Minimal basilar membrane motion in low-frequency hearing Warren, Rebecca L.; Ramamoorthy, Sripriya; Ciganović, Nikola ...
Proceedings of the National Academy of Sciences - PNAS,
07/2016, Letnik:
113, Številka:
30
Journal Article
Recenzirano
Odprti dostop
Low-frequency hearing is critically important for speech and music perception, but no mechanical measurements have previously been available from inner ears with intact low-frequency parts. These ...regions of the cochlea may function in ways different from the extensively studied high-frequency regions, where the sensory outer hair cells produce force that greatly increases the sound-evoked vibrations of the basilar membrane. We used laser interferometry in vitro and optical coherence tomography in vivo to study the low-frequency part of the guinea pig cochlea, and found that sound stimulation caused motion of a minimal portion of the basilar membrane. Outside the region of peak movement, an exponential decline in motion amplitude occurred across the basilar membrane. The moving region had different dependence on stimulus frequency than the vibrations measured near the mechanosensitive stereocilia. This behavior differs substantially from the behavior found in the extensively studied high-frequency regions of the cochlea.
Corals are very efficient at using solar radiation, with photosynthetic quantum efficiencies approaching theoretical limits. Here, we investigated potential mechanisms underlying such outstanding ...photosynthetic performance through extracting inherent optical properties of the living coral tissue and skeleton in a massive faviid coral. Using Monte Carlo simulations developed for medical tissue optics it is shown that for the investigated faviid coral, the coral tissue was a strongly light scattering matrix with a reduced scattering coefficient of μ
' = 10 cm
(at 636 nm). In contrast, the scattering coefficient of the coral skeleton was μ
' = 3.4 cm
, which facilitated the efficient propagation of light to otherwise shaded coral tissue layers, thus supporting photosynthesis in lower tissues. Our study provides a quantification of coral tissue optical properties in a massive faviid coral and suggests a novel light harvesting strategy, where tissue and skeletal optics act in concert to optimize the illumination of the photosynthesizing algal symbionts embedded within the living coral tissue.
Sensor-embedded phones are an emerging facilitator for participant-driven research studies. Skin cancer research is particularly amenable to this approach, as phone cameras enable self-examination ...and documentation of mole abnormalities that may signal a progression towards melanoma. Aggregation and open sharing of this participant-collected data can be foundational for research and the development of early cancer detection tools. Here we describe data from Mole Mapper, an iPhone-based observational study built using the Apple ResearchKit framework. The Mole Mapper app was designed to collect participant-provided images and measurements of moles, together with demographic and behavioral information relating to melanoma risk. The study cohort includes 2,069 participants who contributed 1,920 demographic surveys, 3,274 mole measurements, and 2,422 curated mole images. Survey data recapitulates associations between melanoma and known demographic risks, with red hair as the most significant factor in this cohort. Participant-provided mole measurements indicate an average mole size of 3.95 mm. These data have been made available to engage researchers in a collaborative, multidisciplinary effort to better understand and prevent melanoma.
Sound processing in the inner ear involves separation of the constituent frequencies along the length of the cochlea. Frequencies relevant to human speech (100 to 500 Hz) are processed in the apex ...region. Among mammals, the guinea pig cochlear apex processes similar frequencies and is thus relevant for the study of speech processing in the cochlea. However, the requirement for extensive surgery has challenged the optical accessibility of this area to investigate cochlear processing of signals without significant intrusion. A simple method is developed to provide optical access to the guinea pig cochlear apex in two directions with minimal surgery. Furthermore, all prior vibration measurements in the guinea pig apex involved opening an observation hole in the otic capsule, which has been questioned on the basis of the resulting changes to cochlear hydrodynamics. Here, this limitation is overcome by measuring the vibrations through the unopened otic capsule using phase-sensitive Fourier domain optical coherence tomography. The optically and surgically advanced method described here lays the foundation to perform minimally invasive investigation of speech-related signal processing in the cochlea.
Melanoma Early Detection: Big Data, Bigger Picture Petrie, Tracy; Samatham, Ravikant; Witkowski, Alexander M. ...
Journal of investigative dermatology,
01/2019, Letnik:
139, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Innovative technologies, including novel communication and imaging tools, are affecting dermatology in profound ways. A burning question for the field is whether we will retrospectively react to ...innovations or proactively leverage them to benefit precision medicine. Early detection of melanoma is a dermatologic area particularly poised to benefit from such innovation. This session of the Montagna Symposium on Biology of Skin focused on provocative, potentially disruptive advances, including crowdsourcing of patient advocacy efforts, rigorous experimental design of public education campaigns, research with mobile phone applications, advanced skin imaging technologies, and the emergence of artificial intelligence as a diagnostic supplement.
Advancements in smartphone technologies and the use of specialized health care applications offer an exciting new era to promote melanoma awareness to the public and improve education and prevention ...strategies. These applications also afford an opportunity to power meaningful research aimed at improving image diagnostics and early melanoma detection. Here, we summarize our experience associated with developing and managing the implementation of MoleMapper™, a research-based application that not only provides an efficient way for users to digitally track images of moles and facilitate skin self-examinations but also provides a platform to crowdsource research participants and the curation of mole images in efforts to advance melanoma research. Obtaining electronic consent, safeguarding participant data, and employing a framework to ensure collection of meaningful data represent a few of the inherent difficulties associated with orchestrating such a wide-scale research enterprise. In this review, we discuss strategies to overcome these and other challenges leading to the implementation of MoleMapper™.
This study investigated whether genetic counseling and test reporting for the highly penetrant CDKN2A melanoma predisposition gene promoted decreases in sun exposure.
A prospective, nonequivalent ...control group design compared unaffected participants (N = 128, M
= 35.24, 52% men) from (1) families known to carry a CDKN2A pathogenic variant, who received counseling about management recommendations and a positive or negative genetic test result and (2) no-test control families known not to carry a CDKN2A pathogenic variant, who received equivalent counseling based on their comparable family history. Changes in daily ultraviolet radiation (UVR) exposure (J/m
), skin pigmentation (melanin index), and sunburns between baseline and one year following counseling were compared among carriers (n = 32), noncarriers (n = 46), and no-test control participants (n = 50).
Both carriers and no-test control participants exhibited a decrease one year later in daily UVR dose (B = -0.52, -0.33, p < 0.01). Only carriers exhibited a significant decrease in skin pigmentation at the wrist one year later (B = -0.11, p < 0.001), and both carriers and no-test control participants reported fewer sunburns than noncarriers (p < 0.05). Facial pigmentation did not change for any group. Noncarriers did not change on any measure of UVR exposure.
These findings support the clinical utility of disclosing CDKN2A test results and providing risk management education to high-risk individuals.
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