Spectrally-encoded miniature endoscopy uses a single optical fiber and wavelength division multiplexing to obtain macroscopic images through miniature, flexible probes. In turn, it has the potential ...to enable two- and three-dimensional imaging within the body at locations that are currently difficult to access with conventional endoscopes. Here we present a novel detection scheme for spectrally-encoded endoscopy using spectral-domain interferometry. Compared to previous time-domain configurations, this new detection method results in greater than 1000-fold increase in sensitivity (77 dB), a 6-fold increase in imaging speed (30 volumes per second), and a 2-fold increase in depth range (2.8 mm). We demonstrate spectrally-encoded, spectral-domain detection by conducting video-rate, three-dimensional imaging in a variety of specimens, including the paws of a mouse embryo and excised human ear bones. Our results show that this new technology enables video rate spectrally-encoded endoscopy and will therefore be useful for a variety of minimally invasive medical applications.
Although some taxa are increasing in number due to active management and predator control, the overall number of kiwi (Apteryx spp.) is declining. Kiwi are cryptic and rare, meaning current ...monitoring tools, such as call counts, radio telemetry, and surveys using detection dogs are labor‐intensive, yield small datasets, and require substantial resources or provide inaccurate estimates of population sizes. A noninvasive genetic approach could help the conservation effort. We optimized a panel of 23 genetic markers (22 autosomal microsatellite loci and an allosomal marker) to discriminate between all species of kiwi and major lineages within species, while simultaneously determining sex. Markers successfully amplified from both fecal and shed feather DNA samples collected in captivity. We found that DNA extraction was more efficient from shed feathers, but DNA quality was greater with feces, although this was sampling dependent. Our microsatellite panel was able to distinguish between contemporary kiwi populations and lineages and provided PI values in the range of 4.3 × 10−5 to 2.0 × 10−19, which in some cases were sufficient for individualization and mark–recapture studies. As such, we have tested a wide‐reaching, noninvasive molecular approach that will improve conservation management by providing better parameter estimates associated with population ecology and demographics such as abundance, growth rates, and genetic diversity.
We optimized a panel of 23 genetic markers (22 autosomal microsatellite loci and an autosomal marker) to discriminate between all currently recognized taxa of kiwi (Apteryx spp.), while simultaneously determining sex. Markers successfully amplified from both fecal and molted feather DNA and are sufficiently informative to allow individualization inference to be made in some cases. As such, we have developed a wide‐reaching, noninvasive molecular tool that will contribute to kiwi population monitoring (i.e., effective population size changes) and help reverse the overall decline in kiwi numbers while maintaining contemporary genetic variation.
Evaluating the success of endoluminal repair of abdominal aortic aneurysms (AAAs) is frequently based on diameter measurements and determining the presence of endoleaks. The use of three-dimensional ...volumetric data and observation of morphologic changes in the aneurysm and device have been proposed to be more appropriate for postdeployment surveillance. The purpose of this study was to analyze the long-term volumetric and morphologic data of 161 patients who underwent endovascular AAA exclusion and to assess the utility of volume measurements for determining successful AAA repair.
Patients with spiral computed tomography scans obtained preoperatively, within the first postoperative month, at 6 months, and annually thereafter, were included in this analysis. Computerized interactive three-dimensional reconstruction of each AAA scan was performed. Total aneurysm sac volume was measured at each time interval (mean preoperative volume 169.0 ± 78.5 mL), and the significance of volume changes was determined by mixed linear modeling, a form of repeated measures analysis, to account for longitudinal data clustered at the individual level. Sixty-two patients (38%) developed endoleaks at some time during follow-up—15 type I leaks, 45 type II leaks, and 2 type III leaks. The patients with type I and type III leaks were treated with cuffs, and the type II leaks were treated either with observation, side-branch embolization, or required open conversion.
Aneurysm sac volume increased slightly at 1-month follow-up (+3.3%), and then decreased steadily to −12.9% at 5 years (
P < .0001). This effect remained unchanged after controlling for the three device types used in our study population. Patients who did not exhibit an endoleak (n = 99) showed a significant decrease in aneurysm volume across the entire follow-up duration when compared with those who did exhibit an endoleak (n = 62) (
P < .0001). The presence of a 10% or greater decrease in volume at 6 months demonstrated a sensitivity of 64%, a specificity of 95%, a positive predictive value of 95%, a negative predictive value of 62%, and an accuracy of 75% for predicting primary clinical success defined by successful deployment of the device; freedom from aneurysm- or procedure-related death; freedom from endoleak, rupture, migration, or device malfunction; or conversion to open repair.
Volumetric analysis may be used to predict successful endoluminal exclusion of AAAs. Volume regression appears to be device-independent and should be expected in most clinically successful cases. The presence of volume increases in the first 6 months is suspicious for an endoleak that is pressurizing the aneurysm sac and heralds the need for closer evaluation and possible intervention. A volume decrease of 10% or greater at 6 months and continuing regression over time is associated with successful endovascular repair.
The shaft capacity of piles in sand subjected to cyclic (wave) loading has been observed to decrease significantly with loading cycles (Poulos, 1989). A number of researchers (Boulon and Foray, 1986; ...Tabucanon et al., 1995; Shahrour et al., 1999) have replicated the characteristics of the load transfer degradation behavior in the laboratory through cyclic interface shear testing with a constant normal stiffness confinement condition (Vesic, 1972). However, no consensus currently exists as to the primary microscale mechanisms that govern cyclic interface shear behavior and load transfer degradation.
A research program was undertaken to quantify the contribution of soil properties, cementation, confinement condition, and displacement mode, in load transfer degradation. Monotonic and cyclic interface shear tests were performed using a modified interface direct shear device with a Perspex side window. The specimen particle displacement fields were quantified during selected cycles by capturing high resolution digital images (1600 x 1200 pixels) and using Particle Image Velocimetry (White et al., 2001a). Results indicate that the confinement condition, which is intended to replicate the elastic response of the far-field soil, is of primary importance as it allows for normal stress relaxation with soil contraction adjacent to the interface. The displacement magnitude, particle characteristics, and particle-particle cementation were also observed to affect the magnitude and rate of degradation. It is anticipated that these findings will provide a fundamental rationale to identify field conditions where shear stress degradation is likely to occur and a basis from which more rigorous models may be developed.
Statins elicit numerous favorable effects on central nervous system (CNS) injury, including inhibition of the rhoA/ROCK pathway. In the present study, we show that statins decrease acute astrocyte ...activation in CNS injury, and decrease chondroitin sulfate proteoglycan (CSPG) levels in astrocyte cultures as well as CNS injury. CSPG levels decreased by up to 45% in simvastatin-treated astrocyte cultures compared to control cultures. In simvastatin-treated animals, CSPG levels declined by 60% 8 days after brain stab injury, and by 62–64% 4 weeks after spinal cord injury (SCI). Glial fibrillary acid protein (GFAP) levels decreased in brain stab at 8 days after surgery/intervention, suggesting that statins produce a decrease in astrocyte activation. Attenuation of astrocyte activation may contribute to the decline in CSPG levels. However, there are likely other contributing factors, since GFAP levels were not a contributing factor in the decline of CSPG levels in astrocyte cultures. Robust locomotor improvements were not observed with any treatment. The numerous beneficial effects of statins on CNS injury render them an attractive candidate in the treatment of CNS injury.
Previous studies of human and simian immunodeficiency virus (HIV and SIV) have demonstrated that adaptive mutations selected during the course of infection alter viral replicative fitness, ...persistence, and pathogenicity. What is unclear from those studies is the impact of transmission on the replication and pathogenicity of the founding virus population. Using the SIV-macaque model, we examined whether the route of infection would affect the establishment and replication of two SIVmne variants of distinct in vitro and in vivo biological characteristics. For these studies, we performed dual-virus inoculations of pig-tailed macaques via intrarectal or intravenous routes with SIVmneCl8, a minimally pathogenic virus, and SIVmne027, a highly pathogenic variant that replicates more robustly in CD4+ T cells.
The data demonstrate that SIVmne027 is the dominant virus regardless of the route of infection, indicating that the capacity to replicate efficiently in CD4+ T cells is important for fitness. Interestingly, in comparison to intravenous co-infection, intrarectal inoculation enabled greater relative replication of the less pathogenic virus, SIVmneCl8. Moreover, a higher level of SIVmneCl8 replication during primary infection of the intrarectally inoculated macaques was associated with lower overall plasma viral load and slower decline in CD4+ T cells, even though SIVmne027 eventually became the dominant virus.
These results suggest that the capacity to replicate in CD4+ T cells is a significant determinant of SIV fitness and pathogenicity. Furthermore, the data also suggest that mucosal transmission may support early replication of phenotypically diverse variants, while slowing the rate of CD4+ T cell decline during the initial stages of infection.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The concept of catheter-based ultrasound imaging was first introduced in the early 1970s. Since its inception, intravascular ultrasound (IVUS) technology has become more user-friendly because of ...improvements in both the catheters and computer-driven imaging platforms. IVUS catheters enable luminal and transmural cross-sectional imaging of coronary and peripheral blood vessels with high-dimensional accuracy and detailed information about lesion morphology. With the advent of endovascular techniques in both the coronary and peripheral vasculature, IVUS has emerged as a useful and necessary adjunct. In addition to providing diagnostic information, IVUS enables optimal choice of appropriate angioplasty technique, endovascular device guidance, and controlled assessment of the efficacy of interventions. In this review we discuss the design and function of available IVUS catheters, imaging techniques and interpretation, and the present and future clinical utility in peripheral endovascular interventions.
Pulvinar signal intensity decrease on T2-weighted images has been reported in some neurological abnormalities. We aimed to define the normal T2 signal hypointensity pattern present in the pulvinar to ...avoid erroneous radiological interpretation. One hundred and forty-two subjects (54 men and 88 women; age range 9–91 years) with unremarkable brain 3T MR findings were enrolled. MR images were analyzed with regard to signal intensity of the pulvinar relative to the thalamus on fluid attenuated inversion recovery images. Effects of age, gender and hemispheric location on the degree of T2 hypointensity were statistically analyzed. The statistical association was measured between the pattern of signal changes in the pulvinar region and that in the putamen and the globus pallidus. We detected a linear signal decrease in the pulvinar region with age. The male subjects had a more rapid decrease of signal with age than female subjects. The right pulvinar region had a higher chance of hypointensity compared to the left. A positive linear association was found when signal change from the pulvinar region was compared with signal in the putamen and globus pallidus. We detected a linear signal decrease with age in the pulvinar. The physiological signal features of the pulvinar also depend on gender and hemispheric lateralization. The pattern of signal change in the pulvinar is similar to but not the same as that in the putamen and globus pallidus.
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