Enhancement of ferromagnetic correlations on multiferroic TbMnO₃ by replacing Mn with Co

The structural, electronic and magnetic properties of TbMn(1-x)Co(x)O(3) (0.1 ≤ x ≤ 0.9) compounds are reported. The samples are isostructural to TbMnO(3) adopting the orthorhombic distorted perovskite structure (Pbnm), except for x = 0.4, 0.5 and 0.6, where an ordered double perovskite structure (P2(1)/n) is found. X-ray absorption spectra at the Mn and Co K edges show an incomplete charge transfer between Mn and Co atoms yielding a mixed valence state Mn(3+)/Mn(4+) and Co(3+)/Co(2+) for the whole series. Neutron powder diffraction measurements show the development of a ferromagnetic ground state for the intermediate compositions (0.3 ≤ x ≤ 0.6) indicating that the ferromagnetic superexchange Mn(4+)-O-Co(2+) interaction is the strongest among a wide set of competitive interactions. The ferromagnetic ordering is, however, not fully achieved and coexists with glassy magnetic properties. With increasing concentration of Co (x ≥ 0.7) the long range ordering vanishes and only a glassy magnetic behavior with slow dynamics is found. These properties could be related to the existence of magnetically inhomogeneous small clusters arising from competitive magnetic interactions.

Template-assisted CoPd nanowire arrays: magnetic properties and FORC analysis

Highly hexagonally ordered CoPd alloy nanowire arrays were synthesized through electrochemical deposition techniques into the nanopores of anodic alumina membranes used as templates. Two different electrolytes were used for this purpose, one with pH = 4.1 and the other with pH = 7. Under applying different electrodeposition parameters and by adjusting both, the current density and the electrolyte composition, it could be possible make to vary the composition of CoPd alloy nanowires in a wide range. Their composition and morphology were investigated by SEM and EDX. The magnetic properties of the nanowires array have been measured with a VSM as a function of the temperature, ranging from RT down to 50 K, for different CoPd alloy nanowires composition. Also, the temperature influence on the reversible-irreversible magnetization processes related with the magnetization reversal of the CoPd nanowires array has been analyzed by first order reversal curve (FORC) method.

Structural properties of Pb2MnW(1-x)Re(x)O6 double perovskites

Pb2MnW(1-x)Re(x)O6 samples have been synthesized and their structure determined by powder x-ray diffraction. These samples undergo a first order structural phase transition between 413 and 445 K depending on the composition. Above this temperature, the samples are cubic. Below the transition temperature, solid solutions are found for x ≤ 0.2 and x ≥ 0.5. The W-rich samples adopt an orthorhombic cell whereas the Re-rich compounds are monoclinic. In the intermediate region, 0.2 < x < 0.5, both phases coexist. X-ray absorption spectra did not reveal significant changes in the local structure for Pb, Mn or Re atoms across the structural phase transition. All the atoms exhibit distorted environments in the whole series. In the case of Pb and W(Re) atoms, the local distortion remains in the high temperature phase. Samples with x ≤ 0.2 also show a sharp discontinuity in the dielectric permittivity at the phase transition temperature indicating the presence of a concomitant electrical ordering in the bulk grains. Such an anomaly in the dielectric constant is not observed for the x ≥ 0.5 samples, compatible with the lack of dipole ordering for this composition range. The different electrical behaviours also explain the differences in the entropy content for the two types of transition.

The transition from ferromagnet to cluster-glass in La(1-x)Tb(x)Mn1/2Sc1/2O3

We report the structural and magnetic properties of the La(1-x)Tb(x)Mn(1/2)Sc(1/2)O(3) series. LaMn(1/2)Sc(1/2)O(3) shows a long range ferromagnetic ordering in agreement with a fully polarized Mn-sublattice. The substitution of La with Tb produces structural changes which affect the magnetic properties. This substitution leads to a contraction in the unit cell volume that mainly reduces the M-O-M bond angle (M = Mn, Sc). The bending of this angle decreases the Mn-O-Mn superexchange interaction and enhances the competition between nearest-neighbour and next-nearest-neighbour interactions. Accordingly, the magnetic ground state changes from ferromagnetic to a glassy magnetic state. Large thermal irreversibility between zero-field-cooled and field-cooled conditions is observed for all samples. The study of the dynamic magnetic properties has been performed using the frequency dependent real part of the ac magnetic susceptibility. The use of both the Vogel-Fulcher law and the conventional critical slowing down law yields similarly good accuracies in the fits. The relaxation times obtained from both laws concur with the existence of a cluster-glass for x ≥ 0.5 samples.

Software development for the evaluation of the ergonomic compatibility on the selection of advanced manufacturing technology

Advanced Manufacturing Technology (AMT) is one of the most relevant resources that companies have to achieve competitiveness and best performance. The selection of AMT is a complex problem which involves significant amount of information and uncertainty when multiple aspects must be taken into consideration. Actual models for the selection of AMT are found scarce of the Human Factors and Ergonomics perspective which can lead to a more complete and reliable decision. This paper presents the development of software that enhances the application of an Ergonomic Compatibility Evaluation Model that supports decision making processes taking into consideration ergonomic attributes of designs. Ergonomic Compatibility is a construct used in this model and it is mainly based in the concept of human-artifact compatibility on human compatible systems. Also, an Axiomatic Design approach by the use of the Information Axiom was evolved under a fuzzy environment to obtain the Ergonomic Incompatibility Content. The extension of this axiom for the evaluation of ergonomic compatibility requirements was the theoretical framework of this research. An incremental methodology of four stages was used to design and develop the software that enables to compare AMT alternatives by the evaluation of Ergonomic Compatibility Attributes.

[Relationship between the alveolar-arterial oxygen gradient and PaO₂/FiO₂-introducing PEEP into the model]

OBJECTIVES

To determine whether the alveolar-arterial oxygen gradient (Grad[A-a]O₂) helps confirm the influence of PEEP on PaFi (PaO₂/FiO₂).

DESIGN

Observational study; we used linear regression to perform a multivariate study to improve the PaFi formula by taking PEEP into account.

SETTING

Tertiary hospital.

PATIENTS

We included all patients who were admitted to the intensive care unit, regardless of pulmonary damage.

VARIABLES

We recorded personal history, clinical judgment, intensive care data, severity scores on the first day and progression. Two calculated variables: PaFi and Grad(A-a)O₂.

RESULTS

A total of 956 patients were included: 63.9% men; median age 68 years. On the first day, 31.8% did not have mechanical ventilation (MV), 13.1% had non-invasive MV and 55.1% had invasive MV. PaFi values: 32.9% 0-200, 32.2% 201-300, and 34.8% >300. PEEP values: 0-5 69.8%, 6-10 27.5% and >10 2.6%. We observed a correlation (Pearson) between Grad(A-a)O₂ and PaFi of -0.84 (p<0.001). On performing multiple regression (dependent variable: Grad[A-a]O₂), the following variables were included in the model: PaFi, PEEP, APACHE IV and SOFA; coefficient of determination (R²) of 0.62 without PEEP and 0.72 with PEEP. We changed the PaFi formula, referring to it as PaFip (PaFi plus PEEP): Ln (PaFi/[PEEP+12]). Correlation index between PaFip and Grad(A-a)O₂: -0.9 (p<0.001). We performed linear regression (dependent variable: Grad[A-a]O₂) and used PaFip instead of PaFi. Only PaFi remained in the model, and was discretely complemented by APACHE IV; R²=0.8.

CONCLUSIONS

By adding PEEP to the PaFi model (PaFip), we clearly improve the latter, as reflected by a better goodness of fit.

Origin of the pre-peak features in the oxygen K-edge x-ray absorption spectra of LaFeO₃ and LaMnO₃ studied by Ga substitution of the transition metal ion

We report on experimental oxygen K-edge x-ray absorption near edge structure (XANES) spectra of the LaFe(1 - x)Ga(x)O(3) and LaMn(1 - x)Ga(x)O(3) series. Transition metal substitution by the 3d full shell Ga atom is mainly reflected in a systematic decrease of the pre-edge structures in the XANES spectra of the two series. This result shows that the associated states originate from the hybridization of oxygen 2p and unoccupied Fe (or Mn) 3d states. In order to gain insight into the states associated with the pre-edge spectral features, we have performed ab initio theoretical calculations based on multiple scattering theory. Simulations with variable cluster size and composition around the absorber oxygen in the LaFeO(3) and LaMnO(3) crystal structures were carried out. We find that the low-energy pre-peak is reproduced once the absorbing oxygen and the two nearest neighbour Fe (or Mn) ions are considered in the cluster. Conversely, higher energy pre-peaks only arise when the full oxygen coordination geometry around the two metal sites is taken into account, implying that their energy distance is a reflection of the strength of the oxygen ligand field. Substitutions of the two nearest neighbours by Ga atoms in the cluster of calculation lead to changes in the theoretical spectra that reasonably agree with the evolution of the pre-peaks in the experimental XANES spectra of both the series.

CB.Hep-1 hybridoma growth and antibody production using protein-free medium in a hollow fiber bioreactor

The protein-free medium TurboDoma HP.1 (THP.1) was used to produce the CB.Hep-1 monoclonal antibody (mAb) in a CP-1000 hollow fiber bioreactor (HFB). This mAb is used for the immunopurification of recombinant hepatitis B surface antigen (rHBsAg), which is included in a vaccine preparation against the Hepatitis B Virus. By using the experimental conditions tested in this work we were able to generate more than 433 mg of IgG in 43 days. The maximum antibody concentration obtained was about 2.4 mg ml(-1)and the IgG production per day was approximately 11 mg of monoclonal antibody, which constitutes a good concentration value in comparison to the results obtained in ascitic fluid, where concentration for this hybridoma was around 3 mg ml(-1). We used different analytical methods to control the quality of mAbs, obtained from the in vitro system. They included affinity constant determination, analysis of N-glycan structures, immunoaffinity chromatography and antigen binding properties. The results obtained suggest that no significant changes occurred in the mean characteristics of the mAb harvested from the bioreactor during the 43 days of cultivation.

Misdiagnosis and psychotic symptoms in bipolar disorder

Introduction

Early onset forms of bipolar disorder may be difficult to distinguish from schizophrenia. Although operational criteria have become more precise, and there are more diagnostic systems to catalogue a psychotic adolescent, the clinicians continue having difficulties.

Objective

To know the stability of the diagnosis of definitively bipolar patients with psychotic symptoms during the episodes, and factors that can influence other psychotic diagnoses in the first episode of the illness.

Method

140 bipolar patients of Araba, (Basque country) were included during 2 years. Patients were divided into two groups: unstable diagnoses (UD)(bipolar patients with an initial diagnosis of other psychosis) and stable diagnoses (SD) of bipolar disorder. Clinical and sociodemographic data were obtained.

Results

The mean age at onset was significantly lower in the UD group (p = 0.004). It was rare to have an unstable diagnosis when the first psychotic episode occurred after age 38 (p = 0.008). There were more singles in the UD group (p = 0.010).

The presence of mood incongruent psychotic symptoms was more frequent in the UD group (p < 0.001).

Mood incongruent psychotic symptoms variable was the only independent factor significantly associated with an unstable diagnosis in the multivariate analysis (p = 0.036).

Discussion

One third of the patients have been previously diagnosed with other psychotic illness.

This study suggests that the most important factor is the clinical picture, especially the presence of mood-incongruent psychotic symptoms. A correct diagnosis is important because patients who are prescribed mood stabilizers have lower rates of rehospitalisation than those who are not treated with mood stabilizers.

Influence of design, physico-chemical and environmental parameters on pharmaceuticals and fragrances removal by constructed wetlands

The ability of several mesocosm-scale and full-scale constructed wetlands (CWs) to remove pharmaceuticals and personal care products (PPCPs) from urban wastewater was assessed. The results of three previous works were considered as a whole to find common patterns in PPCP removal. The experiment took place outdoors under winter and summer conditions. The mesocosm-scale CWs differed in some design parameters, namely the presence of plants, the vegetal species chosen (Typha angustifolia versus Phragmites australis), the flow configuration (surface flow versus subsurface flow), the primary treatment (sedimentation tank versus HUSB), the feeding regime (batch flow versus continuous saturation) and the presence of gravel bed. The full-scale CWs consisted of a combination of various subsystems (ponds, surface flow CWs and subsurface flow CWs). The studied PPCPs were ketoprofen, naproxen, ibuprofen, diclofenac, salicylic acid, carbamazepine, caffeine, methyl dihydrojasmonate, galaxolide and tonalide. The performance of the evaluated treatment systems was compound dependent and varied as a function of the CW-configuration. In addition, PPCP removal efficiencies were lower during winter. The presence of plants favoured naproxen, ibuprofen, diclofenac, salicylic acid, caffeine, methyl dihydrojasmonate, galaxolide and tonalide removal. Significant positive correlations were observed between the removal of most PPCPs and temperature or redox potential. Accordingly, microbiological pathways appear to be the most likely degradation route for the target PPCPs in the CWs studied.