Experimental study of endurance characteristics of Al-doped HfO2ferroelectric capacitor

In this work, the endurance characteristics of Al-doped HfO₂(HAO)-based metal-ferroelectric-metal (MFM) capacitors (which were annealed at 1000 °C) with various doping concentrations were investigated. The doping concentration was optimized for the high annealing temperature (1000 °C) process. To investigate the impact of cycling pulses on the endurance characteristics of HAO-based MFM capacitor, the rise/fall time (t_r/f) and hold time (t_h) for the cycling pulses were varied. Moreover, by adopting the recoverable fatigue process, the endurance characteristics under repetitive wake-up/fatigue processes were studied. The HAO capacitors achieved the remnant polarization (2P_r) of 23.767μC cm^-2at pristine state under the high annealing temperature. Furthermore, it was demonstrated that the endurance characteristics (∼10⁸cycles) of the HAO capacitors were comparable to them of other HfO₂-based ferroelectric capacitors. Lastly but not least, it turned out that the amount of oxygen and oxygen vacancies in the HAO thin film was dependent of doping concentrations for the film. The impact of oxygen and oxygen vacancies was quantitatively analyzed, in detail, with TEM, XPS and GIXRD analysis.

Diversity of the Hydroxylamine Oxidoreductase (HAO) Gene and Its Enzyme Active Site in Agricultural Field Soils

Nitrification is a key process in the biogeochemical nitrogen cycle and a major emission source of the greenhouse gas nitrous oxide (N2O). The periplasmic enzyme hydroxylamine oxidoreductase (HAO) is involved in the oxidation of hydroxylamine to nitric oxide in the second step of nitrification, producing N2O as a byproduct. Its three-dimensional structure demonstrates that slight differences in HAO active site residues have inhibitor effects. Therefore, a more detailed understanding of the diversity of HAO active site residues in soil microorganisms is important for the development of novel nitrification inhibitors using structure-guided drug design. However, this has not yet been examined. In the present study, we investigated hao gene diversity in beta-proteobacterial ammonia-oxidizing bacteria (β-AOB) and complete ammonia-oxidizing (comammox; Nitrospira spp.) bacteria in agricultural fields using a clone library ana-lysis. A total of 1,949 hao gene sequences revealed that hao gene diversity in β-AOB and comammox bacteria was affected by the fertilizer treatment and field type, respectively. Moreover, hao sequences showed the almost complete conservation of the six HAO active site residues in both β-AOB and comammox bacteria. The diversity of nitrifying bacteria showed similarity between hao and amoA genes. The nxrB amplicon sequence revealed the dominance of Nitrospira cluster II in tea field soils. The present study is the first to reveal hao gene diversity in agricultural soils, which will accelerate the efficient screening of HAO inhibitors and evaluations of their suppressive effects on nitrification in agricultural soils.

Characterization of a nitrite-reducing octaheme hydroxylamine oxidoreductase that lacks the tyrosine cross-link

The hydroxylamine oxidoreductase (HAO) family consists of octaheme proteins that harbor seven bis-His ligated electron-transferring hemes and one 5-coordinate catalytic heme with His axial ligation. Oxidative HAOs have a homotrimeric configuration with the monomers covalently attached to each other via a unique double cross-link between a Tyr residue and the catalytic heme moiety of an adjacent subunit. This cross-linked active site heme, termed the P460 cofactor, has been hypothesized to modulate enzyme reactivity toward oxidative catalysis. Conversely, the absence of this cross-link is predicted to favor reductive catalysis. However, this prediction has not been directly tested. In this study, an HAO homolog that lacks the heme-Tyr cross-link (HAOr) was purified to homogeneity from the nitrite-dependent anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis, and its catalytic and spectroscopic properties were assessed. We show that HAOr reduced nitrite to nitric oxide and also reduced nitric oxide and hydroxylamine as nonphysiological substrates. In contrast, HAOr was not able to oxidize hydroxylamine or hydrazine supporting the notion that cross-link-deficient HAO enzymes are reductases. Compared with oxidative HAOs, we found that HAOr harbors an active site heme with a higher (at least 80 mV) midpoint potential and a much lower degree of porphyrin ruffling. Based on the physiology of anammox bacteria and our results, we propose that HAOr reduces nitrite to nitric oxide in vivo, providing anammox bacteria with NO, which they use to activate ammonium in the absence of oxygen.

Do recovery outcome measures improve clinical practice? A linguistic analysis of the impact of the Hope, Agency and Opportunity measure in community mental health teams

AIMS

Recovery approaches are identified as the overarching framework for improving mental health services for people with severe and enduring conditions. These approaches prioritise living well with long-term conditions, as evidenced by personal recovery outcomes. There is little research demonstrating how to support busy mental health teams, work in this way. This study assessed the impact of introducing a brief measure of recovery, the Hope, Agency and Opportunity (HAO), on the attitudes and behaviours of staff working in community mental health teams, to test whether routine use of such measures facilitates recovery-based practice.

METHODS

Linguistic analysis assumes that language is indicative of wider attitudes and behaviours. Anonymised clinical notes recorded by community mental health team clinicians were analysed for recovery and non-recovery language, over 30 months. This covered periods before, during and after the introduction of the recovery measure. We used a single-case design (N = 1 community mental health team) and hypothesised that clinicians would use recovery-focused language more frequently, and non-recovery-focused language less frequently, following the introduction of the measure, and that these changes would be maintained at 18-month follow-up.

RESULTS

Visual inspection of the data indicated that recovery-focused language increased following the introduction of the HAO, though this was not maintained at follow-up. This pattern was not supported by statistical analyses. No clear pattern of change was found for non-recovery-focused language.

CONCLUSIONS

The introduction of a brief measure of recovery may have influenced staff attitudes and behaviours temporarily. Any longer term impact is likely to depend on ongoing commitment to the use of the measure, without which staff language, attitudes and behaviours return to previous levels.

A paradigm shift towards low-nitrifying production systems: the role of biological nitrification inhibition (BNI)

BACKGROUND

Agriculture is the single largest geo-engineering initiative that humans have initiated on planet Earth, largely through the introduction of unprecedented amounts of reactive nitrogen (N) into ecosystems. A major portion of this reactive N applied as fertilizer leaks into the environment in massive amounts, with cascading negative effects on ecosystem health and function. Natural ecosystems utilize many of the multiple pathways in the N cycle to regulate N flow. In contrast, the massive amounts of N currently applied to agricultural systems cycle primarily through the nitrification pathway, a single inefficient route that channels much of this reactive N into the environment. This is largely due to the rapid nitrifying soil environment of present-day agricultural systems.

SCOPE

In this Viewpoint paper, the importance of regulating nitrification as a strategy to minimize N leakage and to improve N-use efficiency (NUE) in agricultural systems is highlighted. The ability to suppress soil nitrification by the release of nitrification inhibitors from plant roots is termed 'biological nitrification inhibition' (BNI), an active plant-mediated natural function that can limit the amount of N cycling via the nitrification pathway. The development of a bioassay using luminescent Nitrosomonas to quantify nitrification inhibitory activity from roots has facilitated the characterization of BNI function. Release of BNIs from roots is a tightly regulated physiological process, with extensive genetic variability found in selected crops and pasture grasses. Here, the current status of understanding of the BNI function is reviewed using Brachiaria forage grasses, wheat and sorghum to illustrate how BNI function can be utilized for achieving low-nitrifying agricultural systems. A fundamental shift towards ammonium (NH4(+))-dominated agricultural systems could be achieved by using crops and pastures with high BNI capacities. When viewed from an agricultural and environmental perspective, the BNI function in plants could potentially have a large influence on biogeochemical cycling and closure of the N loop in crop-livestock systems.

An opiine Braconidae (Hymenoptera) reared from Richardiidae (Diptera) and recognition of a new species group of Opius s. l

A new species of opiine Braconidae, Opius rojam Daniels & Wharton, is described from Trinidad. The description is based in part on two individuals reared from Sepsisoma erythrocephalum infesting shoots of the grass Paspalum fasciculatum. This is the first record of members of the Opiinae attacking species in the dipteran family Richardiidae. The Opius ingenticornis species group is proposed and delineated to accommodate this and several putatively related species formerly included in Opius (Merotrachys), Opius (Pendopius), and Opius (Ilicopius). A key to the species of this group is provided. Descriptions and diagnoses are referenced to the Hymenoptera Anatomy Ontology.

New neotropical species of Opiinae (Hymenoptera, Braconidae) reared from fruit-infesting and leaf-mining Tephritidae (Diptera) with comments on the Diachasmimorpha mexicana species group and the genera Lorenzopius and Tubiformopius

Four new species of opiine Braconidae are described from Mexico. These are Diachasmimorpha martinalujai Wharton reared from Rhagoletis infesting fruits of Crataegus spp., Diachasmimorpha norrbomi Wharton reared from Euphranta mexicana infesting fruits of Ribes pringlei, Eurytenes (Stigmatopoea) norrbomi Wharton reared from Trypeta concolor mining leaves of Barkleyanthus salicifolia and Eurytenes (Stigmatopoea) maya Wharton reared from Rhagoletis pomonella infesting apples and fruits of Crataegus spp. Morphological features of the first metasomal segment and occipital carina, useful for placement of these species, are discussed relative to the genera Diachasmimorpha, Eurytenes, Lorenzopius, Tubiformopius, and Opius s.l. Descriptions and diagnoses are referenced to the Hymenoptera Anatomy Ontology. The following represent new combinations: Diachasmimorpha hildagensis, Lorenzopius euryteniformis, and Tubiformopius tubibasis. Revised diagnoses are provided for Diachasmimorpha hildagensis, Diachasmimorpha mexicana, Diachasmimorpha sanguinea, Eurytenes (Stigmatopoea), Lorenzopius, Lorenzopius euryteniformis, Tubiformopius, Tubiformopius tubigaster, Tubiformopius tubibasis, Opius incoligma, and Opius rugicoxis. Two species groups are delineated within Lorenzopius and a key to species of Diachasmimorpha occurring in the New World is provided.