621 research outputs found
Anatomy of the transmastoid endolymphatic sac decompression in the management of Ménière’s disease.
Ménière’s disease affects 1 in 1000 people and produces vertigo and hearing loss (Morrison, 1981). Endolymphatic sac decompression has been advocated on the basis that endolymphatic hydrops is the underlying pathology. The endolymphatic sac is said to be the terminal dilatation of the membranous labyrinth. It has been proposed that endolymph flows from the semicircular canals and cochlea to the endolymphatic sac. Portman (1927) devised a procedure for ‘decompressing’ the endolymphatic sac by removal of the bone from the posterior cranial fossa to relieve the symptoms of Ménière’s disease. Surgery on the endolymphatic sac remains controversial.
Shea (1979) and Bagger-Sjöbäck et al (1990, 1993) have studied the endolymphatic sac using different techniques. There are discrepancies in the results between the two studies.
The hypothesis that the endolymphatic sac can be safely approached and decompressed by a transmastoid route was tested. A total of thirteen cadaver heads and ten isolated temporal bones were used. A series of dissections were performed to examine the endolymphatic sac, perform measurements and analyse surgical approaches to the sac. Histological and electron microscopic study were performed.
The lumen of the endolymphatic sac was not always identifiable in the dura of the posterior cranial fossa or it frequently lay over the sigmoid sinus. In the dura of the posterior cranial fossa where the endolymphatic sac is located was a thickening of the dura. This thickening was present even in the absence of the endolymphatic sac. The endolymphatic sac can be safely approached by a transmastoid approach, if there is an extraosseous component to the endolymphatic sac. The proximal endolymphatic sac can be approached by posterior cranial fossa route
The very large G-protein coupled receptor VLGR1: a component of the ankle link complex required for the normal development of auditory hair bundles
Sensory hair bundles in the inner ear are composed of stereocilia that can be interconnected by a variety of different link types, including tip links, horizontal top connectors, shaft connectors, and ankle links. The ankle link antigen is an epitope specifically associated with ankle links and the calycal processes of photoreceptors in chicks. Mass spectrometry and immunoblotting were used to identify this antigen as the avian ortholog of the very large G-protein-coupled receptor VLGR1, the product of the Usher syndrome USH2C (Mass1) locus. Like ankle links, Vlgr1 is expressed transiently around the base of developing hair bundles in mice. Ankle links fail to form in the cochleae of mice carrying a targeted mutation in Vlgr1 (Vlgr1/del7TM), and the bundles become disorganized just after birth. FM1-43 [N-(3-triethylammonium)propyl)-4-(4-(dibutylamino)styryl) pyridinium dibromide] dye loading and whole-cell recordings indicate mechanotransduction is impaired in cochlear, but not vestibular, hair cells of early postnatal Vlgr1/del7TM mutant mice. Auditory brainstem recordings and distortion product measurements indicate that these mice are severely deaf by the third week of life. Hair cells from the basal half of the cochlea are lost in 2-month-old Vlgr1/del7TM mice, and retinal function is mildly abnormal in aged mutants. Our results indicate that Vlgr1 is required for formation of the ankle link complex and the normal development of cochlear hair bundles
The Promise and Perils of Private Voluntary Regulation: Labor Standards and Work Organization in Two Mexican Garment Factories
This paper is part of a larger project on globalization and labor standards organized by Professor Richard
Locke of M.I.T.. In addition to the results presented in this paper (some of which appear as well in Monica Romis,
"Beneath Corporate Codes of Conduct: What Drives Compliance in Two Mexican Garment Factories," (Masters
Thesis, Dept. of Urban Studies and Planning, M.I.T., 2005)), the project entailed field research in China, Turkey, Europe and the United States as well as systematic analysis of Nike’s factory audits of working conditions in over 800 factories in 51 countries.What role can private voluntary regulation play in improving labor standards and working conditions in global supply chain factories? How does this system relate to and interact with other systems of labor regulation and work organization? This paper seeks to address these questions through a structured comparison of two factories supplying Nike, the world’s largest athletic footwear and apparel company. These two factories have many similarities - both are in Mexico, both are in the apparel industry, both produce more or less the same products for Nike (and other brands) and both are subject to the same code of conduct. On the surface, both factories appear to have similar employment (i.e., recruitment, training, remuneration) practices and they receive comparable scores when audited by Nike’s compliance staff. However, underlying (and somewhat obscured by) these apparent similarities, significant differences in actual labor conditions exist between these two factories. What drives these differences in working conditions? What does this imply for traditional systems of monitoring and codes of conduct? Field research conducted at these two factories reveals that beneath the code of conduct and various monitoring efforts aimed at enforcing it, workplace conditions and labor standards are shaped by very different patterns of work organization and human resource management policies
Who am I? Autobiographical retrieval improves access to self-concepts
It is considered that an individual's current self-concept plays a crucial role in guiding the retrieval of autobiographical memory. Using a novel fluency paradigm, the present research examined whether or not the reverse is also true, that is, does memory retrieval influence the description of the conceptual self? Specifically, this study examined the effect of prior autobiographical reverie on the subsequent retrieval of stored self-concepts. Participants wrote a description of a personally relevant memory or a control topic (of no relevance to the self), following which they had 60 seconds to generate as many self-defining statements as possible, each beginning with I am. Participants engaging in autobiographical retrieval generated significantly more statements than those in the control condition, suggesting that autobiographical retrieval increased access to self-concepts. Type of statement also varied according to group. Participants in the autobiographical memory condition were more likely to conceptualise themselves in relation to their psychological traits, and this was replicated in a second experiment conducted online. Findings support the idea that self and episodic memory are highly related constructs, and are discussed in relation to implications for individuals with autobiographical memory deficits
Pilot study of impact of a pedal desk on postprandial responses in sedentary workers
Physical inactivity has been linked to rates of obesity, diabetes, and heart disease through insulin resistance and other mechanisms. Although sedentary workplace environments have unintentionally contributed to the risk for chronic diseases, innovations in the workplace environment could potentially rectify this public and occupational health problem. Purpose: To evaluate the effects of light-intensity physical activity using a pedal desk (PD) compared with a standard desk (STD) in a pilot study on postprandial metabolic responses and work skills. Methods: Twelve overweight/obese full-time sedentary office workers (six men and six women; body mass index, 28.7 +/- 3.6 kg m-2) were tested in two conditions: 1) PD, pedaling at self-selected light-intensity pace for 2 h and 2) STD, remaining seated for 2 h in a conventional workstation setup while performing scripted computer-based work tasks. Blood samples were analyzed for plasma glucose, insulin, and free-fatty acids in response to a standardized meal and work skills were evaluated. Paired samples t-tests were used to examine the differences in metabolic responses and work performance tasks between the conditions. Results: Pedal desk use required significantly less insulin to maintain glucose concentrations compared with STD condition (peak insulin concentration, 42.1 uU mL-1 vs 66.9 uU mL-1; P = 0.03; and area under the curve, 302.6 vs 441.8 uU min-1 mL-1; P 0.05). In addition, pedaling at a self-paced rate caused no adverse effects on work skills (P > 0.05). Conclusions: The PD resulted in lower postmeal insulin concentrations without an overall negative impact on work skills. Thus, the PD could have the potential to achieve public and occupational health goals in sedentary work environments.Peer reviewedCommunity Health Sciences, Counseling and Counseling Psycholog
Recollection of childhood abdominal pain in adults with functional gastrointestinal disorders
It is hypothesized that adults who can recall abdominal pain as children are at risk of experiencing a functional gastrointestinal disorder (FGID), but this is not specific to any particular FGID. The aim of this study was to evaluate the association between recollecting abdominal pain as a child and experiencing a FGID
The narrative self, distributed memory, and evocative objects
In this article, I outline various ways in which artifacts are interwoven with autobiographical memory systems and conceptualize what this implies for the self. I first sketch the narrative approach to the self, arguing that who we are as persons is essentially our (unfolding) life story, which, in turn, determines our present beliefs and desires, but also directs our future goals and actions. I then argue that our autobiographical memory is partly anchored in our embodied interactions with an ecology of artifacts in our environment. Lifelogs, photos, videos, journals, diaries, souvenirs, jewelry, books, works of art, and many other meaningful objects trigger and sometimes constitute emotionally-laden autobiographical memories. Autobiographical memory is thus distributed across embodied agents and various environmental structures. To defend this claim, I draw on and integrate distributed cognition theory and empirical research in human-technology interaction. Based on this, I conclude that the self is neither defined by psychological states realized by the brain nor by biological states realized by the organism, but should be seen as a distributed and relational construct
Validation of an integrated pedal desk and electronic behavior tracking platform
Background This study tested the validity of revolutions per minute (RPM) measurements from the Pennington Pedal Desk™. Forty-four participants (73 % female; 39 ± 11.4 years-old; BMI 25.8 ± 5.5 kg/m2 [mean ± SD]) completed a standardized trial consisting of guided computer tasks while using a pedal desk for approximately 20 min. Measures of RPM were concurrently collected by the pedal desk and the Garmin Vector power meter. After establishing the validity of RPM measurements with the Garmin Vector, we performed equivalence tests, quantified mean absolute percent error (MAPE), and constructed Bland–Altman plots to assess agreement between RPM measures from the pedal desk and the Garmin Vector (criterion) at the minute-by-minute and trial level (i.e., over the approximate 20 min trial period). Results The average (mean ± SD) duration of the pedal desk trial was 20.5 ± 2.5 min. Measures of RPM (mean ± SE) at the minute-by-minute (Garmin Vector: 54.8 ± 0.4 RPM; pedal desk: 55.8 ± 0.4 RPM) and trial level (Garmin Vector: 55.0 ± 1.7 RPM; pedal desk: 56.0 ± 1.7 RPM) were deemed equivalent. MAPE values for RPM measured by the pedal desk were small (minute-by-minute: 2.1 ± 0.1 %; trial: 1.8 ± 0.1 %) and no systematic relationships in error variance were evident by Bland–Altman plots. Conclusion The Pennington Pedal Desk™ provides a valid count of RPM, providing an accurate metric to promote usage
Novel venom gene discovery in the platypus
Background: To date, few peptides in the complex mixture of platypus venom have been identified and sequenced, in part due to the limited amounts of platypus venom available to study. We have constructed and sequenced a cDNA library from an active platypus venom gland to identify the remaining components.Results: We identified 83 novel putative platypus venom genes from 13 toxin families, which are homologous to known toxins from a wide range of vertebrates (fish, reptiles, insectivores) and invertebrates (spiders, sea anemones, starfish). A number of these are expressed in tissues other than the venom gland, and at least three of these families (those with homology to toxins from distant invertebrates) may play non-toxin roles. Thus, further functional testing is required to confirm venom activity. However, the presence of similar putative toxins in such widely divergent species provides further evidence for the hypothesis that there are certain protein families that are selected preferentially during evolution to become venom peptides. We have also used homology with known proteins to speculate on the contributions of each venom component to the symptoms of platypus envenomation.Conclusions: This study represents a step towards fully characterizing the first mammal venom transcriptome. We have found similarities between putative platypus toxins and those of a number of unrelated species, providing insight into the evolution of mammalian venom
A vertebrate case study of the quality of assemblies derived from next-generation sequences
The unparalleled efficiency of next-generation sequencing (NGS) has prompted widespread adoption, but significant problems remain in the use of NGS data for whole genome assembly. We explore the advantages and disadvantages of chicken genome assemblies generated using a variety of sequencing and assembly methodologies. NGS assemblies are equivalent in some ways to a Sanger-based assembly yet deficient in others. Nonetheless, these assemblies are sufficient for the identification of the majority of genes and can reveal novel sequences when compared to existing assembly references
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