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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Environmental Sources of Bacteria Differentially Influence Host-Associated Microbial Dynamics

ABSTRACT Host-associated microbial dynamics are influenced by dietary and immune factors, but how exogenous microbial exposure shapes host-microbe dynamics remains poorly characterized. To investigate this phenomenon, we characterized the skin, rectum, and respiratory tract-associated microbiota in four aquarium-housed dolphins daily over a period of 6 weeks, including administration of a probiotic during weeks 4 to 6. The environmental bacterial sources were also characterized, including the animals’ human handlers, the aquarium air and water, and the dolphins’ food supply. Continuous microbial exposure occurred between all sites, yet each environment maintained a characteristic microbiota, suggesting that the majority of exposure events do not result in colonization. Small changes in water physicochemistry had a significant but weak correlation with change in dolphin-associated bacterial richness but had no influence on phylogenetic diversity. Food and air microbiota were the richest and had the largest conditional influence on other microbiota in the absence of probiotics, but during probiotic administration, food alone had the largest influence on the stability of the dolphin microbiota. Our results suggest that respiratory tract and gastrointestinal epithelium interactions with air- and food-associated microbes had the biggest influence on host-microbiota dynamics, while other interactions, such as skin transmission, played only a minor role. Finally, direct oral stimulation with a foreign exogenous microbial source can have a profound effect on microbial stability. IMPORTANCE Furthermore, these results provide valuable insights into the ecological influence of exogenous microbial exposure, as well as laying the foundation for improving aquarium management practices. By comparing data for dolphins from aquaria that use natural versus artificial seawater, we demonstrate the potential influence of aquarium water disinfection procedures on dolphin microbial dynamics.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Peroxisomes: versatile organelles with diverse roles in plants

Peroxisomes are small, ubiquitous organelles that are delimited by a single membrane and lack genetic material. However, these simple-structured organelles are highly versatile in morphology, abundance and protein content in response to various developmental and environmental cues. In plants, peroxisomes are essential for growth and development and perform diverse metabolic functions, many of which are carried out coordinately by peroxisomes and other organelles physically interacting with peroxisomes. Recent studies have added greatly to our knowledge of peroxisomes, addressing areas such as the diverse proteome, regulation of division and protein import, pexophagy, matrix protein degradation, solute transport, signaling, redox homeostasis and various metabolic and physiological functions. This review summarizes our current understanding of plant peroxisomes, focusing on recent discoveries. Current problems and future efforts required to better understand these organelles are also discussed. Here, an improved understanding of peroxisomes will be important not only to the understanding of eukaryotic cell biology and metabolism, but also to agricultural efforts aimed at improving crop performance and defense.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

ADP enhances the allosteric activation of eukaryotic elongation factor 2 kinase by calmodulin

Protein translation, one of the most energy-consumptive processes in a eukaryotic cell, requires robust regulation, especially under energy-deprived conditions. A critical component of this regulation is the suppression of translational elongation through reduced ribosome association of the GTPase eukaryotic elongation factor 2 (eEF-2) resulting from its specific phosphorylation by the calmodulin (CaM)-activated α–kinase eEF-2 kinase (eEF-2K). It has been suggested that the eEF-2K response to reduced cellular energy levels is indirect and mediated by the universal energy sensor AMP-activated protein kinase (AMPK) through direct stimulatory phosphorylation and/or downregulation of the eEF-2K-inhibitory nutrient-sensing mTOR pathway. Here, we provide structural, biochemical, and cell-biological evidence of a direct energy-sensing role of eEF-2K through its stimulation by ADP. A crystal structure of the nucleotide-bound complex between CaM and the functional core of eEF-2K phosphorylated at its primary stimulatory site (T348) reveals ADP bound at a unique pocket located on the face opposite that housing the kinase active site. Within this basic pocket (BP), created at the CaM/eEF-2K interface upon complex formation, ADP is stabilized through numerous interactions with both interacting partners. Biochemical analyses using wild-type eEF-2K and specific BP mutants indicate that ADP stabilizes CaM within the active complex, increasing the sensitivity of the kinase to CaM. Induction of energy stress through glycolysis inhibition results in significantly reduced enhancement of phosphorylated eEF-2 levels in cells expressing ADP-binding compromised BP mutants compared to cells expressing wild-type eEF-2K. These results suggest a direct energy-sensing role for eEF-2K through its cooperative interaction with CaM and ADP.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Precision Description of Processes at Colliders in the SANC System

A review of the SANC computer system intended for theoretical support of experiments at colliders is presented. The system allows the precision predictions to be obtained semiautomatically for a wide class of particle interaction processes within the Standard Model. In this case, one considers total contributions of one-loop radiative corrections. Basic elements of the computer system are described, and examples of using the system for the high-precision description of certain processes of the Standard Model particle interactions are given. The MCSANC code developed using the Monte Carlo simulation is presented, which is used to calculate cross sections of a number of processes, investigated at the Large Hadron Collider. The prospects of research development in this field for theoretical support at future hadron and lepton colliders are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Emulating a System Dynamics Model with Agent-Based Models: A Methodological Case Study in Simulation of Diabetes Progression

An agent-based simulation model hierarchy emulating disease states and behaviors critical to progression of diabetes type 2 was designed and implemented in the DEVS framework. The models are translations of basic elements of an established system dynamics model of diabetes. In this model hierarchy, which mimics diabetes progression over an aggregated U.S. population, was dis-aggregated and reconstructed bottom-up at the individual (agent) level. Four levels of model complexity were defined in order to systematically evaluate which parameters are needed to mimic outputs of the system dynamics model. Moreover, the four estimated models attempted to replicate stock counts representing disease states in the system dynamics model, while estimating impacts of an elderliness factor, obesity factor and health-related behavioral parameters. Health-related behavior was modeled as a simple realization of the Theory of Planned Behavior, a joint function of individual attitude and diffusion of social norms that spread over each agent s social network. Although the most complex agent-based simulation model contained 31 adjustable parameters, all models were considerably less complex than the system dynamics model which required numerous time series inputs to make its predictions. In all three elaborations of the baseline model provided significantly improved fits to the output of the system dynamics model. The performances of the baseline agent-based model and its extensions illustrate a promising approach to translate complex system dynamics models into agent-based model alternatives that are both conceptually simpler and capable of capturing main effects of complex local agent-agent interactions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Allostery revealed within lipid binding events to membrane proteins

Membrane proteins interact with a myriad of lipid species in the biological membrane, leading to a bewildering number of possible protein–lipid assemblies. Despite this inherent complexity, the identification of specific protein–lipid interactions and the crucial role of lipids in the folding, structure, and function of membrane proteins is emerging from an increasing number of reports. Fundamental questions remain, however, regarding the ability of specific lipid binding events to membrane proteins to alter remote binding sites for lipids of a different type, a property referred to as allostery. Here, we use native mass spectrometry to determine the allosteric nature of heterogeneous lipid binding events to membrane proteins. We monitored individual lipid binding events to the ammonia channel (AmtB) from Escherichia coli , enabling determination of their equilibrium binding constants. We found that different lipid pairs display a range of allosteric modulation. In particular, the binding of phosphatidylethanolamine and cardiolipin-like molecules to AmtB exhibited the largest degree of allosteric modulation, inspiring us to determine the cocrystal structure of AmtB in this lipid environment. The 2.45-Å resolution structure reveals a cardiolipin-like molecule bound to each subunit of the trimeric complex. Furthermore, mutation of a single residue in AmtB abolishes the positive allosteric modulation observed for binding phosphatidylethanolamine and cardiolipin-like molecules. Our results demonstrate that specific lipid–protein interactions can act as allosteric modulators for the binding of different lipid types to integral membrane proteins.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

A Global Survey of Deep Underground Facilities; Examples of Geotechnical and Engineering Capabilities, Achievements, Challenges (Mines, Shafts, Tunnels, Boreholes, Sites and Underground Facilities for Nuclear Waste and Physics R&D): A Guide to Interactive Global Map Layers, Table Database, References and Notes

These associated tables, references, notes, and report present a synthesis of some notable geotechnical and engineering information used to create four interactive layer maps for selected: 1) deep mines and shafts; 2) existing, considered or planned radioactive waste management deep underground studies or disposal facilities 3) deep large diameter boreholes, and 4) physics underground laboratories and facilities from around the world. These data are intended to facilitate user access to basic information and references regarding “deep underground” facilities, history, activities, and plans. In general, the interactive maps and database provide each facility’s approximate site location, geology, and engineered features (e.g.: access, geometry, depth, diameter, year of operations, groundwater, lithology, host unit name and age, basin; operator, management organization, geographic data, nearby cultural features, other). Although the survey is not comprehensive, it is representative of many of the significant existing and historical underground facilities discussed in the literature addressing radioactive waste management and deep mined geologic disposal safety systems. The global survey is intended to support and to inform: 1) interested parties and decision makers; 2) radioactive waste disposal and siting option evaluations, and 3) safety case development applicable to any mined geologic disposal facility as a demonstration of historical and current engineering and geotechnical capabilities available for use in deep underground facility siting, planning, construction, operations and monitoring.

58 GEOSCIENCES↗
DOE OSTI2019

Enhanced 1 H-X D-HMQC performance through improved 1 H homonuclear decoupling

The sensitivity of solid-state NMR experiments that utilize 1 H zero-quantum heteronuclear dipolar recoupling, such as D-HMQC, is compromised by poor homonuclear decoupling. This leads to a rapid decay of recoupled magnetization and an inefficient recoupling of long-range dipolar interactions, especially for nuclides with low gyromagnetic ratios. We investigated the use, in symmetry-based 1 H heteronuclear recoupling sequences, of a basic R element that was principally designed for efficient homonuclear decoupling. By shortening the time required to suppress the effects of homonuclear dipolar interactions to the duration of a single inversion pulse, spin diffusion was effectively quenched and long-lived recoupled coherence lifetimes could be obtained. Furthermore we show, both theoretically and experimentally, that these modified sequences can yield considerable sensitivity improvements over the current state-of-the-art methods and applied them to the indirect detection of 89Y in a metal-organic framework.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2019

Highly Drug-Resistant HIV-1 Protease Mutant PRS17 Shows Enhanced Binding to Substrate Analogues

We report the structural analysis of highly drug-resistant human immunodeficiency virus protease (PR) variant PR S17 , rationally selected by machine learning, in complex with substrate analogues. Crystal structures were solved of inhibitor-free inactive PR S17 -D25N, wild-type PR/CA-p2 complex, and PR S17 in complex with substrate analogues, CA-p2 and p2-NC. Peptide analogues p2-NC and CA-p2 exhibit inhibition constants of 514 and 22 nM, respectively, for PR S17 or approximately 3-fold better than for PR. CA-p2 is a better inhibitor of PR S17 than are clinical inhibitors ( K i = 50–8390 nM) except for amprenavir ( K i = 11 nM). G48V resistance mutation induces curled flap tips in PR S17 -D25N structure. The inner P2–P2' residues of substrate analogues in PR S17 complexes maintain similar conformations to those of wild-type complex, while significant conformational changes are observed in the peripheral residues P3, P4' of CA-p2 and P3, P4, and P3' of p2-NC. The loss of β-branched side chain by V82S mutation initiates a shift in 80’s loop and reshapes the S3/S3' subsite, which enhances substrate binding with new hydrogen bonds and van der Waals interactions that are absent in the wild-type structures. The steric hindrance caused by G48V mutation in the flap of PR S17 contributes to altered binding interactions of P3 Arg, P4' norleucine of CA-p2, and P4 and P3' of p2-NC with the addition of new hydrogen bonds and van der Waals contacts. The enhanced interaction of PR S17 with substrate analogues agrees with their relative inhibition, suggesting that this mutant improves substrate binding while decreasing affinity for clinical inhibitors.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Molecular mechanism of the dual activity of 4EGI-1: Dissociating eIF4G from eIF4E but stabilizing the binding of unphosphorylated 4E-BP1

The eIF4E-binding protein (4E-BP) is a phosphorylation-dependent regulator of protein synthesis. The nonphosphorylated or minimally phosphorylated form binds translation initiation factor 4E (eIF4E), preventing binding of eIF4G and the recruitment of the small ribosomal subunit. Signaling events stimulate serial phosphorylation of 4E-BP, primarily by mammalian target of rapamycin complex 1 (mTORC1) at residues T 37 /T 46 , followed by T 70 and S 65 . Hyperphosphorylated 4E-BP dissociates from eIF4E, allowing eIF4E to interact with eIF4G and translation initiation to resume. Because overexpression of eIF4E is linked to cellular transformation, 4E-BP is a tumor suppressor, and up-regulation of its activity is a goal of interest for cancer therapy. A recently discovered small molecule, eIF4E/eIF4G interaction inhibitor 1 (4EGI-1), disrupts the eIF4E/eIF4G interaction and promotes binding of 4E-BP1 to eIF4E. Structures of 14- to 16-residue 4E-BP fragments bound to eIF4E contain the eIF4E consensus binding motif, 54 YXXXXLΦ 60 (motif 1) but lack known phosphorylation sites. We report in this paper a 2.1-Å crystal structure of mouse eIF4E in complex with m 7 GTP and with a fragment of human 4E-BP1, extended C-terminally from the consensus-binding motif (4E-BP1 50–84 ). The extension, which includes a proline-turn-helix segment (motif 2) followed by a loop of irregular structure, reveals the location of two phosphorylation sites (S 65 and T 70 ). Our major finding is that the C-terminal extension (motif 3) is critical to 4E-BP1–mediated cell cycle arrest and that it partially overlaps with the binding site of 4EGI-1. Finally, the binding of 4E-BP1 and 4EGI-1 to eIF4E is therefore not mutually exclusive, and both ligands contribute to shift the equilibrium toward the inhibition of translation initiation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Catabolism and interactions of uncultured organisms shaped by eco-thermodynamics in methanogenic bioprocesses

We currently understand the carbon cycle in methanogenic environments as trophic interactions revolving around interspecies H 2 transfer between organotrophs and methanogens. However, many H 2 -generating processes are thermodynamically sensitive to H 2 accumulation and can be inhibited by high H 2 concentrations produced by other metabolisms. To uncover how anaerobes combat this H 2 conflict in situ, we employ metagenomics and metatranscriptomics to revisit a model ecosystem that has inspired many foundational discoveries in anaerobic ecology – methanogenic bioreactors. Through analysis of 15 anaerobic digesters, we recover 1343 high-quality metagenome-assembled genomes (MAGs) and corresponding gene expression profiles for diverse uncultured lineages spanning 66 phyla and reconstruct their individual metabolic capacities. We discover that diverse uncultured organotrophic populations can drive H 2 -sensitive degradation through (i) metabolic coupling with concurrent H 2 -tolerant catabolism, (ii) unprecedented shifts from H 2 generation to CO 2 -reducing formate transfer and cytochrome/pili-mediated direct interspecies electron transfer for avoiding thermodynamic conflict, and (iii) integration of low-concentration O 2 as an ancillary thermodynamics-enhancing electron sink. Archaeal populations in situ support the above processes through novel metabolisms distinct from conventional methanogenesis – high-affinity H 2 oxidation driven by methyl-reducing methanogenesis and concomitant uptake of formate, electrons, and acetate from HS metabolism by Methanothrix. In total, synthesis of omics analyses and eco-thermodynamics reveals overlooked metabolic behavior and interactions of uncultured organisms that address a central issue in methanogenic carbon cycling, thermodynamic conflict among diverse concurrent metabolic processes.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

A Cobalamin Activity-Based Probe Enables Microbial Cell Growth and Finds New Cobalamin-Protein Interactions across Domains

Understanding the factors that regulate microbe function and microbial community assembly, function, and fitness is a grand challenge. A critical factor and an important enzyme cofactor and regulator of gene expression is cobalamin (vitamin B 12 ). Our knowledge of the roles of vitamin B 12 is limited, because technologies that enable in situ characterization of microbial metabolism and gene regulation with minimal impact on cell physiology are needed. To meet this need, here we show that a synthetic probe mimic of B 12 supports the growth of B 12 -auxotrophic bacteria and archaea. We demonstrate that a B 12 activity-based probe (B 12 -ABP) is actively transported into Escherichia coli cells and converted to adenosyl-B 12 -ABP akin to native B 12 . Identification of the proteins that bind the B 12 -ABP in vivo in E. coli, a Rhodobacteraceae sp. and Haloferax volcanii, demonstrate the specificity for known and novel B 12 protein targets. The B 12 -ABP also regulates the B 12 dependent RNA riboswitch btuB and the transcription factor EutR. Our results demonstrate a new approach to gain knowledge about the role of B 12 in microbe functions. Our approach provides a powerful nondisruptive tool to analyze B 12 interactions in living cells and can be used to discover the role of B 12 in diverse microbial systems.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Poxvirus infection triggers remodeling of host m⁶A epitranscriptome and benefits from the m⁶A regulatory responses

Understanding how host gene regulation responds to viral infection is essential for developing effective antiviral strategies. Emerging evidence suggests that host transcripts undergo dynamic chemical modifications to counteract viral invasion. Conversely, viruses that rely on nuclear transcription exploit host RNA methyltransferases to enhance mRNA export and translation. Orthopoxviruses, however, complete their entire replication cycle within compartmentalized cytoplasmic “factories” utilizing enzymes encoded by their large double-stranded viral DNA genomes. The dynamic interplay between host and poxviral epitranscriptome remains poorly characterized. Using a temporally resolved model of Vaccinia virus (VV) infection, we investigated host-virus interactions through transcriptome and N6-methyladenosine (m⁶A) epitranscriptome whole genome sequencing. We found that host m⁶A modifications respond rapidly to VV infection, preceding the delayed transcriptional changes that emerge at later stages. Early m⁶A signatures included key innate immunity factors as well as host genes involved in transcriptional regulation, post-transcriptional modification, and protein ubiquitination. Functional assays validated two host factors with early m⁶A modification changes that are essential for VV infection: a m⁶A reader, YTHDF1, and a component of the SCF E3 ubiquitin ligase complex, FBXO31. The m⁶A gain on YTHDF1 enhanced its protein expression and promoted efficient VV replication. In addition, we identified previously unrecognized roles of FBXO31 and the SCF E3 ligase complex in supporting VV infection. Temporal profiling of the m⁶A epitranscriptome reveals how VV exploits host post-transcriptional regulatory pathways, specifically m⁶A RNA modification and protein ubiquitination. These findings highlight critical host factors co-opted during poxvirus infection and identify potential targets for therapeutic intervention.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Phoresy in animals: review and synthesis of a common but understudied mode of dispersal

Phoresy is a type of interaction in which one species, the phoront, uses another species, the dispersal host, for transportation to new habitats or resources. Despite being a widespread behaviour, little is known about the ecology and evolution of phoresy. Our goal is to provide a comprehensive review of phoretic dispersal in animals and to bring renewed attention to this subject. We surveyed literature published between 1900 and 2020 to understand the extent of known higher-level taxonomic diversity (phyla, classes, and orders) and functional aspects of animals that use phoretic dispersal. Species dispersing phoretically have been observed in at least 13 animal phyla, 25 classes, and 60 orders. The majority of known phoronts are arthropods (Phylum Euarthropoda) in terrestrial habitats, but phoronts also occur in freshwater and marine environments. Marine phoronts may be severely under-represented in the literature due to the relative difficulty of studying these systems. Phoronts are generally small with low mobility and use habitats or resources that are ephemeral and/or widely dispersed. Many phoronts are also parasites. In general, animals that engage in phoresy use a wide variety of morphological and behavioural traits for locating, attaching to, and detaching from dispersal hosts, but the exact mechanisms behind these activities are largely unknown. In addition to diversity, we discuss the evolution of phoresy including the long-standing idea that it can be a precursor to parasitism and other forms of symbioses. To conclude, we suggest several areas of future research to improve our understanding of phoresy and its ecological and evolutionary significance.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Dehydration of UO 2 Cl 2 ·3H 2 O and Nd(NO 3 ) 3 ·6H 2 O with a Soft Donor Ligand and Comparison of Their Interactions through X-ray Diffraction and Theoretical Investigation [plus Supplemental Information]

Herein we investigated whether the relatively Lewis basic imidazole-2-thiones could be used to substitute water ligands bound to f-element cations and generate f-element soft donor complexes. Reactions of 1,3-diethylimidazole-2-thione (C 2 C 2 ImT) with Nd(NO 3 ) 3 ·6H 2 O and UO 2 Cl 2 ·3H 2 O led to the isolation of the anhydrous thione complexes Nd(NO 3 ) 3 (C 2 C 2 ImT) 3 and UO 2 Cl 2 (C 2 C 2 ImT) 2 , characterized by single crystal X-ray diffraction. Differences in the strength of metal–thione interactions have been examined by means of the crystal structure analysis and density functional theory (DFT) calculations. The C 2 C 2 ImT ligands were found to be affected by both coordination and noncovalent interactions, making it impossible to deconvolute the effects of one from the other. Calculated partial atomic charges indicated greater ligand-to-metal charge transfer in the [UO 2 ] 2+ complex, indicative of a stronger interaction. The reactivity of C 2 C 2 ImT demonstrates its usefulness in the preparation of f-element soft donor complexes from readily available hydrates that could be useful intermediates for promoting the coordination and studying the effects of soft donor anions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Vorticity dynamics after the shock–turbulence interaction

In this article, the interaction of a shock wave with quasi-vortical isotropic turbulence (IT) represents a basic problem for studying some of the phenomena associated with high speed flows, such as hypersonic flight, supersonic combustion and Inertial Confinement Fusion (ICF). In general, in practical applications, the shock width is much smaller than the turbulence scales and the upstream turbulent Mach number is modest. In this case, recent high resolution shock-resolved Direct Numerical Simulations (DNS) (Ryu and Livescu, J Fluid Mech 756, R1, 2014) show that the interaction can be described by the Linear Interaction Approximation (LIA). Using LIA to alleviate the need to resolve the shock, DNS post-shock data can be generated at much higher Reynolds numbers than previously possible. Here, such results with Taylor Reynolds number approximately 180 are used to investigate the changes in the vortical structure as a function of the shock Mach number, M s , up to M s = 10. It is shown that, as M s increases, the shock interaction induces a tendency towards a local axisymmetric state perpendicular to the shock front, which has a profound influence on the vortex-stretching mechanism and divergence of the Lamb vector and, ultimately, on the flow evolution away from the shock.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2017

Iridium Complexes with Proton-Responsive Azole-Type Ligands as Effective Catalysts for CO 2 Hydrogenation

Pentamethylcyclopentadienyl iridium (Cp*Ir) complexes with bidentate ligands consisting of a pyridine ring and an electron-rich diazole ring were prepared. Their catalytic activity towards CO 2 hydrogenation in 2.0 M KHCO 3 aqueous solutions (pH 8.5) at 50 °C, under 1.0 MPa CO 2 /H 2 (1:1) have been reported as an alternative to photo- and electrochemical CO 2 reduction. Bidentate ligands incorporating an electron-rich diazole ring improved the catalytic performance of the Ir complexes compared to the bipyridine ligand. Complexes 2, 4 and 6, possessing both a hydroxy group and an uncoordinated NH group, which are proton-responsive and capable of generating pendent-bases in basic media, recorded high initial TOF values of 1300 h -1 , 1550 h -1 and 2000 h -1 , respectively. Here, spectroscopic and computational investigations revealed that the reversible deprotonation changes the electronic properties of the complexes and causes interactions between pendent base and substrate and/or solvent water molecules, resulting in the high catalytic performance in basic media.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗