gebhart/patrepeval huggingface dataset:
Resolution limit of cylinder diameter estimation by diffusion MRI: The impact of gradient waveform and orientation dispersion (2017)

Diffusion MRI has been proposed as a non-invasive technique for axonal diameter mapping. However, accurate estimation of small diameters requires strong gradients, which is a challenge for the transition of the technique from preclinical to clinical MRI scanners, since these have weaker gradients. In this work, we develop a framework to estimate the lower bound for accurate diameter estimation, which we refer to as the resolution limit. We analyse only the contribution from the intra-axonal space and assume that axons can be represented by impermeable cylinders. To address the growing interest in using techniques for diffusion encoding that go beyond the conventional single diffusion encoding (SDE) sequence, we present a generalised analysis capable of predicting the resolution limit regardless of the gradient waveform. Using this framework, waveforms were optimised to minimise the resolution limit. The results show that, for parallel cylinders, the SDE experiment is optimal in terms of yielding the lowest possible resolution limit. In the presence of orientation dispersion, diffusion encoding sequences with square-wave oscillating gradients were optimal. The resolution limit for standard clinical MRI scanners (maximum gradient strength 60-80 mT/m) was found to be between 4 and 8 μm, depending on the noise levels and the level of orientation dispersion. For scanners with a maximum gradient strength of 300 mT/m, the limit was reduced to between 2 and 5 μm.
Respiration with Sulfate as Electron Acceptor (2018)

Two genera of strictly anaerobic bacteria, Desulfovibrio and Desulfotomaculum, are capable of utilizing sulfate (or reduced products thereof) as terminal electron acceptor for catabolic oxidation processes. There is some evidence that the intracellular pH of sulfate reducing bacteria lies between 7 and 8. Since, however, the intracellular concentration of sulfite and the physiological electron donor are not known, it is impossible to decide which products are formed by bisulfite reductase in vivo. The formation of thiosulfate by the enzyme is dependent on the simultaneous presence of bisulfite. The presence of the thiosulfate-forming enzyme and of thiosulfate reductase in sulfate-reducing bacteria has been taken as evidence that dissimilatory sulfate reduction proceeds via trithionate and thiosulfate. It is therefore conceivable that both the thiosulfate-forming enzyme and thiosulfate reductase have a function only when the bacteria are growing in the presence of trithionate or thiosulfate.
Autologous blood donation for surgery in inflammatory bowel disease--a report of six cases. (1999)

Preoperative autologous blood donation is save and feasible in IBD patients with elective bowel resection.
Minimum variance adaptive beamforming applied to medical ultrasound imaging (2006)

We have applied the minimum variance beam- former to medical ultrasound imaging and shown significant improvement in image quality compared to delay-and-sum. Reduced mainlobe width and suppression of sidelobes is demonstrated on both simulated and experimental RF data of closely spaced wire targets, resulting in increased resolution and contrast. The method has been applied to experimental RF data from a heart-phantom, demonstrating improved definition of the ventricular walls. We have evaluated the beamformers sensitivity to velocity errors and shown that reliable amplitude estimates are achieved if proper regular- ization is applied. I. INTRODUCTION Delay-and-sum (DAS) beamforming is the standard technique in medical ultrasound imaging. An image is formed by transmitting a narrow beam in a number of angles and dynamically delaying and summing the received signals from all channels. The large sidelobes of the DAS beamformer can be suppressed using aperture shading, resulting in increased contrast at the expense of resolution. In contrast to the predetermined shading in DAS, adaptive beamformers use the recorded wavefield to compute the aperture weights. By suppressing inter- fering signals from off-axis directions and allowing large sidelobes in directions where there is no received energy, the adaptive beamformers can increase resolution. The minimum variance (MV) adaptive beamformer (1) and subspace-based methods have mostly been studied in narrowband applications. Extensions to broadband imaging include preprocessing with focusing- and spa- tial resampling filters, allowing narrowband methods to be used on broadband data (2), (3). We have applied the MV beamformer to medical ultrasound imaging by prefocusing in the direction of the transmitted beam - as the delay-step in DAS - and replaced the summing with the MV method. Similar methods have been used by Mann and Walker (4), and Sasso and Cohen-Bacrie (5) in medical ultrasound imaging. The former use a con- strained adaptive beamformer on experimental data of a single point target and a cyst phantom demonstrating improved contrast and resolution, whereas the latter use an MV beamfomer on a simulated data-set, showing improved contrast in the final image. We demonstrate resolution improvement and sidelobe suppression on both simulated and experimental RF data of closely spaced wire targets, and show improvement in the image of a heart-phantom obtained from experimental RF data. We also evaluate robustness of the beamformer to errors in acoustic velocity, and show that reliable amplitude estimates are achieved by regularization.
Effects of Multiple Sources in the Contact Conductance Theory (1979)

An analysis of regularly spaced disk sources on the surface of a semi-infinite body is given and related to steady-state contact conductance theory. It is shown that simple superposition utilizing the steady-state temperature distribution for a single typical disk source is not valid since a steady state does not exist for the temperature resulting for an infinite number of regularly spaced sources on the surface of a semi-infinite solid. A novel analysis is presented that treats the transient surface temperature in such a manner that a steady-state conductance is derived. The conductance results are compared with those obtained by Yovanovich who use a complementary analysis. The method of analysis can be applied to other disk spacings and to random distribution of contacts. Also considered is the case of contact radius being a uniformly-distributed random variable which yielded the results of increased contact resistance compared to that using the average contact radius.
Propagation effects and antenna properties and their impact on ED receivers' performance in body sensor network (2014)

In this paper, we demonstrate the performance of a system built according to the IEEE Std. 802.15.4-2011 impulse radio ultra wideband (UWB) definitions. We have constructed a physical layer transceiver simulation model with energy detector receivers and a medium access control layer sensor network analysis model with slotted Aloha (S-ALOHA) protocol. The used channel models in the transceiver system are two different body area network channel models. In the results, the receiver structure is shown to affect 2-4 dB and the used channel 3-5 dB on system level performance. Additionally, we have designed a UWB antenna suitable for body worn devices and have studied its performance characteristics with different distances from the human body. As a conclusion, besides observing the impact of the channel model and the receiver structure, we are also able to estimate the effect of the antenna - human body distance to the system level performance.
Intrinsic Kinetics of 3-Hydroxypropanal Hydrogenation over Ni/SiO2/Al2O3 Catalyst (1997)

The hydrogenation of 3-hydroxypropanal (HPA) to 1,3-propanediol (PD) over Ni/SiO2/Al2O3 catalyst powder was carried out at 318−353 K and 2.60−5.15 MPa in a batchwise-operated stirred autoclave. A kinetic model which can well describe the reactions of this process was developed. The model parameters were estimated by the maximum likelihood function of the concentration of HPA and PD according to concentration−time profiles measured at different temperatures and pressures. To obtain high selectivity of PD the reaction temperature should be lower than 333 K.
The Bicyclo[2.2.2]octane Motif: A Class of Saturated Group 14 Quantum Interference Based Single-Molecule Insulators (2018)

The electronic transmission through σ-conjugated molecules can be fully suppressed by destructive quantum interference, which makes them potential candidates for single-molecule insulators. The first molecule with clear suppression of the single-molecule conductance due to σ-interference was recently found in the form of a functionalized bicyclo[2.2.2]octasilane. Here we continue the search for potential single-molecule insulators based on saturated group 14 molecules. Using a high-throughput screening approach, we assess the electron transport properties of the bicyclo[2.2.2]octane class by systematically varying the constituent atoms between carbon, silicon, and germanium, thus exploring the full chemical space of 771 different molecules. The majority of the molecules in the bicyclo[2.2.2]octane class are found to be highly insulating molecules. Though the all-silicon molecule is a clear-cut case of σ-interference, it is not unique within its class and there are many potential molecules that we predict to be more insulating. The finding of this class of quantum interference based single-molecule insulators indicates that a broad range of highly insulating saturated group 14 molecules are likely to exist.
Enhanced channel coding using source criteria in speech coders (1994)

Spectral efficiency in digital voice communications in personal communications networks is primarily provided for by advanced speech coding techniques. A threat to the quality and low bit rate requirements of these speech coders is imposed by the transmission channel. Channel coding is thus considered mandatory, but its performance is limited to specific channel conditions and system constraints like bandwidth and transmission power. The authors describe a technique for exploiting source redundancy in speech coders for further improving the performance of the channel coding scheme without the obligatory increased redundancy.
Short chain oligogalacturonides induce ethylene production and expression of the gene encoding aminocyclopropane 1-carboxylic acid oxidase in tomato plants (1998)

Oligogalacturonic acids (OGAs), derived from plant cell wall pectin, have been implicated in a number of signal transduction pathways involved in growth, development and defense responses of higher plants. This study investigates the size range of OGAs capable of inducing ethylene synthesis in tomato plants, and demonstrates that in contrast with many other effects, only short chain OGAs are active. Oligomers across a range of DP from 2-15 were separated and purified to homogeneity by QAE-Sephadex anion exchange chromatography using a novel elution system. The OGAs were applied to tomato plants and assayed for their ability to induce ethylene gas release and changes in steady state levels of mRNA encoding the ethylene forming enzyme aminocyclopropane-1-carboxylic acid oxidase (ACO). The study demonstrated that only OGAs in the size range of DP4-6 were active both in eliciting ACO expression and in the production of ethylene.
Gemcitabine Eliminates Double Minute Chromosomes from Human Ovarian Cancer Cells (2013)

Double minute chromosomes are cytogenetic manifestations of gene amplification frequently seen in cancer cells. Genes amplified on double minute chromosomes include oncogenes and multi-drug resistant genes. These genes encode proteins which contribute to cancer formation, cancer progression, and development of resistance to drugs used in cancer treatment. Elimination of double minute chromosomes, and therefore genes amplified on them, is an effective way to decrease the malignancy of cancer cells. We investigated the effectiveness of a cancer drug, gemcitabine, on the loss of double minute chromosomes from the ovarian cancer cell line UACC-1598. Gemcitabine is able to decrease the number of double minute chromosomes in cells at a 7500X lower concentration than the commonly used cancer drug hydroxyurea. Amplified genes present on the double minute chromosomes are decreased at the DNA level upon gemcitabine treatment. Gemcitabine, even at a low nanomolar concentration, is able to cause DNA damage. The selective incorporation of double minutes chromatin and γ-H2AX signals into micronuclei provides a strong link between DNA damage and the loss of double minute chromosomes from gemcitabine treated cells. Cells treated with gemcitabine also showed decreased cell growth, colony formation, and invasion. Together, our results suggest that gemcitabine is effective in decreasing double minute chromosomes and this affects the biology of ovarian cancer cells.
Zinc diffusion process for GaAs/sub 0.6/P/sub 0.4/ red light emitting diode fabrication in an undergraduate laboratory (2002)

The formation of p/sup +/-n junctions by zinc diffusion into n-type GaAs/sub 0.6/P/sub 0.4/ wafers is described. Processes developed in this work allow experience with chemical vapor deposition and the fabrication of red LEDs in an undergraduate laboratory with minimal student exposure to hazardous chemicals. Electrical and optical characteristics of the resulting LEDs are presented.
Nanostructured crystals of fluorite phases Sr1 − x R x F2 + x (R = Y, La-Lu) and their ordering: Part III. A study of the refractive indices (2009)

The refractive indices n of Sr1 − x R x F2 + x crystals (R = Y, La-Lu; 0 ≤ x ≤ 0.5) have been measured at wavelengths of 0.436, 0.546, and 0.589 μm. It is established that n increases when there is an increase in the RF3 content x according to a weakly quadratic law for each R. For the isoconcentration series of Sr0.9 R 0.1F2.1 crystals, the change in n in the series of rare earth elements has a pronounced nonlinear character, which reflects the nonmonotonous change in the properties of compounds in the R series. It is shown that the method of molecular refraction additivity can be used to calculate n for Sr1 − x R x F2 + x crystals. By varying the RF3 content in them, one can obtain optical media with a gradually varied refractive index n in the range 1.44–1.55, thus filling the gap in the n values between high ones for RF3 crystals and low ones for crystals of alkaline earth fluorides MF2.
371 TRITERPENES IN GRAPEFRUIT EPICUTICULAR WAX (1994)

The purpose of this study was to identify compounds in the wax of fruit obtained from different canopy positions for possible relationships to chilling injury development. Both exterior and interior canopy grapefruit wax extracts were separated by thin layer chromatography into four lipid classes: alkanes, aldehydes, linear alcohols and triterpenes. The triterpene class consisted of three subclasses: triterpenols (TOH), triterpenones (TON) and triterpenol acetates (TAC). Each triterpene subclass was analyzed by gas chromatography and their component structures estimated by comparison of retention times with authentic standards. Derivatives were prepared for each subclass: TOH were oxidized to TON, TON were reduced to TOH, and TAC hydrolyzed to TOH. Structures were verified by gas chromatography-mass spectra of components and their derivatives as well as spectra of authentic standards and their derivatives. There was a higher level of TON in interior compared with external canopy fruit. The three major TON were a amyrone, β amyrone and friedelin. α amyrone was also shown to be a major component of the wax of `Valencia' orange, a fruit not subject to chilling injury when produced in Florida
Systematic textural and geochemical variations in magnetite from a porphyry-skarn Cu (Au) system and implications for ore formation, perspective from Xinqiao Cu-Fe-Au deposit, eastern China (2022)

Magnetite is an abundant mineral in both porphyry ore and related skarn ore; the physical and chemical characteristics of magnetite in different parts of mineralized zones may allow determination of the related ore-forming processes. We present the results of detailed textural and chemical studies of magnetite from Xinqiao porphyry-skarn Cu-Au deposit, eastern China, to constrain the causative magmatic-hydrothermal processes. Five types of magnetite are identified, magmatic magnetite (type1) occurs in the causative quartz monzodiorite intrusion; re-equilibrated magmatic magnetite (type2) occurs in endoskarn; hydrothermal magnetite aggregated with hydrothermal biotite (type3a) or disseminated (type3b) and veins (type3c) occurs in the porphyry alteration zone; massive magnetite (type4) and disseminated or banded magnetite (type5) occurs in the exoskarn. Magmatic magnetite with oxy-exsolution of ilmenite lamellae indicates the magma was oxidized, and type1 magnetite that underwent hydrothermal re-equilibration (replaced by titanite and hematite) to form type2 magnetite indicates that the early magmatic-hydrothermal fluid was high temperature and highly oxidized during endoskarn formation. The Ti-rich type3a-c magnetite and the presence of ilmenite-rutile lamellae in type3c magnetite from the porphyry alteration zone demonstrate Ti mobility in the porphyry ore-forming fluid, which was high T (450 °C), oxidized and volatile-rich (hydrothermal fluorapatite; F > 3.0 wt%). Trace elements Ti, V, Sc, Co, Ni are positively correlated and decrease from type3 to type5; Mg, Mn, Zn increase in the same sequence, consistent with the temperature of fluid decreasing from porphyry to skarn mineralization, and increasing fluid-rock interaction. The elevated Sn in type5 magnetite and its coexistence with hematite in the retrograde skarn zone also indicate that the fluid remained oxidized during early skarn ore formation. Crystallization of magnetite increased the supply of reduced sulfur, which assisted formation of the Cu mineralization at Xinqiao. We highlight that magnetite textures and compositions can effectively trace the ore-forming processes in porphyry-skarn deposits, and show that porphyry related skarn magnetites are distinguishable from those in skarn Fe, skarn Cu, IOA (iron oxide-apatite) and porphyry deposits in the MLYB.
Technique for Use of Trabecular Metal Spacers in Tibiotalocalcaneal Arthrodesis With Large Bony Defects (2016)

There are many causes of large bone defects in the tibiotalar joint that need to be definitively treated with a tibiotalocalcaneal (TTC) arthrodesis. Some of the challenges of a large defect are its effect on leg length and the complications associated with trying to fill the defect with structural bone graft. We present an operative strategy involving the use of a trabecular metal implant, a TTC nail that utilized 2 forms of compression, and Reamer/Irrigator/Aspirator (RIA) autograft, to address limitations of previous operative approaches and reliably treat this operative challenge.
Quasi-elastic light scattering for intermittent dynamics (2001)

Dynamic light-scattering techniques provide noninvasive probes of diverse media such as colloidal suspensions, granular materials, and foams. Traditional analysis relies on the Gaussian properties of the scattering process found in most experimental situations and uses second-order intensity-correlation functions. This approach fails in the presence of, among other things, the collective intermittent dynamics found in systems such as granular materials. By extending the existing formalism and introducing higher-order intensity-correlation functions, we show how to detect and quantify the intrinsic dynamics and switching statistics of intermittent processes. We then explore two systems: (1) an auger-driven granular column for which the granular dynamics are controlled and the formalism is tested and (2) a granular heap whose dynamics are a priori unknown but may, now, be characterized.
An assessment of the role of dipoles on the density-of-states function of disordered molecular solids (1993)

The effect of permanent dipoles on the density-of-states (DOS) function of an array of hopping sites is examined by summing the contributions of individual dipoles to the total potential at a given site. For relative dipolar site concentrations ≳0.1, the DOS function is of Gaussian shape. At lower concentrations, it approaches a Lorentzian. Good agreement with literature data on the dipolar contribution to the DOS function for hole transport in molecularly doped polymers and molecular glasses differing with regard to dipole moment and concentration of dipolar moieties is found.
A 56-Gb/s PAM4 Receiver With Low-Overhead Techniques for Threshold and Edge-Based DFE FIR- and IIR-Tap Adaptation in 65-nm CMOS (2018)

This paper presents a four-level pulse amplitude modulation (PAM4) quarter-rate receiver that efficiently compensates for moderate channel loss in a robust manner through background adaptation of the receiver thresholds and equalization taps. The front-end utilizes an input single-stage continuous-time linear equalizer (CTLE) to boost the main cursor and relax the pre-cursor cancellation requirement, requiring only a 2-tap pre-cursor feed-forward equalizer (FFE) on the transmitter side. A 2-tap decision feedback equalizer (DFE) follows that includes one finite impulse response (FIR) tap and one infinite impulse response (IIR) tap to cancel first post-cursor and long-tail inter-symbol interference (ISI), respectively. In addition to the per-slice main three data samplers, a single error sampler is utilized for background threshold control and an edge-based sampler performs both phase-locked loop (PLL)-based clock and data recovery (CDR) phase detection and generates information for background DFE tap adaptation. Fabricated in general purpose (GP) 65-nm CMOS, the 56-Gb/s receiver achieves 4.63 mW/Gb/s and compensates for up to 20.8-dB loss at a bit error rate (BER) <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> when operated with a 2-tap FFE transmitter.
Detecting spam web pages through content analysis (2006)

In this paper, we continue our investigations of "web spam": the injection of artificially-created pages into the web in order to influence the results from search engines, to drive traffic to certain pages for fun or profit. This paper considers some previously-undescribed techniques for automatically detecting spam pages, examines the effectiveness of these techniques in isolation and when aggregated using classification algorithms. When combined, our heuristics correctly identify 2,037 (86.2%) of the 2,364 spam pages (13.8%) in our judged collection of 17,168 pages, while misidentifying 526 spam and non-spam pages (3.1%).
Formation of defect-fluorite structured NdNiOxHy epitaxial thin films via a soft chemical route from NdNiO3 precursors (2016)

A new phase of oxyhydride NdNiOxHy with a defect-fluorite structure was obtained by a soft chemical reaction of NdNiO3 epitaxial thin films on a substrate of SrTiO3 (100) with CaH2. The epitaxial relationship of this phase relative to SrTiO3 could be controlled by changing the reaction temperature. At 240 °C, NdNiOxHy grew with a [001] orientation, forming a thin layer of infinite-layer NdNiO2 at the interface between the NdNiOxHy and the substrate. Meanwhile, a high-temperature reaction at 400 °C formed [110]-oriented NdNiOxHy without NdNiO2.