gebhart/patrepeval huggingface dataset:
Correction for scatter in 99mTc imaging for a CZT-based cardiac SPECT scanner (2012)

2239 Objectives 99mTc labelled compounds are frequently used in evaluation of cardiac perfusion and function. A contributing factor to degradation of image quality is scatter. Traditional window-based scatter subtraction methods are unsuitable for CZT detectors as energy windows below the photopeak include ‘spill-down’ counts due to incomplete charge collection. The method investigated applies iterative deconvolution of projection images, correcting for scatter in presence of spill-down. Methods Experimental measurements were performed on the D-SPECT camera (Spectrum Dynamics, Israel) with pixelated CZT detectors. A source in air was used to estimate spill-down from the photopeak window (WP, 133-148keV) to a lower window (WL, 105-130keV). Monte Carlo (MC) simulations were used to obtain convolution parameters relating the scatter distribution in WP to that in WL. An MLEM-algorithm was used to iteratively estimate scatter and primary components of WP, using the calculated parameters to estimate scatter and spill-down from WP to WL. The method was evaluated using an experimentally measured thorax phantom with a 99mTc -filled cardiac insert. The phantom was also simulated using MC. The ratio between the total counts in WL (TWL) and total counts in WP (TWP) was calculated, representing the scatter fraction estimated with a simple window based method. This was compared to the ratio between estimated scatter counts in WL (SWL) and TWP for both corrected experimental data and simulated data. Results The experimental TWL-to-TWP ratio was 0.93 for the uncorrected images. Results show that the SWL-to-TWP ratio was 0.53 calculated using MC (the ‘true’ ratio) and 0.64 for the corrected experimental data. This shows that a window-based scatter subtraction method would over-estimate scatter in WL significantly. The estimated scatter fraction in WL improves after correction with our new method. Conclusions Promising results show that iteratively estimating scattered counts in images is a more accurate method than window-based subtraction methods for imaging on a CZT-based scanner
The halogen bond: a new avenue in recognition and self-assembly (2018)

Welcome to this themed issue of <italic>NJC</italic> entitled: ‘The halogen bond: a new avenue in recognition and self-assembly’.
Insect Seminal Fluid Proteins: Identification and Function (2010)

Seminal fluid proteins (SFPs) produced in reproductive tract tissues of male insects and transferred to females during mating induce numerous physiological and behavioral postmating changes in females. These changes include decreasing receptivity to remating; affecting sperm storage parameters; increasing egg production; and modulating sperm competition, feeding behaviors, and mating plug formation. In addition, SFPs also have antimicrobial functions and induce expression of antimicrobial peptides in at least some insects. Here, we review recent identification of insect SFPs and discuss the multiple roles these proteins play in the postmating processes of female insects.
Sparsity-based frequency-hopping spectrum estimation with missing samples (2016)

In this paper, we address the problem of spectrum estimation of frequency-hopping (FH) signals in the presence of random missing samples. The signals are analyzed within the bilinear time-frequency representation framework, where a time-frequency kernel is designed based on inherent FH signal structures. The designed kernel permits effective suppression of cross-terms and artifacts due to missing samples while preserving the FH signal auto-terms. The kernelled results are represented in the instantaneous autocorrelation function domain, which are then processed using sparse reconstruction methods for high-resolution estimation of the FH signal time-frequency spectrum. The proposed method achieves accurate FH signal spectrum estimation even when a large proportion of data samples is missing. Simulation results verify the effectiveness of the proposed method and its superiority over existing techniques.
Optical homodyne tomography of information carrying laser beams (1998)

Optical homodyne tomography (OHT) is a tool that allows the reconstruction of Wigner functions for each detection frequency of a propagating optical beam. It can measure probability distribution functions (PDF's) of the field amplitude for any given quadrature of interest. We demonstrate OHT for a range of classical optical states with constant and time varying modulations and show the advantage of OHT over conventional homodyne detection. The OHT simultaneously determines the signal to noise ratio in both amplitude and phase quadratures. We show that highly non-Gaussian Wigner functions can be obtained from incoherent superpositions of optical states.
Mesoscopic analyses of the impact of morphology and operating conditions on the transport resistances in a proton-exchange-membrane fuel-cell catalyst layer (2020)

Exploring the origins of local transport resistance and characterizing the oxygen transport resistances in the catalyst layer (<italic>R</italic><sub>CL</sub>) are critical for cost reduction.
Dopamine is involved in selectivity of dopaminergic neuronal death by rotenone (2003)

Mitochondrial complex I activity is partially suppressed in patients with Parkinson's disease, which is characterized by dopaminergic neuronal death. However, the precise relationship between neuronal death and mitochondrial complex I suppression has been unresolved. We investigated the involvement of superoxide and endogenous dopamine in neurotoxicity by rotenone, a complex I inhibitor. A short exposure to rotenone at high concentrations reduced the viability of both dopaminergic and non-dopaminergic neurons. The toxicity was significantly prevented by a membrane-permeable superoxide dismutase mimetic and alpha-methyl-p-tyrosine (alpha-MT), a tyrosine hydroxylase inhibitor. Chronic treatment with low-concentration rotenone caused selective toxicity to dopaminergic neurons, and this toxicity was attenuated by alpha-MT. These data suggest that superoxide and endogenous dopamine play an important role in dopaminergic neuronal loss.
Consistency tests for key comparison data (2004)

Results of International Key Comparisons of National Measurement Standards provide the technical basis for the Mutual Recognition Arrangement (MRA) formulated by Le Comité International des Poids et Mesures (CIPM). With many key comparisons already completed and a number of new key comparison experiments currently under way, we now have a better understanding of the statistical issues that need to be addressed for successfully analysing data from key comparisons and making proper interpretations of the results. There is clearly a need for a systematic approach to statistical analyses of key comparison data that can be implemented routinely by all participating laboratories.
Generation of Low-Frequency Rayleigh Waves by Heavy Lorries (1995)

Generation of low-frequency ground vibrations by heavy lorries is considered theoretically for both vehicles accelerating (decelerating) with a constant acceleration and vehicles travelling at constant speed on damaged or bumpy surfaces. In the case of damaged or bumpy surfaces, excitation of axle-hop resonances is taken into account, whereas an accelerating or braking vehicle is modelled as a point horizontal traction force applied to the ground and moving along with the vehicle. Frequency spectra of the vertical component of the ground vibration velocity are investigated for different functions of road surface roughness, acceleration, final (initial) speed of the vehicle, ground attenuation, Poisson's ratio, and radiation angle relative to the direction of the vehicle movement. It is shown that damaged or bumpy road surfaces normally generate vibrations of higher amplitudes, in comparison with accelerating and braking lorries. In contrast to vehicles travelling along bumpy or uneven roads and generating vibrations propagating at all directions, the ground vibrations generated by accelerating and braking vehicles are characterised by the directivity function showing that there is no radiation in the direction perpendicular to the vehicle movement.
Delay-Reduced Mode of MPEG-4 Enhanced Low Delay AAC (AAC-ELD) (2016)

S.536-543
Identification of lactate dehydrogenase as a mammalian pyrroloquinoline quinone (PQQ)-binding protein (2016)

Pyrroloquinoline quinone (PQQ), a redox-active o-quinone, is an important nutrient involved in numerous physiological and biochemical processes in mammals. Despite such beneficial functions, the underlying molecular mechanisms remain to be established. In the present study, using PQQ-immobilized Sepharose beads as a probe, we examined the presence of protein(s) that are capable of binding PQQ in mouse NIH/3T3 fibroblasts and identified five cellular proteins, including l-lactate dehydrogenase (LDH) A chain, as potential mammalian PQQ-binding proteins. In vitro studies using a purified rabbit muscle LDH show that PQQ inhibits the formation of lactate from pyruvate in the presence of NADH (forward reaction), whereas it enhances the conversion of lactate to pyruvate in the presence of NAD(+) (reverse reaction). The molecular mechanism underlying PQQ-mediated regulation of LDH activity is attributed to the oxidation of NADH to NAD(+) by PQQ. Indeed, the PQQ-bound LDH oxidizes NADH, generating NAD(+), and significantly catalyzes the conversion of lactate to pyruvate. Furthermore, PQQ attenuates cellular lactate release and increases intracellular ATP levels in the NIH/3T3 fibroblasts. Our results suggest that PQQ, modulating LDH activity to facilitate pyruvate formation through its redox-cycling activity, may be involved in the enhanced energy production via mitochondrial TCA cycle and oxidative phosphorylation.
Hyaluronan Benzyl Ester as a Scaffold for Tissue Engineering (2009)

Tissue engineering is a multidisciplinary field focused on in vitro reconstruction of mammalian tissues. In order to allow a similar three-dimensional organization of in vitro cultured cells, biocompatible scaffolds are needed. This need has provided immense momentum for research on "smart scaffolds" for use in cell culture. One of the most promising materials for tissue engineering and regenerative medicine is a hyaluronan derivative: a benzyl ester of hyaluronan (HYAFF). HYAFF can be processed to obtain several types of devices such as tubes, membranes, non-woven fabrics, gauzes, and sponges. All these scaffolds are highly biocompatible. In the human body they do not elicit any adverse reactions and are resorbed by the host tissues. Human hepatocytes, dermal fibroblasts and keratinocytes, chondrocytes, Schwann cells, bone marrow derived mesenchymal stem cells and adipose tissue derived mesenchymal stem cells have been successfully cultured in these meshes. The same scaffolds, in tube meshes, has been applied for vascular tissue engineering that has emerged as a promising technology for the design of an ideal, responsive, living conduit with properties similar to that of native tissue.
Smart Polymer Nanoparticles Designed for Environmentally Compliant Coatings (2011)

We describe the synthesis, characterization, and film-forming properties of two-component nanoparticles that undergo a reversible morphology transformation in water as a function of pH. The particles consist of a high molecular weight acrylate copolymer and an acid-rich oligomer designed to be miscible with the polymer when its -COOH groups are protonated. Attaching a fluorescence resonance energy transfer (FRET) pair to components inside the nanoparticles enabled us to assess morphology at the molecular level. By inspecting changes in the donor fluorescence decay profile at different pH values, we established miscibility of the components in acidic solution but with charge-induced phase separation when the oligomers were neutralized to their carboxylate form. Complementary titration experiments revealed that the nanoparticles adopt a core-shell structure when the acid groups are deprotonated. We studied the effect of the acid-rich oligomer on the diffusion rate of the high molecular weight polymers following film formation. Our results show that the carboxylated oligomer enhanced the rate of diffusive mixing between high molecular weight molecules by more than 2 orders of magnitude. FRET measurements carried out on partially dried films using a low-resolution microscope showed that the carboxylate oligomer shell can delay coalescence for ca. 30 min after passage of the drying front. This delay is expected to help with increasing the 'open time' of latex paints, a desirable property of solvent-based paints that remains difficult to achieve with (environmentally compliant) waterborne paints. Use of ammonia as a volatile base resulted in synergistic effects: initial retardation of coalescence followed by acceleration of diffusive mixing as the ammonium salts dissociated and ammonia evaporated from the film.
Introducing Defects in 3D Photonic Crystals: State of the Art (2006)

Abstract 3D photonic crystals (PhCs) and photonic bandgap (PBG) materials have attracted considerable scientific and technological interest. In order to provide functionality to PhCs, the introduction of controlled defects is necessary; the importance of defects in PhCs is comparable to that of dopants in semiconductors. Over the past few years, significant advances have been achieved through a diverse set of fabrication techniques. While for some routes to 3D PhCs, such as conventional lithography, the incorporation of defects is relatively straightforward; other methods, for example, self‐assembly of colloidal crystals (CCs) or holography, require new external methods for defect incorporation. In this review, we will cover the state of the art in the design and fabrication of defects within 3D PhCs. The figure displays a fluorescence laser scanning confocal microscopy image of a y‐splitter defect formed through two‐photon polymerization within a CC.
Using an annealing genetic algorithm to solve global energy minimization problem in molecular binding (2002)

Molecular binding, important in drug design, explores the accurate binding structures between molecules. This exploration can be formulated as a global optimization problem. However, the problem in molecular binding is that the search space is very large and the computational cost increases tremendously with the growth of the degrees of freedom. In this paper, we utilize a new algorithm called the annealing genetic algorithm to solve the global optimization problem in molecular binding. Using a protein with three anti-cancer drugs in our model, our algorithm can find a binding structure with a complicated energy computation within a couple of hours and the experimental results indicate that the solutions are reasonable.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>
High-Thermal-Conductivity Fabrics (2012)

Heat management with common textiles such as nylon and spandex is hindered by the poor thermal conductivity from the skin surface to cooling surfaces. This innovation showed marked improvement in thermal conductivity of the individual fibers and tubing, as well as components assembled from them. The problem is centered on improving the heat removal of the liquid-cooled ventilation garments (LCVGs) used by astronauts. The current design uses an extensive network of water-cooling tubes that introduces bulkiness and discomfort, and increases fatigue. Range of motion and ease of movement are affected as well. The current technology is the same as developed during the Apollo program of the 1960s. Tubing material is hand-threaded through a spandex/nylon mesh layer, in a series of loops throughout the torso and limbs such that there is close, form-fitting contact with the user. Usually, there is a nylon liner layer to improve comfort. Circulating water is chilled by an external heat exchanger (sublimator). The purpose of this innovation is to produce new LCVG components with improved thermal conductivity. This was addressed using nanocomposite engineering incorporating high-thermalconductivity nanoscale fillers in the fabric and tubing components. Specifically, carbon nanotubes were added using normal processing methods such as thermoplastic melt mixing (compounding twin screw extruder) and downstream processing (fiber spinning, tubing extrusion). Fibers were produced as yarns and woven into fabric cloths. The application of isotropic nanofillers can be modeled using a modified Nielsen Model for conductive fillers in a matrix based on Einstein s viscosity model. This is a drop-in technology with no additional equipment needed. The loading is limited by the ability to maintain adequate dispersion. Undispersed materials will plug filtering screens in processing equipment. Generally, the viscosity increases were acceptable, and allowed the filled polymers to still be processed.The novel feature is that fabrics do not inherently possess good thermal conductivity. In fact, fabrics are used for thermal insulation, not heat removal. The technology represents the first material that is a wearable fabric, based on company textiles and materials that will significantly conduct heat.
Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries (2018)

The performance of electrode materials in lithium-ion (Li-ion), sodium-ion (Na-ion) and related batteries depends not only on their chemical composition but also on their microstructure. The choice of a synthesis method is therefore of paramount importance. Amongst the wide variety of synthesis or shaping routes reported for an ever-increasing panel of compositions, spray-drying stands out as a versatile tool offering demonstrated potential for up-scaling to industrial quantities. In this review, we provide an overview of the rapidly increasing literature including both spray-drying of solutions and spray-drying of suspensions. We focus, in particular, on the chemical aspects of the formulation of the solution/suspension to be spray-dried. We also consider the post-processing of the spray-dried precursors and the resulting morphologies of granules. The review references more than 300 publications in tables where entries are listed based on final compound composition, starting materials, sources of carbon etc.
Long‐Lived Efficient Inverted Organic Light‐Emitting Diodes Developed by Controlling Carrier Injection Barrier into Emitting Layer (2020)

Abstract Inverted organic light‐emitting diodes (iOLEDs), where electrons are injected without the use of reactive metals such as alkali metals, have attracted extensive attention owing to their higher air stability than conventional OLEDs (cOLEDs). Although iOLEDs are promising for use in applications such as flexible displays, little is known about the emitting layer most suitable for improving their operational lifetime, which is one of the most important parameters for practical applications. Here, it is shown that the operational lifetimes of both iOLEDs and cOLEDs strongly depend on the hole and electron injection barriers of the emitting layer, which is clarified by synthesizing novel emitting hosts having similar molecular structures but different energy levels. The cOLED employing the novel emitting host with the largest hole injection barrier exhibits the shortest operational lifetime, whereas the iOLED employing the same emitting host exhibits the longest operational lifetime owing to the smallest electron injection barrier. The appropriate energy levels of the emitting layer can differ between iOLEDs and cOLEDs since the management conditions of the carriers, excitons, and polarons in iOLEDs are different from those in cOLEDs. A green iOLED with performance equivalent to that of state‐of‐the‐art green cOLEDs reported in the literature is first realized.
Distributed optimal control of a nonstandard system of phase field equations : dedicated to Prof. Dr. Ingo Müller on the occasion of his 75th birthday (2011)

We investigate a distributed optimal control problem for a phase field model of Cahn-Hilliard type. The model describes two-species phase segregation on an atomic lattice under the presence of diffusion; it has been introduced recently in [4], on the basis of the theory developed in [15], and consists of a system of two highly nonlinearly coupled PDEs. For this reason, standard arguments of optimal control theory do not apply directly, although the control constraints and the cost functional are of standard type. We show that the problem admits a solution, and we derive the first-order necessary conditions of optimality.
The temporal organisation of the feeding behaviour of four species of wallaby: examining chronobiological and homeostatic influences (2005)

We studied the temporal distribution of feeding events of tammar wallabies, parma wallabies, brush-tailed rock-wallabies and swamp wallabies by infrared video-recording of captive animals maintained in a 12 : 12 light : dark cycle with constant temperature, and by radio-microphone surveillance of free-ranging animals on Kawau Island, New Zealand. Analyses of mean time spent feeding per 20-min period for tammar and parma wallabies showed significant circadian variation in both captive and free-ranging animals but not in captive or free-ranging brush-tailed rock wallabies or swamp wallabies. While there was no significant difference in the extent of circadian variation of feeding rate between tammar and parma wallabies there were significant differences according to the type of food being fed. Thus, circadian variation in feeding rate was greater in both species when standing sward was fed. None of the survivorship curves of the interfeed intervals of either captive or free-ranging animals showed a discontinuity suggestive of organisation of feed events into meals. There were bicrepuscular peaks of feed-event density in both captive and free-ranging tammar and parma wallabies. There was a similar bicrepuscular distribution of feed-event density in free-ranging brush-tailed rock-wallabies but a more uniform temporal distribution of this parameter in captive specimens. There was a more uniform circadian distribution of feed-event density in a single captive and a single free-ranging swamp wallaby. Thus the circadian incidence of the feeding events of tammar and parma wallabies were more resistant to changes in the incidence of stochastic environmental variables such as predation whereas those of bush-tailed rock-wallabies and swamp wallabies were more susceptible to changes in these stimuli.
<title>Length-minimization design considerations in photonic integrated circuits incorporating directional couplers</title> (1991)

Because directional couplers involve channel waveguides which are very close to one another, transition regions to regions where channel waveguides are widely separated are utilized. The total length of a directional coupler and transition regions can be minimized for a particular degree of field confinement. Calculations presented for LiNbO3-, GaAlAs-, and SiO2/Si-based optical channel waveguides demonstrate the presence of a minimum total length corresponding to a particular degree of field confinement. The overall length at the minimum is shown to be significantly lower than for other values of field confinement allowing single-mode operation. This implies that either more devices can be integrated on a substrate or that less material is needed for an integrated optical circuit.