Neutron capture reactions are the main contributors to the synthesis of heavy elements through the s-process. 22Ne(α,n)25Mg is the main neutron source in stars, together with 13C(α,n)16O. At energies Ecm < 700 keV, limited data are available, i.e., reaction cross-section upper limits from direct experiments and highly uncertain estimates from indirect sources exist. The ERC project SHADES is currently performing direct cross-section measurements at these energies. We will present details on the ongoing experiment and discuss target characteristics, experimental backgrounds, and preliminary analyses on the detector efficiency and the 832 keV resonance.

Type Ia supernovae (SNIa) are thermonuclear explosions of white dwarfs in binary systems. They are central to galactic chemical evolution and serve as standardizable candles in cosmology, yet their progenitors remain uncertain. In this work, we present a grid of five models detailing the evolution and nucleosynthesis of slowly merging carbon-oxygen white dwarfs approaching the Chandrasekhar mass. These models test a variety of physics input settings, including accretion rates, nuclear reaction rates, convection parameters, and the composition of the accreted material. During the merger process, as the mass of the primary white dwarf approaches the Chandrasekhar limit, carbon burning is initiated first on the surface before eventually igniting explosively at the center. As a consequence, the 22Ne(a,n)25Mg reaction activates in the outer layers of all models. The neutrons released in this way produce a weak s-process-like abundance distribution peaking at Kr, which is overproduced by more than a factor of 1000 compared to solar. The trans-Fe elements-enriched outer layer mass varies from 0.04 Msun to 0.11 Msun, depending on the accretion rate. Our explosion simulation of these progenitor models ejects significant amount of first-peak elements (e.g., Kr, Sr) as well as of some long-lived radioactive species, such as 60Fe. In a previous theoretical study, we found that a similar nucleosynthesis process during the progenitor phase may also occur on the surface of near-Chandrasekhar white dwarfs formed through the accretion of H-rich material via the single-degenerate scenario. Therefore, these results suggest trans-Fe enrichment might be a hallmark of near-Chandrasekhar SNIa ejecta, regardless of the specific progenitor channel, and could provide a new spectral signature distinguishing them from sub-Chandrasekhar explosions.

Neutron capture reactions are the main contributors to the synthesis of the heavy elements through the s-process. Together with ^13C(α,n)16O, which has recently been measured by the LUNA collaboration in an energy region inside the Gamow peak, 22Ne(α,n)25Mg is the other main neutron source in stars. Its cross section is mostly unknown in the relevant stellar energy (450 keV < Ecm < 750 keV), where only upper limits from direct experiments and highly uncertain estimates from indirect sources exist. The ERC project SHADES (UniNa/INFN) aims to provide for the first time direct cross section data in this region and to reduce the uncertainties of higher energy resonance parameters. High sensitivity measurements will be performed with the new LUNA-MV accelerator at the INFN-LNGS laboratory in Italy: the energy sensitivity of the SHADES hybrid neutron detector, together with the low background environment of the LNGS and the high beam current of the new accelerator promises to improve the sensitivity by over 2 orders of magnitude over the state of the art, allowing to finally probe the unexplored low-energy cross section. Here we present an overview of the project and first results on the setup characterization.

The 22Ne(α,n)25Mg reaction is of major importance in nuclear astrophysics. It is the main neutron source for the weak s-process and as such is responsible for the nucleosynthesis of 60 < A < 90 elements. In addition, it provides a strong neutron burst during the later, hottest phases of the main s-process, which modifies the final nucleosynthesis products, especially at so-called branch points, which can be used to provide insight into the stellar interior at that time. The reaction rate needs to be known below ca. 900 keV, and due to the low cross-section at these energies, a direct measurement has so far proven to be severely hampered by external neutron background at the surface of the Earth. To solve this problem, a measurement campaign (the ERC-funded SHADES project) was recently started at the deep underground Gran Sasso National Laboratory (LNGS) in Italy. We provide an overview of the experiment status and an outlook into the near future.

22Ne(α, γ)26Mg is pivotal in the understanding of several open astrophysical questions, as the nucleosynthesis beyond Fe through the s-process, but its stellar reaction rate is still subject to large uncertainties. These mainly arise from its extremely low rate in the Gamow energy region, whose measurement is hampered by the unavoidable presence of the cosmic ray background noise. A possibility to overcome this issue is to perform the measurement in a quasi background-free environment, such as that offered by the underground Bellotti Ion Beam Facility at LNGS. This is the key idea of EASγ experiment. In this study, the signal from the de-excitation of the compound nucleus 26Mg has been simulated and its detection has been investigated both on surface and deep-underground laboratories. The simulation results show the enhancement in sensitivity achieved by performing the measurement deep underground and with an additional shielding, yielding to unprecedented sensitivity.

For more than three decades, accelerators are in use in the underground laboratories of the Laboratori Nazionali del Gran Sasso (LNGS), located in central Italy. The LUNA Collaboration has exploited the potential of the site’s low cosmic ray background to achieve important and often groundbreaking results in the field of nuclear astrophysics. This long success story stimulated the installation of accelerators in deep underground laboratories also in other countries, including the USA and China. Recently, LNGS took a major step forward with the activation of the Bellotti Ion Beam Facility, which will provide ion beams to the scientific community for research not only in nuclear astrophysics, but in all fields that can benefit from the low cosmic ray background conditions of the underground site.

12C fusion reactions are among the most important in stellar evolution since they determine the destiny of massive stars. Over the past fifty years, massive efforts have been done to measure these reactions at low energies. However, existing data present several discrepancies between sets and large uncertainties specially at the lowest energies. Factors such as beam/environmental backgrounds, extremely low cross sections and insufficient knowledge of the reaction mechanism contribute to these problems. Recently, the ERNA collaboration measured the 12C+12C reactions at Ec.m. = 2.51 - 4.36 MeV with energy steps between 10 and 25 keV in the centre of mass. Representing the smallest energy steps to date. In these measurements, beam induced background was minimised and S-factors for the proton and alpha channels were calculated. Results indicate that a possible explanation for the discrepancies between data sets is the wrongly assumed constant branching ratios and isotropical angular distributions. Given the excellent performance of the detectors for low energy measurements, a collaboration with the LUNA group (LNGS) has started. Background measurements underground are being performed and results indicate it could be possible to measure the 12C+12C reactions directly into the Gamow Window.

In deep-underground experiments, intrinsic detector background can exceed the external one, limiting the detection sensitivity. Intrinsic background in liquid scintillator neutron detectors consists of a particles emitted from radioactive impurities in the detector housing (and possibly in the liquid). We present the results of long background measurements of 12 EJ -309 liquid organic scintillators detectors in the deep-underground Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics. These detectors are a part of the detection array for the SHADES ERC project that aims to measure the very low cross section (down to picobarn) of the astrophysically important reaction 22Ne(a, n)25Mg. With an exposure of similar to 35 days we identify an actinide concentration in the detector housing of 8.4(1.8)sta(1.4)sys x 10-2 ppm and 1.62(0.57)sta(0.03)sys x 10-1 ppm of 238U and 232Th, resulting in 64 a particle counts per hour. The half-life of 214Po was also determined as 163.7(11)mu s.

Tuberculosis is the deadliest bacterial disease globally, threatening the lives of millions every year. New antibiotic therapies that can shorten the duration of treatment, improve cure rates, and impede the development of drug resistance are desperately needed. Here, we used polymeric micelles to encapsulate four second-generation derivatives of the antitubercular drug pretomanid that had previously displayed much better in vivo activity against Mycobacterium tuberculosis than pretomanid itself. Because these compounds were relatively hydrophobic and had limited bioavailability, we expected that their micellar formulations would overcome these limitations, reduce toxicities, and improve therapeutic outcomes. The polymeric micelles were based on polypept(o)ides (PeptoMicelles) and were stabilized in their hydrophobic core by π-π interactions, allowing the efficient encapsulation of aromatic pretomanid derivatives. The stability of these π-π-stabilized PeptoMicelles was demonstrated in water, blood plasma, and lung surfactant by fluorescence cross-correlation spectroscopy and was further supported by prolonged circulation times of several days in the vasculature of zebrafish larvae. The most efficacious PeptoMicelle formulation tested in the zebrafish larvae infection model almost completely eradicated the bacteria at non-toxic doses. This lead formulation was further assessed against Mycobacterium tuberculosis in the susceptible C3HeB/FeJ mouse model, which develops human-like necrotic granulomas. Following intravenous administration, the drug-loaded PeptoMicelles significantly reduced bacterial burden and inflammatory responses in the lungs and spleens of infected mice.

The detection of neutrons in low energy astrophysics poses two main problems: low cross section measurement requires high detection efficiency and ideally, beam-induced and external neutron backgrounds should be identified through an energy sensitive detector. In recent years, capture-gated neutron spectroscopy has found new opportunities to grow through new materials and better availability of modern data acquisition systems. In this work we will present the design, expected capabilities and preliminary characterization of the hybrid neutron detector array SHADES. Its purpose is the first direct measurement of the reaction 22Ne(α, n)25Mg in the Gamow window for s-process nucleosynthesis with LUNA-MV in the deep underground environment of the LNGS.

12C+12C reactions are crucial in the evolution of massive stars and explosive scenarios. The measurement of these reactions at astrophysical energies is very challenging due to their extremely small cross sections, and the presence of beam induced background originated by the natural 1,2H contaminants in the C targets. In addition, the many discrepancies between different data sets and the complicated resonant structure of the cross sections make the extrapolation to low energies very uncertain. Recently, we performed a direct measurement of the 12C+12C reactions at the CIRCE Laboratory in Italy. Results from a study on target contamination were used, allowing us to measure cross sections at Ec.m. =2.51 − 4.36 MeV with 10-25 keV energy steps. Two stage ΔE-Erest detectors were used for unambiguous particle identification. Branching ratios of individual particle groups were found to vary significantly with energy and angular distributions were also found to be anisotropic, which could be a potential explanation for the discrepancies observed among different data sets.

We present an experimental approach to studying the kinetics of polymer nanoparticle formation using molecular rotor molecules as fluorescence probes. By combining fluorescence lifetime analysis and fluorescence correlation spectroscopy, it is possible to simultaneously monitor the evolution of the local environment in the nanoparticles and their size. To assess the generality of the method, we select two common but very different methods for nanoparticle preparation: emulsion-solvent evaporation and miniemulsion polymerization. In both cases, three stages of the nanoparticle formation process were identified on the basis of their polymer content. In the initial stage of the process, the polymer content is low. Then it increases rapidly because of solvent evaporation or polymerization during the second stage. Finally, it reaches a plateau value. Furthermore, significant heterogeneities in the final nanoparticles were found that can be attributed to remaining solvent or monomer and the spatial variation of the polymer-free volume.

The generation of specific humoral and cellular immune responses plays a pivotal role in the development of effective vaccines against tumors. Especially the presence of antigen-specific, cytotoxic T cells influences the outcome of therapeutic cancer vaccinations. Different strategies, ranging from delivering antigen-encoding mRNAs to peptides or full antigens, are accessible but often suffer from insufficient immunogenicity and require immune-boosting adjuvants as well as carrier platforms to ensure stability and adequate retention. Here, we introduce a pH-responsive nanogel platform as a two-component antitumor vaccine that is safe for intravenous application and elicits robust immune responses in vitro and in vivo. The underlying chemical design allows for straightforward covalent attachment of a model antigen (ovalbumin) and an immune adjuvant (imidazoquinoline-type TLR7/8 agonist) onto the same nanocarrier system. In addition to eliciting antigen-specific T and B cell responses that outperform mixtures of individual components, our two-component nanovaccine leads in prophylactic and therapeutic studies to an antigen-specific growth reduction of different tumors expressing ovalbumin intracellularly or on their surface. Regarding the versatile opportunities for functionalization, our nanogels are promising for the development of highly customized and potent nanovaccines.

This investigation reports on the thermomechanical properties of Poly-tripropyleneglycoldiacrylate (Poly-TPGDA)/liquid crystal (LC) blends, developed via free radical polymerization processes, which are induced by Electron Beam (EB) and Ultraviolet (UV) radiation. The EB-cured Poly-TPGDA network exhibits a higher glass transition temperature (Tg), a higher tensile storage, and Young moduli than the corresponding UV-cured sample, indicating a lower elasticity and a shorter distance between the two adjacent crosslinking points. Above Tg of Poly-TPGDA/LC blends, the LC behaves as a plasticizing agent, whereas, for EB-cured networks, at temperatures below Tg, the LC shows a strong temperature dependence on the storage tensile modulus: the LC reinforces the polymer due to the presence of nano-sized phase separated glassy LC domains, confirmed by electron microscopy observations. In the case of the UV-cured TPGDA/LC system, the plasticizing effect of the LC remains dominant in both the whole composition and the temperature ranges explored. The rubber elasticity and Tg of Poly-TPGDA/LC films were investigated using mechanical measurements.

It is well established that the 13 C ( α , n ) 16 O reaction (Q=2.215 MeV) is the major neutron source feeding the s -process in low mass (1−3 M ⊙ ) Asymptotic Giant Branch (AGB) stars. In the last decades, several measurements have been performed. Nevertheless, no dataset reaches the Gamow window (140 keV = 200 µ A). Thanks to these accuracies, the 13 C ( α , n ) 16 O cross section was measured in the center of mass energy range 230 keV

Background: The competing Ne-23(alpha, gamma)Mg-26 and Ne-22(alpha, n)Mg-25 reactions control the production of neutrons for the weak s process in massive and asymptotic giant branch (AGB) stars. In both systems, the ratio between the corresponding reaction rates strongly impacts the total neutron budget and strongly influences the final nucleosynthesis. A number of experimental studies have been performed over recent years which necessitate g the reevaluation of the Ne-23(alpha, gamma)Mg-26 and Ne-22(alpha, n)Mg-25 reaction rates. Evaluations of the reaction rates following the collection of new nuclear data presently show differences of up to a factor of 500, resulting in considerable uncertainty in the resulting nucleosynthesis. Purpose: To reevaluate the Ne-23(alpha, gamma)Mg-26 and Ne-22(alpha, n)Mg-25 reaction rates using updated nuclear data from a number of sources including updating spin and parity assignments. Methods: With updated spin and parity assignments, the levels which can contribute to the reaction rates are identified. The reaction rates are computed using a Monte Carlo method which has been used for previous evaluations of the reaction rates in order to focus solely on the changes due to modified nuclear data. Results: The evaluated Ne-22(alpha, gamma)Mg-26 reaction rate remains substantially similar to that of Longland et al. but, including recent results from Texas A&M, the Ne-22(alpha, n)Mg-25 reaction rate is lower at a range of astrophysically important temperatures. Stellar models computed with NEWTON and MESA predict decreased production of the weak branch s process due to the decreased efficiency of Ne-22 as a neutron source. Using the new reaction rates in the MESA model results in Zr-96 / Zr-94 and Ba-135 / Ba-136 ratios in much better agreement with the measured ratios from presolar SiC grains. Conclusion: The Ne-22 + alpha reaction rates Ne-22(alpha, gamma)Mg-26 and Ne-22(alpha.n) Mg-25 have been recalculated based on more recent nuclear data. The Ne-22(alpha, gamma)Mg-26 reaction rate remains substantially unchanged since the previous evaluation but the Ne-22(alpha.n)Mg-25 reaction rate is substantially decreased due to updated nuclear data. This results in significant changes to the nucleosynthesis in the weak branch of the s process.

Anticounterfeiting materials are used to distinguish real banknotes, products, and documents from counterfeits, fakes, or unauthorized replicas. However, conventional anticounterfeiting materials generally exhibit a single anticounterfeiting function, resulting in a low level of security. Herein, a novel anticounterfeiting nanocomposite is demonstrated with numerous prominent security features. The nanocomposite is fabricated by doping upconverting nanoparticles (UCNPs) in a photoresponsive azobenzene‐containing polymer (azopolymer). Because of the cis – trans photoisomerization of the azopolymer, the nanocomposite exhibits photoinduced reversible color changes suitable for anticounterfeiting applications. Additionally, the hard nanocomposite can be converted to a rubber‐like soft solid by light irradiation. Imprinted microstructures are fabricated on the photosoftened nanocomposite, which result in photonic colors. Moreover, polarization‐dependent structures are fabricated on the nanocomposite via photoinduced orientation for encryption. Importantly, UCNPs in the nanocomposite emit visible light upon excitation by near‐infrared light, enabling the observation of various anticounterfeiting structures with high contrast. An advantage of the anticounterfeiting nanocomposite is that the security features can be observed by the naked eye for quick discrimination and can be analyzed using laboratory equipment for higher accuracy. The anticounterfeiting nanocomposite is easily processed on paper, glass, and plastic, which demonstrates its potential anticounterfeiting functions for banknotes, wines, and medicines.

The anisotropic charge carrier diffusion coupled to ferroelastic twin domains in methylammonium lead iodide opens possibilities for further optimization of perovskite solar cells and optoelectronic devices via strain engineering and heat treatments.

In applications superhydrophobic surfaces are often irregular and nanostructured. On such a surface, it has been found that only a part of the surface is homogeneously wetted, i.e. wetting and slippage corresponding to that of a regularly structured surface. On the remaining part, large air inclusions occurred that possess a comparatively large slip length. In order to measure the velocity profile at distances below 1\textmu{}m close to the surface, an enhanced evaluation method for fluorescence correlation spectroscopy is developed in this work.

The competing ^22Ne(α,γ)^26Mg and ^22Ne(α,n)^25Mg reactions control the production of neutrons for the weak s-process in massive and AGB stars. In both systems, the ratio between the corresponding reaction rates strongly impacts the total neutron budget and strongly influences the final nucleosynthesis. The ^22Ne(α,γ)^26Mg and ^22Ne(α,n)^25Mg reaction rates was re-evaluated by using newly available information on ^26Mg given by various recent experimental studies. Evaluations of The evaluated ^22Ne(α,γ)^26Mg reaction rate remains substantially similar to that of Longland et al. but, including recent results from Texas A&M, the ^22Ne(α,n)^25Mg reaction rate is lower at a range of astrophysically important temperatures. Stellar models computed with NEWTON and MESA predict decreased production of the weak branch s-process due to the decreased efficiency of ^22Ne as a neutron source. Using the new reaction rates in the MESA model results in ^96Zr/^94Zr and ^135Ba/^136Ba ratios in much better agreement with the measured ratios from presolar SiC grains.