Determination of zinc incorporation in the Zn-substituted gallophosphate ZnULM-5 by multiple wavelength anomalous dispersion techniques.

The location of isomorphously substituted zinc over eight crystallographically different gallium sites has been determined in a single-crystal study of the gallophosphate ZnULM-5, Ga((16-x))Zn(x)(PO(4))(14)(HPO(4))(2)(OH)(2)F(7), [H(3)N{CH(2)}(6)NH(3)](4), 6H(2)O, in an 11 wavelength experiment, using data from Station 9.8, SRS Daresbury. The measurement of datasets around the K edges of both Ga and Zn, as well as two reference datasets away from each absorption edge, was utilized to selectively exploit dispersive differences of each metal atom type in turn, which allowed the major sites of Zn incorporation to be identified as the metal 1 and 3 sites, M1 and M3. The preferential substitution of Zn at these sites probably arises because they are located in double four-ring (D4R) building units which can relax to accommodate the incorporation of hetero atoms. As the crystal is non-centrosymmetric, with space group P2(1)2(1)2, it was also possible to use anomalous differences to corroborate the results obtained from the dispersive differences. These results were obtained firstly from difference Fourier maps, calculated using a phase set from the refined structure from data measured at the Zr K edge. Also, refined dispersive and anomalous occupancies, on an absolute scale, could be obtained using the program MLPHARE, allowing estimates for the Zn incorporation of approximately 22 and 18 at. % at the M1 and M3 sites to be obtained. In addition, f' and f'' values for Ga and Zn at each wavelength could be estimated both from MLPHARE results, and by refinement in JANA2006. The fully quantitative determinations of the dispersive and anomalous coefficients for Ga and Zn at each wavelength, as well as metal atom occupancies over the eight metal atom sites made use of the CCP4's MLPHARE program as well as SHELXL and JANA2006. The results by these methods agree closely, and JANA2006 allowed the ready determination of standard uncertainties on the occupancy parameters, which were for M1 and M3, 20.6 (3) and 17.2 (3) at %, respectively.

Extracorporeal treatment of salicylate or acetaminophen poisoning--is there a role?

Hemodialysis or sorbent hemoperfusion has been used in the management of clinical overdose of salicylates or acetaminophen. Hemodialysis offers considerable benefit in severe salicylate poisoning and is preferred to hemoperfusion or peritoneal dialysis, since it more rapidly corrects acid-base and electrolyte abnormalities than does hemoperfusion, and since it is clearly more efficient than is peritoneal dialysis for the removal of salicylates. Charcoal hemoperfusion in animal studies and hemodialysis in man have been shown to accelerate acetaminophen elimination from the body. Hemodialysis and hemoperfusion are of questionable benefit in clinical acetaminophen overdose. However, our clinical experience to date with charcoal hemoperfusion in "late" acetaminophen overdose has been associated with a less notable increase in liver enzyme concentrations in comparison with results of retrospective studies of series of patients treated or not treated with sulfhydryl donors.

Surface coordination chemistry: corrosion inhibition by tetranuclear cluster formation of iron with salicylaldoxime.

A tetranuclear iron cluster is the principal component of the purple coatings produced by treating a mild steel surface with a salicylaldoxime corrosion inhibitor. This was shown by comparison of the spectroscopic data with those of the cluster [{Fe(salH)(HsalH)}4 ], which was obtained from FeCl3 and salicylaldoxime (H2 salH) and has a distorted tetrahedral arrangement of Fe(III) atoms coordinated by terminal (1-) and bridging (2-) salicylaldoximate ligands (the central core of the cluster is depicted).

Partial reduction of annulated heterocycles as a general route to medium rings containing oxygen and nitrogen.

The preparation of annulated furans and pyrroles is described as part of a general strategy for the synthesis of medium ring heterocycles. After Birch reduction, the corresponding dihydro compounds were oxidatively cleaved to produce medium ring ethers and amines in an efficient manner. This methodology was successfully applied to the formation of eight- and nine-membered cyclic ethers and nine-membered cyclic amines. Attaching a chiral auxiliary (bismethoxymethylpyrrolidine) to the furan allowed the formation of nine-membered ethers in 95% ee.

The regioselective aminohydroxylation of allylic carbamates.

The synthesis and aminohydroxylation of a series of acyclic allylic carbamates is described: the formation of a putative O=Os=NR linkage between the transition metal and substrate is proposed to account for the high levels of regioselectivity that were observed; proof of the structure of one of the aminohydroxylation products was obtained through X-ray crystallography.

Atropisomeric amides as chiral ligands: using (-)-sparteine-directed enantioselective silylation to control the conformation of a stereogenic axis

An enantiomerically pure (1-trimethylsilyl)ethyl group, constructed by a (-)-sparteine-directed enantioselective quench of a laterally lithiated tertiary aromatic amide, exerts powerful thermodynamic control over the conformation of the adjacent tertiary amide substituent. Ortholithiation and functionalization of the amide in the 6-position allows the single amide conformer to be trapped as an enantiomerically and diastereoisomerically pure amide atropisomer. Protodesilylation of the amide gives functionalized atropisomeric amides with a stereogenic axis of single absolute configuration, whose barriers to racemization have been determined by polarimetry. Enantiomerically pure amides bearing phosphine substituents are effective ligands in a Pd-catalyzed allylic substitution reaction-the first use of a nonbiaryl atropisomer as a chiral ligand-and give products with 90% ee. The rate of racemization of the phosphine-substituted amide is powerfully influenced by the presence of palladium.

Investigations of Amavadin.

The development of the understanding of the co-ordination chemistry and the properties of Amavadin, the chemical form in which vanadium is accumulated by the Amanita genus of mushrooms, is reviewed.

Determination of the site of incorporation of cobalt in CoZnPO-CZP by multiple-wavelength anomalous-dispersion crystallography.

Data were collected from a crystal of CoZnPO-CZP {sodium cobalt-zinc phosphate hydrate, Na(6)[Co(0.2)Zn(0.8)PO(4)](6).6H(2)O} using synchrotron radiation at ELETTRA at the inflection point and 'white line' for both the cobalt and zinc K edges, and at 1.45 Å, a wavelength remote from the K edges of both metals. The data were processed using the programs DENZO and SCALEPACK. The CCP4 program suite was used for the scaling of data sets and the subsequent calculation of dispersive difference Fourier maps. Optimal scaling was achieved by using a subset of reflections with little or no contribution from the metal atoms (i.e. which were essentially wavelength independent in their intensities) and using weights based on the sigma's to obtain an overall scale factor in each case. Phases were calculated with SHELXL97 based on the refined structure using a much higher resolution and complete Cu Kalpha data set. An occupancy of 100% by zinc at the two metal-atom sites was assumed. The dispersive difference Fourier map calculated for zinc gave two peaks above the background of similar heights at the expected metal-atom sites. The peak height at the Zn1 site was a little higher than at the Zn2 site. The dispersive difference Fourier map calculated for cobalt gave just one peak above the background, at the Zn1 site, and only a small peak at the Zn2 site, thus indicating that incorporation of cobalt takes place mainly at one site. Refinement of the zinc occupancies using MLPHARE reinforces this conclusion. The chemical environment of each site is discussed.

Staphylococcus aureus infection complicating haemarthroses in elderly patients.

The case histories of 3 elderly patients who developed haemarthrosis of osteoarthritic joints with subsequent infection with staphylococcus aureus, are described. Trauma to the affected joints was a predisposing factor in 2 patients and, while only one patient developed clinical signs of sepsis, all had marked elevation of the erythrocyte sedimentation rate. Although suspicion of joint sepsis was obscured by the presence of a coexistent haemarthrosis, routine culture of joint aspirates showed infection with staphylococcus aureus and all patients recovered well with antibacterial therapy.

Delayed cutaneous hypersensitivity in rheumatoid arthritis: the influence of nutrition and drug therapy.

Significant depression of delayed cutaneous hypersensitivity (DCH) to seven common recall antigens was found in 50 patients with rheumatoid arthritis (RA) compared with 50 matched controls. Complete skin anergy was seen in 12 (24%) of the RA patients but in none of the control subjects. In addition, a nutritional assessment of all subjects tested showed significantly lower serum albumin and body mass indices in the RA compared with the control group. Analysis of these 100 subjects showed a significant correlation (r = 0.53, p less than 0.001) between the number of positive skin reactions and the concentration of serum albumin suggesting an association between nutritional status and DCH. No single factor could be identified to distinguish the reactive and anergic RA patients with the possible exception of drug treatment in that a higher proportion of patients on sodium aurothiomalate or immunosuppressive therapy than D-penicillamine was found in the anergic group. It is likely that the cause of impaired DCH in RA is multifactorial and our findings suggest that drug treatment and nutritional status may be an important contributor to it.

Theophylline absorption by effervescent activated charcoal (Medicoal).

Plasma theophylline concentrations were measured in six volunteers given 675 mg of a sustained-release preparation (Phyllocontin). Significant reductions in both the mean recorded peak theophylline plasma concentrations and the mean 12-hour theophylline bioavailability were observed after the administration of effervescent activated charcoal (Medicoal) in single and multiple doses. These results indicate the potential use of activated charcoal in the management of theophylline poisoning.

Bis

In the title compound, [Zn(C(8)H(10)N(3)O(2))(2)], the Zn atom displays a highly distorted octahedral coordination involving O and N atoms of two bidentate planar ligands approximately orthogonal to each other; the dihedral angle between the ligand planes is 84.95 (4) degrees. The ligand molecules show great asymmetry in their bonding to the Zn(2+) ion, with Zn-O bond distances ranging between 2.056 (2) and 2.534 (2) A. The planar phenyl ring and the trigonal-planar geometry about the triazene N atom bonded to the phenyl ring suggest a resonance interaction extending over adjacent atoms.

4-Methyl-N-

The title compound, C(20)H(19)NO(2)S(2), is formed by a palladium-copper-catalyzed reaction between 4-methyl-N-[2-(prop-2-ynylsulfanyl)phenyl]benzenesulfonamide and p-iodotoluene. The molecules contain three essentially planar parts, namely an aminothiophenol moiety (A), a toluenesulfone moiety excluding the oxo ligands (B) and a tolyl group (C), approximately orthogonal to each other; the dihedral angles A/B, A/C and B/C are 111.6 (1), 89.3 (1) and 101.4 (1) degrees, respectively. Intermolecular N-H.O hydrogen bonds link the molecules into infinite one-dimensional chains.

Liquid preparations for oral administration.

Liquids are easier to swallow and act more quickly than solid dosage forms, but may be unpalatable and relatively unstable. Solutions contain dissolved drugs and may be difficult to formulate or to make palatable; suspensions are usually more pleasant to take but accuracy of dosing may be affected by settling of drug particles. The dose of a drug in liquid and solid form may differ because different drug compounds are often used. Liquids contain many additives which can give rise to adverse affects in the patient.

Solid oral dosage forms.

The oral route of drug administration is the most convenient for patients, with tablets emerging as the most popular solid oral dosage form used today. Standard compressed, controlled-release and coated tablets are the most common form of solid oral dosages. A wide range and diversity of ingredients are often included in tablet formulations. A knowledge of the difference between tablet and capsule formulations should enable nurses to improve patient compliance with respect to solid oral dosage forms.

Science experiments via telepresence at a synchrotron radiation source facility.

Station 9.8 is one of the most oversubscribed and high-throughput stations at the Synchrotron Radiation Source, Daresbury, whereby awarded experimental time is limited, data collections last normally no longer than an hour, user changeover is normally every 24 h, and familiarity with the station systems can be low. Therefore time lost owing to technical failures on the station has a dramatic impact on productivity. To provide 24 h support, the application of a turnkey communication system has been implemented, and is described along with additional applications including its use for inter-continental classroom instruction, user training and remote participation.

The use of softer X-rays in the structure elucidation of microporous materials.

Microporous materials, such as zeolites and aluminophosphates, have many applications as molecular sieves and shape-selective catalysts. This is due to their three-dimensional frameworks, which contain regular pores and channels, to their high acidity, arising from Brønsted and Lewis acid active sites, and to the incorporation of transition metal atoms into framework sites. This review firstly provides an introduction into the nature and properties of these materials, and their important applications; the difficulties in their full characterization and possible methods of elucidating their structures are then outlined; finally, methods of characterization, utilizing 'softer X-rays' are introduced. The first method is the determination of low concentrations of transition metals, incorporated into the frameworks using single crystal anomalous dispersion crystallography; synchrotron radiation is used to tune to the absorption edge of the metal atom in question, in order to change its signal relative to that of the rest of the structure, thereby allowing the pinpointing of its positions and the determination of its concentration at each site in the framework. Secondly, the use of longer wavelengths in powder diffraction studies is described, which, by stretching out the powder pattern, thereby reduces the overlapping of the diffraction peaks, thus allowing the structure to be solved by conventional direct methods. Finally, the use of X-ray absorption spectroscopy to determine the metal incorporation and the nature of coordination at the metal atom sites, in Mn silicalite-1 and FAPO-36, are described.

[Rheumatic symptoms in primary hyperparathyroidism].

In a retrospective survey of 34 patients with primary hyperparathyroidism (HPT), 18 (53%0 complained of musculo-skeletal symptoms during the 12 months before the diagnosis was made and 9 (26%) attended at some time for either a rheumatological or orthopaedic consultation. Myalgia was the most frequently reported symptom which occurred in 41% of patients. Arthralgia, mainly affecting the large joints was present in 11 (32%) patients, 2 of whom had an erosive synovitis mimicking rheumatoid arthritis. Radiological abnormalities were seen in 8 patients. Clinicians should be aware of the variety and frequency of musculo-skeletal symptoms associated with HPT and should consider including serum calcium measurements when investigating rheumatic complaints.