Attosecond electron-spin dynamics in Xe 4d photoionization

The photoionization of xenon atoms in the 70-100 eV range reveals several fascinating physical phenomena such as a giant resonance induced by the dynamic rearrangement of the electron cloud after photon absorption, an anomalous branching ratio between intermediate Xe$^+$ states separated by the spin-orbit interaction and multiple Auger decay processes. These phenomena have been studied in the past, using in particular synchrotron radiation, but without access to real-time dynamics. Here, we study the dynamics of Xe 4d photoionization on its natural time scale combining attosecond interferometry and coincidence spectroscopy. A time-frequency analysis of the involved transitions allows us to identify two interfering ionization mechanisms: the broad giant dipole resonance with a fast decay time less than 50 as and a narrow resonance at threshold induced by spin-flip transitions, with much longer decay times of several hundred as. Our results provide new insight into the complex electron-spin dynamics of photo-induced phenomena

Automatic multi‐organ segmentation in dual‐energy CT (DECT) with dedicated 3D fully convolutional DECT networks

Purpose Dual‐energy computed tomography (DECT) has shown great potential in many clinical applications. By incorporating the information from two different energy spectra, DECT provides higher contrast and reveals more material differences of tissues compared to conventional single‐energy CT (SECT). Recent research shows that automatic multi‐organ segmentation of DECT data can improve DECT clinical applications. However, most segmentation methods are designed for SECT, while DECT has been significantly less pronounced in research. Therefore, a novel approach is required that is able to take full advantage of the extra information provided by DECT. Methods In the scope of this work, we proposed four three‐dimensional (3D) fully convolutional neural network algorithms for the automatic segmentation of DECT data. We incorporated the extra energy information differently and embedded the fusion of information in each of the network architectures. Results Quantitative evaluation using 45 thorax/abdomen DECT datasets acquired with a clinical dual‐source CT system was investigated. The segmentation of six thoracic and abdominal organs (left and right lungs, liver, spleen, and left and right kidneys) were evaluated using a fivefold cross‐validation strategy. In all of the tests, we achieved the best average Dice coefficients of 98% for the right lung, 98% for the left lung, 96% for the liver, 92% for the spleen, 95% for the right kidney, 93% for the left kidney, respectively. The network architectures exploit dual‐energy spectra and outperform deep learning for SECT. Conclusions The results of the cross‐validation show that our methods are feasible and promising. Successful tests on special clinical cases reveal that our methods have high adaptability in the practical application

Ultra-stable and versatile high-energy resolution setup for attosecond photoelectron spectroscopy

Attosecond photoelectron spectroscopy is often performed with interferometric experimental setups that require outstanding stability. We demonstrate and characterize in detail an actively stabilized, versatile, high spectral resolution attosecond beamline. The active-stabilization system can remain ultra-stable for several hours with an RMS stability of 13 as and a total pump-probe delay scanning range of \sim 400 fs. A tunable femtosecond laser source to drive high-order harmonic generation allows for precisely addressing atomic and molecular resonances. Furthermore, the interferometer includes a spectral shaper in 4f-geometry in the probe arm as well as a tunable bandpass filter in the pump arm, which offer additional high flexibility in terms of tunability as well as narrowband or polychromatic probe pulses. We show that spectral phase measurements of photoelectron wavepackets with the rainbow RABBIT technique (reconstruction of attosecond beating by two photon transitions) with narrowband probe pulses can significantly improve the photoelectron energy resolution. In this setup, the temporal-spectral resolution of photoelectron spectroscopy can reach a new level of accuracy and precision

Probing electronic decoherence with high-resolution attosecond photoelectron interferometry

Quantum coherence plays a fundamental role in the study and control of ultrafast dynamics in matter. In the case of photoionization, entanglement of the photoelectron with the ion is a well known source of decoherence when only one of the particles is measured. Here we investigate decoherence due to entanglement of the radial and angular degrees of freedom of the photoelectron. We study two-photon ionization via the 2s2p autoionizing state in He using high spectral resolution photoelectron interferometry. Combining experiment and theory, we show that the strong dipole coupling of the 2s2p and 2p$^2$ states results in the entanglement of the angular and radial degrees of freedom. This translates, in angle integrated measurements, into a dynamic loss of coherence during autoionization

Taking the pulse of COVID-19: A spatiotemporal perspective

The sudden outbreak of the Coronavirus disease (COVID-19) swept across the world in early 2020, triggering the lockdowns of several billion people across many countries, including China, Spain, India, the U.K., Italy, France, Germany, and most states of the U.S. The transmission of the virus accelerated rapidly with the most confirmed cases in the U.S., and New York City became an epicenter of the pandemic by the end of March. In response to this national and global emergency, the NSF Spatiotemporal Innovation Center brought together a taskforce of international researchers and assembled implemented strategies to rapidly respond to this crisis, for supporting research, saving lives, and protecting the health of global citizens. This perspective paper presents our collective view on the global health emergency and our effort in collecting, analyzing, and sharing relevant data on global policy and government responses, geospatial indicators of the outbreak and evolving forecasts; in developing research capabilities and mitigation measures with global scientists, promoting collaborative research on outbreak dynamics, and reflecting on the dynamic responses from human societies.Comment: 27 pages, 18 figures. International Journal of Digital Earth (2020

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Attosekund elektron-spinndynamik i Xe 4d fotojonisering

We study photoionization time delays in Xe in the 70-100 eV range by combining attosecond interferometry with coincidence spectroscopy. Supported by calculations using the relativistic random phase approximation, we identify two interfering ionization processes: the giant dipole resonance due to collective effects in 4d to continuum f excitation with a fast decay time of a few tens of attoseconds and a narrow resonance at threshold induced by spin-flip transitions, with much longer decay time of several hundreds attoseconds. Our results provide new insight into the complex electron-spin dynamics of photo-induced phenomena. The dataset includes the recorded electron time of flight (seqxx.csv) and electron kinetic energy (seqxxe.csv) for each laser shot. Scan01, 03, 04, 06, 07 is RABBIT scan in Xenon and Scan 02, 05 is RABBIT scan in Neon.Vi studerar tidsfördröjningar i fotojonisation av Xe i 70-100 eV-område genom att kombinera attosekundinterferometri med koincidensspektroskopi. Med hjälp av beräkningar som använder den relativistiska random phase-approximationen, identifierar vi två interfererande jonisationsprocesser: den ”giant dipole” resonansen på grund av kollektiva effekter i 4d till kontinuum f excitation med en snabb sönderfallstid på några tiotals attosekunder och en smal resonans vid tröskel inducerad av spin-flip-övergångar, med mycket längre sönderfallstid på flera hundra attosekunder. Våra resultat ger ny inblick i den komplexa elektronspinndynamiken i fotoinducerade fenomen. Datasetet innehåller data om 'recorded electron time of flight' (seqxx.csv) och om 'electron kinetic energy' (seqxxe.csv). Mer information finns i dokumentationsfilen

Undersökning av elektronisk dekoherens med högupplöst attosekund fotoelektroninterferometri

We investigate the photoionization of helium atoms by attosecond pulse trains generated via high-order harmonic generation in neon gas. In the frequency domain these attosecond pulse trains correspond to a comb of odd harmonics. The wavelength of the infrared field used for high harmonic generation is chosen so that the 39th harmonic is resonant with the 2s2p resonance in helium situated at 60.147 eV. The attosecond pulse trains are overlapped spatially and temporally with a delayed infrared probe pulse with 10 nm bandwidth and a central wavelength of 800nm. Both pulses are focused on an effusive helium gas jet using a toroidal mirror. The resulting photoelectron spectrum is measured using a 2-meter long magnetic bottle electron spectrometer. The experiments consist in measuring the photoelectron spectrum as a function of the delay between the attosecond pulse train and the infrared probe pulse. The photoelectron spectra exhibit small photoelectron peaks (sidebands) originating from the interference of two photon transitions. These peaks oscillate as a function of the delay between the attosecond pulse train and the infrared field at twice the angular frequency of the probe pulse. We extract the amplitude and phase of the sideband oscillations adjacent to the resonant harmonic. We observe a different amplitude and phase variation in the two sidebands that we interprete as signature of decoherence in the upper harmonic due to coupling to the 2p2 state. The data is acquired using a 2m-long magnetic bottle electron spectrometer. An acceleration voltage of 2V is applied on the permanent magnet and the gas needle and a retarding potential of 34V is applied at the entrance of the flight tube. The design of the MBES is based on the following publication: J. H. Eland et al., Phys. Rev. Lett. 90, 053003 (2003). The experiments consist in measuring time-of-flight spectra as a function of the delay between the attosecond pulse train and the IR probe field. spectrogram.txt is a matrix (41x5001), where each row corresponds to the time of flight spectrum of the photoelectron for a given delay. The values in this matrix correspond to the number of electrons detected for a given delay (rows) and time-of-flight (columns). delay.txt is a vector containing 41 entries corresponding the values of the delay in femtoseconds. TOF.txt is a vector containing 5001 entries corresponding to the values of the electron time of flight in nanoseconds.Vi undersöker fotojonisation av heliumatomer med attosekundspulståg som genereras via övertonsgenerering i neongas. I frekvensdomänen motsvaras attosekundspulståget av en frekvenskam med udda övertoner. Våglängden på det infraröda probfältet som används för övertonsgenering är vald så att den 39:e övertonen är resonant med 2s2p-resonansen i helium belägen vid 60,147 eV. Attosekundpulståget överlappas spatialt och temporärt med en fördröjd infraröd probpuls med en bandbredd på 10 nm och en central våglängd på 800 nm. Båda pulserna fokuseras med en toroidspegel på en helium gasjet. Det resulterande fotoelektronspektrumet mäts med en 2 meter lång magnetisk flaskelektronspektrometer. Experimenten går ut på att mäta fotoelektronspektrat som en funktion av fördröjningen mellan attosekundspulståget och den infraröda probpulsen. Fotoelektronspektrat uppvisar små fotoelektrontoppar (sidband) som härrör från interferensen av två fotonövergångar. Dessa toppar oscillerar som en funktion av fördröjningen mellan attosekundenpulståget och det infraröda probfältet med två gånger vinkelfrekvensen för probpulsen. Vi extraherar amplituden och fasen för sidbandsoscillationen vid resonansövertonen. Vi observerar olika amplitud och fasvariation i de två sidbanden som vi tolkar som en signatur för dekoherens i den övre övertonen på grund av kopplingen till 2p2-tillståndet. Vänligen se engelska katalogsidan för mer information

Functional Mechanism of MicroRNA-25-3p in Hilar Cholangiocarcinoma Cell Proliferation and Migration Through Regulation of Dual Specificity Phosphatase 5

Objective Hilar cholangiocarcinoma (HCCA) is a highly aggressive biliary tract tumor. microRNAs (miRs) exert dual actions in various cancers. This paper seeks to expound on the functional mechanisms of miR-25-3p/dual specificity phosphatase 5 (DUSP5) in HCCA cell proliferation and migration. Methods HCCA-related data were downloaded from GEO database to screen out differentially-expressed genes. The potential target miR (miR-25-3p) and its expression in HCCA were analyzed on Starbase. The binding relation between miR-25-3p and DUSP5 was confirmed by dual-luciferase assay. Levels of miR-25-3p and DUSP5 in FRH-0201 cells and HIBEpics were determined by RT-qPCR and Western blot. miR-25-3p and DUSP5 levels were intervened with to explore their effects on FRH-0201 cells. The apoptosis, proliferation, migration, and invasion of FRH-0201 cells were evaluated by TUNEL, CCK8, scratch healing, and Transwell assays. Flow cytometry was conducted to assess FRH-0201 cell cycle. Levels of cell cycle-related proteins were determined by Western blot. Results DUSP5 was weakly-expressed and miR-25-3p was highly-expressed in HCCA samples and cells. miR-25-3p targeted DUSP5. miR-25-3p suppressed FRH-0201 cell apoptosis and increased cell proliferation, migration, and invasion. DUSP5 overexpression partially abrogated miR-25-3p overexpression-exerted effects on FRH-0201 cells. miR-25-3p stimulated G1/S phase transition of FRH-0201 cells by targeting DUSP5. Conclusion miR-25-3p regulated HCCA cell cycle and facilitated cell proliferation and migration by targeting DUSP5