Mineral fabrication and golgi apparatus activity in the mouse calvarium

There is diverse opinion about the mechanism of bone mineralization with only intermittent reports of any direct organellar role played by the golgi apparatus (juxtanuclear body). Light and laser confocal microscopy was combined with electron microscopy and elemental EDX (energy dispersive X-ray microanalysis) in comparing “young” osteocytes in situ in fresh and “slam” frozen developing mouse calvarium, with similar cells (MC3T3-E1) maintained in vitro. The distribution of “nascent” electron dense mineral was examined histochemically (von Kossa, GBHA), including tetracycline (TC) staining as a fluorescent complex with bone salt, while golgi body activity was demonstrated by transfection with a specific green fluorescent construct (GFP/mannosidase II). In tissue culture golgi body activity and mineralization were both blocked by brefeldin A (an established golgi inhibitor) and restored by forskolin, enabling an association with mineral fabrication to be quantified as changing fluorescence intensity (AU) of GFP or TC markers. Results from osteocytes in situ supported previous descriptions of intracellular electron dense objects (microspheres and nanospheres) in a juxtanuclear pattern, containing Ca, P and transitory Si, in a spectrum recapitulated in the calcifying culture after 10 days, when GFP fluorophore surged from 71.7 ± 1.4SD to 133.7 ± 2.7SD AU by 14 days (p < 0.0001). At this stage TC fluorophore mean intensity was 23.8 ± 3.7SD AU (14 days) rising to 45.0 ± 5.1SD AU by 17 days, compared to its stationary 21.7 ± 3.6SD when treated 3 days previously with BFA golgi inhibitor (p < 0.0001), until forskolin reversal. It was concluded from the changing juxtanuclear morphology, Si mineralization mediation and the variably controlled activity versus stasis that the inorganic phase of bone is a complex golgi-directed fabrication with implications for bone matrix biology and evolution

Water-Film Cooling of an 80 deg Total-Angle Cone at a Mach Number of 2 for Airstream Total Temperatures up to 3,000 deg R

Film-cooling tests, with water as the coolant, were made on an 80 deg total-angle cone in a Mach number 2 free jet at sea-level pressure. The tests were made at free-stream total temperatures from 1,500 deg R to 3,000 deg R and at free-stream Reynolds numbers per foot from 8 x 10(exp 6) to 3 x 10(exp 6). The tests showed that the downstream end of the model became very hot if the coolant rate was too small to cover the complete model with a water film. This water film was fairly symmetrical when the model was at zero angle of attack but was very asymmetrical when the model was at an angle of attack of 5 deg. A comparison with results of a previous transpiration-cooling test showed that, with water as the coolant, transpiration cooling was at least 2.5 times as efficient as the film cooling of the present tests

Capital Acquisition Attitudes: Gender and Experience

In this research we provide evidence on small firm owners\u27 attitudes and approaches to capital acquisition. The most surprising finding is their general dissatisfaction with the capital acquisition process. Yet we found no evidence that this dissatisfaction translates into poor performance. Our analysis indicates that male-owned business were older, more likely to be technology-based, and bigger in terms of sales and assets. Male respondents were also better educated. We found no significant results for the firms owned by more experienced respondents. However, more experienced owners and male respondents were more likely to look outside resources, like governments, to provide guidance and assistance in the capital acquisition process. Implications from the results can be used by owners to better understand capital acquisition decisions and to develop better capital acquisition, by government agencies that develop public policy on small firms, and consultants that assist small firms with capital acquisition

Library Faculty Publishing and Intellectual Property Issues: A Survey of Attitudes and Awareness

Researchers from Southern Illinois University Carbondale (SIUC) surveyed faculty members from 10 academic research libraries to learn about scholarly publishing activities, attitudes, and policies. Areas of special interest included the effect of publishers’ intellectual property policies and institutional promotion and tenure processes on library faculty publishing decisions. The library faculty members were also asked about their experience in negotiating for additional rights from publishers and their experience in self-archiving their research. The researchers wanted to determine if there were any correlation between a library faculty member’s rank and tenure status and the number of peer-reviewed articles published in refereed journals

Effect of Professional Background on Venture Capital Proposal Evaluation

This paper reports on the differences in investment related activities and evaluation criteria of venture capitalists having a business background compared to venture capitalists having a non-business background . Data was collected from a nationwide survey of 72 venture capitalists. The results show that venture capitalists having a non-business background invest in earlier stages of the firm. require a shorter payback period and make more follow-up investments than business background venture capitalists. The non-business background venture capitalists place greater importance on the uniqueness of the product , the cost structure of the project and the entrepreneur\u27 s health and less importance on exit procedures than business background venture capitalists