Ammonia gas sensors based on undoped and Ca-doped ZnO nanoparticles.

Due to its large use in different industrial sectors, high toxicity, and corrosion, the demand for sensing techniques towards ammonia gas has become urgent. In this study we report on the sensing performances of a conductometric sensor for NH3 gas based on Ca-doped ZnO nanoparticles with different calcium concentrations (0, 1, and 3 at%) synthesized using the sol-gel process under supercritical dry conditions of ethanol. All samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. Pure and Ca-doped ZnO are polycrystalline and well crystallized in the hexagonal wurtzite structure. TEM images revealed that pure ZnO is composed of spherical particles with dimensions in the nanometer range. Larger particles were observed after the incorporation of Ca ions. The average crystallite size, estimated by the Williamson-Hall method, was 43, 80, and 96 nm for pure, Ca-1 at% and Ca-3 at%, respectively. Furthermore, FTIR spectroscopy was used to prove the formation of ZnO and the incorporation of calcium ions in the Ca-doped ZnO samples. The gas sensing performances towards ammonia gas clearly ameliorated after the addition of Ca ions in the ZnO structure. The gas response to NH3, R0/Rg, of the 1% Ca-doped ZnO sensor reached a value of 33 for 4000 ppm of ammonia at T = 300 °C with good selectivity compared to other gases such as CO, CO2, and NO2. The response and recovery times were 5 s and 221 s, respectively. The reported good sensing performances indicate the potential application of Ca-doped ZnO as a sensor material for ammonia detection.

Snip conjunctivoplasty associated with methylene blue staining for treatment of postoperative conjunctival chemosis.

Conjunctival chemosis usually undergoes spontaneous resolution; sometimes, it requires treatment. We present the case of a 43 years-old female patient who developed bilateral conjunctival chemosis following upper and lower blepharoplasty. Two months after the operation, patient underwent bilateral snip conjunctivoplasty with methylene blue demarcation of the chemotic conjunctiva.

NdFeO3 as a new electrocatalytic material for the electrochemical monitoring of dopamine.

A new electrochemical sensor, based on NdFeO3 nanoparticles as electrocatalytic material, was proposed here for the detection of dopamine (DA). NdFeO3 nanoparticles were first synthesized by a simple thermal treatment method and subsequent annealing at high temperature (700 °C). The prepared electrocatalytic material has been characterized in detail by SEM-EDX, XRD, and Raman techniques. Characterization results display its sheet-like morphology, constituted by a porous network of very small orthorhombic NdFeO3 nanoparticles. NdFeO3 electrocatalytic material was then used to modify the working electrode of screen-printed carbon electrodes (SPCEs). Electrochemical tests demonstrated that NdFeO3- modified screen-printed carbon electrode (NdFeO3/SPCE) exhibited a remarkable enhancement of the dopamine electrooxidation, compared to the bare SPCE one. The analytical performance of the developed sensor has been evaluated for the detection of this analyte by means of the square-wave voltammetry (SWV) technique. The modified electrode showed two linear concentration ranges, from 0.5 to 100 µM and 150 to 400 µM, respectively, a limit of detection (LOD) of 0.27 µM (at S/N = 3), and good reproducibility, stability, and selectivity. Additionally, we also report an attempt made to propose the modified sensor for the simultaneous detection of dopamine and uric acid (UA). The procedure was also applied for the determination of dopamine in spiked real samples. So, this paper reports for the first time the use of a modified NdFeO3 screen-printed electrode for developing an electrochemical sensor for the quantification of important biomolecules. Graphical abstract.

α-MoO3 nanostructure on carbon cloth substrate for dopamine detection.

Orthorhombic molybdenum oxide (α-MoO3) nanostructures were deposited on the surface of carbon cloth (CC) as a flexible and high conductive scaffold by reactive RF magnetron sputtering technique. Structure and morphology of the as prepared molybdenum coated carbon cloth (MoO3CC) were thoroughly characterized with field emission scanning electron microscopy, x-ray diffraction, energy dispersive x-ray and Raman spectroscopy. Benefiting from high surface area and superior conductivity of CC as well as electrocatalytic activity of α-MoO3 nanostructures, an electrochemical sensor was fabricated. The electrochemical behavior of this new sensor toward determination of dopamine was studied in detail by cyclic voltammetry, amperometry (AM) and square wave voltammetry (SWV). Results reported here reveal that using SWV not only enhances the sensitivity of sensors to dopamine by more than 14 times compared to AM, but also offers higher linear dynamic range (1-700 µM compared to 5-550 µM). Limit of detection, for signal to noise ratio 3, was calculated to be 0.48 µM. Applicability of the proposed sensor for measurement of dopamine in real samples, like urine and pharmaceutical formulation, was also evaluated that concluded to satisfactory results.

High performance acetone sensor based on γ-Fe2O3/Al-ZnO nanocomposites.

Ternary nanocomposites made of γ-iron oxide and aluminum-doped zinc oxide (γ-Fe2O3/Al-ZnO NCs), with different metal oxides ratio (0%-100%) were prepared through a solvothermal sol-gel process. The synthesized materials were characterized by x-ray diffraction, UV-vis spectroscopy, photoluminescence (PL), scanning electron microscope and BET analysis. Characterization results demonstrated that the ternary γ-Fe2O3/Al-ZnO NCs are mainly constituted by γ-Fe2O3 and Al-ZnO individual phases, while structural and physical properties like surface area, pore size, optical band gap, PL and electrical conductivity were deeply affected by the composition of nanocomposite. The synthesized γ-Fe2O3/Al-ZnO NCs were employed to prepare conductometric gas sensors, then their sensing performances toward acetone were also investigated. Results revealed enhanced sensing performance of nanocomposites than both pure γ-Fe2O3 and Al-ZnO phases. In particular, the γ-Fe2O3(33%)/Al-ZnO based gas sensor showed the best sensing properties, like a high response of R air/R gas = 29, a short response time of 3 s, in addition to an improved selectivity toward acetone versus ethanol at an operating temperature of 200 °C. Overall, ternary γ-Fe2O3/Al-ZnO NCs appear to be promising for the development of conductometric acetone sensors.

Manganese Doped Hydroxyapatite Nanoparticles Based Enzyme-Less Electrochemical Sensor for Detecting Hydroquinone.

Manganese (Mn) doped hydroxyapatite (HA) nanoparticles were synthesized by a simple microwave irradiation method and characterized using XRD, SEM, micro-Raman, FTIR, XPS and vibrating sample magnetometer (VSM) methods. The as prepared 3 M% Mn doped HA (3 M% Mn-HA) nanoparticles modified glassy carbon electrode (GCE) showed an excellent electrocatalytic activity towards the oxidation of hydroquinone (HQ). The electrochemical studies demonstrated that the 3 M% Mn-HA nanoparticles modified GCE detects HQ linearly over a wide concentration range of 1.0×10-8 to 1.6×10-4 M with the lowest detection limit of 11 nM at neutral pH (7.0) in PBS. Furthermore, Mn-HA modified GCE exhibited an excellent stability, reproducibility and anti-interference ability against a number of potential electroactive species and metal ions and proved to be useful for the estimation of the HQ in tap water and industry waste water with satisfactory recovery.

A water-filled garment to protect astronauts during interplanetary missions tested on board the ISS.

As manned spaceflights beyond low Earth orbit are in the agenda of Space Agencies, the concerns related to space radiation exposure of the crew are still without conclusive solutions. The risk of long-term detrimental health effects needs to be kept below acceptable limits, and emergency countermeasures must be planned to avoid the short-term consequences of exposure to high particle fluxes during hardly predictable solar events. Space habitat shielding cannot be the ultimate solution: the increasing complexity of future missions will require astronauts to protect themselves in low-shielded areas, e.g. during emergency operations. Personal radiation shielding is promising, particularly if using available resources for multi-functional shielding devices. In this work we report on all steps from the conception, design, manufacturing, to the final test on board the International Space Station (ISS) of the first prototype of a water-filled garment for emergency radiation shielding against solar particle events. The garment has a good shielding potential and comfort level. On-board water is used for filling and then recycled without waste. The successful outcome of this experiment represents an important breakthrough in space radiation shielding, opening to the development of similarly conceived devices and their use in interplanetary missions as the one to Mars.

Green and fast determination of the alcoholic content of wines using thermal infrared enthalpimetry.

An innovative use of thermal infrared enthalpimetry (TIE) is proposed for the determination of alcoholic content of red and white wines. Notwithstanding the presence of ethanol in beverages, absolute ethanol was added directly to wines, and the temperature rise caused by the heat of dilution was monitored using an infrared camera. Analytical signals were obtained in only 10 s for four samples simultaneously, and a calibration curve was constructed with hydroalcoholic reference solutions. A linear calibration curve was obtained from 3.0 to 18.0% (v/v) ethanol (R2 = 0.9987). The results showed agreement ranging from 98.2 to 104.0% with 942.06 and 969.12 methods of AOAC. Organic compounds (e.g., sugar) did not interfere in the determinations. The proposed method provided fast results, with a throughput of 480 samples per hour and negligible energy consumption (0.001 kWh). In addition, the consumption of reagents was reduced when compared with conventional method fulfilling green analytical chemistry requirements.

Diagnosis of a neonatal ophthalmic discharge, Ophthalmia neonatorum, in the molecular age: investigation for a correct therapy.

An early double case of acute Ophthalmia neonatorum in 3-day-old twins is reported. Culture of eye swabs showed a wide bacterial polymorphism, in which common bacteria, such as Klebsiella pneumoniae, Streptococcus pneumoniae, Corynebacterium ulcerans and other Enterobacteriaceae, coexisted with atypical Mycoplasmataceae and Chlamydiaceae from resident cervical-vaginal maternal microbiota. The neonates were in an apparently healthy state, but showed red eyes with abundant greenish-yellow secretion, mild chemosis and lid edema. The maternal cervical-vaginal ecosystem resulted differently positive to the same common cultivable, atypical bacteria culturally and molecularly determined. This suggested a direct maternal-foetal transmission or a further foetal contamination before birth. An extended culture analysis for common bacteria to atypical ones was decisive to describe the involvement of Mycoplasmas (M. hominis and U. urealyticum) within the scenario of the Ophthalmia neonatorum in a Caucasian couple. The introduction of a routine PCR molecular analysis for Chlamydiaceae and N. gonorrhoeae allowed to establish which of these were present at birth, and contributed to determine the correct laboratory diagnosis and to define an adequate therapeutic protocol obtaining a complete resolution after one year for culture and atypical bacteria controls. This study suggests to improve the quality of laboratory diagnosis as unavoidable support to a correct clinical diagnosis and therapy, in a standardized modality both for swabbing and scraping, to check the new-born microbial programming starting in uterus, overtaking the cultural age to the molecular age, and to revise the WHO guidelines of SAFE Strategy for trachoma eye disease, transforming it into SAFES Strategy where the S letter is the acronym of Sexual ecosystem and behavioural valuation/education.

Tracking areal lithium densities from neutron activation - quantitative Li determination in self-organized TiO2 nanotube anode materials for Li-ion batteries.

Nanostructuring of electrode materials is a promising approach to enhance the performance of next-generation, high-energy density lithium (Li)-ion batteries. Various experimental and theoretical approaches allow for a detailed understanding of solid-state or surface-controlled reactions that occur in nanoscaled electrode materials. While most techniques which are suitable for nanomaterial investigations are restricted to analysis widths of the order of Å to some nm, they do not allow for characterization over the length scales of interest for electrode design, which is typically in the order of mm. In this work, three different self-organized anodic titania nanotube arrays, comprising as-grown amorphous titania nanotubes, carburized anatase titania nanotubes, and silicon coated carburized anatase titania nanotubes, have been synthesized and studied as model composite anodes for use in Li-ion batteries. Their 2D areal Li densities have been successfully reconstructed with a sub-millimeter spatial resolution over lateral electrode dimensions of 20 mm exploiting the 6Li(n,α)3H reaction, in spite of the extremely small areal Li densities (10-20 µg cm-2 Li) in the nanotubular active material. While the average areal Li densities recorded via triton analysis are found to be in good agreement with the electrochemically measured charges during lithiation, triton analysis revealed, for certain nanotube arrays, areas with a significantly higher Li content ('hot spots') compared to the average. In summary, the presented technique is shown to be extremely well suited for analysis of the lithiation behavior of nanostructured electrode materials with very low Li concentrations. Furthermore, identification of lithiation anomalies is easily possible, which allows for fundamental studies and thus for further advancement of nanostructured Li-ion battery electrodes.

Synthesis, characterization and electrochemical properties of 5-aza[5]helicene-CH2O-CO-MWCNTs nanocomposite.

In this study, we report the preparation of a novel nanocomposite, 5-aza[5]helicene-CH2O-CO-MWCNTs, obtained by grafting the 5-aza[5]helicene moiety on the surface of multi-walled carbon nanotubes (MWCNTs). Thermogravimetry (TGA), Fourier transform-infrared spectroscopy (FTIR), ultraviolet (UV), and photoluminescence (PL) measurements provided evidence that the organic moiety is covalently grafted to the MWCNTs. The 5-aza[5]helicene-CH2O-CO-MWCNTs nanocomposite was utilized to fabricate modified commercial screen-printed carbon electrodes. Its electrochemical behavior was studied in neutral buffer solution in the presence of ferricyanide and hydroquinone (HQ). Finally, the electrochemical sensing of epinephrine in the presence of ascorbic acid by using the linear sweep voltammetry (LSV) technique was investigated. Results have demonstrated the enhanced electrocatalytic activity and excellent ability of the 5-aza[5]helicene-CH2O-CO-MWCNTs-modified electrode in the separation between the anodic peaks of epinephrine (EP) and ascorbic acid (AA), even in the presence of a high amount of AA, with a detection limit (S/N = 3) of 5 µmol l-1.

Investigations on the effect of gamma-ray irradiation on the gas sensing properties of SnO2 nanoparticles.

In recent years, SnO2 nanoparticles (NPs) have been subjected to various modifications in order to improve their performance in sensing and other applications. Here, we report the synthesis of SnO2 NPs by microwave irradiation, and subsequent exposure to gamma (γ) radiation at different doses (0-150 kGy) to induce desirable physico-chemical properties. The irradiated samples were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM and HR-TEM), and photoluminescence (PL) to evaluate the effect of γ-ray irradiation on their morphology and microstructure. The results revealed that the bulk crystal structure remained unchanged after irradiation, while the existence of defects and a damaged over-layer have been confirmed by PL and HR-TEM respectively. The influence of γ-irradiation on the electrical and CO sensing characteristics was also investigated in the temperature range between 150 and 400 °C. γ-irradiated SnO2 NP based resistive sensors showed better CO sensing characteristics (i.e. higher response and lower working temperature) compared to non-irradiated SnO2. Upon optimizing the γ-ray dose irradiation level and working temperature, a ten-fold enhancement in the response to CO has been achieved (R/R 0 = 12 to 50 ppm of CO in air) in 50 kGy irradiated SnO2 NP based sensors operating at 150 °C. A possible mechanism for the enhanced sensing performance of γ-irradiated SnO2 NPs has been proposed.

Germinal mosaicism for a deletion of the FMR1 gene leading to fragile X syndrome.

Aberrant CGG trinucleotide amplification within the FMR1 gene, which spans approximately 38 Kb of genomic DNA is almost always what leads to fragile X syndrome (FXS). However, deletions of part or the entire FMR1 gene can also cause FXS. Both CGG amplification-induced silencing and deletions result in the absence of the FMR1 gene product, FMRP. Here, we report a rare case of germinal mosaicism of a deletion encompassing approximately 300 Kb of DNA, which by removing the entire FMR1 gene led to FXS. The male proband, carrying the deletion, presented in clinic with the typical features of FXS. His mother was analyzed by FISH on metaphase chromosomes with cosmid probe c22.3 spanning the FMR1 locus, and she was found not to carry the deletion on 30 analyzed cells from peripheral blood lymphocytes. Prenatal examination of the mother's third pregnancy showed that the male fetus also had the same deletion as the proband. Following this prenatal diagnosis, FISH analysis in the mother was expanded to 400 metaphases from peripheral lymphocytes, and a heterozygous FMR1 deletion was found in three. Although this result could be considered questionable from a diagnostic point of view, it indicates that the deletion is in the ovary's germinal cells.

Italian neurologists' perception on cognitive symptoms in major depressive disorder.

The assessment of cognition is an important part of major depressive disorder (MDD) evaluation and a crucial issue is the physicians' perception of cognitive dysfunction in MDD that remains nowadays a little known matter. The present study aims at investigating the understanding of neurologists' perception about cognitive dysfunction in MDD. An on-line survey addressed to 85 Italian neurologists in the period between May and June 2015 was performed. The questionnaire comprised three sections: the first section collecting information on neurologists' socio-demographic profile, the second investigating cognitive symptoms relevance in relation with different aspects and the third one explicitly focusing on cognitive symptoms in MDD. Cognitive symptoms are considered most significant among DSM-5 symptoms to define the presence of a Major Depressive Episode in a MDD, to improve antidepressant therapy adherence, patients' functionality and concurrent neurological condition, once resolved. Furthermore, an incongruity came to light from this survey: the neurologists considered cognitive symptoms a not relevant aspect to choose the antidepressant treatment in comparison with the other DSM-5 symptoms on one side, but they declared the opposite in the third part of the questionnaire focused on cognitive symptoms. Cognitive symptoms appeared to be a relevant aspect in MDD and neurologists have a clear understanding of this issue. Nevertheless, the discrepancy between neurologists' perception on cognitive symptoms and the antidepressant treatment highlights the feeling of an unmet need that could be filled increasing the awareness of existing drugs with pro-cognitive effects.

A novel disposable electrochemical sensor for determination of carbamazepine based on Fe doped SnO2 nanoparticles modified screen-printed carbon electrode.

An effective strategy to fabricate a novel disposable screen printing carbon electrode modified by iron doped tin dioxide nanoparticles for carbamazepine (CBZ) detection has been developed. Fe-SnO2 (Fe=0 to 5 wt.%) NPs were synthesized by a simple microwave irradiation method and assessed for their structural and morphological changes due to Fe doping into SnO2 matrix by X-ray diffraction and scanning and transmission electron microscopy. The electrochemical behaviour of carbamazepine at the Fe-SnO2 modified screen printed carbon electrode (SPCE) was investigated by cyclic voltammetry and square wave voltammetry. Electron transfer coefficient α (0.63) and electron transfer rate constant ks (0.69 s(-1)) values of the 5 wt.% Fe-SnO2 modified SPCE indicate that the diffusion controlled process takes place on the electrode surface. The fabricated sensor displayed a good electrooxidation response towards the detection of CBZ at a lower oxidation potential of 0.8 V in phosphate buffer solution at pH7.0. Under the optimal conditions, the sensor showed fast and sensitive current response to CBZ over a wide linear range of 0.5-100 µM with a low detection limit of 92 nM. Furthermore, the practical application of the modified electrode has been investigated by the determination of CBZ in pharmaceutical products using standard addition method.

A comparison of the ethanol sensing properties of α-iron oxide nanostructures prepared via the sol-gel and electrospinning techniques.

Haematite (α-Fe2O3) nanostructures were synthesized via a Pechini sol-gel method (PSG) and an electrospinning (ES) technique. Their texture and morphology were investigated by scanning and transmission electron microscopy. α-Fe2O3 nanoparticles were obtained by the PSG method, whereas fibrous structures consisting of interconnected particles were synthesized through the ES technique. The crystallinity of the α-Fe2O3 nanostructures was also studied by means of x-ray diffraction and Raman spectroscopy. Gas-sensing devices were fabricated by printing the synthesized samples on ceramic substrates provided with interdigitated Pt electrodes. The sensors were tested towards low concentrations of ethanol in air in the temperature range (200-400 °C). The results show that the α-Fe2O3 nanostructures exhibit somewhat different gas-sensing properties and, interestingly, their sensing behaviour is strongly temperature-dependent. The availability of active sites for oxygen chemisorption and the diffusion of the analyte gas within the sensing layer structure are hypothesized to be the key factors responsible for the different sensing behaviour observed.

Engineering of carbon based nanomaterials by ring-opening reactions of a reactive azlactone graphene platform.

A reactive azlactone-based graphene nanoplatform was successfully synthesized by the ligation of azido-azlactone with alkyne-terminated graphene via Cu(I)-catalyzed cycloaddition. The reactive azlactone rings, grafted on graphene sheets, were subjected to highly efficient ring-opening reactions with functionalized primary amine derivatives incorporating an aminosilane coupling agent or a biological fragment.

Novel nanosynthesis of In2O3 and its application as a resistive gas sensor for sevoflurane anesthetic.

A novel non-aqueous sol-gel route for synthesizing pure indium oxide (In2O3) nanoparticles (NPs) using indium acetylacetonate and n-butylamine as the reactive solvent, under solvothermal conditions, is herein proposed. The samples were characterized by an advanced X-ray method, whole powder pattern modeling (WPPM) and high-resolution transmission electron microscopy (HR-TEM), showing the exclusive presence of pure In2O3. Diffuse reflectance spectroscopy (DRS) was used to determine the optical band gap (Eg) of the sample. Moreover, these investigations also revealed that the In2O3 nanoparticles are quasi-spherical in shape, with a diameter of around 7 nm as prepared and 9.5 nm after thermal treatment at 250 °C. In2O3 NPs worked as highly sensitive sensing interfaces to provide resistance changes during exposure to sevoflurane, a volatile anesthetic agent used in surgical wards. The developed sensor demonstrated a good response and fast response/recovery time towards very low concentrations of sevoflurane in air, suggesting a very attractive application as a real-time monitoring analyzer in a hospital environment.

Fabrication of folic acid sensor based on the Cu doped SnO2 nanoparticles modified glassy carbon electrode.

A novel folic acid biosensor has been fabricated using Cu doped SnO2 nanoparticles (NPs) synthesized by a simple microwave irradiation method. Powder XRD and TEM studies confirmed that both the pure and Cu doped SnO2 (Cu: 0, 10, 20wt%) crystallized in tetragonal rutile-type structure with spherical morphology. The average crystallite size of pure SnO2 was estimated to be around 16 nm. Upon doping, the crystallite sizes decreased to 9 nm and 5 nm for 10 and 20wt% Cu doped SnO2 respectively. XPS studies confirmed the electronic state of Sn and Cu to be 4+ and 2+ respectively. Cu (20wt%) doped SnO2 NPs are proved to be a good sensing element for the determination of folic acid (FA). Cu-SnO2 NPs (20wt%) modified glassy carbon electrode (GCE) exhibited the lowest detection limit of 0.024 nM over a wide folic acid concentration range of 1.0 × 10(-10) to 6.7 × 10(-5) M at physiological pH of 7.0. The fabricated sensor is highly selective towards the determination of FA even in the presence of a 100 fold excess of common interferent ascorbic acid. The sensor proved to be useful for the estimation of FA content in pharmaceutical sample with satisfactory recovery.

Impact of mast cells on the skin.

When through the skin a foreign antigen enters it provokes an immune response and inflammatory reaction. Mast cells are located around small vessels that are involved in vasaldilation. They mature under the influence of local tissue to various cytokines. Human skin mast cells play an essential role in diverse physiological and pathological processes and mediate immediate hypersensitive reaction and allergic diseases. Injection of anti-IgE in the skin or other agents that directly activate mast cells may cause the decrease in vascular tone, leakage of plasma and may lead to a fall in blood pressure with fatal anaphylactic shock. Skin mast cells are also implicated as effector cells in response to multiple parasites such as Leishmania which is primarily characterized by its tissue cutaneous tropism. Activated macrophages by IFNgamma, cytotoxic T cells, activated mast cells and several cytokines are involved in the elimination of the parasites and immunoprotection. IL-33 is one of the latest cytokines involved in IgE-induced anaphylaxis and in the pathogenesis of allergic skin disorders. IL-33 has been shown in epidermis of patients with psoriasis and its skin expression causes atopic dermatitis and it is crucial for the development of this disease. Here we review the impact of mast cells on the skin.