bluuebunny/crossref_metadata_2025 huggingface dataset:
An MRI-Based Method to Align the Compressive Loading Axis for Human Cadaveric Knees
Authors: Martin K. J. , Neu C. P. , Hull M. L.
Published: December 2007

There is a need to align the mechanical axis of the tibia with the axis of loading for studies involving tibiofemoral compression to interpret results and to ensure repeatability of loading within and among specimens. Therefore, the objectives of this study were (1) to develop a magnetic resonance imaging (MRI)-based alignment method for use with apparatuses applying tibiofemoral joint compression, (2) to demonstrate the usefulness of the method by aligning cadaveric knees in an apparatus that could apply tibiofemoral joint compression, and (3) to quantify the error associated with the alignment method. A four degree-of-freedom adjustable device was constructed to allow determination and alignment of the mechanical axis of the tibia of cadaveric knee joints with the axis of loading of an apparatus applying tibiofemoral joint compression. MRI was used to determine the locations of bony landmarks in three dimensions defining the mechanical axis of the tibia relative to an initial orientation of the four degree-of-freedom device. Adjustment values of the device were then computed and applied to the device to align the mechanical axis of the tibia with the axis of a compressive loading apparatus. To demonstrate the usefulness of the method, four cadaveric knees were aligned in the compressive loading apparatus. The vectors describing the mechanical axis of the tibia and the loading axis of the apparatus before and after adjustment of the four degree-of-freedom device were computed for each cadaveric knee. After adjustment of the four degree-of-freedom device, the mechanical axis of the tibia was collinear with the loading axis of the apparatus for each cadaveric knee. The errors in the adjustment values introduced by inaccuracies in the MR images were quantified using the Monte Carlo technique. The precisions in the translational and rotational adjustments were 1.20mm and 0.90deg respectively. The MR-based alignment method will allow consistent interpretation of results obtained during tibiofemoral compressive studies conducted using the apparatus described in this paper by providing a well-defined loading axis. The alignment method can also be adapted for use with other apparatuses applying tibiofemoral compression.
Assessment of Factors Influencing Finite Element Vertebral Model Predictions
Authors: Jones Alison C. , Wilcox Ruth K.
Published: December 2007

This study aimed to establish model construction and configuration procedures for future vertebral finite element analysis by studying convergence, sensitivity, and accuracy behaviors of semiautomatically generated models and comparing the results with manually generated models. During a previous study, six porcine vertebral bodies were imaged using a microcomputed tomography scanner and tested in axial compression to establish their stiffness and failure strength. Finite element models were built using a manual meshing method. In this study, the experimental agreement of those models was compared with that of semiautomatically generated models of the same six vertebrae. Both manually and semiautomatically generated models were assigned gray-scale-based, element-specific material properties. The convergence of the semiautomatically generated models was analyzed for the complete models along with material property and architecture control cases. A sensitivity study was also undertaken to test the reaction of the models to changes in material property values, architecture, and boundary conditions. In control cases, the element-specific material properties reduce the convergence of the models in comparison to homogeneous models. However, the full vertebral models showed strong convergence characteristics. The sensitivity study revealed a significant reaction to changes in architecture, boundary conditions, and load position, while the sensitivity to changes in material property values was proportional. The semiautomatically generated models produced stiffness and strength predictions of similar accuracy to the manually generated models with much shorter image segmentation and meshing times. Semiautomatic methods can provide a more rapid alternative to manual mesh generation techniques and produce vertebral models of similar accuracy. The representation of the boundary conditions, load position, and surrounding environment is crucial to the accurate prediction of the vertebral response. At present, an element size of 2×2×2mm3 appears sufficient since the error at this size is dominated by factors, such as the load position, which will not be improved by increasing the mesh resolution. Higher resolution meshes may be appropriate in the future as models are made more sophisticated and computational processing time is reduced.
A MR Imaging Procedure to Measure Tarsal Bone Rotations
Authors: Wolf P. , Luechinger R. , Boesiger P. , Stuessi E. , Stacoff A.
Published: December 2007

Magnetic resonance imaging offers unique insights into three-dimensional foot bone motion. Thereby, adequate devices enabling defined loading and positioning of the foot are needed to profit from this noninvasive procedure. Tarsal bone positions of three healthy subjects were repeatedly measured in a pronated and a supinated foot excursion under bodyweight with a newly developed MR imaging procedure. The quantification of the transferred motion from the loading and positioning device to the calcaneus and an estimation of the required degrees to distinguish between tarsal joint rotations were used to evaluate the applicability of the procedure to investigate tarsal joint motion. It was found that 45–70% (75–95%) of the externally applied 15deg foot pronation (supination) were transferred to the calcaneus. Furthermore, the talonavicular joint showed the largest amount of rotation up to 20deg eversion-inversion and abadduction, followed by the subtalar joint showing nearly half of that motion. Considerably less motion was found between the cuboid and calcaneus (about 2–6deg) and the cuboid nearly did not rotate relative to the navicular (on average 1deg). The estimated necessary differences between tarsal joint movements to identify individual kinematic behavior were in the order of 2deg (4deg related to the talonavicular joint). Since the results were in agreement with the literature, it is concluded that the applicability of the presented procedure to investigate tarsal bone mechanics is warranted. The possibility to evaluate 3D tarsal joint motion in combination with bone morphology (e.g., joint curvature) may provide new insights in the still uncertain relationship between foot function and foot morphology.
A Coupled Fluid-Structure Model of a Therapeutic Ultrasound Angioplasty Wire Waveguide
Authors: Gavin Graham P. , Dolan Finbar , Hashmi M. S. J. , McGuinness Garrett B.
Published: December 2007

Ultrasonic longitudinal displacements, delivered to the distal tips of small diameter wire waveguides, are known to be capable of disrupting complicated atherosclerotic plaques during vascular interventions. These ultrasonic displacements can disrupt plaques not only by direct contact ablation but also by pressure waves, associated cavitation, and acoustic streaming developed in the surrounding blood and tissue cavities. The pressure waves developed within the arterial lumen appear to play a major role but are complex to predict as they are determined by the distal tip output of the wire waveguide (both displacement and frequency), the geometric features of the waveguide tip, and the effects of biological fluid interactions. This work describes a numerical linear acoustic fluid-structure model of an ultrasonic wire waveguide and the blood surrounding the distal tip. The model predicts a standing wave structure in the wire waveguide, including stresses and displacements, and requires the incorporation of a damping constant. The effects on waveguide response of including an enlarged ball tip at the distal end of the waveguide, designed to enhance cavitation and surface contact area, are investigated, in addition to the effects of the surrounding blood on the resonant response of the waveguide. The model also predicts the pressures developed in the acoustic fluid field surrounding the ultrasonic vibrating waveguide tip and can predict the combinations of displacements, frequencies, and waveguide geometries associated with cavitation, an important event in the disruption of plaque. The model has been validated against experimental displacement measurements with a purpose built 23.5 kHz nickel-titanium wire waveguide apparatus and against experimental pressure measurements from the literature.
Genome of the Epsilonproteobacterial Chemolithoautotroph
Sulfurimonas denitrificans
Authors: Sievert Stefan M. , Scott Kathleen M. , Klotz Martin G. , Chain Patrick S. G. , Hauser Loren J. , Hemp James , Hügler Michael , Land Miriam , Lapidus Alla , Larimer Frank W. , Lucas Susan , Malfatti Stephanie A. , Meyer Folker , Paulsen Ian T. , Ren Qinghu , Simon Jörg ,   the USF Genomics Class
Published: December 2007

Sulfur-oxidizing epsilonproteobacteria are common in a variety of sulfidogenic environments. These autotrophic and mixotrophic sulfur-oxidizing bacteria are believed to contribute substantially to the oxidative portion of the global sulfur cycle. In order to better understand the ecology and roles of sulfur-oxidizing epsilonproteobacteria, in particular those of the widespread genus
Sulfurimonas
, in biogeochemical cycles, the genome of
Sulfurimonas denitrificans
DSM1251 was sequenced. This genome has many features, including a larger size (2.2 Mbp), that suggest a greater degree of metabolic versatility or responsiveness to the environment than seen for most of the other sequenced epsilonproteobacteria. A branched electron transport chain is apparent, with genes encoding complexes for the oxidation of hydrogen, reduced sulfur compounds, and formate and the reduction of nitrate and oxygen. Genes are present for a complete, autotrophic reductive citric acid cycle. Many genes are present that could facilitate growth in the spatially and temporally heterogeneous sediment habitat from where
Sulfurimonas denitrificans
was originally isolated. Many resistance-nodulation-development family transporter genes (10 total) are present; of these, several are predicted to encode heavy metal efflux transporters. An elaborate arsenal of sensory and regulatory protein-encoding genes is in place, as are genes necessary to prevent and respond to oxidative stress.
Selective tidal stream transport of adult sockeye salmon (Oncorhynchus nerka) in the Fraser River Estuary
Authors: Levy David A. , Cadenhead Allen D.
Published: December 2007

Mobile acoustic surveys of 24-h duration were undertaken at Steveston Bend between 1991 and 1993, close to the time of maximum adult Early Stuart sockeye salmon (Oncorhynchus nerka) abundance in the Fraser River estuary. During each survey, extreme variations in the abundance and directional orientation of fish targets appeared to be related to local flow direction and velocities. Acoustic Doppler Current Profiler (ADCP) measurements of water currents adjacent to the fish monitoring site showed that the water column stratified into two vertical layers under certain tidal conditions, with an upper outflowing layer over a lower inflowing layer. Under strong flood or ebb conditions, most of the water column was, respectively, inflowing or outflowing. Fish abundance in the water column appeared to be related primarily to tidal current variations. Maximum fish abundance and upstream orientation occurred during flood tidal periods with upstream current flows. We conclude that migrations of Early Stuart sockeye salmon are synchronized with the tidal cycle for energetically efficient net upstream displacement through the Fraser River estuary.
Trout population response to habitat enhancement in six northern Colorado streams
Authors: Riley Stephen C. , Fausch Kurt D.
Published: December 2007

We examined the effects of log drop structures on trout populations in six small, remote Rocky Mountain streams. Angling pressure was low on all streams, and most anglers killed no fish. Log drop structures were installed in 250-m treatment sections in summer 1988, and results were compared with adjacent 250-m control sections during 1987–1990. The structures caused marked changes in habitat, including greatly increased pool volume, decreased current velocity, and increased depth and cover. After the structures were installed, abundance and biomass of age-2 and older trout (and often age-1 trout) increased in all six streams, but there was no evidence that trout were in better condition or grew to larger sizes in most streams. Recaptures of tagged trout in two streams showed that the logs did not result in increased growth or survival of resident trout, although recaptures of fin-clipped trout in other streams suggested that apparent survival may have increased temporarily in treatment sections. Low recapture rates of marked trout and high percentages of unmarked adults indicated that immigration rates were high, suggesting that movement is an important mechanism to account for the increase in trout populations after habitat enhancement in these streams.
From picoplankton to microplankton: temperature-driven filtration by the unionid bivalve Lampsilis radiata siliquoidea in Lake St. Clair
Authors: Vanderploeg Henry A. , Liebig James R. , Nalepa Thomas F.
Published: December 2007

Size-selective filtration by the unionid bivalve Lampsilis radiata siliquoidea was determined seasonally for Lake St. Clair seston with special emphasis placed on determining retention efficiency of particles less than 1 μm equivalent spherical diameter (ESD). These results allowed us to estimate the aggregate clearance rates of Lampsilis and total unionids in the lake. Retention efficiency for seston in the 0.79–1.00 μm ESD size category was 0.44 whereas 0.07 was the corresponding value for 0.91-μm microspheres in laboratory prepared mixtures of microspheres and cultured algae; respective values for the 0.63–0.79 μm size category were not significantly different from zero. Particle shape may explain the difference between natural seston and microspheres. Particles in the picoplankton size range (<3 μm ESD) were probably an important food resource to the mussels, since 35–49% of the seston volume in Lake St. Clair was smaller than 3 μm ESD. Regression analyses of filtration rate as a function of temperature and food concentration showed that feeding rate was temperature driven and not saturated by available seston concentration. Lampsilis and total community clearance rates were maximum in September, with respective fractions of the water columns swept clear of 0.018 and 0.053∙d−1.
Factors associated with interannual and intraannual variation in nutrient limitation of phytoplankton growth in Castle Lake, California
Authors: Elser J. J. , Lubnow F. S. , Marzolf E. R. , Brett M. T. , Dion G. , Goldman C. R.
Published: December 2007

In a 3-year study of Castle Lake, California, potential nutrient (N,P) limitation of phytoplankton growth occurred rapidly (within 1–4 d of ice-out). Both N and P acted as potential limiting factors to phytoplankton growth in short-term (4–5 d) bioassays. Phytoplankton responded strongly to single additions of N or P in 1990 and 1992 but weakly so in 1991. This difference was associated with low inorganic N concentrations during spring 1991. In 1990 and 1991, variation of the primary limiting element correlated with the N:P ratio of the zooplankton community; phytoplankton tended to be N limited when the zooplankton was dominated by species with high N:P ratios (Diaptomus novamexicanus and Diacyclops thomasi: N:P ratios, by mass = 10.6–12.5) but limited by P when low N:P taxa (Daphnia rosea, N:P = 4.7) dominated. However, N vs. P limitation and zooplankton elemental data for 1992 did not fit the 1990–1991 pattern and there was no correlation for the 3-year data set. A field experiment demonstrated that the inorganic N:P ratio (NH4/SRP) increased dramatically with elevated Daphnia grazing but declined significantly with increased Diaptomus; this supported the 1990–1991 correlation between phytoplankton N/P limitation status and zooplankton community elemental ratio.
Bioenergetic analysis of prey consumption byBythotrephes cederstroemiin Lake Michigan
Authors: Yurista Peder M. , Schulz Kimberly L.
Published: December 2007

A bioenergetic model for Bythotrephes cederstroemi was constructed using measured physiological parameters to predict predation rates. The model predicts that juvenile B. cederstroemi will consume approximately 150% of their body weight per day, while adults consume 118% of their body weight per day. These rates are consistent with those of other invertebrate crustaceans. The predicted rate was twice that of an experimental measurement reported for Lake Huron B. cederstroemi; this discrepancy is attributed to experimental artifacts and to differences between B. cederstroemi populations in Lake Michigan and those in Lakes Huron and Erie. The model was most sensitive to estimation of ingestion and assimilation efficiencies and, secondarily, respiration coefficients. This model estimates the consumption rate of B. cederstroemi in Lake Michigan under optimal food resource conditions, and may be useful in predicting the future impact of B. cederstroemi predation on the zooplankton assemblages of other lakes.
Lipid composition off tissue and plasma in two mediterranean fishes, the gilt-head sea bream (Chrysophyrys auratus) and the European seabass (Dicentratchus labrx)
Authors: McClelland Grant , Weber Jean-Michel , Zwingelstein Georges , Brichon Gérard
Published: December 2007

The fatty acid (FA) composition of phospholipid (PL), triacylglycerol (TAG), and total lipid (TL) fractions was determined for liver, adipose tissue, white muscle, and plasma of European seabass (Dicentaratchus labrax) and gilt-head sea bream (Chrysophyrys auratus) fed on the same diet. FA composition of plasma nonesterified fatty acids (NEFA) and TAG as well as tissue TAG and TL correlates with that of the diet. FA composition of PL in tissues and plasma was different from that of the diet and different in the two species. Contribution to tissue wet weight of the different lipid fractions showed that both species store lipid primarily outside of muscle (only 3% in both species) as TAG in adipose tissue (about 80% lipid∙wet weight−1). Seabass store 33% wet weight of lipid in liver, while sea bream store only 5% wet weight. The plasma concentration of NEFA and TAG is 2223 and 12 260 nmol∙mL−1for seabass and 2790 and 9670 nmol∙mL−1for sea bream. The data show that these two fishes with similar lifestyle store lipid in the same fashion and that dietary FA composition affects the FA composition of TL and TAG fractions but not PL in tissue and plasma.
Impacts of climate change on the frequency and severity of floods in the Châteauguay River basin, Canada
Authors: Mareuil Arnaud , Leconte Robert , Brissette François , Minville Marie
Published: December 2007

This study aims at evaluating the hydrologic impacts of climate change on the Châteauguay River basin in the province of Quebec, Canada. Three global climate models (GCMs) covering a range of climate sensitivities were selected, and their output was employed to adjust the parameters of a stochastic weather generator using simple transformation rules for precipitation and temperature. Values of monthly precipitation and temperature were extracted from the GCMs for the current (1960–1990) and future (2040–2060) climate. The International Panel on Climate Change emission scenario known as B2 was selected. It represents an average scenario and corresponds approximately to a doubling of the atmospheric CO2 concentration. Resorting to stochastically generated climate scenarios allowed assessing whether the modelled effects of climate change on flows were statistically significant. Results indicate that spring and summer–fall peak flows were reduced on average by 30% and 12%, respectively, using the Echam4 model derived scenarios. The Hadcm3 model produced a weaker signal that was not statistically significant. The CGCM2 model produced a statistically significant reduction in spring peak flows of 8% on average, whereas the simulated reduction in summer flows was not statistically significant for many of the return periods considered. Many sources of uncertainties were partially considered in this study. One is the downscaling of the GCM climatology at the watershed scale. The approach employed to generate the future climate scenarios changed the precipitation variability through an adjustment of the parameters of the Gamma distribution function used to model precipitation amounts. Whether this approach is truly typical of climate change effect remains to be ascertained. Using more physically based hydrological models would help reduce uncertainties in climate change impacts studies.Key words: climate change, weather generator, flood, frequency analysis, hydrological modelling.
Numerical simulation of sediment transport and scouring by an offset jet
Authors: Boroomand Mohammad Reza , Salehi Neyshabouri S. Ali Akbar , Aghajanloo Kameleh
Published: December 2007

In this paper the offset jet entering a domain with a movable bed is simulated by the computer program FLUENT. To achieve this aim, sediment transport is numerically simulated using multiphase systems and the empirical coefficients are studied theoretically. The numerical results are verified by comparing the simulated total load with that obtained using existing formulae and concentration profiles from available measured data. In the final step, the offset jet scouring pattern is modeled qualitatively.Key words: offset jet, numerical simulation, FLUENT, multiphase system, turbulence, sediment, scouring.
Strain gradient effect on the behaviour and strength of masonry
Authors: Hou J , Liu Y
Published: December 2007

Twenty-four masonry prisms, including both grouted and hollow specimens, were tested to investigate the strain gradient effect on masonry compressive strength. Results showed that a reduction in load capacity as a result of an increase in eccentricity is more significant for grouted prisms than for their hollow counterparts. At a relatively large eccentricity to thickness ratio, e/t, hollow prisms attained a higher ultimate load than grouted prisms. Compressive stresses calculated at the extreme fibre using linear elastic analysis showed that the strain gradient effect increases with an increase in the eccentricity for grouted prisms, whereas the increase is marginal for hollow prisms. Coefficients for the equivalent stress distribution block, based on experimental stress–strain curves, were obtained for prisms under eccentric loading. An evaluation of the rectangular stress block used in both the American design code and Canadian design standard showed that the rectangular stress block provides an adequate and somewhat conservative estimate of masonry compressive strength and this conservatism increases as the strain gradient effect increases.Key words: masonry, strain gradient, eccentricity, compression, prisms, rectangular stress block, code, standard.
Study of crumb rubber materials as paving asphalt modifiers
Authors: MacLeod Daryl , Ho Susanna , Wirth Ryan , Zanzotto Ludo
Published: December 2007

Waste tire crumb rubber materials (CRM) were used to modify paving asphalts. The mixing time, hot-storage stability, Superpave grades, pumping and handling properties, phase separation tests, and repeated creep properties of the modified asphalts were studied using base asphalts of different hardness. Applying the Long-Term Pavement Performance (LTPP) program and the Transportation Association of Canada (TAC) model, optimal levels of CRM and suitable base asphalts were selected for the climatic conditions of Lethbridge, Alberta, Canada. High-temperature grade bumping protocol, regarding traffic volume and speed, was also considered. With joint efforts from the Tire Recycling Management Association of Alberta (TRMA), Husky Energy, and the City of Lethbridge, three test sections in different Lethbridge locations with various traffic volumes were paved from the years 2003 to 2005. So far, the City of Lethbridge is pleased with the initial performance of the test sections.Key words: waste tire, crumb rubber materials (CRM), paving asphalt, recycled, modification, Superpave, repeated creep, field test.
Seismic hazard estimates for sites in the stable Canadian craton
Authors: Atkinson Gail M , Martens Scott N
Published: December 2007

We address the challenging and economically important problem of seismic hazard estimation at low probabilities for stable cratonic regions such as central Canada which are characterized by very low seismicity rates. At low probabilities, large uncertainties in the seismicity rates result in calculated seismic hazards that are not negligible for practical purposes and may have significant implications for design and retrofit of critical structures such as hydroelectric and tailings dams. We examine the statistics of earthquake magnitude recurrence in such regions and their implications for hazard estimates at low probabilities. Recommendations for low-probability ground motions are provided that are related to the design life of the facilities.Key words: seismic hazard, earthquake, uniform hazard spectrum, stable interior craton, central Canada, dam.
Bioactivity-guided isolation of the active compounds from Rosa nutkana and quantitative analysis of ascorbic acid by HPLCThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Jovel Eduardo M. , Zhou Xi Ling , Ming Dong Sheng , Wahbe Tanya R. , Towers G.H. Neil
Published: December 2007

Rosa nutkana Presl. (Rosaceae) is distributed abundantly throughout central and southern areas of British Columbia, Canada. Aboriginal people in the Pacific Northwest have traditionally used R. nutkana as a food, medicine, and source of cultural material. The methanolic extract of the fruits of R. nutkana was previously found to have inhibitory activity against methicillin-resistant Staphylococcus aureus (MRSA). In our study, bioactivity-guided fractionation of the methanol extract from R. nutkana led to the isolation of the following 10 compounds: (i) tormentic acid, (ii) euscaphic acid, (iii) ursolic acid, (iv) maslinic acid, (v) quercetin, (vi) catechin gallate, (vii) quercetin-3-O-glucoside, (viii) 1,2,3,4,6-penta-O-galloyl-β-d-glucoside, (ix) l-ascorbic acid (vitamin C), and (x) 1,6-digalloyl-β-d-glucoside. Structures were elucidated by ultraviolet, infrared, mass spectrometry, and nuclear magnetic resonance data, as well as by comparison with those of the literature. The compounds quercetin, catechin gallate, quercetin-3-O-glucoside, 1,2,3,4,6-penta-O-galloyl-β-d-glucoside, and 1,6-digalloyl-β-d-glucoside exhibited weak antibacterial activity against MRSA. Our research demonstrates the value of traditional knowledge held by Aboriginal people in the Pacific Northwest with respect to uses of R. nutkana. Some described uses in the ethnobotanical literature correspond to activities observed under laboratory conditions. Further work on British Columbia Rosa spp. may contribute to identifying other potential therapeutic uses.
Studies on antihypertensive and antispasmodic activities of Andropogon muricatus Retz.This article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Gilani Anwar H. , Shah Abdul J. , Janbaz Khalid H. , Ahmed Shahida P. , Ghayur Muhammad N.
Published: December 2007

The aqueous-methanolic crude extract of Andropogon muricatus (Am.Cr) was investigated pharmacologically to determine some of its medicinal uses in cardiovascular and gastrointestinal disorders. A series of in vivo and in vitro studies were conducted to evaluate dose-dependent effects of Am.Cr on mean arterial pressure (MAP), cardiac and vascular contractions, and to further investigate the potential mechanism of action. Intravenous administration of Am.Cr (10–50 mg/kg) caused a fall (18%–56%) in MAP in normotensive rats under anesthesia. When tested in isolated guinea pig atria, Am.Cr (0.03–5.0 mg/mL) exhibited a cardiodepressant effect on the rate and force of spontaneous contractions. In isolated rabbit aorta, Am.Cr caused inhibition of K+ (80 mmol/L)-induced contractions at a lower concentration than of phenylephrine. In isolated rabbit jejunum preparations, Am.Cr (0.01–0.10 mg/mL) caused relaxation of spontaneous and high K+ (80 mmol/L)-induced contractions, suggesting that the spasmolytic effect is mediated possibly through calcium channel blockade (CCB). The CCB activity was confirmed when pretreatment of the tissue with Am.Cr (0.03–0.1 mg/mL) shifted the Ca2+ dose–response curves to the right, similar to that caused by verapamil. These data indicate that the blood pressure-lowering and spasmolytic effects of Am.Cr are mediated possibly through a calcium channel blocking activity. Phytochemical screening of Am.Cr revealed the presence of phenols, saponins, tannins, and terpenes, which may be responsible for the observed vasodilator, cardiodepressant, and antispasmodic activities. This study shows potential with respect to its medicinal use in cardiovascular and gut disorders.
Antiatherogenic activity of extracts of Argania spinosa L. pericarp: beneficial effects on lipid peroxidation and cholesterol homeostasisThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Berrougui Hicham , Cherki Mounia , Koumbadinga Geremy Abdull , Isabelle Maxim , Douville Jasmin , Spino Claude , Khalil Abdelouahed
Published: December 2007

Prevention of lipoprotein oxidation by natural compounds may prevent atherosclerosis via reducing early atherogenesis. In this study, we investigated for the first time the beneficial properties of methanolic extract of argania pericarp (MEAP) towards atherogenesis by protecting human low-density lipoprotein (LDL) against oxidation while promoting high-density lipoprotein (HDL)-mediated cholesterol efflux. By measuring the formation of malondialdehyde (MDA) and conjugated diene as well as the lag phase and the progression rate of lipid peroxidation, the MEAP was found to possess an inhibitory effect. In addition, MEAP reduced the rate of disappearance of α-tocopherol as well as the apoB electrophoretic mobility in a dose-dependent manner. These effects are related to the free radical scavenging and copper-chelating effects of MEAP. In terms of cell viability, MEAP has shown a cytotoxic effect (0–40 μg/mL). Incubation of3H-cholesterol-loaded J774 macrophages with HDL in the presence of increasing concentrations of MEAP enhanced HDL-mediated cholesterol efflux independently of ABCA1 receptor pathways. Our findings suggest that argania seed pericarp provides a source of natural antioxidants that inhibit LDL oxidation and enhance cholesterol efflux and thus can prevent development of cardiovascular diseases.
Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot studyThis article is one of a selection of papers published in this special issue (part 1 of 2) on the Safety and Efficacy of Natural Health Products.
Authors: Hudson Craig , Hudson Susan , MacKenzie Joan
Published: December 2007

Until recently, intact protein that is rich in tryptophan was not seen as an alternative to pharmaceutical-grade tryptophan because protein also contains large neutral amino acids (LNAAs) that compete for transport sites across the blood–brain barrier. Recent evidence indicates that when deoiled gourd seed (a rich source of tryptophan with approximately 22 mg/g protein) is combined with glucose (a carbohydrate that reduces serum levels of competing LNAAs) a clinical effect similar to that of pharmaceutical-grade tryptophan is achieved. Objective and subjective measures of anxiety in those suffering from social phobia (also known as social anxiety disorder) were employed to measure changes in anxiety in response to a stimulus as part of a double-blind, placebo-controlled, crossover study with a wash-out period of 1 week between study sessions. Subjects were randomly assigned to start with either (i) protein-source tryptophan (deoiled gourd seed) in combination with carbohydrate or (ii) carbohydrate alone. One week after the initial session, subjects returned for a follow-up session and received the opposite treatment of that received at the first session. All 7 subjects who began the study completed the 2-week protocol. Protein-source tryptophan with carbohydrate, but not carbohydrate alone, resulted in significant improvement on an objective measure of anxiety. Protein-source tryptophan combined with a high glycemic carbohydrate is a potential anxiolytic to those suffering from social phobia.
Antidiabetic potential of oleanolic acid from Ligustrum lucidum Ait.This 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: Gao Dawei , Li Qingwang , Li Ying , Liu Zhihua , Liu Zhiwei , Fan Yusheng , Han Zengsheng , Li Jian , Li Kun
Published: December 2007

Ligustrum lucidum Ait. has been used in traditional Chinese medicine for over 1000 years because of its anti-tumor, antimutagenic, antidiabetic, and hepatoprotective properties. The aim of this study was to determine whether oleanolic acid (OA) is the principal active compound of L. lucidum responsible for its antidiabetic properties, and to examine its effect on the expression of thyroid hormones and insulin secretion, thus revealing the mechanism by which L. lucidum modulates insulin levels in diabetes. When rats with streptozotocin-induced diabetes were treated with OA (100 and 200 mg/kg body mass per day, for 40 days), the changes in blood glucose levels and in oral glucose tolerance tests showed that hypoglycemia was more pronounced in OA-treated groups than in the diabetic control rats, and that the levels of triglyceride, total cholesterol, and low-density lipoportein cholesterol in OA-treated rats were lower than those in the diabetic control rats, whose high-density lipoprotein cholesterol increased. OA-treated rats also gained weight, and exhibited increased serum insulin levels. In contrast, OA treatment did not effect the levels of thyroid hormone or TSH in rats with streptozotocin-induced diabetes. These results indicate that OA has hypoglycemic and hypolipidemic effects. OA treatment might stimulate insulin release, and consequently, results in the modulation of glucose levels and regulation of lipid metabolism.
Antidiabetic properties of polysaccharide- and polyphenolic-enriched fractions from the brown seaweedAscophyllum nodosumThis 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: Zhang Junzeng , Tiller Christa , Shen Jingkai , Wang Can , Girouard Gabrielle S. , Dennis Dorothy , Barrow Colin J. , Miao Mingsan , Ewart H. Stephen
Published: December 2007

We screened seaweed species from Atlantic Canada for antidiabetic activity by testing extracts for α-glucosidase inhibitory effect and glucose uptake stimulatory activity. An aqueous ethanolic extract of Ascophyllum nodosum was found to be active in both assays, inhibiting rat intestinal α-glucosidase (IC50= 77 μg/mL) and stimulating basal glucose uptake into 3T3-L1 adipocytes during a 20-minute incubation by about 3-fold (at 400 μg/mL extract). Bioassay-guided fractionation of the A. nodosum extract showed that α-glucosidase inhibition was associated with polyphenolic components in the extract. These polyphenolics, along with other constituents appeared to be responsible for the stimulatory activity on glucose uptake. However, attempts to further concentrate this activity through fractionation techniques were unsuccessful. A crude polyphenol extract (PPE), an enriched polyphenolic fraction (PPE-F1) and a polysaccharide extract (PSE) were prepared from commercial A. nodosum powder and administered to streptozotocin-diabetic mice for up to 4-weeks by daily gavage at 200 mg/kg body mass. PPE and PPE-F1 improved fasting serum glucose level in diabetic mice; however, the effect was only statistically significant at day 14. In addition, PPE-F1 was shown to blunt the rise in blood glucose after an oral sucrose tolerance test in diabetic mice. Mice treated with PPE and PPE-F1 had decreased blood total cholesterol and glycated serum protein levels compared with untreated diabetic mice, whereas PPE also normalized the reduction in liver glycogen level that occurred in diabetic animals. All 3 A. nodosum preparations improved blood antioxidant capacity.
Senecio latifolius induces in vitro hepatocytotoxicity in a human cell lineThis 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: Neuman Manuela G. , Jia Angela Y. , Steenkamp Vanessa
Published: December 2007

The objectives of this study were twofold: (i) to determine the mechanism(s) of Senecio -induced toxicity in human hepatoblastoma cells (HepG2) in vitro and whether such toxicity could be prevented using N-acetyl-cysteine (NAC), and (ii) to evaluate whether caspases are involved in Senecio-induced apoptosis. Cells were treated with aqueous extracts of Senecio (10 mg·mL–1) with and without NAC. Cytotoxicity was determined by using the MTT assay. Total glutathione (GSH) was measured by using the Tietze assay. Cells were also treated with aqueous extracts of Senecio in the presence or absence of 50 μmol/L caspase-3 inhibitor (IDN) for 24 h. Apoptosis was determined by transmission electron microscopy, and DNA fragmentation was determined by ELISA and terminal dUTP nick-end labelling (TUNEL). Senecio produced cytotoxicity and depleted GSH in a concentration- and time-dependent manner. A significant depletion in GSH was observed after 15 min (p < 0.001 vs. control), whereas significant cytotoxicity was only observed after 3 h (p < 0.001 vs. control). Treatment with NAC prevented Senecio-induced GSH depletion and resulted in a significant decrease in Senecio-induced cytotoxicity (p < 0.001 vs. NAC-untreated cells). Treatment with Senecio for 24 h resulted in 22% ± 2.5% (p < 0.001) apoptosis (vs. control). Pretreatment with 50 μmol caspase inhibitor reduced Senecio-induced apoptosis significantly (vs. non-exposed to IDN) (12% ± 1.5%; p < 0.05). Our results suggest the mechanism of Senecio-induced cytotoxicity in HepG2 cells in vitro involves depletion of cellular GSH. Cytotoxicity is reduced by supplementation with NAC, which thus prevents GSH depletion. Caspase activation is involved in Senecio-induced apoptosis.
Adjuvant activities of saponins from the root of Polygala senega L.This 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: Katselis Georgios S. , Estrada Alberto , Gorecki Dennis K.J. , Barl Branka
Published: December 2007

Eight pure triterpenoid saponin compounds isolated from the root of Polygala senega L., a plant indigenous to the Canadian prairies, were evaluated for their immunological activity in mouse models. The specific antibody responses of the IgG2asubclass increased significantly when isolated P. senega saponins were used as adjuvants in the immunization of mice with OVA antigen. In addition, increased IL-2 levels were observed in spleen cell cultures from P. senega saponin-immunized mice after in vitro secondary antigen stimulation. The saponins were tested for their toxicity in mice by using a haemolytic activity assay and found to be less toxic than Quillaja saponaria saponins that have long been used as adjuvants in vaccine formulations. This study has shown the potential of P. senega saponins to be considered as a natural source of vaccine adjuvants with biological activity equivalent to the current commercially available saponin adjuvants.
Homocysteine stimulates NADPH oxidase-mediated superoxide production leading to endothelial dysfunction in rats
Authors: Edirimanne Vathsala E.R. , Woo Connie W.H. , Siow Yaw L. , Pierce Grant N. , Xie Jiu Y. , O Karmin
Published: December 2007

Elevation of blood homocysteine (Hcy) levels (hyperhomocysteinemia) is a risk factor for cardiovascular disorders. We previously reported that oxidative stress contributed to Hcy-induced inflammatory response in vascular cells. In this study, we investigated whether NADPH oxidase was involved in Hcy-induced superoxide anion accumulation in the aorta, which leads to endothelial dysfunction during hyperhomocysteinemia. Hyperhomocysteinemia was induced in rats fed a high-methionine diet. NADPH oxidase activity and the levels of superoxide and peroxynitrite were markedly increased in aortas isolated from hyperhomocysteinemic rats. Expression of the NADPH oxidase subunit p22phox increased significantly in these aortas. Administration of an NADPH oxidase inhibitor (apocynin) not only attenuated aortic superoxide and peroxynitrite to control levels but also restored endothelium-dependent relaxation in the aortas of hyperhomocysteinemic rats. Transfection of human endothelial cells or vascular smooth muscle cells with p22phox siRNA to inhibit NADPH oxidase activation effectively abolished Hcy-induced superoxide anion production, thus indicating the direct involvement of NADPH oxidase in elevated superoxide generation in vascular cells. Taken together, these results suggest that Hcy-stimulated superoxide anion production in the vascular wall is mediated through the activation of NADPH oxidase, which leads to endothelial dysfunction during hyperhomocysteinemia.
Soil, human society and the environment
Authors: Blum W. E. H. , Warkentin B. P. , Frossard E.
Published: December 2007

Soils, forming the top layer of the Earth's crust, are a mixture of mineral particles, organic matter, water, air and living organisms. Processes between these components perform vital functions within ecosystems. The soil forms an interface between the geosphere, the biosphere, the hydrosphere and the atmosphere, and is a largely non-renewable resource.
Ugolini & Warkentin
show the fruitful relationships which geology and soil science have established since the birth of soil science, and how these two disciplines together could contribute to solve future problems.

The dynamic soil system delivers functions and services vital for human societies and the environment. Soil is the basis for food and biomass production, and plays a central role as a habitat for biota and as a gene pool. Moreover, it stores, filters, buffers and transforms a large variety of substances, including water, inorganic and organic compounds, and is a major sink and source for greenhouse gases. Soil provides raw materials for human use. It also serves as the basis for human activities (landscape and heritage) and for our technical and socio-economic infrastructure, delivering materials for their implementation and maintenance.
Soils as sources and sinks of greenhouse gases
Authors: Leifeld Jens
Published: December 2007

Soils annually emit between 6.8 and 7.9 Gt CO
2
equivalents, mainly as CH
4
from intact peatlands and from rice agriculture; as N
2
O from unmanaged and managed soils; and as CO
2
from land-use change. Methane emissions attributable to other wetlands add another 1.6–3.8 Gt CO
2
equivalents. From a global standpoint, N
2
O from unmanaged soils and CH
4
from peatlands and other wetlands make soils naturally net greenhouse gas emitters. In addition, the storage of carbon in soils and the fluxes of CH
4
and N
2
O have been changed by anthropogenic effects towards emission rates 52 to 72% above those under natural conditions before the dawn of intensive agriculture and land-use change. Land-use changes on mineral soils induced most of the recorded losses of soil organic matter (SOM), but there is evidence that proper agricultural management of soil resources is able to recover some of these losses and to maintain soil functions. However, the discrepancy between so-called ‘sequestration potentials’ and the measures already adopted is amazingly large. Globally, only about 5% of the cropped areas is managed according to practices such as no tillage or organic farming. The contribution of soil loss by erosion, desertification and sealing to global oxidative SOM losses is uncertain; however, in the case of soil erosion, it is considered to be a major factor in global SOM decline. Mitigation options calculated for SOM restoration, reduced CH
4
and N
2
O emissions are able to alleviate mean annual emissions by 1.2 to 2.9 Gt CO
2
equivalents, mainly as a result of carbon sequestration, which is the most efficient measure for the next few decades. In the longer term, however, the large potential for reducing CH
4
and N
2
O emissions outweigh the finite capacity of soils to recover C. Integrated assessment of net greenhouse-gas fluxes is key for evaluating management practices aimed at reducing overall emissions. From the viewpoint of climate change and taking into consideration the mean fluxes of CO
2
, CH
4
and N
2
O, peatland protection is more favourable than peatland cultivation in the long term. The most important gaps in our understanding appear to be with regard to estimating fluxes along with soil erosion and desertification processes, in the extent of peatland cultivation; the role of black carbon formation, natural ‘background’ sequestration rates of undisturbed soils; and the net response of soils, particularly in cold regions, to global warming. With regard to the societal perception of soil contributing to the global cycling of greenhouse gases, it is important to emphasize that significant proportions of the emissions are inevitably linked to intensive agriculture.
Understanding of a soil system derived from a single bed-rock, for improved vineyard management in Southern France
Authors: Dosso M. , Philippon O. , Ruellan A.
Published: December 2007

The ‘Massif de La Clape’ in Southern France is a calcareous hill with a semi-arid Mediterranean climate. All the agricultural lands are under vineyards managed by different châteaux. The objective of this work was to understand the soil system of Château X to solve a problem of vineyard mortality and to show how the exceptional variability of the soil conditions could be taken into account for optimal vineyard management. The soils of Château X are derived from sandstone that fills a basin of about 40 ha, surrounded by a calcareous formation. The study of the soil system showed the presence of four soil domains, two located at the top of the basin and mainly derived from eluviation, and two located at the bottom of the basin, which are mainly derived from illuviation. The domain located at the very bottom of the basin showed an accumulation of swelling clays in its Bt
M
horizon. The zones of highest vine mortality were located at the bottom of the basin, on the soil with the Bt
M
horizon. This mortality was explained by the strong discontinuity between the E and the Bt
M
horizons, with the accumulation of Cu at toxic concentrations as a consequence of lateral water flows. In this soil, root growth was hindered by the high bulk density of the Bt
M
horizon. In order to solve the problem of vine mortality and manage the vineyard according to the different soil conditions observed in the topo-sequence, several proposals are made.
Cultural soilscapes
Authors: Wells E. C.
Published: December 2007

While soil is normally studied as the outcome of natural geological and chemical processes, soil research by archaeologists, geographers and other social scientists focuses on the human behavioural dimensions of soil formation. As a result, ‘cultural soilscape’ is an analytical concept common to both Earth and social sciences that encourages a more holistic, transdisciplinary approach to studying soil formation processes. This paper introduces the concept of cultural soilscape and reviews important archaeological work on this theme over the past decade.