768 research outputs found

    Hubbard subbands and superconductivity in the infinite-layer nickelate

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    An effective two-dimensional two-band model for infinite-layer nickelates consists of bands obtained from dx2y2d_{x^2-y^2} and ss--like orbitals. We investigate whether it could be mapped onto a single-band Hubbard model and the filling of Hubbard bands. We find that both one-band physics and a Kondo-lattice regime emerge from the same two-orbital model, depending on the strength of electronic correlations and the filling of the itinerant ss-band. Next we investigate one-particle excitations by changing the screening. First, for weak screening the strong correlations push electrons out of the ss-band so that the undoped nickelate is similar to a cuprate. Second, for strong screening the ss and dx2y2d_{x^2-y^2} bands are both partly filled and weakly couple. Particularly in this latter regime mapping to a one-band model gives significant spectral weight transfer between the Hubbard subbands. Finally we point out that the superconducting phases may have either dd-wave or ss-wave symmetry.Comment: 6 pages, 5 figures, conference. arXiv admin note: substantial text overlap with arXiv:2208.0328

    Effects of hepatocyte nuclear factor-1A and -4A on pancreatic stone protein/regenerating protein and C-reactive protein gene expression: implications for maturity-onset diabetes of the young

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    BACKGROUND: There is a significant clinical overlap between patients with hepatocyte nuclear factor (HNF)-1A and HNF4A maturity-onset diabetes of the young (MODY), two forms of monogenic diabetes. HNF1A and HNF4A are transcription factors that control common and partly overlapping sets of target genes. We have previously shown that elevated serum pancreatic stone protein / regenerating protein A (PSP/reg1A) levels can be detected in subjects with HNF1A-MODY. In this study, we investigated whether PSP/reg is differentially regulated by HNF1A and HNF4A. METHODS: Quantitative real-time PCR (qPCR) and Western blotting were used to validate gene and protein expression in cellular models of HNF1A- and HNF4A-MODY. Serum PSP/reg1A levels and high-sensitivity C-reactive protein (hsCRP) were measured by ELISA in 31 HNF1A- and 9 HNF4A-MODY subjects. The two groups were matched for age, body mass index, diabetes duration, blood pressure, lipid profile and aspirin and statin use. RESULTS: Inducible repression of HNF1A and HNF4A function in INS-1 cells suggested that PSP/reg induction required HNF4A, but not HNF1A. In contrast, crp gene expression was significantly reduced by repression of HNF1A, but not HNF4A function. PSP/reg levels were significantly lower in HNF4A subjects when compared to HNF1A subjects [9.25 (7.85-12.85) ng/ml vs. 12.5 (10.61-17.87) ng/ml, U-test P = 0.025]. hsCRP levels were significantly lower in HNF1A-MODY [0.22 (0.17-0.35) mg/L] compared to HNF4A-MODY group [0.81 (0.38-1.41) mg/L, U-test P = 0.002], Parallel measurements of serum PSP/reg1A and hsCRP levels were able to discriminate HNF1A- and HNF4A-MODY subjects. CONCLUSION: Our study demonstrates that two distinct target genes, PSP/reg and crp, are differentially regulated by HNF1A and HNF4A, and provides clinical proof-of-concept that serum PSP/reg1A and hsCRP levels may distinguish HNF1A-MODY from HNF4A-MODY subjects

    MicroRNA-224 is Readily Detectable in Urine of Individuals with Diabetes Mellitus and is a Potential Indicator of Beta-Cell Demise.

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    MicroRNA (miRNA) are a class of non-coding, 19-25 nucleotide RNA critical for network-level regulation of gene expression. miRNA serve as paracrine signaling molecules. Using an unbiased array approach, we previously identified elevated levels of miR-224 and miR-103 to be associated with a monogenic form of diabetes; HNF1A-MODY. miR-224 is a novel miRNA in the field of diabetes. We sought to explore the role of miR-224 as a potential biomarker in diabetes, and whether such diabetes-associated-miRNA can also be detected in the urine of patients. Absolute levels of miR-224 and miR-103 were determined in the urine of n = 144 individuals including carriers of a HNF1A mutation, participants with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM) and normal controls. Expression levels were correlated with clinical and biochemical parameters. miR-224 was significantly elevated in the urine of carriers of a HNF1A mutation and participants with T1DM. miR-103 was highly expressed in urine across all diabetes cohorts when compared to controls. For both miR-224 and-103, we found a significant correlation between serum and urine levels (p \u3c 0.01). We demonstrate that miRNA can be readily detected in the urine independent of clinical indices of renal dysfunction. We surmise that the differential expression levels of miR-224 in both HNF1A-MODY mutation carriers and T1DM may be an attempt to compensate for beta-cell demise

    Quantum critical behavior in disordered itinerant ferromagnets: Logarithmic corrections to scaling

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    The quantum critical behavior of disordered itinerant ferromagnets is determined exactly by solving a recently developed effective field theory. It is shown that there are logarithmic corrections to a previous calculation of the critical behavior, and that the exact critical behavior coincides with that found earlier for a phase transition of undetermined nature in disordered interacting electron systems. This confirms a previous suggestion that the unspecified transition should be identified with the ferromagnetic transition. The behavior of the conductivity, the tunneling density of states, and the phase and quasiparticle relaxation rates across the ferromagnetic transition is also calculated.Comment: 15pp., REVTeX, 8 eps figs, final version as publishe

    The Patient Perspectives on Future Therapeutic Options in NASH and Patient Needs

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    Background: Non-alcoholic steatohepatitis (NASH) is a chronic liver disease with severe complications and without approved therapies. Currently, there is limited data on the overall burden of the disease for patients or on patient needs and preferences. This study investigates patient preferences in relation to potential future therapies for NASH. In addition, the factors that are relevant to patients and their importance in relation to future treatment options are explored.Method: Telephone in-depth interviews (TDIs) preceded an online 30-min quantitative survey. The online survey included (1) multiple choice questions (MCQs) on NASH diagnosis and disease background. (2) An exercise to determine patients' satisfaction levels with information provided at diagnosis, and to explore symptomatology in detail. (3) Exercises to evaluate potential new products and product attributes, including a “drag and drop” ranking exercise, and an adaptive choice-based conjoint exercise (ACBC). (4) The EQ-5D-5L questionnaire and the Visual Analog Scale (VAS), which measures patients' health status. (5) Collection of socio-demographic data, and (6) Questions to measure patient satisfaction with the survey.Results: There were 166 patients included in this study from Canada [n = 36], Germany [n = 50], the UK [n = 30], and USA [n = 50]. Fifty seven percent of patients [n = 94] had had a liver biopsy for confirmation of NASH. Patients were often unable to link their symptoms to NASH or other conditions. ACBC results showed that efficacy, defined as “impact on liver status” was the single most important attribute of a potential future NASH therapy. Other attributes considered to have secondary importance included impact on weight, symptom control and the presence of side effects. The EQ-5D utility score was 0.81 and VAS = 67.2.Conclusion: “Impact on liver status” is the primary outcome sought. Patients demonstrate a general lack of understanding of their disease and appeared to be unfamiliar with longer-term consequences of NASH. It is necessary to improve patient understanding of NASH and its progressive nature, and there is a need for improving confirmatory diagnosis and monitoring

    Pro-inflammatory activation following demyelination is required for myelin clearance and oligodendrogenesis

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    Remyelination requires innate immune system function, but how exactly microglia and macrophages clear myelin debris after injury and tailor a specific regenerative response is unclear. Here, we asked whether pro-inflammatory microglial/macrophage activation is required for this process. We established a novel toxin-based spinal cord model of de- and remyelination in zebrafish and showed that pro-inflammatory NF-κB-dependent activation in phagocytes occurs rapidly after myelin injury. We found that the pro-inflammatory response depends on myeloid differentiation primary response 88 (MyD88). MyD88-deficient mice and zebrafish were not only impaired in the degradation of myelin debris, but also in initiating the generation of new oligodendrocytes for myelin repair. We identified reduced generation of TNF-α in lesions of MyD88-deficient animals, a pro-inflammatory molecule that was able to induce the generation of new premyelinating oligodendrocytes. Our study shows that pro-inflammatory phagocytic signaling is required for myelin debris degradation, for inflammation resolution, and for initiating the generation of new oligodendrocytes

    Cohesin depleted cells pass through mitosis and reconstitute a functional nuclear architecture

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    The human genome forms thousands of “contact domains”, which are intervals of enhanced contact frequency. Some, called “loop domains” are thought to form by cohesin-mediated loop extrusion. Others, called “compartmental domains”, form due to the segregation of active and inactive chromatin into A and B compartments. Recently, Hi-C studies revealed that the depletion of cohesin leads to the disappearance of all loop domains within a few hours, but strengthens compartment structure. Here, we combine live cell microscopy, super-resolution microscopy, Hi-C, and studies of replication timing to examine the longer-term consequences of cohesin degradation in HCT-116 human colorectal carcinoma cells, tracking cells for up to 30 hours. Surprisingly, cohesin depleted cells proceed through an aberrant mitosis, yielding a single postmitotic cell with a multilobulated nucleus. Hi-C reveals the continued disappearance of loop domains, whereas A and B compartments are maintained. In line with Hi-C, microscopic observations demonstrate the reconstitution of chromosome territories and chromatin domains. An interchromatin channel system (IC) expands between chromatin domain clusters and carries splicing speckles. The IC is lined by active chromatin enriched for RNA Pol II and depleted in H3K27me3. Moreover, the cells exhibit typical early-, mid-, and late- DNA replication timing patterns. Our observations indicate that the functional nuclear compartmentalization can be maintained in cohesin depleted pre- and postmitotic cells. However, we find that replication foci – sites of active DNA synthesis – become physically larger consistent with a model where cohesin dependent loop extrusion tends to compact intervals of replicating chromatin, whereas their genomic boundaries are associated with compartmentalization, and do not change.3D FISH3D fluorescence in situ hybridization3D SIM3D structured illumination microscopyAIDauxin inducible degronANC / INCactive / inactive nuclear compartmentCTchromosome territoryCD(C)chromatin domain (cluster)CTCFCCCTC binding factorDAPI4’,6-diamidino-2-phenylindoleEdU5-Ethynyl-2’-deoxyuridineHi-Cchromosome conformation capturing combined with deep sequencingICinterchromatin compartmentMLNmultilobulated nucleusNCnucleosome clusterPBSphosphate buffered salinePBSTphosphate buffered saline with 0.02% TweenPRperichromatin regionRDreplication domainRLreplication labelingTADtopologically associating domai
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