Absence Of Gr Research Articles

Photoluminescence patterns via single-layer exfoliation in Gr/MoS2 heterostructure using contact-mode atomic force microscopy

The stacking of two-dimensional (2D) materials presents numerous opportunities for various nanodevice applications. Achieving atomic-thick precision in microscopic patterning is crucial to manipulating the functionalities and interfacial interactions of the 2D heterostructures. In this study, a silicon atomic force microscopy (AFM) tip was utilized to rub the surface of graphene (Gr)/MoS2 heterostructure and manipulate its physical properties. The contact force between the AFM tip and Gr/MoS2 surface was adjusted between 110 and 660 nN. Before rubbing, the photoluminescence (PL) intensity of MoS2 was quenched due to the presence of Gr. After rubbing, the optical image and Raman spectroscopy acquired from the Gr/MoS2 heterostructure indicated that Gr started to be exfoliated by a contact force exceeding 220 nN. The absence of Gr due to exfoliation led to the restoration of MoS2′s pristine PL intensity. For demonstration, the AFM tip was used to exfoliate a designed micro-area covered with Gr using a 660 nN force, forming a patterned PL of MoS2. This technique enabled the creation of different structures to develop unique multilayer 2D material devices.

FRI164 The Glucocorticoid Receptor is Required for Efficient Aldosterone-induced Transcription by the Mineralocorticoid Receptor

Abstract Disclosure: T.A. Johnson: None. G. Fettweis: None. K. Wagh: None. B. Almeida-Prieto: None. G.L. Hager: None. D. Alvarez de la Rosa: None. The glucocorticoid and mineralocorticoid receptors (GR and MR, respectively) have distinct, yet overlapping physiological and pathophysiological functions. There is evidence in the literature that the two receptors interact both functionally and physically, but the global role of this interdependence is poorly understood (1,2). Here, we analyze the impact of GR co-expression on MR genome-wide chromatin binding and transcriptional responses to aldosterone and glucocorticoids. Our data show that GR co-expression alters MR genome-wide binding in locus- and ligand-specific ways. MR binding to consensus hormone response elements is affected by GR. Additionally, gene responses by MR in the absence of GR are weak and show poor correlation with chromatin binding. In contrast, co-expression of GR greatly potentiates genome-wide MR-mediated transcription, particularly in response to aldosterone. These aldosterone-mediated transcriptional responses do not occur with GR alone. Finally, single molecule tracking of MR in live cells indicates that the presence of GR contributes to productive chromatin binding events. Together, our data indicate that co-expression of GR enables optimal aldosterone-mediated MR transcriptional activity, even in the absence of glucocorticoids. REFERENCES: (1) Mayumi Nishi et al., J Neuroscience. 2004 May 26; 24(21):4918 - 4927. (2) Liu et al., PNAS. Dec 1995; 92: 12480-12484. Presentation Date: Friday, June 16, 2023

Effects of an epitaxial graphene layer for the growth of nickel silicides on a Ni(111) substrate

In this paper, we report on an in-depth study on the growth of nickel silicides, either on a clean Ni(111) substrate or in the presence of a previously-grown epitaxial single graphene (Gr) layer, by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). We demonstrate that two different nickel silicides, namely Ni3Si and Ni2Si, progressively form as the annealing temperature is increased from 450 °C to 600 °C. The presence of the Gr layer does not change the nature of the two silicide phases but rather affects the morphology of the silicide overlayer. Indeed, in the presence of Gr, the deposited silicon atoms intercalate by passing through the Gr defects or domain boundaries and accumulate on specific sample areas, resulting in the formation of multilayer silicide islands. In the absence of Gr, the deposited silicon atoms react uniformly with the nickel substrate, resulting in the formation of homogeneous large scale silicide layers.

Hepcidin Suppression By Momelotinib Is Associated with Increased Iron Availability and Erythropoiesis in Transfusion-Dependent Myelofibrosis Patients

Hepcidin Suppression By Momelotinib Is Associated with Increased Iron Availability and Erythropoiesis in Transfusion-Dependent Myelofibrosis Patients

Nanofriction of Graphene/Ionic Liquid-Infused Block Copolymer Homoporous Membranes.

We have infused graphene/ionic liquid into block copolymer homoporous membranes (HOMEs), which have highly ordered uniform cylindrical nanopores, to form compact, dense, and continuous graphene/ionic liquid (Gr/IL) lubricating layers at interfaces, enabling a reduction in the friction coefficient. Raman and XPS analyses, confirmed the parallel alignment of the cation of ILs on graphene by the π-π stacking interaction of the imidazolium ring with the graphene layer. This alignment loosens the lattice spacing of Gr in Gr/ILs, leading to a larger lattice spacing of 0.36 nm in Gr of Gr/ILs hybrids than the pristine Gr (0.33 nm). The loose graphene layers, which are caused by the coexistence of graphene and ILs, would make the sliding easier, and favor the lubrication. An increase in the friction coefficient was observed on ILs-infused block copolymer HOMEs, as compared to Gr/ILs-infused ones, due to the absence of Gr and the unstably formed ILs film. Gr/ILs-infused block copolymer HOMEs also exhibit much smaller residual indentation depth and peak indentation depth in comparison with ILs-infused ones. This indicates that the existence of stably supported Gr/ILs hybrid liquid films aids the reduction of the friction coefficient by preventing the thinning of the lubricant layer and exposure of the underlying block copolymer HOMEs.

Seed Yield and Yield Stability of Chickpea in Response to Cropping Systems and Soil Fertility in Northern Latitudes

Improved cultural practices are required to enhance the adaptability of chickpea (Cicer arietinum L.) in northern latitudes. Field experiments were conducted to determine the effects of cropping systems, cultivar choices, and soil fertility on the stand establishment, seed yield, and yield stability of chickpea in northern latitudes. Four cultivars were tested in no‐till barley (Hordeum vulgare L.), no‐till wheat (Triticum aestivum L.), and tilled‐fallow systems at six environments in southern Saskatchewan, 2004–2006. Crop received N fertilizer at 0, 28, 64, 84, and 112 kg N ha−1 with or without Rhizobium inoculant (GR). The no‐till barley and no‐till wheat systems did not differ from the tilled‐fallow system in days to plant emergence and stand establishment, and the two no‐till systems averaged 2100 kg ha−1of seed yield which was 83% of the yield in the tilled‐fallow system. In the absence of GR, increasing N rates increased seed yield significantly in the two no‐till systems, no yield responses in the tilled‐fallow system, and decreased plant density in all the three systems. Compared to the non‐GR control, the use of GR increased seed yield by 37% in the no‐till systems and 8% in the tilled‐fallow system. Chickpea inoculated with GR produced a similar yield as was fertilized at 112 kg N ha−1. Chickpea receiving fertilizer N plus GR produced a similar yield as the crop received GR only for all cultivars. Use of optimal cropping systems, improved cultivars with high yield stability, and application of effective N‐fixing inoculants will enhance the adaptability of chickpea in northern latitudes.

Assessment of Bleeding in Thrombocytopenic Patients (pts) with Immune Thrombocytopenic Purpura (ITP).

Introduction: Assessment of bleeding in ITP is difficult. There is no agreed upon methodology; the WHO bleeding score does not seem useful for ITP. We report an ITP bleeding score including the relationship between site-specific bleeding severity (BLS), platelet count (plt ct), and plt size.Methods: A bleeding score was created which has 11 sites, 9 by history (Hx) of the previous week: skin, oral, epistaxis, GI, GU, GYN, hemoptysis, subconjunctival (SC), and intracranial hemorrhage (ICH); and 2 by Exam (PE): skin and oral. The BLS grades (gr) pts for each site on a defined scale from no bleeding (0) to “major” bleeding (2). Plt cts and large plts (LP) were measured on the Bayer Advia 120. No pt had > 2 study visits.Results: The 65 ITP pts on 100 visits over 6 months had a median (mdn) plt ct of 41,500/uL (41.5k). The mdn age was 31.5 yrs; 20 pts were children. 56 pts had chronic ITP, 26 s/p splenectomy, with a mdn duration of ITP of 6 yrs. There were no GU, SC hemorrhage (hem), or ICH. 72% of all gr 1 hem's were skin whereas 46% of gr 2 hem's were oral. There was 1 GI hem and 3 hemoptysis visits that were gr 2. 42 women on 63 visits had 5 visits each with GYN BLS gr 1 and gr 2. X2 testing correlated plt ct and BLS for 6 sites: both oral and both skin sites, epistaxis, and GYN (p's < 0.05). Oral PE correlated best with the plt ct (fig 1). For oral PE, BLS of gr 2 did not occur at plt cts > 20k.When the BLS was scored independently by two observers (LKP & JB) on 63 of the100 visits, 92% of individual BLS grs were identical (PearsonR=0.75). Skin PE and epistaxis each had 11/63 discrepancies. In addition, 16 BLS for oral (15 for skin) were different comparing Hx and PE (fig 2).LP did not correlate well with site-specific BLS when only plt cts ≤ 30k were included, suggesting that large, young platelets may not primarily determine bleeding severity in ITP. However for Skin Hx, if the BLS was gr 0, 4/6 had LP ≥ 2 whereas only 7/28 LP were ≥ 2 when the BLS was gr 1.Conclusions: The Bleeding Score reported here was validated by: a) the relationship of bleeding severity at multiple sites to plt ct including the absence of gr 2 bleeding at plt cts >20k; and b) the high degree of interobserver reliability despite a low but irreducible error rate based on variability in pt recall. It takes ≤ 3–5 minutes to complete. The significance of LP remains unclear. Studies of the BLS in larger numbers of patients will further determine its usefulness. [Display omitted] [Display omitted]

The epithelial glucocorticoid receptor is required for the normal timing of cell proliferation during mammary lobuloalveolar development but is dispensable for milk production.

Glucocorticoids have been shown to influence mammary gland function in vivo and to stimulate milk protein gene expression in vitro. Here, we describe the generation and analysis of a mouse model to study glucocorticoid receptor (GR, NR3C1) function in mammary epithelial cells. Using the Cre-loxP system, mutant mice were obtained in which the GR gene is specifically deleted in epithelial cells during lobuloalveolar development, leading to a complete loss of epithelial GR at the onset of lactation. Mice harboring the mammary-epithelial-specific GR mutation are able to nurse their litters until weaning. During pregnancy, however, GR deficiency delays lobuloalveolar development, leading to an incomplete epithelial penetration of the mammary fat pad that persists throughout lactation. We identified a reduced cell proliferation during lobuloalveolar development as reason for this delay. This reduction is compensated for by increased epithelial proliferation after parturition in the mutant glands. During lactation, GR-deficient mammary epithelium is capable of milk production and secretion. The expression of two milk proteins, namely whey acidic protein and beta-casein, during lactation was not critically affected in the absence of GR. We conclude that GR function is not essential for alveolar differentiation and milk production, but influences cell proliferation during lobuloalveolar development.

Simultaneous Regeneration of Different Morphogenic Structures from Quince Leaves as Affected by Growth Regulator Combination and Treatment Length

Experiments were performed to evaluate the capacity of quince (Cydonia oblonga Mill.) leaves to regenerate somatic embryos and shoots and/or roots simultaneously. Leaves, treated for 2 d in liquid medium containing 2.5 mg dm-3 2,4-dichlorophenoxyacetic acid were cultured for 0, 3, 6, 9, 12, 15, 18, 21 d on a gelled medium supplemented with 1 mg dm-3 kinetin (Kin) and 0.1 mg dm-3 naphthalenacetic acid (NAA) and were transferred to a medium either without growth regulator (GR-) or containing 0.6 mg dm-3 6-benzylaminopurine (BA) + 0.2 mg dm-3 gibberellic acid (GA3) + 0.06 mg dm-3 indole-3-butyric acid (IBA) (GR+). Leaves producing somatic embryos (SEs) only, or adventitious roots (Rs) only, or SEs+Rs simultaneously, were detected on GR- culture medium; on GR+ medium, leaves producing adventitious shoots (Ss) only, SEs+Ss or SEs+Rs+Ss simultaneously, also appeared. Leaves producing both Ss+Rs were never detected. Proportions among the various types of regenerating leaves varied according to both the length of Kin+NAA treatment and the presence or absence of GR in the transfer medium. The greatest variations, both on GR- and on GR+, took place within the first 9 d of culturing on Kin+NAA. After this period, no further substantial differences in the trend of each type of regenerating leaf were observed. The length of the treatment with Kin+NAA also modified the proportions between the different types of morphogenic structures.

Lineage-specific growth factors can compensate for stem and progenitor cell deficiencies at the postprogenitor cell level: an analysis of doubly TPO- and G-CSF receptor–deficient mice

Multiple lines of evidence indicate that thrombopoietin (TPO) substantially impacts the number of hematopoietic stem cells and progenitors of all myeloid lineages. Nevertheless, tpo knock-out mice (T(-)) display thrombocytopenia only; blood erythroid and neutrophil levels are normal despite 60% to 85% reductions in stem and progenitor cells. The compensatory mechanism(s) for these deficiencies remains uncertain; lineage-specific cytokines such as erythropoietin or granulocyte colony-stimulating factor (G-CSF) have been postulated but never proven to be responsible. To directly test whether G-CSF can compensate for the myeloid progenitor cell reduction in the T(-) model of hematopoietic deficiency, T(-) and G-CSF-receptor knock-out (GR(-)) mice were crossed, and F1 animals bred to obtain doubly nullizygous mice (T(-)GR(-)). This experiment also allowed us to test the hypothesis that G-CSF contributes to the residual platelet production in T(-) mice. We found that T(-)GR(-) F2 mice displayed similar blood platelet levels as that seen in T(-) mice, indicating that G-CSF does not account for the residual megakaryopoiesis in T(-) mice. However, we also noted excessive perinatal mortality of T(-)GR(-) animals, caused by infection due to a profound and significant decrease in marrow and peripheral blood neutrophils, far greater than that seen in either T(-) or GR(-) mice. These data indicate that in the additional absence of GR, T(-) mice cannot compensate for their 62% reduction in myeloid progenitors and become profoundly neutropenic, supporting the hypothesis that G-CSF can compensate for the myeloid effects of TPO deficiency by expanding the pool of cells between the granulocyte-macrophage colony-forming unit and mature neutrophil stages of granulopoiesis.

Germination of Orobanche crenata Forsk. seeds in vitro

Summary:The effects of calcium hypochlorite [Ca(OCl)2] and gibberellic acid (GA), both in combination and separately, were studied on the germination of Orobanche crenata seeds. Hypochlorite was applied either before or after the conditioning phase for periods up to 150 min. The seeds were exposed to GA during the conditioning phase. After conditioning the seeds were exposed to either the synthetic germination stimulant GR 7, flax root exudate (FRE) or distilled water.GR 7 exploited the germination potential of O. crenata better than FRE and this in turn better than water. In the presence of GR 7 or FRE the number of germinating seeds generally increased when the seeds were briefly (5–20 min) exposed to hypochlorite. In the absence of GR 7 and FRE, hypochlorite only increased germination if the seeds were treated during medium‐long periods (20–60 min) after conditioning. If GR 7 or FRE were not applied the germination percentage was usually significantly higher when conditioning was done in the presence of GA.