在600～800℃低氧压下Fe－Nb合金的氧化

研究了Ｆｅ－１５Ｎｂ和Ｆｅ－３０Ｎｂ（Ｗｔ％）合金在６００～８００℃低氧压气氛中的氧化行为，实验所用的氧压处于煤的气化气氛下的氧分压范围。氧化后合金仅发生了Ｎｂ的内氧化，生成Ｎｂ２与Ｎｂ２Ｏ５，有些情况下还生成ＦｅＮｂ２Ｏ６。在６００℃时氧化速度很低，但在７００～８００℃时则颇高。这些合金内氧化的重要特征之一，是其内氧化物的分布几乎完全与合金中的高含Ｎｂ相一致。此外，合金氧化后均不出现外氧化层。这些可能都是由于Ｎｂ在Ｆｅ中溶解度很低且合金呈两相组织所致。     

Lack of Association of Estrogen Receptor Alpha Gene Polymorphisms with Cardiorespiratory and Metabolic Variables in Young Women

This study examined the association of estrogen receptor alpha gene (ESR1) polymorphisms with cardiorespiratory and metabolic parameters in young women. In total, 354 healthy women were selected for cardiopulmonary exercise testing and short-term heart rate (HR) variability (HRV) evaluation. The HRV analysis was determined by the temporal indices rMSSD (square root of the mean squared differences of successive R–R intervals (RRi) divided by the number of RRi minus one), SDNN (root mean square of differences from mean RRi, divided by the number of RRi) and power spectrum components by low frequency (LF), high frequency (HF) and LF/HF ratio. Blood samples were obtained for serum lipids, estradiol and DNA extraction. ESR1 rs2234693 and rs9340799 polymorphisms were analyzed by PCR and fragment restriction analysis. HR and oxygen uptake (VO₂) values did not differ between the ESR1 polymorphisms with respect to autonomic modulation. We not find a relationship between ESR1 T–A, T–G, C–A and C–G haplotypes and cardiorespiratory and metabolic variables. Multiple linear regression analysis demonstrated that VO₂, total cholesterol and triglycerides influence HRV (p < 0.05). The results suggest that ESR1 variants have no effect on cardiorespiratory and metabolic variables, while HRV indices are influenced by aerobic capacity and lipids in healthy women.     

Dehydration of bacterial cellulose and the water content effects on its viscoelastic and electrochemical properties

Bacterial cellulose (BC) has interesting properties including high crystallinity, tensile strength, degree of polymerisation, water holding capacity (98%) and an overall attractive 3D nanofibrillar structure. The mechanical and electrochemical properties can be tailored upon incomplete BC dehydration. Under different water contents (100, 80 and 50%), the rheology and electrochemistry of BC were evaluated, showing a progressive stiffening and increasing resistance with lower capacitance after partial dehydration. BC water loss was mathematically modelled for predicting its water content and for understanding the structural changes of post-dried BC. The dehydration of the samples was determined via water evaporation at 37 °C for different diameters and thicknesses. The gradual water evaporation observed was well-described by the model proposed (R² up to 0.99). The mathematical model for BC water loss may allow the optimisation of these properties for an intended application and may be extendable for other conditions and purposes.     

The use of wireless networks for the surveillance and control of cooperative vehicles in an airport

The paper focusses on the use of wireless networks, with special emphasis on Wi-Fi, in the manoeuvering and apron areas of an airport to control the ground vehicles movements in those areas and, consequently, to improve user safety, efficiency of operations and airport safety. The use of Wi-Fi for these purposes constitutes a novel approach in an airport environment. Other wireless networks, namely CDMA and TETRA, are also experimented in this project as lower bit-rate alternatives to Wi-Fi. The platform, which follows the Eurocontrol recommendations for A-SMGCS, consists of an on-board system in each vehicle, a centralised ground system and wireless networks to allow the communication between the vehicles and ground system. The architecture, protocols and network configurations in use are analysed as well as the deployment made in the airport of Porto in Portugal and the respective network performance results.     

COVID-19 Lockdowns May Reduce Resistance Genes Diversity in the Human Microbiome and the Need for Antibiotics

Recently, much attention has been paid to the COVID-19 pandemic. Yet bacterial resistance to antibiotics remains a serious and unresolved public health problem that kills hundreds of thousands of people annually, being an insidious and silent pandemic. To contain the spreading of the SARS-CoV-2 virus, populations confined and tightened hygiene measures. We performed this study with computer simulations and by using mobility data of mobile phones from Google in the region of Lisbon, Portugal, comprising 3.7 million people during two different lockdown periods, scenarios of 40 and 60% mobility reduction. In the simulations, we assumed that the network of physical contact between people is that of a small world and computed the antibiotic resistance in human microbiomes after 180 days in the simulation. Our simulations show that reducing human contacts drives a reduction in the diversity of antibiotic resistance genes in human microbiomes. Kruskal–Wallis and Dunn’s pairwise tests show very strong evidence (p < 0.000, adjusted using the Bonferroni correction) of a difference between the four confinement regimes. The proportion of variability in the ranked dependent variable accounted for by the confinement variable was η² = 0.148, indicating a large effect of confinement on the diversity of antibiotic resistance. We have shown that confinement and hygienic measures, in addition to reducing the spread of pathogenic bacteria in a human network, also reduce resistance and the need to use antibiotics.     

Photoactive Zn(II)Porphyrin–multi-walled carbon nanotubes nanohybrids through covalent β-linkages

Donor–acceptor nanohybrids by a covalent linkage between the β-position of a Zn(II)Porphyrin and multi-walled carbon nanotubes are reported for the first time, in a closer analogy to the natural light harvesting systems, which are based on β-substituted porphyrinoid structures, the chlorophylls. An unique and direct connection was established through the immobilization of the Zn(II)(β-NH₂-tetraphenylporphyrin), using diazonium chemistry, in order to afford i) a short and conjugated linkage between the two aromatic systems and ii) an amide bond resulting from a three-step functionalization synthesis. Electronic and steady-state fluorescence spectroscopies confirmed high photoinduced electron communication through the β-linkage when compared to analogous meso-phenyl linkers, stating its positive effect. The procedure involving the amide linkage allowed higher chromophore loadings; however, the direct conjugated bond showed improved photoinduced activity and a different emission pattern that can be associated with intense communication within the expanded π-system MWCNT–metalloporphyrin.     

Selective recognition in potentiometric transduction of amoxicillin by molecularly imprinted materials

The indiscriminate use of antibiotics in food-producing animals has received increasing attention as a contributory factor in the international emergence of antibiotic-resistant bacteria (Woodward in Pesticide, veterinary and other residues in food, CRC Press, Boca Raton, 2004). Numerous analytical methods for quantifying antibacterial residues in edible animal products have been developed over years (Woodward in Pesticide, veterinary and other residues in food, CRC Press, Boca Raton, 2004; Botsoglou and Fletouris in Handbook of food analysis, residues and other food component analysis, Marcel Dekker, Ghent, 2004). Being Amoxicillin (AMOX) one of those critical veterinary drugs, efforts have been made to develop simple and expeditious methods for its control in food samples. In literature, only one AMOX-selective electrode has been reported so far. In that work, phosphotungstate:amoxycillinium ion exchanger was used as electroactive material (Shoukry et al. in Electroanalysis 6:914–917, 1994). Designing new materials based on molecularly imprinted polymers (MIPs) which are complementary to the size and charge of AMOX could lead to very selective interactions, thus enhancing the selectivity of the sensing unit. AMOX-selective electrodes used imprinted polymers as electroactive materials having AMOX as target molecule to design a biomimetic imprinted cavity. Poly(vinyl chloride), sensors of methacrylic acid displayed Nernstian slopes (60.7 mV/decade) and low detection limits (2.9 × 10⁻⁵ mol/L). The potentiometric responses were not affected by pH within 4–5 and showed good selectivity. The electrodes were applied successfully to the analysis of real samples.     

Using virtual reality to study the effect of information redundancy on evacuation effectiveness

The International Organization for Standardization evacuation alarm (ISO 8201: 2017) is ineffective in initiating evacuation, particularly when people are engaged in pre-evacuation activities, and it is not easy to conduct experiments for evaluating evacuation behavior due to ethical and cost issues. A virtual building emergency where alarms went off while participants were performing activities was created to study the effect of redundancy on evacuation effectiveness. Three alarms were studied: (i) a regular nonverbal ISO alarm, (ii) a speech-inserted ISO alarm, and (iii) a technology-based ISO alarm concept (sound, visual, and haptic information). Evacuation behavior, perceived urgency, and delay time were measured. Results confirmed the effect of redundancy on measurements, and participants complied better with the speech-inserted and technology-based alarms, but there were no differences in evacuation effectiveness between them. Participants perceived higher urgency from the technology-based solution, which can be more adaptive in complicated environments where background noise and language/education barriers are problems. Otherwise, the speech-inserted alarm is more cost-effective.     

Indoor Human Wayfinding Performance Using Vertical and Horizontal Signage in Virtual Reality

Disorientation has many costs. It may lead to physical fatigue, stress, and frustration and can also jeopardize people's safety. Designing wayfinding aids to fit people's needs can facilitate their environmental knowledge acquisition and, therefore, improve their wayfinding performance. The scope of this article is human wayfinding in unfamiliar buildings, considering only individual pedestrian movement in an immersive virtual environment. The purpose is to investigate the use of external information at a higher level of awareness (e.g., signage) as a wayfinding aid, as well as the use of immersive virtual reality (VR) to study indoor wayfinding. Fifty‐four volunteers accomplished a wayfinding task (i.e., finding a room from the building's entrance) within a virtual building, employing two types of signage systems (i.e., vertical and horizontal conditions). A neutral condition (no signage) was also considered as a control condition to be used as a baseline. Aside from the success of the wayfinding task (getting to the destination), other performance metrics (distance traveled, time spent, number of pauses, and average speed) were analyzed and compared. Although the differences found are not statistically significant, findings suggest that participants assigned to the horizontal condition traveled smaller distances, spent less time, made fewer pauses, and moved at higher average speed than those assigned to vertical and neutral conditions. Gender‐related differences were found statistically significant only in the average speed variable (females were faster than males). © 2012 Wiley Periodicals, Inc.