gebhart/patrepeval huggingface dataset:
Stereoselective Synthesis of Sofosbuvir through Nucleoside Phosphorylation Controlled by Kinetic Resolution (2018)

The preparation of Sofosbuvir, the potent key component of recent Hepatitis C (HCV) infection therapies, is reported. The process is based on the dynamic kinetic resolution of the stereochemically unstable isopropyl‐2‐{[chloro(phenoxy)phosphoryl]‐amino}propanoate ( 8 ). A high stereoselectivity was obtained when the right protective group for 3′‐OH was chosen. Ester and carbonate‐based protective groups gave lower stereoselectivities, but benzyl protection allowed the phosphorylation to occur with a 92:8 ratio in favour of the product with the right configuration at the P‐stereogenic centre. Starting from the γ‐lactone of 2‐deoxy‐2‐fluoro‐2‐methylpentonic acid, the synthesis was accomplished in eight steps in 40 % overall yield using commercially available reagents, and without any enzymatic or chemical resolution technique.
The ephemerizer: making data disappear (2005)

This paper is about how to keep data for a finite time, and then make it unrecoverable after that. It is difficult to ensure that data is completely destroyed. To be available before expiration it is desirable to create backup copies. Then absolute deletion becomes difficult, because even after explicitly deleting it, copies might remain on backup media, or in swap space, or be forensically recoverable. The obvious solution is to store the data encrypted, and then delete the key after expiration. The key is somewhat easier to manage, because it is smaller, but there is still the issue of needing to make the key reliably available for some time, and then reliably destroyed. It is difficult enough for a user to manage one key, much less different keys for different data expiration times. The user could keep each key on a tamper-proof smart card with no copies, but then the data will be lost prematurely if the user loses the smart card. And smart cards are expensive. So the idea in this paper is to concentrate all the key management expense and expertise in one place, a server we call an “ephemerizer”. The ephemerizer creates keys, makes them available for encryption, aids in decryption, and destroys the keys at the appropriate time. The design in this paper ensure that even if a client’s machine gets compromised, and everything in stable storage (including long term user keys) is stolen, any data that has expired before the compromise remains unrecoverable. The paper starts with a description of an existing commercial scheme, and presents improvements to that scheme to eliminate the necessity for per-message state. Then it presents a new approach, based on public keys, and presents an initial design, and then a more efficient version using a new concept closely related to blind signatures, that we call “blind decryption”.
LaSR: A Supple Multi-Connectivity Scheduler for Multi-RAT OFDMA Systems (2018)

Network densification over space and spectrum is expected to be key to enabling the requirements of next generation mobile systems. The pitfall is that radio resource allocation becomes substantially more complex. In this paper, we propose LaSR, a practical multi-connectivity scheduler for OFDMA-based multi-RAT systems. LaSR makes optimal discrete control actions by solving a sequence of simple optimization problems that do not require prior information of traffic patterns. In marked contrast to previous work, the flexibility of our approach allows us to construct scheduling policies that achieve a good balance between system cost and utility satisfaction, while jointly operate across heterogeneous RATs, accommodate real-system requirements, and guarantee system stability. Examples of system requirements considered in this paper include (but are not limited to): constraints on how scheduling data can be encoded onto signaling protocols (e.g., LTE's DCI), delays when turning on/off radio units, or on/off cycles when using unlicensed spectrum. We evaluate our scheduler via a thorough simulation campaign in a variety of scenarios with e.g., mobile users, RATs using unlicensed spectrum (using a duty cycle access mechanism), imperfect queue state information, and constrained signaling protocol.
Quaternionic Representation of the Riesz Pyramid for Video Magnification (2014)

Recently, we presented a new image pyramid, called the Riesz pyramid, that uses the Riesz transform to manipulate the phase in non-oriented sub-bands of an image sequence to produce real-time motion-magnified videos. In this report we give a quaternionic formulation of the Riesz pyramid, and show how several seemingly heuristic choices in how to use the Riesz transform for phase-based video magnifica-tion fall out of this formulation in a natural and principled way. We intend this report to accompany the original paper on the Riesz pyramid for video magnification. 1.
<title>Liquid-crystal-based optical controllers for phased-array antennas</title> (1994)

A 25-channel, 1-bit, free-space, nematic liquid crystal (NLC) spatial light modulator-based optical time delay unit is demonstrated with worst case rf SNRs ranging from 50 to 60 dB for various delay/no-delay modes of operation. Single channel performance demonstrating essentially no crosstalk gives rf SNRs from 74 to 85 dB (all other channels are not fed by optical beams in this mode). A frequency up-conversion method for the phase- based acousto-optic NLC analog optical beamformer is demonstrated at 1015 MHz, showing a record -72.1 dB rf signal power nulling using a parallel-rub NLC device. A novel in-phase and quadrature optical beamformer is demonstrated.
Stable gold nanocolloids with controllable surface modification and functionalization (2012)

This paper demonstrates a new method for fabrication of stable gold nanoparticle-poly(ethylene glycol) (PEG) conjugates with a defined number of PEG molecules. The PEG molecules are directly bound to the surface of gold nanoparticles with almost 100% conjugation efficiency and the PEG surface coverage is tunable between values of 0 and 100%. Gold nanoparticles for the nanoparticle PEG conjugates are prepared by femtosecond laser ablation in liquid of a gold bulk target in deionized water. This method for fabrication of nanoparticles creates gold surfaces which are negatively charged and chemically clean. This facilitates uniform and controlled binding of thiolated PEG molecules to the surface of the gold nanoparticles. The method used to bind PEG to gold can be used with other biomolecules to prepare gold nanoparticles with single or mixed monolayers of biologically important molecules.
Preparation and evaluation of 3,4"-ester derivatives of 16-membered macrolide antibiotics related to tylosin. (1986)

A large group of ester derivatives of tylosin-related macrolides was prepared in which the hydroxyl groups at C-3 and C-4'' were acylated by either chemical or biochemical methods. Most of the derivatives exhibited excellent in vitro antimicrobial activity. However, only the 3,4''-diacyl derivatives of tylosin and macrocin showed any significant improvements of in vivo efficacy against experimental infections in rodents.
A telemetry scheme for ocean acoustic tomography: Real time monitoring (1992)

A new telemetry scheme is described that will make it possible to monitor ocean temperatures in real time using acoustic tomography. The system incorporates autonomous sources mounted on subsurface moorings and receivers that are either cabled to shore or suspended from surface units that drift. The telemetry scheme predicts that the corruption of acoustic travel times, due to wander of the source’s mooring, can be largely eliminated in real time by shifting the start times of the tomographic transmissions in special ways. Corrections to source wander can be obtained without expending battery energy over and above that used in conventional tomography experiments. Standard techniques can be used to correct clock errors at the source in real time.
Tryptophan administration may enhance weight loss by some moderately obese patients on a protein-sparing modified fast (PSMF) diet (1985)

Drugs thought to enhance serotonin-mediated neurotransmission have been shown to diminish appetite for carbohydrates. Therefore, we examined the ability of tryptophan (TRP), serotonin's amino acid precursor, or a placebo to influence weight loss among 62 obese Swiss outpatients who were on a reducing diet [the Protein-Sparing Modified Fast (PSMF) Diet] which can be associated with severe carbohydrate craving. This diet provides relatively large amounts of protein (1.2–1.4 g/kg ideal body weight/day) but little carbohydrate (40 g/day or less), thus stimulating ketone body production. Its consumption also reduces the ratio of plasma TRP to the summed concentrations of the other large neutral amino acids, thereby probably diminishing brain TRP and serotonin levels. During the initial month of the PSMF diet all patients received the placebo; thereafter 30 received TRP (750 mg, twice daily, orally, for 3 months) and 32 the placebo, according to a double-blind protocol. Among moderately obese patients (140–159% of ideal weight; n = 25), the TRP significantly enhanced weight loss (p lt;.05), especially during the first treatment month (3.4 ± 2.8 vs 7.7 ± 1.7 kg lost; means ± standard deviation) but also during the total 3-month test period (2.6 ± 2.3 vs 1.5 ± 1.6 kg lost/month). The JRP didn't modify the reported adherence to the PSMF diet. The partial efficacy of TRP among our moderately obese subjects does not presently justify its routine use as an adjunct to a PSMF diet. However, greater efficacy may be obtained with better patient selection and under metabolic conditions designed to amplify the uptake of TRP into the brain (i.e., administration along with a carbohydrate).
Electromagnetic unidirectionality in magnetic photonic crystals (2003)

We study the effect of electromagnetic unidirectionality, which can occur in magnetic photonic crystals under certain conditions. A unidirectional periodic medium, being perfectly transparent for an electromagnetic wave of certain frequency, ``freezes'' the radiation of the same frequency propagating in the opposite direction. One of the most remarkable manifestations of the unidirectionality is that while the incident radiation can enter the unidirectional slab in either direction with little or even no reflectance, it cannot escape from there getting trapped inside the periodic medium in the form of the coherent frozen mode. Having entered the slab, the wave slows down dramatically and its amplitude increases enormously, creating unique conditions for nonlinear phenomena. Such a behavior is an extreme manifestation of the spectral nonreciprocity, which can only occur in gyrotropic photonic crystals. Unidirectional photonic crystals can be made of common ferro- or ferrimagnetic materials alternated with anisotropic dielectric components. A key requirement for the property of unidirectionality is the proper spatial arrangement of the constitutive components.
A Study on the Improvement of Motion Accuracy of Hexapod-type Parallel Mechanism Machine Tools (2nd Report) (2004)

This paper presents a methodology to calibrate kinematic parameters in a Hexapod-type parallel mechanism machine tool. In a conventional procedure of the DBB (Double Ball Bar) test to measure a machine's contouring accuracy in a circular operation, the center deviation in an error profile is ignored to cancel setup errors. In such a case, the machine's positioning error can be evaluated only locally. We propose to use a specialized jig plate to fix a ball of a DBB device in order to evaluate the machine's positioning error in the global coordinate system. Kinematic parameters in a Hexapod-type parallel mechanism can be calibrated based on contouring error profiles. Experimental comparison shows the machine's global positioning error is significantly improved by using the proposed calibration method. In particular, the parallelity error and the straightness error are reduced by 89% and 76%, respectively, compared to the conventional calibration.
Investigation of a High-Through-Flow, Single-Stage Axial-Flow Compressor with Casing Vortex Generator Configuration 'B' (Configuration 1B). (1980)

Abstract : Complete experimental results are presented from tests of an axial compressor with casing vortex generators. The design objectives were for a flow per unit frontal area of 39.7 lb/sec/ sq ft, a total pressure ratio of 1.912 and a tip speed of 1500 ft/sec. These experimental results were achieved with one of a series of minor parametric modifications to the baseline compressor stage. No conclusions concerning the effects of these modifications will be drawn until the complete series of tests has been reported. (Author)
Controlled Fabrication of Colloidal Semiconductor–Metal Hybrid Heterostructures: Site Selective Metal Photo Deposition (2011)

Reliable synthesis of semiconductor–metal heterostructures would increase their availability for fundamental studies and applications in catalytic, magnetic, and opto-electronic devices. Here, we demonstrate there are three main pathways for the formation of Pt and Pd nanoparticles on CdS and CdS0.4Se0.6 nanorods. A thermal pathway and photochemical pathway occur when the metal precursor is heated or irradiated directly in the presence of an electron donor, leading to homogeneous nucleation and formation of freestanding metal nanoparticles. A separate photochemical pathway occurs in the presence of semiconductor nanorods, leading to exciton formation and quenching by electron trapping at surface defect sites. The localized electrons act as seeding points, leading to heterogeneous nucleation and formation of surface-bound metal nanoparticles. Careful selection of synthetic conditions allows deposition of Pt and Pd particles on CdS and CdS0.4Se0.6 nanorods with a high degree of selectivity (90–95% surface-bound obtained photochemically) over the formation of freestanding metal particles (70–94% unattached under thermal conditions). In addition, metal photo deposition occurs on specific segments of CdS0.4Se0.6 nanorods with compositional anisotropy by taking advantage of the band gap differential between different nanodomains. Irradiation at short wavelengths favors formation of Pd nanoparticles on the large band gap CdS-rich region of the nanorods (57% and 55% at 350 and 420 nm, respectively), while irradiation at longer wavelengths favors the formation of Pd nanoparticles on the small band gap CdSe-rich region of the nanorods (83% at 575 nm). The ability to tune the spatial composition of these and similar heterostructures will impact the ability to engineer and direct energy flows at the nanoscale.
Distributed Kerr Lens Mode-Locked Yb:YAG Thin-Disk Oscillator (2022)

Ultrafast laser oscillators are indispensable tools for diverse applications in scientific research and industry. When the phases of the longitudinal laser cavity modes are locked, pulses as short as a few femtoseconds can be generated. As most high-power oscillators are based on narrow-bandwidth materials, the achievable duration for high-power output is usually limited. Here, we present a distributed Kerr lens mode-locked Yb:YAG thin-disk oscillator which generates sub-50 fs pulses with spectral widths far broader than the emission bandwidth of the gain medium at full width at half maximum. Simulations were also carried out, indicating good qualitative agreement with the experimental results. Our proof-of-concept study shows that this new mode-locking technique is pulse energy and average power scalable and applicable to other types of gain media, which may lead to new records in the generation of ultrashort pulses.
Synthesis and Biological Activity of 2-(3′-Hydroxypropylidene)-1α-hydroxy-19-norvitamin D Analogues with Shortened Alkyl Side Chains (2011)

As a continuation of our efforts directed to vitamin D compounds of promising biological properties, 19-norvitamins 9-13, possessing a 3'-hydroxypropylidene fragment attached to C-2 and shortened 17β-alkyl chains, were synthesized. A new synthetic pathway providing the CD-ring ketones 20-24 is described starting from the epimeric aldehydes 25 and 26. The hydrindanones 20-24 were subjected to the Wittig-Horner reaction with the phosphine oxide 14, and the vitamin D compounds 9-13 were obtained after hydroxyl deprotection. In comparison to 1α,25-(OH)(2)D(3) (1), the prepared analogues, except for the 20R-compound 12, were only ca. 3 times less potent in binding to VDR. Compounds 9-11 and 13 exhibited HL-60 cellular activity 5-20 times lower and transcriptional activity ca. 10 times decreased related to those for the hormone 1. When tested in vivo, all the analogues showed no ability to mobilize calcium from bone, and intestinal calcium transport activity was observed only at high doses of the vitamins 10, 12, and 13.
Advancements in data-driven respiratory motion extraction methods for clinical list-mode 18F-FDG PET datasets acquired from a commercial PET scanner (2017)

We have significantly improved four data-driven respiratory motion (RM) extraction methods for various activity distributions in clinical myocardial perfusion (MP) and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F-FDG PET datasets. They are activity distributions: (1) with high myocardial uptake, (2) same as (1) but with portion of the heart outside the image, and with high image intensity (3) in the liver and (4) in the lung area without attenuation compensation. In Method #1, a 3D volume-of-interest (VOI) was placed over the heart region of the PET image obtained from the total acquisition time period. The surrogate RM signals were obtained from the centroids of the image intensity of the myocardial activity uptake within the same VOI of PET images obtained from rebinned list-mode data in short time intervals. The Fourier Transform (FT) of the time sequence of surrogate RM signals and smoothing reveal the RM peak and its average period, Pav. In Methods #2, #3, and #4, specially-shaped 3D VOIs were placed over the heart, the top of the liver, and the bottom of the lungs, respectively. Then, the same procedures used in Method #1 were employed except using the total counts within the corresponding VOI. The location, sizes and shapes of the VOIs were optimized for the highest signal-to-noise (S/N) in the RM peak extraction. The improved RM extraction methods were evaluated using 14 patient datasets. Method #1 was shown to work well for 79% of the datasets, and Pav showing high S/N and excellent agreement (Pearson correlation coefficient 0.997) with those obtained from an external RM monitoring belt system. Method #2 was applied successfully to 14%, and Methods #3 and #4 to the rest of datasets. Excellent agreements were also found in cross comparison between the methods. We conclude that the improved data-driven RM extraction methods which showed successful results in various PET image datasets will provide an important first step for the motion compensation application in commercial PET scanners.
Placement of replicated message mediation components (2007)

In this paper, we propose a technique for placing components of mediation flows within a Message-Oriented Middleware where components can be replicated. A mediation flow is a directed acyclic graph of message transformations (also known as mediations) connecting sources and sinks of messages. The source nodes correspond to producers, who enter messages into the middleware; the sink nodes correspond to consumers, who receive results derived from the input messages. All other nodes in the graph represent transformations of messages in the middleware. A placement is an assignment of nodes of the mediation flow graph to physical machines (brokers) in a distributed network.
Development of a Rechargeable Zinc-Air Battery (2010)

An electrically rechargeable zinc-air cell was developed and demonstrated using a bi-electrode on the cathode side and a 3D zinc electrode. About 200 cycles corresponding to 5000h of operation was achieved with this configuration. An innovating hybrid bi-electrode was evaluated which significantly increase the energy efficiency of our system to about 70% with an energy density close to 110 wh/kg and also improves the power response of the zinc air battery for punctual power demand application.
View Compensated Compression of Volume Rendered Images for Remote Visualization (2009)

Remote visualization of volumetric images has gained importance over the past few years in medical and industrial applications. Volume visualization is a computationally intensive process, often requiring hardware acceleration to achieve a real time viewing experience. One remote visualization model that can accomplish this would transmit rendered images from a server, based on viewpoint requests from a client. For constrained server-client bandwidth, an efficient compression scheme is vital for transmitting high quality rendered images. In this paper, we present a new view compensation scheme that utilizes the geometric relationship between viewpoints to exploit the correlation between successive rendered images. The proposed method obviates motion estimation between rendered images, enabling significant reduction to the complexity of a compressor. Additionally, the view compensation scheme, in conjunction with JPEG2000 performs better than AVC, the state of the art video compression standard.