2,654 research outputs found
Certain minimal varieties are set-theoretic complete intersections
We present a class of homogeneous ideals which are generated by monomials and
binomials of degree two and are set-theoretic complete intersections. This
class includes certain reducible varieties of minimal degree and, in
particular, the presentation ideals of the fiber cone algebras of monomial
varieties of codimension two
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Studying Lactoferrin N-Glycosylation.
Lactoferrin is a multifunctional glycoprotein found in the milk of most mammals. In addition to its well-known role of binding iron, lactoferrin carries many important biological functions, including the promotion of cell proliferation and differentiation, and as an anti-bacterial, anti-viral, and anti-parasitic protein. These functions differ among lactoferrin homologs in mammals. Although considerable attention has been given to the many functions of lactoferrin, its primary nutritional contribution is presumed to be related to its iron-binding characteristics, whereas the role of glycosylation has been neglected. Given the critical role of glycan binding in many biological processes, the glycan moieties in lactoferrin are likely to contribute significantly to the biological roles of lactoferrin. Despite the high amino acid sequence homology in different lactoferrins (up to 99%), each exhibits a unique glycosylation pattern that may be responsible for heterogeneity of the biological properties of lactoferrins. An important task for the production of biotherapeutics and medical foods containing bioactive glycoproteins is the assessment of the contributions of individual glycans to the observed bioactivities. This review examines how the study of lactoferrin glycosylation patterns can increase our understanding of lactoferrin functionality
Alternative Liquid Fuels for Transportation
This paper reviews present studies at F.I.T. intended to identify, evaluate, and develop alternative liquid fuels for transportation which can be derived from biomass using noncapital intensive processes
An Introduction to the Viable Systems Approach and its Contribution to Marketing
Organizations are increasingly challenged by dynamism and turbulence that determine conditions of complexity in decision making. The aim of this paper is to highlight the need for a general frame of reference for management and marketing and to justify why adopting a systems approach is adequate at both theoretical and practical level. Specifically, the purpose of this paper is to explain why a systems approach is needed to understand business and market dynamics, and why the VSA
may represent a good integrator of management and marketing theories and practices. The paper begins with a brief review of systems theories that have been
proposed in the general context of management and marketing. It proceeds by illustrating the fundamental principles and concepts of the VSA and its contribution to
marketing. The paper closes by discussing future research avenues and suggesting implications for researchers and practitioners
On the distribution and characteristics of isozyme expression in Mycoplasma, Acholeplasma, and Ureaplasma species.
A summary of a survey of three genera of mycoplasmatales (Mycoplasma, Acholeplasma, and Ureaplasma) for isozyme expression is presented. Isozyme analysis of mycoplasmas has been employed in at least three distinct areas: (1) as genetic markers for identification, individualization, and taxonomic classification; (2) as markers for cell culture contamination; and (3) as a qualitative measure of the operative metabolic pathways in the diverse species. We have found five ubiquitous enzymes: purine nucleoside phosphorylase, adenylate kinase, inorganic pyrophosphatase, dipeptidase, and esterase. Three enzymes, glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, and superoxide dismutase, were restricted to Acholeplasma species and were not detected in Mycoplasma or Ureaplasma. Four glycolytic enzymes, glucose phosphate isomerase, triose phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, and lactate dehydrogenase, were restricted to those species of Mycoplasma and Acholeplasma capable of glucose fermentation. Two of these glycolytic enzymes, glucose phosphate isomerase and lactate dehydrogenase, were detected in serovars I and II of U. urealyticum, which is inconsistent with the non-glycolytic activity in this genus
Polarizations and differential calculus in affine spaces
Within the framework of mappings between affine spaces, the notion of -th
polarization of a function will lead to an intrinsic characterization of
polynomial functions. We prove that the characteristic features of derivations,
such as linearity, iterability, Leibniz and chain rules, are shared -- at the
finite level -- by the polarization operators. We give these results by means
of explicit general formulae, which are valid at any order , and are based
on combinatorial identities. The infinitesimal limits of the -th
polarizations of a function will yield its -th derivatives (without
resorting to the usual recursive definition), and the above mentioned
properties will be recovered directly in the limit. Polynomial functions will
allow us to produce a coordinate free version of Taylor's formula
Algorithm and Human Creativity: Threats or Opportunity? A Literature Review
We explore the move from a mechanical vision of Artificial Intelligence (AI) to a systemic
vision of Intelligence Augmentation (IA) (Barile et al., 2018, 2019, 2020, 2021;
Navarrini, 2020; Chiriatti, 2019). AI assumes the role of empowered intelligence (IA)
as it is capable of expressing a capacity for modeling integration of experiences, knowledge
and emotions in conditions of strong uncertainty (Barile et al., 2021; Hagel,
2021). But in a world where the nature of machine learning is changing so rapidly,
does technology empower or annihilate creativity? The aim of the paper is to draw
attention to the impact that disruptive technology has on human creative processes.
How might progress in AI affect Human Creativity (HC)?We propose a literature review
to better understand both trends and gaps
Tolerability and safety of the intake of bovine milk oligosaccharides extracted from cheese whey in healthy human adults.
Mechanistic research suggests a unique evolutionary relationship between complex milk oligosaccharides and cognate bifidobacteria enriched in breast-fed infants. Bovine milk oligosaccharides (BMO) were recently identified as structurally and functionally similar to human milk oligosaccharides. The present single-blind three-way crossover study is the first to determine the safety and tolerability of BMO consumption by healthy human participants (n 12) and its effects on faecal microbiota and microbial metabolism. Participants consumed each supplement (placebo-control; low- and high-BMO doses) for eleven consecutive days, followed by a 2-week washout period prior to initiating the next supplement arm. Low and high BMO doses were consumed as 25 and 35 % of each individual's daily fibre intake, respectively. Safety and tolerability were measured using standardised questionnaires on gut and stomach discomfort and stool consistency. Faecal extracts were profiled for bacterial populations by next-generation sequencing (NGS) and bifidobacteria presence was confirmed using quantitative PCR. Urine was analysed for changes in microbial metabolism using nuclear magnetic resonance spectroscopy (1H-NMR). Consumption of both the low and high BMO doses was well tolerated and did not change stool consistency from baseline. Multivariate analysis of the NGS results demonstrated no change in faecal microbiota phyla among the placebo-control and BMO supplement groups. In conclusion, BMO supplementation was well tolerated in healthy adults and has the potential to shift faecal microbiota toward beneficial strains as part of a synbiotic treatment with probiotic cultures that selectively metabolise oligosaccharides
Analysis of Multiple Isoenzyme Expression Among Twenty-Two Species of Mycoplasma and Acholeplasma
Crude extracts of triple-cloned, purified cultures of 22 species of Mycoplasma and Acholeplasma were examined for expression of 21 isozyme systems routinely used to type mammalian cells. Nine previously described enzymes (purine nucleoside phosphorylase, adenylate kinase, dipeptidase, esterase, glyceraldehyde-3-phosphate dehydrogenase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and superoxide dismutase) and three enzymes not previously reported in mycoplasma (triose phosphate isomerase, inorganic pyrophosphatase, and acid phosphatase) were detected in some or all of the species examined. These findings provide new information on the enzymatic expressions of these organisms. Three of the isozyme systems (superoxide dismutase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) were present in Acholeplasma species but not in any Mycoplasma species. The characteristic pattern of electrophoretic mobility of the 12 isozyme systems also provides a useful biochemical property for identification, characterization, and classification of these mycoplasmas. Mycoplasma isozyme expression for seven of the enzymes were readily detected in various infected-cell culture lines by using either cell extracts or concentrated cell culture fluids. Mycoplasma-specific enzymes found in infected-cell extracts had the same electrophoretic mobility patterns as enzymes obtained from broth-grown mycoplasmas of the same species. Expression of homologous mammalian enzymes was not detectably altered by infection with mycoplasmas
Design and characterization of advanced battery technologies and mechanistic studies of the oxygen reduction reaction for fuel cells
About one fifth of the world’s energy consumption comes from the transportation sector. To fully address the problems associated with climate change, pollution, and energy security, the transportation sector must transition away from fossil fuel-based energy sources. When coupled with clean and renewable energy production technologies such as solar and wind, vehicles powered by batteries or hydrogen fuel cells could enable this transition.
Automobiles powered by Li-ion batteries have already been commercialized on a modest scale, but these vehicles suffer from limited range, temperature intolerance, and high production costs. The performance of Li-ion batteries must substantially improve to facilitate the widespread implementation of electric vehicles. Alternatively, altogether new battery chemistries that promise higher energy densities can be employed.
Chapters 2-6 of this thesis investigate two battery chemistries, the Li-O2 and Mg-ion batteries, which have higher theoretical energy densities than current Li-ion batteries. Results from a wide variety of analytical techniques underscore some of the largest hurdles hindering the commercialization of these devices. Several examples of new materials and operating procedures suggest potential directions to pursue to overcome these problems in the future.
The last three chapters of this thesis investigate fundamental questions that relate to hydrogen fuel cells. The sluggish nature of the O2 reduction reaction to water, which occurs at fuel cell cathodes, is one of the main obstacles preventing the widespread commercialization of these devices. Despite many decades of research, precise mechanistic understanding of this important reaction remains elusive, thereby obfuscating rational catalyst design. This work describes the development of a unique electrochemical platform called a hybrid bilayer membrane that enables the kinetics of proton transfer to an O2 reduction catalyst to be controlled. The insight gained from this novel approach highlights the subtle interplay between proton transfer, electron transfer and bond-breaking events that occurs during O2 reduction, which should aid future catalyst development
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