Magnetic dilution of a honeycomb lattice XY magnet CoTiO3

We report our study of cobalt (II) titanate, CoTiO3, in which magnetic Co ions are replaced by non-magnetic ions. The antiferromagnetic ordering transition of CoTiO3 around 37 K is described with ferromagnetic honeycomb layers coupled antiferromagnetically along the crystallographic c direction. The effect of magnetic dilution on the Néel temperature of this material is investigated through the doping of Zn2+ and Mg2+ in place of Co2+ for various dilution levels up to x + y = 0.46 in Co1-x-yZnxMgyTiO3. Single phase polycrystalline samples have been synthesized and their structural and magnetic properties have been examined. A linear relation between dilution and the Néel temperature is observed over a wide doping range. A linear extrapolation would suggest that the required dilution level to suppress magnetic order is around x + y ∽ 0.74, well beyond the classical percolation threshold. The implication of this observation for microscopic models for describing CoTiO3 is discussed.

Validation of the Use of Dried Blood Samples for the Detection of Toxoplasma gondii Antibodies in Stray Cats (Felis s. catus)

If validated beforehand, the analysis of dried blood on blotting paper (BP samples) is very useful for monitoring free-ranging animals. We aimed to validate this method for the detection of antibodies against Toxoplasma gondii in stray cats. We used the modified agglutination test (MAT) in 199 sample pairs of sera and BP samples from 54, 39, 56, and 50 cats trapped during four periods in five dairy farms. Screening was at 1:6, 1:12, and 1:24 dilutions. The cut-off value was at MAT titre ≥ 24, but MAT titre ≥ 12 was also considered for BP samples that often have a higher dilution level. Depending on the period, sample type, and cut-off value, sensitivity of the analysis of the BP sample vs. serum varied from 87.1% to 100% and specificity ranged from 72.22% to 100%. The concordance values and Kappa coefficient showed a substantial to excellent agreement between the results of the two methods, whatever the cut-off value. These findings quantifiably validate the use of MAT on BP samples for the detection of antibodies to T. gondii in stray cats, but we recommend expressing results from BP samples with several cut-off values as the MAT titres tend to be lower than those of sera.

Estratégias para o Desenvolvimento de Revestimentos Resistentes ao Desgaste: Uma Revisão

This review presents the possible strategies to increase the wear resistance of hardfacing alloys based on metallic matrix and second hard phase’s coupled design. As the wear resistance is not an intrinsic property of material, the results of many wear tests are discussed in light of the interaction between mechanical properties and wear severity, which is dependent on the microstructure. These strategies are based on the hardness increase, considering the kind and size of the second hard phase, the fracture toughness, and the dilution level of hardfacing. The guidelines provided for designing better the hardfacing alloys for usual abrasion conditions depending on the volume fraction of the second hard phase.

Sufficient Thrombin Generation Despite 95% Hemodilution: An In Vitro Experimental Study

Guidelines for the treatment of severe bleeding comprise viscoelastic-test-guided use of coagulation factor concentrates as part of their recommendations. The aim of this study is to investigate the effects of substituting fibrinogen, prothrombin complex concentrate, and a combination of both on conventional coagulation tests, viscoelastic test results, and thrombin generation. Blood was drawn from seven healthy volunteers to obtain platelet-free plasma, which later was diluted by replacing 40%, 60%, 80%, 90%, 95%, and 99% with a crystalloid solution. The diluted samples were spiked with fibrinogen concentrate, prothrombin complex concentrate, a combination of both, or a corresponding amount of crystalloid solution. Up to a dilution level of 95%, viscoelastically determined clotting time was significantly shorter in the group substituted with fibrinogen only in comparison with the additional use of prothrombin complex concentrate. Clot firmness and endogenous thrombin potential remained at relatively stable values up to a dilution level of 95% with the substitution of fibrinogen but not prothrombin complex concentrate. Substitution of prothrombin complex concentrate led to an excessive overshoot of thrombin generation. The results of our study question currently propagated treatment algorithms for bleeding patients that include the use of prothrombin complex concentrate for patients without former intake of oral anticoagulants. Even in severely bleeding patients, thrombin generation might be sufficient to achieve adequate hemostasis.

CUBOSOMES: A NOVEL DRUG DELIVERY SYSTEM OVERVIEW

Cubosomes are self-assembled, nanostructured, thermodynamically stable, square and rounded particles with cubic lattices visible. These are considered as versatile systems because of their properties and hence administrable in different ways such as orally, percutaneously, and parenterally. Cubosomes are organized in three dimensions as honey combed structures that are comprised of curved bicontinuous lipid bilayers which are divided into two internal aqueous channels that can be exploited by various bioactive ingredients, such as chemical drugs, peptides and proteins. Cubosomes can easily be incorporated into product formulations as they remain stable almost at any dilution level because of the relative insolubility of cubic phase forming lipid in water. This article gives an overview on structure, classification, properties, components, forms, preparation methods, evaluation and applications of cubosomes.

Utility of rapid plasmin reagin titres in assessing treatment response and re-infection for infectious syphilis

Background The rapid plasma reagin (RPR) assay is commonly used as a surrogate marker of infectious syphilis, but is non-specific, slow to change and variable in its rate of decline post treatment. Methods: Within an urban sexual health service testing predominantly men who have sex with men, a file review of RPR changes was undertaken in all subjects who had a dilution level of ≥1:4, between January 2015 to the end of December 2018. Results: Overall, 248 cases of infectious syphilis were identified in 215 subjects (165 HIV seropositive, 50 HIV seronegative). Among unique-subject cases with follow-up RPR recorded, seroreversion to a non-reactive titre was achieved in only 42.3% (71/168) cases at a median of 235 days (interquartile range: 138–348 days) and was significantly less likely if patients had HIV infection (P = 0.02), late latent syphilis (P = 0.003) or a subsequent syphilis infection (P < 0.0001). Having HIV infection (P = 0.03) or a subsequent episode of syphilis (P = 0.01) were associated with a lower likelihood of documented cure. Conclusions: The slow decay in RPR titres post therapy and the inability of a significant number of subjects to achieve a non-reactive result over time makes RPR a poor test for assessing the adequacy of treatment or in diagnosing re-infection, especially in populations having repeated and frequent risk exposures. As the number of syphilis cases continue to climb, better tests that accurately assess pathogen presence are urgently needed.