Nuclear Distortion Research Articles

Emerin preserves stem cell survival through maintenance of centrosome and nuclear lamina structure.

Drosophila female germline stem cells (GSCs) complete asymmetric mitosis in the presence of an intact, but permeable, nuclear envelope and nuclear lamina (NL). This asymmetric division requires a modified centrosome cycle, wherein mitotic centrosomes with mature pericentriolar material (PCM) embed in the NL and interphase centrosomes with reduced PCM leave the NL. This centrosome cycle requires emerin, a NL protein critical for GSC survival and germ cell differentiation. In emerin mutants, interphase GSCs centrosomes retain excess PCM, remain embedded in the NL and nucleate microtubule asters at positions of NL distortion. Here, we address contributions of abnormal interphase centrosomes to GSC loss. Remarkably, reducing interphase PCM in emerin mutants rescues GSC survival and partially restores germ cell differentiation. Direct tests of effects of abnormal centrosomes were achieved by expression of constitutively active Polo kinase that drove enlargement of interphase centrosomes in wild type GSCs. Notably, these conditions failed to alter NL structure or decrease GSC survival. However, coupling enlarged interphase centrosomes with nuclear distortion promoted GSC loss. These studies establish that emerin maintains centrosome structure to preserve stem cell survival.

Maintenance of germline stem cell homeostasis despite severe nuclear distortion

Stem cell loss in aging and disease is associated with nuclear deformation. Yet, how nuclear shape influences stem cell homeostasis is poorly understood. We investigated this connection using Drosophila germline stem cells, as survival of these stem cells is compromised by dysfunction of the nuclear lamina, the extensive protein network that lines the inner nuclear membrane and gives shape to the nucleus. To induce nuclear distortion in germline stem cells, we used the GAL4-UAS system to increase expression of the permanently farnesylated nuclear lamina protein, Kugelkern, a rate limiting factor for nuclear growth. We show that elevated Kugelkern levels cause severe nuclear distortion in germline stem cells, including extensive thickening and lobulation of the nuclear envelope and nuclear lamina, as well as alteration of internal nuclear compartments. Despite these changes, germline stem cell number, proliferation, and female fertility are preserved, even as females age. Collectively, these data demonstrate that disruption of nuclear architecture does not cause a failure of germline stem cell survival or homeostasis, revealing that nuclear deformation does not invariably promote stem cell loss.

Resonance Raman intensity analysis of photoactive metal-organic frameworks.

Metal-organic frameworks (MOFs) are promising candidate materials for photo-driven processes. Their crystalline and tunable structure makes them well-suited for placing photoactive molecules at controlled distances and orientations that support processes such as light harvesting and photocatalysis. In order to optimize their performance, it is important to understand how these molecules evolve shortly after photoexcitation. Here, we use resonance Raman intensity analysis (RRIA) to quantify the excited state nuclear distortions of four modified UiO-68 MOFs. We find that stretching vibrations localized on the central ring within the terphenyl linker are most distorted upon interaction with light. We use a combined computational and experimental approach to create a picture of the early excited state structure of the MOFs upon photoactivation. Overall, we show that RRIA is an effective method to probe the excited state structure of photoactive MOFs and can guide the synthesis and optimization of photoactive designs.

Abstract 3138: Atheroprone Flow, Aging, And Oxysterols Impair Endothelial Cell Nuclear Health Via Disruption Of Autoregulatory Perinuclear Cytoskeletal Dynamics

The vascular hemodynamic environment plays a well-known role with progressive pathological conditions such as atherosclerosis, hypercholesterolemia, and aging. Our lab has previously shown that the exposure of oxysterols to endothelial cells (ECs) causes increased cell stiffening. This stiffening effect is compounded when the hemodynamic environment changes from atheroprotective laminar flow to atheroprone oscillatory flow. The increasing EC stiffening demonstrates that these disruptive effects significantly alter cellular biomechanics. The complexity of events associated with these altered biomechanical states leaves many questions unanswered about spatiotemporal changes in the biomechanical structures of endothelial cells exposed to a varying hemodynamic environment and oxysterols. To address this void, we observed the effects of 7-Ketocholesterol exposure (a major oxysterol) on the primary cytoskeletal/biomechanical components (F-actin, Microtubules, Intermediate Filaments, etc.) of human aortic endothelial cells during various time points of laminar/oscillatory flow conditions through a combination of sophisticated multiplexed 6-color labeling, ultra-high resolution 3D microscopy, 3D computer vision, and machine learning. Additionally, we applied these techniques to extracted aortic tissues from young and aged mice (on low fat diet vs high fat diet) and focused on obtaining information from both the laminar flow areas (descending aorta) and the oscillatory flow areas (aortic arch). Our findings demonstrate that oxysterol exposure and aging cause significant remodeling & alteration of crucial endothelial cytoskeletal/biomechanical components and that these alterations are unique to each combinatorial condition. Notably, we find that cytoskeletal remodeling associated with endothelial stiffening is accompanied by major nuclear distortion, a hallmark of aging and senescence which subsequently causes DNA damage and genomic instability. We also find that this nuclear distortion is driven by dynamic biomechanical changes and mediated by the hemodynamic environment, where atheroprotective flow promotes cytoskeletal configurations protecting the nuclei, and atheroprone flow promotes cytoskeletal configurations that leave the nuclei unprotected.

D-Tetramethrin causes zebrafish hepatotoxicity by inducing oxidative stress and inhibiting cell proliferation

d-Tetramethrin is one of the main components of mosquito control products, and is widely used for the control of dengue fever and insecticide production. Due to its widespread use, d-tetramethrin is a ubiquitous environmental pollutant and poses potential risks to human health. However, the effects of d-tetramethrin on liver morphology and function are not clearly established. In this study, we used zebrafish as an animal model to analyze the acute and chronic effects of d-tetramethrin exposure on the liver. We exposed zebrafish larvae and adults to different concentrations of d-tetramethrin and examined the impact of d-tetramethrin on lipid and glycogen metabolism, cellular properties, oxidative stress, cell proliferation, and apoptosis in the liver. We also analyzed transcriptional changes in genes related to apoptosis, inflammation, and cell proliferation using qPCR. Zebrafish exposed to d-tetramethrin exhibited severe liver damage, as evidenced by the presence of vacuoles and nuclear distortion in liver cells. The liver area in zebrafish larvae of the treatment group was significantly smaller than that of the control group. Significant lipid accumulation and decreased glycogen levels were observed in the livers of both zebrafish larvae and adults exposed to d-tetramethrin. Furthermore, d-tetramethrin exposure induced apoptosis and inflammation in zebrafish embryos. Additionally, d-tetramethrin caused liver damage, metabolic dysfunction, and impaired liver function. These results suggest that d-tetramethrin induces liver toxicity in zebrafish, by inducing oxidative stress and inhibiting cell proliferation.

The nuclear lamina is required for proper development and nuclear shape distortion in tomato.

The nuclear lamina in plant cells is composed of plant-specific proteins, including Nuclear Matrix Constituent Proteins (NMCPs), which have been postulated to be functional analogs of lamin proteins that provide structural integrity to the organelle and helps stabilize the three-dimensional organization of the genome. Using genomic editing, we generated alleles for the three genes encoding NMCPs in cultivated tomato (Solanum lycopersicum) to determine if the consequences of perturbing the nuclear lamina in this crop species were similar or distinct from those observed in the model Arabidopsis thaliana. Loss of the sole NMCP2-class protein was lethal in tomato but is tolerated in Arabidopsis. Moreover, depletion of NMCP1-type nuclear lamina proteins leads to distinct developmental phenotypes in tomato, including leaf morphology defects and reduced root growth rate (in nmcp1b mutants), compared to cognate mutants in Arabidopsis. These findings suggest that the nuclear lamina interfaces with different developmental and signaling pathways in tomato compared to Arabidopsis. At the subcellular level, however, tomato nmcp mutants resembled their Arabidopsis counterparts in displaying smaller and more spherical nuclei in differentiated cells. This result argues that the plant nuclear lamina facilitates nuclear shape distortion in response to forces exerted on the organelle within the cell.

Triple differential cross sections for single ionization of an atom by bare ion impact

We present triple differential cross sections (TDCSs) for single ionization of atoms by proton and highly charged bare ions impact by means of the three-body formalism of the first Born, two-Coulomb wave and three-Coulomb (3C) wave (3CW) methods, respectively. The TDCS has been calculated both in the scattering and perpendicular planes. The purpose of this work is to investigate the validity of different methods as well as the role of interaction between projectile and residual-target-ion in the final state for weak perturbation strength with low electron emission energy at several momentum transfers. By comparing our calculations with experimental data, overall, the 3CW predicts better agreement with experiments than other calculations in the scattering plane. In the perpendicular plane, all calculations deviate from experimental data with increasing transverse momentum transfer for p − He collision. At low momentum transfer, the location of binary peak obtained by the first Born approximation calculation is well established with the experiment for proton impact. On the other hand, the 3CW model is in much better agreement with experiments, both in absolute values and peak position for highly charged impact. Finally, the strong influence of the internuclear Coulomb distortion on TDCS has been observed at low and intermediate momentum transfer.

Arf-like Protein 2 (ARL2) Controls Microtubule Neogenesis during Early Postnatal Photoreceptor Development.

Arf-like protein 2 (ARL2) is a ubiquitously expressed small GTPase with multiple functions. In a cell culture, ARL2 participates with tubulin cofactor D (TBCD) in the neogenesis of tubulin αβ-heterodimers, the building blocks of microtubules. To evaluate this function in the retina, we conditionally deleted ARL2 in mouse retina at two distinct stages, either during the embryonic development (retArl2-/-) or after ciliogenesis specifically in rods (rodArl2-/-). retArl2-/- retina sections displayed distorted nuclear layers and a disrupted microtubule cytoskeleton (MTC) as early as postnatal day 6 (P6). Rod and cone outer segments (OS) did not form. By contrast, the rod ARL2 knockouts were stable at postnatal day 35 and revealed normal ERG responses. Cytoplasmic dynein is reduced in retArl2-/- inner segments (IS), suggesting that dynein may be unstable in the absence of a normal MTC. We investigated the microtubular stability in the absence of either ARL2 (retARL2-/-) or DYNC1H1 (retDync1h1-/-), the dynein heavy chain, and found that both the retArl2-/- and retDync1h1-/- retinas exhibited reduced microtubules and nuclear layer distortion. The results suggest that ARL2 and dynein depend on each other to generate a functional MTC during the early photoreceptor development.

Regulation of mesenchymal stem cell osteogenic potential via microfluidic manipulation of microcarrier surface curvature

Microsphere-carriers have gained great interests as three-dimensional substrates for cultivation/expansion of tissue cells, required by cell-based therapy. However, how the microsphere curvature affects the cell proliferation/differentiation as well as the underlying signaling pathway of stem cells, and how to consequently regulate those cellular functionalities via manipulating microcarrier surface curvature, still remain to be explored. The current study was thus designed to develop a microfluidic manipulation technology to precisely control poly (lactic-co-glycolic) acid (PLGA) microsphere surface curvature, and subsequently to investigate the cellular responses and responding pathways of rat bone mesenchymal stem cells (BMSCs) cultured on these microspheres of predetermined curvature. A microfluidic device was developed to produce mono-distributed PLGA microspheres of diameters ranging from 52 µm to 250 µm, corresponding to curvatures (κ) from 1/26 µm−1 to 1/125 µm−1. BMSCs attachment and proliferation was evaluated on them and the one of κ = 1/82.5 µm−1 was shown to provide the most suitable microenvironment for cells to grow and undergo osteogenic differentiation. It was even found that F-actin cytoskeletal organization, nuclear distortion and expression of Lamin A were significantly enhanced by cells on the microcarriers of κ = 1/82.5 µm−1. Furthermore, a long non-coding RNA named lnc-LMNA, was found in this study to be the key factor associated with Lamin A to regulate osteogenic differentiation of BMSCs on spherical substrates. The current study thus provides a smart manipulation technology via microfluidic-manufacturing microcarriers to regulate cell functionalities, thereby enhancing desired therapeutic outcomes of cell-based regeneration or repair.

Benzyl Alcohol Increases Diffusion Limit of Nuclear Membrane in Saccharomyces cerevisiae Cells

Objective: Fungi are invasive species responsible for infections in many people around the world and which severely affect the immune system. The opportunistic pathogenic species, such as Candida species and Aspergillus fumigatus, can cause death in people with weakened immune systems. Natural medicines derived from plants are often used to treat fungal diseases. In connection with our efforts to unearth possible cellular targets of antimicrobial agents, in this study, we aimed to determine the functional consequences of benzyl alcohol treatment on the nuclear membrane. Materials and Methods: We analysed the nuclear membrane distortions caused by benzyl alcohol in Saccharomyces cerevisiae cells using Nup49-GFP reporter strain. We also studied cellular distributions of various fluorescently tagged nuclearcytoplasmic shuttling proteins to determine any functional disturbances in nuclear pore complexes upon benzyl alcohol treatment. Localization of 51.5 kDa protein LexA-NES-GFP and 61.8 kDa protein Pho4(Δ157-164)-GFP to the nucleus in yeast cells was key for evaluating the effect upon diffusion limit of pores. Results: By analyzing the distribution of fluorescently tagged nuclear localization signal or nuclear export signals bearing reporter proteins between the nucleus and cytoplasm, we have shown that the nuclear membrane becomes leaky upon benzyl alcohol treatment. Conclusion: The diffusion limit across the nuclear membrane in yeast cells is increased upon benzyl alcohol treatment. We believe that these findings not only increase our understanding of the mode of action of benzyl alcohol bearing antifungal agents, but also help widening their use.

In Vitro and In Vivo Evaluation of a Cyclic LyP-1-Modified Nanosystem for Targeted Endostatin Delivery in a KYSE-30 Cell Xenograft Athymic Nude Mice Model.

This work investigated the use of LyP-1 as a homing peptide for p32 receptor targeting on the surface of an endostatin (ENT)-loaded chitosan-grafted nanosystem intended for intracellular delivery of ENT and mitochondrial targeting in a squamous cell carcinoma (SCC) cell line (KYSE-30) model. The angiogenic factors for VEGF-C and MMP2 were assessed with in vivo evaluation of the nanosystem upon ENT release and tumor necrosis in nude mice with a KYSE-30 cell xenograft. The LyP-1-modified nanosystem revealed a three-fold decrease in proliferation at 1000 µg/mL compared with the control and facilitated receptor-mediated cellular uptake and internalization. In addition, targeting of the Lyp-1-functionalized nanosystem to mitochondrial and nuclear proteins in vitro and in vivo was achieved. Up to 60% inhibition of KYSE-30 cell migration was observed and the expressions of VEGF-C and MMP-2 as angiogenic markers were reduced 3- and 2-fold, respectively. A marked reduction in tumor mass was recorded (43.25%) with the control, a 41.36% decrease with the nanoparticles and a 61.01% reduction with the LyP-1-modified nanosystem following treatment in mice. The LyP-1-functionalized nanosystem targeted tumor lymphatics, instigated nuclear rupture and mitochondrial distortion, and decreased cell proliferation and migration with inhibition of VEGF-C and MMP2 expression.

Pseudo Jahn−Teller Origin of the Proton Tunneling in Zundel Cation Containing Water Clusters

The pseudo Jahn–Teller (PJT) origin of the proton transfer barrier in the Zundel cation at different O–O distances and in an H5O2+(H2O)4 cluster is revealed by means of ab initio calculations of their electronic structures and the adiabatic potential energy curves. The vibronic constants in this approach were estimated by fitting the ab initio calculated adiabatic potential to its analytical expression. It is shown also that the high-symmetry nuclear configurations ofproton-centered water clusters of the type H+(H2O)n (n = 6, 4, 3) are unstable with respect to the low-symmetry nuclear distortions leading to forming the dihydronium cation H5O2+ and the appropriate number of water molecules: H2n + 1On+ → (n – 2)H2O + H5O2+. The reason for this instability and the subsequent decay is the PJT coupling between the ground and excited electronic states.

Anticancer potential of Pd and Pt metallo-macrocycles of phosphines and 4,4΄-dipyridyldiselenide

Reactions of [M(P∩P)(X)2] (M = Pd, Pt; X = NO3, OTf) and 4,4΄-dipyridyldiselenide yielded metallo-macrocyclic complexes [M(P∩P)(4,4΄-py2Se2)]n(X)2n capped by wide-bite-angle diphosphines (P∩P = dppf, Xantphos), which were characterized by NMR spectroscopy and ESI mass spectrometry. The X-ray analysis confirm the dimeric structure of [Pt(dppf)(4,4΄-py2Se2)]2(NO3)4 consisting of two Pt(II) centers bridged by 4,4΄-dipyridyldiselenides holding Pt-N bonds. In vitro cytotoxic activity of the complexes along with the previously synthesized [Pt(PEt3)2(4,4′-py2Se2)]n(OTf)2n was evaluated by MTT and clonogenic assay employing breast (MCF7), lung (A549), bone (U2OS) and ovarian (SKOV3) cancer cell lines. The results revealed the potent anticancer activity of these compounds. DNA damage was assessed by γ-H2AX, revealing that all the complexes induced DNA damage in the breast cancer cells. Further they also induced formation of micronuclei and other nuclear distortions. The complex [Pt(PEt3)2(4,4′-py2Se2)]n(OTf)2n has induced more nuclear abnormalities and exhibited higher anticancer activity than cisplatin.

Correspondence between isoscalar monopole strengths and $\alpha$ inelastic cross sections on 24Mg

Abstract The correspondence between the isoscalar monopole (IS0) transition strengths and $\alpha$ inelastic cross sections, the $B({\rm IS0})$–$(\alpha,\alpha')$ correspondence, is investigated for $^{24}$Mg($\alpha,\alpha'$) at 130 and 386 MeV. We adopt a microscopic coupled-channel reaction framework to link structural inputs, diagonal and transition densities, for $^{24}$Mg obtained with antisymmetrized molecular dynamics to the ($\alpha,\alpha'$) cross sections. We aim at clarifying how the $B({\rm IS0})$–$(\alpha,\alpha')$ correspondence is affected by the nuclear distortion, the in-medium modification to the nucleon–nucleon effective interaction in the scattering process, and the coupled-channel effect. It is found that these effects are significant and the explanation of the $B({\rm IS0})$–$(\alpha,\alpha')$ correspondence in the plane wave limit with the long-wavelength approximation, which is often used, makes no sense. Nevertheless, the $B({\rm IS0})$–$(\alpha,\alpha')$ correspondence tends to remain because of a strong constraint on the transition densities between the ground state and the $0^+$ excited states. The correspondence is found to hold at 386 MeV with an error of about 20%–30%, while it is seriously compromised at 130 MeV, mainly by the strong nuclear distortion. It is also found that when a $0^+$ state that has a different structure from a simple $\alpha$ cluster state is considered, the $B({\rm IS0})$–$(\alpha,\alpha')$ correspondence becomes less valid. For a quantitative discussion on the $\alpha$ clustering in $0^+$ excited states of nuclei, a microscopic description of both the structure and reaction parts will be necessary.

Proton-induced deuteron knockout reaction as a probe of an isoscalar proton-neutron pair in nuclei

The isoscalar $pn$ pair is expected to emerge in nuclei having the similar proton and neutron numbers but there is no clear experimental evidence for it. We aim to clarify the correspondence between the $pn$ pairing strength in many-body calculation and the triple differential cross section (TDX) of proton-induced deuteron knockout ($p,pd$) reaction on $^{16}$O. The radial wave function of the isoscalar $pn$ pair with respect to the center of $^{16}$O is calculated with the energy density functional (EDF) approach and is implemented in the distorted wave impulse approximation (DWIA) framework. The $pn$ pairing strength $V_0$ in the EDF calculation is varied and the corresponding change in the TDX is investigated. A clear $V_0$ dependence of the TDX is found for the $^{16}$O($p,pd$)$^{14}$N($1_2^+$) at $101.3$ MeV. The nuclear distortion is found to make the $V_0$ dependence stronger. Because of the clear $V_0$-TDX correspondence, the ($p,pd$) reaction will be a promising probe for the isoscalar $pn$ pair in nuclei. For quantitative discussion, further modification of the description of the reaction process will be necessary.

Electronic excitation in graphene under single-particle irradiation

Single-particle irradiation is a typical condition in space applications, which could be detrimental for electronic devices through processes such as single-event upset or latch-up. For functional devices made of few-atom-thick monolayers that are entirely exposed to the environment, the irradiation effects could be manifested through localized or delocalized electronic excitation, in addition to lattice defect creation. In this work, we explore the single-H irradiation effects on bare or coated graphene monolayers. Real-time time-dependent density functional theory-based first-principles calculation results elucidate the evolution of charge densities in the composite system, showing notable charge excitation but negligible charge deposition. A hexagonal boron nitride coating layer does not protect graphene from these processes. Principal component analysis demonstrates the dominance of localized excitation accompanied by nuclear motion, bond distortion and vibration, as well as a minor contribution from delocalized plasmonic excitation. The significance of coupled electron–ion dynamics in modulating the irradiation processes is identified from comparative studies on the spatial and temporal patterns of excitation for unconstrained and constrained lattices. The stopping power or energy deposition is also calculated, quantifying the dissipative nature of charge density excitation. This study offers fundamental understandings of the single-particle irradiation effects on optoelectronic devices constructed from low-dimensional materials, and inspires unconventional techniques to excite the electrons and ions in a controllable way.

Micropatterned Surfaces Expose the Coupling between Actin Cytoskeleton-Lamin/Nesprin and Nuclear Deformability of Breast Cancer Cells with Different Malignancies.

Mechanotransduction proteins transfer mechanical stimuli through nucleo-cytoskeletal coupling and affect the nuclear morphology of cancer cells. However, the contribution of actin filament integrity has never been studied directly. It is hypothesized that differences in nuclear deformability of cancer cells are influenced by the integrity of actin filaments. In this study, transparent micropatterned surfaces as simple tools to screen cytoskeletal and nuclear distortions are presented. Surfaces decorated with micropillars are used to culture and image breast cancer cells and quantify their deformation using shape descriptors (circularity, area, perimeter). Using two drugs (cytochalasin D and jasplakinolide), actin filaments are disrupted. Deformation of cells on micropillars is decreased upon drug treatment as shown by increased circularity. However, the effect is much smaller on benign MCF10A than on malignant MCF7 and MDAMB231 cells. On micropatterned surfaces, molecular analysis shows that Lamin A/C and Nesprin-2 expressions decreased but, after drug treatment, increased in malignant cells but not in benign cells. These findings suggest that Lamin A/C, Nesprin-2 and actin filaments are critical in mechanotransduction of cancer cells. Consequently, transparent micropatterned surfaces can be used as image analysis platforms to provide robust, high throughput measurements of nuclear deformability of cancer cells, including the effect of cytoskeletal elements.

Vibronic resonance is inadequately described by one-particle basis sets

Vibrational-electronic (vibronic) resonance and its possible role in energy and charge transfer have been experimentally and theoretically investigated in several photosynthetic proteins. Using a dimer modeled on a typical photosynthetic protein, we contrast the description of such excitons provided by an exact basis set description, as opposed to a basis set with reduced vibrational dimensionality. Using a reduced analytical description of the full Hamiltonian, we show that in the presence of vibrational excitation both on electronically excited as well as unexcited sites, constructive interference between such basis states causes vibronic coupling between excitons to become progressively stronger with increasing quanta of vibrational excitation. This effect leads to three distinguishing features of excitons coupled through a vibronic resonance, which are not captured in basis sets that restrict ground state vibrations: (1) the vibronic resonance criterion itself, (2) vibronically assisted perfect delocalization between sites even though purely electronic mixing between the sites is imperfect due to energetic disorder, and (3) the nuclear distortion accompanying vibronic excitons becoming increasingly larger for resonant vibronic coupling involving higher vibrational quanta. In terms of spectroscopically observable limitations of reduced basis set descriptions of vibronic resonance, several differences are seen in absorption and emission spectra but may be obscured on account of overwhelming line broadening. However, we show that several features such as vibronic exciton delocalization and vibrational distortions associated with electronic excitations, which ultimately dictate the excited state wavepacket motions and relaxation processes, are fundamentally not described by basis sets that restrict ground state vibrations.

Determining B(E1) distributions of weakly bound nuclei from breakup cross sections using Continuum Discretized Coupled Channels calculations. Application to 11Be

A novel method to extract the B(E1) strength of a weakly bound nucleus from experimental Coulomb dissociation data is proposed. The method makes use of continuum discretized coupled channels (CDCC) calculations, in which both nuclear and Coulomb forces are taken into account to all orders. This is a crucial advantage with respect to the standard procedure based on the Equivalent Photon Method (EPM) which does not properly take into account nuclear distortion, higher order coupling effects, or Coulomb-nuclear interference terms. The systematic and statistical uncertainties of this procedure are evaluated. The procedure is applied to the 11Be nucleus using two sets of available experimental data at different energies, for which seemingly incompatible B(E1) have been reported using the EPM. We show that the present procedure gives consistent B(E1) strengths, thus solving the aforementioned long-standing discrepancy between the two measurements.

DSP Implementation of Neutron Radiation Detection Based on Kalman Filter

Aiming at the situation of nuclear neutron pulse count distortion and low measurement accuracy, a digital processing chip and Kalman filter are designed to replace the traditional hardware filtering method. The system uses TMS320F28335 as the main control chip, and takes advantage of the DSP-specific digital signal processing chip. After using the extended Kalman filter to reduce the noise and filter the pulse neutron count, the experiment proves that the nuclear pulse neutron count measurement after the extended Kalman filter process is stable, and the measurement accuracy has been significantly improved. The overall structure and working principle of the system are introduced, and specific hardware and software design schemes are given.