Multi-scale time-resolved electron diffraction: A case study in moiré materials.

Ultrafast-optical-pump - structural-probe measurements, including ultrafast electron and x-ray scattering, provide direct experimental access to the fundamental timescales of atomic motion, and are thus foundational techniques for studying matter out of equilibrium. High-performance detectors are needed in scattering experiments to obtain maximum scientific value from every probe particle. We deploy a hybrid pixel array direct electron detector to perform ultrafast electron diffraction experiments on a WSe2/MoSe2 2D heterobilayer, resolving the weak features of diffuse scattering and moiré superlattice structure without saturating the zero order peak. Enabled by the detector's high frame rate, we show that a chopping technique provides diffraction difference images with signal-to-noise at the shot noise limit. Finally, we demonstrate that a fast detector frame rate coupled with a high repetition rate probe can provide continuous time resolution from femtoseconds to seconds, enabling us to perform a scanning ultrafast electron diffraction experiment that maps thermal transport in WSe2/MoSe2 and resolves distinct diffusion mechanisms in space and time.

A kiloelectron-volt ultrafast electron micro-diffraction apparatus using low emittance semiconductor photocathodes.

We report the design and performance of a time-resolved electron diffraction apparatus capable of producing intense bunches with simultaneously single digit micrometer probe size, long coherence length, and 200 fs rms time resolution. We measure the 5d (peak) beam brightness at the sample location in micro-diffraction mode to be 7 × 10 13 A / m 2 rad 2 . To generate high brightness electron bunches, the system employs high efficiency, low emittance semiconductor photocathodes driven with a wavelength near the photoemission threshold at a repetition rate up to 250 kHz. We characterize spatial, temporal, and reciprocal space resolution of the apparatus. We perform proof-of-principle measurements of ultrafast heating in single crystal Au samples and compare experimental results with simulations that account for the effects of multiple scattering.

CBETA: First Multipass Superconducting Linear Accelerator with Energy Recovery.

Energy recovery has been achieved in a multipass linear accelerator, demonstrating a technology for more compact particle accelerators operating at higher currents and reduced energy consumption. Energy delivered to the beam during the first four passes through the accelerating structure was recovered during four subsequent decelerating passes. High-energy efficiency was achieved by the use of superconducting accelerating cavities and permanent magnets. The fixed-field alternating-gradient optical system used for the return loop successfully transported electron bunches of 42, 78, 114, and 150 MeV in a common vacuum chamber. This new kind of accelerator, an eight-pass energy recovery linac, has the potential to accelerate much higher current than existing linear accelerators while maintaining small beam dimensions and consuming much less energy per electron.

Hormonal and metabolic aspects of acne vulgaris in women with polycystic ovary syndrome.

OBJECTIVE: Acne vulgaris in women can indicate a systemic disease, such as polycystic ovary syndrome (PCOS), which is associated with hormonal and metabolic disorders. The aim of this study was to investigate the influence of hormonal and metabolic disorders on acne vulgaris in women with PCOS. PATIENTS AND METHODS: The study included 110 women with PCOS. Women were divided according to their androstenedione concentration: within reference range (n=66) or higher (n=44). All patients were between 17-36 years old. Acne was graded according to the US FDA scale for a five-category global system (acne global severity scale). Hirsutism was defined using a modified Ferriman-Gallwey method. Fasting plasma glucose, insulin, luteinizing hormone, follicle-stimulating hormone, 17α-hydroxyprogesterone, 17-beta-estradiol, sex hormone-binding globulin and androgen (androstenedione, total testosterone, free testosterone, dehydroepiandrosterone sulfate) were assessed, as were prolactin and cortisol concentrations. Thyrotropin and free thyroxine concentrations were also measured. The free androgen index (FAI) and homeostatic model assessment-insulin resistance (HOMA-IR) index were calculated. RESULTS: The average age and rating on the hirsutism scale were similar in both analyzed groups. A higher percentage of severe acne was observed in the group of women with an androstenedione concentration within reference range than in the group with the higher concentration. Meanwhile, the severity of acne in the group of PCOS women with the higher androstenedione concentration was correlated with higher concentrations of total testosterone, free testosterone, dehydroepiandrosterone sulfate, and cortisol. Increased glucose concentration was also proportional to the severity of acne. We did not observe a statistically significant correlation between the severity of acne and the androstenedione concentration. In the group of PCOS women as a whole, the severity of acne was correlated only with higher dehydroepiandrosterone sulfate concentration; other androgens did not affect the severity. CONCLUSIONS: The acne global severity scale in PCOS women is associated with higher concentrations of total testosterone, free testosterone, dehydroepiandrosterone sulfate, and FAI value. Higher concentrations of androstenedione did not affect acne severity.

Fast readout algorithm for cylindrical beam position monitors providing good accuracy for particle bunches with large offsets.

A simple, analytically correct algorithm is developed for calculating "pencil" relativistic beam coordinates using the signals from an ideal cylindrical particle beam position monitor (BPM) with four pickup electrodes (PUEs) of infinitesimal widths. The algorithm is then applied to simulations of realistic BPMs with finite width PUEs. Surprisingly small deviations are found. Simple empirically determined correction terms reduce the deviations even further. The algorithm is then tested with simulations for non-relativistic beams. As an example of the data acquisition speed advantage, a Field Programmable Gate Array-based BPM readout implementation of the new algorithm has been developed and characterized. Finally, the algorithm is tested with BPM data from the Cornell Preinjector.

Resonant third harmonic generation of KrF laser in Ar gas.

Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence.

Generation of 8 nJ pulses from a dissipative-soliton fiber laser with a nonlinear optical loop mirror.

Theoretical and experimental investigations of the behavior of normal-dispersion fiber lasers with nonlinear optical loop mirrors are presented. The use of a loop mirror causes the laser to generate relatively long, flat-topped pulses. The pulse energy can be high, but the pulse duration is limited to greater than 300 fs. Experimentally, 8 nJ pulses that can be dechirped to 340 fs duration are obtained. The laser is a step toward an all-fiber, environmentally stable design.

Far-infrared absorption of PbSe nanorods.

Measurements of the far-infrared absorption spectra of PbSe nanocrystals and nanorods are presented. As the aspect ratio of the nanorods increases, the Fröhlich sphere resonance splits into two peaks. We analyze this splitting with a classical electrostatic model, which is based on the dielectric function of bulk PbSe but without any free-carrier contribution. Good agreement between the measured and calculated spectra indicates that resonances in the local field factors underlie the measured spectra.

Control of electron transfer from lead-salt nanocrystals to TiO2.

The roles of solvent reorganization energy and electronic coupling strength on the transfer of photoexcited electrons from PbS nanocrystals to TiO(2) nanoparticles are investigated. We find that the electron transfer depends only weakly on the solvent, in contrast to the strong dependence in the nanocrystal-molecule system. This is ascribed to the larger size of the acceptor in this system, and is accounted for by Marcus theory. The electronic coupling of the PbS and TiO(2) is varied by changing the length, aliphatic and aromatic structure, and anchor groups of the linker molecules. Shorter linker molecules consistently lead to faster electron transfer. Surprisingly, linker molecules of the same length but distinct chemical structures yield similar electron transfer rates. In contrast, the electron transfer rate can vary dramatically with different anchor groups.

Role of solvent dielectric properties on charge transfer from PbS nanocrystals to molecules.

Transfer of photoexcited charge from PbS nanocrystals to ligand molecules is investigated in different solvents. We find that the charge transfer rate increases dramatically with solvent dielectric constant. This trend is accounted for by a modified Marcus theory that incorporates only static dielectric effects. The choice of solvent allows significant control of the charge transfer process. As an important example, we find that PbS nanocrystals dispersed in water exhibit charge transfer rates 1000 times higher than the same nanocrystals in organic solvent. Rapid charge extraction will be important to efficient nanocrystal-based photovoltaic and photodetector devices.

Demonstration of a neonlike argon soft-x-ray laser with a picosecond-laser-irradiated gas puff target.

We demonstrate a neonlike argon-ion x-ray laser, using a short-pulse laser-irradiated gas puff target. The gas puff target was formed by pulsed injection of gas from a high-pressure solenoid valve through a nozzle in the form of a narrow slit and irradiated with a combination of long, 600-ps and short, 6-ps high-power laser pulses with a total of 10 J of energy in a traveling-wave excitation scheme. Lasing was observed on the 3p (1)S(0)?3s (1)P(1) transition at 46.9 nm and the 3d (1)P(1)?3p (1)P(1) transition at 45.1 nm. A gain of 11 cm(-1) was measured on these transitions for targets up to 0.9 cm long.

[Actinobacteriosis of paranasal sinuses]. / Aktynobakterioza zatok przynosowych.

On the base the review of literature and own case the authors presents diagnostic difficulties and therapy of paranasal sinuses actinobacteriosis. Actinobacteriosis of sinuses is very rare case and diagnostic analysis based on mycologic and histopathologic investigations. In our case sinuses actinobacteriosis orbital abscess complication has been noted. Antibiotic therapy and surgical treatment have been used in this case.

Self-photopumped neonlike x-ray laser.

We propose a new x-ray laser mechanism that uses radiation from the strongest 3d ? 2p Ne-like resonance line in an optically thick plasma to radiatively drive population from the Ne-like ground state to the 3d state, which then lases to two 3p states. Collisional mixing of the 3p states with nearby 3s and 3d states depopulates the lower laser states. Modeling is presented for this mechanism in Ne-like Ar, and in experiments we observe one potential 3d ? 3p lasing transition at 45.1 nm in Ne-like Ar.

[Late metastasis of clear cell renal cancer to the tonsillar palate]. / Pózny przerzut raka jasnokomórkowego nerki do migdalka podniebiennego.

The authors present a rare case of metastases from clear cell renal cancer to palate tonsillar and temporal bone. In their opinion, by patients with this dis periodical ENT-examination it's necessary. Clinical manifestations, surgical management and therapeutic results are described.

[Determination of blood glucose values with glucostix]. / Oznaczanie stezenia glukozy we krwi za pomoca testu paskowego Glucostix.

The study involved 214 patients of both sexes, including those treated at the Institute of Oncology in Gliwice and children treated for diabetes mellitus at the Diabetic++ Out-Patient Clinic in Gliwice. Blood glucose was assayed with GLUKOZA EO kit manufactured by POCh and strip test Glucostix (visually and with reflectance meter Glucometer II Ames). In case of blood glucose assays with strip tests a deviation of +/- 25% of the determined value was considered as a difference which does not affect diagnostic value. Blood glucose concentration determined visually with Glucostix test is similar or lower than that found in the laboratory. Moreover, the use of reflectance meter does not improve diagnostic value of an assay.