Accurate control of tape tension and velocity will be required in advanced tape drives, as tape thickness is reduced and track density is increased towards target tape capacities of 100 TB and ...beyond. In this paper, a novel method is introduced for the feedback control of the tape transport in tape drives without tension transducers. The method relies on estimating tape tension variations from the difference of the measured lateral positions of servo read elements on adjacent servo bands. Furthermore, a technique for the suppression of periodic tape tension disturbances, which are caused by reel eccentricities and other once-around effects, is developed and presented. The technique uses a time-varying narrow-band bi-quad filter with variable center frequency to suppress the slowly time-varying disturbances. To avoid the noise enhancement that would occur when the disturbance frequency moves outside of the loop bandwidth, the filter parameters are determined by H∞-norm minimization. Using the proposed tape transport system, we experimentally demonstrate a reduction in the standard deviation of the tension of about 40% and a reduction in the standard deviation of the velocity of about 23% with respect to state-of-the-art tape drives.
Recently, the increase of track density has been shown to be one of the most effective methods to increase the areal bit density and thus the cartridge capacity of future magnetic tape data storage ...systems. Increasing the track density poses stringent positioning requirements to the tape track-following control system. In this work, we investigate four novel timing-based servo patterns, and the impact of their geometrical properties, i.e. azimuthal angle and subframe length, on the position estimation resolution, the system delay and track-following performance. First, the resolution of the patterns versus reader width is assessed by analyzing the noise floor in the power spectrum of the lateral position estimation. This methodology is used to determine the optimal reader width for each pattern. Second, the system delay for each of the new patterns is identified by measuring the frequency response of the track-following actuator. An analytical model of the delay is derived and verified with experimental data. Finally, the impact of resolution and delay on the track-following performance is investigated. The best track-following performance, characterized by a standard deviation of the position-error signal of 4.2nm, was achieved using a pattern with a 36°azimuthal angle. The performance could be further improved down to 4.0nm by time averaging the position estimates.
In biologically inspired spiking neural networks (SNNs) neurons communicate by short pulses, called spikes. SNNs have the potential to be more power efficient than artificial neural networks (ANNs), ...thanks to the fewer computational steps required by the spike transmission and processing, as compared to the multiply-and-accumulate (MAC) operations with wide bit-vectors usually adopted in ANNs. We present the design of two types of SNNs with integrate-and-fire dynamics and single-spike per neuron operation, where neural communication is based on synchronous time-to-first-spike (sTTFS) and time-to-first-spike (TTFS) encoding schemes. In the considered time-encoded SNNs, the information is carried by the timing of the spikes with respect to a reference time. In 7nm CMOS technology both designs are synthesized as VHDL-based random-logic-macros (RLMs) and compared to an equivalent ANN design in terms of power consumption, latency and silicon area, using the Iris data set for inference. A cost function expressed as a product of energy consumption and silicon area is introduced to compare the three network designs. With respect to this cost function, it turns out that the SNN-TTFS implemented for the considered classification task outperforms the ANN used as baseline model.
The recording performance of a new magnetic tape based on ultra-fine, perpendicularly-oriented BaFe particles was investigated. Specifically, using a low lateral tape motion demonstration platform, a ...new servo pattern written on the advanced perpendicularly oriented BaFe medium, a new low friction head technology, a novel synchronous servo channel design, and advanced servo control concepts, we were able to demonstrate a record closed-loop track-follow performance with a 23.4 nm standard deviation of position-error signal, roughly one order of magnitude better than in current tape products. In addition, using read back waveforms captured on the same advanced perpendicularly oriented BaFe medium with a 0.2-μm -wide data reader, we demonstrated write/read performance at 518 kbpi using advanced noise-predictive maximum likelihood (NPML) detection schemes. Combining these two results, we estimate that the new medium can support an areal recording density of up to 29.5 Gb/in 2 . This result demonstrates the scalability and extendability of tape technology using low-cost particulate media.
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Background: Immune checkpoint blockade (ICB) therapy has been effective patients with solid tumors. Currently, tumor expression of programmed death-ligand 1 (PD-L1) is clinically ...used as a biomarker of predicted response to ICBs in non-small cell lung cancer (NSCLC). However, across solid tumors, only a subset of patients benefit from ICBs, so there is need to identify other biomarkers to predict response to ICB. We investigated the use of large panel next generation sequencing (NGS) to characterize biomarkers to ICBs across solid tumors. Methods: NGS and PD-L1 immunohistochemistry (IHC) was performed on a series of solid tumors. NGS analysis included detection of single nucleotide polymorphisms (SNPs), insertions and deletions (indels), copy number variation (CNV), and gene-fusions in 435 cancer-related genes, microsatellite instability (MSI), tumor mutational burden (TMB) based on non-synonymous SNPs, and HPV16/18 and EBV viral status. Genomic alterations in previously reported biomarkers of response to ICBs were assessed. Results: 143 solid tumors were analyzed with NGS and PD-L1 IHC. The samples included 80 NSCLC, 15 colorectal carcinoma, 8 cutaneous melanoma, 6 breast carcinoma, and 34 other solid tumors. The mean TMB varied by tumor type, with the highest in melanoma. The frequency of PD-L1 expression was higher in NSCLC and melanoma compared to colorectal carcinoma. The relationship between PD-L1 expression and the other biomarkers varied by tumor type (Table 1). Positive association (+); Negative association (-): No association (None). Conclusions: We characterized biomarkers to ICBs across a range of solid tumors. We found tumor-specific differences in the mean TMB and frequency of PD-L1 expression. We also found tumor-specific differences in the associations between PD-L1 and other potential biomarkers, including KRAS, NRAs, HRAs, BRAF, and EGFR mutation status. We found no correlation between PD-L1 expression and MSI and viral status. NGS is an efficient platform for analysis of biomarkers in solid tumors.Table: see text
The use of multiple sensors for nanopositioning is well motivated in high-density data-storage devices, such as probe-based data storage devices. In these devices, ultra-high positioning accuracies ...are desired over their lifetime in the presence of external disturbances. In addition to meeting the stringent requirements for nanopositioning, the use of multiple sensors lends itself for performing sensor fusion and obtaining reliable estimates of position and velocity. These estimates can be used for the detection of shocks and vibrations and the calibration of sensors. The objective of this work is to provide a comprehensive overview of the problem of nanopositioning using multiple sensors in the context of probe-based data storage. We present the control of a micro-scanner used in a probe-based data-storage device with two sensors, a global thermal position sensor and medium-derived positional information. In one approach, Kalman and H ∞ filtering are employed to perform sensor fusion, and the resulting state estimates in turn serve to design feedback controllers. An alternate approach is to design a multiple-input single-output controller using either the H 2 or H ∞ control paradigm. These controllers are investigated in detail to reveal the underlying structure and the inherent sensor fusion that takes place. Comparisons are made between the two approaches.
Abstract
Introduction: EGFR is a kinase of the HER/ERBB family and an oncogenic driver, especially for NSCLC, HNSCC and CRC. EGFR targeted therapies have been successfully used for treating cancer ...patients harboring activating EGFR mutations. However a main challenge is acquired drug resistance due to mutations or alternative signaling. While developing next generation drugs is a promising strategy, targeting other alternatives is also an attractive therapeutic option. The purpose of our study is to investigate the mutational landscape of the tumors harbored activating EGFR mutations and to pinpoint potential strategies for overcoming acquired drug resistance and for combinational therapies.
Methods: CancerPlex, a NGS large panel test, which includes targeted, full-gene sequencing of over 400 genes, was applied to analyze a cohort of 2294 patient FFPE samples across majority of solid tumor types.
Results: 1, Among 293 (out of 2294, 12.8%) samples harbored EGFR mutations, 86 (86/293, 29.4%) samples harbored actionable EGFR mutations (namely AE group), such as exon 19 deletion and L858R, which includes 84 lung cancer (79 NSCLC), 1 glioblastoma, and 1 urothelial carcinoma. 2, The genes/variants in the AE group are then subjected to further functional analysis and mapped to several pathways/ biological functions. Our results show that the mutational landscape of activating mutant EGFRs covers most main signaling pathways and biological processes with several features: a), Receptors at different classes, including PKHD1, ROS1, and ERBB2, and genes involving in genome and epigenome stabilities, including ARID1A,, KMT2D, and XPC, have the highest mutation rate in the context of activating EGFR mutations. b), PI3K/AKT/mTOR and Ras-Raf-MEK are two main pathways transducing ligand activated EGFR signals. Our results show that the mutant variants in the PI3K-AKT-mTOR pathway are almost 50% more than those in Ras-Raf-MEK pathway, suggesting that activating mutant EGFRs might preferentially rely on effectors in the PI3K pathway, such as PIK3CA and RICTOR, to transduce oncogenic signals. Of note, no KRAS mutation is found in the AE group. c), As expected, mutations are also found in the TP53/apoptosis and Rb/cell cycle pathways with higher variant number in the TP53/apoptosis axis. d) Strikingly, the number of mutant variants in the Wnt/beta-catenin pathway tops that in the PI3K and TP53 pathways. Several recent publications demonstrated that the Wnt/beta-catenin pathway is abnormally activated in NSCLC and may be a main mechanism of the drug resistance. Our finding that the genes in the Wnt/beta-catenin pathway, including APC, AXIN2, RNF43, and BCL9, are mutated to a great extent in the context of activating EGFR mutations supports the notion that targeting the Wnt/beta-catenin pathway, in combination with EGFR targeted therapies, is a promising therapeutic strategy for the treatment and overcoming drug resistance of EGFR-driven tumors.
Citation Format: Jingrui Jiang, Meaghan Russell, Cheryl Eifert, Angeliki Pantazi, Ruobai Sun, Stephen Lyle, Joerg Heyer, Alexei Protopopov. Genomic profiling of the tumors harboring activating epidermal growth factor receptor mutations abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 379. doi:10.1158/1538-7445.AM2017-379
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