, which is a very time consuming step for high resolution cameras.

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For the better part of a century researchers across disciplines have sought to explain the crystallography of the elemental transition metals: hexagonal close packed, body centered cubic, and face centered cubic in a form similar to that used to rationalize the structure of organic molecules and inorganic complexes. Pauling himself tried with limited success to address the origins of transition metal stability. These early investigators were handicapped, however, by incomplete knowledge regarding the structure of metallic electron density.

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We performed a retrospective case-control cohort study following 146 preterm infants (≤32 weeks of gestation) who had been colonized with extended spectrum beta-lactamase producing Enterobacterales and compared them with 1:1 matched controls regarding rates of hospitalizations and outpatient visits because of infectious and gastrointestinal diseases and developmental impairment up to school age. Preterm infants with extended spectrum beta-lactamase producing Enterobacterales colonization did have neither higher rates of gastrointestinal or infectious diseases nor higher rates of developmental impairments up to the age of 6 years.

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The development and investigation of materials that leverage unique interfacial effects on electronic structure and redox chemistry are likely to play an outstanding role in advanced technologies for wastewater treatment. Here, the use of surface functionalization of metal oxides with a Ru poly(pyridyl) complex was reported as a way to create hybrid assemblies with optimized electrochemical performance for water remediation, superior to those that could be achieved with the molecular catalyst or metal-oxide electrodes used individually. Mechanistic analysis demonstrated that the molecularly functionalized electrodes could suppress the formation of hydroxyl radicals (i.

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Aim: Face masks are essential during the COVID-19 pandemic, and the United Nations Children's Fund and the World Health Organization, recommend that they are used for children aged six years and older. However, parents are increasingly expressing concerns about whether these might be physically harmful. This mini review assessed the evidence.

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Heteroleptic copper(i) bis(phenanthroline) complexes with surface anchoring carboxylate groups have been synthesized and immobilized on nanoporous metal oxide substrates. The species investigated are responsive to the external environment and this work provides a new strategy to control charge transfer processes for efficient solar energy conversion.

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Purpose: Microbial dysbiosis has been found preceding necrotizing enterocolitis (NEC) in preterm infants; thus, we aimed to investigate whether there is evidence that neonates with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) positive stool cultures are at higher risk for NEC at the NICU.

Methods: We included very preterm inborn infants of ≤ 32 weeks of gestational age being fecal carriers of ESBL-E and compared them with 1:1 matched (gestational age, birth weight, gender and year) controls tested negative for ESBL-E in the stool between 2005 and 2016. An association with NEC was defined as the first detection of ESBL-E before or at the time of definite diagnosis of NEC.

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Our curiosity-driven desire to "see" chemical bonds dates back at least one-hundred years, perhaps to antiquity. Sweeping improvements in the accuracy of measured and predicted electron charge densities, alongside our largely bondcentric understanding of molecules and materials, heighten this desire with means and significance. Here we present a method for analyzing chemical bonds and their energy distributions in a two-dimensional projected space called the condensed charge density.

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Stabilization is a critical issue in the long term operation of dye-sensitized photoelectrosynthesis cells (DSPECs) for water splitting or CO reduction. The cells require a stable binding of the robust molecular chromophores, catalysts, and chromophore/catalyst assemblies on metal oxide semiconductor electrodes under the corresponding (photoelectro)chemical conditions. Here, an efficient stabilization strategy is presented based on functionalization of FTOTiO (mesoporous, nanostructured TiO deposited on fluorine-doped tin oxide (FTO) glass) electrodes with a vinylsilane followed by surface reductive electropolymerization of a vinyl-derivatized Ru(II) polypyridyl chromophore.

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Large protein macromolecules in enzymatic catalysis have been shown to exert a specific electric field that reduces the reorganization energy upon barrier crossing and thus reduces the reaction free energy barrier. In this work we suggest that the charge density in the active site of an enzyme investigated using formalisms embodied by the quantum theory of atoms in molecules (QTAIM) provides a sensitive and quantum mechanically rigorous probe of electrostatic preorganization. We focus on the active site of ketosteroid isomerase, a well-studied enzyme for which electrostatic preorganization has been modeled theoretically and studied experimentally.

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Article Synopsis
  • A mesoporous atomic layer deposition (ALD) double-shell electrode was created for use in a photoanode, aimed at enhancing light-driven water oxidation.
  • High photocurrent densities were achieved due to an effective barrier to back electron transfer, which was optimized by the tunneling barrier and built-in electric field at the interface of the ALD layers.
  • Studies using kinetic nanosecond transient absorption spectra provided insights into the charge recombination processes and the internal electronic structure of the electrode films.
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Binding functional molecules to nanostructured mesoporous metal oxide surfaces provides a way to derivatize metal oxide semiconductors for applications in dye-sensitized photoelectrosynthesis cells (DSPECs). The commonly used anchoring groups, phosphonates and carboxylates, are unstable as surface links to oxide surfaces at neutral and high pH, leading to rapid desorption of appended molecules. A synthetically versatile molecular attachment strategy based on initial surface modification with a silyl azide followed by click chemistry is described here.

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