Mass Sensing for the Advanced Fabrication of Nanomechanical Resonators

We report on a nanomechanical engineering method to monitor matter growth in real time via e-beam electromechanical coupling. This method relies on the exceptional mass sensing capabilities of nanomechanical resonators. Focused electron beam-induced deposition (FEBID) is employed to selectively grow platinum particles at the free end of singly clamped nanotube cantilevers. The electron beam has two functions: it allows both to grow material on the nanotube and to track in real time the deposited mass by probing the noise-driven mechanical resonance of the nanotube. On the one hand, this detection method is highly effective as it can resolve mass deposition with a resolution in the zeptogram range; on the other hand, this method is simple to use and readily available to a wide range of potential users because it can be operated in existing commercial FEBID systems without making any modification. The presented method allows one to engineer hybrid nanomechanical resonators with precisely tailored functionalities. It also appears as a new tool for studying the growth dynamics of ultrathin nanostructures, opening new opportunities for investigating so far out-of-reach physics of FEBID and related methods

Trypacidin, a Spore-Borne Toxin from Aspergillus fumigatus, Is Cytotoxic to Lung Cells

Inhalation of Aspergillus fumigatus conidia can cause severe aspergillosis in immunosuppressed people. A. fumigatus produces a large number of secondary metabolites, some of which are airborne by conidia and whose toxicity to the respiratory tract has not been investigated. We found that spores of A. fumigatus contain five main compounds, tryptoquivaline F, fumiquinazoline C, questin, monomethylsulochrin and trypacidin. Fractionation of culture extracts using RP-HPLC and LC-MS showed that samples containing questin, monomethylsulochrin and trypacidin were toxic to the human A549 lung cell line. These compounds were purified and their structure verified using NMR in order to compare their toxicity against A549 cells. Trypacidin was the most toxic, decreasing cell viability and triggering cell lysis, both effects occurring at an IC50 close to 7 µM. Trypacidin toxicity was also observed in the same concentration range on human bronchial epithelial cells. In the first hour of exposure, trypacidin initiates the intracellular formation of nitric oxide (NO) and hydrogen peroxide (H2O2). This oxidative stress triggers necrotic cell death in the following 24 h. The apoptosis pathway, moreover, was not involved in the cell death process as trypacidin did not induce apoptotic bodies or a decrease in mitochondrial membrane potential. This is the first time that the toxicity of trypacidin to lung cells has been reported

Mass sensing for the advanced fabrication of nanomechanical resonators

We report on a nanomechanical engineering method to monitor matter growth in real time via e-beam electromechanical coupling. This method relies on the exceptional mass sensing capabilities of nanomechanical resonators. Focused electron beam-induced deposition (FEBID) is employed to selectively grow platinum particles at the free end of singly clamped nanotube cantilevers. The electron beam has two functions: it allows both to grow material on the nanotube and to track in real time the deposited mass by probing the noise-driven mechanical resonance of the nanotube. On the one hand, this detection method is highly effective as it can resolve mass deposition with a resolution in the zeptogram range; on the other hand, this method is simple to use and readily available to a wide range of potential users because it can be operated in existing commercial FEBID systems without making any modification. The presented method allows one to engineer hybrid nanomechanical resonators with precisely tailored functionalities. It also appears as a new tool for studying the growth dynamics of ultrathin nanostructures, opening new opportunities for investigating so far out-of-reach physics of FEBID and related methods

Distribution of plasma fatty acids is associated with response to chemotherapy in non-Hodgkin's lymphoma patients

Our recent data have linked plasma phospholipid fatty acid (FA) profile in patients with non-Hodgkin's lymphoma (NHL) with the clinical stage and aggressiveness of the disease. Thus, we proposed that plasma FA status in these patients may influence the effect of chemotherapy. The aim of this work was to assess FA status in NHL patients undergoing chemotherapy in relation to their response to therapy. We analyzed plasma FA profile in 47 newly diagnosed NHL patients before chemotherapy, after 3 cycles and after the end of the planned chemotherapy. Patients were treated according to the hospital protocol: 28 patients with cyclophosphamide, doxorubicin, vincristine and prednisone, 7 with other anthracycline-containing regimens, 4 patients with cyclophosphamide, vincristine and prednisone and 8 with fludarabine-based regimens. Rituximab was added in 22 patients. Ten patients who did not receive all planned chemotherapy due to death or toxicity (non-completers) had significantly lower (p lt 0.05) baseline proportion of palmitoleic, linoleic, eicosapentaenoic and docosahexaenoic acid, as well as n-3 and n-6 FA, than the patients who completed chemotherapy (completers). Furthermore, the completers were divided according to the response to chemotherapy to complete remission (CR), stable disease and progressive disease (PD). Proportion of palmitic acid after the end of chemotherapy was the highest in the PD group, while stearic acid showed the opposite trend. Palmitoleic acid and all n-3 FA (18: 3, 20: 5, 22: 5 and 22: 6) were the highest in the patients in remission and the lowest in PD (p lt 0.001). Linoleic acid decreased and arachidonic acid increased from the CR to the PD group (p lt 0.001). These results suggest that aberrations in plasma FA may influence response to chemotherapy in patients with NHL