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2.
Rand Health Q ; 9(1): 1, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32742743

ABSTRACT

This study, sponsored by the American Medical Association (AMA), describes how alternative payment models (APMs) affect physicians, physicians' practices, and hospital systems in the United States and also provides updated data to the original 2014 study. Payment models discussed are core payment (fee for service, capitation, episode-based and bundled), supplementary payment (shared savings, pay for performance, retainer-based), and combined payment (medical homes and accountable care organizations). The effects of changes since 2014 in the Affordable Care Act (ACA) and of new alternative payment models (APMs), such as the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) Quality Payment Program (QPP), are also examined. This project uses the same qualitative multiple-case study method as the 2014 study, relying primarily on semistructured interviews with physician practice leaders, physicians, and other observers. Findings describe the challenges posed by APMs, strategies adopted to deal with APMs, the effects of rapidly changing and increasingly complex payment models, and how risk aversion influences physician practices' decisions to engage in new payment models. Project findings are intended to help guide efforts by the AMA and other stakeholders to improve current and future APMs and help physician practices succeed in them.

3.
Palaeontology ; 63(1): 103-115, 2020 Jan.
Article in English | MEDLINE | ID: mdl-32025055

ABSTRACT

Fossils are a key source of data on the evolution of feather structure and function through deep time, but their ability to resolve macroevolutionary questions is compromised by an incomplete understanding of their taphonomy. Critically, the relative preservation potential of two key feather components, melanosomes and keratinous tissue, is not fully resolved. Recent studies suggesting that melanosomes are preferentially preserved conflict with observations that melanosomes preserve in fossil feathers as external moulds in an organic matrix. To date, there is no model to explain the latter mode of melanosome preservation. We addressed these issues by degrading feathers in systematic taphonomic experiments incorporating decay, maturation and oxidation in isolation and combination. Our results reveal that the production of mouldic melanosomes requires interactions with an oxidant and is most likely to occur prior to substantial maturation. This constrains the taphonomic conditions under which melanosomes are likely to be fossilized. Critically, our experiments also confirm that keratinous feather structures have a higher preservation potential than melanosomes under a range of diagenetic conditions, supporting hitherto controversial hypotheses that fossil feathers can retain degraded keratinous structures.

4.
Adm Policy Ment Health ; 47(3): 357-365, 2020 05.
Article in English | MEDLINE | ID: mdl-31745735

ABSTRACT

The impact of initiatives aimed at reducing time in untreated psychosis during early-stage schizophrenia will be unknown for many years. Thus, we simulate the effect of earlier treatment entry and better antipsychotic drug adherence on schizophrenia-related hospitalizations, receipt of disability benefits, competitive employment, and independent/family living over a ten-year horizon. We predict that earlier treatment entry reduces hospitalizations by 12.6-14.4% and benefit receipt by 7.0-8.5%, while increasing independent/family living by 41.5-46% and employment by 42-58%. We predict larger gains if a pro-adherence intervention is also used. Our findings suggest substantial benefits of timely and consistent early schizophrenia care.


Subject(s)
Antipsychotic Agents/administration & dosage , Early Diagnosis , Medication Adherence , Schizophrenia/drug therapy , Forecasting , Humans , Prognosis , Schizophrenia/diagnosis , Treatment Outcome
5.
Early Interv Psychiatry ; 13(6): 1357-1365, 2019 12.
Article in English | MEDLINE | ID: mdl-30548103

ABSTRACT

AIM: Duration of untreated psychosis in early schizophrenia impacts long-term outcomes. Because long-acting injectable (LAI) antipsychotic drugs improve adherence in early-stage patients, they could reduce additional time in uncontrolled psychosis (TUP) during the critical period of the illness. However, the long-term benefit of early LAI use over oral formulations has not been quantified. This study explores the potential magnitude of the benefit with a simulation approach. METHODS: A microsimulation models the effects of 11 treatment pathways reflecting alternative decisions on whether and when LAI agents are used during a "calibration phase" that starts at treatment entry and lasts until the end of the 3-year critical period. Treatment failure prolongs time in psychosis. Long-term outcomes are predicted over the ensuing 7-year period as a function of TUP. RESULTS: An "early LAI" pathway where LAI treatment follows the second oral treatment failure is compared to an oral-only pathway. Under these pathways, 69% and 46% of patients, respectively, are estimated to exit the calibration phase with adequate symptom control (total positive and negative syndrome scale score below 68). Relative to the oral-only pathway, the early LAI pathway is predicted to increase competitive employment by 39% (25% vs 18%) and independent or family living by 22% (71% vs 58%), and to decrease receipt of disability benefits by 36% (42% vs 66%) and hospital admissions per 1000 patient-years by 15% (249% vs 294%). CONCLUSIONS: While these simulation results need to be confirmed empirically, they suggest that earlier use of LAI antipsychotics can meaningfully improve patient outcomes.


Subject(s)
Antipsychotic Agents/therapeutic use , Computer Simulation , Delayed-Action Preparations/therapeutic use , Schizophrenia/drug therapy , Antipsychotic Agents/administration & dosage , Humans , Injections , Schizophrenia/diagnosis
6.
Nat Ecol Evol ; 3(1): 24-30, 2019 01.
Article in English | MEDLINE | ID: mdl-30568282

ABSTRACT

Pterosaurs were the first vertebrates to achieve true flapping flight, but in the absence of living representatives, many questions concerning their biology and lifestyle remain unresolved. Pycnofibres-the integumentary coverings of pterosaurs-are particularly enigmatic: although many reconstructions depict fur-like coverings composed of pycnofibres, their affinities and function are not fully understood. Here, we report the preservation in two anurognathid pterosaur specimens of morphologically diverse pycnofibres that show diagnostic features of feathers, including non-vaned grouped filaments and bilaterally branched filaments, hitherto considered unique to maniraptoran dinosaurs, and preserved melanosomes with diverse geometries. These findings could imply that feathers had deep evolutionary origins in ancestral archosaurs, or that these structures arose independently in pterosaurs. The presence of feather-like structures suggests that anurognathids, and potentially other pterosaurs, possessed a dense filamentous covering that probably functioned in thermoregulation, tactile sensing, signalling and aerodynamics.


Subject(s)
Dinosaurs/anatomy & histology , Feathers/anatomy & histology , Integumentary System/anatomy & histology , Animals , Fossils , Melanosomes
7.
Behav Neurosci ; 132(6): 580-586, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30160507

ABSTRACT

Acetaminophen (also known as paracetamol) is a commonly used over-the-counter pain medication, but recent evidence suggests that a single exposure or prenatal exposure may have significant behavioral effects. This investigation aimed to determine whether acetaminophen could disrupt memory formation in an object-recognition task and to quantify potential changes in memory-related signaling cascades in the hippocampus of mice after acetaminophen administration. Using male mice, we examined the effect of a single subcutaneous injection of acetaminophen on the object-recognition task, a single-trial, hippocampus-dependent memory task. We also investigated potential changes in the activation of extracellular signal-regulated kinase (ERK) in the dorsal mouse hippocampus 1 hr after a subcutaneous injection of acetaminophen. We found that 50 mg/kg and 100 mg/kg interfered with performance in the object-recognition memory task, whereas 10 mg/kg did not. We also found that a single 50 mg/kg injection of acetaminophen significantly increased p42 ERK phosphorylation in the dorsal mouse hippocampus. Overall, these results suggest that a single dose of acetaminophen can have significant effects on memory and alters signaling kinases critical for memory consolidation. Further work is needed to determine the involved mechanisms. (PsycINFO Database Record (c) 2018 APA, all rights reserved).


Subject(s)
Acetaminophen/pharmacology , Extracellular Signal-Regulated MAP Kinases/metabolism , Hippocampus/drug effects , Psychotropic Drugs/pharmacology , Recognition, Psychology/drug effects , Analgesics, Non-Narcotic/pharmacology , Animals , Dose-Response Relationship, Drug , Hippocampus/enzymology , Male , Mice, Inbred C57BL , Phosphorylation/drug effects , Random Allocation , Recognition, Psychology/physiology
8.
Nat Commun ; 9(1): 2878, 2018 07 23.
Article in English | MEDLINE | ID: mdl-30038333

ABSTRACT

The soft tissues of many fossil vertebrates preserve evidence of melanosomes-micron-scale organelles that inform on integumentary coloration and communication strategies. In extant vertebrates, however, melanosomes also occur in internal tissues. Hence, fossil melanosomes may not derive solely from the integument and its appendages. Here, by analyzing extant and fossil frogs, we show that non-integumentary melanosomes have high fossilization potential, vastly outnumber those from the skin, and potentially dominate the melanosome films preserved in some fossil vertebrates. Our decay experiments show that non-integumentary melanosomes usually remain in situ provided that carcasses are undisturbed. Micron-scale study of fossils, however, demonstrates that non-integumentary melanosomes can redistribute through parts of the body if carcasses are disturbed by currents. Collectively, these data indicate that fossil melanosomes do not always relate to integumentary coloration. Integumentary and non-integumentary melanosomes can be discriminated using melanosome geometry and distribution. This is essential to accurate reconstructions of the integumentary colours of fossil vertebrates.


Subject(s)
Anura/physiology , Color , Fossils , Melanosomes/metabolism , Xenopus/physiology , Animals , Biological Evolution , Feathers , Iguanas/physiology , Melanins/chemistry , Pigmentation , Skin/metabolism , Vertebrates , Xenopus laevis
9.
Nat Commun ; 9(1): 2072, 2018 05 25.
Article in English | MEDLINE | ID: mdl-29802246

ABSTRACT

Feathers are remarkable evolutionary innovations that are associated with complex adaptations of the skin in modern birds. Fossilised feathers in non-avian dinosaurs and basal birds provide insights into feather evolution, but how associated integumentary adaptations evolved is unclear. Here we report the discovery of fossil skin, preserved with remarkable nanoscale fidelity, in three non-avian maniraptoran dinosaurs and a basal bird from the Cretaceous Jehol biota (China). The skin comprises patches of desquamating epidermal corneocytes that preserve a cytoskeletal array of helically coiled α-keratin tonofibrils. This structure confirms that basal birds and non-avian dinosaurs shed small epidermal flakes as in modern mammals and birds, but structural differences imply that these Cretaceous taxa had lower body heat production than modern birds. Feathered epidermis acquired many, but not all, anatomically modern attributes close to the base of the Maniraptora by the Middle Jurassic.


Subject(s)
Biological Coevolution , Birds/physiology , Dinosaurs/physiology , Epidermis/physiology , Feathers/physiology , Animals , Epidermis/ultrastructure , Feathers/ultrastructure , Fossils , Microscopy, Electron, Scanning , Phylogeny
11.
Palaeontology ; 59(3): 337-350, 2016 May.
Article in English | MEDLINE | ID: mdl-27499556

ABSTRACT

Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origins of sulfur-bearing compounds in fossil melanosomes are difficult to resolve. This has implications for interpretations of original colour in fossils based on potential sulfur-rich phaeomelanosomes. Here we use pyrolysis gas chromatography mass spectrometry (Py-GCMS), fourier transform infrared spectroscopy (FTIR) and time of flight secondary ion mass spectrometry (ToF-SIMS) to assess the mode of preservation of fossil microstructures, confirmed as melanosomes based on the presence of melanin, preserved in frogs from the Late Miocene Libros biota (NE Spain). Our results reveal a high abundance of organosulfur compounds and non-sulfurized fatty acid methyl esters in both the fossil tissues and host sediment; chemical signatures in the fossil tissues are inconsistent with preservation of phaeomelanin. Our results reflect preservation via the diagenetic incorporation of sulfur, i.e. sulfurization (natural vulcanization), and other polymerization processes. Organosulfur compounds and/or elevated concentrations of sulfur have been reported from melanosomes preserved in various invertebrate and vertebrate fossils and depositional settings, suggesting that preservation through sulfurization is likely to be widespread. Future studies of sulfur-rich fossil melanosomes require that the geochemistry of the host sediment is tested for evidence of sulfurization in order to constrain interpretations of potential phaeomelanosomes and thus of original integumentary colour in fossils.

12.
Curr Biol ; 26(8): 1075-82, 2016 04 25.
Article in English | MEDLINE | ID: mdl-27040775

ABSTRACT

Evidence of original coloration in fossils provides insights into the visual communication strategies used by ancient animals and the functional evolution of coloration over time [1-7]. Hitherto, all reconstructions of the colors of reptile integument and the plumage of fossil birds and feathered dinosaurs have been of melanin-based coloration [1-6]. Extant animals also use other mechanisms for producing color [8], but these have not been identified in fossils. Here we report the first examples of carotenoid-based coloration in the fossil record, and of structural coloration in fossil integument. The fossil skin, from a 10 million-year-old colubrid snake from the Late Miocene Libros Lagerstätte (Teruel, Spain) [9, 10], preserves dermal pigment cells (chromatophores)-xanthophores, iridophores, and melanophores-in calcium phosphate. Comparison with chromatophore abundance and position in extant reptiles [11-15] indicates that the fossil snake was pale-colored in ventral regions; dorsal and lateral regions were green with brown-black and yellow-green transverse blotches. Such coloration most likely functioned in substrate matching and intraspecific signaling. Skin replicated in authigenic minerals is not uncommon in exceptionally preserved fossils [16, 17], and dermal pigment cells generate coloration in numerous reptile, amphibian, and fish taxa today [18]. Our discovery thus represents a new means by which to reconstruct the original coloration of exceptionally preserved fossil vertebrates.


Subject(s)
Carotenoids/metabolism , Colubridae/physiology , Fossils , Skin Pigmentation/physiology , Animals , Chromatophores/physiology , Melanins/metabolism
13.
Rand Health Q ; 6(1): 9, 2016 Jun 20.
Article in English | MEDLINE | ID: mdl-28083437

ABSTRACT

In this article, the authors explore why medical device innovation has traditionally been geared so thoroughly toward improving performance, with little regard to cost. They argue that the changing incentives in the health care sector and the move to value-based payment models, accelerated by the implementation of the Affordable Care Act, will force device manufacturers to redirect investments from the spectacular toward the prudent, which they dub "the end of sexy." The authors explore consequences for manufacturers, investors, and policymakers.

14.
Biol Psychiatry ; 77(9): 785-93, 2015 May 01.
Article in English | MEDLINE | ID: mdl-25064419

ABSTRACT

BACKGROUND: Deletion of the recurrent ~600 kb BP4-BP5 chromosomal region 16p11.2 has been associated with a wide range of neurodevelopmental outcomes. METHODS: To clarify the phenotype of 16p11.2 deletion, we examined the psychiatric and developmental presentation of predominantly clinically referred individuals, with a particular emphasis on broader autism phenotype characteristics in individuals with recurrent ~600 kb chromosome 16p11.2 deletions. Using an extensive standardized assessment battery across three clinical sites, 85 individuals with the 16p11.2 deletion and 153 familial control subjects were evaluated for symptom presentation and clinical diagnosis. RESULTS: Individuals with the 16p11.2 deletion presented with a high frequency of psychiatric and developmental disorders (>90%). The most commonly diagnosed conditions were developmental coordination disorder, phonologic processing disorder, expressive and receptive language disorders (71% of individuals >3 years old with a speech and language-related disorder), and autism spectrum disorder. Individuals with the 16p11.2 deletion not meeting diagnostic criteria for autism spectrum disorder had a significantly higher prevalence of autism-related characteristics compared with the familial noncarrier control group. Individuals with the 16p11.2 deletion had a range of intellectual ability, but IQ scores were 26 points lower than noncarrier family members on average. CONCLUSIONS: Clinically referred individuals with the 16p11.2 deletion have high rates of psychiatric and developmental disorders and provide a genetically well-defined group to study the emergence of developmental difficulties, particularly associated with the broader autism phenotype.


Subject(s)
Chromosome Deletion , Chromosomes, Human, Pair 16 , Cognition , Developmental Disabilities/genetics , Mental Disorders/genetics , Phenotype , Adolescent , Child , Child, Preschool , Developmental Disabilities/physiopathology , Developmental Disabilities/psychology , Heterozygote , Humans , Intelligence/genetics , Mental Disorders/physiopathology , Mental Disorders/psychology , Young Adult
15.
J R Soc Interface ; 11(100): 20140736, 2014 Nov 06.
Article in English | MEDLINE | ID: mdl-25185581

ABSTRACT

Nature's most spectacular colours originate in integumentary tissue architectures that scatter light via nanoscale modulations of the refractive index. The most intricate biophotonic nanostructures are three-dimensional crystals with opal, single diamond or single gyroid lattices. Despite intense interest in their optical and structural properties, the evolution of such nanostructures is poorly understood, due in part to a lack of data from the fossil record. Here, we report preservation of single diamond (Fd-3m) three-dimensional photonic crystals in scales of a 735,000 year old specimen of the brown Nearctic weevil Hypera diversipunctata from Gold Run, Canada, and in extant conspecifics. The preserved red to green structural colours exhibit near-field brilliancy yet are inconspicuous from afar; they most likely had cryptic functions in substrate matching. The discovery of pristine fossil examples indicates that the fossil record is likely to yield further data on the evolution of three-dimensional photonic nanostructures and their biological functions.


Subject(s)
Biological Evolution , Diamond , Fossils , Plants , Canada
16.
Biol Lett ; 9(3): 20130184, 2013 Jun 23.
Article in English | MEDLINE | ID: mdl-23536445

ABSTRACT

Fossil feathers often preserve evidence of melanosomes-micrometre-scale melanin-bearing organelles that have been used to infer original colours and patterns of the plumage of dinosaurs. Such reconstructions acknowledge that evidence from other colour-producing mechanisms is presently elusive and assume that melanosome geometry is not altered during fossilization. Here, we provide the first test of this assumption, using high pressure-high temperature autoclave experiments on modern feathers to simulate the effects of burial on feather colour. Our experiments show that melanosomes are retained despite loss of visual evidence of colour and complete degradation of other colour-producing structures (e.g. quasi-ordered arrays in barbs and the keratin cortex in barbules). Significantly, however, melanosome geometry and spatial distribution are altered by the effects of pressure and temperature. These results demonstrate that reconstructions of original plumage coloration in fossils where preserved features of melanosomes are affected by diagenesis should be treated with caution. Reconstructions of fossil feather colour require assessment of the extent of preservation of various colour-producing mechanisms, and, critically, the extent of alteration of melanosome geometry.


Subject(s)
Color , Feathers , Fossils , Animals
17.
Learn Mem ; 20(3): 147-55, 2013 Feb 19.
Article in English | MEDLINE | ID: mdl-23422279

ABSTRACT

The mammalian target of rapamycin (mTOR) signaling pathway is an important regulator of protein synthesis and is essential for various forms of hippocampal memory. Here, we asked whether the enhancement of object recognition memory consolidation produced by dorsal hippocampal infusion of 17ß-estradiol (E(2)) is dependent on mTOR signaling in the dorsal hippocampus, and whether E(2)-induced mTOR signaling is dependent on dorsal hippocampal phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) activation. We first demonstrated that the enhancement of object recognition induced by E(2) was blocked by dorsal hippocampal inhibition of ERK, PI3K, or mTOR activation. We then showed that an increase in dorsal hippocampal ERK phosphorylation 5 min after intracerebroventricular (ICV) E(2) infusion was also blocked by dorsal hippocampal infusion of the three cell signaling inhibitors. Next, we found that ICV infusion of E(2) increased phosphorylation of the downstream mTOR targets S6K (Thr-421) and 4E-BP1 in the dorsal hippocampus 5 min after infusion, and that this phosphorylation was blocked by dorsal hippocampal infusion of inhibitors of ERK, PI3K, and mTOR. Collectively, these data demonstrate for the first time that activation of the dorsal hippocampal mTOR signaling pathway is necessary for E(2) to enhance object recognition memory consolidation and that E(2)-induced mTOR activation is dependent on upstream activation of ERK and PI3K signaling.


Subject(s)
Estradiol/pharmacology , Hippocampus/drug effects , Memory/drug effects , Recognition, Psychology/drug effects , Signal Transduction/drug effects , TOR Serine-Threonine Kinases/drug effects , Animals , Blotting, Western , Butadienes/pharmacology , Chromones/pharmacology , Estrogen Antagonists/pharmacology , Female , Injections, Intraventricular , MAP Kinase Signaling System/drug effects , Mice , Mice, Inbred C57BL , Mitogen-Activated Protein Kinase 1/drug effects , Mitogen-Activated Protein Kinase 1/metabolism , Morpholines/pharmacology , Nitriles/pharmacology , Ovariectomy , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Phosphorylation , Ribosomal Protein S6 Kinases, 90-kDa/physiology , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/antagonists & inhibitors
18.
PLoS One ; 7(6): e38966, 2012.
Article in English | MEDLINE | ID: mdl-22720004

ABSTRACT

This study examines the links between human perceptions, cognitive biases and neural processing of symmetrical stimuli. While preferences for symmetry have largely been examined in the context of disorders such as obsessive-compulsive disorder and autism spectrum disorders, we examine various these phenomena in non-clinical subjects and suggest that such preferences are distributed throughout the typical population as part of our cognitive and neural architecture. In Experiment 1, 82 young adults reported on the frequency of their obsessive-compulsive spectrum behaviors. Subjects also performed an emotional Stroop or variant of an Implicit Association Task (the OC-CIT) developed to assess cognitive biases for symmetry. Data not only reveal that subjects evidence a cognitive conflict when asked to match images of positive affect with asymmetrical stimuli, and disgust with symmetry, but also that their slowed reaction times when asked to do so were predicted by reports of OC behavior, particularly checking behavior. In Experiment 2, 26 participants were administered an oddball Event-Related Potential task specifically designed to assess sensitivity to symmetry as well as the OC-CIT. These data revealed that reaction times on the OC-CIT were strongly predicted by frontal electrode sites indicating faster processing of an asymmetrical stimulus (unparallel lines) relative to a symmetrical stimulus (parallel lines). The results point to an overall cognitive bias linking disgust with asymmetry and suggest that such cognitive biases are reflected in neural responses to symmetrical/asymmetrical stimuli.


Subject(s)
Cerebral Cortex/physiopathology , Cognition , Conflict, Psychological , Visual Perception , Adult , Child , Child Development Disorders, Pervasive/physiopathology , Evoked Potentials , Female , Humans , Male , Obsessive-Compulsive Disorder/physiopathology
19.
Horm Behav ; 61(4): 487-95, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22265866

ABSTRACT

Although much recent work has elucidated the biochemical mechanisms underlying the modulation of memory by 17ß-estradiol, little is known about the signaling events through which progesterone (P) regulates memory. We recently demonstrated that immediate post-training infusion of P into the dorsal hippocampus enhances object recognition memory consolidation in young ovariectomized female mice (Orr et al., 2009). The goal of the present study was to identify the biochemical alterations that might underlie this mnemonic enhancement. We hypothesized that the P-induced enhancement of object recognition would be dependent on activation of the ERK and mTOR pathways. In young ovariectomized mice, we found that bilateral dorsal hippocampal infusion of P significantly increased levels of phospho-p42 ERK and the mTOR substrate S6K in the dorsal hippocampus 5 min after infusion. Phospho-p42 ERK levels were downregulated 15 min after infusion and returned to baseline 30 min after infusion, suggesting a biphasic effect of P on ERK activation. Dorsal hippocampal ERK and mTOR activation were necessary for P to facilitate memory consolidation, as suggested by the fact that inhibitors of both pathways infused into the dorsal hippocampus immediately after training blocked the P-induced enhancement of object recognition. Collectively, these data provide the first demonstration that the ability of P to enhance memory consolidation depends on the rapid activation of cell signaling and protein synthesis pathways in the dorsal hippocampus.


Subject(s)
Extracellular Signal-Regulated MAP Kinases/physiology , Hippocampus/physiology , Memory/drug effects , Progesterone/pharmacology , Recognition, Psychology/drug effects , Signal Transduction/drug effects , TOR Serine-Threonine Kinases/physiology , Animals , Blotting, Western , Butadienes/pharmacology , Data Interpretation, Statistical , Enzyme Activation/physiology , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Female , Hippocampus/drug effects , Hippocampus/enzymology , Mice , Mice, Inbred C57BL , Microinjections , Mitogen-Activated Protein Kinase Kinases/metabolism , Nitriles/pharmacology , Ovariectomy , Phosphorylation , Progesterone/administration & dosage , Protein Kinase Inhibitors/pharmacology , Ribosomal Protein S6 Kinases, 90-kDa/metabolism
20.
Proc Biol Sci ; 279(1731): 1114-21, 2012 Mar 22.
Article in English | MEDLINE | ID: mdl-21957131

ABSTRACT

Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.


Subject(s)
Coleoptera/anatomy & histology , Color , Animals , Coleoptera/ultrastructure , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Models, Biological , Nanostructures/chemistry , Nanostructures/ultrastructure
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