bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress analysis in a pedicle screw fixation system with flexible rods in the lumbar spine
Authors: Kim Kyungsoo , Park Won Man , Kim Yoon Hyuk , Lee SuKyoung
Published: October 2009

Breakage of screws has been one of the most common complications in spinal fixation systems. However, no studies have examined the breakage risk of pedicle screw fixation systems that use flexible rods, even though flexible rods are currently being used for dynamic stabilization. In this study, the risk of breakage of screws for the rods with various flexibilities in pedicle screw fixation systems is investigated by calculating the von Mises stress as a breakage risk factor using finite element analysis. Three-dimensional finite element models of the lumbar spine with posterior one-level spinal fixations at L4—L5 using four types of rod (a straight rod, a 4 mm spring rod, a 3 mm spring rod, and a 2 mm spring rod) were developed. The von Mises stresses in both the pedicle screws and the rods were analysed under flexion, extension, lateral bending, and torsion moments of 10 N m with a follower load of 400 N. The maximum von Mises stress, which was concentrated on the neck region of the pedicle screw, decreased as the flexibility of the rod increased. However, the ratio of the maximum stress in the rod to the yield stress increased substantially when a highly flexible rod was used. Thus, the level of rod flexibility should be considered carefully when using flexible rods for dynamic stabilization because the intersegmental motion facilitated by the flexible rod results in rod breakage.
Performance of the resurfaced hip. Part 1: The influence of the prosthesis size and positioning on the remodelling and fracture of the femoral neck
Authors: Dickinson A S , Taylor A C , Browne M
Published: October 2009

Hip resurfacing is an established treatment for osteoarthritis in young active patients. Failure modes include femoral neck fracture and prosthesis loosening, which may be associated with medium-term bone adaptation, including femoral neck narrowing and densification around the prosthesis stem. Finite element modelling was used to indicate the effects of prosthesis sizing and positioning on the bone remodelling and fracture strength under a range of normal and traumatic loads, with the aim of understanding these failure modes better. The simulations predicted increased superior femoral neck stress shielding in young patients with small prostheses, which required shortening of the femoral neck to give an acceptable implant—bone interface. However, with a larger prosthesis, natural femoral head centre recreation in the implanted state was possible; therefore stress shielding was restricted to the prosthesis interior, and its extent was less sensitive to prosthesis orientation. With valgus orientation, the implanted neck strength was, at worst, within 3 per cent of its intact strength. The study suggests that femoral neck narrowing may be linked to a reduction in the horizontal femoral offset, occurring if the prosthesis is excessively undersized. As such, hip resurfacing should aim to reproduce the natural femoral head centre, and, for valgus prosthesis orientation, to avoid femoral neck fracture.
Emergency peripartum hysterectomy in a tertiary hospital in Lagos, Nigeria: a five-year review
Authors: Rabiu K A , Akinlusi F M , Adewunmi A A , Akinola O I
Published: October 2009

This was a retrospective descriptive study of all the patients who underwent emergency peripartum hysterectomy from January 1st 2003 to December 31st 2007 at the Lagos State University Teaching Hospital. Of the 15,067 deliveries during the study period, 57 patients had emergency peripartum hysterectomy (3.78/1000 deliveries). 19.3% of these patients were booked for antenatal care in the hospital, while 80.7% were unbooked. The mean age of patients was 32.7 years (SD = 5.5) and the mean parity was 3.08 (SD = 1.9). The major indications for emergency peripartum hysterectomy were ruptured uterus (77.2%), uterine atony (10.5%), abruptio placentae (3.5%) and sepsis (3.5%). Subtotal hysterectomy was performed in 96.5% of the cases. The maternal mortality was 19.3% and the perinatal mortality was 75.4%. The incidence of emergency peripartum hysterectomy in this study is high and the major indication is ruptured uterus. It is associated with high maternal and perinatal morbidity and mortality.
Amoebic liver abscess: experience in a south Asian country
Authors: Rehman Alvi A , Rizvi Farrukh , Kazim Syed Faraz , Ejaz Kiran , Zafar Hasnain , Chawla Tabish , Bibi Shahida , Rehman Zia Ur
Published: October 2009

Amoebic liver abscess (ALA) is endemic in south Asian countries. The current study was undertaken in order to evaluate the clinical spectrum, management and outcome of ALA at an urban tertiary care hospital in Pakistan. The chart notes of 232 ALA patients admitted from 1 January 2000 to 31 August 2007 were retrospectively reviewed. The most frequent clinical findings included: fever (96.5%); right upper abdomen pain (80.2%); liver tenderness (73.5%); tachycardia (61.6%); hepatomegaly (60%); nausea and vomiting (42%); and jaundice (23.9%). The duration of symptoms was less than 14 days in 70% . Ultrasound examinations revealed 69% of the abscesses were in the right lobe, 19% in the left lobe and 12% in both lobes. The size of the abscess was greater than 5.0 cm in 83%. Seventy-seven percent of the patients had a single abscess and 23% had multiple abscesses. Ultrasound-guided therapeutic aspiration was performed in 64%, but 36% were treated with antibiotics alone. Metronodazole was the most frequently used antibiotic. However, various combinations of antibiotics were also used without any obvious justification.
The clinical profile and predictors of mortality in patients with melioidosis in South India
Authors: Chrispal Anugrah , Rajan Sudha Jasmine , Sathyendra Sowmya
Published: October 2009

Melioidosis is an underdiagnosed and underreported disease in India with protean clinical manifestations. Mortality in this study population was 17%. The predominant risk factor for melioidosis was diabetes mellitus. Multifocal disease was present in 66% and pulmonary involvement in 61% of patients. In a country like India where the conditions are conducive for endemic melioidosis and due to the clinical similarity of melioidosis to diseases like tuberculosis, it is essential for clinicians to have a high degree of suspicion and pursue suitable diagnostic strategies for melioidosis in the appropriate clinical setting.
Abdominal wall hernia repair in cirrhotic patients: outcomes seen at a tertiary care hospital in a developing country
Authors: Khan Muhammad Rizwan , Kassi Mahwash , Janjua Sahar Ashraf
Published: October 2009

The outcome of hernia repair in patients with cirrhosis remains poor when compared to non-cirrhotics. The aim of our study was to evaluate the outcome of hernia repair in cirrhotic patients at our tertiary care hospital located in a developing country. A total of 61 patients with cirrhosis underwent hernia repair from January 2001 to December 2007 at our hospital. The mean age of the patients was 52 years and there were 30 males. Early postoperative complications were noted in 20 (33%) patients including two mortalities. The incidence of early complications was higher (71%) in patients with Child class C cirrhosis as compared to patients with either Child class A or B cirrhosis (21%), and the difference was statistically significant ( P < 0.001). Except in emergency circumstances, surgery in Child class C patients may either be delayed until the patient is medically optimized or performed early before liver disease progresses to severe decompensation.
Diagnostic utility of a single Widal test in the diagnosis of typhoid fever at Aga Khan University Hospital (AKUH), Nairobi, Kenya
Authors: Omuse Geoffrey , Kohli Ruchika , Revathi Gunturu
Published: October 2009

Typhoid fever is a systemic illness caused by Salmonella enterica serovar typhi ( S. typhi) and is endemic in Kenya, where a single Widal test done on an acute phase serum is the most commonly used test. Using a cut-off value of 1:320 for both O and H agglutinins as being diagnostic of S. typhi, only 18 (26%) of our patients had diagnostic titres; 37 (53.6%) had O and H titres less than 1:40. Our study showed that Widal testing done on an acute phase serum of a patient suspected to have typhoid fever had limited diagnostic capability given its low sensitivity.
Optical urethrotomy under local anaesthesia is a feasible option in urethral stricture disease
Authors: Munks D G , Alli M O , Goad E H Abdel
Published: October 2009

The aim of our study was to assess the feasibility of performing optical urethrotomy for urethral stricture disease under local anaesthesia. A total of 33 patients with radiologically proven urethral stricture underwent optical urethrotomy by a single operator under local anaesthesia. Of these patients, 23 (70%) had stricture involving the corpora spongiosum and 18 (55%) of the patients were dependent on supra-pubic catheters. The procedure was successful in 30 cases (91%). The procedure was very well tolerated (average visual analogue pain score of 2/10) with an extremely low complication rate. The large number of patients with urethral stricture disease and the premium on operating time on formal theatre slates encouraged us to perform these procedures under local anaesthetic. Although most patients had severe stricture disease, the majority of cases were successful and very well tolerated. Optical urethrotomy under local anesthesia could be a viable option in the absence of formal theatre time and the facilities to perform general anaesthesia.
Challenge Point Framework and Efficient Learning of Golf
Authors: Guadagnoli Mark , Lindquist Kristina
Published: October 2009

The current paper overviews a framework for motor learning and uses this framework to suggest efficient means to practice golf. The framework, known as the Challenge Point Framework, was built from years of laboratory and field studies that have been shown to enhance learning. Throughout the paper, the relationship between practice protocols and the learning that results from them are discussed and where appropriate golf-related examples are provided for the reader to be able to translate from motor learning and neuroscience research to the application of golf. Ultimately the aim of the article is to show how the Challenge Point Framework can be used to enhance golf performance
Nonsense-mediated mRNA decay mutes the splicing defects of spliceosome component mutations
Authors: Kawashima Tadashi , Pellegrini Matteo , Chanfreau Guillaume F.
Published: October 2009

The role of many splicing factors in pre-mRNA splicing and the involvement of these factors in the processing of specific transcripts have often been defined through the analysis of loss-of-function mutants in vivo. Here we show that inactivating the nonsense-mediated mRNA decay (NMD) results in an enhancement of splicing phenotypes associated with several S. cerevisiae splicing factor mutations. Tiling microarrays showed that inactivation of the NMD factor Upf1p in the prp17Δ and prp18Δ mutant strains results in a larger spectrum of splicing defects than what is observed in the single mutants, including new transcripts previously shown unaffected by Prp17p or Prp18p inactivation. Inactivation of Upf1p in the second step/recycling factor prp22-1 mutant and in the nam8Δ and mud1Δ U1 snRNP component mutants also increase unspliced precursor accumulation of several specific transcripts. In addition, deletion of UPF1 partially suppresses the growth defects associated with the prp17Δ or prp22-1 mutations, demonstrating a positive genetic interaction between NMD and splicing factor mutants. These results show that RNA surveillance by NMD can mask some of the effects of splicing factor mutations, and that the roles of splicing factors cannot be fully understood in vivo unless RNA degradation systems that degrade unspliced precursors are also inactivated.
CpG-island promoters drive transcription of human telomeres
Authors: Nergadze Solomon G. , Farnung Benjamin O. , Wischnewski Harry , Khoriauli Lela , Vitelli Valerio , Chawla Raghav , Giulotto Elena , Azzalin Claus M.
Published: October 2009

The longstanding dogma that telomeres, the heterochromatic extremities of linear eukaryotic chromosomes, are transcriptionally silent was overturned by the discovery that DNA-dependent RNA polymerase II (RNAPII) transcribes telomeric DNA into telomeric repeat-containing RNA (TERRA). Here, we show that CpG dinucleotide-rich DNA islands, shared among multiple human chromosome ends, promote transcription of TERRA molecules. TERRA promoters sustain cellular expression of reporter genes, are located immediately upstream of TERRA transcription start sites, and are bound by active RNAPII in vivo. Finally, the identified promoter CpG dinucleotides are methylated in vivo, and cytosine methylation negatively regulates TERRA abundance. The existence of subtelomeric promoters, driving TERRA transcription from independent chromosome ends, supports the idea that TERRA exerts fundamental functions in the context of telomere biology.
Sliced microRNA targets and precise loop-first processing of MIR319 hairpins revealed by analysis of the Physcomitrella patens degradome
Authors: Addo-Quaye Charles , Snyder Jo Ann , Park Yong Bum , Li Yong-Fang , Sunkar Ramanjulu , Axtell Michael J.
Published: October 2009

Expression profiling of the 5′ ends of uncapped mRNAs (“degradome” sequencing) can be used to empirically catalog microRNA (miRNA) targets, to probe patterns of miRNA hairpin processing, to examine mRNA decay, and to analyze accumulation of endogenous short interfering RNA (siRNA) precursors. We sequenced and analyzed the degradome of the moss Physcomitrella patens, an important model system for functional genomic analyses in plant evolution. A total of 52 target mRNAs of 27 different Physcomitrella miRNA families were identified. Many targets of both more conserved and less conserved miRNA families encoded putative regulatory proteins. Remnants of MIRNA hairpin processing also populated the degradome data and indicated an unusual “loop-first” mode of precise processing for the MIR319 gene family. Precise loop-first processing was confirmed for native Physcomitrella, rice, and Arabidopsis MIR319 hairpins, as well as an Arabidopsis artificial MIRNA (aMIRNA) based upon a MIR319 backbone. MIR319 is thus a conserved exception to the general rule of loop-last processing of MIRNA hairpins. Loop-first MIR319 processing may contribute to the high efficacy of a widely used MIR319-based strategy for aMIRNA production in plants.
Powering through ribosome assembly
Authors: Strunk Bethany S. , Karbstein Katrin
Published: October 2009

Ribosome assembly is required for cell growth in all organisms. Classic in vitro work in bacteria has led to a detailed understanding of the biophysical, thermodynamic, and structural basis for the ordered and correct assembly of ribosomal proteins on ribosomal RNA. Furthermore, it has enabled reconstitution of active subunits from ribosomal RNA and proteins in vitro. Nevertheless, recent work has shown that eukaryotic ribosome assembly requires a large macromolecular machinery in vivo. Many of these assembly factors such as ATPases, GTPases, and kinases hydrolyze nucleotide triphosphates. Because these enzymes are likely regulatory proteins, much work to date has focused on understanding their role in the assembly process. Here, we review these factors, as well as other sources of energy, and their roles in the ribosome assembly process. In addition, we propose roles of energy-releasing enzymes in the assembly process, to explain why energy is used for a process that occurs largely spontaneously in bacteria. Finally, we use literature data to suggest testable models for how these enzymes could be used as targets for regulation of ribosome assembly.
Use of Isothermal Conduction Calorimetric Method for Measuring the Heat of Hydration of Cement
Authors: Wang Hugh , Qi Chengqing , Lopez Waltter , Farzam Hamid
Published: October 2009

In the present study, an extensive test program is conducted to measure and compare the heat of hydration obtained from both calorimeter and ASTM C186-05 test methods. A statistical analysis is performed to evaluate the variations of the test data. The results indicate that the isothermal conduction calorimeter method is a more reliable, less time-consuming, and less labor-intensive method than the ASTM C186-05 test method. The heat of hydration at 3 days showed the least variation in all calorimeter tests. These suggest that ASTM shall consider adopting the isothermal conduction calorimeter method for measuring the heat of hydration of cement. The 3-day heat of hydration value can be used for specifying the limit of heat release for type II cements.
More Accurate Approximation of J-Integral Equation for Evaluating Fracture Resistance Curves
Authors: Zhu Xian-Kui , Joyce James A.
Published: October 2009

Accurate estimate of the J integral is required in a valid experimental evaluation of J-based fracture resistance curves for ductile materials. The fracture toughness test standard ASTM E1820 allows a basic method and a resistance curve method to be used experimentally to evaluate the J values via standard specimens. The basic method obtains J estimates using the η factor method that was developed for a stationary crack. The resistance curve method obtains crack growth corrected J estimates using an incremental equation that was proposed by Ernst et al. (“Estimation on J-Integral and Tearing Modulus T from a Single Specimen Test Record,” Fracture Mechanics: Thirteenth Conference, ASTM STP 743, 1981, pp. 476–502) for a growing crack and has been accepted as the most accurate equation available for about three decades. Recently, Neimitz (“The Jump-Like Crack Growth Model, the Estimation of Fracture Energy and JR Curve,” Eng. Fract. Mech., Vol. 75, 2008, pp. 236–252), and Kroon et al. (“A Probabilistic Model for Cleavage Fracture with a Length Scale-Parameter Estimation and Predictions of Growing Crack Experiments,” Eng. Fract. Mech., Vol. 75, 2008, pp. 2398–2417) presented two different approximate equations for the J-integral, which they proposed as more accurate than the Ernst equation. Therefore, further investigation is needed to determine a truly accurate approximation for the J-integral equation. With this objective, the present paper proposes different mathematical and physical models to approximate the J-integral equation. The physical models are developed in terms of the deformation theory and the jump-like crack growth assumption. Relations between the proposed models and the existing equations are identified. Systematic evaluations of the proposed models are then made using a theoretical procedure of J-R curves for both low and high strain hardening materials, and using experimental data from an actual single edge-notched bend specimen made of HY80 steel. Accuracy of the proposed models is determined, and a more accurate approximation of J-integral equation is thus suggested for J-R curve testing.
Application of Artificial Neural Network for Fatigue Life Prediction under Interspersed Mode-I Spike Overload
Authors: Mohanty J. R. , Verma B. B. , Ray P. K. , Parhi D. R. K
Published: October 2009

The objective of this study is to design multi-layer perceptron artificial neural network (ANN) architecture in order to predict the fatigue life along with different retardation parameters under constant amplitude loading interspersed with mode-I overload. Fatigue crack growth tests were conducted on two aluminum alloys 7020-T7 and 2024-T3 at various overload ratios using single edge notch tension specimens. The experimental data sets were used to train the proposed ANN model to predict the output for new input data sets (not included in the training sets). The model results were compared with experimental data and also with Wheeler’s model. It was observed that the model slightly over-predicts the fatigue life with maximum error of + 4.0 % under the tested loading conditions
Analysis of the driving characteristics for an ACPDP with an auxiliary electrode using the voltage‐transfer closed surface
Authors: Lee Seong Min , Jang Cheol , Cho Kwan Hyun , Choi Kyung Cheol
Published: October 2009

Abstract— The driving characteristics and wall‐charge model of an ac plasma‐display panel (ACPDP) with an auxiliary electrode were investigated by using voltage‐transfer closed‐surface modeling. To understand the wall‐charge behavior of an ACPDP with an auxiliary electrode qualitatively, voltage‐transfer closed‐surface analysis was applied to a test panel under the full driving waveform. The voltage‐transfer closed surfaces were obtained after the sustain, reset, and address periods, when the full‐stage driving waveform was employed with the test panel. As a result, it was proven that the wall‐charge model predicted in the previous work corresponded with the wall‐charge behavior of an ACPDP with an auxiliary electrode. Also, based on the resultant form after the address period, the wall‐charge model after the address period was recently added and the entire wall‐charge model was completed in this work. In addition, by investigating the trajectory of the cell‐state movement during the reset period, it was confirmed that the priming effect affected the reduced discharge time lag of an ACPDP with an auxiliary electrode under the newly proposed driving waveform for reducing address time lag.
Methods to reduce power dissipation and supply voltage of LCD drivers
Authors: Thirunarayanan Raghavasimhan , Ruckmongathan Temkar N.
Published: October 2009

Abstract— Methods to reduce the power dissipation and supply voltage of LCD drivers for several line‐by‐line addressing techniques (viz., addressing based on Hadamard matrices, diagonal matrices, and wavelets) are proposed, based on the analysis and estimation of power dissipation in the drivers. Power dissipation, supply voltage, number of time intervals required to address the display, and maximum number of voltage levels in the addressing waveforms of these techniques are compared with that of the Successive Approximation Technique.
Memory‐color segmentation and classification using class‐specific eigenregions
Authors: Fredembach Clément , Estrada Francisco , Süsstrunk Sabine
Published: October 2009

Abstract—Memory colors refer to the color of specific image regions that have the essential attribute of being perceived in a consistent manner by human observers. In color correction — or rendering — tasks, this consistency implies that they have to be faithfully reproduced; their importance, in that respect, is greater than that for other regions in an image. There are various schemes and attributes to detect memory colors, but the preferred method remains to segment the images into meaningful regions, a task for which many algorithms exist. Memory‐color regions are not, however, similar in their attributes. Significant variations in shape, size, and texture exist. As such, it is unclear whether a single segmentation algorithm is the most adapted for all of these classes. By using a large database of real‐world images, class‐specific geometrical features, eigenregions, were calculated. They can be used to evaluate how well an algorithm is adapted to segment a given class. A measure of localization of memory colors is given. The performance of class‐specific eigenregions were compared to general ones in the task of memory‐color‐region classification and it was observed that they provide a noticeable improvement in classification rates.
Mechanical integrity of touch‐screen components
Authors: Sierros Konstantinos A. , Kukureka Stephen N.
Published: October 2009

Abstract— Despite efforts to replace them, ceramic‐coated polymer electrodes are still enjoying an extensive use in touch‐screen applications. Their mechanical behavior is of importance and can have an effect on the structural integrity of the touch system. In this paper, the mechanical and tribological response of such electrodes, under cyclic loading conditions, is investigated. Controlled buckling experiments and reciprocating wear studies are performed. Buckling experimental results suggest that the residual stresses present in the film can play an important role in the overall mechanical integrity of the device. Also, tribological studies show that an irreversible damage of the ITO functionality, above 1000 reciprocating cycles, takes place. Understanding and improving the mechanical and tribological reliability of touch‐screen electrodes will result in designing touch‐screen devices with enhanced structural integrity.
Strategy Implementation by State Transportation Agencies to Maintain Work Zone Mobility and Safety
Authors: Wiegand Jonathan D. , Maze T. H.
Published: October 2009

Mitigation strategies for work zone congestion are used by transportation agencies to manage or reduce congestion through a work zone as part of the project's transportation management plan. The objective of this research is to assist agencies’ strategy selection by identifying strategies used by state transportation agencies (STAs) nationwide and their experiences. An online survey was developed to identify current, past, and future strategy implementation for projects similar to four developed scenarios: rural reconstruction, rural resurfacing, urban reconstruction, and urban resurfacing projects. The survey received 42 responses from individuals representing 28 states (responses were received from multiple districts or regions from a few states). It was found that agencies used several strategies to address different aspects of mobility and safety. Strategy selection varied between facility location and work activity. STAs also provided strategies that failed to meet expectations and identified strategies their agency plans to implement in the future. Based on the survey results and gaps in current literature, recommendations for strategy selection and future research are provided.
QuickZone Improvement for Rural Freeway and Model Validation
Authors: Gou Jizhan , Zhang Li , Altman Jeffrey C. , Davis Will
Published: October 2009

This review indicated that in QuickZone 2.0 a deterministic queuing model is applied to calculate the delays for oversaturated conditions; stochastic and speed reduction delays were not included. Data collected from rural freeways in Mississippi show that saturated and oversaturated traffic flow may not occur in work zones. For situations like this, the delay components that are not included in QuickZone are significant. The current delay model of QuickZone needs improvement. This paper describes a model improvement made to QuickZone. The improvement considers delays from the deceleration before a work zone, slow-moving traffic along the work zone, acceleration after the work zone, and stochastic delays within the work zone area. The Excel Visual Basic Application implementation of the model in QuickZone is discussed in this paper. Traffic flow parameters such as speed and volume of more than 10 work zones in the rural area of Mississippi were collected to verify the newly improved QuickZone in undersaturated conditions; CORSIM, traffic simulation software sponsored by FHWA, was utilized to compare the delay from the improved QuickZone for the work zones in oversaturated conditions. Verification results from the numerical examples showed that the improved QuickZone provided more reasonable delay estimations than the original version did, especially for rural work zones in under-saturated conditions. Therefore, the improved QuickZone can capture the delays in undersaturated and oversaturated conditions.
Benefits of Pavement Markings
Authors: Carlson Paul J. , Park Eun Sug , Andersen Carl K.
Published: October 2009

One of the most important aspects of a safe and efficient roadway is the uniform application of pavement markings to delineate the roadway path and specific traffic travel lanes. Pavement markings can communicate information to road users as no other traffic control device can. They provide continuous information to road users related to roadway alignment, vehicle positioning, and other important driving-related tasks. It is estimated that in the United States alone, approximately $2 billion is spent annually on pavement markings. Despite these expenditures, there is a general void in terms of a consolidated effort to quantify proven benefits of pavement markings, although many research projects have focused on specific elements of pavement markings. This paper was developed to bring together many of the recent and ongoing research efforts to demonstrate a renewed perspective regarding the benefits of pavement markings and, where information is available, describe the benefits of various aspects of pavement markings. This paper presents areas where conclusive findings are available, and describes areas where findings are available but show inconsistent and sometimes conflicting results.
Benefit–Cost Analysis of Maintenance Decision Support System
Authors: Ye Zhirui , Strong Christopher K. , Shi Xianming , Conger Steven M. , Huft David L.
Published: October 2009

The pooled fund study of the Maintenance Decision Support System (MDSS), led by South Dakota and now including 13 state departments of transportation, developed an operational MDSS for winter maintenance. While the MDSS is generally perceived to be beneficial, it is important to determine more formally the tangible benefits and costs associated with its implementation and to determine whether it is a good investment. This paper presents the results of a benefit–cost analysis of the pooled fund MDSS. The development of the analysis method includes the identification of benefits and costs, the definition of base case and alternatives, and the development of a benefit–cost model. A base case (without MDSS) and two other alternatives (with MDSS) are defined for the analysis. The developed method consists of two parallel modules: a baseline data module and a simulation module. Results from a case study applying this method show that the implementation of MDSS brings more benefits than costs.
Evaluation of Effects of Weather Information on Winter Maintenance Costs
Authors: Ye Zhirui , Shi Xianming , Strong Christopher K. , Greenfield Tina H.
Published: October 2009

The objective of this study is to investigate and evaluate the effects of weather information (in terms of accuracy and frequency of usage) on winter maintenance costs. To this end, a general winter maintenance cost model is presented, and then a methodology combining sensitivity analysis and neural network methods is proposed. Sensitivity analysis is used to identify the key input variables that significantly affect the output variable. The proposed method and cost model are applied to a case study of the Iowa winter maintenance operations. The results from the case study show that the lane miles of roadway maintained by maintenance units have the most important impact on winter maintenance costs; also, the increased use and accuracy of weather information can reduce costs. Finally, a benefit–cost analysis shows that the use of accurate weather information is a promising way to reduce winter maintenance costs.
Computer-Aided Design of Passive Snow Control Measures
Authors: Chen Stuart S. , Lamanna Michael F. , Tabler Ronald D. , Kaminski Darrell F.
Published: October 2009

Control of blowing and drifting snow on the nation's highways is important to reducing maintenance costs and closure times and to improving crash incidence by improving visibility, preventing drifting on the road, and reducing road icing. Means of engineered mitigation using road design and snow fences have been incorporated into a software tool, SnowMan (for Snow Management), that has been deployed for use statewide within the New York State Department of Transportation. The software has been developed as a MicroStation Development Language application to run within the Bentley Micro-Station CAD software environment used in highway design projects. The scope of SnowMan includes drift prediction (mitigated and unmitigated), evaluation of roadway cross sections and determination of trial fence solutions subject to combinations of height, setback, porosity constraints, and prescription of upwind earthwork solutions. This paper describes the development and implementation of this software tool for mitigation of blowing and drifting snow problems and illustrates its usage, while also providing an overview of the relevant data, underlying algorithms, and engineering approaches to blowing and drifting snow mitigation as implemented in SnowMan.
Endovascular coil occlusion of 152 middle cerebral artery aneurysms: initial and midterm angiographic and clinical results
Authors: Bracard Serge , Abdel-Kerim Amr , Thuillier Lorrena , Klein Olivier , Anxionnat René , Finitsis Stefanos , Lebedinsky Ariel , de Freitas Clayton Maceido , Pinheiro Nilson , de Andrade Guillerme Cabral , Picard Luc
Published: October 2009

Object

The object of this study was to evaluate the initial and mid-term angiographic and clinical results after endovascular coil occlusion of middle cerebral artery (MCA) aneurysms at the authors' institution.

Methods

The authors conducted a retrospective analysis of a consecutive series of 152 MCA aneurysms (73 ruptured) treated by endovascular coiling in 140 patients. Angiographic and clinical data at initial and midterm follow-up as well as procedure-related complications were prospectively registered.

Results

At discharge, favorable clinical outcomes (Glasgow Outcome Scale score of 1 or 2) were obtained in 89.3% of patients (125/140). Seven patients (5%) were in a vegetative state or had died. Complications were encountered in association with 11.8% of the procedures (18/152), and most (13/18) involved thromboembolic events (which led to permanent ischemia in 4 cases and death in 1). The overall procedure-related mortality rate was 0.7%, and the rates of permanent and transient morbidity were 2.6 and 2%, respectively. At a mean follow-up duration of 4.3 years there had been 4 cases of rebleeding: early rebleeding occurred during the initial postoperative period in 3 cases and later in 1. Total or subtotal occlusion was obtained in 84.2% of aneurysms (128/152). At follow-up, this satisfactory occlusion persisted in 83.3% of aneurysms (110/132) at 1 year posttreatment, 79.5% (89/112) at 3 years, and 80.2% (73/91) at 5 years.

Conclusions

Risks and initial and midterm angiographic and clinical results after endovascular treatment of MCA aneurysms are nearly identical to other locations. Endovascular treatment may thus be proposed as an alternative to surgical clipping at this location. Nevertheless, a longer follow-up period is necessary to determine its efficacy, particularly in cases of unruptured aneurysms.
Microvascular decompression of the optic chiasm
Authors: McLaughlin Nancy , Bojanowski Michel W.
Published: October 2009

Elongation of the anterior cerebral artery (ACA) and subsequent compression of the chiasm rarely have been reported as causes of a visual field deficit. Neither has microvascular decompression of the chiasm been described in this circumstance. The authors report on a case of progressive visual deficits caused by compression of the optic apparatus by a right elongated ACA as documented on MR imaging. Microvascular decompression was proposed as treatment. The right A1 segment was larger than usual and tortuous, transmitting its pulsations into the chiasm. A piece of Teflon was inserted between the A1 segment and the chiasm. Following surgery, the visual field deficit progressively improved. At 4 months after surgery, the patient's visual fields were normal. Therefore, an elongated ACA can compress the chiasm and result in a visual field deficit. In such circumstances when facing a progressive visual field deficit, microvascular decompression may improve vision.
Gamma Knife radiosurgery for trigeminal neuralgia: the impact of magnetic resonance imaging–detected vascular impingement of the affected nerve
Authors: Sheehan Jason P. , Ray Dibyendu Kumar , Monteith Stephen , Yen Chun Po , Lesnick James , Kersh Ronald , Schlesinger David
Published: October 2009

Object

Trigeminal neuralgia is believed to be related to vascular compression of the affected nerve. Radiosurgery has been shown to be reasonably effective for treatment of medically refractory trigeminal neuralgia. This study explores the rate of occurrence of MR imaging–demonstrated vascular impingement of the affected nerve and the extent to which vascular impingement affects pain relief in a population of trigeminal neuralgia patients undergoing Gamma Knife radiosurgery (GKRS).

Methods

The authors performed a retrospective analysis of 106 cases involving patients treated for typical trigeminal neuralgia using GKRS. Patients with or without single-vessel impingement on CISS MR imaging sequences and with no previous surgery were included in the study. Pain relief was assessed according to the Barrow Neurological Institute (BNI) pain intensity score at the last follow-up. Degree of impingement, nerve diameter preand post-impingement, isocenter placement, and dose to the point of maximum impingement were evaluated in relation to the improvement of BNI score.

Results

The overall median follow-up period was 31 months. Overall, a BNI pain score of 1 was achieved in 59.4% of patients at last follow-up. Vessel impingement was seen in 63 patients (59%). There was no significant difference in pain relief between those with and without vascular impingement following GKRS (p > 0.05).

In those with vascular impingement on MR imaging, the median fraction of vessel impingement was 0.3 (range 0.04–0.59). The median dose to the site of maximum impingement was 42 Gy (range 2.9–79 Gy). Increased dose (p = 0.019) and closer proximity of the isocenter to the site of maximum vessel impingement (p = 0.012) correlated in a statistically significant fashion with improved BNI scores in those demonstrating vascular impingement on the GKRS planning MR imaging

Conclusions

Vascular impingement of the affected nerve was seen in the majority of patients with trigeminal neuralgia. Overall pain relief following GKRS was comparable in those with and without evidence of vascular compression on MR imaging. In subgroup analysis of those with MR imaging evidence of vessel impingement of the affected trigeminal nerve, pain relief correlated with a higher dose to the point of contact between the impinging vessel and the trigeminal nerve. Such a finding may point to vascular changes affording at least some degree of relief following GKRS for trigeminal neuralgia.
Toll-like receptor 4 expression during cerebral aneurysm formation
Authors: Aoki Tomohiro , Nishimura Masaki , Ishibashi Ryota , Kataoka Hiroharu , Takagi Yasushi , Hashimoto Nobuo
Published: October 2009

Object

The pathophysiological origin of cerebral aneurysms is closely associated with chronic inflammation in arterial walls. Recently, the authors identified nuclear factor–kappa B (NF-κB) as a key mediator of cerebral aneurysm formation and progression. Because Toll-like receptor 4 (TLR4) stimulates NF-κB activation in arterial walls in atherosclerosis, the authors hypothesize that TLR4 expresses in cerebral aneurysms and contributes to the activation of NF-κB in cerebral aneurysm walls.

Methods

Cerebral aneurysms were induced in male Sprague-Dawley rats. Expression of TLRs in cerebral aneurysm walls was assessed using reverse transcriptase polymerase chain reaction (RT-PCR). The expression of TLR4 was examined using RT-PCR, immunohistochemical studies, and Western blotting. To assess TLR4 dependency on NF-κB activation, double immunostaining and a study using NF-κB–deficient mice were done. Finally, TLR4 expression in human cerebral aneurysm walls was assessed using immunohistochemical studies.

Results

In cerebral aneurysm walls, TLR1, -4, -5, -6, -10, and -11 were expressed. Among them, TLR4 and TLR10 expression changed during cerebral aneurysm formation. Expression of TLR4 was predominantly in the endothelial cell layer of cerebral aneurysm walls, and was transitionally upregulated at the early stage of cerebral aneurysm formation. The TLR4 expression coincided well with NF-κB activation. In human cerebral aneurysms, TLR4 was also expressed in the endothelial cell layer, as it was in rats.

Conclusions

Toll-like receptor 4 was expressed in cerebral aneurysm walls both in rats and humans. This receptor may play a crucial role in cerebral aneurysm formation through NF-κB activation in endothelial cells. The results of the present study will shed new light on the pathogenesis of cerebral aneurysm formation.
Prevalence and impact of diffuse axonal injury in patients with moderate and severe head injury: a cohort study of early magnetic resonance imaging findings and 1-year outcome
Authors: Skandsen Toril , Kvistad Kjell Arne , Solheim Ole , Strand Ingrid Haavde , Folvik Mari , Vik Anne
Published: October 2009

Object

In this prospective cohort study the authors examined patients with moderate to severe head injuries using MR imaging in the early phase. The objective was to explore the occurrence of diffuse axonal injury (DAI) and determine whether DAI was related to level of consciousness and patient outcome.

Methods

One hundred and fifty-nine patients (age range 5–65 years) with traumatic brain injury, who survived the acute phase, and who had a Glasgow Coma Scale (GCS) score of 3–13 were admitted between October 2004 and August 2008. Of these 159 patients, 106 were examined using MR imaging within 4 weeks postinjury. Patients were classified into 1 of 3 stages of DAI: Stage 1, in which lesions were confined to the lobar white matter; Stage 2, in which there were callosal lesions; and Stage 3, in which lesions occurred in the dorsolateral brainstem. The outcome measure used 12 months postinjury was the Glasgow Outcome Scale–Extended (GOSE).

Results

Diffuse axonal injury was detected in 72% of the patients and a combination of DAI and contusions or hematomas was found in 50%. The GCS score was significantly lower in patients with “pure DAI” (median GCS Score 9) than in patients without DAI (median GCS Score 12; p < 0.001). The GCS score was related to outcome only in those patients with DAI (r = 0.47; p = 0.001). Patients with DAI had a median GOSE score of 7, and patients without DAI had a median GOSE score of 8 (p = 0.10). Outcome was better in patients with DAI Stage 1 (median GOSE Score 8) and DAI Stage 2 (median GOSE Score 7.5) than in patients with DAI Stage 3 (median GOSE Score 4; p < 0.001). Thus, in patients without any brainstem injury, there was no difference in good recovery between patients with DAI (67%) and patients without DAI (66%).

Conclusions

Diffuse axonal injury was found in almost three-quarters of the patients with moderate and severe head injury who survived the acute phase. Diffuse axonal injury influenced the level of consciousness, and only in patients with DAI was GCS score related to outcome. Finally, DAI was a negative prognostic sign only when located in the brainstem.
High Fat and Highly Thermolyzed Fat Diets Promote Insulin Resistance and Increase DNA Damage in Rats
Authors: de Assis Adriano M. , Rieger Débora K. , Longoni Aline , Battu Cintia , Raymundi Suzeli , da Rocha Ricardo F. , Andreazza Ana C. , Farina Marcelo , Rotta Liane N. , Gottfried Carmen , Gonçalves Carlos A. , Moreira José Cláudio , Perry Marcos L. S.
Published: October 2009

Many studies have demonstrated that DNA damage may be associated with type 2 diabetes mellitus (T2DM) and its complications. The goal of this study was to evaluate the effects of the potential relationship between fat (thermolyzed) intake, glucose dyshomeostasis and DNA injury in rats. Biochemical parameters related to glucose metabolism (i.e., blood glucose levels, insulin tolerance tests, glucose tolerance tests and fat cell glucose oxidation) and general health parameters (i.e., body weight, retroperitoneal and epididymal adipose tissue) were evaluated in rats after a 12-month treatment with either a high fat or a high thermolyzed fat diet. The high fat diet (HFD) and high fat thermolyzed diet (HFTD) showed increased body weight and impaired insulin sensitivity at the studied time-points in insulin tolerance test (ITT) and glucose tolerance test (GTT). Interestingly, only animals subjected to the HFTD diet showed decreased epididymal fat cell glucose oxidation. We show which high fat diets have the capacity to reduce glycogen synthesis by direct and indirect pathways. HFTD promoted an increase in lipid peroxidation in the liver, demonstrating significant damage in lipids in relation to other groups. Blood and hippocampus DNA damage was significantly higher in animals subjected to HFDs, and the highest damage was observed in animals from the HFTD group. Striatum DNA damage was significantly higher in animals subjected to HFDs, compared with the control group. These results show a positive correlation between high fat diet, glucose dyshomeostasis, oxidative stress and DNA damage.
The IL-8 Production by Streptococcal Pyrogenic Exotoxin B
Authors: Chang Chia-Wen , Wu Siang-Yu , Chuang Woei-Jer , Lin Yee-Shin , Wu Jiunn-Jong , Liu Ching-Chuan , Tsai Pei-Jane , Lin Ming-T.
Published: October 2009

We have previously identified αvβ3and Fas as receptors for the streptococcal pyrogenic exotoxin B (SPE B), and G308S, a mutant of SPE B with RSD motif, which interacts with Fas only. This study aims to evaluate how SPE B interacts with cells to induce the production of IL-8. Our results showed that following exposure to SPE B or G308S, the levels of IL-8 protein and mRNA were increased and the increase was inhibited by the addition of anti-Fas antibody, suggesting that the increased production of IL-8 by SPE B is mediated through Fas receptor. In the presence of G308S, the association of FADD and procaspase 8, and activation of NF-κB were also detected. The application of siRNA of FADD and of procaspase 8 could inhibit the NF-κB activity. The proteolytic activity of caspase 8 was required for the NF-κB activity. Further studies showed that G308S could increase the phosphorylation of ERK and the translocation of NF-κB into the nucleus, and the inhibition of ERK phosphorylation decreased the IL-8 production, mRNA expression and activation of NF-κB. In addition, siRNA of procaspase 8 could inhibit the G308S-induced cleavage of MEKK1, binding of MEKK1 to caspase 8, activation of ERK and the NF-κB activity. Taken together, the production of IL-8 by SPE B in A549 cells is mediated by Fas, and followed by the activation of FADD, caspase 8, MEKK1, ERK and NF-κB.