gebhart/patrepeval huggingface dataset:
Magnetic transition, long-range order, and moment fluctuations in the pyrochlore iridate Eu2Ir2O7 (2011)

Muon spin rotation and relaxation experiments in the pyrochlore iridate Eu2Ir2O7 yield a well-defined muon spin precession frequency below the metal-insulator/antiferromagnetic transition temperature TM = 120 K, indicative of long-range commensurate magnetic order and thus ruling out quantum spin liquid and spin-glass-like ground states. The dynamic muon spin relaxation rate is temperature-independent between 2 K and ~TM and yields an anomalously long Ir^{4+} spin correlation time, suggesting a singular density of low-lying spin excitations. Similar behavior is found in other pyrochlores and geometrically frustrated systems, but also in the unfrustrated iridate BaIrO3. Eu2Ir2O7 may be only weakly frustrated; if so, the singularity might be associated with the small-gap insulating state rather than frustration.
Proverb (1885)

Journal Article Proverb Get access Anon Anon Search for other works by this author on: Oxford Academic Google Scholar Notes and Queries, Volume s6-XII, Issue 291, 25 July 1885, Page 67, https://doi.org/10.1093/nq/s6-XII.291.67b Published: 25 July 1885
Evaluation in Rhesus Macaques of Tat and Rev-Targeted Immunization as a Preventive Vaccine against Mucosal Challenge with SHIV-BX08 (2002)

Recent evidence suggests that a CD8-mediated cytotoxic T-cell response against the regulatory proteins of human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) may control infection after pathogenic virus challenge. Here, we evaluated whether vaccination with Tat or Tat and Rev could significantly reduce viral load in nonhuman primates. Rhesus macaques were primed with Semliki forest Virus (SFV) expressing HIV-1 tat (SFV-tat) and HIV-1 rev (SFV-rev) and boosted with modified vaccinia virus Ankara (MVA) expressing tat and rev. A second group of monkey was primed with SFV-tat only and boosted with MVA-tat. A third group received a tat and rev DNA/MVA prime-boost vaccine regimen. Monitoring of anti-Tat and anti-Rev antibody responses or antigen-specific IFN-gamma production, as measured by enzyme-linked immunospot assays revealed no clear differences between the three groups. These results suggest that priming with either DNA or SFV seemed to be equivalent, but the additive or synergistic effect of a rev vaccine could not be clearly established. The animals were challenged by the rectal route 9 weeks after the last booster immunization, using 10 MID(50) of a SHIV-BX08 stock. Postchallenge follow-up of the monkeys included testing seroconversion to Gag and Env antigens, measuring virus infectivity in PBMC by cocultivation with noninfected human cells, and monitoring of plasma viral load. None of the animals was protected from infection as assessed by PCR, but peak viremia was reduced more than 200-fold compared to sham controls in one third (6/18) of vaccinated macaques, whatever the vaccine regimen they received. Interestingly, among these six protected animals four did not seroconvert. Altogether, these results clearly indicated that the addition of early HIV proteins like Tat and Rev in a multicomponent preventive vaccine including structural proteins like Env or Gag may be beneficial in preventive vaccinal strategies.
A new automated method for the segmentation and characterization of breast masses on ultrasound images (2009)

Segmentation is one of the first steps in most computer-aided diagnosis systems for characterization of masses as malignant or benign. In this study, the authors designed an automated method for segmentation of breast masses on ultrasound (US) images. The method automatically estimated an initial contour based on a manually identified point approximately at the mass center. A two-stage active contour method iteratively refined the initial contour and performed self-examination and correction on the segmentation result. To evaluate the method, the authors compared it with manual segmentation by two experienced radiologists (R1 and R2) on a data set of 488 US images from 250 biopsy-proven masses (100 malignant and 150 benign). Two area overlap ratios (AOR1 and AOR2) and an area error measure were used as performance measures to evaluate the segmentation accuracy. Values for AOR1, defined as the ratio of the intersection of the computer and the reference segmented areas to the reference segmented area, were 0.82 +/- 0.16 and 0.84 +/- 0.18, respectively, when manually segmented mass regions by R1 and R2 were used as the reference. Although this indicated a high agreement between the computer and manual segmentations, the two radiologists' manual segmentation results were significantly (p < 0.03) more consistent, with AOR1 = 0.84 +/- 0.16 and 0.91 +/- 0.12, respectively, when the segmented regions by R1 and R2 were used as the reference. To evaluate the segmentation method in terms of lesion classification accuracy, feature spaces were formed by extracting texture, width-to-height, and posterior shadowing features based on either automated computer segmentation or the radiologists' manual segmentation. A linear discriminant analysis classifier was designed using stepwise feature selection and two-fold cross validation to characterize the mass as malignant or benign. For features extracted from computer segmentation, the case-based test A(z) values ranged from 0.88 +/- 0.03 to 0.92 +/- 0.02, indicating a comparable performance to those extracted from manual segmentation by radiologists (A(z) value range: 0.87 +/- 0.03 to 0.90 +/- 0.03).
Site-Directed Mutagenesis and X-ray Crystallography of the PQQ-Containing Quinoprotein Methanol Dehydrogenase and Its Electron Acceptor, Cytochrome cL, (2001)

Two proteins specifically involved in methanol oxidation in the methylotrophic bacterium Methylobacterium extorquens have been modified by site-directed mutagenesis. Mutation of the proposed active site base (Asp303) to glutamate in methanol dehydrogenase (MDH) gave an active enzyme (D303E-MDH) with a greatly reduced affinity for substrate and with a lower activation energy. Results of kinetic and deuterium isotope studies showed that the essential mechanism in the mutant protein was unchanged, and that the step requiring activation by ammonia remained rate limiting. No spectrally detectable intermediates could be observed during the reaction. The X-ray structure, determined to 3 A resolution, of D303E-MDH showed that the position and coordination geometry of the Ca2+ ion in the active site was altered; the larger Glu303 side chain was coordinated to the Ca2+ ion and also hydrogen bonded to the O5 atom of pyrroloquinoline quinone (PQQ). The properties and structure of the D303E-MDH are consistent with the previous proposal that the reaction in MDH is initiated by proton abstraction involving Asp303, and that the mechanism involves a direct hydride transfer reaction. Mutation of the two adjacent cysteine residues that make up the novel disulfide ring in the active site of MDH led to an inactive enzyme, confirming the essential role of this remarkable ring structure. Mutations of cytochrome c(L), which is the electron acceptor from MDH was used to identify Met109 as the sixth ligand to the heme.
Differential impact of a dyskeratosis congenita mutation in TPP1 on mouse hematopoiesis and germline (2021)

ABSTRACT Telomerase extends chromosome ends in somatic and germline stem cells to ensure continued proliferation. Mutations in genes critical for telomerase function result in telomeropathies such as dyskeratosis congenita (DC), frequently resulting in spontaneous bone marrow failure. While knockout of telomerase in mice has been instrumental in highlighting the importance of telomere length maintenance at an organismal level, it may not be representative of human telomeropathy mutations in vivo . A DC mutation in the shelterin protein TPP1 (K170Δ) that compromises telomerase recruitment to telomeres but leaves other functions of TPP1 and the integrity of the telomerase holoenzyme intact is a physiologically relevant tool to evaluate telomerase-dependent telomere length maintenance in mice. We used CRISPR-Cas9 to generate a mutant mouse knocked in for the equivalent of the TPP1 K170Δ mutation (TPP1 K82Δ) and investigated both its bone marrow and germline compartments in unprecedented detail. TPP1 K82Δ caused progressive telomere erosion with increasing generation number but did not induce steady-state hematopoietic defects. Strikingly, K82Δ caused mouse infertility, consistent with gross morphological defects in the testis and sperm, the appearance of either empty or severely disorganized seminiferous tubules, and a decrease in both spermatogonia and spermatocytes. It is intriguing that both TPP1 K82Δ mice and previously characterized telomerase knockout mice show no spontaneous bone marrow failure but rather succumb to a robust infertility phenotype at steady state. We speculate that telomere length maintenance contributes differently to the evolutionary fitness of humans and mice. Telomere length maintenance in the human bone marrow can ensure progression to reproductive age, while that in the mouse germline can help meet the elevated demand for sperm to produce multiple offspring.
Mechanistic Study of Alkene Hydrosilylation Catalyzed by a β-Dialdiminate Cobalt(I) Complex (2020)

Alkene hydrosilylation is a large-scale process that typically uses precious-metal catalysts. A new generation of highly selective catalysts is based on inexpensive metals, which may have a high-spin electronic configuration and thus may follow novel mechanistic pathways. Here, we describe mechanistic studies on a high-spin cobalt(I) catalyst that performs rapid and regioselective alkene hydrosilylation. Using 1-hexene and PhSiH3 as substrates, we elucidate features of the rate law, test for free radical intermediates with radical clock substrates, and use deuterium substitution to provide mechanistic insight. The resting state has PhSiH3 bound η6 through the phenyl group and evolves over the course of the reaction from a substrate-bound form to a product-bound form. This complicates analysis by variable time normalization analysis (VTNA) because the dependence of the rate on [PhSiH3] is not constant throughout the reaction. Despite this challenge, the accumulated results are consistent with initial oxidative addition of PhSiH3, followed by alkene binding, and then insertion through the Chalk–Harrod or modified Chalk–Harrod mechanism to form the hydrosilylation product. Though the catalyst has a paramagnetic metal center, none of the data implicate radicals participating in the mechanism, and a conventional electron-pair mechanism is most consistent.
Starvation induces rapid degradation of selective autophagy receptors by endosomal microautophagy (2018)

It is not clear to what extent starvation-induced autophagy affects the proteome on a global scale and whether it is selective. In this study, we report based on quantitative proteomics that cells during the first 4 h of acute starvation elicit lysosomal degradation of up to 2-3% of the proteome. The most significant changes are caused by an immediate autophagic response elicited by shortage of amino acids but executed independently of mechanistic target of rapamycin and macroautophagy. Intriguingly, the autophagy receptors p62/SQSTM1, NBR1, TAX1BP1, NDP52, and NCOA4 are among the most efficiently degraded substrates. Already 1 h after induction of starvation, they are rapidly degraded by a process that selectively delivers autophagy receptors to vesicles inside late endosomes/multivesicular bodies depending on the endosomal sorting complex required for transport III (ESCRT-III). Our data support a model in which amino acid deprivation elicits endocytosis of specific membrane receptors, induction of macroautophagy, and rapid degradation of autophagy receptors by endosomal microautophagy.
Schemes for increased output-voltage swing from operational amplifiers (1977)

Two schemes which increase the output-voltage swing of an operational amplifier are presented. It is shown that the schemes may also give a small increase in the low-frequency gain, but they do not improve the slew-rate limit of the amplifier, as previously thought, without reducing the phase margin and degrading the transient response.
Application of a computer dairy model on-farm (1993)

For Mr Barry Garrity, Carterton dairy farmer, the spring of 1992 brought a very challenging decision-making process. A computerised simulator (model) of the physical functions of his property had been in use since October 199 1. As a high stocking rate, high performance farm the next step in improving profitability was being sought. The simulator provided a means of reviewing performance, searching out means of more efficient use of pasture and overcoming the limitations to increased production. The software (UDDER) models grass growth and animal performance for an actual season with a gross margin used to reflect the financial component. In this case base data were derived from the 1990191 season, a record year for the property. Keywords: computer, dairy farm, forecast, gross margin, model, simulator
Silizium und Silikate (2012)

Dieses Kapitel beinhaltet: Silikate Silizium, Herstellung und Eigenschaften Silizium-Anwendungen Was wäre wenn? Literatur
Single Crystal Structure Analysis (2019)

Abstract Single crystal X‐ray structure analysis can be thought of as a particular method limited to experts because of the misconception that it requires expertise and crystallographic knowledge. This was true until the 1990s. However, the reality is even novices to single crystal structure analysis can take advantage of the dependability of this analytical technique just like using other spectroscopic methods due to the recent development of software and hardware. Modern instruments simultaneously perform data collection, processing, and automated structure analysis. This article introduces the overall aspect of single crystal analysis from data collection to structure validation. Emphasis is put on common four topics: mounting a fragile crystal, instrumentation, disordered structure, twin, and absolute structure determination. In the end, the latest topic section refers to the crystalline sponge method that can be summarized as single crystal X‐ray structure analysis without a single crystal.
Synthesen und Untersuchungen von [Oxazolo[2,3‐a]isoindol‐9b(2H)‐yl]phosphonaten und ‐phosphinaten: Eine neue Klasse von Heterocyclen (1993)

Syntheses and Investigations of [Oxazolo[2,3‐ a ]isoindol‐9b(2 H )‐yl]phosphonates and ‐phosphinates: a New Class of Heterocycles We attempted to synthesize diethyl (1‐methyl‐2‐phthalimidoethyl)phosphonate ( 14a ) in a Michaelis‐Becker reaction using diethyl sodiophosphonate ( 13 ) and the tosylate 12a of (2‐hydroxypropyl)phthalimide as starting materials. Instead of TsO substitution in 12a by the nucleophile 13 , the carbonyl C‐atom of the phthalimido moiety was attacked by 13 , followed by an intramolecular nucleophilic substitution at C(2) of the side chain leading to the (oxazolo[2,3‐ a ]isoindolyl)phosphonate 15a ( Scheme 1 ). Similarly, 12a and N ‐(2‐bromoethyl)phthalimide ( 12b ) reacted with butyl (benzene)sodiophosphinate ( 18 ) to the (oxazolo[2,3‐ a ]isoindolyl)(phenyl)phosphinates 20a and 20b , respectively ( Scheme 2 ). The attempt to synthesize enantiomerically pure 2‐substituted (2‐phthalimidoethyl)phosphonates 27 starting from L ‐α‐amino‐acids failed, too ( Scheme 3 ): the main products of the reaction of the N , N ‐phthaloyl‐ O 1 ‐tosyl‐ L ‐aminoalcohols 25a–d with 13 were the 3‐substituted (oxazolo[2,3‐ a ]isoindolyl)‐phosphonates 26a–d , the desired 27b and 27c being observed as by‐products in the 31 P‐NMR spectrum.
EXPERIENCE THE RELEVANCE OF TESTING IN ENGINEERING DESIGN EDUCATION (2014)

Engineering design education imparts students how to Conceive, Design, Implement and Operate complex engineering systems. The „Innovation Project“ at ETH Zurich is a projectbased engineering design course, where 456 undergraduate students of mechanical engineering experience the CDIO activities in the freshman year in teams of 4 to 6 students. Starting from an idea, a concept and a design, the project work includes the production of several prototypes with direct manufacturing technologies and the implementation of the final system in a defined operation environment. A main finding of the project in 2013 is that systems being tested at different stages of the product development process showed higher reliability and better performance in the final contest. As a consequence, the learning effects of testing have considerable impact on the projects’ success. This paper shows how the relevance of testing can be experienced in project-based engineering design education focusing on the case study of the “Innovation Project” where testing is approached in all four CDIO activities: (1) Testing in Conceiving by the development of low-fidelity prototypes facilitates the exploration of ideas and the verification of the concept. (2) Testing in Design enables the students to identify errors such as part collisions primarily in the context of Computer Aided Design. (3) Testing the Implementation refers to testing the assembly of the parts. Finally, (4) Testing for Operation is conducted by integrating the system in the intended overall system. Based on the results, it is discussed how the relevance of testing can be experienced and imparted in project based engineering design classes.
Reduction of Interfacial Resistance between LiMn2O4 and Thio-LISICON (2010)

Abstract not Available.
Perylene Tetracarboxydiimide as an Electron Acceptor in Organic Solar Cells: A Study of Charge Generation and Recombination (2009)

We study charge generation and recombination in organic solar cells that utilize perylene tetracarboxydiimide (PDI) as an electron acceptor and a conjugated polymer as an electron donor. PDI is a promising electron acceptor because of its strong red absorption, LUMO well placed to accept electrons from many conjugated polymers, and good electron mobility. However, we find that, when PDI is finely dispersed in a conjugated polymer, the device efficiency is severely limited by very fast bimolecular charge recombination and that, when the blend is made coarser, the device efficiency becomes limited instead by PDI excitons quickly relaxing into stabilized intermolecular states between PDI molecules rather than undergoing charge transfer. The intramolecular PDI states formed are the same as those observed in PDI blended with poly(styrene) and have lower energy and mobility than the exciton. The two loss channels, that is, bimolecular recombination when charge transfer is fast and reduced charge transfer due to intermolecular state formation when charge transport is better, mean that quantum efficiency may always be low in organic solar cells utilizing PDI unless modification of the PDI can suppress the rate of intermolecular state formation without compromising charge-transport properties. Our results are based on detailed, bias-dependent transient-absorption experiments which also reveal the carrier mobility and internal quantum efficiency (as a function of field) directly in the operating organic solar cells.
Variants associated with HHIP expression have sex-differential effects on lung function (2020)

<ns4:p> <ns4:bold>Background:</ns4:bold> Lung function is highly heritable and differs between the sexes throughout life. However, little is known about sex-differential genetic effects on lung function. We aimed to conduct the first genome-wide genotype-by-sex interaction study on lung function to identify genetic effects that differ between males and females. </ns4:p> <ns4:p> <ns4:bold>Methods:</ns4:bold> We tested for interactions between 7,745,864 variants and sex on spirometry-based measures of lung function in UK Biobank (N=303,612), and sought replication in 75,696 independent individuals from the SpiroMeta consortium. </ns4:p> <ns4:p> <ns4:bold>Results:</ns4:bold> Five independent single-nucleotide polymorphisms (SNPs) showed genome-wide significant (P&lt;5x10 <ns4:sup>-8</ns4:sup> ) interactions with sex on lung function, and 21 showed suggestive interactions (P&lt;1x10 <ns4:sup>-6</ns4:sup> ). The strongest signal, from rs7697189 (chr4:145436894) on forced expiratory volume in 1 second (FEV <ns4:sub>1</ns4:sub> ) (P=3.15x10 <ns4:sup>-15</ns4:sup> ), was replicated (P=0.016) in SpiroMeta. The C allele increased FEV <ns4:sub>1</ns4:sub> more in males (untransformed FEV <ns4:sub>1</ns4:sub> β=0.028 [SE 0.0022] litres) than females (β=0.009 [SE 0.0014] litres), and this effect was not accounted for by differential effects on height, smoking or pubertal age. rs7697189 resides upstream of the hedgehog-interacting protein ( <ns4:italic>HHIP</ns4:italic> ) gene and was previously associated with lung function and <ns4:italic>HHIP</ns4:italic> lung expression. We found <ns4:italic>HHIP</ns4:italic> expression was significantly different between the sexes (P=6.90x10 <ns4:sup>-6</ns4:sup> ), but we could not detect sex differential effects of rs7697189 on expression. </ns4:p> <ns4:p> <ns4:bold>Conclusions:</ns4:bold> We identified a novel genotype-by-sex interaction at a putative enhancer region upstream of the <ns4:italic>HHIP</ns4:italic> gene. Establishing the mechanism by which <ns4:italic>HHIP</ns4:italic> SNPs have different effects on lung function in males and females will be important for our understanding of lung health and diseases in both sexes. </ns4:p>
Negative Regulation of Mitotic Promoting Factor by the Checkpoint Kinase Chk1 in Simian Virus 40 Lytic Infection (2002)

Lytic infection of African green monkey kidney (CV-1) cells by simian virus 40 (SV40) is characterized by stimulation of DNA synthesis leading to bypass of mitosis and replication of cellular and viral DNA beyond a 4C DNA content. To define mechanisms underlying the absence of mitosis, the expression levels of upstream regulatory molecules of mitosis-promoting factor (MPF) were compared in parallel synchronized cultures of SV40-infected and uninfected CV-1 cells. The DNA replication/damage checkpoint kinase Chk1 was phosphorylated in both uninfected and SV40-infected cultures arrested at G(1)/S by mimosine, consistent with checkpoint activation. Following release of uninfected cultures from G(1)/S, Chk1 phosphorylation was lost even though Chk1 protein levels were retained. In contrast, G(1)/S-released SV40-infected cultures exhibited dephosphorylation of Chk1 in S phase, followed by an increase in Chk1 phosphorylation coinciding with entry of infected cells into >G(2). Inhibitors of Chk1, UCN-01 and caffeine, induced mitosis and abnormal nuclear condensation and increased the protein kinase activity of MPF in SV40-infected CV-1 cells. These results demonstrate that SV40 lytic infection triggers components of a DNA damage checkpoint pathway. In addition, chemical inhibition of Chk1 activity suggests that Chk1 contributes to the absence of mitosis during SV40 lytic infection.