Synchronized beamline at FLASH2 based on high-order harmonic generation for two-color dynamics studies.

We present the design, integration, and operation of the novel vacuum ultraviolet (VUV) beamline installed at the free-electron laser (FEL) FLASH. The VUV source is based on high-order harmonic generation (HHG) in gas and is driven by an optical laser system synchronized with the timing structure of the FEL. Ultrashort pulses in the spectral range from 10 to 40 eV are coupled with the FEL in the beamline FL26, which features a reaction microscope (REMI) permanent endstation for time-resolved studies of ultrafast dynamics in atomic and molecular targets. The connection of the high-pressure gas HHG source to the ultra-high vacuum FEL beamline requires a compact and reliable system, able to encounter the challenging vacuum requirements and coupling conditions. First commissioning results show the successful operation of the beamline, reaching a VUV focused beam size of about 20 µm at the REMI endstation. Proof-of-principle photo-electron momentum measurements in argon indicate the source capabilities for future two-color pump-probe experiments.

The substantial personal burden experienced by younger people with hip or knee osteoarthritis.

OBJECTIVE: To compare Health-Related Quality of Life (HRQoL) and psychological distress in younger people with hip or knee osteoarthritis (OA) to age- and sex-matched population norms, and evaluate work limitations in this group. METHOD: People aged 20-55 years with hip or knee OA were recruited from major hospitals (n = 126) and community advertisements (n = 21). HRQoL was assessed using the Assessment of Quality of Life (AQoL) instrument (minimal important difference 0.06 AQoL units) and compared to population norms. Psychological distress was assessed using the Kessler Psychological Distress Scale (K10) and the prevalence of high/very high distress (K10 score ≥22) was compared to Australian population data. Work limitations were evaluated using the Workplace Activity Limitations Scale (WALS). RESULTS: Considering most participants had a relatively recent OA diagnosis (<5 years), the extent of HRQoL impairment was unexpected. A very large reduction in HRQoL was evident for the overall sample, compared with population norms (mean difference -0.35 AQoL units, 95% CI -0.40 to -0.31). Females, people aged 40-49 years, and those with hip OA reported average HRQoL impairment of almost 40% (mean reductions -0.38 to -0.39 AQoL units). The overall prevalence of high/very high distress was 4 times higher than for the population (relative risk 4.19, 95% CI 3.53-4.98) and 67% reported moderate to considerable OA-related work disability, according to WALS scores. CONCLUSIONS: These results clearly demonstrate the substantial personal burden experienced by younger people with hip or knee OA, and support the provision of targeted services to improve HRQoL and maximise work participation in this group.

Resolving small signal measurements in experimental plasma environments using calibrated subtraction of noise signals.

The performance of many diagnostic and control systems within fusion and other fields of research are often detrimentally affected by spurious noise signals. This is particularly true for those (such as radiation or particle detectors) working with very small signals. Common sources of radiated and conducted noise in experimental fusion environments include the plasma itself and instrumentation. The noise complicates data analysis, as illustrated by noise on signals measured with the heavy ion beam probe (HIBP) installed on the Madison Symmetric Torus. The noise is time-varying and often exceeds the secondary ion beam current (in contrast with previous applications). Analysis of the noise identifies the dominant source as photoelectric emission from the detectors induced by ultraviolet light from the plasma. This has led to the development of a calibrated subtraction technique, which largely removes the undesired temporal noise signals from data. The advantages of the technique for small signal measurement applications are demonstrated through improvements realized on HIBP fluctuation measurements.

Unnecessary repeat Clostridium difficile PCR testing in hospitalized adults with C. difficile-negative diarrhea.

The aim of this study was to determine the extent and associated costs of repeat Clostridium difficile stool polymerase chain reaction (PCR) assays in patients with initially negative PCRs. C. difficile stool PCRs were done on adult hospitalized patients with diarrhea. The number/time course of repeat PCRs on initially negative PCR patients was determined. Of 5,027 C. difficile stool PCRs, 814 (16.2 %) were positive and 4,213 (83.8 %) were negative. Ninety-seven of the initially PCR-negative patients had >2 repeat tests 1-59 days after the initial negative stool PCR. Repeat negative PCR testing rarely resulted in a subsequent positive result (0.05 %). The unnecessary costs of 97 repeat PCRs was $32,658.00. Many of these patients were originally given empiric oral anti-C. difficile therapy, in spite of repeatedly negative PCRs.

Heavy ion beam probe operation in time varying equilibria of improved confinement reversed field pinch discharges.

Operation of a heavy ion beam probe (HIBP) on a reversed field pinch is unique from other toroidal applications because the magnetic field is more temporal and largely produced by plasma current. Improved confinement, produced through the transient application of a poloidal electric field which leads to a reduction of dynamo activity, exhibits gradual changes in equilibrium plasma quantities. A consequence of this is sweeping of the HIBP trajectories by the dynamic magnetic field, resulting in motion of the sample volume. In addition, the plasma potential evolves with the magnetic equilibrium. Measurement of the potential as a function of time is thus a combination of temporal changes of the equilibrium and motion of the sample volume. A frequent additional complication is a nonideal balance of ion current on the detectors resulting from changes in the beam trajectory (magnetic field) and energy (plasma potential). This necessitates use of data selection criteria. Nevertheless, the HIBP on the Madison Symmetric Torus has acquired measurements as a function of time throughout improved confinement. A technique developed to infer the potential in the improved confinement reversed field pinch from HIBP data in light of the time varying plasma equilibrium will be discussed.

Computer simulation of three-dimensional heavy ion beam trajectory imaging techniques used for magnetic field estimation.

A magnetic field mapping technique via heavy ion beam trajectory imaging is being developed on the Madison Symmetric Torus reversed field pinch. This paper describes the computational tools created to model camera images of the light emitted from a simulated ion beam, reconstruct a three-dimensional trajectory, and estimate the accuracy of the reconstruction. First, a computer model is used to create images of the torus interior from any candidate camera location. It is used to explore the visual field of the camera and thus to guide camera parameters and placement. Second, it is shown that a three-dimensional ion beam trajectory can be recovered from a pair of perspectively projected trajectory images. The reconstruction considers effects due to finite beam size, nonuniform beam current density, and image background noise. Third, it is demonstrated that the trajectory reconstructed from camera images can help compute magnetic field profiles, and might be used as an additional constraint to an equilibrium reconstruction code, such as MSTFit.

Appropriateness of empiric gentamicin and vancomycin therapy for bacteremias in chronic dialysis outpatient units in the era of antibiotic resistance.

Bacteremias in inpatient chronic HD units have been described, but there is little information on bacteremias in ambulatory HD units. To determine the frequency of bacteremia and pathogen distribution in ambulatory chronic HD units, we retrospectively reviewed our experience with 107 bacteremias in 5 chronic ambulatory HD units over a 3 year period. The object of the study was twofold. The first objective was to determine if bacteremias in ambulatory HD setting were substantially different in frequency or type than in the inpatient HD setting. Secondly, febrile patients suspected of having bacteremia in chronic HD patients are often empirically treated with vancomycin and gentamicin. Chronic HD patients require repeated and frequent venous access for HD. Bacteremias are common in chronic HD patients and may be primary or secondary and are often related to venous access site infections. The distributions of bacteremia pathogens in chronic HD patients are predominantly reflective of skin flora, i.e., staphylococci and to lesser extent aerobic Gram-negative bacilli. After S. aureus (MSRA/MSSA) and coagulase-negative staphylococcus (CoNS), enterococci are the next most important Gram-positive pathogens in bacteremic HD patients. Most strains of E. faecalis are sensitive to vancomycin and for practical purposes should be considered as vancomycin sensitive enterococci (VSE). In contrast, most strains of E. faecium are resistant to vancomycin and should be considered as vancomycin resistant enterococci (VRE). We retrospectively reviewed 107 patients on chronic ambulatory HD to determine the adequacy of empiric vancomycin and gentamicin prophylaxis. We found amikacin is preferred to gentamicin and that meropenem is an effective alternate substitution for gentamicin and vancomycin combination therapy.

Core electrostatic fluctuations and particle transport in a reversed-field pinch.

Potential and electron-density fluctuation profiles, phi(r) and ñ(e)(r)/n(e), are measured for the first time in the core of a reversed-field pinch using a heavy ion beam probe. It is found that the fluctuations are broadband and correlated with the core resonant m/n=1/6 tearing mode. The electrostatic-fluctuation-induced particle transport in the core of standard RFP plasmas, estimated from measured <ñ(e)phi>, is small compared to the total particle flux. Measurements of fluctuations and estimates of fluctuation induced particle transport in improved confinement RFP discharges are also presented.

Activities of bismuth thiols against staphylococci and staphylococcal biofilms.

Indwelling medical devices are associated with infectious complications. Incorporating antimicrobials into indwelling materials may reduce bacterial colonization. Bismuth thiols are antibiofilm agents with up to 1,000-fold-greater antibacterial activity than other bismuth salts. Staphylococci are particularly sensitive, as determined by agar diffusion and broth dilution susceptibility testing. Bismuth-ethanedithiol inhibited 10 methicillin-resistant Staphylococcus epidermidis strains at 0.9 to 1.8, Staphylococcus aureus ATCC 25923 at 2.4, and S. epidermidis ATCC 12228 at 0.1 microM Bi(3+). Antiseptic-resistant S. aureus was sensitive to bismuth-2-3-dimercaptopropanol (BisBAL) at < or = 7 microM Bi(3+). Hydrogel-coated polyurethane rods soaked in BisBAL inhibited S. epidermidis for 39 days (inhibitory zone diameter in agar, > or = 30 mm for > 25 days). Slime from 16 slime-producing S. epidermidis strains was inhibited significantly by bismuth-3,4-dimercaptotoluene (BisTOL), but not by AgNO3, at subinhibitory concentrations. In conclusion, bismuth-thiols are bacteriostatic and bactericidal against staphylococci, including resistant organisms, but are also inhibitors of slime at subinhibitory concentrations. At subinhibitory concentrations, BisTOL may be useful in preventing the colonization and infection of indwelling intravascular lines, since staphylococci are important pathogens in this setting.

Necrotizing fasciitis caused by Aeromonas hydrophila.

Aeromonas Hydrophila is a gram-negative bacillus commonly found in soil, sewage, and fresh or brackish water in many parts of the United States. In healthy people, the most common clinical manifestations attributed to Aeromonas are diarrhea and soft tissue infections. In people with suppressed immune systems or liver disease, A hydrophila can cause meningitis, endocarditis, peritonitis, hemolytic-uremic syndrome, or septicemia. We present the first known case of fulminant necrotizing fasciitis from A hydrophila that is not associated with trauma, liver disease, or immunosuppression.

Efficient operation of a high-volume anticoagulation clinic.

A pharmacist-operated anticoagulation clinic at a Department of Veterans Affairs (VA) medical center is described. An anticoagulation clinic established by the pharmacy service at the Denver VA Medical Center cares for 600 patients by using 1.35 fulltime-equivalent pharmacists. The pharmacists are privileged by medical staff to write prescriptions for warfarin, adjust warfarin dosages, and conduct appropriate laboratory monitoring. A protocol has been developed to standardize care. Patients referred to the clinic are scheduled for a same-day warfarin class and laboratory so that International Normalized Ratios (INRs) are available for the patient's appointment with the pharmacist; the patient's understanding of the material presented in the class is assessed during this appointment. The pharmacist determines the therapeutic range and duration of treatment and schedules a follow-up appointment. A locally developed computer program imports patient data from the hospitalwide computer system and simplifies scheduling and tracking of patient-related information. At any point in time, approximately 67% of clinic patients are in the therapeutic range, 13% are above range, and 20% are below range. From January to December 1994, 1.1% of clinic patients were admitted to the medical center for bleeding compared with 2.0% of patients receiving usual care, and 0.9% of clinic patients had thromboembolic complications compared with 3.1% of usual care patients. A computer program, clinical privileging of pharmacists, and a clinic protocol have helped a pharmacist-operated anticoagulation clinic to provide efficient care to veterans.

Proteus penneri urosepsis in a patient with diabetes mellitus.

Proteus penneri has been isolated from many different clinical sources, including surgical wound infections, urine, and blood. We describe the first reported case of P. penneri nosocomial urosepsis in a patient with diabetes. P. penneri was subsequently isolated from bronchoalveolar lavage fluid and a pulmonary artery catheter tip.

Enhancement of bismuth antibacterial activity with lipophilic thiol chelators.

The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of bacteria. The activity, solubility, and stability of BisBAL were strongly dependent on the pH, temperature, and molar ratio. Chelation of bismuth with certain thiol agents enhanced the solubility and lipophilicity of this cationic heavy metal, thereby significantly enhancing its potency and versatility as an antibacterial agent.