Self-Trapping of Slow Electrons in the Energy Domain.

The interaction of light and swift electrons has enabled phase-coherent manipulation and acceleration of electron wave packets. Here, we investigate this interaction in a new regime where low-energy electrons (∼20-200 eV) interact with a phase-matched light field. Our analytical and one-dimensional numerical study shows that slow electrons are subject to strong confinement in the energy domain due to the nonvanishing curvature of the electron dispersion. The spectral trap is tunable and an appropriate choice of light field parameters can reduce the interaction dynamics to only two energy states. The capacity to trap electrons expands the scope of electron beam physics, free-electron quantum optics and quantum simulators.

Lossless Monochromator in an Ultrafast Electron Microscope Using Near-Field THz Radiation.

The ability to form monoenergetic electron beams is vital for high-resolution electron spectroscopy and imaging. Such capabilities are commonly achieved using an electron monochromator, which energy filters a dispersed electron beam, thus reducing the electron flux to yield down to meV energy resolution. This reduction in flux hinders the use of monochromators in many applications, such as ultrafast transmission electron microscopes (UTEMs). Here, we develop and demonstrate a mechanism for electron energy monochromation that does not reduce the flux-a lossless monochromator. The mechanism is based on the interaction of free-electron pulses with single-cycle THz near fields, created by nonlinear conversion of an optical laser pulse near the electron beam path inside a UTEM. Our experiment reduces the electron energy spread by a factor of up to 2.9 without compromising the beam flux. Moreover, as the electron-THz interaction takes place over an extended region of many tens of microns in free space, the realized technique is highly robust-granting uniform monochromation over a wide area, larger than the electron beam diameter. We further demonstrate the wide tunability of our method by monochromating the electron beam at multiple primary electron energies from 60 to 200 keV, studying the effect of various electron and THz parameters on its performance. Our findings have direct applications in the fast-growing field of ultrafast electron microscopy, allowing time- and energy-resolved studies of exciton physics, phononic vibrational resonances, charge transport effects, and optical excitations in the mid IR to the far IR.

Self-Made Sleeve for Chandelier Light Simulation.

PURPOSE: To develop a quick and cost-effective alternative to a chandelier light for vitrectomy. METHODS: The surgical material available in an ophthalmologic operating room was used to create a sleeve for the vitrectomy light probe and tested on 30 consecutive retinal detachment cases for feasibility. RESULTS: A 64 × 5-mm cotton swab stick was cut into the length of the light probe minus the length of the trocar and subsequently pierced by a blunt needle. With this sleeve, the light probe could be safely handled similar to a chandelier light during surgery. CONCLUSION: A sleeve for the light probe can serve as a substitute for a chandelier light during scleral depression in retinal detachment surgery.

Effects of high-intensity interval training on microvascular glycocalyx and associated microRNAs.

High-intensity interval training (HIIT) has been proposed to exert vasculoprotective effects. This study aimed to evaluate whether HIIT affects the microvasculature, including the endothelial glycocalyx barrier, and to identify associated microRNAs (miRNAs). Fifty healthy participants (23.1 ± 3.0 yr) performed a 4-wk 4 × 30-s all-out running HIIT. Sidestream dark-field imaging was performed at baseline and follow-up to detect changes of the sublingual microvasculature including the endothelial glycocalyx. Exercise parameters were determined by continuous running field test and documentation of high-intensity runs. miRNAs potentially associated with glycocalyx thickness were selected by structured literature search and blood samples for miRNA, and lactate measurements were drawn at baseline and follow-up HIIT. At baseline, a correlation between maximal exercise performance capacity and glycocalyx thickness (determined by perfused boundary region) was detected (P = 0.045, r = 0.303). Increased exercise performance at follow-up also correlated with glycocalyx thickness (P = 0.031, r = 0.416), and increased high-intensity sprinting speed was associated with an increased number of perfused vessels (P = 0.0129, r = 0.449). Literature search identified miR-143, -96-5p, and -24, which were upregulated by HIIT already at baseline and showed an association with peak blood lactate levels after sprints (all P < 0.05). Moreover, increased baseline miR-143 levels predicted increased glycocalyx thickness at follow-up (AUCmiR-143 = 0.92, 95% confidence interval, 0.81-1.0, P = 0.0008). Elevated resting miR-126 levels after the intervention were associated with cell-free versican mRNA levels. We conclude that HIIT induces changes in the endothelial glycocalyx of the microvasculature. Associated miRNAs such as miR-143 may represent a tool for monitoring early vasculoprotective adaptations to physical activity. NEW & NOTEWORTHY High-intensity interval training is known to improve health-related fitness in general and in lifestyle-induced chronic diseases. To visualize microvasculature structure and to detect exercise-induced changes, sublingual sidestream dark-field imaging microscopy was used, and circulating miRNAs were measured. This study shows that exercise-induced changes correlate with associated circulating miRNA, which might be useful for monitoring vasculoprotective effects. Furthermore, sidestream dark-field imaging may represent a sensitive tool for the early detection of exercise-induced systemic vascular changes.

Shaping electron-hole trajectories for solid-state high harmonic generation control.

Solid-state high-harmonic generation (HHG) by an intense infra-red (IR) laser field offers a new route to generate coherent attosecond light pulses in the extreme ultraviolet regime. The propagation of the IR driving field in the dense solid medium is accompanied by non-linear processes which shape the generating waveform. In this work, we introduce a monolithic scheme in which we both exploit the non-linear propagation to manipulate a two color driving field, as well as generate high harmonics within a single crystal. We show that the resulting non-commensurate, bi-chromatic, generating field provides precise control over the periodicity of the HHG process. This control enables us to manipulate the spectral positions of the discrete harmonic peaks. Our method advances solid-state HHG spectroscopy, and offers a simple route towards tunable, robust XUV sources.

Robust enhancement of high harmonic generation via attosecond control of ionization.

High-harmonic generation (HHG) is a powerful tool to generate coherent attosecond light pulses in the extreme ultraviolet. However, the low conversion efficiency of HHG at the single atom level poses a significant practical limitation for many applications. Enhancing the efficiency of the process defines one of the primary challenges in the application of HHG as an advanced XUV source. In this work, we demonstrate a new mechanism, which in contrast to current methods, enhances the HHG conversion efficiency purely on a single particle level. We show that using a bichromatic driving field, sub-optical-cycle control and enhancement of the tunnelling ionization rate can be achieved, leading to enhancements in HHG efficiency by up to two orders of magnitude. Our method advances the perspectives of HHG spectroscopy, where isolating the single particle response is an essential component, and offers a simple route toward scalable, robust XUV sources.

Attosecond control of electrons emitted from a nanoscale metal tip.

Attosecond science is based on steering electrons with the electric field of well controlled femtosecond laser pulses. It has led to the generation of extreme-ultraviolet pulses with a duration of less than 100 attoseconds (ref. 3; 1 as = 10(-18) s), to the measurement of intramolecular dynamics (by diffraction of an electron taken from the molecule under scrutiny) and to ultrafast electron holography. All these effects have been observed with atoms or molecules in the gas phase. Electrons liberated from solids by few-cycle laser pulses are also predicted to show a strong light-phase sensitivity, but only very small effects have been observed. Here we report that the spectra of electrons undergoing photoemission from a nanometre-scale tungsten tip show a dependence on the carrier-envelope phase of the laser, with a current modulation of up to 100 per cent. Depending on the carrier-envelope phase, electrons are emitted either from a single sub-500-attosecond interval of the 6-femtosecond laser pulse, or from two such intervals; the latter case leads to spectral interference. We also show that coherent elastic re-scattering of liberated electrons takes place at the metal surface. Owing to field enhancement at the tip, a simple laser oscillator reaches the peak electric field strengths required for attosecond experiments at 100-megahertz repetition rates, rendering complex amplified laser systems dispensable. Practically, this work represents a simple, extremely sensitive carrier-envelope phase sensor, which could be shrunk in volume to about one cubic centimetre. Our results indicate that the attosecond techniques developed with (and for) atoms and molecules can also be used with solids. In particular, we foresee subfemtosecond, subnanometre probing of collective electron dynamics (such as plasmon polaritons) in solid-state systems ranging in scale from mesoscopic solids to clusters and to single protruding atoms.

Two-Color Coherent Control of Femtosecond Above-Threshold Photoemission from a Tungsten Nanotip.

We demonstrate coherent control of multiphoton and above-threshold photoemission from a single solid-state nanoemitter driven by a fundamental and a weak second harmonic laser pulse. Depending on the relative phase of the two pulses, electron emission is modulated with a contrast of the oscillating current signal of up to 94%. Electron spectra reveal that all observed photon orders are affected simultaneously and similarly. We confirm that photoemission takes place within 10 fs. Accompanying simulations indicate that the current modulation with its large contrast results from two interfering quantum pathways leading to electron emission.

Risk of neonatal mortality according to gestational age after elective repeat cesarean delivery.

PURPOSE: Despite the well-known neonatal morbidity risks after elective cesarean deliveries performed before 39 weeks, there are scarce data regarding mortality risks. The objective of this study was to calculate the risk of neonatal mortality after elective repeat cesarean delivery (ERCD) by gestational age. METHODS: The Linked Birth-Infant Death Data Files from the Vital Statistics Data of the Center for Disease Control and Prevention of the U.S. from 2004 to 2008 were analyzed. Only ERCD cases were included. Early death (<7 days), neonatal death (<28 days), and infant death (<1 year) were evaluated. A logistic regression model was used to calculate odds ratios. Cases delivered at 37-41 weeks were studied with 40 weeks as reference. RESULTS: A total of 483,052 cases were included for analysis. The distribution of rates and odds ratios for infant, neonatal and early death was U-shaped with the nadir at 39 weeks. There was a statistically significant increase in early death at 37 compared to 40 weeks' gestation [OR (95 %) CI = 1.929(1.172-3.176)]. No statistical increase was found in any of the other mortality risks. CONCLUSION: There is an increased risk in early death with ERCD performed at 37 weeks. Our study provides evidence of neonatal harm beyond the reported morbidity risks.

Highly Coherent Electron Beam from a Laser-Triggered Tungsten Needle Tip.

We report on a quantitative measurement of the spatial coherence of electrons emitted from a sharp metal needle tip. We investigate the coherence in photoemission triggered by a near-ultraviolet laser with a photon energy of 3.1 eV and compare it to dc-field emission. A carbon nanotube is brought into close proximity to the emitter tip to act as an electrostatic biprism. From the resulting electron matter wave interference fringes, we deduce an upper limit of the effective source radius both in laser-triggered and dc-field emission mode, which quantifies the spatial coherence of the emitted electron beam. We obtain (0.80±0.05) nm in laser-triggered and (0.55±0.02) nm in dc-field emission mode, revealing that the outstanding coherence properties of electron beams from needle tip field emitters are largely maintained in laser-induced emission. In addition, the relative coherence width of 0.36 of the photoemitted electron beam is the largest observed so far. The preservation of electronic coherence during emission as well as ramifications for time-resolved electron imaging techniques are discussed.

Institute of Medicine Guidelines for Appropiate Pregnancy Weight Gain for Obese Women May Be Too High.

OBJECTIVE: To investigate how the 2009 Institute of Medicine (IOM) guidelines for pregnancy weight gain for obese women relate to the longer-term outcome of childhood obesity. STUDY DESIGN: Maternal, neonatal, soioeconomic, and nutritional histories were collected for mothers with children age 2-5 years old. Women in each body mass index (BMI) category were categorized based on under, appropriate (AG), and over weight gain per IOM guidelines and compared with rates of childhood obesity in each category. RESULTS: A total of 502 mother-child pairs were enrolled; 36.4% of women were obese at the start of pregnancy. Obese women who were AG by IOM guidelines were more likely than underweight, normal weight, and overweight women to have obese offspring (29.5% vs. 14.2%, p = 0.04). The BMI percentiles of the offspring of obese AG women were 10 percentile points higher than the 55th percentile of the other groups. CONCLUSION: The 2009 IOM pregnancy weight gain guidelines for obese women may still be too high when considering longer-term outcomes such as childhood obesity. Further studies are needed.

Improved efficiency of bulk heterojunction hybrid solar cells by utilizing CdSe quantum dot-graphene nanocomposites.

We present a significant efficiency enhancement of hybrid bulk heterojunction solar cells by utilizing CdSe quantum dots attached to reduced graphene oxide (rGO) as the electron accepting phase, blended with the PCPDTBT polymer. The quantum dot attachment to rGO was achieved following a self-assembly approach, recently developed, using thiolated reduced graphene oxide (TrGO) to form a TrGO-CdSe nanocomposite. Therefore, we are able to obtain TrGO-CdSe quantum dot/PCPDTBT bulk-heterojunction hybrid solar cells with power conversion efficiencies of up to 4.2%, compared with up to 3% for CdSe quantum dot/PCPDTBT devices. The improvement is mainly due to an increase of the open-circuit voltage from 0.55 V to 0.72 V. We found evidence for a significant change in the heterojunction donor-acceptor blend nanomorphology, observable by a more vertical alignment of the TrGO-quantum dot nanocomposites in the z-direction and a different nanophase separation in the x-y direction compared to the quantum dot only containing device. Moreover, an improved charge extraction and trap state reduction were observed for TrGO containing hybrid solar cells.

Probing of optical near-fields by electron Rescattering on the 1 nm scale.

We present a new method of measuring optical near-fields within ~1 nm of a metal surface based on rescattering of photoemitted electrons. With this method, we precisely measure the field enhancement factor for tungsten and gold nanotips as a function of tip radius. The agreement with Maxwell simulations is very good. Further simulations yield a field enhancement map for all materials, which shows that optical near-fields at nanotips are governed by a geometric effect under most conditions, while plasmon resonances play only a minor role. Last, we consider the implications of our results on quantum mechanical effects near the surface of nanostructures and discuss features of quantum plasmonics.

Protective Effect of Amblyopia on Age-Related Macular Degeneration.

PURPOSE: Our aim was to evaluate whether patients with age-related macular degeneration (AMD) and cooccurrent amblyopia are more likely to have diseases diagnosed on both the ipsilateral and the contralateral side in a large Austrian database. DESIGN: Retrospective cross-sectional study. METHODS: Setting: Institutional practice. PATIENT POPULATION: Medical records of all patients who visited the Department of Ophthalmology of the Medical University of Graz between December 1996 and June 2021 were searched for the co-occurrence of AMD and amblyopia. MAIN OUTCOME MEASURES: Data from patients with AMD diagnosed on 1 eye side were used for further analysis. Spectral-domain optical coherence tomography images were analyzed to confirm the lateral asymmetry of AMD. RESULTS: A total of 327,443 patients were screened for the co-occurrence of AMD and amblyopia. Of them, 8742 patients had AMD diagnosed on 1 eye side and 5051 patients had unilateral amblyopia. In total, 163 patients were found to have AMD diagnosed on 1 side and unilateral amblyopia in combination. Of these, 126 patients had AMD and amblyopia on contralateral sides and 37 had AMD and amblyopia on the ipsilateral side (P < .001). CONCLUSIONS: Less amblyopic patients had AMD diagnosed on the amblyopic eye compared with the nonamblyopic eye. In cases of lateral asymmetry, the nonamblyopic eye is more likely to have the more advanced form of AMD.

Metabolomic analysis for first-trimester Down syndrome prediction.

OBJECTIVE: The objective of the study was to perform first-trimester maternal serum metabolomic analysis and compare the results in aneuploid vs Down syndrome (DS) pregnancies. STUDY DESIGN: This was a case-control study of pregnancies between 11+0 and 13+6 weeks. There were 30 DS cases and 60 controls in which first-trimester maternal serum was analyzed. Nuclear magnetic resonance-based metabolomic analysis was performed for DS prediction. RESULTS: Concentrations of 11 metabolites were significantly different in the serum of DS pregnancies. The combination of 3-hydroxyisovalerate, 3-hydroxybuterate, and maternal age had a 51.9% sensitivity at 1.9% false-positive rate for DS detection. One multimarker algorithm had 70% sensitivity at 1.7% false-positive rate. Novel markers such as 3-hydroxybutyrate, involved in brain growth and myelination, and 2-hydroxybutyrate, involved in the defense against oxidative stress, were found to be abnormal. CONCLUSION: The study reports novel metabolomic markers for the first-trimester prediction of fetal DS. Metabolomics provided insights into the cellular dysfunction in DS.

First-trimester metabolomic detection of late-onset preeclampsia.

OBJECTIVE: We sought to identify first-trimester maternal serum biomarkers for the prediction of late-onset preeclampsia (PE) using metabolomic analysis. STUDY DESIGN: In a case-control study, nuclear magnetic resonance-based metabolomic analysis was performed on first-trimester maternal serum between 11(+0)-13(+6) weeks of gestation. There were 30 cases of late-onset PE, i.e., requiring delivery ≥37 weeks, and 59 unaffected controls. The concentrations of 40 metabolites were compared between the 2 groups. We also compared 30 early-onset cases to the late-onset group. RESULTS: A total of 14 metabolites were significantly elevated and 3 significantly reduced in first-trimester serum of late-onset PE patients. A complex model consisting of multiple metabolites and maternal demographic characteristics had a 76.6% sensitivity at 100% specificity for PE detection. A simplified model using fewer predictors yielded 60% sensitivity at 96.6% specificity. Strong separation of late- vs early-onset PE groups was achieved. CONCLUSION: Significant differences in the first-trimester metabolites were noted in women who went on to developed late-onset PE and between early- and late-onset PE.

Metabolomic analysis for first-trimester trisomy 18 detection.

OBJECTIVE: The purpose of this study was to determine whether nuclear magnetic resonance-based metabolomic markers in first-trimester maternal serum can detect fetuses with trisomy 18. STUDY DESIGN: This was a study of pregnancies between 11 weeks and 13 weeks 6 days' gestation. We analyzed 30 cases of trisomy 18 and a total of 114 euploid cases. Nuclear magnetic resonance-based metabolomic analysis was performed. A further analysis was performed that compared 30 cases with trisomy 18 and 30 trisomy 21 (T21) cases. RESULTS: Metabolomic markers were sensitive for trisomy 18 detection. A combination of 2-hydroxybutyrate, glycerol and maternal age had a 73.3% sensitivity and 96.6% specificity for trisomy 18 detection, with an area under the receiver operating curve: 0.92 (P < .001). Other metabolite markers, which include trimethylamine, were sensitive for distinguishing trisomy 18 from T21 cases. CONCLUSION: This is the first report of prenatal trisomy 18 detection that has been based on metabolomic analysis. Preliminary results suggest that such markers are sensitive not only for the detection of fetal trisomy 18 but also for distinguishing this aneuploidy from T21.

Chemical bonding and magnetic exchange in two-dimensional [M(TCNE)(NCMe)2]X (M = Fe, Mn; X = FeCl4, SbF6) magnets: a pressure study.

Pressure-dependent X-ray diffraction studies reveal the bulk modulus and compression anisotropy of the 2D magnet [Mn(TCNE)(NCMe)(2)]SbF(6). The Raman response of this and the similar [Fe(TCNE)(NCMe)(2)]FeCl(4) layered magnet, shows that the evolution of the a(g) ν(C=C) frequency correlates well with the magnetic exchange and T(c) variations of these materials under pressure. There is a significantly more complex correlation between the a(g) ν(C≡N) frequency and T(c) despite the fact that some unpaired π* electron density (~0.125 e) is localized on each of TCNE nitrile N≡C group. The shortening of the M-NC bond with pressure (<0.5 GPa) does not result in a T(c) increase, which suggests a more complex bond length magnetic exchange relationship.

Pulmonary aspergillosis: therapeutic management and prognostic factors from 16 years of monocenter experience.

Twenty three patients of the University Hospital Bonn were reviewed following surgical procedures for pulmonary aspergilloma, including the choice of antifungal therapy, diagnostic findings, decision-making in treatment, and treatment outcomes of the past 16 years. We used pathological records to identify aspergilloma patients. A review of patients' records and follow-up phone calls to patients, families, or general practitioners were done. Data collected from 1995 to 2011 included patients with aspergilloma (n = 15), multiple aspergillomas (n = 2) and chronic necrotizing pulmonary aspergillosis (n = 6). Classification and diagnosis were based on pathological records. The decision to use systemic antimycotic therapy was based on perioperative findings suspecting parenchymal involvement of the fungal infection. Seventeen patients received systemic antimycotic chemotherapy. Compared with the use of Amphotericin B, newer drugs such as voriconazol, caspofungin, or posaconazol showed no better result in the morbidity and mortality of the patients. Postoperative complications requiring extended therapy and/or prolonged ICU stay (>48 h) were seen in 12 (52.2%) patients. During follow-up there were ten deaths; one death (4.4%) from aspergillus-associated sepsis, nine deaths from patients' underlying diseases (n = 4 within <3 months, n = 6 within >3 months of follow-up). In conclusion, in our cohort, immunocompromised patients with no documented preexisting lung-cavities were most likely to develop pulmonary aspergilloma. Postoperative morbidity (52.2%) was high, but related mainly to patient co-morbidity; postoperative mortality was reasonably low. Patients showing classical symptoms or immunocompromised patients should be considered for surgery. Encapsulated Aspergilloma without invasion of surrounding parenchyma requires no antifungal chemotherapy.

Quantum wave function reconstruction by free-electron spectral shearing interferometry.

The quantum wave function measurement of a free electron remains challenging in quantum mechanics and is subject to disputes about ψ-ontic/epistemic interpretations of the wave function. Here, we theoretically propose a realistic spectral method for reconstructing quantum wave function of an electron pulse, free-electron spectral shearing interferometry (FESSI). We use a Wien filter to generate two time-delayed replicas of the electron wave packet and then shift one replica in energy using a light-electron modulator driven by a mid-infrared laser. As a direct demonstration, we numerically reconstruct a pulsed electron wave function with a kinetic energy of 10 keV. FESSI is experimentally feasible and enables us to fully determine distinct orders of spectral phases and their physical implications in quantum foundations and quantum technologies, providing a universal approach to characterize ultrashort electron pulses.