Biomedical subjects
Publications and source records attributed to J A Ball.
Adult vaccination saves lives and is cost-effective. During influenza epidemics, more than 20,000 estimated deaths occur in the United States. Despite the benefits of adult vaccination and the availability of usage guidelines, vaccination rates remain low. In 1999, only 67% and 55% of elderly persons reported receiving influenza and pneumoccal vaccines. Vaccination indications are categorized as age, health, occupation, lifestyle, and environment.
The material properties of greatest importance in microwave processing of a dielectric are the complex relative permittivity epsilon = epsilon'-jepsilon", and the loss tangent, tan delta = epsilon"/epsilon'. This paper describes two convenient laboratory based methods to obtain epsilon', epsilon" and hence tan delta of fibre-reinforced thermoplastic (FRTP) composites. One method employs a microwave network analyzer in conjunction with a waveguide transmission technique, chosen because it provides the widest possible frequency range with high accuracy. The values of the dielectric constant and dielectric loss of glass fibre reinforced (33%) low density polyethylene, LDPE/GF (33%), polystyrene, PS/GF (33%), and Nylon 66/GF (33%), were obtained. Results are compared with those obtained by another method using a high-temperature dielectric probe.
OBJECTIVE: Started in late 1994, the Vaccines for Children (VFC) program is a major entitlement program that provides states with free vaccines for disadvantaged children. Some evaluation studies have been conducted, but they do not include individually matched pre-post comparisons of physician responses. This project studied the effect of the VFC on the physician likelihood of referring children to public vaccine clinics for immunizations. DESIGN: In 1999, trained personnel conducted a survey of a cohort of physicians who previously participated in surveys on barriers to childhood vaccination conducted before VFC implementation. Responses were matched, and pre- versus post-VFC comparisons were made. SETTING AND PARTICIPANTS: Minnesota and Pennsylvania primary care physicians selected by stratified random sampling and initially studied in 1990 to 1991 and 1993, respectively. MAIN OUTCOME MEASURES: Likelihood of referral of a child to a public vaccine clinic. RESULTS: On a scale of 0 to 10, physician likelihood of referring an uninsured child decreased by a mean of 1.9 (95% confidence interval: 1.2-2.5) from pre- to post-VFC. Two fifths (45%) of physicians reported that the VFC decreased the number of referrals from their practice to public vaccine clinics and 50% gave intermediate responses. Among physicians who participate in VFC, only 9% were likely to refer a Medicaid-insured child in contrast to 44% of those not participating. CONCLUSIONS: Physicians' reported referral and likelihood of referring Medicaid-insured and uninsured children has decreased because of VFC in Minnesota and Pennsylvania.vaccination/economics, vaccination/legislation and jurisprudence, immunization programs/economics, immunization programs/utilization, vaccines/economics, Medicaid/economics, national health programs United States, child health services.
OBJECTIVE: Immunization rates for influenza and pneumococcal vaccines among the elderly (especially minority elderly) are below desired levels. We sought to answer 4 questions: (1) What factors explain most missed immunizations? (2) How are patient beliefs and practices regarding adult immunization affected by racial or cultural factors? (3) How are immunizations and patient beliefs affected by physician, organizational, and operational factors? and (4) Based on the relationships identified, can typologies be created that foster the tailoring of interventions to improve immunization rates? STUDY DESIGN: A multidisciplinary team chose the PRECEDE-PROCEED framework, the Awareness-to-Adherence model of clinician response to guidelines, and the Triandis model of consumer decision making as the best models to assess barriers to and facilitators of immunization. Our data collection methods included focus groups, face-to-face and telephone interviews, self-administered surveys, site visits, participant observation, and medical record review. POPULATION: To encounter a broad spectrum of patients, facilities, systems, and interventions, we sampled from 4 strata: inner-city neighborhood health centers, clinics in Veterans Administration facilities, rural practices in a network, and urban/suburban practices in a network. In stage 1, a stratified random cluster sample of 60 primary care clinicians was selected, 15 in each of the strata. In stage 2, a random sample of 15 patients was selected from each clinician's list of patients, aiming for 900 total interviews. CONCLUSIONS: This multicomponent approach is well suited to identifying barriers to and facilitators of adult immunizations among a variety of populations, including the disadvantaged.
In this paper we present the development of a DNA analysis system using a microfabricated channel device and a novel transmission imaging spectrograph which can be efficiently incorporated into a high throughput genomics facility for both sizing and sequencing of DNA fragments. The device contains 48 channels etched on a glass substrate. The channels are sealed with a flat glass plate which also provides a series of apertures for sample loading and contact with buffer reservoirs. Samples can be easily loaded in volumes up to 640 nL without band broadening because of an efficient electrokinetic stacking at the electrophoresis channel entrance. The system uses a dual laser excitation source and a highly sensitive charge-coupled device (CCD) detector allowing for simultaneous detection of many fluorescent dyes. The sieving matrices for the separation of single-stranded DNA fragments are polymerized in situ in denaturing buffer systems. Examples of separation of single-stranded DNA fragments up to 500 bases in length are shown, including accurate sizing of GeneCalling fragments, and sequencing samples prepared with a reduced amount of dye terminators. An increase in sample throughput has been achieved by color multiplexing.
OBJECTIVE: Concerns about financial barriers to vaccination led to the creation of the Vaccines for Children (VFC) program, which provides free vaccines to states for disadvantaged children. Our objective was to understand the effect of free vaccine and insurance on pediatric nurse practitioners' (PNPs) likelihood of referring children to public vaccine clinics. Although referral from the medical home to public vaccine clinics is preferable to not vaccinating, there are disadvantages, including the potential for windows of inadequate protection and fragmentation of care. METHODS: A standardized survey was conducted by trained personnel using computer-assisted telephone interviewing. We interviewed a national random sample of primary care PNPs in 1997. RESULTS: In 1997, 252 of 271 (93%) directly contacted PNPs were interviewed. The percentage of respondents receiving free vaccines was 82%. Among PNPs not receiving free vaccines, the percentages stating that they were likely to refer insured, Medicaid insured, and uninsured children to public vaccine clinics were 7%, 27%, and 67%, respectively. In contrast, among PNPs receiving free vaccines, only 46% would refer an uninsured child and 10% a Medicaid child. CONCLUSIONS: Most respondents received free vaccine supplies in 1997. Based on current PNP data and previous physician data, most clinicians who do not receive free vaccine supplies are likely to refer uninsured children to public vaccine clinics. In contrast, clinicians who receive free vaccine supplies are much more likely to vaccinate uninsured and Medicaid-insured children.
The small aperture coupling theory of the broad wall to broad wall (Moreno) coupler is reviewed and extended. It is shown that a lower limit on the directivity is given by the ratio of magnetic polarizability to electric polarizability for the coupling apertures. Hence directivity may be improved by using very narrow crossed slots for coupling. The results of coupling measurements on a Moreno coupler are presented to demonstrate the accuracy of the small aperture theory. A small aperture design procedure has also been developed for the narrow wall to broad wall coupler, which takes into account the effect of wall proximity on slot coupling. The measured results for the manufactured coupler are in excellent agreement with this theory.
Weber-Christian disease is an inflammatory disorder of fatty tissue which usually presents with raised red tender nodules in the skin. Although there may be additional systemic upset, there are very few reports of neurological features associated with this condition. We report a patient with biopsy-confirmed systemic Weber-Christian disease in whom a transient partial myelopathy, of probable inflammatory origin, was the most prominent feature. Based on recent reports of the effects of immune mediators on neuronal function, a possible pathogenetic explanation for this syndrome is suggested.
The aqueous vanadyl ion ([VO(H(2)O)(5)](2+)) has been investigated by X-band EPR, 94 GHz W-band EPR, and ESE-ENDOR. These experiments reveal information about the hyperfine (|A(xx)| = 208.5 MHz, |A(yy)| = 208.5 MHz, |A(zz)| = 547.0 MHz), and nuclear quadrupole coupling (|e(2)qQ| = 5.6 MHz) of the (51)V nucleus. The measured nuclear quadrupole coupling parameters are compared to values determined by density functional theory calculations (|e(2)qQ| = 5.2 MHz). These theoretical calculations illustrate that axial ligands and molecular distortions can alter the magnitude of the nuclear quadrupole interaction.
The wide range of applications of microwave technology in manufacturing industries has been well documented (NRC, 1994; Thuery, 1992). In this paper, a new way of joining fibre reinforced thermoplastic composites with or without primers is presented. The microwave facility used is also discussed. The effect of power input and cycle time on the heat affected zone (HAZ) is detailed together with the underlying principles of test piece material interactions with the electromagnetic field. The process of autogenous joining of 33% by weight of random glass fibre reinforced Nylon 66, polystyrene (PS) and low density polyethylene (LDPE) as well as 23.3% by weight of carbon fibre reinforced PS thermoplastic composites is discussed together with developments using filler materials, or primers in the heterogenous joining mode. The weldability dependence on the dielectric loss tangent of these materials at elevated temperatures is also described.
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Goodpasture's syndrome, or antiglomerular basement membrane disease, is a disorder in which lungs and kidneys are affected by the binding of anti-GBM antibodies, leading to pulmonary hemorrhage and glomerulonephritis with rapidly progressive renal insufficiency. Recent advances in the understanding of disease pathogenesis and diagnosis and treatment have significantly improved our ability to recognize the syndrome, distinguish it from other similar disorders, and offer successful treatment. This article focuses on the pathogenetic features, clinical manifestations, diagnostic strategies, and therapeutic principles of anti-GBM disease.
OBJECTIVE: Gastric (GU) and duodenal ulcers (DU) are common adverse effects of nonsteroidal anti-inflammatory drugs (NSAID). Endoscopically diagnosed upper gastrointestinal (GI) ulceration occurs in about 24% of longterm NSAID users. Coadministration of misoprostol with the NSAID reduces the incidence of NSAID induced GU and DU and their complications. However, compliance is limited by the different dosing regimens of misoprostol and NSAID and GI symptoms associated with misoprostol at its recommended q.i.d. dose. We compared the efficacy, safety, and incidence of endoscopic upper GI ulceration associated with the administration of 2 combinations of diclofenac (50 or 75 mg) and misoprostol 200 microg (D50/M200 t.i.d., D75/M200 b.i.d.), diclofenac 75 mg b.i.d., and placebo in a 6 week, randomized, double blind study in patients with osteoarthritis (OA) of the knee or hip. METHODS: A total of 572 patients with symptomatic OA of the knee or hip and history of GU, DU. or 10 or more erosions were randomized to receive D50/M200 t.i.d., D75/M200 b.i.d., diclofenac 75 mg b.i.d., or placebo for 6 weeks. Arthritis assessments were performed at baseline, 2, and 6 weeks, and upper GI endoscopies at baseline and end of treatment. RESULTS: All active treatment groups were significantly better than placebo, at all visits, in improving OA symptoms. There were no significant differences in arthritis efficacy between the diclofenac/ misoprostol combinations and diclofenac. However, endoscopically diagnosed GU and/or DU were significantly less frequent in patients receiving D50/M200 t.i.d. (8%), D75/M200 b.i.d. (7%), and placebo (4%) compared to diclofenac 75 mg b.i.d. (17%). Adverse events were not different between the active treatment groups, except for higher incidences of flatulence with D75/M200 and diarrhea with D50/M200. CONCLUSION: Diclofenac 50 mg/misoprostol 200 microg t.i.d. and diclofenac 75 mg/misoprostol 200 microg b.i.d. are as efficacious as diclofenac 75 mg b.i.d. in the treatment of OA, but are associated with a significantly lower incidence of gastric and/or duodenal ulcers.
Electron spin echo electron-nuclear double resonance (ESE-ENDOR) experiments performed on a broad radical electron paramagnetic resonance (EPR) signal observed in photosystem II particles depleted of Ca2+ indicate that this signal arises from the redox-active tyrosine YZ. The tyrosine EPR signal width is increased relative to that observed in a manganese-depleted preparation due to a magnetic interaction between the photosystem II manganese cluster and the tyrosine radical. The manganese cluster is located asymmetrically with respect to the symmetry-related tyrosines YZ and YD. The distance between the YZ tyrosine and the manganese cluster is estimated to be approximately 4.5 A. Due to this close proximity of the Mn cluster and the redox-active tyrosine YZ, we propose that this tyrosine abstracts protons from substrate water bound to the Mn cluster.
We describe a patient with a paraneoplastic brain-stem encephalitis due to an occult small cell carcinoma of the lung. He developed episodes of central sleep apnoea culminating in acute respiratory failure. Antibodies resembling anti-Hu antibodies were demonstrated in both serum and cerebrospinal fluid.
Basilar artery thrombosis (BATS) is a progressive disorder which may present with fluctuating neurological signs of varying degrees of severity. Unless the diagnosis is considered, the confused young patient may be thought to be under the influence of drugs or to be psychologically ill, and indeed the Munchausen syndrome may be considered. The more elderly patient may be diagnosed simply as having had a cerebrovascular accident. This paper presents the cases of three patients admitted through the accident and emergency (A&E) department of St Mary's Hospital, London with basilar artery thrombosis during a 6-month period. All these patients demonstrated the classic triad for this syndrome of: (1) long tract neurological signs, (2) impaired conscious level, and (3) complex ocular signs. The concern is that, for patients with more subtle signs, a diagnosis of BATS may not be considered, and a neurological opinion may be thus delayed and no treatment with anticoagulants or thrombolytic agents would be given. Two of the three patients were treated with anticoagulants and improved, while in the third patients anticoagulation was judged inappropriate and the patients died from progression of the disease with respiratory complications.