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Delayed splenic rupture, though uncommon, is a recognised clinical condition and is associated with a significant mortality rate. In the vast majority of cases the patient re-presents with abdominal symptoms and/or signs of acute intraperitoneal haemorrhage. A case is presented of delayed splenic rupture presenting with jaundice attributable to intra-abdominal clot lysis. [ABSTRACT FROM AUTHOR]

We describe the development and demonstration of a high-repetition-rate-capable dual-channel (DC) x-ray spectrometer designed for high-intensity laser-plasma experiments (≥1×1021 W/cm2). The spectrometer, which operates at high repetition rates, is limited only by the refresh rate of targets and the camera's frame rate. It features two channels, each equipped with a flat highly oriented pyrolytic graphite (HOPG) crystal and a unique detector plane, allowing it to resolve two distinct x-ray bands: approximately 7-10 and 10-13 keV. Each detector plate carrier holds two slots for active (scintillators) or passive (imaging plates) x-ray detectors. We present the design and testing of the HR-DC-HOPG using both the COMET laser (10 J, 0.5 ps shot/4 min) at LLNL's Jupiter Laser Facility and the SCARLET laser (10 J, 30 fs shot/min) at Ohio State University. The results demonstrate the spectrometer's performance across various laser energies, target materials, pulse shapes, and detector types., (© 2024 Author(s). Published under an exclusive license by AIP Publishing.)

We present the development of a flexible tape-drive target system to generate and control secondary high-intensity laser-plasma sources. Its adjustable design permits the generation of relativistic MeV particles and x rays at high-intensity (i.e., ≥1 × 1018 W cm-2) laser facilities, at high repetition rates (>1 Hz). The compact and robust structure shows good mechanical stability and a high target placement accuracy (<4 μm RMS). Its compact and flexible design allows for mounting in both the horizontal and vertical planes, which makes it practical for use in cluttered laser-plasma experimental setups. The design permits ∼170° of access on the laser-driver side and 120° of diagnostic access at the rear. A range of adapted apertures have been designed and tested to be easily implemented to the targetry system. The design and performance testing of the tape-drive system in the context of two experiments performed at the COMET laser facility at the Lawrence Livermore National Laboratory and at the Advanced Lasers and Extreme Photonics (ALEPH) facility at Colorado State University are discussed. Experimental data showing that the designed prototype is also able to both generate and focus high-intensity laser-driven protons at high repetition rates are also presented., (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)

The PROBIES diagnostic is a new, highly flexible, imaging and energy spectrometer designed for laser-accelerated protons. The diagnostic can detect low-mode spatial variations in the proton beam profile while resolving multiple energies on a single detector or more. When a radiochromic film stack is employed for "single-shot mode," the energy resolution of the stack can be greatly increased while reducing the need for large numbers of films; for example, a recently deployed version allowed for 180 unique energy measurements spanning ∼3 to 75 MeV with <0.4 MeV resolution using just 20 films vs 180 for a comparable traditional film and filter stack. When utilized with a scintillator, the diagnostic can be run in high-rep-rate (>Hz rate) mode to recover nine proton energy bins. We also demonstrate a deep learning-based method to analyze data from synthetic PROBIES images with greater than 95% accuracy on sub-millisecond timescales and retrained with experimental data to analyze real-world images on sub-millisecond time-scales with comparable accuracy.

We report recent single-shot spatiotemporal measurements of laser pulses, including pulse-front tilt (PFT) and spatial chirp, taken at the Compact Multipulse Terawatt laser at the Jupiter Laser Facility in Livermore, CA. STRIPED FISH, a device that measures the complete 3D electric field of fs to ps laser pulses on a single shot, was adapted to near infrared for these measurements. We present the design of the instrument used for these experiments, the on-shot measurements of systematic high-order PFT, and shot-to-shot variations in the measurements of spatiotemporal couplings. Finally, we simulate the effect of PFT in target normal sheath acceleration experiments. These simulations showed that pulse front tilt can steer hot electrons, shape the distribution of the accelerating sheath field, and increase the variability of cutoff energy in the resulting proton spectra. While these effects may be detrimental to experimental accuracy if the pulse front tilt is left unmeasured, hot electron steering shows promise for precision manipulation of the particle source for a range of applications, including irradiation of secondary targets for opacity measurements, radiography, or neutron generation.

A novel dual-energy fast neutron imaging technique is presented using short-pulse laser-driven neutron sources to leverage their inherent adaptive spectral control to enable 3D volume segmentation and reconstruction. Laser-accelerated ion beams incident onto secondary targets create directional, broadband, MeV-class neutrons. Synthetic radiographs are produced of multi-material objects using ion and neutron spectra derived from analytic and numerical models. It is demonstrated that neutron images generated from small changes to the neutron spectra, controlled by altering the initial laser conditions, are sufficient to isolate materials with differing attenuation coefficients. This is first demonstrated using a simplistic combinatorial isolation method and then by employing more advanced reconstruction algorithms to reduce artifacts and generate a segmentation volume of the constituent materials.

A plasma mirror platform was developed for the OMEGA-EP facility to redirect beams, thus enabling more flexible experimental configurations as well as a platform that can be used in the future to improve laser contrast. The plasma mirror reflected a short pulse focusing beam at 22.5° angle of incidence onto a 12.5 μm thick Cu foil, generating Bremsstrahlung and k α x rays, and accelerating ions and relativistic electrons. By measuring these secondary sources, the plasma mirror key performance metrics of integrated reflectivity and optical quality are inferred. It is shown that for a 5 ± 2 ps, 310 J laser pulse, the plasma mirror integrated reflectivity was 62 ± 13% at an operating fluence of 1670 J cm -2 , and that the resultant short pulse driven particle acceleration and x-ray generation indicate that the on target intensity was 3.1 × 10 18 W cm -2 , which is indicative of a good post-plasma mirror interaction beam optical quality. By deriving the plasma mirror performance metrics from the secondary source scalings, it was simultaneously demonstrated that the plasma mirror is ready for adoption in short pulse particle acceleration and high energy photon generation experiments using the OMEGA-EP system.

We present a deep learning based framework for real-time analysis of a differential filter based x-ray spectrometer that is common on short-pulse laser experiments. The analysis framework was trained with a large repository of synthetic data to retrieve key experimental metrics, such as slope temperature. With traditional analysis methods, these quantities would have to be extracted from data using a time-intensive and manual analysis. This framework was developed for a specific diagnostic, but may be applicable to a wide variety of diagnostics common to laser experiments and thus will be especially crucial to the development of high-repetition rate (HRR) diagnostics for HRR laser systems that are coming online.

X-ray and neutrons are commonly used to image inertial confinement fusion implosions, providing key diagnostic information on the fuel assembly of burning deuterium-tritium (DT) fuel. The x-ray and neutron data provided are complementary as the production of neutrons and x-rays occurs from different physical processes, but typically these two images are collected from different views with no opportunity for co-registration of the two images. Neutrons are produced where the DT fusion fuel is burning; X-rays are produced in regions corresponding to high temperatures. Processes such as mix of ablator material into the hotspot can result in increased x-ray production and decreased neutron production but can only be confidently observed if the two images are collected along the same line of sight and co-registered. To allow direct comparison of x-ray and neutron data, a combined neutron x-ray imaging system has been tested at Omega and installed at the National Ignition Facility to collect an x-ray image along the currently installed neutron imaging line of sight. This system is described, and initial results are presented along with prospects for definitive coregistration of the images.

A Chan-Lam reaction has been used to prepare N-alkenyl-α,β-unsaturated nitrones, which undergo a subsequent thermal rearrangement to the corresponding tri- and tetrasubstituted pyridines. The optimization and scope of these transformations is discussed. Initial mechanistic experiments suggest a reaction pathway involving oxygen transfer followed by cyclization.

Neutron and x-ray imaging provide critical information about the geometry and hydrodynamics of inertial confinement fusion implosions. However, existing diagnostics at Omega and the National Ignition Facility (NIF) cannot produce images in both neutrons and x-rays along the same line of sight. This leads to difficulty comparing these images, which capture different parts of the plasma geometry, for the asymmetric implosions seen in present experiments. Further, even when opposing port neutron and x-ray images are available, they use different detectors and cannot provide positive information about the relative positions of the neutron and x-ray sources. A technique has been demonstrated on implosions at Omega that can capture x-ray images along the same line of sight as the neutron images. The technique is described, and data from a set of experiments are presented, along with a discussion of techniques for coregistration of the various images. It is concluded that the technique is viable and could provide valuable information if implemented on NIF in the near future.

The atmosphere and ionosphere of Venus have been studied in the past by spacecraft with remote sensing or in situ techniques. These early missions, however, have left us with questions about, for example, the atmospheric structure in the transition region from the upper troposphere to the lower mesosphere (50-90 km) and the remarkably variable structure of the ionosphere. Observations become increasingly difficult within and below the global cloud deck (<50 km altitude), where strong absorption greatly limits the available investigative spectrum to a few infrared windows and the radio range. Here we report radio-sounding results from the first Venus Express Radio Science (VeRa) occultation season. We determine the fine structure in temperatures at upper cloud-deck altitudes, detect a distinct day-night temperature difference in the southern middle atmosphere, and track day-to-day changes in Venus' ionosphere.

Although 2-dimensional echocardiography with adjunct intravenous contrast media improves endocardial visualization and enhances quality of spectral Doppler signals, widespread use of contrast agents has not occurred for various reasons. Results from this study indicate that discretionary use of contrast media will enhance endocardial and Doppler signal visualization scores without an impact on total procedure duration, lending credence to an argument for a lower threshold for discretionary use of contrast media.

Background: The aim was to assess the role of plasma Big Endothelin (ET) 1 levels as a marker of disease presence and stage in colorectal adenocarcinoma., Methods: Big ET-1 was measured in the plasma of 37 patients with colorectal cancer. Preoperative systemic plasma levels of Big ET-1 in patients with cancer were compared with levels in 20 age- and sex-matched controls. Portal plasma samples were collected at operation in addition to peripheral venous samples. Immunohistochemical staining for Big ET-1 was performed on a selection of primary tumour specimens and liver metastases., Results: Median (range) preoperative systemic plasma levels of Big ET-1 were significantly higher in patients with cancer than in controls (1.0 (0.3-9.7) versus 0.2 (0.0-6.0) fmol/ml; P = 0.0001). Intraoperative portal plasma levels of Big ET-1 were significantly higher in patients with Dukes' 'D' disease than in patients with Dukes' A, B and C disease (2.1 (1.4-10.0) versus 1.2 (0.3-6.6) fmol/ml; P = 0. 01). Similarly, systemic plasma levels were significantly higher in patients with Dukes' 'D' disease than in those with localized disease (1.9 (1.2-9.7) versus 1.2 (0.2-8.3) fmol/ml; P = 0.01). The presence of microvascular invasion in the tumour specimens was associated with a significantly raised portal plasma level of Big ET-1 (1.6 (1.5-2.1) versus 1.1 (0.8-1.3) fmol/ml; P = 0.04). Immunohistochemistry localized Big ET-1 to the cancer epithelial cells., Conclusion: The plasma level of Big ET-1 is significantly raised in patients with colorectal cancer. Patients with liver metastases have significantly higher levels than those with localized disease.

Objectives: To establish the concentration of isopropanol that exerts the same immediate and sustained effects as n-propanol 60% v/v in surgical scrubbing, and to assess the performance of the test method proposed as the European standard in parallel experiments., Design: Isopropanol at concentrations of 70%, 80%, and 90% v/v was tested in comparison with n-propanol 60%, the proposed reference preparation, in the draft method proposed by the European standard. A Latin square design was used with four balanced blocks of five volunteers each in four experimental runs that were spaced by intervals of 1 week each. Volunteers were allotted randomly to one of the four blocks. Independently, the volunteers' right and left hands also were randomized into two groups for the assessment of either immediate or sustained effects., Setting: Two laboratories supervised by two investigators, one from Vienna, Austria, and one from London, The United Kingdom., Method: The release of skin flora from the fingertips of clean hands was assessed before and after treatment by immediate sampling from one hand and by sampling of the other, gloved hand after 3 hours. The mean log10 reductions (RF) of bacterial release achieved by rubbing the alcoholic preparations for 3 minutes onto the hands were established., Results: For both experiments, the immediate effects of isopropanol 70% (RF, 2.0 and 2.1, respectively) were significantly smaller than those of the reference n-propanol 60% (RF, 2.4 and 2.6, respectively). This also was found with the sustained effects (RF, 0.7 and 1.1 vs 1.0 and 1.6, respectively). At 90%, isopropanol equalled the immediate effect of n-propanol 60%, whereas at 80% it proved slightly (although not significantly) less active. There were no significant differences in the results of both investigators. The sustained effects of isopropanol 80% and 90% were both larger than the reference in Vienna but were found smaller by the London investigator; none of the differences were significant. Mean RFs were significantly different between Vienna and London with n-propanol 60% and isopropanol 70%, but not with isopropanol at 80% or 90%., Conclusions: At 90%, isopropanol is as effective as n-propanol 60%, which was proposed by the European Committee for Standardization as a reference in testing products for surgical hand disinfection. It could, therefore, serve as an alternative if the proposed agent is undesirable for any reason. In parallel experiments by two investigators, the proposed test method proved well workable; the results were very similar and the conclusions identical.

A bistatic radar experiment in 1994, involving reception on Earth of a specularly reflected, linearly polarized 13-centimeter-wavelength signal transmitted from the Magellan spacecraft in orbit around Venus, has established that the surface materials viewed at low and intermediate altitudes on Venus have a relative dielectric permittivity of 4.0 &plusmn; 0.5. However, bistatic results for the Maxwell Montes highlands imply an electrically lossy surface with an imaginary dielectric permittivity of -i 100 &plusmn; 50, probably associated with a specific conductivity of about 13 mhos per meter. Candidates for highlands surface composition include ferroelectrics, a thin frost of elemental tellurium, or a plating of magnetite or pyrites.

The efficacy of sodium hypochlorite was assessed against human immunodeficiency virus type 1 suspended in low (8% v/v) or high (80% v/v) concentrations of serum or in a high (80%) concentration of blood. In the presence of 8% serum, 100 p.p.m. available chlorine in the disinfectant test mixture inactivated 3.75 log TCID50 HIV/ml within 30 s. When the test mixture contained 80% serum, 500 p.p.m. available chlorine inactivated more than 4 log TCID50 HIV/ml in 1-2 min. Lower concentrations of available chlorine were unable to inactivate the virus completely. In the presence of 80% blood, 1000 p.p.m. available chlorine in the disinfectant test mixture was unable to inactivate 3.75 log TCID50 HIV/ml, although 2500 p.p.m. available chlorine was able to inactivate at least 1.5 log TCID50 HIV/ml. In all test mixtures, the chlorine rapidly became combined and thus less active. Our results emphasise the importance of cleaning prior to disinfection with sodium hypochlorite since it may prove to be ineffective in the presence of high levels of organic matter. In cases where prior cleaning is impossible, care must be taken to use the higher recommended concentration (a minimum of 10,000 p.p.m. available chlorine).

In the course of 71 days in lunar orbit, from 19 February to 3 May 1994, the Clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths. These data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side. In addition, laser-ranging measurements provided the first view of the global topographic figure of the moon. The topography of many ancient impact basins has been measured, and a global map of the thickness of the lunar crust has been derived from the topography and gravity.

A common assertion in the literature is that Langhans cells in placental villi decline in number during gestation but this is a misinterpretation which may be caused by the greater growth of villous surface area compared with trophoblast volume. To test this possibility, human placentae were collected at 12-41 weeks of gestation for a cross-sectional study on the packing density of nuclei within villous trophoblast. Numbers of nuclei in the cyto- and syncytiotrophoblast were estimated using a design-based stereological device, the physical disector (parallel pairs of sections). Surface areas were estimated in order to assess the overall growth of villous arborizations. Packing densities of nuclei were calculated and expressed as numbers/1000 microns 2 of villous surface. Densities decreased during gestation and this can be explained by expansion of villous surface area and thinning of trophoblast. The biggest drop in packing density of cytotrophoblast nuclei (30 per cent) occurred between 17-21 and 22-26 weeks and this period coincided with the largest changes in villous surface area (62 per cent increase) and trophoblast thickness (30 per cent decrease). Results are consistent with the notion of an epithelial proliferative unit of constant volume and comprising about nine syncytiotrophoblast nuclei per Langhans cell.

Alcohols are commonly used as disinfectants for skin, surfaces and immersion of some medical instruments. Measurements of the activity of alcohols against human immunodeficiency virus type 1 (HIV-1) must take account of the compatibility of neutralizers used to stop the disinfectant reaction, and of toxicity to the cell line used to detect residual virus. We have developed protocols to measure the efficacy of alcohols against HIV in suspension and dried onto surfaces in the presence of high and low protein concentrations. High titres of HIV in suspension were rapidly inactivated by 70% ethanol, independent of the protein load. When virus was dried onto a glass surface, the rate of inactivation decreased when high levels of protein were present. Due to its rapid evaporation, a spray or a wipe with alcohol cannot be guaranteed to disinfect a surface contaminated with blood or other body fluids without preliminary cleaning.

A cross-sectional sample of human placentae was collected at 12-41 wk, and growth mechanisms within villous subcompartments (trophoblast epithelium, stroma and fetal capillary endothelium) were assessed using state-of-the-art design-based stereological methods. Physical disectors (adjacent pairs of sections) were used to count nuclei in syncytiotrophoblast and in cells of the cytotrophoblast, stroma and endothelium. The volumes of trophoblast and stroma and the surface areas and lengths of capillaries were employed to assess the overall growth of each compartment. Growth within compartments was monitored as total number of nuclei (a measure of nuclear proliferation) and compartment size per nucleus (a measure of hypertrophy). During gestation, all compartments grew dramatically. Numbers of nuclei increased exponentially and followed an uninhibited growth model. Volumetric growth of the placenta did not keep pace with the increase in total nuclear number (all types). Growth of trophoblast was exclusively hyperplastic and proceeded at an average net recruitment rate of 15 million nuclei per hour with a numerical predominance of syncytiotrophoblast nuclei of 9:1. There was no evidence of hypertrophy: trophoblast volume per nucleus averaged 1080 microns 3. Growth within stroma involved cell proliferation (17 million nuclei per hour) and the volume of stroma per nucleus declined at a rate of about 24 microns 3 per week. Capillary growth was hyperplastic (5 million endothelial squames per hour) and, possibly, hypertrophic (the mean area of a squame increased by about 18 microns 2 per week). Linear growth of vessels exceeded cellular recruitment and the density of squames along the capillaries decreased each week by about 5 per mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Procedures used for cleaning/disinfection of fibreoptic bronchoscopes and incidents of mycobacterial contamination were assessed by postal questionnaire. Information supplied by the Infection Control Doctor in 129 of 198 hospitals (65.2%) was used to audit local practice for compliance with national guidelines. Discrepancies between recommended and local practice included lack of specification of detergent/cleaning agent (57%), inadequate contact time for chemical disinfection (40%) and the use of tap water rather than sterile water for rinsing the disinfected bronchoscope (39.7%). Other procedural anomalies associated with mycobacterial contamination included failure to adhere to manufacturers' instructions to dismantle valves prior to cleaning and to autoclave valves/accessories. The association of mycobacterial incidents with the use of automatic washer/disinfectors (17 of 18 incidents) together with Department of Health warnings of build-up of biofilm within these chemical-process machines gives further cause for concern.

Cell-free and cell-associated human immunodeficiency virus cultures suspended in 10% serum remained infectious for several weeks at room temperature. The stability was further increased when cell-associated virus was suspended in neat serum. When dried onto a glass coverslip, virus remained infectious for several days, although cell-associated virus lost infectivity more rapidly than cell-free virus.

A method is presented for obtaining assumption-free estimates of the number of nuclei in the trophoblast of the human placenta and for defining the size of the trophoblast proliferative unit (TPU). The method relies on the disector, a stereological device for counting arbitrary particles in 3-dimensional space using pairs of parallel sections separated by a known distance. It is applied to investigate factors which contribute to trophoblast growth from 13 weeks of gestation to term. Physical disectors were sampled systematically using adjacent 4-4.6 microns thick paraffin sections. Nuclei in the trophoblast (syncytial and cellular) were counted if they appeared in an unbiased counting frame on one section but were absent from the adjacent section. Nuclear packing densities were converted to absolute numbers of nuclei by using placental volume as the reference space. At 37-39 weeks, the average placenta contained 6.4 x 10(10) trophoblast nuclei of which 90 per cent were located within the syncytium and the remainder in the cytotrophoblast. From a knowledge of total trophoblast volume, it was found that each nucleus is associated with 970 microns3 of trophoblast and each cytotrophoblast cell with 11,000 microns3. The latter may be regarded as the volume of a TPU. From 13 weeks of gestation to term, there was a ninefold increase in nuclear number but the trophoblast volumes associated with nuclei, including the size of the TPU, remained constant. Growth of trophoblast is purely hyperplastic and occurs by recruitment of new TPUs.

For the hospital microbiologist, the use of guidelines, policies and standards are an integral part of their professional duties. Both patient-related and laboratory activities involve awareness of specific procedures and the use of equipment or products which have been accepted as appropriate for a particular purpose. The means by which policy is formulated, the guidance available and the standards specified, differ widely from country to country. In the UK, there are few legal requirements or statutory regulations in this area. In consequence, there may be some differences in both the nature and the method of implementation of policies from hospital to hospital. There is increasing concern that legislation and standards produced not only by the UK but also by Europe may impose regulations on infection control and laboratory practice and in particular that such mandatory controls may have adverse effects. These are variously perceived as specifying inappropriate standards, inhibiting clinical freedom and stifling innovation. Such concern is embodied in the question 'are we in control?'.

Magellan probes Venus' surface by 12.6-cm-wavelength vertical and oblique radar scattering and measures microwave thermal emission. Emissivity and root-meansquare slope maps between 330 degrees and 30 degrees E and 90 degrees N and 80 degrees S are dissimilar, although some local features are exceptions. Inferred surface emissivities typically are approximately 0.85, but vary from approximately 0.35 at Maxwell to approximately 0.95 northeast of Gula Mons and other locations. Lowest emissivities appear in topographically high areas; this relation suggests that a phase change or differences in chemical weathering occur at about 6055-kilometer radius. Initial results indicate that there are significant variations in the surface scattering function.

The prolonged use of a hydrogel (polyacrylamide) dressing on circular 1 cm skin defects was tested in a rat experimental model. The rate of healing and changes in bacterial content following inoculation of 1 X 10(8) Staphylococcus aureus, Escherichia coli or Pseudomonas aeruginosa were measured. Wounds inoculated with Staph. aureus or E. coli prior to polyacrylamide occlusion did not have delayed wound contraction and healing and numbers of organisms were falling at 10 days. Wounds inoculated with Ps. aeruginosa showed a delay in healing with a large increase in organisms (greater than 1 X 10(10] after 10 days occlusion. Prolonged wound occlusion by hydrogel dressings may aid in healing by secondary intention but the presence or growth of pseudomonas indicates that frequent changes of dressings should be made.

Babies entering a special care baby unit during a 3-month period were studied prospectively for colonization by gentamicin-sensitive and -resistant coagulase-negative staphylococci (CNS). Gentamicin-resistant isolates were characterized by biotyping, antibiotic sensitivity pattern and phage-typing. All the babies studied became colonized with gentamicin-resistant CNS and often with multiple strains. Gentamicin-sensitive CNS usually appeared first and predominated, but gentamicin-resistant staphylococci could be detected by enrichment culture at a median time of 1 day, and, by direct culture at a median time of 4 days. Similar strains were found in the environment and nasal carriage was detected in 60% of the staff of the unit by enrichment culture. The gentamicin-resistant strains were all resistant to benzylpenicillin and other antibiotics. No particular pathogenic strain could be identified, but clusters of colonizations by distinguishable strains were noted. Biotype SVI was frequently encountered, particularly among clinically significant isolates.

Preliminary reduction of Viking bistatic radar data gives root-mean-square surface slopes in the Hellas basin on Mars of about 4 degrees on horizontal scales averaged over 10 centimeters to 100 meters. This roughness decreases slightly with position along the ground track, south to north. The dielectric constant in this area appears to be approximately 3.1, greater than the martian average. These values are characteristic of lunar maria and are similar to those found near the Viking lander site in Chryse with the use of Earth-based radar.

The Voyager 2 encounter with the Neptune system included radio science investigations of the masses and densities of Neptune and Triton, the low-order gravitational harmonics of Neptune, the vertical structures of the atmospheres and ionospheres of Neptune and Triton, the composition of the atmosphere of Neptune, and characteristics of ring material. Demanding experimental requirements were met successfully, and study of the large store of collected data has begun. The initial search of the data revealed no detectable effects of ring material with optical depth tau [unknown] 0.01. Preliminary representative results include the following: 1.0243 x 10(26) and 2.141 x 10(22) kilograms for the masses of Neptune and Triton; 1640 and 2054 kilograms per cubic meter for their respective densities; 1355 +/- 7 kilometers, provisionally, for the radius of Triton; and J(2) = 3411 +/- 10(x 10(-6)) and J(4) = -26(+12)(-20)(x10(-6)) for Neptune's gravity field (J>(2) and J(4) are harmonic coefficients of the gravity field). The equatorial and polar radii of Neptune are 24,764 +/- 20 and 24,340 +/- 30 kllometers, respectively, at the 10(5)-pascal (1 bar) pressure level. Neptune's atmosphere was probed to a pressure level of about 5 x 10(5) pascals, and effects of a methane cloud region and probable ammonia absorption below the cloud are evident in the data. Results for the mixing ratios of helium and ammonia are still being investigated; the methane abundance below the clouds is at least 1 percent by volume. Derived temperature-pressure profiles to 1.2 x 10(5) pascals and 78 kelvins (K) show a lapse rate corresponding to "frozen" equilibrium of the para- and ortho-hydrogen states. Neptune's ionosphere exhibits an extended topside at a temperature of 950 +/- 160 K if H(+) is the dominant ion, and narrow ionization layers of the type previously seen at the other three giant planets. Triton has a dense ionosphere with a peak electron concentration of 46 x 10(9) per cubic meter at an altitude of 340 kilometers measured during occultation egress. Its topside plasma temperature is about 80 +/- 16 K if N(2)(+) is the principal ion. The tenuous neutral atmosphere of Triton produced distinct signatures in the occultation data; however, the accuracy of the measurements is limited by uncertainties in the frequency of the spacecraft reference oscillator. Preliminary values for the surface pressure of 1.6 +/- 0.3 pascals and an equivalent isothermal temperature of 48 +/- 5 K are suggested, on the assumption that molecular nitrogen dominates the atmosphere. The radio data may be showing the effects of a thermal inversion near the surface; this and other evidence imply that the Triton atmosphere is controlled by vapor-pressure equilibrium with surface ices, at a temperature of 38 K and a methane mixing ratio of about 10(-4).