基于蚁群行为及模糊聚类的乳腺钙化点边缘提取

针对乳腺X光图像中钙化点形态各异、周围背景复杂及其与背景对比度不同造成的钙化点识别难度大的问题,模仿蚁群行为对乳腺X光图像中各像素点按梯度值进行聚类,输出聚类中心;以这些聚类中心作为模糊C均值法(FCM)的初始聚类中心,经迭代得到新的聚类,再经过适当的类间合并,从而将钙化点边缘的像素提取出来.实验结果表明,通过选择适当的蚂蚁聚类及模糊C均值法参数,该方法可有效提取乳腺钙化点边缘.     

回转窑不同温度场钒渣物相演变规律探讨

通过对实验室模拟现场回转窑的6组不同温度点下焙烧渣样品进行钒尖晶石形貌变化、物相含量变化、钒元素的赋存规律及不同温度点下物相转变机理的研究。钒尖晶石形貌变化结果表明,整个焙烧过程中钒尖晶石形貌变化经历了致密光滑块状-氧化铁的镶边结构-钒尖晶石完全直接为隐晶质物质-小颗粒物质重新组合并且长大5个过程;矿物自动解理分析仪(MLA)物相含量分析数据显示焙烧过程中石灰石、铁橄榄石、钒尖晶石和白云石在逐渐减少,普通辉石相是逐渐增加,而氧化铁固溶体、部分氧化钒尖晶石、钒酸钙固溶体和铁板钛矿固溶体的变化趋势是先增加后减少;钒元素的赋存形式规律为绝大多数钒元素赋存于氧化物中,占到总量的85%左右,其次赋存于硅酸盐中,占到钒总含量的14%左右,还有极少部分分布于碳酸盐等矿物中;整个焙烧过程物相变化机理主要分为铁元素向外扩散-氧元素向内扩散-氧化物的化合过程-化合物雏形晶体的长大4个反应过程。     

Comparative ultrastructure and cytochemistry of the avian pineal organ

The breeding of birds is expected to solve problems of nourishment for the growing human population. The function of the pineal organ synchronizing sexual activity and environmental light periods is important for successful reproduction. Comparative morphology of the avian pineal completes data furnished by experiments on some frequently used laboratory animals about the functional organization of the organ. According to comparative histological data, the pineal of vertebrates is originally a double organ (the "third" and the "fourth eye"). One of them often lies extracranially, perceiving direct solar radiation, and the other, located intracranially, is supposed to measure diffuse brightness of the environment. Birds have only a single pineal, presumably originating from the intracranial pineal of lower vertebrates. Developing from the epithalamus, the avian pineal organ histologically seems not to be a simple gland ("pineal gland") but a complex part of the brain composed of various pinealocytes and neurons that are embedded in an ependymal/glial network. In contrast to organs of "directional view" that develop large photoreceptor outer segments (retina, parietal pineal eye of reptiles) in order to decode two-dimensional images of the environment, the "densitometer"-like pineal organ seems to increase their photoreceptor membrane content by multiplying the number of photoreceptor perikarya and developing follicle-like foldings of its wall during evolution ("folded retina"). Photoreceptor membranes of avian pinealocytes can be stained by antibodies against various photoreceptor-specific compounds, among others, opsins, including pineal opsins. Photoreceptors immunoreacting with antibodies to chicken pinopsin were also found in the reptilian pineal organ. Similar to cones and rods representing the first neurons of the retina in the lateral eye, pinealocytes of birds possess an axonal effector process which terminates on the vascular surface of the organ as a neurohormonal ending, or forms ribbon-containing synapses on pineal neurons. Serotonin is detectable immunocytochemically on the granular vesicles accumulated in neurohormonal terminals. Pinealocytic perikarya and axon terminals also bind immunocytochemically recognizable excitatory amino acids. Peripheral autonomic fibers entering the pineal organ through its meningeal cover terminate near blood vessels. Being vasomotor fibers, they presumably regulate the blood supply of the pineal tissue according to the different levels of light-dependent pineal cell activity.     

Biomaterials: Role of surface modifications

The fundamental concepts related to biomaterials and blood/tissue-material interactions at the interface have been reviewed. The relevance of surface modification to enhance blood and/or tissue compatibility of materials has been discussed and its role in selected prosthetic applications described.     

Effect of serum FGF‐23, MGP and fetuin‐A on calcium‐phosphate metabolism in maintenance hemodialysis patients

This study was aimed to explore the role of serum fibroblast growth factor (FGF)‐23, matrix Gla protein (MGP) and fetuin‐A in the calcium‐phosphate metabolism and their predicting value in coronary artery calcification in maintenance hemodialysis (MHD) patients. This study included 64 patients who receive hemodialysis in our hospital. The serum FGF‐23, MGP and fetuin‐A were analyzed by enzyme‐linked immunosorbent assay (ELlSA). Coronary artery calcification score (CACS) was evaluated by coronary artery computed tomography scan. The 64 patients (30 males, 34 females, 60.6 ± 11.3 years of age) received an average dialysis vintage of 6.88 ± 2.94 years. We divided the CACS into three levels, and 13 (20.31%), 16 (25%), and 35 (54.69%) exhibited a CACS of 0–100, 100–400, and >400, respectively. Dialysis vintage, serum FGF‐23, fetuin‐A, phosphorus and high‐density lipoprotein‐C levels were identified as independent variables of CACS by stepwise multiple regression analysis. The area under receiver operating characteristic curve indicated that serum FGF‐23 and fetuin‐A were useful for identifying CAC in MHD patients. The cut‐off value corresponding to the highest Youden's index was serum FGF‐23 ≥ 256 pg/mL and fetuin‐A ≤ 85 μg/mL, which was defined as the optimal predictors of CAC. Different combinations of serum FGF‐23 and fetuin‐A in parallel or in series effectively boosted the identification of CAC. The incidence of CAC is high in MHD patients. Serum FGF‐23 and fetuin‐A levels are closely correlated with CAC.     

Lanthionine,a Novel Uremic Toxin,in the Vascular Calcification of Chronic Kidney Disease: The Role of Proinflammatory Cytokines

Vascular calcification (VC) is a risk factor for cardiovascular events and mortality in chronic kidney disease (CKD). Several components influence the occurrence of VC, among which inflammation. A novel uremic toxin, lanthionine, was shown to increase intracellular calcium in endothelial cells and may have a role in VC. A group of CKD patients was selected and divided into patients with a glomerular filtration rate (GFR) of <45 mL/min/1.73 m² and ≥45 mL/min/1.73 m². Total Calcium Score (TCS), based on the Agatston score, was assessed as circulating lanthionine and a panel of different cytokines. A hemodialysis patient group was also considered. Lanthionine was elevated in CKD patients, and levels increased significantly in hemodialysis patients with respect to the two CKD groups; in addition, lanthionine increased along with the increase in TCS, starting from one up to three. Interleukin IL-6, IL-8, and Eotaxin were significantly increased in patients with GFR < 45 mL/min/1.73 m² with respect to those with GFR ≥ 45 mL/min/1.73 m². IL-1b, IL-7, IL-8, IL-12, Eotaxin, and VEGF increased in calcified patients with respect to the non-calcified. IL-8 and Eotaxin were elevated both in the low GFR group and in the calcified group. We propose that lanthionine, but also IL-8 and Eotaxin, in particular, are a key feature of VC of CKD, with possible marker significance.     

Vascular Calcification: Key Roles of Phosphate and Pyrophosphate

Cardiovascular complications due to accelerated arterial stiffening and atherosclerosis are the leading cause of morbimortality in Western society. Both pathologies are frequently associated with vascular calcification. Pathologic calcification of cardiovascular structures, or vascular calcification, is associated with several diseases (for example, genetic diseases, diabetes, and chronic kidney disease) and is a common consequence of aging. Calcium phosphate deposition, mainly in the form of hydroxyapatite, is the hallmark of vascular calcification and can occur in the medial layer of arteries (medial calcification), in the atheroma plaque (intimal calcification), and cardiac valves (heart valve calcification). Although various mechanisms have been proposed for the pathogenesis of vascular calcification, our understanding of the pathogenesis of calcification is far from complete. However, in recent years, some risk factors have been identified, including high serum phosphorus concentration (hyperphosphatemia) and defective synthesis of pyrophosphate (pyrophosphate deficiency). The balance between phosphate and pyrophosphate, strictly controlled by several genes, plays a key role in vascular calcification. This review summarizes the current knowledge concerning phosphate and pyrophosphate homeostasis, focusing on the role of extracellular pyrophosphate metabolism in aortic smooth muscle cells and macrophages.     

某生产性IC反应器内颗粒污泥钙化规律的追踪调研

为了解处理废纸造纸废水的颗粒污泥钙化规律,对陕西某废纸造纸废水处理厂IC反应器内颗粒污泥的钙化进行了1年的跟踪调研,考察了颗粒污泥钙化过程中的形态结构、无机物含量和类型及厌氧处理效果。结果表明,随着颗粒污泥钙化程度的加深,颗粒污泥对Ca~(2+)、COD的去除率下降,颗粒污泥中无机成分含量增加,干燥后的颗粒污泥颜色由深变浅;从颗粒污泥中的无机物类型来看,前期是以方解石形式存在的CaCO_3为主且掺杂少量SiO_2,后期是方解石和文石两种形式共存的CaCO_3,同时还伴随有FeCO_3、Fe_2O_3。从颗粒污泥的结构来看,颗粒污泥的孔隙和空穴在减少,被呈片状和粒状聚集体的沉积物所覆盖,杆状菌和球菌等减少。高通量测序对颗粒污泥中产甲烷菌的分类进行了分析,发现随着反应器运行时间的延长,乙酸型产甲烷菌的比例在逐渐增加,氢营养型产甲烷菌的比例在大幅度减少。最后综述了现有的钙化防治措施或办法,并从微生物角度提出了通过富集功能菌群来减缓钙化的新思路。     

Calcium-activated geopolymer ceramics: Study of powder calcination and amorphous gel phases

Burnt coal cinder (BCC), the main solid waste in coal and electric power industries was used to prepare the geopolymer ceramics (GC) in this study. The optimum preparation technology of BCC-based GC and the effects of calcination and calcification on the compressive strength of BCC-based GC were studied. Through the calcification of BCC with CaO, NaAlO₂ and sodium silicate solution (SS) were separately used as the co-activator and silica additive to prepare BCC-based GC. The optimal single-factor conditions determined by the experiment were BCC:CaO:NaAlO₂:SS = 18:3:2:4 (g:g:g:mL) and the liquid–solid ratio was 0.46. The compressive strength of BCC-based GC was 32.78 MPa (28 days). It was obtained that the calcination of calcified BCC below the temperature of 1000°C can effectively remove the fixed carbon in BCC but will destroy amorphous active aluminosilicate. The microstructure study showed that BCC reacted in the ternary system of Ca–Al–Si to form a variety of amorphous products (C–(A)–S–H and (N, C) –A–S–H). Along with the three-dimensional amorphous gel structure as the dominant phase, the coexistence and interlacing of various amorphous gels made the microstructure more compact and increased the compressive strength of the BCC-based GC. GCs with various amorphous phases have been successfully prepared at low temperature, and it also provided a new idea for the utilization of low-activity silicate solid wastes.     

Precise Starving Therapy via Physiologically Dependent Photothermal Conversion Promoted Mitochondrial Calcification Based on Multi-Functional Gold Nanoparticles for Effective Tumor Treatment

Starving therapy based on tumor calcification has been considered as a promising strategy with high biosafety for tumor treatment. However, the limited calcium (Ca²⁺) concentration in/around tumor tissue as well as the slow and uncontrollable process of the physiological calcification are all challenges for its application. Herein, a sialic acid (SA, Ca²⁺ chelator), folic acid (FA, tumor targeting agent) and triphenylphosphine (TPP, mitochondrial targeting agent) co-modified gold nanoparticles (SFT-Au) are fabricated to take advantage of the abundant Ca²⁺ in mitochondria as well as the Ca²⁺ collection and Ca²⁺ dependent photothermal property of SFT-Au to achieve a precise and promoted calcification of tumor mitochondria for effective starving therapy. During therapy, the SFT-Au will first accumulate in tumor mitochondria through stepwise targeting processes medicated by FA and TPP. After that, the SA further binds with the over-expressed Ca²⁺ in tumor mitochondria to induce the aggregation of SFT-Au, which not only gathers Ca²⁺ to initiate the calcification of mitochondria, but in situ generates photothermal agent to perform photothermal conversion under 808 nm irradiation to promote the calcification, resulting in effective prohibition of the energy metabolism in tumor cells for starving therapy and continuously photothermal damage of tumor cells to enhance the therapeutic efficiency.