Nuclear Contribution Research Articles

Creation of true interspecies hybrids: Rescue of hybrid class with hybrid cytoplasm affecting growth and metabolism.

Interspecies hybrids have nuclear contributions from two species but oocyte cytoplasm from only one. Species discordance may lead to altered nuclear reprogramming of the foreign paternal genome. We reasoned that initial reprogramming in same species cytoplasm plus creation of hybrids with zygote cytoplasm from both species, which we describe here, might enhance nuclear reprogramming and promote hybrid development. We report in Mus species that (i) mammalian nuclear/cytoplasmic hybrids can be created, (ii) they allow development and viability of a previously missing and uncharacterized hybrid class, (iii) different oocyte cytoplasm environments lead to different phenotypes of same nuclear hybrid genotype, and (iv) the novel hybrids exhibit sex ratio distortion with the absence of female progeny and represent a mammalian exception to Haldane's rule. Our results emphasize that interspecies hybrid phenotypes are not only the result of nuclear gene epistatic interactions but also cytonuclear interactions and that the latter have major impacts on fetal and placental growth and development.

Assessment of Nuclear Fusion Reaction Spontaneity via Engineering Thermodynamics.

This work recalls the basic thermodynamics of chemical processes for introducing the evaluation of the nuclear reactions' spontaneity. The application and definition of the thermodynamic state functions of the nuclear processes have been described by focusing on their contribution to the chemical potential. The variation of the nuclear binding potentials involved in a nuclear reaction affects the chemical potential through a modification of the internal energy and of the other state functions. These energy changes are related to the mass defect between reactants and products of the nuclear reaction and are of the order of magnitude of 1 MeV per particle, about six orders of magnitude larger than those of the chemical reactions. In particular, this work assesses the Gibbs free energy change of the fusion reactions by assuming the Qvalue as the nuclear contribution to the chemical potential and by calculating the entropy through the Sackur-Tetrode expression. Then, the role of the entropy in fusion processes was re-examined by demonstrating the previous spontaneity analyses, which assume a perfect gas of DT atoms in the initial state of the fusion reactions, are conservative and lead to assessing more negative ΔG than in the real case (ionized gas). As a final point, this paper examines the thermodynamic spontaneity of exothermic processes with a negative change of entropy and discusses the different thermodynamic spontaneity exhibited by the DT fusion processes when conducted in a controlled or uncontrolled way.

Carbon-14 cycling in a nuclearized river: A first study in the downstream part of the Rhône River (France)

Carbon-14 (14C) has a natural origin but is also anthropogenically released from civil nuclear facilities. Due to its long decay period (half-life: 5700 ± 30 years), it is a persistent radionuclide in the environment. In rivers, the complex speciation of carbon makes the fate of industrial 14C difficult to track. This study reports a first overview of artificial 14C cycling in a nuclearized river. A one-year sampling campaign was conducted on the French nuclearized Rhône River and two of its non-nuclearized tributaries (Durance and Ardèche rivers). Isotopic (δ13C, Δ14C) and carbon concentrations analyses were performed on the particulate organic carbon (POC), dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC). Chlorophyll-a (Chl-a) and tritium analyses were performed to assess the dynamic of aquatic organic matter and the nuclear industry contribution, respectively. Comparisons of Δ14C data obtained from the Rhône River with those from the tributaries highlight significant industrial radiocarbon labelling in all carbon forms, with medians of 142, 130 and 42 ‰ for POC, DOC and DIC, that are 2–3 times higher than those of the tributaries. The high values of Chl-a/POC ratios with Δ14C-enriched POC suggest a biological uptake of artificial Δ14C in DIC by aquatic photosynthesis. The relationship of Δ14C-DIC with tritium activity indicates a response to recent releases and enables the contribution of nuclear power plants to be estimated at a median of 26 %. Sampling at the Rhône's mouth would reinforce our understanding of the fate of riverine 14C when entering the marine environment.

The genomic mosaic of mitochondrial dysfunction: Decoding nuclear and mitochondrial epigenetic contributions to maternally inherited diabetes and deafness pathogenesis

AimsMaternally inherited diabetes and deafness (MIDD) is a complex disorder characterized by multiorgan clinical manifestations, including diabetes, hearing loss, and ophthalmic complications. This pilot study aimed to elucidate the intricate interplay between nuclear and mitochondrial genetics, epigenetic modifications, and their potential implications in the pathogenesis of MIDD. Main methodsA comprehensive genomic approach was employed to analyze a Sicilian family affected by clinically characterized MIDD, negative to the only known causative m.3243 A > G variant, integrating whole-exome sequencing and whole-genome bisulfite sequencing of both nuclear and mitochondrial analyses. Key findingsRare and deleterious variants were identified across multiple nuclear genes involved in retinal homeostasis, mitochondrial function, and epigenetic regulation, while complementary mitochondrial DNA analysis revealed a rich tapestry of genetic diversity across genes encoding components of the electron transport chain and ATP synthesis machinery. Epigenetic analyses uncovered significant differentially methylated regions across the genome and within the mitochondrial genome, suggesting a nuanced landscape of epigenetic modulation. SignificanceThe integration of genetic and epigenetic data highlighted the potential crosstalk between nuclear and mitochondrial regulation, with specific mtDNA variants influencing methylation patterns and potentially impacting the expression and regulation of mitochondrial genes. This pilot study provides valuable insights into the complex molecular mechanisms underlying MIDD, emphasizing the interplay between nucleus and mitochondrion, tracing the way for future research into targeted therapeutic interventions and personalized approaches for disease management.

Proton and neutron density distributions at supranormal density in low- and medium-energy heavy-ion collisions. II. Central Pb + Pb collisions

This paper represents a continuation of our investigation into the limitations on total, proton, and neutron particle number densities, as well as the asymmetry of proton and neutron density distributions achievable in central heavy-ion collisions. We explore these aspects at low and medium energies within the framework of the Boltzmann-Uhlenbeck-Uehling (pBUU) transport and time-dependent Hartree-Fock (TDHF) models. Previous studies, focusing on symmetric and asymmetric collisions of Ca and Sn nuclei [1], and initial results on Pb-nuclei collisions [2], emphasized the role of the Coulomb interaction in these events. Our findings indicated that: (i) the highest total densities predicted at Ebeam=800 MeV/nucleon were on the order of ≈2.5ρ0 (ρ0=0.16fm−3), (ii) the proton-neutron asymmetry for maximal densities, δ=(ρnmax−ρpmax)/(ρnmax+ρpmax), did not generally exceed the asymmetry in the initial state of the collision at all beam energies and tended to decrease during the reaction, and (iii) a significant portion of this asymmetry had its microscopic origin in Coulomb forces, masking the pure nuclear contribution. These new findings, particularly relevant in the astrophysical context, are further examined in this work, focusing on the heaviest target-projectile combination Pb212,208 accessible in an experiment. We introduce the SkT3 Skyrme force model, not previously used for the Pb system, and compare it to the SV-bas and SV-sym34 models to explore the symmetry-energy dependence of the results. Contour plots of nucleonic densities are presented, contrasting the time evolution of the density distributions in low (TDHF) and high (pBUU) models. We also present the evolution of normalized maximal proton, neutron, and total nucleon number density with increasing beam energy in the full pBUU model and the Vlasov approximation, aiming to explore the impact of correlations in the reaction. The time evolution of the proton and neutron density distributions in the plane transverse to the beam direction is illustrated at both low and high beam energy. In conclusion, our detailed examination of the Pb system in this work provides further essential evidence that the aforementioned findings (i)–(iii) are only weakly dependent on system size and a symmetry-energy model, and thus, they are of more general importance. Published by the American Physical Society 2024

Advancing stroke diagnosis and management through nuclear medicine: a systematic review of clinical trials.

Despite advancements in stroke care, challenges persist in timely triage and treatment initiation to prevent the burden of stroke-related disabilities. Although nuclear medicine has shown promise, no imaging technique has yet provided a sufficiently rapid, precise, and cost-effective approach to routine stroke management. This study aims to review the clinical application of nuclear medicine in stroke diagnosis and treatment. A systematic search of the Cochrane, EU Clinical Trials Register, ISRCTN, the International Stroke Trial, and the ClinicalTrials.gov database was conducted to find all registered trials reporting nuclear medicine's clinical applications in stroke up to June 07, 2024. Among the 220 screened trials, 51 (36 interventional; 15 observational) met the eligibility criteria. Participants were older than 18 years old, with only six studies including pediatric under 17 years old, with a total of 11,262 stroke (9,232 ischemic; 2,030 haemorrhagic) participants. The bias risk varied across trials but remained mostly low to moderate. The review highlighted nuclear medicine's significant contributions to stroke diagnosis and management, notably through mobile stroke units, pre-hospital acute stroke magnetic resonance image (MRI) based biomarkers, and MRI-based stroke mechanisms for 4D flow nuclear imaging. These advancements have generally reduced treatment delays and enhance clinical outcomes post-stroke. Specifically, radiopharmaceutical radiotracers can effectively discriminate between strokes and mimics, particularly in high-risk patients. Integrating novel positron emission tomography (PET) radiotracer 18F glycoprotein 1 and radionuclide angiography may improve sensitivity and specificity in thrombi detection for decisions regarding stenting or carotid endarterectomy, and the single-photon emission computed tomography and PET integration with ferumoxytol radiotracer-enhanced MRI enables functional imaging for evaluating cerebral perfusion, metabolic activity, and neuroinflammatory markers post-stroke. Overall, the integration of nuclear medicine into multimodal imaging equipment like computed-tomography PET and MRI-PET offers a more comprehensive picture of the brain. Nevertheless, further research is needed on novel stroke imaging techniques and standardization across stroke centers for optimal performance. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024541680, identifier PROSPERO CRD(42024541680).

Coulomb and symmetry-energy effects on proton and neutron density-distributions in central heavy-ion collisions, across beam energies and system masses

In this contribution, we review our current and previous investigations of total, proton, and neutron particle number densities and the asymmetry of proton and neutron density distributions achievable in central heavy-ion collisions at beam energy below 800 MeV/nucleon. Furthermore, the effects of the Coulomb interaction and the dependence on a system size in three representative symmetric and asymmetric Ca, Sn and Pb systems are studied. The Boltzmann-Uhlenbeck-Uehling (pBUU) transport and Time-Dependent Hartree-Fock (TDHF) models, employing the SVbas, SkT3 and SVsym Skyrme interactions, are used in these simulations. We find that (i) the highest total densities predicted at Ebeam = 800 MeV/nucleon are on the order of ∼ 2.5ρ0 (ρ0 = 0.16 fm−3), (ii) the proton-neutron asymmetry for maximal densities, δ = (ρnmax−ρpmax)/(ρnmax+ρpmax) do not generally exceed the asymmetry in the initial state of the collision at all beam energies and tend to decrease during the reaction, and (iii) a significant portion of this asymmetry has its microscopic origin in Coulomb forces, masking the pure nuclear contribution. In addition, the evolution of normalized maximal proton, neutron, and total nucleon number density with increasing beam energy, the impact of correlations in the reaction, and the time evolution of the proton and neutron density distributions in the plane transverse to the beam direction are illustrated and discussed.

Convergence of alkaline earth and transition metal oxide nanotube properties toward the 2D slab limit, computational investigation for energy conversion implications

Nanoscale devices developed from low-dimensional materials (one and two-dimensional systems) have recently attracted great attention due to their critical applications in micro/nano electromechanics. However, the practical fabrication of 2D systems is often more challenging than that of their 1D counterparts. In the current investigation, the convergence of 1D nanotube properties toward the 2D slab limit has been verified and confirmed. In this regard, a variety of geometrical, electronic, and response (mechanical and piezoelectric) properties are computed for both zigzag (n,0) metal oxide MO (M = Be, Mg, Ca, Zn, Cd) nanotubes and MO 2D surfaces. The variation of such properties as a function of the tube index n (ranging from 6 to 48, corresponding to 24 to 192 atoms per cell, respectively) is highlighted. Additionally, the electronic and nuclear contributions to all aforementioned response properties have been discussed and analyzed. Interestingly, CdO (48,0) nanotube introduces considerable direct and converse piezoelectric constants: e11 = 6.04 |e|×bohr and d11 = 22.88 pm/V. These electromechanical coefficients converge well to the values of the 2D surface, while the response is entirely dominated by the ionic contribution, confirming the flexibility and softness. Such findings make these MO nanotubes good candidates for nanoscale energy conversion piezoelectric applications.

Abstract 14665: Cybrid Analysis Delineates Nuclear and Mitochondrial Contributions to Oxidative Stress in Pulmonary Arterial Hypertension

Rationale : Heritable pulmonary arterial hypertension (HPAH) is a serious vasculopathy caused by remodeling of pulmonary arterioles. It is inherited in an autosomal dominant pattern with reduced penetrance, suggesting additional triggers are needed for disease development. Past study shows increased DNA damage and total reactive oxygen species (ROS) in lymphoblastoid cells (LCL) from PAH patients and unaffected relatives, indicating a potential genetic component. Hypothesis: Increased oxidative stress is an independent genetically-determined modifier of PAH susceptibility. Methods: LCL from patients, relatives and unrelated controls were analyzed for total and mitochondrial (mt) ROS and mt function (Seahorse). Untargeted metabolomics were performed by Metabolon. Nuclear vs mt gene contribution was studied using cybrids created by transferring the mitochondria from high (HC) and low ROS LCL (LC) to mt negative 143B Rho0 cells. Results: Metabolomics revealed significant differences between PAH and control LCL in the TCA cycle and glutathione metabolism relating to oxidative stress. HPAH LCL showed significant upregulation of both ROS species compared to controls. LCL from relatives clustered into two groups, one with increased mtROS, the other comparable to controls . Like PAH lung vascular cells, LCL with increased mtROS had reduced spare respiratory capacity (SRC) suggesting dysfunctional mitochondria, but no glycolytic switch. Cybrid analysis revealed that HCs had significantly higher basal respiration (p=0.02), with SRC trending higher compared to LCs, indicating a functional electron transport chain. These cells also had elevated mtROS (p=0.04), suggesting reduced antioxidants. Conclusions: HPAH is a complex disease, and mutation status alone doesn’t determine its susceptibility. Patient LCL recapitulate some of the metabolomic pathways dysregulated in lung vascular cells. Oxidative stress in LCL extends to some unaffected relatives, suggesting this is an independent genetic trait that modifies PAH risk. Our cybrid analysis, novel in PAH highlights the importance of nuclear-mt crosstalk. WGS is underway to identify nuclear variants that could affect the mt, and act as potential modifiers and second hits in PAH pathogenesis.

DFT studies on structural stability, vibrational and linear and nonlinear optical properties of low-dimensional zinc sulfide: from the 3D bulk to the 2D monolayer and the 1D zigzag single-walled nanotubes

Through first-principles calculations, we investigate structural stability, vibrational and linear and nonlinear optical properties of the zinc sulfide (ZnS) in different periodic forms ranging from the 3D bulk to the 2D hexagonal monolayer and their corresponding 1D zigzag single-walled nanotubes. To first order, the electronic wave function on the ground state was constructed using linear combinations of Gaussian-type functions at the DFT/B3LYP level. Then, the Raman and IR spectrum is computed by adopting a Coupled-Perturbed-Hartree–Fock/Kohn–Sham (CPHF/KS) approach. Cohesive, relaxation, and rolling energies, elastic and piezoelectric constants, electronic and nuclear contributions to the polarizability tensor, and nonlinear first and second-order hyperpolarizability tensor components are reported. Our study shows that 3D and 2D forms are stable and show semiconducting behavior, good piezoelectric responses, and fascinating linear and nonlinear optical properties. For 1D single-walled nanotubes, dynamic stability is observed only for the smallest (6,0) nanotubes. For n > 6, imaginary mode frequencies in the simulated IR and Raman spectra indicate dynamic instability. A scanning mode procedure along the largest imaginary vibrational mode is applied in order to determine the stable structures of the largest (14,0), (18,0) and (22,0) ZnS nanotubes. After that, no more imaginary phonon frequencies are detected in their vibrational spectra. Their potential energy surface contains two minima between a saddle point corresponding to a slightly distorted nanotube structure. Our study proves that the zinc sulfide nanostructures possess diverse physical properties so useful for potential applications in nanoelectronics and for nanodevices.

X-ray induced Coulomb explosion imaging of transient excited-state structural rearrangements in CS2

Structural imaging of transient excited-state species is a key goal of molecular physics, promising to unveil rich information about the dynamics underpinning photochemical transformations. However, separating the electronic and nuclear contributions to the spectroscopic observables is challenging, and typically requires the application of high-level theory. Here, we employ site-selective ionisation via ultrashort soft X-ray pulses and time-resolved Coulomb explosion imaging to interrogate structural dynamics of the ultraviolet photochemistry of carbon disulfide. This prototypical system exhibits the complex motifs of polyatomic photochemistry, including strong non-adiabatic couplings, vibrational mode couplings, and intersystem crossing. Immediately following photoexcitation, we observe Coulomb explosion signatures of highly bent and stretched excited-state geometries involved in the photodissociation. Aided by a model to interpret such changes, we build a comprehensive picture of the photoinduced nuclear dynamics that follows initial bending and stretching motions, as the reaction proceeds towards photodissociation.

Does the Fukushima nuclear accident still matter? Analysis of its mediated effects on five dimensions of nuclear power acceptance by using the parallel multiple mediator model

Although 10 years have passed since the Fukushima nuclear accident, it continues to greatly impact global energy policy and the acceptance of nuclear power. This study aims to empirically analyze the Fukushima accident's effects on five dimensions of nuclear power acceptance and the interactions of these effects with various determinants of nuclear power acceptance. We analyze survey data from 1020 Korean respondents and find that they remain highly worried about the Fukushima accident 10 years later. The Fukushima accident has negative impacts on the general acceptance of nuclear power, acceptance of nuclear power's contributions to addressing climate change, acceptance of high-level radioactive waste disposal sites, and acceptance of extensions of old nuclear power plants. However, the accident has a positive impact on the acceptance of denuclearization policies. Our parallel multiple mediator model shows that the Fukushima accident has only an indirect effect on general acceptance; this effect is negative and significant. The accident has a positive direct and indirect effect on acceptance of denuclearization policies but negative direct and indirect effects on the acceptability of high-level nuclear waste disposal and extensions of old nuclear power plants. Finally, we find a positive direct effect and a negative indirect effect of the accident on acceptance of nuclear power's contributions to addressing climate change. The latter is greater than the former, meaning that acceptance of nuclear power in the context of addressing climate change fell in response to the accident. In short, the Fukushima accident has different direct and indirect effects across different dimensions of nuclear power acceptance.

Experimental assessment of nuclear cross sections for the production of Tb radioisotopes with a medical cyclotron

155Tb is one of the most interesting radionuclides for theranostic applications. It is suitable for SPECT imaging and it can be used as a true diagnostic partner of the therapeutic 149Tb and 161Tb. Its production by proton irradiation using enriched 155Gd and 156Gd oxide targets is currently being investigated and represents a promising solution. To achieve the level of radionuclidic purity required in the clinical setting, the co-production of Tb impurities has to be minimized. For this purpose, an accurate knowledge of the cross sections of the nuclear reactions involved is of paramount importance. In this paper, we report on the assessment of cross sections of the reactions 154Gd(p,xn)153,154,154m1,154m2Tb, 155Gd(p,xn)154,154m1,154m2,155Tb, 156Gd(p,xn)155,156Tb and 157Gd(p,2n)156Tb derived with a specific data analysis procedure developed by our group. This method allows to disentangle the nuclear contributions from the production cross section by inverting linear systems of equations and it requires the measurement of the cross sections from as many materials as the reactions involved in the production of the radionuclide under study. For this purpose, the experimental data previously measured by our group at the Bern medical cyclotron by irradiating natural Gd2O3, enriched 155Gd2O3 and enriched 156Gd2O3 targets were used. For some of these nuclear reactions, cross sections were assessed for the first time. On the basis of our findings, production yield and purity can be calculated for any kind of isotopic composition of the enriched material.

Stability of a two-electron system under pressure confinement: structural and quantum information theoretical analysis

The stability of a two-electron Zee system trapped inside an impenetrable spherical cavity is analyzed using an explicitly correlated multi-exponent Hylleraas-type basis set in the framework of the Ritz variational method. The wave function is considered to be consistent with Dirichlet’s boundary condition. Four different values are considered, where denotes the critical nuclear charge beyond which the system is embedded in a discrete positive energy continuum due to the impenetrable nature of the cavity. The energy contribution due to the total correlation (in the presence of both radial and angular correlation) effect, the radial correlation limit, and the angular correlation limit are also studied in detail. The thermodynamic pressure felt by the two-electron Zee system inside the cavity is estimated, and a formula replicating the behavior between the pressure and volume of the cavity is deduced by a fitting procedure. Different geometrical properties, e.g. radial moments (, , , , ; p = ), angular moments (, ), and related important physical quantities, are determined. The variation of Kirkwood and Buckingham polarizabilities w.r.t. the pressure felt by the two-electron Zee system is analyzed. A one-electron radial density is estimated for each pair of (), which has been employed to generate the electrostatic potential as well as different information theoretical measures like Shannon entropy, Fisher entropy, Rényi entropy, Tsallis entropy, and Onicescu informational energy. The chosen information theoretical measures have been found to be sensitive tools for describing changes in the electronic structure due to spatial confinement. An interesting interplay between the electronic and nuclear contribution to the classical electrostatic potential is observed, leading to a shift in the position of its characteristic minimum due to compression. Wherever possible, a comparison is made in order to ascertain the high accuracy of our numerical results. The procedure of analytic evaluation of the integrals needed to estimate the atomic properties under consideration is discussed in detail.

Nuclear medicine contribution to precision surgery in breast cancer

Nuclear medicine has significantly contributed to precision surgery in breast cancer in the past decades. Radioguided surgery (RGS) has enabled sentinel node (SN) biopsy in assessing regional nodal involvement modifying the management of patients with early breast cancer. For the axilla the SN procedure has resulted in fewer complications and better quality of life when compared with axillary lymph node dissection. Originally, SN biopsy principally concerned cT 1-2 tumours without evidence of axillary lymph node metastases. However, in last years SN biopsy is also being offered to patients with large or multifocal tumours, ductal carcinoma in situ, ipsilateral breast cancer relapse, and to patients receiving neoadjuvant systemic treatment (NST) for breast sparing surgery. Parallel to this evolution various scientific associations are trying to homogenise issues such as radiotracer choice, breast injection site, preoperative imaging standardisation and SN biopsy timing in relation to NST as well as management of non-axillary SN metastasis (e.g. internal mammary chain). Additionally, RGS is currently used to accomplish primary breast tumour excision either by intralesional radiocolloid injection or by radioactive iodine seed implantation which is also employed to target metastatic axillary lymph nodes. This latter procedure contributes to manage the node-positive axilla in combination with 18F-FDG PET/CT in an effort to tailor systemic and loco regional treatment.

Structural and magnetic phase transitions in Fe3Ge : A neutron diffraction study

A detailed neutron diffraction study of a stoichiometric ${\mathrm{Fe}}_{3}\mathrm{Ge}$ alloy with different initial states in a wide temperature range (up to 1000 K) made it possible to accurately reveal the features of magnetic and structural phase transformations in it. The use of complementary x-ray diffraction and analysis of neutron diffraction patterns by the Rietveld method allowed reliably separating the nuclear and magnetic contributions to the intensity of the diffraction peaks and performing refinement of the ${\mathrm{Fe}}_{3}\mathrm{Ge}$ magnetic state characteristics. Both main phases appearing in ${\mathrm{Fe}}_{3}\mathrm{Ge}$ are ferromagnetic with ${T}_{\mathrm{C}}=629$ K (hexagonal, $D{0}_{19}$) and ${T}_{\mathrm{C}}=714$ K (cubic, $L{1}_{2}$). In $D{0}_{19}$, the presence of a spin-flip transition (${T}_{\mathrm{sf}}=385$ K) was confirmed and the temperature dependence of the components of magnetic moment along the hexagonal axis and in the basal plane was obtained. It was shown that the transformation between ordered $L{1}_{2}$ and $D{0}_{19}$ structural states, predicted by the equilibrium-phase diagram, includes three steps: two diffusional stages ($L{1}_{2}\ensuremath{\rightarrow}A1, A3\ensuremath{\rightarrow}D{0}_{19}$) and one displacive stage ($A1\ensuremath{\rightarrow}A3$). The obtained structural data suggest that in Fe-Ge, as well as in Fe-Ga alloy, direct transitions between ordered phases are impossible. They should include a transition between disordered states.

A Free Energy Decomposition Analysis: Insight into Binding Thermodynamics from Absolutely Localized Molecular Orbitals.

Traditional energy decomposition analysis (EDA) methods can provide an interpretive decomposition of non-covalent electronic binding energies. However, by definition, they neglect entropic effects and nuclear contributions to the enthalpy. With the objective of revealing the chemical origins of trends in free energies of binding, we introduce the concept of a Gibbs decomposition analysis (GDA) by coupling the absolutely localized molecular orbital treatment of electrons in non-covalent interactions with the simplest possible quantum rigid rotor-harmonic oscillator treatment of nuclear motion at finite temperature. The resulting pilot GDA is employed to decompose enthalpic and entropic contributions to the free energy of association of the water dimer, fluoride-water dimer, and water binding to an open metal site in the metal-organic framework Cu(I)-MFU-4l. The results show enthalpic trends that generally track the electronic binding energy and entropic trends that reveal the increasing price of loss of translational and rotational degrees freedom with temperature.

A Glimpse into Chromatin Organization and Nuclear Lamina Contribution in Neuronal Differentiation.

During embryonic development, stem cells undergo the differentiation process so that they can specialize for different functions within the organism. Complex programs of gene transcription are crucial for this process to happen. Epigenetic modifications and the architecture of chromatin in the nucleus, through the formation of specific regions of active as well as inactive chromatin, allow the coordinated regulation of the genes for each cell fate. In this mini-review, we discuss the current knowledge regarding the regulation of three-dimensional chromatin structure during neuronal differentiation. We also focus on the role the nuclear lamina plays in neurogenesis to ensure the tethering of the chromatin to the nuclear envelope.

3C 120 Disk/Corona vs. Jet Variability in X-rays

The 3C120 (Mrk 1506, UGC 03087, Mrk 9014) is a type 1 Seyfert (Sy1)/broad-line radio galaxy (BLRG) with intriguing variable jet activity featuring “dip” and “outburst” phases. Significant X-ray observational datasets have been collected for 3C120 by INTEGRAL, XMM-Newton, SWIFT, Suzaku, and other X-ray observational facilities. The overall X-ray spectrum of 3C 120 is too soft for typical radio-loud AGN, likely due to both variable spectral shape and jet contamination. Separating the “jet base” and nuclear (disc/corona) counterparts in the X-ray spectrum of 3C 120 can provide us with the possibility to investigate its variability in a more detailed way. Our objectives are to estimate separately the time variations of the accretion disc/corona and SSC/IC jet emission counterparts in the 3C 120 X-ray spectra and to analyze the physical state of the nucleus during different phases. Here, we attempt to use the connections between the synchrotron radio- and X-ray SSC/IC jet spectra and their photon indices and the dependence between the nuclear continuum and Fe-K iron luminescent line emission near 6.4 keV to separate the nuclear and jet base contributions to the total X-ray continuum. Using the X-ray observational dataset of 3C 120, we obtained separated fluxes that were interpreted as originating from the nucleus (disc/corona) and non-thermal SSC/IC jet base contributions. After this component separation, we identified the accretion disc/corona and jet states during different phases and compared them with the “jet/disk cycle” (Lohfink) and “magnetic plasmoid reconnection” (Shukla/Manheim) models.

Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon.

To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of the 5g-4f and 5f- 4d transitions (BSQED contribution of 2.4 and 5.2eV, respectively) of muonic neon atoms in the low-pressure gas phase without bound electrons. Muonic atoms have been recently proposed as an alternative to few-electron high-Z ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined the 5g_{9/2}- 4f_{7/2} transition energy to be 6297.08±0.04(stat)±0.13(syst) eV using superconducting transition-edge sensor microcalorimeters (5.2-5.5eV FWHM resolution), which agrees well with the most advanced BSQED theoretical prediction of 6297.26eV.