Differential Phase Research Articles

Murine erythroid differentiation kinetics in vivo under normal and anemic stress conditions

AbstractOur current understanding of the kinetics and dynamics of erythroid differentiation is based almost entirely on the ex vivo expansion of cultured hematopoietic progenitor cells. In this study, we used an erythroid-specific, inducible transgenic mouse line to investigate for the first time, the in vivo erythroid differentiation kinetics under steady-state conditions. We demonstrated that bipotent premegakaroycyte/erythroid (PreMegE) progenitor cells differentiate into erythroid–committed proerythroblast/basophilic erythroblasts (ProBasoE) after 6.6 days under steady-state conditions. During this process, each differentiation phase (from PreMegE to precolony forming unit-erythroid [PreCFU-E], PreCFU-E to CFU-E, and CFU-E to ProBasoE) took ∼2 days in vivo. Upon challenge with 5-flurouracil (5-FU), which leads to the induction of stress erythropoiesis, erythroid maturation time was reduced from 6.6 to 4.7 days. Furthermore, anemia induced in 5-FU-treated mice was shown to be due not only to depleted bone marrow erythroid progenitor stores but also to a block in reticulocyte exit from the bone marrow into the circulation, which differed from the mechanism induced by acute blood loss.

Imaging the dynamic influence of functional groups on metal-organic frameworks

Metal-organic frameworks (MOFs) with different functional groups have wide applications, while the understanding of functionalization influences remains insufficient. Previous researches focused on the static changes in electronic structure or chemical environment, while it is unclear in the aspect of dynamic influence, especially in the direct imaging of dynamic changes after functionalization. Here we use integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM) to directly ‘see’ the rotation properties of benzene rings in the linkers of UiO-66, and observe the high correlation between local rigidity and the functional groups on the organic linkers. The rigidity is then correlated to the macroscopic properties of CO2 uptake, indicating that functionalization can change the capability through not only static electronic effects, but also dynamic rotation properties. To the best of our knowledge this is the first example of a technique to directly image the rotation properties of linkers in MOFs, which provides an approach to study the local flexibility and paves the way for potential applications in capturing, separation and molecular machine.

Regulation of mitotic clonal expansion and thermogenic pathway are involved in the antiadipogenic effects of cyanidin-3-O-glucoside.

Introduction: Obesity is a metabolic disease with an increase both in cell size (hypertrophy) and in cell number (hyperplasia) following differentiation of new adipocytes. Adipogenesis is a well-orchestrated program in which mitotic clonal expansion (MCE) occurs in the early step followed by the late terminal differentiation one. Methods: Aim of the study was to evaluate the in vitro effects of cyanidin-3-O-glucoside (C3G), an anthocyanin present in many fruits and vegetables, in the early or late phase of 3T3-L1 preadipocytes differentiation. Results: C3G exposure in the early phase of adipogenesis process induced a more marked reduction of CCAAT/enhancer-binding protein-β (C/EBPβ), peroxisome proliferator-activated receptor γ (PPAR-ɣ) and fatty acid synthase (Fasn) expression than late phase exposure and these effects were associated to a reduced MCE with cell cycle arrest at G0/G1 phase via p21 expression. Furthermore, C3G exposure during the early phase activated AMP-activated protein kinase (AMPK) pathway better than in the late phase promoting the enhancement of beige-like adipocytes. In fact, C3G induced thermogenic biomarkers uncoupling protein-1 (Ucp1) and peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (Pgc1) and these effects were more evident during early phase exposure. Conclusion: Our data demonstrate that C3G reduces the terminal adipogenic process affecting the early phase of differentiation and inducing a thermogenic program.

Quantification of porosity in composite plates using planar X-ray phase contrast imaging

The application of planar Edge-Illumination X-ray Phase-Contrast imaging (EI-XPCi) for the non-destructive quantification of porosity in carbon fiber reinforced polymer (CFRP) specimens, a significant concern in aerospace applications, was investigated. The method enables fast, planar (2D) scans providing access to large samples. A set of woven CFRP plates with porosity content ranging from 0.7% to 10.7% was examined. In addition to standard X-ray attenuation, EI-XPCi provides differential phase and dark-field signals, sensitive to inhomogeneities and interfaces at scales above and below the system spatial resolution, respectively. The correlation with the porosity content from matrix digestion obtained from the dark-field signal was comparable to that from ultrasonic attenuation. The novel analysis of the standard deviation of differential phase (STDP), sensitive to inhomogeneities above the system resolution (approximately 12 μm), resulted in a very high correlation (R2 = 0.995) with the matrix digestion porosity content, outperforming ultrasonic attenuation measurements.

Low energy eta-baryon interaction

The η-baryon interactions at low energies are studied using a model based on effective chiral Lagrangians, which consider baryons with spin 1/2 and spin 3/2 in the intermediate states. The interacting baryons considered in this work are B=N,Λ,Σ,Ξ. We calculate the expected total and differential cross sections, phase shifts, and polarizations in the center-of-mass frame of reference for each reaction.

Potential of Snowfall Nowcasting Using Polarimetric Radar Data and Its Link to Ice Microphysics: Study of Two Snowstorms in East China

AbstractThe microphysical characteristics, including the ice types and growth mechanisms, in two snowstorms over East China in 2016 (E16) and 2018 (E18) were explored using joint observations of a polarimetric radar and a disdrometer. In both events, the dendritic‐growth‐layer (DGL) signature (enhancements in differential reflectivity ZDR and specific differential phase KDP) was observed, indicative of the existence of horizontally‐oriented dendrites and plate‐like crystals. The KDP in the DGL, related to the total mass of ice particles, was used for snowfall nowcasting. According to the lagged correlation analysis, the reflectivity factor (ZH) near the ground, a proxy for snowfall intensity, could be well predicted by the KDP in the DGL with a 40‐min lead time and a correlation coefficient over 0.7 in E16. In contrast, E18 had a worse nowcasting performance, with the maximum correlation coefficient being ∼0.53, which could be attributed to its more complex ice microphysical structures and processes. The snow in E16 mainly grew from the deposition in the DGL (mainly dendrites and plates) and aggregation below. In comparison, the snowstorm was deeper in E18, and the less oblate crystals (with larger aspect ratios) from above the DGL could grow and mix with the dendrites and plates in the DGL, weakening the correlation between the KDP and ice mass. Below the DGL, snow growth in E18 was contributed by aggregation and more active riming according to both radar and disdrometer observations, which further lowered the nowcasting performance of snowfall by the KDP in the DGL.

Low‐profile multi‐polarization and pattern reconfigurable antenna based on metasurface

AbstractIn this letter, a low‐profile metasurface (MS) antenna with multi‐polarization and pattern reconfigurability is presented. The antenna mainly consists of two parts, including a loop antenna fed by balun, and a MS antenna excited by the coupled aperture. When switching the PIN diode and rotating the MS, the multi‐polarization and pattern reconfigurable ability of the antenna is obtained. While the loop antenna is excited, a horizontally linear polarized (HLP) wave and omnidirectional pattern are obtained. Besides, when the MS is operated, due to the differential phase between the orthogonal surface impedance components, the antenna can be switched between vertical linear polarization (VLP), left‐hand circular polarization (LHCP), and right‐hand circular polarization (RHCP). Furthermore, the antenna could achieve a directional pattern. As the simulated and measured results shown, the proposed antenna has an overlapped impedance bandwidth (IMBW) of 24.7% for all polarization modes and a 3‐dB axial ratio (AR) bandwidth of 11.8% for L/RHCP modes. Moreover, the antenna owns a low profile of 0.06 λ (under the operating centre frequency).

16-Hydroxy-ent-halima-5(10),13-dien-15,16-olide from Polyalthia longifolia targets adipogenesis by inhibiting mitotic clonal expansion and ameliorates dyslipidemia

Obesity-related metabolic disorders are increasing at an alarming rate worldwide. The FDA has approved many molecules for weight loss therapy; most of them act on the gut level by inhibiting lipid uptake or on the central nervous system by controlling appetite. Limitations and drawbacks have propelled the search for new pharmacophores exhibiting favourable metabolic alteration at adipocytes, and natural products have always been there to prove their worth. In our efforts, we have identified 16-hydroxy-ent-halima-5(10),13-dien-15,16-olide (PLH), a halimane diterpene isolated from Polyalthia longifolia, demonstrating anti-adipogenic and anti-dyslipidemic activity. It inhibited adipogenesis in 3T3-L1 preadipocyte and C3H10T1/2 mesenchymal stem cell lines. Furthermore, it decreased set of adipogenic markers at transcript and protein levels. Cell cycle studies indicated that PLH halts the mitotic clonal expansion. Mechanistic studies shows that PLH activate Wnt/β-catenin signaling pathway to inhibit the adipogenesis. The study suggested that PLH inhibited adipogenesis during the early phase of differentiation by targeting mitotic clonal expansion and arresting the cell cycle in the G1 phase of the cell cycle. It improved the dyslipidemic condition in HFD-fed hamsters by decreasing the body weight, fat mass, eWAT weight and improving the serum lipid profile. Overall, PLH has been found as a potential drug candidate and a pharmacophore for combating metabolic disorders including obesity and dyslipidemia.

Dynamic gene regulatory networks improving spike fertility through regulation of floret primordia fate in wheat.

The developmental process of spike is critical for spike fertility through affecting floret primordia fate in wheat; however, the genetic regulation of this dynamic and complex developmental process remains unclear. Here, we conducted a high temporal-resolution analysis of spike transcriptomes and monitored the number and morphology of floret primordia within spike. The development of all floret primordia in a spike was clearly separated into three distinct phases: differentiation, pre-dimorphism and dimorphism. Notably, we identified that floret primordia with meiosis ability at the pre-dimorphism phase usually develop into fertile floret primordia in the next dimorphism phase. Compared to control, increasing plant space treatment achieved the maximum increasement range (i.e., 50%) in number of fertile florets by accelerating spike development. The process of spike fertility improvement was directed by a continuous and dynamic regulatory network involved in transcription factor and genes interaction. This was based on the coordination of genes related to heat shock protein and jasmonic acid biosynthesis during differentiation phase, and genes related to lignin, anthocyanin and chlorophyll biosynthesis during dimorphism phase. The multi-dimensional association with high temporal-resolution approach reported here allows rapid identification of genetic resource for future breeding studies to realise the maximum spike fertility potential in more cereal crops.

Analysis of single photon detectors in differential phase shift quantum key distribution

Analysis of single photon detectors in differential phase shift quantum key distribution

3D Sectioning of Rough Interfaces Using Mixed-State Multislice Ptychography, Annular Dark Field, and Integrated Differential Phase Contrast Imaging.

3D Sectioning of Rough Interfaces Using Mixed-State Multislice Ptychography, Annular Dark Field, and Integrated Differential Phase Contrast Imaging.

Structural Complexity and Loss of Long-range Order in θ-Al2O3 as Revealed by HAADF and Differential Phase Contrast Imaging.

Structural Complexity and Loss of Long-range Order in θ-Al2O3 as Revealed by HAADF and Differential Phase Contrast Imaging.

STEM Tomography of Biological Samples Using Integrated Differential Phase Contrast Imaging Method.

STEM Tomography of Biological Samples Using Integrated Differential Phase Contrast Imaging Method.

Establishment and characterization of an SV40 immortalized chicken intestinal epithelial cell line

Primary chicken intestinal epithelial cells or 3D enteroids are a powerful tool to study the different biological mechanisms that occur in the chicken intestine. Unfortunately, they are not ideal for large-scale screening or long-term studies due to their short lifespan. Moreover, they require expensive culture media, coatings, or the usage of live embryos for each isolation. The aim of this study was to establish and characterize an immortalized chicken intestinal epithelial cell line to help the study of host-pathogen interactions in poultry. This cell line was established by transducing into primary chicken enterocytes the SV40 large-T antigen through a lentiviral vector. The transduced cells grew without changes up to 40 passages maintaining, after a differentiation phase of 48 h with epidermal growth factor, the biological properties of mature enterocytes such as alkaline phosphatase activity and tight junction formation. Immortalized enterocytes were able to generate a cytokine response during an inflammatory challenge, and showed to be susceptible to Eimeria tenella sporozoites invasion and generate a proper immune response to parasitic and lipopolysaccharide (Escherichia coli) stimulation. This immortalized cell line could be a cost-effective and easy-to-maintain model for all the public health, food safety, or research and pharmaceutical laboratories that study host-pathogen interactions, foodborne pathogens, and food or feed science in vitro.

Periodic-Filtering Method for Low-SNR Vibration Radar Signal

Radar is a non-contact, high-precision vibration measurement device and an important tool for bridge vibration monitoring. Vibration information needs to be extracted from the radar phase, but the radar phase information is sensitive to noise. Under low signal-to-noise ratio (SNR) data acquisition conditions, such as low radar transmission power or a long observation distance, differential phase jump errors occur and clutter estimation becomes difficult, which leads to inaccurate inversion of vibration deformation. Traditional low-pass filtering methods can filter out noise to improve SNR, but they require oversampling. The sampling rate needs to be several times higher than the Doppler bandwidth, which is several times higher than the vibration frequency. This puts high data acquisition requirements on radar systems and causes large data volumes. Therefore, this paper proposes a novel vibration signal filtering method called the periodic filtering method. The method uses the periodicity feature of vibration signals for filtering without oversampling. This paper derives the time-domain and frequency-domain expressions for the periodic filter and presents a deformation inversion process based on them. The process involves extracting the vibration frequency in the Doppler domain, suppressing noise through periodic filtering, estimating clutter using circle fitting on the data complex plane, and inverting final deformation with differential phase. The method is verified through simulation experiments, calibration experiments, and bridge vibration experiments. The results show that the new periodic filtering method can improve the SNR by five times, resolve differential phase jumps, and accurately estimate clutter, thus getting submillimeter-level vibration deformation at low SNR.

DNA-PKcs regulates myogenesis in an Akt-dependent manner independent of induced DNA damage.

Skeletal muscle regeneration relies on muscle stem (satellite) cells. We previously demonstrated that satellite cells efficiently and accurately repair radiation-induced DNA double-strand breaks (DSBs) via the DNA-dependent kinase DNA-PKcs. We show here that DNA-PKcs affects myogenesis independently of its role in DSB repair. Consequently, this process does not require the accumulation of DSBs and it is also independent of caspase-induced DNA damage. We report that in myogenic cells DNA-PKcs is essential for the expression of the differentiation factor Myogenin in an Akt2-dependent manner. DNA-PKcs interacts with the p300-containing complex that activates Myogenin transcription. We show also that SCID mice that are deficient in DNA-PKcs, and are used for transplantation and muscle regeneration studies, display altered myofiber composition and delayed myogenesis upon injury. These defects are exacerbated after repeated injury/regeneration events resulting in reduced muscle size. We thus identify a novel, caspase-independent, regulation of myogenic differentiation, and define a differentiation phase that does not involve the DNA damage/repair process.

Effects of an aged tissue niche on the immune potency of dendritic cells using simulated microgravity

Microgravity accelerates the aging of various physiological systems, and it is well acknowledged that aged individuals and astronauts both have increased susceptibility to infections and poor response to vaccination. Immunologically, dendritic cells (DCs) are the key players in linking innate and adaptive immune responses. Their distinct and optimized differentiation and maturation phases play a critical role in presenting antigens and mounting effective lymphocyte responses for long-term immunity. Despite their importance, no studies to date have effectively investigated the effects of microgravity on DCs in their native microenvironment, which is primarily located within tissues. Here, we address a significantly outstanding research gap by examining the effects of simulated microgravity via a random positioning machine on both immature and mature DCs cultured in biomimetic collagen hydrogels, a surrogate for tissue matrices. Furthermore, we explored the effects of loose and dense tissues via differences in collagen concentration. Under these various environmental conditions, the DC phenotype was characterized using surface markers, cytokines, function, and transcriptomic profiles. Our data indicate that aged or loose tissue and exposure to RPM-induced simulated microgravity both independently alter the immunogenicity of immature and mature DCs. Interestingly, cells cultured in denser matrices experience fewer effects of simulated microgravity at the transcriptome level. Our findings are a step forward to better facilitate healthier future space travel and enhance our understanding of the aging immune system on Earth.

Image Quality Improvement in Sparse-View X-Ray Phase-Contrast Trimodal CBCT With Multifrequency Fringe Modulation and Iterative Methods

X-ray grating interferometer can simultaneously retrieve attenuation, refraction and scattering signals of the imaged sample, which shows its great potential in biomedical imaging. However, fast scan of gratings and high centrifugal forces during rotating in X-ray grating-based cone-beam computed tomography (CBCT) system may lead to phase-stepping errors and grating position fluctuations, which cause reconstruction failure with phase-stepping (PS) method. Whats more, the reconstructed slices usually suffer from severe artifacts under low dose conditions. Herein, we propose a multi-frequency model to simulate the mechanical instability of the system and put forward novel iterative image reconstruction methods named MFM-TLI and MLEM-FISTA-TV to improve image quality in sparse-view trimodal CBCT. Results reveal that the model and MFM-TLI is effective to retrieve high quality absorption, differential phase contrast (DPC) and dark-field (DF) signals under mechanical instability, significantly outperforming the PS method. Image quality reconstructed by MLEM-FISTA-TV is improved compared to other iterative and analytical algorithms with sparse-view data. To the best of our knowledge, this is the first time multi-frequency method is applied in X-ray grating interferometer and iterative MLEM-TV algorithm is evaluated on experimental sparse-view dark-field CBCT data. This work might provide support for future trimodal CBCT reconstruction.

Investigating the Relationship between Polarimetric Radar Signatures of Hydrometeor Size Sorting and Tornadic Potential in Simulated Supercells

Abstract The national upgrade of the operational weather radar network to include polarimetric capabilities has led to numerous studies focusing on polarimetric radar signatures commonly observed in supercells. One such signature is the horizontal separation of regions of enhanced differential reflectivity (ZDR) and specific differential phase (KDP) values due to hydrometeor size sorting. Recent observational studies have shown that the orientation of this separation tends to be more perpendicular to storm motion in supercells that produce tornadoes. Although this finding has potential operational utility, the physical relationship between this observed radar signature and tornadic potential is not known. This study uses an ensemble of supercell simulations initialized with tornadic and nontornadic environments to investigate this connection. The tendency for tornadic supercells to have a more perpendicular separation orientation was reproduced, although to a lesser degree. This difference in orientation angles was caused by stronger rearward storm-relative flow in the nontornadic supercells, leading to a rearward shift of precipitation and, therefore, the enhanced KDP region within the supercell. Further, this resulted in an unfavorable rearward shift of the negative buoyancy region, which led to an order of magnitude less baroclinic generation of circulation in the nontornadic simulations compared to tornadic simulations.

Ultra-wideband chaotic optical communication based on electro-optic differential feedback loop

A differential feedback electro-optical phase chaotic system is proposed to generate ultra-wideband optical chaos and realize high-speed long-distance chaotic communication. The nonlinear dynamics of this differential feedback loop are studied in detail. The numerical results show, firstly, in terms of chaos complexity, the highest permutation entropy of 0.993 and the largest spectral entropy of 0.945 are achieved. Regarding the key hiding, the time delay signature of phase chaos on both the autocorrelation function and delayed mutual information can be completely suppressed, so security can be guaranteed. Secondly, the maximum bandwidth of the radio spectrum is 46.75 GHz in the range of 50 GHz, and the minimum flatness is 1.62 dB/GHz. Finally, the reception of format-transparent messages can be realized by combining co-drive synchronization and coherent demodulation. The 50 GBaud QPSK signal can transmit 2400 km and the 25 GBaud 16 QAM signal can transmit 1500 km at an OSNR of 25 dB. This system realizes ultra-wideband high-complexity chaos and chaotic communication, which can greatly improve the security, transmission distance, and transmission rate of chaotic optical communication.