bluuebunny/crossref_metadata_2025 huggingface dataset:
Online Identification of Linear Time-varying Stiffness of Structural Systems by Wavelet Analysis
Authors: Basu Biswajit , Nagarajaiah Satish , Chakraborty Arunasis
Published: February 2008

An online identification of variation of stiffness in structural systems has been presented in this study. The proposed technique is based on wavelet analysis. The time-frequency characteristics of the wavelets have been used in the formulation of online identification. The basis function used is a modified version of the Littlewood—Paley wavelet. The bases generated from this wavelet at different scales have the advantage of non-overlapping frequency bands which has been utilized in the frequency tracking algorithm. Further, an algorithm for detection of variation in modes shapes in time-varying linear multi-degree-of-freedom (MDOF) systems has been developed. Several types of changes in stiffness, such as a sudden jump, a ramp (gradual) change, or a sudden change with subsequent restoration of stiffness have been considered as illustrative eXamples in case of single-degree-of-freedom (SDOF) and MDOF systems. It has been found that the proposed technique for wavelet based online identification is efficient in tracking different types of cases considered and has potential for application in adaptive control.
A Structural Neural System for Real-time Health Monitoring of Composite Materials
Authors: Kirikera Goutham R. , Shinde Vishal , Schulz Mark J. , Ghoshal Anindya , Sundaresan Mannur J. , Allemang Randall J. , Jong Won Lee
Published: February 2008

A prototype structural neural system (SNS) is tested for the first time and damage detection results are presented in this study. The SNS is a passive online structural health monitoring (SHM) system that mimics the synaptic parallel computation networks present in the human biological neural system. Piezoelectric ceramic sensors and analog electronics are used to form neurons that measure strain waves generated by damage. The sensing of strain waves is similar to the proven nondestructive evaluation (NDE) technique of acoustic emission (AE) monitoring. Fatigue testing of a composite specimen on a four-point bending fiXture is performed, and the SNS is used to monitor the specimen for damage in real time. The prototype SNS used four sensors as inputs, but the number of inputs can be in the tens or hundreds depending on the type of SNS processor used. This is an area of continuing development. The SNS has two channels of signal output that are digitized and processed in a computer. The first output channel tracks the propagation of waves due to damage, and the second output channel provides the combined AE responses of the sensors. The data from these two channels are used to predict the location of damage and to qualitatively indicate the severity of the damage. Overall, this study shows that the SNS can detect damage growth in composites during operation of the structure, and the SNS architecture has the potential to tremendously simplify the AE technique for use in on-board SHM. Ten or more input neurons can be used, and still only two output channels are needed. Two levels of monitoring are possible using the SNS; a coarser SHM approach, or an on-board NDE approach. The SHM approach uses the SNS with a coarse grid of neurons to monitor and detect damage occurring in a general area during operation of the structure. The SNS will indicate where and when a more sensitive inspection is needed which can be done using ground-based NDE techniques. The on-board NDE approach uses the SNS with a fine coverage of neurons for highly sensitive NDE which continuously listens for damage and provides real-time processing and information about any damage in the structure and the performance limits and safety of the vehicle.
An Optical Fiber Sensor System for Remote Displacement Monitoring of Structures — Prototype Tests in the Laboratory
Authors: Metje N. , Chapman D.N. , Rogers C.D.F. , Henderson P. , Beth M.
Published: February 2008

This study describes a new optical fiber monitoring system to measure structural displacements. The underlying concept is based on a square fiberglass `Smart Rod' containing grooves in each face, glued into which are optical fibers containing fiber Bragg gratings (FBGs) at a succession of points along their length. The Smart Rod is rigidly fiXed at discrete points to the structure being assessed and the strain at each FBG is determined optically. The strain is thereafter converted to structural displacements. This study describes a series of `bench test' laboratory eXperiments designed to eXplore the challenges of installing the monitoring system and interpreting the results. The results from the tests are presented and discussed in the conteXt of the accuracy achievable with the proposed system. The tests have shown that the Smart Rod is sensitive enough to measure rotational movements of 0.5° and lateral movements of 0.1 mm of the fiXings in the laboratory. Recommendations are consequently made for a practical instrumentation system based upon the Smart Rod. An eXample is provided showing the Smart Rod installed in a road tunnel to monitor displacements of the tunnel lining.
Structural Health Monitoring and Damage Prognosis in Fatigue
Authors: Kulkarni S.S. , Achenbach J.D.
Published: February 2008

A conceptual structural health monitoring (SHM) system to monitor fatigue damage is discussed in this study. The first part of the study is concerned with damage prognosis. A methodology to use the data from a pre-crack damage monitoring system to predict the number of cycles to macrocrack-initiation in a probabilistic sense, is presented. Issues related to quantifying damage, a damage evolution law, and numerical evaluation of the probability of macrocrack initiation are discussed. The second part of the study deals with quantifying the effects of imperfect inspections during the growth of a macrocrack. The probability that there eXists an undetected critical crack is the quantity of interest. An analytical eXpression for this quantity is derived for the case of a two-dimensional crack. A Monte Carlo simulation method to quantify the effects of imperfect inspections is also presented. Numerical results are presented for two eXamples of surface-breaking cracks with different geometries.
Emancipation or workability?
Authors: Johansson Anders W. , Lindhult Erik
Published: February 2008

In this article a distinction between a pragmatic and a critical orientation of action research is made. These orientations can be considered, implicitly or explicitly, to be the main alternatives in AR today. What are the assumptions behind, and practical implications for, AR projects with different orientations? A number of themes are introduced where a tension between the two are identified and illustrated in the form of a dialogue and friendly quarrel between proponents from each side. It is argued that the two orientations suit different research contexts and cannot easily be combined. The pragmatic orientation is well suited for contexts where concerted and immediate action is needed, whereas the critical is preferable where transformative action needs to be preceded by critical thinking and reflection. In the former, power to act is a desired outcome, and in the latter, unequal and invisible power relations need to be unveiled before they can be transformed. The responsibility of the researcher, as well as the form of knowledge developed, differs between the two orientations.
Participatory teacher development at schools
Authors: Koutselini Mary
Published: February 2008

This article describes an action research study on reflective development at school and discusses methodological and pedagogical issues arising from teacher beliefs and expectations. Teachers and researchers participated in four cooperative cycles of inquiry, where situated learning and reflection supported their conceptual change and meaning-making. Teachers underwent a gradual shift from imposed, predefined teaching and learning to reflective collaboration and response to different needs of different students, while researchers gained a contextualized understanding of teachers' attitudes and beliefs about teaching and learning and examined their own and the teachers' roles as action researchers. Issues related to school ethos, teachers' defensive attitudes and trust-building among teachers are discussed in light of the reflective paradigm of participants' development.
Challenging institutional barriers to community-based research
Authors: Stoecker Randy
Published: February 2008

Those of us attempting to develop truly equal partnerships with communities and community organizations, using the method of community-based research, encounter many barriers. These barriers revolve around who sets the schedule, who determines the labor pool, who controls the product, and who gets the funding. In this article, a case study shows how those barriers exert themselves, and evaluates the success of strategies to challenge those barriers. It ends with a set of recommendations for changing university overhead policies, developing university quality control practices, refining the university IRB process, institutionalizing a flash seminar structure, and training community members to control the research relationship.
The role of citizen participation and action research principles in Main Street revitalization
Authors: Silverman Robert Mark , Taylor Henry L. , Crawford Christopher
Published: February 2008

This article examines the use of citizen participation techniques during the planning process for neighborhood revitalization in the Village of Depew which is an industrial suburb of Buffalo, New York. The article focuses on how action research principles can inform and enhance traditional approaches to citizen participation. In particular, we discuss our role as university-based consultants in the local planning process and how drawing from action research principles helped us remain focused on advocating for broad-based citizen participation. Our analysis was based on the application of action research principles and participant observation techniques. During the time that each of us was involved in the planning process for Depew's neighborhood revitalization, reflexive field notes and other data were collected. The article critiques how citizen participation was used to plan for neighborhood revitalization in Depew, and discusses the degree to which action research principles can be applied to future citizen participation efforts.
Fatigue Versus Activity-Dependent Fatigability in Patients With Central or Peripheral Motor Impairments
Authors: Dobkin Bruce H.
Published: February 2008

In the rehabilitation literature, fatigue is a common symptom of patients with any neurological impairment when defined as a subjective lack of physical and mental energy that interferes with usual activities. Some complaints may, however, arise from fatigability , an objective decline in strength as routine use of muscle groups proceeds. By this refined definition of fatigue, exercise or sustained use reduces the ability of muscles to produce force or power, regardless of whether the task can be sustained. Fatigability may be masked clinically because (1) the degree of weakening is not profound, (2) activity-induced weakness rapidly lessens with cessation of exertion, and (3) clinicians rarely test for changes in strength after repetitive movements to objectively entertain the diagnosis. The repetitive movements that induce fatigability during daily activities are an iterative physiological process that depends on changing states induced by activation of spared central and peripheral neurons and axons and compromised muscle. Fatigability may be especially difficult to localize in patients undergoing neurorehabilitation, in part because no finite boundary exists between the central and peripheral components of motor reserve and endurance. At the bedside, however, manual muscle testing before and after repetitive movements could at least put some focus on the presence of fatigability in any patient with motor impairments and related disabilities. Reliable measures of fatigability beyond a careful clinical examination, such as physiological changes monitored by cerebral functional neuroimaging techniques and more standardized central and peripheral electrical and magnetic stimulation paradigms, may help determine the mechanisms of activity-dependent weakening and lead to specific therapies. Testable interventions to increase motor reserve include muscle strengthening and endurance exercises, varying the biomechanical requirements of repetitive muscle contractions, and training-induced neural plasticity or pharmacologic manipulations to enhance synaptic efficacy.
Structural investigations into the interaction of hemoglobin and part structures with bacterial endotoxins
Authors: Howe Jörg , Garidel Patrick , Roessle Manfred , Richter Walter , Alexander Christian , Fournier Karin , Mach Jean Pierre , Waelli Thierry , Gorczynski Reginald M. , Ulmer Artur J. , Zähringer Ulrich , Hartmann Alfred , Rietschel Ernst Th. , Brandenburg Klaus
Published: February 2008

An understanding of details of the interaction mechanisms of bacterial endotoxins (lipopolysaccharide, LPS) with the oxygen transport protein hemoglobin is still lacking, despite its high biological relevance. Here, a biophysical investigation into the endotoxin:hemoglobin interaction is presented which comprises the use of various rough mutant LPS as well as free lipid A; in addition to the complete hemoglobin molecule from fetal sheep extract, also the partial structure α-chain and the heme-free sample are studied. The investigations comprise the determination of the gel-to-liquid crystalline phase behaviour of the acyl chains of LPS, the ultrastructure (type of aggregate structure and morphology) of the endotoxins, and the incorporation of the hemoglobins into artificial immune cell membranes and into LPS. Our data suggest a model for the interaction between Hb and LPS in which hemoglobins do not react strongly with the hydrophilic or with the hydrophobic moiety of LPS, but with the complete endotoxin aggregate. Hb is able to incorporate into LPS with the longitudinal direction parallel to the lipid A double-layer. Although this does not lead to a strong disturbance of the LPS acyl chain packing, the change of the curvature leads to a slightly conical molecular shape with a change of the three-dimensional arrangement from unilamellar into cubic LPS aggregates. Our previous results show that cubic LPS structures exhibit strong endotoxic activity. The property of Hb on the physical state of LPS described here may explain the observation of an increase in LPS-mediating endotoxicity due to the action of Hb.
PDTD: a web-accessible protein database for drug target identification
Authors: Gao Zhenting , Li Honglin , Zhang Hailei , Liu Xiaofeng , Kang Ling , Luo Xiaomin , Zhu Weiliang , Chen Kaixian , Wang Xicheng , Jiang Hualiang
Published: February 2008

Background

Target identification is important for modern drug discovery. With the advances in the development of molecular docking, potential binding proteins may be discovered by docking a small molecule to a repository of proteins with three-dimensional (3D) structures. To complete this task, a reverse docking program and a drug target database with 3D structures are necessary. To this end, we have developed a web server tool, TarFisDock (Tar get Fis hing Dock ing) http://www.dddc.ac.cn/tarfisdock, which has been used widely by others. Recently, we have constructed a protein target database, P otential D rug T arget D atabase (PDTD), and have integrated PDTD with TarFisDock. This combination aims to assist target identification and validation.

Description

PDTD is a web-accessible protein database for in silico target identification. It currently contains >1100 protein entries with 3D structures presented in the Protein Data Bank. The data are extracted from the literatures and several online databases such as TTD, DrugBank and Thomson Pharma. The database covers diverse information of >830 known or potential drug targets, including protein and active sites structures in both PDB and mol2 formats, related diseases, biological functions as well as associated regulating (signaling) pathways. Each target is categorized by both nosology and biochemical function. PDTD supports keyword search function, such as PDB ID, target name, and disease name. Data set generated by PDTD can be viewed with the plug-in of molecular visualization tools and also can be downloaded freely. Remarkably, PDTD is specially designed for target identification. In conjunction with TarFisDock, PDTD can be used to identify binding proteins for small molecules. The results can be downloaded in the form of mol2 file with the binding pose of the probe compound and a list of potential binding targets according to their ranking scores.

Conclusion

PDTD serves as a comprehensive and unique repository of drug targets. Integrated with TarFisDock, PDTD is a useful resource to identify binding proteins for active compounds or existing drugs. Its potential applications include in silico drug target identification, virtual screening, and the discovery of the secondary effects of an old drug (i.e. new pharmacological usage) or an existing target (i.e. new pharmacological or toxic relevance), thus it may be a valuable platform for the pharmaceutical researchers. PDTD is available online at http://www.dddc.ac.cn/pdtd/.
Evolutionary Pareto-optimization of stably folding peptides
Authors: Gronwald Wolfram , Hohm Tim , Hoffmann Daniel
Published: February 2008

Background

As a rule, peptides are more flexible and unstructured than proteins with their substantial stabilizing hydrophobic cores. Nevertheless, a few stably folding peptides have been discovered. This raises the question whether there may be more such peptides that are unknown as yet. These molecules could be helpful in basic research and medicine.

Results

As a method to explore the space of conformationally stable peptides, we have developed an evolutionary algorithm that allows optimization of sequences with respect to several criteria simultaneously, for instance stability, accessibility of arbitrary parts of the peptide, etc. In a proof-of-concept experiment we have perturbed the sequence of the peptide Villin Headpiece, known to be stable in vitro. Starting from the perturbed sequence we applied our algorithm to optimize peptide stability and accessibility of a loop. Unexpectedly, two clusters of sequences were generated in this way that, according to our criteria, should form structures with higher stability than the wild-type. The structures in one of the clusters possess a fold that markedly differs from the native fold of Villin Headpiece. One of the mutants predicted to be stable was selected for synthesis, its molecular 3D-structure was characterized by nuclear magnetic resonance spectroscopy, and its stability was measured by circular dichroism. Predicted structure and stability were in good agreement with experiment. Eight other sequences and structures, including five with a non-native fold are provided as bona fide predictions.

Conclusion

The results suggest that much more conformationally stable peptides may exist than are known so far, and that small fold classes could comprise well-separated sub-folds.
Epigenetic inheritance based evolution of antibiotic resistance in bacteria
Authors: Adam Mike , Murali Bhuvana , Glenn Nicole O , Potter S Steven
Published: February 2008

Background

The evolution of antibiotic resistance in bacteria is a topic of major medical importance. Evolution is the result of natural selection acting on variant phenotypes. Both the rigid base sequence of DNA and the more plastic expression patterns of the genes present define phenotype.

Results

We investigated the evolution of resistant E. coli when exposed to low concentrations of antibiotic. We show that within an isogenic population there are heritable variations in gene expression patterns, providing phenotypic diversity for antibiotic selection to act on. We studied resistance to three different antibiotics, ampicillin, tetracycline and nalidixic acid, which act by inhibiting cell wall synthesis, protein synthesis and DNA synthesis, respectively. In each case survival rates were too high to be accounted for by spontaneous DNA mutation. In addition, resistance levels could be ramped higher by successive exposures to increasing antibiotic concentrations. Furthermore, reversion rates to antibiotic sensitivity were extremely high, generally over 50%, consistent with an epigenetic inheritance mode of resistance. The gene expression patterns of the antibiotic resistant E. coli were characterized with microarrays. Candidate genes, whose altered expression might confer survival, were tested by driving constitutive overexpression and determining antibiotic resistance. Three categories of resistance genes were identified. The endogenous β-lactamase gene represented a cryptic gene, normally inactive, but when by chance expressed capable of providing potent ampicillin resistance. The glutamate decarboxylase gene, in contrast, is normally expressed, but when overexpressed has the incidental capacity to give an increase in ampicillin resistance. And the DAM methylase gene is capable of regulating the expression of other genes, including multidrug efflux pumps.

Conclusion

In this report we describe the evolution of antibiotic resistance in bacteria mediated by the epigenetic inheritance of variant gene expression patterns. This provides proof in principle that epigenetic inheritance, as well as DNA mutation, can drive evolution.
Genomic organization and recombinational unit duplication-driven evolution of ovine and bovine T cell receptor gamma loci
Authors: Vaccarelli Giovanna , Miccoli Maria C , Antonacci Rachele , Pesole Graziano , Ciccarese Salvatrice
Published: February 2008

Background

In humans and mice ("γδ low species") less than 5% of the peripheral blood T lymphocytes are gamma/delta T cells, whereas in chicken and artiodactyls ("γδ high species") gamma/delta T cells represent about half of the T cells in peripheral blood. In cattle and sheep (Bovidae) two paralogous T cell receptor gamma loci (TRG1 and TRG2) have been found. TRG1 is located on 4q3.1, within a region of homology with the human TRG locus on chromosome 7, while TRG2 localizes on 4q2.2 and appears to be unique to ruminants. The purpose of this study was the sequencing of the genomic regions encompassing both loci in a "γδ high" organism and the analysis of their evolutionary history.

Results

We obtained the contiguous genomic sequences of the complete sheep TRG1 and TRG2 loci gene repertoire and we performed cattle/sheep sequence analysis comparison using data available through public databases. Dot plot similarity matrix comparing the two sheep loci with each other has shown that variable (V), joining (J) and constant (C) genes have evolved through a series of duplication events involving either entire cassettes, each containing the basic V-J-J-C recombinational unit, or single V genes. The phylogenetic behaviour of the eight enhancer-like elements found in the sheep, compared with the single copy present in the human TRG locus, and evidence from concordant insertions of repetitive elements in all analyzed TRGJ blocks allowed us to infer an evolutionary scenario which highlights the genetic "flexibility" of this region and the duplication-driven evolution of gene cassettes. The strong similarity of the human and Bovidae intergenic J-J-C regions, which display an enhancer-like element at their 3' ends, further supports their key role in duplications.

Conclusion

We propose that only duplications of entire J-J-C regions that possessed an enhancer-like element at their 3' end, and acquired at least one V segment at their 5' end, were selected and fixed as functional recombinational units.
Molecular characterization, tissue expression and sequence variability of the barramundi (Lates calcarifer) myostatin gene
Authors: De Santis Christian , Evans Brad S , Smith-Keune Carolyn , Jerry Dean R
Published: February 2008

Background

Myostatin (MSTN) is a member of the transforming growth factor-β superfamily that negatively regulates growth of skeletal muscle tissue. The gene encoding for the MSTN peptide is a consolidate candidate for the enhancement of productivity in terrestrial livestock. This gene potentially represents an important target for growth improvement of cultured finfish.

Results

Here we report molecular characterization, tissue expression and sequence variability of the barramundi (Lates calcarifer) MSTN-1 gene. The barramundi MSTN-1 was encoded by three exons 379, 371 and 381 bp in length and translated into a 376-amino acid peptide. Intron 1 and 2 were 412 and 819 bp in length and presented typical GT...AG splicing sites. The upstream region contained cis-regulatory elements such as TATA-box and E-boxes. A first assessment of sequence variability suggested that higher mutation rates are found in the 5' flanking region with several SNP's present in this species. A putative micro RNA target site has also been observed in the 3'UTR (untranslated region) and is highly conserved across teleost fish. The deduced amino acid sequence was conserved across vertebrates and exhibited characteristic conserved putative functional residues including a cleavage motif of proteolysis (RXXR), nine cysteines and two glycosilation sites. A qualitative analysis of the barramundi MSTN-1 expression pattern revealed that, in adult fish, transcripts are differentially expressed in various tissues other than skeletal muscles including gill, heart, kidney, intestine, liver, spleen, eye, gonad and brain.

Conclusion

Our findings provide valuable insights such as sequence variation and genomic information which will aid the further investigation of the barramundi MSTN-1 gene in association with growth. The finding for the first time in finfish MSTN of a miRNA target site in the 3'UTR provides an opportunity for the identification of regulatory mutations on the expression of this gene.
Circadian regulation of a limited set of conserved microRNAs in Drosophila
Authors: Yang Maocheng , Lee Jung-Eun , Padgett Richard W , Edery Isaac
Published: February 2008

Background

MicroRNAs (miRNAs) are short non-coding RNA molecules that target mRNAs to control gene expression by attenuating the translational efficiency and stability of transcripts. They are found in a wide variety of organisms, from plants to insects and humans. Here, we use Drosophila to investigate the possibility that circadian clocks regulate the expression of miRNAs.

Results

We used a microarray platform to survey the daily levels of D. melanogaster miRNAs in adult heads of wildtype flies and the arrhythmic clock mutant cyc
01. We find two miRNAs (dme-miR-263a and -263b) that exhibit robust daily changes in abundance in wildtype flies that are abolished in the cyc
01 mutant. dme-miR-263a and -263b reach trough levels during the daytime, peak during the night and their levels are constitutively elevated in cyc
01 flies. A similar pattern of cycling is also observed in complete darkness, further supporting circadian regulation. In addition, we identified several miRNAs that appear to be constitutively expressed but nevertheless differ in overall daily levels between control and cyc
01 flies.

Conclusion

The circadian clock regulates miRNA expression in Drosophila, although this appears to be highly restricted to a small number of miRNAs. A common mechanism likely underlies daily changes in the levels of dme-miR-263a and -263b. Our results suggest that cycling miRNAs contribute to daily changes in mRNA and/or protein levels in Drosophila. Intriguingly, the mature forms of dme-miR-263a and -263b are very similar in sequence to several miRNAs recently shown to be under circadian regulation in the mouse retina, suggesting conserved functions.
Secreted factors from olfactory mucosa cells expanded as free-floating spheres increase neurogenesis in olfactory bulb neurosphere cultures
Authors: Barraud Perrine , He Xiaoling , Caldwell Maeve A , Franklin Robin JM
Published: February 2008

Background

The olfactory epithelium is a neurogenic tissue comprising a population of olfactory receptor neurons that are renewed throughout adulthood by a population of stem and progenitor cells. Because of their relative accessibility compared to intra-cranially located neural stem/progenitor cells, olfactory epithelium stem and progenitor cells make attractive candidates for autologous cell-based therapy. However, olfactory stem and progenitor cells expand very slowly when grown as free-floating spheres (olfactory-spheres) under growth factor stimulation in a neurosphere assay.

Results

In order to address whether olfactory mucosa cells extrinsically regulate proliferation and/or differentiation of immature neural cells, we cultured neural progenitor cells derived from mouse neonatal olfactory bulb or subventricular zone (SVZ) in the presence of medium conditioned by olfactory mucosa-derived spheres (olfactory-spheres). Our data demonstrated that olfactory mucosa cells produced soluble factors that affect bulbar neural progenitor cell differentiation but not their proliferation when compared to control media. In addition, olfactory mucosa derived soluble factors increased neurogenesis, especially favouring the generation of non-GABAergic neurons. Olfactory mucosa conditioned medium also contained several factors with neurotrophic/neuroprotective properties. Olfactory-sphere conditioned medium did not affect proliferation or differentiation of SVZ-derived neural progenitors.

Conclusion

These data suggest that the olfactory mucosa does not contain factors that are inhibitory to neural stem/progenitor cell proliferation but does contain factors that steer differentiation toward neuronal phenotypes. Moreover, they suggest that the poor expansion of olfactory-spheres may be in part due to intrinsic properties of the olfactory epithelial stem/progenitor cell population.
Effect of Lactobacillus acidophilus supernatants on body weight and leptin expression in rats
Authors: Sousa Renato , Halper Jaroslava , Zhang Jian , Lewis Stephen J , Li Wan-I O
Published: February 2008

Background

Lactobacillus extracts and supernatants have been used as probiotics in human and veterinary medicine for their ability to enhance wound healing and immunity. Previous data from our laboratory demonstrated that Lactobacillus supernatant (LS) stimulated wound healing, angiogenesis and proliferation of embryonic cells after topical application. This current study shows that LS after its administration into the cerebral ventricles of male rats exerts systemic effects.

Methods

The right lateral cerebral ventricle of young male rats was accessed through intracerebroventricular cannulation (ICV) under anesthesia and aseptic conditions. One group of control rats received saline solution, a second control group received 0.8 M lactic acid solution (to control for acidity of LS), and a third group received LS. The animals were sacrificed 12, 24, 48, 96 and 120 hours after the injection. Selected tissues were collected, fixed in 10% buffered formalin and used for immunohistochemistry and in situ hybridization. Other tissues were frozen and extracted for immunoblotting

Results

LS-injected animals had a slight decrease in body weight when compared to their initial weight and to both control groups. Using immunohistochemistry and in situ hybridization leptin expression was studied in multiple brain sections and peripheral adipose tissue of control and LS-injected rats. Strong cytoplasmic stain was observed by both techniques in neurons of the cerebral cortex, thalamus, hypothalamus, hippocampus and, to lesser degree, in the cells of the choroid plexus in the LS-injected rats. Control animals demonstrated much less intense staining in neurons located in the same regions using immunohistochemistry and almost no staining with in situ hybridization technique. Adipose tissue exhibited slight presence of leptin in LS-treated animals. In contrast no immunohistochemical staining for GM-CSF and TNFα was observed in brains from control and treated rats. Western blotting showed mild increase in leptin and leptin receptors in intestines and retroperitoneal adipose tissues of LS-injected rats.

Conclusion

This study demonstrates that direct administration of LS into rat CNS leads to a decrease in body weight of rats and an increase in the expression of leptin in specific areas of the brain and retroperitoneal adipose tissue.
Identification of ICF categories relevant for nursing in the situation of acute and early post-acute rehabilitation
Authors: Mueller Martin , Boldt Christine , Grill Eva , Strobl Ralf , Stucki Gerold
Published: February 2008

Background

The recovery of patients after an acute episode of illness or injury depends both on adequate medical treatment and on the early identification of needs for rehabilitation care. The process of early beginning rehabilitation requires efficient communication both between health professionals and the patient in order to effectively address all rehabilitation goals. The currently used nursing taxonomies, however, are not intended for interdisciplinary use and thus may not contribute to efficient rehabilitation management and an optimal patient outcome. The ICF might be the missing link in this communication process. The objective of this study was to identify the categories of the International Classification of Functioning, Disability and Health (ICF) categories relevant for nursing care in the situation of acute and early post-acute rehabilitation.

Methods

First, in a consensus process, "Leistungserfassung in der Pflege" (LEP) nursing interventions relevant for the situation of acute and early post-acute rehabilitation were selected. Second, in an integrated two-step linking process, two nursing experts derived goals of LEP nursing interventions from their practical knowledge and selected corresponding ICF categories most relevant for patients in acute and post-acute rehabilitation (ICF Core Sets).

Results

Eighty-seven percent of ICF Core Set categories could be linked to goals of at least one nursing intervention variable of LEP. The ICF categories most frequently linked with LEP nursing interventions were respiration functions, experience of self and time functions and focusing attention. Thirteen percent of ICF Core Set categories could not be linked with LEP nursing interventions. The LEP nursing interventions which were linked with the highest number of different ICF-categories of all were "therapeutic intervention", "patient-nurse communication/information giving" and "mobilising".

Conclusion

The ICF Core Sets for the acute hospital and early post-acute rehabilitation facilities are highly relevant for rehabilitation nursing. Linking nursing interventions with ICF Core Set categories is a feasible way to analyse nursing. Using the ICF Core Sets to describe goals of nursing interventions both facilitates inter-professional communication and respects patient's needs. The ICF may thus be a useful framework to set nursing intervention goals.
A natural mineral supplement provides relief from knee osteoarthritis symptoms: a randomized controlled pilot trial
Authors: Frestedt Joy L , Walsh Melanie , Kuskowski Michael A , Zenk John L
Published: February 2008

Background

This small, pilot study evaluated the impact of treatment with a natural multi-mineral supplement from seaweed (Aquamin) on walking distance, pain and joint mobility in subjects with moderate to severe osteoarthritis of the knee.

Methods

Subjects (n = 70) with moderate to severe osteoarthritis of the knee were randomized to four double-blinded treatments for 12 weeks: (a) Glucosamine sulfate (1500 mg/d); (b) Aquamin (2400 mg/d); (c) Combined treatment composed of Glucosamine sulfate (1500 mg/d) plus Aquamin (2400 mg/d) and (d) Placebo. Primary outcome measures were WOMAC scores and 6 Minute Walking Distances (6 MWD). Laboratory based blood tests were used as safety measures.

Results

Fifty subjects completed the study and analysis of the data showed significant differences between the groups for changes in WOMAC pain scores over time (p = 0.009 ANCOVA); however, these data must be reviewed with caution since significant differences were found between the groups at baseline for WOMAC pain and stiffness scores (p = 0.0039 and p = 0.013, respectively, ANOVA). Only the Aquamin and Glucosamine groups demonstrated significant improvements in symptoms over the course of the study. The combination group (like the placebo group) did not show any significant improvements in OA symptoms in this trial. Within group analysis demonstrated significant improvements over time on treatment for the WOMAC pain, activity, composite and stiffness (Aquamin only) scores as well as the 6 minute walking distances for subjects in the Aquamin and Glucosamine treatment groups. The Aquamin and Glucosamine groups walked 101 feet (+7%) and 56 feet (+3.5%) extra respectively. All treatments were well tolerated and the adverse events profiles were not significantly different between the groups.

Conclusion

This small preliminary study suggested that a multi mineral supplement (Aquamin) may reduce the pain and stiffness of osteoarthritis of the knee over 12 weeks of treatment and warrants further study.

Trial registration

ClinicalTrials.gov number: NCT00452101.
Does CD4+CD25+foxp3+ cell (Treg) and IL-10 profile determine susceptibility to immune reconstitution inflammatory syndrome (IRIS) in HIV disease?
Authors: Shankar Esaki Muthu , Vignesh Ramachandran , Velu Vijayakumar , Murugavel Kailapuri G , Sekar Ramalingam , Balakrishnan Pachamuthu , Lloyd Charmaine AC , Saravanan Shanmugam , Solomon Suniti , Kumarasamy Nagalingeswaran
Published: February 2008

HIV-specific T-lymphocyte responses that underlie IRIS are incomplete and largely remain hypothetical. Of the several mechanisms presented by the host to control host immunological damage, Treg cells are believed to play a critical role. Using the available experimental evidence, it is proposed that enormous synthesis of conventional FoxP3-Th cells (responsive) often renders subjects inherently vulnerable to IRIS, whereas that of natural FoxP3+Treg cell synthesis predominate among subjects that may not progress to IRIS. We also propose that IRIS non-developers generate precursor T-cells with a high avidity to generate CD4+CD25+FoxP3+ Tregs whereas IRIS developers generate T-cells of intermediate avidity yielding Th0 cells and effector T-cells to mediate the generation of proinflammatory cytokines in response to cell-signaling factors (IL-2, IL-6 etc.). Researchers have shown that IL-10 Tregs (along with TGF-β, a known anti-inflammatory cytokine) limit immune responses against microbial antigens in addition to effectively controlling HIV replication, the prime objective of HAART. Although certain technical limitations are described herein, we advocate measures to test the role of Tregs in IRIS.
Under the volcano: phylogeography and evolution of the cave-dwelling Palmorchestia hypogaea(Amphipoda, Crustacea) at La Palma (Canary Islands)
Authors: Villacorta Carlos , Jaume Damià , Oromí Pedro , Juan Carlos
Published: February 2008

Background

The amphipod crustacean Palmorchestia hypogaea occurs only in La Palma (Canary Islands) and is one of the few terrestrial amphipods in the world that have adapted to a strictly troglobitic life in volcanic cave habitats. A surface-dwelling closely related species (Palmorchestia epigaea) lives in the humid laurel forest on the same island. Previous studies have suggested that an ancestral littoral Orchestia species colonized the humid forests of La Palma and that subsequent drought episodes in the Canaries reduced the distribution of P. epigaea favouring the colonization of lava tubes through an adaptive shift. This was followed by dispersal via the hypogean crevicular system.

Results

P. hypogaea and P. epigaea did not form reciprocally monophyletic mitochondrial DNA clades. They showed geographically highly structured and genetically divergent populations with current gene flow limited to geographically close surface locations. Coalescence times using Bayesian estimations assuming a non-correlated relaxed clock with a normal prior distribution of the age of La Palma, together with the lack of association of habitat type with ancestral and recent haplotypes, suggest that their adaptation to cave life is relatively ancient.

Conclusion

The data gathered here provide evidence for multiple invasions of the volcanic cave systems that have acted as refuges. A re-evaluation of the taxonomic status of the extant species of Palmorchestia is needed, as the division of the two species by habitat and ecology is unnatural. The information obtained here, and that from previous studies on hypogean fauna, shows the importance of factors such as the uncoupling of morphological and genetic evolution, the role of climatic change and regressive evolution as key processes in leading to subterranean biodiversity.
Expression of AMPA Receptor Subunits at Synapses in Laminae I–III of the Rodent Spinal Dorsal Horn
Authors: Polgár Erika , Watanabe Masahiko , Hartmann Bettina , Grant Seth GN , Todd Andrew J
Published: February 2008

Background:

Glutamate receptors of the AMPA type (AMPArs) mediate fast excitatory transmission in the dorsal horn and are thought to underlie perception of both acute and chronic pain. They are tetrameric structures made up from 4 subunits (GluR1–4), and subunit composition determines properties of the receptor. Antigen retrieval with pepsin can be used to reveal the receptors with immunocytochemistry, and in this study we have investigated the subunit composition at synapses within laminae I–III of the dorsal horn. In addition, we have compared staining of AMPArs with that for PSD-95, a major constituent of glutamatergic synapses. We also examined tissue from knock-out mice to confirm the validity of the immunostaining.

Results:

As we have shown previously, virtually all AMPAr-immunoreactive puncta were immunostained for GluR2. In laminae I–II, ~65% were GluR1-positive and ~60% were GluR3-positive, while in lamina III the corresponding values were 34% (GluR1) and 80% (GluR3). Puncta stained with antibody against the C-terminus of GluR4 (which only detects the long form of this subunit) made up 23% of the AMPAr-containing puncta in lamina I, ~8% of those in lamina II and 46% of those in lamina III. Some overlap between GluR1 and GluR3 was seen in each region, but in lamina I GluR1 and GluR4 were present in largely non-overlapping populations. The GluR4 puncta often appeared to outline dendrites of individual neurons in the superficial laminae. Virtually all of the AMPAr-positive puncta were immunostained for PSD-95, and 98% of PSD-95 puncta contained AMPAr-immunoreactivity. Staining for GluR1, GluR2 and GluR3 was absent in sections from mice in which these subunits had been knocked out, while the punctate staining for PSD-95 was absent in mice with a mutation that prevents accumulation of PSD-95 at synapses.

Conclusion:

Our results suggest that virtually all glutamatergic synapses in laminae I–III of adult rat spinal cord contain AMPArs. They show that synapses in laminae I–II contain GluR2 together with GluR1 and/or GluR3, while the long form of GluR4 is restricted to specific neuronal populations, which may include some lamina I projection cells. They also provide further evidence that immunostaining for AMPAr subunits following antigen retrieval is a reliable method for detecting these receptors at glutamatergic synapses.
Isolation of a strong Arabidopsis guard cell promoter and its potential as a research tool
Authors: Yang Yingzhen , Costa Alex , Leonhardt Nathalie , Siegel Robert S , Schroeder Julian I
Published: February 2008

Background

A common limitation in guard cell signaling research is that it is difficult to obtain consistent high expression of transgenes of interest in Arabidopsis guard cells using known guard cell promoters or the constitutive 35S cauliflower mosaic virus promoter. An additional drawback of the 35S promoter is that ectopically expressing a gene throughout the organism could cause pleiotropic effects. To improve available methods for targeted gene expression in guard cells, we isolated strong guard cell promoter candidates based on new guard cell-specific microarray analyses of 23,000 genes that are made available together with this report.

Results

A promoter, pGC1(At1g22690), drove strong and relatively specific reporter gene expression in guard cells including GUS (beta-glucuronidase) and yellow cameleon YC3.60 (GFP-based calcium FRET reporter). Reporter gene expression was weaker in immature guard cells. The expression of YC3.60 was sufficiently strong to image intracellular Ca2+ dynamics in guard cells of intact plants and resolved spontaneous calcium transients in guard cells. The GC1 promoter also mediated strong reporter expression in clustered stomata in the stomatal development mutant too-many-mouths (tmm). Furthermore, the same promoter::reporter constructs also drove guard cell specific reporter expression in tobacco, illustrating the potential of this promoter as a method for high level expression in guard cells. A serial deletion of the promoter defined a guard cell expression promoter region. In addition, anti-sense repression using pGC1 was powerful for reducing specific GFP gene expression in guard cells while expression in leaf epidermal cells was not repressed, demonstrating strong cell-type preferential gene repression.

Conclusion

The pGC1 promoter described here drives strong reporter expression in guard cells of Arabidopsis and tobacco plants. It provides a potent research tool for targeted guard cell expression or gene silencing. It is also applicable to reduce specific gene expression in guard cells, providing a method for circumvention of limitations arising from genetic redundancy and lethality. These advances could be very useful for manipulating signaling pathways in guard cells and modifying plant performance under stress conditions. In addition, new guard cell and mesophyll cell-specific 23,000 gene microarray data are made publicly available here.
Dissecting the logical types of network control in gene expression profiles
Authors: Marr Carsten , Geertz Marcel , Hütt Marc-Thorsten , Muskhelishvili Georgi
Published: February 2008

Background

In the bacterium Escherichia coli the transcriptional regulation of gene expression involves both dedicated regulators binding specific DNA sites with high affinity and also global regulators – abundant DNA architectural proteins of the bacterial nucleoid binding multiple sites with a wide range of affinities and thus modulating the superhelical density of DNA. The first form of transcriptional regulation is predominantly pairwise and specific, representing digitial control, while the second form is (in strength and distribution) continuous, representing analog control.

Results

Here we look at the properties of effective networks derived from significant gene expression changes under variation of the two forms of control and find that upon limitations of one type of control (caused e.g. by mutation of a global DNA architectural factor) the other type can compensate for compromised regulation. Mutations of global regulators significantly enhance the digital control, whereas in the presence of global DNA architectural proteins regulation is mostly of the analog type, coupling spatially neighboring genomic loci. Taken together our data suggest that two logically distinct – digital and analog – types of control are balancing each other.

Conclusion

By revealing two distinct logical types of control, our approach provides basic insights into both the organizational principles of transcriptional regulation and the mechanisms buffering genetic flexibility. We anticipate that the general concept of distinguishing logical types of control will apply to many complex biological networks.