bluuebunny/crossref_metadata_2025 huggingface dataset:
ROTATING RELATIVISTIC THIN DISKS AS SOURCES OF CHARGED AND MAGNETIZED KERR–NUT SPACE–TIMES
Authors: GARCÍA-REYES GONZALO , GONZÁLEZ GUILLERMO A.
Published: September 2009

A family of models of counterrotating and rotating relativistic thin disks of infinite extension based on a charged and magnetized Kerr–NUT metric are constructed using the well-known "displace, cut and reflect" method extended to solutions to vacuum Einstein–Maxwell equations. The metric considered has as limiting cases a charged and magnetized Taub–NUT solution and the well-known Kerr–Newman solutions. We show that for Kerr–Newman fields the eigenvalues of the energy–momentum tensor of the disk are for all the values of the parameters' real quantities so that these disks do not present heat flow in any case, whereas for charged and magnetized Kerr–NUT and Taub–NUT fields we always find regions with heat flow. We also find a general constraint on the counterrotating tangential velocities needed to cast the surface energy–momentum tensor of the disk as the superposition of two counterrotating charged dust fluids. We show that, in general, it is not possible to take the two counterrotating fluids as circulating along electrogeodesics or take the two counterrotating tangential velocities as equal and opposite.
PRICING OF TRAFFIC LIGHT OPTIONS AND OTHER HYBRID PRODUCTS
Authors: KOKHOLM THOMAS
Published: September 2009

This paper considers derivatives with payoffs that depend on a stock index and underlying LIBOR rates. A traffic light option pricing formula is derived under lognormality assumptions on the underlying processes. The traffic light option is aimed at the Danish life and pension sector to help companies stay solvent in the traffic light stress test system introduced by the Danish Financial Supervisory Authorities in 2001. Similar systems are now being implemented in several other European countries. A pricing approach for general payoffs is presented and illustrated with simulation via the pricing of a hybrid derivative known as the EUR Sage Note. The approach can be used to price many existing structured products.
LEARNING INDIRECT ACTIONS IN COMPLEX DOMAINS: ACTION SUGGESTIONS FOR AIR TRAFFIC CONTROL
Authors: AGOGINO ADRIAN , TUMER KAGAN
Published: September 2009

Providing intelligent algorithms to manage the ever-increasing flow of air traffic is critical to the efficiency and economic viability of air transportation systems. Yet, current automated solutions leave existing human controllers "out of the loop" rendering the potential solutions both technically dangerous (e.g. inability to react to suddenly developing conditions) and politically charged (e.g. role of air traffic controllers in a fully automated system). Instead, this paper outlines a distributed agent-based solution where agents provide suggestions to human controllers. Though conceptually pleasing, this approach introduces two critical research issues. First, the agent actions are now filtered through interactions with other agents, human controllers and the environment before leading to a system state. This indirect action-to-effect process creates a complex learning problem. Second, even in the best case, not all air traffic controllers will be willing or able to follow the agents' suggestions. This partial participation effect will require the system to be robust to the number of controllers that follow the agent suggestions. In this paper, we present an agent reward structure that allows agents to learn good actions in this indirect environment, and explore the ability of those suggestion agents to achieve good system level performance. We present a series of experiments based on real historical air traffic data combined with simulation of air traffic flow around the New York city area. Results show that the agents can improve system-wide performance by up to 20% over that of human controllers alone, and that these results degrade gracefully when the number of human controllers that follow the agents' suggestions declines.
LEARNING FROM ACTIONS NOT TAKEN IN MULTIAGENT SYSTEMS
Authors: TUMER KAGAN , KHANI NEWSHA
Published: September 2009

In large cooperative multiagent systems, coordinating the actions of the agents is critical to the overall system achieving its intended goal. Even when the agents aim to cooperate, ensuring that the agent actions lead to good system level behavior becomes increasingly difficult as systems become larger. One of the fundamental difficulties in such multiagent systems is the slow learning process where an agent not only needs to learn how to behave in a complex environment, but also needs to account for the actions of other learning agents. In this paper, we present a multiagent learning approach that significantly improves the learning speed in multiagent systems by allowing an agent to update its estimate of the rewards (e.g. value function in reinforcement learning) for all its available actions, not just the action that was taken. This approach is based on an agent estimating the counterfactual reward it would have received had it taken a particular action. Our results show that the rewards on such "actions not taken" are beneficial early in training, particularly when only particular "key" actions are used. We then present results where agent teams are leveraged to estimate those rewards. Finally, we show that the improved learning speed is critical in dynamic environments where fast learning is critical to tracking the underlying processes.
MULTISCALED CROSS-CORRELATION DYNAMICS IN FINANCIAL TIME-SERIES
Authors: CONLON T. , RUSKIN H. J. , CRANE M.
Published: September 2009

The cross-correlation matrix between equities comprises multiple interactions between traders with varying strategies and time horizons. In this paper, we use the Maximum Overlap Discrete Wavelet Transform to calculate correlation matrices over different time–scales and then explore the eigenvalue spectrum over sliding time-windows. The dynamics of the eigenvalue spectrum at different times and scales provides insight into the interactions between the numerous constituents involved.

Eigenvalue dynamics are examined for both medium, and high-frequency equity returns, with the associated correlation structure shown to be dependent on both time and scale. Additionally, the Epps effect is established using this multivariate method and analyzed at longer scales than previously studied. A partition of the eigenvalue time-series demonstrates, at very short scales, the emergence of negative returns when the largest eigenvalue is greatest. Finally, a portfolio optimization shows the importance of time–scale information in the context of risk management.
PROTEIN FOLD CLASSIFICATION WITH GENETIC ALGORITHMS AND FEATURE SELECTION
Authors: CHEN PENG , LIU CHUNMEI , BURGE LEGAND , MAHMOOD MOHAMMAD , SOUTHERLAND WILLIAM , GLOSTER CLAY
Published: September 2009

Protein fold classification is a key step to predicting protein tertiary structures. This paper proposes a novel approach based on genetic algorithms and feature selection to classifying protein folds. Our dataset is divided into a training dataset and a test dataset. Each individual for the genetic algorithms represents a selection function of the feature vectors of the training dataset. A support vector machine is applied to each individual to evaluate the fitness value (fold classification rate) of each individual. The aim of the genetic algorithms is to search for the best individual that produces the highest fold classification rate. The best individual is then applied to the feature vectors of the test dataset and a support vector machine is built to classify protein folds based on selected features. Our experimental results on Ding and Dubchak's benchmark dataset of 27-class folds show that our approach achieves an accuracy of 71.28%, which outperforms current state-of-the-art protein fold predictors.
PREDICTING LOCAL QUALITY OF A SEQUENCE–STRUCTURE ALIGNMENT
Authors: GAO XIN , XU JINBO , LI SHUAI CHENG , LI MING
Published: September 2009

Although protein structure prediction has made great progress in recent years, a protein model derived from automated prediction methods is subject to various errors. As methods for structure prediction develop, a continuing problem is how to evaluate the quality of a protein model, especially to identify some well-predicted regions of the model, so that the structural biology community can benefit from the automated structure prediction. It is also important to identify badly-predicted regions in a model so that some refinement measurements can be applied to it. We present two complementary techniques, FragQA and PosQA, to accurately predict local quality of a sequence–structure (i.e. sequence–template) alignment generated by comparative modeling (i.e. homology modeling and threading). FragQA and PosQA predict local quality from two different perspectives. Different from existing methods, FragQA directly predicts cRMSD between a continuously aligned fragment determined by an alignment and the corresponding fragment in the native structure, while PosQA predicts the quality of an individual aligned position. Both FragQA and PosQA use an SVM (Support Vector Machine) regression method to perform prediction using similar information extracted from a single given alignment. Experimental results demonstrate that FragQA performs well on predicting local fragment quality, and PosQA outperforms two top-notch methods, ProQres and ProQprof. Our results indicate that (1) local quality can be predicted well; (2) local sequence evolutionary information (i.e. sequence similarity) is the major factor in predicting local quality; and (3) structural information such as solvent accessibility and secondary structure helps to improve the prediction performance.
EFFICIENT SIMULATION OF LIGAND–RECEPTOR BINDING PROCESSES USING THE CONFORMATION DYNAMICS APPROACH
Authors: BUJOTZEK ALEXANDER , WEBER MARCUS
Published: September 2009

The understanding of biological ligand–receptor binding processes is relevant for a variety of research topics and assists the rational design of novel drug molecules. Computer simulation can help to advance this understanding, but, due to the high dimensionality of according systems, suffers from the severe computational cost. Based on the framework provided by conformation dynamics and transition state theory, a novel heuristic approach of simulating ligand–receptor binding processes is introduced, which is not dependent on calculating lengthy molecular dynamics trajectories. First, the relevant portion of conformational space is partitioned with meshless methods. Then, each region is sampled separately, using hybrid Monte Carlo. Finally, the dynamical binding process is reconstructed from the static overlaps between the partial densities obtained in the sampling step. The method characterizes the metastable steps of the binding process and can yield the corresponding transition probabilities.
ANALYSIS OF SUBGRADE IN PERMAFROST REGION AND PERMAFROST ALONG QINGHAI-TIBET RAILWAY FOR IMPACT OF CLIMATE WARMING
Authors: JIANJUN GE
Published: September 2009

Through the prediction of climate change on Qinghai-Tibet plateau, the thermal conditions in permafrost region and degenerating range of permafrost are predicted under two different warming conditions with the help of the numerical simulation technique. General design principles of subgrade engineering in permafrost region under climate change are consequently suggested. This paper analyzes and discusses the stability and safety of subgrade engineering in permafrost region under temperature rising and summarizes the effect of climate change on subgrade engineering in permafrost region along Qinghai-Tibet railway.
SAFETY ENHANCEMENT OF URBAN STRUCTURES WITH STRUCTURAL RECOVERABILITY AND CONTROLLABILITY
Authors: WU ZHISHEN , FAHMY MOHAMED F. M. , WU GANG
Published: September 2009

The novel concept presented in this paper is the use of fiber reinforced polymers (FRP) to control the performance of new and existing reinforced concrete (RC) structures during and after moderate to strong earthquakes. This study was conducted in three major steps. First, an overview of the different concepts considered to improve both the pre- and post-earthquake performances of new infrastructures is presented. Second, a mechanical model for FRP-RC structure damage control is defined. Third, based on the proposed definition for controllable structures and using the post-yield stiffness and permanent deformations as seismic performance measures, the results of scaled tests of different structural elements are examined. For virgin beams, strengthening new RC beams or those with initial damage using hybrid FRP are presented, and the results of using wet bonding between FRP and concrete as a new technique for the construction of structures are briefly discussed. In addition, the effectiveness of FRP jacketing in existing non-ductile RC bridge columns with different deficiencies for quick recoverability after an earthquake is scrutinized using a large experimental database. Finally, to achieve a recoverable and more durable structure, the performance of steel bars wound with different types of FRP as reinforcement is highlighted.
Weathering of granite and granitic regolith in Corsica: short-term
10
Be versus long-term thermochronological constraints
Authors: Kuhlemann Joachim , Krumrei Ingrid , Danišík Martin , Borg Klaas van der
Published: September 2009

In situ
10
Be concentrations in granites on Corsica (Mediterranean), exposed to subalpine climate, yield weathering rates of between 9 and 20 mm ka
−1
, when averaged over the last 30–100 ka. Weathering rates rise with increasing precipitation and brittle deformation. Thermal history modelling of apatite fission-track (AFT) data confirms that average denudation rates of 5–20 mm ka
−1
were typical during the Neogene. Short- and long-term denudation rates are in the same range and indicate that a late Neogene global increase in denudation rates has probably not affected geomorphically stable uplifted palaeosurfaces of hilly to low mountainous local relief. A Southwards decrease in short- and long-term denudation rates indicate a linear relationship with decreasing precipitation. Post-glacial downwearing of moraine matrix, as constrained by soil-derived humic etching of dated glacial boulders, yields 40–140 mm ka
−1
, which indicates a poor preservation potential of moraines older than the last glaciation. This weathering rate is of the order of 3 times faster than that found for long-term regolith formation from granites based on of geomorphic evidence.
Post Pan-African thermo-tectonic evolution of the north Mozambican basement and its implication for the Gondwana rifting. Inferences from
40
Ar/
39
Ar hornblende, biotite and titanite fission-track dating
Authors: Daszinnies M. C. , Jacobs J. , Wartho J.-A. , Grantham G. H.
Published: September 2009

This research paper investigates the thermo-tectonic history of the north Mozambican basement subsequent to the Pan-African metamorphism. Six
40
Ar/
39
Ar hornblende, three
40
Ar/
39
Ar biotite and 25 titanite fission-track data place new constraints on the earliest timing of rifting in the central sector of Gondwana, and demonstrate a close linkage between the geometric rift configuration and the ductile metamorphic basement fabrics during the initial dispersal of the supercontinent.

The
40
Ar/
39
Ar hornblende and biotite ages range from
c
. 542 to 456 Ma and from
c
. 448 to 428 Ma, respectively. These data record slow basement cooling after the latest Pan-African metamorphism at rates of
c
. 7–11 °C Ma
−1
between Early and Late Ordovician times. Locally, syn- to post-tectonic granitoid emplacements around 500–450 Ma delayed basement cooling to Late Ordovician–Early Silurian times. The titanite fission-track (TFT) ages fall into two age groups of
c
. 378–327 Ma and
c
. 284–219 Ma. The older TFT ages record very slow cooling from the Late Ordovician–Early Silurian to below 275±25 °C in the Late Devonian–Early Carboniferous at slow rates of less than 1 °C Ma
−1
. This slow cooling is related to decreasing denudation in association with the establishment of pre-Karoo peneplains in central Gondwana. The younger TFT ages record denudation due to rift flank uplift in the context of initial Gondwana disintegration in the Mozambican sector. Corresponding Early–Late Permian crustal extension proceeded obliquely to a NW–SE tensional palaeo-stress field and was associated with a brittle reactivation of easterly trending ductile basement fabrics. In total, up to ≤9–12 km of denudation is deduced from the TFT results since Permo-Carboniferous times.
Combined titanite and apatite fission-track data from Gjelsvikfjella, East Antarctica – another piece of a concealed intracontinental Permo-Triassic Gondwana rift basin?
Authors: Emmel B. , Jacobs J. , Daszinnies M. C.
Published: September 2009

Titanite and apatite fission-track ages from Gjelsvikfjella and the eastern Mühlig–Hofmann Mountains, East Antarctica, range between 516±50 and 323±30 Ma and 366±16 and 186±9 Ma, respectively. The thermochronological data set indicates differential cooling of two tectonic blocks (Hochlinfjellet–Festninga and Risemedet). Inverse modelled time–temperature paths suggest that the Hochlinfjellet–Festninga block cooled at first below 60 °C during the mid-Palaeozoic, whereas the Risemedet block cooled during the earliest Triassic. Differential cooling is most probably related to physical separation along active faults, which is associated with Gondwana-wide intracontinental rifting. This tectonic activity shaped the landscape in the study area along structures running perpendicular to the continental margin of Dronning Maud Land. A rift locus was possibly located along the Penck–Jutul graben west of the study area. In contrast to other parts of Dronning Maud Land, Jurassic magmatism and initial break-up between East Africa and East Antarctica did not influence the apatite FT data. Modelled apatite fission-track data indicate the onset of final cooling since the Early Cretaceous, suggesting post-Cretaceous unroofing of the palaeosurfaces in eastern Dronning Maud Land.
Quantitative constraints on mid- to shallow-crustal processes using the zircon (U–Th)/He thermochronometer
Authors: Dobson Katherine J. , Persano Cristina , Stuart Finlay M.
Published: September 2009

Despite the potential of zircon He thermochronometry for constraining rock thermal histories, it remains less commonly exploited than the apatite He chronometer. In part, this is due to the more challenging analytical techniques required to extract He, U and Th. Here we present a new method for the routine determination of zircon (U–Th)/He ages, and demonstrate how it can be used to constrain thermal histories and to quantify cooling in different tectonic settings. We present zircon (U–Th)/He ages that place a firm upper limit on the extent of denudation-induced cooling (
c
. 3 km) on the SE Australian passive margin; a region where synrift apatite fission-track and apatite (U–Th)/He ages have previously prevented quantitative constraint. We have also used the zircon (U–Th)/He thermochronometer to quantify the cooling of early Tertiary mafic plutons from Skye, Scotland, where the rate and timing of cooling cannot be determined using other thermochronometers.
Abnormal nitric oxide production in aged rat mesenteric arteries is mediated by NAD(P)H oxidase-derived peroxide
Authors: Zhou Xiaosun , Bohlen H. Glenn , Unthank Joseph L. , Miller Steven J.
Published: September 2009

Previous work in our laboratory showed increased basal periarterial nitric oxide (NO) and H2O2 concentrations in the spontaneously hypertensive rat, characterized by oxidant stress, as well as impaired flow-mediated NO production that was corrected by a reduction of periarterial H2O2. Aging is also associated with an increase in vascular reactive oxygen species and results in abnormal vascular function. The current study was designed to assess the role of H2O2 in regulating NO production during vascular aging. In vivo, real-time NO and H2O2 concentrations were measured by microelectrodes in mesenteric arteries of retired breeder (aged; 8–12 mo) and young (2 to 3 mo) Wistar-Kyoto rats under conditions of altered flow. The results in aged rats revealed elevated basal NO (1,611 ± 286 vs. 793 ± 112 nM, P < 0.05) and H2O2 concentrations (16 ± 2 vs. 9 ± 1 μM, P < 0.05) and a flow-mediated increase in H2O2 but not NO production. Pretreatment of aged rats with the antioxidant apocynin lowered both basal H2O2 (8 ± 1 μM) and NO (760 ± 102 nM) to young levels and restored flow-mediated NO production. Similar results were obtained with the NAD(P)H oxidase inhibitor gp91ds-tat. In addition, acute incubation with topical polyethylene-glycolated catalase lowered the baseline NO concentration and restored flow-mediated NO production. Taken together, the data indicate that elevated baseline and suppressed flow-mediated NO production in aged Wistar-Kyoto rats are mediated by NAD(P)H oxidase-derived H2O2.
Unpacking a gel-forming mucin: a view of MUC5B organization after granular release
Authors: Kesimer Mehmet , Makhov Alexander M. , Griffith Jack D. , Verdugo Pedro , Sheehan John K.
Published: September 2009

Gel-forming mucins are the largest complex glycoprotein macromolecules in the body. They form the matrix of gels protecting all the surface epithelia and are secreted as disulfide-bonded polymeric structures. The mechanisms by which they are formed and organized within cells and thereafter released to form mucus gels are not understood. In particular, the initial rate of expansion of the mucins after release from their secretory granules is very rapid (seconds), but no clear mechanism for how it is achieved has emerged. Our major interest is in lung mucins, but most particularly in MUC5B, which is the major gel-forming mucin in mucus, and which provides its major protective matrix. In this study, using OptiPrep density gradient ultracentrifugation, we have isolated a small amount of a stable form of the recently secreted and expanding MUC5B mucin, which accounts for less than 2% of the total mucin present. It has an average mass of ∼150 × 106 Da and size Rg of 150 nm in radius of gyration. In transmission electron microscopy, this compact mucin has maintained a circular structure that is characterized by flexible chains connected around protein-rich nodes as determined by their ability to bind colloidal gold. The appearance indicates that the assembled mucins in a single granular form are organized around a number of nodes, each attached to four to eight subunits. The organization of the mucins in this manner is consistent with efficient packing of a number of large heavily glycosylated monomers while still permitting their rapid unfolding and hydration. For the first time, this provides some insight into how the carbohydrate regions might be organized around the NH2- and COOH-terminal globular protein domains within the granule and also explains how the mucin can expand so rapidly upon its release.
Impaired overload-induced hypertrophy in obese Zucker rat slow-twitch skeletal muscle
Authors: Paturi Satyanarayana , Gutta Anil K. , Kakarla Sunil K. , Katta Anjaiah , Arnold Eric C. , Wu Miaozong , Rice Kevin M. , Blough Eric R.
Published: September 2009

The effect of insulin resistance (IR) on the adaptation of skeletal muscle loading is not well understood. Here we examine whether the soleus muscles of the lean Zucker (LZ) and insulin-resistant obese Zucker (OZ) rat exhibit differences in their ability to undergo muscle hypertrophy following 8 wk of mechanical overload. Four-week-old male LZ ( n = 5) and OZ ( n = 5) rats underwent unilateral surgical ablation of the gastrocnemius muscle while the contralateral hindlimb was used as an internal control. Mechanical overload increased soleus muscle wet weight (LZ 57% and OZ 33%, respectively; P < 0 .05) and average type 1 fiber cross-sectional area (LZ 32% and OZ 5%, respectively; P < 0.05) in LZ and OZ rats, while the magnitude of these increases was greater in the LZ animals ( P < 0 .05). The reduced degree of muscle hypertrophy observed in the OZ animals was associated with decreases in the ability of the OZ soleus muscle to phosphorylate p70s6kThr 389 and mTOR, while phosphorylation of p70s6kThr 389 was increased in the LZ overloaded soleus by 83% ( P < 0 .05). The amount of Tuberin/TSC2 phosphorylation, an inhibitor of mTOR, was unchanged in the LZ soleus after overload while it was increased (68.3%, P < 0.05) in OZ animals. Conversely, AMPK phosphorylation was decreased in the LZ (−22.77%, P < 0 .05) but increased (57%, P < 0 .05) in the OZ soleus with overload. Taken together, these data suggest that IR or other related comorbidities may impair the ability of the soleus to activate mTOR signaling and undergo load-induced muscle hypertrophy.
First-Trimester Uterine Artery Doppler and Serum Pregnancy-Associated Plasma Protein-A in Preeclampsia and Chromosomal Defects
Authors: Staboulidou Ismini , Galindo Alberto , Maiz Nerea , Karagiannis George , Nicolaides Kypros H.
Published: September 2009

Objective: We examined the potential value of the uterine artery pulsatility index (PI) in pregnancies with fetal aneuploidies and in those that developed preeclampsia (PE) with the aim of distinguishing between these complications in pregnancies with low pregnancy-associated plasma protein-A (PAPP-A). Methods: Uterine artery PI and serum PAPP-A at 11–13 weeks were measured in 165 cases of PE, including 33 that required delivery before 34 weeks (early PE) and 132 with late PE, and in 301 cases with aneuploidies, including 200 with trisomy 21. Each case of aneuploidy and PE was matched with 4 unaffected controls. Results: Serum PAPP-A was lower in early PE (0.58 multiples of the normal median, MoM) and in trisomy 21 (0.54 MoM), trisomy 18 (0.22 MoM) and Turner syndrome (0.51 MoM) – but not in late PE (0.90 MoM) – than in controls (1.01 MoM). Uterine artery PI was higher in early PE (1.52 MoM), late PE (1.20 MoM), trisomy 18 (1.20 MoM) and Turner syndrome (1.29 MoM) – but not in trisomy 21 (1.02 MoM) – than in controls (1.0 MoM). Conclusion: The uterine artery PI at 11–13 weeks may be useful in distinguishing between low PAPP-A due to trisomy 21 and early PE.
Diamniotic Omphalopagus Conjoined Twins in a Diamniotic Pregnancy
Authors: Tihtonen K. , Lagerstedt A. , Kähkönen M. , Kirkinen P.
Published: September 2009

Objective: To present antepartal diagnostic findings including 2D/3D ultrasonography in a rare case of conjoined twins with diamniotic placentation. Methods: In ultrasonographic examination, a communicating structure containing solid and cystic components together with cord vessels was found between the fetuses. The long axes of the fetuses were not parallel and they moved independently. Bladder configurations were absent. A fetal membrane from the chorioidal plate was imaged. Results: Postmortem pathological examination revealed that the twins were conjoined by way of fused cloacal exstrophy and omphalocele, and the separate amniotic cavities communicated via a fused allantoic cavity. The placenta was monochorionic and diamniotic. DNA analysis of the twins and the placenta confirmed the monozygotic origin. Conclusion: Visualization of the amniotic membrane does not rule out conjoined twins in rare cases of monochorionic twin pregnancies.
Prenatal Three-Dimensional Images of Proximal Focal Femoral Deficiency Produced by Helical Computed Tomography
Authors: Otera Yuka , Morokuma Seiichi , Yumoto Yasuo , Hojo Satoshi , Gotoh Takako , Hara Toshiro , Ushijima Yasuhiro , Nakashima Yasuharu , Tsukimori Kiyomi , Wake Norio
Published: September 2009

Introduction: Proximal focal femoral deficiency (PFFD) is a rare skeletal disorder characterized by failure in development of the subtrochanteric region of the femoral shaft, with varying degrees of shortening of the proximal femur. Objective: To investigate the potential of helical computed tomography as a prenatal diagnostic tool for bony abnormalities. Case: A 37-year-old Japanese woman was referred to our hospital at 32 weeks of gestation for the evaluation of fetal growth restriction with short femurs. An ultrasound examination revealed the fetus to have short femurs bilaterally with normal echogenicity, and a normal facial profile. Assessment by 3D CT confirmed the absence of the femoral heads bilaterally and also revealed bilateral hip dislocations and oligodactyly of the right hand. The baby was delivered by cesarean section at 37 weeks of gestation, whereupon the diagnosis of PFFD was confirmed. Conclusion: Helical CT is a useful prenatal diagnostic alternative for bony abnormalities that is superior to the conventional sonographic approach.
A Defect in the Antioxidant Defense System in Schizophrenia
Authors: Virit Osman , Altindag Abdurrahman , Yumru Mehmet , Dalkilic Alican , Savas Haluk Asuman , Selek Sahabettin , Erel Ozcan , Herken Hasan
Published: September 2009

Objectives: Several oxidants and antioxidants have been evaluated in schizophrenia. However, previous studies frequently focused on individual parameters. Determination of the total oxidant and antioxidant status may be more useful. Therefore, we aimed to evaluate both plasma total oxidant status (TOS) and total antioxidant status (TAS) together with the oxidative stress index (OSI) in schizophrenia patients for the first time in the literature. Methods: A total of 60 schizophrenia patients and 40 healthy volunteers were included in the study. The Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impression-severity scale (CGI-S) were used to evaluate the severity of schizophrenia in the patients. TOS and TAS were measured in plasma and the OSI was calculated for patients and controls. Results: There was no difference between patients and controls with regard to TOS, but the patients’ TAS and OSI were significantly lower and higher, respectively, than those of the controls. No difference was detected between the schizophrenia subtypes or between the patients on typical or atypical antipsychotic medications or a combination of the two with regard to oxidative parameters. There was a weak to moderately significant negative correlation between TAS and total, positive and general psychopathology PANSS scores. Finally, we found a weak to moderately significant negative correlation between the CGI-S score and TOS and between the CGI-S score and TAS. Conclusions: There is a defect in the antioxidant defense system in schizophrenia. Known oxidative stress that causes oxidative cell damage and thus contributes to the pathophysiology of schizophrenia may be mainly related to this defensive defect.
Study of ACEI versus ARB in Managing Hypertensive Overt Diabetic Nephropathy: Long-Term Analysis
Authors: Ozturk Savas , Sar Fuat , Bengi-Bozkurt Olcay , Kazancioglu Rumeyza
Published: September 2009

Background: There is, to our knowledge, no study that has directly compared angiotensin-converting enzyme inhibitor (ACEI) with angiotensin receptor blocker (ARB) in hypertensive patients with overt diabetic nephropathy (DNP). We tried to analyze the outcomes of hypertensive patients with overt type 2 DNP who used only ACEIs or ARBs. Methods: The patients who had an estimated creatinine clearance <90 ml/min and hypertension or had been using antihypertensive drug(s) at presentation were included in the study. The patients were classified as ACEI group and ARB group. Results: A total of 100 patients (55 men and 45 women, mean age 61.8 ± 9.16 years) were included in the study. Mean duration of follow-up was 24.6 ± 14.1 months. Baseline demographics, biochemical analyses and blood pressures were similar. Renal functions and proteinuria of both groups did not show any significant changes during follow-up. Blood pressure courses were also similar. Although the mean doubling time of creatinine in the ARB group was shorter than the ACEI group, it was not statistically significant. During the follow-up period, 4 patients died (2 in the ACEI group, 2 in the ARB group) and 10 patients were started on dialysis (7 in the ACEI group, 3 in the ARB group). Serum creatinine and the amount of proteinuria were the baseline parameters which were related to the initiation of dialysis. Conclusion: ACEIs and ARBs have similar outcomes in overt DNP. Their renoprotective effects can be observed in spite of uncontrolled hypertension.
Expression of Airway Epithelial Sodium Channel in the Preterm Infant Is Related to Respiratory Distress Syndrome but Unaffected by Repeat Antenatal β-Methasone
Authors: Janér Cecilia , Helve Otto , Pitkänen Olli M. , Kari M. Anneli , Peltoniemi Outi M. , Hallman Mikko , Hovi Petteri , Andersson Sture
Published: September 2009

Background: The airway epithelial sodium channel (ENaC) is rate limiting for postnatal alveolar fluid clearance. Increased lung water content is a feature of respiratory distress syndrome (RDS), which is reduced by antenatal corticosteroid treatment in preterm infants. Objectives: Since corticosteroids also induce ENaC gene expression, we studied whether a repeat dose of antenatal β-methasone affects postnatal expression of airway ENaC. Methods: 17 pregnant women with imminent preterm birth were randomized to receive a single repeat dose of β-methasone (12 mg) or placebo (repeat β-methasone: 8 infants, gestational age (GA) 30.8 ± 2.2 weeks; placebo: 14 infants, GA 30.4 ± 2.7 weeks). Expression of α-, β- and γENaC subunits in nasal epithelium 1–5 and 20–29 h postnatally was analyzed with reverse transcription-PCR. Results: There were no differences between the study groups in RDS incidence or ENaC subunit expression (all p > 0.38). Regression coefficients for association of αENaC expression at 1–5 h with GA in infants with and without RDS differed significantly (p = 0.023). At 20–29 h, αENaC expression was lower in infants with RDS (p = 0.048). Conclusions: A single repeat dose of antenatal β-methasone did not increase ENaC expression, which may in part explain the absence of reduction in RDS incidence.
Systemic and Pulmonary Hemodynamic Responses to Adrenergic and Cholinergic Agonists during Fetal Development
Authors: Nuwayhid B. , Brinkman, III C.R. , Su C. , Bevan J.A. , Assali N.S.
Published: September 2009

Systemic and pulmonary hemodynamic responses to adrenergic and cholinergic agonists were investigated in fetal lambs between 60 days and term gestation. The cardiovascular response to these agents increases with fetal age, and the increase is related to maturation of the effector system rather than the vascular receptors. The fetal pulmonary vascular bed and the ductus arteriosus are the primary components responding to acetylcholine; the systemic response is secondary to that occurring in the lung. Both fetal systemic and pulmonary vascular beds are under α-adrenergic control whereas the fetal heart is under β-adrenergic control.
Effect of Phototherapy on Hepatic Excretory Function in Newborns as Measured by Bromsulphalein Clearance
Authors: Rubaltelli Firmino F. , Donzelli Filiberto , Largajolli Giovanna
Published: September 2009

BSP clearance from the plasma was studied during phototherapy in a group of jaundiced newborns. This therapy did not have any influence on the plasma dye disappearance curve. The obtained results are consistent with the hypothesis that this therapy causes the photodegradation of bilirubin, and that the increased excretion of unconjugated bilirubin is not mediated by a generalized enhancement of the hepatic output.
Effects of Low Humidity on Small Premature Infants in Servocontrol Incubators
Authors: Belgaumkar Teertharaj K. , Scott Kenneth E.
Published: September 2009

Apneic spells were recorded in 8 of 19 premature infants nursed in high and low humidity alternately in servocontrol incubators. A significantly greater proportion of severe apnea occurred in low than in high humidity. It is postulated that this frequency and severity was due to the increased (as well as widely fluctuating) ambient temperature during low humidity.
Adult Isoantigen and Lectin Reactivity of Bovine Fetal Red Cells
Authors: Miller Wilmer J. , Hubbert William T.
Published: September 2009

Evidence is presented that fetal red cell membranes differ from membranes of their dams in isoantigenic and lectin reactivities. Evidence for nonsimultaneous development of ‘adult’ antigenic factors is extended. It is proposed that ‘adult’ phenogroups develop from replacement or displacement of factors in ‘fetal’ phenogroups.
Evidence for Increased Fatty Acid Transfer across the Placenta during a Maternal Fast in Rabbits
Authors: Edson J.L. , Hudson D.G. , Hull D.
Published: September 2009

Fetal rabbits were obtained by Caesarian section from 28-day pregnant does which had been fasted for 48 h (days 26–28). Organ weights, fat contents and blood metabolite levels were compared with a group obtained in a similar manner from non-fasted does. Similar data were obtained for term fetuses (31 days) born by natural delivery. In 28-day pregnant, fasted does, blood levels of free fatty acids (FFA) and glycerol were doubled compared with non-fasted controls. Fetal levels showed a similar increase. Both groups of fetuses from fasted does had increased fat stores both in the liver and adipose tissue. The overall increase in fat stores was 80–100%. It is suggested that during maternal fasting increased amounts of maternal FFA cross the placenta into the fetal circulation and are incorporated into the fetal fat stores.
Metabolic and Hormonal Consequences of Exchange Transfusion via the Umbilical Artery or Vein
Authors: Cser Agnes , Milner R.D.G.
Published: September 2009

Twenty exchange transfusions for hyperbilirubinaemia were performed via the umbilical vein or artery in 17 term and pre-term infants. Blood preserved with acid citrate and dextrose was used and the effect of the route of transfusion on plasma glucose, free fatty acid, insulin and growth hormone (GH) concentrations was measured during the transfusion and for 3 h afterwards. Infants transfused via the umbilical vein secreted more insulin than those transfused via the artery although both groups had similar rises in plasma glucose. After transfusion, glucose disappearance was faster and minimum plasma glucose levels were lower in infants transfused via the vein. This group had a smaller fall in plasma free fatty acids during transfusion, but otherwise plasma free fatty acid levels were similar in both groups. More GH was secreted by infants transfused via the artery resulting in higher plasma levels during and after transfusion.
Growth of Adipose Tissue in the Fetal Rabbit
Authors: Hudson D.G. , Hull D.
Published: September 2009

(1) Fetal rabbits of different gestational ages (20–29 days) were obtained by Caesarian section and term rabbits (31 days) by natural delivery. After dissection, organ weights were obtained and growth curves drawn. Brown adipose tissue was first visible at 22 days gestation and increased relatively more quickly than the body weight till day 26 after which it formed a constant percentage of the body weight. Growth of white adipose tissue followed a similar pattern, except that it was not visible until day 24. (2) The percentage triglyceride content of both types of adipose tissue increased throughout the latter part of gestation. (3) Fetuses of low birth weight had depressed fat stores in brown adipose tissue. Some, but not all, of the high birth weight fetuses had relatively enlarged fat stores. It is suggested that the conditions which produce fetuses of unusually low or high birth weight tend to have a greater corresponding effect on the fetal fat stores.
Disappearance of p-Aminohippurate and Inulin from Plasma of Newborn and Adult Rats
Authors: Pegg D.G. , Hook J.B.
Published: September 2009

The ability of newborn and adult rats to eliminate p-aminohippuric acid and inulin from plasma was determined. The pattern of development is similar to that observed in vitro using renal cortical slices. The fact that function increases to a peak and then declines over the developmental period while organ weight and histology mature progressively suggests a divergence of functional and anatomical maturation. Inulin elimination, unlike PAH, increased over the ages tested, and is apparently more closely related to organ growth.
Assessment of Fetal Rat Parathyroid Gland Activity during Hypocalcemia Induced by EDTA
Authors: Garel Jean-Michel
Published: September 2009

Rat fetuses with or without parathyroid glands (intact or decapitated at 17.5 days of gestation) were injected subcutaneously with the disodium salt of EDTA at 21.5 days of gestation. In the two groups, the unchelated plasma calcium levels were measured within 180 min following the injection. The lowest plasma calcium values were observed 30 min after injection of EDTA in both groups of fetuses. In intact fetuses, the return of plasma calcium levels to normal was completed within 180 min. In decapitated fetuses, recovery was delayed. The marked difference in the recovery curves between the two groups establishes the role of the fetal parathyroid glands in controlling fetal hypocalcemia. Factors which may explain the high plasma calcium level in the rat fetus are discussed in relation to findings from previous reports.
Electrophoretic Mobility of the Fetal Red Blood Cell
Authors: Kosztolányi G. , Jobst K.
Published: September 2009

The electrophoretic mobilities of fetal and adult red blood cells have been examined. The mean mobility values for intact fetal and adult erythrocytes were the same, and there was no difference in mobility between the fetal and adult red blood cells treated with neuraminidase. However, a significant difference was observed after trypsin digestion. This may be due to a difference in composition between the fetal and adult red cell membranes.
Desoxyribonucleic Acid and Pyrimidine Synthesis in the Rat during Intra-Uterine Growth Retardation: Responsiveness of Several Organs
Authors: Roux J.M. , Jahchan T. , Fulchignoni M.C.
Published: September 2009

The response of DNA synthesis, thymidine incorporation and the activities of uridine kinase, carbamyl phosphate synthetase and aspartate transcarbamylase were studied in the rat, following intra-uterine growth retardation. A good correlation was found between the falls of DNA production and thymidine incorporation and the decrease of the activity of the three enzymes during the fetal period. After birth, cell proliferation remained depressed but no further changes occurred in the enzymatic activities.
Effects of Goat Anti-Rat Placenta IgG on the in vitro Uptake of 125 I-Labeled Human Serum Albumin by the Rat Visceral Yolk Sac
Authors: Goetze T. , Franke H. , Oswald B. , Schlag B. , Goetze E.
Published: September 2009

Preincubation of rat visceral yolk sac with goat anti-rat placenta IgG and following incubation with 125I-HSA resulted in a reduction of the uptake of albumin by 30–50 % in comparison with the controls. Inhibitors of respiration or glycolysis impair the ingestion of protein, likewise the reduction of the incubation temperature.
Blood Glucose, Serum Insulin and Glucagon Response to Arginine in Premature Infants
Authors: Falorni A. , Massi-Benedetti F. , Gallo G. , Trabalza N.
Published: September 2009

The effect of arginine infusion on the peripheral blood sugar, plasma insulin and plasma glucagon was studied in 28 appropriate-for-gestational-age premature newborn infants, 1-day-old, and in 12 normal children 4–10 years old. In the premature plasma insulin and glucagon concentrations increased after arginine though less noticeably than in the older children, and their insulin/glucagon molar ratio was low at fasting and did not change after arginine. It is assumed that the endocrine pancreatic activity is already developed at birth and adequate to the metabolic state in neonatal life.
Umbilical Cord Plasma Estradiol Levels in Relation to Complications of Pregnancy and Newborn and to Cortisol Levels
Authors: Sybulski S. , Maughan G.B.
Published: September 2009

The average estradiol concentrations in umbilical cord plasma from newborns which developed respiratory distress with or without hyaline membrane disease (RDS) were lower by 25 % than in controls. Complication of pregnancy by maternal diabetes or pruritus has been associated with abnormalities in estrogen concentrations in the mother, but cord plasma estradiol levels in these cases were essentially normal. Because of reports that treatment of the mother before delivery with estrogens or glucocorticoids results in a decreased incidence of RDS in newborns the relationship between endogenous estradiol and cortisol levels in cord plasma was investigated. There was no significant correlation between the concentrations of these steroids in 65 specimens; the cortisol levels associated with two cases of severe RDS were low.
Phagocytic Cells in Cord Blood
Authors: Prindull Gregor , Prindull Brigitte , Palti Zvi , Yoffey Joseph M.
Published: September 2009

A suspension of fine carbon particles was added to cord blood of healthy premature and full-term infants, and the mixture was incubated for 3 h, after which the uptake of carbon particles by blood leukocytes was examined. The results were compared with those from the blood of adults. A gradient of phagocytic activity was observed. The most active uptake of carbon was by the leukocytes of premature infants, the least active by leukocytes of adults. In cord blood and blood of adults, phagocytic activity was evident in both monocytes and neutrophils..In addition, two types of what have been termed ‘lymphocytoid’ phagocytes were seen. These resemble lymphocytes in their morphology. One type possesses basophilic cytoplasm, and has been found only in premature cord blood. The presence of lymphocytoid phagocytes affords a further indication of the differences between the circulating lymphocyte population in the prenatal and perinatal period as compared with the adult.
Effect of Weanling Malnutrition upon Hepatic Drug Metabolism
Authors: Eriksson Margareta , Catz Charlotte , Yaffe Sumner J.
Published: September 2009

Protein deficiency in post-suckling rats produced changes in the activity of hepatic drug-metabolizing enzymes. Significant decreases occurred in the N-demethylation of aminopyrine, in the azo-reduction of neoprontosil and in sulfokinase activity (using p-nitrophenylsulfate as S04 donor). An increase was recorded for the glucuronidation of p-nitrophenol and no changes were noted in the hydroxylations of hexobarbital and aniline. Refeeding the animals for 3 weeks returned all activities to control values. An exception was the azo-reductase activity indicating either a slower recovery or a permanent change.
Effect of Intrauterine Growth Retardation on the Postnatal Development of D-β-Hydroxybutyrate Dehydrogenase Activity in Rat Brain
Authors: Dahlquist G. , Persson B.
Published: September 2009

The postnatal development of the activity of D-β-hydroxybutyrate dehydrogenase in brain mitochondria was studied in rats with experimentally induced intrauterine growth retardation as compared to normal littermates. Variances in weight of the newborn animals were greater between than within litters, therefore the paired t test was used when analyzing possible differences between intrauterine growth retarded (IUGR) animals and controls. IUGR animals remained smaller as estimated by length and weight than their normal littermates up to the age of 60 days. Brain weight was reduced in newborn and 5-day-old IUGR rats but the brain-body ratio was increased from birth up to 60 days of age. At 20 days of age, when the activity of the enzyme reached a peak value, the growth retarded animals had a significantly lower activity of D-β-hydroxybutyrate dehydrogenase as compared to controls. Plasma glucose concentrations were significantly lower in newborn and 10-day-old IUGR rats as compared to controls. Plasma concentrations of .D-β-hydroxybutyrate and acetoacetate were higher during the suckling period than after weaning, but there were no differences between the growth retarded animals and their normal littermates.