Oligosaccharide chains on the surface of human erythrocytes were labeled with the probe eosin 5-thiosemicarbazide. The probe was conjugated to aldehydes produced by oxidation of sialic acid and ...galactose residues. The probe is associated mostly with glycophorin A after sialic acid labeling, whereas multiple components, including band 3 and lipids, are labeled after galactose oxidation. Fast molecular motion was studied by measuring steady-state and picosecond time-resolved fluorescence depolarization. Slower motions were investigated by observing flash-induced transient dichroism. It was found that both eosin-labeled sialic acid and galactose residues exhibit a rapid motion with correlation time of approximately 3 nsec. This motion is assigned to independent motion of the probe, possibly in conjunction with a short segment of the oligosaccharide chain. The order parameter of the fast motion is 0.8-0.9, demonstrating that its angular amplitude is highly restricted. For eosin-labeled sialic acid, the order parameter in the microsecond time range is 0.2-0.3. It is deduced that a second, slower rotational motion is present, which is assigned to a cooperative motion of the oligosaccharide chains. The correlation time of this motion is in the range 10-7-10-5 sec. Some eosin-labeled galactose residues may have a similar slow motion, but most appear to be remarkably immobile over the time range 10-8-10-3 sec.
The role of mass media in community response to disaster forewarning is examined. Focus is on the effects of earthquake prediction on information exchange at the community level. Four steps of the ...information process are delineated: reception of warning; increase in interest; awakening of concern; & seeking of expert information after review of warning. Data were gathered from a survey of 1,700 Los Angeles County residents, from interviews of scientific & emergency preparedness personnel (N not given), & from the monitoring of 6 major Los Angeles newpapers from 1976 to 1979 for coverage of earthquake items. Variety in presentation & clarification of ambiguity are seen to affect people's receptivity to media coverage regarding earthquakes. How people evaluate a media reported earthquake threat & what experts -- if any -- are consulted are analyzed. Ways in which the media can hinder information seeking from experts are examined. 1 Figure. P. Lore.
Quantum computers promise to solve certain problems exponentially faster than possible classically but are challenging to build because of their increased susceptibility to errors. Remarkably, ...however, it is possible to detect and correct errors without destroying coherence by using quantum error correcting codes 1. The simplest of these are the three-qubit codes, which map a one-qubit state to an entangled three-qubit state and can correct any single phase-flip or bit-flip error of one of the three qubits, depending on the code used 2. Here we demonstrate both codes in a superconducting circuit by encoding a quantum state as previously shown 3,4, inducing errors on all three qubits with some probability, and decoding the error syndrome by reversing the encoding process. This syndrome is then used as the input to a three-qubit gate which corrects the primary qubit if it was flipped. As the code can recover from a single error on any qubit, the fidelity of this process should decrease only quadratically with error probability. We implement the correcting three-qubit gate, known as a conditional-conditional NOT (CCNot) or Toffoli gate, using an interaction with the third excited state of a single qubit, in 63 ns. We find 85\pm1% fidelity to the expected classical action of this gate and 78\pm1% fidelity to the ideal quantum process matrix. Using it, we perform a single pass of both quantum bit- and phase-flip error correction with 76\pm0.5% process fidelity and demonstrate the predicted first-order insensitivity to errors. Concatenating these two codes and performing them on a nine-qubit device would correct arbitrary single-qubit errors. When combined with recent advances in superconducting qubit coherence times 5,6, this may lead to scalable quantum technology.
Diaprepes abbreviatus (L.) is an insect pest of the US agriculture that originated from the Caribbean islands. Larvae are of economic importance in both nursery and commercial citrus plantings due to ...root feeding. Eight polymorphic microsatellite markers were developed from a (CA)subscript n-enriched genomic library of Diaprepes root weevil. Three to eight alleles were observed for each locus during screening of 17 to 25 individuals. Observed and expected heterozygosities ranged from 0.182 to 0.864 and 0.587 to 0.835, respectively. These markers will be useful to characterize the genetic variability and track the migration patterns of populations of D. abbreviatus (L.).
The serine/threonine protein kinase NIMA of Aspergillus nidulans is required for entry into mitosis and may function in parallel to the universal mitotic inducer p34cdc2. Here, we report the ...isolation of complementary DNAs encoding Nek2 and Nek3, two novel human protein kinases structurally related to NIMA. Sequence comparisons revealed several unique features which may define a family of NIMA-related protein kinases. Nek2 was chosen for further study since it represents the closest known mammalian relative of NIMA. Chromosomal mapping of the nek2 gene identified two independent loci on chromosomes 1 and 14, and Northern blot analyses revealed the expression of two distinct mRNAs of approximately 2.4 and 4.7 kilobases in all human cell lines examined. In HeLa cells synchronized by both drug arrest and elutriation, a strikingly cell cycle-dependent pattern of Nek2 expression could be observed; Nek2 protein was almost undetectable during G1 but accumulated progressively throughout S, reaching maximal levels in late G2. These observations demonstrate that Nek2 resembles Aspergillus NIMA, not only in its catalytic domain, but also in its cell cycle-dependent expression. Hence, the human Nek2 protein kinase may also function at the onset of mitosis.
The nimA gene encodes a protein-serine/threonine kinase that is required along with the p34cdc2 kinase for mitosis in Aspergillus nidulans. We have searched for human protein kinases that are related ...to the NIMA protein kinase using the polymerase chain reaction. Different pairs of degenerate oligonucleotides specific for conserved amino acid motifs in the catalytic domain of NIMA were used as primers in the polymerase chain reaction to amplify partial complementary DNAs (cDNAs) of protein kinases expressed in the promyelocytic leukemia cell line HL-60. Forty-one distinct cDNAs representing a broad spectrum of serine/threonine- and tyrosine-specific protein kinases were identified, and the sequences for 21 of these protein kinases were found to be unique. Three of these cDNAs represent a family of protein kinases whose members are related to NIMA and the murine nimA-related protein kinase Nek1. We discuss the success of this polymerase chain reaction approach with respect to the use of multiple primer pairs, the influence of primer degeneracy, and the tolerance of cDNA amplification to mismatches between primers and template mRNA.
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