Measuring the principal Hugoniot of inertial-confinement-fusion-relevant TMPTA plastic foams.

Wetted-foam layers are of significant interest for inertial-confinement-fusion capsules, due to the control they provide over the convergence ratio of the implosion and the opportunity this affords to minimize hydrodynamic instability growth. However, the equation of state for fusion-relevant foams are not well characterized, and many simulations rely on modeling such foams as a homogeneous medium with the foam average density. To address this issue, an experiment was performed using the VULCAN Nd:glass laser at the Central Laser Facility. The aim was to measure the principal Hugoniot of TMPTA plastic foams at 260mg/cm^{3}, corresponding to the density of liquid DT-wetted-foam layers, and their "hydrodynamic equivalent" capsules. A VISAR was used to obtain the shock velocity of both the foam and an α-quartz reference layer, while streaked optical pyrometry provided the temperature of the shocked material. The measurements confirm that, for the 20-120 GPa pressure range accessed, this material can indeed be well described using the equation of state of the homogeneous medium at the foam density.

Medical students' unique experience of army leadership training: a qualitative study.

OBJECTIVES: To assess the interactive experience of first year medical students attending the leadership and management course hosted by a British Army Reserve Field Hospital developed in partnership with Liverpool University. METHODS: 244 students submitted a 1000-word structured reflective learning assignment about their reaction to, learning from and any behaviour and attitude changes as a result of, the training. The assignments were thematically analysed to identify how aspects of the training had impacted upon the students' understanding of leadership and teamwork. Their comments relating to the army were analysed to gain insight into their views and experience of the training. RESULTS: Students were surprised at how enjoyable and useful they found the course. Initially they expressed scepticism about what they could learn in an army-based environment. However, the training, particularly command and planning tasks, helped them appreciate and understand the different skills individuals can bring to a team environment, and the importance of everyone contributing. While some students were challenged by aspects of the course, with support and encouragement from team-mates and the army personnel, they learned they could achieve more together. CONCLUSIONS: Teaching leadership and management skills to medical students is a challenge which can be effectively addressed by adapting and developing army training resources. Students overcame initial scepticism about participating, and learned a lot about themselves and each other. In addition, the army developed a better understanding of the doctors of the future. The expertise of the army in delivering this training was crucial to its success as the medical school could not have provided this experience unsupported.

Hyponatremia-associated cognitive impairment in traumatic brain injury.

The case of a traumatic brain injury (TBI) patient with dramatic cognitive deterioration in the absence of medical aetiology other than simultaneous decline in serum sodium led to an investigation of the association between declines in sodium levels and cognitive status. In a population of 50 persons undergoing TBI rehabilitation, 12 (24%) had relative (3 mEq/L) decreases in serum sodium while five (10%) experienced absolute hyponatremia (136 mEq/L). Correlation with cognitive status was significant when the absolute hyponatremia group was compared with those whose sodium levels remained above 136 mEq/L. A case-matched study of the relative hyponatremia group yielded no significant association between sodium-level decreases and cognitive status. These data support previous conclusions indicating wide variation in individual responses to changes in serum sodium. The threshold for significant effects of hyponatremia may be higher in patients with TBI than in populations studied previously.

A simple way to manage menopause.

Menopausal women require early therapy to prevent or ameliorate signs and symptoms as well as pathologic consequences of menopause. Estrogen replacement therapy combined with adequate calcium supplementation and exercise is the only well-established prophylactic regimen. Medroxy-progesterone acetate (Curretab, Cycrin, Provera) is added to the treatment regimen to prevent endometrial hyperplasia in women who have not undergone hysterectomy. When estrogen therapy is medically contraindicated, medroxy-progesterone acetate or salmon calcitonin (Calcimar, Miacalcin) combined with calcium supplementation may be offered. Sodium fluoride (Luride) cannot be recommended for routine use at this time. Considering the lipoprotein effects of various estrogen-delivery systems and the potential side effects of other drugs, much research on the risks and benefits of various therapeutic methods remains to be done.

Laser diode side pumping of neodymium laser rods.

The laser performance of Nd:YAG, Nd:YLF, and Nd:LLGG has been measured using linear laser diode arrays to side pump 3- mm diam laser rods. We obtained 4.4-mJ output at 1064 nm with Nd:YAG from 16-mJ optical pump pulses 200 micros long at 807- and 3- nm FWHM. The overall electrical to optical efficiency was ~ 6%. Over 0.4 mJ at 532 nm was obtained with a KTP intracavity frequency doubler.

Defining the information content of health data systems.

Uses of health information systems depend heavily on the background and experiences of those who evaluate the data. Effective collaboration between physicians and system managers can enhance significantly the decision-making and information obtained from these systems. This article describes some methods of collaboration and the current uses of one system developed through collaborative efforts of physicians and system managers.

The chemotherapy of onchocerciasis X. An assessment of four single dose treatment regimes of MK-933 (ivermectin) in human onchocerciasis.

Nineteen patients from an area of vector control in the savanna region of Northern Ghana, all with moderate to heavy infections with Onchocerca volvulus and some with ocular involvement, were treated with 50, 100, 150 or 200 micrograms kg-1 of ivermectin. Detailed monitoring of clinical and ocular reactions and of alterations in skin microfilarial counts and laboratory indices were carried out during the first 28 days. Microfilarial counts in skin snips and detailed ocular examinations were then repeated at intervals over a period of nine months. Ivermectin slowly eliminated microfilariae from the skin and eye without serious adverse clinical or ocular reactions in all treated groups. There was little difference in efficacy between doses of 100, 150 and 200 micrograms kg-1, and these were more effective than the 50 micrograms kg-1 dose. Very low levels of skin microfilariae were maintained for nine months. Microfilariae were not eliminated from the eye for at least three months. The drug was neither macrofilaricidal nor embryotoxic. However, it produced a dose-dependent stimulation of embryogenesis manifest at one month and succeeded by a suppression of embryogenesis at three months after therapy. In areas where transmission of onchocerciasis has been interrupted, ivermectin may need not be given more often than once a year. The efficacy of the drug on single dosage and the mild adverse reactions produced, if confirmed in subsequent controlled studies, would greatly simplify the treatment of onchocerciasis and would reintroduce new concepts of the role of chemotherapy in the control of onchocerciasis.

Studies of metrifonate in onchocerciasis.

Metrifonate has been studied in the treatment of infections with Onchocerca volvulus in West Africa. In doses of 10 mg/kg daily for six days, metrifonate was effective against the microfilariae but produced unpleasant reactions due both to the death of the microfilariae and to the muscarinic effects of the drug. In a comparison of 10 mg/kg metrifonate, for 3 doses at 10 day intervals, with diethylcarbamazine (D.E.C.) in a total dose of 6.6 g, metrifonate was significantly less effective than D.E.C. in killing microfilariae but produced significantly fewer adverse effects. In a final study comparing metrifonate 10 mg/kg/day given for 3 or for 6 days there was little difference in their therapeutic effect. However, metrifonate 10 mg/kg given for 6 days produced more severe adverse reactions due largely to the muscarinic and nicotinic effects of acetylcholine and these effects were not prevented by the administration of belladonna alkaloids. Metrifonate 10 mg/kg given for 3 doses at 10 day intervals is effective in the treatment of onchocerciasis but is unlikely to replace diethylcarbamazine. Metrifonate has no action on the adult worms.

Differential alcohol use patterns and personality traits among three Alcoholics Anonymous attendance level groups: further considerations of the affiliation profile.

The present study was designed to identify personality and drinking behavior correlates associated with membership in Alcoholics Anonymous (A.A.). Affiliation profiles were developed on the basis of frequency of A.A. attendance; subtypes were defined as non, low, and high affiliates, respectively. An initial canonical correlation analysis assessed the amount of common variance between personality and drinking characteristics. Subsequent discriminant function analyses on the second-order scales of the drinking and personality variables sets identified those variables differentiating the A.A. affiliated groups. High levels of affiliation were associated with a greater degree of anxiety, a tendency to be more affected by feelings rather than intellect, and more deterioration in the physical, exhibited significant differences in perceived benefits, style, and consequences of alcohol usage. The potential therapeutic utility of A.A. affiliation profiles was discussed.

Cardiac response of Nigerian hypertensives to anaesthesia and surgery.

This study was undertaken to determine the cardiac response of Nigerian hypertensives to anaesthesia and surgery, using systolic time intervals as an indication of ventricular function. Nine hypertensive and eight normotensive patients who were admitted for various operations had carotidogram, phonocardiogram and electrocardiogram recorded simultaneously before induction of anaesthesia, after induction and during operation. The pre-ejection phase, (PEP) and the left ventricular ejection time (LVET) were measured from the tracings and the ratio PEP/LVET was calculated. The results showed that for both normotensive patients and hypertensive patients there was a mean increase of the PEP/LVET ratio under anaesthesia and surgery, indicating deterioration of ventricular function. Hypertensive patients showed a much greater deviation from normal, approaching heart failure values. It is concluded that hypertensive patients seemed to be at greater risk during anaesthesia and surgery. The implication is that hypertensive patients should be adequately treated before operation.

Skin tests in Nigerian asthmatics from the equatorial forest zone in Benin, Nigeria.

Forty-two patients with bronchial asthma from the Benin area and 32 control subjects were subjected to skin prick tests for groups of allergens. There was a significant excess of reactions of 5 mm or over to Dermatophagoides farinae amongst the asthmatics. This was the most commonly detected allergen. There was an overall excess in asthmatics of positive reactions of over 5 mm in the other groups although there was no significant excess in any single group. There was no significant difference in the weaker skin reactions (less than 5 mm between) asthmatics and controls. From clinical histories most precipitating factors known to patients were probably non-allergic in origin, exercise, irritant odours, dust and climatic changes being the commonest. Sets of allergens specially prepared for West Africa would be valuable for skin testing asthmatics in this environment.