Efficient Synthesis of Highly Active Phospha‐Isosteres of the Influenza Neuraminidase Inhibitor Oseltamivir

With a Hunsdiecker–Barton iododecarboxylation strategy, we converted the carboxylate group of the oseltamivir precursor into exemplary phosphonate monoesters. In all cases, K_i values towards influenza virus sialidase remained in the sub‐nanomolar range. We have thus made valuable structural space available for the design of novel oseltamivir‐based tools for influenza virus research.

     

Development and characterization of PEEK/carbon nanotube composites

New poly(ether ether ketone) (PEEK) based composites have been fabricated by the incorporation of single-walled carbon nanotubes (SWCNTs) using melt processing. Their structure, morphology, thermal and mechanical properties have been investigated. Scanning electron microscopy observations demonstrated a more uniform distribution of the CNTs for samples prepared following a processing route based on polymer ball milling and CNT dispersion in ethanol media. Thermogravimetric analysis indicated a remarkable improvement in the thermal stability of the matrix by the incorporation of SWCNTs. Differential scanning calorimetry showed a decrease in the crystallization temperature with increasing SWCNT content, whilst no significant changes were observed in the melting of the composites. The crystallite size determined by X-ray diffraction decreased at high SWCNT loading, which is attributed to the spatial limitations on crystal growth by confinement within the CNT network. Dynamic mechanical analysis revealed an increase in the storage moduli, hence in the rigidity of the systems, with increasing SWCNT content. Their addition shifts the glass transition peak to higher temperatures due to the restriction in chain mobility imposed by the CNTs. Higher thermal stability and mechanical strength were found for composites with improved dispersion of the SWCNTs.     

Improving the transfer of near infrared prediction models by orthogonal methods

Eight calibration transfer methods based on the removal of orthogonal signal were compared for the standardization of whole soybean protein and oil models. Dynamic orthogonal projection (DOP), transfer by orthogonal projection (TOP), error removal by orthogonal subtraction (EROS), orthogonal signal correction (OSC), and orthogonal projections to latent structures (O-PLS) as well as the modification and extension of some of these methods were compared in the transfer of models in intra and inter-brand situations using two Foss Infratecs and two Bruins OmegAnalyzerGs. For each brand, a master was designated and its models transferred onto the second unit of its network and the two units of the second brand. Calibration models were transferable from brand to brand with similar or better precision than when each instrument was calibrated on its own calibration set (for Infratec 1229, the relative predictive determinant (RPD) increased in intra and inter-brand calibration transfer situations from 10.42 to 11.45 and 10.57, with DOP and EROS respectively). Performance of each method was different across parameters, instruments, and validation sets. DOP modifications on the determination of the difference matrix showed promising results while TOP and EROS extensions to include variability specifically present in certain crop years did not bring any beneficial effects.     

Real options and technology management: Assessing technology migration options in wireless industry

The wireless industry is currently undergoing a major transition from second generation (2G) to third generation (3G) wireless technologies. The paper attempts to assess wireless technology migration options using the real options approach (ROA) to support the wireless network operators’ strategic decisions: to migrate or not, if so, which migration path to take. The preliminary result shows that the evolution of wireless network technologies between generations is desirable, but not within generations. Finally, from a strategic perspective, we should consider the possible challenges that may hinder migration. By identifying these challenges, we can be more watchful of transition pitfalls and can choose a better alternative.     

Reactive and non-reactive transport modelling in partially water saturated argillaceous porous media around the ventilation experiment, Mont Terri

At Mont Terri Underground Research Laboratory (URL) Switzerland, a specific experiment has been performed in a tunnel, in order to investigate the hydro-mechano-chemical (HMC) perturbations induced in the argillaceous formation by forced ventilation. This experiment has been selected in the international project DECOVALEX to be used for process model development and validation. The numerical simulation of the geochemical response to the ventilation experiment (VE) is the object of the present paper, focusing on the transport of chloride as a conservative species and sulphate as a reactive species. Utilising the validated hydro-mechanical (HM) results from earlier steps of the DECOVALEX task, reactive and non-reactive transport models, incorporating the current understanding of the geochemistry at the site, were successfully constructed for the whole experimental period. The associated parametric and process uncertainty analyses clearly demonstrate that the basic HM understanding must be sound. However, to demonstrate this degree of robustness, the explicit inclusion of process representations of water desaturation, liquid vaporisation, species exclusion porosity, and redox processes, is required.     

Evidence of perchlorate (ClO4-) reduction in plant tissues (poplar tree) using radio-labeled 36ClO4-

Phytoremediation of perchlorate (ClO4) by poplar trees Populus deltoidex nigrawas investigated using small cuttings growing in hydroponic Hoagland solution and plant tissue cultures, consisting of spherical photosynthetic cell aggregates (i.e. nodules) developing in Murashige and Skoog culture medium. Both plants and nodules were grown under a 16 h/8 h photoperiod cycle and under sterile conditions. Degradation experiments, performed by the incubation of pregrown plants and nodules in the presence of 36Cl radio-labeled ClO4- (25 mg L(-1)), showed a reduction of the initial ClO4- concentration in the solution of about 50% after 30 d of incubation. Analysis of the distribution of radioactivity in different plant fractions indicated that 27.4% of the total was translocated to the leaves, while 66.9% remained in the solution. Very little radioactivity (less than 3.0%) was detected in the other parts of the plants. 32.0% of the radioactivity recovered in the solution was shown to consist of 36Cl- and 68.0% of nontransformed 36ClO4-. The radioactivity recovered in the leaf extracts was distributed as chloride (36Cl-) (1.6% of the total), chlorite (36ClO2-) (2.4%), chlorate (36ClO3-) (4.8%), nontransformed 36ClO4- (21.6%), and an unidentified organic compound (1.4%). The radioactivity recovered in the solution containing submerged nodules consisted of 36Cl- (6.4% of the total), 36ClO3- (1.3%), and nontransformed 36ClO4- (51.5%). Radioactivity detected in the nodule extracts was distributed as 36Cl- (2.0% of the total), 36ClO2- (5.2%), 36ClO3- (6.4%), 36ClO4- (22.7%), and an unidentified organic compound (0.5%). These results provide evidence of perchlorate reduction inside poplar tree tissues. 36ClO4- is partially reduced to 36ClO3-, 36ClO2-, and 36Cl-.     

Microgravity materials and life sciences research applications of digital holography

We investigate the utility of digital holographic interferometry for analyzing gravity-dependent mass transport phenomena as applicable to materials and life science research topics. Digital holography is useful for measurement of parameters that introduce phase changes in light traversing the material of interest, such as temperature or concentration variations in an aqueous environment. We have constructed, tested, and verified a compact, portable digital holographic monitor (DHM) suitable for characterization of transparent samples. It has proved useful for the study of systems such as protein crystal growth solutions and has been proposed for further application into studies involving microbial metabolism. The DHM is also sufficiently rugged for field operation in challenging environments a s may be encountered in a spacecraft or industrial setting. We discuss some system capabilities and limitations.     

Heparin-like polymers derived from dextran enhance colonic anastomosis resistance to leakage

OBJECTIVE: To determine whether a short computer interview could be used in place of a full diagnostic interview to obtain psychiatric diagnoses, the authors examined the short interview's sensitivity, specificity, and diagnostic agreement with the full interview. METHODS: Patients recently discharged from a university psychiatric service were interviewed in two back-to-back sessions, one in which a full diagnostic interview was used and the other in which a short computer interview was used. Based on diagnoses derived from both interviews, the sensitivity and specificity of the short interview and kappa values reflecting the diagnostic agreement of the two interviews were calculated. RESULTS: The short interview had high sensitivity and specificity and excellent diagnostic agreement with the full interview for most disorders. It also had a significantly shorter administration time. However, it missed a substantial percentage of cases of generalized anxiety disorder and misclassified as in remission a substantial proportion of patients with active cases of post-traumatic stress disorder. CONCLUSIONS: With few exceptions, the short interview may be substituted for the full interview when missing an active case is not important or when a count of individual symptoms and subtyping of disorders are not needed. Such uses include screening subjects for inclusion in a study and obtaining an overview of a patient's lifetime psychiatric status.     

Species-dependent enantioselective glucuronidation of carprofen

1. The stereoselective glucuronidation of carprofen, a non-steroidal anti-inflammatory drug, was investigated in vitro using microsomes prepared from liver of different species (rat, dog, horse, sheep and man) or UGT2B1 expressed in fibroblasts. 2. The Km towards the drug was very similar among these species and for the two enantiomers, whereas the Vmax varied substantially according to the animal used. The rat exhibited a high stereoselective glucuronidation whereas other species, including man, presented a low stereoselectivity. The R-enantiomer was glucuronidated at a more efficient rate than its enantiomorph, and was a better substrate (in terms of Vmax/Km). 3. To explain the enantioselective disposition of carprofen in man and in the different species, the ratio of the enzymatic efficacies (Vmax/Km) were compared with the ratio of the pharmacokinetic parameters AUCs. The basic hypothesis that the intrinsic clearance reflect the enantioselective behaviour of carprofen seemed substantiated when we focused on man and rat glucuronidation, but the in vivo-in-vitro correlation was not possible in other species. 4. In conclusion, the chiral pharmacokinetics of carprofen is less dependent on the stereoselective glucuronidation than other stereoselective processes such as protein binding of carprofen, enzymatic hydrolysis, or renal elimination of glucuronides.     

High-temperature coupling of high-speed GPC with continuous viscometry. II. Ethylene–vinyl acetate copolymers

An application of the high temperature coupling of a gel permeation chromatograph with a home-made continuous viscometric detector is described. It concerns the comprehensive characterization of ethylene–vinyl acetate copolymers. Suitable chromatographic conditions are chosen to enable a correct use of the universal calibration concept. Through analysis of poly(vinyl acetate) fractions and commercial polyethylene samples, a comparison is made with the results of classical measurements. Average molecular weights as well as intrinsic viscosity appear to be in good agreement within experimental error, which proves the system for the characterization of random ethylene–vinyl acetate copolymers. In attempting to obtain a reliable estimate of long chain branching frequency λ, a series of commercial samples has been selected, with the vinyl acetate weight fraction within the range 0–45%. As a rule, experimental viscosity law exhibits two parts, a straight line with a Mark–Houwink exponent 0.7 in the low molecular weight region and a curvature, well smoothed by a third-degree polynomial regression. Consequently, long chain branching does not appear before a limiting molecular weight of about 50,000. Beyond this limit, λ is 0.5 × 10^?4, with no dependence on molecular weight, which resembles low density polyethylene.