Orbital Dimer Model for Spin-Glass State in Y2_2Mo2_2O7_7

The formation of a spin glass usually requires both structural disorder and frustrated magnetic interactions. Consequently, the origin of spin-glass behaviour in Y$_2$Mo$_2$O$_7$ $-$ in which magnetic Mo$^{4+}$ ions occupy a frustrated pyrochlore lattice with minimal compositional disorder $-$ has been a longstanding question. Here, we use neutron and X-ray pair-distribution function (PDF) analysis to develop a disorder model that resolves apparent incompatibilities between previously-reported PDF, EXAFS and NMR studies and provides a new and physical mechanism for spin-glass formation. We show that Mo$^{4+}$ ions displace according to a local "2-in/2-out" rule on each Mo$_4$ tetrahedron, driven by orbital dimerisation of Jahn-Teller active Mo$^{4+}$ ions. Long-range orbital order is prevented by the macroscopic degeneracy of dimer coverings permitted by the pyrochlore lattice. Cooperative O$^{2-}$ displacements yield a distribution of Mo$-$O$-$Mo angles, which in turn introduces disorder into magnetic interactions. Our study demonstrates experimentally how frustration of atomic displacements can assume the role of compositional disorder in driving a spin-glass transition.Comment: 6 pages, 3 figure

Characteristics and candidate genes associated with excellent stalk strength in maize (Zea mays L.)

Lodging is a major problem in maize production, which seriously affects yield and hinders mechanized harvesting. Improving stalk strength is an effective way to improve lodging. The maize inbred line Jing2416 (J2416) was an elite germplasm in maize breeding which had strong stalk mechanical strength. To explore the characteristics its stalk strength, we conducted physiological, metabolic and transcriptomic analyses of J2416 and its parents Jing24 (J24) and 5237. At the kernel dent stage, the stalk rind penetrometer strength of J2416 was significantly higher than those of its two parents in multiple environments. The rind thickness, sclerenchyma tissue thickness, and cellulose, hemicellulose, and lignin contents of J2416 were significantly higher than those of its parents. Based on the significant differences between J2416 and 5237, we detected metabolites and gene transcripts showing differences in abundance between these two materials. A total of 212 (68.60%) metabolites and 2287 (43.34%) genes were up-regulated in J2416 compared with 5237. The phenylpropanoid and glycan synthesis/metabolism pathways were enriched in metabolites and genes that were up-regulated in J2416. Twenty-eight of the up-regulated genes in J2416 were involved in lignin, cellulose, and hemicellulose synthesis pathways. These analyses have revealed important physiological characteristics and candidate genes that will be useful for research and breeding of inbred lines with excellent stalk strength

Metabolic risk factors of cognitive impairment in young women with major psychiatric disorder

BackgroundCognitive performance improves clinical outcomes of patients with major psychiatric disorder (MPD), but is impaired by hyperglycemia. Psychotropic agents often induce metabolism syndrome (MetS). The identification of modifiable metabolic risk factors of cognitive impairment may enable targeted improvements of patient care.ObjectiveTo investigate the relationship between MetS and cognitive impairment in young women with MPD, and to explore risk factors.MethodsWe retrospectively studied women of 18–34 years of age receiving psychotropic medications for first-onset schizophrenia (SCH), bipolar disorder (BP), or major depressive disorder (MDD). Data were obtained at four time points: presentation but before psychotropic medication; 4–8 and 8–12 weeks of psychotropic therapy; and enrollment. MATRICS Consensus Cognitive Battery, (MCCB)—based Global Deficit Scores were used to assess cognitive impairment. Multiple logistic analysis was used to calculate risk factors. Multivariate models were used to investigate factors associated with cognitive impairment.ResultsWe evaluated 2,864 participants. Cognitive impairment was observed in 61.94% of study participants, and was most prevalent among patients with BP (69.38%). HbA1c within the 8–12 week-treatment interval was the most significant risk factor and highest in BP. Factors in SCH included pre-treatment waist circumference and elevated triglycerides during the 8–12 weeks treatment interval. Cumulative dosages of antipsychotics, antidepressants, and valproate were associated with cognitive impairment in all MPD subgroups, although lithium demonstrated a protect effect (all P < 0.001).ConclusionsCognitive impairment was associated with elevated HbA1c and cumulative medication dosages. Pre-treatment waist circumference and triglyceride level at 8–12 weeks were risk factors in SCH. Monitoring these indices may inform treatment revisions to improve clinical outcomes

Topochemical fluorination of some Ruddlesden-Popper phases

This thesis describes the synthesis and the characterization of some n = 2 Ruddlesden-Popper oxide phases (A3B2O7; A = La, Y, Sr or Ca; B = Cr, Ni or Mn) and their topochemically fluorinated phases. La2SrCr2O7 adopts an A2/a (a-a-c-/a-a-c-) distorted structure with antiferromagnetic order below TN ~ 260 K. DFT calculations performed on La2SrCr2O7 suggest that this highly distorted A2/a (a-a-c-/a-a-c-) structure is stabilized by energy gains from the charge equalization and the improvement of chromium bonding environments associated with the unusual Sr/La distribution exhibited by this phase (the 12-coordinate A-sites are occupied by 82(2)% La3+ and 18(2)% Sr2+). Topochemical fluorination of La2SrCr2O7 (Cr3+) yields La2SrCr2O7F2 (Cr4+) adopting the A2/a (a-a-c-/a-a-c-) distortion with antiferromagnetic order below TN ~ 140 K. The fluorination leads a great compression of the perovskite layer within the Ruddlesden-Popper structure, enhancing the (a-a-c-/a-a-c-) distortion. As a result La2SrCr2O7F2 lies further from the crossover for insulating to metallic behaviour than many other Cr4+ oxide phases. The A-site doping in La2SrCr2O7 for the preparation of La2-xSr1+xCr2O7 (x = 0.2, 0.3) and La2Sr0.5Ca0.5Cr2O7 leads to no obvious change in structural framework and the antiferromagnetic behaviour. La2-xSr1+xCr2O7F2 (x = 0.2, 0.3) behaves similarly to La2SrCr2O7F2. Topochemical fluorination of La3Ni2O7 yields La3Ni2O5.5F3.5 with no obvious magnetic order. The fluorination leads to an enhancement of the structural distortion exhibited by the oxide starting material, driving a change from an Amam, a-a-c0/a-a-c0 lattice distortion to a Pnam a-a-c+/a-a-(c+) lattice distortion in the fluorinated phase. The introduction of a cooperative octahedral tilt around the crystallographic z-axis leads to a local breaking of the inversion symmetry of the host lattice on fluorination, although the global inversion symmetry of the lattice is retained due to an alternation in the z-tilt direction in adjacent perovskite sheets. The substitution of Sr2+ with Ca2+ cations in YSr2Mn2O7 led to an increasing distortion of the metal-oxide framework, resulting in the formation of an orthorhombic symmetry in space group Pnnm adopted by YSr0.5Ca1.5Mn2O7. This novel Pnnm (a-b-c0/b-a-c0, a ≠ b) distortion can be seen as an intermediate in structural change from P42/mnm (a-b0c0/b0a-c0) to Amam (a-a-c0/a-a-c0). The topochemical fluorination of YSr2Mn2O7 yields YSr2Mn2O5.5F3.5 with P42/mnm (a-b0c0/b0a-c0) distortion. The fluorination YSr2Mn2O7 does not lead to a structural change as observed in that of La3Ni2O7. This preference of retaining relatively high symmetry is driven by the A-cation ordering over the 9- and 12-coordinate A-sites in YSr2Mn2O5.5F3.5.</p

Taugt17b1 Overexpression in Trichoderma atroviride Enhances Its Ability to Colonize Roots and Induce Systemic Defense of Plants

Trichoderma atroviride, a soil fungus, has important applications in the biocontrol of plant diseases. Glycosyltransferases enhance the root colonization ability of Trichoderma spp. This study aimed to functionally characterize glycosyltransferase Taugt17b1 in T. atroviride. We investigated the effect of Taugt17b1 overexpression in T. atroviride H18-1-1 on its biocontrol properties, especially its ability to colonize roots. Our results demonstrated that the overexpression of the Taugt17b1 increases the T. atroviride colony growth rate, improves its root colonization ability, promotes the growth and activity of the defensive enzymatic system of plants, and prevents plant diseases. This study put forth a new role of T. atroviride glycosyltransferase and furthered the understanding of the mechanisms by which fungal biocontrol agents exert their effect

The Efficacy and Safety of Baduanjin in Patients with Coronary Heart Disease After Percutaneous Coronary Intervention：A protocol for systematic review and meta-analysis

Abstract: Objective: To evaluate the effects of Baduanjin on quality of life (QOL), psychological status and cardiac function of patients with coronary heart disease after percutaneous coronary intervention (PCI). Methods: PubMed, The Cochrance Library, Embase, Web of Science, China Biology Medicine disc, CNKI, VIP and Wanfang were searched by a computer for any randomized controlled trials of Baduanjin intervention in patients with coronary heart disease after PCI, including relevant conference articles and academic papers published in journals. The retrieval time was from the database creation time to September 7, 2020. After two evaluators independently screened the literature, extracted relevant data and evaluated the bias risk for the included studies, RevMan5.3 software was used for a data analysis. Results: A total of 9 articles and 846 patients were included. The meta-analysis showed that the Baduanjin group was superior to the conventional western medicine treatment group in Physical Functioning (PF) [MD=5.36, 95%(2.86, 7.86), P&lt;0.0001)], Role-Physical (RP) [MD=17.88, 95% (10.09 (25.67) , P&lt;0.00001)], Bodily Pain (BP)[MD=5.86, 95% (-4.65, 16.36) , P=0.27)], General Health (GH) [MD=12.78, 95% (9.57, 15.99) , P&lt;0.00001)], Vitality (VT) [MD=8.43, 95% (0.10, 16.77) , P=0.05)], Social Functioning (SF) [MD=8.11, 95% (-3.99, 20.22) , P=0.19)], Role-Emotional (RE) [MD=15.01, 95% (4.16, 25.85) , P=0.007)], Mental Health (MH) [MD=7.54, 95% (4.78, 10.30) , P&lt;0.00001)], anxiety[MD=-6.10, 95% (-7.24, -4.96) , P&lt;0.00001)], depression[MD=-6.25, 95% (-8.52, -3.97) , P&lt;0.00001)], Left ventricular ejection fraction (LVEF)[MD=3.90, 95% (1.58, 6.22) , P=0.001)], Blood pressure (BP) [MD=-11.37, 95% (-16.20, -6.54) , P&lt;0.00001)], Stroke volume (SV)[MD=7.25, 95% (4.68, 9.82) , P&lt;0.00001)], and the differences were statistically significant. Conclusion: Baduanjin can improve the cardiac function, regulate the psychological state and improve the QOL among patients with coronary heart disease after PCI

Directed Lifting of Inversion Symmetry in Ruddlesden–Popper Oxide–Fluorides: Toward Ferroelectric and Multiferroic Behavior

The cooperative tilting distortions of <i>n</i> = 2 Ruddlesden–Popper oxides can be utilized to break the inversion symmetry of the host lattice and induce ferroelectric behavior. Unfortunately the desired a^–a^–c⁺/a^–a^–c⁺ structural deformation is only stabilized in phases with extremely small structural tolerance factors, limiting the chemical scope of this symmetry breaking approach. Here we describe the influence of topochemical fluorination on the structural distortions of <i>n</i> = 2 Ruddlesden–Popper oxides and demonstrate that the conversion of La₃Ni₂O₇ to La₃Ni₂O_5.5F_3.5 breaks the inversion symmetry of the perovskite double layers which constitute the Ruddlesden–Popper framework, by driving a change from an a^–a^–c⁰/a^–a^–c⁰ distortion in the parent phase to an a^–a^–c⁺/a^–a^–-(c⁺) distortion in the oxide–fluoride. In this instance, the symmetry breaking distortions of adjacent acentric perovskite sheets are antialigned, and as a result the inversion symmetry of the host lattice is broken locally, but not globally, resulting in an antiferroelectric structure. The breaking of local inversion symmetry in layered perovskite phases, in the absence of second-order Jahn–Teller active “distortion centers”, is an important step toward the realization of ferroelectric and multiferroic behavior in phases of this structure type

CONSTANS-LIKE 7 (COL7) is involved in phytochrome B (phyB)-mediated light-quality regulation of auxin homeostasis.

Arabidopsis phytochrome B (phyB) is the major photoreceptor that senses the ratio of red to far-red light (R:FR) to regulate the shade-avoidance response (SAR). It has been hypothesized that altered homeostasis of phytohormones such as auxin and strigolactone is at least partially responsible for SAR, but the mechanism underlying phyB regulation of the hormonal change is not fully understood. Previously we reported that CONSTANS-LIKE 7 (COL7) enhances branching number under high R:FR but not under low R:FR, implying that COL7 may be involved in the phyB-mediated SAR. In this study, we provide evidence that COL7 reduces auxin levels in a high R:FR-dependent manner. We found that the phyB mutation suppresses the COL7-induced branching proliferation. Moreover, COL7 promotes mRNA expression of SUPERROOT 2 (SUR2), which encodes a suppressor of auxin biosynthesis, in high R:FR but not in low R:FR. Consistently with these results, deficiency of phyB suppresses the elevated transcription of SUR2 in COL7 overexpression plants grown in high R:FR. Taking these results together with data suggesting that photo-excited phyB is required for stabilization of the COL7 protein, we argue that COL7 is a critical factor linking light perception to changes in auxin level in Arabidopsis

Using High-Throughput Phenotyping Analysis to Decipher the Phenotypic Components and Genetic Architecture of Maize Seedling Salt Tolerance

Soil salinization is a worldwide problem that limits agricultural production. It is important to understand the salt stress tolerance ability of maize seedlings and explore the underlying related genetic resources. In this study, we used a high-throughput phenotyping platform with a 3D laser sensor (Planteye F500) to identify the digital biomass, plant height and normalized vegetation index under normal and saline conditions at multiple time points. The result revealed that a three-leaf period (T3) was identified as the key period for the phenotypic variation in maize seedlings under salt stress. Moreover, we mapped the salt-stress-related SNPs and identified candidate genes in the natural population via a genome-wide association study. A total of 44 candidate genes were annotated, including 26 candidate genes under normal conditions and 18 candidate genes under salt-stressed conditions. This study demonstrates the feasibility of using a high-throughput phenotyping platform to accurately, continuously quantify morphological traits of maize seedlings in different growing environments. And the phenotype and genetic information of this study provided a theoretical basis for the breeding of salt-resistant maize varieties and the study of salt-resistant genes