bluuebunny/crossref_metadata_2025 huggingface dataset:
The ASME PSA Standard and Its Role in Risk Informed Regulation
Authors: Schneider Raymond E.
Published: October 2008

The nuclear industry has been aggressively pursuing risk-informed regulation for the past seven years. In this pursuit, the Nuclear Regulatory Commission (NRC) has established a basic framework for reviewing and granting risk-informed regulations. Focused regulatory guides have been specifically prepared in the areas of Plant Technical Specifications, In-Service Testing, In Service Inspections and Graded Quality Assurance. While these regulations have not supplanted traditional deterministic regulations, they have been used to support focused changes to the plant design basis. As the industry continues to mature the use of PSA information in day to day plant operations will grow. Today, risk insights are required by federal regulation for all plant maintenance activities. In addition, the regulator reserves the right to include consideration of risk in applications where the outcome could have a significant impact on risk. Despite, the major strides made in development and use of risk information, the industry and the regulator were operating without an agreed to PSA standard. Over the past three years the ASME has formed a committee of stakeholders, both commercial and regulatory, to develop a workable standard for the development and utilization of PSA data in the nuclear industry. The ASME PSA standard has recently been issued. The current standard has been developed to support licensing applications and is focused on the development and use of the Level 1PSA and the calculation of the Large Early Release Frequency (LERF). The ASME standard is unlike most standards in that it is tiers, and includes guidance for using results when specific items in the standard are not in complete compliance with specific standard elements. The tiers included in the standard are reflective of the level of detail in the PSA elements. The ability to use PSAs with many elements acceptable only at the lowest tier will be more limited than for more sophisticated PSAs and therefore, applications may be limited in scope and would likely involved strong deterministic support as well. As PSA tiers increase the reliance of the decision on the PSA may increase. The acceptability of the PSA elements is established via peer review process. It is the intent of this panel discussion to explore the implications of the recently released ASME PSA standard, and other focused standards under development on the nuclear industry and the role of the ASME standard in the associated regulatory process. The panelists will explore expectations of the industry, needs of the regulator and challenges of the PSA peer review process.
Effect of Strain Rate on Low Cycle Fatigue Behavior of Thermally Aged A533B Pressure Vessel Steels in High Temperature Water
Authors: Wu Xinqiang , Katada Yasuyuki
Published: October 2008

Safe and reliable management of light water reactors demand a full understanding on their component materials properties throughout their service lives. In present work the effects of strain rate on low cycle fatigue behavior of ASTM A533B pressure vessel steels after long-term thermal aging at 673 K in air have been investigated in simulated BWR environments. It was found that the aging treatment led to a certain decrease in fatigue life. Environmental effect on the fatigue life of aged materials closely depended on strain rate. More strongly environmental effect appeared at low strain rate. The aging treatment enhanced the stain-rate dependence of the fatigue resistance of A533B steels. Comparison between ASME design fatigue curves and present results as well as some literatures’ data suggested that safety margins of the standard design curves tended to decrease with decrease in strain rate. Based on the above results, possible corrosion fatigue mechanisms of pressure vessel steels in high temperature water were discussed by taking into account the effects of inclusions, hydrogen embrittlement, dynamic strain aging and aging-induced material degradation as well as their combined actions.
Section III and Section XI: Integration in the Design Specification and Design Report
Authors: Land John T.
Published: October 2008

One of the activities of power plant owner’s and equipment providers today is upgrading and/or repair/replacement of original equipment. Plant life extension, and fatigue evaluation are also activities that are being performed routinely. These activities come under the rules and guidance of the ASME Boiler and Pressure Vessel Code, Section XI, whereas, the original equipment generally came under the rules of Section III.
Analysis of Fluid-Elastic Instability for KSNP Steam Generator Tube and Its Plugging Effect at Central Region
Authors: Ryu Ki-Wahn , Cho Bong-Ho , Park Chi-Yong , Park Su-Ki
Published: October 2008

The characteristics of fluid-elastic instability for the KSNP steam generator tubes were investigated numerically. The information on the thermal-hydraulic data of the steam generator has been obtained by using the ATHOS3-MOD1 code and the fluid-elastic instability analysis has been conducted by using the PIAT (Program for Integrity Assessment of Steam Generator Tube) code. The KSNP steam generator has the concentrated plugging zone at the vicinity of the stay cylinder inside the steam generator. To investigate the cause of the concentrated plugging, the fluid-elastic instability analysis has been performed on various column and row number of the KSNP steam generator tubes. From the results of this study the stability ratio due to the fluid-elastic instability in the concentrated plugged zone tend to have larger values than those of the outer zone. Even though the further study will still be required, these results seem to be related with concentrated plugging inside the steam generator. And the stability ratio of plugged tube does not have any consistent advantages for all modes over the normal one. This seems to be caused by the decrease of mass, the increase of natural frequency, and the change of mode shape after plugging.
Discussion on Two Times Integral Displacements of Strong Ground Motion Records and Shaking Table Data
Authors: Toyoshima Manabu , Minowa Chikahiro
Published: October 2008

In this paper, two times integral of acceleration record was discussed by the use of strong earthquake motion data; recorded in the 1999 Kocaeli (Turkey) Earthquake data. Usually, the two times integral displacements of horizontal seismic acceleration records will diverge. It was estimated for the integral displacement to diverge by the baseline shift caused on sensor tilting during quake. The data was simulated in 3 dimensional and 6 freedom shaking table. The divergent process of seismic data and shaking table data were studied.
Stress Intensity Factors for a Curved-Front Internal Crack in an Autofrettaged Tube With Bauschinger Effect
Authors: Tan Choon-Lai , Parker Anthony P. , Cassell Chantz W. V.
Published: October 2008

Pressure vessel steels exhibit the Bauschinger effect that significantly reduces post-autofrettage residual compressive hoop stresses in the near-bore region in comparison with ‘ideal’ (elastic-perfectly plastic) behavior. These reduced hoop stress profiles were calculated using Von Mises’ criterion via a non-linear analysis for the case of open-end (engineering plane strain) autofrettage. These profiles were then used to obtain stress intensity factor solutions via the Boundary Integral Equation (BIE) method, commonly known as the Boundary Element Method (BEM). Results are presented for tubes of diameter ratio 2 and 2.5 with an internal semi-elliptical surface crack having a maximum depth/surface length ratio of 0.4 (i.e. an eccentricity of 0.8). Crack depths range from 20% to 80% of wall thickness and results are presented for seven locations on the crack front from maximum depth to free surface. For crack depths up to 20% of wall thickness there is a significant reduction in magnitude of autofrettage stress intensity factor due to Bauschinger effect. For typical overstrain levels this reduction is approximately 30% of ‘ideal’ values. Such a reduction may, in turn, cause an order of magnitude reduction in the fatigue lifetime of the vessel.
Pipeline Girth Weld Inspections Using Ultrasonic Phased Arrays
Authors: Moles Michael , Dube´ Noe¨l , Ginzel Ed
Published: October 2008

Automated ultrasonics is rapidly replacing radiography worldwide for gas pipeline girth weld inspections. Compared with radiography, mechanized ultrasonics is more reliable, faster, has better detection of critical Lack of Fusion defects, and poses no safety hazard. Phased arrays are the latest development in AUT, and present major improvements over conventional ultrasonics. Probe pans are lighter and smaller; scans are quicker due to the smaller probe pan; phased arrays are considerably more flexible for changes in pipe dimensions or weld profiles, and for different scan patterns for unusual defects; special scans can be made for specific problems. This paper describes the PipeWIZARD ultrasonic phased array system for girth weld inspections, based on the ASTM E-1961 code and compatible with API 1104 19th Edition. Some comments on AUT codes will be made. The paper will describe the latest phased array UT results, plus developments like automated set-ups and improved imaging using an increased number of zones. PipeWIZARD’s track record and capabilities will be illustrated.
The effect of group-based exercise on cognitive performance and mood in seniors residing in intermediate care and self-care retirement facilities: a randomised controlled trial
Authors: Brown A K , Liu-Ambrose T , Tate R , Lord S R
Published: October 2008

Objective:

To determine the effect of a general group-based exercise programme on cognitive performance and mood among seniors without dementia living in retirement villages.

Design:

Randomised controlled trial.

Setting:

Four intermediate care and four self-care retirement village sites in Sydney, Australia.

Participants:

154 seniors (19 men, 135 women; age range 62 to 95 years), who were residents of intermediate care and self-care retirement facilities.

Intervention:

Participants were randomised to one of three experimental groups: (1) a general group-based exercise (GE) programme composed of resistance training and balance training exercises; (2) a flexibility exercise and relaxation technique (FR) programme; or (3) no-exercise control (NEC). The intervention groups (GE and FR) participated in 1-hour exercise classes twice a week for a total period of 6 months.

Main outcome measures:

Using standard neuropsychological tests, we assessed cognitive performance at baseline and at 6-month re-test in three domains: (1) fluid intelligence; (2) visual, verbal and working memory; and (3) executive functioning. We also assessed mood using the Geriatric Depression Scale (GDS) and the Positive and Negative Affect Schedule (PANAS).

Results:

The GE programme significantly improved cognitive performance of fluid intelligence compared with FR or NEC. There were also significant improvements in the positive PANAS scale within both the GE and FR groups and an indication that the two exercise programmes reduced depression in those with initially high GDS scores.

Conclusions:

Our GE programme significantly improved cognitive performance of fluid intelligence in seniors residing in retirement villages compared with our FR programme and the NEC group. Furthermore, both group-based exercise programmes were beneficial for certain aspects of mood within the 6-month intervention period.
Hydraulic Investigation of a Unique Proposal for the Carrot River Bridge Crossing
Authors: Smith Cliff D.
Published: October 2008

This paper gives details of the hydraulic investigation carried out for the proposed new bridge crossing over the Carrot River on Highway No. 23, near Carrot River, Saskatchewan. Geotechnical studies indicated that due to the very low shear strength of the highly plastic clay comprising the banks of the Carrot River, the river banks would not be capable of supporting the approach fills to the bridge. Highways Department engineers came up with the rather novel idea of placing a compacted clay fill or berm across the river at the bridge site in order to stabilize the banks. This introduced the problem of passing river flows through and over the berm. It was proposed that low flows should be carried through the berm by a culvert, and high flows should be passed over the berm by a spillway. Hence, the design envisaged a bridge over an earth fill and a spillway over a culvert, all at one site. A model study was considered essential because of the uncertain hydraulics and because a hydraulic failure could result in bridge failure.
Shear and Overturning Moment for Earthquake-resistant Building Design
Authors: Humar J. L. , Wright E. W.
Published: October 2008

The provisions of the present Canadian and U.S. seismic codes are examined with respect to their requirements on the distribution of seismic forces and overturning moments throughout the heights of building structures. Assuming the code design base shears to be correct, it is shown that the prescribed distribution of lateral forces may underestimate the shear forces in the upper stories of the building. It is further shown that the contribution of the higher modes is not directly related to the height-to-width ratio of the building, but rather to its fundamental period of vibration. By idealizing the building as an average uniform cantilever deflecting partly in a shear mode and partly in a bending mode and by taking a root-sum-square combination of the modal responses to a standard seismic acceleration spectrum, the envelope of the resultant maximum shears throughout the building height is obtained; the maximum overturning moments throughout the building height are obtained in a similar manner. By comparing these with the cantilever overturning moments computed from the shear envelope referred to above, the moment reduction factors applicable to the various levels of a building are calculated. New empirical relationships are then developed to approximate the shape of the maximum shear and overturning moment envelopes.
Planning defences against avalanches
Authors: Schaerer P. A.
Published: October 2008

Protective measures against snow avalanches must be effective, practical, and as economical as possible. The information concerning the objectives of an avalanche defence, the terrain, and the characteristics of the avalanches, required for the design of the defence system, is outlined. A discussion is presented of the economical and operational factors that must be considered in the analyses of alternative defences and in choosing the optimum method.
Observations on break-up of river ice in north central Alberta
Authors: Nuttall J. B.
Published: October 2008

The break-up process on the North Saskatchewan and Pembina Rivers in north central Alberta during 1969 is discussed.It is shown that the maximum size of moving ice can approach the river's width and have a length of four or five times this depending upon channel geometry. A case of radial cracking of an ice sheet at a bridge pier when the sheet was subject to the drag force of high velocity river flow is reported. The rate of progress of a break-up wave on the Pembina River was found to have been approximately that of a free surface water wave of the same height.
Pile tests at Beech River
Authors: Selby K. G.
Published: October 2008

A program of pile loading tests has been carried out by the D.H.O. Foundation Section, at the site of the proposed new bridge over Beech River on Hwy. 35 near Carnarvon, Ontario. Subsoil consists of deep deposits of sands and silts. Five piles of various lengths were tested to failure, these being [Formula: see text]. O.D. (32.4 cm) steel tubes, 12 BP 53 steel H-piles, and one No. 14 timber pile.The results of the tests have been compared with predictions based on theoretical and empirical conventional methods and, also, by a method using information obtained in the field using the Geoprobe. The results of the load tests illustrate clearly the difficulties involved in attempting to assess loading capacities of piles in cohesionless soils by means of the conventional methods based on soil properties determined during routine foundation investigations.
AN INTEGRATED GAME-THEORY BASED MODEL FOR TRANS-BOUNDARY WATER RESOURCES MANAGEMENT IN NORTH CHINA: A CASE STUDY IN THE GUANTING RESERVOIR BASIN (GRB), BEIJING
Authors: YANG ZHIFENG , ZENG YONG , CAI YANPENG , TAN QIAN
Published: October 2008

Water is a fundamental resource in our daily lives and for social development. Currently, water resources are under stressed conditions in north China due to the ongoing growth of demand for water and the frequent occurrences of natural disasters in this area. This problem is further intensified by the deterioration of water quality, which is a side effect of economic development, industrial expansion, and agricultural growth. These problems interconnect with each other, leading to a variety of conflicts over water resources. To resolve such conflicts, a two-person game-theory based model is developed for water resource management in the trans-boundary regions of a river basin. The model is tested on a river basin within this area of China in which water resources are contested. Through the developed model, potential policy alternatives can be generated for water resource management and pollution control within the context of a river basin. Cooperative and/or competitive mechanisms can thus be formulated through competition and cooperation over issues of water quantity and quality among different levels of jurisdictions in the same river basin. Then, Nash Solution is used to solve scenarios of competition and cooperation between the upstream and downstream based on the integration of optimization and simulation models. The developed model and the solution process is then applied to resolve water conflicts between Beijing and Hebei province, which are in the upstream and downstream of the Guanting Reservoir Basin (GRB), respectively, representing two major stakeholders in the contest over water quantity and quality. Non-cooperative and cooperative scenarios for the two-player game scenarios are developed to investigate and compare potential economic benefits of these scenarios. Results indicate that the developed model can be effectively and flexibly employed to resolve water conflicts between upstream and downstream stakeholders in the same river basin. The results can also be used to help formulate economic compensation mechanisms within these jurisdictions.
Stratigraphy and sedimentology of the Permian of the Falkland Islands: lithostratigraphic and palaeoenvironmental links with South Africa
Authors: TREWIN N. H. , MACDONALD D. I. M. , THOMAS C. G. C.
Published: October 2008

Comparison of the facies, ichnology and palaeocurrent patterns of the Permian of the Falkland Islands and the Dwyka, Ecca and Beaufort (part) groups in South Africa supports the hypothesis that the Falkland Islands lay east of South Africa in a rotated position prior to continental break-up. Key sections in the Falklands (NW Lafonia) and the Eastern Cape (Ecca Pass) would have lain about 200 km apart in Permian time. In the absence of accurate chonostratigraphic and biostratigraphic information from the Permian of the Falkland Islands, emphasis is placed on lithostratigraphic comparison. The Permian successions in both areas pass from diamictite through basin floor sediments, including organic-rich shale, rhythmites and turbidites. Mud-dominated delta front deposits culminating in channel deposits of a generally subaqueous delta top overlie the basin floor sediments. Points of close lithostratigraphic comparison are: (1) the diamictites have identical appearance, facies, and compatible palaeocurrents; (2) glacial sections are overlain by organic-rich black shales; (3) K-bentonites occur in basin-floor successions; (4) presence of basin-floor turbidite sandstone units with interbedded rhythmite units, and a distinctive
Umfolozia/Undichna
ichnofauna; (5) coarsening-up delta-front sequences are overlain by fining-up channel sandstone facies; (6) there is a close petrographic similarity indicating derivation of sandstones from a contemporaneous volcanic arc.

The Permian successions of the two areas form parts of the fill of the eastern end of the main Karoo Basin, and were subject to the same influences of tectonic development, sediment derivation, eustatic variation and climatic change.
Tectonic setting of primitive magmas in volcanic arcs: an example from the Antarctic Peninsula
Authors: LEAT P. T. , RILEY T. R. , WAREHAM C. D. , MILLAR I. L , KELLEY S. P. , STOREY B. C.
Published: October 2008

Abstract:
Primitive magmas representing mantle partial melts minimally affected by fractionation and assimilation are rare in the magmatic arc environment. Most examples are either associated with high rates of arc-parallel extension, or occur along faults and dykes perpendicular to the trend of the arc and related to arc compression. In two cases, the Vanuatu and Solomon Islands arcs, such arc compression is being caused by collision of seamounts. In the Antarctic Peninsula, primitive mafic dykes were emplaced perpendicular to the continental arc. Ar–Ar and K–Ar data suggest intrusion of the dykes at
c.
126–106 Ma, possibly during mid-Cretaceous regional compression of the arc. The dykes form two compositional groups. One group has low La
N
/Yb
N
ratios (0.31–0.49), lower Nb/Yb and higher Th/Nb than N-MORB, age-corrected ϵNd values of +7.3 to +7.9, and are interpreted as melts of subduction modified sub-arc asthenosphere. The other has high La
N
/Yb
N
ratios (3.86–8.92), higher Nb/Yb and Th/Nb than N-MORB, age-corrected ϵNd values of −2.8 to +3.4, and are interpreted as melts of sub-arc lithosphere. The absence of dykes compositionally between these groups suggests that the primitive magmas avoided storage and mixing in magma chambers.
Dating the Late Precambrian volcanicity of England and Wales
Authors: COMPSTON W. , WRIGHT A. E. , TOGHILL P.
Published: October 2008

Abstract:
Ages for volcanism in the British Late Precambrian have been inferred from interpretations of SHRIMP zircon ages as follows: 559.3 ± 2.0 Ma for a tuff from the Beacon Hill Formation of the Charnian Supergroup; 566 ± 3 Ma for a tuff at Bardon Hill also in the Charnwood Forest area with abundant inherited grains at 590.5 ± 1.6; 566.6 ± 2.9 Ma and 555.9 ± 3.5 Ma for bentonite and tuff in the Stretton Group of the Longmyndian Supergroup; 604.7 ± 1.6 Ma for an ignimbrite of the Padarn Tuff Formation of the Arfon Group, and 572.5 ± 1.2 Ma for a tuff within the Fachwen Formation of the Arfon Group. These ages confirm that there were two major phases of volcanic activity in the English Midlands and Wales, one about 620–590 Ma and another about 575–550 Ma. This was followed in most of England and Wales by a major phase of tectonism before the Cambrian (Tommotian) transgression across the Midland Platform. Within the depocentre of the Welsh early Palaeozoic basin, however, sedimentation started within the second period of volcanism and may have continued without interruption well into the Cambrian Period. It is probable that the late phases of the Avalonian Orogeny lasted until after the beginning of the Cambrian. These new data show that the terranes of the Avalonian of England and Wales are comparable with those of eastern Canada and New England. The age estimate for the
Charnia
horizon is broadly similar to those obtained elsewhere in the world on rocks containing the earliest Ediacaran fauna and adds to the building of an extended time-scale for the global Ediacaran.
Basement chronology of the Antarctic Peninsula: recurrent magmatism and anatexis in the Palaeozoic Gondwana Margin
Authors: MILLAR I. L. , PANKHURST R. J. , FANNING C. M.
Published: October 2008

Abstract:
A revised pre-Jurassic chronology is presented for the Antarctic Peninsula on the basis of new U–Pb zircon dating, using both conventional (11 samples) and SHRIMP microprobe data (10 samples). The age range for plutonism and high-grade metamorphism is from 435 ± 8 Ma (Silurian) to
c.
206 Ma (approximately the Triassic–Jurassic boundary), with peaks of activity in Devonian, Carboniferous, Permian and mid-Triassic times, although some are represented by rocks with limited outcrops. The new data confirm the importance of Mid- and latest Triassic magmatic events, previously identified using Rb–Sr geochronology. The Adie Inlet gneiss, previously thought to be Neoproterozoic, is recognized as a Permian migmatite derived from paragneiss with a provenance dominated by Cambrian granitoids. Granite gneiss from NW Palmer Land, previously dated as Cambrian, is shown to be Triassic. Detrital zircons in metasedimentary rocks, and inherited zircons in granitoids, are dominated by Mesoproterozoic to Cambrian components, with sparse Palaeoproterozoic to Archaean grains, suggesting sources within Gondwana. At times these sources were nearby, as shown by an Archaean cobble-sized granite clast from a Permo-Triassic conglomerate; another clast in the same conglomerate, previously thought to be Devonian in age, has an Ordovician crystallization age.
Mid-Triassic integrated U–Pb geochronology and ammonoid biochronology from the Balaton Highland (Hungary)
Authors: PÁlfy JÓzsef , Parrish Randall R. , David Karine , VÖrÖs Attila
Published: October 2008

Ladinian (Middle Triassic) strata of the Balaton Highland (west–central Hungary) comprise interbedded marine carbonate and volcaniclastic rocks. The sediments are noted for their rich ammonoid faunas, which allow detailed biostratigraphic subdivision and correlation. For the first time, isotopic dating of the tuff layers was carried out to calibrate the age of ammonoid zones and subzones. Four successive horizons were dated from the Felsouu"örs section, a candidate stratotype for the base of the Ladinian stage. Within the Reitzi Zone, which is interpreted here as the basal Ladinian unit, the following biostratigraphically tightly constrained U–Pb zircon ages were obtained: Felsoeoersensis Subzone 241.1 ± 0.5 Ma; Liepoldti Subzone 241.2 ± 0.4 Ma; Reitzi Subzone 240.5 ± 0.5 and 240.4 ± 0.4 Ma. A redeposited tuff from the Gredleri Zone at Litér yielded an additional U–Pb age of 238.7 ± 0.6 Ma. The new isotopic ages are in agreement with published U–Pb dates from the Southern Alps. Together, they allow estimation of the start of the Ladinian at 241.5 Ma and of the end of the stage at 237 Ma. A duration of <5 Ma for the stage strengthens the argument that cyclicity of the Ladinian Latemar platform (Southern Alps) is not exclusively of Milankovitch origin but forcing with shorter, sub-Milankovitch periods was also involved. The Ladinian, which started 10 Ma after the latest-Permian mass extinction, was a time of radiation and rapid evolutionary turnover, hence empirically established ammonoid biozones are of short duration, averaging 0.75 Ma.
Reconstructing the Siluro-Devonian coastline of Gondwana: insights from the sedimentology of the Port Stephens Formation, Falkland Islands
Authors: Hunter M.A. , Lomas S.A.
Published: October 2008

Silurian and lower Devonian sedimentary successions are uncommon within the remnants of Gondwana. The Port Stephens Formation, the basal unit of the middle Palaeozoic West Falkland Group, presents a rare opportunity to study Gondwanan material of Siluro-Devonian age. The formation on West Falkland is
c
. 2560 m thick and consists of five members: Plantation, Albemarle, Mount Alice, South Harbour and Fish Creek. Thirty-five lithofacies are defined using variations in grain size and bedding characteristics. The distribution of these lithofacies and their associated ichnofacies between the various members lead us to suggest terrestrial and shallow marine deposition on an extensive, gently shelving alluvial to coastal plain. Vertical facies trends through the Port Stephens Formation, and into the base of the overlying Fox Bay Formation, record a complex superposition of subenvironments within a distinct overall transgressive–regressive–transgressive pattern, with the bulk of sediment accumulating during the regressive phase. Palaeocurrents indicate a basin to the present-day NE throughout. These results, together with lithostratigraphic correlations between the Port Stephens Formation and the Nardouw Subgroup in South Africa, are consistent with a reconstructed position off eastern South Africa and on the palaeo-Pacific margin of Gondwana, requiring a near-180° rotation of the Falkland Island microplate during break-up, in agreement with previous models. We suggest that global changes in sea level during the mid–late Silurian and early Devonian strongly influenced changes in the depositional environment. Enhanced erosion of the continental margin and extensive sediment bypass during the regressive phase of this cycle could help to explain the low abundance of preserved Gondwanan material of this age.
Oceanic gateways as a critical factor to initiate icehouse Earth
Authors: SMITH ALAN G. , PICKERING KEVIN T.
Published: October 2008

We propose a unifying explanation for the four major icehouses during the past
c.
620 million years: earliest Oligocene to Present; early Carboniferous to early Permian; late Ordovician and late Vendian (the ‘snowball Earth’) all of which appear to have been initiated as a result of two plate-tectonic processes. The first moved some continents into polar latitudes; while there the second process opened and closed oceanic low latitude gateways that changed global oceanic circulation from one with important circum-equatorial currents (greenhouse) to one with inhibited circum-equatorial deep-water currents (icehouse) and more restricted oceanic gyres.
Dewetting and Hydrophobic Interaction in Physical and Biological Systems
Authors: Berne Bruce J. , Weeks John D. , Zhou Ruhong
Published: October 2008

Hydrophobicity manifests itself differently on large and small length scales. This review focuses on large-length-scale hydrophobicity, particularly on dewetting at single hydrophobic surfaces and drying in regions bounded on two or more sides by hydrophobic surfaces. We review applicable theories, simulations, and experiments pertaining to large-scale hydrophobicity in physical and biomolecular systems and clarify some of the critical issues pertaining to this subject. Given space constraints, we cannot review all the significant and interesting work in this active field.
Activation of the Epithelial Sodium Channel (ENaC) by Serine Proteases
Authors: Rossier Bernard C. , Stutts M. Jackson
Published: October 2008

The study of human monogenic diseases [pseudohypoaldosteronism type 1 (PHA-1) and Liddle's syndrome] as well as mouse models mimicking the salt-losing syndrome (PHA-1) or salt-sensitive hypertension (Liddle's syndrome) have established the epithelial sodium channel ENaC as a limiting factor in vivo in the control of ionic composition of the extracellular fluid, regulation of blood volume and blood pressure, lung alveolar clearance, and airway mucociliary clearance. In this review, we discuss more specifically the activation of ENaC by serine proteases. Recent in vitro and in vivo experiments indicate that membrane-bound serine proteases are of critical importance in the activation of ENaC in different organs, such as the kidney, the lung, or the cochlea. Progress in understanding the basic mechanism of proteolytic activation of ENaC is accelerating, but uncertainty about the most fundamental aspects persists, leaving numerous still-unanswered questions.
Assessment of heterogeneous airway constriction in dogs: a structure-function analysis
Authors: Kaczka David W. , Brown Robert H. , Mitzner Wayne
Published: October 2008

Obstructive lung diseases are often characterized by heterogeneous patterns of bronchoconstriction, although specific relationships between structural heterogeneity and lung function have yet to be established. We measured respiratory input impedance (Zrs) in eight anesthetized dogs using broadband forced oscillations at baseline and during intravenous methacholine (MCh) infusion. We also obtained high-resolution computed tomographic (HRCT) scans in 4 dogs and identified 20–30 individual airway segments in each animal. The Zrs spectra and HRCT images were obtained before and 5 min following a deep inspiration (DI) to 35 cmH2O. Each Zrs spectrum was fitted with two different models of the respiratory system: 1) a lumped airways model consisting of a single airway compartment, and 2) a distributed airways model incorporating a continuous distribution of airway resistances. For the latter, we found that the mean level and spread of airway resistances increased with MCh dose. Whereas a DI had no effect on average airway resistance during MCh infusion, it did increase the level of airway heterogeneity. At baseline and low-to-moderate doses of MCh, the lumped airways model was statistically more appropriate to describe Zrs in the majority of dogs. At the highest doses of MCh, the distributed airways model provided a superior fit in half of the dogs. There was a significant correlation between heterogeneity assessed with inverse modeling and the standard deviation of airway diameters obtained from HRCT. These data demonstrate that increases in airway heterogeneity as assessed with forced oscillations and inverse modeling can be linked to specific structural alterations in airway diameters.
Reference Values of Semen Parameters for Healthy Chinese Men
Authors: Gao Jun , Gao Er Sheng , Walker Mark , Yang Qiuying , Wu Jun Qing , Zhu Quan Xi , Wen Shi Wu
Published: October 2008

Aims: To establish reference values of semen parameters in a residential, geographic, and age representative sample of healthy Chinese men. Methods: From a national study of 1,191 healthy Chinese men, semen samples were analyzed from 105 subjects whose wives or partners were pregnant within the 12 months prior to the date when the semen sample was taken. Results: The means, fifth percentiles, and percentages lower than the WHO criteria for semen parameters were, respectively: 75.8 × 106/ml, 17.8 × 106/ml, and 6.7% for sperm concentration; 206.9 × 106/ejection, 26.3 × 106/ejection, and 6.7% for total sperm count; 18.9, 3.0, and 79.1% for rapid progressive motility; 49.1, 25.3, and 52.4% for sperm progressive motility; 73.8, 49.3, and 45.7% for sperm viability, and 49.5, 25.2, and 9.5% for normal morphology. Conclusion: The values of semen parameters for Chinese men are lower than the WHO criteria, especially for rapid progressive motility, progressive motility, and sperm viability, and a different standard for Chinese may be needed.
Effect of Naloxone on Oxidative Stress and Testicular Injury due to Spermatic Vessel Ligation of Rat Testis
Authors: Cakan Murat , Yilmazer Demet , Cakan Turkay , Aydos Tolga R. , Ogus Elmas , Kilinc Aytun S. , Hücmenoglu Sema , Altug Ugur
Published: October 2008

Aims: Two-stage Fowler-Stephens orchiopexy has been accompanied by testicular atrophy in some cases but neither of the mechanisms responsible for testicular injury are clear, nor is there an effective agent that might prevent this injury. In this study we aimed to investigate the long-term effects of naloxone, a morphine antagonist, on testicular histopathology and oxidative stress after spermatic vessel ligation (SVL) in rats. Methods: 32 prepubertal rats were randomly divided into four equal groups: group 1: control (only bilateral orchiectomies were performed); group 2: sham-operated group; group 3: SVL, and group 4: SVL+naloxone (1 mg/kg twice daily for 1 month). One month postoperatively, bilateral orchiectomies were performed to evaluate histopathologic findings and measurement of malondialdehyde (MDA) and nitric oxide (NO) levels. Results: Considering group 3, left SVL resulted in significant tissue damage in both testes, more severe in the ipsilateral testis. The SVL resulted in a significant increase in testicular MDA levels of both testes in this group (p < 0.05). While the ipsilateral testicular NO levels of groups 2 and 3 were significantly lower than of group 1 (p < 0.05), the contralateral testicular NO levels of all these groups were similar. After naloxone therapy, while there was no significant improvement in ipsilateral testicular histopathology (p > 0.05), the contralateral testicular histopathology improved significantly (p < 0.05). However, naloxone did not change either testicular MDA or NO levels. Conclusions: The SVL led to bilateral testicular injury, and oxidative stress may be a reason for this injury. Naloxone significantly improved contralateral testicular injury without showing any antioxidative effect.
Preliminary Experimental Study of Tissue-Engineered Urethral Reconstruction Using Oral Keratinocytes Seeded on BAMG
Authors: Li Chao , Xu Yuemin , Song Lujie , Fu Qiang , Cui Lei , Yin Shuo
Published: October 2008

Introduction: This study investigates the feasibility of replacing urinary epithelial cells with oral keratinocytes seeded on a bladder acellular matrix graft (BAMG) to reconstruct a tissue-engineered urethra. Materials and Methods: After enzymatic treatment of a small segment of rabbit buccal mucosa (1.0 × 0.4 cm), the epidermis and dermis were separated mechanically. Oral keratinocytes were isolated from the epidermis and seeded onto a culture dish with a feeder layer of 3T3 mouse fibroblasts inhibited by mitomycin (i3T3) or on a culture dish without i3T3, respectively. These cells were expanded and applied to sterilized BAMG to obtain a tissue-engineered mucosa. Oral keratinocytes were assessed by growth curve, morphology and immunofluorescence staining. The tissue-engineered mucosa was assessed using morphology, immunohistochemistry staining and scanning electron microscopy. Results: Oral keratinocytes seeded onto a feeder layer of i3T3 had finer morphous and better amplification capability, and could be passaged for 8 generations. Oral keratinocytes that were cultured without i3T3 could only be subcultured 2 generations before ageing. Passage 2 oral keratinocytes cultured with i3T3 were expanded and seeded onto sterilized BAMG to obtain a tissue-engineered mucosa for urethral reconstruction. The compound graft was assessed using HE staining and scanning electron microscopy. Oral keratinocytes had good compatibility with BAMG. Conclusions: Rabbit oral keratinocytes of can be cultured in vitro and attain magnitude in quantity. Oral keratinocytes also had good compatibility with BAMG and the compound graft achieved could become a new choice in urethral reconstruction.
E-Cadherin Tissue Expression and Urinary Soluble Forms of E-Cadherin in Patients with Bladder Transitional Cell Carcinoma
Authors: Shi Benkang , Laudon Vincent , Yu Shengqiang , Dong Dexin , Zhu Yaofeng , Xu Zhishun
Published: October 2008

Objective: To investigate the clinical significance of E-cadherin (E-CD) expression in human bladder transitional cell carcinoma (TCC) tissue and soluble forms of E-cadherin (sE-CD) in the urine of patients with TCC. Materials and Methods: One hundred and two specimens of bladder TCC and 10 normal bladder tissues were stained immunohistochemically with anti-E-CD monoclonal antibody. The urinary sE-CD from 59 subjects with TCC or controls was measured with enzyme-linked immunosorbent assay (ELISA). All results were analyzed statistically between groups. Results: The expression of E-CD in bladder TCC correlated well with grade and stage but had no significant correlation with the size or number of the tumors. Normal expression rate of E-CD is significantly higher in primary than in recurrent tumors. The level of urinary sE-CD was higher in patients with TCC than in normal controls or patients with benign disorders of the urinary system. Urinary sE-CD levels were strongly correlated with tumor grade but showed no significant correlation with the stage, size and number of the tumors. The urinary sE-CD level is significantly higher in the recurrent group than in the primary group. Conclusions: Expression of E-CD in the tissue of TCC and the urinary level of sE-CD are very closely associated with the biological behaviors of bladder TCC.
Are New-Generation Bisphosphonates Effective for the Inhibition of Calcium Oxalate Stone Formation in a Rat Model?
Authors: Basok Erem Kaan , Basaran Adnan , Atsu Necmettin , Yildirim Asif , Tokuc Resit
Published: October 2008

Background: The effects of bisphosphonates on prophylaxis of stone formation are unclear. We evaluated the outcome of two new-generation bisphosphonates in a lithogenic rat model. Methods: 36 male rats were divided into three groups of 12 animals each. Both calcium and creatinine levels of plasma and urine were measured. Zinc discs of about 40 mg each were surgically placed into the bladder. The first group received no treatment and the second and third groups were treated with an intraperitoneal injection of weekly clodronate (20 mg/kg) and zoledronic acid (7.5 µg/kg), respectively. At the end of the 8th week, the weight increase in discs and biochemical changes were analyzed comparatively. Results: The mean weight of discs in the control, clodronate and zoledronic acid groups was 109.65 ± 80.97, 79.82 ± 17.99 and 72.91 ± 19.29 mg, respectively (p > 0.05). The percentage increase in weight of discs was 164% for control, 90% for clodronate and 71% for the zoledronic acid group. The increase of urinary calcium level in the zoledronic acid group was lower than the others (p < 0.05). Conclusions:When considering the percentage increase in weight of discs, the difference between control and bisphosphonate groups support the idea that these drugs may have a preventive role in stone formation.
Effects of Milnacipran and Paroxetine on Overactive Bladder due to Neurologic Diseases: A Urodynamic Assessment
Authors: Sakakibara Ryuji , Ito Takashi , Uchiyama Tomoyuki , Awa Yusuke , Yamaguchi Chiharu , Hattori Takamichi
Published: October 2008

Aims: To determine the effects of milnacipran hydrochloride, a serotonin-norepinephrine reuptake inhibitor (SNRI), or paroxetine hydrochloride, a selective serotonin reuptake inhibitor, on overactive bladder (OAB) in neurologic diseases, given by objective measures of urodynamic studies. Methods: This is a prospective open trial, and we enrolled 24 patients (16 men, 8 women; mean age, 63.9 years) with OAB in a neurology clinic. They were randomly allocated into two groups: the milnacipran group (11 patients), and paroxetine group (13 patients). We started with 100 mg/day of milnacipran or 40 mg/day of paroxetine. Before and 3 months after the treatment, we performed a urinary questionnaire and urodynamic studies. Results: Milnacipran reduced daytime urinary frequency (average, from 9.4 to 7.1 times, p < 0.001), improved the quality of life index (p = 0.023), and increased bladder capacity (average, from 289 to 377 ml, p = 0.009) as shown in urodynamic studies. No such changes were noted in the other categories of the lower urinary tract symptoms questionnaire or urodynamic studies, or in the paroxetine group. One male patient complained of mild voiding difficulty. Other adverse effects were not seen during the observation period. Conclusion: Milnacipran, an SNRI, increased bladder capacity as shown in urodynamic studies, and thereby ameliorated OAB in patients with neurologic diseases without serious adverse effects.
L-Carnitine Treatment Partially Restores Urinary Bladder Function of Streptozotocin Diabetic Rats
Authors: Gur Serap , İrat Ali Murat
Published: October 2008

Introduction: Diabetes mellitus is associated with urinary bladder dysfunction. This study determined whether or not detrusor responses were altered and reversed by L-carnitine treatment in the urinary bladders of diabetic rats. Materials and Methods: Three groups of animals were used: streptozotocin-treated (45 mg·kg–1 i.p., 8 weeks), parallel L-carnitine-treated (0.6 g·kg–1·day–1 i.p.), and control rats. Contractile and relaxant responses were measured using isolated bath techniques. Results: Serum glucose levels in diabetic rats were partially reversed after L-carnitine treatment. Detrusor strips from diabetic rats exhibited an increase in response to electrical field stimulation (EFS; 0.5–32 Hz). Treatment with L-carnitine restored the hyperreactivity to EFS- induced contractility. The response to direct activation of the smooth muscle with carbachol and KCl remained unaltered. In relaxation studies, the urinary bladders of diabetic rats displayed a diminished response to isoprenaline, an unchanged response to ATP, and an increased response to adenosine of the ATP metabolite. L-Carnitine treatment restored the hyporesponsiveness of isoprenaline and the hyperresponsiveness of adenosine-elicited relaxation. Conclusions: These findings show that carnitine can be implicated in the contractile response of noradrenergic noncholinergic nerve stimulation and the relaxation response of isoprenaline and adenosine. Hence, L-carnitine deficiency can contribute to voiding deficiency in diabetic patients.
Prophylactic Role of Oral L-Arginine on Histological and Contractile Changes in a Rat Chronic Bladder Injury Model
Authors: Özgür Abdurrahman , Önol Fikret Fatih , Ercan Feriha , Tarcan Tufan
Published: October 2008

Introduction: The effect of L-arginine on bladder tissue structure and function in a rat bladder injury model were investigated. Methods: 24 male Sprague-Dawley rats were used. The control group received a regular diet. The L-arginine group received oral L-arginine (1 g/day). The protamine sulfate (PS) group received intravesical PS every 48 h (0.5 ml, 5 mg/ml). L-Arginine was administered to the PS+L-arginine group in addition to PS. At the end of 1 week, bladder tissues were processed for histological and functional studies. Results: The PS group revealed urothelial damage with glycosaminoglycan layer irregularity and mast cell infiltration which was not evident in the PS+L-arginine group. 120 mM potassium and electrical field stimulation (EFS)-induced contractions in the PS group were significantly lower than in other groups, whereas carbachol-induced contractions were not significantly different. Relaxation responses of precontracted strips to EFS and isoproterenol did not reveal a significant decrease in the PS group, whereas L-arginine significantly enhanced these responses in PS-treated animals. Conclusions: Intravesical PS causes urothelial damage and inflammation that is associated with significant changes in rat bladder tissue contractility. Oral L-arginine treatment is found to prevent these histological and contractile alterations. Our findings may indicate the nitric oxide-cGMP pathway as a possible therapeutic target in various bladder diseases associated with urothelial damage.
Rapid Membrane Effect of Testosterone in LNCaP Cells
Authors: Wang Zufeng , Liu Limin , Hou Jianquan , Wen Duangai , Yan Chunyin , Pu Jinxian , Ouyang Jun , Pan Hao
Published: October 2008

Testosterone signaling is widely considered to be mediated through the transcription-regulating intracellular androgen receptor (iAR). In the human prostate cancer cell line LNCaP we demonstrated the presence of unconventional membrane receptors for testosterone (mAR) besides the classic iAR. Binding sides for testosterone on the surface of LNCaP cells were clearly revealed with the membrane-impermeable testosterone-BSA-FITC by confocal laser-scanning microscopy and flow cytometry. Furthermore, we found that testosterone was able to induce a rapid activation of extracellular signal-related kinase 1 and 2 (ERK1/2), but not altered p38 MAPK and c-jun N-terminal kinase (JNK) activity. The testosterone-induced phosphorylation of ERK1/2 could not be inhibited by the AR antagonist cyproterone, excluding the involvement of iAR. Consistent with this finding, the impeded testosterone-BSA was also capable of rapidly phosphorylating ERK1/2, further revealing membrane receptor being responsible for the activation of ERK1/2. Additionally, testosterone-BSA induced a transient expression of c-Fos, which was in a timescale consistent with the rapid ERK1/2 phosphorylation and could be blocked by ERK1/2 inhibitor PD098059, suggesting an ERK1/2-dependent mechanism. Together, these data demonstrated a novel mode of testosterone signaling on LNCaP cells which was not mediated through the classical androgen receptor response, but through unconventional membrane receptors.