[Interdisciplinary defect reconstruction of upper aerodigestive fistulas-case series and treatment algorithm]

BACKGROUND

Persistent complex defects and dysfunctions of the upper aerodigestive tract after tumor surgery represent a major challenge. The aim of this study was to evaluate the effectiveness of an interdisciplinary approach using the free anterolateral thigh flap (ALT) as a reconstruction option in the upper aerodigestive tract.

MATERIALS AND METHODS

The retrospective study identified 5 patients with complex defects after laryngectomy/pharyngolaryngectomy (LE/PLE) and multiple revision surgeries between 2017 and 2023. The operations were performed by an interdisciplinary team from otolaryngology, plastic surgery, and visceral/thoracic surgery. The results of the microsurgical reconstruction were analyzed.

RESULTS

There was an average of six previous operations. The defects included tracheoesophageal fistulas, pharyngocutaneous fistulas, neopharyngeal stenosis, and combinations thereof. Successful reconstruction was achieved in 100% of patients using the ALT flap. In 2 patients, ALT flow-through flaps were used with an additional free jejunal interposition (JI) and in 3 patients split-ALT flaps were used. The major complication rate was 40% and the minor complication rate was 20%.

CONCLUSION

Complex defects of the upper aerodigestive tract with multiple previous operations can be successfully reconstructed. Because of its versatility, the ALT flap seems to be a very good option. Prerequisite for this is an interdisciplinary treatment approach with a critical assessment of patient- and disease-specific factors.

Updated normative data for the EORTC QLQ-C30 in the general Dutch population by age and sex: a cross-sectional panel research study

PURPOSE

The European Organisation for Research and Treatment of Cancer (EORTC) quality of life core questionnaire (QLQ-C30) is a validated and widely-used Patient-Reported Outcome Measure for measuring the health-related quality of life (HRQoL) of cancer patients. To facilitate interpretation of results obtained in studies using the EORTC QLQ-C30, we generated normative data for the Dutch general population, stratified by age and sex.

METHODS

Dutch participants were selected from a larger cross-sectional online panel research study collecting EORTC QLQ-C30 general population normative data across 15 countries. EORTC QLQ-C30 raw scores based on a 4-point response scale were transformed to linear scores ranging from 0 to 100. Transformed scores were weighted based on the United Nations population distribution statistics and presented by age and sex/age. Differences in scale scores of ≥ 10 points in HRQoL were applied to indicate clinical relevance.

RESULTS

One thousand respondents completed the online survey. Stratified by age, clinically meaningful differences were observed, with worse physical functioning scores and better emotional functioning scores with increased age. Symptom scores remained stable across age groups, except for small age differences observed for fatigue, nausea/vomiting, diarrhoea, and financial difficulties. Stratified by sex/age, men generally scored better for both functioning and symptoms. However, these differences were not clinically meaningful.

CONCLUSIONS

These updated normative EORTC QLQ-C30 for the Dutch general population can be used to better interpret HRQoL data obtained from Dutch cancer patients. Being part of a larger international study, these data can further be used for inter-country comparisons in multi-national studies.

Tremor, Daily Functioning, and Health-Related Quality of Life in Solid Organ Transplant Recipients

Solid organ transplant recipients (SOTR) frequently report tremor. Data concerning tremor-related impairment and its potential impact on health-related quality of life (HRQoL) are lacking. This cross-sectional study assesses impact of tremor on activities of daily living and HRQoL using validated questionnaires among SOTR enrolled in the TransplantLines Biobank and Cohort Study. We included 689 SOTR (38.5% female, mean [±SD] age 58 [±14] years) at median [interquartile range] 3 [1-9] years after transplantation, of which 287 (41.7%) reported mild or severe tremor. In multinomial logistic regression analyses, whole blood tacrolimus trough concentration was an independent determinant of mild tremor (OR per µg/L increase: 1.11, 95% CI: 1.02 to 1.21, p = 0.019). Furthermore, in linear regression analyses, severe tremor was strongly and independently associated with lower physical and mental HRQoL (β = -16.10, 95% CI: -22.23 to -9.98, p < 0.001 and β = -12.68, 95% CI: -18.23 to -7.14, p < 0.001 resp.). SOTR frequently report tremor-related impairment of activities of daily living. Tacrolimus trough concentrations appeared as a main determinant of tremor among SOTR. The strong and independent association of tremor-related impairment with lower HRQoL warrants further studies into the effects of tacrolimus on tremor. Clinical Trial Registration: ClinicalTrials.gov, Identifier NCT03272841.

Ultrashort pulse written fiber Bragg gratings as narrowband filters in multicore fibers

We present the inscription of narrow-linewidth fiber Bragg gratings (FBGs) into different types of multicore fibers (MCFs) using ultrashort laser pulses and the phase mask technique, which can act as notch filters. Such filters are required, e.g., to suppress light emitted by hydroxyl in the Earth's upper atmosphere, which disturbs ground-based observation of extraterrestrial objects in the near infrared. However, the inscription into a commercially available seven-core fiber showed a quite large core-to-core deviation of the resonance wavelength of up to 0.45 nm. Two options are presented to overcome this: first, we present the photo-treatment of the FBGs to tune the resonance wavelength, which allows for sufficient resonance shifts. Second, adapted MCFs containing 12 cores, arranged on a circle, are fabricated. For this, two different fabrication procedures were investigated, namely, the mechanical drilling of the preform for a rod-in-tube version as well as a stack-and-draw approach. Both adapted MCFs yielded significant improvements with core-to-core wavelength variations of the FBGs of only about 0.18 nm and 0.11 nm, respectively, sufficient to fulfill the requirements for astronomical filter applications as discussed above.

Femtosecond inscription of semi-aperiodic multi-notch fiber Bragg gratings using a phase mask

We present an innovative concept of a semi-aperiodic phase mask design that enables the realization of multi-notch fiber Bragg gratings (FBG). This design utilizes the overlap and interference of near-infrared ultrashort laser pulses diffracted by short sequenced phase mask sections, which not only allows for a highly stable and reproducible inscription of a large number of wavelength filters but also paves the way towards full aperiodic phase masks. The semi-aperiodic FBG inscribed by this phase mask enables versatile notch filters showing multiple non-equidistant resonances. Those filters target applications, for instance in ground-based telescopes, where a large number of hydroxyl emission lines emitted in the upper atmosphere at near-infrared wavelengths restrict the observation of faint extraterrestrial objects.

Vibration threshold in non-diabetic subjects

Measuring vibration perception threshold (VPT) accurately classifies and quantifies the severity of loss of vibration perception. A biothesiometer (Bio-thesiometer®; Bio Medical Instrument Co, Ohio, USA) appears to be the most suitable tool to determine VPT due to its low inter-rater variability and low occurence of adaption to the sensation. Different VPT values for a biothesiometer have been described, however, specification on age, height and different measurement locations is currently lacking. The objective of our study was to identify determinants of vibration perception in non-diabetic subjects, in order to provide individualized normal values of VPTs for clinical practice. Measurements of the vibration perception were performed on the big toes, insteps, lateral malleoli, and wrists. A total of 205 healthy subjects were included (108 (52.7%) males) with a median [interquartile range] age of 59 [51;64] (range 21-80) years. Mean height was 174.45 ± 9.20 cm and mean weight was 82.94 ± 14.84 kg, resulting in a mean BMI of 27.19 ± 4.00 kg/m2. In stepwise forward linear regression analyses, age (st. β = 0.51, p < 0.001) and height (st. β = 0.43, p < 0.001) were found to be the independent unmodifiable determinants of the VPT at the big toe. Regression coefficients for quantiles of the determinants age and height were incorporated in the corresponding regression equations. This study provides equations to calculate age- and height-specific normal values for VPT that can be used in clinical practice and in large research studies.

Grazing mediates soil microbial activity and litter decomposition in salt marshes

Salt marshes contribute to climate change mitigation because of their great capacity to store organic matter (OM) in soils. Most of the research regarding OM turnover in salt marshes in times of global change focuses on effects of rising temperature and accelerated sea-level rise, while effects of land-use change have gained little attention. The present work investigates the mechanisms by which livestock grazing can affect OM decomposition in salt marsh soils. In a grazing exclusion experiment at the mouth of the Yangtze estuary, China, we assessed soil microbial exo-enzyme activity (EEA) to gain insight into the microbial carbon (C) and nitrogen (N) demand. Additionally, we studied the decomposition of plant litter in soil using the Tea Bag Index (TBI), a widely used standardized litter bag assay to fingerprint soil decomposition dynamics. Based on EEAs, grazing markedly reduced microbial C acquisition, whereas microbial N acquisition was strongly increased. These opposing grazing effects were also evident in the decomposition of standardized plant litter: The decomposition rate constant (k) and the stabilization (S) of litter were not inversely related, as would be expected, but instead both were reduced by livestock grazing. Our data suggest that gazing effects on EEAs and litter decomposition can just partly be explained by grazing-driven soil compaction and resulting lower oxygen availability, which has previously been hypothesized as a main pathway by which grazing can reduce microbial activity in wetland soils. Instead, grazing effects on microbial nutrient demand occurs to be an at least equally important control on soil decomposition processes.

General population normative data for the EORTC QLQ-C30 health-related quality of life questionnaire based on 15,386 persons across 13 European countries, Canada and the Unites States

OBJECTIVE

The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 health-related quality of life questionnaire is one of the most widely used cancer-specific health-related quality of life questionnaires worldwide. General population norm data can facilitate the interpretation of QLQ-C30 data obtained from cancer patients. This study aimed at systematically collecting norm data from the general population to develop European QLQ-C30 norm scores and to generate comparable norm data for individual countries in Europe and North America.

METHODS

We collected QLQ-C30 data from the general population across 11 European Union (EU) countries, Russia, Turkey, Canada and United States (n ≥ 1000/country). Representative samples were stratified by sex and age groups (18-39, 40-49, 50-59, 60-69 and ≥ 70 years). After applying weights based on the United Nations population distribution statistics, we calculated QLQ-C30 domain scores to generate a 'European QLQ-C30 Norm' based on the EU countries. Further, we calculated QLQ-C30 norm scores for all 15 individual countries.

RESULTS

A total of 15,386 respondents completed the online survey. For the EU sample, most QLQ-C30 domains showed differences by sex/age, with men scoring somewhat better health than women, while age effects varied across domains. Substantially larger differences were seen in inter-country comparisons, with Austrian and Dutch respondents reporting consistently better health compared with British and Polish respondents.

CONCLUSIONS

This study is the first to systematically collect EORTC QLQ-C30 general population norm data across Europe and North America applying a consistent data collection method across 15 countries. These new norm data facilitate valid intra-country as well as inter-country comparisons and QLQ-C30 score interpretation.

Inscribing diffraction gratings in bulk silicon with nanosecond laser pulses

Diffraction gratings are transversally inscribed in the bulk of monolithic crystalline silicon with infrared nanosecond laser pulses. Nanoscale material analyses of the modifications composing the gratings show that they rely on laser-induced stress associated with a positive refractive index change as confirmed with phase-shift interferometry. Characterizations of the optical properties of the gratings, including the diffraction angles and the efficiency of the different orders, are carried out. The refractive index change obtained from these measurements is in good agreement with the phase-shift measurements. Finally, we show that the grating diffraction efficiency depends strongly on the laser writing speed.

Inscription of silicon waveguides using picosecond pulses

Direct writing of single-mode waveguides into crystalline silicon using ps laser pulses is presented. The embedded structures were fabricated by moving the focal position along the beam axis with the help of a long distance microscope objective. In situ monitoring during inscription was performed to analyze the processing dynamics. The waveguide generation is based on pronounced multi-pulse interaction at moderate pulse energies around 100 nJ. All samples were characterized in terms of mode field distribution and damping losses. Calculations indicate an induced refractive index change in the range of 10^-3 to 10^-2. Moreover, a Y-splitter was realized to demonstrate the potential of this process.

Spatio-temporal analysis of glass volume processing using ultrashort laser pulses

Ultrashort laser pulses allow for the in-volume processing of glass through non-linear absorption, resulting in permanent material changes and the generation of internal stress. Across the manifold potential applications of this technology, process optimization requires a detailed understanding of the laser-matter interaction. Of particular relevance are the deposition of energy inside the material and the subsequent relaxation processes. In this paper, we investigate the spatio-temporal evolution of free carriers, energy transfer, and the resulting permanent modifications in the volume of glass during and after exposure to femtosecond and picosecond pulses. For this purpose, we employ time-resolved microscopy in order to obtain shadowgraphic and interferometric images that allow relating the transient distributions to the refractive index change profile. Whereas the plasma generation time is given by the pulse duration, the thermal dynamics occur over several microseconds. Among the most notable features is the emergence of a pressure wave due to the sudden increase of temperature and pressure within the interaction volume. We show how the structure of the modifications, including material disruptions as well as local defects, can be directly influenced by a judicious choice of pulse duration, pulse energy, and focus geometry.

Topologically protected bound states in photonic parity-time-symmetric crystals

Parity-time (PT)-symmetric crystals are a class of non-Hermitian systems that allow, for example, the existence of modes with real propagation constants, for self-orthogonality of propagating modes, and for uni-directional invisibility at defects. Photonic PT-symmetric systems that also support topological states could be useful for shaping and routing light waves. However, it is currently debated whether topological interface states can exist at all in PT-symmetric systems. Here, we show theoretically and demonstrate experimentally the existence of such states: states that are localized at the interface between two topologically distinct PT-symmetric photonic lattices. We find analytical closed form solutions of topological PT-symmetric interface states, and observe them through fluorescence microscopy in a passive PT-symmetric dimerized photonic lattice. Our results are relevant towards approaches to localize light on the interface between non-Hermitian crystals.

Interval cancers after skin cancer screening: incidence, tumour characteristics and risk factors for cutaneous melanoma

BACKGROUND

The rate of interval cancers is an established indicator for the performance of a cancer-screening programme.

METHODS

We examined the incidence, tumour characteristics and risk factors of melanoma interval cancers that occurred in participants of the SCREEN project, which was carried out 2003/2004 in Schleswig-Holstein, Germany. Data from 350 306 SCREEN participants, who had been screened negative for melanoma, were linked to data of the state cancer registry. Melanoma interval cancers were defined as melanomas diagnosed within 4-24 months after SCREEN examination. Results were compared with melanomas of the pre-SCREEN era (1999-2002), extracted from the cancer registry.

RESULTS

The overall relative incidence of melanoma interval cancers in terms of observed/expected ratio was 0.93 (95% CI: 0.82-1.05; in situ: 1.61 (1.32-1.95), invasive: 0.71 (0.60-0.84)). Compared with melanomas of the pre-SCREEN era, the interval melanomas were thinner and had a slightly greater proportion of lentigo maligna melanomas whereas nodular melanomas were less frequent.

INTERPRETATION

The results indicate a moderate performance of the SCREEN intervention with an excess of in situ melanomas. In part, the findings might be due to specifics of the SCREEN project, in particular a short-term follow-up of patients at high risk for melanoma.

The validation of a computer-adaptive test (CAT) for assessing health-related quality of life in children and adolescents in a clinical sample: study design, methods and first results of the Kids-CAT study

PURPOSE

Recently, we developed a computer-adaptive test (CAT) for assessing health-related quality of life (HRQoL) in children and adolescents: the Kids-CAT. It measures five generic HRQoL dimensions. The aims of this article were (1) to present the study design and (2) to investigate its psychometric properties in a clinical setting.

METHODS

The Kids-CAT study is a longitudinal prospective study with eight measurements over one year at two University Medical Centers in Germany. For validating the Kids-CAT, 270 consecutive 7- to 17-year-old patients with asthma (n = 52), diabetes (n = 182) or juvenile arthritis (n = 36) answered well-established HRQoL instruments (Pediatric Quality of Life Inventory™ (PedsQL), KIDSCREEN-27) and scales measuring related constructs (e.g., social support, self-efficacy). Measurement precision, test-retest reliability, convergent and discriminant validity were investigated.

RESULTS

The mean standard error of measurement ranged between .38 and .49 for the five dimensions, which equals a reliability between .86 and .76, respectively. The Kids-CAT measured most reliably in the lower HRQoL range. Convergent validity was supported by moderate to high correlations of the Kids-CAT dimensions with corresponding PedsQL dimensions ranging between .52 and .72. A lower correlation was found between the social dimensions of both instruments. Discriminant validity was confirmed by lower correlations with non-corresponding subscales of the PedsQL.

CONCLUSIONS

The Kids-CAT measures pediatric HRQoL reliably, particularly in lower areas of HRQoL. Its test-retest reliability should be re-investigated in future studies. The validity of the instrument was demonstrated. Overall, results suggest that the Kids-CAT is a promising candidate for detecting psychosocial needs in chronically ill children.

Course of self-reported symptoms of 342 outpatients receiving medium- versus long-term psychodynamic psychotherapy

Background

The course of self-reported symptoms during medium- versus long-term psychodynamic psychotherapy has rarely been documented for outpatient settings. This observational study describes routine practice of ambulatory treatment in Germany and explores self-reported symptoms of a broad patient sample undergoing one (medium-term) versus two years (long-term) of psychodynamic psychotherapy.

Methods

Over four and a half years, longitudinal self-report symptom data were collected from 342 outpatients as part of a standardized documentation system. Self-report data were compared between patients receiving either medium-term or long-term psychodynamic psychotherapy.

Results

Routine care significantly decreased disease burden as reported by patients by small to medium effect sizes (ES) for depression (ES = 0.58), anxiety (ES = 0.49), obsessive-compulsive disorder (ES = 0.54), somatoform disorder (ES = 0.32), eating disorder (ES = 0.38). The majority of patients completed treatment after one year and showed medium-size changes. For a subgroup of patients with depressive and/or obsessive-compulsive disorder symptoms for whom two years of therapy were deemed necessary, additional benefits were reported during the second year of treatment (ES = 0.61 and ES  0.47, respectively).

Conclusions

Our findings suggest that both medium- and long-term psychodynamic psychotherapy decrease self-reported disease burden of patients with depression, anxiety, obsessive-compulsive, somatoform and/or eating disorders. For a subgroup of patients, additional benefits were gained in the second year of treatment.

Implementation of the Kids-CAT in clinical settings: a newly developed computer-adaptive test to facilitate the assessment of patient-reported outcomes of children and adolescents in clinical practice in Germany

PURPOSE

To describe the implementation process of a computer-adaptive test (CAT) for measuring health-related quality of life (HRQoL) of children and adolescents in two pediatric clinics in Germany. The study focuses on the feasibility and user experience with the Kids-CAT, particularly the patients' experience with the tool and the pediatricians' experience with the Kids-CAT Report.

METHODS

The Kids-CAT was completed by 312 children and adolescents with asthma, diabetes or rheumatoid arthritis. The test was applied during four clinical visits over a 1-year period. A feedback report with the test results was made available to the pediatricians. To assess both feasibility and acceptability, a multimethod research design was used. To assess the patients' experience with the tool, the children and adolescents completed a questionnaire. To assess the clinicians' experience, two focus groups were conducted with eight pediatricians.

RESULTS

The children and adolescents indicated that the Kids-CAT was easy to complete. All pediatricians reported that the Kids-CAT was straightforward and easy to understand and integrate into clinical practice; they also expressed that routine implementation of the tool would be desirable and that the report was a valuable source of information, facilitating the assessment of self-reported HRQoL of their patients.

CONCLUSIONS

The Kids-CAT was considered an efficient and valuable tool for assessing HRQoL in children and adolescents. The Kids-CAT Report promises to be a useful adjunct to standard clinical care with the potential to improve patient-physician communication, enabling pediatricians to evaluate and monitor their young patients' self-reported HRQoL.

On the validity of measuring change over time in routine clinical assessment: a close examination of item-level response shifts in psychosomatic inpatients

OBJECTIVE

Significant life events such as severe health status changes or intensive medical treatment often trigger response shifts in individuals that may hamper the comparison of measurements over time. Drawing from the Oort model, this study aims at detecting response shift at the item level in psychosomatic inpatients and evaluating its impact on the validity of comparing repeated measurements.

STUDY DESIGN AND SETTING

Complete pretest and posttest data were available from 1188 patients who had filled out the ICD-10 Symptom Rating (ISR) scale at admission and discharge, on average 24 days after intake. Reconceptualization, reprioritization, and recalibration response shifts were explored applying tests of measurement invariance. In the item-level approach, all model parameters were constrained to be equal between pretest and posttest. If non-invariance was detected, these were linked to the different types of response shift.

RESULTS

When constraining across-occasion model parameters, model fit worsened as indicated by a significant Satorra-Bentler Chi-square difference test suggesting potential presence of response shifts. A close examination revealed presence of two types of response shift, i.e., (non)uniform recalibration and both higher- and lower-level reconceptualization response shifts leading to four model adjustments.

CONCLUSIONS

Our analyses suggest that psychosomatic inpatients experienced some response shifts during their hospital stay. According to the hierarchy of measurement invariance, however, only one of the detected non-invariances is critical for unbiased mean comparisons over time, which did not have a substantial impact on estimating change. Hence, the use of the ISR can be recommended for outcomes assessment in clinical routine, as change score estimates do not seem hampered by response shift effects.

Towards femtosecond laser written arrayed waveguide gratings

The fabrication of arrayed waveguide gratings (AWGs) using the femtosecond laser direct-write technique is investigated. We successfully demonstrate the fabrication of large planar waveguides that act as 2D free propagation zones. These slabs were found to have a highly uniform refractive index with a standard deviation of 1.97% relative to the total index contrast. The incorporation of low loss linear adiabatic tapers resulted in an increase of transmission by 90%. Strategies for manufacturing integrated laser written AWGs using continuous contouring to avoid lossy defects are discussed and demonstrated.

Radiation-loss management in modulated waveguides

In this work, we discuss the management of radiation loss in photonic waveguides. As an experimental basis, we introduce a new technique of fabricating waveguides with tunable loss, which is particularly useful when implementing non-Hermitian (PT-symmetric) systems. To this end, we employ laser-written waveguides with a transverse sinusoidal modulation, which causes well-controllable radiation losses of almost arbitrary amount. Numerical simulations support our experimental findings. Our study shows that the radiation loss not only depends on the local waveguide curvature but also is influenced by interference effects. As a consequence, the loss is a nonmonotonous function of the bending parameters, such as period length.

Laser-generated broadband antireflection structures for freeform silicon lenses at terahertz frequencies

We present a flexible technology to generate broadband antireflection (AR) structures for the terahertz (THz) frequency range on planar and curved surfaces of silicon optics. Ultrashort laser pulses are used to ablate the surface to form a pattern of conical pillars with a period of 30 μm. These subwavelength structures act as an effective medium with gradual transition of the refractive index from air to silicon, which reduces the Fresnel reflection losses. The characterization with the THz time-domain spectroscopy system shows an AR effect for a frequency range of 0.1-1.5 THz with a maximum enhancement of the spectral amplitude by ca. 32% at 0.4 THz for planar surfaces. In addition, we demonstrate laser-generated AR structures on convex silicon lenses of both photoconductive emitter and detector devices. Here, the THz pulse amplitude can be increased by about 28%, and single frequencies even show an improvement of the spectral amplitude up to 58%.

Measurement of stable changes of self-management skills after rehabilitation: a latent state-trait analysis of the Health Education Impact Questionnaire (heiQ™)

PURPOSE

To assess stable effects of self-management programs, measurement instruments should primarily capture the attributes of interest, for example, the self-management skills of the measured persons. However, measurements of psychological constructs are always influenced by both aspects of the situation (states) and aspects of the person (traits). This study tests whether the Health Education Impact Questionnaire (heiQ™), an instrument assessing a wide range of proximal outcomes of self-management programs, is primarily influenced by person factors instead of situational factors. Furthermore, measurement invariance over time, changes in traits and predictors of change for each heiQ™ scale were examined.

METHODS

Subjects were N = 580 patients with rheumatism, asthma, orthopedic conditions or inflammatory bowel disease, who filled out the heiQ™ at the beginning, the end of and 3 months after a disease-specific inpatient rehabilitation program in Germany. Structural equation modeling techniques were used to estimate latent trait-change models and test for measurement invariance in each heiQ™ scale. Coefficients of consistency, occasion specificity and reliability were computed.

RESULTS

All scales showed scalar invariance over time. Reliability coefficients were high (0.80-0.94), and consistency coefficients (0.49-0.79) were always substantially higher than occasion specificity coefficients (0.14-0.38), indicating that the heiQ™ scales primarily capture person factors. Trait-changes with small to medium effect sizes were shown in five scales and were affected by sex, age and diagnostic group.

CONCLUSION

The heiQ™ can be used to assess stable effects in important outcomes of self-management programs over time, e.g., changes in self-management skills or emotional well-being.

Photonic coherent state transfer with Hamiltonian dynamics

We report the observation of near-perfect light wave transfer by emulating quantum state transfer on a lattice with Hamiltonian dynamics, i.e., time-dependent intersite couplings. The structure transferring a single waveguide excitation over 11 sites with a fidelity of 0.93 works for classical light as well as single photons. As our implementation of perfect quantum state transfer uses a photonic setting, we introduce polarization as a new degree of freedom to the transport protocol. We demonstrate rotation operations of up to 40° on polarization during state transfer.

Superballistic growth of the variance of optical wave packets

We experimentally demonstrate that hybrid ordered-disordered photonic lattices can generate faster than the ballistic growth of the second moment of a spreading wave packet for parametrically large time intervals.

[Collection and processing of personal data to evaluate cancer screening programmes - results of a survey of the German population in light of the bill 'early detection of cancer and cancer registries']

In a representative German sample, 62.1% of participants of cancer screening interventions indicated willingness to provide personal data for data-linkage with cancer registries. An agreement of over 90% is deemed necessary to conduct a meaningful population-based evaluation. The 'early detection of cancer and cancer regis-tries' bill proposed a procedure based on the use of pseudonyms only. This way personal consent is not required but participants are granted the right to object.

Probing timescales during back side ablation of Molybdenum thin films with optical and electrical measurement techniques

In this study we present a new measurement technique to investigate the timescales of back side ablation of conductive films, using Molybdenum as an application example from photovoltaics. With ultrashort laser pulses at fluences below 0.6 J/cm(2), we ablate the Mo film in the shape of a fully intact Mo 'disc' from a transparent substrate. By monitoring the time-dependent current flow across a specifically developed test structure, we determine the time required for the lift-off of the disc. This value decreases with increasing laser fluence down to a minimum of 21 ± 2 ns. Furthermore, we record trajectories of the discs using a shadowgraphic setup. Ablated discs escape with a maximum velocity of 150 ± 5 m/s whereas droplets of Mo forming at the center of the disc can reach velocities up to 710 ± 11 m/s.

Self-trapping threshold in disordered nonlinear photonic lattices

We investigate numerically and experimentally the influence of coupling disorder on the self-trapping dynamics in nonlinear one-dimensional optical waveguide arrays. The existence of a lower and upper bound of the effective average propagation constant allows for a generalized definition of the threshold power for the onset of soliton localization. When compared to perfectly ordered systems, this threshold is found to decrease in the presence of coupling disorder.

Einstein-Podolsky-Rosen spatial entanglement in ordered and anderson photonic lattices

We demonstrate quantum walks of a photon pair in a spatially extended Einstein-Podolsky-Rosen state coupled into an on-chip multiport photonic lattice. By varying the degree of entanglement we observe Anderson localization for pairs in a separable state and Anderson colocalization for pairs in an Einstein-Podolsky-Rosen entangled state. In the former case, each photon localizes independently, while in the latter neither photon localizes, but the pair colocalizes--revealing unexpected survival of the spatial correlations through strong disorder.

Vacuum instability and pair production in an optical setting

In the Dirac-sea picture, the physics of pair production and instability of the quantum electrodynamics vacuum in presence of an oscillating electric field resembles the phenomenon of interband transition of light waves in photonic superlattices induced by a geometric curvature. We realize a binary wave guide superlattice with a curved optical axis mimicking dynamical pair production induced by two counterpropagating ultrastrong laser pulses. Our optical analogue enables visualization of formation of electron-positron pair in physical space as splitting of a wave packet, originally representing an electron in the Dirac sea.

Biphoton generation in quadratic waveguide arrays: a classical optical simulation

Quantum entanglement became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality can be demonstrated on impressively large length scales, as photons travel with the speed of light and interact only weakly with their environment. Spontaneous parametric down-conversion (SPDC) in nonlinear crystals provides an efficient source for entangled photon pairs, so-called biphotons. However, SPDC can also be implemented in nonlinear arrays of evanescently coupled waveguides which allows the generation and the investigation of correlated quantum walks of such biphotons in an integrated device. Here, we analytically and experimentally demonstrate that the biphoton degrees of freedom are entailed in an additional dimension, therefore the SPDC and the subsequent quantum random walk in one-dimensional arrays can be simulated through classical optical beam propagation in a two-dimensional photonic lattice. Thereby, the output intensity images directly represent the biphoton correlations and exhibit a clear violation of a Bell-like inequality.

Optical analogues for massless dirac particles and conical diffraction in one dimension

We demonstrate that light propagating in an appropriately designed lattice can exhibit dynamics akin to that expected from massless relativistic particles as governed by the one-dimensional Dirac equation. This is accomplished by employing a waveguide array with alternating positive and negative effective coupling coefficients, having a band structure with two intersecting minibands. Through this approach optical analogues of massless particle-antiparticle pairs are experimentally realized. One-dimensional conical diffraction is also observed for the first time in this work.

Anderson cross-localization

We report Anderson localization in two-dimensional optical waveguide arrays with disorder in waveguide separation introduced along one axis of the array, in an uncorrelated fashion for each waveguide row. We show that the anisotropic nature of such disorder induces a strong localization along both array axes. The degree of localization in the cross-axis remains weaker than that in the direction in which disorder is introduced. This effect is illustrated both theoretically and experimentally.

Observation of the gradual transition from one-dimensional to two-dimensional Anderson localization

We study the gradual transition from one-dimensional (1D) to two-dimensional (2D) Anderson localization upon transformation of the dimensionality of disordered waveguide arrays. An effective transition from a 1D to a 2D system is achieved by increasing the number of rows forming the arrays. We observe that, for a given disorder level, Anderson localization becomes weaker with increasing numbers of rows-hence the effective dimension.

Negative coupling between defects in waveguide arrays

We report on the experimental demonstration of negative coupling constants between defect guides in a waveguide lattice. We find that coupling can only be negative if the defects are negative and an odd number of lattice sites is between the defect guides.

Anderson localization in a periodic photonic lattice with a disordered boundary

We investigate experimentally the light evolution inside a two-dimensional finite periodic array of weakly coupled optical waveguides with a disordered boundary. For a completely localized initial condition away from the surface, we find that the disordered boundary induces an asymptotic localization in the bulk, centered around the initial position of the input beam.

Skin cancer screening participation and impact on melanoma incidence in Germany--an observational study on incidence trends in regions with and without population-based screening

BACKGROUND

The SCREEN (Skin Cancer Research to provide Evidence for Effectiveness of Screening in Northern Germany) project involved population-wide skin cancer screening with whole-body examination by general physicians and dermatologists. It was conducted in the German state of Schleswig-Holstein (July 2003-June 2004), but not in the German state of Saarland.

METHODS

The population-based registries of Schleswig-Holstein and Saarland provided data on melanoma incidence before, during, and after SCREEN to assess the association of skin cancer screening with incidence.

RESULTS

Approximately 19% of the Schleswig-Holstein population participated in SCREEN (women: 27%, men: 10%). A total of 52% of all melanomas diagnosed during SCREEN in Schleswig-Holstein were detected as part of the project. Melanoma incidence increased during SCREEN (invasive melanoma in women: +8.9 per 100,000 (95% confidence intervals (CI): 6.1; 11.7); men: +4.0 per 100,000 (95% CI: 1.6; 6.4)) and decreased afterwards (women: -10.6 per 100,000 (95% CI: -13.3; -7.9); men: -4.1 per 100,000 (95% CI: -6.5; -1.7)). Similar changes were not observed in Saarland that had no such project. The differences between the two states were greatest among women, the group with the greater SCREEN participation.

CONCLUSION

The SCREEN project had a substantial impact on melanoma incidence. This is consistent with the impact of effective screening for other cancers.

Three-dimensional light bullets in arrays of waveguides

We report the first experimental observation of three-dimensional light bullets, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally modulated refractive index. Stringent evidence of the excitation of light bullets is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the light bullets to follow varying dispersion or diffraction conditions, until they leave their existence range and decay.

Wave localization at the boundary of disordered photonic lattices

We report on the experimental observation of reduced light-energy transport and disorder-induced localization close to a boundary of a truncated 1D disordered photonic lattice. Our observations uncover that a higher level of disorder near the boundary is required to obtain similar localization than in the bulk.