bluuebunny/crossref_metadata_2025 huggingface dataset:
Matrix rheology effects on reaction rim growth I: evidence from orthopyroxene rim growth experiments
Authors: MILKE R. , ABART R. , KUNZE K. , KOCH‐MÜLLER M. , SCHMID D. , ULMER P.
Published: December 2008

The rim‐forming reaction quartz + olivine = orthopyroxene is used to investigate the effect of matrix rheology on rim growth rates. Orthopyroxene rim growth around olivine grains in quartz matrix is compared to rim growth around quartz grains in an olivine matrix. At constant P–T, within one single capsule, orthopyroxene rims grow faster around quartz clasts in olivine matrix than around olivine clasts in quartz matrix. Fourier transform infra‐red spectra indicate that the entire samples are water saturated because of water adsorption on the reactant grain surfaces. The increased orthopyroxene growth rates in olivine matrix as opposed to quartz matrix are interpreted in terms of matrix rheology, where in the two different matrix‐inclusion arrangements the olivine matrix behaves ‘softer’ and the quartz matrix ‘more rigid’. The strain energy associated with accommodation of the negative reaction volume is higher for the quartz than the olivine matrix and reduces the free energy that drives orthopyroxene rim growth. Growth textures in both kinds of orthopyroxene rims indicate that the diffusivity of MgO slightly exceeds the diffusivity of SiO2. The relative mobility of MgO and SiO2 at given P, T, fH2O seems to be controlled by energy minimization during orthopyroxene growth at the compressive Ol/Opx interface. Our experiments provide evidence for two previously overlooked effects relevant to rim growth reactions in metamorphic rocks: (i) diffusivity along chemical potential gradients to reaction sites is a function of rheology and (ii) the relative diffusivity of components during reaction rim or corona growth is a function of local volume changes at the rim’s interfaces.
Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model
Authors: SCHMID D. W. , ABART R. , PODLADCHIKOV Y. Y. , MILKE R.
Published: December 2008

Chemical reactions and phase changes generally involve volume changes. In confined settings this will cause a mechanical deformation of the matrix that surrounds the reaction sites where the volume change takes place. Consequently, mineral reactions and the mechanical response of the rock matrix are coupled. A companion paper in this issue illustrates this coupling with experiments where quartz and olivine react to form enstatite reaction rims under ambient conditions of 1 GPa and 1000 °C. It has been demonstrated that for identical run conditions, the thickness of the reaction rims depends on whether quartz grains are embedded in an olivine matrix or olivine grains are included in a quartz matrix. The experimental conditions, the nature of the results, and the large volume change of the reaction (−6%) leave only viscous creep as a viable matrix response to the reaction progress. A model is developed for this reaction, which combines diffusion of chemical components through the growing rim and viscous creep of the matrix. The resulting rate law for reaction rim growth in spherical geometry shows that the progress rate is proportional to the reaction overstepping and controlled by the slower of the two competing processes; either diffusion or creep. If diffusion is rate limiting the usual linear proportionality between rim growth and results. However, if viscous creep is rate limiting, then the reaction rates are reduced and may become effectively creep controlled. With respect to the experiments in the companion paper it is inferred that the effective viscosity of the two matrix materials, i.e. polycrystalline quartz and olivine, differ by approximately one order of magnitude with the quartz being the stronger one. The absolute values of the inferred viscosities correspond well to published flow laws. The rheological properties of natural rocks are well within the parameter range for which significant mechanical control on reaction rim growth is expected. This implies that for the interpretation of natural reaction rims and corona structures both diffusion and mechanical control need to be considered. In addition the mechanical effect also needs to be considered when interdiffusion coefficients are retrieved from rim growth experiments. This should also be considered for geospeedometry analyses. Furthermore, the control on reaction rate because of slow creep of the matrix is expected to be even more important, compared to the experiments, under colder crustal conditions and may contribute substantially to the frequent observation of only partially completed reactions. We suggest that this phenomenon is referred to as ‘mechanical closure’, which may be an important mechanism in the kinetic displacement of the boundaries between the stability fields of phase assemblages.
Plate movements, ductile deformation and geochronology of the Sanbagawa belt, SW Japan: tectonic significance of 89–88 Ma Lu–Hf eclogite ages
Authors: WALLIS S. R. , ANCZKIEWICZ R. , ENDO S. , AOYA M. , PLATT J. P. , THIRLWALL M. , HIRATA T.
Published: December 2008

Prograde P–T paths and thermal modelling suggest metamorphism in the Sanbagawa belt represents unusually warm conditions for subduction‐type metamorphic belts, and these likely reflect conditions of a convergent margin a few million years before the arrival of an active spreading ridge. Radiometric age data and kinematic indicators of ductile deformation suggest the Sanbagawa belt formed in a Cretaceous convergent margin associated with a plate movement vector that had a large sinistral oblique component with respect to the belt, the East Asian margin. Plate reconstructions for the Cretaceous to Tertiary for this region show that the only plausible plate compatible with such motion at this time is the Izanagi plate. These reconstructions also show that progressively younger sections of the Izanagi plate were subducted beneath eastern Asia, i.e. a spreading ridge approached, until 85–83 Ma when the Izanagi Plate ceased to exist as an independent plate. The major reorganization of plates and associated movements around this time is likely to be the age of major interaction between the ridge and convergent margin. The ridge‐approach model for the Sanbagawa metamorphism, therefore, predicts that peak metamorphism is a few million years older than this age range. New Lu–Hf dating of eclogite in the Sanbagawa belt gives ages of 89–88 Ma, in excellent agreement with the prediction. Combining this estimate for the peak age of metamorphism with published P–T‐t results implies vertical exhumation rates of greater than 2.5 cm yr−1. This high rate of exhumation can explain the lack of a significant thermal overprint in the Sanbagawa belt during subduction of the ridge.
Comparison of Simulation and Experiments of Different Closed‐Loop Strategies for Functional Electrical Stimulation: Experiments in Paraplegics
Authors: Quintern J. , Riener R. , Rupprecht S.
Published: December 2008

Open‐loop and closed‐loop stimulation of the knee extensors for the controlof the knee joint angle and torque were tested as a potential basis for morecomplex functional electrical stimulation (FES) systems to be used in human locomotion. The output of the biomechanical simulation model described previously was compared with stimulation experiments in patients with complete thoracic spinal cordinjury. Good correspondence between simulation and experiments was obtained under both isometric conditions and conditions with a freely swinging shank. For closed‐loop control, a simple proportional integral derivative (PID) controller yieldedsufficient performance only under isometric conditions, especially if combined with (linear) feedforward. Because ofadditional nonlinearities of musculotendon and body segmental dynamics, morecomplex strategies have to be applied to the control of unconstrained movements. To compensate for these nonlinearities, an inverse model was derived from the direct biomechanical model. This inverse model had satisfactory agreement between themeasured knee angle and the desired trajectory already under open‐loop conditions. A combination of the inverse model in the feedforward part of the control loop and a PID controller provided robust and precise control of the knee angle. Furtherimprovement may be achieved by including elements of spasticity into the simulation model and by controlling both agonistic and antagonistic muscles.
Predicted and Measured Muscle Forces after Recoveries of Differing DurationsFollowing Fatigue in Functional Electrical Stimulation
Authors: Mizrahi J. , Seelenfreund D. , Isakov E. , Susak Z.
Published: December 2008

Using 31P nuclear magnetic resonance (NMR) spectroscopy, thebioenergetics of paralyzed muscles activated by functional electricalstimulation (FES)were studied in vivo during fatigue and recovery on paraplegic subjects. Duringthe activation phase of the muscle, the muscle force was also monitored. Thephosphorus metaboliteswere found to vary systematically during fatigue and to recover slowly to theirrest state values after cessation of FES. During fatigue, a good correlationwas found between thedecaying force and each of the profiles of phosphocreatine, inorganicphosphorus, and intracellular pH. A musculotendon 5 element model was proposedfor the activated muscle topredict its force generation capacity. A fatigue recovery function, based onthe metabolic profiles, was introduced into the model. This model allowed us topredict the forceexpected to be developed as a function of the time after recovery of given timedurations. Validation experimental measurements of force were carried out andincluded recurrentfatigue tests, both in the initially un‐fatigued state and at various timesin the postfatigue stage of the muscle. Comparison of the predicted and measured forces indicatedsatisfactory agreement of the results. The developed model of muscle dynamicsshould help to design a strategy for reducing muscle fatigue under FES.
Restoration of Lateral Hand Grasp Using Natural Sensors
Authors: Haugland Morten , Lickel Andreas , Riso Ron , Adamczyk Margareth M. , Keith Michael , Jensen Inger Lauge , Haase Jens , Sinkjær Thomas
Published: December 2008

A closed‐loop control system for controlling the key grip of a C6tetraplegic patient was developed. Natural sensors served as the source of thefeedbacksignal. The neural signals from cutaneous receptors were picked up by animplanted cuff electrode placed around the radial branch of the median nerveinnervating the lateral partof the index finger. Mechanical stress applied to the skin, like pressure andslips, resulted in an increase in amplitude of the recorded neural signal. Thegoal of the study wasto determine whether the recorded neural signals were able to indicate the slipof an object during lateral grasp and whether the slip could be stopped byincreasing the graspforce through functional electrical stimulation of the thumb adductor andflexor.
Shifting Trade Patterns as a Means of Reducing Global Carbon Dioxide Emissions
Authors: Strømman Anders Hammer , Hertwich Edgar G. , Duchin Faye
Published: December 2008

This article extends and applies the world trade model with bilateral trade (WTMBT), a linear program with any number of goods, factors, and regional trade partners that determines regional production, bilateral trade patterns, and region‐specific prices on the basis of comparative advantage by minimizing factor use. The model provides a consistent analysis of the global production system, representing geographical location at a regional level, region‐specific technologies at a sector level, emissions from production, and resource constraints and costs. An illustrative analysis investigates how changes in the geographic distribution of production could contribute to reducing global carbon dioxide (CO2) emissions and at what cost. The model provides a bridge between global objectives and their determinants and consequences in specific sectors in individual regions. Multi‐objective analysis is used to construct a trade‐off curve between global factor costs and CO2 emissions. The relevance of both primal and dual solution variables is demonstrated. In particular, changes in goods prices and emissions are investigated. We conclude that the main impact of tightening carbon constraints is a substantial reduction in international trade accompanied by a shift away from regions most reliant on the combustion of coal. In addition to the analysis of the overall global trends, including the impact on prices, the implications of the global carbon constraint for one specific industry are investigated.
Phasing Out Cadmium, Lead, and Mercury
Authors: Månsson Nina , Bergbäck Bo , Sörme Louise
Published: December 2008

Large stocks of metals have accumulated in the urban technosphere (i.e., the physical environment altered by human activity). To minimize health and environmental risks, attempts were begun in the 1980s to phase out the use of cadmium (Cd), lead (Pb), and mercury (Hg). To study the effect of this attempt, we conducted substance flow analyses (SFAs) in Stockholm, Sweden, in 1995 and in 2002–2003, which allow a comparison of the results over time.

The SFAs showed a reduction in the stocks of Cd and Hg by approximately 25% to 30% between 1995 and 2002–2003. For Pb, the stock development was more uncertain. Cd and Hg inflow was substantially reduced during this period, but Pb inflow increased. Amounts of Cd and Pb in waste were still large, whereas Hg flows in waste were decreasing. Furthermore, although emissions of Pb decreased, Cd and Hg emissions were in the same range as in 1995.

The application of SFAs has provided unique data on the accumulation of metals in the Stockholm technosphere, thus serving as a valuable indicator of how the phasing out progresses. The changes can be related to regulations, initiatives by industries and organizations, and the proactive attitude of the local environmental authorities and of the water company.
A Transitional Overlay Partial Denture for a Young Patient: A Clinical Report
Authors: Zarati Simin , Ahmadian Leila , Arbabi Rasoul
Published: December 2008

This clinical report describes a noninvasive approach for the treatment of a patient diagnosed with amelogenesis imperfecta (AI) and severe anterior open bite. The patient's functional and esthetic expectations were successfully met with a transitional overlay removable partial denture.
Influence of Investment, Disinfection, and Storage on the Microhardness of Ocular Resins
Authors: Goiato Marcelo Coelho , Santos Daniela Micheline dos , Gennari‐Filho Humberto , Zavanelli Adriana Cristina , De Carvalho Dekon Stefan Fiuza , Mancuso Daniela Nardi
Published: December 2008

Purpose: The longevity of an ocular prosthesis is directly related to the resistance to erosion of its material. The purpose of this study was to evaluate the effects of chemical disinfection and the method of investment on the microhardness of ocular prosthesis acrylic resin.

Materials and Methods: Thirty‐two test specimen investments were obtained in two silicones. A segment was cut in each test specimen, and each specimen was fixed in an acrylic disk. The specimens were then polished and submitted to the first microhardness test before immersion in distilled water and incubation for 2 months. During this 2‐month period, the specimens were immersed in a water bath at 37°C and were disinfected daily; half were disinfected with neutral soap and the other half were disinfected with 4% chlorhexidine gluconate. After the storage phase and disinfection, a second microhardness test was performed. The surface microhardness values for the acrylic resins were submitted to ANOVA, followed by the Tukey test.

Results: The disinfection and the period of storage did not statistically influence the surface microhardness of the acrylic resin, independent of the method of investment of the specimens (Zetalabor or Vipi Sil). The investment of specimens with Zetalabor silicone presented a greater surface hardness, independent of the type of disinfection and the period of storage.

Conclusions: Based on these results, we suggest that the microhardness of the resin evaluated was not influenced by the method of disinfection or the time of storage used and was affected only by the investment material.
Oral Cancer: A Prosthodontic Diagnosis
Authors: Siegel Michael A. , Kahn Michael A. , Palazzolo Mitzi J.
Published: December 2008

The prosthodontic literature is replete with articles addressing the reconstruction, psychological adaption, prosthesis success, quality of life, need for careful follow‐up, and many other issues related to the patient who has undergone surgery, radiation, and/or chemotherapy for oral malignant neoplasms. However, in the prosthodontic professional literature, there is a paucity of information related to the early diagnosis and referral of lesions that may represent premalignant or malignant neoplasia. This article will describe the rationale, epidemiology, and appearance of oral premalignant and malignant mucosal lesions as well as the state‐of‐the‐art diagnostic tools currently available to prosthodontists to ensure that their patients are diagnosed at the earliest possible time.
Fracture Resistance of Endodontically Treated Teeth: Three Walls versus Four Walls of Remaining Coronal Tooth Structure
Authors: Arunpraditkul Siriporn , Saengsanon Siranee , Pakviwat Wilasinee
Published: December 2008

Purpose: The purpose of this study was to evaluate the fracture resistance of endodontically treated teeth between those with four walls and those with three walls of remaining coronal tooth structure and the effect of the site of the missing coronal wall.

Materials and Methods: Thirty‐two endodontically treated second mandibular premolars were decoronated, leaving 3 mm above the cementoenamel junction (CEJ). A 0.5‐mm‐wide chamfer was prepared 1 mm above the CEJ. The teeth were randomly divided into four groups. Group 1 had four walls of coronal tooth structure, whereas groups 2, 3, and 4 had only three walls, missing the buccal, lingual, and mesial wall, respectively. The cast dowel and cores and crowns (Ni–Cr alloy) were cemented with zinc phosphate cement. A compressive load was applied 45° to the long axis, 2 mm below the buccal cusp, with an Instron machine until failure at a crosshead speed of 5 mm/min. Failure load (kg) and mode of failure were recorded. Data were analyzed with one‐way ANOVA and Scheffé tests (p < 0.05).

Results: Group 1 had the highest fracture resistance (1190.3 ± 110.5 kg), significantly different from the other groups (p < 0.05) (group 2: 578.5 ± 197.4 kg; group 3: 786.6 ± 132.8 kg; group 4: 785.4 ± 289.9 kg). There were no significant differences among the test groups. The mode of failure in group 1 was a horizontal root fracture, whereas that of the other groups was either vertical or oblique fracture.

Conclusions: Teeth with four walls of remaining coronal dentine had significantly higher fracture resistance than teeth with only three walls. The site of the missing coronal wall did not affect the fracture resistance of endodontically treated teeth.
Fracture Resistance of Yttria‐Stabilized Zirconia Dental Implant Abutments
Authors: Adatia Nimet D. , Bayne Stephen C. , Cooper Lyndon F. , Thompson Jeffery Y.
Published: December 2008

Purpose: An in vitro study was performed to assess the effect of different degrees of clinical reduction of zirconia abutments on the failure load of clinical assemblies.

Materials and Methods: Zirconia abutments (Y‐TZP Ceramic Abutment, Astra Tech) were prepared with 0, 0.5, or 1 mm of external axial reduction starting 1 mm above the height‐of‐contour. Abutments (n = 10) were attached to implant analogs (25 Ncm torque) embedded in a stainless steel cylinder using Field's metal. Fracture loads (N) were determined when assemblies were loaded at 60° off‐axis until failure (Instron, CHS = 0.1 mm/min). Groups were statistically compared using ANOVA (p < 0.05).

Results: Fracture loads for all assemblies displayed large variations within groups. There were no statistically significant differences (p > 0.05) among different abutment groups with a mean fracture load of 429 N (±140) for the control group, 576 N (±120) for 0.5‐mm margins, and 547 (±139) for 1.0‐mm margins. All fractures occurred at the interface where the abutment was connected to the analog.

Conclusion: In this in vitro study of simulated ultimate assembly strength, the preparation of zirconia abutments did not significantly impair the fracture resistance of simulated implant assemblies. All implant abutments fractured at rates higher than the maximum incisal forces (90–370 N) estimated to occur in the anterior region of the mouth.
Grindability of Cast Ti‐6Al‐4V Alloyed with Copper
Authors: Watanabe Ikuya , Aoki Takayuki , Okabe Toru
Published: December 2008

Purpose: This study investigated the grindability of cast Ti‐6Al‐4V alloyed with copper.

Materials and Methods: The metals tested were commercially pure titanium (CP Ti), Ti‐6Al‐4V, experimental Ti‐6Al‐4V‐Cu (1, 4, and 10 wt% Cu), and Co‐Cr alloy. Each metal was cast into five blocks (3.0 × 8.0 × 30.0 mm3). The 3.0‐mm wide surface of each block was ground using a hand‐piece engine with an SiC wheel at four circumferential speeds (500, 750, 1000, and 1250 m/min) at a grinding force of 100 g. The grindability index (G‐index) was determined as volume loss (mm3) calculated from the weight loss after 1 minute of grinding and the density of each metal. The ratio of the metal volume loss and the wheel volume loss was also calculated (G‐ratio, %). Data (n = 5) were statistically analyzed using ANOVA (α= 0.05).

Results: Ti‐6Al‐4V and the experimental Ti‐6Al‐4V‐Cu alloys exhibited significantly (p < 0.05) higher G‐indexes compared with CP Ti and Co‐Cr at any rotational speed except for the lowest speed (500 m/min). At 500 m/min, the G‐index of Ti‐6Al‐4V‐Cu increased as the amount of alloyed copper increased. The 4% Cu and 10% Cu alloys had significantly greater G‐indexes than did 1% Cu and Ti‐6Al‐4V at the highest rotational speed (1250 m/min). Increasing the percentage of alloyed copper and the circumferential speed also increased the G‐ratio.

Conclusions: A slight reduction in ductility due to alloying Ti‐6Al‐4V with copper improved the grindability of some of the resultant Ti‐6Al‐4V‐Cu alloys.
Effect of Surface Preparation on the Failure Load of a Highly Filled Composite Bonded to the Polymer‐Monomer Matrix of a Fiber‐Reinforced Composite
Authors: Shimizu Hiroshi , Tsue Fumitake , Chen Zhao‐Xun , Takahashi Yutaka
Published: December 2008

Purpose: The purpose of the present study was to evaluate the effect of surface preparation on the maximum fracture load value of a highly filled composite bonded to the polymer‐monomer matrix of a fiber‐reinforced composite.

Materials and Methods: A polymer‐monomer matrix was made by mixing urethane dimethacrylate and triethyleneglycol dimethacrylate at a ratio of 1:1 with camphorquinone and 2‐dimethylaminoethyl methacrylate as a light initiator. The matrix was then polymerized in a disk‐shaped silicone mold with a light‐polymerizing unit. The flat surfaces of the polymer‐monomer matrix disk were prepared in one of the following ways: (1) without preparation; (2) application of silane coupling agent; or (3) application of matrix liquid and prepolymerization. A highly filled composite material was applied and polymerized with a light‐polymerizing unit. Additional test specimens made entirely of the polymer‐monomer matrix were fabricated as references; the disk and cylinder were fabricated in one piece using a mold specially made for the present study (group 4). Half the specimens were thermocycled up to 10,000 times in water with a 1‐minute dwell time at each temperature (5°C and 55°C). The maximum fracture load values were determined using a universal testing machine (n = 10).

Results: The maximum fracture loads for group 3 were significantly enhanced both before and after thermocycling, whereas the maximum fracture loads of group 2 were significantly enhanced before thermocycling (p < 0.05); however, the failure loads decreased for all groups after thermocycling (p < 0.05). All the specimens in groups 1 and 2 debonded during thermocycling. The failure load of group 3 was significantly lower than that of group 4 both before and after thermocycling (p < 0.05).

Conclusion: Within the limitations of the current in vitro study, the application and prepolymerization of a mixed dimethacrylate resin liquid prior to the application of a highly filled composite was an effective surface preparation for the polymer‐monomer matrix of a fiber‐reinforced composite; however, the bond durability may be insufficient.
An Alternative Procedure for Fabricating a Hollow Interim Obturator for a Partial Maxillectomy Patient
Authors: Shimizu Hiroshi , Yoshida Kaneyoshi , Mori Nobuaki , Takahashi Yutaka
Published: December 2008

A technique is described for fabricating an interim obturator for a partial maxillectomy patient. This technique enables the immediate and easy chairside fabrication of a lightweight hollow‐type interim obturator when a preoperative cast is not available. After a master cast is formed, two duplicate casts are made from the master cast. One portion of the obturator is fabricated on a duplicate cast with a corrected defect, and the other portion of the prosthetic base is made on the second duplicate cast with a corrected alveolar ridge. These two portions are connected and adjusted in the patient's oral cavity. This technique is beneficial because it helps patients maintain good esthetics and their ability to speak, swallow, and chew just after surgery.
The Maximal Covering Problem with Some Negative Weights
Authors: Berman Oded , Drezner Zvi , Wesolowsky George O.
Published: January 2009

This article presents the maximal covering problem on a network when some of the weights can be negative. Integer programming formulations are proposed and tested with ILOG CPLEX. Heuristic algorithms, an ascent algorithm, and simulated annealing are proposed and tested. The simulated annealing approach provides the best results for a data set comprising 40 problems.
Venture Capitalists as Catalysts to New Venture Internationalization: The Impact of Their Knowledge and Reputation Resources
Authors: Fernhaber Stephanie A. , McDougall-Covin Patricia P.
Published: December 2008

Venture Capitalists (VC) play an important role in influencing the strategic direction of the firms in which they invest. The findings of this study reveal that VCs can serve as a catalyst to new venture internationalization through the provision of knowledge and reputation resources. Furthermore, the international knowledge of a VC is more positively related to new venture internationalization when the VC is also reputable.
Detection of Severe Stenosis and Total Occlusion in the Left Anterior Descending Coronary Artery with Transthoracic Doppler Echocardiography in the Emergency Room
Authors: Tani Tomoko , Tanabe Kazuaki , Kitai Takeshi , Yamane Takafumi , Kureha Fumie , Katayama Minako , Tamita Koichi , Kaji Shuichiro , Oda Tomoyuki , Ehara Natsuhiko , Kinoshita Makoto , Yamamuro Atsushi , Morioka Shigefumi , Kihara Yasuki
Published: December 2008

Background: The noninvasive measurement of coronary flow velocity in the left anterior descending artery (LAD) has recently been realized by using the transthoracic Doppler echocardiography (TTDE). A couple of investigations demonstrated that the diastolic‐to‐systolic peak velocity ratio (DSVR) by TTDE is a simple and noninvasive method for the detection of severe stenosis in the elective settings. However, the usefulness of DSVR by TTDE in the emergency settings has not been evaluated. Objective: The purpose of this study was to assess the clinical feasibility to document the LAD flow by TTDE in emergency patients who complained of chest pain. Methods: We studied 49 consecutive patients with acute coronary syndrome who were going to undergo emergency coronary angiography (CAG) for the anatomical diagnosis and the facilitated percutaneous coronary intervention (PCI). Prior to CAG, we recorded the LAD flow by TTDE and measured the diastolic peak velocity (DVp), systolic peak velocity (SVp), and their ratio, DSVR (DVp/SVp) of LAD flow. Results: By CAG, the culprit lesions actually resided in the proximal LAD in 36 patients. Among the 36 patients, we detected the Doppler LAD flow in 29. Five out of 7 patients who were unable to detect the LAD flow revealed total occlusions by CAG. DSVR of the LAD is significantly lower in 17 patients who showed severe stenoses (>90%) than those in the rest of 12 patients who did not show such critical stenoses (1.44 ± 0.16 vs 2.10 ± 0.26, P < 0.0001). Conclusion: In the emergency settings, a noninvasive assessment of the LAD flow by TTDE accurately estimates the critical stenotic lesions of the LAD.
The Use of 3D Contrast‐Enhanced CT Reconstructions to Project Images of Vascular Rings and Coarctation of the Aorta
Authors: Di Sessa Thomas G. , Di Sessa Peter , Gregory Bill , Vranicar Mark
Published: December 2008

Background: Aortic arch and pulmonary artery anomalies make up a group of vascular structures that have complex three‐dimensional (3D) shapes. Tortuosity as well as hypoplasia or atresia of segments of the aortic arch or pulmonary artery makes the conventional two‐dimensional (2D) imaging difficult. Methods: Nine patients with native coarctation or recoarctation and 4 patients with a vascular ring had a CT scan as a part of their clinical evaluation. There were 7 males. The mean age was 11.7 years. (range 19 days to 29 years) The mean weight was 22.7 kg (range 3.3–139.0 kg). The dicom data from contrast CT scans were converted by the Amira software package into a 3D image. The areas of interest were selected. The images were then projected in 3D on a standard video monitor and could be rotated 360° in any dimension. Results: Adequate CT scans and 3D reconstructions were obtained in 12 of 13 patients. There were 85–1,044 slices obtained in the adequate studies. We could not reconstruct a 3D image from a patient's CT scan that had only 22 slices. The anatomy defined by 3D was compared to 2D CT imaging and confirmed by cardiac catheterization or direct visualization in the operating room in the 12 patients with adequate 3D reconstructions. In 5 of 12 patients, 3D reconstructions provided valuable spatial information not observed in the conventional 2D scans. Conclusion: We believe that 3D reconstruction of contrast‐enhanced CT scans of these complex structures provides additional valuable information that is helpful in the decision‐making process.
The Effect of Emergency Department Crowding on Clinically Oriented Outcomes
Authors: Bernstein Steven L. , Aronsky Dominik , Duseja Reena , Epstein Stephen , Handel Dan , Hwang Ula , McCarthy Melissa , John McConnell K. , Pines Jesse M. , Rathlev Niels , Schafermeyer Robert , Zwemer Frank , Schull Michael , Asplin Brent R. ,   Society for Academic Emergency Medicine, Emergency Department Crowding Task Force
Published: December 2008

Background:  An Institute of Medicine (IOM) report defines six domains of quality of care: safety, patient‐centeredness, timeliness, efficiency, effectiveness, and equity. The effect of emergency department (ED) crowding on these domains of quality has not been comprehensively evaluated.

Objectives:  The objective was to review the medical literature addressing the effects of ED crowding on clinically oriented outcomes (COOs).

Methods:  We reviewed the English‐language literature for the years 1989–2007 for case series, cohort studies, and clinical trials addressing crowding’s effects on COOs. Keywords searched included “ED crowding,”“ED overcrowding,”“mortality,”“time to treatment,”“patient satisfaction,”“quality of care,” and others.

Results:  A total of 369 articles were identified, of which 41 were kept for inclusion. Study quality was modest; most articles reflected observational work performed at a single institution. There were no randomized controlled trials. ED crowding is associated with an increased risk of in‐hospital mortality, longer times to treatment for patients with pneumonia or acute pain, and a higher probability of leaving the ED against medical advice or without being seen. Crowding is not associated with delays in reperfusion for patients with ST‐elevation myocardial infarction. Insufficient data were available to draw conclusions on crowding’s effects on patient satisfaction and other quality endpoints.

Conclusions:  A growing body of data suggests that ED crowding is associated both with objective clinical endpoints, such as mortality, as well as clinically important processes of care, such as time to treatment for patients with time‐sensitive conditions such as pneumonia. At least two domains of quality of care, safety and timeliness, are compromised by ED crowding.
VEGF is a mediator of the renoprotective effects of multipotent marrow stromal cells in acute kidney injury
Authors: Tögel Florian , Zhang Ping , Hu Zhuma , Westenfelder Christof
Published: December 2008

Adult stem cell treatment of complex disorders is a promising therapeutic approach and multipotent marrow stromal cells (MSCs) have been shown to be effective in various animal models of diseases. Acute kidney injury (AKI) is a common and serious problem in hospitalized patients and bone marrow derived multipotent MSCs have been shown to be effective in different models of AKI. The mechanism of action of MSCs is complex but involves paracrine actions including growth factor secretion. Knockdown of vascular enthothelial growth factor (VEGF) by siRNA reduced effectiveness of MSCs in the treatment of ischemic AKI in a rat model. Animals treated with MSCs had increased renal microvessel density compared to VEGF knockdown MSC‐treated and vehicle‐treated animals. These results show that VEGF is an important mediator of the early and late phase of renoprotective action after AKI in the context of stem cell treatment.
Feeding of mice with Arabidopsis thaliana expressing the HIV‐1 subtype C p24 antigen gives rise to systemic immune responses
Authors: LINDH INGRID , KALBINA IRINA , THULIN SARA , SCHERBAK NIKOLAI , SÄVENSTRAND HELENA , BRÅVE ANDREAS , HINKULA JORMA , STRID ÅKE , ANDERSSON SÖREN
Published: December 2008

Development of transgenic edible plants, to be used as production, storage and delivery systems for recombinant vaccine antigens, is a promising strategy to obtain cost effective vaccines against infectious diseases, not least for use in developing countries. Therefore, we used Agrobacterium tumefaciens‐mediated gene transfer to introduce the p24 gag gene encoding the nucleocapsid protein from HIV‐1 subtype C into the Arabidopsis thaliana plant genome. Eighteen plant lines were confirmed positive for the p24 gene by PCR; four of these lines showed an apparent homozygous phenotype when grown on selective medium and these lines also showed transcription of the p24 gene into its corresponding mRNA. The mRNA in all four cases generated the p24 protein in plants, as verified by Western blot analysis. The plants were shown to contain between 0.2 μg and 0.5 μg p24 protein per g of fresh tissue. Analysis of the localisation of the p24 protein showed that stem tissue contained the largest amount of protein, more than twice as much as leaf tissue, whereas no p24 protein was detected in roots. By using Southern blotting, we found that 4, 2–3, 2 and 1 T‐DNA insertion events took place in the four lines 1, 2, 7, and 10, respectively. The genetic insertions of line 1 were stable from the T2 to the T5 generation and gave rise to the p24 protein in all cases, as verified by Western blotting. In mice fed with fresh transgenic A. thaliana (line 10), anti‐gag IgG was obtained in serum after a booster injection with recombinant p37Gag. No immune response was observed after equal booster injection of untreated mice or mice fed with A. thaliana WT plants.
Expression of caspase‐3‐dependent apoptosis in mural thrombi leukocytes
Authors: CHU PAO‐HSIEN , JUNG SHIH‐MING , YEH CHI‐HSIAO , WU HSUEH‐HUA , SHIU TZU‐FANG , SHE HUNG‐CHUNG , TSENG NGAN‐MING
Published: December 2008

Failure of arteriovenous access is mostly due to graft thrombosis and multifactorial, with medical and surgical etiologies. Apoptosis of blood cells, such as macrophages, lymphocytes and eosinophils, may play an important role in thrombus formation. We also investigated caspase‐3‐dependent apoptosis in thrombi. We recorded clinical parameters in 43 consecutive patients with vascular access failure (13 men, 30 women; mean age±SD, 64.6±14.2 years) who underwent surgical thrombectomy. Major presentations included absent (92%) and/or near near‐absent (16%) flow through the access during hemodialysis. Cardiovascular risk factors were hypertension (70%), hyperlipidemia (47%), diabetes mellitus (47%), chronic obstructive pulmonary disease (12%), heart failure (12%), coronary artery disease (21%), and stroke (16%). Laboratory data included hemoglobin level of 100±17 g/L, total white blood cell count of 7.65±2.14×109/L, and platelet count of 205.6±57.9 1000/ìL. Abnormal biochemistry data included elevated blood urea nitrogen level of 63.5±24.4 mg/dL and creatinine level of 8.6±4.0 mg/dL (normal <1.4 mg/dL). Thrombi were characterized by apoptosis (32%) in a caspase‐dependent pathway in all types of leukocytes. Thrombi in arteriovenous access failure demonstrate apoptosis by means of the caspase‐3 pathway in white blood cells.
Choice of endothelial marker is crucial for assessment of bone marrow microvessel density in chronic lymphocytic leukemia
Authors: SMOLEJ L. , KAŠPAROVÁ P.
Published: December 2008

Angiogenesis is a potential prognostic factor in chronic lymphocytic leukemia (CLL). Elevated circulating levels of angiogenic factors in CLL have been repeatedly reported. Nevertheless, the issue of bone marrow neovascularization in CLL remains controversial, partly due to limited number of published studies, different methods of assessing microvessel density (MVD) and small patient cohorts. Moreover, there are very scarce data regarding the relationship of marrow angiogenesis to prognostic markers in CLL. Our objectives were: 1. To assess bone marrow MVD in CLL using two different monoclonal antibodies and a reproducible method of MVD quantification; 2. To examine the possible association of marrow MVD and clinical course, pattern of marrow infiltration, Rai stage, cytogenetic abnormalities detected by fluorescence in situ hybridization (FISH), and mutation status of immunoglobulin heavy chain variable region (IgVH). MVD was higher using CD34 vs vWF antibody (p<0.0001). However, no MVD differences were detected between CLL subgroups subdivided according to the above‐mentioned prognostic factors. In conclusion, MVD assessment using anti‐CD34 resulted in higher MVD counts than when using anti‐vWF antibody. No association of MVD with any prognostic factors was observed, possibly due to the limited patient cohort. As the need for bone marrow trephine biopsies in CLL is significantly decreasing, a standardized method of neovascularization assessment is required to enable possible multicentre studies in order to conduct larger investigations and thereby shed more light on the real clinical significance of bone marrow angiogenesis in CLL.
Solitary fibrous tumour of the kidney with sarcomatous overgrowth . Case report and review of the literature
Authors: MAGRO GAETANO , EMMANUELE CARMELA , LOPES MARIA , VALLONE GIUSEPPE , GRECO PAOLO
Published: December 2008

Solitary fibrous tumour (SFT) rarely occurs in the kidney, with only one case exhibiting malignant behaviour. We report the case of a typical SFT of the kidney with sarcomatous overgrowth in a 34‐year‐old woman. This malignant component, grossly apparent as a nodular area arising in the context of the main tumour mass, consisted of CD34+ mitotically active atypical plump spindle‐ to epithelioid‐shaped cells, including pleomorphic multinucleated giant cells. A novel immunohistochemical finding was diffuse and strong S‐100 protein expression by sarcomatous cells. This should be kept in mind by pathologists to avoid confusion with other S‐100 protein‐positive malignant neoplasms.
Staphylococcus aureus as source of catheter‐related bloodstream infection evaluated by PFGE and rep‐PCR typing in a Brazilian hospital
Authors: SADOYAMA GERALDO , SANTOS KÁTIA REGINA NETTO DOS , BRILHANTE ANIKE PEREIRA , FILHO PAULO PINTO GONTIJO
Published: December 2008

Staphylococci are a common cause of catheter‐related bloodstream infection (CR‐BSI), and epidemiological typing is an important tool for effective infection control. This study evaluated by PFGE and rep‐PCR whether Staphylococcus aureus strains isolated from skin and catheter tips were related to specimens isolated from blood. A prospective observational study, carried out in a clinical surgical ward at a Brazilian hospital between September 2000 and November 2002, investigated non‐tunneled central venous catheters from 179 patients. S. aureus isolates were mainly obtained from blood (41.4%), while coagulase‐negative staphylococci strains were more often isolated from the skin at the catheter insertion site (49.7%) and from the catheter tip (57.5%). Among the 21 strains isolated from 9 patients at 2 or 3 sites simultaneously, 9 were methicillin‐resistant S. aureus (MRSA) and 12 were methicillin‐susceptible S. aureus (MSSA). Seven patients harbored the same S. aureus strain isolated from the skin, blood and/or catheter tip cultures. MRSA isolates belonged to one PFGE pattern (type A‐ subtypes A1, A2 and A3), and to two rep‐PCR patterns (a and b). MSSA isolates were distinguished in five PFGE (B to F) and in three rep‐PCR (c, d and e) patterns. Both PFGE and rep‐PCR methods indicated that the skin at the catheter insertion site was the origin of CR‐BSI caused by S. aureus.
Effect of interferon gamma and CD40 ligation on intracellular monocyte survival of nontypeable Haemophilus influenzae
Authors: KING PAUL , NGUI JAMES , OPPEDISANO FRANCES , ROBINS‐BROWNE ROY , HOLMES PETER , HOLDSWORTH STEPHEN
Published: December 2008

Nontypeable Haemophilus influenzae (NTHi) is a mucosal pathogen that is a major cause of respiratory infection, including sinusitis, otitis media and bronchitis. This bacterium has evolved a number of mechanisms to facilitate its survival in the human host. Recently it has been recognized that it is capable of intracellular survival in monocytes/macrophages and epithelial cells. Previous work by the authors has demonstrated that the protective response to NTHi is Th1 predominant. This information led to the hypothesis that the intracellular survival of NTHi in human monocytes may be reduced by two key effector mechanisms of Th1‐mediated immunity: interferon gamma and ligation of CD40. This study assessed the effect of interferon gamma and ligation of CD40 on the intracellular survival of NTHi in human monocytes. Responses were studied in monocytes from subjects with bronchiectasis and persistent airway infection with NTHi and compared with control subjects. The results demonstrated that different isolates of NTHi were able to survive inside monocytes. Killing of one strain of NTHi could be enhanced by the addition of interferon gamma and CD40 ligation in both control and bronchiectasis subjects. Other strains were more resistant.
Recurrence of pleomorphic adenoma of the parotid gland—predictive value of cadherin‐11 and fascin
Authors: BRIEGER JUERGEN , DUESTERHOEFT ANNE , BROCHHAUSEN CHRISTOPH , GOSEPATH JAN , KIRKPATRICK C. JAMES , MANN WOLF J.
Published: December 2008

The predictive value of cadherin‐11, tenascin, fascin, and mucin‐1 as markers for the likelihood of recurrence in pleomorphic adenoma of the parotid gland was examined. In this retrospective study we analysed 20 tumours from16 patients by immunohistochemistry. Staining intensities were measured using a semiquantitative scoring approach; localisation (tumour centre vs border) as well as clinical data were analysed and correlated with follow‐up. Cadherin‐11 was increased in recurrent tumours. However, no changes of fascin, tenascin or mucin‐1 were observed. Cadherin‐11 and fascin were increased in primary tumours of patients with later recurrence, with fascin upregulation restricted to the tumour border. In conclusion, cadherin‐11 and fascin should be further analysed for their value as markers for later recurrence in pleomorphic adenoma. Our observations might reflect dysregulation of cellular pathways contributing to cellular dissemination, which might potentially result in later recurrence.
Cutaneous involvement in the lymphoepithelioid variant of peripheral T‐cell lymphoma, unspecified (Lennert lymphoma). Report of a case and review of the literature
Authors: Summers Thomas A. , Rush Walter , Aguilera Nadine , Lupton George
Published: December 2008

Lennert lymphoma (LL), or the lymphoepithelioid variant of peripheral T‐cell lymphoma, is an uncommon entity with rarely seen or reported presentations in the skin. Cutaneous involvement of LL has been characterized by asymptomatic, non‐ulcerated, red to violet papules, nodules and small plaques (less than 5 cm) on the trunk and extremities. Histologically, there are localized cellular lymphoid infiltrates in the dermis that tend to localize around blood vessels or skin appendages. Key to the diagnosis of LL is the presence of epithelioid histiocytes and atypical small lymphoid cells without increased vascularity or epidermotropism. Immunophenotyping shows a dense monoclonal T‐cell population commonly associated with aberrant loss of T‐cell‐associated antigens. T‐cell receptor gene rearrangements are also identified. Patients typically present with advanced stage and have a low 5‐year survival. Herein, we present a case of cutaneous involvement by LL at the time of initial presentation that persisted after initiation of chemotherapy and was finally verified as secondary cutaneous involvement of LL 1 year later histologically, immunophenotypically and by T‐cell receptor gene rearrangement studies.
Liver receptor homolog‐1 localization in the nuclear body is regulated by sumoylation and cAMP signaling in rat granulosa cells
Authors: Yang Feng‐Ming , Pan Chien‐Ting , Tsai Huei‐Man , Chiu Tai‐Wei , Wu Mei‐Ling , Hu Meng‐Chun
Published: December 2008

Liver receptor homolog‐1 (LRH‐1; NR5A2) is an orphan member of the nuclear receptor superfamily, mainly expressed in endoderm‐derived tissues and in the ovary. In ovarian granulosa and luteal cells, LRH‐1 regulates the expression of genes associated with ovarian steroidogenesis. LRH‐1 can be transported to transcriptionally inactive nuclear bodies after conjugation with small ubiquitin‐related modifier (SUMO). In the present study, we investigated the effects of SUMO modification at five lysine residues of LRH‐1 in rat granulosa cells. Lysine 289 could be conjugated with SUMO‐1 in vitro, and the mutation K289R increased transcriptional activity of LRH‐1, suggesting that SUMO conjugation is associated with transcription repression. Coexpression of SUMO‐1 targets LRH‐1 to the dot‐like nuclear bodies, but the effect of lysine mutations on blocking subnuclear localization depended on the cell type. In COS‐7 cells, mutation of either K173 or K289 prevented SUMO‐1‐mediated translocation of LRH‐1 into nuclear bodies and also reduced the conjugation by SUMO‐1, suggesting that K289 and K173 are two important sites involved in SUMO‐1 modification. In granulosa cells, three or more altered lysine residues were required for nucleoplasm retention. This result suggests that multiple lysine residues are targets for SUMO conjugation in vivo and granulosa cells are more sensitive to SUMO‐1‐mediated LRH‐1 localization to nuclear bodies. Nuclear body localization of LRH‐1 was suppressed by forskolin and cholera toxin. Forskolin treatment obviously influences the expression of members involved in the SUMO pathway. The results obtained in the present study suggest that cAMP signaling could change the dynamic process of sumoylation and repress LRH‐1 targeting to nuclear speckles in rat granulosa cells.