gebhart/patrepeval huggingface dataset:
Continuous-Flow Alkane Dehydrogenation by Supported Pincer-Ligated Iridium Catalysts at Elevated Temperatures (2018)

Pincer-ligated iridium complexes of the form [Ir(R4PCP)L] (R4PCP = κ3-C6H3-2,6-(XPR2)2; X = CH2, O; R = tBu, iPr) are efficient homogeneous alkane dehydrogenation catalysts that have been reported to be highly active at temperatures of 240 °C or below. In this work, silica-supported [Ir(C2H4)(p-tBu2PO-tBu4POCOP)] (1/SiO2) was used to study a model continuous-flow gas-phase acceptorless alkane dehydrogenation system. This particular supported framework is thermally stable at temperatures up to 340 °C, 100 °C above the highest temperature at which analogous homogeneous complexes have been reported to show stable activity, with observed butane dehydrogenation rates of ca. 80 molbutenes molcat.–1 h–1. Solid-state 31P MAS NMR and ATR IR are used to demonstrate that the backbone pincer ligand remains intact and coordinated at 340 °C. The complex is fully converted to [Ir(CO)(p-tBu2PO-tBu4POCOP)] (3/SiO2) above 300 °C. 3/SiO2 is observed to be catalytically active at the higher temperatures tested, and reaction rates are comparable to those of 1/SiO2. 3/SiO2 and 1/SiO2 act as resting states for the active 14-electron fragment, through dissociation of the CO or olefin ligand, respectively. Given that 3/SiO2 is air resistant at ambient temperature and is structurally stable and catalytically active at elevated temperatures, it is a suitable candidate as a catalyst for the highly endothermic acceptorless dehydrogenation of alkanes.
Structure- and NMR-based design of novel Bcl-xL antagonists. (2008)

1278 Pro- and anti-apoptotic members of the Bcl-2 (B-cell lymphocyte/leukemia-2) family of proteins are central regulators of the apoptotic machinery. Over-expression of anti-apoptotic Bcl-2-family proteins, such as Bcl-2, Bcl-xL, Mcl-1, Bfl-1, Bcl-W and Bcl-B, occurs during the pathogenesis or progression of most cancers and leukemias, rendering these proteins potential drug targets. A hydrophobic groove on the surface of the anti-apoptotic Bcl-2 proteins is responsible for sequestering respective pro-apoptotic counterparts that bind via a conserved hetero-dimerization α-helical region, also known as the BH3 domain. We describe a variety of structure and NMR-guided fragment-based approaches to derive novel BH3 mimetics. Preliminary ADME properties as well as cell-based and subsequent in vivo efficacy evaluations of the most potent compounds will be reported.
Polymer Nanoparticle-Based Spherical Photonic Pigments for Dye-Free Noniridescent Bright Coloring (2021)

While the color of conventional pigments and dyes is related to the absorption of light, structural color results from selective light scattering by nanostructures with an appropriate periodic variation of refractive index. The latter can be obtained from virtually any material and produce a coloration that appears considerably brighter and is more resistant to fading. We developed colloidal photonic pigments with spherical symmetry from polymer nanoparticles (PNP) of styrene and acrylate monomers, using their surface charge to control the self-assembly by droplet microfluidic emulsification. By changing only the size of the PNPs, we are able to produce colors across the entire visible spectra. Unlike most other spherical photonic pigments, our materials present bright saturated colors and virtually no iridescence. We achieved this by doping the pigments with polydopamine (PD) nanoparticles. The latter can both reduce the long-range order in the photonic pigments and absorb the diffuse light scattering from structural defects, as shown by electronic microscopy and reflective confocal microscopy (RCM). Nanostructured PD-doped spherical photonic pigments can be obtained from sustainable materials and hold enormous potential for technological applications from dye-free color coatings to stimuli-responsive coloring, dye-free colorimetric sensors, and reflective color screens.
Spin-Weighted Spherical CNNs (2020)

Learning equivariant representations is a promising way to reduce sample and model complexity and improve the generalization performance of deep neural networks. The spherical CNNs are successful examples, producing SO(3)-equivariant representations of spherical inputs. There are two main types of spherical CNNs. The first type lifts the inputs to functions on the rotation group SO(3) and applies convolutions on the group, which are computationally expensive since SO(3) has one extra dimension. The second type applies convolutions directly on the sphere, which are limited to zonal (isotropic) filters, and thus have limited expressivity. In this paper, we present a new type of spherical CNN that allows anisotropic filters in an efficient way, without ever leaving the spherical domain. The key idea is to consider spin-weighted spherical functions, which were introduced in physics in the study of gravitational waves. These are complex-valued functions on the sphere whose phases change upon rotation. We define a convolution between spin-weighted functions and build a CNN based on it. The spin-weighted functions can also be interpreted as spherical vector fields, allowing applications to tasks where the inputs or outputs are vector fields. Experiments show that our method outperforms previous methods on tasks like classification of spherical images, classification of 3D shapes and semantic segmentation of spherical panoramas.
ChemInform Abstract: NUCLEOPHILIC AROMATIC SUBSTITUTION OF CR(CO)3 COMPLEXED DIHALOARENES WITH THIOLATES (1984)

Abstract Die Chromcarbonylverbindungen (II) werden in DMSO oder unter Phasentransfer‐Bedingungen mit Thiolaten zu Mono‐ (IV) und Disubstitutions‐Produkten (V) umgesetzt, die oxidativ zu (VI) und (VII) gespalten werden.
Kinetics of isotropic-smectic phase transition in liquid-crystalline polyethers (1990)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of isotropic-smectic phase transition in liquid-crystalline polyethersHaakan Jonsson, Elisabet Wallgren, Anders Hult, and Ulf W. GeddeCite this: Macromolecules 1990, 23, 4, 1041–1047Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://pubs.acs.org/doi/10.1021/ma00206a022https://doi.org/10.1021/ma00206a022research-articleACS PublicationsRequest reuse permissionsArticle Views82Altmetric-Citations30LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Probing kinetic enhancement of β-galactosidase-nanoparticle complexes (Conference Presentation) (2018)

Enhancement in enzymatic activity after attachment to nanoparticle surfaces has been observed in numerous enzyme systems, although the underlying mechanism for these enhancements remains largely unknown. This work explores the utility of a model based on a reaction scheme that takes into account some of the many interactions between substrate, product, and nanoparticle that can occur. This model was utilized to make predictions about the type of behavior that should manifest itself with quantum dots peripherally displayed around beta-galactosidase (&beta-gal) and confirmed empirically. &beta-gal is a homotetrameric enzyme which at ~465 kDa is significantly larger than the 4.2 nm diameter green emitting quantum dots utilized to decorate its periphery. Because &beta-gal operates near the diffusion limit, this provides an opportunity to selectively investigate certain aspects of enzyme enhancement when attached to a nanoparticle with minimal perturbation to the native enzyme structure. Enzymatic assays were performed with both free enzyme and quantum dot-decorated enzymes in a side-by-side format where kinetic processes were challenged by increasing viscosity with glycerol and competitive inhibitors such as lactose. The results from this model suggest it is possible to achieve significant enhancements in a diffusion limited enzyme’s catalytic rate (< i>k< sub>cat< sub>< i>) after NP attachment without substantial changes to the enzyme’s structure or function. Because cell free synthetic biology is gaining importance, this approach will yield insights on how enzymes can be utilized ex vivo and how being attached to NP scaffolds yields kinetic enhancement, possibly through enhanced product dissociation.
Detection of Fetal Single Gene Mutations through Targeted Sequencing of Maternal cell-free DNA (2020)

Non-invasive prenatal tests are available for chromosomal aneuploidy but not for monogenic diseases yet. This study aimed to develop analysis method for detecting fetal mutation status by using only maternal blood sample. We introduce two different approaches to detect a fetal mutation of the Duchene Muscular Dystrophy (DMD) gene. The algorithms are consisted of two steps: detection of mutation types and regions and determination of fetal mutation status. For the second step, one approach uses allele frequencies of heterozygous sites and the other approach uses relative read depth that is the read depths of cfDNA divided by gDNA of the mother.
The free form XR photovoltaic concentrator: a high performance SMS3D design (2008)

A novel photovoltaic concentrator is presented. The goal is to achieve high concentration design with high efficiency and high acceptance angle that in the same time is compact and convenient for thermal and mechanical management. This photovoltaic system is based on 1 cm<sup>2</sup> multi-junction tandem solar cells and an XR concentrator. The XR concentrator in this system is an SMS 3D design formed by one reflective (X) and one refractive (R) free-form surfaces (i.e., without rotational or linear symmetry) and has been chosen for its excellent aspect ratio and for its ability to perform near the thermodynamic limit. It is a mirror-lens device that has no shadowing elements and has square entry aperture (the whole system aperture area is used for collecting light). This large acceptance angle relaxes the manufacturing tolerances of all the optical and mechanical components of the system included the concentrator itself and is one of the keys to get a cost competitive photovoltaic generator. For the geometrical concentration of 1000x the simulation results show the acceptance angle of &plusmn;1.8 deg. The irradiance distribution on the cell is achieved with ultra-short homogenizing prism, whose size is optimised to keep the maximum values under the ones that the cell can accept. The application of the XR optics to high-concentration is being developed in a consortium leaded by The Boeing Company, which has been awarded a project by US DOE in the framework of the Solar America Initiative.
Limits of stereopsis explained by local cross-correlation (2009)

Human stereopsis has two well-known constraints: the disparity-gradient limit, which is the inability to perceive depth when the change in disparity within a region is too large, and the limit of stereoresolution, which is the inability to perceive spatial variations in disparity that occur at too fine a spatial scale. We propose that both limitations can be understood as byproducts of estimating disparity by cross-correlating the two eyes' images, the fundamental computation underlying the disparity-energy model. To test this proposal, we constructed a local cross-correlation model with biologically motivated properties. We then compared model and human behaviors in the same psychophysical tasks. The model and humans behaved quite similarly: they both exhibited a disparity-gradient limit and had similar stereoresolution thresholds. Performance was affected similarly by changes in a variety of stimulus parameters. By modeling the effects of stimulus blur and of using different sizes of image patches, we found evidence that the smallest neural mechanism humans use to estimate disparity is 3-6 arcmin in diameter. We conclude that the disparity-gradient limit and stereoresolution are indeed byproducts of using local cross-correlation to estimate disparity.
Applicability of e-beam mask inspection to EUV mask production (2012)

Ever since the 180nm technology node the semiconductor industry has been battling the sub-wavelength regime in optical lithography. During the same time development for a 13.5nm Extreme Ultraviolet [EUV] solution has been in development, which would take us back from a &#955;/10 to a &gt;&#955; regime again - at least for one node. Add to this the potential to increase the wafer size as well, and we are at a major crossroads. The introduction of EUV has been marred by many delays, but we are finally seeing the hardware development efforts converge and multiple customers around the world embarking on this adventure. As it becomes clear that this preproduction phase will occur at or below 20nmHP, it also becomes clear that this will happen at the limiting edge of existing 19x-based patterned mask inspection technology, reaching the practical resolution limits at around 20nm HP mask densities. Resolution is coupled with sensitivity and throughput such that the extended sensitivity may come at an unreasonable throughput. Loss of resolution also badly impacts defect dispositioning, or classification, which becomes impractical. As resolution is especially critical for die to database inspection, single die masks and masks with high flare bias are at risk of not being inspectable with 19xnm based inspectors. E-Beam based mask inspection has been proposed and demonstrated as a viable technology for patterned EUV mask inspection. In this paper, we study the key questions of sensitivity and throughput, in both die-to-die and die-to-database applications. We present new results, based on a new generation of E-Beam inspection technology, which has a higher data rate at smaller spot sizes. We will demonstrate the feasibility of acceptable inspection time with EBMI. We also will discuss die-to-data-base inspection and the advantage of using E-Beam imaging for meeting future requirements of single- die EUV masks.
Learned Garbage Collection (2020)

Several programming languages use garbage collectors (GCs) to automatically manage memory for the programmer. Such collectors must decide when to look for unreachable objects to free, which can have a large performance impact on some applications. In this preliminary work, we propose a design for a learned garbage collector that autonomously learns over time when to perform collections. By using reinforcement learning, our design can incorporate user-defined reward functions, allowing an autonomous garbage collector to learn to optimize the exact metric the user desires (e.g., request latency or queries per second). We conduct an initial experimental study on a prototype, demonstrating that an approach based on tabular Q learning may be promising.
Three-dimensional coherence imaging in the Fresnel domain (1999)

We show that three-dimensional incoherent primary sources can be reconstructed from finite-aperture Fresnel-zone mutual intensity measurements by means of coordinate and Fourier transformation. The spatial bandpass and impulse response for three-dimensional imaging that result from use of this approach are derived. The transverse and longitudinal resolutions are evaluated as functions of aperture size and source distance. The longitudinal resolution of three-dimensional coherence imaging falls inversely with the square of the source distance in both the Fresnel and Fraunhofer zones. We experimentally measure the three-dimensional point-spread function by using a rotational shear interferometer.
Boosting stability of electronic multi-gas sensors (2022)

Conventional electronic gas sensors are designed with a single-output response (e.g. resistance, current). Under variable ambient conditions such sensors suffer from fluctuations (drift) of their response because single-output sensor designs mathematically do not allow for drift correction. We break this status quo by developing a new generation of gas sensors, known as multivariable sensors with several independent responses. Previously, we showed that individual multivariable gas sensors quantify several gases and reject interferences. Here we show that such multivariable gas sensors have the ability for self-correction for sensor drift. Our multivariable gas sensors described here operate in the radio-frequency (RF) portion of the electromagnetic spectrum and utilize dielectric excitation of semiconducting metal oxide materials on the shoulder of their dielectric relaxation peak. We self-correct for the baseline drift by sensor operation at more than one RF frequency. Our approach for the drift self-correction should allow implementations of gas sensors in diverse applications that cannot afford weekly, monthly, or quarterly periodic maintenance, typical of traditional analytical instruments.
Balancing protection and release of DNA: tools to address a bottleneck of non-viral gene delivery (2009)

Engineering polymeric gene-delivery vectors to release an intact DNA payload at the optimal time and subcellular compartment remains a formidable challenge. An ideal vector would provide total protection of complexed DNA from degradation prior to releasing it efficiently near or within the nucleus of a target cell. While optimization of polymer properties, such as molecular weight and charge density, has proved largely inadequate in addressing this challenge, applying polymeric carriers that respond to temperature, light, pH and redox environment to trigger a switch from a tight, protective complex to a more relaxed interaction favouring release at the appropriate time and place has shown promise. Currently, a paucity of gene carriers able to satisfy the contrary requirements of adequate DNA protection and efficient release contributes to the slow progression of non-viral gene therapy towards clinical translation. This review highlights the promising carrier designs that may achieve an optimal balance of DNA protection and release. It also discusses the imaging techniques and three-dimensional in vitro models that can help study these two barriers in the non-viral gene transfer process. Ultimately, efficacious non-viral gene therapy will depend on the combination of intelligent material design, innovative imaging techniques and sophisticated in vitro model systems to facilitate the rational design of polymeric gene-delivery vectors.
Design optimization of spoke-type PM motors for Formula E racing cars (2016)

This paper presents the performance trade-offs in the design optimization of spoke-type permanent magnet (PM) motors for high speed and very high torque density traction motors. An example 18-slot 16-pole machine for a direct drive Formula E race car over the Le Mans driving cycle is considered. Both low speed and extended speed/field-weakening operations are evaluated using high fidelity finite element (FE) simulations, to simultaneously increase the torque density and decrease the power losses over the high energy-throughput-zones of the machine torque-speed plane. The results of the design optimization process yielding 3,400 design candidates are utilized to quantify the performance trade-offs for increasing the power density in spoke-type PM motors. These trade-offs include the impacts on other performance metrics such as power losses, PM demagnetization, and torque ripple. The analysis is supplemented by multi-physics simulation of three counterpart optimized designs, and successful experimental verification of a prototype of one of those three designs which represents a record high power density motor in traction applications.
Ligand binding modes from low resolution GPCR models and mutagenesis: chicken bitter taste receptor as a test-case (2017)

Bitter taste is one of the basic taste modalities, warning against consuming potential poisons. Bitter compounds activate members of the bitter taste receptor (Tas2r) subfamily of G protein-coupled receptors (GPCRs). The number of functional Tas2rs is species-dependent. Chickens represent an intriguing minimalistic model, because they detect the bitter taste of structurally different molecules with merely three bitter taste receptor subtypes. We investigated the binding modes of several known agonists of a representative chicken bitter taste receptor, ggTas2r1. Because of low sequence similarity between ggTas2r1 and crystallized GPCRs (~10% identity, ~30% similarity at most), the combination of computational approaches with site-directed mutagenesis was used to characterize the agonist-bound conformation of ggTas2r1 binding site between TMs 3, 5, 6 and 7. We found that the ligand interactions with N93 in TM3 and/or N247 in TM5, combined with hydrophobic contacts, are typically involved in agonist recognition. Next, the ggTas2r1 structural model was successfully used to identify three quinine analogues (epiquinidine, ethylhydrocupreine, quinidine) as new ggTas2r1 agonists. The integrated approach validated here may be applicable to additional cases where the sequence identity of the GPCR of interest and the existing experimental structures is low.
IL-12 priming and selective IL-2Rα engagement leads to enhanced CD8+ T cell persistence and anti-tumor immunity in the absence of lymphodepletion. (P1424) (2013)

Abstract Effective T cell therapy against metastatic cancer requires high frequencies of functional tumor-reactive T cells. However, achieving sustained and elevated levels of tumor-reactive T cells has proven difficult and usually requires highly toxic preconditioning of patients with radiation or chemotherapy to destroy host lymphocytes and suppressive cells. Using the mouse CD8+ T cell pmel-1 TCR transgenic model, we found that the combination of 1) in vitro IL-12-priming of donor T cells during activation and 2) the administration of IL-2/anti-IL-2 mAb complexes after adoptive transfer promoted the dramatic and systemic increase in tumor-reactive T cells in the absence of host lymphodepletion. Importantly, this combinatorial therapy led to the cure of over half of mice with established subcutaneous B16 tumors. Interestingly, while IL-2/anti-IL-2 mAb complexes synergized with ex vivo IL-12-priming, IL-15/sIL-15Rα-Fc complexes failed to mediate comparable synergistic activity despite signaling through the shared IL-2Rβγ subunits. Given that IL-12 priming strongly promotes the upregulation of the high affinity IL-2 receptor subunit, IL-2Rα, our results suggest that selective IL-2Rα engagement uniquely promotes T cell persistence and anti-tumor efficacy in the absence of lymphodepletion. Our findings underscore the importance of T cell polarizing conditions in dictating the requirement of adoptively transferred T cells for exogenous cytokine.
ChemInform Abstract: Ring Closing Alkyne Metathesis. Comparative Investigation of Two Different Catalyst Systems and Application to the Stereoselective Synthesis of Olfactory Lactones, Azamacrolides, and the Macrocyclic Perimeter of the Marine Alkaloid Nakadomarin A. (2000)

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.