Carbon nanotube electronic structures as anti-corrosion coatings

A new concept of corrosion prevention is considered in this study. Diode-like and transistor-like structures have been fabricated and analyzed in the study of ionic flow through the resulting potential barriers. The structures were made of functionalized carbon nanotubes. Carbon nanotubes are known for many remarkable properties among which is being chemically inert. Taking advantage of this property, a study of corrosion of steel was undertaken. In the first case study, successive layers of functionalized carbon nanotubes were deposited to form p-n junctions on steel substrates. It was demonstrated that the corrosion was indeed impeded by the potential barrier formed across an electronic p-n junction. Potentiodynamic measurements, Raman spectroscopy, impedance measurements and scanning electron microscopy with energy dispersive x-ray spectroscopy were used to assess the corrosion process. It was found that the layer ordering (p-n or n-p with respect to the metal electrode) determined the corrosion rate in de-ionized (DI) water. Only temporary resistance was found in the presence of 3.5 wt% NaCl solution. In the second case study, functionalized carbon nanotubes were drop-casted layer by layer to obtain transistor like p-n-p or n-p-n junctions. It was observed that the base voltage appreciably controlled the surface potential. The layer ordering determined the direction in which the surface potential of the steel substrate varied. In the third case study, graphene was used as an intermediate layer between the steel substrate and the electronic p-n junctions. Graphene was also used as an intermediate layer between a steel substrate and a conductive polymer (polypyrrole) film. Here it was demonstrated that the monolayer thick graphene had a significant effect on the surface potential of the steel substrate. Also, graphene provided for an additional protection as determined by corrosion experiments. In the fourth case study, bio-compatibility nature of carbon nanotubes was exploited. Single stranded deoxyribose nucleic acid was used to functionalize carbon nanotubes and obtain n-type semiconducting films. Electronic junctions were fabricated using these films as previously noted. The effect of bio-electronic p-n junctions was similar to the first case study, yet, by doing so, the potential for bio-ionic applications is made possible

Avaren-Fc, a Novel Immunotherapeutic, Recruits NK Cells in B16F10 Melanoma Tumor Tissue

Melanoma is the fifth most common cancer in the US, with limited effective immunotherapeutic options available for patients. Avaren-Fc (AvFc) is a novel experimental immunotherapeutic agent with a unique “lectibody” property. It is capable of targeting cancer cells through the selective recognition of high mannose glycans, which are aberrantly overrepresented on the surface of malignant cells. AvFc can interact with circulating effector immune cells equipped with Fc receptors, such as natural killer (NK) cells to induce antibody-dependent cell-mediated cytotoxicity (ADCC) and kill cancer cells. Previous work has shown that AvFc effectively induces ADCC activity against B16F10 cancer cells in vitro. Furthermore, flow cytometry analysis revealed that AvFc treatment exhibited a trend towards increased NK cell infiltration within the B16F10 flank tumor tissue of C57bl/c mice. The objective of the current study is to assess the B16F10 tumor microenvironment by immunohistochemistry, quantifying NK cells and an associated NK cell activation signal in AvFc-treated B16F10 tumor tissue compared to untreated tissue. Based on our previous flow cytometry analysis data, we hypothesized that AvFc-treated tissue may have an elevated NK cell count, indicative of AvFc-mediated recruitment of NK cells. The study utilized fluorescent immunohistochemistry, which probed for NK cells (NK1.1) and NK cell activation (CD107a). The results demonstrated a significant increase in the number of NK-1.1+ cells (p = 0.0056, Wilcoxon Rank Sum Test) and CD107a+ signal (p = 0.0009, Wilcoxon Rank Sum Test) in AvFc-treated tissue when compared to untreated tissue. Colocalization of NK-1.1 and CD107a was also deemed significant in AvFc-treated tissue (p = 0.0032, Wilcoxon Rank Sum Test), thus supporting the presence and associated activation of NK cells in the tumor microenvironment. These results warrant further analysis to elucidate the underlying mechanism by which AvFc recruits additional NK cells to the tumor tissue. Overall, the results from this study corroborate that AvFc’s anti-cancer activity is mediated via NK cell activation and support its development as a potential immunotherapeutic for melanoma treatment

Coupling of proteins to liposomes and their role in understanding delayed type of hypersensitivity in human and mice

Liposome-coupled lepromin was found to elicit a 3-week skin reaction in leprosy patients similar to that elicited by whole Mycobacterium leprae. The present study suggests that the presentation of antigens in a specific orientation is necessary for evoking delayed type hypersensitivity response in humans

A literature review on surgery for cervical vagal schwannomas

Cervical vagal schwannoma is a benign, slow-growing mass, often asymptomatic, with a very low lifetime risk of malignant transformation in general population, but diagnosis is still a challenge. Surgical resection is the treatment of choice even if its close relationship with nerve fibres, from which it arises, threats vagal nerve preservation. We present a case report and a systematic review of literature. All studies on surgical resection of cervical vagal schwannoma have been reviewed. Papers matching the inclusion criteria (topic on surgical removal of cervical vagal schwannoma, English language, full text available) were selected. Fifty-three patients with vagal neck schwannoma submitted to surgery were identified among 22 studies selected. Female/male ratio was 1.5 and median age 44 years. Median diameter was 5 cm (range 2 to 10). Most schwannoma were asymptomatic (68.2%) and received an intracapsular excision (64.9%). Postoperative symptoms were reported in 22.6% of patients. Cervical vagal schwannoma is a benign pathology requiring surgical excision, but frequently postoperative complications can affect patients lifelong, so, surgical indications should be based carefully on the balance between risks and benefits