436 research outputs found
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Process Planning Based on User Preferences
Typical approaches to adaptive slicing in previous literature have typically used surface finish
requirements to control the slicing process. As a result, slice schemes improve the part's surface
quality, but do not enable explicit trade-offs between finish and build time. The purpose of this
article is to present a process planning method that enables the preferences of the user for surface
finish, build time, and accuracy to control how trade-offs are made in a process plan. A multiobjective goal formulation is used by this method to evaluate how well user preferences are met by
a process plan. This method consists of three modules, for determining part orientation, for slicing
the part, and for determining other parameter values. An example with several scenarios
representing different user preferences is provided to illustrate the process planning method.Mechanical Engineerin
NETWORK SERVICE DELIVERY AND THROUGHPUT OPTIMIZATION VIA SOFTWARE DEFINED NETWORKING
In today\u27s world, transmitting data across large bandwidth-delay product (BDP) networks requires special configuration on end users\u27 machines in order to be done efficiently. This added level of complexity creates extra cost and is usually overlooked by users unknowledgeable to the issues. This is one example problem which can be ameliorated with the emerging software defined networking (SDN) paradigm. In an SDN, packet forwarding is controlled via software controllers. In an OpenFlow SDN, a controller can control the forwarding, rewriting, and dropping of packets based on their header attributes. The ability to handle packets in customizable ways in software has significant implications for both users and operators of the network. Via SDN, network providers can easily provide services to enhance users\u27 experience of the network. Steroid OpenFlow Service (SOS) is presented as a solution to seamless enhancement of TCP data transfer throughput over large BDP networks without any modification to the software and configurations on users\u27 machines. SOS utilizes OpenFlow to redirect application specific traffic to application specific service agents. SOS uses service agents on both ends of the connection to seamlessly terminate a user\u27s TCP connection, launch a set of parallel TCP connections, and leverage multiple paths when available to maximize throughput
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A Process Planning Method and Data Format for Achieving Tolerances in Stereolithography
When building parts in a stereolithography apparatus (SLA), the user is faced with many decis!ons
regarding the setting of process variables. To 'achieve a set of tolera~ces as closely as pOSSIble,
relationships between part geometry, tolerances, and process v~nables ~ust be understood
quantitatively. This paper presents a method for SLA process plannIng that IS based on response
surface methodology and multi-objective optimization, where the response surfaces capture these
relationships. These response surfaces were generated by extensive design-of-experiment studies
for a variety of geometries. An annotated STL data format is also presented that enables the
inclusion of tolerance and surface information in fatetted representations. Application of the data
format and process planning method is illustrated on one part.Mechanical Engineerin
Hyperlexia in a 4-year-old boy with Autistic Spectrum Disorder
This paper presents a case study of a 4-year-old boy with Autistic Spectrum Disorder and a mental
age of approximately 1:5 who demonstrates precocious oral-reading behaviour in the absence of
spontaneous speech. Tests of reading regular and irregular words, pseudowords, homographic
heterophones, single sentences and texts were carried out. Performance on a variety of reading tasks
suggests the ability to use grapheme–phoneme correspondences and whole word reading for
decoding single words. In addition, successful reading of some homographic heterophones and
semantic paraphrasing of texts suggests a level of lexical, syntactic, semantic and pragmatic
development far beyond his mental or chronological age. The realisation of highly developed reading
ability is paradoxical in the context of profound impairment in cognitive development and an
absence of spoken language
Loss of BMPR2 Expression in Skeletal Progenitor Cells Reduces Age-Related Bone Loss
Osteoporosis is a disease of low bone mineral density (BMD) that affects 10 million Americans with an additional 34 million at risk for developing the disease. Current FDA-approved therapies for osteoporosis involve anti-resorptive agents but many patients would benefit from augmenting bone formation as well as inhibiting bone loss. We recently reported that targeted deletion of the type 2 BMP receptor BMPR2 using Prx1-Cre in skeletal progenitor cells in mice leads to dramatically increased bone mass and bone formation rate by ten weeks of age in the absence of changes in osteoclast function (Lowery et al 2015). In the present study, we examined the age-related impact of Bmpr2 deletion and found that, consistent with our previous results, both male and female Bmpr2-cKO mice exhibit high bone mass when compared to control mice at 55 weeks of age. We also found that the age-related decline in bone mass from 15 weeks to 55 weeks of age in Bmpr2-cKO mice is reduced approximately three-fold compared to control mice, with male and female Bmpr2-cKO mice losing on average only 18% and 27%, respectively, while male and female control mice lost 55% and 77%, respectively, over the same time span. High bone mass in aged Bmpr2-cKO mice is associated with elevated serum levels of the bone formation marker Procollagen Type I N-terminal Propeptide (P1NP). In contrast, serum levels of the bone resorption marker Collagen Type I C-telopeptide (CTx) are unchanged in Bmpr2-cKO mice. Collectively, these findings indicate that loss of Bmpr2 in skeletal progenitor cells causes a sustained imbalance in bone formation vs. bone resorption and results in high bone mass in the aging skeleton. Our findings suggest that strategies aimed at controlling signaling through BMPR2 have the potential to impact bone mass in the aging adult skeleton
Low sensitivity of the careHPV™ Assay for detection of oncogenic Human papillomavirus in cervical samples from HIV-infected and HIV-uninfected Kenyan women
Background: Human papillomavirus (HPV) infection causes cervical cancer (CC), a common malignancy among Kenyan women. New CC screening methods rely on oncogenic HPV (“highrisk”, or HR-HPV) detection, but most have not been evaluated in swabs from Kenyan women.
Methods: HPV typing was performed on 155 cervical swabs from Kenyan women using the Roche Linear Array® (LA) and careHPV™ (careHPV) assays. Detection of 14 oncogenic HPV types in careHPV assay was compared to LA results.
Results: Compared to LA, sensitivity and specifi city of careHPV assay was 53.0% and 80.9%, respectively. The sensitivity and specifi city of careHPV in swabs from women with cervical dysplasia was 74.1% and 65.2%, respectively. The sensitivity and specifi city of careHPV in swabs from HIV-infected women was 55.9% and of 96.4%, respectively. Overall agreements of careHPV assay with LA was substantial.
Conclusion: The results for careHPV assay are promising for oncogenic HPV detection in Kenyan women. The low sensitivity of careHPV for detection of HR-HPV could limit it’s benefi t as a screening tool. Thus, a full clinical validation study is highly desirable before the careHPV assay can be accepted for cervical cancer screening
Visual Prognosis after Explantation of Small-Aperture Corneal Inlays in Presbyopic Eyes: A Case Series
The purpose of this study was to report visual prognosis after explantation of a small-aperture corneal inlay used for the treatment of presbyopia. This is a retrospective case series conducted at a single site in Draper, Utah, USA (Hoopes Vision). Medical records of 176 patients who had received a small-aperture corneal inlay (KAMRA™, AcuFocus Inc., Irvine, CA, USA) were reviewed. Patients who had undergone explantation of the device were identified. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), and manifest refraction spherical equivalent (MRSE) were measured pre-implantation, post-implantation, pre-explantation, and post-explantation of the inlay. Ten eyes from ten patients were included in this study. The explantation rate was 5.7% over 31 months, with blurry vision as the most common complaint. After explantation, six patients achieved pre-implantation UDVA, and six achieved pre-implantation UNVA. Eight of nine patients who underwent final manifest refraction achieved pre-operative CDVA. All patients had residual donut-shaped corneal haze in the stroma at the previous position of the inlay. All patients experienced improvement in haze with 20% experiencing complete resolution. The degree of stromal haze was not related to the duration of implantation. Of the subset of patients who underwent explantation of their small-aperture corneal inlay, there was persistent loss of CDVA in 10%. The majority of patients experienced some level of residual stromal haze, which may contribute to deficits in UNVA and CDVA in few patients. A hyperopic shift induced by the corneal inlay may contribute to the blurry vision these patients experienced; there was a reduction of this shift post-explantation. While this device is removable, patients should expect some post-explantation changes such as residual haze with a small subset experiencing persistent deficits in CDVA
Near-unity nuclear polarization with an open-source 129Xe hyperpolarizer for NMR and MRI
The exquisite NMR spectral sensitivity and negligible reactivity of hyperpolarized xenon-129 (HP129Xe) make it attractive for a number of magnetic resonance applications; moreover, HP129Xe embodies an alternative to rare and nonrenewable 3He. However, the ability to reliably and inexpensively produce large quantities of HP129Xe with sufficiently high 129Xe nuclear spin polarization (PXe) remains a significant challenge—particularly at high Xe densities. We present results from our “open-source” large-scale (∼1 L/h) 129Xe polarizer for clinical, preclinical, and materials NMR and MRI research. Automated and composed mostly of off-the-shelf components, this “hyperpolarizer” is designed to be readily implementable in other laboratories. The device runs with high resonant photon flux (up to 200 W at the Rb D1 line) in the xenon-rich regime (up to 1,800 torr Xe in 500 cc) in either single-batch or stopped-flow mode, negating in part the usual requirement of Xe cryocollection. Excellent agreement is observed among four independent methods used to measure spin polarization. In-cell PXe values of ∼90%, ∼57%, ∼50%, and ∼30% have been measured for Xe loadings of ∼300, ∼500, ∼760, and ∼1,570 torr, respectively. PXe values of ∼41% and ∼28% (with ∼760 and ∼1,545 torr Xe loadings) have been measured after transfer to Tedlar bags and transport to a clinical 3 T scanner for MR imaging, including demonstration of lung MRI with a healthy human subject. Long “in-bag” 129Xe polarization decay times have been measured (T1 ∼38 min and ∼5.9 h at ∼1.5 mT and 3 T, respectively)—more than sufficient for a variety of applications
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