Publications

The detection of polarized continuum and line emission from the nucleus of NGC 4258 by Wilkes et al. (1995) provides an intriguing application of the unified model of Seyfert nuclei to a galaxy in which there is known to be an edge-on, rotating disk of molecular gas surrounding the nucleus. Unlike most Seyfert nuclei, however, NGC 4258 has strongly polarized narrow emission lines. To further investigate the origin of the polarized emission, we have obtained spectropolarimetric observations of the NGC 4258 nucleus at the Keck-II telescope. The narrow-line polarizations range from 1.0% for [S II] 6716 to 13.9% for the [O II] 7319,7331 blend, and the position angle of polarization is oriented nearly parallel to the projected plane of the masing disk. A correlation between critical density and degree of polarization is detected for the forbidden lines, indicating that the polarized emission arises from relatively dense (n_e > 10^4 cm^-3) gas. An archival Hubble Space Telescope narrow-band [O III] image shows that the narrow-line region has a compact, nearly unresolved core, implying a FWHM size of <2.5 pc. We discuss the possibility that the polarized emission might arise from the accretion disk itself and become polarized by scattering within the disk atmosphere. A more likely scenario is an obscuring torus or strongly warped disk surrounding the inner portion of a narrow-line region which is strongly stratified in density. The compact size of the narrow-line region implies that the obscuring structure must be smaller than ~2.5 pc in diameter.

Abstract 1,3‐Butadiene (1,3‐BD) is a high‐value chemical intermediate used mainly as a monomer for the production of synthetic rubbers. The ability to source 1,3‐BD from biomass is of considerable current interest because it offers the potential to reduce the life‐cycle greenhouse gas (GHG) impact associated with 1,3‐BD production from petroleum‐derived naphtha. Herein, we report the development and investigation of a new catalyst and process for the one‐step conversion of ethanol to 1,3‐BD. The catalyst is prepared by the incipient impregnation of magnesium oxide onto a silica support followed by the deposition of Au nanoparticles by deposition–precipitation. The resulting Au/MgO‐SiO 2 catalyst exhibits a high activity and selectivity to 1,3‐BD and low selectivities to diethyl ether, ethylene, and butenes. Detailed characterization of the catalyst shows that the desirable activity and selectivity of Au/MgO‐SiO 2 are a consequence of a critical balance between the acidic–basic sites associated with a magnesium silicate hydrate phase and the redox properties of the Au nanoparticles. A process for the conversion of ethanol to 1,3‐BD, which uses our catalyst, is proposed and analyzed to determine the life‐cycle GHG impact of the production of this product from biomass‐derived ethanol. We show that 1,3‐BD produced by our process can reduce GHG emissions by as much as 155 % relative to the conventional petroleum‐based production of 1,3‐BD.

Acid-degradable microcapsules were prepared via an interfacial polymerization. Degradation of the thin wall of the capsules leads to all-or-nothing cargo release. The only byproducts of degradation are acetone, and a non-toxic triamide. Proof-of-concept experiments showed that cargo can be delivered to and released in cells.

Stellar Explosions Stars that are born with masses greater than eight times that of the Sun end their lives in luminous explosions known as supernovae. Over the past decade, access to improved sky surveys has revealed rare types of supernovae that are much more luminous than any of those that were known before. Gal-Yam (p. 927 ) reviews these superluminous events and groups them into three classes that share common observational and physical characteristics. Gamma-ray bursts are another type of extreme explosive events related to the death of massive stars, which occur once per day somewhere in the universe and produce short-lived bursts of gamma-ray light. Gehrels and Mészáros (p. 932 ) review what has been learned about these events since the launch of NASA's Swift (2004) and Fermi (2008) satellites. The current interpretation is that gamma-ray bursts are related to the formation of black holes. Type Ia supernovae are used as cosmological distance indicators. They are thought to be the result of the thermonuclear explosion of white dwarf stars in binary systems, but the nature of the stellar companion to the white dwarf is still debated. Dilday et al. (p. 942 ) report high-resolution spectroscopy of the supernova PTF 11kx, which was detected on 26 January 2011 by the Palomar Transient Factory survey. The data suggest a red giant star companion whose material got transferred to the white dwarf.

&lt;div&gt;AbstractBackground:&lt;p&gt;Despite evidence that low muscle increases the risk of chemotoxicity, most chemotherapies are dosed on body surface area without considering body composition. Among 178 patients with colon cancer, we assessed muscle and adipose tissue with multiple techniques and examined their associations with relative dose intensity (RDI) and adverse events.&lt;/p&gt;Methods:&lt;p&gt;We estimated (i) cross-sectional skeletal muscle area (SMA) and total adipose tissue (TAT) area at L3 from computed tomography (CT); (ii) appendicular lean mass (ALM) and total body fat (TBF) mass from dual-energy X-ray absorptiometry (DXA); and (iii) total body skeletal muscle mass using D3-creatine (D3Cr) dilution. We standardized each measurement by its sex-specific standard deviation (SD). The primary outcome was reduced RDI (RDI &lt;85%). The secondary outcome was the number of moderate and severe adverse events during each cycle of chemotherapy. We estimated the associations of muscle and adipose tissue measurements (per SD increase) with reduced RDI using logistic regression and adverse events using generalized estimating equations for repeated measures.&lt;/p&gt;Results:&lt;p&gt;Higher CT SMA and DXA ALM were significantly associated with a lower risk of reduced RDI [odds ratios: 0.56 (0.38–0.81) for CT SMA; 0.56 (0.37–0.84) for DXA ALM]. No measurements of muscle or adipose tissue were associated with adverse events.&lt;/p&gt;Conclusions:&lt;p&gt;More muscle was associated with improved chemotherapy completion among patients with colon cancer, whereas muscle and adipose tissue were not associated with adverse events.&lt;/p&gt;Impact:&lt;p&gt;Considering body composition may help personalize dosing for colon cancer chemotherapy by identifying patients at risk for poor chemotherapy outcomes.&lt;/p&gt;&lt;/div&gt;

World models aim to simulate environments and enable effective agent behavior. However, modeling real-world environments presents unique challenges as they dynamically change across both space and, crucially, time. To capture these composed dynamics, we introduce a Spatio-Temporal Road Image Dataset for Exploration (STRIDE) permuting 360-degree panoramic imagery into rich interconnected observation, state and action nodes. Leveraging this structure, we can simultaneously model the relationship between egocentric views, positional coordinates, and movement commands across both space and time. We benchmark this dataset via TARDIS, a transformer-based generative world model that integrates spatial and temporal dynamics through a unified autoregressive framework trained on STRIDE. We demonstrate robust performance across a range of agentic tasks such as controllable photorealistic image synthesis, instruction following, autonomous self-control, and state-of-the-art georeferencing. These results suggest a promising direction towards sophisticated generalist agents--capable of understanding and manipulating the spatial and temporal aspects of their material environments--with enhanced embodied reasoning capabilities. Training code, datasets, and model checkpoints are made available at https://huggingface.co/datasets/Tera-AI/STRIDE.

Recent research has shown that one can use Distributed Hash Tables (DHTs) to build scalable, robust and efficient applications. One question that is often left unanswered is that of simplicity of implementation and deployment. In this paper, we explore a case study of building an application for which ease of deployment dominated the need for high performance. The application we focus on is Place Lab, an end-user positioning system. We evaluate whether it is feasible to use DHTs as an application-independent building block to implement a key component of Place Lab: its "mapping infrastructure." We present Prefix Hash Trees, a data structure used by Place Lab for geographic range queries that is built entire on top of a standard DHT. By strictly layering Place Lab's data structures on top of a generic DHT service, we were able to decouple the deployment and management of Place Lab from that of the underlying DHT. We identify the characteristics of Place Lab that made it amenable for deploying in this layered manner, and comment on its effect on performance.

Abstract Abstract 60 Chronic lymphocytic leukemia (CLL) was formerly considered an accumulative disease of immunologically incompetent lymphocytes that have a slow rate of cell turnover. However, recent studies suggest that CLL cells of some patients may have an unexpectedly high birth rate, which in some subjects, is counterbalanced by a relatively high death rate. In particular, studies on the leukemia cells of patients who ingested heavy water (2H2O) revealed that some patients had leukemia cells that incorporated deuterium into DNA at rates consistent with a birth rate of 1% of the leukemia population per day. This high birth rate, when counterbalanced with comparable rates of leukemia cell turnover, allows patients to maintain a steady state that was suggestive of indolent disease. Preliminary data also suggested a relationship between disease activity and CLL cell birth. To examine the association between measured rates of leukemia-cell turnover with established surrogate markers of aggressive disease, the CLL Research Consortium (CRC) recently completed enrolment of 119 patients with early stage disease. Patients were to be untreated, Rai Stage 0, 1, or 2 and diagnosed within the previous 3 years. The leukemia cells of each of these patients were evaluated by the central tissue core of the CRC for expression of ZAP-70, CD38, and immunoglobulin heavy chain variable region gene (IGHV) mutation status. We report here a subset analysis of baseline data for 59 patients (57% male, age 58.7 ± 10.1 y). Thirty-seven percent of patients (n=22) had leukemic cells that expressed unmutated IGHV, 39% (n=23) had cells that expressed ZAP-70 (&gt; 20% positive by cytoplasmic flow cytometery), and 19% (n=11) had CD38 positive cells (&gt; 30% positive by multiparameter flow cytometry). Associations between the traditional prognostic markers were exceedingly strong (ZAP-70 with mutation status, p &lt; 0.001; ZAP-70 with CD38, p = 0.013; CD38 with mutation status, p =&lt; 0.001). Birth rate was expressed as the peak percent new cells per day calculated from 2H enrichment in DNA using isotope ratio mass spectrometry (IRMS). Data from the previous study suggested more aggressive disease activity associated with a birth rate above 0.35% per day. Birth rates in the present study ranged from 0.07 - 1.31 % per day, spanning both sides of the previously published 0.35% per day cut-off. Using the Wilcoxon rank sum test, patients whose clones expressed unmutated IGHV, were ZAP-70 positive, or were CD38 positive had a significantly higher daily leukemia cell birth rates than subjects who were IGHV mutated (median of 0.39 v 0.24, p = 0.01), ZAP-70 negative (median of 0.36 v. 0.22, p = 0.002), or CD38 negative (0.62 V. 0.24, p = 0.001). Thus, we have shown that CLL cell birth rates can be determined in a multi-centered trial in a large number of patients, and that patients can be stratified into groups with varying rates of perceived cell turnover. The cell turnover data correlate directly in multivariate analysis with established surrogate markers of aggressive disease, a poor clinical course and decreased survival with higher birth rates associating with unmutated IGHV and expression of ZAP-70 and CD38. Clinical follow-up of these patients is underway to determine if these four parameters serve as complementary prognostic markers. Nevertheless, the strong association between established surrogate markers of aggressive disease with high leukemia-cell birth rates suggests that high-rates of leukemia-cell turnover define a biology that is associated with adverse outcome. As such, these studies strengthen the notion that leukemia cell populations that have high rates of cell turnover can more rapidly accumulate secondary and tertiary genetic mutations that potentially govern the progression of this disease. Disclosures: Murphy: KineMed, Inc.: Consultancy, Equity Ownership. Emson:KineMed, Inc.: Employment. Hayes:KineMed, Inc: Consultancy. Holochwost:KineMed, Inc: Employment. Hellerstein:KineMed, Inc.: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding. Chiorazzi:KineMed, Inc: Membership on an entity's Board of Directors or advisory committees.

Despite remarkable progress in the field of MOFs, structures based on long-flexible organic linkers are scarce and the majority of such materials rely on rigid linkers. In this work, crystals of a new metal-organic double ladder (MODL) are obtained by linking a pentapeptide (NH2-Glu-pCO2Phe-pCO2Phe-Ala-Gly-OH) with cadmium acetate to produce a Cd(2-pyrrolidone-pCO2Phe-pCO2Phe-Ala-Gly)(H2O)3 framework. SEM and TEM analyses show the fibrous nature of the crystals and show that the infinite cadmium oxide rod secondary building units (SBUs) are aligned with the longitudinal axis of the nanofibers.

Abstract Patterns of coexpression can reveal networks of functionally related genes and provide deeper understanding of processes requiring multiple gene products. We performed an analysis of coexpression networks for 1,330 genes from the AraCyc database of metabolic pathways in Arabidopsis (Arabidopsis thaliana). We found that genes associated with the same metabolic pathway are, on average, more highly coexpressed than genes from different pathways. Positively coexpressed genes within the same pathway tend to cluster close together in the pathway structure, while negatively correlated genes typically occupy more distant positions. The distribution of coexpression links per gene is highly skewed, with a small but significant number of genes having numerous coexpression partners but most having fewer than 10. Genes with multiple connections (hubs) tend to be single-copy genes, while genes with multiple paralogs are coexpressed with fewer genes, on average, than single-copy genes, suggesting that the network expands through gene duplication, followed by weakening of coexpression links involving duplicate nodes. Using a network-analysis algorithm based on coexpression with multiple pathway members (pathway-level coexpression), we identified and prioritized novel candidate pathway members, regulators, and cross pathway transcriptional control points for over 140 metabolic pathways. To facilitate exploration and analysis of the results, we provide a Web site (http://www.transvar.org/at_coexpress/analysis/web) listing analyzed pathways with links to regression and pathway-level coexpression results. These methods and results will aid in the prioritization of candidates for genetic analysis of metabolism in plants and contribute to the improvement of functional annotation of the Arabidopsis genome.