Measurements of single-molecule electromechanical properties based on atomic force microscopy fixed-junction technique.

A hybrid technique combining atomic force microscopy and the fixed-junction technique is developed to simultaneously probe the electrical and mechanical characteristics of a single-molecule junction.

Definitive intensity modulated proton re-irradiation for lung cancer in the immunotherapy era.

Introduction: As immunotherapy has improved distant metastasis-free survival (DMFS) in Non-Small Cell Lung Cancer (NSCLC), isolated locoregional recurrences have increased. However, management of locoregional recurrences can be challenging. We report our institutional experience with definitive intent re-irradiation using Intensity Modulated Proton Therapy (IMPT).

Shift Pose: A Lightweight Transformer-like Neural Network for Human Pose Estimation.

High-performing, real-time pose detection and tracking in real-time will enable computers to develop a finer-grained and more natural understanding of human behavior. However, the implementation of real-time human pose estimation remains a challenge. On the one hand, the performance of semantic keypoint tracking in live video footage requires high computational resources and large parameters, which limiting the accuracy of pose estimation.

Deep learning for detection and segmentation of artefact and disease instances in gastrointestinal endoscopy.

The Endoscopy Computer Vision Challenge (EndoCV) is a crowd-sourcing initiative to address eminent problems in developing reliable computer aided detection and diagnosis endoscopy systems and suggest a pathway for clinical translation of technologies. Whilst endoscopy is a widely used diagnostic and treatment tool for hollow-organs, there are several core challenges often faced by endoscopists, mainly: 1) presence of multi-class artefacts that hinder their visual interpretation, and 2) difficulty in identifying subtle precancerous precursors and cancer abnormalities. Artefacts often affect the robustness of deep learning methods applied to the gastrointestinal tract organs as they can be confused with tissue of interest.

Initial Validation of Proton Dose Calculations on SPR Images from DECT in Treatment Planning System.

Purpose: To investigate and quantify the potential benefits associated with the use of stopping-power-ratio (SPR) images created from dual-energy computed tomography (DECT) images for proton dose calculation in a clinical proton treatment planning system (TPS).

Materials And Methods: The DECT and single-energy computed tomography (SECT) scans obtained for 26 plastic tissue surrogate plugs were placed individually in a tissue-equivalent plastic phantom. Relative-electron density (ρ) and effective atomic number ( ) images were reconstructed from the DECT scans and used to create an SPR image set for each plug.

Hybrid Molecular-Junction Mapping Technique for Simultaneous Measurements of Single-Molecule Electronic Conductance and Its Corresponding Binding Geometry in a Tunneling Junction.

Improving the techniques for single-molecule conductance measurements is important for the progress of molecular electronics. In this report, a novel technique, which is named molecular-junction mapping (MJM) technique, is demonstrated to be able to simultaneously measure the electronic conductance of single molecules and their corresponding conformations in an electrode gap. Measured conductances of a few model molecules yield a much narrower distribution as compared with the results obtained using conventional break-junction technique, indicating that better defined metal-molecule contacts can be achieved using this new technique.

Spectroscopic Compton imaging of prompt gamma emission at the MeV energy range.

This work explores a novel tomographic approach to PGAA that is both quantitative and spatially resolved, adapted from a clinical "proton beam range finder" in which MeV gamma rays are imaged by coincidence measurements of Compton scattered gamma rays with multi-detector arrays. We performed preliminary measurements using a Compton camera made with CdZnTe detector arrays on a series of test samples with high-energy (> 1 MeV) gamma emission lines. 3D image reconstructions were performed on the 2.

Single-molecule conductance investigation of BDT derivatives: an additional pattern found to induce through-space channels beyond π-π stacking.

The through-space conductance of individual molecules is supposed to improve the macroscopic carrier movement, but the most widely acclaimed through-space conductance channel just existed in sufficiently close π-π stacked benzene rings. As a breakthrough to this primary cognition, additional conducting channels were confirmed to exist in non-strict face-to-face aligned thiophenes or phenyl-thiophene in BDT derivatives for the first time.

Determination of proton stopping power ratio with dual-energy CT in 3D-printed tissue/air cavity surrogates.

Purpose: To study the accuracy with which proton stopping power ratio (SPR) can be determined with dual-energy computed tomography (DECT) for small structures and bone-tissue-air interfaces like those found in the head or in the neck.

Methods: Hollow cylindrical polylactic acid (PLA) plugs (3 cm diameter, 5 cm height) were 3D printed containing either one or three septa with thicknesses t  = 0.8, 1.

Role of Gene Polymorphisms/Haplotypes and Plasma Level of TGF-β1 in Susceptibility to In-Stent Restenosis Following Coronary Implantation of Bare Metal Stent in Chinese Han Patients.

Transforming growth factor (TGF)-β1 has been implicated in the pathogenesis of restenosis. However, the role of TGF-β1 polymorphisms in development of in-stent restenosis (ISR) after coronary bare metal stent (BMS) implantation in Chinese Han population has not been reported to date. The aim of this study was to explore the association between TGF-β1 gene polymorphisms (-509C/T and 869T/C) and its plasma level in Chinese Han patients with BMS-ISR.

Super-resolution imaging in a multiple layer EPID.

A new portal imager consisting of four vertically stacked conventional electronic portal imaging device (EPID) layers has been constructed in pursuit of improved detective quantum efficiency (DQE). We hypothesize that super-resolution (SR) imaging can also be achieved in such a system by shifting each layer laterally by half a pixel relative to the layer above. Super-resolution imaging will improve resolution and contrast-to-noise ratio (CNR) in megavoltage (MV) planar and cone beam computed tomography (MV-CBCT) applications.

Technical Note: Combination of multiple EPID imager layers improves image quality and tracking performance of low contrast-to-noise objects.

Purpose: We hypothesized that combining multiple amorphous silicon flat panel layers increases photon detection efficiency in an electronic portal imaging device (EPID), improving image quality and tracking accuracy of low-contrast targets during radiotherapy.

Methods: The prototype imager evaluated in this study contained four individually programmable layers each with a copper converter layer, Gd O S scintillator, and active-matrix flat panel imager (AMFPI). The imager was placed on a Varian TrueBeam linac and a Las Vegas phantom programmed with sinusoidal motion (peak-to-peak amplitude = 20 mm, period = 3.

Multi-institutional MicroCT image comparison of image-guided small animal irradiators.

To recommend imaging protocols and establish tolerance levels for microCT image quality assurance (QA) performed on conformal image-guided small animal irradiators. A fully automated QA software SAPA (small animal phantom analyzer) for image analysis of the commercial Shelley micro-CT MCTP 610 phantom was developed, in which quantitative analyses of CT number linearity, signal-to-noise ratio (SNR), uniformity and noise, geometric accuracy, spatial resolution by means of modulation transfer function (MTF), and CT contrast were performed. Phantom microCT scans from eleven institutions acquired with four image-guided small animal irradiator units (including the commercial PXi X-RAD SmART and Xstrahl SARRP systems) with varying parameters used for routine small animal imaging were analyzed.

Design of Automatic Extraction Algorithm of Knowledge Points for MOOCs.

In recent years, Massive Open Online Courses (MOOCs) are very popular among college students and have a powerful impact on academic institutions. In the MOOCs environment, knowledge discovery and knowledge sharing are very important, which currently are often achieved by ontology techniques. In building ontology, automatic extraction technology is crucial.

Temporal signal stability of KCl:Eu(2+) storage phosphor dosimeters.

Purpose: Current KCl:Eu(2+) prototype dosimeters require a wait time of 12 h between irradiation and dosimetric readout. Although irradiating the dosimeters in the evening and reading on the following day works well in the clinical schedule, reducing the wait time to few hours is desirable. The purposes of this work are to determine the origin of the unstable charge-storage centers and to determine if these centers respond to optical or thermal excitation prior to dosimetric readout.

Zinc-induced oxidative damage, antioxidant enzyme response and proline metabolism in roots and leaves of wheat plants.

The purpose of this study was to evaluate antioxidative responses and proline metabolism in roots and leaves of wheat seedlings after treatment with different zinc (Zn) concentrations (0, 0.5, 1 and 3mM) for 6 days. A notable reduction in Zn content was observed in 0.

Clinical evaluation of a commercial orthopedic metal artifact reduction tool for CT simulations in radiation therapy.

Purpose: Severe artifacts in kilovoltage-CT simulation images caused by large metallic implants can significantly degrade the conspicuity and apparent CT Hounsfield number of targets and anatomic structures, jeopardize the confidence of anatomical segmentation, and introduce inaccuracies into the radiation therapy treatment planning process. This study evaluated the performance of the first commercial orthopedic metal artifact reduction function (O-MAR) for radiation therapy, and investigated its clinical applications in treatment planning.

Methods: Both phantom and clinical data were used for the evaluation.

Responses of seedling growth and antioxidant activity to excess iron and copper in Triticum aestivum L.

The purpose of this study was to analyze phytotoxicity mechanism involved in root growth and to compare physiological changes in the leaves of wheat seedlings exposed to short term iron (Fe) and copper (Cu) stresses (0, 100, 300 and 500μM). All applied Fe or Cu concentrations reduced root and shoot lengths, but seed germination was inhibited by Cu only at 500μM. Analyses using fluorescent dye 2',7'-dichlorodihydrofluorescein diacetate indicated enhanced H(2)O(2) levels in seedling roots under Fe and Cu treatments.

Radiation hardness of the storage phosphor europium doped potassium chloride for radiation therapy dosimetry.

Purpose: An important property of a reusable dosimeter is its radiation hardness, that is, its ability to retain its dosimetric merits after irradiation. The radiation hardness of europium doped potassium chloride (KC1:Eu2+), a storage phosphor material recently proposed for radiation therapy dosimetry, is examined in this study.

Methods: Pellet-style KCl:Eu2+ dosimeters, 6 mm in diameter, and 1 mm thick, were fabricated in-house for this study.

Localized nanoscopic surface measurements of nickel-modified mica for single-molecule DNA sequence sampling.

Cleaved, cation-derivatized Muscovite mica is utilized extensively in atomic force microscopy (AFM) imaging because of its flatness over large areas (millimeter cleavage planes with local root-mean-square roughness < 0.3 nm), ease of preparation, and ability to adsorb charged biomolecules such as DNA (work by Hansma and Laney, Guthold et al., and McMaster et al.

Precision enhancement of MALDI-TOF MS using high resolution peak detection and label-free alignment.

We have developed an automated procedure for aligning peaks in multiple TOF spectra that eliminates common timing errors and small variations in spectrometer output. Our method incorporates high-resolution peak detection, re-binning, and robust linear data fitting in the time domain. This procedure aligns label-free (uncalibrated) peaks to minimize the variation in each peak's location from one spectrum to the next, while maintaining a high number of degrees of freedom.

Enhancement of sensitivity and resolution of surface-enhanced laser desorption/ionization time-of-flight mass spectrometric records for serum peptides using time-series analysis techniques.

Background: Measurement of peptide/protein concentrations in biological samples for biomarker discovery commonly uses high-sensitivity mass spectrometers with a surface-processing procedure to concentrate the important peptides. These time-of-flight (TOF) instruments typically have low mass resolution and considerable electronic noise associated with their detectors. The net result is unnecessary overlapping of peaks, apparent mass jitter, and difficulty in distinguishing mass peaks from background noise.