A Scandium‐Stabilized Diisophosphaethynolate Ligand: [OCPPCO]4−

The first example of the OCPPCO ligand, diisophosphaethynolate, is reported via reductive coupling of a Sc?OCP precursor. Upon reduction with KC₈, isolation of the dinuclear complex, namely [K(OEt₂)]₂[(nacnac)Sc(OAr)]₂(OCPPCO), is observed, leading to a unique motif [OCPPCO]^4?, stabilized by two scandium centers. Detailed NMR spectra of all complexes as well as IR and single crystal X‐ray studies were obtained to fully elucidate the nature of these complexes in solution as well as in the solid state. Theory is combined to probe the electronic structure and orbitals responsible for the bonding interactions in the Sc?OCPPCO?Sc skeleton but also to compare to the linear mode observed in the precursor.     

Scaled Enflo type is equivalent to Rademacher type

We introduce the notion of the scaled Enflo type of a metricspace, and show that for Banach spaces, scaled Enflo type pis equivalent to Rademacher type p.     

Bernoulli thinning of a Markov renewal process

A Bernoulli thinning of a Markov renewal process is investigated. The properties of the thinned process are considered and are related to the properties of the original process. The parameters, moments and equilibrium of the thinned process are determined in terms of the parameters defining the underlying Markov renewal process. Results are illustrated by examples. © 1998 John Wiley & Sons, Ltd.     

Environment Polarity in Proteins Mapped Noninvasively by FTIR Spectroscopy

The polarity pattern of a macromolecule is of utmost importance to its structure and function. For example, one of the main driving forces for protein folding is the burial of hydrophobic residues. Yet polarity remains a difficult property to measure experimentally, due in part to its non-uniformity in the protein interior. Herein, we show that FTIR linewidth analysis of noninvasive 1-(13)C=(18)O labels can be used to obtain a reliable measure of the local polarity, even in a highly multi-phasic system, such as a membrane protein. We show that in the Influenza M2 H(+) channel, residues that line the pore are located in an environment that is as polar as fully solvated residues, while residues that face the lipid acyl chains are located in an apolar environment. Taken together, FTIR linewidth analysis is a powerful, yet chemically non-perturbing approach to examine one of the most important properties in proteins - polarity.     

Limitations to Fréchet’s metric embedding method

Fréchet’s classical isometric embedding argument has evolved to become a major tool in the study of metric spaces. An important example of a Fréchet embedding is Bourgain's embedding [4]. The authors have recently shown [2] that for every ε>0, anyn-point metric space contains a subset of size at leastn ^1−ε which embeds into ℓ₂ with distortion . The embedding used in [2] is non-Fréchet, and the purpose of this note is to show that this is not coincidental. Specifically, for every ε>0, we construct arbitrarily largen-point metric spaces, such that the distortion of any Fréchet embedding into ℓ_p on subsets of size at leastn ^1/2+ε is Ω((logn)^1/p ). Supported in part by a grant from the Israeli National Science Foundation. Supported in part by a grant from the Israeli National Science Foundation. Supported in part by the Landau Center.     

Automatic field machine technology

Current crop production schemes fail to offer the economic potential for reduced costs, increased yields and improved product quality, that could be derived from controlled traffic farming techniques utilizing multipurpose overhead mechanical frames. The development of new field machine technology will integrate total production under a single linear-travel system. This new technology is vital to reduce soil compaction with significantly decreased crop yield under irrigated, intensive-production conditions. This new machine technology will allow advanced chemical spray application techniques with enclosed shrouds for minimum drift. Precision planting, cultivating, plastic laying, irrigating, chemigating, harvesting (manual or mechanized) and materials handling will be accomplished by this technology. Onboard packing of more mature and thus more flavored vegetables with maximum nutrients will increase quality, reduce post-harvest losses, expand consumer acceptance and improve grower profit. Such a system could eventually serve as an automatic carrier for robot devices that would selectively harvest crops. The possibility of using electric power for this system offers higher economical potential, especially when using off-peak electricity. A versatile carriage drive with integral tool bar and hitch to mount implements, harvest elements and perform all operational functions for crop production, is an essential part of the system. Conveyors running along the mainframe will convey the yields gently out of the field. eliminating the large and heavy containers used on existing harvesting machines.     

Microwave spectrum,torsional excitation energy,partial structure,and dipole moment of oxiranecarboxaldehyde

The microwave spectrum of oxiranecarboxaldehyde (glycidaldehyde) has been studied in the 8–40 GHz region. Transitions in the ground and first seven excited states of the torsional motion of the aldehyde group have been assigned for the species with the oxygen atom of the aldehyde group trans to the oxirane ring. The v = 0 to v = 1 torsional excitation energy is estimated to be 140 ± 10 cm^?1. The population of any other torsional conformer is less than 5% of the trans species at 200 K. Structural parameters were derived from rotational constants of the three singly substituted ¹³C species, whose spectra were observed in natural abundance. Substitution parameters are $\text{r}{}_{\mathrm{<mtext>CC</mtext>}}\text{(ring) = 1.453 ±0.025}\text{A}\text{?}$, $\text{r}{}_{\mathrm{<mtext>CC</mtext>}}\text{(ald.) = 1.469 ± 0.010}\text{A}\text{?}$, ∠CCC = 119.8 ± 2.0°. The dipole moments determined by means of the Stark effect are μ_a = 1.932 ± 0.005 D, μ_b = 1.511 ± 0.017 D, and μ_c = 0.277 ± 0.156 D, with μ_t = 2.469 ± 0.031 D.     

Tailor-made agarose-based reactive beads for hemoperfusion and plasma perfusion

Composite beads of approximately 1mm diameter, made of cross-linked agarose and containing Fuller’s Earth or zirconium oxide powders, were prepared and used in extracorporeal systems for blood detoxification. The former was used for the removal of Paraquat, while the latter was used to remove inorganic phosphate from hyper-phosphatamic animals with or without acute renal failure. The high surface area of the powder, combined with the low resistance to diffusion in the cross-linked agarose matrix, are highly advantageous. The crosslinking provides high mechanical strength, heat stability, prolonged shelf life, good blood flow characteristics, and prevents the release of fine particles into the blood. Crosslinked agarose beads of 1 mm diameter, containing chemically-bound heparin were also prepared, and used as a model for direct contact removal of LDL-cholesterol from the blood of familial hypercholesterolemic patients by hemoperfusion. The high capacity of these beads (over 5 mg LDL/mL beads) indicates that this clinical modality can replace the highly expensive plasmapheresis procedure presently used.