Electrodeposition of Cu from acidic sulphate solutions containing cetyltrimethylammonium bromide (CTAB)

In this paper we report a study of the electrodeposition of Cu from an acidic sulphate solution containing cetyltrimethylammonium bromide (CTAB). This investigation is based on cyclic voltammetry, in situ surface-enhanced Raman spectroscopy (SERS), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Adsorption of CTAB over a wide range of cathodic potentials was proved spectroelectrochemically, encompassing both conditions where compact and loose Cu grows (up to −0.4 and between −0.4 and −1 V vs. Ag/AgCl, respectively). Furthermore, we found that CTAB tends to react cathodically, undergoing the loss of the aliphatic tail at lower cathodic potentials and the formation of an allylic product at higher polarisations. CTAB deeply impacts the Cu growth mode: ordered ridges of compact Cu crystallites form at low cathodic potentials—where the electrodeposition process is strongly inhibited by CTAB adsorption—and nanoparticles grow under hydrogen-evolution conditions.     

Scanning gate imaging of quantum point contacts and the origin of the 0.7 anomaly

The origin of the anomalous transport feature appearing at a conductance G ≈ 0.7 × (2e²/h) in quasi-1D ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been proposed to explain it, but a general consensus has not been achieved. Proposed explanations have been based on quantum interference, the Kondo effect, Wigner crystallization, and other phenomena. A key open issue is whether the point defects that can occur in these low-dimensional devices are the physical cause behind this conductance anomaly. Here we adopt a scanning gate microscopy technique to map individual impurity positions in several quasi-1D constrictions and correlate these with conductance characteristics. Our data demonstrate that the 0.7 anomaly can be observed irrespective of the presence of localized defects, and we conclude that the 0.7 anomaly is a fundamental property of low-dimensional systems.

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Contribution of enterococci to the spread of antibiotic resistance in the production chain of swine meat commodities

Thirty-six samples, including fecal specimens, dry feedstuffs, raw and processed pork meat products, and dry fermented sausages, were collected from two production chains of swine meat commodities and analyzed for the presence of 11 antibiotic resistance (AR) genes. Specific PCR assays carried out on DNA extracted directly from the samples revealed a high incidence of the genes tet(K) (80.5%), ermB (66.7%), and tet(M) (66.7%). Feces and feedstuffs gave the largest number of positive amplifications. To elucidate the contribution of enterococci to the occurrence and spread of AR, 146 resistant enterococci were isolated, and their identity, genetic fingerprints, and AR gene profiles were determined by means of molecular techniques. Enterococcus faecalis and Enterococcus faecium were the predominant isolated species (43.8 and 38.4%, respectively); Other Enterococcus species identified were E. durans (8.9%), E. hirae (2.7%), E. gallinarum (2.1%), E. mundtii (2.1%), and E. casseliflavus (2.1%). A number of isolates displayed a complex AR gene profile comprising up to four different resistance determinants. The genes tet(M) and ermB were highly diffused, being present in 86.9 and 84.9%, respectively, of the isolates. The application of amplified fragment length polymorphism fingerprinting was particularly valuable to monitor the resistant enterococcal isolates along the production chain and to individuate steps in which contamination might occur. In fact, isolates of E. faecalis and E. faecium showing the same amplified fragment length polymorphism profile and AR gene pattern were detected in samples taken at different steps of the food chain suggesting three cases of bacterial clonal spread.     

Liquid chromatographic-mass spectrometric analysis of conjugated diene fatty acids in a partially hydrogenated fat

A commercially available partially hydrogenated fat was analyzed for fatty acids containing conjugated dienes. The fatty acids were isolated by high-performance liquid chromatography (HPLC), and analyzed with a photodiode array detector and an atmospheric-pressure ionization mass spectrometer. Conventional and second-derivative ultraviolet (UV) spectra of the peaks eluting from the HPLC were recorded with the photodiode array detector, and peaks displaying second-derivative UV spectra characteristic of the conjugated diene chromophore were analyzed by mass spectrometry. The UV and mass spectra of the fatty acids with conjugated dienes, present in the partially hydrogenated fat, were identical to those of reference preparations of linoleic acid isomers with conjugated dienes. The results obtained emphasize that care must be exercised in the interpretation of clinical and experimental data concerning the detection of conjugated dienes in tissues or body fluids of humans and experimental animals. The conjugated dienes may not reflect an ongoing process of lipid peroxidation, but may be of dietary origin.     

Associative priming in word fragment completion: a dissociation between explicit and implicit retrieval processes

Three experiments investigated associative priming in word fragment completion. In associative priming, the study word that acts as a prime is semantically related in some way to the response word that the subject must produce or respond to at test. For example, a prime might be semantically related to the solution to its paired word fragment (e.g. study "VANILLA", solve fragment "-H-C--A-E" at test, solution is "CHOCOLATE"). Associative priming therefore differs from both repetition and conceptual priming, in which the studied primes are themselves the words that must be produced or responded to at test. In Experiment 1, associative primes were found to influence word fragment completion performance on an explicit test, but not on an implicit test. Experiment 2 demonstrated that the effects of associative primes on explicitly instructed fragment completion cannot be attributed to the specific information about cue-prime relationships that is included in the explicit instructions. Experiment 3 demonstrated that a manipulation of modality, a variable known to disrupt implicit retrieval processes, disrupts repetition priming on an explicit test, but not associative priming. The results of these three experiments suggest that whereas repetition primes are retrieved from memory by both explicit and implicit retrieval processes, associative primes are retrieved by only explicit processes. These data suggest that implicit retrieval processes are cue-dependent processes which automatically retrieve memory information that provides a good match to retrieval cues. Explicit retrieval processes are cue-independent, functioning as an intentional retrieval set to access particular categories or types of memory information.     

Structure-activity relationships of the Kvbeta1 inactivation domain and its putative receptor probed using peptide analogs of voltage-gated potassium channel alpha- and beta-subunits

Certain beta-subunits exert profound effects on the kinetics of voltage-gated (Kv) potassium channel inactivation through an interaction between the amino-terminal "inactivation domain" of the beta-subunit and a "receptor" located at or near the cytoplasmic mouth of the channel pore. Here we used a bacterial random peptide library to examine the structural requirements for this interaction. To identify peptides that bind Kv1.1 we screened the library against a synthetic peptide corresponding to the predicted S4-S5 cytoplasmic loop of the Kv1.1 alpha-subunit (residues 313-328). Among the highest affinity interactors were peptides with significant homology to the amino terminus of Kvbeta1. We performed a second screen using a peptide from the amino terminus of Kvbeta1 (residues 2-31) as "bait" and identified peptide sequences with significant homology to the S4-S5 loop of Kv1.1. A series of synthetic peptides containing mutations of the wild-type Kvbeta1 and Kv1.1 sequences were examined for their ability to inhibit Kvbeta1/Kv1.1 binding. Amino acids Arg20 and Leu21 in Kvbeta1 and residues Arg324 and Leu328 in Kv1.1 were found to be important for the interaction. Taken together, these data provide support for the contention that the S4-S5 loop of the Kv1.1 alpha subunit is the likely acceptor for the Kvbeta1 inactivation domain and provide information about residues that may underlie the protein-protein interactions responsible for beta-subunit mediated Kv channel inactivation.     

Association between interleukin-4-producing T lymphocyte frequencies and reduced risk of graft-versus-host disease

BACKGROUND: We have previously developed and used limiting dilution analysis to measure frequencies of alloreactive cytotoxic T cell precursors (CTLp) and interleukin (IL)-2-producing T helper cells (IL-2/HTLp) to assess the risk of graft-versus-host disease in bone marrow transplantation (BMT). However, no test has been available to measure precursor frequencies of the important IL-4-secreting subset. METHODS: We have now established a limiting dilution analysis to measure the frequency of IL-4-producing T helper cells (IL-4/HTLp) using the IL-4-responsive indicator cell line CT.h4S and have applied this assay to measure alloreactive IL-4/HTLp frequencies in BMT donor-recipient pairs. These frequencies were then analyzed in the context of clinical data to assess the relationship between the number of donor anti-recipient IL-4-secreting T cells and disease outcome. RESULTS: Frequencies of IL-4/HTLp have been studied in HLA-identical siblings, HLA-"matched" unrelated, and HLA-mismatched combinations and found to range from approximately 1/500,000 in HLA-identical sibling pairs to -1/2,000 in HLA-DR-mismatched pairs. These frequencies were independent of those for IL-2/HTLp and showed a negative correlation with those for CTLp. Clinical follow-up of 30 patients showed that high IL-4/HTLp frequencies are associated with a reduced risk of severe graft-versus-host disease. High IL-4/HTLp frequencies may also indicate an increased risk of leukemia relapse. CONCLUSIONS: Our data suggest that measurement of IL-4/HTLp frequencies provides information distinct from that obtained with CTLp and IL-2/HTLp. This new assay provides a valuable additional method for optimizing donor selection in unrelated BMT.     

M<Emphasis Type="SmallCaps">osaic</Emphasis>: A Scalable Coherence Protocol

The coherence protocol presented in this work, denoted Mosaic, introduces a new approach to face the challenges of complex multilevel cache hierarchies in future many-core systems. The essential aspect of the proposal is to eliminate the condition of inclusiveness through the different levels of the memory hierarchy while maintaining the complexity of the protocol limited. Cost reduction decisions taken to reduce this complexity may introduce artificial inefficiencies in the on-chip cache hierarchy, especially when the number of cores and private cache size is large. Our approach trades area and complexity for on-chip bandwidth, employing an integrated broadcast mechanism in a directory structure. In energy terms, the protocol scales like a conventional directory coherence protocol, but relaxes the shared information inclusiveness. This allows the performance implications of directory size and associativity reduction to be overcome. As it is even simpler than a conventional directory, the results of our evaluation show that the approach is quite insensitive, in terms of performance and energy expenditure, to the size and associativity of the directory.