SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Crystallin

170

Coleoid cephalopods have an elaborate camera eye whereas nautiloids have primitive pinhole eye without lens and cornea. The Nautilus pinhole eye provides a unique example to explore the module of lens formation and its evolutionary mechanism. Here, we conducted an RNA-seq study of developing eyes of Nautilus and pygmy squid. First, we found that evolutionary distances from the common ancestor to Nautilus or squid are almost the same. Although most upstream eye development controlling genes were expressed in both species, six3/6 that are required for lens formation in vertebrates was not expressed in Nautilus. Furthermore, many downstream target genes of six3/6 including crystallin genes and other lens protein related genes were not expressed in Nautilus. As six3/6 and its controlling pathways are widely conserved among molluscs other than Nautilus, the present data suggest that deregulation of the six3/6 pathway led to the pinhole eye evolution in Nautilus.

Concepts: Gene expression, Evolution, Eye, Lens, Mollusca, Crystallin, Cephalopod, Nautilus

47

Radiation cataracts develop as a consequence of the effects of ionizing radiation on the development of the lens of the eye with an opaque lens reducing or eliminating the ability to see. Therefore, we would expect cataracts to be associated with reduced fitness in free-living animals.

Concepts: Photosynthesis, Ionizing radiation, Ultraviolet, Eye, Cornea, Lens, Radiation poisoning, Crystallin

29

This paper presents the response of the Health Protection Agency (HPA) to the 2011 statement from the International Commission on Radiological Protection (ICRP) on tissue reactions and recommendation of a reduced dose limit for the lens of the eye. The response takes the form of a brief review of the most recent epidemiological and mechanistic evidence. This is presented together with a discussion of dose limits in the context of the related risk and the current status of eye dosimetry, which is relevant for implementation of the limits. It is concluded that although further work is desirable to quantify better the risk at low doses and following protracted exposures, along with research into the mechanistic basis for radiation cataractogenesis to inform selection of risk projection models, the HPA endorses the conclusion reached by the ICRP in their 2011 statement that the equivalent dose limit for the lens of the eye should be reduced from 150 to 20 mSv per year, averaged over a five year period, with no year’s dose exceeding 50 mSv.

Concepts: Eye, Cornea, Lens, Crystallin

24

The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 µSv for the first operator, 8.7 µSv for the second operator/nurse and 0.50 µSv for radiographer. Corresponding values for cardiac resynchronisation therapy procedures were 30, 26 and 2.0 µSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures.

Concepts: Patient, Radiography, Patience, Eye, Radiology, Cornea, Lens, Crystallin

23

To determine the eye lens dose of the Interventional Cardiology (IC) personnel using optically stimulated luminescent dosimeter (OSLD) and the prevalence and risk of radiation - associated lens opacities in Thailand.

Concepts: Cardiology, Eye, Cornea, Interventional cardiology, Lens, Crystallin

20

Paraphrasing Dobzhansky’s famous dictum, I discuss how interrogating cancer through the lens of evolution has transformed our understanding of its development, causality and treatment resistance. The emerging picture of cancer captures its extensive diversity and therapeutic resilience, highlighting the need for more innovative approaches to control.

Concepts: Evolution, Evolutionary biology, Lens, Crystallin

12

The light environment of the mesopelagic realm of the ocean changes with both depth and viewer orientation, and this has probably driven the high diversity of visual adaptations found among its inhabitants. The mesopelagic ‘cockeyed’ squids of family Histioteuthidae have unusual eyes, as the left and right eyes are dimorphic in size, shape and sometimes lens pigmentation. This dimorphism may be an adaptation to the two different sources of light in the mesopelagic realm, with the large eye oriented upward to view objects silhouetted against the dim, downwelling sunlight and the small eye oriented slightly downward to view bioluminescent point sources. We used in situ video footage from remotely operated vehicles in the Monterey Submarine Canyon to observe the orientation behaviour of 152 Histioteuthis heteropsis and nine Stigmatoteuthis dofleini We found evidence for upward orientation in the large eye and slightly downward orientation in the small eye, which was facilitated by a tail-up oblique body orientation. We also found that 65% of adult H. heteropsis (n = 69) had yellow pigmentation in the lens of the larger left eye, which may be used to break the counterillumination camouflage of their prey. Finally, we used visual modelling to show that the visual returns provided by increasing eye size are much higher for an upward-oriented eye than for a downward-oriented eye, which may explain the development of this unique visual strategy.This article is part of the themed issue ‘Vision in dim light’.

Concepts: Light, Sunlight, Eye, Visual perception, Cornea, Lens, Book of Optics, Crystallin

7

Since the 1930s, Mexico has made substantial progress in providing adolescents with sexuality education through an evolving national school-based program. As part of a broader effort to document strategies to build support for and deal with resistance to sexuality education, this analysis uses a historical lens to answer 2 key questions: (1) How has the nature of sexuality education in Mexico evolved from the 1930s to the 2010s? (2) How have the drivers, responses, support, and resistance to sexuality education impacted Mexico’s experience implementing and sustaining school-based sexuality education?

Concepts: DNA, Biodiversity, Evolution, Metabolism, Antibiotic resistance, Creation–evolution controversy, Creationism, Crystallin

6

It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals.

Concepts: Evolution, Evolutionary biology, Eye, Crystallin, Sperm whale, Whale, Colossal Squid, Giant squid

0

Hospital based workers that perform interventional radiology are at risk of reaching the eye lens dose limit of 20 mSv/y. These workers are exposed to the radiation scattered by the patient, which creates a complex field, with low radiation energy reaching the eyes of the medical staff from wide angles. Therefore, the dosemeter used in the assessment of the eye lens dose of interventional radiologists needs to respond accurately in such conditions. In this study, the angular response of a commercially available radiophotoluminescent glass dosemeter, GD-352M, was optimized via Monte Carlo simulations, aiming at its use as eye lens dosemeter in interventional radiology. The improved dosemeter was manufactured and then characterized in terms of Hp(3), the quantity recommended for eye lens dosimetry. Its response was compared to the IEC 62387:2012 requirements for Hp(3) and to requirements proposed specifically for eye lens dosemeters used in interventional radiology. The improved dosemeter meets the IEC 62387:2012 requirements for energy and angular response for Hp(3) and also shows good agreement with the more strict requisites proposed for eye lens dosemeters to be used in interventional radiology.

Concepts: Ionizing radiation, Eye, Radiology, Cornea, Monte Carlo, Lens, Interventional radiology, Crystallin