bluuebunny/crossref_metadata_2025 huggingface dataset:
Scanning probe acceleration microscopy (SPAM) in fluids: Mapping mechanical properties of surfaces at the nanoscale
Authors: Legleiter Justin , Park Matthew , Cusick Brian , Kowalewski Tomasz
Published: March 2006

One of the major thrusts in proximal probe techniques is combination of imaging capabilities with simultaneous measurements of physical properties. In tapping mode atomic force microscopy (TMAFM), the most straightforward way to accomplish this goal is to reconstruct the time-resolved force interaction between the tip and surface. These tip–sample forces can be used to detect interactions (e.g., binding sites) and map material properties with nanoscale spatial resolution. Here, we describe a previously unreported approach, which we refer to as scanning probe acceleration microscopy (SPAM), in which the TMAFM cantilever acts as an accelerometer to extract tip–sample forces during imaging. This method utilizes the second derivative of the deflection signal to recover the tip acceleration trajectory. The challenge in such an approach is that with real, noisy data, the second derivative of the signal is strongly dominated by the noise. This problem is solved by taking advantage of the fact that most of the information about the deflection trajectory is contained in the higher harmonics, making it possible to filter the signal by “comb” filtering, i.e., by taking its Fourier transform and inverting it while selectively retaining only the intensities at integer harmonic frequencies. Such a comb filtering method works particularly well in fluid TMAFM because of the highly distorted character of the deflection signal. Numerical simulations and
in situ
TMAFM experiments on supported lipid bilayer patches on mica are reported to demonstrate the validity of this approach.
The Strong Anick Conjecture
Authors: Drensky Vesselin , Yu Jie-Tai
Published: March 2006

Recently, Umirbaev proved the long-standing Anick conjecture, that is, there exist wild automorphisms of the free associative algebra
K〈x, y, z〉
over a field
K
of characteristic 0. In particular, the well known Anick automorphism is wild. In this work, we obtain a stronger result (the Strong Anick Conjecture that implies the Anick Conjecture). Namely, we prove that there exist wild coordinates of
K〈x, y, z〉
. In particular, the two nontrivial coordinates in the Anick automorphism are both wild. We establish a similar result for several large classes of automorphisms of
K〈x, y, z〉
. We also discover a large, previously undescribed class of wild automorphisms of
K〈x, y, z〉
that is not covered by the results of Umirbaev.
Role of DNA bubble rewinding in enzymatic transcription termination
Authors: Park Joo-Seop , Roberts Jeffrey W.
Published: March 2006

By using DNA heteroduplexes that inhibit rewinding of the upstream part of the transcription bubble, we show that transcript release in termination by the enzymes Mfd and Rho is facilitated by reannealing of DNA in the upstream region of the transcription bubble, as is also true for termination by intrinsic terminators. We also show that, like Mfd, the Rho termination factor promotes forward translocation of RNA polymerase. These results support termination models in which external forces imposed on nucleic acids induce concerted rewinding of DNA and unwinding of the DNA/RNA hybrid, possibly accompanied by forward translocation of RNA polymerase, leading to transcription complex dissociation.
Carbon monoxide rescues ischemic lungs by interrupting MAPK-driven expression of early growth response 1 gene and its downstream target genes
Authors: Mishra Snigdha , Fujita Tomoyuki , Lama Vibha N. , Nam Douglas , Liao Hui , Okada Morihito , Minamoto Kanji , Yoshikawa Yasushi , Harada Hiroaki , Pinsky David J.
Published: March 2006

Carbon monoxide (CO), an endogenous cytoprotective product of heme oxygenase type-1 regulates target thrombotic and inflammatory genes in ischemic stress. Regulation of the gene encoding early growth response 1 (Egr-1), a potent transcriptional activator of deleterious thrombotic and inflammatory cascades, may govern CO-mediated ischemic lung protection. The exact signaling mechanisms underlying CO-mediated cytoprotection are not well understood. In this study we tested the hypothesis that inhibition of mitogen-activated protein kinase-dependent Egr-1 expression may be pivotal in CO-mediated ischemic protection. In anin vivoisogeneic rat lung ischemic injury model, inhaled CO not only diminished fibrin accumulation and leukostasis and improved gas exchange and survival but also suppressed extracellular signal-regulated kinase (ERK) activation, Egr-1 expression, and Erg DNA-binding activity in lung tissue. Additionally, CO-mediated inhibition of Egr-1 reduced expression of target genes, such as tissue factor, serpine-1, interleukin-1, and TNF-α. However, CO failed to inhibit serpine-1 expression after unilateral lung ischemia in mice null for theEgr-1gene. In RAW macrophagesin vitro, hypoxia-induced Egr-1 mRNA expression was ERK-dependent, and CO-mediated suppression of ERK activation resulted in Egr-1 inhibition. Furthermore, CO suppression of ERK phosphorylation was reversed by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one but was insensitive to cAMP-dependent protein kinase A inhibition with H89 and NO synthase inhibition withl-nitroarginine methyl ester. This finding indicates that CO suppresses ERK in a cGMP-dependent but cAMP/protein kinase A- and NO-independent manner. Together, these data identify a unifying molecular mechanism by which CO interrupts proinflammatory and prothrombotic mediators of ischemic injury.
Lusztig’s conjecture for finite special linear groups
Authors: Shoji Toshiaki
Published: March 2006

In this paper, we prove Lusztig’s conjecture forGF=SLn(Fq)G^F = SL_n(\mathbf F_q), i.e., we show that characteristic functions of character sheaves ofGFG^Fcoincide with almost characters ofGFG^Fup to scalar constants, assuming that the characteristic ofFq\mathbf F_qis not too small. We determine these scalars explicitly. Our result gives a method of computing irreducible characters ofGFG^F.
Expansion complexes for finite subdivision rules. I
Authors: Cannon J. , Floyd W. , Parry W.
Published: March 2006

This paper develops the basic theory of conformal structures on finite subdivision rules. The work depends heavily on the use of expansion complexes, which are defined and discussed in detail. It is proved that a finite subdivision rule with bounded valence and mesh approaching

0
0

is conformal (in the combinatorial sense) if there is a partial conformal structure on the model subdivision complex with respect to which the subdivision map is conformal. This gives a new approach to the difficult combinatorial problem of determining when a finite subdivision rule is conformal.
BicAT: a biclustering analysis toolbox
Authors: Barkow Simon , Bleuler Stefan , Prelić Amela , Zimmermann Philip , Zitzler Eckart
Published: March 2006

Summary: Besides classical clustering methods such as hierarchical clustering, in recent years biclustering has become a popular approach to analyze biological data sets, e.g. gene expression data. The Biclustering Analysis Toolbox (BicAT) is a software platform for clustering-based data analysis that integrates various biclustering and clustering techniques in terms of a common graphical user interface. Furthermore, BicAT provides different facilities for data preparation, inspection and postprocessing such as discretization, filtering of biclusters according to specific criteria or gene pair analysis for constructing gene interconnection graphs. The possibility to use different biclustering algorithms inside a single graphical tool allows the user to compare clustering results and choose the algorithm that best fits a specific biological scenario. The toolbox is described in the context of gene expression analysis, but is also applicable to other types of data, e.g. data from proteomics or synthetic lethal experiments.

Availability: The BicAT toolbox is freely available at and runs on all operating systems. The Java source code of the program and a developer's guide is provided on the website as well. Therefore, users may modify the program and add further algorithms or extensions.

Contact:  barkow@tik.ee.ethz.ch
XQTav: an XQuery processor for Taverna environment
Authors: Sroka Jacek , Kaczor Grzegorz , Tyszkiewicz Jerzy , Kierzek Andrzej M.
Published: March 2006

Taverna workbench is an environment for construction, visualization and execution of bioinformatic workflows that integrate specialized tools available through the internet. It is gaining popularity fast, because of supporting the most important bioinformatic services and its simple, yet robust graphical notation. Here we present XQTav—an extension of Taverna that provides full integration with XQuery (the query language for XML) engine. XQTav allows execution of XQuery scripts in Taverna workflow diagrams. All existing Taverna processors can be accessed in the XQuery scripts. This provides an alternative way of specifying subworkflows in Taverna and is useful when one deals with query-like algorithms (e.g. filters and inner joins). Moreover, XQtav may be used to automatically generate an XQuery script that is equivalent to Taverna's workflow. This constitutes another way of creating and enacting bioinformatic workflows: overall structure of a diagram is drawn in Taverna environment, XQuery code is generated and possibly adjusted by hand. It can be executed by XQuery engines or incorporated into other software environments.

Availability: XQtav is an open source software. It may be downloaded from . The page also contains various tutorials and examples, including the one described in this report.

Contact:  sroka@mimuw.edu.pl, a.kierzek@surrey.ac.uk
Phylogeny-independent detection of functional residues
Authors: Pazos Florencio , Rausell Antonio , Valencia Alfonso
Published: March 2006

Motivation: Current projects for the massive characterization of proteomes are generating protein sequences and structures with unknown function. The difficulty of experimentally determining functionally important sites calls for the development of computational methods. The first techniques, based on the search for fully conserved positions in multiple sequence alignments (MSAs), were followed by methods for locating family-dependent conserved positions. These rely on the functional classification implicit in the alignment for locating these positions related with functional specificity. The next obvious step, still scarcely explored, is to detect these positions using a functional classification different from the one implicit in the sequence relationships between the proteins. Here, we present two new methods for locating functional positions which can incorporate an arbitrary external functional classification which may or may not coincide with the one implicit in the MSA. The Xdet method is able to use a functional classification with an associated hierarchy or similarity between functions to locate positions related to that classification. The MCdet method uses multivariate statistical analysis to locate positions responsible for each one of the functions within a multifunctional family.

Results: We applied the methods to different cases, illustrating scenarios where there is a disagreement between the functional and the phylogenetic relationships, and demonstrated their usefulness for the phylogeny-independent prediction of functional positions.

Availability: All computer programs and datasets used in this work are available from the authors for academic use.

Contact:  pazos@cnb.uam.es

Supplementary information: Supplementary data are available at
UniSave: the UniProtKB Sequence/Annotation Version database
Authors: Leinonen Rasko , Nardone Francesco , Zhu Weimin , Apweiler Rolf
Published: March 2006

Summary: The UniProtKB Sequence/Annotation Version database (UniSave) is a comprehensive archive of UniProtKB/Swiss-Prot and UniProtKB/TrEMBL entry versions. All changed Swiss-Prot and TrEMBL entries are loaded into the UniSave as part of the public bi-weekly UniProtKB releases. Unlike the UniProtKB, which contains only the latest Swiss-Prot and TrEMBL entry versions, the UniSave provides access to previous versions of these entries.

Availability:  

Contact:  rolf.apweiler@ebi.ac.uk
Identifying gene expression changes in breast cancer that distinguish early and late relapse among uncured patients
Authors: Broët Philippe , Kuznetsov Vladimir A. , Bergh Jonas , Liu Edison T. , Miller Lance D.
Published: March 2006

Motivation: In recent years, microarray technology has revealed many tumor-expressed genes prognostic of clinical outcomes in early-stage breast cancer patients. However, in the presence of cured patients, evaluating gene effect on time to relapse is quite complex since it may affect either the probability of never experiencing a relapse (cure effect) or the time to relapse among the uncured patients (disease progression effect) or both. In this context, we propose a simple and an efficient method for identifying gene expression changes that characterize early and late recurrence for uncured patients.

Results: Simulation results show the good performance of the proposed statistic for detecting a disease progression effect. In a study of early-stage breast cancer, our results show that the proposed statistic provides a more powerful basis for gene selection than the classical Cox model-based statistic. From a biological perspective, many of the genes identified here as associated with the speed of disease recurrence have known roles in tumorigenesis.

Contact:  broet@vjf.inserm.fr; kuznetsov@gis.a-star.edu.sg
Description of Ba1 + x
Ni
x
Rh1 − x
O3 with x = 0.1170 (5) in superspace: modulated composite versus modulated-layer structure
Authors: Schönleber Andreas , Zúñiga F. Javier , Perez-Mato J. Manuel , Darriet Jacques , zur Loye Hans-Conrad
Published: March 2006

The structure of the compound Ba1 + x
Ni
x
Rh1 − x
O3 [x = 0.1170 (5)] has been analyzed at room temperature within the (3 + 1)-dimensional superspace approach using single-crystal X-ray diffraction data. Two different models are presented, the compound is refined as modulated composite as well as modulated-layer structure. In both models discontinuous atomic domains are applied to describe the structural modulations. While the first approach stresses the pseudo-one-dimensional constitution, the latter highlights the layered character of these structures.
Solvothermal synthesis, multi-temperature crystal structures and physical properties of isostructural coordination polymers, 2C4H12N+[M
3(C8H4O4)4]2−·3C5H11NO, M = Co, Zn
Authors: Damgaard Poulsen Rasmus , Bentien Anders , Christensen Mogens , Brummerstedt Iversen Bo
Published: March 2006

Two isostructural metal organic framework (MOF) structures have been synthesized by solvothermal methods and examined by single-crystal X-ray diffraction. A microcrystal of 2C4H12N+[Co3(C8H4O4)4]2−·3C5H11NO (1) was investigated at T = 120 K using synchrotron radiation. 2C4H12N+[Zn3(C8H4O4)4]2−·3C5H11NO (2) was investigated at multiple temperatures (T = 30, 100, 200 and 300 K) on a conventional diffractometer. The thermal expansion of the structure of (2) is anisotropic and along the a axis, which corresponds to the metal chain direction. The structures contain anionic frameworks with cations and solvent molecules trapped in the voids. The magnetic susceptibility (χ) and heat capacity (C

p
) have been measured from 1.8 to 350 K. Compound (1) orders ferromagnetically with a broad phase transition observed in C

p
at ∼ 6 K. The magnetic moment reaches a value of 3 µB per Co at 2 K in a magnetic field of 9 T, and a Curie–Weiss fit to χ(T) gives an effective moment (μ
eff) of 4.2 μ
B and a Weiss temperature (θ) of 23 K. The exchange mechanism for the magnetic coupling is suggested to involve the Co—O—Co bridges in the individual three-metal-atom subchains. The three-dimensional magnetism presumably is due to super-exchange through two out of the three unique C8H4O4 linker molecules, which have the carboxylate and benzene π systems well aligned.
Low-temperature structure of rubrene single crystals grown by vapor transport
Authors: Jurchescu Oana D. , Meetsma Auke , Palstra Thomas T. M.
Published: March 2006

We report the crystal structure of rubrene, C42H28 (5,6,11,12-tetraphenyltetracene), in the temperature interval 100–300 K. The crystals are grown by physical vapor transport in an open system. The crystal structure is orthorhombic over the entire temperature range.
Crystal structure of the high-pressure phase of the oxonitridosilicate chloride Ce4[Si4O3 + x
N7 − x
]Cl1 − x
O
x
, x ≃ 0.2
Authors: Friedrich Alexandra , Haussühl Eiken , Morgenroth Wolfgang , Lieb Alexandra , Winkler Björn , Knorr Karsten , Schnick Wolfgang
Published: March 2006

The structural compression mechanism of Ce4[Si4O3 + x
N7 − x
]Cl1 − x
O
x
, x ≃ 0.2, was investigated by in situ single-crystal synchrotron X-ray diffraction at pressures of 3.0, 8.5 and 8.6 GPa using the diamond–anvil cell technique. On increasing pressure the low-pressure cubic structure first undergoes only minor structural changes. Between 8.5 and 8.6 GPa a first-order phase transition occurs, accompanied by a change of the single-crystal colour from light orange to dark red. The main structural mechanisms, leading to a volume reduction of about 5% at the phase transition, are an increase in and a rearrangement of the Ce coordination, the loss of the Ce2, Ce3 split position, and a bending of some of the inter-polyhedral Si—N—Si angles in the arrangement of the corner-sharing Si tetrahedra. The latter is responsible for the short c axis of the orthorhombic high-pressure structure compared with the cell parameter of the cubic low-pressure structure.
Structure of Ce2RhIn8: an example of complementary use of high-resolution neutron powder diffraction and reciprocal-space mapping to study complex materials
Authors: Moshopoulou E. G. , Ibberson R. M. , Sarrao J. L. , Thompson J. D. , Fisk Z.
Published: March 2006

The room-temperature crystal structure of the heavy fermion antiferromagnet Ce2RhIn8, dicerium rhodium octaindide, has been studied by a combination of high-resolution synchrotron X-ray reciprocal-space mapping of single crystals and high-resolution time-of-flight neutron powder diffraction. The structure is disordered, exhibiting a complex interplay of non-periodic, partially correlated planar defects, coexistence and segregation of polytypic phases (induced by periodic planar `defects'), mosaicity (i.e. domain misalignment) and non-uniform strain. These effects evolve as a function of temperature in a complicated way, but they remain down to low temperatures. The room-temperature diffraction data are best represented by a complex mixture of two polytypic phases, which are affected by non-periodic, partially correlated planar defects, differ slightly in their tetragonal structures, and exhibit different mosaicities and strain values. Therefore, Ce2RhIn8 approaches the paracrystalline state, rather than the classic crystalline state and thus several of the concepts of conventional single-crystal crystallography are inapplicable. The structural results are discussed in the context of the role of disorder in the heavy-fermion state and in the interplay between superconductivity and magnetism.
On the crystal structure of Cr2N precipitates in high-nitrogen austenitic stainless steel. II. Order–disorder transition of Cr2N during electron irradiation
Authors: Lee Tae-Ho , Kim Sung-Joon , Takaki Setsuo
Published: March 2006

The crystal structure and order–disorder transition of Cr2N were investigated utilizing transmission electron microscopy (TEM). Based on the analyses of selected-area diffraction (SAD) patterns, the crystal structure of the ordered Cr2N superstructure was confirmed to be trigonal (P\overline 3 1m), characterized by three sets of superlattice reflections (001), (1\over 31\over 30) and (1\over 31\over 31). During electron irradiation, the superlattice reflections gradually disappeared in the regular sequence (001), (1\over 31\over 30) and (1\over 31\over 31), indicating that the order–disorder phase transition of Cr2N occurred. The convergent-beam electron diffraction (CBED) observation revealed that the space group of disordered Cr2N is P63/mmc, which corresponds to an h.c.p. (hexagonal close packed) sublattice of metal atoms with a random distribution of N atoms in six octahedral interstices. The redistribution model of N atoms through the order–disorder transition is discussed based on the characteristics and disappearing sequence of superlattice reflections.
AtMBD9: a protein with a methyl‐CpG‐binding domain regulates flowering time and shoot branching in Arabidopsis
Authors: Peng Mingsheng , Cui Yuhai , Bi Yong‐Mei , Rothstein Steven J.
Published: March 2006

The functional characterization of mammalian proteins containing a methyl‐CpG‐binding domain (MBD) has revealed that MBD proteins can decipher the epigenetic information encoded by DNA methylation, and integrate DNA methylation, modification of chromatin structure and repression of gene expression. The Arabidopsis genome has 13 putative genes encoding MBD proteins, and no specific biological function has been defined for any AtMBD genes. In this study, we identified three T‐DNA insertion mutant alleles at the AtMBD9 locus, and found that all of them exhibited obvious developmental abnormalities. First, the atmbd9 mutants flowered significantly earlier than wild‐type plants. The expression of FLOWERING LOCUS C (FLC), a major repressor of Arabidopsis flowering, was markedly attenuated by the AtMBD9 mutations. This FLC transcription reduction was associated with a significant decrease in the acetylation level in histone H3 and H4 of FLC chromatin in the atmbd9 mutants. Secondly, the atmbd9 mutants produced more shoot branches by increasing the outgrowth of axillary buds when compared with wild‐type plants. The two known major factors controlling the outgrowth of axillary buds in Arabidopsis, auxin and the more axillary growth (MAX) pathway, were found not to be involved in producing this enhanced shoot branching phenotype in atmbd9 mutants, indicating that AtMBD9 may regulate a novel pathway to control shoot branching. This pathway is not related to FLC expression as over‐expression of FLC in atmbd9‐2 restored its flowering time to one similar to that of the wild type, but did not alter the shoot branching phenotype.
A mutation in the uvi4 gene promotes progression of endo‐reduplication and confers increased tolerance towards ultraviolet B light
Authors: Hase Yoshihiro , Trung Khuat Huu , Matsunaga Tsukasa , Tanaka Atsushi
Published: March 2006

We have isolated and characterized a new ultraviolet B (UV‐B)‐resistant mutant, uvi4 (UV‐B‐insensitive 4), of Arabidopsis. The fresh weight (FW) of uvi4 plants grown under supplemental UV‐B light was more than twice that of the wild‐type. No significant difference was found in their ability to repair the UV‐B‐induced cyclobutane pyrimidine dimers, or in the amount of UV‐B absorptive compounds, both of which are well‐known factors that contribute to UV sensitivity. Positional cloning revealed that the UVI4 gene encodes a novel basic protein of unknown function. We found that the hypocotyl cells in uvi4 undergo one extra round of endo‐reduplication. The uvi4 mutation also promoted the progression of endo‐reduplication during leaf development. The UVI4 gene is expressed mainly in actively dividing cells. In the leaves of PUVI4::GUS plants, the GUS signal disappeared in basipetal fashion as the leaf developed. The total leaf blade area was not different between uvi4 and the wild‐type through leaf development, while the average cell area in the adaxial epidermis was considerably larger in uvi4, suggesting that the uvi4 leaves have fewer but larger epidermal cells. These results suggest that UVI4 is necessary for the maintenance of the mitotic state, and the loss of UVI4 function stimulated endo‐reduplication. Tetraploid Arabidopsis was hyper‐resistant to UV‐B compared to diploid Arabidopsis, suggesting that the enhanced polyploidization is responsible for the increased UV‐B tolerance of the uvi4 mutant.
Colorectal cancer – a prospective evaluation of symptom duration and GP referral patterns in an inner city teaching hospital
Authors: Khattak I. , Eardley N. J. , Rooney P. S.
Published: March 2006

Objective  A high percentage of colorectal cancer patients (CRC) present as an emergency. Our aim was to evaluate delays in referral based on patient and general practitioner (GP) factors to see if there was any difference between elective and emergency patients.

Method  Symptom questionnaires were prospectively collected from 101 consecutive patients presenting to a single colorectal unit (58 male, 43 female; median age 72 years) and entered into a database. Questionnaires assessed time from symptom onset until first GP visit, time for GP to refer, and type of admission. Symptoms and Dukes stage were noted.

Results  Fifty‐eight (57%) patients presented electively and 43 (43%) as an emergency. Eighty‐eight patients (87%) saw their GP of which 34 (39%) later presented as emergency; 13 (13%) did not see their GP. The median time before patients first sought medical advice was 30 days (0–1095 days). Median delay until treatment was 90 days (range 0–1460 days). Emergency patients waited a median of 11.5 days before visiting the GP, and elective a median of 49.5 days (P = 0.04) (Mann–Whitney U). Nine of 13 patients who did not see their GP presented as an emergency (median wait 44 days). The median time taken for a GP to refer to a hospital specialist was 28 days in elective patients and 14 days in the emergency group. (P = ns) Thirty (38%) patients took longer than six weeks to be referred (33% as an emergency). Thirty‐six patients had Dukes A or B and took a median of 30 days to first presentation. Sixty‐five had Dukes C or D and took a median of 32 days to first presentation. (P = ns)

Conclusion  Emergency patients have symptoms for less time before seeking medical advice compared to elective patients. The duration of these symptoms is unrelated to the histological stage at diagnosis. Although the majority of GPs referred CRC patients within six weeks, there was no association between time taken to refer and mode of presentation. The factors that relate to disease stage occur before symptoms are acted on.
Nurse led flexible sigmoidoscopy in primary care – the first thousand patients
Authors: Maruthachalam K. , Stoker E. , Nicholson G. , Horgan A. F.
Published: March 2006

Objectives  Secondary care Trusts have traditionally been providers of flexible sigmoidoscopy services in the United Kingdom. The aim of this study was to establish a Nurse‐led flexible sigmoidoscopy clinic that would provide a patient orientated service in a primary care setting.

Patients and methods  A protocol driven flexible sigmoidoscopy clinic was established in a primary care setting. The first thousand patients who underwent flexible sigmoidoscopy at the community clinic were prospectively studied.

Results  A nurse endoscopist performed 1002 procedures on 1000 patients. Median time from referral to flexible sigmoidoscopy was 35 days (Range 1–180 days). Two hundred and twenty‐two (22%) patients were diagnosed with significant colonic pathology including 25 (2.5%) patients with colorectal cancer. Median time from referral to histological diagnosis of colorectal cancer was 26 days (range 7–87 days). No complications were encountered. Patients who required further follow‐up were referred to a Consultant led (29%) or Nurse led clinic (5%) in secondary care. Patient satisfaction as assessed by postal questionnaire indicated that 447 (99%) patients were satisfied with the service.

Conclusions  A community endoscopy clinic can provide a safe and effective flexible sigmoidoscopy service with high levels of patient satisfaction. Nurse Endoscopists can extend their role in primary care with adequate training and support from secondary care hospitals.
Work factors as predictors of persistent fatigue: a prospective study of nurses’ aides
Authors: Eriksen W
Published: March 2006

Objectives:To identify work factors that predict persistent fatigue in nurses’ aides.

Methods:The sample comprised 5547 Norwegian nurses’ aides, not on leave when they completed a mailed questionnaire in 1999. Of these, 4645 (83.7%) completed a second questionnaire 15 months later. The outcome measure was the occurrence of persistent fatigue, defined as having felt “usually fatigued” or “always fatigued” in daytime during the previous 14 days.

Results:In respondents without persistent fatigue at baseline, medium and high work demands, heavy smoking, being single, and having long term health problems were associated with increased risk of persistent fatigue at follow up. Medium and high rewards for well done work, medium levels of leadership fairness, and regular physical exercise were associated with reduced risk of persistent fatigue at follow up. In respondents with persistent fatigue at baseline, medium and high levels of positive challenges at work, high support from immediate superior, medium feedback about quality of one’s work, and changes of work or work tasks that resulted in less heavy work or lower work pace were associated with increased odds of recovery (no persistent fatigue at follow up). Working in a nursing home and being intensely bothered by long term health problems were associated with reduced odds of recovery.

Conclusions:High demands and lack of rewards at work may cause persistent fatigue in nurses’ aides. Reduction of demands, adequate feedback, and mental stimulation in the form of support and positive challenges may facilitate recovery in those who have persistent fatigue. Leaders in the health services may be in a position to regulate factors that influence the level of fatigue in nurses’ aides.
Does enhanced information exchange between social insurance physicians and occupational physicians improve patient work resumption? A controlled intervention study
Authors: Mortelmans A K , Donceel P , Lahaye D , Bulterys S
Published: March 2006

Background:Patient work resumption after sickness absence varies even among patients with similar pathologies and characteristics. Explanations remain uncertain. One newly investigated field is “information asymmetry”, a situation in which critical information is not appropriately exchanged between stakeholders in disability management. It is hypothesised that information asymmetry between social insurance physicians and occupational physicians prolongs sickness absence.

Objectives:To assess the influence of enhanced information exchange between these physicians on patient outcome.

Methods:Non-randomised controlled intervention study. The setting was the work inability assessment consultation of social insurance physicians in Belgium. Inclusion criteria were: employee, age 18–50, and subacute (more than one month) sickness absence. The intervention was a structured information exchange (through the use of a communication form) between the patient’s social insurance physician and occupational physician. The intervention started when the patient’s sickness absence reached the subacute stage, and ended when the sickness absence benefit was ceased or the duration exceeded one year. The primary outcome measure was the sickness absence benefit status of the patient assessed one year after benefit onset.

Results:Of the 1883 patients asked to enrol in the study, 1564 (84%) participated; 505 (32%) of 1564 patients were assigned to the intervention group and 1059 (68%) to the control group; 1553 (99%) of 1564 patients completed the study. In the intervention group, 86% received no sickness absence benefit at the end of the study, versus 84% in the control group (95% CI 0.91–1.15). No significant differences in other outcome parameters were obtained.

Conclusions:Information exchange between physicians may not be enough to influence work resumption among patients on sickness absence. Further research on stakeholders’ information asymmetry and its effect on the outcome of patients are necessary. The complexity of information asymmetry in disability management cannot be underestimated.
Occupational sunlight exposure, polymorphism of glutathione S-transferase M1, and senile cataract risk: Table 1
Authors: Saadat M , Farvardin-Jahromi M
Published: March 2006

Background:The pathogenesis of cataract is influenced by a number of factors including oxidative stress. Glutathione S-transferase (GST) catalyses the nucleophilic addition of the thiol of GST to electrophilic acceptors. It is important for detoxification of xenobiotics in order to protect tissues from oxidative damage.

Objectives:To examine whether the interaction of polymorphism of GSTM1 gene and occupational sunlight exposure modulate the risk of cataract.

Methods:Blood samples from 95 subjects with cataract and 95 age and sex matched healthy persons were collected. The genotypes of GSTM1 were determined using PCR.

Results:The null genotype of GSTM1 was associated with an increase in cataract risk in the indoor workplace, but this association was not significant in the outdoor subjects.

Conclusion:The active genotype of GSTM1 has lost its protective role in persons who work outdoors. It is suggested that activity of the GSTμ enzyme may be inhibited in the human lens after occupational exposure to UV light.
A probabilistic assessment of the impact of interventions on oncology nurses’ exposure to antineoplastic agents
Authors: Meijster T , Fransman W , van Hemmen J , Kromhout H , Heederik D , Tielemans E
Published: March 2006

Objective:The main goal was to investigate the potential of a probabilistic approach for exposure assessment and use this information to evaluate the impact of a complex of policy actions/interventions on dermal exposure to antineoplastic agents among oncology nurses. The central theme of this study was to make optimal use of existing data, supplemented only with limited additional information from a questionnaire survey.

Methods:A task based exposure model was used to estimate dermal exposure of the hands among oncology nurses in non-academic hospitals in the Netherlands. Monte Carlo simulation was used to integrate information from available (exposure) studies and generate exposure distributions for the total population of oncology nurses in both pre- and post-intervention situation. Graphs and descriptive statistics of the simulated exposure distributions were used to evaluate trends in population exposure.

Results:The inventory showed that important intervention occurred in the preparation and administering of antineoplastic agents and in the handling of urine. Hardly any changes were identified in de nursing tasks. The use of gloves seemed to have decreased for a number of tasks. The results of the analysis show that the interventions did not affect the median exposure. However frequencies of occurrence of individuals with very high and very low total dermal exposures decreased substantially in the post-intervention situation. Analysis of the effect of pregnancy showed that pregnancy is very unlikely to influence exposure or any of the key input variables.

Conclusions:The present study shows that the probabilistic approach adds valuable information to deterministic exposure assessment, especially when extrapolating data on a subpopulation to populations of individuals at large. The results show that the identified changes in the past decade in Dutch non-academic hospitals resulted in changes in the exposure distribution of antineoplastic agents among oncology nurses.
Occupational exposure to power frequency magnetic fields and risk of non-Hodgkin lymphoma
Authors: Karipidis K , Benke G , Sim M , Fritschi L , Yost M , Armstrong B , Hughes A M , Grulich A , Vajdic C M , Kaldor J , Kricker A
Published: March 2006

Objectives:To investigate the risk of non-Hodgkin lymphoma (NHL) using a job-exposure matrix (JEM) to assess exposure to occupational magnetic fields at the power frequencies of 50/60 Hz.

Methods:The study population consisted of 694 cases of NHL, first diagnosed between 1 January 2000 and 31 August 2001, and 694 controls from two regions in Australia, matched by age, sex and region of residence. A detailed occupational history was given by each subject. Exposure to power frequency magnetic fields was estimated using a population-based JEM which was specifically developed in the United States to assess occupational magnetic field exposure. The cumulative exposure distribution was divided into quartiles and adjusted odds ratios were calculated using the lowest quartile as the referent group.

Results:For the total work history, the odds ratio (OR) for workers in the upper quartile of exposure was 1.48 (95% CI 1.02 to 2.16) compared to the referent (p value for trend was 0.006). When the exposure was lagged by 5 years the OR was 1.59 (95% CI 1.07 to 2.36) (p value for trend was 0.003). Adjusting for other occupational exposures did not significantly alter the results.

Conclusions:These findings provide weak support for the hypothesis that occupational exposure to 50/60 Hz magnetic fields increases the risk of NHL.
Temporal associations between daily counts of fungal spores and asthma exacerbations
Authors: Atkinson R W , Strachan D P , Anderson H R , Hajat S , Emberlin J
Published: March 2006

Background:Outdoor aeroallergens are one of a number of environmental factors thought to precipitate asthma exacerbations.

Aims:To investigate the short term associations between daily fungal spore concentrations and indicators of daily asthma exacerbations in a large urban population.

Methods:Daily counts of visits for asthma to family physicians and hospital accident and emergency (A&E) departments and emergency hospital admissions in London 1992–93 were compiled. Daily concentrations of fungal spores (30 species), daily average temperature, humidity, and concentrations of pollen and outdoor air pollution were also compiled. The analysis was restricted to the period when fungal spores were most prevalent (June to mid October). Non-parametric regression time series methods were used to assess associations controlling for seasonality, day of week, and meteorological factors. The sensitivity of the findings to the inclusion of pollen and air pollution into the models was also assessed.

Results:In children aged 0–14 years the relative risks for increases in the number of A&E visits and hospital admissions associated with changes in fungal spore concentrations from the lower to upper quartiles were 1.06 (95% CI 0.94 to 1.18) and 1.07 (0.97 to 1.19) respectively. The addition of pollen or air pollutants had little impact on the observed associations. A number of individual sporetaxa,in particularAlternaria, Epicoccum, Agrocybe, Mildews, and both coloured and colourless Basidiospores and Ascospores, were associated with increases in the number of emergency visits and hospital admissions for asthma, although the precision of these estimates were low. No evidence was found for associations in adults.

Conclusions:Fungal spore concentrations may provoke or exacerbate asthma attacks in children resulting in visits to A&E departments and emergency hospital admissions. These findings were unlikely to be due to confounding by other environmental factors. The associations were comparable to those observed for ambient air pollution from similarly designed studies.
Noise exposure and hearing loss prevention programmes after 20 years of regulations in the United States
Authors: Daniell W E , Swan S S , McDaniel M M , Camp J E , Cohen M A , Stebbins J G
Published: March 2006

Objectives:To evaluate noise exposures and hearing loss prevention efforts in industries with relatively high rates of workers’ compensation claims for hearing loss.

Methods:Washington State workers’ compensation records were used to identify up to 10 companies in each of eight industries. Each company (n = 76) was evaluated by a management interview, employee personal noise dosimetry (n = 983), and employee interviews (n = 1557).

Results:Full-shift average exposures were ⩾85 dBA for 50% of monitored employees, using Occupational Safety and Health Administration (OSHA) parameters with a 5 dB exchange rate (Lave), but 74% were ⩾85 dBA using a 3 dB exchange rate (Leq). Only 14% had Lave⩾90 dBA, but 42% had Leq⩾90 dBA. Most companies conducted noise measurements, but most kept no records, and consideration of noise controls was low in all industries. Hearing loss prevention programmes were commonly incomplete. Management interview scores (higher score = more complete programme) showed significant associations with percentage of employees having Lave⩾85 dBA and presence of a union (multiple linear regression; R2 = 0.24). Overall, 62% of interviewed employees reported always using hearing protection when exposed. Protector use showed significant associations with percentage of employees specifically required to use protection, management score, and average employee time spent ⩾95 dBA (R2 = 0.65).

Conclusions:The findings raise serious concerns about the adequacy of prevention, regulation, and enforcement strategies in the United States. The percentage of workers with excessive exposure was 1.5–3 times higher using a 3 dB exchange rate instead of the OSHA specified 5 dB exchange rate. Most companies gave limited or no attention to noise controls and relied primarily on hearing protection to prevent hearing loss; yet 38% of employees did not use protectors routinely. Protector use was highest when hearing loss prevention programmes were most complete, indicating that under-use of protection was, in some substantial part, attributable to incomplete or inadequate company efforts.
GENERATION AND EVOLUTION OF DARK-SOLITON TRAINS IN ONE-DIMENSIONAL BOSE–EINSTEIN CONDENSATES
Authors: TIAN QIANG , WANG JINGPING
Published: March 2006

Generation and evolution of dark-soliton trains are studied. We focus on the dynamics resulting from large initial excitations in one-dimensional Bose–Einstein condensates trapped by a harmonic potential numerically. We consider three different techniques of controllable creation of multisolition structures (soliton trains). Multisoliton effects are discussed.
Septo-Hippocampal Networks in Chronically Epileptic Rats: Potential Antiepileptic Effects of Theta Rhythm Generation
Authors: Colom Luis V. , García-Hernández Antonio , Castañeda Maria T. , Perez-Cordova Miriam G. , Garrido-Sanabria Emilio R.
Published: March 2006

A series of experiments was carried out testing the hypothesis that the septal region decreases the hippocampal susceptibility to hyperexcitability states through theta rhythm generation. Medial septal neurons were simultaneously recorded with hippocampal field potentials to investigate the septo-hippocampal function in the pilocarpine model of chronic epilepsy. The theta rhythm from chronically epileptic rats had lower amplitude (20% less) and higher frequency than controls (from 3.38 to 4.25 Hz), suggesting that both generator and pacemaker structures are affected during the epileptic process. At the cellular level, the group of rhythmically bursting firing medial septal neurons, in the epileptic animals, significantly and chronically increased their firing rates in relation to controls (from 13.86 to 29.14 spikes/s). Peristimulus histograms performed around hippocampal sharp waves showed that all high-frequency firing neurons, including rhythmically bursting neurons and most slow firing neurons, decreased firing rates immediately after hippocampal epileptic discharges. Thus inhibitory hippocampo-septal influences prevail during hippocampal epileptic discharges. The occurrence of epileptic discharges was reduced 86–97% of the number observed during spontaneous theta and theta induced by sensory (tail pinch) or chemical stimulation (carbachol), suggesting that the presence of the theta state regardless of how it was produced was responsible for the reduction in epileptic discharge frequency. The understanding of the theta rhythm “anti-epileptic” effect at the cellular and molecular levels may result in novel therapeutic approaches dedicated to protect the brain against abnormal excitability states.
Association of
CYP17, CYP19, CYP1B1
, and
COMT
Polymorphisms with Serum and Urinary Sex Hormone Concentrations in Postmenopausal Women
Authors: Tworoger Shelley S. , Chubak Jessica , Aiello Erin J. , Ulrich Cornelia M. , Atkinson Charlotte , Potter John D. , Yasui Yutaka , Stapleton Patricia L. , Lampe Johanna W. , Farin Federico M. , Stanczyk Frank Z. , McTiernan Anne
Published: March 2006

Women with high circulating estrogen concentrations have an increased risk of breast cancer; thus, it is important to understand factors, including genetic variability, that influence estrogen concentrations. Several genetic polymorphisms that may influence sex hormone concentrations have been identified, including CYP17 (5′-untranslated region T→C), CYP19 [intron 4 (TTTA)n = 7–13 and a 3-bp deletion (−3)], CYP1B1 (Val432Leu), and COMT (Val108/158Met). We examined associations between these polymorphisms and serum concentrations of estrogens, androgens, and sex hormone-binding globulin and urinary concentrations of 2- and 16α-hydroxyestrone in 171 postmenopausal women, using data from the prerandomization visit of an exercise clinical trial. Participants were sedentary, not taking hormone therapy, and had a body mass index >24.0. Compared with noncarriers, women carrying two CYP19 7r(−3) alleles had 26% lower estrone (P < 0.001), 19% lower estradiol (P = 0.01), 23% lower free estradiol (P = 0.01), and 22% higher sex hormone-binding globulin concentrations (P = 0.06). Compared with noncarriers, women carrying at least one CYP19 8r allele had 20% higher estrone (P = 0.003), 18% higher estradiol (P = 0.02), and 21% higher free estradiol concentrations (P = 0.01). Women with the COMT Met/Met genotype had 28% higher 2-hydroxyestrone (P = 0.08) and 31% higher 16α-hydroxyestrone concentrations (P = 0.02), compared with Val/Val women. Few associations were found for CYP17 and CYP1B1 or with serum androgen concentrations. This study provides further evidence that genetic variation may appreciably alter sex hormone concentrations in postmenopausal women not taking hormone therapy.