Long-Term Quality of Life after COVID-19 Infection: Cross-Sectional Study of Health Care Workers.

(1) Background: Post-COVID syndrome is defined as symptoms that occur simultaneously with or after a COVID-19 infection, last for 12 weeks, and are not due to another diagnosis. Limited data are available on people's long-term quality of life following a COVID-19 infection. The aim of this cross-sectional study was to investigate the long-term quality of life after COVID-19 among employees of a hospital in Germany and to identify risk factors. (2) Methods: A monocentric, cross-sectional study was conducted using the validated and digitized WHOQOL-BREF questionnaire via Netigate® between 10/2022 and 02/2023. Data on the quality of life and global health status were collected in the following four domains: physical health, mental health, social relationships, and the environment. (3) Results: The response rate was 73.8 % (923/1250). Furthermore, 63.4 % of the hospital staff respondents reported at least one persistent symptom after a COVID-19 infection, leading to significant differences in quality of life. Pre-existing conditions, persistent symptoms, and disabilities after a COVID-19 infection as well as a high BMI, no partnership, and a low educational level were found to significantly contribute to a low long-term quality of life. (4) Conclusions: Obesity, a lack of partnership, and a low level of education were independent risk factors for a lower quality of life post-COVID-19 infection in this cohort of hospital staff. Further multicenter studies are required to validate the incidence and their suitability as independent risk factors for post-COVID syndrome.

Control of the electron dynamics in solid-state high harmonic generation on ultrafast time scales by a polarization-skewed laser pulse.

Since high-order harmonic generation (HHG) from atoms depends sensitively on the polarization of the driving laser field, the polarization gating (PG) technique was developed and applied successfully to generate isolated attosecond pulses from atomic gases. The situation is, however, different in solid-state systems as it has been demonstrated that due to collisions with neighboring atomic cores of the crystal lattice strong HHG can be generated even by elliptically- and circularly-polarized laser fields. Here we apply PG to solid-state systems and find that the conventional PG technique is inefficient for the generation of isolated ultrashort harmonic pulse bursts. In contrast, we demonstrate that a polarization-skewed laser pulse is able to confine the harmonic emission to a time window of less than one-tenth of the laser cycle. This method provides a novel way to control HHG and to generate isolated attosecond pulses in solids.

Low-field onset of Wannier-Stark localization in a polycrystalline hybrid organic inorganic perovskite.

Methylammonium lead iodide perovskite (MAPbI3) is renowned for an impressive power conversion efficiency rise and cost-effective fabrication for photovoltaics. In this work, we demonstrate that polycrystalline MAPbI3s undergo drastic changes in optical properties at moderate field strengths with an ultrafast response time, via transient Wannier Stark localization. The distinct band structure of this material - the large lattice periodicity, the narrow electronic energy bandwidths, and the coincidence of these two along the same high-symmetry direction - enables relatively weak fields to bring this material into the Wannier Stark regime. Its polycrystalline nature is not detrimental to the optical switching performance of the material, since the least dispersive direction of the band structure dominates the contribution to the optical response, which favors low-cost fabrication. Together with the outstanding photophysical properties of MAPbI3, this finding highlights the great potential of this material in ultrafast light modulation and novel photonic applications.

Individualized Positive End-expiratory Pressure and Regional Gas Exchange in Porcine Lung Injury.

BACKGROUND: In acute respiratory failure elevated intraabdominal pressure aggravates lung collapse, tidal recruitment, and ventilation inhomogeneity. Low positive end-expiratory pressure (PEEP) may promote lung collapse and intrapulmonary shunting, whereas high PEEP may increase dead space by inspiratory overdistension. The authors hypothesized that an electrical impedance tomography-guided PEEP approach minimizing tidal recruitment improves regional ventilation and perfusion matching when compared to a table-based low PEEP/no recruitment and an oxygenation-guided high PEEP/full recruitment strategy in a hybrid model of lung injury and elevated intraabdominal pressure. METHODS: In 15 pigs with oleic acid-induced lung injury intraabdominal pressure was increased by intraabdominal saline infusion. PEEP was set in randomized order: (1) guided by a PEEP/inspired oxygen fraction table, without recruitment maneuver; (2) minimizing tidal recruitment guided by electrical impedance tomography after a recruitment maneuver; and (3) maximizing oxygenation after a recruitment maneuver. Single photon emission computed tomography was used to analyze regional ventilation, perfusion, and aeration. Primary outcome measures were differences in PEEP levels and regional ventilation/perfusion matching. RESULTS: Resulting PEEP levels were different (mean ± SD) with (1) table PEEP: 11 ± 3 cm H2O; (2) minimal tidal recruitment PEEP: 22 ± 3 cm H2O; and (3) maximal oxygenation PEEP: 25 ± 4 cm H2O; P < 0.001. Table PEEP without recruitment maneuver caused highest lung collapse (28 ± 11% vs. 5 ± 5% vs. 4 ± 4%; P < 0.001), shunt perfusion (3.2 ± 0.8 l/min vs. 1.0 ± 0.8 l/min vs. 0.7 ± 0.6 l/min; P < 0.001) and dead space ventilation (2.9 ± 1.0 l/min vs. 1.5 ± 0.7 l/min vs. 1.7 ± 0.8 l/min; P < 0.001). Although resulting in different PEEP levels, minimal tidal recruitment and maximal oxygenation PEEP, both following a recruitment maneuver, had similar effects on regional ventilation/perfusion matching. CONCLUSIONS: When compared to table PEEP without a recruitment maneuver, both minimal tidal recruitment PEEP and maximal oxygenation PEEP following a recruitment maneuver decreased shunting and dead space ventilation, and the effects of minimal tidal recruitment PEEP and maximal oxygenation PEEP were comparable.

Realization of all-optical vortex switching in exciton-polariton condensates.

Vortices are topological objects representing the circular motion of a fluid. With their additional degree of freedom, the vorticity, they have been widely investigated in many physical systems and different materials for fundamental interest and for applications in data storage and information processing. Vortices have also been observed in non-equilibrium exciton-polariton condensates in planar semiconductor microcavities. There they appear spontaneously or can be created and pinned in space using ring-shaped optical excitation profiles. However, using the vortex state for information processing not only requires creation of a vortex but also efficient control over the vortex after its creation. Here we demonstrate a simple approach to control and switch a localized polariton vortex between opposite states. In our scheme, both the optical control of vorticity and its detection through the orbital angular momentum of the emitted light are implemented in a robust and practical manner.

Bloch oscillations of multidimensional dark soliton wave packets and light bullets.

The robust propagation of dark solitonic waves featuring Bloch oscillations (BOs) in media with a Kerr nonlinearity is demonstrated. The models considered have a discrete refractive index gradient in one dimension and are continuous in the orthogonal direction or directions. Such systems can be realized in photonic settings, where temporal dispersion of a normal type is able to support dark solitons. The demonstrated effects may also appear in the dynamics of Bose-Einstein condensates (BECs), where dark solitons appear due to the joint action of diffraction and a self-defocusing nonlinearity. Furthermore, our analysis shows that a periodic variation of the refractive index gradient in the propagation direction allows us to realize the spatial analog of dynamical localization. In addition, we demonstrate that dark solitons serve as excellent supporters for light bullets of a peculiar dark-bright type that can also feature robust BOs.

Attosecond temporal confinement of interband excitation by intraband motion.

High order harmonic generation (HHG) in semiconductors opens a new frontier in strong field physics and attosecond science. However, the underlying physical mechanisms are not yet fully understood and lively debated. Here, we identify and discuss carrier-wave population transfer as a novel and important dynamical effect. We find that the interband excitation occurs in an extremely short time window due to the intraband motion. Our analysis based on this finding allows for a physically intuitive interpretation of the anomalous carrier-envelope phase dependence observed in HHG from MgO and to understand the dominant role of the interband polarization as reported in a series of recent semiconductor HHG experiments. Motivated by the discovered coupling mechanism, we demonstrate that the interband excitation can be controlled by an appropriately tailored two-color field. An ultrabroad supercontinuum spectrum covering the entire plateau region can be generated which directly creates an isolated-attosecond pulse even without phase compensation. Our results provide remarkable insight into the basic physics governing the sub-cycle electron motion with significant implications for the generation of isolated-attosecond light pulses in semiconductor materials.

Nonlinear integrated quantum electro-optic circuits.

Future quantum computation and networks require scalable monolithic circuits, which incorporate various advanced functionalities on a single physical substrate. Although substantial progress for various applications has already been demonstrated on different platforms, the range of diversified manipulation of photonic states on demand on a single chip has remained limited, especially dynamic time management. Here, we demonstrate an electro-optic device, including photon pair generation, propagation, electro-optical path routing, as well as a voltage-controllable time delay of up to ~12 ps on a single Ti:LiNbO3 waveguide chip. As an example, we demonstrate Hong-Ou-Mandel interference with a visibility of more than 93 ± 1.8%. Our chip not only enables the deliberate manipulation of photonic states by rotating the polarization but also provides precise time control. Our experiment reveals that we have full flexible control over single-qubit operations by harnessing the complete potential of fast on-chip electro-optic modulation.

Observation and Uses of Position-Space Bloch Oscillations in an Ultracold Gas.

We report the observation and characterization of position-space Bloch oscillations using cold atoms in a tilted optical lattice. While momentum-space Bloch oscillations are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically unresolvable. In a regime of rapid tunneling and low force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.

Treatment of postherpetic neuralgia with 5% lidocaine medicated plaster in elderly patients - subgroup analyses from three European clinical trials.

OBJECTIVE: To investigate short- and long-term effectiveness and safety of the 5% lidocaine medicated plaster in the treatment of postherpetic neuralgia (PHN) in elderly patients (≥70 years of age). METHODS: Data from three European clinical trials was compared after stratification according to age (<70 years and ≥70 years). Length of study phase investigated was 4 weeks for study 1, 8 weeks for study 2, and up to 12 months for study 3. Effectiveness outcome measures were pain intensity, pain relief, allodynia severity, Clinical Global Impression of Change, and Patient Global Impression of Change. Safety was assessed by adverse event documentation. RESULTS: Mean average pain intensity improved in the elderly by -2.1 (SD 2.1) vs. -2.5 (SD 2.0) for <70 year old patients after 4 weeks, by -1.4 (SD 1.8) vs. -1.7 (SD 1.3) after 8 weeks, and by -1.5 (SD 1.9) vs. -2.7 (SD 2.2) after 12 months. Most patients presented with allodynia (>85% of elderly, >78% of younger patients) which was described by >51% as painful or extremely painful. Allodynia severity was markedly reduced in both groups during all three trials. Drug-related adverse events occurred in <20% of elderly and <15% of <70 year old patients and were mainly skin related. CONCLUSIONS: The 5% lidocaine medicated plaster provided pain relief and marked reductions in allodynia severity in elderly PHN patients with an excellent safety profile under short- and long-term treatment supporting the addition of the plaster to the treatment armamentarium for this age group. STUDY LIMITATIONS: All analyzed study phases were open-label and lacking a placebo control group.

Two-dimensional symbiotic solitons and vortices in binary condensates with attractive cross-species interaction.

We consider a two-dimensional (2D) two-component spinor system with cubic attraction between the components and intra-species self-repulsion, which may be realized in atomic Bose-Einstein condensates, as well as in a quasi-equilibrium condensate of microcavity polaritons. Including a 2D spatially periodic potential, which is necessary for the stabilization of the system against the critical collapse, we use detailed numerical calculations and an analytical variational approximation (VA) to predict the existence and stability of several types of 2D symbiotic solitons in the spinor system. Stability ranges are found for symmetric and asymmetric symbiotic fundamental solitons and vortices, including hidden-vorticity (HV) modes, with opposite vorticities in the two components. The VA produces exceptionally accurate predictions for the fundamental solitons and vortices. The fundamental solitons, both symmetric and asymmetric ones, are completely stable, in either case when they exist as gap solitons or regular ones. The symmetric and asymmetric vortices are stable if the inter-component attraction is stronger than the intra-species repulsion, while the HV modes have their stability region in the opposite case.

Curvature effects in the band structure of carbon nanotubes including spin-orbit coupling.

The Kane-Mele model was previously used to describe effective spin-orbit couplings (SOCs) in graphene. Here we extend this model and also incorporate curvature effects to analyze the combined influence of SOC and curvature on the band structure of carbon nanotubes (CNTs). The extended model then reproduces the chirality-dependent asymmetric electron-hole splitting for semiconducting CNTs and in the band structure for metallic CNTs shows an opening of the band gap and a change of the Fermi wave vector with spin. For chiral semiconducting CNTs with large chiral angle we show that the spin-splitting configuration of bands near the Fermi energy depends on the value of mod(2n + m, 3).

Creation of vortices by torque in multidimensional media with inhomogeneous defocusing nonlinearity.

Recently, a new class of nonlinear systems was introduced, in which the self-trapping of fundamental and vortical localized modes in space of dimension D is supported by cubic self-repulsion with a strength growing as a function of the distance from the center, r, at any rate faster that r(D). These systems support robust 2D and 3D modes which either do not exist or are unstable in other nonlinear systems. Here we demonstrate a possibility to create solitary vortices in this setting by applying a phase-imprinting torque to the ground state. Initially, a strong torque completely destroys the ground state. However, contrary to usual systems, where the destruction is irreversible, the present ones demonstrate a rapid restabilization and the creation of one or several shifted vortices orbiting the center. For the sake of comparison, we show analytically that, in the linear system with a 3D trapping potential, the action of a torque on the ground state is inefficient and creates only even-vorticity states with a small probability.

Nonlinear dynamics of Airy-vortex 3D wave packets: emission of vortex light waves.

The dynamics of 3D Airy-vortex wave packets is studied under the action of strong self-focusing Kerr nonlinearity. Emissions of nonlinear 3D waves out of the main wave packets with the topological charges were demonstrated. Because of the conservation of the total angular momentum, charges of the emitted waves are equal to those carried by the parental light structure. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and nonzero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse.

Soliton gyroscopes in media with spatially growing repulsive nonlinearity.

We find that the recently introduced model of self-trapping supported by a spatially growing strength of a repulsive nonlinearity gives rise to robust vortex-soliton tori, i.e., three-dimensional vortex solitons, with topological charges S≥1. The family with S=1 is completely stable, while the one with S=2 has alternating regions of stability and instability. The families are nearly exactly reproduced in an analytical form by the Thomas-Fermi approximation. Unstable states with S=2 and 3 split into persistently rotating pairs or triangles of unitary vortices. Application of a moderate torque to the vortex torus initiates a persistent precession mode, with the torus' axle moving along a conical surface. A strong torque heavily deforms the vortex solitons, but, nonetheless, they restore themselves with the axle oriented according to the vectorial addition of angular momenta.

Bedside monitoring of ventilation distribution and alveolar inflammation in community-acquired pneumonia.

It is unclear whether bedside monitoring tools such as exhaled nitric oxide measurements (FENO) and electrical impedance tomography (EIT) could help guiding patient management in community-acquired pneumonia (CAP). We hypothesized that exhaled NO would be increased in CAP patients and could be used to assess resolution of inflammation in the course of CAP therapy. Feasibility of multiple-breath (mb) and single-breath (sb) approach has been investigated. EIT was compared with chest X-ray at admission and used to assess whether the inhomogeneous ventilation changes due to treatment. 24 CAP patients were enrolled. Measurements were accomplished at admission (T0: EIT + FENO), after 3 days (T1: FENO) and 5-6 days after admission (T2: EIT + FENO). We computed an EIT distribution index (DEIT), which reflects the uniformity of ventilation. FENO measurements showed a significant decrease in NO after the beginning of antibiotic therapy [p = 0.04 (sb); p = 0.003 (mb)]. Correlation between sb method and mb method was significant (p < 0.001, r = 0.70). EIT detects right-sided and left-sided ventilation disorders due to pneumonia in correspondence to chest X-ray (p < 0.01). EIT images at T2 showed a more homogeneous ventilation distribution in displayed EIT. FENO could be a prospective supplementary tool to describe local lung inflammation as individual trend parameter. EIT could be a suitable supplementary tool to monitor functional lung status in CAP.

The suitability of EIT to estimate EELV in a clinical trial compared to oxygen wash-in/wash-out technique.

INTRODUCTION: Open endotracheal suctioning procedure (OSP) and recruitment manoeuvre (RM) are known to induce severe alterations of end-expiratory lung volume (EELV). We hypothesised that EIT lung volumes lack clinical validity. We studied the suitability of EIT to estimate EELV compared to oxygen wash-in/wash-out technique. METHODS: Fifty-four postoperative cardiac surgery patients were enrolled and received standardized ventilation and OSP. Patients were randomized into two groups receiving either RM after suctioning (group RM) or no RM (group NRM). Measurements were conducted at the following time points: Baseline (T1), after suctioning (T2), after RM or NRM (T3), and 15 and 30 min after T3 (T4 and T5). We measured EELV using the oxygen wash-in/wash-out technique (EELVO2) and computed EELV from EIT (EELVEIT) by the following formula: EELVEITTx,y…=EELVO2+ΔEELI×VT/ΔZ. EELVEIT values were compared with EELVO2 using Bland-Altman analysis and Pearson correlation. RESULTS: Limits of agreement ranged from -0.83 to 1.31 l. Pearson correlation revealed significant results. There was no significant impact of RM or NRM on EELVO2-EELVEIT relationship (p=0.21; p=0.23). DISCUSSION: During typical routine respiratory manoeuvres like endotracheal suctioning or alveolar recruitment, EELV cannot be estimated by EIT with reasonable accuracy.

Photonic crystal waveguides intersection for resonant quantum dot optical spectroscopy detection.

Using a finite-difference time-domain method, we theoretically investigate the optical spectra of crossing perpendicular photonic crystal waveguides with quantum dots embedded in the central rod. The waveguides are designed so that the light mainly propagates along one direction and the cross talk is greatly reduced in the transverse direction. It is shown that when a quantum dot (QD) is resonant with the cavity, strong coupling can be observed via both the transmission and crosstalk spectrum. If the cavity is far off-resonant from the QD, both the cavity mode and the QD signal can be detected in the transverse direction since the laser field is greatly suppressed in this direction. This structure could have strong implications for resonant excitation and in-plane detection of QD optical spectroscopy.

Effect of PEEP on regional ventilation during laparoscopic surgery monitored by electrical impedance tomography.

BACKGROUND: Anesthesia per se and pneumoperitoneum during laparoscopic surgery lead to atelectasis and impairment of oxygenation. We hypothesized that a ventilation with positive end-expiratory pressure (PEEP) during general anesthesia and laparoscopic surgery leads to a more homogeneous ventilation distribution as determined by electrical impedance tomography (EIT). Furthermore, we supposed that PEEP ventilation in lung-healthy patients would improve the parameters of oxygenation and respiratory compliance. METHODS: Thirty-two patients scheduled to undergo laparoscopic cholecystectomy were randomly assigned to be ventilated with ZEEP (0 cmH(2)O) or with PEEP (10 cmH(2)O) and a subsequent recruitment maneuver. Differences in regional ventilation were analyzed by the EIT-based center-of-ventilation index (COV), which quantifies the distribution of ventilation and indicates ventilation shifts. RESULTS: Higher amount of ventilation was examined in the dorsal parts of the lungs in the PEEP group. Throughout the application of PEEP, a lower shift of ventilation was found, whereas after the induction of anesthesia, a remarkable ventral shift of ventilation in ZEEP-ventilated patients (COV: ZEEP, 40.6 ± 2.4%; PEEP, 46.5 ± 3.5%; P<0.001) was observed. Compared with the PEEP group, ZEEP caused a ventral misalignment of ventilation during pneumoperitoneum (COV: ZEEP, 41.6 ± 2.4%; PEEP, 44 ± 2.7%; P=0.013). Throughout the study, there were significant differences in the parameters of oxygenation and respiratory compliance with improved values in PEEP-ventilated patients. CONCLUSION: The effect of anesthesia, pneumoperitoneum, and different PEEP levels can be evaluated by EIT-based COV monitoring. An initial recruitment maneuver and a PEEP of 10 cmH(2)O preserved homogeneous regional ventilation during laparoscopic surgery in most, but not all, patients and improved oxygenation and respiratory compliance.

Functional residual capacity-guided alveolar recruitment strategy after endotracheal suctioning in cardiac surgery patients.

OBJECTIVE: To determine whether the results of functional residual capacity measurements after endotracheal suctioning could guide the decision to perform an alveolar recruitment maneuver and thus improve lung function. DESIGN: Prospective, randomized, controlled interventional study. SETTING: Intensive care unit of a university hospital. PATIENTS: Fifty-nine mechanically ventilated patients within 2 hrs after elective cardiac surgery without preexisting lung diseases. INTERVENTIONS: Patients received a standard suctioning procedure with disconnection of the ventilator (20 secs, 14 F catheter, 200 cm H2O negative pressure). Prospectively, patients were stratified into two groups by the postsuctioning functional residual capacity value (group A: functional residual capacity >94% of baseline; group B: functional residual capacity <94% of baseline). Both groups were randomized into either a recruitment maneuver (RM) group (positive end-expiratory pressure 15 cm H2O, peak inspiratory pressure 35-40 cm H2O for 30 secs, group RM) or a non-RM group, in which ventilation was resumed without an RM (group NRM), resulting in four groups. MEASUREMENTS AND MAIN RESULTS: Functional residual capacity and arterial blood gases were recorded for up to 1 hr. In addition, distribution of ventilation was measured by means of electrical impedance tomography. The RM had an impact on distribution of ventilation, functional residual capacity, and oxygenation in patients with a decrease of functional residual capacity after suctioning. In contrast, the RM showed no impact on these parameters in patients with no decrease of functional residual capacity after suctioning. CONCLUSIONS: By measurements of functional residual capacity after endotracheal suctioning, patients profiting from a consecutive recruitment maneuver could be identified. Guiding the recruitment strategy on changes of functional residual capacity may improve patient care.