bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and residual stress variations in weld zone of flash-butt welded railroads
Authors: Mansouri H. , Monshi A.
Published: July 2004

In the weld zone and base metal contiguous to the weld zone in flash-butt welded rail, the web of the rail has high tensile residual stresses and the head and base of the rail have compressive residual stresses. The web region is susceptible to failure since most of the weld zone of the rail is coarse grained and has porosity, inclusions and defects resulting from rapid solidification of molten metal entrapment in the weld. Efforts to reduce the amount of these tensile residual stresses require recognition of their causes. In this research, microscopic and macroscopic studies were carried out on vertical and horizontal sections of the weld zone in the head, web and base of the rail. Just after flash-butt welding, the temperature of the web between the current carrying copper electrodes is higher than the temperature of the head and base of the rail. Therefore, by cooling the weld zone to room temperature, the amount of web contraction between the electrodes is higher than the amount of base and head contraction and consequently tensile residual stresses are produced in the web at and near the weld zone. In the head and base of the rail, compressive residual stresses are developed.
Joining stainless steel metal foams
Authors: Shirzadi A.A. , Kocak M. , Wallach E.R.
Published: July 2004

Metallic foams produced from stainless steel are one of the most recently developed ultralightweight materials. These foams have very low densities and high energy absorption capacities and are therefore expected to have widespread applications in the manufacture of ultralightweight structural components. The fabrication of load bearing structural components such as implants, and high temperature air or fluid filters, are potential application areas depending on the form of the cell structure of the foam. Closed cell metal foams are typically suitable for structural uses whereas open cell foams tend to be preferred for functional applications. Development of adequate joining technologies for these materials is an essential step for their widespread industrial utilisation. The present paper describes a brazing method that is capable of providing excellent joints between 316 stainless steel foams and a conventional 316 stainless steel bulk alloy. Having optimised the bonding conditions and using a Cu–Ti alloy as the filler metal, bonds between a foam and a bulk alloy were produced. No apparent plastic deformation of the metal foam occurred in the course of the 10 min length brazing process, and the resulting bonds had tensile strengths higher than that of the stainless steel foam.
Interface structure and strength of brazed joints between TiC ceramic and iron
Authors: Zhang L. , Feng J. , Li Z. , Liu H.
Published: July 2004

The brazing of TiC ceramic to iron was carried out at 1123–1273 K for 5–20 min using Ag–Cu–Zn filler metal. Interface structure and shear strength of joints were investigated, the former via electron probe microanalysis, scanning electron microscopy, and X-ray diffraction, and the latter via the shearing method. The results show the formation of three phases in the TiC ceramic–iron joint, namely, copper base solid solution, FeNi, and silver base solid solution. The highest joint shear strength of 256.5 MPa is obtained for a brazing temperature of 1173 K and brazing time of 5 min.
Weld porosity in containers for storage of plutonium containing materials
Authors: Daugherty W.L. , Cannell G.R.
Published: July 2004

An autogenous gas tungsten arc closure weld was developed for the US Department of Energy's primary container for the storage of plutonium bearing materials. The occurrence of porosity at the tie-in point of the closure weld was investigated. The primary cause of the porosity was linked to the geometry at the root of the closure weld joint. The present paper describes the mechanistic model that was developed to describe and predict the porosity.
Influence of pre- and post-weld heating on weldability of modified 9Cr–1Mo(V–Nb) steel pipe under shielded metal arc and tungsten inert gas welding processes
Authors: Ghosh P.K. , Singh U.
Published: July 2004

Welding of modified 9Cr–1Mo(V–Nb) steel pipes has been carried out via shielded metal arc (SMA) and tungsten inert gas (TIG) welding processes. The weld joints have been produced using different preheating temperatures, followed by post-weld heat treatment (PWHT) at various temperatures. The microstructures of the weld and of the heat affected zone (HAZ) of the weld joints have been studied under the optical microscope and correlated with the preheating and PWHT. The average hardness of the weld and different regions of the HAZ, and tensile properties of the weld joints have also been studied and correlated with the preheating and PWHT. The tensile properties of the SMA and TIG weld joints produced using preheating and PWHT at various temperatures are compared and correlated with their microstructures. It is noted that a comparatively high preheating temperature of the order of 573 K is beneficial, and PWHT is necessary to reduce the susceptibility to cold cracking of weld joints of the present steel. The PWHT at 1123 K enhances ductility to fracture, but decreases the tensile strength of the base material, causing fracture of both the SMA and TIG weld joints from this region close to the HAZ. The tensile properties of SMA welds are found to be superior to those of the TIG welds, especially for PWHT at temperatures up to 1023 K.
Characterisation of pipe welds and HAZ in primary heat transport system piping of pressurised heavy water reactors
Authors: Ghosh P.K. , Singh P.K. , Vaze K.K. , Kushwaha H.S.
Published: July 2004

Weld joints of SA 333 Gr. 6 steel pipe have been prepared using GTAW root pass and SMAW filling of V-groove according to welding procedure specifications (WPS) conforming to ASME Sec IX, a procedure commonly used to fabricate nuclear piping system components. The objective of the present study was to characterise the base metal, weld deposit and HAZ of the pipe weld in terms of their chemical composition and metallurgical, mechanical and fracture mechanics properties. The fracture toughness behaviour of the welds and HAZ has been characterised by J-integral parameters. The fatigue crack growth rate has been characterised by Paris Law. The stretched zone width (SZW) at the fracture surface has been measured with SEM to evaluate the initiation fracture toughness. The values of initiation fracture toughness estimated on the basis of SZW and blunting line from EGF recommendation have been compared. The fracture mechanics properties of the base metal, weld and HAZ have been compared and correlated. Fracture mechanics properties of the weld and HAZ have also been correlated with microstructure.
Brazing with (NiCoCr)–B–Si amorphous brazing filler metals: Alloys, processing, joint structure, properties, applications
Authors: Rabinkin A.
Published: July 2004

This paper is a detailed and updated review of the properties and specifics of METGLAS amorphous brazing foil (MBF) and a review of the positive qualities it has brought to many applications in the last two decades. The major emphasis is to provide practical guidance for intelligent use that will contain, in the first part, a description of these materials in the virgin as cast state. This state has a unique combination of physical properties. The metallurgical background will also be given in this part to the existing range of available chemical compositions and their potential compatibility with various base metals. The amorphous alloy mechanical properties and thermal stability, wettability over various metals and its dependence on the brazing atmosphere and preform preparation will also be described. The second part presents the properties of MBF joints manufactured from various classes of base metals and obtained under optimised brazing conditions for each class of base metals. Particular attention is given to the joint microstructure/properties relationships yielding brazements with high strength, ductility and corrosion and fatigue resistance. Finally, the versatile technical and manufacturing features of MBF are underlined. These features are the driving force behind the rapid expansion of their applications in various industries. Examples of these applications are also given.
Prediction of weld quality in pulsed current GMAW process using artificial neural network
Authors: De A. , Jantre J. , Ghosh P.K.
Published: July 2004

Weld joint dimensions and weld metal mechanical properties are important quality characteristics of any welded joint. The success of building these characteristics in any welding situation depends on proper selection-cum-optimisation of welding process parameters. Such optimisation is critical in the pulsed current gas metal arc welding process (GMAW-P), as the heat input here is closely dictated by a host of additional pulse parameters in comparison to the conventional gas metal arc welding process. Neural network based models are excellent alternatives in such situations where a large number of input conditions govern certain outputs in a manner that is often difficult to adjudge a priori. Six individual prediction models developed using neural network methodology are presented here to estimate ultimate tensile strength, elongation, impact toughness, weld bead width, weld reinforcement height and penetration of the final weld joint as a function of four pulse parameters, e.g. peak current, base current, pulse on time and pulse frequency. The experimental data employed here are for GMAW-P welding of extruded sections of high strength Al–Zn–Mg alloy (7005). In each case, a committee of different possible network architectures is used, including the final optimum network, to assess the uncertainty in estimation. The neural network models developed here could estimate all the outputs except penetration fairly accurately.
Influences of post-weld heat treatment on fatigue crack growth behaviour of strength mismatched HSLA steel welds
Authors: Ravi S. , Balasubramanian V. , Nemat Nasser S.
Published: July 2004

Welding of high strength low alloy steels (HSLA) involves usage of low, even and high strength filler materials (electrodes) compared with the parent material depending on the application of the welded structures and the availability of the filler material. In the present investigation, the influences of post-weld heat treatment (PWHT) on fatigue crack growth behaviour of under matched (UM), equal matched (EM) and over matched (OM) weld metals has been studied. The base material used in this investigation is HSLA-80 steel of weldable grade. The Shielded Metal Arc Welding (SMAW) process has been used to fabricate the single ‘V’ butt joints. Centre Cracked Tension (CCT) specimens have been used to evaluate the fatigue crack growth behaviour of the welded joints. Fatigue crack growth experiments have been conducted using servo hydraulic controlled fatigue testing machine at constant amplitude loading (R = 0). From this investigation, it has been found that the fatigue performance of over matched joints is superior compared to under matched and equal matched joints. Moreover, PWHT reduced the magnitude of the tensile residual stress field in the weld region and subsequently enhanced the fatigue performance of the joints irrespective of weld metal strength mismatch.
Weld shape comparison with iron oxide flux and Ar–O2 shielding gas in gas tungsten arc welding
Authors: Lu S.-P. , Fujii H. , Nogi K.
Published: July 2004

The influence of iron oxide flux and O2–Ar mixed shielding gas on weld shape and penetration in gas tungsten arc welding is investigated by bead-on-plate welding on SUS 304 stainless with low oxygen and low sulphur contents. The oxygen content in the weld metal is measured using a HORIBA EMGA-520 oxygen/nitrogen analyzer. The results show that both the iron oxide flux and the O2–Ar mixed shielding gas can significantly modify the weld shape from shallow wide to deep narrow. A large weld depth/width ratio around of 0.5 is obtained when the oxygen content in the shielding gas is in the range of 3000–6000 vol. ppm. Oxygen over a certain critical value, i.e. 70 wt. ppm, in the weld pool alters the temperature coefficient of the surface tension on the pool surface, and hence changes the Marangoni convection. A thick oxide layer on the weld pool surface is generated when the oxygen content in the shielding gas is over 6000 vol. ppm, which becomes a barrier for the oxygen conveyance to the liquid pool and prevents the liquid pool from freely moving, and therefore, decreases the intensity of the Marangoni convection on the pool surface.
Improving the scaling normalization for high-density oligonucleotide GeneChip expression microarrays
Authors: Lu Chao
Published: July 2004

Background

Normalization is an important step for microarray data analysis to minimize biological and technical variations. Choosing a suitable approach can be critical. The default method in GeneChip expression microarray uses a constant factor, the scaling factor (SF), for every gene on an array. The SF is obtained from a trimmed average signal of the array after excluding the 2% of the probe sets with the highest and the lowest values.

Results

Among the 76 U34A GeneChip experiments, the total signals on each array showed 25.8% variations in terms of the coefficient of variation, although all microarrays were hybridized with the same amount of biotin-labeled cRNA. The 2% of the probe sets with the highest signals that were normally excluded from SF calculation accounted for 34% to 54% of the total signals (40.7% ± 4.4%, mean ± sd). In comparison with normalization factors obtained from the median signal or from the mean of the log transformed signal, SF showed the greatest variation. The normalization factors obtained from log transformed signals showed least variation.

Conclusions

Eliminating 40% of the signal data during SF calculation failed to show any benefit. Normalization factors obtained with log transformed signals performed the best. Thus, it is suggested to use the mean of the logarithm transformed data for normalization, rather than the arithmetic mean of signals in GeneChip gene expression microarrays.
Phylogenetic relationships of typical antbirds (Thamnophilidae) and test of incongruence based on Bayes factors
Authors: Irestedt Martin , Fjeldså Jon , Nylander Johan AA , Ericson Per GP
Published: August 2004

Background

The typical antbirds (Thamnophilidae) form a monophyletic and diverse family of suboscine passerines that inhabit neotropical forests. However, the phylogenetic relationships within this assemblage are poorly understood. Herein, we present a hypothesis of the generic relationships of this group based on Bayesian inference analyses of two nuclear introns and the mitochondrial cytochrome b gene. The level of phylogenetic congruence between the individual genes has been investigated utilizing Bayes factors. We also explore how changes in the substitution models affected the observed incongruence between partitions of our data set.

Results

The phylogenetic analysis supports both novel relationships, as well as traditional groupings. Among the more interesting novel relationship suggested is that the Terenura antwrens, the wing-banded antbird (Myrmornis torquata), the spot-winged antshrike (Pygiptila stellaris) and the russet antshrike (Thamnistes anabatinus) are sisters to all other typical antbirds. The remaining genera fall into two major clades. The first includes antshrikes, antvireos and the Herpsilochmus antwrens, while the second clade consists of most antwren genera, the Myrmeciza antbirds, the "professional" ant-following antbirds, and allied species. Our results also support previously suggested polyphyly of Myrmotherula antwrens and Myrmeciza antbirds. The tests of phylogenetic incongruence, using Bayes factors, clearly suggests that allowing the gene partitions to have separate topology parameters clearly increased the model likelihood. However, changing a component of the nucleotide substitution model had much higher impact on the model likelihood.

Conclusions

The phylogenetic results are in broad agreement with traditional classification of the typical antbirds, but some relationships are unexpected based on external morphology. In these cases their true affinities may have been obscured by convergent evolution and morphological adaptations to new habitats or food sources, and genera like Myrmeciza antbirds and the Myrmotherula antwrens obviously need taxonomic revisions. Although, Bayes factors seem promising for evaluating the relative contribution of components to an evolutionary model, the results suggests that even if strong evidence for a model allowing separate topology parameters is found, this might not mean strong evidence for separate gene phylogenies, as long as vital components of the substitution model are still missing.
A molecular 'signature' of primary breast cancer cultures; patterns resembling tumor tissue
Authors: Dairkee Shanaz H , Ji Youngran , Ben Yong , Moore Dan H , Meng Zhenhang , Jeffrey Stefanie S
Published: July 2004

Background

To identify the spectrum of malignant attributes maintained outside the host environment, we have compared global gene expression in primary breast tumors and matched short-term epithelial cultures.

Results

In contrast to immortal cell lines, a characteristic 'limited proliferation' phenotype was observed, which included over expressed genes associated with the TGFβ signal transduction pathway, such as SPARC, LOXL1, RUNX1, and DAPK1. Underlying this profile was the conspicuous absence of hTERT expression and telomerase activity, a significant increase in TβRII, its cognate ligand, and the CDK inhibitor, p21
CIP1/WAF1
. Concurrently, tumor tissue and primary cultures displayed low transcript levels of proliferation-related genes, such as, TOP2A, ANKT, RAD51, UBE2C, CENPA, RRM2, and PLK.

Conclusions

Our data demonstrate that commonly used immortal cell lines do not reflect some aspects of tumor biology as closely as primary tumor cell cultures. The gene expression profile of malignant tissue, which is uniquely retained by cells cultured on solid substrates, could facilitate the development and testing of novel molecular targets for breast cancer.
Diagnostic accuracy of ultrasonography compared to unenhanced CT for stone and obstruction in patients with renal failure
Authors: Ather M Hammad , Jafri Aftab H , Sulaiman M Nasir
Published: July 2004

Background

To determine accuracy of ultrasound (US) kidney, ureter and bladder (KUB) compared to un-enhanced helical CT (UHCT) in patients with renal failure in the diagnosis of stone and obstruction.

Methods

This is a case controlled study conducted in the period from June 2000 to July 2003 at a university hospital. All patients had both US and UHCT scan. Patients with serum creatinine ≥ 1.8 mg/dl were included in the study. Only direct visualization of stone was considered as confirmatory. In both the studies, UHCT and US, presence of stone and obstruction were noted. The relevant biochemicals, radiological and clinical records of all the patients were analyzed. Data was analyzed using commercially available software.

Results

During the period of study 864 patients had UHCT for evaluation of the urinary tract in patients presenting with flank pain. Out of these 34 patients had both UHCT and US done within a span of one day and had serum creatinine of ≥1.8 mg/dl. Mean age was 48 ±15.8 years and 59% of patients were males. UHCT identified renal stones in 21 (62%), whereas 17 of these were identified on US, with a sensitivity of 81%. Of the four patients with renal stones missed on US, three were identified on plain x-ray; the mean size of stones missed was 6.3 mm. Of the 22 (65%) patients with ureteric stone on UHCT, US could only identify 10; a further 7 were identified on x-ray KUB, giving a sensitivity of 45% (US alone) and 77% (US with x-ray KUB).

Conclusions

US is sensitive and specific for renal stones, 81% and 100% and for hydronephrosis, 93% and 100%, respectively. Its sensitivity to pick ureteric stone (46%) and to identify hydroureter (50%) is low. Addition of x-ray KUB abdomen increases the sensitivity for ureteric stones to 77%.
Use and improvement of microbial redox enzymes for environmental purposes
Authors: Garcia-Arellano Humberto , Alcalde Miguel , Ballesteros Antonio
Published: August 2004

Industrial development may result in the increase of environmental risks. The enzymatic transformation of polluting compounds to less toxic or even innocuous products is an alternative to their complete removal. In this regard, a number of different redox enzymes are able to transform a wide variety of toxic pollutants, such as polynuclear aromatic hydrocarbons, phenols, azo dyes, heavy metals, etc. Here, novel information on chromate reductases, enzymes that carry out the reduction of highly toxic Cr(VI) to the less toxic insoluble Cr(III), is discussed. In addition, the properties and application of bacterial and eukaryotic proteins (lignin-modifying enzymes, peroxidases and cytochromes) useful in environmental enzymology is also discussed.
Failed attempts at experimental transplantation and transmission of nocturnally-periodic simian Loafrom monkey to man
Authors: Duke BOL
Published: July 2004

This paper describes unsuccessful attempts to induce a nocturnally-periodic infection with simian Loa in a human volunteer (the author of this paper) by means of 1. Transplanting adult simian Loa worms from a wild drill (Mandrillus leucophaeus) to man; and 2. Infecting the same volunteer by sub-cutaneous inoculation with infective larvae of simian Loa from a laboratory-bred, experimentally infected Chrysops silacea.
Insights into the pathogenesis of vein graft disease: lessons from intravascular ultrasound
Authors: Murphy Gavin J , Angelini Gianni D
Published: July 2004

The success of coronary artery bypass grafting (CABG) is limited by poor long-term graft patency. Saphenous vein is used in the vast majority of CABG operations, although 15% are occluded at one year with as many as 50% occluded at 10 years due to progressive graft atherosclerosis. Intravascular ultrasound (IVUS) has greatly increased our understanding of this process. IVUS studies have shown that early wall thickening and adaptive remodeling of vein grafts occurs within the first few weeks post implantation, with these changes stabilising in angiographically normal vein grafts after six months. Early changes predispose to later atherosclerosis with occlusive plaque detectable in vein grafts within the first year. Both expansive and constrictive remodelling is present in diseased vein grafts, where the latter contributes significantly to occlusive disease. These findings correlate closely with experimental and clinicopathological studies and help define the windows for prevention, intervention or plaque stabilisation strategies. IVUS is also the natural tool for evaluating the effectiveness of pharmacological and other treatments that may prevent or slow the progression of vein graft disease in clinical trials.
Small B cell lymphocytic lymphoma presenting as obstructive sleep apnea
Authors: Tsou Yung-An , Cheng Yuan-Kai , Lin Chia-Der , Chang Weng-Cheng , Tsai Ming-Hsui
Published: July 2004

Background

Most lymphomas that involve the tonsil are large B cell lymphomas. Large B-cell lymphoma is a high grade malignancy which progresses rapidly. Tonsillar lymphoma usually presents as either a unilaterally enlarged palatine tonsil or as an ulcerative and fungating lesion over the tonsillar area. Small lymphocytic lymphomas (SLL) of the Waldeyer's ring are uncommon.

Case presentation

We report a 41-year-old male who presented with a ten-year history of snoring. Physical examination revealed smooth bilateral symmetrically enlarged tonsils without abnormal surface change or cervical lymphadenopathy. Palatal redundancy and a narrowed oropharyngeal airway were also noted. The respiratory disturbance index (RDI) was 66 per hour, and severe obstruction sleep apnea (OSA) was suspected. No B symptoms, sore throat, odynophagia or dysphagia was found. We performed uvulopalatopharyngoplasty (UPPP) and pathological examination revealed incidental small B-cell lymphocytic lymphoma (SLL).

Conclusion

It is uncommon for lymphoma to initially present as OSA. SLL is an indolent malignancy and is not easy to detect in the early stage. We conclude that SLL may be a contributing factor of OSA in the present case.
Cancer immunotherapy: avoiding the road to perdition
Authors: Chiriva-Internati Maurizio , Grizzi Fabio , Bright Robert K. , Kast W. Martin
Published: July 2004

The hypothesis that human cancers express antigens that can be specifically targeted by cell mediated immunity has become a scientifically justifiable rationale for the design and clinical testing of novel tumor-associated antigens (TAA). Although a number of TAA have been recognized and it has been suggested that they could be useful in the immunological treatment of cancer, the complexity of human beings leads us to reflect on the need to establish new criteria for validating their real applicability. Herein, we show a system level-based approach that includes morphological and molecular techniques, which is specifically required to improve the capacity to produce desired results and to allow cancer immunotherapy to re-emerge from the mist in which it is currently shrouded.
Lighting in outer space: a review of the research and development of the exterior luminaires and lamps for the International Space Station
Authors: Lewin I
Published: July 2004

,!With the launch and assembly of the International Space Station, it has become necessary to provide lighting systems that can survive and operate in the outer space environment. Floodlights are required while astronauts are outside the Space Station, performing assembly, maintenance and experimentation. Larger floodlights also are required for the various video camera systems on the station’s exterior. This paper describes both the lamp and luminaire development for the systems. It discusses simulation of microgravity conditions on Earth needed to evaluate high intensity discharge lamp performance. The paper covers aspects of the mechanical and photometric design of the equipment. The effects of atomic oxygen, micrometeorite bombardment, thermal extremes, cosmic and gamma rays, corona and ultraviolet bombardment are considered. Details and specifications of the lamps and luminaires are provided.
A review of colour rendering indices and their application to commercial light sources
Authors: Guo Xin , Houser KW
Published: July 2004

,!The CIE colour rendering index (Ra) is the most widely used measure for quantifying and comparing the colour rendering performance of light sources. Despite its prominence Ra is not without limitations, including its reliance on reference standards and the inability to compare the Ra of sources with different correlated colour temperatures. Other colour rendering measures have been proposed including several based on colour preference, others based on absolute scales, and some that are graphical rather than numerical. This paper utilizes nine colour rendering indices to assess and compare the performance of common light sources and theoretical illuminants. Following this assessment, recommendations for the use of existing tools are made, as well as suggested strategies for future colour rendering measures.
Brightness, lightness, and providing ‘a preconceived appearance to the interior’
Authors: Cuttle C
Published: July 2004

,!Waldram’s concept of designing a distribution of lighting to provide ‘a preconceived appearance to the interior’ is examined, with particular regard to application of the ‘apparent brightness’ concept. Some recent research into luminance/brightness relationships is reviewed, and it is concluded that brightness, as it is generally understood, does not provide a valid basis for designing interior lighting. The role of ‘visual constancy’ is discussed, and also the ‘modes of appearance’ concept. The latter is proposed as a useful descriptive framework for ordering readily-observed visual phenomena that influence the appearance elements in an illuminated interior. This approach leads to an understanding that brightness and lightness relate to distinctly different aspects of appearance, and this leads to the reappraisal of the role of brightness in influencing the appearance of an illuminated space. These concepts are set into the context of the holistic approach to lighting design that Waldram proposed in his classic 1954 paper.
The illuminated surface areas of high-intensity discharge and tungsten halogen headlamps in the USA
Authors: Schoettle B , Sivak M , Flannagan MJ , Adachi G
Published: July 2004

,!This study was designed to compare the illuminated surface areas of high-intensity discharge (HID) and tungsten halogen low-beam headlamps in the USA. A sample of 20 tungsten halogen lamps and 17 HID lamps for model year 2000 vehicles in the US was examined. The illuminated surface area was determined using a modified version of an Economic Commission for Europe (ECE) method for evaluating the illuminated surface of signalling devices. The main finding is that the HID low (passing) beams generally have smaller illuminated surface areas than do the tungsten halogen low beams. Because smaller light sources result in more discomfort glare (presumably via greater luminance), the present finding suggests that the smaller illuminated area is one reason for drivers reporting more discomfort from HID lamps. An implication is that the increased discomfort from HID lamps could be reduced by increasing their illuminated surface area.
Verification of program accuracy for illuminance modelling: assumptions, methodology and an examination of conflicting findings
Authors: Mardaljevic J
Published: July 2004

,!This paper examines the role of assumptions commonly made in validation studies for lighting simulation programs and quantifies the sensitivity of results to uncertainties in key model parameters such as sky conditions and surface reflectivity. Actually occurring overcast skies are often taken to approximate the CIE standard overcast sky for the purpose of comparing predictions against measurements in real buildings. The validity of this assumption is tested against measurements of the sky luminance distribution for real skies. Illuminance predictions are particularly sensitive to the assigned reflectance of surfaces when the direct component of illumination is small. A number of confounding factors that can lead to imprecise estimates of surface reflectivity for building facades are identified and a methodology to minimize their effect is proposed. This study reveals that commonly made assumptions with respect to sky conditions and moderate imprecision in model parameters can lead to erroneous assessments of program accuracy. The degree to which existing validation findings can be extrapolated to very different application scenarios is discussed in the context of reported conflicting assessments of program accuracy.
Quantitative Validation of a General Competency Composite Assessment Evaluation
Authors: Reisdorff Earl J. , Carlson Dale J. , Reeves Mat , Walker Gregory , Hayes Oliver W. , Reynolds Brian
Published: August 2004

Objectives: The authors sought to modify and validate a composite assessment evaluation process that assesses resident acquisition of the Accreditation Council for Graduate Medical Education (ACGME) general competencies (GCs). Methods:This study critically analyzed the evaluation process used in a multicenter study (150 emergency medicine resident evaluations) to determine whether the procedure was psychometrically valid. For each GC, principal component analysis (PCA) was used to determine whether certain evaluation items could be eliminated, as well as to determine the magnitude of variability explained by up to three linear combinations or “principal components.” The factor proportions (factor loadings) of various eigenvectors were measured to determine the degree of variability (determined by the square of the factor proportion) within a data or item set. The factor proportions essentially measure the length of the eigenvector as determined from a correlation matrix. Results: The first three principal components are reported as factor proportion sum (% of total variability) as follows: patient care 0.91 (83%), medical knowledge 0.87 (76%), practice‐based learning and improvement 0.90 (81%), interpersonal and communication skills 0.84 (71%), professionalism 0.74 (55%), and systems‐based practice 0.80 (64%). PCA showed that evaluating certain traditional categories such as medical knowledge seemed to capture a single element, whereas professionalism appeared to measure a more complex, multidimensional phenomenon. Conclusions: By using a structured development process, the authors were able to create valid evaluation items for determining resident acquisition of the ACGME GCs.
Patient and Primary Care Physician Satisfaction with Chest Pain Unit and Routine Care
Authors: Goodacre Steve W. , Quinney Deborah , Revill Sue , Morris Francis , Capewell Simon , Nicholl Jon
Published: August 2004

Objectives: The chest pain unit (CPU) has been developed to improve care for patients with acute, undifferentiated chest pain. The authors aimed to measure patient and primary care physician (PCP) satisfaction with CPU care and routine care and to determine whether patient satisfaction predicted PCP satisfaction. Methods: A CPU was established, and 442 days were randomly allocated to either CPU care or routine care. Consenting patients presenting with acute, undifferentiated chest pain were recruited and followed at two days and one month. All were given a self‐completed patient satisfaction questionnaire two days after attendance (N= 972). Each patient's PCP was sent a self‐completed satisfaction questionnaire during days 171–442 of the trial (N= 601). Analysis determined whether CPU care was associated with improved patient or PCP satisfaction and whether patient satisfaction predicted PCP satisfaction for three questions relating to diagnosis, treatment, and overall care. Results: CPU care was consistently associated with higher scores across all patient satisfaction questions, from the perceived thoroughness of examination to care received to an overall assessment of the service received. However, CPU care achieved small improvements in only two of ten PCP satisfaction questions, concerning overall management of the patient and the amount of information about investigations performed. Furthermore, patient satisfaction did not predict PCP satisfaction in relation to diagnosis (p = 0.456), treatment (p = 0.256), or overall care (p = 0.085). Conclusions: CPU care is associated with substantial improvements in all dimensions of patient satisfaction but only minimal improvements in PCP satisfaction. Patient satisfaction was not a strong predictor of PCP satisfaction with emergency care.
Society for Academic Emergency Medicine Survey of the Association of American Medical Colleges Council of Academic Societies
Authors: Martin Marcus L. , Blevins Tiffany , O'Connor Victoria , Pines Jesse , Srinivasan Rajagopalan
Published: August 2004

The Society for Academic Emergency Medicine (SAEM) surveyed the Council of Academic Societies (CAS) organizations to obtain useful information to project SAEM goals into the year 2010. The objective of this work was to understand common and varying organizational operations and identify opportunities. The authors reviewed CAS organizations' mission statements, operating budgets, modes of communications, products, meeting formats, foundations, endowment funds, staff structures, headquarters, advocacy activities (services), top challenges, and most significant changes anticipated the next ten years. The survey methodology was used to gain insight into modes of operation of CAS organizations and enable SAEM to review its own operations and identify potential organizational changes based on the experiences of others. Individual CAS organizations might similarly benefit by reviewing the results of the survey and comparing themselves with others.
Cocaine Use in Elder Patients Presenting to an Inner‐city Emergency Department
Authors: Rivers Emanuel , Shirazi Ehsan , Aurora Taruna , Mullen Marie , Gunnerson Kyle , Sheridan Brendan , Eichhorn Laura , Tomlanovich Michael
Published: August 2004

Objectives: To determine the prevalence of cocaine use in a population of elder patients presenting to an inner‐city academic emergency department (ED). Methods:This was a prospective, blinded observational study of patients aged 60 years or older who presented to a large urban ED over a six‐month period. A urine drug screen was performed on patients who had a sample obtained during treatment for routine analysis. Patients' demographic data were collected and compared. Results: A total of 5,677 visits met the inclusion criteria. Urine samples were obtained in 911 (16%) of these visits with 852 unique individuals. There were 18 cocaine‐positive results among the 911 visits, for a rate of 2.0%. The rate of positive subjects was also 2.0% (17/852). The cocaine users were younger (66.4 ± 7.2 vs. 76.0 ± 8.7 years), predominantly male (88.9% vs. 46.6%), and more likely to be diagnosed with drug or alcohol abuse as compared with the cocaine‐negative patients. However, there were no significant differences in disposition between the cocaine‐positive and cocaine‐negative groups. Conclusions: Elder patients may have a higher prevalence of cocaine use than previously estimated by national registries.
The Saliva Strip Test Is an Accurate Method to Determine Blood Alcohol Concentration in Trauma Patients
Authors: Degutis Linda C. , Rabinovici Reuven , Sabbaj Alfredo , Mascia Rebecca , D'Onofrio Gail
Published: August 2004

Objectives: To determine the accuracy of alcohol saliva testing (AST) in trauma patients. Methods:Blood alcohol concentration (BAC) was measured by using both AST (QED A350; STC Technologies, Bethlehem, PA) and blood serum levels in 100 trauma patients admitted to the emergency department of an urban Level 1 trauma center. Results: All 41 patients who tested positive for BAC on AST (mean [±SD]: 167.9 ± 16.16; range: 20–350 mg/dL) also tested positive on serum determination (mean: 197.6 ± 13.79; range: 22–446 mg/dL). Correlation between the two positive tests was significant (0.879, p < 0.001). Of the remaining 61 patients, 59 tested negative on both tests, while two patients with BACs of <30 mg/dL tested negative on the AST. For 18 patients with blood in the oropharynx, there was a correlation of 0.976 (p < 0.001, two‐tailed) between serum and AST tests. Conclusions: The AST method of measuring BAC in trauma patients is accurate. Blood in the oral cavity did not appear to affect the accuracy of the test.
Multiple Episodes of Mild Traumatic Brain Injury Result in Impaired Cognitive Performance in Mice
Authors: Creeley Catherine E. , Wozniak David F. , Bayly Philip V. , Olney John W. , Lewis Lawrence M.
Published: August 2004

Objectives: Results from recent studies on animal models of concussion suggest that multiple, rather than single, episodes of mild traumatic brain injury result in impaired cognitive performance in mice. The objective of the present study was to administer multiple impacts to the heads of mice while directly measuring the force of the impacts to determine how these parameters are related to transient loss of consciousness, cognitive deficits, and potential neuropathologic effects. Methods:Seven‐week‐old male C57BL/6 mice were randomly assigned to experimental conditions involving three impacts (weight‐drop method) to the head to induce mild traumatic brain injury or to sham control procedures. Some impacted (n= 10) and sham control (n= 10) mice were evaluated behaviorally and tested for spatial learning using the Morris water maze (MWM), whereas other impacted (n= 10) and sham control (n= 5) mice were used for histopathologic analysis. Results: The mean (± SD) force of impact was 19 (± 3.5) N. Impacted mice took longer to regain consciousness compared with sham control mice (p < 0.0005). Behavioral test results showed that the groups did not differ on activity or sensorimotor tests or during cued trials in the MWM. Impacted mice exhibited impaired spatial learning performance during place trials in the MWM (p < 0.05). Silver staining revealed a contra‐coup type of injury involving ventral brain structures in contact with or in close proximity to the skull. Conclusions: This multiple‐impact model, delivered within a specifiable force range, results in transient, reversible loss of consciousness, a contra‐coup brain injury, and cognitive impairment.
Clinical Factors Predicting Fractures Associated with an Anterior Shoulder Dislocation
Authors: Émond Marcel , Le Sage Natalie , Lavoie André , Rochette Louis
Published: August 2004

Objectives: To identify risk factors for fractures associated with an anterior shoulder dislocation treated in an emergency department (ED). Methods: A retrospective case–control study over five years of patients with an anterior shoulder dislocation was accomplished in a university‐affiliated ED. Chart review identified possible predictors of fractures. Comparing the profile of patients having a clinically important fracture associated with their shoulder dislocation (cases) with those sustaining a noncomplicated dislocation (controls) provided the outcome measure. Results: A total of 334 patients were included in the study. Eighty‐five (25.5%) had a clinically important fracture‐dislocation, and the remaining 249 (74.5%) sustained a noncomplicated shoulder dislocation. Chi‐square, logistic regression, and recursive partitioning analysis showed three significant factors for the presence of fracture‐dislocation: 1) age 40 years or older, 2) a first episode of dislocation, and 3) mechanism of injury (i.e., a fall greater than one flight of stairs, a fight/assault episode, or a motor vehicle crash). A multiple logistic regression model estimated the significant adjusted odds ratios (and their 95% confidence intervals [95% CIs]) for each of the three factors: 5.18 (95% CI = 2.74 to 9.78), 4.23 (95% CI = 1.82 to 9.87), and 4.06 (95% CI = 1.95 to 8.48), respectively. A predictive model using any one of the three factors reached a sensitivity of 97.7% (95% CI = 91.8% to 99.4%), a specificity of 22.9% (95% CI = 18.1% to 28.5%), and a negative predictive value of 96.6% (95% CI = 88.3% to 99.6%). Conclusions: Three risk factors predict clinically important fractures that are associated with shoulder dislocation: age, first episode, and mechanism of dislocation. A prospective validation may lead to standardized use of prereduction radiographs of the shoulder in the ED.
Bench to Bedside: HMGB1—A Novel Proinflammatory Cytokine and Potential Therapeutic Target for Septic Patients in the Emergency Department
Authors: Sama Andrew E. , D'Amore Jason , Ward Mary F. , Chen Guoqian , Wang Haichao
Published: August 2004

Overwhelming gram‐negative bacterial infection and life‐threatening systemic inflammation are widespread problems in critically ill emergency department patients. Currently, the treatment of these patients is largely supportive, focusing on antibiotics, fluids, hemodynamic and ventilatory support, and intensive monitoring. The only Food and Drug Administration‐approved pharmaceutical agent for the treatment of sepsis is activated protein C, with its use largely relegated to the intensive care unit. The subject thus remains an active area of exploration for emergency medicine research. During sepsis and inflammation, innate immune cells release excessive amounts of proinflammatory cytokines such as tumor necrosis factor (TNF) and interleukin‐1β. If delivered early enough, anti‐TNF antibodies can be an effective therapy in experimental models of septic shock. Anti‐TNF antibodies have been developed for clinical use in rheumatoid arthritis and Crohn's disease. However, anti‐TNF treatment for sepsis has been difficult to achieve in the clinical setting, perhaps because TNF's early release and transient appearance in the serum create a narrow therapeutic window. An alternative strategy would be to identify “late” mediators that may be clinically more accessible. High mobility group box 1 (HMGB1), a protein previously known only as a nuclear transcription factor, is now implicated as a late mediator of sepsis. Targeting late mediators of lethal systemic inflammation represents a novel approach that may widen the therapeutic window and lead to new strategies for inhibiting the deleterious effects of the inflammatory cascade. Here the authors review the studies that led to the discovery of HMGB1 as a late mediator of systemic inflammation and discuss the possibility of HMGB1 as a therapeutic target for septic patients in the emergency department.
The T-Box transcription factor Tbx5 is required for the patterning and maturation of the murine cardiac conduction system
Authors: Moskowitz Ivan P. G. , Pizard Anne , Patel Vickas V. , Bruneau Benoit G. , Kim Jae B. , Kupershmidt Sabina , Roden Dan , Berul Charles I. , Seidman Christine E. , Seidman Jonathan G.
Published: August 2004

We report a critical role for the T-box transcription factor Tbx5 in development and maturation of the cardiac conduction system. We find that Tbx5 is expressed throughout the central conduction system, including the atrioventricular bundle and bundle branch conduction system. Tbx5haploinsufficiency in mice (Tbx5del/+), a model of human Holt–Oram syndrome, caused distinct morphological and functional defects in the atrioventricular and bundle branch conduction systems. In the atrioventricular canal, Tbx5 haploinsufficiency caused a maturation failure of conduction system morphology and function. Electrophysiologic testing of Tbx5del/+ mice suggested a specific atrioventricular node maturation failure. In the ventricular conduction system, Tbx5 haploinsufficiency caused patterning defects of both the left and right ventricular bundle branches, including absence or severe abnormalities of the right bundle branch. Absence of the right bundle branch correlated with right-bundle-branch block by ECG. Deficiencies in the gap junction protein gene connexin 40 (Cx40), a downstream target of Tbx5, did not account for morphologic conduction system defects in Tbx5del/+ mice. We conclude that Tbx5 is required for Cx40-independent patterning of the cardiac conduction system, and suggest that the electrophysiologic defects in Holt–Oram syndrome reflect a developmental abnormality of the conduction system.
Disrupted gonadogenesis and male-to-female sex reversal inPod1knockout mice
Authors: Cui Shiying , Ross Andrea , Stallings Nancy , Parker Keith L. , Capel Blanche , Quaggin Susan E.
Published: August 2004

Congenital defects in genital and/or gonadal development occur in 1 in 1000 humans, but the molecular basis for these defects in most cases remains undefined. We show that the basic helix-loop-helix transcription factor Pod1(capsulin/epicardin/Tcf21) is essential for normal development of the testes and ovaries, and hence for sexual differentiation. The gonads of Pod1knockout (KO) mice were markedly hypoplastic, and the urogenital tracts of both XX and XY mice remained indistinguishable throughout embryogenesis. Within Pod1 KO gonads, the number of cells expressing the cholesterol side-chain cleavage enzyme (Scc) was increased markedly. Biochemical and genetic approaches demonstrated that Pod1 transcriptionally represses steroidogenic factor 1 (Sf1/Nr5a1/Ad4BP), an orphan nuclear receptor that regulates the expression of multiple genes (including Scc) that mediate sexual differentiation. Our results establish that Pod1 is essential for gonadal development, and place it in a transcriptional network that orchestrates cell fate decisions in gonadal progenitors.