bluuebunny/crossref_metadata_2025 huggingface dataset:
Xanthatin and xanthinosin from the burs ofXanthium strumariumL. as potential anticancer agentsThis article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Ramírez-Erosa Irving , Huang Yaoge , Hickie Robert A. , Sutherland Ronald G. , Barl Branka
Published: December 2007

Xanthatin and xanthinosin, 2 sesquiterpene lactones isolated from the burs of Xanthiun strumarium L. (cocklebur), showed moderate to high in vitro cytotoxic activity in the human cancer cell lines WiDr ATCC (colon), MDA-MB-231 ATCC (breast), and NCI-417 (lung). Xanthatin and xanthinosin were purified as the result of a multi-screening bioassay-guided study of wild plant species of the family Asteraceae, collected from various sites in Saskatchewan, Canada. Seventy-five extracts at a single concentration of 100 μg/mL were evaluated for in vitro cytotoxicity to the human cancer cell lines used. The chloroform extract of Carduus nutans L. (nodding thistle) aerial parts (IC50, 9.3 μg/mL) and the hexane extract of Echinacea angustifolia DC. (narrow-leaved purple coneflower) root (IC50, 4.0 μg/mL) were moderately to highly cytotoxic to the lung cancer cell line. The chloroform extracts of X. strumarium L. burs and Tanacetum vulgare L. (tansy) aerial parts exhibited the highest cytotoxicity for all cell lines tested; their IC50values, obtained from multidose testing, ranged from 0.1 to 6.2 μg/mL (X. strumarium) and from 2.4 to 9.1 μg/mL (T. vulgare). Further purification of the chloroform fraction of X. strumarium yielded xanthatin and xanthinosin in high yields. This is the first time that these compounds have been reported in the burs of X. strumarium. Their IC50values are also reported herein.
Spontaneous temperature changes in the 2-vessel occlusion model of cerebral ischemia in rats
Authors: Clark Darren L. , DeButte-Smith Maxine , Colbourne Frederick
Published: December 2007

Transient global ischemia (ISC) in rats and humans causes selective and delayed neuronal death in the hippocampal CA1 sector. It is clear from rodent studies that hyperthermia aggravates, whereas hypothermia lessens, this injury. In this study we sought to relate core (Tc) and brain (Tb) temperature, measured via telemetry probes, after ISC produced in rats by bilateral common carotid artery occlusion combined with systemic hypotension (2-VO model). We also tested whether spontaneous postischemic temperature fluctuations occurred and whether they were related to cell death as previous studies indicate. We report that Tc and Tb readings are similar and are highly correlated before and after 10 min of 2-VO ISC. In the second experiment, rats were subjected to 8, 9, or 10 min of 2-VO ISC. Despite a range in CA1 injury among these animals, there was no evidence of post-ISC hyperthermia, contrary to earlier work, and neither temperature nor the physiological variables measured during ISC (e.g., glucose) predicted injury. Our findings suggest that, under the present conditions, 2-VO rats do not experience postoperative hyperthermia, which can be adequately measured with Tc telemetry probes.
The effects of agricultural practices on arbuscular mycorrhizal fungi
Authors: Jansa Jan , Wiemken Andres , Frossard Emmanuel
Published: December 2007

Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with the majority of land plants, including many important agricultural crops. These fungi facilitate plant nutrient uptake, promote soil aggregation and use a significant portion of reduced carbon from the plants. AMF functional traits differ considerably among and within species, meaning that functional properties of a mycorrhizal community depend on its composition. Here we review studies exploring the effects of agricultural practices such as tillage, crop rotation, fertilization, pesticide application, irrigation and grazing on AMF communities. Although it is difficult to generalize the results of studies performed under different soil and climatic conditions, some universal patterns emerge. For example, soil tillage reduces the abundance of
Scutellospora
spp.; phosphorus fertilization lowers the extent of AMF root colonization; and diversification of crops results in more diverse AMF communities. We now need to design simple and reliable field tests for quantifying the effects of AMF communities on crop growth, yields and sustainability of the agro-ecosystems.
Perspectives on the relationship between soil science and geology
Authors: Ugolini F. C. , Warkentin B. P.
Published: December 2007

Soil science came into its own only in the 20th century. Before this, the study of soils was dominated by geologists, agronomists and chemists. It was Dokuchaev in 1886, who recognized soil as a physical entity with properties acquired from the impact of soil-forming factors, among which the geological substrate was only one. This vision resulted in the establishment of a new discipline, called pedology. With time, geologists began to appreciate soil in a pedological context. In fact, palaeosols in particular have been utilized to interpret the stratigraphy of metamorphic and sedimentary rocks and Quaternary deposits. Also, palaeosols have been used for correlating unconsolidated sediments, faults and neotectonics, or for the relative dating of deposits or surfaces. Weathering is a field where soil chemists have interacted with geochemists to evaluate chemical denudation and landscape evolution. Geological engineering in terms of water storage, pollutant transport, and critical load, in addition to location, design and construction of roads, is another area of interaction between soil researchers and geologists. The exploration of the planets of the solar system is a field which has assembled soil chemists and geochemists to collect, analyse and interpret data sent by space vehicles. Future interactions between geology and soil science will occur on issues such as: water in the vadose zone; risks due to Earth movements; and functions of soils in ecosystems. We predict and also welcome more communication between the two disciplines, as solutions to some of these problems are demanded by society.
The use of two- and three-dimensional seismic to understand sediment transfer from fluvial to deepwater via sinuous channels: example from the Mahakam shelf and comparison with outcrop data (south central Pyrenees)
Authors: Crumeyrolle P. , Renaud I. , Suiter J.
Published: December 2007

While being very different in term of horizontal and vertical resolution, the three-dimensional seismic and the two-dimensional lines straddling the Mahakam shelf complement each other to refine the classical two-dimensional seismic-based sequence stratigraphy models and the associated depositional environments interpretation by establishing closer three-dimensional genetic relations between fluvial, deltaic and turbiditic sediments using palaeolandscape morphologies. The Mahakam lowstand seismic geomorphology study can be compared with ancient sinuous fluvial to slope and deep marine channels outcropping in the cenozoic of the Spanish Pyrenees. This comparison emphasizes the interaction of various processes such as sea-level cycles, shelf-edge failures and the behaviour of flood/fluvial flows shaping the fluvial conduits that fed turbiditic systems during the lowstand period. Fluvial-derived flows by-passing the depositional shoreline break or the shelf break appear to be one of the main mechanisms for sediment transfer from shelf to deep basin both in the Mahakam and the Sobrarbe delta despite the obvious difference in tectonic setting, slope dip and flow efficiency.
Imprints of former ice streams, imaged and interpreted using industry three-dimensional seismic data from the south-western Barents Sea
Authors: Andreassen K. , Ødegaard C. M. , Rafaelsen B.
Published: December 2007

Former ice-stream activity is shown from industry three-dimensional (3D) seismic data from the south-western Barents Sea. Although designed for deeper targets, the data allow, due to high spatial sample rate and three-dimensional migration techniques, construction of detailed plan view images. The integration of sea-floor geomorphology with stratigraphy documents the importance of glacial processes in the seascape evolution of this area. Fast-flowing ice streams occupying the cross-shelf troughs during the Late Weichselian glaciation caused large-scale erosion, and also left their imprints in the form of mega-scale glacial lineations on the sea floor as indicators of ice-flow direction. Various types of 3D seismic attributes, combined with detailed geomorphology and seismic stratigraphy, are used to investigate the 2–3 km of stratigraphic record that corresponds to over a million years of ice-stream activity. The appearance of mega-scale glacial lineations on various 3D seismic attribute maps indicates, together with other characteristics of ice streams, that they are formed by erosion beneath fast-flowing grounded ice. Bedform records of former ice streams may, however, be related only to the final stages of ice-streaming, immediately prior to shut down. Because we here have preserved up to several hundred metres of sediments between the buried, glacially eroded surfaces, we have the opportunity to study ice-stream imprints and associated processes covering longer time spans than just the last stages. Seismic volumetric attribute maps reveal that megablocks and rafts, often aligned in chains, commonly occur within the till units, implying that glaciotectonic erosion by fast-flowing ice streams was an important process in the transfer of sediments from the continental shelf to the Bjørnøya Trough Mouth Fan and the deep sea during the Plio-Pleistocene glaciations.
Application of three-dimensional seismic data to documenting the scale, geometry and distribution of soft-sediment features in sedimentary basins: an example from the Lomre Terrace, offshore Norway
Authors: Jackson C. A.-L.
Published: December 2007

Three-dimensional seismic data are used to document the geometry, scale and distribution of soft-sediment deformation features in the post-rift succession of the Lomre Terrace, offshore Norway. In the Cretaceous to Upper Oligocene succession a polygonal fault network, developed in the in response to compaction and dewatering of the interval, was mapped using dip and azimuth grid-based attributes. In the same stratigraphic interval a series of chaotic seismic reflection packages are developed which are visualized using a volume-based seismic coherency attribute and interpreted as the seismic expression of mobilized mud masses. Immediately overlying the mobilized mud masses are a series of fault-bounded depressions that are interpreted to have formed in response to deflation of the mobilized mud masses caused by loading of the overlying succession. A series of shallow, curvilinear erosion surfaces are present on the seismic horizon bounding the top of the Pliocene succession and represent iceberg-keel plough marks. This study demonstrates that interpretation and visualization of three-dimensional seismic data coupled with attribute analysis provide valuable insights into soft-sediment deformation features in sedimentary basins, in particular the scale, geometry and distribution of such features and their temporal and spatial inter-relationships.
Efficient field-sensitive pointer analysis of C
Authors: Pearce David J. , Kelly Paul H.J. , Hankin Chris
Published: December 2007

The subject of this article is flow- and context-insensitive pointer analysis. We present a novel approach for precisely modelling struct variables and indirect function calls. Our method emphasises efficiency and simplicity and is based on a simple language of set constraints. We obtain an
O
(
v
4
) bound on the time needed to solve a set of constraints from this language, where
v
is the number of constraint variables. This gives, for the first time, some insight into the hardness of performing field-sensitive pointer analysis of C. Furthermore, we experimentally evaluate the time versus precision trade-off for our method by comparing against the field-insensitive equivalent. Our benchmark suite consists of 11 common C programs ranging in size from 15,000 to 200,000 lines of code. Our results indicate the field-sensitive analysis is more expensive to compute, but yields significantly better precision. In addition, our technique has been integrated into the latest release (version 4.1) of the GNU Compiler GCC. Finally, we identify several previously unknown issues with an alternative and less precise approach to modelling struct variables, known as field-based analysis.
Assessing data mining results via swap randomization
Authors: Gionis Aristides , Mannila Heikki , Mielikäinen Taneli , Tsaparas Panayiotis
Published: December 2007

The problem of assessing the significance of data mining results on high-dimensional 0--1 datasets has been studied extensively in the literature. For problems such as mining frequent sets and finding correlations, significance testing can be done by standard statistical tests such as chi-square, or other methods. However, the results of such tests depend only on the specific attributes and not on the dataset as a whole. Moreover, the tests are difficult to apply to sets of patterns or other complex results of data mining algorithms. In this article, we consider a simple randomization technique that deals with this shortcoming. The approach consists of producing random datasets that have the same row and column margins as the given dataset, computing the results of interest on the randomized instances and comparing them to the results on the actual data. This randomization technique can be used to assess the results of many different types of data mining algorithms, such as frequent sets, clustering, and spectral analysis. To generate random datasets with given margins, we use variations of a Markov chain approach which is based on a simple swap operation. We give theoretical results on the efficiency of different randomization methods, and apply the swap randomization method to several well-known datasets. Our results indicate that for some datasets the structure discovered by the data mining algorithms is expected, given the row and column margins of the datasets, while for other datasets the discovered structure conveys information that is not captured by the margin counts.
On counting homomorphisms to directed acyclic graphs
Authors: Dyer Martin , Goldberg Leslie Ann , Paterson Mike
Published: December 2007

It is known that if P and NP are different then there is an infinite hierarchy of different complexity classes that lie strictly between them. Thus, if P ≠ NP, it is not possible to classify NP using any finite collection of complexity classes. This situation has led to attempts to identify smaller classes of problems within NP where
dichotomy
results may hold: every problem is either in P or is NP-complete. A similar situation exists for
counting
problems. If P ≠#P, there is an infinite hierarchy in between and it is important to identify subclasses of #P where dichotomy results hold. Graph homomorphism problems are a fertile setting in which to explore dichotomy theorems. Indeed, Feder and Vardi have shown that a dichotomy theorem for the problem of deciding whether there is a homomorphism to a fixed directed acyclic graph would resolve their long-standing dichotomy conjecture for all constraint satisfaction problems. In this article, we give a dichotomy theorem for the problem of counting homomorphisms to directed acyclic graphs. Let
H
be a fixed directed acyclic graph. The problem is, given an input digraph
G
, determine how many homomorphisms there are from
G
to
H
. We give a graph-theoretic classification, showing that for some digraphs
H
, the problem is in P and for the rest of the digraphs
H
the problem is #P-complete. An interesting feature of the dichotomy, which is absent from previously known dichotomy results, is that there is a rich supply of tractable graphs
H
with complex structure.
Equivalence between priority queues and sorting
Authors: Thorup Mikkel
Published: December 2007

We present a general deterministic linear space reduction from priority queues to sorting implying that if we can sort up to
n
keys in
S
(
n
) time per key, then there is a priority queue supporting delete and insert in
O
(
S
(
n
)) time and find-min in constant time. Conversely, a priority queue can trivially be used for sorting: first insert all keys to be sorted, then extract them in sorted order by repeatedly deleting the minimum. Asymptotically, this settles the complexity of priority queues in terms of that of sorting.

Previously, at SODA'96, such a result was presented by the author for the special case of monotone priority queues where the minimum is not allowed to decrease.

Besides nailing down the complexity of priority queues to that of sorting, and vice versa, our result yields several improved bounds for linear space integer priority queues with find-min in constant time:

Deterministically
. We get
O
(log log
n
) update time using a sorting algorithm of Han from STOC'02. This improves the
O
((log log
n
)(log log log
n
)) update time of Han from SODA'01.

Randomized
. We get
O
(√log log
n
) expected update time using a randomized sorting algorithm of Han and Thorup from FOCS'02. This improves the
O
(log log
n
) expected update time of Thorup from SODA'96.

Deterministically in AC
0
(without multiplication)

. For any ε > 0, we get
O
((log log
n
)
1+ε
) update time using an AC
0
sorting algorithm of Han and Thorup from FOCS'02. This improves the
O
((log log
n
)
2
) update time of Thorup from SODA'98.

Randomized in AC
0

. We get
O
(log log
n
) expected update time using a randomized AC
0
sorting algorithm of Thorup from SODA'97. This improves the
O
((log log
n
)
1+ε
) expected update time of Thorup also from SODA'97.

The above bounds assume that each integer is stored in a single word and that word operations take unit time as in the word RAM.
A testing scenario for probabilistic processes
Authors: Cheung Ling , Stoelinga Mariëlle , Vaandrager Frits
Published: December 2007

We introduce a notion of finite testing, based on statistical hypothesis tests, via a variant of the well-known trace machine. Under this scenario, two processes are deemed observationally equivalent if they cannot be distinguished by any finite test. We consider processes modeled as image finite probabilistic automata and prove that our notion of observational equivalence coincides with the trace distribution equivalence proposed by Segala. Along the way, we give an explicit characterization of the set of probabilistic generalize the
Approximation Induction Principle
by defining an also prove limit and convex closure properties of trace distributions in an appropriate metric space.
The book review column
Authors: Gasarch William
Published: December 2007

In this column we review the following books.

1.
The Political Mapping of Cyberspace
by Jeremy W. Crampton. Reviewed by Rajesh Natarajan.

2.
Probability and Computing: Randomized Algorithms and Probabilitic Analysis
by Michael Mitzenmacher and Eli Upfal. There are two reviews, one by Jonathan Katz and one by Yannis C. Stamatiou.

3.
Computational Techniques of the Simplex Method
by István Maros. Review by Brian Borchers.
Introduction
Authors: Rajsbaum Sergio
Published: December 2007

The Distributed Computing Column covers the theory of systems that are composed of a number of interacting computing elements. These include problems of communication and networking, databases, distributed shared memory, multiprocessor architectures, operating systems, verification, Internet, and the Web. This issue consists of:

"Delayed Password Disclosure," by Markus Jakobsson and Steven Myers.

Many thanks to them for their contribution to this issue.
Introduction
Authors: Pucella Riccardo
Published: December 2007

In this issue, Lomuscio and Penczek survey some of the recent work in verification of temporal-epistemic logic via symbolic model checking, focussing on OBDD-based and SAT-based approaches for epistemic logics built on discrete and real-time branching time temporal logics.
Introduction
Authors: Khuller Samir
Published: December 2007

This issue's column is written by guest columnist, Chandra Chekuri. I am delighted that he agreed to write this column on a topic related to robust network design that has received considerable attention recently. His column introduces the reader to several recent results and provides references for further readings.
Serotonin Modulation of Moth Central Olfactory Neurons
Authors: Kloppenburg Peter , Mercer Alison R.
Published: December 2007

In the tobacco hornworm, Manduca sexta, 5-hydroxytryptamine (5HT) acting at the level of the antennal lobes contributes significantly to changing the moth's responsiveness to olfactory stimuli. 5HT targets K+conductances in the cells, increasing the excitability of central olfactory neurons and their responsiveness to olfactory cues. Effects of 5HT modulation are apparent not only at the single cell level, but also in the activity patterns of populations of neurons that convey olfactory information from antennal lobes to higher centers of the brain. Evidence suggests that 5HT-induced changes in activity within neural circuits of the antennal lobes might also drive structural plasticity, providing the basis for longer-term changes in antennal lobe function.
Liver sinusoidal endothelial cells are the principal site for elimination of unfractionated heparin from the circulation
Authors: Øie Cristina Ionica , Olsen Randi , Smedsrød Bård , Hansen John-Bjarne
Published: December 2007

The mechanism of elimination of blood borne heparin was studied. To this end unfractionated heparin (UFH) was tagged with FITC, which served as both a visual marker and a site of labeling with125I-iodine. UFH labeled in this manner did not alter the anticoagulant activity or binding specificity of the glycosaminoglycan. Labeled heparin administered intravenously to rats (0.1 IU/kg) had a circulatory t1/2of 1.7 min, which was increased to 16 min upon coinjection with unlabeled UFH (100 IU/kg). At 15 min after injection, 71% of recovered radioactivity was found in liver. Liver cell separation revealed the following relative uptake capacity, expressed per cell: liver sinusoidal endothelial cell (LSEC)-parenchymal cell-Kupffer cell = 15:3.6:1. Fluorescence microscopy on liver sections showed accumulation of FITC-UFH only in cells lining the liver sinusoids. No fluorescence was detected in parenchymal cells or endothelial cells lining the central vein. Fluorescence microscopy of cultured LSECs following binding of FITC-UFH at 4°C and chasing at 37°C, showed accumulation of the probe in vesicles located at the periphery of the cells after 10 min, with transfer to large, evenly stained vesicles in the perinuclear region after 2 h. Immunogold electron microscopy of LSECs to probe the presence of FITC following injection of FITC-UFH along with BSA-gold to mark lysosomes demonstrated colocalization of the probe with the gold particles in the lysosomal compartment. Receptor-ligand competition experiments in primary cultures of LSECs indicated the presence of a specific heparin receptor, functionally distinct from the hyaluronan/scavenger receptor (Stabilin2). The results suggest a major role for LSECs in heparin elimination.
Early changes of lung function and structure in an elastase model of emphysema—a hyperpolarized3He MRI study
Authors: Emami Kiarash , Cadman Robert V. , Woodburn John M. , Fischer Martin C. , Kadlecek Stephen J. , Zhu Jianliang , Pickup Stephen , Guyer Richard A. , Law Michelle , Vahdat Vahid , Friscia Michael E. , Ishii Masaru , Yu Jiangsheng , Gefter Warren B. , Shrager Joseph B. , Rizi Rahim R.
Published: December 2007

Early changes of lung function and structure were studied in the presence of an elastase-induced model of emphysema in 35 Sprague-Dawley rats at mild (5 U/100 g) and moderate (10 U/100 g) severities. Lung ventilation was measured on a regional basis (at a planar resolution of 3.2 mm) by hyperpolarized3He MRI at 5 and 10 wk after model induction. Subsequent to imaging, average alveolar diameter was measured from histological slices taken from the centers of each lobe. Changes of mean fractional ventilation, mean linear intercept, and intrasubject heterogeneity of ventilation were studied during disease progression. Mean fractional ventilation was significantly different between healthy controls (0.23 ± 0.04) and emphysematous animals at both time points in the 10-unit group (0.06 ± 0.02 and 0.12 ± 0.05, respectively). Changes in average alveolar diameter were not statistically observable until the 10th wk between healthy (37 ± 10 μm) and emphysematous rats (73 ± 25 and 95 ± 31 μm, for 5 and 10 units, respectively). Assessment of function-structure correlation suggested that the majority of the decline in fractional ventilation occurred in the first 5 wk, while enlargement of alveolar diameters appeared primarily between the 5th and 10th wk. A thresholding metric, based on the 20th percentile of fractional ventilation over the entire lung, was utilized to detect the onset of the disease with confidence, independent of whether the regional ventilation measurements were normalized with respect to the delivered tidal volume and estimated functional residual capacity of each individual rat.
AMP-activated protein kinase phosphorylates transcription factors of the CREB family
Authors: Thomson D. M. , Herway S. T. , Fillmore N. , Kim H. , Brown J. D. , Barrow J. R. , Winder W. W.
Published: December 2007

AMP-activated protein kinase (AMPK) has been identified as a regulator of gene transcription, increasing mitochondrial proteins of oxidative metabolism as well as hexokinase expression in skeletal muscle. In mice, muscle-specific knockout of LKB1, a component of the upstream kinase of AMPK, prevents contraction- and 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR)-induced activation of AMPK in skeletal muscle, and the increase in hexokinase II protein that is normally observed with chronic AICAR activation of AMPK. Since previous reports show a cAMP response element in the promoter region of the hexokinase II gene, we hypothesized that the cAMP-response element (CRE) binding protein (CREB) family of transcription factors could be targets of AMPK. Using radioisotopic kinase assays, we found that recombinant and rat liver and muscle AMPK phosphorylated CREB1 at the same site as cAMP-dependent protein kinase (PKA). AMPK was also found to phosphorylate activating transcription factor 1 (ATF1), CRE modulator (CREM), and CREB-like 2 (CREBL2), but not ATF2. Treatment of HEK-293 cells stably transfected with a CREB-driven luciferase reporter with AICAR increased luciferase activity approximately threefold over a 24-h time course. This increase was blocked with compound C, an AMPK inhibitor. In addition, AICAR-induced activation of AMPK in incubated rat epitrochlearis muscles resulted in an increase in both phospho-acetyl-CoA carboxylase and phospho-CREB. We conclude that CREB and related proteins are direct downstream targets for AMPK and are therefore likely involved in mediating some effects of AMPK on expression of genes having a CRE in their promoters.
Molecular Basis for
Staphylococcus aureus
–Mediated Platelet Aggregate Formation Under Arterial Shear In Vitro
Authors: Kerrigan Steven W. , Clarke Niamh , Loughman Anthony , Meade Gerardene , Foster Timothy J. , Cox Dermot
Published: December 2007

Objective—

Staphylococcus aureus
is the most frequent causative organism of infective endocarditis (IE) and is characterized by thrombus formation on a cardiac valve that can embolize to a distant site. Previously, we showed that
S aureus
clumping factor A (ClfA) and fibronectin-binding protein A (FnBPA) can stimulate rapid platelet aggregation.

Methods and Results—

In this study we investigate their relative roles in mediating aggregate formation under physiological shear conditions. Platelets failed to interact with immobilized wild-type
S aureus
(Newman) at shear rates <500 s
−1
but rapidly formed an aggregate at shear rates >800 s
−1
. Inactivation of the ClfA gene eliminated aggregate formation at any shear rate. Using surrogate hosts that do not interact with platelets bacteria overexpressing ClfA supported rapid aggregate formation under high shear with a similar profile to Newman whereas bacteria overexpressing FnBPA did not. Fibrinogen binding to ClfA was found to be essential for aggregate formation although fibrinogen-coated surfaces only allowed single-platelets to adhere under all shear conditions. Blockade of the platelet immunoglobulin receptor FcγRIIa inhibited aggregate formation.

Conclusions—

Thus, fibrinogen and IgG binding to ClfA is essential for aggregate formation under arterial shear conditions and may explain why
S aureus
is the major cause of IE.
Biochemical Importance of Glycosylation in Thrombin Activatable Fibrinolysis Inhibitor
Authors: Buelens Karlien , Hillmayer Kerstin , Compernolle Griet , Declerck Paul J. , Gils Ann
Published: December 2007

Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa) exerts an antifibrinolytic effect by removing C-terminal lysines from partially degraded fibrin. These lysines are essential for a rapid conversion of plasminogen to plasmin by tissue type plasminogen activator. TAFI is heavily glycosylated at Asn
22
, Asn
51
, Asn
63
, and Asn
86
. Although the glycans occurring at the glycosylation sites have previously been identified, the biochemical role of these glycans is not known yet. Therefore, we have determined the biochemical importance of the glycosylation in TAFI. Four single, 6 double, 4 triple, and 1 quadruple mutant, in which asparagine was replaced by glutamine, were constructed and transfected into HEK293T cells. Based on the determination of antigen and activity levels on conditioned medium, 4 single and 1 triple mutant were purified and their biochemical properties were determined. The glycosylation knockout mutants did neither reveal an altered fragmentation pattern nor differences in TAFIa stability, but TAFI-N51Q, TAFI-N63Q, and TAFI-N22Q-N51Q-N63Q revealed a decreased TAFIa activity, an increased intrinsic catalytic activity of the zymogen, and a decreased antifibrinolytic potential compared with TAFI–wild-type, whereas TAFI-N22Q and TAFI-N86Q revealed an increased antifibrinolytic potential probably because of an increased catalytic efficiency toward the physiological substrate. From these data it can be concluded that mainly the glycosylation at Asn
86
contributes to the biochemical characteristics of TAFI. Furthermore we provide evidence that the activation peptide stays in close proximity to the TAFIa moiety after activation.
Oxidative Stress and Matrix Metalloproteinase-9 in Acute Ischemic Stroke
Authors: Kelly Peter J. , Morrow Jason D. , Ning MingMing , Koroshetz Walter , Lo Eng H. , Terry Erin , Milne Ginger L. , Hubbard Jane , Lee Hang , Stevenson Elizabeth , Lederer Megan , Furie Karen L
Published: December 2007

Background and Purpose—

Experimental stroke studies indicate that oxidative stress is a major contributing factor to ischemic cerebral injury. Oxidative stress is also implicated in activation of matrix metalloproteinases (MMPs) and blood-brain barrier injury after ischemia-reperfusion. Plasma biomarkers of oxidative stress may have utility as early indicators of efficacy in Phase 2 trials of antioxidant therapies in human stroke. To date, a valid biomarker has been unavailable. We measured F2-isoprostanes (F2IPs), free-radical induced products of neuronal arachadonic acid peroxidation, in acute ischemic stroke. We aimed to determine the change in plasma F2IP levels over time and relationship with plasma MMP-9 in tPA-treated and tPA-untreated stroke patients.

Methods—

We performed a case–control study of consecutive ischemic stroke patients (25 tPA-treated and 27 tPA-untreated) presenting within 8 hours of stroke onset. Controls were individuals without prior stroke from a primary care clinic network serving the source population from which cases were derived. Infarct volume was determined on acute diffusion-weighted MRI (DWI) performed within 48 hours using a semi-automated computerized segmentation algorithm. Phlebotomy was performed at <8 hours, 24 hours, 2 to 5 days, and 4 to 6 weeks. F2IPs were measured by gas chromatography/mass spectrometry and MMP-9 by ELISA. Prestroke antioxidant dietary intake was measured by the 24-hour recall method.

Results—

In 52 cases and 27 controls, early (median 6 hours postonset) F2IPs were elevated in stroke cases compared with controls (medians 0. 041 versus 0.0295pg/mL,
P
=0.012). No difference in F2IPSs was present at later time points. Early plasma F2IPs correlated with MMP-9 in all patients (
P
=0.01) and the tPA-treated subgroup (
P
=0.02). No correlation was found with NIHSS, DWI infarct volume, 90-day Rankin score, or C-reactive protein (
P
>0.05 for all).

Conclusions—

In early human stroke we found evidence of increased oxidative stress and a relationship with MMP-9 expression, supporting findings from experimental studies.
Impact of Preexisting Depression on Length of Stay and Discharge Destination Among Patients Hospitalized for Acute Stroke
Authors: Nuyen Jasper , Spreeuwenberg Peter M. , Groenewegen Peter P. , van den Bos Geertrudis A.M. , Schellevis François G.
Published: December 2007

Background and Purpose—

There exists limited knowledge regarding the relation between depression and healthcare utilization in stroke patients. The objective of this register-based study was to examine the impact of having preexisting depression at the time of hospital admission for acute stroke on length of hospital stay and discharge destination.

Methods—

Data from a general-practice database were linked to those of a hospital database to identify patients hospitalized for stroke and were used to categorize these patients into 3 groups based on preexisting mental health (MH) status at admission, ie, those with preexisting depression, those with another preexisting MH condition, and those without any preexisting MH condition. Multilevel analyses controlling for several potentially important covariates were performed to estimate the associations under study.

Results—

Both patients with preexisting depression (n=41) and those with another preexisting MH condition (n=62) did not differ significantly from patients without any preexisting MH condition (n=211) regarding length of hospital stay for acute stroke. Among patients who survived hospitalization, those with preexisting depression had significantly higher odds of being discharged to an institution instead of their home than did patients without any preexisting MH condition. Having another preexisting MH condition had no significant effect on discharge destination.

Conclusions—

Having preexisting depression at admission seems to be a relevant factor in determining discharge to institutional care after acute stroke hospitalization. Further research is needed to determine the mechanism(s) through which preexisting depression decreases the chances of being discharged to home.
Evidence of Abnormal Lower-Limb Torque Coupling After Stroke
Authors: Hayes Cruz Theresa , Dhaher Yasin Y.
Published: December 2007

Background and Purpose—

Although stroke survivors often display abnormal joint torque patterns, studies of torque-coupling in the lower limb are lacking, despite their potential impact on gait abnormalities.

Methods—

Twenty-two chronic ambulating stroke subjects and 11 age-matched control subjects produced isometric hip torques in the frontal and sagittal planes with the hemiparetic leg (or randomly selected leg for the control group) in postures that resemble stages of gait. The involuntary knee torques were also recorded although no feedback or instructions were given.

Results—

In the toe-off and midswing postures, the stroke group had a significant torque bias toward extension and adduction, whereas the control group had a symmetric torque space. The stroke group also produced significantly smaller torques than the control group in the flexion and abduction/flexion directions. Finally, the stroke group displayed abnormal coupling of knee extension with hip adduction, unique to the toe-off position.

Conclusions—

Whereas gait abnormalities after stroke have been attributed to a number of factors, including sagittal plane strength impairments at the hip, knee, and ankle, our findings indicate that neuromechanical changes after stroke may play a significant role in determining the nature of the movement abnormality. Specifically, abnormal hip adduction and knee extension torque coupling was observed, in addition to direction-specific hip torque weakness. Future studies are needed to delineate the differential contributions of each potential factor to gait abnormalities. Understanding the underlying neuromechanical changes after stroke may aid the development of rehabilitation strategies.
Brazil: From Liberation Theology to a Theology of Citizenship as Public Theology
Authors: von Sinner Rudolf
Published: December 2007

Liberation Theology has become known worldwide for its preferential option for the poor and its prophetic voice against economic and political oppression. Since the end of the military regime in Brazil (1985) and the fall of the Berlin wall (1989), theologians have been grappling with the continuously appalling poverty, exclusion and marginalization of very large sectors of society, within an ever more complex context and a diversity of theoretical positions. In civil society, politics and education, citizenship has become the central notion behind participatory democracy. By describing what have been the main assets of Liberation Theology and how the new situation is challenging them, this article explores theological proposals from Brazilian authors, who have taken up the concern for citizenship. Hence, it states the need for a theology of citizenship and maps the field for linking this to the growing international debate on public theology; a phrase not commonly used in Brazil thus far.
Babel or Pentecost? Faith, Difference and Freedom in the Twenty-First Century: The Challenge for Public Theology
Authors: Shannahan Chris
Published: December 2007

This article emerges from many years work in diverse inner city communities. It suggests that urban Britain will be understood properly, and public theology engaged fully with contemporary society, by seriously exploring the normative and contested nature of difference. The article critiques the view that diversity poses a threat to communal life and exposes current examples of essentialist identity politics. It argues that identities premised on raciology are unsustainable, and this poses a challenge to which people of faith should respond with urgency. Thus, the article asserts that critical patterns of multiculturalism provide the basis for inclusive patterns of faith and identity, and that existing public theologies still need to engage in sufficient depth with the fluidity of identity in twenty-first century Britain. At heart, the article offers the new hermeneutical principle of liberative difference as having the capacity to reinvigorate patterns of faith and resource an inclusive liberative struggle in urban societies.
Sin and Decent Society: A Few Untimely Thoughts
Authors: Vroom Hendrik
Published: December 2007

This article discusses the brokenness of the world and roots of human wrongdoing. It argues that the acknowledgement of sin is a precondition for a humane society of compassion and solidarity. The ambiguity of laws is discussed: laws are necessary, but at the same time they lead us to think that we can improve ourselves. This way of thinking entails that, like the world, we can perfect ourselves. This article explores the consequences of wrong perceptions of human beings, brokenness and sin for individuals and society and points to the contribution that Christian public theology can make.
Electrospun PA-66 Coating on Textile Surfaces
Authors: Heikkilä Pirjo , Sipilä Auli , Peltola Minna , Harlin Ali , Taipale Aimo
Published: December 2007

Electrospinning was used to produce lightweight coatings of polyamide-66 nanofibers on different fibrous substrates. Filtration efficiency of coated and uncoated samples and strain capacity of the nanofiber layer were tested. Filtration efficiency clearly increased even with the lowest amount of nanofibers (0.02 g/m2) when compared to uncoated samples, and with the highest nanofiber coating weight (0.5 g/m2) the filtration efficiency of submicron aerosol particles was over 90%. Elongation capacity of the polyamide nanofiber layer was found to be insufficient to be used with elastic materials. The polyamide nanofiber layer is, therefore, suitable to be used with relatively rigid substrate e.g. spunbond nonwoven and at least thicker nanofiber layers are advisable to be protected with cover layer, because the nanofiber layer also delaminates easily from the textile surface.
Modelization of the Influence of the Wearing Conditions of the Garments on the Ultraviolet Protection Factor
Authors: Algaba Inés , Riva Ascensión , Pepió Montserrat
Published: December 2007

The aim of the paper was the modelization of the influence on the Ultraviolet Protection Factor (UPF) of the more representative properties of the wearing conditions of the garments, the tension produced in contact with the body and the wetness. The study was carried out on undyed woven fabrics manufactured with three different cellulosic fibers (Cotton, Modal and Modal Sun) and with three different structures. The transmission of Ultraviolet Radiation (UVR) in the whole ultraviolet range, as well as in the UVA and UVB regions, was measured and the UPF was determined. A statistical model for each fiber type was formulated, which allowed the prediction of the UPF according to the UPF of the original fabric (unstretched and dry), the tension and the wetness.
Reaction Mechanism of Dimethyloldihydroxyethyleneurea/ Alpha-amino Acids Co-reactants on the Crosslinking of Cotton Cellulose in the Presence of Aluminum Sulfate Catalyst
Authors: Chen Jui-Chin , Chen Cheng-Chi
Published: December 2007

Cotton fabrics were crosslinked with dimethyloldihydroxyethyleneurea (DMDHEU) alone and DMDHEU/alpha-amino acids. The results showed that the values of nitrogen content, dry crease recovery angle and wet crease recovery angle of the crosslinked fabrics were ranked as DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine under the same concentration of crosslinking agent. The reaction rate constant was also in the rank of DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine. This rank agreed with the number of amine groups on the alpha-amino acids. From the data of free energies of activation, we found that the alpha-amino acids could affect the crosslinking reaction. The transition state complex for DMDHEU alone was significantly different from those for DMDHEU/ alpha-amino acids. From infrared spectra, the interaction between alpha-amino acids and aluminum ion was confirmed. The mechanisms of the interaction between alpha-amino acids and aluminum ion and the condensation reaction mechanisms between DMDHEU and alpha-amino acids are suggested in this study. The higher the number of carboxylic acid groups contained in the alpha-amino acids, the higher the crease recovery angle and reaction rate constant.
Development of Novel Scaffolds for Tissue Engineering by Flock Technology
Authors: Walther Anja , Bernhardt Anne , Pompe Wolfgang , Gelinsky Michael , Mrozik Birgit , Hoffmann Gerald , Cherif Chokri , Bertram Helge , Richter Wiltrud , Schmack Gerhilt
Published: December 2007

Flock technology is a method well known in the textile industry. Short fibers are applied almost vertically on a substrate, coated with a flocking adhesive. Until now, this technology has not been used in the field of biomaterials. Our aim was to use electrostatic flocking for fabricating a novel type of scaffolds for tissue engineering. This method offers the possibility to create matrices with anisotropic properties that have a high compressive strength despite high porosity. First, experiments were performed using a membrane made of mineralized collagen as substrate, gelatine as adhesive and polyamide flock fibers. Different kinds of cells were cultured in the scaffolds for up to six weeks. Using microscopic methods and biochemical analyses, we could demonstrate that cells adhered and proliferated well in this new type of scaffold. Therefore, we can summarize that flocking is a technology suitable for fabrication of scaffolds for cell cultivation and tissue engineering.
Modification of Polylactic Acid Fiber with Enzymatic Treatment
Authors: Sawada K. , Urakawa H. , Ueda M.
Published: December 2007

Enzymatic modification of polylactic acid fibers is investigated using various kinds of protease and lipase. The effects of enzymes on the hydrolysis of polylactic acid fibers is evaluated by means of fiber weight loss, fiber strength and fiber surface observation. It is found that proteases derived from Bacillus subtilis and Bacillus licheniformis had remarkable activities on polylactic acid fibers. It is also observed that the hydrolysis of polylactic acid fibers with these enzymes causes a serious drop in fiber strength, although fiber weight loss is lower.
Avoiding Interference: Adult Attachment and Emotional Processing Biases
Authors: Edelstein Robin S. , Gillath Omri
Published: December 2007

The present study investigated attachment-related differences in emotional processing biases. Consistent with the proposal that avoidant individuals limit attention to potentially distressing information, attachment avoidance was associated with reductions in emotional Stroop (ES) interference for attachment-related words (e.g., intimate, loss). These biases were strongest among individuals who were currently in a romantic relationship, suggesting that being in a close relationship may activate avoidant defensive strategies. In addition, avoidant attentional biases were attenuated under cognitive load, suggesting that inhibiting attention to attachment-related information requires cognitive effort. Finally, avoidance was unrelated to ES performance for emotional, nonattachment-related words, demonstrating the specificity of these attentional biases. The present findings suggest that avoidant individuals can inhibit attention to potentially threatening information, that this ability requires cognitive effort, and that relationship status may be an important moderator of avoidant defensive strategies. The implications of these strategies for emotional functioning and well-being are discussed.
Forgiveness, Feeling Connected to Others, and Well-Being: Two Longitudinal Studies
Authors: Bono Giacomo , McCullough Michael E. , Root Lindsey M.
Published: December 2007

In two studies, the authors investigated the associations between interpersonal forgiveness and psychological well-being. Cross-sectional and prospective multilevel analyses demonstrated that increases in forgiveness (measured as fluctuations in individuals' avoidance, revenge, and benevolence motivations toward their transgressors) were related to within-persons increases in psychological well-being (measured as more satisfaction with life, more positive mood, less negative mood, and fewer physical symptoms). Moreover, forgiveness was more strongly linked to well-being for people who reported being closer and more committed to their partners before the transgression and for people who reported that their partners apologized and made amends for the transgression. Evidence for the reverse causal model, that increases in well-being were related to increases in forgiveness, was also found. However, changes in feelings of closeness toward the partner appeared to account for the associations of forgiveness with well-being, but not vice versa.