Generalized line graphs: Cartesian products and complexity of recognition

Putting the concept of line graph in a more general setting, for a positive integer k the k-line graph Lk(G) of a graph G has the Kk-subgraphs of G as its vertices, and two vertices of Lk(G) are adjacent if the corresponding copies of Kk in G share k-1 vertices. Then, 2-line graph is just the line graph in usual sense, whilst 3-line graph is also known as triangle graph. The k-anti-Gallai graph Δk(G) of G is a specified subgraph of Lk(G) in which two vertices are adjacent if the corresponding two Kk-subgraphs are contained in a common Kk+1-subgraph in G. We give a unified characterization for nontrivial connected graphs G and F such that the Cartesian product G□F is a k-line graph. In particular for k = 3, this answers the question of Bagga (2004), yielding the necessary and suficient condition that G is the line graph of a triangle-free graph and F is a complete graph (or vice versa). We show that for any k ≥ 3, the k-line graph of a connected graph G is isomorphic to the line graph of G if and only if G = Kk+2. Furthermore, we prove that the recognition problem of k-line graphs and that of k-anti-Gallai graphs are NP-complete for each k ≥ 3. © 2015, Australian National University. All rights reserved

Morphological evidence for enhanced kisspeptin and neurokinin B signaling in the infundibular nucleus of the aging man.

Peptidergic neurons synthesizing kisspeptin (KP) and neurokinin B (NKB) in the hypothalamic infundibular nucleus have been implicated in negative sex steroid feedback to GnRH neurons. In laboratory rodents, testosterone decreases KP and NKB expression in this region. In the present study, we addressed the hypothesis that the weakening of this inhibitory testosterone feedback in elderly men coincides with enhanced KP and NKB signaling in the infundibular nucleus. This central hypothesis was tested in a series of immunohistochemical studies on hypothalamic sections of male human individuals that were divided into arbitrary "young" (21-49 yr, n = 11) and "aged" (50-67 yr, n = 9) groups. Quantitative immunohistochemical experiments established that the regional densities of NKB-immunoreactive (IR) perikarya and fibers, and the incidence of afferent contacts they formed onto GnRH neurons, exceeded several times those of the KP-IR elements. Robust aging-dependent enhancements were identified in the regional densities of KP-IR perikarya and fibers and the incidence of afferent contacts they established onto GnRH neurons. The abundance of NKB-IR perikarya, fibers, and axonal appositions to GnRH neurons also increased with age, albeit to lower extents. In dual-immunofluorescent studies, the incidence of KP-IR NKB perikarya increased from 36% in young to 68% in aged men. Collectively, these immunohistochemical data suggest an aging-related robust enhancement in central KP signaling and a moderate enhancement in central NKB signaling. These changes are compatible with a reduced testosterone negative feedback to KP and NKB neurons. The heavier KP and NKB inputs to GnRH neurons in aged, compared with young, men may play a role in the enhanced central stimulation of the reproductive axis. It requires clarification to what extent the enhanced KP and NKB signaling upstream from GnRH neurons is an adaptive response to hypogonadism or, alternatively, a consequence of a decline in the androgen sensitivity of KP and NKB neurons

Searching for new white dwarf pulsators for TESS observations at Konkoly Observatory

We present the results of our survey searching for new white dwarf pulsators for observations by the TESS space telescope. We collected photometric time-series data on 14 white dwarf variable candidates at Konkoly Observatory, and found two new bright ZZ Ceti stars, namely EGGR 120 and WD 1310+583. We performed a Fourier analysis of the datasets. In the case of EGGR 120, which was observed on one night only, we found one significant frequency at 1332μHz with 2.3 mmag amplitude. We successfully observed WD 1310+583 on eight nights, and determined 17 significant frequencies in the whole dataset. Seven of them seem to be independent pulsation modes between 634 and 2740μHz, and we performed preliminary asteroseismic investigations of the star utilizing six of these periods. We also identified three new light variables on the fields of white dwarf candidates: an eclipsing binary, a candidate delta Scuti/beta Cephei and a candidate W UMa-type star

The Role of Cdc42 and Gic1 in the Regulation of Septin Filament Formation and Dissociation

Septins are guanine nucleotide-binding proteins that polymerize into filamentous and higher-order structures. Cdc42 and its effector Gic1 are involved in septin recruitment, ring formation and dissociation. The regulatory mechanisms behind these processes are not well understood. Here, we have used electron microscopy and cryo electron tomography to elucidate the structural basis of the Gic1-septin and Gic1-Cdc42-septin interaction. We show that Gic1 acts as a scaffolding protein for septin filaments forming long and flexible filament cables. Cdc42 in its GTP-form binds to Gic1, which ultimately leads to the dissociation of Gic1 from the filament cables. Surprisingly, Cdc42-GDP is not inactive, but in the absence of Gic1 directly interacts with septin filaments resulting in their disassembly. We suggest that this unanticipated dual function of Cdc42 is crucial for the cell cycle. Based on our results we propose a novel regulatory mechanism for septin filament formation and dissociation. DOI: http://dx.doi.org/10.7554/eLife.01085.00

Interplay of drug transporters P-glycoprotein (MDR1), MRP1, OATP1A2 and OATP1B3 in passage of maraviroc across human placenta

Special attention is required when pharmacological treatment is indicated for a pregnant woman. P-glycoprotein (MDR1) is a well-known transporter localized in the maternal blood-facing apical membrane of placental syncytiotrophoblast and is considered to play an important role in protecting the developing fetus. Maraviroc, a MDR1 substrate that is registered for treatment of HIV infection, shows a low toxicity profile, suggesting favorable tolerability also if administered to pregnant women. Nevertheless, there is only poor understanding to date regarding the extent to which it permeates across the placental barrier and what are the transport mechanisms involved. Endeavoring to clarify the passage of maraviroc across placenta, we used in this study the method of closed-circuit perfusion of maraviroc across human placental cotyledon. The data obtained confirmed slight involvement of MDR1, but they also suggest possible interaction with other transport system(s) working in the opposite direction from that of MDR1. Complementary in vitro studies, including cellular experiments on choriocarcinoma BeWo cells as well as transporter-overexpressing MDCKII and A431 cell lines and accumulation in placental fresh villous fragments, revealed maraviroc transport by MRP1, OATP1A2, and OATP1B3 transporters. Based on mRNA expression data in the placental tissue, isolated trophoblasts, and fetal endothelial cells, especially MRP1 and OATP1A2 seem to play a crucial role in cooperatively driving maraviroc into placental tissue. By the example of maraviroc, we show here the important interplay of transporters in placental drug handling and its possibility to overcome the MDR1-mediated efflux. © 2020 The Author

Pohjoismansin peruskurssi

Tämä aineisto on suunnattu soveltuvin osin viiden opintopisteen laajuisen mansin kielen alkeiskurssin kurssimateriaaliksi. Kurssin tavoitteena on oppia pohjoismansin perussanastoa sekä morfologian ja syntaksin perusteet: aineiston avulla voi saavuttaa Eurooppalaisen viitekehyksen tason B1. Kurssin jälkeen opiskelija pystyy ymmärtämään ja tuottamaan yksinkertaista mansinkielistä tekstiä sekä käymään lyhyitä keskusteluja mansiksi. Opiskelija tuntee ja tunnistaa tavallisimmat morfologiset päätteet ja osaa käyttää niitä kielen rakenteissa. Opiskelija hallitsee mansin kielen perussanaston ja osaa tarvittaessa etsiä sanoja sanakirjoista ja verkkoaineistoista. Materiaali on alun perin koottu mansin kielen alkeiskurssille Helsingin yliopiston suomalais-ugrilaisen kielentutkimuksen oppinaineen piirissä keväällä 2019. Tuolloin FT Susanna Virtanen aloitti yksikössä mansin kielen opetuksen vaiheessa, jossa se oli ollut tauolla vuosia. Hän päätti tehdä kurssien oppimateriaalit itse, koska ajantasaisia valmiita materiaaleja ei ollut. Niin syntyi ensin irrallisia luentomonisteita, joita alettiin kehittää jäntevämmäksi ja yhtenäisemmäksi kurssimateriaaliksi mm. opiskelijapalautteen avulla. Keväällä 2020 työhön liittyivät myös maisteri Csilla Horváth ja mansin kielen opettajan tutkinnon suorittanut toimittaja Tamara Merova, joiden panos työn onnistumiseen on ollut korvaamaton. Aineiston on tarkoitus täyttää akuutti ajantasaisen opetusmateriaalin tarve ja tuoda osansa suomalais-ugrilaisen kielentutkimuksen alan yliopistopedagogiseen kehitykseen. Mansin kielen opetuksella on Helsingin yliopistossa pitkät perinteet, mutta oppimateriaalit eivät ole kehittyneet ajan mukana. Rautaesiripun aikana ainoa saatavilla oleva aineisto oli 1800–1900-lukujen taitteessa kerätyt kansanrunoustekstit. Niiden käyttöä jatkettiin vielä rajojen avauduttuakin, koska uutta kirjallista aineistoa oli edelleen niukasti saatavilla. Länsimaisen tradition mukaisia oppimateriaaleja ei ole juuri tuotettu yliopistotasoiseen opetukseen. Nyt kuitenkin tilanne on korjaantumassa: tämän materiaalin toimittajat ovat saaneet Koneen säätiöltä rahoituksen alkeisoppikirjan toimittamiseen. Oppikirjan odotetaan ilmestyvän Suomalais-Ugrilaisen Seuran kustantamana vuonna 2023. Materiaaliin on koottu teoreettinen selostus jokaisesta kielioppiaiheesta. Aiheita havainnollistetaan käytännön esimerkein. Samalla opitaan mansin kielen perussanastoa. Jokaisen teoriaosuuden jälkeen rakenteita ja sanastoa harjoitellaan havainnollisin tehtävin. Kielenainekset esitetään kyrillistä kirjaimistoa käyttäen, koska se on mansiyhteisön itse käyttämä kirjoitustyyli. Kirjan tekstikappaleet ja kieliesimerkit on poimittu mm. mansin kielen lukemistoista ja ajankohtaisista sanomalehtiartikkeleista (ks. lähdeluettelo). Osa esimerkeistä on toimittajien itse luomia. Aineiston kuvitus on Papunetin ilmaisesta kuvapankista. Aineistoa käyttävän opettajan suositellaan valitsemaan aineistosta kurssin laajuuteen soveltuvat aihealueet. Esim. kappaleiden 13, 14 ja 15 aiheet voi jättää myös myöhempien kurssien teemoiks

NR2B receptor blockade inhibits pain-related sensitization of amygdala neurons

Pain-related sensitization and synaptic plasticity in the central nucleus of the amygdala (CeA) depend on the endogenous activation of NMDA receptors and phosphorylation of the NR1 subunit through a PKA-dependent mechanism. Functional NMDA receptors are heteromeric assemblies of NR1 with NR2A-D or NR3A, B subunits. NMDA receptors composed of NR1 and NR2B subunits have been implicated in neuroplasticity and are present in the CeA. Here we used a selective NR2B antagonist (Ro-256981) to determine the contribution of NR2B-containing NMDA receptors to pain-related sensitization of CeA neurons. Extracellular single-unit recordings were made from CeA neurons in anesthetized adult male rats before and during the development of an acute arthritis. Arthritis was induced in one knee joint by intraarticular injections of kaolin and carrageenan. Brief (15 s) mechanical stimuli of innocuous (100–500 g/30 mm2) and noxious (1000–2000 g/30 mm2) intensity were applied to the knee and other parts of the body. In agreement with our previous studies, all CeA neurons developed increased background and evoked activity after arthritis induction. Ro-256981 (1, 10 and 100 μM; 15 min each) was administered into the CeA by microdialysis 5–6 h postinduction of arthritis. Ro-256981 concentration-dependently decreased evoked responses, but not background activity. This pattern of effect is different from that of an NMDA receptor antagonist (AP5) in our previous studies. AP5 (100 μM – 5 mM) inhibited background activity and evoked responses. The differential effects of AP5 and Ro-256981 may suggest that NMDA receptors containing the NR2B subunit are important but not sole contributors to pain-related changes of CeA neurons

Foghiányokat kísérő egyszerű nukleotid polimorfizmusok hypodontiában = Single nucleotide polymorphisms in hypodontia

Komplex megközelítéssel tanulmányoztuk a fogcsírahiányban feltehetőleg résztvevő több egyszerű nukleotid polimorfizmust (SNP) a magyar populációban. A PAX9, az MSX1, az FGFR1, az IRF6 és az AXIN2 nyolc polimorfizmusát vizsgáltuk 192 hipodonciás, 17 oligodonciás és 260 egészséges önkéntes esetében. Az eset-kontroll analízisben mind az allél, mind a genotípus asszociációk gyakoriságát, valamint a haplotípus szintű asszociációk gyakoriságát tanulmányoztuk. Többváltozós Bayes hálózat alapú többszintű valószínűségi analízist (BN-BMLA) és logisztikus regressziót végeztünk. A hagyományos statisztikák azt mutatták, hogy a PAX9 -912-es SNP és az MSX1 SNP megváltoztatta a hipodoncia előfordulását, de korrekció után a hatások csak marginális tendenciát mutattak. A többszörös hipotézis tesztelésre alkalmasabb BN-BMLA analízist használva a PAX9 SNP-k szinergikus hatást adtak. Ezt megerősítette más többváltozós analízis is, és az összefüggés szignifikáns maradt a többszörös hipotézis tesztelés után is . A PAX9-1031-A-PAX9-912-T haplotípus volt a legjelentősebb kombináció ami csírahiányt okozott. PAX9 és MSX1 között az együtthatás gyengébb volt, míg más SNP-nek nem volt hatása a hipodonciára. Komplex analízisünk megmutatta a PAX9 és MSX1-es SNP-k együtthatásának fontos szerepét a fogcsírahiányra, míg az IRF6, FGFR1 és Axin2 SNP-knek nem volt detektálható szerepe a magyar populációban. A mi eredményeink is rávilágítanak a populációk közötti eltérések jelentőségére. | We studied the role of multiple single nucleotide polymorphisms (SNP) in tooth agenesis in the Hungarian population using a complex approach. Eight SNPs of PAX9, MSX1, FGFR1, IRF6 and AXIN2 were studied in 192 hypodontia and 17 oligodontia cases and in 260 healthy volunteers. Case-control analysis was performed to test both allelic and genotypic associations as well as associations at the level of haplotypes. Multivariate exploratory Bayesian network based multilevel analysis of relevance (BN-BMLA) as well as logistic regression analysis were performed. Conventional statistics showed that PAX9 SNP -912 C/T and the MSX1 SNP changed the incidence of hypodontia, although after correction the effects were only borderline tendencies. Using a statistical analysis better suited for handling multiple hypotheses, the BN-BMLA, PAX9 SNPs clearly showed a synergistic effect. This was confirmed by other multivariate analyses and it remained significant after corrections for multiple hypothesis testing. The PAX9-1031-A-PAX9-912-T haplotype was the most relevant combination causing hypodontia. Interaction was weaker between PAX9 and MSX1, while other SNPs had no joint effect on hypodontia. Our complex analysis shows the important role of PAX9 and MSX1 SNPs and of their interactions in tooth agenesis, while IRF6, FGFR1 and AXIN2 SNPs had no detectable role in the Hungarian population. Our results also reveal the variations of risk factors in hypodontia