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We stabilize a chosen radio frequency beat note between two optical fields derived from the same mode-locked laser pulse train in order to coherently manipulate quantum information. This scheme does not require access or active stabilization of the laser repetition rate. We implement and characterize this external lock, in the context of two-photon stimulated Raman transitions between the hyperfine ground states of trapped Yb^+171 quantum bits.

Energy-dispersive powder diffraction (EDPD) has now been in routine use for over thirty years. During that time it has been applied to a wide range of academic and industrial problems. The advent of image plate and charged coupled device (CCD) area detectors has enabled the use of monochromatic radiation for many of the applications traditionally reserved for EDPD. Here the basic principles and major applications of EDPD are reviewed, the impact of image plate and CCD detectors is assessed and the possible future roles for EDPD is explored.

The equipment and methodology for in situ study of hydrothermal reactions using synchrotron radiation are described. This equipment is currently used at the Synchrotron Radiation Source, Daresbury Laboratory, UK, at temperatures up to about 230°C. To demonstrate the utility of this approach three experiments are described: crystallization of Fe- and Cr- doped tobermorite starting compositions to produce mixed tobermorite/xonotlite end products; crystallization of gyrolite and pectolite from a starting gel of gyrolite composition reacted with NaOH solution; and formation of the hydrogarnet, katoite, from a mixture of portlandite, amorphous alumina and amorphous silica. Kinetic analyses using the Ammi equation are reported for each system and used to calculate rate constants and deduce reaction mechanisms. Higher synchrotron X-ray energies (up to 200 keV) would allow thicker walled pressure vessels to be used, with a consequent increase in temperature to supercritical conditions, perhaps to above 400° C.

BACKGROUND : Few therapies are currently available to treat keratosis pilaris atrophicans (KPA), a spectrum of disorders which includes ulerythema ophryogenes and atrophoderma vermiculata. OBJECTIVE : To evaluate the response of KPA to treatment with the pulsed dye laser (PDL) with regard to improvements in erythema and skin roughness, treatment tolerability, and side effects. METHODS : Treatment of all facial areas involved with KPA with the PDL at 585 nm was evaluated in 12 patients. Prior to and after each treatment skin erythema was estimated using an erythema meter, and skin roughness was analysed using micrometer evaluation of a skin surface biopsy taken from the same mapped area and anaysed by computer to calculate the roughness profile. RESULTS : Patients received 2 to 8 treatments with the PDL with energies ranging from 6.0 to 7.5 J/cm 2 . Clinical improvement was noted in all patients with significant reduction in erythema scores. Pre-treatment scores ranged from 4 to 13 (mean 8.3) and post-treatment 0 to 8 (mean 3.1) ( P < 0.05). Improvements in skin roughness were clinically apparent in all but two patients, but these were not significant on evaluation of skin surface biopsies. Treatment was generally well tolerated, and side effects other than local pain during treatment were very few. CONCLUSION : PDL treatment appears to be a safe and effective treatment for the erythema associated with KPA but does not give significant improvement in associated skin roughness.

A complementary pair of rapid methods for the energy calibration of solid‐state detectors have been developed. Each method requires only a single measurement from either (i) a glass sample containing elements chosen to produce fluorescence lines over a suitable energy range when exposed to a polychromatic beam of X‐rays, or (ii) a powder diffraction standard in the presence of diffraction slits. The fluorescent glass method has the advantage of allowing simultaneous energy calibration of a number of detectors without requiring diffraction slits. There is the potential for the glass material to be incorporated into virtually any sample holder to allow a continuous in situcalibration. Complementary observations of a powder diffraction standard allow simultaneous calibration of diffraction 2θ and monitoring of the detector for drift.

The decomposition reaction of kaolinite has been investigated as a function of the defectivity of the starting material and the temperature of reaction. Time resolved energy-dispersive powder diffraction patterns have been measured using synchrotron radiation, both under a constant heating rate (heating rates from 10 to 100° C/min) and in isothermal conditions (in the temperature range 500 to 700° C). The apparent activation energy of the dehydroxylation process is different for kaolinites exhibiting a different degree of stacking fault density. The results of the analysis of the kinetic data indicate that the starting reaction mechanism is controlled by diffusion in the kaolinite particle. The diffusion process is dependent on the defective nature of both kaolinite and metakaolinite. At high temperatures, and at higher heating rates, the reaction mechanism changes and the resistance in the boundary layer outside the crystallites becomes the rate-limiting factor, and nucleation begins within the reacting particle. During the final stage of the dehydroxylation process the reaction is limited by heat or mass transfer, and this might be interpreted by the limited diffusion between the unreacted kaolinite domains and the metakaolinite matrix.

The present work is a follow-up of the investigation on the decomposition reaction of kaolinite as a function of the defectivity of the starting material and the temperature of reaction. In the present work we study the high temperature reaction of mullite synthesis from kaolinite, from the starting point of the results obtained in the first part.

Accidental hypothermia and heatstroke are more common in aged populations. While peripheral factors are undoubtedly important to the high incidence of dysthermia in the aged, alterations in central temperature controls associated with aging may be primarily responsible. It has been shown that the sensitivity of the hypothalamus to neurotransmitters is changed in aged animals, and it may be that similar alterations in central temperature controls underlie the increased susceptibility to dysthermia. As a first step in testing this hypothesis the responsiveness of central temperature controls of aged squirrel monkeys to taurine, a putative inhibitory neurotransmitter or neuromodulator, was tested. Intracerebroventricular (i.c.v.) administration of this sulfonated amino acid (0.5-4.0 mg) produced dose-related hypothermia in squirrel monkeys over nine years of age in a thermoneutral environment (23°C). Younger animals had significantly smaller hypothermias. In a hot environment (30°C) there were no significant differences between the temperature decreases of the two age groups after any dose. However, in a cold environment (17°C), in which young animals developed slightly larger hypothermias than in the thermoneutral environment, core temperature of the aged squirrel monkeys dropped so rapidly in response to even the lowest dose that they had to be removed and warmed to prevent death by hypothermia. The temperature controls of the aged squirrel monkey appear to be extrememly sensitive to taurine. The findings indicate that a rise in central taurine concentration in old primates can, in a cold environment, produce an effect very much like accidental hypothermia in aged man.

Several RNA virus inhibitors were evaluated against simian (SA11) rotavirus infections in vitro and murine rotavirus gastroenteritis in vivo. Test compounds included 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin), 3-deazaguanine (3-DG), 3-deazauridine, and 9-(S)-(2,3-dihydroxypropyl)adenine [(S)-DHPA]. All drugs inhibited total infectious SA11 virus yields in MA-104 cells. Ribavirin, 3-DG, and (S)-DHPA affected [3H]uridine uptake into uninfected MA-104 cells in both the acid-soluble and -insoluble fractions. All drugs reduced the levels of dense (precursor) and light (complete) SA11 particle yields compared with control but did not alter the relative amounts of dense compared with light particles, suggesting that the agents did not interfere with virus assembly. Ribavirin and 3-DG inhibited SA11 polypeptide synthesis, as determined by polyacrylamide gel electrophoresis studies. None of the agents or mono- and triphosphate derivatives of ribavirin inhibited SA11 RNA polymerase activity. In murine rotavirus studies, oral therapy with ribavirin-2',3',5'-triacetate and (S)-DHPA increased mean survival time, but no increase in survivor rate was observed. 3-DG- and (S)-DHPA-treated mice had a more rapid weight gain than controls, suggesting a probable lessening of the severity of the disease.

The involvement of light (L) and dense (D) bovine rotavirus particle types during virus replication has been studied. It was found that infectious parental L virions are uncoated in vivo to a particle similar to native D particles. Differences in the rate of synthesis and relative yields of L and D particles in MDBK and MA-104 cells have been detected. Results from pulse-chase labeling experiments indicate that D particles serve as morphogenic precursors to the complete L virion.

The infectivity of most rotaviruses is enhanced by treatment with trypsin. We studied the mechanism of enhancement of examining the effect of trypsin on rotavirus infectivity, aggregation, early interactions with host cells, and structure. The results indicated that trypsin does not increase levels of infectious virus by dispersion of aggregates or affect the efficiency or rate of attachment of virus to cells. A fraction of virus that was not infections without trypsin treatment was found to attach to cells, but did not initiate antigen synthesis. When cells were infected with labeled, purified virus, increased levels of uncoated particles were found in cells infected with trypsin-treated virus. Infection of cells with trypsin-treated virus also led to greater levels of RNA synthesis early in the infection. The results suggest that trypsin converts a noninfectious fraction of virus into infectious virus by allowing this fraction to uncoat in the infected cell. Trypsin was found to cleave an 88,000-dalton structural polypeptide of bovine rotavirus generating 67,000- and 20,000-dalton cleavage products.

We outline the need to study the early hydration of cements by dynamic diffraction methods, and demonstrate how this can be done using a "hydration cell" designed specifically for the parallel beam geometry of synchrotron energy-dispersive diffraction. The method has been applied to three systems: a model component of portland cement, a high-alumina cement and an ettringite-based cement. The results show how this technique might be used to gather information on the kinetics of the chemical processes involved. In the case of ettringite, we can follow dynamically the crystallisation process on an unprecedented 20 second time scale.

Two detector systems are currently being developed for use with high pressure cells on beamline 9 at Daresbury Laboratory. The first is a television area x-ray camera which is used for rapid alignment and specimen characterisation. The second is an imaging plate system which is being developed to obtain accurate integrated intensities from small volume powder samples.The television detector has been used to determine lattice parameters to an accuracy of 1 × 10-3 Å. The measured intensities compare well with data from the same specimen collected on film.The imaging plate system was used in the same configuration as the television detector and the film. The specimens studied were La2CuO4 and InSb. The early results from this detector show a great deal of promise especially in the low photon flux region which is essential for determining accurate intensities from weak Debye-Scherrer rings. A radial integration program for summing over the whole diffraction range is being developed.

Energy dispersive X-ray diffraction (EDXRD) techniques are applied to study the development of crystalline phases during the synthesis of microporous materials. We present data for both zeolite A and AlPO-5 systems. We explore the effects of template concentration and of temperature. The measured activation energy for zeolite A of ~58 kJ mol^-1 accords well with that observed for other silicate systems. The kinetics revealed by our study accord with the nucleation/growth model of the Avrami−Erofeev treatment.

Titers of bovine rotavirus in excess of 10(9) immunofluorescent infectious units per ml of culture fluids have been produced, using trypsin treatment of the virus. Infectivity of preparations of the virus can be increased with as little as 1 ng of trypsin per ml, with maximum increases of 1 to 2 log10 with 1 microgram of trypsin per ml. The virus grows to titers in excess of 10(5) immunofluorescent units per ml in MDBK, LLC-MK2, MA-104, and HeLa cells. When MDBK cells are infected with a multiplicity of infection of 20, maximum yields of cell-associated, trypsin-enhanceable virus are obtained 4 to 8 h postinfection. Maximum yields of cell-free, trypsin-enhanceable virus are produced 16 to 20 h postinfection. The results presented here indicate that trypsin can be used to produce high-titer stocks of bovine rotavirus.

Real-time in situ energy-dispersive X-ray diffraction has been used to study the synthesis of the open-framework sulfide TMA−SnS-1, under hydrothermal conditions. The effects of varying the temperature of reaction, reactant source, and pH of solution on the synthesis have been studied. It is found that temperature is the primary factor in determining whether crystalline products are formed, while the pH of solution and reactant source were found to be important in determining the rate of reaction and the polytypic structure produced. Evidence has been obtained that in cases where crystalline TMA−SnS-1 is formed, the reaction proceeds via an intermediate disordered lamellar phase, before reacting further to form the final product.

The effects of four ribonucleic acid virus inhibitors were evaluated in cell cultures and in mice to determine inhibitory effects against bluetongue virus and Colorado tick fever virus (CTFV). Test compounds included 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin), 3-deazaguanine, 3-deazauridine, and 9-(S)-(2,3-dihydroxypropyl)adenine. Ribavirin-2',3',5'-triacetate (ribavirin triacetate) was evaluated in vivo against CTFV. Inhibition of cytopathic effect and plaque reduction were used to evaluate antiviral activity. In cytopathic effect inhibition studies, bluetongue virus was markedly inhibited by 3-deazaguanine and 3-deazauridine in Vero cells with moderate inhibition by the other agents. Ribavirin and 3-deazaguanine markedly inhibited CTFV in MA-104 cells, 3-deazauridine was slightly less active, and 9-(S)-(2,3-dihydroxypropyl)adenine was negative. Ribavirin was less effective in Vero cells against CTFV. When mice were inoculated intracerebrally with CTFV and treated by a single intracerebral injection with drug, ribavirin triacetate increased the number of survivors, 3-deazaguanine increased mean survival time, and ribavirin was negative. Intraperitoneal treatment of infected mice with ribavirin triacetate for 1 week significantly increased the number of survivors and mean survival time, providing strong evidence that the agent is active across the blood-brain barrier.

Radium being comparatively a new agent, it is premature to take the position that it has yet reached its maturity or possibilities. As all innovations do, it is now running the critical gamut. In one camp it is unconditionally condemned, while in the other it is equally acclaimed. Where such contention exists the truth is found in the midway position.Though radium is yet in its developmental period, and though already we have abandoned some of our earlier fondest hopes, still, in the past five years, there have been deduced certain well established clinical facts.Menstruation is a complex process influenced by innumerable factors, ranging from undeveloped organs, defective endocrines and new growths down to constitutional dyscrasias. In many instances its derangement is a local expression of a constitutional condition; therefore it is most difficult correctly to divide cases of uterine bleeding, of these types, into segregated pathologic groups. In

Although it has been known for centuries that cancer is peculiarly susceptible to heat, its application was not established on an intelligent basis until Percy, in 1912, experimentally proved that cancer cells would be destroyed when exposed to a temperature of 113 F. for twenty minutes, and, further, that the normal tissue would live in a temperature as high as 131.9 F.With this as a fundamental principle, he worked out a scheme by which heat could be applied to cervical carcinoma on a far more elaborate scale than had ever heretofore been possible. Up to this time we had been trying to realize the same brilliant results accomplished by Byrne of Brooklyn, but he left no definite technical plan to follow. Each worker groped along independent lines. There was no definite knowledge of the physical effect of heat on cancer cells, and consequently individual efforts ended in gross disappointment.

LARRMACC, that is, the Local Authority Radiation and Radioactivity Monitoring Advice and Collation Centre Ltd, held their National Conference entitled `Safeguarding Our Future: Meeting Public Concern Over Nuclear Waste' at the Swallow Hotel in Liverpool on 5 November 1998. A wide variety of speakers were involved from all sides of the nuclear debate, and the Conference provided a valuable insight into the way Local Government organisations respond to matters involving radioactive material.