bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental windows and origins of the chemical cues mediating hatching responses to injured conspecific eggs in the common frog (Rana temporaria)
Authors: Mandrillon A.-L. , Saglio P.
Published: May 2008

In amphibians, embryonic exposure to chemical cues resulting from a predation event on conspecific eggs can influence hatching traits. However, there is no information on the precise origin of the active substances, or on the critical period of embryonic development mediating such a process. In this context, common frog ( Rana temporaria L., 1758) eggs were exposed at Gosner stage 2, 16, or 20 to chemical cues simulating predation on whole eggs, jelly envelopes, or embryos. Embryonic movement rate, hatching time, and developmental stage at hatching appeared unaffected by the nature of the treatment. In contrast, the embryonic treatments strongly affected the morphology of hatchlings, with the groups exposed to crushed whole eggs and jelly envelopes showing longer (exposures at stages 16 and 20) and deeper (exposure at stage 20) tails than their unexposed counterparts. In addition, exposure at stage 20 to crushed embryos also produced hatchlings with longer tails than the controls. Thus, morphological plasticity at hatching can result from a relatively short period of embryonic exposure to conspecific chemical cues. This critical period occurs at the completion of neurulation (stage 16), with the most marked effects resulting from an exposure at the last stage of embryonic development (stage 20).
Differences in diving and swimming behavior of pup and juvenile Steller sea lions (Eumetopias jubatus) in Alaska
Authors: Rehberg M. J. , Burns J. M.
Published: May 2008

Reduced juvenile survival caused by prey depletion is one hypothesis for the decline in the western Alaska population of Steller sea lions ( Eumetopias jubatus (Schreber, 1776)). To understand the exposure of young sea lions to these depletions, the swimming and diving behavior of pups, juveniles, and subadults was evaluated relative to prey behavior. Pups made shorter and shallower dives (13 m, 0.9 min) than juveniles or subadults, as expected based on physiological limitations, but juveniles and subadults dived to similar depths and durations (29 m, 1.7 min and 38 m, 2.0 min, respectively). Activity patterns of juveniles and subadults reflected diurnal prey migrations, while pup activity did not. Longitudinal trends in pup dive behavior reflected both physiological and behavioral development, while juvenile dive behaviors reflected seasonal changes in prey availability. Results suggest that adult females must continue to provide nutritional support to pups during winter because of the limited diving ability of these young animals. For this reason, the flexible lactation strategies that allow for longer nursing periods during periods of low prey availability and reduce female fecundity may improve juvenile survival.
Influence of rodent abundance on nesting success of prairie waterfowl
Authors: Brook Rodney W. , Pasitschniak-Arts Maria , Howerter David W. , Messier François
Published: May 2008

Most waterfowl nesting failure in the prairie biome is attributed to predation. However, the contribution of small mammal abundance to the prairie predator–prey cycle and how this affects waterfowl productivity is not known. We modelled seasonal variability of nesting success, including a number of habitat and nest-related variables, to quantify influence of rodent abundance for prairie nesting waterfowl for six study sites in the Prairie Pothole Region of Canada, 1996–1998. We estimated there is a curvilinear relationship between the abundance of meadow voles ( Microtus pennsylvanicus (Ord, 1815)) and the nesting success of ducks. The relationship has characteristics of the alternate prey hypothesis at low vole density and characteristics of the shared prey hypothesis at higher densities. At low vole densities, duck nests appear to be buffered from predation by voles but, at higher densities, nesting success was affected negatively. We recommend that predator–prey dynamics should be included as an integral part of management plans for nesting waterfowl and suggest further research using rigorous experiment design to elucidate mechanisms and pathways responsible for this observed relationship.
Demographic features and habitat preferences of southern pygmy mice (Baiomys musculus) in Colima, Mexico
Authors: Schnell Gary D. , Poindexter Cassie J. , Sánchez-Hernández Cornelio , Romero-Almaraz María de Lourdes , Kennedy Michael L. , Best Troy L. , Wooten Michael C. , Pérez Jiménez Alfredo
Published: May 2008

In Colima, Mexico, we conducted 8-night mark–recapture grid studies of southern pygmy mice ( Baiomys musculus (Merriam, 1892)) in January 2003–2007 in dry deciduous and tropical moist forests. For 40 000 trap-nights, 436 individuals were captured 764 times (comprising 18.6% of small mammals). The male:female ratio was 1:1.37, 82.9% were adults, 51.4% of females were pregnant or lactating, and coastal animals, on average, were heavier than those inland. Females moved farther than males. Baiomys was on 17 of 25 grids (densities 1.82–106.24 individuals/ha). Moon illumination did not affect capture or recapture probabilities, but trap-night did (overall, probability increased 1.66%/night). Grids with Baiomys had less bare ground and a more open canopy. Capture sites had more grass, less dead wood and bare ground, a more open and lower canopy, and greater distance to trees. Logistic regression indicated coastal capture sites had more forbs, grasses, and woody plants, and thicker vegetation at 1 m height with trees being relatively distant. Variables differed somewhat for northern sites, and the equation for all grids included 10 of 14 environmental variables. Baiomys frequented edge of an unimproved road traversing one grid. Baiomys musculus, widespread in Colima, exhibited preference for habitats with relatively dense ground cover and at least a partially open canopy.
FINITE ELEMENT SIMULATION OF THE MOTION PROCESS FOR DEEP-GROOVE BALL BEARING
Authors: RONG QI , LIN TENGJIAO , SHAO YIMIN
Published: May 2008

Considering the radial load and rotational speed of bearing, the finite element (FE) model for dynamic contact of deep-groove ball bearing was established by the software — ANSYS. Based on explicit dynamic finite element method, the nodal displacement, velocity of rolling bearing and stress of rolling element were obtained. Through calculating, it could be seen that the maximum velocity was shown at the contact point between the rolling element and the inner ring, while the minimum velocity was shown at the contact point with outer ring. The maximum equivalent stress and shear stress of the bearing were also occurred at the contact point of raceway, and the inner ring was bigger than the outer ring. The finite element simulation of the motion process for deep-groove ball bearing had a guiding significance to the research of dynamic load between the rolling bearing components as well as the dynamic characteristics of rolling bearing.
MANUFACTURING AND FORMING OF PARTIALLY CLADDED DOUBLE BLANKS
Authors: RAUSCHER BORIS , TROMPETER MICHAEL , TEKKAYA A. ERMAN
Published: May 2008

The paper presents the manufacturing and hydroforming of partially cladded double blanks. This novel, semi-finished product can be produced by partial cold roll-bonded cladding. By printing a separating layer onto the contact surface beforehand, cold roll-bonded cladding, defined blank areas remain unjoined which can be bulged during hydroforming to a complex part. Favorable advantages result from the time and cost effective continuous joining process and the extended potential for a material combination aimed at optimally adapted multi-layer composites. Experimental investigations could prove a good joining strength and assure that the cold roll-bonded cladding does not significantly decrease the formability of the cladded blank material. Considering a heat exchanger and a roof rail, the experimental investigations could prove the producibility of parts based on partially cladded blanks and have shown an adequate shape accuracy of the produced parts.
A FINITE ELEMENT ANALYSIS FOR THE EFFECTS OF PROCESS PARAMETERS AND MATERIAL ANISOTROPY IN THE CYLINDRICAL DEEP DRAWING
Authors: YANG T. S. , HWANG N. C. , SHYU R. F.
Published: May 2008

Deep drawing process, one of sheet metal forming methods, is very useful in industrial field because of its efficiency. The deep drawing process is affected by many material and process parameters, such as the strain-hardening exponent, plastic strain ratio, anisotropic property of blank, friction and lubrication, blank holder force, presence of drawbeads, the profile radius of die and punch, etc. In this paper, a finite element method is used to investigate the cylindrical deep drawing process. The thickness of product and the forming force predicted by current simulation are compared with the experimental data. A finite element method is also used to investigate the maximum forming load and the minimum thickness of products under various process parameter conditions, including the profile radius of die, the clearance between die cavity and punch and the blank holding force. Furthermore, the material anisotropy and process parameters effect on the earing are also investigated.
INNOVATIVE FORMING TECHNOLOGY AS A KEY FOR THE EFFECTIVE MANUFACTURING OF LIGHTWEIGHT STRUCTURES
Authors: TEKKAYA ERMAN , TROMPETER MICHAEL , HOMBERG WERNER
Published: May 2008

Current tends in car body or rail traffic engineering aim at the realization of modern lightweight structures. In this context, demanding technological and economical requirements like the use of high strength materials, the forming of very complex geometries, and the reduction of costs, particularly with regard to low volume production, must be achieved. Novel approaches in the field of sheet metal hydroforming are able to overcome existing limitations of conventional forming technologies and feature a higher potential for an effective manufacturing of lightweight structures. This paper shows the current research work at the Institute of Forming Technology and Lightweight Construction (IUL) in the face of sheet metal hydroforming with a special focus on the design of tool systems.
AUTOMATIC MEASUREMENT OF OIL VOLUME IN CHECKOUT OF OIL PUMPS BASED ON MACHINE VISION
Authors: LIU ZHAO DONG , LIAO QIANG
Published: May 2008

To promote the accuracy and degree of automation in the process of oil measuring, an automatic detection system based on machine vision has been established. In this system, CCD camera is treated as a sensor and it collects image of oil level of the measurement cylinder. After image preprocessing, we improve the Canny margin extraction to achieve a better effect on margin detection. And then we use least-squares fitting to detect the sub-pixels margin line of the image. Finally, we calculate the oil volume.
RESEARCH ON COLLABORATIVE DESIGN SOFTWARE INTEGRATION BASED ON SOA
Authors: HU YAOGUANG , WANG RAO
Published: May 2008

With the rapid development of economic globalization, more and more complex products have to be designed by the cooperation of the designers in different geographic locations. The effective sharing and deployment of collaborative design software are of great significance to enhance the capability of cooperative research and development of products. To solve the problem of software integration for collaborative design in the distributed and heterogeneous environment, a distributed software integration framework for collaborative product design based on Service Oriented Architecture (SOA) was proposed. Based on Web Service technology, a collaborative design platform was built, which encapsulates the functions of Computer Aided Design (CAD), Computer Aided Engineering (CAE), Product Data Management (PDM) and Enterprise Resource Planning (ERP) software to integrate distributed collaborative design software in heterogeneous environment.
A NEW METHOD FOR DESIGN PROCESS KNOWLEDGE MANAGEMENT
Authors: ZHANG SHANHUI , GAO QI , YANG CHAOYING
Published: May 2008

According to the state-of-the-art of design process management, a new management method is presented in this paper. Firstly, a design process is divided into three layers: harmony layer, purpose layer and action layer. Secondly, considering the operation features in every design process layer, tasks are divided into four categories, and the relevant models are proposed subsequently. Finally, the framework of a design guide management system is presented, and an example of engine design process is used to illustrate the efficiency of this method. It is approved that the design guide can accumulate design process knowledge and improve design efficiency.
NUMERICAL SIMULATION STUDY ON WATER-LUBRICATED RUBBER BEARING
Authors: WU XIAOJIN , WANG JIAXU , XIAO KE , ZHU JUANJUAN
Published: May 2008

Water-lubricated rubber bearings are one of the most appropriate bearings for underwater use. Because of the configuration and special application environment, numerical simulation is difficult with FEM software and relevant report is rare. The water lubrication is especially interesting in terms of cost and convenience. As a result of capital cost of water-lubricated rubber bearing and time consuming experiment, the numerical approach with FEM prevails. But owning to the petty gap where lubrication fluid is bounded in, the modeling is very difficult. Three dimensional free modal and stress distribution of the bearing are analyzed in numerical simulating with FEM software. The present work of analyzing model is further worthwhile as the model can give yield results according to experiments. The modal and harmonic analyzing results can be used directly in material design and also the improvement of structure.
DESIGN AND TRIAL OF INTELLIGENT SLIDING BEARING SYSTEM
Authors: YANG YINGXIN , LIN MIN , KUANG YUCHUN , LIU YONG , LIU DEMING
Published: May 2008

A patented intelligent sliding bearing system of roller cone bit is invented to monitor radial wear and to stop the running of bearing automatically when the wear reaches the predetermined limit so as to prevent the wear-induced cone loss by early warning. In this paper, the basic operating mechanism of new bearing is stated and discussed. A series of tests are conducted to investigate the mechanical features and the reliability of the new bearing system. The performance of the system is proven to be adequate by the test results.
SOFT SENSOR MODELING FOR VACUUM OIL PURIFICATION MACHINE BASED ON LSSVM
Authors: LI CHUAN , WANG SHILONG , ZHANG XIANMING , KANG LING , MIN JIANJUN
Published: May 2008

According to the secondary variables acquired from industrial processes, a Least Squares Support Vector Machine (LSSVM) based model is proposed for the primary variable soft sensing. The Rough Sets Theory is firstly employed to compress values and attributes of the secondary variables. Then the LSSVM is delivered for the primary variable nonlinear estimating. The method is applied for the vacuum oil purification machine. The moisture content in oil, a hard-to-be-measured primary variable, is computed from the soft sensor model. The result shows that the proposed method features a faster and more precise approximation ability.
EXPERIMENTAL STUDY OF MICROTUBE FLAME TEMPERATURE MEASUREMENT BASED ON EMISSION SPECTRA
Authors: DENG DAQIANG , ZHANG LI , CHEN WEIJUN , QIN LAN , WANG YINZHANG
Published: May 2008

Two methods used for microtube temperature calculation through outer microtube emission spectra are presented. The emission spectra of microtube flame and the outer flame are measured by a CCD fiber spectrometer in the same environment, and the outer flame temperature is measured by thermocouple simultaneity. Outer microtube flame spectra act as referenced spectra. In the first method, spectra correction coefficients are calculated with some wavelengths of referenced spectra. With the functional relationship between the wavelength and the emissivity in the referenced spectra, microtube flame temperature is computed from the emission spectra in the other method. The flame temperature is calculated by the methods on the spectra measurement data.
INNOVATION STUDY ON HIGH PERFORMANCE FILTER TRANSMISSION MECHANISM
Authors: WANG JIAXU , XIAO KE , LI MIN , TANG FENG
Published: May 2008

The paper mainly aims at the common problems existing in driving components, especially in harmonic reducer, RV reduction gear, etc. The paper put forward a new high performance filter transmission mechanism with high reliability, long life, large torque, small volume and lower weight, especially the innovation design method of high performance filter transmission mechanism. The new transmission mechanism is composed of eccentric sleeve, inner meshed planet gear pair of less teeth difference, filter spline pair, three ways thrust bearing and so on. Moreover, the paper has designed the eccentricity and tooth outline, made numerical simulation of the meshing process with pressure angle of 30, calculated the transmission efficiency, and checked the intensity of wheels. Furthermore, the paper has operated comprehensive tests about transmission precision, rigidity, backlash, and transmission efficiency.
CRITERIA FOR TOOL DESIGN IN HYDROFORMING
Authors: VOGLER FALKO , GROCHE PETER
Published: May 2008

Closing forces and internal pressure lead to stresses and strains in hydroforming dies. The deflection of the die influences the accuracy of the hydroformed products. The influence of the die geometry on stresses and strains in the die is being examined fundamentally. Additionally, the location of the closing force transmission is discovered to be crucial. The objectives of this research were to determine the demands on the hydroforming die and to reduce failure-critical stresses.
A NEW MIXED-INTEGRATED APPROACH TO CONTROL AND IMPROVED WELDED QUALITY OR SURFACING LAYER PROPERTY IN THREE GAS SHIELD ARC WELDING PROCESSES
Authors: LUO JIAN
Published: May 2008

This article introduces three new electromagnetic field control welding and the surface welding technique, namely the gas shield metal arc surfacing technique with electromagnetic stirring and electromagnetic treating (EMS-EMT), the gas shield arc welding technique with dual-frequency electromagnetic field controlling (DF-EMS), and the electromagnetic stirring electrogas arc welding technique (EMS-EGW). The principles and characteristics of three welding processes are explained. The engineering application, basic research direction and development of these welding techniques are pointed out and discussed in this article.
ANALYSIS OF THE STRUCTURAL PERFORMANCE AND STRETCHING PROCESS OF THE HONEYCOMB PAPER CORE
Authors: YING FUQIANG , ZHOU LINHANG , WANG LI
Published: May 2008

Honeycomb paper core stretching is an important process in paper core manufacture because the performance and the quality of paperboard are greatly enhanced when the honeycomb hole is stretched to a regular hexagon structure. In view of the above, first the finite element method is used to compare the mechanical performances of honeycomb paperboards of different aperture ratios, and the aperture ratio, which has an important influence on the performance of the honeycomb paper, is explained. Next, a paper core stretching simulation is carried out by means of the dynamic software; thus the variation trend of the stretching force, the stretching speed, and the lateral shrinkage needed in paper core manufacture of different specifications can be obtained. This research can provide useful instruction in the actual manufacture of honeycomb paper core.
A NEUTROSOPHIC DESCRIPTION LOGIC
Authors: WANG HAIBIN , ROGATKO ANDRÉ , SMARANDACHE FLORENTIN , SUNDERRAMAN RAJSHEKHAR
Published: May 2008

Description Logics (DLs) are appropriate, widely used, logics for managing structured knowledge. They allow reasoning about individuals and concepts, i.e. set of individuals with common properties. Typically, DLs are limited to dealing with crisp, well defined concepts. That is, concepts for which the problem whether an individual is an instance of it is a yes/no question. More often than not, the concepts encountered in the real world do not have a precisely defined criteria of membership: we may say that an individual is an instance of a concept only to a certain degree, depending on the individual's properties. The DLs that deal with such fuzzy concepts are called fuzzy DLs. In order to deal with fuzzy, incomplete, indeterminate and inconsistent concepts, we need to extend the capabilities of fuzzy DLs further.

In this paper, we will present an extension of fuzzy [Formula: see text], combining Smarandache's neutrosophic logic with a classical DL. In particular, concepts become neutrosophic (here neutrosophic means fuzzy, incomplete, indeterminate and inconsistent), thus, reasoning about such neutrosophic concepts is supported. We will define its syntax, its semantics, describe its properties and present a constraint propagation calculus for reasoning.
BEST PLAY IN FANORONA LEADS TO DRAW
Authors: SCHADD MAARTEN P. D. , WINANDS MARK H. M. , UITERWIJK JOS W. H. M. , HERIK H. JAAP VAN DEN , BERGSMA MAURICE H. J.
Published: May 2008

Fanorona is the national board game of Madagascar. The game's complexity is approximately the same as that of checkers. In this article, we present a search-based approach for weakly solving this game. It is a well-chosen combination of Proof-Number search and endgame databases. Retrograde analysis is used to generate the endgame databases in which every position with 7 or fewer pieces on the board has been solved. Then, a Proof-Number search variant, PN2, exploits the databases to prove that the game-theoretical value of the initial position is a draw. Future research should develop techniques for strongly solving the game.
MONTE CARLO GO CAPTURING TACTIC SEARCH
Authors: ZHANG PEIGANG , CHEN KEH-HSUN
Published: May 2008

This paper is an extended version of the authors' paper12 presented at JCIS 2007. Standard Monte Carlo UCT tree search algorithm is modified and extended to provide an efficient Go capturing problem solver. Experimental results show that this method outperforms traditional tree search methods to solve capturing problems in Go.
The role of hepatic arterial flow on portal venous and hepatic venous wedged pressure in the isolated perfused CCl4-cirrhotic liver
Authors: Zipprich Alexander , Loureiro-Silva Mauricio R. , D'Silva Irita , Groszmann Roberto J.
Published: May 2008

In cirrhosis, hepatic venous pressure gradient is used to measure portal venous and sinusoidal pressures, as well as drug-induced decreases of elevated pressures. The aim of this study was to investigate the influence of hepatic arterial flow (HAF) changes on portal venous perfusion (PVPP) and wedged hepatic venous pressure (WHVP). Normal and CCl4-cirrhotic rats were subjected to a bivascular liver perfusion with continuous measurements of PVPP, WHVP, and hepatic arterial perfusion pressure. Flow-pressure curves were performed with the use of different flows either through the portal vein (PVF: 20–32 ml/min) or HAF (5–15 ml/min). Increases in HAF lead to significant absolute and relative increases in PVPP ( P = 0.002) and WHVP ( P < 0.001). Absolute changes in HAF correlated to absolute changes in PVPP (cirrhosis: r = 0.64, P < 0.001; control: r = 0.67, P < 0.001) and WHVP (cirrhosis: r = 0.71, P < 0.001; control: r = 0.82, P < 0.001). Changes in PVPP correlated to changes in WHVP due to changes in PVF only in cirrhosis ( r = 0.75, P < 0.001), whereas changes in HAF correlated in both cirrhosis ( r = 0.92, P < 0.001) and control ( r = 0.77, P < 0.001). In conclusion, increases and decreases in HAF lead to respective changes in PVPP and WHVP. This suggests a direct influence of HAF on PVPP and WHVP most likely due to changes in sinusoidal perfusion.
Ostα-Ostβ is required for bile acid and conjugated steroid disposition in the intestine, kidney, and liver
Authors: Ballatori Nazzareno , Fang Fang , Christian Whitney V. , Li Na , Hammond Christine L.
Published: May 2008

Mice deficient in the organic solute transporter (Ost)-α subunit of the heteromeric organic solute and steroid transporter, Ostα-Ostβ, were generated and were found to be viable and fertile but exhibited small intestinal hypertrophy and growth retardation. Bile acid pool size and serum levels were decreased by more than 60% in Ostα−/− mice, whereas fecal bile acid excretion was unchanged, suggesting a defect in intestinal bile acid absorption. In support of this hypothesis, when [3H]taurocholic acid or [3H]estrone 3-sulfate were administered into the ileal lumen, absorption was lower in Ostα−/− mice. Interestingly, serum cholesterol and triglyceride levels were also ∼15% lower in Ostα−/− mice, an effect that may be related to the impaired intestinal bile acid absorption. After intraperitoneal administration of [3H]estrone 3-sulfate or [3H]dehydroepiandrosterone sulfate, Ostα−/− mice had higher levels of radioactivity in their liver and urinary bladder and less in the duodenum, indicating altered hepatic, renal, and intestinal disposition. Loss of Ostα was associated with compensatory changes in the expression of several genes involved in bile acid homeostasis, including an increase in the multidrug resistance-associated protein 3, ( Mrp3)/ Abcc3, an alternate basolateral bile acid export pump, and a decrease in cholesterol 7α-hydroxylase, Cyp7a1, the rate-limiting enzyme in bile acid synthesis. The latter finding may be explained by increased ileal expression of fibroblast growth factor 15 ( Fgf15), a negative regulator of hepatic Cyp7a1 transcription. Overall, these findings provide direct support for the hypothesis that Ostα-Ostβ is a major basolateral transporter of bile acids and conjugated steroids in the intestine, kidney, and liver.
Long-term administration of antisense oligonucleotides into the paraspinal muscles of mdx mice reduces kyphosis
Authors: Laws Nicola , Cornford-Nairn Renée A. , Irwin Nicole , Johnsen Russell , Fletcher Susan , Wilton Stephen D. , Hoey Andrew J.
Published: May 2008

The mdx mouse model of muscular dystrophy has a premature stop codon preventing production of dystrophin. This results in a progressive phenotype causing centronucleation of skeletal muscle fibers, muscle weakness, and fibrosis and kyphosis. Antisense oligonucleotides alter RNA splicing to exclude the nonsense mutation, while still maintaining the open reading frame to produce a shorter, but partially functional dystrophin protein that should ameliorate the extent of pathology. The present study investigated the benefits of chronic treatment of mdx mice by once-monthly deep intramuscular injections of antisense oligonucleotides into paraspinal muscles. After 8 mo of treatment, mdx mice had reduced development of kyphosis relative to untreated mdx mice, a benefit that was retained until completion of the study at 18 mo of age (16 mo of treatment). This was accompanied by reduced centronucleation in the latissimus dorsi and intercostals muscles and reduced fibrosis in the diaphragm and latissimus dorsi. These benefits were accompanied by a significant increase in dystrophin production. In conclusion, chronic antisense oligonucleotide treatment provides clear and ongoing benefits to paralumbar skeletal muscle, with associated marked reduction in kyphosis.
Residual force enhancement exceeds the isometric force at optimal sarcomere length for optimized stretch conditions
Authors: Lee Eun-Jeong , Herzog Walter
Published: May 2008

Residual force enhancement (FE) following stretch of an activated muscle is a well accepted property of skeletal muscle contraction. However, the mechanism underlying FE remains unknown. A crucial assumption on which some proposed mechanisms are based is the idea that forces in the enhanced state cannot exceed the steady-state isometric force at a sarcomere length associated with optimal myofilament overlap. Although there are a number of studies in which forces in the enhanced state were compared with the corresponding isometric forces on the plateau of the force-length relationship, these studies either did not show enhanced forces above the plateau or, if they did, they lacked measurements of sarcomere lengths confirming the plateau region. Here, we revisited this question by optimizing stretch conditions and measuring the average sarcomere lengths in isolated fibers, and we found that FE exceeded the maximal isometric reference force obtained at the plateau of the force-length relationship consistently (mean ± SD: 4.8 ± 2.1%) and by up to 10%. When subtracting the passive component of FE from the total FE, the enhanced forces remained greater than the isometric plateau force (mean ± SD: 4.3 ± 2.0%). Calcium-induced increases in passive forces, known to be present in single fibers and myofibrils, are too small to account for the FE observed here. We conclude that FE cannot be explained exclusively with a stretch-induced development of sarcomere length nonuniformities, that FE in single fibers may be associated with the recruitment of additional contractile force, and that isometric steady-state forces in the enhanced state are not uniquely determined by sarcomere lengths.
Role of the calcium-calpain pathway in cytoskeletal damage after eccentric contractions
Authors: Zhang Bao-Ting , Yeung Simon S. , Allen David G. , Qin Ling , Yeung Ella W.
Published: May 2008

The mechanism(s) underlying eccentric damage to skeletal muscle cytoskeleton remain unclear. We examined the role of Ca2+ influx and subsequent calpain activation in eccentric damage to cytoskeletal proteins. Eccentric muscle damage was induced by stretching isolated mouse muscles by 20% of the optimal length in a series of 10 tetani. Muscle force and immunostaining of the cytoskeletal proteins desmin, dystrophin, and titin were measured at 5, 15, 30, and 60 min after eccentric contractions and compared with the control group that was subjected to 10 isometric contractions. A Ca2+-free solution and leupeptin (100 μM), a calpain inhibitor, were applied to explore the role of Ca2+ and calpain, respectively, in eccentric muscle damage. After eccentric contractions, decreases in desmin and dystrophin immunostaining were apparent after 5 min that accelerated over the next 60 min. Increased titin immunostaining, thought to indicate damage to titin, was evident 10 min after stretch, and fibronectin entry, indicating membrane disruption, was evident 20 min after stretch. These markers of damage also increased in a time-dependent manner. Muscle force was reduced immediately after stretch and continued to fall, reaching 56 ± 2% after 60 min. Reducing extracellular calcium to zero or applying leupeptin minimized the changes in immunostaining of cytoskeletal proteins, reduced membrane disruption, and improved the tetanic force. These results suggest that the cytoskeletal damage and membrane disruption were mediated primarily by increased Ca2+ influx into muscle cells and subsequent activation of calpain.
Physical organisation of simple sequence repeats (SSRs) in Triticeae: structural, functional and evolutionary implications
Authors: Cuadrado A. , Cardoso M. , Jouve N.
Published: May 2008

A significant fraction of the nuclear DNA of all eukaryotes is occupied by simple sequence repeats (SSRs) or microsatellites. This type of sequence has sparked great interest as a means of studying genetic variation, linkage mapping, gene tagging and evolution. Although SSRs at different positions in a gene help determine the regulation of expression and the function of the protein produced, little attention has been paid to the chromosomal organisation and distribution of these sequences, even in model species. This review discusses the main achievements in the characterisation of long-range SSR organisation in the chromosomes of Triticum aestivum L., Secale cereale L., and Hordeum vulgare L. (all members of Triticeae). We have detected SSRs using an improved FISH technique based on the random primer labelling of synthetic oligonucleotides (15–24 bases) in multi-colour experiments. Detailed information on the presence and distribution of AC, AG and all the possible classes of trinucleotide repeats has been acquired. These data have revealed the motif-dependent and non-random chromosome distributions of SSRs in the different genomes, and allowed the correlation of particular SSRs with chromosome areas characterised by specific features (e.g., heterochromatin, euchromatin and centromeres) in all three species. The present review provides a detailed comparative study of the distribution of these SSRs in each of the seven chromosomes of the genomes A, B and D of wheat, H of barley and R of rye. The importance of SSRs in plant breeding and their possible role in chromosome structure, function and evolution is discussed.
A cytogenetic view of sex chromosome evolution in plants
Authors: Armstrong S.J. , Filatov D.A.
Published: May 2008

The recent origin of sex chromosomes in plant species provides an opportunity to study the early stages of sex chromosome evolution. This review focuses on the cytogenetic aspects of the analysis of sex chromosome evolution in plants and in particular, on the best-studied case, the sex chromosomes in Silene latifolia. We discuss the emerging picture of sex chromosome evolution in plants and the further work that is required to gain better understanding of the similarities and differences between the trends in animal and plant sex chromosome evolution. Similar to mammals, suppression of recombination between the X and Y in S. latifolia species has occurred in several steps, however there is little evidence that inversions on the S. latifolia Y chromosome have played a role in cessation of X/Y recombination. Secondly, in S. latifolia there is a lack of evidence for genetic degeneration of the Y chromosome, unlike the events documented in mammalian sex chromosomes. The insufficient number of genes isolated from this and other plant sex chromosomes does not allow us to generalize whether the trends revealed on S. latifolia Y chromosome are general for other dioecious plants. Isolation of more plant sex-linked genes and their cytogenetic mapping with fluorescent in situ hybridisation (FISH) will ultimately lead to a much better understanding of the processes driving sex chromosome evolution in plants.
The use of repetitive DNA in cytogenetic studies of plant sex chromosomes
Authors: Kazama Y. , Matsunaga S.
Published: May 2008

The structure of sex chromosomes in plants was analyzed by fluorescent in situ hybridization (FISH) with repetitive DNAs. FISH probes were successfully obtained from DNA libraries that were amplified from microdissected sex chromosomes. Some probes hybridized to the subtelomeric regions, where many kinds of repetitive DNAs are located with intrachromosomal similarity of their repeat units rather than interchromosomal similarity. For example, FISH with the subtelomeric repetitive sequence can easily show the location of the pseudoautosomal region (PAR) on the X chromosome of Silene latifolia. The other probes were localized on the interstitial region of the sex chromosomes. The interstitial region contains chloroplast DNAs or neighboring sequences of the internal telomeres, suggesting insertion or translocation occurred during differentiation of the sex chromosome. These data are very informative for understanding the structure of the plant sex chromosomes and their evolutionary process.
Chromosomes with a life of their own
Authors: Jones R.N. , González-Sánchez M. , González-García M. , Vega J.M. , Puertas M.J.
Published: May 2008

B chromosomes (Bs) can be described as ‘passengers in the genome’, a term that has been used for the repetitive DNA which comprises the bulk of the genome in large genome species, except that Bs have a life of their own as independent chromosomes. As with retrotransposons they can accumulate in number, but in this case by various processes of mitotic or meiotic drive, based on their own autonomous ways of using spindles, especially in the gametophyte phase of the life cycle of flowering plants. This selfish property of drive ensures their survival and spread in natural populations, even against a gradient of harmful effects on the host plant phenotype. Bs are inhabitants of the nucleus and they are subject to control by ‘genes’ in the A chromosome (As) complement. This interaction with the As, together with the balance between drive and harmful effects makes a dynamic system in the life of a B chromosome, notwithstanding the fact that we are only now beginning to unravel the story in a few favoured species. In this review we concentrate mainly on recent developments in the Bs of rye and maize, two of the species currently receiving most attention. We focus on their population dynamics and on the molecular basis of their structural organisation and mechanisms of drive, as well as on their mode of origin and potential applications in plant biotechnology.
The cytogenetics of homologous chromosome pairing in meiosis in plants
Authors: Bozza C.G. , Pawlowski W.P.
Published: May 2008

Three activities hallmark meiotic cell division: homologous chromosome pairing, synapsis, and recombination. Recombination and synapsis are well-studied but homologous pairing still holds many black boxes. In the past several years, many studies in plants have yielded insights into the mechanisms of chromosome pairing interactions. Research in several plant species showed the importance of telomere clustering on the nuclear envelope (telomere bouquet formation) in facilitating alignment of homologous chromosomes. Homologous pairing was also shown to be tied to the early stages of recombination by mutant analyses in Arabidopsis and maize. In contrast, little is known about the mechanisms that guide homolog interaction after their rough alignment by the bouquet and before the close-range recombination-dependent homology search. The relatively large and complex genomes of plants may require additional mechanisms, not needed in small genome eukaryotes, to distinguish between local homology of duplicated genes or transposable elements and global chromosomal homology. Plants provide an excellent large genome model for the study of homologous pairing and dissection of this process.
Posterior-Segment Surgeries with a Two-Port Modified Multiport Illumination System
Authors: Er Hamdi , Fırat Penpegül
Published: May 2008

Purpose: The purpose of this study was to evaluate the safety and efficacy of a modified two-port multiport illumination system (MIS) in different vitreoretinal surgeries. Patients and Methods: Sixty-one patients had undergone pars plana vitrectomy for complications of retinal diseases with the modified MIS. Only two-port pars plana vitrectomy was performed with the MIS. Visual acuity, intraoperative and postoperative complications, intraocular pressure and the retinal reattachment rate were evaluated. The mean follow-up time was 3 months (range 1–6 months). Results: Visual acuity was stabilized in 40 (65.5%) of 61 eyes, improved in 15 eyes (24.5%) and deteriorated in 6 eyes (9.8%). No intraoperative complications occurred. Postoperative complications were hypotony in 12 eyes, rehemorrhage in 2 eyes and choroidal detachment in 1 eye. Five cases required conversion to standard three-port vitrectomy. Mean overall preoperative and postoperative intraocular pressures were 17.4 and 11.9 mm Hg, respectively. Conclusion: Despite some limitations the modified MIS with two-port sclerotomy is a good, comfortable and safe option for posterior-segment surgeries.
Isolates and Antibiotic Sensitivity of Eighty Culture-Proven Endophthalmitis Cases from Istanbul
Authors: Eser Ilker , Kapran Ziya , Altan Tugrul , Ozel Karatas Meltem , Aydin Derya , Okaygun Eda , Yilmaz Omer Faruk
Published: May 2008

Purpose: To investigate the spectrum of organisms causing endophthalmitis and their sensitivity to commonly used antimicrobial agents. Methods: Medical records of 80 consecutive patients treated at Beyoglu Eye Hospital for endophthalmitis from January 2001 to April 2006 were reviewed. Specimens were obtained from either the vitreous (93%, 81/87) or anterior chamber (7%, 6/87) during pars plana vitrectomy or vitreous tap, and were inoculated into blood culture bottles. A Kirby-Bauer disk diffusion test was performed to determine antibiotic susceptibility. The outcome measures included isolates identified and antibiotic sensitivity of the specimens. Results: Fifty-six of 87 (64.4%) isolates were Gram-positive organisms, 29 (33.3%) were Gram-negative organisms, and 2 (2.3%) were fungi. The most common organism group identified was coagulase-negative staphylococci in 26.4% (23/87). While vancomycin was active against all Gram-positive isolates tested (100%), ceftazidime had the highest susceptibility rate (100%) for Gram-negative organisms isolated. Conclusions: Although coagulase-negative micrococci predominated in this series, a high isolation rate for Gram-negative organisms was obtained. High susceptibility rates for ofloxacin make it an alternative to ceftazidime and vancomycin in both Gram-negative- and Gram-positive-derived endophthalmitis, respectively. Studies with larger series and additional antibiotics are needed to confirm these findings.
Intravascular Papillary Endothelial Hyperplasia – A Rare Finding in the Orbital Region
Authors: Schulze Stephan , Hoerle Steffen , Koop Gudrun , Barth Peter J. , Huegens-Penzel Monika , Strempel Ilse
Published: May 2008

Intravascular papillary endothelial hyperplasia is a benign lesion of vascular origin. It is caused by excessive proliferation of endothelial cells in vascular malformations or normal blood vessels. We report the case of a 58-year-old woman sent to our clinic for surgery of an orbital fat prolapse at her right eye. The clinical examination showed a displacable swelling with a slightly livid aspect approximately 2 cm in diameter under the upper orbital rim. After MRI, a biopsy was carried out leading to the histological diagnosis of intravascular papillary endothelial hyperplasia. The complete excision of the remaining tumor was performed 8 weeks later. We discuss this clinical entity and the management of such lesions in the orbital region.
Chemotherapy with Gemcitabine and Oxaliplatin in Patients with Advanced Biliary Tract Cancer: A Single-Institution Experience
Authors: Manzione Luigi , Romano Rosangela , Germano Domenico
Published: May 2008

Background: Biliary tract cancers are uncommon tumors with a poor prognosis. Since most patients present with invasive and inoperable disease at diagnosis, treatment consists of palliative chemotherapy, with poor response rates and a median survival of less than 6 months. Oxaliplatin and gemcitabine have shown interesting activity as single agents in this patient group. Objective: A single-institution phase II study was performed to evaluate the efficacy and safety of combination therapy with oxaliplatin and gemcitabine in locally advanced and metastatic biliary tract carcinomas. Patients and Methods: Combination chemotherapy consisted of gemcitabine 1,000 mg/m2 on day 1 and oxaliplatin 100 mg/m2 on day 2 every 2 weeks. Treatment was administered until disease progression, unacceptable toxicity or patient refusal. Thirty-five consecutive patients with advanced biliary tract carcinoma, aged 18–80 years, with Eastern Cooperative Oncology Group performance status ≤2 were entered into our study from November 2003. Results: Thirty- four patients were evaluable for response and toxicity. According to RECIST criteria, 2 patients had a complete response and 12 had a partial response, with an overall response rate of 41%. Overall survival in our patients was 10 months (range 2–30). According to WHO criteria, 3 patients (9%) suffered from grade 3 neutropenia and 7 patients (21%) from grade 3 thrombocytopenia. Only 3 patients (9%) had grade 3 neuropathy. Conclusions: The GEMOX combination seems to be active with a favorable safety profile in first-line chemotherapy of advanced biliary tract cancers.
General Preadaptation of Viral Infectors to Their Hosts
Authors: Barrai I. , Salvatorelli G. , Mamolini E. , De Lorenzi S. , Carrieri A. , Rodriguez-Larralde A. , Scapoli C.
Published: May 2008

We tested the hypothesis of optimal adaptation of viral infectors to eukaryotic hosts, using (1) correlation in codon and amino acid usage between organisms, and (2) canonical correlation between groups of hosts and infectors. The codon correlations between parasites and hosts vary, being low between swine and African swine fever virus (ASF; r = 0.18), and highest between potato and potato virus X (r = 0.60). The correlations might indicate different stages of evolution toward optimal adaptation of the parasite codon distribution to the host tRNA pools. The amino acid correlations vary from r = 0.71 between pig and ASF, to 0.88 between catfish and its herpesvirus. It was observed that both in virus and hosts, there is a negative correlation between frequency of an amino acid and molecular weight. Therefore, it was advanced that viral infectors might be preadapted to their hosts because of similarities of the tRNA pools of hosts, and that evolution toward optimization would be dependent on the size of the divergence between the codon distributions of infector and host. Preadaptation does not imply origin of the virus by lateral transfer from the present host, since the correlation of the molecular weight of amino acids with their abundance in proteins is a general phenomenon.
Similar Cytokine Profiles in Response to Infection with Respiratory Syncytial Virus Type A and Type B in the Upper Respiratory Tract in Infants
Authors: Bermejo-Martin Jesus F. , Tenorio Alberto , Ortiz de Lejarazu Raul , Eiros Jose M. , Matías Vanesa , Dominguez-Gil Marta , Pino Maria , Alonso Ana , Blanco-Quiros Alfredo , Arranz Eduardo , Ardura Julio
Published: May 2008

Human respiratory syncytial virus (RSV) is the leading viral cause of severe respiratory illness in infants and young children worldwide. RSV isolates can be divided into 2 subgroups, type A and type B. Here, we compare for the first time the nasal profiles of 27 immune mediators in response to both viral subtypes in 14 children infected with RSV/A, 8 children infected with RSV/B, 11 children coinfected with RSV/A plus other respiratory viruses, and finally, 27 control children, all <2 years old. Our results evidence that children’s infection with both RSV subtypes induces very similar profiles of immune mediators in the upper respiratory tract, characterized by the elevation of Th1 and Th2 cytokines, chemokines and growth factors. Interestingly, no major differences in the profiles of the immune mediators were found between the children infected exclusively with RSV/A and those infected with RSV/A plus other respiratory viruses.
Analysis of ribosomal and alphoid repetitive DNA by fiber-FISH
Authors: Shiels C. , Coutelle C. , Huxley C.
Published: May 2008

We have used fluorescence in situ hybridization to extended DNA fibers (fiber-FISH) to analyse the α-satellite and rDNA arrays on a human chromosome 22. The rDNA could be seen as a string of signals spanning about 430 kb. The bulk of the alphoid DNA was found in a single large array of about 2.6 Mb.