1,043 research outputs found

    Physical and geometric constraints explain the labyrinth-like shape of the nasal cavity

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    The nasal cavity is a vital component of the respiratory system that heats and humidifies inhaled air in all vertebrates. Despite this common function, the shapes of nasal cavities vary widely across animals. To understand this variability, we here connect nasal geometry to its function by theoretically studying the airflow and the associated scalar exchange that describes heating and humidification. We find that optimal geometries, which have minimal resistance for a given exchange efficiency, have a constant gap width between their side walls, but their overall shape is restricted only by the geometry of the head. Our theory explains the geometric variations of natural nasal cavities quantitatively and we hypothesize that the trade-off between high exchange efficiency and low resistance to airflow is the main driving force shaping the nasal cavity. Our model further explains why humans, whose nasal cavities evolved to be smaller than expected for their size, become obligate oral breathers in aerobically challenging situations.Comment: 7 pages, 4 figure

    Depth of Field Analysis for Multilayer Automultiscopic Displays

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    With the re-emergence of stereoscopic displays, through polarized glasses for theatrical presentations and shuttered liquid crystal eyewear in the home, automultiscopic displays have received increased attention. Commercial efforts have predominantly focused on parallax barrier and lenticular architectures applied to LCD panels. Such designs suffer from reduced resolution and brightness. Recently, multilayer LCDs have emerged as an alternative supporting full-resolution imagery with enhanced brightness and depth of field. We present a signal-processing framework for comparing the depth of field for conventional automultiscopic displays and emerging architectures comprising multiple light-attenuating layers. We derive upper bounds for the depths of field, indicating the potential of multilayer configurations to significantly enhance resolution and depth of field, relative to conventional designs.Massachusetts Institute of Technology. Media LaboratoryMIT Camera Culture GroupNational Science Foundation (U.S.) (Grant IIS-1116452)United States. Defense Advanced Research Projects Agency. MOSAIC ProgramUnited States. Defense Advanced Research Projects Agency. SCENICC ProgramAlfred P. Sloan Foundation (Research Fellowship)United States. Defense Advanced Research Projects Agency. (Young Faculty Award

    Long term results of postoperative Intensity-Modulated Radiation Therapy (IMRT) in the treatment of Squamous Cell Carcinoma (SCC) located in the oropharynx or oral cavity

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    Background: To report our long-term results with postoperative intensity-modulated radiation therapy (IMRT) in patients suffering from squamous-cell carcinoma (SCC) of the oral cavity or oropharynx. Methods: Seventy five patients were retrospectively analyzed. Median age was 58 years and 84 % were male. 76 % of the primaries were located in the oropharynx. Surgery resulted in negative margins (R0) in 64 % of the patients while 36 % suffered from positive margins (R1). Postoperative stages were as follows: stage1:4 %, stage2:9 %, stage3:17 %, stage4a:69 % with positive nodes in 84 %. Perineural invasion (Pn+) and extracapsular extension (ECE) were present in 7 % and 29 %, respectively. All patients received IMRT using the step-and-shoot approach with a simultaneously integrated boost (SIB) in 84 %. Concurrent systemic therapy was applied to 53 patients, mainly cisplatin weekly. Results: Median follow-up was 55 months (5–150). 13 patients showed locoregional failures (4 isolated local, 4 isolated neck, 5 combined) transferring into 5-year-LRC rates of 85 %. Number of positive lymph nodes (n > 2) and presence of ECE were significantly associated with decreased LRC in univariate analysis, but only the number of nodes remained significant in multivariate analysis. Overall treatment failures occurred in 20 patients (9 locoregional only, 7 distant only, 4 combined), transferring into 3-and 5-year-FFTF rates of 77 % and 75 %, respectively. The 3-and 5-year-OS rates were 80 % and 72 %, respectively. High clinical stage, high N stage, number of positive nodes (n > 2), ECE and Pn1 were significantly associated with worse FFTF and OS in univariate analysis, but only number of nodes remained significant for FFTF in multivariate analysis. Maximum acute toxicity was grade 3 in 64 % and grade 4 in 1 %, mainly hematological or mucositis/dysphagia. Maximum late toxicity was grade 3 in 23 % of the patients, mainly long-term tube feeding dependency. Conclusion: Postoperative IMRT achieved excellent LRC and good OS with acceptable acute and low late toxicity rates. The number of positive nodes (n > 2) was a strong prognostic factor for all endpoints in univariate and the only significant factor for LRC and FFTF in multivariate analysis. Patients with feeding tubes due to postoperative complications had an increased risk for long-term feeding tube dependency

    Intensity modulated or fractionated stereotactic reirradiation in patients with recurrent nasopharyngeal cancer

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    <p>Abstract</p> <p>Purpose</p> <p>To report our experience with intensity-modulated or stereotactic reirradiation in patients suffering from recurrent nasopharyngeal carcinoma</p> <p>Patients and Methods</p> <p>The records of 17 patients with recurrent nasopharygeal carcinoma treated by intensity-modulated (n = 14) or stereotactic (n = 3) reirradiation in our institution were reviewed. Median age was 53 years and most patients (n = 14) were male. The majority of tumors showed undifferentiated histology (n = 14) and infiltration of intracranial structures (n = 12). Simultaneous systemic therapy was applied in 8 patients. Initial treatment covered the gross tumor volume with a median dose of 66 Gy (50-72 Gy) and the cervical nodal regions with a median dose of 56 Gy (50-60 Gy). Reirradiation was confined to the local relapse region with a median dose of 50.4 Gy (36-64Gy), resulting in a median cumulative dose of 112 Gy (91-134 Gy). The median time interval between initial and subsequent treatment was 52 months (6-132).</p> <p>Results</p> <p>The median follow up for the entire cohort was 20 months and 31 months for survivors (10-84). Five patients (29%) developed isolated local recurrences and three patients (18%) suffered from isolated nodal recurrences. The actuarial 1- and 2-year rates of local/locoregional control were 76%/59% and 69%/52%, respectively. Six patients developed distant metastasis during the follow up period. The median actuarial overall survival for the entire cohort was 23 months, transferring into 1-, 2-, and 3-year overall survival rates of 82%, 44% and 37%. Univariate subset analyses showed significantly increased overall survival and local control for patients with less advanced rT stage, retreatment doses > 50 Gy, concurrent systemic treatment and complete response. Severe late toxicity (Grad III) attributable to reirradiation occurred in five patients (29%), particularly as hearing loss, alterations of taste/smell, cranial neuropathy, trismus and xerostomia.</p> <p>Conclusion</p> <p>Reirradiation with intensity-modulated or stereotactic techniques in recurrent nasopharyngeal carcinoma is feasible and yields encouraging results in terms of local control and overall survival in patients with acceptable toxicity in patients with less advanced recurrences. However, the achievable outcome is limited in patients with involvement of intracranial structures, emphasising the need for close monitoring after primary therapy.</p

    Tract-Based Spatial Statistics in Preterm-Born Neonates Predicts Cognitive and Motor Outcomes at 18 Months.

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    BACKGROUND AND PURPOSE: Adverse neurodevelopmental outcome is common in children born preterm. Early sensitive predictors of neurodevelopmental outcome such as MR imaging are needed. Tract-based spatial statistics, a diffusion MR imaging analysis method, performed at term-equivalent age (40 weeks) is a promising predictor of neurodevelopmental outcomes in children born very preterm. We sought to determine the association of tract-based spatial statistics findings before term-equivalent age with neurodevelopmental outcome at 18-months corrected age. MATERIALS AND METHODS: Of 180 neonates (born at 24-32-weeks\u27 gestation) enrolled, 153 had DTI acquired early at 32 weeks\u27 postmenstrual age and 105 had DTI acquired later at 39.6 weeks\u27 postmenstrual age. Voxelwise statistics were calculated by performing tract-based spatial statistics on DTI that was aligned to age-appropriate templates. At 18-month corrected age, 166 neonates underwent neurodevelopmental assessment by using the Bayley Scales of Infant Development, 3rd ed, and the Peabody Developmental Motor Scales, 2nd ed. RESULTS: Tract-based spatial statistics analysis applied to early-acquired scans (postmenstrual age of 30-33 weeks) indicated a limited significant positive association between motor skills and axial diffusivity and radial diffusivity values in the corpus callosum, internal and external/extreme capsules, and midbrain (P \u3c .05, corrected). In contrast, for term scans (postmenstrual age of 37-41 weeks), tract-based spatial statistics analysis showed a significant relationship between both motor and cognitive scores with fractional anisotropy in the corpus callosum and corticospinal tracts (P \u3c .05, corrected). Tract-based spatial statistics in a limited subset of neonates (n = 22) scanned at CONCLUSIONS: The strength of the association between fractional anisotropy values and neurodevelopmental outcome scores increased from early-to-late-acquired scans in preterm-born neonates, consistent with brain dysmaturation in this population

    Fusion In The Era Of Burning Plasma Studies: Workforce Planning For 2004-2014

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    This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Raymond Orbach (Appendix A), asking FESAC to addressed the issue of workforce development in the U.S. fusion program. This report, submitted to FESAC March 29, 2004 and subsequently approved by them (Appendix B), presents FESAC\u27s response to that charge

    Th17 micro-milieu regulates NLRP1-dependent caspase-5 activity in skin autoinflammation.

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    IL-1β is a potent player in cutaneous inflammation and central for the development of a Th17 micro-milieu in autoinflammatory diseases including psoriasis. Its production is controlled at the transcriptional level and by subsequent posttranslational processing via inflammatory caspases. In this study, we detected inflammatory caspase-5 active in epidermal keratinocytes and in psoriatic skin lesions. Further, interferon-γ and interleukin-17A synergistically induced caspase-5 expression in cultured keratinocytes, which was dependent on the antimicrobial peptide psoriasin (S100A7). However, diseases-relevant triggers for caspase-5 activity and IL-1β production remain unknown. Recently, extranuclear DNA has been identified as danger-signals abundant in the psoriatic epidermis. Here, we could demonstrate that cytosolic double-stranded (ds) DNA transfected into keratinocytes triggered the activation of caspase-5 and the release of IL-1β. Further, interleukin-17A promoted caspase-5 function via facilitation of the NLRP1-inflammasome. Anti-inflammatory vitamin D interfered with the IL-1β release and suppressed caspase-5 in keratinocytes and in psoriatic skin lesions. Our data link the disease-intrinsic danger signals psoriasin (S100A7) and dsDNA for NLPR1-dependent caspase-5 activity in psoriasis providing potential therapeutic targets in Th17-mediated skin autoinflammation

    The Pine Needle, May 1947

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    Libraries and archives collect materials from different cultures and time periods to preserve and make available the historical record. As a result, materials such as those presented here may reflect sexist, misogynistic, abusive, racist, or discriminatory attitudes or actions that some may find disturbing, harmful, or difficult to view. Both a humor and literary magazine, The Pine Needle was a University of Maine student-produced periodical that began publication in the fall of 1946, the first post-World War II semester that saw GIs returning to campus. The Needle reflected an edginess and rebellion not found in previous student publications. While past student publications relied on euphemisms for alcohol and dating on campus, The Needle openly promoted the sexualization of co-eds and the use of drugs, tobacco, and alcohol by students who experienced war. In response to Alumni complaints that The Needle was ...filled with sex and drinking, the University Publications Committee instituted stricter controls. In this issue, the editorial staff announce that starting in Fall 1947, the publication would publish only four issues of the magazine each year—Fall, Christmas, Spring, and Graduation among other changes. Cover art for this issue is an unsigned ink illustration of chatting university students lined up outside a shop bearing a sign that reads Jifty Cleaners-Dyers. Signs in the shop window reads We Specialize in Grass Stains. 24 Hour Service

    Investigating Perceptual Congruence Between Data and Display Dimensions in Sonification

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    The relationships between sounds and their perceived meaning and connotations are complex, making auditory perception an important factor to consider when designing sonification systems. Listeners often have a mental model of how a data variable should sound during sonification and this model is not considered in most data:sound mappings. This can lead to mappings that are difficult to use and can cause confusion. To investigate this issue, we conducted a magnitude estimation experiment to map how roughness, noise and pitch relate to the perceived magnitude of stress, error and danger. These parameters were chosen due to previous findings which suggest perceptual congruency between these auditory sensations and conceptual variables. Results from this experiment show that polarity and scaling preference are dependent on the data:sound mapping. This work provides polarity and scaling values that may be directly utilised by sonification designers to improve auditory displays in areas such as accessible and mobile computing, process-monitoring and biofeedback
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