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S Parsons

Publications and source records attributed to S Parsons.

At least 37 records · Page 2Linked to original sources
PubMed2001

High-pressure single-crystal X-ray diffraction facilities on station 9.8 at the SRS Daresbury Laboratory--hydrogen location in the high-pressure structure of ethanol.

A new high-pressure single-crystal diffraction facility has been constructed on station 9.8 at the Synchrotron Radiation Source, Daresbury Laboratory, for a range of studies on a variety of systems of relevance to physics, chemistry and materials science that would otherwise prove intractable with conventional laboratory-based methods. The station has been equipped with a modified Enraf-Nonius CAD4 four-circle diffractometer for high-pressure studies which can be conveniently, and rapidly, interchanged with the Bruker SMART CCD area-detector system when more routine ambient-pressure diffraction work is to be undertaken. This rapid change-over has been achieved by permanently mounting the CAD4 on its own jacking table, formerly used for the station's white-beam diffraction mode, which allows the alignment of the SMART diffractometer to remain undisturbed when the CAD4 is in use. Early results on the test low-melting-point compound ethanol (CH3CH2OH) reveal that excellent refined structures can be obtained, including the location and refinement of the H atoms, demonstrating that one of the original, and major, objectives of the station has been accomplished.

Ethanol↗
PubMed2001

Anxiety and depression in mothers of children undergoing bone marrow transplant: symptom prevalence and use of the Beck depression and Beck anxiety inventories as screening instruments.

This study examined anxiety and depressive symptoms among 115 mothers of children undergoing bone marrow transplant and evaluated the ability of the Beck Anxiety Inventory (BAI; A. T. Beck, N. Epstein, et al., 1988) and the Beck Depression Inventory (BDI; A. T. Beck, 1978) to serve as screening tools for assessing generalized anxiety disorder (GAD), panic disorder (PD), and major depressive disorder (MDD). Mothers with BAI or BDI scores greater than or equal to 14 were administered a structured clinical interview. An additional 20% was randomly selected for interview to determine whether the scale cutoff was an accurate screening method. Among the 64 mothers interviewed, 20% received at least I of the 3 diagnoses. Although the BAI did not demonstrate predictive accuracy in assessing GAD and PD, the BDI did in assessing MDD. The results suggest that a subset of mothers may have an anxiety or depressive disorder and that investigators should use caution before using the BAI as a screening instrument for anxiety disorder.

Adolescent↗
PubMed2001

catena-Poly[[trans-dichlorocopper(II)-mu-1,4,7,10,13,16-hexathiacyclooctadecane-S1:S10].

In the title complex, [CuCl2(C12H24S6)]n, the CuCl2 unit and the ligand lie on and about inversion centres, respectively. The coordination geometry at CuII is a tetragonally elongated octahedron with the equatorial positions occupied by two chlorides, Cu-Cl 2.2786 (12) A, and two S donors, Cu-S 2.3710 (13) A. The apical positions of the octahedron are defined by two S donors at distances of 2.8261 (14) A from the metal. The macrocyclic ligand adopts a very puckered and distorted conformation. Eight of the 18 torsion angles are less than 90 degrees and all S-donors are oriented exo to the ring.

Journal Article↗
PubMed2001

The teaching of health care ethics to students of nursing in the UK: a pilot study.

Senior lecturers/lecturers in mental health nursing (11 in round one, nine in round two, and eight in the final round) participated in a three-round Delphi study into the teaching of health care ethics (HCE) to students of nursing. The participants were drawn from six (round one) and four (round three) UK universities. Information was gathered on the organization, methods used and content of HCE modules. Questionnaire responses were transcribed and the content analysed for patterns of interest and areas of convergence or divergence. Findings include: the majority (72.8%) of the sample believed that insufficient time was allocated to the teaching of HCE; case studies were considered a popular, although problematic, teaching method; the 'four principles' approach was less than dominant in the teaching of HCE; and virtue ethics was taught by only 36.4% of the participants. The Delphi technique proved adequate and worth while for the purposes of this study. Further empirical research could aim to replicate or contradict these findings, using a larger sample and recruiting more university departments. Reflection is required on several issues, including the depth and breadth to which ethics theory and, more controversially, meta-ethics, are taught to nursing students.

Adult↗
PubMed2000

Preparation, X-ray crystal structure determination, lattice potential energy, and energetics of formation of the salt S4(AsF6)2.AsF3 containing the lattice-stabilized tetrasulfur [2+] cation. Implications for the understanding of the stability of M(4)2+ and M2+ (M = S, Se, and Te) crystalline salts.

S4(AsF6)2.AsF3 was prepared by the reaction of sulfur with arsenic pentafluroide in liquid AsF3 (quantitatively) and in anhydrous HF in the presence of trace amounts of bromine. A single-crystal X-ray structure of the compound has been determined: monoclinic, space group P2(1)/c, Z = 4, a = 7.886(1) A, b = 9.261(2) A, c = 19.191(3) A, beta = 92.82(1) degrees, V = 1399.9(4) A3, T = 293 K, R1 = 0.052 for 1563 reflections (I > 2 sigma (I) 1580 total and 235 parameters). We report a term-by-term calculation of the lattice potential energy of this salt and also use our generalized equation, which estimates lattice energies to assist in probing the homopolyatomic cation thermochemistry in the solid and the gaseous states. We find S4(AsF6)2.AsF3 to be more stable (delta fH degree [S4(AsF6)2.AsF3,c] approximately -4050 +/- 105 kJ/mol) than either the unsolvated S4(AsF6)2 (delta fH degree [S4(AsF6)2,c] approximately -3104 +/- 117 kJ/mol) by 144 kJ/mol or two moles of S2AsF6 (c) and AsF3 (1) by 362 kJ/mol. The greater stability of the S(4)2+ salt arises because of the greater lattice potential energy of the 1:2 solvated salt (1734 kJ/mol) relative to twice that of the 1:1 salt (2 x 541 = 1082 kJ/mol). The relative lattice stabilization enthalpies of M(4)2+ ions relative to two M2+ ions (i.e., in M4(AsF6)2 (c) with respect to two M2AsF6 (c) (M = S, Se, and Te)) are found to be 218, 289, and 365 kJ/mol, respectively. Evaluation of the thermodynamic data implies that appropriate presently available anions are unlikely to stabilize M2+ in the solid phase. A revised value for delta fH degree [Se4(AsF6)2,c] = -3182 +/- 106 kJ/mol is proposed based on estimates of the lattice energy of Se4(AsF6)2 (c) and a previously calculated gasphase dimerization energy of 2Se2+ to Se(4)2+.

Journal Article↗
PubMed2000

Elucidating the mode of action of a corrosion inhibitor for iron

Two polymetallic iron(III) complexes 1 and 2 have been synthesised from the known corrosion inhibitor 3-(4-methylbenzoyl)-propionic acid HL1 and their crystal structures determined. Coordination geometries extracted from these structures have been used as the basis for molecular modelling onto idealised iron(III) oxide surfaces as an aid to understanding the efficacy of inhibitors of the 4-keto acid type. The proposed mode of action involves 1,3-bridging didentate coordination of the carboxylate function of L1 to two FeIII ions, hydrogen-bond formation between the 4-keto group of L1 and a bridging surface hydroxy group, as well as close packing of the aromatic end groups, which should generate a hydrophobic barrier on the surface. Adsorption isotherm experiments have been used to compare the strengths of binding of related carboxylic acids onto iron(III) oxide surfaces and indicate that the presence of the 4-keto function leads to the formation of significantly more stable surface complexes.

Journal Article↗
PubMed2000

A family of polynuclear cobalt and nickel complexes stabilised by 2-pyridonate and carboxylate ligands

The synthesis and structural characterisation of a series of cobalt and nickel cages are reported. Eight of these structures contain a [M10(mu3-OH)6(eta2, mu3-xhp),(eta2, mu2-O2CR)6]2+ core (where M = Co or Ni; xhp = 6-chloro- or 6-methyl-2-pyridonate: R = Me, Ph, CHMe2, CH2Cl, CHPh2 or CMe3), where the ten metal atoms describe a centred-tricapped-trigonal prism (ttp). The cage contains six hydroxide ligands around the central metal, and the exterior is coated with pyridonate and carboxylate ligands. For four of the cages additional metal centres are found attached to the upper and/or lower triangular faces of the trigonal prism, generating dodeca- and undecanuclear cages. Three further cages are reported that contain a metal core based on an incomplete centred-tetraicosahedron. These cages involve trimethylacetate as a ligand in company with either 6-methyl-2-pyridonate or 6-chloro-2-pyridonate. Comparison of these latter structures with the trigonal prisms reveal that they can be described as a pentacapped-trigonal prism missing one edge. Magnetic studies of three of the nickel cages with trigonal prismatic cores show spin ground states of S = 8, 4 and 2 for Ni12, Ni11 and Ni10 cages, respectively.

Journal Article↗
PubMed2000

Developmental changes in the transmitter properties of sympathetic neurons that innervate the periosteum.

During the development of sweat gland innervation, interactions with the target tissue induce a change from noradrenergic to cholinergic and peptidergic properties. To determine whether the change in neurotransmitter properties that occurs in the sweat gland innervation occurs more generally in sympathetic neurons, we identified a new target of cholinergic sympathetic neurons in rat, the periosteum, which is the connective tissue covering of bone, and characterized the development of periosteal innervation of the sternum. During development, sympathetic axons grow from thoracic sympathetic ganglia along rib periosteum to reach the sternum. All sympathetic axons displayed catecholaminergic properties when they reached the sternum, but these properties subsequently disappeared. Many axons lacked detectable immunoreactivities for vesicular acetylcholine transporter and vasoactive intestinal peptide when they reached the sternum and acquired them after arrival. To determine whether periosteum could direct changes in the neurotransmitter properties of sympathetic neurons that innervate it, we transplanted periosteum to the hairy skin, a noradrenergic sympathetic target. We found that the sympathetic innervation of the transplant underwent a noradrenergic to cholinergic and peptidergic change. These results suggest that periosteum, in addition to sweat glands, regulates the neurotransmitter properties of the sympathetic neurons that innervate it.

Animals↗
PubMed2000

Stereoselective formation of seven-coordinate titanium(IV) monomer and dimer complexes of ethylenebis(o-hydroxyphenyl)glycine.

Reactions between the antitumor agent titanocene dichloride (Cp2TiCl2) and the hexadentate ligand N,N'-ethylenebis-(o-hydroxyphenylglycine) (H4ehpg) have been investigated in aqueous solution and the solid state. The racemic ligands give crystals of the monomer [Ti(ehpg)(H2O)] x (11/3)H2O (1), while the meso ligand gives the oxo-bridged dimer [[Ti(Hehpg)(H2O)]2O] x 13H2O (2). Complex 1 crystallizes in the monoclinic space group C2/c with a = 24.149(4) A, b = 14.143(3) A, c = 19.487(3) A, beta = 105.371(13) degrees, V = 6417.7(19) A3, Z = 12, and R(F) = 0.0499 for 4,428 independent reflections having I > 2sigma(I), and contains seven-coordinate pentagonal-bipyramidal TiIV with two axial phenolate ligands (Ti-O, 1.869(2) A). The pentagonal plane contains the two N-atoms at 2.210(2) A, two carboxylate O-atoms at 2.061(2) A, and a water molecule (Ti-OH2, 2.091(3) A). Complex 2 crystallizes as an oxygen-bridged dimer in the triclinic space group P-1 with a = 12.521(6) A, b = 14.085(7) A, c = 16.635(8) A, alpha = 80.93(2) degrees beta = 69.23(2) degrees, gamma = 64.33(2) degrees , V = 2472(2) A3, Z = 4, and R(F) = 0.0580 for 5956 independent reflections having I > 2sigma(I). Each seven-coordinate, pentagonal-bipyramidal TiIV has a bridging oxide and a phenolate as axial ligands. The pentagonal plane donors are H2O, two carboxylate O-atoms, and two NH groups, which form H-bonds to O-atoms both in the same half-molecule (O...N, 2.93-3.13 A) and in the other half-molecule (O...N, 2.73-2.75 A); the second phenoxyl group of each Hehpg ligand is protonated and not coordinated to TiIV, but H-bonds to a nearby amine proton (O...N, 2.73-2.75 A) from the same ligand and to a nearby H2O (O...O, 2.68 A). In contrast to all previously reported crystalline metal-EHPG complexes containing racemic ligands, in which the N(S,S)C(R,R) or N(R,R)C(S,S) form is present, complex 1 unexpectedly contains the N(S,S)C(S,S) and N(R,R)C(R,R) forms. This is attributed to the presence of ring strain in seven-coordinate TiIV complexes. Moreover, the rac ligands selectively form crystals of monomeric 1, while the meso ligand selectively forms crystals of the dimer 2 (N(R,R)C(R,S) or N(S,S)C(S,R)). Complexes 1 and 2 exhibit phenolate-to-TiIV charge-transfer bands near 387 nm, and 2D NMR studies indicate that the structures of 1 and 2 in solution are similar to those in the solid state. Complex 1 is stable over the pH range 1.0-7.0, while 2 is stable only between pH 2.5 and pH 5.5. Cp2TiCl2 reacts with EHPG at pH* 7.0 to give complex 1 with a t 1/2 of ca. 50 min (298 K), but complex 2 was not formed at this pH* value. At pH* 3.7, the reaction is very slow: 1 forms with a half-life of ca. 2.5 d, and 2 after ca. 1 week at ambient temperature. The relevance of these data to the possible role of serum transferrin as a mediator for the delivery of TiIV to tumor cells is discussed.

Antineoplastic Agents↗
PubMed2000

The Phil Hearne course: an evaluation of a multidisciplinary mental health education programme for clinical practitioners.

A description and evaluation of the pilot of a 30-week multidisciplinary mental health education programme (The Phil Hearne Course) is presented. The course was based upon the expressed service needs of an NHS Trust and upon the needs of users consulted during the developmental phase of the project. The course was designed to provide core skills, relating to effective assessment, communication, intervention and networking. These skills were thought to be applicable to all mental health disciplines. The course was evaluated positively by students and staff and was found to be effective in improving practice by providing a range of core skills for mental health workers. It was also determined that students tended to over-estimate their skills in core areas, particularly care planning and record-keeping. It is intended to develop the course into a distance learning, skills-based package.

Education, Nursing, Continuing↗
PubMed2000

2-Amino-5-chloro-1,3-benzoxazol-3-ium 2-(3,4-dichlorophenoxy)acetate.

The 1:1 organic salt of the title compound, C(7)H(6)ClN(2)O(+). C(8)H(5)Cl(2)O(3)(-) or [(2-ABOX)(3,4-D)], comprises the two constituent molecules associated by an R(2)(2)(8) graph-set interaction through the carboxylate group of 3,4-D across the protonated N/N sites of 2-ABOX [N.O 2.546 (3) and 2.795 (3) A]. Cation/anion pairs associate across an inversion centre forming discrete tetramers via an additional three-centre hydrogen-bonding association from the latter N amino proton to a phenoxy O atom [N.O 3.176 (3) A] and a carboxylate O atom [N.O 2.841 (3) A]. This formation differs from the polymeric hydrogen-bonded chains previously observed for adduct structures of 2-ABOX with carboxylic acids.

Acetates↗