Surface changes observed on a Venusian volcano during the Magellan mission

Venus has a geologically young surface, but it is unknown whether it has ongoing active volcanism. From 1990 to 1992, the Magellan spacecraft imaged the planet's surface, using synthetic aperture radar. We examined volcanic areas on Venus that were imaged two or three times by Magellan and identified an ~2.2-square-kilometer volcanic vent that changed shape in the 8-month interval between two radar images. Additional volcanic flows downhill from the vent are visible in the second-epoch images, although we cannot rule out that they were present but invisible in the first epoch because of differences in imaging geometry. We interpret these results as evidence of ongoing volcanic activity on Venus.

Analytical Models for Multipath and Switch Leakage for the SWOT Interferometer

The Ka-Band Radar Interferometer (KaRIn) instrument on the Surface Water and Ocean Topography (SWOT) mission is a single-pass synthetic aperture radar (SAR) interferometer tasked with, among others, measuring ocean topography to within a few centimeters over kilometer scale resolutions. A SAR interferometer relies on very precise phase difference measurements between two spatially distant antennas to estimate topography. Multipath phase caused by unintended scattering off the spacecraft structure is a known error source for radar interferometers and takes up a significant portion of the KaRIn error budget. This paper outlines some analytical multipath models that were used for instrument design, performance analysis and mitigation of the multipath signal.

Abstract IA07: Impact of immunotherapy on COVID-19 immunity: Insights from checkpoint blockade in cancer

Over the last few years, we have gained insights into how immunotherapy, including checkpoint blockade, modulates key CD4 and CD8 T cell subsets in anti-tumor immunity. This information can now give us insights into how immunotherapy can impact immunity in the setting of COVID-19. Indeed, we recently demonstrated that cancer patients with T cell depletion have high COVID-19 mortality despite adequate B cell and antibody production, highlighting the importance of cellular immunity. Conversely, in the setting of B cell depletion by anti-CD20 therapy, CD8 T cells can compensate for impaired humoral immunity. PD-1 blockade increases the activation and proliferation of CD4 T follicular-helper cells, which plays a key role in promoting B cell responses and quality antibody production. Thus, it is possible that PD-1 blockade enhances the efficacy of SARS-CoV-2 vaccination. However, PD-1 blockade in melanoma patients was actually associated with at 2-fold decrease in SARS-CoV-2 specific antibodies and neutralizing antibodies, compared to a healthy donor cohort. PD-1 blockade was also associated with depletion of memory CD4 T cells, suggesting there may be consequences to prolonged PD-1 blockade.

Citation Format: Paulina Coutifaris, Kevin Wang, Sokratis Apostolidis, Mark Painter, Ahron Flowers, Rishi Goel, Divij Mathew, Ajinkya Pattekar, Ravi Amaravadi, Tara Mitchell, Paul Bates, Scott Hensley, Giorgos Karakousis, Lynn Schuchter, Allie Greenplate, E. John Wherry, Alexander C. Huang. Impact of immunotherapy on COVID-19 immunity: Insights from checkpoint blockade in cancer [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr IA07.

Naïve T cells surpass pre-existing memory to dominate post-vaccine responses in humans

Background

There is a critical unmet need for vaccines against emerging diseases and common infections, such as HIV, malaria, and tuberculosis. Defining the mechanisms by which memory T cell responses are generated in humans is essential for developing efficacious vaccines. We have previously described that human adults possess pre-existing memory phenotype CD4+ T cells specific for viral antigens to which they have never been expose. The goal of our study is to test how memory precursors respond to antigen challenge and to identify other key aspects of the human precursor repertoire that are required for a robust vaccine response.

Methods

We are using yellow fever virus (YFV) vaccination as a model to examine the link between precursor T cell composition and cellular response to cognate antigen stimulation. We screened study participants for HLA allele of interest and the absence of prior exposure to YFV by serology. We then use peptide-MHC tetramers to identify YFV-specific T cells before vaccination and at multiple time points after YFV vaccination.

Results

Direct ex vivo analyses of YFV-specific CD4+ T cells in the blood revealed three key observations. First, precursor T cells vary in size, but a larger precursor frequency does not predict better post-vaccination response. Second, naïve precursors outcompete memory precursors to generate a larger effector population. Third, the magnitude of effector cell frequency predicts clonotypic selection into the stable memory pool.

Conclusions

Durable memory response to primary immune challenge is dependent on successful preservation of naïve T cell repertoire. Age-associated erosion of naïve T cell pool may contribute to the decreased effectiveness of vaccines in older individuals.

Validation of Glacier Topographic Acquisitions from an Airborne Single-Pass Interferometer

The airborne glacier and ice surface topography interferometer (GLISTIN-A) is a single-pass radar interferometer developed for accurate high-resolution swath mapping of dynamic ice surfaces. We present the first validation results of the operational sensor, collected in 2013 over glaciers in Alaska and followed by more exhaustive collections from Greenland in 2016 and 2017. In Alaska, overlapping flight-tracks were mosaicked to mitigate potential residual trends across-track and the resultant maps are validated with lidar. Furthermore, repeat acquisitions of Columbia Glacier collected with a three day separation indicate excellent stability and repeatability. Commencing 2016, GLISTIN-A has circumnavigated Greenland for 4 consecutive years. Due to flight hour limitations, overlapping swaths were not flown. In 2016, comparison with airborne lidar data finds that residual systematic errors exhibit evenly distributed small slopes (all less than 10 millidegrees) and nadir biases were typically less than 1 m. Similarly 2017 data exhibited up to meter-scale nadir biases and evenly distributed residual slopes with a standard deviation of ~10 millidegrees). All satisfied the science accuracy requirements of the Greenland campaigns (3 m accuracy across an 8 km swath).

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake

Tectonic motion across the Los Angeles region is distributed across an intricate network of strike-slip and thrust faults that will be released in destructive earthquakes similar to or larger than the 1933 M6.4 Long Beach and 1994 M6.7 Northridge events. Here we show that Los Angeles regional thrust, strike-slip, and oblique faults are connected and move concurrently with measurable surface deformation, even in moderate magnitude earthquakes, as part of a fault system that accommodates north-south shortening and westerly tectonic escape of northern Los Angeles. The 28 March 2014 M5.1 La Habra earthquake occurred on a northeast striking, northwest dipping left-lateral oblique thrust fault northeast of Los Angeles. We present crustal deformation observation spanning the earthquake showing that concurrent deformation occurred on several structures in the shallow crust. The seismic moment of the earthquake is 82% of the total geodetic moment released. Slip within the unconsolidated upper sedimentary layer may reflect shallow release of accumulated strain on still-locked deeper structures. A future M6.1-6.3 earthquake would account for the accumulated strain. Such an event could occur on any one or several of these faults, which may not have been identified by geologic surface mapping.

Enhanced protection for influenza vaccines using a novel rOv-ASP-1 adjuvant aqueous formulation (VAC2P.933)

Adjuvants have been used to enhance the efficacy of a variety of vaccines; however, no adjuvant is included in current influenza vaccines used in the United States. In this study, we found that a novel adjuvant, rOv-ASP-1, co-administrated with inactivated influenza vaccine using an aqueous formulation, substantially improved the influenza-specific antibody response and protection against lethal infection in a mouse model. rOv-ASP-1 enhanced the magnitude of the specific antibody response after immunization with low doses of influenza vaccine, allowing antigen-sparring by 10-fold. The rOv-ASP-1 formulated vaccine induced a more rapid response and a stronger Th1-associated antibody response compared to vaccine alone and to the vaccine formulated with the adjuvant alum. Importantly, rOv-ASP-1 significantly enhanced cross-reactive antibody responses and protection when challenged with a heterologous influenza virus strain. These results demonstrate that rOv-ASP-1 is an effective adjuvant that: 1) accelerates and enhances the specific antibody response induced by influenza vaccine; 2) allows for antigen sparing; and 3) augments a Th1-biased and cross-reactive antibody response that confers heterologous protection.

Clinical pathology of Greyhounds and other sighthounds

Owing to the development of Greyhounds as racing sighthounds, these dogs have acquired unique physiologic adaptations that distinguish them from other breeds. Reference intervals for many analytes in retired racing Greyhounds (RRGs) differ from those of other breeds; most of the hematologic differences have also been described in other sighthounds. In this review, we provide a survey of the literature on clinical pathology of Greyhounds and other sighthounds and results of laboratory testing, including analysis of CBCs, biochemical profiles, coagulation tests, and blood gases, in RRGs at The Ohio State University. Major clinicopathologic differences in this breed include higher RBC mass, creatinine concentration, glomerular filtration rate, activities of hepatic enzymes, and concentration of cardiac troponin, as well as lower WBC, neutrophil, and platelet counts, thromboelastographic values, and concentrations of serum haptoglobin, total globulins, and T4.

A comprehensive archaeological map of the world's largest preindustrial settlement complex at Angkor, Cambodia

The great medieval settlement of Angkor in Cambodia [9th-16th centuries Common Era (CE)] has for many years been understood as a "hydraulic city," an urban complex defined, sustained, and ultimately overwhelmed by a complex water management network. Since the 1980s that view has been disputed, but the debate has remained unresolved because of insufficient data on the landscape beyond the great temples: the broader context of the monumental remains was only partially understood and had not been adequately mapped. Since the 1990s, French, Australian, and Cambodian teams have sought to address this empirical deficit through archaeological mapping projects by using traditional methods such as ground survey in conjunction with advanced radar remote-sensing applications in partnership with the National Aeronautics and Space Administration (NASA)/Jet Propulsion Laboratory (JPL). Here we present a major outcome of that research: a comprehensive archaeological map of greater Angkor, covering nearly 3,000 km2, prepared by the Greater Angkor Project (GAP). The map reveals a vast, low-density settlement landscape integrated by an elaborate water management network covering>1,000 km2, the most extensive urban complex of the preindustrial world. It is now clear that anthropogenic changes to the landscape were both extensive and substantial enough to have created grave challenges to the long-term viability of the settlement.

The lakes of Titan

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

Titan Radar Mapper observations from Cassini's T3 fly-by

Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.

The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes

The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.

Cassini Radar Views the Surface of Titan

The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.

Amplitude-based height-reconstruction techniques for synthetic aperture ladar systems

We examine the performance of amplitude-based height-estimation techniques for use with airborne synthetic aperture ladar (SAL) sensors in generating three-dimensional reconstructions of ground targets. Such techniques lend themselves to implementation more readily than phase-based techniques and are also more tolerant to phase instabilities that might be associated with SAL systems. For pairwise amplitude-comparison monopulse processing, we present analyses of the expected height sensitivity and bias of SAL systems in terms of the system parameters. We verify this analysis with simulations, and we also provide an overview of other SAL phenomena that affect height-estimation accuracy. We then propose an array-based joint-processing approach that can be applied instead of pairwise monopulse processing. We show that the joint-processing approach represents the maximum-likelihood estimator for obtaining the target height, and we demonstrate that the proposed approach significantly reduces bias-induced errors.

Takingabigrisk.com. Execs chuck high-powered hospital jobs for e-venture

Impatient with the industry's slow transition to quality improvement, an unusual group of former healthcare executives--including a canine deputy--is trying to establish a high-powered Internet venture from bargain-basement digs. The entrepreneurs, with visions of an IPO dancing in their heads, want to give providers and patients access to the information they need to improve health outcomes.

Leaders of the PACS in radiology. Clinical imaging technology helps hospitals enhance accuracy, savings, service

The image of radiology is changing rapidly. Hospitals are chucking the old light boxes and plugging in high-performance, filmless clinical image networks that not only enhance the accuracy of diagnoses but also cut long-term costs and improve service to referring physicians.