bluuebunny/crossref_metadata_2025 huggingface dataset:
Exact Solutions for the Incompressible Electrically Conducting Viscous Flow between two Moving Parallel Disks in Unsteady Magneto Hydrodynamic and Stability Analysis
Authors: Balagondar P.M. , Kempe Gowda M.
Published: June 2013

The main interest of the present investigation is to generate exact solutions to the steady Navier-Stokes equations for the incompressible Newtonian viscous electrically conducting fluid flow motion and stability due to disks moving towards each other or in opposite directions with a constant velocity. Making use of the analytic solution, the description of possible conditions of motion is based on the exact solutions of the Navier-Stokes equations. Both stationary and transient cases have been considered. The stability of motion is analyzed for different initial perturbations. Different types of stability were found according to whether the disks moved towards or away from each other.
Free Vibration Analysis Of Isotropic Rectangular Plates On Winkler Foundation Using Differential Transform Method
Authors: Kumar Y.
Published: June 2013

A differential transform method (DTM) is used to analyze free transverse vibrations of isotropic rectangular plates resting on a Winkler foundation. Two opposite edges of the plates are assumed to be simply supported. This semi-numerical-analytical technique converts the governing differential equation and boundary conditions into algebraic equations. Characteristic equations are obtained for three combinations of clamped, simply supported and free edge conditions on the other two edges, keeping one of them to be simply supported. Numerical results show the robustness and fast convergence of the method. Correctness of the results is shown by comparing with those obtained using other methods.
Comparison of Honey Bee Mating Optimization and Genetic Algorithm for Coordinated Design of Pss and Statcom Based on Damping of Power System Oscillation
Authors: Safari Amin , Ahmadian Ali , Aliakbar Golkar Masoud
Published: June 2013

Recently, honey bee mating optimization (HBMO) technique and genetic algorithms (GA) have attracted considerable attention among various modern heuristic optimization techniques. This paper presents the application and performance comparison of HBMO and GA optimization techniques, for coordinated design of STATCOM and PSS. The design objective is to enhance damping of the low frequency oscillations. The design problem of the controller is formulated as an optimization problem and both HBMO and GA optimization techniques are employed to search for optimal controller parameters. The performance of both optimization techniques for damping low frequency oscillations are tested and demonstrated through nonlinear time-domain simulation and some performance indices studies to different disturbances over a wide range of loading conditions. The results show that the designed controller by HBMO performs better than GA in finding the solution. Moreover, the system performance analysis under different operating conditions show that the φ based controller is superior to the C based controller.
Swinging up the Furuta Pendulum and its Stabilization Via Model Predictive Control
Authors: Seman Pavol , Rohal’-Ilkiv Boris , Juh´as Martin , Salaj Michal
Published: June 2013

This paper deals with certain options on controlling an inverted rotary pendulum also known as the Furuta pendulum. Controlling an inverted pendulum involves two stages. The first stage is the swing up of the pendulum and the second stage is its balancing in the up-right position. The paper describes two possibilities on swinging up the pendulum. First one is the classical approach based on comparing the current total (potential and kinetic) energy of the system with the energy in its stabilized up-right position. The second option uses an exponentiation operation over the pendulum position since the trend of power law function is very convenient for determining the amount of required energy to be delivered to the system. For the purposes of balancing the pendulum in the up-right position a predictive controller based on optimal control law with perturbation was proposed, which is an LQ controller with control signal corrections when constraints are exceeded. The results are illustrated by real-time experiments on a laboratory rotary inverted pendulum setup.
Predictive Synchronous Generator Excitation Control Based on Laguerre Model
Authors: Škultéty Jozef , Miklovičová Eva , Bars Ruth
Published: June 2013

In this paper the synchronous generator excitation control is designed using the model reference control approach and its predictive extension. The control objective is to satisfy requirements on the synchronous generator performances imposed by the transmission system operator. The structure of both controllers is expressed in the form of modified Laguerre network. The efficiency of the proposed control design procedure is illustrated by simulation of the 259 MVA synchronous generator of the nuclear power plant Mochovce in Slovakia.
Security Evaluation and Encryption Efficiency Analysis of RC4 Stream Cipher for Converged Network Applications
Authors: Din Riad Alaa E , Elminir Hamdy K. , Shehata Alaa R. , Ibrahim Taha R.
Published: June 2013

The trend toward converged networks where voice,IP,video and wireless are combined over the same network infrastructure offers significant - and highly attractive - benefits.But this union introduces new vulnerabilities and new opportunities to break into the network and so we need converged security.In this paper we investigate the possibility of using RC4 as a stream key generator for converged network applications.The RC4 was statistically tested against wide range of tests for inspecting the validity of the encryption,and it’s mathematically measured for encryption efficiency.All the consequent proves that RC4with suitable key length is highly secure and efficient enough to be used within the converged network.
Assessment of HHV-6 And HHV-7 in Patients After Kidney Transplantation
Authors: Folkmane Inese , Čapenko Svetlana , Ādamsone Inara , Folkmane Elizabete , Murovska Modra
Published: June 2013

Human herpesviruses HHV-6 and HHV-7 reactivation in transplantation is associated with indirect immunomodulatory effects, such as cytomegalovirus (CMV) disease, increased opportunistic infections, graft dysfunction and acute rejection (AR). In this study, we analysed the clinical and immunological outcomes in renal transplant recipients (RTR) with active HHV-6 and HHV-7 infection. Between January 2007 and December 2007, clinical, virological and immunological tests were carried out in 46 RTR. The patients were divided into three groups: with active HHV-6 infection; with active HHV-7 infection; and without infection (control). The mean follow-up was 14 ± 2.5 months. At three months after renal transplantation (RT), active CMV infection was present in 12 (26%); HHV-6 in four (8.6%); and HHV-7 in nine (19.5%) of RTR. Active ß-herpesviruses infection was not associated with more frequent AR and worsening of graft function in recipients at different times after RT. The lymphocyte subsets (CD3+; CD4+ and CD8+ cell count) were considerably lower in RTR before RT. At 3 months after RT CD19+ and CD25+ cell counts were significantly increased in the HHV-7 group compared with the control group (P < 0.05). Significant differences were not found in clinical and immunological outcomes between patients with active ß-herpesviruses infection and those without active ß-herpesviruses infection.
General Anaesthesia for Renal Transplantation in Latvia: A Critical Analysis Based on Clinical Experience
Authors: Sondore Antoņina , Ūdre Sanita , Nemme Jānis , Grašiņa Laimdota , Kruževņaka Ieva , Matulēna Inta , Rozīte Vija , Mitre Līga , Vītola Ivonna , Viskante Danuta , Aprups Juris , Berga Anita , Bormotovs Juris , Kokars Indulis
Published: June 2013

Anaesthesia methods for surgical procedures, as well as for organ transplantation, have experienced remarkable changes over the past 40 years. Cadaveric renal transplant function may be impaired by haemodynamic instability induced by anaesthesia drugs. This study aimed to analyse the safety and effectiveness of the different anaesthesia methods used for renal transplantation in Latvia since 1973, with focus on its haemodynamic effects. In this retrospective study anaesthesia chart review was conducted for 607 patients (pts), aged 17-75 yrs, ASA III/IV, undergoing renal transplantation using general anaesthesia in the following periods: 1973-1990 (stage I - 282 pts); 1991-2000 (stage II - 145 pts); 2001-2011 (stage III - 180 pts). Haemodynamic data (systolic, diastolic, mean arterial blood pressure and central venous pressure) were measured prior to premedication and induction of anaesthesia, immediately afterwards, during the surgery and up to its completion with the special attention regarding the time of graft reperfusion. The main perioperative problems of the anaesthesia methods used during stage I (barbiturates, viadril, neuroleptanalgesics, sodium oxybutyrate, halothane, nitrous oxide) was haemodynamic instability in 60% of cases and apnea due to central depression and long-time peripheral neuromuscular blockade. Two patients died due to underlying comorbid conditions, including hyperhidration and oedema pulmonum. Substantial haemodynamic changes during total intravenous anaesthesia with propofol and combined anaesthesia propofol-isoflurane (stage II) were not observed. At the time of graft reperfusion, the incidence of hypotension was slightly higher in patients anaesthetised with isoflurane than in those who received sevoflurane (stage III), but this difference was not significant (P > 0.05). Kidney functioned immediately in 75% of cases and delayed function was observed in 25% of cases in sevoflurane and isoflurane groups. The modern anaesthetic agents provide a great margin of safety during renal transplantation. Total intravenous anaesthesia with midasolam-fentanyl-propofol and general anaesthesia with propofol-isoflurane, propofol-sevoflurane can be safely used. During renal transplantation, anaesthesiologists must optimise volume status, perfusion pressure and promote survival of the renal graft.
Allogeneic Bone Marrow Multipotent Mesenchymal Stromal Cells and Polytrauma Repair: The Role of Fractionated on the Basis of Molecular Mass Red Beetroot Juice in the Prevention of Transplanted Cells Side Effects in Rats
Authors: Babarikins Dmitrijs , Krūmiņa Guntra , Paegle Irina , Amerika Diāna , Krūmiņa Zaiga , Vanags Dmitrijs , Tihomirova Tatjana
Published: June 2013

Red beetroot (Beta vulgaris) juice (RBJ) is used as a traditional medicine for treatment of anemia. It has been shown that beetroot juice decreases blood pressure, provides a protective effect on blood vessels and has antioxidant and anticancerogenic properties. In the case of polytrauma it might have beneficial effects because of its antioxidant and anti-inflammatory properties as well as antimicrobial activity. It is also well-known that RBR juice can induce undesirable side effects, e.g. flatulent stomach, nausea and other unpleasant reactions. Therefore, it seems prospective to develop red beetroot juice based on its natural compound composition free of undesirable side effects, which could then be used in combination with bone marrow multipotent mesenchymal stromal cells (BM MMSC) transplantation in the case of polytrauma. The aim of the study was to evaluate the therapeutic effect of allogeneic BM MMSC transplantation in rats with experimental polytrauma and to analyse red beetroot fractions separated on the basis of molecular weight in regard to their ingestion impact on cell transplantation efficacy. Red beet juice was fractionated by ultrafiltration (cut-off-point 20 kDa). Total phenolic compound concentration in the final product practically did not decrease. The product was tested in vitro and in vivo. Unlike native juice, fractionated RBJ in vitro suppressed BM MMSC adipogenic (60-71%, P < 0.05) and stimulated osteogenic differentiation (124%, P < 0.05). Experimental polytrauma in rats was modelled by causing three fractures and haemorrhagic shock. Animals were randomised in five groups: 1) normal control; 2) polytrauma; 3) polytrauma + i/v BM MMSC transplantation 36 h and 5 days after surgery; 4) polytrauma + fractionated RBJ administration per os 1ml/d, and 5) polytrauma + BM MMSCs + fractionated RBJ. Transplantation of allogeneic BM MMSCs in rats with experimental polytrauma stimulated bone fracture reparation, but caused plethora in viscera and dystrophic changes in lungs. Combination of BM MMSCs and fractionated RBJ resulted in better bone reparation and significant hematopoiesis stimulation.
Chronic Haemodialysis in Latvia Today and 40 Years Ago
Authors: Čerņevskis Harijs
Published: June 2013

Pēdējo 40 gadu laikā hroniska hcmodialīze Latvijā ir attīstījusies par vienu no vadošajām nieru aizstājterapijas (NAT) metodēm. 2010. gadā no kopējā pacientu skaita (442,2 pacienti uz 1 miljonu iedzīvotāju) ar hronisko hemodialīzi ārstēja 186,2 pacientus uz 1 miljonu iedzīvotāju. Rakstā analizēti NAT pacientu dati (dzimums, vecums, primārā nieru diagnoze, NAT veids), uzsākot NAT (incidence) un stāvoklis uz 2010. gada 31. decembri (prevalence).
A review on super dense coding over covariant noisy
channels
Authors: Shadman Z. , Kampermann H. , Macchiavello C. , Bruß D.
Published: June 2013

We study the performance of the super dense coding protocol
in the presence of quantum channels with covariant noise.
We first consider the bipartite case and review in a unified
way the case of general Pauli channels. We discuss both the
cases of unitary and non-unitary encoding. We also study
the multipartite scenario and investigate the case of many
senders and one receiver.
Can Education for Sustainable Development Address Challenges in the Arab Region? Examining Business Students’ attitudes and Competences on Education for Sustainable Development: A Case Study
Authors: Kanbar Nancy
Published: June 2013

The population growth together with the unsustainable consumption pattern is putting increasing stress on the planet’s natural resources. The increasing realisation that humans are harming the environment is taking the form of a global movement intended to change behaviour towards sustainability, now recognised as a framework that links humans to nature. Continuous exploitation of natural systems in the Arab region leads to environmental damages that negatively affect human well-being. This article presents a case study from the Reorient University Curricula to Address Sustainability (RUCAS) Tempus project funded by the European Commission. It highlights the results of an empirical study in the Faculty of Business Administration and Economics (FBAE) at Notre Dame University -Louaize (NDU) in Lebanon. The main objective is to assess the need for education for sustainable development (ESD) through an examination of students’ attitudes and competences with the aim of reorienting university curricula to address sustainability. A framework based on the pillars of learning set by UNESCO was developed to measure ESD attitudes and competences. The main findings reveal the need to reorient university courses to address sustainability issues. Attitudes questions suggest that relatively high numbers of students are not aware of their responsibilities for environmental problems, which imply the necessity for a revised curriculum where courses are restructured to inform students of their responsibility for their environment and the quality of life. The results show that the disciplinary competences are significantly lower than the five pillars of learning (general competences) which indicate that the FBAE needs to reorient its curricula to infuse ESD into its programmes through the development of effective pedagogical approaches, teaching methodologies as well as learning materials.
The Students’ Survey of Education for Sustainable Development Competencies: A Comparison Among Faculties
Authors: Biasutti Michele , Surian Alessio
Published: June 2013

The paper reports research employing a quantitative approach to investigating the competences of university students about educating for sustainable development (ESD). Participants were 467 bachelor students of the following five areas: social sciences, educational sciences, applied sciences, engineering and health sciences. The Student Survey of Education for Sustainable Development Competencies was employed. Internal consistency and factor structure of this questionnaire were investigated by assessing Cronbach’s alphas and by performing exploratory factor analysis. Data were subjected to ANOVA for comparing the students of the five faculties. The relevance of factors and the differences between students of different areas were discussed considering also how to infuse ESD principles in university curricula. The aim is reorienting university study programmes in various faculties to prepare students about sustainable development issues.
Branding the Green Education: Challenges Facing Implementation of Education for Sustainable Development in Egypt
Authors: Ramzy Omar , Wahieb Rasha
Published: June 2013

Due to the scarcity in natural resources and the demand for green labour and economy, education for sustainable development (ESD) gained a great importance in developed countries, let alone developing ones. From this point of view, this paper is studying the possibility of infusing ESD in Egypt after one and a half years since January 2011 youth revolution. A primary data gathering method was conducted within a sample of 79 young undergraduate people (67 from the American University in Cairo and 12 fresh graduates from conventional educational systems). The results indicated that there is a positive relationship between high cultural resources along with early childhood awareness and ESD adoption and infusion. Also, Spearman’s rank association test showed a negative relationship between ESD infusion and the satisfaction level of the current conventional curriculum. On the other hand, Spearman’s rank association test showed that α is greater than 0.05; accordingly, there was no correlation between ESD infusion if introduced within the curriculum of an existing well-established university than if introduced as the final outcome of a new university specialised in ESD. The paper highlights the importance of ESD brand associations offered as a service product. After validating the hypothesis, the author discusses the findings and provides solid recommendations for ESD infusion in Egypt.
Education for Sustainable Development: Assessment of the Current Situation at the Faculty of Engineering of Notre Dame University – Louaize
Authors: Salem Talal , Harb Jacques
Published: June 2013

There is a growing need to incorporate educational sustainable development (ESD) principles into engineering education. This paper identifies engineering competencies within the Faculty of Engineering at Notre Dame University - Louaize and the means to shift towards sustainability. ESD tools are used to carry the analysis, keeping in mind the Faculty of Engineering accreditation system ABET, incorporated as the Accreditation Board for Engineering and Technology, Inc., requirements. A survey of the current situation was conducted based on seven key areas: curriculum, research and scholarship, operations, faculty and staff development, outreach and service, student opportunities, administration, mission and planning. The survey revealed some weaknesses that the Faculty of Engineering needs to address for a successful implementation of sustainable practices. ESD is integrated in two selected engineering courses. At the beginning of the course, a questionnaire is used to assess the knowledge, behaviour and attitudes of students. Results show that students currently understand the importance of ESD, but they have a weak knowledge of the relationship between the environment and sustainable future and a bad understanding of sufficient living economy principle. The analysis showed also the need to introduce new courses of sustainability. Nevertheless, the proposed amendment to the curriculum ought to be carried in conjunction with the Faculty of Engineering accreditation system ABET. A wide dissemination of ESD throughout the entire engineering programme will help promoting sustainability. Besides, the infusion of ESD can be implemented within a common engineering course - a mandatory course for all engineering students following ABET amendment procedures.
Reorienting an Educational Psychology Course to Address Sustainability: A Case Study
Authors: Khalil Nehal Lotfy
Published: June 2013

Due to the rapidly changing knowledge, teachers are supposed to teach their students ways of thinking and gathering information, not certain contents that would change shortly. In this sense, sustainability, which, in part, means the preparation of an individual who has the ability to practise critical thinking and to find creative solutions to the problems they face, is considered a must. This paper focuses on the integration of sustainability in curricula, specifically ways of introducing it to students in higher education institutions that provide highly specific and specialised knowledge and skills. So, this study presents a framework for reorienting a university course in the field of physiological psychology to address sustainability. The results of the quantitative analysis showed significant differences at the level of 0.001 between the pre- and post-testing of students’ knowledge of and attitudes towards sustainability in favour of the post-test. While results of qualitative analysis showed positive transformation of students’ practices health wise.
Preliminary Assessment of Balance With the Berg Balance Scale in Adults Who Have a Leg Amputation and Dwell in the Community: Rasch Rating Scale Analysis
Authors: Wong Christopher Kevin , Chen Christine C. , Welsh Jenna
Published: June 2013

Background

Self-report measures of balance and multidimensional mobility assessments are common for people with a leg amputation, yet clinical assessment of balance ability remains less explored. The Berg Balance Scale (BBS), typically used for other populations with impaired balance, has been used for young people with a high level of functioning after traumatic amputation but rarely for older people after vascular amputation.

Objective

The study objective was to examine the psychometric properties of the BBS with Rasch rating scale analysis to determine the validity and utility of the BBS in assessing balance ability in adults who have a leg amputation and dwell in the community.

Design

Rating scale analysis was applied to BBS scores obtained from a single assessment.

Methods

Adult volunteers (men and women) who had a leg amputation (any level and etiology) and dwelled in the community were recruited from a hospital-based community support group and a prosthetic clinic. Rating scale analysis of the BBS was used to assess unidimensionality, internal validity, goodness of fit, structural integrity, and person and item analyses.

Results

The study participants were 40 people (26 men and 14 women; 57.8 [SD=9.7] years old) with leg amputations (24 transtibial, 13 transfemoral, and 3 bilateral) of mixed etiology (32 vascular and 8 nonvascular). The psychometric properties of the BBS confirmed that it measures the unidimensional construct of balance ability with adequate validity and with goodness of fit and structural integrity that meet the acceptability criteria. Person measures revealed that some participants scored near the top of the BBS, suggesting a ceiling effect; item measures revealed that participants with leg amputations had the most difficulty performing the following tasks: standing with 1 leg in front, turning 360 degrees, and placing alternate foot on a stool.

Limitations

Limitations included a convenience sample and a lack of rater reliability testing.

Conclusions

The BBS cohered with the unidimensional construct of balance ability and had strong internal validity for use in a variety of people with leg amputations.
Recent Trends in Intergovernmental Relations
Authors: Marsh Julie A. , Wohlstetter Priscilla
Published: June 2013

In this essay, the authors explore trends in intergovernmental relations (IGR) by analyzing recent education policies—No Child Left Behind Act, Common Core State Standards, and local empowerment policies. Identifying a resurgent role for local actors in education policy, the authors argue that recent federal efforts to exert more control have in many ways strengthened the influence of local actors by providing avenues for school districts and other local “non-system” players to challenge traditional governance arrangements. In a similar vein, because the federal government’s ability to achieve its goals rests primarily on actions of local players, federal policies have in the course of implementation strengthened the hand of many local actors. Based on their analyses, the authors stress that IGR is not a zero-sum game. As one level gains power in certain domains, other levels may simultaneously acquire power in the same or different domains. The authors further argue that relations among federal, state, and local governments are bidirectional. Federal policy often requires states and districts to alter local policies, and conversely, decisions made by states and districts can also influence federal decisions. The authors begin the essay with an overview of the intergovernmental landscape, followed by an analysis of current education policies to illustrate the ways in which local actors have retained and asserted significant control over schooling, despite the expanded federal role in education policy. The essay concludes with questions for future research and practice.
Pure arterial malformation of the posterior cerebral artery: importance of its recognition
Authors: McLaughlin Nancy , Raychev Radoslav , Duckwiler Gary , Martin Neil A.
Published: June 2013

The finding of dilated, elongated, and tortuous vessels on brain imaging should prompt clinicians to determine what vascular anomaly is present. Importantly, not all suspicious serpentine flow voids are manifestations of arteriovenous malformations or arteriovenous fistulas. Other types of intracranial vasculopathies should also be considered. The authors report a rare case of dilated, tortuous, and redundant left posterior communicating artery and left P2 segment of the posterior cerebral artery identified in a young healthy adult that remained stable over a 30-year period. Dynamic and 3D images were critical for determining the type of vascular anomaly and for guiding appropriate management. The authors propose that this case represents a pure arterial malformation and discuss its distinguishing features.
Long-term results of posteromedial hypothalamic deep brain stimulation for patients with resistant aggressiveness
Authors: Torres Cristina V. , Sola Rafael G. , Pastor Jesús , Pedrosa Manuel , Navas Marta , García-Navarrete Eduardo , Ezquiaga Elena , García-Camba Eduardo
Published: June 2013

Object

Erethism describes severe cases of unprovoked aggressive behavior, usually associated with some degree of mental impairment and gross brain damage. The etiology can be epileptic, postencephalitic, or posttraumatic, or the condition can be caused by brain malformations or perinatal insults. Erethism is often refractory to medication, and patients must often be interned in institutions, where they are managed with major restraining measures. The hypothalamus is a crucial group of nuclei that coordinate behavioral and autonomic responses and play a central role in the control of aggressive behavior. Deep brain stimulation (DBS) of the posteromedial hypothalamus (PMH) has been proposed as a treatment for resistant erethism, although experience with this treatment around the world is scarce. The objective of this study was to examine the long-term outcome of PMH DBS in 6 patients with severe erethism treated at the authors' institution.

Methods

Medical records of 6 patients treated with PMH DBS for intractable aggressiveness were reviewed. The therapeutic effect on behavior was assessed by the Inventory for Client and Agency Planning preoperatively and at the last follow-up visit.

Results

Two patients died during the follow-up period due to causes unrelated to the neurosurgical treatment. Five of 6 patients experienced a significant reduction in aggressiveness (the mean Inventory for Client and Agency Planning general aggressiveness score was −47 at baseline and −25 at the last follow-up; mean follow-up 3.5 years). Similar responses were obtained with low- and high-frequency stimulation. In 4 cases, the patients' sleep patterns became more regular, and in 1 case, binge eating and polydipsia ceased. One of the 3 patients who had epilepsy noticed a 30% reduction in seizure frequency. Another patient experienced a marked sympathetic response with high-frequency stimulation during the first stimulation trial, but this subsided when stimulation was set at low frequency. A worsening of a previous headache was noted by 1 patient. There were no other side effects.

Conclusions

In this case series, 5 of 6 patients with pathological aggressiveness had a reduction of their outbursts of violence after PMH DBS, without significant adverse effects. Prospective controlled studies with a larger number of patients are needed to confirm these results.
Predictors of mortality in nontraumatic subdural hematoma
Authors: Busl Katharina M. , Prabhakaran Shyam
Published: June 2013

Object

Subdural hematoma (SDH) is a common diagnosis in neurosurgical and neurocritical practice. Comprehensive outcome data are lacking for nontraumatic SDH. The authors determined which factors are associated with in-hospital mortality in a large sample of patients with nontraumatic SDH.

Methods

Using the Nationwide Inpatient Sample, the authors selected adults who had been hospitalized in the US between 2007 and 2009 and in whom a primary diagnosis of nontraumatic SDH (ICD-9-CM code 432.1) had been made. Demographics, comorbidities, surgical treatment, and discharge outcomes were identified. Univariate and multivariate analyses were performed to identify predictors of in-hospital mortality.

Results

Among 14,093 patients with acute nontraumatic SDH, the mean age was 71.4 ± 14.8 (mean ± standard deviation). In addition, 22.2% of the patients were admitted during the weekend. Surgical evacuation was performed in 51.4% of the patients, and 11.8% of all patients died during hospitalization. In multivariate analyses, patient age (adjusted OR 1.02, 95% CI 1.012–1.022), congestive heart failure (adjusted OR 1.42, 95% CI 1.19–1.71), warfarin use (adjusted OR 1.41, 95% CI 1.17–1.70), coagulopathy (adjusted OR 2.14, 95% CI 1.75–2.61), mechanical ventilation (adjusted OR 16.85, 95% CI 14.29–19.86), and weekend admission (adjusted OR 1.19, 95% CI 1.02–1.38) were independent predictors of in-hospital mortality. Race (Hispanic: adjusted OR 0.65, 95% CI 0.51–0.83; black: adjusted OR 0.78, 95% CI 0.63–0.96), urban hospital location (adjusted OR 0.69, 95% CI 0.54–0.89), and surgical SDH evacuation (adjusted OR 0.52, 95% CI 0.45–0.60) were strong independent predictors for decreased mortality.

Conclusions

One in 9 patients with nontraumatic SDH dies during hospitalization. Among the several predictors of in-hospital mortality, the weekend effect and treatment with surgical evacuation are potentially modifiable factors. Further investigation may lead to improvements in management and outcomes.
Postoperative epidural hematoma covering the galeal flap in pediatric patients with moyamoya disease: clinical manifestation, risk factors, and outcomes
Authors: Choi Hyunho , Lee Ji Yeoun , Phi Ji Hoon , Kim Seung-Ki , Cho Byung-Kyu , Wang Kyu-Chang
Published: June 2013

Object

Postoperative epidural hematoma (EDH), a blood collection between the inserted galeal flap and the overlying skull flap (epigaleal flap hematoma), is a frustrating complication of the surgical treatment of moyamoya disease (MMD) in pediatric patients. The symptoms of postoperative EDH are often similar to those of postoperative cerebral ischemia, and may cause confusion during clinical decision making. The authors designed this study to evaluate the incidence, clinical presentation, risk factors, and treatment outcomes of postoperative EDH in pediatric patients with MMD.

Methods

A retrospective review of 148 pediatric patients with 250 craniotomies who underwent indirect bypass revascularization surgery between January 2002 and December 2006 was performed. This group consisted of 60 male and 88 female patients, and the mean age at surgery was 7.5 years (range 1–18 years).

Results

Of the 250 craniotomies, postoperative EDH was detected in 32 cases. In 12 cases of EDH, surgical treatment was necessary (4.8% of 250 craniotomies). During the same period, 743 non-MMD craniotomy operations were performed. In 6 of these 743 operations, patients developed postoperative EDH that required surgical treatment, significantly less than the percentage of EDH requiring postoperative treatment in patients with MMD (0.8%, p < 0.001). The average interval between craniotomy surgery and the detection of EDH was 1.8 days (range 0–5 days) in patients with MMD and 0.5 days (range 0–2 days; p = 0.018) in the non-MMD craniotomy group.

Postoperative EDH was observed in significantly fewer cases (17 of 191) when a subcutaneous drain (SCD) was inserted over the bone flap than in cases in which an SCD was not inserted (14 of 55; p = 0.001). The mean international normalized ratio of prothrombin time in the immediate postoperative blood test was 1.27 ± 0.17 in the EDH group and 1.20 ± 0.11 in the non-EDH group (values are expressed as the mean ± SD; p = 0.008). Central galeal flap tenting suture and immediate postoperative platelet count were not related to the incidence of postoperative EDH following pediatric MMD surgery.

Conclusions

Postoperative EDH is more likely to be found following craniotomy in patients with MMD than in those without MMD, and may occur in a delayed fashion. Insertion of an SCD and immediate correction of an abnormal value for international normalized ratio of prothrombin time can decrease the incidence of postoperative EDH following surgery for pediatric MMD.
A magnetic resonance imaging, histological, and dose modeling comparison of focused ultrasound, radiofrequency, and Gamma Knife radiosurgery lesions in swine thalamus
Authors: Elias W. Jeff , Khaled Mohamad , Hilliard Justin D. , Aubry Jean-Francois , Frysinger Robert C. , Sheehan Jason P. , Wintermark Max , Lopes Maria Beatriz
Published: June 2013

Object

The purpose of this study was to use MRI and histology to compare stereotactic lesioning modalities in a large brain model of thalamotomy.

Methods

A unilateral thalamotomy was performed in piglets utilizing one of 3 stereotactic lesioning modalities: focused ultrasound (FUS), radiofrequency, and radiosurgery. Standard clinical lesioning parameters were used for each treatment; and clinical, MRI, and histological assessments were made at early (< 72 hours), subacute (1 week), and later (1–3 months) time intervals.

Results

Histological and MRI assessment showed similar development for FUS and radiofrequency lesions. T2-weighted MRI revealed 3 concentric lesional zones at 48 hours with resolution of perilesional edema by 1 week. Acute ischemic infarction with macrophage infiltration was most prominent at 72 hours, with subsequent resolution of the inflammatory reaction and coalescence of the necrotic zone. There was no apparent difference in ischemic penumbra or “sharpness” between FUS or radiofrequency lesions. The radiosurgery lesions presented differently, with latent effects, less circumscribed lesions at 3 months, and apparent histological changes seen in white matter beyond the thalamic target. Additionally, thermal and radiation lesioning gradients were compared with modeling by dose to examine the theoretical penumbra.

Conclusions

In swine thalamus, FUS and radiosurgery lesions evolve similarly as determined by MRI, histological examination, and theoretical modeling. Radiosurgery produces lesions with more delayed effects and seemed to result in changes in the white matter beyond the thalamic target.
Prevalence of patient safety indicators and hospital-acquired conditions in those treated for unruptured cerebral aneurysms: establishing standard performance measures using the Nationwide Inpatient Sample database
Authors: Fargen Kyle M. , Rahman Maryam , Neal Dan , Hoh Brian L.
Published: June 2013

Object

The Agency for Healthcare Research and Quality (AHRQ) patient safety indicators (PSIs) and the Centers for Medicare and Medicaid Services hospital-acquired conditions (HACs) are metrics used to gauge the quality of health care provided by health care institutions. The PSIs and HACs are publicly reported metrics and are directly linked to reimbursement for services. To better understand the prevalence of these adverse events in hospitalized patients treated for unruptured cerebral aneurysms, the authors determined the incidence rates of PSIs and HACs among patients with a diagnosis of unruptured aneurysm in the Nationwide Inpatient Sample (NIS) database.

Methods

The NIS, part of the AHRQ's Healthcare Cost and Utilization Project, was queried for all hospitalizations between 2002 and 2010 involving coiling or clipping of unruptured cerebral aneurysms. The incidence rate for each PSI and HAC was determined by searching the hospital records for ICD-9 codes. The SAS statistical software package was used to calculate incidences and perform multivariate analyses to determine the effects of patient variables on the probability of each indicator developing.

Results

There were 54,589 hospitalizations involving unruptured cerebral aneurysms in the NIS database for the years 2002–2010; 8314 patients (15.2%) underwent surgical clipping and 9916 (18.2%) were treated with endovascular coiling. One thousand four hundred ninety-two PSI and HAC events occurred among the 8314 patients treated with clipping; at least 1 PSI or HAC occurred in 14.6% of these patients. There were 1353 PSI and HAC events among the 9916 patients treated with coiling; at least 1 PSI or HAC occurred in 10.9% of these patients. Age, sex, and comorbidities had statistically significant associations with an adverse event. Compared with the patients having no adverse event, those having at least 1 PSI during their hospitalizations had significantly longer hospital stays (p < 0.0001), higher hospital costs (p < 0.0001), and higher mortality rates (p < 0.0001).

Conclusions

These results estimate baseline national rates of PSIs and HACs in patients with unruptured cerebral aneurysms. These data may be used to gauge individual institutional quality of care and patient safety metrics in comparison with national data.
Changes in pain behavior and glial activation in the spinal dorsal horn after pulsed radiofrequency current administration to the dorsal root ganglion in a rat model of lumbar disc herniation
Authors: Cho Hee Kyung , Cho Yun Woo , Kim Eun Hyuk , Sluijter Menno E. , Hwang Se Jin , Ahn Sang Ho
Published: June 2013

Object

Herniated discs can induce sciatica by mechanical compression and/or chemical irritation caused by proinflammatory cytokines. Using immunohistochemistry methods in the dorsal horn of a rat model of lumbar disc herniation, the authors investigated the effects of pulsed radiofrequency (PRF) current administration to the dorsal root ganglion (DRG) on pain-related behavior and activation of microglia, astrocytes, and mitogen-activated protein kinase.

Methods

A total of 33 Sprague-Dawley rats were randomly assigned to either a sham-operated group (n = 10) or a nucleus pulposus (NP)–exposed group (n = 23). Rats in the NP-exposed group were further subdivided into NP exposed with sham stimulation (NP+sham stimulation, n = 10), NP exposed with PRF (NP+PRF, n = 10), or euthanasia 10 days after NP exposure (n = 3). The DRGs in the NP+PRF rats were exposed to PRF waves (2 Hz) for 120 seconds at 45 V on postoperative Day 10. Rats were tested for mechanical allodynia 10 days after surgery and at 8 hours, 1 day, 3 days, 10 days, 20 days, and 40 days after PRF administration. Immunohistochemical staining of astrocytes (glial fibrillary acidic protein), microglia (OX-42), and phosphorylated extracellular signal–regulated kinases (pERKs) in the spinal dorsal horn was performed at 41 days after PRF administration.

Results

Starting at 8 hours after PRF administration, mechanical withdrawal thresholds dramatically increased; this response persisted for 40 days (p < 0.05). After PRF administration, immunohistochemical expressions of OX-42 and pERK in the spinal dorsal horn were quantitatively reduced (p < 0.05).

Conclusions

Pulsed radiofrequency administration to the DRG reduced mechanical allodynia and downregulated microglia activity and pERK expression in the spinal dorsal horn of a rat model of lumbar disc herniation.
C–C Bond formation catalyzed by natural gelatin and collagen proteins
Authors: Kühbeck Dennis , Bijayi Dhar Basab , Schön Eva-Maria , Cativiela Carlos , Gotor-Fernández Vicente , Díaz Díaz David
Published: June 2013

The activity of gelatin and collagen proteins towards C–C bond formation via Henry (nitroaldol) reaction between aldehydes and nitroalkanes is demonstrated for the first time. Among other variables, protein source, physical state and chemical modification influence product yield and kinetics, affording the nitroaldol products in both aqueous and organic media under mild conditions. Significantly, the scale-up of the process between 4-nitrobenzaldehyde and nitromethane is successfully achieved at 1 g scale and in good yield. A comparative kinetic study with other biocatalysts shows an increase of the first-order rate constant in the order chitosan < gelatin < bovine serum albumin (BSA) < collagen. The results of this study indicate that simple edible gelatin can promote C–C bond forming reactions under physiological conditions, which may have important implications from a metabolic perspective.
Peripheral Compartment as the Initial Access for Hip Arthroscopy in Complex Cases: Technical Note
Authors: Lindeque Bennie G.P. , Gutiérrez Ricardo Cuéllar , Ibán Miguel Ángel Ruiz , Ayestarán Adrián Cuéllar , Sobrino Alberto Sánchez , Oteo-Álvaro Ángel
Published: June 2013

When performing arthroscopic procedures, the hip joint is divided into central and peripheral compartments. Currently, both compartments are evaluated in most of the procedures, but the procedures are usually started by accessing the central compartment. When a direct approach to the central compartment is significantly impeded, it is necessary to perform the initial arthroscopic approach to the hip from the peripheral compartment using either an intracapsular technique or an extracapsular technique. The technical pearls that might be required in these patients are discussed, and typical clinical cases are presented.
Platelet-rich Plasma Promotes Healing of Osteoporotic Fractures
Authors: Chen Linwei , Yang Xiaobo , Huang Gao , Song Dianwen , Ye Xue-Shi , Xu Huazi , Li Wanli
Published: June 2013

With an aging population worldwide, the frequency of osteoporotic fractures is increasing. Therefore, biological methods to enhance the internal fixation of osteoporotic fractures becomes more important to reduce the societal burden of care. The purposes of this study were to evaluate the role of platelet-rich plasma (PRP) in the treatment of osteoporotic fractures and to clarify the best concentration of PRP. Bone marrow mesenchymal stem cells isolated from osteoporotic rats were cultured in high- (8.21±0.4×10
9
/mL), medium-(2.65±0.2×10
9
/mL), and low-concentration (0.85±0.16×10
9
/mL) PRP and in platelet-poor plasma (8±0.5×10
6
platelet/mL). The capacities of cell proliferation and osteogenic and adipogenic differentiation were compared. A transverse osteotomy was performed in the middle of the left femoral diaphysis followed by K-wire fixation, and various concentrations of PRP were transplanted into the fracture zone. Radiologic, mechanical, and histologic evaluations were performed at 2, 4, and 8 weeks, respectively. The results indicated that PRP could inhibit adipogenic differentiation and that medium-concentration PRP was effective in inducing the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells derived from osteoporotic bone marrow and in promoting fracture healing, whereas high-concentration PRP inhibited osteogenic differentiation and callus remodeling. Certain concentrations of PRP can effectively enhance the healing of osteoporotic fractures. Medium-concentration PRP is a suitable concentration to use in practice.
Febrile Response Following Megaprosthesis Replacement for Primary Bone Sarcoma
Authors: Kim Wanlim , Han Ilkyu , Lee Sang A. , Cho Hwan Seong , Kim Han Soo
Published: June 2013

The presence of early postoperative fever after megaprosthesis replacement surgery is a concern for orthopedic oncologists due to the possibility of infection. The aims of the current study were to determine the incidences and patterns of fever and factors associated with its development and to determine the clinical significance of fever after megaprosthesis replacement surgery.

Seventy-one patients who had undergone megaprosthesis reconstruction for previously unoperated localized lower-extremity osteosarcoma were reviewed. No patient had evidence of infection preoperatively. Mean patient age was 23.72±16.84 years (range, 6.7–74 years), and average follow-up was 59.5 months (range, 4–240 months). Five postoperative surgical wound infections (4 deep, 1 superficial) occurred on postoperative days 5, 13, 14, 20, and 21. Fevers (body temperature of 38°C or higher) were present in 62 patients (87.3%) at some point during the first 2 postoperative weeks. Peak body temperature was observed on postoperative day 1 in 62% of the febrile patients. Of the 62 febrile patients, 94% were relieved of fever by postoperative day 5. No significant association was observed between the presence of fever and surgical wound infection. Body temperature curves in patients with infection showed that several atypical patterns, such as multiple fever peaks and persistent fever, were accompanied by physical findings within the normalization period.

Fever during the first 5 postoperative days is common after megaprosthesis replacement for bone sarcomas and seems to be a normal physiologic response to surgery. However, atypical fever patterns or additional physical findings require investigation.
Predictive Factors of Recovery in Long Thoracic Mononeuropathy
Authors: Mondelli Mauro , Aretini Alessandro , Ginanneschi Federica
Published: June 2013

The aim of the study was to identify specific factors that affect the outcome in patients with long thoracic mononeuropathy. The authors reviewed all medical records of patients with long thoracic mononeuropathy from the archive of the electromyography service over the past 16 years. Age, sex, occupation, pain at onset, symptom duration, neuropathy causes and side, and electromyography findings were collected. The outcome was evaluated by performing standard telephone interviews consisting of 9 queries about use limitations in the affected upper limb. If no limitation existed, the recovery was considered complete. If partial limitations only affected the upper limb in performing 5 or fewer of 9 specific activities, the outcome was considered good; if limitations affected more than 5 activities, the outcome was considered poor. The authors performed a multivariate logistic regression to calculate the association between good outcome or full recovery and poor outcome with demographic, clinical, and electromyography findings. Forty-one patients were included (mean±SD age, 39±14 years; 68.3% men). Causes were shoulder-arm overuse or trauma in 19 patients, iatrogenic in 5, idiopathic in 9, and inflammatory in 8. Twenty-seven patients had a good outcome and full recovery and 14 had a poor outcome. No patient underwent surgery. Age, sex, occupation, pain at onset, symptom duration, neuropathy side, and electromyography findings were not predictive of the outcome. The probability of full recovery and good outcome was 7.5 times greater in long thoracic mononeuropathy secondary to idiopathic or inflammatory causes compared with other etiologies.