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For the past several decades, we have been able to directly probe the motion of atoms that is associated with chemical transformations and which occurs on the femtosecond ([10.sup.-15]-s) timescale. However, studying the inner workings of atoms and molecules on the electronic timescale (1-4) has become possible only with the recent development of isolated attosecond ([10.sup.-15]-s) laser pulses (5). Such pulses have been used to investigate atomic photoexcitation and photoionization (6,7) and electron dynamics in solids (8), and in molecules could help explore the prompt charge redistribution and localization that accompany photoexcitation processes. In recent work, the dissociative ionization of [H.sub.2] and [D.sub.2] was monitored on femtosecond timescales (9) and controlled using few-cycle near-infrared laser pulses (10). Here we report a molecular attosecond pump--probe experiment based on that work: [H.sub.2] and [D.sub.2] are dissociatively ionized by a sequence comprising an isolated attosecond ultraviolet pulse and an intense few-cycle infrared pulse, and a localization of the electronic charge distribution within the molecule is measured that depends--with attosecond time resolution--on the delay between the pump and probe pulses. The localization occurs by means of two mechanisms, where the infrared laser influences the photoionization or the dissociation of the molecular ion. In the first case, charge localization arises from quantum mechanical interference involving autoionizing states and the laser-altered wavefunction of the departing electron. In the second case, charge localization arises owing to laser-driven population transfer between different electronic states of the molecular ion. These results establish attosecond pump-probe strategies as a powerful tool for investigating the complex molecular dynamics that result from the coupling between electronic and nuclear motions beyond the usual Born--Oppenheimer approximation., Following the successful development of isolated attosecond laser pulses less than a decade ago (5), their use in studying atomic photoexcitation and photoionization (6,7) and electron dynamics in solids (8) [...]

This paper presents results of numerical investigations carried out to explore the benefit of end wall boundary layer removal from critical regions of highly loaded axial compressor blade rows. At the loading level of modern aero engine compressors, the performance is primarily determined by three-dimensional (3D) flow phenomena occurring in the end wall regions. Three-dimensional Navier--Stokes simulations were conducted on both a rotor and a stator test case in order to evaluate the basic effects and the practical value of bleeding air from specific locations at the casing end wall. The results of the numerical survey demonstrated substantial benefits of relatively small bleed rates to the local flow field and to the performance of the two blade rows. On the rotor, the boundary layer fluid was removed from the main flow path through an axisymmetric slot in the casing over the rotor tip. This proved to give some control over the tip leakage vortex flow and the associated loss generation. On the stator, the boundary layer fluid was taken from the flow path through a single bleed hole within the passage. Two alternative off-take configurations were evaluated, revealing a large impact of the bleed hole shape and the location on the cross-passage flow and the suction side corner separation. On both blade rows investigated, rotor and stator, the boundary layer removal resulted in a reduction of the local reverse flow, blockage, and losses in the respective near-casing region. This paper gives insight into changes occurring in the 3D passage flow field near the casing and summarizes the effects on the radial matching and pitchwise-averaged performance parameters, namely loss and deviation of the rotor and stator when suction is active. Primary focus is put on the aerodynamics in the blade rows in the main flow path; details of the internal flow structure within the bleed off-take cavities/ports are not discussed here. [DOI: 10.1115/1.2749297]

The in-situ identification of the isotope causing a radiation alarm at a border crossing is essential for a quick resolution of the case. Commonly, hand-held radioisotope identification devices (RIDs) are used to address this task. Although a number of such devices are commercially available, there is still a gap between the requirements of the users and what is actually available. Two components are essential for the optimal performance of such devices: i) The quality of the raw data--the gamma spectra, and ii) isotope identification software matching the specifics of a certain gamma detector. In this paper, we investigate new spectral gamma detectors for potential use in hand-held radioisotope identification devices. The standard NaI detector is compared with new scintillation and room temperature semiconductor detectors. The following spectral gamma detectors were included into the study: NaI(TI), La[Cl.sub.3](Ce), [sup.6]LiI(Eu), CdW[O.sup.4], hemispheric and coplanar CdZnTe detectors. In the paper basic spectrometric properties are measured and compared in view of their use in RIDs.

An analysis of the shock boundary-layer interaction in a laminar boundary layer and in a fully turbulent layer reveals a significant difference between the laminar and the transition-fixed flow. The piezo receiver suitably determines shock-boundary inferences and transitions. Schlieren photography, Laser-2- Focus anemometry, and pressure measurements indicate that the shock is always curved in the upstream direction during a free transition. At the same Mach number, the shock is present downstream for a free transition. Piezofoil arrays and piezofoil receivers are discussed.

Study Question: When should cystic fibrosis transmembrane conductance regulator (CFTR) mutation analysis be recommended in infertile men based on andrological findings?Summary Answer: CFTR mutation analysis is recommended in all men with unexplained azoospermia in the presence of normal gonadotropin levels.What Is Known Already: While 80-97% of men with congenital bilateral absence of the vas deferens (CBAVD) are thought to carry CFTR mutations, there is uncertainty about the spectrum of clinical and andrological abnormalities in infertile men with bilallelic CFTR mutations. This information is relevant for evidence-based recommendations to couples requesting assisted reproduction.Study Design, Size, Duration: We studied the andrological findings of patients with two CFTR mutations who were examined in one of the cooperating fertility centres in Germany and Austria. In the period of January till July 2019, the completed and anonymized data sheets of 78 adult male patients were returned to and analysed by the project leader at the Institute of Human Genetics in Innsbruck, Austria.Participants/materials, Setting, Methods: Minimum study entry criteria were the presence of two (biallelic) CFTR mutations and results of at least one semen analysis. Andrological assessments were undertaken by standardized data sheets and compared with normal reference values. Seventy-one patients were eligible for the study (n = 30, 42% from Germany, n = 26, 37% from Austria, n = 15, 21% other nations).Main Results and the Role Of Chance: Gonadotropin levels (FSH, LH) were normal, 22% of patients had reduced testosterone values. Mean right testis volume was 23.38 ml (SD 8.77), mean left testis volume was 22.59 ml (SD 8.68) and thereby statistically increased compared to normal (P < 0.01). although the means remained in the reference range of 12-25 ml. Semen analysis revealed azoospermia in 70 of 71 (99%) patients and severe oligozoospermia <0.1 × 106/ml in one patient. Four semen parameters, i.e. ejaculate volume, pH, α-glucosidase and fructose values, were significantly reduced (P < 0.01). Only 18% of patients had a palpatory and sonographically diagnosed CBAVD, while in 31% the diagnosis of CBAVD was uncertain, in 12% patients, the vas deferens was present but hypoplastic, and in 39% the vas deferens was normally present bilaterally. Seminal vesicles were not detectable in 37% and only unilaterally present in 37% of patients. Apart from total testes volume, clinical findings were similar in patients with two confirmed pathogenic CFTR mutations (Group I) compared with patients who carried one pathogenic mutation and one CFTR variant of unknown significance (Group II).Limitations, Reasons For Caution: We could not formally confirm the in trans position of genetic variants in most patients as no family members were available for segregation studies. Nonetheless, considering that most mutations in our study have been previously described without other rare variants in cis, and in view of the compatible andrological phenotype, it is reasonable to assume that the biallelic genotypes are correct.Wider Implications Of the Findings: Our study reveals that CFTR mutation analysis has a broader indication than just the absence of the vas deferens. We recommend to completely sequence the CFTR gene if there is a suspicion of obstructive azoospermia, and to extend this analysis to all patients with unexplained azoospermia in the presence of normal gonadotropin levels.Study Funding/competing Interest(s): German Research Foundation Clinical Research Unit 'Male Germ Cells: from Genes to Function' (DFG CRU326, grants to F.T.). There are no conflicts of interest to declare.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]