Strain-induced Landau levels of Majorana fermions in an anisotropically interacting Kitaev model on a honeycomb lattice

The energy structure of an anisotropically interacting Kitaev model on a honeycomb lattice under triaxial strain is investigated. A numerical calculation shows that quantized states appear in the low-energy region, even when the anisotropy of the interaction is rather strong. Their energies are proportional to the square root of the quantum number and the quantized state at zero energy appears only on one sublattice. These findings indicate the emergence of the strain-induced Landau levels of Majorana fermions, which is also confirmed by an analytical calculation. These Landau levels are stable, when the direction of triaxial strain is slightly changed from the bond direction.Comment: 10 pages, 7 figures; published version. Effects of the direction of triaxial strain are adde

New function of aldoxime dehydratase: Redox catalysis and the formation of an expected product

In general, hemoproteins are capable of catalyzing redox reactions. Aldoxime dehydratase (OxdA), which is a unique heme-containing enzyme, catalyzes the dehydration of aldoximes to the corresponding nitriles. Its reaction is a rare example of heme directly activating an organic substrate, unlike the utilization of H2O2 or O2 as a mediator of catalysis by other heme-containing enzymes. While it is unknown whether OxdA catalyzes redox reactions or not, we here for the first time detected catalase activity (which is one of the redox activities) of wild-type OxdA, OxdA(WT). Furthermore, we constructed a His320 → Asp mutant of OxdA [OxdA(H320D)], and found it exhibits catalase activity. Determination of the kinetic parameters of OxdA(WT) and OxdA(H320D) revealed that their Km values for H2O2 were similar to each other, but the kcat value of OxdA(H320D) was 30 times higher than that of OxdA(WT). Next, we examined another redox activity and found it was the peroxidase activity of OxdAs. While both OxdA(WT) and OxdA(H320D) showed the activity, the activity of OxdA(H320D) was dozens of times higher than that of OxdA(WT). These findings demonstrated that the H320D mutation enhances the peroxidase activity of OxdA. OxdAs (WT and H320D) were found to catalyze another redox reaction, a peroxygenase reaction. During this reaction of OxdA(H320D) with 1-methoxynaphthalene as a substrate, surprisingly, the reaction mixture changed to a color different from that with OxdA(WT), which was due to the known product, Russig’s blue. We purified and identified the new product as 1-methoxy-2-naphthalenol, which has never been reported as a product of the peroxygenase reaction, to the best of our knowledge. These findings indicated that the H320D mutation not only enhanced redox activities, but also significantly altered the hydroxylation site of the substrate

Upgrade of Online Storage and Express-Reconstruction System for the Belle II experiment

The backend of the Belle II data acquisition system consists of a high-level trigger system, online storage, and an express-reconstruction system for online data processing. The high-level trigger system was updated to use the ZeroMQ networking library from the old ring buffer and TCP/IP socket, and the new system is successfully operated. However, the online storage and express-reconstruction system use the old type of data transportation. For future maintainability, we expand the same ZeroMQ library-based system to the online storage and express-reconstruction system. At the same time, we introduce two more updates in the backend system. First, online side raw data output becomes compressed ROOT format which is the official format of the Belle II data. The update helps to reduce the bandwidth of the online to offline data transfer and offline-side computing resource usage for data format conversion and compression. Second, high-level trigger output-based event selection is included in the online storage. The event selection allows more statistics of data quality monitoring from the express-reconstruction system. In the presentation, we show the description and test result of the upgrade before applying it to the beam operation and data taking

Improved HLT Framework for Belle II Experiment

The original Belle II HLT framework was formally upgraded replacing the old IPC based ring buffer with the ZeroMQ data transport to overcome the unexpected IPC locking problem. The new framework has been working stably in the beam run so far, but it lacks the capability to recover the processing fault without stopping the on-going data taking. In addition, the compatibility with the offline framework (basf2) was lost which was maintained in the original. In order to solve these, an improved core processing framework is developed based on original basf2, while keeping the existing ZeroMQ data transport between the servers unchanged. A new core framework zmq-basf2 is developed with a lock-free 1-to-N and N-to-1 data transport using the ZeroMQ IPC socket so that it keeps a 100% compatibility with the original ring-buffer based framework. When a processing fault occurs, the affected faulty event is salvaged from the input buffer and sent directly to the output using the ZeroMQ broadcast. The terminated process is automatically restarted without stopping data taking. This contribution describes the detail of the improved Belle II HLT framework with the result of the performance test in the real Belle II DAQ data flow

Studies on conjugation of Spirogyra using monoclonal culture

We succeeded in inducing conjugation of Spirogyracastanacea by incubating algal filaments on agar plate. Conjugation could be induced using clone culture. The scalariform conjugation was generally observed, while lateral conjugation was rarely. When two filaments formed scalariform conjugation, all cells of one filament behaved as male and those of other filament did as female. Very rarely, however, zygospores were formed in both of pair filaments. The surface of conjugation tube was stained with fluorescently labeled-lectins, such as Bandeiraea (Griffonia) simplicifolia lectin (BSL-I) and jacalin. BSL-I strongly stained the conjugation tubes, while weakly did the cell surface of female gamete first and then that of male gamete. Jacalin stained mainly the conjugation tubes. Addition of jacalin inhibited the formation of papilla, suggesting some important role of jacalin-binding material at the initial step of formation of the conjugation tubes

EGFR T790M Mutation as a Possible Target for Immunotherapy; Identification of HLA-A*0201-Restricted T Cell Epitopes Derived from the EGFR T790M Mutation

Treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, has achieved high clinical response rates in patients with non–small cell lung cancers (NSCLCs). However, over time, most tumors develop acquired resistance to EGFR-TKIs, which is associated with the secondary EGFR T790M resistance mutation in about half the cases. Currently there are no effective treatment options for patients with this resistance mutation. Here we identified two novel HLA-A*0201 (A2)-restricted T cell epitopes containing the mutated methionine residue of the EGFR T790M mutation, T790M-5 (MQLMPFGCLL) and T790M-7 (LIMQLMPFGCL), as potential targets for EGFR-TKI-resistant patients. When peripheral blood cells were repeatedly stimulated in vitro with these two peptides and assessed by antigen-specific IFN-γ secretion, T cell lines responsive to T790M-5 and T790M-7 were established in 5 of 6 (83%) and 3 of 6 (50%) healthy donors, respectively. Additionally, the T790M-5- and T790M-7-specific T cell lines displayed an MHC class I-restricted reactivity against NSCLC cell lines expressing both HLA-A2 and the T790M mutation. Interestingly, the NSCLC patients with antigen-specific T cell responses to these epitopes showed a significantly less frequency of EGFR-T790M mutation than those without them [1 of 7 (14%) vs 9 of 15 (60%); chi-squared test, p = 0.0449], indicating the negative correlation between the immune responses to the EGFR-T790M-derived epitopes and the presence of EGFR-T790M mutation in NSCLC patients. This finding could possibly be explained by the hypothesis that immune responses to the mutated neo-antigens derived from T790M might prevent the emergence of tumor cell variants with the T790M resistance mutation in NSCLC patients during EGFR-TKI treatment. Together, our results suggest that the identified T cell epitopes might provide a novel immunotherapeutic approach for prevention and/or treatment of EGFR-TKI resistance with the secondary EGFR T790M resistance mutation in NSCLC patients