Energetic Shift Research Articles

Memantine shifts cancer cell metabolism via AMPK1/2 mediated energetic switch in A549 lung cancer cells.

Memantine is used to prevent glutamate-mediated excitotoxicity and neurodegeneration in Alzheimer's disease. As glutamine is one of the major source of anabolism in fast growing cancer cells, we aimed to interfere with the cancer cell metabolism in A549 lung cancer cells by using memantine. The effects of memantine on cell cycle progression and cell death in A549 cells were assessed by MTT assay and PI staining. Cells were treated with 0.25 mM memantine for 48 hours and then cell metabolism (AMPKA1, AMPKA2, HIF1A, B-catenin, PKM), apoptosis (p53, p21, Bax, Bcl-XL, NOXA, PUMA) and autophagy related (LC3B-I, LC3B-II, SQSTM1) mRNA and protein expressions were investigated by RT-qPCR and western blotting. Memantine decreased cell viability significantly in a concentration-dependent manner by inducing G0/G1 cell cycle arrest. Our results suggest that memantine activates AMPK1/2 significantly (p=0.039 and p=0.0105) that led cells through apoptosis and autophagy by decreasing cancer cell metabolism regulators like HIF1A, B-catenin and PKM as the consequence of this energetic shift. Memantine represents a useful tool to target metabolism in cancer cells. Therefore, it might be used a new repurposed drug in cancer treatment.

Molecular Dynamics Simulations Based on Polarizable Models Show that Ion Permeation Interconverts between Different Mechanisms as a Function of Membrane Thickness.

Different mechanisms have been proposed to explain the permeation of charged compounds through lipid membranes. Overall, it is expected that an ion-induced defect permeation mechanism, where substantial membrane deformations accompany ion movement, should be dominant in thin membranes but that a solubility-diffusion mechanism, where ions partition into the membrane core with large associated dehydration energy costs, becomes dominant in thicker membranes. However, while this physical picture is intuitively reasonable, capturing the interconversion between these two permeation mechanisms in molecular dynamics (MD) simulations based on atomic models is challenging. In particular, simulations relying on nonpolarizable force fields are artificially unfavorable to the solubility-diffusion mechanism, as induced polarization of the nonpolar hydrocarbon is ignored, causing overestimated free energy costs for charged molecules to enter into this region of the membrane. In this study, all-atom MD simulations based on nonpolarizable and polarizable force fields are used to quantitatively characterize the permeation process for the arginine side chain analog methyl-guanidinium through bilayer membranes of mono-unsaturated phosphatidylcholine lipids with and without cholesterol, resulting in thicknesses spanning from ∼24 to ∼42 Å. With simulations based on a nonpolarizable force field, ion translocation can take place solely through an ion-induced defect mechanism, with free energy barriers increasing linearly from 14 to 40 kcal/mol, depending on the thickness. However, with simulations based on a polarizable force field, ion translocation is predominantly dominated by an ion-induced defect mechanism in thin membranes, which progressively converts to a solubility-diffusion mechanism as the membranes get thicker. The transition between the two mechanisms occurs at a thickness of ∼29 Å, with lipid tails of 22 or more carbon atoms. This situation appears to represent the upper limit for ion-induced defect permeation within the current polarizable models. Beyond this thickness, it becomes energetically preferable for the ion to dehydrate and partition into the membrane core-a phenomenon that cannot be captured using the nonpolarizable models. Induced electronic polarizability therefore leads not just to a shift in permeation energetics but to an interconversion between two strikingly different physical mechanisms. The result highlights the importance of induced polarizability in modeling lipid membranes.

A shock recovery experiment and its implications for Mercury's surface: The effect of high pressure on porous olivine powder as a regolith analog

We conducted classic dynamic high - pressure experiments on porous San Carlos (SC) olivine powder to examine if and how different shock stages modify corresponding reflectance mid – infrared (MIR) spectra. Microscopic investigation of the thin sections produced of our shocked samples indicates local peak pressures of >60 GPa along with all lower grade shock stages. Spectral analyses of optically identified shock areas were documented and compared in terms of Christiansen Feature (CF) and the position of olivine – diagnostic Reststrahlenbands (RBs). We found that one RB (fundamental vibrations of the orthosilicate - ion) of olivine occurring at 980 cm−1 (corresponding to ≈ 10.2 μm) shows the least energetic shift in the investigated MIR spectra and could therefore serve as a proxy for the presence of olivine in remote sensing application. Furthermore, a peak located at ≈ 1060 cm−1 (≈ 9.4 μm) shows a significant intensity change probably related to the degree of shock exposure or grain orientation effects, as we observe a decline in intensity of this band from our averaged reference olivine spectra of our IRIS database (diffuse reflectance measurement) down to spectra of grains showing mosaicism and recrystallized areas. We also report the presence of a weak band in some of the olivine spectra located at ≈ 1100 cm−1 (9.1 μm) that has an influence on the position of the CF when spectral data of olivine are averaged.

Para‐Selective Cyanation of Arenes by H‐Bonded Template

The significance of site selective functionalization stands upon the superior selectivity, easy synthesis and diverse product utility. In this work, we demonstrate the para-selective introduction of versatile nitrile moiety, enabled by a detachable and reusable H-bonded auxiliary. The methodology holds its efficiency irrespective of substrate electronic bias. The conspicuous shift in the step energetics was probed by both experimental and computational mechanistic tools, which heralds the inception of para-deuteration. The synthetic impact of the methodology was highlighted with reusability of directing group and post synthetic modifications.

Low-frequency Raman spectrum of 2D layered perovskites: Local atomistic motion or superlattice modes?

We report the low-frequency Raman spectrum (ω = 10 cm-1-150 cm-1) of a wide variety of alkylammonium iodide based 2D lead halide perovskites (2D LHPs) as a function of A-site cation (MA = methylammonium and FA = formamidinium), octahedral layer thickness (n = 2-4), organic spacer chain length (butyl-, pentyl-, hexyl-), and sample temperature (T = 77 K-293 K). Using density functional theory calculations under the harmonic approximation for n = 2 BA:MAPbI, we assign several longitudinal/transverse optical phonon modes between 30 cm-1 and 100 cm-1, the eigendisplacements of which are analogous to that observed previously for octahedral twists/distortions in bulk MAPbI. Additionally, we propose an alternative assignment for low-frequency modes below this band (<30 cm-1) as zone-folded longitudinal acoustic phonons corresponding to the periodicity of the entire layered structure. We compare measured spectra to predictions of the Rytov elastic continuum model for zone-folded dispersion in layered structures. Our results are consistent across the various 2D LHPs studied herein, with energetic shifts of optical phonons corresponding to microscopic structural differences between materials and energetic shifts of acoustic phonons according to changes in the periodicity and elastic properties of the perovskite/organic subphases. This study highlights the importance of both the local atomic order and the superlattice structure on the vibrational properties of layered 2D materials.

Hard X‐ray photoelectron spectroscopy study of core level shifts at buried GaP/Si(001) interfaces

We present a study of buried GaP/Si(001) heterointerfaces by hard X‐ray photoelectron spectroscopy. Well‐defined thin (4–50 nm) GaP films were grown on Si(001) substrates with 2° miscut orientations by metalorganic vapor phase epitaxy. Core level photoelectron intensities and valence band spectra were measured on heterostructures as well as on the corresponding reference (bulk) substrates. Detailed analysis of core level peaks revealed line broadening and energetic shifts. Valence band offsets were derived for the films with different thickness. Based on the observed variation of the valence band offsets with the GaP film thickness and on the experimental evidence of line broadening, the existence of charge displacement at the GaP/Si(001) interface is suggested.

Protective Role of Mitophagy Associated Metabolic Reprogramming of Peripheral Macrophages During Tuberculosis

Mitophagy, the process of selective clearance of mitochondria in the cells is executed through receptor and adaptor mediated pathways. NIX is crucial for receptor-mediated mitophagy and is not characterized well for its role in host-directed protective immunity against infection. Whole transcriptome analysis of PBMCs from treatment naive (n = 5) and healthy controls (n = 4) showed altered expression of genes mediating mitophagy and cellular energetics pathways. M. tuberculosis infection associated systemic alteration in mitophagy and cellular energetics pathway genes NIX, HADH, LC3C, ECI2 and PFKFB3 in PBMCs from a validation cohort of treatment naive TB patients (n = 22) and healthy controls (n = 22) was in concordance with RNASeq data. Ex-vivo infection of BCG in PBMCs and THP-1 cells also showed increased expression of genes belonging to glycolysis and mitophagy pathways, which was in correlation with decreased uptake of Mito-Tracker Red, increased uptake of 2-NBDG, increased consumption of 100% U-13C6 labelled glucose and production of 100% U-13C3 labelled lactate, indicating a shift in cellular energetics. Following NIX knockdown, the mRNA levels of glycolysis and mitophagy pathway genes were reduced, compared with negative control siRNA. Following NIX knockdown, BCG infected cells consumed less glucose (2-NBDG) and uptake of MitoTracker Red increased. NIX knocks also decreased secretion of inflammatory cytokines (IL-1 β, TNF- α, and IL-6 in macrophages. This study shows that M. tuberculosis infection induces systemic effects, correlating with M1 phenotype associated transition of cellular energetics and induction of receptor-mediated mitophagy. Further studies are required to explore mitophagy mediated treatment intervention for tuberculosis management.

Severe coral loss shifts energetic dynamics on a coral reef

Abstract Declining coral cover and loss of structural complexity are widely reported on today's coral reefs. While coral loss frequently triggers changes in coral reef fish assemblage structure, the ecosystem‐scale consequences of these changes are poorly known. Here we evaluate how four metrics of energy flow and storage that underscore a critical coral reef function, consumer biomass production, respond to severe coral loss on a coral reef in the northern Great Barrier Reef, Australia. We compared fish and benthic surveys at Lizard Island from 2003 to 2004 with surveys in 2018 using an individual‐level modelling approach that integrates growth and mortality coefficients to estimate community‐level standing biomass, productivity, consumed biomass and turnover. In the study period, coral cover declined by 72%–83% in forereef zones while turf cover increased by 18%–100% across all zones. Reef fish assemblages, in turn, responded with a 71% increase in standing biomass, 41% in productivity and 37% in consumed biomass, mainly driven by nominally‐herbivorous fishes (Labridae—Scarini, Acanthuridae and Siganidae). By contrast, biomass turnover rates declined by 19%. Our findings suggest that coral loss can drive energetic shifts on coral reefs, leading to more productive, but slower paced reef fish assemblages. Although the observed build‐up of biomass may appear positive, the decreased turnover rates indicate that the system is unable to maintain biomass replacement levels. This suggests that the enhanced productivity that accompanied coral loss may be driven by storage effects from the somatic growth of individuals already present, questioning the temporal stability of these changes to coral reef ecosystem functioning. A free Plain Language Summary can be found within the Supporting Information of this article.

Role of lipopolysaccharides and lipoteichoic acids on C-Chrysophsin-1 interactions with model Gram-positive and Gram-negative bacterial membranes.

Antimicrobial peptides (AMPs) are attractive as biomaterial coatings because they have broad spectrum activity against different microbes, with a low likelihood of incurring antimicrobial resistance. Direct action against the bacterial membrane is the most common mechanism of action (MOA) of AMPs, with specific MOAs dependent on membrane composition, peptide concentration, and environmental factors that include temperature. Chrysophsin-1 (CHY1) is a broad spectrum salt-tolerant AMP that is derived from a marine fish. A cysteine modification was made to the peptide to facilitate attachment to a surface, such as a biomedical device. The authors used quartz crystal microbalance with dissipation monitoring to study how temperature (23 and 37 °C) and lipid composition influence the MOA of cysteine-modified peptide (C-CHY1) with model membranes comprised of supported lipid bilayers (SLBs). These two temperatures were used so that the authors could better understand the differences in behavior between typical lab temperatures and physiologic conditions. The authors created model membranes that mimicked properties of Gram-negative and Gram-positive bacteria in order to understand how the mechanisms might differ for different types of bacterial systems. SLB models of Gram-positive bacterial membranes were formed using combinations of phosphatidylcholine, phosphatidylglycerol (PG), and S. aureus-derived lipoteichoic acid (LTA). SLB models of Gram-negative bacterial membranes were formed using combinations of phosphatidylethanolamine (PE), PG, and E. coli-derived lipopolysaccharides (LPS). The molecules that distinguish Gram-positive and Gram-negative membranes (LTA and LPS) have the potential to alter the MOA of C-CHY1 with the SLBs. The authors' results showed that the MOA for the Gram-positive SLBs was not sensitive to temperature, but the LTA addition did have an effect. Specifically, similar trends in frequency and dissipation changes across all overtones were observed, and the same mechanistic trends were observed in the polar plots at 23 and 37 °C. However, when LTA was added, polar plots showed an association between C-CHY1 and LTA, leading to SLB saturation. This was demonstrated by significant changes in dissipation, while the frequency (mass) was not increasing after the saturation point. For the Gram-negative SLBs, the composition did not have a significant effect on MOA, but the authors saw more differences between the two temperatures studied. The authors believe this is due to the fact that the gel-liquid crystal transition temperature of PE is 25 °C, which means that the bilayer is more rigid at 23 °C, compared to temperatures above the transition point. At 23 °C, a significant energetic shift would be required to allow for additional AMP insertion. This could be seen in the polar plots, where there was a steep slope but there was very little mass addition. At 37 °C, the membrane is more fluid and there is less of an energetic requirement for insertion. Therefore, the authors observed greater mass addition and fewer changes in dissipation. A better understanding of C-CHY1 MOA using different SLB models will allow for the more rational design of future therapeutic solutions that make use of antimicrobial peptides, including those involving biomaterial coatings.

Doping and interfacial modification of the P3HT/ZnO photovoltaic interface: Insights from density functional theory

In this work, we examine how the properties of the poly-3-hexylthiophene(P3HT)/ZnO solar cell are affected by interfacial modification with phenyl-C61-butyric acid (PCBA) and doping with Sr. Using density functional theory calculations on ideal models of the P3HT/ZnO(101¯0) interface, we characterize the equilibrium structures of the pure and modified interfaces, evaluate their ideal work of separation, and examine the energy level alignments and electronic structure. We find that doping with Sr and introducing PCBA have little impact on interfacial distances and do not strengthen interfacial adhesion. Rather, the individual and cumulative impacts of Sr-doping and PCBA are observed in changes to the energy level alignments, including the open circuit voltage and the energy offset that drives exciton separation. Sr dopants and PCBA cause these energetic shifts through differing effects on the electrostatic potential offset and interfacial dipole moments.

Monarch butterflies reared under autumn‐like conditions have more efficient flight and lower post‐flight metabolism

1. Many migratory animals undergo physiological and behavioural changes to prepare for and sustain long‐distance movements. Because insect migrations are common and diverse, studies that examine how migratory insects meet the energetic demands of long‐distance movements are badly needed.2. Monarch butterflies (Danaus plexippus) migrate up to 4000 km annually from eastern North America to wintering sites in central Mexico. Autumn generation monarchs undergo physiological and behavioural changes in response to environmental cues to initiate migration. In particular, exposure to cooler temperatures and shorter day lengths in early autumn causes monarchs to enter the hormonally induced state of reproductive diapause.3. This study examined differences in flight‐associated metabolic rate (MR) and flight performance metrics for monarchs experimentally reared under autumn‐like conditions (typically experienced before the southward migration) relative to monarchs reared under summer‐like conditions.4. Adult monarchs reared under autumn‐like conditions showed lower post‐flight MRs, greater flight efficiency, and lower measures of reproductive activity relative to monarchs reared under summer‐like conditions. Increases in post‐flight metabolism were associated with monarch body weight, age, and flight velocity.5. These findings suggest that a trans‐generational shift in flight energetics is an important component of the monarch's complex migratory syndrome, and that physiological changes that accompany reproductive diapause facilitate energy conservation during flight.

Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan

To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources. Additionally, dietary tracers were necessary to identify food web influences. Through combined Hg, C, and N stable isotopic analyses, we were able to differentiate between a shift in Hg sources to fish and periods when energetic transitions (from dreissenid mussels) led to the assimilation of contrasting Hg pools (2000 to present). In the late 1980s, lake trout δ202Hg increased (0.4‰) from regulatory reductions in regional Hg emissions. After 2000, C and N isotopes ratios revealed altered food web pathways, resulting in a benthic energetic shift and changes to Hg bioaccumulation. Continued increases in δ202Hg indicate fish are responding to several United States mercury emission mitigation strategies that were initiated circa 1990 and continued through the 2011 promulgation of the Mercury and Air Toxics Standards rule. Unlike archives of sediments, this fish archive tracks Hg sources susceptible to bioaccumulation in Great Lakes fisheries. Analysis reveals that trends in fish Hg concentrations can be substantially affected by shifts in trophic structure and dietary preferences initiated by invasive species in the Great Lakes. This does not diminish the benefits of declining emissions over this period, as fish Hg concentrations would have been higher without these actions.

Suppression of Recombination Losses in Polymer:Nonfullerene Acceptor Organic Solar Cells due to Aggregation Dependence of Acceptor Electron Affinity

AbstractHere, it is investigated whether an energetic cascade between mixed and pure regions assists in suppressing recombination losses in non‐fullerene acceptor (NFA)‐based organic solar cells. The impact of polymer‐NFA blend composition upon morphology, energetics, charge carrier recombination kinetics, and photocurrent properties are studied. By changing film composition, morphological structures are varied from consisting of highly intermixed polymer‐NFA phases to consisting of both intermixed and pure phase. Cyclic voltammetry is employed to investigate the impact of blend morphology upon NFA lowest unoccupied molecular orbital (LUMO) level energetics. Transient absorption spectroscopy reveals the importance of an energetic cascade between mixed and pure phases in the electron–hole dynamics in order to well separate spatially localized electron–hole pairs. Raman spectroscopy is used to investigate the origin of energetic shift of NFA LUMO levels. It appears that the increase in NFA electron affinity in pure phases relative to mixed phases is correlated with a transition from a relatively planar backbone structure of NFA in pure, aggregated phases, to a more twisted structure in molecularly mixed phases. The studies focus on addressing whether aggregation‐dependent acceptor LUMO level energetics are a general design requirement for both fullerene and NFAs, and quantifying the magnitude, origin, and impact of such energetic shifts upon device performance.

Metabolomic Investigation of β-Thalassemia in Chorionic Villi Samples.

Background: Beta-thalassemias are blood disorders characterized by poorly understood clinical phenotypes ranging from asymptomatic to severe anemia. Metabolic composition of the human placenta could be affected by the presence of pathological states such as β-thalassemia. The aim of our study was to describe metabolic changes in chorionic villi samples of fetuses affected by β-thalassemia compared to a control group by applying a metabolomics approach. Methods: Chorionic villi samples were differentiated according to the genetic diagnosis of β-thalassemia: control (Group 1, n = 27); heterozygous (Group 2, n = 7); homozygous (Group 3, n = 7). Gas chromatography–mass spectrometry was used to detect the metabolic composition of the samples. Subsequently, multivariate and univariate statistical analysis was performed. The discriminant metabolites were used to identify the altered pathways. Results: Supervised multivariate models were devised to compare the groups. The model resulting from the comparison between Group 1 and Group 3 was the most significant. Discriminant metabolites were identified, and the most altered pathways were as follows: pentose phosphate pathway (PPP), arachidonic acid metabolism, glycolysis, and gluconeogenesis, suggesting the presence of an energetic shift toward the PPP and the presence of oxidative stress in β-thalassemia chorionic villi samples. Conclusions: The metabolomics approach identified a specific metabolic fingerprint in chorionic villi of fetuses affected by β-thalassemia.

Controlling the Performance of Si(111) Photoelectrodes Via Molecular Modification

The small bandgap of silicon (1.1 eV) and large photocurrent density (~25 mA/cm2 under 100 mW/cm2 illumination) renders silicon a nearly ideal photocathode material for photoelectrochemical hydrogen evolution (PEC-HER). However, freshly etched silicon surfaces are highly unstable and readily react with both air and solution to form chemically amorphous junctions that limit device efficacy. Stabilization of Si(111) by alkylation has resulted in well-passivated and chemically well-defined surfaces. However, the resulting interfacial dipole of the alkylated surface shifts the onset of HER to negative efficiencies, even on Pt decorated surfaces. To this end, our group has explored low-temperature, solution-based processing methods to significantly alter the interfacial properties of Si(111). Chemically derivatized surfaces (R: phenyl, para-nitrophenyl, 9-anthracene, and 9-nitroanthracene) have been achieved using organolithium precursors. Mott-Schottky analysis revealed energetic shifts in the band-edge positions of the surfaces with unity correlation to potential shifts in PEC-HER onset of pSi-R|TiO2|Pt devices. This indicates quantitative control of the photovoltage through molecular design, even in the presence of MOx and catalyst overlayers. In addition, we find that the molecular identity of the modifier plays a significant role in determining rates of surface recombination; we explore this relationship with two model systems: para-nitrophenyl (low surface recombination) and meta-dinitrophenyl (high surface recombination) and develop design principles for retaining high-quality surfaces with low rates of recombination. Finally, we utilized kinetically simple systems (one-electron, outer sphere redox couple) to demonstrate the effects of surface recombination, TiO2 deposition, and Pt deposition on the current-voltage character of these surfaces in the absence of a catalytic overpotential. Without the convoluted kinetics of catalysis, we develop a detailed view of the interfacial energetics of the chemically complex pSi-R|TiO2|Pt junctions.

In vitro and in vivo potential of a blend of essential oil compounds to improve rumen fermentation and performance of dairy cows

The objective of this study was to evaluate in vitro and in vivo potential of a specific commercial blend of essential oil active compounds (BEO) to improve rumen fermentation and general dairy cow performance. First, the main active components of the BEO were identified and quantified. Then, the in vitro experiment was conducted using 24 h batch incubation of buffered rumen fluid. The BEO was added at 0, 20, 100, 200, 600, and 1000 mg/l of culture fluid, with substrate containing forage and concentrate at a ratio of 60:40 dry matter (DM) basis. The concentrations of 600 and 1000 mg/l decreased (P < 0.05) methane production per dry matter incubated (DMi) by 5.7% and 17.1%, respectively, and a concentration of 1000 mg/l decreased ammonia-N concentration by 10.0%. However, these reductions were accompanied by a decrease (P < 0.05) in apparent dry matter disappearance (aDMd), and lowered (P < 0.05) the net production of volatile fatty acids (nVFA) indicating, that there were no beneficial selective inhibitory properties of BEO supplementation. For the in vivo experiment, 30 lactating Holstein cows (two primiparous and 28 multiparous) in mid-lactation were randomly assigned to two treatments. During a 15 week period, cows in the control group (CON; n = 15) were fed the basal diet with no additive, and cows in the other group (BEO; n = 15) received the same diet supplemented with 1.2 g/cow/d BEO. Addition of BEO did not affect (P = 0.218) DM intake and milk yield (P = 0.102). For feed efficiency (P = 0.047) and body weight (P = 0.014), the treatment × time interactions were observed, with cows fed BEO having a lower average feed efficiency and a higher average body weight. BEO treatment tended to decrease the proportion of milk fat (P = 0.072), without affecting other milk quality parameters. BEO supplemented cows had lower VFA concentrations in rumen fluid (P = 0.006), and correspondingly, pH values were higher (P = 0.018). No differences were detected between the treatments for proportions of individual VFA and ammonia-N concentration. The responses of dairy cows on BEO were more pronounced after the 5th week of supplementation. This indicates the necessity of a longer adaptation period than commonly used in studies evaluating the effects of essential oils (EO). Due to energetic shift toward body weight gain additional attention should be paid to the systemic effects of EO. Generally, results from this study suggest that mid-lactation dairy cows did not benefit from being supplemented with BEO.

Metabolic characterization of amniotic fluids of fetuses with enlarged nuchal translucency.

Background In prenatal diagnosis, a thickened nuchal translucency (NT) is one of the most sensitive and specific markers for several defects but it may also be found in 5% of healthy fetuses. The pathophysiological causes that lead to an increase in NT are not yet fully understood. Metabolomics represents a new promising approach, useful for studying different metabolites in biological organisms in response to environmental stressors. The aim of our study was to investigate the metabolomic profile of the amniotic fluid samples (AFS) of euploid fetuses with enlarged nuchal translucency (ENT) compared to a control group (C group). Methods This study was carried out on a group of women who underwent second-trimester amniocentesis for advanced maternal age (C group) or for NT ≥95th percentile (ENT group) found during first-trimester aneuploidy screening. AFS were analyzed with proton nuclear magnetic resonance (1H-NMR) and high-performance liquid chromatography (HPLC), and subsequent multivariate and univariate statistical analyses were conducted, followed by pathway analysis. Results In total, 67 AFS from the C group and 23 from the ENT group were analyzed. Partial least square discriminate analysis was carried out (R2X=0.784, R2Y=0.658, Q2=0.622, P<0.0001). A different metabolic profile was observed in the ENT group compared with the C group, suggesting an energetic shift to a glycolytic phenotype in an oxidative environment in the ENT group compared to the C group. Conclusion Metabolomic studies enable the identification of metabolic alterations occurring in fetuses with ENT. These findings may provide a new basis for better understanding the pathophysiological mechanisms in this prenatal phenomenon.

Influence of the quantum dot geometry on p -shell transitions in differently charged quantum dots

Absorption spectra of neutral, negatively and positively charged semiconductor quantum dots are studied theoretically. We provide an overview of the main energetic structure around the p-shell transitions, including the influence of nearby nominally dark states. Based on the envelope function approximation, we treat the four-band Luttinger theory as well as the direct and short range exchange Coulomb interactions within a configuration interaction approach. The quantum dot confinement is approximated by an anisotropic harmonic potential. We present a detailed investigation of state mixing and correlations mediated by the individual interactions. Differences and similarities between the differently charged quantum dots are highlighted. Especially large differences between negatively and positively charged quantum dots become evident. We present a visualisation of energetic shifts and state mixtures due to changes in size, in-plane asymmetry and aspect ratio. Thereby we provide a better understanding of the experimentally hard to access question of quantum dot geometry effects in general. Our findings show a new method to determine the in-plane asymmetry from photoluminescense excitation spectra. Furthermore, we supply basic knowledge for tailoring the strength of certain state mixtures or the energetic order of particular excited states via changes in the shape of the quantum dot, which is highly interesting e.g. to understand relaxation paths.

The density-of-states contributions to the negative field charge drift mobility effect in poly(3-hexylthiophene) organic semiconductor

The origin of the empirical linear dependence of Eint the electric field at the charge-injecting metal/poly(3-hexylthiophene), P3HT, interfaces on the externally applied bias, Ea, that governs its room temperature negative field charge drift mobility is investigated. The published electrostatic model is modified in the sense that the energetic shift φ of the Gaussian disordered hole and electron energy states is determined to be a linear function of the externally applied electric field, Ea. On this basis the distorted Gaussian shaped interfacial electric field Eint is obtained and the empirical Eint is identified as the linear interpolation function of positive slope through the inflection point of the calculated curve. The disordered energy states extend throughout the P3HT charge transport gap and the populations of interface charges follow unequal Ea dependences. The coupling between the deduced interfacial electric field Eint and the P3HT effective mobility enables the predictions to be compared to the published time-of-flight room temperature negative field drift mobility data of holes and electrons in various metal/P3HT sandwich-type organic structures.

The effectiveness of isometric contractions combined with eccentric – concentric training and simple lumbopelvic control exercises on pain and disability in chronic patellar tendinopathy: A case report

Paleoecological reconstructions of past climate are often based on a single taxonomic group with a consistent presence. Less is known about the relationship between multi-taxon community-wide change and climate variability. Here we reconstruct paleoecological change in a Late Quaternary (16.1–3.4 ka) sediment core from the California margin (418 m below sea level) of Santa Barbara Basin (SBB), USA, using Mollusca (Animalia) and Foraminifera (Rhizaria) microfossils. Building upon previous investigations, we use multivariate ordination and cluster analyses to interpret community-scale changes in these distinctly different taxonomic groups across discrete climate episodes. The strongest differences between seafloor biological communities occurred between glacial (prior to Termination IA, 14.7 ka) and interglacial climate episodes. Holocene communities were well partitioned, indicating that sub-millennial oceanographic variability was recorded by these microfossils. We document strong evidence of chemosynthetic trophic webs and sulfidic environments (from gastropod Alia permodesta and bivalve Lucinoma aequizonata), which characterized restricted intervals previously interpreted as well oxygenated (such as the Pre-Bølling Warming). Mollusc records indicate first-order trophic energetic shifts between detrital and chemosynthetically-fixed carbon. Molluscs associated with widely different physiological preferences occur here within single, decadal intervals of sediment, and as such mollusc assemblages may reflect significant inter-decadal oceanographic variability. Foraminifera assemblages provide exceptional records of the sequential, chronological progression of the deglacial climatic and oceanographic events, whereas mollusc assemblages reflect non-chronological similarities in reoccurring communities. Foraminifera taxa that drive community similarity here are also independently recognized as marker species for seafloor hypoxia regimes, which provides support for the idea that oxygenation change is a principal driver of seafloor environmental variability.