Multiphase hemodynamic simulation of pulsatile flow in a coronary artery

A multiphase transient non-Newtonian three-dimensional (3-D) computational fluid dynamics (CFD) simulation has been performed for pulsatile hemodynamics in an idealized curved section of a human coronary artery. We present the first prediction, to the authors' knowledge, of particulate buildup on the inside curvature using the multiphase theory of dense suspension hemodynamics. In this study, the particulates are red blood cells (RBCs). The location of RBC buildup on the inside curvature correlates with lower wall shear stress (WSS) relative to the outside curvature. These predictions provide insight into how blood-borne particulates interact with artery walls and hence, have relevance for understanding atherogenesis since clinical observations show that atherosclerotic plaques generally form on the inside curvatures of arteries. The buildup of RBCs on the inside curvature is driven by the secondary flow and higher residence times. The higher viscosity in the central portion of the curved vessel tends to block their flow, causing them to migrate preferentially through the boundary layer. The reason for this is the nearly neutrally buoyant nature of the dense two-phase hemodynamic flow. The two-phase non-Newtonian viscosity model predicts greater shear thinning than the single-phase non-Newtonian model. Consequently, the secondary flow induced in the curvature is weaker. The waveforms for computed hemodynamic parameters, such as hematocrit, WSS, and viscosity, follow the prescribed inlet velocity waveforms. The lower oscillatory WSS produced on the inside curvature has implications for understanding thickening of the intimal layer.     

川崎病及川崎病冠状动脉病变患儿肠道菌群变化

研究川崎病及川崎病冠状动脉病变患儿肠道菌群变化情况, 为调节其肠道菌群提供参考。

选择我院2018年7月至2020年5月纳入的97例川崎病患儿作为观察对象, 依据超声心动图检查将其中出现冠状动脉病变的45例患儿作为研究组, 另外52例单纯川崎病患儿作为对照组, 检测两组患儿肠道菌群情况。

两组患儿肠道菌群多样性相比差异无统计学意义(P > 0.05), 但研究组患儿肠道菌群丰度高于对照组(P < 0.05)。研究组患儿肠道厚壁菌门占35.85%, 低于对照组的54.06%(P < 0.05)。研究组患儿肠道拟杆菌门占33.57%, 高于对照组的21.30%(P < 0.05)。研究组患儿肠道变形菌门占24.39%, 与对照组的25.21%相比差异无统计学意义(P > 0.05)。研究组患儿肠道乳杆菌属、拟杆菌属、韦荣球菌属分别占3.87%、25.03%、2.75%, 与对照组的21.23%、16.23%、17.95%相比差异均有统计学意义(均P < 0.05)。

川崎病冠状动脉病变患儿肠道菌群状况与单纯川崎病患儿存在显著差异, 合并冠状动脉病变的患儿肠道菌群紊乱更为显著, 应受到临床重视。

     

Photoacoustic assessment of hemodynamic changes in foot vessels

Monitoring the blood supply in the lower extremities is critical for individuals who are vulnerable to vascular dysfunction. Current clinical approaches are ineffective in observing hemodynamic changes in peripheral vessels. In this paper, we investigate the potential of photoacoustic tomography (PAT) as an alternative way to in vivo monitor hemodynamic changes in foot vessels. High spatial and temporal resolution maps of hemoglobin in major arteries and veins are shown. Results from twelve human subjects are presented here to visualize vascular perfusion of healthy volunteers in two age groups (young vs aged). Significant differences between the two groups are observed and verify the declining in vascular function with aging, highlighting the potential of PAT as a new tool to evaluate vascular function in the lower extremities.      

ReCiPe2016: a harmonised life cycle impact assessment method at midpoint and endpoint level

Purpose

Life cycle impact assessment (LCIA) translates emissions and resource extractions into a limited number of environmental impact scores by means of so-called characterisation factors. There are two mainstream ways to derive characterisation factors, i.e. at midpoint level and at endpoint level. To further progress LCIA method development, we updated the ReCiPe2008 method to its version of 2016. This paper provides an overview of the key elements of the ReCiPe2016 method.

Methods

We implemented human health, ecosystem quality and resource scarcity as three areas of protection. Endpoint characterisation factors, directly related to the areas of protection, were derived from midpoint characterisation factors with a constant mid-to-endpoint factor per impact category. We included 17 midpoint impact categories.

Results and discussion

The update of ReCiPe provides characterisation factors that are representative for the global scale instead of the European scale, while maintaining the possibility for a number of impact categories to implement characterisation factors at a country and continental scale. We also expanded the number of environmental interventions and added impacts of water use on human health, impacts of water use and climate change on freshwater ecosystems and impacts of water use and tropospheric ozone formation on terrestrial ecosystems as novel damage pathways. Although significant effort has been put into the update of ReCiPe, there is still major improvement potential in the way impact pathways are modelled. Further improvements relate to a regionalisation of more impact categories, moving from local to global species extinction and adding more impact pathways.

Conclusions

Life cycle impact assessment is a fast evolving field of research. ReCiPe2016 provides a state-of-the-art method to convert life cycle inventories to a limited number of life cycle impact scores on midpoint and endpoint level.

     

Basic quantitative risk assessment of light sources: Comparison of light exposure assessment and endpoint life cycle impact assessment

Human Health Area of Protection (HHAoP) has been receiving greater emphasis in recent years in the scope of Environmental Impact Assessment (EIA) of products or services with more impact categories specifically dedicated to include different dimensions of HHAoP. Human health impacts of light sources, however, have received less attention despite their prevalent use for backlighting, general lighting and architectural purposes. Currently, Environmental Product Declarations (EPDs) of lighting devices and electronic devices with backlit screens do not address endpoint impacts nor do they specify technical properties of the light that can enable such an assessment. This study investigates endpoint impacts of eleven lighting devices (1) due to light exposure during the use phase and (2) due to emissions throughout their life cycle. Impacts are quantified as disease burden in terms of disability adjusted life years (DALY). The burden of exposure was calculated using attributable fraction (AF) method. The burden due to life cycle emissions was quantified using GaBi software and built-in life cycle impact assessment (LCIA) method ReCiPe. Endpoint impact categories included were climate change human health, human toxicity, ionizing radiation, ozone depletion, particulate matter formation, and photochemical oxidant formation. The disease burden due to light exposure of all light sources is of two orders of magnitude greater than the disease burden due to life cycle emissions pointing to the need for its treatment.     

The momentum of a population whose birth rates gradually change to replacement levels

A formula is given for computing the ultimate size of a population whose birth rates change over a finite time to replacement levels. This formula is derived in the context of the usual discrete-time version of the one-sex model of population growth and represents an extension of work by Keyfitz and others. When birth and death rates tend over an infinite time to replacement levels, necessary and sufficient conditions are investigated for the ultimate population size to be finite and nonzero.     

Intracardiac echocardiographic guidance for hemodynamic assessment in a patient with congenital abnormalities and a prosthetic aortic valve

In this case report, we present the use of intracardiac echocardiography (ICE) for guiding the cardiac catheterization and subsequent hemodynamic investigation in an unusual patient case with multiple congenital abnormalities (bicuspid aortic valve, left cervical aortic arch, two aortic coarctations) and two aortic valve replacement operations in the past. The ICE catheter (AcuNav) permitted us to accurately and safely puncture the interatrial septum and place the Swan-Ganz catheter in the left ventricle; additionally, visualization of the aortic coarctation in the ascending aorta was also achieved.     

MCP-1和VEGF与冠心病患者冠脉病变程度的关系及介入前后的变化和意义

目的:探讨单核细胞趋化蛋白1(MCP-1)和血管内皮生长因子VEGF与冠心痛患者冠脉病变程度的关系及介入前后的变化和意义.方法:选择经冠状动脉造影确诊的冠心痛患者105例,根据病变程度分为单支病变组(A组)、双支病变组(B组)和多支病变组(C组),同时选择经冠状动脉造影确诊的正常时照组35例(D组),采用双抗体夹心ELISA法洲定术前术后血清MCP-1和VEGF水平.结果:1.血清MCP-1水平测定结果冠心病组明显高于正常对照组,三支病变组高于双支病变组,双支病变组高于单支病变组,支架置入术后显著高于术前,差异均有统计学意义(P<0.01),对照组术前术后相比差异无统计学意义(P>0.05).2血清VEGF水平测定结果显示:冠心病组明显高于正常对照组,三支病变组高于双支病变组和单支病变组,差异均有统计学意义(P<0.01),双支病变组与单支病变组间差异无统计学意义(P>0.05),支架置入术后较术前显著降低(P<0.01),术后冠心病组与对照组相比差异无统计学意义(P>0.05),对照组术前术后差异无统计学意义(P>0.05).结论:冠心病患者血清MCP-1、VEGF水平与冠脉病变程度密切相关,介入治疗可影响冠心病患者血清MCP-1水平的升高和VEGF水平降低,监测血清中MCP-1和VEGF水平变化可了解治疗效果和炎症程度.     

Circadian change of heat loss in response to change in core temperature in rats

1. 1.|Circadian changes in heat production (M), heat loss (H), core temperature (T_c) and feeding activity (FA) of ad-lib fed rats were observed by direct and indirect calorimetry.

2. 2.|M, H and T_c showed a clear nocturnal increase associated with several discrete increases.

3. 3.|Whereas the slope of M vs T_c relation did not change appreciably within a day, the slope of H vs T_c or thermal conductance vs T_c relation tended to decrease at night, implying that the correlation between heat loss and body temperature is also a function of time of day in rats.

Marfan syndrome with coronary artery lesions in a North American Indian.

Marfan syndrome has not been well documented in North American Indians. A 19-year old Ojibwa man had evidence of this syndrome -- specifically, tall stature, long, thin extremities (particularly, fingers and toes), increased urinary excretion of hydroxyproline, aortic aneurysm, aortic regurgitation and pathologic evidence of aortic rupture and alastic tissue fragmentation. Intimal hyperplasia was present in the extramural coronary arteries, while the intramural arteries, usually thought to be involved, were normal.     

Macroproteinemia and the prognostic assessment of blood loss

The dependence of blood loss quantitative indices (duration, number and volume of exfusions) on the initial state of the blood protein system was studied in experiments with dogs. The true correlation was found between the macroprotein contents in plasma and the duration of the arterial pressure compensation phase at the level of 5.3 kPa (40 mm Hg). Hypermacroproteinemia is evident of low organism stability (resistance) and is an unfavourable prognostic characteristic in experimental blood loss.     

Real-time optical analysis of a colorimetric LAMP assay for SARS-CoV-2 in saliva with a handheld instrument improves accuracy compared with endpoint assessment

Controlling the course of the Coronavirus Disease 2019 (COVID-19) pandemic will require widespread deployment of consistent and accurate diagnostic testing of the novel Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Ideally, tests should detect a minimum viral load, be minimally invasive, and provide a rapid and simple readout. Current Food and Drug Administration (FDA)-approved RT-qPCR–based standard diagnostic approaches require invasive nasopharyngeal swabs and involve laboratory-based analyses that can delay results. Recently, a loop-mediated isothermal nucleic acid amplification (LAMP) test that utilizes colorimetric readout received FDA approval. This approach utilizes a pH indicator dye to detect drop in pH from nucleotide hydrolysis during nucleic acid amplification. This method has only been approved for use with RNA extracted from clinical specimens collected via nasopharyngeal swabs. In this study, we developed a quantitative LAMP-based strategy to detect SARS-CoV-2 RNA in saliva. Our detection system distinguished positive from negative sample types using a handheld instrument that monitors optical changes throughout the LAMP reaction. We used this system in a streamlined LAMP testing protocol that could be completed in less than 2 h to directly detect inactivated SARS-CoV-2 in minimally processed saliva that bypassed RNA extraction, with a limit of detection (LOD) of 50 genomes/reaction. The quantitative method correctly detected virus in 100% of contrived clinical samples spiked with inactivated SARS-CoV-2 at either 1× (50 genomes/reaction) or 2× (100 genomes/reaction) of the LOD. Importantly, the quantitative method was based on dynamic optical changes during the reaction and was able to correctly classify samples that were misclassified by endpoint observation of color.