Pressurized H2 RF cavities in ionizing beams and magnetic fields.

A major technological challenge in building a muon cooling channel is operating rf cavities in multitesla external magnetic fields. We report the first proof-of-principle experiment of a high pressure gas-filled rf cavity for use with intense ionizing beams and strong external magnetic fields. rf power consumption by beam-induced plasma is investigated with hydrogen and deuterium gases with pressures between 20 and 100 atm and peak rf gradients between 5 and 50 MV/m. The low pressure case agrees well with an analytical model based on electron and ion mobilities. Varying concentrations of oxygen gas are investigated to remove free electrons from the cavity and reduce the rf power consumption. Measurements of the electron attachment time to oxygen and rate of ion-ion recombination are also made. Additionally, we demonstrate the operation of the gas-filled rf cavity in a solenoidal field of up to 3 T, finding no major magnetic field dependence. All these results indicate that a high pressure gas-filled cavity is a viable technology for muon ionization cooling.

Nutrition in the community--an exploratory study of oral nutritional supplements in a health board area in Ireland.

BACKGROUND: A review of the General Medical (Payments) Scheme data in the Midland Health Board (MHB) Ireland identified a spend of just over euro 0.5 million on enteral nutritional supplements (oral and tube feeds) in an 11-month period in 1998 [General Medical Services (Payments) Board, 1998, MHB Clinical Nutritional Products: January-December 1998, Dublin]. In 2000, a figure of euro5 million was reported as the annual spend (oral and tube feeds) [General Medical Services (Payments) Board, 2000, MHB Clinical Nutritional Products: January-December 2000, Dublin]. Research has shown that a high proportion of Oral Nutritional Supplements (ONS) are inappropriately prescribed by primary care practitioners (Gall et al., 2001). The role of General Practitioners (GPs) and Public Health Nurses (PHNs) in prescribing ONS to patients aged 65 years and older was examined, as they are directly involved in the delivery of primary health care. AIM: (i) Assess current trends, decision-making processes and monitoring procedures in the use of ONS for older patients in the community. (ii) Identify whether nutritional assessments and appropriate nutritional criteria are standard practice in determining selection of ONS. METHODS: A study was conducted among 99 GPs and 120 PHNs in the MHB. All GPs were selected to participate and 50% (60) of PHNs were randomly selected. A telephone questionnaire was administered to each subject over a 2-week period. RESULTS: Both GPs (78%) and PHNs (47%) reported that their prescription of/recommendations for ONS had increased in the last 4 years. None conducted a full nutritional assessment, but 25% of PHNs used a Nutrition Screening Tool when trying to ascertain whether a patient requires an ONS. Only 19.6% of GPs and 6.8% of PHNs surveyed were aware of the calorie content of a standard 200 mL ONS (sip-feed). In addition, a very significant proportion of both GPs and PHNs do not appear to give appropriate dietary advice to patients who may be at risk of malnutrition. Only 55% of GPs stated that they would specifically review a patient's ONS prescription. All GPs said that they would not conduct a full nutritional assessment at the review appointment. CONCLUSION: The results of this study raise concerns as to the appropriateness of current ONS prescription and monitoring in the community. They also highlight the need for further intervention in the primary care setting in order to ensure that elderly malnourished patients are detected, treated and monitored in an appropriate and cost-effective manner.

Differential metabolic effects on mitochondria by silica hydride using capillary electrophoresis.

Working as an extension of a newly developed method for a capillary electrophoretic analysis of purine nucleotides, nucleosides, bases, and catabolism, an assay of the differential metabolic properties by a novel organosiliceous anionic hydride compound, silica hydride, was evaluated with Chinese hamster ovary mitochondria using a 50-microm poly(acryloylaminopropanol)-coated, fused-silica capillary. The results of this organellar differential analysis indicate a correlation of increased redox pair of NADH to NAD(+) ratios by two times and an increase in ATP levels in the assayed mitochondria by six times. Glucose levels in the organelles were half of the original values. This study validates the electrophoretic method utilizing live organelle fractions for differential metabolic analysis and additionally illustrates some of the emerging novel properties of silica hydride. As confirmation of the results obtained in this assay, additional methods of standard protocol were used to monitor the mitochondrial metabolic activity.

Antioxidant capacity of silica hydride: a combinational photosensitization and fluorescence detection assay.

Utilizing a novel combinational technique incorporating spectrafluorometry and photosensitization, this analysis determined cell viability and cytotoxicity through the introduction of reactive oxygen species and measurement of plasma membrane integrity. Chinese hamster ovary and mouse hybridoma cells were treated with silica hydride after being photosensitized with singlet oxygen, hydroxyl/superoxide, and hydroxyl reactive oxygen species through the use of rose Bengal diacetate, malachite green, and N,N'-bis(2-hydroperoxy-2-methoxyethyl)-1,4,5,8-naphthaldiimide, respectively. The analysis resulted in an easy and effective method for quantifying reactive oxygen species reduction and characterized the radical reduction efficacy of silica hydride at 97% (+/- 0.68%, sigma = 0.84) against singlet oxygen species and over 87% (+/- 0.56%, sigma = 0.70) for the combination of hydroxyl and superoxide reactive species, and 98% (+/- 0.37%, sigma = 0.47) effective for hydroxyl radical species. Nontreated photosensitized controls showed less than 1% viability under the same conditions.

Evaluation of hydroxyl radical-scavenging abilities of silica hydride, an antioxidant compound, by a Fe2+-EDTA-induced 2-hydroxyterephthalate fluorometric analysis.

The hydroxyl radical scavenging capacity and efficacy of a novel organosiliceous anionic hydride compound, silica hydride, were quantified by a recently developed method. The method measures a direct relationship between the hydroxyl radical scavenging capability of the antioxidant compound and the linear decrease in signal from a fluorescent 2-hydroxyterephthalate product created by reacting an Fe(2+)-EDTA complex in the presence of a potential radical scavenger. A fluorescence signal half-inhibition, IC(50), value of 1.4 +/- 0.1 muM was obtained for silica hydride compounds. The validity of the analysis was verified by electron spin resonance spectroscopy, spectrophotometric analysis of NAD(+)/NADH ratios, mitochondrial membrane potential measurements, and assays of both cytochrome c (Fe(3+)) to cytochrome c (Fe(2+)) and epinephrine to adenochrome reductions.

Antioxidant capability and efficacy of Mega-H silica hydride, an antioxidant dietary supplement, by in vitro cellular analysis using photosensitization and fluorescence detection.

Treatment of Chinese hamster ovary and mouse hybridoma cells with Mega-H brand silica hydride, a marketed antioxidant, after photosensitization with singlet oxygen and hydroxyl/superoxide reactive oxygen species through the use of rose bengal diacetate and malachite green resulted in an effective method of reducing free radical activity by more than 96% against singlet oxygen species and more than 86% for hydroxyl and superoxide free radicals with the dosage recommended by the manufacturer. The analysis used a combinational spectrafluorometric technique to determine cell viability and cytotoxicity through the mechanism of intracellular esterase activity and plasma membrane integrity. Photosensitized controls not treated with silica hydride showed less than 1% viability under the same conditions. The reduction of the introduced free radicals and singlet oxygen species and the consequent high levels of cell viability may be the result of effective and efficient antioxidant and radical scavenging properties of silica hydride.

Refractive outcome following radial keratotomy and combined radial and astigmatic keratotomy.

PURPOSE: To determine whether the visual and refractive outcomes of combined astigmatic and radial keratotomy (AK/RK) procedures was different from that following RK for the correction of naturally occurring compound myopic astigmatism and spherical myopia. SETTING: Private professional practice, San Diego, California, USA. METHODS: The computer database of all incisional procedures performed by one surgeon over 10 years was reviewed to compare the visual acuity outcome of AK/RK and RK procedures. Enhancement procedures were excluded. Only data from the last office visits were analyzed to establish the relationship between visual acuity and type of keratotomy procedure performed. A multiple regression model was constructed, which included covariates of age, postoperative keratometric cylinder, and postoperative refraction. RESULTS: After controlling for covariates, the AK/RK population had significantly lower postoperative uncorrected visual acuity levels than the RK population (P < .03) after one operation (prior to enhancement surgery). CONCLUSIONS: Using the nomograms for myopia correction for unenhanced RK cases, combined AK and RK procedures appeared to reduce the expected visual results. Surgeons may consider modifying surgical nomograms to account for the expected spherical undercorrection that can occur when myopia and astigmatism are corrected simultaneously.

Human erythrocyte choline uptake in uraemia: the role of intracellular substrate and an investigation into the effects of haemodialysis.

1. Erythrocyte choline transport was studied in 10 haemodialysis patients immediately before and after a haemodialysis session and in 10 control subjects. Choline uptake was measured in erythrocytes from normal and uraemic patients after washing in vitro and subsequent incubation in autologous plasma. Amines present in uraemic plasma were examined for their effect on choline transport in normal erythrocytes. 2. NMR spectroscopy was used to measure choline, trimethylamine and dimethylamine in erythrocyte extracts from nine control subjects, 32 subjects with renal impairment and nine samples from haemodialysis patients. 3. The increased choline influx in uraemic erythrocytes is significantly decreased by prior haemodialysis (mean Vmax pre-dialysis 146 +/- 20 mumol h-1 l-1, post-dialysis 113 +/- 13 mumol h-1 l-1 (P < 0.005). After in vitro washing there is a fall in Vmax, and no longer any significant difference between pre- and post-dialysis samples. There remains a significant difference in the erythrocyte choline Vmax between samples from patients with chronic renal failure and from normal subjects (P < 0.005). 4. Human plasma was found to contain factors capable of increasing choline uptake. Trimethylamine and dimethylamine were found to inhibit choline uptake. Trimethylamine and trimethylamine-N-oxide trans-stimulated choline efflux, but the major transport substrate present in erythrocyte extracts from all groups was choline, which was higher in those with renal impairment (71 +/- 10 mumol/l) than in haemodialysis patients (47 +/- 10 mumol/l) and control subjects with normal renal function (40 +/- 9 mumol/l). 5. Our data suggest that erythrocyte choline transport is increased in uraemia as a consequence of increased transporter number or activity, rather than the presence of intracellular substrate.

Effect of incision direction on refractive outcome after radial keratotomy.

PURPOSE: To determine whether the direction of radial keratotomy (RK) incisions (centripetal versus centrifugal) affects refractive outcome. SETTING: Private ophthalmology office. METHODS: The database of a single surgeon was retrospectively reviewed. Stepwise regression was used to select significant predictors of refraction change in the population. In addition to incision direction, variables evaluated were optic zone diameter, number of incisions, patient age, corneal curvature, and planned incision depth. RESULTS: All variables except planned incision depth and corneal power affected refractive outcome. After controlling for number of incisions, optic zone diameter, and patient age, centripetal incisions decreased myopia 0.87 diopters more than centrifugal incisions. CONCLUSIONS: Our results, consistent with previous investigations, found that number of incisions, optic zone diameter, and patient age were significant predictors of refractive outcome after RK. Incision direction was also a significant predictor by itself or coupled with optic zone diameter and number of incisions, with the centripetal incision decreasing myopia more.

Effect of incision direction on refractive outcome after radial keratotomy.

PURPOSE: Radial keratotomy incisions can be made centripetally or centrifugally. The benefits and effects of both techniques have been disputed since American surgeons began performing RK in the late 1970s. We examined the RK databases of a single surgeon to determine if incision direction was associated with refractive outcome. METHODS: Stepwise regression was employed to select the important predictors of refraction change in the population. In addition to incision direction, variables eligible for entry into the model were optic clear zone diameter, incision number, patient age, corneal curvature and planned incision depth. RESULTS: All variables except for planned incision depth and corneal power entered the model. CONCLUSIONS: The results were consistent with previous investigations that found incision number, optic clear zone diameter and patient age important predictors of outcome. We also found incision direction to be a significant predictive variable with centripetal incisions decreasing myopia 0.6 diopters more than centrifugal incisions.

A case of craniomandibular dermatodysostosis associated with focal glomerulosclerosis.

This paper reports an isolated case of the exceedingly rare cutaneo-skeletal condition craniomandibular dermatodysostosis, in which focal glomerular sclerosis and end-stage renal failure developed and renal transplantation was required.

A microcomputer measuring system applied to real-time ultrasound video imaging.

The high-resolution graphics facility of a microcomputer has been synchronized with real-time ultrasound images on a television monitor, allowing quick and accurate measurements of linear distances, are lengths, perimeter lengths, and areas, whether regular or irregular in shape. No particular knowledge of computers is required, as the program gives step-by-step directions. However, the full facilities of a 48K microcomputer using BASIC language remain accessible, which is a considerable advantage over equivalent measuring systems currently available.