The Puzzling Bulge to Disk Nova Ratio in the Andromeda Galaxy (M31)

Novae in M31 are often associated with the bulge component of the light from this galaxy, i.e., more novae are assumed to be produced in the bulge of M31. But examining this from a population synthesis approach, one expects that evolved binaries in the disk should produce more novae. We strive to understand this bulge to disk nova ratio puzzle in M31 by exploring two scenarios. The nova rate normalized to the K-band luminosity for different galaxy Hubble types is approximately constant. We utilize this observed correlation to model the bulge and disk nova distribution. However, the decomposition of K light into bulge and disk does not yield a good match to the observed spatial distribution of novae in M31. Therefore, we conclude that the assumption that the nova rate follows total K light is too simple to explain the actual distribution of novae in this galaxy. Second, we examine the role of dust in the disk of M31 in extinction novae, possibly more so in the disk, which would increase the relative number of observed bulge novae compared to those in the disk. We construct a three dimensional multi-component dust model (uniform background, 10 kpc ring, 2 logarithmic spirals) and apply it to novae in the bulge and the disk of M31. With model parameters calibrated from infrared emission models, this results in hiding only ~ 1 % of the novae in the disk and 0.3-0.4 % in the bulge. We, therefore conclude that dust in M31 does not play a significant role in shrouding novae in the disk. In fact, the effect of the dust is not much higher for disk novae in comparison to bulge novae. Therefore, we conclude that the common assumption that \u27novae trace the K-band light\u27 is not supported by the detailed spatial models of novae in M31, and that extinction by dust is insufficient to resolve the puzzle of the relative scarcity of disk novae in M31

The Role of PME-1 in Cancer: Therapeutic Implication

Protein phosphatase 2A (PP2A) plays a major role in maintaining cellular signaling homeostasis in human cells by reversibly affecting the phosphorylation of a variety of proteins. Protein phosphatase methylesterase-1 (PME-1) negatively regulates PP2A activity by reversible demethylation and active site binding. Thus far, it is known that overexpression of PME-1 in human gliomas contributes to ERK pathway signaling, cell proliferation, and malignant progression. Whether PME-1-mediated PP2A inhibition promotes therapy resistance in gliomas is unknown. Specific PP2A targets regulated by PME-1 in cancers also remain elusive. Additionally, whether oncogenic function of PME-1 can be generalized to various human cancers needs to be investigated. This study demonstrated that PME-1 expression promotes kinase inhibitor resistance in glioblastoma (GBM). PME-1 silencing sensitized GBM cells to a group of clinically used indolocarbazole multikinase inhibitors (MKIs). To facilitate the quantitative evaluation of MKIs by cancer-cell specific colony formation assay, Image-J software-plugin ‘ColonyArea’ was developed. PME-1-silencing was found to reactivate specific PP2A complexes and affect PP2A-target histone deacetylase HDAC4 activity. The HDAC4 inhibition induced synthetic lethality with MKIs similar to PME-1 depletion. However, synthetic lethality by both approaches required co-expression of a pro-apoptotic protein BAD. In gliomas, PME-1 and HDAC4 expression was associated with malignant progression. Using tumor PME-1, HDAC4 and BAD expression based stratification signatures this study defined patient subgroups that are likely to respond to MKI alone or in combination with HDAC4 inhibitor therapies. In contrast to the oncogenic role of PME-1 in certain cancer types, this study established that colorectal cancer (CRC) patients with high tumor PME-1 expression display favorable prognosis. Interestingly, PME-1 regulated survival signaling did not operate in CRC cells. Summarily, this study potentiates the candidacy of PME-1 as a therapy target in gliomas, but argues against generalization of these findings to other cancers, especially CRC.PME-1:n vaikutukset syövässä ja niiden terapeuttinen potentiaali Proteiinifosfataasi 2A (PP2A)-entsyymillä on tärkeä rooli solun sisäisen signaloinnin säätelyssä sillä se defosforyloi lukuisia signalointi-proteiineja. Proteiinifosfataasi metyyliesteraasi-1 (PME-1)-entsyymi taas säätelee negatiivisesti PP2A:n aktiivisuutta demetyloimalla sitä. Ihmisen glioomassa PME-1:n korkea ilmentyminen lisää syöpää edistävän ERK-signalointireitin aktiivisuutta syöpäsoluissa, syöpäsolujen jakautumista ja edelleen syövän pahanlaatuisuutta. Toistaiseksi on vielä selvittämättä, edistääkö PME-1:n välittämä PP2A:n esto terapiaresistenssiä glioomassa. Lisäksi PME-1:n säätelemät spesifiset PP2A:n kohde-proteiinit syövässä ovat vielä tuntemattomia. Lisätutkimuksia myös kaivataan PME-1:n roolista eri syöpätyypeissä. Tämä tutkimus osoitti, että PME-1:n ilmentyminen lisää resistenssiä kinaasi-inhibiittoreille glioblastoomassa (GBM). PME-1-geenin hiljentäminen altisti GBM-solut indolokarbatsoli ryhmän multikinaasi-inhibiittoreille (MKI) jotka ovat kliinisessä kehityksessä muihin syöpätyyppeihin. Parantaaksemme MKI-yhdisteiden vaikutusten arviointia pesäkemuodostukseen syöpäsoluviljelmissä, kehitimme “ColonyArea” lisäosan Image-J-ohjelmaan. Osoitimme, että PME-1:n hiljentäminen lisää spesifisten PP2A-kompleksien aktiivisuutta ja säätelee PP2A:n kohdeproteiinia, histonideasetylaasia (HDAC4). Kuten PME-1:n hiljentäminen, myös HDAC4:n esto yhdessä MKI-yhdisteiden kanssa indusoi synteettistä letaalisuutta glioomasoluissa. Kumpikin mekanismi vaatii apoptoosia edistävän BAD-proteiinin ilmentymisen. PME-1:n ja HDAC4:n ilmentyminen korreloi gliooman etenemiseen. Kasvaimien PME-1, HDAC4 ja BAD ilmentymistasojen perusteella voitaisiinkin mahdollisesti erotella glioomapotilaat, jotka reagoivat MKI-terapiaan joko HDAC4-inhibiittoriterapian kanssa tai ilman. Päinvastoin kuin tietyissä muissa syöpätyypeissä, korkea PME-1:n ilmentyminen paransi potilaiden ennustetta paksusuolen syövässä. PME-1 ei lisännyt selviytymistä edistävien signalointireittien aktiivisuutta paksusuolen syöpäsoluissa. Yhteenvetona tämä tutkimus osoittaa PME-1:n olevan potentiaalinen lääkehoidon kohde gliooman hoidossa, mutta tämä löydös ei ole välttämättä yleistettävissä muiden syöpien, tai ei ainakaan paksusuolen syövän hoidossa.Siirretty Doriast

Cross Culturalism in Bharati Mukherjee's Jasmine

Multiculturalism is a burning issue today and the critical analysis of Bharati Mukherjee's selected novel Jasmine brings into focus the immigrant experience of the female's self of being a woman and being an immigrant woman. It also covers cross-cultural experiences such as the rootlessness, the identity issues and the assimilation of the protagonists in her novels. The present research paper analyses Bharati Mukherjee's Jasmine from a cross-cultural perspective. She is one of the renowned and established female writers of Indian diaspora in the United States. Her key objective is to explore and examine an impenetrable cross cultural awareness of those who connect with more than one culture. Her keen interest is to explore the plights and pains of South Asian immigrants in America and Canada and to bring about how immigrants face the problem of acculturation and cultural conflicts in adapted lands. Cultural alienation, displacement, survival and adjustment are the most frequent themes in her novels. Her own journey of life stretches across India, Canada and the United States. Almost her all novels reflect the themes of migration, exile, cultural alienation, assimilation and identity issues

App Review: Trello

This article focuses on using Trello, a collaborative project management tool

Identifying the 3FHL catalog: I. Results of the KOSMOS optical spectroscopy campaign

We present the results of the optical spectroscopy follow-up of a sample of 28 unclassified blazars from the Third Fermi-LAT Catalog of High-Energy Sources (3FHL). All the spectra were taken with the 4m Mayall telescope at Kitt Peak. With this follow-up program we are able to classify 27 out of 28 objects as BL Lacs, while the remaining one is a flat spectrum radio quasar. We determine a redshift (z) for three of these objects and a lower limit on z for other four sources: the farthest object for which we obtain a redshift has z>0.836. These results are part of a more extended campaign of optical spectroscopy follow-up of 3FHL blazars, aimed to obtain a complete sample of blazars at >10 GeV which will then be used to extend our knowledge on blazar emission mechanisms and on the extragalactic background light.Comment: 12 pages, 6 figures. Accepted for publication on the Astronomical Journal Supplement Series. The spectra analyzed in this work are available at the following link: https://clemson.app.box.com/s/uu1hk6g4qy0ow9j4nst4nifm3mmrs19

Investigation of azo-bond cleavage in Methyl Orange and Direct Yellow 12 using soybean peroxidase

Removal of dyes released in water by textile industries presents a major challenge for the researchers. Soybean peroxidase (SBP) has been widely explored for removal of a variety of toxic aromatics consisting of phenolic or anilino functional groups. Also, it has been known to possess the ability of azo-bond cleavage. This thesis was aimed to investigate azo-bond cleavage by SBP in the presence of hydrogen peroxide, if possible, in the absence of these functional groups. Direct Yellow 12 and azobenzene were chosen as a model compounds for this study. Experiments were conducted at a range of pHs, SBP and hydrogen peroxide to investigate the hypothesis. Enzymatic removal of p-anisidine and Methyl Orange (MO) and azo-bond cleavage of MO were also studied. Optimization of pH, hydrogen peroxide-to-substrate ratio and SBP activity were performed to achieve ≥95% removal of these substrates in 3 hours, analyzed using high-performance liquid chromatography. A time course study was conducted to calculate pseudo-first-order rate constants and half-lives for degradation of these compounds. Mass spectrometry analysis showed oligomerization of p-anisidine and for MO, evidence of azo-bond cleavage was obtained after the enzymatic treatment

Ultraluminous X-ray Sources in Andromeda Galaxy: Two Recent Discoveries and their Implications

Ultraluminous X-ray sources are believed to be associated with X-ray binaries, in which an accreting black hole generates X-ray luminosities in excess of 10 39 erg/s. The nature of the companion star and the underlying physics of the accretion process is not yet established with certainty. In particular, whether or not the accretion is super/sub Eddington is an open question, as is the mass of the companion star. We discuss the first two ULXs recently discovered in M31 and investigate the nature of their underlying sources. We present the X-ray observations for ULX-1 in detail and discuss its implications for its accretor. We also considered the positions of both ULX sources in the context of their hypothetical association with either High Mass X-ray Binaries and Low Mass X-ray Binaries. We construct a simple disk plus bulge model to test their association with starlight and use IR images from Spitzer to investigate their possible link to star formation. We find that the position of these two sources more strongly supports scenarios in which the companion is a high mass star. Using the data obtained with XMM-Newton, Swift and Chandra, we infer that the underlying source for ULX-1 is a 13 Msun black hole under the assumption that it is non-spinning. The combined study of X-ray properties and the spatial distribution presented in this thesis argue in favor of stellar mass black holes accreting at near Eddington rates from high mass companions

Comparison of Linear Method and Non Linear Method for Analysis of Heart Rate Variability using MatlabÂ

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Functional characterisation of the mesenchymal cell-derived extracellular matrix in myelodysplastic neoplasms

Myelodysplastic neoplasms (MDS) are a group of heterogeneous, clonal disorders characterised by ineffective haematopoiesis and peripheral blood cytopenia. MDS is highly progressive, difficult to treat, and is one of the most common blood cancers, affecting 4-5/100.000 people below the age of 70 and many more thereafter. Single or multiple driver gene mutations and chromosomal abnormalities in the haematopoietic compartment lead to MDS. These somatic gene mutations account for the dysregulation of epigenetic, DNA repair, cohesion complex, and spliceosome pathways. The International prognostic scoring system (IPSS) that was developed in 1997, revised (IPSS-R) in 2016 and updated in 2022 (IPSS-M) classifies MDS into low risk (LR-), intermediate (Int-), and high risk (HR-) groups. The haematopoietic disorder is accompanied by changes in the bone marrow microenvironment (BMME) and especially in mesenchymal cells (MSCs). BMME provides a supportive milieu for haematopoiesis and can be targeted by clinically available drugs such as AZA. The non cellular component of the BMME, the extracellular matrix (ECM), is a framework providing structural and biochemical support via cell-ECM interactions and the maintenance of growth factor gradients. To date, studies of bone marrow interactions in homeostasis and disease have focused largely on soluble and membrane-associated factors, while the involvement of the ECM in MDS and its response to therapy is underexplored. Therefore, this study aimed to characterise the MDS MSC derived ECM of both LR- and HR-MDS in comparison to that from healthy age matched donors in terms of composition, biophysical properties and functional haematopoietic support. This study also aimed to evaluate the impact of in vivo and in vitro AZA treatment on MDS MSC derived ECM. To investigate this, in vitro ECMs were generated by culturing of MSC monolayers on chemically prepared coverslips followed by decellularization using NH4OH and DNase-1 solution. The biophysical properties of the ECM were analysed using atomic force microscopy (AFM). Using targeted approaches, a selection of biochemical ECM components including glycoprotein (fibronectin), collagens and glycosaminoglycans (GAGs) were analysed in the various ECMs generated from the different MSC samples. AFM analysis revealed that MDS MSCs producer a softer ECM than the healthy donor MSCs, and that this difference becomes more prominent as the disorder progresses from LR-to HR- MDS. An increase in overall collagen content and a specific increase in collagens I and IV was observed in the ECM deposited by both LR- and HR-MDS MSCs when compared to healthy donor MSCs. Lectin staining revealed disease stage-specific differences in GAG composition: The levels of GAGs carrying N acetyl glucosamine and those carrying N-acetyl galactosamine sugars were both increased in ECM from LR-MDS, while ECM from HR-MDS retained high levels of N acetyl glucosamine but contained only low levels of N-acetyl galactosamine GAGs. The changes in N acetyl galactosamine and N acetyl glucosamine GAGs were further confirmed by chondroitin sulphate (CS) immunostaining, and hyaluronic acid (HA) ELISA respectively. Electrophoretic analysis revealed the presence of low molecular weight (LMW)-HA in one of the LR-MDS MSC derived ECM. Furthermore, the stimulation of MNCs with LMW-HA showed an increase in gene expression of pro-inflammatory cytokines like IL6 suggesting the possible involvement of LMW-HA in the inflammatory bone marrow state of LR-MDS. ECM derived from both LR- and HR-MDS MSCs had a reduced ability to support HSPC, as revealed by a loss of both polar morphology and subsequent colony-forming potential. The decreased rigidity of the ECM produced by MSCs from MDS patients was reversed in MSCs isolated from the patients post-AZA therapy. Similarly, direct exposure of cultured MDS MSCs to AZA also resulted in a corresponding increase in the rigidity of the ECM, although this remained lower than that observed from MDS MSCs isolated post-AZA therapy. A reduction in the collagen content of the ECM was only observed when using MSC from AZA-treated patients, but not following in vitro AZA treatment of MSCs from untreated patients. This indicated that the AZA-mediated restoration of ECM rigidity is an indirect result of effects in the context of the BMME and not on the MSCs alone. Interestingly, a few ECMs derived from MDS patients after AZA therapy had an improved ability to maintain functional HSPCs, as assessed by subsequent colony formation assay. Moreover, a polarized morphology of HSPCs cultured on the ECM derived from both in vivo and in vitro AZA-treated MDS MSCs, suggests a partial restoration of the HSPC behaviour on the AZA-treated MDS ECM. In conclusion, this study has demonstrated changes in the structure, collagen content, and GAG composition of ECM derived from MSCs from MDS patients compared to healthy donors. This study is one of the first to demonstrate an impact of MDS-derived ECM on both the morphology and function of HSPCs, supporting the relevance of the bone marrow ECM in haematological malignancies. The partial revision of the MDS ECM phenotype following in vivo AZA treatment suggests that the ECM itself may be a potential therapeutic target. An improved, in-depth understanding of the contribution of ECM to disease processes is therefore likely to enable us to find novel therapeutic targets to improve drug response in MDS in the future.Myelodysplastische Neoplasien (MDS) sind eine Gruppe heterogener, klonaler Erkrankungen, die durch ineffektive Hämatopoese und Zytopenie des peripheren Blutes gekennzeichnet sind. MDS sind hochgradig progressiv, schwer zu behandeln und gehören zu den häufigsten Blutkrebserkrankungen, von denen 4-5/100.000 Menschen unter 70 Jahren betroffen sind. Die Inzidenz steigt mit zunehmendem Alter deutlich an. MDS wird durch einzelne oder mehrfache Mutationen von Treibergenen und Chromosomenanomalien im hämatopoetischen Kompartiment verursacht. Diese somatischen Genmutationen sind für die Dysregulation von epigenetischen, DNA-Reparatur-, Kohäsionskomplex- und Spleißosomen-Signalwegen verantwortlich. Das Internationale Prognosesystem (IPSS) wurde 1997 entwickelt, 2016 überarbeitet (IPSS-R) und 2022 aktualisiert (IPSS M), um MDS in Gruppen mit niedrigem Risiko (LR-), mittlerem (Int ) und hohem Risiko (HR-) einzuteilen. Die hämatopoetische Erkrankung geht mit Veränderungen in der Mikroumgebung des Knochenmarks (BMME) einher, insbesondere bei mesenchymalen Zellen (MSCs). Das BMME bietet ein unterstützendes Milieu für die Hämatopoese und kann durch klinisch verfügbare Medikamente wie AZA beeinflusst werden. Die nichtzelluläre Komponente der BMME, die extrazelluläre Matrix (ECM), ist ein Gerüst, das durch Zell-ECM-Interaktionen und die Aufrechterhaltung von Wachstumsfaktorgradienten strukturelle und biochemische Unterstützung bietet. Bislang haben sich Studien über die Interaktionen im Knochenmark bei Homöostase und Krankheit hauptsächlich auf lösliche und membranassoziierte Faktoren konzentriert, während die Beteiligung der ECM an MDS und ihre Reaktion auf die Therapie noch nicht ausreichend erforscht ist. Daher zielte diese Studie darauf ab, die aus MDS-MSCs abgeleitete ECM sowohl bei LR- als auch bei HR-MDS im Vergleich zu der von gesunden, altersgleichen Spendern zu charakterisieren, und zwar hinsichtlich der Zusammensetzung, der biophysikalischen Eigenschaften und der funktionellen hämatopoetischen Unterstützung. Ziel dieser Studie war es auch, die Auswirkungen einer in vivo und in vitro AZA-Therapie auf die aus MDS-MSCs stammende ECM zu untersuchen. Hierfür wurden in vitro ECMs durch Kultivierung von MSC-Monolayern auf chemisch-präparierten-Deckgläsern und anschließender Dezellularisierung mit NH4OH und DNase-1-Lösung erzeugt. Die biophysikalischen Eigenschaften der ECM wurden mittels Rasterkraftmikroskopie (AFM) analysiert. Mit gezielten Ansätzen wurde eine Auswahl biochemischer ECM-Komponenten, darunter Glykoproteine (Fibronektin), Kollagene und Glykosaminoglykane (GAGs), in den ECMs analysiert. Die AFM-Analyse ergab eine weichere ECM, die von MDS-MSCs im Vergleich zu gesunden Spender-MSCs gebildet wurde, was mit dem Fortschreiten der Erkrankung von LR- zu HR-MDS noch deutlicher wurde. Sowohl in LR-MDS- als auch in HR-MDS-ECMs wurde im Vergleich zu gesunden Spender-ECMs ein Anstieg des Gesamtkollagengehalts und eine spezifische Zunahme der Kollagene I und IV beobachtet. Darüber hinaus zeigte die Lektinfärbung krankheitsspezifische Unterschiede in der GAG-Zusammensetzung: Der Gehalt an N-Acetylglucosamin-tragenden GAGs und an N-Acetylgalactosamin-tragenden GAGs war in der ECM von LR-MDS erhöht, während die ECM von HR-MDS einen hohen Gehalt an N-Acetylglucosamin, aber nur einen geringen Gehalt an N-Acetylgalactosamin-GAGs aufwies. Die Veränderungen bei den N-Acetyl-Galactosamin- und N-Acetyl-Glucosamin-GAGs wurden durch Chondroitinsulfat (CS)-Immunfärbung bzw. Hyaluronsäure (HA) ELISA weiter bestätigt. Eine Elektrophoretische Analyse zeigte das Vorhandensein von niedermolekularem (LMW)-HA in einer der von LR-MDS-MSCs stammenden ECM. Darüber hinaus zeigte die Stimulierung von mononuklearen Zellen mit LMW-HA einen Anstieg der Genexpression von pro-inflammatorischen Zytokinen wie IL6, was auf eine Rolle von LMW-HA im entzündlichen Zustand des Knochenmarks von LR-MDS hindeutet. Darüber hinaus wies die ECM von LR- und von HR-MDS, eine verminderte Fähigkeit, hämatopoetische Stammvorläuferzellen (HSPCs) zu unterstützen, auf. Dies zeigte sich in einem Verlust sowohl der polaren Morphologie von HSPCs als auch des anschließenden koloniebildenden Potenzials selbiger. Darüber hinaus wurde die verringerte Steifigkeit der ECM von MDS-MSCs, die nach der AZA-Therapie aus den Patienten isoliert wurden, umgekehrt. In ähnlicher Weise führte die direkte Exposition von kultivierten MDS-MSCs mit AZA zu einer entsprechenden Erhöhung der Steifigkeit der ECM. Diese war jedoch geringer als bei den nach der AZA-Therapie isolierten MDS-MSCs. Die Verringerung des Kollagengehalts der ECM wurde nur in der in vivo mit AZA behandelten MSC-ECM beobachtet, nicht aber in den in vitro mit AZA behandelten Proben. Dies deutet darauf hin, dass die AZA-vermittelte Wiederherstellung der ECM-Steifigkeit ein Ergebnis der indirekten Wirkung von AZA im Knochenmark ist und eventuell vom MDS-Klon ausgeht. Interessanterweise wurde bei einigen ECMs von MDS-Patienten nach der AZA-Therapie eine Verbesserung der Koloniebildung hierauf- kultivierter HSPCs beobachtet. Darüber hinaus deutet eine polarisierte Morphologie von HSPCs, die auf der ECM von in vivo und in vitro AZA-behandelten MDS-MSCs vorkultiviert wurden, auf eine teilweise Wiederherstellung des Verhaltens von HSPCs auf der AZA-behandelten MDS-ECM hin. Zusammenfassend lässt sich sagen, dass diese Studie Veränderungen in der Struktur, im Kollagengehalt und in der GAG-Zusammensetzung zwischen der ECM von MDS-MSCs und der ECM von gesunden MSCs nachgewiesen hat. Dies ist auch eine der ersten Studien, die einen Einfluss der aus MDS-MSCs stammenden ECM auf die Morphologie und Funktion von HSPCs zeigt. Dies weist auf die Rolle der ECM bei der Entstehung hämatologischer Malignome hin. Darüber hinaus deutet die teilweise Korrektur des MDS-ECM-Phänotyps nach einer in vivo AZA-Behandlung darauf hin, dass die ECM selbst ein potenzielles therapeutisches Ziel sein könnte. Ein besseres und tieferes Verständnis des Beitrags der ECM zu MDS-Krankheitsprozessen wird es uns daher ermöglichen, neue therapeutische Ziele zu finden, um das Ansprechen auf Medikamente verbessern zu könne