836 research outputs found
Quantum Phase Imaging using Spatial Entanglement
Entangled photons have the remarkable ability to be more sensitive to signal
and less sensitive to noise than classical light. Joint photons can sample an
object collectively, resulting in faster phase accumulation and higher spatial
resolution, while common components of noise can be subtracted. Even more, they
can accomplish this while physically separate, due to the nonlocal properties
of quantum mechanics. Indeed, nearly all quantum optics experiments rely on
this separation, using individual point detectors that are scanned to measure
coincidence counts and correlations. Scanning, however, is tedious, time
consuming, and ill-suited for imaging. Moreover, the separation of beam paths
adds complexity to the system while reducing the number of photons available
for sampling, and the multiplicity of detectors does not scale well for greater
numbers of photons and higher orders of entanglement. We bypass all of these
problems here by directly imaging collinear photon pairs with an
electron-multiplying CCD camera. We show explicitly the benefits of quantum
nonlocality by engineering the spatial entanglement of the illuminating photons
and introduce a new method of correlation measurement by converting time-domain
coincidence counting into spatial-domain detection of selected pixels. We show
that classical transport-of-intensity methods are applicable in the quantum
domain and experimentally demonstrate nearly optimal (Heisenberg-limited) phase
measurement for the given quantum illumination. The methods show the power of
direct imaging and hold much potential for more general types of quantum
information processing and control
The effect of inclination on lower extremity inter-joint coordination during treadmill walking
Purpose/Hypothesis: Inclined walking is a challenging daily task in comparison with level walking. It requires specific control from central nervous system and exhibits increases in muscle activities and alternations of joint kinematics in lower extremities. However, the knowledge of the inclination effect on the inter-joint coordination is limited. Previous studies have shown the benefits of investigating the inter-joint coordination in patients with Parkinsonâs disease, low back pain and hemiplegic gait. This study aimed to evaluate such coordination in healthy young adults during inclined walking.
Number of Subjects: 19 healthy young adults (13 females, 6 males; aged 22 â 29 yrs)
Materials/Methods: Subjects walked at their comfortable speeds for 2 minutes in four inclined treadmill walking conditions (0%, 5%, 10%, and 15% grade). Three-dimensional kinematics data were captured at 100 Hz by an eight-camera Qualisys motion capture system. To calculate the inter-joint coordination, the phase portraits were created by plotting the specific segmentâs angular position versus its angular velocity. The trajectories of these phase portraits were converted from Cartesian coordination to polar coordination to get phase angles. These phase angles were used to calculate the continuous relative phase (CRP) dynamics during a gait cycle between two segments which contained the same joint center. A mean absolute value of the ensemble CRP curve values (MARP) was calculated by averaging the absolute values of all points of the entire ensemble curve. Low MARP indicated that two segments approached to in-phase and vice versa. A two-way repeated ANOVA with Bonferroni correction was used to determine the effect of inclination and the effect of segmental combinations (shank-thigh and foot-shank) on MARP.
Results: There was a significant interaction between the effect of inclination and the effect of segmental combinations on MARP (F(3,108) = 85.85, p \u3c 0.001). The MARP of foot-shank combination was lower than that of shank-thigh combination when walking on 0% grade (p \u3c 0.001, approximately 26% less) and on 5% grade (p \u3c 0.001, approximately 28% less). However, the MARP of foot-shank combination was higher than that of shank-thigh combination when walking on 10% grade (p \u3c 0.001, approximately 26% more) and on 15% (p \u3c 0.001, approximately 55% more).
Conclusions: When the grade increased to a certain level, the inter-joint coordination changed to a different pattern during treadmill walking.
Clinical Relevance: Inclined treadmill walking could be used for lower extremity strengthening, gait training, and cardiopulmonary conditioning. The inclination of walking should challenge the patients properly without increased risk. Our study provided a further understanding of inclination effect on gait pattern and could be used as a reference for clinical decision making. This result suggested that the pattern of the inter-joint coordination changed when the grade was between 5% to 10%. Therefore, for population with a higher fall risk, such as older adults, below 5% grade might be recommended
SOFTWARE-AS-A-SERVICE (SAAS) INNOVATION IN THE CONTEXT OF SOFTWARE INDUSTRY: A RESOURCE ORCHESTRATION PERSPECTIVE
Cloud computing brings a paradigm shift in the software industry and changes the business model of software vendors (SV). Software as a service (SaaS), the most popular form of cloud computing, has been recognized as the fundamental change in the delivery, utilization, and management of software. While the transformation to SaaS requires changes within the organization, SVs must actively take action to attract customers to accept the SaaS business model, the so-called pull strategy. Drawing on the resource orchestration view, we propose that the antecedents (i.e., structuring cloud resources, developing service bundling capability, and leveraging cloud ecosystem) are related to the likelihood of an innovative SaaS, which, in turn, is associated with SaaS attractiveness to users. Our proposed research framework provides a guideline for SV to attract and persuade customers to adopt SaaS solutions actively
Flow-Scanning Microfluidic Imaging
The advantages of microfluidics for fast analysis of microscopic suspensions have led to the commercial development of flow cytometers. In this chapter, we propose new microscopy methods that combine controlled motion of micro-organisms in a laminar microfluidic flow, optics, and computation. We propose three new imaging modalities. We first introduce a flow-based version of structured illumination microscopy, where the necessary phase shifts are no longer obtained by controlled displacement of the illumination pattern but by flowing the sample itself. Then, we propose a three-dimensional (3D) deconvolution microscopy method with a microfluidic device for continuous acquisition of gradually defocused images. Finally, we introduce a microfluidic device for phase-space image acquisition, and computational methods for the reconstruction of either phase of intensity, in 3D. The imaging modalities we introduce all retain the benefits of fluid systems for noninvasive bioimaging. The proposed devices can easily be integrated on existing microscopes as a modified microscope slide, or on flow cytometers, and aquatic imagers with minor adjustments. Alternative on-chip implementations are also possible, with lens-free devices, and near-field optical and microfluidic elements directly assembled on the surface of a CCD (Charge-Coupled Device) or CMOS (Complementary metalâoxideâsemiconductor) chip
Mutations in the PKM2 exon-10 region are associated with reduced allostery and increased nuclear translocation.
PKM2 is a key metabolic enzyme central to glucose metabolism and energy expenditure. Multiple stimuli regulate PKM2's activity through allosteric modulation and post-translational modifications. Furthermore, PKM2 can partner with KDM8, an oncogenic demethylase and enter the nucleus to serve as a HIF1α co-activator. Yet, the mechanistic basis of the exon-10 region in allosteric regulation and nuclear translocation remains unclear. Here, we determined the crystal structures and kinetic coupling constants of exon-10 tumor-related mutants (H391Y and R399E), showing altered structural plasticity and reduced allostery. Immunoprecipitation analysis revealed increased interaction with KDM8 for H391Y, R399E, and G415R. We also found a higher degree of HIF1α-mediated transactivation activity, particularly in the presence of KDM8. Furthermore, overexpression of PKM2 mutants significantly elevated cell growth and migration. Together, PKM2 exon-10 mutations lead to structure-allostery alterations and increased nuclear functions mediated by KDM8 in breast cancer cells. Targeting the PKM2-KDM8 complex may provide a potential therapeutic intervention
A Cascaded Approach for ultraly High Performance Lesion Detection and False Positive Removal in Liver CT Scans
Liver cancer has high morbidity and mortality rates in the world. Multi-phase
CT is a main medical imaging modality for detecting/identifying and diagnosing
liver tumors. Automatically detecting and classifying liver lesions in CT
images have the potential to improve the clinical workflow. This task remains
challenging due to liver lesions' large variations in size, appearance, image
contrast, and the complexities of tumor types or subtypes. In this work, we
customize a multi-object labeling tool for multi-phase CT images, which is used
to curate a large-scale dataset containing 1,631 patients with four-phase CT
images, multi-organ masks, and multi-lesion (six major types of liver lesions
confirmed by pathology) masks. We develop a two-stage liver lesion detection
pipeline, where the high-sensitivity detecting algorithms in the first stage
discover as many lesion proposals as possible, and the lesion-reclassification
algorithms in the second stage remove as many false alarms as possible. The
multi-sensitivity lesion detection algorithm maximizes the information
utilization of the individual probability maps of segmentation, and the
lesion-shuffle augmentation effectively explores the texture contrast between
lesions and the liver. Independently tested on 331 patient cases, the proposed
model achieves high sensitivity and specificity for malignancy classification
in the multi-phase contrast-enhanced CT (99.2%, 97.1%, diagnosis setting) and
in the noncontrast CT (97.3%, 95.7%, screening setting)
Characteristics and Trends with Respect to Unintentional Pesticide Poisoning Mortality and Hospitalization in Taiwan, 1999-2008
Conserved charged amino acid residues in the extracellular region of sodium/iodide symporter are critical for iodide transport activity
<p>Abstract</p> <p>Background</p> <p>Sodium/iodide symporter (NIS) mediates the active transport and accumulation of iodide from the blood into the thyroid gland. His-226 located in the extracellular region of NIS has been demonstrated to be critical for iodide transport in our previous study. The conserved charged amino acid residues in the extracellular region of NIS were therefore characterized in this study.</p> <p>Methods</p> <p>Fourteen charged residues (Arg-9, Glu-79, Arg-82, Lys-86, Asp-163, His-226, Arg-228, Asp-233, Asp-237, Arg-239, Arg-241, Asp-311, Asp-322, and Asp-331) were replaced by alanine. Iodide uptake abilities of mutants were evaluated by steady-state and kinetic analysis. The three-dimensional comparative protein structure of NIS was further modeled using sodium/glucose transporter as the reference protein.</p> <p>Results</p> <p>All the NIS mutants were expressed normally in the cells and targeted correctly to the plasma membrane. However, these mutants, except R9A, displayed severe defects on the iodide uptake. Further kinetic analysis revealed that mutations at conserved positively charged amino acid residues in the extracellular region of NIS led to decrease NIS-mediated iodide uptake activity by reducing the maximal rate of iodide transport, while mutations at conserved negatively charged residues led to decrease iodide transport by increasing dissociation between NIS mutants and iodide.</p> <p>Conclusions</p> <p>This is the first report characterizing thoroughly the functional significance of conserved charged amino acid residues in the extracellular region of NIS. Our data suggested that conserved charged amino acid residues, except Arg-9, in the extracellular region of NIS were critical for iodide transport.</p
- âŠ