Performance of columns packed with the new shell particles, Kinetex-C18

The performance of the new Kinetex-C₁₈ column was investigated. Packed with a new brand of porous shell particles, this column has an outstanding efficiency. Once corrected for the contribution of the instrument extra column volume, the minimum values of the reduced plate heights for a number of low molecular weight compounds (e.g., anthracene and naphtho[2,3-a]pyrene) were between 1.0 and 1.3, breaking the legendary record set 3 years ago by Halo-C₁₈ packed columns. The liquid-solid mass transfer of proteins (e.g., insulin and lyzozyme) is exceptionally fast on Kinetex-C₁₈ much faster than on the Halo-C₁₈ column. The different contributions of dispersion and mass transfer resistances to the column efficiency were determined and discussed. The possible reasons for this extremely high column efficiency are discussed.

An illumination invariant face recognition system for access control using video

Illumination and pose invariance are the most challenging aspects of face recognition. In this paper we describe a fully automatic face recognition system that uses video information to achieve illumination and pose robustness. In the proposed method, highly nonlinear manifolds of face motion are approximated using three Gaussian pose clusters. Pose robustness is achieved by comparing the corresponding pose clusters and probabilistically combining the results to derive a measure of similarity between two manifolds. Illumination is normalized on a per-pose basis. Region-based gamma intensity correction is used to correct for coarse illumination changes, while further refinement is achieved by combining a learnt linear manifold of illumination variation with constraints on face pattern distribution, derived from video. Comparative experimental evaluation is presented and the proposed method is shown to greatly outperform state-of-the-art algorithms. Consistent recognition rates of 94-100% are achieved across dramatic changes in illumination.

Retention divergence of terpenes with porous graphitized carbon and C18 stationary phases

The significant divergence between the retention of 16 terpene standards on porous graphitized carbon (PGC) and C18 packing materials are illustrated. The PGC surface is shown to provide a selectivity toward shape, polarity, and structure that is not afforded by the C18 surface. This observation is illustrated by plots of the retention factors similar to those typically used to represent 2D-HPLC separations. A geometric approach to factor analysis was used to measure the separation divergence together with the selectivity and the product selectivity factors of closely related species. When a methanol mobile phase was used with the PGC surface, a large fraction of the separation space could be utilized. That is further reflected by a spreading angle of 80.3°. The PGC material was also successful at resolving structural isomers where the C18 phase was not. It was also found that the choice of the mobile phase is important when using this material. A much larger degree of space utilization was seen with methanol than with acetonitrile that displayed a spreading angle of only 40.8°.

Differential (18)F-FDG and 3'-deoxy-3'-(18)F-fluorothymidine PET responses to pharmacologic inhibition of the c-MET receptor in preclinical tumor models.

The ability of PET to image functional changes in tumors is increasingly being used to evaluate response and predict clinical benefit to conventional and novel cancer therapies. Although the use of (18)F-FDG PET is well established, 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET has potential advantages as a more specific marker of cellular proliferation. c-MET signaling is frequently dysregulated in cancer and is therefore an attractive therapeutic target. Crizotinib (PF-2341066) is a novel adenosine triphosphate-competitive c-MET kinase inhibitor with antitumor activity in a range of tumor models. The aim of this study was to investigate the utility of PET of glucose metabolism and cell proliferation to monitor tumor response to crizotinib in 2 cell lines with aberrant c-MET signaling.

Incorporation of group 14 elements into siloxane-bridged paracyclophanes cyclo-[p,p´-Me2SiC6H4EMe2C6H4SiMe2O]2 (E = C, Si, Ge, Sn)§

The bis(arylene silanes) p,p'-HMe₂SiC₆H₄EMe₂C₆H₄SiMe₂H (E = C (10), Si (11), Ge (12), Sn(13)) were prepared by the in situ Grignard reaction of p,p'-BrC₆H₄CMe₂C₆H₄Br, Mg turnings, and HSiMe₂Cl (for 10) and the Grignard reaction using p-HMe₂SiC₆H₄Br, Mg turnings, and Me₂ECl₂ (E = Si for 11, Ge for 12, Sn for 13). The oxidation of 10-13 using Pearlman's catalyst, Pd(OH)₂/C, in aqueous THF provided the bis(arylene silanols) p,p'-HOMe₂SiC₆H₄EMe₂C₆H₄SiMe₂OH (E = C (14), Si (15), Ge (16), Sn(17)). The HCl-catalyzed condensation of 14-17 in highly diluted solutions of acetone/water afforded the siloxane-bridged paracyclophanes cyclo-[p,p'-Me₂SiC₆H₄EMe₂C₆H₄SiMe₂O]₂ (6-9) that incorporate the group 14 elements E = C, Si, Ge, and Sn. Compounds 6-17 were investigated by multinuclear solution and solid-state NMR spectroscopy and 6 and 9 also by X-ray crystallography.

Sequential 123-I-iododexetimide scans in temporal lobe epilepsy: comparison with neuroimaging scans (MR imaging and 18-F-FDG-PET imaging)

Purpose Muscarinic acetylcholine receptors (mAChRs) play an important role in the generation of seizures. Single-photon emission computed tomography (SPECT) with ¹²³I-iododexetimide (IDEX) depicts tracer uptake by mAChRs. Our aims were to: (a) determine the optimum time for interictal IDEX SPECT imaging; (b) determine the accuracy of IDEX scans in the localisation of seizure foci when compared with video EEG and MR imaging in patients with temporal lobe epilepsy (TLE); (c) characterise the distribution of IDEX binding in the temporal lobes and (d) compare IDEX SPECT and ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in identifying seizure foci.
Methods We performed sequential scans using IDEX SPECT imaging at 0, 3, 6 and 24 h in 12 consecutive patients with refractory TLE undergoing assessment for epilepsy surgery. Visual and region of interest analyses of the mesial, lateral and polar regions of the temporal lobes were used to compare IDEX SPECT, FDG PET and MR imaging in seizure onset localisation.
Results The 6-h IDEX scan (92%; κappa=0.83, p=0.003) was superior to the 0-h (36%; kappa=0.01, p>0.05), 3-h (55%;κappa=0.13, p>0.05) and 24-h IDEX scans in identifying the temporal lobe of seizure origin. The 6-h IDEX scan correctly predicted the temporal lobe of seizure origin in two patients who required intracranial EEG recordings to define the seizure onset. Reduced ligand binding was most marked at the temporal pole and mesial temporal structures. IDEX SPECT was superior to interictal FDG PET (75%; κappa=0.66, p=0.023) in seizure onset localisation. MR imaging was non-localising in two patients in whom it was normal and in another patient in whom there was bilateral symmetrical hippocampal atrophy.
Conclusion The 6-h IDEX SPECT scan is a viable alternative to FDG PET imaging in seizure onset localisation in TLE.

Solubility and Stability of cytochrome c in hydrated ionic liquids : effect of oxo acid residues and kosmotropicity

Hydrated ionic liquids (ILs) were prepared by adding appropriate amounts of water to hydrophilic ILs. Some hydrated ILs show excellent solubilizing ability for proteins, keeping the basic properties of ILs. The solubility of cytochrome c (cyt c) depended on the structure of the component ions. When component anions have oxo acid residues, the resulting hydrated ILs solubilize cyt c quite well. In such hydrated ILs, the structure and activity of cyt c is influenced by the kosmotropicity of the component ions. We synthesized ILs from various ions having different kosmotropicity, including dihydrogen phosphate (dhp), dibutylphosphate, acetate, lactate, and methanesulfonate as anions. The activity of the dissolved cyt c depends on the permutations of kosmotropicity of the component ions. cyt c shows no structural change and retains its activity when dissolved in the hydrated choline dhp, which is an excellent combination of chaotropic cation and kosmotropic anion. Furthermore, cyt c dissolved in the hydrated choline dhp remained in a native state and was active after 18 months of storage at room temperature.

Short-term intensified cycle training alters acute and chronic responses of PGC1α and cytochrome C oxidase IV to exercise in human skeletal muscle

Reduced activation of exercise responsive signalling pathways have been reported in response to acute exercise after training; however little is known about the adaptive responses of the mitochondria. Accordingly, we investigated changes in mitochondrial gene expression and protein abundance in response to the same acute exercise before and after 10-d of intensive cycle training.

Nine untrained, healthy participants (mean±SD; VO2peak 44.1±17.6 ml/kg/min) performed a 60 min bout of cycling exercise at 164±18 W (72% of pre-training VO2peak). Muscle biopsies were obtained from the vastus lateralis muscle at rest, immediately and 3 h after exercise. The participants then underwent 10-d of cycle training which included four high-intensity interval training sessions (6×5 min; 90–100% VO2peak) and six prolonged moderate-intensity sessions (45–90 min; 75% VO2peak). Participants repeated the pre-training exercise trial at the same absolute work load (64% of pre-training VO2peak). Muscle PGC1-α mRNA expression was attenuated as it increased by 11- and 4- fold (P<0.001) after exercise pre- and post-training, respectively. PGC1-α protein expression increased 1.5 fold (P<0.05) in response to exercise pre-training with no further increases after the post-training exercise bout. RIP140 protein abundance was responsive to acute exercise only (P<0.01). COXIV mRNA (1.6 fold; P<0.01) and COXIV protein expression (1.5 fold; P<0.05) were increased by training but COXIV protein expression was decreased (20%; P<0.01) by acute exercise pre- and post-training.

These findings demonstrate that short-term intensified training promotes increased mitochondrial gene expression and protein abundance. Furthermore, acute indicators of exercise-induced mitochondrial adaptation appear to be blunted in response to exercise at the same absolute intensity following short-term training.

(1)H-NMR analysis of the human urinary metabolome in response to an 18-month multi-component exercise program and calcium-vitamin-D3 supplementation in older men

The musculoskeletal benefits of calcium and vitamin-D3 supplementation and exercise have been extensively studied, but the effect on metabolism remains contentious. Urine samples were analyzed by (1)H-NMR spectroscopy from participants recruited for an 18-month, randomized controlled trial of a multi-component exercise program and calcium and vitamin-D3 fortified milk consumption. It was shown previously that no increase in musculoskeletal composition was observed for participants assigned to the calcium and vitamin-D3 intervention, but exercise resulted in increased bone mineral density, total lean body mass, and muscle strength. Retrospective metabolomics analysis of urine samples from patients involved in this study revealed no distinct changes in the urinary metabolome in response to the calcium and vitamin-D3 intervention, but significant changes followed the exercise intervention, notably a reduction in creatinine and an increase in choline, guanidinoacetate, and hypoxanthine (p < 0.001, fold change > 1.5). These metabolites are intrinsically involved in anaerobic ATP synthesis, intracellular buffering, and methyl-balance regulation. The exercise intervention had a marked effect on the urine metabolome and markers of muscle turnover but none of these metabolites were obvious markers of bone turnover. Measurement of specific urinary exercise biomarkers may provide a basis for monitoring performance and metabolic response to exercise regimes.