485 research outputs found
Exploring differences between average and critical engineering changes: Survey results from Denmark
Portable inhalation systemfor a dosed insulin supply
Интенсивная инсулинотерапия необходима для контроля состояния пациентов с диабетом.Несмотря на постоянное усовершенствование инсулинотерапии, все ещ? существует проблема неудобства режимов многократных инъекций инсулина. Целью данной работы является создание системы, позволяющей осуществлять ингаляцию инсулина.Intensive insulin therapy is necessary for the control of a condition diabetic patients. Despite the constant improvement of insulin therapy, there is still the problem of discomfort repeated regimes of insulin injections. The objective of this work is to create a system that allows the inhalation of insulin
Evidence for the compartmentation of pyruvate metabolism in perfused rat skeletal muscle
Exploring differences between average and critical engineering changes : survey results from Denmark
Change or modification has always been a fundamental part of engineering design. Changes to a design are the rule and not the exception [Clark & Fujimoto 1991]. Engineering changes (ECs), as Jarratt et al. [2005] describe, are alterations made to parts, drawings or software that have already been released during the design process. Over the past decades, engineering change management has gained prominence in engineering design and product development literature, with a number of in-depth case studies (e.g. [Clarkson et al. 2004; Fricke et al. 2000; Giffin et al. 2009; Jarratt et al. 2010; Lindemann & Reichwald 1998; Loch & Terwiesch 1999; Vianello & Ahmed-Kristensen 2011]), industry surveys (e.g. [Deubzer et al. 2005; Huang & Mak 1999; Huang et al. 2003]), and reviews (e.g. [Ahmad et al. 2011; Jarratt et al. 2010; Wright 1997]). Researchers describe and analyse a number of aspects of changes, such as characterisations of changes, causes, initiators, objectives, effects, and potential strategies, and software support to anticipate and handle changes. Studying characterisations of changes, some investigate late engineering changes (e.g. [Coughlan 1992]), others describe strategies to detect avoidable and to cope with unavoidable changes [Fricke et al. 2000], yet others characterise initiated design changes and the associated emergent modifications according to their development over time and potential effects on implementation within the allotted amount of time forming ripple, blossom, or avalanche patterns [Eckert et al. 2004]. Whilst differing in terms of focus and research design what all studies have in common is differentiating between engineering changes for better understanding of patterns of change, ultimately better to manage engineering changes. In this paper, we aim to continue this line of investigation and - examine differences between average and critical changes according to results from a survey with industry participants, and thereby - explore as to what makes changes critical. In this paper, we focus our description on results from an industry survey. With this in mind, the remainder of the paper is structured as follows: Section 2 describes in brief what motivated criticality of engineering changes as the research focus of this paper and outlines the data acquisition and analysis procedure. We present results of this study in Section 3. Section 4 summarises contributions and concludes with suggestions for further work
Electronic transport calculations for rough interfaces in Al, Cu, Ag, and Au
We present results of electronic structure and transport calculations for
metallic interfaces, based on density functional theory and the non-equilibrium
Green's functions method. Starting from the electronic structure of smooth Al,
Cu, Ag, and Au interfaces, we study the effects of different kinds of interface
roughness on the transmission coefficient and the I-V characteristic. In
particular, we compare prototypical interface distortions, including vacancies
and metallic impurities.Comment: 15 pages, 10 figure
Pathogenic Aβ production by heterozygous PSEN1 mutations is intrinsic to the mutant protein and not mediated by conformational hindrance of wild-type PSEN1
Presenilin-1 (PSEN1) is the catalytic subunit of the intramembrane protease γ-secretase and undergoes endoproteolysis during its maturation. Heterozygous mutations in the PSEN1 gene cause early-onset familial Alzheimer’s disease (eFAD) and increase the proportion of longer aggregation-prone amyloid-β peptides (Aβ42 and/or Aβ43). Previous studies had suggested that PSEN1 mutants might act in a dominant-negative fashion by functional impediment of wild-type PSEN1, but the exact mechanism by which PSEN1 mutants promote pathogenic Aβ production remains controversial. Using dual recombinase-mediated cassette exchange (dRMCE), here we generated a panel of isogenic embryonic and neural stem cell lines with heterozygous, endogenous expression of PSEN1 mutations. When catalytically inactive PSEN1 was expressed alongside the wild-type protein, we found the mutant accumulated as a full-length protein, indicating that endoproteolytic cleavage occurred strictly as an intramolecular event. Heterozygous expression of eFAD-causing PSEN1 mutants increased the Aβ42/Aβ40 ratio. In contrast, catalytically inactive PSEN1 mutants were still incorporated into the γ-secretase complex but failed to change the Aβ42/Aβ40 ratio. Finally, interaction and enzyme activity assays demonstrated the binding of mutant PSEN1 to other γ-secretase subunits, but no interaction between mutant and wild-type PSEN1 was observed. These results establish that pathogenic Aβ production is an intrinsic property of PSEN1 mutants and strongly argue against a dominant-negative effect in which PSEN1 mutants would compromise the catalytic activity of wild-type PSEN1 through conformational effects.This work was supported in part by the Alzheimer Forschung Initiative (grant number 11811 to S. W.) and the Deutsche Forschungsgemeinschaft (German Research Foundation, grant number 494911640 to S. W.).Peer reviewe
Induction of Neuronal Death by Microglial AGE-Albumin: Implications for Alzheimer’s Disease
Advanced glycation end products (AGEs) have long been considered as potent molecules promoting neuronal cell death and contributing to neurodegenerative disorders such as Alzheimer’s disease (AD). In this study, we demonstrate that AGE-albumin, the most abundant AGE product in human AD brains, is synthesized in activated microglial cells and secreted into the extracellular space. The rate of AGE-albumin synthesis in human microglial cells is markedly increased by amyloid-β exposure and oxidative stress. Exogenous AGE-albumin upregulates the receptor protein for AGE (RAGE) and augments calcium influx, leading to apoptosis of human primary neurons. In animal experiments, soluble RAGE (sRAGE), pyridoxamine or ALT-711 prevented Aβ-induced neuronal death in rat brains. Collectively, these results provide evidence for a new mechanism by which microglial cells promote death of neuronal cells through synthesis and secretion of AGE-albumin, thereby likely contributing to neurodegenerative diseases such as AD
"Safe" Coulomb Excitation of 30Mg
We report on the first radioactive beam experiment performed at the recently
commissioned REX-ISOLDE facility at CERN in conjunction with the highly
efficient gamma spectrometer MINIBALL. Using 30Mg ions accelerated to an energy
of 2.25 MeV/u together with a thin nat-Ni target, Coulomb excitation of the
first excited 2+ states of the projectile and target nuclei well below the
Coulomb barrier was observed. From the measured relative de-excitation gamma
ray yields the B(E2; 0+ -> 2+) value of 30Mg was determined to be 241(31)
e2fm4. Our result is lower than values obtained at projectile fragmentation
facilities using the intermediate-energy Coulomb excitation method, and
confirms the theoretical conjecture that the neutron-rich magnesium isotope
30Mg lies still outside the ``island of inversion''
Voluntary exercise can strengthen the circadian system in aged mice
Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2luc/C57BL/6) were studied at one of two ages: 3.5 months (n = 39) and >18 months (n = 72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n = 8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption
Mineralogical and geochemical features of sulfide chimneys from the 49°39′E hydrothermal field on the Southwest Indian Ridge and their geological inferences
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Chinese Science Bulletin 56 (2011): 2828-2838, doi:10.1007/s11434-011-4619-4.During January–May in 2007, the Chinese research cruise DY115-19 discovered an active hydrothermal field at 49°39′E/37°47′S on the ultraslow spreading Southwest Indian Ridge (SWIR). This was also the first active hydrothermal field found along an ultraslow-spreading ridge. We analyzed mineralogical, textural and geochemical compositions of the sulfide chimneys obtained from the 49°39′E field. Chimney samples show a concentric mineral zone around the fluid channel. The mineral assemblages of the interiors consist mainly of chalcopyrite, with pyrite and sphalerite as minor constitunets. In the intermediate portion, pyrite becomes the dominant mineral, with chalcopyrite and sphalerite as minor constitunets. For the outer wall, the majority of minerals are pyrite and sphalerite, with few chalcopyrite. Towards the outer margin of the chimney wall, the mineral grains become small and irregular in shape gradually, while minerals within interstices are abundant. These features are similar to those chimney edifices found on the East Pacific Rise and Mid-Atlantic Ridge. The average contents of Cu, Fe and Zn in our chimney samples were 2.83 wt%, 45.6 wt% and 3.28 wt%, respectively. The average Au and Ag contents were up to 2.0 ppm and 70.2 ppm respectively, higher than the massive sulfides from most hydrothermal fields along mid-ocean ridge. The rare earth elements geochemistry of the sulfide chimneys show a pattern distinctive from the sulfides recovered from typical hydrothermal fields along sediment-starved mid-ocean ridge, with the enrichment of light rare earth elements but the weak, mostly negative, Eu anomaly. This is attributed to the distinct mineralization environment or fluid compositions in this area.This work was supported by the China Ocean Mineral
Resources Research and Development Association Program (DY115-
02-1-01) and the State Oceanic Administration Youth Science Fund
(2010318)
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