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Particulate Matter (PM) dramatically affects the well-being of a growing global population, particularly in urban areas. While air quality control is an important and pressing issue, particulate matter analysis typically focuses on size distribution and concentration, offering limited insights into chemical composition and pollutant sources. This study analyzes PM 10 samples collected from five air quality monitoring stations across the Piedmont region. Specifically, the two of the stations are located in the urban environment of Turin, a city known as one of Europe's most polluted cities. The analysis has been carried out using primarily Raman Spectroscopy (RS) to identify the main PM components, investigate the different PM compositions, and evaluate the chemical and seasonal variations. Scanning Electron Microscopy (SEM) equipped with an Energy Dispersion X-ray spectrophotometer (EDX) has also been used to obtain further information about the elemental composition and the size distribution. Amorphous carbon, nitrate salt, sulfate salt, iron oxides, and quartz are the main compounds found. The results of our study highlight significant differences in the chemical composition of PM 10 , indicating variations in the sources and characteristics of PM. Notably, higher levels of nitrate and sulfate particles are linked respectively to cold and warm seasons. Whereas, amorphous carbon and iron oxides are associated with distinct geographic features at the sampling sites, such as traffic conditions. These findings emphasize the importance of understanding the different sources and characteristics of PM 10 to develop effective air pollution mitigation strategies in the Piedmont region., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Lia Drudi reports financial support was provided by Polytechnic of Turin. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Optical quality bioresorbable materials have been gaining interest in recent years for various interstitial biomedical/medical application. An example of this is when the implant gradually dissolves in the body, providing physiological information over extended periods of time, hence reducing the need for revision surgeries. This study reports for the first time the in-house fabrication of single mode (at 785 nm) calcium phosphate glass (CPG) based bioresorbable optical fibers and investigates their suitability for microvascular blood flow monitoring using diffuse correlation spectroscopy (DCS). Ex vivo experiments in liquid phantom and non-invasive in vivo experiments on the human forearm muscle were conducted using multimode and single mode CPG bioresorbable optical fibers. The retrieved flow index from the correlation curves acquired using CPG fibers was in good agreement with that obtained using standard silica (Si) fibers, both ex vivo and in vivo. The results demonstrate the potential of CPG optical fibers for further exploration., Competing Interests: Turgut Durduran is an inventor on relevant patents (US8082015B2, EP18382664.3A). ICFO has equity ownership in the spin-off company HemoPhotonics S.L. Potential financial conflicts of interest and objectivity of research have been monitored by ICFO’s Knowledge & Technology Transfer Department. No financial conflicts of interest were identified. The authors declare no additional conflicts of interest., (© 2024 Optica Publishing Group.)

We demonstrate the usability of bioresorbable phosphate glass fibers for time-domain diffuse optical spectroscopy (TD-DOS) in the short-wave infrared (SWIR) region of 950-1600 nm, with the use of an InGaAs detector. Bioresorbable fibers for diffuse optics present an exciting prospect due to their ability to be left implanted while retrieving optical properties from deeper regions (few cm) for monitoring treatments. Extending TD-DOS to the SWIR region could be useful to better identify biomarkers such as water, lipids and collagen, given their increase in absorption in this range. We attempt to use the bioresorbable fibers to spectrally identify these biomarkers by measuring a series of biological samples known to contain them, such as porcine muscle, porcine fat and bone. We further validate our measurements by comparing the optical properties of high-scattering solid silicone phantoms retrieved with these bioresorbable fibers with those by a standard Si fiber., Competing Interests: The authors declare no conflict of interest., (© 2024 Optica Publishing Group.)

Calcium phosphate (CaP) glass has recently gained popularity as a promising material for a wide range of biomedical applications. Recent developments have seen CaP glasses moving from a passive implant material to an active degradable material, particularly as a major constituent of bioresorbable photonic devices. This holds great promise in advanced biomedical applications, since the main constituents of CaP glasses are present in the human body. In this review, the progressive advancements in the biomedical applications of calcium phosphate glass-based devices over the past 50 years are discussed. An overview of their role as reinforcing agents and the studies on doping their matrices for ion releasing and drug and gene delivery are reviewed. Recent applications of CaP glass and fibers in soft-tissue engineering and their potential for optical quality bioresorbable devices are then discussed along with the current challenges and potential future directions, emphasizing the promising role of CaP glass in the next generation of biomaterials. Considering their progress and potential in performing several biomedical functionalities over time, CaP glass-based devices hold promise for becoming enabling tools as an implantable, bioresorbable, multifunctional class of devices in future biomedicine.

Calcium phosphate glasses (CPGs) are acquiring great importance in the biomedical field because of their thermomechanical and bioresorbable properties. In this study, optically transparent copper (1 mol %)-doped calcium phosphate glasses (CPGs_Cu) were prepared through the melt-quenching method, and their biocompatibility and antibacterial and antiviral properties were evaluated and compared with undoped CPGs. Biocompatibility was evaluated on murine fibroblast NIH-3T3 cells as a preliminary study of cytocompatibility. The in vitro tests were performed through indirect and direct cytotoxicity analyses by MTT and Alamar Blue assays and supported by electron microscopy observations. Microbiological analyses were performed against the most common Gram-negative and Gram-positive pathogens that cause nosocomial infections: Escherichia coli , Pseudomonas aeruginosa , Klebsiella pneumoniae , Staphylococcus aureus , and the methicillin-resistant Staphylococcus aureus strain. In addition, the bioglass samples were exposed to SARS-CoV-2 to assess their effects on viral survival. The obtained results assessed the biocompatibility of both bioglass types and their ability to reduce the viral load and trap the virus. In addition, Cu 2+ -doped bioglass was found to be antibacterial despite its low content (1 mol %) of copper, making this a promising candidate material for biomedical applications, e.g., surgery probes, drug delivery, and photodynamic therapy., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In this study, a single-step nanosecond laser-induced generation of micro-optical features is demonstrated on an antibacterial bioresorbable Cu-doped calcium phosphate glass. The inverse Marangoni flow of the laser-generated melt is exploited for the fabrication of microlens arrays and diffraction gratings. The process is realized in a matter of few seconds and, by optimizing the laser parameters, micro-optical features with a smooth surface are obtained showing a good optical quality. The tunability of the microlens' dimensions is achieved by varying the laser power, allowing the obtaining of multi-focal microlenses that are of great interest for three-dimensional (3D) imaging. Furthermore, the microlens' shape can be tuned between hyperboloid and spherical. The fabricated microlenses exhibited good focusing and imaging performance and the variable focal lengths were measured experimentally, showing good agreement with the calculated values. The diffraction gratings obtained by this method showed the typical periodic pattern with a first-order efficiency of about 5.1%. Finally, the dissolution characteristics of the fabricated micropatterns were studied in a phosphate-buffered saline solution (PBS, pH = 7.4) demonstrating the bioresorbability of the micro-optical components. This study offers a new approach for the fabrication of micro-optics on bioresorbable glass, which could enable the manufacturing of new implantable optical sensing components for biomedical applications.

Self-assembled nanogratings, inscribed by femtosecond laser writing in volume, are demonstrated in multicomponent alkali and alkaline earth containing alumino-borosilicate glasses. The laser beam pulse duration, pulse energy, and polarization, were varied to probe the nanogratings existence as a function of laser parameters. Moreover, laser-polarization dependent form birefringence, characteristic of nanogratings, was monitored through retardance measurements using polarized light microscopy. Glass composition was found to drastically impact the formation of nanogratings. For a sodium alumino-borosilicate glass, a maximum retardance of 168 nm (at 800 fs and 1000 nJ) could be measured. The effect of composition is discussed based on SiO 2 content, B 2 O 3 /Al 2 O 3 ratio, and the Type II processing window is found to decrease as both (Na 2 O + CaO)/Al 2 O 3 and B 2 O 3 /Al 2 O 3 ratios increase. Finally, an interpretation in the ability to form nanogratings from a glass viscosity viewpoint, and its dependency with respect to the temperature, is demonstrated. This work is brought into comparison with previously published data on commercial glasses, which further indicates the strong link between nanogratings formation, glass chemistry, and viscosity.

In the upcoming space revolutions aiming at the implementation of automated, smart, and self-aware crewless vehicles and reusable spacecraft, sensors play a significant role in the control systems. In particular, fiber optic sensors, with their small footprint and electromagnetic immunity, represent a great opportunity in aerospace. The radiation environment and the harsh conditions in which these sensors will operate represent a challenge for the potential user in the aerospace vehicle design and the fiber optic sensor specialist. We present a review that aims to be a primer in the field of fiber optic sensors in radiation environments for aerospace. We review the main aerospace requirements and their relationship with fiber optics. We also present a brief overview of fiber optics and sensors based on them. Finally, we present different examples of applications in radiation environments for aerospace applications.

Microplastics (MPs) are a heterogeneous group of solid polymers with dimensions <5 mm, which are a widespread contaminant of the environment. Their ubiquitous presence grabbed researchers' attention in the last decade, and the problem of MPs detection and quantification is currently a topic of utmost importance. Most identification and quantification protocols are still based on the visual count, which is an extremely time-consuming and error-prone task due to operator subjectivity. To address such an issue, different software analysis procedures are available, but they mainly rely either on the use of optical microscopy, covering a minimal area for each sample (mm 2 size), or they allow only the identification of the largest particles (>1 mm). Here, a semi-automatic innovative image processing method for quantifying and measuring microplastics on filter membrane substrates is presented and validated, comparing results with data obtained using visual counting performed by an experienced operator. The algorithm was tested with artificially generated microplastic images and samples taken from natural environments. Samples of Borgio Verezzi show cave sediment and Po River water were filtered on a glass filter membrane, and photographs were taken under 365 nm illumination, both without and with Nile Red staining. The proposed image analysis method, implemented in an easy-to-use Python script, was quite accurate and fast (about 10 s/image average processing time), showing an average deviation below 10 %, which is further reduced to about 8 % if the samples are stained with Nile Red., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Nanogratings (NGs) are self-assembled subwavelength and birefringent nanostructures created by femtosecond laser direct writing (FLDW) in glass, which are of high interest for photonics, sensing, five-dimensional (5D) optical data storage, or microfluidics applications. In this work, NG formation windows were investigated in nine commercial glasses and as a function of glass viscosity and chemical composition. The NG windows were studied in an energy-frequency laser parameter landscape and characterized by polarizing optical microscopy and scanning electron microscopy (SEM). Pure silica glass (Suprasil) exhibits the largest NG window, whereas alkali borosilicate glasses (7059 and BK7) present the smallest one. Moreover, the NG formation windows progressively reduced in the following order: ULE, GeO 2 , B33, AF32, and Eagle XG. The NG formation window in glasses was found to decrease with the increase of alkali and alkaline earth content and was correlated to the temperature dependence of the viscosity in these glasses. This work provides guidelines to the formation of NGs in commercial oxide glasses by FLDW.

Ion-exchange in molten nitrate salts containing metal ions (i.e. silver, copper, etc.) represents a well-established technique able to modify the chemical-physical properties of glass materials. It is widely used not only in the field of integrated optics (IO) but also, more recently, in plasmonics due to the possibility to induce the formation of metal nanoparticles in the glass matrix by an ad hoc thermal post-process. In this work, the application of this technology for the realisation of low-cost and stable surface-enhanced Raman scattering (SERS) active substrates, based on soda-lime glass microrods, is reported. The microrods, with a radius of a few tens of microns, were obtained by cutting the end of an ion-exchanged soda-lime fibre for a length less than 1 cm. As ion source, silver nitrate was selected due to the outstanding SERS properties of silver. The ion-exchange and thermal annealing post-process parameters were tuned to expose the embedded silver nanoparticles on the surface of the glass microrods, avoiding the use of any further chemical etching step. In order to test the combined SERS/fluorescence response of these substrates, labelled molecular beacons (MBs) were immobilised on their surface for deoxyribonucleic acid (DNA) detection. Our experiments confirm that target DNA is attached on the silver nanoparticles and its presence is revealed by both SERS and fluorescence measurements. These results pave the way towards the development of low-cost and stable hybrid fibres, in which SERS and fluorescence interrogation techniques are combined in the same optical device., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

The Langmuir-Blodgett technique, in which a layer of nanoparticles is spread at the water/air interface and further transferred onto a solid support, is a versatile approach for the preparation of SERS substrates with a controllable arrangement of hotspots. In a previous work, we demonstrated that fine-tuning the lateral packing and subsequent seed growth of 10 nm gold nanoparticles led to a quasi-resonant enhanced in the SERS signal of a test analyte. Here, we explore further enhancements by modifying the size and shape of the spread gold nanoparticles in order to take advantage of the inherent interparticle repulsion mechanisms present at the interface. We show that the size of the used nanoparticles is also a determinant factor, which cannot be compensated by the subsequent electroless growth. We also show that, although the seeded growth leads to rough hotspots, the sensitivity can be optimized by self-assembling urchin-shaped nanoparticles, with a roughness that is fine-tuned a priori. Our results suggest an intriguing correlation between surface homogeneity and SERS signal enhancement, indicating that regular substrates will have the optimal performance.

We present an experimental characterization of the amplification of sub-nanosecond duration laser pulses at a wavelength of 1538 nm in short custom-made Er:Yb phosphate glass fibers with different core diameters. The fibers vary in their diameter from 100 µm (highly multi-mode) down to 12 µm (single-mode). The peak power, energy per pulse, and spectral shape of the amplified signal are presented. With our input pulses, the measurements show that the large core diameter fibers do not increase the amplification of the 1538 nm signal. We believe this is due to the high re-absorption of the E r 3+ ions in the phosphate fiber. The optimal fiber geometry was found to have a core diameter of 20 µm with a length of 14 cm. The maximum peak power is 8.25 kW, corresponding to a net gain of 10.9 dB, with a pulse duration of 0.7 ns and a repetition rate of 40 kHz.

Bone-tissue regeneration induced by biomimetic bioactive materials is the most promising approach alternative to the clinical ones used to treat bone loss caused by trauma or diseases such as osteoporosis. The goal is to design nanostructured bioactive constructs able to reproduce the physiological environment: By mimicking the natural features of bone tissue, the cell behavior during the regeneration process may be addressed. At present, 3D-printing technologies are the only techniques able to design complex structures avoiding constraints of final shape and porosity. However, this type of biofabrication requires complex optimization of biomaterial formulations in terms of specific rheological and mechanical properties while preserving high biocompatibility. In this work, we combined nano-sized mesoporous bioactive glasses enriched with strontium ions with type I collagen, to formulate a bioactive ink for 3D-printing technologies. Moreover, to avoid the premature release of strontium ions within the crosslinking medium and to significantly increase the material mechanical and thermal stability, we applied an optimized chemical treatment using ethanol-dissolved genipin solutions. The high biocompatibility of the hybrid system was confirmed by using MG-63 and Saos-2 osteoblast-like cell lines, further highlighting the great potential of the innovative nanocomposite for the design of bone-like scaffolds.

Optical fibers have recently attracted a noticeable interest for biomedical applications because they provide a minimally invasive method for in vivo sensing, imaging techniques, deep-tissue photodynamic therapy or optogenetics. The silica optical fibers are the most commonly used because they offer excellent optical properties, and they are readily available at a reasonable price. The fused silica is a biocompatible material, but it is not bioresorbable so it does not decompose in the body and the fibers must be ex-planted after in vivo use and their fragments can present a considerable risk to the patient when the fiber breaks. In contrast, optical fibers made of phosphate glasses can bring many benefits because such glasses exhibit good transparency in ultraviolet-visible and near-infrared regions, and their solubility in water can be tailored by changing the chemical composition. The bioresorbability and toxicity of phosphate glass-based optical fibers were tested in vivo on male laboratory rats for the first time. The fiber was spliced together with a standard graded-index multi-mode fiber pigtail and an optical probe for in vitro pH measurement was prepared by the immobilization of a fluorescent dye on the fiber tip by a sol-gel method to demonstrate applicability and compatibility of the fiber with common fiber optics., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Titania particles doped with various concentrations of Erbium were synthesized by the sol-gel method followed by different heat treatments. The shape and the grain growth of the particles were noticeably affected by the concentration of Erbium and the heat treatment conditions. An infrared emission at 1530 nm, as well as green and red up-conversion emissions at 550 and 670 nm, were observed under excitation at 976 nm from all of the synthesized particles. The emission spectra and lifetime values appeared to be strongly influenced by the presence of the different crystalline phases. This work presents important guidelines for the synthesis of functional Er 3+ -doped titania particles with controlled and tailored spectroscopic properties for photonic applications., Competing Interests: The authors declare no conflict of interest. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript and in the decision to publish the results.

In the last years bioresorbable materials are gaining increasing interest for building implantable optical components for medical devices. In this work we show the fabrication of bioresorbable optical fibers designed for diffuse optics applications, featuring large core diameter (up to 200 μm) and numerical aperture (0.17) to maximize the collection efficiency of diffused light. We demonstrate the suitability of bioresorbable fibers for time-domain diffuse optical spectroscopy firstly checking the intrinsic performances of the setup by acquiring the instrument response function. We then validate on phantoms the use of bioresorbable fibers by applying the MEDPHOT protocol to assess the performance of the system in measuring optical properties (namely, absorption and scattering coefficients) of homogeneous media. Further, we show an ex-vivo validation on a chicken breast by measuring the absorption and scattering spectra in the 500-1100 nm range using interstitially inserted bioresorbable fibers. This work represents a step toward a new way to look inside the body using optical fibers that can be implanted in patients. These fibers could be useful either for diagnostic (e. g. for monitoring the evolution after surgical interventions) or treatment (e. g. photodynamic therapy) purposes. Picture: Microscopy image of the 100 μm core bioresorbable fiber., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Er-doped phosphate glass ceramics were fabricated by melt-quenching technique followed by a heat treatment. The effect of the crystallization on the structural and luminescence properties of phosphate glasses containing Al₂O₃, TiO₂, and ZnO was investigated. The morphological and structural properties of the glass ceramics were characterized by Field Emission-Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), and micro-Raman spectroscopy. Additionally, the luminescence spectra and the lifetime values were measured in order to study the influence of the crystallization on the spectroscopic properties of the glasses. The volume ratio between the crystal and the glassy phases increased along with the duration of the heat treatment. The crystallization of the glass ceramics was confirmed by the presence of sharp peaks in the XRD patterns and different crystal phases were identified depending on the glass composition. Sr(PO₃)₂ crystals were found to precipitate in all the investigated glasses. As evidenced by the spectroscopic properties, the site of the Er 3+ ions was not strongly affected by the heat treatment except for the fully crystallized glass ceramic which does not contain Al₂O₃, TiO₂, and ZnO. An increase of the lifetime was also observed after the heat treatment of this glass. Therefore, we suspect that the Er 3+ ions are incorporated in the precipitated crystals only in this glass ceramic., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript and in the decision to publish the results.

Surfaces contaminated with pathogenic microorganisms contribute to their transmission and spreading. The development of "active surfaces" that can reduce or eliminate this contamination necessitates a detailed understanding of the molecular mechanisms of interactions between the surfaces and the microorganisms. Few studies have shown that, among the different surface characteristics, the wetting properties play an important role in reducing virus infectivity. Here, we systematically tailored the wetting characteristics of flat and nanostructured glass surfaces by functionalizing them with alkyl- and fluoro-silanes. We studied the effects of these functionalized surfaces on the infectivity of Influenza A viruses using a number of experimental and computational methods including real-time fluorescence microscopy and molecular dynamics simulations. Overall, we show that surfaces that are simultaneously hydrophobic and oleophilic are more efficient in deactivating enveloped viruses. Our results suggest that the deactivation mechanism likely involves disruption of the viral membrane upon its contact with the alkyl chains. Moreover, enhancing these specific wetting characteristics by surface nanostructuring led to an increased deactivation of viruses. These combined features make these substrates highly promising for applications in hospitals and similar infrastructures where antiviral surfaces can be crucial.

Optoelectronic devices utilizing graphene have demonstrated unique capabilities and performances beyond state-of-the-art technologies. However, requirements in terms of device quality and uniformity are demanding. A major roadblock towards high-performance devices are nanoscale variations of the graphene device properties, impacting their macroscopic behaviour. Here we present and apply non-invasive optoelectronic nanoscopy to measure the optical and electronic properties of graphene devices locally. This is achieved by combining scanning near-field infrared nanoscopy with electrical read-out, allowing infrared photocurrent mapping at length scales of tens of nanometres. Using this technique, we study the impact of edges and grain boundaries on the spatial carrier density profiles and local thermoelectric properties. Moreover, we show that the technique can readily be applied to encapsulated graphene devices. We observe charge build-up near the edges and demonstrate a solution to this issue.

Infrared spectroscopy is the technique of choice for chemical identification of biomolecules through their vibrational fingerprints. However, infrared light interacts poorly with nanometric-size molecules. We exploit the unique electro-optical properties of graphene to demonstrate a high-sensitivity tunable plasmonic biosensor for chemically specific label-free detection of protein monolayers. The plasmon resonance of nanostructured graphene is dynamically tuned to selectively probe the protein at different frequencies and extract its complex refractive index. Additionally, the extreme spatial light confinement in graphene—up to two orders of magnitude higher than in metals—produces an unprecedentedly high overlap with nanometric biomolecules, enabling superior sensitivity in the detection of their refractive index and vibrational fingerprints. The combination of tunable spectral selectivity and enhanced sensitivity of graphene opens exciting prospects for biosensing., (Copyright © 2015, American Association for the Advancement of Science.)

Future optoelectronic devices and their low-cost roll-to-roll production require mechanically flexible transparent electrodes (TEs) and substrate materials. Indium tin oxide (ITO) is the most widely used TE because of its high optical transmission and low electrical sheet resistance. However, ITO, besides being expensive, has very poor performance under mechanical stress because of its fragile oxide nature. Alternative TE materials have thus been sought. Here we report the development of a multilayer TiO2/Ag/Al-doped ZnO TE structure and an ITO-free polymer solar cell (PSC) incorporating it. Electro-optical performances close to those of ITO can be achieved for the proposed TE and corresponding PSC with an additional advantage in their mechanical flexibility, as demonstrated by the fact that the cell efficiency maintains 94% of its initial value (6.6%) after 400 cycles of bending, with 6 and 3 cm maximum and minimum radii, respectively. Instead of common plastic materials, our work uses a very thin (0.14 mm) flexible glass substrate with several benefits, such as the possibility of high-temperature processes, superior antipermeation properties against oxygen and moisture, and improved film adhesion.

Dehydroepiandrosterone (DHEA) is an endogenous steroid hormone involved in a number of biological actions in humans and rodents, but its effects on renal tissue have not yet been fully understood. The aim of this study is to assess the effect of DHEA treatment on diabetic rats, mainly in relation to renal function and metabolism. Diabetic rats were treated with subcutaneous injections of a 10mg/kg dose of DHEA diluted in oil. Plasma glucose and creatinine, in addition to urine creatinine, were quantified espectophotometrically. Glucose uptake and oxidation were quantified using radioactive glucose, the urinary Transforming Growth Factor β(1) (TGF-β(1)) was assessed by enzyme immunoassay, and the total glutathione in the renal tissue was also measured. The diabetic rats displayed higher levels of glycemia, and DHEA treatment reduced hyperglycemia. Plasmatic creatinine levels were higher in the diabetic rats treated with DHEA, while creatinine clearance was lower. Glucose uptake and oxidation were lower in the renal medulla of the diabetic rats treated with DHEA, and urinary TGF-β(1), as well as total gluthatione levels, were higher in the diabetic rats treated with DHEA. DHEA treatment was not beneficial to renal tissue, since it reduced the glomerular filtration rate and renal medulla metabolism, while increasing the urinary excretion of TGF-β(1) and the compensatory response by the glutathione system, probably due to a mechanism involving a pro-oxidant action or a pro-fibrotic effect of this androgen or its derivatives. In conclusion, this study reports that DHEA treatment may be harmful to renal tissue, but the mechanisms of this action have not yet been fully understood., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Ageing is an inevitable biological process characterized by a general decline in various physiological functions. DHEA and DHEAS levels are maximal between the second and third life decades, then start to decline 2% per year, leaving a residual of 10-20% of the peak production by the eighth decade. Erythrocytes are exposed to frequent oxidative stress due to the oxygen radicals continuously generated by haemoglobin auto-oxidation. We investigated DHEA chronic (10 mg/kg, subcutaneously, for 5 weeks) effects over oxidative stress markers in erythrocytes of male Wistar rats of 3, 13 and 18 month-old. In the 13 month-old group, we found increased lipid peroxidation (LPO), superoxide dismutase (SOD), glutathione-S-transferase and catalase activities when compared to the other age groups. DHEA produced a marked increase in LPO of 13 month-old group when compared to its control. DHEA exerted this pro-oxidant effects in all ages studied, especially in age 13 month-old. It seems that at 13 month-old there would be an important depletion of some specific anti-oxidant in order to determine such susceptibility to DHEA effects. Since this approach allows a minimally invasive assessment, it would be useful as a routine method in human clinical studies investigating DHEA effects during the ageing process., (2009 John Wiley & Sons, Ltd.)

A new technique to design an all-fiber temporal differentiator that has a large bandwidth and an arbitrary differentiation order is proposed and investigated. The proposed temporal differentiator is a special fiber Bragg grating (FBG) that is designed by controlling its magnitude and phase responses with the discrete layer peeling (DLP) method. There are three important features of this technique: 1) the temporal differentiator has an arbitrary magnitude response and a controllable bandwidth; 2) the temporal differentiator can be designed and fabricated with an arbitrary differentiation order that is realized in a single FBG; 3) the required maximum index modulation of the FBG-based differentiator is largely decreased by using a Gaussian windowing function. The use of the proposed technique to design temporal differentiators with a differentiation order up to the fourth and with a bandwidth up to 500 GHz is studied. A proof-of-concept experiment is then carried out. A first- and a second-order temporal differentiator with a bandwidth of 25 GHz are experimentally demonstrated.

Neuropathic pain occurs as a result of peripheral or central nervous system injury. Its pathophysiology involves mainly a central sensitization mechanism that may be correlated to many molecules acting in regions involved in pain processing, such as the spinal cord. It has been demonstrated that reactive oxygen species (ROS) and signaling molecules, such as the serine/threonine protein kinase Akt, are involved in neuropathic pain mechanisms. Thus, the aim of this study was to provide evidence of this relationship. Sciatic nerve transection (SNT) was used to induce neuropathic pain in rats. Western blot analysis of Akt and 4-hydroxy-2-nonenal (HNE)-Michael adducts, and measurement of hydrogen peroxide (H(2)O(2)) in the lumbosacral spinal cord were performed. The main findings were found seven days after SNT, when there was an increase in HNE-Michael adducts formation, total and p-Akt expression, and H(2)O(2) concentration. However, one and 15 days after SNT, H(2)O(2) concentration was raised in both sham (animals that were submitted to surgery without nerve injury) and SNT groups, showing the high sensibility of this ROS to nociceptive afferent stimuli, not only to neuropathic pain. p-Akt also increased in sham and SNT groups one day post injury, but at 3 and 7 days the increase occurred exclusively in SNT animals. Thus, there is crosstalk between intracellular signaling pathways and ROS, and these molecules can act as protective agents in acute pain situations or play a role in the development of chronic pain states.

Optimal demodulation of differential phase-shift keying signals at 10 Gbit/s is experimentally demonstrated using a specially designed structured fiber Bragg grating composed by Fabry-Perot coupled cavities. Bit-error-rate measurements show that, as compared with a conventional Gaussian-shaped filter, our demodulator gives approximately 2.8 dB performance improvement.

A fiber strain sensor based on a p-phase-shifted Bragg grating and an extended cavity diode laser is proposed. Locking the laser frequency to grating resonance by the Pound-Drever-Hall technique results in a strain power spectral density S(epsilon) (f) = (3 x 10(-19) f(-1) +2.6 x 10(-23)) epsilon(2)/Hz in the Fourier frequency range from 1 kHz to 10 MHz (epsilon being the applied strain), corresponding to a minimum sensitivity of 5 pepsilon Hz(-1/2) for frequencies larger than 100 kHz.

Immunosuppression is a life-threatening complication of late cancer stages. In this regard, overproduction in the host plasma of the anti-inflammatory cyclopentenone prostaglandins (CP-PGs), which are strongly antiproliferative at high concentrations, may impair immune function. In fact, lymphoid tissues of tumour-bearing rats accumulated large amounts of CP-PGs while the tumour tissue itself did not. Expression of the CP-PG-induced 72-kDa heat shock protein (hsp70) was elevated in lymphocytes from tumour-bearing animals related to controls. As the capacity for CP-PG uptake by lymphocytes is the same as tumour cells, we investigated whether the latter could overexpress the multidrug resistance-associated protein (MRP1/GS-X pump) which extrudes CP-PGs towards the extracellular space as glutathione S-conjugates. Walker 256 tumour cells extruded 15-fold more S-conjugates than lymphocytes from the same rats (p < 0.001). This did not appear to be related to deficiency in lymphocyte glutathione (GSH) metabolism, since the major GSH metabolic routes are consistent with CP-PG conjugation in lymphocytes. This was not the case, however, for the MRP1/GS-X pump activity in lymphocyte membranes (in pmol/min/mg protein: 3.1 +/- 1.7 from normal rats, 0.2 +/- 0.2 from tumour-bearing animals vs 64.3 +/- 7.0 in tumour cells) which was confirmed by Western blot analysis for MRP1 protein. Transfection of lymphocytes with MRP1 gene completely abolished CP-PG (0-40 microM) toxicity. Taken together, these findings suggest that CP-PG accumulation in lymphocytes may be, at least partially, responsible for cancer immunodeficiency. Clinical approaches for overexpressing MRP1/GS-X pump in lymphocytes could then play a role as a tool for the management of cancer therapeutics., (Copyright 2005 John Wiley & Sons, Ltd.)

We show that, in low-dimensional photonic bandgaps, wave diffraction resulting from localization in the translational-invariant directions is strongly influenced by the photonic band structure of the periodic crystal, leading to new kinds of wave localization. In particular, for a periodic layered structure we show that, close to a bandgap edge, diffraction is enhanced, with a transition from a parabolic diffraction curve-typical of isotropic media and supporting Gaussian beams-to hyperbolic or elliptic diffraction curves. In the last two cases localization in the form of stationary X-shaped or sinc-shaped waves is possible.

We study ray and wave propagation in an elliptical graded-index optical fiber or lens with a twisted axis and show analytically the existence of an instability for both ray trajectories and beam moments in a finite range of axis twist rate embedded within the spatial frequencies of periodically focused rays for the untwisted fiber. By considering the paraxial ray equations and the paraxial wave dynamics in a rotating frame that follows the fiber axis twist, we reduce the dynamical problem of ray trajectories to the classical Blackburn's pendulum, which shows a dynamical instability, corresponding to classical diverging trajectories, due to the competing effects of confining potential, Coriolis force, and centrifugal force. A closed set of linear evolution equations for generalized beam moments are also derived from the paraxial wave equation in the rotating reference frame, revealing the existence of a dynamical moment instability in addition to the trajectory instability. A detailed analysis of beam propagation is presented in case of a Gaussian beam, and different dynamical regimes are discussed.

The proband, a 9-year-old Hispanic female, presented with hair loss, strabismus, and weight gain. On magnetic resonance imaging (MRI) she was found to have severe primary hypothyroidism and a large pituitary mass. In addition, acanthosis nigricans, obesity, and hyperinsulinism were observed. Findings were similar in three of four siblings. Thyroid peroxidase antibodies were detected in the father and three of four siblings. Although all family members were obese, and hyperinsulinemia with high proinsulin and C-peptide was found in all except one sibling, only the mother and one child had overt type 2 diabetes mellitus. Because of the unusual association of autoimmune thyroid disease, insulin resistance and obesity rather than insulin deficiency, we searched for possible genetic abnormalities. The HLA haplotypes did not cosegregate with autoimmune thyroid disease or insulin resistance. Mutational analysis of known obesity genes was done. Leptin was not deficient, and sequencing of the proband's DNA showed no mutations in the perixisome proliferator activated receptor (PPAR)-gamma, PPAR-gamma(2), PPAR-alpha or melanocortin 4 receptor genes. Maternally inherited diabetes and deafness was ruled out since no mutations were found in mitochondria DNA. Insulin receptor antibodies were not detected. In conclusion, the remarkably high incidence of childhood autoimmune hypothyroidism, pituitary enlargement, insulin resistance and obesity in this family is not linked to known HLA types or known gene defects.

We report four fatal cases of amebic encephalitis in children caused by the free-living pathogenic ameba Balamuthia mandrillaris. The clinical course ranged from subacute to fulminant. Provisional diagnoses were made either shortly before death or postmortem by an indirect immunofluorescent antibody test. Although the four cases occurred in different geographic locations, their common features may have diagnostic value for recognizing future cases of amebic encephalitis. The cases occurred in children 2 to 7.5 years old who were ostensibly immunocompetent and of Hispanic ethnicity. Three of the four children developed hydrocephalus during their illness. Increased awareness and timely diagnosis of this disease entity might lead to earlier intervention with improved outcome.