Quantum-chemical studies of the interaction of partially oxidized graphene-like planes with each other

Using the methods of quantum chemistry, the energy effects of the interaction of partially oxidized graphene-like planes with each other and the effect on this characteristic of the nature of the functional groups present in the oxidized graphene-like planes, as well as the dimensions of the graphene-like planes themselves, were clarified. It was established that the reaction between the hydroxyl and aldehyde groups of two interacting graphene-like planes is the most thermodynamically probable, regardless of the dimensions of the graphene-like planes. The reaction between two carboxyl groups of different graphene-like planes is the least thermodynamically probable. To create nanocomposites by interacting graphene-like planes with each other, it is necessary that the graphene-like planes contain hydroxyl and aldehyde groups

Characterisation of proteins in excretory/secretory products collected from salmon lice, Lepeophtheirus salmonis

Background  The salmon louse, Lepeophtheirus salmonis, is an ectoparasitic copepod which feeds on the mucus, skin and blood of salmonid fish species. The parasite can persist on the surface of the fish without any effective control being exerted by the host immune system. Other ectoparasitic invertebrates produce compounds in their saliva, excretions and/or secretions which modulate the host immune responses allowing them to remain on or in the host during development. Similarly, compounds are produced in secretions of L. salmonis which are thought to be responsible for immunomodulation of the host responses as well as other aspects of crucial host-parasite interactions.  Methods  In this study we have identified and characterised the proteins in the excretory/secretory (E/S) products of L. salmonis using LC-ESI-MS/MS.  Results  In total 187 individual proteins were identified in the E/S collected from adult lice and pre-adult sea lice. Fifty-three proteins, including 13 serine-type endopeptidases, 1 peroxidase and 5 vitellogenin-like proteins were common to both adult and pre-adult E/S products. One hundred and seven proteins were identified in the adult E/S but not in the pre-adult E/S and these included serine and cysteine-type endopeptidases, vitellogenins, sphingomyelinase and calreticulin. A total of 27 proteins were identified in pre-adult E/S products but not in adult E/S.  Conclusions  The assigned functions of these E/S products and the potential roles they play in host-parasite interaction is discussed

Larval pufferfish protected by maternal tetrodotoxin

Marine pufferfish contain tetrodotoxin (TTX), an extremely potent neurotoxin. All species of the genus Takifugu accumulate TTX in the liver and ovaries, although the tissue(s) in which it is localized can differ among species. TTX is the major defense strategy the pufferfish appears to use against predators. TTX is also used as a male-attracting pheromone during spawning. Here we demonstrate an additional (and unexpected) use of maternal TTX in the early larval stages of the Takifugu pufferfish. Predation experiments demonstrated that juveniles of all the species of fish used as predators ingested pufferfish larvae, but spat them out promptly. Liquid Chromatography-Tandem Mass Spectrometry (LC-MSMS) analysis revealed that the pufferfish larvae contain a small quantity of TTX, which is not enough to be lethal to the predators. Immunohistochemical analysis with anti-TTX monoclonal antibody revealed that the TTX is primarily localized in the body surface of the larvae as a layer of protection. Our study showed the female parent of the Takifugu pufferfish vertically transfers TTX to the larvae through its accumulation in the ovaries, and subsequent localization on the body surface of the larvae

Investigating Bismuth-based Perovskite Solar Cells

University of Minnesota M.S. thesis. December 2019. Major: Chemical Engineering. Advisor: Zhihua Xu. 1 computer file (PDF); 65 pages.Solar Cells are one of the most prominent alternatives for fossil fuels. In recent years perovskite solar cells has gained a lot of attention due to its high photovoltaic performance, low cost and the ease of fabrication. However, one of the drawbacks of perovskite solar cells is the toxic constituent element lead (Pb) in the perovskite structure in the form of ABX3, e.g. methylammonium lead iodide (CH3NH3PbI3). To find an alternative to replace lead (Pb) without changing the established perovskite structure, bismuth (Bi) was investigated on the basis of split-ion approach where a three-layer (Bi2Te2, BiI3, and CH3NH3I) deposition process was formulated to fabricate perovskite structure in the form of CH3NH3BiTeI2. Our novelty resides in a unified approach of studying bismuth telluride as a possible compound which would react with bismuth iodide and then having a three-layer deposition method with methylammonium iodide to form a single crystal structure. The solar cells based on the novel lead-free perovskite material have a power conversion efficiency of 0.06%, open-circuit voltage of 0.46 V and current density of 0.38 mA/cm2. Absorption spectrum were used to identify the optimal annealing temperatures to form the perovskite structure. X-ray diffraction showed few peaks matching to the lead-based perovskite CH3NH3PbI3, which suggests the tetragonal perovskite structure was partially formed. The compositional gradient existing in the thermal evaporated Bi2Te3 thin film might be the major culprit leading to the incomplete formation of perovskite structure

Seasonal variation in toxicity of puffer fish, <em>Arothron immaculatus</em>, <em>Chelonodon patoca</em> and <em>Lagocephalus scleratus</em> along Tamil Nadu coast

231-239Anatomical distribution of toxin in the puffers were studied by mouse bioassay. Presence of Tetrodotoxin was analyzed by UV spectrophotometry, FTIR and fluorescence spectrophotometry. During the study we observed that Arothron immaculatus, Chelonodon patoca were toxic throughout the year, while Lagocephalus scleratus showed slight toxicity in its skin and muscle during the monsoon season and was non-toxic during pre-monsoon and post-monsoon seasons. In Arothron immaculatus, particularly the skin and gonad were mostly toxic. In Chelonodon patoca, gonad was highly toxic while the skin and intestine also showed increase in their toxicity at times. However, in both the toxic species, muscle tissue did not show any toxicity

Molecular prognosticators in clinically and pathologically distinct cohorts of head and neck squamous cell carcinoma-A meta-analysis approach.

Head and neck squamous cell carcinomas (HNSCC) includes multiple subsites that exhibit differential treatment outcome, which is in turn reflective of tumor stage/histopathology and molecular profile. This study hypothesized that the molecular profile is an accurate prognostic adjunct in patients triaged based on clinico-pathological characteristics. Towards this effect, publically available micro-array datasets (n = 8), were downloaded, classified based on HPV association (n = 83) and site (tongue n = 88; laryngopharynx n = 53; oropharynx n = 51) and re-analyzed (Genespring; v13.1). The significant genes were validated in respective cohorts in The Cancer Genome Atlas (TCGA) for correlation with clinico-pathological parameters/survival. The gene entities (n = 3258) identified from HPV based analysis, when validated in TCGA identified the subset specifically altered in HPV+ HNSCC (n = 63), with three genes showing survival impact (RPP25, NUDCD2, NOVA1). Site-specific meta-analysis identified respective differentials (tongue: 3508, laryngopharynx: 4893, oropharynx: 2386); validation in TCGA revealed markers with high incidence (altered in >10% of patients) in tongue (n = 331), laryngopharynx (n = 701) and oropharynx (n = 404). Assessment of these genes in clinical sub-cohorts of TCGA indicated that early stage tongue (MTFR1, C8ORF33, OTUD6B) and laryngeal cancers (TWISTNB, KLHL13 and UBE2Q1) were defined by distinct prognosticators. Similarly, correlation with perineural/angiolymophatic invasion, identified discrete marker panels with survival impact (tongue: NUDCD1, PRKC1; laryngopharynx: SLC4A1AP, PIK3CA, AP2M1). Alterations in ANO1, NUDCD1, PIK3CA defined survival in tongue cancer patients with nodal metastasis (node+ECS-), while EPS8 is a significant differential in node+ECS- laryngopharyngeal cancers. In oropharynx, wherein HPV is a major etiological factor, distinct prognosticators were identified in HPV+ (ECHDC2, HERC5, GGT6) and HPV- (GRB10, EMILIN1, FNDC1). Meta-analysis in combination with TCGA validation carried out in this study emphasized on the molecular heterogeneity inherent within HNSCC; the feasibility of leveraging this information for improving prognostic efficacy is also established. Subject to large scale clinical validation, the marker panel identified in this study can prove to be valuable prognostic adjuncts