Strategy for Increased Stability in Africa

During the 1960s, independence swept Africa like fire on the savannah. As country after country threw off the yoke of imperialism and colonialism, nationalism and self-determination rose to replace them. Many intellectuals, economists, and philosophers, in both Africa and the more developed countries, firmly believed that the continent faced a brilliant future

Durability of biodegradable polymers for the conservation of cultural heritage

The use of polymers for conservation of cultural heritage is related to the possibility to slow down or stop natural deterioration which, in many cases, corresponds to stopping the entrance of liquid water and to favor spontaneous water vapor removal. Unfortunately, hydrophobicity is generally favored by surface roughness and thus competitive with transparency. It is therefore important to find an optimal balance hydrophobicity, transparency and durability (especially to photooxidation). However, polymers typically used for applications in this field come from non-renewable resources and are not biodegradable. In this work, the mechanical, structural, and optical properties of PLA, PBAT, and a PBAT/PLA blends, as well as surface properties and water vapor permeability, were investigated before and after exposure to UV irradiation, in order to evaluate their durability and suitability for conservation of cultural heritage

One-step electrodeposition of superhydrophobic coating on 316L stainless steel

Superhydrophobic coatings were fabricated through a one-step electrochemical process onto the surface of 316L stainless steel samples. The presence of hierarchical structures at micro/ nanoscale and manganese stearate into the coatings gave superhydrophobicity to the coating, with contact angle of ~160◦, and self-cleaning ability. Corrosion resistance of 316L samples was also assessed also after the electrodeposition process through Electrochemical Impedance Spectra recorded in an aqueous solution mimicking seawater condition

Improved Cu2O/AZO Heterojunction by Inserting a Thin ZnO Interlayer Grown by Pulsed Laser Deposition

Cu2O/ZnO:Al (AZO) and Cu2O/ZnO/AZO heterojunctions have been deposited on glass substrates by a unique three-step pulsed laser deposition process. The structural, optical, and electrical properties of the oxide films were investigated before their implementation in the final device. X-ray diffraction analysis indicated that the materials were highly crystallized along the c-axis. All films were highly transparent in the visible region with enhanced electrical properties. Atomic force and scanning electron microscopies showed that the insertion of a ZnO layer between the Cu2O and AZO films in the heterojunction enhanced the average grain size and surface roughness. The heterojunctions exhibited remarkable diode behavior and good rectifying character with low leakage current under reverse bias. The presence of the ZnO interlayer film significantly reduced the parasitic and leakage currents across the barrier, improved the quality of the heterostructure, made the energy band between AZO and Cu2O layers smoother, and eliminated the possibility of interface recombination, leading to much longer electron lifetime

Unenhanced whole-body MRI versus PET-CT for the detection of prostate cancer metastases after primary treatment

The aim of this study was to evaluate the accuracy of unenhanced whole-body MRI, including whole-body Diffusion Weighted Imaging (DWI), used as a diagnostic modality to detect  pathologic lymph nodes and skeletal metastases in patients with prostate cancer (PCa) undergoing restaging after primary treatment

Rapid One-Step Fabrication of Graphene Oxide-Decorated Polycaprolactone Three-Dimensional Templates for Water Treatment

Coating of flexible substrates is crucial to prepare versatile, multifunctional materials. However, exploration of effective fabrication approaches is still a challenging issue, because the pathways generally proposed require time-consuming, multistep protocols. Here, we developed a one-pot process for decorating either pearl necklace-like or fibrous fluffy-like structures of polycaprolactone (PCL) with graphene oxide (GO) skin. PCL solutions were dry jet-wet electrosprayed or electrospun into a stirred liquid collector constituted by ethanol-containing GO nanoparticles. The stirred liquid collector enables the formation of 3D-structures, whose microarchitecture can be designed by controlling the rheological behavior of PCL solutions. Two molecular weights of PCL were used (45 or 80 kDa) with ensuing different viscosity, which determines the prevalent formation of beads or fibers. The presence of GO in the coagulation bath allows the polymeric structures to be rapidly wrapped by those nanoparticles. Graphenic coating endows these materials with the intriguing peculiarities of GO: PCL/GO nanocomposites displayed increments of elastic modulus ranging from 1250% (beads) to 3300% (fibers) with respect to the neat matrices and a change from hydrophobic to amphiphilic character. A potential application of such devices in water treatment was assessed in phenol removal. The results pointed out that PCL/GO scaffolds retain the same sorption capacity of GO nanoparticles, while bringing several advantages in terms of handling, robustness, and recyclability. The ease of control of the process, as well as its fastness and cost-effectiveness could open a wide range of scenarios, including sensors, energy, catalysis, biomedicine

Halloysite nanotubes-based nanocomposites for the hydrophobization of hydraulic mortar

Abstract: The treatment of stone surfaces for their protection from ageing caused by natural and anthropogenic effects is an open issue in materials development for Cultural Heritage. We thought interesting to verify the suitability of a modified cellulose biofilm filled with halloysite nanotubes as wax compatibilizers to design a protecting layer. A hydraulic mortar was selected as a stone prototype. To improve the physico-chemical properties of the covering layer, wax microparticles have been incorporated to control transport, consolidation and wettability features. In particular, different application protocols have been studied, namely brushing and spraying, to assess whether the proposed procedures can be scaled up. Colorimetric analysis has been carried out to evidence the applicability in terms of color alteration after the treatment. Water adhesion was investigated by measuring the contact angle values as a function of time to obtain information on spreading and adsorption phenomena. These physico-chemical properties have been correlated to the microstructure evidenced by both electron and optical microscopies

ACOUSTIC ANALYSIS OF SWALLOWING SOUNDS: A NEW TECHNIQUE FOR ASSESSING DYSPHAGIA

Objective: To perform acoustic analysis of swallowing sounds, using a microphone and a notebook computer system, in healthy subjects and patients with dysphagia affected by neurological diseases, testing the positive/negative predictive value of a pathological pattern of swallowing sounds for penetration/aspiration. Design: Diagnostic test study, prospective, not blinded, with the penetration/aspiration evaluated by fibreoptic endo scopy of swallowing as criterion standard. Subjects: Data from a previously recorded database of normal swallowing sounds for 60 healthy subjects according to gender, age, and bolus consistency was compared with those of 15 patients with dysphagia from a university hospital referral centre who were affected by various neurological diseases. Methods: Mean duration of the swallowing sounds and postswallowing apnoea were recorded. Penetration/aspiration was verified by fibreoptic endoscopy of swallowing in all patients with dysphagia. Results: The mean duration of swallowing sounds for a liquid bolus of 10 ml water was significantly different between patients with dysphagia and healthy patients. We also described patterns of swallowing sounds and tested the negative/positive predictive values of post-swallowing apnoea for penetration/aspiration verified by fibreoptic endoscopy of swallowing (sensitivity 0.67 (95% confidence interval 0.24–0.94); specificity 1.00 (95% confidence interval 0.56–1.00)). Conclusion: The proposed technique for recording and measuring swallowing sounds could be incorporated into the bedside evaluation, but it should not replace the use of more diagnostic and valuable measures

Egg Cannibalism in a Gull Colony Increases with Sea Surface Temperature

Cannibalism occurs regularly across a broad range of taxa with a variety of ecological and evolutionary consequences. Rises in sea surface temperature (SST) have been linked to increased cannibalism in some species, including polar bears (Ursus maritimus), Peruvian anchovy (Engraulis ringens), and Peruvian hake (Merluccius gayi peruanus), and might be expected in birds that depend on marine food webs for sustenance. Increased SSTs are associated with lowered ocean thermoclines and weakened upwellings. These changes, in turn, lead to decreased productivity in surface water and movement of surviving forage fish to deeper water, thereby food-stressing surface feeders such as gulls, diminishing energy intake and lengthening foraging bouts. While controlling for a suite of other environmental factors, we tested whether egg cannibalism and hatching success were independent of rises in local SST at a colony of Glaucous-winged Gulls (Larus glaucescens) and Glaucous-winged3Western Gull (L. glaucescens3occidentalis) hybrids during 2006–2011 on Protection Island, Washington, USA. Cannibalism increased and hatching success decreased with rises in SST. It is unclear if rises in SST impact overall population trends. Gulls are multiyear breeders; if they experience reproductive failure during one or several El Ni ˜ no-Southern Oscillation–related events, they typically have other opportunities to breed. With rising SSTs associated with climate change, however, increasing levels of cannibalism could lead to declining populations in the absence of compensatory adaptive modifications or range shifts

Coping Behaviour as an Adaptation to Stress: Post-Disturbance Preening in Colonial Seabirds

In humans, coping behaviour is an action taken to soothe oneself during or after a stressful or threatening situation. Some human behaviours with physiological functions also serve as coping behaviours, for example, comfort sucking in infants and comfort eating in adults. In birds, the behaviour of preening, which has important physiological functions, has been postulated to soothe individuals after stressful situations. We combine two existing modelling approaches – logistic regression and Darwinian dynamics – to explore theoretically how a behaviour with crucial physiological function might evolve into a coping behaviour. We apply the method to preening in colonial seabirds to investigate whether and how preening might be co-opted as a coping behaviour in the presence of predators. We conduct an in-depth study of the environmental correlates of preening in a large gull colony in Washington, USA, and we perform an independent field test for comfort preening by computing the change in frequency of preening in gulls that were alerted to a predator, but did not flee