Ring opening polymerization of lactides and lactones by multimetallic alkyl zinc complexes derived from the acids Ph₂C(X)CO₂2H (X = OH, NH₂ )

The reaction of the dialkylzinc reagents R₂Zn with the acids 2,2-Ph₂C(X)(CO₂H), where X = NH₂, OH, i.e. 2,2′-diphenylglycine (dpgH) or benzilic acid (benzH2), in toluene at reflux temperature afforded the tetra-nuclear ring complexes [RZn(dpg)]₄, where R = Me (1), Et (2), 2-CF₃C₆H₄ (3), and 2,4,6-F₃C₆H₂ (4); complex 2 has been previously reported. The crystal structures of 1·(2MeCN), 3 and 4·(4(C₇H₈)·1.59(H₂O)) are reported, along with that of the intermediate compound (2-CF₃C₆H₄)3B·MeCN and the known compound [ZnCl₂(NCMe)₂]. Complexes 1–4, together with the known complex [(ZnEt)₃(ZnL)₃(benz)₃] (5; L = MeCN), have been screened, in the absence of benzyl alcohol, for their potential to act as catalysts for the ring opening polymerization (ROP) of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL) and rac-lactide (rac-LA); the co-polymerization of ε-CL with rac-LA was also studied. Complexes 3 and 4 bearing fluorinated aryls at zinc were found to afford the highest activities

Human capital and entrepreneurial success : a meta-analytical review

The study meta-analytically integrates results from three decades of human capital research in entrepreneurship. Based on 70 independent samples (N = 24,733), we found a significant but small relationship between human capital and success (r(c) = .098). We examined theoretically derived moderators of this relationship referring to conceptualizations of human capital, to context, and to measurement of success. The relationship was higher for outcomes of human capital investments (knowledge/skills) than for human capital investments (education/experience), for human capital with high task-relatedness compared to low task-relatedness, for young businesses compared to old businesses, and for the dependent variable size compared to growth or profitability. Findings are relevant for practitioners (lenders, policy makers, educators) and for future research. Our findings show that future research should pursue moderator approaches to study the effects of human capital on success. Further, human capital is most important if it is task-related and if it consists of outcomes of human capital investments rather than human capital investments; this suggests that research should overcome a static view of human capital and should rather investigate the processes of learning, knowledge acquisition, and the transfer of knowledge to entrepreneurial tasks

Strategies, Uncertainty and Performance of Small Business Startups

Personal strategies of owners/founders of small business startups are related to performance and to environmental uncertainty. This is done using a longitudinal data set of some 50 Dutch startups. The results suggest a dynamic process between strategy and performance.A discrimination is made between four strategies (reactive, critical point, complete planning and opportunistic). The role of uncertainty is discussed. The dynamic process is embedded in the PERSUADE model.entrepreneurship;strategy;uncertainty;performance;small business startups

Thoroughbred mare's milk exhibits a unique and diverse free oligosaccharide profile.

The Thoroughbred is among the most valuable horse breeds, and its husbandry is a major industry. Mare's milk plays a major role in the health of neonatal foals. Although the main components of mare's milk are broadly characterized, free oligosaccharides (OS), which possess various bioactivities in many mammalian milks, have not been fully profiled in Thoroughbreds. The aim of this study was to identify and quantify OS in Thoroughbred mare's milk during the first week of lactation, when foals typically consume mare's milk exclusively. A total of 48 OS structures (including isomers and anomers), corresponding to 20 unique compositions, were identified by nano LC-Chip QToF-MS and confirmed by tandem mass spectrometry. Neutral OS were the most abundant glycans (58.3%), followed by acidic OS containing Neu5Ac (33.3%), a minor presence of fucosylated OS structures (6.25%) and one structure containing NeuGc (2.1%). Comparison with other well-characterized mammalian milks revealed that mare's milk shared 8 OS structures with human, bovine, pig and goat milk (i.e., 2 sialyllactose isomers, 3 hexose, LNH, LNT, and OS with the composition 3 Hex-1 Neu5Ac). Additionally, there were seven unique OS not previously found in other mammal milks. During the first 7 days of lactation, the percentage of neutral and fucosylated OS increased, whereas acidic OS decreased and the total OS concentration ranged from 217.8 mg·L-1 to 79.8 mg·L-1

Impact of humidity on latent print processing and recovery

The goal of this study was to determine if environmental factors impact the quality of detail in latent prints on non-porous and porous surfaces. Specifically, this study focused on how humidity impacts latent print processing, development, and analysis on tile and paper. Latent prints are prints deposited on surfaces in sweat (James, Nordby & Bell, 2014). As humidity is water vapor in the air, it is expected that increased humidity would have a noticeable impact on the quality of latent prints. To date, no research has been conducted comparing how humidity impacts latent prints on porous and non-porous surfaces at consistent temperatures. In this study, latent prints were deposited on a non-porous surface (white tile) and a porous surface (paper) and subjected to 30%, 50% and 90% humidity at a consistent temperature range (70-74 degrees Fahrenheit) to assess if humidity causes a noticeable change in the quality of latent prints. Once collected, prints were uploaded into the Automated Fingerprint Identification System (AFIS), which was set to automatically mark minutiae. Minutiae were then edited by an experienced latent fingerprint examiner to ensure accuracy. The edited minutiae count generated from AFIS was used to determine what category each print fell under: low quality (0-6 minutiae), moderate quality (7-12 minutiae), or high quality (13 and above minutiae). Multiple statistical tests were performed to determine statistical significance between different variables. This included comparing tracked humidities, tracked temperature ranges, overall minutiae count between humidities, and change in minutiae count over time. Based on the results, humidity did appear to have an impact on the quality of the prints over time for both surfaces, porous and non-porous. Overall, quality decreased with increased levels of humidity. At each humidity, a decrease in quality was also observed over time. The only prints that deviated from this were the prints on the tile at 90% humidity tile. These prints stayed at a consistent low quality. This leads to the conclusion that prints recovered on white tile with black powder and prints recovered on paper with ninhydrin decrease in quality with increased levels of humidity and also decrease over time at set humidities