240 research outputs found

    Mechanism of Enhancement in Electromagnetic Properties of MgB2 by Nano SiC Doping

    Get PDF
    A comparative study of pure, SiC, and C doped MgB2 wires has revealed that the SiC doping allowed C substitution and MgB2 formation to take place simultaneously at low temperatures. C substitution enhances Hc2, while the defects, small grain size, and nanoinclusions induced by C incorporation and low-temperature processing are responsible for the improvement in Jc. The irreversibility field (Hirr) for the SiC doped sample reached the benchmarking value of 10 T at 20 K, exceeding that of NbTi at 4.2 K. This dual reaction model also enables us to predict desirable dopants for enhancing the performance properties of MgB2

    EVALUATION OF SOILS IN SPLIT-DALMATIA COUNTY FOR THE NEEDS OF IRRIGATION

    Get PDF
    Istraživanje i vrjednovanje tala Splitsko-dalmatinske županije jedno je od brojnih u državnoj strategiji izrade planova natapanja. Sve veća suša u razvoju poljoprivrede utječe na proizvodnost poljoprivredne proizvodnje u tom mediteranskom okružju. Temeljni cilj u ovom radu je bio sagledati zemljišne resurse pogodne za natapanje i izdvojiti oranične površine gdje bi ta hidrotehnička mjera dala najveće rezultate. Osnovna metoda vrjednovanja je procjena pogodnosti tala za potrebe natapanja (FAO, 1976; Vidaček, 1981). Analiza je izvršena pomoću GIS tehnologije, program ArcView. Na temelju analize pedoloških istraživanja semidetaljnog karaktera utvrdili smo sljedeće: Splitsko-dalmatinska županija ima površinu od 4.539 km2. Od toga na poljoprivredne površine otpada 2.177 km2 ili 48%. Šume su po površini najzastupljenije i zauzimaju 2.244 km2 ili 49,4%. Naselja i okućnice zauzimaju 90 km2 ili 2,0%. Vodene površine zauzimaju 29 km2 ili 0,6%. Najzastupljenija tla županije su smeđa tla na vapnencu ili dolomitu s 52.485 ha i vapneno dolomitna crnica s 42.027 ha, koja zbog stjenovitosti i nagiba spadaju u trajno nepogodna tla za natapanje. Od pogodnih tala najzastupljenija su antropogena tla u raznim oblicima krša (42.258 ha). Najbolja tla za oranice i vrtove su hidromeliorirana (3.649 ha) i aluvijalna (3.068 ha), a tla koja u tom kraju potencijalno najviše vrijede su močvarno glejna tla (3.337 ha). Pogodnih tala prvog prioriteta za natapanje s potrebnim većim ili manjim mjerama agromelioracija ima 92.003 ha, a drugog prioriteta za hidro i/ili agromelioracije u primjeni natapanja 6.001 ha. Trajno nepogodnih tala za natapanje u okviru poljoprivrednih površina (prvenstveno pašnjaci i livade) ima 119.663 ha.Investigation and evaluation of soils in Split-Dalmatia County are among numerous such investigations in the national strategy for planning irrigation. Increasingly frequent droughts affect agricultural production in this Mediterranean region. The principal aim of this work was to review the land resources suitable for irrigation and separate cropping areas where this hydrotechnical measure would render optimal results. The basic evaluation method is assessment of soil suitability for irrigation (FAO, 1976; Vidaček, 1981). Analysis was done using the GIS technology, program ArcView. Pedological investigations of semi-detailed character provided the following data: Split-Dalmatia County has an area of 4,539 km2. In this number, agricultural areas account for 2,177 km2 or 48%. Forests cover the largest area of 2,244 km2 or 49.4%. Settlements and house lots occupy 90 km2 or 2.0%. Water areas cover 29 km2 or 0.6%. The most wide-spread soils in this county are calcocambisols with 52,485 ha and calcomelanosols with 42,027 ha, which due to their rockiness and slope are permanently not suitable for irrigation. The most frequent suitable soils are anthropogenic soils in various karst forms (42,258 ha). Best soils for plough-fields and gardens are hydroameliorated (3,649 ha) and alluvial (3,068 ha) soils, while the potentially most valuable soils in the region are gley amphigley soils (3,337 ha). There are 92,003 ha of suitable soils of the first priority for irrigation requiring larger or smaller agroamelioration measures, and 6,001 ha of the second priority for hydro and/or agroamelioration when applying irrigation. There are 119,663 ha of permanently not suitable soils for irrigation within agricultural areas (primarily pastures and meadows)

    WATER DEFICIT ANALYSIS IN VARIOUS CROPS

    Get PDF
    U radu se razmatra manjak vode u tlu za područje Zagreba za obradiva tla (tipa: aluvij i semiglej) te za najčešće uzgajane poljoprivredne kulture (silažni kukuruz, kupus, paprika, salata, rajčica, kukuruz, jabuka itd.). Pogodnost tala je određena FAO metodom. Klimatološke karakteristike područja s aspekta navodnjavanja određene su uporabom 20-godišnjih nizova meteoroloških podataka i pedoloških podataka te indeksa faza razvoja biljaka. Referentna evapotranspiracija (ETo) izračunata je prema metodi Penman-Montheitha. Efektivne oborine izračunate su metodom USBR iz vrijednosti srednjih mjesečnih prosječnih oborina kao i iz količine mjesečnih oborina koje su razgraničene donjim kvartilom. Bilanca vode u tlu za svaku kulturu izračunata je prema metodi Palmera. Dobiveni rezultati pokazuju da su potrebe kultura za vodom različite, a ukupni nedostatak vode ovisi o količini i sezonskom rasporedu oborina i hidropedološkim značajkama tala. Za svaku kulturu izračunat je manjak vode za višegodišnji prosjek oborina i za sušne mjesece, koji su razgraničeni donjim kvartilom količine oborine. Može se zaključiti da je navodnjavanje potrebna mjera u uzgoju navedenih kultura na navedenim tipovima tala na području Zagreba.The paper deals with water a deficit in arable soils of the Zagreb region (types: calacaric fluvisol and semigley) and for the most common agricultural crops grown (silage maize, cabbage, bell pepper, lettuce, tomato, maize, apple, etc.). Soil suitability was assessed by the FAO method. Climatological characteristics of the region, from the aspect of irrigation, were assessed using 20-year series of meteorological and pedological data, and indices of plant development stages. Reference evapotranspiration (ETo) was calculated by the Penman-Monteith method. Effective precipitation was calculated by the USBR method from the values of mean monthly average precipitation as well as from the amounts of monthly precipitation, separated by the lower quartile. Palmer’s method was used to calculate soil water balance for each crop. The results show that different crops have different water requirements, the total water deficit depending on the amount and seasonal distribution of precipitation and on the soil hydropedological characteristics. The water deficit was calculated for each crop with respect to the long-term precipitation average as well as for droughty months, separated by the lower quartile of the precipitation amount. It is concluded that irrigation is a necessary measure for the production of the studied crops on the said soil types in the Zagreb region

    Binding of SGTA to Rpn13 selectively modulates protein quality control

    Get PDF
    YesRpn13 is an intrinsic ubiquitin receptor of the 26S proteasome regulatory subunit that facilitates substrate capture prior to degradation. Here we show that the C-terminal region of Rpn13 binds to the tetratricopeptide repeat (TPR) domain of SGTA, a cytosolic factor implicated in the quality control of mislocalised membrane proteins (MLPs). The overexpression of SGTA results in a substantial increase in steady-state MLP levels, consistent with an effect on proteasomal degradation. However, this effect is strongly dependent upon the interaction of SGTA with the proteasomal component Rpn13. Hence, overexpression of the SGTA-binding region of Rpn13 or point mutations within the SGTA TPR domain both inhibit SGTA binding to the proteasome and substantially reduce MLP levels. These findings suggest that SGTA can regulate the access of MLPs to the proteolytic core of the proteasome, implying that a protein quality control cycle that involves SGTA and the BAG6 complex can operate at the 19S regulatory particle. We speculate that the binding of SGTA to Rpn13 enables specific polypeptides to escape proteasomal degradation and/or selectively modulates substrate degradation.BBSRC [grant number: BB/L006510/1] and the Wellcome Trust [grant number: 092107/Z/10/Z]. K.K. was supported by the UPStream network [EU, FP7, ITN project 290257

    FBXL4 ubiquitin ligase deficiency promotes mitophagy by elevating NIX levels

    Get PDF
    Selective autophagy of mitochondria, mitophagy, is linked to mitochondrial quality control and as such is critical to a healthy organism. We have used a CRISPR/Cas9 approach to screen human E3 ubiquitin ligases for influence on mitophagy under both basal cell culture conditions and upon acute mitochondrial depolarization. We identify two cullin-RING ligase substrate receptors, VHL and FBXL4, as the most profound negative regulators of basal mitophagy. We show that these converge, albeit via different mechanisms, on control of the mitophagy adaptors BNIP3 and BNIP3L/NIX. FBXL4 restricts NIX and BNIP3 levels via direct interaction and protein destabilization, while VHL acts through suppression of HIF1α-mediated transcription of BNIP3 and NIX. Depletion of NIX but not BNIP3 is sufficient to restore mitophagy levels. Our study contributes to an understanding of the aetiology of early-onset mitochondrial encephalomyopathy that is supported by analysis of a disease-associated mutation. We further show that the compound MLN4924, which globally interferes with cullin-RING ligase activity, is a strong inducer of mitophagy, thus providing a research tool in this context and a candidate therapeutic agent for conditions linked to mitochondrial dysfunction

    The degradation of p53 and its major E3 ligase Mdm2 is differentially dependent on the proteasomal ubiquitin receptor S5a.

    Get PDF
    p53 and its major E3 ligase Mdm2 are both ubiquitinated and targeted to the proteasome for degradation. Despite the importance of this in regulating the p53 pathway, little is known about the mechanisms of proteasomal recognition of ubiquitinated p53 and Mdm2. In this study, we show that knockdown of the proteasomal ubiquitin receptor S5a/PSMD4/Rpn10 inhibits p53 protein degradation and results in the accumulation of ubiquitinated p53. Overexpression of a dominant-negative deletion of S5a lacking its ubiquitin-interacting motifs (UIM)s, but which can be incorporated into the proteasome, also causes the stabilization of p53. Furthermore, small-interferring RNA (siRNA) rescue experiments confirm that the UIMs of S5a are required for the maintenance of low p53 levels. These observations indicate that S5a participates in the recognition of ubiquitinated p53 by the proteasome. In contrast, targeting S5a has no effect on the rate of degradation of Mdm2, indicating that proteasomal recognition of Mdm2 can be mediated by an S5a-independent pathway. S5a knockdown results in an increase in the transcriptional activity of p53. The selective stabilization of p53 and not Mdm2 provides a mechanism for p53 activation. Depletion of S5a causes a p53-dependent decrease in cell proliferation, demonstrating that p53 can have a dominant role in the response to targeting S5a. This study provides evidence for alternative pathways of proteasomal recognition of p53 and Mdm2. Differences in recognition by the proteasome could provide a means to modulate the relative stability of p53 and Mdm2 in response to cellular signals. In addition, they could be exploited for p53-activating therapies. This work shows that the degradation of proteins by the proteasome can be selectively dependent on S5a in human cells, and that this selectivity can extend to an E3 ubiquitin ligase and its substrate

    N4BP1 functions as a dimerization-dependent linear ubiquitin reader which regulates TNF signalling

    Get PDF
    AbstractSignalling through TNFR1 modulates proinflammatory gene transcription and programmed cell death, and its impairment causes autoimmune diseases and cancer. NEDD4-binding protein 1 (N4BP1) is a critical suppressor of proinflammatory cytokine production that acts as a regulator of innate immune signalling and inflammation. However, our current understanding about the molecular properties that enable N4BP1 to exert its suppressive potential remain limited. Here, we show that N4BP1 is a novel linear ubiquitin reader that negatively regulates NFκB signalling by its unique dimerization-dependent ubiquitin-binding module that we named LUBIN. Dimeric N4BP1 strategically positions two non-selective ubiquitin-binding domains to ensure preferential recognition of linear ubiquitin. Under proinflammatory conditions, N4BP1 is recruited to the nascent TNFR1 signalling complex, where it regulates duration of proinflammatory signalling in LUBIN-dependent manner. N4BP1 deficiency accelerates TNFα-induced cell death by increasing complex II assembly. Under proapoptotic conditions, caspase-8 mediates proteolytic processing of N4BP1, resulting in rapid degradation of N4BP1 by the 26 S proteasome, and acceleration of apoptosis. In summary, our findings demonstrate that N4BP1 dimerization creates a novel type of ubiquitin reader that selectively recognises linear ubiquitin which enables the timely and coordinated regulation of TNFR1-mediated inflammation and cell death.</jats:p
    corecore