Habits and Binds of Mathematics Education in the Anthropocen

<p>(a) A signaling network for cell death regulation [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0165049#pone.0165049.ref011" target="_blank">11</a>]. Cell death is enhanced due to DNA damage while inhibited by the signals transmitted from EGFR. The arrow shape represents activation while a flat-head edge means inhibition. Pink nodes denote the species that have experimental measurements. (b) The simulation results of DNA Damage and Cell Death.</p

Complete mitochondrial genome of <i>Laeocathaica amdoana</i> Möllendorff, 1899 and phylogenetic analysis of Camaenidae (Gastropoda: Stylommatophora: Helicoidea)

The first complete mitochondrial genome of the dart sac-bearing camaenid Laeocathaica Möllendorff, 1899 was sequenced and analyzed in this study. The whole mitogenome of Laeocathaica amdoana Möllendorff, 1899 was 14,660 bp in length and its nucleotide composition showed high AT-content of 67.45%. It had 37 genes, including 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. The phylogeny yielded by both Bayesian inference and maximum-likelihood method suggested that Laeocathaica was closely related to the other dart sac-bearing camaenids with known complete mitochondrial genome. These genetic data are expected to provide fundamental resources for further genetic studies on the camaenids.</p

Determination of the Emulsion Stabilization Mechanisms of Quaternized Glucan of Curdlan via Rheological and Interfacial Characterization

Interfacial-active quaternized glucan of curdlan (QCD) with different degrees of substitution (DS) was prepared and used as stabilizers of oil-in-water (O/W) emulsions at different concentrations. The adsorption behavior of QCDs, rheology of bulk emulsions and interfacial films, emulsion morphology, and stability were investigated. The emulsifying capacity of QCD was essentially related to the viscoelastic features of the interfacial film and the continuous phase and the electrostatic repulsion among oil droplets. QCD molecules with different DS form structurally different interfacial films. The high-DS QCD formed a viscously predominant interfacial film with certain hydrophobicity, whereas the low-DS QCD molecules formed an elastically predominant film characterized by hydrogen bonds among adsorbed chains. The structuralization of low-DS QCD molecules through physical cross-linking in bulk and interfacial films at high concentrations was conducive to emulsion stability. Excess QCD chains in the bulk formed a weak gel-like network, further hindering the movement of droplets in the emulsions. Relevant emulsification and stability mechanisms were proposed. Finally, the stability of curcumin encapsulated in O/W emulsions was evaluated

β-Scission of the N−O Bond in Alkyl Hydroxamate Radicals: A Fast Radical Trap

The rate of the β-scission of the N−O bond in the alkyl hydroxamate radical is faster than 2 × 108 s-1. This reaction may be useful as a radical trap

Absorption Spectra of RiboflavinA Difficult Case for Computational Chemistry

Computing accurate absorption spectra of riboflavin (RBF) has proven a difficult task for computational chemistry. Time-dependent density functional theory have herein been employed using a wide range of recent range-separated and hybrid meta functionals to investigate ultraviolet and visible spectra of RBF to determine if any progress has been made through recent developments. It is concluded that B3LYP and PBE0 perform the best throughout the entire test set. However, since all methods deviate from experimental results by at least 40 nm when computing the spectra in vacuum, two approaches to describe aqueous solution are implemented together with the MPWB1K, B3LYP, and PBE0 functionals: implicitly using integral equation formulation of the polarized continuum model (minor improvement) and explicitly through molecular dynamics (MD) simulations of the molecule embedded in a water cluster whereafter snapshots of RBF−water clusters are extracted and time-dependent density functional theory calculations performed. The resulting averaged spectra from the MD-simulated clusters show a constant blue-shift for all peaks by ∼20 nm compared to experimental data at the TD-B3LYP/6-31+G(d,p) level

Assaying glycolytic flux and glycolytic capacity.

<p>A. Kinetic ECAR response of HeLa cells to glucose (10 mM), oligomycin (2 µM), and 2-DG (100 mM). Insert shows OCR response in response to glucose and oligomycin. HeLa cells were plated at 30,000/well in XF24 V7 cell culture plates 24–28 hours prior to the assays. The assay medium was the substrate-free base medium supplemented with 2 mM glutamine. ECAR or OCR values were not normalized. A representative experiment out of at 5 is shown here. Each data point represents mean ± SD, n = 4. B. Calculated glycolytic flux, glycolytic capacity. Glycolytic flux is the difference between the ECARs of measurement 6 and measurement 3. Likewise, glycolytic capacity describes the difference between the ECAR of measurement 9 and that of measurement 3. * p<0.05.</p

Rapid Analysis of Glycolytic and Oxidative Substrate Flux of Cancer Cells in a Microplate

<div><p>Cancer cells exhibit remarkable alterations in cellular metabolism, particularly in their nutrient substrate preference. We have devised several experimental methods that rapidly analyze the metabolic substrate flux in cancer cells: glycolysis and the oxidation of major fuel substrates glucose, glutamine, and fatty acids. Using the XF Extracellular Flux analyzer, these methods measure, in real-time, the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) of living cells in a microplate as they respond to substrates and metabolic perturbation agents. In proof-of-principle experiments, we analyzed substrate flux and mitochondrial bioenergetics of two human glioblastoma cell lines, SF188s and SF188f, which were derived from the same parental cell line but proliferate at slow and fast rates, respectively. These analyses led to three interesting observations: 1) both cell lines respired effectively with substantial endogenous substrate respiration; 2) SF188f cells underwent a significant shift from glycolytic to oxidative metabolism, along with a high rate of glutamine oxidation relative to SF188s cells; and 3) the mitochondrial proton leak-linked respiration of SF188f cells increased significantly compared to SF188s cells. It is plausible that the proton leak of SF188f cells may play a role in allowing continuous glutamine-fueled anaplerotic TCA cycle flux by partially uncoupling the TCA cycle from oxidative phosphorylation. Taken together, these rapid, sensitive and high-throughput substrate flux analysis methods introduce highly valuable approaches for developing a greater understanding of genetic and epigenetic pathways that regulate cellular metabolism, and the development of therapies that target cancer metabolism.</p></div

Assaying glutamine oxidation and demonstrating transaminase pathway activity.

<p>A. Schematic illustration of biochemical pathway for glutamine oxidation in the mitochondria. B. Kinetic OCR response in SF188f cells to glutamine (4 mM). SF188f cells were plated at 20,000 cells/well in XF24 cell culture plates 24–28 hours prior to the assays. The assay medium was the substrate-free base medium. The OCR value was not normalized. A representative experiment out of three is shown here. Each data point represents mean ± SD, n = 4. C. OCR response (% of baseline) in SF188f cells to glutamine (4 mM) and AOA (100 µM). Glutamine-induced OCR reached 60% over the baseline (OCR at measurement 6 divided by that at measurement 3) while AOA addition reduced it to 20% (OCR at Measurement 9 divided by measurement 3). SF188f cells were plated at 20,000 cells/well in XF24 V7 cell culture plates 24–28 hours before the assays. The % OCR was plotted using measurement 3 as the baseline. The assay medium was the substrate-free base medium. A representative experiment out of three is shown here. Each data point represents mean ± SD, n = 4.</p

Analyzing Glycolytic flux.

<p>A. Schematic illustration of the glycolytic pathway. NADH produced in the cytosol as glucose is converted to pyruvate and is regenerated by LDH in the cytosol. B. Kinetic ECAR response of SF188s cells to glucose (10 mM) and 2-DG (100 mM) or oxamate (100 mM), respectively. SF188s cells were plated at 30,000 cells/well in XF24 V7 cell culture plates 24–28 hours prior to the assays. The assay medium was substrate-free base medium (as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109916#s2" target="_blank">Material and Methods</a>) supplemented with 2 mM glutamine. The ECAR value was not normalized. A representative experiment out of at least three is shown here. Each data point represents mean ± SD, n = 4. C. ECAR response of HeLa cells to glucose (10 mM), 2-DG (100 mM) and antimycin (1 µM). Insert: the OCR response in the same experiments showing the Crabtree effect and that glucose did not increase OCR. HeLa cells were plated at 30,000/well in XF24 cell culture plates 24–28 hours prior to the assays. ECAR or OCR values were not normalized. The assay medium was substrate-free base medium (as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109916#s2" target="_blank">Material and Methods</a>) supplemented with 2 mM glutamine. A representative experiment out of at least three is shown here. Each data point represents mean ± SD, n = 5.</p

Alignment of the amino acid sequences deduced from the fragments cloned from resistant JH-del and susceptible JHS strains with the reported Voltage-gated sodium channel gene sequences from <i>Drosophila melanogaster</i> (D.m), <i>Bombyx mori</i> (B.m), <i>Anopheles gambiae</i> (A.g).

<p>The numbers (1, 2, 3, 4 and 5) denoted the reported mutation positions (M918T, L925I, T929I, L932F and L1014F). The predicted transmembrane domains are marked with asterisks. The amino acid substitution identified in JH-del and JHS were highlighted in black. </p