bluuebunny/crossref_metadata_2025 huggingface dataset:
Drying Behavior of a Slip Cast Body Using a Microwave Heating
Authors: Shirai Takashi , Yasuoka Masaki , Hotta Yuji , Kinemuchi Yoshiaki , Watari Koji
Published: April 2008

To reduce the drying period a significant enhancement of manufacturing speed and improvement of productivity of ceramic fabrication were needed. The evaporation and transport of water were the keys to drying and controlling the kinetics of drying, which subsequently affects the properties of green bodies. This research was conducted to investigate the effects of rapid drying of ZnO slip cast bodies by microwave drying and compared with those dried by conventional drying techniques. From these results, the extent of warpage of a dried body was smaller in microwave drying than in other conventional drying methods. Furthermore, the number and size of pores were smaller for this drying technique than for other drying methods after sintering. Microwave heating was tentatively considered as a small difference in the water content between the inside and the outside of the green body, because the free and bound waters with NH4+ salt of polyacrylic acid in a green body were selectively heated compared with ZnO powder, and evaporation and diffusion of water was done efficiently from the inside of the green body under microwave drying. Microwave drying has merits in terms of both the rapid drying and structural uniformity of dried bodies. It not only reduces drying period, but also improves the characteristics of green and sintered bodies.
Ferroic Properties of Highly Dense Multiferroic Bi1−xLa0.05TbxFeO3 Ceramics Via Sheltered Spark Plasma Sintering
Authors: Jiang Qing‐Hui , Mei Ao , Lin Yuan‐Hua , Nan Ce‐Wen , Shen Zhijian
Published: April 2008

Multiferroic Bi0.95−xLa0.05TbxFeO3 (BLTFO) ceramics were prepared by spark plasma sintering. The protection of CeO2 powders in the spark plasma sintering process can effectively restrain the valence fluctuation of iron ions and high‐dense BLTFO ceramics with good dielectric and ferroelectric properties are fabricated. The BLTFO ceramics have low loss (tanδ∼5%) between 102 and 106 Hz. The doping of Tb can increase the dielectric and ferromagnetic properties, but decrease the ferroelectricity of BLTFO ceramics.
Iron supplementation of iron‐replete Indonesian infants is associated with reduced weight‐for‐age
Authors: Lind Torbjörn , Seswandhana Rosadi , Persson Lars‐Åke , Lönnerdal Bo
Published: April 2008

Background: General iron supplementation to prevent iron deficiency in infants who are iron sufficient when starting supplementation may adversely affect their health.

Objective: A secondary analysis to explore the effect of iron supplementation on iron‐replete (IR; Hb ≥113 g/L and S‐ferritin ≥33 μg/L) or non‐iron‐replete 6‐month‐old Indonesian infants participating in a large, randomized trial on iron and zinc supplementation.

Results: Among the iron‐supplemented IR (Fe‐IR, n = 80) infants S‐ferritin was, compared to non‐iron‐supplemented (NS) IR infants (NS–IR, n = 74), significantly higher (47.5 vs. 20.7 μg/L, p = 0.04), and S‐zinc significantly lower (9.7 vs. 10.5 μmol/L, p = 0.04). Haemoglobin concentration (Hb) did not differ between the Fe‐IR and NS–IR groups. Change in weight‐for‐age z‐score (WAZ) from 6 to 12 months and mean WAZ at 12 months was lower in the Fe‐IR group compared to the NS‐IR group (−1.45 vs. −1.03, p < 0.001 and −1.97 vs. −1.60, p < 0.001, respectively). There was no difference in morbidity between groups. Iron supplementation of non‐iron‐replete infants increased Hb and S‐ferritin, but did not affect S‐zinc or anthropometrical indices.

Conclusion: In our study, iron supplementation of IR infants affected WAZ adversely, whereas iron supplementation to non‐iron‐replete infants did not affect growth. These results support a cautious approach to iron supplementation of IR infants.
Differences in reproductive timing among sponges sharing habitat and thermal regime
Authors: Riesgo Ana , Maldonado Manuel
Published: April 2008

Abstract. The reproductive cycles of four Mediterranean demosponges (Axinella damicornis, Corticium candelabrum, Raspaciona aculeata, and Chondrosia reniformis) were investigated during 2 consecutive years. Three of the species had annual gametogenic cycles characterized by a single peak of gamete production, but members of C. candelabrum showed continuous oocyte production during the 2 years. The relationship between gametogenic dynamics and seawater temperature varied substantially among species, contrary to the widespread belief that gamete production is associated with seasonal water warming. The annual temperature increase (in June) concurred with oocyte production only in C. reniformis, although maximum temperatures were simultaneous with the production of both oocytes in R. aculeata and sperm in C. reniformis. In contrast, the annual temperature decline in October was associated with both oogenesis in A. damicornis and spermatogenesis in R. aculeata. Spermatogenesis in A. damicornis started after a 5‐month period of low‐temperature values (December–April in 2004 and November–March in 2005). Likewise, in C. candelabrum, spermatogenesis started after a 3‐month period of low‐temperature values (November–February), a period concomitant with a slow increase in oocyte production. These findings reveal that sponge species that cooccur and share similar thermal regimes may differ substantially in their timing of gamete production. If we are to predict the future effects of climate change on marine benthic communities, there is an urgent need to improve our knowledge of the species‐specific relationship between timing of gametogenesis and temperature, at least for those sponges that are key species in benthic communities.
Discovery of two magnetic massive stars in the Orion Nebula Cluster: a clue to the origin of neutron star magnetic fields?
Authors: Petit V. , Wade G. A. , Drissen L. , Montmerle T. , Alecian E.
Published: April 2008

The origin of the magnetic fields in neutron stars, and the physical differences between magnetars and strongly magnetized radio pulsars are still under vigorous debate. It has been suggested that the properties of the progenitors of neutron stars (the massive OB stars), such as rotation, magnetic fields and mass, may play an important role in the outcome of core collapse leading to Type II supernovae. Therefore, knowing the magnetic properties of the progenitor OB stars would be an important asset for constraining models of stellar evolution leading to the birth of a neutron star. We present here the beginning of a broad study with the goal of characterizing the magnetic properties of main-sequence massive OB stars. We report the detection of two new massive magnetic stars in the Orion Nebula Cluster: Par 1772 (HD 36982) and NU Ori (HD 37061), for which the estimated dipole polar strengths, with 1σ error bars, are 1150+320ȡ200 and 620+220−170 G, respectively.
Vertebral heart scale in the beagle dog
Authors: Kraetschmer S. , Ludwig K. , Meneses F. , Nolte I. , Simon D.
Published: April 2008

Objective:To determine if Buchanan’s vertebral heart scale can be applied to beagle dogs to establish reference values for this breed and to determine the possible influence of optimal lung inflation on the cardiac measurements.

Methods:The cardiac health of 19 beagle dogs was examined by echocardiography, electrocardiogram, non‐invasive blood pressure measurement, complete blood count and serum chemistry profile. Right and left lateral recumbent radiographs of the thorax were obtained while the dogs were conscious and while under general anaesthesia with optimal lung inflation. The vertebral heart scale was measured in all radiographs.

Results:The mean (sd) vertebral heart scale in the beagle dogs was 10·3 (0·4) v, showing a significant difference from the mean vertebral heart scale of 9·7 (0·5) v in Buchanan’s original study with dogs of different breeds. Degree of inspiration had no significant effect on the vertebral heart scale.

ClinicalSignificance:The vertebral heart scale provides the veterinarian with a possible way of objectively evaluating canine heart size without having to rely on echocardiography. However, the results should be interpreted critically and breed‐specific differences should be taken into account, especially with values slightly above the reference range.
Anaplastic and aggressive subcutaneous sarcoma in a seven‐month‐old dog
Authors: Ghibaudo G. , Bettini G. , Abramo F.
Published: April 2008

A seven‐month‐old female, Italian hound which was presented with anorexia, dyspnoea and weight loss showed two subcutaneous masses at physical examination. Radiographs showed multiple opacities in the lungs, thorax, liver and spleen, and cytology showed discrete pleomorphic cells, with variable nuclear : cytoplasmic ratio, foamy cytoplasm and round to oval nuclei. Incisional biopsy histology showed the infiltrative proliferation of highly pleomorphic spindle to roundish large cells, discrete or arranged in a storiform pattern, with scattered multinucleated giant cells. Immunohistochemistry exhibited strong positivity for vimentin and mild labelling for α‐smooth muscle actin and lysozyme; other mesenchymal or histiocytic lineage markers stained negatively. Because of the poor prognosis, the owner elected euthanasia. Post‐mortem examination confirmed massive metastatic spread. Cytology, histology and immunohistochemistry suggested the diagnosis of anaplastic sarcoma with giant cells, although disseminated histiocytic sarcoma was a reliable differential diagnosis. The authors underline the difficulties in definitively categorising poorly differentiated sarcomas, even if a large panel of markers is applied.
Willingness to volunteer during an influenza pandemic: perspectives from students and staff at a large Canadian university
Authors: Rosychuk Rhonda J. , Bailey Tracey , Haines Christina , Lake Robert , Herman Benjamin , Yonge Olive , Marrie Thomas J.
Published: April 2008

Background  A future influenza pandemic will require greater demand on numerous essential services and a reduced capacity to meet that demand. Recruitment of volunteers is an important issue for pre‐pandemic planning.

Objectives  To identify factors and attitudes towards volunteerism in the event of a pandemic of influenza.

Participants/methods  A 42‐item web‐questionnaire was administered to all faculty, staff and students at the University of Alberta. Respondents indicated their willingness to volunteer. Responses were dichotomized and logistic regression models were developed to capture the association between willingness to volunteer and (i) demographic and information source variables, (ii) risk perception and general knowledge, and (iii) volunteering attitudes and priority access variables.

Results  Many factors predicted willingness to volunteer and several involved interactions with other variables. Individuals who were older, relied on University Health Centre information and who had past volunteerism experience were generally more likely to be willing to volunteer. Those willing to volunteer were more likely to think spread could be prevented by covering mouth when coughing/sneezing, and treatment would include drinking fluids. Those who thought influenza would be treated by antibiotics were less willing to volunteer. Likely volunteers thought that healthcare students should be encouraged to volunteer if there was a healthcare worker shortage.

Conclusion  This study provides guidance for those who are preparing universities to deal with pandemic influenza. The results suggest factors that might be important in the recruitment of volunteers during an influenza pandemic and these factors might be relevant for other sectors as well.
Presence of Rhodopsin and Porphyropsin in the Eyes of 164 Fishes, Representing Marine, Diadromous, Coastal and Freshwater Species—A Qualitative and Comparative Study†
Authors: Toyama Mina , Hironaka Mantaro , Yamahama Yumi , Horiguchi Hiroko , Tsukada Osamu , Uto Norihiko , Ueno Yuka , Tokunaga Fumio , Seno Keiji , Hariyama Takahiko
Published: April 2008

There are two types of visual pigments in fish eyes; most marine fishes have rhodopsin, while most freshwater fishes have porphyropsin. The biochemical basis for this dichotomy is the nature of the chromophores, retinal (A1) and 3‐dehydroretinal (A2), each of which is bound by an opsin. In order to study the regional distribution of these visual pigments, we performed a new survey of the visual pigment chromophores in the eyes of many species of fish. Fish eyes from 164 species were used to examine their chromophores by high‐performance liquid chromatography—44 species of freshwater fish, 20 of peripheral freshwater fish (coastal species), 10 of diadromous fish and 90 of seawater fish (marine species) were studied. The eyes of freshwater fish, limb freshwater fish and diadromous fish had both A1 and A2 chromophores, whereas those of marine fish possessed only A1 chromophores. Our results are similar to those of previous studies; however, we made a new finding that fish which live in freshwater possessed A1 if living near the sea and A2 if living far from the sea if they possessed only one type of chromophore.
In Vivo Measurement of Vascular Modulation in Experimental Tumors Using a Fluorescent Contrast Agent
Authors: Valentini Gianluca , D’Andrea Cosimo , Ferrari Raffaele , Pifferi Antonio , Cubeddu Rinaldo , Martinelli Michele , Natoli Claudia , Ubezio Paolo , Giavazzi Raffaella
Published: April 2008

We compared the effectiveness of three optical techniques based on fluorescence imaging and spectroscopy with indocyanine green (ICG) contrast agent to evaluate in vivo the disruption of the active vasculature induced by a vascular targeting agent. The blood perfusion of the MDA‐MB‐435 tumor model transplanted in nude mice was estimated from the signal of the contrast agent measured immediately after its systemic injection in mice. Optical measurements were performed using a fluorescence imaging setup and a fiber‐based time correlated single photon counting (TCSPC) apparatus. This latter apparatus was used to measure the tumor fluorescence in transmittance geometry and the change in the basal optical absorption induced by the contrast agent, thus providing an alternative estimation of the blood content in the tumor. Mice were divided into four groups. Three groups were treated with different doses of the vascular disrupting agent ZD6126, the fourth group (control group) received the drug vehicle only. Optical measurements were carried out 3 h after pharmacologic treatment. After 24 h, mice were killed, tumors were excised and the extent of necrosis was evaluated with standard histologic analysis. On fluorescence imaging ICG emission from tumors of mice treated with ZD6126 significantly was lower compared with the emission from control mice. The histologic sections also showed a significantly higher amount of necrosis in tumors of treated mice. Both these findings, which correlate with each other, indicate an effective vascular shutdown induced by the drug. However, ICG fluorescence measured with the TCSPC apparatus in transmittance geometry and the estimate of the change in optical absorption did not allow a statistically significant differentiation between treated and control groups.
Vision-Based Weld Pool Width Control
Authors: Pietrzak K. A. , Packer S. M.
Published: April 2008

Methods for controlling weld penetration for arc welding processes from top-side measurements have long been sought. One indirect variable that has been reported to correlate with penetration is weld pool geometry. A system which uses weld pool geometry sensing for controlling weld penetration is described in this paper. The system uses a miniature camera mounted in a modified coaxial viewing torch to view the weld pool. A robust machine vision algorithm has been developed for this system to measure weld pool width. The algorithm was designed to locate the edges of the weld pool despite the presence of other edges caused by the heat affected zone, scratches, marks, and weld pool impurities. The algorithm uses a matched edge filter and a majority voting scheme to measure the width of the pool. A control system was developed to regulate weld pool width in the presence of disturbances caused by such items as incorrect parameter settings, small variations in material composition, and material thickness changes. Experiments were conducted to test the control system by simulating some of these disturbances. The experiments demonstrated that for certain classes of materials, this technique works quite well. However, for other materials such as stainless steel 304, surface impurities in the weld pool visually obscure the weld pool and its edges to such a degree that the system fails to lock onto the edges of the pool.
On the Effect of the U-O-E Manufacturing Process on the Collapse Pressure of Long Tubes
Authors: Kyriakides S. , Corona E. , Fischer F. J.
Published: April 2008

A commonly used process for manufacturing large-diameter tubes for offshore pipeline, riser and tension-leg platform tether applications involves the cold forming of long plates. The plates are bent into a circular shape and then welded. The circumference of the pipe is then plastically expanded to develop a high tolerance circular shape. Collectively, these steps comprise the U-O-E manufacturing process. These mechanical steps cause changes in the material properties and introduce residual stresses in the finished pipe. This paper presents the results of a combined experimental and analytical study of the effect on the U-O-E process on the capacity of the tube to resist collapse under external pressure loading. The U-O-E manufacturing process for a 26 in. (660 mm) diameter, 1.333 in. (33.86 mm) wall thickness pipe was simulated numerically. The numerical process was validated by comparing the predicted stress-strain behavior of the material at two stages in the process with properties measured from actual pipe specimens obtained from the mill. Following the simulation of the U-O-E process the collapse pressure was calculated numerically. The manufacturing process was found to significantly reduce the collapse pressure. A similar pipe for which the final sizing was conducted (simulated) with circumferential contraction (instead of expansion) was found not to have this degradation in collapse pressure.
Self-Organizing Neural Network Application to Drill Wear Classification
Authors: Govekar E. , Grabec I.
Published: April 2008

The article describes an application of a simulated neural network to drill wear classification from cutting force signals generated by the drilling process. As the input to the neural network, a multicomponent vector composed of a sensory part and a descriptive part is used. The components of the sensory part represent characteristic features of the cutting momentum and the feed force power spectra, while the descriptive part encodes the corresponding drill wear class. During adaptation, the self-organizing neural network is used to form a set of prototype vectors representing an empirical model of the observed drilling process. The model is used in the analysis mode of the system for an on-line classification of the drill wear from the cutting forces. The performance of the developed information processing system is experimentally demonstrated by classification of drill wear during machining on a steel workpiece.
Design of Flexible Grinding Wheel With Variable Hub Thickness
Authors: Bzymek Z. M. , Song G. , Howes T. D. , Garrett R. E.
Published: April 2008

In this paper, various Cubic Boron Nitride (CBN) grinding wheels designed to suppress chatter are statically and dynamically analyzed and compared by means of the Finite Element Method (FEM). As a result of these analyses, a flexible wheel with a variable thickness hub is proposed. Theoretically, the new wheel should suppress chatter and thus be a major step forward in grinding wheel design.
A Model of High Performance Dynamometer
Authors: Chung Y. L. , Spiewak S. A.
Published: April 2008

A narrow frequency bandwidth, strong fluctuations of the gain versus signal frequency and sensitivity to disturbances caused by the operating environments are the most common factors limiting the applicability of sensors in manufacturing systems. Self-tuning filters represent an efficient means of alleviating these limitations. Since the dynamic properties of sensors vary rapidly, a successful implementation of sensors coupled with self-tuning filters hinges upon accurate, real-time adjustments of these filters. The selection of optimum filter settings, based upon the available distorted output signals from the in-process sensors, poses a difficult problem. In general, the algorithm of self tuning requires a priori information about the sensor and its environment, condensed into a form of an analytical model. A systematic approach to the analytical modeling of sensors is proposed. To illustrate this approach, a comprehensive model of a commercial dynamometer is developed and tested.
Modelling and Analysis of Pulse Electrochemical Machining (PECM)
Authors: Kozak J. , Rajurkar K. P. , Wei B.
Published: April 2008

A small interelectrode gap in Electrochemical Machining (ECM) results in improved dimensional accuracy control and simplified tool design. However, using a small gap with conventional ECM equipment adversely affects the electrolyte flow or mass transport conditions in the gap, leading to process instability. The most remarkable breakthrough in this regard is the development of ECM using pulsed current. Pulse Electrochemical Machining (PECM) involves the application of a voltage pulse at high current density in the anodic dissolution process. PECM allows for more precise monitoring and control of machining parameters than ECM using continuous current. Small interelectrode gap, low electrolyte flow rate, gap state recovery during the pulse-off times and improved anodic dissolution efficiency features encountered in PECM lead to improved workpiece precision and surface finish when compared with ECM using continuous current. This paper presents mathematical models for the PECM process which take into consideration the nonsteady physical phenomena in the gap between the electrodes, including the conjugate fields of electrolyte flow velocities, pressure, temperature, gas concentrations, current densities and anodic material removal rates. The principles underlying higher dimensional accuracy and simpler tool design attainable with optimum pulse parameters are also discussed. Experimental studies indicate the validity of the proposed PECM models.
Modelling Machining Dynamics Including Damping in the Tool-Workpiece Interface
Authors: Elbestawi M. A. , Ismail F. , Du R. , Ullagaddi B. C.
Published: April 2008

Machining instability, namely chatter, occurs due to the interaction between the structural dynamics and the cutting process. The process damping generated at the tool-workpiece interface is an important parameter of that interaction. A significant enhancement to the chatter simulation model in milling is presented. It includes tracking of the interference between the tool flank and the generated wavy surface, which is the source of process damping. Results of simulation runs performed to determine the limits of stability are presented for sharp tools as well as for tools with various amount of flank wear. The phase relationship between the ploughing force and tool vibrations is explained using these simulations. It is also shown that the improved model accurately predicts the increase in the limit of stability due to tool wear, as well as the effect of the wave length of the machined surface undulations on process damping. Cutting tests of aluminum confirmed the simulation results.
On the Experimental Optimization of Tool Geometry for Uniform Pressure Distribution in Single Edge Gundrilling
Authors: Astakhov V. P. , Frazao J. , Osman M. O. M.
Published: April 2008

An investigation into the effect of gundrill geometry on the coolant flow, in gundrilling, is carried out. This investigation deals mainly with the loss of coolant pressure occurring in a limited space between the flank of the gundrill and the bottom of the predrilled hole. This space is named as “bottom clearance.” The pressure loss in the bottom clearance is classified into, (a) pressure loss due to flow interaction with the bottom of the drilled hole (impact pressure loss), and (b) pressure loss due to hydraulic resistance of the annular groove connecting the bottom clearance and the chip removal passage. The study indicates that a significant part of the pressure loss occurs due to flow deflection at the bottom of the hole. The reduction of pressure loss can be achieved either by reducing the coolant velocity at the orifice exit, or, by increasing the coolant pressure in the bottom clearance. In this study, the shoulder dub-off angle of the gundrill is experimentally optimized to increase the coolant pressure in the bottom clearance, thereby achieving uniform coolant pressure distribution. This uniform pressure distribution resulted in increased gundrill life without compromising the quality of the machined hole.
Steady-State Formulation for Stress and Distortion of Welds
Authors: Gu M. , Goldak J. A.
Published: April 2008

A steady state formulation has been developed for thermal stress analysis. It uses features from both the Lagrangian formulation and the Eulerian formulation. The mesh sits on an Eulerian frame but deforms as if in the Lagrangian frame. Therefore, it is suitable for steady state problems with free boundaries. History dependent parameters are integrated along flow lines. A significant gain in computing speed and/or spatial resolution over transient analyses has been achieved together with a noticeable reduction for memory requirements. Numerical results are given for a three-dimensional analysis of edge weld.
Tool Wear Monitoring at Turning
Authors: Waschkies E. , Sklarczyk C. , Hepp K.
Published: April 2008

A new method for automatic tool wear monitoring at turning has been developed based on the analysis of the continuous acoustic emission (machining noise) generated by the tool during machining. Different wear types (wear of tool flank face and tool chipping) result in changes in the different characteristic values of the noise signal. In case of a uniform abrasion of the insert, e.g., flank face or crater wear, an increased mean signal level is observed, whereas for microbreakage at the edge, an increase of the crest factor with nearly constant mean signal level is found. The burst-like signals from collision between chip and tool and from chip breakage have to be eliminated from analysis to avoid the distortion of the signal parameters of the continuous acoustic emission. This method should be well suited especially for monitoring of finishing processes (small depth of cut).
Antimicrobial Susceptibilities of Geographically Diverse Clinical Human Isolates ofLeptospira
Authors: Ressner Roseanne A. , Griffith Matthew E. , Beckius Miriam L. , Pimentel Guillermo , Miller R. Scott , Mende Katrin , Fraser Susan L. , Galloway Renee L. , Hospenthal Duane R. , Murray Clinton K.
Published: April 2008

Although antimicrobial therapy of leptospirosis has been studied in a few randomized controlled clinical studies, those studies were limited to specific regions of the world and few have characterized infecting strains. A broth microdilution technique for the assessment of antibiotic susceptibility has been developed at Brooke Army Medical Center. In the present study, we assessed the susceptibilities of 13Leptospiraisolates (including recent clinical isolates) from Egypt, Thailand, Nicaragua, and Hawaii to 13 antimicrobial agents. Ampicillin, cefepime, azithromycin, and clarithromycin were found to have MICs below the lower limit of detection (0.016 μg/ml). Cefotaxime, ceftriaxone, imipenem-cilastatin, penicillin G, moxifloxacin, ciprofloxacin, and levofloxacin had MIC90s between 0.030 and 0.125 μg/ml. Doxycycline and tetracycline had the highest MIC90s: 2 and 4 μg/ml, respectively. Doxycycline and tetracycline were noted to have slightly higher MICs against isolates from Egypt than against strains from Thailand or Hawaii; otherwise, the susceptibility patterns were similar. There appears to be possible variability in susceptibility to some antimicrobial agents among strains, suggesting that more extensive testing to look for geographic variability should be pursued.
Pharmacodynamic Characterization of Ceftobiprole in Experimental Pneumonia Caused by Phenotypically Diverse
Staphylococcus aureus
Strains
Authors: Laohavaleeson Somvadee , Tessier Pamela R. , Nicolau David P.
Published: April 2008

Ceftobiprole (BPR) is an investigational cephalosporin with activity against
Staphylococcus aureus
, including methicillin-resistant
S. aureus
(MRSA) strains. The pharmacodynamic (PD) profile of BPR against
S. aureus
strains with a variety of susceptibility phenotypes in an immunocompromised murine pneumonia model was characterized. The BPR MICs of the test isolates ranged from 0.25 to 2 μg/ml. Pharmacokinetic (PK) studies were conducted with infected neutropenic BALB/c mice; and the BPR concentrations were measured in plasma, epithelial lining fluid (ELF), and lung tissue. PD studies with these mice were undertaken with eight
S. aureus
isolates (two methicillin-susceptible
S. aureus
strains, three hospital-acquired MRSA strains, and three community-acquired MRSA strains). Subcutaneous BPR doses of 2 to 125 mg/kg of body weight/day were administered, and the change in the number of log
10
CFU/ml in lungs was evaluated after 24 h of therapy. The PD profile was characterized by using the free drug exposures (
f
) determined from the following parameters: the percentage of time that the concentration was greater than the MIC (
T
> MIC), the maximum concentration in serum/MIC, and the area under the concentration-time curve/MIC. The BPR PK parameters were linear over the dose range studied in plasma, and the ELF concentrations ranged from 60 to 94% of the free plasma concentration.
fT
> MIC was the parameter that best correlated with efficacy against a diverse array of
S. aureus
isolates in this murine pneumonia model. The 80% effective dose (ED
80
), ED
50
, and stasis exposures appeared to be similar among the isolates studied. BPR exerted maximal antibacterial effects when
fT
> MIC ranged from 6 to 22%, regardless of the phenotypic profile of resistance to β-lactam, fluoroquinolone, erythromycin, clindamycin, or tetracycline antibiotics.
Protective Effect of an Extract fromAscaris suumin Experimental Arthritis Models
Authors: Rocha Francisco Airton Castro , Leite Ana Karine Rocha Melo , Pompeu Margarida Maria Lima , Cunha Thiago Mattar , Verri Waldiceu A. , Soares Fernanda Macedo , Castro Rondinelle Ribeiro , Cunha Fernando Queiroz
Published: April 2008

We investigated the effect of an extract from a helminth (Ascaris suum) in zymosan-induced arthritis (ZYA) or collagen-induced arthritis (CIA). Rats and mice, respectively, received 1 mg and 0.1 mg zymosan intra-articularly (i.a.). Test groups received anA. suumextract either per os (p.o.) or intraperitoneally (i.p.) 30 min prior to i.a. zymosan. Controls received saline. Hypernociception was measured using the articular incapacitation test. Cell influx, nitrite, and cytokine levels were assessed in joint exudates. The synovia and distal femoral extremities were used for histopathology. Cartilage damage was assessed through determining glycosaminoglycan (GAG) content. DBA/1J mice were subjected to CIA. The test group receivedA. suumextract i.p. 1 day after CIA became clinically detectable. Clinical severity and hypernociception were assessed daily. Neutrophil influx was determined using myeloperoxidase activity. TheA. suumextract, either i.p. or p.o., significantly and dose-dependently inhibited cell influx and hypernociception in ZYA in addition to reducing GAG loss and ameliorating synovitis. TheA. suumextract reduced i.a. levels of NO, interleukin-1β (IL-1β), and IL-10 but not tumor necrosis factor alpha (TNF-α) in rats subjected to ZYA while reducing i.a. IL-10, but not IL-1β or TNF-α, levels in mice. Clinically, mice subjected to CIA treated with theA. suumextract had less severe arthritis. Hypernociception, myeloperoxidase activity, and synovitis severity were significantly reduced. These data show that a helminth extract given p.o. protects from arthritis severity in two classical arthritis models. ThisA. suumeffect is species independent and functions orally and parenterally. The results show clinical and structural benefits whenA. suumextract is given either prophylactically or therapeutically.
Phenology of tropical forests: patterns, causes, and consequences
Authors: Reich P. B.
Published: April 2008

Leaf phenology of tropical forests is distinct from other biomes. Unlike the marked temperature-related periodicity of temperate forests, development tends to be continuous in aseasonal lowland tropical rain forests and becomes more episodic in response to increasing annual drought in tropical dry forests. Hence, in tropical rain forests, foliar development (production, senescence, and longevity) is largely under internal rather than environmental control. In contrast, tropical forests with marked annual dry seasons display associated seasonality of leaf production and shedding. This developmental seasonality can be explained by overlaying the influence of seasonality on trees' internally regulated development and appears to be controlled by acclimative physiological processes and not by sensitivity to photo-, thermo-periodic, or direct environmental cues. Consequences of tropical phenology stem from both the variety of leaf and species ecophysiological types common to a given moisture regime and their relative synchrony of development, and include the following: larger diversity of ecophysiological species types in rain than dry forests; differential rates of herbivory in dry than wet seasons and for synchronous versus asynchronous leaf flushes; ecosystems with greater canopy foliar mass per hectare in rain than dry forests; and several leaf adaptations perhaps unique to tropical forests, such as delayed greening and seasonal leaf phenotypes. Tropical forests may vary in sensitivity to predicted climate change. Phenology of rain forests should change little unless water balance changes markedly, and developmental events in rain forests may be relatively insensitive to moderate changes in CO2 or temperature. Phenology of dry forests could be more sensitive, and in opposite directions, to elevated CO2 and temperatures. Elevated CO2 might delay the onset of leaf shedding and stimulate longer life span if stand level transpiration is reduced, whereas higher temperatures could lead to more rapid water depletion, longer leafless periods, and more strongly synchronized phenology. Key words: tropical forests, phenology, leaf life span, herbivory.
Seasonality of flowering and fruiting in temperate forest trees
Authors: Lechowicz Martin J.
Published: April 2008

The phenology of leaf presence and photosynthetic activity together set a potential limit on tree productivity in a seasonal climate; similarly, the seasonal timing of flowering and fruiting can decide tree reproductive success. The capacity for long-term storage of photosynthate appears to override any necessary functional linkage between these two critical aspects of tree phenology. Foliar and reproductive phenology in broadleaf deciduous trees of the temperate zone are only weakly coupled within a growing season, especially in precocious flowering trees that mature their fruits in early summer. In species that fruit in late summer and fall, leaf emergence and flowering can be entrained by shared responses to the progressive warming of early spring but with only limited effect on the timing of fruit maturation. The timing of foliar senescence and fruit maturation is correlated only in fall-fruiting trees but as a common response to fall climate rather than the outcome of foliar retranslocation of resources to developing fruits. The possibility exists that global climate change may disrupt these patterns of foliar and reproductive phenology, but the magnitude of the effect will depend on the poorly studied balance of thermal versus photoperiodic cues for phenological events. Key words: phenology, leaf senescence, bud burst, seed dispersal, global climate change.
Effects of climatic change on trees from cool and temperate regions: an ecophysiological approach to modelling of bud burst phenology
Authors: Hänninen Heikki
Published: April 2008

A framework is presented for modelling bud burst phenology of trees from the cool and temperate regions. Three ecophysiological aspects affecting the timing of bud burst are considered: (i) effects of environmental factors on the rest status of the bud, (ii) effect of rest status on the ability for bud burst, and (iii) direct effect of air temperature on the rate of development towards bud burst. Any model for bud burst phenology can be presented within the framework with three submodels, each of them addressing one of the corresponding three ecophysiological aspects. A total of 96 hypothetical models were synthesized by combining submodels presented in the literature. The models were tested in two experiments with saplings of Pinus sylvestris L. growing in experimental chambers at their natural site in eastern Finland. In the first experiment, air temperature and (or) concentration of atmospheric CO2was elevated. Elevation of the air temperature hastened bud burst, whereas elevation of the concentration of CO2did not affect it. Several models accurately predicted the timing of bud burst for natural conditions but too early for bud burst at the elevated temperatures. This finding suggests that (i) the risk of a premature bud burst with subsequent frost damage, as a result of climatic warming, was overestimated in a recent simulation study, and (ii) bud burst observations in natural conditions alone are not sufficient for the testing of these mechanistic models. Several models did predict the timing of bud burst accurately for all treatments, but none of them obtained sufficiently strong support from the findings to stand out as superior or uniquely correct. In the second experiment a photoperiod submodel for rest break was tested by exposing the saplings to short-day conditions. The short-day treatment had only a minor effect on the timing of bud burst. These results demonstrated the importance of the concept of model realism: the accuracy of a model can be lost in new conditions (e.g., global warming), unless the model correctly addresses the essential ecophysiological aspects of the regulation of timing of bud burst. Key words: annual cycle of development, chilling, dormancy, field test, photoperiod, rest break.
Foliicolous dematiaceous hyphomycetes from Syzygium cordatum
Authors: Crous P. W. , Wingfield M. J. , Kendrick W. B.
Published: April 2008

During a study of foliicolous fungi on Syzygium cordatum in South Africa, several previously undescribed or unreported fungi were collected. Two new species of Anungitea, Anungitea caespitosa and Anungitea syzygii, are described from leaf litter. An additional four new taxa are also described, Chloridium constrictospora, Parasympodiella elongata, and Vermiculariopsiella spiralis from litter, and Podosporium etheldoidgeae from living leaves. Several saprobic fungi are reported for the first time in South Africa. The morphological variation occurring in Conoplea mangenotii is discussed. Key words: foliicolous fungi, Myrtaceae, systematics, Syzygium cordatum.
The surface of Erysiphe graminis and the production of extracellular material at the fungus – host interface during germling and colony development
Authors: Carver T. L. W. , Thomas B. J. , Ingerson-Morris S. M.
Published: April 2008

Low temperature scanning electron microscopy was used to study the development of Erysiphe graminis DC f.sp. avenae Marchal from germination through infection to sporulation of the fungal colony. To clarify resolution of the fungus–host interface and facilitate interpretation of fungal surface structures, epicuticular waxes were removed from host leaves before inoculation. Whereas conidia were covered in spinelike protrusions or globular bodies, young germ tubes, appressoria, and hyphae were initially smooth walled, but by 15 h after inoculation, wartlike bodies, resembling globular bodies on conidia, were present on first appressorial lobes; these increased in number, eventually covering the appressorium surface and appearing on contiguous hyphae. Wartlike bodies also appeared at junctions of hyphal branches, on hyphal appressoria, and on conidiophore basal cells. Their function, if any, is unknown. The meristematic zone, at the apex of the conidiophore basal cell, remained smooth walled, but globular bodies appeared on the wall of young conidia as soon as the limiting septum had formed. Observations with the fungus in situ revealed the presence of amorphous extracellular material around primary germ tubes and appressorial lobes. Extracellular material was also present beneath appressorial germ tubes and hyphae but it was hidden unless the fungus was displaced. It could not be seen beneath conidia. The extracellular material appeared to be adhesive, sticking the fungus firmly to the host surface. Removal of the fungus showed that the extracellular material was deposited close to the tip of developing germ tubes and hyphae. It was particularly thick around primary germ tubes and appressorial lobes, and a discrete ring of extracellular material was often visible around penetration pores (holes in the leaf surface seen beneath primary germ tubes and appressorial lobes). In addition to its adhesive properties, the extracellular material may act as a matrix in which fungal enzymes are sited and focused for attack on the host. Key words: Erysiphe graminis, low temperature scanning electron microscopy, extracellular material, fungal adhesion, fungal surface morphology.
Secretory Synthesis of Active Recombinant Fish Growth Hormone by Insect Cells Using a Baculovirus Vector
Authors: Tsai H. J. , Chen H. M. , Lo C. F.
Published: April 2008

A growth hormone cDNA of yellowfin porgy (Acanthopagrus latus) was inserted into baculovirus vectors, pAcT7, under the control of the polyhedrin promoter. A 22-kilodalton (kDa) protein, similar to that of native growth hormone, was detected in the supernatant of insect cells infected with the recombinant virus at the level of 2–8% of total proteins. This protein was immunoprecipitated with rabbit polyclonal antibodies raised against native chum salmon (Oncorhynchus keta) growth hormone. Furthermore, a radiolabeled protein band of 22 kDa was also seen in the recombinant-virus-infected cell culture supernatant after labeling with [35S]methionine. Injection of individual tilapia with 0.1 μg of crude supernatant protein containing recombinant growth hormone once a week resulted in significant increases (p < 0.01) in weight (54%), weight gain (260%), length (21%), and feed efficiency rate (210%) relative to a similarly treated control group and an untreated control group at week 5 onwards.
Stream Channel Morphology and Woody Debris in Logged and Unlogged Basins of Western Washington
Authors: Ralph Stephen C. , Poole Geoffrey C. , Conquest Loveday L. , Naiman Robert J.
Published: April 2008

Channel morphology and habitat characteristics of stream segments draining unharvested old-growth forests were compared with those from streams within intensively and moderately logged basins. Sites covered a broad geographic range in western Washington State and were stratified by basin area and channel gradient. Although the number of pieces of large woody debris (LWD) within stream channels was unaffected by timber harvest, there was a clear reduction in LWD size in harvested basins. Timber harvest also resulted in a shift in location of LWD towards the channel margins, outside the low-flow wetted width of the channel. Intensive harvest simplified channel habitat by increasing riffle area and reducing pool area and depth, although the commonly used index of pool-to-riffle ratio appears inadequate to document these changes. Given the natural variation from stream to stream, we conclude that simple counts of instream LWD and channel units (habitat types) are not useful as management objectives. Instead, these attributes should be used collectively as indicators of the complexity and stability of in-stream habitat with respect to the specific channel and valley geomorphology.
Mitochondrial DNA and Conservation of an Aboriginal Arctic Char (Salvelinus alpinus oquassa) from Floods Pond, Maine
Authors: Kornfield Irv , Kircheis Frederick W.
Published: April 2008

Periods of low water in Floods Pond, Maine, USA, during spawning seasons for an endemic population of landlocked Arctic char, Salvelinus alpinus oquassa, have contributed to several year-class failures. To determine the genetic uniqueness of these fish, samples of Arctic char from five isolated lakes in New England and eastern Canada were examined by restriction endonuclease analysis of mitochondrial DNA (mtDNA) and compared with samples of lake trout (Salvelinus namaycush) and Arctic char from Scandinavia. Results suggest that (1) Arctic char of eastern North America should all be considered members of Salvelinus alpinus oquassa, (2) char from Floods Pond possess a unique mtDNA banding pattern for one restriction enzyme not observed in fish from any other sampled locality (this difference delineates a distinct lineage of Arctic char whose preservation is warranted on genetic grounds), and (3) unique banding patterns did not characterize any other studied char population, including geographic variants (these populations may be viewed as genetically homogeneous, and none warrant individual protection based upon our genetic characterizations). We contend that genetically identified lineages in the early stages of divergence warrant preservation.
Temporal Variation in Size and Abundance of Juvenile Atlantic Cod (Gadus morhua) at an Inshore Site off Eastern Newfoundland
Authors: Methven David A. , Bajdik Christopher
Published: April 2008

Temporal variability in abundance and size of juvenile Atlantic cod (Gadus morhua) was studied at a shallow-water site in Trinity Bay, Newfoundland, from July 1982 to September 1983 and July 1989 to September 1990. Cod were collected with a small seine during the day and night. 0-group and 1-group cod predominated in the catch. Nighttime catches contained significantly more and larger cod than daytime catches primarily because 1-group cod were only collected at night. 1-group cod were not collected when water temperatures were less than 0 °C or when ice was present. Abundance peaked in August–November and April–June. Pelagic juveniles arrived inshore when water temperatures and salinities were highest (>12 °C, >30 ppt) in August and September and represented ~25–40 and 10%, respectively, of the cod collected at that time. Significantly more cod were collected in 1989–90 than in 1982–83, although water temperatures were not significantly different between the two periods. Sampling by additional fishing gears, including SCUBA observations, supports the hypothesis that 0-group and 1-group cod move into the sampling area at night (or dusk) and that daytime gear avoidance is secondary to diel activity patterns in explaining differences in day and night catches.
Elemental Patterns in Red Hind (Epinephelus guttatus) Otoliths from Bermuda and Puerto Rico Reflect Growth Rate, Not Temperature
Authors: Sadovy Yvonne , Severin Kenneth P.
Published: April 2008

Sodium, sulfur, calcium, and strontium concentrations were measured (with an electron microprobe) across sectioned wild red hind (Epinephelus guttatus) otoliths from Puerto Rico and Bermuda. A single inverse relationship between strontium/calcium (Sr/Ca) ratios and log body growth rate describes the data from both localities. Patterns in Sr/Ca ratios have been used to infer temperature histories of individual fish; our data indicate that there is not a single Sr/Ca-temperature relationship capable of yielding a plausible temperature history across a single otolith, nor is there one that could give reasonable temperature histories for both the Puerto Rico and Bermuda otoliths. Previous findings of Sr/Ca–temperature relationships could be the result of body growth rate being correlated with temperature.