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In megabar shock waves, materials compress and undergo a phase transition to a dense charged-particle system that is dominated by strong correlations and quantum effects. This complex state, known as warm dense matter, exists in planetary interiors and many laboratory experiments (for example, during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions). Here, we apply record peak brightness X-rays at the Linac Coherent Light Source to resolve ionic interactions at atomic (ångström) scale lengths and to determine their physical properties. Our in situ measurements characterize the compressed lattice and resolve the transition to warm dense matter, demonstrating that short-range repulsion between ions must be accounted for to obtain accurate structure factor and equation of state data. In addition, the unique properties of the X-ray laser provide plasmon spectra that yield the temperature and density with unprecedented precision at micrometre-scale resolution in dynamic compression experiments. Warm dense matter (WDM), which falls in the category between plasmas and condensed matter, is expected to exist in planetary interiors. Now, researchers use an X-ray laser to observe the transition to WDM.

Background As an indigestible component of human breast milk, Human Milk Oligosaccharides (HMOs) play an important role as a substrate for the establishing microbiome of the newborn. They have further been shown to have beneficial effects on the immune system, lung and brain development. For preterm infants HMO composition of human breast milk may be of particular relevance since the establishment of a healthy microbiome is challenged by multiple disruptive factors associated with preterm birth, such as cesarean section, hospital environment and perinatal antibiotic exposure. In a previous study it has been proposed that maternal probiotic supplementation during late stages of pregnancy may change the HMO composition in human milk. However, there is currently no study on pregnancies which are threatened to preterm birth. Furthermore, HMO composition has not been investigated in association with clinically relevant outcomes of vulnerable infants including inflammation-mediated diseases such as sepsis, necrotizing enterocolitis (NEC) or chronic lung disease. Main body A randomized controlled intervention study (PROMO = probiotics for human milk oligosaccharides) has been designed to analyze changes in HMO composition of human breast milk after supplementation of probiotics ( Lactobacillus acidophilus , Bifidobacterium lactis and Bifidobacterium infantis ) in pregnancies at risk for preterm birth. The primary endpoint is HMO composition of 3-fucosyllactose and 3’-sialyllactose in expressed breast milk. We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. As secondary outcomes we will measure preterm infants’ clinical outcomes (preterm birth, sepsis, weight gain growth, gastrointestinal complications) and effects on microbiome composition in the rectovaginal tract of mothers at delivery and in the gut of term and preterm infants by sequencing at high genomic resolution. Therefore, we will longitudinally collect bio samples in the first 4 weeks after birth as well as in follow-up investigations at 3 months, one year, and five years of age. Conclusions We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. The PROMO study will gain insight into the microbiome-HMO interaction at the fetomaternal interface and its consequences for duration of pregnancy and outcome of infants.

Hydrogen, the simplest element in the universe, has a surprisingly complex phase diagram. Because of applications to planetary science, inertial confinement fusion and fundamental physics, its high-pressure properties have been the subject of intense study over the past two decades. While sophisticated static experiments have probed hydrogen’s structure at ever higher pressures, studies examining the higher-temperature regime using dynamic compression have mostly been limited to optical measurement techniques. Here we present spectrally resolved x-ray scattering measurements from plasmons in dynamically compressed deuterium. Combined with Compton scattering, and velocity interferometry to determine shock pressure and mass density, this allows us to extract ionization state as a function of compression. The onset of ionization occurs close in pressure to where density functional theory-molecular dynamics (DFT-MD) simulations show molecular dissociation, suggesting hydrogen transitions from a molecular and insulating fluid to a conducting state without passing through an intermediate atomic phase. High-pressure experiments play a critical role in understanding planetary interiors, but are notoriously difficult to carry out. Here, the authors demonstrate a laboratory platform for the controlled exploration of deuterium, with results that challenge existing models of ionization under compression.

Here, we report results of an experiment creating a transient, highly correlated carbon state using a combination of optical and x-ray lasers. Scattered x-rays reveal a highly ordered state with an electrostatic energy significantly exceeding the thermal energy of the ions. Strong Coulomb forces are predicted to induce nucleation into a crystalline ion structure within a few picoseconds. However, we observe no evidence of such phase transition after several tens of picoseconds but strong indications for an over-correlated fluid state. The experiment suggests a much slower nucleation and points to an intermediate glassy state where the ions are frozen close to their original positions in the fluid.

The unprecedented intensity of x-ray free-electron laser sources has enabled single-particle x-ray diffraction imaging (SPI) of various biological specimens in both two-dimensional projection and three dimensions (3D). The potential of studying protein dynamics in their native conditions, without crystallization or chemical staining, has encouraged researchers to aim for increasingly higher resolutions with this technique. The currently achievable resolution of SPI is limited to the sub-10 nanometer range, mainly due to background effects, such as instrumental noise and parasitic scattering from the carrier gas used for sample delivery. Recent theoretical studies have quantified the effects of x-ray pulse parameters, as well as the required number of diffraction patterns to achieve a certain resolution, in a 3D reconstruction, although the effects of detector noise and the random particle orientation in each diffraction snapshot were not taken into account. In this work, we show these shortcomings and address limitations on achievable image resolution imposed by the adaptive gain integrating pixel detector noise.

A pilot observational exposure study was performed to evaluate methods for collecting multimedia measurements (air, dust, food, urine) and activity patterns to assess potential exposures of young children to pesticides in their homes. Nine children (mean age=5 years) and their caregivers participated in this study, performed in the Duval County, Florida, in collaboration with the Centers for Disease Control and Prevention and the Duval County Health Department. For all nine children, the total time reported for sleeping and napping ranged from 9.5 to 14 h per day, indoor quiet time from 0 to 5.5 h per day, indoor active time from 0.75 to 5.5 h per day, outdoor quiet time from 0 to 1.5 h per day, and outdoor active time from 0.5 to 6.5 h per day. Each home had one to three pesticide products present, with aerosols being most common. Pesticide inventories, however, were not useful for predicting pesticide levels in the home. Synthetic pyrethroids were the most frequently identified active ingredients in the products present in each home. Fifteen pesticide active ingredients were measured in the application area wipes (not detected (ND) to 580 ng/cm 2 ), 13 in the play area wipes (ND-117 ng/cm 2 ), and 14 in the indoor air samples (ND-378 ng/m 3 ) and the socks (ND-1000 ng/cm 2 ). Cis -permethrin, trans -permethrin, and cypermethrin were measured in all nine homes. Chlorpyrifos was measured in all nine homes even though it was not reported used by the participants. All urine samples contained measurable concentrations of 3-phenoxybenzoic acid (3-PBA). The median 3-PBA urinary concentration for the nine children was 2.2  μ g/l. A wide variety of pesticide active ingredients were measured in these nine homes at median concentrations that were often higher than reported previously in similar studies. These data highlight the need for additional observational studies in regions where pesticides are used in order to understand the factors that affect young children's exposures and the education/mitigation strategies that can be used to reduce children's exposures.

Children are exposed to a wide variety of pesticides originating from both outdoor and indoor sources. Several studies were conducted or funded by the EPA over the past decade to investigate children’s exposure to organophosphate and pyrethroid pesticides and the factors that impact their exposures. Urinary metabolite concentration measurements from these studies are consolidated here to identify trends, spatial and temporal patterns, and areas where further research is required. Namely, concentrations of the metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol or TCPy), diazinon (2-isopropyl-6-methyl-4-pyrimidinol or IMP), and permethrin (3-phenoxybenzoic acid or 3-PBA) are presented. Information on the kinetic parameters describing absorption and elimination in humans is also presented to aid in interpretation. Metabolite concentrations varied more dramatically across studies for 3-PBA and IMP than for TCPy, with TCPy concentrations about an order of magnitude higher than the 3-PBA concentrations. Temporal variability was high for all metabolites with urinary 3-PBA concentrations slightly more consistent over time than the TCPy concentrations. Urinary biomarker levels provided only limited evidence of applications. The observed relationships between urinary metabolite levels and estimates of pesticide intake may be affected by differences in the contribution of each exposure route to total intake, which may vary with exposure intensity and across individuals.

We are developing a target platform that utilizes short-pulse (10 ps) generated hot electrons (∼200 keV) to isochorically heat solid density beryllium up to temperatures of several 10 eV. We use x-ray Thomson scattering to characterize the plasma conditions. X-rays from a Cl Ly-α line source at 2.96 keV are scattered off the plasma in forward direction where the inelastically scattered signal is sensitive to plasma oscillations. Besides Landau-damping the strong energy down-shifted plasmon signal is also broadened by electron-ion collisions which, in turn, allows to infer the collision rate and thus the conductivity in these plasmas. A precise knowledge of the collisionality in the parameter regime we are aiming at with these experiments is important to correctly model the conditions encountered during capsule implosions at the National Ignition Facility.

Measurement of the dynamic properties of hydrogen and helium under extreme pressures is a key to understanding the physics of planetary interiors. The inelastic scattering signal from statically compressed hydrogen inside diamond anvil cells at 2.8 GPa and 6.4 GPa was measured at the Diamond Light Source synchrotron facility in the UK. The first direct measurement of the local field correction to the Coulomb interactions in degenerate plasmas was obtained from spectral shifts in the scattering data and compared to predictions by the Utsumi-Ichimaru theory for degenerate electron liquids.

We estimated cumulative residential pesticide exposures for a group of nine young children (4–6 years) using three different methodologies developed by the US Environmental Protection Agency and compared the results with estimates derived from measured urinary metabolite concentrations. The Standard Operating Procedures (SOPs) for Residential Exposure Assessment are intended to provide a screening-level assessment to estimate exposure for regulatory purposes. Nonetheless, dermal exposure estimates were typically lower from the SOP (1–1300 nmol/day) than from SHEDS (5–19,000 nmol/day) or any of the four different approaches for estimating dermal exposure using the Draft Protocol for Measuring Children's Non-Occupational Exposure to Pesticides by all Relevant Pathways (Draft Protocol) (5–11,000 nmol/day). Indirect ingestion exposure estimates ranged from 0.02 to 21.5 nmol/day for the SOP, 0.5 to 188 nmol/day for SHEDS, and 0 to 3.38 nmol/day for the Draft Protocol. Estimates of total absorbed dose ranged from 3 to 37 nmol/day for the SOPs, 0.5 to 100 nmol/day for SHEDS, and 1 to 216 nmol/day for the Draft Protocol. The concentrations estimated using the Draft Protocol and SHEDS showed strong, positive relationships with the 3-phenoxybenzoic acid metabolite measured in the children's urine samples ( R 2 =0.90 for the Draft Protocol; R 2 =0.92 for SHEDS). Analysis of different approaches for estimating dermal exposure suggested that the approach assuming an even distribution of pesticide residue on the child's body was most reasonable. With all three methodologies providing reasonable estimates of exposure and dose, selection should depend on the available data and the objectives of the analysis. Further research would be useful to better understand how best to estimate dermal exposure for children and what exposure factors (e.g., activities, transfer coefficients, measurement techniques) are most relevant in making dermal exposure estimates.