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Calcification within breast cancer is a diagnostically significant radiological feature that generally consists of hydroxylapatite. Samples from 30 cases of breast carcinoma with calcification were investigated using optical microscopy, energy-dispersive X-ray analysis, transmission-electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, synchrotron radiation X-ray diffraction and X-ray fluorescence. Under optical microscopy, the calcifications were found to consist of either irregular aggregates with widths > 200 μm or spherical aggregates similar to psammoma bodies with an average diameter of 30 μm. Transmission-electron microscopy showed that short columnar or dumbbell-shaped crystals with widths of 10–15 nm and lengths of 20–50 nm were the most common morphology; spherical aggregates (~1 μm in diameter) with amorphous coatings of fibrous nanocrystals were also observed. Results indicated that hydroxylapatite was the dominant mineral phase in the calcifications, and both CO32– and cation substitutions (Na, Mg, Zn, Fe, Sr, Cu and Mn) were present in the hydroxylapatite structure. Fourier-transform infrared spectra show peaks at 872 and 880 cm–1 indicating that CO32– substituted both the OH– (A type) and PO43– (B type) sites of hydroxylapatite, making it an A and B mixed type. The ratio of B- to A-type substitution was estimated in the range of 1.1–18.7 from the ratio of peak intensities (I872/I880), accompanied with CO32– contents from 1.1% to 14.5%. Trace arsenic, detected in situ by synchrotron radiation X-ray fluorescence was found to be distributed uniformly in the calcifications in the form of AsO43– substituting for PO43–. It is therefore proposed that identifying these trace elements in breast cancer calcifications may be promising for future clinical diagnostics.
This paper presents a new approach to synthesize multi-loop mechanisms with three translational displacement parameters based on virtual-loop theory and Assur groups. The approach used kinematic links as a generalized link group added one-by-one to the output link, which further extends the unified link groups in the plane and space. Firstly, the concept of infinitesimal displacement parameters is introduced to describe the displacement parameters. The dependence on the change in the degree of freedom (DOF) and displacement parameters of the output link after adding a 0-DOF generalized link group is established. Then, the link groups with three displacement parameters are synthesized, and the intersection operation rules are given. The single-loop mechanism is synthesized under two circumstances. The 1-, 2-, and 3-DOF dual-loop mechanisms are obtained by adding corresponding generalized link groups. Finally, the multi-loop mechanisms are obtained by adding corresponding generalized link groups. Some novel mechanisms are synthesized to illustrate the effectiveness of the proposed approach.
The bark weevil, Pissodes yunnanensis Langor and Zhang, is an important pest of young Yunnan pine, Pinus yunnanensis Franchet (Pinaceae), in southwestern China. Populations of the host and weevil are disjunct, especially in the northwestern part of the range in Yunnan province. To estimate maternal gene flow and examine the genetic structure of Pissodes yunnanensis, we sequenced an 840-bp fragment of the mitochondrial cytochrome c oxidase I (COI) gene in 60 individuals from 7 populations in Yunnan and Guizhou provinces. Percent divergence among populations ranged from 0.001% to 2.1%. Nested clade analysis of 21 haplo types showed evidence of genetic structuring that is inferred to be primarily due to allopatric fragmentation and a low level of gene flow. Analysis of molecular variance also showed significant genetic structuring and restricted gene flow among weevil populations, especially between northwestern and eastern regions of the range. Such genetic structuring may be important for pest management programs. Phylogenetic analyses comparing the same 761-bp sequence among P. yunnanensis, Pissodes punctatus Langor and Zhang from southwestern China, and five Nearctic species of Pissodes showed that (i) the two Chinese species were most closely related to each other, (ii) the four species in the P. strobi (Peck) species group formed a distinct clade, and (iii) these two clades were more similar to each other than to the Nearctic species P. affinis Randall.
Pissodes yunnanensis Langor et Zhang, a pest of Yunnan pine, Pinus yunnanensis Franchet, in southwestern China, occurs at elevations of 2200–2800 m. These weevils infest Yunnan pine trees less than 20 years old but prefer trees 8–10 years old. Oviposition occurs mainly along the upper trunk on current-year and 1-year-old growth and occasionally on the upper lateral branches. Weevil feeding often kills the leader, which results in stem forking and crooking. At times, after 2–3 years of consecutive severe infestation, tree mortality occurs. In southwestern Yunnan Province, adults of this univoltine weevil emerge from infested stems from mid-April to mid-July. Eggs appear in late June, first-instar larvae in early July, and fourth-instar larvae in late March of the next year. First- and second-instar larvae feed in the phloem, and third-instar larvae move to the sapwood or pith, where they overwinter. In March, larvae resume feeding and development. Fourth-instar larvae excavate pupal chambers (chip cocoons) in the outer sapwood or pith, and pupation occurs from late March to late May. Optimal development of eggs and pupae occurs at 25 °C in the laboratory. Parasitism is the main cause of mortality in P. yunnanensis, accounting for 2%–25% of mortality among third- and fourth-instar larvae and 5%–10% among pupae.
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