Efficient Large-scale Approximate Nearest Neighbor Search on the GPU

We present a new approach for efficient approximate nearest neighbor (ANN) search in high dimensional spaces, extending the idea of Product Quantization. We propose a two-level product and vector quantization tree that reduces the number of vector comparisons required during tree traversal. Our approach also includes a novel highly parallelizable re-ranking method for candidate vectors by efficiently reusing already computed intermediate values. Due to its small memory footprint during traversal, the method lends itself to an efficient, parallel GPU implementation. This Product Quantization Tree (PQT) approach significantly outperforms recent state of the art methods for high dimensional nearest neighbor queries on standard reference datasets. Ours is the first work that demonstrates GPU performance superior to CPU performance on high dimensional, large scale ANN problems in time-critical real-world applications, like loop-closing in videos

Microwave and submillimeter wave scattering of oriented ice particles

Microwave (1-300GHz) dual-polarization measurements above 100GHz are so far sparse, but they consistently show polarized scattering signals of ice clouds. Existing scattering databases of realistically shaped ice crystals for microwaves and submillimeter waves (> 300GHz) typically assume total random orientation, which cannot explain the polarized signals. Conceptual models show that the polarization signals are caused by oriented ice particles. Only a few works that consider oriented ice crystals exist, but they are limited to microwaves only. Assuming azimuthally randomly oriented ice particles with a fixed but arbitrary tilt angle, we produced scattering data for two particle habits (51 hexagonal plates and 18 plate aggregates), 35 frequencies between 1 and 864GHz, and 3 temperatures (190, 230 and 270K). In general, the scattering data of azimuthally randomly oriented particles depend on the incidence angle and two scattering angles, in contrast to total random orientation, which depends on a single angle. The additional tilt angle further increases the complexity. The simulations are based on the discrete dipole approximation in combination with a self-developed orientation averaging approach. The scattering data are publicly available from Zenodo (https://doi.org/10.5281/zenodo.3463003). This effort is also an essential part of preparing for the upcoming Ice Cloud Imager (ICI) that will perform polarized observations at 243 and 664GHz. Using our scattering data radiative transfer simulations with two liquid hydrometeor species and four frozen hydrometeor species of polarized Global Precipitation Measurement (GPM) Microwave Imager (GMI) observations at 166GHz were conducted. The simulations recreate the observed polarization patterns. For slightly fluttering snow and ice particles, the simulations show polarization differences up to 11K using plate aggregates for snow, hexagonal plates for cloud ice and totally randomly oriented particles for the remaining species. Simulations using strongly fluttering hexagonal plates for snow and ice show similar polarization signals. Orientation, shape and the hydrometeor composition affect the polarization. Ignoring orientation can cause a negative bias for vertically polarized observations and a positive bias for horizontally polarized observations

Long-Lived, Strongly Emissive, and Highly Reducing Excited States in Mo(0) Complexes with Chelating Isocyanides

Newly discovered tris(diisocyanide)molybdenum(0) complexes are Earth-abundant isoelectronic analogues of the well-known class of [Ru(α-diimine)3]2+ compounds with long-lived 3MLCT (metal-to-ligand charge transfer) excited states that lead to rich photophysics and photochemistry. Depending on ligand design, luminescence quantum yields up to 0.20 and microsecond excited state lifetimes are achieved in solution at room temperature, both significantly better than those for [Ru(2,2′-bipyridine)3]2+. The excited Mo(0) complexes can induce chemical reactions that are thermodynamically too demanding for common precious metal-based photosensitizers, including the widely employed fac-[Ir(2-phenylpyridine)3] complex, as demonstrated on a series of light-driven aryl–aryl coupling reactions. The most robust Mo(0) complex exhibits stable photoluminescence and remains photoactive after continuous irradiation exceeding 2 months. Our comprehensive optical spectroscopic and photochemical study shows that Mo(0) complexes with diisocyanide chelate ligands constitute a new family of luminophores and photosensitizers, which is complementary to precious metal-based 4d6 and 5d6 complexes and represents an alternative to nonemissive Fe(II) compounds. This is relevant in the greater context of sustainable photophysics and photochemistry, as well as for possible applications in lighting, sensing, and catalysis

Human TPX2 is required for targeting Aurora-A kinase to the spindle

Aurora-A is a serine-threonine kinase implicated in the assembly and maintenance of the mitotic spindle. Here we show that human Aurora-A binds to TPX2, a prominent component of the spindle apparatus. TPX2 was identified by mass spectrometry as a major protein coimmunoprecipitating specifically with Aurora-A from mitotic HeLa cell extracts. Conversely, Aurora-A could be detected in TPX2 immunoprecipitates. This indicates that subpopulations of these two proteins undergo complex formation in vivo. Binding studies demonstrated that the NH2 terminus of TPX2 can directly interact with the COOH-terminal catalytic domain of Aurora-A. Although kinase activity was not required for this interaction, TPX2 was readily phosphorylated by Aurora-A. Upon siRNA-mediated elimination of TPX2 from cells, the association of Aurora-A with the spindle microtubules was abolished, although its association with spindle poles was unaffected. Conversely, depletion of Aurora-A by siRNA had no detectable influence on the localization of TPX2. We propose that human TPX2 is required for targeting Aurora-A kinase to the spindle apparatus. In turn, Aurora-A might regulate the function of TPX2 during spindle assembly

Hemolytic Activity of pH-Responsive Polymer-Streptavidin Bioconjugates

Drug delivery systems that increase the rate and/or quantity of drug release to the cytoplasm are needed to enhance cytosolic delivery and to circumvent nonproductive cell trafficking routes. We have previously demonstrated that poly(2-ethylacrylic acid) (PEAAc) has pH-dependent hemolytic properties, and more recently, we have found that poly(2-propylacrylic acid) (PPAAc) displays even greater pH-responsive hemolytic activity than PEAAc at the acidic pHs of the early endosome. Thus, these polymers could potentially serve as endosomal releasing agents in immunotoxin therapies. In this paper, we have investigated whether the pH-dependent membrane disruptive activity of PPAAc is retained after binding to a protein. We did this by measuring the hemolytic activity of PPAAc−streptavidin model complexes with different protein to polymer stoichiometries. Biotin was conjugated to amine-terminated PPAAc, which was subsequently bound to streptavidin by biotin complexation. The ability of these samples to disrupt red blood cell membranes was investigated for a range of polymer concentrations, a range of pH values, and two polymer-to-streptavidin ratios of 3:1 and 1:1. The results demonstrate that (a) the PPAAc−streptavidin complex retains the ability to lyse the RBC lipid bilayers at low pHs, such as those existing in endosomes, and (b) the hemolytic ability of the PPAAc−streptavidin complex is similar to that of the free PPAAc

Erosion, Geological History, and Indigenous Agriculture: A Tale of Two Valleys

Irrigated pondfields and rainfed field systems represented alternative pathways of agricultural intensification that were unevenly distributed across the Hawaiian Archipelago prior to European contact, with pondfields on wetter soils and older islands and rainfed systems on fertile, moderate-rainfall upland sites on younger islands. The spatial separation of these systems is thought to have contributed to the dynamics of social and political organization in pre-contact Hawai’i. However, deep stream valleys on older Hawaiian Islands often retain the remains of rainfed dryland agriculture on their lower slopes. We evaluated why rainfed agriculture developed on valley slopes on older but not younger islands by comparing soils of Pololū Valley on the young island of Hawai’i with those of Hālawa Valley on the older island of Moloka’i. Alluvial valley-bottom and colluvial slope soils of both valleys are enriched 4–5-fold in base saturation and in P that can be weathered, and greater than 10-fold in resin-extractable P and weatherable Ca, compared to soils of their surrounding uplands. However, due to an interaction of volcanically driven subsidence of the young island of Hawai’i with post-glacial sea level rise, the side walls of Pololū Valley plunge directly into a flat valley floor, whereas the alluvial floor of Hālawa Valley is surrounded by a band of fertile colluvial soils where rainfed agricultural features were concentrated. Only 5% of Pololū Valley supports colluvial soils with slopes between 5° and 12° (suitable for rainfed agriculture), whereas 16% of Hālawa Valley does so. The potential for integrated pondfield/rainfed valley systems of the older Hawaiian Islands increased their advantage in productivity and sustainability over the predominantly rainfed systems of the younger islands

Sex Does Not Affect Survival: A Propensity Score-Matched Comparison in a Homogenous Contemporary Radical Cystectomy Cohort.

OBJECTIVES To determine whether biological sex affects oncological outcome after extended pelvic lymph node dissection, radical cystectomy, and urinary diversion for muscle-invasive bladder cancer, and to identify risk factors impacting outcome. PATIENTS AND METHODS We performed a single-center, retrospective observational cohort study with prospective data collection with a propensity score matched population. A total of 1165 consecutive patients from 2000 to 2020, (317 women and 848 men) scheduled for open extended pelvic lymph node dissection, radical cystectomy, and urinary diversion for urothelial bladder cancer were included in the final analysis. Overall Survival (OS), Cancer-Specific-Survival (CSS), and Recurrence-Free-survival (RFS) were assessed with multivariable weighted Cox regression analysis as well as with propensity score matched Cox-Regression. RESULTS No significant difference was found between sexes regarding OS (HR 1.18, [0.93-1.49], P = .16), CSS (HR 0.87, [0.64-1.18], P = .38), or RFS (HR 0.80, [0.59-1.07], P = .13). These results were confirmed after propensity score matching: female sex was not associated with inferior OS (HR 1.20, [0.91-1.60], P = .19), CSS (HR 1.01, [0.75-1.35], P = .97) or RFS (HR 0.98, [0.75-1.27], P = .86). CONCLUSIONS We did not find a significant difference in cancer-related outcomes or overall survival after extended pelvic lymph node dissection, open radical cystectomy, and urinary diversion for urothelial cancer between males and females even after adjustment with propensity matching score for multiple factors including oncological parameters, smoking status, and renal function