Mechanistic in situ and ex situ studies of phase transformations in molecular co-crystals

Co‐crystallisation is widely explored as a route to improve the physical properties of pharmaceutical active ingredients, but little is known about the fundamental mechanisms of the process. Herein, we apply a hyphenated differential scanning calorimetry—X‐ray diffraction technique to mimic the commercial hot melt extrusion process, and explore the heat‐induced synthesis of a series of new co‐crystals containing isonicotinamide. These comprise a 1:1 co‐crystal with 4‐hydroxybenzoic acid, 2:1 and 1:2 systems with 4‐hydroxyphenylacetic acid and a 1:1 crystal with 3,4‐dihydroxyphenylactic acid. The formation of co‐crystals during heating is complex mechanistically. In addition to co‐crystallisation, conversions between polymorphs of the co‐former starting materials and co‐crystal products are also observed. A subsequent study exploring the use of inkjet printing and milling to generate co‐crystals revealed that the synthetic approach has a major effect on the co‐crystal species and polymorphs produced

Quantum trajectory approach to stochastically-induced quantum interference effects in coherently-driven two-level atoms

Stochastic perturbation of two-level atoms strongly driven by a coherent light field is analyzed by the quantum trajectory method. A new method is developed for calculating the resonance fluorescence spectra from numerical simulations. It is shown that in the case of dominant incoherent perturbation, the stochastic noise can unexpectedly create phase correlation between the neighboring atomic dressed states. This phase correlation is responsible for quantum interference between the related transitions resulting in anomalous modifications of the resonance fluorescence spectra.Comment: paper accepted for publicatio

Petrografia, geoquímica e geocronologia dos granitos patrimônio Santo Antônio e São Domingos (Suíte Cunhaporanga, Paraná, Sudeste do Brasil)

The Patrimônio Santo Antônio and São Domingos Granites are located in the northwest portion of the Itaiacoca Belt, which is part of the Apiaí Terrane (or tectonic domain), a segment of the southern Ribeira Belt, the major tectonic unit of the Mantiqueira Province (Southeast Brazil). These granites are related to the Cunhaporanga Granitic Suite and are intrusive into metasedimentary rocks of the Itaiacoca Group. The plutons are represented mainly by porphyritic monzogranites, with rare occurrences of syenogranites. The porphyritic monzogranites are ferroan to magnesian, high-K, alkali-calcic, and metaluminous to peraluminous. Trace elements patterns of the granites, which have been locally affected by hydrothermal alteration, suggest an association with magmas emplaced in a late- to post-tectonic setting. The geochemical signatures suggest a mantle source enriched in incompatible elements remobilized from the oceanic crust during subduction. The geochronological age of the Patrimônio Santo Antônio Granite (589 ± 6 Ma, zircon, U-Pb SHRIMP) indicates that the magmatism associated with these plutons occurred between the final stages of evolution of the Cunhaporanga Granitic Suite (ca. 650 to 590 Ma) and the emplacement of the post-orogenic and anorogenic plutons of the Apiaí Domain (ca. 590 to 570 Ma).Os Granitos Patrimônio Santo Antônio e São Domingos localizam-se na porção noroeste da Faixa Itaiacoca constituinte do Terreno (ou domínio tectônico) Apiaí segmento do Cinturão Ribeira Meridional da Província Mantiqueira localizada no sudoeste do Brasil. Ambos estão relacionados com a Suíte Granítica Cunhaporanga e são intrusivos em rochas metassedimentares do Grupo Itaiacoca. São constituídos por ocorrências esparsas de sienogranitos e majoritariamente por monzogranitos porfiríticos de caráter metaluminoso a peraluminoso, álcali-cálcico de alto K e comportamento ferroso a magnesiano. O comportamento dos elementos traços, por vezes afetado por alteração hidrotermal, é sugestivo de magmatismo pós a tardi-colisional, com assinaturas geoquímicas que sugerem origem a partir de manto enriquecido pela adição de elementos incompatíveis remobilizados de crosta oceânica durante subducção. A idade geocronológica obtida para o Granito Patrimônio Santo Antônio (589 ± 6 Ma, zircões, U-Pb, SHRIMP) situa o magmatismo destes plútons entre os estágios finais de evolução da Suíte Granítica Cunhaporanga (ca. 650 a 590 Ma) e da colocação dos plútons pós-orogênicos e anorogênicos do Domínio Apiaí (ca. 590 a 570 Ma)

Nitrate transport in Chalk catchments : monitoring, modelling and policy implications

Rising nitrate levels have been observed in UK Chalk catchments in recent decades, with concentrations now approaching or exceeding legislated maximum values in many areas. In response, strategies seeking to contain concentrations through appropriate land management are now in place. However, there is an increasing consensus that Chalk systems, a predominant landscape type over England and indeed northwest Europe, can retard decades of prior nitrate loading within their deep unsaturated zones. Current levels may not fully reflect the long-term impact of present-day practices, and stringent land management controls may not be enough to avert further medium-term rises. This paper discusses these issues in the context of the EU Water Framework Directive, drawing on data from recent experimental work and a new model (INCA-Chalk) that allows the impacts of different land use management practices to be explored. Results strongly imply that timelines for water quality improvement demanded by the Water Framework directive are not realistic for the Chalk, and give an indication of time-scales over which improvements might be achieved. However, important unresolved scientific issues remain, and further monitoring and targeted data collection is recommended to reduce prediction uncertainties and allow cost effective strategies for mitigation to be designed and implemented

Fault rock lithologies and architecture of the central Alpine fault, New Zealand, revealed by DFDP-1 drilling

The first phase of the Deep Fault Drilling Project (DFDP-1) yielded a continuous lithological transect through fault rock surrounding the Alpine fault (South Island, New Zealand). This allowed micrometer- to decimeter-scale variations in fault rock lithology and structure to be delineated on either side of two principal slip zones intersected by DFDP-1A and DFDP-1B. Here, we provide a comprehensive analysis of fault rock lithologies within 70 m of the Alpine fault based on analysis of hand specimens and detailed petrographic and petrologic analysis. The sequence of fault rock lithologies is consistent with that inferred previously from outcrop observations, but the continuous section afforded by DFDP-1 permits new insight into the spatial and genetic relationships between different lithologies and structures. We identify principal slip zone gouge, and cataclasite-series rocks, formed by multiple increments of shear deformation at up to coseismic slip rates. A 20−30-m-thick package of these rocks (including the principal slip zone) forms the fault core, which has accommodated most of the brittle shear displacement. This deformation has overprinted ultramylonites deformed mostly by grain-size-insensitive dislocation creep. Outside the fault core, ultramylonites contain low-displacement brittle fractures that are part of the fault damage zone. Fault rocks presently found in the hanging wall of the Alpine fault are inferred to have been derived from protoliths on both sides of the present-day principal slip zone, specifically the hanging-wall Alpine Schist and footwall Greenland Group. This implies that, at seismogenic depths, the Alpine fault is either a single zone of focused brittle shear that moves laterally over time, or it consists of multiple strands. Ultramylonites, cataclasites, and fault gouge represent distinct zones into which deformation has localized, but within the brittle regime, particularly, it is not clear whether this localization accompanies reductions in pressure and temperature during exhumation or whether it occurs throughout the seismogenic regime. These two contrasting possibilities should be a focus of future studies of fault zone architecture

Petrography, Geochemistry and Geochronology of the Patrimônio Santo Antônio and São Domingos Granites (Cunhaporanga Granitic Suite, Paraná, Southeast Brazil)

The Patrimônio Santo Antônio and São Domingos Granites are located in the northwest portion of the Itaiacoca Belt,which is part of the Apiaí Terrane (or tectonic domain), a segment of the southern Ribeira Belt, the major tectonic unit of theMantiqueira Province (Southeast Brazil). These granites are related to the Cunhaporanga Granitic Suite and are intrusive intometasedimentary rocks of the Itaiacoca Group. The plutons are represented mainly by porphyritic monzogranites, with rareoccurrences of syenogranites. The porphyritic monzogranites are ferroan to magnesian, high-K, alkali-calcic, and metaluminousto peraluminous. Trace elements patterns of the granites, which have been locally affected by hydrothermal alteration, suggestan association with magmas emplaced in a late- to post-tectonic setting. The geochemical signatures suggest a mantle sourceenriched in incompatible elements remobilized from the oceanic crust during subduction. The geochronological age of thePatrimônio Santo Antônio Granite (589 ± 6 Ma, zircon, U-Pb SHRIMP) indicates that the magmatism associated with theseplutons occurred between the fi nal stages of evolution of the Cunhaporanga Granitic Suite (ca. 650 to 590 Ma) and theemplacement of the post-orogenic and anorogenic plutons of the Apiaí Domain (ca. 590 to 570 Ma)