bluuebunny/crossref_metadata_2025_split huggingface dataset:
Warm gas accretion onto the Galaxy
Authors: Bland-Hawthorn J. 
Published: March 2009

AbstractWe present evidence that the accretion of warm gas onto the Galaxy today is at least as important as cold gas accretion. For more than a decade, the source of the bright Hα emission (up to 750 mR†) along the Magellanic Stream has remained a mystery. We present a hydrodynamical model that explains the known properties of the Hα emission and provides new insights on the lifetime of the Stream clouds. The upstream clouds are gradually disrupted due to their interaction with the hot halo gas. The clouds that follow plough into gas ablated from the upstream clouds, leading to shock ionisation at the leading edges of the downstream clouds. Since the following clouds also experience ablation, and weaker Hα (100–200 mR) is quite extensive, a disruptive cascade must be operating along much of the Stream. In order to light up much of the Stream as observed, it must have a small angle of attack (≈ 20°) to the halo, and this may already find support in new Hi observations. Another prediction is that the Balmer ratio (Hα/Hβ) will be substantially enhanced due to the slow shock; this will soon be tested by upcoming WHAM observations in Chile. We find that the clouds are evolving on timescales of 100–200 Myr, such that the Stream must be replenished by the Magellanic Clouds at a fairly constant rate (≳ 0.1 M⊙ yr−1). The ablated material falls onto the Galaxy as a warm drizzle; diffuse ionized gas at 104 K is an important constituent of galactic accretion. The observed Hα emission provides a new constraint on the rate of disruption of the Stream and, consequently, the infall rate of metal-poor gas onto the Galaxy. We consider the stability of Hi clouds falling towards the Galactic disk and show that most of these must break down into smaller fragments that become partially ionized. The Galactic halo is expected to have huge numbers of smaller neutral and ionized fragments. When the ionized component of the infalling gas is accounted for, the rate of gas accretion is ~0.4 M⊙ yr−1, roughly twice the rate deduced from Hi observations alone.
Group infall of substructures on to a Milky Way-like dark halo
Authors: Li Yang-Shyang , Helmi Amina 
Published: March 2009

AbstractWe report the discovery that substructures/subhaloes of a galaxy-size halo tend to fall in together in groups in cosmological simulations, something that may explain the oddity of the MW satellite distribution. The original clustering at the time of infall is still discernible in the angular momenta of the subhaloes even for events which took place up to eight Gyrs ago, z ~ 1. This phenomenon appears to be rather common since at least 1/3 of the present-day subhaloes have fallen in groups in our simulations. Hence, this may well explain the Lynden-Bell & Lynden-Bell ghostly streams. We have also found that the probability of building up a flattened distribution similar to the MW satellites is as high as ~ 80% if the MW satellites were from only one group and ~ 20% when five groups are involved. Therefore, we conclude that the ‘peculiar’ distribution of satellites around the MW can be expected with the CDM structure formation theory. This non-random assignment of satellites to subhaloes implies an environmental dependence on whether these low-mass objects are able to form stars, possibly related to the nature of reionization in the early Universe.
The Challenge of Modelling Galactic Disks
Authors: Burkert Andreas 
Published: March 2009

AbstractDetailed models of galactic disk formation and evolution require knowledge about the initial conditions under which disk galaxies form, the boundary conditions that affect their secular evolution and the microphysical processes that drive the multi-phase interstellar medium and regulate star formation. Unfortunately, up to now, most of these ingredients are still poorly understood. The challenge therefore is to still construct realistic models of galactic disks with predictive power.
Physiology and behaviour of marine Thioploca
Authors: Høgslund Signe , Revsbech Niels Peter , Kuenen J Gijs , Jørgensen Bo Barker , Gallardo Victor Ariel , Vossenberg Jack , Nielsen Jeppe Lund , Holmkvist Lars , Arning Esther T , Nielsen Lars Peter 
Published: March 2009

Abstract
Among prokaryotes, the large vacuolated marine sulphur bacteria are unique in their ability to store, transport and metabolize significant quantities of sulphur, nitrogen, phosphorus and carbon compounds. In this study, unresolved questions of metabolism, storage management and behaviour were addressed in laboratory experiments with Thioploca species collected on the continental shelf off Chile. The Thioploca cells had an aerobic metabolism with a potential oxygen uptake rate of 1760 μmol O2 per dm3 biovolume per h, equivalent to 4.4 nmol O2 per min per mg protein. When high ambient sulphide concentrations (∼200 μm) were present, a sulphide uptake of 6220±2230 μmol H2S per dm3 per h, (mean±s.e.m., n=4) was measured. This sulphide uptake rate was six times higher than the oxidation rate of elemental sulphur by oxygen or nitrate, thus indicating a rapid sulphur accumulation by Thioploca. Thioploca reduce nitrate to ammonium and we found that dinitrogen was not produced, neither through denitrification nor through anammox activity. Unexpectedly, polyphosphate storage was not detectable by microautoradiography in physiological assays or by staining and microscopy. Carbon dioxide fixation increased when nitrate and nitrite were externally available and when organic carbon was added to incubations. Sulphide addition did not increase carbon dioxide fixation, indicating that Thioploca use excess of sulphide to rapidly accumulate sulphur rather than to accelerate growth. This is interpreted as an adaptation to infrequent high sulphate reduction rates in the seabed. The physiology and behaviour of Thioploca are summarized and the adaptations to an environment, dominated by infrequent oxygen availability and periods of high sulphide abundance, are discussed.
The importance of maternal BMI on infant's birth weight in four BMI groups for the period 1978–2001
Authors: BRYNHILDSEN JAN , SYDSJÖ ADAM , EKHOLM‐SELLING KATARINA , JOSEFSSON ANN 
Published: March 2009

AbstractObjective. To study whether increased maternal weight and other factors of importance is associated with higher birth weights of the children over a period of almost 25 years. Design. Retrospective cohort study. Setting. Delivery wards in southeast Sweden. Sample. A total of 4,330 delivered women and their children from the years 1978, 1986, 1992, 1997, and 2001. Methods. Analysis of covariance was used to evaluate the importance of the mother's body mass index (BMI) on the children's birth weights during the study years and smoking, parity, employment, gestational age, and the age of the mothers were adjusted for. Main outcome measures. Weight of the offspring in relation to maternal BMI and possible confounders such as smoking, parity, employment, gestational age, and the age of the mother. Results. Between 1978 and 1992, there was an increase in birth weight in each of the four BMI categories (i.e. BMI<20, 20–24.9, 25–29.9 and ≥30, respectively) even after adjustments were made for relevant background characteristics (p<0.001). However, between 1992 and 2001, the birth weight for children whose mothers had a BMI of less than 20 or between 20 and 24.9 decreased (p<0.001). For almost every study year, the mothers’ BMI was of significant influence on the children's birth weights. However, the proportion of variance explained by the models (i.e. the adjusted R2) was not substantially altered when the mother's BMI was excluded from the models. Conclusion. Maternal BMI is of significance to explain trends in infants’ birth weight over time, but not of sole importance.
Bayesian survey-based assessment of North Sea plaice (Pleuronectes platessa): extracting integrated signals from multiple surveys
Authors: Bogaards Johannes A. , Kraak Sarah B. M. , Rijnsdorp Adriaan D. 
Published: March 2009

Abstract
Bogaards, J. A., Kraak, S. B. M., and Rijnsdorp, A. D. 2009. Bayesian survey-based assessment of North Sea plaice (Pleuronectes platessa): extracting integrated signals from multiple surveys. – ICES Journal of Marine Science, 66: 665–679. Dependence on a relatively small sample size is generally viewed as a big disadvantage for survey-based assessments. We propose an integrated catch-at-age model for research vessel data derived from multiple surveys, and illustrate its utility in estimating trends in North Sea plaice abundance and fishing mortality. Parameter estimates were obtained by Bayesian analysis, which allows for estimation of uncertainty in model parameters attributable to measurement error. Model results indicated constant fishing selectivity over the distribution area of the North Sea plaice stock, with decreased selectivity at older age. Whereas separate analyses of survey datasets suggested different biomass trends in the southeast than in the western and central North Sea, a combined analysis demonstrated that the observations in both subareas were compatible and that spawning-stock biomass has been increasing over the period 1996–2005. The annual proportion of fish that dispersed in a northwesterly direction was estimated to increase from about 10% at age 2 to 33% at age 5 and older. We also found higher fishing mortality rates than reported in ICES assessments, which could be the consequence of inadequate specification of catchability-at-age in this study or underestimated fishing mortality by the conventional ICES assessment, which relies on official landings figures.
Dynamic Interaction of Craniofacial Structures during Head Positioning and Direct Laryngoscopy in Anesthetized Patients with and without Difficult Laryngoscopy
Authors: Kitamura Yuji , Isono Shiroh , Suzuki Noriko , Sato Yumi , Nishino Takashi 
Published: March 2009

Background
We lack fundamental knowledge of the mechanisms of difficult laryngoscopy despite its clinical significance. The aim of this study was to examine how head positioning and direct laryngoscopy alter arrangements of craniofacial structures.

Methods
Digital photographs of the lateral view of the head and neck were taken at each step of head positioning and direct laryngoscopy in age- and body mass index-matched patients with (n = 13) and without (n = 13) difficult laryngoscopy during general anesthesia with muscle paralysis. The images were used for measurements of various craniofacial dimensions.

Results
Both simple neck extension and the sniffing position produced a caudal shift of the mandible and a downward shift of the larynx, resulting in an increase of the submandibular space. Direct laryngoscopy during the sniffing position displaced the mandible and tongue base upward and caudally, and the larynx downward and caudally, increasing the submandibular space and facilitating vertical arrangement of the mandible, tongue base, and larynx to the facial line. These structural arrangements in response to direct laryngoscopy were not observed in patients with difficult laryngoscopy, whereas head positioning produced similar structural arrangements in patients with and without difficult laryngoscopy.

Conclusion
Increase in the submandibular space and a vertical arrangement of the mandible, tongue base, and larynx to the facial line seem to be important mechanisms for improving the laryngeal view during head positioning and direct laryngoscopy. Failure of these structural arrangements in response to direct laryngoscopy may result in difficult laryngoscopy.
Monitoring of the Sublingual Microcirculation in Cardiac Surgery Using Orthogonal Polarization Spectral Imaging
Authors: Bauer Andreas , Kofler Sieglinde , Thiel Manfred , Eifert Sandra , Christ Frank 
Published: March 2009

Background
The recent introduction of orthogonal polarization spectral imaging enables the direct visualization of the microcirculation of man without imaging enhancing dyes. The authors studied the changes in microvascular perfusion of sublingual mucosa during cardiac surgery with the use of cardiopulmonary bypass (CPB) using this optical method.

Method
Orthogonal polarization spectral images were recorded in 47 patients after skin incision (T1), after the start of CPB (T2), in the late phase of CPB (T3), and 1 h after the discontinuation of CPB (T4). The images were analyzed for microvascular diameter, erythrocyte velocity, and functional capillary density using an established analysis routine for intravital microscopy studies. In a subpopulation (n = 8), the expression of the adhesion molecules CD18 on circulation leukocytes was compared with the number of visualized rolling leukocytes.

Results
Preoperatively, no significant changes of the microvascular diameter and erythrocyte velocity were seen. The functional capillary density was significantly reduced at T3 to 90% of the values observed before CPB but recovered at T4 and showed a weak but significant correlation with body temperature (r = 0.38, P < 0.01) and hemoglobin concentration (r = 0.20, P < 0.05). Expression of CD18 was significantly increased in the late phase of CPB (T3) only, whereas the numbers of rolling leukocytes increased during CPB and revealed a significant threefold increase 1 h after termination of CPB.

Conclusions
Orthogonal polarization spectral imaging revealed no major changes of microvascular perfusion during uncomplicated hypothermic CPB. The slightly reduced functional capillary density during CPB may be caused by several factors all present during CPB, including hypothermia, the artificial extracorporeal perfusion, surgical trauma, hemodilution, and inflammatory reaction. The current data do not allow differentiation between the effects of those possible causes.
Nitrosative Stress and Myocardial Sarcoplasmic Endoreticular Calcium Adenosine Triphosphatase Subtype 2a Activity after Lung Resection in Swine
Authors: Heerdt Paul M. , Lane Paul , Pan Brian Y. , Schaefer Ulrich , Crabtree Mark , Hong Roger , Singer Andrew A. M. , Levi Roberto , Park Bernard J. 
Published: March 2009

Background
Chronic, disease-associated oxidative stress induces myocardial peroxynitrite formation that may lead to nitrosative inhibition of the calcium cycling protein sarcoplasmic endoreticular calcium adenosine triphosphatase subtype 2a (SERCA2a). The current study was designed to test the hypothesis that the acute oxidative stress associated with lung resection also induces myocardial nitrosative stress and alters SERCA2a activity.

Methods
Ventricular myocardium from 16 swine was studied; 11 animals had undergone left upper lobectomy (n = 7) or sham thoracotomy (n = 4) 3 days before harvest, and 5 were nonoperated controls. Tissue peroxynitrite was assessed by measurement of 3-nitrotyrosine incorporation into proteins. SERCA2a activity was determined from indo-1 uptake by isolated sarcoplasmic reticular membranes. Expression of SERCA2a and its regulatory protein phospholamban were determined by Western blotting, as was the phospholamban phosphorylation state (when dephosporylated, phospholamban inhibits SERCA2a). Mechanical significance of changes in SERCA2a activity was assessed from the force-frequency relation of isometric myocardial trabeculae.

Results
Relative to both the control and sham groups, lobectomy animals exhibited a greater than twofold higher myocardial 3-nitrotyrosine incorporation and an approximately 50% lower SERCA2a activity, but no difference in SERCA2a or phospholamban expression or phospholamban phosphorylation. Concomitantly, whereas the trabecular force-frequency relation of control animals was positive, that of lobectomy animals was negative, consistent with impaired calcium cycling.

Conclusions
These data indicate that oxidative/nitrosative stress associated with lung resection influences SERCA2a activity independent of any influence on protein expression or phospholamban phosphorylation. The findings link an acute event with a subcellular process primarily described for chronic illness and suggest a biochemical basis for perioperative changes in myocardial mechanical reserve.
An Evolutionarily Conserved Presynaptic Protein Is Required for Isoflurane Sensitivity in Caenorhabditis elegans
Authors: Metz Laura B. , Dasgupta Nupur , Liu Christine , Hunt Stephen J. , Crowder C Michael 
Published: March 2009

Background
Volatile general anesthetics inhibit neurotransmitter release by an unknown mechanism. A mutation in the presynaptic soluble NSF attachment protein receptor (SNARE) protein syntaxin 1A was previously shown to antagonize the anesthetic isoflurane in Caenorhabditis elegans. The mechanism underlying this antagonism may identify presynaptic anesthetic targets relevant to human anesthesia.

Methods
Sensitivity to isoflurane concentrations in the human clinical range was measured in locomotion assays on adult C. elegans. Sensitivity to the acetylcholinesterase inhibitor aldicarb was used as an assay for the global level of C. elegans neurotransmitter release. Comparisons of isoflurane sensitivity (measured by the EC50) were made by simultaneous curve fitting and F test as described by Waud.

Results
Expression of a truncated syntaxin fragment (residues 1-106) antagonized isoflurane sensitivity in C. elegans. This portion of syntaxin interacts with the presynaptic protein UNC-13, suggesting the hypothesis that truncated syntaxin binds to UNC-13 and antagonizes an inhibitory effect of isoflurane on UNC-13 function. Consistent with this hypothesis, overexpression of UNC-13 suppressed the isoflurane resistance of the truncated syntaxins, and unc-13 loss-of-function mutants were highly isoflurane resistant. Normal anesthetic sensitivity was restored by full-length UNC-13, by a shortened form of UNC-13 lacking a C2 domain, but not by a membrane-targeted UNC-13 that might bypass isoflurane inhibition of membrane translocation of UNC-13. Isoflurane was found to inhibit synaptic localization of UNC-13.

Conclusions
These data show that UNC-13, an evolutionarily conserved protein that promotes neurotransmitter release, is necessary for isoflurane sensitivity in C. elegans and suggest that its vertebrate homologs may be a component of the general anesthetic mechanism.
Photo-activated Azi-Etomidate, a General Anesthetic Photolabel, Irreversibly Enhances Gating and Desensitization of γ-Aminobutyric Acid Type A Receptors
Authors: Zhong Huijun , Rüsch Dirk , Forman Stuart A. 
Published: March 2009

Background
The general anesthetic etomidate acts via gamma-aminobutyric acid type A (GABA(A)) receptors, enhancing activation at low GABA and prolonging deactivation. Azi-etomidate is a photo-reactive etomidate derivative with similar pharmacological actions, which has been used to identify putative binding sites. The authors examine the irreversible effects of azi-etomidate photo-modification on functional GABA(A) receptors in cell membranes.

Methods
GABA(A) receptors (alpha1beta2gamma2L) were expressed in both Xenopus oocytes and human embryonic kidney cells exposed to 365 nm light-activated azi-etomidate with or without GABA, then extensively washed. Receptor-mediated chloride currents were measured using voltage clamp electrophysiology to assess the ratio of peak responses at 10 microm and 1 mm GABA (I10/I1000) and deactivation time course.

Results
After azi-etomidate photo-modification, I10/I1000 ratios were persistently enhanced and deactivation was prolonged, mimicking reversible azi-etomidate actions. Azi-etomidate and ultraviolet light were required to produce irreversible receptor modulation. Adding GABA during photo-modification greatly enhanced irreversible modulation. Azi-etomidate modification also dose-dependently reduced maximal GABA-activated currents, consistent with accumulation of permanently desensitized receptors. Excess etomidate during azi-etomidate photo-modification competitively reduced permanent desensitization. Persistent channel modulation was blocked by 320-fold excess etomidate but enhanced when 32-fold excess etomidate was present.

Conclusions
Azi-etomidate efficiently photo-modifies etomidate sites on GABA(A) receptors in intact cells, producing persistent functional changes that mimic its reversible effects. The results demonstrate sequential modification at more than one etomidate site per receptor. The sites display reciprocal positive cooperativity. In combination with focal photo-activation, azi-etomidate may prove useful for studies of anesthetic actions in neural circuits.
The Effects of Mild Perioperative Hypothermia on Blood Loss and Transfusion Requirement
Authors: Rajagopalan Suman , Mascha Edward , Na Jie , Sessler Daniel I. 
Published: March 2009

Background
Anesthetic-induced hypothermia is known to reduce platelet function and impair enzymes of the coagulation cascade. The objective of this meta-analysis and systematic review was to evaluate the hypothesis that mild perioperative hypothermia increases surgical blood loss and transfusion requirement.

Methods
The authors conducted a systematic search of published randomized trials that compared blood loss and/or transfusion requirements in normothermic and mildly hypothermic (34-36 degrees C) surgical patients. Results are expressed as a ratio of the means or relative risks and 95% confidence intervals (CI); P < 0.05 was considered statistically significant.

Results
Fourteen studies were included in analysis of blood loss, and 10 in the transfusion analysis. The median (quartiles) temperature difference between the normothermic and hypothermic patients among studies was 0.85 degrees C (0.60 degrees C versus 1.1 degrees C). The ratio of geometric means of total blood loss in the normothermic and hypothermic patients was 0.84 (0.74 versus 0.96), P = 0.009. Normothermia also reduced transfusion requirement, with an overall estimated relative risk of 0.78 (95% CI 0.63, 0.97), P = 0.027.

Conclusion
Even mild hypothermia (<1 degree C) significantly increases blood loss by approximately 16% (4-26%) and increases the relative risk for transfusion by approximately 22% (3-37%). Maintaining perioperative normothermia reduces blood loss and transfusion requirement by clinically important amounts.
Measuring the Body Composition of Preterm and Term Neonates: From Research to Clinical Applications
Authors: Roggero Paola , Giannì Maria Lorella , Amato Orsola , Agosti Massimo , Fumagalli Monica , Mosca Fabio 
Published: March 2009

ABSTRACTAssessment of body and weight gain composition is one of the major keys for the evaluation of nutritional requirements in preterm and term infants. The changes in body composition during the first years of life seem to play an important role in the nutritional programming of adult morbidity. Noninvasive and indirect techniques are the most suitable methods for measuring body composition in preterm and term infants. Most of these techniques are used in clinical practice, whereas others are used mainly for research.