Magmas containing the components needed to form porphyry copper deposits are relatively common within arcs, yet mineralising events are uncommon within the long-lived magmatic systems that host them. ...Understanding what causes the transition from barren to productive intrusions is critical to the development of conceptual deposit models. We have constrained the tempo of pre- and syn-mineralisation magmatic events in relationship to the thermal evolution of the plutonic body that underlies one of the world's youngest exposed plutonic–porphyry systems, the Inamumu Zoned Pluton, Koloula Porphyry Prospect, Solomon Islands. High precision ID-TIMS U–Pb dates of texturally and chemically characterised zircons indicate pluton emplacement over <150 kyr was superseded after ca. 50 kyr by two discrete episodes of mineralising porphyritic melt emplacement. Their associated hydrothermal systems initiated within ca. 30 kyrs of each other. Zircon populations within evolved intrusions contain resorbed cores that were recycled from the deeper magmatic system, yet their youngest dates are statistically indistinguishable from those yielded by crystals lacking resorption. Comparisons of Ti-in-zircon proxy temperatures, modelled zircon saturation temperatures and temperature–crystallinity relationships suggest that prior to being heated and emplaced within the shallow level pluton, magmas were stored at depth in a high-crystallinity (>50% crystals) state, past the point of rheological lock-up. We estimate that thermal rejuvenation of the deeper high-crystallinity magma and generation of a mobile melt fraction may have occurred ≤10 kyr before its transport and emplacement within the porphyry environment. The underlying pluton likely cooled and returned to high-crystallinity states prior to subsequent remobilisation-emplacement events. Titanium-in-zircon geothermometry and whole-rock geochemistry suggest pre-mineralisation intrusions were remobilised by mixing of a silicic magma with a high-temperature, less-evolved melt. In contrast, syn-mineralisation melts were most likely remobilised by the percolation of hot volatiles exsolved from contemporaneous less-evolved intrusions cooling beneath the crystalline silicic magma. The evidence for the rapid thermal rejuvenation and long term storage of highly crystalline silicic magmas is consistent with previous studies that indicate two components of exsolved volatiles contribute to ore forming fluids. We conclude that the liberation of crystal-rich porphyry copper deposit forming magmas, and the addition of the chemical components required for ore formation, are intrinsically linked to the volatiles released during the recharge of less-evolved melt into a highly crystalline silicic magma.
•Characterised and dated zircons from one of the world's youngest porphyry systems.•Two consecutive and discrete mineralising hydrothermal systems within ca. 30 kyr.•Precursor magma stored in low-temperature, >50% crystals, immobile state at depth.•Brief thermal rejuvenation–remobilisation of magma preceded porphyry emplacement.•Thermal recharge from volatiles, not extensive hybridisation, favours mineralisation.
Savo, Solomon Islands, is a historically active volcano dominated by sodic, alkaline lavas, and pyroclastic rocks with up to 7.5 wt% Na
2
O, and high Sr, arc-like trace element chemistry. The suite ...is dominated by mugearites (plagioclase–clinopyroxene–magnetite ± amphibole ± olivine) and trachytes (plagioclase–amphibole–magnetite ± biotite). The presence of hydrous minerals (amphibole, biotite) indicates relatively wet magmas. In such melts, plagioclase is relatively unstable relative to iron oxides and ferromagnesian silicates; it is the latter minerals (particularly hornblende) that dominate cumulate nodules at Savo and drive the chemical differentiation of the suite, with a limited role for plagioclase. This is potentially occurring in a crustal “hot zone”, with major chemical differentiation occurring at depth. Batches of magma ascend periodically, where they are subject to decompression, water saturation and further cooling, resulting in closed-system crystallisation of plagioclase, and ultimately the production of sodic, crystal and feldspar-rich, high-Sr rocks. The sodic and hydrous nature of the parental magmas is interpreted to be the result of partial melting of metasomatised mantle, but radiogenic isotope data (Pb, Sr, Nd) cannot uniquely identify the source of the metasomatic agent.
The adsorption affinity of a surfactant foaming agent (SFA), α-olefin sulphonate (AOS)—used for generation of foam for low density concrete—to organically-modified montmorillonite (OMMT) has been ...investigated. OMMT has been proposed as an additive to cement and concrete for improved strength and durability. Similar thermodynamic processes are involved in the generation and stabilisation of foam and in the compatibilisation and stabilisation of organic particles in aqueous environments, so interaction between SFA and OMMT particles is likely. Association of foaming agent molecules with organoclay may lead to poor foaming performance and potential instability of the nanoparticles due to displacement of dispersants from the particle surface by foaming agent. Adsorption isotherms determined using a combination of ion-pair reverse phase high performance liquid chromatography (RP-HPLC) and gravimetric methods revealed that there is a relatively high affinity of AOS for the organoclay particles. This is a dynamic process, with smaller molecules adsorbing quickly but being displaced by larger molecules at higher surfactant loading. From the adsorption isotherm it was possible to calculate the minimum AOS addition that will ensure the full foaming performance in the cement formulation. Relative adsorption affinity and competitive adsorption at the particle surface of AOS with non-ionic and anionic surfactants commonly used as wetting and dispersing agents, was studied. The dispersants displayed considerably higher relative adsorption onto the organoclay than AOS, particularly in the case of the anionic species. There is evidence that some AOS adsorption takes place in particle systems stabilised by non-ionic dispersants; displacement of high adsorption affinity dispersants by the lower affinity AOS from the OMMT particle surface was not observed.
Immunodeficient mouse models are helping to advance the field of oncology. A new model on the market, the B6;129-Rag2tm1FwaIL2rgtm1Rsky/DwlHsd (R2G2) knockout mouse, lacks responsiveness to common ...gamma chain cytokines, including IL-2, IL-4, IL-7, IL-9 and IL-15. In addition, this model exhibits defects in lymphoid development and so lacks mature lymphocytes of the B, T, and natural killer (NK) cell lineages. Herein we describe growth of multiple patient-derived (PDX) and tumour cell line xeno- (CDX) and allo-grafts in the R2G2 immunodeficient mouse model.
The PDXs examined include colorectal and head and neck cancers. The CDXs studied include esophageal (OE33 and FLO1) and stomach cancer (AGS). Tumour growth data was also collected from two allografts of murine colorectal cancer (CT26) and B-cell lymphoma (A20) cells.
Colorectal PDX tissue was comparable between the R2G2 and the NSG mouse models, however the standard error was much lower in the R2G2 strain. Head and neck PDX 626 and 635 was transplanted in into 4 sections of R2G2 mice each, and 100% of mice developed either one or two tumours. The human esophageal adenocarcinoma OE33 cells were implanted into both flanks of R2G2, Athymic Nude and SCID mice. There was a 100% take rate in R2G2 mice, 0% in SCID mice and 17% in Athymic Nude mice. The human esophageal adenocarcinoma FLO1 cells were examined in two studies. In both studies, cells were injected into both flanks of R2G2 and SCID mice. Study A also examined growth in Athymic Nude mice. In study A, no tumour growth was seen in Athymic Nude or SCID mice, whereas the take rate was 100% in R2G2 mice. In study B, the take rate was 100% in both the R2G2 and the SCID mice, although differences were seen in growth rate. Human gastric adenocarcinoma AGS cells were implanted in both flanks of R2G2 and SCID mice. The take rate was 75% in R2G2 mice and 0% in SCID mice. Head and neck squamous cell carcinoma SQ20b cells were implanted in R2G2 mice and take rate was 90%. Growth of two allogeneic tumour lines was also examined. The mouse colon carcinoma CT26 cells were implanted in R2G2 mice and took in 100% of the mice. Mouse B-cell lymphoma A20 cells were implanted in R2G2 mice and take rate was 100%. Both allografts grew to 1000mm3 by 13 days post implantation.
These data provide evidence that the R2G2 mouse model is a valuable tool for oncology programs including cell line tumour models research, with high take rates and quick growth of allogeneic models.
The B6;129-Rag2tm1FwaIL2rgtm1Rsky/DwlHsd (R2G2) knockout mouse was developed by backcrossing an IL2rg (common gamma) knockout model to a RAG2 (recombinase activating gene) knockout model. The ...resulting mouse lacks various cytokines including IL-2, IL-4, IL-7, IL-9 and IL-15. In addition, this model lacks B cells, T cells, NK cells and has a deficit in lymphocyte development. This model was developed to provide another immunodeficient option for the oncology and immunology fields. The literature supports better tolerability of DNA damaging oncology treatments for models that do not carry the SCID mutation. We have already reported in a white paper that the R2G2 mouse model is more tolerant of whole body radiation than a model with the SCID mutation. Herein we describe a study examining chemotherapeutic tolerability of common DNA damaging oncology drugs including 5-fluorouracil (5-FU), doxorubicin (Doxo), and cyclophosphamide (CTX) (n=10 per group).
5-FU was given at 30, 60 or 100 mg/kg, intraperitoneally, twice weekly for five weeks. Doxo was given at 2 or 5 mg/kg, intraperitoneally, once weekly for three weeks. CTX was given at 100 or 140 mg/kg intraperitoneally, once weekly for three weeks. The low dose was chosen based on the average dose used in immunodeficient mouse models and the high dose was chosen based on the average dose used in immunocompetent mouse models. This was done to determine if the R2G2 mouse model can tolerate higher doses of these chemotherapeutic agents compared to other immunodeficient mouse models.
Results show that the R2G2 mouse model tolerates higher doses of these chemotherapeutic drugs than doses found in the literature for SCID models. Exogenous oestrogen tolerance is another common concern in oncology research as some immunodeficient mouse models cannot tolerate the subcutaneous oestrogen pellets, developing negative secondary effects resulting in removal from study. We performed an oestrogen pellet dose response study using four doses of 60 day release 17-β estradiol pellets at 0.18, 0.36, 0.72, and 1.7 mg/pellet (n=10 per group). R2G2 mice show dose dependent effects of oestrogen on morbidity. These data will allow researchers to determine the optimal dose for use in the R2G2 model.
In conclusion, these data support that the R2G2 mouse model may be a good alternative to SCID models when administering DNA damaging chemotherapies or when oestrogen supplementation is required for xenograft growth.
The Golden Age of American Musical Theatre: 1943-1965 provides synopses, cast and production credits, song titles, and other pertinent information for over 180 musicals from Oklahoma! to On A Clear ...Day You Can See Forever. Concentrating on a 22-year span, this book lists both commercial successes and flops of the Golden Age-when the musicals presented on Broadway showcased timeless, memorable tunes, sophisticated comedy, and the genius of creative artists like Richard Rodgers, Oscar Hammerstein, Jerome Robbins, Leonard Bernstein, George Abbott, Moss Hart, Angela Lansbury, Robert Preston, and many others. After an introduction and an overview of the history of Broadway, Naden offers a chronological timeline of the Golden Age musicals in America. She then presents details, in succeeding chapters, about the shows, the stars (on and off stage), the theatres, and the awards, beginning with an alphabetical listing of shows. Each show entry supplies the title, opening date, theatre, number of performances, primary cast and crew, and a plot synopsis, as well as other interesting data about the show, such as the awards won. Additional details about well-known actors, singers, composers, lyricists, directors, and choreographers of the period are provided, including birth and death dates, birth cities, born names, a brief biography, and award nominations and wins. Finishing with a bibliography and an index, this book is beneficial to anyone wanting to know more about one of the richest periods in Broadway history.
Carbon dioxide capture and storage by mineralization has been proposed as a possible technology to contribute to the reduction of global CO2 levels. A main candidate as a feed material, to supply Mg ...cations for combination with CO2 to form carbonate, is the family of ultramafic rocks, Mg‐rich silicate rocks with a range of naturally occurring mineralogical compositions. A classification scheme is described and a diagram is proposed to display the full range of both fresh and altered ultramafic rock compositions. This is particularly for the benefit of technologists to raise the awareness of the variation in possible feedstock materials. A systematic set of acid leaching experiments, in the presence of recyclable ammonium bisulphate, has been carried out covering the range of ultramafic rock compositions. The results show that lizardite serpentinite releases the most Mg with 78% removed after 1 h, while an olivine rock (dunite) gave 55% and serpentinized peridotites intermediate values. Antigorite serpentinite only released 40% and pyroxene‐ and amphibole‐rich rocks only 25%, showing they are unsuitable for the acid leaching method used. This wide variation in rock compositions highlights the necessity for accurate mineralogical characterization of potential resources and for technologists to be aware of the impact of feed material variations on process efficiency and development.
PDF
