393 research outputs found
Elevated temperature fatigue of TZC MOLYBDENUM alloy under high frequency and high vacuum conditions
Elevated temperature fatigue of TZC molybdenum alloy determined in high frequency and high vacuum test
Does the food ingredient pectin provide a risk for patients allergic to non-specific lipid-transfer proteins?
Pectin, a dietary fiber, is a polysaccharide that is widely used in food industry as a gelling agent. In addition, prebiotic and beneficial immunomodulatory effects of pectin have been demonstrated, leading to increased importance as food supplement. However, as cases of anaphylactic reactions after consumption of pectin-supplemented foods have been reported, the present study aims to evaluate the allergy risk of pectin. This is of particular importance since most of the pectin used in the food industry is extracted from citrus or apple pomace. Both contain several allergens such as non-specific lipid transfer proteins (nsLTPs), known to induce severe allergic reactions, which could impair the use of pectins in nsLTP allergic patients. Therefore, the present study for the first time was performed to analyze residual nsLTP content in two commercial pectins using different detection methods. Results showed the analytical sensitivity was diminished by the pectin structure. Finally, spiking of pectin with allergenic peach nsLTP Pru p 3 led to the conclusion that the potential residual allergen content in both pectins is below the threshold to induce anaphylactic reactions in nsLTP-allergic patients. This data suggests that consumption of the investigated commercial pectin products provides no risk for inducing severe reactions in nsLTP-allergic patients
Synthesis of CdS and CdSe nanocrystallites using a novel single-molecule precursors approach
The synthesis of CdS and CdSe nanocrystallites using the thermolysis of several dithioor
diselenocarbamato complexes of cadmium in trioctylphosphine oxide (TOPO) is reported.
The nanodispersed materials obtained show quantum size effects in their optical spectra
and exhibit near band-edge luminescence. The influence of experimental parameters on
the properties of the nanocrystallites is discussed. HRTEM images of these materials show
well-defined, crystalline nanosized particles. Standard size fractionation procedures can
be performed in order to narrow the size dispersion of the samples. The TOPO-capped CdS
and CdSe nanocrystallites and simple organic bridging ligands, such as 2,2¢-bipyrimidine,
are used as the starting materials for the preparation of novel nanocomposites. The optical
properties shown by these new nanocomposites are compared with those of the starting
nanodispersed materials
Spatial-proteomics reveals phospho-signaling dynamics at subcellular resolution
Dynamic change in subcellular localization of signaling proteins is a general concept that eukaryotic cells evolved for eliciting a coordinated response to stimuli. Mass spectrometry-based proteomics in combination with subcellular fractionation can provide comprehensive maps of spatio-temporal regulation of protein networks in cells, but involves laborious workflows that does not cover the phospho-proteome level. Here we present a high-throughput workflow based on sequential cell fractionation to profile the global proteome and phospho-proteome dynamics across six distinct subcellular fractions. We benchmark the workflow by studying spatio-temporal EGFR phospho-signaling dynamics in vitro in HeLa cells and in vivo in mouse tissues. Finally, we investigate the spatio-temporal stress signaling, revealing cellular relocation of ribosomal proteins in response to hypertonicity and muscle contraction. Proteomics data generated in this study can be explored through https://SpatialProteoDynamics.github.io
First measurement of the Gerasimov-Drell-Hearn integral for Hydrogen from 200 to 800 MeV
A direct measurement of the helicity dependence of the total photoabsorption
cross section on the proton was carried out at MAMI (Mainz) in the energy range
200 < E_gamma < 800 MeV. The experiment used a 4 detection system, a
circularly polarized tagged photon beam and a frozen spin target.
The contributions to the Gerasimov-Drell-Hearn sum rule and to the forward
spin polarizability determined from the data are 226 \pm 5 (stat)\pm
12(sys) \mu b and -187 \pm 8 (stat)\pm 10(sys)10^{-6} fm^4, respectively, for
200 < E_\gamma < 800 MeV.Comment: 6 pages, 3 figures, 3 table
Up-regulation of NMDA receptor subunit and post-synaptic density protein expression in the thalamus of elderly patients with schizophrenia
Numerous studies have described structural and functional abnormalities of the thalamus in schizophrenia, but surprisingly few studies have examined neurochemical abnormalities that accompany these pathological changes. We previously identified abnormalities of multiple molecules associated with glutamatergic neurotransmission, including changes in NMDA receptor subunit transcripts and binding sites and NMDA receptor-associated post-synaptic density (PSD) protein transcripts in the thalamus of elderly patients with schizophrenia. In the present study, we performed western blot analysis to determine whether protein levels of NMDA receptor subunits (NR1, NR2A, NR2B) and associated PSD proteins (NF-L, PSD95, SAP102) are altered in schizophrenia. Thalamic tissue from each subject was grossly dissected into two regions: a dorsomedial region containing limbic-associated dorsomedial, anterior and central medial thalamic nuclei; and a ventral thalamus region that primarily consisted of the ventral lateral nucleus. We observed increased protein expression of the NR2B NMDA receptor subunit and its associated intracellular protein, PSD95, in the dorsomedial thalamus of patients with schizophrenia, but the other molecules were unchanged, and we found no changes in the ventral thalamus. These data provide additional evidence of thalamic neurochemical abnormalities, particularly in thalamic nuclei which project to limbic regions of the brain. Further, these findings provide additional evidence of NMDA receptor alterations in schizophrenia, which may play an important role in the neurobiology of the illness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65970/1/j.1471-4159.2006.03954.x.pd
The VIMOS Public Extragalactic Redshift Survey (VIPERS): from the galaxy clustering ratio measured at
We use a sample of about 22,000 galaxies at from the VIPERS
PDR-1 catalogue, to constrain the cosmological model through a measurement of
the galaxy {\it clustering ratio} . This statistic has favourable
properties, being defined as the ratio of two quantities characterizing the
smoothed density field in spheres of given radius : the value of its
correlation function on a multiple of this scale, , and its variance
. For sufficiently large values of , this is a universal
number, capturing 2-point clustering information independently of the linear
bias and linear redshift-space distortions of the specific galaxy tracers. In
this paper we discuss in detail how to extend the application of
to quasi-linear scales and how to control and remove observational selection
effects which are typical of redshift surveys as VIPERS. We verify the accuracy
and efficiency of these procedures using mock catalogues that match the survey
selection process. These results evidence the robustness of to
non-linearities and observational effects, which is related to its very
definition as a ratio of quantities that are similarly affected.
We measure . In addition to the great
precision achieved on our estimation of using VIPERS PDR-1, this
result is remarkable because it appears to be in good agreement with a recent
estimate , obtained applying the same technique to the SDSS-LRG
catalogue. It, therefore, suports the robustness of the present analysis.
Moreover, the combination of these two measurements at and provides us with a very precise estimate
which highlights the great consistency between our estimation and other
cosmological probes such as BAOs, CMB and Supernovae.Comment: 18 pages, 17 figures, accepted for publication in A&A, references
adde
Mechanically-Controlled Binary Conductance Switching of a Single-Molecule Junction
Molecular-scale components are expected to be central to nanoscale electronic
devices. While molecular-scale switching has been reported in atomic quantum
point contacts, single-molecule junctions provide the additional flexibility of
tuning the on/off conductance states through molecular design. Thus far,
switching in single-molecule junctions has been attributed to changes in the
conformation or charge state of the molecule. Here, we demonstrate reversible
binary switching in a single-molecule junction by mechanical control of the
metal-molecule contact geometry. We show that 4,4'-bipyridine-gold
single-molecule junctions can be reversibly switched between two conductance
states through repeated junction elongation and compression. Using
first-principles calculations, we attribute the different measured conductance
states to distinct contact geometries at the flexible but stable N-Au bond:
conductance is low when the N-Au bond is perpendicular to the conducting
pi-system, and high otherwise. This switching mechanism, inherent to the
pyridine-gold link, could form the basis of a new class of
mechanically-activated single-molecule switches
IGBT pretvarač za velike snage s mekim sklapanjem
A soft-switching topology for high power buck converter is proposed. Zero-current turn-on and zero-voltage turn-off is achieved without auxiliary switches. All active switches in the converter transmit power to the load equally. Converter control is simple despite four active switches. Converter operation is described and DC analysis is carried out. All operation modes are identified. The condition for soft-switching is derived. A full-scale 38 kW laboratory prototype with 1700 V IGBT modules is built for railway application. Switching frequency is fixed at 20 kHz. Experimental results are shown. The results confirm the analysis. A high efficiency of 97 % is achieved.Predstavljena je nova topologija silaznog istosmjernog pretvarača s mekim sklapanjem pogodna za velike snage. Isklapanje pri nuli napona i uklapanje pri nuli struje ostvareno je bez pomoćnih sklopki. Sve aktivne sklopke u pretvaraču prenose snagu u teret podjednako. Upravljanje pretvaračem je jednostavno unatoč većem broju aktivnih sklopki. Opisan je i analiziran rad pretvarača. Identificirani su svi načini rada. Izvedeni su uvjeti za meko sklapanje. Izra.en je laboratorijski model pretvarača u punoj snazi od 38 kW. Model je izveden s 1700 V-tnim IGBT modulima, a za primjenu na tračničkim vozilima. Sklopna frekvencija je konstantna i iznosi 20 kHz. Prikazani su rezultati mjerenja. Potvr.ena je provedena analiza. Postignut je visoki stupanj korisnog djelovanja od 97 %
- …