Near-infrared to visible and ultraviolet upconversion in TiO2 thin films modified with Er and Yb.

Upconversion as a modification strategy to enhance the utilization of sunlight in titanium dioxide photoanodes with an internal upconverter was investigated. TiO2 thin films containing an Er activator and Yb sensitizer were deposited in the magnetron sputtering process on conducting glass, amorphous silica, and silicon. Scanning electron microscopy, energy dispersive spectroscopy, grazing incidence X-ray diffraction, and X-ray absorption spectroscopy allowed assessment of the thin film composition, structure, and microstructure. Optical and photoluminescence properties were measured by means of spectrophotometry and spectrofluorometry. Changing the content of Er3+ (1, 2, 10 at%) and Yb3+ (1, 10 at%) ions allowed us to achieve thin film upconverters with a crystallized and amorphous host. Upon 980 nm laser excitation Er3+ exhibits upconversion with the main emission in green (2H11/2 → 4I15/2, λ em ≈ 525 nm) and weak emission in red (4F9/2 → 4I15/2, λ em ≈ 660 nm). For a thin film with a higher ytterbium content (10 at%) a significant increase in red emission and upconversion from NIR to UV was observed. The average decay times of green emission for TiO2:Er and TiO2:Er,Yb thin films were calculated based on time-resolved emission measurements.

Scavenger-Supported Photocatalytic Evidence of an Extended Type I Electronic Structure of the TiO2@Fe2O3 Interface.

Heterostructures of TiO2@Fe2O3 with a specific electronic structure and morphology enable us to control the interfacial charge transport necessary for their efficient photocatalytic performance. In spite of the extensive research, there still remains a profound ambiguity as far as the band alignment at the interface of TiO2@Fe2O3 is concerned. In this work, the extended type I heterojunction between anatase TiO2 nanocrystals and α-Fe2O3 hematite nanograins is proposed. Experimental evidence supporting this conclusion is based on direct measurements such as optical spectroscopy, X-ray photoemission spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), and the results of indirect studies of photocatalytic decomposition of rhodamine B (RhB) with selected scavengers of various active species of OH•, h•, e-, and •O2-. The presence of small 6-8 nm Fe2O3 crystallites at the surface of TiO2 has been confirmed in HRTEM images. Irregular 15-50 nm needle-like hematite grains could be observed in scanning electron micrographs. Substitutional incorporation of Fe3+ ions into the TiO2 crystal lattice is predicted by a 0.16% decrease in lattice parameter a and a 0.08% change of c, as well as by a shift of the Raman Eg(1) peak from 143 cm-1 in pure TiO2 to 149 cm-1 in Fe2O3-modified TiO2. Analysis of O 1s XPS spectra corroborates this conclusion, indicating the formation of oxygen vacancies at the surface of titanium(IV) oxide. The presence of the Fe3+ impurity level in the forbidden band gap of TiO2 is revealed by the 2.80 eV optical transition. The size effect is responsible for the absorption feature appearing at 2.48 eV. Increased photocatalytic activity within the visible range suggests that the electron transfer involves high energy levels of Fe2O3. Well-programed experiments with scavengers allow us to eliminate the less probable mechanisms of RhB photodecomposition and propose a band diagram of the TiO2@Fe2O3 heterojunction.

The Impact of Short-Term Shark Liver Oil Supplementation on the Fatty Acid Composition of Erythrocyte Membranes.

Fatty acid (FA) balance is strictly related to human health. The composition of fatty acids in lipid membranes seems to be influenced by diet. Shark liver oil (SLO) supplementation has been widely used recently in the prevention and treatment of human diseases. We analyzed the impact of short-term SLO supplementation on certain biochemical parameters and erythrocyte FA composition in a group of young healthy women. Our results showed that 6 weeks of SLO supplementation led to a significant decrease in C-reactive protein levels in sera and intracellular cholesterol levels in peripheral blood mononuclear cells. SLO supplementation caused a significant increase in the content of the polyunsaturated omega-3 FAs: docosahexaenoic acid, docosapentaenoic acid and α-linolenic acid. In the group of omega-6 FAs, we observed a significant elevation of arachidonic and dihomo-gamma-linoleic acid content. Due to these alterations, the omega-3 index increased significantly from 3.6% (before) to 4.2% (after supplementation). We also observed the impact of SLO supplementation on the membrane fluidity index. The ratio between saturated and unsaturated FAs decreased significantly from 13.1 to 9.9. In conclusion, our results show that even short-term SLO supplementation can improve human erythrocyte fatty acid composition and other parameters that may have health-promoting consequences.

Optically Active TiO2:Er Thin Films Deposited by Magnetron Sputtering.

Titanium dioxide photoanodes for hydrogen generation suffer from a profound mismatch between the optical absorption of TiO2 and the solar spectrum. To solve the problem of low solar-to-chemical efficiency, optically active materials are proposed. In this work, TiO2 thin films containing erbium were deposited by radio frequency RF magnetron sputtering under ultrahigh vacuum conditions UHV. Morphology, structural, optical and electronic properties were studied. TiO2:Er thin films are homogenous, with uniform distribution of Er ions and high transparency over the visible VIS range of the light spectrum. However, a profound 0.4 eV blue shift of the fundamental absorption edge with respect to undoped TiO2 was observed, which can be attributed either to the size effect due to amorphization of TiO2 host or to the onset of precipitation of Er2Ti2O7 nanocrystals. Near-infrared NIR to VIS up-conversion is demonstrated upon excitation at 980 nm, while strong green photoluminescence at 525 and 550 nm occurs upon photon absorption at 488 nm.

The value of magnetic resonance enterography in diagnostic difficulties associated with Crohn's disease.

PURPOSE: The diagnosis of Crohn's disease (CD), one of the inflammatory bowel diseases (IBD), along with ulcerative colitis (UC), is often challenging due to the limitations of small intestine visualisation. Magnetic resonance enterography (MRE) enables imaging of intraluminal and extraintestinal complications without ionizing radiation. The objective of this study is to select CD-related MRE features and determine the feasibility of this technique to indicate a group of patients that should be subjected to more invasive diagnostic procedures. MATERIAL AND METHODS: A total of 131 patients (mean age 25) underwent MRE, 60 of whom had been previously diagnosed with CD and 17 with UC. Additionally, 26 patients with suspected IBD and 28 with other or unknown pathologies were included in the study. Radiological reports of MRE examinations, effectuated using a 1.5-T field strength, were retrospectively analysed regarding radiological features of IBD, such as the following: bowel wall thickening, enhancement, comb sign, stricture, enlarged mesenteric nodes, inflammatory infiltration, and abnormal diffusion restriction in diffusion-weighted imaging. The statistical model was based on machine learning of the Kohonen map, together with univariate and multivariate analysis. RESULTS: The selected neuron (Neuron 3) incorporated 23 cases of CD, 9 of suspected IBD, 2 patients with UC, and 4 with other pathologies. The statistical analysis identified bowel wall thickening, intestinal stricture, and lymphadenopathy as the 3 MRE findings most associated with Neuron 3 (AUC = 0.919, p = 0.031). CONCLUSIONS: Bowel wall thickening, stricture, and enlarged mesenteric lymph nodes in MRE are independent predictive factors for CD diagnosis; thus, patients presenting these features should undergo further examinations. MRE constitutes a powerful imaging modality in cases of suspected IBD.

SnO2/TiO2 Thin Film n-n Heterostructures of Improved Sensitivity to NO2.

Thin-film n-n nanoheterostructures of SnO2/TiO2, highly sensitive to NO2, were obtained in a two-step process: (i) magnetron sputtering, MS followed by (ii) Langmuir-Blodgett, L-B, technique. Thick (200 nm) SnO2 base layers were deposited by MS and subsequently overcoated with a thin and discontinuous TiO2 film by means of L-B. Rutile nanopowder spread over the ethanol/chloroform/water formed a suspension, which was used as a source in L-B method. The morphology, crystallographic and electronic properties of the prepared sensors were studied by scanning electron microscopy, SEM, X-ray diffraction, XRD in glancing incidence geometry, GID, X-ray photoemission spectroscopy, XPS, and uv-vis-nir spectrophotometry, respectively. It was found that amorphous SnO2 films responded to relatively low concentrations of NO2 of about 200 ppb. A change of more than two orders of magnitude in the electrical resistivity upon exposure to NO2 was further enhanced in SnO2/TiO2 n-n nanoheterostructures. The best sensor responses RNO2/R0 were obtained at the lowest operating temperatures of about 120 °C, which is typical for nanomaterials. Response (recovery) times to 400 ppb NO2 were determined as a function of the operating temperature and indicated a significant decrease from 62 (42) s at 123 °C to 12 (19) s at 385 °C A much smaller sensitivity to H2 was observed, which might be advantageous for selective detection of nitrogen oxides. The influence of humidity on the NO2 response was demonstrated to be significantly below 150 °C and systematically decreased upon increase in the operating temperature up to 400 °C.

Up-to-date overview of imaging techniques in the diagnosis and management of inflammatory bowel diseases.

Radiological examination occupies a significant role, complementary to endoscopic studies, in the diagnostic process of inflammatory bowel disease (IBD). Both ulcerative colitis and Crohn's disease, due to multiple remissions and relapses, require repetitive examinations to evaluate the disease extent, severity, and response to pharmacological treatment. Whereas the use of barium contrast studies is progressively reduced, plain radiography confirms its utility as a first-line imaging tool for acute abdomen. Computed tomography remains an easily accessible and effective method to demonstrate disease activity and extraintestinal manifestations. However, the related radiation exposure reduces its applicability to urgent situations. Ultrasound and magnetic resonance, with the great advantage of avoiding ionising radiation, are highly recommended to present the complications of IBD. Use of oral and intravenous contrast in computed tomography enterography and magnetic resonance enterography demonstrates IBD involvement in the small intestine wall, which is difficult to assess in other radiological and endoscopic examinations.

Ultrasound elastography in the evaluation of peripheral neuropathies: a systematic review of the literature.

Peripheral neuropathy is associated with an increase in intraneural pressure, and hence ultrasound elastography seems to be an ideal method to detect early stages of this condition based on changes in the affected nerve stiffness. The aim of this systematic review was to analyse the applicability of strain elastography (SE) and shear wave elastography (SWE) in the evaluation of peripheral nerves in patients with neuropathy of various aetiologies. Published evidence shows clearly that ultrasound elastography can accurately diagnose many types of peripheral neuropathies (carpal tunnel syndrome and other entrapment neuropathies, diabetic peripheral neuropathy and peripheral neuropathy associated with other systemic diseases), sometimes at the stages at which the condition is still asymptomatic. However, it is still unclear whether elastographic changes within the nerves precede functional anomalies detectable on nerve conduction studies. Also, relatively little is known about the relationship between the stiffness of peripheral nerves and the severity of peripheral neuropathy and its underlying condition. Based on the reproducibility data, SWE seems to be superior to SE. Nevertheless, the sources of heterogeneity in the peripheral nerve stiffness in healthy persons need to be identified, and the sets of reference values for specific peripheral nerves need to be determined. Finally, the potential confounding effect of hardening artefacts, such as bones, on the stiffness of peripheral nerves needs to be verified. After addressing all these issues, elastographic evaluation of peripheral nerve stiffness might become a reliable, easily accessible, and convenient diagnostic test performed routinely in patients with various peripheral neuropathies.

Metabolic syndrome in overweight or obese children and adolescents based on own material Abstract Key words.

OBJECTIVE: Aim: To assess the prevalence of metabolic syndrome (MS) components in overweight or obese children and adolescents, as well as analyze the risk factors of its occurrence. PATIENTS AND METHODS: Material and methods: The study was conducted in a group of 70 children and adolescents aged 5-18 hospitalized in the Department of Gastroenterology, Allergology and Pediatrics, Polish Mother's Memorial Hospital - Research Institute in Lodz (Poland) based on the results of medical histories, physical examination, biochemical investigation, and calculation of the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index. RESULTS: Results: MS was diagnosed in 14 children (20%). The most common abnormalities besides obesity included: decreased High Density Lipoprotein Cholesterol (HDL-C) levels (n=13, 92.9%), increased triglycerides (TG) concentrations (n=10, 71.4%) and arterial hypertension (n=10, 71,4%). Among all the children, insulin resistance was diagnosed in 29 subjects (41.4%). The results of univariate logistic regression showed that the occurrence of lipid disorders, obesity, hypertension and diabetes in their parents, as well as the duration of pregnancy, birth weight, or breastfeeding were not associated with the risk of MS development in the subjects (p>0.05). However, in the study group, 92.9% of subjects had one or more particular risk factor for MS development. CONCLUSION: Conclusions: Besides visceral obesity, lipid disorders were the most frequently observed components of MS in the subjects analyzed, which may have prognostic significance. The occurrence of one or more MS risk factors in almost all of the children studied indicates the increased risk of cardiovascular diseases in the studied group in the future.

Nanocrystalline TiO2/SnO2 heterostructures for gas sensing.

The aim of this research is to study the role of nanocrystalline TiO2/SnO2 n-n heterojunctions for hydrogen sensing. Nanopowders of pure SnO2, 90 mol % SnO2/10 mol % TiO2, 10 mol % SnO2/90 mol % TiO2 and pure TiO2 have been obtained using flame spray synthesis (FSS). The samples have been characterized by BET, XRD, SEM, HR-TEM, Mössbauer effect and impedance spectroscopy. Gas-sensing experiments have been performed for H2 concentrations of 1-3000 ppm at 200-400 °C. The nanomaterials are well-crystallized, anatase TiO2, rutile TiO2 and cassiterite SnO2 polymorphic forms are present depending on the chemical composition of the powders. The crystallite sizes from XRD peak analysis are within the range of 3-27 nm. Tin exhibits only the oxidation state 4+. The H2 detection threshold for the studied TiO2/SnO2 heterostructures is lower than 1 ppm especially in the case of SnO2-rich samples. The recovery time of SnO2-based heterostructures, despite their large responses over the whole measuring range, is much longer than that of TiO2-rich samples at higher H2 flows. TiO2/SnO2 heterostructures can be intentionally modified for the improved H2 detection within both the small (1-50 ppm) and the large (50-3000 ppm) concentration range. The temperature Tmax at which the semiconducting behavior begins to prevail upon water desorption/oxygen adsorption depends on the TiO2/SnO2 composition. The electrical resistance of sensing materials exhibits a power-law dependence on the H2 partial pressure. This allows us to draw a conclusion about the first step in the gas sensing mechanism related to the adsorption of oxygen ions at the surface of nanomaterials.

Solution and solid state 13C NMR and X-ray studies of genistein complexes with amines. Potential biological function of the C-7, C-5, and C4'-OH groups.

Parent genistein and its new amine complexes with morpholine and piperazine were studied comparatively in the solid and liquid states by X-ray crystallography and 13C and 15N NMR spectroscopy. Biochanine A and its complexes were used as reference. Secondary deuterium isotope effects on 13C chemical shifts in solution were studied in parent isoflavones and their morpholine and piperazine complexes to aid in evaluation of the electronic distribution in both systems. In addition, to quantify the extent of proton transfer as well as to establish strong hydrogen bonding of the 7-OH group in a morpholine complex, proton transfer from the 7-OH group to the piperazine nitrogen atom was also confirmed by 13C NMR in the solid state and by X-ray studies. The effect of 7-OH deprotonation yields a high frequency shift of 7-8 ppm on the C-7 carbon atom of the piperazine complex whereas it is as large as 12 ppm in the morpholine complex in the solid. The former trend is confirmed from solution state concentration studies which also show that the isoflavones have a strong tendency to form complexes with bases. Depending on the pKa difference between the isoflavones and the base this leads either to proton transfer and ion-pair formation or, in the case of a larger pKa difference, to a hydrogen bonded ion pair. The concentration studies show formation of a 1:1 genistein-piperazine complex in DMSO. Addition of water leads to formation of solvent separated ions. The C-5 OH group is involved in strong intramolecular hydrogen bonding leading to a pseudo aromatic ring extending the aromatic part of the drug pharmacophore. The analysis also suggests the way that both the C-7 and C-4' hydroxyl group of genistein may participate in stabilising the ternary inhibitor complexes of tyrosine-specific kinases or DNA topoisomerase II.