bluuebunny/crossref_metadata_2025 huggingface dataset:
Approximate Bayesian computation for modular inference problems with many parameters: the example of migration rates
Authors: Aeschbacher S. , Futschik A. , Beaumont M. A.
Published: January 2013

We propose a two‐step procedure for estimating multiple migration rates in an approximate Bayesian computation (ABC) framework, accounting for global nuisance parameters. The approach is not limited to migration, but generally of interest for inference problems with multiple parameters and a modular structure (e.g. independent sets of demes or loci). We condition on a known, but complex demographic model of a spatially subdivided population, motivated by the reintroduction of Alpine ibex (Capra ibex) into Switzerland. In the first step, the global parameters ancestral mutation rate and male mating skew have been estimated for the whole population in Aeschbacher et al. (Genetics 2012; 192: 1027). In the second step, we estimate in this study the migration rates independently for clusters of demes putatively connected by migration. For large clusters (many migration rates), ABC faces the problem of too many summary statistics. We therefore assess by simulation if estimation per pair of demes is a valid alternative. We find that the trade‐off between reduced dimensionality for the pairwise estimation on the one hand and lower accuracy due to the assumption of pairwise independence on the other depends on the number of migration rates to be inferred: the accuracy of the pairwise approach increases with the number of parameters, relative to the joint estimation approach. To distinguish between low and zero migration, we perform ABC‐type model comparison between a model with migration and one without. Applying the approach to microsatellite data from Alpine ibex, we find no evidence for substantial gene flow via migration, except for one pair of demes in one direction.
Physical restraints practice in adult intensive care units in Egypt
Authors: Kandeel Nahed Attia , Attia Amal Kadry
Published: January 2013

Physical restraints are commonly used in intensive care units to reduce the risk of injury and ensure patient safety. However, there is still controversy regarding the practice of physical restraints in such units. The purpose of this study was to investigate the practices of physical restraints among critical care nurses in El‐Mansoura City, Egypt. The study involved a convenience sample of 275 critically ill adult patients, and 153 nurses. Data were collected from 11 intensive care units using a “physical restraint observation form” and a “structured questionnaire.” The results revealed that physical restraint was commonly used to ensure patient safety. Assessment of physical restraint was mainly restricted to peripheral circulation. The most commonly reported physically restrained site complications included: redness, bruising, swelling, and edema. The results illustrated a lack of documentation on physical restraint and a lack of education of patients and their families about the rationale of physical restraint usage. The study shed light on the need for standard guidelines and policies for physical restraint practices in Egyptian intensive care units.
Predischarge education improves adherence to a healthy lifestyle among Jordanian patients with acute coronary syndrome
Authors: Eshah Nidal F.
Published: January 2013

Risk factor reduction and modification of patient lifestyle have become the focus of secondary prevention and cardiac rehabilitation programs. Considering the scarcity of resources in developing countries, nurses can potentially provide great benefit to acute coronary syndrome patients by utilizing hospital time to teach the patients how to lower their risk for recurrence and adopt healthier lifestyles after discharge. The purpose of this study was to identify the effectiveness of a predischarge education on acute coronary syndrome patients' lifestyles. Quasi‐experimental pretest–post‐test design was used. The patients assigned to the experimental group were offered predischarge education that stimulates lifestyle modification and adoption of a healthier lifestyle. The experimental group scored significantly higher than the control group in three lifestyle components – health responsibilities, nutrition, and interpersonal relations. In conclusion, predischarge education helps motivate acute coronary syndrome patients to adhere to a healthy lifestyle postdischarge. Therefore, nurses must be educated and prepared to be qualified health educators, and health education should continue as one of the most important daily nursing practices, thus it is invested in the preparation of acute coronary patients' discharge plan.
Use of Intracardiac Echocardiography during Atrial Fibrillation Ablation
Authors: RUISI CHRISTOPHER P. , BRYSIEWICZ NEIL , ASNES JEREMY D. , SUGENG LISSA , MARIEB MARK , CLANCY JUDE , AKAR JOSEPH G.
Published: January 2013

As the volume and complexity of catheter ablation of atrial fibrillation (AF) continue to rise, there is increasing attention directed at reducing exposure to ionizing radiation. This has led to the emergence of intracardiac echocardiography (ICE) as a stand‐alone imaging modality guiding AF ablation. In addition to directing transseptal puncture, ICE may be used to identify left atrial structures and to guide the manipulation of catheters. ICE may also be used to visualize the esophagus in real‐time and to assist with early identification of procedural complications. This review provides detailed step‐by‐step directions for identification of relevant structures and summarizes the use of ICE during AF ablation.
Resetting and Entrainment of Reentrant Arrhythmias: Part I: Concepts, Recognition, and Protocol for Evaluation: Surface ECG versus Intracardiac Recordings
Authors: ALMENDRAL JESÚS , CAULIER‐CISTERNA RAÚL , ROJO‐ÁLVAREZ JOSÉ LUIS
Published: January 2013

In this paper, we review the information accumulated over the years regarding the phenomena of resetting and entrainment of reentrant arrhythmias. Over three decades of research and clinical applications, these phenomena have demonstrated that they stay as a main tool for an intellectual understanding of reentry and to base strategies for localization of critical areas for ablative therapies. This review will be divided into two parts. This first part deals with the bases for the concept development, the means for the detection of these phenomena, and their mechanistic implications. Resetting is described as a particular response of a given rhythm to an external perturbation, indicating interaction between them. Entrainment indicates continuous reset of the rhythm when the perturbation is repetitive. The mechanisms that explain these responses in reentrant rhythms are presented. Fusion, both at the surface electrocardiogram and at the level of intracardiac recordings, is discussed in detail, with its value and limitations as a key concept to recognize entrainment and reentry. Computer simulations are used as an aid to a better understanding. Differences between resetting and entrainment are considered, and a pacing protocol to study these phenomena described.
Programmed versus Effective VV Delay during CRT Optimization: When What You See Is Not What You Get
Authors: BOGAARD MARGOT D. , MEINE MATHIAS , DOEVENDANS PIETER A.
Published: January 2013

Background

In cardiac resynchronization therapy (CRT) devices, the interventricular (VV) delay denotes the time interval between left (LV) and right ventricular (RV) pacing. This study aimed to determine the proportion of patients in whom the effective VV delay (VVeff, delay between LV and RV depolarization, being induced either by pacing or intrinsic conduction) is different from the programmed VV delay during a standard VV delay optimization procedure.

Methods

Thirty‐three patients with heart failure and left bundle branch block configuration without total atrioventricular (AV) block receiving CRT were prospectively included. VVeff was calculated from intrinsic AV intervals, programmed optimal AV delay, and programming system. Intrinsic AV intervals were measured on intracardiac electrograms. The optimal AV and VV delays were determined by highest increase in maximum rate of LV pressure rise (dP/dtmax). VV delays of 20–80 ms LV and RV preactivation were tested.

Results

Calculated maximum possible VVeff was shorter than 80 ms LV preactivation in up to 46% of patients and shorter than 40 ms LV preactivation in up to 3% of the patients. These proportions were 6% and 0% during 80 and 40 ms RV preactivation, respectively.

Conclusions

In CRT patients with left bundle branch block without total AV block, the effective VV delay is shorter than the programmed VV delay during a standard optimization procedure in approximately half of the patients and this phenomenon is encountered predominantly during LV preactivation by 40 ms or more. Calculation of the individual maximum VVeff in advance can shorten the VV delay optimization procedure.
Larger Interventricular Conduction Time Enhances Mechanical Response to Resynchronization Therapy
Authors: PADELETTI LUIGI , PIERAGNOLI PAOLO , RICCIARDI GIUSEPPE , PERROTTA LAURA , PERINI ALESSANDRO P. , GRIFONI GINO , RICCERI ILARIA , PADELETTI MARGHERITA , LIONETTI VINCENZO , VALSECCHI SERGIO
Published: January 2013

Background

Previous studies have reported that the left ventricular (LV) pacing site is a major determinant of the hemodynamic response to cardiac resynchronization therapy (CRT). However, lead positioning in a lateral or posterolateral cardiac vein may not be optimal for every patient. The objective of this study was to assess the relationship between the right ventricular (RV)‐to‐LV conduction time and the systolic function during CRT on the basis of changes to LV pressure‐volume loops.

Methods

Left ventricular pressure and volume data were determined using a conductance catheter during CRT device implantation in 10 patients. Four endocardial LV sites were systematically assessed at four atrioventricular delays. The RV‐to‐LV conduction time was measured as the time interval between spontaneous peak R waves, recorded through the RV lead and the LV catheter.

Results

The optimal pacing site varied among patients. However, the pacing site associated with the maximum RV‐to‐LV conduction time resulted in a stroke volume improvement comparable to the pacing site identified through individual hemodynamic optimization (41 ± 17 mL vs 44 ± 18 mL, P = 0.266). Moreover, the RV‐to‐LV conduction time recorded at each endocardial pacing site correlated positively with the increase in stroke volume (r = 0.537; P < 0.001), stroke work (r = 0.642; P < 0.001), and the pressure‐derivative maximum (r = 0.646; P < 0.001) obtained with CRT.

Conclusions

An optimal acute response to CRT can be obtained by positioning the LV lead at the site associated with the maximum RV‐to‐LV conduction time. A significant correlation appears to exist between RV‐to‐LV conduction time and the improvement in systolic function with CRT.
Are Plasma Natriuretic Peptide Levels Influenced by Automatic Pacemaker Algorithms for Ventricular Pacing Minimization?
Authors: KREUZER JOERG , LENNERZ CARSTEN , DIETL JOSEF U. , BEIER THOMAS , STRAUCH ALEXEJ , SEMMLER VERENA , BADRAN HAITHAM , ZRENNER BERNHARD , KOLB CHRISTOF
Published: January 2013

Background

Automatic atrioventricular search hysteresis (AVSH) is designed to reduce the cumulative percentage of potentially deleterious right ventricular apical pacing (VP%) in dual‐chamber pacemakers. We investigated whether minimizing VP% by AVSH can, in turn, reduce ventricular wall stretching/stress, as assessed by plasma concentrations of the amino‐terminal fragment of the pro‐B‐type natriuretic peptide (NT‐proBNP).

Methods

After dual‐chamber pacemaker implantation in 81 patients (age: 69 ± 11 years; males: 55.6%), the fixed atrioventricular delay of 225 ms was programmed and AVSH was turned off for 1 month. The patients were thereafter randomly assigned to standard AVSH for 1 month, followed by an enhanced AVSH for another month, or vice versa. At the 1‐, 2‐, and 3‐month follow‐ups, VP% values were retrieved from the pacemaker memory, and venous blood samples were taken for NT‐proBNP measurements.

Results

Both standard and enhanced AVSH reduced the median VP% value from 38.5% (for the fixed atrioventricular delay) to 2.1% (P < 0.001). However, plasma NT‐proBNP concentrations for the fixed atrioventricular delay (median, 253 pg/mL), standard AVSH (225 pg/mL), and enhanced AVSH (276 pg/mL) did not differ significantly on the intrapatient basis (paired Wilcoxon tests) between any pair of these modalities.

Conclusion

Minimizing ventricular pacing by AVSH during 1 month had no influence on plasma NT‐proBNP levels (i.e., ventricular wall stretching/stress) compared with a constant, moderately prolonged atrioventricular delay.
Laser Lead Extraction in Congenital Heart Disease: A Case‐Controlled Study
Authors: McCANTA ANTHONY C. , KONG MELISSA H. , CARBONI MICHAEL P. , GREENFIELD RUTH A. , HRANITZKY PATRICK M. , KANTER RONALD J.
Published: January 2013

Introduction

Patients with congenital heart disease (CHD) and implanted cardiac rhythm management devices have a high rate of endocardial lead issues requiring lead extraction. Laser lead extraction (LLE) is a promising modality for lead management though few studies have evaluated this technique in CHD.

Methods

This is a retrospective, case‐controlled (gender‐ and age‐matched, without CHD) analysis of all CHD patients from 2002–2010 at a single institution who underwent LLE as a primary extraction modality. The aim is to evaluate the utility of LLE in patients with CHD compared with controls without CHD. The primary outcome is LLE clinical success. Secondary outcomes include procedural success, complications, and factors related to LLE failure.

Results

Twenty‐two patients with CHD underwent 24 LLE procedures to extract 35 leads. These were compared with 22 patients without CHD who underwent 24 LLE procedures to extract 37 leads. LLE clinical success was achieved for 26 of 35 leads (74%) in patients with CHD versus 35 of 37 leads (92%) in patients without CHD [P = 0.02]. No factors within the CHD group predicted LLE failure. Six of the nine leads for which LLE was unsuccessful were extracted using other methods. No complications were observed in the CHD group.

Conclusions

Patients with CHD are less likely to have successful LLE than gender‐ and age‐matched controls without CHD. LLE failures in CHD may be related to calcified adhesions. Mechanical‐rotational devices and the femoral snare technique are useful for LLE failures. LLE provides an effective first‐line approach for patients with CHD.
Early Repolarization Variant in Syncopal Patients Referred to Tilt Testing
Authors: BARTCZAK ANNA , LELONEK MALGORZATA
Published: January 2013

Background

Early repolarization variant (ERV) was recently described as an electrocardiogram (ECG) pattern associated with increased risk of sudden cardiac death (SCD) in some populations. We decided to establish the significance of ERV in syncopal patients referred to tilt testing due to suspected reflex syncope.

Methods

From 160 consecutive patients (mean age 36.6 ± 15 years) history of syncopal episodes and resting ECG were collected. ERV was diagnosed if elevation of point J ≥0.1 mV was in ≥2 ECG leads II, III, aVF and/or I, aVL, V4–V6. Analysis was performed in regard to ERV and degree of J‐point elevation (JPE; ≥2 mV vs <2 mV). Patients were at 2 years follow‐up.

Results

ERV was present in 31% of patients. The most frequent was the ascending ST elevation variant (84%) and lateral ECG locations (74%). The degree of JPE did not differentiate the studied patients. Male sex was associated with the higher risk of ERV (odds ratio [OR] = 2.84; P = 0.003). ERV in inferior ECG leads enhanced the risk of positive tilt testing (OR = 3.57; P = 0.048). There was no relationship between ERV and injuries or syncopal history. No deaths were observed in follow‐up.

Conclusions

Among middle‐aged people referred to tilt testing due to suspected reflex syncope the ascending ST elevation type was the most frequent variant of ERV and in midterm follow‐up there were no deaths. In this population ERV was frequent and associated with positive tilt testing. According to recently described higher risk of SCD among people with ERV, we need further studies and longer follow‐up to establish the clinical importance of ERV in patients with reflex syncope.
Threshold Currents of Platinum Electrodes used for Functional Electrical Stimulation of the Phrenic Nerves for Treatment of Central Apnea
Authors: HIRSCHFELD SVEN , VIEWEG HENDRYK , SCHULZ ARNDT P. , THIETJE ROLAND , BAER GERHARD A.
Published: January 2013

Background

Stability of threshold currents during long‐term use of phrenic nerve stimulation has been questioned.

Methods and Results

Between January 5, 1988, and March 5, 2008, 49 patients with functional C2‐tetraplegia received an Atrostim PNS (Atrotech Ltd., Tampere, Finland) as treatment of their respiratory insufficiency; a follow‐up of 35 of such patients was carried out exclusively in our institution for 6.3 (4.44) 0.04–15.75 years (mean [standard deviation (SD)] range). The device employed four‐pole sequential nerve stimulation, which provided four threshold currents subsequently evaluated for each phrenic nerve. Stimulation data were prospectively recorded. The differences between threshold currents recorded 1 year after implantation and the last recorded values were 0.33–0.43 (0.44–0.63) 0–2.9 mA. After having excluded the data of eight patients with values >1 mA (= mean + SD), we registered the differences for the remaining patients of 0.15–0.24 (0.14–0.24) 0–0.95 mA, which is just twice the adjustment accuracy of the device. Out of the eight problem cases one had, and two were suspected to have, surgical trauma; all three nerves recovered. In two cases the values steadily increasing over years might have been caused by unspecific foreign body reaction. Two cases with values >1mA for different durations at different electrodes might be caused by biofilm, and one patient displaying steadily increasing values lived, unwilling to live, only 2 years after the implantation.

Conclusion

Thus, there was no permanent nerve injury and in 77% of the presented cases threshold currents remained stable.
Propofol infusion syndrome or adrenoleukodystrophy?
Authors: Karaman Yucel , Goktay Aylin , Agin Hasan , Karaarslan Utku
Published: January 2013

Following a propofol anesthetic, a 5‐year‐old girl with lower extremity spasticity seized and developed hypertriglyceridemia, hyperkalemia, and metabolic acidosis. A presumed diagnosis of propofol infusion syndrome (PRIS) was made, but further investigation revealed neonatal adrenoleukodystrophy. PRIS should be considered with this constellation of symptoms, but other neurometabolic disorders must always be ruled out.
Earlier detection of coagulopathy with thromboelastometry during pediatric cardiac surgery: a prospective observational study
Authors: Romlin Birgitta S. , Wåhlander Håkan , Synnergren Mats , Baghaei Fariba , Jeppsson Anders
Published: January 2013

Objective

Earlier detection of coagulopathy in pediatric cardiac surgery patients.

Aim

To determine whether thromboelastometry (TEM) analysis before weaning from cardiopulmonary bypass (CPB) and hemoconcentration is predictive of post‐CPB results and whether analysis of clot firmness already after 10 min yields reliable results.

Background

Cardiac surgery with CPB induces a coagulopathy that may contribute to postoperative complications. Earlier detection increases the possibility of initiating countermeasures.

Methods/Material

Fifty‐six pediatric cardiac surgery patients were included in a prospective observational study. HEPTEM and FIBTEM clotting time (CT), clot formation time (CFT), and clot firmness after 10 min (A10) and at maximum (MCF) were analyzed during CPB and after CPB and ultrafiltration with modified rotational thromboelastometry (ROTEM®). The analyses were compared, and correlations and differences were calculated.

Results

Hemoconcentration with modified ultrafiltration increased hematocrit from 28 ± 3 to 37 ± 4% (P < 0.001). Correlation coefficients of the TEM variables during and after CPB ranged from 0.61 to 0.82 (all P < 0.001). HEPTEM‐CT and HEPTEM‐MCF differed significantly but the differences were marginal. Both HEPTEM and FIBTEM A10 measurements during CPB were significantly less than MCF (P < 0.001 for both), but the correlations were highly significant (HEPTEM: r = 0.95, P < 0.001; FIBTEM: r = 0.96, P < 0.001), and the differences were predictable, with narrow confidence intervals (HEPTEM: −8.2 mm (−8.9 to −7.5); FIBTEM: −0.5 mm (−0.7 to −0.3).

Conclusion

The results suggest that intraoperative TEM analyses can be accelerated by analyzing HEPTEM/FIBTEM on CPB before hemoconcentration and by analyzing clot firmness already after 10 min.
Africa's Statistical Tragedy
Authors: Devarajan Shantayanan
Published: January 2013

While Africa may have overcome its growth tragedy, it is facing a statistical tragedy, in that the statistical foundations of the recent growth in per‐capita GDP and reduction in poverty are quite weak. In many countries, GDP accounts use old methods, population censuses are out of date, and poverty estimates are infrequent and often not comparable over time. The proximate reasons have to do with weak capacity, inadequate funding, and a lack of coordination of statistical activities. But the underlying cause may be the political sensitivity of these statistics, and some donors' tendency to go around countries' own National Statistical Development Strategies (NSDS). Greater openness and transparency of statistics, and a higher profile for the NSDS, possibly with “naming and shaming” of those who try to circumvent it, may help Africans turn around their statistical tragedy.
A systematic video analysis of 69 injury cases in World Cup alpine skiing
Authors: Bere T. , Flørenes T. W. , Krosshaug T. , Haugen P. , Svandal I. , Nordsletten L. , Bahr R.
Published: January 2013

We have limited insight into how injuries occur in professional ski racing. The aim of this study was to describe the injury situations in World Cup alpine skiing. Injuries reported through the International Ski Federation Injury Surveillance System for three consecutive World Cup seasons (2006–2009) were obtained on video. In total, 69 injuries and 124 runs of matched controls were analysed by five experts to evaluate the skiing situation, skier behavior, as well as piste‐related factors. A chi‐square test (95% CI, P ≤ 0.05) was used to examine whether there was a difference between course sections regarding where the injury situation occurred. The skier was most frequently turning (n = 55) or landing from a jump (n = 13) at the time of injury. Most of the injuries to the head and upper body (96%) resulted from crashes, while the majority of knee injuries (83%) occurred while the skier was still skiing. Gate contact contributed to 30% of the injuries, while 9% occurred at contact with safety nets/material. Almost half of the injuries (46%) occurred in the final fourth of the course. A particular concern was the high contribution of inappropriate gate contact and the high‐energy impacts to the body when crashing.
An ATP synthase harboring an atypical γ–subunit is involved in ATP synthesis in tomato fruit chromoplasts
Authors: Pateraki Irini , Renato Marta , Azcón‐Bieto Joaquín , Boronat Albert
Published: January 2013

Chromoplasts are non‐photosynthetic plastids specialized in the synthesis and accumulation of carotenoids. During fruit ripening, chloroplasts differentiate into photosynthetically inactive chromoplasts in a process characterized by the degradation of the thylakoid membranes, and by the active synthesis and accumulation of carotenoids. This transition renders chromoplasts unable to photochemically synthesize ATP, and therefore these organelles need to obtain the ATP required for anabolic processes through alternative sources. It is widely accepted that the ATP used for biosynthetic processes in non‐photosynthetic plastids is imported from the cytosol or is obtained through glycolysis. In this work, however, we show that isolated tomato (Solanum lycopersicum) fruit chromoplasts are able to synthesize ATP de novo through a respiratory pathway using NADPH as an electron donor. We also report the involvement of a plastidial ATP synthase harboring an atypical γ–subunit induced during ripening, which lacks the regulatory dithiol domain present in plant and algae chloroplast γ–subunits. Silencing of this atypical γ–subunit during fruit ripening impairs the capacity of isolated chromoplast to synthesize ATP de novo. We propose that the replacement of the γ–subunit present in tomato leaf and green fruit chloroplasts by the atypical γ–subunit lacking the dithiol domain during fruit ripening reflects evolutionary changes, which allow the operation of chromoplast ATP synthase under the particular physiological conditions found in this organelle.
Quality Control and Substrate‐Dependent Downregulation of the Nutrient Transporter Fur4
Authors: Keener Justin M. , Babst Markus
Published: January 2013

Upon exposure to stress conditions, unfolded cell‐surface nutrient transporters are rapidly internalized and degraded via the multivesicular body (MVB) pathway. Similarly, high concentrations of nutrients result in the downregulation of the corresponding transporters. Our studies using the yeast transporter Fur4 revealed that substrate‐induced downregulation and quality control utilize a common mechanism. This mechanism is based on a conformation‐sensing domain, termed LID (loop interaction domain), that regulates site‐specific ubiquitination (also known as degron). Conformational alterations in the transporter induced by unfolding or substrate binding are transmitted to the LID, rendering the degron accessible for ubiquitination by Rsp5. As a consequence, the transporter is rapidly degraded. We propose that the LID–degron system is a conserved, chaperone‐independent mechanism responsible for conformation‐induced downregulation of many cell‐surface transporters under physiological and pathological conditions.
Remote damage control resuscitation and the Solstrand Conference: defining the need, the language, and a way forward
Authors: Gerhardt Robert T. , Strandenes Geir , Cap Andrew P. , Rentas Francisco J. , Glassberg Elon , Mott Jeff , Dubick Michael A. , Spinella Philip C. ,   THOR Network and RemTORN Study Groups
Published: January 2013

Damage control resuscitation (DCR) is emerging as a standard practice in civilian and military trauma care. Primary objectives include resolution of immediate life threats followed by optimization of physiological status in the perioperative period. To accomplish this, DCR employs a unique hypotensive–hemostatic resuscitation strategy that avoids traditional crystalloid intravenous fluids in favor of early blood component use in ratios mimicking whole blood.

The presence of uncontrolled major hemorrhage (UMH) coupled with a delay in access to hemostatic surgical intervention remains a primary contributor to preventable death in both combat and in many domestic settings, including rural areas and disaster sites. As a result, civilian and military emergency care leaders throughout the world have sought a means to project DCR principles forward of the traditional trauma resuscitation bay, into such remote environments as disaster scenes, rural health facilities, and the contemporary battlefield. After reflecting on experiences from past conflicts, defining current capability gaps, and examining available and potential solutions, a strategy for “remote damage control resuscitation” (RDCR) has been proposed.

In order for RDCR to progress from concept to clinical strategy, it will be necessary to define existing gaps in knowledge and clinical capability; develop a lexicon so that investigators and operators may understand each other; establish coherent research and development agendas; and execute comprehensive investigations designed to predict, diagnose, and mitigate the consequences of hemorrhagic shock and acute traumatic coagulopathy before they become irreversible.

This article seeks to introduce the concept of RDCR; to reinforce the importance of identifying and optimally managing UMH and the resulting shock state as part of a comprehensive approach to out‐of‐hospital stabilization and en route care; and to propose investigational strategies to enable the development and broad implementation of RDCR principles.
The microcirculation: linking trauma and coagulopathy
Authors: Ward Kevin R.
Published: January 2013

Survival after severe traumatic shock can be complicated by a number of pathophysiologic processes that ensue after the initial trauma. One of these is trauma‐induced coagulopathy (TIC) whose onset may occur before initial fluid resuscitation. The pathogenesis of TIC has not yet been fully elaborated, but evolving evidence appears to link severe tissue hypoxia and damage to the endothelium as key factors, which evolve into measurable structural and biochemical changes of the endothelium resulting in a coagulopathic state. This paper will provide a general review of these linkages and identify knowledge gaps as well as suggest new approaches and areas of investigation, which may both limit the development of TIC as well as produce insights into its pathophysiology. A better understanding of these issues will be necessary in order to advance the practice of remote damage control resuscitation.
Prehospital detection of traumatic coagulopathy
Authors: Hagemo Jostein S.
Published: January 2013

Increased focus on traumatic coagulopathy over the last decade has led to more aggressive use of hemostatic agents in resuscitation of the massively bleeding patient. Novel formulations of plasma factors and other therapeutics have opened for early intervention to prevent coagulopathy and may even be utilized in the prehospital setting. Careful selection of patients to receive hemostatic agents early during the resuscitation is of great importance due to the potential detrimental effects of this treatment.

Several studies have identified coagulation parameters as reliable predictors of massive transfusion, even very early after trauma. Prothrombin time international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), fibrinogen concentration, and viscoelastic tests such as thrombelastography (TEG) and rotational thrombelastometry (RoTEM) have proved to be of value in predicting massive transfusion when performed in‐hospital. PT/INR appears to be slightly more accurate than the other parameters, with a reported sensitivity of 84.8% and an area under the receiver operating curve of 0.87. Comparison studies on PT/INR, aPTT, and viscoelastic assays do suggest that caution should be taken when point‐of‐care (POC) methods, as opposed to conventional laboratory analyses, are used. Novel techniques for POC measurement of fibrinogen levels are currently being developed, and preclinical data suggest acceptable agreement with conventional methods.

A number of factors should be considered regarding the feasibility of POC tests in the prehospital environment. In addition to environmental factors such as temperature, altitude, and humidity, electromagnetic interference issues and operators' skills must be taken into account. Coagulation parameters appear to be a useful tool in identifying patients with increased risk of massive bleeding at an early stage. Further studies are needed to determine if prehospital intervention based on POC analyses improves outcome.
Risks of hemolysis due to anti‐A and anti‐B caused by the transfusion of blood or blood components containing ABO‐incompatible plasma
Authors: Berséus Olle , Boman Kjell , Nessen Shawn C. , Westerberg Lars A.
Published: January 2013

Background

The increasing use of fresh blood group O whole blood in acute trauma medicine makes it important to reevaluate the issue of hemolytic reactions related to the transfusion of ABO‐incompatible plasma.

STUDY DESIGN AND METHODS

This review summarizes and evaluates published articles and case reports concerning hemolytic reactions in connection with the transfusion of group O whole blood or blood products to nongroup O recipients.

Results

In 1945‐1986, 15 nonmilitary publications reported hemolytic transfusion reactions with group O blood/blood products. All patients recovered except for two fatalities. Late in World War II and during the Korean and Vietnam wars and onward in Iraq and Afghanistan only “low anti‐A, anti‐B titer” group O whole blood has been used as universal blood. In spite of a large number of units transfused, there are no reports of hemolytic reactions. Twenty‐five publications report hemolytic reactions after transfusion of group O platelets to nongroup O recipients. In all patients but one, the titer of the implicated A‐ or B‐antibody was >100 (saline) or >400 (antiglobulin) and all cases with an infused volume of incompatible plasma <200 mL were related to anti‐A or anti‐B antiglobulin titers >1000.

Conclusion

In emergency lifesaving resuscitation, the risk of hemolytic transfusion reactions from transfusion of group O blood to nongroup O recipients constitutes risk that is outweighed by the benefits. A low titer of anti‐A/B will minimize the risk for a hemolytic reaction, particularly if the screening is repeated after an immunization episode, e.g., blood transfusion, vaccination, or pregnancy.
A Thermohydrodynamic Sparse Mesh Model of Bump-Type Foil Bearings
Authors: Feng Kai , Kaneko Shigehiko
Published: January 2013

A numerical model for 3D thermohydrodynamic analysis of bump-type foil bearings with a sparse mesh across the air film is described. The model accounts for heat convection into cooling air, thermal expansion of the bearing components, and material property variations due to temperature rise. Deflection of the compliant foil strip, described as a link-spring structure, is coupled to the solution of the generalized Reynolds equation and the energy equation to account for the effect of foil deformation on the film thickness. The variation in bump stiffness with the thermal growth of bumps is also considered in the model. The unique airflow in foil bearings created by the top foil detachment in the subambient region is analyzed for use in modifying the thermal boundary condition. The Lobatto point quadrature algorithm is used to represent the model on a sparse mesh and thereby reduce the computational effort. The calculated bearing temperatures are in remarkable agreement with both the published test data with the use of cooling air and that without the use of cooling air. The change of bearing radial clearance due to thermal growth of the bearing components was found to significantly affect the bearing load and to be a likely cause of the obvious drop in load capacity with a rise in ambient temperature.
Extension of Fuel Flexibility in the Siemens Dry Low Emissions SGT-300-1S to Cover a Wobbe Index Range of 15 to 49 MJ/Sm3
Authors: Liu Kexin , Alexander Varkey , Sanderson Victoria , Bulat Ghenadie
Published: January 2013

The extension of gas fuel flexibility in the Siemens SGT-300 single shaft (SGT-300-1S) is reported. A successful development program has increased the capability of the Siemens Industrial Turbomachinery, Lincoln (SITL) dry low emissions (DLE) burner configuration to a fuel range covering a Wobbe index (WI) from 15 to 49 MJ/Sm3. The WI reported in this paper is at a 15 °C fuel temperature. The standard SGT-300-1S SITL DLE combustion hardware allows for gas and liquid fuels within a specified range typically associated with natural gas and diesel, respectively. The range of the WI associated with natural gas is 37–49 MJ/Sm3. Field operation of the standard production SGT-300-1S has confirmed the reliable operation with an extension to the fuels range to include processed landfill gas (PLG) from 30 to 49 MJ/Sm3. The further extension of the fuel range for the SGT-300-1S SITL DLE combustion system was achieved through high pressure testing of a single combustion system at engine operating conditions and representative fuels. The variations in the fuel heating value were achieved by blending natural gas with diluent CO2 and/or N2. Various diagnostics were used to assess the performance of the combustion system, including the measurement of combustion dynamics, temperature, fuel supply pressure, and the emissions of NOx, CO, and unburned hydrocarbons (UHCs). The results of the testing showed that the standard production burner can operate for a fuel with a WI as low as 23 MJ/Sm3, which corresponds to 35% CO2 (by volume) in the fuel. This range can be extended to 15 MJ/Sm3 (54.5% CO2 in the fuel) with only minor modification to control losses through the burner and to maintain similar fuel injection characteristics. The SITL DLE combustion system is able to cover a WI range of 15 to 49 MJ/Sm3 in two configurations. The results of testing showed a lowering in the WI, by diluting with CO2 and/or N2, so that a benefit in the NOx reduction is observed. This decrease in the WI may lead to an increased requirement of the fuel supply pressure.
Parametric Analysis of Pylon-Aided Fuel Injection in Scramjet Engines
Authors: Pohlman Mitchell R. , Greendyke Robert B.
Published: January 2013

The current study investigates means to increase the efficiency of fuel-air mixing into supersonic flow upstream of a flame holding cavity. Previous work has shown much promise in increasing the penetration and mixing of a fuel-air mixture into the freestream by injecting fuel behind small triangular pylons. The current paper examines 21 triangular pylons of varying widths, heights, and lengths with a computational fluid dynamics (CFD) performance analysis. Increasing the height of the pylons increased the penetration, flammable fuel plume area, and floor gap. Variations in pylon length had no discernible impact on the fuel-air mixing metrics. Aerodynamic loses were minimal for all pylon configurations and did not correlate to the absolute size of the pylons tested.
Ignition Delay Time and Laminar Flame Speed Calculations for Natural Gas/Hydrogen Blends at Elevated Pressures
Authors: Brower Marissa , Petersen Eric L. , Metcalfe Wayne , Curran Henry J. , Füri Marc , Bourque Gilles , Aluri Naresh , Güthe Felix
Published: January 2013

Applications of natural gas and hydrogen co-firing have received increased attention in the gas turbine market, which aims at higher flexibility due to concerns over the availability of fuels. While much work has been done in the development of a fuels database and corresponding chemical kinetics mechanism for natural gas mixtures, there are nonetheless few if any data for mixtures with high levels of hydrogen at conditions of interest to gas turbines. The focus of the present paper is on gas turbine engines with primary and secondary reaction zones as represented in the Alstom and Rolls Royce product portfolio. The present effort includes a parametric study, a gas turbine model study, and turbulent flame speed predictions. Using a highly optimized chemical kinetics mechanism, ignition delay times and laminar burning velocities were calculated for fuels from pure methane to pure hydrogen and with natural gas/hydrogen mixtures. A wide range of engine-relevant conditions were studied: pressures from 1 to 30 atm, flame temperatures from 1600 to 2200 K, primary combustor inlet temperature from 300 to 900 K, and secondary combustor inlet temperatures from 900 to 1400 K. Hydrogen addition was found to increase the reactivity of hydrocarbon fuels at all conditions by increasing the laminar flame speed and decreasing the ignition delay time. Predictions of turbulent flame speeds from the laminar flame speeds show that hydrogen addition affects the reactivity more when turbulence is considered. This combined effort of industrial and university partners brings together the know-how of applied as well as experimental and theoretical disciplines.
Application of Eulerian–Lagrangian Approach to Gas-Solid Flows in Interior Ballistics
Authors: Sung Hyung-Gun , Jang Jin-Sung , Roh Tae-Seong
Published: January 2013

In a gun system, polydisperse phenomenon may occur due to the local combustion by an igniter system during the firing process. The Eulerian–Eulerian approach still lacks the capability of describing particle mixing under given conditions. A detailed insight of the interior ballistics must be predicted for the better safety and the lower cost at the development stage. The multiphase particle in cell (MP-PIC) model based on the Eulerian–Lagrangian approach, known to be more efficient than the conventional Eulerian–Lagrangian approach, has been initially applied for the simulation of the interior ballistics. A good efficiency with the MP-PIC model has been obtained in terms of the computational cost. The axisymmetric numerical code with the MP-PIC model has been developed for two-dimensional analysis of the interior ballistics. As part of the verification process for the code, several test computations have been performed: sod shock tube, free piston motion problem, and virtual gun calculated by IBHVG2 code. The code has become reliable with well-agreed results with the comparison data. Additionally, a numerical model for the orifices to describe the vent holes of the igniter on the coarse grid has been developed with the lumped parameter method used in the IBHVG2. Based on the model, the pressure behavior in the gun chamber according to the igniter length has been investigated. The computational results have shown that the negative differential pressure occurs clearly when the igniter is sufficiently short.
Numerical Simulation and Analysis of the Muzzle Flow During the Revolving Barrel Gun Firing
Authors: Yu Wei , Zhang Xiaobing
Published: January 2013

The revolving barrel gun is the principal component of the close-in weapons system (CIWS) that provides important terminal defense against anti-ship cruise missiles that have penetrated fleet defenses. The muzzle flow field of the revolving barrel firing is extraordinarily complex. The 3D computational model was formulated to illustrate the details of the flow field produced by the revolving barrel gun firing. The algorithm of a second order monotone upstream-centered schemes (MUSCL) approach with the advection upstream splitting method (AUSM) solver was used to simulate the high pressure muzzle flow field. The interior ballistic process was coupled with the simulation. The predicted muzzle velocity and maximum bore pressure were in good agreement with those measured in gun firing. Moreover, the muzzle flow field was obtained during the revolving barrel firing and was subsequently analyzed. The maximum lateral velocity of the first and second projectile fired was about 1.6 and 3.8 m/s.
Investigation of a Nickel-Aluminum Reactive Shaped Charge Liner
Authors: Church Philip , Claridge R. , Ottley P. , Lewtas I. , Harrison N. , Gould P. , Braithwaite C. , Williamson D.
Published: January 2013

A nickel/aluminum (NiAl) reactive powder system has been investigated to determine its mechanical properties under quasi-static and high rate compression to understand its deformation behavior. A shock recovery system has been used to define shock reaction thresholds under a triaxial loading system. Two nickel/aluminum (NiAl) shaped charge liners have been fired into loose kiln dried sand to determine whether the jet material reacts during the formation process. A simple press tool was developed to press the liners from a powder mixture of nickel and aluminum powder and a simple conical design was used for the liner. The shaped charge jet particles were recovered successfully in the sand and subjected to a detailed microstructural analysis. This included X-ray diffraction (XRD) and optical and electron microscopy on selected particles. The analysis demonstrated that intermetallic NiAl was detected and all the aluminum was consumed in the particles examined. In addition, different phases of NiAl were detected as well as silicon oxide in the target material. There was also some evidence that the aluminum had melted along with evidence of a dendritic microstructure. This is the clearest evidence that the shaped charge jet material has reacted during the formation process. Simulations have been performed using the GRIM Eulerian hydrocode to compare with flash X-rays of the jet.
Innovative Technologies for Controlled Fragmentation Warheads
Authors: Villano Domenico , Galliccia Francesco
Published: January 2013

The purpose of this paper is to verify the applicability of innovative technologies for manufacturing controlled fragmentation warheads, with particular attention paid to guided ammunition. Several studies were conducted by the authors during the warhead development of DART and Vulcano family munitions. The lethality of the guided munitions can be considerably increased with controlled fragmentation warheads. This increase can compensate a lower payload of the guided munitions. After introducing the concept of warhead and its natural fragmentation, the paper describes both the elements of fracture mechanics related to the fragmentation and the state of the art of controlled fragmentation. A preliminary evaluation of controlled fragmentation technologies is illustrated along with the numerical models developed for predicting the natural and controlled fragmentations. The most promising technologies are presented in detail and the features of the warheads used for the experiments are defined. A description of the entire experimental phase is provided, including results of arena tests, data analysis and revision of numerical models. The applicability of some innovative technologies for controlled fragmentation warheads is fully demonstrated. Two technologies in particular, the laser microdrilling and the double casing solution, provide a high increase of the reference warhead lethality.
Impact Behavior of Hybrid Glass/Carbon Epoxy Composites
Authors: Pérez-Martín M. J. , Enfedaque A. , Dickson W. , Gálvez F.
Published: January 2013

The high velocity impact performance in hybrid woven carbon and S2 and E glass fabric laminates manufactured by resin transfer molding (RTM) was studied. Specimens with different thicknesses and glass-fiber content were tested against 5.5 mm spherical projectiles with impact velocities ranging from 300 to 700 m/s to obtain the ballistic limit. The resulting deformation and fracture micromechanisms were studied. Several impacts were performed on the same specimens to identify the multihit behavior of such laminates. The results of the fracture analysis, in conjunction with those of the impact tests, were used to describe the role played by glass-fiber hybridization on the fracture micromechanisms and on the overall laminate performance under high velocity impact.
Lars von Trier’s Antichrist, the Bible, and Docetic Masculinity
Authors: Buch-Hansen Gitte
Published: January 2013

Lars von Trier’s Antichrist (2009) has been criticised by feminists for its perceived misogyny. This interpretation ignores the long afterlife of the biblical figure of the Antichrist, which is more complex than its traces in contemporary popular culture would suggest.  Reading the film into the reception history of the Antichrist, drawing on both contemporary scholars and Friedrich Nietzsche—whose virulent critique of Christianity, Der Antichrist, has long been on the director’s bedside table—I argue that von Trier uses the figure to paint a scathing, even shocking, critique of masculinity as inscribed in the creeds of the early Church. The three interrelated poles of my analysis—the biblical, the aesthetic and the Nietzschean—all point in the same direction: Antichrist is not a film about the dangerous female psyche, but about a masculinity that has gone astray—or, to borrow a term from theological discourse, become "docetic."
David and Jonathan between Athens and Jerusalem
Authors: Harding James E.
Published: January 2013

This article seeks to explain what made it possible for modern biblical scholars to ask whether the relationship between David and Jonathan in 1-2 Samuel should be regarded as sexual. The answer is to be found in the way the David and Jonathan narrative was read in the nineteenth century alongside passages in Greek and Roman texts that refer to analogous pairs of friends who had already become, or were on their way to becoming, tropes for homoeroticism.