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J E Moore

Publications and source records attributed to J E Moore.

At least 37 records · Page 2Linked to original sources
PubMed2005

Observation of spin Coulomb drag in a two-dimensional electron gas.

An electron propagating through a solid carries spin angular momentum in addition to its mass and charge. Of late there has been considerable interest in developing electronic devices based on the transport of spin that offer potential advantages in dissipation, size and speed over charge-based devices. However, these advantages bring with them additional complexity. Because each electron carries a single, fixed value (- e) of charge, the electrical current carried by a gas of electrons is simply proportional to its total momentum. A fundamental consequence is that the charge current is not affected by interactions that conserve total momentum, notably collisions among the electrons themselves. In contrast, the electron's spin along a given spatial direction can take on two values, +/- [planck]/2 (conventionally upward arrow, downward arrow), so that the spin current and momentum need not be proportional. Although the transport of spin polarization is not protected by momentum conservation, it has been widely assumed that, like the charge current, spin current is unaffected by electron-electron (e-e) interactions. Here we demonstrate experimentally not only that this assumption is invalid, but also that over a broad range of temperature and electron density, the flow of spin polarization in a two-dimensional gas of electrons is controlled by the rate of e-e collisions.

Journal Article↗
PubMed2005

Treatment and survival from colorectal cancer: the experience of patients at South Australian teaching hospitals between 1980 and 2002.

AIMS: To evaluate trends in colorectal cancer survival and treatment at South Australian teaching hospitals and degree of adherence to treatment guidelines which recommend adjuvant chemotherapy for Dukes' C colon cancers and combined chemotherapy and radiotherapy for high-risk rectal cancers. MATERIALS AND METHODS: Trends in disease specific survival and primary treatment were analysed, and comparisons drawn between diagnostic epochs, using cancer registry data from South Australian teaching hospitals. Statistical methods included univariate and multivariable disease specific survival analyses. RESULTS: Five-year survival increased from 48% in 1980-1986 to 56% in 1995-2002. Largest gains were for stage C, where survivals were higher when chemotherapy was part of the primary treatment. By comparison, gains in 1-year survival were largest for stage D. Chemotherapy was provided for 4% of patients with colorectal cancers in 1980-1986, increasing to 32% in 1995-2002. Among stage C cases below 70 years at diagnosis, the proportion having chemotherapy increased to 83% in 1995-2002. The most common chemotherapy was fluorouracil (5FU) as a single agent in 1980-1986 and 5FU with leucovorin in 1995-2002. As expected, radiotherapy was used more frequently for rectal than colon cancers, and particularly for stage C. Among stage C rectal cases below 70 years, the proportion having radiotherapy increased from 10% in 1980-1986 to 57% in 1995-2002. Approximately 93% of colorectal cancers were treated surgically. Patients not treated surgically tended to be aged 80 years or more and to present with distant metastases. CONCLUSIONS: Trends in chemotherapy and radiotherapy accord with evidence-based recommendations. There have been reassuring gains in survivals after adjusting for stage, grade and other prognostic indicators. The data show survival gains and treatment patterns that individual hospitals can use as benchmarks when evaluating their own experience.

Aged↗
PubMed2005

Frequency and distribution of group I intron genotypes of Candida albicans colonising critically ill patients.

A study is performed to examine the distribution and frequency of 25S rRNA intron genotypes of Candida albicans isolated from different anatomical sites of patients in an intensive care unit (ICU) setting. Germ-tube positive Candida isolates (n=65) from 65 patients are included and isolates are characterised by 25S intron genotyping, whereby all can be subdivided into four genotypes (A-D). Results demonstrated that there were no significant differences between the frequency and genotype distribution of the Candida isolates and the anatomical site of colonisation. Furthermore, analysis of the transposable intron region in the 25S rRNA gene demonstrated equal distribution, regardless of age and anatomical site of isolation (groin, throat, etc.). Therefore, there does not appear to be any selective pressure associated with any anatomical site, resulting in an ecological shift in the frequency of genotypes present. This suggests that C. albicans intron genotypes equally colonise those sites of the body examined in this study. Although such an ecological finding as this is interesting, it perpetuates the continued need to find a genotypic typing scheme that helps to identify the source (nosocomial or endogenous) and mode of entry of C. albicans into patients in the ICU setting, resulting in C. albicans bloodstream infection.

Adolescent↗
PubMed2005

Cystic fibrosis genotype and bacterial infection: a possible connection.

Patients with cystic fibrosis (CF) have repeated bacterial infection of the airways, which can lead to chronic infection. There is evidence that disease severity is determined by the genetic mutations present. This study aims to establish if CF genotype is related to the frequency and types of airway bacterial infection. Adult patients attending the regional CF unit are followed for two years and assigned to one of three groups depending on whether they are chronically infected with Burkholderia cepacia complex (BCC) organisms, Pseudomonas aeruginosa, or neither of these organisms. Genotype analysis is performed on all patients to determine which of the cystic fibrosis transmembrane regulator (CFTR) gene mutations are present. The numbers and types of organism with the CFTR mutations isolated from sputum are identified. Data are available on 59 patients: 15 colonised with BCC, 24 colonised with P. aeruginosa, and 20 not colonised with either organism. Twenty patients were homozygous for deltaF508, 25 were heterozygous, and the deltaF508 mutation was not present in the remaining 14 patients. Patients homozygous or heterozygous for the deltaF508 mutation had an increased likelihood of colonisation with BCC or P. aeruginosa, an increased number of positive sputum cultures and a higher frequency of multiple infecting organisms. Cystic fibrosis mutational analysis identified seven patients who had the R117H mutation. These patients were less likely to be colonised with BCC or P. aeruginosa. In conclusion, patients homozygous or heterozygous for the deltaF508 deletion are more likely to suffer airway colonisation with BCC or P. aeruginosa, with increased numbers of positive sputum cultures and infecting organisms. Those with the R117H mutation are less likely to be colonised by Gram-negative organisms.

Adult↗
PubMed2005

Quantitative colorimetric measurement of residual antimicrobials in the urine of patients with suspected urinary tract infection.

A simple microtitre plate assay is used to detect antimicrobial activity in clinical urine specimens and its potential as a screening tool is assessed. The assay is based on a colorimetric substrate, p-nitrophenyl-beta-D-glucopyranoside, in combination with a Bacillus subtilis strain to detect antimicrobial residues. The assay identified antimicrobial activity in 31% of the 527 clinical urine samples tested. The majority of the samples (65%) came from the community, with the rest comprising hospital inpatients (19%) and out-patients (16%). The results demonstrated that there is an association between gender and the presence of inhibitory substances, as 40% of males and 27% of females tested positive. Just over two-fifths of hospital patients (46%) tested positive for inhibitory substances, compared to 26% of samples from community patients. Of the 306 samples that were culture-negative (<10(4) bacteria/mL), 42% were positive for inhibitory substances, compared with 17% among the remaining 221 samples. However, there was no evidence of an association between age and the presence of inhibitory substances. This study demonstrates that the bacteriostatic effect of the bacterial preservative boric acid is sufficient to upset the specificity of the assay. Furthermore, it has been suggested that antimicrobial activity can confuse the interpretation of culture results, as they have been found to play a major role in the occurrence of apparently sterile pyuria.

Adolescent↗
PubMed2005

Detection of Chlamydia pneumoniae in atherosclerotic tissue: a comparative study of PCR and immunocytochemistry.

The reported prevalence of Chlamydia pneumoniae in atherosclerotic tissue appears to depend on the detection system used. This introduces problems in determining the role of C. pneumoniae in atherosclerosis. This study analyses the sensitivity and performance of molecular diagnostic methods for the detection of C. pneumoniae and polymerase chain reaction (PCR) inhibitors in atheromatous tissue. Atherosclerotic tissue taken from 30 coronary endarterectomies, nine coronary arteries from explanted hearts, 16 carotid and two femoral endarterectomies are studied. Nested PCR (nPCR) assays targeting the PstI restriction fragment, the OmpA gene and the CRP operon of the chlamydial genome and immunocytochemistry (ICC) are used. Internal controls (IC) are constructed to co-amplify with the specific amplicons and identify the presence of inhibitor. The OmpA, PstI and CRP operon PCR assays had similar analytical sensitivities. However, the OmpA PCR was most affected by PCR inhibitors. Despite this, eight samples (14%) tested positive in the OmpA nPCR and no positives were found using the PstI or CRP operon nPCRs. Primary isolates of C. pneumoniae obtained from 12 patients with acute respiratory infection were positive in all three assays. Of the 48 specimens available for ICC, 33 (69%) were positive for chlamydial antigens. These included samples found positive by PCR. Dilution of samples to eliminate PCR inhibitors may have contributed to the discordant ICC and PCR results. The OmpA PCR, when used with an IC to identify samples with PCR inhibitors, is a reliable tool. However, the sensitivity of the ICC methods justifies their continued use.

Adult↗
PubMed2005

Microbial ecology of the cystic fibrosis lung: does microflora type influence microbial loading?

This study aims to examine the association between the numbers of culturable microbial species forming the microflora of the lung in patients with cystic fibrosis (CF) and microbial loading (i.e., type[s] versus numbers). Additionally, it examines qualitative combinations of the microflora present in a large adult CF centre (n=138) in order to ascertain ecological relationships between the taxa present. The culturable microflora of sputum from 34 adults patients with CF are enumerated using a spread plate technique on non-selective agar, and the microflora identified phenotypically employing the API 20NE scheme. Microbiological examination of the 34 adult patients demonstrated that their sputum contained between one and three taxa, with a mean cell density of 8.25 +/- 0.85 log colony-forming units (cfu)/g sputum and a range of 5.91-9.74 log cfu/g sputum. Most colonising patterns demonstrated only Gram-negative infection (22/34), followed by a mixed Gram-positive/Gram-negative infection pattern (10/34). Only 2/34 patients had a single Gram-positive infection. Most patients (53%) were colonised by only one organism, with 38% of patients colonised by two organisms, and the remainder (4%) colonised with three organisms. There was no statistical difference (P>0.05) between microbial cell density and the number of taxa present (i.e., the greater number of taxa present in sputum did not produce a higher cell density). However, there was a significantly higher cell density (log 0.59 cfu/g sputum) noted for those patients who had only Gram-negative infection, compared to those who had a mixed Gram-negative/Gram-positive infection pattern (P=0.02). Relatively little is known about the ecological interactions that exist between the microflora in the CF lung. Further work is required to explore these interactions in order to aid understanding of the succession and dominance of Gram-negatives in chronic chest infections. Ultimately, a greater understanding of such interactions may allow the opportunity to manipulate the ecology of the lung to control otherwise problematic pathogens

Adult↗
PubMed2005

Campylobacter jejuni.

This review describes characteristics of the family Campylobacteraceae and traits of Campylobacter jejuni. The review then focuses on the worldwide problem of C. jejuni antimicrobial resistance and mechanisms of pathogenesis and virulence. Unravelling these areas will help with the development of new therapeutic agents and ultimately decrease illness caused by this important human pathogen.

Anti-Bacterial Agents↗
PubMed2005

Follow up of patients with ocular scarring secondary to LOC syndrome treated by amniotic membrane transplantation.

AIMS: To document and discuss the long term outcome of a new ophthalmic treatment for laryngo-onycho-cutaneous (LOC) syndrome. METHODS: Two children were treated by excision of ocular granulation tissue and ocular surface rehabilitation with frozen amniotic membrane (AM). The clinical course of both patients was followed and documented at 2 years and 4 years following the surgery. RESULTS: Patient 1 demonstrated limited recurrence of granulation tissue at 10 months. After 36 months, re-growth of granulation and scar tissue required a further three subsequent operations to the right eye in an attempt to keep the optical axis clear. 4 years postoperatively, neither eye has a clear visual axis. In contrast similar surgery for the right eye of patient 2 has been highly successful, with only very limited non-progressive recurrence after 2 years of follow up. The operation to the left eye has been similarly effective although the follow up is only 6 months. CONCLUSIONS: Ocular surface rehabilitation with AM is the first partially effective treatment for the eye complications of LOC syndrome. The surprising benefit from AM may stem from the primary pathology of the condition. LOC syndrome is caused by a genetic defect resulting in an unusual N-terminal deletion of the alpha3a chain of the basement membrane protein laminin 5. One mechanism through which AM transplantation may act to reduce ocular scarring in this disease is to supplement the abnormal secreted laminin 5 with healthy transplanted laminin. Despite its initial efficacy one episode of AM treatment does not guarantee long term control of the scarring process and variations in AM graft efficacy may be related to other complicating factors such as limbal stem cell deficiency or severity of the initial scarring process.

Amnion↗
PubMed2004

Entanglement entropy of random quantum critical points in one dimension.

For quantum critical spin chains without disorder, it is known that the entanglement of a segment of N>>1 spins with the remainder is logarithmic in N with a prefactor fixed by the central charge of the associated conformal field theory. We show that for a class of strongly random quantum spin chains, the same logarithmic scaling holds for mean entanglement at criticality and defines a critical entropy equivalent to central charge in the pure case. This effective central charge is obtained for Heisenberg, XX, and quantum Ising chains using an analytic real-space renormalization-group approach believed to be asymptotically exact. For these random chains, the effective universal central charge is characteristic of a universality class and is consistent with a c-theorem.

Journal Article↗
PubMed2004

Occurrence of Campylobacter in retail foods in Ireland.

A surveillance study was carried out to determine the prevalence of Campylobacter in a range of retail foods purchased in three Irish cities over a 20-month period between March 2001 and October 2002. In total 2391 food samples were analysed during this period. Campylobacter was isolated from 444 raw chicken (49.9%), 33 turkey (37.5%) and 11 duck samples (45.8%). Lower isolation rates of 7/221 (3.2%), 10/197 (5.1%) and 31/262 (11.8%) were observed for raw beef, pork and lamb, respectively. One sample of pork paté from 120 samples analysed (0.8%) was Campylobacter-positive. A total of three shellfish samples (oysters) from 129 raw specimens examined (2.3%) were found to contain Campylobacter. Low prevalences of the organism (0.9%) were also isolated from fresh mushrooms. Of 62 raw bulk tank milk samples analysed, Campylobacter was recovered in a single sample (1.6%). Campylobacter was not detected in any of the comminuted pork puddings, prepared vegetables and salads, retail sandwiches or cheeses made from unpasteurised milk. In total, 543 Campylobacter were isolated from all of the food samples analysed, of which 453 (83.4%) were confirmed as Campylobacter jejuni and the remaining 90 (16.6%) as Campylobacter coli.

Agaricales↗
PubMed2004

Strong-weak coupling self-duality in the two-dimensional quantum phase transition of p + ip superconducting arrays.

The 2D quantum phase transition that occurs in a square lattice of Josephson-coupled p +/- ip superconductors is an example of how four-body interactions in d = 2 reproduce nonperturbative effects caused by two-body interactions in d = 1. The ordered phase has an unconventional "bond order" of the local T-breaking variable. This problem can be analyzed using an exact self-duality; this duality in classical notation is the 3D generalization of the Kramers-Wannier duality of the 2D Ising model, and there are similar exact dualities in dimensions d > or = 3. We discuss the excitation spectrum and experimental signatures of the ordered and disordered phases, and the relationship between our model and previously studied behavior of 2D boson models with four-boson interactions.

Journal Article↗
PubMed2004

Current trends in the molecular diagnosis of infective endocarditis.

The introduction of molecular methods into biomedical science, particularly nucleic acid amplification techniques including the polymerase chain reaction, has significantly improved the diagnosis of several diseases. Likewise, the adoption of such molecular techniques to aid in the detection and identification of causal organisms in patients with infective endocarditis (IE) has been particularly beneficial in cases of difficult, atypical or culture-negative IE. Several different molecular approaches have been suggested for the diagnosis of IE, including variations in the type of cardiological specimens examined, nucleic acid extraction, gene target and molecular platform, each presenting their own advantages and disadvantages. This review examines the molecular approach to the detection and identification of causal agents of IE and provides details and a discussion of the application of such methods, particularly those implemented over the last 7 years.

Bacteria↗