Electromechanical wavelength tuning of double-membrane photonic crystal cavities

We present a method for tuning the resonant wavelength of photonic crystal cavities (PCCs) around 1.55 um. Large tuning of the PCC mode is enabled by electromechanically controlling the separation between two parallel InGaAsP membranes. A fabrication method to avoid sticking between the membranes is discussed. Reversible red/blue shifting of the symmetric/anti-symmetric modes has been observed, which provides clear evidence of the electromechanical tuning, and a maximum shift of 10 nm with < 6 V applied bias has been obtained.Comment: 9 pages, 3 figure

Bayesian Non-Exhaustive Classification A Case Study: Online Name Disambiguation using Temporal Record Streams

The name entity disambiguation task aims to partition the records of multiple real-life persons so that each partition contains records pertaining to a unique person. Most of the existing solutions for this task operate in a batch mode, where all records to be disambiguated are initially available to the algorithm. However, more realistic settings require that the name disambiguation task be performed in an online fashion, in addition to, being able to identify records of new ambiguous entities having no preexisting records. In this work, we propose a Bayesian non-exhaustive classification framework for solving online name disambiguation task. Our proposed method uses a Dirichlet process prior with a Normal * Normal * Inverse Wishart data model which enables identification of new ambiguous entities who have no records in the training data. For online classification, we use one sweep Gibbs sampler which is very efficient and effective. As a case study we consider bibliographic data in a temporal stream format and disambiguate authors by partitioning their papers into homogeneous groups. Our experimental results demonstrate that the proposed method is better than existing methods for performing online name disambiguation task.Comment: to appear in CIKM 201

Multimodel strong coupling of photonic crystal cavities of dissimilar size

A photonic crystal three missing holes nanocavity, having only a few modes, is coupled to a 60 missing holes long multimode cavity, both fabricated in the same InGaAsP membrane. The coupling was studied in detail by the photothermal tuning of the small cavity over about three free spectral ranges of the large cavity. Strong coupling effects, involving at least three large cavity modes simultaneously, were observed from level anticrossing data. The observations are excellently reproduced by a model of coupled Fabry Perot resonator

The interaction between ectomycorrhizal fungi and growth promoting bacteria in plant development from in-vitro to the field

There is currently an array of biotechnological tools which may positively influence plant development and establishment. Symbiosis with ectomycorrhizal fungi is known to improve plant health by increasing nutrient and water uptake and alleviating environmental stresses. Some rhizosphere bacteria are also proven to act as plant stimulating agents, health managers and growth promoters. The use of a combined inoculum using both microorganisms has great potential in forestry. Nevertheless, the interaction between fungi and bacteria is highly specific and bacteria are known not only to enhance fungal growth (mycorrhiza promoting bacteria), but also to strongly inhibit it. It is therefore important to evaluate the compatibility between ectomycorrhizal fungi and bacteria and to determine the impact of such combination in plant development when aiming at the use of optimized microbial inoculum for enhancing plant growth. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with ectomycorrhizal fungi, from in-vitro tests to a nursery stage followed by transplantation to the field. Approximately 5000 seedlings were used in these experiments comprising Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal. The first sampling was made before field transplantation. Results showed that the combined use of fungi-bacteria inoculum significantly influenced plant growth and its effect was different from that of each individual microbial partner, emphasizing the strong interaction between microorganisms

Combining ectomycorrhizal fungi and bacteria: a powerful tool to improve tree performance

Ectomycorrhizal fungi are ubiquitous to forest soils and the symbiosis between these microorganisms and plants roots is known to be essential for tree establishment and development, especially in areas of poor soil. Studies have also shown that some rhizosphere bacteria may act as plant stimulating agents and growth promoters. Additionally, bacteria and fungi strongly interact and therefore the analysis of the triangle plant-fungi-bacteria is a vital approach when aiming at the use of microbial inocula to enhance plant performance. To obtain a synergistic combination between microorganisms, a thorough selection is required since bacteria may strongly inhibit fungal growth, and vice versa, incurring in the risk of failed inoculum. In the present work we investigated the use of a dual inoculation system, consisting of a bacterial strain from the genus Mesorhizobium in combination with selected ectomycorrhizal fungi. In vitro tests were performed to assess the dynamic of co-culturing both microorganisms. The inoculum was applied at nursery stage and saplings were then transplanted into the field. Approximately 5000 seedlings were used in this experiment comprising the following species: Quercus suber, Quercus robur, Quercus rubra, Pinus pinaster and Pinus pinea. Seedlings were grown for 9 months in a commercial forest greenhouse and then transplanted to 4 locations in Portugal: Mindelo, Santo Tirso, Vila do Conde and Proença-a-Nova. Samples were taken at the end of nursery phase and 8 months after transplantation. Biometric and mycorrhizal parameters were analyzed and the persistence of the inoculated strains was evaluated. The presence of selected phytohormones was also determined. Results showed that the combined use of fungi-bacteria inoculum can be more effective than the use of each individual microbial partner. The use of ectomycorrhizal fungi and bacteria has great potential in forestry as a biotechnological tool to produce high performance plants at nursery stage and in the field

Impact of bacterial inoculation of Quercus suber on mycorrhization by Suillus species at early stages of tree development

Portugal accounts for approximately 50% of the world cork production. Quercus suber is the second most abundant tree in Continental Portugal, covering currently 737 thousand hectares and representing 23% of the forest area. This species is of paramount importance to the country both ecologically and economically. As many other forest species, Q. suber forms symbiotic associations with ectomycorrhizal (ECM) fungi with the hyphae acting as fine extensions of the plant root system allowing it to capture water and nutrients in exchange for photosynthetic carbohydrates. The use of bacteria as inoculum also has great potential in forestry, whether through their capability to act as plant growth promoters (PGPB) or/and as mycohhizal helper bacteria (MHB). The latter have a direct impact in promoting fungal symbiosis and could possibly represent the third link in the mycorrhizal partnership. However, the association between all vertices of the triangle (plant-fungi-bacteria) is highly specific and needs to be further explored when aiming at the use of microbial inocula in the tuning of mycorrhization at nursery stage. The aim of this work was to study the impact of inoculating Q. suber with a fungus belonging to the genus Suillus and a bacterial strain belonging to the genus Mesorhizobium, proven to be PGPB in preliminary studies. The experiment was conducted in a forest nursery in Amarante. After 9 months, the impact of inoculating with each microorganism individually was compared to that of the use of the combined inoculum. Biometric parameters were determined (shoot height, primary and secondary root length, shoot and root dry weight) and mycorrhizal parameters were assessed (percentage of ECM colonisation and expansion rate). The presence of selected phytohormones was also determined by HPLC. Overall, inoculated plants had a superior performance than the non-inoculated controls, in the majority of the parameters studied. The use of the combined inoculum was more successful than any other treatment in promoting shoot height and led to the highest concentration of indoleacetic acid (IAA). The results obtained suggest that the use of bacteria in the mycorrhization of Q. suber may positively affect plant in its early stage of development

EGFR and ERBB2 exon 20 insertion/duplication in advanced non–small cell lung cancer: genomic profiling and clinicopathologic features

BackgroundExon 20 (ex20) in-frame insertions or duplications (ins/dup) in epidermal growth factor receptor (EGFR) and its analog erb-b2 receptor tyrosine kinase 2 (ERBB2) are each detected in 1.5% of non–small cell lung cancer (NSCLC). Unlike EGFR p.L858R or ex19 deletions, ex20 ins/dup is associated with de novo resistance to classic EGFR inhibitors, lack of response to immune checkpoint inhibitors, and poor prognosis. US Food and Drug Administration has approved mobocertinib and amivantamab for targeting tumors with this aberration, but the number of comprehensive studies on ex20 ins/dup NSCLC is limited. We identified 18 cases of NSCLCs with EGFR/ERBB2 ex20 ins/dup and correlated the findings with clinical and morphologic information including programed death-ligand 1 (PD-L1) expression.MethodsA total of 536 NSCLC cases tested at our institution between 2014 and 2023 were reviewed. A custom-designed 214-gene next-generation sequencing panel was used for detecting DNA variants, and the FusionPlex CTL panel (ArcherDx) was used for the detection of fusion transcripts from formalin-fixed, paraffin-embedded tissue. Immunohistochemistry (IHC)for PD-L1 was performed using 22C3 or E1L3N clones.ResultsNine EGFR and nine ERBB2 ex20 ins/dup variants were identified from an equal number of men and women, 14 were non- or light smokers, and 15 had stage IV disease. All 18 cases were adenocarcinomas. Seven of the 11 cases with available primary tumors had acinar predominant pattern, two had lepidic predominant pattern, and the remainder had papillary (one case) and mucinous (one case) patterns. Ex20 ins/dup variants were heterogenous in-frame one to four amino acids spanning A767–V774 in EGFR and Y772–P780 in ERBB2 and were clustered in the loop following the C-helix and α C-helix. Twelve cases (67%) had co-existing TP53 variants. Copy number variation in CDK4 amplification was identified in one case. No fusion or microsatellite instability was identified in any case. PD-L1 was positive in two cases, low positive in four cases, and negative in 11 cases.ConclusionsNSCLCs harboring EGFR/ERBB2 ex20 ins/dup are rare and tend to be acinar predominant, negative for PD-L1, more frequent in non- or light smokers, and mutually exclusive with other driver mutations in NSCLC. The correlation of different EGFR/ERBB2 ex20 ins/dup variants and co-existing mutations with response to targeted therapy and the possibility of developing resistant mutations after mobocertinib treatment warrants further investigation

Direct Fabrication of Atomically Defined Pores in MXenes

Controlled fabrication of nanopores in atomically thin two-dimensional material offers the means to create robust membranes needed for ion transport, nanofiltration, and DNA sensing. Techniques for creating nanopores have relied upon either plasma etching or direct irradiation using electrons or ions; however, aberration-corrected scanning transmission electron microscopy (STEM) offers the advantage of combining a highly energetic, sub-angstrom sized electron beam for atomic manipulation along with atomic resolution imaging. Here, we utilize a method for automated nanopore fabrication with real-time atomic visualization to enhance our mechanistic understanding of beam-induced transformations. Additionally, an electron beam simulation technique, Electron-Beam Simulator (E-BeamSim) was developed to observe the atomic movements and interactions resulting from electron beam irradiation. Using the 2D MXene Ti3C2Tx, we explore the influence of temperature on nanopore fabrication by tracking atomic transformation pathways and find that at room temperature, electron beam irradiation induces random displacement of atoms and results in a pileup of titanium atoms at the nanopore edge. This pileup was confirmed and demonstrated in E-BeamSim simulations around the small, milled area in the MXene monolayer. At elevated temperatures, the surface functional groups on MXene are effectively removed, and the mobility of atoms increases, which results in atomic transformations that lead to the selective removal of atoms layer by layer. Through controllable manufacture using e-beam milling fabrication, the production and then characterization of the fabricated defects can be better understood for future work. This work can lead to the development of defect engineering techniques within functionalized MXene layers.Comment: Experimental and simulations on the electron beam interactions with MXene monolayers to form nanopores as a function of temperatur