135 research outputs found
Spatiotemporal coupled-mode equations for arbitrary pulse transformation
Spatiotemporal modulation offers a variety of opportunities for light
manipulations. In this paper, we propose a way towards arbitrary transformation
for pulses sequentially propagating within one waveguide in space via temporal
waveguide coupling. The temporal waveguide coupling operation is achieved by
spatiotemporally modulating the refractive index of the spatial waveguide with
a traveling wave through segmented electrodes. We derive the temporal
coupled-mode equations and discuss how systematic parameters affect the
temporal coupling coefficients. We further demonstrated a temporal Mach-Zehnder
interferometer and universal multiport interferometer, which enables arbitrary
unitary transformation for pulses. We showcase a universal approach for
transforming pulses among coupled temporal waveguides, which requires only one
spatial waveguide under spatiotemporal modulation, and hence provide a
flexible, compact, and highly compatible method for optical signal processing
in time domain
Ex vivo mono-ring technique simplifies culotte stenting for treatment of true bifurcation lesions: Insights from bench testing and clinical application
Background: Despite various culotte-based stenting techniques available clinically, the optimal one remains undetermined. The study aimed to test whether ex vivo mono-ring culotte stenting (MRC) was technically feasible and superior to mini culotte stenting (MCS) in treatment of coronary bifurcation lesions.Methods: Mono-ring culotte stenting was characterized by ex vivo wiring of the most proximal cell of the side branch (SB) stent to ensure a mono-ring result of the culotte stenting. Comparison of MRC vs. MCS in treatment of true bifurcation lesions was performed in vitro (n = 15 for each group) and in clinical case-controlled study with propensity matching at a ratio of 1:2 (n = 21 for MRC group; n = 42 for MCS group).Results: Compared to MCS, MRC had lower incidence of stent under-expansion band (0% vs. 53.3%, p = 0.002) and less residual ostial area stenosis of SB (9.2 ± 9.0% vs. 20.0 ± 14.8%, p = 0.023), as assessed in vitro by micro-computed tomography. In a case-controlled study, no adverse cardiac events were observed in the MRC group. The procedural success was similar between MRC and MCS (100% vs. 95.2%, p = 0.548), but MRC had less residual ostial stenosis of the SB (8.7% ± 11.0% vs. 16.8% ± 11.2%, p = 0.008), lower procedural(33.3 ± 9.5 min vs. 46.7 ± 15.6 min, p = 0.001) and fluoroscopic (19.7 ± 4.9 min vs. 26.2 ± 7.1 min, p < 0.001) time, and less contrast use (114.3 ± 28.9 mL vs. 156.5 ± 56.4 mL, p = 0.002).Conclusions: Mono-ring culotte stenting as compared to MCS is associated with better bifurcation stent morphology,less procedural complexity and residual ostial SB stenosis
The regulatory role of APE1 in epithelial-to-mesenchymal transition and in determining EGFR-TKI responsiveness in non-small-cell lung cancer
Dynamic Behaviors of FAâGGBSâHMNS Based Geopolymer Paste When Subjected to Impact Compressive Loadings
Feasibility Study of Dual Energy Radiographic Imaging for Target Localization in Radiotherapy for Lung Tumors
Purpose
Dual-energy (DE) radiographic imaging improves tissue discrimination by separating soft from hard tissues in the acquired images. This study was to establish a mathematic model of DE imaging based on intrinsic properties of tissues and quantitatively evaluate the feasibility of applying the DE imaging technique to tumor localization in radiotherapy.
Methods
We investigated the dependence of DE image quality on the radiological equivalent path length (EPL) of tissues with two phantoms using a stereoscopic x-ray imaging unit. 10 lung cancer patients who underwent radiotherapy each with gold markers implanted in the tumor were enrolled in the study approved by the hospital's Ethics Committee. The displacements of the centroids of the delineated gross tumor volumes (GTVs) in the digitally reconstructed radiograph (DRR) and in the bone-canceled DE image were compared with the averaged displacements of the centroids of gold markers to evaluate the feasibility of using DE imaging for tumor localization.
Results
The results of the phantom study indicated that the contrast-to-noise ratio (CNR) was linearly dependent on the difference of EPL and a mathematical model was established. The objects and backgrounds corresponding to ĂâEPL less than 0.08 are visually indistinguishable in the bone-canceled DE image. The analysis of patient data showed that the tumor contrast in the bone-canceled images was improved significantly as compared with that in the original radiographic images and the accuracy of tumor localization using the DE imaging technique was comparable with that of using fiducial makers.
Conclusion
It is feasible to apply the technique for tumor localization in radiotherapy
Synthesis and magnetic properties of nanocomposite Ni1âx Co x Fe2O4âBaTiO3 fibers by organic gel-thermal decomposition process
Behavioral adaptation of sympatric rodents to early germination of oak acorns: radicle pruning and embryo excision
The seed germination schedule is a key factor affecting the food-hoarding behavior of animals and the seedling regeneration of plants. However, little is known about the behavioral adaptation of rodents to the rapid germination of acorns. In this study, we provided Quercus variabilis acorns to several rodent species to investigate how food-hoarding animals respond to seed germination. We found that only Apodemus peninsulae adopted embryo excision behavior to counteract seed germination, which is the first report of embryo excision in nonsquirrel rodents. We speculated that this species may be at an early stage of the evolutionary response to seed perishability in rodents, given the low rate of embryo excision in this species. On the contrary, all rodent species preferred to prune the radicles of germinating acorns before caching, suggesting that radicle pruning is a stable and more general foraging behavior strategy for food-hoarding rodents. Furthermore, scatter-hoarding rodents preferred to scatter-hoard and prune more germinating acorns, whereas they consumed more nongerminating acorns. Acorns with embryos excised rather than radicles pruned were much less likely to germinate than intact acorns, suggesting a behavioral adaptation strategy by rodents to the rapid germination of recalcitrant seeds. This study provides insight into the impact of early seed germination on plantâanimal interactions
Incorporating cache management behavior into seed dispersal: the effect of pericarp removal on acorn germination.
Selecting seeds for long-term storage is a key factor for food hoarding animals. Siberian chipmunks (Tamias sibiricus) remove the pericarp and scatter hoard sound acorns of Quercus mongolica over those that are insect-infested to maximize returns from caches. We have no knowledge of whether these chipmunks remove the pericarp from acorns of other species of oaks and if this behavior benefits seedling establishment. In this study, we tested whether Siberian chipmunks engage in this behavior with acorns of three other Chinese oak species, Q. variabilis, Q. aliena and Q. serrata var. brevipetiolata, and how the dispersal and germination of these acorns are affected. Our results show that when chipmunks were provided with sound and infested acorns of Quercus variabilis, Q. aliena and Q. serrata var. brevipetiolata, the two types were equally harvested and dispersed. This preference suggests that Siberian chipmunks are incapable of distinguishing between sound and insect-infested acorns. However, Siberian chipmunks removed the pericarp from acorns of these three oak species prior to dispersing and caching them. Consequently, significantly more sound acorns were scatter hoarded and more infested acorns were immediately consumed. Additionally, indoor germination experiments showed that pericarp removal by chipmunks promoted acorn germination while artificial removal showed no significant effect. Our results show that pericarp removal allows Siberian chipmunks to effectively discriminate against insect-infested acorns and may represent an adaptive behavior for cache management. Because of the germination patterns of pericarp-removed acorns, we argue that the foraging behavior of Siberian chipmunks could have potential impacts on the dispersal and germination of acorns from various oak species
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