Bistability, softening, and quenching of magnetic moments in Ni-filled carbon nanotubes

The authors apply first-principles calculations to investigate the interplay between structural, electronic, and magnetic properties of nanostructures composed of narrow nanotubes filled with metallic nanowires. The focus is on the structural and magnetic responses of Ni-filled nanotubes upon radial compression. Interestingly, metastable flattened structures are identified, in which radially deformed nanotubes are stabilized by the interactions with the encapsulated wire. Moreover, our results indicate a quenching of the magnetic moment of the wire upon compression, as a result of the transfer of charge from the $s$ to the $d$ orbitals of the atoms in the wire.Comment: 4 pages, 4 figure

South American Expert Roundtable : increasing adaptive governance capacity for coping with unintended side effects of digital transformation

This paper presents the main messages of a South American expert roundtable (ERT) on the unintended side effects (unseens) of digital transformation. The input of the ERT comprised 39 propositions from 20 experts representing 11 different perspectives. The two-day ERT discussed the main drivers and challenges as well as vulnerabilities or unseens and provided suggestions for: (i) the mechanisms underlying major unseens; (ii) understanding possible ways in which rebound effects of digital transformation may become the subject of overarching research in three main categories of impact: development factors, society, and individuals; and (iii) a set of potential action domains for transdisciplinary follow-up processes, including a case study in Brazil. A content analysis of the propositions and related mechanisms provided insights in the genesis of unseens by identifying 15 interrelated causal mechanisms related to critical issues/concerns. Additionally, a cluster analysis (CLA) was applied to structure the challenges and critical developments in South America. The discussion elaborated the genesis, dynamics, and impacts of (groups of) unseens such as the digital divide (that affects most countries that are not included in the development of digital business, management, production, etc. tools) or the challenge of restructuring small- and medium-sized enterprises (whose service is digitally substituted by digital devices). We identify specific issues and effects (for most South American countries) such as lack of governmental structure, challenging geographical structures (e.g., inclusion in high-performance transmission power), or the digital readiness of (wide parts) of society. One scientific contribution of the paper is related to the presented methodology that provides insights into the phenomena, the causal chains underlying “wanted/positive” and “unwanted/negative” effects, and the processes and mechanisms of societal changes caused by digitalization

Influence of autonomic control on the specific intermittent performance of judo athletes

Judo is a high-intensity intermittent combat sport which causes cardiac adaptations both morphologically and related to the autonomic nervous system (ANS). Therefore, this study aims to verify the correlation between heart rate variability (HRV) at rest with performance in the Special Judo Fitness Test (SJFT) and whether groups with different RR values at rest show different performance in the SJFT and during post-test recovery. Sixteen judo athletes with 7.2 +/- 3.9 years of training experience participated in the study. Before and after the SJFT execution HRV and lactate measurements were conducted. For HRV analysis, we used the mean interval RR, the standard deviation of the RR interval (SDNN), the root mean square of successive differences in RR intervals (RMSSD), the low frequency (LF) and high frequency (HF) in normalized and absolute units. The sample was split into two groups (low RR and high RR) to verify if this variable could differentiate between specific performance. For the SDNN, a significant and moderate correlation (r = 0.53) was found with the total number of throws and throws in the series A (r = 0.56) and B (r = 0.54) and for the RMSSD a correlation with throws during series B (r = 0.59) in the SJFT. However, the groups did not differ in performance and recovery. Therefore, HRV is related to intermittent judo performance; however, it cannot differentiate between judokas at different levels of performance

High mobility group box 1 levels in large vessel vasculitis are not associated with disease activity but are influenced by age and statins

Introduction: Takayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV. Methods: Twenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay. Results: In GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 +/- 4.19 ng/ml vs. 4.17 +/- 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45-2.10) ng/ml vs. 1.46 (0.89-3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63-2.16) ng/ml vs. 0.75 (0.39-2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29-1.46) ng/ml vs. 1.93 (0.88-3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status. Conclusions: Patients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV

The influence of Fe2O3 doping on the pore structure and mechanical strength of TiO2-containing alumina obtained by freeze-casting

This work investigated TiO/FeO doped alumina prepared by the freeze-casting technique and using camphene as the solvent. Dendritic pores were formed in the TiO doped alumina, a structure conferred by the frozen camphene. Contrary to this trend, further FeO doping of TiO-containing alumina resulted in the formation of non-dendritic structures. This behavior was attributed to the higher density of α-FeO (5.24 g cm) when compared to α-AlO (3.95 g cm) and anatase TiO (3.89 g cm), which reduced critical solidification front velocity, thus forming material with different pore shape. FeO doping also improved the densification of TiO-alumina and inhibited the formation of cracks, reflected by superior mechanical strength with best results ∼150% higher for 10% FeO loaded samples as compared to TiO-alumina samples

Effect of titania addition on the properties of freeze-cast alumina samples

This work investigated the behavior of TiO2-containing α-Al2O3 samples prepared by the freeze-casting technique. Camphene and liquid nitrogen were used as the solvent and cooling fluid, respectively. Camphene resulted in the formation of dendritic pores, in the direction of the freeze-casting cold front during sample preparation. The formation of β-Al2TiO5 phase occurred at 1300°C, and became more evident as the sintering temperatures reached 1500°C. The TiO2 loading did not affect the sample porosity at a given temperature, but it was detrimental in the case of mechanical properties under certain conditions. For instance, the flexural strength slightly improved with increasing the TiO2 loading and sintering temperature from 1100 to 1300°C. This effect was attributed to the occurrence of a more effective sintering of alumina. However, as the heat treatment temperature was raised from 1300 to 1500°C, the flexural strength did not increase as a function of the TiO2 loading, even though the densification occurred with loss of porosity. The loss of mechanical strength was found to be associated with the formation of microcracks which stemmed from the formation of β-Al2TiO5 phase for TiO2 loadings in excess of 4wt% at these high sintering temperatures