bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying habitat structure: surface convolution and living space for species in complex environments
Authors: Warfe D. M. , Barmuta L. A. , Wotherspoon S.
Published: December 2008

Habitat complexity is often used to explain the distribution of species in environments, yet the ability to predict outcomes of structural differences between habitats remains elusive. This stems from the difficulty and lack of consistency in measuring and quantifying habitat structure, making comparison between different habitats and systems problematic. For any measure of habitat structure to be useful it needs to be applicable to a range of habitats and have relevance to their associated fauna. We measured three differently‐shaped macrophyte analogues with nine indices of habitat structure to determine which would best distinguish between their shape and relate to the abundance and rarefied species richness of their associated macroinvertebrate assemblages. These indices included the physical, whole‐plant attributes of surface area (SA) and plant volume (PV), the interstitial space attributes of average space size and frequency (ISI), average refuge space from predation (Sp/Pr), and total refuge space (FFV), and the degree of surface convolution at a range of scales (i.e. the fractal dimension at four spatial scales: 7.5×, 5×, 2.5× and 1× magnification). We found a high degree of inter‐correlation between the structural indices such that they could be organised into two suites: one group describing interstitial space and surface convolution at coarse scales, the other describing whole‐plant attributes and surface convolution at fine scales. Two of these indices fell into both suites: the average refuge space from predation (Sp/Pr) and the fractal dimension at 5× magnification. These two measures were also strongly related to macroinvertebrate abundance and rarefied species richness, which points to their usefulness in quantifying habitat structure and illustrates that habitat structure depends not just on shape, but on the space associated with shape.
Nested patterns of community assembly in the colonisation of artificial canopy habitats by oribatid mites
Authors: Lindo Zoë , Winchester Neville N. , Didham Raphael K.
Published: December 2008

An observed species–area relationship (SAR) in assemblages of oribatid mites inhabiting natural canopy habitats (suspended soils) led to an experimental investigation of how patch size, height in canopy and moisture influence the species richness, abundance and community composition of arboreal oribatid mites. Colonisation by oribatid mites on 90 artificial canopy habitats (ACHs) of three sizes placed at each of three heights on the trunks of ten western redcedar trees was recorded over a 1‐year period. Fifty‐nine oribatid mite species colonised the ACHs, and richness increased with the moisture content and size of the habitat patch. Oribatid mite species richness and abundance, and ACH moisture content decreased with increasing ACH height in the canopy. Patterns in the species richness and community composition of ACHs were non‐random and demonstrated a significant nested pattern. Correlations of patch size, canopy height and moisture content with community nestedness suggest that species‐specific environmental tolerances combined with the differential dispersal abilities of species contributed to the non‐random patterns of composition in these habitats. In line with the prediction that niche‐selection filters out species from the regional pool that cannot tolerate environmental harshness, moisture‐stressed ACHs in the high canopy had lower community variability than ACHs in the lower canopy. Colonising source pools to ACHs were almost exclusively naturally‐occurring canopy sources, but low levels of colonisation from the forest floor were apparent at low heights within the ACH system. We conclude that stochastic dispersal dynamics within the canopy are crucial to understanding oribatid mite community structure in suspended soils, but that the relative importance of stochastic dispersal assembly may be dependent on a strong deterministic element to the environmental tolerances of individual species which drives non‐random patterns of community assembly.
Neuronal migration disorders: clinical, neuroradiologic and genetics aspects
Authors: Spalice Alberto , Parisi Pasquale , Nicita Francesco , Pizzardi Giorgia , Del Balzo Francesca , Iannetti Paola
Published: December 2008

Disorders of neuronal migration are a heterogeneous group of disorders of nervous system development.

One of the most frequent disorders is lissencephaly, characterized by a paucity of normal gyri and sulci resulting in a ‘smooth brain’. There are two pathologic subtypes: classical and cobblestone. Six different genes could be responsible for this entity (LIS1, DCX, TUBA1A, VLDLR, ARX, RELN), although co‐delection of YWHAE gene with LIS1 could result in Miller–Dieker Syndrome.

Heterotopia is defined as a cluster of normal neurons in abnormal locations, and divided into three main groups: periventricular nodular heterotopia, subcortical heterotopia and marginal glioneural heterotopia. Genetically, heterotopia is related to Filamin A (FLNA) or ADP‐ribosylation factor guanine exchange factor 2 (ARFGEF2) genes mutations.

Polymicrogyria is described as an augmentation of small circonvolutions separated by shallow enlarged sulci; bilateral frontoparietal form is characterized by bilateral, symmetric polymicrogyria in the frontoparietal regions. Bilateral perisylvian polymicrogyria results in a clinical syndrome manifested by mild mental retardation, epilepsy and pseudobulbar palsy. Gene mutations linked to this disorder are SRPX2, PAX6, TBR2, KIAA1279, RAB3GAP1 and COL18A1.

Schizencephaly, consisting in a cleft of cerebral hemisphere connecting extra‐axial subaracnoid spaces and ventricles, is another important disorder of neuronal migration whose clinical characteristics are extremely variable. EMX2 gene could be implicated in its genesis.

Focal cortical dysplasia is characterized by three different types of altered cortical laminations, and represents one of most severe cause of epilepsy in children. TSC1 gene could play a role in its etiology.

Conclusion: This review reports the main clinical, genetical and neuroradiological aspects of these disorders. It is hoped that accumulating data of the development mechanisms underlying the expanded network formation in the brain will lead to the development of therapeutic options for neuronal migration disorders.
Intravitreal bevacizumab (Avastin®) for neovascular age‐related macular degeneration in treatment‐naive patients
Authors: Pedersen Karen Bjerg , Sjølie Anne Katrin , Møller Flemming
Published: December 2008

Purpose:  To report the effects of intravitreal bevacizumab (Avastin®) in treatment‐naive patients with exudative age‐related macular degeneration (ARMD) assessed by visual acuity (VA), optical coherence tomography (OCT) and contrast sensitivity.

Methods:  A prospective, uncontrolled, pilot study of 26 eyes of 26 patients, all previously treatment‐naive to photodynamic therapy, argon laser or anti‐vascular endothelial growth factor (VEGF), were treated with one or more intravitreal injections of 1.25 mg bevacizumab. Of the 26 patients, 15 (57.7%) had occult choroidal neovascularization (CNV), 6 (23.1%) had predominantly classic CNV and 5 (19.2%) had minimally classic CNV. Ophthalmic outcome measures included changes in standardized Early Treatment Diabetic Research Study (ETDRS) VA, contrast sensitivity and OCT. The patients were examined at baseline and 1 week, 6 weeks, 3 months and 6 months after the first injection. Re‐treatment was given on an ‘as needed’ basis.

Results:  Twenty‐four eyes of 24 patients completed 6 months of follow‐up. Two patients chose to discontinue the study. Mean ETDRS VA score improved from 55 letters at baseline to 60 letters at 1 week (P < 0.01) and to 61 letters at 6 weeks (P < 0.01). No significant improvement in VA from baseline was found after 3 and 6 months. Patients with pigment epithelial detachment (PED) had a significantly worse outcome in VA at 6 months. Contrast sensitivity improved from baseline to 3 or 6 months, but this improvement was not statistically significant. Mean macular thickness decreased significantly from baseline to all follow‐up examinations (P < 0.01).

Conclusion:  Mean ETDRS VA improved significantly after 1 and 6 weeks; thereafter, it remained stable throughout the study period. Macular thickness improved significantly at all time points. The results indicate that 1.25 mg intravitreal bevacizumab is associated with functional as well as morphological improvement among treatment‐naive ARMD patients.
Assessment by Finite Element Modeling Indicates That Surgical Intramuscular Aponeurotomy Performed Closer to the Tendon Enhances Intended Acute Effects in Extramuscularly Connected Muscle
Authors: Yucesoy Can A. , Huijing Peter A.
Published: December 2008

The effects of location of aponeurotomy on the muscular mechanics of extramuscularly connected muscle were assessed. Using finite element modeling, extensor digitorum longus muscle of the rat was studied for the effects of aponeurotomy performed in each of three locations on the proximal aponeurosis: (1) a proximal location (case P), (2) an intermediate location (case I), and (3) a distal location (case D). Proximo-distal force differences were more pronounced for more proximal aponeurotomy. The location also affected proximally and distally assessed muscle length-force characteristics: (1) Muscle optimum length and active slack length shifted differentially to higher lengths, increasing slack to optimum length range (for D to P: distally by 15–44%; proximally by 2–6%). (2) Muscle forces decreased at all lengths (e.g., for D to P distal optimal force=88–68% and proximal optimal force=87–60% of intact values, respectively). Increased length range and force decreases were highest for case P, as were effects on muscle geometry: gap length within the proximal aponeurosis; decreased proximal fiber population pennation angle. Parallel, but not serial, heterogeneity of sarcomere length was highest in case P: (a) For the distal fiber population, sarcomere shortening was highest; (b) for the proximal population, sarcomeres were longer. It is concluded that if aponeurotomy is performed closer to the tendon, intended surgical effects are more pronounced. For bi-articular muscle, mechanics of both proximal and distal joints will be affected, which should be considered in selecting the location of aponeurotomy for optimal results at both joints.
Defining the Flexion-Extension Axis of the Ulna: Implications for Intra-Operative Elbow Alignment
Authors: Brownhill James R. , Ferreira Louis M. , Pichora James E. , Johnson James A. , King Graham J. W.
Published: December 2008

The increased utilization of total elbow replacements has resulted in a correspondingly increased number of failed implants requiring revision. The most common reason for revision is aseptic loosening of the ulnar component due to polyethylene induced osteolysis. Implant malalignment is thought to be an important cause of bearing wear and implant failure. The ulnar flexion axis can be used to accurately align the ulnar component of the elbow implant; however, the optimal method of determining this axis intra-operatively is unknown. This in vitro study determined the relationship amongst kinematically and anatomically defined ulnar flexion axes in an effort to improve the accuracy of ulnar component positioning. Five different techniques were used to determine the ulnar flexion axis in 12 cadaveric specimens, 3 kinematic and 2 anatomic. The techniques were compared with the screw displacement axis from simulated elbow flexion. An anatomic measurement technique using the guiding ridge of the greater sigmoid notch of the ulna and the radial head was found to most accurately replicate the position and orientation of the screw displacement axis of the elbow (p<0.05). Because an anatomically derived flexion axis can be determined using both pre-operative imaging techniques, as well as with intra-operative guides, it is more practical than kinematically derived techniques requiring tracking systems for clinical application and should provide reliable and consistent results.
Cytoskeleton-Membrane Interactions in Neuronal Growth Cones: A Finite Analysis Study
Authors: Allen Kathleen B. , Sasoglu F. Mert , Layton Bradley E.
Published: December 2008

Revealing the molecular events of neuronal growth is critical to obtaining a deeper understanding of nervous system development, neural injury response, and neural tissue engineering. Central to this is the need to understand the mechanical interactions between the cytoskeleton and the cell membrane, and how these interactions affect the overall growth mechanics of neurons. Using finite element analysis, the stress in the membrane produced by an actin filament or a microtubule acting against a deformable membrane was modeled, and the deformation, stress, and strain were computed for the membrane. Parameters to represent the flexural rigidities of the well-studied actin and tubulin cytoskeletal proteins, as well as the mechanical properties of cell membranes, were used in the simulations. Our model predicts that a single actin filament is able to produce a normal contact stress on the cell membrane that is sufficient to cause membrane deformation but not growth. Our model also predicts that under clamped boundary conditions a filament with a buckling strength equal to or smaller than an actin filament would not cause the areal strain in the membrane to exceed 3%, and therefore the filament is incapable of causing membrane rupture or puncture to a safety factor of ∼15–25. Decreasing the radius of the membrane upon which the normal contact stress is acting allows an increase in the amount of normal contact stress that the membrane can withstand before rupture. The model predicts that a 50nm radius membrane can withstand ∼4MPa of normal contact stress before membrane rupture whereas a 250nm radius membrane can withstand ∼2.5MPa. Understanding how the mechanical properties of cytoskeletal elements have coevolved with their respective cell membranes may yield insights into the events that gave rise to the sequences and superquaternary structures of the major cytoskeletal proteins. Additionally, numerical modeling of membranes can be used to analyze the forces and stresses generated by nanoscale biological probes during cellular injection.
Label-Free Biomedical Imaging with High Sensitivity by Stimulated Raman Scattering Microscopy
Authors: Freudiger Christian W. , Min Wei , Saar Brian G. , Lu Sijia , Holtom Gary R. , He Chengwei , Tsai Jason C. , Kang Jing X. , Xie X. Sunney
Published: December 2008

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing high-frequency (megahertz) phase-sensitive detection. SRS microscopy has a major advantage over previous coherent Raman techniques in that it offers background-free and readily interpretable chemical contrast. We show a variety of biomedical applications, such as differentiating distributions of omega-3 fatty acids and saturated lipids in living cells, imaging of brain and skin tissues based on intrinsic lipid contrast, and monitoring drug delivery through the epidermis.
Hejira in a Jetta
Authors: Parrish Mary
Published: December 2008

Spiral Jetta
. A Road Trip Through the Land Art of the American West.
By Erin Hogan
. University of Chicago Press, Chicago, 2008. 188 pp. $20. ISBN 9780226348452.

Horgan's often humorous narrative of her journey to several monumental earthworks from the 1970s and 1980s interweaves her personal observations and responses with art history and theory.
Concordant Proficiency in Measurement of T-Cell Immunity in Human Immunodeficiency Virus Vaccine Clinical Trials by Peripheral Blood Mononuclear Cell and Enzyme-Linked Immunospot Assays in Laboratories from Three Continents
Authors: Boaz Mark J. , Hayes Peter , Tarragona Tony , Seamons Laura , Cooper Andrew , Birungi Josephine , Kitandwe Paul , Semaganda Aloysius , Kaleebu Pontiano , Stevens Gwynneth , Anzala Omu , Farah Bashir , Ogola Simon , Indangasi Jackton , Mhlanga Patrick , Van Eeden Melanie , Thakar Madhuri , Pujari Ashwini , Mishra Shadri , Goonetilleke Nilu , Moore Stephen , Mahmoud Abdul , Sathyamoorthy Pattabiraman , Mahalingam Jayashri , Narayanan Paranji R. , Ramanathan Vadakkuppattu D. , Cox Josephine H. , Dally Len , Gill Dilbinder K. , Gilmour Jill
Published: December 2008

The gamma interferon (IFN-γ) enzyme-linked immunospot (ELISPOT) assay is used routinely to evaluate the potency of human immunodeficiency virus (HIV) vaccine candidates and other vaccine candidates. In order to compare candidates and pool data from multiple trial laboratories, validated standardized methods must be applied across laboratories. Proficiency panels are a key part of a comprehensive quality assurance program to monitor inter- and intralaboratory performance, as well as assay performance, over time. Seven International AIDS Vaccine Initiative-sponsored trial sites participated in the proficiency panels described in this study. At each laboratory, two operators independently processed identical sample sets consisting of frozen peripheral blood mononuclear cell (PBMC) samples from different donors by using four blind stimuli. PBMC recovery and viability after overnight resting and the IFN-γ ELISPOT assay performance were assessed. All sites demonstrated good performance in PBMC thawing and resting, with a median recovery of 78% and median viability of 95%. The laboratories were able to detect similar antigen-specific T-cell responses, ranging from 50 to >3,000 spot-forming cells per million PBMC. An approximate range of a half log in results from operators within or across sites was seen in comparisons of antigen-specific responses. Consistently low background responses were seen in all laboratories. The results of these proficiency panels demonstrate the ability of seven laboratories, located across three continents, to process PBMC samples and to rank volunteers with differential magnitudes of IFN-γ ELISPOT responses. These findings also illustrate the ability to standardize the IFN-γ ELISPOT assay across multiple laboratories when common training methods, reagents such as fetal calf serum, and standard operating procedures are adopted. These results are encouraging for laboratories that are using cell-based immunology assays to test HIV vaccines and other vaccines.
Protection against AsiaticTaenia soliumInduced by a Recombinant 45W-4B Protein
Authors: Luo Xuenong , Zheng Yadong , Hou Junling , Zhang Shaohua , Cai Xuepeng
Published: December 2008

Taenia soliumis a great threat not only to human health but also to the pig-raising industry. Oncospheral stage-specific 45W proteins are good candidates for the development of anticysticercosis vaccines. In this study, a recombinant 45W-4B protein was highly produced and used for vaccination. Two animal trials resulted in a significant reduction in parasite burden induced by the definite protein against AsiaticT. solium, up to 97.0% and 98.4%, respectively. These provide informative results for the development of effective 45W-4B vaccines against cysticercosis caused by both Chinese and MexicanT. soliumisolates and even by other isolates.
Fourteen Years of Severe Arthralgia in a Man without Gastrointestinal Symptoms: Atypical Whipple's Disease
Authors: Mancini Fabiola , Sbaragli Serena , Colivicchi Gilberto , Cassone Antonio , Ciervo Alessandra
Published: December 2008

We report here the case of Whipple's disease in a 60-year-old man with severe arthralgia and systemic disorders but without gastrointestinal manifestations. The patient had different clinical diagnoses over a period of 14 years. We identified
Tropheryma whipplei
by real-time PCR. Molecular typing was also performed by sequencing the 16S-23S rRNA intergenic spacer region and domain III of the 23S rRNA gene.
Association of High
Orientia tsutsugamushi
DNA Loads with Disease of Greater Severity in Adults with Scrub Typhus
Authors: Sonthayanon Piengchan , Chierakul Wirongrong , Wuthiekanun Vanaporn , Phimda Kriangsak , Pukrittayakamee Sasithon , Day Nicholas P. , Peacock Sharon J.
Published: December 2008

Orientia tsutsugamushi
, the cause of scrub typhus, is a major pathogen in the Asia-Pacific region. The severity of infection ranges from mild features to multiorgan failure and death. The aim of this prospective study was to define the
O. tsutsugamushi
loads in the blood samples of patients with scrub typhus on the day of hospital admission and to determine whether this was associated with disease severity. Quantitation was performed using a real-time PCR assay targeting the 16S rRNA gene of
O. tsutsugamushi
. A total of 155 patients with a confirmed diagnosis of scrub typhus had a median (interquartile range [IQR], range)
O. tsutsugamushi
DNA load in blood of 13 (0 to 334, 0 to 310,253) copies/ml. This included 74 patients who had undetectable bacterial loads. An analysis of bacterial load versus clinical features for all 155 patents demonstrated that duration of illness (
P
< 0.001), presence of eschar (
P
= 0.004), and concentrations of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase (
P
< 0.001 for all three) were positively correlated with bacterial load. Patients who died had a significantly higher bacterial load than those who survived (mean [standard deviation] values: 17,154 [12.7] versus 281 [5.2] copies/ml;
P
< 0.001). This study has demonstrated a relationship between bacterial load and disease severity in adults with scrub typhus.
Mutational Analysis of a Conserved Glutamic Acid Required for Self-Catalyzed Cross-Linking of Bacteriophage HK97 Capsids
Authors: Dierkes Lindsay E. , Peebles Craig L. , Firek Brian A. , Hendrix Roger W. , Duda Robert L.
Published: December 2008

The capsid of bacteriophage HK97 is stabilized by ∼400 covalent cross-links between subunits which form without any action by external enzymes or cofactors. Cross-linking only occurs in fully assembled particles after large-scale structural changes bring together side chains from three subunits at each cross-linking site. Isopeptide cross-links form between asparagine and lysine side chains on two subunits. The carboxylate of glutamic acid 363 (E363) from a third subunit is found ∼2.4 Å from the isopeptide bond in the partly hydrophobic pocket that contains the cross-link. It was previously reported without supporting data that changing E363 to alanine abolishes cross-linking, suggesting that E363 plays a role in cross-linking. This alanine mutant and six additional substitutions for E363 were fully characterized and the proheads produced by the mutants were tested for their ability to cross-link under a variety of conditions. Aspartic acid and histidine substitutions supported cross-linking to a significant extent, while alanine, asparagine, glutamine, and tyrosine did not, suggesting that residue 363 acts as a proton acceptor during cross-linking. These results support a chemical mechanism, not yet fully tested, that incorporates this suggestion, as well as features of the structure at the cross-link site. The chemically identical isopeptide bonds recently documented in bacterial pili have a strikingly similar chemical geometry at their cross-linking sites, suggesting a common chemical mechanism with the phage protein, but the completely different structures and folds of the two proteins argues that the phage capsid and bacterial pilus proteins have achieved shared cross-linking chemistry by convergent evolution.
Severe Acute Respiratory Syndrome Coronavirus Protein 6 Is Required for Optimal Replication
Authors: Zhao Jincun , Falcón Ana , Zhou Haixia , Netland Jason , Enjuanes Luis , Pérez Breña Pilar , Perlman Stanley
Published: December 2008

Severe acute respiratory syndrome coronavirus (SARS-CoV) encodes several accessory proteins of unknown function. One of these proteins, protein 6 (p6), which is encoded by ORF6, enhances virus replication when introduced into a heterologous murine coronavirus (mouse hepatitis virus [MHV]) but is not essential for optimal SARS-CoV replication after infection at a relatively high multiplicity of infection (MOI). Here, we reconcile these apparently conflicting results by showing that p6 enhances SARS-CoV replication to nearly the same extent as when expressed in the context of MHV if cells are infected at a low MOI and accelerates disease in mice transgenic for the human SARS-CoV receptor.
Systematic review and meta-analysis of mortality in crop protection product manufacturing workers
Authors: Jones D R , Sutton A J , Abrams K R , Fenty J , Warren F , Rushton L
Published: December 2008

Objectives:

The potential health effects of the manufacture and use of crop protection chemicals were investigated through systematic review and meta-analysis of studies of cohorts of workers in the crop protection product manufacturing industry.

Methods:

Several computerised literature databases were searched from inception until December 2003, with references listed in identified articles checked for further relevant articles. Random effects meta-analyses of log standardised mortality ratios (SMRs) were carried out. Heterogeneity was explored through subgroup analyses and meta-regression; sensitivity analyses of different approaches for zero events were performed.

Results:

21 references reporting information on 37 separate cohorts for mortality were identified. The meta-SMR for all cause mortality was 0.94 (95% CI 0.88 to 1.00) (37 cohorts). Significantly raised mortality was found for cancers of the buccal cavity and pharynx, oesophagus, rectum, larynx, lung, and lymphatic and haematopoietic system with little heterogeneity being observed. Excluding studies with zero events identified additional excesses.

Conclusions:

Evidence of multiple excesses, particularly in subgroups exposed to phenoxy herbicides contaminated with dioxins, substantiates previous findings. The importance of careful treatment of zero cases was highlighted. Future systematic reviews and meta-analyses would benefit from availability of results for a standard list of causes of disease.
Taphonomy and ontogeny of a multibranched Ediacaran fossil: Bradgatia from the Avalon Peninsula of Newfoundland
Authors: Flude Lija I. , Narbonne Guy M.
Published: December 2008

Rangeomorphs, an extinct group of Ediacaran organisms with a fractal architecture and modular construction, occur abundantly in the Mistaken Point assemblage (575–560 Ma) of the Avalon Peninsula of Newfoundland. Bradgatia is represented by hundreds of specimens, collectively permitting analysis of its morphology, growth mode, and life habits. Bradgatia is a petalage that consists of a radial array of up to eight petals, each exhibiting up to four visible orders of rangeomorph branching. The taphonomy and ontogeny of Bradgatia are tightly linked by a change in preserved morphology, from juvenile I- to V-shaped specimens to larger U-shaped specimens, to the largest and ontogenetically oldest O-shaped specimens. Bradgatia probably maintained a constant number of petals that gradually spread out with age. The number of frondlets per petal does not correlate with length, suggesting either fractal or inflationary growth. Presence of a structure from which petals branch, abundance of contour-parallel specimens, differential preservation within specimens, and specimens overlying spindles and discs all imply that Bradgatia had an attached, epifaunal, suspension-feeding lifestyle. Bradgatia's multiple thin petals would have helped to filter water more efficiently, while its lack of a stem would have allowed for suspension feeding along the entire length of each petal.
A middle Cenomanian euselachian assemblage from the Dunvegan Formation of northwestern Alberta
Authors: Cook Todd D. , Wilson Mark V.H. , Murray Alison M.
Published: December 2008

A euselachian assemblage was recovered from the middle Cenomanian Dunvegan Formation situated in northwestern Alberta. This assemblage is the most northern described within the Western Interior Seaway and provides an important insight into the euselachian faunal diversity of this little-known region of the seaway. Despite its high paleolatitude, the assemblage contains a number of elasmobranch taxa, including Hybodus , Squalicorax , Archaeolamna , Cretodus , Dallasiella , and Cretoxyrhina . The Dunvegan assemblage also contains the first known reports from Canada of the odontaspid shark Johnlongia parvidens , the cretoxyrhinid shark Protolamna carteri , and the ray Pseudohypolophus mcnultyi . This assemblage extends the northern geographical range of all taxa. Preliminary comparisons with other middle Cenomanian Western Interior Seaway assemblages show that the core composition of the Dunvegan assemblage is remarkably similar to that of other time-equivalent assemblages; however, conspicuously absent are species that are exceedingly common in other localities situated farther south. We suggest that absence of these taxa from the Dunvegan localities may be caused by a temperature intolerance associated with latitude and sea-water circulation patterns, or by an inability to inhabit environments that exhibit salinity variation.
Heterogeneity in enterohemorrhagicEscherichia coliO157:H7 fecal shedding in cattle is related toEscherichia coliO157:H7 colonization of the small and large intestine
Authors: Baines Danica , Lee Byron , McAllister Tim
Published: December 2008

In the last decade, Escherichia coli O157:H7 have emerged as important pathogens of the gastrointestinal tract of humans. Healthy cattle have been identified as the primary reservoir, however, the factors affecting heterogeneous E. coli O157:H7 fecal shedding are not fully understood. The aim of this study was to investigate the contribution of E. coli O157:H7 colonization of small and large intestinal sites to the heterogeneity of fecal shedding in cattle. There was a dose-dependant E. coli O157:H7 E318N colonization of duodenum, jejunum, ileum, cecum, ascending colon, spiral colon, descending colon, and the rectoanal junction in vitro with no difference in E. coli O157:H7 colonization of the rectoanal junction and other intestinal sites. There were 10–100 times greater E. coli O157:H7 colonization of intestinal sites from persistent shedding cattle compared with nonpersistent shedding cattle. Novel pathologies were associated with E. coli O157:H7 colonization sites in the small and large intestine. The first pathology, focal petechiae, was present throughout the intestinal tract of cattle that ceased shedding E. coli O157:H7 for 5–12 weeks or in the jejunum, ileum, cecum, and ascending colon of cattle shedding E. coli O157:H7 for 4–5 months. The second pathology, mucosal hemorrhages, was present in the same sites as the focal petechiae in cattle shedding for 5 months and these hemorrhages were in the final stages of repair. Several features of these hemorrhages support this conclusion including the brown appearance, low amount of classic E. coli O157:H7 induced A/E lesions, flattened epithelium, and blunted villi. Although mucosal hemorrhages were present in the jejunum, ileum, cecum, and ascending colon in cattle shedding for 4 months, many other pathologies were also present that were indicative of hemorrhagic enteritis as evidenced by the blood red appearance of hemorrhages, severe edema, and dark red erythema. Escherichia coli O157:H7 were associated with both pathologies suggesting it is the causative agent. The current study supports a relationship between the amount of E. coli O157:H7 colonization in intestinal sites and heterogeneous fecal shedding by cattle.
Drainage and agriculture impacts on fire frequency in a southern Illinois forested bottomland
Authors: Nelson John L. , Ruffner Charles M. , Groninger John W. , Souter Ray A.
Published: December 2008

Postsettlement (1909–2003) fire history of a forested bottomland in the Mississippi Embayment of southern Illinois, USA, was determined using fire-scar analysis. The study area is a forested bottomland hardwood site, with remnant pockets of the dominant presettlement bald cypress – tupelo (Taxodium–Nyssa) vegetation. Ditch drainage was installed in 1919, with agricultural clearing and abandonment varying throughout the early and mid-twentieth century. Commercial agricultural activities ceased after the site became part of a conservation area ca. 1950. The hydrology of the site was further modified in 1957 when it was inundated for waterfowl management. Both drainage and land clearing for agriculture were associated with increased fire frequency. Although drainage was a necessary precursor to agriculture across much of this landscape, land improvement played the stronger role in determining fire frequency. The mean fire interval for the study period (1895–1965) was 1.73 years, with a minimum of 1 year and a maximum of 15 years. This frequency contrasts with the complete fire exclusion that has prevailed in the area since 1965. These results have important implications for the maintenance and restoration of forested wetland ecosystems where the present fire regime differs dramatically from that under which the now-dominant forest vegetation developed.
Do volatile organic compound emissions of Tunisian cork oak populations originating from contrasting climatic conditions differ in their responses to summer drought?
Authors: Staudt Michael , Ennajah Amel , Mouillot Florent , Joffre Richard
Published: December 2008

The intrinsic variability of volatile organic compound emissions and photosynthetic parameters in response to two drying cycles was investigated on Quercus suber L. saplings originating from three Tunisian populations native to contrasting climates. Emissions mainly included monoterpenes plus traces of sesquiterpenes and methylsalicylate that steadily decreased during the experiment unrelated to treatments. Instead, monoterpene emissions increased by 30% during a first moderate drought and remained enhanced after rewatering, while CO2–H2O gas exchange was reduced by 30%. A second severe drought decreased monoterpene emissions to about two third of controls, strongly inhibited gas exchange and photochemical efficiency, and caused a partial loss of chlorophyll. Rewatering led to only partial recovery of emissions and photosynthetic parameters of stressed plants whose biomasses and leaf nitrogen and chlorophyll contents were lower than in control plants. There was no clear difference among populations in volatile organic compound emissions or photosynthetic parameters. However, the population inhabiting the most arid region had intrinsically smaller leaves with lower specific leaf masses and higher drought-related leaf losses than populations native to less arid climates. These results indicate an adaptive shift from stress-tolerating towards stress-avoiding ecotypes under arid climates involving mainly morphological adaptations without apparent differentiation in volatile organic compound production, probably because of its high phenological plasticity.
The importance of being the first pollen in the strobili of Scots pine
Authors: Varis Saila , Santanen Arja , Pakkanen Anne , Pulkkinen Pertti
Published: December 2008

Timing of pollen arrival may affect the level of seeds fertilized by pollen from outside seed orchards, especially in seed orchards of Scots pine ( Pinus sylvestris L.) established in southern Finland with stock from northern populations. We performed sequential pollination experiments with Scots pine pollen collected from seed orchard clones originating from southern and northern Finland and recipient strobili in clones originating from southern Finland. When southern pollen was introduced first, seeds were sired equally by northern and southern genotypes. When northern pollen was introduced first, northern genotypes were found in 75% of the resulting seeds. When both pollen types were introduced at the same time, the resulting seed crop was split almost equally between northern and southern genotypes. These results do not unconditionally support the idea that the first pollen grain in the pollen chamber always fertilizes the ovum; instead, they suggest a more complex way of competition between pollen grains.
TELEPARALLEL ENERGY–MOMENTUM DISTRIBUTION OF STATIC AXIALLY SYMMETRIC SPACETIMES
Authors: SHARIF M. , AMIR M. JAMIL
Published: December 2008

This paper is devoted to discuss the energy–momentum for static axially symmetric spacetimes in the framework of teleparallel theory of gravity. For this purpose, we use the teleparallel versions of Einstein, Landau–Lifshitz, Bergmann and Möller prescriptions. A comparison of the results shows that the energy density is different but the momentum turns out to be constant in each prescription. This is exactly similar to the results available in literature using the framework of general relativity. It is mentioned here that Möller energy–momentum distribution is independent of the coupling constant λ. Finally, we calculate energy–momentum distribution for the Curzon metric, a special case of the above-mentioned spacetime.
EMPTINESS PROBABILITIES IN RANDOM SEQUENTIAL ADSORPTION ON THE BETHE LATTICE
Authors: SUDBURY AIDAN
Published: December 2008

When gas molecules bind to a surface they may do so in such a way that the adsorption of one molecule inhibits the arrival of others. Two models which have frequently been studied are the "dimer model" and the "blocking model", and rather complete solutions for these are known on the Bethe lattice. In this letter, the probability that a connected set of sites remains unoccupied is calculated.
ON POLYNOMIAL TORUS KNOTS
Authors: KOSELEFF P.-V. , PECKER D.
Published: December 2008

We show that no torus knot of type (2, n), n > 3 odd, can be obtained from a polynomial embedding t ↦ (f(t), g(t), h(t)) where (deg(f), deg(g)) ≤ (3, n + 1). Eventually, we give explicit examples with minimal lexicographic degree.
Cytosolic phospholipase A2-α is an early apoptotic activator in PEDF-induced endothelial cell apoptosis
Authors: Ho Tsung-Chuan , Chen Show-Li , Yang Yuh-Cheng , Lo Tzu-Hsiu , Hsieh Jui-Wen , Cheng Huey-Chuan , Tsao Yeou-Ping
Published: December 2008

Pigment epithelium-derived factor (PEDF) is an intrinsic antiangiogenic factor and a potential therapeutic agent. Previously, we discovered the mechanism of PEDF-induced apoptosis of human umbilical vein endothelial cells (HUVECs) as sequential induction/activation of p38 mitogen-activated protein kinase (MAPK), peroxisome proliferator-activated receptor gamma (PPAR-γ), and p53. In the present study, we investigated the signaling role of cytosolic calcium-dependent phospholipase A2-α (cPLA2-α) to bridge p38 MAPK and PPAR-γ activation. PEDF induced cPLA2-α activation in HUVECs and in endothelial cells in chemical burn-induced vessels on mouse cornea. The cPLA2-α activation is evident from the phosphorylation and nuclear translocation of cPLA2-α as well as arachidonic acid release and the cleavage of PED6, a synthetic PLA2 substrate. Such activation can be abolished by p38 MAPK inhibitor. The PEDF-induced PPAR-γ activation, p53 expression, caspase-3 activity, and apoptosis can be abolished by both cPLA2 inhibitor and small interfering RNA targeting cPLA2-α. Our observation not only establishes the signaling role of cPLA2-α but also for the first time demonstrates the sequential activation of p38 MAPK, cPLA2-α, PPAR-γ, and p53 as the mechanism of PEDF-induced endothelial cell apoptosis.
Direct upregulation of parathyroid calcium-sensing receptor and vitamin D receptor by calcimimetics in uremic rats
Authors: Mendoza Francisco J. , Lopez Ignacio , Canalejo Rocio , Almaden Yolanda , Martin David , Aguilera-Tejero Escolastico , Rodriguez Mariano
Published: December 2008

To investigate whether the effect of the calcimimetic AMG 641 and calcitriol on CaSR and VDR expression could be separated from their ability to reduce parathyroid cell proliferation, five-sixth nephrectomized (5/6 Nx) rats received vehicle, AMG 641, calcitriol, or AMG 641+calcitriol either daily for 13 days (long-term protocol) or in a single dose (short-term protocol). In the long-term protocol, AMG 641, calcitriol, and their combination significantly reduced the percentage of proliferating parathyroid cells. Proliferation was uncontrolled in the short-term protocol. A significant increase in CaSR mRNA (% vs. β-actin) was detected in rats treated with both calcitriol (1.60 ± 0.30) and AMG 641 (1.66 ± 0.25) for 13 days ( P = 0.01 vs. 5/6 Nx+vehicle, 0.89 ± 0.09); and there was a further increase when both drugs were administered simultaneously (2.46 ± 0.33). In the short-term protocol, only rats receiving AMG 641 alone (2.01 ± 0.33, P < 0.001) showed increased expression of CaSR mRNA, whereas the combination (1.81 ± 0.20) produced no additional benefit. AMG 641 also increased CaSR mRNA expression in vitro. Changes in VDR mRNA paralleled those of CaSR mRNA. In the long-term treatment, both AMG 641 (0.87 ± 0.14) and calcitriol (0.99 ± 0.12) increased VDR mRNA ( P < 0.05 vs. 5/6 Nx+vehicle, 0.49 ± 0.10), and the increase was more accentuated when the drugs were combined (1.49 ± 0.45). In the short-term protocol, only treatment with AMG 641, alone (1.52 ± 0.41) or combined with calcitriol (1.86 ± 0.24), increased VDR mRNA. In conclusion, our results demonstrate an acute increase in CaSR mRNA and VDR mRNA in the parathyroid glands of uremic rats treated with AMG 641, in which cell proliferation was uncontrolled, thus supporting a direct effect of calcimimetics on CaSR and VDR expression by hyperplastic parathyroid cells.
Stress responses and baroreflex function in coronary disease
Authors: Deley Gaelle , Lipman Ruth D. , Kannam Joseph P. , Bartolini Claudia , Taylor J. Andrew
Published: December 2008

Exaggerated pressor responses to mental stress in patients with coronary artery disease (CAD) are associated with increased risk for subsequent cardiovascular events. The integrated baroreflex gain and its mechanical and neural component were estimated and then related to the blood pressure and heart rate responses to simulated real-life stressors: mental arithmetic and public speaking. Eighteen healthy individuals (aged 61 ± 8 yr) and 29 individuals with documented CAD but no other comorbidities (aged 59 ± 8 yr) were studied. Heart rate and blood pressures were continuously assessed before, during preparation for, and during performance of a math task and a speech task. The assessment of beat-to-beat carotid diameters during baroreflex engagement was used to estimate the integrated baroreflex gain and its mechanical and neural component. The CAD subjects demonstrated significantly greater increases in heart rate and blood pressures for the performance of the speech task. However, there were no group differences in integrated cardiovagal baroreflex gain or either mechanical or neural baroreflex component. These findings indicate that the augmented pressor responses in CAD do not result from a generalized arterial baroreflex deficit.
Role of Inhibitory Neurotransmission in the Control of Canine Hypoglossal Motoneuron Activity In Vivo
Authors: Sanchez Antonio , Mustapic Sanda , Zuperku Edward J. , Stucke Astrid G. , Hopp Francis A. , Stuth Eckehard A. E.
Published: December 2008

Hypoglossal motoneurons (HMNs) innervate all tongue muscles and are vital for maintenance of upper airway patency during inspiration. The relative contributions of the various synaptic inputs to the spontaneous discharge of HMNs in vivo are incompletely understood, especially at the cellular level. The purpose of this study was to determine the role of endogenously activated GABAAand glycine receptors in the control of the inspiratory HMN (IHMN) activity in a decerebrate dog model. Multibarrel micropipettes were used to record extracellular unit activity of individual IHMNs during local antagonism of GABAAreceptors with bicuculline and picrotoxin or glycine receptors with strychnine. Only bicuculline had a significant effect on peak and average discharge frequency and on the slope of the augmenting neuronal discharge pattern. These parameters were increased by 30 ± 7% ( P < 0.001), 30 ± 8% ( P < 0.001), and 25 ± 7% ( P < 0.001), respectively. The effects of picrotoxin and strychnine on the spontaneous neuronal discharge and its pattern were negligible. Our data suggest that bicuculline-sensitive GABAergic, but not picrotoxin-sensitive GABAergic or glycinergic, inhibitory mechanisms actively attenuate the activity of IHMNs in vagotomized decerebrate dogs during hyperoxic hypercapnia. The pattern of GABAergic attenuation of IHMN discharge is characteristic of gain modulation similar to that in respiratory bulbospinal premotor neurons, but the degree of attenuation (∼25%) is less than that seen in bulbospinal premotor neurons (∼60%). The current studies only assess effects on active neuron discharge and do not resolve whether the lack of effect of picrotoxin and strychnine on IHMNs also extends to the inactive expiratory phase.
Abolishment of Serotonergic Neurotransmission to Cardiac Vagal Neurons During and After Hypoxia and Hypercapnia With Prenatal Nicotine Exposure
Authors: Kamendi H. W. , Cheng Q. , Dergacheva O. , Gorini C. , Jameson H. S. , Wang X. , McIntosh J. M. , Mendelowitz D.
Published: December 2008

Cardioinhibitory cardiac vagal neurons (CVNs) do not receive inspiratory-related excitatory inputs under normal conditions. However, excitatory purinergic and serotonergic pathways are recruited during inspiratory activity after episodes of hypoxia and hypercapnia (H/H). Prenatal nicotine (PNN) exposure is known to dramatically change cardiorespiratory responses and decrease the ability to resuscitate from H/H. This study tested whether PNN exposure alters excitatory neurotransmission to CVNs in the nucleus ambiguus during and after H/H. Spontaneous and inspiratory evoked excitatory postsynaptic currents were recorded in CVNs from rats that were exposed to nicotine (6 mg·kg−1·d−1) throughout the prenatal period. In contrast to unexposed animals, in PNN animals H/H recruited excitatory neurotransmission to CVNs during inspiratory-related activity that was blocked by the α3β4 nicotinic acetylcholine receptor (nAChR) blocker α-conotoxin AuIB (α-CTX AuIB, 100 μM) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 50 μM) and d(−)-2-amino-5-phosphonopentanoic acid (AP5, 50 μM), selective AMPA/kainate and N-methyl-d-aspartate receptor blockers, respectively. Following H/H, there was a significant increase in inspiratory-related excitatory postsynaptic currents that were unaltered by α-CTX AuIB or ondansetron, a 5-HT3 receptor blocker, but were subsequently inhibited by pyridoxalphosphate-6-azophenyl-2′, 4′-disulphonic acid (100 μM), a purinergic receptor blocker and CNQX and AP5. The results from this study demonstrate that with PNN exposure, an excitatory neurotransmission to CVNs is recruited during H/H that is glutamatergic and dependent on activation of α3β4-containing nAChRs. Furthermore, exposure to PNN abolishes a serotonergic long-lasting inspiratory-related excitation of CVNs that is replaced by recruitment of a glutamatergic pathway to CVNs post H/H.