我国物流企业全要素生产效率分析

为分析我国物流企业生产效率的发展情况,本文以我国8家上市物流企业为例,利用DEA Malmquist生产效率变化指数对它们在2001～2006年的全要素生产效率进行分析.通过分析发现,我国物流企业的生产效率发展趋势较好,呈上升状态,但上升程度并不明显,其中技术效率和技术有所下滑,而规模效率则有所上升.同时结合了企业组织形式、资源配置及发展战略等内部因素和国内外经济发展环境、国家产业发展政策与法规等外部因素对各个企业和它们的整体生产效率发展过程进行了分析和说明,提出了解决我国物流企业生产效率偏低的途径,为政府决策者和物流企业管理者提供了科学决策的依据.     

Molecular cloning of cDNA for murine interleukin-3

The cDNA sequence for murine interleukin-3, one of the colony stimulating factors that regulate haematopoiesis, codes for a polypeptide of 166 amino acids including a putative signal peptide. The predicted amino acid sequence indicates that formation of mature interleukin-3 involves proteolytic removal of not only the signal peptide but additional amino-terminal amino acids.     

Olfactory ensheathing cells promote neurite sprouting of injured axons in vitro by direct cellular contact and secretion of soluble factors

Olfactory ensheathing cells (OECs) represent an exciting possibility for promoting axonal regeneration within the injured spinal cord. A number of studies have indicated the ability of these cells to promote significant reactive sprouting of injured axons within the injured spinal cord, and in some cases restoration of functional abilities. However, the cellular and/or molecular mechanisms OECs use to achieve this are unclear. To investigate such mechanisms, we report for the first time the ability of OECs to promote post-injury neurite sprouting in an in vitro model of axonal injury. Using this model, we were able to differentiate between the direct and indirect mechanisms underlying the ability of OECs to promote neuronal recovery from injury. We noted that OECs appeared to act as a physical substrate for the growth of post-injury neurite sprouts. We also found that while post-injury sprouting was promoted most when OECs were allowed to directly contact injured neurons, physical separation using tissue culture inserts (1 mm pore size, permeable to diffusible factors but not cells) did not completely block the promoting properties of OECs, suggesting that they also secrete soluble factors which aid post-injury neurite sprouting. Furthermore, this in vitro model allowed direct observation of the cellular interactions between OECs and sprouting neurites using live-cell-imaging techniques. In summary, we found that OECs separately promote neurite sprouting by providing a physical substrate for growth and through the expression of soluble factors. Our findings provide new insight into the ability of OECs to promote axonal regeneration, and also indicate potential targets for manipulation of these cells to enhance their restorative ability.Received 19 January 2004; received after revision 8 March 2004: accepted 17 March 2004