bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses, Crystal Structures, and Thermal Stabilities of Polymorphs of Cr(thd)3
Authors: Ahmed Mohammed A. K. , Fjellvåg Helmer , Kjekshus Arne , Birkedal Renie K. , Norby Poul , Wragg David S. , Gupta Nalinava Sen 
Published: August 2010

AbstractThe syntheses, crystal structures, and thermal stabilities of six polymorphs of Cr(thd)3 [(thd)– = anion of H(thd) = C11H20O2 = 2,2,6,6‐tetramethylheptane‐3,5‐dione] were studied using X‐ray diffraction and differential scanning calorimetry. Compound 1 is thermodynamically stable below ca. 110 °C and forms plate‐shaped crystals [a = 9.927(5), b = 18.010(5), c = 21.427(5) Å, and β = 95.461(5)° at 295 K; space group C2/c]. Its crystal structure is isotypic with Mn(thd)3. Polymorph 4 is metastable to 1, and the only way to prepare 4 appears to be by precipitation from solution. Crystals of 4 are needle shaped [a = 28.54(3), b = 19.14(2), c = 21.92(2) Å, and β = 97.31(2)° at 295 K; space group C2/c] and this structure is isotypic with monoclinic Co(thd)3. Modifications 2, 2*, and 5 also appear as needle‐shaped crystals [orthorhombic: a = 18.97(7), b = 18.69(7), and c = 10.62(5) Å for 2 and tetragonal: a = b = 18.93(5) and c = 10.57(4) Å for 5, both at 110 K]. Crystals of 2 and 5 have limited lifetime, which depends on storage temperature and exposure to X‐rays. The conversion sequence is: 5 → 2 → 1, where the first step takes 3 to 4 h and the second some 20 h. Attempts to establish detailed accounts of the orthorhombic Co(thd)3‐type structure of 2 and 2* by SXD were unsuccessful due to disorder. The structural distinction between 2 and 2* appears to be associated with rotational disorder among the Cr(thd)3 molecules. 2* and 3 are high‐temperature modifications with stability range ca. 155–200 and ca. 200–235 °C, respectively [Cr(thd)3 melts at ca. 235 °C]. Quenched 2* can be retained as metastable at room temp. for some weeks, whereas 3 is not quenchable. High‐temperature PXD data show that 3 is cubic [a = 13.357(4) Å at 225 °C; with strong rotational disorder of the molecules]. There are only minor variations in bond lengths and angles between 1 and 4 or from 100 to 295 K, and disorder is limited.
Lipid Profiling Reveals Tissue‐Specific Differences for Ethanolamide Lipids in Mice Lacking Fatty Acid Amide Hydrolase
Authors: Kilaru Aruna , Isaac Giorgis , Tamura Pamela , Baxter David , Duncan Scott R. , Venables Barney J. , Welti Ruth , Koulen Peter , Chapman Kent D. 
Published: August 2010

AbstractN‐Acylethanolamines (NAE) are fatty acid derivatives, some of which function as endocannabinoids in mammals. NAE metabolism involves common (phosphatidylethanolamines, PEs) and uncommon (N‐acylphosphatidylethanolamines, NAPEs) membrane phospholipids. Here we have identified and quantified more than a hundred metabolites in the NAE/endocannabinoid pathway in mouse brain and heart tissues, including many previously unreported molecular species of NAPE. We found that brain tissue of mice lacking fatty acid amide hydrolase (FAAH−/−) had elevated PE and NAPE molecular species in addition to elevated NAEs, suggesting that FAAH activity participates in the overall regulation of this pathway. This perturbation of the NAE pathway in brain was not observed in heart tissue of FAAH−/− mice, indicating that metabolic regulation of the NAE pathway differs in these two organs and the metabolic enzymes that catabolize NAEs are most likely differentially distributed and/or regulated. Targeted lipidomics analysis, like that presented here, will continue to provide important insights into cellular lipid signaling networks.
Post‐ischemic administration of nimodipine following focal cerebral ischemic‐reperfusion injury in rats alleviated excitotoxicity, neurobehavioural alterations and partially the bioenergetics
Authors: Babu Chidambaram Saravana , Ramanathan Muthiah 
Published: August 2010

AbstractThe present study focuses on the temporal calcium significance in middle cerebral artery occluded (2 h ischemia)–reperfused (70 h reperfusion) rats treated with nimodipine (NM) through concurrent measurements of excitotoxicity, bioenergetics and neurobehavioural paradigms. Further, the suitable therapeutic time window of calcium channel antagonism in stroke was also ascertained. NM (5 mg/kg, i.p.) was administered at pre (30 min before the induction of ischemia), during (1 h following occlusion of MCA) and post‐ischemic (3 h after begin of reperfusion) states. The magnitude of neuroprotection in terms of excitotoxicity (glutamate, glutamine synthetase, Na+K+ATPase), bioenergetics (ATP, NAD+) and neurobehavioural paradigms (neurological score and open field exploratory behaviour) were measured and compared to ensure the therapeutic time‐window of NM in stroke. Middle cerebral artery occlusion‐reperfusion (MCAO/R) was found to elevate glutamate, glutamine synthetase levels and deplete Na+K+ATPase activity in the vehicle treated group (IR group). Significant decrease in bioenergetics such as ATP and NAD+ levels was also observed. Further, IR group demonstrated grievous oxidative stress (increase in lipid peroxidation, protein carbonyl content, nitrite/nitrate levels and decrease in superoxide dismutase and glutathione levels) along with anxiogenic behaviour, neurological deficits and neuronal damage and decreased nuclear to cytoplasm ratio in CA1 hippocampal region. Post‐ischemic NM administration reversed the excitotoxicity, neurobehavioural and histopathological alterations significantly, but it restored bioenergetics level in MCAO/R rats only partially.These findings were further confirmed with the combination treatment (CT) of post‐ischemic NM and pre‐ischemic memantine (MN) administration, since MN showed protective effect in the pre‐ischemic administration (Babu and Ramanathan, 2009). The failure of NM to forefend the neurodegeneration on pre‐ and during‐ischemic administration suggests that the initial phase damages in ischemic‐reperfusion (IR) might be mediated through other mechanism(s) such as glutamergic overstimulation or reverse operation of glutamate transporters. From the present study, it is concluded that calcium plays a crucial role in post‐ischemic status and the suitable therapeutic time window of calcium antagonism is the post‐ischemic state.
The relationship between controlled joint torque and end-effector force in underactuated robotic systems
Authors: Park Jaeheung 
Published: August 2010

SUMMARYThe generalized Jacobian matrix was introduced for dealing with end-effector control in space robots. One of the applications of this Jacobian is to be used in Jacobian transpose control to generate joint torques given end-effector position error. It would be misleading, however, to consider the transpose of this Jacobian as a mapping from end-effector force/moment to controlled joint torques for underactuated systems or floating base robots. This paper explains why it does not represent the mapping and provides a simple example. Later, the correct mapping is provided using the dynamically consistent Jacobian inverse and then a method to compute the actuated-joint torques is explained given the desired end-effector force. Finally, the effect of using the generalized Jacobian in the Jacobian transpose control is analyzed.
The origin of the vertebrate skeleton
Authors: Pivar Stuart 
Published: August 2010

AbstractThe anatomy of the human and other vertebrates has been well described since the days of Leonardo da Vinci and Vesalius. The causative origin of the configuration of the bones and of their shapes and forms has been addressed over the ensuing centuries by such outstanding investigators as Goethe, Von Baer, Gegenbauer, Wilhelm His and D'Arcy Thompson, who sought to apply mechanical principles to morphogenesis. However, no coherent causative model of morphogenesis has ever been presented.This paper presents a causative model for the origin of the vertebrate skeleton, based on the premise that the body is a mosaic enlargement of self-organized patterns engrained in the membrane of the egg cell. Drawings illustrate the proposed hypothetical origin of membrane patterning and the changes in the hydrostatic equilibrium of the cytoplasm that cause topographical deformations resulting in the vertebrate body form.
Constraints on the evolution of social institutions and their implications for information flow
Authors: DUNBAR R. I. M. 
Published: August 2010

Abstract:Human communities and ego-centric social networks have a distinct size that reflects a generic relationship between relative neocortex volume and social group size that is characteristic of primates in general (the ‘social brain hypothesis’). Human networks are structured into layers that reflect both differences in the frequency of contact and levels of emotional closeness. The rate of decay in the frequency of contact across network layers is very steep, and we might expect this to have a very significant effect on the likelihood of Ego finding out some novel fact when information flow is limited to face-to-face interaction. I use an analytical model parameterized by these contact frequencies to show that there may be little advantage in having a network larger than ~150 for the purposes of information exchange. I then present a Monte Carlo simulation model to show that structure significantly impedes the rate of information flow in structured communities.
A synopsis of urban violence in South Africa
Authors: Abrahams David 
Published: August 2010

AbstractOn 27 April 1994, all South Africans were permitted to vote for the first time, signalling the birth of a democratic state built on a constitutional democracy. Yet the wrath of gang-related activities in townships and other urban areas was clearly visible, as was the xenophobic violence that shocked the world. Very often the vast majority of victims have been innocent civilians, and especially women and children. This article gives an overview of the various forms of violence in South Africa and also briefly considers the state's responses to them within the various legal frameworks.
Pulmonary Vein Stenosis by Ostial Irrigated‐Tip Ablation:
Authors: PÜRERFELLNER HELMUT , CIHAL RUDOLF , AICHINGER JOSEF , MARTINEK MARTIN , NESSER HANS JOACHIM 
Published: August 2010

Monitoring and Prediction of PV Stenosis.
Introduction: The incidence of pulmonary vein (PV) stenosis and its time course for ostial trigger elimination in paroxysmal atrial fibrillation (PAF) is uncertain. In addition, the clinical value of serial computed tomographic (CT) scanning of the PV ostia and the predictive value of energy requirements for radiofrequency ablation have yet to be established. Methods and Results: We performed irrigated‐tip ablation in 37 patients with drug‐resistant PAF. Serial spiral CT scans were taken prospectively in 34 patients the day before the procedure, at prehospital discharge, and at 3‐ and 6‐month follow‐up. Using a clock model, energy requirements were analyzed for every segment of the PV circumference. One hundred fifteen PVs were targeted in 57 procedures. Compared to baseline, 7 (6.08%) of 115 PV showed minor (<50%) PV stenosis. Two severe (>90%) PV stenoses (1.73%) were detected with a mean follow‐up of 275 ± 100 days. Luminal narrowing occurred most frequently in the left inferior PV (6/9 stenosed PV). Minor stenosed PVs showed their maximal luminal regression within the 3‐month follow‐up. Two of two PVs with narrowing >50% at 3 months progressed to high‐grade stenosis. Analysis of delivered energy showed no significant correlation with the degree of stenosis. However, for the left inferior PV, more energy was applied in the superior segment of a stenotic PV (6697 ± 930 J vs 3555 ± 380 J, P = 0.005). Conclusion: Assessment of PV diameter by serial spiral CT scanning shows a low incidence of severe stenosis. The left inferior PV is at higher risk. Minor stenosed PV showed no progression after 3 months. Occurrence of stenosis tended to be related to the amount of energy delivered. (J Cardiovasc Electrophysiol, Vol. 14, pp. 158‐164, February 2003)
New Cryotechnology for Electrical Isolation of the Pulmonary Veins
Authors: AVITALL BOAZ , URBONIENE DALIA , ROZMUS GRZEGORZ , LAFONTAINE DAN , HELMS RAY , URBONAS ARVYDAS 
Published: August 2010

Introduction: Creation of radiofrequency lesions to isolate the pulmonary veins (PV) and ablate atrial fibrillation (AF) has been complicated by stenosis of the PVs. We tested a cryoballoon technology that can create electrical isolation of the PVs, with the hypothesis that cryoenergy will not result in PV stenosis.
Methods and Results: Lesions were created in 9 dogs (weight 31–37 kg). Cryoenergy was applied to the PV‐left atrial (LA) interface. Data collected before and after ablation included PV orifice size, arrhythmia inducibility, electrogram activity, and pacing threshold in the PVs. Tissue examination was performed immediately after ablation in 3 dogs and after 3 months (4.8 ± 1.0) in 6 dogs. After ablation there was no localized P wave activity in the ablation zone and no LA‐PV conduction. Before ablation, the pacing threshold was

1.9 ± 1.1 mA

in each PV. After ablation, the pacing threshold increased significantly to

7.2 ± 1.8 mA

, or capture was not possible. Burst pacing did not induce any sustained arrhythmias. Most dogs had hemoptysis during the first 24 to 48 hours. Acute tissue examination revealed hemorrhagic injury of the atrial‐PV junction that extended into the lung parenchyma. After recovery, the lesions were circumferential and soft with no PV stenosis. Histologic examination revealed fibrous tissue with no PV‐LA interface thickening.
Conclusion: This new cryoballoon technology effectively isolates the PVs from LA tissue. No PV stenosis was noted. Acute tissue hemorrhage and hemoptysis are short‐term complications of this procedure. After 3 months of recovery, cryoablated tissue exhibits no collagen or cartilage formation.
(J Cardiovasc Electrophysiol, Vol. 14, pp. 281‐286, March 2003)
Anatomy of the Pulmonary Veins in Patients with Atrial Fibrillation and Effects of Segmental Ostial Ablation Analyzed by Computed Tomography
Authors: SCHARF CHRISTOPH , SNEIDER MICHAEL , CASE IAN , CHUGH AMAN , LAI STEVE W.K. , PELOSI FRANK , KNIGHT BRADLEY P. , KAZEROONI ELLA , MORADY FRED , ORAL HAKAN 
Published: August 2010

Pulmonary Vein Anatomy.
Introduction: The anatomic arrangement of pulmonary veins (PVs) is variable. No prior studies have quantitatively analyzed the effects of segmental ostial ablation on the PVs. The aim of this study was to determine the effect of segmental ostial radiofrequency ablation on PV anatomy in patients with atrial fibrillation (AF). Methods and Results: Three‐dimensional models of the PVs were constructed from computed tomographic (CT) scans in 58 patients with AF undergoing segmental ostial ablation to isolate the PVs and in 10 control subjects without a history of AF. CT scans were repeated approximately 4 months later. PV and left atrial dimensions were measured with digital calipers. Four separate PV ostia were present in 47 subjects; 3 ostia were present in 2 subjects; and 5 ostia were present in 9 subjects. The superior PVs had a larger ostium than the inferior PVs. Patients with AF had a larger left atrial area between the PV ostia and larger ostial diameters than the controls. Segmental ostial ablation resulted in a 1.5 ± 3.2 mm narrowing of the ostial diameter. A 28% to 61% focal stenosis was present 7.6 ± 2.2 mm from the ostium in 3% of 128 isolated PVs. There were no instances of symptomatic PV stenosis during a mean follow‐up of 245 ± 105 days. Conclusion: CT of the PVs allows identification of anatomic variants prior to catheter ablation procedures. Segmental ostial ablation results in a significant but small reduction in ostial diameter. Focal stenosis occurs infrequently and is attributable to delivery of radiofrequency energy within the PV. (J Cardiovasc Electrophysiol, Vol. 14, pp. 150‐155, February 2003)
Detection of Proarrhythmia in the Female Rabbit Heart:
Authors: HONDEGHEM LUC M. , LU HUA RONG , ROSSEM KOEN van , De CLERCK FRED 
Published: August 2010

Introduction:Reliable detection of drug‐induced proarrhythmia, especially the potential for polymorphic ventricular tachycardia, is of great importance in the development of new compounds that are safe for the heart and was evaluated in a blinded study.Methods and Results:In 142 female rabbits, the monophasic action potential was used to determine intraventricular conduction, action potential duration (APD), triangulation (APD30to APD90), reverse use‐dependence, instability and presence of chaotic behavior, early afterdepolarizations, torsades de pointes (TdP), and ventricular fibrillation. In addition, 31 coded drugs were tested in a blinded fashion in another 150 hearts. Prototype cardiovascular agents [quinidine (IA), lidocaine (IB), flecainide (IC), propranolol (II), sotalol (IIIB), amiodarone (IIIAB) and verapamil (IV)] were correctly characterized in terms of their effects upon conduction and APD. Agents documented in clinical practice to have proarrhythmic potential (droperidol, sotalol, mibefradil, bepridil, lidoflazine, ketanserin, sertindole, terfenadine, haloperidol, astemizole, cisapride, ziprasidone, lubeluzole, dofetilide, quinidine, ibutilide) were identified as such. Pimozide is reported to rarely produce TdP and was also found to elicit Class III action with few adverse effects. Equally important, agents believed not to be proarrhythmic (two solvents, atenolol, propranolol, fenoximone, cetirizine, verapamil, sildenafil, lidocaine, diltiazem) were identified as having no proarrhythmic activity.Conclusion:The SCREENIT method properly characterized and quantified prototype cardiovascular drugs and correctly identified proarrhythmic noncardiovascular agents of various mechanisms, but it did not produce false‐positive results.(J Cardiovasc Electrophysiol, Vol. 14, pp. 287‐294, March 2003)
A Multicenter Experience with Novel Implantable Cardioverter Defibrillator Configurations in the Pediatric and Congenital Heart Disease Population
Authors: STEPHENSON ELIZABETH A. , BATRA ANJAN S. , KNILANS TIMOTHY K. , GOW ROBERT M. , GRADAUS RAINER , BALAJI SESHADRI , DUBIN ANNE M. , RHEE EDWARD K. , RO PAMELA S. , THØGERSEN ANNA M. , CECCHIN FRANK , TRIEDMAN John K. , WALSH EDWARD P. , BERUL CHARLES I. 
Published: August 2010

Introduction: In pediatric and congenital heart disease patients, transvenous ICD implantation may be limited secondary to patient size, venous, or cardiac anatomy. Epicardial patches require a thoracotomy, and may lead to a restrictive pericardial process. Because of these issues, we have explored novel ICD configurations. Methods: Retrospective review at 10 centers implanting ICDs without a transvenous shocking coil or epicardial patches. Results: Twenty‐two patients underwent implant at a mean age of 8.9 years (range: 0.3–43.5), with a mean weight of 25.5 kg (range: 5.2–70). Diagnoses included complex CHD, intracardiac tumors, cardiomyopathy, idiopathic VT, LV noncompaction, and long QT syndrome. Three configurations were used: subcutaneous array, a transvenous design ICD lead placed on the epicardium, or a transvenous design ICD lead placed subcutaneously. Difficulties were found at implant in 8 patients: 4 had difficulty inducing VT/VF, and 4 had high DFTs. Over a mean follow‐up of 2.2 years (range: 0.2–10.5), 7 patients had appropriate shocks. Inappropriate shocks occurred in 4 patients. System revisions were required in 7 patients: 2 generator changes (in 1 patient), 3 pace‐sense lead replacement, 1 additional subcutaneous coil placement due to increased DFT, 1 upgrade to a transvenous system, and 1 revision to epicardial patch system. Conclusions: ICD implantation can be performed without epicardial patches or transvenous high‐energy leads in this population, using individualized techniques. This will allow ICD use in patients who have intracardiac shunting or are deemed too small for transvenous ICD leads. The long‐term outcome and possible complications are as yet unknown in this population, and they should be monitored closely with follow‐up DFTs.
Incidence and Location of Focal Atrial Fibrillation Triggers in Patients Undergoing Repeat Pulmonary Vein Isolation:
Authors: Gerstenfeld Edward P. , Callans David J. , Dixit Sanjay , Zado Erica , Marchlinski Francis E. 
Published: August 2010

Introduction: The etiology of atrial fibrillation (AF) recurrences after pulmonary vein (PV) isolation is not well described. The aim of this study was to examine the reason for recurrent AF in patients undergoing a repeat attempt at AF trigger ablation. Methods and Results: Patients with recurrent AF more than 1 month after ablation returned for repeat mapping and ablation. A circular mapping catheter was advanced to each previously targeted PV ostium to determine if the PV was still electrically isolated. Ectopy then was provoked with isoproterenol (up to 20 μg/min), burst pacing, and pacing into AF followed by cardioversion. The location of ectopy triggering atrial premature depolarizations (APDs) or AF was noted. Of 226 patients who underwent ablation of AF triggers, 34 (8 women and 26 men; age 56 ± 10 years) with recurrent AF returned for a repeat procedure 207 ± 183 days after the first procedure. There were 84 previously completely isolated PVs in these 34 patients. Thirty‐three (39%) of 84 previously isolated PVs were still completely isolated at the time of the second procedure. Fifty‐one PVs (61%) had evidence of recovered PV potentials. Fifty triggers of APDs and AF (n = 30) or APDs only (n = 20) were identified in these 34 patients. The majority of triggers [27/50 (54%)] originated from previously targeted PVs. Sixteen triggers [16/50 (32%)] originated from previously nontargeted PVs. Conclusion: The majority of AF recurrences originate from previously isolated PVs. One third of recurrent triggers originated from PVs that were not targeted during the initial ablation session. Although empiric isolation of all PVs may reduce recurrences, strategies to ensure ostial PV isolation and to prevent recurrent PV conduction after ablation should have the greatest impact on reducing AF recurrence. (J Cardiovasc Electrophysiol, Vol. 14, pp. 685‐690, July 2003)