Chirped pulse Raman amplification in warm plasma: towards controlling saturation

Stimulated Raman backscattering in plasma is potentially an efficient method of amplifying laser pulses to reach exawatt powers because plasma is fully broken down and withstands extremely high electric fields. Plasma also has unique nonlinear optical properties that allow simultaneous compression of optical pulses to ultra-short durations. However, current measured efficiencies are limited to several percent. Here we investigate Raman amplification of short duration seed pulses with different chirp rates using a chirped pump pulse in a preformed plasma waveguide. We identify electron trapping and wavebreaking as the main saturation mechanisms, which lead to spectral broadening and gain saturation when the seed reaches several millijoules for durations of 10's - 100's fs for 250 ps, 800 nm chirped pump pulses. We show that this prevents access to the nonlinear regime and limits the efficiency, and interpret the experimental results using slowly-varying-amplitude, current-averaged particle-in-cell simulations. We also propose methods for achieving higher efficiencies.close0

The Chest Pain Choice trial: a pilot randomized trial of a decision aid for patients with chest pain in the emergency department

Background: Chest pain is a common presenting complaint in the emergency department (ED). Despite the frequency with which clinicians evaluate patients with chest pain, accurately determining the risk of acute coronary syndrome (ACS) and sharing risk information with patients is challenging. The aims of this study are (1) to develop a decision aid (CHEST PAIN CHOICE) that communicates the short-term risk of ACS and (2) to evaluate the impact of the decision aid on patient participation in decision-making and resource use. Methods/Design: This is a protocol for a parallel, 2-arm randomized trial to compare an intervention group receiving CHEST PAIN CHOICE to a control group receiving usual ED care. Adults presenting to the Saint Mary's Hospital ED in Rochester, MN USA with a primary complaint of chest pain who are being considered for admission for prolonged ED observation in a specialized unit and urgent cardiac stress testing will be eligible for enrollment. We will measure the effect of CHEST PAIN CHOICE on six outcomes: (1) patient knowledge regarding their short-term risk for ACS and the risks of radiation exposure; (2) quality of the decision making process; (3) patient and clinician acceptability and satisfaction with the decision aid; (4) the proportion of patients who decided to undergo observation unit admission and urgent cardiac stress testing; (5) economic costs and healthcare utilization; and (6) the rate of delayed or missed ACS. To capture these outcomes, we will administer patient and clinician surveys after each visit, obtain video recordings of the clinical encounters, and conduct 30-day phone follow-up. Discussion: This pilot randomized trial will develop and evaluate a decision aid for use in ED chest pain patients at low risk for ACS and provide a preliminary estimate of its effect on patient participation in decision-making and resource use

Inhibition of Proliferation and Induction of Apoptosis in Multiple Myeloma Cell Lines by CD137 Ligand Signaling

BACKGROUND: Multiple myeloma (MM) is a malignancy of terminally-differentiated plasma cells, and the second most prevalent blood cancer. At present there is no cure for MM, and the average prognosis is only three to five years. Current treatments such as chemotherapy are able to prolong a patient's life but rarely prevent relapse of the disease. Even hematopoietic stem cell transplants and novel drug combinations are often not curative, underscoring the need for a continued search for novel therapeutics. CD137 and its ligand are members of the Tumor Necrosis Factor (TNF) receptor and TNF superfamilies, respectively. Since CD137 ligand cross-linking enhances proliferation and survival of healthy B cells we hypothesized that it would also act as a growth stimulus for B cell cancers. METHODOLOGY/PRINCIPAL FINDINGS: Proliferation and survival of B cell lymphoma cell lines were not affected or slightly enhanced by CD137 ligand agonists in vitro. But surprisingly, they had the opposite effects on MM cells, where CD137 ligand signals inhibited proliferation and induced cell death by apoptosis. Furthermore, secretion of the pro-inflammatory cytokines, IL-6 and IL-8 were also enhanced in MM but not in non-MM cell lines in response to CD137 ligand agonists. The secretion of these cytokines in response to CD137 ligand signaling was consistent with the observed activation of the classical NF-kappaB pathway. We hypothesize that the induction of this pathway results in activation-induced cell death, and that this is the underlying mechanism of CD137-induced MM cell death and growth arrest. CONCLUSIONS/SIGNIFICANCE: These data point to a hitherto unrecognized role of CD137 and CD137 ligand in MM cell biology. The selective inhibition of proliferation and induction of cell death in MM cells by CD137 ligand agonists may also warrant a closer evaluation of their therapeutic potential

Development and validation of the Multi-dimensional University Research Workplace Inventory (MDURWI)

WOS:000454839600005This study describes the development and validation of an instrument aimed toward measuring organizational features of an academic research workplace. The question pool was developed based on data from a pilot study (N = 43). The survey was deployed to academic researchers in the field of higher education research worldwide (N = 850). An exploratory factor analysis conducted on 36 questions, followed by confirmatory factor analysis, which lead to a final pool of 27 questions in five subscales, one of which divided into three lower-order factors. The final model exhibited very good fit (X2/df = 2.561; CFI = 0.972; PCFI = 0.784; RMSEA = 0.043; P[rmsea ? 0.05] < 0.001; AIC = 891.018; BCC = 987.839) and psychometric properties, in the form of factorial, convergent, and discriminant validity, as well as reliability and sensitivity. Implications of this instrument for research and policymaking are discussed, as well as future research directions.info:eu-repo/semantics/acceptedVersio

Major Cellular and Physiological Impacts of Ocean Acidification on a Reef Building Coral

As atmospheric levels of CO2 increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO2 conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification

Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure