Real-time broad-range PCR versus blood culture. A prospective pilot study in pediatric cancer patients with fever and neutropenia

MATERIALS AND METHODS: In a pilot study, results of real-time broad-range (16S rRNA) polymerase chain reaction (PCR) performed on 45 blood samples of pediatric cancer patients with fever and neutropenia were compared with blood culture results. RESULTS: The PCR assay used, having proven a high sensitivity in artificially spiked blood samples, was positive in only three of ten blood culture-positive samples, and it was positive in 10 of 35 (29%) culture-negative samples. CONCLUSION: This broad-range PCR assay, which may identify not-grown bacteria potentially contributing to fever, needs improvement in sensitivity, and different reasons for positive PCR in negative blood culture samples need to be assessed before clinical application.

Mastoiditis in children: a prospective, observational study comparing clinical presentation, microbiology, computed tomography, surgical findings and histology

The aim of this study was to obtain comprehensive data on clinical presentation, microbiology, computed tomography, surgical findings and histology in acute, sub-acute and chronic mastoiditis. We performed a prospective, observational study in children under 16 years of age presenting to our institution during the 2-year period beginning in April 2000. The children were examined and their condition treated in accordance with a standardized protocol elaborated by the paediatric, otolaryngology (ORL) and radiology departments. Thirty-eight patients were hospitalized (22 with acute mastoiditis, seven with sub-acute mastoiditis, nine with chronic mastoiditis). There were 30 complications present in 21 patients (55%). Streptococcus pyogenes was the most common pathogen (7/24 cases), followed by Streptococcus pneumoniae (4/24 cases). Mastoid surgery was performed in 29 patients. Histology of mastoid tissue revealed predominantly acute inflammation in two cases, mixed acute/chronic inflammation in 19 cases and predominantly chronic inflammation in seven cases. Radiologic data were evaluated retrospectively. Spiral, volume-based high-resolution (HR) computed tomography (CT) of the temporal bone had a sensitivity of 100%, specificity of 38%, positive predictive value (PPV) of 50% and negative predictive value (NPV) of 100% in detecting coalescence of mastoid trabeculae. Cranial CT with contrast had a sensitivity of 80%, specificity of 94%, PPV of 80% and NPV of 94% in identifying intra-cranial extension. Conclusion: histological evidence suggests that sub-acute/chronic infection underlies not only sub-acute and chronic mastoiditis, but most cases of acute mastoiditis as well. HR-CT of the temporal bone is effective in ruling out coalescence. Cranial CT is valuable in identifying intra-cranial extension. Cranial and HR-CT are recommended in the examination of children with mastoiditis.

[Bisexuality and AIDS. Implications for heterosexual HIV infections in women]

One of the possible pathways into heterosexual population is the transfer of HIV-virus from bisexual men to their female partners. Therefore sexual behaviour of HIV-positive and -negative bisexual men (n = 31) before and after Aids-disease was analysed. Prior to the Aids-epidemic promiscuous behavior towards male partners (about one female partner per year versus 10 male partners per year). Relatively common contacts to woman occurred within steady relationships. After contact with HIV-test and personal counselling sexual practice became significantly different. The number of female and male contacts was markedly reduced, especially female chance acquaintances were avoided; safer sex was preferred and readiness to inform female partners about bisexuality was increased. This study suggests that reduction of risk for HIV-infection of female partners by homosexual men can be achieved by means of a HIV-test and personal counselling, a possibility that should be considered in preventive concepts.

One-year bacterial colonization patterns of Staphylococcus aureus and other bacteria at implants and adjacent teeth

AIMS: (i) To assess the pattern of early bacterial colonization on titanium oral implants after installation, at 12 weeks and at 12 months, (ii) to compare the microbiota at submucosal implant sites and adjacent subgingival tooth sites and (iii) to assess whether or not early colonization was predictive of 12-month colonization patterns. MATERIAL AND METHODS: Submucosal/subgingival plaque samples from 17 titanium oral implants and adjacent teeth were analyzed by checkerboard DNA-DNA hybridization 30 min, 12 weeks and 12 months after implant installation. RESULTS: At 12 months, none of the inserted implants had been lost or presented with signs of peri-implantitis. The distribution of sites at implants and teeth with bleeding on probing varied between 2% and 11%. Probing pocket depths < or =3 mm were found at 75% of implant sites. At 12 months, the sum of the bacterial counts of 40 species was statistically significantly higher at tooth compared with implant sites (mean difference: 34.4 x 10(5), 95% confidence interval -0.4 to 69.4, P<0.05). At 12 months, higher individual bacterial counts at tooth sites were found for 7/40 species compared with implant sites. Detection or lack of detection of Staphylococcus aureus at implant sites at 12 weeks resulted in the highest positive (e.g. 80%) and negative (e.g. 90%) predictive values, respectively. Between 12 weeks and 12 months, the prevalence of Tannerella forsythia increased statistically significantly at implant sites (P<0.05). Lack of detection of Porphyromonas gingivalis at 12 weeks yielded a negative predictive value of 93.1% of this microorganism being undetectable at implant sites at 12 months. CONCLUSIONS: Within the limits of this study, the findings showed (i) a few differences in the prevalence of bacterial species between implant and adjacent tooth sites at 12 months and (ii) high positive and negative predictive values for selected bacterial species.

Performance evaluation and characterization of symmetric capacitors with carbon black, and asymmetric capacitors using a carbon foam supported nickel electrode

This thesis evaluates a novel asymmetric capacitor incorporating a carbon foam supported nickel hydroxide positive electrode and a carbon black negative electrode. A series of symmetric capacitors were prepared to characterize the carbon black (CB) negative electrode. The influence of the binder, PTFE, content on the cell properties was evaluated. X-ray diffraction characterization of the nickel electrode during cycling is also presented. The 3 wt% and 5 wt% PTFE/CB symmetric cells were examined using cyclic voltammetry (CV) and constant current charge/discharge measurements. As compared with symmetric cells containing more PTFE, the 3 wt% cell has the highest average specific capacitance, energy density and power density over 300 cycles, 121.8 F/g, 6.44 Wh/kg, and 604.1 W/kg, respectively. Over the 3 to 10 wt% PTFE/CB range, the 3 wt% sample exhibited the lowest effective resistance and the highest BET surface area. Three asymmetric cells (3 wt% PTFE/CB negative electrode and a nickel positive) were fabricated; cycle life was examined at 3 current densities. The highest average energy and power densities over 1000 cycles were 20 Wh/kg (21 mA/cm2) and 715 W/kg (31 mA/cm2), respectively. The longest cycle life was 11,505 cycles (at 8 mA/cm2), with an average efficiency of 79% and an average energy density of 14 Wh/kg. The XRD results demonstrate that the cathodically deposited nickel electrode is a typical α-Ni(OH)2 with the R3m structure (ABBCCA stacking); the charged electrodes are 3γ-NiOOH with the same stacking as the α-type; the discharged electrodes (including as-formed electrode) are aged to β’-Ni(OH)2 (a disordered β) with the P3m structure (ABAB stacking). A 3γ remnant was observed.

Forget the blood, not the stone! Microhaematuria in acute urolithiasis and the role of early CT scanning

BACKGROUND: Although urinalysis is simple and inexpensive to perform, the finding of microhaematuria on urinalysis may be unreliable for diagnosing urolithiasis. OBJECTIVE: To evaluate microhaematuria as a diagnostic marker for urolithiasis compared with low-dose unenhanced multidetector computed tomography (MDCT) as the "gold standard". SETTING: A level 1 emergency department in a tertiary referral university teaching hospital. DESIGN: Retrospective analysis. METHODS: A study was undertaken to assess whether the finding of microhaematuria was diagnostic for urolithiasis using a low-dose unenhanced MDCT-based diagnosis as the reference standard by reviewing the records of all patients who presented to the emergency department with colicky flank pain and underwent a CT scan between January 2003 and December 2005. RESULTS: Urolithiasis was present (as defined by low-dose unenhanced MDCT) in 507/638 patients (79%); 341/638 (53%) were true positive for urolithiasis, 76 (12%) were true negative, 55 (9%) were false positive and 166 (26%) were false negative. Microhaematuria as a test for urolithiasis in patients presenting to the emergency department therefore has a sensitivity, specificity, positive predictive value and negative predictive value of 67%, 58%, 86% and 31%, respectively. 58% of the urinalysis results were negative for haematuria in the subset of patients with significant alternative diagnoses. CONCLUSIONS: The sensitivity, specificity and negative predictive value of microhaematuria on urinalysis for urolithiasis using unenhanced MDCT as the reference standard were low. This suggests that, when urolithiasis is clinically suspected, unenhanced MDCT is indicated without urinalysis being a prerequisite.

Charge and spin transport in nanoscale junction from first principles

Recently nanoscale junctions consisting of 0-D nanostructures (single molecule) or 1-D nanostructures (semiconducting nanowire) sandwiched between two metal electrodes are successfully fabricated and characterized. What lacks in the recent developments is the understanding of the mechanism behind the observed phenomena at the level of atoms and electrons. For example, the origin of observed switching effect in a semiconducting nanowire due to the influence of an external gate bias is not yet understood at the electronic structure level. On the same context, different experimental groups have reported different signs in tunneling magneto-resistance for the same organic spin valve structure, which has baffled researchers working in this field. In this thesis, we present the answers to some of these subtle questions by investigating the charge and spin transport in different nanoscale junctions. A parameter-free, single particle Green’s function approach in conjunction with a posteriori density functional theory (DFT) involving a hybrid orbital dependent functional is used to calculate the tunneling current in the coherent transport limit. The effect of spin polarization is explicitly incorporated to investigate spin transport in a nanoscale junction. Through the electron transport studies in PbS nanowire junction, a new orbital controlled mechanism behind the switching of the current is proposed. It can explain the switching behavior, not only in PbS nanowire, but in other lead-chalcogenide nanowires as well. Beside this, the electronic structure properties of this nanowire are studied using periodic DFT. The quantum confinement effect was investigated by calculating the bandgap of PbS nanowires with different diameters. Subsequently, we explain an observed semiconducting to metallic phase transition of this nanowire by calculating the bandgap of the nanowire under uniform radial strain. The compressive radial strain on the nanowire was found to be responsible for the metallic to semiconducting phase transition. Apart from studying one dimensional nanostructure, we also present transport properties in zero dimensional single molecular junctions. We proposed a new codoping approach in a single molecular carborane junction, where a cation and an anion are simultaneously doped to find the role of a single atom in the device. The main purpose was to build a molecular junction where a single atom can dictate the flow of electrons in a circuit. Recent observations of both positive and negative sign in tunneling magnetoresistance (TMR) the using same organic spin-valve structure hasmystified researchers. From our spin dependent transport studies in a prototypical organic molecular tunneling device, we found that a 3% change in metal-molecule interfacial distance can alter the sign of TMR. Changing the interfacial distance by 3%, the number of participating eigenstates as well as their orbital characteristic changes for anti-parallel configuration of the magnetization at the two electrodes, leading to the sign reversal of the TMR. Apart from this, the magnetic proximity effect under applied bias is investigated quantitatively, which can be used to understand the observed unexpectedmagnetismin carbon basedmaterials when they are in close proximity with magnetic substrates.

Managerial perseptions on corporate social responsbility: A Transatlantic comparison between forest products companies in Europe and North America

Corporate Social Responsibility (CSR) addresses the responsibility of companies for their impacts on society. The concept of strategic CSR is becoming increasingly mainstreamed in the forest industry, but there is, however, little consensus on the definition and implementation of CSR. The objective of this research is to build knowledge on the characteristics of CSR and to provide insights on the emerging trend to increase the credibility and legitimacy of CSR through standardization. The study explores how the sustainability managers of European and North American forest companies perceive CSR and the recently released ISO 26000 guidance standard on social responsibility. The conclusions were drawn from an analysis of two data sets; multivariate survey data based on one subset of 30 European and 13 North American responses, and data obtained through in-depth interviewing of 10 sustainability managers that volunteered for an hour long phone discussion about social responsibility practices at their company. The analysis concluded that there are no major differences in the characteristics of cross-Atlantic CSR. Hence, the results were consistent with previous research that suggests that CSR is a case- and company-specific concept. Regarding the components of CSR, environmental issues and organizational governance were key priorities in both regions. Consumer issues, human rights, and financial issues were among the least addressed categories. The study reveals that there are varying perceptions on the ISO 26000 guidance standard, both positive and negative. Moreover, sustainability managers of European and North American forest companies are still uncertain regarding the applicability of the ISO 26000 guidance standard to the forest industry. This study is among the first to provide a preliminary review of the practical implications of the ISO 26000 standard in the forest sector. The results may be utilized by sustainability managers interested in the best practices on CSR, and also by a variety of forest industrial stakeholders interested in the practical outcomes of the long-lasting CSR debate.

Sustainability study of nanomaterials including societal and occupational implications

In recent years there has been a tremendous amount of research in the area of nanotechnology. History tells us that the commercialization of technologies will always be accompanied by both positive and negative effects for society and the environment. Products containing nanomaterials are already available in the market, and yet there is still not much information regarding the potential negative effects that these products may cause. The work presented in this dissertation describes a holistic approach to address different dimensions of nanotechnology sustainability. Life cycle analysis (LCA) was used to study the potential usage of polyethylene filled with nanomaterials to manufacture automobile body panels. Results showed that the nanocomposite does not provide an environmental benefit over traditional steel panels. A new methodology based on design of experiments (DOE) techniques, coupled with LCA, was implemented to investigate the impact of inventory uncertainties. Results showed that data variability does not have a significant effect on the prediction of the environmental impacts. Material profiles for input materials did have a highly significant effect on the overall impact. Energy consumption and material characterization were identified as two mainstreams where additional research is needed in order to predict the overall impact of nanomaterials more effectively. A study was undertaken to gain insights into the behavior of small particles in contact with a surface exposed to air flow to determine particle lift-off from the surface. A mapping strategy was implemented that allows for the identification of conditions for particle liftoff based on particle size and separation distance from the wall. Main results showed that particles smaller than 0:1mm will not become airborne under shear flow unless the separation distance is greater than 15 nm. Results may be used to minimize exposure to airborne materials. Societal implications that may occur in the workplace were researched. This research task explored different topics including health, ethics, and worker perception with the aim of identifying the base knowledge available in the literature. Recommendations are given for different scenarios to describe how workers and employers could minimize the unwanted effects of nanotechnology production.

Multiparameter flow cytometry characterization of MHC class I negative mouse bone marrow cells

BACKGROUND: MHC-I down-regulation was described in foetal liver progenitors, and two different subsets of adult bone marrow derived stem cells. These cells, namely, MHC-I-/Thy1+ bone marrow derived liver stem cells (BMDLSC) and the multipotent adult progenitors (MAPC) differentiated into functioning hepatocytes. The aim of this paper was to characterize the MHC-I negative bone marrow compartment as it pertains to BMDLSC and MAPC. MATERIAL/METHODS: We performed multiparameter flow-cytometry analyses of the MHC-I negative compartment using hematopoietic (CD45, Ter119), and stem cell markers (Thy1.2, c-Kit, IL-3R, CD34) in adult mice. RESULTS: When analysing CD45 and Ter119 expression, the MHC-I negative bone marrow compartment divides into four sub-populations: 1. CD45-/Ter119+: 86.0+/-4.4%; 2. CD45+/Ter119+: 0.2+/-0.1%; 3. CD45+/Ter119-: 11.6+/-3.0%; 4. CD45-/Ter119-: 2.0+/-2.1%. Stem cells markers were only expressed on MHC-I negative/ CD45+/Ter119- cells. In vivo, MAPC (Ter119-/CD45- cells) are composed of MHC-I negative (24%) and MHC-I positive cells and do not express any of the stem cell markers tested. CONCLUSIONS: In conclusion, mouse BMDLSC and MAPC are two distinct stem cell populations. Down-regulation of MHC-I was the only common characteristic found between BMDLSC and MAPC suggesting that selection of MHC-I negative cells might represent an efficient strategy to enrich for bone marrow stem cells with liver developmental potential.

Potent and broad-spectrum antimicrobial activity of CXCL14 suggests an immediate role in skin infections

The skin is constantly exposed to commensal microflora and pathogenic microbes. The stratum corneum of the outermost skin layer employs distinct tools such as harsh growth conditions and numerous antimicrobial peptides (AMPs) to discriminate between beneficial cutaneous microflora and harmful bacteria. How the skin deals with microbes that have gained access to the live part of the skin as a result of microinjuries is ill defined. In this study, we report that the chemokine CXCL14 is a broad-spectrum AMP with killing activity for cutaneous gram-positive bacteria and Candida albicans as well as the gram-negative enterobacterium Escherichia coli. Based on two separate bacteria-killing assays, CXCL14 compares favorably with other tested AMPs, including human beta-defensin and the chemokine CCL20. Increased salt concentrations and skin-typical pH conditions did not abrogate its AMP function. This novel AMP is highly abundant in the epidermis and dermis of healthy human skin but is down-modulated under conditions of inflammation and disease. We propose that CXCL14 fights bacteria at the earliest stage of infection, well before the establishment of inflammation, and thus fulfills a unique role in antimicrobial immunity.

Seasonal variation of VO 2 max and the VO2-work rate relationship in elite Alpine skiers

PURPOSE: Alpine ski performance relates closely to both anaerobic and aerobic capacities. During their competitive season, skiers greatly reduce endurance and weight training, and on-snow training becomes predominant. To typify this shift, we compared exhaustive ramp cycling and squat (SJ) and countermovement jumping (CMJ) performance in elite males before and after their competitive season. RESULTS: In postseason compared with preseason: 1) maximal oxygen uptake (VO 2 max) normalized to bodyweight was higher (55.2 +/- 5.2 vs 52.7 +/- 3.6 mL x kg(-1) x min(-1), P < 0.01), but corresponding work rate (W) was unchanged; 2) at ventilatory thresholds (VT), absolute and relative work rates were similar but heart rates were lower; 3) VO2/W slope was greater (9.59 +/- 0.6 vs 9.19 +/- 0.4 mL O2 x min(-1) x W(-1), P = 0.02), with similar flattening (P < 0.01) above V T1 at both time points; and 4) jump height was greater in SJ (47.4 +/- 4.4 vs 44.7 +/- 4.3 cm, P < 0.01) and CMJ (52.7 +/- 4.6 vs 50.4 +/- 5.0 cm, P < 0.01). DISCUSSION: We believe that aerobic capacity and leg power were constrained in preseason and that improvements primarily reflected an in-season recovery from a fatigued state, which was caused by incongruous preseason training. Residual adaptations to high-altitude exposure in preseason could have also affected the results. Nonetheless, modern alpine skiing seemingly provides an ample cardiovascular training stimulus for skiers to maintain their aerobic capacities during the racing season. CONCLUSIONS: We conclude that aerobic fitness and leg explosiveness can be maintained in-season but may be compromised by heavy or excessive preseason training. In addition, ramp test V O2/W slope analysis could be useful for monitoring both positive and negative responses to training.

Psychosocial outcome in cardiovascular rehabilitation of peripheral artery disease and coronary artery disease patients

We investigated patients with a primary diagnosis of peripheral artery disease (n = 69) and coronary heart disease (CAD; n = 520) at baseline and on changes in psychosocial risk factors (depression, anxiety, quality of life, negative and positive affect) during a cardiovascular rehabilitation program. Patients completed psychosocial questionnaires at the beginning and at discharge of a 12-week rehabilitation program. Depression and anxiety were measured with the Hospital Anxiety and Depression Scale (HADS), positive and negative affect with the Global Mood Scale, and health-related quality of life with the SF-36 Health Survey. Patients with PAD showed improvements in anxiety (p < 0.001), negative affect (p < 0.001) and bodily pain (p < 0.001). Patients with CAD reported significant improvements in all measured dimensions (all p-values < 0.001).

Event-related potential P300 microstate topography during visual one- and two-dimensional tasks in chronic schizophrenics

Reports on left-lateralized abnormalities of component P300 of event-related brain potentials (ERP) in schizophrenics typically did not vary task difficulties. We collected 16-channel ERP in 13 chronic, medicated schizophrenics (25±4.9 years) and 13 matched controls in a visual P300 paradigm with targets defined by one or two stimulus dimensions (C1: color; C2: color and tilt); subjects key-pressed to targets. The mean target-ERP map landscapes were assessed numerically by the locations of the positive and negative map-area centroids. The centroids' time-space trajectories were searched for the P300 microstate landscape defined by the positive centroid posterior of the negative centroid. At P300 microstate centre latencies in C1, patients' maps tended to a right shift of the positive centroid (p<0.10); in C2 the anterior centroid was more posterior (p<0.07) and the posterior (positive) centroid more anterior (p<0.03), but without leftright difference. Duration of P300 microstate in C2 was shorter in patients (232 vs 347 ms;p<0.03) and the latency of maximal strength of P300 microstate increased significantly in patients (C1: 459 vs 376 ms; C2: 585 vs 525 ms). In summary only the one-dimensional task C1 supported left-sided abnormalities; the two-dimensional task C2 produced abnormal P300 microstate map landscapes in schizophrenics, but no abnormal lateralization. Thus, information processing involved clearly aberrant neural populations in schizophrenics, different when processing one and two stimulus dimensions. The lack of lateralization in the two-dimensional task supported the view that left-temporal abnormality in schizophrenics is only one of several task-dependent aberrations.

Face-elicited ERPs and affective attitude: brain electric microstate and tomography analyses

Objectives: Although behavioral studies have demonstrated that normative affective traits modulate the processing of facial and emotionally charged stimuli, direct electrophysiological evidence for this modulation is still lacking. Methods: Event-related potential (ERP) data associated with personal, traitlike approach- or withdrawal-related attitude (assessed post-recording and 14 months later) were investigated in 18 subjects during task-free (i.e. unrequested, spontaneous) emotional evaluation of faces. Temporal and spatial aspects of 27 channel ERP were analyzed with microstate analysis and low resolution electromagnetic tomography (LORETA), a new method to compute 3 dimensional cortical current density implemented in the Talairach brain atlas. Results: Microstate analysis showed group differences 132-196 and 196-272 ms poststimulus, with right-shifted electric gravity centers for subjects with negative affective attitude. During these (over subjects reliably identifiable) personality-modulated, face-elicited microstates, LORETA revealed activation of bilateral occipito-temporal regions, reportedly associated with facial configuration extraction processes. Negative compared to positive affective attitude showed higher activity right temporal; positive compared to negative attitude showed higher activity left temporo-parieto-occipital. Conclusions: These temporal and spatial aspects suggest that the subject groups differed in brain activity at early, automatic, stimulus-related face processing steps when structural face encoding (configuration extraction) occurs. In sum, the brain functional microstates associated with affect-related personality features modulate brain mechanisms during face processing already at early information processing stages.