bluuebunny/crossref_metadata_2025 huggingface dataset:
Large tectonic movement of the Japan Arc in late Cenozoic times inferred from paleomagnetism: Review and synthesis
Authors: Otofuji Yo‐Ichiro
Published: April 2006

Abstract
Paleomagnetic studies facilitate an understanding of the evolution of the Japan Arc in Cenozoic times from the perspective of tectonic movement. The Japan Arc rifted from the Asian continent in the middle Miocene, while East Asia, including the Japan Arc, moved northward at the same time. The rifting phenomenon of the Japan Arc is described by differential rotation of Southwest and Northeast Japan. Southwest Japan was rotated clockwise through about 45° and Northeast Japan was rotated counter‐clockwise through about 40°. This differential rotation occurred concurrently at about 15 Ma. Eighty percent of the rotation was completed during a period of 1.8 million years. These factors lead us to propose a‘double door’opening mode with a fast spreading rate of 21 cm/yr for the evolution of the Japan Sea, suggesting that the asthenosphere with a low viscosity was injected beneath the Japan Sea area. The large northward motion of East Asia in relation to Europe is expected from the apparent polar wander path constructed from the paleomagnetic data of the Japan Arc. East Asia may have moved northward by more than 1700 km between 20 Ma and 10 Ma accompanied by a slightly clockwise rotation of 10°. The eastern part of the Eurasian plate was subjected to extreme geodynamic conditions in late Cenozoic times.
Temporal variation in primary magma compositions in the northeast Japan Arc
Authors: Yamashita Shigeru , Tatsump Yoshiyljki , Nohda Susumu
Published: April 2006

Abstract
A remarkable temporal variation in primary magma compositions has been found in the Northeast Japan arc. The trench‐side magmas have become more enriched in FeO* and the backarc‐side magmas have become more depleted in FeO* while retaining almost constant SiO, levels for the last ∼20 million years. In order to understand the origin of the temporal variation, FeO* and SiO, contents in partial melts are modeled for an adiabatically‐rising mantle as a function of potential temperature and original composition of the mantle material. The result demonstrates that the primary magmas that are more depleted in FeO* were derived from the mantle materials either at lower potential temperatures or with compositions more depleted in basaltic components. A possible mechanism for the inferred primary magma variability is the change in depth intervals with time of magma production in a compositionally‐layered mantle wedge; greater degrees of depletion at a greater depth is reconciled with a probable thermal regime in the mantle wedge.
A mixed mid‐Permian marine fauna from the Yanji area, northeastern China: A paleobiogeographical reinterpretation
Authors: Shi G. R. , Zwan L‐P.
Published: April 2006

Abstract Paleobiogeographically mixed marine faunas have been well recognized from many Permian marine sequences in northeast China. These mixed faunas are normally associated with Monodiexodina fusulinid assemblages. The mixed faunas are characterized by an admixture of both paleo‐tropical Cathaysian taxa and cool‐temperate elements. In addition, endemic taxa, especially at a specific level, and anti‐tropical forms, are also very distinctive.

Previously, the presence of anti‐tropical taxa in these mixed faunas has been used to argue that some of the northeast Asian terranes may have originated from northern Gondwana during the Permian, where they may have been m close proximity to Tibet. However, this interpretation is contrasted by the view offered in this paper. It is argued that the anti‐tropical distribution of marine taxa is a normal, predictable biogeographical phenomenon that is probably controlled by certain climatic conditions. Permian anti‐tropicality seems to have occurred most strongly during the Late Artinskian to Ufimian, probably in association with the presence of distinct mesothermal climatic zones at the time. In the present study we report a mixed mid‐Permian marine fauna (fusulinids and brachiopods) from the Dasuangou Formation of the Yanji area in the eastern Jilin Province of northeast China, and discuss its possible origin in the context of Permian paleogeography and the climates of eastern Pangea.
Contrasting two types of orogen in Permo‐Triassic Japan: Accretionary versus collisional
Authors: Isozaki Yukio
Published: April 2006

Abstract
Proto‐Japan originated from a continental margin of the Neoproterozoic Yangtze (South China) craton. It represents a unique Permo‐Triassic tectonic setting in western Panthalassa, where two distinct types of orogenic belt occurred side by side. There was an accretionary orogen between the Yangtze craton and the Proto‐Pacific (Farallon) Plate and a collisional orogen between the Sino‐Korean (North China) and Yangtze cratons. This article reviews results of the latest on‐land geological studies concerning Permo‐Triassic tectonics in Japan and proposes a new plate tectonic interpretation as well as a paleogeographic reconstruction of this particularly unique geotectonic regime. Special emphases are given to (i) the accretion processes and products derived by collision‐subduction of the Permian Akiyoshi paleoseamount and Maizuru paleo‐oceanic plateau; (ii) the field occurrence of 220‐Ma Sangun high‐P/T schists and its implication for the exhumation process and ‘tectonic sandwich’ structure; (iii) the extensive development of a subhorizontal nappe of the pre‐Jurassic rocks and their bearing on the orogenic edifice; and (iv) the restricted occurrence of the 250‐Ma collision complex in the Hida and Oki belts and the relevant connection to the Precambrian cratons and collision suture in East Asia. The newly proposed paleogeographic reconstruction is also tested by faunal provinciality of Permo‐Triassic fossils from shallow‐water sediments.
Jurassic accretion tectonics of Japan
Authors: Isozaki Yukio
Published: April 2006

Abstract
The Jurassic accretionary complex and coeval granites in Japan represent remnants of the Jurassic arc‐trench system developed between the Asian continent and Pacific Ocean. The Jurassic accretionary complex occurs as a large‐scale nappe that is tectonically sandwiched between the overlying pre‐Jurassic nappes and underlying post‐Jurassic nappes. By virtue of new research styles (microfossil mapping and chronometric mapping) the following new views of the Jurassic accretionary complex in Japan, that suggest those for on‐land exposed ancient accretionary complexes in general, have been obtained: (i) the accretion age of the Jurassic accretionary complex ranges over ∼ 80 million years from the latest Triassic to earliest Cretaceous according to a reconstructed stratigraphy of component rocks (oceanic plate stratigraphy); (ii) the accretionary complex is subdivided into several nappe units, each characterized by unique oceanic plate stratigraphy; (iii) a tectonically downward‐younging polarity is observed in the piled nappes; (iv) the Jurassic accretionary complex is composed of coherent‐type and chaotic‐type units, the former retaining the primary accretionary structures while the latter are characterized by collapsed and secondarily mixed materialslfabrics derived from the former; (v) the chaotic‐type units predominate in volume over the coherent‐type units; (vi) the accretionary complex suffered from a regional low‐grade metamorphism (up to the lower greenschist facies) within ∼10–20 million years after the accretion timing; and (vii) the lateral extent of the Jurassic accretionary complex in East Asia is intermittently traced from the Koryak mountains in Russia to North Palawan in the west Philippines for ∼6000 km. Discussion focuses on (i) the low preservation ratio of the coherent‐type units to the chaotic‐type units with respect to frequent subduction erosion by seamount subduction; (ii) absence of the Franciscan‐type melange, suggesting sedimentary mixing origin for the chaotic‐type unit; (iii) a growth rate of the Jurassic accretionary complex compatible to modern analogues; and (iv) the total volume of the Jurassic accretionary complex in Japan with respect to the most likely terrigeiious elastics source along the 250 Ma continent‐continent collision suture in central China (between the Sino‐Korean and Yangtze blocks).
Regional metamorphic belts of the Japanese Islands
Authors: Nakajima Takashi
Published: April 2006

Abstract
An overview of the regional metamorphic belts of Japan is given in the context of the tectonic evolution of the Japanese Islands. The Japanese Islands were situated on an active margin of the Eurasian continent or its constituent landmass before their assembly during the Phanerozoic. The Japanese Islands are composed mainly of metamorphosed and unmetamorphosed accretionary complexes, granitoids and their effusive equivalents that were formed by the Cordilleran‐type orogeny. The metamorphic belts are regarded essentially as a deep‐seated portion of an accretionary complex. In spite of continuous subduction of oceanic plates beneath the continents, these orogenic rocks were formed quite episodically, as evidenced by discontinuous matrix ages of the accretionary complexes and a striking concentration of isotopic ages of the granitoids. A systematic along‐arc age shift of Cretaceous large‐scaled granitic magmatism and regional metamorphism suggests a tectonic control such as ridge subduction, which triggered the episodic orogeny. A tectonic model based on the paired metamorphic belts, combined with the non‐steady tectonic control, works well to explain this magmatism and metamorphism in a single arc‐trench system as a continental margin process. However, the juxtapositional process of the paired metamorphic belts is still a problem. Two possible cases, namely transcurrent displacement and back‐arc overthrusting are discussed.
Pacific‐type orogeny revisited: Miyashiro‐type orogeny proposed
Authors: Maruyama Shigenori
Published: April 2006

Abstract
The concept of Pacific‐type orogeny is revised, based on an assessment of geologic data collected from the Japanese Islands during the past 25 years. The formation of a passive continental margin after the birth of the Pacific Ocean at 600 Ma was followed by the initiation of oceanic plate subduction at 450 Ma. Since then, four episodes of Pacific‐type orogeny have occurred to create an orogenic belt 400 km wide that gradually grew both oceanward and downward. The orogenic belt consists mainly of an accretionary complex tectonically interlayered with thin (<2 km thick), subhorizontal, high‐P/T regional metamorphic belts. Both the accretionary complex and the high‐P/T rocks were intruded by granitoids ∼100 million years after the formation of the accretionary complex. The intrusion of calc‐alkaline (CA) plutons was synchronous with the exhumation of high‐P/T schist belts. Ages from microfossils and K‐Ar analysis suggest that the orogenic climax happened at a time of mid‐oceanic ridge subduction. The orogenic climax was characterized by the formation of major subhorizontal orogenic structures, the exhumation of high‐P/T schist belts by wedge extrusion and subsequent domed uplift, and the intrusion‐extrusion of CA magma dominantly produced by slab melting. The orogenic climax ended soon after ridge subduction, and thereafter a new Pacific‐type orogeny began. A single Pacific‐type orogenic cycle may correspond to the interaction of the Asian continental margin with one major Pacific oceanic plate. Ophiolites in Japan occur as accreted material and are not of island‐arc but of plume origin. They presumably formed after the birth of the southern Pacific superplume at 600 Ma, and did not modify the cordilleran‐type orogeny in a major way. Microplates, fore‐arc slivers, intra‐oceanic arc collisions and the opening of back‐arc basins clearly contributed to cordilleran orogenesis. However, they were of secondary importance and served only to modify pre‐existing major orogenic components. The most important cause of cordilleran‐type orogeny is the subduction of a mid‐oceanic ridge, by which the volume of continental crust increases through the transfer of granitic melt from the subducting oceanic crust to an orogenic welt. Accretionary complexes are composed mainly of recycled granitic sediments with minor amounts of oceanic material, which indicate that the accretion of oceanic material, including huge oceanic plateaus, was not significant for orogenic growth. Instead, the formation and intrusion of granitoids are the keys to continental growth, which is the most important process in Pacific‐type orogeny. Collision‐type orogeny does not increase the volume of continental crust. The name ‘Miyashiro‐type orogeny’ is proposed for this revised concept of Pacific‐type or cordilleran‐type orogeny, in order to commemorate Professor A. Miyashiro's many contributions to a better understanding of orogenesis.
The Matsue Formation: Evidence for gross mantle heterogeneity beneath Southwest Japan at 11 Ma
Authors: Morris Paul A. , Itaya Tetsumaru
Published: April 2006

Abstract
Middle Miocene basalts and basaltic andesites of the Matsue Formation outcrop within a 5 km radius of Matsue city in eastern Shimane Prefecture. Despite their limited outcrop and age (11.0 ± 1.5 Ma), they show a wide range in 87Sr‐86Sr(0.70370–0.70593), 143Nd‐144Nd(0.512904–0.512471) and large ion lithophile element (LILE) contents, but a relatively narrow range for some high field strength elements (HFSE) such as Nb and Ti. These basalts and andesites can be divided into three groups based on petrography, major element, trace element and isotope chemistry. Although one group has undergone some fractional crystallization, isotope chemistry precludes linkage of the groups by a closed‐system process. Crustal contamination can explain isotope chemistry, but is not consistent with trace element variations. The most satisfactory model is eruption of two compositionally distinct magmas, with limited magma mixing and fractional crystallization. Published experimental work shows that one end‐member resulted from shallow melting of upwelling mantle at ∼25 km. The simultaneous eruption of the other end member magma in the same area points towards a heterogeneous mantle. The isotopic composition of Matsue Formation basalts and andesites covers the entire range of Late Miocene mafic volcanic rocks of southwest Japan. Such gross heterogeneity developed on a local scale has implications for models that deal with regional chemical variations of mafic volcanic rocks in southwest Honshu.
Small faults and kink bands in the Nankai accretionary complex: Textural observations from Site 808 of ODP Leg 131
Authors: Lewis Jonathan C. , Byrne Tim , Prior David J.
Published: April 2006

Abstract We present backscattered scanning electron microscope and petrographic microscope observations of deformed sediments from Ocean Drilling Program (ODP) Site 808 in order to better understand the dewatering and deformation history of the Nankai accretionary complex. This synthesis of deformation textures has three implications. First, the early structures that dominate the Nankai prism, small faults and kink bands, have very different electron microscope versus optical microscopic expressions. This observation is important to investigations of fine‐grained sediment in both stable and active tectonic settings, in part, because these materials have often been studied almost exclusively by electron microscope methods. In sediments of this type, investigators often forego petrographic analysis because of the relative opacity of samples at normal (i.e. 30 pm) thin section thicknesses. Second, the textural observations we have compiled suggest that these deformation structures acted as ‘single‐event’ pathways that contributed to diffusive dewatering of the prism. Third, our observations serve as a reference frame for the early tectonic structures that are important to the dewatering history of a ‘sandy’ accretionary prism.
Asymmetric X‐ray diffraction peak of metamorphosed carbonaceous material
Authors: Itaya Tetsumaru , Tomuro Morio , Ninagawa Kiyotaka
Published: April 2006

Abstract It was revealed that the asymmetric X‐ray diffraction peak of metamorphosed carbonaceous material was a combination of two types of symmetric peaks from the coaly material and graphite crystallite. Numerical synthesis using the two symmetric peaks shows the graphitization process observed in a metamorphic sequence is accompanied by a continuous change of the peak shape and apparent interplanar spacing. Based on the analytical results and geological observations, it is suggested that graphitization of carbonaceous material consists of two processes: (i) the formation of graphite crystallites at the expense of the coaly material through the formation of transitional material and the increasing abundance of crystallites which is observed in the chlorite zone; and (ii) growth of crystallites forming well‐ordered graphite, which occurs in the higher‐grade zone.
The seismogenic zone of subduction thrust faults
Authors: Hyndman R. D. , Yamano M. , Oleskevich D. A.
Published: April 2006

Abstract Subduction thrust faults generate earthquakes over a limited depth range. They are aseismic in their seaward updip portions and landward downdip of a critical point. The seaward shallow aseismic zone, commonly beneath accreted sediments, may be a consequence of unconsolidated sediments, especially stable‐sliding smectite clays. Such clays are dehydrated and the fault may become seismogenic where the temperature reaches 100‐‐150°C, that is, at a 5‐‐15 km depth. Two factors may determine the downdip seismogenic limit. For subduction of young hot oceanic lithosphere beneath large accretionary sedimentary prisms and beneath continental crust, the transition to aseismic stable sliding is temperature controlled. The maximum temperature for seismic behavior in crustal rocks is ∼ 350°C, regardless of the presence of water. In addition, great earthquake ruptures initiated at less than this temperature may propagate with decreasing slip to where the temperature is ∼ 450°C. For subduction beneath thin island arc crust and beneath continental crust in some areas, the forearc mantle is reached by the thrust shallower than the 350°C temperature. The forearc upper mantle probably is aseismic because of stable‐sliding serpentinite hydrated by water from the underthrusting oceanic crust and sediments. For many subduction zones the downdip seismogenic width defined by these limits is much less than previously assumed. Within the narrowly defined seismic zone, most of the convergence may occur in earthquakes. Numerical thermal models have been employed to estimate temperatures on the subduction thrust planes of four continental subduction zones. For Cascadia and Southwest Japan where very young and hot plates are subducting, the downdip seismogenic limit on the subduction thrust is thermally controlled and is shallow. For Alaska and most of Chile, the forearc mantle is reached before the critical temperature, and mantle serpentinite provides the limit. In all four regions, the seismogenic zones so defined agree with estimates of the extent of great earthquake rupture, and with the downdip extent of the interseismic locked zone.
A new model of back‐arc spreading in the Parece Vela Basin, northwest Pacific margin
Authors: Kasuga Shigeru , Ohara Yasuhiko
Published: April 2006

Abstract Swath bathymetric data, single‐channel seismic reflection profiles, magnetic and gravity anomalies in the northern part of the Parece Vela (West Mariana) Basin were obtained by comprehensive surveys conducted by the Hydrographic Department of Japan. The central zone of the Parece Vela Basin is characterized by the north‐south trending chain of depressions in a right‐stepping en echelon alignment. The morphology of these depressions is diamond shaped and bordered by steep escarpments of 1000‐1500 m relative height. These fault escarpments extend northeastward and southwestward from the depressions into the surrounding basin floor and then gradually fade out. These escarpments have an S‐shaped trend, and their geometry seems to be symmetric about the depressions. Minor ridges and troughs trending orthogonal to these escarpments are recognized. It is concluded that these depressions and escarpments are the topographic expression of extinct spreading axes and S‐shaped transform faults, respectively. The age of the central depressions seems to be young, although details of tectonic processes forming them remains unsolved. The western province of the basin floor and basement is extremely rugged and characterized by minor ridges and troughs trending in a north‐south direction. Although magnetic anomalies of the basin are very weak, magnetic lineations trending parallel to the topographic trend are recognizable in the central and western parts of the basin. Based on updated geomorpholog‐ical features and magnetic anomalies revealed by the present survey, together with the previously published data including drilling results, it is proposed that the evolution of Parece Vela Basin took place in four stages of opening and tectonic activity: rifting, east‐west spreading, northeast‐southwest spreading with counter‐clockwise rotation of spreading axes, and post‐spreading deformation and volcanism. This proposed spreading model of the Parece Vela Basin is similar to that of the adjacent Shikoku Basin. The spreading axes of both basins were segmented and gradually rotated counter‐clockwise in a later phase of the basin evolution, after the cessation of relatively uniform spreading nearly in an east‐west direction.
Imaging of convergent zones by seismic acquisition and processing
Authors: Talwani Manik , Kessinger Walter
Published: April 2006

Abstract The complex crustal geology of convergent zones requires carefully planned seismic experiments for accurate imaging. Situations that require 2‐D or 3‐D experiments, pre‐stack or post‐stack processing, and time or depth migration, are discussed. Some of the advanced techniques available for seismic processing are described. Some results of 3‐D post‐stack depth migration of a 3‐D data set on the Barbados margin that were obtained by the University of Texas Institute of Geophysics and reprocessed at the Houston Advanced Research Center illustrate the advantage of three‐dimensionality, and the value of advanced processing techniques.
The effects of television food advertisement on children's food purchasing requests
Authors: AKTAŞ ARNAS YAŞARE
Published: April 2006

Background: Children's eating habits and their food consumption have direct relations with obesity, diabetes, cancers, hypertension and coronary heart disease. Television advertisements directly affect children's eating habits and their food consumption. This study was conducted in order to examine television advertisements and children's food consumption while watching television and their desire to purchase goods that they see on television advertisements.

Methods: In the first stage of the study, content analysis of the television advertisements was conducted. In the second stage of the study, a questionnaire (check list) was developed in order to examine children's food consumption while watching television and their purchasing requests while shopping in the supermarket. It was given to 347 mothers who have children aged between 3 and 8 years.

Results: When the results of the study were examined it was found that the time devoted to children's programs was approximately 121 min and the advertisements during this period were approximately 35 min. A total of 344 of the 775 television advertisements shown were related to food. It was also found that most of the food advertisements were about candy/chocolate, chips, milk and milk products such as cheese, yoghurt, and breakfast cereals. The results also revealed that 89.6% of the children either drank or ate something while watching television and the food they consumed most while watching television were fruits, soft drinks, popcorn/nuts, cake, chips and candy/chocolate. The results also revealed that 40.3% of the children asked their parents to purchase the goods that they saw on the television advertisements and that 8.9% of them argued with their parents and/or cried in order for their parents to buy that particular product. It was found that the children tended to request more sweetened products such as candy, ice‐cream, biscuit, cake or soft drinks.

Conclusion: More than half of the food presented in television advertisements were rich in fat and sugar. Children ask their parents to buy the goods they see on television advertisements both while watching television and while shopping. Television advertisements especially affect young children's unhealthy food consumption.
Late‐onset ornithine transcarbamylase deficiency in male patients: Prognostic factors and characteristics of plasma amino acid profile
Authors: HARADA EIMEI , NISHIYORI ATSUSHI , TOKUNAGA YASUYUKI , WATANABE YORIKO , KURIYA NORIKAZU , KUMASHIRO RYUKICHI , KUNO TATEO , KUROMARU RYUICHI , HIROSE SHINICHI , ICHIKAWA KOTARO , YOSHINO MAKOTO
Published: April 2006

Background: The occurrence of male patients with ornithine transcarbamylase (OTC) deficiency during adolescence or in adulthood has now been recognized. The aim of this study was to determine the prognostic factors that affect the prognosis of life, to explore a basis for therapeutic strategy.

Methods: In 10 patients, nine of whom carried the R40H mutation and the other one carrying the Y55D mutation in the OTC gene, 32 demographic and laboratory data were first compared between survivors and non‐survivors, using the unpaired t‐test. The factors with significant difference were then subjected to multiple regression analysis.

Results: The factors that exhibited significant difference were: age at onset, concentration of plasma ammonium, blood pH, and concentrations of six amino acids in plasma. The multiple regression analysis then revealed concentrations of ammonium, leucine, lysine, isoleucine, phenylalanine, glutamine and proline to be significant prognostic factors. The amino acid profile in the 10 patients showed increases in glutamine, proline, lysine, valine and methionine, and decreases in serine, ornithine and arginine. There was an inverse correlation between the age at onset and the level of the residual hepatic OTC activity.

Conclusion: The results implied that: (i) the plasma amino acid profile was unique, in comparison to other liver diseases; (ii) the plasma concentration of each of the (mentioned above) six amino acids was a significant predictor of prognosis; and (iii) suppression of protein catabolism, as suggested by the higher concentrations in isoleucine and leucine in the non‐survivors, prevention of glutamine‐induced brain edema, correction of alkalosis, and supplementation with ornithine or arginine may improve the prognosis of life.
Use of a cyclo‐oxygenase 2 inhibitor for prophylaxis of cystoid macular oedema following cataract surgery: a randomized placebo‐controlled trial
Authors: Riley Andrew F , Wakely Laura A , Patel Hussain Y , Neveldsen Bridget , Purdie Gordon L , Wells Anthony P
Published: April 2006

Abstract

Background:  To assess the efficacy of Celecoxib, a cyclo‐oxygenase 2 (COX‐2) inhibitor, as prophylaxis for cystoid macular oedema after routine cataract surgery.

Methods:  A prospective, randomized, double‐blind placebo‐controlled trial of 69 hospital patients undergoing cataract surgery. Celecoxib 200 mg twice daily or placebo was given immediately after surgery for 14 days. Optical coherence tomography was used to quantify macular thickness before surgery and on day 1, week 2 and week 6 after surgery.

Results:  Sixty‐nine patients were enrolled, of which 33 received placebo and 36 received active drug. Clinically apparent cystoid macular oedema occurred in four of the treatment group and two of the placebo group (P = 0.68). No difference in best‐corrected visual acuity was seen at 6 weeks (P = 0.37). Covariate analysis of the results at 2 weeks and 6 weeks showed a macular thickness of 3% less in the treatment group compared with placebo (P = 0.050).

Conclusion:  Celecoxib may decrease macular thickening following routine cataract surgery at 2 and 6 weeks after surgery as measured by Stratus OCT III. No difference in best‐corrected visual acuity or clinically apparent cystoid macular oedema was seen. Further investigation of COX‐2 inhibitors in a larger prospective randomized trial is required.
Socioeconomic and rural differences for cataract surgery in Western Australia
Authors: Ng Jonathon Q , Morlet Nigel , Semmens James B
Published: April 2006

Abstract

Background:  To examine the relationship between socioeconomic factors, residential locality and cataract surgery incidence.

Methods:  This was a population‐based study using the Western Australian Data Linkage System to identify all cataract operations performed in patients aged 50+ years in 1996 and 2001. Patients’ residential addresses at the time of operation were geocoded to census localities. Using census‐derived indices, procedures were categorized into socioeconomic groups and residential locations (metropolitan and rural). Poisson regression was used to analyse for differences in procedure rates.

Results:  The crude cataract surgery rate in Western Australia increased from 4458 to 6631 procedures per million person‐years between 1996 and 2001. Female and older patients underwent more surgery. Metropolitan residents were more likely to undergo surgery compared with rural residents; a difference that increased by 17% between 1996 and 2001 (1996: incidence rate ratio [IRR] 1.07, 95% confidence interval [CI] 1.02–1.13; 2001: IRR 1.24, 95% CI 1.18–1.29). A pronounced ‘U‐shaped’ pattern of difference had developed for socioeconomic disadvantage by 2001. The most advantaged underwent 9% more surgery than the most disadvantaged. Rates in the middle two groups were less than the lowest one.

Conclusion:  There was growing inequity in the rates of cataract surgery for rural and poorer patients between 1996 and 2001. These differences partly reflect the increasingly two‐tiered Australian health system with more privately provided cataract surgery in urban areas.
Fatigue of shot peened 7075‐T7351 SENB specimen – A 3‐D analysis
Authors: HONDA T. , RAMULU M. , KOBAYASHI A. S.
Published: April 2006

As‐received or shot peened 7075‐T7351 single‐edged notch bend (SENB) specimens, 8.1‐mm thick, were fatigued at a constant maximum load and at stress ratios of R= 0.1 and 0.8 to predetermined numbers of fatigue cycles or to failure. The SENB specimens were then fractured by overload and the tunnelling crack profiles were recorded. The crack‐growth rate, da/dN, after crack initiation at the notch was determined by crack‐profile measurement and fractography at various fatigue cycles. The shot peened surface topography and roughness was also evaluated by three‐dimensional (3‐D) laser scanning microscopy. Residual stresses in the as‐received specimens and those generated by shot peening at Almen scales of 0.004A, 0.008A, 0.012A and 0.016A, were measured by an X‐ray diffraction stress analyser with an X‐ray target, CrK, every 0.1 mm to a depth of 1 mm. The 3‐D stress intensity factor of the curved crack front was determined by the superposition of the 3‐D finite element solutions of the stress intensity factor of the loaded SENB specimen without the residual stress and the stress intensity factor of the unloaded SENB specimen with a prescribed residual stress distribution. da/dN versus the resultant stress intensity factor amplitude, ΔKI, plots showed that while the residual stress locally retarded the crack‐growth rate it had no effect on the overall crack‐propagation rate.
Prediction of the main cortical areas and connections involved in the tactile function of the visual cortex by network analysis
Authors: Négyessy László , Nepusz Tamás , Kocsis László , Bazsó Fülöp
Published: April 2006

We explored the cortical pathways from the primary somatosensory cortex to the primary visual cortex (V1) by analysing connectional data in the macaque monkey using graph‐theoretical tools. Cluster analysis revealed the close relationship of the dorsal visual stream and the sensorimotor cortex. It was shown that prefrontal area 46 and parietal areas VIP and 7a occupy a central position between the different clusters in the visuo‐tactile network. Among these structures all the shortest paths from primary somatosensory cortex (3a, 1 and 2) to V1 pass through VIP and then reach V1 via MT, V3 and PO. Comparison of the input and output fields suggested a larger specificity for the 3a/1‐VIP‐MT/V3‐V1 pathways among the alternative routes. A reinforcement learning algorithm was used to evaluate the importance of the aforementioned pathways. The results suggest a higher role for V3 in relaying more direct sensorimotor information to V1. Analysing cliques, which identify areas with the strongest coupling in the network, supported the role of VIP, MT and V3 in visuo‐tactile integration. These findings indicate that areas 3a, 1, VIP, MT and V3 play a major role in shaping the tactile information reaching V1 in both sighted and blind subjects. Our observations greatly support the findings of the experimental studies and provide a deeper insight into the network architecture underlying visuo‐tactile integration in the primate cerebral cortex.
Cystamine and cysteamine prevent 3‐NP‐induced mitochondrial depolarization of Huntington's disease knock‐in striatal cells
Authors: Mao Zhengkuan , Choo Yeun Su , Lesort Mathieu
Published: April 2006

Cystamine significantly improved motor deficits and extended survival in mouse models of Huntington's disease (HD); however, the precise mechanism(s) by which cystamine and the related compound cysteamine are beneficial remain to be elucidated. Using clonal striatal cell lines from wild‐type (STHdhQ7/HdhQ7) and mutant huntingtin knock‐in (STHdhQ111/HdhQ111) mice, we have tested the hypothesis that cystamine and cysteamine could be beneficial by preventing the depolarization of mitochondria in cell cultures. Treatment with 3‐nitroproprionic acid (3‐NP), a mitochondrial complex II inhibitor, induces mitochondrial depolarization and cell death of mutant HD striatal cells but not of wild‐type cells. The 3‐NP‐mediated decrease in the mitochondrial membrane potential was attenuated by 50 µmcystamine and completely inhibited by 250 µmcystamine. Similar results were obtained using cysteamine (50–500 µm). In addition, both cystamine and cysteamine significantly attenuated the 3‐NP‐induced cell death. Treatment of mutant HD striatal cells with 3‐NP resulted in a robust decrease in the cellular and mitochondrial levels of glutathione (GSH) compared with cells exposed to the vehicle alone. Pre‐treatment of the cells with cystamine and cysteamine completely prevented the 3‐NP‐mediated decrease in cellular and mitochondrial GSH levels. Incubation withl‐buthionine (S,R) sulfoximine (BSO) 250 µmin combination with cystamine (250 µm) or cysteamine (250 µm) prior to being treated with 3‐NP completely prevented the beneficial effects of cystamine and cysteamine on the 3‐NP‐mediated mitochondrial depolarization. These results demonstrate that cystamine and cysteamine prevent the 3‐NP‐induced mitochondrial depolarization of HD striatal cell cultures.
Short‐ and long‐term modulation of upper limb motor‐evoked potentials induced by acupuncture
Authors: Maioli Claudio , Falciati Luca , Marangon Mattia , Perini Sergio , Losio Antonio
Published: April 2006

The aim of this study was to investigate in humans the effects of acupuncture upon upper‐limb motor‐evoked potentials (MEPs), elicited by transcranial magnetic stimulation of the primary motor cortex. It is known that peripheral sensory stimulation can be used to induce short‐ and long‐term changes in motor cortex excitability. Data show that the simple insertion of the needle is an adequate somatosensory stimulus to induce a significant modulation of MEP amplitude, the sign of which (facilitation or inhibition) is specific to the investigated muscle and to the point of needle insertion. Moreover, MEP changes in upper‐limb muscles are also observed following needling of lower‐limb sites, revealing the presence of long‐distance effects of acupuncture. Finally, the modulation in muscle excitability considerably outlasts the time period of needle application, demonstrating the induction of long‐term plastic changes in the central nervous system. In addition, results have shown that the effects on muscle excitability are not restricted to the stimulation of well‐coded acupoints, as described in traditional Chinese medicine, but they can also be induced by needling of nonacupoints, normally not used for therapeutic purposes. The possible neuronal mechanisms underlying the observed effects of acupuncture are discussed in relation to the available neurophysiological data regarding the interlimb reflexes and the changes in the representational cortical maps induced in humans by a prolonged somatosensory stimulation.
Rule‐dependent shifting of sensorimotor representation in the primate prefrontal cortex
Authors: Amemori Ken‐ichi , Sawaguchi Toshiyuki
Published: April 2006

When we react to the outer world, perceived sensory information is frequently memorized over a temporal interval then transformed into a motor command based on a behavioural rule. In this type of memory‐based sensorimotor transformation, working memory is considered to play an important role. It has been suggested that the lateral prefrontal cortex is involved in the process of the working memory. However, the neuronal mechanism for guiding a motor command from the working memory has not been established. To examine how visuospatial working memory is linked with a forthcoming saccade direction, we used an antisaccade paradigm for monkeys in which a behavioural rule was presented in the middle of a delay period. In this task, the subjects were required to maintain cue location and to select a response based on a behavioural rule. We found that a subset of mnemonic neurons in the lateral prefrontal cortex changed their representation from cue to saccade direction. Furthermore, the discriminability for saccade direction of these neurons tended to appear soon after the behavioural rule presentation, indicating their significant dependency on the behavioural rule. These results suggest that a subset of mnemonic neurons in the lateral prefrontal cortex change their activity depending on a behavioural rule to guide a prospective motor command.
Accumulation of the inhibitory receptor EphA4 may prevent regeneration of corticospinal tract axons following lesion
Authors: Fabes Jez , Anderson Patrick , Yáñez‐Muñoz Rafael J. , Thrasher Adrian , Brennan Caroline , Bolsover Stephen
Published: April 2006

We have examined the expression of Eph receptors and their ephrin ligands in adult rat spinal cord before and after lesion. Neurons in adult motor cortex express EphA4 mRNA, but the protein is undetectable in uninjured corticospinal tract. In contrast, after dorsal column hemisection EphA4 protein accumulates in proximal axon stumps. One of the ligands for EphA4, ephrinB2, is normally present in the grey matter flanking the corticospinal tract but after injury is markedly up‐regulated in astrocytes in the glial scar. The result is that, after a lesion, corticospinal tract axons bear high levels of EphA4 and are surrounded to front and sides by a continuous basket of cognate inhibitory ephrin ligand. We suggest that a combination of EphA4 accumulation in the injured axons and up‐regulation of ephrinB2 in the surrounding astrocytes leads to retraction of corticospinal axons and inhibition of their regeneration in the weeks after a spinal lesion.
Role of intracellular Ca2+ and calmodulin/MAP kinase kinase/extracellular signal‐regulated protein kinase signalling pathway in the mitogenic and antimitogenic effect of nitric oxide in glia‐ and neurone‐derived cell lines
Authors: Meini Antonella , Garcia Julian Blanco , Pessina Gian Paolo , Aldinucci Carlo , Frosini Maria , Palmi Mitri
Published: April 2006

To elucidate the mechanism of cell growth regulation by nitric oxide (NO) and the role played in it by Ca2+, we studied the relationship among intracellular Ca2+ concentration ([Ca2+]i), mitogen‐activated protein kinases [extracellular signal‐regulated protein kinase (ERK)] and proliferation in cell lines exposed to different levels of NO. Data showed that NO released by low [(z)‐1‐[2‐aminiethyl]‐N‐[2‐ammonioethyl]amino]diazen‐1‐ium‐1,2diolate (DETA/NO) concentrations (10 µm) determined a gradual, moderate elevation in [Ca2+]i (46.8 ± 7.2% over controls) which paralleled activation of ERK and potentiation of cell division. Functionally blocking Ca2+ or inhibiting calmodulin or MAP kinase kinase activities prevented ERK activation and antagonized the mitogenic effect of NO. Experimental conditions favouring Ca2+ entry into cells led to increased [Ca2+]i (189.5 ± 4.8%), ERK activation and cell division. NO potentiated the Ca2+ elevation (358 ± 16.8%) and ERK activation leading to expression of p21Cip1 and inhibition of cell proliferation. Furthermore, functionally blocking Ca2+ down‐regulated ERK activation and reversed the antiproliferative effect of NO. Both the mitogenic and antimitogenic responses induced by NO were mimicked by a cGMP analogue whereas they were completely antagonized by selective cGMP inhibitors. These results demonstrate for the first time that regulation of cell proliferation by low NO levels is cGMP dependent and occurs via the Ca2+/calmodulin/MAP kinase kinase/ERK pathway. In this effect the amplitude of Ca2+ signalling determines the specificity of the proliferative response to NO possibly by modulating the strength of ERK activation. In contrast to the low level, the high levels (50–300 µm) of DETA/NO negatively regulated cell proliferation via a Ca2+‐independent mechanism.
Enhanced perisomatic inhibition and impaired long‐term potentiation in the CA1 region of juvenile CHL1‐deficient mice
Authors: Nikonenko Alexander G. , Sun Mu , Lepsveridze Eka , Apostolova Ivayla , Petrova Iveta , Irintchev Andrey , Dityatev Alexander , Schachner Melitta
Published: April 2006

The cell adhesion molecule, CHL1, like its close homologue L1, is important for normal brain development and function. In this study, we analysed the functional role of CHL1 in synaptic transmission in the CA1 region of the hippocampus using juvenile CHL1‐deficient (CHL1–/–) and wild‐type (CHL1+/+) mice. Inhibitory postsynaptic currents evoked in pyramidal cells by minimal stimulation of perisomatically projecting interneurons were increased in CHL1–/– mice compared with wild‐type littermates. Also, long‐term potentiation (LTP) at CA3–CA1 excitatory synapses was reduced under physiological conditions in CHL1‐/– mice. This abnormality was abolished by application of a GABAA receptor antagonist, suggesting that enhanced inhibition is the cause of LTP impairment. Quantitative ultrastructural and immunohistochemical analyses revealed aberrations possibly related to the abnormally high inhibition observed in CHL1–/– mice. The length and linear density of active zones in symmetric synapses on pyramidal cell bodies, as well as number of perisomatic puncta containing inhibitory axonal markers were increased. Density and total number of parvalbumin‐positive interneurons was also abnormally high. These observations and the finding that CA1 interneurons express CHL1 protein indicate that CHL1 is important for regulation of inhibitory synaptic transmission and interneuron populations in the postnatal brain. The observed enhancement of inhibitory transmission in CHL1–/– mice is in contrast to the previous finding of reduced inhibition in L1 deficient mice and indicates different functions of these two closely related molecules.
Nitric oxide‐dependent long‐term potentiation revealed by real‐time imaging of nitric oxide production and neuronal excitation in the dorsal horn of rat spinal cord slices
Authors: Ikeda Hiroshi , Kusudo Kei , Murase Kazuyuki
Published: April 2006

Nitric oxide (NO) is thought to be involved in the central mechanism of hyperalgesia and allodynia at the spinal level. Recently, we reported that NO played an important role in the induction of long‐term potentiation (LTP) of synaptic strength in spinal dorsal horn, which is believed to underlie hyperalgesia and allodynia. In this study, to elucidate the relationship of NO to LTP in spinal dorsal horn, we measured the spatiotemporal distribution of NO signal with the NO‐sensitive dye, DAR‐4M, and neuronal excitation with the voltage‐sensitive dye, RH482, in rat spinal cord slices, elicited by dorsal root stimulation. In superficial dorsal horn, neuronal excitation evoked by C fiber‐activating dorsal root stimulation was potentiated for more than 2 h after low‐frequency conditioning stimulation (LFS, 240 pulses at 2 Hz for 2 min). In the same slices that exhibited LTP, NO was produced and distributed in the superficial dorsal horn during the delivery of LFS, and the amplitude of LTP and amount of NO production showed close correlation from slice to slice. LTP and production of NO were inhibited in the presence of the NO synthase inhibitors and an inhibitor of heme oxygenase, the synthetic enzyme for carbon monoxide (CO). These results suggest that production and distribution of NO is necessary for the induction of LTP in spinal dorsal horn, and that CO contributes to the LTP induction and NO production by LFS.
Reduction in subthalamic 8–35 Hz oscillatory activity correlates with clinical improvement in Parkinson's disease
Authors: Kühn Andrea A. , Kupsch Andreas , Schneider Gerd‐Helge , Brown Peter
Published: April 2006

Strong synchronization of neuronal activity occurs in the 8–35 Hz band in the subthalamic nucleus (STN) of patients with Parkinson's disease (PD) and is evident as oscillatory local field potential (LFP) activity. To test whether such synchronization may contribute to bradykinesia and rigidity, we sought correlations between the suppression of synchronization at 8–35 Hz in STN and the reduction in Parkinsonism with levodopa. LFPs were recorded on and off medication from STN deep‐brain stimulation electrodes in nine PD patients. LFP power was calculated over the frequencies of the most prominent spectral peak within the 8–35 Hz frequency band on each of 17 sides (off medication), and over the frequencies of any peak in the 60–90 Hz band, if present (seven sides, on medication). Levodopa‐induced reduction of LFP power over these two frequency ranges was then correlated with improvement in motor impairment as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS). The reduction in peak activity in the 8–35 Hz band with levodopa positively correlated with the improvement in the contralateral hemibody motor UPDRS score with levodopa (r = 0.811, P < 0.001) as well as with hemibody subscores of akinesia‐rigidity (r = 0.835, P < 0.001), but not tremor. A trend for negative correlations was found between peak 60–90 Hz LFP power and UPDRS hemibody score, suggesting that positive correlations were relatively frequency‐specific. Our results support a link between levodopa‐induced improvements in bradykinesia and rigidity and reductions in population synchrony at frequencies < 35 Hz in the region of the STN in patients with PD.