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Tuning of preparation conditions, such as variations in the amount of a porogen, concentration of an aqueous acid catalyst, and adjustment in polymerization temperature and time, towards optimized chromatographic performance of thermally polymerized monolithic capillaries prepared from 3-(methacryloyloxy)propyltrimethoxysilane has been carried out. Performance of capillary columns in reversed-phase liquid chromatography was assessed utilizing various sets of solutes. Results describing hydrophobicity, steric selectivity, and extent of hydrogen bonding enabled comparison of performance of hybrid monolithic columns prepared under thermal (TSG) and photopolymerized (PSG) conditions. Reduced amounts of porogen in the polymerization mixture, and prolonged reaction times were necessary for the preparation of monolithic columns with enhanced retention and column efficiency that reached to 111,000 plates/m for alkylbenzenes with shorter alkyl chains. Both increased concentration of catalyst and higher temperature resulted in faster polymerization but inevitably in insufficient time for pore formation. Thermally polymerized monoliths produced surfaces, which were slightly more hydrophobic (a methylene selectivity of 1.28±0.002 TSG vs 1.20±0.002 PSG), with reduced number of residual silanols (a caffeine/phenol selectivity of 0.13±0.001 TSG vs 0.17±0.003 PSG). However, steric selectivity of 1.70±0.01 was the same for both types of columns. The batch-to-batch repeatability was better using thermal initiation compared to monolithic columns prepared under photopolymerized conditions. RSD for retention factor of benzene was 3.7% for TSG capillaries (n=42) vs. 6.6% for PSG capillaries (n=18). A similar trend was observed for columns prepared within the same batch., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Porous hybrid organo-silica monoliths have been prepared inside pretreated 100 μm id UV transparent fused-silica capillaries using simultaneous sol-gel transition and polymerization of 3-(methacryloyloxy)propyl trimethoxysilane in the presence of toluene as a porogen. The sol-gel reaction was catalyzed by hydrochloric acid while various photoinitiators including azobisisobutyronitrile, 2,2-dimethoxy-2-phenylacetophenone, and Irgacure 819 were used for the photopolymerization carried out under irradiation with UV light at a wavelength of 254 or 365 nm. The chromatographic performance of photopolymerized monolithic columns in RP liquid chromatographic mode was assessed with respect to the following metrics: column efficiency, methylene and steric selectivity, effect of silanol groups, van Deemter plot, permeability, and pore size distribution. Columns with an efficiency of up to 77 000 plates/m for benzene has been achieved at a flow velocity of 0.47 mm/s. The performance of photopolymerized hybrid monolithic column was compared to the performance of columns prepared via thermally initiated polymerization., (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Anterior-posterior (AP) knee laxity after anterior cruciate ligament (ACL) reconstruction may differ between sexes for different graft types. Females may experience an increase in AP knee laxity following an ACL reconstruction with a hamstrings graft, which is not seen in males with a hamstrings graft or in males or females with a bone-patellar tendon-bone (BTB) graft. The hypothesis of this review is sex differences in AP knee laxity and this will be identified in patients who undergo an ACL reconstruction with a hamstrings graft, while no sex differences will be observed in patients who have an ACL reconstruction with a BTB graft. A systematic search was performed in PubMed, CINAHL and SPORTDiscus. Inclusion criteria were articles published in the English language that studied human subjects who underwent an ACL reconstruction with a BTB or hamstrings autograft, and the presence of a sex comparison on outcome measures including side-to-side difference in AP knee laxity. Methodological quality was assessed using a Modified Coleman Methodology Score. Eleven cohort studies met the inclusion criteria. Six investigated sex differences in both hamstrings and BTB grafts. Three only investigated BTB grafts and two only investigated hamstrings grafts. These studies consistently reported increases in AP knee laxity in females after an ACL reconstruction with a hamstrings graft that was not observed in the other cohorts. This systematic review indicates that female patients have greater AP knee laxity following an ACL reconstruction with a hamstrings autograft compared with males with a similar procedure, and both females and males following an ACL reconstruction with a BTB autograft. These results are derived from lower level evidence, as no randomized control trials have attempted to answer this question. Future studies need to rigorously address this clinical question to confirm the results currently in the literature.