Wetting, the process of water interacting with a surface, is critical in our everyday lives and in many biological and technological systems. The contact angle is the angle at the interface where ...water, air and solid meet, and its value is a measure of how likely the surface is to be wetted by the water. Low contact-angle values demonstrate a tendency of the water to spread and adhere to the surface, whereas high contact-angle values show the surface's tendency to repel water. The most common method for surface-wetting characterization is sessile-drop goniometry, due to its simplicity. The method determines the contact angle from the shape of the droplet and can be applied to a wide variety of materials, from biological surfaces to polymers, metals, ceramics, minerals and so on. The apparent simplicity of the method is misleading, however, and obtaining meaningful results requires minimization of random and systematic errors. This article provides a protocol for performing reliable and reproducible measurements of the advancing contact angle (ACA) and the receding contact angle (RCA) by slowly increasing and reducing the volume of a probe drop, respectively. One pair of ACA and RCA measurements takes ~15-20 min to complete, whereas the whole protocol with repeat measurements may take ~1-2 h. This protocol focuses on using water as a probe liquid, and advice is given on how it can be modified for the use of other probe liquids.
NH3-Selective Catalytic Reduction (NH3-SCR) is a widely used technology for NO x reduction in the emission control systems of heavy duty diesel vehicles. Copper-based ion exchanged zeolites and in ...particular Cu-SSZ-13 (CHA framework) catalysts show both exceptional activity and hydrothermal stability for this reaction. In this work, we have studied the origin of the SCR activity of Cu-SSZ-13 as evidenced from a combination of synchrotron-based and laboratory techniques. Synchrotron-based in situ XAFS/XRD measurements were used to provide complementary information on the local copper environment under realistic NH3-SCR conditions. Crucial then to the catalytic activity of Cu-SSZ-13 is the local environment of the copper species, particularly in the zeolite. Cu-SSZ-13 contains mononuclear Cu2+ species, located in the face of the double-6-ring subunit of the zeolite after calcination where it remains under reaction conditions. At lower temperatures (with low activity), XAFS and XRD data revealed a conformational change in the local geometry of the copper from a planar form toward a distorted tetrahedron as a result of a preferential interaction with NH3. This process appears necessary for activity, but results in a stymieing of activity at low temperatures. At higher temperatures, the Cu2+ possess a local coordination state akin to that seen after calcination.
Nature offers exciting examples for functional wetting properties based on superhydrophobicity, such as the self-cleaning surfaces on plant leaves and trapped air on immersed insect surfaces allowing ...underwater breathing. They inspire biomimetic approaches in science and technology. Superhydrophobicity relies on the Cassie wetting state where air is trapped within the surface topography. Pressure can trigger an irreversible transition from the Cassie state to the Wenzel state with no trapped air—this transition is usually detrimental for nonwetting functionality and is to be avoided. Here we present a new type of reversible, localized and instantaneous transition between two Cassie wetting states, enabled by two-level (dual-scale) topography of a superhydrophobic surface, that allows writing, erasing, rewriting and storing of optically displayed information in plastrons related to different length scales.
The gap between students' formal, school-based learning and informal, social learning has been widely acknowledged. To overcome this gap, academic service-learning (AS-L) pedagogy involves deliberate ...efforts to interconnect formal and informal learning by enhancing students' transitions across multiple authentic settings and fostering their participation in various social roles. The aim of this study was to examine how AS-L is practiced among Finnish primary and secondary schools, what kind of stakeholder networks are involved, what the experienced outcomes are, and which factors enable the AS-L pedagogy to be embedded into the Finnish formal school context. The data consisted of semi-structured educator interviews describing nine cases of implementing AS-L practices in diverse Finnish school settings. Empirically driven, thematic data-analysis generated an overall description of the AS-L pedagogies examined. The findings confirm that AS-L pedagogy fulfiled the curricular aims, assisted in meeting the learning objectives and affirmed the fundamental role of external stakeholders in AS-L pedagogy. However, results also revealed challenges related to schools' operational infrastructures, lesson frameworks, and teacher collaboration hindering the interdisciplinary implementation of AS-L pedagogy, preventing synergies with subject-specific learning contents, and limiting stakeholder networks. Innovative teacher activity, in turn, was identified as a success factor in applying AS-L pedagogy. The results indicate that interconnecting formal and informal learning requires schools' systemic change, and furthermore, legitimising teacher's transformative efforts fosters development and implementation of novel pedagogical practices.
Summary
Pla of the plague bacterium Yersinia pestis and PgtE of the enteropathogen Salmonella enterica are surface‐exposed, transmembrane β‐barrel proteases of the omptin family that exhibit a ...complex array of interactions with the hemostatic systems in vitro, and both proteases are established virulence factors. Pla favors fibrinolysis by direct activation of plasminogen, inactivation of the serpins plasminogen activator inhibitor‐1 and α2‐antiplasmin, inactivation of the thrombin‐activable fibrinolysis inhibitor, and activation of single‐chain urokinase. PgtE is structurally very similar but exhibits partially different functions and differ in expression control. PgtE proteolysis targets control aspects of fibrinolysis, and mimicry of matrix metalloproteinases enhances cell migration that should favor the intracellular spread of the bacterium. Enzymatic activity of both proteases is strongly influenced by the environment‐induced variations in lipopolysaccharide that binds to the β‐barrel. Both proteases cleave the tissue factor pathway inhibitor and thus also express procoagulant activity.
The relationship between smoking and suicide remains controversial.
A total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking ...questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case-control design.
Smokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31-5.22 than light smokers (HR 2.30, 95% CI 1.61-3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43-4.59), adjusting for depressive symptoms, alcohol and sedative-hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers odds ratio (OR) 6.0, 95% CI 2.06-23.8.
Adults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.
Hollow nano-objects have raised interest in applications such as sensing, encapsulation, and drug-release. Here we report on a new class of porous materials, namely inorganic nanotube aerogels that, ...unlike other aerogels, have a framework consisting of inorganic hollow nanotubes. First we show a preparation method for titanium dioxide, zinc oxide, and aluminum oxide nanotube aerogels based on atomic layer deposition (ALD) on biological nanofibrillar aerogel templates, that is, nanofibrillated cellulose (NFC), also called microfibrillated cellulose (MFC) or nanocellulose. The aerogel templates are prepared from nanocellulose hydrogels either by freeze-drying in liquid nitrogen or liquid propane or by supercritical drying, and they consist of a highly porous percolating network of cellulose nanofibrils. They can be prepared as films on substrates or as freestanding objects. We show that, in contrast to freeze-drying, supercritical drying produces nanocellulose aerogels without major interfibrillar aggregation even in thick films. Uniform oxide layers are readily deposited by ALD onto the fibrils leading to organic−inorganic core−shell nanofibers. We further demonstrate that calcination at 450 °C removes the organic core leading to purely inorganic self-supporting aerogels consisting of hollow nanotubular networks. They can also be dispersed by grinding, for example, in ethanol to create a slurry of inorganic hollow nanotubes, which in turn can be deposited to form a porous film. Finally we demonstrate the use of a titanium dioxide nanotube network as a resistive humidity sensor with a fast response.
Due to faster recovery and lower morbidity rates, laparoscopy has become the gold standard in elective colorectal surgery for both the benign and malignant forms of the disease. A substantial ...proportion of colorectal operations are, however, carried out in emergency settings, and most of the emergency resections are still performed open. The aim of this study is to compare the laparoscopic versus open approach for emergency colorectal surgery.
This is a multicenter prospective randomized controlled trial including adult patients presenting with a condition requiring emergency colorectal resection.
Previous studies cautiously recommend wider use of laparoscopy in emergency colorectal resections, but all earlier reports are retrospective, are mostly single-center studies, and have limited numbers of patients. Laparoscopy may involve some unpredictable risks that have not yet been reported because of the infrequent use of the techniqueded to assess the safety of laparoscopy as well as the advantages and disadvantages of open compared with laparoscopic emergency surgery.
Trial registration number: ClinicalTrials.gov NCT05005117 . Registered on August 12, 2021.
In this study, polyimide/graphene nanocomposite films which exhibited significant enhancements in mechanical properties and electrical conductivity were successfully fabricated. Graphene oxide (GO) ...synthesized by Hummer’s method was chemically modified with ethyl isocyanate to give ethyl isocyanate-treated graphene oxide (iGO), which is readily dispersed in N,N′-dimethylformamide (DMF). The iGO dispersion in DMF was then used as media for synthesis of polyimide/functionalized graphene composites (PI/FGS) by an in situ polymerization approach. It was shown that addition of only 0.38 wt% of FGS, Young’s modulus of the PI/FGS composite film was dramatically increased from 1.8 GPa to 2.3 GPa, which is approximately 30% of improvement compared to that of pure PI film, and the corresponding tensile strength was increased from 122 MPa to 131 MPa. In addition, the electrical conductivity of the PI/FGS with this graphene content was increased by more than eight orders of magnitude to 1.7 × 10
−5 S m
−1.
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Because sustained physical activity is important for a healthy life, this paper examined whether a greater diversity of sport activities during adolescence predicts higher levels of leisure‐time ...physical activity (LTPA) in adulthood. From sport activity participation reported by 17‐year‐old twins, we formed five groups: 1, 2, 3, 4, and 5+ different sport activities. At follow‐up in their mid‐thirties, twins were divided into four activity classes based on LTPA, including active commuting. Multinomial regression analyses, adjusted for several confounders, were conducted separately for male (N=1288) and female (N=1770) participants. Further, conditional logistic regression analysis included 23 twin pairs discordant for both diversity of sport activities in adolescence and LTPA in adulthood. The diversity of leisure‐time sport activities in adolescence had a significant positive association with adulthood LTPA among females. Membership in the most active adult quartile, compared to the least active quartile, was predicted by participation in 2, 3, 4, and 5+ sport activities in adolescence with odds ratios: 1.52 (P=.11), 1.86 (P=.02), 1.29 (P=.39), and 3.12 (P=5.4e‐05), respectively. Within‐pair analyses, limited by the small sample of twins discordant for both adolescent activities and adult outcomes, did not replicate the association. A greater diversity of leisure‐time sport activities in adolescence predicts higher levels of LTPA in adulthood in females, but the causal nature of this association remains unresolved.
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