bluuebunny/crossref_metadata_2025 huggingface dataset:
Auger Electron Spectra of Sodium Bound to Keratin and other Biological Materials
Authors: Astrid Höglund  , Erik Odeblad
Published: January 2007

It is expected that keratin, the protective protein of the skin, has capability to bind materials for which it is exposed e.g. inorganic ions. To test this hypothesis for sodium ions we studied the Na Auger 1
D line in NaCl-keratin combinations. The keratin methylene C-1s line served as an internal reference and the shift, S, to the Na 1
D line was measured. It was found that S was dependent on P, the molar fraction of NaCl (on a NaCl-peptide bond basis). The experimental values suggest that S depends on P according to the eq.:

S = 13.0-3.2√P

with S expressed in eV. This result indicates the following: (1) There exists some kind of bonding, or association, between NaCl and keratin. (2) NaCl seems to be associated to the peptide regions of the protein. (3) The bonding is second order in the sense that (probably) two moles of bonds occur per mole NaCl. (4) Possible models can be presented for the mechanisms involved and it is tentatively suggested that electrostatic bonding occurs between Na+ and the carbonyl oxygen and, under certain circumstances, between Cl- and the nitrogen of the peptide bond. Besides keratin, a number of other biochemicals and cervical mucus were studied. Cervical mucus associates, according to our experimental findings, sodium chloride, probably in a similar fashion. This has diagnostic interest in human fertility problems. It is not yet known which of the constituents in the cervical mucus that is mainly responsible for the bonding, and this and several other related questions are the subject of continued studies.
Satellites in ESCA Spectra of Cu2+ Compounds
Authors: Sven Larsson  , E Odeblad
Published: January 2007

Equations are proposed which relate spin density to intensity ratio and width of interatomic shake-up satellites in the 2p region in ESCA spectra of Cu(II) compounds. In a number of cases these equations are followed. In other cases two distinct satellites appear in the 2p
1/2 as well as in the 2p
3/2 region.
Photoemission from Noble Metals and Adsorbates using Synchrotron Radiation
Authors: D A Shirley  , J Stöhr  , P S Wehner  , R S Williams  , G Apai
Published: January 2007

With the advent of synchrotron radiation in the 32-280 eV range at the Stanford Synchrotron Radiation Project, it has become possible to elucidate the transition from ultraviolet to X-ray-induced photoemission. This has been accomplished by studies of noble metals. Polycrystalline copper shows a valence-band (VB) profile that approaches the X-ray induced shape athv∼ 100 eV. In polycrystalline silver, the 4dcross section follows the atomic curve, with a reversal of VB peak intensities nearhv= 110 eV. Strongly anisotropic behavior is observed in copper single crystals, using angle-resolved photoemission (ARP). Normal ARP spectra from Cu(100), (110), and (111) crystals follow the band dispersion through the Brillouin Zone, including a dramatic resonance between the Fermi level (EF) and 2 eV binding energy forhv= 43-52 eV. High temperature and high photon energy studies demonstrate the importance of the Debye-Waller factor in photoemission leading to a breakdown of the direct transition model. In adsorption studies of CO on Ni and Pt, CO is shown to stand up with oxygen out. For Pt, electrons are found to flow fromt2gorbitals nearEFto CO, and the CO 1π and 5σ binding energies are reversed relative to the gas phase. At higher photon energies,hv= 150 eV, the CO orbitals are very prominent on a Pt substrate. An inversion of the angular distribution of these orbitals and energy-dependent resonances in their intensities provide evidence for final state scattering effects at photon energies above 40 eV.
The Electronic Structure of PbSe and Its Interaction with O2Adsorbate Layers
Authors: A L Hagström  , A Fahlman
Published: January 2007

Clean and O2exposed surfaces of PbSe have been studied by UV and X-ray photoelectron spectroscopy. The O2reaction was found to be quite slow. Considerations regarding relative peak intensities of the core levels indicated a diffusion of oxygen into the lattice. The sticking coefficient of O2was estimated to be of the order of 10-10-10-11.
Solid State Effects in the Auger Electron Spectra of Magnesium, Zinc and Cadmium
Authors: J Väyrynen  , S Aksela  , H Aksela
Published: January 2007

High resolutionKLLAuger electron spectrum from magnesium,L2,3M4,5M4,5spectrum from zinc, andM4,5N4,5N4,5spectrum from cadmium have been measured for both vapour and solid phases using electron impact excitation. In order to observe in detail solid state effects in these Auger spectra and to minimize the contribution of instrumental differences, the measurements for the two phases were carried out with the same spectrometer. From decomposition of the line groups into individual lines was obtained line broadening on going from vapour to solid, (0.20 ± 0.10) eV for magnesium, (0.45 ± 0.10) eV for zinc and (0.47 ± 0.10) eV for cadmium. The kinetic energy shifts of the line components between vapour and solid were found to be (16.0 ± 0.5) eV, (13.7 ± 0.5) eV, and (12.2 ± 0.5) eV for magnesium, zinc, and cadmium, respectively. The calculated vapour-metal Auger energy shifts using Shirley's extra-atomic relaxation model are in agreement with our experimental results.
Investigation of the Effect Produced by Short-range and Long-range Order on the Spectrum of Valence Electrons in Solids
Authors: V V Nemoshkalenko  , V G Aleshin
Published: January 2007

X-ray photoelectron spectra of valence and core electrons are obtained for AgI, Ag2S, Ag2Se, Ag2Te, Ag2HgI4, Cu2HgI4and Cu2S–compounds which reveal a lattice instability at temperature increase. X-ray photoelectron spectra of valence and core electrons in the chalkogenides AgAsS2, AgSbS2, and AsGeS in crystalline and glass-like states were studied. For AsGeS in crystalline and glass-like state the X-ray emissionLII,III-spectra of sulphur were investigated.K- andLII,III-emission spectra of pure sulphur were also obtained. When the compounds go from the crystalline state into the α-phase, a smoothing takes place of structural singularities in the photoelectron spectra in the region of energy localization of the states of the non-metallic components. The structural singularities are clearly resolved in the X-ray photoelectron spectra of AgAsS2and AgSbS2crystals but are smoothed in the spectra of the glass-like state. The X-ray photoelectron spectrum of the glass-like state has two maxima near the valence band top while the spectrum of the crystal has only one maximum. For AsGeS in its glass-like state the singularities of the fine structure observed in theLII,III-emission spectrum of sulphur are less pronounced than in the corresponding spectrum of the crystalline state. When the investigated compounds of Ag and Cu go from the crystalline state into the α-phase and when the chalcogenides AgAsS2, AgSbS2, and AsGeS are transferred from the crystalline into the glass-like state the atom charge state does not undergo perceptible changes. The alterations observed in the X-ray photoelectron spectra when compounds transfer from a crystalline state into one with a lattice instability or into a glass-like state are due to the effect produced on the energy structure of valence electrons by the short- and long-range order in the arrangement of atoms of metal and nonmetal components in the compound.
ESCA Studies of the Clean Si (111) Surface
Authors: N E Erickson
Published: January 2007

The angular variation of elastically scattered electrons excited by X-rays from various electron levels of silicon and surface or near surface impurity atoms of nickel and gold are reported. The valence band profile of the Si (111) surface is presented as a function of electron take-off angle. Evidence is presented that the Si(2p) binding energy is dependent on the crystal surface geometrical ordering. A discussion of some of the implications of these studies is presented.
Parametrization of local CR automorphisms by finite jets and applications
Authors: Lamel Bernhard , Mir Nordine
Published: January 2007

For any real-analytic hypersurface

M
⊂

C

N

M\subset \mathbb {C}^N

, which does not contain any complex-analytic subvariety of positive dimension, we show that for every point

p
∈
M

p\in M

the local real-analytic CR automorphisms of

M
M

fixing

p
p

can be parametrized real-analytically by their

ℓ
p

\ell _p

jets at

p
p

. As a direct application, we derive a Lie group structure for the topological group

Aut
⁡
(
M
,
p
)

\operatorname {Aut}(M,p)

. Furthermore, we also show that the order

ℓ
p

\ell _p

of the jet space in which the group

Aut
⁡
(
M
,
p
)

\operatorname {Aut}(M,p)

embeds can be chosen to depend upper-semicontinuously on

p
p

. As a first consequence, it follows that given any compact real-analytic hypersurface

M
M

in

C

N

\mathbb {C}^N

, there exists an integer

k
k

depending only on

M
M

such that for every point

p
∈
M

p\in M

germs at

p
p

of CR diffeomorphisms mapping

M
M

into another real-analytic hypersurface in

C

N

\mathbb {C}^N

are uniquely determined by their

k
k

-jet at that point. Another consequence is the following boundary version of H. Cartan’s uniqueness theorem: given any bounded domain

Ω
\Omega

with smooth real-analytic boundary, there exists an integer

k
k

depending only on

∂
Ω

\partial \Omega

such that if

H
:
Ω
→
Ω

H\colon \Omega \to \Omega

is a proper holomorphic mapping extending smoothly up to

∂
Ω

\partial \Omega

near some point

p
∈
∂
Ω

p\in \partial \Omega

with the same

k
k

-jet at

p
p

with that of the identity mapping, then necessarily

H
=

Id

H=\textrm {Id}

. Our parametrization theorem also holds for the stability group of any essentially finite minimal real-analytic CR manifold of arbitrary codimension. One of the new main tools developed in the paper, which may be of independent interest, is a parametrization theorem for invertible solutions of a certain kind of singular analytic equations, which roughly speaking consists of inverting certain families of parametrized maps with singularities.
Large character sums: Pretentious characters and the Pólya-Vinogradov theorem
Authors: Granville Andrew , Soundararajan K.
Published: January 2007

In 1918 Pólya and Vinogradov gave an upper bound for the maximal size of character sums, which still remains the best known general estimate. One of the main results of this paper provides a substantial improvement of the Pólya-Vinogradov bound for characters of odd, bounded order. In 1977 Montgomery and Vaughan showed how the Pólya-Vinogradov inequality may be sharpened assuming the Generalized Riemann Hypothesis. We give a simple proof of their estimate and provide an improvement for characters of odd, bounded order. The paper also gives characterizations of the characters for which the maximal character sum is large, and it finds a hidden structure among these characters.
Supercuspidal representations: An exhaustion theorem
Authors: Kim Ju-Lee
Published: January 2007

Let

G
G

be a reductive

p
p

-adic group. We prove that all supercuspidal representations of

G
G

arise through Yu’s construction subject to certain hypotheses on

k
k

(depending on

G
G

). As a corollary, under the same hypotheses, we see that any supercuspidal representation is compactly induced from a representation of an open subgroup which is compact modulo the center.
Sieving by large integers and covering systems of congruences
Authors: Filaseta Michael , Ford Kevin , Konyagin Sergei , Pomerance Carl , Yu Gang
Published: January 2007

An old question of Erdős asks if there exists, for each number

N
N

, a finite set

S
S

of integers greater than

N
N

and residue classes

r
(
n
)
 
(

mod

 
n
)

r(n)~(\textrm {mod}~n)

for

n
∈
S

n\in S

whose union is

Z

\mathbb Z

. We prove that if

∑

n
∈
S

1

/

n

\sum _{n\in S}1/n

is bounded for such a covering of the integers, then the least member of

S
S

is also bounded, thus confirming a conjecture of Erdős and Selfridge. We also prove a conjecture of Erdős and Graham, that, for each fixed number

K
>
1

K>1

, the complement in

Z

\mathbb Z

of any union of residue classes

r
(
n
)
 
(

mod

 
n
)

r(n)~(\textrm {mod}~n)

, for distinct

n
∈
(
N
,
K
N
]

n\in (N,KN]

, has density at least

d
K

d_K

for

N
N

sufficiently large. Here

d
K

d_K

is a positive number depending only on

K
K

. Either of these new results implies another conjecture of Erdős and Graham, that if

S
S

is a finite set of moduli greater than

N
N

, with a choice for residue classes

r
(
n
)
 
(

mod

 
n
)

r(n)~(\textrm {mod}~n)

for

n
∈
S

n\in S

which covers

Z

\mathbb Z

, then the largest member of

S
S

cannot be

O
(
N
)

O(N)

. We further obtain stronger forms of these results and establish other information, including an improvement of a related theorem of Haight.
Cornichon-like Protein Facilitates Secretion of HB-EGF and Regulates Proper Development of Cranial Nerves
Authors: Hoshino Hideharu , Uchida Tsukasa , Otsuki Toshiaki , Kawamoto Shoko , Okubo Kousaku , Takeichi Masatoshi , Chisaka Osamu
Published: January 2007

During their migration to the periphery, cranial neural crest cells (NCCs) are repulsed by an ErbB4-dependent cue(s) in the mesenchyme adjoining rhombomeres (r) 3 and 5, which are segmented hindbrain neuromeres. ErbB4 has many ligands, but which ligand functions in the above system has not yet been clearly determined. Here we found that a cornichon-like protein/cornichon homolog 2 (CNIL/CNIH2) gene was expressed in the developing chick r3 and r5. In a cell culture system, its product facilitated the secretion of heparin-binding epidermal growth factor-like growth factor (HB-EGF), one of the ligands of ErbB4. When CNIL function was perturbed in chick embryos by forced expression of a truncated form of CNIL, the distribution of NCCs was affected, which resulted in abnormal nerve fiber connections among the cranial sensory ganglia. Also, knockdown of CNIL or HB-EGF with siRNAs yielded a similar phenotype. This phenotype closely resembled that of ErbB4 knockout mouse embryos. Because HB-EGF was uniformly expressed in the embryonic hindbrain, CNIL seems to confine the site of HB-EGF action to r3 and r5 in concert with ErbB4.
Genetic Control of Fusion Pore Expansion in the Epidermis ofCaenorhabditis elegans
Authors: Gattegno Tamar , Mittal Aditya , Valansi Clari , Nguyen Ken C.Q. , Hall David H. , Chernomordik Leonid V. , Podbilewicz Benjamin
Published: January 2007

Developmental cell fusion is found in germlines, muscles, bones, placentae, and stem cells. In Caenorhabditis elegans 300 somatic cells fuse during development. Although there is extensive information on the early intermediates of viral-induced and intracellular membrane fusion, little is known about late stages in membrane fusion. To dissect the pathway of cell fusion in C. elegans embryos, we use genetic and kinetic analyses using live-confocal and electron microscopy. We simultaneously monitor the rates of multiple cell fusions in developing embryos and find kinetically distinct stages of initiation and completion of membrane fusion in the epidermis. The stages of cell fusion are differentially blocked or retarded in eff-1 and idf-1 mutants. We generate kinetic cell fusion maps for embryos grown at different temperatures. Different sides of the same cell differ in their fusogenicity: the left and right membrane domains are fusion-incompetent, whereas the anterior and posterior membrane domains fuse with autonomous kinetics in embryos. All but one cell pair can initiate the formation of the largest syncytium. The first cell fusion does not trigger a wave of orderly fusions in either direction. Ultrastructural studies show that epidermal syncytiogenesis require eff-1 activities to initiate and expand membrane merger.
NHERF Links the N-Cadherin/Catenin Complex to the Platelet-derived Growth Factor Receptor to Modulate the Actin Cytoskeleton and Regulate Cell Motility
Authors: Theisen Christopher S. , Wahl James K. , Johnson Keith R. , Wheelock Margaret J.
Published: January 2007

Using phage display, we identified Na+/H+ exchanger regulatory factor (NHERF)-2 as a novel binding partner for the cadherin-associated protein, β-catenin. We showed that the second of two PSD-95/Dlg/ZO-1 (PDZ) domains of NHERF interacts with a PDZ-binding motif at the very carboxy terminus of β-catenin. N-cadherin expression has been shown to induce motility in a number of cell types. The first PDZ domain of NHERF is known to bind platelet-derived growth factor-receptor β (PDGF-Rβ), and the interaction of PDGF-Rβ with NHERF leads to enhanced cell spreading and motility. Here we show that β-catenin and N-cadherin are in a complex with NHERF and PDGF-Rβ at membrane ruffles in the highly invasive fibrosarcoma cell line HT1080. Using a stable short hairpin RNA system, we showed that HT1080 cells knocked down for either N-cadherin or NHERF had impaired ability to migrate into the wounded area in a scratch assay, similar to cells treated with a PDGF-R kinase inhibitor. Cells expressing a mutant NHERF that is unable to associate with β-catenin had increased stress fibers, reduced lamellipodia, and impaired cell migration. Using HeLa cells, which express little to no PDGF-R, we introduced PDGF-Rβ and showed that it coimmunoprecipitates with N-cadherin and that PDGF-dependent cell migration was reduced in these cells when we knocked-down expression of N-cadherin or NHERF. These studies implicate N-cadherin and β-catenin in cell migration via PDGF-R–mediated signaling through the scaffolding molecule NHERF.
Avl9p, a Member of a Novel Protein Superfamily, Functions in the Late Secretory Pathway
Authors: Harsay Edina , Schekman Randy
Published: January 2007

The branching of exocytic transport routes in both yeast and mammalian cells has complicated studies of the late secretory pathway, and the mechanisms involved in exocytic cargo sorting and exit from the Golgi and endosomes are not well understood. Because cargo can be sorted away from a blocked route and secreted by an alternate route, mutants defective in only one route do not exhibit a strong secretory phenotype and are therefore difficult to isolate. In a genetic screen designed to isolate such mutants, we identified a novel conserved protein, Avl9p, the absence of which conferred lethality in a vps1Δ apl2Δ strain background (lacking a dynamin and an adaptor-protein complex 1 subunit). Depletion of Avl9p in this strain resulted in secretory defects as well as accumulation of Golgi-like membranes. The triple mutant also had a depolarized actin cytoskeleton and defects in polarized secretion. Overexpression of Avl9p in wild-type cells resulted in vesicle accumulation and a post-Golgi defect in secretion. Phylogenetic analysis indicated evolutionary relationships between Avl9p and regulators of membrane traffic and actin function.
Some predictions of the attached eddy model for a high Reynolds number boundary layer
Authors: Nickels T.B , Marusic I , Hafez S , Hutchins N , Chong M.S
Published: January 2007

Many flows of practical interest occur at high Reynolds number, at which the flow in most of the boundary layer is turbulent, showing apparently random fluctuations in velocity across a wide range of scales. The range of scales over which these fluctuations occur increases with the Reynolds number and hence high Reynolds number flows are difficult to compute or predict. In this paper, we discuss the structure of these flows and describe a physical model, based on the attached eddy hypothesis, which makes predictions for the statistical properties of these flows and their variation with Reynolds number. The predictions are shown to compare well with the results from recent experiments in a new purpose-built high Reynolds number facility. The model is also shown to provide a clear physical explanation for the trends in the data. The limits of applicability of the model are also discussed.
Multiple small RNAs act additively to integrate sensory information and control quorum sensing in Vibrio harveyi
Authors: Tu Kimberly C. , Bassler Bonnie L.
Published: January 2007

Quorum sensing is a cell–cell communication mechanism that bacteria use to collectively regulate gene expression and, at a higher level, to coordinate group behavior. In the bioluminescent marine bacterium Vibrio harveyi, sensory information from three independent quorum-sensing systems converges on the shared response regulator LuxO. When LuxO is phosphorylated, it activates the expression of a putative repressor that destabilizes the mRNA encoding the master quorum-sensing transcriptional regulator LuxR. In the closely related species Vibrio cholerae, this repressor was revealed to be the RNA chaperone Hfq together with four small regulatory RNAs (sRNAs) called Qrr1–4 (quorum regulatory RNA). Here, we identify five Qrr sRNAs that control quorum sensing in V. harveyi. Mutational analysis reveals that only four of the five Qrrs are required for destabilization of the luxR mRNA. Surprisingly, unlike in V. cholerae where the sRNAs act redundantly, in V. harveyi, the Qrr sRNAs function additively to control quorum sensing. This latter mechanism produces a gradient of LuxR that, in turn, enables differential regulation of quorum-sensing target genes. Other regulators appear to be involved in control of V. harveyi qrr expression, allowing the integration of additional sensory information into the regulation of quorum-sensing gene expression.
Evolutionary constraints on chaperone-mediated folding provide an antiviral approach refractory to development of drug resistance
Authors: Geller Ron , Vignuzzi Marco , Andino Raul , Frydman Judith
Published: January 2007

The genome diversity of RNA viruses allows for rapid adaptation to a wide variety of adverse conditions. Accordingly, viruses can escape inhibition by most antiviral compounds targeting either viral or host factors. Here we exploited the capacity of RNA viruses for rapid adaptation to explore the evolutionary constraints of chaperone-mediated protein folding. We hypothesized that inhibiting a host molecular chaperone required for folding of a viral protein would force the virus to evolve an alternate folding strategy. We identified the chaperone Hsp90 as an essential factor for folding and maturation of picornavirus capsid proteins. Pharmacological inhibition of Hsp90 impaired the replication of poliovirus, rhinovirus, and coxsackievirus in cell culture. Strikingly, anti-Hsp90 treatment did not yield drug-resistant viruses, suggesting that the complexity of capsid folding precludes the emergence of alternate folding pathways. These results reveal tight evolutionary constraints on chaperone-mediated protein folding, which may be exploited for viral inhibition in vivo. Indeed, Hsp90 inhibitors drastically reduced poliovirus replication in infected animals without the emergence of drug-resistant escape mutants. We propose that targeting folding of viral proteins may provide a general antiviral strategy that is refractory to development of drug resistance.
The t-complex-encoded guanine nucleotide exchange factor Fgd2 reveals that two opposing signaling pathways promote transmission ratio distortion in the mouse
Authors: Bauer Hermann , Véron Nathalie , Willert Jürgen , Herrmann Bernhard G.
Published: January 2007

Transmission ratio distortion (TRD), the preferential inheritance of the t haplotype from t/+ males, is caused by the cooperative effect of four t-complex distorters (Tcd1–4) and the single t-complex responder (Tcr) on sperm motility. Here we show that Fgd2, encoding a Rho guanine nucleotide exchange factor, maps to the Tcd2 region. The t allele of Fgd2 is overexpressed in testis compared with wild type. A loss-of-function allele of Fgd2 generated by gene targeting reduces the transmission ratio of the t haplotype th49, directly demonstrating the role of Fgd2 as Distorter. Fgd2 identifies a second Rho G protein signaling pathway promoting TRD.
In-situ high-pressure study of the ordered phase of ethyl propionate
Authors: Gajda Roman , Katrusiak Andrzej
Published: January 2007

Ethyl propionate, C5H10O2 (m.p. 199 K), has been in-situ pressure-frozen and its structure determined at 1.34, 1.98 and 2.45 GPa. The crystal structure of the new high-pressure phase (denoted β) is different from phase α obtained by lowering the temperature. The freezing pressure of ethyl propionate at 296 K is 1.03 GPa. The molecule assumes an extended chain s-trans–trans–trans conformation, only slightly distorted from planarity. The closest intermolecular contacts in both phases are formed between carbonyl O and methyl H atoms; however, the ethyl-group H atoms in phase β form no contacts shorter than 2.58 Å. A considerable molecular volume difference of 24.2 Å3 between phases α and β can be rationalized in terms of degrees of freedom of molecules arranged into closely packed structures: the three degrees of freedom allowed for rearrangements of molecules confined to planar sheets in phase α, but are not sufficient for obtaining a densely packed pattern.
Structures of incommensurate and commensurate composite crystals Na
x
CuO2 (x = 1.58, 1.6, 1.62)
Authors: van Smaalen Sander , Dinnebier Robert , Sofin Mikhail , Jansen Martin
Published: January 2007

Na
x
CuO2 (x ≃ 1.6) has been synthesized for different compositions x, resulting in both commensurate and incommensurate composite crystals. The crystal structures are reported for two incommensurate compounds (x = 1.58 and 1.62) determined by Rietveld refinements against X-ray powder diffraction data. The incommensurate compounds and commensurate Na8Cu5O10 (x = 1.6) are found to possess similar structures, with valence fluctuations of Cu2+/Cu3+ as the origin of the modulations of the CuO2 subsystems; the displacive modulations of Na being defined by the closest Na—O contacts between the subsystems. A comparison of the structure models obtained from single-crystal X-ray diffraction, synchrotron-radiation X-ray powder diffraction and X-ray powder diffraction with Cu Kα1 radiation indicates that single-crystal X-ray diffraction is by far the most accurate method, while powder diffraction with radiation from an X-ray tube provides the least accurate structure model.
Extended structures of polyiodide salts of transition metal macrocyclic complexes
Authors: Blake Alexander J. , Li Wan-Sheung , Lippolis Vito , Parsons Simon , Schröder Martin
Published: January 2007

The structures of five polyiodide salts, [Co([9]aneS3)2]I11 (1), [Ni([9]aneS3)2]I6 (2), [Ni([9]aneS3)2]I10 (3), [Pd([12]aneS4)]I6 (4) and [Pd([14]aneS4)]I10·MeCN (5), containing the template cations [Co([9]aneS3)2]3+, [Ni([9]aneS3)2]2+, [Pd([12]aneS4)]2+ and [Pd([14]aneS4)]2+ ([9]aneS3 = 1,4,7-trithiacyclononane, [12]aneS4 = 1,4,7,10-tetrathiacyclododecane, [14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane) exhibit a range of polyiodide and polyanionic framework structures. In (1) the charge on the CoIII cation is balanced by three I_3^- anions, which along with a neutral di-iodine molecule form I_{11}^{3-} rings in an extended structure comprising undulating chains of alternating I_{11}^{3-} rings and complex cations. In (2) the complex cation is linked to two tri-iodide anions by S...I interactions into well separated sheets of cations and anions, while in (3), I_5^- anions are linked by I...I interactions into helices which are cross-linked by S...I contacts to form sheets. Rather longer I...I contacts in (4) assemble I_3^- ions into 2 × 2 rods, which are linked into a three-dimensional network by S...I contacts. In (5) the N atom of the acetonitrile solvent molecule forms an array of four weak C—H...N hydrogen bonds to the macrocycle. The extended structure comprises corrugated zigzag chains of polyiodide rings formed by linked I_5^- units; the complex cations are attached to the polyiodide network by S...I contacts, which link the chains to form layers.
Multipole refinement and electron density analysis in natural borosilicate datolite using X-ray diffraction data
Authors: Ivanov Yu. V. , Belokoneva E. L.
Published: January 2007

The electron density distribution in the layer silicate datolite, Ca[BOH(SiO4)], was analyzed using high-precision single-crystal X-ray diffraction data (Mo Kα, T = 293 K). The Hansen–Coppens multipole model and Bader's topological analysis of the electron density provides a basis for the quantitative characterization of the bonded interaction of datolite. The results are presented both in the form of maps of the electron density distribution and its Laplacian, and in a compact way in terms of the critical points of the electron density. The relative electronegativities are also discussed. It was shown that closed-shell type interactions exist between Ca and O atoms, whereas Si—O and B—O bonds exhibit an intermediate nature with a strong covalent component. An analysis of the topology of the electrostatic potential demonstrates the relevance of considering this physical property to obtain a complete picture of structure-forming factors.
Low-temperature enantiotropic k2 phase transition in the ionic 222-cryptand complex with LiClO4
Authors: Guzei Ilia A. , Spencer Lara C. , Su Joe W. , Burnette Ronald R.
Published: January 2007

Crystallographic analyses at 100 and 200 K are reported for the macrobicyclic polyether 4,7,13,16,21,24-hexaoxa-1,10-diaza-bicyclo[8.8.8]hexacosane (denoted as 222-cryptand) that encapsulates a Li+ cation and then forms a complex (I) with ClO_4^-. Compound (I) undergoes a reversible second-order k phase transition at 253 (2) K from an almost ordered structure [space group P212121] at 100 K to a more disordered structure that exhibits a different unit cell [P21212 (2c′ = c)] above 253 (2) K. At 295 K the Li+ cation and five atoms of the perchlorate anion are each disordered over at least two positions about a crystallographic twofold axis [Chekhlov (2003). Russ. J. Coord. Chem.
29, 828–832]; as the temperature decreases the dynamic positional disorder is slowly frozen out, but is still observed for lithium even at 100 K. Based upon DFT computations, it seems that in the solid state the position of the Li+ cation in the cavity of the 222-cryptand below 253 (2) K likely corresponds to a local energy minimum; the global minimum in the gas phase corresponds to a near D
3 symmetrical conformation of the 222-cryptand with the undersized Li+ cation residing in the center of its cavity.
Analysis of structures with saturated hydrogen bonding
Authors: Loehlin James H. , Okasako Elizabeth L. N.
Published: January 2007

All simple structures with saturated hydrogen bonding (SHB) are classified into eight categories on the basis of the donor and acceptor numbers on the atoms at each end of the hydrogen bonds. Examples from the literature are included where known, along with seven structures investigated as part of this study (five have SHB). Graph-set descriptions of the hydrogen-bond patterns are given for each of these structures and for some selected literature examples. The structures presented are: piperazine (I), morpholinium chloride (II) and iodide (III) [(II) and (III) are not SHB], three 1:1 cocrystals of diols with 1,4-phenylenediamine (PDA) – PDA·1,8-octane diol (IV), PDA·1,10-decane diol (V), and PDA·1,12-dodecane diol (VI) and 6-amino-1-hexanol (VII). This study discusses some structures that show limitations of the graph-set model, along with possible suggestions to cover these limitations. The cocrystalline PDA·aliphatic diol structures may provide details applicable to the structure of self-assembled monolayers of aliphatic thiol molecules on Au(111) surfaces.
Ab initio constrained crystal-chemical Rietveld refinement of Ca10(V
x
P1 − x
O4)6F2 apatites
Authors: Mercier Patrick H. J. , Dong Zhili , Baikie Thomas , Le Page Yvon , White T. J. , Whitfield Pamela S. , Mitchel Lyndon D.
Published: January 2007

Extraction of reliable bond distances and angles for Ca10(V
x
P1 − x
O4)6F2 apatites using standard Rietveld refinement with Cu Kα X-ray powder data was significantly impaired by large imprecision for the O-atom coordinates. An initial attempt to apply crystal-chemical Rietveld refinements to the same compounds was partly successful, and exposed the problematic determination of two oxygen–metal–oxygen angles. Ab initio modeling with VASP in space groups P63/m, P21/m and Pm showed that both these angular parameters exhibited a linear dependence with the vanadium content. Stable crystal-chemical Rietveld refinements in agreement with quantum results were obtained by fixing these angles at the values from ab initio simulations. Residuals were comparable with the less precise standard refinements. The larger vanadium ion is accommodated primarily by uniform expansion and rotation of BO4 tetrahedra combined with a rotation of the Ca–Ca–Ca triangular units. It is proposed that the reduction of symmetry for the vanadium end-member is necessary to avoid considerable departures from formal valences at the A
II and B sites in P63/m. The complementarity of quantum methods and structural analysis by powder diffraction in cases with problematic least-squares extraction of the crystal chemistry is discussed.
Determination of covalent bond orders and atomic valence indices using topological features of the experimental electron density
Authors: Tsirelson Vladimir G. , Bartashevich Ekaterina V. , Stash Adam I. , Potemkin Vladimir A.
Published: January 2007

We present an approach for the determination of covalent bond orders from the experimental electron density and its derivatives at the bond critical points. An application of this method to a series of organic compounds has shown that it provides a bonding quantification that is in reasonable agreement with that obtained by orbital theory. The `experimental' atomic valence indices are also defined and their significance for the characterization of chemical problems is discussed.
Structure of the novel ternary hydrides Li4
Tt
2D (Tt = Si and Ge)
Authors: Wu Hui , Hartman Michael R. , Udovic Terrence J. , Rush John J. , Zhou Wei , Bowman Jr Robert C. , Vajo John J.
Published: January 2007

The crystal structures of newly discovered Li4Ge2D and Li4Si2D ternary phases were solved by direct methods using neutron powder diffraction data. Both structures can be described using a Cmmm orthorhombic cell with all hydrogen atoms occupying Li6-octahedral interstices. The overall crystal structure and the geometry of these interstices are compared with those of other related phases, and the stabilization of this novel class of ternary hydrides is discussed.
Temperature-dependent crystal structure refinement and 57Fe Mössbauer spectroscopy of Cu2Fe2Ge4O13
Authors: Redhammer Günther J. , Merz Michael , Tippelt Gerold , Sparta Karine , Roth Georg , Treutmann Werner , Lottermoser Werner , Amthauer Georg
Published: January 2007

The germanate compound Cu2Fe2Ge4O13, dicopper diiron germanate, was synthesized by solid-state reaction at 1403 K and ambient pressure. There is no change of space-group symmetry between 10 and 900 K. Between 40 K and room temperature the a lattice parameter shows a negative thermal expansion which can be connected to a decreasing Cu—Cu interatomic distance. Above room temperature all the lattice parameters are positively correlated with temperature. Among the structural parameters several alterations with temperature occur, which are most prominent for the distorted Fe3+ octahedral site. Besides an increase of the average bond length and of the interatomic Fe—Fe distances, distortional parameters also increase with temperature, while the average Cu—O bond length remains almost constant between 100 and 900 K, as do the average Ge—O distances. 57Fe Mössbauer spectroscopy was used to detect long-range magnetic ordering in Cu2Fe2Ge4O13. While around 100 K, which is the temperature at which a broad maximum is observed in the magnetic susceptibility, no magnetic ordering was detected in the Mössbauer spectrum, below 40 K a narrow split sextet is developed which is indicative of a three-dimensional magnetic ordering of the sample.
Cu3MgCl2(OH)6 and the bond-valence parameters of the OH—Cl bond
Authors: Malcherek Thomas , Schlüter Jochen
Published: January 2007

The title compound is a new mineral consisting of sheets made from edge-sharing Cu(OH)4Cl2 and Mg(OH)6 octahedra. The sheets are only weakly linked by O—H—Cl bridges, giving rise to perfect cleavage along (001) and to strong texture effects in powder diffraction measurements. Owing to low bond-valence sums at the Cl sites of Cu3MgCl2(OH)6 and of several related compounds, bond-valence parameters for the H/Cl pair have been refined to R
0 = 1.336 and b = 0.53 Å based on the crystal structures of selected hydroxychlorides.
Structures of mono-unsaturated triacylglycerols. II. The β2 polymorph. Corrigendum
Authors: van Mechelen Jan B. , Peschar Rene , Schenk Henk
Published: January 2007

A replacement Fig. 3 to the paper by van Mechelen et al. (2006), Acta Cryst. B62, 1131–1138 is given.
Specific expression of hepatocyte nuclear factor‐1β in the ovarian clear cell adenocarcinoma and its application to cytological diagnosis
Authors: Higashiguchi Atsushi , Yamada Taketo , Susumu Nobuyuki , Mori Taisuke , Suzuki Atsushi , Aoki Daisuke , Sakamoto Michiie
Published: January 2007

Ascitic cytological diagnosis is critical, but ovarian adenocarcinoma cells and reactive mesothelial cells can be difficult to distinguish because they usually have atypical cell nuclei and increased nuclear/cytoplasmic ratios. Previous studies using DNA microarrays have demonstrated that hepatocyte nuclear factor‐1β (HNF‐1β) is expressed specifically in clear cell adenocarcinoma (CCC). Thus, in the present study, we investigated the usefulness of HNF‐1β as an immunocytochemical diagnostic marker of CCC in ascitic specimens. We first confirmed that HNF‐1β expression levels were significantly higher in CCC than in non‐CCC (i.e. serous adenocarcinoma, mucinous adenocarcinoma and endometrioid adenocarcinoma) in 55 surgical specimens at both the mRNA (P < 0.05) and protein (P < 0.05) levels by real‐time polymerase chain reaction and immunohistochemistry, respectively. Immunocytochemistry of 60 cytological specimens showed significant positivity in CCC cases whereas all non‐CCC cells, except for three endometrioid adenocaricnoma cases, and mesothelial cells in the background stained negatively for anti‐HNF‐1β antibody (P < 0.05). The sensitivity and specificity were calculated to be 0.955 and 0.921, respectively. Immmunostaining patterns of HNF‐1β on cytological specimens were similar to those observed on histopathological ovarian specimens from the same patients. Double immunohistochemical staining using anti‐HNF‐1β antibody and HBME‐1, a mesothelium‐specific monoclonal antibody, confirmed that anti‐HNF‐1β antibody distinguished CCC cells and mesothelial cells. In conclusion, our findings indicate the specific expression of HNF‐1β in ovarian CCC and possible clinical applications of HNF‐1β immunocytochemical staining for the differential cytopathological diagnosis of CCC from non‐CCC, as well as from mesothelial cells using cytological specimens from ovarian carcinoma patients. (Cancer Sci 2007; 98: 387–391)
Technetium‐99m sestamibi scintigraphy is sensitive and specific for the staging and the follow‐up of patients with multiple myeloma: a multicentre study on 397 scans
Authors: Mele Anna , Offidani Massimo , Visani Giuseppe , Marconi Monica , Cambioli Filippo , Nonni Marco , Catarini Massimo , Brianzoni Ernesto , Berbellini Alfonso , Ascoli Giorgio , Brunori Marino , Agostini Vanessa , Corvatta Laura , Isidori Alessandro , Spinelli Aureliano , Gradari Marinella , Leoni Pietro
Published: January 2007

We evaluated the additional benefit of Technetium99‐sestamibi (99mTc‐MIBI) scanning in comparison with standard X‐ray techniques for multiple myeloma patients either at diagnosis or during follow‐up. Between February 2001 and January 2005, 397 whole body scans were acquired. On 229 scans performed at diagnosis, 146 (64%) were positive and 81 cases have discordant X‐ray results. The sensitivity of 99mTc‐MIBI and X‐ray were 77% and 45% respectively. As a result of 99mTc‐MIBI, 40% of asymptomatic myeloma patients were up‐staged. The positivity of 99mTc‐MIBI correlated significantly with all of the most relevant clinical and biological parameters. Multivariate analysis selected only high reactive C protein (P = 0·0005), bone marrow infiltration (P = 0·02) and bone pain (P = 0·002) as factors affecting 99mTc‐MIBI pattern. In 22 patients with solitary myeloma, 99mTc‐MIBI was positive in 86% of cases and detected more disease sites than X‐ray. Among 168 scans performed during follow‐up, 99mTc‐MIBI presented high specificity in patients showing a complete response (CR; 86%), and correlated with myeloma activity and with response to therapy. At multivariate analysis, a positive pattern correlated with bone marrow infiltration (P = 0·002) and disease status other than CR (P = 0·03). We conclude that 99mTc‐MIBI scanning is an additional diagnostic tool with a high specificity for the staging and the follow‐up of multiple myeloma patients.
Tracking palustrine water seasonal and annual variability in agricultural wetland landscapes using Landsat from 1997 to 2005
Authors: BEERI OFER , PHILLIPS REBECCA L.
Published: January 2007

Wetlands densely populate the ecoregion transecting the center of the Prairie Pothole Region (PPR) known as the Missouri Coteau and epicenter to the most productive waterfowl‐breeding habitat in North America. These palustrine, depressional basin waters vacillate with regional drought and deluge, so surface water fluctuations over time modulate wetland productivity, habitat, and water quality functions. Models predict formidable effects of climate change on glacial basin surface waters, yet large‐scale, long‐term observation data are lacking to compare against predicted changes. Current, optical‐based water detection models do not delineate marsh vegetation from shallow, turbid, high‐chlorophyll waters common to the region. We developed a palustrine wetland spectral model for tracking open surface waters using Landsat imagery, which we evaluated for a 2500 km2 landscape that estimates seasonal and annual open water variability for thousands of individual wetlands in the Missouri Coteau ecoregion. Detection accuracy of 96% was achieved for water bodies greater than a half‐pixel in size. We identified shifts in the distribution of water permanence classes within and between years for waters emerging in spring, mid‐summer, and late summer from 1997 to 2005 and identified a maximum of 19 047 basins with open water (12% of the landscape) populating 2500 km2. For the 2005 growing season, we observed only 8757 basins with open water (6% of the landscape) for the same area. Declines were greatest for water bodies detected only in spring, suggesting a loss of those wetlands functioning to recharge groundwater stores early in the season and a high sensitivity to observed reductions in snowfall. If landscape factors driving open water coverage and wetland density are similar for the entire Missouri Coteau, we estimate the number of basins containing at least a pixel of water for this region declined from 577 600 to 266 000 between 1997 and 2005.
Does structured clinical supervision during psychosocial intervention education enhance outcome for mental health nurses and the service users they work with?
Authors: BRADSHAW T. , BUTTERWORTH A. , MAIRS H.
Published: January 2007

This study aimed to assess whether clinical supervision provided by workplace‐based supervisors can enhance outcomes for mental health nurses attending a psychosocial intervention education programme and the service users whom they work with. A quasi‐experimental controlled design was used. The main outcome measure was student knowledge and attitudes towards individuals with psychosis and their caregivers. Secondary outcome measures for service users included the KGV (M) symptom scale and the Social Functioning Scale. Students in the experimental group demonstrated a significant increase in knowledge of psychological interventions compared with the control group. Service users seen by the students in the experimental group showed significantly greater reductions in positive psychotic symptoms and total symptoms compared with those seen by students in the control group. Workplace clinical supervision may offer additional benefit to nurses attending psychosocial intervention courses. Further research adopting more robust designs is required to support these tentative findings.
Consumer input into standards revision: changing practice
Authors: BEAL G. , CHAN A. , CHAPMAN S. , EDGAR J. , MCINNIS‐PERRY G. , OSBORNE M. , MINA E. S.
Published: January 2007

As part of ongoing quality improvement initiatives, the Canadian Standards for Psychiatric‐Mental Health Nursing were recently revised. For the first time since the standards were published in 1995, the input of consumers of mental health services was sought. Thirty‐one consumers from across Canada participated in focus groups, and answered questions related to the domains of practice as identified in the standards document. Through this input, consumers were able to inform the committee regarding areas of satisfaction and dissatisfaction from their unique perspective. Through this article, the process of consumer collaboration is illustrated in relation to how it shaped Standards revision, and finally how it affected the practitioners involved.
To correct and to acknowledge: two simultaneous and conflicting perspectives of limit‐setting in mental health nursing
Authors: VATNE S. , FAGERMOEN M. S.
Published: January 2007

This article reports about a study of nurses’ limit‐setting in mental health and the rationality behind correcting and therapeutic limit‐setting interventions. Based on action science design, the study comprised three phases; namely a descriptive, reflective and concluding phase. Qualitative data were collected from various data sources; namely participant observations, interviews and written narratives. Eleven nurses participated. The main findings relate nurses’ limit‐setting interventions to two simultaneous and conflicting perspectives. That is:

• The dominating perspective of correcting, aimed at changing patients’ behaviour by external control through three nursing roles of caregiver, educator and gatekeeper.

• The weaker perspective of acknowledging, where patients are seen as capable of changing themselves from within. The nurse’s role reflects compassion and values patients’ integrity.

The nurses’ work was based on a rationality of coping, because of a balancing act between the two perspectives and conflicting intrapersonal feelings aroused in challenging encounters with patients and colleagues. In reflection groups, relational interventions were developed, grounded in wondering reflection. Patients were regarded as participants in an open dialogue with the aim of securing collaboration.