Design of a multi-detector, single line-of-sight, time-of-flight system to measure time-resolved neutron energy spectra.

In the dynamic environment of burning, thermonuclear deuterium-tritium plasmas, diagnosing the time-resolved neutron energy spectrum is of critical importance. Strategies exist for this diagnosis in magnetic confinement fusion plasmas, which presently have a lifetime of ∼1012 longer than inertial confinement fusion (ICF) plasmas. Here, we present a novel concept for a simple, precise, and scale-able diagnostic to measure time-resolved neutron spectra in ICF plasmas. The concept leverages general tomographic reconstruction techniques adapted to time-of-flight parameter space, and then employs an updated Monte Carlo algorithm and National Ignition Facility-relevant constraints to reconstruct the time-evolving neutron energy spectrum. Reconstructed spectra of the primary 14.028 MeV nDT peak are in good agreement with the exact synthetic spectra. The technique is also used to reconstruct the time-evolving downscattered spectrum, although the present implementation shows significantly more error.

Vietnamese community screening for hepatitis B virus and hepatitis C virus.

Asian Americans represent an important cohort at high risk for viral hepatitis. To determine the prevalence of Hepatitis B virus (HBV) and Hepatitis C virus (HCV) infection and HBV vaccination in a Vietnamese community, a total of 322 Vietnamese subjects from a local doctor's office and annual Vietnamese Health Fair were included in this study. Demographic and clinical data were collected. 2.2% of the screened cohort tested positive for anti-HCV and 9.3% tested positive for HBsAg. Unlike HBV-positive subjects, HCV-positive subjects had significantly higher liver enzymes (P = 0.0045 and P = 0.0332, respectively). The HBV-positive group was more likely to report jaundice (P = 0.0138) and a family history of HBV (P = 0.0115) compared to HBV-negative subjects. Forty-eight patients (15.5%) reported a family history of liver disease (HBV, HCV, HCC, cirrhosis, other). Of this 48, 68.8% reported no personal history of HBV vaccination and 77.1% reported no family history of vaccination for HBV. Among the 183 subjects without a family history of liver disease, 156 (85.2%) reported no personal history of vaccination and 168 (91.8%) reported no family history of vaccination. HBV vaccination rates in those reporting a family history of liver disease were significantly higher (P =0.020). There was a high prevalence of HBV infection in this community screening. Nevertheless, the rate for HBV vaccination was low. The low prevalence of abnormal liver enzymes in HBV-positive subjects emphasizes the need for screening to be triggered by risk factors and not by abnormal liver enzymes.

High density Langmuir probe array for NSTX scrape-off layer measurements under lithiated divertor conditions.

A high density Langmuir probe array has been developed for measurements of scrape-off layer parameters in NSTX. Relevant scale lengths for heat and particle fluxes are 1-5 cm. Transient edge plasma events can occur on a time scale of several milliseconds, and the duration of a typical plasma discharge is ∼1 s. The array consists of 99 individual electrodes arranged in three parallel radial rows to allow both swept and triple-probe operation and is mounted in a carbon tile located in the lower outer divertor of NSTX between two segments of the newly installed liquid lithium divertor. Initial swept probe results tracking the outer strike point through probe flux measurements are presented.

Biasing, acquisition, and interpretation of a dense Langmuir probe array in NSTX.

A dense array of 99 Langmuir probes has been installed in the lower divertor region of the National Spherical Torus Experiment (NSTX). This array is instrumented with a system of electronics that allows flexibility in the choice of probes to bias as well as the type of measurement (including standard swept, single probe, triple probe, and operation as passive floating potential and scrape-off-layer SOL current monitors). The use of flush-mounted probes requires careful interpretation. The time dependent nature of the SOL makes swept-probe traces difficult to interpret. To overcome these challenges, the single- and triple-Langmuir probe signals are used in complementary fashion to determine the temperature and density at the probe location. A comparison to midplane measurements is made.

Predictors of health-related quality of life in patients with chronic liver disease.

BACKGROUND: Patient-reported outcomes like health-related quality of life (HRQL) have become increasingly important for full assessment of patients with chronic liver diseases (CLD). AIM: To explore the relative impact of different types of liver disease on HRQL as well as predictors of HRQL domains in CLD. METHODS: Our HRQL databases with Short-Form 36 (SF-36) data were used. Scores for each of SF-36 scales (PF - physical functioning, RP - role functioning, BP - bodily pain, GH - general health, VT - vitality, SF - social functioning, RE - role emotional and MH - mental health, MCS - mental component score, PCS - physical component score) were compared between different types of CLD as well as other variables. RESULTS: Complete data were available for 1103 CLD patients. Demographic and clinical data included: age 54.2 +/- 12.0 years, 40% female, 761 (69%) with cirrhosis. Analysis revealed that age correlated significantly (P < 0.05) with worsening HRQL on every scale of the SF-36. Female patients had more HRQL impairments in PF, RP, BP, GH, VT and MH scales of SF-36 (Delta scale score: 6.6-10.7, P < 0.05). Furthermore, cirrhotic patients had more impairment of HRQL in every scale of SF-36 (Delta scale score: 6.6-43.0, P < 0.05). In terms of diagnostic groups, non-alcoholic fatty liver disease patients showed more impairment of HRQL. CONCLUSIONS: Analysis of this large CLD cohort suggests that a number of important clinicodemographic factors are associated with HRQL impairment. These findings contribute to the full understanding of the total impact of CLD on patients' health.

Screening for hepatitis B, C and non-alcoholic fatty liver disease: a survey of community-based physicians.

BACKGROUND: Screening guidelines for hepatitis B (HBV) and hepatitis C viruses (HCV) as well as a position statement for non-alcoholic fatty liver disease (NAFLD) have been put forth by different sources, but awareness of these guidelines and their impact on the physician practices have not been assessed. AIM: To assess the attitudes of primary care physicians (PCPs), gastroenterologists (GEs) and hepatologists (HEPs) regarding screening for HBV, HCV and NAFLD. DESIGN: A survey questionnaire was sent to community-based PCPs and GEs to assess issues related to HBV, HCV and NAFLD. The same questionnaire was sent to hepatologists (HEPs). The questionnaire contained 10 items related to demographic and practice patterns of these physicians, 35 items related to HBV, 35 items related to HCV and 29 items related to NAFLD. RESULTS: A total of 214 physicians (103 PCPs, 59 GEs and 52 HEPs) completed the survey. A majority of PCPs, GEs and HEPs agreed on most screening issues for these causes of liver disease. Nevertheless, within group comparison of physicians (guideline aware versus guideline unaware) showed significant differences in accurate response between those who were aware of guidelines and those who were not aware. CONCLUSIONS: A large percentage of PCPs and GEs were unaware of official guidelines for viral hepatitis B and hepatitis C. Those aware of guidelines were more likely to screen appropriately and avoid unnecessary testing. More needs to be done to assess awareness and the impact implementation of guidelines in hepatology.

Health-related quality of life in patients with non-alcoholic fatty liver disease.

BACKGROUND: The relative impact of non-alcoholic fatty liver disease (NAFLD) on health-related quality of life (HRQL) compared to other chronic liver diseases has not been fully explored. AIM: To compare the domain scores of the 29-item Chronic Liver Disease Questionnaire (CLDQ) for patients with NAFLD to those with chronic hepatitis B and chronic hepatitis C. METHODS: A HRQL questionnaire, CLDQ, was routinely administered to patients attending a liver clinic. Additional clinical and laboratory data were obtained on patients with NAFLD, chronic hepatitis B, and chronic hepatitis C from our quality of life database. Scores for each of the six CLDQ domains were compared using one-way anova and multiple regression. RESULTS: Complete data were available for 237 patients. NAFLD patients scored lowest on multiple CLDQ domains. Based on the bivariate data, NAFLD patients have the poorest HRQL, followed by chronic hepatitis C and chronic hepatitis B patients. Multivariate analysis showed that some specific domain score correlations remained significant for NAFLD diagnosis, cirrhosis, gender, and body mass index. CONCLUSION: NAFLD patients had significantly lower quality of life scores compared with patients with hepatitis B or hepatitis C on multiple CLDQ domains, suggesting that HRQL was severely impaired in patients with NAFLD.

Incidence, microbiological findings, and clinical presentation of sternal wound infections after cardiac surgery with and without local gentamicin prophylaxis.

Sternal wound infection (SWI) is a serious complication after cardiac surgery. In a previous randomized controlled trial, the addition of local collagen-gentamicin in the sternal wound before wound closure was found to significantly reduce the incidence of postoperative wound infections compared with the routine intravenous prophylaxis of isoxazolyl-penicillin only. The aims of the present study were to analyse the microbiological findings of the SWIs from the previous trial as well as to correlate these findings with the clinical presentation of SWI. Differences in clinical presentation of SWIs, depending on the causative agent, could be identified. Most infections had a late, insidious onset, and the majority of these were caused by staphylococci, predominantly coagulase-negative staphylococci. The clinically most fulminant infections were caused by gram-negative bacteria and presented early after surgery. Local administration of gentamicin reduced the incidence of SWIs caused by all major, clinically important bacterial species. Propionibacterium acnes was identified as a possible cause of SWI and may be linked to instability in the sternal fixation. There was no indication of an increase in the occurrence of gentamicin-resistant bacterial isolates in the treatment group. Furthermore, the addition of local collagen-gentamicin reduced the incidence of SWIs caused by methicillin-resistant coagulase-negative staphylococci. This technique warrants further evaluation as an alternative to prophylactic vancomycin in settings with a high prevalence of methicillin-resistant Staphylococcus aureus.

Influence of more than six sternal fixation wires on the incidence of deep sternal wound infection.

BACKGROUND: The aim of the present study was to examine the influence of the number of sternal fixation wires used on deep sternal wound infection rate and to analyze any possible interaction between this and local collagen-gentamicin prophylaxis evaluated in a previous trial. METHODS: The number of sternal fixation wires in all patients from one of two participating centers was counted. The patients were categorized according to six or fewer (standard technique, ST group) vs. seven or more wires (extra wires, XW group). RESULTS: The incidence of deep sternal wound infection was 4.2 % in the ST group and 0.4 % in the XW group ( P = 0.001). An analysis of the effect of local gentamicin, excluding the ST group from the analysis, showed an approximately 70 % reduction in sternal wound infection for all depths. CONCLUSION: This study supports the theory that additional fixation wires at the lower sternum actually reduce the incidence of deep wound infections. We suggest that a rigid sternal fixation is required to achieve the full benefit of local collagen-gentamicin prophylaxis.

Human neutrophil lipocalin: normal levels and use as a marker for invasive infection in the newborn.

AIM: To evaluate human neutrophil lipocalin (HNL) as a marker of neonatal invasive infection and determine the normal serum levels of HNL in newborns. METHODS: HNL is released from neutrophil granulocytes and is regarded as a specific marker of neutrophil activity. In 81 newborns < or = 28 d of age with signs of infection on a total of 87 occasions, HNL and C-reactive protein (CRP) were measured at inclusion and on the three following days. As controls, term healthy newborns were recruited at birth (cord blood, n = 45) and at ages 3-5 d (n = 46). Serum HNL was measured by a radioimmunoassay. RESULTS: 25/87 episodes were classified as infection and 62 as non-proven infection. HNLmax was significantly higher in the infected group (mean 587.6 microg/l) than in the non-proven infected group (mean 217.7 microg/, p < 0.001). HNL peaked at inclusion, 1 d earlier than CRP. In the healthy controls. HNL was the same at 3-5 d of age as at birth (mean 82.4-81.7 microg/l) and similar to normal adult levels. CONCLUSIONS: The release of HNL is not increased in healthy newborns at birth, but neonatal neutrophils rapidly release HNL upon microbial stimulation in vivo. HNL might be useful as an early marker of neonatal infection.

Contribution of interleukin-6 in distinguishing between mild respiratory disease and neonatal sepsis in the newborn infant.

The purpose of this study was to investigate if early samples of interleukin-6 (IL-6) could distinguish early bacterial sepsis from respiratory diseases in the newborn. IL-6 and C-reactive protein (CRP) were measured at onset of symptoms in newborns evaluated for sepsis during the first week of life. Five groups of children were investigated: proven sepsis, clinical sepsis, respiratory distress syndrome (RDS), transient tachypnoea of the newborn (TTN) and controls. IL-6 was also analysed at the time when CRP was at its maximum level. The results showed that initial IL-6 distinguished proven and clinical sepsis from TTN, but not from RDS. Initial CRP was of no value for diagnosis. Our conclusion is that early IL-6 makes it possible to avoid antibiotics in children with TTN and contributes to the diagnosis of sepsis faster than CRP.

Aesthetic implications of surgical anatomy in blepharoplasty.

A successful outcome in rejuvenation surgery of the orbital region relies on a well-developed sense of the aesthetic goal and a critical understanding of the underlying anatomic basis for the deviation from this goal in a given patient. As the surgeon assesses the patient to determine the approach to achieve the best aesthetic result, careful consideration to both form and function must be undertaken. In this article we consider the orbital region by anatomic subunit with special attention to the anatomic causes for deviations from the aesthetic ideal. Exacting preoperative assessment of the patient's presenting anatomy is critical in guiding the surgeon to a proper approach. A conservative approach helps to minimize the risk of complications, which have both functional and aesthetic consequences. The implications of the specific anatomy for the surgical options to achieve the most desirable aesthetic result are discussed.

Impaired phagocytosis and opsonisation towards group B streptococci in preterm neonates.

AIMS: To study the chemiluminescence response in polymorphonuclear leucocytes (PMNL) at different stages of maturity and the opsonic capacity of sera with defined titres of anti-capsular type III antibodies, after exposure to serotype III group B streptococci (GBS). The influence of GBS type III capsule expression on PMNL chemiluminescence response was also investigated. METHODS: Two clinical isolates of serotype III GBS and two serotype III reference strains which form isogenic variants with high and low amounts of capsule substance, respectively, were used. PMNL and sera were obtained from adult healthy blood donors, full term neonates, and preterm neonates. RESULTS: PMNL from premature infants showed a significantly lower chemiluminescence response (p < 0.0001) than the PMNL from adults and neonates, while the chemiluminescence response with adult, neonatal, and preterm sera gradually diminished. In the presence of a serum pool with a standardised complement value, raised (> 10 mg/l), rather than low (< 1.0 mg/l) anti-III antibody titres induced a higher chemiluminescence response to the capsule expressing variant. When GBS were cultured at pH 5.0, the bacteria had a higher buoyant density, reflecting decreased expression of capsule substance compared with bacteria grown at pH 7.4. Concomitantly, there was a substantial increase in chemiluminescence response for all isolates cultured at the lower pH, except for the capsule deficient mutant. CONCLUSIONS: PMNL function and opsonic capacity are significantly impaired in neonates and correlate with maturation of the newborn child. The combined defect in cellular and humoral defences in preterm neonates may contribute to their increased susceptibility to GBS infection. Growth conditions for GBS, simulating different in vivo environments, greatly affect capsule expression and resistance to phagocytosis.

Secretion of IL-6, IL-8 and G-CSF by human endothelial cells in vitro in response to Staphylococcus aureus and staphylococcal exotoxins.

The capacity of endothelial cells to produce and release cytokines (IL-6, IL-8 and G-CSF) in response to exposure to Staphylococcus aureus strains or staphylococcal exotoxins (alpha-toxin, enterotoxin A and TSST-1) was investigated. An endothelial cell culture model of human umbilical vein endothelial cells (HUVEC) was used. Five out of ten clinical isolates of S. aureus were found to induce cytokine production and release from endothelial cells. Four of the five isolates that induce cytokine release produced enterotoxin A, B, C, D and/or TSST-1, compared with two of those that did not induce release. Purified staphylococcal exotoxins (1 pg/ml-1 microg/ml) did not act as primary stimuli and induced no detectable cytokine secretion. When endothelial cells were prestimulated with IL-1beta or TNF alpha at a concentration of 1 ng/ml for 2 h, IL-1beta served as a potent primary stimulus for IL-6, IL-8 and G-CSF production, whereas TNF alpha did not induce any significant cytokine release during the subsequent 24 h. A further increase in IL-6 and G-CSF release, but not of IL-8, was observed when IL-1beta prestimulated cells were exposed to alpha-toxin or TSST-1. However, to potentiate cytokine production (IL-6 and IL-8) by SEA, both IL-1beta and the toxin had to be present simultaneously. Our data show that S. aureus, but not staphylococcal exotoxins, have the capacity to act as primary stimuli of endothelial cells and induce production and release of cytokines. IL-1beta may prime HUVEC to release IL-6, IL-8 and G-CSF prior to subsequent stimulation with staphylococcal exotoxins.

Penetration of group B streptococci through polarized Madin-Darby canine kidney cells.

Group B streptococci (GBS) are one of the major causes of invasive neonatal infection. The pathogenesis of early onset disease is a multistep process. Adhesion of GBS to eucaryotic cells is considered to be an important step for the establishment of infection. Subsequent to adhesion, GBS invade cells and give rise to septicemia and meningitis. To investigate passage of GBS across epithelial cell linings we examined the interaction between bacteria and Madin-Darby canine kidney (MDCK) cells. When grown on permeable support, these cells form a polarized epithelial monolayer with an apical-to-basolateral orientation, which more reflects the in vivo situation compared with conventionally cultured cells. Our results show that GBS are translocated in vacuoles from the apical to the basolateral surface of MDCK cells in a temperature-dependent process. The passage of GBS through the cells is selective with only small numbers of bacteria penetrating in the basolateral-to-apical direction. Transcytosis of GBS starts before decrease in transepithelial resistance of the monolayer. These data suggest a mechanism for traversal of GBS over intact chorioamniotic membranes and from alveoli into the circulation of the fetus.

Increase of staphylococci in neonatal septicaemia: a fourteen-year study.

All cases of neonatal septicaemia during 1981-94 were studied at Orebro Medical Centre Hospital, Sweden. One hundred and thirty-two children fulfilled laboratory and clinical criteria for neonatal septicaemia and were included. Staphylococcus aureus (n = 41), Group B streptococcus (GBS) (n = 32) and coagulase-negative staphylococci (CoNS) (n = 27) were the dominating aetiologies. The annual incidence of septicaemia increased significantly, from 2.3 cases during the first 7-year period to 3.3 per 1000 live births during 1988-94. This increase was caused by S. aureus and CoNS, which mainly affected premature children and had an onset more than 48 h after delivery. GBS, on the other hand, slightly decreased and affected full-term children within 48 h. The overall mortality was 11%. CoNS isolated during the latter 7-year period were more resistant to antibiotics than those isolated during 1981-87; resistance to methicillin increased from 14 to 45% and to gentamicin from 0 to 20%. These changes in aetiology and antibiotic susceptibility should be considered when selecting antibiotic treatment in neonatal septicaemia.

Laser diode to single-mode fiber ball lens coupling efficiency: full-wave calculation and measurements.

We show that the coupling efficiency from a laser diode (LD) to an optical fiber through a ball lens can be calculated accurately using the exact solution to Maxwell's equations for the scattering of a beam from a dielectric sphere. Our calculated results agree closely with coupling measurements from an asymmetric LD for two different ball lenses.

Computed tomography in lacrimal outflow obstruction.

BACKGROUND: Acquired nasolacrimal duct obstruction is a common ophthalmologic problem. Despite widespread understanding of treatments available for nasolacrimal duct obstruction, few authors have commented on its etiology. Because the nasolacrimal system is anatomically related to important nasal and sinus structures, the authors postulated that acquired nasolacrimal duct obstruction and its complications might occur simultaneous to, and possibly as a consequence of, rhinologic or sinus disease. MATERIALS AND METHODS: Twenty-three patients with acquired nasolacrimal duct obstruction and 100 control patients were evaluated by coronal computed tomography for evidence of sinus disease or nasal abnormalities. Specifically, five findings were noted: ostiomeatal complex disease, ethmoidal opacification, agger nasi cell opacification, concha bullosa, and nasal septal deviation. RESULTS: Overall, 20 (87%) patients with acquired nasolacrimal duct obstruction demonstrated one or more radiologic finding of sinus disease or rhinologic abnormality whereas 63 (63%) control subjects exhibited these findings. This difference was determined to be statistically significant (P < 0.05). A statistically significant higher incidence of ethmoidal opacification, agger nasi cell opacification, and nasal septal deviation was observed in patients with nasolacrimal outflow obstruction than in controls. Differences in the incidence of ostiomeatal complex disease and concha bullosa were not found to be statistically significant. CONCLUSION: These data demonstrate a correlation between computed tomography findings of sinus disease or nasal abnormality and the presence of acquired nasolacrimal outflow obstruction. This association between radiologic evidence of sinorhinologic disorders and lacrimal outflow obstruction may imply that dacryocystitis, like sinus disease, may be produced by disease of the lateral nasal wall. When evaluating a patient with acquired nasolacrimal duct obstruction, the physician should consider evaluation for concomitant nasal and sinus disease.