Proton-Capture Rates on Carbon Isotopes and Their Impact on the Astrophysical

The ^{12}C/^{13}C ratio is a significant indicator of nucleosynthesis and mixing processes during hydrogen burning in stars. Its value mainly depends on the relative rates of the ^{12}C(p,γ)^{13}N and ^{13}C(p,γ)^{14}N reactions. Both reactions have been studied at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Italy down to the lowest energies to date (E_{c.m.}=60 keV) reaching for the first time the high energy tail of hydrogen burning in the shell of giant stars. Our cross sections, obtained with both prompt γ-ray detection and activation measurements, are the most precise to date with overall systematic uncertainties of 7%-8%. Compared with most of the literature, our results are systematically lower, by 25% for the ^{12}C(p,γ)^{13}N reaction and by 30% for ^{13}C(p,γ)^{14}N. We provide the most precise value up to now of 3.6±0.4 in the 20-140 MK range for the lowest possible ^{12}C/^{13}C ratio that can be produced during H burning in giant stars.

Association of simian immunodeficiency virus Nef with cellular serine/threonine kinases is dispensable for the development of AIDS in rhesus macaques.

The nef gene of simian immunodeficiency virus (SIV) is essential for high viral load and induction of AIDS in rhesus monkeys. A mutant form of the SIVmac239 Nef, which contains changes in a putative SH3-binding domain (amino acids 104 and 107 have been changed from PxxP to AxxA), does not associate with cellular serine/threonine kinases, but is fully active in CD4 downregulation and associates with the cellular tyrosine kinase Src. Infection of two rhesus macaques with SIVmac239 containing the mutant AxxA-Nef caused AIDS and rapid death in both animals. No reversions were observed in the majority of nef sequences analyzed from different time points during infection and from lymphatic tissues at the time of death. Our findings indicate that the putative SH3-ligand domain in SIVmac Nef and the association with cellular serine/threonine kinases are not important for efficient replication and pathogenicity of SIVmac in rhesus macaques.

The investigation on the mechanism of electrochemical hydrogen storage in sandwich nickel foam/palladium/carbon nanofibers electrodes.

The kinetics of the process of reversible hydrogen sorption occurring in/on the nickel foam/palladium/carbon nanofibers (Ni/Pd/CNFs) electrodes is examined. It was shown that the hydrogen sorption/desorption properties for palladium can be altered after Pd layer is sandwiched between nickel foam and carbon nanofibers (CNF) layers. The layered Ni/Pd/CNFs electrodes were prepared by a two-step method consisting of chemical deposition of a very thin palladium layer on the Ni foam surface to form Ni/Pd electrodes followed by coating the Pd surface with the CNF layer by the CVD method. The process of hydrogen sorption/desorption into/from Ni/Pd as well as Ni/Pd/CNF electrodes was examined in alkaline electrolyte using the cyclic voltammetry method. The presence of CNF layer on the Pd surface exerts a great influence on the mechanism of the anodic desorption of hydrogen. A new anodic peak of hydrogen desorption revealed for Ni/Pd/CNF electrodes is ascribed to hydrogen storage in CNF phase. The CV measurements showed distinct differences between the rate of hydrogen release from the palladium and carbon phase.

A dileucine motif in HIV-1 Nef is essential for sorting into clathrin-coated pits and for downregulation of CD4.

Nef, a approximately 200 residue multifunctional regulatory protein of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), interacts with components of host cell signal transduction and clathrin-dependent protein sorting pathways. The downregulation of surface CD4 molecules and major histocompatibility complex (MHC) class I antigens by Nef is believed to be important in AIDS pathogenesis [1-7]. Nef contains a globular core domain and two disordered segments--a myristylated arm at the amino terminus and a carboxy-terminal loop projecting from the globular core [8,9]. Here, we aimed to determine the sorting signals in HIV-1 Nef that were responsible for its involvement in the clathrin-mediated pathway. We found that a sequence in the carboxy-terminal disordered loop of Nef is essential for downregulation of CD4. This sequence resembles the dileucine motif, one of two well-characterized sorting signals that target membrane proteins to clathrin-coated vesicles. The dileucine-motif-containing segment of Nef bound directly and specifically to the beta-adaptin subunit of the clathrin adaptor complexes AP-1 and AP-2, which are responsible for recruiting sorted proteins into coated pits. Unlike wild-type Nef, a mutant form of Nef that lacked the dileucine motif did not localize to clathrin-coated pits and did not downregulate CD4 expression, although it could downregulate MHC class I surface expression. Thus, the dileucine motif in HIV-1 is required for CD4 downregulation and for interaction with clathrin adaptor complexes.

Unit-length line-1 transcripts in human teratocarcinoma cells.

We have characterized the approximately 6.5-kilobase cytoplasmic poly(A)+ Line-1 (L1) RNA present in a human teratocarcinoma cell line, NTera2D1, by primer extension and by analysis of cloned cDNAs. The bulk of the RNA begins (5' end) at the residue previously identified as the 5' terminus of the longest known primate genomic L1 elements, presumed to represent "unit" length. Several of the cDNA clones are close to 6 kilobase pairs, that is, close to full length. The partial sequences of 18 cDNA clones and full sequence of one (5,975 base pairs) indicate that many different genomic L1 elements contribute transcripts to the 6.5-kilobase cytoplasmic poly(A)+ RNA in NTera2D1 cells because no 2 of the 19 cDNAs analyzed had identical sequences. The transcribed elements appear to represent a subset of the total genomic L1s, a subset that has a characteristic consensus sequence in the 3' noncoding region and a high degree of sequence conservation throughout. Two open reading frames (ORFs) of 1,122 (ORF1) and 3,852 (ORF2) bases, flanked by about 800 and 200 bases of sequence at the 5' and 3' ends, respectively, can be identified in the cDNAs. Both ORFs are in the same frame, and they are separated by 33 bases bracketed by two conserved in-frame stop codons. ORF 2 is interrupted by at least one randomly positioned stop codon in the majority of the cDNAs. The data support proposals suggesting that the human L1 family includes one or more functional genes as well as an extraordinarily large number of pseudogenes whose ORFs are broken by stop codons. The cDNA structures suggest that both genes and pseudogenes are transcribed. At least one of the cDNAs (cD11), which was sequenced in its entirety, could, in principle, represent an mRNA for production of the ORF1 polypeptide. The similarity of mammalian L1s to several recently described invertebrate movable elements defines a new widely distributed class of elements which we term class II retrotransposons.

Two modes of aggregation of artificial H1-DNA complexes depending on the rate of decrease of ionic strength.

The properties of H1-DNA artificial complexes, formed at different rates of decrease of NaCl concentration from 0.9 to 0.15 M, were investigated. It was found that two distinct processes, both depending on the rate of the concentration decrease, lead to the formation of aggregates differing in: the ability to form sediments, the distribution of sedimentation constants, the initial turbidity and its changes during trypsin and DNAase I digestion, and the H1/DNA ratio in the sediments. The accessibility of DNA in the complexes to DNAase I and the properties of nonaccessible DNA fragments led us to the conclusion that, at the H1/DNA ratio equal 0.2, the H1 molecules are clustered along the DNA chain independently of the rate of complex formation.

Bovine 1.709 satellite. Recombination hotspots and dispersed repeated sequences.

The nucleotide sequence of 3800 base-pair repeated unit of bovine 1.709 satellite was determined. The 3800 base-pair unit is not internally repeated and contains members of at least three different families of elements that are dispersed in the bovine genome. Two of three elements are associated with extensive length polymorphism within the satellite repeat unit. One of these comprises the 3' end of the bovine Alu-like sequences; the second is composed of C-A dinucleotides.

Construction of primary and subtracted cDNA libraries from early embryos.

By modifying current cDNA cloning and electroporation methods, large and representative murine cDNA libraries were synthesized from 10 to 100 ng mRNA isolated from unfertilized egg and preimplantation mouse embryos. High cloning efficiency is essential for complete representation of genes expressed in egg and preimplantation embryos and for the isolation of stage-specific genes using subtractive hybridization. Because the mouse embryo contains no more than 50 pg of poly(A)+ mRNA at any stage of preimplantation development, approximately 5000-10,000 embryos are required to obtain enough mRNA to synthesize libraries using current methods. To obtain a representative library that also includes rare transcripts, the size of the library should be at least 10(6) clones. The average percent conversion of mRNA to single-stranded cDNA was 20-40%, so that a cloning efficiency of nearly 2 x 10(8) cfu/microgram cDNA is required for such a cDNA library. No previous methods have provided directional cloning of cDNA into plasmids with these high efficiencies. The advent of electroporation methods for the introduction of nucleic acids into bacteria has made possible the use of standard plasmid vectors for high-efficiency cDNA cloning. Plasmid vectors are currently available that can accommodate the directional cloning of cDNA such that T7 and T3 RNA polymerase promoter sequences can be used to generate sense and anti-sense transcripts for subtractive hybridization and riboprobe synthesis. The cDNA libraries we derived using this methodology are a reusable and abundant source of genetic information about the control of preimplantation development. Specialized subtractive cDNA libraries enriched for genes expressed exclusively at a predetermined time in development give access to genes expressed in a stage-specific manner. The ability to construct new cDNA libraries from limited amounts of starting material ensures the provision of new and important resources for the identification and study of novel genes or gene families, and it is an important new tool for understanding the molecular control of mammalian development.

Hybridization of restriction fragments derived from calf satellite I DNA.

Two DNA fragments, the 643 base pairs (bp) and 621 bp long, obtained by endoR.Pst nuclease digestion of the 1350 bp basic repetitive unit of the calf satellite I DNA and cloning, do not hybridize with each other. Both of them, however, hybridize with the 970 and 1550 bp fragments, the sequence of which has been found to be homologous with that of the satellite I DNA.

Interleukin-6, soluble interleukin-2 receptor and soluble interleukin-6 receptor in the sera of patients with different histological patterns of rheumatoid synovitis.

OBJECTIVE: The present study was conducted to investigate whether the serum levels of interleukin 6 (IL-6), soluble IL-2 receptor (sIL-2R) and sIL-6R are associated with the morphological appearance of rheumatoid arthritis (RA). METHODS: Using the ELISA technique we measured the IL-6, sIL-2R and sIL-6R concentrations in the serum of 34 patients with RA and 28 patients with osteoarthritis (OA). Histological analysis of synovial samples distinguished 2 types of rheumatoid synovitis. Twenty-one RA specimens presented diffuse infiltrates of mononuclear cells without any specific microanatomical organization. In remaining 13 samples the formation of lymphocytic follicles with germinal center-like structures was found. RESULTS: Serum levels of IL-6, sIL-2R and sIL-6R were elevated in patients with RA compared to the OA control group (p < 0.001, p < 0.001 and p < 0.05 respectively). Concentrations of IL-6 and sIL-2R were highest in the serum of RA patients with follicular synovitis in comparison to patients with diffuse synovitis (p < 0.001 and p < 0.01 respectively) and could distinguish RA patients with these two histological variants of the disease. Serum levels of IL-6 and sIL-2R correlated with markers of disease activity such as ESR and CRP levels. In addition, the clinical data suggest a more severe disease among RA patients with follicular synovitis. CONCLUSION: Distinct histological types of rheumatoid synovitis associated with unique serum concentrations of IL-6 and sIL-2R reflect levels of disease activity and confirm the concept of RA heterogeneity.

Trait memory and behavior memory: the effects of alternative pathways on impression judgment response times.

Carlston (1980a) and Lingle (1983) argued that remembered behaviors, previous trait inferences, or both may be accessed and used in making new trait inferences, depending on a variety of factors. In this article we relate this argument to a spreading activation model of memory and suggest factors that should affect the relative accessibility of inferences and behaviors during trait judgment processes. In our study we varied several of these factors and assessed accessibility, using response-time methods. The results of this study strongly support the model's prediction that prompting inference formation facilitates subsequent trait judgment response times, but only when relevant behavior memories have not been recently primed. We theorize that the inference manipulations used in this study strengthened the direct pathway to a relevant trait concept, but that the strength of this pathway was immaterial to judgment response times when a "proximal prime" directed retrieval efforts along an alternative "behavioral" route to the trait information. The results also suggest that the proximal behavior prime facilitated trait responses among subjects who had not been induced to make trait inferences, but slowed trait responses among subjects who had previously been induced to make trait inferences.

Savings in relearning: II. On the formation of behavior-based trait associations and inferences.

Five experiments based on Carlston and Skowronski's (1994) relearning paradigm suggest that people spontaneously derive trait knowledge about actors from behaviors but that this knowledge may reflect either explicit trait inference processes or implicit actor-trait associations. Experiments 1 and 2 found that inference-instructed and control Ss showed equivalent savings in subsequent efforts to learn actor-trait pairs but not when instructed Ss initially inferred the wrong trait. Experiment 3 showed that savings were equivalent for stimuli from different sources, and Experiment 4 showed that savings effects persisted even when the target was only incidentally associated with a stimulus behavior. Finally, Experiment 5 suggests that after several days, even explicit trait inferences can become inaccessible to intentional retrieval, although the earlier experiments show that they continue to exert an implicit effect on learning.

Spontaneous trait transference to familiar communicators: is a little knowledge a dangerous thing?

In most social cognition research participants are presented with unattributed information about unfamiliar stimulus persons. However, in the real world it is more common for people to learn about others through social communication and to know something about those with whom they communicate. Such issues are explored in relation to spontaneous trait transference, a phenomenon in which communicators are perceived as having traits that they merely describe in others. Three studies show that even familiar communicators became associated with, and attributed, the traits implied by their remarks. Surprisingly, these effects occurred even when the implied traits were incongruent with participants' prior knowledge about these communicators. The results are discussed in terms of (a) the generalizability of social cognition research, (b) the automaticity of simple associative phenomena, and (c) the interplay of simple associative and higher level processes.

Spontaneous trait transference: communicators taken on the qualities they describe in others.

Spontaneous trait transference occurs when communicators are perceived as possessing the very traits they describe in others. Study 1 confirmed that communicators become associated with the trait implications of their descriptions of others and that such associations persist over time. Study 2 demonstrated that these associations influence specific trait impressions of communicators. Study 3 suggested that spontaneous trait transference reflects simple associative processes that occur even when there are no logical bases for making inferences. Finally, Study 4 used more naturalistic stimuli and provided additional evidence that the phenomenon reflects mindless associations rather than logical attributions. Together these studies demonstrate that spontaneous trait transference is a reliable phenomenon that plays a previously unrecognized role in social perception and interaction.

Direct muscular neurotization as a method of treatment of irreparable nerve injuries.

Authors have presented of 12 patients with irreparable nerve injuries treated by direct motor nerve implantation into muscle belly (direct muscular neurotization). Results were evaluated in Sunderland scale. Motor function of the neurotized muscles following 12 months from operation was in range of between M3 and M4.

The results of laminectomy and laminoplasty in cervical myeloradiculopathy.

The authors present the results of laminectomy and laminoplasty in 20 patients with cervical myeloradiculopathy according to the JOA score. Improvement was noted in 74% of the patients after laminoplasty and in 70% of the patients after laminectomy. On the whole decompression is a good method of treatment in this kind of disease.

[Electroneurographic and electromyographic assessment of rat skeletal muscle reinnervation after microsurgical implantation of nerve into muscle venter]. / Elektroneurograficzna i elektromiograficzna ocena reinerwacji miesni szkieletowych szczura po mikrochirurgicznej implantacji nerwu w brzusiec miesnia.

The purpose of the study was an assessment of the reinnervation of paralysed rat muscles after implantation of nerve into muscle venter (neurotization). The study was carried out in three groups of rats, with neurotization performed in two groups, the third group served as control. Reinnervation was assessed by means of electroneurography (eng) and electromyography (emg) during electrostimulation of the implanted nerve. Latency and amplitude of M response were evaluated quantitatively. The study demonstrated that functional reinnervation of muscle after nerve implantation into its venter was possible, and the process of reinnervation developed at the highest rate within 16 weeks after neurotization. The use of nerve graft bridging the distance between the stump of the severed nerve and the denervated muscle had no unfavourable effect on the end-result of neurotization.

[Peripheral nerve regeneration by autografts in rats. II. Electrophysiological assessment]. / Regeneracja nerwów obwodowych szczura po rekonstrukcji ubytku wlasnopochodnym przeszczepem miesnia. II. Ocena elektrofizjologiczna.

Peripheral nerves repairing using freeze-thawed skeletal muscle autografts were compared to conventional nerve grafts with respect to their electrical properties. It was found that the amplitude and distal latency of action potentials in both groups were not significantly different 3 and 6 months after the operation. These observations support the thesis that peripheral nerve repair by freeze-thawed autogenous muscle grafts may have a significant role in the reconstruction of injured nerves.

[Regeneration of peripheral nerves by muscle autografts in rats. I. Morphological and morphometrical evaluation]. / Regeneracja nerwów obwodowych szczura po rekonstrukcji ubytku wlasnopochodnym przeszczepem miesnia. I. Ocena morfologiczna i morfometryczna.

Regeneration of myelinated axons with 1 cm freeze-thawed skeletal muscle autografts was compared with nerve grafts in the rats. Regeneration was assessed histologically and morphometrically in the grafts and distal nerve stumps. Recovery of axon numbers and fibre diameters in distal nerve stumps was similar in the two kinds of grafts 6 months after operation. These observations suggest that freeze-thawed autogenous muscle grafts might be used in the repair of peripheral nerves.