In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, several two-layer technological quadrupole models of TQC ...series with 90 mm aperture and collar-based mechanical structure have been developed at Fermilab in collaboration with LBNL. This paper summarizes the results of fabrication and test of TQC02a, the second TQC model based on RRP Nb3Sn strand, and TQC02b, built with both MJR and RRP strand. The test results presented include magnet strain and quench performance during training, as well as quench studies of current ramp rate and temperature dependence from 1.9 K to 4.5 K.
Penetration of fullerene C
60
in hydrated molecular-colloidal form (FMC) and various C
60
water-soluble derivatives (FDs) through membranes of human erythrocytes, platelets and symbiosomes ...(subcellular organelles of plant origin) were tested. The FDs bearing amino acids induced pronounced depolarization of symbiosome membranes energized with Mg-ATP. In erythrocytes and platelets incubated in K
+
-free medium in the presence of FCCP, FDs with malonic acid pendants promoted acidification of the intracellular medium thereby simulating an effect of the K
+
ionophore valinomycin. Dissipation of ΔpH artificially induced on the plasma membrane of these cells was observed in the presence of C
60
-γ-aminobutiric acid which, in addition, strongly stimulated Mg-ATP-dependent generation of membrane potential on symbiosome membranes. C
60
-Arg was shown to dissipate K
+
-diffusion potential on erythrocyte membranes induced by valinomycin. Fullerene C
60
used in hydrated molecular-colloidal form (FMC) also entered symbiosomes and platelets as evidenced by the quenching of the fluorescence of the Ca
2+
indicator chlorotetracycline localized in the interior of these cells. These findings provide evidence for ease of permeation of these fullerene-based compounds through biological membranes from different type cells.
Anomalous increase of T C in UGa2 under pressure Kolomiets, Alexandre; Havela, Ladislav; Prchal, Jiří ...
Journal of the Korean Physical Society,
5/2013, Letnik:
62, Številka:
10
Journal Article
We compared mitochondrial DNA (mtDNA) restriction fragment profiles from samples of 13 bird species that occur on both sides of Beringia. All but two species, Lapland Longspur (Calcarius lapponicus) ...and Green-winged Teal (Anas crecca), exhibited evidence of genetic differentiation, albeit at varying degrees. Several species exhibited mtDNA differentiation consistent with species-level distinctness: Marbled Murrelet (Brachyramphus marmoratus), Three-toed Woodpecker (Picoides tridactylus), Whimbrel (Numenius phaeopus), Mew Gull (Larus canus), Black-billed Magpie (Pica pica), American Pipit (Anthus rubescens), and Rosy Finch (Leucosticte arctoa). Other species exhibited levels of mtDNA differentiation intermediate between populations and species: Barn Swallow (Hirundo rustica), Common Tern (Sterna hirundo), Common Snipe (Gallinago gallinago), and Pelagic Cormorant (Phalacrocorax pelagicus). Because of small sample sizes, we do not recommend formal taxonomic changes, although our data could be combined with other data to raise several taxa to species level. Our data do not indicate a consistent level of mtDNA differentiation between putatively conspecific populations on different sides of Beringia, suggesting different times of colonization or cessation of gene exchange. Most comparisons of birds within continents exhibit less mtDNA differentiation than our trans-Beringia comparisons, suggesting limited gene flow between continents.
High pressure resistivity of UPd3 Prchal, Jiří; Havela, Ladislav; Andreev, Alexander V.
High pressure research,
20/6/1/, Letnik:
32, Številka:
2
Journal Article
Recenzirano
Electrical resistivity of UPd
3
, the only known binary U-based intermetallic with localized 5f states, was studied under high pressures up to 10 GPa, testing a possible incipient delocalization due ...to the lattice compression. The data obtained revealed no tendency to any delocalization. The shoulder related to crystal-electric field effects between 10 and 15 K remains visible, being only shifted slightly towards higher temperatures with the increase in pressure.
A novel family of antifungal peptides was discovered in the wheat
T
riticum kiharae
Dorof. et Migusch. Two members of the family, designated Tk‐
AMP
‐
X
1 and
T
k‐
AMP
‐X2, were completely sequenced ...and shown to belong to the α‐hairpinin structural family of plant peptides with a characteristic C1XXXC2‐X(n)‐C3XXXC4 motif. The peptides inhibit the spore germination of several fungal pathogens
in vitro
. c
DNA
and gene cloning disclosed unique structure of genes encoding Tk‐
AMP
‐X peptides. They code for precursor proteins of unusual multimodular structure, consisting of a signal peptide, several α‐hairpinin (4‐Cys) peptide domains with a characteristic cysteine pattern separated by linkers and a C‐terminal prodomain. Three types of precursor proteins, with five, six or seven 4‐Cys peptide modules, were found in wheat. Among the predicted family members, several peptides previously isolated from
T. kiharae
seeds were identified. Genes encoding Tk‐
AMP
‐X precursors have no introns in the protein‐coding regions and are upregulated by fungal pathogens and abiotic stress, providing conclusive evidence for their role in stress response. A combined
PCR
‐based and bioinformatics approach was used to search for related genes in the plant kingdom. Homologous genes differing in the number of peptide modules were discovered in phylogenetically‐related
T
riticum
and
A
egilops
species, including polyploid wheat genome donors. Association of the Tk‐
AMP
‐
X
genes with
A
,
B
/
G
or
D
genomes of hexaploid wheat was demonstrated. Furthermore,
T
k‐
AMP
‐
X
‐related sequences were shown to be widespread in the Poaceae family among economically important crops, such as barley, rice and maize.
Database
Nucleotide sequence data have been deposited in the
EMBL
database under accession numbers:
HF562347
,
HF562348
,
HF562349
,
HF562350
,
HF562351
,
HF562352
,
HF562353
,
HF562354
,
HF562355
,
HF562356
,
HF562357
,
HF562358
,
HF562359
,
HF562360
,
HF562361
,
HF562362
,
HF562363
and
HF562364
.
Multiproxy datasets (geocryology, geochronology, sedimentology, palaeo-ecology) from permafrost exposures were used together with land surface information based on satellite imagery and thematic maps ...in order to reconstruct the Lateglacial to Holocene landscape and environmental dynamics of Bunge Land (Zemlya Bunge). This area of little relief, situated in the New Siberian Archipelago, connects the geomorphologically well-structured islands of Kotel'ny and Fadeevsky. A buried thermokarst landscape was found in the northwest region of the Bunge Land low terrace sand plain, whereas the Bunge Land high terrace seems to be an exposed residue of a similar late Quaternary thermokarst landscape. That is confirmed especially by radiocarbon accelerator mass spectrometry and optically stimulated luminescence age determinations, and by pollen analyses. Palaeogeographically, the late Pleistocene periglacial landscape and sedimentation of Bunge Land was closely connected to Kotel'ny and Fadeevsky; only later on seismotectonical block movements resulted in reshaping parts of Bunge Land. The Bunge Land low terrace area first subsided and the original landscape there was destroyed by marine inundation, followed by marine sedimentation. Subsequent block heave of the low terrace region exposed a vast sheet of marine sands which is continuously surficially reworked by aeolian processes, while the original alluvial plain landscape in the high terrace area was preserved and started degrading only by early Holocene thermokarst development. The studied exposures contain one of the northernmost (74.88°N) environmental records for the late Pleistocene–Holocene transition in the Eurasian Arctic.
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