We here highlight the importance of stoichiometry for simultaneous cocrystal resolution. Focusing on combining the racemates of binol and proline, we show that a 1 : 2 ratio leads to formation of a ...full racemic compound, whereas a 2 : 1 ratio, leads to conglomerate formation, with simultaneous resolution of both binol and proline. Playing on stoichiometry, one achieves a reversible switch between the racemic compound and conglomerate. This is the first investigation of such behavior combining two racemates.
We here highlight the importance of stoichiometry for simultaneous cocrystal resolution.
Preferential crystallization induced by chiral surfaces is an interesting alternative to isolate enantiopure antipodes. Herein, we take advantage of the outstanding enantiorecognition capabilities of ...inherently chiral oligomers to induce an enantioselective crystallization process. We exemplify this strategy with two amino acid model molecules, asparagine and glutamic acid, having a completely uncorrelated structure with respect to the template. This illustrates the versatility of the approach with potential applications in the resolution of pharmaceutical compounds.
Chiral oligomers are proposed as templates for the chiral resolution of amino acids. High enantiomeric excess is achieved when they are employed as surfaces with electrochemically tunable hydrophilicity, despite their uncorrelated molecular structure.
Light spectra have been demonstrated to result in different levels of comfort or stress, which affect plant growth and the availability of health-promoting compounds in ways that sometimes contradict ...one another. To determine the optimal light conditions, it is necessary to weigh the vegetable's mass against the amount of nutrients it contains, as vegetables tend to grow poorly in environments where nutrient synthesis is optimal. This study investigates the effects of varying light conditions on the growth of red lettuce and its occurring nutrients in terms of productivities, which were determined by multiplying the total weight of the harvested vegetables by their nutrient content, particularly phenolics. Three different light-emitting diode (LED) spectral mixes, including blue, green, and red, which were all supplemented by white, denoted as BW, GW, and RW, respectively, as well as the standard white as the control, were equipped in grow tents with soilless cultivation systems for such purposes.
Results demonstrated that the biomass and fiber content did not differ substantially across treatments. This could be due to the use of a modest amount of broad-spectrum white LEDs, which could help retain the lettuce's core qualities. However, the concentrations of total phenolics and antioxidant capacity in lettuce grown with the BW treatment were the highest (1.3 and 1.4-fold higher than those obtained from the control, respectively), with chlorogenic acid accumulation (8.4 ± 1.5 mg g
DW) being particularly notable. Meanwhile, the study observed a high glutathione reductase (GR) activity in the plant achieved from the RW treatment, which in this study was deemed the poorest treatment in terms of phenolics accumulation.
In this study, the BW treatment provided the most efficient mixed light spectrum to stimulate phenolics productivity in red lettuce without a significant detrimental effect on other key properties.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
An improved process for the deracemization of a racemic conglomerate suspension of enantiomorphs has been created based on principles developed in an earlier method using temperature fluctuations. ...The method consists of circulating the suspension between two vessels, each controlled at a specific temperature in order to make the process more effective and faster to achieve a homochiral solid state. Crystals in the suspension were partially dissolved in the hot vessel, and the remaining crystals were regrown in the cold vessel. The crystals in the cold vessel have a longer residence time than those in the hot vessel to allow more time for the crystal growth process. The results show that complete deracemization can be achieved via this process far more rapidly than by using the previous temperature cycling (one-vessel) process. Moreover, the new process could easily be scaled up to an industrial scale. The current process can be an effective alternative to currently used enantiopurification methods, with simple processing implementation and low cost.
Higher education and student affairs graduate programs have attempted to prepare aspiring administrators to answer the call for increased multicultural competency through diversity courses, yet ...research suggests that new professionals feel ill-prepared to enact social justice work. Current instructional methods foster awareness but fail to cultivate reflective, culturally responsive practitioners. This qualitative case study explores how HESA graduate students' conceptions of critical consciousness evolve during a diversity course and the pedagogical practices that foster consciousness-raising.
Due to their lithotrophic metabolisms, morphological complexity and conspicuous appearance, members of the Beggiatoaceae have been extensively studied for more than 100 years. These bacteria are ...known to be primarily sulfur-oxidizing autotrophs that commonly occur in dense mats at redox interfaces. Their large size and the presence of a mucous sheath allows these cells to serve as sites of attachment for communities of other microorganisms. But little is known about their individual niche preferences and attached microbiomes, particularly in marine environments, due to a paucity of cultivars and their prevalence in habitats that are difficult to access and study. Therefore, in this study, we compare Beggiatoaceae strain composition, community composition, and geochemical profiles collected from sulfidic sediments at four marine stations off the coast of Namibia. To elucidate community members that were directly attached and enriched in both filamentous Beggiatoaceae, namely Ca. Marithioploca spp. and Ca. Maribeggiatoa spp., as well as non-filamentous Beggiatoaceae, Ca. Thiomargarita spp., the Beggiatoaceae were pooled by morphotype for community analysis. The Beggiatoaceae samples collected from a highly sulfidic site were enriched in strains of sulfur-oxidizing Campylobacterota, that may promote a more hospitable setting for the Beggiatoaceae, which are known to have a lower tolerance for high sulfide to oxygen ratios. We found just a few host-specific associations with the motile filamentous morphotypes. Conversely, we detected 123 host specific enrichments with non-motile chain forming Beggiatoaceae. Potential metabolisms of the enriched strains include fermentation of host sheath material, syntrophic exchange of H2 and acetate, inorganic sulfur metabolism, and nitrite oxidation. Surprisingly, we did not detect any enrichments of anaerobic ammonium oxidizing bacteria as previously suggested and postulate that less well-studied anaerobic ammonium oxidation pathways may be occurring instead.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A marine facultative anaerobe, strain SIP-G1T, was isolated from salt marsh sediments, Falmouth, MA, USA. Phylogenetic analysis of its 16S rRNA gene sequence indicated that it belongs to an ...unclassified clade of Gammaproteobacteria that includes numerous sulfur-oxidizing bacteria that are endosymbionts of marine invertebrates endemic to sulfidic habitats. Strain SIP-G1T is a member of the genus Sedimenticola, of which there is one previously described isolate, Sedimenticola selenatireducens AK4OH1T. S. selenatireducens AK4OH1T was obtained for further characterization and comparison with strain SIP-G1T. The two strains were capable of coupling the oxidation of thiosulfate, tetrathionate, elemental sulfur and sulfide to autotrophic growth and they produced sulfur inclusions as metabolic intermediates. They showed varying degrees of O2 sensitivity, but when provided amino acids or peptides as a source of energy, they appeared more tolerant of O2 and exhibited concomitant production of elemental sulfur inclusions. The organic substrate preferences and limitations of these two organisms suggest that they possess an oxygen-sensitive carbon fixation pathway(s). Organic acids may be used to produce NADPH through the TCA cycle and are used in the formation of polyhydroxyalkanoates. Cell-wall-deficient morphotypes appeared when organic compounds (especially acetate) were present in excess and reduced sulfur was absent. Levels of DNA-DNA hybridization (∼47%) and phenotypic characterization indicate that strain SIP-G1T represents a separate species within the genus Sedimenticola, for which the name Sedimenticola thiotaurini sp. nov. is proposed. The type strain is SIP-G1T ( = ATCC BAA-2640T = DSM 28581T). The results also justify emended descriptions of the genus Sedimenticola and of S. selenatireducens.
The use of optical micro-ring resonators as a platform for quantitative and qualitative biosensing applications was explored. Vertically coupled, high refractive index micro-ring resonators, used as ...sensing elements, were fabricated on silicon chips by photolithographic techniques. An optical reader system consisting of a near-infrared broad band light source and an optical spectrum analyzer were employed for data acquisition. Micro-ring resonator surfaces were modified with specific target receptors, including antibodies and single-stranded DNA oligonucleotides. The system was successfully used for label-free, specific, and rapid detection of whole bacterial cells, proteins and nucleic acids.
A racemic suspension of a conglomerate‐forming system can be converted to a homochiral suspension where the solute in the solution phase undergoes fast racemization through temperature fluctuations, ...i.e., temperature cycle‐induced deracemization. Previously, a mathematical model of chiral symmetry breaking due to differences in distributions of crystal growth rate activities between the two enantiomorphs was proposed. This model was a simplification since it used a very low number of crystals. Herein, the deracemization process was simulated using continuous distributions for the population of crystals and the growth rate of crystals which results in far more accurate simulations. The mechanism produces results similar to that achieved in experiments. The results from the gCrystal program demonstrated that complete chiral conversion to the enantiomorph with the wider dispersion in growth rate activity occurred in the solid phase.
A racemic suspension of conglomerate‐forming species can be converted to a homochiral suspension in a fast racemizing solution by temperature cycle‐induced deracemization. This process is modeled using the population balance model for the two enantiomorphs, applying the program gCrystal to obtain an accurate simulation of the evolution of the enantiomeric excess in the crystal phase.
Nutrient stewardship is emerging as an issue of global importance, which will drive the development of nutrient recovery in the near to medium future. This will impact wastewater treatment practices, ...environmental protection, sustainable agriculture and global food security. A modelling framework for precipitation-based nutrient recovery systems has been developed, incorporating non-ideal solution thermodynamics, a dynamic mass balance and a dynamic population balance to track the development of the precipitating particles. The mechanisms of crystal nucleation and growth and, importantly, aggregation are considered. A novel approach to the population balance embeds the nucleation rate into the model, enabling direct regression of its kinetic parameters. The case study chosen for the modelling framework is that of struvite precipitation, given its wide interest and commercial promise as one possible nutrient recovery pathway. Power law kinetic parameters for nucleation, crystal growth and particle aggregation rates were regressed from an ensemble data set generated from 14 laboratory seeded batch experiments using synthetic solutions. These experiments were highly repeatable, giving confidence to the regressed parameter values. The model successfully describes the dynamic responses of solution pH, the evolving particle size distribution subject to nucleation, growth and aggregation effects and the aqueous magnesium concentration in the liquid phase. The proposed modelling framework could well be extended to other, more complex systems, leading to an improved understanding and commensurately greater confidence in the design, operation and optimisation of large-scale nutrient recovery processes from complex effluents.
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•Process modelling framework for nutrient recovery through precipitation is presented.•Nucleation, crystal growth and aggregation processes drive a population balance.•Estimated parameters enable the model to describe experimental system.•Nucleation found to be the least significant mechanism.•The framework can be expanded to incorporate other solid phases and additional elements.
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