Transparent, plasticized cellulose-glycerol bioplastics for food packaging applications.

Free-standing films have been obtained by drop-casting cellulose-glycerol mixtures (up to 50 wt% glycerol) dissolved in trifluoroacetic acid and trifluoroacetic anhydride (TFA:TFAA, 2:1, v:v). A comprehensive examination of the optical, structural, mechanical, thermal, hydrodynamic, barrier, migration, greaseproof, and biodegradation characteristics of the films was conducted. The resulting cellulose-glycerol blends exhibited an amorphous molecular structure and a reinforced H-bond network, as evidenced by X-ray diffraction analysis and infrared spectroscopy, respectively. The inclusion of glycerol exerted a plasticizing influence on the mechanical properties of the films, while keeping their transparency. Hydrodynamic and barrier properties were assessed through water uptake and water vapor/oxygen transmission rates, respectively, and obtained values were consistent with those of other cellulose-based materials. Furthermore, overall migration levels were below European regulation limits, as stated by using Tenax® as a dry food simulant. In addition, these bioplastics demonstrated good greaseproof performance, particularly at high glycerol content, and potential as packaging materials for bakery products. Biodegradability assessments were carried out by measuring the biological oxygen demand in seawater and high biodegradation rates induced by glycerol were observed.

In Vitro Antimicrobial Photodynamic Therapy for Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) Inhibition Using a Green Light Source.

Photodynamic therapy (PDT) has been based on using photosensitizers (PS) and applying light of a specific wavelength. When this technique is used for treating infections, it is known as antimicrobial photodynamic therapy (aPDT). Currently, the use of lighting sources for in vitro studies using aPDT is generally applied in multiwell cell culture plates; however, depending on the lighting arrangement, there are usually errors in the application of the technique because the light from a well can affect the neighboring wells or it may be that not all the wells are used in the same experiment. In addition, one must be awarded high irradiance values, which can cause unwanted photothermal problems in the studies. Thus, this manuscript presents an in vitro antimicrobial photodynamic therapy for a Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition study using an arrangement of thermally isolated and independently illuminated green light source systems for eight tubes in vitro aPDT, determining the effect of the following factors: (i) irradiance level, (ii) exposure time, and (iii) Rose Bengal (RB) concentration (used as a PS), registering the Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) inhibition rates. The results show that in the dark, RB had a poor antimicrobial rate for P. aeruginosa, finding the maximum inhibition (2.7%) at 30 min with an RB concentration of 3 µg/mL. However, by applying light in a correct dosage (time × irradiance) and the adequate RB concentration, the inhibition rate increased by over 37%. In the case of MRSA, there was no significant inhibition with RB in complete darkness and, in contrast, the rate was 100% for those experiments that were irradiated.

Enhancing the Electrochemical Performance in Symmetrical Solid Oxide Cells through Nanoengineered Redox-Stable Electrodes with Exsolved Nanoparticles.

Symmetrical solid oxide cells (SSOCs) have recently gained significant attention for their potential in energy conversion due to their simplified cell configuration, cost-effectiveness, and excellent reversibility. However, previous research efforts have mainly focused on improving the electrode performance of perovskite-type electrodes through different doping strategies, neglecting microstructural optimization. This work presents novel approaches for the nanostructural tailoring of (La0.8Sr0.2)0.95Fe1-xTixO3-δ (LSFTx, x = 0.2 and 0.4) electrodes using a single-step spray-pyrolysis deposition process. By incorporating these electrodes into a Ce0.9Gd0.1O1.95 (CGO) porous backbone or employing a nanocomposite architecture with nanoscale particle size, we achieved significant improvements in the polarization resistance (Rp) compared with traditional screen-printed electrodes. To further boost the fuel oxidation performance, a Ni-doping strategy, coupled with meticulous microstructural optimization, was implemented. The exsolution of Ni nanoparticles under reducing conditions resulted in remarkable Rp values as low as 0.34 and 0.11 Ω cm2 in air and wet H2 at 700 °C, respectively. Moreover, an electrolyte-supported cell with symmetrical electrodes demonstrated a stable maximum power density of 617 mW cm-2 at 800 °C. These findings highlight the importance of combining electrode composition optimization with advanced morphology control in the design of highly efficient and durable SSOCs.

Design of a Low-Cost Diffuse Optical Mammography System for Biomedical Image Processing in Breast Cancer Diagnosis.

Worldwide, breast cancer is the most common type of cancer that mainly affects women. Several diagnosis techniques based on optical instrumentation and image analysis have been developed, and these are commonly used in conjunction with conventional diagnostic devices such as mammographs, ultrasound, and magnetic resonance imaging of the breast. The cost of using these instruments is increasing, and developing countries, whose deaths indices due to breast cancer are high, cannot access conventional diagnostic methods and have even less access to newer techniques. Other studies, based on the analysis of images acquired by traditional methods, require high resolutions and knowledge of the origin of the captures in order to avoid errors. For this reason, the design of a low-cost diffuse optical mammography system for biomedical image processing in breast cancer diagnosis is presented. The system combines the acquisition of breast tissue photographs, diffuse optical reflectance (as a biophotonics technique), and the processing of digital images for the study and diagnosis of breast cancer. The system was developed in the form of a medical examination table with a 638 nm red-light source, using light-emitted diode technology (LED) and a low-cost web camera for the acquisition of breast tissue images. The system is automatic, and its control, through a graphical user interface (GUI), saves costs and allows for the subsequent analysis of images using a digital image-processing algorithm. The results obtained allow for the possibility of planning in vivo measurements. In addition, the acquisition of images every 30° around the breast tissue could be used in future research in order to perform a three-dimensional (3D) reconstruction and an analysis of the captures through deep learning techniques. These could be combined with virtual, augmented, or mixed reality environments to predict the position of tumors, increase the likelihood of a correct medical diagnosis, and develop a training system for specialists. Furthermore, the system allows for the possibility to develop analysis of optical characterization for new phantom studies in breast cancer diagnosis through bioimaging techniques.

Unraveling the Influence of the Electrolyte on the Polarization Resistance of Nanostructured La0.6Sr0.4Co0.2Fe0.8O3-δ Cathodes.

Large variations in the polarization resistance of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes are reported in the literature, which are usually related to different preparation methods, sintering temperatures, and resulting microstructures. However, the influence of the electrolyte on the electrochemical activity and the rate-limiting steps of LSCF remains unclear. In this work, LSCF nanostructured electrodes with identical microstructure are prepared by spray-pyrolysis deposition onto different electrolytes: Zr0.84Y0.16O1.92 (YSZ), Ce0.9Gd0.1O1.95 (CGO), La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM), and Bi1.5Y0.5O3-δ (BYO). The ionic conductivity of the electrolyte has a great influence on the electrochemical performance of LSCF due to the improved oxide ion transport at the electrode/electrolyte interface, as well as the extended ionic conduction paths for the electrochemical reactions on the electrode surface. In this way, the polarization resistance of LSCF decreases as the ionic conductivity of the electrolyte increases in the following order: YSZ > LSGM > CGO > BYO, with values ranging from 0.21 Ω cm2 for YSZ to 0.058 Ω cm2 for BYO at 700 °C. In addition, we demonstrate by distribution of relaxation times and equivalent circuit models that the same rate-limiting steps for the ORR occur regardless of the electrolyte. Furthermore, the influence of the current collector material on the electrochemical performance of LSCF electrodes is also analyzed.

LaCrO3-CeO2-Based Nanocomposite Electrodes for Efficient Symmetrical Solid Oxide Fuel Cells.

La0.98Cr0.75Mn0.25O3-δ-Ce0.9Gd0.1O1.95 (LCM-CGO) nanocomposite layers with different LCM contents, between 40 and 60 wt %, are prepared in a single step by a spray-pyrolysis deposition method and evaluated as both air and fuel electrodes for solid oxide fuel cells (SOFCs). The formation of fluorite (CGO) and perovskite (LCM) phases in the nanocomposite electrode is confirmed by different structural and microstructural techniques. The intimate mixture of LCM and CGO phases inhibits the grain growth, retaining the nanoscale microstructure even after annealing at 1000 °C with a grain size lower than 50 nm for LCM-CGO compared to 200 nm for pure LCM. The synergetic effect of nanosized LCM and CGO by combining their high electronic and ionic conductivity, respectively, leads to efficient and durable symmetrical electrodes. The best electrochemical properties are found for 50 wt % LCM-CGO, showing polarization resistance values of 0.29 and 0.09 Ω cm2 at 750 °C in air and H2, respectively, compared to 2.05 and 1.9 Ω cm2 for a screen-printed electrode with the same composition. This outstanding performance is mainly ascribed to the nanoscale electrode microstructure formed directly on the electrolyte at a relatively low temperature. These results reveal that the combination of different immiscible phases with different crystal structures and electrochemical properties could be a promising strategy to design highly efficient and durable air and fuel electrodes for SOFCs.

Transparent, UV-blocking, and high barrier cellulose-based bioplastics with naringin as active food packaging materials.

Free-standing, robust, and transparent bioplastics were obtained by blending cellulose and naringin at different proportions. Optical, thermal, mechanical, antioxidant, and antimicrobial properties were systematically investigated. In general, the incorporation of naringin produced important UV blocking and plasticizer effects and good antioxidant and antibacterial properties. Moreover, the barrier properties were characterized by determination of their water and oxygen transmission rates, finding that both parameters decreased by increasing the naringin content and reaching values similar to other petroleum-based plastics and cellulose derivatives used for food packaging applications. Finally, the biodegradability of these films was determined by measurement of the biological oxygen demand (BOD) in seawater, demonstrating an excellent decomposition in such conditions.

Pectin-cellulose nanocrystal biocomposites: Tuning of physical properties and biodegradability.

The fabrication of pectin-cellulose nanocrystal (CNC) biocomposites has been systematically investigated by blending both polysaccharides at different relative concentrations. Circular free-standing films with a diameter of 9 cm were prepared by simple solution of these carbohydrates in water followed by drop-casting and solvent evaporation. The addition of pectin allows to finely tune the properties of the biocomposites. Textural characterization by AFM showed fibrous morphology and an increase in fiber diameter with pectin content. XRD analysis demonstrated that pectin incorporation also reduced the degree of crystallinity though no specific interaction between both polysaccharides was detected, by ATR-FTIR spectroscopy. The optical properties of these biocomposites were characterized for the first time and it was found that pectin in the blend reduced the reflectance of visible light and increased UV absorbance. Thermal stability, analyzed by TGA, was improved with the incorporation of pectin. Finally, pectin-cellulose nanocrystal biocomposites showed a good biodegradability in seawater, comparable to other common bioplastics such as cellulose and low-molecular weight polylactide, among others.

Fluorescence spectroscopy on paraffin-preserved human liver samples to classify several grades of fibrosis.

Nowadays, it is well established that biopsy is the gold standard for medical diagnosis of liver disease; however, recent studies have shown numerous discrepancies in biopsy assessment, even when it is evaluated by senior pathologists. Fluorescence spectroscopy is a tool that has been of utility in the diagnosis of different diseases based on biopsy analysis. Thus, fluorescence study of liver samples with five different degrees of fibrosis is presented. Paraffin-preserved human liver tissue was provided on white plastic cassettes by the Hospital General de Mexico "Dr. Eduardo Liceaga". Specimens were diagnosed by two independent-senior pathologists in a double-blind test and classified into five different groups: F0, F1, F2, F3, and F4, according to the METAVIR scale for liver fibrosis. Fluorescence spectroscopy measurements were performed using three different excitation wavelengths: 385, 405, and 450 nm. Besides, diffuse reflectance spectroscopy (DRS) measurements were taken with white light to determine morphological changes in the tissue and to compare the results with medical diagnosis. The spectral analysis at excitation wavelengths of 385 nm and 405 nm showed poor correlation with medical diagnosis. Likewise, in order to discard all possible error-sources involved in the measurements, an exhaustive study was carried out; it included the determination of the fluorescence noise produced by paraffin, cassette, and the tissue itself. At 450 nm excitation wavelength, no fluorescence by the cassette was detected and noise-subtraction methods were not required, this allows a high correlation of hepatic fibrosis stages between pathological diagnosis and spectroscopic analysis. For this excitation wavelength, 89.87% correlation with DRS measurements and 82.00% with medical diagnosis were obtained. This work demonstrates that fluorescence spectroscopy using 450 nm excitation wavelength might work as a complementary tool to grade hepatic fibrosis in human liver specimens.

Nanostructured BaCo0.4Fe0.4Zr0.1Y0.1O3-δ Cathodes with Different Microstructural Architectures.

Lowering the operating temperature of solid oxide fuel cells (SOFCs) is crucial to make this technology commercially viable. In this context, the electrode efficiency at low temperatures could be greatly enhanced by microstructural design at the nanoscale. This work describes alternative microstructural approaches to improve the electrochemical efficiency of the BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) cathode. Different electrodes architectures are prepared in a single step by a cost-effective and scalable spray-pyrolysis deposition method. The microstructure and electrochemical efficiency are compared with those fabricated from ceramic powders and screen-printing technique. A complete structural, morphological and electrochemical characterization of the electrodes is carried out. Reduced values of area specific resistance are achieved for the nanostructured cathodes, i.e., 0.067 Ω·cm2 at 600 °C, compared to 0.520 Ω·cm2 for the same cathode obtained by screen-printing. An anode supported cell with nanostructured BCFZY cathode generates a peak power density of 1 W·cm-2 at 600 °C.

Synergic Effect of Metal and Fluorine Doping on the Structural and Electrical Properties of La5.4MoO11.1-Based Materials.

Cationic and anionic frameworks of La5.4MoO11.1 proton conductors have been modified by means of metal (Ti4+, Zr4+, and Nb5+) and fluorine (F-) doping. This synergic effect leads to the stabilization of high-symmetry and single-phase polymorphs. The materials have been fully characterized by structural techniques, such as X-ray and neutron powder diffraction and transmission electron microscopy. The fluorine content was determined by ion chromatography. Impedance spectroscopy analysis under different atmospheres (dry and wet N2 and O2 and wet 5% H2-Ar) showed an improvement in the electronic conductivity under reducing conditions, making these materials potential candidates for hydrogen separation membranes.

Metal-Doping of La5.4MoO11.1 Proton Conductors: Impact on the Structure and Electrical Properties.

La5.4MoO11.1 proton conductors with different metal doping (Ca2+, Sr2+, Ba2+, Ti4+, Zr4+, and Nb5+) have been prepared and structurally and electrically characterized. Different polymorphs are stabilized depending on the doping and cooling rate used during the synthesis process. The most interesting results are obtained for Nb-doping, La5.4Mo1- xNb xO11.1- x/2, where single compounds are obtained in the compositional range 0 ≤ x ≤ 0.2. These materials are fully characterized by structural techniques such as X-ray and neutron powder diffraction and transmission electron microscopy, which independently confirm the changes of polymorphism. Scanning electron microscopy and impedance spectroscopy measurements in dry/wet gases (N2, O2, and 5% H2-Ar) showed an enhancement of the sinterability and electrical properties of the materials after Nb-doping. Conductivity measurements under very reducing conditions revealed that these materials are mixed ionic-electronic conductors, making them potential candidates for hydrogen separation membranes.

Fluorescence Spectroscopy as a Tool for the Assessment of Liver Samples with Several Stages of Fibrosis.

BACKGROUND: During the last years, fluorescence spectroscopy has been used as a potential tool for the evaluation and characterization of tissues with different disease conditions due to its low cost, high sensitivity, and minimally or noninvasive character. OBJECTIVE: In this study, fluorescence spectroscopy was used to study 19 paraffin blocks containing human liver tissue from biopsies. METHODS AND RESULTS: All samples were previously analyzed by two senior pathologists in a single-blind trial. After their evaluation, four liver samples were classified as nonfibrosis (F0), four as initial fibrosis (F1-F2), four as advanced fibrosis (F3), and six as cirrhosis (F4). The fluorescence was induced at different wavelengths as follows: 330, 365, and 405 nm using a portable fiber-optic system. The fluorescence spectra were recorded in the range of 400-750 nm. A distinctive correlation between the shape of each spectrum and the level of fibrosis in the liver sample was detected. A multi-variate statistical analysis based on principal component analysis followed by linear discrimination analysis was applied to develop algorithms able to distinguish different stages of fibrosis based on the characteristics of fluorescence spectra. Pairwise comparisons were performed: F0 versus F1-F2, F1-F2 versus F3, F3 versus F4, and F1-F2 versus F4. The algorithms applied to each set of data yielded values of sensitivity and specificity that were higher than 90% and 95%, respectively, in all the analyzed cases. CONCLUSIONS: With this study, it is concluded that fluorescence spectroscopy can be used as a complementary tool for the assessment of liver fibrosis in liver tissue samples, which sets the stage for subsequent clinical trials.

De las escalas de riesgo poblacional a la cuantificación de la ateroesclerosis subclínica: hacia un nuevo paradigma en la predicción cardiovascular / From risk scales to subclinical atherosclerosis quantification through non-invasive imaging: toward a new paradigm in cardiovascular risk prediction

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In Vitro Photoirradiation System for Simultaneous Irradiation with Different Light Doses at a Fixed Temperature.

OBJECTIVE: In this work an irradiance and temperature controlled in-vitro system for conducting investigations in PDT and phototherapy is presented. BACKGROUND DATA: The development of new light sources has caused a considerable increase in research and application of several photodynamic (PDT) therapeutic methods, as well as other light-based therapeutic techniques. However, further work is needed to fully understand and elucidate the mechanisms as well as to increase the effectiveness of PDT. Nowadays, there are no commercial systems to perform automated light exposure experiments with cultured cells. Also, there are very few reports of similar photoirradiation systems. MATERIALS AND METHODS: The system is composed of 24 independent light-emitting diodes that can be used to irradiate separate wells in a microwell plate. The system includes a module to measure changes in temperature within each irradiated well without contact. The light sources are placed on a plate that can easily be changed in order to irradiate at different wavelengths. The performance of the system is fully controlled with a computer, and all the experimental data are properly recorded. RESULTS: The design, construction, operation, and a full characterization of the system are presented. CONCLUSIONS: A novel fully automated photoirradiation system has been developed. The system allows the design of the experiments in this area with precise dosimetry, temperature, and irradiation regime controls reducing manipulation of the samples and saving time.

Magnetic resonance imaging study in a normal Bengal tiger (Panthera tigris) stifle joint.

BACKGROUND: The purpose of this study was to describe the normal appearance of the bony and soft tissue structures of the stifle joint of a Bengal tiger (Panthera tigris) by low-field magnetic resonance imaging (MRI), and the use of gross anatomical dissections performed as anatomical reference. A cadaver of a mature female was imaged by MRI using specific sequences as the Spin-echo (SE) T1-weighting and Gradient-echo (GE) STIR T2-weighting sequences in sagittal, dorsal and transverse planes, with a magnet of 0.2 Tesla. The bony and articular structures were identified and labelled on anatomical dissections, as well as on the magnetic resonance (MR) images. RESULTS: MR images showed the bone, articular cartilage, menisci and ligaments of the normal tiger stifle. SE T1-weighted sequence provided excellent resolution of the subchondral bones of the femur, tibia and patella compared with the GE STIR T2-weighted MR images. Articular cartilage and synovial fluid were visualised with high signal intensity in GE STIR T2-weighted sequence, compared with SE T1-weighted sequence where they appeared with intermediate intensity signal. Menisci and ligaments of the stifle joint were visible with low signal intensity in both sequences. The infrapatellar fat pad was hyperintense on SE T1-weighted images and showed low signal intensity on GE STIR T2-weighted images. CONCLUSIONS: MRI provided adequate information of the bony and soft tissues structures of Bengal tiger stifle joints. This information can be used as initial anatomic reference for interpretation of MR stifle images and to assist in the diagnosis of diseases of this region.

Evaluation of the antitumour activity of Rinvanil and Phenylacetylrinvanil on the cervical cancer tumour cell lines HeLa, CaSKi and ViBo.

Capsaicin is a potent inducer of apoptosis in tumourreceptor potential vanilloid 1 (TRPV1). The present study determined the IC50 and cytotoxic and apoptotic activities of the Capsaicin analogues Rinvanil and Phenylacetylrinvanil (PhAR) on three cervical cancer cell lines: HeLa, CaSKi and ViBo. These analogues possess an increased affinity for TRPV1 receptors. The IC50 obtained proved to be cytotoxic for all three cell lines; however, in the cells treated with Capsaicin both active caspase-3 and nuclear fragmentation were present. Capsaicin and its analogues also inhibited the normal proliferation of lymphocytes, suggesting that they are non-selective antitumour compounds. Finally, we discuss the possible loss of the relation between apoptosis and affinity to TRPV1, and the need for other strategies to synthesise Capsaicin analogues that can be useful in cancer treatments.

Prognostic Role of 14F7 Mab Immunoreactivity against N-Glycolyl GM3 Ganglioside in Colon Cancer.

Purpose. To assess the prognostic role of 14F7 Mab immunoreactivity, against N-Glycolyl GM3 ganglioside, in patients with colon cancer (CC) and to evaluate the relationship between its expression and clinicopathological features. Methods. Paraffin-embedded specimens were retrospectively collected from 50 patients with CC operated between 2004 and 2008. 14F7 Mab staining was determined by immunohistochemistry technique and its relation with survival and clinicopathologic features was evaluated. Results. The reactivity of 14F7 Mab was detected in all cases. Most cases had high level of immunostaining (70%) that showed statistical correlation with TNM stage (P = 0.025). In univariate survival analysis, level of 14F7 Mab immunoreactivity (P = 0.0078), TNM Stage (P = 0.0007) and lymphovascular invasion (0.027) were significant prognostic factors for overall survival. Among these variables, level of 14F7 Mab immunoreactivity (HR = 0.268; 95% CI 0.078-0.920; P = 0.036) and TNM stage (HR = 0.249; 95% CI 0.066-0.932; P = 0.039) were independent prognostic factors on multivariate analysis. Conclusions. This study is the first approach on the prognostic significance of 14F7 Mab immunoreactivity in patients with colon adenocarcinoma and this assessment might be used in the prognostic estimate of CC, although further studies will be required to validate these findings.