Dimensionality dependent electronic structure of the exfoliated van der Waals antiferromagnet NiPS3_3

Resonant Inelastic X-ray Scattering (RIXS) was used to measure the local electronic structure in few-layer exfoliated flakes of the van der Waals antiferromagnet NiPS$_3$. The resulting spectra show a systematic softening and broadening of $NiS_6$ multiplet excitations with decreasing layer count from the bulk to three atomic layers (3L). These trends are driven by a decrease in the transition metal-ligand and ligand-ligand hopping integrals, and in the charge-transfer energy: $\Delta$ = 0.60 eV in the bulk and 0.22 eV in 3L NiPS$_3$. Relevant intralayer magnetic exchange integrals computed from the electronic parameters exhibit a systematic decrease in the average interaction strength with thickness and place 2D NiPS$_3$ close to the phase boundary between stripy and spiral antiferromagnetic order, which may explain the apparent vanishing of long-range order in the 2D limit. This study explicitly demonstrates the influence of $inter$layer electronic interactions on $intra$layer ones in insulating magnets. As a consequence, the magnetic Hamiltonian in few-layer insulating magnets can be significantly different from that in the bulk.Comment: 5 pages, 4 figures; additional 9 pages and 13 figures of supplementary informatio

Modulation of innate immune responses at birth by prenatal malaria exposure and association with malaria risk during the first year of life.

BACKGROUND: Factors driving inter-individual differences in immune responses upon different types of prenatal malaria exposure (PME) and subsequent risk of malaria in infancy remain poorly understood. In this study, we examined the impact of four types of PME (i.e., maternal peripheral infection and placental acute, chronic, and past infections) on both spontaneous and toll-like receptors (TLRs)-mediated cytokine production in cord blood and how these innate immune responses modulate the risk of malaria during the first year of life. METHODS: We conducted a birth cohort study of 313 mother-child pairs nested within the COSMIC clinical trial (NCT01941264), which was assessing malaria preventive interventions during pregnancy in Burkina Faso. Malaria infections during pregnancy and infants' clinical malaria episodes detected during the first year of life were recorded. Supernatant concentrations of 30 cytokines, chemokines, and growth factors induced by stimulation of cord blood with agonists of TLRs 3, 7/8, and 9 were measured by quantitative suspension array technology. Crude concentrations and ratios of TLR-mediated cytokine responses relative to background control were analyzed. RESULTS: Spontaneous production of innate immune biomarkers was significantly reduced in cord blood of infants exposed to malaria, with variation among PME groups, as compared to those from the non-exposed control group. However, following TLR7/8 stimulation, which showed higher induction of cytokines/chemokines/growth factors than TLRs 3 and 9, cord blood cells of infants with evidence of past placental malaria were hyper-responsive in comparison to those of infants not-exposed. In addition, certain biomarkers, which levels were significantly modified depending on the PME category, were independent predictors of either malaria risk (GM-CSF TLR7/8 crude) or protection (IL-12 TLR7/8 ratio and IP-10 TLR3 crude, IL-1RA TLR7/8 ratio) during the first year of life. CONCLUSIONS: These findings indicate that past placental malaria has a profound effect on fetal immune system and that the differential alterations of innate immune responses by PME categories might drive heterogeneity between individuals to clinical malaria susceptibility during the first year of life

A monoclonal antibody which binds to the surface of chick brain cells and myotubes: cell selectivity and properties of the antigen

A monoclonal antibody has been obtained which binds to the cell surface of cultured chick myotubes and retinal and tectal neurons but not fibroblasts, myoblasts and embryonic liver cells. Indirect immunocytochemistry reveals that antigen is present in all layers of the chick neural retina. The antibody therefore recognizes an antigen common to most, if not all, chick neurons. The antigen has been identified by staining SDS gels with [125I]monoclonal antibody and appears to be a polydisperse collection of polypeptides with molecular weights centered about 250 kdalton

A comparative evaluation of oxygen consumption and gait pattern in amputees using Intelligent Prostheses and conventionally damped knee swing-phase control.

Objective: To compare the gait of amputees wearing conventionally damped pneumatic swing-phase control knees and microchip-controlled Intelligent Prostheses. Design: Crossover trial. Setting: An amputee rehabilitation centre in a teaching hospital. Participants: Ten established unilateral transfemoral prosthetic users were asked to participate in the trial; all agreed. Interventions: The amputees were assessed wearing pneumatic swing-phase control knees and then with the Intelligent Prosthesis. Main outcome measures: Oxygen consumption while walking at different speeds on a treadmill, video-recording of gait assessed by a panel and temporal-spatial parameters of gait whilst walking at slow, fast or normal speeds in a gait laboratory. Results: Mean oxygen cost for all subjects at 0.69 m/s was 0.33 ml/kg.m with the conventional limb and 0.30 ml/kg.m with the Intelligent Prosthesis (p 0.01). At 1.25 m/s the mean oxygen cost for the conventional limb was 0.24 ml/kg.m and for the Intelligent Prosthesis was 0.22 ml/kg.m (not significant). The ANOVA analysis showed that oxygen cost was similar at normal walking speeds but increased more at lower speeds for the pneumatic swing-phase control leg compared to the Intelligent Prosthesis (p &lt; 0.02). There were no significant differences in subjective gait evaluation or temporal and spatial gait parameters. Conclusion: At lower speeds oxygen cost was lower with the Intelligent Prosthesis. Gait analysis detected no significant changes between the two legs.</p