bluuebunny/crossref_metadata_2025_split huggingface dataset:
LDA + U and hybrid functional calculations for defects in ZnO, SnO2, and TiO2
Authors: Janotti Anderson , Van de Walle Chris G. 
Published: December 2010

AbstractWe describe and compare defect calculations based on density functional theory within the local density approximation (LDA), the orbital‐dependent LDA + U, and using hybrid functionals. Limitations of the LDA in describing defect formation energies and transition levels are discussed, followed by corrections based on the LDA + U, and the use of the hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE). The band‐gap error in LDA leads to large uncertainties not only in defect transition levels but also in formation energies.LDA + U provides a partial correction to the band gap and, when combined with LDA, provides an accurate method for predicting transition levels. Formation energies obtained from the LDA + U/LDA approach depend on the ability of LDA + U to correctly describe the position of the band edges on an absolute energy scale. Although computationally demanding, HSE is demonstrated to be a reliable method for predicting structure and electronic properties of semiconductors, including transition levels and formation energies of defects.
Magnetic field induced thermal effect of phonons in graphene
Authors: Peng Feng 
Published: December 2010

AbstractWe investigate the effect of a magnetic field on the thermal properties of phonons in graphene. We calculate the heat capacity of the phonons using a generating functional technique, and find a new phenomenon that a staircase‐like behaviour appears in the change of the phonon heat capacity as well as the thermal conductivity with the temperature. The width and height of each step are related to the magnetic field and the temperature. This may provide a scheme of controlling the thermal properties of graphene by a weak magnetic field.
Catalytic oxidation of CO on Ir(100)
Authors: Erikat I. A. , Hamad B. A. , Khalifeh J. M. 
Published: December 2010

AbstractDensity functional theory (DFT) calculations are performed to investigate the CO oxidation on Ir(100) surface at different CO coverages, 0.125, 0.25, and 0.5 monolayers (ML). The reaction pathway and transition state (TS) are determined using constrained minimization and nudged elastic band (NEB) methods. We found that the CO molecule is significantly more mobile toward O atoms, which causes a weakening of the Ometal bond. The increase of CO coverage leads to a decrease in the activation energy of the reaction and an increase of OaCO distance where O coverage is kept at 0.25 ML.
Stereo vision–based navigation for autonomous surface vessels
Authors: Huntsberger Terry , Aghazarian Hrand , Howard Andrew , Trotz David C. 
Published: December 2010

AbstractThis paper describes a stereo vision–based system for autonomous navigation in maritime environments. The system consists of two key components. The Hammerhead vision system detects geometric hazards (i.e., objects above the waterline) and generates both grid‐based hazard maps and discrete contact lists (objects with position and velocity). The R4SA (robust, real‐time, reconfigurable, robotic system architecture) control system uses these inputs to implement sensor‐based navigation behaviors, including static obstacle avoidance and dynamic target following. As far as the published literature is concerned, this stereo vision–based system is the first fielded system that is tailored for high‐speed, autonomous maritime operation on smaller boats. In this paper, we present a description and experimental analysis of the Hammerhead vision system, along with key elements of the R4SA control system. We describe the integration of these systems onto a number of high‐speed unmanned surface vessels and present experimental results for the combined vision‐based navigation system. © 2010 Wiley Periodicals, Inc.
A learning perspective on intraorganizational knowledge spill‐ins
Authors: Oldroyd James B. , Gulati Ranjay 
Published: December 2010

AbstractThis exploratory study examines the role of intraorganizational knowledge spill‐ins in the process of inferential learning. Drawing on the notions of knowledge reliability (the creation of shared meanings) and validity (the understanding of cause and effect), we explore how organizations learn inferentially in dynamic environments, where active experimentation rather than past experience is the underlying basis for learning. We find that intraorganizational knowledge spill‐ins transfer heuristics crafted by one unit under local conditions of reliability and validity to other units, where they are reinterpreted and repurposed. Intraorganizational knowledge spill‐ins emerge as a mechanism through which reliability and validity are enhanced for organizational learning. Copyright © 2010 Strategic Management Society.
Spillovers, spill‐ins, and strategic entrepreneurship: America's first commercial jet airplane and Boeing's ascendancy in commercial aviation
Authors: Kotha Suresh 
Published: December 2010

AbstractBuilding on recent studies on knowledge spillovers and spill‐ins, this study traces the post‐World War II knowledge spillovers during the early days of the modern commercial aviation industry. It examines the impact these spillovers had on opportunity‐ and advantage‐seeking behaviors (i.e., strategic entrepreneurship) of the leading American incumbents: Douglas, Lockheed, Boeing, and a new entrant, de Havilland of Great Britain. Specifically, it highlights the processes triggered by knowledge spillovers that led to internal knowledge generation, innovations and, ultimately, Boeing's ascendancy in commercial aviation. It shows that knowledge spillovers and the concomitant processes they trigger can provide a powerful lens for studying opportunity‐ and advantage‐seeking behavior in incumbents and entrants and the resultant outcomes of this dynamic. This study sensitizes researchers to examine the nuanced and complex interplay among knowledge generation, knowledge spillovers and spill‐ins, and strategic entrepreneurship within a specific industry context to explain performance outcomes. Copyright © 2010 Strategic Management Society.
Rigid Dimers Formed through Strong Interdigitated H‐Bonds Yield Compact 1D Supramolecular Helical Polymers
Authors: Ciesielski Artur , Stefankiewicz Artur R. , Hanke Felix , Persson Mats , Lehn Jean‐Marie , Samorì Paolo 
Published: December 2010

AbstractHierarchical self‐assembly of small abiotic molecular modules interacting through noncovalent forces is increasingly being used to generate functional structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H‐bond supramolecular architectures, especially in H‐bonded supramolecular polymers, can be achieved by using conformationally rigid molecular modules undergoing self‐assembly through strong H‐bonds. Their binding strength depends on the multiplicity of the H‐bonds, the nature of donor/acceptor pairs and their secondary attractive/repulsive interactions. Here a functionalized molecular module is described, which is capable of self‐associating through self‐complementary H‐bonding patterns comprising four strong and two medium‐strength H‐bonds to form dimers. The self‐association of these phenylpyrimidine‐based dimers through directional H‐bonding between two lateral pyridin‐2(1H)‐one units of neighboring molecules allows the formation of highly compact 1D supramolecular polymers by self‐assembly on graphite. A concentration‐dependent study by scanning tunneling microscopy at the solid–liquid interface, corroborated by dispersion‐corrected density functional studies, reveals the controlled generation of either linear supramolecular 2D arrays, or long helical supramolecular polymers with a high shape persistence.
Preoperative Vitamin D Deficiency Predicts Postoperative Hypocalcemia After Total Thyroidectomy
Authors: Kirkby‐Bott James , Markogiannakis Haridimos , Skandarajah Anita , Cowan Matthew , Fleming Bill , Palazzo Fausto 
Published: December 2010

AbstractBackgroundTransient postthyroidectomy hypocalcemia occurs in up to 30% of patients. We evaluated the effect of vitamin D deficiency on postthyroidectomy hypocalcemia.MethodsData were collected prospectively between January 2006 and March 2009. A total of 166 consecutive total thyroidectomies were analyzed regarding the relation between preoperative vitamin D3 levels and postoperative corrected calcium levels. Patients were divided into three groups dependent upon the preoperative vitamin D3 level: group 1, <25 nmol/l; group 2, 25–50 nmol/l; group 3, >50 nmol/l (conversion factor of 2.5× between nanomoles per liter and nanograms per milliliter). Hypocalcemia was defined as a postoperative calcium level <2.00 mmol/l (8 mg/dl). Hospital length of stay was recorded.ResultsThere was a difference in postoperative hypocalcemia between the three vitamin D3 groups (group 1 (32%) vs. group 2 (24%) vs. group 3 (13%). Hypocalcemia in group 1 (vit D <25 nmol/l, <10 ng/ml) was significantly more likely than in group 3 (vit D >50 nmol/l, >20 ng/ml) (P = 0.025, χ2 test. Vitamin D3 deficiency was also associated with a longer hospital stay (median stay 2 days vs. 1 day, P < 0.001, Wilcoxon rank test).ConclusionsThere is a significant difference in postoperative hypocalcemia rates between those with vitamin D levels >50 nmol/l (>20 ng/ml) and those with a level of <25 nmol/l (<10 ng/ml). Vitamin D deficiency leads to a delay in discharge owing to a higher likelihood of hypocalcemia.
Current Management of Cervical Esophageal Cancer
Authors: Tong Daniel King Hung , Law Simon , Kwong Dora Lai Wan , Wei William I. , Ng Raymond Wai Man , Wong Kam Ho 
Published: December 2010

AbstractBackgroundPharyngo‐laryngo‐esophagectomy (PLE) has been regarded as a standard treatment for cervical esophageal cancer, but the morbidity and mortality rates associated with PLE are substantial. Chemoradiation (CTRT) is widely used to treat esophageal cancer; however, its role in managing cervical esophageal cancer has not been fully elucidated. It was hypothesized that up‐front CTRT could be an effective alternative treatment option to PLE. The purpose of this study was to compare the outcomes of patients with cervical esophageal cancer treated with these two methods.MethodsPatients with cervical esophageal cancer from 1995 to 2008 were studied. Three main groups were identified: those treated with PLE, those managed with up‐front concurrent chemoradiation, and those not suitable for either PLE or chemoradiation but to whom palliative treatment was offered. The demographics, management strategies, and outcomes of these patients were studied and analyzed.ResultsA total of 107 patients were studied: 87 (81.3%) were men, and the median age was 64 years (range 17–92 years). There were 62 patients who underwent PLE as the primary treatment, 21 had up‐front chemoradiation, and the others had palliative treatment. In the PLE group, curative resection was achieved in 37 (59.7%) patients, 20 of whom had either adjuvant chemoradiation or radiotherapy. The hospital mortality rate was 7.1%. In the chemoradiation group, 10 (47.6%) had tumor down‐staging, 6 of whom achieved a clinically complete response. Among the 11 patients with poor response, 5 required salvage PLE for palliation. Chemoradiation‐associated morbidities included oral mucositis, bilateral vocal cord palsy, esophageal stricture, carotid artery blowout, and permanent hypothyroidism and hypoparathyroidism. The median survival durations of patients in the PLE and chemoradiation groups were 20 and 25 months respectively (P = 0.39).ConclusionsUp‐front chemoradiation can be an alternative therapeutic strategy to PLE. However, this method is not without drawbacks. A significant proportion also requires salvage surgery. Both PLE and chemoradiation have significant curative as well as palliative role in the management of cervical esophageal cancer and treatment should be individualized.
State of Surgery in Tropical Africa: A Review
Authors: Lavy Chris , Sauven Kathryn , Mkandawire Nyengo , Charian Meena , Gosselin Richard , Ndihokubwayo Jean Bosco , Parry Eldryd 
Published: December 2010

AbstractThis is a review of recently published literature on surgery in tropical Africa. It presents the current state of surgical need and surgical practice on the continent. We discuss the enormous burden of surgical pathology (as far as it is known) and the access to and acceptability of surgery. We also describe the available facilities in terms of equipment and manpower. The study looked at the effects of the human immunodeficiency virus, the role of traditional healers, anesthesia, and the economics of surgery. Medical training and research are discussed, as are medical migration out of Africa and the concept of task shifting, where surgical procedures are performed by others when surgeons are not available. It closes with recommendations for involvement and action in this area of great global need.
Anatomical Versus Nonanatomical Resection of Colorectal Liver Metastases: Is There a Difference in Surgical and Oncological Outcome?
Authors: Lalmahomed Zarina S. , Ayez Ninos , van der Pool Anne E. M. , Verheij Joanne , IJzermans Jan N. M. , Verhoef Cornelis 
Published: December 2010

AbstractBackgroundThe increased use of neoadjuvant chemotherapy and minimally invasive therapies for recurrence in patients with colorectal liver metastases (CLM) makes a surgical strategy to save as much liver volume as possible pivotal. In this study, we determined the difference in morbidity and mortality and the patterns of recurrence and survival in patients with CLM treated with anatomical (AR) and nonanatomical liver resection (NAR).MethodsFrom January 2000 to June 2008, patients with CLM who underwent a resection were included and divided into two groups: patients who underwent AR, and patients who underwent NAR. Patients who underwent simultaneous radiofrequency ablation in addition to surgery and patients with extrahepatic metastasis were excluded. Patient, tumor, and treatment data, as well as disease‐free and overall survival (OS) were compared.ResultsEighty‐eight patients (44%) received AR and 113 patients (56%) underwent NAR. NAR were performed for significant smaller metastases (3 vs. 4 cm, P < 0.001). The Clinical Risk Score did not differ between the groups. After NAR, patients received significantly less blood transfusions (20% vs. 36%, P = 0.012), and the hospital stay was significantly shorter (7 vs. 8 days, P < 0.001). There were no significant differences in complications, positive resection margins, or recurrence. For the total study group, estimated 5‐year disease‐free and OS was 31 and 44%, respectively, with no difference between the groups.ConclusionsOur study resulted in no significant difference in morbidity, mortality, recurrence rate, or survival according to resection type. NAR can be used as a save procedure to preserve liver parenchyma.
Outcomes for Lymph Node‐Positive Cutaneous Melanoma Over Two Decades
Authors: Martinez Steve R. , Tseng Warren H. , Young Shawn E. 
Published: December 2010

AbstractBackgroundOur aim was to demonstrate that, despite advances in treatment and surveillance of node‐positive cutaneous melanoma, rates of overall survival (OS) and melanoma‐specific survival (MSS) have not changed over the last two decades.MethodsWe used the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute to identify patients with node‐positive cutaneous melanoma. Patients were categorized by treatment era; the first era encompassed patients diagnosed from 1988 to 1999 and the second era 2000 to 2006. Multivariate Cox proportional hazards models compared rates of OS and MSS between treatment eras while controlling for known prognostic factors. We reported risks of death as hazard ratios (HR) with 95% confidence intervals (CI) and set significance at P ≤ 0.05.ResultsEntrance criteria were met by 6,868 patients, 1,631 (23.8%) treated in era I and 5,237 (76.3%) treated in era II. On multivariate analysis, era II patients did not demonstrate a significantly different risk of death from any cause (HR 0.89, CI 0.79–1.01; P < 0.08), but they did have a lower risk of melanoma‐specific mortality (HR 0.81, CI 0.71–0.93; P = 0.003) relative to their era I counterparts.ConclusionsOver nearly two decades, MSS but not OS has improved for AJCC stage III melanoma patients. Stage migration is likely responsible for any improvement in MSS among patients in the most recently diagnosed era.
Current status of endoscopic papillary balloon dilation for the treatment of bile duct stones
Authors: Aiura Koichi , Kitagawa Yuko 
Published: December 2010

AbstractBackground/purposeWhile endoscopic sphincterotomy (EST) is performed worldwide for the removal of common bile duct stones, many biliary endoscopists hesitate to regard endoscopic papillary balloon dilation (EPBD) as a standard procedure for treatment. Therefore, the aim of this review is to re‐evaluate the status of EPBD for the treatment of common bile duct stones.ResultsA major benefit of EPBD is preservation of papillary function, which is not complete but may be greater than that after EST. The disadvantages of EPBD compared with EST are that EPBD is difficult to use for the removal of larger stones because of the smaller biliary opening, it requires more frequent use of mechanical lithotripsy, and it is associated with a higher incidence of pancreatitis, although the risks of bleeding and perforation are low. Since the biliary sphincter is easily dilated with a balloon catheter, EPBD may be effective for patients with anatomic anomalies, such as after gastric bypass surgery or in the presence of a periampullary diverticulum. No standard procedure exists to reduce the risk of acute pancreatitis with EPBD.ConclusionEPBD is feasible, however, we must pursue less hazardous techniques of papillary balloon dilation. Furthermore, we must understand the benefits and limitations of EPBD and determine whether it could provide clinical benefits for long‐term complications.
Danon disease: intrafamilial phenotypic variability related to a novel LAMP‐2 mutation
Authors: Cottinet Sarah‐Louise , Bergemer‐Fouquet Anne‐Marie , Toutain Annick , Sabourdy Frédérique , Maakaroun‐Vermesse Zoha , Levade Thierry , Chantepie Alain , Labarthe François 
Published: December 2010

AbstractDanon disease is an X‐linked lysosomal disorder, characterized by hypertrophic cardiomyopathy, skeletal myopathy and mental retardation. We report a family with a novel mutation, in which the mother and her three sons were affected with various clinical presentations. A massive hypertrophy of the left ventricle was the predominant feature in the three male patients, with different degrees of severity of cardiac symptoms, from isolated palpitations to cardiac failure and sudden death. Muscle pain and weakness were also variable, but constantly associated with increased plasma CK levels. Finally, the male patients had variable degree of a mental retardation. The mother had an attenuated phenotype, limited to a mild hypertrophic cardiomyopathy with premature ventricular contractions diagnosed during her 40’s. Microscopy examination of skeletal muscle biopsy, performed in the youngest patient, demonstrated atrophic myofibers with intracytoplasmic vacuoles suggesting lysosomal glycogen storage disease. Immunohistochemistry analyses in muscle specimen showed no detectable Lysosomal‐Associated Membrane Protein‐2 (LAMP‐2), in keeping with the diagnosis of Danon disease. However, a very low expression of a shortened LAMP‐2 protein could be evidenced by Western‐blot in the patient's fibroblasts. Molecular investigations identified a novel splicing mutation (IVS6 + 1delG) in the LAMP‐2 gene. This case report highlights the intrafamilial variability of Danon disease phenotype. In this case, morphological examination of muscle biopsy, showing lysosomal storage myopathy, and immunohistochemistry analyses can provide key elements for orienting etiologic investigations.
Serum Lipoprotein(a) Levels are Greater in Female than Male Patients with Type‐2 Diabetes
Authors: Nakhjavani Manouchehr , Morteza Afsaneh , Esteghamati Alireza , Khalilzadeh Omid , Zandieh Ali , Safari Reza 
Published: December 2010

AbstractWomen with diabetes are faced with a higher risk of dyslipidemia and cardiovascular disorders than men with diabetes. We aimed to study the role of gender and menopausal status in serum Lp(a) levels in patients with type 2 diabetes. We quantified serum Lp(a) levels in a group of 477 patients with type 2 diabetes (men, premenopausal and postmenopausal women with diabetes), as well as in 105 controls. We stratified the patients into two groups of low Lp(a) levels (Lp(a) <35 mg/dl) and elevated Lp(a) levels (Lp(a) >35 mg/dl). Patients with diabetes had higher serum Lp(a) levels than the controls. Serum Lp(a) levels was significantly higher in women with diabetes than men with diabetes. Lp(a) levels did not differ between male and females in the control group. Premenopausal and postmenopausal women with diabetes did not differ significantly in serum Lp(a) levels. The odds ratio of having a serum Lp(a) level higher than 35 was 5.85 in premenopausal women with diabetes, 5.08 in postmenopausal women with diabetes, 2.41 in men with diabetes and 1.9 in the women in the control group compared to the men in the control group, after adjustment for age and BMI. This observational study clearly indicated that serum Lp(a) levels were significantly higher in women and men with diabetes. The increase in women was independent of menopause. The level of serum Lp(a) had no correlation with lipid parameters in men or women.
Hydrolysis of Fish Oil by Lipases Immobilized Inside Porous Supports
Authors: Fernández‐Lorente Gloria , Pizarro Carolina , López‐Vela Dolores , Betancor Lorena , Carrascosa Alfonso V. , Pessela Benevides , Guisan Jose M. 
Published: December 2010

AbstractA new assay was designed to measure the release of omega‐3 acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] from the hydrolysis of sardine oil by lipases immobilized inside porous supports. A biphasic system was used containing the fish oil dissolved in the organic phase and the immobilized lipase suspended in the aqueous phase. The assay was optimized by using a very active derivative of Rhizomucor miehei lipase (RML) adsorbed onto octyl‐Sepharose. Standard reaction conditions were: (a) an organic phase composed by 30/70 (v:v) of oil in cyclohexane, (b) an aqueous phase containing 50 mM methyl‐cyclodextrin in 10 mM Tris buffer at pH 7.0. The whole reaction system was incubated at 25 °C. Under these conditions, up to 2% of the oil is partitioned into the aqueous phase and most of the 95% of released acids were partitioned into the organic phase. The organic phase was analyzed by RP‐HPLC (UV detection at 215 nm) and even very low concentrations (e.g., 0.05 mM) of released omega‐3 fatty acid could be detected with a precision higher than 99%. Three different lipases adsorbed on octyl‐Sepharose were compared: Candida antarctica lipase‐fraction B (CALB), Thermomyces lanuginosa lipase (TLL) and RML. The three enzyme derivatives were very active. However, most active and selective towards polyunsaturated fatty acids (PUFA) versus oleic plus palmitic acids (a fourfold factor) was CALB. On the other hand, the most selective derivatives towards EPA versus DHA (a 4.5‐fold factor) were TLL and RML derivatives.