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After crystallization during ionothermal syntheses in phospho­nium-containing ionic liquids, the structure of (NH4)3Al2(PO4)3 [tri­ammonium dialuminum tris­(phosphate)] was refined on the basis of powder X-ray diffraction data from a synchrotron source. (NH4)3Al2(PO4)3 is a member of the structural family with formula A3Al2(PO4)3, where A is a group 1 element, and of which the NH4, K, and Rb forms were previously known. The NH4 form is isostructural with the K form, and was previously solved from single-crystal X-ray data when the material (SIZ-2) crystallized from a choline-containing eutectic mixture [Cooper et al. (2004). Nature, 430, 1012–1017]. Our independent refinement incorporates NH4 groups and shows that these NH4 groups are hydrogen bonded to framework O atoms present in rings containing 12 T sites in a channel along the c-axis direction. We describe structural details of (NH4)3Al2(PO4)3 and discuss differences with respect to isostructural forms. [ABSTRACT FROM AUTHOR]

Zeolites are porous aluminosilicate materials utilized in a variety of sorption, separation, and catalytic applications. The oil refining industry in particular has seen a number of significant advances due to the introduction of new technologies enabled by new zeolites. Of particular importance are zeolites with 10‐ or 12‐membered ring pores, resulting in pore shapes and sizes appropriate for the interaction with small hydrocarbon molecules. Here, the synthesis of a new zeolite UZM‐55 is reported and the idealized structure thereof is presented. The most complex structure solved to date, UZM‐55 possesses a large triclinic unit cell containing 52 T‐sites. The material uniquely contains both 10‐ and 12‐membered ring pores in a single, undulating one‐dimensional channel, the first example in a zeolitic material of multiple delimiting rings in a single channel. This discovery opens new opportunities in shape‐selective adsorption and catalysis. Demonstrated here is the unique adsorption behavior of UZM‐55, shown both experimentally and computationally to adsorb one nonane molecule per unit cell in a linear conformation. A complex tale: The synthesis and structure solution of UZM‐55, the most structurally complex zeolite thus known, is reported. UZM‐55 is the first zeolite structure solved in P1, contains 52 independent T‐sites and a unique, undulating pore channel with both 10‐ and 12‐membered delimiting rings present in the same pore. Computational results show that nonane is adsorbed in a linear conformation with no kink defects within the pore, confirming the n‐nonane experimental results. [ABSTRACT FROM AUTHOR]

Adsorption of CO2andCH4has been measuredon the Na-, K-, and Cs-forms of zeolite Rho (0–9 bar; 283–333K). Although CH4is excluded, CO2is readilytaken up, although the uptake at low pressures decreases strongly,in the order Na+> K+> Cs+. Structuralstudies by powder X-ray diffraction (PXRD) suggest that cations inintercage window sites block CH4adsorption; however, inthe presence of CO2, the cations can move enough to permitadsorption (several angstroms). Determination of time-averaged cationpositions during CO2adsorption at 298 K by Rietveld refinementagainst PXRD data shows that (i) in Na-Rho, there is a small relaxationof Na+cations within single eight-ring (S8R) sites, (ii)in Cs-Rho, D8R cations move to S8R sites (remaining within windows)and two phases of Cs-Rho (I4̅3m, Im3̅m) are present overa wide pressure range, and (iii) in K-Rho, there is relocation ofsome K+cations from window sites to cage sites and twophases coexist, each with I4̅3msymmetry, over the pressure range of 0–1 bar. The final cationdistributions at high PCO2aresimilar for Na-, K-, and Cs-Rho, and adsorption in each case is onlypossible by “trapdoor”-type cation gating. Complementarystudies on K-chabazite (Si/Al = 3) also show changes in time-averagedcation location during CO2adsorption. [ABSTRACT FROM AUTHOR]

Ab initio molecular dynamics (AIMD) simulations have been used to predict structural transitions of the breathing metal–organic framework (MOF) MIL-53(Sc) in response to changes in temperature over the range 100–623 K and adsorption of CO2 at 0–0.9 bar at 196 K. The method has for the first time been shown to predict successfully both temperature-dependent structural changes and the structural response to variable sorbate uptake of a flexible MOF. AIMD employing dispersion-corrected density functional theory accurately simulated the experimentally observed closure of MIL-53(Sc) upon solvent removal and the transition of the empty MOF from the closed-pore phase to the very-narrow-pore phase (symmetry change from P21/c to C2/c) with increasing temperature, indicating that it can directly take into account entropic as well as enthalpic effects. We also used AIMD simulations to mimic the CO2 adsorption of MIL-53(Sc) in silico by allowing the MIL-53(Sc) framework to evolve freely in response to CO2 loadings corresponding to the two steps in the experimental adsorption isotherm. The resulting structures enabled the structure determination of the two CO2-containing intermediate and large-pore phases observed by experimental synchrotron X-ray diffraction studies with increasing CO2 pressure; this would not have been possible for the intermediate structure via conventional methods because of diffraction peak broadening. Furthermore, the strong and anisotropic peak broadening observed for the intermediate structure could be explained in terms of fluctuations of the framework predicted by the AIMD simulations. Fundamental insights from the molecular-level interactions further revealed the origin of the breathing of MIL-53(Sc) upon temperature variation and CO2 adsorption. These simulations illustrate the power of the AIMD method for the prediction and understanding of the behavior of flexible microporous solids. [ABSTRACT FROM AUTHOR]

The crystal structure of the small pore scandium terephthalate Sc2(O2CC6H4CO2)3 (hereafter Sc2BDC3, BDC = 1,4-benzenedicarboxylate) has been investigated as a function of temperature and of functionalization, and its performance as an adsorbent for CO2 has been examined. The structure of Sc2BDC3 has been followed in vacuo over the temperature range 140 to 523 K by high resolution synchrotron X-ray powder diffraction, revealing a phase change at 225 K from monoclinic C2/c (low temperature) to Fddd (high temperature). The orthorhombic form shows negative thermal expansivity of 2.4 × 10-5 K-1: Rietveld analysis shows that this results largely from a decrease in the c axis, which is caused by carboxylate group rotation. 2H wide-line and MAS NMR of deuterated Sc2BDC3 indicates reorientation of phenyl groups via π flips at temperatures above 298 K. The same framework solid has also been prepared using monofunctionalized terephthalate linkers containing -NH2 and -NO2 groups. The structure of Sc2(NH2-BDC)3 has been determined by Rietveld analysis of synchrotron powder diffraction at 100 and 298 K and found to be orthorhombic at both temperatures, whereas the structure of Sc2(NO2-BDC)3 has been determined by single crystal diffraction at 298 K and Rietveld analysis of synchrotron powder diffraction at 100, 298, 373, and 473 K and is found to be monoclinic at all temperatures. Partial ordering of functional groups is observed in each structure. CO2 adsorption at 196 and 273 K indicates that whereas Sc2BDC3 has the largest capacity, Sc2(NH2-BDC)3 shows the highest uptake at low partial pressure because of strong -NH2⋯CO2 interactions. Remarkably, Sc2(NO2-BDC)3 adsorbs 2.6 mmol CO2 g-1 at 196 K (P/P0 = 0.5), suggesting that the -NO2 groups are able to rotate to allow CO2 molecules to diffuse along the narrow channels. [ABSTRACT FROM AUTHOR]

Crystalline microporous cobalt and nickel bisphosphonates with a hexagonal array of one-dimensional channels 1.8 nm in diameter have been prepared hydrothermally and provide the first example of the use of isoreticular chemistry in the synthesis of phosphonate metal-organic frameworks. The materials contain both physisorbed and coordinating water molecules in the as prepared form, but these can be removed to give permanent extra-large microporosity, with pore volumes of up to 0.68 cm3 g-1, and coordinatively unsaturated sites, with concentrations up to 4.25 mmol g-1. [ABSTRACT FROM AUTHOR]

An isolate of tomato bushy stunt virus was obtained from a tulip plant affected by a necrotic disease. The isolate differs from the type strain in virulence in some experimental hosts, and serologically is more closely related to a pelargonium leaf curl strain than to the type strain. When transmitted manually to tulip plants, both the tulip isolate and the type strain of tomato bushy stunt virus produced leaf symptoms indistinguishable from those caused by tobacco necrosis virus, but the tomato bushy stunt isolates had effects on the flowers different from those caused by tobacco necrosis virus. [ABSTRACT FROM AUTHOR]

A novel method for CO2 delivery to a porous material is reported, wherein a perfluorocarbon containing dissolved CO2 has been used as a pressure-transmitting liquid in a high-pressure single-crystal X-ray diffraction experiment. Pressure causes the gas to be squeezed out of the liquid into the host crystal, monitored via a single-crystal to single-crystal phase transition on uptake of CO2. [ABSTRACT FROM AUTHOR]

A series of univalent cation forms of zeolite Rho (M9.8Al9.8Si38.2O96, M = H, Li, Na, K, NH4, Cs) and ultrastabilized zeolite Rho (US-Rho) have been prepared. Their CO2 adsorption behavior has been measured at 298 K and up to 1 bar and related to the structures of the dehydrated forms determined by Rietveld refinement and, for H-Rho and US-Rho, by solid state NMR. Additionally, CO2 adsorption properties of the H-form of the silicoalumino-phosphate with the RHO topology and univalent cation forms of the zeolite ZK-5 were measured for comparison. The highest uptakes at 0.1 bar, 298 K for both Rho and ZK-5 were obtained on the Li-forms (Li-Rho, 3.4 mmol g-1; Li-ZK-5, 4.7 mmol g-1). H- and US-Rho had relatively low uptakes under these conditions: extra-framework Al species do not interact strongly with CO2. Forms of zeolite Rho in which cations occupy window sites between α-cages show hysteresis in their CO2 isotherms, the magnitude of which (Na+,NH4+ < K+ < Cs+) correlates with the tendency for cations to occupy double eight-membered ring sites rather than single eight-membered ring sites. Hysteresis is not observed for zeolites where cations do not occupy the intercage windows. In situ synchrotron X-ray diffraction of the CO2 adsorption on Na-Rho at 298 K identifies the adsorption sites. The framework structure of Na-Rho "breathes" as CO2 is adsorbed and desorbed and its desorption kinetics from Na-Rho at 308 K have been quantified by the Zero Length Column chromatographic technique. Na-Rho shows much higher CO2/C2H6 selectivity than Na-ZK-5, as determined by single component adsorption, indicating that whereas CO2 can diffuse readily through windows containing Na+ cations, ethane cannot. [ABSTRACT FROM AUTHOR]

Defective opsonization of heat-killed baker's yeast was found in all 14 children with fulminant hepatic failure (FHF) but returned to normal in two who recovered and was normal in six mothers of patients. Yeast opsonization was significantly correlated with factor B activity of FHF serum but not with other components of classical or alternative pathways of complement. Reconstitution and family studies suggested that defective yeast opsonization in FHF is secondary and, although dependent on factor B activity, is qualitatively and quantitatively similar to that of primary yeast opsonization deficiency. These findings suggest that the factors responsible for opsonization of yeasts, or their regulation, are synthesized or controlled by the liver. [ABSTRACT FROM AUTHOR]

Focuses on the surgical treatment for extrahepatic biliary atresia among infants in Great Britain. Identification of jaundice in infants; Symptoms of jaundice; Employment of Kasai's radical surgical approach.

An extended series of MIL-53(M)_X metal-organic frameworks (MIL = Materials of Institute Lavoisier; M = Al, Cr, Fe, Sc; X = Cl, CH3, NO2) have been systematically investiaged to explore the impact of the nature of both the metal centre and the functions grafted on to the organic linker on the mechanical behaviour of this family of highly flexible hybrid porous frameworks under the application of an external pressure of up to 3 GPa. The high-pressure X-ray diffraction measurements allowed the characterization of the pressure-induced phase transitions of the hydrated structures, the associated volume changes/pressure transitions, and their mechanical resilience through the determination of their bulk moduli. [ABSTRACT FROM AUTHOR]

Previous high-pressure experiments have shown that pressure-transmitting fluids composed of small molecules can be forced inside the pores of metal organic framework materials, where they can cause phase transitions and amorphization and can even induce porosity in conventionally nonporous materials. Here we report a combined high-pressure diffraction and computational study of the structural response to methanol uptake at high pressure on a scandium terephthalate MOF (Sc2BDC3, BDC = 1,4-benzenedicarboxylate) and its nitro-functionalized derivative (Sc2(NO2-BDC)3) and compare it to direct compression behavior in a nonpenetrative hydrostatic fluid, Fluorinert-77. In Fluorinert-77, Sc2BDC3 displays amorphization above 0.1 GPa, reversible upon pressure release, whereas Sc2(NO2-BDC)3 undergoes a phase transition (C2/c to Fddl) to a denser but topologically identical polymorph. In the presence of methanol, the reversible amorphization of Sc2BDC3 and the displacive phase transition of the nitro-form are completely inhibited (at least up to 3 GPa). Upon uptake of methanol on Sc2BDC3, the methanol molecules are found by diffraction to occupy two sites, with preferential relative filling of one site compared to the other: grand canonical Monte Carlo simulations support these experimental observations, and molecular dynamics simulations reveal the likely orientations of the methanol molecules, which are controlled at least in part by H-bonding interactions between guests. As well as revealing the atomistic origin of the stabilization of these MOFs against nonpenetrative hydrostatic fluids at high pressure, this study demonstrates a novel high-pressure approach to study adsorption within a porous framework as a function of increasing guest content, and so to determine the most energetically favorable adsorption sites. [ABSTRACT FROM AUTHOR]

Unlabelled: Psychological adjustment in children with liver disease was investigated. Three groups of children 6-15 years old participated: ten had undergone a liver transplant (Gp1), 15 had ongoing chronic liver disease (Gp2) and 15 were healthy controls (Gp3). Children who had had a transplant appeared well adjusted and thought of themselves as healthy rather than ill, although areas of vulnerability were present, for example increased anxiety. No differences emerged in terms of coping with common or illness-related problems or understanding of the causes of illness and use of medication. Gps 1 and 2 showed higher levels of understanding of the functions of the liver but less understanding of illness prevention when compared to their healthy peers. Gp2 experienced less control over their health when compared to the other two groups. Gp1 rated themselves as more "healthy" than Gp2 but less so than Gp3.Conclusion: Children with chronic liver disease are able to communicate how they deal with the stresses of the condition. Though well adjusted in many ways, those who have had a transplant still show areas of psychological vulnerability which need to be addressed in clinical practice. [ABSTRACT FROM AUTHOR]

Comments on various topics related to medicine in Great Britain. Aspects of rubella vaccination; Details on drug compliance in hypertensive patients; Lists of radiological techniques for controlling gastrointestinal bleeding.

To investigate the function of activated T lymphocytes in autoimmune chronic active hepatitis, 7 of 15 T-cell clones from the peripheral blood of 8 patients were studied. These clones showed specificity for liver-membrane antigen with proliferation when stimulated by rabbit liver cell membranes. 6 of these clones reacted with liver-specific lipoprotein complex, and 1 clone (and 3 subclones) responded to the asialoglycoprotein receptor (ASGPR), both known targets of immune attack in autoimmune chronic active hepatitis. 2 of these clones stimulated autologous B lymphocytes to produce liver-membrane-specific autoantibodies and antibody to the ASGPR. These results suggest that liver-membrane-specific activated T lymphocytes in peripheral blood may be important in the autoimmune attack of chronic active hepatitis. [ABSTRACT FROM AUTHOR]

Presents several letters to the editor published in the 'British Medical Journal' as of August 1989. Inquiries related to selection of surgeon as leader for the trauma team; Interrelations between the death at Lake Nyos and carbon dioxide emission; Scrutiny on the ethical practices involved in clinical research.

Anti-lymphocytic antibodies (ALA) have been described in a variety of autoimmune disorders. We have investigated the presence of ALA in autoimmune chronic active hepatitis (aCAH) starting in childhood. Using a modified Terasaki technique ALA were found in 17 of 18 patients with aCAH but in only one of 15 patients with alpha-1-anti-trypsin deficiency or Wilson's disease and three of 27 aged-matched healthy controls (P < 0.0005 for both). Sera from 12 patients with uncontrolled aCAH had significantly higher cytotoxicity values than sera from six children with inactive disease (P < 0.01). ALA were directed to T but not B lymphocytes and were not reactive with specific HLA antigens. No preferential killing was observed against CD4 or CD8 positive T lymphocytes. Characterization of ALA revealed them to be cold-reactive IgM. The possible role of ALA in aCAH is discussed. [ABSTRACT FROM AUTHOR]

An indirect immunofluorescence technique was used to investigate the immunoglobulin class, IgG subclass, light chain type and complement fixing ability of anti-liver kidney microsomal antibody (anti-LKM) in the sera of six children and five adults with autoimmune chronic active hepatitis (aCAH), Anti-LKM titres ranged from 1/80 to 20,480. In the children, the antibody belonged to the IgG1 subclass alone (titre l/80-1/20,480) and was able to fix complement (titre 1/40 -1/5120). In the adult group, antibody belonged to the IgG1 subclass in three cases (titre 1 40-1 640 whilst two belonged to both IgG1 (titre 1/640) and lgG4 (titre 1/40, 1/640). Such subclass restriction is similar to that found in other autoimmune disorders and may be genetically determined. Investigation of' the light chain constituent of anti-LKM revealed that the kappa to lambda ratio was consistent with a polyclonal antibody response. To investigate the nature of the antigen to which anti-LKM is directed, the ability of these sera to bind to the surface membrane of isolated human hepatoma cells (Alexander cells) was investigated. Four of the eleven sera showed significant binding activity. Prior incubation of these four sera with Alexander cells abolished their membrane binding activity, but did not alter the anti-LKM titre. These results suggest that anti-LKM binds to cytoplasmic constituents alone and does not cross-react with surface antigens. [ABSTRACT FROM AUTHOR]

Con A stimulated suppressor cell function and the proportion of suppressor T cells were reduced in children with untreated chronic active hepatitis (CAH) but were normal in corticosteroid treated CAH patients, patients with severe acute hepatitis and inactive chronic liver disease. Adults with CAH also have defective suppressor function hut a normal proportion of T suppressor cells. This difference may account for the observation that relapse after treatment withdrawal is less frequent in children than in adults. [ABSTRACT FROM AUTHOR]

Proportion of T cell subsets, spontaneous and PWM stimulated immunoglobulin production by peripheral blood lymphocytes and concanavalin A- (Con A) stimulated suppressor cell activity on immunoglobulin production by B cells was studied in 37 infants and children, to investigate changes of these parameters with age. Proportion of suppressor/cytotoxic (T8+) T lymphocytes was significantly lower in children below the age of 5 years, while there was no difference in proportion of total T lymphocytes (T3+) and helper/inducer (T4+) T cells. Spontaneous production and secretion of IgG and IgM by lymphocytes from children of all age groups was similar to that found in adults, but lymphocytes of children below the age of 10 years showed a low response to PWM stimulation. The activity of Con A-induced suppressor cells in inhibiting B cells producing immunoglobulins was almost absent in infancy, gradually increased during childhood and reached adult levels in teenagers. A significant association between the proportion of T8+ cells and Con A-induced suppression of B cell proliferation and a relationship between T4+ cells and spontaneous Ig production indicated the increasing maturity with respect to both number and function of peripheral blood lymphocyte subsets with advancing age. [ABSTRACT FROM AUTHOR]

In a micrototoxicity assay, lymphocytes from ten out of sixteen patients with HBsAg-negative chronic active hepatitis have been shown to be cytotoxic to autologous hepatocytes isolated from percutaneous liver biopsies. This cytotoxicity was demonstrable in all six untreated patients but in only four out of ten receiving immunosuppressive treatment, the presence of cytotoxicity showing a significant association with the activity of the disease assessed histologically. The addition of excess purified lipoprotein (LSP), derived from the hepatocyte plasma membrane, blocked the reaction in all cytotoxic cases, indicating that LSP was the major target antigen. Enriched fractions of T cells were cytotoxic in only one case, whereas non-T cell fractions were cytotoxic in the other ten cases investigated in this way. For optimum T cell cytotoxicity, effector and target cells must share histocompatibility determinants and the results of this study using an autologous system show conclusively that the lymphocyte cytotoxicity found in HBsAg-negative chronic active hepatitis is mediated by a non-T cell population. [ABSTRACT FROM AUTHOR]

Examines the occurrence of halothane hepatitis in children. Diagnosis of the disease; Causes of liver diseases; Interval between the final halothane exposure and the onset of jaundice.

To assess whether clinicopathological features other than the age at operation influence prognosis after surgery for extrahepatic biliary atresia (EHBA) and to determine whether the age at referral has fallen since a previous survey, 50 consecutive cases with EHBA referred between February, 1985, and December, 1987, were reviewed. Liver or spleen size, liver function tests, or histological appearance of liver biopsy specimen before surgery were not predictive of outcome. The jaundice cleared up in 12 of 14 children operated on by age 8 weeks, but in only 13 of 36 operated on later. In 41 referral was delayed. All 25 children in whom surgery was successful are alive and well, while 13 of 25 with unsuccessful surgery have died, at a median age of 1 year. To improve the prognosis of infants with EHBA parents and health staff need a better awareness of the early clinical features of EHBA and of the necessity for prompt referral. Liver disease should be suspected in any infant jaundiced after 14 days of age. [ABSTRACT FROM AUTHOR]