510 research outputs found
Strings in five-dimensional anti-de Sitter space with a symmetry
The equation of motion of an extended object in spacetime reduces to an
ordinary differential equation in the presence of symmetry. By properly
defining of the symmetry with notion of cohomogeneity, we discuss the method
for classifying all these extended objects. We carry out the classification for
the strings in the five-dimensional anti-de Sitter space by the effective use
of the local isomorphism between \SO(4,2) and \SU(2,2). We present a
general method for solving the trajectory of the Nambu-Goto string and apply to
a case obtained by the classification, thereby find a new solution which has
properties unique to odd-dimensional anti-de Sitter spaces. The geometry of the
solution is analized and found to be a timelike helicoid-like surface
Evaluation of portable water in five provinces of Zambia using a water pollution index
Five provinces with different environmental characteristics were evaluated for water pollution with the aim of identifying the major sources and area(s) most affected. The results indicate that the water in Lusaka Province is significantly high in nitrate and sodium concentration compared to other provinces considered in this study. The results further reveal that ground water is most affected by nitrate and sodium. On the contrary, dissolved organic carbon (DOC) was found to be significantly higher in surface water but no particular province registered a higher amount compared to others. The results further reveal that the pollution is primarily a function of human activities, social amenities and industrial activities in the study areas.Key words: Nitrate, sulphate, groundwater, Lusaka, ion exchange/cation-exchange chromatography
Families of Roles: A new theory of occurrent-dependent roles
PublishedRoles are important both theoretically and practically for modelling the world around us. Although many theories of roles have been proposed, there remain aspects which are little understood. In this paper we investigate roles and their contexts from a temporal point of view.We introduce the idea of a family of occurrent-dependent roles as a means to organise prospective and retrospective derived roles around an original role from which they are derived. By this means we account for the existence of groups of similar roles which are difficult to distinguish without a careful analysis of the temporal aspects. Following detailed informal discussion, we present a preliminary formalisation of the key concepts and relations.Air Force Research Laborator
An anatomic study of the accessory anterolateral talar facet
Background: A small accessory facet with articular surface morphology is occasionally seen on the talus, bordering on the lateral end of the sinus tarsi. This facet has been named the accessory anterolateral talar facet. However, few anatomical studies have addressed this facet. Here we present the precise morphology of accessory anterolateral talar facet with emphasis on anatomical correlation between the presence of this facet and the angle of the infero-lateral surface of the talus (talar infero-lateral surface — TILS angle). Materials and methods: A total of 22 (11 male, 11 female) adult cadavers with no known pathological conditions in the talocalcaneal joints were examined during educational dissection at Nagoya City University Medical School in 2013. After exclusion of 1 joint due to the poor condition of the talus, 43 talus (22 right, 21 left) were analysed. We judged the presence of the accessory anterolateral talar facet and measured TILS angle. We performed statistical analysis on the point of laterality, gender difference and the difference in the TILS angles in tali with or without the accessory anterolateral talar facets. Results: An accessory anterolateral talar facet was identified in 11 (26%) of the 43 specimens. Of the 21 cadavers with paired talar specimens, 5 displayed the facet bilaterally. Conclusions: There was no sex difference and no significant laterality, however we found that TILS angle was significantly larger in accessory anterolateral talar facet positive samples than in negative ones
Intracellular MMP3 Promotes HSP Gene Expression in Collaboration With Chromobox Proteins
Matrix metalloproteinases (MMPs) are crucial factors in tumor progression, inflammatory/immune responses and tissue development/regeneration. Of note, it has been known that MMPs promote genome instability, epithelial-mesenchymal transition, invasion, and metastasis in tumor progression. We previously reported that human MMP3 could translocate into cellular nuclei and control transcription in human chondrosarcoma-derived cells and in articular cartilage (Eguchi et al. [2008] Mol Cell Biol 28(7):2391-2413); however, further transcriptional target genes and cofactors of intranuclear MMP3 have not been uncovered. In this paper, we used transcriptomics analysis in order to examine novel transcriptional target genes regulated by intracellular MMP3. We found that mRNA levels of HSP family members (HSP70B', HSP72, HSP40/DNAJ, and HSP20/CRYAB) are upregulated by the intracellular MMP3 overload. Bioinformatic analysis predicted several transcription factors that possibly interact with MMP3. Among these factors, heat shock factor 1 (HSF1) cooperated with the MMP3 to activate the HSP70B' gene promoter in reporter gene assays, while a dominant negative HSF1 blocked the role for MMP3 in the trans-activation. The hemopexin-like repeat (PEX) domain of the human MMP3 was essential for transcriptional induction of the HSP70B' gene. In addition, chromobox proteins CBX5/HP1α and CBX3/HP1γ cooperated with the PEX domain in induction of HSP70B' mRNA. Taken together, this study newly clarified that intracellular MMP3 cooperate with CBXs/HP1s in transcriptional promotion of HSP genes
The maize INDETERMINATE1 flowering time regulator defines a highly conserved zinc finger protein family in higher plants
BACKGROUND: The maize INDETERMINATE1 gene, ID1, is a key regulator of the transition to flowering and the founding member of a transcription factor gene family that encodes a protein with a distinct arrangement of zinc finger motifs. The zinc fingers and surrounding sequence make up the signature ID domain (IDD), which appears to be found in all higher plant genomes. The presence of zinc finger domains and previous biochemical studies showing that ID1 binds to DNA suggests that members of this gene family are involved in transcriptional regulation. RESULTS: Comparison of IDD genes identified in Arabidopsis and rice genomes, and all IDD genes discovered in maize EST and genomic databases, suggest that ID1 is a unique member of this gene family. High levels of sequence similarity amongst all IDD genes from maize, rice and Arabidopsis suggest that they are derived from a common ancestor. Several unique features of ID1 suggest that it is a divergent member of the maize IDD family. Although no clear ID1 ortholog was identified in the Arabidopsis genome, highly similar genes that encode proteins with identity extending beyond the ID domain were isolated from rice and sorghum. Phylogenetic comparisons show that these putative orthologs, along with maize ID1, form a group separate from other IDD genes. In contrast to ID1 mRNA, which is detected exclusively in immature leaves, several maize IDD genes showed a broad range of expression in various tissues. Further, Western analysis with an antibody that cross-reacts with ID1 protein and potential orthologs from rice and sorghum shows that all three proteins are detected in immature leaves only. CONCLUSION: Comparative genomic analysis shows that the IDD zinc finger family is highly conserved among both monocots and dicots. The leaf-specific ID1 expression pattern distinguishes it from other maize IDD genes examined. A similar leaf-specific localization pattern was observed for the putative ID1 protein orthologs from rice and sorghum. These similarities between ID1 and closely related genes in other grasses point to possible similarities in function
Bilirubin as an Anti-oxidant for Surgical Stress: A Preliminary Report of Bilirubin Oxidative Metabolites
Background Bilirubin has been recognized as an antioxidant.
The purpose of this study was to examine
whether bilirubin would act as an antioxidant for
surgical stress in humans. Materials and Methods
Serum bilirubin and urinary bilirubin oxidative
metabolites (BOM) were measured in 96 patients
who underwent surgery. The antioxidant activity
of bilirubin was assessed using BOM measured
by enzyme-linked immunosorbent assay with an
anti-bilirubin monoclonal antibody. Results Serum
bilirubin levels increased after surgery in all 96
patients (p<0.01), but did not correlate with operation
time or blood loss (p=0.53 and p=0.28, respectively).
BOM increased only in patients with major
surgeries (p=0.048). Significant correlations between
BOM and operation time and blood loss were found
(p<0.01). Conclusions Bilirubin appears to act as an
antioxidant for invasive surgery in humans. Urinary
BOM could be a reliable marker for the degree of
surgical stress
Volume Expansion of Swiss-Cheese Universe
In order to investigate the effect of inhomogeneities on the volume expansion
of the universe, we study modified Swiss-Cheese universe model. Since this
model is an exact solution of Einstein equations, we can get an insight into
non-linear dynamics of inhomogeneous universe from it. We find that
inhomogeneities make the volume expansion slower than that of the background
Einstein-de Sitter universe when those can be regarded as small fluctuations in
the background universe. This result is consistent with the previous studies
based on the second order perturbation analysis. On the other hand, if the
inhomogeneities can not be treated as small perturbations, the volume expansion
of the universe depends on the type of fluctuations. Although the volume
expansion rate approaches to the background value asymptotically, the volume
itself can be finally arbitrarily smaller than the background one and can be
larger than that of the background but there is an upper bound on it.Comment: 22 pages, 7 figures, to be submitted to Phys. Rev.
- …