Electrostatic design and conditioning of a triple point junction shield for a -200 kV DC high voltage photogun.

Nuclear physics experiments performed at the Continuous Electron Beam Accelerator Facility (CEBAF) at the Jefferson Lab require a DC high voltage photogun to generate polarized electron beams from GaAs photocathodes. The photogun uses a tapered ceramic insulator that extends into the vacuum chamber and mechanically holds the cathode electrode. Increasing the operating voltage from nominal -130 kV to -200 kV will provide lower beam emittance, better transmission through injector apertures, and improved photocathode lifetime. This desire to increase the photogun operating voltage led to the design of a triple-point-junction shield electrode which minimizes the electric field at the delicate insulator-metal-vacuum interface and linearizes the potential across the insulator, thus reducing the risk of arcing along the ceramic insulator. This work describes the results obtained using COMSOL® electrostatic-field simulation software and presents the high voltage conditioning results of the upgraded -200 kV CEBAF photogun.

High voltage performance of a dc photoemission electron gun with centrifugal barrel-polished electrodes.

The design and fabrication of electrodes for direct current (dc) high voltage photoemission electron guns can significantly influence their performance, most notably in terms of maximum achievable bias voltage. Proper electrostatic design of the triple-point junction shield electrode minimizes the risk of electrical breakdown (arcing) along the insulator-cable plug interface, while the electrode shape is designed to maintain <10 MV/m at the desired operating voltage aiming at little or no field emission once conditioned. Typical electrode surface preparation involves diamond-paste polishing by skilled personnel, requiring several weeks of effort per electrode. In this work, we describe a centrifugal barrel-polishing technique commonly used for polishing the interior surface of superconducting radio frequency cavities but implemented here for the first time to polish electrodes for dc high voltage photoguns. The technique reduced polishing time from weeks to hours while providing surface roughness comparable to that obtained with diamond-paste polishing and with unprecedented consistency between different electrode samples. We present electrode design considerations and high voltage conditioning results to 360 kV (∼11 MV/m), comparing barrel-polished electrode performance to that of diamond-paste polished electrodes. Tests were performed using a dc high voltage photogun with an inverted-geometry ceramic insulator design.

The Lifeways Cross-Generation Study: design, recruitment and data management considerations.

The Lifeways Cross-Generation Cohort Study was first established in 2001 and is a unique longitudinal database in Ireland, with currently over three and a half thousand family participants derived from 1124 mothers recruited initially during pregnancy, mainly during 2002. The database comprises a) baseline self-reported health data for all mothers, a third of fathers and at least one grandparent b) clinical hospital data at recruitment, c) three year follow-up data from the families' General Practitioners, and d) linkage to hospital and vaccination databases. Data collection for the five-year follow-up with parents is underway, continuing through 2007. Because there is at present no single national/regional health information system in Ireland, original data instruments were designed to capture data directly from family members and through their hospitals and healthcare providers. A system of relational databases was designed to coordinate data capture for a complex array of study instruments and to facilitate tracking of family members at different time points.

Socio-demographic, lifestyle and cross-generation predictors of self-rated health in mothers during pregnancy.

The Lifeways Cross-generation study was established to assess the influence of socio-economic and familial characteristics on the health status and early development of children. Between October 2001 and June 2002, 1124 women were recruited to the Lifeways study at booking or first visit to maternity hospital. Lifeways mothers were 29.4 (SD 5.9) years old at recruitment, two-thirds from greater Dublin area, 17.9% held a General Medical Services (GMS) card, 64.3% were married and 40.8% were third level educated. At uni-variate level, GMS eligibility, own and parents' education and marital status all predicted mother's self rated health during pregnancy, whilst in the final multivariate logistic regression model, GMS status, household-adjusted income, marital status and grand-maternal education were each independently predictors. The Lifeways cohort confirms the importance of social position in predicting health in pregnant Irish women.

Dietary habits of pregnant women in Ireland.

This analysis of the Lifeways Cohort study mothers during pregnancy (n = 1124), utilises information from a standard food frequency questionnaire completed at baseline recruitment during early pregnancy. We demonstrate that 76% of women achieved recommended intakes of 5 plus portions of fruit and vegetables daily, though this is strongly socially patterned, inversely associated with age and positively associated with level of education. Achievement of the other recommended shelf intakes of the Food Pyramid is much lower, ranging from 12% achieving the recommended sparing intake of foods high in fat, salt or sugar, to 45% consuming the recommended 3 portions per day of meat and poultry. General medical services eligible respondents are generally less likely to achieve recommended intakes. While 61% of women under 25 years old stopped drinking during pregnancy, this dropped to 38% of expectant mothers over 35 years. Less than half (45%) of those (n = 860) who responded specifically to the question reported peri-conceptual folate supplement intake, again strongly socially patterned. These findings both provide important prevalence data and highlight the need for more concerted and supportive health promotion interventions during pregnancy.

Self-reported pre-pregnancy maternal body mass index and infant birth-weight.

This analysis examines the association between maternal characteristics, particularly body mass index (BMI) and infant birth weight in 1048 live infants. Mean reported pre pregnancy BMI of mothers was 23.74 kg/m2 (SD 4.21). The educational level of the mother's parents was independently associated with maternal BMI, those with higher educated parents having a lower reported BMI (F = 2.787, p = 0.029). Mean infant birth weight was 3493 g (SD 18.1) and there was a strong graduated relationship to estimated gestational age. In a sub-group of participating maternal grandmothers (n = 171), reported BMI was 26.7Kg/m2. The BMI of expectant mothers was significantly associated with their own mother's BMI. (r = 0.179, p = 0.005) in this sub-group. These preliminary findings, which will be investigated further with recorded height and weight information, suggest that familial factors are influential, perhaps through genetic predisposition or shared socio-cultural factors such as diet.

The relative influence of socio-demographic, lifestyle, environmental factors and co-morbidity on self rated health of the Irish prisoner population.

A National survey of prisoners' health status was undertaken in 1999/2000 across 13 prisons. Median age of all male prisoners (n = 718) was 25 years. At univariate level, prisoners demonstrated high levels of ill-health, associated with poor self-rated health, including chronic activity limiting illness, GHQ caseness, anxiety and depression. Those with poor self rated health were also of lower educational status, more likely to smoke, or to have taken drugs. In a final multivariate model (n = 512), education level, GHQ caseness, prescribed medication, chronic self limiting illness and reported verbal abuse by prison officers were all independently predictive of poor self rated health. Upstream policy interventions are required to limit the impact of social disadvantage on offending and to maximise proactive health care and rehabilitation during prison stay.

Perceived quality of life and mental health status of Irish female prisoners.

Mental health status and quality of life of female prisoners, the majority of whom are drug-users, was examined as part of a larger, cross-sectional, general healthcare study of the Irish prisoner population. Comparisons were made with drug using and non-drug using male prisoners and females from the general population. Instruments include the GHQ-12 and the WHOQOL-BREF. While their quality of life profile was closer to drug-using male prisoners than other comparison groups, female prisoners still had significantly poorer physical and psychological Quality of Life scores. While poorer quality of life scores may be associated with the more severe drug use patterns of female prisoners it is likely that other factors also contribute. Before resorting to drugs/crime women may have already experienced adversity. There may also be gender differences in response to the combined dimensions of environmental distress. If women are to be imprisoned appropriate comprehensive mental health promotion approaches must address their specific needs.

A national medical education needs' assessment of interns and the development of an intern education and training programme.

A needs' assessment of interns was undertaken using a self-completion questionnaire and a semistructured interview. The questionnaire explored to what degree graduates had been helped to acquire a range of competencies and professional characteristics. In the interviews graduates discussed their self-perceived learning needs, their educational and training experiences and made suggestions. A 25% random sample of 1996 graduate doctors was selected from the five medical schools in Ireland (n=95). The overall response rate was 88% (n=84). The software package SPSS was utilized to carry out descriptive statistics on the questionnaire data while the interview data were analysed qualitatively. Of the responders, 91% reported that they were not prepared for all the skills needed as an intern. History taking and clinical examination were considered well covered at the undergraduate level but little training was received in a range of professional competencies and personal characteristics. Formal education and training during the intern year was found to be poor. However, some skills and characteristics improved during the year as a result of work experience. In the interviews the graduates explored educational issues. They considered an improved clinical experience throughout the undergraduate years to be at the heart of curriculum development but stressed that, in order to succeed, it would have to be accompanied by leadership within the healthcare system and efforts to improve the learning environment.

Bronchopulmonary Kaposi's sarcoma in 106 HIV-1 infected patients.

The objectives of this study were to describe the clinical and radiological features at presentation, and the natural history of HIV-related bronchopulmonary Kaposi's sarcoma. A retrospective review of medical records and chest radiographs was performed in 106 HIV-infected homosexual men with bronchopulmonary Kaposi's sarcoma diagnosed at bronchoscopy between September 1988 and November 1994. The majority of patients had evidence of advanced HIV disease at diagnosis (median CD4 cell count was 15 x 10(6)/l, range 0-288), and 93% had had a diagnosis of cutaneous Kaposi's sarcoma for a median duration of 11 months prior to diagnosis of their bronchopulmonary disease. The most frequent symptoms at presentation were cough (92%), dyspnoea (69%), pleuritic pain (20%), haemoptysis (13%) and wheezing (10%). The most common radiological finding in 73% of our series was of poorly defined and confluent opacities, with predominant middle and lower zone involvement. Median survival was 4 months (range 0-37 months) from diagnosis and 9 months (range 1-25) from the onset of symptoms. Treatment with either chemotherapy or radiotherapy was associated with a significantly reduced risk of death (hazards ratio (HR)=0.48, 95% CI=0.26-0.87). Factors associated with a poor survival, after adjustment for treatment effect were older age (HR=1.79, 95% CI=1.22-2.84) for each 10-year increase in age; a history of pleuritic pain (HR=2.97, 95% CI=1.39-6.32); presence of pleural effusion on X-ray (HR=2.01, 95% CI=1.13-3.59) and a prior diagnosis of cutaneous Kaposi's sarcoma (HR=1.8, 95% CI=1.00, 3.24). Bronchopulmonary Kaposi's sarcoma occurs mainly in patients with advanced HIV disease and a prior history of cutaneous disease. Survival is poor, and adverse prognostic factors include older age at diagnosis and the presence of pleural disease.

Randomized cross-over comparison of liposomal daunorubicin versus observation for early Kaposi's sarcoma.

OBJECTIVES: To evaluate single-agent liposomal daunorubicin chemotherapy in the management of early HIV-related Kaposi's sarcoma (KS). DESIGN: Randomized cross-over comparison of liposomal daunorubicin versus observation. SETTING: Study conducted at single site in tertiary referral HIV unit. PATIENTS: Twenty-nine HIV-seropositive men with < 20 cutaneous KS, no visceral involvement and CD4 cell counts < 400 x 10(6)/I were randomized. Adequate haematological, hepatic and renal function was required for entry. A left ventricular ejection fraction of > 45% was necessary for eligibility. INTERVENTIONS: Patients were randomized to 12 weeks observation or 12 weeks of liposomal daunorubicin 40 mg/m2 every 2 weeks. After 12 weeks, or at disease progression, patients were crossed over to receive the alternative arm. MAIN OUTCOME MEASURES: Disease evaluation was according to AIDS Clinical Trials Group criteria for response assessment and toxicity was recorded using the World Health Organization standardized grading. RESULTS: Response rate to initial liposomal daunorubicin was six out of 15 (40%) and none experienced a spontaneous response during the observation arm. Six patients (40%) randomized to the initial chemotherapy arm progressed during chemotherapy, while 10(72%) in the observation arm progressed. Neutropenia was the main toxicity associated with liposomal daunorubicin and was documented following 20 out of 139(14%) treatment cycles. CONCLUSIONS: Liposomal daunorubicin is a well tolerated and efficacious treatment for early KS; however, the duration of response is brief.

Intrapreneurship: growing a successful hospital diversification strategy.

The recent upheaval in the health care industry has left administrators scrambling after strategies that will ensure their organizations' survival. The author discusses Affiliated Healthcare Systems' successful use of a diversification strategy. Special attention is given to explaining how other organizations might use this system's experience to reduce the risks and increase the rewards inherent in this strategic alternative.