X-ray beam diagnostics at the MID instrument of the European X-ray Free-Electron Laser Facility.

The Materials Imaging and Dynamics (MID) instrument at the European X-ray Free-Electron Laser Facility (EuXFEL) is equipped with a multipurpose diagnostic end-station (DES) at the end of the instrument. The imager unit in DES is a key tool for aligning the beam to a standard trajectory and for adjusting optical elements such as focusing lenses or the split-and-delay line. Furthermore, the DES features a bent-diamond-crystal spectrometer to disperse the spectrum of the direct beam to a line detector. This enables pulse-resolved characterization of the EuXFEL spectrum to provide X-ray energy calibration, and the spectrometer is particularly useful in commissioning special modes of the accelerator. Together with diamond-based intensity monitors, the imager and spectrometer form the DES unit which also contains a heavy-duty beamstop at the end of the MID instrument. Here, we describe the setup in detail and provide exemplary beam diagnostic results.

Real-time swelling-collapse kinetics of nanogels driven by XFEL pulses.

Stimuli-responsive polymers are an important class of materials with many applications in nanotechnology and drug delivery. The most prominent one is poly-N-isopropylacrylamide (PNIPAm). The characterization of the kinetics of its change after a temperature jump is still a lively research topic, especially at nanometer-length scales where it is not possible to rely on conventional microscopic techniques. Here, we measured in real time the collapse of a PNIPAm shell on silica nanoparticles with megahertz x-ray photon correlation spectroscopy at the European XFEL. We characterize the changes of the particles diffusion constant as a function of time and consequently local temperature on sub-microsecond timescales. We developed a phenomenological model to describe the observed data and extract the characteristic times associated to the swelling and collapse processes. Different from previous studies tracking the turbidity of PNIPAm dispersions and using laser heating, we find collapse times below microsecond timescales and two to three orders of magnitude slower swelling times.

Reliability, Knowledge Translation, and Implementability of the Spanish Version of the Hammersmith Infant Neurological Examination.

Purpose. This study aimed to: (a) translate and cross-culturally adapt the Hammersmith Infant Neurological Examination (HINE) into Spanish; (b) evaluate its intra- and inter-examiner reliability; (c) support a knowledge translation and tool implementation program in early intervention; and (d) evaluate its reliability and implementation for professionals one year after receiving training. Materials and methods. The translation followed the World Health Organization's recommendations. Reliability was assessed in 25 infants aged between 3 and 15 months with identifiable risks of cerebral palsy (CP). The implementation was also evaluated by analyzing the reliability of professionals without previous experience of the tool by using a pre-survey and a follow-up survey one year after training. The survey covered aspects related to the use of early detection tools of CP and the use of HINE, including attitudes, opinions, and perceptions. Results. An excellent intra- and inter-examiner agreement was obtained for the total score of the HINE intra-class correlation coefficient (ICC = 0.98 in both indices). One year after training, the professionals also showed excellent reliability values (ICC = 0.99), as well as an increase in sensitization and skills in evidence-based practices for the early detection of "high risk" of CP. Conclusions. The Spanish version of HINE is a reliable measure for the neurological evaluation of "high risk" of CP and can be administered after standardized training and without costs to acquire the evaluation. This allows its accessible and widespread implementation in the clinical context.

Resonant X-ray excitation of the nuclear clock isomer 45Sc.

Resonant oscillators with stable frequencies and large quality factors help us to keep track of time with high precision. Examples range from quartz crystal oscillators in wristwatches to atomic oscillators in atomic clocks, which are, at present, our most precise time measurement devices1. The search for more stable and convenient reference oscillators is continuing2-6. Nuclear oscillators are better than atomic oscillators because of their naturally higher quality factors and higher resilience against external perturbations7-9. One of the most promising cases is an ultra-narrow nuclear resonance transition in 45Sc between the ground state and the 12.4-keV isomeric state with a long lifetime of 0.47 s (ref. 10). The scientific potential of 45Sc was realized long ago, but applications require 45Sc resonant excitation, which in turn requires accelerator-driven, high-brightness X-ray sources11 that have become available only recently. Here we report on resonant X-ray excitation of the 45Sc isomeric state by irradiation of Sc-metal foil with 12.4-keV photon pulses from a state-of-the-art X-ray free-electron laser and subsequent detection of nuclear decay products. Simultaneously, the transition energy was determined as [Formula: see text] with an uncertainty that is two orders of magnitude smaller than the previously known values. These advancements enable the application of this isomer in extreme metrology, nuclear clock technology, ultra-high-precision spectroscopy and similar applications.

Clinical and Functional Characteristics of a New Phenotype of SMA Type I among a National Sample of Spanish Children: A Cross-Sectional Study.

Spinal Muscular Atrophy (SMA) type I has classically presented extremely severe clinical features. New pharmacological treatments have led to a new phenotype of SMA. The aim of this study was to describe the current health and functional status of children with SMA. A cross-sectional study was conducted based on the STROBE guidelines. Patient questionnaires and standardized tools were used. A descriptive analysis was conducted establishing the proportions of subjects for each of the characteristics of interest. In total, 51 genetically confirmed SMA type I subjects were included. Fifty-seven percent received oral feeding, 33% received tube feeding and 10% combined both. Moreover, 21.6% had tracheostomies, and 9.8% needed more than 16 h/d ventilatory support. Regarding orthopedic status, 66.7% had scoliosis, and 68.6% had hip subluxation or dislocation. Up to 67% were able to sit independently, 23.5% walked with support and one child walked independently. Current SMA type I is a different entity from the classic phenotype but also from types II and III. In addition, no differences were found between SMA type I subgroups. These findings may enable the professionals involved in the care of these patients to improve their interventions in terms of prevention and rehabilitation measures for these children.

A sensitive high repetition rate arrival time monitor for X-ray free electron lasers.

X-ray free-electron laser sources enable time-resolved X-ray studies with unmatched temporal resolution. To fully exploit ultrashort X-ray pulses, timing tools are essential. However, new high repetition rate X-ray facilities present challenges for currently used timing tool schemes. Here we address this issue by demonstrating a sensitive timing tool scheme to enhance experimental time resolution in pump-probe experiments at very high pulse repetition rates. Our method employs a self-referenced detection scheme using a time-sheared chirped optical pulse traversing an X-ray stimulated diamond plate. By formulating an effective medium theory, we confirm subtle refractive index changes, induced by sub-milli-Joule intense X-ray pulses, that are measured in our experiment. The system utilizes a Common-Path-Interferometer to detect X-ray-induced phase shifts of the optical probe pulse transmitted through the diamond sample. Owing to the thermal stability of diamond, our approach is well-suited for MHz pulse repetition rates in superconducting linear accelerator-based free-electron lasers.

Ultrafast Energy Transfer from Photoexcited Tryptophan to the Haem in Cytochrome c.

We report femtosecond Fe K-edge absorption (XAS) and nonresonant X-ray emission (XES) spectra of ferric cytochrome C (Cyt c) upon excitation of the haem (>300 nm) or mixed excitation of the haem and tryptophan (<300 nm). The XAS and XES transients obtained in both excitation energy ranges show no evidence for electron transfer processes between photoexcited tryptophan (Trp) and the haem, but rather an ultrafast energy transfer, in agreement with previous ultrafast optical fluorescence and transient absorption studies. The reported (J. Phys. Chem. B 2011, 115 (46), 13723-13730) decay times of Trp fluorescence in ferrous (∼350 fs) and ferric (∼700 fs) Cyt c are among the shortest ever reported for Trp in a protein. The observed time scales cannot be rationalized in terms of Förster or Dexter energy transfer mechanisms and call for a more thorough theoretical investigation.

Resolving molecular diffusion and aggregation of antibody proteins with megahertz X-ray free-electron laser pulses.

X-ray free-electron lasers (XFELs) with megahertz repetition rate can provide novel insights into structural dynamics of biological macromolecule solutions. However, very high dose rates can lead to beam-induced dynamics and structural changes due to radiation damage. Here, we probe the dynamics of dense antibody protein (Ig-PEG) solutions using megahertz X-ray photon correlation spectroscopy (MHz-XPCS) at the European XFEL. By varying the total dose and dose rate, we identify a regime for measuring the motion of proteins in their first coordination shell, quantify XFEL-induced effects such as driven motion, and map out the extent of agglomeration dynamics. The results indicate that for average dose rates below 1.06 kGy µs-1 in a time window up to 10 µs, it is possible to capture the protein dynamics before the onset of beam induced aggregation. We refer to this approach as correlation before aggregation and demonstrate that MHz-XPCS bridges an important spatio-temporal gap in measurement techniques for biological samples.

Multi-modal characterization of kesterite thin-film solar cells: experimental results and numerical interpretation.

We report a multi-modal study of the electrical, chemical and structural properties of a kesterite thin-film solar cell by combining the spatially-resolved X-ray beam induced current and fluorescence imaging techniques for the evaluation of a fully functional device on a cross-section. The data allowed the correlation of the chemical composition, defects at interfaces and inhomogeneous deposition of the layers with the local charge-collection efficiency of the device. We support our observations with Monte Carlo simulations of high-energy X-ray interactions with the semiconductor device, and finite-volume modeling of the charge-collection efficiency.

Design and performance of a dedicated coherent X-ray scanning diffraction instrument at beamline NanoMAX of MAX IV.

The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick-Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm. The endstation, in continued development, has been in user operation since summer 2017.

Active Cervical Range of Motion in Babies with Positional Plagiocephaly: Analytical Cross-Sectional Study.

Positional plagiocephaly (PP) is a general term describing cranial distortion from pre- or postnatal forces on the infant head. Abnormal intrauterine forces, multiple births, primiparous mothers, obstetric interventions, prematurity, male sex, excessive time lying in the supine position, and mobility restrictions of the cervical spine have been considered as the main predisposing factors. The objective was to investigate the association between the severity of PP and the active cervical rotation and to analyze the influence of predisposing factors in babies with PP. An analytical cross-sectional study was performed on 74 babies with moderate PP. Clinical and demographic data, cranial vault asymmetry, and active cervical rotation range of motion (ROM) were measured. Associations were analyzed with generalized linear models. The mean age was 16.8 ± 5.0 weeks, and 56.8% were male. A restriction in the ROM of active cervical rotation, especially to the left side, was observed. Our models showed that cranial asymmetry was related with left active cervical rotation ROM (p = 0.034) and with being transported in a pushchair (p < 0.001). Conclusions: An increased severity of PP was related with being transported in a baby pushchair and with a reduced active cervical rotation ROM toward the most restricted side.

NanoMAX: the hard X-ray nanoprobe beamline at the MAX IV Laboratory.

NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world's first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.

Imaging Ultrafast Dynamical Diffraction Wave Fronts in Strained Si with Coherent X Rays.

Dynamical diffraction effects in thin single crystals produce highly monochromatic parallel x-ray beams with a mutual separation of a few microns and a time delay of a few femtoseconds-the so-called echoes. This ultrafast diffraction effect is used at X-Ray Free Electron Lasers in self-seeding schemes to improve beam monochromaticity. Here, we present a coherent x-ray imaging measurement of echoes from Si crystals and demonstrate that a small surface strain can be used to tune their temporal delay. These results represent a first step toward the ambitious goal of strain tailoring new x-ray optics and, conversely, open up the possibility of using ultrafast dynamical diffraction effects to study strain in materials.

Microsecond hydrodynamic interactions in dense colloidal dispersions probed at the European XFEL.

Many soft-matter systems are composed of macromolecules or nanoparticles suspended in water. The characteristic times at intrinsic length scales of a few nanometres fall therefore in the microsecond and sub-microsecond time regimes. With the development of free-electron lasers (FELs) and fourth-generation synchrotron light-sources, time-resolved experiments in such time and length ranges will become routinely accessible in the near future. In the present work we report our findings on prototypical soft-matter systems, composed of charge-stabilized silica nanoparticles dispersed in water, with radii between 12 and 15 nm and volume fractions between 0.005 and 0.2. The sample dynamics were probed by means of X-ray photon correlation spectroscopy, employing the megahertz pulse repetition rate of the European XFEL and the Adaptive Gain Integrating Pixel Detector. We show that it is possible to correctly identify the dynamical properties that determine the diffusion constant, both for stationary samples and for systems driven by XFEL pulses. Remarkably, despite the high photon density the only observable induced effect is the heating of the scattering volume, meaning that all other X-ray induced effects do not influence the structure and the dynamics on the probed timescales. This work also illustrates the potential to control such induced heating and it can be predicted with thermodynamic models.

Efficacy of pediatric integrative manual therapy in positional plagiocephaly: a randomized controlled trial.

BACKGROUND: Positional plagiocephaly frequently affects healthy babies. It is hypothesized that manual therapy tailored to pediatrics is more effective in improving plagiocephalic cranial asymmetry than just repositioning and sensory and motor stimulation. METHODS: Thirty-four neurologically healthy subjects aged less than 28 weeks old with a difference of at least 5 mm between cranial diagonal diameters were randomly distributed into 2 groups. For 10 weeks, the pediatric integrative manual therapy (PIMT) group received manual therapy plus a caregiver education program, while the controls received the same education program exclusively. Cranial shape was evaluated using anthropometry; cranial index (CI) and cranial vault asymmetry index (CVAI) were calculated. Parental perception of change was assessed using a visual analogue scale (- 10 cm to + 10 cm). RESULTS: CVAI presented a greater decrease in PIMT group: 3.72 ± 1.40% compared with 0.34 ± 1.72% in the control group (p = 0.000). CI did not present significant differences between groups. Manual therapy led to a more positive parental perception of cranial changes (manual therapy: 6.66 ± 2.07 cm; control: 4.25 ± 2.31 cm; p = 0.004). CONCLUSION: Manual therapy plus a caregiver education program improved CVAI and led to parental satisfaction more effectively than solely a caregiver education program. TRIAL REGISTRATION: Trial registration number: NCT03659032 ; registration date: September 1, 2018. Retrospectively registered.

Effectiveness of pediatric integrative manual therapy in cervical movement limitation in infants with positional plagiocephaly: a randomized controlled trial.

BACKGROUND: Positional plagiocephaly (PP) is a cranial deformation frequent amongst children and consisting in a flattened and asymmetrical head shape. PP is associated with excessive time in supine and with congenital muscular torticollis (CMT). Few studies have evaluated the efficiency of a manual therapy approach in PP. The purpose of this parallel randomized controlled trial is to compare the effectiveness of adding a manual therapy approach to a caregiver education program focusing on active rotation range of motion (AROM) and neuromotor development in a PP pediatric sample. METHODS: Thirty-four children with PP and less than 28 week-old were randomly distributed into two groups. AROM and neuromotor development with Alberta Infant Motor Scale (AIMS) were measured. The evaluation was performed by an examiner, blinded to the randomization of the subjects. A pediatric integrative manual therapy (PIMT) group received 10-sessions involving manual therapy and a caregiver education program. Manual therapy was addressed to the upper cervical spine to mobilize the occiput, atlas and axis. The caregiver educational program consisted in exercises to reduce the positional preference and to stimulate motor development. The control group received the caregiver education program exclusively. To compare intervention effectiveness across the groups, improvement indexes of AROM and AIMS were calculated using the difference of the final measurement values minus the baseline measurement values. If the distribution was normal, the improvement indexes were compared using the Student t-test for independent samples; if not, the Mann-Whitney U test was used. The effect size of the interventions was calculated using Cohen's d. RESULTS: All randomized subjects were analysed. After the intervention, the PIMT group showed a significantly higher increase in rotation (29.68 ± 18.41°) than the control group (6.13 ± 17.69°) (p = 0.001). Both groups improved the neuromotor development but no statistically significant differences were found. No harm was reported during the study. CONCLUSION: The PIMT intervention program was more effective in increasing AROM than using only a caregiver education program. The study has been retrospectively registered at clinicaltrials.gov, with identification number NCT03659032 . Registration date: September 1, 2018.

Adaptation and transcultural translation into Spanish of the Identification of Functional Ankle Instability questionnaire.

BACKGROUND: Functional ankle instability can hinder the ability to work and perform leisure tasks. Some questionnaires have been used to identify subjects with ankle instability. The English version of the identification functional ankle instability (IdFAI) questionnaire has been broadly used, but there is not a cross-cultural adaptation into Spanish. OBJECTIVE: The purpose of this study was to cross-culturally adapt the Identification of Functional Ankle Instability questionnaire to a Spanish speaking population from Spain. DESIGN: Cross-sectional study. METHODS: One hundred and four patients with history of lateral ankle sprain completed the Spanish version of this questionnaire and the Spanish version of the Cumberland Ankle Instability Tool. The psychometric properties were measured for structural validity, internal consistency, convergent validity, test-retest reliability, standard error of each measurement, ceiling effect and floor effect. RESULTS: The Spanish version of the Identification of Functional Ankle Instability questionnaire had a strong correlation with the Cumberland Ankle Instability Tool (rho = -0.717) with excellent reliability (ICC = 0.9) and internal consistency (Cronbach's α = 0.9). No ceiling or floor effects were detected. CONCLUSION: The results of the present study show that the Spanish version of the Identification of Functional Ankle Instability questionnaire is a valid and reliable measurement tool that can be use in a Spanish population from Spain with functional ankle instability for clinical and research purposes.

Interrater and Intrarater Reliability of Cranial Anthropometric Measurements in Infants with Positional Plagiocephaly.

(1) Background: anthropometric measurements with calipers are used to objectify cranial asymmetry in positional plagiocephaly but there is controversy regarding the reliability of different methodologies. Purpose: to analyze the interrater and intrarater reliability of direct anthropometric measurements with caliper on defined craniofacial references in infants with positional plagiocephaly. (2) Methods: 62 subjects (<28 weeks), with a difference of at least 5 mm between cranial diagonal diameters. Maximal cranial circumference, length and width and diagonal cranial diameters were measured. Intrarater (2 measurements) and interrater (2 raters) reliability was analyzed. (3) Results: intra- and interrater reliability of the maximal cranial length and width and right cranial diagonal was excellent: intraclass correlation coefficient (ICC) > 0.9. Intrarater and interrater reliability for the left cranial diagonal was excellent: ICC > 0.9 and difference in agreement in the Bland-Altman plot 0.0 mm, respectively. Intrarater and interrater reliability for the maximal cranial circumference was good: differences in agreement in Bland-Altman plots: intra: -0.03 cm; inter: -0.12 cm. (4) Conclusions: anthropometric measurements in a sample of infants with moderate positional plagiocephaly have shown excellent intra- and interrater reliability for maximal cranial length, maximal cranial width, and right and left cranial diagonals, and good intra- and interrater reliability in maximal cranial circumference measurement.

Multiscale Characterization of Embryonic Long Bone Mineralization in Mice.

Long bone mineralization occurs through endochondral ossification, where a cartilage template mineralizes into bone-like tissue with a hierarchical organization from the whole bone-scale down to sub-nano scale. Whereas this process has been extensively studied at the larger length scales, it remains unexplored at some of the smaller length scales. In this study, the changes in morphology, composition, and structure during embryonic mineralization of murine humeri are investigated using a range of high-resolution synchrotron-based imaging techniques at several length scales. With micro- and nanometer spatial resolution, the deposition of elements and the shaping of mineral platelets are followed. Rapid mineralization of the humeri occurs over approximately four days, where mineral to matrix ratio and calcium content in the most mineralized zone reach adult values shortly before birth. Interestingly, zinc is consistently found to be localized at the sites of ongoing new mineralization. The mineral platelets in the most recently mineralized regions are thicker, longer, narrower, and less aligned compared to those further into the mineralized region. In summary, this study demonstrates a specific spatial distribution of zinc, with highest concentration where new mineral is being deposited and that the newly formed mineral platelets undergo slight reshaping and reorganization during embryonic development.

Spin cascade and doming in ferric hemes: Femtosecond X-ray absorption and X-ray emission studies.

The structure-function relationship is at the heart of biology, and major protein deformations are correlated to specific functions. For ferrous heme proteins, doming is associated with the respiratory function in hemoglobin and myoglobins. Cytochrome c (Cyt c) has evolved to become an important electron-transfer protein in humans. In its ferrous form, it undergoes ligand release and doming upon photoexcitation, but its ferric form does not release the distal ligand, while the return to the ground state has been attributed to thermal relaxation. Here, by combining femtosecond Fe Kα and Kß X-ray emission spectroscopy (XES) with Fe K-edge X-ray absorption near-edge structure (XANES), we demonstrate that the photocycle of ferric Cyt c is entirely due to a cascade among excited spin states of the iron ion, causing the ferric heme to undergo doming, which we identify. We also argue that this pattern is common to a wide diversity of ferric heme proteins, raising the question of the biological relevance of doming in such proteins.