The laser pump X-ray probe system at LISA P08 PETRA†III.

Understanding and controlling the structure and function of liquid interfaces is a constant challenge in biology, nanoscience and nanotechnology, with applications ranging from molecular electronics to controlled drug release. X-ray reflectivity and grazing incidence diffraction provide invaluable probes for studying the atomic scale structure at liquid-air interfaces. The new time-resolved laser system at the LISA liquid diffractometer situated at beamline P08 at the PETRA III synchrotron radiation source in Hamburg provides a laser pump with X-ray probe. The femtosecond laser combined with the LISA diffractometer allows unique opportunities to investigate photo-induced structural changes at liquid interfaces on the pico- and nanosecond time scales with pump-probe techniques. A time resolution of 38 ps has been achieved and verified with Bi. First experiments include laser-induced effects on salt solutions and liquid mercury surfaces with static and varied time scales measurements showing the proof of concept for investigations at liquid surfaces.

Feasibility of a clinic-based, multicomponent hydroxyurea adherence intervention for adolescents and young adults with sickle cell disease.

Despite the effectiveness of hydroxyurea, adherence remains low for adolescents and young adults (AYA) living with sickle cell disease (SCD). This study evaluated the feasibility, acceptability, and initial efficacy of a clinic-based, multicomponent (e.g., storytelling, problem solving) intervention with 20 AYA living with SCD. Results found that adherence significantly improved from intervention to follow-up 1 [t(19) = -2.213, p = .039]. AYA also were generally satisfied with the intervention. These findings, although promising, should be replicated on a larger scale.

Attitudes, Beliefs, and Intention to Receive a COVID-19 Vaccine for Pediatric Patients With Sickle Cell Disease.

Sickle cell disease (SCD), which occurs primarily in individuals of African descent, has been identified as a preexisting health condition for COVID-19 with higher rates of hospitalization, intensive care unit admissions, and death. National data indicate Black individuals have higher rates of vaccine hesitancy and lower COVID-19 vaccination rates. Understanding the key predictors of intention to receive a COVID-19 vaccine is essential as intention is strongly associated with vaccination behavior. This multisite study examined attitudes, beliefs, intentions to receive COVID-19 vaccines, and educational preferences among adolescents, young adults, and caregivers of children living with SCD. Participants completed an online survey between July 2021 and March 2022. Multivariate logistic regression was used to examine the association between participant age and COVID-19 vaccine attitudes, beliefs, and vaccine intentions. Of the 200 participants, 65.1% of adolescents, 62.5% of young adults, and 48.4% of caregivers intended to receive a COVID-19 vaccine for themselves or their child. Perception that the vaccine was safe was statistically significant and associated with patient and caregiver intention to receive the COVID-19 vaccine for themselves or their child. Participant age was also statistically significant and associated with the intent to get a booster for patients. Study findings highlight key concerns and influencers identified by patients with SCD and their caregivers that are essential for framing COVID-19 vaccine education during clinical encounters. Study results can also inform the design of messaging campaigns for the broader pediatric SCD population and targeted interventions for SCD subpopulations (eg, adolescents, caregivers).

Closing the loop: autonomous experiments enabled by machine-learning-based online data analysis in synchrotron beamline environments.

Recently, there has been significant interest in applying machine-learning (ML) techniques to the automated analysis of X-ray scattering experiments, due to the increasing speed and size at which datasets are generated. ML-based analysis presents an important opportunity to establish a closed-loop feedback system, enabling monitoring and real-time decision-making based on online data analysis. In this study, the incorporation of a combined one-dimensional convolutional neural network (CNN) and multilayer perceptron that is trained to extract physical thin-film parameters (thickness, density, roughness) and capable of taking into account prior knowledge is described. ML-based online analysis results are processed in a closed-loop workflow for X-ray reflectometry (XRR), using the growth of organic thin films as an example. Our focus lies on the beamline integration of ML-based online data analysis and closed-loop feedback. Our data demonstrate the accuracy and robustness of ML methods for analyzing XRR curves and Bragg reflections and its autonomous control over a vacuum deposition setup.

Ionic Liquid-Induced Assembly of DNA at Air-Water Interface.

DNA nanotechnology is the future of many products in the pharmaceutical and cosmetic industries. Self-assembly of this negatively charged biopolymer at surfaces and interfaces is an essential step to elaborate its field of applications. In this study, the ionic liquid (IL) monolayer-assisted self-assembly of DNA macromolecules at the air-water interface has been closely monitored by employing various quantitative techniques, namely, surface pressure-area (π-A) isotherms, surface potential, interfacial rheology, and X-ray reflectivity (XRR). The π-A isotherms reveal that the IL 1,3-didecyl 3-methyl imidazolium chloride induces DNA self-assembly at the interface, leading to a thick viscoelastic film. The interfacial rheology exhibits a notable rise in the viscoelastic modulus as the surface pressure increases. The values of storage and loss moduli measured as a function of strain frequency suggest a relaxation frequency that depends on the length of the macromolecule. The XRR measurements indicate a considerable increase in DNA layer thickness at the elevated surface pressures depending on the number of base pairs of the DNA. The results are considered in terms of the electrostatic and hydrophobic interactions, allowing a quantitative conclusion about the arrangement of DNA strands underneath the monolayer of the ILs at the air-water interface.

X-ray reflectivity from curved surfaces as illustrated by a graphene layer on molten copper.

The X-ray reflectivity technique can provide out-of-plane electron-density profiles of surfaces, interfaces, and thin films, with atomic resolution accuracy. While current methodologies require high surface flatness, this becomes challenging for naturally curved surfaces, particularly for liquid metals, due to the very high surface tension. Here, the development of X-ray reflectivity measurements with beam sizes of a few tens of micrometres on highly curved liquid surfaces using a synchrotron diffractometer equipped with a double crystal beam deflector is presented. The proposed and developed method, which uses a standard reflectivity θ-2θ scan, is successfully applied to study in situ the bare surface of molten copper and molten copper covered by a graphene layer grown in situ by chemical vapor deposition. It was found that the roughness of the bare liquid surface of copper at 1400 K is 1.25 ± 0.10 Å, while the graphene layer is separated from the liquid surface by a distance of 1.55 ± 0.08 Šand has a roughness of 1.26 ± 0.09 Å.

A systematic review of randomized controlled trials examining workplace wellness interventions.

BACKGROUND: One of the influencing factors associated with weight gain is overeating as a maladaptive coping strategy to process or avoid the emotional impact of psychological stress. Psychological stress is chronically and pervasively associated with stress stemming from the workplace environment. Workplace wellness interventions have a unique opportunity to change environmental factors impacting psychological stress, which can improve individual food choice and weight management efforts. AIM: To synthesize evidence from randomized controlled trials on workplace wellness interventions that impact employee psychological stress and food choice or weight management. METHODS: A systematic review was completed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Selected studies were limited to English-language articles exploring randomized interventions at workplaces among adult employees and included measurements of psychometric stress and food choice (qualitative or quantitative) or biometric weight management. From the search, 10 studies were included in the final review. RESULTS: Results were inconsistent across studies. There was no observable association between psychological stress reduction and food choice or weight management. Mid-length interventions (ranging from 6 to 9 months) had more consistent associations between intervention program implementation, reduced psychological stress, and improved food choice or weight management. CONCLUSIONS: The studies examining employee food choices and weight management efforts remained very heterogeneous, indicating that more research is needed in this specific area of employee wellness program planning and measurement. Consistent research methodology and assessment tools are needed to measure dietary intake.

A derivation error that affects carbon balance models exists in the current implementation of the modified Arrhenius function.

Understanding biological temperature responses is crucial to predicting global carbon fluxes. The current approach to modelling temperature responses of photosynthetic capacity in large scale modelling efforts uses a modified Arrhenius equation. We rederived the modified Arrhenius equation from the source publication from 1942 and uncovered a missing term that was dropped by 2002. We compare fitted temperature response parameters between the correct and incorrect derivation of the modified Arrhenius equation. We find that most parameters are minimally affected, though activation energy is impacted quite substantially. We then scaled the impact of these small errors to whole plant carbon balance and found that the impact of the rederivation of the modified Arrhenius equation on modelled daily carbon gain causes a meaningful deviation of c. 18% day-1 . This suggests that the error in the derivation of the modified Arrhenius equation has impacted the accuracy of predictions of carbon fluxes at larger scales since > 40% of Earth System Models contain the erroneous derivation. We recommend that the derivation error be corrected in modelling efforts moving forward.

Synergistic and Competitive Adsorption of Hydrophilic Nanoparticles and Oil-Soluble Surfactants at the Oil-Water Interface.

Fundamental insights into the interplay and self-assembly of nanoparticles and surface-active agents at the liquid-liquid interface play a pivotal role in understanding the ubiquitous colloidal systems present in our natural surroundings, including foods and aquatic life, and in the industry for emulsion stabilization, drug delivery, or enhanced oil recovery. Moreover, well-controlled model systems for mixed interfacial adsorption of nanoparticles and surfactants allow unprecedented insights into nonideal or contaminated particle-stabilized emulsions. Here, we investigate such a model system composed of hydrophilic, negatively, and positively charged silica nanoparticles and the oil-soluble cationic lipid octadecyl amine with in situ synchrotron-based X-ray reflectometry, which is analyzed and discussed jointly with dynamic interfacial tensiometry. Our results indicate that negatively charged silica nanoparticles only adsorb if the oil-water interface is covered with the positively charged lipid, indicating synergistic adsorption. Conversely, the positively charged nanoparticles readily adsorb on their own, but compete with octadecyl amine and reversibly desorb with increasing concentrations of the lipid. These results further indicate that with competitive adsorption, an electrostatic exclusion zone exists around the adsorbed particles. This prevents the adsorption of lipid molecules in this area, leading to a decreased surface excess concentration of surfactants and unexpectedly high interfacial tension.

Association between dairy product intake and body composition among South Asian adults from the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study.

South Asians, who are at a disproportionately greater risk of atherosclerotic CVD (ASCVD), represent a rapidly growing population in the USA. The relationship between dairy products, a major component of South Asian diets, and body composition - an established risk factor for ASCVD, is unclear. The aim of the present study was to examine associations between dairy intake and multiple measures of body composition (BMI, waist and hip circumference, waist:hip ratio, abdominal lean mass, subcutaneous, visceral, and intermuscular fat areas) among South Asian adults in the USA. A baseline analysis was conducted using existing data from the Mediators of Atherosclerosis in South Asians Living in America cohort. In women, the highest (>1·9 servings/d) v. lowest (<1 serving/d) tertile of dairy intake was associated with 53 % lower odds of a waist circumference >80 cm (95 % CI 0·25, 0·89, Pfor trend<0·05). No associations were observed between dairy intake and measures of body composition. However, >3 servings of low-fat yogurt/week was associated with a 9·9 cm2 lower visceral fat area (95 % CI -19·07, -0·72, P<0·05) and 2·3 cm2 lower intermuscular fat area (95 % CI -3·76, -0·79, P<0·05) as compared with those with three servings/week. Milk and cheese were not associated with body composition measures. These analyses suggest that higher consumption of low-fat yogurt is associated with lower visceral and intermuscular fat in the whole sample, and women with higher dairy intake have lower waist circumference. Our study supports dietary incorporation of dairy products, and recognises the utility of multidimensional measures of central adiposity.

Comment on "Bi-layering at ionic liquid surfaces: a sum - frequency generation vibrational spectroscopy - and molecular dynamics simulation-based study" by T. Iwahashi, T. Ishiyama, Y. Sakai, A. Morita, D. Kim and Y. Ouchi, Phys. Chem. Chem. Phys., 2020, 22, 12565.

This Comment raises several questions concerning the surface structure concluded in the paper referenced in the title. Specifically, that paper ignores previous experiments and simulations which demonstrate for the same ionic liquids depth-decaying, multilayered surface-normal density profiles rather than the claimed molecular mono- or bi-layers. We demonstrate that the claimed structure does not reproduce the measured X-ray reflectivity, which probes directly the surface-normal density profile. The measured reflectivities are found, however, to be well-reproduced by a multilayered density model. These results, and previous experimental and simulation results, cast severe doubt on the validity of the surface structure claimed in the paper referenced in the title.

Surface structure evolution in a homologous series of ionic liquids.

Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation's alkyl chain length [Formula: see text] from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid-air interface for [Formula: see text], using angstrom-resolution X-ray methods. For [Formula: see text], a typical "simple liquid" monotonic surface-normal electron density profile [Formula: see text] is obtained, like those of water and organic solvents. For [Formula: see text], increasingly more pronounced nanoscale self-segregation of the molecules' charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear [Formula: see text] dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For [Formula: see text], a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk-surface structure relations.

Nucleation and Growth of PbBrF Crystals at the Liquid Mercury-Electrolyte Interface Studied by Operando X-ray Scattering.

Detailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above -0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing supersaturation near the interface, caused by the potential-dependent Pb2+ deamalgamation, which changes from a slow reaction-controlled process to a fast transport-controlled process in this range of overpotentials. In addition, growth on the liquid substrate is found to involve complex micromechanical effects, such as crystal reorientation and film breakup during dissolution.

X-ray reflectivity from curved liquid interfaces.

X-ray reflectivity studies of the structure of liquid-vapour and liquid-liquid interfaces at modern sources, such as free-electron lasers, are currently impeded by the lack of dedicated liquid surface diffractometers. It is shown that this obstacle can be overcome by an alternative experimental approach that uses the natural curvature of a liquid drop for variation of the angle of incidence. Two modes of operation are shown: (i) sequential reflectivity measurements by a nanometre beam and (ii) parallel acquisition of large ranges of a reflectivity curve by micrometre beams. The feasibility of the two methods is demonstrated by studies of the Hg/vapour, H2O/vapour and Hg/0.1 M NaF interface. The obtained reflectivity curves match the data obtained by conventional techniques up to 5αc in micro-beam mode and up to 35αc in nano-beam mode, allowing observation of the Hg layering peak.

Photoswitchable Glycolipid Mimetics: Synthesis and Photochromic Properties of Glycoazobenzene Amphiphiles.

Glycolipids as constituents of cell membranes play an important role in cell membrane functioning. To enable the structural modification of membranes on demand, embedding of photosensitive glycolipid mimetics was envisioned and novel amphiphilic glycolipid mimetics comprising a photoswitchable azobenzene unit were synthesized. In this study, the photochromic properties of these glycolipid mimetics were analyzed by means of UV/Vis spectroscopy and reversible photoswitching. The glycolipids were based on a racemic glycerolipid derivative to be comparable in DPPC (dipalmitoylphosphatidylcholine) phospholipid membrane monolayers. Carbohydrate head groups were altered between a ß-glucoside and a ß-lactosyl unit, as well as acyl chain lengths between C12 and C16, resulting in altered photoswitching. Langmuir isotherms showed that photoswitching of Langmuir films comprising the synthetic photosensitive glycoamphiphiles was successful.

Correction: Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2].

Correction for 'Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2]-' by Julian Mars et al., Phys. Chem. Chem. Phys., 2017, 19, 26651-26661.

Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2].

Surface induced smectic order was found for the ionic liquid 1-methyl-3-docosylimidazolium bis(trifluoromethlysulfonyl)imide by X-ray reflectivity and grazing incidence scattering experiments. Near the free liquid surface, an ordered structure of alternating layers composed of polar and non-polar moieties is observed. This leads to an oscillatory interfacial profile perpendicular to the liquid surface with a periodicity of 3.7 nm. Small angle X-ray scattering and polarized light microscopy measurements suggest that the observed surface structure is related to fluctuations into a metastable liquid crystalline SmA2 phase that was found by supercooling the bulk liquid. The observed surface ordering persists up to 157 °C, i.e. more than 88 K above the bulk melting temperature of 68.1 °C. Close to the bulk melting point, we find a thickness of the ordered layer of L = 30 nm. The dependency of L(τ) = Λ ln(τ/τ1) vs. reduced temperature τ follows a logarithmic growth law. In agreement with theory, the pre-factor Λ is governed by the correlation length of the isotropic bulk phase.

Cross-cultural comparison of long-term care in the United States and Finland: Research done through a short-term study-abroad experience.

In May 2014, a short-term study-abroad experience was conducted in Finland through a course offered at Indiana State University (ISU). Students and faculty from ISU and Eastern Illinois University participated in the experience, which was created to facilitate a cross-cultural comparison of long-term-care settings in the United States and Finland. With its outstanding system of caring for the health and social needs of its aging populace, Finland is a logical model to examine when considering ways to improve the quality of life for older adults who require care in the United States . Those participating in the course visited a series of long-term-care facilities in the region surrounding Terre Haute, Indiana, then travelled to Lappeenranta, Finland to visit parallel sites. Through limited-participation observation and semistructured interviews, similarities and differences in experiences, educations, and policies affecting long-term care workers in the United States and Finland were identified and are described here.