891 research outputs found

    Self-consistent variational theory for globules

    Full text link
    A self-consistent variational theory for globules based on the uniform expansion method is presented. This method, first introduced by Edwards and Singh to estimate the size of a self-avoiding chain, is restricted to a good solvent regime, where two-body repulsion leads to chain swelling. We extend the variational method to a poor solvent regime where the balance between the two-body attractive and the three-body repulsive interactions leads to contraction of the chain to form a globule. By employing the Ginzburg criterion, we recover the correct scaling for the θ\theta-temperature. The introduction of the three-body interaction term in the variational scheme recovers the correct scaling for the two important length scales in the globule - its overall size RR, and the thermal blob size ξT\xi_{T}. Since these two length scales follow very different statistics - Gaussian on length scales ξT\xi_{T}, and space filling on length scale RR - our approach extends the validity of the uniform expansion method to non-uniform contraction rendering it applicable to polymeric systems with attractive interactions. We present one such application by studying the Rayleigh instability of polyelectrolyte globules in poor solvents. At a critical fraction of charged monomers, fcf_c, along the chain backbone, we observe a clear indication of a first-order transition from a globular state at small ff, to a stretched state at large ff; in the intermediate regime the bistable equilibrium between these two states shows the existence of a pearl-necklace structure.Comment: 7 pages, 1 figur

    PENGARUH MEDIA VIDEO ANIMASI TERHADAP HASIL BELAJAR IPAS MATERI SIKLUS AIR PADA SISWA KELAS V SD GMIT KUANINO 3 KOTA KUPANG

    Get PDF
    This research aims to find out whether animated video media has a significant influence on science learning outcomes regarding the water cycle in class V students at SD GMIT Kuanino 3, Kupang City. The type of research used is Quasi Experimental Design. The sampling technique used was purposive sampling technique with a sample size of 11 people. The research results prove that there is a significant influence between animated video media on student learning outcomes. This is proven by the difference in students\u27 completeness scores before being given treatment (pretest) and after being given treatment (posttest). There were 2 students who completed the pretest, while 11 students completed the posttest, so it can be said that the use of animated video media regarding the water cycle can improve student learning outcomes. The normality test of learning outcomes from the pretest-posttest obtained a significant value of 0.200 for the pretest and 0.127 for the posttest > 0.05 so that the data was normally distributed, the homogeneity test results showed (sig) Levene\u27s of 0.438 > 0.05 so the data obtained was homogeneous. Apart from that, testing the hypothesis with the t test using SPSS version 25 obtained a significance value (2-tailed) 0.000 < 0.05. Thus, animated video media has a significant influence on student learning outcomes

    SARS CoV-2 aggravates cellular metabolism mediated complications in COVID-19 infection.

    Full text link
    Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the primary causative organism in corona virus disease-19 (COVID-19) infections, is a novel member of the human coronavirus family which was first identified in Wuhan, China, towards the end of 2019. This letter reveals new vital missing links in our current understanding of the mechanisms that lead to cell death triggered by ferroptotic stress in COVID-19 infection. It further reveal the importance of homocysteine mediated trans-sulfuration pathway in COVID-19 infection. Hence, Vitamin B6, folic acid, and Vitamin B12 should be incorporated in the treatment regimen for SARS CoV-2 infections to suppress complications, as the virus mediates altered host cell metabolism

    Role of microRNAs (miRNAs) in the pathophysiology of Diabetes mellitus

    Full text link
    © 2017 EDIZIONI MINERVA MEDICA. Diabetes mellitus is becoming the critical problem among the entire world and it is difficult to understand the molecular mechanism representing the concept of diabetic pathology. Recently the knowledge of the involvement of genetics in type 2 diabetes mellitus (T2DM) susceptibility has sketched a great concentration towards the transcriptional activity of β cells within the pancreas. This disease becomes the leading cause of death, so it is necessary to study the molecular pathogenesis, phenotypes, and characteristics to design the therapeutic parameters. Here in this review role of miRNA is being illustrated as it plays a crucial role in the pathogenesis, progression, and fate of beta cells of pancreas regulating the insulin secretion. Here in this review, we try to include the effects and pathophysiology of various miRNA in diabetes mellitus and on the various sites of the human body

    The visualisation of vitreous using surface modified poly(lactic-co-glycolic acid) microparticles

    Get PDF
    This paper is freely available online under the BMJ Journals unlocked scheme, see http:// bjo.bmj.com/site/about/unlocked.xhtmAims To demonstrate the potential use of in vitro poly (lactic-co-glycolic acid) (PLGA) microparticles in comparison with triamcinolone suspension to aid visualisation of vitreous during anterior and posterior vitrectomy. Methods PLGA microparticles (diameter 10-60 mu m) were fabricated using single and/or double emulsion technique(s) and used untreated or following the surface adsorption of a protein (transglutaminase). Particle size, shape, morphology and surface topography were assessed using scanning electron microscopy (SEM) and compared with a standard triamcinolone suspension. The efficacy of these microparticles to enhance visualisation of vitreous against the triamcinolone suspension was assessed using an in vitro set-up exploiting porcine vitreous. Results Unmodified PLGA microparticles failed to adequately adhere to porcine vitreous and were readily washed out by irrigation. In contrast, modified transglutaminase-coated PLGA microparticles demonstrated a significant improvement in adhesiveness and were comparable to a triamcinolone suspension in their ability to enhance the visualisation of vitreous. This adhesive behaviour also demonstrated selectivity by not binding to the corneal endothelium. Conclusion The use of transglutaminase-modified biodegradable PLGA microparticles represents a novel method of visualising vitreous and aiding vitrectomy. This method may provide a distinct alternative for the visualisation of vitreous whilst eliminating the pharmacological effects of triamcinolone acetonide suspension.Peer reviewedFinal Published versio

    Loss of Hyaluronan and Proteoglycan Link Protein-1 Induces Tumorigenesis in Colorectal Cancer

    Full text link
    Colorectal cancer (CRC) is the third most common diagnosed cancer worldwide, but there are no effective cures for it. Hyaluronan and proteoglycan link protein-1 (HAPLN1) is a component of the extracellular matrix (ECM) proteins and involved in the tumor environment in the colon. Transforming growth factor (TGF)-β is a key cytokine that regulates the deposition of ECM proteins in CRC. However, the role of HAPLN1 in TGF-β contributions to CRC remains unknown. We found that the mRNA expression of HAPLN1 was decreased in tumors from CRC patients compared with healthy controls and normal tissue adjacent to the tumor using two existing microarray datasets. This was validated at the protein level by tissue array from CRC patients (n = 59). HAPLN1 protein levels were also reduced in human CRC epithelial cells after 24 h of TGF-β stimulation, and its protein expression correlated with type I collagen alpha-1 (COL1A1) in CRC. Transfection of HAPLN1 overexpression plasmids into these cells increased protein levels but reduced COL1A1 protein, tumor growth, and cancer cell migration. TGF-β stimulation increased Smad2/3, p-Smad2/3, Smad4, and E-adhesion proteins; however, HAPLN1 overexpression restored these proteins to baseline levels in CRC epithelial cells after TGF-β stimulation. These findings suggest that HAPLN1 regulates the TGF-β signaling pathway to control collagen deposition via the TGF-β signaling pathway and mediates E-adhesion to control tumor growth. Thus, treatments that increase HAPLN1 levels may be a novel therapeutic option for CRC.</jats:p
    corecore