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The effect of a dense plasma environment on the energy levels of an embedded ion is usually described in terms of the lowering of its continuum level. For strongly coupled plasmas, the phenomenon is intimately related to the equation of state; hence, an accurate treatment is crucial for most astrophysical and inertial-fusion applications, where the case of plasma mixtures is of particular interest. Here we present an experiment showing that the standard density-dependent analytical models are inadequate to describe solid-density plasmas at the temperatures studied, where the reduction of the binding energies for a given species is unaffected by the different plasma environment (ion density) in either the element or compounds of that species, and can be accurately estimated by calculations only involving the energy levels of an isolated neutral atom. The results have implications for the standard approaches to the equation of state calculations. The effect of dense plasma environment on the energy levels of an ion is usually described in terms of a lowering of its continuum level. Here the authors present an isochoric-heating experiment to measure and compare continuum lowering in single-species and mixture plasmas to provide insights for models.

DNA-based points accumulation for imaging in nanoscale topography (DNA-PAINT) is a powerful super-resolution microscopy method that can acquire high-fidelity images at nanometer resolution. It suffers, however, from high background and slow imaging speed, both of which can be attributed to the presence of unbound fluorophores in solution. Here we present two-color fluorogenic DNA-PAINT, which uses improved imager probe and docking strand designs to solve these problems. These self-quenching single-stranded DNA probes are conjugated with a fluorophore and quencher at the terminals, which permits an increase in fluorescence by up to 57-fold upon binding and unquenching. In addition, the engineering of base pair mismatches between the fluorogenic imager probes and docking strands allowed us to achieve both high fluorogenicity and the fast binding kinetics required for fast imaging. We demonstrate a 26-fold increase in imaging speed over regular DNA-PAINT and show that our new implementation enables three-dimensional super-resolution DNA-PAINT imaging without optical sectioning. Two-color fluorogenic DNA-PAINT introduces self-quenching, kinetics-optimized probe designs. This approach improves imaging speed 26-fold and eliminates the need for optical sectioning.

Experimental study of the interactions between intense X-rays and solid matter illustrate the generation of a solid-density plasma governed by electron–ion collisions; these results should inform future high-intensity X-ray experiments involving dense samples, such as X-ray diffractive imaging of biological samples, material science investigations, and the study of matter in extreme conditions. Solid progress for X-ray lasers With the advent of free-electron lasers, the high intensities previously only achievable with optical lasers can be produced at X-ray wavelengths. This opens new opportunities for theory and experiment. Here, Vinko et al . report the first detailed study of intense X-ray radiation interacting with solid density matter, carried out on the Linac Coherent Light Source free-electron laser at the SLAC National Accelerator Facility in California. They observe the generation of a solid-density plasma and establish that collisions have a pivotal role. The results should inform future high-intensity X-ray experiments involving dense samples, such as X-ray diffractive imaging of biological samples and materials science investigations. Matter with a high energy density (>10 5  joules per cm 3 ) is prevalent throughout the Universe, being present in all types of stars 1 and towards the centre of the giant planets 2 , 3 ; it is also relevant for inertial confinement fusion 4 . Its thermodynamic and transport properties are challenging to measure, requiring the creation of sufficiently long-lived samples at homogeneous temperatures and densities 5 , 6 . With the advent of the Linac Coherent Light Source (LCLS) X-ray laser 7 , high-intensity radiation (>10 17  watts per cm 2 , previously the domain of optical lasers) can be produced at X-ray wavelengths. The interaction of single atoms with such intense X-rays has recently been investigated 8 . An understanding of the contrasting case of intense X-ray interaction with dense systems is important from a fundamental viewpoint and for applications. Here we report the experimental creation of a solid-density plasma at temperatures in excess of 10 6 kelvin on inertial-confinement timescales using an X-ray free-electron laser. We discuss the pertinent physics of the intense X-ray–matter interactions, and illustrate the importance of electron–ion collisions. Detailed simulations of the interaction process conducted with a radiative-collisional code show good qualitative agreement with the experimental results. We obtain insights into the evolution of the charge state distribution of the system, the electron density and temperature, and the timescales of collisional processes. Our results should inform future high-intensity X-ray experiments involving dense samples, such as X-ray diffractive imaging of biological systems, material science investigations, and the study of matter in extreme conditions.

Background Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) have been and continue to be of great interest to researchers, given their use in flexible solar cells, wearable sensors, and electronic devices. Frictional properties of 2D HOIPs should be clearly understood to establish the manufacturing processes as well as the durability of the devices. Objective The aim of this study is to provide a fundamental understanding of the frictional properties of 2D HOIPs at the nanoscale. Methods The topography of 2D HOIPs with three different chain lengths and five different thicknesses were systematically examined with atomic force microscopy (AFM). The frictional properties of these films were also quantitatively assessed under various normal forces using friction force microscopy (FFM). Results From the AFM, it was found that the 2D HOIPs exhibited nanoscale surface roughness, presumably due to local disorder of the organic cations or deformation of the inorganic framework. In addition, FFM showed that the intrinsic friction of 2D HOIPs was significantly low. The friction force decreased as molecular chain length increased and thickness-dependent friction characteristics were clearly observed. Conclusions The trends were due to changes in mechanical properties, surface roughness, and suppression of puckering, but not due to changes in AFM tip adhesion.

The rate at which atoms and ions within a plasma are further ionized by collisions with the free electrons is a fundamental parameter that dictates the dynamics of plasma systems at intermediate and high densities. While collision rates are well known experimentally in a few dilute systems, similar measurements for nonideal plasmas at densities approaching or exceeding those of solids remain elusive. Here we describe a spectroscopic method to study collision rates in solid-density aluminium plasmas created and diagnosed using the Linac Coherent light Source free-electron X-ray laser, tuned to specific interaction pathways around the absorption edges of ionic charge states. We estimate the rate of collisional ionization in solid-density aluminium plasmas at temperatures ~30 eV to be several times higher than that predicted by standard semiempirical models. The electrons in a plasma can further ionize the ions when the two collide. Vinko et al . now study this ultrafast process in an unconventional plasma with a density similar to that of a solid, and show that the rate is several times higher than that predicted by standard theoretical models.

Background: Colorectal cancer (CRC) is a leading cause of death in the United States. Increased level of interleukin-8 (IL-8) and CXCR2 on tumours and in the tumour microenvironment has been associated with CRC growth, progression and recurrence in patients. Here, we aimed to evaluate the effects of tissue microenvironment-encoded IL-8 and CXCR2 on colon cancer progression and metastasis. Methods: A novel immunodeficient, skin-specific IL-8-expressing transgenic model was generated to evaluate colon cancer growth and metastasis. Syngeneic mouse colon cancer cells were grafted in CXCR2 knockout (KO) mice to study the contribution of CXCR2 in the microenvironment to cancer growth. Results: Elevated levels of IL-8 in the serum and tumour microenvironment profoundly enhanced the growth of human and mouse colon cancer cells with increased peri-tumoural angiogenesis, and also promoted the extravasation of the cancer cells into the lung and liver. The tumour growth was inhibited in CXCR2 KO mice with significantly reduced tumour angiogenesis and increased tumour necrosis. Conclusion: Increased expression of IL-8 in the tumour microenvironment enhanced colon cancer growth and metastasis. Moreover, the absence of its receptor CXCR2 in the tumour microenvironment prevented colon cancer cell growth. Together, our study demonstrates the critical roles of the tumour microenvironment-encoded IL-8/CXCR2 in colon cancer pathogenesis, validating the pathway as an important therapeutic target.

Background A large proportion of older adults suffer from chronic diseases. Health coaching is a promising intervention that enhances individuals’ health knowledge and supports changes in health behaviours. Even though health professionals usually conduct health coaching interventions, lay health workers from different backgrounds account for a growing segment of health coaches over the years. The planned study’s main objective is to investigate whether health coaching by lay health workers is as effective as that by health professionals. Methods The effects of health coaching intervention by lay health workers will be examined in comparison with that by health professionals within a single-blind, multi-centre, randomised controlled trial with a follow-up assessment after 3 months. A total of 380 community-dwelling older adults with chronic diseases will be recruited and randomly assigned using a 1:1 ratio into the intervention and control groups. The intervention group will receive a 3-month health coaching intervention delivered by lay health workers, whereas the control group will receive the intervention delivered by health professionals. Primary outcomes include patient activation, physical activity and nutrition behaviours. Discussion The expected findings of this study will advance the health coaching literature, research and practice by determining whether health coaching by lay health workers is as effective as that by health professionals in enhancing older adults’ knowledge, skills and confidence in chronic disease self-management and promoting changes in health behaviours. If proven effective, the inclusion of lay health workers in delivering effective self-management interventions should be advocated to reduce the over-reliance on health professionals in the primary healthcare system. Trial registration ISRCTN, ISRCTN73836238 . Registered 8 November 2023.

Background Middle-aged and older adults are more vulnerable to hospitalization and mortality if they are infected with the COVID-19 virus. The present study investigates the longitudinal effects of subjective successful aging on middle-aged and older adults’ emotional and coping responses to the COVID-19 pandemic, and explores an underlying mechanism through perceived time limitation during the pandemic. Methods A sample of 311 Hong Kong Chinese middle-aged and older adults ( M age  = 64.58, SD  = 10.14, Range = 45–90 years) were recruited from an Adult Development and Aging Project and participated in a questionnaire study via an online platform or phone interview. Their levels of subjective successful aging, perceived time limitation, and emotional and coping responses to the pandemic were measured. Results The respondents who perceived themselves as more successful in aging process reported more positive and fewer negative emotions compared with their counterparts with lower levels of subjective successful aging. The mediation analysis showed that perceived time limitation could partially account for the effects of subjective successful aging on emotional and coping responses. Conclusions Findings of this study unveil the beneficial effects of subjective views of successful aging on emotional and coping responses to the pandemic through alleviating their perception of time limitation.

Introduction: This study aimed to develop the Healthy Eating Report Card for Pre-school Children in Hong Kong for evaluating the prevalence of healthy eating behaviours and favourable family home food environments (FHFEs) among pre-school children in Hong Kong.Methods: In this cross-sectional study, 538 parent-child dyads from eight kindergartens in Hong Kong were recruited. Parents or guardians completed a questionnaire comprising Report Card items. The Report Card included two indicators of Children’s Eating Behaviours (ie, Children’s Dietary Patterns and Children’s Mealtime Behaviours) and three indicators of FHFEs (ie, Parental Food Choices and Preparation, Avoidance of Unhealthy Foods, and Family Mealtime Environments). Each indicator and its specific items were assigned a letter grade representing the percentage of participants achieving the predefined benchmarks. The grades were defined as A (≥80%, Excellent); B (60%-79%, Good); C (40%-59%, Fair); D (20%-39%, Poor); and F (<20%, Very poor). Plus (+) and minus (-) signs were used to indicate the upper or lower 5% of each grade.Results: Overall, Children’s Eating Behaviours were classified as Fair (average grade of ‘C’), whereas FHFEs were classified as Good (average grade of ‘B’). The sub-grades ranged from ‘C’ to ‘A-’, as follows: Children’s Dietary Patterns, ‘C+’; Children’s Mealtime Behaviours, ‘C’; Parental Food Choices and Preparation, ‘C+’; Avoidance of Unhealthy Foods, ‘B’; and Family Mealtime Environments, ‘A-’.Conclusion: The findings highlight areas for improvement in healthy eating among children. The Healthy Eating Report Card could offer novel insights into intervention tools that promote healthy eating.

We investigated whether circulating osteopontin (OPN) could be used as a biomarker for cervical cancer. We employed a monoclonal antibody (mAb 659) specific for the unique and intact thrombin-sensitive site in OPN using an inhibition ELISA. We found significantly higher levels of OPN in 33 cervical cancer patients in both the plasma (mean +/- SD, 612 +/- 106 ng/mL) and serum (424 +/- 121 ng/mL) compared to healthy subjects [409 +/- 56 ng/mL, from 31 plasma samples (P < 0.0001), and 314 +/- 98 ng/mL, from 32 serum samples (P = 0.0002), respectively]. Similar results were obtained when the plasma from a bigger group (147 individuals) of cervical cancer patients (560 +/- 211 ng/mL) were compared with the same plasma samples of the healthy individuals (P = 0.0014). More significantly, the OPN level was highest in stage III-IV disease (614 +/- 210 ng/mL, from 52 individuals; P = 0.0001) and least and non-discriminatory in stage I (473 +/- 110 ng/mL, from 40 individuals; P = 0.5318). No such discrimination was found when a mAb of a different specificity (mAb 446) was used in a similar inhibition ELISA to compare the two groups in the first study; a commercial capture ELISA also failed. The possibility that the target epitope recognized by the antibody probe in these assays was absent from the circulating OPN due to protein truncation was supported by gel fractionation of the OPN found in patients' plasma: 60-64 kDa fragments were found instead of the presumably full-length OPN (68 kDa) seen in healthy people. How these fragments are generated and what possible role they play in cancer biology remain interesting questions.