Publications

Charakterisierung der Struktur von plasmapolymerisierten Kohlenwasserstoffen

Configurational Electronic Entropy and the Phase Diagram of Mixed-Valence Oxides: The Cases of Li$_x$FePO$_4$ and Fe$_3$O_4$

Including soil water stress in process-based ecosystem models by scaling down maximum carboxylation rate using accumulated soil water deficit

Gas Adsorption in Flexible COF-506 and COF-506-Cu

Flexible covalent-organic frameworks (COFs) display a variety of guest-dependent dynamic behaviors, but because these are an emerging class of materials, very little experimental adsorption data exists. This work examines the adsorption properties of COF-506 and COF-506-Cu utilizing various adsorbates as probe molecules. These materials have small surface areas (<100 m²/g) but still have significant capacity for methanol and isopropanol compared to activated carbon, even though the COF contains approximately 1/10th the surface area of many activated carbons. Isotherms for ethane/ethylene collected up to 1 bar show moderate selectivity for ethylene, but interestingly, this selectivity is reversed when the isotherms are measured up to 5 bar. The change in selectivity occurs because the ethane isotherm has a distinct stepwise increase in capacity near 4 bar. The adsorption data indicate broad generalizations and analogies of COFs to activated carbon should be avoided; that the adsorption capacity COFs may not correlate to surface area; and that high-pressure adsorption isotherms may have steps in the adsorption isotherm where capacity increases significantly.

CCDC 277431: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Effect of Potential on the Corrosion Fatigue Crack Growth Rate in Type 304 Stainless Steel in Sodium Sulfate Solution at 250°C

Abstract The corrosion fatigue crack growth (FCG) behavior of sensitized Type 304 stainless steel was studied in 0.01m Na2SO4 solution at 250°C. Crack growth rates at different frequencies ranging from 1.0 Hz to 2x10-2 Hz, and at different electrochemical potentials, were measured using a sinusoidal loading waveform at a load ratio R(=Pmin Pmax) of 0. 5. The results show that both the FCG rate and the fracture morphology depends upon the frequency and the applied potential. At a frequency of 2x10-2 Hz, there exists a critical potential (between -450 mVH and -200 mVH) above which the FCG rates are significantly enhanced over those observed at lower potentials. Intergranular cracking was observed above the critical potential, whereas at lower potentials the fracture morphology was principally transgranular in nature. No critical potential was observed at a frequency of 1 Hz, and fracture morphology was entirely transgranular in nature.

VisionArena: 230K Real World User-VLM Conversations with Preference Labels

With the growing adoption and capabilities of vision-language models (VLMs) comes the need for benchmarks that capture authentic user-VLM interactions. In response, we create VisionArena, a dataset of 230K real-world conversations between users and VLMs. Collected from Chatbot Arena - an open-source platform where users interact with VLMs and submit preference votes - VisionArena spans 73K unique users, 45 VLMs, and 138 languages. Our dataset contains three subsets: VisionArena-Chat, 200k single and multi-turn conversations between a user and a VLM; VisionArena-Battle, 30K conversations comparing two anonymous VLMs with user preference votes; and VisionArena-Bench, an automatic benchmark of 500 diverse user prompts that efficiently approximate the live Chatbot Arena model rankings. Additionally, we highlight the types of question asked by users, the influence of response style on preference, and areas where models often fail. We find open-ended tasks like captioning and humor are highly style-dependent, and current VLMs struggle with spatial reasoning and planning tasks. Lastly, we show finetuning the same base model on VisionArena-Chat outperforms Llava-Instruct-158K, with a 17-point gain on MMMU and a 46-point gain on the WildVision benchmark. Dataset at https://huggingface.co/lmarena-ai

Benchmark of Bitrate Adaptation in Video Streaming

The HTTP adaptive streaming technique opened the door to cope with the fluctuating network conditions during the streaming process by dynamically adjusting the volume of the future chunks to be downloaded. The bitrate selection in this adjustment inevitably involves the task of predicting the future throughput of a video session, owing to which various heuristic solutions have been explored. The ultimate goal of the present work is to explore the theoretical upper bounds of the QoE that any ABR algorithm can possibly reach, therefore providing an essential step to benchmarking the performance evaluation of ABR algorithms. In our setting, the QoE is defined in terms of a linear combination of the average perceptual quality and the buffering ratio. The optimization problem is proven to be NP-hard when the perceptual quality is defined by chunk size and conditions are given under which the problem becomes polynomially solvable. Enriched by a global lower bound, a pseudo-polynomial time algorithm along the dynamic programming approach is presented. When the minimum buffering is given higher priority over higher perceptual quality, the problem is shown to be also NP-hard, and the above algorithm is simplified and enhanced by a sequence of lower bounds on the completion time of chunk downloading, which, according to our experiment, brings a 36.0% performance improvement in terms of computation time. To handle large amounts of data more efficiently, a polynomial-time algorithm is also introduced to approximate the optimal values when minimum buffering is prioritized. Besides its performance guarantee, this algorithm is shown to reach 99.938% close to the optimal results, while taking only 0.024% of the computation time compared to the exact algorithm in dynamic programming.

Liquid Chromatography and Mass Spectrometry Analysis of Isoprenoid Intermediates in Escherichia coli

DeepBox: Learning Objectness with Convolutional Networks

Existing object proposal approaches use primarily bottom-up cues to rank proposals, while we believe that objectness is in fact a high level construct. We argue for a data-driven, semantic approach for ranking object proposals. Our framework, which we call DeepBox, uses convolutional neural networks (CNNs) to rerank proposals from a bottom-up method. We use a novel four-layer CNN architecture that is as good as much larger networks on the task of evaluating objectness while being much faster. We show that DeepBox significantly improves over the bottom-up ranking, achieving the same recall with 500 proposals as achieved by bottom-up methods with 2000. This improvement generalizes to categories the CNN has never seen before and leads to a 4.5-point gain in detection mAP. Our implementation achieves this performance while running at 260 ms per image.

Supernova 1988ac in NGC 3995

Consumption of Clarified Grapefruit Juice Ameliorates High-Fat Diet Induced Insulin Resistance and Weight Gain in Mice

To determine the metabolic effects of grapefruit juice consumption we established a model in which C57Bl/6 mice drank 25-50% sweetened GFJ, clarified of larger insoluble particles by centrifugation (cGFJ), ad libitum as their sole source of liquid or isocaloric and sweetened water. cGFJ and control groups consumed similar amounts of liquids and calories. Mice fed a high-fat diet and cGFJ experienced a 18.4% decrease in weight, a 13-17% decrease in fasting blood glucose, a three-fold decrease in fasting serum insulin, and a 38% decrease in liver triacylglycerol values, compared to controls. Mice fed a low-fat diet that drank cGFJ experienced a two-fold decrease in fasting insulin, but not the other outcomes observed with the high-fat diet. cGFJ consumption decreased blood glucose to a similar extent as the commonly used anti-diabetic drug metformin. Introduction of cGFJ after onset of diet-induced obesity also reduced weight and blood glucose. A bioactive compound in cGFJ, naringin, reduced blood glucose and improved insulin tolerance, but did not ameliorate weight gain. These data from a well-controlled animal study indicate that GFJ contains more than one health-promoting neutraceutical, and warrant further studies of GFJ effects in the context of obesity and/or the western diet.

Development of Chiral Ligands for the Transition‐Metal‐Catalyzed Enantioselective Silylation and Borylation of C−H Bonds

Abstract Enantioselective reactions that install functional groups at the positions of unactivated C−H bonds can be envisioned to produce intermediates for the synthesis of the active ingredients in pharmaceuticals and agrochemicals directly from simple feedstocks. Among these C−H bond functionalization reactions, those that form carbon–silicon (C−Si) and carbon–boron (C−B) bonds have been pursued because the products of these reactions can be converted to those containing a wide range of functional groups and because compounds containing silicon and boron possess unique properties that can be valuable for medicinal and materials chemistry. Although the silylation and borylation of C−H bonds have undergone extensive development during the past two decades, enantioselective versions of these reactions were not known until a few years ago. In this Minireview, we present the rapid development of enantioselective silylation and borylation of C−H bonds, with an emphasis on the design and development of the types of chiral ligands needed to achieve these reactions and an intention to inspire an expansion of these types of transformations.

Isoprene Production Via the Mevalonic Acid Pathway in Escherichia coli (Bacteria)

CCDC 1020645: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Effect of absorption on optical enhancement (A)

Review of Medicare, Medicaid, and Commercial Quality of Care Measures: Considerations for Assessing Accountable Care Organizations

Abstract Accountable care organizations (ACOs) have proliferated under the Affordable Care Act (ACA). If ACOs are to improve health care quality and lower costs, quality measures will be increasingly important in determining if provider consolidations associated with the development of ACOs are achieving their intended purpose. This article assesses quality measurement across public and private sectors. We reviewed available quality measures for a subset of programs in six organizations and assessed the number and domain of measures (structure, process, outcomes, and patient experience). Two-thirds of all quality measures were categorized as process measures. Outcome measures made up nearly 20 percent of measures. Patient experience and structure measures made up approximately 8 percent and 7 percent, respectively. We propose further improvements to quality measurement initiatives. For example, programs that reward providers should consider reward size and distribution within the organization. Quality improvement initiatives should consider what encourages provider buy-in and participation and the effects on populations with disproportionate health care needs. As the focus of quality initiatives may change from year to year, measures should be periodically revisited to ensure continued improvement and sustainability. Finally, we suggest quality measures that regulators could use prior to ACO formation or in the year or two following formation.

Retention of inherited argon in alkali feldspar xenocrysts; constraints from Ba diffusion profiles