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61.
基于生态网络分析的南京主城区重要生态斑块识别 总被引:5,自引:0,他引:5
在城市化程度较高,用地极为紧张的大都市,识别重要的生态斑块对其进行保留和修复不仅对控制大城市的城市过度扩张、提升城市品质、优化人居环境具有重要意义,也具有较强可操作性。以南京市主城区为例,在GIS技术的支撑下,(1)将景观阻力分析和网络分析相结合,定量表征研究区的潜在生态廊道,构建生态网络,寻找生态节点;(2)对城市中生态斑块的特殊服务功能进行分析,筛选出具备河流生态防护、隔离工业污染和居民休闲功能的生态斑块;(3)对生态斑块的规模进行分析,提取面积较大的斑块。综合分析后识别出7个重要的节点斑块,建议对其进行立法保护和修复,划定为永久绿地或永久生态空间,并对其建设方向提出意见。 相似文献
62.
63.
Summary Affinity of lymphoid cells for the microenvironment of germinal centers (GC), as detectable in transfer experiments by rapid homing in spleen GC from the blood, is a capacity expressed by only a subset of lymphoid cells, in particular by those constituting a GC. However, when introduced into the blood stream, these cells do not home into GC of lymph nodes and gut-associated lymphoid tissues. To investigate further this homing inability for high endothelial venule (HEV)-containing lymphoid tissues, GC cells isolated from donor rabbit appendix were labeled in vitro with 3H-leucine and injected into an afferent lymph vessel of recipient popliteal lymph nodes. Draining lymph nodes were removed 15 min to 24 h after cell administration and prepared for radioautography. For reference, the migration of cells isolated from Peyer's patches and thoracic duct lymph was also studied. By use of appendix GC cells, large numbers of labeled cells were found to migrate into GCs of the outer cortex centripetally, i.e., from the subcapsular sinus through the lymphocyte corona into the GC proper. The same was observed for cells from Peyer's patches, although in smaller numbers. Thoracic duct lymphocytes were only localized in the lymphocyte corona and the deep cortex. Thus, appendix GC cells and a subpopulation of cells from Peyer's patches can reach lymph node GC, but only when administered intralymphatically. We conclude that cells expressing affinity for the GC microenvironment do so for both spleen and lymph node GC, but do not have the capacity to interact with the wall of HEV; its implication for the understanding of the dynamics of a GC reaction is discussed.Abbreviations
GC
germinal center
- GCC
germinal-center cells
-
AGCC
appendix germinal-center cells
-
GCPC
germinal-center precursor cells
-
GCSC
germinal-center seeking cells
-
HEV
high endothelial venules
-
SRBC
sheep red blood cells
-
PP
Peyer's patch
-
TDL
thoracic duct lymphocytes
-
NCS
newborn calf serum
-
PBS
phosphate-buffered saline
-
PNA
peanut agglutinin
-
LN
lymph node
-
LC
lymphocyte corona
-
DC
deep cortex unit 相似文献
64.
Terminal galactosyl residues of cell-surface glycoconjugates exposed on both human and murine immature T- and B-cells 总被引:1,自引:0,他引:1
Dr. Andreas Raedler Elisabeth Raedler Rüdiger Arndt Heinz-Günter Thiele 《Cell and tissue research》1981,218(1):219-226
Summary Exposure of terminal galactosyl residues on cell-surface molecules as detected by their ability to bind peanut lectin (PNL) is found to be characteristic for immature cortical human and murine thymic lymphocytes. While in prenatal mice PNL staining is found to be uniformly distributed among all thymic lymphocytes, in adult thymi a cortico-medullary gradient is detectable concerning the PNL-binding capacity of thymic cortical lymphocytes, a phenomenon that appears to be correlated to their maturational degree.In secondary lymphatic tissue, i.e. lymph nodes and spleen of man, mouse and rat, strongly labeled cells are found exclusively in germinal centers. Ultrastructurally, these cells could be identified as centrocytes and centroblasts. These observations suggest that exposed galactosyl moieties of cell-surface glycoconjugates are expressed by undifferentiated lymphocytes of both T-and B-cell lineage.Furthermore, it could be shown that PNL-binding properties of immature cells are not restricted to lymphatic tissue but can also be demonstrated on various embryonic cells of non-lymphatic origin in distinct developmental stages. Thus, they might have a fundamental significance in the course of maturation processes.Supported by the Deutsche Forschungsgemeinschaft 相似文献
65.
Multiple buds have been induced from cotyledonary nodes of cashew, Anacardium occidentale L. Maximum number of buds were initiated on Murashige & Skoog's (MS) medium supplemented with 117 mM sucrose, 14.6 mM maltose and 22.2 M BA. The buds were harvested at each subculture after elongation on MS medium supplemented with 100 ml l-1 coconut water, 14.6 mM maltose, increased sucrose (146 mM) and decreased BA (4.4 M). Excised microshoots were rooted in vitro on MS medium in the presence of 117 mM sucrose, 2.9 M IAA and 4.9 M IBA. Plantlets have been successfully transferred to soil and have been established in the field. 相似文献
66.
CD4+ T cell proliferation depends on the balance between NO and extra-cellular superoxide (O2-). By reducing NO bio-availability, O2- promotes splenic T cell proliferation and immune response intensity. Here, we show that spleen cells from na?ve mice produced neither NO nor O2- during T cell activation, but Gr-1+ splenocytes from primed mice regulated Ag-specific T cell expansion via production of both molecules. Purified splenic Gr-1+ cells included mostly granulocytes at various stages of maturation, as well as monocytes. Activation or recruitment of regulatory Gr-1+ cells was dependent on immunization with CFA. Importantly, these regulatory cells were not detected in draining lymph nodes. These data suggest that innate Gr-1+ splenic cells regulate adaptive immunity. 相似文献
67.
Tarcisio Passos Ribeiro de Campos Bruno M. Mendes Bruno Trindade Wagner L. Araujo 《Reports of Practical Oncology and Radiotherapy》2018,23(5):384-391
Aim
The present study evaluated the increment of cardiac risk (CR) and absorbed dose in radiotherapy of the internal mammary chain (IMC), in particular with photon portals of 4 6?MV, and cobalt therapy (Co60); and, electron portals of 8, 12 and 16?MeV applied in the left breast, considering the adoption of a combined photon (16?Gy) and electron (30?Gy) protocols.Materials and methods
The modified ICRP-reference female model of 60?kg, 163?cm and 43 years of age, coil RCP-AF, was modelled. The MCNP6/SICODES codes were employed, where the spatial dose distributions and dose-volume histograms were generated. Toxicity limits and a CR model were considered.Results
CR associated with the 6?MV, 4?MV and Co60 portals increased 41.1; 40.6 and 34.5%, respectively; while, in 8, 12 and 16?MeV portals, they were 5.0, 32.5 and 49.2%, respectively. High anomalous scatter radiation from electron portals was found in the left lung providing an average dose of 3.3–5.0?Gy.Conclusions
To RCP-AF, the Co60 portal for IMC-RT presented more attractive dose distribution, whose 16?Gy for photon-component produced less CR increase, 5% lower than the other photon portals. Considering electron portals, the smallest CR increase was produced by 8?MeV portal while 12–16?MeV made the risk higher. There is a call for a less hardened energetic spectrum in order to reduce CR; however, holding suitable IMC penetration. A combined Co60/8–12?MeV may bring benefits, reducing CR. The lowest risk was found to 46?Gy electron portals exclusively. 相似文献68.
Zhipeng Wang Lei Xu Han Wang Zhenzhi Li Lu Lu Xiaojia Li Qingyuan Zhang 《Saudi Journal of Biological Sciences》2018,25(5):909-916
The goal of this study was to assess the antitumor efficacy and safety of lobaplatin-based regimens as the second line of treatment in patients with metastatic breast cancer (MBC) resistant to anthracyclines and taxanes, compared with that of cisplatin-based regimens. During August 2012 to April 2015, 87 patients who received lobaplatin-based regimens or cisplatin-based regimens were included. Medical records of the patients noted that lobaplatin (30?mg/m2) or cisplatin (25?mg/m2), combined with another chemotherapeutic agent such as Gemcitabine (1000?mg/m2) or Vinorelbine (25?mg/m2), was intravenously given to the patients on a basis of twenty-one days as one treatment cycle. All the patients were followed until August 2017. The endpoint of this study was progression-free survival (PFS), overall survival (OS), and estimated objective response rate (RR). Safety and drug tolerability data were also obtained. Lobaplatin-based regimens prolonged PFS compared to cisplatin-based regimens (median 13.2 vs 4.7?months, hazard ratio?=?0.37, 95% confidence intervals: 0.21–0.67, P?=?.0007), while OS was not significantly different between the two groups (hazard ratio?=?0.72, 95% confidence intervals: 0.40–1.30, P?=?.2767), as was objective RR (37.8% vs 33.4%, = 0.19, P?=?.6653). Nausea/vomiting and renal injury were more frequent with cisplatin-based regimens. Our results show that lobaplatin-based regimens are superior to cisplatin in terms of efficacy and are better tolerated. 相似文献
69.
本文研究了人工神经网络BP学习算法中动量因子、隐节点数、学习速率、激活因子等对网络学习速度有影响的几个因素,并且找出了最佳值. 相似文献
70.
Summary Two representative cultivars ofCicer arietinum, the desi-type cv.Annigeri and the kabuli-type cv.ICCV6, were regenerated in vitro and clonally propagated from cotyledonary
nodes and meristem tips. The explants were dissected from 1-wk-old seedlings aseptically germinated on WH medium. In both
cultivars, all nodes cultured on B5 medium supplemented with 4.4μM 6-benzylaminopurine developed up to seven shoots per node within 3 wk. Meristem tips were much better suited for multiple
shoot formation. Cultured on DKW-C-a medium supplemented with 4.4μM 6-benzylaminopurine and 0.05μM indole-3-butyric acid, 96% of the meristem tips produced up to 10 shoots per explant. A new method in improving clonal propagation
was subdividing the meristem tips. Doing so, multiple shoot formation was considerably enhanced: up to 90 shoots per original
explant could be obtained with cv.Annigeri, and up to 50 with cv.ICCV6. Indole-3-butyric acid proved to be the best rooting
factor. From several media tested, the best root induction and development was achieved on WH medium supplemented with 2.5μ M indole-3-butyric acid: 72% rooting with cv.Annigeri and 68% rooting with cv.ICCV6. With both cultivars there were no differences
in rooting capacity between shoots of nodal origin and those derived from meristem tips. The plantlets obtained were transferred
into soil and kept under greenhouse conditions. The survival frequency was 28% with cv.Annigeri and 23% with cv.ICCV6. R0 plants remained smaller than seed-grown controls and produced only a few fertile seeds. There was no difference between R1 plants and controls in growth, development, and seed set. 相似文献