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Spacecraft magnetic field measurements are able to tell us much about the planets' interior dynamics, composition, and evolutionary timeline. Magnetic fields also serve as the source for passive magnetic sounding of moons. Time‐varying magnetic fields experienced by the moons, due to relative planetary motion, interact electrically with conductive layers within these bodies (including salty subsurface oceans) to produce induced magnetic fields that are measurable by nearby, magnetometer‐equipped spacecraft. Many factors influence the character of the induced field, including the precise amplitude and phase of the time‐varying field, known as the excitation or driving field and represented by excitation moments. In this work, we present an open‐source Matlab software package named PlanetMag that features calculation of planetary magnetic field models available in the literature at arbitrary positions and times. The implemented models enable simultaneous inversion of the excitation moments across a range of oscillation frequencies using linear least‐squares methods and ephemeris data with the SPICE toolkit. Here we summarize the available magnetic field models and their associated coordinate systems. Precisely determined excitation moments are a critical input to forward models of global induced fields. Our results serve as a prerequisite to any precise comparison to spacecraft data for magnetic sounding investigation of giant planet moons—connecting the induced magnetic field to a moon's interior requires accurate representation of the oscillating excitation field. We calculate complex excitation moments relative to the J2000 epoch and share the results as ASCII tables compatible with related software packages intended for induction response calculations. Plain Language Summary: Planetary magnetic fields tell us much about a planet's interior, composition, and history. Magnetic fields are also useful for remotely probing the interior of their moons, especially for finding and characterizing potential subsurface oceans. Liquid‐water oceans within the solar system are ideal places to search for habitable environments beyond Earth. Relating spacecraft magnetic measurements to the interior properties of the moons requires an understanding of various related components, including the manner in which the magnetic field applied to the moon changes with time. We have developed an open‐source software package called PlanetMag that uses published magnetic field models to estimate the magnetic field at any point in time and space. It also has the ability to precisely estimate the planetary field oscillations at the location of each large moon in the solar system, which is needed for prediction of the magnetic field response from the moon. Calculations of these magnetic oscillations are provided in text files compatible with existing software. Key Points: We developed an open‐source software package in Matlab called PlanetMag for evaluating planet magnetic field models from the literaturePlanetMag uses ephemeris data and least‐squares inversion methods to determine amplitudes and phases of magnetic excitations for moonsComplex excitation moments are determined for all outer planet large moons in support of magnetic sounding investigations [ABSTRACT FROM AUTHOR]

Many moons in the solar system are thought to potentially harbor hidden oceans based on the features observed at their surfaces. However, the magnetic induction signatures measured in the vicinity of these moons provide the most compelling evidence for the presence of a subsurface ocean, specifically for the Jovian moons Europa and Callisto. Interpretation of these magnetic signatures can be challenging due to the various systematic and random sources of noise that are present in the magnetic field measurement. In this work, a novel magnetometric ocean detection methodology based on Principal Component Analysis is presented and shown to provide enhanced discrimination and geophysical characterization of ocean properties in the presence of noise and error sources. The proposed methodology is robust for a single‐encounter mission or an orbiting mission with multiple flybys. Here, it is applied to the Neptunian moon Triton as a prime example of an active, potential ocean world residing in the requisite time‐varying magnetic field environment that enables magnetic induction investigation of its interior. In addition to the usual noise sources, other confounding factors are addressed, including the presence of an intense conductive ionosphere, the small amplitude of Neptune's driving magnetic field, and the uncertainty of Neptune's magnetic phase at the time‐of‐arrival which can potentially hinder accurate ocean detection and characterization. The proposed methodology is applicable to any moon in the solar system residing in a time‐varying magnetic field environment. Plain Language Summary: The search for habitable oceans in the solar system motivates the need for advances in analytic techniques to positively determine the presence of subsurface oceans in challenging environments. The Principal Component Analysis (PCA) method described in this article is a new paradigm for processing space‐based magnetic field measurements for definitive detection and constrained characterization of subsurface oceans. Using Neptune's largest moon Triton as an example ocean world, PCA is directly applied to a three‐axis magnetic field data set and shown to be a powerful ocean classification tool for a single or multiple flybys, even in the presence of Triton's highly conducting ionosphere which can mask the magnetic response from the ocean. The method is able to reliably distinguish between the magnetic field signatures associated with the ocean‐plus‐ionosphere and ionosphere‐only model classes and can further determine key characteristics of the hidden ocean in the face of the confounding factors of a conductive ionosphere, local plasma current perturbations, spacecraft timing and position uncertainties, data outages, and various sources of instrument noise. The flexibility and extensibility afforded by the PCA‐based method enhance the existing and future capabilities for ocean detection and characterization at candidate ocean worlds throughout the solar system. Key Points: A novel sub‐surface ocean detection and characterization method has been developed based on Principal Component Analysis processing of magnetic induction dataEnables differentiation between ocean‐plus‐ionosphere and ionosphere‐only induction responses in the presence of various noise sourcesApplied here to the compelling target of Triton, thought to possibly harbor a sub‐surface ocean beneath a highly conducting ionosphere [ABSTRACT FROM AUTHOR]

Electrically detected magnetic resonance (EDMR) involves the electron paramagnetic resonance (EPR) study of spin dependent transport mechanisms such as spin dependent tunneling and spin dependent recombination (SDR) in solid state electronics. Conventional EPR measurements generally require strong static magnetic fields, typically 3 kG or greater, and high frequency oscillating electromagnetic fields, typically 9 GHz or higher. In this study, we directly demonstrate that, in the absence of the oscillating electromagnetic field, a very large SDR response (≈1%) can be detected at zero magnetic field with associated hyperfine interactions at extremely low magnetic fields in a silicon carbide (SiC) diode at room temperature. The zero-field SDR (ZFSDR) response that we detect is unexpected in the conventional detection scheme of SDR via EDMR. We believe that our observations provide fundamental physical understanding of other recently reported zero-field phenomena such as singlet triplet mixing in double quantum dots and low-field giant magnetoresistance in organic semiconductors. Our work provides an unambiguous demonstration that the zero-field phenomenon we observe involves SDR. Measurements reported herein indicate that extremely useful low-field SDR and ZFSDR results can be acquired simply and inexpensively in systems of technological importance. This work also suggests the potential use of this new physics in applications including absolute magnetometry with self-calibration, spin based memories, quantum computation, and inexpensive low-field EDMR spectrometers for wafer/probing stations. [ABSTRACT FROM AUTHOR]

In this study, we utilize electrically detected magnetic resonance (EDMR) techniques and electrical measurements to study defects in SiC based metal oxide semiconductor field effect transistors (MOSFETs). We compare results on a series of SiC MOSFETs prepared with significantly different processing parameters. The EDMR is detected through spin dependent recombination (SDR) in most cases. However, in some devices at a fairly high negative bias, the EDMR likely also involves spin dependent trap-assisted tunneling (SDT) between defects on both sides of the SiC/SiO2 interface. At least three different defects have been detected in the magnetic resonance measurements. The defects observed include two at the SiC/SiO2 interface or on the SiC side of the SiC/SiO2 interface: one is very likely a vacancy center with a distribution which extends into the bulk of the SiC and the other is likely a 'dangling bond' defect. A third defect, located on the SiO2 side of the SiC/SiO2 interface, has a spectrum very similar to that previously reported for an oxygen deficient silicon coupled to a hydrogen atom. In nearly all cases, we observe a strong dominating single line EDMR spectrum with an isotropic g≈2.0027. In some samples, this strong central line is accompanied by two pairs of considerably weaker side peaks which we link to hyperfine interactions with nearby Si and C atoms. The pattern is physically reasonable for a silicon vacancy in SiC. We therefore tentatively assign it to a silicon vacancy or silicon vacancy associated defect in the SiC. In one set of devices with very high interface trap density we observe another dominating spectrum with g∥=2.0026 and g⊥=2.0010 with the symmetry axis coincident with the [0001] and nearly the SiC/SiO2 interface normal. We ascribe this EDMR spectrum to a 'dangling bond' defect. A third EDMR spectrum shows up in some devices at a fairly large negative gate bias. The phase of this spectrum is quite consistently opposite to that of the SDR detected EDMR at other biases. Part of this inverted phase spectrum involves two narrow lines which are separated by ≈10.5 G. Since the center responsible for this spectrum is almost certainly in the SiO2, it is likely due to the so called 10.4 G doublet center, an unpaired electron residing on an oxygen deficient silicon atom coupled to a hydrogen in SiO2. The likely presence of one oxygen deficient silicon defect suggests that other oxygen deficient silicon atom defect sites in the oxide may also be important in SiC/SiO2 devices. Oxygen deficient silicon defects in SiO2 are typically called E′ centers. Our results collectively demonstrate considerable complexity in both the chemical composition and physical distribution of performance limiting defects in SiC transistors, with defects observed on both sides of the SiC/SiO2 interface. Our results most strongly indicate that fairly high densities of intrinsic deep-level defects, likely due to a Si vacancy or a closely related defect, extend into the bulk of the SiC in all but one of the devices prepared utilizing a fairly wide range of processing parameters. [ABSTRACT FROM AUTHOR]

We have identified a magnetic resonance spectrum associated with minority carrier lifetime killing defects in device quality 4H SiC through magnetic resonance measurements in bipolar junction transistors using spin dependent recombination (SDR). The SDR spectrum has nine distinguishable lines; it is, within experimental error, essentially isotropic with four distinguishable pairs of side peaks symmetric about the strong center line. The line shape is, within experimental error, independent of bias voltage and recombination current. The large amplitude and spacing of the inner pair of side peaks and three more widely separated pairs of side peaks are not consistent with either a simple silicon or carbon vacancy or a carbon or silicon antisite. This indicates that the lifetime killing defect is not a simple defect but a defect aggregate. The spectrum is consistent with a multidefect cluster with an electron spin S=12. (The observed spectrum has not been reported previously in the magnetic resonance literature on SiC.) A fairly strong argument can be made in terms of a first order model linking the SDR spectrum to a divacancy or possibly a vacancy/antisite pair. The SDR amplitude versus gate voltage is semiquantitatively consistent with a very simple model in which the defect is uniformly distributed within the depletion region of the base/collector junction and is also the dominating recombination center. The large relative amplitude of the SDR response is more nearly consistent with a Kaplan–Solomon–Mott-like model for spin dependent recombination than the Lepine model. [ABSTRACT FROM AUTHOR]

The quaternary zirconium alloy, Zr-3.5Sn-0.8Mo-0.8Nb, has shown promise as a possible system for utilization of transformation-induced plasticity. In this study, we investigate the effect of strain rate and stress-relaxation on the β → α phase transformation at room temperature, and present a technique to characterize the thermally-activated deformation of component phases of multi-phase alloys. The apparent activation volume of the α phase of this alloy is 13–18 b 3 , in agreement with previous studies on α -zirconium alloys, while the β phase has an apparent activation volume of 80–150 b 3 . The deformation-induced phase transformation is observed to occur more readily at lower strain rates, due to a higher strain-rate dependence than dislocation slip. This effect may lead to enhanced resistance to necking in this alloy during forming operations. • Phase transformation occurs more rapidly at lower strain rates. • Strain rate sensitivity of multiple phases is measured simultaneously and distinctly. • Macroscopic activation volume is dominated by the phase with the lowest value. • Deformation-induced phase transformation has no impact on apparent activation volume. • A novel method for measurement of strain by x-ray beam attenuation is presented. [ABSTRACT FROM AUTHOR]

Abstract The zirconium alloy Excel has been shown to retain a metastable β phase upon quenching from temperature within the α + β phase field. Using a combination of neutron diffraction and EBSD, we show that it is possible to initiate a phase transformation from β → α during tensile deformation of Excel in the quenched state. We present a model to explain the observed behaviour. EBSD results show that twin-like α laths are formed in the β grains during deformation. This β → α transformation shows a strong variant selection, as expected for a phase transformation that accommodates plastic strain. Secondary transformation laths were also observed which did not follow the expected variant rule. We present a simple model that explains quantitatively the behaviour of the β → α phase transformation during straining and accurately predicts the variant selection. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

This study investigates the retention of greater than equilibrium β phase in a two-phase zirconium alloy. We provide experimental data exploring two factors that impact the retention of β phase following heat treatment of a two-phase quaternary zirconium alloy, Zr-3.5Sn-0.8Mo-0.8Nb. Heat treatment temperature and quenching rate are varied to establish a criterion for metastable β phase retention and determine the excess free energy of the metastable phase as a function of solutionizing temperature. It is possible to retain a microstructure with up to 46 vol% β phase at room temperature in this alloy, which has a stable room temperature β phase content of 8 vol%. [ABSTRACT FROM AUTHOR]

Transmission with phase advance is experimentally evidenced in a woven metasurface made of metallic wires and dielectric yarns. Similar to the negative refraction in metamaterials, phase advance is analyzed with a retrieval procedure of effective medium parameters. It is shown that a quasi-unitary transmission level can be achieved below the magnetic plasma frequency with a phase advance in a propagation regime for which both effective permittivity and permeability exhibit negative values. By stacking two metasurfaces with metallic wires woven in orthogonal directions, the phase advance is maintained and a polarization insensitive woven metamaterial is achieved. [ABSTRACT FROM AUTHOR]

A series of in situ compression tests have been carried out at room temperature on three dual-phase Zr–2.5 wt% Nb alloys with different concentrations of the interstitial alloying elements oxygen and iron. Oxygen and iron are potent strengthening additives in two-phase alloys with a hexagonal-close packed α phase and body-centred cubic β phase, such as the Zr–Nb and Ti–V–Al systems. The evolution of interphase stress, along with the progression of twinning, were monitored during deformation by neutron diffraction. The twin volume fraction measured following deformation was not strongly dependent on ingot chemistry, contrary to previously reported results. Annealing in the α + β and the β region allowed for variation in the initial residual stress distribution and crystallographic texture, respectively, and the effect of these parameters on deformation mode selection was also investigated. Interstitial oxygen has a greater strengthening effect on prismatic 〈 a 〉 slip than on basal 〈 a 〉 slip at room temperature. High impurity contents were not observed to suppress { 10 1 ¯ 2 } 〈 10 1 ¯ 1 〉 tensile twinning. Despite being an α -stabilizer, oxygen is observed to strengthen the β phase under suitable heat treatment conditions. [ABSTRACT FROM AUTHOR]

We report on the detection of a zero-field spin dependent current response in Si based metal-oxide-semiconducting field-effect transistors. We argue that this phenomenon results from spin dependent recombination (SDR) due to the mixing of the energy levels involved in the singlet and triplet pairs which form prior to recombination involving Pb centers at the Si/SiO2 interface. We demonstrate a very strong correlation between the zero-field response, the low-field magnetic resonant response, and electrical gated current interface trap measurement. Our results provide strong evidence that previous magnetoresistance measurements made in silicon devices arise from deep level defects that cause SDR. [ABSTRACT FROM AUTHOR]

We use three electrically detected magnetic resonance (EDMR) approaches to explore nitric oxide (NO) annealing in 4H SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). One approach is sensitive to defects at the interface and those extending into the SiC. Two of these approaches are particularly sensitive to SiC/SiO2 interface defects. They show that NO anneals decrease the EDMR response. Since this and earlier studies indicate the ubiquitous presence of silicon vacancy centers in SiC MOSFETs, our results provide strong circumstantial evidence that these defects play an important role in limiting device performance and that NO anneals are effective in reducing their populations. [ABSTRACT FROM AUTHOR]

A few years back, our lab developed a signal averaging technique that greatly reduces the number of scans required to achieve a comparable signal-to-noise ratio to that of conventional signal averaging for continuous wave magnetic resonance measurements. We utilize an adaptive filter in a signal averaging scheme without any prior knowledge of the signal under observation. We termed this technique adaptive signal averaging (ASA). The technique was successful in reducing the noise variance by a factor of at least 10 in a single trace and is shown to converge in time by the same factor. ASA can also be useful in many other applications where signal averaging is utilized, such as medical imaging, electrocardiography, or electroencephalography. The purpose of this paper is to describe the advancements made to the technique, present a derivation of its performance enhancement, and illustrate the power of the technique through a set of simulations. [ABSTRACT FROM AUTHOR]

We show that electrically detected magnetic resonance (EDMR), through spin dependent trap assisted tunneling (SDTT) in amorphous SiC, exhibits approximately equal amplitudes at very high (8.5 T) and very low (0.013 T) magnetic fields at room temperature. This result strongly supports an SDTT/EDMR model in which spins at two nearby sites involved in a tunneling event are coupled for a finite time in circumstances somewhat analogous to spin pair coupling in the spin dependent recombination/EDMR model of Kaplan, Solomon, and Mott (KSM) [Kaplan, Solomon, and Mott, J. Phys. Lett. 39, 51 (1978)]. Since a comparable near zero magnetic field change in resistance is also observed in these samples, our results support the idea that this magnetoresistance response is also the result of a KSM-like mechanism involving SDTT. Additionally, we observe a large enhancement in SDTT/EDMR at high field (8.5 T) for temperatures below 50 K, which suggests the potential utility of SDTT in spin based quantum computation and other spintronic applications. [ABSTRACT FROM AUTHOR]

Excimer laser irradiation of silicone foils is shown in this work to induce decomposition, ablation and activation of such materials. Thin (100 μm) laminated silicone foils are irradiated at 248 nm as a function of impacting laser fluence and number of pulsed irradiations at 1 s intervals. Above a threshold fluence of 0.7 J/cm2, material starts decomposing. At higher fluences, this decomposition develops and gives rise to (i) swelling of the irradiated surface and then (ii) emission of matter (ablation) at a rate that is not proportioned to the number of pulses. Taking into consideration the polymer structure and the foil lamination process, these results help defining the phenomenology of silicone ablation. The polymer decomposition results in two parts: one which is organic and volatile, and another part which is inorganic and remains, forming an ever thickening screen to light penetration as the number of light pulses increases. A mathematical model is developed that accounts successfully for this physical screening effect. [Copyright &y& Elsevier]

Oxidants, generated by stimulated leukocytes, induce a variety of distinct biochemical changes in target cells. Hypochlorous acid (HOCl), produced by the action of peroxidase on hydrogen peroxide (H2O2) in the presence of chloride ions, acts at low molar concentrations (10-20 microM) to damage proteins on cell membranes and destroy their function. H2O2 rapidly permeates cells and causes inhibition of adenosine triphosphate (ATP) synthesis via both glycolytic and oxidative phosphorylation (mitochondrial) pathways. In the glycolytic pathway, damage is limited to the step involving glyceraldehyde-3-PO4 dehydrogenase (GAPDH). This results from both an attack of H2O2 on GAPDH and, indirectly, by a reduction in concentration of the GAPDH cofactor, nicotinamide adenine dinucleotide (NAD). This latter effect was found to result from activation of the enzyme, poly(adenosine diphosphate) (ADP)-ribose polymerase, an enzyme involved in deoxyribonucleic acid (DNA) repair. DNA damage in target cells was found at low concentrations of H2O2 (20-80 microM) in many cell types. Strand breaks and base hydroxylation were observed, resulting in the generation of hydroxyl radicals (.OH) from H2O2, in the presence of a transition metal. DNA damage resulted in either cell injury and death or mutations of the base sequence and amino acid residues. These latter effects led to malignant transformations in cultured cells in both tissue cultures of the cells, and in vivo in athymic mice. Exposure of a proto-oncogene, K-ras 4B, also led to the development of a malignant transformation by virtue of mutations in codon positions 12 and 61. Thus, oxidant effects on target cells can damage multiple functional pathways inside the cells, as well as give rise to malignant transformation via DNA damage. [ABSTRACT FROM AUTHOR]

The basic proteins of rat neutrophils possessing the capacity to induce vascular Permeability were analysed. Evidence indicating the presence of four such permeability proteins was presented. One of these induced the release of' histamine from rat mast cells. [ABSTRACT FROM AUTHOR]

Acute renal injury was induced immunologically with sheep antisera to rabbit glomerular basement membrane which were largely dependent on poly- morphonuclcar leucocytes (PMNs) for their pathogenic effect. This injury was characterized by the liberation of glomerular basement membrane material into the urine and a concomitant gross alteration in the permeability of the glomerular basement membrane. Selectivity of proteinuria was extremely low during PMN- mediated injury. These effects were eliminated by PMN depletion prior to the induction of experimental nephritis and were not observed when glomerular injury was induced by an antibody not significantly dependent upon PMNs. Of the known mediators of inflammation contained within PMNs, both acid proteases (cathepsins) and cationic proteins were found in the urines of rabbits with nephritis induced by a PMN-dependent antiserum. [ABSTRACT FROM AUTHOR]

The chemotactic factor, generated in whole rabbit serum following treatment with immune precipitates, was found to be principally associated with fractions containing the fifth and sixth components of complement (C'5 and C'6) after electrophoretic separation of serum. The chemotactic factor could also be generated in the intact animal, adding credence to its importance in tissue reactions induced by immunological agents. The isolated and activated C'5 and C'6 complex was found to be at least 10-20 times more active in the chemotaxis of rabbit polymorphonuclear leucocytes (PMNs) in vitro than bradykinin, kallidin, histamine, serotonin and extracts of PMN granules. The amino acid derivatives N-CBZ-glycyl-L-phenylalanine and N-CBZ-α glutamyl-L-tyrosine inhibited formation of the chemotactic factor in serum. The latter derivative also caused loss of activity of the preformed chemotactic factor in rabbit serum and in density gradient ultracentrifugation it was found that the C'5 and C'6 complex dissociated in the presence of this inhibitor. Chemotactically active C'5 to C'6 fractions, when added to the suspension of PMNs, prevented the ability of these cells to migrate toward a chemotactic source. It was also found that the ratio of combination of C'5 and C'6 was critical for the full expression of chemotactic activity. Utilizing purified components of human C', very recently obtained data indicate the requirement of the seventh component of C' (C'7) for generation of chemotactic activity. No later reacting components of C' are required. Whether C'7 is incorporated into the chemotactically active complex which sediments rapidly in the ultracentrifuge is not yet established. Similar data with guinea-pig C' complexes were also obtained. [ABSTRACT FROM AUTHOR]

A spin dependent recombination (SDR) spectrum observed in a wide range of SiC metal oxide semiconducting field effect transistors (MOSFETs) has previously been only tentatively linked to a silicon vacancy or vacancy related defect. By resolving hyperfine interactions in SDR detected spectra with 13C nuclei, we provide an extremely strong argument identifying the SDR spectrum with a silicon vacancy. Since the silicon vacancy spectrum dominates the SDR response in a wide variety of SiC MOSFETs, silicon vacancies are quite important traps in this technology. [ABSTRACT FROM AUTHOR]

The authors employ a very sensitive electrically detected electron spin resonance technique called spin dependent recombination to observe recombination centers in fully processed 4H SiC n-p-n bipolar junction transistors. Their measurements indicate that the observed dominating recombination defect in these transistors is an intrinsic center of high symmetry, most likely a vacancy. This defect likely plays a dominating role in limiting the current gain in these 4H SiC devices. [ABSTRACT FROM AUTHOR]

The authors combine metal oxide semiconductor (MOS) gated diode measurements and very sensitive electrically detected electron spin resonance measurements to detect and identify negative bias temperature instability (NBTI) generated defect centers in fully processed HfO2 pMOS field effect transistors. Both short and long term stressing defects are different from those generated by NBTI in Si/SiO2 devices. The spectra generated by long term stressing differ from the short term stressing signals and are somewhat similar to those observed in plasma nitrided oxide Si/SiO2 devices. The results suggest that NBTI defects are located in the interfacial SiO2 layer of these HfO2 devices. [ABSTRACT FROM AUTHOR]

• Synthesis and biochemical evaluation of sulfonyl piperazine LpxH inhibitors. • SAR analysis of sulfonyl piperazine LpxH inhibitors. • Report of the crystal structure of JH-LPH-41 in complex with K. pneumoniae LpxH. The UDP-2,3-diacylglucosamine pyrophosphate hydrolase LpxH is essential in lipid A biosynthesis and has emerged as a promising target for the development of novel antibiotics against multidrug-resistant Gram-negative pathogens. Recently, we reported the crystal structure of Klebsiella pneumoniae LpxH in complex with 1 (AZ1), a sulfonyl piperazine LpxH inhibitor. The analysis of the LpxH-AZ1 co-crystal structure and ligand dynamics led to the design of 2 (JH-LPH-28) and 3 (JH-LPH-33) with enhanced LpxH inhibition. In order to harness our recent findings, we prepared and evaluated a series of sulfonyl piperazine analogs with modifications in the phenyl and N -acetyl groups of 3. Herein, we describe the synthesis and structure–activity relationship of sulfonyl piperazine LpxH inhibitors. We also report the structural analysis of an extended N -acyl chain analog 27b (JH-LPH-41) in complex with K. pneumoniae LpxH, revealing that 27b reaches an untapped polar pocket near the di-manganese cluster in the active site of K. pneumoniae LpxH. We expect that our findings will provide designing principles for new LpxH inhibitors and establish important frameworks for the future development of antibiotics against multidrug-resistant Gram-negative pathogens. [ABSTRACT FROM AUTHOR]

The UDP-2,3-diacylglucosamine pyrophosphate hydrolase LpxH is an essential lipid A biosynthetic enzyme that is conserved in the majority of gram-negative bacteria. It has emerged as an attractive novel antibiotic target due to the recent discovery of an LpxH-targeting sulfonyl piperazine compound (referred to as AZ1) by AstraZeneca. However, the molecular details of AZ1 inhibition have remained unresolved, stymieing further development of this class of antibiotics. Here we report the crystal structure of Klebsiella pneumoniae LpxH in complex with AZ1. We show that AZ1 fits snugly into the L-shaped acyl chain-binding chamber of LpxH with its indoline ring situating adjacent to the active site, its sulfonyl group adopting a sharp kink, and its N-CF3-phenyl substituted piperazine group reaching out to the far side of the LpxH acyl chain-binding chamber. Intriguingly, despite the observation of a single AZ1 conformation in the crystal structure, our solution NMR investigation has revealed the presence of a second ligand conformation invisible in the crystalline state. Together, these distinct ligand conformations delineate a cryptic inhibitor envelope that expands the observed footprint of AZ1 in the LpxH-bound crystal structure and enables the design of AZ1 analogs with enhanced potency in enzymatic assays. These designed compounds display striking improvement in antibiotic activity over AZ1 against wild-type K. pneumoniae, and coadministration with outer membrane permeability enhancers profoundly sensitizes Escherichia coli to designed LpxH inhibitors. Remarkably, none of the sulfonyl piperazine compounds occupies the active site of LpxH, foretelling a straightforward path for rapid optimization of this class of antibiotics. [ABSTRACT FROM AUTHOR]

We present a feasibility study for passive sounding of Uranian icy moons using Uranian Kilometric Radio (UKR) emissions in the 100–900 kHz band. We provide a summary description of the observation geometry, the UKR characteristics, and estimate the sensitivity for an instrument analogous to the Cassini Radio Plasma Wave Science (RPWS) but with a modified receiver digitizer and signal processing chain. We show that the concept has the potential to directly and unambiguously detect cold oceans within Uranian satellites and provide strong constraints on the interior structure in the presence of warm or no oceans. As part of a geophysical payload, the concept could therefore have a key role in the detection of oceans within the Uranian satellites. The main limitation of the concept is coherence losses attributed to the extended source size of the UKR and dependence on the illumination geometry. These factors represent constraints on the tour design of a future Uranus mission in terms of flyby altitudes and encounter timing. Plain Language Summary: The large moons of Uranus are hypothesized to have subsurface oceans beneath their icy crusts. This paper analyzes the possibility to use natural radio emissions originating from Uranian auroras to probe for these oceans. Cold ice is transparent to radio waves allowing reflections from liquid water to be readily observed. Monitoring the radio noise patterns from Uranus and searching for the reflections could constitute a direct way to detect the subsurface oceans. Key Points: Passive Sounding of the Uranian moons is a promising concept and no insurmountable obstacles have been identifiedIn the presence of NH3 rich oceans, the direct detection of the ice‐ocean interface is feasibleThe method works best for the outer moons and low ocean temperatures, making it complementary to magnetic induction measurements [ABSTRACT FROM AUTHOR]

Characterizing Europa's subsurface ocean is essential for assessing Europa's habitability. The suite of instruments on the Europa Clipper spacecraft will, among others, magnetically sound Europa's interior by measuring the ocean's induced magnetic field. This magnetic field is generated in response to the Jovian time-varying magnetic environment in which Europa is immersed. However, the dynamic magnetized plasma flow of the Jovian magnetosphere creates electrical currents that give rise to magnetic perturbations near Europa. These perturbations complicate the interpretation of the induction signal, and hence the characterization and inferences on potential habitability. Thus, characterization of the ocean by magnetic sounding requires an accurate characterization of the plasma as it flows across Europa. We present the Plasma Instrument for Magnetic Sounding (PIMS), the instrument for the Europa Clipper mission that will measure the plasma contribution to the magnetic field perturbations sensed by the Europa Clipper Magnetometer. PIMS is composed of four Faraday Cup plasma spectrometers that use voltage-biased gridded apertures to dissect the space plasmas that they encounter. The instrument uses sensitive preamplifiers and processing electronics to measure the current that results when charged particles strike the instrument's metal collector plates, thus enabling a measure of the plasma characteristics near Europa to produce a more accurate magnetic sounding of Europa's subsurface ocean. PIMS consists of two sensors: one placed near the top of the Europa Clipper spacecraft and one near the bottom. Each sensor contains two Faraday Cups with a 90° full-width field-of-view. The sensors were specifically designed to withstand the Europa environment, measure both ions and electrons, and have two separate voltage ranges intended to analyze the magnetospheric and ionospheric environments, respectively. In this paper, we describe the scientific motivation for this experiment, the design considerations for the PIMS instrument, the details of the ground calibration, and other details pertinent to understanding the scientific data retrieved by PIMS. [ABSTRACT FROM AUTHOR]

Dopamine is a ubiquitous neurotransmitter essential in the proper functioning of the human body. In addition to this critical role, the catecholamine core has shown utility as a scaffold for numerous drugs and in other applications, like metal detection and adhesive materials. Substituents at the 6-position of dopamine’s catechol core can modulate its stereoelectronic properties, the acidity of its phenolic hydroxyl groups, and the overall hydrophobicity of the molecule. Herein, we report the synthesis of a series of four novel dopamine analogues substituted at the 6-position of catechol core. The1H NMR chemical shift of the aromatic protonmetato the substituent correlated strongly with the Hammettσmconstant, confirming the electronic properties of substituents. [ABSTRACT FROM AUTHOR]

In June 2020, observations of anthropogenic radionuclides in Estonia, Finland, and Sweden that were not related to any acknowledged environmental release led to a comprehensive investigation on the source and cause of the unusual emissions. Several of the observed radionuclides were on the list of Comprehensive Nuclear-Test-Ban Treaty (CTBT) relevant radionuclides as an indicator of a potential nuclear test, and warranted detailed investigation. While analysis of aerosol samples coupled with Atmospheric Transport and Dispersion Modelling (ATDM) is a standard approach for environmental particulate releases, several new techniques were employed to better characterize the samples that allowed for useful inferences to be made. These inferences were crucial in forming the ultimate hypothesis for determining the facility type and location of the release. • Unattributed anthropogenic radionuclides observed in the Baltic region in 2020. • Coincident spectroscopy and sample characterization help identify source facility. • Combination of tools allows characterizes release to aid with CTBT verification. [ABSTRACT FROM AUTHOR]

Modeling of the electrical conductivity (EC) of icy moon oceans has previously assumed that chloride, sulfate, and other ions released from rock leaching are the main solutes and carriers of EC. Here, we show that accreted volatiles, such as carbon dioxide and ammonia, can add a significant fraction of solutes in bodies whose volatile content was in part supplied from cometary materials. These volatiles can increase the EC of aqueous solutions above 1 S/m. Our salinity and EC estimates can serve as a basis for planning future magnetometer investigations at icy moons and dwarf planets. In particular, oceans expected in some of the Uranian satellites and Neptune's satellite Triton could have EC above 3 S/m as a result of accretion of both carbon dioxide and ammonia, even if rock leaching during water‐rock separation was limited, and if chlorine and sulfur abundances may be at CI carbonaceous chondritic levels. Plain Language Summary: Searching for deep oceans in icy bodies is a major driver of planetary exploration. Magnetometry is used to detect electric currents in deep oceans generated by a varying magnetic field, from a giant planet or solar wind, as was done at Jupiter's moon Europa during the Galileo mission. Previous studies have assumed that the salinity of deep oceans is determined by the leaching of major elements from accreted rock, which may yield brackish and low electrical conductivity solutions. We show that carbon dioxide, an abundant ice in the outer solar system, could contribute a significant fraction of solutes (carbonate and bicarbonate ions) in ocean worlds, regulated in particular by the presence of ammonia. The latest solar system dynamical models predict that dwarf planets and most icy moons accreted ices rich in carbon dioxide and ammonia. If oceans exist today inside these bodies, the resulting ion concentrations would produce a stronger magnetic signature than previously expected, perhaps detectable by future spacecraft missions. Key Points: Accreted CO2 and NH3 ices can significantly increase the salinity and electrical conductivity (EC) of deep oceansWater to rock ratio and ammonia abundance drive the concentrations of carbonate and bicarbonate ions in solutionPredicted EC estimates can be used to plan future ocean search missions at icy moons and dwarf planets [ABSTRACT FROM AUTHOR]

Franz diffusion cells containing uniformly dehydrated equine blood clots to simulate fibrinous eschar were used to measure the rate of debridement of fibrin by novel and traditional wound dressings, under standardised conditions of temperature, pH and humidity. Significant increases in protein breakdown occurred within 24 hours with all the dressings, but not thereafter. In general, dressings hydrated in normal saline were better as debriding agents than dressings hydrated in water. Autolytic debriding agents were 47 per cent more effective than chemical debriding agents; specifically, hydrofibre and gauze dressings hydrated in saline broke down more than 3500 µg/mI of protein whereas dressings impregnated with proteolytic enzymatic agents digested less than 1400 µg/mI. [ABSTRACT FROM AUTHOR]

Back end of line dielectrics with low dielectric constants are needed for current and future integrated circuit technology. However, an understanding of the defects that cause leakage currents and limit reliability in these films is not yet developed. We utilize conventional electron paramagnetic resonance (EPR), electrically detected magnetic resonance (EDMR), and leakage current measurements, complimented by Fourier transform infrared spectroscopy and Rutherford back scattering results, to investigate a-SiC:H dielectrics which have great potential use for back end of line dielectrics. We observe a strong correlation between conventional EPR defect density measurements and leakage currents. There is also a very strong correlation between hydrogen content and both leakage current and EPR defect density. The close correspondence between the EPR results and the leakage currents strongly indicates that the defects observed by EPR are largely responsible for the leakage currents and likely limit the dielectric reliability. Important reliability phenomena in these films are time-dependent dielectric breakdown and stress induced leakage current. Additionally, we have utilized EDMR via spin dependent trap assisted tunneling to investigate the direct link between defects observed in EPR and electrical transport. [ABSTRACT FROM AUTHOR]

Pastoral farming is the dominant land use in New Zealand today and is under considerable domestic social and political pressure to reduce its environmental footprint. In this article, we explore options to enhance native biodiversity conservation within New Zealand pastoral systems. We argue that there is strong synergistic interdependence between biodiversity conservation and pastoral farming and suggest that it is possible to have win-win outcomes for both. Landowners need to be incentivised and rewarded for good biodiversity management, rather than relying on a strict rules-based approach. To bring integrity and objective support to this incentive-based approach, farmers need to adopt environmental management planning that is supported by good biodiversity extension resources. Alongside this, a verification system is required that shows farmers are doing what they say they are doing and reflects agreed management targets for biodiversity. This approach requires trust and partnership among all players in agroecosystems - farmers, government, food and fibre processors, scientists, conservationists, NGOs, and the wider New Zealand population. We suggest that if we change the way we think about how farming and biodiversity interact, then we will achieve substantial biodiversity gains across the 50% of New Zealand under pastoral farming. This then brings integrity to the existing and expanding market story for pastoral farming and creates a stronger connection between all New Zealanders and the farming sector. Advancing our thinking in this way will enable New Zealand to maintain a premium for our farming products internationally while supporting conservation of our native biodiversity. [ABSTRACT FROM AUTHOR]

Uranium ore concentrate (UOC) is an important nuclear material of interest for Canada. A large scale analytical program is being led by the Directorate of Security and Safeguards (DSS) of the Canadian Nuclear Safety Commission (CNSC) to establish a reference dataset of UOCs that have passed through and/or are currently under Canadian regulatory control. Isotopic ratios are among the signatures being captured under the reference dataset. Accelerator Mass Spectrometry (AMS) has been used for the measurement and assessment of 236U/238U and 187Os/188Os, respectively. Furthermore, since UOCs have uranium typically concentrated to ≥70% by weight, a direct-AMS assay method is possible wherein the samples can be measured without time consuming chemical digestion and processing. Using this direct-AMS approach, several related ratios (231Pa/238U, 230Th/238U, 226Ra/238U) were also assessed within the data acquisition sequence used for measuring the 236U/238U ratios, and 185Re, 187Re and 187Os, 188Os, 191Ir and 193Ir in the sequence for the 187Os/188Os ratios. The sum of these results can be shown together in a "bar-code" pattern to strengthen the capability for UOC source identification. Unexpectedly large 236U/238U ratios (up to ≥1 × 10−7) have been found in several UOC samples. The 187Os/188Os ratio has also been shown for the first time to be a viable supplementary signature of UOCs. This work shows that the direct-AMS method has the potential to become an effective tool for nuclear forensics provenance assessment applications with UOCs. The implications of the results, and the need for further refinement of the sputter target preparation, as well as the Cs+ sputter ion source itself, are also discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Five catechol nitrile derivatives were designed, synthesized (46–93%) and fully characterized. • An in vitro assay was used to determine the catechol nitrile and seven 6-substituted dopamine derivatives' ability to inhibit COMT. • The results of the inhibition assay were supported by pKa determination and molecular docking of the nitriles and the dopamine derivatives. • The importance of both the neutral tail and an electron withdrawing substituent for strong inhibition of COMT was confirmed. l -DOPA, a dopamine precursor, is commonly used as a treatment for patients with conditions such as Parkinson's disease. This therapeutic l -DOPA, as well as the dopamine derived from l -DOPA, can be deactivated via metabolism by catechol- O -methyltransferase (COMT). Targeted inhibition of COMT prolongs the effectiveness of l -DOPA and dopamine, resulting in a net increase in pharmacological efficiency of the treatment strategy. Following the completion of a previous ab initio computational analysis of 6-substituted dopamine derivatives, several novel catecholic ligands with a previously unexplored neutral tail functionality were synthesized in good yields and their structures were confirmed. The ability of the catecholic nitriles and 6-substituted dopamine analogues to inhibit COMT was tested. The nitrile derivatives inhibited COMT most effectively, in agreement with our previous computational work. pKa values were used to further examine the factors involved with the inhibition and molecular docking studies were performed to support the ab initio and experimental work. The nitrile derivatives with a nitro substituent show the most promise as inhibitors, confirming that both the neutral tail and the electron withdrawing group are essential on this class of inhibitors. [ABSTRACT FROM AUTHOR]

A split ring resonator (SRR) antenna integrated in textile by embroidery is reported. The antenna was designed and produced by targeting two goals. First, a size reduction of the antenna was achieved by means of an SRR. Secondly, the connection loss was reduced by using a copper wire dipole fixed by embroidery. On the basis of numerical simulations, three operating modes are evidenced depending on the individual resonance frequency either of the dipole or resonator‐related. Especially, a balanced mode is confirmed by experiments with two resonances measured at 1.8 and 2.2 GHz with a return loss greater than 31 dB. Finally, the textile antenna exhibits a radiation pattern similar to the radiation pattern of a dipole antenna. [ABSTRACT FROM AUTHOR]

The European Venus Explorer (EVE) mission was proposed to the European Space Agency in 2007, as an M-class mission under the Cosmic Vision Programme. Although it has not been chosen in the 2007 selection round for programmatic reasons, the EVE mission may serve as a useful reference point for future missions, so it is described here. It consists of one balloon platform floating at an altitude of 50–60 km, one descent probe provided by Russia, and an orbiter with a polar orbit which will relay data from the balloon and descent probe, and perform science observations. The balloon type preferred for scientific goals is one which oscillates in altitude through the cloud deck. To achieve this flight profile, the balloon envelope contains a phase change fluid, which results in a flight profile which oscillates in height. The nominal balloon lifetime is 7 days—enough for one full circumnavigation of the planet. The descent probe’s fall through the atmosphere takes 60 min, followed by 30 min of operation on the surface. The key measurement objectives of EVE are: (1) in situ measurement from the balloon of noble gas abundances and stable isotope ratios, to study the record of the evolution of Venus; (2) in situ balloon-borne measurement of cloud particle and gas composition, and their spatial variation, to understand the complex cloud-level chemistry; (3) in situ measurements of environmental parameters and winds (from tracking of the balloon) for one rotation around the planet, to understand atmospheric dynamics and radiative balance in this crucial region. The portfolio of key measurements is complemented by the Russian descent probe, which enables the investigation of the deep atmosphere and surface. [ABSTRACT FROM AUTHOR]

Background Anti-TNF agents are now widely used in Crohn’s disease (CD), and in ulcerative colitis (UC). Aim To review the safety profile of anti-TNF agents in all patients treated with infliximab in Edinburgh from 1999 to 2007. Methods Complete data were available on 202/207 patients comprising 157 CD, 42 UC and three coeliac disease. Median follow-up was 2.4 years (1.0–4.9) with a total of 620 patient-years follow-up. About 19.1% of CD patients were subsequently treated with adalimumab. Results Seven deaths (3.3%) occurred in follow-up; only one death was <1 year post-infliximab (at day 72, from lung cancer). A total of six malignancies (three haematological, three bronchogenic) and six cases of suspected demyelination (three with confirmed neurological disease) were reported. In the 90 days following infliximab, 95 adverse events (36 serious) occurred in 58/202 (28.7%) patients. In all, 42/202 (20.8%) had an infectious event (22 serious) and 27/202 (13.4%) of patients had an infusion reaction: 19 acute (four serious) and eight delayed (three serious). Conclusions Serious infections, malignancies and neurological disease complicate anti-TNF use in clinical practice. Although evidence for causality is unclear, potential mechanisms and predisposing factors need to be explored. In individual patients, the risk/benefit analysis needs to be carefully assessed and discussed prior to commencement of therapy. [ABSTRACT FROM AUTHOR]

Studies assessing withdrawal phenomenon during short-term abstinence from chronic cocaine use have been limited. Although cocaine abusers are reported to be at increased risk for cardiac disorders, little research has assessed cardiac parameters in cocaine abusers and subsequent changes in these parameters that may be associated with the discontinuation of cocaine use. In this study, we categorize 441 chronic cocaine abusers into three groups based on self-reported length of abstinence from cocaine use at entry into a trial approved by the National Institute on Drug Abuse (NIDA) assessing the use of pergolide mesylate in treating relapse and craving in crack cocaine abuse. Electrocardiogram (ECG) PR intervals were found to be correlated positively with length of abstinence, returning to normal population levels within 30 days. In addition, levels of generalized anxiety, nervousness, and heart racing were found to be correlated negatively with length of abstinence from crack cocaine. This work provides preliminary evidence of cardiac and mood-related parameters that are associated with cocaine abstinence and that may indicate specific withdrawal phenomena in chronic users. In addition, these results suggest that the risk of cardiomyopathies associated with abnormal atrial-ventricular polarization may dissipate relatively quickly in abusing individuals. [ABSTRACT FROM AUTHOR]

A split ring resonator (SRR) antenna integrated in textile by embroidery is reported. The antenna was designed and produced by targeting two goals. First, a size reduction of the antenna was achieved by means of an SRR. Secondly, the connection loss was reduced by using a copper wire dipole fixed by embroidery. On the basis of numerical simulations, three operating modes are evidenced depending on the individual resonance frequency either of the dipole or resonatorrelated. Especially, a balanced mode is confirmed by experiments with two resonances measured at 1.8 and 2.2 GHz with a return loss greater than 31 dB. Finally, the textile antenna exhibits a radiation pattern similar to the radiation pattern of a dipole antenna. [ABSTRACT FROM AUTHOR]