Short Peptide and Amino Acid-Based Supramolecular Ionogels and Eutectogels.

The capability of peptide and amino acid-based molecules to act as ionogelators and eutectogelators entrapping ionic liquids (ILs) and deep eutectic solvents (DESs) forming ionogels and eutectogels has gathered attention in recent decades. The self-assembly process, primarily driven by non-covalent interactions as hydrogen bonding, remains serendipitous in nature. This review provides a comprehensive and detailed report on self-assembly of unmodified and modified amino acids and peptides in the non-conventional solvents, ILs and DESs. Understanding these processes holds great promise for the development of innovative soft-materials, and to the progress of supramolecular systems in non-conventional solvent environments.

Impact of the Cationic Moiety of Ionic Liquids on Chemoselective Artificial Olfaction.

Ionogels and derived materials are assemblies of polymers and ionic liquids characterized by high stability and ionic conductivity, making them interesting choices as gas sensors. In this work, we assessed the effect of the ionic liquid moiety to generate ionogels and hybrid gels as electrical and optical gas sensors. Six ionic liquids consisting of a constant anion (chloride) and distinct cationic head groups were used to generate ionogels and hybrid gels and further tested as gas sensors in customized electronic nose devices. In general, ionogel-based sensors yielded higher classification accuracies of standard volatile organic compounds when compared to hybrid material-based sensors. In addition, the high chemical diversity of ionic liquids is further translated to a high functional diversity in analyte molecular recognition and sensing.

Synergy between silk fibroin and ionic liquids for active gas-sensing materials.

Silk fibroin is a biobased material with excellent biocompatibility and mechanical properties, but its use in bioelectronics is hampered by the difficult dissolution and low intrinsic conductivity. Some ionic liquids are known to dissolve fibroin but removed after fibroin processing. However, ionic liquids and fibroin can cooperatively give rise to functional materials, and there are untapped opportunities in this combination. The dissolution of fibroin, followed by gelation, in designer ionic liquids from the imidazolium chloride family with varied alkyl chain lengths (2-10 carbons) is shown here. The alkyl chain length of the anion has a large impact on fibroin secondary structure which adopts unconventional arrangements, yielding robust gels with distinct hierarchical organization. Furthermore, and due to their remarkable air-stability and ionic conductivity, fibroin ionogels are exploited as active electrical gas sensors in an electronic nose revealing the unravelled possibilities of fibroin in soft and flexible electronics.

Tackling Humidity with Designer Ionic Liquid-Based Gas Sensing Soft Materials.

Relative humidity is simultaneously a sensing target and a contaminant in gas and volatile organic compound (VOC) sensing systems, where strategies to control humidity interference are required. An unmet challenge is the creation of gas-sensitive materials where the response to humidity is controlled by the material itself. Here, humidity effects are controlled through the design of gelatin formulations in ionic liquids without and with liquid crystals as electrical and optical sensors, respectively. In this design, the anions [DCA]- and [Cl]- of room temperature ionic liquids from the 1-butyl-3-methylimidazolium family tailor the response to humidity and, subsequently, sensing of VOCs in dry and humid conditions. Due to the combined effect of the materials formulations and sensing mechanisms, changing the anion from [DCA]- to the much more hygroscopic [Cl]- , leads to stronger electrical responses and much weaker optical responses to humidity. Thus, either humidity sensors or humidity-tolerant VOC sensors that do not require sample preconditioning or signal processing to correct humidity impact are obtained. With the wide spread of 3D- and 4D-printing and intelligent devices, the monitoring and tuning of humidity in sustainable biobased materials offers excellent opportunities in e-nose sensing arrays and wearable devices compatible with operation at room conditions.

Homeobox gene amplification and methylation in oral squamous cell carcinoma.

OBJECTIVES: Investigate the DNA copy number and the methylation profile of the homeobox genes HOXA5, HOXA7, HOXA9, HOXB5, HOXB13, HOXC12, HOXC13, HOXD10, HOXD11, IRX4 and ZHX1, and correlate them with clinicopathological parameters and overall survival. MATERIAL AND METHODS: DNA from OSCC samples and surgical margins were submitted to DNA amplification by qPCR and to DNA methylation analysis using a DNA Methylation PCR Array System. RESULTS: HOXA5, HOXB5 and HOXD10 were amplified in surgical margins while HOXA9, HOXB13 and IRX4 were amplified in OSCC. HOXD10 demonstrated hypermethylation in half of the tumor while ZHX1 did not show hypermethylation. No correlation of DNA copy number or methylation with clinicopathological parameters or survival was observed. CONCLUSION: HOXA9, HOXB13 and IRX4 genes appears to be regulated by amplification and HOXD10 by methylation in OSCC. Further studies are needed to determine the role of these events in OSCC development.

Versatile and Tunable Poly(Ethylene Glycol)-Based Hydrogels Crosslinked through the Ugi Reaction.

The four-component Ugi condensation reaction has been investigated to assemble chemically crosslinked hydrogels using multivalent star-shaped poly(ethylene glycol) components. The resulting biocompatible hydrogels are highly versatile in composition and function. It is shown that acid, aldehyde, and cyanide components can be varied yielding materials with precise structure and tunable stiffness. Additionally, the resulting hydrogels were proven extremely robust to consecutive drying-swelling cycles. This property was explored to develop a reversible humidity colorimetric sensor gel. Overall, this work demonstrates the application of the four-component Ugi reaction as a powerful tool to quickly generate crosslinked gels with precise control in chemical composition.

Seeing the Unseen: The Role of Liquid Crystals in Gas-Sensing Technologies.

Fast, real-time detection of gases and volatile organic compounds (VOCs) is an emerging research field relevant to most aspects of modern society, from households to health facilities, industrial units, and military environments. Sensor features such as high sensitivity, selectivity, fast response, and low energy consumption are essential. Liquid crystal (LC)-based sensors fulfill these requirements due to their chemical diversity, inherent self-assembly potential, and reversible molecular order, resulting in tunable stimuliresponsive soft materials. Sensing platforms utilizing thermotropic uniaxial systems-nematic and smectic-that exploit not only interfacial phenomena, but also changes in the LC bulk, are demonstrated. Special focus is given to the different interaction mechanisms and tuned selectivity toward gas and VOC analytes. Furthermore, the different experimental methods used to transduce the presence of chemical analytes into macroscopic signals are discussed and detailed examples are provided. Future perspectives and trends in the field, in particular the opportunities for LC-based advanced materials in artificial olfaction, are also discussed.

Differences of megalopapilla and normal sized disk with age-an optical coherence tomography analysis.

PURPOSE: To compare the optic disks of children and adults with megalopapilla using optical coherence tomography (OCT). SUBJECTS AND METHODS: We conducted a case-control study of subjects with megalopapilla and normal sized disks seen between February 2013 and July 2015 at the Hospital da Luz, Lisbon. All subjects and controls were imaged with spectral domain OCT, and optic nerve head (ONH) parameters were evaluated. The main outcome measures were rim area, cup:disk ratio, and cup volume. RESULTS: A total of 168 eyes of 168 subjects were included: 78 with megalopapilla (39 children/39 adults) and 90 (45/45) with normal sized disks. For the same ONH area, children had a higher rim area (P = 0.000), a smaller cup:disk ratio (P = 0.001), and a smaller cup volume (P = 0.001) than adults. For the same age group, megalopapilla had a larger cup:disk ratio (P = 0.000) and a larger cup volume (P = 0.000) than normal-sized disks. CONCLUSIONS: In this study cohort, compared to adults with the same disk size, children (with megalopapilla or normal-sized disks) had a larger rim area and smaller cup. These findings suggest that enlargement of the cup of the optic disk and reduction of the rim area can occur through life.

Predictability of different calculators in the minimization of postoperative astigmatism after implantation of a toric intraocular lens.

PURPOSE: To assess the efficacy of five calculators for toric intraocular lenses (IOL). METHODS: Retrospective comparative case series in cataract patients undergoing implantation of trifocal toric IOLs (PhysIOL FineVision POD FT). Inclusion criteria were age-related cataract and a corneal astigmatism between 0.90D and 4.50D. Refractive astigmatism predictability of five different toric calculators or calculation methods were compared. Furthermore, two groups were differentiated according to the type of astigmatism. The mean absolute error and the centroid errors in the predicted residual astigmatism from each calculator were evaluated. RESULTS: Fifty-one eyes of 43 patients were included in the study. For the standard toric calculator using anterior keratometry values only, the centroid prediction error was 0.39D±0.41@166º, which was reduced by the application of the PhysIOL toric calculator that includes the Abulafia-Koch regression formula and adjustment for the effective lens position (0.05D±0.34@167º), and also by the application of the Barrett toric calculator (0.07D±0.28@160º). Regarding the techniques that directly evaluate posterior corneal surface, the Holladay toric calculator, using total corneal power provided by a color-LED topographer, generated better results (0.10D±0.44@156º) than those using Scheimpflug camera data (0.23D±0.56@158º). Similar results were found for both types of astigmatism. CONCLUSION: The PhysIOL and the Barrett toric calculators taking into account the posterior corneal astigmatism by mathematical models, yielded lower astigmatic prediction errors compared to a standard toric calculator based on anterior keratometry data only. When total corneal power measurements were used, prediction errors were lower with color-LED than with Scheimpflug based topography.

Effect of film thickness in gelatin hybrid gels for artificial olfaction.

Artificial olfaction is a fast-growing field aiming to mimic natural olfactory systems. Olfactory systems rely on a first step of molecular recognition in which volatile organic compounds (VOCs) bind to an array of specialized olfactory proteins. This results in electrical signals transduced to the brain where pattern recognition is performed. An efficient approach in artificial olfaction combines gas-sensitive materials with dedicated signal processing and classification tools. In this work, films of gelatin hybrid gels with a single composition that change their optical properties upon binding to VOCs were studied as gas-sensing materials in a custom-built electronic nose. The effect of films thickness was studied by acquiring signals from gelatin hybrid gel films with thicknesses between 15 and 90 µm when exposed to 11 distinct VOCs. Several features were extracted from the signals obtained and then used to implement a dedicated automatic classifier based on support vector machines for data processing. As an optical signature could be associated to each VOC, the developed algorithms classified 11 distinct VOCs with high accuracy and precision (higher than 98%), in particular when using optical signals from a single film composition with 30 µm thickness. This shows an unprecedented example of soft matter in artificial olfaction, in which a single gelatin hybrid gel, and not an array of sensing materials, can provide enough information to accurately classify VOCs with small structural and functional differences.

Enhanced Gas Sensing with Soft Functional Materials.

The materials described in this work result from the self-assembly of liquid crystals and ionic liquids into droplets, stabilized within a biopolymeric matrix. These systems are extremely versatile gels, in terms of composition, and offer potential for fine tuning of both structure and function, as each individual component can be varied. Here, the characterization and application of these gels as sensing thin films in gas sensor devices is presented. The unique supramolecular structure of the gels is explored for molecular recognition of volatile organic compounds (VOCs) by employing gels with distinct formulations to yield combinatorial optical and electrical responses used in the distinction and identification of VOCs.

Embryonic stem cells markers Oct4 and Nanog correlate with perineural invasion in human salivary gland mucoepidermoid carcinoma.

BACKGROUND: Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy and is successfully treated by surgery and radiation. However, some patients have recurrent tumours and in these cases, few treatments options are available. Cancer stem cells (CSC) have been observed and isolated from different solid tumours based on the expression of stem cell markers. These cells are associated with tumour initiation, progression as well as treatment resistance. In this study, the expression of stem cell markers CD44, Bmi1, Oct4 and Nanog was evaluated in non-neoplastic salivary tissue and in MEC. METHODS: Twenty-eight samples of MEC and their corresponding non-neoplastic salivary tissue were examined by immunohistochemistry and the stem cell markers expression was correlated with histological and clinical parameters. RESULTS: CD44 was expressed in the membrane of serous and mucous acini as well as in the ductal cells in normal gland tissue. Bmi1, Oct4 and Nanog were mainly expressed in ductal structures. In MEC, CD44 and Bmi1 showed strong expression in all types of neoplastic cells and both markers revealed intense expression in tumour invasive front. Oct4 and Nanog protein expression was associated with desmoplasia and perineural invasion. Only Oct4 positive tumours were associated with dissociative growth pattern and committed margins. CONCLUSION: The stem cell markers CD44, Bmi1, Oct4 and Nanog are frequently expressed in MEC in relation to normal salivary gland and Oct4 and Nanog expression may contribute to aggressiveness and worst prognosis in MEC patients.

Fatal hepatocellular carcinoma presenting with oral metastasis in a patient with synchronic primary malignancies of prostate and liver.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most frequent type of liver cancer and its occurrence in the oral cavity as a metastatic neoplasm is a rare event. We describe a fatal case of HCC with oral metastasis in a patient firstly diagnosed with prostatic and hepatic carcinomas. The histopathological examination revealed a hepatocyte-like tumour cells arranged in organoid structures as well as positivity to cytokeratin 8 and Hep Par 1. The present findings highlight the importance of a complete medical evaluation of the patient to identify possible oral repercussions of primary diseases.

Methylation status of homeobox genes in common human cancers.

Approximately 300 homeobox loci were identified in the euchromatic regions of the human genome, of which 235 are probable functional genes and 65 are likely pseudogenes. Many of these genes play important roles in embryonic development and cell differentiation. Dysregulation of homeobox gene expression is a frequent occurrence in cancer. Accumulating evidence suggests that as genetics disorders, epigenetic modifications alter the expression of oncogenes and tumor suppressor genes driving tumorigenesis and perhaps play a more central role in the evolution and progression of this disease. Here, we described the current knowledge regarding homeobox gene DNA methylation in human cancer and describe its relevance in the diagnosis, therapeutic response and prognosis of different types of human cancers.

Ovariectomy-associated changes in interradicular septum and in tibia metaphysis in different observation periods in rats.

In order to standardize an experimental model to study the effects of absence of ovarian hormones in maxillary bones compared with long bones, the aim of this research was to analyze the influence of ovariectomy (OVX) on rat alveolar bone and tibiae, in different observation periods. Thirty-six female rats were ovariectomized or sham operated. After 60, 90 or 120 days, the animals were sacrificed and their hemimandibles, maxillae and tibiae were removed and routinely prepared for hematoxylin and eosin staining. The percentage of bone matrix area in bone septum in the first molar furcation region, and in tibial metaphysis was calculated, and data were submitted to statistical analysis (p<0.05). As regards the histomorphometrical analysis in jaw bones, there was no statistical difference between groups, while the effects of ovariectomy on tibiae were seen as early as 60 days. According to the methods used, there was no significant influence of absence of ovarian hormones on interradicular septum of mandibular or maxillary first molars in the periods studied, despite the reduction in bone matrix area in tibia metaphysis as early as 60 days.

In vitro and in vivo behaviour of sympatric Leishmania (V.) braziliensis, L. (V.) peruviana and their hybrids.

Leishmania (Viannia) braziliensis is the main cause of highly disfiguring mucocutaneous leishmaniasis (MCL) in South America. The related species L. (V.) peruviana has only been identified in simple cutaneous lesions (CL). Hybrids between L. braziliensis and L. peruviana have been reported although genetic exchange in Leishmania is considered to be rare. Here we compared growth in vitro, adaptive capacity under thermal and oxidative stress and behaviour in a hamster model, of L. braziliensis, L. peruviana, and their putative hybrids. At 24°C, the optimal temperature for in vitro growth, L. braziliensis had the highest growth rate. In in vitro studies hybrid clones presented heterogeneous phenotypes, from slower growth rates, similar to L. peruviana, to higher growth rates, as observed in L. braziliensis. Hamsters infected with hybrid strains, presented the highest parasite densities and aggressive relapses at a later stage of infection. Hybrids generally presented higher plasticity and phenotypic diversity than the putative parental species, with potential eco-epidemiological implications, including an impact on the success of disease control.