544 research outputs found
Evaluation of the pharmacodynamic and pharmacokinetic interaction between pagoclone and ethanol
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109936/1/cptclpt2003353.pd
MRI-based Surgical Planning for Lumbar Spinal Stenosis
The most common reason for spinal surgery in elderly patients is lumbar
spinal stenosis(LSS). For LSS, treatment decisions based on clinical and
radiological information as well as personal experience of the surgeon shows
large variance. Thus a standardized support system is of high value for a more
objective and reproducible decision. In this work, we develop an automated
algorithm to localize the stenosis causing the symptoms of the patient in
magnetic resonance imaging (MRI). With 22 MRI features of each of five spinal
levels of 321 patients, we show it is possible to predict the location of
lesion triggering the symptoms. To support this hypothesis, we conduct an
automated analysis of labeled and unlabeled MRI scans extracted from 788
patients. We confirm quantitatively the importance of radiological information
and provide an algorithmic pipeline for working with raw MRI scans
Reliability of the multipegâą transducer in measuring dental implant stability by using a resonance frequency analysis device (OsstellÂź): An observational clinical study
Background: Measuring implant stability is an important issue in predicting treatment success. Dental implant stability is usually measured through resonance frequency analysis (RFA). OsstellÂź RFA devices can be used with transducers (Smartpegâą) that correspond to the implants used as well as with transducers designed for application with PenguinÂź RFA devices (Multipegâą). Aims: This study aims to assess the reliability of a MultiPegâą transducer with an OsstellÂź device in measuring dental implant stability. Materials and Methods: Sixteen healthy participants who required dental implant treatment were enrolled in this study. Implant stability was measured by using an OsstellÂź device with two transducers, namely, Smartpegâą and Multipegâą. Insertion torque was also measured and recorded as >50 and â€50 N·cm. Unpaired t-test and MannâWhitney U test were conducted to assess the relationships of the implant stability values obtained by the two transducers with insertion torque, whereas Pearson and Spearman's correlations were utilized to investigate correlations between the two transducers. Interclass correlation coefficients were applied to assess the reliability between the two transducers. Results: Implant stability measurements (primary and secondary) showed strong positive correlations between Smartpegâą and Multipegâą. The reliability values between both transducers in primary and secondary implant stability measurements were 0.922 and 0.981, respectively. The use of both transducers revealed higher implant stability measurements for implants inserted with insertion torque > 50 N·cm than those inserted with insertion torque †50 N·cm. Conclusions: This study demonstrated that the Multipegâą transducer is reliable in measuring the stability of dental implants using an OsstellÂź device. Â
Uterine selection of human embryos at implantation
Human embryos frequently harbor large-scale complex chromosomal errors that impede normal development. Affected embryos may fail to implant although many first breach the endometrial epithelium and embed in the decidualizing stroma before being rejected via mechanisms that are poorly understood. Here we show that developmentally impaired human embryos elicit an endoplasmic stress response in human decidual cells. A stress response was also evident upon in vivo exposure of mouse uteri to culture medium conditioned by low-quality human embryos. By contrast, signals emanating from developmentally competent embryos activated a focused gene network enriched in metabolic enzymes and implantation factors. We further show that trypsin, a serine protease released by pre-implantation embryos, elicits Ca2+ signaling in endometrial epithelial cells. Competent human embryos triggered short-lived oscillatory Ca2+ fluxes whereas low-quality embryos caused a heightened and prolonged Ca2+ response. Thus, distinct positive and negative mechanisms contribute to active selection of human embryos at implantation
The Self Model and the Conception of Biological Identity in Immunology
The self/non-self model, first proposed by F.M. Burnet, has dominated immunology for sixty years now. According to this model, any foreign element will trigger an immune reaction in an organism, whereas endogenous elements will not, in normal circumstances, induce an immune reaction. In this paper we show that the self/non-self model is no longer an appropriate explanation of experimental data in immunology, and that this inadequacy may be rooted in an excessively strong metaphysical conception of biological identity. We suggest that another hypothesis, one based on the notion of continuity, gives a better account of immune phenomena. Finally, we underscore the mapping between this metaphysical deflation from self to continuity in immunology and the philosophical debate between substantialism and empiricism about identity
Microguards and micromessengers of the genome
The regulation of gene expression is of fundamental importance to maintain organismal function and integrity and requires a multifaceted and highly ordered sequence of events. The cyclic nature of gene expression is known as âtranscription dynamicsâ. Disruption or perturbation of these dynamics can result in significant fitness costs arising from genome instability, accelerated ageing and disease. We review recent research that supports the idea that an important new role for small RNAs, particularly microRNAs (miRNAs), is in protecting the genome against short-term transcriptional fluctuations, in a process we term âmicroguardingâ. An additional emerging role for miRNAs is as âmicromessengersââthrough alteration of gene expression in target cells to which they are trafficked within microvesicles. We describe the scant but emerging evidence that miRNAs can be moved between different cells, individuals and even species, to exert biologically significant responses. With these two new roles, miRNAs have the potential to protect against deleterious gene expression variation from perturbation and to themselves perturb the expression of genes in target cells. These interactions between cells will frequently be subject to conflicts of interest when they occur between unrelated cells that lack a coincidence of fitness interests. Hence, there is the potential for miRNAs to represent both a means to resolve conflicts of interest, as well as instigate them. We conclude by exploring this conflict hypothesis, by describing some of the initial evidence consistent with it and proposing new ideas for future research into this exciting topic
Language vs individuals in cross-linguistic corpus typology
Published as a special publication of Language Documentation & Conservation (No. 25).Peer reviewe
Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - I. Source catalogue and number counts
[Abridged] We present the first results from a 1.1 mm confusion-limited map
of the GOODS-S field taken with AzTEC on the ASTE telescope. We imaged a 270
sq. arcmin field to a 1\sigma depth of 0.48 - 0.73 mJy/beam, making this one of
the deepest blank-field surveys at mm-wavelengths ever achieved. Although our
GOODS-S map is extremely confused, we demonstrate that our source
identification and number counts analyses are robust, and the techniques
discussed in this paper are relevant for other deeply confused surveys. We find
a total of 41 dusty starburst galaxies with S/N >= 3.5 within this uniformly
covered region, where only two are expected to be false detections. We derive
the 1.1mm number counts from this field using both a "P(d)" analysis and a
semi-Bayesian technique, and find that both methods give consistent results.
Our data are well-fit by a Schechter function model with (S', N(3mJy), \alpha)
= (1.30+0.19 mJy, 160+27 (mJy/deg^2)^(-1), -2.0). Given the depth of this
survey, we put the first tight constraints on the 1.1 mm number counts at
S(1.1mm) = 0.5 mJy, and we find evidence that the faint-end of the number
counts at S(850\mu m) < 2.0 mJy from various SCUBA surveys towards lensing
clusters are biased high. In contrast to the 870 \mu m survey of this field
with the LABOCA camera, we find no apparent under-density of sources compared
to previous surveys at 1.1 mm. Additionally, we find a significant number of
SMGs not identified in the LABOCA catalogue. We find that in contrast to
observations at wavelengths < 500 \mu m, MIPS 24 \mu m sources do not resolve
the total energy density in the cosmic infrared background at 1.1 mm,
demonstrating that a population of z > 3 dust-obscured galaxies that are
unaccounted for at these shorter wavelengths potentially contribute to a large
fraction (~2/3) of the infrared background at 1.1 mm.Comment: 21 pages, 9 figures. Accepted to MNRAS
The evolution of genomic imprinting:Theories, predictions and empirical tests
The epigenetic phenomenon of genomic imprinting has motivated the development of numerous theories for its evolutionary origins and genomic distribution. In this review, we examine the three theories that have best withstood theoretical and empirical scrutiny. These are: Haig and colleaguesâ kinship theory; Day and Bondurianskyâs sexual antagonism theory; and Wolf and Hagerâs maternalâoffspring coadaptation theory. These theories have fundamentally different perspectives on the adaptive significance of imprinting. The kinship theory views imprinting as a mechanism to change gene dosage, with imprinting evolving because of the differential effect that gene dosage has on the fitness of matrilineal and patrilineal relatives. The sexual antagonism and maternalâoffspring coadaptation theories view genomic imprinting as a mechanism to modify the resemblance of an individual to its two parents, with imprinting evolving to increase the probability of expressing the fitter of the two alleles at a locus. In an effort to stimulate further empirical work on the topic, we carefully detail the logic and assumptions of all three theories, clarify the specific predictions of each and suggest tests to discriminate between these alternative theories for why particular genes are imprinted
- âŠ