bluuebunny/crossref_metadata_2025 huggingface dataset:
A high‐resolution diatom record of late‐Quaternary sea‐surface temperatures and oceanographic conditions from the eastern Norwegian Sea
Authors: BIRKS CHRISTOPHER J. A. , KOÇ NALÂN
Published: July 2010

Core MD95‐2011 was taken from the eastern Vøring Plateau, near the Norwegian coast. The section between 250 and 750 cm covers the time period from 13 000 to 2700 cal. yr BP (the Lateglacial and much of the Holocene). Samples at 5 cm intervals were analysed for fossil diatoms. A data‐set of 139 modern sea‐surface diatom samples was related to contemporary sea‐surface temperatures (SSTs) using two different numerical methods. The resulting transfer functions were used to reconstruct past sea‐surface temperatures from the fossil diatom assemblages. After the cold Younger Dryas with summer SSTs about 6°C, temperatures warmed rapidly to about 13°C. One of the fluctuations in the earliest Holocene can be related to the Pre‐Boreal Oscillation, but SSTs were generally unstable until about 9700 cal. yr BP. Evidence from diatom concentration and magnetic susceptibility suggests a change and stabilization of water currents associated with the final melting of the Scandinavian Ice Sheet at c. 8100 cal. yr BP. A period of maximum warmth between 9700 and 6700 cal. yr BP had SSTs 3–5°C warmer than at present. Temperatures cooled gradually until c. 3000 cal. yr BP, and then rose slightly around 2750 cal. yr BP. The varimax factors derived from the Imbrie & Kipp method for sea‐surface‐temperature reconstructions can be interpreted as water‐masses. They show a dominance of Arctic Waters and Sea Ice during the Younger Dryas. The North Atlantic current increased rapidly in strength during the early Holocene, resulting in warmer conditions than previously. Since about 7250 cal. yr BP, Norwegian Atlantic Water gradually replaced the North Atlantic Water, and this, in combination with decreasing summer insolation, led to a gradual cooling of the sea surface. Terrestrial systems in Norway and Iceland responded to this cooling and the increased supply of moisture by renewed glaciation. Periods of glacial advance can be correlated with cool oscillations in the SST reconstructions. By comparison with records of SSTs from other sites in the Norwegian Sea, spatial and temporal changes in patterns of ocean water‐masses are reconstructed, to reveal a complex system of feedbacks and influences on the climate of the North Atlantic and Norway.
Seasonal and interannual variability of Siberian river discharge in the Laptev Sea inferred from stable isotopes in modern bivalves
Authors: MUELLER‐LUPP THOMAS , ERLENKEUSER HELMUT , BAUCH HENNING A.
Published: July 2010

Stable oxygen and carbon isotope profiles from modern bivalve shells were investigated in order to reconstruct short‐term hydrographical changes in the river‐shelf system of the Laptev Sea. Oxygen isotopic profiles obtained from the aragonitic speciesAstarte borealisexhibit amplitude cycles interpreted as annual hydrographical cycles. These records reflect the strong contrast between summer and winter bottom water conditions in the Laptev Sea. The seasonal variations in δ18O are mainly controlled by the riverine freshwater discharge during summer with 0.5‰ per salinity unit. Corrected for a defined species‐dependent fractionation offset of ‐0.37‰, time‐dependent salinity records were reconstructed from these δ18O profiles. They indicate a good correspondence to seasonal hydrographic changes and synoptical data. Persistent trends with shell growth towards more negative δ13C values are observed in all specimens and appear to be related to metabolic changes of the bivalves during ontogeny. In contrast, short‐term fluctuations are likely linked to seasonal variabilities of the river water outflow patterns and enhanced phytoplankton productivity during summer. This is corroborated by a clear watermass‐related distinction of the various δ13C records made on the basis of water depth and distance from the riverine source.
Holocene humidity fluctuations in Sweden inferred from dendrochronology and peat stratigraphy
Authors: GUNNARSON BJÖRN ERIK , BORGMARK ANDERS , WASTEGÅRD STEFAN
Published: July 2010

Tree‐ring and peat stratigraphy data were examined back to 5000 BC in order to identify and compare humidity changes in Fennoscandia. The temporal variation in distribution of Scots pine (Pinus sylvestris L.) was used as a measure of past lake‐level fluctuations in central Sweden. The chronology, which spans 2893 BC–AD 1998 with minor gaps in AD 887–907 and 1633–1650 BC and with additional floating chronologies back to 4868 BC, was cross‐dated and fixed to an absolute timescale using a chronology from Torneträsk, northern Sweden. The peat stratigraphy from the Stömyren peat bog, south‐central Sweden, was transformed into humification indices to evaluate humidity changes during the past 8000 years. The peat chronology is established by four tephra datings and eight 14C datings. Synchronous periods of drier conditions, interpreted from regeneration and the mortality pattern of pine, tree‐ring chronology and peat humification, were recognized at c. 4900–4800 BC, 2400–2200 BC, 2100–1800 BC, 1500–1100 BC, AD 50–200, AD 400–600 and AD 1350–1500. Possible wetter periods were encountered at 3600–3400 BC, 3200–2900 BC, 2200–2100 BC, 1700–1500 BC, 1100–900 BC, 100 BC‐AD 50, AD 200–400, AD 750–900 and AD 1550–1700. The wet and dry periods revealed by the tree rings and peat stratigraphy data indicate considerable humidity changes in the Holocene.
Holocene palaeoecology and shoreline displacement on the Biskopsmåla Peninsula, southeastern Sweden
Authors: YU SHI‐YONG , ANDRÉN ELINOR , BARNEKOW LENA , BERGLUND BJÖRN E. , SANDGREN PER
Published: July 2010

High‐resolution palaeoecological proxies of pollen, macrofossils and diatoms from an isolation lake provide a long‐term record of the Holocene landscape history and shoreline displacement on the Biskopsmåla Peninsula in central Blekinge, SE Sweden. During the Preboreal/Boreal transition, the peninsula was sparsely vegetated by woodlands, along with lateglacial dwarf shrub/steppe communities. The lake basin was isolated from the shallow Yoldia Sea during this time. The regional climate improved from 10 700 cal. BP, evident as progressive expansion of Pinus‐dominated mixed forest with deciduous trees. The lake basin was probably connected with the Ancylus Lake during the period 10700–10 100 cal. BP. Subsequently the basin became isolated again, corresponding to the Early Littorina Sea phase. Replacement of freshwater diatoms by those with brackish‐water affinity at 8100 cal. BP indicates the initial transgression of the Littorina Sea in this basin. But not until 7500 cal. BP were brackish conditions fully established. Peaks of brackish‐marine diatoms and dinoflagellates during 7500–7000 cal. BP indicate increased saltwater inflow to the Baltic Sea in response to global meltwater pulse 3. However, interactive changes in seagrass and stonewort macrofossil concentrations suggest that three minor transgressions during 5900–5300, 5000–4700 and 4400–4000 cal. BP occurred locally, associated with centennial‐scale variations in regional wind pattern or coastal storminess. By 3000 cal. BP, the lake basin was finally isolated from the Baltic, and thereafter the landscape on the peninsula became gradually more influenced by human activities.
Reconstructions of western Ross Sea palaeo‐ice‐stream grounding zones from high‐resolution acoustic stratigraphy
Authors: HOWAT IAN M. , DOMACK EUGENE W.
Published: July 2010

This study analyses acoustic profiles of two mid‐shelf troughs, the JOIDES Basin and Pennell Trough in the western Ross Sea, Antarctica. These troughs are subglacial erosion features formed by repeated advance of streaming ice onto the Ross Sea continental shelf. Sediment wedge formations, interpreted to have been deposited at the most seaward grounding zone during the Last Glacial Maximum (LGM), are observed within the mid‐shelf region of these troughs. By correlating high‐resolution acoustic profiles with core samples, we resolve the stratigraphy of these wedge formations to assess the relationships between bathymetry, subglacial sediment distribution and palaeo‐ice‐stream configuration. The grounding zone wedge geometries were controlled by the pre‐existing topography. The JOIDES and Pennell Troughs were only partially infilled during the LGM. Axial diamict progradation from the landward margin of the troughs indicates enhanced flow (debris supply) along the axis of ice flow. Differences in grounding zone geometries indicate a decrease in basal debris deposition and/or supply during ice recession. The lack of a recessional ice‐shelf facies indicates that either the ice shelf was absent during retreat, or that there was no melt‐out of basal debris.
Glacial erosion beneath ice streams and ice‐stream tributaries: constraints on temporal and spatial distribution of erosion from numerical simulations of a West Antarctic ice stream
Authors: BOUGAMONT MARION , TULACZYK SLAWEK
Published: July 2010

Geologic evidence such as subglacial troughs and grounding zone wedges indicate that soft‐bedded, West Antarctic ice streams are capable of eroding, transporting and depositing large volumes of debris at high rates (˜100 m3 yr‐1 per meter width). In order to understand the dynamics of ice streams and the geologic effects of their activity, it is important to understand the physical mechanisms that control these high rates of sub‐ice‐stream sediment generation and transport. Here, we use a numerical model of Ice Stream C run over c. 8500 model years to quantify the effects of a recently proposed, till‐ploughing mechanism of till formation and redistribution beneath ice streams (Tulaczyk et al. 2001; Clark et al. in press). Our results show that this ‘transport‐limited’ mechanism, in which till transport rates scale with ice velocity and erosion rates with spatial gradients of velocity, is consistent with existing constraints. For instance, our model results predict significantly higher (˜0.6 mm yr‐1) average erosion rates beneath ice‐stream tributaries, which are underlain by deep subglacial troughs, than beneath ice‐stream trunks (˜0.2mm yr‐1), whose subglacial troughs have a significantly smaller relief. We would not obtain this satisfactory result if subglacial erosion was parametrized in the model using the more traditional approach of scaling erosion rates with ice velocity (what we call the ‘production‐limited’ parametrization). Because of the requirement of ice continuity, the magnitude of ice velocity generally increases downstream in polar ice streams, and so do the production‐limited erosion rates. Pending further investigations, we propose that geologic and geomorphic effects of soft‐bedded ice streams should be quantified using some form of a ‘transport‐limited’ parametrization of subglacial erosion rates, e.g. the till‐ploughing mechanism.
Signature of the Baltic Ice Stream on Funen Island, Denmark during the Weichselian glaciation
Authors: JØRGENSEN FLEMMING , PIOTROWSKI JAN A.
Published: July 2010

Ice streams are major dynamic elements of modern ice sheets, and are believed to have significantly influenced the behaviour of past ice sheets. Funen Island exhibits a number of geomorphological and geological features indicative of a Late Weichselian ice stream, a land‐based, terminal branch of the major Baltic Ice Stream that drained the Scandinavian Ice Sheet along the Baltic Sea depression. The ice stream in the study area operated during the Young Baltic Advance. Its track on Funen is characterized by a prominent drumlin field with long, attenuated drumlins consisting of till. The field has an arcuate shape indicating ice‐flow deflection around the island's interior. Beneath the drumlin‐forming till is a major erosional surface with a boulder pavement, the stones of which have heavily faceted and striated upper surfaces. Ploughing marks are found around the boulders. Exact correspondence of striations, till fabric and drumlin orientation indicates a remarkably consistent flow direction during ice streaming. We infer that fast ice flow was facilitated by basal water pressure elevated to the vicinity of the flotation point. The ice movement was by basal sliding and bed deformation under water pressure at the flotation level or slightly below it, respectively. Subglacial channels and eskers post‐dating the drumlins mark a drainage phase that terminated the ice‐stream activity close to the deglaciation. Identification of other ice streams in the Peribaltic area is essential for better understanding the dynamics of the land‐based part of the Scandinavian Ice Sheet during the last glaciation.
Late‐ and postglacial history of the Great Belt, Denmark
Authors: BENNIKE OLE , JENSEN JØRN BO , LEMKE WOLFRAM , KUIJPERS ANTOON , LOMHOLT STEEN
Published: July 2010

On the basis of shallow seismic records, vibrocoring, macrofossil analyses and AMS radiocarbon‐dating, five stratigraphical units have been distinguished from the deepest parts of the central Great Belt (Storebælt) in southern Scandinavia. Widespread glacial deposits are followed by two lateglacial units confined to deeply incised channels and separated by an erosional boundary. Lateglacial Unit I dates from the time interval from the last deglaciation to the Allerød; lateglacial Unit II is of Younger Dryas age. Early Holocene deposits show a development from river deposits and lake‐shore deposits to large lake deposits, corresponding to a rising shore level. Lake deposits are found up to 20 m below the sea floor, and the lake extended over some 200–300 km2. The early Holocene freshwater deposits are dated to the time interval c. 10900 to c. 8800 cal. yr BP and the oldest shells of marine molluscs from the Great Belt are dated to c. 8100 cal. yr BP.
Styles of ice‐marginal deformation at Hagafellsjökull‐Eystri, Iceland during the 1998/99 winter‐spring surge
Authors: BENNETT MATTHEW R. , HUDDART DAVID , WALLER RICHARD I. , MIDGLEY NICHOLAS G. , GONZALEZ SILVIA , TOMIO ALEXANDRE
Published: July 2010

This paper describes the internal architecture of a push moraine formed by a winter‐spring surge of Hagafellsjökull‐Eystri (Iceland) in 1998/99. The sedimentary architecture of this push moraine consists of a multilayered slab of glaciofluvial sediments with a monoclinal structure that has been displaced laterally by the advancing ice margin. The crest and ice‐distal face of the moraine consist of subhorizontal sediment sheets, while the ice‐proximal face dips steeply (45° to 90°) towards the ice margin. The core of the moraine consists of frozen sediment and thin slabs of glacier ice are embedded in its proximal face. The sediment slabs are characterized by both brittle and ductile styles of deformation. We argue that the observed variation in deformation style is dependent on whether the glacial foreland was frozen or unfrozen at the time of displacement. Frozen foreland would behave in a brittle fashion, while unfrozen foreland is likely to have deformed in a more ductile manner. The associated spatial variations in the degree of foreland freezing could be explained by variation in ice‐marginal snow cover. We conclude that the thermal regime of the foreland, and the timing of the ice advance, is of importance to the style of internal deformation found within ice‐marginal push moraines.
ESR/OSL ages of long‐debated subtill fossil‐bearing marine deposits from the southern Kola Peninsula: stratigraphic implications
Authors: MOLODKOV ANATOLY , YEVZEROV VLADIMIR
Published: July 2010

The occurrence of sandy clay deposited in a warm marine environment just below the till of the last glaciation has created controversy about its age and stratigraphic position in the sedimentary basin of the Kola Peninsula. Data on marine microfauna, diatoms, malacofauna and pollen composition indicate that during the period when the sandy clay was deposited the climate was similar or even warmer than at present. According to14C dates, sedimentation of the sandy clay occurred around 40 ka BP. Based on these data, some researchers have attributed these marine deposits to the third Late Pleistocene Belomorian (sensuLavrova 1960) interglacial transgression. At the same time there are geological indications suggesting re‐deposition of these subtill sediments. To solve this problem we have reinvestigated the subtill interglacial marine deposits from the Varzuga section (˜66.4° N and 36.6° E). Four different marine shell species and enclosing sandy clay sediments taken from the subtill marine unit of the section were dated by the electron spin resonance (ESR) and optically‐stimulated luminescence (OSL) methods at about 103 and 104 ka, respectively. The results indicate that the subtill marine deposits belong to the first Late Pleistocene Boreal transgression that, according to our previous studies of the marginal areas of the Eurasian North, has occurred in the time interval from approximately 145 to 70 ka BP.
Holocene chemical weathering and climatic oscillations in north China: evidence from lacustrine sediments
Authors: JIN ZHANGDONG , WU JINGLU , CAO JUNJI , WANG SUMIN , SHEN JI , GAO NANHUA , ZOU CHENJUAN
Published: July 2010

Holocene lacustrine sediments from two isolated lakes in north China are investigated. Based on palaeoclimatic significance of independent proxies in lake sediments, Holocene chemical weathering, and hence climate change, has been reconstructed for dated sediment cores from Daihai Lake and Aibi Lake. During early to mid‐Holocene, higher weathering intensity occurred in the Daihai catchment under warm and humid climate conditions, and this reached a maximum at ˜5 kyr BP. However, synchronous proxy shifts from the two widely separated, isolated lake sediments indicate that there was a cool climate event during the early to mid‐Holocene transition. This is characterized by reduced weathering in each catchment, low δ13 C and δ18O of authigenic carbonate, and by lake level fluctuations. These might correspond to a global cooling signal identified in lakes, oceans, mollusc sequences, and polar ice cores, typically centred between ˜8.0 and 8.5 kyr BP. Dry conditions were experienced in Greenland, the North Atlantic and surrounding regions, and in broad monsoonal regions including Daihai at this time. However, recent extensive evidences as well as our data from the Aibi Lake sediments show that cool but wet conditions occurred in the central Eurasian continent at this time. After ˜2.5 kyr BP, a significant shift of independent sediment proxies indicates the beginning of the Neoglaciation with a higher frequency of fluctuations, including both the Medieval Warm Period (MWP) and the Little Ice Age (LIA). Our continental records provide new evidence of the Holocene climate variability with global significance and highlight the different spatial nature of the response to oscillations associated with different climate patterns.
River Warren boulders, Minnesota, USA: catastrophic paleoflow indicators in the southern spillway of glacial Lake Agassiz
Authors: FISHER TIMOTHY G.
Published: July 2010

Boulders resting on meltwater‐sculpted and striated‐granite bedrock near the head of the southern outlet spillway of glacial Lake Agassiz are used to generate paleodischarge calculations. The rounded nature of many boulders suggests fluvial transport and a corestone origin. The distribution of boulders in clusters and linear trains records the interaction of clasts during transport and deposition. The geomorphology of the spillway with streamlined erosional remnant hills is characteristic of other large flood spillways. Using the Manning equation and a variety of empirical equations to determine paleovelocity, preferred discharges between 0.364 and 0.102 Sv are calculated. These discharges agree well with flood discharges using modeling methodologies, and most likely represent ephemeral and catastrophic flood events linked to either episodic incision at the outlet or the result of rapid inputs of meltwater to Lake Agassiz.
Evaluating Younger Dryas glacier reconstructions in part of the western Scottish Highlands: a combined empirical and theoretical approach
Authors: GOLLEDGE NICHOLAS R. , HUBBARD ALUN
Published: July 2010

Current understanding of the Younger Dryas (Loch Lomond Stadial) ice cap in Scotland is dominated by reconstructions derived solely from field evidence. We use an area in the western Scottish Highlands to evaluate three examples of this approach by comparing the proposed glacier reconstructions with new empirical data and the predictions of a high‐resolution numerical model. Particular emphasis is placed on accurately determining the maximum surface altitude attained by the ice cap, dominant palaeo‐iceflow directions and the style of ice‐cap recession. By combining new geomorphological and sedimentological data with model predictions, we present a revised interpretation of the build‐up and decay of Loch Lomond Stadial ice in the study area—one that suggests a maximum ice‐surface altitude of c. 900 m a.s.l., east and southeastward iceflow and active recession of a dynamic margin. Good agreement between the new field‐based interpretation and the predictions of the numerical model validates the latter and by implication extends confidence in its veracity beyond the study area.
Metamorphic history of a syn‐convergent orogen‐parallel detachment: The South Tibetan detachment system, Bhutan Himalaya
Authors: KELLETT D. A. , GRUJIC D. , WARREN C. , COTTLE J. , JAMIESON R. , TENZIN T.
Published: July 2010

The South Tibetan detachment system (STDS) in the Himalayan orogen is an example of normal‐sense displacement on an orogen‐parallel shear zone during lithospheric contraction. Here, in situ monazite U(–Th)–Pb geochronology is combined with metamorphic pressure and temperature estimates to constrain pressure–temperature–time (P–T–t) paths for both the hangingwall and footwall rocks of a Miocene ductile component of the STDS (outer STDS) now exposed in the eastern Himalaya. The outer STDS is located south of a younger, ductile/brittle component of the STDS (inner STDS), and is characterized by structurally upward decreasing metamorphic grade corresponding to a transition from sillimanite‐bearing Greater Himalayan sequence rocks in the footwall with garnet that preserves diffusive chemical zoning to staurolite‐bearing Chekha Group rocks in the hangingwall, with garnet that records prograde chemical zoning. Monazite ages indicate that prograde garnet growth in the footwall occurred prior to partial melting at 22.6 ± 0.4 Ma, and that peak temperatures were reached following c. 20.5 Ma. In contrast, peak temperatures were reached in the Chekha Group hangingwall by c. 22 Ma. Normal‐sense (top‐to‐the‐north) shearing in both the hangingwall and footwall followed peak metamorphism from c. 23 Ma until at least c. 16 Ma. Retrograde P–T–t paths are compatible with modelled P–T–t paths for an outer STDS analogue that is isolated from the inner STDS by intervening extrusion of a dome of mid‐crustal material.
Implantation of the Total Artificial Heart by Lateral Thoracotomy
Authors: Olsen D. B. , Fukumasu H. , Kolff J. , Nakagaki M. , Finch L. R. , Kolff W. J.
Published: July 2010

Progress in the techniques for surgical implantation of the artificial heart has progressed in parallel with the technology and design of the prosthesis. In the author's first experience with total artificial heart (TAH) implantation (1968) a trans‐sternal split was used opening the sixth intercostal space on the right side across the sternum to the left space. This obviously was not the optimum approach but the complexity, design and size of the prosthesis required maximum exposure of the atria and great vessels. Subsequently the mid‐sternal split incision was used. The Dacron fibril* coated silicone rubber 8 cm Kwan‐Gett ventricles implanted by the mid‐sternal split sustained a calf for 14 days in 1972. A calf with the improved Jarvik 3 ventricles fabricated with the same material and implanted via mid‐sternal split survived 19 days in early 1973. The surgical techniques for lateral (right) thoracotomy were adopted in this laboratory in 1973. These techniques were applicable only when the prostheses fit better in the chest. This procedure has been adopted by other laboratories replacing the natural heart of the calf with a TAH.

This report describes in detail the stepwise procedure for implantation of the total artificial heart by a lateral thoracotomy in the calf.
Sorbent Regeneration of Ultrafiltrate as a Long‐Term Treatment of End‐Stage Renal Failure
Authors: Shaldon S. , Beau M. C. , Claret G. , Deschodt G. , Mion H. , Oules R. , Ramperez P. , Mion C.
Published: July 2010

A sorbent system (Redy® D 11 cartridge) capable of on‐line regeneration of ultrafiltrate during hemofiltration (Amicon 0.5 m2) has been developed and applied on a 3 × 4 hr/week schedule to three patients with end‐stage renal failure previously treated for up to six months with hemodialysis. Total experience, to date, is sixteen patient months (three to seven months). Tolerance to fluid removal improved with the new system. Patient well‐being and rehabilitation have been maintained. The system offers the potential of hemofiltration without sterile replacement fluid or expensive fluid‐balancing machines.
Adsorptive Capacities of Hemoperfusion Devices in Clinical Use
Authors: Hampel Gerhardt , Widdop Brian , Goulding Roy
Published: July 2010

Five different hemoperfusion devices have been used in the treatment of patients intoxicated with barbiturates. The changes in drug clearance values which occurred during hemoperfusion varied according to the device used. Even after very long periods of hemoperfusion, however, drug clearance values never fell to zero. Using data collected from comparable cases, it has been shown that the rate of uptake of drug from the blood is independent of the amount of adsorbent in the columns, those containing 100 gm charcoal having the same efficiency as the conventional 300 gm. The prime factor which determines the rate of drug uptake has been shown to be the arterial plasma drug concentrations. Other factors, such as the deposition of cellular debris and proteins as hemoperfusion progresses, are also thought to influence the efficiency of drug removal.
Influence of Hemoperfusion on the Concentrations of Calcitonin, Testosterone and Cortisol in Blood Plasma
Authors: Kokot Franciszek , Nieszporek Teresa
Published: July 2010

The influence of hemoperfusion with a cellulose‐acetate‐coated charcoal column (Adsorbao 300‐C, Gambro, Lund, Sweden) on plasma concentrations of calcitonin, testosterone and cortisol was studied in five psoriatic patients during 12 treatment periods.

Calcitonin, testosterone and cortisol were effectively removed from blood plasma by the charcoal column with average plasma clearances of 34.0,14.5 and 27.6 ml/min, respectively, at 30 minutes of hemoperfusion, and 4.9, 15.4 and 24.4 ml/min, respectively, at 180 minutes of hemoperfusion. After three hours of hemoperfusion, significant decreases of testosterone and cortisol were found in peripheral venous blood, while calcitonin fell insignificantly. It remains to be elucidated whether long‐term use of hemoperfusion would require a detailed control of possible effects on the endocrine status of patients.
Elimination of Low Molecular Weight Proteins During Hemofiltration
Authors: Röckel A. , Gilge U. , Liewald A. , Heidland A.
Published: July 2010

In patients on regular dialysis treatment, uremic symptoms (anemia, osteopathy, myopathy, neuropathy, and disorders of carbohydrate, fat, and protein metabolism) may be partly due to an accumulation of low molecular weight (MW) proteins (10,000 to 60,000 daltons). We tested this hypothesis using membranes with a higher permeability than conventional Cuprophan membranes. The primary aim of the study was to test the cutoff of various hemofilters (Cuprophan [Highflux], polyamide [FH 20], cellulose acetate [Duof lux], and polyacry‐lonitrile [Hospal RP 7 + 8 and Asahi PAN]) under in vivo conditions. In addition the effects of hemofiltration on plasma low molecular weight protein concentrations, polyneuropathy, and autonomic insufficiency were also tested in a long‐term (six‐month) study using the membrane with the highest cutoff and most constant sieving coefficient, i.e., Highflux.

Low MW proteins with a defined MW were used as marker substances. Sieving coefficients of β2‐microglobulin, lysozyme, retinol‐binding protein, α1‐glycoprotein, α1‐antitrypsin, prealbumin, albumin, and transferrin were determined during a four‐hour hemofiltration (20 L ultrafiltrate). Proteins were analyzed using an immunodiffusion technique. In the long‐term study, motor nerve conduction velocity, the Schellong test, and Valsalva maneuver were tested prior to and three and six months after hemofiltration therapy.

Highflux, Duoflux, and FH 202 membranes were permeable to proteins with molecular weights up to 15,000 daltons, and the Highflux module had the most constant sieving coefficient during hemofiltration. In the six‐month hemofiltration study with the Highflux filter, plasma β2‐microglobulin and lysozyme decreased significantly as expected. Parameters of polyneuropathy and autonomic insufficiency were slightly improved.
Anal and Urinary Control Device
Authors: Numanoĝlu Ihsan
Published: July 2010

Abstract: Anal and urinary incontinence remains a major problem in spite of many efforts to correct it in the past. The present study describes the development of a new device for controlling anal and urinary incontinence and its successful use in 20 patients. The device is applied to the anorectal area in a noninvasive manner. It provides continence and, upon removal, allows normal bowel movement and urination. The cleaned device is then reapplied. The anorectal area tolerates the device well and no complications have been observed.
Coronary Vascular Actions of Stroma‐Free Hemoglobin Preparations
Authors: Biro G. P. , Taichman G. C. , Lada B. , Keon W. J. , Rosen A. L. , Sehgal L. R.
Published: July 2010

Abstract:The left anterior descending coronary artery was cannulated in anesthetized, open‐chest dogs for use as a coronary test bed to assess the coronary vascular actions of oxygenated, unmodified and pyridoxylated, partially cross‐linked (polymerized), stroma‐free hemoglobin solutions (SFHS). The actions of these SFHSs were assessed in this test bed, by comparison with perfusion with whole blood. Unmodified SFHS caused significant vasoconstriction, whereas pyridoxylated, partially polymerized SFHS did not do so. The existing coronary flow during perfusion with either SFHS preparation, under basal conditions, did not increase during intracor‐onary infusion of adenosine. Coronary flow‐autoregula‐tion was also altered during perfusion with either SFHS, because the “normal” reactive hyperemia response, observed in the control experiments, was not seen. These findings suggest that both unmodified and pyridoxylated cross‐linked (70% polymers) hemoglobin preparations possess some vascular activity when tested in the canine coronary circulation.
Kinetics of cis‐Dichlorodiammine Platinum (II) during Plasmapheresis
Authors: Hosokawa Shinichi , Mizuno Hiroshi , Abe Ryuzi , Yoshida Osamu
Published: July 2010

Abstract: The pharmacokinetics of cw‐dichlorodiam‐mineplatinum (II) (cisplatin) during double filtration plasmapheresis (PP) have been studied in ten patients who received the drug as a 30 min infusion. The patients receiving the drug exhibited biphase clearance of total platinum with a rapid initial phase (40 min) and a prolonged second phase (1–24 h). Free (ultrafiltrable) cisplatin was readily detectable and the clearance curve of free cisplatin was biphasic, with a short initial phase (1 h) and a long second phase (1–24 h). In conclusion, the loss of both total cisplatin and free cisplatin in serum were not found during plasmapheresis.
A Newly Designed Flow‐Regulating Device in Shunt Therapy of Hydrocephalus
Authors: Hashimoto Shigehiro , Kawano Nobuyuki
Published: July 2010

Abstract: A new flow‐regulating device for shunting in hydrocephalus was designed to limit an excess flow by a pressure‐head between the cerebral ventricle and the abdominal cavity in a standing position. The device has two diaphragm valves connected to each other by two lines: one is a shunting line to transfer cerebrospinal fluid and the other is a control line filled with a control fluid with a higher density than cerebrospinal fluid. The performance of the model device with a natural rubber sheet diaphragm was tested in a mock system, using glycerol for the control fluid and water for the transfer fluid in vitro. Results show that device decreases the excess flow when the pressure‐head between two valves exceeds 35 cm.
Heparin‐Coated Equipment Reduces Complement Activation during Cardiopulmonary Bypass in the Pig
Authors: Nilsson L. , Storm K. E. , Thelin S. , Bagge L. , Hultman J. , Thorelius J. , Nilsson U.
Published: July 2010

Abstract: Complement activation was studied during cardiopulmonary bypass (CPB) in the pig. One group of animals was perfused for 2 h using a standard extracorporeal circuit including a hollow fiber membrane oxygenator with full systemic heparinization. Another group was treated in the same way, except that bypass was performed through a heparin‐coated CPB circuit (Carmeda Bio‐Active Surface, CBAS) and systemic heparinization was reduced by 75%. It was found that complement activation during CPB, measured as changes in the ratio C3d/C3, was significantly less in the CBAS group, most probably reflecting a better biocompatibility.
Total Artificial Heart Without Valves: Principles of Design and Implantation Technique
Authors: Konstantinov B. A. , Dzemeshkevich S. L. , Egorov T. A. , Pilyavin M. A. , Guskov I. A.
Published: July 2010

Abstract: A total artificial heart (TAH) without valves is a TAH of a new design. The entry and exit are combined in one opening. The excision of the biologic ventricles is below the atrioventricular groove, while the outlet and position of the right and left ventricles are preserved. The aortic and pulmonary valves have been left intact. Bioprostheses BAKS are implanted into the mitral and tri cuspidal positions. Initial experiments hold much promise: the absence of artificial valves decreases the risk of thromboemboly; the natural heart basis remains intact, which facilitates the subsequent donor heart transplantation; and the work of the new TAH is practically noiseless.
Effect of Extracorporeal Membrane Oxygenation on Leukocyte Function in Neonates
Authors: Hocker James R. , Wellhausen Samuel R. , Ward Richard A. , Simpson Pippa M. , Cook Larry N.
Published: July 2010

Abstract: The impact of extracorporeal membrane oxygenation (ECMO) on neonatal leukocyte content and function was examined in six patients. Patients were treated with ECMO for a mean of 134 h (range 44–246 h). Absolute neutrophil counts decreased from 14679 ± 2291/ mm3 to 7791 ± 1672/mm3 after 2 h of ECMO. However, neutrophil phagocytosis and oxidative burst remained unchanged during the first 48 h of bypass. Monocyte counts also decreased during bypass, and at times were undetectable in 50% of patients. Monocyte HLA–DR content was decreased compared to normal cord blood prior to initiation of ECMO, and remained low throughout ECMO. However, the content increased significantly after termination of bypass. Plasma C3a levels increased transiently, paralleled by an increase in neutrophil CR3 expression. While moribund infants had some impairment of host defenses prior to ECMO, there was no further impact of ECMO per se on the parameters measured, other than transient complement activation and decreased monocyte counts.
Studies of the Development of Optical Fiber Sensors for Biochemical Analysis
Authors: Takai N. , Sakuma I. , Fukui Y. , Kaneko A. , Fujie T. , Taguchi K. , Nagaoka S.
Published: July 2010

Abstract:An optical fiber sensor utilizing Thymol blue and an ion–exchange resin complex in a cellulose acetate membrane was developed. By monitoring several different chromophores of Thymol blue, the sensor could measure the pH of the solution from 1.0 to 12.0 with good reproducibility. An optical fiber glucose sensor utilizing a cellulose acetate membrane containing glucose oxidase, 2,7–diaminofluorene dihydrochloride, and sodiumN–(3–sulfopropyl)–3,3′,5,5′–tetramethylbenzidine was developed. Reflectance changes at 580 nm were large enough to trace changes in glucose concentration in physiological saline solution. Key Words: Optical fiber sensor.
Investigation of Parameter Estimator and Adaptive Controller for Assist Pump by Computer Simulation
Authors: Shimooka Toshiyuki , Mitamura Yoshinori , Yuhta Toshio
Published: July 2010

Abstract: The multioutput adaptive controller of a left ventricular assist device (LVAD) was studied by computer simulation. The controller regulated two outputs–mean aortic pressure (mAoP) and mean atrial pressure (mLAP)–by regulating vacuum pressure (input). The autoregressive models were used to describe the circulatory system. The parameters of the models were estimated by the recursive least squares method. Based on the autoregressive models, the vacuum pressure minimizing a performance index was searched. The index used was the weighted summation of the square errors. Responses of the adaptive controller were simulated when the contractility of the left ventricle was decreased at various rates and the peripheral resistance was changed. Both the mAoP and mLAP were controlled to their predicted values in the steady state. The steady–state errors of the mAoP were less than a few mm Hg, and those of the mLAP were lower than 1 mm Hg. Consequently, the estimated parameters can be regarded as true parameters, and the adaptive controller has the potential to control more than two outputs. The multioutput adaptive controller studied is useful in controlling the LVAD according to the change in circulatory condition.
Bioartificial Organs
Authors: Galletti Pierre M.
Published: July 2010

Abstract. Bioartificial organs combine the physical aspects of implantable prostheses with the biological advantages of organ transplantation. Enclosing live cells in a permselective, synthetic envelope avoids rejection by an irnmunoincompatible host while the geometric limitation of the closed polymer capsule prevents overgrowth of the transplanted material. As a tenet bioartificial organs widen the range of therapeutics based on the biological activity of cell transplants and open an alternative path to gene therapy.
Improved Function of Microencapsulated Hepatocytes in a Hybrid Bioartificial Liver Support System
Authors: Dixit Vivek , Arthur Marika , Reinhardt Renate , Gitnick Gary
Published: July 2010

Abstract: Conventional methods of microencapsulating isolated hepatocytes with Type I collagen matrix have provided metabolic liver support in experimental animal models of acute liverfailure and congenital metabolic liver disease. We compared the biological function of transplanted microencapsulated hepatocytes cultured on standard Type I collagen (Vitrogen) and a commercially available liver basement‐membrane‐like extract from a mouse sarcoma (Matrigel). Isolated hepatocytes were micro‐encapsulated with Matrigel and Vitrogen within an alginate‐poly‐r‐lysine composite membrane. Isolated encapsulated hepatocytes (IEH) were transplanted intra‐peritoneally into homozygous Gunn rats that exhibit congenital hyperhilirubinemia. Control Gunn rats received empty or no microcapsules. Total serum bilirubin and conjugated bilirubin in bile were measured at weekly intervals for one month. Significant (p < 0.01) decreases in total serum bilirubin were observed in all IEH transplanted animals. No such decrease was seen in control animals. Gunn rats that received Matrigel had significantly (p < 0.05) lower serum bilirubin values and significantly (p < 0.05) higher conjugated bilirubin in bile than those that received Vitrogen. We conclude that hepatocytes microencapsulated with Matrigel functioned better than those with Vitrogen. This improved in vivo biological response underscores the importance of using the appropriate cell attachment substratum to enhance the function of a hybrid bioartificial liver support system based on transplanted hepatocytes.
Bovine Pericardium Versus Porcine Aortic Valve: Comparison of Tissue Biological Properties as Prosthetic Valves
Authors: Liao Kangxiong , Seifter Eli , Hoffman Darryl , Yellin Edward L. , Frater Robert W.M.
Published: July 2010

Abstract: The choice of a bioprosthetic valve substitute remains controversial with the major concern being primary tissue failure after implantation. We compared biological properties of the two most frequently used bioprosthetic valve materials, bovine pericardium and porcine aortic valve, before and 90 days after subcutaneous implantation in rats. Before implantation, tissue collagen and water content were measured in nine pieces of bovine pericardium and porcine valves, each fixed in 0.625% glu‐taraldehyde; calcium, tissue collagen, and water content were measured in another nine pieces of the same tissues after 90 days' implantation. Bovine pericardium had higher collagen content than that of porcine valve (hy‐droxyproline, 7.98 = 0.05* vs. 4.56 = 0.02 γg/mg, dry weight) but lesser water content (72.16 = 3.22%* vs. 87.36 = 1.62%) before implantation (*p < 0.001, mean = SD, t test); after implantation, bovine pericardium still maintained higher collagen content (hydroxyproline, 4.89 = 0.04* vs. 2.61 ± 0.06 γg/mg, dry weight) but contained the same amount of water (60.24 ± 5.08% vs. 61.43 ± 9.00%) and calcium (214.43 ± 34.34 vs. 199.33 ± 53.44 γg/mg, dry weight) (*p < 0.001, mean ± SD, t test). We conclude that bovine pericardium has superior intrinsic biological properties for prosthetic valve manufacture. With proper integration of properties and design it will in some applications be superior to the porcine aortic valve.
Transposed Basilic Vein‐Brachial Arteriovenous Fistula: An Alternative Vascular Access for Hemodialysis
Authors: Hatjibaloglou A. , Grekas D. , Saratzis N. , Megalopoulos A. , Moros I. , Kiskinis D. , Dalainas V.
Published: July 2010

Abstract: Twenty‐five brachial‐basilic arteriovenous (AV) fistulas with transposed basilic vein for alternative vascular access were created in 22 chronic hemodialysis patients. This surgical procedure was performed under brachial block or general anesthesia. After a longitudinal skin incision that was made in the inner side of the arm, the basilic vein was exposed, transposed subcutaneously, and anastomosed end‐to‐side to the brachial artery. The follow‐up was between 7 and 24 months. Early complications were hemorrhage, thrombosis, steal syndrome, and swelling of the arm. Among the late complications were failure of the fistula because of thrombosis and multiple stenosis at the site of venipuncture. The accumulated one‐year patency rate of fistulas was 81%. The complications of high‐output cardiac failure or local infection were not seen in our study. On the basis of our results, the brachial‐basilic AV fistula with transposed basilic vein is a useful and safe second‐ or third‐choice vascular procedure for hemodialysis patients, in particular for women without good quality of vessels.
Improved Liver Function Following Treatment with an Extracorporeal Liver Assist Device
Authors: Sussman Norman L. , Kelly James H.
Published: July 2010

Abstract: A 68‐year‐old woman with fulminant hepatic failure of unknown etiology was treated with a bioartificial liver assist device. Prior to treatment, she had a number of clinical and laboratory features that suggested a hopeless outcome. Treatment was associated with a dramatic change in her mental status, and her clinical picture improved progressively during 6 days of continuous therapy. Evidence of recovery of native liver function allowed the discontinuation of treatment, and she continued to improve for a further 3½ days before her demise from septic shock. We propose that a metabolically active liver assist device is a logical and practical method for treating the critical phase of fulminant hepatic failure.
Percutaneous Cardiopulmonary Support as the Second Generation of Venoarterial Bypass: Current Status and Future Direction
Authors: Nishida Hiroshi , Shibuya Mitsuhiro , Kitamura Masaya , Hachida Mitsuhiro , Aomi Shigeyuki , Endo Masahiro , Hashimoto Akimasa , Koyanagi Hitoshi
Published: July 2010

Abstract: We have developed a new percutaneous cardiopulmonary support (PCPS) system in cooperation with Terumo Corporation, called the Emergency Bypass System (EBS). This preassembled system is unique in terms of its small priming volume (470 cc), fully automatic priming function, originally developed membrane oxygenator, and Capiox straight path centrifugal pump. The priming process takes only 5 min. We have used this system in 4 patients (all were male; mean age 56 years, range 35–73 years). The duration of assist ranged from 15 min to 210 h. Maximum bypass flow ranged from 2.2 to 3.6 L/min, systemic circulation was very well maintained, and urinary output was acceptable. Although the centrifugal pump was in good working condition, we had to change the oxygenator because of serum leakage 36 to 48 h after initiation of the assist. One patient was weaned from the PCPS, but died of brain death. The other patients could not be weaned from the PCPS. The cause of death in these patients was irreversible myocardial damage. Disseminated intravascular coagulopathy triggered by surgical trauma related to various procedures developed in 2 patients during assist and was the cause of cessation of the assist. Problems to be ratified and future directions in the EBS and PCPS were earlier introduction through the establishment of clear indications and endpoint, heparin coating, improvement in durability of the oxygenator, and cost.
Left and Right Pump Output Control in One‐Piece Electromechanical Total Artificial Heart
Authors: Takatani Setsuo , Shiono Motomi , Sasaki Tatsuya , Orime Yukihiko , Sakuma Ichiro , Noon George , Nosé Yukihiko , DeBakey Michael
Published: July 2010

Abstract: Left master alternate (LMA) ejection control based on the left pump fill method was implemented for a one‐piece electromechanical total artificial heart (TAH). The TAH consists of left and right pusher‐plate‐type blood pumps sandwiching a compact electromechanical actuator comprising a direct current (DC) brushless motor and a planetary roller screw. The motor rotation is controlled on the basis of the roller‐screw position as detected by a Hall effect sensor and a commutation pulse‐counting method. Since the pusher‐plate shaft and roller screw are decoupled during filling, both pumps fill passively with the right and left atrial pressure. To obtain response to the right atrial pressure change in the LMA mode, the left fill trigger level as detected by a Hall effect position sensor is adjusted to operate the pump at a higher rate and to drive the right pump at 85–90% of the full stroke level. The invitro evaluation demonstrated that this method can respond to right atrial pressure changes provided that the right pump is operated at less than the full stroke level. When the preload is high and the right pump goes into full stroke operation, the left eject level can be decreased to run the pump at a higher rate and to transfer more blood from the right to the left. In the in vivo evaluation, which lasted 1 week in a 95 kg calf, the left and right atrial pressures were kept within physiological ranges. The LMA mode triggered by the left pump fill can protect the lungs and can also respond to venous return change and therefore is a reliable control method for a one‐piece to‐tally implantable TAH system.