Position-sensitive detection of ultracold neutrons with an imaging camera and its implications to spectroscopy

Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15 $\mu$m has been achieved, which is equivalent to an UCN energy resolution below 2 pico-electron-volts through the relation $\delta E = m_0g \delta x$. Here, the symbols $\delta E$, $\delta x$, $m_0$ and $g$ are the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This method allows different types of UCN spectroscopy and other applications.Comment: 12 figures, 28 pages, accepted for publication in NIM

Search for neutron dark decay: n → χ + e⁺e⁻

In January, 2018, Fornal and Grinstein proposed that a previously unobserved neutron decay branch to a dark matter particle (χ) could account for the discrepancy in the neutron lifetime observed in two different types of experiments. One of the possible final states discussed includes a single χ along with an e⁺e⁻ pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with ∼ 4π acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). We use the timing information of coincidence events to select candidate dark sector particle decays by applying a timing calibration and selecting events within a physically-forbidden timing region for conventional n → p + e⁻ + ν̅_e decays. The summed kinetic energy (E_(e⁺e⁻)) from such events is reconstructed and used to set limits, as a function of the χ mass, on the branching fraction for this decay channel

timed modeling and verification of bpel processes using time petri nets

Software Engineering Society of Korean; Institute for Information Scientists and Engineers; IEEE Reliability Society; KAIST (Korea Advanced Institute of Science and Technology); Korea Information Promotion Agency; Samsung SDSThe execution time, an important criterion to measure the quality of a BPEL process, can be influenced by some slow external partner services (i.e., some long-running services). Therefore, it is desirable to specify response time of services into the SLAs (service level agreements). In this way, service consumers could verify whether the candidate services satisfy the expected time requirements before they are invoked. However, existing solutions are time-consuming especially when the BPEL process is quite complex (e.g., involving parallel structures and loops) and the number of candidate services is huge. To address this problem, in this paper, we propose a time Petri nets-based verification approach that efficiently verifies time requirements for a BPEL process. This allows service consumers to quickly identify suitable partner services that satisfy the time requirements at service looking up stage. © 2009 IEEE

Small molecular non-fullerene acceptors based on naphthalenediimide and benzoisoquinoline-dione functionalities for efficient bulk-heterojunction devices

Through the conjunction of naphthalenediimide and benzoisoquinoline-dione functionalities, two novel, solution-processable non-fullerene electron acceptors, 2,7-dioctyl-4,9-bis(2-octyl-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-6-yl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (coded as NDI-N1) and 2,7-dioctyl-4,9-bis(5-(2-octyl-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-6-yl)thiophen-2-yl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (coded as NDI-N2), were designed, synthesized, and used as active components for bulk-heterojunction photovoltaic devices. The new chromophores were based on the acceptor-acceptor-acceptor module where naphthalenediimide unit served as the central acceptor flanked by terminal benzoisoquinoline-dione acceptor functionality. The optoelectronic and photovoltaic properties of NDI-N1 and NDI-N2 were directly compared. Solution-processable bulk-heterojunction devices were fabricated using NDI-N1 and NDI-N2 as non-fullerene electron acceptor materials. Studies on the photovoltaic properties revealed that the best poly(3-hexylthiophene) (P3HT): NDI-N2-based device showed an impressive enhanced power conversion efficiency of 4.04%, around 40% increase with respect to the efficiency of the best NDI-N1-based device (2.91%). It is justifiable to mention that the device outcome reported herein provides strong support and incentive for the current research strategy, and that the conjoint use of potential acceptor building blocks, such as naphthalenediimide and benzoisoquinoline-dione, can indeed generate efficient non-fullerene acceptors

Small molecular non-fullerene acceptors based on naphthalenediimide and benzoisoquinoline-dione functionalities for efficient bulk-heterojunction devices

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Herbal Extract from Codonopsis pilosula (Franch.) Nannf. Enhances Cardiogenic Differentiation and Improves the Function of Infarcted Rat Hearts

Background: The roots of Codonopsis pilosula (Franch.) Nannf. have been used in traditional Chinese medicine for treating cardiovascular disease. In the current study, we aimed to discover herbal extracts from C. pilosula that are capable of improving cardiac function of infarcted hearts to develop a potential therapeutic approach. Methods: A mouse embryonic stem (ES) cell-based model with an enhanced green fluorescent protein (eGFP) reporter driven by a cardiomyocyte-specific promoter, the α-myosin heavy chain, was constructed to evaluate the cardiogenic activity of herbal extracts. Then, herbal extracts from C. pilosula with cardiogenic activity based on an increase in eGFP expression during ES cell differentiation were further tested in a rat myocardial infarction model with left anterior descending artery (LAD) ligation. Cardiac function assessments were performed using echocardiography, 1, 3, and 6 weeks post LAD ligation. Results: The herbal extract 417W from C. pilosula was capable of enhancing cardiogenic differentiation in mouse ES cells in vitro. Echocardiography results in the LAD-ligated rat model revealed significant improvements in the infarcted hearts at least 6 weeks after 417W treatment that were determined based on left ventricle fractional shortening (FS), fractional area contraction (FAC), and ejection fraction (EF). Conclusions: The herbal extract 417W can enhance the cardiogenic differentiation of ES cells and improve the cardiac function of infarcted hearts

Cerebral and myocardial mitochondrial injury differ in a rat model of cardiac arrest and cardiopulmonary resuscitation

Brain mitochondria are more sensitive to global ischemia compared to heart mitochondria. Complex I in the electron transport chain (ETC) is sensitive to ischemic injury and is a major control point of the rate of ADP stimulated oxygen consumption. The purpose of this study was to explore whether changes in cerebral and myocardial mitochondria differ after cardiac arrest. Animals were randomized into 4 groups (n = 6): 1) Sham 2) VF 3) VF+CPR 4) ROSC 1hr. Ventricular Fibrillation (VF) was induced through a guide wire advanced from the right jugular vein into the ventricle and untreated for 8 min. Resuscitation was attempted with a 4J defibrillation after 8 min of cardiopulmonary resuscitation (CPR). Brain mitochondria and cardiac mitochondrial subpopulations were isolated. Calcium retention capacity was measured to assess susceptibility to mitochondrial permeability transition pore opening. ADP stimulated oxygen consumption and ETC activity assays were performed. Brain mitochondria are far more sensitive to injury during cardiac arrest and resuscitation compared to cardiac mitochondria. Complex I is highly sensitive to injury in brain mitochondria. With markedly decreased calcium retention capacity, mitochondria contribute to cerebral reperfusion injury. Therapeutic preservation of cerebral mitochondrial activity and mitochondrial function during cardiac arrest may improve post-resuscitation neurologic function