471 research outputs found
Histological techniques for marine bivalve molluscs: update
This chapter describes the procedures for determining the reproductive stage of oysters, mytilid mussels, and dreissenid mussels collected for NOAAâs National Status and Trends Mussel Watch Project. Analyses are conducted on paraffin-embedded tissues sectioned at a 5-ÎŒm thickness and stained using a pentachrome staining procedure. Each slide is examined microscopically to determine the animalâs sex and stage of gonadal development. A semi-quantitative ranking is assigned
PAT-based design of agrochemical co-crystallization processes : a case-study for the selective crystallization of 1:1 and 3:2 co-crystals of p-toluenesulfonamide/triphenylphosphine oxide
In this study, the selective crystallization and characterization of the stoichiometric forms of the p-toluenesulfonamide/triphenylphosphine oxide (p-TSA-TPPO) co-crystal system in acetonitrile (MeCN) is demonstrated using batch and semi-batch crystallizers. In the batch study, both 1:1 and 3:2 p-TSA-TPPO were successfully isolated as pure forms. However, process variability was observed in a few experimental runs. To address the batch process variability issue, a control strategy was implemented using temperature cycling, aided by in situ process analytical technologies (PAT) to convert from 3:2 to 1:1 p-TSA-TPPO. In the semi-batch co-crystallization studies, the two molecular co-formers, p-TSA and TPPO, were dissolved in MeCN and pumped separately to the crystallizer. Changing the flow rates of the respective active ingredients allowed control over the co-crystallization outcome, and presents as a promising opportunity for development of a continuous co-crystallization process
A laboratory study of overtopping and breaching of shingle barrier beaches
Shingle and mixed sand / shingle beaches are widespread in many parts of the UK and Europe. These beaches are highly efficient and practical forms of coastal protection, however a shingle beach in common with any other type of beach, can suffer erosion and subsequent landward retreat of the shoreline. Consequently over a period of time a beach
which was originally of satisfactory dimensions may be reduced to such an extent that it no longer constitutes an
acceptable âline of defenceâ. Anticipating this state is clearly important if shingle beaches are to be managed effectively, and landward structures are not to be damaged by flooding.
The classical dynamic equilibrium shingle beach profile has been described using the parametric model of Powell (1990). In theory, a dynamic equilibrium profile should develop for any given combination of wave conditions assuming that there is sufficient time and sediment available for the profile to form. This limitation means that the model is not valid for the prediction of overwashing and breaching of shingle barrier beaches.
However it has been used to estimate profile performance in
these circumstances (Buijs et al., 2005).
An empirical framework, based on extensive fieldwork and physical model data was developed to predict the threshold for breaching of shingle barrier beaches (Bradbury, 2000). The field and model data used to develop the model related only to the shingle barrier at Hurst Spit.
Bradbury et al (2005) found that model did not work so well
when applied to other sites and concluded that use of the
model outside the valid predictive range would result in the
under prediction of overwashing.
Further data was therefore required to test and extend the range of validity of the Bradbury model
Periodic steady-state flow crystallization of a pharmaceutical drug using MSMPR operation
AbstractIn this paper, a novel concept of periodic mixed suspension mixed product removal (PMSMPR) crystallization process is demonstrated. An integrated array of process analytical technologies (PATs), based on attenuated total reflectance ultra violet/visible spectroscopy, focused beam reflectance measurement, particle vision microscopy and Raman spectroscopy, and in-house developed crystallization process informatics system software (CryPRINS) were used to monitor the periodic steady-state flow crystallization of paracetamol. Periodic steady-state is a new concept defined as a state of a system that maintains itself despite transitory effects caused by periodic, but controlled disruptions (state of controlled operation). This work also illustrates the concept of âstate of controlled operationâ instead of âsteady-state operationâ as a state that can characterize continuous (periodic) operation. The PMSMPR was configured as either a single- or two-stage unit and operated for up to 11 residence times without blockage or encrustation problems. The number of PMSMPR stages, seed characteristics (size, shape and distribution), and use of recycle stream were the main variables that influenced the periodic operation, significantly affecting the extent of secondary nucleation and growth. The results further illustrate the use of PAT and information system tools together to determine when the periodic operation reaches a state of controlled operation (periodic steady-state). These tools provided a better understanding of the variables and operating procedures influencing the periodic operation
Longitudinal Associations of Neighborhood Crime and Perceived Safety with Blood Pressure: The Multi-Ethnic Study of Atherosclerosis (MESA)
Background: High neighborhood crime and low perceptions of safety may influence blood pressure (BP) through chronic stress. Few studies have examined these associations using longitudinal data. Methods: We used longitudinal data from 528 participants of the Multi-Ethnic Study of Atherosclerosis (aged 45-84, nonhypertensive at baseline) who lived in Chicago, Illinois. We examined associations of changes in individual-level perceived safety, aggregated neighborhood-level perceived safety, and past-year rates of police-recorded crime in a 1, =, or = mile buffer per 1,000 population with changes in systolic and diastolic BPs using fixed-effects linear regression. BP was measured five times between 2000 and 2012 and was adjusted for antihypertensive medication use (+10 mm Hg added to systolic and +5 mm Hg added to diastolic BP for participants on medication). Models were adjusted for time-varying sociodemographic and healthrelated characteristics and neighborhood socioeconomic status. We assessed differences by sex. Results: A standard deviation increase in individual-level perceived safety was associated with a 1.54 mm Hg reduction in systolic BP overall (95% confidence interval [CI]: 0.25, 2.83), and with a 1.24 mm Hg reduction in diastolic BP among women only (95% CI: 0.37, 2.12) in adjusted models. Increased neighborhood-level safety was not associated with BP change. An increase in police-recorded crime was associated with a reduction in systolic and diastolic BPs among women only, but results were sensitive to neighborhood buffer size. Conclusions: Results suggest individual perception of neighborhood safety may be particularly salient for systolic BP reduction relative to more objective neighborhood exposures
Evaluating the Effectiveness of Exploration and Accumulated Experience in Automatic Case Elicitation
Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record
Fil: GarcĂa, Rodolfo A.. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. General Roca. RĂo Negro; ArgentinaFil: FernĂĄndez, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. RĂo Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. NeuquĂ©n; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de PaleobiologĂa y GeologĂa. Universidad Nacional de RĂo Negro. NeuquĂ©n; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica. Anillaco. La Rioja; Argentin
Evolutionary origins of the estrogen signaling system : insights from amphioxus
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Steroid Biochemistry and Molecular Biology 127 (2011): 176â188, doi:10.1016/j.jsbmb.2011.03.022.Classically, the estrogen signaling system has two core components: cytochrome P450
aromatase (CYP19), the enzyme complex that catalyzes the rate limiting step in estrogen
biosynthesis; and estrogen receptors (ERs), ligand activated transcription factors that interact
with the regulatory region of target genes to mediate the biological effects of estrogen. While the
importance of estrogens for regulation of reproduction, development and physiology has been
well-documented in gnathostome vertebrates, the evolutionary origins of estrogen as a hormone
are still unclear. As invertebrates within the phylum Chordata, cephalochordates (e.g. the
amphioxus of the genus Branchiostoma) are among the closest invertebrate relatives of the
vertebrates and can provide critical insight into the evolution of vertebrate-specific molecules
and pathways. To address this question, this paper briefly reviews relevant earlier studies that
help to illuminate the history of the aromatase and ER genes, with a particular emphasis on
insights from amphioxus and other invertebrates. We then present new analyses of amphioxus
aromatase and ER sequence and function, including an in silico model of the amphioxus
aromatase protein, and CYP19 gene analysis. CYP19 shares a conserved gene structure with
vertebrates (9 coding exons) and moderate sequence conservation (40% amino acid identity with
human CYP19). Modeling of the amphioxus aromatase substrate binding site and simulated
docking of androstenedione in comparison to the human aromatase shows that the substrate
binding site is conserved and predicts that androstenedione could be a substrate for amphioxus
CYP19. The amphioxus ER is structurally similar to vertebrate ERs, but differs in sequence and
key residues of the ligand binding domain. Consistent with results from other laboratories,
amphioxus ER did not bind radiolabeled estradiol, nor did it modulate gene expression on an estrogen-responsive element (ERE) in the presence 59 of estradiol, 4-hydroxytamoxifen,
diethylstilbestrol, bisphenol A or genistein. Interestingly, it has been shown that a related gene,
the amphioxus âsteroid receptorâ (SR), can be activated by estrogens and that amphioxus ER can
repress this activation. CYP19, ER and SR are all primarily expressed in gonadal tissue,
suggesting an ancient paracrine/autocrinesignaling role, but it is not yet known how their
expression is regulated and, if estrogen is actually synthesized in amphioxus, whether it has a
role in mediating any biological effects . Functional studies are clearly needed to link emerging
bioinformatics and in vitro molecular biology results with organismal physiology to develop an
understanding of the evolution of estrogen signaling.Supported by grants from the NIEHS P42 ES07381 (GVC, SV) and EPA (STAR-RD831301)
(GVC), a Ruth L Kirschstein National Research Service Award (AT, F32 ES013092-01), an NIH
traineeship (SS, SG), a NATO Fellowship (AN) and the Boston University Undergraduate
Research Program (LC)
Mysterious Dust-emitting Object Orbiting TIC 400799224
We report the discovery of a unique object of uncertain nature - but quite possibly a disintegrating asteroid or minor planet - orbiting one star of the widely separated binary TIC 400799224. We initially identified the system in data from TESS Sector 10 via an abnormally shaped fading event in the light curve (hereafter "dips"). Follow-up speckle imaging determined that TIC 400799224 is actually two stars of similar brightness at 0.âł62 separation, forming a likely bound binary with projected separation of âŒ300 au. We cannot yet determine which star in the binary is host to the dips in flux. ASAS-SN and Evryscope archival data show that there is a strong periodicity of the dips at âŒ19.77 days, leading us to believe that an occulting object is orbiting the host star, though the duration, depth, and shape of the dips vary substantially. Statistical analysis of the ASAS-SN data shows that the dips only occur sporadically at a detectable threshold in approximately one out of every three to five transits, lending credence to the possibility that the occulter is a sporadically emitted dust cloud. The cloud is also fairly optically thick, blocking up to 37% or 75% of the light from the host star, depending on the true host. Further observations may allow for greater detail to be gleaned as to the origin and composition of the occulter, as well as to a determination of which of the two stars comprising TIC 400799224 is the true host star of the dips
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