Observations of Multiple Nuclear Reaction Histories and Fuel-Ion Species Dynamics in Shock-Driven Inertial Confinement Fusion Implosions.

Fuel-ion species dynamics in hydrodynamiclike shock-driven DT^{3}He-filled inertial confinement fusion implosion is quantitatively assessed for the first time using simultaneously measured D^{3}He and DT reaction histories. These reaction histories are measured with the particle x-ray temporal diagnostic, which captures the relative timing between different nuclear burns with unprecedented precision (∼10 ps). The observed 50±10 ps earlier D^{3}He reaction history timing (relative to DT) cannot be explained by average-ion hydrodynamic simulations and is attributed to fuel-ion species separation between the D, T, and ^{3}He ions during shock convergence and rebound. At the onset of the shock burn, inferred ^{3}He/T fuel ratio in the burn region using the measured reaction histories is much higher as compared to the initial gas-filled ratio. As T and ^{3}He have the same mass but different charge, these results indicate that the charge-to-mass ratio plays an important role in driving fuel-ion species separation during strong shock propagation even for these hydrodynamiclike plasmas.

Highly Resolved Measurements of a Developing Strong Collisional Plasma Shock.

The structure of a strong collisional shock front forming in a plasma is directly probed for the first time in laser-driven gas-jet experiments. Thomson scattering of a 526.5 nm probe beam was used to diagnose temperature and ion velocity distribution in a strong shock (M∼11) propagating through a low-density (ρ∼0.01 mg/cc) plasma composed of hydrogen. A forward-streaming population of ions traveling in excess of the shock velocity was observed to heat and slow down on an unmoving, unshocked population of cold protons, until ultimately the populations merge and begin to thermalize. Instabilities are observed during the merging, indicating a uniquely plasma-phase process in shock front formation.

Systematic Fuel Cavity Asymmetries in Directly Driven Inertial Confinement Fusion Implosions.

We present narrow-band self-emission x-ray images from a titanium tracer layer placed at the fuel-shell interface in 60-laser-beam implosion experiments at the OMEGA facility. The images are acquired during deceleration with inferred convergences of ∼9-14. Novel here is that a systematically observed asymmetry of the emission is linked, using full sphere 3D implosion modeling, to performance-limiting low mode asymmetry of the drive.

Ion thermal decoupling and species separation in shock-driven implosions.

Anomalous reduction of the fusion yields by 50% and anomalous scaling of the burn-averaged ion temperatures with the ion-species fraction has been observed for the first time in D^{3}He-filled shock-driven inertial confinement fusion implosions. Two ion kinetic mechanisms are used to explain the anomalous observations: thermal decoupling of the D and ^{3}He populations and diffusive species separation. The observed insensitivity of ion temperature to a varying deuterium fraction is shown to be a signature of ion thermal decoupling in shock-heated plasmas. The burn-averaged deuterium fraction calculated from the experimental data demonstrates a reduction in the average core deuterium density, as predicted by simulations that use a diffusion model. Accounting for each of these effects in simulations reproduces the observed yield trends.

Equation of state measurements of warm dense carbon using laser-driven shock and release technique.

We present a new approach to equation of state experiments that utilizes a laser-driven shock and release technique combined with spatially resolved x-ray Thomson scattering, radiography, velocity interferometry, and optical pyrometry to obtain independent measurements of pressure, density, and temperature for carbon at warm dense matter conditions. The uniqueness of this approach relies on using a laser to create very high initial pressures to enable a very deep release when the shock moves into a low-density pressure standard. This results in material at near normal solid density and temperatures around 10 eV. The spatially resolved Thomson scattering measurements facilitate a temperature determination of the released material by isolating the scattering signal from a specific region in the target. Our results are consistent with quantum molecular dynamics calculations for carbon at these conditions and are compared to several equation of state models.

Exploration of the transition from the hydrodynamiclike to the strongly kinetic regime in shock-driven implosions.

Clear evidence of the transition from hydrodynamiclike to strongly kinetic shock-driven implosions is, for the first time, revealed and quantitatively assessed. Implosions with a range of initial equimolar D3He gas densities show that as the density is decreased, hydrodynamic simulations strongly diverge from and increasingly overpredict the observed nuclear yields, from a factor of ∼2 at 3.1 mg/cm3 to a factor of 100 at 0.14 mg/cm3. (The corresponding Knudsen number, the ratio of ion mean-free path to minimum shell radius, varied from 0.3 to 9; similarly, the ratio of fusion burn duration to ion diffusion time, another figure of merit of kinetic effects, varied from 0.3 to 14.) This result is shown to be unrelated to the effects of hydrodynamic mix. As a first step to garner insight into this transition, a reduced ion kinetic (RIK) model that includes gradient-diffusion and loss-term approximations to several transport processes was implemented within the framework of a one-dimensional radiation-transport code. After empirical calibration, the RIK simulations reproduce the observed yield trends, largely as a result of ion diffusion and the depletion of the reacting tail ions.

Impact of mid-Z gas fill on dynamics and performance of shock-driven implosions at the OMEGA laser.

Shock-driven implosions with 100% deuterium (D_{2}) gas fill compared to implosions with 50:50 nitrogen-deuterium (N_{2}D_{2}) gas fill have been performed at the OMEGA laser facility to test the impact of the added mid-Z fill gas on implosion performance. Ion temperature (T_{ion}) as inferred from the width of measured DD-neutron spectra is seen to be 34%±6% higher for the N_{2}D_{2} implosions than for the D_{2}-only case, while the DD-neutron yield from the D_{2}-only implosion is 7.2±0.5 times higher than from the N_{2}D_{2} gas fill. The T_{ion} enhancement for N_{2}D_{2} is observed in spite of the higher Z, which might be expected to lead to higher radiative loss, and higher shock strength for the D_{2}-only versus N_{2}D_{2} implosions due to lower mass, and is understood in terms of increased shock heating of N compared to D, heat transfer from N to D prior to burn, and limited amount of ion-electron-equilibration-mediated additional radiative loss due to the added higher-Z material. This picture is supported by interspecies equilibration timescales for these implosions, constrained by experimental observables. The one-dimensional (1D) kinetic Vlasov-Fokker-Planck code ifp and the radiation hydrodynamic simulation codes hyades (1D) and xrage [1D, two-dimensional (2D)] are brought to bear to understand the observed yield ratio. Comparing measurements and simulations, the yield loss in the N_{2}D_{2} implosions relative to the pure D_{2}-fill implosion is determined to result from the reduced amount of D_{2} in the fill (fourfold effect on yield) combined with a lower fraction of the D_{2} fuel being hot enough to burn in the N_{2}D_{2} case. The experimental yield and T_{ion} ratio observations are relatively well matched by the kinetic simulations, which suggest interspecies diffusion is responsible for the lower fraction of hot D_{2} in the N_{2}D_{2} relative to the D_{2}-only case. The simulated absolute yields are higher than measured; a comparison of 1D versus 2D xrage simulations suggest that this can be explained by dimensional effects. The hydrodynamic simulations suggest that radiative losses primarily impact the implosion edges, with ion-electron equilibration times being too long in the implosion cores. The observations of increased T_{ion} and limited additional yield loss (on top of the fourfold expected from the difference in D content) for the N_{2}D_{2} versus D_{2}-only fill suggest it is feasible to develop the platform for studying CNO-cycle-relevant nuclear reactions in a plasma environment.

A randomized trial to investigate needle redirections/re-insertions using a handheld ultrasound device versus traditional palpation for spinal anesthesia in obese women undergoing cesarean delivery.

BACKGROUND: Ultrasound may be useful to identify the spinal anesthesia insertion point, particularly when landmarks are not palpable. We tested the hypothesis that the number of needle redirections/re-insertions is lower when using a handheld ultrasound device compared with palpation in obese women undergoing spinal anesthesia for cesarean delivery. METHODS: Study recruits were obese (body mass index (BMI) >30 kg/m2) women with impalpable bony landmarks who were undergoing spinal anesthesia for elective cesarean delivery. Women were randomized to ultrasound or palpation. The primary study outcome was a composite between-group comparison of total number of needle redirections (any withdrawal and re-advancement of the needle and/or introducer within the intervertebral space) or re-insertions (any new skin puncture in the same or different intervertebral space) per patient. Secondary outcomes included insertion site identification time and patient verbal numerical pain score (0-10) for comfort during surgical skin incision. RESULTS: Forty women completed the study. The mean BMI (standard deviation) for the ultrasound group was 39.8 (5.5) kg/m2 and for the palpation group 37.3 (5.2) kg/m2. There was no difference in the composite primary outcome (median (interquartile range) [range]) between the ultrasound group (4 (2-13) [2-22]) and the palpation group (6 (4-10) [1-17]) (P=0.22), with the 95% confidence interval of the difference 2 (-1.7 to 5.7). There were no differences in the secondary outcomes. CONCLUSIONS: Handheld ultrasound did not demonstrate any advantages over traditional palpation techniques for spinal anesthesia in an obese population undergoing cesarean delivery, although the study was underpowered to show a difference.

Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase.

A series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, T_{T}/T_{D}, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.

Double-blind trial of a long-acting bronchodilator preparation ("Nethaprin Dospan") in bronchospastic disease.

A double-blind, placebo-controlled, crossover study was carried out in 48 patients with bronchospastic disease to assess the efficacy of a long-acting bronchodilator preparation ("Nethaprin Dospan") containing etafedrine hydrochloride, bufylline, doxylamine succinate and phenylephrine. Patients received 1 tablet nightly, with an extra dose in the morning if necessary, of active drug or placebo for 1 week, and were then crossed over to the alternative medication for a further week. All patients had marked disability, apparent on initial clinical examination and on respiratory function tests. The results showed that FEV1 and VC were significantly improved with the active medication, and patients slept better, had improved appetite and suppression of cough.

A comparison of an antacid plus antispasmodic combination and aluminium hydroxide in dyspepsia.

A single-blind, between-patient comparative study was carried out in general practice to assess the effectiveness of antacid plus antispasmodic combination tablets (240 mg dried aluminium hydroxide B.P., 144 mg magnesium hydroxide B.P.C., and 5 mg dicyclomine hydrochloride B.P.) and aluminium hydroxide B.P. tablets (500 mg) in the management of chronic dyspepsia. Twenty patients received the combination tablets and 17 the single antacid tablets. They were instructed to chew 2 tablets 3 or 4-times daily and an additional 2 tablets at night if necessary. Patients were assessed initially, and then at 2 and 4 weeks. Both preparations were effective in controlling dyspeptic symptoms. Heartburn and nausea showed an early, significantly greater (p less than 0.05) response to the combined tablet, as did night pain after 4 weeks. Tablet intake of both preparations averaged out at just under 7 tablets per day.

A controlled study of short-term treatment of tension headache.

A double-blind trial was carried out in 12 patients with chronic recurring tension headache to compare the effectiveness of treatment with an analgesic combination ("Syndol") and placebo. Treatment was confined to the period of an attack and the response in the 46 attacks studied showed that, in those of mild to moderate severity, significantly more patients had initial relief within 15 minutes after active treatment than after placebo, and significantly fewer tablets were required to produce complete remission of symptoms for more than 48 hours. The interval between attacks, however, was not significantly affected by active drug or placebo. Severe attacks, which occurred only in the periods assigned to active treatment, required significantly more tablets and a day longer for complete remission.

Comparison of dicyclomine with antacid and without antacid in dyspepsia.

In a study of forty-two patients with dyspepsia, hiatus hernia or duodenal ulcer, dicyclomine (Merbentyl) has been demonstrated to be effective in the control of the symptoms of this disorder. Under double-blind conditions an antacid or placebo supplement was provided and no significant difference in benefit was recorded. The antacid was given in a large tablet and this preparation was more conscientiously taken by patients, and this was equally true for large placebo tablets. Clearly patients like to take frequent treatment for dyspepsia, but symptom control is quite adequate if Merbentyl is given alone.

Flufenamic acid and placebo compared in rheumatoid arthritis and osteoarthritis.

Forty patients in general practice with rheumatoid arthritis or osteoarthritis were identified as suffering from moderate pain and tenderness and moderate stiffness in excess of 30 minutes. After discontinuation of non-steroidal anti-inflammatory drugs for 2 weeks, a crossover study was conducted comparing the benefits of flufenamic acid, 100 mg, four times daily with placebo. At the same time, paracetamol at a dose up to 8 x 500 mg daily, could be used for pain which the patient judged to be unrelieved. Thirty-four patients completed the two 3-week test periods and twenty-one patients were improved in relation to morning stiffness and pain by flufenamic acid and twelve patients by placebo--a difference greater than would have occurred by chance (p = 0.05). At the same time, paracetamol consumption was reduced significantly fron a mean of 91.29 tablets to 60.68 tablets for each 3-week period. Side-effects occurred in ten patients on placebo and fifteen patients on flufenamic acid. One patient on each medication had to discontinue for multiple side-effects. Diarrhoea occurred in two patients on flufenamic acid and in one patient on placebo. Flufenamic acid is clearly effective and side-effects do not occur more often than would be expected by chance when compared with placebo.

Two lozenges containing benzocaine assessed in the relief of sore throat.

A study has been conducted in general practice comparing two brands of lozenges, Merocaine (Merrell) and Tyrozets, (M.S.D.), in the management of acute sore throat and pharyngitis. Eighty-eight patients entered the between-patient study and each completed a diary card covering symptoms experienced and dosage used for each of the two drugs. The doctor reported upon the appearance of the throat and added antibiotics in cases of necessity, which was approximately for one-third of patients. Merocaine proved to be significantly superior to Tyrozets in producing rapid pain relief (within 15 minutes) and reduction of faucial and pharyngeal injection.

A double blind trial of terfenadine and placebo in hay fever using a substitution technique for non-responders.

A double-blind study of terfenadine and placebo in 110 patients suffering from hay fever (confirmed by skin tests) was conducted. A novel technique was applied using an escape envelope containing a reference drug which could be taken under controlled conditions if, after 48 hours, the patient experienced no relief. Significantly more patients on placebo opened the envelope than patients taking the active drug. Terfenadine was demonstrated to be an effective drug in hay fever and produced no more drowsiness than placebo.

[Induction of leukemia in Rauscher virus-resistant mice by mixed infection with M. arthritidis and Rauscher virus]. / Induktsiia leikoza u myshei, rezistentnykh k virusu Raushera, pri smeshannoi infektsii M. arthritidis i virusom Raushera

At 2-10 months after combined infection with Rauscher virus and M. arthritidis of mice (C57BL/6XA/He)F1 resistant to this virus 14 out of 23 animals developed leukemia morphologically identical to Rauscher leukemia induced in sensitive mice. In control groups of similar animals infected with virus alone or mycoplasma alone not a single case of leukemia developed. As a result of serial intraperitoneal passages in syngeneic mice of cells of leukemias primarily induced by mixed mycoplasma-virus infection 3 transplantable leukemia strains were obtained the cytological picture of which was similar with the original. Upon intraperitoneal and subcutaneous inoculations of leukemic cells generalized leukemia develops as well as a local transplant under the skin or in the abdominal wall at the site of needle puncture.

[Morphogenesis of the heart lesion in experimental infection with streptococcal L forms]. / Morfogenez porazheniia serdtsa pri infitsirovanii L-formami streptokokka v éksperimente.

Histological, histochemical, and immunofluorescent methods were used to study alterations in the hearts of 250 randombred white mice inoculated once intraperitoneally with a stable culture of L-forms of beta-hemolytic group A streptococcus in a dose of 2 x 10(6) CFU and sacrificed at intervals of 1 day to 1 year after inoculation. The development of chronic progressive pathological process (inflammatory, dystrophic, and sclerotic) involving all the membranes of the heart and running against an increasing allergic background was demonstrated. In connective tissue formations of the heart, the antigen of streptococcus L-forms could be detected by immunofluorescence throughout the duration of the experiment. The observed pathogenicity of streptococcus L-forms indicates the necessity of elucidating their role in human infectious pathology.