We present a new method, fast and low demanding in terms of CPU performances, which is able to extract latent chemical information from ToF-SIMS big data sets, such as those arising from chemical ...imaging, by working on the unbinned raw data files. The method is able to evaluate the similarity/dissimilarity of very low intensity spectra, such as those arising from a single pixel, in terms of symmetry and asymmetry relationships of the count distribution in the Fourier transform domain. The tests performed so far on model samples show that the method supplies results that, without sacrificing mass or spatial resolution, are equivalent, at least, to those achievable by an experienced ToF-SIMS user by applying PCA techniques.
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IJS, KILJ, NUK, PNG, UL, UM
The effects of night shift work on health status have been widely studied. Night workers seem to smoke more, eat badly and show a low propensity to physical activity. Night work can be associated ...with an increase in cardiovascular and gastrointestinal disorders, alterations in immune response, diabetes, aging, hormonal imbalance, and premature death; alteration of circadian rhythm is also regarded as a risk factor for breast cancer and neuropsychiatric disorders. Moreover, several studies have highlighted the effects of sleep deprivation on clinical performance, quality of care and personal safety of healthcare personnel. No studies have investigated the effects of night work on Italian resident physicians and compared its effect across specialties. This study aims to assess the prevalence of sleep disorders, possible cognitive impairment and mood states, in relation to night shift work among resident physicians.
80 resident physicians, attending the postgraduate training into an Hospital located in the South of Italy, were divided into 4 areas (medical, surgical, services and anaesthesia). They were recruited from July 2017 to June 2018 and participated to a survey consisting of 4 questionnaires to investigate the presence of sleep deprivation and sleep quality (Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index), their cognitive status (Mini Mental State examination) and mood profiles (Profile of Mood States, POMS). Analysis of variance was used for comparison of questionnaires scores across specialties.
Authors reported no sleep deprivation, no sleep disorders and their outcomes, no changes in intellectual efficiency and no cognitive impairment in this population, neither in the areas performing night shifts nor in those involving only day shifts. Mood states measured by POMS showed a borderline level of Anger-Hostility (A) value among the residents of the medical area and services, and an increase slightly beyond the physiological levels of the T-score 50 of Fatigue-Inertia (F) always in the same groups. An increase in the Vigour-Activity (V) value beyond T-score 50 levels was also observed among residents of all the areas considered.
Emotional involvement could be attributed to the gap between high professional demand and lack of experience and knowledge among trainees. Tutors should help their students in order to identify earlier changes in the mood. Improvement in the organization of the trainee's activity could reduce the emotional overload.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of this study was to determine the effectiveness of a Super absorbent polymer (SAP) containing copper (SAP-Cu) in controlling mal secco disease (MSD) of lemon caused by the fungus
Plenodomus ...tracheiphilus
. Super absorbent polymer containing copper was characterized by atomic absorption spectrometry (AAS) and UV-VIS spectroscopy.
In vitro
tests were performed to determine the inhibitory effects of SAP-Cu against the pathogen on both potato-dextrose-agar medium and naturally infected lemon cuttings. Super absorbent polymer was able to absorb up to about 200 and 30 times its weight of ionized water and copper (II) sulfate solution (Cu
2+
ions at the concentration 236 mM), respectively. The distribution of copper released on twigs after 24 h of contact with SAP-Cu was determined by secondary ion mass spectrometry with time-of-flight analyzer (ToF-SIMS). Super absorbent polymer containing copper significantly inhibited the viability of
P. tracheiphilus
in lemon twigs. Overall, the results of this study showed that the SAP could be a suitable carrier of antifungal compounds.
A strategy for creating a general-purposes surface functionalization platform is reported, based on direct attachment of phosphate groups onto hydroxylated surfaces and subsequent formation of a ...terpyridine-based monolayer. Such a platform is suitable for the construction, onto technologically relevant oxide surfaces, of single- and multilayer structures of interest in technological applications. In particular, the paper describes the successful attachment of 4-(2,2′:6′,2′′-terpyridine-4-yl)benzenephosphonic acid (1, PPTP) onto a SiO2 surface previously functionalized by means of Zr-phosphate groups. Two alternative anchoring strategies of the PPTP were explored: (i) a direct one-step way, implying no protection of terpyridinic functionality, and (ii) a three-step way, implying protection and successive deprotection of this group. It was found that, in the first case, the PPTP ligand anchoring to the Zr-containing phosphate layer takes place by means of terpyridinic group. At variance of this, in the second case, due to the protection of the terpyridinic functionality, the anchoring process takes place through the phosphonic group, making the terpyridinic moiety available for further reactions, i.e., multilayer constructs. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF−SIMS) were used to study the functionalized surfaces, providing information on coverage, chemical structure, and stoichiometry of the various functionalized layers and, among the others, clear evidence of the PPTP linkage and orientation.
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A new automated procedure able to extract latent chemical information from ToF-SIMS big data sets is presented. A classifier based on a probabilistic neural network able to provide a correct ...classification of spectra acquired from four different polymers is designed and trained. The procedure is fast and low-demanding in terms of CPU performances, and it is also able to evaluate the similarity/dissimilarity in the Fourier transform domain of very low intensity single pixel spectra without any effort of the analyst.
•New automated procedure able to extract latent chemical information from ToF-SIMS big data sets.•Classifier based on a probabilistic neural network able to provide a correct classification of spectra acquired from four different polymers.•Fast procedure which is able to evaluate a very low intensity single pixel spectra without any effort of the analyst.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The limitations and difficulties that nerve autografts create in normal nerve function recovery after injury is driving research towards using smart materials for next generation nerve conduits (NCs) ...setup. Here, the new polymer partially oxidized polyvinyl alcohol (OxPVA) was assayed to verify its future potential as a bioactivated platform for advanced/effective NCs. OxPVA-patterned scaffolds (obtained by a 3D-printed mold) with/without biochemical cues (peptide IKVAV covalently bound (OxPVA-IKVAV) or self-assembling peptide EAK (sequence: AEAEAKAKAEAEAKAK), mechanically incorporated (OxPVA+EAK) versus non-bioactivated scaffold (peptide-free OxPVA (PF-OxPVA) supports, OxPVA without IKVAV and OxPVA without EAK control scaffolds) were compared for their biological effect on neuronal SH-SY5Y cells. After cell seeding, adhesion/proliferation, mediated by (a) precise control over scaffolds surface ultrastructure; (b) functionalization efficacy guaranteed by bioactive cues (IKVAV/EAK), was investigated by MTT assay at 3, 7, 14 and 21 days. As shown by the results, the patterned groove alone stimulates colonization by cells; however, differences were observed when comparing the scaffold types over time. In the long period (21 days), patterned OxPVA+EAK scaffolds distinguished in bioactivity, assuring a significantly higher total cell amount than the other groups. Experimental evidence suggests patterned OxPVA-EAK potential for NCs device fabrication.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Protein adsorption plays a key role in the biological response to implants. We report how nanoscale topography, chemistry, crystallinity, and molecular chain anisotropy of ultrahigh molecular weight ...polyethylene (UHMWPE) surfaces affect the protein assembly and induce lateral orientational order. We applied ultraflat, melt drawn UHMWPE films to show that highly oriented nanocrystalline lamellae influence the conformation and aggregation into network structures of human plasma fibrinogen by atomic force microscopy with unprecedented clarity and molecular resolution. We observed a transition from random protein orientation at low concentrations to an assembly guided by the UHMWPE surface nanotopography at a close to full surface coverage on hydrophobic melt drawn UHMWPE. This assembly differs from the arrangement at a hydrophobic, on the nanoscale smooth UHMWPE reference. On plasma-modified, hydrophilic melt drawn UHMWPE surfaces that retained their original nanotopography, the influence of the nanoscale surface pattern on the protein adsorption is lost. A model based on protein−surface and protein−protein interactions is proposed. We suggest these nanostructured polymer films to be versatile model surfaces to provide unique information on protein interactions with nanoscale building blocks of implants, such as nanocrystalline UHMWPE lamellae. The current study contributes to the understanding of molecular processes at polymer biointerfaces and may support their future design and molecular scale tailoring.
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IJS, KILJ, NUK, PNG, UL, UM
The pioneering study of Shimizu
et al.
(
J. Anal. At. Spectrom.
, 2004,
19
, 692) on the examination of adsorbed organic molecules on a copper substrate by radio frequency glow discharge optical ...emission spectrometry (rf-GDOES) displayed the potential of GDOES for determination of the orientations of molecular monolayers. Here, the study has been extended to the examination of thiourea adsorbed on silver, gold and copper surfaces and metal-centred molecular wires (MCMWs) of 4-6 nm length, with cobalt atoms in the middle of the chain adsorbed on a gold surface. According to established data, these molecules are adsorbed onto a metal surface through a sulphur atom. Depth profiling of thiourea adsorbed on the copper surface confirmed the results of Shimizu
et al.
, with a nitrogen peak followed by a sulphur peak in the depth profile revealed with sputtering time. However, in the case of silver and gold substrates, the positions of the sulphur and nitrogen peaks in the depth profiles were not as predicted from the orientation of the thiourea molecule,
i.e.
the nitrogen peak followed the sulphur peak with sputtering time or the peaks overlapped. In the depth profiles of the adsorbed MCMWs, the sulphur peak appeared prior to the cobalt peak with sputtering time. Further, the time required for sputtering of thiourea and the wires are comparable, whereas the lengths of thiourea and the wire molecules differ by more than one order of magnitude. Thus, in this case, no correlation between the orientation of the molecules and the peak sequence in the depth profiles has been observed.
Molecular monolayers adsorbed on metal surfaces were analysed by GDOES revealing no correlation between the orientation of the molecules and the peak sequence in the depth profiles.
We report on the use of the self-organization process of sputtered gold nanoparticles on a self-assembled block copolymer film deposited by horizontal precipitation Langmuir-Blodgett (HP-LB) method. ...The morphology and the phase-separation of a film of poly-
n
-butylacrylate-
block
-polyacrylic acid (P
n
BuA-
b
-PAA) were studied at the nanometric scale by using atomic force microscopy (AFM) and Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The templating capability of the P
n
BuA-
b
-PAA phase-separated film was studied by sputtering gold nanoparticles (NPs), forming a film of nanometric thickness. The effect of the polymer chain mobility onto the organization of gold nanoparticle layer was assessed by heating the obtained hybrid P
n
BuA-
b
-PAA/Au NPs bilayer at
T
>
T
g
. The nanoparticles' distribution onto the different copolymer domains was found strongly affected by the annealing treatment, showing a peculiar memory effect, which modifies the AFM phase response of the Au NPs layer onto the polar domains, without affecting their surfacial composition. The effect is discussed in terms of the peculiar morphological features induced by enhanced mobility of polymer chains on the Au NPs layer.
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