Controlling the Superconductivity of Nb2PdxS5 via Reversible Li Intercalation.

The Nb2PdxS5 (x ≈ 0.74) superconductor with a Tc of 6.5 K is reduced by the intercalation of lithium in ammonia solution or electrochemically to produce an intercalated phase with expanded lattice parameters. The structure expands by 2% in volume and maintains the C2/m symmetry and rigidity due to the PdS4 units linking the layers. Experimental and computational analysis of the chemically synthesized bulk sample shows that Li occupies triangular prismatic sites between the layers with an occupancy of 0.33(4). This level of intercalation suppresses the superconductivity, with the injection of electrons into the metallic system observed to also reduce the Pauli paramagnetism by ∼40% as the bands are filled to a Fermi level with a lower density of states than in the host material. Deintercalation using iodine partially restores the superconductivity, albeit at a lower Tc of ∼5.5 K and with a smaller volume fraction than in fresh Nb2PdxS5. Electrochemical intercalation reproduces the chemical intercalation product at low Li content (<0.4) and also enables greater reduction, but at higher Li contents (≥0.4) accessed by this route, phase separation occurs with the indication that Li occupies another site.

Staphylococcus aureus FadB is a dehydrogenase that mediates cholate resistance and survival under human colonic conditions.

Staphylococcus aureus is a common colonizer of the human gut and in doing so it must be able to resist the actions of the host's innate defences. Bile salts are a class of molecules that possess potent antibacterial activity that control growth. Bacteria that colonize and survive in that niche must be able to resist the action of bile salts, but the mechanisms by which S. aureus does so are poorly understood. Here we show that FadB is a bile-induced oxidoreductase which mediates bile salt resistance and when heterologously expressed in Escherichia coli renders them resistant. Deletion of fadB attenuated survival of S. aureus in a model of the human distal colon.

Bacterial peritonitis in paediatric appendicitis; microbial epidemiology and antimicrobial management.

BACKGROUND: Appendicitis remains a common surgical emergency in children. Empirical antibacterial treatment is indicated to reduce infective complications. We investigate the bacterial pathogens identified intra-operatively during appendectomies in children to guide empirical surgical antimicrobial prophylaxis options. METHODS: A retrospective analysis of patients (< 18 years old) undergoing an appendectomy across a multisite London hospital (Nov 2019-March 2022) was undertaken. Patient-related outcomes including length of hospital stay (LOS), days of antibacterial therapy (DOT), intra-operative microbiology and post-operative radiology reports were interrogated. RESULTS: 304 patients underwent an appendectomy during this period; 39.1% of patients had intraoperative samples cultured. Bacterial pathogens were found in 73/119 (61.3%) cases; the most common isolates being Escherichia coli (42.0%), Pseudomonas aeruginosa (21.0%), milleri Streptococcus spp. (14.3%) and Bacteroides fragilis (5.9%). Polymicrobial infection was common (32/73). Isolation of Pseudomonas spp. from intra-operative sampling was associated with a greater LOS (7.0 vs. 5.0 days; p = 0.011) but nil effect on the incidence of postoperative collections. Presence of milleri Streptococcus spp. was associated with longer LOS (7.0 vs. 5.0 day; p = 0.007), DOT (12.0 vs. 8.5 day; p = 0.007) but had no observed outcome on postoperative collections (29.4% vs. 18.6%; p = 0.330). 48% of E. coli positive cultures were co-amoxiclav resistant and prolonged LOS compared to the non-resistant group (7.0 vs. 5.0 days; p = 0.040) but had no difference in post-operative collections (29.2% vs. 17.9%; p = 0.260). CONCLUSION: A high proportion of children with appendicitis have Pseudomonas spp. isolated, leading to a prolonged LOS. Evolving Enterobacterales resistance and the presence of Pseudomonas spp. necessitate extended antibacterial coverage for paediatric appendectomies with evidence of peritonitis.

Structures and Magnetic Ordering in Layered Cr Oxide Arsenides Sr2CrO2Cr2OAs2 and Sr2CrO3CrAs.

Two novel chromium oxide arsenide materials have been synthesized, Sr2CrO2Cr2OAs2 (i.e., Sr2Cr3As2O3) and Sr2CrO3CrAs (i.e., Sr2Cr2AsO3), both of which contain chromium ions in two distinct layers. Sr2CrO2Cr2OAs2 was targeted following electron microscopy measurements on a related phase. It crystallizes in the space group P4/mmm and accommodates distorted CrO4As2 octahedra containing Cr2+ and distorted CrO2As4 octahedra containing Cr3+. In contrast, Sr2CrO3CrAs incorporates Cr3+ in CrO5 square-pyramidal coordination in [Sr2CrO3]+ layers and Cr2+ ions in CrAs4 tetrahedra in [CrAs]- layers and crystallizes in the space group P4/nmm. Powder neutron diffraction data reveal antiferromagnetic ordering in both compounds. In Sr2CrO3CrAs the Cr2+ moments in the [CrAs]- layers exhibit long-range ordering, while the Cr3+ moments in the [Sr2CrO3]+ layers only exhibit short-range ordering. However, in Sr2CrO2Cr2OAs2, both the Cr2+ moments in the CrO4As2 environments and the Cr3+ moments in the CrO2As4 polyhedra are long-range-ordered below 530(10) K. Above this temperature, only the Cr3+ moments are ordered with a Néel temperature slightly in excess of 600 K. A subtle structural change is evident in Sr2CrO2Cr2OAs2 below the magnetic ordering transitions.

Learning how relationships work: a thematic analysis of young people and relationship professionals' perspectives on relationships and relationship education.

BACKGROUND: Relationships in various forms are an important source of meaning in people's lives that can benefit their health, wellbeing and happiness. Relationship distress is associated with public health problems such as alcohol misuse, obesity, poor mental health, and child poverty, whilst safe, stable, and nurturing relationships are potential protective factors. Despite increased emphasis on Relationship Education in schools, little is known about the views of relationship professionals on relationship education specifically, and how this contrasts with the views of young people (YP). This Wellcome Centre for the Cultures and Environments of Health funded Beacon project seeks to fill this gap by exploring their perspectives and inform the future development of relationship education. METHODS: We conducted focus groups with YP (n = 4) and interviews with relationship professionals (n = 10). The data was then thematically analysed. RESULTS: Themes from YP focus groups included: 'Good and bad relationships'; 'Learning about relationships'; 'the role of schools' and 'Beyond Relationship Education'. Themes from interviews with relationship professionals included: 'essential qualities of healthy relationships'; 'how YP learn to relate' and 'the role of Relationship Education in schools'. CONCLUSIONS: YP and relationship professionals recognised the importance of building YP's relational capability in schools with a healthy relationship with oneself at its foundation. Relationship professionals emphasised the need for a developmental approach, stressing the need for flexibility, adaptability, commitment and resilience to maintain relationships over the life course. YP often presented dichotomous views, such as relationships being either good or bad relationships, and perceived a link between relationships and mental health. Although not the focus of current curriculum guidance, managing relationship breakdowns and relationship transitions through the life course were viewed as important with an emphasis on building relational skills. This research suggests that schools need improved Relationship Education support, including specialist expertise and resources, and guidance on signposting YP to external sources of help. There is also potential for positive relationship behaviours being modelled and integrated throughout curriculums and reflected in a school's ethos. Future research should explore co-development, evaluation and implementation of Relationship Education programmes with a range of stakeholders.

Development and validation of a novel 3D-printed simulation model for open oesophageal atresia and tracheo-oesophageal fistula repair.

BACKGROUND: The role of simulation training in paediatric surgery is expanding as more simulation devices are designed and validated. We aimed to conduct a training needs assessment of UK paediatric surgical trainees to prioritise procedures for simulation, and to validate a novel 3D-printed simulation model for oesophageal atresia and tracheo-oesophageal fistula (OA-TOF) repair. METHODS: A questionnaire was sent to UK trainee paediatric surgeons surveying the availability and utility of simulation. The operation ranked as most useful to simulate was OA-TOF repair. 3D-printing techniques were used to build an OA-TOF model. Content, face and construct validity was assessed by 40 paediatric surgeons of varying experience. RESULTS: Thirty-four paediatric surgeons completed the survey; 79% had access to surgical simulation at least monthly, and 47% had access to paediatric-specific resources. Perceived utility of simulation was 4.1/5. Validation of open OA-TOF repair was conducted by 40 surgeons. Participants rated the model as useful 4.9/5. Anatomical realism was scored 4.2/5 and surgical realism 3.9/5. The model was able to discriminate between experienced and inexperienced surgeons. CONCLUSION: UK paediatric surgeons voted OA-TOF repair as the most useful procedure to simulate. In response we have developed and validated an affordable 3D-printed simulation model for open OA-TOF repair.

Compulsory Vaccination and Nozickian Rights.

This article examines compulsory vaccination from the perspective of Nozick's theory of rights. It argues that the unvaccinated are a threat, even if unintended, to the rights of others. The reasons Nozick provides for when such threats may be forcibly prevented, such as the identifiability of the rights violator, general fear of the risky activity, probability of harm, and the general benefits of the activity, are examined, and it is argued that those reasons weigh in favour of prohibition of the threat and hence in favour of compulsory vaccination. It is also argued that anyone opposed to compulsory vaccination on Nozickian grounds faces a dilemma: if they reject compulsory vaccination, they also risk rejecting the very foundations of the legitimacy of the state.

White matter microstructural differences in underweight adolescents with anorexia nervosa and a preliminary longitudinal investigation of change following short-term weight restoration.

PURPOSE: Anorexia nervosa (AN) affects approximately 2.9% of females and has the highest mortality rate among all psychiatric disorders. Despite several advances, the neurobiology of this disorder is still not well understood. Several studies have reported abnormalities in the white matter, but it is not know if these are disease-related or secondary to undernutrition. This study aimed to further our understanding of white matter pathology using diffusion-weighted imaging in underweight adolescents with AN, and to examine changes occurring after short-term weight restoration. METHODS: Analyses were conducted on diffusion-weighted imaging from 24 female adolescents with AN and 17 age- and gender-matched healthy controls (HC), aged 14-19 years. Groups were compared on fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) using tract-based spatial statistics analysis and DTI measures were correlated with eating disorder examination questionnaire (EDE-Q) subscales and body mass index (BMI). Preliminary repeated-measure analyses were also conducted on eight participants after short-term weight restoration (median 41 days). RESULTS: Widespread increases in MD of up to 9% were found in underweight AN relative to HC, particularly in the corpus callosum. This was associated with both increased AD and RD, suggestive of dys- or de-myelination. There were no significant group differences in FA, and no significant correlations between DTI measures, BMI or EDE-Q subscale score. Weight restoration therapy significantly reduced MD, to levels significantly lower than HC, but did not consistently alter FA across individuals. CONCLUSIONS: White matter microstructure is significantly altered in female adolescents with AN, with preliminary longitudinal data suggesting that it may be reversible with short-term weight restoration. LEVEL OF EVIDENCE: Level III: evidence obtained from well-designed cohort or case-control analytic studies.

Using smart-messaging to enhance mindfulness-based cognitive therapy for cancer patients: A mixed methods proof of concept evaluation.

OBJECTIVE: Depression and anxiety lead to reduced treatment adherence, poorer quality of life, and increased care costs amongst cancer patients. Mindfulness-based cognitive therapy (MBCT) is an effective treatment, but dropout reduces potential benefits. Smart-message reminders can prevent dropout and improve effectiveness. However, smart-messaging is untested for MBCT in cancer. This study evaluates smart-messaging to reduce dropout and improve effectiveness in MBCT for cancer patients with depression or anxiety. METHODS: Fifty-one cancer patients attending MBCT in a psycho-oncology service were offered a smart-messaging intervention, which reminded them of prescribed between-session activities. Thirty patients accepted smart-messaging and 21 did not. Assessments of depression and anxiety were taken at baseline, session-by-session, and one-month follow-up. Logistic regression and multilevel modelling compared the groups on treatment completion and clinical effectiveness. Fifteen post-treatment patient interviews explored smart-messaging use. RESULTS: The odds of programme completion were eight times greater for patients using smart-messaging compared with non-users, controlling for age, gender, baseline depression, and baseline anxiety (OR = 7.79, 95% CI 1.75 to 34.58, p = .007). Smart-messaging users also reported greater improvement in depression over the programme (B = -2.33, SEB = .78, p = .004) when controlling for baseline severity, change over time, age, and number of sessions attended. There was no difference between groups in anxiety improvement (B = -1.46, SEB = .86, p = .097). In interviews, smart-messaging was described as a motivating reminder and source of personal connection. CONCLUSIONS: Smart-messaging may be an easily integrated telehealth intervention to improve MBCT for cancer patients.

Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2.

Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1_Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1_Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) µB (for Sr2CrO2Cr2As2) and 3.30(1) µB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) µB for Sr2CrO2Cr2As2 and 2.298(8) µB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers.

Do emotional responses to food images differ within different types of eating disorders?

OBJECTIVES: To investigate emotional responses to food images in women with eating disorders (EDs) and healthy controls (HCs); and in underweight individuals post weight-restoration. METHODS: Women (>14 years) with (n = 139) and without (n = 41) an ED rated food images evoking fear, disgust and happiness on a three-visual-analogue scale. Underweight participants viewed the images at two time-points; pre- and post-weight-restoration. RESULTS: HCs were significantly happier, less fearful/anxious prior to viewing the images compared with EDs. Negative emotional responses when viewing images were significantly greater (p < .001) in EDs compared with HCs; however, groups did not differ in happiness. Emotional responses were not significantly different within the ED groups. At post weight-restoration, individuals were significantly less anxious/disgusted when viewing the images. CONCLUSIONS: The importance of considering emotional responses when discussing food consumption in EDs trans-diagnostically is highlighted. Weight recovery reduces negative food responses, although responses remained high in comparison to HCs.

Expression Patterns of Genes Encoding Sugar and Potassium Transport Proteins Are Simultaneously Upregulated or Downregulated When Carbon and Potassium Availability Is Modified in Shiraz (Vitis vinifera L.) Berries.

A link between the accumulation of sugar and potassium has previously been described for ripening grape berries. The functional basis of this link has, as of yet, not been elucidated but could potentially be associated with the integral role that potassium has in phloem transport. An experiment was conducted on Shiraz grapevines in a controlled environment. The accumulation of berry sugar was curtailed by reducing the leaf photoassimilation rate, and the availability of potassium was increased through soil fertilization. The study characterizes the relationship between the accumulation of sugar and potassium into the grape berry and describes how their accumulation patterns are related to the expression patterns of their transporter proteins. A strong connection was observed between the accumulation of sugar and potassium in the grape berry pericarp, irrespective of the treatment. The relative expression of proteins associated with sugar and potassium transport across the tonoplast and plasma membrane was closely correlated, suggesting transcriptional coregulation leading to the simultaneous translocation and storage of potassium and sugar in the grape berry cell.

Synthesis, Structure, and Compositional Tuning of the Layered Oxide Tellurides Sr2MnO2Cu2- xTe2 and Sr2CoO2Cu2Te2.

The synthesis and structure of two new transition metal oxide tellurides, Sr2MnO2Cu1.82(2)Te2 and Sr2CoO2Cu2Te2, are reported. Sr2CoO2Cu2Te2 with the purely divalent Co2+ ion in the oxide layers has magnetic ordering based on antiferromagnetic interactions between nearest neighbors and appears to be inert to attempted topotactic oxidation by partial removal of the Cu ions. In contrast, the Mn analogue with the more oxidizable transition metal ion has a 9(1)% Cu deficiency in the telluride layer when synthesized at high temperatures, corresponding to a Mn oxidation state of +2.18(2), and neutron powder diffraction revealed the presence of a sole highly asymmetric Warren-type magnetic peak, characteristic of magnetic ordering that is highly two-dimensional and not fully developed over a long range. Topotactic oxidation by the chemical deintercalation of further copper using a solution of I2 in acetonitrile offers control over the Mn oxidation state and, hence, the magnetic ordering: oxidation yielded Sr2MnO2Cu1.58(2)Te2 (Mn oxidation state of +2.42(2)) in which ferromagnetic interactions between Mn ions result from Mn2+/3+ mixed valence, resulting in a long-range-ordered A-type antiferromagnet with ferromagnetic MnO2 layers coupled antiferromagnetically.

Layered CeSO and LiCeSO Oxide Chalcogenides Obtained via Topotactic Oxidative and Reductive Transformations.

The chemical accessibility of the CeIV oxidation state enables redox chemistry to be performed on the naturally coinage-metal-deficient phases CeM1- xSO (M = Cu, Ag). A metastable black compound with the PbFCl structure type (space group P4/ nmm: a = 3.8396(1) Å, c = 6.607(4) Å, V = 97.40(6) Å3) and a composition approaching CeSO is obtained by deintercalation of Ag from CeAg0.8SO. High-resolution transmission electron microscopy reveals the presence of large defect-free regions in CeSO, but stacking faults are also evident which can be incorporated into a quantitative model to account for the severe peak anisotropy evident in all the high-resolution X-ray and neutron diffractograms of bulk CeSO samples; these suggest that a few percent of residual Ag remains. A straw-colored compound with the filled PbFCl (i.e., ZrSiCuAs- or HfCuSi2-type) structure (space group P4/ nmm: a = 3.98171(1) Å, c = 8.70913(5) Å, V = 138.075(1) Å3) and a composition close to LiCeSO, but with small amounts of residual Ag, is obtained by direct reductive lithiation of CeAg0.8SO or by insertion of Li into CeSO using chemical or electrochemical means. Computation of the band structure of pure, stoichiometric CeSO predicts it to be a Ce4+ compound with the 4f-states lying approximately 1 eV above the sulfide-dominated valence band maximum. Accordingly, the effective magnetic moment per Ce ion measured in the CeSO samples is much reduced from the value found for the Ce3+-containing LiCeSO, and the residual paramagnetism corresponds to the Ce3+ ions remaining due to the presence of residual Ag, which presumably reflects the difficulty of stabilizing Ce4+ in the presence of sulfide (S2-). Comparison of the behavior of CeCu0.8SO with that of CeAg0.8SO reveals much slower reaction kinetics associated with the Cu1- xS layers, and this enables intermediate CeCu1- xLi xSO phases to be isolated.

ELDOR-detected NMR beyond hyperfine couplings: a case study with Cu(ii)-porphyrin dimers.

The pulse EPR method ELDOR-detected NMR (EDNMR) is applied to two Cu(ii)-porphyrin dimers that are suitable building blocks for molecular wires. One of the dimers is meso-meso singly linked, the other one is ß, meso, ß-fused. We show experimentally and theoretically that EDNMR spectra contain information about the electron-electron couplings. The spectra of the singly linked dimer are consistent with a perpendicular arrangement of the porphyrin planes and negligible exchange coupling. In addition, the resolution is good enough to distinguish 63Cu and 65Cu in frozen glassy solution and to resolve a metal-ion nuclear quadrupole coupling of 32 MHz. In the case of the fused dimer, we observe so far unreported signal enhancements, or anti-holes, in the EDNMR spectra. These are readily explained in a generalized framework based on [Cox et al., J. Magn. Reson., 2017, 280, 63-78], if an effective spin of S = 1 is assumed, in accordance with SQUID measurements. The positions of the anti-holes encode a zero-field splitting with |D| = 240 MHz, which is about twice as large as expected from the point-dipole approximation. These findings demonstrate the previously unrecognized applicability and versatility of the EDNMR technique in the quantitative study of complex paramagnetic compounds.

In-situ Electrochemical X-ray Diffraction: A Rigorous Method to Navigate within Phase Diagrams Reveals ß-Fe1+x Se as Superconductor for All x.

We report the precise postsynthetic control of the composition of ß-Fe1+x Se by electrochemistry with simultaneous tracking of the associated structural changes via in situ synchrotron X-ray diffraction. We access the full phase width of 0.01

Effects of starvation and short-term refeeding on gastric emptying and postprandial blood glucose regulation in adolescent girls with anorexia nervosa.

Postprandial glucose is reduced in malnourished patients with anorexia nervosa (AN), but the mechanisms and duration for this remain unclear. We examined blood glucose, gastric emptying, and glucoregulatory hormone changes in malnourished patients with AN and during 2 wk of acute refeeding compared with healthy controls (HCs). Twenty-two female adolescents with AN and 17 age-matched female HCs were assessed after a 4-h fast. Patients were commenced on a refeeding protocol of 2,400 kcal/day. Gastric emptying (13C-octanoate breath test), glucose absorption (3-O-methylglucose), blood glucose, plasma glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), insulin, C-peptide, and glucagon responses to a mixed-nutrient test meal were measured on admission and 1 and 2 wk after refeeding. HCs were assessed once. On admission, patients had slower gastric emptying, lower postprandial glucose and insulin, and higher glucagon and GLP-1 than HCs ( P < 0.05). In patients with AN, the rise in glucose (0-30 min) correlated with gastric emptying ( P < 0.05). With refeeding, postprandial glucose and 3-O-methylglucose were higher, gastric emptying faster, and baseline insulin and C-peptide less ( P < 0.05), compared with admission. After 2 wk of refeeding, postprandial glucose remained lower, and glucagon and GLP-1 higher, in patients with AN than HCs ( P < 0.05) without differences in gastric emptying, baseline glucagon, or postprandial insulin. Delayed gastric emptying may underlie reduced postprandial glucose in starved patients with AN; however, postprandial glucose and glucoregulatory hormone changes persist after 2 wk of refeeding despite improved gastric emptying. Future research should explore whether reduced postprandial glucose in AN is related to medical risk by examining associated symptoms alongside continuous glucose monitoring during refeeding.

Synthesis, Structure, and Properties of the Layered Oxide Chalcogenides Sr2CuO2Cu2S2 and Sr2CuO2Cu2Se2.

The structures of two new oxide chalcogenide phases, Sr2CuO2Cu2S2 and Sr2CuO2Cu2Se2, are reported, both of which contain infinite CuO2 planes containing Cu2+ and which have Cu+ ions in the sulfide or selenide layers. Powder neutron diffraction measurements show that Sr2CuO2Cu2Se2 exhibits long-range magnetic ordering with a magnetic structure based on antiferromagnetic interactions between nearest-neighbor Cu2+ ions, leading to a √2 a × âˆš2 a × 2 c expansion of the nuclear cell. The ordered moment of 0.39(6) µB on the Cu2+ ions at 1.7 K is consistent with the value predicted by density functional theory calculations. The compounds are structurally related to the cuprate superconductors and may also be considered as analogues of the parent phases of this class of superconductor such as Sr2CuO2Cl2 or La2CuO4. In the present case, however, the top of the chalcogenide-based valence band is very close to the vacant Cu2+ 3d states of the conduction band, leading to relatively high measured conductivity.

Complex Magnetic Ordering in the Oxide Selenide Sr2Fe3Se2O3.

Sr2Fe3Se2O3 is a localized-moment iron oxide selenide in which two unusual coordinations for Fe2+ ions form two sublattices in a 2:1 ratio. In the paramagnetic region at room temperature, the compound adopts the crystal structure first reported for Sr2Co3S2O3, crystallizing in space group Pbam with a = 7.8121 Å, b = 10.2375 Å, c = 3.9939 Å, and Z = 2. The sublattice occupied by two-thirds of the iron ions (Fe2 site) is formed by a network of distorted mer-[FeSe3O3] octahedra linked via shared Se2 edges and O vertices forming layers, which connect to other layers by shared Se vertices. As shown by magnetometry, neutron powder diffraction, and Mössbauer spectroscopy measurements, these moments undergo long-range magnetic ordering below TN1 = 118 K, initially adopting a magnetic structure with a propagation vector (1/2 - δ, 0, 1/2) (0 ≤ δ ≤ 0.1) which is incommensurate with the nuclear structure and described in the Pbam1 '( a01/2)000 s magnetic superspace group, until at 92 K ( TINC) there is a first order lock-in transition to a structure in which these Fe2 moments form a magnetic structure with a propagation vector (1/2, 0, 1/2) which may be modeled using a 2 a × b × 2 c expansion of the nuclear cell in space group 36.178 B a b21 m (BNS notation). Below TN2 = 52 K the remaining third of the Fe2+ moments (Fe1 site) which are in a compressed trans-[FeSe4O2] octahedral environment undergo long-range ordering, as is evident from the magnetometry, the Mössbauer spectra, and the appearance of new magnetic Bragg peaks in the neutron diffractograms. The ordering of the second set of moments on the Fe1 sites results in a slight reorientation of the majority moments on the Fe2 sites. The magnetic structure at 1.5 K is described by a 2 a × 2 b × 2 c expansion of the nuclear cell in space group 9.40 I a b (BNS notation).