Technical note: Rapid mineral determination in forages by X-ray fluorescence.

A large portion of the cow's ration is composed of forages that can vary greatly in mineral concentrations, which may affect animal performance and health. Current methods for mineral analysis require sample destruction either through wet or dry ashing and complex analytical techniques for individual minerals. Energy dispersive X-ray fluorescence (EDXRF) is a nondestructive, multi-mineral, spectroscopy technique, which makes mineral quantification simple, direct, and affordable. The study objective was to evaluate the prediction performance of EDXRF of Na, Mg, P, S, Cl, Ca, K, Mn, Fe, Cu, and Zn concentrations in forages. Twelve certified plant samples with a wide range in mineral concentrations were used to develop calibrations, and 35 forages (18 alfalfa hays, 10 grass hays, 7 corn silages) with measured mineral concentrations, which were collected over several years from 3 proficiency programs, were used as an independent validation set. All the samples were previously dried and finely ground and were prepared by compressing them into a round dense pellet, 40 mm in diameter, using a 40-ton pneumatic laboratory press. Samples were scanned using an EDXRF instrument enhanced for lighter minerals like Na and Mg. Samples were scanned at 20 keV and at 40 KeV associated with an Al filter, for a total analysis time of approximately 6 min. Calibrations were developed with Bruker SpectraEDX (Bruker, Hamburg, Germany) software and optimized to minimize the standard error of calibration. All of the minerals had acceptable calibration performance with coefficient of determination ranging from 0.93 (P) and 0.99 (Cl, Ca, and Mn) and coefficients of variation within 5 to 14%, which are similar to the coefficients of variation of the reference analysis. The coefficients of variation for Na was an exception, with a coefficients of variation of 29%. The validation set obtained similar statistical results as that observed in calibration. The root mean square error of prediction corrected for bias was similar to the standard error of calibration, indicating that it is possible to build a robust calibrations that performed well across different type of forages by using 12 reference samples with a sufficient range in mineral concentrations that were determined accurately. A bias correction was necessary to improve prediction accuracy only for K (-0.23% dry matter) and Ca (-0.16% dry matter). Energy dispersive X-ray fluorescence demonstrated the ability to be an accurate, direct, and simple technique for forage mineral analysis.

Tetrasubstituted cyclopentadienones as suitable enantiopure ligands with axial chirality.

A series of thermally stable atropisomeric phencyclone ligands (ΔG > 35 kcal mol-1), bearing two chiral axes, has been successfully synthesized, taking into account the results of DFT calculations on model systems. The absolute configurations of the novel atropisomers have been assigned using TD-DFT simulation of ECD spectra. Atropisomeric phencyclones herein presented pave the way towards new ruthenium-based enantioselective hydrogenation catalysts.

Mid-infrared coincidence measurements on twin photons at room temperature.

Quantum measurements using single-photon detectors are opening interesting new perspectives in diverse fields such as remote sensing, quantum cryptography and quantum computing. A particularly demanding class of applications relies on the simultaneous detection of correlated single photons. In the visible and near infrared wavelength ranges suitable single-photon detectors do exist. However, low detector quantum efficiency or excessive noise has hampered their mid-infrared (MIR) counterpart. Fast and highly efficient single-photon detectors are thus highly sought after for MIR applications. Here we pave the way to quantum measurements in the MIR by the demonstration of a room temperature coincidence measurement with non-degenerate twin photons at about 3.1 µm. The experiment is based on the spectral translation of MIR radiation into the visible region, by means of efficient up-converter modules. The up-converted pairs are then detected with low-noise silicon avalanche photodiodes without the need for cryogenic cooling.

Atropisomerism in 3-arylthiazolidine-2-thiones. A combined dynamic NMR and dynamic HPLC study.

Sterically hindered 3-arylthiazolidine-2-thiones were prepared by a solvent-free reaction with arylisothiocyanates and 1,4-dithiane-2,5-diol. Atropisomerism was observed in two compounds (3 and 4, aryl = 1-naphthyl and 2-methylnaphth-1-yl), whose rotational energy barriers were measured using dynamic NMR and dynamic HPLC. The experimental analyses were supported by DFT calculations. Thermally stable atropisomers were obtained by dehydration of compounds 3 and 4 and the absolute configuration of the atropisomers of compound 6 was determined by theoretical simulation of the ECD and VCD spectra.

High-frequency electro-optic measurement of strained silicon racetrack resonators.

The observation of the electro-optic effect in strained silicon waveguides has been considered a direct manifestation of an induced χ(2) nonlinearity in the material. In this work, we perform high-frequency measurements on strained silicon racetrack resonators. Strain is controlled by a mechanical deformation of the waveguide. It is shown that any optical modulation vanishes, independent of the applied strain, when the applied voltage varies much faster than the carrier effective lifetime and that the DC modulation is also largely independent of the applied strain. This demonstrates that plasma carrier dispersion is responsible for the observed electro-optic effect. After normalizing out free-carrier effects, our results set an upper limit of (8±3) pm/V to the induced high-speed effective χeff,zzz(2) tensor element at an applied stress of -0.5 GPa. This upper limit is about 1 order of magnitude lower than previously reported values for static electro-optic measurements.

Chaotic dynamics in coupled resonator sequences.

Optically induced thermal and free carrier nonlinearities in silicon micro-ring resonator influence their behavior. They can be either deleterious by making them instable and by driving their resonances out of the designed wavelengths, or enabler of different applications. Among the most interesting one, there are optical bistability and self induced oscillations. These lead to all optical logic, signal modulation, optical memories and applications in neural networks. Here, we theoretically and experimentally demonstrate that when many resonators are coupled together, thermal and free carrier nonlinearities induce also chaos. The chaotic dynamics are deeply analyzed using experimentally reconstructed phase space trajectories and the tool of Lyapunov exponents.

Reconfigurable optical routers based on Coupled Resonator Induced Transparency resonances.

The interferometric coupling of pairs of resonators in a resonator sequence generates coupled ring induced transparency (CRIT) resonances. These have quality factors an order of magnitude greater than those of single resonators. We show that it is possible to engineer CRIT resonances in tapered SCISSOR (Side Coupled Integrated Space Sequence of Resonator) to realize fast and efficient reconfigurable optical switches and routers handling several channels while keeping single channel addressing capabilities. Tapered SCISSORs are fabricated in silicon-on-insulator technology. Furthermore, tapered SCISSORs show multiple-channel switching behavior that can be exploited in DWDM applications.

Coupled-resonator-induced-transparency concept for wavelength routing applications.

The presence of coupled resonators induced transparency (CRIT) effects in side-coupled integrated spaced sequence of resonators (SCISSOR) of different radii has been studied. By controlling the rings radii and their center to center distance, it is possible to form transmission channels within the SCISSOR stop-band. Two different methods to exploit the CRIT effect in add/drop filters are proposed. Their performances, e. g. linewidth, crosstalk and losses, are examined also for random variations in the structural parameters. Finally, few examples of high performances mux/demux structures and 2 × 2 routers based on these modified SCISSOR are presented. CRIT based SCISSOR optical devices are particularly promising for ultra-dense wavelength division multiplexing applications.

Robust design of an optical router based on a tapered side-coupled integrated spaced sequence of optical resonators.

A novel (to our knowledge) scheme of an optical router/switch element, composed of a tapered side-coupled integrated spaced sequence of optical resonators, is proposed. It is based on a modified design of the ring sequence in which the resonance conditions are set by the single ring resonance and by the coherent feedback of the sequence of rings. This double condition yields robustness against fabrication defects, dense routing capability, and high switching efficiency.

Analytical identification of additional impurities in urinary-derived gonadotrophins.

Advances in proteomic technology have enabled contaminant proteins to be identified from complex protein mixtures. The purity of two purified urinary gonadotrophin products, human menopausal gonadotrophin (u-HMG) and human FSH (u-hFSH), was compared with a preparation of recombinant human FSH (r-hFSH). After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), western blot analysis showed that the recombinant preparation contained only FSH, whereas the urine-derived preparations exhibited several non-FSH or LH-related bands. These urinary components were further investigated by a proteomic approach using two-dimensional SDS-PAGE followed by mass spectrometric identification. The proteomic approach detected a total of 23 non-gonadotrophin-related proteins, at variable levels in different batches of the urine-derived preparations. Of these, 16 co-purified proteins have not been previously reported to be present in urine-derived gonadotrophins. These results indicate that the process used to purify urinary gonadotrophins may not remove all non-gonadotrophin proteins. By using a comprehensive proteomic approach, it has been shown that the recombinant FSH preparation has greater purity than either of the urine-derived preparations.

Comparative assessment of the consistency and quality of a highly purified FSH extracted from human urine (urofollitropin) and a recombinant human FSH (follitropin alpha).

The revolutionary development of biotechnology-derived therapeutic proteins has provided the expected improvements in quality, purity and consistency, as demonstrated in recombinant human FSH (rhFSH). However, the development of urine-derived gonadotrophins has not always shown comparable improvements. More recently, highly purified urine-derived FSH (uFSH-HP) products have become widely available. The relative purity, level of urine-derived contaminants, and consistency of one such highly purified human uFSH (uhFSH) (urofollitropin) has been assessed and directly compared with rhFSH (follitropin alpha). It has been demonstrated that the highly purified urofollitropin contains variable levels of urine-derived contaminant proteins and demonstrates a variable level of FSH purity, FSH isoforms, and delivered dose. These variable factors may contribute to the control of ovarian stimulation. The relative purity, variable consistency and the presence of contaminants indicates that the urofollitropin is, at best, a partially purified uFSH that is not able to meet the quality attributes of follitropin alpha (rhFSH).

Comparative characterisation of a commercial human chorionic gonadotrophin extracted from human urine with a commercial recombinant human chorionic gonadotrophin.

BACKGROUND: A commercial preparation of recombinant human chorionic gonadotrophin (r-hCG, Ovitrelle) was launched in 2001. Generally, hCG is available in two formats: human chorionic gonadotrophin (u-hCG), derived from the urine of pregnant females, and r-hCG produced by DNA based biotechnology. METHOD: The analytical characteristics of a highly purified u-hCG (Gonasi HP) were assessed and compared, for the first time, with the recombinant derived r-hCG (Ovitrelle). Gonasi HP is produced by extracting and purifying hCG from urine to obtain a specific bioactivity of 5000 IU/mg protein. Ovitrelle is produced via a recombinant derived mammalian cell line and purified to obtain a specific activity of 26 000 IU/mg. RESULTS AND CONCLUSION: It has been documented that commercially available u-hCG preparations can contain a number of urine derived protein contaminants as well as hCG related metabolites. This is also the case for Gonasi HP, where hCG related molecules and other proteins were found to be present, including epidermal growth factor (EGF) and eosinophil derived neurotoxin (EDN). It was also demonstrated that this preparation contained high levels of oxidised hCG. r-hCG was confirmed to be essentially intact hCG, free from contaminant proteins and with very low levels of oxidised hCG.

Comparative analytical characterization of two commercial human follicle-stimulating hormones extracted from human urine.

OBJECTIVE: Pharmaceutical preparations of human menopausal gonadotrophin (hMG), urine-derived follicle-stimulating hormone (u-FSH) and highly purified u-FSH (u-FSH-HP) have been available since the early 1960s and the mid 1980s and 1990s, respectively. Another commercial preparation of u-FSH-HP, Folyrmon P, was launched in Japan in 1999. The aim of this study is to assess the purity of Folyrmon P and to compare it with Fertinorm-P, another commercial preparation of u-FSH-HP that has been available since 1993. METHODS: Folyrmon P and Fertinorm-P were assessed for total protein content, biological activity, immunological activity, specific activity, purity and levels of protein contamination. RESULTS: Folyrmon P, which is extracted from the urine of post-menopausal women, has a specific activity of between 4000 and 5000 IU/mg, while Fertinorm-P, which is also manufactured from the urine of post-menopausal women, has a specific activity of at least 10,000 IU/mg. It has been well documented that commercially available hMG and u-FSH preparations can contain a number of urine-derived protein contaminants. This also proves to be the case for Folyrmon P, in which contaminant proteins other than FSH were shown to be present. It was also demonstrated that both preparations, Folyrmon P and Fertinorm-P, contained high levels of oxidized FSH. CONCLUSIONS: The low specific activity and high level of contaminants in Folyrmon P indicate that this u-FSH is not highly purified. Overall, Fertinorm-P, with higher specific activity and lower levels of contaminant proteins, appears to be of higher quality compared with Folyrmon P.