bluuebunny/crossref_metadata_2025 huggingface dataset:
The Acidic Repetitive Domain of the
Magnetospirillum gryphiswaldense
MamJ Protein Displays Hypervariability but Is Not Required for Magnetosome Chain Assembly
Authors: Scheffel André , Schüler Dirk
Published: June 2007

Magnetotactic bacteria navigate along the earth's magnetic field using chains of magnetosomes, which are intracellular organelles comprising membrane-enclosed magnetite crystals. The assembly of highly ordered magnetosome chains is under genetic control and involves several specific proteins. Based on genetic and cryo-electron tomography studies, a model was recently proposed in which the acidic MamJ magnetosome protein attaches magnetosome vesicles to the actin-like cytoskeletal filament formed by MamK, thereby preventing magnetosome chains from collapsing. However, the exact functions as well as the mode of interaction between MamK and MamJ are unknown. Here, we demonstrate that several functional MamJ variants from
Magnetospirillum gryphiswaldense
and other magnetotactic bacteria share an acidic and repetitive central domain, which displays an unusual intra- and interspecies sequence polymorphism, probably caused by homologous recombination between identical copies of Glu- and Pro-rich repeats. Surprisingly,
mamJ
mutant alleles in which the central domain was deleted retained their potential to restore chain formation in a Δ
mamJ
mutant, suggesting that the acidic domain is not essential for MamJ's function. Results of two-hybrid experiments indicate that MamJ physically interacts with MamK, and two distinct sequence regions within MamJ were shown to be involved in binding to MamK. Mutant variants of MamJ lacking either of the binding domains were unable to functionally complement the Δ
mamJ
mutant. In addition, two-hybrid experiments suggest both MamK-binding domains of MamJ confer oligomerization of MamJ. In summary, our data reveal domains required for the functions of the MamJ protein in chain assembly and maintenance and provide the first experimental indications for a direct interaction between MamJ and the cytoskeletal filament protein MamK.
Regulation of the α-Crystallin Geneacr2by the MprAB Two-Component System ofMycobacterium tuberculosis
Authors: Pang Xiuhua , Howard Susan T.
Published: June 2007

Coordinated regulation of molecular chaperones is an important feature of the bacterial stress response. The small molecular chaperone geneacr2ofMycobacterium tuberculosisis activated by exposure to several stresses, including heat and the detergent sodium dodecyl sulfate (SDS). In this study, we show thatacr2is directly regulated by the MprAB two-component system, and that MprAB has both positive and negative effects onacr2expression. mRNA analyses showed thatacr2expression levels were lower under SDS stress and control conditions but higher under heat shock in anmprABdeletion mutant than they were in the parental strain. Parental expression patterns were restored in anmprAB-complemented strain. Western blotting using an anti-Acr2 antibody showed that Acr2 protein synthesis correlated with mRNA levels. Primer extension identified one transcriptional start point (TSP) foracr2in all three strains under control and stress conditions. Electrophoresis mobility shift assays revealed multiple MprA binding sites in theacr2promoter, including one downstream and three upstream of theacr2TSP, with one overlapping the binding sites predicted for SigE, SigH, and HspR. DNA footprinting confirmed that MprA protected large sections of theacr2promoter region. Expression of several housekeeping genes under SDS stress also was evaluated, revealing the upregulation of large molecular chaperone genes and, unexpectedly,sigA, with slightly lowersigAmRNA levels detected in themprABdeletion mutant than in the wild type. In contrast to Acr2, SigA protein synthesis did not correlate with mRNA expression. Overall, the data indicated that MprA has complex interactions with theacr2promoter and indirect effects on major housekeeping genes.
Structural and Functional Analyses of the Major Outer Membrane Protein ofChlamydia trachomatis
Authors: Sun Guifeng , Pal Sukumar , Sarcon Annahita K. , Kim Soyoun , Sugawara Etsuko , Nikaido Hiroshi , Cocco Melanie J. , Peterson Ellena M. , de la Maza Luis M.
Published: June 2007

Chlamydia trachomatisis a major pathogen throughout the world, and preventive measures have focused on the production of a vaccine using the major outer membrane protein (MOMP). Here, in elementary bodies and in preparations of the outer membrane, we identified native trimers of the MOMP. The trimers were stable under reducing conditions, although disulfide bonds appear to be present between the monomers of a trimer and between trimers. Cross-linking of the outer membrane complex demonstrated that the MOMP is most likely not in a close spatial relationship with the 60- and 12-kDa cysteine-rich proteins. Extraction of the MOMP fromChlamydiaisolates under nondenaturing conditions yielded the trimeric conformation of this protein as shown by cross-linking and analysis by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis with different concentrations of acrylamide. Using circular dichroism spectroscopy, we determined that the trimers were formed mainly of β-pleated sheet structures in detergent micelles. Using a liposomal swelling assay, the MOMP was found to have porin activity, and the size of the pore was estimated to be approximately 2 nm in diameter. The trimers were found to be stable in SDS at temperatures ranging from 4 to 37°C and over a pH range of 5.0 to 8.0. In addition, the trimers of MOMP were found to be resistant to digestion with trypsin. In conclusion, these results show that the native conformation of the MOMP ofC. trachomatisis a trimer with predominantly a β-sheet structure and porin function.
Proteomic and Transcriptomic Analysis of Extracellular Proteins and mRNA Levels inThermobifida fuscaGrown on Cellobiose and Glucose
Authors: Chen Shaolin , Wilson David B.
Published: June 2007

Thermobifida fuscasecretes proteins that carry out plant cell wall degradation. Using two-dimensional electrophoresis, the extracellular proteome ofT. fuscagrown on cellobiose was compared to that of cells grown on glucose. Extracellular proteins, the expression of which is induced by cellobiose, mainly are cellulases and cellulose-binding proteins. Other major extracellular proteins induced by cellobiose include a xylanase (Xyl10A) and two unknown proteins, the C-terminal regions of which are homologous to a lytic transglycosylase goose egg white lysozyme domain and an NLPC_P60 domain (which defines a family of cell wall peptidases), respectively. Transcriptional analysis of genes encoding cellobiose-induced proteins suggests that their expression is controlled at the transcriptional level and that their expression also is induced by cellulose. Some other major extracellular proteins produced byT. fuscagrown on both cellobiose and glucose include Lam81A and three unknown proteins that are homologous to aminopeptidases and xylanases or that contain a putative NLPC_P60 domain.
Escherichia coli
K1-Specific Bacteriophage CUS-3 Distribution and Function in Phase-Variable Capsular Polysialic Acid O Acetylation
Authors: King Michael R. , Vimr Ross P. , Steenbergen Susan M. , Spanjaard Lodewijk , Plunkett Guy , Blattner Frederick R. , Vimr Eric R.
Published: June 2007

Escherichia coli
K1 is the leading cause of human neonatal sepsis and meningitis and is important in other clinical syndromes of both humans and domestic animals; in this strain the polysialic acid capsule (K1 antigen) functions by inhibiting innate immunity. Recent discovery of the phase-variable capsular O acetylation mechanism indicated that the O-acetyltransferase gene,
neuO
, is carried on a putative K1-specific prophage designated CUS-3 (E. L.
Deszo, S. M. Steenbergen, D. I. Freedberg, and E. R. Vimr
, Proc. Natl. Acad. Sci. USA
102:
5564-5569, 2005). Here we describe the isolation and characterization of a CUS-3 derivative (CUS-3a), demonstrating its morphology, lysogenization of a sensitive host, and the distribution of CUS-3 among a collection of 111 different K1 strains. The 40,207-bp CUS-3 genome was annotated from the strain RS218 genomic DNA sequence, indicating that most of the 63 phage open reading frames have their closest homologues in one of seven different lambdoid phages. Translational fusion of a reporter
lacZ
fragment to the hypervariable poly-Ψ domain facilitated measurement of phase variation frequencies, indicating no significant differences between switch rates or effects on rates of the methyl-directed mismatch repair system. PCR analysis of poly-Ψ domain length indicated preferential loss or gain of single 5′-AAGACTC-3′ nucleotide repeats. Analysis of a K1 strain previously reported as “locked on” indicated a poly-Ψ region with the least number of heptad repeats compatible with in-frame
neuO
expression. The combined results establish CUS-3 as an active mobile contingency locus in
E. coli
K1, indicating its capacity to mediate population-wide capsule variation.
Function of Periplasmic Hydrogenases in the Sulfate-Reducing Bacterium
Desulfovibrio vulgaris
Hildenborough
Authors: Caffrey Sean M. , Park Hyung-Soo , Voordouw Johanna K. , He Zhili , Zhou Jizhong , Voordouw Gerrit
Published: June 2007

The sulfate-reducing bacterium
Desulfovibrio vulgaris
Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation of molecular hydrogen. These include an [Fe] hydrogenase, an [NiFeSe] hydrogenase, and two [NiFe] hydrogenases encoded by the
hyd
,
hys
,
hyn1
, and
hyn2
genes, respectively. In order to understand their cellular functions, we have compared the growth rates of existing (
hyd
and
hyn1
) and newly constructed (
hys
and
hyn-1 hyd
) mutants to those of the wild type in defined media in which lactate or hydrogen at either 5 or 50% (vol/vol) was used as the sole electron donor for sulfate reduction. Only strains missing the [Fe] hydrogenase were significantly affected during growth with lactate or with 50% (vol/vol) hydrogen as the sole electron donor. When the cells were grown at low (5% [vol/vol]) hydrogen concentrations, those missing the [NiFeSe] hydrogenase suffered the greatest impairment. The growth rate data correlated strongly with gene expression results obtained from microarray hybridizations and real-time PCR using mRNA extracted from cells grown under the three conditions. Expression of the
hys
genes followed the order 5% hydrogen > 50% hydrogen > lactate, whereas expression of the
hyd
genes followed the reverse order. These results suggest that growth with lactate and 50% hydrogen is associated with high intracellular hydrogen concentrations, which are best captured by the higher activity, lower affinity [Fe] hydrogenase. In contrast, growth with 5% hydrogen is associated with a low intracellular hydrogen concentration, requiring the lower activity, higher affinity [NiFeSe] hydrogenase.
Regulation of
pyr
Gene Expression in
Mycobacterium smegmatis
by PyrR-Dependent Translational Repression
Authors: Fields Christopher J. , Switzer Robert L.
Published: June 2007

Regulation of pyrimidine biosynthetic (
pyr
) genes by a transcription attenuation mechanism that is mediated by the PyrR mRNA-binding regulatory protein has been demonstrated for numerous gram-positive bacteria. Mycobacterial genomes specify
pyrR
genes and contain obvious PyrR-binding sequences in the initially transcribed regions of their
pyr
operons, but transcription antiterminator and attenuation terminator sequences are absent from their
pyr
5′ leader regions. This work demonstrates that repression of
pyr
operon expression in
Mycobacterium smegmatis
by exogenous uracil requires the
pyrR
gene and the
pyr
leader RNA sequence for binding of PyrR. Plasmids containing the
M. smegmatis pyr
promoter-leader region translationally fused to
lacZ
also displayed
pyrR
-dependent repression, but transcriptional fusions of the same sequences to a
lacZ
gene that retained the
lacZ
ribosome-binding site were not regulated by PyrR plus uracil. We propose that PyrR regulates
pyr
expression in
M. smegmatis
, other mycobacteria, and probably in numerous other bacteria by a translational repression mechanism in which nucleotide-regulated binding of PyrR occludes the first ribosome-binding site of the
pyr
operon.
Metabolic equivalents during the 10-m shuttle walking test for post-myocardial infarction patients
Authors: Woolf-May K , Ferrett D
Published: June 2007

Objective:

Comorbidities are found to affect metabolic equivalents (METs). Therefore the main objective of this study was to compare METs (1 MET: oxygen uptake (Vo2) 3.5 ml/kg/min) during an incremental shuttle walking test (SWT) between non-cardiac and post-myocardial infarction (MI) men, and secondly to determine any differences in Vo2(ml/kg/min) between flat treadmill walking and the turning during the shuttle walking in non-cardiac subjects.

Design:

Comparative study.

Subjects:

Thirty one post-MI (mean (SD) age 63.5 (6.5), range 53–77 years) from phase IV cardiac rehabilitation and 19 non-cardiac (64.6 (7.5), range 51–76 years) men participated.

Methods:

All subjects performed an SWT, and non-cardiac subjects a treadmill test of similar protocol. Throughout both, the subject’s Vo2was measured.

Results:

Analysis comparing lines of regression showed METs at 1.12 to 4.16 mph were higher (p<0.001) for post-MIs versus non-cardiac subjects. For non-cardiac subjects, there were no differences between the treadmill test and SWT (p>0.9) and LoA showed acceptable agreement in METs between treadmill vs SWT, mean difference −1.1 (8.8) (1.96SD).

Conclusion:

It would appear that for asymptomatic individuals it is appropriate to apply established METs for flat walking to the SWT. However, the significantly higher METs for the post-MI compared with the non-cardiac subjects indicates the need for caution when using METs derived from healthy subjects in the prescription of exercise for myocardial patients.
Influence of residual stress/strain on the biomechanical stability of vulnerable coronary plaques: potential impact for evaluating the risk of plaque rupture
Authors: Ohayon Jacques , Dubreuil Olivier , Tracqui Philippe , Le Floc'h Simon , Rioufol Gilles , Chalabreysse Lara , Thivolet Françoise , Pettigrew Roderic I. , Finet Gérard
Published: June 2007

In a vulnerable plaque (VP), rupture often occurs at a site of high stress within the cap. It is also known that vessels do not become free of stress when all external loads are removed. Previous studies have shown that such residual stress/strain (RS/S) tends to make the stress distribution more uniform throughout the media of a normal artery. However, the influence of RS/S on the wall stress distribution in pathological coronaries remains unclear. The aim of this study was to investigate the effects of RS/S on the biomechanical stability of VPs. RS/S patterns were studied ex vivo in six human vulnerable coronary plaque samples. Because the existence of RS/S can only be assessed by releasing it, the opening angle technique was the experimental approach used to study the geometrical opening configurations of the diseased arteries, producing an arterial wall in a near-zero stress state. Reciprocally, these opening geometries were used in finite element simulations to reconstruct the RS/S distributions in closed arteries. It was found that the RS/S 1) is not negligible, 2) dramatically affects the physiological peak stress amplitude in the thin fibrous cap, 3) spotlights some new high stress areas, and 4) could be a landmark of the lipid core's developmental process within a VP. This study demonstrates that plaque rupture is not to be viewed as a consequence of intravascular pressure alone, but rather of a subtle combination of external loading and intraplaque RS/S.
Spontaneous baroreflex control of heart rate during exercise and muscle metaboreflex activation in heart failure
Authors: Iellamo Ferdinando , Sala-Mercado Javier A. , Ichinose Masashi , Hammond Robert L. , Pallante Marco , Ichinose Tomoko , Stephenson Larry W. , O'Leary Donal S.
Published: June 2007

In heart failure (HF), there is a reduced baroreflex sensitivity at rest, and during dynamic exercise there is enhanced muscle metaboreflex activation (MRA). However, how the arterial baroreflex modulates HR during exercise is unknown. We tested the hypothesis that spontaneous baroreflex sensitivity (SBRS) is attenuated during exercise in HF and that MRA further depresses SBRS. In seven conscious dogs we measured heart rate (HR), cardiac output, and left ventricular systolic pressure at rest and during mild and moderate dynamic exercise, before and during MRA (via imposed reductions of hindlimb blood flow), and before and after induction of HF (by rapid ventricular pacing). SBRS was assessed by the sequences method. In control, SBRS was reduced from rest with a progressive resetting of the baroreflex stimulus-response relationship in proportion to exercise intensity and magnitude of MRA. In HF, SBRS was significantly depressed in all settings; however, the changes with exercise and MRA occurred with a pattern similar to the control state. As in control, the baroreflex stimulus-response relationship showed an intensity- and muscle metaboreflex (MMR)-dependent rightward and upward shift. The results of this study indicate that HF induces an impairment in baroreflex control of HR at rest and during exercise, although the effects of exercise and MRA on SBRS occur with a similar pattern as in control, indicating the persistence of some vagal activity.
TGF-β1 stimulates human AT1receptor expression in lung fibroblasts by cross talk between the Smad, p38 MAPK, JNK, and PI3K signaling pathways
Authors: Martin Mickey M. , Buckenberger Jessica A. , Jiang Jinmai , Malana Geraldine E. , Knoell Daren L. , Feldman David S. , Elton Terry S.
Published: June 2007

Both angiotensin II (ANG II) and transforming growth factor-β1 (TGF-β1) are thought to be involved in mediating pulmonary fibrosis. Interactions between the renin-angiotensin system (RAS) and TGF-β1 have been well documented, with most studies describing the effect of ANG II on TGF-β1 expression. However, recent gene expression profiling experiments demonstrated that the angiotensin II type 1 receptor (AT1R) gene was a novel TGF-β1 target in human adult lung fibroblasts. In this report, we show that TGF-β1 augments human AT1R (hAT1R) steady-state mRNA and protein levels in a dose- and time-dependent manner in primary human fetal pulmonary fibroblasts (hPFBs). Nuclear run-on experiments demonstrate that TGF-β1 transcriptionally activates the hAT1R gene and does not influence hAT1R mRNA stability. Pharmacological inhibitors and specific siRNA knockdown experiments demonstrate that the TGF-β1 type 1 receptor (TβRI/ALK5), Smad2/3, and Smad4 are essential for TGF-β1-stimulated hAT1R expression. Additional pharmacological inhibitor and small interference RNA experiments also demonstrated that p38 MAPK, JNK, and phosphatidylinositol 3-kinase (PI3K) signaling pathways are also involved in the TGF-β1-stimulated increase in hAT1R density. Together, our results suggest an important role for cross talk among Smad, p38 MAPK, JNK, and PI3K pathways in mediating the augmented expression of hAT1R following TGF-β1 treatment in hPFB. This study supports the hypothesis that a self-potentiating loop exists between the RAS and the TGF-β1 signaling pathways and suggests that ANG II and TGF-β1 may cooperate in the pathogenesis of pulmonary fibrosis. The synergy between these systems may require that both pathways be simultaneously inhibited to treat fibrotic lung disease.
The Young Mouse Heart Is Composed of Myocytes Heterogeneous in Age and Function
Authors: Rota Marcello , Hosoda Toru , De Angelis Antonella , Arcarese Michael L. , Esposito Grazia , Rizzi Roberto , Tillmanns Jochen , Tugal Derin , Musso Ezio , Rimoldi Ornella , Bearzi Claudia , Urbanek Konrad , Anversa Piero , Leri Annarosa , Kajstura Jan
Published: June 2007

The recognition that the adult heart continuously renews its myocyte compartment raises the possibility that the age and lifespan of myocytes does not coincide with the age and lifespan of the organ and organism. If this were the case, myocyte turnover would result at any age in a myocardium composed by a heterogeneous population of parenchymal cells which are structurally integrated but may contribute differently to myocardial performance. To test this hypothesis, left ventricular myocytes were isolated from mice at 3 months of age and the contractile, electrical, and calcium cycling characteristics of these cells were determined together with the expression of the senescence-associated protein p16
INK4a
and telomere length. The heart was characterized by the coexistence of young, aged, and senescent myocytes. Old nonreplicating, p16
INK4a
-positive, hypertrophied myocytes with severe telomeric shortening were present together with young, dividing, p16
INK4a
-negative, small myocytes with long telomeres. A class of myocytes with intermediate properties was also found. Physiologically, evidence was obtained in favor of the critical role that action potential (AP) duration and
I
CaL
play in potentiating Ca
2+
cycling and the mechanical behavior of young myocytes or in decreasing Ca
2+
transients and the performance of senescent hypertrophied cells. The characteristics of the AP appeared to be modulated by the transient outward K
+
current
I
to
which was influenced by the different expression of the K
+
channels subunits. Collectively, these observations at the physiological and structural cellular level document that by necessity the heart has to constantly repopulate its myocyte compartment to replace senescent poorly contracting myocytes with younger more efficient cells. Thus, cardiac homeostasis and myocyte turnover regulate cardiac function.
Essential Role of Extracellular SOD in Reparative Neovascularization Induced by Hindlimb Ischemia
Authors: Kim Ha Won , Lin Angela , Guldberg Robert E. , Ushio-Fukai Masuko , Fukai Tohru
Published: June 2007

Neovascularization is an important physiological repair mechanism in response to ischemic injury, and its process is dependent on reactive oxygen species (ROS). Overproduction of superoxide anion (O
2
·−
) rather contributes to various cardiovascular diseases. The extracellular superoxide dismutase (ecSOD) is one of the major antioxidant enzymes against O
2
·−
in blood vessels; however, its role in neovascularization induced by tissue ischemia is unknown. Here we show that hindlimb ischemia of mice stimulates a significant increase in ecSOD activity in ischemic tissues where ecSOD protein is highly expressed at arterioles. In mice lacking ecSOD, ischemia-induced increase in blood flow recovery, collateral vessel formation, and capillary density are significantly inhibited. Impaired neovascularization in ecSOD
−/−
mice is associated with enhanced O
2
·−
production, TUNEL-positive apoptotic cells and decreased levels of NO
2
−
/NO
3
−
and cGMP in ischemic tissues as compared with wild-type mice, and it is rescued by infusion of the SOD mimetic tempol. Recruitment of inflammatory cells into ischemic tissues as well as numbers of inflammatory cells and endothelial progenitor cells (c-kit
+
/CD31
+
cells) in both peripheral blood and bone marrow (BM) are significantly reduced in these knockout mice. Of note, ecSOD expression is markedly increased in BM after ischemia. NO
2
−
/NO
3
−
and cGMP levels are decreased in ecSOD
−/−
BM. Transplantation of wild-type BM into ecSOD
−/−
mice rescues the defective neovascularization. Thus, ecSOD in BM and ischemic tissues induced by hindlimb ischemia may represent an important compensatory mechanism that blunts the overproduction of O
2
·−
, which may contribute to reparative neovascularization in response to ischemic injury.
Role of Asymmetric Dimethylarginine in Vascular Injury in Transgenic Mice Overexpressing Dimethylarginie Dimethylaminohydrolase 2
Authors: Hasegawa Kazuhiro , Wakino Shu , Tatematsu Satoru , Yoshioka Kyoko , Homma Koichiro , Sugano Naoki , Kimoto Masumi , Hayashi Koichi , Itoh Hiroshi
Published: June 2007

Dimethylarginie dimethylaminohydrolase (DDAH) degrades asymmetric dimethylarginine (ADMA), an endogenous nitric oxide (NO) synthase inhibitor, and comprises 2 isoforms, DDAH1 and DDAH2. To investigate the in vivo role of DDAH2, we generated trangenic mice overexpressing DDAH2. The transgenic mice manifested reductions in plasma ADMA and elevations in cardiac NO levels but no changes in systemic blood pressure (SBP), compared with the wild-type mice. When infused into wild-type mice for 4 weeks, ADMA elevated SBP and caused marked medial thickening and perivascular fibrosis in coronary microvessels, which were accompanied by ACE protein upregulation and cardiac oxidative stress. The treatment with amlodipine reduced SBP but failed to ameliorate the ADMA-induced histological changes. In contrast, these changes were abolished in transgenic mice, with a reduction in plasma ADMA. In coronary artery endothelial cells, ADMA activated p38 MAP kinase and the ADMA-induced ACE upregulation was suppressed by p38 MAP kinase inhibition by SB203580. In wild-type mice, long-term treatment with angiotensin II increased plasma ADMA and cardiac oxidative stress and caused similar vascular injury. In transgenic mice, these changes were attenuated. The present study suggests that DDAH2/ADMA regulates cardiac NO levels but has modest effect on SBP in normal conditions. Under the circumstances where plasma ADMA are elevated, including angiotensin II–activated conditions, ADMA serves to contribute to the development of vascular injury and increased cardiac oxidative stress, and the overexpression of DDAH2 attenuates these abnormalities. Collectively, the DDAH2/ADMA pathway can be a novel therapeutic target for vasculopathy in the ADMA or angiotensin II–induced pathophysiological conditions.
The Law of the Dubai International Financial Centre: Common Law Oasis or Mirage Within the UAE?
Authors: Carballo Alejandro
Published: June 2007

Despite the increasing trends towards a reassertion of Shari'a within the Arab world, the Emirate of Dubai has recently created a world-class financial hub, the Dubai International Financial Centre (DIFC). DIFC is under an independent, common law-based, parallel legal system (outside the Dubai and the UAE federal legal systems) which is backed by an independent judicial system. However, there are still certain hindrances, such as the financial dependence of the DIFC courts and the harmful requirement (controlled by the Dubai judge) of "appropriate for enforcement" of DIFC decisions seeking outside enforcement.Furthermore, although DIFC legislation allows the application of a Shari'a-based national legislation (except for any provision contrary to any mandatory rule of a law in force in the DIFC), problems arise regarding the application of a-national Shari'a principles, mainly in Islamic Finance. Will common law oriented DIFC courts refer to recent British cases? In any case, it must be stated that even in the very unlikely situation of a challenge against DIFC laws on grounds of unconstitutionality (for being contrary to Art. 7), the pro-commercial approach of the Constitutional Chamber of the UAE Supreme Court, leads to conclude that no DIFC law would be strike down.
What Responsibility Do Courts Have to Hear Children's Voices?
Authors: Parkinson Patrick , Cashmore Judy
Published: June 2007

No social organization can hope to be built on the rights of its members unless there are mechanisms whereby those members may express themselves and wherein those expressions are taken seriously. Hearing what children say must therefore lie at the roots of any elaboration of children's rights. No society will have begun to perceive its children as rightholders until adults' attitudes and social structures are seriously adjusted towards making it possible for children to express views, and towards addressing them with respect (Eekelaar, 1992, p. 228).
Children and Young People's Participation Rights in Education
Authors: Smith Anne
Published: June 2007

The paper outlines a new orientation towards constructing childhood arising out of children's rights discourse, sociology of childhood and sociocultural theory. Children have traditionally lacked voice and visibility, but slowly a recognition of children's role as social actors who are active co-constructors of meaning and "experts" on childhood is emerging. The paper looks at how the childhood studies paradigm highlights the importance of participation rights for children and young people. The paper describes how these theoretical paradigms are being reflected in educational policy and practice. It analyses examples of research and practice on how children are encouraged and supported to be active participants and social actors in their early childhood, primary and secondary education settings. The paper argues that having participation rights and being a citizen are part of an ongoing learning process, and that what happens in educational settings give meaning to children's understanding of what it is to be an active and involved citizen.This paper examines the application of the new paradigm of 'children's studies' to the development of policy and practice relating to children's participation rights in education. Theory and research is used to develop a framework for the principles of effective participation, and then an example at each level (early childhood, primary and secondary) of how these principles have been put into practice in education analysed.
School Structural Characteristics, Student Effort, Peer Associations, and Parental Involvement
Authors: Stewart Endya B.
Published: June 2007

This research examines the extent to which individual-level and school structural variables are predictors of academic achievement among a sample of 10th-grade students abstracted from the National Educational Longitudinal Study database. A secondary analysis of the data produced the following findings. The study results show that individual-level predictors, such as student effort, parent—child discussion, and associations with positive peers, play a substantial role in increasing students' achievement. Furthermore, the results also suggest that school climate—in particular, the sense of school cohesion felt by students, teachers, and administrators—is important to successful student outcomes. In total, school structural characteristics were found to have relatively small effects on student achievement when compared with individual-level characteristics. Given these results, interventions aimed at improving academic achievement need take into consideration the impact of individual-level and school structural factors on students and their ability to succeed.
Recruiting Participants in End-of-Life Research
Authors: Kirchhoff Karin T. , Kehl Karen A.
Published: June 2007

A great deal of time, attention, and funding has been dedicated to research concerned with improving care at the end of life. However, sizes of samples for such research are reduced by recruitment problems unique to end-of-life studies, which limits their power and generalizability. In this article, experiences are shared and suggestions are offered to increase recruitment using 4 recent studies on end-of-life topics as examples. The issues in this article include those related to participants (patients or family members) and those related to the health care providers or systems. A researcher who is forewarned about higher-than-usual rates for lack of contact, refusals, and no-shows in end-of-life research can plan appropriately for the time and effort needed during the recruitment phase of the study.
Self-Efficacy and Its Association With Use of Diet-Related Behavioral Strategies and Reported Dietary Intake
Authors: Nothwehr Faryle
Published: June 2007

The construct of self-efficacy has been widely used in studies of dietary behavior change and is accepted as a helpful process indicator. This study examined associations between self-efficacy and use of specific diet-related behavioral strategies and reported dietary intake over time. Data are from two community surveys of rural adults conducted 1 year apart ( n = 354). Results indicate that changes in self-efficacy are positively associated with changes in strategy use but not dietary intake. Strategies may be thought of as leading to a particular level of dietary intake but are not the only influence on intake. Findings therefore confirm hypothesized associations between these components of the behavior change process. By attending to and measuring these specific links in the process, researchers and practitioners can better determine where behavioral interventions are succeeding and where they are breaking down.
Factors Influencing Lunchtime Food Choices Among Working Americans
Authors: Blanck Heidi M. , Yaroch Amy L. , Atienza Audie A. , Yi Sarah L. , Jian Zhang  , Mâsse Louise C.
Published: June 2007

There is growing interest in the usefulness of the workplace as a site for promotion of healthful food choices. The authors therefore analyzed data of U.S. adults ( N = 1,918) who reported working outside the home and eating lunch. The majority (84.0%) of workers had a break room. About one half (54.0%) purchased lunch ≥ 2 times/week, with higher percentages for males, Blacks, younger (age 18-34 years) versus older adults (age 55 years or older), and obese versus normal-weight persons. The most important lunch food choice value was convenience (34.3%), followed by taste (27.8%), cost (20.8%), and health (17.1%). The typical source for purchasing lunch was a fast-food restaurant (43.4%), followed by on-site cafeteria/snack shop (25.3%), full-service restaurant (16.9%), supermarket (5.2%), vending machine (4.4%), and convenience store (4.0%); younger adults and those less educated relied more on fast-food places. This study identifies individual factors and values that may influence future dietary health initiatives in the work site.
Dynamic recrystallisation of Mg–6Zn–2Nd–0·5Zr alloy
Authors: Zhou H. T. , Zhang Z. D. , Li Q.
Published: June 2007

Dynamic recrystallisation of Mg–6Zn–2Nd–0·5Zr alloy at temperature range from 543 to 693 K and strain rate from 0·001 to 1 s−1 are investigated. Flow softening is found to occur and all flow curves exhibit a peak with characteristics of dynamic recrystallisation and change significantly with temperature and strain rate. As a result of dynamic recrystallisation, the grains are greatly refined through dynamic recrystallisation, and the mean size of the recrystallised grain decreases with decreasing temperature or increasing Z parameter. By comparison of the grain sizes, 593 K is found to be the optimal deformation temperature. The yield strength and tensile strength of extruded Mg–6Zn–2Nd–0·5Zr alloy are 320 and 379 MPa respectively, higher than those of ZK60 alloy.
Effect of homogenisation conditions on recrystallisation in Al–Mg–Mn alloy AA 5454
Authors: Osman M. , Engler O. , Karhausen K. , Löchte L. , McLaren A. J.
Published: June 2007

The purpose of the present work is to understand the microstructure development and, particularly, to control the progress of recrystallisation in hot strip in the Al–Mg–Mn alloy AA 5454, which is typically used for the manufacture of structural automotive components. The chemical composition, together with the thermomechanical processing history of this material, has a strong influence on the microstructure of the product and the resulting properties as it is supplied to the customer. Electrical conductivity measurements, thermal analysis and electron microscopy have been carried out to characterise the evolution of precipitation state at various stages in the processing route. The conditions of the homogenisation heat treatment have been varied, and the effect on subsequent recrystallisation after hot rolling has been evaluated in both the as cast and rough rolled condition by optical microscopy techniques. Results indicate that the conditions of homogenisation heat treatment and roughing rolling are critical for the generation of a suitable recrystallised microstructure in AA 5454 hot strip. A new two stage homogenisation practice has been developed to expedite post-rolling recrystallisation in this alloy.
Mechanical properties of as cast microalloyed steels containing V, Nb and Ti
Authors: Najafi H. , Rassizadehghani J. , Halvaaee A.
Published: June 2007

Tensile, hardness and room temperature Charpy V notch impact tests were used to evaluate the variations in the mechanical properties of a low carbon cast steel containing combinations of vanadium, niobium and titanium in the as cast condition. Tensile and hardness test results indicate that good combinations of strength and ductility can be achieved by microalloying additions. Based on the TEM studies, random and interphase fine scale microalloy precipitates play a major role in the strengthening of the microalloyed heats. However, the presence of titanium leads to some reduction in the strength of the microalloyed heat. Coarse TiN particles can be responsible for this behaviour. On the other hand, microalloying additions significantly decrease the impact energy and lead to the dominance of cleavage facets on the fracture surfaces. It seems that heterogeneous nucleation of microalloy carbonitrides on dislocations along with coarse ferrite grains and pearlite colonies has triggered the brittle fracture in the microalloyed heats.
Gradient phase structure formation of polymer–polymer blend composites during melt spinning
Authors: Jiang C. , Chen Y. M. , Pan Z. J. , Lu W. G. , Yu C. B. , Zhu M. F.
Published: June 2007

Gradient inhomogeneous phase structure of polymer blends of low density polyethylene/ polyamide 6 (LDPE/PA6) and polypropylene/polystyrene (PP/PS) through melt spinning was investigated. Scanning electron microscopy (SEM) results showed that the gradient phase structure was in the opposite sense in the two systems. This morphology was attributed to the component properties and the radial variation of parameters including temperature, viscosity, axial velocity and stress in the spinning path.
Preparation and electromagnetic wave absorption properties of Co–P/SrFe12O19 magnetic powder
Authors: Pan X. F. , Mu G. H. , Chen N. , Gan K. K. , Yang K. , Gu M. Y.
Published: June 2007

The Co–P/SrFe12O19 magnetic nanocomposite powder was prepared by electroless plating enhanced by ultrasonic wave agitation. The morphology, crystal structure and microwave absorption properties of the Co–P coated powder were studied using field emission scanning electron microscopy, XRD, EDX and a vector network analyser. The results show that the powder possesses excellent microwave absorption properties. The maximum microwave loss of the composite powder reaches −27·1 dB. The bandwidth with the loss above −20 dB reaches 1·6 GHz.
Case-only study of interactions between metabolic enzymes and smoking in colorectal cancer
Authors: Fan Chunhong , Jin Mingjuan , Chen Kun , Zhang Yongjing , Zhang Shuangshuang , Liu Bing
Published: June 2007

Background

Gene-gene and gene-environment interactions involved in the metabolism of carcinogens may increase the risk of cancer. Our objective was to measure the interactions between common polymorphisms of P450 (CYP1A2, CYP1B1, CYP2E1), GSTM1 and T1, SULT1A1 and cigarette smoking in colorectal cancer (CRC).

Methods

A case-only design was conducted in a Chinese population including 207 patients with sporadic CRC. Unconditional logistic regression analysis was performed adjusting for age, gender, alcohol consumption, and cigarette smoking.

Results

The interaction odds ratio (COR) for the gene-gene interaction between CYP1B1 1294G and SULT1A1 638A allele was 2.68 (95% CI: 1.16–6.26). The results of the gene-environment analyses revealed that an interaction existed between cigarette smoking and the CYP1B1 1294G allele for CRC (COR = 2.62, 95%CI: 1.01–6.72), the COR for the interaction of CYP1B1 1294G and smoking history > 35 pack-years was 3.47 (95%CI: 1.12–10.80). No other significant gene-gene and gene-environment interactions were observed.

Conclusion

Our results showed that the interaction between polymorphisms in CYP1B1 1294G and SULT1A1*2 may play a significant role on CRC in the Chinese population. Also, it is suggested that the association between cigarette smoking and CRC could be differentiated by the CYP1B1 1294G allele.
Spinal NKCC1 Blockade Inhibits TRPV1-Dependent Referred Allodynia
Authors: Pitcher Mark H , Price Theodore J , Entrena Jose M , Cervero Fernando
Published: June 2007

Background:

The Na+, K+, 2Cl− type I cotransporter (NKCC1) and TRPV1 receptors, at the level of the dorsal horn, have been implicated in mediating allodynia in response to an inflammatory insult. The NKCC1 cotransporter regulates intracellular [Cl−] and thus the magnitude and polarity of GABAA receptor responses in neurons. TRPV1 receptors transduce diverse chemical and natural stimuli in nociceptors and are critical for inflammatory hyperalgesia.

Results:

Here we have tested the role of spinal NKCC1 cotransporters and TRPV1 receptors in referred allodynia in a model of visceral hyperalgesia in mice. Intrathecal (IT) injection of the NKCC1 inhibitor bumetanide (BUM, 1 nmol) inhibited referred, abdominal allodynia evoked by an intracolonic capsaicin injection. BUM was effective when injected IT either before or up to 4 hrs after the establishment of referred allodynia. The TRPV1 antagonist AMG 9810 (1 nmol) also inhibited referred allodynia in this model suggesting the involvement of an endogenous TRPV1 agonist in the dorsal horn in referred allodynia. In support of this suggestion, the endovanilloid TRPV1 agonist, narachidonoyl- dopamine (NADA, 1 or 10 nmol, IT) evoked stroking allodynia in the hindpaw that was blocked by co-treatment with AMG 9810 (1 nmol). The TRPV1-dependent stroking allodynia caused by NADA appeared to be functionally linked to NKCC1 because BUM (1 nmol) also inhibited NADA-evoked stroking allodynia.

Conclusion:

Our findings indicate that spinal NKCC1 and TRPV1 are critical for referred allodynia mediated by a painful visceral stimulus. Moreover, they suggest that endogenous TRPV1 agonists, released in the CNS in painful conditions, might stimulate TRPV1 receptors on primary afferents that, in turn, play a role in increasing NKCC1 activity leading to allodynia.
Discrete tubular supports on pressure vessels
Authors: Kitching R , Olsen B E
Published: June 2007

An experimental stress analysis has been carried out on three tubular supports welded to the lower hemispherical dome of a cylindrical vessel having its axis vertical and being subjected to vertical loads. A procedure (based an a method previously used for webbed brackets) for calculating shell stresses in the vicinity of the supports was examined and was found to be reliable.
High-strain low-endurance fatigue behaviour of B.S.968-steel beams in reversed bending
Authors: Threlfall B D
Published: June 2007

Experiments in repeated reversed plastic bending on beams of high-yield steel to B.S. 968 are reported; the results are compared with similar previous work on beams of mild steel to B.S. 15. General similarity is noted, but an appreciably shorter life is found for high-yield-steel beams under similar proportions of their full plastic moments.
Thermo-elastic analysis of rectangular plates in plane stress by the finite-element displacement method
Authors: Webber J P H
Published: June 2007

The finite-element displacement method is used to solve a number of thermo-elastic plate problems involving different boundary conditions and variations of thickness. A plane-stress element stiffness matrix and temperature-load column matrix are derived on the assumption that thickness and temperature representations within the element are based on corner-point values. Results obtained from different element models are compared with other analytical solutions in order to establish the best element representation.
Vibration of plate and shell structures using triangular finite elements
Authors: Dungar R , Severn R T , Taylor P R
Published: June 2007

Mass and stiffness matrices are obtained for a general-triangle element and for a right-angled-triangle element. Both bending and in-plane actions are considered, although no coupling is assumed, and the matrices relating to bending actions are obtained independently of those relating to in-plane actions. Coupling is introduced, unless all the elements lie in a single plane, when the transformation from local to global co-ordinates is made.

In deriving the stiffness matrices assumptions have been made about the form of the stress components within, and on the boundaries of, the element, together with assumptions about the form of the displacement components on the boundary of the element only. The commonly made assumptions in the derivation of stiffness matrices relate to the form of the displacement components not only on the boundary but throughout the element.

In order to derive satisfactory mass matrices it is necessary to assume the form of the displacement components throughout the element. For the right-angled-triangle mass matrices these displacement components have been assumed independently of the assumed boundary displacements needed for the stiffness matrix. For the general-triangle mass matrix, however, the displacements throughout the element have been made consistent with the boundary displacements which were needed for the stiffness matrix.

Numerical results are given for the first few natural frequencies of a square simply supported slab and a square encastré slab. Comparison with accepted values shows that the finite-element values are accurate, and convergent as the element size is reduced. For the same number of elements it is indicated that general triangles give a more accurate solution than right-angled triangles, probably because of the more satisfactory derivation of the mass matrix for the general triangle. This advantage is offset, however, by the greater computation time required by general triangles.

Calculated and experimental frequency values are also given for a single-curvature arch dam of constant thickness. Mode shapes are not given in any of the numerical solutions although they are produced as an integral part of the computer programme.
Anisotropy of yarn wound on a flanged tube
Authors: Beddoe B
Published: June 2007

Some synthetic fibres possess considerable transverse anisotropy. When yarn made from such fibres is wound under tension on a tube, the pack of wound yarn exhibits a high degree of anisotropy of the cylindrical type. A simple experiment which demonstrates this property is described.

Treating the yarn as elastic and anisotropic, a theory of winding yarn under tension is developed to determine the stresses within the wound yarn. Expressions for the axial strain and the end load of the containing flanged tube are also obtained. Computed results show the dependence of stress distribution on the degree of anisotropy; of particular interest is the large variation of circumferential tension of the yarn, which affects subsequent yarn processing.
Stresses in a composite material with a single broken fibre
Authors: Iremonger M J , Wood W G
Published: June 2007

An investigation has been made into the suitability of the finite-element method for studying the stresses in composite materials and the case of a single broken fibre in a matrix has been examined. It has been found that high stress concentrations occur in the region of the fibre break which increase with decreasing end gap and would cause matrix yielding or fracture at comparatively low overall stresses. When the end gap is not void but filled with matrix much lower stress concentrations occur which, below a certain value of end gap, actually decrease as the gap is made smaller.