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OBJECTIVES/GOALS: A negative circumferential resection margin (CRM) after surgical resection of rectal cancer decreases local recurrence and increases overall survival. While MRI is used to predict this risk, there is no predictive model that incorporates clinical factors to predict the risk of CRM positivity. METHODS/STUDY POPULATION: Utilizing the National Cancer Database from 2010-2014, we performed a retrospective study evaluating factors predictive for positive CRM after surgical resection of rectal cancer. The primary outcome was positive CRM (tumorâ‰¤1 mm from the surgical margin). Our population included patients with clinical stage I-III rectal cancer who underwent total mesorectal excision. For the primary outcome, multivariable logistic models were used to estimate the probability of a positive CRM. Model performance was evaluated by using the area under the receiver operating characteristic curve (AUC). Model calibration was assessed by examining the calibration plot. Bootstrapping method (300-iteration) was used to internally validate and estimate optimism-adjusted measures of discrimination and overall model fit. RESULTS/ANTICIPATED RESULTS: There were 28,790 patients included. 2,245 (7.8%) had positive CRM. Older age, race, larger tumor size, higher tumor grade, mucinous and signet tumor histology, APR, open operative approach, facility location, higher T stage, lymphovascular invasion, lack of neoadjuvant chemotherapy/radiation, and perineural invasion were all significantly associated with positive CRM (p DISCUSSION/SIGNIFICANCE: An objective model that predicts positive CRM and associated poor clinical outcomes is possible to be used in conjunction with MRI. Positive CRM is associated with specific patient demographics, tumor characteristics, and operative approach. These factors can be used to predict CRM positivity in the preoperative period and plan accordingly.
We investigate the submerged collapse of weakly polydisperse, loosely packed cohesive granular columns, as a function of aspect ratio and cohesive force strength, via grain-resolving direct numerical simulations. The cohesive forces act to prevent the detachment of individual particles from the main body of the collapsing column, reduce its front velocity, and yield a shorter and thicker final deposit. All of these effects can be captured accurately across a broad range of parameters by piecewise power-law relationships. The cohesive forces reduce significantly the amount of available potential energy released by the particles. For shallow columns, the particle and fluid kinetic energy decreases for stronger cohesion. For tall columns, on the other hand, moderate cohesive forces increase the maximum particle kinetic energy, since they accelerate the initial free-fall of the upper column section. Only for larger cohesive forces does the peak kinetic energy of the particles decrease. Computational particle tracking indicates that the cohesive forces reduce the mixing of particles within the collapsing column, and it identifies the regions of origin of those particles that travel the farthest. The simulations demonstrate that cohesion promotes aggregation and the formation of aggregates. Furthermore, they provide complete information on the temporally and spatially evolving network of cohesive and direct contact force bonds. While the normal contact forces are aligned primarily in the vertical direction, the cohesive bonds adjust their preferred spatial orientation throughout the collapse. They result in a net macroscopic stress that counteracts deformation and slows the spreading of the advancing particle front.
In this paper, we innovatively conduct a Porro prism-based beam pointing stability promotion technique research and realize a high-performance rod-type photonic crystal fiber-based chirped pulse amplification (CPA) system, mainly including a frequency-reduced all-fiber pre-amplification stage, photonic crystal rod-based main amplification stage, and 1600 lines/mm transmission grating-pair compressor. Laser output with average power of 50 W, repetition rates of 500 kHz, pulse energy of 100 μJ, pulse duration of 830 fs, beam quality of M2<1.3, power fluctuation of 0.55% root mean square, and beam pointing drift of 19 μrad/°C over 8 h is realized. The high-performance laser system has an enormous application potential in fundamental research and precision manufacturing fields.
Parabronema skrjabini is one of the most harmful nematodes to camels and is responsible for economic losses in animal husbandry industry. There is an urgent need for in-depth studies of potential vectors of the nematode due to its scant regarding information. As previous studies indicated that flies may be the vectors of P. skrjabini, we captured flies in the main camel-producing areas of Inner Mongolia. After autopsy of the specimens of two species of horn flies, we observed the morphology of the suspected nematode larvae found in them. Internal transcribed spacer ribosomal-DNA gene sequences were considered the best candidate to confirm the species of the larvae found. Our results showed that the homology compared with P. skrjabini was 99.5% in GenBank. Subsequently, we preliminarily identified two species of horn flies through morphological observation and then sequenced the mitochondrial-DNA-gene cytochrome oxidase subunit I obtained from two species of horn flies, with 100 and 99.2% similarity to sequences deposited in GenBank, respectively. Thus, we identified Haematobia titillans and Haematobia irritans and provided evidence for their potential role as vectors of parabronemosis. Our study provides reference for future research on the life history of the nematode and the vectors of parabronemosis.
In this work, we are concerned with a time-splitting Fourier pseudospectral (TSFP) discretization for the Klein-Gordon (KG) equation, involving a dimensionless parameter ɛ ∊ (0,1]. In the nonrelativistic limit regime, the small ɛ produces high oscillations in exact solutions with wavelength of (ɛ2) in time. The key idea behind the TSFP is to apply a time-splitting integrator to an equivalent first-order system in time, with both the nonlinear and linear subproblems exactly integrable in time and, respectively, Fourier frequency spaces. The method is fully explicit and time reversible. Moreover, we establish rigorously the optimal error bounds of a second-order TSFP for fixed ɛ = (1), thanks to an observation that the scheme coincides with a type of trigonometric integrator. As the second task, numerical studies are carried out, with special efforts made to applying the TSFP in the nonrelativistic limit regime, which are geared towards understanding its temporal resolution capacity and meshing strategy for (ɛ2)-oscillatory solutions when 0 < ɛ « 1. It suggests that the method has uniform spectral accuracy in space, and an asymptotic (ɛ−2Δt2) temporal discretization error bound (Δt refers to time step). On the other hand, the temporal error bounds for most trigonometric integrators, such as the well-established Gautschi-type integrator in, are (ɛ−4Δt2). Thus, our method offers much better approximations than the Gautschi-type integrator in the highly oscillatory regime. These results, either rigorous or numerical, are valid for a splitting scheme applied to the classical relativistic NLS reformulation as well.
Experimental studies have suggested that tea consumption could lower the risk of dyslipidaemia. However, epidemiological evidence is limited, especially in southern China, where oolong tea is the most widely consumed beverage. We conducted a population-based case–control study to evaluate the association between consumption of tea, especially oolong tea, and risk of dyslipidaemia in Shantou, southern China, from 2010 to 2011. Information on tea consumption, lifestyle characteristics and food consumption frequency of 1651 patients with newly diagnosed dyslipidaemia and 1390 controls was obtained using a semi-quantitative questionnaire. Anthropometric variables and serum biochemical indices were determined. Drinking more than 600 ml (2 paos) of green, oolong or black tea daily was found to be associated with the lowest odds of dyslipidaemia risk (P< 0·001) when compared with non-consumption, but only oolong tea consumption was found to be associated with low HDL-cholesterol levels. A dose–response relationship between duration of tea consumption and risk of dyslipidaemia (OR 0·10, 95 % CI 0·06, 0·16), as well as that between amount of dried tea leaves brewed and risk of dyslipidaemia (OR 0·34, 95 % CI 0·24, 0·48), was found. Moreover, consumption of oolong tea for the longest duration was found to be associated with 3·22, 11·99 and 6·69 % lower blood total cholesterol, TAG and LDL-cholesterol levels, respectively. In conclusion, the present study indicates that long-term oolong tea consumption may be associated with a lower risk of dyslipidaemia in the population of Shantou in southern China.
It is important to know the detailed DNA structure on carbonaceous surfaces for further application of DNA-functionalized carbonaceous materials in diverse research areas. In this study, the topographic and structural characteristics of the separated single DNA molecules and their assembly on highly oriented pyrolytic graphite (HOPG) surfaces have been investigated by atomic force microscopy (AFM). AFM results indicate that both circular and linear DNA molecules tend to form hexagonal patterns along with some unusual structures that include node, protrusion, cruciform, parallel single-stranded DNA (ssDNA), and compact zigzag. Furthermore, parallel ssDNA patterns and their crossed structures have been obtained under high-temperature conditions. Our AFM results reveal that a bare HOPG surface can induce DNA molecules to form various unusual structures. This finding is helpful for understanding the adsorption behavior of DNA on other carbonaceous surfaces such as carbon nanotubes and graphene. In addition, the hexagonal DNA patterns in this study are similar to those formed on the alkylamine-modified HOPG surface, which implies that a bare HOPG, without any chemical modification, has a strong ability to align biomolecules. This study could expand our knowledge of the diversities of DNA structures and the aligning ability of carbonaceous surfaces.
The adsorption of humic acid (HA) onto highly ordered pyrolytic graphite (HOPG) surfaces at different concentrations has been studied by atomic force microscopy. When HA concentration was increased from 10 to 1,000 mg/L, HA can sequentially form spherical particles, layered structures, and connected blocks on HOPG surfaces. The findings of the layer structures and small amount of fine chains have been verified and discussed. When HA was acidified by addition of acetic acid, it changed into small rigid particles. These results indicated that HA can be considered as supramolecular associations of self-assembling heterogeneous and relatively small molecules, and a small amount of polymers. The present results are important for understanding HA molecular structures and their adsorption characteristic on carbonaceous surfaces.
The influence of the density of gap states and the band gap width of the intrinsic a-Si:H active layer on the characteristics of a-Si PIN/OLED coupling pair was analyzed by a-Si:H PIN/OLED CAD simulation model. The CAD simulation model was carried out based on a-Si PIN Hack & Shur model and OLED TCL transport model. At the same band gap width, for the intrinsic a-Si:H active layer with the higher density of gap states, the reverse current of a-Si PIN trended to be saturated at the higher reverse bias voltage. As a result, I-V curve of a-Si PIN/OLED around the turn point Vt became smoother with the increase of the density of gap states. At the same state density, the light induced current of a-Si PIN increased against the band gap width, assuming the input light had the same spectrum as AM1.5 solar light. Thus the luminance emitted from OLED increased with the decrease of the band gap width because OLED belongs to the light-emitting device controlled by current. The simulation results also showed that the influence of the state density intensified with the increase of the band gap of a-Si:H.
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