Neutrons produced by the carbon fusion reaction 12 C( 12 C,n) 23 Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction 12 C( 12 C,p) 23 Na. The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate, we find that 12 C( 12 C,n) 23 Mg is crucial to the production of Na and Al in Pop-III Pair Instability Supernovae. It also plays a non-negligible role in the production of weak s-process elements as well as in the production of the important galactic γ-emitter 60 Fe. The first stars in the early Universe formed about 400 million years after the big bang. Verification of the existence of these stars is important for our understanding of the evolution of the Universe [1]. It has been predicted that for Population-III (metal-free stars [2]) stellar production yields, the abundances of odd-Z elements are remarkably deficient compared to their adjacent even-Z elements [3]. Astronomers are searching for long-lived, low mass stars with the unique nucleosynthetic pattern matching the predicted yields [4]. The relevance of 12 C( 12 C,n) 23 Mg in the first stars has been discussed by Woosley, Heger, and Weaver [5]. By the end of helium burning in Pop-III stars, the neutron to proton ratio in the ash is almost exactly 1. However, in the subsequent carbon burning phase, frequent β + decay of produced 23 Mg converts protons into neutrons, thus increasing the neutron to proton ratio. A slight excess of neutrons would significantly affect the abundances of the odd-Z isotopes with neutron to proton ratios higher than 1, e.g.23 Na and 27 Al.12 C( 12 C,n) 23 Mg is also a potentially important neutron source for the so-called weak s-process occurring in massive ) and ) stars. The weak s-process takes place during the core helium and shell carbon burning phases and is largely responsible for the s-process abundances up to A≈90 [6]. Pignatari et al. recently performed a study of the weak s-process during carbon shell burning for a 25 M stellar model using different 12 C( 12 C,n) 23 Mg rates [7]. They found that a factor of 2 precision or better would be desirable to limit its impact on the s-process predictions to within 10%.Stellar carbon burning has three main reaction channels:12 C + 12 C → 23 Mg + n − 2.60 MeV → 23 Na + p + 2.24 MeVWith Q < 0, the probability of decay through the neutron channel is weakest among the three at the low energies relevant for astrophysics. For a typical carbon shell burning temperature T 9 = 1.1, the important energy range for this channel is 2.7 < E cm < 3.6 MeV. The reaction was first studied in 1969 by Patterson et al. [8] who measured t...

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Short-lived radionuclides (SLRs) with half-lives less than 100 Myr are known to have existed around the time of the formation of the solar system around 4.5 billion years ago. Understanding the production sources for SLRs is important for improving our understanding of processes taking place just after solar system formation as well as their timescales. Early solar system models rely heavily on calculations from nuclear theory due to a lack of experimental data for the nuclear reactions taking place. In 2013, Bowers et al. measured 36 Cl production cross sections via the 33 S(α,p) reaction and reported cross sections that were systematically higher than predicted by Hauser-Feshbach codes. Soon after, a paper by Peter Mohr highlighted the challenges the new data would pose to current nuclear theory if verified. The 33 S(α,p) 36 Cl reaction was re-measured at 5 energies between 0.78 MeV/A and 1.52 MeV/A, in the same range as measured by Bowers et al., and found systematically lower cross sections than originally reported, with the new results in good agreement with the Hauser-Feshbach code TALYS. Loss of Cl carrier in chemical extraction and errors in determination of reaction energy ranges are both possible explanations for artificially inflated cross sections measured in the previous work.

A novel immunomagnetic nanobeads -based lateral flow test strip was developed for the simultaneous quantitative detection of neuron specific enolase (NSE) and carcinoembryonic antigen (CEA), which are sensitive and specific in the clinical diagnosis of small cell lung cancer. Using this nanoscale method, high saturation magnetization, carboxyl-modified magnetic nanobeads were successfully synthesized. To obtain the immunomagnetic probes, a covalent bioconjugation of the magnetic nanobeads with the antibody of NSE and CEA was carried out. The detection area contained test line 1 and test line 2 which captured the immune complexes sensitively and formed sandwich complexes. In this assay, cross-reactivity results were negative and both NSE and CEA were detected simultaneously with no obvious influence on each other. The magnetic signal intensity of the nitrocellulose membrane was measured by a magnetic assay reader. For quantitative analysis, the calculated limit of detection was 0.094 ng/mL for NSE and 0.045 ng/mL for CEA. One hundred thirty clinical samples were used to validate the test strip which exhibited high sensitivity and specificity. This dual lateral flow test strip not only provided an easy, rapid, simultaneous quantitative detection strategy for NSE and CEA, but may also be valuable in automated and portable diagnostic applications.