Amplification Stage Research Articles

Reducing wavelength jitter in white-light seeded femtosecond optical parametric chirped-pulse amplifiers.

White light generation (WLG) in bulk material can be used as a versatile broadband seed source for optical parametric chirped pulse amplification (OPCPA) stages. In this case, it is beneficial to optimize the performance of the WLG seeder in combination with the subsequent OPCPA stage. Here, we characterize how small variations in the drive pulse energy affect the white light seeder performance, in particular the wavelength stability of the amplified OPCPA spectrum. To isolate the influence of drive pulse energy on the OPCPA central wavelength, we introduce a phase-sensitive amplitude measurement and carefully optimize the drive pulse focus position (at the bulk) to minimize the sensitivity to the jitter of the drive pulse energy. With additional active stabilization of the delay between pump and seed pulses in the OPCPA, we achieve a central wavelength jitter of 2 × 10-4. With this performance, our source is an ideal front-end for applications in laser-plasma acceleration or free-electron laser seeding.

Adenosine-5′-Triphosphate (ATP)-Powered Signal-Amplified Probe for Imaging of Fibroblast Activation Protein Associated with Lung Cancer

Fibroblast activation protein (FAP) plays an important role in the progress of lung cancer, but an effective tool has not been reported for revealing the relationship between them. In this work, an adenosine-5-triphosphate (ATP)-powered signal-amplified probe, named ASAP, was prepared using a FAP-sensitive polymer and ATP-binding fluorophore. This probe was employed to determine FAP based upon signal amplification. In the living cells, the activated polymer is destroyed by FAP and the internal fluorophor is released, causing the first stage of signal amplification. Furthermore, the free fluorophor can bind with endogenous ATP to enhance the fluorescence intensity, realizing the second stage of amplification. By virtue of the double amplification, FAP was determined from 0 to 50 ng/mL with a detection limit of 0.26 ng/mL. Moreover, cell imaging showed that the endogenous FAP was successfully imaged in lung carcinoma cells with ASAP, demonstrating the relationship between FAP and lung cancer.

EAFNet: Extraction-amplification-fusion network for tiny cracks detection

Tiny cracks are often overlooked in the inspection process, causing huge economic losses and dangerous accidents. Therefore, tiny cracks should be detected in a timely and accurate manner to eliminate the disease at the initial stage. Inspired by the fact that humans are more likely to capture conspicuous information when observing objects, we propose a novel three-stage Extraction-Amplification-Fusion network (EAFNet). Specifically, in the extraction stage, we utilize an effective backbone network for feature extraction of tiny cracks. In the amplification stage, we design a Tiny Feature Amplification (TFA) module to amplify the extracted features. In the fusion stage, we propose a Two-Branch Fusion (TBF) module to fully fuse the feature maps at different resolutions. To make tiny crack information more ‘conspicuous’, we propose an activation function TinyReLU to enhance the contrast of the tiny cracks with the background. In addition, we construct a Tiny Crack (T-CRACK) dataset with six different backgrounds and a Cross-scale Crack (C-CRACK) dataset. On both datasets, EAFNet achieves an advantage over the existing 8 advanced networks. The two datasets are available at: https://github.com/EAFNet/EAFNet.

Dual structure-switching aptamer-mediated signal amplification cascade for SARS-CoV-2 detection

Since the outbreak of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) at the end of 2019, the spread of the virus has posed a significant threat to public health and the global economy. This work proposed a one-step, dual-structure-switching aptamer-mediated signal amplification cascade for rapid and sensitive detection of the SARS-CoV-2 nucleocapsid protein. This system consisted of two DNA aptamers with structure-switching functionality and fuel DNA, where a cascade of strand hybridization and displacement triggered fluorescence generation and signal amplification. This aptamer-based amplification cascade required neither an amplification stage using enzymes nor pre-processing steps such as washing, viral isolation, and gene extraction. The assay could distinguish SARS-CoV-2 from other respiratory viruses and detect up to 1.0 PFU/assay of SARS-CoV-2 within 30 min at room temperature. In 35 nasopharyngeal clinical samples, the assay accurately assessed 25 positive and 10 negative clinical swab samples, which were confirmed using quantitative polymerase chain reaction. The strategy reported herein can help detect newly emerging pathogens and biomarkers of various diseases in liquid samples. In addition, the developed detection system consisting of only DNA and fluorophores can be widely integrated into liquid biopsy platforms for disease diagnosis.

Sensorless model-based displacement estimator for piezoelectric actuator through a practical three-stage mechanism

Piezoelectric elements (PEMs) are used in a variety of applications. In this paper, we developed a new simple sensorless method for a Piezoelectric Actuator (PEA), which includes piezostack elements and a three-stage amplification mechanism.This research focuses on a piezoelectric actuator that incorporates a three-stage amplification system, where the outcome of one stage serves as the input for the subsequent one. The actuator receives two types of inputs: the voltage applied to the piezoelectric elements and the mechanical load it carries. Its output is defined by the rotation angle observed at the end of the third amplification stage. To indirectly measure the actuator's displacement, a basic external circuit is utilized.The precise movement of these actuators is essential. To circumvent the high costs and limitations associated with highly accurate displacement sensors, there has been a growing interest in sensorless control methods. Certain electrical signals, when measured, can provide an estimation of displacement. However, induced voltage measurements are not effective for piezoelectric stacks. Two more promising measures are the voltage and current of the piezoelectric material.Given that the electrical charge on these actuators closely reflects their displacement with minimal hysteresis across a broad frequency spectrum, it's proposed that displacement can be effectively gauged through current measurements that assess charge.The core contribution of this paper is the introduction and validation, both theoretically and experimentally, of a hybrid algorithm that leverages these two electrical signals to enhance the accuracy of displacement estimates. This was confirmed using a laboratory setup.The primary benefit of this research is the presentation of a straightforward sensorless control algorithm, poised for further exploration within the realm of piezoelectric actuators. The simplicity of both the theoretical model and the sensorless technique facilitates their application across a diverse range of piezoelectric actuators and amplification systems, thereby streamlining the design, modeling, and control strategy development for various actuators.The innovation of this study stems from the application of an uncomplicated sensorless estimation algorithm, coupled with a system-level perspective on piezoelectric actuators. This approach utilizes a simple, adaptable model suitable for a wide array of applications and operational techniques.

Coupling Exponential to Linear Amplification for Endpoint Quantitative Analysis.

Exponential DNA amplification techniques are fundamental in ultrasensitive molecular diagnostics. These systems offer a wide dynamic range, but the quantification requires real-time monitoring of the amplification reaction. Linear amplification schemes, despite their limited sensitivity, can achieve quantitative measurement from a single end-point readout, suitable for low-cost, point-of-care, or massive testing. Reconciling the sensitivity of exponential amplification with the simplicity of end-point readout would thus break through a major design dilemma and open a route to a new generation of massively scalable quantitative bioassays. Here a hybrid nucleic acid-based circuit design is introduced to compute a logarithmic function, therefore providing a wide dynamic range based on a single end-point measurement. CELIA (Coupling Exponential amplification reaction to LInear Amplification) exploits a versatile biochemical circuit architecture to couple a tunable linear amplification stage - optionally embedding an inverter function - downstream of an exponential module in a one-pot format. Applied to the detection of microRNAs, CELIA provides a limit of detection in the femtomolar range and a dynamic range of six decades. This isothermal approach bypasses thermocyclers without compromising sensitivity, thereby opening the way to applications in various diagnostic assays, and providing a simplified, cost-efficient, and high throughput solution for quantitative nucleic acid analysis.

Classification of laser beam profiles using machine learning at the ELI-NP high power laser system

The high power laser system at Extreme Light Infrastructure—Nuclear Physics has demonstrated 10 PW power shot capability. It can also deliver beams with powers of 1 PW and 100 TW in several different experimental areas that carry out dedicated sets of experiments. An array of diagnostics is deployed to characterize the laser beam spatial profiles and to monitor their evolution during the amplification stages. Some of the essential near-field and far-field profiles acquired with CCD cameras are monitored constantly on a large screen television for visual observation and for decision making concerning the control and tuning of the laser beams. Here, we present results on the beam profile classification obtained from datasets with over 14 600 near-field and far-field images acquired during two days of laser operation at 1 PW and 100 TW. We utilize supervised and unsupervised machine learning models based on trained neural networks and an autoencoder. These results constitute an early demonstration of machine learning being used as a tool in the laser system data classification.

Generic qPCR assays for quality control in environmental DNA research

AbstractEnvironmental DNA (eDNA) has been widely used for species surveillance. However, the lack of adequate quality control in many eDNA research projects and applications can lead to false‐negative results, greatly affecting biosecurity surveillance and conservation efforts. Exogenous DNA is routinely added to eDNA samples and used as a positive control, typically after DNA extraction. However, this type of positive control is only able to identify false negatives due to errors at the amplification stage. Therefore, errors in upstream processes, such as sample collection will not be identified by an exogenous control. We designed two independent sets of generic quality control qPCR assays (QCqPCR) targeting abundant endogenous DNA that is obtained during sample collection. Our QCqPCR assays target the chloroplast 16S and 23S ribosomal RNA sequences. In silico analyses indicated these regions were highly conserved among plants, algae and bacteria commonly found in freshwater, marine, or terrestrial environments. These QCqPCR assays were purposely mismatched against the human genome to avoid false positives resulting from human DNA contamination. Both assays remained highly efficient and sensitive under annealing temperatures between 58 and 62°C, allowing them to be multiplexed with most qPCR analyses. We validated our assays by multiplexing with a species‐specific Murray cod (Maccullochella peelii) assay on field‐collected environmental water samples. Potential false‐negative reactions can be identified by the failed or suppressed QCqPCR assay and the negative species‐specific assay. We recommend incorporating either one of the QCqPCR assays in qPCR‐based eDNA analysis to identify potential false negatives and improve the reliability of eDNA surveys.

All fiber single frequency pulsed Yb doped laser source scaling up to 600 uJ at 1 kHz

An all-fiber based high energy single frequency pulsed laser at 1030 nm with fixed repetition rate of 1 kHz was demonstrated. The system adopts a master oscillator power amplifier configuration. In the main amplification stage, we employed a highly doped, very large core diameter of 50 μm YDF fiber as the laser gain media. 670 μJ, 500 ns pulse train was obtained, corresponding to a peak power of 1.34 kW. Such a high-peak-power and high-repetition-rate SF source is well suited for long range coherent imaging, optical remote sensing, and coherent interferometry, etc.

Molecular Identification of Lactic Acid Bacteria from Broiler Chicken Meat

Lactic acid bacteria are bacteria used to ferment food. Molecular identification of isolates of lactic acid bacteria has a high degree of accuracy compared to morphological identification. This study aimed to molecularly identify isolates of lactic acid bacteria from broiler chickens. Molecular identification is carried out in 3 stages, namely: rRNA gene amplification stage, squencing and phylogeny tree. PCR electrophoresis results obtained amplicone results measuring about 1,500 bp. The results of BLAST analysis showed that the gen 16S rRNA sequence of BR 17 lactic acid bacteria isolate had a 97-98% similarity with the genome sequence of the Lactobacillus fermentum strain. Development of phylogenetic tree isolates of single clusters of lactic acid bacteria BR 17 with strains of Lactobacillus fermentum CAU2036, Lactobacillus fermentum JCM 7772, and Lactobacillus fermentum 10-18. The identification results of lactic acid bacteria isolate BR 17 showed Lactobacillus fermentum BR 17.

Signal shapes in multiwire proportional chamber-based TPCs

A large-volume Time Projection Chamber (TPC) is the main tracking and particle identification (PID) detector of the ALICE experiment at the CERN LHC. PID in the TPC is performed via specific energy-loss measurements (dE/dx), which are derived from the average pulse-height distribution of ionization generated by charged-particle tracks traversing the TPC volume. During Runs 1 and 2, until 2018, the gas amplification stage was based on multiwire proportional chambers (MWPC). Signals from the MWPC show characteristic long negative tails after an initial positive peak due to the long ion drift times in the MWPC amplification region. This so-called ion tail can lead to a significant amplitude loss in subsequently measured signals, especially in the high-multiplicity environment of high-energy Pb-Pb collisions, which results in a degradation of the dE/dx resolution. A detailed study of the signal shapes measured with the ALICE TPC with the Ne-CO2 (90-10) and Ar-CO2 (90-10) gas mixtures is presented, and the results are compared with three-dimensional Garfield simulations. The impact of the ion tail on the PID performance is studied employing the ALICE simulation framework and the feasibility of an offline correction procedure to account for the ion tail is demonstrated.

The μ-RWELL in High Energy Physics and beyond

The μ-RWELL, a resistive Micro-Pattern Gaseous Detector with a single amplification stage, is crafted using a copper-clad polyimide foil intricately micro-patterned with a blind hole (well) matrix. This matrix is integrated into the readout Printed Circuit Board, complemented by a thin Diamond-Like-Carbon sputtered resistive film, in order to mitigate the transition from streamer to spark regimes, enabling the attainment of substantial gains (≥104). However, this arrangement diminishes the detector's capacity to withstand high particle fluxes.For low-rate applications, the simplest resistive configuration utilises a single resistive layer with edge grounding. This design, however, exhibits a non-uniform response under elevated particle irradiation. To overcome this behaviour, new current evacuation geometries have been developed. In this work, we examine the efficacy of various high-rate resistive layouts, trialled at the prestigious CERN H8-SpS and PSI πM1 beam testing facilities. These designs are tailored to meet the demanding requisites of detectors operating in the HL-LHC environment, as well as those of future experiments at the next generation colliders, such as the FCC-ee/hh and CepC.

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy.

We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10-8 to (3.6 ± 0.14) × 10-8 nC Gy-1 mCi-1 mm-2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively. The prototype detectors provide an unprecedented sensitivity thanks to its monolithic amplification stage. Future investigation of this technology will include the optimisation of the packaging technique.

Adaptable Dual-Tuned Optically Controlled On-Coil RF Power Amplifier for MRI.

An adaptable optically controlled RF power amplifier (RFPA) is presented for direct implementation on the Magnetic Resonance Imaging (MRI) transmit coil. Operation at 1H and multiple X-nuclei frequencies for 7T MRI was demonstrated through the automated tuning of an effective voltage-modulated inductor located in the gate driver circuit of the FET switches in the different amplification stages. Through this automated tuning the amplifier can be adapted from the control to operate at the selected 1H and X-nuclei frequency in a multinuclear MRI study. Bench and MRI data acquired with the adaptable dual-tuned on-coil RFPA is presented. This technology should allow a simpler, more efficient and versatile implementation of the multinuclear multichannel MRI hardware. Ultimately, to extend the research on MRI detectable nuclei that can provide new insights about healthy and diseased tissue.

A 12-bit 1.5-GS/s Single-Channel Pipelined SAR ADC With a Pipelined Residue Amplification Stage

A 12-bit 1.5-GS/s Single-Channel Pipelined SAR ADC With a Pipelined Residue Amplification Stage

Benchmarking of Sensor Configurations and Measurement Sites for Out-of-the-Lab Photoplethysmography.

Photoplethysmography (PPG) is used for heart-rate monitoring in a variety of contexts and applications due to its versatility and simplicity. These applications, namely studies involving PPG data acquisition during day-to-day activities, require reliable and continuous measurements, which are often performed at the index finger or wrist. However, some PPG sensors are susceptible to saturation, motion artifacts, and discomfort upon their use. In this paper, an off-the-shelf PPG sensor was benchmarked and modified to improve signal saturation. Moreover, this paper explores the feasibility of using an optimized sensor in the lower limb as an alternative measurement site. Data were collected from 28 subjects with ages ranging from 18 to 59 years. To validate the sensors' performance, signal saturation and quality, wave morphology, performance of automatic systolic peak detection, and heart-rate estimation, were compared. For the upper and lower limb locations, the index finger and the first toe were used as reference locations, respectively. Lowering the amplification stage of the PPG sensor resulted in a significant reduction in signal saturation, from 18% to 0.5%. Systolic peak detection at rest using an automatic algorithm showed a sensitivity and precision of 0.99 each. The posterior wrist and upper arm showed pulse wave morphology correlations of 0.93 and 0.92, respectively. For these locations, peak detection sensitivity and precision were 0.95, 0.94 and 0.89, 0.89, respectively. Overall, the adjusted PPG sensors are a good alternative for obtaining high-quality signals at the fingertips, and for new measurement sites, the posterior pulse and the upper arm allow for high-quality signal extraction.

Sub-50 fs, 0.5 W average power Nd-doped fiber amplifier at 920 nm.

We develop an all polarization-maintaining (PM) 920 nm Nd-doped fiber amplifier delivering a train of pulses with ∼0.53 W average power and sub-50 fs duration. The sub-50 fs pulse benefits from the pre-chirping management method that allows for over 60 nm broadening spectrum without pulse breaking in the amplification stage. By virtue of the short pulse duration, the pulse peak power can reach to ∼0.31 MW in spite of the moderate average power. These results represent a key step in developing high-peak-power pulse Nd-doped fiber laser systems at 920 nm, which will find important applications in fields such as biomedical imaging, ultrafast optical spectroscopy, and excitation of quantum-dot single photon sources.

Gaseous argon time projection chamber with electroluminescence enhanced optical readout

Systematic uncertainties in accelerator oscillation neutrino experiments arise from nuclear models describing neutrino-nucleus interactions. To mitigate these uncertainties, we can study neutrino-nuclei interactions with detectors possessing enhanced hadron detection capabilities at energies below the nuclear Fermi level. Gaseous detectors not only lower the particle detection threshold but also enable the investigation of nuclear effects on various nuclei by allowing for changes in the gas composition. This approach provides valuable insights into the modelling of neutrino-nucleus interactions and significantly reduces associated uncertainties. Here, we discuss the design and first operation of a gaseous argon time projection chamber optically read. The detector operates at atmospheric pressure and features a single stage of electron amplification based on a thick GEM. Here, photons are produced with wavelengths in the vacuum ultraviolet regime. In an optical detector, the primary constraint is the light yield. This study explores the possibility of increasing the light by applying a low electric field downstream of the ThGEM. In this region, called the electroluminescence gap, electrons propagate and excite the argon atoms, leading to the subsequent emission of photons. This process occurs without any further electron amplification, and it is demonstrated that the total light yield increases up to three times by applying moderate electric fields of the order of 3 kV/cm. Finally, an indirect method is discussed for determining the photon yield/charge gain of a ThGEM, giving a value of 18.3 photons detected per secondary electron.

SDN control of amplification stages in multi-band optical networks

SDN control of amplification stages in multi-band optical networks

Recurrent Somatic Copy Number Alterations and Their Association with Oncogene Expression Levels in High-Grade Ovarian Serous Carcinoma.

Somatic copy number alterations (SCNAs) are frequently observed in high-grade ovarian serous carcinoma (HGOSC). However, their impact on gene expression levels has not been systematically assessed. In this study, we explored the relationship between recurrent SCNA and gene expression using The Cancer Genome Atlas Pan Cancer dataset (OSC, TCGA, PanCancer Atlas) to identify cancer-related genes in HGOSC. We then investigated any association between highly correlated cancer genes and clinicopathological parameters, including age of diagnosis, disease stage, overall survival (OS), and progression-free survival (PFS). A total of 772 genes with recurrent SCNAs were observed. SCNA and mRNA expression levels were highly correlated for 274 genes; 24 genes were classified as a Tier 1 gene in the Cancer Gene Census in the Catalogue of Somatic Mutations in Cancer (CGC-COSMIC). Of these, 11 Tier 1 genes had highly correlated SCNA and mRNA expression levels: TBL1XR1, PIK3CA, UBR5, EIF3E, RAD21, EXT1, RECQL4, KRAS, PRKACA, BRD4, and TPM4. There was no association between gene amplification and disease stage or PFS. EIF3E, RAD21, and EXT1 were more frequently amplified in younger patients, specifically those under the age of 55 years. Patients with tumors carrying PRKACA, BRD4, or TPM4 amplification were associated with a significantly shorter OS. RECQL4 amplification was more frequent in younger patients, and tumors with this amplification were associated with a significantly better OS.