bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective and Pathologic Roles of the Immune Response to Mouse Hepatitis Virus Type 1: Implications for Severe Acute Respiratory Syndrome
Authors: Khanolkar Aaruni , Hartwig Stacey M. , Haag Brayton A. , Meyerholz David K. , Epping Lecia L. , Haring Jodie S. , Varga Steven M. , Harty John T.
Published: July 2009

Intranasal mouse hepatitis virus type 1 (MHV-1) infection of mice induces lung pathology similar to that observed in severe acute respiratory syndrome (SARS) patients. However, the severity of MHV-1-induced pulmonary disease varies among mouse strains, and it has been suggested that differences in the host immune response might account for this variation. It has also been suggested that immunopathology may represent an important clinical feature of SARS. Little is known about the host immune response to MHV-1 and how it might contribute to some of the pathological changes detected in infected mice. In this study we show that an intact type I interferon system and the adaptive immune responses are required for controlling MHV-1 replication and preventing morbidity and mortality in resistant C57BL/6J mice after infection. The NK cell response also helps minimize the severity of illness following MHV-1 infection of C57BL/6J mice. In A/J and C3H/HeJ mice, which are highly susceptible to MHV-1-induced disease, we demonstrate that both CD4 and CD8 T cells contribute to morbidity during primary infection, and memory responses can enhance morbidity and mortality during subsequent reexposure to MHV-1. However, morbidity in A/J and C3H/HeJ mice can be minimized by treating them with immune serum prior to MHV-1 infection. Overall, our findings highlight the role of the host immune response in contributing to the pathogenesis of coronavirus-induced respiratory disease.
Characterization of a Novel Flavivirus from Mosquitoes in Northern Europe That Is Related to Mosquito-Borne Flaviviruses of the Tropics
Authors: Huhtamo Eili , Putkuri Niina , Kurkela Satu , Manni Tytti , Vaheri Antti , Vapalahti Olli , Uzcátegui Nathalie Y.
Published: July 2009

A novel flavivirus was isolated from mosquitoes in Finland, representing the first mosquito-borne flavivirus from Northern Europe. The isolate, designated Lammi virus (LAMV), was antigenically cross-reactive with other flaviviruses and exhibited typical flavivirus morphology as determined by electron microscopy. The genomic sequence of LAMV was highly divergent from the recognized flaviviruses, and yet the polyprotein properties resembled those of mosquito-borne flaviviruses. Phylogenetic analysis of the complete coding sequence showed that LAMV represented a distinct lineage related to the
Aedes
sp.-transmitted human pathogenic flaviviruses, similarly to the newly described Nounané virus (NOUV), a flavivirus from Africa (S. Junglen et al., J. Virol. 83:4462-4468, 2009). Despite the low sequence homology, LAMV and NOUV were phylogenetically grouped closely, likely representing separate species of a novel group of flaviviruses. Despite the biological properties preferring replication in mosquito cells, the genetic relatedness of LAMV to viruses associated with vertebrate hosts warrants a search for disease associations.
Anterograde Spread of Herpes Simplex Virus Type 1 Requires Glycoprotein E and Glycoprotein I but Not Us9
Authors: McGraw Helen M. , Awasthi Sita , Wojcechowskyj Jason A. , Friedman Harvey M.
Published: July 2009

Anterograde neuronal spread (i.e., spread from the neuron cell body toward the axon terminus) is a critical component of the alphaherpesvirus life cycle. Three viral proteins, gE, gI, and Us9, have been implicated in alphaherpesvirus anterograde spread in several animal models and neuron culture systems. We sought to better define the roles of gE, gI, and Us9 in herpes simplex virus type 1 (HSV-1) anterograde spread using a compartmentalized primary neuron culture system. We found that no anterograde spread occurred in the absence of gE or gI, indicating that these proteins are essential for HSV-1 anterograde spread. However, we did detect anterograde spread in the absence of Us9 using two independent Us9-deleted viruses. We confirmed the Us9 finding in different murine models of neuronal spread. We examined viral transport into the optic nerve and spread to the brain after retinal infection; the production of zosteriform disease after flank inoculation; and viral spread to the spinal cord after flank inoculation. In all models, anterograde spread occurred in the absence of Us9, although in some cases at reduced levels. This finding contrasts with gE- and gI-deleted viruses, which displayed no anterograde spread in any animal model. Thus, gE and gI are essential for HSV-1 anterograde spread, while Us9 is dispensable.
A Simian Immunodeficiency Virus-Infected Macaque Model To Study Viral Reservoirs That Persist during Highly Active Antiretroviral Therapy
Authors: Dinoso Jason B. , Rabi S. Alireza , Blankson Joel N. , Gama Lucio , Mankowski Joseph L. , Siliciano Robert F. , Zink M. Christine , Clements Janice E.
Published: July 2009

The treatment of human immunodeficiency virus type 1 (HIV-1) infection with highly active antiretroviral therapy (HAART), a combination of three or more antiretroviral drugs, suppresses viremia below the clinical limit of detection (50 HIV-1 RNA copies/ml), but latently infected resting CD4
+
T cells serve as lifelong reservoirs, and low-level viremia can be detected with special assays. Recent studies have provided evidence for additional reservoirs that contribute to residual viremia but are not present in circulating cells. Identification of all the sources of residual viremia in humans may be difficult. These discoveries highlight the need for a tractable model system to identify additional viral reservoirs that could represent barriers to eradication. In this study, simian immunodeficiency virus (SIV)-infected pig-tailed macaques (
Macaca nemestrina
) were treated with four antiretroviral drugs to develop an animal model for viral suppression during effective HAART. Treatment led to a biphasic decay in viremia and a significant rise in levels of circulating CD4
+
T cells. At terminal infection time points, the frequency of circulating resting CD4
+
T cells harboring replication-competent virus was reduced to a low steady-state level similar to that observed for HIV-infected patients on HAART. The frequencies of resting CD4
+
T cells harboring replication-competent virus in the pooled head lymph nodes, gut lymph nodes, spleen, and peripheral blood were reduced relative to those for untreated SIV-infected animals. These observations closely parallel findings for HIV-infected humans on suppressive HAART and demonstrate the value of this animal model to identify and characterize viral reservoirs persisting in the setting of suppressive antiretroviral drugs.
Cowpox Virus Expresses a Novel Ankyrin Repeat NF-κB Inhibitor That Controls Inflammatory Cell Influx into Virus-Infected Tissues and Is Critical for Virus Pathogenesis
Authors: Mohamed Mohamed Ragaa , Rahman Masmudur M. , Rice Amanda , Moyer Richard W. , Werden Steven J. , McFadden Grant
Published: July 2009

Many pathogenic orthopoxviruses like variola virus, monkeypox virus, and cowpox virus (CPXV), but not vaccinia virus, encode a unique family of ankyrin (ANK) repeat-containing proteins that interact directly with NF-κB1/p105 and inhibit the NF-κB signaling pathway. Here, we present the in vitro and in vivo characterization of the targeted gene knockout of this novel NF-κB inhibitor in CPXV. Our results demonstrate that the vCpx-006KO uniquely induces a variety of NF-κB-controlled proinflammatory cytokines from infected myeloid cells, accompanied by a rapid phosphorylation of the IκB kinase complex and subsequent degradation of the NF-κB cellular inhibitors IκBα and NF-κB1/p105. Moreover, the vCpx-006KO virus was attenuated for virulence in mice and induced a significantly elevated cellular inflammatory process at tissue sites of virus replication in the lung. These results indicate that members of this ANK repeat family are utilized specifically by pathogenic orthopoxviruses to repress the NF-κB signaling pathway at tissue sites of virus replication in situ.
The Spike Protein of Murine Coronavirus Regulates Viral Genome Transport from the Cell Surface to the Endoplasmic Reticulum during Infection
Authors: Zhu Hongqing , Yu Dongdong , Zhang Xuming
Published: July 2009

We observed that the nonfusogenic mouse hepatitis virus (MHV) strain MHV-2 reached a titer of ∼2 log
10
higher than that of the fusogenic strain A59 in astrocytoma DBT cells. To determine whether the spike protein is responsible for the difference, a recombinant virus, Penn-98-1, that contains the A59 genome with a spike from MHV-2 was used to infect DBT cells. Results showed that Penn-98-1 behaved like MHV-2, thus establishing a role for the spike protein in viral growth. The inverse correlation between viral fusogenicity and growth was further established in four different cell types and with a fusogenic mutant, the S757R mutant, derived from isogenic Penn-98-1. While both A59 and Penn-98-1 entered cells at similar levels, viral RNA and protein syntheses were significantly delayed for A59. Interestingly, when the genomic RNAs were delivered directly into the cells via transfection, the levels of gene expression for these viruses were similar. Furthermore, cell fractionation experiments revealed that significantly more genomic RNAs for the nonfusogenic MHVs were detected in the endoplasmic reticulum (ER) within the first 2 h after infection than for the fusogenic MHVs. Pretreatment of Penn-98-1 with trypsin reversed its properties in syncytium formation, virus production, and genome transport to the ER. These findings identified a novel role for the spike protein in regulating the uncoating and delivery of the viral genome to the ER after internalization.
Role of Oxysterol Binding Protein in Hepatitis C Virus infection
Authors: Amako Yutaka , Sarkeshik Ali , Hotta Hak , Yates John , Siddiqui Aleem
Published: July 2009

Hepatitis C virus (HCV) RNA genome replicates within the ribonucleoprotein (RNP) complex in the modified membranous structures extended from endoplasmic reticulum. A proteomic analysis of HCV RNP complexes revealed the association of oxysterol binding protein (OSBP) as one of the components of these complexes. OSBP interacted with the N-terminal domain I of the HCV NS5A protein and colocalized to the Golgi compartment with NS5A. An OSBP-specific short hairpin RNA that partially downregulated OSBP expression resulted in a decrease of the HCV particle release in culture supernatant with little effect on viral RNA replication. The pleckstrin homology (PH) domain located in the N-terminal region of OSBP targeted this protein to the Golgi apparatus. OSBP deletion mutation in the PH (ΔPH) domain failed to localize to the Golgi apparatus and inhibited the HCV particle release. These studies suggest a possible functional role of OSBP in the HCV maturation process.
Origin of Expression of the Herpes Simplex Virus Type 1 Protein U
S
1.5
Authors: Bowman J. Jason , Schaffer Priscilla A.
Published: July 2009

ICP22, an immediate-early protein of herpes simplex virus type 1 (HSV-1), is required for viral replication in nonpermissive cell types and for expression of a class of late viral proteins which includes glycoprotein C. An understanding of the mechanism of ICP22 function has been complicated by the coexpression of the full-length protein with an in-frame, C-terminus-specific protein, U
S
1.5. In this report, we confirm that the U
S
1.5 protein is a bona fide translation product since it is detected during infections with three laboratory strains and two low-passage clinical isolates of HSV-1. To clarify the expression patterns of the ICP22 and U
S
1.5 proteins, we examined their synthesis from plasmids in transient expression assays. Because previous studies had identified two different U
S
1.5 translational start sites, we attempted to determine which is correct by studying the effects of a series of deletion, nonsense, and methionine substitutions on U
S
1.5 expression. First, amino acids 90 to 420 encoded by the ICP22 open reading frame (ORF) migrated at the mobility of U
S
1.5 in sodium dodecyl sulfate-polyacrylamide gels. Second, introduction of a stop codon downstream of M90 ablated expression of both ICP22 and U
S
1.5. Finally, mutation of M90 to alanine (M90A) allowed expression of full-length ICP22 while dramatically reducing expression of U
S
1.5. Levels of U
S
1.5 but not ICP22 protein expression were also reduced in cells infected with an M90A mutant virus. Thus, we conclude that expression of IC22 and that of U
S
1.5 can occur independently of each other and that U
S
1.5 translation initiates at M90 of the ICP22 ORF.
Inhibition of Macrophage Activation by the Myxoma Virus M141 Protein (vCD200)
Authors: Zhang Leiliang , Stanford Marianne , Liu Jia , Barrett Catherine , Jiang Lei , Barclay A. Neil , McFadden Grant
Published: July 2009

The M141 protein of myxoma virus (MYXV) is a viral CD200 homolog (also called vOX-2) that inhibits macrophage activation in infected rabbits. Here, we show that murine myeloid RAW 264.7 cells became activated when infected with MYXV in which the M141 gene was deleted (vMyx-M141KO) but not with the parental wild-type MYXV. Moreover, transcript and protein levels of tumor necrosis factor and granulocyte colony-stimulating factor were rapidly upregulated in an NF-κB-dependent fashion in the RAW 264.7 cells infected with vMyx-M141KO. M141 protein is present in the virion and counteracts this NF-κB activation pathway upon infection with the wild-type MYXV. Our data suggest that upregulation of these classic macrophage-related proinflammatory cytokine markers following infection of myeloid cells with the M141-knockout MYXV is mediated via the rapid activation of the cellular NF-κB pathway.
Prion Infectivity in Fat of Deer with Chronic Wasting Disease
Authors: Race Brent , Meade-White Kimberly , Race Richard , Chesebro Bruce
Published: July 2009

Chronic wasting disease (CWD) is a neurodegenerative prion disease of cervids. Some animal prion diseases, such as bovine spongiform encephalopathy, can infect humans; however, human susceptibility to CWD is unknown. In ruminants, prion infectivity is found in central nervous system and lymphoid tissues, with smaller amounts in intestine and muscle. In mice, prion infectivity was recently detected in fat. Since ruminant fat is consumed by humans and fed to animals, we determined infectivity titers in fat from two CWD-infected deer. Deer fat devoid of muscle contained low levels of CWD infectivity and might be a risk factor for prion infection of other species.
Conventional Bone Marrow-Derived Dendritic Cells Contribute to Toll-Like Receptor-Independent Production of Alpha/Beta Interferon in Response to Inactivated Parapoxvirus Ovis
Authors: Siegemund Sabine , Hartl Andrea , von Buttlar Heiner , Dautel Franziska , Raue Rüdiger , Freudenberg Marina A. , Fejer György , Büttner Mathias , Köhler Gabriele , Kirschning Carsten J. , Sparwasser Tim , Alber Gottfried
Published: July 2009

Parapoxvirus ovis (PPVO) is a member of the
Poxviridae
family and belongs to the genus
Parapoxvirus
. It displays only limited homology with orthopoxviruses and has some molecular features such as an unusual high GC content distinct from orthopoxviruses. Inactivated PPVO (iPPVO) displays strong immunostimulatory capacities mediating antiviral activity in vivo. The role of dendritic cells (DC) and the pattern recognition receptors and signaling requirements responsible for immunostimulation by iPPVO are unknown. We demonstrate here that bone marrow-derived plasmacytoid DC (BM-pDC) and bone marrow-derived conventional DC (BM-cDC) secrete alpha/beta interferon (IFN-α/β) in response to iPPVO. Furthermore, iPPVO induces tumor necrosis factor alpha (TNF-α) and interleukin-12/23p40 (IL-12/23p40) release and major histocompatibility complex class II (MHC-II), MHC-I, and CD86 upregulation by bone marrow-derived DC (BMDC). After engulfment, iPPVO is located in endosomal compartments and in the cytosol of BMDC. iPPVO elicits IFN-α/β by Toll-like receptor (TLR)-independent pathways in BM-cDC, since IFN-α/β release does not require myeloid differentiation primary response gene 88 (MyD88) or TIR-domain containing adaptor protein inducing interferon (TRIF). In contrast, iPPVO-induced TNF-α release and enhanced expression of MHC-I and CD86 but not of MHC-II by BMDC chiefly requires MyD88 but not TLR2 or TLR4. Induction of IFN-α by iPPVO in BM-cDC occurred in the absence of IFN regulatory factor 3 (IRF3) but required the presence of IRF7, whereas iPPVO-triggered IFN-β production required the presence of either IRF7 or IRF3. These results provide the first evidence that iPPVO mediates its immunostimulatory properties by TLR-independent and TLR-dependent pathways and demonstrate an important role of cDC for IFN-α/β production.
Rational Approximations to Solutions of the VPA Equations
Authors: Evans Geoffrey T.
Published: July 2009

Solutions of the survival equation used in virtual population analysis can be well approximated by quotients of polynomials. This form of approximation may offer a good tradeoff between accuracy and fast computation.
Predicting the Return Migration Routes of the Fraser River Sockeye Salmon (Oncorhynchus nerka)
Authors: Xie Liusen , Hsieh William W.
Published: July 2009

The Johnstone Strait diversion rate (i.e. the percentage of homeward migrating Fraser River sockeye salmon (Oncorhynchus nerka) travelling around Vancouver Island via the northern route of Johnstone Strait) is statistically predicted using the March values of the Kains Island sea surface temperature T and the Fraser River runoff R. The prediction formula incorporates nonlinear terms such as T2 and RT, as well as the diversion rate 2 yr ago. We tested the forecasting performance by constructing a prediction formula using only data from 1953–78, and making predictions for 1979–88. The mean absolute error of our prediction of the diversion rate was 8% which compared favourably with the prediction by a linear temperature scheme and a linear runoff scheme where the errors were respectively 13 and 29%. Unlike the latter two schemes where T and R data from April–June are needed, our scheme with the use of data no later than March allows much earlier forecasts to be made.
Fate of Coho Salmon (Oncorhynchus kisutch) Carcasses in Spawning Streams
Authors: Cederholm C. J. , Houston D. B. , Cole D. L. , Scarlett W. J.
Published: July 2009

We examined the levels of retention and utilization of 945 coho salmon (Oncorhynchus kisutch) carcasses released experimentally into seven spawning streams on the Olympic Peninsula, Washington. Most carcasses were retained in the streams and in adjacent forests, few were flushed beyond 600 m. Organic debris caught and held many carcasses. Much of the fish mass was consumed by 22 species of mammals and birds. The distances that carcasses drifted appeared to be related directly to the occurrence of freshets and inversely to debris load and carnivore scavenging. The capacity of many streams and rivers to retain carcasses has probably been reduced by human activities. The importance of coho carcasses to populations of carnivores and to the dynamics of lotic food webs merits additional study.
A Dynamic Approach to Catch–Effort Data Analysis using a New Concept: the Inertia of the Stock
Authors: Lleonart Jordi , Salat Jordi
Published: July 2009

The steady-state hypothesis assumed in the classical production models, or catch–effort data analysis, is unrealistic in normal fisheries, and dynamic production models have been developed in order to avoid such a hypothesis. In this paper a dynamic approach to production models is presented. This approach does not alter the classical equilibrium curves. It permits us to estimate their parameters from nonequilibrium fisheries data and to describe the trajectories followed by the fishery in the catch–effort plane, so it predicts catches, it has a 1-yr memory and introduces a new meaningful parameter, called inertia, representing the stock's resistance to changes in fishing effort. The approach is applied to two different sets of historical catch–effort data, and compared with the classical one showing an improvement in the fit.
Development of Benthic Algal Assemblages Subjected to Differing Near-Substrate Hydrodynamic Regimes
Authors: Reiter Michael A.
Published: July 2009

Recent research concerning benthic algae in streams suggests that the near-substrate hydrodynamic regime may affect the composition of benthic algal assemblages. Algae from local streams were allowed to colonize laboratory flumes containing substrates of different sizes under two velocity regimes to determine whether benthic algal assemblages were affected by substrate size or hydrodynamics. While all hydrodynamic parameters except for local velocity diverged among flumes with different substrate sizes, cell counts per unit area of substrate and the relative proportions of different forms of algae remained similar overall. Much of the similarity appears to be attributable to the dominant filamentous algae. "Blooms" of one or two species were detected on occasion, but did not affect overall similarity (though they may affect local recolonization). The results, if extrapolated, suggest that hydrodynamic conditions alone may not be responsible for the variation in algal assemblages seen in the field, and that the morphological form of the alga may be more important than the species of alga when determining its response to hydrodynamic conditions.
Spatial and Temporal Variation in a Population of Freshwater Mussels in shell Lake, N.W.T.
Authors: Bailey Robert C. , Green Roger H.
Published: July 2009

A population of Anodonta grandis (Bivalvia; Unionidae) in a small Arctic lake was sampled in 1973 and 1986. In both of the years sampled there were about 14 times more mussels in deep (> 1.5 m) water than in shallow Water There was a decline in growth rate, a shift towards an older age structure, and a drop in population density from 2.3 to 0.65 animals per∙m−2 between 1973 and 1986. This pattern is consistent with an hypothesis of anthropogenic impact. The limitations of such an interpretation are discussed.
Stream Temperatures and Inter-Annual Variability in the Emigration Timing of Coho Salmon (Oncorhynchus kisutch) Smolts and fry and Chum Salmon (O. Keta) Fry from Carnation Creek, British Columbia
Authors: Holtby L. Blair , McMahon Thomas E. , Scrivener J. Charles
Published: July 2009

Variability in average stream temperatures between peak spawning and fry emergence accounted for 82 and 77% of the variance in the median emigration date of fry of chum (Oncorhynchus keta) and coho salmon (O. kisutch) respectively over a 9 to 10-yr period. The modeled relationships were indistinguishable from laboratory models that predicted time to maximum alevin wet weight. Variability in stream temperatures during the spring accounted for 60% of the variability in the median date of coho smolt emigration. As stream temperatures increased, the predicted thermal summations required for emigration were nearly constant for coho salmon fry, increased moderately for chum salmon fry and increased strongly for coho salmon smolts The duration of the emigration period also differed between the groups: 50% of the chum salmon fry emigrated over a 1-wk period compared with a 2- to 3-wk period for coho salmon fry and smolts. We speculate that the emigration timing —temperature relationships and timing of adult spawning represent adaptations for synchronizing emigration with "windows of opportunity" in the ocean or stream. The windows are of different widths and levels of predictability for coho and chum salmon fry and coho salmon smolts.
Estimating the Juvenile Survival Rate of Male Northern Fur Seals (Callorhinus ursinus)
Authors: Trites Andrew W.
Published: July 2009

Three methods for estimating the survival rate of juvenile northern fur seals (Callorhinus ursinus) are developed from the earlier works of Chapman, Smith and Polacheck and Lander. Each of the methods I propose divides the estimated number of males alive at 2 yr of age by the estimated number of pups born in their year class. The number of surviving juveniles are reconstructed by back calculation using the number of males killed during the commercial harvest and the subsequent counts of bulls. The three methods differ in their assumptions concerning subadult survival and escapement from the harvest, although all produce similar estimates when applied to the St. Paul Island fur seals. These new estimates of juvenile survival (1950–80) are strongly correlated with the ratio of cohort kill to pup production and with estimates from the currently-used Lander procedure. This is because the harvest morality of males is large compared with natural morality. The new methods perform acceptably over a wider class of data than Lander's. Their greatest advantage over current procedures is that they provide a better insight into the reliability of the survival estimates they produce.
The Decline and Fall of the Pribilof Fur Seal (Callorhinus ursinus): A Simulation Study
Authors: Trites Andrew W. , Larkin Peter A.
Published: July 2009

A mathematical model incorporating the basic life history features of the North Pacific fur seal (Callorhinus ursinus) approximated the decline of the Pribilof Islands population by reconstructing pup estimates and counts of adult males over the period 1950 to 1987. Simulation results suggest that commercial female harvesting and a series of poor juvenile survival rates were responsible for causing and maintaining the observed decline in pup production on St. Paul Island from 1956 to 1970. A more recent drop in pup production since 1976 is also attributed to poor juvenile survival, but with the addition of higher natural mortalities of adult females. It appears that the natural mortality of adult females may have increased by 2 to 5% beginning in the mid 1970s. We suspect reductions in the fur seal food base and entanglement-related mortality associated with commercial fishing in the North Pacific are contributing to the current decline, although neither possibility has yet been clearly demonstrated.
Use of White Sucker (Catostomus commersoni) Populations to Assess the Health of Aquatic Ecosystems Exposed to Low-Level Contaminant Stress
Authors: Munkittrick K. R. , Dixon D. G.
Published: July 2009

There is a need to develop inexpensive methods for evaluating contaminant impacts on aquatic ecosystems. This paper describes a simple, rapid, cost-effective mechanism for the in situ assessment of toxicant impact on fish populations. The framework assumes that changes in the death or birth rate, or alterations in the availability of food or habitat, are associated with characteristic responses of white sucker (Catostomus commersoni) populations. The responses have been grouped into five main patterns based on the population characteristics of mean age, fecundity, and condition factor. Populations which are growing, reproducing, and surviving at rates which are indistinguishable from a reference (control) population are considered to be free from adverse chemical effects. Analysis of published studies showed that white sucker populations responsed to several classes of environmental stressors in a predictable fashion and the framework suggested areas for follow-up study. The framework does have several limitations and is dependent upon the selection and appropriate sampling of a comparable reference population. Requirements for further development are discussed.
Long-Term Trends in Lake Water pH and Metal Concentrations Inferred from Diatoms and Chrysophytes in Three Lakes near Sudbury, Ontario
Authors: Dixit Aruna S. , Dixit Sushil S. , Smol John P.
Published: July 2009

Diatom valves and chrysophyte scales were analyzed in sediment cores to assess historical (post-1860) and recent (since 1970) trends in lake water pH, total [Al], and [Ni] in Lumsden, George, and Acid lakes (Killarney Provincial Park, Ontario). Although acidification in Lumsden and Acid lakes started in the 1930s, rapid acidification only occurred since the 1960s. As lake water pH declined, inferred [Al] greatly increased causing the extirpation of the sport fisheries. In nearby George Lake, acidification started in the 1920s, and inferred lake water pH declined about 0.5 of a pH unit by 1960. The fish community in George Lake survived where the inferred acidification was less severe than Acid and Lumsden lakes. As in previous paleolimnological studies, chrysophytes generally indicate earlier and more marked acidification trajectories when compared with trends inferred from diatoms, probably because the vernal blooming and euplanktonic chrysophytes are tracking spring pH depressions. Although all three lakes have acidified and metal concentrations have increased during this century, our study provides evidence that these lakes, located as far as 60 km away from Sudbury, are showing signs of biological and chemical recovery as a result of recent reductions in SO2emissions from the Sudbury smelters.
Landsat Views of Sudbury (Canada) Area Acidic and Nonacidic Lakes
Authors: Pitblado J. Roger
Published: July 2009

Multivariate statistical procedures are used to establish empirical associations between acidity, visual lake water colour, dissolved organic carbon (DOC) concentrations, and Landsat-5 Thematic Mapper (TM) radiance data. Acidic lakes in an area northeast of Sudbury (Canada) are characterized by their clear, blue colours and very low DOC. With a subjective, three-class water colour grouping, 92% of the study lakes were correctly classified using TM data. Further, it is shown that DOC, the major component of water colour in this area, can be predicted within 1 mg/L of observed concentrations using TM data (multiple r = 0.93, P < 0.01). By deriving interrelationships between pH levels, water colour, and DOC, Landsat data provide a means to discriminate and map the acidic and nonacidic lakes of the study area. Examination of the reflectance characteristics of a single acidic lake (Bowland Lake) that has undergone neutralization suggests that Landsat data may be used to detect optical changes over time. However, the capability for monitoring the temporal dimension of lake acidification using satellite data has yet to be established.
Benthic Macroinvertebrate Changes in Lakes near Sudbury, Ontario, following a Reduction in Acid Emissions
Authors: Griffiths Ronald W. , Keller W.
Published: July 2009

Benthic macroinvertebrates were sampled from three lake basins before and after a reduction in acidity, a result of reduced acid emissions from the smelting industry in Sudbury, Ontario. The number of taxa and macroinvertebrate density were greater in the later surveys of the lakes than expected by chance alone. Species richness and macroinvertebrate density were higher in all littoral habitats and in profundal habitats of two lake basins. Species richness showed little change and macroinvertebrate density was lower in the profundal habitat of the third lake basin. Increased survival, probably as a result of reduced chemical toxicity, best accounted for the higher species richness and benthic density. Trout predation, through a numerical response, probably masked these responses in the profundal habitat of the third lake basin because the refuge area from predation (i.e. region of the hypolimnion low in dissolved oxygen) was small. These data indicate that biological recovery of industrially acidified lakes is possible solely by reducing emissions, provided that recolonizing species are not locally extinct.
Estimated Impacts of SO2 Emissions from Sudbury Smelters on Ontario's Sportfish Populations
Authors: Matuszek John E. , Wales Donna L. , Gunn John M.
Published: July 2009

Impacts of acidification on the major sportfish species in Ontario (lake trout (Salvelinus namaycush), brook trout (S. fontinalis), smallmouth bass (Micropterus dolomieu), and walleye (Stizostedion vitreum)) were estimated from the results of extensive water quality surveys conducted during the period 1978–85. Local impacts, within the 17 000 km2 area most affected by emissions from Sudbury smelters, were also estimated and compared with the provincial values. The estimated numbers of acidic lakes in Ontario in which viable sportfish populations have disappeared were 119 lake trout lakes (5.1% of known lake trout lakes), 34 brook trout lakes (1.6%), 52 smallmouth bass lakes (2.2%), and 14 walleye lakes (0.3%). Most of these affected lakes were in the Sudbury zone, where fish populations, particularly those of lake trout, began declining more than 30 yr ago. The estimated numbers of critically acidic lakes in the Sudbury zone were 94 lake trout lakes, 14 brook trout lakes, 18 smallmouth bass lakes, and 7 walleye lakes. More recent sampling of a subset of Sudbury lakes indicated that substantial water quality improvements have occurred as a result of emission reductions from Sudbury smelters.
Dynamics in Year-Class Strength, Growth, and Calcified-Structure Size of Native Lake Trout (Salvelinus namaycush) Exposed to Moderate Acidification and Whole-Lake Neutralization
Authors: Casselman John M. , Gunn John M.
Published: July 2009

Accurate age-interpretation techniques were developed, using scales and otoliths, to examine the role of whole-lake neutralization in the resurgence of a lake trout (Salvelinus namaycush) fishery in Nelson Lake (pH 5.7) near Sudbury, Ontario. Calcified structures and data from 860 lake trout were collected from 1972 to 1987. The population was characterized by the regular cyclic occurrence of strong year classes, which were probably an effect of pulse angling, cyclic food abundance, and possibly intraspecific interaction. The majority (65.8%) of the lake trout caught in the exceptional winter fishery of 1980 (3.3 kg∙ha−1) were in the lake prior to liming in 1975–76. Young lake trout (up to age 4) of the 1975 and 1976 year classes grew bigger and had larger scales than other year classes from 1973 to 1977, coinciding with an increase in hypolimnetic zooplankton, probably related to improved water quality. Otoliths grew significantly larger and more translucent and exceeded relative growth of scales and body for all ages in 1976 (18% greater) and for the 1976 year class, confirming that otolith accretion can come from the ambient water because liming increased the calcium content by 33% that year, the only observed direct effect of the treatment.
Distribution of Waterfowl Broods in Sudbury Area Lakes in Relation to Fish, Macroinvertebrates, and Water Chemistry
Authors: McNicol D. K. , Wayland M.
Published: July 2009

We studied habitat selection by insectivorous waterfowl in 65 small lakes near Sudbury, Ontario. Data on environmental variables (pH, alkalinity, conductivity, calcium, total phosphorus, dissolved organic carbon (DOC), and area), fish, and littoral macroinvertebrates indicated that the distribution of broods was influenced by differences in invertebrate prey assemblages in lakes with differing degrees of acid stress and types offish predation. Lakes ranged in pH from 4.2 to 7.7 (mean = 5.8); 40% were fishless, 43% were dominated by yellow perch (Perca flavescens) or white sucker (Catostomus commersoni) (YP/WS), and the remainder contained only small cyprinids, sticklebacks, or darters (C/S). Fishless lakes were more acid than lakes with fish. Compared with fishless lakes, C/S lakes had higher levels of DOC and YP/WS lakes were larger. Macroinvertebrate composition was strongly related to fish composition and suggested increasing predation along a gradient: fishless < C/S < YP/WS. pH-related variables distinguished lakes with a taxonomically rich benthos from those with a taxonomically poorer fauna. Insectivorous waterfowl selected fishless lakes over lakes with fish and C/S over YP/WS lakes. Lakes with species-rich, acid-sensitive invertebrate assemblages were not selected over those typified by species-poor, acid-tolerant ones.
SEIZURE ABATEMENT WITH SINGLE DC PULSES: IS PHASE RESETTING AT PLAY?
Authors: OSORIO IVAN , FREI M. G.
Published: July 2009

Topological approaches for seizure abatement have received scarce attention. The ability to reset the phase of biological oscillations has been widely exploited in cardiology, as evidenced in part by the usefulness of implantable of defibrillators, but not in epileptology. The aim of this work is to investigate the feasibility of seizure blockage using single or brief monophasic (DC) pulse trains.

Single DC or brief (0.1 s) pulse trains were delivered manually or automatically to generalized seizures, induced in rats with the convulsant 3-mercaptoprionic acid, a GABA inhibitor. Treatment outcome (blocked vs. not blocked seizures) was ascertained visually and correlated with the "rhythmicity index", an indirect estimate of neuronal synchrony level.

Blockage using single or brief (0.1 s) DC pulses was consistently achieved for seizures with a rhythmicity index > 0.6, while seizures with levels <0.6 were not, although transient phase changes in their oscillations were effected.

This work reveals that level of neuronal synchronization may be an important factor in determining the probability of seizure blockage. Seizure blockage using single or brief DC pulse trains and its effects on neural tissue merit further investigation. The clinical applicability of this therapeutic modality and means to enhance it are discussed.
GENERATION OF 3D JULIA SETS FROM SWITCHING POLYNOMIAL MAPS
Authors: CHENG JIN , TAN JIANRONG , GAN CHUNBIAO
Published: July 2009

Inspired by the study of 3D fractals based on quadratic polynomial maps,1 this paper presents a novel approach for generating 3D Julia sets by utilizing a family of switching polynomial maps in order to further enrich the form of 3D fractals. Rotational symmetries in the structures of resulting Julia sets with different switching parameters are theoretically analyzed and proved. Experimental results obtained from various parameters and coefficients in the switching maps are provided and discussed in detail. It is hoped that the investigations conducted in this paper can bring on new perspectives for the generalization of 3D fractals.
CHAOTIC FEATURE OF MARTIN PROCESS IMPOSED ON THE COSINE FUNCTION
Authors: GAO CHUANHOU , ZHOU ZHIMIN , ZENG JIUSUN , CHEN JIMING
Published: July 2009

By analyzing the phase diagram of Martin process on the cosine function, it is shown that with the change of system parameters the system will eventually converge to a chaotic attractor. The process is repeated and stable focus, period doubling bifurcation occurs during this process. Further computation gives the maximum Lyapunov exponent of the system and meanwhile, the bifurcation diagram is drawn. Thus it is proved from theory that the system exhibits strong chaotic properties.
A SIMULATION METHOD FOR LOG-FRACTIONAL STABLE MOTION
Authors: MOHAMMADI MOHAMMAD , MOHAMMADPOUR ADEL
Published: July 2009

Stoev and Taqqu1 presented a fast simulation method for the linear fractional stable motion (lfsm) process, using the fast Fourier transform. In this paper, we extend this method for fast simulation of the log-fractional stable motion (log-fsm) process. These two heavy-tailed processes, i.e. lfsm and log-fsm, can be used for modeling the modern telecommunication networks. In addition, a necessary and sufficient condition is given for the efficiency of this method. Finally, an upper bound for approximation error is presented.
SECURE FRACTAL IMAGE CODING BASED ON FRACTAL PARAMETER ENCRYPTION
Authors: LIAN SHIGUO , CHEN XI , YE DENGPAN
Published: July 2009

In recent work, various fractal image coding methods are reported, which adopt the self-similarity of images to compress the size of images. However, till now, no solutions for the security of fractal encoded images have been provided. In this paper, a secure fractal image coding scheme is proposed and evaluated, which encrypts some of the fractal parameters during fractal encoding, and thus, produces the encrypted and encoded image. The encrypted image can only be recovered by the correct key. To maintain security and efficiency, only the suitable parameters are selected and encrypted through investigating the properties of various fractal parameters, including parameter space, parameter distribution and parameter sensitivity. The encryption process does not change the file format, keeps secure in perception, and costs little time or computational resources. These properties make it suitable for secure image encoding or transmission.
BORDER DETECTION OF SKIN CANCER CELLS WITH FRACTAL DIMENSION
Authors: UTHAYAKUMAR R. , JAYALALITHA G.
Published: July 2009

In this paper we study a model of skin cancer (MM) in vitro, using geometry of fractals as the method of analysis. The fractal dimensions of moles (skin cancer cells) growth pattern have been measured by using the methods of Box-counting method (DB) and Sausage method (DS). The cell growth of this cancer can be modeled by Hidden Markov model (HMM) and percolation model which are depending upon the time complexity. From these models we can find the shape of the irregularity border by using the probability distribution of the cells. The variation in the irregular border of the skin cancer has been found out using ANOVA test and cell's compactness. The fractal approach led to very promising results which improved the determination and examination of the stage of skin cancer.
SENSITIVITY ANALYSIS FOR HIDDEN VARIABLE FRACTAL INTERPOLATION FUNCTIONS AND THEIR MOMENTS
Authors: WANG HONG-YONG
Published: July 2009

The sensitivity analysis for a class of hidden variable fractal interpolation functions (HVFIFs) and their moments is made in the work. Based on a vector valued iterated function system (IFS) determined, we introduce a perturbed IFS and investigate the relations between the two HVFIFs generated by the IFS determined and its perturbed IFS, respectively. An explicit expression for the difference between the two HVFIFs is presented, from which, we show that the HVFIFs are not sensitive to a small perturbation in IFSs. Furthermore, we compute the moment integrals of the HVFIFs and discuss the error of moments of the two HVFIFs. An upper estimate for the error is obtained.
JULIA SET OF THE NEWTON TRANSFORMATION FOR SOLVING SOME COMPLEX EXPONENTIAL EQUATION
Authors: WANG XINGYUAN , YU XUEJING
Published: July 2009

We extend Kim's complex exponential function, come up with theory about the Julia set of Newton's transformation for general exponential equation, analyze the behavior of the roots of some complex exponential equation, and prove the symmetry, boundedness and embedding topology distribution structure of basins of attraction of the Julia set in theory.
EFFECTS OF DIABETES AND EXERCISE ON SOFT CONNECTIVE TISSUE PROPERTIES AT THE KNEE IN THE RAT
Authors: Fischer Kenneth J. , Novak Elizabeth A. , Smirnova Irina V. , Reddy G. Kesava , Stehno-Bittel Lisa
Published: July 2009

The primary diabetes-related health concerns are neuropathy and cardiovascular changes. Connective tissue changes can also affect quality of life by increasing ligament and joint capsule stiffness, impairing proprioception, limiting function, and leading to greater risk of falling. Our objectives were to evaluate effects of Type I diabetes and exercise on medial collateral ligament properties and overall knee-joint stiffness and stress relaxation. Thirty-four male Sprague–Dawley rats, approximately two months old, were divided into three groups—sedentary controls (n=10), sedentary diabetics (n=10) and exercised diabetics (n=14). Diabetes was induced by streptozotocin injection. Exercised rats ran 5 days/week, 1 hr/day, at 20 m/min. All animals were sacrificed seven weeks after induction of diabetes. Stiffness and stress relaxation of the whole knee joint was tested in distraction and anterior–posterior tibial displacement. The joint capsule and knee ligaments were then sectioned, preserving the medial collateral ligament (MCL). The MCL structural properties were tested by knee distraction at a flexion angle of 40°. Whole joint stiffness was 23% higher for anterior tibial displacement in the exercised diabetic group, and 31% higher for posterior tibial displacement, compared to controls. Whole joint stress relaxation in distraction was 25% lower for the exercised diabetic group. No differences were found for MCL properties. Diabetes and exercise clearly increased joint stiffness. The effects may be due to tissue adaptation, but appear more likely to be due to increased blood flow that promotes increased tissue glycation in the joint capsule.
AN IMPAIRMENT-BASED INTERVENTION FOR A PATIENT WITH NON-SPECIFIC BILATERAL HIP PAIN: CLINICAL AND BIOMECHANICAL OUTCOMES
Authors: Johanson Marie A. , Greenfield Bruce H. , Greene Brenda L. , Abelew Thomas A.
Published: July 2009

Study design: Case study. Background: To date, there is little research that has examined the association of impairments at the hip with cumulative trauma syndromes of the hip. The purposes of this case report are to: (1) describe clinical outcomes for a patient with non-specific bilateral musculoskeletal hip pain associated with recreational walking, (2) explore the relationship between this patient's impairments and her cumulative trauma syndrome at the hip, and (3) integrate biomechanical analysis with this patient's clinical diagnosis. Case description: The patient was a 28-year-old female research assistant who reported anterior bilateral hip pain during recreational walking. After examination, the physical therapist diagnosed primary impairments of hip pain, limited hip flexion range of motion (ROM), and weakness of hip musculature, resulting in her ambulation limitations. Intervention consisted of a home exercise program (HEP) designed to strengthen the iliopsoas, gluteus maximus, and gluteus medius (specifically, the posterior portion), increase extensibility of the IT Band and medial hamstrings, and promote posterior glide of the proximal femur. The patient's HEP was the only intervention she received. There were follow-up telephone conversations, but no clinical re-examination for ten weeks. The patient performed the HEP a total of 41 days over the ten week period. Biomechanical gait analysis was performed pre- and post-intervention. Outcomes: Following intervention, the patient was pain-free during recreational walking, and passive hip flexion ROM and manual muscle testing (MMT) grades of hip musculature improved. Global score on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) improved ten points. Motion analysis, force plate analysis, and electromyography (EMG) showed that maximum hip extension decreased, maximum hip flexion increased, maximum ground reaction force increased, activation of the gluteus maximus increased, while activation of the gluteus medius and tensor fascia latae (TFL) decreased following the intervention. Discussion: This patient's changes in muscle activity following a HEP appear largely consistent with improved symptoms based on theoretical descriptions of a common muscle imbalance (shortened and overactive TFL and weakness of the gluteus maximus and posterior portion of the gluteus medius), thought to contribute to increased femoral medial rotation.