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101.
Aves are represented by abundant fossil remains in Quaternary sites. Birds are well adapted to the environment they inhabit, so they make very good paleoenvironmental indicators for Quaternary sites. Here we analyse the avian remains from the Late Pleistocene (probably MIS3) site of Aguilón P-7 (AGP-7). The Pleistocene sediments fill up a shallow cave, which is located in the Zaragozan part of the Iberian Range, 55 km south of the city of Zaragoza. We have for the first time provided a taxonomic and taphonomic study of the avian assemblage of AGP-7, as well as a preliminary paleoenvironmental analysis based on these data. Nine avian taxa have been identified: Galliformes indet., Lagopus sp., Aquila chrysaetos, Gyps fulvus, Passeridae indet., Anthus sp., Prunella modularis,Sturnus cf. unicolor and Corvus monedula. The taphonomic analysis did not provide conclusive information. However, it suggests an accumulation of uneaten food remains by diurnal birds of prey. The identified taxa currently inhabit the Iberian Peninsula, populating woodland environments with rocky areas. They are found in areas with an oceanic climate, in contrast to the Mediterranean climate that now prevails in Aguilón.  相似文献   
102.
A proper analysis of blood flow is contingent upon accurate modelling of the branching pattern and vascular geometry of the network of interest. It is challenging to reconstruct the entire vascular network of any organ experimentally, in particular the pulmonary vasculature, because of its very high number of vessels, complexity of the branching pattern and poor accessibility in vivo. The objective of our research is to develop an innovative approach for the reconstruction of the full pulmonary vascular tree from available morphometric data. Our method consists of the use of morphometric data on those parts of the pulmonary vascular tree that are too small to reconstruct by medical imaging methods. This method is a three-step technique that reconstructs the entire pulmonary arterial tree down to the capillary bed. Vessels greater than 2 mm are reconstructed from direct volume and surface analysis using contrast-enhanced computed tomography. Vessels smaller than 2 mm are reconstructed from available morphometric and distensibility data and rearranged by applying Murray's laws. Implementation of morphometric data to reconstruct the branching pattern and applying Murray's laws to every vessel bifurcation simultaneously leads to an accurate vascular tree reconstruction. The reconstruction algorithm generates full arterial tree topography down to the ?rst capillary bifurcation. Geometry of each order of the vascular tree is generated separately to minimize the construction and simulation time. The node-to-node connectivity along with the diameter and length of every vessel segment is established and order numbers, according to the diameter-de?ned Strahler system, are assigned. In conclusion, the present model provides a morphological foundation for future analysis of blood flow in the pulmonary circulation  相似文献   
103.
目的:研究16层螺旋电子计算机断层扫描(CT)三维重建与数字化摄影(DR)平片检查对外伤性肋骨骨折的诊断价值,为临床诊治提供参考。方法:将2017年6月至2018年6月期间于本院接受诊治的82例外伤性肋骨骨折患者作为研究对象,所有患者均接受16层螺旋CT三维重建与DR平片检查,观察并记录患者的骨折发生部位,并比较两种诊断方法对外伤性肋骨骨折诊断的准确率、灵敏度、特异性、阳性预测值、阴性预测值以及漏诊情况。结果:82例外伤性肋骨骨折患者经影像学与临床诊断明确发生骨折179处,多发性骨折发生率为62.20%,单发性骨折发生率为37.80%,骨折肋骨段位中4-10段骨折发生率最高为69.83%,骨折肋骨水平阶段中腋肋骨折发生率最高为59.78%。相较于DR平片,16层螺旋CT三维重建诊断外伤性肋骨骨折的准确率、灵敏度、特异性、阳性预测值、阴性预测值更高,漏诊率更低,差异有统计学意义(P0.05)。结论:相较于DR平片检查,应用16层螺旋CT三维重建检查外伤性肋骨骨折能明显提高临床诊断的准确率、灵敏度和特异性,减少漏诊,可为临床诊治提供更可靠的信息,值得临床推广。  相似文献   
104.
目的:探讨64排螺旋CT对粗隆间骨折Evans分型的影响,为临床使用提供参考依据。方法:2015年3月至2017年3月,三甲医院高年资创伤骨科主任医师2名,医师1、医师2分别按照术前X线、术前64排螺旋CT平扫和三位重建结果对128例新鲜闭合单侧粗隆间骨折患者进行Evans分型,分别记为X线分型、CT分型。本院术者依据围术期X线、CT及术中所见骨折情况进行Evans分型(逆粗隆间骨折定义为Ⅴ型)作为最终分型。记录分型结果,计算并对比准确率、误诊率。结果:(1)剔除5例,90.09%(123/128)的患者完成研究。(2)分型结果:X线分型中,3例(最终分型Ⅲ型2例,Ⅳ型1例)无法定型;Ⅰ型正确1例,改为Ⅱ型1例;Ⅱ型正确18例,改为Ⅰ型2例,改为Ⅲ型3例,Ⅳ型2例;Ⅲ型正确45例,改为Ⅱ型7例,改为Ⅳ型1例;Ⅳ型正确19例,改为Ⅱ型3例,改为Ⅲ型15例。CT分型中,Ⅰ型正确3例,Ⅱ型正确29例,Ⅲ型正确64例,改为Ⅳ型1例,Ⅳ型正确22例,Ⅴ型正确3例。(3)CT分型的总准确率、总误诊率优于X线分型(99.19%vs67.48%、0.81%vs30.08%,P0.05)。(4)Ⅰ型、Ⅱ型、Ⅲ型、Ⅳ型骨折进行CT分型,准确率高于X线分型(P0.05),误诊率低于X线分型(P0.05);Ⅴ型骨折,两种分型准确率、误诊率相等。结论:64排螺旋CT平扫及三维重建是粗隆间骨折Evans分型较为可靠的辅助检查,可考虑推广运用。  相似文献   
105.
Transition metal layered oxides have been the dominant cathodes in lithium‐ion batteries, and among them, high‐Ni ones (LiNixMnyCozO2; x ≥ 0.7) with greatly boosted capacity and reduced cost are of particular interest for large‐scale applications. The high Ni loading, on the other hand, raises the critical issues of surface instability and poor rate performance. The rational design of synthesis leading to layered LiNi0.7Mn0.15Co0.15O2 with greatly enhanced rate capability is demonstrated, by implementing a quenching process alternative to the general slow cooling. In situ synchrotron X‐ray diffraction, coupled with surface analysis, is applied to studies of the synthesis process, revealing cooling‐induced surface reconstruction involving Li2CO3 accumulation, formation of a Li‐deficient layer and Ni reduction at the particle surface. The reconstruction process occurs predominantly at high temperatures (above 350 °C) and is highly cooling‐rate dependent, implying that surface reconstruction can be suppressed through synthetic control, i.e., quenching to improve the surface stability and rate performance of the synthesized materials. These findings may provide guidance to rational synthesis of high‐Ni cathode materials.  相似文献   
106.
Aims Studies of the climatic responses of plant assemblages via vegetation-based environmental reconstructions by weighted averaging (WA) regression and calibration are a recent development in modern vegetation ecology. However, the performance of this technique for plot-based vegetation datasets has not been rigorously tested. We assess the estimation accuracy of the WA approach by comparing results, mainly the root mean square error of prediction (RMSEP) of WA regressions for six different vegetation datasets (total species, high-frequency species and low-frequency species as both abundance and incidence) each from two sites.  相似文献   
107.
108.
Understanding the dynamics of foot‐and‐mouth disease virus (FMDV), an endemic and economically constraining disease, is critical in designing control programmes in Africa. This study investigates the evolutionary epidemiology of SAT1 and SAT2 FMDV in Eastern Africa, as well as between cattle and wild African buffalo. Bayesian phylodynamic models were used to analyse SAT1 and SAT2 VP1 gene segments collected between 1975 and 2016, focusing on the SAT1 and SAT2 viruses currently circulating in Eastern Africa. The root state posterior probabilities inferred from our analyses suggest Zimbabwe as the ancestral location for SAT1 currently circulating in Eastern Africa (p = 0.67). For the SAT2 clade, Kenya is inferred to be the ancestral location for introduction of the virus into other countries in Eastern Africa (p = 0.72). Salient (Bayes factor >10) viral dispersal routes were inferred from Tanzania to Kenya, and from Kenya to Uganda for SAT1 and SAT2, respectively. Results suggest that cattle are the source of the SAT1 and SAT2 clades currently circulating in Eastern Africa. In addition, our results suggest that the majority of SAT1 and SAT2 in livestock come from other livestock rather than wildlife, with limited evidence that buffalo serve as reservoirs for cattle. Insights from the present study highlight the role of cattle movements and anthropogenic activities in shaping the evolutionary history of SAT1 and SAT2 in Eastern Africa. While the results may be affected by inherent limitations of imperfect surveillance, our analysis elucidates the dynamics between host species in this region, which is key to guiding disease intervention activities.  相似文献   
109.
近年来,分子标记和显微光学成像技术的系列突破,使得单细胞分辨的全脑尺度神经群落成像成为现实.然而,现有神经元形态重建工具的发展速度远远滞后于海量数据的产生速度,难以满足现阶段成像数据的分析需求.在此背景下,我们首先分析了神经元形态重建工具发展滞后的原因,简述现有半自动和全自动神经元形态重建工具的特点和最新发展,并结合现有工具的特点分析其向高通量、高准确度重建工具发展时面临的挑战.最后,我们对未来形态重建工具的发展趋势及应用前景做出展望.  相似文献   
110.

Background

The anterior cruciate ligament rupture is a common injury which mainly affects young and active population. Faced to this problem, the development of synthetic structures for ligament reconstruction is increasing. The most recent researches focused on the development of biodegradable structures that could be functionalized to enhance host integration. This work describes the elaboration of different poly(ε-caprolactone) prototypes for the rat anterior cruciate ligament replacement in order to found the best design for further in vivo assays.

Methods

According to the literature, it was decided to elaborate two different poly(ε-caprolactone) prototypes: a braided one and a free-fibers one. A chemical grafting of a bioactive polymer–poly(sodium styrene sulfonate) – was performed on both prototypes and mechanical and biological testing were assessed. Based on these results, one rat was implanted with the best prototype.

Results

The mechanical and biological results demonstrated that the best prototype to implant was the poly(sodium styrene sulfonate)-grafted braided prototype. After one-month implantation, no inflammation was observable around the scar. The rat demonstrated good flexion and extension of the lower limb without any anterior drawer. The prototype was highly anchored to the bone. ESEM images of the explanted prototype showed the presence of cells and tissue ingrowth along and around the fibers.

Conclusion

This work demonstrates the feasibility to implant a bioactive and biodegradable synthetic ligament in the rat model without any inflammation and with a good tissue anchoring at a short-term time. This will lead to an extensive in vivo assay.  相似文献   
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