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1.
Proc Natl Acad Sci U S A ; 119(5)2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35078936

RESUMEN

The origin of the phenomenon known as the Great Unconformity has been a fundamental yet unresolved problem in the geosciences for over a century. Recent hypotheses advocate either global continental exhumation averaging 3 to 5 km during Cryogenian (717 to 635 Ma) snowball Earth glaciations or, alternatively, diachronous episodic exhumation throughout the Neoproterozoic (1,000 to 540 Ma) due to plate tectonic reorganization from supercontinent assembly and breakup. To test these hypotheses, the temporal patterns of Neoproterozoic thermal histories were evaluated for four North American locations using previously published medium- to low-temperature thermochronology and geologic information. We present inverse time-temperature simulations within a Bayesian modeling framework that record a consistent signal of relatively rapid, high-magnitude cooling of ∼120 to 200 °C interpreted as erosional exhumation of upper crustal basement during the Cryogenian. These models imply widespread, synchronous cooling consistent with at least ∼3 to 5 km of unroofing during snowball Earth glaciations, but also demonstrate that plate tectonic drivers, with the potential to cause both exhumation and burial, may have significantly influenced the thermal history in regions that were undergoing deformation concomitant with glaciation. In the cratonic interior, however, glaciation remains the only plausible mechanism that satisfies the required timing, magnitude, and broad spatial pattern of continental erosion revealed by our thermochronological inversions. To obtain a full picture of the extent and synchroneity of such erosional exhumation, studies on stable cratonic crust below the Great Unconformity must be repeated on all continents.

2.
Drug Metab Dispos ; 50(8): 1077-1086, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35636769

RESUMEN

Farnesoid X receptor (FXR) is a nuclear receptor known to markedly alter expression of major transporters and enzymes in the liver. However, its effects toward organic anion transporting polypeptides (OATP) 1B1 and 1B3 remain poorly characterized. Therefore, the present study was aimed at determining the effects of chenodeoxycholic acid (CDCA), a naturally occurring FXR agonist, on OATP1B expression in cynomolgus monkeys. Multiple administrations of 50 and 100 mg/kg of CDCA were first shown to significantly repress mRNA expression of SLCO1B1/3 approximately 60% to 80% in monkey livers. It also suppressed cytochrome P450 (CYP)7A1-mRNA and induced OSTα/ß-mRNA, which are well known targets of FXR and determinants of bile acid homeostasis. CDCA concomitantly decreased OATP1B protein abundance by approximately 60% in monkey liver. In contrast, multiple doses of 15 mg/kg rifampin (RIF), a pregnane X receptor agonist, had no effect on hepatic OATP1B protein, although it induced the intestinal P-glycoprotein and MR2 proteins by ∼2-fold. Moreover, multiple doses of CDCA resulted in a steady ∼2- to 10-fold increase of the OATP1B biomarkers coproporphyrins (CPs) in the plasma samples collected prior to each CDCA dose. Additionally, 3.4- to 11.2-fold increases of CPI and CPIII areas under the curve were observed after multiple administrations compared with the single dose and vehicle administration dosing groups. Taken together, these data suggest that CDCA represses the expression of OATP1B1 and OATP1B3 in monkeys. Further investigation of OATP1B downregulation by FXR in humans is warranted, as such downregulation effects may be involved in bile acid homeostasis and potential drug interactions in man. SIGNIFICANCE STATEMENT: Using gene expression and proteomics tools, as well as endogenous biomarker data, for the first time, we have demonstrated that OATP1B expression was suppressed and its activity was reduced in the cynomolgus monkeys following oral administration of 50 and 100 mg/kg/day of chenodeoxycholic acid (CDCA), a Farnesoid X receptor agonist, for 8 days. These results lead to a better understanding of OATP1B downregulation by CDCA and its role on bile acid and drug disposition.


Asunto(s)
Ácido Quenodesoxicólico , Coproporfirinas , Transportador 1 de Anión Orgánico Específico del Hígado , Animales , Ácidos y Sales Biliares , Biomarcadores/metabolismo , Ácido Quenodesoxicólico/metabolismo , Ácido Quenodesoxicólico/farmacología , Coproporfirinas/sangre , Coproporfirinas/metabolismo , Regulación hacia Abajo , Interacciones Farmacológicas , Humanos , Transportador 1 de Anión Orgánico Específico del Hígado/genética , Transportador 1 de Anión Orgánico Específico del Hígado/metabolismo , Macaca fascicularis/metabolismo , Transportadores de Anión Orgánico/genética , Transportadores de Anión Orgánico/metabolismo , ARN Mensajero
3.
Int J Toxicol ; 41(4): 291-296, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35656559

RESUMEN

The IQ Consortium NHP Reuse Working Group (WG) comprises members from 15 pharmaceutical and biotechnology companies. In 2020, the WG developed and distributed a detailed questionnaire on protein non-naïve NHP reuse to the WG member companies. The WG received responses from key stakeholders including principal investigators, facility managers, animal welfare officers and research scientists. This paper's content reflects the consolidated opinion of the WG members and the questionnaire responses on the subject of NHP reuse within nonclinical programs at all stages of research and development. Many of the pharmaceutical companies represented in the working group or participating in the questionnaire have already achieved some level of NHP reuse in their nonclinical programs, but the survey results suggested that there is significant potential to increase NHP reuse further and a need to understand the considerations involved in reuse more clearly. The WG has also focused carefully on the inherent concerns and risks of implementing protein non-naive NHP reuse and has evaluated the best methods of risk assessment and decision-making. This paper presents a discussion on the challenges and opportunities surrounding protein non-naïve NHP reuse and aims to stimulate further industry dialogue on the subject and provide guidance for pharmaceutical companies to establish roadmaps and decision trees enabling increased protein non-naïve NHP reuse. In addition, this paper represents a solid basis for collaborative engagement between pharmaceutical and biotechnology companies with contract research organizations (CROs) to discuss how the availability of protein non-naïve NHP within CROs can be better leveraged for their use within nonclinical studies.


Asunto(s)
Descubrimiento de Drogas , Primates , Animales , Evaluación Preclínica de Medicamentos/métodos , Industria Farmacéutica/métodos , Preparaciones Farmacéuticas
4.
J Pharmacol Exp Ther ; 375(1): 139-151, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-32719071

RESUMEN

Organic anion-transporting polypeptide (OATP) 1B induction is an evolving mechanism of drug disposition and interaction. However, there are contradictory reports describing OATP1B expression in hepatocytes and liver biopsies after administration of an inducer. This study investigated the in vivo effects of the common inducer rifampin (RIF) on the activity and expression of cynomolgus monkey OATP1B1 and OATP1B3 transporters, which are structurally and functionally similar their human OATP1B counterparts. Multiple doses of oral RIF (15 mg/kg) resulted in a steady 3.9-fold increase of CYP3A biomarker, 4ß-hydroxycholesterol (4ßHC), in the plasma samples collected before each RIF dose during the treatment period (i.e., predose). In contrast, the predose plasma levels of OATP1B biomarkers coproporphyrin (CP) I and CPIII did not change when compared with RIF treatment. The trough concentration, area under plasma concentration-time curve (AUC), and half-life of RIF decreased markedly during RIF treatment, suggesting that RIF induced its own clearance. Consequently, RIF treatment increased CPI and CPIII AUCs substantially after a single administration and, to a lesser extent, after multiple administrations compared with preadministration AUCs. In addition, OATP1B1 and OATP1B3 mRNA expressions were not modulated by RIF treatment (0.85-1.3-fold), whereas CYP3A8 expression was increased 3.7-5.0-fold, which correlated well with the predose levels of CP and 4ßHC. Rifampin treatment showed 2.0-3.3-fold increases in P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2) expression in the small intestine. Collectively, these findings indicate that monkey OATP1B and OATP1B3 are not induced by RIF, and further investigation of OATP1B induction by RIF and other nuclear receptor activators in humans is warranted. SIGNIFICANCE STATEMENT: In this study, combined endogenous biomarker and gene expression data suggested that RIF did not induce OATP1B in cynomolgus monkeys. For the first time, the study determines transporter gene expression in the nonhuman primate liver, gut, and kidney tissues after administration of RIF for 7 days, leading to a better understanding of the induction of OATP1B and other major drug transporters. Finally, it provides evidence to strengthen the claim that coproporphyrin is a suitable endogenous probe of OATP1B activity.


Asunto(s)
Coproporfirinas/sangre , Expresión Génica/efectos de los fármacos , Rifampin/farmacología , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones Orgánicos/biosíntesis , Animales , Biomarcadores/sangre , Femenino , Hidroxicolesteroles/sangre , Intestino Delgado/efectos de los fármacos , Intestino Delgado/metabolismo , Riñón/efectos de los fármacos , Riñón/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Macaca fascicularis , Masculino , Rifampin/administración & dosificación , Rifampin/sangre , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones Orgánicos/genética
5.
Bioorg Med Chem Lett ; 30(23): 127521, 2020 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-32882417

RESUMEN

In order to rapidly develop C6 and C8 SAR of our reported tricyclic sulfone series of RORγt inverse agonists, a late-stage bromination was employed. Although not regioselective, the bromination protocol allowed us to explore new substitution patterns/vectors that otherwise would have to be incorporated at the very beginning of the synthesis. Based on the SAR obtained from this exercise, compound 15 bearing a C8 fluorine was developed as a very potent and selective RORγt inverse agonist. This analog's in vitro profile, pharmacokinetic (PK) data and efficacy in an IL-23 induced mouse acanthosis model will be discussed.


Asunto(s)
Compuestos Heterocíclicos con 3 Anillos/uso terapéutico , Melanosis/tratamiento farmacológico , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/antagonistas & inhibidores , Sulfonas/uso terapéutico , Animales , Cristalografía por Rayos X , Agonismo Inverso de Drogas , Femenino , Compuestos Heterocíclicos con 3 Anillos/síntesis química , Compuestos Heterocíclicos con 3 Anillos/farmacocinética , Interleucina-18 , Masculino , Melanosis/inducido químicamente , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Estructura Molecular , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Unión Proteica , Relación Estructura-Actividad , Sulfonas/síntesis química , Sulfonas/farmacocinética
7.
Proc Natl Acad Sci U S A ; 112(51): 15574-9, 2015 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-26630002

RESUMEN

Weathering on mountain slopes converts rock to sediment that erodes into channels and thus provides streams with tools for incision into bedrock. Both the size and flux of sediment from slopes can influence channel incision, making sediment production and erosion central to the interplay of climate and tectonics in landscape evolution. Although erosion rates are commonly measured using cosmogenic nuclides, there has been no complementary way to quantify how sediment size varies across slopes where the sediment is produced. Here we show how this limitation can be overcome using a combination of apatite helium ages and cosmogenic nuclides measured in multiple sizes of stream sediment. We applied the approach to a catchment underlain by granodiorite bedrock on the eastern flanks of the High Sierra, in California. Our results show that higher-elevation slopes, which are steeper, colder, and less vegetated, are producing coarser sediment that erodes faster into the channel network. This suggests that both the size and flux of sediment from slopes to channels are governed by altitudinal variations in climate, vegetation, and topography across the catchment. By quantifying spatial variations in the sizes of sediment produced by weathering, this analysis enables new understanding of sediment supply in feedbacks between climate, tectonics, and mountain landscape evolution.

8.
Proc Natl Acad Sci U S A ; 112(39): 12030-5, 2015 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-26371325

RESUMEN

Exhumation of the southern Tibetan plateau margin reflects interplay between surface and lithospheric dynamics within the Himalaya-Tibet orogen. We report thermochronometric data from a 1.2-km elevation transect within granitoids of the eastern Lhasa terrane, southern Tibet, which indicate rapid exhumation exceeding 1 km/Ma from 17-16 to 12-11 Ma followed by very slow exhumation to the present. We hypothesize that these changes in exhumation occurred in response to changes in the loci and rate of rock uplift and the resulting southward shift of the main topographic and drainage divides from within the Lhasa terrane to their current positions within the Himalaya. At ∼17 Ma, steep erosive drainage networks would have flowed across the Himalaya and greater amounts of moisture would have advected into the Lhasa terrane to drive large-scale erosional exhumation. As convergence thickened and widened the Himalaya, the orographic barrier to precipitation in southern Tibet terrane would have strengthened. Previously documented midcrustal duplexing around 10 Ma generated a zone of high rock uplift within the Himalaya. We use numerical simulations as a conceptual tool to highlight how a zone of high rock uplift could have defeated transverse drainage networks, resulting in substantial drainage reorganization. When combined with a strengthening orographic barrier to precipitation, this drainage reorganization would have driven the sharp reduction in exhumation rate we observe in southern Tibet.

9.
Am J Community Psychol ; 60(1-2): 125-133, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27808408

RESUMEN

Housing instability can complicate parents' efforts to provide for their children. Child welfare service agencies have had difficulty adequately serving parents' housing needs due to limited and constrained funding streams. This article integrates the voices of four important stakeholders to illuminate how an innovative model of service system coordination called Linkages addresses housing needs for child welfare-involved parents eligible for public assistance. Facilitated by Linkages, these parents can receive supportive housing services through programs affiliated with the California public assistance program CalWORKs. Personal narratives reflecting the diverse perspectives of stakeholders in the Linkages collaboration-the statewide program director, a child welfare services coordinator, a CalWORKs caseworker, and a parent program participant-shed light on how the collaboration assists parents in attaining case plan goals, and highlights some of the factors facilitating and hindering effective collaboration between the agencies involved. Stakeholders emphasized the value of flexible service approaches, the intensity of the efforts required, the role of advocacy, and the importance of a shared vision between agencies working together to provide housing supports.


Asunto(s)
Servicios de Protección Infantil , Vivienda , Padres , Asistencia Pública , Servicio Social , California , Manejo de Caso , Conducta Cooperativa , Personas con Mala Vivienda , Humanos
10.
Bioorg Med Chem Lett ; 26(10): 2470-2474, 2016 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-27055941

RESUMEN

The synthesis and structure-activity relationship (SAR) of a series of pyridyl-isoxazole based agonists of S1P1 are discussed. Compound 5b provided potent in vitro activity with selectivity, had an acceptable pharmacokinetic profile, and demonstrated efficacy in a dose dependent manner when administered orally in a rodent model of arthritis.


Asunto(s)
Artritis Experimental/tratamiento farmacológico , Lisofosfolípidos/agonistas , Esfingosina/análogos & derivados , Relación Estructura-Actividad , Administración Oral , Animales , Técnicas de Química Sintética , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos/métodos , Humanos , Isoxazoles/química , Isoxazoles/farmacología , Recuento de Linfocitos , Masculino , Ratas Endogámicas Lew , Receptores de Lisoesfingolípidos/agonistas , Esfingosina/agonistas
11.
Proc Natl Acad Sci U S A ; 110(21): 8453-8, 2013 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-23650386

RESUMEN

The lifetime of the ancient lunar core dynamo has implications for its power source and the mechanism of field generation. Here, we report analyses of two 3.56-Gy-old mare basalts demonstrating that they were magnetized in a stable and surprisingly intense dynamo magnetic field of at least ~13 µT. These data extend the known lifetime of the lunar dynamo by ~160 My and indicate that the field was likely continuously active until well after the final large basin-forming impact. This likely excludes impact-driven changes in rotation rate as the source of the dynamo at this time in lunar history. Rather, our results require a persistent power source like precession of the lunar mantle or a compositional convection dynamo.

12.
J Pharmacol Exp Ther ; 354(2): 152-65, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26015463

RESUMEN

Therapies targeting either interleukin (IL)-23 or IL-17 have shown promise in treating T helper 17 (Th17)-driven autoimmune diseases. Although IL-23 is a critical driver of IL-17, recognition of nonredundant and independent functions of IL-23 and IL-17 has prompted the notion that dual inhibition of both IL-23 and IL-17 could offer even greater efficacy for treating autoimmune diseases relative to targeting either cytokine alone. To test this hypothesis, we generated selective inhibitors of IL-23 and IL-17 and tested the effect of either treatment alone compared with their combination in vitro and in vivo. In vitro, using a novel culture system of murine Th17 cells and NIH/3T3 fibroblasts, we showed that inhibition of both IL-23 and IL-17 completely suppressed IL-23-dependent IL-22 production from Th17 cells and cooperatively blocked IL-17-dependent IL-6 secretion from the NIH/3T3 cells to levels below either inhibitor alone. In vivo, in the imiquimod induced skin inflammation model, and in the myelin oligodendrocyte glycoprotein peptide-induced experimental autoimmune encephalomyelitis model, we demonstrated that dual inhibition of IL-17 and IL-23 was more efficacious in reducing disease than targeting either cytokine alone. Together, these data support the hypothesis that neutralization of both IL-23 and IL-17 may provide enhanced benefit against Th17 mediated autoimmunity and provide a basis for a therapeutic strategy aimed at dual targeting IL-23 and IL-17.


Asunto(s)
Autoinmunidad/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Interleucina-17/antagonistas & inhibidores , Interleucina-17/inmunología , Interleucina-23/antagonistas & inhibidores , Interleucina-23/inmunología , Animales , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Autoinmunidad/efectos de los fármacos , Técnicas de Cocultivo , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Femenino , Células HEK293 , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Células 3T3 NIH , Distribución Aleatoria
13.
Bioorg Med Chem Lett ; 24(15): 3268-73, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24980053

RESUMEN

Acylureas and acyclic imides are found to be excellent isosteres for 2-acylamino-1,3,4-thiadiazole in the azaxanthene-based series of glucocorticoid receptor (GR) agonists. The results reported herein show that primary acylureas maintain high affinity and selectivity for GR while providing improved CYP450 inhibition and pharmacokinetic profile over 2-acylamino-1,3,4-thiadiazoles. General methods for synthesis of a variety of acylureas and acyclic imides from a carboxylic acid were utilized and are described.


Asunto(s)
Descubrimiento de Drogas , Compuestos Heterocíclicos con 3 Anillos/farmacología , Receptores de Glucocorticoides/agonistas , Tiadiazoles/farmacología , Urea/farmacología , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Compuestos Heterocíclicos con 3 Anillos/síntesis química , Compuestos Heterocíclicos con 3 Anillos/química , Humanos , Modelos Moleculares , Estructura Molecular , Estereoisomerismo , Relación Estructura-Actividad , Tiadiazoles/química , Urea/análogos & derivados , Urea/química
14.
Sci Rep ; 14(1): 7175, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38532041

RESUMEN

The Mars Sample Return mission intends to retrieve a sealed collection of rocks, regolith, and atmosphere sampled from Jezero Crater, Mars, by the NASA Perseverance rover mission. For all life-related research, it is necessary to evaluate water availability in the samples and on Mars. Within the first Martian year, Perseverance has acquired an estimated total mass of 355 g of rocks and regolith, and 38 µmoles of Martian atmospheric gas. Using in-situ observations acquired by the Perseverance rover, we show that the present-day environmental conditions at Jezero allow for the hydration of sulfates, chlorides, and perchlorates and the occasional formation of frost as well as a diurnal atmospheric-surface water exchange of 0.5-10 g water per m2 (assuming a well-mixed atmosphere). At night, when the temperature drops below 190 K, the surface water activity can exceed 0.5, the lowest limit for cell reproduction. During the day, when the temperature is above the cell replication limit of 245 K, water activity is less than 0.02. The environmental conditions at the surface of Jezero Crater, where these samples were acquired, are incompatible with the cell replication limits currently known on Earth.

15.
J Immunol ; 184(7): 3917-26, 2010 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-20190141

RESUMEN

LFA-1 appears to play a central role in normal immune responses to foreign Ags. In autoimmune or inflammatory diseases, there is increased expression of LFA-1 and/or its counterligand, ICAM-1. Others have demonstrated that the targeted disruption of LFA-1:ICAM interactions, either by gene deletion or Ab treatment in mice, results in reduced leukocyte trafficking, inflammatory responses, and inhibition of inflammatory arthritis in the K/BxN serum transfer model. However, there has been little success in finding a small-molecule LFA-1 antagonist that can similarly impact rodent models of arthritis. In this paper, we present the first reported example of an LFA-1 small-molecule antagonist, BMS-587101, that is efficacious in preclinical disease models. In vitro, BMS-587101 inhibited LFA-1-mediated adhesion of T cells to endothelial cells, T cell proliferation, and Th1 cytokine production. Because BMS-587101 exhibits in vitro potency, cross-reactivity, and oral bioavailability in rodents, we evaluated the impact of oral administration of this compound in two different models of arthritis: Ab-induced arthritis and collagen-induced arthritis. Significant impact of BMS-587101 on clinical score in both models was observed, with inhibition comparable or better than anti-mouse LFA-1 Ab. In addition, BMS-587101 significantly reduced cytokine mRNA levels in the joints of Ab-induced arthritis animals as compared with those receiving vehicle alone. In paws taken from the collagen-induced arthritis study, the bones of vehicle-treated mice had extensive inflammation and bone destruction, whereas treatment with BMS-587101 resulted in marked protection. These findings support the potential use of an LFA-1 small-molecule antagonist in rheumatoid arthritis, with the capacity for disease modification.


Asunto(s)
Antiinflamatorios/farmacología , Artritis Experimental/tratamiento farmacológico , Inflamación/tratamiento farmacológico , Antígeno-1 Asociado a Función de Linfocito/metabolismo , Compuestos de Espiro/farmacología , Tiofenos/farmacología , Animales , Artritis Experimental/inmunología , Artritis Experimental/patología , Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Citocinas/biosíntesis , Citocinas/efectos de los fármacos , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Humanos , Inflamación/inmunología , Inflamación/patología , Prueba de Cultivo Mixto de Linfocitos , Antígeno-1 Asociado a Función de Linfocito/inmunología , Ratones
16.
Sci Adv ; 8(8): eabi6031, 2022 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-35213228

RESUMEN

Relative crustal motions along active faults generate earthquakes, and repeated earthquake cycles build mountain ranges over millions of years. However, the long-term summation of elastic, earthquake-related deformation cannot produce the deformation recorded within the rock record. Here, we provide an explanation for this discrepancy by showing that increases in strain facilitated by plastic deformation of Earth's crust during the earthquake cycle, in conjunction with isostatic deflection and erosion, transform relative fault motions that produce individual earthquakes to geologic deformations. We focus our study on the data-rich Santa Cruz Mountains, CA, USA and compare predicted and observed quantities for rock uplift, apatite (U-Th)/He thermochronology, topographic relief, 10Be-based erosion rates, and interseismic surface velocities. This approach reconciles these disparate records of mountain-building processes, allowing us to explicitly bridge decadal measures of deformation with that produced by millions of years of plate motion.

17.
Sci Adv ; 8(47): eabp9084, 2022 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-36417516

RESUMEN

Collocated crystal sizes and mineral identities are critical for interpreting textural relationships in rocks and testing geological hypotheses, but it has been previously impossible to unambiguously constrain these properties using in situ instruments on Mars rovers. Here, we demonstrate that diffracted and fluoresced x-rays detected by the PIXL instrument (an x-ray fluorescence microscope on the Perseverance rover) provide information about the presence or absence of coherent crystalline domains in various minerals. X-ray analysis and multispectral imaging of rocks from the Séítah formation on the floor of Jezero crater shows that they were emplaced as coarsely crystalline igneous phases. Olivine grains were then partially dissolved and filled by finely crystalline or amorphous secondary silicate, carbonate, sulfate, and chloride/oxychlorine minerals. These results support the hypothesis that Séítah formation rocks represent olivine cumulates altered by fluids far from chemical equilibrium at low water-rock ratios.

18.
Sci Adv ; 8(47): eabo4856, 2022 11 25.
Artículo en Inglés | MEDLINE | ID: mdl-36417517

RESUMEN

Perseverance's Mastcam-Z instrument provides high-resolution stereo and multispectral images with a unique combination of spatial resolution, spatial coverage, and wavelength coverage along the rover's traverse in Jezero crater, Mars. Images reveal rocks consistent with an igneous (including volcanic and/or volcaniclastic) and/or impactite origin and limited aqueous alteration, including polygonally fractured rocks with weathered coatings; massive boulder-forming bedrock consisting of mafic silicates, ferric oxides, and/or iron-bearing alteration minerals; and coarsely layered outcrops dominated by olivine. Pyroxene dominates the iron-bearing mineralogy in the fine-grained regolith, while olivine dominates the coarse-grained regolith. Solar and atmospheric imaging observations show significant intra- and intersol variations in dust optical depth and water ice clouds, as well as unique examples of boundary layer vortex action from both natural (dust devil) and Ingenuity helicopter-induced dust lifting. High-resolution stereo imaging also provides geologic context for rover operations, other instrument observations, and sample selection, characterization, and confirmation.

19.
Bioorg Med Chem Lett ; 21(15): 4633-7, 2011 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-21705217
20.
Bioanalysis ; 13(3): 147-159, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33543654

RESUMEN

Background: Surrogate monoclonal antibodies (mAbs) used in preclinical in vivo studies can be challenging to quantify due to lack of suitable immunoaffinity reagents or unavailability of the mAb protein sequence. Generic immunoaffinity reagents were evaluated to develop sensitive LC-MS/MS assays. Peptides of unknown sequence can be used for selective LC-MS quantification. Results: anti-mouse IgG1 was found to be an effective immunoaffinity reagent, enabling quantification of mouse IgG1 mAbs in mouse serum. Selective peptides of unknown sequence were applied for multiplex LC-MS quantification of two rat mAbs co-dosed in mouse. Conclusion: Generic anti-mouse IgG subtype-specific antibodies can be used to improve assay sensitivity and peptides of unknown sequence can be used to quantify surrogate mAbs when the mAb protein sequence in unavailable.


Asunto(s)
Anticuerpos Monoclonales/sangre , Cromatografía Liquida/métodos , Espectrometría de Masas en Tándem/métodos , Animales , Humanos , Ratones , Ratas
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