Ammonium Fluoride as a Hydrogen-disordering Agent for Ice

The removal of residual hydrogen disorder from various phases of ice with acid or base dopants at low temperatures has been a focus of intense research for many decades. As an antipode to these efforts, we now show using neutron diffraction that ammonium fluoride (NH4F) is a hydrogen-disordering agent for the hydrogen-ordered ice VIII. Cooling its hydrogen-disordered counterpart ice VII doped with 2.5 mol% ND4F under pressure leads to a hydrogen-disordered ice VIII with ~31% residual hydrogen disorder illustrating the long-range hydrogen-disordering effect of ND4F. The doped ice VII could be supercooled by ~20 K with respect to the hydrogen-ordering temperature of pure ice VII after which the hydrogen-ordering took place slowly over a ~60 K temperature window. These findings demonstrate that ND4F-doping slows down the hydrogen-ordering kinetics quite substantially. The partial hydrogen order of the doped sample is consistent with the antiferroelectric ordering of pure ice VIII. Yet, we argue that local ferroelectric domains must exist between ionic point defects of opposite charge. In addition to the long-range effect of NH4F-doping on hydrogen-ordered water structures, the design principle of using topological charges should be applicable to a wide range of other 'ice-rule' systems including spin ices and related polar materials.Comment: 23 pages, 4 figures, 2 table

Ab initio scattering from random discrete charges and its impact on the intrinsic parameter fluctuations in nano-CMOS devices

This thesis is concerned with the Monte Carlo simulation of device parameter variation associated with the discrete nature and random variation of ionized impurity atoms within ultra-small conventional n-MOS devices. In particular, the Monte Carlo method is applied to accurately resolve electron interactions with individual ionized impurity atoms and in so doing capture the variation in impurity scattering associated with randomly configured dopant distributions. To date, variation in transport due to position dependent variation in Coulomb scattering has not received any attention although is expected to increase the inherent device parameter variation.A detailed methodology for the accurate treatment of Coulomb scattering within the Ensemble Monte Carlo framework is presented and verified. Improvement over existing methodologies is presented with a short-range force model that significantly reduces errors in conservation of energy during short-range attractive interactions compared with models proposed in similar work. Details of the simulated reproduction of bulk mobility are thoroughly presented to validate the method, while to date such detail is not to be found anywhere in the literature.A charge assignment method is developed to be applied to traditional 'continuously' doped regions in order to allow a consistent description of doping charge when combined with 'atomistic' doping assigned via the Cloud-In-Cell scheme. The charge assignment method also represents the only consistent description of electron charge assigned via CIC and the continuous doping charge.Trapping of a single electron in a series of scaled n-channel MOSFETs was studied with the ab initio Coulomb scattering method and is consistently seen to increase the Random Telegraph Signal, associated with the trapping and de-trapping of such charges, when compared with Drift-Diffusion simulations. It is seen that the electrostatic influence of the trapped charge is most prominent at low applied gate voltages where it accounts for nearly 70 - 80% of the total current reduction when including transport variation in devices with channel lengths of 30- \nm. At high gate voltages, transport variation is the dominant factor with the electrostatic impact accounting for only 40 - 60% of the total variation in the same devices.Extending this treatment to an ensemble of atomistic devices, it is seen that the inclusion of transport variations significantly increases the distribution in device parameters and that the transport variation is significantly dependent upon the specific dopant distribution. Within an ensemble of 50 'atomistic' devices, it was seen from Drift-Diffusion simulation that the average current showed a 3.0% increase over the continuously doped device, while Monte Carlo simulations resulted in a decrease in average current of 1.5%. The standard deviation of the current distribution from Drift-Diffusion simulations was 2.4% while, significantly, Monte Carlo simulations returned a value of 6.7%. This has implications for the published data obtained from Drift-Diffusion simulations which will underestimate the variation

A Case Study: Examining Biological Sex Differences in a 14-Week Neck Strength Protocol for Optimal Neuromuscular Indicators to Reduce the Incidence of Traumatic Brain Injury

Topics in Exercise Science and Kinesiology Volume 4: Issue 1, Article 9, 2023. The primary aim of this research was to analyze potential biological sex differences to determine if a variation in dynamic and isometric neck strength existed following a 14-week novel neck strengthening protocol. College-aged healthy participants who did not have a previous history of head or neck trauma were recruited for this study. A pre- and post-assessment was conducted to gather initial isometric and dynamic neck strength values. The neck strengthening intervention utilized a novel dynamic neck strength device for 14-weeks. 14-week neck strength protocol used in this study did increase dynamic and isometric neck strength in participants. After analysis, the authors discovered an increased gain in dynamic neck strength in males over females. According to the pre- and post-assessment data, males gained an extra 8.821 lbs/rev of clockwise strength and 8.135 lbs/rev of counterclockwise strength over females. The change over time (COT) values revealed males gained an extra 3.69 lb./rev of rate of force development (RFD) in the clockwise direction and 3.92 lb./rev of rate of force development in the counterclockwise direction. There was no statistical difference in isometric strength gain in males versus females; however, both groups improved. Dynamic and isometric neck strength increased for all participants after the 14-week neck strength protocol. Males exhibited a greater increase in dynamic neck strength. Extra gain in male dynamic neck strength may be due to differences between male and female dynamic neck musculature size, abundance of type II muscle fiber type, or rate of adaptation

Acanthamoeba activates macrophages predominantly through toll-like receptor 4 and MyD88-dependent mechanisms to induce Interleukin IL-12 and IL-6

Acanthamoeba castellanii is a free-living ubiquitous amoeba, with a worldwide distribution, that can occasionally infect humans, causing particularly severe infections in immune compromised individuals. Dissecting the immunology of Acanthamoeba infections has been considered problematic due to the very low incidence of disease despite the high exposure rates. Whilst macrophages are acknowledged as playing a significant role in Acanthamoeba infections little is known about how this facultative parasite influences macrophage activity. Therefore, in this study we investigate the effects of Acanthamoeba on the activation of resting macrophages. Consequently, murine bone marrow derived macrophages were co-cultured with trophozoites of either the laboratory Neff strain, or a clinical isolate of A. castellanii. In vitro real-time imaging demonstrated that trophozoites of both strains often established evanescent contact with macrophages. Both Acanthamoeba strains induced a pro-inflammatory macrophage phenotype characterized by significant production of IL-12 and IL-6. However, macrophages co-cultured with the clinical isolate of Acanthamoeba produced significantly less IL-12 and IL-6 in comparison to the Neff strain. The utilization of macrophages derived from MyD88, TRIF, TLR2, TLR4, TLR2/4 deficient mice indicated that Acanthamoeba-induced pro-inflammatory cytokine production was through MyD88-dependent, TRIF independent, TLR4-induced events. This study shows for the first time the involvement of TLRs, expressed on macrophages in the recognition and response to Acanthamoeba trophozoites

Transcriptional and Proteomic Analysis of a Ferric Uptake Regulator (Fur) Mutant of Shewanella oneidensis: Possible Involvement of Fur in Energy Metabolism, Transcriptional Regulation, and Oxidative Stress

The iron-directed, coordinate regulation of genes depends on the fur (ferric uptake regulator) gene product, which acts as an iron-responsive, transcriptional repressor protein. To investigate the biological function of a fur homolog in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1, a fur knockout strain (FUR1) was generated by suicide plasmid integration into this gene and characterized using phenotype assays, DNA microarrays containing 691 arrayed genes, and two-dimensional polyacrylamide gel electrophoresis. Physiological studies indicated that FUR1 was similar to the wild-type strain when they were compared for anaerobic growth and reduction of various electron acceptors. Transcription profiling, however, revealed that genes with predicted functions in electron transport, energy metabolism, transcriptional regulation, and oxidative stress protection were either repressed (ccoNQ, etrA, cytochrome b and c maturation-encoding genes, qor, yiaY, sodB, rpoH, phoB, and chvI) or induced (yggW, pdhC, prpC, aceE, fdhD, and ppc) in the fur mutant. Disruption of fur also resulted in derepression of genes (hxuC, alcC, fhuA, hemR, irgA, and ompW) putatively involved in iron uptake. This agreed with the finding that the fur mutant produced threefold-higher levels of siderophore than the wild-type strain under conditions of sufficient iron. Analysis of a subset of the FUR1 proteome (i.e., primarily soluble cytoplasmic and periplasmic proteins) indicated that 11 major protein species reproducibly showed significant (P < 0.05) differences in abundance relative to the wild type. Protein identification using mass spectrometry indicated that the expression of two of these proteins (SodB and AlcC) correlated with the microarray data. These results suggest a possible regulatory role of S. oneidensis MR-1 Fur in energy metabolism that extends the traditional model of Fur as a negative regulator of iron acquisition systems

Improving the efficiency of electrochemical CO2 reduction using immobilized manganese complexes

Immobilization of [Mn(bpy)(CO)3Br], (1) and [Mn(bpy(tBu)2)(CO)3Br] (2, where (bpy(tBu)2) = 4,4′-di-tert-butyl-2,2′-bipyridine) in Nafion/multi-walled carbon nanotubes (MWCNT) on glassy carbon yielded highly active electrodes for the reduction of CO2 to CO in aqueous solutions at pH 7. Films incorporating 2 have significantly improved selectivity towards CO2, with CO : H2 ∼ 1 at −1.4 V vs. SCE, exceeding that for the previously reported 1/MWCNT/Nafion electrode. Furthermore, we report the synthesis and subsequent electrochemical characterization of two new substituted Mn(i) bipyridine complexes, [Mn(bpy(COOH)2)(CO)3Br] (3) and [Mn(bpy(OH)2)(CO)3Br] (4) (where (bpy(COOH)2) = 4,4′-di-carboxy-2,2′-bipyridine and (bpy(OH)2) = 4,4′-di-hydroxy-2,2′-bipyridine). Both 3 and 4 were found to have some activity towards CO2 in acetonitrile solutions; however once immobilized in Nafion membranes CO2 reduction was found to not occur at significant levels.</p

Relaxin family peptide receptors in GtoPdb v.2023.1

Relaxin family peptide receptors (RXFP, nomenclature as agreed by the NC-IUPHAR Subcommittee on Relaxin family peptide receptors [23, 119]) may be divided into two pairs, RXFP1/2 and RXFP3/4. Endogenous agonists at these receptors are heterodimeric peptide hormones structurally related to insulin: relaxin-1, relaxin, relaxin-3 (also known as INSL7), insulin-like peptide 3 (INSL3) and INSL5. Species homologues of relaxin have distinct pharmacology and relaxin interacts with RXFP1, RXFP2 and RXFP3, whereas mouse and rat relaxin selectively bind to and activate RXFP1 [260]. relaxin-3 is the ligand for RXFP3 but it also binds to RXFP1 and RXFP4 and has differential affinity for RXFP2 between species [259]. INSL5 is the ligand for RXFP4 but is a weak antagonist of RXFP3. relaxin and INSL3 have multiple complex binding interactions with RXFP1 [267] and RXFP2 [132] which direct the N-terminal LDLa modules of the receptors together with a linker domain to act as a tethered ligand to direct receptor signaling [262]. INSL5 and relaxin-3 interact with their receptors using distinct residues in their B-chains for binding, and activation, respectively [321, 152]

A–C Estrogens as Potent and Selective Estrogen Receptor-Beta Agonists (SERBAs) to Enhance Memory Consolidation under Low-Estrogen Conditions

Estrogen receptor-beta (ERβ) is a drug target for memory consolidation in postmenopausal women. Herein is reported a series of potent and selective ERβ agonists (SERBAs) with in vivo efficacy that are A–C estrogens, lacking the B and D estrogen rings. The most potent and selective A–C estrogen is selective for activating ER relative to seven other nuclear hormone receptors, with a surprising 750-fold selectivity for the β over α isoform and with EC50s of 20–30 nM in cell-based and direct binding assays. Comparison of potency in different assays suggests that the ER isoform selectivity is related to the compound’s ability to drive the productive conformational change needed to activate transcription. The compound also shows in vivo efficacy after microinfusion into the dorsal hippocampus and after intraperitoneal injection (0.5 mg/kg) or oral gavage (0.5 mg/kg). This simple yet novel A–C estrogen is selective, brain penetrant, and facilitates memory consolidation