Development of a stability-indicating UPLC method for determination of isotretinoin in bulk drug

A highly sensitive and rapid stability indicating ultra-performance liquid chromatographic (UPLC) method was developed for the quantification and identification of isotretinoin in bulk. Chromatographic separation was developed using a gradient elution in a reversed-phase system at flow rate of 0.5 ml/min with 12 min run time. The mobile phase was a gradient mixture of mobile phase A (contained a 30:70:0.5 mixture solution of methanol/purified water/glacial acetic acid) and mobile phase B (contained a 70:25:4.5:0.5 mixture solution of methanol/acetonitrile/purified water/glacial acetic acid). Eluents were monitored at 355 nm. The analytical method was validated for accuracy, precision, robustness, linearity, and forced degradation in accordance with the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) topic Q2 (R1) ‘Validation of Analytical Procedures: Text and Methodology’. The method was linear over a concentration range of (1–7 µg/ml) with correlation coefficient of (r2 > 0.9999). The accuracy was confirmed by calculating the % recovery which was found to be 100.0–101.6%. The RSD values obtained for repeatability and intermediate precision experiments were less than 2%. The limit of detection (LOD) was 0.12 µg/ml, while the limit of quantification (LOQ) was 0.38 µg/ml. The drug samples were exposed to different stressed conditions and the results showed that all degradation products were satisfactorily separated from each other and from the peak of the drug using the developed method. The proposed method can be used for the quantitative determination of isotretinoin with confidence

Effect of a freeze on some technological characteristics of several sugar cane varieties

Em 18 de julho de 1975, ocorreu geada no Estado de São Paulo; em Piracicaba, a temperatura atingiu -1ºC. Aproveitou-se a ocorrência da geada para investigar seus efeitos sobre características tecnológicas de algumas variedades. Foram tomadas amostras de dez colmos cada uma, a partir de doze dias após a geada, e depois, aproximadamente, a cada duas semanas. Analisaram-se brix % caldo, pol % caldo e, por inferência, produção de açúcar provável (em kg/t de cana). Dadas as condições do meio ambiente e das próprias plantas, pode-se dizer que estas não sofreram alterações dignas de nota nas sete amostras quinzenais efetuadas após a geada, nas características analisadas. Aplicando-se análise de regressão, verificou-se que os dados de brix % caldo ajustaram-se melhor às curvas de 2º grau. O teste F para regressão foi significativo em nove dos quinze casos estudados.A freeze occurred in the State of São Paulo, on July, 18th, 1975 with the temperature decreasing to -1ºC in Piracicaba. Advantage was taken of this occurrence to study the effect of freeze on the technological characteristics of some commercial sugar cane varieties. Ten stalk samples were taken for the experiment, beginning at twelve days after the freeze and thereafter every two weeks. Brix % juice, pol % juice and, by inference, theoretical sugar yield (kg/t of cane) were studied. Due to the environmental and plant conditions in the field, it could be concluded that the varieties did not show significant alterations caused by the freeze in none of the seven fortnight samples. Regression analysis showed that brix % juice data fitted 2nd degree curves better than the other data, with F test significant in nine out of fifteen cases

Boundary layer recovery and precipitation symmetrization preceding rapid intensification of tropical cyclones under shear

This study investigates the precipitation symmetrization preceding rapid intensification (RI) of tropical cyclones (TCs) experiencing vertical wind shear by analyzing numerical simulations of Typhoon Mujigae (2015) with warm (CTL) and relatively cool (S1) sea surface temperatures (SSTs). A novel finding is that precipitation symmetrization is maintained by the continuous development of deep convection along the inward flank of a convective precipitation shield (CPS), especially in the downwind part. Beneath the CPS, downdrafts flush the boundary layer with low-entropy parcels. These low-entropy parcels do not necessarily weaken the TCs; instead, they are “recycled” in the TC circulation, gradually recovered by positive enthalpy fluxes, and develop into convection during their propagation toward a downshear convergence zone. Along-trajectory vertical momentum budget analyses reveal the predominant role of buoyancy acceleration in the convective development in both experiments. The boundary layer recovery is more efficient for warmer SST, and the stronger buoyancy acceleration accounts for the higher probability of these parcels developing into deep convection in the downwind part of the CPS, which helps maintain the precipitation symmetrization in CTL. In contrast, less efficient boundary layer recovery and less upshear deep convection hinder the precipitation symmetrization in S1. These findings highlight the key role of boundary layer recovery in regulating the precipitation symmetrization and upshear deep convection, which further accounts for an earlier RI onset timing of the CTL TC. The inward rebuilding pathway also illuminates why deep convection is preferentially located inside the radius of maximum wind of sheared TCs undergoing RI

Autonomous and Lagrangian ocean observations for Atlantic tropical cyclone studies and forecasts

Author Posting. © The Oceanography Society, 2017. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 30, no. 2 (2017): 92–103, doi:10.5670/oceanog.2017.227.The tropical Atlantic basin is one of seven global regions where tropical cyclones (TCs) commonly originate, intensify, and affect highly populated coastal areas. Under appropriate atmospheric conditions, TC intensification can be linked to upper-ocean properties. Errors in Atlantic TC intensification forecasts have not been significantly reduced during the last 25 years. The combined use of in situ and satellite observations, particularly of temperature and salinity ahead of TCs, has the potential to improve the representation of the ocean, more accurately initialize hurricane intensity forecast models, and identify areas where TCs may intensify. However, a sustained in situ ocean observing system in the tropical North Atlantic Ocean and Caribbean Sea dedicated to measuring subsurface temperature, salinity, and density fields in support of TC intensity studies and forecasts has yet to be designed and implemented. Autonomous and Lagrangian platforms and sensors offer cost-effective opportunities to accomplish this objective. Here, we highlight recent efforts to use autonomous platforms and sensors, including surface drifters, profiling floats, underwater gliders, and dropsondes, to better understand air-sea processes during high-wind events, particularly those geared toward improving hurricane intensity forecasts. Real-time data availability is key for assimilation into numerical weather forecast models.The NOAA/AOML component of this work was originally funded by the Disaster Relief Appropriations Act of 2013, also known as the Sandy Supplemental, and is currently funded through NOAA research grant NA14OAR4830103 by AOML and CARICOOS, as well as NOAA’s Integrated Ocean Observing System (IOOS). The TEMPESTS component of this work is supported by NOAA through the Cooperative Institute for the North Atlantic Region (NA13OAR4830233) with additional analysis support from the WHOI Summer Student Fellowship Program, Nortek Student Equipment Grant, and the Rutgers University Teledyne Webb Graduate Student Fellowship Program. The drifter component of this work is funded through NOAA grant NA15OAR4320071(11.432) in support of the Global Drifter Program

Actualistic taphonomic study of the rodents digested by the Achala culpeo fox (Lycalopex culpaeus smithersi) in the highlands of central Argentina

We present the first actualistic study of the rodents consumed by the South American foxLycalopex culpaeus smithersi (Achala culpeo fox), a subspecies of the culpeo fox that is endemicto the highlands of central Argentina. We provide a taphonomic characterization of this canidbased on digested micromammal bones, and compare it to other carnivores. We studied over 1000bones derived from 83 scats collected in Quebrada del Condorito National Park, Córdobaprovince, Argentina, corresponding to caviomorph and myomorph rodents. Galea leucoblepharawas the main prey (59.8% MNI, 93.1% biomass). Average relative abundance for the totalassemblage was 26.7. Cranial and, to a lesser extent, proximal limb bones were the most abundantelements. A high degree of breakage was observed in cranial elements and, to a lesser extent, inlimb bones. A high proportion of heavy and extreme digestion was inferred, while some elementsbear light or no digestion traces at all. Overall, the Achala culpeo fox fits best with othermammalian carnivores in the category of extreme modification, and shows types and proportionsof taphonomic attributes similar to other South American mammalian predators. These resultscontribute to the understanding of regional taphonomic processes and of digestivemodifications by Lycalopex foxes generally, and are thus relevant to interpreting the presence of micromammal remains in the archaeological and palaeontological recordsand the impact of these foxes in their formation.Fil: Coll, Daiana Geraldine. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Montalvo, Claudia Inés. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Fernández, Fernando Julián. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pia, Monica Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Mondini, Nora Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Antropología de Córdoba. Universidad Nacional de Córdoba. Facultad de Filosofía y Humanidades. Instituto de Antropología de Córdoba; Argentin

Evidence for early Pliocene and late Miocene transgressions in southern Patagonia (Argentina): 87Sr/86Sr ages of the pectinid “Chlamys” actinodes (Sowerby)

AbstractNumerical ages based on 87Sr/86Sr dating of calcitic shells belonging to the pectinid “Chlamys” actinodes (Sowerby) document the only late Miocene (Tortonian) sea flooding event in the Austral Basin at Cabo Buentiempo (8.95 ± 0.82 Ma, 2 s.e.), and provide evidence of the first documented early Pliocene (Zanclean) transgression in Argentina recorded at Cañadón Darwin (5.15 ± 0.18 Ma, 2 s.e., Austral Basin) and at Terraces of Cerro Laciar (5.10 ± 0.21 Ma, 2 s.e.), southern San Jorge Basin). The sedimentary rocks deposited during the Tortonian are correlated with the youngest beds deposited by the “Entrerriense Sea” that covered northern Patagonia. The Zanclean marine episode is correlated with the long-term cycle represented in the Southern Hemisphere by the flooding events recorded in Cockburn and James Ross Islands (Antarctica) and in North-Central Chile

Formation of the Isthmus of Panama

The formation of the Isthmus of Panama stands as one of the greatest natural events of the Cenozoic, driving profound biotic transformations on land and in the oceans. Some recent studies suggest that the Isthmus formed manymillions of years earlier than the widely recognized age of approximately 3 million years ago (Ma), a result that if true would revolutionize our understanding of environmental, ecological, and evolutionary change across the Americas. To bring clarity to the question of when the Isthmus of Panama formed, we provide an exhaustive review and reanalysis of geological, paleontological, and molecular records. These independent lines of evidence converge upon a cohesive narrative of gradually emerging land and constricting seaways,withformationof theIsthmus of Panama sensustricto around 2.8 Ma. The evidence used to support an older isthmus is inconclusive, and we caution against the uncritical acceptance of an isthmus before the Pliocene.Facultad de Ciencias Naturales y Muse

†Kenyaichthyidae fam. nov and †Kenyaichthys gen. nov - First Record of a Fossil Aplocheiloid Killifish (Teleostei, Cyprinodontiformes)

The extant Cyprinodontiformes (killifishes) with their two suborders Cyprinodontoidei and Aplocheiloidei represent a diverse and well-studied group of fishes. However, their fossil record is comparatively sparse and has so far yielded members of the Cyprinodontoidei only. Here we report on cyprinodontiform fossils from the upper Miocene Lukeino Formation in the Tugen Hills of the Central Rift Valley of Kenya, which represent the first fossil record of an aplocheiloid killifish. A total of 169 specimens - mostly extraordinarily well preserved and a sample of ten extant cyprinodontiform species were studied on the basis of morphometrics, meristics and osteology. A phylogenetic analysis using PAUP was also conducted for the fossils. Both the osteological data and the phylogenetic analysis provide strong evidence for the assignment of the fossils to the Aplocheiloidei, and justify the definition of the new family dagger Kenyaichthyidae, the new genus dagger Kenyaichthys and the new species dagger K. kipkechi sp. nov. The phylogenetic analysis unexpectedly places dagger Kenyaichthys gen. nov. in a sister relationship to the Rivulidae (a purely Neotropical group),a probable explanation might be lack of available synapomorphies for the Rivulidae, Nothobranchiidae and Aplocheilidae. The specimens of dagger K. kipkechi sp. nov. show several polymorphic characters and large overlap in meristic traits, which justifies their interpretation as a species flock in statu nascendi. Patterns of variation in neural and haemal spine dimensions in the caudal vertebrae of dagger Kenyaichthys gen. nov. and the extant species studied indicate that some previously suggested synapomorphies of the Cyprinodontoidei and Aplocheiloidei need to be revised

The Great American Biotic Interchange: Dispersals, Tectonics, Climate, Sea Level and Holding Pens

The biotic and geologic dynamics of the Great American Biotic Interchange are reviewed and revised. Information on the Marine Isotope Stage chronology, sea level changes as well as Pliocene and Pleistocene vegetation changes in Central and northern South America add to a discussion of the role of climate in facilitating trans-isthmian exchanges. Trans-isthmian land mammal exchanges during the Pleistocene glacial intervals appear to have been promoted by the development of diverse non-tropical ecologies