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.

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.

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.

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.

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.

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.

Preliminary Aquatic Physical Therapy Core Sets for Children and Youth With Neurological Disorders: A Consensus Process.

PURPOSE: To report on the preliminary aquatic physical therapy core sets for children and youth with neurological disorders using the International Classification of Functioning, Disability and Health-children and youth version. METHODS: A formal and structured consensus process was developed, integrating the findings of preparatory studies: a systematic literature review, expert survey with 69 participants, and a qualitative study with 43 participants. RESULTS: Five preliminary aquatic physical therapy core sets were described: a Comprehensive Core Set (64 categories); a Common Brief (13 categories); and 3 age-specific Core Sets: infant (below 6 years, 18 categories), school-age (from 6 to <14 years, 22 categories), and youth (from 14 to 18 years, 19 categories). CONCLUSIONS: Consensus among aquatic physical therapists' expert opinions identified the relevant intervention categories available when treating children and youth with neurological disorders. This list of intervention categories can be used in practice, research, education, and health administration.

Prevalence and Factors Associated With Injuries in Elite Spanish Volleyball.

CONTEXT: Prevalence studies have been carried out widely on elite volleyball players. However, the extent to which specific prevention strategies are used and the influence of the sport equipment on the occurrence of injuries have been sparsely investigated. OBJECTIVE: To describe the prevalence of injuries sustained during 1 season in elite Spanish volleyball leagues and to investigate the association of injuries with factors such as player court position, injury mechanism, type of shoes used when playing, or participation in prevention activities. DESIGN: Descriptive cross-sectional epidemiology study: observational study. SETTING: European elite professional volleyball. PARTICIPANTS: Professional volleyball players from the elite Spanish volleyball league. MAIN OUTCOME MEASURES: A self-report questionnaire assessed the presence of injury during a volleyball season. Questions included the type of injury, its anatomic location, participation in prevention strategies, shoe type, the injury mechanism, the season period, the period of leave, and the treatment received. RESULTS: In total, 490 players (71.2% response rate) completed and returned the questionnaire. The injury prevalence was 66.9%, and the average of injuries per player was 0.94 (0.85) (range: 0-4). Most Spanish elite volleyball players participated in prevention programs during the season (90.3%) and played volleyball with low-top shoes (83.6%), but these factors were not associated with the prevalence of injuries (P > .05). The anatomic regions with the most injuries were the ankle, knee, and shoulder; the most common types of injury were sprains, tendinopathies, and strains, usually occurring during blocking and attack actions during the in-season period. CONCLUSIONS: Despite most elite volleyball players participating in prevention programs, the results reveal a high injury prevalence. Further prospective research on the effectiveness of prevention strategies in elite volleyball is needed.

Multimodal manual therapy vs. pharmacological care for management of tension type headache: A meta-analysis of randomized trials.

BACKGROUND: Manual therapies are generally requested by patients with tension type headache. OBJECTIVE: To compare the efficacy of multimodal manual therapy vs. pharmacological care for the management of tension type headache pain by conducting a meta-analysis of randomized controlled trials. METHODS: PubMed, MEDLINE, EMBASE, AMED, CINAHL, EBSCO, Cochrane Database of Systematic Reviews, Cochrane Collaboration Trials Register, PEDro and SCOPUS were searched from their inception until June 2014. All randomized controlled trials comparing any manual therapy vs. medication care for treating tension type headache adults were included. Data were extracted and methodological quality assessed independently by two reviewers. We pooled headache frequency as the main outcome and also intensity and duration. The weighted mean difference between manual therapy and pharmacological care was used to determine effect sizes. RESULTS: Five randomized controlled trials met our inclusion criteria and were included in the meta-analysis. Pooled analyses found that manual therapies were more effective than pharmacological care in reducing frequency (weighted mean difference -0.8036, 95% confidence interval -1.66 to -0.44; three trials), intensity (weighted mean difference -0.5974, 95% confidence interval -0.8875 to -0.3073; five trials) and duration (weighted mean difference -0.5558, 95% confidence interval -0.9124 to -0.1992; three trials) of the headache immediately after treatment. No differences were found at longer follow-up for headache intensity (weighted mean difference -0.3498, 95% confidence interval -1.106 to 0.407; three trials). CONCLUSION: Manual therapies were associated with moderate effectiveness at short term, but similar effectiveness at longer follow-up for reducing headache frequency, intensity and duration in tension type headache than pharmacological medical drug care. However, due to the heterogeneity of the interventions, these results should be considered with caution at this stage.

Evaluation of the psychometric properties of the Spanish version of the Denver Developmental Screening Test II.

UNLABELLED: The objective of this study was to examine the psychometric properties of the Spanish version of the Denver Developmental Screening Test II in a population of Spanish children. Two hundred children ranging from 9 month to 6 years were grouped into two samples (healthy/with psychomotor delay) and screened in order to check whether they suffered from psychomotor delay. Children from three Early Intervention Centres and three schools participated in this study. Criterion validity was calculated by the method of extreme groups, comparing healthy children to those with development delay. Interobserver and intraobserver reliability were calculated using Cohen Kappa coefficient, and internal consistency was calculated via the Kuder-Richardson coefficient. The scale demonstrated 89% sensitivity, 92% specificity, a positive predicted value of 91% and a negative predicted value of 89%, whereas the positive and negative likelihood ratio was 11.12 and 0.12, respectively. Intraobserver reliability ranged from 0.662 to 1, and interobserver reliability ranged from 0.886 to 1. The Kuder-Richardson coefficient values ranged from 87.5 to 97.6%. CONCLUSION: The Spanish version of the Denver Developmental Screening Test II was found to have a good criterion validity, reliability and internal consistency and is a suitable screening test for use in a population of Spanish children.

Effects of spray and stretch on postneedling soreness and sensitivity after dry needling of a latent myofascial trigger point.

OBJECTIVES: To investigate (1) the effect of spray and stretch versus control on reducing postneedling soreness of 1 latent myofascial trigger point (MTrP) and (2) whether higher levels of psychological distress are associated with increased postneedling pain intensity. DESIGN: A 72-hour follow-up, single-blind randomized controlled trial. SETTING: University community. PARTICIPANTS: Healthy volunteers (N=70; 40 men, 30 women) aged 18 to 36 years (mean age, 21±4y) with latent MTrP in 1 upper trapezius muscle. INTERVENTION: All subjects received a dry needling application over the upper trapezius muscle. Then, participants were randomly divided into 2 groups: an intervention group, which received spray and stretch over the needled trapezius muscle, and a control group, which did not receive any intervention. MAIN OUTCOME MEASURES: Visual analog scale (at postneedling, posttreatment, and 6, 12, 24, 48, and 72h after needling), pressure pain threshold (at preneedling, postneedling, and 24 and 48h after needling). Psychological distress was evaluated by using the Symptom Checklist-90-Revised. RESULTS: Repeated-measures analysis of variance demonstrated a significant interaction between group and time (F3,204.8=3.19; P<.05; ηp(2)=.04) for changes in postneedling soreness. Between-group differences were significant only immediately after intervention (P=.002), and there were no differences found between groups after 6 hours of the intervention (P>.05). Repeated measures of covariance showed that none of the psychological covariates affected these results. Somatization, anxiety, interpersonal sensitivity, and hostility were significantly correlated (P<.05) with postneedling pain intensity. Repeated-measures analysis of variance did not show a significant effect of spray and stretch on mechanical hyperalgesia (F2.6,175=1.9; P=.131; ηp(2)=.02). CONCLUSIONS: The spray and stretch had a short-term (<6h) effect in reducing postneedling soreness of a latent MTrP. Pressure pain threshold did not significantly change after spray and stretch. Psychological factors are related to postneedling pain.

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.

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.

Ultrafast Two-Color X-Ray Emission Spectroscopy Reveals Excited State Landscape in a Base Metal Dyad.

Effective photoinduced charge transfer makes molecular bimetallic assemblies attractive for applications as active light-induced proton reduction systems. Developing competitive base metal dyads is mandatory for a more sustainable future. However, the electron transfer mechanisms from the photosensitizer to the proton reduction catalyst in base metal dyads remain so far unexplored. A Fe─Co dyad that exhibits photocatalytic H2 production activity is studied using femtosecond X-ray emission spectroscopy, complemented by ultrafast optical spectroscopy and theoretical time-dependent DFT calculations, to understand the electronic and structural dynamics after photoexcitation and during the subsequent charge transfer process from the FeII photosensitizer to the cobaloxime catalyst. This novel approach enables the simultaneous measurement of the transient X-ray emission at the iron and cobalt K-edges in a two-color experiment. With this methodology, the excited state dynamics are correlated to the electron transfer processes, and evidence of the Fe→Co electron transfer as an initial step of proton reduction activity is unraveled.

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.

Effects of burst-type transcutaneous electrical nerve stimulation on cervical range of motion and latent myofascial trigger point pain sensitivity.

OBJECTIVE: To assess the effects of a burst application of transcutaneous electrical nerve stimulation (TENS) on cervical range of motion and pressure point sensitivity of latent myofascial trigger points (MTrPs). DESIGN: A single-session, single-blind randomized trial. SETTING: General community rehabilitation clinic. PARTICIPANTS: Individuals (N = 76; 45 men, 31 women) aged 18 to 41 years (mean ± SD, 23 ± 4y) with latent MTrPs in 1 upper trapezius muscle. INTERVENTIONS: Subjects were randomly divided into 2 groups: a TENS group that received a burst-type TENS (pulse width, 200 µs; frequency, 100 Hz; burst frequency, 2 Hz) stimulation over the upper trapezius for 10 minutes, and a placebo group that received a sham-TENS application over the upper trapezius also for 10 minutes. MAIN OUTCOME MEASURES: Referred pressure pain threshold (RPPT) over the MTrP and cervical range of motion in rotation were assessed before, and 1 and 5 minutes after the intervention by an assessor blinded to subjects' treatment. RESULTS: The analysis of covariance revealed a significant group × time interaction (P < .001) for RPPT: the TENS group exhibited a greater increase compared with the control group; however, between-group differences were small at 1 minute (0.3 kg/cm²; 95% confidence interval [CI], 0.1-0.4) and at 5 minutes (0.6 kg/cm²; 95% CI, 0.3-0.8) after treatment. A significant group × time interaction (P=.01) was also found for cervical rotation in favor of the TENS group. Between-group differences were also small at 1 minute (2.0°; 95% CI, 1.0-2.8) and at 5 minutes (2.7°; 95% CI, 1.7-3.8) after treatment. CONCLUSIONS: A 10-minute application of burst-type TENS increases in a small but statistically significant manner the RPPT over upper trapezius latent MTrPs and the ipsilateral cervical range of motion.