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From early history, builders, manufacturers, and engineers continued to develop composites of wide assortments of materials. Furthermore, chemical upheaval changed the composite development of plastics such as polyvinyl, polystyrene, etc., and reinforcement was reinforced essential to provide strength and rigidity. At present composites finds many applications in every aspects of day to day life. The utilization of raw materials like coal, baggase and agricultural wastes are used in large scales in industries for power generation and food production. The utilization of these fuels causing huge environmental pollution liberating in the form of ashes. These ashes can be utilized in effective way for manufacturing and structural applications with their incorporation in polymer matrix composites. To enhance the mechanical properties and in reducing the manufacturing cost, these industrial wastes plays a major role. The present research work mainly focuses on the influence of Coal Fly Ash (CFA), Silicon Carbide (SiC) and a mixture of CFA & SiC as filler materials on the mechanical behavior of Epoxy Glass fiber composite. Various types of composites are fabricated by manual hand lay-up process with varying weight percentages of the filler materials and epoxy resin as matrix material. The filler materials weight proportions are taken as 5%, 10% and 15%. The prepared composites are cut into tests specimen as per the ASTM standards of mechanical characterization. The mechanical properties of the composites (like Tensile strength (ASTM D3039/D3039M: 2017), Flexural strength (ASTM D790: 2015), Impact strength (ASTM D 229 el: 2019), Interlaminar shear strength (ASTM D2240: 2015), Hardness (ASTM D2240: 2015)) are determined by using corresponding testing machines and it is observed that the properties exhibited by the composites are enhanced with the incorporation of CFA, SiC & mixture of CFA and SiC when compared with the unfilled composites. So, these composites are considered a multifunctional composite material where the individual fillers are used in some applications and the combined proportions are used in different applications. They replace the existing materials that are very high in cost and cause more pollution at the time of manufacturing. These composites give the ability to improve and increase the efficiency, autonomy, and life expectancy of a structure.

Dispersing small amounts of solid nano particles into base-fluid has a significant impact on the thermo-physical properties of the base-fluid. These properties are utilized for effective capture and transportation of solar energy. This paper attempts key idea for harvesting solar energy by using alumina nanofluid in concentrating parabolic trough collectors. An experimental study is carried out to investigate the performance of a parabolic trough collector using Al2O3-H2O based nanofluid. Results clearly indicate that at same ambient, inlet temperatures, flow rate, concentration ratio etc. hike in thermal efficiency is around 5-10 % compared to the conventional Parabolic Trough Collector (PTC). Further, the effect of various parameters such as concentration ratio, receiver length, fluid velocity, volume fraction of nano particles has been studied. The different flow rates employed in the experiment are 2 ml/s, 4 ml/s and 6 ml/s. Volumetric concentration of 0.02%, 0.04% and 0.06% has been studied in the experiment. Surfactants are not introduced to avoid bubble formation. Tracking mode of parabolic trough collector is manual. Results also reveal that Al2O3-H2O based nanofluid has higher efficiency at higher flow rates.

The purpose of thermal energy storage systems (TES) is to store the heat energy supplied to it for a considerable time period and give the energy back when ever need arise. On many of occasions, part of the heat energy of various systems is unutilized. If this excess heat energy be stored in such systems as TESS, utilization of energy improves. If the use of such systems is widespread, fuel is conserved and national economy is saved.Different materials can be used in TESS to store heat energy and in the present work two such materials, which are popular phase change materials (PCM) namely (a) Paraffin (b) Stearic acid are used and subsequently the performance of the TESS is studied. The PCMs are used in the form of spherical capsules made up of high density poly ethylene (HDPE) of diameter 58 mm. Charging time and amount of heat energy recovered are studied for the two PCMs mentioned above and compared. Though paraffin as PCM gives little better heat energy recovery, performance of both the materials are almost the same. Hence as the cost of stearic acid is less when compared to paraffin on economical grounds and on ease of availability basis stearic acid has advantages over paraffin.

Unsteady magneto hydrodynamic (MHD) free convection flow of a viscous, incompressible and electrically conducting, well known non-Newtonian fluid named as Kuvshinski fluid past an infinite vertical porous plate in the presence of homogeneous chemical reaction, radiation absorption and heat source/sink is studied analytically. The plate is assumed to move with a constant velocity in the direction of fluid flow. A magnetic field of uniform strength is applied perpendicular to the plate, which absorbs the fluid with a suction that varies with time. The dimensionless governing equations are solved analytically using two terms harmonic and non-harmonic functions. The expressions for the fields of velocity, temperature and concentration are obtained. With the aid of these the expressions for skin friction, Nusselt number and Sherwood number are derived. The effects of various physical parameters on the flow quantities are studied through graphs and tables. For the validity, we have checked our results with previously published work and found in good agreement. Velocity decreases for an increase in visco elastic parameter α2, heat absorption coefficient φ, the chemical reaction parameter γ , the magnetic field parameter M, the Prandtl number Pr, the Schmidt number Sc, and increases for increase in Grashof number Gm, the radiation absorption parameter Q 1

The epithelium of the pulmonary airway is specially differentiated to provide defense against environmental insults, but also subject to dysregulated differentiation that results in lung disease. The current paradigm for airway epithelial differentiation is a one‐step program whereby a p63+basal epithelial progenitor cell generates a ciliated or secretory cell lineage, but the cue for this transition and whether there are intermediate steps are poorly defined. Here, we identify transcription factor Myb as a key regulator that permits early multilineage differentiation of airway epithelial cells. Myb+cells were identified as p63−and therefore distinct from basal progenitor cells, but were still negative for markers of differentiation. Myb RNAi treatment of primary‐culture airway epithelial cells and Mybgene deletion in mice resulted in a p63−population with failed maturation of Foxj1+ciliated cells as well as Scbg1a1+and Muc5ac+secretory cells. Consistent with these findings, analysis of whole genome expression of Myb‐deficient cells identified Myb‐dependent programs for ciliated and secretory cell differentiation. Myb+cells were rare in human airways but were increased in regions of ciliated cells and mucous cell hyperplasia in samples from subjects with chronic obstructive pulmonary disease. Together, the results show that a p63−Myb+population of airway epithelial cells represents a distinct intermediate stage of differentiation that is required under normal conditions and may be heightened in airway disease. StemCells2014;32:3245–3256

A Correction to this paper has been published: https://doi.org/10.1038/s41388-020-01632-1

Seminalplasmin, an antibacterial protein present in bovine seminal plasma, is shown to be a potent inhibitor of reverse transcriptases (RNA-dependent DNA nucleotidyltransferases). Seminalplasmin inhibits RNA-directed, hybrid-directed, and DNA-directed DNA-polymerizing activities of purified reverse transcriptase from avian myeloblastosis virus and from crude viral lysates of several retroviruses by binding to the enzyme, at least in the case of avian myeloblastosis virus. Seminalplasmin does not inhibit significantly DNA synthesis either by Escherichia coli DNA polymerase I, or a mammalian alpha-DNA polymerase. The presence of seminalplasmin in the seminal fluid could provide protection to the male and/or the female reproductive tract against retroviruses.

BackgroundMyelodysplastic Syndrome (MDS) is characterized by ineffective clonal hematopoiesis with peripheral blood cytopenias, leading to death from infection or bleeding. Azacitidine (AZA), a hypomethylating agent (HMA) is the standard of care for treatment of MDS patients (pts) with higher-risk MDS [Silverman LR, The Myelodysplastic Syndrome in Cancer Medicine, Editors: R.J. Bast, et al. 2017]. Responses to AZA occur in 50% of pts with significant effects on hematopoiesis ranging from improvement in a single lineage to complete restoration of blood counts and transfusion independence [Silverman LR, et al. Leukemia, 1993]. AZA treatment is associated with global DNA hypomethylation, including human endogenous retroviruses (HEV) which further activates innate immune signaling [Chiappinelli KB, et al.Cell, 2015]. The exact mechanism by which AZA improves hematopoiesis is unknown. AZA improves overall survival of pts, yet despite this, 100% of pts ultimately fail treatment with worsening cytopenias or transformation to leukemia [Silverman LR, et al. B. J Clin Oncol, 2002; Cancer, 2011]. Thus, understanding the mechanism of resistance and identification of targets which can reverse HMA failure and improve hematopoiesis in MDS pts is critical. Our clinical data demonstrate that AZA combined with Rigosertib (RIGO), a novel Ras mimetic that inhibits Ras/Raf signaling [Athuluri-Divakar SK, et al.Cell, 2016], yields a response rate of 54% of pts who were HMA failures [Navada SC, et al. EHA 2019]. The response was associated with significant improvement in hematopoiesis and represents a critical observation in overcoming the epigenetic clinical resistance phenotype. The precise mechanism that leads to reversal of the resistance phenotype is poorly understood.

ABSTRACTBlood-stage malaria vaccines that target single Plasmodium falciparumantigens involved in erythrocyte invasion have not induced optimal protection in field trials. Blood-stage malaria vaccine development has faced two major hurdles, antigenic polymorphisms and molecular redundancy, which have led to an inability to demonstrate potent, strain-transcending, invasion-inhibitory antibodies. Vaccines that target multiple invasion-related parasite proteins may inhibit erythrocyte invasion more efficiently. Our approach is to develop a receptor-blocking blood-stage vaccine against P. falciparumthat targets the erythrocyte binding domains of multiple parasite adhesins, blocking their interaction with their receptors and thus inhibiting erythrocyte invasion. However, with numerous invasion ligands, the challenge is to identify combinations that elicit potent strain-transcending invasion inhibition. We evaluated the invasion-inhibitory activities of 20 different triple combinations of antibodies mixed in vitroagainst a diverse set of six key merozoite ligands, including the novel ligands P. falciparumapical asparagine-rich protein (PfAARP), EBA-175 (PfF2), P. falciparumreticulocyte binding-like homologous protein 1 (PfRH1), PfRH2, PfRH4, and Plasmodiumthrombospondin apical merozoite protein (PTRAMP), which are localized in different apical organelles and are translocated to the merozoite surface at different time points during invasion. They bind erythrocytes with different specificities and are thus involved in distinct invasion pathways. The antibody combination of EBA-175 (PfF2), PfRH2, and PfAARP produced the most efficacious strain-transcending inhibition of erythrocyte invasion against diverse P. falciparumclones. This potent antigen combination was selected for coimmunization as a mixture that induced balanced antibody responses against each antigen and inhibited erythrocyte invasion efficiently. We have thus demonstrated a novel two-step screening approach to identify a potent antigen combination that elicits strong strain-transcending invasion inhibition, supporting its development as a receptor-blocking malaria vaccine.

Hematopoietic stem and progenitor cells are often undesired targets of chemotherapies, leading to hematopoietic suppression requiring careful clinical management. Whether microRNAs control hematopoietic injury response is largely unknown. We report an in vivo gain-of-function screen and the identification of miR-150 as an inhibitor of hematopoietic recovery upon 5-fluorouracil-induced injury. Utilizing a bone marrow transplant model with a barcoded microRNA library, we screened for barcode abundance in peripheral blood of recipient mice before and after 5-fluorouracil treatment. Overexpression of screen-candidate miR-150 resulted in significantly slowed recovery rates across major blood lineages, with associated impairment of bone marrow clonogenic potential. Conversely, platelets and myeloid cells from miR-150 null marrow recovered faster after 5-fluorouracil treatment. Heterozygous knockout of c-myb, a conserved target of miR-150, partially phenocopied miR-150-forced expression. Our data highlight the role of microRNAs in controlling hematopoietic injury response and demonstrate the power of in vivo functional screens for studying microRNAs in normal tissue physiology.

The differentiation of myeloid progenitors to mature, terminally differentiated cells is a highly regulated process. Here, we showed that conditional disruption of the c-mybproto-oncogene in adult mice resulted in dramatic reductions in CMP, GMP and MEP myeloid progenitors, leading to a reduction of neutrophils, basophils, monocytes and platelets in peripheral blood. In addition, c-mybplays a critical role at multiple stages of myeloid development, from multipotent CMP and bipotent GMP to unipotent CFU-G and CFU-M progenitor cells. c-mybcontrols the differentiation of these cells and is required for the proper commitment, maturation and normal differentiation of CMPs and GMPs. Specifically, c-mybregulates the precise commitment to the megakaryocytic and granulo-monocytic pathways and governs the granulocytic-monocytic lineage choice. c-mybis also required for the commitment along the granulocytic pathway for early myeloid progenitor cells and for the maturation of committed precursor cells along this pathway. On the other hand, disruption of the c-mybgene favors the commitment to the monocytic lineage, although monocytic development was abnormal with cells appearing more mature with atypical CD41 surface markers. These results demonstrate that c-mybplays a pivotal role in the regulation of multiple stages in adult myelogenesis.

Seven exclosure sites located on Mauna Kea, Hawaii and established in the 1960s and 70s were sampled to characterize long-term response of the mamane (Sophora chrysophylla) forest to protection from feral sheep grazing, and to assess impacts of non-native plant species and recurrent sheep presence on forest recovery. The forest provides essential habitat for an endangered bird, the palila (Loxoides bailleui). Vegetation was sampled inside exclosures during 1972–1976, 1998, and 2009, and also outside exclosures during 2009. Patterns of response varied among exclosures, but overall, mamane trees and native shrubs showed increasing cover between the 1970s and 1998, then a slowed rate of increase in cover or a decline between 1998 and 2009. Cover of native herbaceous vegetation showed variable trends between the 1970s and 1998, and then appeared to decline between 1998 and 2009. Mamane height class distributions inside exclosures indicated that recruitment was initially high but then declined as heights shifted toward larger size classes, and presumably an older age distribution. We found limited evidence of a negative effect of non-native species on forest regrowth, but the effect was not consistent over time or among sites. Recurrent sheep presence outside exclosures negatively affected mamane canopy density and perhaps tree density at all sites, and mamane condition at some sites. Our results indicate that the mamane forest has shown substantial regrowth inside exclosures at some sites, especially those protected the longest. However, these exclosures represent a small portion of the mamane forest. Sheep presence continues to impact mamane recovery outside exclosures, and thus habitat quality for the palila.

Although transplant centers are required to educate patients about kidney transplantation (KT) and living donation (LD), little is known about the educational format, and cultural and linguistic competence necessary for patients to make informed treatment decisions. This study surveyed US transplant administrators about education provided concerning KT and LD and culturally and linguistically competent care. Transplant administrators were invited to participate in an anonymous Internet‐based survey about education format, education providers, promoting LD, culturally and linguistically competent care and center characteristics. Most (61%) transplant administrators contacted (N = 280/461) completed the survey. Most administrators (91%) reported that their center provides any type of formal education in their pre‐KT evaluation. Education was mostly provided by: nurses (97%), social workers (72%) and surgeons (55%), and predominantly as one‐on‐one (80%) versus group discussions (60%). Education was primarily delivered through written materials (93%). Written educational materials in Spanish (86%) and the provision of interpreters (82%) were emphasized over educational sessions in Spanish (39%), or employing bilingual (51%) and bicultural staff (39%). Half (55%) promoted LD as the best option. Transplant centers need to take greater efforts to consistently provide appropriate education, promote LD, and provide culturally and linguistically competent care to ensure effective communication with all patients.

The importance of the CDK4 protein in human cancer first became evident following the identification of a germ line mutation in the Cdk4locus that predisposes humans to melanoma.  This mutation results in substitution of arginine with cysteine at position 24 (R24C).  In an earlier study, we introduced the R24C mutation into the Cdk4 locus of mice using Cre-loxP-mediated "knock-in" technology and observed a very low incidence of spontaneous melanomas in Cdk4R24C/R24C mice.  This suggested that additional oncogenic mutations might be required for development of melanomas.  Here we report an increased incidence of spontaneous cutaneous melanoma in mice expressing the oncogene HRAS(G12V) in melanocytes on a Cdk4R24Cbackground.  Treatment of Tyr-HRas:Cdk4R24C/R24C mice with the carcinogen, DMBA/TPA resulted in a further increase in the number of nevi and melanomas developed when compared with Tyr-HRas:Cdk4+/+ mice.  In summary, in Tyr-HRas:Cdk4R24C/R24Cmice, we observed that activated CDK4 cooperates with the oncogenic HRAS(G12V)protein to increase the susceptibility of melanoma development in vivo.

Cyclin dependent kinase 4 (Cdk4) is a cell cycle regulator involved in early G1 cell cycle progression and has been indirectly implicated in angiogenesis in the Min mouse system, a mouse that harbors a mutation in the Apc gene. Apc+/Minmice when crossed with Ink4a/arf-/-mice, exhibited increased angiogenesis of colorectal tumors suggesting that dysregulation of Cdk4 (due to loss of Ink4a-mediated suppression) may contribute to enhanced angiogenesis. To demonstrate a direct role for Cdk4 in angiogenesis, we crossed mice that have an activated Cdk4, Cdk4R24C/R24Cmice, with Apc+/Minmice and examined levels of angiogenesis in intestinal tumors formed. Our results show an increase in the percentage of highly vascularized tumors in Cdk4R24C/R24C:ApcMin/+and Cdk4+/R24C:ApcMin/+mice compared to Cdk4+/+:ApcMin/+mice. In addition immunohistochemical analysis showed an increase in CD-31 staining localized to endothelial cells of Cdk4R24C/R24C:ApcMin/+mouse tumors, supporting the hypothesis of increased vasculature in these tumors. Further analysis showed an increase in the expression of the E2F1 target proteins Vegf-b and Cyclin A in Cdk4R24C/R24C:Apc+/Min intestinal tumors. Together these data suggest that the dysregulated Cdk4 gene plays an important role in angiogenesis during intestinal tumor formation and may in part act via increasing E2F1 target proteins. This is the first report to show that Cdk4 has a direct role in angiogenesis in vivo and may be an important drug target to reduce or prevent angiogenesis during intestinal tumor formation.

Here we report the discovery of ON044580, an a-benzoyl styryl benzyl sulfide that possesses potent inhibitory activity against two unrelated kinases, JAK2 and BCR-ABL, and exhibits cytotoxicity to human tumor cells derived from chronic myelogenous leukemia (CML) and myelodysplasia (MDS) patients or cells harboring a mutant JAK2 kinase. This novel spectrum of activity is explained by the non–ATP-competitive inhibition of JAK2 and BCR-ABL kinases. ON044580 inhibits mutant JAK2 kinase and the proliferation of JAK2V617F-positive leukemic cells and blocks the IL-3–mediated phosphorylation of JAK2 and STAT5. Interestingly, this compound also directly inhibits the kinase activity of both wild-type and imatinib-resistant (T315I) forms of the BCR-ABL kinase. Finally, ON044580 effectively induces apoptosis of imatinib-resistant CML patient cells. The apparently unrelated JAK2 and BCR-ABL kinases share a common substrate, STAT5, and such substrate competitive inhibitors represent an alternative therapeutic strategy for development of new inhibitors. The novel mechanism of kinase inhibition exhibited by ON044580 renders it effective against mutant forms of kinases such as the BCR-ABLT315Iand JAK2V617F. Importantly, ON044580 selectively reduces the number of aneuploid cells in primary bone marrow samples from monosomy 7 MDS patients, suggesting another regulatory cascade amenable to this agent in these aberrant cells. Data presented suggest that this compound could have multiple therapeutic applications including monosomy 7 MDS, imatinib-resistant CML, and myeloproliferative neoplasms that develop resistance to ATP-competitive agents.

Background:Myelodysplastic syndrome (MDS) is a clinically heterogenous disease of hematopoietic stem cells (HSC) characterized by ineffective hematopoiesis, uni/multi-lineage dysplasia and a high tendency to transform into acute myeloid leukemia. Aberrant chromosomal and genetic lesions contribute to MDS pathogenesis which has been associated with chronic activation of the innate immune response and a hyperinflammatory microenvironment (Barryero L, et al.Blood, 2018). Dysfunction of Toll like receptors (TLR) and downstream effectors has been associated with the loss of progenitor function and differentiation of bone marrow (BM) cells in MDS patients. Azacitidine (AZA), a hypomethylating agent (HMA), is the mainstay of therapy for patients with higher-risk MDS (Silverman LR, The Myelodysplastic Syndrome in Cancer Medicine, Editors: R.J. Bast, et al. 2017) and carries an overall response rate (ORR) of 50% in patients with significant effects on hematopoiesis, ranging from improvement in a single lineage to complete restoration of blood counts and transfusion independence with survival benefits (Silverman LR, et al., Leukemia, 1993). The response to AZA is not durable and all patients relapse with worsening bone marrow failure.

“Gellan Gum”, widely used in food and confectionary industry as a thickening and gelling agent, has been employed as a reducing and stabilizing agent for the synthesis of gold nanoparticles. These nanoparticles display greater stability to electrolyte addition and pH changes relative to the traditional citrate and borohydride reduced nanoparticles. Subsequently these have been used to load anthracycline ring antibiotic doxorubicin hydrochloride. The drug loaded on these nanoparticles showed enhanced cytotoxic effects on human glioma cell lines LN‐18 and LN‐229.

A new method for the processing of textured YBa2Cu3Oy(Y 123) thick film stripes on metallic tapes is discussed. The process involves the texturing of Y123 grains by a localized directional solidification method by creating constitutional gradients along the width of the precursor Y2BaCuO5(Y 211) stripe during an infiltration and growthprocess. The differences in the solidification temperatures of different rare earth 123 compounds were utilized to generate the constitutional gradients. The sample configuration involves printed lines of light (Nd) and heavy (Yb) rare earth compounds on either side of an airbrushed Y211 stripe underneath a liquid phase (barium cuprates) layer. The higher peritectic temperature (Tp) Nd regions serve as nucleating sites for Y123 grains nucleated in the adjacent Y211 stripes and the constitutional gradients produced due to the diffusion of respective rare earth ions between the Nd and Yb regions, typically of 200 K cm?1in the region, induce a driving force for the directional growth of the nucleated grains. The solidification is analogous to that in a typical Bridgman furnace in applied high temperature gradients. The process, being independent of growth rate parameter and texture of the underlying substrate, is suitable for the fabrication of long length thick film conductors by a wind and react process in simple box type furnaces.

The effect of nano-size ZrO₂ powder addition on the microstructure and superconducting properties of Y–Ba–Cu–O single grain bulk superconductors has been investigated. Significant pushing phenomena of Y₂BaCuO₅ (Y-211) particles, particularly in the c growth sector, were observed even with a small amount of ZrO₂ added to the precursor powder. An increase in Y-211 particle pushing was observed with increasing ZrO₂ content, leading to an inhomogeneous bulk microstructure. In addition, a growth cycle consisting of a Y-211 free layer–porous narrow layer–Y-211 high concentration layer was observed for samples prepared with 0.25 wt% ZrO₂ in both the a and c growth sectors. The extent of the growth of single grain Y–Ba–Cu–O (YBCO) decreased with increasing ZrO₂ content due to increased pushing of Y-211 particles towards molten liquid. The superconducting transition temperature, T_c, of the ZrO₂ containing YBCO samples was sharp but depressed slightly (by up to 1 K) compared with an undoped YBCO grain, indicating a relative insensitivity of T_c to ZrO₂ content. Finally, the sensitivity of critical current density, J_c, to applied magnetic field in large grain bulk YBCO containing ZrO₂ was observed to depend critically on position due to the inhomogeneous sample microstructure.

The effect of nano-size ZrO2 powder addition on the microstructure and superconducting properties of Y–Ba–Cu–O single grain bulk superconductors has been investigated. Significant pushing phenomena of Y2BaCuO5 (Y-211) particles, particularly in the c growth sector, were observed even with a small amount of ZrO2 added to the precursor powder. An increase in Y-211 particle pushing was observed with increasing ZrO2 content, leading to an inhomogeneous bulk microstructure. In addition, a growth cycle consisting of a Y-211 free layer–porous narrow layer–Y-211 high concentration layer was observed for samples prepared with 0.25 wt% ZrO2 in both the a and c growth sectors. The extent of the growth of single grain Y–Ba–Cu–O (YBCO) decreased with increasing ZrO2 content due to increased pushing of Y-211 particles towards molten liquid. The superconducting transition temperature, Tc, of the ZrO2 containing YBCO samples was sharp but depressed slightly (by up to 1 K) compared with an undoped YBCO grain, indicating a relative insensitivity of Tc to ZrO2 content. Finally, the sensitivity of critical current density, Jc, to applied magnetic field in large grain bulk YBCO containing ZrO2 was observed to depend critically on position due to the inhomogeneous sample microstructure.

The effect of nano-size ZrO2powder addition on the microstructure and superconducting properties of Y-Ba-Cu-O single grain bulk superconductors has been investigated. Significant pushing phenomena of Y2BaCuO5(Y-211) particles, particularly in the cgrowth sector, were observed even with a small amount of ZrO2added to the precursor powder. An increase in Y-211 particle pushing was observed with increasing ZrO2content, leading to an inhomogeneous bulk microstructure. In addition, a growth cycle consisting of a Y-211 free layer-porous narrow layer-Y-211 high concentration layer was observed for samples prepared with 0.25 wt% ZrO2in both the aand cgrowth sectors. The extent of the growth of single grain Y-Ba-Cu-O (YBCO) decreased with increasing ZrO2content due to increased pushing of Y-211 particles towards molten liquid. The superconducting transition temperature, Tc, of the ZrO2containing YBCO samples was sharp but depressed slightly (by up to 1 K) compared with an undoped YBCO grain, indicating a relative insensitivity of Tcto ZrO2content. Finally, the sensitivity of critical current density, Jc, to applied magnetic field in large grain bulk YBCO containing ZrO2was observed to depend critically on position due to the inhomogeneous sample microstructure.

Porous superconductors have inherent cooling advantages over their bulk counterparts and, as a result, are emerging as an important class of materials for practical applications. Single-domain Y-Ba-Cu-O (YBCO) foams processed with a pre-defined, open porous structure, for example, have significant potential for use as elements in resistive superconducting fault current limiters. In this case, the interconnected porosity is ideal for producing reinforced composites with improved mechanical and heat conducting properties. In this paper we describe a few simple methods for fabricating large grain YBCO superconductors with various predefined porous structures via an infiltration process from tailored, porous Y2BaCuO5(Y-211) pre-forms manufactured by a variety of techniques, including slurry-coating of standard polyurethane foams to replicate their structure. Foams produced by this method typically have a strut thickness of a few hundred µm and pore sizes ranging from 10 to 100 pores per inch (PPI). Foams with increased strut thickness of up to millimetre dimensions can be produced by embedding organic ball spacers within the Y-211 pre-form followed by a burn-out and sintering process. Single-domain YBCO bulk materials with cellular and pre-defined 3D interconnected porosity may be produced by a similar process using tailored wax structures in Y-211 castings.