In-situ δ18O and 87Sr/86Sr proxies in an unconformable clastic unit at the Ordovician-Silurian transition.

Clastic successions found in the carbonate platform of continental margin during the Ordovician-Silurian Transition (OST) period are archives for interpreting paleo-depositional systems. Here, we report in-situ δ18Oquartz and 87Sr/86Srcarbonate isotope chemo-stratigraphy for an unconformable clastic unit from the Cathaysia terrane that rifted off the Gondwana Supercontinent in the Early Paleozoic Era. Our results suggest a depositional proxy and model for geological events attributed to rapid changes in the sedimentary environment during the OST period. Importantly, these results present crucial clues that infer the influence of Paleo-Tethys Sea opening, global eustatic regression, and rapid sedimentary provenance change. Our study provides insight into paleo-tracer that could be a key method for interpreting depositional system of carbonate platform based on in-situ mineral isotope chemo-stratigraphy that preserves the original value of provenance and geochemical condition.

Eclogite resembling metamorphic disequilibrium assemblage formed through fluid-induced metasomatic reactions.

Equilibrium omphacite-garnet-bearing mafic rocks have been classified as eclogites, either pristine or retrogressed, that were formed at great depths in the lithosphere. Here we report a unique natural example of eclogite resembling assemblage in disequilibrium formed through fluid-induced metasomatic reactions under the amphibolite to granulite facies. Primarily, the amphibolized protolith experienced a garnet-amphibolite facies metamorphism at ~ 500-700 °C and ~ 0.8-1 GPa. Subsequently, CO2 fluid induced fracturing and dissolution-reprecipitation reactions occurred at peak metamorphic conditions of ~ 700 °C and ~ 1 GPa. Occasional omphacite-albite assemblage, which gradually replace diopside-oligoclase symplectite adjacent to albite veins along fractures, indicates fluid-induced coupled dissolution-reprecipitation disequilibrium reactions. Here the albite-omphacite assemblage is in local equilibrium at least on 1 mm length scale, during cooling, below ~ 600 ºC and ~ 1 GPa, within the amphibolite facies conditions. The results from this study clearly suggest that disequilibrium garnet-omphacite assemblage in mafic rocks could be formed by crustal reworking processes below granulite facies conditions, and their textural equilibrium is an important criterion while defining eclogite facies.

Gentamicin-intercalated smectite as a new therapeutic option for Helicobacter pylori eradication.

Objectives: Novel antibacterial strategies against Helicobacter pylori are needed because H. pylori strains are acquiring resistance to antibiotics. We evaluated the efficacy of gentamicin-intercalated smectite hybrid (S-GEN)-based treatment regimens in a murine model of H. pylori infection. Methods: Two groups of 10 rats were administered either smectite or S-GEN to measure coverage of the gastric mucosa. To evaluate anti-H. pylori efficacy, mice were divided into eight groups of 10 mice each given different treatments, and H. pylori eradication was assessed by a Campylobacter-like organism (CLO) test and H. pylori PCR of the gastric mucosa, and H. pylori antigen and H. pylori PCR analysis of mouse faeces. The levels of proinflammatory cytokines were examined. Results: S-GEN was retained in the gastric mucosal layer with a >60% distribution ratio for up to 1 h, and the S-GEN-based triple regimen decreased bacterial burden in vivo compared with that of untreated mice or mice treated with other regimens. The cure rates in the CLO test and H. pylori PCR from gastric mucosa were 70%, 60%, 80%, 50%, 60% and 60% in Groups III-VIII, respectively. Those for H. pylori PCR in the faeces of mice were 90% and 100% in Group III with standard therapy and Group V with triple therapy including S-GEN, respectively. S-GEN triple therapy also reduced the levels of proinflammatory cytokines. Conclusions: These results suggest that S-GEN is a promising and effective therapeutic agent for the treatment of H. pylori infection.

Effects of Aging on Transformation of Biogenic Magnetite Nanoparticles.

This study examined the microbial synthesis of magnetite and Pd/Zn-substituted magnetite using metal-reducing bacteria (Clostridium sp.), and the mineralogical characteristics of various types of magnetite formed initially and transformed minerals aged for 5 years. XRD, SXRD, and TEM-EDS analyses were used to characterize the mineralogy, crystal structure, chemistry, shape, and size distribution of the magnetites and transformed minerals. The metal-reducing bacteria reduced akaganeite and Pd/Zn-akaganeite to magnetite and Pd/Zn-substituted magnetite using glucose as an electron donor, respectively. Metal substitution of Pd and Zn within the magnetite structure resulted in a decrease in the unit-cell parameter of the magnetite crystals. After 5 years, the biogenic magnetite showed changes in unit-cell parameters and transformation to siderite during prolonged cultivation under anaerobic conditions. These results indicate that long-term aging may affect the mineralogical transformation and alter the nano-sized crystal structure.

Effective utilization of incinerated municipal solid waste incineration ash: zeolitic material synthesis and silica extraction.

In this study the effective utilization of two types of municipal solid waste incinerator (MSWI) ashes, namely air-cooled ash (ACS) and water-cooled ash (WCS) samples obtained from a municipal solid waste incineration plant, was examined by applying zeolitic material synthesis and silica extraction. The influence of the experimental conditions including the ratio of sample : NaOH solution, the reaction temperature and time, and the concentration of NaOH solution were investigated. The results for the 25 experimental trials can be summarized as: (1) the formation of tobermorite and/or pectolite-1A as a major component in most conditions; (2) the synthesis of hydroxycancrinite as a major phase at 200 degrees C; (3) a dramatic increase in the extracted SiO(2) yield at 1 : 30 value of sample : NaOH ratio and 200 degrees C, even at short reaction times; and (4) relatively high SiO(2) yields for WCS ashes rather than ACS ashes. An increase in the reaction time improved the quantity of synthesized zeolitic materials. The reaction temperature determined the type of zeolite. An increase in the NaOH concentration can be an essential factor to improve zeolitic material synthesis, but it significantly reduced the yield of SiO(2) extraction. In conclusion, suitable conditions for obtaining both SiO(2) extraction and synthesized zeolites from the ashes of the incinerated solid waste materials should be: 200 degrees C reaction temperature; a 1 : 30 (g : mL) value for the sample : NaOH ratio; 2 mol L(-1) NaOH concentration; and a reaction time of more than 24 h.

Single-walled hollow nanospheres assembled from the aluminogermanate precursors.

Ordered single-walled hollow aluminogermanate (ALGE) nanospheres (NSs) with average monodisperse diameters of 5 nm have been synthesized for the first time using simple pH control. This involved basification of the ALGE precursors (having an Al/Ge ratio of 1.33) to a pH value of 13, followed by immediate acidification to a pH value of 9.