58 research outputs found

    High-Frequency Dynamics of Ocean pH: A Multi-Ecosystem Comparison

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    The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO2, reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO2, often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO2. Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change

    Resistance to cancer chemotherapy: failure in drug response from ADME to P-gp

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    Comprehensive molecular characterization of the hippo signaling pathway in cancer

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    Hippo signaling has been recognized as a key tumor suppressor pathway. Here, we perform a comprehensive molecular characterization of 19 Hippo core genes in 9,125 tumor samples across 33 cancer types using multidimensional “omic” data from The Cancer Genome Atlas. We identify somatic drivers among Hippo genes and the related microRNA (miRNA) regulators, and using functional genomic approaches, we experimentally characterize YAP and TAZ mutation effects and miR-590 and miR-200a regulation for TAZ. Hippo pathway activity is best characterized by a YAP/TAZ transcriptional target signature of 22 genes, which shows robust prognostic power across cancer types. Our elastic-net integrated modeling further reveals cancer-type-specific pathway regulators and associated cancer drivers. Our results highlight the importance of Hippo signaling in squamous cell cancers, characterized by frequent amplification of YAP/TAZ, high expression heterogeneity, and significant prognostic patterns. This study represents a systems-biology approach to characterizing key cancer signaling pathways in the post-genomic era

    Puerarin dry powder inhaler formulations for pulmonary delivery:Development and characterization

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    This study aims at developing and characterizing the puerarin dry powder inhaler (DPI) formulations for pulmonary delivery. The inhalable particles size (<2 μm) was accomplished by micronization and its morphology was examined by scanning electron microscopy (SEM). The puerarin-excipient interaction in powder mixtures was analyzed by using Fourier transform infrared spectroscopy (FTIR), Raman confocal microscopy, X-Ray powder Diffraction (XRD), and differential scanning calorimetry (DSC) methods. Using a Twin stage impinger (TSI), the in-vitro aerosolization of the powder formulations was carried out at a flow rate of 60 L/min and the drug was quantified by employing a validated HPLC method. No significant interactions between the drug and the excipients were observed in the powder formulations. The fine particle fraction (FPF) of the drug alone was 4.2% which has increased five to sixfold for the formulations with aerosolization enhancers. Formulation containing lactose as large carriers produced 32.7% FPF, which further increased with the addition of dispersibility enhancers, leucine and magnesium stearate (40.8% and 41.2%, respectively). The Raman and FTIR techniques are very useful tool for understanding structural integrity and stability of the puerarin in the powder formulations. The puerarin was found to be compatible with the excipients used and the developed DPI formulation may be considered as an efficient formulation for pulmonary delivery for the management of various diseases at a very low dose.</p

    Excipient Interactions in Glucagon Dry Powder Inhaler Formulation for Pulmonary Delivery

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    Purpose: This study describes the development and characterization of glucagon dry powder inhaler (DPI) formulation for pulmonary delivery. Lactose monohydrate, as a carrier, and L-leucine and magnesium stearate (MgSt) were used as dispersibility enhancers for this formulation. Methods: Using Fourier-transform infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), and Raman confocal microscopy, the interactions between glucagon and all excipients were characterized. The fine particle fractions (FPFs) of glucagon in different formulations were determined by a twin stage impinger (TSI) using a 2.5% glucagon mixture, and the glucagon concentration was measured by a validated LC-MS/MS method. Results: The FPF of the glucagon was 6.4%, which increased six-fold from the formulations with excipients. The highest FPF (36%) was observed for the formulation containing MgSt and large carrier lactose. The FTIR, Raman, and DSC data showed remarkable physical interactions of glucagon with leucine and a minor interaction with lactose; however, there were no interactions with MgSt alone or mixed with lactose. Conclusion: Due to the interaction between L-leucine and glucagon, leucine was not a suitable excipient for glucagon formulation. In contrast, the use of lactose and MgSt could be considered to prepare an efficient DPI formulation for the pulmonary delivery of glucagon
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