bluuebunny/crossref_metadata_2025 huggingface dataset:
Aligned Er-Doped ZnO Nanorod Arrays with Enhanced 1.54 μm Infrared Emission
Authors: Yang W. C. , Wang C. W. , Wang J. C. , Chang Y. C. , Hsu H. C. , Nee Tzer-En , Chen L. J. , He J. H.
Published: July 2008

Vertically aligned Er-doped ZnO nanorod arrays with sharp and intense 1.54 μm infrared emission have been fabricated on Si substrates through a well controlled spin-coating and annealing process. The synthesis method is advantageous for synthesizing ZnO nanostructures free
from structural defects, capability for large-scale production, minimum equipment requirement and product homogeneity. Er atoms were found to incorporate into ZnO lattice from XRD, ESCA, TEM, STEM/EDS and PL measurements. The single-crystal Er-doped nanorods maintained their high microstructural
quality after annealing for 4 hr at 800 °C. The intensity of 1.54 μm infrared emission was found to be correlated with the deep level green emission. The enhanced luminescence intensity and best ever narrow wavelength distribution of Er-doped ZnO nanorod arrays at 1.54 μm
emission will be conductive to applications in optoelectronic devices and optical communications.
On Estimating Dry Deposition Rates in Complex Terrain
Authors: Hicks Bruce B.
Published: July 2008

In complex terrain, horizontal advection and filtration through a canopy can add substantially to the vertical diffusion component assumed to be the dominant transfer mechanism in conventional deposition velocity formulations. To illustrate this, three separate kinds of terrain complexity are addressed here: 1) a horizontal landscape with patches of forest, 2) a uniformly vegetated gentle hill, and 3) a mountainous area. In flat areas with plots of trees, the elevation of the standard area-weighted dry deposition velocity will likely depend on the product hn1/2, where h is the tree height and n is the number of plots per unit area. For the second case, it is proposed that the standard “flat earth” deposition velocity might need to be increased by a factor like [1 + Ra/(Rb + Rc)]1/2. For mountainous ecosystems, where no precise estimate of local dry deposition appears attainable, the actual dry deposition rate is probably bounded by the extremes associated with 1) the flat earth assumption involving aerodynamic, quasi-boundary layer, and canopy resistances as in conventional formulations, and 2) an alternative assumption that the aerodynamic resistance is zero. Such issues are of particular importance in the context of atmospheric loadings to sensitive ecosystems, where the concepts of critical loads and deposition forecasting are now of increasing relevance. They are probably of less importance if the emphasis is on air quality alone, because air quality responds slowly to changes in deposition rates. The issues addressed here are mainly appropriate in the context of air surface exchange that is not controlled by surface resistance (e.g., for deposition of easily captured chemicals such as nitric acid vapor, and perhaps for atmospheric momentum) and for chemicals that have no local sources. It is argued that dry deposition rates derived from classical applications of deposition velocities are often underestimates.
Dewpoint Temperature Prediction Using Artificial Neural Networks
Authors: Shank D. B. , Hoogenboom G. , McClendon R. W.
Published: July 2008

Dewpoint temperature, the temperature at which water vapor in the air will condense into liquid, can be useful in estimating frost, fog, snow, dew, evapotranspiration, and other meteorological variables. The goal of this study was to use artificial neural networks (ANNs) to predict dewpoint temperature from 1 to 12 h ahead using prior weather data as inputs. This study explores using three-layer backpropagation ANNs and weather data combined for three years from 20 locations in Georgia, United States, to develop general models for dewpoint temperature prediction anywhere within Georgia. Specific objectives included the selection of the important weather-related inputs, the setting of ANN parameters, and the selection of the duration of prior input data. An iterative search found that, in addition to dewpoint temperature, important weather-related ANN inputs included relative humidity, solar radiation, air temperature, wind speed, and vapor pressure. Experiments also showed that the best models included 60 nodes in the ANN hidden layer, a ±0.15 initial range for the ANN weights, a 0.35 ANN learning rate, and a duration of prior weather-related data used as inputs ranging from 6 to 30 h based on the lead time. The evaluation of the final models with weather data from 20 separate locations and for a different year showed that the 1-, 4-, 8-, and 12-h predictions had mean absolute errors (MAEs) of 0.550°, 1.234°, 1.799°, and 2.280°C, respectively. These final models predicted dewpoint temperature adequately using previously unseen weather data, including difficult freeze and heat stress extremes. These predictions are useful for decisions in agriculture because dewpoint temperature along with air temperature affects the intensity of freezes and heat waves, which can damage crops, equipment, and structures and can cause injury or death to animals and humans.
A Two-Tier Statistical Forecast Method for Agricultural and Resource Management Simulations
Authors: Mauget Steven A. , Ko Jonghan
Published: July 2008

Simple phase schemes to predict seasonal climate based on leading ENSO indicators can be used to estimate the value of forecast information in agriculture and watershed management, but may be limited in predictive skill. Here, a simple two-tier statistical method is used to hindcast seasonal precipitation over the continental United States, and the resulting skill is compared with that of ENSO phase systems based on Niño-3 sea surface temperature anomaly (SSTA) and Southern Oscillation index (SOI) persistence. The two-tier approach first predicts Niño-3 winter season SSTA, and then converts those predictions to categorical precipitation hindcasts via a simple phase translation process. The hindcasting problem used to make these comparisons is relevant to winter wheat production over the central United States. Thus, given the state of seasonal SOI and Niño-3 indicators defined before August, the goal is to predict the tercile category of the following November–March precipitation. Generally, it was found that the methods based on either predicted or persisted winter Niño-3 conditions were skillful over areas where ENSO affects U.S. winter precipitation—that is, the Southeast and the Gulf Coast, Texas, the southern and central plains, the Southwest, Northwest, and the Ohio River valley—and that the two-tier approach based on predicted Niño-3 conditions was more likely to provide the best skill. Skill based on SOI persistence was generally lower over many of those regions and was insignificant over broad parts of the central and southwest United States, but did lead the other methods over the Ohio River valley and the northwest. A more restrictive test of leading hindcast skill showed that the skill advantages of the two-tier approach over the central and western United States were not substantial, and mainly highlighted SOI persistence’s lack of skill over the central United States and leading skill over the Ohio River valley. However, two-tier hindcasts based on neural-network-predicted Niño-3 SSTA were clearly more skillful than both ENSO phase methods over areas of the Southeast. It is suggested that the relative skill advantage of the two-tier approach may be due in part to the use of arbitrary thresholds in ENSO phase systems.
Infrared Continental Surface Emissivity Spectra Retrieved from AIRS Hyperspectral Sensor
Authors: Péquignot E. , Chédin A. , Scott N. A.
Published: July 2008

Atmospheric Infrared Sounder (AIRS; NASA Aqua platform) observations over land are interpreted in terms of monthly mean surface emissivity spectra at a resolution of 0.05 μm and skin temperature. For each AIRS observation, an estimation of the atmospheric temperature and water vapor profiles is first obtained through a proximity recognition within the thermodynamic initial guess retrieval (TIGR) climatological library of about 2300 representative clear-sky atmospheric situations. With this a priori information, all terms of the radiative transfer equation are calculated by using the Automatized Atmospheric Absorption Atlas (4A) line-by-line radiative transfer model. Then, surface temperature is evaluated by using a single AIRS channel (centered at 12.183 μm) chosen for its almost constant emissivity with respect to soil type. Emissivity is then calculated for a set of 40 atmospheric windows (transmittance greater than 0.5) distributed over the AIRS spectrum. The overall infrared emissivity spectrum at 0.05-μm resolution is finally derived from a combination of high-spectral-resolution laboratory measurements of various materials carefully selected within the Moderate-Resolution Imaging Spectroradiometer/University of California, Santa Barbara (MODIS/UCSB) and Advanced Spaceborne Thermal Emission and Reflection Radiometer/Jet Propulsion Laboratory (ASTER/JPL) emissivity libraries. It is shown from simulations that the accuracy of the method developed in this paper, the multispectral method (MSM), varies from about 3% around 4 μm to considerably less than 1% in the 10–12-μm spectral window. Three years of AIRS observations (from April 2003 to March 2006) between 30°S and 30°N have been processed and interpreted in terms of monthly mean surface skin temperature and emissivity spectra from 3.7 to 14.0 μm at a spatial resolution of 1° × 1°. AIRS retrievals are compared with the MODIS (also flying aboard the NASA/Aqua platform) monthly mean L3 products and with the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies baseline-fit method (UW/CIMSS BF) global infrared land surface emissivity database.
A Modification to the NOAH LSM to Simulate Heat Mitigation Strategies in the New York City Metropolitan Area
Authors: Lynn Barry H. , Carlson Toby N. , Rosenzweig Cynthia , Goldberg Richard , Druyan Leonard , Cox Jennifer , Gaffin Stuart , Parshall Lily , Civerolo Kevin
Published: July 2008

A new approach to simulating the urban environment with a mesocale model has been developed to identify efficient strategies for mitigating increases in surface air temperatures associated with the urban heat island (UHI). A key step in this process is to define a “global” roughness for the cityscape and to use this roughness to diagnose 10-m temperature, moisture, and winds within an atmospheric model. This information is used to calculate local exchange coefficients for different city surface types (each with their own “local roughness” lengths); each surface’s energy balances, including surface air temperatures, humidity, and wind, are then readily obtained. The model was run for several summer days in 2001 for the New York City five-county area. The most effective strategy to reduce the surface radiometric and 2-m surface air temperatures was to increase the albedo of the city (impervious) surfaces. However, this caused increased thermal stress at street level, especially noontime thermal stress. As an alternative, the planting of trees reduced the UHI’s adverse effects of high temperatures and also reduced noontime thermal stress on city residents (and would also have reduced cooling energy requirements of small structures). Taking these results together, the analysis suggests that the best mitigation strategy is planting trees at street level and increasing the reflectivity of roofs.
Face-to-Face Interaction Compared with Video Watching on Use of Physical Activity in Peripheral Arterial Disease: A Pilot Trial
Authors: Collins Tracie C. , Krueger Patricia N. , Kroll Tony L. , Sharf Barbara F.
Published: June 2008

Few studies have defined the association of physician-patient communication with physical activity levels in patients with peripheral arterial disease. We hypothesized that a face-to-face intervention versus video watching would improve physical activity levels in patients with peripheral arterial disease. The authors conducted a randomized trial involving 2 interventions. The face-to-face intervention included a brief dialogue with patients to understand their perceptions of peripheral arterial disease and importance of walking. The comparison group watched a video that included an overview of peripheral arterial disease. The primary outcome was changed from baseline to follow-up in levels of physical activity. Fiftyone patients with peripheral arterial disease were randomized. There were no statistically significant differences between the 2 groups in reported activity level or walking ability at 12 weeks. For within group changes, the patients in the video-watching group improved their walking speed (8.5%; SD = 4.1; P = .05). Patients with peripheral arterial disease may benefit from the use of an educational video to increase the use of unsupervised physical activity. Further research is needed to identify interventions that can increase the use of unsupervised physical activity in this population.
Serum Selenium and Glutathione Peroxidase Concentrations in Iranian Patients with Angiography-Defined Coronary Artery Disease
Authors: Seyyed Mohammad Reza Parizadeh , Moohebati Mohsen , Ghafoori Fahimeh , Ghayour-Mobarhan Majid , Kazemi-Bajestani Seyyed Mohammad Reza , Tavallaie Shima , Azimi-Nezhad Mohsen , Ferns Gordon A.
Published: June 2008

This study investigated the relationship between serum selenium (Se) and glutathione peroxidase (GPx) levels and the presence of coronary artery disease (CAD) among Iranian patients. Three groups were compared: patients undergoing angiography with angiographically defined CAD, individuals with a normal angiogram, and apparently healthy controls with no evidence of overt CAD. Anthropometric measurements, blood pressure, fasting blood glucose and lipid profiles, serum Se and GPx measurements, and angiographic assessment were carried out using standard protocols. Mean serum Se concentrations were not significantly different between patients with and without CAD and the control group. The mean value of serum GPx in the control group was significantly higher than in patients with or without CAD. Selenium status did not differentiate between patients with and without CAD, which may be related to the fact that angiography is not a very sensitive index of global atherosclerosis, and it is possible that patients who were CAD negative by angiogram still have significant disease. It may also be that Se is not a good marker of CAD.
Measuring and Evaluating School Performance
Authors: Zvoch Keith , Stevens Joseph J.
Published: July 2008

Several school performance indices were evaluated using achievement data from multiple longitudinally matched middle school student cohorts in a large district in the southwestern United States. Measures designed to index the within-cohort achievement status and growth of students as well as the status and growth-based changes that occur over years between different student cohorts were studied. Within- and between-cohort status and growth-based estimates of school performance were generated by applying simple and relatively complex statistical models to the longitudinal time-series data obtained on students. Results indicated that within-cohort status-based estimates were closely related to student demographics and between-cohort estimates were associated with cohort enrollment size and initial performance level. These results suggest that schools may often be rewarded and penalized on the basis of factors over which school personnel have limited or no control. Implications for the measurement and evaluation of school performance are discussed.
Temperature and Moisture Effects in a Particulate Interlayered Composite: Mode I Data Reduction and Toughness
Authors: Davidson B.D. , Soffa M.A. , Kumar M.
Published: June 2008

A study was conducted to determine the mode I toughness of T800H/3900-2 graphite/ epoxy under a range of environments that are typical of aircraft and spacecraft operating conditions. Double cantilever beam tests were performed on both dry and moisture-saturated specimens at temperatures of -43, 21, and 98°C, and on dry specimens only at 125°C. Under certain conditions, nonlinear behavior and permanent deformations were observed. Thus, a sub-study was performed to choose a data reduction method that could be used to accurately obtain the mode I toughness under all test conditions, from which a ‘load based compliance calibration method’ was selected. At a given moisture content, it was found that toughness increased with increasing temperature. Except for precracked specimens at -43°C, toughness was also found to increase with increasing moisture content. However, dramatically different behaviors were evidenced by the resistance curves from the various conditions. Aided by scanning electron microscopy, these results are explained by the mechanisms associated with crack advance, including the amount of plasticization of the matrix, matrix viscoelasticity, and the path of the growing delamination.
Becoming Writing, Becoming Writers
Authors: Colyar Julia
Published: June 2008

Many qualitative researchers have puzzled over the question of how to write more engaging, more communicative texts. “Why” we write, however, is not often part of our scholarly conversations. In this article, I examine the writing process and position writing as a learning tool which enables what researchers know about themselves and their topics. I engage with writing as a product, process, form of invention, and instrument of self-reflection. Ultimately, I suggest that writing should be included more intentionally in our research methods courses. Writing is not simply what we “do,” but also how we become better writers and scholars.
Issues in Interviewing Inmates
Authors: Schlosser Jennifer A.
Published: June 2008

Based on research the author conducted in 2006 at a men's medium-security correctional facility and on the author's experiences during that research, this article provides some insight into the issues associated with interviewing inmates. Included are discussions of gaining access to prison, negotiating Institutional Review Boards, the construction of study concepts and instruments, inmate identity, and institutional influence. Emphasizing narrative and interactionist approaches, the author's goal is to help researchers understand their role in the interview process and the author introduces an organizational interview tool called “identity moments,” wherein researchers can facilitate the retrospective and interpretative practice of building meaning through narrative. The purpose of the author's work is to provide some critical insights into conducting prison research so that future researchers might have a head start.
Dreaming in Technicolor
Authors: Raboy Marc
Published: July 2008

In the new media environment, the public broadcaster's primary purpose should be to operate at the cutting edge; it must make itself indispensable to anyone who wants to be informed, educated and entertained. And as we move towards a post-broadcasting environment, it must think of itself as a full-service public communicator.
From the Beginning
Authors: Sharkey Siobhan , Sharples Anne
Published: July 2008

This article focuses on negotiation and discusses its relevance for evaluators. Given the impetus for participatory evaluation, evaluators would benefit from improving skills that enable them to make collaborative decisions and work alongside stakeholders, in particular in community evaluations. Negotiation skills are explored through post hoc reflection of a Sure Start programme evaluation in a UK setting. Literature on stakeholder involvement and negotiation is discussed together with the UK evaluation. Recommendations are made on how to utilize elements of negotiation in community programme evaluation. Key skills are highlighted, including attention to: working with emotional situations, face-giving, rapport and creativity, timing, perceptions and improvisation.
Modelling Service User Participation in Social Care
Authors: Webb Stephen A.
Published: July 2008

• Summary: This article develops a means of evaluating service user participation in social care by modelling from a social network analysis framework.

• Findings: The three sections of the article cover: i) an overview of the literature identifying the main agendas and influences of practical and theoretical models; ii) mapping the meanings and the mechanisms of interpretation of participation in social care; iii) a positive proposal of a network analytic model for evaluating the degrees of participation in social care agencies for monitoring and evaluation. The conclusion raises some criticisms of the ways social care research has engaged in too general discussions of participation such that they cannot be operationalized. Some observations about the politics of `representation' and `faith' in calls for participation are also raised.

• Applications : A positive proposal of a network analytic model for evaluating the degrees of service user participation in social care agencies for monitoring and accountability is developed. The value of social network analysis is outlined by its emphasis on relationships between actors, as distinct from an emphasis on the attributes of individual and groups of actors. To this end a new model of participation for social care derived from network analysis is developed.
Role of IGF-1/IGF-1R in regulation of invasion in DU145 prostate cancer cells
Authors: Saikali Zeina , Setya Hemani , Singh Gurmit , Persad Sujata
Published: July 2008

Background

Prostate cancer progression to androgen independence is the primary cause of mortality by this tumor type. The IGF-1/IGF-1R axis is well known to contribute to prostate cancer initiation, but its contribution to invasiveness and the downstream signalling mechanisms that are involved are unclear at present.

Results

We examined the invasive response of androgen independent DU145 prostate carcinoma cells to IGF-1 stimulation using Matrigel assays. We then examined the signaling mechanisms and protease activities that are associated with this response. IGF-1 significantly increased the invasive capacity of DU145 cells in vitro, and this increase was inhibited by blocking IGF-1R. We further demonstrated that specific inhibitors of the MAPK and PI3-K pathways decrease IGF-1-mediated invasion. To determine potential molecular mechanisms for this change in invasive capacity, we examined changes in expression and activity of matrix metalloproteinases. We observed that IGF-1 increases the enzymatic activity of MMP-2 and MMP-9 in DU145 cells. These changes in activity are due to differences in expression in the case of MMP-9 but not in the case of MMP-2. This observation is corroborated by the fact that correlated changes of expression in a regulator of MMP-2, TIMP-2, were also seen.

Conclusion

This work identifies a specific effect of IGF-1 on the invasive capacity of DU145 prostate cancer cells, and furthermore delineates mechanisms that contribute to this effect.
Evidence for PI-3K-dependent migration of Th17-polarized cells in response to CCR2 and CCR6 agonists
Authors: Webb Adam , Johnson Andrew , Fortunato Mara , Platt Adam , Crabbe Tom , Christie Mark I , Watt Gillian F , Ward Stephen G , Jopling Louise A
Published: June 2008

IL-17-producing Th cells (Th17) are a distinct subset of effector cells that bridge the innate and adaptive immune system and are implicated in autoimmune disease processes. CD4+ splenocytes from DO11.10 mice were activated with OVA peptide323–339 and maintained under Th17 polarization conditions, resulting in significantly higher proportions of IL-17+ T cells compared with nonpolarized (Th0) cells. Th17-polarizing conditions significantly increased the proportion of cells expressing the chemokine receptors CCR2, CCR6, and CCR9 when compared with Th0 cells. In contrast, there was a significant decrease in the proportion of cells expressing CXCR3 under Th17-polarizing conditions compared with nonpolarizing conditions. The respective chemokine agonists for CCR2 (CCL2 and CCL12), CCR6 (CCL20), and CCR9 (CCL25) elicited migration and PI-3K-dependent signaling events in Th17-polarized cells, thus indicating that all three receptors were functionally and biochemically responsive. Furthermore, postmigration phenotypic analysis demonstrated that the agonists for CCR2 and CCR6, but not CCR9, stimulated a modest enrichment of IL-17+ cells compared with the premigration population. Pan-isoform inhibitors of PI-3K/Akt signaling prevented CCR2- and CCR6-mediated, polarized Th17 cell migration in a concentration-dependent manner. The unique chemokine receptor expression pattern of Th17 cells and their corresponding PI-3K-dependent migratory responses are important for understanding the pathogenesis of autoimmune diseases and may provide opportunities for the application of CCR2 and CCR6 antagonists and PI-3K isoform-selective inhibitors in defined inflammatory settings.
Complex sexual courtship displays by luminescent male marine ostracods
Authors: Rivers Trevor J. , Morin James G.
Published: June 2008

In the western Caribbean Sea, about an hour after the sun sets, a complex and ritualized light show of precise, vertically placed luminescent pulses erupts over shallow grassbeds. These are among the most complex displays known in marine systems. Displays consist of repeated trains of secreted bioluminescent pulses in a specific pattern ejected into the water column as courtship signals by male Vargula annecohenae, which are small (<2 mm) myodocopid ostracod crustaceans. Although these animals display in near darkness, we have used image intensification and infrared videography and three-dimensional analysis in the lab to demonstrate that each luminescent display train, which can be up to 60 cm long, consists of two distinct luminescent and swimming phases. The first, or `stationary,' phase consists of three (usually) bright, longer pulses placed close together, with the male swimming in a looping pattern. We hypothesize that this pattern acts as an attention-grabbing signal for receptive females. The stationary phase is followed by the `helical phase,' which consists of about a dozen evenly placed dimmer, shorter pulses secreted by an individual male rapidly spiraling upward in a helical pattern. We hypothesize that this phase, which has very uniform interpulse intervals and distances, helps an approaching female target and intercept the rapidly moving male. Here we provide details of these two phases, and produce a three-dimensional model of a multiply-displaying male.
Oxygen dependency of hydrogen sulfide-mediated vasoconstriction in cyclostome aortas
Authors: Olson Kenneth R. , Forgan Leonard G. , Dombkowski Ryan A. , Forster Malcolm E.
Published: June 2008

Hydrogen sulfide (H2S) has been proposed to mediate hypoxic vasoconstriction (HVC), however, other studies suggest the vasoconstrictory effect indirectly results from an oxidation product of H2S. Here we examined the relationship between H2S and O2 in isolated hagfish and lamprey vessels that exhibit profound hypoxic vasoconstriction. In myographic studies, H2S (Na2S) dose-dependently constricted dorsal aortas (DA) and efferent branchial arteries (EBA) but did not affect ventral aortas or afferent branchial arteries; effects similar to those produced by hypoxia. Sensitivity of H2S-mediated contraction in hagfish and lamprey DA was enhanced by hypoxia. HVC in hagfish DA was enhanced by the H2S precursor cysteine and inhibited by amino-oxyacetate, an inhibitor of the H2S-synthesizing enzyme,cystathionine β-synthase. HVC was unaffected by propargyl glycine, an inhibitor of cystathionine λ-lyase. Oxygen consumption(ṀO2) of hagfish DA was constant between 15 and 115 mmHg PO2 (1 mmHg=0.133 kPa), decreased when PO2 <15 mmHg, and increased after PO2 exceeded 115 mmHg. 10 μmol l–1 H2S increased and ⩾100μmol l–1 H2S decreased ṀO2. Consistent with the effects on HVC, cysteine increased and amino-oxyacetate decreased ṀO2. These results show that H2S is a monophasic vasoconstrictor of specific cyclostome vessels and because hagfish lack vascular NO, and vascular sensitivity to H2S was enhanced at low PO2, it is unlikely that H2S contractions are mediated by either H2S–NO interaction or an oxidation product of H2S. These experiments also provide additional support for the hypothesis that the metabolism of H2S is involved in oxygen sensing/signal transduction in vertebrate vascular smooth muscle.
Self-organizing adaptive neural fuzzy control for electrically driven robot manipulators
Authors: Chen C-S
Published: July 2008

A novel self-organizing adaptive neural fuzzy control (SANFC) is proposed for the trajectory tracking of an n -link robot manipulator including motor dynamics. In this control scheme, a self-organizing neural fuzzy network (SONFN) is constructed simultaneously to estimate online the system uncertainties with the structure and parameter learning phases. The fuzzy rules in the SONFN can be either generated or eliminated to obtain a suitable-sized network structure, and the adaptive tuning laws of network parameters are derived in the sense of the Lyapunov synthesis approach to ensure network convergence as well as stable control performance. A supervisory controller is used to attenuate the effects of the approximation error on the tracking error. The merits of the SANFC are that not only can the stable position tracking be achieved but also a suitable-sized network structure is found to avoid overfitting or underfitting data sets. Experiments performed on a two-link robot manipulator driven by direct current servomotors demonstrate the effectiveness of the scheme.
Are Periods of Low Atmospheric Pressure Associated with an Increased Risk of Abdominal Aortic Aneurysm Rupture?
Authors: Smith RA , Edwards PR , da Silva AF
Published: June 2008

INTRODUCTION

Seasonal variation in rates of abdominal aortic aneurysm (AAA) rupture has previously been described. However, only two studies, to date, have suggested that periods of low atmospheric pressure may account for this observation and both returned apparently contradictory findings. The objective of this study was to demonstrate whether periods of low atmospheric pressure are indeed associated with an increased likelihood of AAA rupture presentation.

PATIENTS AND METHODS

A total of 182 cases of ruptured AAA were identified retrospectively from two centres over a 6-year period from January 2000 to December 2005. Local meteorological data for the corresponding period was obtained from the UK Meteorological Office which was recorded daily at a local weather station. Statistical analysis using Student's t-test, ANOVA (Kruskal–Wallis), linear regression and multiple logistic regression was conducted to identify significant relationships from the data.

RESULTS

Days of rupture presentation were associated with a significantly lower daily mean atmospheric pressure when compared with days when no rupture occurred (P = 0.025). Multiple logistic regression demonstrated a significant association between low daily atmospheric pressure and rupture incidence (P = 0.033) which appeared to be independent of temperature. A significant seasonal trough in atmospheric pressure was observed in October and November (Kruskal–Wallis, P < 0.001); however, there was no corresponding autumnal peak in rupture incidence (P = 0.232).

CONCLUSIONS

The findings of this study appear to confirm the assertion that low atmospheric pressure is associated with an increased risk of AAA rupture on a day-to-day basis; however, no evidence was identified to support a change in policy regarding prioritising elective surgery based on seasonal risk.
The Benefit of Modified Rehabilitation and Minimally Invasive Techniques in Total Hip Replacement
Authors: Lilikakis Anastasios K , Gillespie Beryl , Villar Richard N
Published: June 2008

INTRODUCTION

We wished to assess if an intensive rehabilitation regimen alone, or one combined with modified anaesthetic and surgical techniques, can change the speed of rehabilitation or the length of hospital stay after total hip replacement.

PATIENTS AND METHODS

We compared 44 patients who had followed a traditional care pathway, with 38 patients who had rehabilitated under a new rehabilitation protocol, with 40 patients who had also received modified, minimally invasive techniques. The speed of rehabilitation was measured in terms of three specific milestones accomplished on the day after surgery.

RESULTS

We found a statistically significant improvement in the day after surgery each activity was possible. The length of hospital stay was reduced from 6.5 days to 5.4 days to 4.1 days, a difference which was also statistically significant.

CONCLUSIONS

The data support the view that a new rehabilitation protocol alone can reduce the length of hospital stay and hasten rehabilitation. The combination of modified anaesthetic and minimally invasive surgical techniques with the new rehabilitation regimen can further improve short-term outcome after total hip replacement.
Investigating Bacterial Growth in Surgical Theatres: Establishing the Effect of Laminar Airflow on Bacterial Growth on Plastic, Metal and Wood Surfaces
Authors: da Costa Alex Rodrigues , Kothari Ami , Bannister Gordon C , Blom Ashley W
Published: June 2008

INTRODUCTION

Infection is a devastating complication of surgery. Intra-operative wound contamination is a common cause of infection. A number of measures have been effective in reducing wound contamination. One such measure is laminar flow. Controversy exists as to whether it is safe to keep open instruments and implants outside the laminar flow. This study compares bacterial contamination of wood, plastic and stainless steel within and outside the laminar flow.

MATERIALS AND METHODS

Identically shaped and sized tiles were left for 90 min within and outside the laminar flow and then cultured for bacterial growth.

RESULTS

A third of metal and plastic tiles were contaminated, but only 10% of wooden tiles, suggesting that wood is a more hostile environment for bacteria. There was no difference in contamination between tiles placed inside and those placed outside the laminar flow.

CONCLUSIONS

This study suggests that placing instruments and implants outside the laminar flow is a safe practice.
The Elusive Electromyogram in the Overactive Bladder: A Spark of Understanding
Authors: Ballaro Andrew
Published: June 2008

It has been said that a technique capable of recording a urinary bladder electromyogram could be useful in the clinical evaluation of the detrusor neuropathies and myopathies implicated in the generation of lower urinary tract symptoms. However, in contrast to electromyography of skeletal and cardiac muscle, detrusor smooth muscle electromyography has remained in its infancy despite 50 years of scientific effort. The principal problems appear to be isolation of the real signal from artefacts, and the doubtful existence of electromyographic activity during cholinergic muscle contraction. The discovery of purinergic neuromuscular transmission in the overactive human bladder has renewed interest in detrusor electromyography as, in contrast to cholinergic mechanisms, purinergic mechanisms can generate extracellular electrical activity. In this paper, the development and validation of a novel technique for recording electrical activity from neurologically intact guinea-pig and human detrusor in vitro is described. A purinergic electromyographic signal is characterised and it is shown that detrusor taken from overactive human bladders has a greater propensity to generate electromyographic activity than normal by virtue of an aberrant purinergic mechanism.
Pancreas Transplantation
Authors: White SA , Manas DW
Published: June 2008

Over the last 5 years, there has been a resumed interest in treating diabetes by transplantation, particularly islet transplantation. However, despite advances being reported in Canada and the US, replication in the UK has been much more difficult. At present there is still only one treatment that can consistently reverse insulin independence in the long-term and that is whole pancreas transplantation. Long-term normoglycaemia has beneficial effects on preventing and ameliorating the secondary complications of diabetes and will be discussed.
Bilateral Retrovascular Femoral Hernia
Authors: Papanikitas Joseph , Sutcliffe Robert P , Rohatgi Ashish , Atkinson Simon
Published: June 2008

A 34-year-old woman with cystic fibrosis presented with bilateral femoral hernias, which were found to be retrovascular at operation. The hernias were not amenable to conventional open or laparoscopic repair, and were repaired using pre-peritoneal mesh inserted deep to transversalis fascia. The anatomical basis and management of uncommon variants of femoral hernia are discussed.
Preferred orientations and anisotropy in shales: Callovo-Oxfordian shale (France) and Opalinus Clay (Switzerland)
Authors: Wenk H.-R. , Voltolini M. , Mazurek M. , Van Loon L. R. , Vinsot A.
Published: June 2008

Anisotropy in clay-rich sedimentary rocks is receiving increasing attention. Seismic anisotropy is essential in the prospecting for petroleum deposits. Anisotropy of diffusion has become relevant for environmental contaminants, including nuclear waste. In both cases, the orientation of component minerals is a critical ingredient and, largely because of small grain size and poor crystallinity, the orientation distribution of clay minerals has been difficult to quantify. A method is demonstrated that relies on hard synchrotron X-rays to obtain diffraction images of shales and applies the crystallographic Rietveld method to deconvolute the images and extract quantitative information about phase fractions and preferred orientation that can then be used to model macroscopic physical properties. The method is applied to shales from European studies which investigate the suitability of shales as potential nuclear waste repositories (Meuse/Haute-Marne Underground Research Laboratory near Bure, France, and Benken borehole and Mont Terri Rock Laboratory, Switzerland). A Callovo-Oxfordian shale from Meuse/Haute-Marne shows a relatively weak alignment of clay minerals and a random distribution for calcite. Opalinus shales from Benken and Mont Terri show strong alignment of illite-smectite, kaolinite, chlorite, and calcite. This intrinsic contribution to anisotropy is consistent with macroscopic physical properties where anisotropy is caused both by the orientation distribution of crystallites and high-aspect-ratio pores. Polycrystal elastic properties are obtained by averaging single crystal properties over the orientation distribution and polyphase properties by averaging over all phases. From elastic properties we obtain anisotropies for p waves ranging from 7 to 22%.
Hydrothermal synthesis, between 75 and 150°C, of High-charge, ferric nontronites
Authors: Decarreau Alain , Petit Sabine , Martin François , Farges François , Vieillard Philippe , Joussein Emmanuel
Published: June 2008

High-charge nontronites were synthesized at 75, 90, 100, 110, 125, and 150°C from a silicoferrous starting gel with Si2FeNa2O6.nH2O composition. This gel was oxidized in contact with air and then hydrothermally treated, for a period of 4 weeks, under equilibrium water pressure. The synthesized nontronites were similar to each other, regardless of the synthesis temperature. Their structural formula, obtained from chemical analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR), Mössbauer, and X-ray absorption fine structure spectroscopies is: <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:c="http://cambridge.org/core/content" xmlns:core="http://cambridge.org/core" xmlns:m="http://cambridge.org/core/metadata" xmlns:cup="http://contentservices.cambridge.org" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest">(Si3.25Fe0.753+)Fe23+O10(OH)2Na0.75$\left( {{\rm{S}}{{\rm{i}}_{3.25}}{\rm{Fe}}_{0.75}^{3 + }} \right){\rm{Fe}}_2^{3 + }{{\rm{O}}_{10}}{\left( {{\rm{OH}}} \right)_2}{\rm{N}}{{\rm{a}}_{0.75}}$. A strictly ferric end-member of the nontronite series was therefore synthesized for the first time. The uncommon chemistry of the synthesized nontronites, notably the high level of Fe-for-Si substitution, induced particular XRD, FTIR, and differential thermal analysis-thermogravimetric analysis data. The ethylene glycol expandability of the synthetic nontronites was linked to their crystallinity and depended on the nature of the interlayer cation, moving from smectite to vermiculite-like behavior. As the synthesis temperature increased, the crystallinity of the synthesized clays increased. The nontronite obtained at 150°C had the ‘best crystallinity’, which cannot be improved by increasing synthesis time or temperature.
The pH of aqueous bentonite suspensions
Authors: Kaufhold Stephan , Dohrmann Reiner , Koch Dietrich , Houben Georg
Published: June 2008

The pH of aqueous bentonite suspensions is known to be influenced by carbonates present even in minor amounts. On the other hand, at high solid:liquid ratios (at standard pH measurement conditions: 2% w/w suspension), the type of exchangeable cation in the smectite is also known to determine pH (particularly Na+ or Ca2+). By cation-exchange tests we proved that exchanging the Ca2+ for Na+ results in an increase in the pH. However, this increase in pH was only found if excess salts were removed from the system (by washing or dialysis, respectively). The effect of the type of exchangeable cation can, at least partially, be explained by hydrolysis of Ca2+. On the other hand, a pronounced alkalinity of Na bentonites is observed which can, at least partially, be attributed to the hydrolysis of montmorillonite (Na+ is exchanged for H+ of water). The increase in the volume of the Stern layer, caused by increasing the degree of delamination, is also suggested to play a role. H+ and Na+ are concentrated in the Stern layer. Hence, increasing the Stern layer volume decreases the amount of H+ and Na+ in solution and thus increases pH. Unfortunately, both processes, montmorillonite hydrolysis and delamination, depend on the ionic strength. Distinguishing the processes quantitatively, therefore, is an analytical challenge, and impossible based on the data presented here.

To model the pore-water chemistry of clays and clay stones, all of the above-mentioned processes have to be considered. It is possible that other reactions, not identified in the present work, contribute toward the pH values of aqueous bentonite suspensions.
The behavior of Fe in ground and acid-treated vermiculite from Santa Olalla, Spain
Authors: Maqueda Celia , Romero Agua Santas , Morillo Esmeralda , Pérez-Rodríguez José L. , Lerf Anton , Wagner Friedrich Ernst
Published: June 2008

The preparation of porous materials from clay minerals by selective leaching is of interest because it yields residues with large specific surface areas that can be used as adsorbents of contaminants or as catalysts. Grinding produces surface modifications and therefore may significantly influence the leaching behavior. The aim of this paper is to study the effect of grinding and leaching on the structure of the vermiculite from Santa Olalla, Spain, using 57Fe Mössbauer spectroscopy, X-ray diffraction, infrared spectroscopy, and specific surface area (SBET) measurements. The study shows that grinding destroys the long range order of the vermiculite, but leaves the local structure in the environment of the Fe atoms intact, at least up to a grinding time of 10 min. The Mössbauer study shows that there is no Fe3+ in the tetrahedral sheets and that grinding does not lead to a significant oxidation of the structural Fe. Vermiculite ground for 4 min and leached with 1 M HCl solution at 80°C over a 24 h period was decomposed to X-ray amorphous silica with a very large specific surface area (SBET = 720 m2g−1) and with total pore volume of 0.586 cm3 g−1, whereas an unground sample leached with the same acid concentration yielded a specific surface area of only 504 m2 g−1. Most of the Mg2+ and Al3+ are removed from the ground sample after leaching with 1 M HCl, while large percentages of Fe2O3 remain with the X-ray amorphous silica. In unground vermiculite leached with 1 M HCl, a considerable amount of vermiculite remains in the residue. A sample ground for 4 min and treated with 0.25 M HCl also shows the typical vermiculite Mössbauer spectrum with an Fe2+/Fe3+ ratio similar to that of the unground vermiculite. The samples ground for 2 or 4 min and treated with 1 M HCl solution have an orange color and, according to the Mössbauer spectra, only Fe3+ remains. Mössbauer spectra of these samples taken at 4.2 K reveal the presence of akaganéite.
Renal Collecting Duct Carcinoma in a Dog
Authors: Kobayashi N. , Suzuki K. , Shibuya H. , Sato T. , Aoki I. , Nagashima Y.
Published: June 2008

An 8-year-old, male, mongrel dog developed severe cough and anorexia and died within 3 months. Autopsy revealed an invasive grayish-white mass in the right kidney and multiple nodules in the lungs, thoracic wall, and spleen. Histologically, the renal mass and the other nodules were mainly composed of papillotubular structures lined by oval-to-polygonal pleomorphic cells. The cells were reactive with DBA, PNA, and UEA-1 lectins and positive for vimentin but negative for CD10 and high molecular weight cytokeratin. Because of its histological, histochemical, and immunohistochemical similarities with human collecting duct carcinoma (CDC), a diagnosis of renal collecting duct carcinoma with pulmonary, thoracic, and splenic metastases was established. To our knowledge, this is the first case report of CDC in animals.
Polycystic Ovary Syndrome with Endometrial Hyperplasia in a Cynomolgus Monkey (Macaca fascicularis)
Authors: Arifin E. , Shively C. A. , Register T. C. , Cline J. M.
Published: June 2008

A 13-year-old, obese, female cynomolgus monkey ( Macaca fascicularis) was observed in a 5-year neurobehavioral study and was humanely euthanatized for experimental purposes. During this observational study, the monkey was noted to ovulate only rarely (0–3 times a year), with a prolonged menstrual cycle length (up to 161 days), hyperandrogenism (androstenedione area under the curve in response to adrenocorticotropic hormone up to 27.64 ng/ml), and hyperinsulinemia (fasting insulin up to 65.85 μIU/ml). This animal's body mass index was 65.46 kg/m2, with central obesity. On postmortem examination, the uterus was moderately enlarged, with an eccentric lumen and a broad-based endometrial polyp that consisted of complex glandular hyperplasia with atypia. Both ovaries contained many 2- to 3-mm follicles, without any corpora lutea. A diagnosis of polycystic ovary syndrome was made based on the clinical history, endocrinology, and gross and histopathologic findings.
Patent Ductus Arteriosus in Murrah Buffalos
Authors: Ecco R. , Snel-Oliveira M. V. , Barros R. M. , Santos H. L.
Published: June 2008

Two cases of patent ductus arteriosus are described in 2 Murrah buffalos, a 7.5-month-old heifer calf and a 5-month-old bull calf. The main clinical signs consisted of exercise intolerance, dyspnea, and tachycardia. At necropsy, lesions were consistent with congestive heart failure as indicated by dependent subcutaneous edema, body cavity effusions, and nutmeg liver. The lungs were extensively atelectatic. The heart was enlarged and had a globous shape. The ductus arteriosus, measuring 0.8 cm in length and 0.4 cm in caliber, was patent. The proximal pulmonary artery had an approximately 50-mm-long aneurysm. Eccentric cardiac hypertrophy was evident primarily in the right but to a lesser degree also in the left ventricle. Additionally, there was diffuse subendocardial fibrosis in the left and right ventricle. To the best of the authors' knowledge, patent ductus arteriosus was not previously described in buffalos. Since both calves were sired by the same bull, it is possible that this cardiac anomaly has a hereditary basis.